[SERVER] iscsi: Add a lot of Doxygen comments, some general additions

2 files changed, 5479 insertions, 2672 deletions

diff --git a/src/server/iscsi.c b/src/server/iscsi.c
index 7334bd6..49e0f46 100644
--- a/src/server/iscsi.c
+++ b/src/server/iscsi.c
@@ -34,13 +34,15 @@
  * @brief iSCSI implementation for DNBD3.
  *
  * This file contains the iSCSI implementation according to
- * RFC7143 for dnbd3-server.
+ * RFC7143 for dnbd3-server.\n
  * All server-side network sending and client-side network
- * receiving code is done here.
+ * receiving code is done here.\n
  * @see https://www.rfc-editor.org/rfc/rfc7143
  */
 
 /**
+ * @brief Allocates and appends a buffer and sprintf's it.
+ *
  * Merges multiple strings using printf style formatting
  * and allocates memory for holding the result.
  *
@@ -77,6 +79,8 @@ uint8_t *iscsi_vsprintf_append_realloc(char *buf, const char *format, va_list ar
 }
 
 /**
+ * @brief Allocates and appends a buffer and sprintf's it.
+ *
  * Merges strings using printf style formatting and allocates
  * memory for holding the result.
  *
@@ -97,6 +101,8 @@ uint8_t *iscsi_sprintf_append_realloc(char *buf, const char *format, ...)
 }
 
 /**
+ * @brief Allocates a buffer and sprintf's it.
+ *
  * Merges strings using printf style formatting and allocates
  * memory for holding the result.
  *
@@ -110,6 +116,8 @@ uint8_t *iscsi_vsprintf_alloc(const char *format, va_list args)
 }
 
 /**
+ * @brief Allocates a buffer and sprintf's it.
+ *
  * Allocates a buffer large enough to hold printf style
  * string concatenation and fills it using vspnrintf.
  *
@@ -129,11 +137,13 @@ uint8_t *iscsi_sprintf_alloc(const char *format, ... )
 }
 
 /**
+ * @brief Creates an empty hash map with either specified or default capacity.
+ *
  * Creates a ultra hardcore speed optimized empty hash map and
- * allocates enough buckets to hold default capacity elements.
+ * allocates enough buckets to hold default capacity elements.\n
  * The speed optimizations require all keys having a size of
  * a multiple of 8 bytes with zero padding. Also the capacity
- * always nas to be a power of two.
+ * always nas to be a power of two.\n
  * TODO: Move all hash map related functions to different source file
  * later and implement in a lock-free way for better concurrency.
  *
@@ -186,6 +196,8 @@ iscsi_hashmap *iscsi_hashmap_create(const uint capacity)
 }
 
 /**
+ * @brief Deallocates the hash map objects and buckets, not elements. Use iscsi_hashmap_iterate to deallocate the elements themselves.
+ *
  * Deallocates all buckets and the hash map itself allocated
  * by iscsi_hashmap_create. The elements associated with the
  * buckets are NOT freed by this function, this has to be done
@@ -205,6 +217,8 @@ void iscsi_hashmap_destroy(iscsi_hashmap *map)
 }
 
 /**
+ * @brief Puts an old bucket into a resized hash map.
+ *
  * Puts an old bucket into a resized hash map.
  *
  * @param[in] map Pointer to resized hash map, may NOT be NULL, so
@@ -231,6 +245,8 @@ static iscsi_hashmap_bucket *iscsi_hashmap_resize_entry(iscsi_hashmap *map, cons
 }
 
 /**
+ * @brief Resizes a hash map by doubling its bucket capacity and purges any removed buckets.
+ *
  * Resizes a hash map by doubling its bucket capacity. if any
  * buckets have been removed, they are finally purged. The
  * old bucket list is freed after the resize operation has
@@ -281,6 +297,8 @@ static int iscsi_hashmap_resize(iscsi_hashmap *map)
 }
 
 /**
+ * @brief Calculates the hash code of data with a specified length.
+ *
  * Calculates the hash code of data with a specified length.
  *
  * @param[in] data Pointer to data to be hashed, NULL is NOT
@@ -306,6 +324,8 @@ static inline uint32_t iscsi_hashmap_hash_data(const uint8_t *data, const size_t
 }
 
 /**
+ * @brief Finds a bucket by key of a specified hash map by key, key size and hash code.
+ *
  * Finds a bucket by key of a specified hash map by
  * key, key size and hash code. This function may
  * only be called if the bucket is guaranteed to
@@ -335,8 +355,10 @@ static iscsi_hashmap_bucket *iscsi_hashmap_find_entry(iscsi_hashmap *map, const
 }
 
 /**
+ * @brief Creates a key suitable for hashmap usage (ensures 8-byte boundary and zero padding).
+ *
  * Creates a key from data and size and ensures
- * its requirements for usage in hash map buckets.
+ * its requirements for usage in hash map buckets.\n
  * Currently keys to be used in a hash map bucket
  * require a size of multiple by 8 bytes with
  * the zero padding.
@@ -366,6 +388,8 @@ uint8_t *iscsi_hashmap_key_create(const uint8_t *data, const size_t len)
 }
 
 /**
+ * @brief Deallocates all resources acquired by iscsi_hashmap_create_key.
+ *
  * Deallocates a key allocated with the function
  * iscsi_hashmap_key_create.
  *
@@ -377,6 +401,8 @@ void iscsi_hashmap_key_destroy(uint8_t *key) {
 }
 
 /**
+ * @brief Deallocates all key / value pairs in a hash map by calling free (default destructor).
+ *
  * Default callback function for deallocation of
  * allocated hash map resources by simply calling
  * free.
@@ -387,7 +413,7 @@ void iscsi_hashmap_key_destroy(uint8_t *key) {
  * be a multiple of 8 bytes which is NOT checked, so
  * be careful.
  * @param[in] value Value of the key, NULL is allowed.
- * @param[in] user_data This argument is not used by
+ * @param[in,out] user_data This argument is not used by
  * this function and should be always NULL for now, as
  * there is a possibility for future usage.
  * @return Always returns 0 as this function cannot fail.
@@ -403,9 +429,11 @@ int iscsi_hashmap_key_destroy_value_callback(uint8_t *key, const size_t key_size
 }
 
 /**
+ * @brief Assigns key / value pair to hash map without making copies.
+ *
  * Adds a key / value pair to a specified hash map
  * bucket list, if it doesn't exist already. The
- * buckets are resized automatically if required.
+ * buckets are resized automatically if required.\n
  * This function neither does make a copy of the key,
  * nor of the value. Keys should be allocated using
  * the function iscsi_hashmap_key_create or freed by
@@ -453,12 +481,14 @@ int iscsi_hashmap_put(iscsi_hashmap *map, const uint8_t *key, const size_t key_s
 }
 
 /**
+ * @brief Assigns key / value pair to hash map without making copies.
+ *
  * Adds a key / value pair if it doesn't exist
  * using the value of `*out_in_val`. If the pair
  * does exist, value will be set in `*out_in`,
  * meaning the value of the pair will be in
  * '*out_in` regardless of whether or not it it
- * existed in the first place.
+ * existed in the first place.\n
  * The buckets are resized automatically if required.
  * This function neither does make a copy of the key,
  * nor of the value. Keys should be allocated using
@@ -511,13 +541,15 @@ int iscsi_hashmap_get_put(iscsi_hashmap *map, const uint8_t *key, const size_t k
 }
 
 /**
+ * @brief Assigns key / value pair to hash map without making copies with callback function in case the key already exists.
+ *
  * Adds a key / value pair to a specified hash map
  * bucket list. If the key already exists, it will
  * be overwritten and a callback function will be
  * invoked in order to allow, e.g. deallocation of
  * resources, if necessary. The buckets are resized
  * automatically if required. This function neither
- * does make a copy of the key, nor of the value.
+ * does make a copy of the key, nor of the value.\n
  * Keys should be allocated using the function
  * iscsi_hashmap_key_create or freed by using
  * iscsi_hashmap_key_destroy in order to ensure the
@@ -538,7 +570,7 @@ int iscsi_hashmap_get_put(iscsi_hashmap *map, const uint8_t *key, const size_t k
  * overwritten key and value pair. The function is
  * invoked just before overwriting the old values.
  * This may NOT be NULL, so take caution.
- * @param[in] user_data Pointer to user specific data
+ * @param[in,out] user_data Pointer to user specific data
  * passed to the callback function in case more
  * information is needed.
  * @return -1 in case adding key / value pair would
@@ -580,6 +612,8 @@ int iscsi_hashmap_put_free(iscsi_hashmap *map, const uint8_t *key, const size_t
 }
 
 /**
+ * @brief Checks whether a specified key exists.
+ *
  * Checks whether a specified key exists in a hash map.
  *
  * @param[in] map Pointer to the hash map to be searched
@@ -602,6 +636,8 @@ int iscsi_hashmap_contains(iscsi_hashmap *map, const uint8_t *key, const size_t
 }
 
 /**
+ * @brief Retrieves the value of a specified key.
+ *
  * Retrieves the value of a specified key from a hash map. Since the
  * hash map supports NULL values, it is stored in an output variable.
  *
@@ -633,6 +669,8 @@ int iscsi_hashmap_get(iscsi_hashmap *map, const uint8_t *key, const size_t key_s
 }
 
 /**
+ * @brief Marks an element for removal by setting key and value both to NULL.
+ *
  * Removes an element from the bucket list of the hash map.
  * Buckets are marked as removed by setting their key and
  * value to NULL. The actual removal will be done upon next
@@ -661,7 +699,9 @@ void iscsi_hashmap_remove(iscsi_hashmap *map, const uint8_t *key, const size_t k
 }
 
 /**
- * Removes an element from the bucket list of the hash map.
+ * @brief Marks an element for removal by setting key and value both to NULL, but invokes a callback function before actual marking for removal.
+ *
+ * Removes an element from the bucket list of the hash map.\n
  * Buckets are marked as removed by setting their key and
  * value to NULL. The actual removal will be done upon next
  * resize operation. A callback function is invoked if the
@@ -681,7 +721,7 @@ void iscsi_hashmap_remove(iscsi_hashmap *map, const uint8_t *key, const size_t k
  * key and value pair to be removed. The function is
  * invoked just before marking the key / value pair
  * as removed. This may NOT be NULL, so take caution.
- * @param[in] user_data Pointer to user specific data
+ * @param[in,out] user_data Pointer to user specific data
  * passed to the callback function in case more
  * information is needed.
  */
@@ -701,6 +741,8 @@ void iscsi_hashmap_remove_free(iscsi_hashmap *map, const uint8_t *key, const siz
 }
 
 /**
+ * @brief Retrieves the number of elements of the hash map, ignoring elements marked for removal.
+ *
  * Returns the number of elements stored in the specified
  * hash map. Elements marked for removal are not included.
  *
@@ -715,6 +757,8 @@ int iscsi_hashmap_size(iscsi_hashmap *map)
 }
 
 /**
+ * @brief Iterator with callback function invoked on each element which has not been removed.
+ *
  * An iterator through the elements of a specified
  * hash map which uses a callback function for each
  * element not marked for removal, which also can
@@ -726,7 +770,7 @@ int iscsi_hashmap_size(iscsi_hashmap *map)
  * invoked for each element not marked for removal
  * in the hash map. If the return value of the callback
  * function is below zero, the iteration will stop.
- * @param[in] user_data Pointer to user specific data
+ * @param[in,out] user_data Pointer to user specific data
  * passed to the callback function in case more
  * information is needed.
  * @return The return code from the last invoked
@@ -753,6 +797,8 @@ int iscsi_hashmap_iterate(iscsi_hashmap *map, iscsi_hashmap_callback callback, u
 }
 
 /**
+ * @brief Allocate and initialize an iSCSI BHS packet.
+ *
  * Allocates an iSCSI packet data Basic Header Segment (BHS)
  * and zero fills the structure.
  *
@@ -786,6 +832,8 @@ iscsi_bhs_packet *iscsi_create_packet()
 }
 
 /**
+ * @brief Free resources allocated by iscsi_create_packet.
+ *
  * Deallocates all aquired resources by iscsi_create_packet.
  *
  * @param[in] packet_data Pointer to packet data to deallocate. If this is
@@ -798,9 +846,11 @@ void iscsi_destroy_packet(iscsi_bhs_packet *packet_data)
 }
 
 /**
+ * @brief Allocate and initialize an iSCSI AHS packet and append to existing data stream.
+ *
  * Constructs and appends an Additional Header Segment (AHS) to already allocated
  * packet data. There is no guarantee that the pointer stays the same. Any references
- * to the old structure need to be updated!
+ * to the old structure need to be updated!\n
  * This function currently throws away any data beyond AHS.
  *
  * @param[in] packet_data Pointer to packet data to append to. If NULL, a Basic
@@ -847,6 +897,8 @@ iscsi_bhs_packet *iscsi_append_ahs_packet(iscsi_bhs_packet *packet_data, const u
 }
 
 /**
+ * @brief Counts number of AHS packets in an iSCSI data packet stream.
+ *
  * Gets the total number of AHS packets.
  *
  * @param[in] packet_data Pointer to packet data of which the
@@ -878,6 +930,8 @@ int iscsi_get_ahs_packets(const iscsi_bhs_packet *packet_data)
 }
 
 /**
+ * @brief Retrieves the pointer to an specific AHS packet by index.
+ *
  * Gets the pointer of an AHS packet by specified index.
  *
  * @param[in] packet_data Pointer to packet data of which the
@@ -914,9 +968,11 @@ iscsi_ahs_packet *iscsi_get_ahs_packet(const iscsi_bhs_packet *packet_data, cons
 }
 
 /**
- * Constructs and appends DataSegment (DS) to already allocated packet data.
+ * @brief Allocate and initialize an iSCSI DS packet and append to existing data stream.
+ *
+ * Constructs and appends DataSegment (DS) to already allocated packet data.\n
  * There is no guarantee that the pointer stays the same. Any references
- * to the old structure need to be updated!
+ * to the old structure need to be updated!\n
  * This function currently erases an already available DataSegment and
  * throws away any data beyond DS.
  *
@@ -961,7 +1017,8 @@ iscsi_bhs_packet *iscsi_append_ds_packet(iscsi_bhs_packet *packet_data, const in
 	return packet_data;
 }
 
-static const uint32_t crc32c_lut[] = { // Created with a polynomial reflect value of 0x82F63B78
+/// CRC32C lookup table. Created with a polynomial reflect value of 0x82F63B78.
+static const uint32_t crc32c_lut[] = {
 	0x00000000, 0xF26B8303, 0xE13B70F7, 0x1350F3F4, 0xC79A971F, 0x35F1141C, 0x26A1E7E8, 0xD4CA64EB,
 	0x8AD958CF, 0x78B2DBCC, 0x6BE22838, 0x9989AB3B, 0x4D43CFD0, 0xBF284CD3, 0xAC78BF27, 0x5E133C24,
 	0x105EC76F, 0xE235446C, 0xF165B798, 0x030E349B, 0xD7C45070, 0x25AFD373, 0x36FF2087, 0xC494A384,
@@ -996,7 +1053,9 @@ static const uint32_t crc32c_lut[] = { // Created with a polynomial reflect valu
 	0x79B737BA, 0x8BDCB4B9, 0x988C474D, 0x6AE7C44E, 0xBE2DA0A5, 0x4C4623A6, 0x5F16D052, 0xAD7D5351};
 
 /**
- * Calculates CRC32C with 0x82F63B78 polynomial reflect according to iSCSI specs
+ * @brief Calculates digest (CRC32C).
+ *
+ * Calculates CRC32C with 0x82F63B78 polynomial reflect according to iSCSI specs.\n
  * TODO: Implement optimized SSE4.2 and ARM versions
  *
  * @param[in] data Pointer to data to calculate CRC32C for.
@@ -1018,6 +1077,8 @@ static inline uint32_t iscsi_crc32c_update(const uint8_t *data, const uint len,
 }
 
 /**
+ * @brief Calculate and store iSCSI header digest (CRC32C).
+ *
  * Calculates header digest (CRC32C) with 0x82F63B78 polynomial reflect
  * according to iSCSI specs and stores the result in the iSCSI packet
  * data. This function cannot fail.
@@ -1034,6 +1095,8 @@ void iscsi_calc_header_digest(const iscsi_bhs_packet *packet_data)
 }
 
 /**
+ * @brief Validates a stored iSCSI header digest (CRC32C) with actual header data.
+ *
  * Verifies header digest (CRC32C) with 0x82F63B78 polynomial reflect
  * according to iSCSI specs. This function cannot fail.
  *
@@ -1051,8 +1114,10 @@ int iscsi_validate_header_digest(const iscsi_bhs_packet *packet_data)
 }
 
 /**
+ * @brief Calculate iSCSI data digest (CRC32C).
+ *
  * Calculates data digest (CRC32) with 0x82F63B78 polynomial reflect
- * of a whole DataSegment (CRC32C) according to the iSCSI specs.
+ * of a whole DataSegment (CRC32C) according to the iSCSI specs.\n
  * The resulting CRC32C will be stored in the iSCSI packet.
  *
  * @param[in] packet_data Pointer to ISCSI DS packet to calculate CRC32C for.
@@ -1073,6 +1138,8 @@ void iscsi_calc_data_digest(const iscsi_bhs_packet *packet_data, const int heade
 }
 
 /**
+ * @brief Validates a stored iSCSI data digest (CRC32C) with actual DataSegment.
+ *
  * Verifies data digest (CRC32C) with 0x82F63B78 polynomial reflect
  * according to iSCSI specs. This function cannot fail.
  *
@@ -1096,6 +1163,8 @@ int iscsi_validate_data_digest(const iscsi_bhs_packet *packet_data, const int he
 }
 
 /**
+ * @brief Validates a single text key / value pair according to iSCSI specs.
+ *
  * Validates an iSCSI protocol key and value pair for compliance
  * with the iSCSI specs.
  *
@@ -1132,6 +1201,8 @@ static int iscsi_validate_text_key_value_pair(const uint8_t *packet_data, const
 }
 
 /**
+ * @brief Validates all text key / value pairs according to iSCSI specs.
+ *
  * Validates all iSCSI protocol key and value pairs for
  * compliance with the iSCSI specs.
  *
@@ -1158,11 +1229,13 @@ static int iscsi_validate_key_value_pairs(const uint8_t *packet_data, uint len)
 		offset += rc;
 	}
 
-	return (offset != len) ? ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS : ISCSI_VALIDATE_PACKET_RESULT_OK;
+	return (iscsi_align(offset, ISCSI_ALIGN_SIZE) != iscsi_align(len, ISCSI_ALIGN_SIZE)) ? ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS : ISCSI_VALIDATE_PACKET_RESULT_OK;
 }
 
 /**
- * Checks whether packet data is an iSCSI packet or not.
+ * @brief Check if valid iSCSI packet and validate if necessarily.
+ *
+ * Checks whether packet data is an iSCSI packet or not.\n
  * Since iSCSI doesn't have a magic identifier for its packets, a
  * partial heuristic approach is needed for it. There is not always
  * a guarantee that a packet clearly belongs to iSCSI. If header
@@ -1210,8 +1283,8 @@ int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint
 
 			const iscsi_nop_out_packet *nop_out_pkt = (const iscsi_nop_out_packet *) packet_data;
 
-			if ( (*(uint16_t *) nop_out_pkt->reserved != 0) || (nop_out_pkt->reserved[2] != 0) || (nop_out_pkt->reserved2[0] != 0) || (nop_out_pkt->reserved2[1] != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
+			if ( (nop_out_pkt->flags != -0x80) || (nop_out_pkt->reserved != 0) || (nop_out_pkt->reserved2[0] != 0) || (nop_out_pkt->reserved2[1] != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Flags always MUST be 0x80 for now and remaining reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
 
 			break;
 		}
@@ -1232,43 +1305,43 @@ int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint
 
 			const iscsi_task_mgmt_func_req_packet *task_mgmt_func_req_pkt = (const iscsi_task_mgmt_func_req_packet *) packet_data;
 
-			if ( (task_mgmt_func_req_pkt->reserved != 0) || (task_mgmt_func_req_pkt->reserved2 != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
+			if ( (task_mgmt_func_req_pkt->func >= 0) || (task_mgmt_func_req_pkt->reserved != 0) || (task_mgmt_func_req_pkt->reserved2 != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Function bit 7 always MUST be set and reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
 
 			break;
 		}
 		case ISCSI_CLIENT_LOGIN_REQ : {
-			if ( (packet_data->opcode != (opcode | 0x40)) || (ahs_len != 0) || (ds_len != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Bit 6 always MUST be set, AHS and DataSegment MUST be zero according to specs -> invalid iSCSI packet data
+			if ( (packet_data->opcode != (opcode | 0x40)) || (ahs_len != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Bit 6 always MUST be set and AHS MUST be zero according to specs -> invalid iSCSI packet data
 
 			const iscsi_login_req_packet *login_req_pkt = (const iscsi_login_req_packet *) packet_data;
 
 			if ( (ISCSI_VERSION_MIN < login_req_pkt->version_min) || (ISCSI_VERSION_MAX > login_req_pkt->version_max) )
 				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_UNSUPPORTED_VERSION;
 
-			if ( (login_req_pkt->reserved != 0) || (login_req_pkt->reserved2[0] != 0) || (login_req_pkt->reserved2[1] != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
+			if ( ((login_req_pkt->flags < 0) && ((login_req_pkt->flags & ISCSI_LOGIN_REQ_FLAGS_CONTINUE) != 0)) || (login_req_pkt->flags & ~(ISCSI_LOGIN_REQ_FLAGS_CONTINUE | ISCSI_LOGIN_REQ_FLAGS_TRANSMIT) != 0) || (login_req_pkt->reserved != 0) || (login_req_pkt->reserved2[0] != 0) || (login_req_pkt->reserved2[1] != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // If C bit is set, T MUST be cleared and reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
 
 			return iscsi_validate_key_value_pairs( ((const uint8_t *) login_req_pkt) + iscsi_align(ds_len, ISCSI_ALIGN_SIZE), ds_len );
 
 			break;
 		}
 		case ISCSI_CLIENT_TEXT_REQ : {
-			if ( ((int8_t) packet_data->opcode < 0) || (ds_len == 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // MSB always MUST be cleared for this opcode and DataSegment is mandatory -> invalid iSCSI packet data
+			if ( (int8_t) packet_data->opcode < 0 )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // MSB always MUST be cleared for this opcode -> invalid iSCSI packet data
 
 			const iscsi_text_req_packet *text_req_pkt = (const iscsi_text_req_packet *) packet_data;
 
-			if ( (text_req_pkt->reserved != 0) || (text_req_pkt->reserved2[0] != 0) || (text_req_pkt->reserved2[1] != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
+			if ( ((text_req_pkt->flags < 0) && ((text_req_pkt->flags & ISCSI_TEXT_REQ_FLAGS_CONTINUE) != 0)) || (text_req_pkt->flags & ~(ISCSI_TEXT_REQ_FLAGS_CONTINUE | ISCSI_TEXT_REQ_FLAGS_FINAL) != 0) || (text_req_pkt->reserved != 0) || (text_req_pkt->reserved2[0] != 0) || (text_req_pkt->reserved2[1] != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // If C bit is set, F MUST be cleared and reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
 
 			return iscsi_validate_key_value_pairs( ((const uint8_t *) text_req_pkt) + iscsi_align(ds_len, ISCSI_ALIGN_SIZE), ds_len );
 
 			break;
 		}
 		case ISCSI_CLIENT_SCSI_DATA_OUT : {
-			if ( (packet_data->opcode != opcode) || (ds_len == 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Bits 6 and 7 always MUST be cleared for this opcode and DataSegment is mandatory -> invalid iSCSI packet data
+			if ( packet_data->opcode != opcode )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Bits 6 and 7 always MUST be cleared for this opcode -> invalid iSCSI packet data
 
 			const iscsi_scsi_data_out_req_packet *scsi_data_out_req_pkt = (const iscsi_scsi_data_out_req_packet *) packet_data;
 
@@ -1283,8 +1356,8 @@ int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint
 
 			const iscsi_logout_req_packet *logout_req_pkt = (const iscsi_logout_req_packet *) packet_data;
 
-			if ( (logout_req_pkt->reserved != 0) || (logout_req_pkt->reserved2 != 0) || (logout_req_pkt->reserved3 != 0) || (logout_req_pkt->reserved4[0] != 0) || (logout_req_pkt->reserved4[1] != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
+			if ( (logout_req_pkt->reason_code >= 0) || (logout_req_pkt->reserved != 0) || (logout_req_pkt->reserved2 != 0) || (logout_req_pkt->reserved3 != 0) || (logout_req_pkt->reserved4[0] != 0) || (logout_req_pkt->reserved4[1] != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reason code always MUST have bit 7 set and Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
 
 			break;
 		}
@@ -1294,8 +1367,8 @@ int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint
 
 			const iscsi_snack_req_packet *snack_req_pkt = (const iscsi_snack_req_packet *) packet_data;
 
-			if ( (snack_req_pkt->reserved != 0) || (snack_req_pkt->reserved2 != 0) || (snack_req_pkt->reserved3 != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
+			if ( (snack_req_pkt->type >= 0) || (snack_req_pkt->reserved != 0) || (snack_req_pkt->reserved2 != 0) || (snack_req_pkt->reserved3 != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Bit 7 of type always MUST be set and reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
 
 			break;
 		}
@@ -1310,8 +1383,8 @@ int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint
 
 			const iscsi_nop_in_packet *nop_in_pkt = (const iscsi_nop_in_packet *) packet_data;
 
-			if ( (*(uint16_t *) nop_in_pkt->reserved != 0) || (nop_in_pkt->reserved[2] != 0) || (nop_in_pkt->reserved2[0] != 0) || (nop_in_pkt->reserved2[1] != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
+			if ( (nop_in_pkt->flags != -0x80) || (nop_in_pkt->reserved != 0) || (nop_in_pkt->reserved2[0] != 0) || (nop_in_pkt->reserved2[1] != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Flags always MUST be 0x80 for now and remaining reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
 
 			break;
 		}
@@ -1319,6 +1392,11 @@ int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint
 			if ( packet_data->opcode != opcode )
 				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Bits 6 and 7 always MUST be cleared for this opcode -> invalid iSCSI packet data
 
+			const iscsi_scsi_response_packet *scsi_response_pkt = (iscsi_scsi_response_packet *) packet_data;
+
+			if ( scsi_response_pkt->flags >= 0 )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Flags always MUST have bit 7 set -> invalid iSCSI packet data
+
 			break;
 		}
 		case ISCSI_SERVER_TASK_FUNC_RES : {
@@ -1327,43 +1405,43 @@ int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint
 
 			const iscsi_task_mgmt_func_response_packet *task_mgmt_func_response_pkt = (const iscsi_task_mgmt_func_response_packet *) packet_data;
 
-			if ( (task_mgmt_func_response_pkt->reserved != 0) || (task_mgmt_func_response_pkt->reserved2 != 0) || (task_mgmt_func_response_pkt->reserved3 != 0) || (task_mgmt_func_response_pkt->reserved4 != 0) || (task_mgmt_func_response_pkt->reserved5 != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
+			if ( (task_mgmt_func_response_pkt->flags != -0x80) || (task_mgmt_func_response_pkt->reserved != 0) || (task_mgmt_func_response_pkt->reserved2 != 0) || (task_mgmt_func_response_pkt->reserved3 != 0) || (task_mgmt_func_response_pkt->reserved4 != 0) || (task_mgmt_func_response_pkt->reserved5 != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Flags must be always 0x80 for now and remaining reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
 
 			break;
 		}
 		case ISCSI_SERVER_LOGIN_RES : {
-			if ( (packet_data->opcode != opcode) || (ds_len == 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Bits 6 and 7 always MUST be cleared for this opcode -> invalid iSCSI packet data and DataSegment is mandatory
+			if ( packet_data->opcode != opcode )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Bits 6 and 7 always MUST be cleared for this opcode -> invalid iSCSI packet data is mandatory
 
 			const iscsi_login_response_packet *login_response_pkt = (const iscsi_login_response_packet *) packet_data;
 
 			if ( (ISCSI_VERSION_MIN < login_response_pkt->version_max) || (ISCSI_VERSION_MAX > login_response_pkt->version_max) || (ISCSI_VERSION_MIN < login_response_pkt->version_active) || (ISCSI_VERSION_MAX > login_response_pkt->version_active) )
 				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_UNSUPPORTED_VERSION;
 
-			if ( (login_response_pkt->reserved != 0) || (login_response_pkt->reserved2 != 0) || (login_response_pkt->reserved3 != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
+			if ( ((login_response_pkt->flags < 0) && ((login_response_pkt->flags & ISCSI_LOGIN_RESPONSE_FLAGS_CONTINUE) != 0)) || (login_response_pkt->flags & ~(ISCSI_LOGIN_RESPONSE_FLAGS_CONTINUE | ISCSI_LOGIN_RESPONSE_FLAGS_TRANSMIT) != 0) || (login_response_pkt->reserved != 0) || (login_response_pkt->reserved2 != 0) || (login_response_pkt->reserved3 != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // If C bit is set, T MUST be cleared and reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
 
 			return iscsi_validate_key_value_pairs( ((const uint8_t *) login_response_pkt) + iscsi_align(ds_len, ISCSI_ALIGN_SIZE), ds_len );
 
 			break;
 		}
 		case ISCSI_SERVER_TEXT_RES : {
-			if ( (packet_data->opcode != opcode) || (ds_len == 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Bits 6 and 7 always MUST be cleared for this opcode and DataSegment is mandatory -> invalid iSCSI packet data
+			if ( packet_data->opcode != opcode )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Bits 6 and 7 always MUST be cleared for this opcode -> invalid iSCSI packet data
 
 			const iscsi_text_response_packet *text_response_pkt = (const iscsi_text_response_packet *) packet_data;
 
-			if ( (text_response_pkt->reserved != 0) || (text_response_pkt->reserved2[0] != 0) || (text_response_pkt->reserved2[1] != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
+			if ( ((text_response_pkt->flags < 0) && ((text_response_pkt->flags & ISCSI_TEXT_RESPONSE_FLAGS_CONTINUE) != 0)) || (text_response_pkt->flags & ~(ISCSI_TEXT_RESPONSE_FLAGS_CONTINUE | ISCSI_TEXT_RESPONSE_FLAGS_FINAL) != 0) || (text_response_pkt->reserved != 0) || (text_response_pkt->reserved2[0] != 0) || (text_response_pkt->reserved2[1] != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // If C bit is set, F MUST be cleared and reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
 
 			return iscsi_validate_key_value_pairs( ((const uint8_t *) text_response_pkt) + iscsi_align(ds_len, ISCSI_ALIGN_SIZE), ds_len );
 
 			break;
 		}
 		case ISCSI_SERVER_SCSI_DATA_IN : {
-			if ( (packet_data->opcode != opcode) || (ds_len == 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Bits 6 and 7 always MUST be cleared for this opcode and DataSegment is mandatory -> invalid iSCSI packet data
+			if ( packet_data->opcode != opcode )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Bits 6 and 7 always MUST be cleared for this opcode -> invalid iSCSI packet data
 
 			const iscsi_scsi_data_in_response_packet *scsi_data_in_pkt = (const iscsi_scsi_data_in_response_packet *) packet_data;
 
@@ -1378,8 +1456,8 @@ int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint
 
 			const iscsi_logout_response_packet *logout_response_pkt = (const iscsi_logout_response_packet *) packet_data;
 
-			if ( (logout_response_pkt->reserved != 0) || (logout_response_pkt->reserved2 != 0) || (logout_response_pkt->reserved3 != 0) || (logout_response_pkt->reserved4 != 0) || (logout_response_pkt->reserved5 != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
+			if ( (logout_response_pkt->flags != -0x80) || (logout_response_pkt->reserved != 0) || (logout_response_pkt->reserved2 != 0) || (logout_response_pkt->reserved3 != 0) || (logout_response_pkt->reserved4 != 0) || (logout_response_pkt->reserved5 != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Flags must be always 0x80 for now and remaining reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
 
 			break;
 		}
@@ -1389,8 +1467,8 @@ int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint
 
 			const iscsi_r2t_packet *r2t_pkt = (const iscsi_r2t_packet *) packet_data;
 
-			if ( r2t_pkt->reserved != 0 )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved field needs to be zero, but is NOT -> invalid iSCSI packet data
+			if ( (r2t_pkt->flags != -0x80) || (r2t_pkt->reserved != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Flags must be always 0x80 for now and remaining reserved field needs to be zero, but is NOT -> invalid iSCSI packet data
 
 			break;
 		}
@@ -1400,8 +1478,8 @@ int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint
 
 			const iscsi_async_msg_packet *async_msg_pkt = (const iscsi_async_msg_packet *) packet_data;
 
-			if ( (async_msg_pkt->tag != 0xFFFFFFFFUL) || (async_msg_pkt->reserved != 0) || (async_msg_pkt->reserved2 != 0) || (async_msg_pkt->reserved3 != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT -> invalid iSCSI packet data
+			if ( (async_msg_pkt->flags != -0x80) || (async_msg_pkt->tag != 0xFFFFFFFFUL) || (async_msg_pkt->reserved != 0) || (async_msg_pkt->reserved2 != 0) || (async_msg_pkt->reserved3 != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Flags must be always 0x80 for now, remaining reserved fields need all to be zero, but are NOT and tag always MUST be 0xFFFFFFFF -> invalid iSCSI packet data
 
 			break;
 		}
@@ -1416,8 +1494,8 @@ int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint
 
 			const iscsi_reject_packet *reject_pkt = (const iscsi_reject_packet *) packet_data;
 
-			if ( (reject_pkt->tag != 0xFFFFFFFFUL) || (reject_pkt->reserved != 0) || (reject_pkt->reserved2 != 0) || (reject_pkt->reserved3 != 0) || (reject_pkt->reserved4[0] != 0) || (reject_pkt->reserved4[1] != 0) )
-				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Reserved fields need all to be zero, but are NOT, tag always MUST be 0xFFFFFFFFUL -> invalid iSCSI packet data
+			if ( (reject_pkt->flags != -0x80) || (reject_pkt->tag != 0xFFFFFFFFUL) || (reject_pkt->reserved != 0) || (reject_pkt->reserved2 != 0) || (reject_pkt->reserved3 != 0) || (reject_pkt->reserved4[0] != 0) || (reject_pkt->reserved4[1] != 0) )
+				return ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS; // Flags must be always 0x80 for now, remaining reserved fields need all to be zero, but are NOT and tag always MUST be 0xFFFFFFFF -> invalid iSCSI packet data
 
 			break;
 		}
@@ -1438,6 +1516,8 @@ int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint
 }
 
 /**
+ * @brief Extracts a single text key / value pairs out of an iSCSI packet into a hash map.
+ *
  * Parses and extracts a specific key and value pair out of an iSCSI packet
  * data stream amd puts the extracted data into a hash map to be used by
  * the iSCSI implementation.
@@ -1524,6 +1604,8 @@ static int iscsi_parse_text_key_value_pair(iscsi_hashmap *pairs, const uint8_t *
 }
 
 /**
+ * @brief Extracts all text key / value pairs out of an iSCSI packet into a hash map.
+ *
  * Parses and extracts all key and value pairs out of iSCSI packet
  * data amd puts the extracted data into a hash map to be used by
  * the iSCSI implementation.
@@ -1540,7 +1622,7 @@ static int iscsi_parse_text_key_value_pair(iscsi_hashmap *pairs, const uint8_t *
  * @retval 0 Key and value pair was parsed successfully and was added to
  * hash map.
  */
-int iscsi_parse_key_value_pairs(iscsi_hashmap **pairs, const uint8_t *packet_data, uint len, int c_bit, uint8_t **partial_pairs)
+int iscsi_parse_key_value_pairs(iscsi_hashmap *pairs, const uint8_t *packet_data, uint len, int c_bit, uint8_t **partial_pairs)
 {
 	if ( len == 0 )
 		return 0L; // iSCSI specs don't allow zero length
@@ -1615,6 +1697,8 @@ int iscsi_parse_key_value_pairs(iscsi_hashmap **pairs, const uint8_t *packet_dat
 }
 
 /**
+ * @brief Creates a single partial iSCSI packet stream out of a single text key and value pair.
+ *
  * Callback function for constructing an iSCSI packet data
  * stream for a single key=value text pair.
  *
@@ -1625,7 +1709,7 @@ int iscsi_parse_key_value_pairs(iscsi_hashmap **pairs, const uint8_t *packet_dat
  * be careful.
  * @param[in] value Value of the key, NULL creates an
  * empty key assignment.
- * @param[in] user_data Pointer to a data structure
+ * @param[in,out] user_data Pointer to a data structure
  * containing the memory buffer and length for the
  * iSCSI packet data (iscsi_key_value_pair_packet
  * structure), may NOT be NULL, so be careful.
@@ -1640,7 +1724,7 @@ int iscsi_create_key_value_pair_packet_callback(uint8_t *key, const size_t key_s
 	const uint8_t *buf = iscsi_sprintf_alloc( "%s=%s", key, ((value != NULL) ? value : "") );
 
 	if ( buf == NULL ) {
-		logadd( LOG_ERROR, "iscsi_create_key_value_pair_callback: Out of memory generating text key / value pair DataSegment" );
+		logadd( LOG_ERROR, "iscsi_create_key_value_pair_packet_callback: Out of memory generating text key / value pair DataSegment" );
 
 		return -1L;
 	}
@@ -1651,7 +1735,7 @@ int iscsi_create_key_value_pair_packet_callback(uint8_t *key, const size_t key_s
 	uint8_t *new_buf = realloc( packet_data->buf, new_len );
 
 	if ( new_buf == NULL ) {
-		logadd( LOG_ERROR, "iscsi_create_key_value_pair_callback: Out of memory generating text key / value pair DataSegment" );
+		logadd( LOG_ERROR, "iscsi_create_key_value_pair_packet_callback: Out of memory generating text key / value pair DataSegment" );
 
 		free( buf );
 
@@ -1667,6 +1751,8 @@ int iscsi_create_key_value_pair_packet_callback(uint8_t *key, const size_t key_s
 }
 
 /**
+ * @brief Creates a properly aligned iSCSI packet DataSegment out of a hash map containing text key and value pairs.
+ *
  * Creates a properly aligned iSCSI DataSegment
  * containing NUL terminated key=value pairs
  * out of an hash map. The result can directly
@@ -1723,6 +1809,8 @@ iscsi_key_value_pair_packet *iscsi_create_key_value_pairs_packet(const iscsi_has
 }
 
 /**
+ * @brief Creates data structure for an iSCSI connection request.
+ *
  * Creates a data structure for an incoming iSCSI connection request
  * from iSCSI packet data.
  *
@@ -1742,7 +1830,7 @@ iscsi_connection *iscsi_connection_create(const iscsi_login_req_packet *login_re
 		return NULL;
 	}
 
-	conn->key_value_pairs = iscsi_hashmap_create( 0UL );
+	conn->key_value_pairs = iscsi_hashmap_create( 32UL );
 
 	if ( conn->key_value_pairs == NULL ) {
 		logadd( LOG_ERROR, "iscsi_create_connection: Out of memory while allocating iSCSI text key / value pair hash map" );
@@ -1770,6 +1858,8 @@ iscsi_connection *iscsi_connection_create(const iscsi_login_req_packet *login_re
 }
 
 /**
+ * @brief Deallocates all resources acquired by iscsi_connection_create.
+ *
  * Deallocates a data structure of an iSCSI connection
  * request and all allocated hash maps which don't
  * require closing of external resources like closing
@@ -1795,6 +1885,8 @@ void iscsi_connection_destroy(iscsi_connection *conn)
 }
 
 /**
+ * @brief iSCSI connection destructor callback for hash map.
+ *
  * Callback function for deallocation of an iSCSI
  * connection stored in the hash map managing all
  * iSCSI connections.
@@ -1805,7 +1897,7 @@ void iscsi_connection_destroy(iscsi_connection *conn)
  * be a multiple of 8 bytes which is NOT checked, so
  * be careful.
  * @param[in] value Value of the key, NULL is allowed.
- * @param[in] user_data This argument is not used by
+ * @param[in,out] user_data This argument is not used by
  * this function and should be always NULL for now, as
  * there is a possibility for future usage.
  * @return Always returns 0 as this function cannot fail.
diff --git a/src/server/iscsi.h b/src/server/iscsi.h
index 8035d94..690166b 100644
--- a/src/server/iscsi.h
+++ b/src/server/iscsi.h
@@ -18,6 +18,17 @@
  *
  */
 
+/**
+ * @file iscsi.h
+ * @author Sebastian Vater
+ * @date 07 Jul 2025
+ * @brief iSCSI header for DNBD3.
+ *
+ * This file contains the header file for the iSCSI
+ * implementation according to RFC7143 for dnbd3-server.
+ * @see https://www.rfc-editor.org/rfc/rfc7143
+ */
+
 #ifndef DNBD3_ISCSI_H_
 #define DNBD3_ISCSI_H_
 
@@ -104,7 +115,7 @@ static inline void iscsi_put_be64(uint8_t *data, const uint64_t val)
 #error "Unknown CPU endianness"
 #endif
 
-// Align a value so that it's evenly divisable by n
+/// Aligns value x by rounding up, so it's evenly divisable by n.
 #define iscsi_align(x, n) (((x) + (n) - 1) & ~((n) - 1))
 
 uint8_t *iscsi_vsprintf_append_realloc(char *buf, const char *format, va_list args); // Allocates and appends a buffer and sprintf's it
@@ -112,34 +123,84 @@ uint8_t *iscsi_sprintf_append_realloc(char *buf, const char *format, ...); // Al
 uint8_t *iscsi_vsprintf_alloc(const char *format, va_list args); // Allocates a buffer and sprintf's it
 uint8_t *iscsi_sprintf_alloc(const char *format, ... ); // Allocates a buffer and sprintf's it
 
-#define ISCSI_HASHMAP_DEFAULT_CAPACITY_SHIFT 5UL // Shift factor for default capacity
-#define ISCSI_HASHMAP_DEFAULT_CAPACITY (1UL << (ISCSI_HASHMAP_DEFAULT_CAPACITY_SHIFT)) // Default capacity is 32 buckets
-#define ISCSI_HASHMAP_RESIZE_SHIFT 1UL // Number of bits to shift left when resizing
-#define ISCSI_HASHMAP_KEY_ALIGN_SHIFT 3UL // Key data shift value for alignment enforcement
-#define ISCSI_HASHMAP_KEY_ALIGN (1UL << (ISCSI_HASHMAP_KEY_ALIGN_SHIFT)) // Key data size must be multiple of 8 bytes by now
-#define ISCSI_HASHMAP_HASH_INITIAL 0x811C9DC5UL // Initial hash code
-#define ISCSI_HASHMAP_HASH_MUL 0xBF58476D1CE4E5B9ULL // Value to multiply hash code with
+/// Shift factor for default capacity.
+#define ISCSI_HASHMAP_DEFAULT_CAPACITY_SHIFT 5UL
+
+/// Default capacity is 32 buckets.
+#define ISCSI_HASHMAP_DEFAULT_CAPACITY (1UL << (ISCSI_HASHMAP_DEFAULT_CAPACITY_SHIFT))
+
+/// Number of bits to shift left when resizing.
+#define ISCSI_HASHMAP_RESIZE_SHIFT 1UL
+
+/// Key data shift value for alignment enforcement.
+#define ISCSI_HASHMAP_KEY_ALIGN_SHIFT 3UL
+
+/// Key data size must be multiple of 8 bytes by now.
+#define ISCSI_HASHMAP_KEY_ALIGN (1UL << (ISCSI_HASHMAP_KEY_ALIGN_SHIFT))
 
+/// Initial hash code.
+#define ISCSI_HASHMAP_HASH_INITIAL 0x811C9DC5UL
+
+/// Value to multiply hash code with.
+#define ISCSI_HASHMAP_HASH_MUL 0xBF58476D1CE4E5B9ULL
+
+/**
+ * @brief Hash map bucket containing key, value and hash code.
+ *
+ * This structure is used by the iSCSI hash map implementation
+ * in order to maintain the elements.
+ */
 typedef struct iscsi_hashmap_bucket {
-	struct iscsi_hashmap_bucket *next; // Must be first element
+    /// Next bucket, must be first element.
+	struct iscsi_hashmap_bucket *next;
+
+    /// Data used as key, must be aligned to 8 bytes and zero padded.
+	uint8_t *key;
+
+    /// Size of key, must be a multiple of 8 bytes.
+	size_t key_size;
 
-	uint8_t *key; // Data used as key, zero padding
-	size_t key_size; // Size of key, must be a multiple of 8 bytes
-	uint32_t hash; // Hash code
-	uint8_t *value; // Value
+    /// Hash code for the key.
+	uint32_t hash;
+
+    /// Associate4d value to the key, NULL is allowed.
+	uint8_t *value;
 } iscsi_hashmap_bucket;
 
+/**
+ * @brief Hash map containing an expandable list of buckets
+ *
+ * This structure is used by the ultra performant hash map
+ * implementation. It uses a linked list allowing fast
+ * insertions. Elements can be removed and are marked for
+ * deletion until a resize operation is necessary.
+ */
 typedef struct iscsi_hashmap {
-	iscsi_hashmap_bucket *buckets; // Hashmap buckets
-	uint capacity; // Current capacity in elements
+    /// Linked list containing the hash map buckets.
+	iscsi_hashmap_bucket *buckets;
+
+    /// Current bucket capacity, MUST be a power of two.
+    uint capacity;
+
+    /// Current capacity threshold triggering resize operation.
 	uint cap_load; // Capacity load threshold before next resize
-	uint count; // Number of buckets
-	uint removed_count; // Number of removed buckets
-	iscsi_hashmap_bucket *first; // First bucket of linked list
-	iscsi_hashmap_bucket *last; // Last bucket, allows faster traversion
+
+	/// Current count of buckets including ones marked for removal.
+	uint count;
+
+    /// Number of buckets marked for removal.
+    uint removed_count;
+
+    /// First linked list bucket for fast insertion.
+    iscsi_hashmap_bucket *first;
+
+    /// Last linked list bucket for faster traversion.
+	iscsi_hashmap_bucket *last;
 } iscsi_hashmap;
 
 /**
+ * @brief A Callback for iterating over map, freeing and removing entries. user_data is free for personal use.
+ *
  * Callback function. This is a pointer to a
  * function for various purposes like iterating
  * through a hash map. It is also used for replacing
@@ -151,6 +212,11 @@ typedef struct iscsi_hashmap {
  * be a multiple of 8 bytes which is NOT checked, so
  * be careful.
  * @param[in] value Value of the key, NULL is allowed.
+ * @param[in,out] user_data User data to be used by the
+ * callback function. User data can be modified if
+ * desired and may also be NULL if the callback
+ * function handles this case. See the documentation
+ * of the callback implementation for details.
  * @return A negative result indicates as fatal error,
  * 0 means successful operation and a positive value
  * indicates a non-fatal error or a warning.
@@ -158,8 +224,8 @@ typedef struct iscsi_hashmap {
 typedef int (*iscsi_hashmap_callback)(uint8_t *key, const size_t key_size, uint8_t *value, uint8_t *user_data); // A Callback for iterating over map, freeing and removing entries.
                                                                                                                 // user_data is free for personal use
 
-iscsi_hashmap *hashmap_create(const uint capacity); // Creates an empty hash map with default capacity specified as above
-void iscsi_hashmap_destroy(iscsi_hashmap *map); // Deallocates the hash map objects and buckets, not elements.
+iscsi_hashmap *iscsi_hashmap_create(const uint capacity); // Creates an empty hash map with either specified or default capacity
+void iscsi_hashmap_destroy(iscsi_hashmap *map); // Deallocates the hash map objects and buckets, not elements
                                                 // Use iscsi_hashmap_iterate to deallocate the elements themselves
 uint8_t *iscsi_hashmap_key_create(const uint8_t *data, const size_t len); // Creates a key suitable for hashmap usage (ensures 8-byte boundary and zero padding)
 void iscsi_hashmap_key_destroy(uint8_t *key); // Deallocates all resources acquired by iscsi_hashmap_create_key
@@ -169,7 +235,7 @@ int iscsi_hashmap_get_put(iscsi_hashmap *map, const uint8_t *key, const size_t k
 int iscsi_hashmap_put_free(iscsi_hashmap *map, const uint8_t *key, const size_t key_size, uint8_t *value, iscsi_hashmap_callback callback, uint8_t *user_data); // Assigns key / value pair to hash map without making copies
                                                                                                                                                                 // with callback function in case the key already exists
 int iscsi_hashmap_contains(iscsi_hashmap *map, const uint8_t *key, const size_t key_size); // Checks whether a specified key exists
-int iscsi_hashmap_get(iscsi_hashmap *map, const uint8_t *key, const size_t key_size, uint8_t **out_val); // Retrieves the value of a specified key
+int iscsi_hashmap_get(iscsi_hashmap *map, const uint8_t *key, const size_t key_size, uint8_t **out_value); // Retrieves the value of a specified key
 void iscsi_hashmap_remove(iscsi_hashmap *map, const uint8_t *key, const size_t key_size); // Marks an element for removal by setting key and value both to NULL
 void iscsi_hashmap_remove_free(iscsi_hashmap *map, const uint8_t *key, const size_t key_size, iscsi_hashmap_callback callback, uint8_t *user_data); // Marks an element for removal by setting key and value both to NULL,
                                                                                                                                                     // but invokes a callback function before actual marking for removal.
@@ -179,1374 +245,3138 @@ int iscsi_hashmap_iterate(iscsi_hashmap *map, iscsi_hashmap_callback callback, u
 /* iSCSI protocol stuff (all WORD/DWORD/QWORD values are big endian by default
    unless specified otherwise). */
 
-#define ISCSI_BHS_SIZE 48UL // iSCSI Basic Header Segment size
-#define ISCSI_DIGEST_SIZE 4UL // iSCSI header and data digest size (CRC32C)
-#define ISCSI_ALIGN_SIZE 4UL // iSCSI packet data alignment (BHS, AHS and DS)
+/// iSCSI Basic Header Segment size.
+#define ISCSI_BHS_SIZE 48UL
+
+/// iSCSI header and data digest size (CRC32C).
+#define ISCSI_DIGEST_SIZE 4UL
+
+/// iSCSI packet data alignment (BHS, AHS and DataSegment).
+#define ISCSI_ALIGN_SIZE 4UL
+
+/// Current minimum iSCSI protocol version supported by this implementation.
+#define ISCSI_VERSION_MIN 0
 
-#define ISCSI_VERSION_MIN 0 // Current minimum iSCSI protocol version supported by this implementation
-#define ISCSI_VERSION_MAX 0 // Current maximum iSCSI protocol version supported by this implementation
+/// Current maximum iSCSI protocol version supported by this implementation.
+#define ISCSI_VERSION_MAX 0
 
-// CRC32C constants for header and data digest
+
+/// CRC32C initial constant for header and data digest.
 #define ISCSI_CRC32C_INITIAL      0xFFFFFFFFUL
+
+/// CRC32C initial constant for header and data digest.
 #define ISCSI_CRC32C_XOR          0xFFFFFFFFUL
 
-// iSCSI initiator (client) command opcodes
-#define ISCSI_CLIENT_NOP_OUT        0x00 // NOP-Out
-#define ISCSI_CLIENT_SCSI_CMD       0x01 // SCSI Command (encapsulates a SCSI Command Descriptor Block)
-#define ISCSI_CLIENT_TASK_FUNC_REQ  0x02 // SCSI Task Management Function Request
-#define ISCSI_CLIENT_LOGIN_REQ      0x03 // Login Request
-#define ISCSI_CLIENT_TEXT_REQ       0x04 // Text Request
-#define ISCSI_CLIENT_SCSI_DATA_OUT  0x05 // SCSI Data-Out (for write operations)
-#define ISCSI_CLIENT_LOGOUT_REQ     0x06 // Logout Request
-#define ISCSI_CLIENT_SNACK_REQ      0x10 // SNACK Request
-#define ISCSI_CLIENT_VENDOR_CODE1   0x1C // Vendor-specific code #1
-#define ISCSI_CLIENT_VENDOR_CODE2   0x1D // Vendor-specific code #2
-#define ISCSI_CLIENT_VENDOR_CODE3   0x1E // Vendor-specific code #3
-
-#define ISCSI_CLIENT_FIRST_OPCODE   0x00 // First client opcode value
-#define ISCSI_CLIENT_LAST_OPCODE    0x1F // Last client opcode value
-
-// iSCSI target (server) command opcodes
-#define ISCSI_SERVER_NOP_IN         0x20 // NOP-In
-#define ISCSI_SERVER_SCSI_RESPONSE  0x21 // SCSI Response - contains SCSI status and possibly sense information or other response information
-#define ISCSI_SERVER_TASK_FUNC_RES  0x22 // SCSI Task Management Function Response
-#define ISCSI_SERVER_LOGIN_RES      0x23 // Login Response
-#define ISCSI_SERVER_TEXT_RES       0x24 // Text Response
-#define ISCSI_SERVER_SCSI_DATA_IN   0x25 // SCSI Data-In (for read operations)
-#define ISCSI_SERVER_LOGOUT_RES     0x26 // Logout Response
-#define ISCSI_SERVER_READY_XFER     0x31 // Ready To Transfer (R2T) - sent by target when it is ready to receive data
-#define ISCSI_SERVER_ASYNC_MSG      0x32 // Asynchronous Message - sent by target to indicate certain special conditions
-#define ISCSI_SERVER_VENDOR_CODE1   0x3C // Vendor-specific code #1
-#define ISCSI_SERVER_VENDOR_CODE2   0x3D // Vendor-specific code #2
-#define ISCSI_SERVER_VENDOR_CODE3   0x3E // Vendor-specific code #3
-#define ISCSI_SERVER_REJECT         0x3F // Reject
-
-#define ISCSI_SERVER_FIRST_OPCODE   0x20 // First client opcode value
-#define ISCSI_SERVER_LAST_OPCODE    0x3F // Last client opcode value
-
-#define ISCSI_OPCODE_MASK           0x3F // ISCSI opcode bit mask (bits 0-5 used)
-#define ISCSI_GET_OPCODE(x) ((x) & ISCSI_OPCODE_MASK) // Funky macro to get iSCSI packet opcode
 
+/// iSCSI initiator (client) command opcode: NOP-Out.
+#define ISCSI_CLIENT_NOP_OUT        0x00
+
+/// iSCSI initiator (client) command opcode: SCSI Command (encapsulates a SCSI Command Descriptor Block).
+#define ISCSI_CLIENT_SCSI_CMD       0x01
+
+/// iSCSI initiator (client) command opcode: SCSI Task Management Function Request.
+#define ISCSI_CLIENT_TASK_FUNC_REQ  0x02
+
+/// iSCSI initiator (client) command opcode: Login Request.
+#define ISCSI_CLIENT_LOGIN_REQ      0x03
+
+/// iSCSI initiator (client) command opcode: Text Request.
+#define ISCSI_CLIENT_TEXT_REQ       0x04
+
+/// iSCSI initiator (client) command opcode: SCSI Data-Out (for write operations).
+#define ISCSI_CLIENT_SCSI_DATA_OUT  0x05
+
+/// iSCSI initiator (client) command opcode: Logout Request.
+#define ISCSI_CLIENT_LOGOUT_REQ     0x06
+
+/// iSCSI initiator (client) command opcode: Selective Negative / Sequence Number Acknowledgment (SNACK) Request.
+#define ISCSI_CLIENT_SNACK_REQ      0x10
+
+/// iSCSI initiator (client) command opcode: Vendor-specific code #1.
+#define ISCSI_CLIENT_VENDOR_CODE1   0x1C
+
+/// iSCSI initiator (client) command opcode: Vendor-specific code #2.
+#define ISCSI_CLIENT_VENDOR_CODE2   0x1D
+
+/// iSCSI initiator (client) command opcode: Vendor-specific code #3.
+#define ISCSI_CLIENT_VENDOR_CODE3   0x1E
+
+/// First iSCSI initiator (client) command opcode.
+#define ISCSI_CLIENT_FIRST_OPCODE   0x00
+
+/// Last iSCSI initiator (client) command opcode.
+#define ISCSI_CLIENT_LAST_OPCODE    0x1F
+
+
+/// iSCSI target (server) command opcode: NOP-In.
+#define ISCSI_SERVER_NOP_IN         0x20
+
+/// iSCSI target (server) command opcode: SCSI Response - contains SCSI status and possibly sense information or other response information.
+#define ISCSI_SERVER_SCSI_RESPONSE  0x21
+
+/// iSCSI target (server) command opcode: SCSI Task Management Function Response.
+#define ISCSI_SERVER_TASK_FUNC_RES  0x22
+
+/// iSCSI target (server) command opcode: Login Response.
+#define ISCSI_SERVER_LOGIN_RES      0x23
+
+/// iSCSI target (server) command opcode: Text Response.
+#define ISCSI_SERVER_TEXT_RES       0x24
+
+/// iSCSI target (server) command opcode: SCSI Data-In (for read operations).
+#define ISCSI_SERVER_SCSI_DATA_IN   0x25
+
+/// iSCSI target (server) command opcode: Logout Response.
+#define ISCSI_SERVER_LOGOUT_RES     0x26
+
+/// iSCSI target (server) command opcode: Ready To Transfer (R2T) - sent by target when it is ready to receive data.
+#define ISCSI_SERVER_READY_XFER     0x31
+
+/// iSCSI target (server) command opcode: Asynchronous Message - sent by target to indicate certain special conditions.
+#define ISCSI_SERVER_ASYNC_MSG      0x32
+
+/// iSCSI target (server) command opcode: Vendor-specific code #1.
+#define ISCSI_SERVER_VENDOR_CODE1   0x3C
+
+/// iSCSI target (server) command opcode: Vendor-specific code #2.
+#define ISCSI_SERVER_VENDOR_CODE2   0x3D
+
+/// iSCSI target (server) command opcode: Vendor-specific code #3.
+#define ISCSI_SERVER_VENDOR_CODE3   0x3E
+
+/// iSCSI target (server) command opcode: Reject.
+#define ISCSI_SERVER_REJECT         0x3F
+
+
+/// First iSCSI target (server) command opcode.
+#define ISCSI_SERVER_FIRST_OPCODE   0x20
+
+/// Last iSCSI target (server) command opcode.
+#define ISCSI_SERVER_LAST_OPCODE    0x3F
+
+
+/// iSCSI opcode bit mask (bits 0-5 used).
+#define ISCSI_OPCODE_MASK           0x3F
+
+/// Macro which extracts iSCSI packet data opcode out of opcode byte
+#define ISCSI_GET_OPCODE(x) ((x) & ISCSI_OPCODE_MASK)
+
+/**
+ * @brief iSCSI Basic Header Segment packet data.
+ *
+ * This structure contains the basic iSCSI packet
+ * data and is shared among all opcodes. This has
+ * to be used before the opcode of the packet data
+ * has been determined.
+ */
 typedef struct __attribute__((packed)) iscsi_bhs_packet {
-    uint8_t opcode; // Command opcode (see above)
-    uint8_t opcode_fields[3]; // Opcode-specific fields
-    uint8_t total_ahs_len; // Total AHS length
-    uint8_t ds_len[3]; // Data segment length
+    /// Command opcode.
+    uint8_t opcode;
+
+    /// Opcode-specific fields.
+    uint8_t opcode_fields[3];
+
+    /// Total length of AHS (Advanced Header Segment).
+    uint8_t total_ahs_len;
+
+    /// Length of Data Segment.
+    uint8_t ds_len[3];
+
     union {
-        uint64_t lun; // LUN bitmask
-        uint8_t opcode_spec[8];  // Opcode-specific fields
+        /// SCSI LUN bit mask.
+        uint64_t lun;
+
+        /// Opcode-specific fields.
+        uint8_t opcode_spec[8];
     } lun_opcode;
-    uint32_t init_task_tag; // Initiator task tag
+
+    /// Initiator Task Tag (ITT).
+    uint32_t init_task_tag;
+
+    /// Opcode-specific fields.
     uint8_t opcode_spec_fields[28];
 } iscsi_bhs_packet;
 
-#define ISCSI_AHS_TYPE_EXT_CDB_PACKET                   0x01    // Command Descriptor Block (CDB)
+
+/// iSCSI AHS type: Extended Command Descriptor Block (CDB).
+#define ISCSI_AHS_TYPE_EXT_CDB_PACKET                   0x01
+
+/// iSCSI AHS type: Bidirectional Read Expected Data Transfer Length.
 #define ISCSI_AHS_TYPE_BIDI_READ_EXP_XFER_AHS_PACKET    0x02
 
+
+/**
+ * @brief iSCSI Advanced Header Segment packet data.
+ *
+ * This structure contains the advanced iSCSI packet
+ * data and is shared among all opcodes. This has
+ * to be used before the opcode of the packet data
+ * has been determined.
+ */
 typedef struct __attribute__((packed)) iscsi_ahs_packet {
-    uint16_t len; // AHSLength
-    uint8_t type; // AHSType
-    uint8_t specific; // AHS-Specific
-    uint8_t data[0]; // AHS-Specific data
+    /// AHSLength.
+    uint16_t len;
+
+    /// AHSType.
+    uint8_t type;
+
+    /// AHS-Specific.
+    uint8_t specific;
+
+    /// AHS-Specific data.
+    uint8_t data[0];
 } iscsi_ahs_packet;
 
-/* There are 16 bytes in the CDB field to accommodate the commonly used
-   CDBs.  Whenever the CDB is larger than 16 bytes, an Extended CDB AHS
-   MUST be used to contain the CDB spillover.
-*/
+/**
+ * @brief iSCSI CDB packet data structure.
+ *
+ * There are 16 bytes in the CDB field to accommodate the commonly used
+ * CDBs. Whenever the CDB is larger than 16 bytes, an Extended CDB AHS
+ * MUST be used to contain the CDB spillover.
+ */
 typedef struct __attribute__((packed)) iscsi_cdb {
     uint8_t data[16];
 } iscsi_cdb;
 
-/* This type of AHS MUST NOT be used if the CDBLength is less than 17.
-   The length includes the reserved byte 3.
-*/
+/**
+ * @brief iSCSI Extended CDB AHS packet data structure.
+ *
+ * This type of AHS MUST NOT be used if the CDBLength is less than 17.
+ * The length includes the reserved byte 3.
+ */
 typedef struct __attribute__((packed)) iscsi_ext_cdb_ahs_packet {
-    uint16_t len; // AHSLength - (CDBLength - 15)
-    uint8_t type; // Identifier (always 0x01 according to specs)
-    uint8_t reserved; // Reserved for future usage
-    uint8_t data[0]; // ExtendedCDB
+    /// AHSLength: AHSLength - (CDBLength - 15).
+    uint16_t len;
+
+    // AHSType: Identifier (always 1 according to iSCSI specifications).
+    uint8_t type;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint8_t reserved;
+
+    /// ExtendedCDB.
+    uint8_t data[0];
 } iscsi_ext_cdb_ahs_packet;
 
+/**
+ * @brief iSCSI Bidirectional Read Expected Data Transfer Length AHS packet data structure.
+ *
+ * This structure is used to determine the bidirectional read
+ * expected data transfer length.
+ */
 typedef struct __attribute__((packed)) iscsi_bidi_read_exp_xfer_ahs_packet {
-    uint16_t len; // Always 0x0005 according to specs
+    /// AHSLength: Always 5 according to ISCSI specifications for now.
+    uint16_t len;
+
+    /// AHSType: Always 2 according to ISCSI specifications for now.
     uint8_t type; // Identifier (always 0x02 according to specs)
-    uint8_t reserved; // Reserved for future usage
-    uint32_t bidi_read_exp_xfer_len; // Bidirectional Read Expected Data Transfer Length
+
+    /// Reserved for future usage, always MUST be 0.
+    uint8_t reserved;
+
+    /// Bidirectional Read Expected Data Transfer Length.
+    uint32_t bidi_read_exp_xfer_len;
 } iscsi_bidi_read_exp_xfer_ahs_packet;
 
-/* Certain iSCSI conditions result in the command being terminated at
-   the target (response code of Command Completed at Target) with a SCSI
-   CHECK CONDITION Status as outlined in the following definitions
-   (Sense key: Aborted Command 0x0B):
-*/
-#define ISCSI_DS_ERROR_UNEXPECTED_UNSOLICITED_DATA_ASC  0x0C // Unexpected unsolicited data
+
+/**
+ * @brief DataSegment Error: Unexpected unsolicited data.
+ *
+ * Certain iSCSI conditions result in the command being terminated at
+ * the target (response code of Command Completed at Target) with a SCSI
+ * CHECK CONDITION Status as outlined in the following definitions
+ * (Sense key: Aborted Command 0x0B).
+ */
+#define ISCSI_DS_ERROR_UNEXPECTED_UNSOLICITED_DATA_ASC  0x0C
+
+/**
+ * @brief DataSegment Error: Unexpected unsolicited data.
+ *
+ * Certain iSCSI conditions result in the command being terminated at
+ * the target (response code of Command Completed at Target) with a SCSI
+ * CHECK CONDITION Status as outlined in the following definitions
+ * (Sense key: Aborted Command 0x0B).
+ */
 #define ISCSI_DS_ERROR_UNEXPECTED_UNSOLICITED_DATA_ASCQ 0x0C
 
-#define ISCSI_DS_ERROR_INCORRECT_AMOUNT_OF_DATA_ASC  0x0C // Incorrect amount of data
+
+/**
+ * @brief DataSegment Error: Incorrect amount of data.
+ *
+ * Certain iSCSI conditions result in the command being terminated at
+ * the target (response code of Command Completed at Target) with a SCSI
+ * CHECK CONDITION Status as outlined in the following definitions
+ * (Sense key: Aborted Command 0x0B).
+ */
+#define ISCSI_DS_ERROR_INCORRECT_AMOUNT_OF_DATA_ASC  0x0C
+
+/**
+ * @brief DataSegment Error: Incorrect amount of data.
+ *
+ * Certain iSCSI conditions result in the command being terminated at
+ * the target (response code of Command Completed at Target) with a SCSI
+ * CHECK CONDITION Status as outlined in the following definitions
+ * (Sense key: Aborted Command 0x0B).
+ */
 #define ISCSI_DS_ERROR_INCORRECT_AMOUNT_OF_DATA_ASCQ 0x0D
 
-#define ISCSI_DS_ERROR_PROTOCOL_SERVICE_CRC_ERROR_ASC  0x47 // Protocol Service CRC error
+
+/**
+ * @brief DataSegment Error: Protocol Service CRC error.
+ *
+ * Certain iSCSI conditions result in the command being terminated at
+ * the target (response code of Command Completed at Target) with a SCSI
+ * CHECK CONDITION Status as outlined in the following definitions
+ * (Sense key: Aborted Command 0x0B).
+ */
+#define ISCSI_DS_ERROR_PROTOCOL_SERVICE_CRC_ERROR_ASC  0x47
+
+/**
+ * @brief DataSegment Error: Protocol Service CRC error.
+ *
+ * Certain iSCSI conditions result in the command being terminated at
+ * the target (response code of Command Completed at Target) with a SCSI
+ * CHECK CONDITION Status as outlined in the following definitions
+ * (Sense key: Aborted Command 0x0B).
+ */
 #define ISCSI_DS_ERROR_PROTOCOL_SERVICE_CRC_ERROR_ASCQ 0x05
 
-#define ISCSI_DS_ERROR_SNACK_REJECTED_ASC  0x11 // SNACK rejected
+
+/**
+ * @brief DataSegment Error: Selective Negative / Sequence Number Acknowledgment (SNACK) rejected.
+ *
+ * Certain iSCSI conditions result in the command being terminated at
+ * the target (response code of Command Completed at Target) with a SCSI
+ * CHECK CONDITION Status as outlined in the following definitions
+ * (Sense key: Aborted Command 0x0B).
+ */
+#define ISCSI_DS_ERROR_SNACK_REJECTED_ASC  0x11
+
+/**
+ * @brief DataSegment Error: Selective Negative / Sequence Number Acknowledgment (SNACK) rejected.
+ *
+ * Certain iSCSI conditions result in the command being terminated at
+ * the target (response code of Command Completed at Target) with a SCSI
+ * CHECK CONDITION Status as outlined in the following definitions
+ * (Sense key: Aborted Command 0x0B).
+ */
 #define ISCSI_DS_ERROR_SNACK_REJECTED_ASCQ 0x13
 
-/* Optional header and data digests protect the integrity of the header
-   and data, respectively.  The digests, if present, are located,
-   respectively, after the header and PDU-specific data and cover,
-   respectively, the header and the PDU data, each including the padding
-   bytes, if any.
 
-   The existence and type of digests are negotiated during the Login
-   Phase.
-*/
+/**
+ * @brief iSCSI header digest in case CRC32C has been negotiated.
+ *
+ * Optional header and data digests protect the integrity of the header
+ * and data, respectively. The digests, if present, are located,
+ * respectively, after the header and PDU-specific data and cover,
+ * respectively, the header and the PDU data, each including the padding
+ * bytes, if any.
+ *
+ * The existence and type of digests are negotiated during the Login
+ * Phase.
+ */
 typedef struct __attribute__((packed)) iscsi_header_digest {
-    uint32_t crc32c; // Header digest is a CRC32C for ensuring integrity
+    /// Header digest is a CRC32C for ensuring integrity.
+    uint32_t crc32c;
 } iscsi_header_digest;
 
+/**
+ * @brief iSCSI data digest in case CRC32C has been negotiated.
+ *
+ * Optional header and data digests protect the integrity of the header
+ * and data, respectively. The digests, if present, are located,
+ * respectively, after the header and PDU-specific data and cover,
+ * respectively, the header and the PDU data, each including the padding
+ * bytes, if any.
+ *
+ * The existence and type of digests are negotiated during the Login
+ * Phase.
+ */
 typedef struct __attribute__((packed)) iscsi_data_digest {
-    uint32_t crc32c; // Data digest is a CRC32C for ensuring integrity
+    /// Data digest is a CRC32C for ensuring integrity.
+    uint32_t crc32c;
 } iscsi_data_digest;
 
-/* iSCSI targets MUST support and enable Autosense. If Status is CHECK
-   CONDITION (0x02), then the data segment MUST contain sense data for
-   the failed command.
+/**
+ * @brief iSCSI DataSegment Command packet structure.
+ *
+ * iSCSI targets MUST support and enable Autosense. If Status is CHECK
+ * CONDITION (0x02), then the data segment MUST contain sense data for
+ * the failed command.
+ *
+ * For some iSCSI responses, the response data segment MAY contain some
+ * response-related information (e.g., for a target failure, it may
+ * contain a vendor-specific detailed description of the failure).
+ */
+typedef struct __attribute__((packed)) iscsi_ds_cmd_data {
+    /// SenseLength: This field indicates the length of Sense Data.
+    uint16_t len;
 
-   For some iSCSI responses, the response data segment MAY contain some
-   response-related information (e.g., for a target failure, it may
-   contain a vendor-specific detailed description of the failure).
-*/
+    /// The Sense Data contains detailed information about a CHECK CONDITION. SPC3 specifies the format and content of the Sense Data.
+    uint8_t sense_data[0];
 
-typedef struct __attribute__((packed)) iscsi_ds_cmd_data {
-    uint16_t len; // SenseLength - This field indicates the length of Sense Data.
-    uint8_t sense_data[0]; // The Sense Data contains detailed information about a CHECK CONDITION.
-                     // SPC3 specifies the format and content of the Sense Data.
-    uint8_t res_data[0]; // Response Data
+    /// Response Data.
+    uint8_t res_data[0];
 } iscsi_ds_cmd_data;
 
-// SCSI command opcodes (embedded in iSCSI protocol)
-#define SCSI_OPCODE_TESTUNITREADY          0x00 // TEST UNIT READY
-#define SCSI_OPCODE_READ6                  0x08 // READ(6)
-#define SCSI_OPCODE_INQUIRY                0x12 // INQUIRY
-#define SCSI_OPCODE_MODESELECT6            0x15 // MODE SELECT(6)
-#define SCSI_OPCODE_RESERVE6               0x16 // RESERVE(6)
-#define SCSI_OPCODE_RELEASE6               0x17 // RELEASE(6)
-#define SCSI_OPCODE_MODESENSE6             0x1A // MODE SENSE(6)
-#define SCSI_OPCODE_STARTSTOPUNIT          0x1B // START STOP UNIT
-#define SCSI_OPCODE_PREVENTALLOW           0x1E // PREVENT ALLOW MEDIUM REMOVAL
-#define SCSI_OPCODE_READCAPACITY10         0x25 // READ CAPACITY(10)
-#define SCSI_OPCODE_READ10                 0x28 // READ(10)
-#define SCSI_OPCODE_WRITE10                0x2A // WRITE(10)
-#define SCSI_OPCODE_WRITE_VERIFY10         0x2E // WRITE AND VERIFY(10)
-#define SCSI_OPCODE_VERIFY10               0x2F // VERIFY(10)
-#define SCSI_OPCODE_PREFETCH10             0x34 // PRE-FETCH(10)
-#define SCSI_OPCODE_SYNCHRONIZECACHE10     0x35 // SYNCHRONIZE CACHE(10)
-#define SCSI_OPCODE_READ_DEFECT_DATA10     0x37 // READ DEFECT DATA(10)
-#define SCSI_OPCODE_WRITE_SAME10           0x41 // WRITE SAME(10)
-#define SCSI_OPCODE_UNMAP                  0x42 // UNMAP
-#define SCSI_OPCODE_READTOC                0x43 // READ TOC/PMA/ATIP
-#define SCSI_OPCODE_SANITIZE               0x48 // SANITIZE
-#define SCSI_OPCODE_MODESELECT10           0x55 // MODE SELECT(10)
-#define SCSI_OPCODE_MODESENSE10            0x5A // MODE SENSE(10)
-#define SCSI_OPCODE_PERSISTENT_RESERVE_IN  0x5E // PERSISTENT RESERVE IN
-#define SCSI_OPCODE_PERSISTENT_RESERVE_OUT 0x5F // PERSISTENT RESERVE OUT
-#define SCSI_OPCODE_EXTENDED_COPY          0x83 // Third-party Copy OUT
-#define SCSI_OPCODE_RECEIVE_COPY_RESULTS   0x84 // Third-party Copy IN
-#define SCSI_OPCODE_READ16                 0x88 // READ(16)
-#define SCSI_OPCODE_COMPARE_AND_WRITE      0x89 // COMPARE AND WRITE
-#define SCSI_OPCODE_WRITE16                0x8A // WRITE(16)
-#define SCSI_OPCODE_ORWRITE                0x8B // ORWRITE
-#define SCSI_OPCODE_WRITE_VERIFY16         0x8E // WRITE AND VERIFY(16)
-#define SCSI_OPCODE_VERIFY16               0x8F // VERIFY(16)
-#define SCSI_OPCODE_PREFETCH16             0x90 // PRE-FETCH(16)
-#define SCSI_OPCODE_SYNCHRONIZECACHE16     0x91 // SYNCHRONIZE CACHE(16)
-#define SCSI_OPCODE_WRITE_SAME16           0x93 // WRITE SAME(16)
-#define SCSI_OPCODE_WRITE_ATOMIC16         0x9C // WRITE ATOMIC(16)
-#define SCSI_OPCODE_SERVICE_ACTION_IN      0x9E // SERVICE ACTION IN(16)
-#define SCSI_OPCODE_REPORTLUNS             0xA0 // REPORT LUNS
-#define SCSI_OPCODE_MAINTENANCE_IN         0xA3 // MAINTENANCE IN
-#define SCSI_OPCODE_READ12                 0xA8 // READ(12)
-#define SCSI_OPCODE_WRITE12                0xAA // WRITE(12)
-#define SCSI_OPCODE_WRITE_VERIFY12         0xAE // WRITE AND VERIFY(12)
-#define SCSI_OPCODE_VERIFY12               0xAF // VERIFY(12)
-#define SCSI_OPCODE_READ_DEFECT_DATA12     0xB7 // READ DEFECT DATA(12)
-
-#define ISCSI_SCSI_CMD_FLAGS_TASK_NO_UNSOLICITED_DATA   (1 << 7)   // (F) is set to 1 when no unsolicited SCSI Data-Out PDUs
-                                                                   // follow this PDU. When F = 1 for a write and if Expected
-                                                                   // Data Transfer Length is larger than the
-                                                                   // DataSegmentLength, the target may solicit additional data
-                                                                   // through R2T.
-#define ISCSI_SCSI_CMD_FLAGS_TASK_READ                  (1 << 6)   // (R) is set to 1 when the command is expected to input data
-#define ISCSI_SCSI_CMD_FLAGS_TASK_WRITE                 (1 << 5)   // (W) is set to 1 when the command is expected to output data
-
-#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_UNTAGGED         0x0         // Untagged task attribute
-#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_SIMPLE           0x1         // Simple task attribute
-#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_ORDERED          0x2         // Ordered task attribute
-#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_HEAD_QUEUE       0x3         // Head of queue task attribute
-#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_ACA              0x4         // ACA task attribute
-#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_RESERVED_1       0x5         // ACA task attribute
-#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_RESERVED_2       0x6         // ACA task attribute
-#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_RESERVED_3       0x7         // ACA task attribute
-
-/* Flags and Task Attributes:
-   At least one of the W and F bits MUST be set to 1.
-   Either or both of R and W MAY be 1 when the Expected Data Transfer
-   Length and/or the Bidirectional Read Expected Data Transfer Length
-   are 0, but they MUST NOT both be 0 when the Expected Data Transfer
-   Length and/or Bidirectional Read Expected Data Transfer Length are
-   not 0 (i.e., when some data transfer is expected, the transfer
-   direction is indicated by the R and/or W bit).
-*/
+/// SCSI command opcode (embedded in iSCSI protocol): TEST UNIT READY.
+#define ISCSI_SCSI_OPCODE_TESTUNITREADY          0x00
+
+/// SCSI command opcode (embedded in iSCSI protocol): READ(6).
+#define ISCSI_SCSI_OPCODE_READ6                  0x08
+
+/// SCSI command opcode (embedded in iSCSI protocol): INQUIRY.
+#define ISCSI_SCSI_OPCODE_INQUIRY                0x12
+
+/// SCSI command opcode (embedded in iSCSI protocol): MODE SELECT(6).
+#define ISCSI_SCSI_OPCODE_MODESELECT6            0x15
+
+/// SCSI command opcode (embedded in iSCSI protocol): RESERVE(6).
+#define ISCSI_SCSI_OPCODE_RESERVE6               0x16
+
+/// SCSI command opcode (embedded in iSCSI protocol): RELEASE(6).
+#define ISCSI_SCSI_OPCODE_RELEASE6               0x17
+
+/// SCSI command opcode (embedded in iSCSI protocol): MODE SENSE(6).
+#define ISCSI_SCSI_OPCODE_MODESENSE6             0x1A
+
+/// SCSI command opcode (embedded in iSCSI protocol): START STOP UNIT.
+#define ISCSI_SCSI_OPCODE_STARTSTOPUNIT          0x1B
+
+/// SCSI command opcode (embedded in iSCSI protocol): PREVENT ALLOW MEDIUM REMOVAL.
+#define ISCSI_SCSI_OPCODE_PREVENTALLOW           0x1E
+
+/// SCSI command opcode (embedded in iSCSI protocol): READ CAPACITY(10).
+#define ISCSI_SCSI_OPCODE_READCAPACITY10         0x25
+
+/// SCSI command opcode (embedded in iSCSI protocol): READ(10).
+#define ISCSI_SCSI_OPCODE_READ10                 0x28
+
+/// SCSI command opcode (embedded in iSCSI protocol): WRITE(10).
+#define ISCSI_SCSI_OPCODE_WRITE10                0x2A
+
+/// SCSI command opcode (embedded in iSCSI protocol): WRITE AND VERIFY(10).
+#define ISCSI_SCSI_OPCODE_WRITE_VERIFY10         0x2E
+
+/// SCSI command opcode (embedded in iSCSI protocol): VERIFY(10).
+#define ISCSI_SCSI_OPCODE_VERIFY10               0x2F
+
+/// SCSI command opcode (embedded in iSCSI protocol): PRE-FETCH(10).
+#define ISCSI_SCSI_OPCODE_PREFETCH10             0x34
+
+/// SCSI command opcode (embedded in iSCSI protocol): SYNCHRONIZE CACHE(10).
+#define ISCSI_SCSI_OPCODE_SYNCHRONIZECACHE10     0x35
+
+/// SCSI command opcode (embedded in iSCSI protocol): READ DEFECT DATA(10).
+#define ISCSI_SCSI_OPCODE_READ_DEFECT_DATA10     0x37
+
+/// SCSI command opcode (embedded in iSCSI protocol): WRITE SAME(10).
+#define ISCSI_SCSI_OPCODE_WRITE_SAME10           0x41
+
+/// SCSI command opcode (embedded in iSCSI protocol): UNMAP.
+#define ISCSI_SCSI_OPCODE_UNMAP                  0x42
+
+/// SCSI command opcode (embedded in iSCSI protocol): READ TOC/PMA/ATIP.
+#define ISCSI_SCSI_OPCODE_READTOC                0x43
+
+/// SCSI command opcode (embedded in iSCSI protocol): SANITIZE.
+#define ISCSI_SCSI_OPCODE_SANITIZE               0x48
+
+/// SCSI command opcode (embedded in iSCSI protocol): MODE SELECT(10).
+#define ISCSI_SCSI_OPCODE_MODESELECT10           0x55
+
+/// SCSI command opcode (embedded in iSCSI protocol): MODE SENSE(10).
+#define ISCSI_SCSI_OPCODE_MODESENSE10            0x5A
+
+/// SCSI command opcode (embedded in iSCSI protocol): PERSISTENT RESERVE IN.
+#define ISCSI_SCSI_OPCODE_PERSISTENT_RESERVE_IN  0x5E
+
+/// SCSI command opcode (embedded in iSCSI protocol): PERSISTENT RESERVE OUT.
+#define ISCSI_SCSI_OPCODE_PERSISTENT_RESERVE_OUT 0x5F
 
-#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_MASK             0x7         // Task Attributes (ATTR) are encoded in the first three LSBs'
+/// SCSI command opcode (embedded in iSCSI protocol): Third-party Copy OUT.
+#define ISCSI_SCSI_OPCODE_EXTENDED_COPY          0x83
 
+/// SCSI command opcode (embedded in iSCSI protocol): Third-party Copy IN.
+#define ISCSI_SCSI_OPCODE_RECEIVE_COPY_RESULTS   0x84
+
+/// SCSI command opcode (embedded in iSCSI protocol): READ(16).
+#define ISCSI_SCSI_OPCODE_READ16                 0x88
+
+/// SCSI command opcode (embedded in iSCSI protocol): COMPARE AND WRITE.
+#define ISCSI_SCSI_OPCODE_COMPARE_AND_WRITE      0x89
+
+/// SCSI command opcode (embedded in iSCSI protocol): WRITE(16).
+#define ISCSI_SCSI_OPCODE_WRITE16                0x8A
+
+/// SCSI command opcode (embedded in iSCSI protocol): ORWRITE.
+#define ISCSI_SCSI_OPCODE_ORWRITE                0x8B
+
+/// SCSI command opcode (embedded in iSCSI protocol): WRITE AND VERIFY(16).
+#define ISCSI_SCSI_OPCODE_WRITE_VERIFY16         0x8E
+
+/// SCSI command opcode (embedded in iSCSI protocol): VERIFY(16).
+#define ISCSI_SCSI_OPCODE_VERIFY16               0x8F
+
+/// SCSI command opcode (embedded in iSCSI protocol): PRE-FETCH(16).
+#define ISCSI_SCSI_OPCODE_PREFETCH16             0x90
+
+/// SCSI command opcode (embedded in iSCSI protocol): SYNCHRONIZE CACHE(16).
+#define ISCSI_SCSI_OPCODE_SYNCHRONIZECACHE16     0x91
+
+/// SCSI command opcode (embedded in iSCSI protocol): WRITE SAME(16).
+#define ISCSI_SCSI_OPCODE_WRITE_SAME16           0x93
+
+/// SCSI command opcode (embedded in iSCSI protocol): WRITE ATOMIC(16).
+#define ISCSI_SCSI_OPCODE_WRITE_ATOMIC16         0x9C
+
+/// SCSI command opcode (embedded in iSCSI protocol): SERVICE ACTION IN(16).
+#define ISCSI_SCSI_OPCODE_SERVICE_ACTION_IN      0x9E
+
+/// SCSI command opcode (embedded in iSCSI protocol): REPORT LUNS.
+#define ISCSI_SCSI_OPCODE_REPORTLUNS             0xA0
+
+/// SCSI command opcode (embedded in iSCSI protocol): MAINTENANCE IN.
+#define ISCSI_SCSI_OPCODE_MAINTENANCE_IN         0xA3
+
+/// SCSI command opcode (embedded in iSCSI protocol): READ(12).
+#define ISCSI_SCSI_OPCODE_READ12                 0xA8
+
+/// SCSI command opcode (embedded in iSCSI protocol): WRITE(12).
+#define ISCSI_SCSI_OPCODE_WRITE12                0xAA
+
+/// SCSI command opcode (embedded in iSCSI protocol): WRITE AND VERIFY(12).
+#define ISCSI_SCSI_OPCODE_WRITE_VERIFY12         0xAE
+
+/// SCSI command opcode (embedded in iSCSI protocol): VERIFY(12).
+#define ISCSI_SCSI_OPCODE_VERIFY12               0xAF
+
+/// SCSI command opcode (embedded in iSCSI protocol): READ DEFECT DATA(12).
+#define ISCSI_SCSI_OPCODE_READ_DEFECT_DATA12     0xB7
+
+
+/**
+ * @brief iSCSI SCSI command flags: No unsolicited data.
+ *
+ * (F) is set to 1 when no unsolicited SCSI Data-Out PDUs
+ * follow this PDU. When F = 1 for a write and if Expected
+ * Data Transfer Length is larger than the
+ * DataSegmentLength, the target may solicit additional data
+ * through R2T.
+ */
+#define ISCSI_SCSI_CMD_FLAGS_TASK_NO_UNSOLICITED_DATA   (1 << 7)
+
+/**
+ * @brief iSCSI SCSI command flags: Expected input data.
+ *
+ * (R) is set to 1 when the command is expected to input data.
+ */
+#define ISCSI_SCSI_CMD_FLAGS_TASK_READ                  (1 << 6)
+
+/**
+ * @brief iSCSI SCSI command flags: Expected output data.
+ *
+ * (W) is set to 1 when the command is expected to output data.
+ */
+#define ISCSI_SCSI_CMD_FLAGS_TASK_WRITE                 (1 << 5)
+
+
+/// SCSI command flags task attribute: Untagged.
+#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_UNTAGGED         0x0
+
+/// SCSI command flags task attribute: Simple.
+#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_SIMPLE           0x1
+
+/// SCSI command flags task attribute: Ordered.
+#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_ORDERED          0x2
+
+/// SCSI command flags task attribute: Head of queue.
+#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_HEAD_QUEUE       0x3
+
+/// SCSI command flags task attribute: ACA.
+#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_ACA              0x4
+
+/// SCSI command flags task attribute: Reserved.
+#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_RESERVED_1       0x5
+
+/// SCSI command flags task attribute: Reserved.
+#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_RESERVED_2       0x6
+
+/// SCSI command flags task attribute: Reserved.
+#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_RESERVED_3       0x7
+
+/// SCSI command flags Task Attributes (ATTR) are encoded in the first three LSBs.
+#define ISCSI_SCSI_CMD_FLAGS_TASK_ATTR_MASK             0x7
+
+
+/**
+ * @brief iSCSI Flag and Task Attributes for SCSI command packet data.
+ *
+ * Flags and Task Attributes:
+ * At least one of the W and F bits MUST be set to 1.\n
+ * Either or both of R and W MAY be 1 when the Expected Data Transfer
+ * Length and/or the Bidirectional Read Expected Data Transfer Length
+ * are 0, but they MUST NOT both be 0 when the Expected Data Transfer
+ * Length and/or Bidirectional Read Expected Data Transfer Length are
+ * not 0 (i.e., when some data transfer is expected, the transfer
+ * direction is indicated by the R and/or W bit).
+ */
 typedef struct __attribute__((packed)) iscsi_scsi_cmd_packet {
-    uint8_t opcode; // Always 0x01 according to specification (see above)
-    int8_t flags_task; // Flags and Task Attributes
-    uint16_t reserved; // Reserved for future usage
-    uint8_t total_ahs_len; // Total AHS length
-    uint8_t ds_len[3]; // Data segment length
-    uint64_t lun; // LUN bitmask
-    uint32_t init_task_tag; // Initiator task tag
-    uint32_t exp_xfer_len; // Expected Data Transfer Length
-                           // For unidirectional operations, the Expected Data Transfer Length
-                           // field contains the number of bytes of data involved in this SCSI
-                           // operation. For a unidirectional write operation (W flag set to 1 and
-                           // R flag set to 0), the initiator uses this field to specify the number
-                           // of bytes of data it expects to transfer for this operation. For a
-                           // unidirectional read operation (W flag set to 0 and R flag set to 1),
-                           // the initiator uses this field to specify the number of bytes of data
-                           // it expects the target to transfer to the initiator. It corresponds
-                           // to the SAM-2 byte count.
-                           // For bidirectional operations (both R and W flags are set to 1), this
-                           // field contains the number of data bytes involved in the write
-                           // transfer. For bidirectional operations, an additional header segment
-                           // MUST be present in the header sequence that indicates the
-                           // Bidirectional Read Expected Data Transfer Length. The Expected Data
-                           // Transfer Length field and the Bidirectional Read Expected Data
-                           // Transfer Length field correspond to the SAM-2 byte count.
-                           // If the Expected Data Transfer Length for a write and the length of
-                           // the immediate data part that follows the command (if any) are the
-                           // same, then no more data PDUs are expected to follow. In this case,
-                           // the F bit MUST be set to 1.
-                           // If the Expected Data Transfer Length is higher than the
-                           // FirstBurstLength (the negotiated maximum amount of unsolicited data
-                           // the target will accept), the initiator MUST send the maximum amount
-                           // of unsolicited data OR ONLY the immediate data, if any.
-                           // Upon completion of a data transfer, the target informs the initiator
-                           // (through residual counts) of how many bytes were actually processed
-                           // (sent and/or received) by the target.
-    uint32_t cmd_sn; // The CmdSN enables ordered delivery across multiple connections in a single session
-    uint32_t exp_stat_sn; // Command responses up to ExpStatSN - 1 (modulo 2**32) have been
-                          // received (acknowledges status) on the connection.
-    struct iscsi_cdb scsi_cdb; // SCSI Command Descriptor Block (CDB)
-                               // There are 16 bytes in the CDB field to accommodate the commonly used
-                               // CDBs. Whenever the CDB is larger than 16 bytes, an Extended CDB AHS
-                               // MUST be used to contain the CDB spillover.
-    struct iscsi_ahs_packet ahs; // Optional AHS packet data
-    struct iscsi_header_digest hdr_digest; // Optional header digest
-    struct iscsi_ds_cmd_data ds_cmd_data; // Optional data segment, command data
-    struct iscsi_data_digest data_digest; // Optional data digest
+    /// Always 1 according to the iSCSI specification.
+    uint8_t opcode;
+
+    /// Flags and Task Attributes.
+    int8_t flags_task;
+
+    /// Reserved for future usage, MUST always be 0.
+    uint16_t reserved;
+
+    /// Total length of AHS.
+    uint8_t total_ahs_len;
+
+    /// Length of DataSegment.
+    uint8_t ds_len[3];
+
+    /// SCSI LUN bit mask.
+    uint64_t lun;
+
+    /// Initiator Task Tag (ITT).
+    uint32_t init_task_tag;
+
+    /**
+     * @brief Expected Data Transfer Length.
+     *
+     * For unidirectional operations, the Expected Data Transfer Length
+     * field contains the number of bytes of data involved in this SCSI
+     * operation. For a unidirectional write operation (W flag set to 1 and
+     * R flag set to 0), the initiator uses this field to specify the number
+     * of bytes of data it expects to transfer for this operation. For a
+     * unidirectional read operation (W flag set to 0 and R flag set to 1),
+     * the initiator uses this field to specify the number of bytes of data
+     * it expects the target to transfer to the initiator. It corresponds
+     * to the SAM-2 byte count.\n
+     * For bidirectional operations (both R and W flags are set to 1), this
+     * field contains the number of data bytes involved in the write
+     * transfer. For bidirectional operations, an additional header segment
+     * MUST be present in the header sequence that indicates the
+     * Bidirectional Read Expected Data Transfer Length. The Expected Data
+     * Transfer Length field and the Bidirectional Read Expected Data
+     * Transfer Length field correspond to the SAM-2 byte count.
+     * If the Expected Data Transfer Length for a write and the length of
+     * the immediate data part that follows the command (if any) are the
+     * same, then no more data PDUs are expected to follow. In this case,
+     * the F bit MUST be set to 1.\n
+     * If the Expected Data Transfer Length is higher than the
+     * FirstBurstLength (the negotiated maximum amount of unsolicited data
+     * the target will accept), the initiator MUST send the maximum amount
+     * of unsolicited data OR ONLY the immediate data, if any.
+     * Upon completion of a data transfer, the target informs the initiator
+     * (through residual counts) of how many bytes were actually processed
+     * (sent and/or received) by the target.
+     */
+    uint32_t exp_xfer_len;
+
+    /// The CmdSN enables ordered delivery across multiple connections in a single session.
+    uint32_t cmd_sn;
+
+    /// Command responses up to ExpStatSN - 1 (modulo 2**32) have been received (acknowledges status) on the connection.
+    uint32_t exp_stat_sn;
+
+    /**
+     * @brief SCSI Command Descriptor Block (CDB).
+     *
+     * There are 16 bytes in the CDB field to accommodate the commonly used
+     * CDBs. Whenever the CDB is larger than 16 bytes, an Extended CDB AHS
+     * MUST be used to contain the CDB spillover.
+     */
+    iscsi_cdb scsi_cdb;
+
+    /// Optional AHS packet data.
+    iscsi_ahs_packet ahs;
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
+
+    /// Optional data segment, command data.
+    iscsi_ds_cmd_data ds_cmd_data;
+
+    /// Optional data digest.
+    iscsi_data_digest data_digest;
 } iscsi_scsi_cmd_packet;
 
-#define ISCSI_SCSI_RESPONSE_FLAGS_RES_UNDERFLOW   (1 << 1)           // (U) set for Residual Underflow. In this case, the Residual
-                                                                     // Count indicates the number of bytes that were not
-                                                                     // transferred out of the number of bytes that were expected
-                                                                     // to be transferred. For a bidirectional operation, the
-                                                                     // Residual Count contains the residual for the write
-                                                                     // operation.
-
-#define ISCSI_SCSI_RESPONSE_FLAGS_RES_OVERFLOW    (1 << 2)           // (O) set for Residual Overflow. In this case, the Residual
-                                                                     // Count indicates the number of bytes that were not
-                                                                     // transferred because the initiator's Expected Data
-                                                                     // Transfer Length was not sufficient. For a bidirectional
-                                                                     // operation, the Residual Count contains the residual for
-                                                                     // the write operation.
-
-#define ISCSI_SCSI_RESPONSE_FLAGS_BIDI_READ_RES_UNDERFLOW   (1 << 3) // (u) set for Bidirectional Read Residual Underflow. In this
-                                                                     // case, the Bidirectional Read Residual Count indicates the
-                                                                     // number of bytes that were not transferred to the
-                                                                     // initiator out of the number of bytes expected to be
-                                                                     // transferred.
-
-#define ISCSI_SCSI_RESPONSE_FLAGS_BIDI_READ_RES_OVERFLOW    (1 << 4) // (o) set for Bidirectional Read Residual Overflow. In this
-                                                                     // case, the Bidirectional Read Residual Count indicates the
-                                                                     // number of bytes that were not transferred to the
-                                                                     // initiator because the initiator's Bidirectional Read
-                                                                     // Expected Data Transfer Length was not sufficient.
-
-/* Bits O and U and bits o and u are mutually exclusive (i.e., having
-   both o and u or O and U set to 1 is a protocol error).
-
-   For a response other than "Command Completed at Target", bits 3-6
-   MUST be 0.
-*/
 
-#define ISCSI_SCSI_RESPONSE_STATUS_GOOD             0x00
-#define ISCSI_SCSI_RESPONSE_STATUS_CHECK_COND       0x02
-#define ISCSI_SCSI_RESPONSE_STATUS_BUSY             0x08
-#define ISCSI_SCSI_RESPONSE_STATUS_RES_CONFLICT     0x18
-#define ISCSI_SCSI_RESPONSE_STATUS_TASK_SET_FULL    0x28
-#define ISCSI_SCSI_RESPONSE_STATUS_ACA_ACTIVE       0x30
-#define ISCSI_SCSI_RESPONSE_STATUS_TASK_ABORTED     0x40
-
-/* The Status field is used to report the SCSI status of the command (as
-   specified in SAM2) and is only valid if the response code is
-   Command Completed at Target.
-
-   If a SCSI device error is detected while data from the initiator is
-   still expected (the command PDU did not contain all the data and the
-   target has not received a data PDU with the Final bit set), the
-   target MUST wait until it receives a data PDU with the F bit set in
-   the last expected sequence before sending the Response PDU.
-*/
+/**
+ * @brief SCSI response flags: Residual Underflow.
+ *
+ * (U) set for Residual Underflow. In this case, the Residual
+ * Count indicates the number of bytes that were not
+ * transferred out of the number of bytes that were expected
+ * to be transferred. For a bidirectional operation, the
+ * Residual Count contains the residual for the write
+ * operation.
+ *
+ * Bits O and U and bits o and u are mutually exclusive (i.e., having
+ * both o and u or O and U set to 1 is a protocol error).
+ *
+ * For a response other than "Command Completed at Target", bits 3-6
+ * MUST be 0.
+ */
+#define ISCSI_SCSI_RESPONSE_FLAGS_RES_UNDERFLOW   (1 << 1)
+
+/**
+ * @brief SCSI response flags: Residual Overflow.
+ *
+ * (O) set for Residual Overflow. In this case, the Residual
+ * Count indicates the number of bytes that were not
+ * transferred because the initiator's Expected Data
+ * Transfer Length was not sufficient. For a bidirectional
+ * operation, the Residual Count contains the residual for
+ * the write operation.
+ *
+ * Bits O and U and bits o and u are mutually exclusive (i.e., having
+ * both o and u or O and U set to 1 is a protocol error).
+ *
+ * For a response other than "Command Completed at Target", bits 3-6
+ * MUST be 0.
+ */
+#define ISCSI_SCSI_RESPONSE_FLAGS_RES_OVERFLOW    (1 << 2)
 
-#define ISCSI_SCSI_RESPONSE_CODE_OK                 0x00 // Command Completed at Target
-#define ISCSI_SCSI_RESPONSE_CODE_FAIL               0x01 // Target Failure
-#define ISCSI_SCSI_RESPONSE_CODE_VENDOR_FIRST       0x80 // First vendor specific response code
-#define ISCSI_SCSI_RESPONSE_CODE_VENDOR_LAST        0xFF // Last vendor specific response code
+/**
+ * @brief SCSI response flags: Bidirectional Read Residual Underflow.
+ *
+ * (u) set for Bidirectional Read Residual Underflow. In this
+ * case, the Bidirectional Read Residual Count indicates the
+ * number of bytes that were not transferred to the
+ * initiator out of the number of bytes expected to be
+ * transferred.
+ *
+ * Bits O and U and bits o and u are mutually exclusive (i.e., having
+ * both o and u or O and U set to 1 is a protocol error).
+ *
+ * For a response other than "Command Completed at Target", bits 3-6
+ * MUST be 0.
+ */
+#define ISCSI_SCSI_RESPONSE_FLAGS_BIDI_READ_RES_UNDERFLOW   (1 << 3)
 
-/* The Response field is used to report a service response. The mapping
-   of the response code into a SCSI service response code value, if
-   needed, is outside the scope of this document. However, in symbolic
-   terms, response value 0x00 maps to the SCSI service response (see
-*/
+/**
+ * @brief SCSI response flags: Bidirectional Read Residual Overflow.
+ *
+ + (o) set for Bidirectional Read Residual Overflow. In this
+ * case, the Bidirectional Read Residual Count indicates the
+ * number of bytes that were not transferred to the
+ * initiator because the initiator's Bidirectional Read
+ * Expected Data Transfer Length was not sufficient.
+ *
+ * Bits O and U and bits o and u are mutually exclusive (i.e., having
+ * both o and u or O and U set to 1 is a protocol error).
+ *
+ * For a response other than "Command Completed at Target", bits 3-6
+ * MUST be 0.
+ */
+#define ISCSI_SCSI_RESPONSE_FLAGS_BIDI_READ_RES_OVERFLOW    (1 << 4)
+
+/**
+ * @brief SCSI status response code: Good.
+ *
+ * The Status field is used to report the SCSI status of the command (as
+ * specified in SAM2) and is only valid if the response code is
+ * Command Completed at Target.
+ *
+ * If a SCSI device error is detected while data from the initiator is
+ * still expected (the command PDU did not contain all the data and the
+ * target has not received a data PDU with the Final bit set), the
+ * target MUST wait until it receives a data PDU with the F bit set in
+ * the last expected sequence before sending the Response PDU.
+ */
+#define ISCSI_SCSI_RESPONSE_STATUS_GOOD          0x00
+
+/**
+ * @brief SCSI status response code: Check condition.
+ *
+ * The Status field is used to report the SCSI status of the command (as
+ * specified in SAM2) and is only valid if the response code is
+ * Command Completed at Target.
+ *
+ * If a SCSI device error is detected while data from the initiator is
+ * still expected (the command PDU did not contain all the data and the
+ * target has not received a data PDU with the Final bit set), the
+ * target MUST wait until it receives a data PDU with the F bit set in
+ * the last expected sequence before sending the Response PDU.
+ */
+#define ISCSI_SCSI_RESPONSE_STATUS_CHECK_COND    0x02
+
+/**
+ * @brief SCSI status response code: Busy.
+ *
+ * The Status field is used to report the SCSI status of the command (as
+ * specified in SAM2) and is only valid if the response code is
+ * Command Completed at Target.
+ *
+ * If a SCSI device error is detected while data from the initiator is
+ * still expected (the command PDU did not contain all the data and the
+ * target has not received a data PDU with the Final bit set), the
+ * target MUST wait until it receives a data PDU with the F bit set in
+ * the last expected sequence before sending the Response PDU.
+ */
+#define ISCSI_SCSI_RESPONSE_STATUS_BUSY          0x08
+
+/**
+ * @brief SCSI status response code: Residual conflict.
+ *
+ * The Status field is used to report the SCSI status of the command (as
+ * specified in SAM2) and is only valid if the response code is
+ * Command Completed at Target.
+ *
+ * If a SCSI device error is detected while data from the initiator is
+ * still expected (the command PDU did not contain all the data and the
+ * target has not received a data PDU with the Final bit set), the
+ * target MUST wait until it receives a data PDU with the F bit set in
+ * the last expected sequence before sending the Response PDU.
+ */
+#define ISCSI_SCSI_RESPONSE_STATUS_RES_CONFLICT  0x18
+
+/**
+ * @brief SCSI status response code: Task set full.
+ *
+ * The Status field is used to report the SCSI status of the command (as
+ * specified in SAM2) and is only valid if the response code is
+ * Command Completed at Target.
+ *
+ * If a SCSI device error is detected while data from the initiator is
+ * still expected (the command PDU did not contain all the data and the
+ * target has not received a data PDU with the Final bit set), the
+ * target MUST wait until it receives a data PDU with the F bit set in
+ * the last expected sequence before sending the Response PDU.
+ */
+#define ISCSI_SCSI_RESPONSE_STATUS_TASK_SET_FULL 0x28
+
+/**
+ * @brief SCSI status response code: ACA active.
+ *
+ * The Status field is used to report the SCSI status of the command (as
+ * specified in SAM2) and is only valid if the response code is
+ * Command Completed at Target.
+ *
+ * If a SCSI device error is detected while data from the initiator is
+ * still expected (the command PDU did not contain all the data and the
+ * target has not received a data PDU with the Final bit set), the
+ * target MUST wait until it receives a data PDU with the F bit set in
+ * the last expected sequence before sending the Response PDU.
+ */
+#define ISCSI_SCSI_RESPONSE_STATUS_ACA_ACTIVE    0x30
+
+/**
+ * @brief SCSI status response code: Task aborted.
+ *
+ * The Status field is used to report the SCSI status of the command (as
+ * specified in SAM2) and is only valid if the response code is
+ * Command Completed at Target.
+ *
+ * If a SCSI device error is detected while data from the initiator is
+ * still expected (the command PDU did not contain all the data and the
+ * target has not received a data PDU with the Final bit set), the
+ * target MUST wait until it receives a data PDU with the F bit set in
+ * the last expected sequence before sending the Response PDU.
+ */
+#define ISCSI_SCSI_RESPONSE_STATUS_TASK_ABORTED  0x40
+
+/// SCSI response code: Command Completed at Target.
+#define ISCSI_SCSI_RESPONSE_CODE_OK              0x00
+
+/// SCSI response code: Target Failure.
+#define ISCSI_SCSI_RESPONSE_CODE_FAIL            0x01
+
+/// SCSI response code: First vendor specific response code.
+#define ISCSI_SCSI_RESPONSE_CODE_VENDOR_FIRST    0x80
+
+/// SCSI response code: Last vendor specific response code.
+#define ISCSI_SCSI_RESPONSE_CODE_VENDOR_LAST     0xFF
+
+/**
+ * @brief iSCSI SCSI command response packet data.
+ *
+ * The Response field is used to report a service response. The mapping
+ * of the response code into a SCSI service response code value, if
+ * needed, is outside the scope of this document. However, in symbolic
+ * terms, response value 0x00 maps to the SCSI service response (see
+ */
 typedef struct __attribute__((packed)) iscsi_scsi_response_packet {
-    uint8_t opcode; // Always 0x21 according to specification (see above)
-    int8_t flags; // Flags (see above)
-    uint8_t response; // This field contains the iSCSI service response.
-    uint8_t status; // The Status field is used to report the SCSI status of the command (as
-                    // specified in SAM2) and is only valid if the response code is
-                    // Command Completed at Target. See above for codes.
-    uint8_t total_ahs_len; // Total AHS length
-    uint8_t ds_len[3]; // Data segment length
-    uint64_t reserved; // Reserved for future usage
-    uint32_t init_task_tag; // Initiator task tag
-    uint32_t snack_tag; // This field contains a copy of the SNACK Tag of the last SNACK Tag
-                        // accepted by the target on the same connection and for the command for
-                        // which the response is issued. Otherwise, it is reserved and should
-                        // be set to 0.
-                        // After issuing a R-Data SNACK, the initiator must discard any SCSI
-                        // status unless contained in a SCSI Response PDU carrying the same
-                        // SNACK Tag as the last issued R-Data SNACK for the SCSI command on the
-                        // current connection.
-    uint32_t stat_sn; // StatSN - Status Sequence Number
-                      // The StatSN is a sequence number that the target iSCSI layer generates
-                      // per connection and that in turn enables the initiator to acknowledge
-                      // status reception. The StatSN is incremented by 1 for every
-                      // response/status sent on a connection, except for responses sent as a
-                      // result of a retry or SNACK. In the case of responses sent due to a
-                      // retransmission request, the StatSN MUST be the same as the first time
-                      // the PDU was sent, unless the connection has since been restarted.
-    uint32_t exp_cmd_sn; // ExpCmdSN - Next Expected CmdSN from This Initiator
-                         // The ExpCmdSN is a sequence number that the target iSCSI returns to
-                         // the initiator to acknowledge command reception. It is used to update
-                         // a local variable with the same name. An ExpCmdSN equal to
-                         // MaxCmdSN + 1 indicates that the target cannot accept new commands.
-    uint32_t max_cmd_sn; // MaxCmdSN - Maximum CmdSN from This Initiator
-                         // The MaxCmdSN is a sequence number that the target iSCSI returns to
-                         // the initiator to indicate the maximum CmdSN the initiator can send.
-                         // It is used to update a local variable with the same name. If the
-                         // MaxCmdSN is equal to ExpCmdSN - 1, this indicates to the initiator
-                         // that the target cannot receive any additional commands. When the
-                         // MaxCmdSN changes at the target while the target has no pending PDUs
-                         // to convey this information to the initiator, it MUST generate a
-                         // NOP-In to carry the new MaxCmdSN.
-    uint32_t exp_data_sn; // ExpDataSN or Reserved
-                          // This field indicates the number of Data-In (read) PDUs the target has
-                          // sent for the command.
-                          // This field MUST be 0 if the response code is not Command Completed at
-                          // Target or the target sent no Data-In PDUs for the command.
-    uint32_t bidi_read_res_cnt; // Bidirectional Read Residual Count or Reserved
-                                // The Bidirectional Read Residual Count field MUST be valid in the case
-                                // where either the u bit or the o bit is set. If neither bit is set,
-                                // the Bidirectional Read Residual Count field is reserved. Targets may
-                                // set the Bidirectional Read Residual Count, and initiators may use it
-                                // when the response code is Command Completed at Target. If the o bit
-                                // is set, the Bidirectional Read Residual Count indicates the number of
-                                // bytes that were not transferred to the initiator because the
-                                // initiator's Bidirectional Read Expected Data Transfer Length was not
-                                // sufficient. If the u bit is set, the Bidirectional Read Residual
-                                // Count indicates the number of bytes that were not transferred to the
-                                // initiator out of the number of bytes expected to be transferred.
-    uint32_t res_cnt; // Residual Count or Reserved
-                      // The Residual Count field MUST be valid in the case where either the U
-                      // bit or the O bit is set. If neither bit is set, the Residual Count
-                      // field MUST be ignored on reception and SHOULD be set to 0 when
-                      // sending. Targets may set the residual count, and initiators may use
-                      // it when the response code is Command Completed at Target (even if the
-                      // status returned is not GOOD). If the O bit is set, the Residual
-                      // Count indicates the number of bytes that were not transferred because
-                      // the initiator's Expected Data Transfer Length was not sufficient. If
-                      // the U bit is set, the Residual Count indicates the number of bytes
-                      // that were not transferred out of the number of bytes expected to be
-                      // transferred.
-    struct iscsi_header_digest hdr_digest; // Optional header digest
-    struct iscsi_ds_cmd_data ds_cmd_data; // Optional data segment, command data
-    struct iscsi_data_digest data_digest; // Optional data digest
+    /// Always 0x21 according to specification.
+    uint8_t opcode;
+
+    /// Flags.
+    int8_t flags;
+
+    /// This field contains the iSCSI service response.
+    uint8_t response;
+
+    /// The Status field is used to report the SCSI status of the command (as specified in SAM2) and is only valid if the response code is Command Completed at Target.
+    uint8_t status;
+
+    /// Total AHS length.
+    uint8_t total_ahs_len;
+
+    /// Data segment length.
+    uint8_t ds_len[3];
+
+    /// Reserved for future usage. Always MUST be 0.
+    uint64_t reserved;
+
+    /// Initiator Task Tag (ITT).
+    uint32_t init_task_tag;
+
+    /**
+     * @brief Copy of the last accepted Selective Negative / Sequence Number Acknowledgment (SNACK) tag.
+     *
+     * This field contains a copy of the SNACK Tag of the last SNACK Tag
+     * accepted by the target on the same connection and for the command for
+     * which the response is issued. Otherwise, it is reserved and should
+     * be set to 0.\n
+     * After issuing a R-Data SNACK, the initiator must discard any SCSI
+     * status unless contained in a SCSI Response PDU carrying the same
+     * SNACK Tag as the last issued R-Data SNACK for the SCSI command on the
+     * current connection.
+     */
+    uint32_t snack_tag;
+
+    /**
+     * @brief StatSN - Status Sequence Number.
+     *
+     * The StatSN is a sequence number that the target iSCSI layer generates
+     * per connection and that in turn enables the initiator to acknowledge
+     * status reception. The StatSN is incremented by 1 for every
+     * response/status sent on a connection, except for responses sent as a
+     * result of a retry or SNACK. In the case of responses sent due to a
+     * retransmission request, the StatSN MUST be the same as the first time
+     * the PDU was sent, unless the connection has since been restarted.
+     */
+    uint32_t stat_sn;
+
+    /**
+     * @brief ExpCmdSN - Next Expected CmdSN from This Initiator.
+     *
+     * The ExpCmdSN is a sequence number that the target iSCSI returns to
+     * the initiator to acknowledge command reception. It is used to update
+     * a local variable with the same name. An ExpCmdSN equal to
+     * MaxCmdSN + 1 indicates that the target cannot accept new commands.
+     */
+    uint32_t exp_cmd_sn;
+
+    /**
+     * @brief MaxCmdSN - Maximum CmdSN from This Initiator.
+     *
+     * The MaxCmdSN is a sequence number that the target iSCSI returns to
+     * the initiator to indicate the maximum CmdSN the initiator can send.
+     * It is used to update a local variable with the same name. If the
+     * MaxCmdSN is equal to ExpCmdSN - 1, this indicates to the initiator
+     * that the target cannot receive any additional commands. When the
+     * MaxCmdSN changes at the target while the target has no pending PDUs
+     * to convey this information to the initiator, it MUST generate a
+     * NOP-In to carry the new MaxCmdSN.
+     */
+    uint32_t max_cmd_sn;
+
+    /**
+     * @brief ExpDataSN or Reserved.
+     *
+     * This field indicates the number of Data-In (read) PDUs the target has
+     * sent for the command.\n
+     * This field MUST be 0 if the response code is not Command Completed at
+     * Target or the target sent no Data-In PDUs for the command.
+     */
+    uint32_t exp_data_sn;
+
+    /**
+     * @brief Bidirectional Read Residual Count or Reserved.
+     *
+     * The Bidirectional Read Residual Count field MUST be valid in the case
+     * where either the u bit or the o bit is set. If neither bit is set,
+     * the Bidirectional Read Residual Count field is reserved. Targets may
+     * set the Bidirectional Read Residual Count, and initiators may use it
+     * when the response code is Command Completed at Target. If the o bit
+     * is set, the Bidirectional Read Residual Count indicates the number of
+     * bytes that were not transferred to the initiator because the
+     * initiator's Bidirectional Read Expected Data Transfer Length was not
+     * sufficient. If the u bit is set, the Bidirectional Read Residual
+     * Count indicates the number of bytes that were not transferred to the
+     * initiator out of the number of bytes expected to be transferred.
+     */
+    uint32_t bidi_read_res_cnt;
+
+    /**
+     * @brief Residual Count or Reserved.
+     *
+     * The Residual Count field MUST be valid in the case where either the U
+     * bit or the O bit is set. If neither bit is set, the Residual Count
+     * field MUST be ignored on reception and SHOULD be set to 0 when
+     * sending. Targets may set the residual count, and initiators may use
+     * it when the response code is Command Completed at Target (even if the
+     * status returned is not GOOD). If the O bit is set, the Residual
+     * Count indicates the number of bytes that were not transferred because
+     * the initiator's Expected Data Transfer Length was not sufficient. If
+     * the U bit is set, the Residual Count indicates the number of bytes
+     * that were not transferred out of the number of bytes expected to be
+     * transferred.
+     */
+    uint32_t res_cnt;
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
+
+    /// Optional data segment, command data.
+    iscsi_ds_cmd_data ds_cmd_data;
+
+    /// Optional data digest.
+    iscsi_data_digest data_digest;
 } iscsi_scsi_response_packet;
 
-#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_ABORT_TASK         0x01 // ABORT TASK - aborts the task identified by the Referenced Task Tag field
-#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_ABORT_TASK_SET     0x02 // ABORT TASK SET - aborts all tasks issued via this session on the LU
-#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_CLEAR_ACA          0x03 // CLEAR ACA - clears the Auto Contingent Allegiance condition
-#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_CLEAR_TASK_SET     0x04 // CLEAR TASK SET - aborts all tasks in the appropriate task set
-                                                              // as defined by the TST field in the Control mode page
-                                                              // (see SPC3)
-#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_LOGICAL_UNIT_RESET 0x05 // LOGICAL UNIT RESET
-#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_TARGET_WARM_RESET  0x06 // TARGET WARM RESET
-#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_TARGET_COLD_RESET  0x07 // TARGET COLD RESET
-#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_TASK_REASSIGN      0x08 // TASK REASSIGN - reassigns connection allegiance for the task
-                                                              // identified by the Initiator Task Tag field to this connection,
-                                                              // thus resuming the iSCSI exchanges for the task
 
+/// Task management request function: ABORT TASK: aborts the task identified by the Referenced Task Tag field.
+#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_ABORT_TASK         0x01
+
+/// Task management request function: ABORT TASK SET: aborts all tasks issued via this session on the LU.
+#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_ABORT_TASK_SET     0x02
+
+/// Task management request function: CLEAR ACA - clears the Auto Contingent Allegiance condition.
+#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_CLEAR_ACA          0x03
+
+/// Task management request function: CLEAR TASK SET - aborts all tasks in the appropriate task set as defined by the TST field in the Control mode page (see SPC3).
+#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_CLEAR_TASK_SET     0x04
+
+/// Task management request function: LOGICAL UNIT RESET.
+#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_LOGICAL_UNIT_RESET 0x05
+
+/// Task management request function: TARGET WARM RESET.
+#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_TARGET_WARM_RESET  0x06
+
+/// Task management request function: TARGET COLD RESET.
+#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_TARGET_COLD_RESET  0x07
+
+/// Task management request function: TASK REASSIGN - reassigns connection allegiance for the task identified by the Initiator Task Tag field to this connection, thus resuming the iSCSI exchanges for the task.
+#define ISCSI_TASK_MGMT_FUNC_REQ_FUNC_TASK_REASSIGN      0x08
+
+
+/**
+ * @brief iSCSI Task Management Function Request packet data.
+ *
+ * This structure is used to explicity control the execution of one
+ * or more tasks (iSCSI and SCSI).
+ */
 typedef struct __attribute__((packed)) iscsi_task_mgmt_func_req_packet {
-    uint8_t opcode; // Always 0x02 according to specification (see above)
-    uint8_t func; // Function.
-                  // The task management functions provide an initiator with a way to
-                  // explicitly control the execution of one or more tasks (SCSI and iSCSI
-                  // tasks). The task management function codes are listed below. For a
-                  // more detailed description of SCSI task management, see SAM2.
-    uint16_t reserved; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength (MUST be 0 for this PDU)
-    uint8_t ds_len[3]; // DataSegmentLength (MUST be 0 for this PDU)
-    uint64_t lun; // Logical Unit Number (LUN) or Reserved
-                  // This field is required for functions that address a specific LU
-                  // (ABORT TASK, CLEAR TASK SET, ABORT TASK SET, CLEAR ACA, LOGICAL UNIT
-                  // RESET) and is reserved in all others
-    uint32_t init_task_tag; // Initiator task tag
-                            // This is the Initiator Task Tag of the task to be aborted for the
-                            // ABORT TASK function or reassigned for the TASK REASSIGN function.
-                            // For all the other functions, this field MUST be set to the reserved
-                            // value 0xFFFFFFFF
-    uint32_t ref_task_tag; // Referenced task tag or 0xFFFFFFFF
-    uint32_t cmd_sn; // CmdSN
-    uint32_t exp_stat_sn; // ExpStatSN
-    uint32_t ref_cmd_sn; // RefCmdSN or Reserved
-                         // If an ABORT TASK is issued for a task created by an immediate
-                         // command, then the RefCmdSN MUST be that of the task management
-                         // request itself (i.e., the CmdSN and RefCmdSN are equal).
-                         // For an ABORT TASK of a task created by a non-immediate command, the
-                         // RefCmdSN MUST be set to the CmdSN of the task identified by the
-                         // Referenced Task Tag field. Targets must use this field when the task
-                         // identified by the Referenced Task Tag field is not with the target.
-                         // Otherwise, this field is reserved
-    uint32_t exp_data_sn; // ExpDataSN or Reserved
-                          // For recovery purposes, the iSCSI target and initiator maintain a data
-                          // acknowledgment reference number - the first input DataSN number
-                          // unacknowledged by the initiator. When issuing a new command, this
-                          // number is set to 0. If the function is TASK REASSIGN, which
-                          // establishes a new connection allegiance for a previously issued read
-                          // or bidirectional command, the ExpDataSN will contain an updated data
-                          // acknowledgment reference number or the value 0; the latter indicates
-                          // that the data acknowledgment reference number is unchanged. The
-                          // initiator MUST discard any data PDUs from the previous execution that
-                          // it did not acknowledge, and the target MUST transmit all Data-In PDUs
-                          // (if any) starting with the data acknowledgment reference number. The
-                          // number of retransmitted PDUs may or may not be the same as the
-                          // original transmission, depending on if there was a change in
-                          // MaxRecvDataSegmentLength in the reassignment. The target MAY also
-                          // send no more Data-In PDUs if all data has been acknowledged.
-                          // The value of ExpDataSN MUST be 0 or higher than the DataSN of the
-                          // last acknowledged Data-In PDU, but not larger than DataSN + 1 of the
-                          // last Data-IN PDU sent by the target. Any other value MUST be ignored
-                          // by the target.
-                          // For other functions, this field is reserved
-    uint64_t reserved2; // Reserved for future usage
-    struct iscsi_header_digest hdr_digest; // Optional header digest
+    /// Always 2 according to iSCSI specification.
+    uint8_t opcode;
+
+    /**
+     * @brief Function.
+     *
+     * The task management functions provide an initiator with a way to
+     * explicitly control the execution of one or more tasks (SCSI and iSCSI
+     * tasks). The task management function codes are listed below. For a
+     * more detailed description of SCSI task management, see SAM2.
+     */
+    int8_t func;
+
+    /// Reserved fot future usage, always MUST be 0.
+    uint16_t reserved;
+
+    /// TotalAHSLength (MUST be 0 for this PDU).
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength (MUST be 0 for this PDU).
+    uint8_t ds_len[3];
+
+    /**
+     * @brief Logical Unit Number (LUN) or Reserved.
+     *
+     * This field is required for functions that address a specific LU
+     * (ABORT TASK, CLEAR TASK SET, ABORT TASK SET, CLEAR ACA, LOGICAL UNIT
+     * RESET) and is reserved in all others
+     */
+    uint64_t lun;
+
+    /**
+     * @brief Initiator Task Tag (ITT).
+     *
+     * This is the Initiator Task Tag of the task to be aborted for the
+     * ABORT TASK function or reassigned for the TASK REASSIGN function.
+     * For all the other functions, this field MUST be set to the reserved
+     * value 0xFFFFFFFF.
+     */
+    uint32_t init_task_tag;
+
+    /// Referenced task tag or 0xFFFFFFFF.
+    uint32_t ref_task_tag;
+
+    /// CmdSN.
+    uint32_t cmd_sn;
+
+    /// ExpStatSN
+    uint32_t exp_stat_sn;
+
+    /**
+     * @brief RefCmdSN or Reserved.
+     *
+     * If an ABORT TASK is issued for a task created by an immediate
+     * command, then the RefCmdSN MUST be that of the task management
+     * request itself (i.e., the CmdSN and RefCmdSN are equal).\n
+     * For an ABORT TASK of a task created by a non-immediate command, the
+     * RefCmdSN MUST be set to the CmdSN of the task identified by the
+     * Referenced Task Tag field. Targets must use this field when the task
+     * identified by the Referenced Task Tag field is not with the target.
+     * Otherwise, this field is reserved.
+     */
+    uint32_t ref_cmd_sn;
+
+    /**
+     * @brief ExpDataSN or Reserved.
+     *
+     * For recovery purposes, the iSCSI target and initiator maintain a data
+     * acknowledgment reference number - the first input DataSN number
+     * unacknowledged by the initiator. When issuing a new command, this
+     * number is set to 0. If the function is TASK REASSIGN, which
+     * establishes a new connection allegiance for a previously issued read
+     * or bidirectional command, the ExpDataSN will contain an updated data
+     * acknowledgment reference number or the value 0; the latter indicates
+     * that the data acknowledgment reference number is unchanged. The
+     * initiator MUST discard any data PDUs from the previous execution that
+     * it did not acknowledge, and the target MUST transmit all Data-In PDUs
+     * (if any) starting with the data acknowledgment reference number. The
+     * number of retransmitted PDUs may or may not be the same as the
+     * original transmission, depending on if there was a change in
+     * MaxRecvDataSegmentLength in the reassignment. The target MAY also
+     * send no more Data-In PDUs if all data has been acknowledged.
+     * The value of ExpDataSN MUST be 0 or higher than the DataSN of the
+     * last acknowledged Data-In PDU, but not larger than DataSN + 1 of the
+     * last Data-IN PDU sent by the target. Any other value MUST be ignored
+     * by the target.
+     * For other functions, this field is reserved
+     */
+    uint32_t exp_data_sn;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint64_t reserved2;
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
 } iscsi_task_mgmt_func_req_packet;
 
-#define ISCSI_TASK_MGMT_FUNC_RESPONSE_FUNC_COMPLETE               0x00 // Function complete
-#define ISCSI_TASK_MGMT_FUNC_RESPONSE_TASK_NO_EXIST               0x01 // Task does not exist
-#define ISCSI_TASK_MGMT_FUNC_RESPONSE_LUN_NO_EXIST                0x02 // LUN does not exist
-#define ISCSI_TASK_MGMT_FUNC_RESPONSE_TASK_ALLEGIANT              0x03 // Task still allegiant
-#define ISCSI_TASK_MGMT_FUNC_RESPONSE_TASK_UNSUPPORTED_ALLEGIANCE 0x04 // Task allegiance reassignment not supported
-#define ISCSI_TASK_MGMT_FUNC_RESPONSE_TASK_UNSUPPORTED_MGMT       0x05 // Task management function not supported
-#define ISCSI_TASK_MGMT_FUNC_RESPONSE_FUNC_AUTH_FAILED            0x06 // Function authorization failed
-#define ISCSI_TASK_MGMT_FUNC_RESPONSE_FUNC_REJECTED               0xFF // Function rejected
-
-/* For the functions ABORT TASK, ABORT TASK SET, CLEAR ACA, CLEAR TASK
-   SET, LOGICAL UNIT RESET, TARGET COLD RESET, TARGET WARM RESET, and
-   TASK REASSIGN, the target performs the requested task management
-   function and sends a task management response back to the initiator.
-   For TASK REASSIGN, the new connection allegiance MUST ONLY become
-   effective at the target after the target issues the task management
-   response.
-*/
+
+/// Task management function response: Function complete.
+#define ISCSI_TASK_MGMT_FUNC_RESPONSE_FUNC_COMPLETE               0x00
+
+/// Task management function response: Task does not exist.
+#define ISCSI_TASK_MGMT_FUNC_RESPONSE_TASK_NO_EXIST               0x01
+
+/// Task management function response: LUN does not exist.
+#define ISCSI_TASK_MGMT_FUNC_RESPONSE_LUN_NO_EXIST                0x02
+
+/// Task management function response: Task still allegiant.
+#define ISCSI_TASK_MGMT_FUNC_RESPONSE_TASK_ALLEGIANT              0x03
+
+/// Task management function response: Task allegiance reassignment not supported.
+#define ISCSI_TASK_MGMT_FUNC_RESPONSE_TASK_UNSUPPORTED_ALLEGIANCE 0x04
+
+/// Task management function response: Task management function not supported.
+#define ISCSI_TASK_MGMT_FUNC_RESPONSE_TASK_UNSUPPORTED_MGMT       0x05
+
+/// Task management function response: Function authorization failed.
+#define ISCSI_TASK_MGMT_FUNC_RESPONSE_FUNC_AUTH_FAILED            0x06
+
+/// Task management function response: Function rejected.
+#define ISCSI_TASK_MGMT_FUNC_RESPONSE_FUNC_REJECTED               0xFF
+
+
+/**
+ * @brief iSCSI Task Management Function Response packet data.
+ *
+ * For the functions ABORT TASK, ABORT TASK SET, CLEAR ACA, CLEAR TASK
+ * SET, LOGICAL UNIT RESET, TARGET COLD RESET, TARGET WARM RESET, and
+ * TASK REASSIGN, the target performs the requested task management
+ * function and sends a task management response back to the initiator.
+ * For TASK REASSIGN, the new connection allegiance MUST ONLY become
+ * effective at the target after the target issues the task management
+ * response.
+ */
 typedef struct __attribute__((packed)) iscsi_task_mgmt_func_response_packet {
-    uint8_t opcode; // Always 0x22 according to specification (see above)
-    uint8_t flags; // Reserved for future usage
-    uint8_t response; // Function response (see above)
-                      // For the TARGET COLD RESET and TARGET WARM RESET functions, the target
-                      // cancels all pending operations across all LUs known to the issuing
-                      // initiator. For the TARGET COLD RESET function, the target MUST then
-                      // close all of its TCP connections to all initiators (terminates all
-                      // sessions).
-                      // The mapping of the response code into a SCSI service response code
-                      // value, if needed, is outside the scope of this document. However, in
-                      // symbolic terms, Response values 0 and 1 map to the SCSI service
-                      // response of FUNCTION COMPLETE. Response value 2 maps to the SCSI
-                      // service response of INCORRECT LOGICAL UNIT NUMBER. All other
-                      // Response values map to the SCSI service response of FUNCTION
-                      // REJECTED. If a Task Management Function Response PDU does not arrive
-                      // before the session is terminated, the SCSI service response is
-                      // SERVICE DELIVERY OR TARGET FAILURE.
-                      // The response to ABORT TASK SET and CLEAR TASK SET MUST only be issued
-                      // by the target after all of the commands affected have been received
-                      // by the target, the corresponding task management functions have been
-                      // executed by the SCSI target, and the delivery of all responses
-                      // delivered until the task management function completion has been
-                      // confirmed (acknowledged through the ExpStatSN) by the initiator on
-                      // all connections of this session.
-                      // For the ABORT TASK function,
-                      // a) if the Referenced Task Tag identifies a valid task leading to a
-                      //    successful termination, then targets must return the "Function
-                      //    complete" response.
-                      // b) if the Referenced Task Tag does not identify an existing task
-                      //    but the CmdSN indicated by the RefCmdSN field in the Task
-                      //    Management Function Request is within the valid CmdSN window
-                      //    and less than the CmdSN of the Task Management Function Request
-                      //    itself, then targets must consider the CmdSN as received and
-                      //    return the "Function complete" response.
-                      // c) if the Referenced Task Tag does not identify an existing task
-                      //    and the CmdSN indicated by the RefCmdSN field in the Task
-                      //    Management Function Request is outside the valid CmdSN window,
-                      //    then targets must return the "Task does not exist" response
-    uint8_t reserved; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength (MUST be 0 for this PDU)
-    uint8_t ds_len[3]; // DataSegmentLength (MUST be 0 for this PDU)
-    uint64_t reserved2; // Reserved for future usage
-    uint32_t init_task_tag; // Initiator task tag
-    uint32_t reserved3; // Reserved for future usage
-    uint32_t stat_sn; // StatSN
-    uint32_t exp_cmd_sn; // ExpCmdSN
-    uint32_t max_cmd_sn; // MaxCmdSN
-    uint32_t reserved4; // Reserved for future usage
-    uint64_t reserved5; // Reserved for future usage
-    struct iscsi_header_digest hdr_digest; // Optional header digest
+    /// Always 0x22 according to specification.
+    uint8_t opcode;
+
+    /// Reserved for future usage (must be always 0x80 for now).
+    int8_t flags;
+
+    /**
+     * @brief Function response.
+     *
+     * For the TARGET COLD RESET and TARGET WARM RESET functions, the target
+     * cancels all pending operations across all LUs known to the issuing
+     * initiator. For the TARGET COLD RESET function, the target MUST then
+     * close all of its TCP connections to all initiators (terminates all
+     * sessions).\n
+     * The mapping of the response code into a SCSI service response code
+     * value, if needed, is outside the scope of this document. However, in
+     * symbolic terms, Response values 0 and 1 map to the SCSI service
+     * response of FUNCTION COMPLETE. Response value 2 maps to the SCSI
+     * service response of INCORRECT LOGICAL UNIT NUMBER. All other
+     * Response values map to the SCSI service response of FUNCTION
+     * REJECTED. If a Task Management Function Response PDU does not arrive
+     * before the session is terminated, the SCSI service response is
+     * SERVICE DELIVERY OR TARGET FAILURE.\n
+     * The response to ABORT TASK SET and CLEAR TASK SET MUST only be issued
+     * by the target after all of the commands affected have been received
+     * by the target, the corresponding task management functions have been
+     * executed by the SCSI target, and the delivery of all responses
+     * delivered until the task management function completion has been
+     * confirmed (acknowledged through the ExpStatSN) by the initiator on
+     * all connections of this session.\n
+     * For the ABORT TASK function,\n
+     * -# if the Referenced Task Tag identifies a valid task leading to a
+     *    successful termination, then targets must return the "Function
+     *    complete" response.
+     * -# if the Referenced Task Tag does not identify an existing task
+     *    but the CmdSN indicated by the RefCmdSN field in the Task
+     *    Management Function Request is within the valid CmdSN window
+     *    and less than the CmdSN of the Task Management Function Request
+     *    itself, then targets must consider the CmdSN as received and
+     *    return the "Function complete" response.
+     * -# if the Referenced Task Tag does not identify an existing task
+     *    and the CmdSN indicated by the RefCmdSN field in the Task
+     *    Management Function Request is outside the valid CmdSN window,
+     *    then targets must return the "Task does not exist" response
+     */
+    uint8_t response;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint8_t reserved;
+
+    /// TotalAHSLength (MUST be 0 for this PDU).
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength (MUST be 0 for this PDU).
+    uint8_t ds_len[3];
+
+    /// Reserved for future usage, always MUST be 0.
+    uint64_t reserved2;
+
+    /// Initiator Task Tag (ITT).
+    uint32_t init_task_tag;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved3;
+
+    /// StatSN.
+    uint32_t stat_sn;
+
+    /// ExpCmdSN.
+    uint32_t exp_cmd_sn;
+
+    /// MaxCmdSN.
+    uint32_t max_cmd_sn;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved4;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint64_t reserved5;
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
 } iscsi_task_mgmt_func_response_packet;
 
-#define ISCSI_SCSI_DATA_OUT_DATA_IN_FLAGS_IMMEDIATE   (1 << 7) // Immediately process transfer
+/// SCSI data out / in flags: Immediately process transfer.
+#define ISCSI_SCSI_DATA_OUT_DATA_IN_FLAGS_IMMEDIATE (1 << 7)
 
+/**
+ * @brief iSCSI SCSI Data Out request packet data.
+ *
+ * THis structure is used by iSCSI for SCSI data output
+ * requests, i.e. write operations.
+ */
 typedef struct __attribute__((packed)) iscsi_scsi_data_out_req_packet {
-    uint8_t opcode; // Always 0x02 according to specification (see above)
-    int8_t flags; // Flags (see above)
-    uint16_t reserved; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength (MUST be 0 for this PDU)
-    uint8_t ds_len[3]; // DataSegmentLength (MUST be 0 for this PDU)
-    uint64_t lun; // Logical Unit Number (LUN) or Reserved
-    uint32_t init_task_tag; // Initiator task tag
-    uint32_t target_xfer_tag; // Target transfer tag or 0xFFFFFFFF
-    uint32_t reserved2; // Reserved for future usage
-    uint32_t exp_stat_sn; // ExpStatSN
-    uint32_t reserved3; // Reserved for future usage
-    uint32_t data_sn; // DataSN
-    uint32_t buf_offset; // Buffer offset
-    uint32_t reserved4; // Reserved for future usage
-    struct iscsi_header_digest hdr_digest; // Optional header digest
-    struct iscsi_data_digest data_digest; // Optional data digest
+    /// Always 2 according to iSCSI specification.
+    uint8_t opcode;
+
+    /// Flags.
+    int8_t flags;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint16_t reserved;
+
+    /// TotalAHSLength.
+    uint8_t total_ahs_len;
+
+    /**
+     * @brief DataSegmentLength.
+     *
+     * This is the data payload length of a SCSI Data-In or SCSI Data-Out
+     * PDU. The sending of 0-length data segments should be avoided, but
+     * initiators and targets MUST be able to properly receive 0-length data
+     * segments.\n
+     * The data segments of Data-In and Data-Out PDUs SHOULD be filled to
+     * the integer number of 4-byte words (real payload), unless the F bit
+     * is set to 1.
+     */
+    uint8_t ds_len[3];
+
+    /**
+     * @brief Logical Unit Number (LUN) or Reserved.
+     *
+     * If the Target Transfer Tag is provided, then the LUN field MUST hold a
+     * valid value and be consistent with whatever was specified with the command;
+     * otherwise, the LUN field is reserved.
+     */
+    uint64_t lun;
+
+    /// Initiator Task Tag (ITT).
+    uint32_t init_task_tag;
+
+    /**
+     * @brief Target Transfer Tag or 0xFFFFFFFF.
+     *
+     * On outgoing data, the Target Transfer Tag is provided to the target
+     * if the transfer is honoring an R2T. In this case, the Target
+     * Transfer Tag field is a replica of the Target Transfer Tag provided
+     * with the R2T.\n
+     * The Target Transfer Tag values are not specified by this protocol,
+     * except that the value 0xFFFFFFFF is reserved and means that the
+     * Target Transfer Tag is not supplied.
+     */
+    uint32_t target_xfer_tag;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved2;
+
+    /// ExpStatSN.
+    uint32_t exp_stat_sn;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved3;
+
+    /**
+     * @brief DataSN.
+     *
+     * For output (write) data PDUs, the DataSN is the Data-Out PDU number
+     * within the current output sequence. Either the current output
+     * sequence is identified by the Initiator Task Tag (for unsolicited
+     * data) or it is a data sequence generated for one R2T (for data
+     * solicited through R2T).
+     */
+    uint32_t data_sn;
+
+    /**
+     * @brief Buffer Offset.
+     *
+     * The Buffer Offset field contains the offset of this PDU payload data
+     * within the complete data transfer. The sum of the buffer offset and
+     * length should not exceed the expected transfer length for the
+     * command.\n
+     * The order of data PDUs within a sequence is determined by
+     * DataPDUInOrder. When set to Yes, it means that PDUs have to be in
+     * increasing buffer offset order and overlays are forbidden.\n
+     * The ordering between sequences is determined by DataSequenceInOrder.
+     * When set to Yes, it means that sequences have to be in increasing
+     * buffer offset order and overlays are forbidden.
+     */
+    uint32_t buf_offset;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved4;
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
+
+    /// Data segment.
+    iscsi_ds_cmd_data ds_cmd_data;
+
+    /// Optional data digest.
+    iscsi_data_digest data_digest;
 } iscsi_scsi_data_out_req_packet;
 
-#define ISCSI_SCSI_DATA_IN_RESPONSE_FLAGS_STATUS        (1 << 0) // (S) set to indicate that the Command Status field
-                                                                 // contains status. If this bit is set to 1, the
-                                                                 // F bit MUST also be set to 1
-
-#define ISCSI_SCSI_DATA_IN_RESPONSE_FLAGS_RES_UNDERFLOW (1 << 1) // (U) set for Residual Underflow. In this case, the Residual
-                                                                 // Count indicates the number of bytes that were not
-                                                                 // transferred out of the number of bytes that were expected
-                                                                 // to be transferred. For a bidirectional operation, the
-                                                                 // Residual Count contains the residual for the write
-                                                                 // operation.
-
-#define ISCSI_SCSI_DATA_IN_RESPONSE_FLAGS_RES_OVERFLOW  (1 << 2) // (O) set for Residual Overflow. In this case, the Residual
-                                                                 // Count indicates the number of bytes that were not
-                                                                 // transferred because the initiator's Expected Data
-                                                                 // Transfer Length was not sufficient. For a bidirectional
-                                                                 // operation, the Residual Count contains the residual for
-                                                                 // the write operation.
-
-#define ISCSI_SCSI_DATA_IN_RESPONSE_FLAGS_ACK           (1 << 6) // (A) for sessions with ErrorRecoveryLevel=1 or higher, the target sets
-                                                                 // this bit to 1 to indicate that it requests a positive acknowledgment
-                                                                 // from the initiator for the data received. The target should use the
-                                                                 // A bit moderately; it MAY only set the A bit to 1 once every
-                                                                 // MaxBurstLength bytes, or on the last Data-In PDU that concludes the
-                                                                 // entire requested read data transfer for the task from the target's
-                                                                 // perspective, and it MUST NOT do so more frequently. The target MUST
-                                                                 // NOT set to 1 the A bit for sessions with ErrorRecoveryLevel=0. The
-                                                                 // initiator MUST ignore the A bit set to 1 for sessions with
-                                                                 // ErrorRecoveryLevel=0.
-                                                                 // On receiving a Data-In PDU with the A bit set to 1 on a session with
-                                                                 // ErrorRecoveryLevel greater than 0, if there are no holes in the read
-                                                                 // data until that Data-In PDU, the initiator MUST issue a SNACK of type
-                                                                 // DataACK, except when it is able to acknowledge the status for the
-                                                                 // task immediately via the ExpStatSN on other outbound PDUs if the
-                                                                 // status for the task is also received. In the latter case
-                                                                 // (acknowledgment through the ExpStatSN), sending a SNACK of type
-                                                                 // DataACK in response to the A bit is OPTIONAL, but if it is done, it
-                                                                 // must not be sent after the status acknowledgment through the
-                                                                 // ExpStatSN. If the initiator has detected holes in the read data
-                                                                 // prior to that Data-In PDU, it MUST postpone issuing the SNACK of type
-                                                                 // DataACK until the holes are filled. An initiator also MUST NOT
-                                                                 // acknowledge the status for the task before those holes are filled. A
-                                                                 // status acknowledgment for a task that generated the Data-In PDUs is
-                                                                 // considered by the target as an implicit acknowledgment of the Data-In
-                                                                 // PDUs if such an acknowledgment was requested by the target
-
-#define ISCSI_SCSI_DATA_IN_RESPONSE_FLAGS_FINAL         (1 << 7) // (F) for outgoing data, this bit is 1 for the last PDU of unsolicited
-                                                                 // data or the last PDU of a sequence that answers an R2T.
-                                                                 // For incoming data, this bit is 1 for the last input (read) data PDU
-                                                                 // of a sequence. Input can be split into several sequences, each
-                                                                 // having its own F bit. Splitting the data stream into sequences does
-                                                                 // not affect DataSN counting on Data-In PDUs. It MAY be used as a
-                                                                 // "change direction" indication for bidirectional operations that need
-                                                                 // such a change.
-                                                                 // DataSegmentLength MUST NOT exceed MaxRecvDataSegmentLength for the
-                                                                 // direction it is sent, and the total of all the DataSegmentLength of
-                                                                 // all PDUs in a sequence MUST NOT exceed MaxBurstLength (or
-                                                                 // FirstBurstLength for unsolicited data). However, the number of
-                                                                 // individual PDUs in a sequence (or in total) may be higher than the
-                                                                 // ratio of MaxBurstLength (or FirstBurstLength) to
-                                                                 // MaxRecvDataSegmentLength (as PDUs may be limited in length by the
-                                                                 // capabilities of the sender). Using a DataSegmentLength of 0 may
-                                                                 // increase beyond what is reasonable for the number of PDUs and should
-                                                                 // therefore be avoided.
-                                                                 // For bidirectional operations, the F bit is 1 for both the end of the
-                                                                 // input sequences and the end of the output sequences
+/**
+ * @brief SCSI Data In reponse flags: Status.
+ *
+ * (S) set to indicate that the Command Status field
+ * contains status. If this bit is set to 1, the
+ * F bit MUST also be set to 1.
+ */
+#define ISCSI_SCSI_DATA_IN_RESPONSE_FLAGS_STATUS        (1 << 0)
+
+/**
+ * @brief SCSI Data In reponse flags: Residual Underflow.
+ *
+ * (U) set for Residual Underflow. In this case, the Residual
+ * Count indicates the number of bytes that were not
+ * transferred out of the number of bytes that were expected
+ * to be transferred. For a bidirectional operation, the
+ * Residual Count contains the residual for the write
+ * operation.
+ */
+#define ISCSI_SCSI_DATA_IN_RESPONSE_FLAGS_RES_UNDERFLOW (1 << 1)
 
+/**
+ * @brief SCSI Data In reponse flags: Residual Overflow.
+ *
+ * (O) set for Residual Overflow. In this case, the Residual
+ * Count indicates the number of bytes that were not
+ * transferred because the initiator's Expected Data
+ * Transfer Length was not sufficient. For a bidirectional
+ * operation, the Residual Count contains the residual for
+ * the write operation.
+ */
+#define ISCSI_SCSI_DATA_IN_RESPONSE_FLAGS_RES_OVERFLOW  (1 << 2)
+
+/**
+ * @brief SCSI Data In reponse flags: ACK.
+ *
+ * (A) for sessions with ErrorRecoveryLevel=1 or higher, the target sets
+ * this bit to 1 to indicate that it requests a positive acknowledgment
+ * from the initiator for the data received. The target should use the
+ * A bit moderately; it MAY only set the A bit to 1 once every
+ * MaxBurstLength bytes, or on the last Data-In PDU that concludes the
+ * entire requested read data transfer for the task from the target's
+ * perspective, and it MUST NOT do so more frequently. The target MUST
+ * NOT set to 1 the A bit for sessions with ErrorRecoveryLevel=0. The
+ * initiator MUST ignore the A bit set to 1 for sessions with
+ * ErrorRecoveryLevel=0.\n
+ * On receiving a Data-In PDU with the A bit set to 1 on a session with
+ * ErrorRecoveryLevel greater than 0, if there are no holes in the read
+ * data until that Data-In PDU, the initiator MUST issue a SNACK of type
+ * DataACK, except when it is able to acknowledge the status for the
+ * task immediately via the ExpStatSN on other outbound PDUs if the
+ * status for the task is also received. In the latter case
+ * (acknowledgment through the ExpStatSN), sending a SNACK of type
+ * DataACK in response to the A bit is OPTIONAL, but if it is done, it
+ * must not be sent after the status acknowledgment through the
+ * ExpStatSN. If the initiator has detected holes in the read data
+ * prior to that Data-In PDU, it MUST postpone issuing the SNACK of type
+ * DataACK until the holes are filled. An initiator also MUST NOT
+ * acknowledge the status for the task before those holes are filled. A
+ * status acknowledgment for a task that generated the Data-In PDUs is
+ * considered by the target as an implicit acknowledgment of the Data-In
+ * PDUs if such an acknowledgment was requested by the target.
+ */
+#define ISCSI_SCSI_DATA_IN_RESPONSE_FLAGS_ACK           (1 << 6)
+
+/**
+ * @brief SCSI Data In reponse flags: Final.
+ *
+ * (F) for outgoing data, this bit is 1 for the last PDU of unsolicited
+ * data or the last PDU of a sequence that answers an R2T.
+ * For incoming data, this bit is 1 for the last input (read) data PDU
+ * of a sequence. Input can be split into several sequences, each
+ * having its own F bit. Splitting the data stream into sequences does
+ * not affect DataSN counting on Data-In PDUs. It MAY be used as a
+ * "change direction" indication for bidirectional operations that need
+ * such a change.\n
+ * DataSegmentLength MUST NOT exceed MaxRecvDataSegmentLength for the
+ * direction it is sent, and the total of all the DataSegmentLength of
+ * all PDUs in a sequence MUST NOT exceed MaxBurstLength (or
+ * FirstBurstLength for unsolicited data). However, the number of
+ * individual PDUs in a sequence (or in total) may be higher than the
+ * ratio of MaxBurstLength (or FirstBurstLength) to
+ * MaxRecvDataSegmentLength (as PDUs may be limited in length by the
+ * capabilities of the sender). Using a DataSegmentLength of 0 may
+ * increase beyond what is reasonable for the number of PDUs and should
+ * therefore be avoided.\n
+ * For bidirectional operations, the F bit is 1 for both the end of the
+ * input sequences and the end of the output sequences
+ */
+#define ISCSI_SCSI_DATA_IN_RESPONSE_FLAGS_FINAL         (1 << 7)
+
+/**
+ * @brief iSCSI SCSI Data In response packet data.
+ *
+ * THis structure is used by iSCSI for SCSI data input
+ * responses, i.e. read operations.
+ */
 typedef struct __attribute__((packed)) iscsi_scsi_data_in_response_packet {
-    uint8_t opcode; // Always 0x25 according to specification (see above)
-    int8_t flags; // Incoming data flags (see above)
-                  // The fields StatSN, Status, and Residual Count only have meaningful
-                  // content if the S bit is set to 1
-    uint8_t reserved; // Rserved for future usage
-    uint8_t status; // Status or Reserved
-                    // Status can accompany the last Data-In PDU if the command did not end
-                    // with an exception (i.e., the status is "good status" - GOOD,
-                    // CONDITION MET, or INTERMEDIATE-CONDITION MET). The presence of
-                    // status (and of a residual count) is signaled via the S flag bit.
-                    // Although targets MAY choose to send even non-exception status in
-                    // separate responses, initiators MUST support non-exception status in
-                    // Data-In PDUs
-    uint8_t total_ahs_len; // TotalAHSLength
-    uint8_t ds_len[3]; // DataSegmentLength
-                       // This is the data payload length of a SCSI Data-In or SCSI Data-Out
-                       // PDU. The sending of 0-length data segments should be avoided, but
-                       // initiators and targets MUST be able to properly receive 0-length data
-                       // segments.
-                       // The data segments of Data-In and Data-Out PDUs SHOULD be filled to
-                       // the integer number of 4-byte words (real payload), unless the F bit
-                       // is set to 1
-    uint64_t lun; // Logical Unit Number (LUN) or Reserved
-                  // If the Target Transfer Tag isprovided, then the LUN field MUST hold a
-                  // valid value and be consistent with whatever was specified with the command;
-                  // otherwise, the LUN field is reserved
-    uint32_t init_task_tag; // Initiator task tag
-    uint32_t target_xfer_tag; // On outgoing data, the Target Transfer Tag is provided to the target
-                              // if the transfer is honoring an R2T. In this case, the Target
-                              // Transfer Tag field is a replica of the Target Transfer Tag provided
-                              // with the R2T.
-                              // On incoming data, the Target Transfer Tag and LUN MUST be provided by
-                              // the target if the A bit is set to 1; otherwise, they are reserved.
-                              // The Target Transfer Tag and LUN are copied by the initiator into the
-                              // SNACK of type DataACK that it issues as a result of receiving a SCSI
-                              // Data-In PDU with the A bit set to 1.
-                              // The Target Transfer Tag values are not specified by this protocol,
-                              // except that the value 0xFFFFFFFF is reserved and means that the
-                              // Target Transfer Tag is not supplied
-    uint32_t stat_sn; // StatSN
-    uint32_t exp_cmd_sn; // ExpCmdSN
-    uint32_t max_cmd_sn; // MaxCmdSN
-    uint32_t data_sn; // DataSN
-                      // For input (read) or bidirectional Data-In PDUs, the DataSN is the
-                      // input PDU number within the data transfer for the command identified
-                      // by the Initiator Task Tag.
-                      // R2T and Data-In PDUs, in the context of bidirectional commands, share
-                      // the numbering sequence.
-                      // For output (write) data PDUs, the DataSN is the Data-Out PDU number
-                      // within the current output sequence. Either the current output
-                      // sequence is identified by the Initiator Task Tag (for unsolicited
-                      // data) or it is a data sequence generated for one R2T (for data
-                      // solicited through R2T)
-    uint32_t buf_offset; // Buffer Offset
-                         // The Buffer Offset field contains the offset of this PDU payload data
-                         // within the complete data transfer. The sum of the buffer offset and
-                         // length should not exceed the expected transfer length for the
-                         // command.
-                         // The order of data PDUs within a sequence is determined by
-                         // DataPDUInOrder. When set to Yes, it means that PDUs have to be in
-                         // increasing buffer offset order and overlays are forbidden.
-                         // The ordering between sequences is determined by DataSequenceInOrder.
-                         // When set to Yes, it means that sequences have to be in increasing
-                         // buffer offset order and overlays are forbidden
-    uint32_t res_cnt; // Residual Count or Reserved
-    struct iscsi_header_digest hdr_digest; // Optional header digest
-    struct iscsi_ds_cmd_data ds_cmd_data; // Data segment
-    struct iscsi_data_digest data_digest; // Optional data digest
+    /// Always 0x25 according to iSCSI specification.
+    uint8_t opcode;
+
+    /// Incoming data flags. The fields StatSN, Status, and Residual Count only have meaningful content if the S bit is set to 1.
+    int8_t flags;
+
+    /// Rserved for future usage, always MUST be 0.
+    uint8_t reserved;
+
+    /**
+     * @brief Status or Reserved.
+     *
+     * Status can accompany the last Data-In PDU if the command did not end
+     * with an exception (i.e., the status is "good status" - GOOD,
+     * CONDITION MET, or INTERMEDIATE-CONDITION MET). The presence of
+     * status (and of a residual count) is signaled via the S flag bit.
+     * Although targets MAY choose to send even non-exception status in
+     * separate responses, initiators MUST support non-exception status in
+     * Data-In PDUs.
+     */
+    uint8_t status;
+
+    /// TotalAHSLength.
+    uint8_t total_ahs_len;
+
+    /**
+     * @brief DataSegmentLength.
+     *
+     * This is the data payload length of a SCSI Data-In or SCSI Data-Out
+     * PDU. The sending of 0-length data segments should be avoided, but
+     * initiators and targets MUST be able to properly receive 0-length data
+     * segments.\n
+     * The data segments of Data-In and Data-Out PDUs SHOULD be filled to
+     * the integer number of 4-byte words (real payload), unless the F bit
+     * is set to 1.
+     */
+    uint8_t ds_len[3];
+
+    /**
+     * @brief Logical Unit Number (LUN) or Reserved.
+     *
+     * If the Target Transfer Tag is provided, then the LUN field MUST hold a
+     * valid value and be consistent with whatever was specified with the command;
+     * otherwise, the LUN field is reserved.
+     */
+    uint64_t lun;
+
+    /// Initiator Task Tag (ITT).
+    uint32_t init_task_tag;
+
+    /**
+     * @brief Target Transfer Tag or 0xFFFFFFFF.
+     *
+     * On incoming data, the Target Transfer Tag and LUN MUST be provided by
+     * the target if the A bit is set to 1; otherwise, they are reserved.
+     * The Target Transfer Tag and LUN are copied by the initiator into the
+     * SNACK of type DataACK that it issues as a result of receiving a SCSI
+     * Data-In PDU with the A bit set to 1.\n
+     * The Target Transfer Tag values are not specified by this protocol,
+     * except that the value 0xFFFFFFFF is reserved and means that the
+     * Target Transfer Tag is not supplied.
+     */
+    uint32_t target_xfer_tag;
+
+    /// StatSN.
+    uint32_t stat_sn;
+
+    /// ExpCmdSN.
+
+    uint32_t exp_cmd_sn;
+
+    /// MaxCmdSN.
+    uint32_t max_cmd_sn;
+
+    /**
+     * @brief DataSN.
+     *
+     * For input (read) or bidirectional Data-In PDUs, the DataSN is the
+     * input PDU number within the data transfer for the command identified
+     * by the Initiator Task Tag.\n
+     * R2T and Data-In PDUs, in the context of bidirectional commands, share
+     * the numbering sequence.
+     */
+    uint32_t data_sn;
+
+    /**
+     * @brief Buffer Offset.
+     *
+     * The Buffer Offset field contains the offset of this PDU payload data
+     * within the complete data transfer. The sum of the buffer offset and
+     * length should not exceed the expected transfer length for the
+     * command.\n
+     * The order of data PDUs within a sequence is determined by
+     * DataPDUInOrder. When set to Yes, it means that PDUs have to be in
+     * increasing buffer offset order and overlays are forbidden.\n
+     * The ordering between sequences is determined by DataSequenceInOrder.
+     * When set to Yes, it means that sequences have to be in increasing
+     * buffer offset order and overlays are forbidden.
+     */
+    uint32_t buf_offset;
+
+    /// Residual Count or Reserved.
+    uint32_t res_cnt;
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
+
+    /// Data segment.
+    iscsi_ds_cmd_data ds_cmd_data;
+
+    /// Optional data digest.
+    iscsi_data_digest data_digest;
 } iscsi_scsi_data_in_response_packet;
 
-/* When an initiator has submitted a SCSI command with data that passes
-   from the initiator to the target (write), the target may specify
-   which blocks of data it is ready to receive. The target may request
-   that the data blocks be delivered in whichever order is convenient
-   for the target at that particular instant. This information is
-   passed from the target to the initiator in the Ready To Transfer
-   (R2T) PDU.
-
-   In order to allow write operations without an explicit initial R2T,
-   the initiator and target MUST have negotiated the key InitialR2T to
-   No during login.
-
-   An R2T MAY be answered with one or more SCSI Data-Out PDUs with a
-   matching Target Transfer Tag. If an R2T is answered with a single
-   Data-Out PDU, the buffer offset in the data PDU MUST be the same as
-   the one specified by the R2T, and the data length of the data PDU
-   MUST be the same as the Desired Data Transfer Length specified in the
-   R2T. If the R2T is answered with a sequence of data PDUs, the buffer
-   offset and length MUST be within the range of those specified by the
-   R2T, and the last PDU MUST have the F bit set to 1. If the last PDU
-   (marked with the F bit) is received before the Desired Data Transfer
-   Length is transferred, a target MAY choose to reject that PDU with
-   the "Protocol Error" reason code. DataPDUInOrder governs the
-   Data-Out PDU ordering. If DataPDUInOrder is set to Yes, the buffer
-   offsets and lengths for consecutive PDUs MUST form a continuous
-   non-overlapping range, and the PDUs MUST be sent in increasing offset
-   order.
-
-   The target may send several R2T PDUs. It therefore can have a number
-   of pending data transfers. The number of outstanding R2T PDUs is
-   limited by the value of the negotiated key MaxOutstandingR2T. Within
-   a task, outstanding R2Ts MUST be fulfilled by the initiator in the
-   order in which they were received.
-
-   R2T PDUs MAY also be used to recover Data-Out PDUs. Such an R2T
-   (Recovery-R2T) is generated by a target upon detecting the loss of
-   one or more Data-Out PDUs due to:
-
-      - Digest error
-
-      - Sequence error
-
-      - Sequence reception timeout
-
-   A Recovery-R2T carries the next unused R2TSN but requests part of or
-   the entire data burst that an earlier R2T (with a lower R2TSN) had
-   already requested.
-
-   DataSequenceInOrder governs the buffer offset ordering in consecutive
-   R2Ts. If DataSequenceInOrder is Yes, then consecutive R2Ts MUST
-   refer to continuous non-overlapping ranges, except for Recovery-R2Ts.
-*/
+/**
+ * @brief iSCSI Ready To Transfer packet data.
+ *
+ * When an initiator has submitted a SCSI command with data that passes
+ * from the initiator to the target (write), the target may specify
+ * which blocks of data it is ready to receive. The target may request
+ * that the data blocks be delivered in whichever order is convenient
+ * for the target at that particular instant. This information is
+ * passed from the target to the initiator in the Ready To Transfer
+ * (R2T) PDU.
+ *
+ * In order to allow write operations without an explicit initial R2T,
+ * the initiator and target MUST have negotiated the key InitialR2T to
+ * No during login.
+ *
+ * An R2T MAY be answered with one or more SCSI Data-Out PDUs with a
+ * matching Target Transfer Tag. If an R2T is answered with a single
+ * Data-Out PDU, the buffer offset in the data PDU MUST be the same as
+ * the one specified by the R2T, and the data length of the data PDU
+ * MUST be the same as the Desired Data Transfer Length specified in the
+ * R2T. If the R2T is answered with a sequence of data PDUs, the buffer
+ * offset and length MUST be within the range of those specified by the
+ * R2T, and the last PDU MUST have the F bit set to 1. If the last PDU
+ * (marked with the F bit) is received before the Desired Data Transfer
+ * Length is transferred, a target MAY choose to reject that PDU with
+ * the "Protocol Error" reason code. DataPDUInOrder governs the
+ * Data-Out PDU ordering. If DataPDUInOrder is set to Yes, the buffer
+ * offsets and lengths for consecutive PDUs MUST form a continuous
+ * non-overlapping range, and the PDUs MUST be sent in increasing offset
+ * order.
+ *
+ * The target may send several R2T PDUs. It therefore can have a number
+ * of pending data transfers. The number of outstanding R2T PDUs is
+ * limited by the value of the negotiated key MaxOutstandingR2T. Within
+ * a task, outstanding R2Ts MUST be fulfilled by the initiator in the
+ * order in which they were received.
+ *
+ * R2T PDUs MAY also be used to recover Data-Out PDUs. Such an R2T
+ * (Recovery-R2T) is generated by a target upon detecting the loss of
+ * one or more Data-Out PDUs due to:
+ *
+ *    - Digest error
+ *
+ *    - Sequence error
+ *
+ *    - Sequence reception timeout
+ *
+ * A Recovery-R2T carries the next unused R2TSN but requests part of or
+ * the entire data burst that an earlier R2T (with a lower R2TSN) had
+ * already requested.
+ *
+ * DataSequenceInOrder governs the buffer offset ordering in consecutive
+ * R2Ts. If DataSequenceInOrder is Yes, then consecutive R2Ts MUST
+ * refer to continuous non-overlapping ranges, except for Recovery-R2Ts.
+ */
 typedef struct __attribute__((packed)) iscsi_r2t_packet {
-    uint8_t opcode; // Always 0x31 according to specification (see above)
-    uint8_t flags; // Reserved for future usage
-    uint16_t reserved; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength, MUST be 0 for this PDU
-    uint8_t ds_len[3]; // DataSegmentLength, MUST be 0 0 for this PDU
-    uint64_t lun; // Logical Unit Number (LUN) or Reserved
-    uint32_t init_task_tag; // Initiator task tag
-    uint32_t target_xfer_tag; // Target transfer tag
-    uint32_t stat_sn; // The StatSN field will contain the next StatSN. The StatSN for this
-                      // connection is not advanced after this PDU is sent
-    uint32_t exp_cmd_sn; // ExpCmdSN
-    uint32_t max_cmd_sn; // MaxCmdSN
-    uint32_t data_sn; // DataSN
-    uint32_t r2t_sn; // R2TSN is the R2T PDU input PDU number within the command identified
-                     // by the Initiator Task Tag.
-                     // For bidirectional commands, R2T and Data-In PDUs share the input PDU
-                     // numbering sequence
-    uint32_t buf_offset; // Buffer Offset
-                         // The target therefore also specifies a buffer offset that
-                         // indicates the point at which the data transfer should begin, relative
-                         // to the beginning of the total data transfer
-    uint32_t des_data_xfer_len; // Desired Data Transfer Length
-                                // The target specifies how many bytes it wants the initiator to send
-                                // because of this R2T PDU. The target may request the data from the
-                                // initiator in several chunks, not necessarily in the original order of
-                                // the data. The Desired Data Transfer Length MUST NOT be 0 and MUST NOT
-                                // exceed MaxBurstLength
-    struct iscsi_header_digest hdr_digest; // Optional header digest
+    /// Always 0x31 according to iSCSI specification.
+    uint8_t opcode;
+
+    /// Reserved for future usage (must be always 0x80 for now).
+    int8_t flags;
+
+    /// Reserved for future usage, always MUST be 0 for now.
+    uint16_t reserved;
+
+    /// TotalAHSLength, MUST be 0 for this PDU.
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength, MUST be 0 0 for this PDU.
+    uint8_t ds_len[3];
+
+    /// Logical Unit Number (LUN) or Reserved.
+    uint64_t lun;
+
+    /// Initiator Task Tag (ITT).
+    uint32_t init_task_tag;
+
+    /// Target Transfer Tag (TTT).
+    uint32_t target_xfer_tag;
+
+    /// The StatSN field will contain the next StatSN. The StatSN for this connection is not advanced after this PDU is sent.
+    uint32_t stat_sn;
+
+    /// ExpCmdSN.
+    uint32_t exp_cmd_sn;
+
+    /// MaxCmdSN.
+    uint32_t max_cmd_sn;
+
+    /// DataSN.
+    uint32_t data_sn;
+
+    /// Ready To Transfer Sequence Number (R2TSN) is the R2T PDU input PDU number within the command identified by the Initiator Task Tag. For bidirectional commands, R2T and Data-In PDUs share the input PDU numbering sequence.
+    uint32_t r2t_sn;
+
+    /**
+     * @brief Buffer Offset.
+     *
+     * The target therefore also specifies a buffer offset that indicates
+     * the point at which the data transfer should begin, relative to the
+     * beginning of the total data transfer.
+     */
+    uint32_t buf_offset;
+
+    /**
+     * @brief Desired Data Transfer Length.
+     *
+     * The target specifies how many bytes it wants the initiator to send
+     * because of this R2T PDU. The target may request the data from the
+     * initiator in several chunks, not necessarily in the original order of
+     * the data. The Desired Data Transfer Length MUST NOT be 0 and MUST NOT
+     * exceed MaxBurstLength.
+     */
+    uint32_t des_data_xfer_len;
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
 } iscsi_r2t_packet;
 
-#define ISCSI_ASYNC_MSG_EVENT_SCSI_ASYNC_EVENT    0x00 // (SCSI Async Event) - a SCSI asynchronous event is reported in
-                                                       // the sense data. Sense Data that accompanies the report, in
-                                                       // the data segment, identifies the condition. The sending of a
-                                                       // SCSI event ("asynchronous event reporting" in SCSI
-                                                       // terminology) is dependent on the target support for SCSI
-                                                       // asynchronous event reporting as indicated in the
-                                                       // standard INQUIRY data. Its use may be enabled by
-                                                       // parameters in the SCSI Control mode page
-#define ISCSI_ASYNC_MSG_EVENT_LOGOUT_REQUEST      0x01 // (Logout Request) - the target requests Logout. This Async
-                                                       // Message MUST be sent on the same connection as the one
-                                                       // requesting to be logged out. The initiator MUST honor this
-                                                       // request by issuing a Logout as early as possible but no later
-                                                       // than Parameter3 seconds. The initiator MUST send a Logout
-                                                       // with a reason code of "close the connection" OR "close the
-                                                       // session" to close all the connections. Once this message is
-                                                       // received, the initiator SHOULD NOT issue new iSCSI commands on
-                                                       // the connection to be logged out. The target MAY reject any
-                                                       // new I/O requests that it receives after this message with the
-                                                       // reason code "Waiting for Logout". If the initiator does not
-                                                       // log out in Parameter3 seconds, the target should send an Async
-                                                       // PDU with iSCSI event code "Dropped the connection" if possible
-                                                       // or simply terminate the transport connection. Parameter1 and
-                                                       // Parameter2 are reserved
-#define ISCSI_ASYNC_MSG_EVENT_CONNECT_DROP_NOTIFY 0x02 // (Connection Drop Notification) - the target indicates that it
-                                                       // will drop the connection.
-                                                       // The Parameter1 field indicates the CID of the connection that
-                                                       // is going to be dropped.
-                                                       // The Parameter2 field (Time2Wait) indicates, in seconds, the
-                                                       // minimum time to wait before attempting to reconnect or
-                                                       // reassign.
-                                                       // The Parameter3 field (Time2Retain) indicates the maximum time
-                                                       // allowed to reassign commands after the initial wait (in
-                                                       // Parameter2).
-                                                       // If the initiator does not attempt to reconnect and/or reassign
-                                                       // the outstanding commands within the time specified by
-                                                       // Parameter3, or if Parameter3 is 0, the target will terminate
-                                                       // all outstanding commands on this connection. In this case, no
-                                                       // other responses should be expected from the target for the
-                                                       // outstanding commands on this connection.
-                                                       // A value of 0 for Parameter2 indicates that reconnect can be
-                                                       // attempted immediately
-#define ISCSI_ASYNC_MSG_EVENT_SESSION_DROP_NOTIFY 0x03 // (Session Drop Notification) - the target indicates that it
-                                                       // will drop all the connections of this session.
-                                                       // The Parameter1 field is reserved.
-                                                       // The Parameter2 field (Time2Wait) indicates, in seconds, the
-                                                       // minimum time to wait before attempting to reconnect.
-                                                       // The Parameter3 field (Time2Retain) indicates the maximum time
-                                                       // allowed to reassign commands after the initial wait (in
-                                                       // Parameter2).
-                                                       // If the initiator does not attempt to reconnect and/or reassign
-                                                       // the outstanding commands within the time specified by
-                                                       // Parameter3, or if Parameter3 is 0, the session is terminated.
-                                                       // In this case, the target will terminate all outstanding
-                                                       // commands in this session; no other responses should be
-                                                       // expected from the target for the outstanding commands in this
-                                                       // session. A value of 0 for Parameter2 indicates that reconnect
-                                                       // can be attempted immediately
-#define ISCSI_ASYNC_MSG_EVENT_NEGOTIATION_REQUEST 0x04 // (Negotiation Request) - the target requests parameter
-                                                       // negotiation on this connection. The initiator MUST honor this
-                                                       // request by issuing a Text Request (that can be empty) on the
-                                                       // same connection as early as possible, but no later than
-                                                       // Parameter3 seconds, unless a Text Request is already pending
-                                                       // on the connection, or by issuing a Logout Request. If the
-                                                       // initiator does not issue a Text Request, the target may
-                                                       // reissue the Asynchronous Message requesting parameter
-                                                       // negotiation
-#define ISCSI_ASYNC_MSG_EVENT_TASK_TERMINATION    0x05 // (Task Termination) - all active tasks for a LU with a matching
-                                                       // LUN field in the Async Message PDU are being terminated. The
-                                                       // receiving initiator iSCSI layer MUST respond to this message
-                                                       // by taking the following steps, in order:
-                                                       // - Stop Data-Out transfers on that connection for all active
-                                                       //   TTTs for the affected LUN quoted in the Async Message PDU.
-                                                       // - Acknowledge the StatSN of the Async Message PDU via a
-                                                       //   NOP-Out PDU with ITT=0xFFFFFFFF (i.e., non-ping flavor),
-                                                       //   while copying the LUN field from the Async Message to
-                                                       //   NOP-Out.
-                                                       // This value of AsyncEvent, however, MUST NOT be used on an
-                                                       // iSCSI session unless the new TaskReporting text key was
-                                                       // negotiated to FastAbort on the session
-#define ISCSI_ASYNC_MSG_EVENT_VENDOR_FIRST        0xF8 // First vendor-specific iSCSI event. The AsyncVCode details the
-                                                       // vendor code, and data MAY accompany the report
-#define ISCSI_ASYNC_MSG_EVENT_VENDOR_LAST         0xFF // Last vendor-specific iSCSI event. The AsyncVCode details the
-                                                       // vendor code, and data MAY accompany the report
-
-/* An Asynchronous Message may be sent from the target to the initiator
-   without corresponding to a particular command. The target specifies
-   the reason for the event and sense data.
-   Some Asynchronous Messages are strictly related to iSCSI, while
-   others are related to SCSI
-*/
+
+/**
+ * @brief SCSI Asynchronous Message Event: SCSI Async Event.
+ *
+ * A SCSI asynchronous event is reported in the sense data.
+ * Sense Data that accompanies the report, in the data
+ * segment, identifies the condition. The sending of a
+ * SCSI event ("asynchronous event reporting" in SCSI
+ * terminology) is dependent on the target support for SCSI
+ * asynchronous event reporting as indicated in the
+ * standard INQUIRY data. Its use may be enabled by
+ * parameters in the SCSI Control mode page.
+ */
+#define ISCSI_ASYNC_MSG_EVENT_SCSI_ASYNC_EVENT    0x00
+
+/**
+ * @brief SCSI Asynchronous Message Event: Logout Request.
+ *
+ * The target requests Logout. This Async Message MUST
+ * be sent on the same connection as the one requesting
+ * to be logged out. The initiator MUST honor this request
+ * by issuing a Logout as early as possible but no later
+ * than Parameter3 seconds. The initiator MUST send a Logout
+ * with a reason code of "close the connection" OR "close the
+ * session" to close all the connections. Once this message is
+ * received, the initiator SHOULD NOT issue new iSCSI commands on
+ * the connection to be logged out. The target MAY reject any
+ * new I/O requests that it receives after this message with the
+ * reason code "Waiting for Logout". If the initiator does not
+ * log out in Parameter3 seconds, the target should send an Async
+ * PDU with iSCSI event code "Dropped the connection" if possible
+ * or simply terminate the transport connection. Parameter1 and
+ * Parameter2 are reserved.
+ */
+#define ISCSI_ASYNC_MSG_EVENT_LOGOUT_REQUEST      0x01
+
+/**
+ * @brief SCSI Asynchronous Message Event: Connection Drop Notification.
+ *
+ * The target indicates that it will drop the connection.
+ * The Parameter1 field indicates the CID of the connection that
+ * is going to be dropped.\n
+ * The Parameter2 field (Time2Wait) indicates, in seconds, the
+ * minimum time to wait before attempting to reconnect or
+ * reassign.\n
+ * The Parameter3 field (Time2Retain) indicates the maximum time
+ * allowed to reassign commands after the initial wait (in
+ * Parameter2).\n
+ * If the initiator does not attempt to reconnect and/or reassign
+ * the outstanding commands within the time specified by
+ * Parameter3, or if Parameter3 is 0, the target will terminate
+ * all outstanding commands on this connection. In this case, no
+ * other responses should be expected from the target for the
+ * outstanding commands on this connection.\n
+ * A value of 0 for Parameter2 indicates that reconnect can be
+ * attempted immediately.
+ */
+#define ISCSI_ASYNC_MSG_EVENT_CONNECT_DROP_NOTIFY 0x02
+
+/**
+ * @brief SCSI Asynchronous Message Event: Session Drop Notification.
+ *
+ * The target indicates that it will drop all the connections
+ * of this session.\n
+ * The Parameter1 field is reserved.\n
+ * The Parameter2 field (Time2Wait) indicates, in seconds, the
+ * minimum time to wait before attempting to reconnect.\n
+ * The Parameter3 field (Time2Retain) indicates the maximum time
+ * allowed to reassign commands after the initial wait (in
+ * Parameter2).\n
+ * If the initiator does not attempt to reconnect and/or reassign
+ * the outstanding commands within the time specified by
+ * Parameter3, or if Parameter3 is 0, the session is terminated.\n
+ * In this case, the target will terminate all outstanding
+ * commands in this session; no other responses should be
+ * expected from the target for the outstanding commands in this
+ * session. A value of 0 for Parameter2 indicates that reconnect
+ * can be attempted immediately.
+ */
+#define ISCSI_ASYNC_MSG_EVENT_SESSION_DROP_NOTIFY 0x03
+
+/**
+ * @brief SCSI Asynchronous Message Event: Negotiation Request.
+ *
+ * The target requests parameter negotiation on this connection.
+ * The initiator MUST honor this request by issuing a Text
+ * Request (that can be empty) on the same connection as early
+ * as possible, but no later than Parameter3 seconds, unless a
+ * Text Request is already pending on the connection, or by
+ * issuing a Logout Request. If the initiator does not issue a
+ * Text Request, the target may reissue the Asynchronous Message
+ * requesting parameter negotiation.
+ */
+#define ISCSI_ASYNC_MSG_EVENT_NEGOTIATION_REQUEST 0x04
+
+/**
+ * @brief SCSI Asynchronous Message Event: Task Termination.
+ *
+ * All active tasks for a LU with a matching LUN field in the
+ * Async Message PDU are being terminated. The receiving
+ * initiator iSCSI layer MUST respond to this message by
+ * taking the following steps, in order:
+ * - Stop Data-Out transfers on that connection for all active
+ *   TTTs for the affected LUN quoted in the Async Message PDU.
+ * - Acknowledge the StatSN of the Async Message PDU via a
+ *   NOP-Out PDU with ITT=0xFFFFFFFF (i.e., non-ping flavor),
+ *   while copying the LUN field from the Async Message to
+ *   NOP-Out.
+ * This value of AsyncEvent, however, MUST NOT be used on an
+ * iSCSI session unless the new TaskReporting text key was
+ * negotiated to FastAbort on the session.
+ */
+#define ISCSI_ASYNC_MSG_EVENT_TASK_TERMINATION    0x05
+
+/// SCSI Asynchronous Message Event: First vendor-specific iSCSI event. The AsyncVCode details the vendor code, and data MAY accompany the report.
+#define ISCSI_ASYNC_MSG_EVENT_VENDOR_FIRST        0xF8
+
+/// SCSI Asynchronous Message Event: Last vendor-specific iSCSI event. The AsyncVCode details the vendor code, and data MAY accompany the report.
+#define ISCSI_ASYNC_MSG_EVENT_VENDOR_LAST         0xFF
+
+/**
+ * @brief iSCSI Asynchronous Message packet data.
+ *
+ * An Asynchronous Message may be sent from the target to the initiator
+ * without corresponding to a particular command. The target specifies
+ * the reason for the event and sense data.\n
+ * Some Asynchronous Messages are strictly related to iSCSI, while
+ * others are related to SCSI
+ */
 typedef struct __attribute__((packed)) iscsi_async_msg_packet {
-    uint8_t opcode; // Always 0x32 according to specification (see above
-    uint8_t flags; // Reserved for future usage
-    uint16_t reserved; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength, MUST be 0 for this PDU
-    uint8_t ds_len[3]; // DataSegmentLength, MUST be 0 0 for this PDU
-    uint64_t lun; // The LUN field MUST be valid if AsyncEvent is 0. Otherwise, this
-                  // field is reserved
-    uint32_t tag; // Tag (always 0xFFFFFFFF for now)
-    uint32_t reserved2; // Reserved for future usage
-    uint32_t stat_sn; // StatSN
-                      // The StatSN counts this PDU as an acknowledgeable event (the StatSN is
-                      // advanced), which allows for initiator and target state synchronization.
-    uint32_t exp_cmd_sn; // ExpCmdSN
-    uint32_t max_cmd_sn; // MaxCmdSN
-    uint8_t async_event; // AsyncEvent
-    uint8_t async_vcode; // AsyncVCode is a vendor-specific detail code that is only valid if the
-                         // AsyncEvent field indicates a vendor-specific event. Otherwise, it is
-                         // reserved
-    uint16_t param_1; // Parameter1 or Reserved
-    uint16_t param_2; // Parameter2 or Reserved
-    uint16_t param_3; // Parameter3 or Reserved
-    uint32_t reserved3; // Reserved for future usage
-    struct iscsi_header_digest hdr_digest; // Optional header digest
-    struct iscsi_ds_cmd_data ds_cmd_data; // Data segment
-    struct iscsi_data_digest data_digest; // Optional data digest
-} iscsi_async_msg_packet;
+    /// Always 0x32 according to iSCSI specification.
+    uint8_t opcode;
 
-/* For a SCSI event, this data accompanies the report in the data
-   segment and identifies the condition.
+    /// Reserved for future usage (must be always 0x80 for now).
+    int8_t flags;
 
-   For an iSCSI event, additional vendor-unique data MAY accompany the
-   Async event. Initiators MAY ignore the data when not understood,
-   while processing the rest of the PDU.
+    /// Reserved for future usage, always MUST be 0.
+    uint16_t reserved;
 
-   If the DataSegmentLength is not 0, the format of the DataSegment is
-   as follows:
-*/
+    /// TotalAHSLength, MUST be 0 for this PDU.
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength, MUST be 0 0 for this PDU.
+    uint8_t ds_len[3];
+
+    /// The LUN field MUST be valid if AsyncEvent is 0. Otherwise, this field is reserved.
+    uint64_t lun;
+
+    /// Tag (always 0xFFFFFFFF for now).
+    uint32_t tag;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved2;
+
+    /**
+     * @brief StatSN.
+     *
+     * The StatSN counts this PDU as an acknowledgeable event (the StatSN is
+     * advanced), which allows for initiator and target state synchronization.
+     */
+    uint32_t stat_sn;
+
+    /// ExpCmdSN.
+    uint32_t exp_cmd_sn;
+
+    /// MaxCmdSN.
+    uint32_t max_cmd_sn;
+
+    /// AsyncEvent.
+    uint8_t async_event;
+
+    /// AsyncVCode is a vendor-specific detail code that is only valid if the AsyncEvent field indicates a vendor-specific event. Otherwise, it is reserved.
+    uint8_t async_vcode;
+
+    /// Parameter1 or Reserved.
+    uint16_t param_1;
+
+    /// Parameter2 or Reserved.
+    uint16_t param_2;
+
+    /// Parameter3 or Reserved.
+    uint16_t param_3;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved3;
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
+
+    /// Data segment.
+    iscsi_ds_cmd_data ds_cmd_data;
+
+    /// Optional data digest.
+    iscsi_data_digest data_digest;
+} iscsi_async_msg_packet;
+
+
+/**
+ * @brief iSCSI Sense Event data packet.
+ *
+ * For a SCSI event, this data accompanies the report in the data
+ * segment and identifies the condition.
+ *
+ * For an iSCSI event, additional vendor-unique data MAY accompany the
+ * Async event. Initiators MAY ignore the data when not understood,
+ * while processing the rest of the PDU.
+ *
+ * If the DataSegmentLength is not 0, the format of the DataSegment is
+ * as follows:
+ */
 typedef struct __attribute__((packed)) iscsi_sense_event_data_packet {
-    uint16_t sense_len; // SenseLength
-                        // This is the length of Sense Data. When the Sense Data field is empty
-                        // (e.g., the event is not a SCSI event), SenseLength is 0
-    uint16_t sense_data[0]; // Sense Data
-    uint16_t event_data[0]; // iSCSI Event Data
+    /**
+     * @brief SenseLength.
+     *
+     * This is the length of Sense Data. When the Sense Data field is empty
+     * (e.g., the event is not a SCSI event), SenseLength is 0.
+     */
+    uint16_t sense_len;
+
+    /// Sense Data.
+    uint16_t sense_data[0];
+
+    /// iSCSI Event Data.
+    uint16_t event_data[0];
 } iscsi_sense_event_data_packet;
 
-#define ISCSI_TEXT_REQ_FLAGS_CONTINUE (1 << 6) // (C) When set to 1, this bit indicates that the text (set of key=value
-                                               // pairs) in this Text Request is not complete (it will be continued on
-                                               // subsequent Text Requests); otherwise, it indicates that this Text
-                                               // Request ends a set of key=value pairs. A Text Request with the C bit
-                                               // set to 1 MUST have the F bit set to 0.
-#define ISCSI_TEXT_REQ_FLAGS_FINAL    (1 << 7) // (F) When set to 1, this bit indicates that this is the last or only Text
-                                               // Request in a sequence of Text Requests; otherwise, it indicates that
-                                               // more Text Requests will follow.
-
-/* The Text Request is provided to allow for the exchange of information
-   and for future extensions. It permits the initiator to inform a
-   target of its capabilities or request some special operations.
-
-   An initiator MUST NOT have more than one outstanding Text Request on
-   a connection at any given time.
-
-   On a connection failure, an initiator must either explicitly abort
-   any active allegiant text negotiation task or cause such a task to be
-   implicitly terminated by the target.
-*/
+
+/**
+ * @brief Text Request flags: Continue.
+ *
+ * (C) When set to 1, this bit indicates that the text (set of key=value
+ * pairs) in this Text Request is not complete (it will be continued on
+ * subsequent Text Requests); otherwise, it indicates that this Text
+ * Request ends a set of key=value pairs. A Text Request with the C bit
+ * set to 1 MUST have the F bit set to 0.
+ */
+#define ISCSI_TEXT_REQ_FLAGS_CONTINUE (1 << 6)
+
+/**
+ * @brief Text Request flags: Final.
+ *
+ * (F) When set to 1, this bit indicates that this is the last or only Text
+ * Request in a sequence of Text Requests; otherwise, it indicates that
+ * more Text Requests will follow.
+ */
+#define ISCSI_TEXT_REQ_FLAGS_FINAL    (1 << 7)
+
+/**
+ * @brief iSCSI Text Request packet data.
+ *
+ * The Text Request is provided to allow for the exchange of information
+ * and for future extensions. It permits the initiator to inform a
+ * target of its capabilities or request some special operations.
+ *
+ * An initiator MUST NOT have more than one outstanding Text Request on
+ * a connection at any given time.
+ *
+ * On a connection failure, an initiator must either explicitly abort
+ * any active allegiant text negotiation task or cause such a task to be
+ * implicitly terminated by the target.
+ */
 typedef struct __attribute__((packed)) iscsi_text_req_packet {
-    uint8_t opcode; // Always 0x04 according to specification (see above)
-    int8_t flags; // Text request flags (see above)
-    uint16_t reserved; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength
-    uint8_t ds_len[3]; // DataSegmentLength
-    uint64_t lun; // Logical Unit Number (LUN) or Reserved
-    uint32_t init_task_tag; // This is the initiator-assigned identifier for this Text Request. If
-                            // the command is sent as part of a sequence of Text Requests and
-                            // responses, the Initiator Task Tag MUST be the same for all the
-                            // requests within the sequence (similar to linked SCSI commands). The
-                            // I bit for all requests in a sequence also MUST be the same
-    uint32_t target_xfer_tag; // When the Target Transfer Tag is set to the reserved value 0xFFFFFFFF,
-                              // it tells the target that this is a new request, and the target resets
-                              // any internal state associated with the Initiator Task Tag (resets the
-                              // current negotiation state).
-                              // The target sets the Target Transfer Tag in a Text Response to a value
-                              // other than the reserved value 0xFFFFFFFF whenever it indicates that
-                              // it has more data to send or more operations to perform that are
-                              // associated with the specified Initiator Task Tag. It MUST do so
-                              // whenever it sets the F bit to 0 in the response. By copying the
-                              // Target Transfer Tag from the response to the next Text Request, the
-                              // initiator tells the target to continue the operation for the specific
-                              // Initiator Task Tag. The initiator MUST ignore the Target Transfer
-                              // Tag in the Text Response when the F bit is set to 1.
-                              // This mechanism allows the initiator and target to transfer a large
-                              // amount of textual data over a sequence of text-command/text-response
-                              // exchanges or to perform extended negotiation sequences.
-                              // If the Target Transfer Tag is not 0xFFFFFFFF, the LUN field MUST be
-                              // sent by the target in the Text Response.
-                              // A target MAY reset its internal negotiation state if an exchange is
-                              // stalled by the initiator for a long time or if it is running out of
-                              // resources.
-                              // Long Text Responses are handled as shown in the following example:
-                              //    I->T Text SendTargets=All (F = 1, TTT = 0xFFFFFFFF)
-                              //    T->I Text <part 1> (F = 0, TTT = 0x12345678)
-                              //    I->T Text <empty> (F = 1, TTT = 0x12345678)
-                              //    T->I Text <part 2> (F = 0, TTT = 0x12345678)
-                              //    I->T Text <empty> (F = 1, TTT = 0x12345678)
-                              //    ...
-                              //    T->I Text <part n> (F = 1, TTT = 0xFFFFFFFF)
-    uint32_t cmd_sn; // CmdSN
-    uint32_t exp_stat_sn; // ExpStatSN
-    uint64_t reserved2[2]; // Reserved for future usage
-    struct iscsi_header_digest hdr_digest; // Optional header digest
-    struct iscsi_ds_cmd_data ds_cmd_data; // Data segment
-                                          // The data lengths of a Text Request MUST NOT exceed the iSCSI target
-                                          // MaxRecvDataSegmentLength (a parameter that is negotiated per
-                                          // connection and per direction).
-                                          // A key=value pair can span Text Request or Text Response boundaries.
-                                          // A key=value pair can start in one PDU and continue on the next. In
-                                          // other words, the end of a PDU does not necessarily signal the end of
-                                          // a key=value pair.
-                                          // The target responds by sending its response back to the initiator.
-                                          // The response text format is similar to the request text format. The
-                                          // Text Response MAY refer to key=value pairs presented in an earlier
-                                          // Text Request, and the text in the request may refer to earlier
-                                          // responses.
-                                          // Text operations are usually meant for parameter setting/negotiations
-                                          // but can also be used to perform some long-lasting operations
-    struct iscsi_data_digest data_digest; // Optional data digest
+    /// Always 0x04 according to iSCSI specification.
+    uint8_t opcode;
+
+    /// Text request flags.
+    int8_t flags;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint16_t reserved;
+
+    /// TotalAHSLength.
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength.
+    uint8_t ds_len[3];
+
+    /// Logical Unit Number (LUN) or Reserved.
+    uint64_t lun;
+
+    /**
+     * @brief Initiator Task Tag (ITT).
+     *
+     * This is the initiator-assigned identifier for this Text Request. If
+     * the command is sent as part of a sequence of Text Requests and
+     * responses, the Initiator Task Tag MUST be the same for all the
+     * requests within the sequence (similar to linked SCSI commands). The
+     * I bit for all requests in a sequence also MUST be the same.
+     */
+    uint32_t init_task_tag;
+
+    /**
+     * @brief Target Transfer Tag (TTT).
+     *
+     * When the Target Transfer Tag is set to the reserved value 0xFFFFFFFF,
+     * it tells the target that this is a new request, and the target resets
+     * any internal state associated with the Initiator Task Tag (resets the
+     * current negotiation state).\n
+     * The target sets the Target Transfer Tag in a Text Response to a value
+     * other than the reserved value 0xFFFFFFFF whenever it indicates that
+     * it has more data to send or more operations to perform that are
+     * associated with the specified Initiator Task Tag. It MUST do so
+     * whenever it sets the F bit to 0 in the response. By copying the
+     * Target Transfer Tag from the response to the next Text Request, the
+     * initiator tells the target to continue the operation for the specific
+     * Initiator Task Tag. The initiator MUST ignore the Target Transfer
+     * Tag in the Text Response when the F bit is set to 1.\n
+     * This mechanism allows the initiator and target to transfer a large
+     * amount of textual data over a sequence of text-command/text-response
+     * exchanges or to perform extended negotiation sequences.\n
+     * If the Target Transfer Tag is not 0xFFFFFFFF, the LUN field MUST be
+     * sent by the target in the Text Response.\n
+     * A target MAY reset its internal negotiation state if an exchange is
+     * stalled by the initiator for a long time or if it is running out of
+     * resources.\n
+     * Long Text Responses are handled as shown in the following example:\n
+     * @verbatim
+     *    I->T Text SendTargets=All (F = 1, TTT = 0xFFFFFFFF)
+     *    T->I Text <part 1> (F = 0, TTT = 0x12345678)
+     *    I->T Text <empty> (F = 1, TTT = 0x12345678)
+     *    T->I Text <part 2> (F = 0, TTT = 0x12345678)
+     *    I->T Text <empty> (F = 1, TTT = 0x12345678)
+     *    ...
+     *    T->I Text <part n> (F = 1, TTT = 0xFFFFFFFF)
+     * @endverbatim
+     */
+    uint32_t target_xfer_tag;
+
+    /// CmdSN.
+    uint32_t cmd_sn;
+
+    /// ExpStatSN.
+    uint32_t exp_stat_sn;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint64_t reserved2[2];
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
+
+    /**
+     * @brief Data segment.
+     *
+     * The data lengths of a Text Request MUST NOT exceed the iSCSI target
+     * MaxRecvDataSegmentLength (a parameter that is negotiated per
+     * connection and per direction).\n
+     * A key=value pair can span Text Request or Text Response boundaries.
+     * A key=value pair can start in one PDU and continue on the next. In
+     * other words, the end of a PDU does not necessarily signal the end of
+     * a key=value pair.\n
+     * The target responds by sending its response back to the initiator.
+     * The response text format is similar to the request text format. The
+     * Text Response MAY refer to key=value pairs presented in an earlier
+     * Text Request, and the text in the request may refer to earlier
+     * responses.\n
+     * Text operations are usually meant for parameter setting/negotiations
+     * but can also be used to perform some long-lasting operations.
+     */
+    iscsi_ds_cmd_data ds_cmd_data;
+
+    /// Optional data digest.
+    iscsi_data_digest data_digest;
 } iscsi_text_req_packet;
 
-#define ISCSI_TEXT_RESPONSE_FLAGS_CONTINUE (1 << 6) // (C) When set to 1, this bit indicates that the text (set of key=value
-                                                    // pairs) in this Text Response is not complete (it will be continued on
-                                                    // subsequent Text Responses); otherwise, it indicates that this Text
-                                                    // Response ends a set of key=value pairs. A Text Response with the
-                                                    // C bit set to 1 MUST have the F bit set to 0
-#define ISCSI_TEXT_RESPONSE_FLAGS_FINAL    (1 << 7) // (F) When set to 1, in response to a Text Request with the Final bit set
-                                                    // to 1, the F bit indicates that the target has finished the whole
-                                                    // operation. Otherwise, if set to 0 in response to a Text Request with
-                                                    // the Final Bit set to 1, it indicates that the target has more work to
-                                                    // do (invites a follow-on Text Request). A Text Response with the
-                                                    // F bit set to 1 in response to a Text Request with the F bit set to 0
-                                                    // is a protocol error.
-                                                    // A Text Response with the F bit set to 1 MUST NOT contain key=value
-                                                    // pairs that may require additional answers from the initiator.
-                                                    // A Text Response with the F bit set to 1 MUST have a Target Transfer
-                                                    // Tag field set to the reserved value 0xFFFFFFFF.
-                                                    // A Text Response with the F bit set to 0 MUST have a Target Transfer
-                                                    // Tag field set to a value other than the reserved value 0xFFFFFFFF
-
-/* The Text Response PDU contains the target's responses to the
-   initiator's Text Request. The format of the Text field matches that
-   of the Text Request.
-*/
+
+/**
+ * @brief Text Response flags: Continue.
+ *
+ * (C) When set to 1, this bit indicates that the text (set of key=value
+ * pairs) in this Text Response is not complete (it will be continued on
+ * subsequent Text Responses); otherwise, it indicates that this Text
+ * Response ends a set of key=value pairs. A Text Response with the
+ * C bit set to 1 MUST have the F bit set to 0.
+ */
+#define ISCSI_TEXT_RESPONSE_FLAGS_CONTINUE (1 << 6)
+
+/**
+ * @brief Text Response flags: Final.
+ *
+ * (F) When set to 1, in response to a Text Request with the Final bit set
+ * to 1, the F bit indicates that the target has finished the whole
+ * operation. Otherwise, if set to 0 in response to a Text Request with
+ * the Final Bit set to 1, it indicates that the target has more work to
+ * do (invites a follow-on Text Request). A Text Response with the
+ * F bit set to 1 in response to a Text Request with the F bit set to 0
+ * is a protocol error.\n
+ * A Text Response with the F bit set to 1 MUST NOT contain key=value
+ * pairs that may require additional answers from the initiator.
+ * A Text Response with the F bit set to 1 MUST have a Target Transfer
+ * Tag field set to the reserved value 0xFFFFFFFF.\n
+ * A Text Response with the F bit set to 0 MUST have a Target Transfer
+ * Tag field set to a value other than the reserved value 0xFFFFFFFF.
+ */
+#define ISCSI_TEXT_RESPONSE_FLAGS_FINAL    (1 << 7)
+
+/**
+ * @brief iSCSI Text Response packet data.
+ *
+ * The Text Response PDU contains the target's responses to the
+ * initiator's Text Request. The format of the Text field matches that
+ * of the Text Request.
+ */
 typedef struct __attribute__((packed)) iscsi_text_response_packet {
-    uint8_t opcode; // Always 0x24 according to specification (see above)
-    int8_t flags; // Text response flags (see above)
-    uint16_t reserved; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength
-    uint8_t ds_len[3]; // DataSegmentLength
-    uint64_t lun; // Logical Unit Number (LUN) or Reserved
-    uint32_t init_task_tag; // The Initiator Task Tag matches the tag used in the initial Text Request
-    uint32_t target_xfer_tag; // When a target has more work to do (e.g., cannot transfer all the
-                              // remaining text data in a single Text Response or has to continue the
-                              // negotiation) and has enough resources to proceed, it MUST set the
-                              // Target Transfer Tag to a value other than the reserved value
-                              // 0xFFFFFFFF. Otherwise, the Target Transfer Tag MUST be set to
-                              // 0xFFFFFFFF.
-                              // When the Target Transfer Tag is not 0xFFFFFFFF, the LUN field may be
-                              // significant.
-                              // The initiator MUST copy the Target Transfer Tag and LUN in its next
-                              // request to indicate that it wants the rest of the data.
-                              // When the target receives a Text Request with the Target Transfer Tag
-                              // set to the reserved value 0xFFFFFFFF, it resets its internal
-                              // information (resets state) associated with the given Initiator Task
-                              // Tag (restarts the negotiation).
-                              // When a target cannot finish the operation in a single Text Response
-                              // and does not have enough resources to continue, it rejects the Text
-                              // Request with the appropriate Reject code.
-                              // A target may reset its internal state associated with an Initiator
-                              // Task Tag (the current negotiation state) as expressed through the
-                              // Target Transfer Tag if the initiator fails to continue the exchange
-                              // for some time. The target may reject subsequent Text Requests with
-                              // the Target Transfer Tag set to the "stale" value
-    uint32_t stat_sn; // StatSN. The target StatSN variable is advanced by each Text Response sent
-    uint32_t exp_cmd_sn; // ExpCmdSN
-    uint32_t max_cmd_sn; // MaxCmdSN
-    uint64_t reserved2[2]; // Reserved for future usage
-    struct iscsi_header_digest hdr_digest; // Optional header digest
-    struct iscsi_ds_cmd_data ds_cmd_data; // Data segment
-                                          // The data lengths of a Text Response MUST NOT exceed the iSCSI
-                                          // initiator MaxRecvDataSegmentLength (a parameter that is negotiated
-                                          // per connection and per direction).
-                                          // The text in the Text Response Data is governed by the same rules as
-                                          // the text in the Text Request Data.
-                                          // Although the initiator is the requesting party and controls the
-                                          // request-response initiation and termination, the target can offer
-                                          // key=value pairs of its own as part of a sequence and not only in
-                                          // response to the initiator
-    struct iscsi_data_digest data_digest; // Optional data digest
+    /// Always 0x24 according to iSCSI specification.
+    uint8_t opcode;
+
+    /// Text response flags.
+    int8_t flags;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint16_t reserved;
+
+    /// TotalAHSLength.
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength.
+    uint8_t ds_len[3];
+
+    /// Logical Unit Number (LUN) or Reserved.
+    uint64_t lun;
+
+    /// The Initiator Task Tag matches the tag used in the initial Text Request.
+    uint32_t init_task_tag;
+
+    /**
+     * @brief Target Transfer Tag (TTT).
+     *
+     * When a target has more work to do (e.g., cannot transfer all the
+     * remaining text data in a single Text Response or has to continue the
+     * negotiation) and has enough resources to proceed, it MUST set the
+     * Target Transfer Tag to a value other than the reserved value
+     * 0xFFFFFFFF. Otherwise, the Target Transfer Tag MUST be set to
+     * 0xFFFFFFFF.\n
+     * When the Target Transfer Tag is not 0xFFFFFFFF, the LUN field may be
+     * significant.\n
+     * The initiator MUST copy the Target Transfer Tag and LUN in its next
+     * request to indicate that it wants the rest of the data.\n
+     * When the target receives a Text Request with the Target Transfer Tag
+     * set to the reserved value 0xFFFFFFFF, it resets its internal
+     * information (resets state) associated with the given Initiator Task
+     * Tag (restarts the negotiation).\n
+     * When a target cannot finish the operation in a single Text Response
+     * and does not have enough resources to continue, it rejects the Text
+     * Request with the appropriate Reject code.\n
+     * A target may reset its internal state associated with an Initiator
+     * Task Tag (the current negotiation state) as expressed through the
+     * Target Transfer Tag if the initiator fails to continue the exchange
+     * for some time. The target may reject subsequent Text Requests with
+     * the Target Transfer Tag set to the "stale" value.
+     */
+    uint32_t target_xfer_tag;
+
+    /// StatSN. The target StatSN variable is advanced by each Text Response sent.
+    uint32_t stat_sn;
+
+    /// ExpCmdSN.
+    uint32_t exp_cmd_sn;
+
+    /// MaxCmdSN.
+    uint32_t max_cmd_sn;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint64_t reserved2[2];
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
+
+    /**
+     * @brief Data segment.
+     *
+     * The data lengths of a Text Response MUST NOT exceed the iSCSI
+     * initiator MaxRecvDataSegmentLength (a parameter that is negotiated
+     * per connection and per direction).\n
+     * The text in the Text Response Data is governed by the same rules as
+     * the text in the Text Request Data.\n
+     * Although the initiator is the requesting party and controls the
+     * request-response initiation and termination, the target can offer
+     * key=value pairs of its own as part of a sequence and not only in
+     * response to the initiator.
+     */
+    iscsi_ds_cmd_data ds_cmd_data;
+
+    /// Optional data digest.
+    iscsi_data_digest data_digest;
 } iscsi_text_response_packet;
 
-#define ISCSI_ISID_TYPE_BITS (1 << 6) // Two bits - The T field identifies the format and usage of A, B, C, and D as
-                                      // indicated below:
-#define ISCSI_ISID_TYPE_FORMAT_OUI    0x0 // OUI-Format
-                                          // A and B: 22-bit OUI
-                                          // (the I/G and U/L bits are omitted)
-                                          // C and D: 24-bit Qualifier
-#define ISCSI_ISID_TYPE_FORMAT_EN     0x1 // EN: Format (IANA Enterprise Number)
-                                          // A: Reserved
-                                          // B and C: EN (IANA Enterprise Number)
-                                          // D: Qualifier
-#define ISCSI_ISID_TYPE_FORMAT_RANDOM 0x2 // Random
-                                          // A: Reserved
-                                          // B and C: Random
-                                          // D: Qualifier
-
-/* Only the following keys are used during the SecurityNegotiation stage
-   of the Login Phase (other keys MUST NOT be used):
-*/
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_SESSION_TYPE            "SessionType" // Use: LO, Declarative, Any-Stage
-                                                                        // Senders: Initiator
-                                                                        // Scope: SW
-                                                                        // SessionType=<Discovery|Normal>
-                                                                        // Default is Normal.
-                                                                        // The initiator indicates the type of session it wants to create. The
-                                                                        // target can either accept it or reject it.
-                                                                        // A Discovery session indicates to the target that the only purpose of
-                                                                        // this session is discovery. The only requests a target accepts in
-                                                                        // this type of session are a Text Request with a SendTargets key and a
-                                                                        // Logout Request with reason "close the session".
-                                                                        // The Discovery session implies MaxConnections = 1 and overrides both
-                                                                        // the default and an explicit setting. ErrorRecoveryLevel MUST be 0
-                                                                        // (zero) for Discovery sessions.
-                                                                        // Depending on the type of session, a target may decide on resources to
-                                                                        // allocate, the security to enforce, etc., for the session. If the
-                                                                        // SessionType key is thus going to be offered as "Discovery", it SHOULD
-                                                                        // be offered in the initial Login Request by the initiator
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_INITIATOR_NAME          "InitiatorName" // Use: IO, Declarative, Any-Stage
-                                                                          // Senders: Initiator
-                                                                          // Scope: SW
-                                                                          // InitiatorName=<iSCSI-name-value>
-                                                                          // Examples:
-                                                                          //    InitiatorName=iqn.1992-04.de.uni-freiburg.bwlehrpool:qcow2.5003
-                                                                          //    InitiatorName=iqn.2001-02.de.uni-freiburg.matrix:basty.eduroam
-                                                                          //    InitiatorName=naa.52004567BA64678D
-                                                                          // The initiator of the TCP connection MUST provide this key to the
-                                                                          // remote endpoint at the first login of the Login Phase for every
-                                                                          // connection. The InitiatorName key enables the initiator to identify
-                                                                          // itself to the remote endpoint.
-                                                                          // The InitiatorName MUST NOT be redeclared within the Login Phase
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_TARGET_NAME             "TargetName" // Use: IO by initiator, FFPO by target - only as response to a
-                                                                       // SendTargets, Declarative, Any-Stage
-                                                                       // Senders: Initiator and target
-                                                                       // Scope: SW
-                                                                       // TargetName=<iSCSI-name-value>
-                                                                       // Examples:
-                                                                       //    TargetName=iqn.1993-11.de.uni-freiburg:diskarrays.sn.5003
-                                                                       //    TargetName=eui.020000023B040506
-                                                                       //    TargetName=naa.62004567BA64678D0123456789ABCDEF
-                                                                       // The initiator of the TCP connection MUST provide this key to the
-                                                                       // remote endpoint in the first Login Request if the initiator is not
-                                                                       // establishing a Discovery session. The iSCSI Target Name specifies
-                                                                       // the worldwide unique name of the target.
-                                                                       // The TargetName key may also be returned by the SendTargets Text
-                                                                       // Request (which is its only use when issued by a target).
-                                                                       // The TargetName MUST NOT be redeclared within the Login Phase
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_TARGET_ADDRESS          "TargetAddress" // Use: ALL, Declarative, Any-Stage
-                                                                          // Senders: Target
-                                                                          // Scope: SW
-                                                                          // TargetAddress=domainname[:port][,portal-group-tag]
-                                                                          // The domainname can be specified as either a DNS host name, a dotted-
-                                                                          // decimal IPv4 address, or a bracketed IPv6 address as specified in
-                                                                          // RFC3986.
-                                                                          // If the TCP port is not specified, it is assumed to be the IANA-
-                                                                          // assigned default port for iSCSI.
-                                                                          // If the TargetAddress is returned as the result of a redirect status
-                                                                          // in a Login Response, the comma and portal-group-tag MUST be omitted.
-                                                                          // If the TargetAddress is returned within a SendTargets response, the
-                                                                          // portal-group-tag MUST be included.
-                                                                          // Examples:
-                                                                          //    TargetAddress=10.0.0.1:5003,1
-                                                                          //    TargetAddress=[1080:0:0:0:8:800:200C:417A],65
-                                                                          //    TargetAddress=[1080::8:800:200C:417A]:5003,1
-                                                                          //    TargetAddress=gitlab.uni-freiburg.de,443
-                                                                          // The formats for the port and portal-group-tag are the same as the one
-                                                                          // specified in TargetPortalGroupTag
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_INITIATOR_ALIAS         "InitiatorAlias" // Use: ALL, Declarative, Any-Stage
-                                                                           // Senders: Initiator
-                                                                           // Scope: SW
-                                                                           // InitiatorAlias=<iSCSI-local-name-value>
-                                                                           // Examples:
-                                                                           //    InitiatorAlias=Web Server 5
-                                                                           //    InitiatorAlias=matrix.uni-freiburg.de
-                                                                           //    InitiatorAlias=Matrix Server
-                                                                           // If an initiator has been configured with a human-readable name or
-                                                                           // description, it SHOULD be communicated to the target during a Login
-                                                                           // Request PDU. If not, the host name can be used instead. This string
-                                                                           // is not used as an identifier, nor is it meant to be used for
-                                                                           // authentication or authorization decisions. It can be displayed by
-                                                                           // the target's user interface in a list of initiators to which it is
-                                                                           // connected
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_TARGET_ALIAS            "TargetAlias" // Use: ALL, Declarative, Any-Stage
-                                                                        // Senders: Target
-                                                                        // Scope: SW
-                                                                        // TargetAlias=<iSCSI-local-name-value>
-                                                                        // Examples:
-                                                                        //    TargetAlias=Bob-s Disk
-                                                                        //    TargetAlias=Database Server 1 Log Disk
-                                                                        //    TargetAlias=Web Server 3 Disk 20
-                                                                        // If a target has been configured with a human-readable name or
-                                                                        // description, this name SHOULD be communicated to the initiator during
-                                                                        // a Login Response PDU if SessionType=Normal. This string is not used
-                                                                        // as an identifier, nor is it meant to be used for authentication or
-                                                                        // authorization decisions. It can be displayed by the initiator's user
-                                                                        // interface in a list of targets to which it is connected
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_TARGET_PORTAL_GROUP_TAG "TargetPortalGroupTag" // Use: IO by target, Declarative, Any-Stage
-                                                                                 // Senders: Target
-                                                                                 // Scope: SW
-                                                                                 // TargetPortalGroupTag=<16-bit-binary-value>
-                                                                                 // Example:
-                                                                                 //    TargetPortalGroupTag=1
-                                                                                 // The TargetPortalGroupTag key is a 16-bit binary-value that uniquely
-                                                                                 // identifies a portal group within an iSCSI target node. This key
-                                                                                 // carries the value of the tag of the portal group that is servicing
-                                                                                 // the Login Request. The iSCSI target returns this key to the
-                                                                                 // initiator in the Login Response PDU to the first Login Request PDU
-                                                                                 // that has the C bit set to 0 when TargetName is given by the
-                                                                                 // initiator.
-                                                                                 // SAM2 notes in its informative text that the TPGT value should be
-                                                                                 // non-zero; note that this is incorrect. A zero value is allowed as a
-                                                                                 // legal value for the TPGT. This discrepancy currently stands
-                                                                                 // corrected in SAM4
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD             "AuthMethod" // Use: During Login - Security Negotiation
-                                                                       // Senders: Initiator and target
-                                                                       // Scope: connection
-                                                                       // AuthMethod = <list-of-values>
-                                                                       // The main item of security negotiation is the authentication method
-                                                                       // (AuthMethod).
-                                                                       // The authentication methods that can be used (appear in the list-of-
-                                                                       // values) are either vendor-unique methods or those listed in the
-                                                                       // following table:
-                                                                       // +--------------------------------------------------------------+
-                                                                       // | Name         | Description                                   |
-                                                                       // +--------------------------------------------------------------+
-                                                                       // | KRB5         | Kerberos V5 - defined in RFC4120              |
-                                                                       // +--------------------------------------------------------------+
-                                                                       // | SRP          | Secure Remote Password -                      |
-                                                                       // |              | defined in RFC2945                            |
-                                                                       // +--------------------------------------------------------------+
-                                                                       // | CHAP         | Challenge Handshake Authentication Protocol - |
-                                                                       // |              | defined in RFC1994                            |
-                                                                       // +--------------------------------------------------------------+
-                                                                       // | None         | No authentication                             |
-                                                                       // +--------------------------------------------------------------+
-                                                                       // The AuthMethod selection is followed by an "authentication exchange"
-                                                                       // specific to the authentication method selected.
-                                                                       // The authentication method proposal may be made by either the
-                                                                       // initiator or the target. However, the initiator MUST make the first
-                                                                       // step specific to the selected authentication method as soon as it is
-                                                                       // selected. It follows that if the target makes the authentication
-                                                                       // method proposal, the initiator sends the first key(s) of the exchange
-                                                                       // together with its authentication method selection.
-                                                                       // The authentication exchange authenticates the initiator to the target
-                                                                       // and, optionally, the target to the initiator. Authentication is
-                                                                       // OPTIONAL to use but MUST be supported by the target and initiator.
-                                                                       // The initiator and target MUST implement CHAP. All other
-                                                                       // authentication methods are OPTIONAL.
-                                                                       // Private or public extension algorithms MAY also be negotiated for
-                                                                       // authentication methods. Whenever a private or public extension
-                                                                       // algorithm is part of the default offer (the offer made in the absence
-                                                                       // of explicit administrative action), the implementer MUST ensure that
-                                                                       // CHAP is listed as an alternative in the default offer and "None" is
-                                                                       // not part of the default offer.
-                                                                       // Extension authentication methods MUST be named using one of the
-                                                                       // following two formats:
-                                                                       //    1) Z-reversed.vendor.dns_name.do_something=
-                                                                       //    2) New public key with no name prefix constraints
-                                                                       // Authentication methods named using the Z- format are used as private
-                                                                       // extensions. New public keys must be registered with IANA using the
-                                                                       // IETF Review process RFC5226. New public extensions for
-                                                                       // authentication methods MUST NOT use the Z# name prefix.
-                                                                       // For all of the public or private extension authentication methods,
-                                                                       // the method-specific keys MUST conform to the format specified for
-                                                                       // standard-label.
-                                                                       // To identify the vendor for private extension authentication methods,
-                                                                       // we suggest using the reversed DNS-name as a prefix to the proper
-                                                                       // digest names.
-                                                                       // The part of digest-name following Z- MUST conform to the format for
-                                                                       // standard-label.
-                                                                       // Support for public or private extension authentication methods is
-                                                                       // OPTIONAL
-
-/* Kerberos V5 (KRB5) related authentication keys: */
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_KRB_AP_REQ "KRB_AP_REQ" // For KRB5 (Kerberos V5) (see RFC4120 and RFC1964), the initiator MUST use:
-                                                                      //    KRB_AP_REQ=<KRB_AP_REQ>
-                                                                      // where KRB_AP_REQ is the client message as defined in RFC4120.
-                                                                      // The default principal name assumed by an iSCSI initiator or target
-                                                                      // (prior to any administrative configuration action) MUST be the iSCSI
-                                                                      // Initiator Name or iSCSI Target Name, respectively, prefixed by the
-                                                                      // string "iscsi/".
-                                                                      // If the initiator authentication fails, the target MUST respond with a
-                                                                      // Login reject with "Authentication Failure" status. Otherwise, if the
-                                                                      // initiator has selected the mutual authentication option (by setting
-                                                                      // MUTUAL-REQUIRED in the ap-options field of the KRB_AP_REQ), the
-                                                                      // target MUST reply with:
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_KRB_AP_REP "KRB_AP_REP" //    KRB_AP_REP=<KRB_AP_REP>
-                                                                      // where KRB_AP_REP is the server's response message as defined in
-                                                                      // RFC4120.
-                                                                      // If mutual authentication was selected and target authentication
-                                                                      // fails, the initiator MUST close the connection.
-                                                                      // KRB_AP_REQ and KRB_AP_REP are binary-values, and their binary length
-                                                                      // (not the length of the character string that represents them in
-                                                                      // encoded form) MUST NOT exceed 65536 bytes. Hex or Base64 encoding
-                                                                      // may be used for KRB_AP_REQ and KRB_AP_REP
-
-/* Secure Remote Password (SRP) related authentication keys: */
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_SRP_SRP_U     "SRP_U"     // For SRP RFC2945, the initiator MUST use:
-                                                                        //    SRP_U=<U> TargetAuth=Yes or TargetAuth=No
-                                                                        // The target MUST answer with a Login reject with the "Authorization
-                                                                        // Failure" status or reply with:
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_SRP_SRP_GROUP "SRP_GROUP" //    SRP_GROUP=<G1,G2...> SRP_s=<s>
-                                                                        // where G1,G2... are proposed groups, in order of preference.
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_SRP_SRP_A     "SRP_A"     // The initiator MUST either close the connection or continue with:
-                                                                        //    SRP_A=<A>
-                                                                        //    SRP_GROUP=<G>
-                                                                        // where G is one of G1,G2... that were proposed by the target.
-                                                                        // The target MUST answer with a Login reject with the "Authentication
-                                                                        // Failure" status or reply with:
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_SRP_SRP_B     "SRP_B"     //     SRP_B=<B>
-                                                                        // The initiator MUST close the connection or continue with:
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_SRP_SRP_M     "SRP_M"     //     SRP_M=<M>
-                                                                        // If the initiator authentication fails, the target MUST answer with a
-                                                                        // Login reject with "Authentication Failure" status. Otherwise, if the
-                                                                        // initiator sent TargetAuth=Yes in the first message (requiring target
-                                                                        // authentication), the target MUST reply with:
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_SRP_SRP_HM    "SRP_HM"    //     SRP_HM=<H(A | M | K)>
-                                                                        // If the target authentication fails, the initiator MUST close the
-                                                                        // connection:
-                                                                        // where U, s, A, B, M, and H(A | M | K) are defined in RFC2945 (using
-                                                                        // the SHA1 hash function, such as SRP-SHA1) and
-                                                                        // G,Gn ("Gn" stands for G1,G2...) are identifiers of SRP groups
-                                                                        // specified in RFC3723.
-                                                                        // G, Gn, and U are text strings; s,A,B,M, and H(A | M | K) are
-                                                                        // binary-values. The length of s,A,B,M and H(A | M | K) in binary form
-                                                                        // (not the length of the character string that represents them in
-                                                                        // encoded form) MUST NOT exceed 1024 bytes. Hex or Base64 encoding may
-                                                                        // be used for s,A,B,M and H(A | M | K).
-                                                                        // For the SRP_GROUP, all the groups specified in RFC3723 up to
-                                                                        // 1536 bits (i.e. SRP-768, SRP-1024, SRP-1280, SRP-1536) must be
-                                                                        // supported by initiators and targets. To guarantee interoperability,
-                                                                        // targets MUST always offer "SRP-1536" as one of the proposed groups
-
-/* Challenge Handshake Authentication Protocol (CHAP) related authentication keys: */
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_CHAP_CHAP_A "CHAP_A" // For CHAP RFC1994, the initiator MUST use:
-                                                                   //    CHAP_A=<A1,A2...>
-                                                                   // where A1,A2... are proposed algorithms, in order of preference.
-                                                                   // The target MUST answer with a Login reject with the "Authentication
-                                                                   // Failure" status or reply with:
-                                                                   //    CHAP_A=<A>
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_CHAP_CHAP_I "CHAP_I" //    CHAP_I=<I>
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_CHAP_CHAP_C "CHAP_C" //    CHAP_C=<C>
-                                                                   // where A is one of A1,A2... that were proposed by the initiator.
-                                                                   // The initiator MUST continue with:
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_CHAP_CHAP_N "CHAP_N" //    CHAP_N=<N>
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_AUTH_METHOD_CHAP_CHAP_R "CHAP_R" //    CHAP_R=<R>
-                                                                   // or, if it requires target authentication, with:
-                                                                   //    CHAP_N=<N>
-                                                                   //    CHAP_R=<R>
-                                                                   //    CHAP_I=<I>
-                                                                   //    CHAP_C=<C>
-                                                                   // If the initiator authentication fails, the target MUST answer with a
-                                                                   // Login reject with "Authentication Failure" status. Otherwise, if the
-                                                                   // initiator required target authentication, the target MUST either
-                                                                   // answer with a Login reject with "Authentication Failure" or reply
-                                                                   // with:
-                                                                   //    CHAP_N=<N>
-                                                                   //    CHAP_R=<R>
-                                                                   // If the target authentication fails, the initiator MUST close the
-                                                                   // connection:
-                                                                   // where N, (A,A1,A2), I, C, and R are (correspondingly) the Name,
-                                                                   // Algorithm, Identifier, Challenge, and Response as defined in
-                                                                   // RFC1994.
-                                                                   // N is a text string; A,A1,A2, and I are numbers; C and R are
-                                                                   // binary-values. Their binary length (not the length of the character
-                                                                   // string that represents them in encoded form) MUST NOT exceed
-                                                                   // 1024 bytes. Hex or Base64 encoding may be used for C and R.
-                                                                   // For the Algorithm, as stated in [RFC1994], one value is required to
-                                                                   // be implemented:
-                                                                   // 5     (CHAP with MD5)
-                                                                   // To guarantee interoperability, initiators MUST always offer it as one
-                                                                   // of the proposed algorithms
+/// Initiator Session ID (ISID) type: Two bits - The T field identifies the format and usage of A, B, C, and D.
+#define ISCSI_ISID_TYPE_BITS (1 << 6)
+
+/**
+ * @brief Initiator Session ID (ISID) type: OUI-Format.
+ *
+ * A and B: 22-bit OUI
+ * (the I/G and U/L bits are omitted)
+ * C and D: 24-bit Qualifier.
+ */
+#define ISCSI_ISID_TYPE_FORMAT_OUI    0x0
+
+/**
+ * @brief Initiator Session ID (ISID) type: EN: Format (IANA Enterprise Number).
+ *
+ * A: Reserved
+ * B and C: EN (IANA Enterprise Number)
+ * D: Qualifier
+ */
+#define ISCSI_ISID_TYPE_FORMAT_EN     0x1
+
+/**
+ * @brief Initiator Session ID (ISID) type: Random.
+ *
+ * A: Reserved
+ * B and C: Random
+ * D: Qualifier
+ */
+#define ISCSI_ISID_TYPE_FORMAT_RANDOM 0x2
+
+/**
+ * @brief iSCSI Initiator Session ID (ISID) packet data.
+ *
+ * This is an initiator-defined component of the session identifier and
+ * is structured as follows:
+ *
+ * For the T field values 00b and 01b, a combination of A and B (for
+ * 00b) or B and C (for 01b) identifies the vendor or organization whose
+ * component (software or hardware) generates this ISID. A vendor or
+ * organization with one or more OUIs, or one or more Enterprise
+ * Numbers, MUST use at least one of these numbers and select the
+ * appropriate value for the T field when its components generate ISIDs.
+ * An OUI or EN MUST be set in the corresponding fields in network byte
+ * order (byte big-endian).
+ *
+ * If the T field is 10b, B and C are set to a random 24-bit unsigned
+ * integer value in network byte order (byte big-endian).
+ *
+ * The Qualifier field is a 16-bit or 24-bit unsigned integer value that
+ * provides a range of possible values for the ISID within the selected
+ * namespace. It may be set to any value within the constraints
+ * specified in the iSCSI protocol.
+ *
+ * If the ISID is derived from something assigned to a hardware adapter
+ * or interface by a vendor as a preset default value, it MUST be
+ * configurable to a value assigned according to the SCSI port behavior
+ * desired by the system in which it is installed. The resultant ISID
+ * MUST also be persistent over power cycles, reboot, card swap, etc.
+ */
+typedef struct __attribute__((packed)) iscsi_isid {
+    /// Meaning depends on T bit, either 22-bit OUI or reserved.
+    uint8_t a;
+
+    /// Meaning depends on T bit, either 22-bit OUI, EN (IANA Enterprise Number) or random.
+    uint16_t b;
+
+    /// Meaning depends on T bit, either 24-bit Qualifier, EN (IANA Enterprise Number) or random.
+    uint8_t c;
+
+    /// Meaning depends on T bit, either 24-bit Qualifier or Qualifier.
+    uint16_t d;
+} iscsi_isid;
+
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Session type.
+ *
+ * @verbatim
+ * Use: LO, Declarative, Any-Stage
+ * Senders: Initiator
+ * Scope: SW
+ * SessionType=<Discovery|Normal>
+ * Default is Normal.
+ * @endverbatim
+ * The initiator indicates the type of session it wants to create. The
+ * target can either accept it or reject it.\n
+ * A Discovery session indicates to the target that the only purpose of
+ * this session is discovery. The only requests a target accepts in
+ * this type of session are a Text Request with a SendTargets key and a
+ * Logout Request with reason "close the session".\n
+ * The Discovery session implies MaxConnections = 1 and overrides both
+ * the default and an explicit setting. ErrorRecoveryLevel MUST be 0
+ * (zero) for Discovery sessions.\n
+ * Depending on the type of session, a target may decide on resources to
+ * allocate, the security to enforce, etc., for the session. If the
+ * SessionType key is thus going to be offered as "Discovery", it SHOULD
+ * be offered in the initial Login Request by the initiator.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_SESSION_TYPE            "SessionType"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Initiator name.
+ *
+ * @verbatim
+ * Use: IO, Declarative, Any-Stage
+ * Senders: Initiator
+ * Scope: SW
+ * InitiatorName=<iSCSI-name-value>
+ * Examples:
+ *    InitiatorName=iqn.1992-04.de.uni-freiburg.bwlehrpool:qcow2.5003
+ *    InitiatorName=iqn.2001-02.de.uni-freiburg.matrix:basty.eduroam
+ *    InitiatorName=naa.52004567BA64678D
+ * @endverbatim
+ * The initiator of the TCP connection MUST provide this key to the
+ * remote endpoint at the first login of the Login Phase for every
+ * connection. The InitiatorName key enables the initiator to identify
+ * itself to the remote endpoint.\n
+ * The InitiatorName MUST NOT be redeclared within the Login Phase.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_INITIATOR_NAME          "InitiatorName"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Target name.
+ *
+ * @verbatim
+ * Use: IO by initiator, FFPO by target - only as response to a
+ * SendTargets, Declarative, Any-Stage
+ * Senders: Initiator and target
+ * Scope: SW
+ * TargetName=<iSCSI-name-value>
+ * Examples:
+ *    TargetName=iqn.1993-11.de.uni-freiburg:diskarrays.sn.5003
+ *    TargetName=eui.020000023B040506
+ *    TargetName=naa.62004567BA64678D0123456789ABCDEF
+ * @endverbatim
+ * The initiator of the TCP connection MUST provide this key to the
+ * remote endpoint in the first Login Request if the initiator is not
+ * establishing a Discovery session. The iSCSI Target Name specifies
+ * the worldwide unique name of the target.\n
+ * The TargetName key may also be returned by the SendTargets Text
+ * Request (which is its only use when issued by a target).\n
+ * The TargetName MUST NOT be redeclared within the Login Phase.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_TARGET_NAME             "TargetName"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Target address.
+ *
+ * @verbatim
+ * Use: ALL, Declarative, Any-Stage
+ * Senders: Target
+ * Scope: SW
+ * TargetAddress=domainname[:port][,portal-group-tag]
+ * @endverbatim
+ * The domainname can be specified as either a DNS host name, a dotted-
+ * decimal IPv4 address, or a bracketed IPv6 address as specified in
+ * RFC3986.\n
+ * If the TCP port is not specified, it is assumed to be the IANA-
+ * assigned default port for iSCSI.\n
+ * If the TargetAddress is returned as the result of a redirect status
+ * in a Login Response, the comma and portal-group-tag MUST be omitted.
+ * If the TargetAddress is returned within a SendTargets response, the
+ * portal-group-tag MUST be included.\n
+ * @verbatim
+ * Examples:
+ *    TargetAddress=10.0.0.1:5003,1
+ *    TargetAddress=[1080:0:0:0:8:800:200C:417A],65
+ *    TargetAddress=[1080::8:800:200C:417A]:5003,1
+ *    TargetAddress=gitlab.uni-freiburg.de,443
+ * @endverbatim
+ * The formats for the port and portal-group-tag are the same as the one
+ * specified in TargetPortalGroupTag.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_TARGET_ADDRESS          "TargetAddress"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Initiator alias.
+ *
+ * @verbatim
+ * Use: ALL, Declarative, Any-Stage
+ * Senders: Initiator
+ * Scope: SW
+ * InitiatorAlias=<iSCSI-local-name-value>
+ * Examples:
+ *    InitiatorAlias=Web Server 5
+ *    InitiatorAlias=matrix.uni-freiburg.de
+ *    InitiatorAlias=Matrix Server
+ * @endverbatim
+ * If an initiator has been configured with a human-readable name or
+ * description, it SHOULD be communicated to the target during a Login
+ * Request PDU. If not, the host name can be used instead. This string
+ * is not used as an identifier, nor is it meant to be used for
+ * authentication or authorization decisions. It can be displayed by
+ * the target's user interface in a list of initiators to which it is
+ * connected.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_INITIATOR_ALIAS         "InitiatorAlias"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Target alias.
+ *
+ * @verbatim
+ * Use: ALL, Declarative, Any-Stage
+ * Senders: Target
+ * Scope: SW
+ * TargetAlias=<iSCSI-local-name-value>
+ * Examples:
+ *    TargetAlias=Bob-s Disk
+ *    TargetAlias=Database Server 1 Log Disk
+ *    TargetAlias=Web Server 3 Disk 20
+ * @endverbatim
+ * If a target has been configured with a human-readable name or
+ * description, this name SHOULD be communicated to the initiator during
+ * a Login Response PDU if SessionType=Normal. This string is not used
+ * as an identifier, nor is it meant to be used for authentication or
+ * authorization decisions. It can be displayed by the initiator's user
+ * interface in a list of targets to which it is connected.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_TARGET_ALIAS            "TargetAlias"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Target portal group tag.
+ *
+ * @verbatim
+ * Use: IO by target, Declarative, Any-Stage
+ * Senders: Target
+ * Scope: SW
+ * TargetPortalGroupTag=<16-bit-binary-value>
+ * Example:
+ *    TargetPortalGroupTag=1
+ * @endverbatim
+ * The TargetPortalGroupTag key is a 16-bit binary-value that uniquely
+ * identifies a portal group within an iSCSI target node. This key
+ * carries the value of the tag of the portal group that is servicing
+ * the Login Request. The iSCSI target returns this key to the
+ * initiator in the Login Response PDU to the first Login Request PDU
+ * that has the C bit set to 0 when TargetName is given by the
+ * initiator.\n
+ * SAM2 notes in its informative text that the TPGT value should be
+ * non-zero; note that this is incorrect. A zero value is allowed as a
+ * legal value for the TPGT. This discrepancy currently stands
+ * corrected in SAM4.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_TARGET_PORTAL_GROUP_TAG "TargetPortalGroupTag"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Authentication method.
+ *
+ * @verbatim
+ * Use: During Login - Security Negotiation
+ * Senders: Initiator and target
+ * Scope: connection
+ * AuthMethod = <list-of-values>
+ * @endverbatim
+ * The main item of security negotiation is the authentication method
+ * (AuthMethod).\n
+ * The authentication methods that can be used (appear in the list-of-
+ * values) are either vendor-unique methods or those listed in the
+ * following table:
+ * Name | Description
+ * :--- | :---------------------------------------------------------------
+ * KRB5 | Kerberos V5 - defined in RFC4120
+ * SRP  | Secure Remote Password - defined in RFC2945
+ * CHAP | Challenge Handshake Authentication Protocol - defined in RFC1994
+ * None | No authentication
+ *
+ * The AuthMethod selection is followed by an "authentication exchange"
+ * specific to the authentication method selected.\n
+ * The authentication method proposal may be made by either the
+ * initiator or the target. However, the initiator MUST make the first
+ * step specific to the selected authentication method as soon as it is
+ * selected. It follows that if the target makes the authentication
+ * method proposal, the initiator sends the first key(s) of the exchange
+ * together with its authentication method selection.\n
+ * The authentication exchange authenticates the initiator to the target
+ * and, optionally, the target to the initiator. Authentication is
+ * OPTIONAL to use but MUST be supported by the target and initiator.
+ * The initiator and target MUST implement CHAP. All other
+ * authentication methods are OPTIONAL.\n
+ * Private or public extension algorithms MAY also be negotiated for
+ * authentication methods. Whenever a private or public extension
+ * algorithm is part of the default offer (the offer made in the absence
+ * of explicit administrative action), the implementer MUST ensure that
+ * CHAP is listed as an alternative in the default offer and "None" is
+ * not part of the default offer.\n
+ * Extension authentication methods MUST be named using one of the
+ * following two formats:
+ *    -# Z-reversed.vendor.dns_name.do_something=
+ *    -# New public key with no name prefix constraints
+ *
+ * Authentication methods named using the Z- format are used as private
+ * extensions. New public keys must be registered with IANA using the
+ * IETF Review process RFC5226. New public extensions for
+ * authentication methods MUST NOT use the Z# name prefix.\n
+ * For all of the public or private extension authentication methods,
+ * the method-specific keys MUST conform to the format specified for
+ * standard-label.\n
+ * To identify the vendor for private extension authentication methods,
+ * we suggest using the reversed DNS-name as a prefix to the proper
+ * digest names.\n
+ * The part of digest-name following Z- MUST conform to the format for
+ * standard-label.\n
+ * Support for public or private extension authentication methods is
+ * OPTIONAL.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD             "AuthMethod"
+
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Kerberos V5 (KRB5): KRB_AP_REQ.
+ *
+ * For KRB5 (Kerberos V5) (see RFC4120 and RFC1964), the initiator MUST use:
+ * @verbatim
+ *    KRB_AP_REQ=<KRB_AP_REQ>
+ * @endverbatim
+ * where KRB_AP_REQ is the client message as defined in RFC4120.
+ * The default principal name assumed by an iSCSI initiator or target
+ * (prior to any administrative configuration action) MUST be the iSCSI
+ * Initiator Name or iSCSI Target Name, respectively, prefixed by the
+ * string "iscsi/".\n
+ * If the initiator authentication fails, the target MUST respond with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator has selected the mutual authentication option (by setting
+ * MUTUAL-REQUIRED in the ap-options field of the KRB_AP_REQ), the
+ * target MUST reply with:
+ * @verbatim
+ *    KRB_AP_REP=<KRB_AP_REP>
+ * @endverbatim
+ * where KRB_AP_REP is the server's response message as defined in
+ * RFC4120.\n
+ * If mutual authentication was selected and target authentication
+ * fails, the initiator MUST close the connection.\n
+ * KRB_AP_REQ and KRB_AP_REP are binary-values, and their binary length
+ * (not the length of the character string that represents them in
+ * encoded form) MUST NOT exceed 65536 bytes. Hex or Base64 encoding
+ * may be used for KRB_AP_REQ and KRB_AP_REP.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_KRB_AP_REQ "KRB_AP_REQ"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Kerberos V5 (KRB5): KRB_AP_REP.
+ *
+ * For KRB5 (Kerberos V5) (see RFC4120 and RFC1964), the initiator MUST use:
+ * @verbatim
+ *    KRB_AP_REQ=<KRB_AP_REQ>
+ * @endverbatim
+ * where KRB_AP_REQ is the client message as defined in RFC4120.
+ * The default principal name assumed by an iSCSI initiator or target
+ * (prior to any administrative configuration action) MUST be the iSCSI
+ * Initiator Name or iSCSI Target Name, respectively, prefixed by the
+ * string "iscsi/".\n
+ * If the initiator authentication fails, the target MUST respond with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator has selected the mutual authentication option (by setting
+ * MUTUAL-REQUIRED in the ap-options field of the KRB_AP_REQ), the
+ * target MUST reply with:
+ * @verbatim
+ *    KRB_AP_REP=<KRB_AP_REP>
+ * @endverbatim
+ * where KRB_AP_REP is the server's response message as defined in
+ * RFC4120.\n
+ * If mutual authentication was selected and target authentication
+ * fails, the initiator MUST close the connection.\n
+ * KRB_AP_REQ and KRB_AP_REP are binary-values, and their binary length
+ * (not the length of the character string that represents them in
+ * encoded form) MUST NOT exceed 65536 bytes. Hex or Base64 encoding
+ * may be used for KRB_AP_REQ and KRB_AP_REP.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_KRB_AP_REP "KRB_AP_REP"
+
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Secure Remote Password (SRP): SRP_U.
+ *
+ * For SRP RFC2945, the initiator MUST use:
+ * @verbatim
+ *    SRP_U=<U> TargetAuth=Yes or TargetAuth=No
+ * @endverbatim
+ * The target MUST answer with a Login reject with the "Authorization
+ * Failure" status or reply with:
+ * @verbatim
+ *    SRP_GROUP=<G1,G2...> SRP_s=<s>
+ * @endverbatim
+ * where G1,G2... are proposed groups, in order of preference.
+ * The initiator MUST either close the connection or continue with:
+ * @verbatim
+ *    SRP_A=<A>
+ *    SRP_GROUP=<G>
+ * @endverbatim
+ * where G is one of G1,G2... that were proposed by the target.
+ * The target MUST answer with a Login reject with the "Authentication
+ * Failure" status or reply with:
+ * @verbatim
+ *     SRP_B=<B>
+ * @endverbatim
+ * The initiator MUST close the connection or continue with:
+ * @verbatim
+ *     SRP_M=<M>
+ * @endverbatim
+ * If the initiator authentication fails, the target MUST answer with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator sent TargetAuth=Yes in the first message (requiring target
+ * authentication), the target MUST reply with:
+ * @verbatim
+ *     SRP_HM=<H(A | M | K)>
+ * @endverbatim
+ * If the target authentication fails, the initiator MUST close the
+ * connection:\n
+ * where U, s, A, B, M, and H(A | M | K) are defined in RFC2945 (using
+ * the SHA1 hash function, such as SRP-SHA1) and
+ * G,Gn ("Gn" stands for G1,G2...) are identifiers of SRP groups
+ * specified in RFC3723.\n
+ * G, Gn, and U are text strings; s,A,B,M, and H(A | M | K) are
+ * binary-values. The length of s,A,B,M and H(A | M | K) in binary form
+ * (not the length of the character string that represents them in
+ * encoded form) MUST NOT exceed 1024 bytes. Hex or Base64 encoding may
+ * be used for s,A,B,M and H(A | M | K).\n
+ * For the SRP_GROUP, all the groups specified in RFC3723 up to
+ * 1536 bits (i.e. SRP-768, SRP-1024, SRP-1280, SRP-1536) must be
+ * supported by initiators and targets. To guarantee interoperability,
+ * targets MUST always offer "SRP-1536" as one of the proposed groups.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_SRP_SRP_U     "SRP_U"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Secure Remote Password (SRP): SRP_GROUP.
+ *
+ * For SRP RFC2945, the initiator MUST use:
+ * @verbatim
+ *    SRP_U=<U> TargetAuth=Yes or TargetAuth=No
+ * @endverbatim
+ * The target MUST answer with a Login reject with the "Authorization
+ * Failure" status or reply with:
+ * @verbatim
+ *    SRP_GROUP=<G1,G2...> SRP_s=<s>
+ * @endverbatim
+ * where G1,G2... are proposed groups, in order of preference.
+ * The initiator MUST either close the connection or continue with:
+ * @verbatim
+ *    SRP_A=<A>
+ *    SRP_GROUP=<G>
+ * @endverbatim
+ * where G is one of G1,G2... that were proposed by the target.
+ * The target MUST answer with a Login reject with the "Authentication
+ * Failure" status or reply with:
+ * @verbatim
+ *     SRP_B=<B>
+ * @endverbatim
+ * The initiator MUST close the connection or continue with:
+ * @verbatim
+ *     SRP_M=<M>
+ * @endverbatim
+ * If the initiator authentication fails, the target MUST answer with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator sent TargetAuth=Yes in the first message (requiring target
+ * authentication), the target MUST reply with:
+ * @verbatim
+ *     SRP_HM=<H(A | M | K)>
+ * @endverbatim
+ * If the target authentication fails, the initiator MUST close the
+ * connection:\n
+ * where U, s, A, B, M, and H(A | M | K) are defined in RFC2945 (using
+ * the SHA1 hash function, such as SRP-SHA1) and
+ * G,Gn ("Gn" stands for G1,G2...) are identifiers of SRP groups
+ * specified in RFC3723.\n
+ * G, Gn, and U are text strings; s,A,B,M, and H(A | M | K) are
+ * binary-values. The length of s,A,B,M and H(A | M | K) in binary form
+ * (not the length of the character string that represents them in
+ * encoded form) MUST NOT exceed 1024 bytes. Hex or Base64 encoding may
+ * be used for s,A,B,M and H(A | M | K).\n
+ * For the SRP_GROUP, all the groups specified in RFC3723 up to
+ * 1536 bits (i.e. SRP-768, SRP-1024, SRP-1280, SRP-1536) must be
+ * supported by initiators and targets. To guarantee interoperability,
+ * targets MUST always offer "SRP-1536" as one of the proposed groups.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_SRP_SRP_GROUP "SRP_GROUP"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Secure Remote Password (SRP): SRP_A.
+ *
+ * For SRP RFC2945, the initiator MUST use:
+ * @verbatim
+ *    SRP_U=<U> TargetAuth=Yes or TargetAuth=No
+ * @endverbatim
+ * The target MUST answer with a Login reject with the "Authorization
+ * Failure" status or reply with:
+ * @verbatim
+ *    SRP_GROUP=<G1,G2...> SRP_s=<s>
+ * @endverbatim
+ * where G1,G2... are proposed groups, in order of preference.
+ * The initiator MUST either close the connection or continue with:
+ * @verbatim
+ *    SRP_A=<A>
+ *    SRP_GROUP=<G>
+ * @endverbatim
+ * where G is one of G1,G2... that were proposed by the target.
+ * The target MUST answer with a Login reject with the "Authentication
+ * Failure" status or reply with:
+ * @verbatim
+ *     SRP_B=<B>
+ * @endverbatim
+ * The initiator MUST close the connection or continue with:
+ * @verbatim
+ *     SRP_M=<M>
+ * @endverbatim
+ * If the initiator authentication fails, the target MUST answer with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator sent TargetAuth=Yes in the first message (requiring target
+ * authentication), the target MUST reply with:
+ * @verbatim
+ *     SRP_HM=<H(A | M | K)>
+ * @endverbatim
+ * If the target authentication fails, the initiator MUST close the
+ * connection:\n
+ * where U, s, A, B, M, and H(A | M | K) are defined in RFC2945 (using
+ * the SHA1 hash function, such as SRP-SHA1) and
+ * G,Gn ("Gn" stands for G1,G2...) are identifiers of SRP groups
+ * specified in RFC3723.\n
+ * G, Gn, and U are text strings; s,A,B,M, and H(A | M | K) are
+ * binary-values. The length of s,A,B,M and H(A | M | K) in binary form
+ * (not the length of the character string that represents them in
+ * encoded form) MUST NOT exceed 1024 bytes. Hex or Base64 encoding may
+ * be used for s,A,B,M and H(A | M | K).\n
+ * For the SRP_GROUP, all the groups specified in RFC3723 up to
+ * 1536 bits (i.e. SRP-768, SRP-1024, SRP-1280, SRP-1536) must be
+ * supported by initiators and targets. To guarantee interoperability,
+ * targets MUST always offer "SRP-1536" as one of the proposed groups.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_SRP_SRP_A     "SRP_A"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Secure Remote Password (SRP): SRP_B.
+ *
+ * For SRP RFC2945, the initiator MUST use:
+ * @verbatim
+ *    SRP_U=<U> TargetAuth=Yes or TargetAuth=No
+ * @endverbatim
+ * The target MUST answer with a Login reject with the "Authorization
+ * Failure" status or reply with:
+ * @verbatim
+ *    SRP_GROUP=<G1,G2...> SRP_s=<s>
+ * @endverbatim
+ * where G1,G2... are proposed groups, in order of preference.
+ * The initiator MUST either close the connection or continue with:
+ * @verbatim
+ *    SRP_A=<A>
+ *    SRP_GROUP=<G>
+ * @endverbatim
+ * where G is one of G1,G2... that were proposed by the target.
+ * The target MUST answer with a Login reject with the "Authentication
+ * Failure" status or reply with:
+ * @verbatim
+ *     SRP_B=<B>
+ * @endverbatim
+ * The initiator MUST close the connection or continue with:
+ * @verbatim
+ *     SRP_M=<M>
+ * @endverbatim
+ * If the initiator authentication fails, the target MUST answer with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator sent TargetAuth=Yes in the first message (requiring target
+ * authentication), the target MUST reply with:
+ * @verbatim
+ *     SRP_HM=<H(A | M | K)>
+ * @endverbatim
+ * If the target authentication fails, the initiator MUST close the
+ * connection:\n
+ * where U, s, A, B, M, and H(A | M | K) are defined in RFC2945 (using
+ * the SHA1 hash function, such as SRP-SHA1) and
+ * G,Gn ("Gn" stands for G1,G2...) are identifiers of SRP groups
+ * specified in RFC3723.\n
+ * G, Gn, and U are text strings; s,A,B,M, and H(A | M | K) are
+ * binary-values. The length of s,A,B,M and H(A | M | K) in binary form
+ * (not the length of the character string that represents them in
+ * encoded form) MUST NOT exceed 1024 bytes. Hex or Base64 encoding may
+ * be used for s,A,B,M and H(A | M | K).\n
+ * For the SRP_GROUP, all the groups specified in RFC3723 up to
+ * 1536 bits (i.e. SRP-768, SRP-1024, SRP-1280, SRP-1536) must be
+ * supported by initiators and targets. To guarantee interoperability,
+ * targets MUST always offer "SRP-1536" as one of the proposed groups.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_SRP_SRP_B     "SRP_B"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Secure Remote Password (SRP): SRP_M.
+ *
+ * For SRP RFC2945, the initiator MUST use:
+ * @verbatim
+ *    SRP_U=<U> TargetAuth=Yes or TargetAuth=No
+ * @endverbatim
+ * The target MUST answer with a Login reject with the "Authorization
+ * Failure" status or reply with:
+ * @verbatim
+ *    SRP_GROUP=<G1,G2...> SRP_s=<s>
+ * @endverbatim
+ * where G1,G2... are proposed groups, in order of preference.
+ * The initiator MUST either close the connection or continue with:
+ * @verbatim
+ *    SRP_A=<A>
+ *    SRP_GROUP=<G>
+ * @endverbatim
+ * where G is one of G1,G2... that were proposed by the target.
+ * The target MUST answer with a Login reject with the "Authentication
+ * Failure" status or reply with:
+ * @verbatim
+ *     SRP_B=<B>
+ * @endverbatim
+ * The initiator MUST close the connection or continue with:
+ * @verbatim
+ *     SRP_M=<M>
+ * @endverbatim
+ * If the initiator authentication fails, the target MUST answer with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator sent TargetAuth=Yes in the first message (requiring target
+ * authentication), the target MUST reply with:
+ * @verbatim
+ *     SRP_HM=<H(A | M | K)>
+ * @endverbatim
+ * If the target authentication fails, the initiator MUST close the
+ * connection:\n
+ * where U, s, A, B, M, and H(A | M | K) are defined in RFC2945 (using
+ * the SHA1 hash function, such as SRP-SHA1) and
+ * G,Gn ("Gn" stands for G1,G2...) are identifiers of SRP groups
+ * specified in RFC3723.\n
+ * G, Gn, and U are text strings; s,A,B,M, and H(A | M | K) are
+ * binary-values. The length of s,A,B,M and H(A | M | K) in binary form
+ * (not the length of the character string that represents them in
+ * encoded form) MUST NOT exceed 1024 bytes. Hex or Base64 encoding may
+ * be used for s,A,B,M and H(A | M | K).\n
+ * For the SRP_GROUP, all the groups specified in RFC3723 up to
+ * 1536 bits (i.e. SRP-768, SRP-1024, SRP-1280, SRP-1536) must be
+ * supported by initiators and targets. To guarantee interoperability,
+ * targets MUST always offer "SRP-1536" as one of the proposed groups.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_SRP_SRP_M     "SRP_M"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Secure Remote Password (SRP): SRP_HM.
+ *
+ * For SRP RFC2945, the initiator MUST use:
+ * @verbatim
+ *    SRP_U=<U> TargetAuth=Yes or TargetAuth=No
+ * @endverbatim
+ * The target MUST answer with a Login reject with the "Authorization
+ * Failure" status or reply with:
+ * @verbatim
+ *    SRP_GROUP=<G1,G2...> SRP_s=<s>
+ * @endverbatim
+ * where G1,G2... are proposed groups, in order of preference.
+ * The initiator MUST either close the connection or continue with:
+ * @verbatim
+ *    SRP_A=<A>
+ *    SRP_GROUP=<G>
+ * @endverbatim
+ * where G is one of G1,G2... that were proposed by the target.
+ * The target MUST answer with a Login reject with the "Authentication
+ * Failure" status or reply with:
+ * @verbatim
+ *     SRP_B=<B>
+ * @endverbatim
+ * The initiator MUST close the connection or continue with:
+ * @verbatim
+ *     SRP_M=<M>
+ * @endverbatim
+ * If the initiator authentication fails, the target MUST answer with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator sent TargetAuth=Yes in the first message (requiring target
+ * authentication), the target MUST reply with:
+ * @verbatim
+ *     SRP_HM=<H(A | M | K)>
+ * @endverbatim
+ * If the target authentication fails, the initiator MUST close the
+ * connection:\n
+ * where U, s, A, B, M, and H(A | M | K) are defined in RFC2945 (using
+ * the SHA1 hash function, such as SRP-SHA1) and
+ * G,Gn ("Gn" stands for G1,G2...) are identifiers of SRP groups
+ * specified in RFC3723.\n
+ * G, Gn, and U are text strings; s,A,B,M, and H(A | M | K) are
+ * binary-values. The length of s,A,B,M and H(A | M | K) in binary form
+ * (not the length of the character string that represents them in
+ * encoded form) MUST NOT exceed 1024 bytes. Hex or Base64 encoding may
+ * be used for s,A,B,M and H(A | M | K).\n
+ * For the SRP_GROUP, all the groups specified in RFC3723 up to
+ * 1536 bits (i.e. SRP-768, SRP-1024, SRP-1280, SRP-1536) must be
+ * supported by initiators and targets. To guarantee interoperability,
+ * targets MUST always offer "SRP-1536" as one of the proposed groups.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_SRP_SRP_HM    "SRP_HM"
+
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Challenge Handshake Authentication Protocol (CHAP): CHAP_A.
+ *
+ * For CHAP RFC1994, the initiator MUST use:
+ * @verbatim
+ *    CHAP_A=<A1,A2...>
+ * @endverbatim
+ * where A1,A2... are proposed algorithms, in order of preference.
+ * The target MUST answer with a Login reject with the "Authentication
+ * Failure" status or reply with:
+ * @verbatim
+ *    CHAP_A=<A>
+ *    CHAP_I=<I>
+ *    CHAP_C=<C>
+ * @endverbatim
+ * where A is one of A1,A2... that were proposed by the initiator.
+ * The initiator MUST continue with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ * @endverbatim
+ * or, if it requires target authentication, with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ *    CHAP_I=<I>
+ *    CHAP_C=<C>
+ * @endverbatim
+ * If the initiator authentication fails, the target MUST answer with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator required target authentication, the target MUST either
+ * answer with a Login reject with "Authentication Failure" or reply
+ * with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ * @endverbatim
+ * If the target authentication fails, the initiator MUST close the
+ * connection:\n
+ * where N, (A,A1,A2), I, C, and R are (correspondingly) the Name,
+ * Algorithm, Identifier, Challenge, and Response as defined in
+ * RFC1994.\n
+ * N is a text string; A,A1,A2, and I are numbers; C and R are
+ * binary-values. Their binary length (not the length of the character
+ * string that represents them in encoded form) MUST NOT exceed
+ * 1024 bytes. Hex or Base64 encoding may be used for C and R.\n
+ * For the Algorithm, as stated in [RFC1994], one value is required to
+ * be implemented:
+ * @verbatim
+ *    5     (CHAP with MD5)
+ * @endverbatim
+ * To guarantee interoperability, initiators MUST always offer it as one
+ * of the proposed algorithms.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_CHAP_CHAP_A "CHAP_A"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Challenge Handshake Authentication Protocol (CHAP): CHAP_I.
+ *
+ * For CHAP RFC1994, the initiator MUST use:
+ * @verbatim
+ *    CHAP_A=<A1,A2...>
+ * @endverbatim
+ * where A1,A2... are proposed algorithms, in order of preference.
+ * The target MUST answer with a Login reject with the "Authentication
+ * Failure" status or reply with:
+ * @verbatim
+ *    CHAP_A=<A>
+ *    CHAP_I=<I>
+ *    CHAP_C=<C>
+ * @endverbatim
+ * where A is one of A1,A2... that were proposed by the initiator.
+ * The initiator MUST continue with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ * @endverbatim
+ * or, if it requires target authentication, with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ *    CHAP_I=<I>
+ *    CHAP_C=<C>
+ * @endverbatim
+ * If the initiator authentication fails, the target MUST answer with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator required target authentication, the target MUST either
+ * answer with a Login reject with "Authentication Failure" or reply
+ * with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ * @endverbatim
+ * If the target authentication fails, the initiator MUST close the
+ * connection:\n
+ * where N, (A,A1,A2), I, C, and R are (correspondingly) the Name,
+ * Algorithm, Identifier, Challenge, and Response as defined in
+ * RFC1994.\n
+ * N is a text string; A,A1,A2, and I are numbers; C and R are
+ * binary-values. Their binary length (not the length of the character
+ * string that represents them in encoded form) MUST NOT exceed
+ * 1024 bytes. Hex or Base64 encoding may be used for C and R.\n
+ * For the Algorithm, as stated in [RFC1994], one value is required to
+ * be implemented:
+ * @verbatim
+ *    5     (CHAP with MD5)
+ * @endverbatim
+ * To guarantee interoperability, initiators MUST always offer it as one
+ * of the proposed algorithms.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_CHAP_CHAP_I "CHAP_I"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Challenge Handshake Authentication Protocol (CHAP): CHAP_C.
+ *
+ * For CHAP RFC1994, the initiator MUST use:
+ * @verbatim
+ *    CHAP_A=<A1,A2...>
+ * @endverbatim
+ * where A1,A2... are proposed algorithms, in order of preference.
+ * The target MUST answer with a Login reject with the "Authentication
+ * Failure" status or reply with:
+ * @verbatim
+ *    CHAP_A=<A>
+ *    CHAP_I=<I>
+ *    CHAP_C=<C>
+ * @endverbatim
+ * where A is one of A1,A2... that were proposed by the initiator.
+ * The initiator MUST continue with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ * @endverbatim
+ * or, if it requires target authentication, with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ *    CHAP_I=<I>
+ *    CHAP_C=<C>
+ * @endverbatim
+ * If the initiator authentication fails, the target MUST answer with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator required target authentication, the target MUST either
+ * answer with a Login reject with "Authentication Failure" or reply
+ * with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ * @endverbatim
+ * If the target authentication fails, the initiator MUST close the
+ * connection:\n
+ * where N, (A,A1,A2), I, C, and R are (correspondingly) the Name,
+ * Algorithm, Identifier, Challenge, and Response as defined in
+ * RFC1994.\n
+ * N is a text string; A,A1,A2, and I are numbers; C and R are
+ * binary-values. Their binary length (not the length of the character
+ * string that represents them in encoded form) MUST NOT exceed
+ * 1024 bytes. Hex or Base64 encoding may be used for C and R.\n
+ * For the Algorithm, as stated in [RFC1994], one value is required to
+ * be implemented:
+ * @verbatim
+ *    5     (CHAP with MD5)
+ * @endverbatim
+ * To guarantee interoperability, initiators MUST always offer it as one
+ * of the proposed algorithms.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_CHAP_CHAP_C "CHAP_C"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Challenge Handshake Authentication Protocol (CHAP): CHAP_N.
+ *
+ * For CHAP RFC1994, the initiator MUST use:
+ * @verbatim
+ *    CHAP_A=<A1,A2...>
+ * @endverbatim
+ * where A1,A2... are proposed algorithms, in order of preference.
+ * The target MUST answer with a Login reject with the "Authentication
+ * Failure" status or reply with:
+ * @verbatim
+ *    CHAP_A=<A>
+ *    CHAP_I=<I>
+ *    CHAP_C=<C>
+ * @endverbatim
+ * where A is one of A1,A2... that were proposed by the initiator.
+ * The initiator MUST continue with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ * @endverbatim
+ * or, if it requires target authentication, with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ *    CHAP_I=<I>
+ *    CHAP_C=<C>
+ * @endverbatim
+ * If the initiator authentication fails, the target MUST answer with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator required target authentication, the target MUST either
+ * answer with a Login reject with "Authentication Failure" or reply
+ * with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ * @endverbatim
+ * If the target authentication fails, the initiator MUST close the
+ * connection:\n
+ * where N, (A,A1,A2), I, C, and R are (correspondingly) the Name,
+ * Algorithm, Identifier, Challenge, and Response as defined in
+ * RFC1994.\n
+ * N is a text string; A,A1,A2, and I are numbers; C and R are
+ * binary-values. Their binary length (not the length of the character
+ * string that represents them in encoded form) MUST NOT exceed
+ * 1024 bytes. Hex or Base64 encoding may be used for C and R.\n
+ * For the Algorithm, as stated in [RFC1994], one value is required to
+ * be implemented:
+ * @verbatim
+ *    5     (CHAP with MD5)
+ * @endverbatim
+ * To guarantee interoperability, initiators MUST always offer it as one
+ * of the proposed algorithms.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_CHAP_CHAP_N "CHAP_N"
+
+/**
+ * @brief Key used during SecurityNegotiation stage of Login Phase: Challenge Handshake Authentication Protocol (CHAP): CHAP_R.
+ *
+ * For CHAP RFC1994, the initiator MUST use:
+ * @verbatim
+ *    CHAP_A=<A1,A2...>
+ * @endverbatim
+ * where A1,A2... are proposed algorithms, in order of preference.
+ * The target MUST answer with a Login reject with the "Authentication
+ * Failure" status or reply with:
+ * @verbatim
+ *    CHAP_A=<A>
+ *    CHAP_I=<I>
+ *    CHAP_C=<C>
+ * @endverbatim
+ * where A is one of A1,A2... that were proposed by the initiator.
+ * The initiator MUST continue with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ * @endverbatim
+ * or, if it requires target authentication, with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ *    CHAP_I=<I>
+ *    CHAP_C=<C>
+ * @endverbatim
+ * If the initiator authentication fails, the target MUST answer with a
+ * Login reject with "Authentication Failure" status. Otherwise, if the
+ * initiator required target authentication, the target MUST either
+ * answer with a Login reject with "Authentication Failure" or reply
+ * with:
+ * @verbatim
+ *    CHAP_N=<N>
+ *    CHAP_R=<R>
+ * @endverbatim
+ * If the target authentication fails, the initiator MUST close the
+ * connection:\n
+ * where N, (A,A1,A2), I, C, and R are (correspondingly) the Name,
+ * Algorithm, Identifier, Challenge, and Response as defined in
+ * RFC1994.\n
+ * N is a text string; A,A1,A2, and I are numbers; C and R are
+ * binary-values. Their binary length (not the length of the character
+ * string that represents them in encoded form) MUST NOT exceed
+ * 1024 bytes. Hex or Base64 encoding may be used for C and R.\n
+ * For the Algorithm, as stated in [RFC1994], one value is required to
+ * be implemented:
+ * @verbatim
+ *    5     (CHAP with MD5)
+ * @endverbatim
+ * To guarantee interoperability, initiators MUST always offer it as one
+ * of the proposed algorithms.
+ */
+#define ISCSI_LOGIN_AUTH_SECURITY_TEXT_KEY_AUTH_METHOD_CHAP_CHAP_R "CHAP_R"
 
 /* Login/Text Operational Text Keys
 
@@ -1583,1280 +3413,2140 @@ typedef struct __attribute__((packed)) iscsi_text_response_packet {
    a Boolean "or" function with an arbitrary Boolean value (e.g., if the
    offered value is Yes the selected value must be Yes).
 */
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_HEADER_DIGEST "HeaderDigest" // Use: IO
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_DATA_DIGEST   "DataDigest"   // Senders: Initiator and target
-                                                               // Scope: CO
-                                                               // HeaderDigest = <list-of-values>
-                                                               // DataDigest = <list-of-values>
-                                                               // Default is None for both HeaderDigest and DataDigest.
-                                                               // Digests enable the checking of end-to-end, non-cryptographic data
-                                                               // integrity beyond the integrity checks provided by the link layers and
-                                                               // the covering of the whole communication path, including all elements
-                                                               // that may change the network-level PDUs, such as routers, switches,
-                                                               // and proxies.
-                                                               // The following table lists cyclic integrity checksums that can be
-                                                               // negotiated for the digests and MUST be implemented by every iSCSI
-                                                               // initiator and target. These digest options only have error detection
-                                                               // significance.
-                                                               // +---------------------------------------------+
-                                                               // | Name          | Description     | Generator |
-                                                               // +---------------------------------------------+
-                                                               // | CRC32C        | 32-bit CRC      |0x11edc6f41|
-                                                               // +---------------------------------------------+
-                                                               // | None          | no digest                   |
-                                                               // +---------------------------------------------+
-                                                               // The generator polynomial G(x) for this digest is given in hexadecimal
-                                                               // notation (e.g. "0x3b" stands for 0011 1011, and the polynomial is
-                                                               // x**5 + x**4 + x**3 + x + 1).
-                                                               // When the initiator and target agree on a digest, this digest MUST be
-                                                               // used for every PDU in the Full Feature Phase.
-                                                               // Padding bytes, when present in a segment covered by a CRC, SHOULD be
-                                                               // set to 0 and are included in the CRC.
-                                                               // The CRC MUST be calculated by a method that produces the same results
-                                                               // as the following process:
-                                                               // - The PDU bits are considered as the coefficients of a polynomial
-                                                               //   M(x) of degree n - 1; bit 7 of the lowest numbered byte is
-                                                               //   considered the most significant bit (x**n - 1), followed by bit 6
-                                                               //   of the lowest numbered byte through bit 0 of the highest numbered
-                                                               //   byte (x**0).
-                                                               // - The most significant 32 bits are complemented.
-                                                               // - The polynomial is multiplied by x**32, then divided by G(x). The
-                                                               //   generator polynomial produces a remainder R(x) of degree <= 31.
-                                                               // - The coefficients of R(x) are formed into a 32-bit sequence.
-                                                               // - The bit sequence is complemented, and the result is the CRC.
-                                                               // - The CRC bits are mapped into the digest word. The x**31
-                                                               //   coefficient is mapped to bit 7 of the lowest numbered byte of the
-                                                               //   digest, and the mapping continues with successive coefficients and
-                                                               //   bits so that the x**24 coefficient is mapped to bit 0 of the lowest
-                                                               //   numbered byte. The mapping continues further with the x**23
-                                                               //   coefficient mapped to bit 7 of the next byte in the digest until
-                                                               //   the x**0 coefficient is mapped to bit 0 of the highest numbered
-                                                               //   byte of the digest.
-                                                               // - Computing the CRC over any segment (data or header) extended to
-                                                               //   include the CRC built using the generator 0x11edc6f41 will always
-                                                               //   get the value 0x1c2d19ed as its final remainder (R(x)). This value
-                                                               //   is given here in its polynomial form (i.e., not mapped as the
-                                                               //   digest word).
-                                                               // For a discussion about selection criteria for the CRC, see RFC3385.
-                                                               // For a detailed analysis of the iSCSI polynomial, see Castagnoli93.
-                                                               // Private or public extension algorithms MAY also be negotiated for
-                                                               // digests. Whenever a private or public digest extension algorithm is
-                                                               // part of the default offer (the offer made in the absence of explicit
-                                                               // administrative action), the implementer MUST ensure that CRC32C is
-                                                               // listed as an alternative in the default offer and "None" is not part
-                                                               // of the default offer.
-                                                               // Extension digest algorithms MUST be named using one of the following
-                                                               // two formats:
-                                                               //    1) Y-reversed.vendor.dns_name.do_something=
-                                                               //    2) New public key with no name prefix constraints
-                                                               // Digests named using the Y- format are used for private purposes
-                                                               // (unregistered). New public keys must be registered with IANA using
-                                                               // the IETF Review process (RFC5226). New public extensions for
-                                                               // digests MUST NOT use the Y# name prefix.
-                                                               // For private extension digests, to identify the vendor we suggest
-                                                               // using the reversed DNS-name as a prefix to the proper digest names.
-                                                               // The part of digest-name following Y- MUST conform to the format for
-                                                               // standard-label specified.
-                                                               // Support for public or private extension digests is OPTIONA
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_MAX_CONNECTIONS "MaxConnections" // Use: LO
-                                                                   // Senders: Initiator and target
-                                                                   // Scope: SW
-                                                                   // Irrelevant when: SessionType=Discovery
-                                                                   // MaxConnections=<numerical-value-from-1-to-65535>
-                                                                   // Default is 1.
-                                                                   // Result function is Minimum.
-                                                                   // The initiator and target negotiate the maximum number of connections
-                                                                   // requested/acceptable
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_SEND_TARGETS "SendTargets" // Use: FFPO
-                                                             // Senders: Initiator
-                                                             // Scope: SW
-                                                             // The text in this appendix is a normative part of this document.
-                                                             // To reduce the amount of configuration required on an initiator, iSCSI
-                                                             // provides the SendTargets Text Request. The initiator uses the
-                                                             // SendTargets request to get a list of targets to which it may have
-                                                             // access, as well as the list of addresses (IP address and TCP port) on
-                                                             // which these targets may be accessed.
-                                                             // To make use of SendTargets, an initiator must first establish one of
-                                                             // two types of sessions. If the initiator establishes the session
-                                                             // using the key "SessionType=Discovery", the session is a Discovery
-                                                             // session, and a target name does not need to be specified. Otherwise,
-                                                             // the session is a Normal operational session. The SendTargets command
-                                                             // MUST only be sent during the Full Feature Phase of a Normal or
-                                                             // Discovery session.
-                                                             // A system that contains targets MUST support Discovery sessions on
-                                                             // each of its iSCSI IP address-port pairs and MUST support the
-                                                             // SendTargets command on the Discovery session. In a Discovery
-                                                             // session, a target MUST return all path information (IP address-port
-                                                             // pairs and Target Portal Group Tags) for the targets on the target
-                                                             // Network Entity that the requesting initiator is authorized to access.
-                                                             // A target MUST support the SendTargets command on operational
-                                                             // sessions; these will only return path information about the target to
-                                                             // which the session is connected and do not need to return information
-                                                             // about other target names that may be defined in the responding
-                                                             // system.
-                                                             // An initiator MAY make use of the SendTargets command as it sees fit.
-                                                             // A SendTargets command consists of a single Text Request PDU. This
-                                                             // PDU contains exactly one text key and value. The text key MUST be
-                                                             // SendTargets. The expected response depends upon the value, as well
-                                                             // as whether the session is a Discovery session or an operational
-                                                             // session.
-                                                             // The value must be one of:
-                                                             //    All
-                                                             //       The initiator is requesting that information on all relevant
-                                                             //       targets known to the implementation be returned. This value
-                                                             //       MUST be supported on a Discovery session and MUST NOT be
-                                                             //       supported on an operational session.
-                                                             //    <iSCSI-target-name>
-                                                             //       If an iSCSI Target Name is specified, the session should
-                                                             //       respond with addresses for only the named target, if possible.
-                                                             //       This value MUST be supported on Discovery sessions. A
-                                                             //       Discovery session MUST be capable of returning addresses for
-                                                             //       those targets that would have been returned had value=All been
-                                                             //       designated.
-                                                             //    <nothing>
-                                                             //       The session should only respond with addresses for the target
-                                                             //       to which the session is logged in. This MUST be supported on
-                                                             //       operational sessions and MUST NOT return targets other than the
-                                                             //       one to which the session is logged in.
-                                                             // The response to this command is a Text Response that contains a list
-                                                             // of zero or more targets and, optionally, their addresses. Each
-                                                             // target is returned as a target record. A target record begins with
-                                                             // the TargetName text key, followed by a list of TargetAddress text
-                                                             // keys, and bounded by the end of the Text Response or the next
-                                                             // TargetName key, which begins a new record. No text keys other than
-                                                             // TargetName and TargetAddress are permitted within a SendTargets
-                                                             // response.
-                                                             // A Discovery session MAY respond to a SendTargets request with its
-                                                             // complete list of targets, or with a list of targets that is based on
-                                                             // the name of the initiator logged in to the session.
-                                                             // A SendTargets response MUST NOT contain target names if there are no
-                                                             // targets for the requesting initiator to access.
-                                                             // Each target record returned includes zero or more TargetAddress
-                                                             // fields.
-                                                             // Each target record starts with one text key of the form:
-                                                             //    TargetName=<target-name-goes-here>
-                                                             // followed by zero or more address keys of the form:
-                                                             // TargetAddress=<hostname-or-ipaddress>[:<tcp-port>],
-                                                             //    <portal-group-tag>
-                                                             // The hostname-or-ipaddress contains a domain name, IPv4 address, or
-                                                             // IPv6 address (RFC4291), as specified for the TargetAddress key.
-                                                             // A hostname-or-ipaddress duplicated in TargetAddress responses for a
-                                                             // given node (the port is absent or equal) would probably indicate that
-                                                             // multiple address families are in use at once (IPv6 and IPv4).
-                                                             // Each TargetAddress belongs to a portal group, identified by its
-                                                             // numeric Target Portal Group Tag. The iSCSI Target
-                                                             // Name, together with this tag, constitutes the SCSI port identifier;
-                                                             // the tag only needs to be unique within a given target's name list of
-                                                             // addresses.
-                                                             // Multiple-connection sessions can span iSCSI addresses that belong to
-                                                             // the same portal group.
-                                                             // Multiple-connection sessions cannot span iSCSI addresses that belong
-                                                             // to different portal groups.
-                                                             // If a SendTargets response reports an iSCSI address for a target, it
-                                                             // SHOULD also report all other addresses in its portal group in the
-                                                             // same response.
-                                                             // A SendTargets Text Response can be longer than a single Text Response
-                                                             // PDU and makes use of the long Text Responses as specified.
-                                                             // After obtaining a list of targets from the Discovery session, an
-                                                             // iSCSI initiator may initiate new sessions to log in to the discovered
-                                                             // targets for full operation. The initiator MAY keep the Discovery
-                                                             // session open and MAY send subsequent SendTargets commands to discover
-                                                             // new targets.
-                                                             // Examples:
-                                                             // This example is the SendTargets response from a single target that
-                                                             // has no other interface ports.
-                                                             // The initiator sends a Text Request that contains:
-                                                             //    SendTargets=All
-                                                             // The target sends a Text Response that contains:
-                                                             //    TargetName=iqn.1993-11.de.uni-freiburg:diskarray.sn.8675309
-                                                             // All the target had to return in this simple case was the target name.
-                                                             // It is assumed by the initiator that the IP address and TCP port for
-                                                             // this target are the same as those used on the current connection to
-                                                             // the default iSCSI target.
-                                                             // The next example has two internal iSCSI targets, each accessible via
-                                                             // two different ports with different IP addresses. The following is
-                                                             // the Text Response:
-                                                             //    TargetName=iqn.1993-11.de.uni-freiburg:diskarray.sn.8675309
-                                                             //    TargetAddress=10.1.0.45:5300,1
-                                                             //    TargetAddress=10.1.1.45:5300,2
-                                                             //    TargetName=iqn.1993-11.de.uni-freiburg:diskarray.sn.1234567
-                                                             //    TargetAddress=10.1.0.45:5300,1
-                                                             //    TargetAddress=10.1.1.45:5300,2
-                                                             // Both targets share both addresses; the multiple addresses are likely
-                                                             // used to provide multi-path support. The initiator may connect to
-                                                             // either target name on either address. Each of the addresses has its
-                                                             // own Target Portal Group Tag; they do not support spanning multiple-
-                                                             // connection sessions with each other. Keep in mind that the Target
-                                                             // Portal Group Tags for the two named targets are independent of one
-                                                             // another; portal group "1" on the first target is not necessarily the
-                                                             // same as portal group "1" on the second target.
-                                                             // In the above example, a DNS host name or an IPv6 address could have
-                                                             // been returned instead of an IPv4 address.
-                                                             // The next Text Response shows a target that supports spanning sessions
-                                                             // across multiple addresses and further illustrates the use of the
-                                                             // Target Portal Group Tags:
-                                                             //    TargetName=iqn.1993-11.de.uni-freiburg:diskarray.sn.8675309
-                                                             //    TargetAddress=10.1.0.45:5300,1
-                                                             //    TargetAddress=10.1.1.46:5300,1
-                                                             //    TargetAddress=10.1.0.47:5300,2
-                                                             //    TargetAddress=10.1.1.48:5300,2
-                                                             //    TargetAddress=10.1.1.49:5300,3
-                                                             // In this example, any of the target addresses can be used to reach the
-                                                             // same target. A single-connection session can be established to any
-                                                             // of these TCP addresses. A multiple-connection session could span
-                                                             // addresses .45 and .46 or .47 and .48 but cannot span any other
-                                                             // combination. A TargetAddress with its own tag (.49) cannot be
-                                                             // combined with any other address within the same session.
-                                                             // This SendTargets response does not indicate whether .49 supports
-                                                             // multiple connections per session; it is communicated via the
-                                                             // MaxConnections text key upon login to the target
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_INITIAL_R2T "InitialR2T" // Use: LO
-                                                           // Senders: Initiator and target
-                                                           // Scope: SW
-                                                           // Irrelevant when: SessionType=Discovery
-                                                           // InitialR2T=<boolean-value>
-                                                           // Examples:
-                                                           //    I->InitialR2T=No
-                                                           //    T->InitialR2T=No
-                                                           // Default is Yes.
-                                                           // Result function is OR.
-                                                           // The InitialR2T key is used to turn off the default use of R2T for
-                                                           // unidirectional operations and the output part of bidirectional
-                                                           // commands, thus allowing an initiator to start sending data to a
-                                                           // target as if it has received an initial R2T with Buffer
-                                                           // Offset=Immediate Data Length and Desired Data Transfer
-                                                           // Length=(min(FirstBurstLength, Expected Data Transfer Length) -
-                                                           // Received Immediate Data Length).
-                                                           // The default action is that R2T is required, unless both the initiator
-                                                           // and the target send this key-pair attribute specifying InitialR2T=No.
-                                                           // Only the first outgoing data burst (immediate data and/or separate
-                                                           // PDUs) can be sent unsolicited (i.e., not requiring an explicit R2T)
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_IMMEDIATE_DATA "ImmediateData" // Use: LO
-                                                                 // Senders: Initiator and target
-                                                                 // Scope: SW
-                                                                 // Irrelevant when: SessionType=Discovery
-                                                                 // ImmediateData=<boolean-value>
-                                                                 // Default is Yes.
-                                                                 // Result function is AND.
-                                                                 // The initiator and target negotiate support for immediate dataTo
-                                                                 // turn immediate data off, the initiator or target must state its
-                                                                 // desire to do soImmediateData can be turned on if both the
-                                                                 // initiator and target have ImmediateData=Yes.
-                                                                 // If ImmediateData is set to Yes and InitialR2T is set to Yes
-                                                                 // (default), then only immediate data are accepted in the first burst.
-                                                                 // If ImmediateData is set to No and InitialR2T is set to Yes, then the
-                                                                 // initiator MUST NOT send unsolicited data and the target MUST reject
-                                                                 // unsolicited data with the corresponding response code.
-                                                                 // If ImmediateData is set to No and InitialR2T is set to No, then the
-                                                                 // initiator MUST NOT send unsolicited immediate data but MAY send one
-                                                                 // unsolicited burst of Data-OUT PDUs.
-                                                                 // If ImmediateData is set to Yes and InitialR2T is set to No, then the
-                                                                 // initiator MAY send unsolicited immediate data and/or one unsolicited
-                                                                 // burst of Data-OUT PDUs.
-                                                                 // The following table is a summary of unsolicited data options:
-                                                                 // +----------+-------------+------------------+-------------+
-                                                                 // |InitialR2T|ImmediateData|    Unsolicited   |ImmediateData|
-                                                                 // |          |             |   Data-Out PDUs  |             |
-                                                                 // +----------+-------------+------------------+-------------+
-                                                                 // | No       | No          | Yes              | No          |
-                                                                 // +----------+-------------+------------------+-------------+
-                                                                 // | No       | Yes         | Yes              | Yes         |
-                                                                 // +----------+-------------+------------------+-------------+
-                                                                 // | Yes      | No          | No               | No          |
-                                                                 // +----------+-------------+------------------+-------------+
-                                                                 // | Yes      | Yes         | No               | Yes         |
-                                                                 // +----------+-------------+------------------+-------------+
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_MAX_RECV_DS_LEN "MaxRecvDataSegmentLength" // Use: ALL, Declarative
-                                                                             // Senders: Initiator and target
-                                                                             // Scope: CO
-                                                                             // MaxRecvDataSegmentLength=<numerical-value-512-to-(2**24 - 1)>
-                                                                             // Default is 8192 bytes.
-                                                                             // The initiator or target declares the maximum data segment length in
-                                                                             // bytes it can receive in an iSCSI PDU.
-                                                                             // The transmitter (initiator or target) is required to send PDUs with a
-                                                                             // data segment that does not exceed MaxRecvDataSegmentLength of the
-                                                                             // receiver.
-                                                                             // A target receiver is additionally limited by MaxBurstLength for
-                                                                             // solicited data and FirstBurstLength for unsolicited dataAn
-                                                                             // initiator MUST NOT send solicited PDUs exceeding MaxBurstLength nor
-                                                                             // unsolicited PDUs exceeding FirstBurstLength (or FirstBurstLength-
-                                                                             // Immediate Data Length if immediate data were sent)
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_MAX_BURST_LEN "MaxBurstLength" // Use: LO
-                                                                 // Senders: Initiator and target
-                                                                 // Scope: SW
-                                                                 // Irrelevant when: SessionType=Discovery
-                                                                 // MaxBurstLength=<numerical-value-512-to-(2**24 - 1)>
-                                                                 // Default is 262144 (256 KB).
-                                                                 // Result function is Minimum.
-                                                                 // The initiator and target negotiate the maximum SCSI data payload in
-                                                                 // bytes in a Data-In or a solicited Data-Out iSCSI sequence. A
-                                                                 // sequence consists of one or more consecutive Data-In or Data-Out PDUs
-                                                                 // that end with a Data-In or Data-Out PDU with the F bit set to 1
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_FIRST_BURST_LEN "FirstBurstLength" // Use: LO
-                                                                     // Senders: Initiator and target
-                                                                     // Scope: SW
-                                                                     // Irrelevant when: SessionType=Discovery
-                                                                     // Irrelevant when: ( InitialR2T=Yes and ImmediateData=No )
-                                                                     // FirstBurstLength=<numerical-value-512-to-(2**24 - 1)>
-                                                                     // Default is 65536 (64 KB).
-                                                                     // Result function is Minimum.
-                                                                     // The initiator and target negotiate the maximum amount in bytes of
-                                                                     // unsolicited data an iSCSI initiator may send to the target during the
-                                                                     // execution of a single SCSI command. This covers the immediate data
-                                                                     // (if any) and the sequence of unsolicited Data-Out PDUs (if any) that
-                                                                     // follow the command.
-                                                                     // FirstBurstLength MUST NOT exceed MaxBurstLength
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_DEFAULT_TIME_WAIT "DefaultTime2Wait" // Use: LO
-                                                                       // Senders: Initiator and target
-                                                                       // Scope: SW
-                                                                       // DefaultTime2Wait=<numerical-value-0-to-3600>
-                                                                       // Default is 2.
-                                                                       // Result function is Maximum.
-                                                                       // The initiator and target negotiate the minimum time, in seconds, to
-                                                                       // wait before attempting an explicit/implicit logout or an active task
-                                                                       // reassignment after an unexpected connection termination or a
-                                                                       // connection reset.
-                                                                       // A value of 0 indicates that logout or active task reassignment can be
-                                                                       // attempted immediately
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_DEFAULT_TIME_RETAIN "DefaultTime2Retain" // Use: LO
-                                                                           // Senders: Initiator and target
-                                                                           // Scope: SW
-                                                                           // DefaultTime2Retain=<numerical-value-0-to-3600>
-                                                                           // Default is 20.
-                                                                           // Result function is Minimum.
-                                                                           // The initiator and target negotiate the maximum time, in seconds,
-                                                                           // after an initial wait (Time2Wait), before which an active task
-                                                                           // reassignment is still possible after an unexpected connection
-                                                                           // termination or a connection reset.
-                                                                           // This value is also the session state timeout if the connection in
-                                                                           // question is the last LOGGED_IN connection in the session.
-                                                                           // A value of 0 indicates that connection/task state is immediately
-                                                                           // discarded by the target
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_MAX_OUTSTANDING_R2T "MaxOutstandingR2T" // Use: LO
-                                                                          // Senders: Initiator and target
-                                                                          // Scope: SW
-                                                                          // MaxOutstandingR2T=<numerical-value-from-1-to-65535>
-                                                                          // Irrelevant when: SessionType=Discovery
-                                                                          // Default is 1.
-                                                                          // Result function is Minimum.
-                                                                          // The initiator and target negotiate the maximum number of outstanding
-                                                                          // R2Ts per task, excluding any implied initial R2T that might be part
-                                                                          // of that task. An R2T is considered outstanding until the last data
-                                                                          // PDU (with the F bit set to 1) is transferred or a sequence reception
-                                                                          // timeout is encountered for that data sequence
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_DATA_PDU_IN_ORDER "DataPDUInOrder" // Use: LO
-                                                                     // Senders: Initiator and target
-                                                                     // Scope: SW
-                                                                     // Irrelevant when: SessionType=Discovery
-                                                                     // DataPDUInOrder=<boolean-value>
-                                                                     // Default is Yes.
-                                                                     // Result function is OR.
-                                                                     // "No" is used by iSCSI to indicate that the data PDUs within sequences
-                                                                     // can be in any order. "Yes" is used to indicate that data PDUs within
-                                                                     // sequences have to be at continuously increasing addresses and
-                                                                     // overlays are forbidden
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_DATA_SEQ_IN_ORDER "DataSequenceInOrder" // Use: LO
-                                                                          // Senders: Initiator and target
-                                                                          // Scope: SW
-                                                                          // Irrelevant when: SessionType=Discovery
-                                                                          // DataSequenceInOrder=<boolean-value>
-                                                                          // Default is Yes.
-                                                                          // Result function is OR.
-                                                                          // A data sequence is a sequence of Data-In or Data-Out PDUs that end
-                                                                          // with a Data-In or Data-Out PDU with the F bit set to 1. A Data-Out
-                                                                          // sequence is sent either unsolicited or in response to an R2T.
-                                                                          // Sequences cover an offset-range.
-                                                                          // If DataSequenceInOrder is set to No, data PDU sequences may be
-                                                                          // transferred in any order.
-                                                                          // If DataSequenceInOrder is set to Yes, data sequences MUST be
-                                                                          // transferred using continuously non-decreasing sequence offsets (R2T
-                                                                          // buffer offset for writes, or the smallest SCSI Data-In buffer offset
-                                                                          // within a read data sequence).
-                                                                          // If DataSequenceInOrder is set to Yes, a target may retry at most the
-                                                                          // last R2T, and an initiator may at most request retransmission for the
-                                                                          // last read data sequence. For this reason, if ErrorRecoveryLevel is
-                                                                          // not 0 and DataSequenceInOrder is set to Yes, then MaxOutstandingR2T
-                                                                          // MUST be set to 1
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_ERR_RECOVERY_LEVEL "ErrorRecoveryLevel" // Use: LO
-                                                                          // Senders: Initiator and target
-                                                                          // Scope: SW
-                                                                          // ErrorRecoveryLevel=<numerical-value-0-to-2>
-                                                                          // Default is 0.
-                                                                          // Result function is Minimum.
-                                                                          // The initiator and target negotiate the recovery level supported.
-                                                                          // Recovery levels represent a combination of recovery capabilities.
-                                                                          // Each recovery level includes all the capabilities of the lower
-                                                                          // recovery levels and adds some new ones to them.
-                                                                          // In the description of recovery mechanisms, certain recovery classes
-                                                                          // are specified
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_PRIV_EXT_KEY_FMT "X-reversed.vendor" // Use: ALL
-                                                                       // Senders: Initiator and target
-                                                                       // Scope: specific key dependent
-                                                                       // X-reversed.vendor.dns_name.do_something=
-                                                                       // Keys with this format are used for private extension purposes. These
-                                                                       // keys always start with X- if unregistered with IANA (private). New
-                                                                       // public keys (if registered with IANA via an IETF Review RFC5226) no
-                                                                       // longer have an X# name prefix requirement; implementers may propose
-                                                                       // any intuitive unique name.
-                                                                       // For unregistered keys, to identify the vendor we suggest using the
-                                                                       // reversed DNS-name as a prefix to the key-proper.
-                                                                       // The part of key-name following X- MUST conform to the format for
-                                                                       // key-name.
-                                                                       // Vendor-specific keys MUST ONLY be used in Normal sessions.
-                                                                       // Support for public or private extension keys is OPTIONAL
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_TASK_REPORTING "TaskReporting" // Use: LO
-                                                                 // Senders: Initiator and target
-                                                                 // Scope: SW
-                                                                 // Irrelevant when: SessionType=Discovery
-                                                                 // TaskReporting=<list-of-values>
-                                                                 // Default is RFC3720.
-                                                                 // This key is used to negotiate the task completion reporting semantics
-                                                                 // from the SCSI target. The following table describes the semantics
-                                                                 // that an iSCSI target MUST support for respective negotiated key
-                                                                 // values. Whenever this key is negotiated, at least the RFC3720 and
-                                                                 // ResponseFence values MUST be offered as options by the negotiation
-                                                                 // originator.
-                                                                 // +--------------+------------------------------------------+
-                                                                 // | Name         |             Description                  |
-                                                                 // +--------------+------------------------------------------+
-                                                                 // | RFC3720      | RFC 3720-compliant semantics. Response   |
-                                                                 // |              | fencing is not guaranteed, and fast      |
-                                                                 // |              | completion of multi-task aborting is not |
-                                                                 // |              | supported.                               |
-                                                                 // +--------------+------------------------------------------+
-                                                                 // | ResponseFence| Response Fence                           |
-                                                                 // |              | semantics MUST be supported in reporting |
-                                                                 // |              | task completions.                        |
-                                                                 // +--------------+------------------------------------------+
-                                                                 // | FastAbort    | Updated fast multi-task abort semantics  |
-                                                                 // |              | defined in MUST be supported. Support    |
-                                                                 // |              | for the Response. Fence is implied -     |
-                                                                 // |              | i.e., semantics MUST be supported as     |
-                                                                 // |              | well.                                    |
-                                                                 // +--------------+------------------------------------------+
-                                                                 // When TaskReporting is not negotiated to FastAbort, the
-                                                                 // standard multi-task abort semantics MUST be used
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_X_NODE_ARCH "X#NodeArchitecture" // Use: LO, Declarative
-                                                                   // Senders: Initiator and target
-                                                                   // Scope: SW
-                                                                   // X#NodeArchitecture=<list-of-values>
-                                                                   // Default is None.
-                                                                   // Examples:
-                                                                   //    X#NodeArchitecture=ExampleOS/v1234,ExampleInc_SW_Initiator/1.05a
-                                                                   //    X#NodeArchitecture=ExampleInc_HW_Initiator/4010,Firmware/2.0.0.5
-                                                                   //    X#NodeArchitecture=ExampleInc_SW_Initiator/2.1,CPU_Arch/i686
-                                                                   // This document does not define the structure or content of the list of
-                                                                   // values.
-                                                                   // The initiator or target declares the details of its iSCSI node
-                                                                   // architecture to the remote endpoint. These details may include, but
-                                                                   // are not limited to, iSCSI vendor software, firmware, or hardware
-                                                                   // versions; the OS version; or hardware architecture. This key may be
-                                                                   // declared on a Discovery session or a Normal session.
-                                                                   // The length of the key value (total length of the list-of-values) MUST
-                                                                   // NOT be greater than 255 bytes.
-                                                                   // X#NodeArchitecture MUST NOT be redeclared during the Login Phase.
-                                                                   // Functional behavior of the iSCSI node (this includes the iSCSI
-                                                                   // protocol logic - the SCSI, iSCSI, and TCP/IP protocols) MUST NOT
-                                                                   // depend on the presence, absence, or content of the X#NodeArchitecture
-                                                                   // key. The key MUST NOT be used by iSCSI nodes for interoperability or
-                                                                   // for exclusion of other nodes. To ensure proper use, key values
-                                                                   // SHOULD be set by the node itself, and there SHOULD NOT be provisions
-                                                                   // for the key values to contain user-defined text.
-                                                                   // Nodes implementing this key MUST choose one of the following
-                                                                   // implementation options:
-                                                                   // - only transmit the key,
-                                                                   // - only log the key values received from other nodes, or
-                                                                   // - both transmit and log the key values.
-                                                                   // Each node choosing to implement transmission of the key values MUST
-                                                                   // be prepared to handle the response of iSCSI nodes that do not
-                                                                   // understand the key.
-                                                                   // Nodes that implement transmission and/or logging of the key values
-                                                                   // may also implement administrative mechanisms that disable and/or
-                                                                   // change the logging and key transmission details.
-                                                                   // Thus, a valid behavior for this key may be that a node is completely
-                                                                   // silent (the node does not transmit any key value and simply discards
-                                                                   // any key values it receives without issuing a NotUnderstood response)
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_IF_MARKER   "IFMarker"  // Obsoleted Keys
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_OF_MARKER   "OFMarker"  // This document obsoletes the following keys defined in RFC3720:
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_OF_MARK_INT "OFMarkInt" // IFMarker, OFMarker, OFMarkInt, and IFMarkInt. However, iSCSI
-#define ISCSI_LOGIN_AUTH_TEXT_KEY_IF_MARK_INT "IFMarkInt" // implementations compliant to this document may still receive these
-                                                          // obsoleted keys - i.e., in a responder role - in a text negotiation.
-                                                          // When an IFMarker or OFMarker key is received, a compliant iSCSI
-                                                          // implementation SHOULD respond with the constant "Reject" value. The
-                                                          // implementation MAY alternatively respond with a "No" value.
-                                                          // However, the implementation MUST NOT respond with a "NotUnderstood"
-                                                          // value for either of these keys.
-                                                          // When an IFMarkInt or OFMarkInt key is received, a compliant iSCSI
-                                                          // implementation MUST respond with the constant "Reject" value. The
-                                                          // implementation MUST NOT respond with a "NotUnderstood" value for
-                                                          // either of these keys
-
-/* This is an initiator-defined component of the session identifier and
-   is structured as follows:
-
-   For the T field values 00b and 01b, a combination of A and B (for
-   00b) or B and C (for 01b) identifies the vendor or organization whose
-   component (software or hardware) generates this ISID. A vendor or
-   organization with one or more OUIs, or one or more Enterprise
-   Numbers, MUST use at least one of these numbers and select the
-   appropriate value for the T field when its components generate ISIDs.
-   An OUI or EN MUST be set in the corresponding fields in network byte
-   order (byte big-endian).
-
-   If the T field is 10b, B and C are set to a random 24-bit unsigned
-   integer value in network byte order (byte big-endian).
-
-   The Qualifier field is a 16-bit or 24-bit unsigned integer value that
-   provides a range of possible values for the ISID within the selected
-   namespace. It may be set to any value within the constraints
-   specified in the iSCSI protocol.
-
-   If the ISID is derived from something assigned to a hardware adapter
-   or interface by a vendor as a preset default value, it MUST be
-   configurable to a value assigned according to the SCSI port behavior
-   desired by the system in which it is installed. The resultant ISID
-   MUST also be persistent over power cycles, reboot, card swap, etc.
-*/
-typedef struct __attribute__((packed)) iscsi_isid {
-    uint8_t a; // Meaning depends on T bit (see above)
-    uint16_t b; // Meaning depends on T bit (see above)
-    uint8_t c; // Meaning depends on T bit (see above)
-    uint16_t d; // Meaning depends on T bit (see above)
-} iscsi_isid;
 
-#define ISCSI_LOGIN_REQ_FLAGS_NEXT_STAGE_SECURITY_NEGOTIATION          0x0 // SecurityNegotiation
-#define ISCSI_LOGIN_REQ_FLAGS_NEXT_STAGE_LOGIN_OPERATIONAL_NEGOTIATION 0x1 // LoginOperationalNegotiation
-#define ISCSI_LOGIN_REQ_FLAGS_NEXT_STAGE_FULL_FEATURE_PHASE            0x3 // FullFeaturePhase
-#define ISCSI_LOGIN_REQ_FLAGS_NEXT_STAGE    (1 << 0) // (NSG) - Two bits - the Login negotiation requests and responses are
-                                                     // associated with a specific stage in the session (SecurityNegotiation,
-                                                     // LoginOperationalNegotiation, FullFeaturePhase) and may indicate the
-                                                     // next stage to which they want to move. The Next Stage value is only
-                                                     // valid when the T bit is 1; otherwise, it is reserved
+/**
+ * @brief Login/Text Operational Session Text Key: Header digest.
+ *
+ * @verbatim
+ * Use: IO
+ * Senders: Initiator and target
+ * Scope: CO
+ * HeaderDigest = <list-of-values>
+ * Default is None for HeaderDigest.
+ * @endverbatim
+ * Digests enable the checking of end-to-end, non-cryptographic data
+ * integrity beyond the integrity checks provided by the link layers and
+ * the covering of the whole communication path, including all elements
+ * that may change the network-level PDUs, such as routers, switches,
+ * and proxies.\n
+ * The following table lists cyclic integrity checksums that can be
+ * negotiated for the digests and MUST be implemented by every iSCSI
+ * initiator and target. These digest options only have error detection
+ * significance.
+ * Name   | Description | Generator
+ * :----- | :---------- | :----------
+ * CRC32C | 32-bit CRC  | 0x11EDC6F41
+ * None   | no digest   ||
+ *
+ * The generator polynomial G(x) for this digest is given in hexadecimal
+ * notation (e.g. "0x3b" stands for 0011 1011, and the polynomial is
+ * x**5 + x**4 + x**3 + x + 1).\n
+ * When the initiator and target agree on a digest, this digest MUST be
+ * used for every PDU in the Full Feature Phase.\n
+ * Padding bytes, when present in a segment covered by a CRC, SHOULD be
+ * set to 0 and are included in the CRC.\n
+ * The CRC MUST be calculated by a method that produces the same results
+ * as the following process:
+ * - The PDU bits are considered as the coefficients of a polynomial
+ *   M(x) of degree n - 1; bit 7 of the lowest numbered byte is
+ *   considered the most significant bit (x**n - 1), followed by bit 6
+ *   of the lowest numbered byte through bit 0 of the highest numbered
+ *   byte (x**0).
+ * - The most significant 32 bits are complemented.
+ * - The polynomial is multiplied by x**32, then divided by G(x). The
+ *   generator polynomial produces a remainder R(x) of degree <= 31.
+ * - The coefficients of R(x) are formed into a 32-bit sequence.
+ * - The bit sequence is complemented, and the result is the CRC.
+ * - The CRC bits are mapped into the digest word. The x**31
+ *   coefficient is mapped to bit 7 of the lowest numbered byte of the
+ *   digest, and the mapping continues with successive coefficients and
+ *   bits so that the x**24 coefficient is mapped to bit 0 of the lowest
+ *   numbered byte. The mapping continues further with the x**23
+ *   coefficient mapped to bit 7 of the next byte in the digest until
+ *   the x**0 coefficient is mapped to bit 0 of the highest numbered
+ *   byte of the digest.
+ * - Computing the CRC over any segment (data or header) extended to
+ *   include the CRC built using the generator 0x11edc6f41 will always
+ *   get the value 0x1c2d19ed as its final remainder (R(x)). This value
+ *   is given here in its polynomial form (i.e., not mapped as the
+ *   digest word).
+ *
+ * For a discussion about selection criteria for the CRC, see RFC3385.\n
+ * For a detailed analysis of the iSCSI polynomial, see Castagnoli93.\n
+ * Private or public extension algorithms MAY also be negotiated for
+ * digests. Whenever a private or public digest extension algorithm is
+ * part of the default offer (the offer made in the absence of explicit
+ * administrative action), the implementer MUST ensure that CRC32C is
+ * listed as an alternative in the default offer and "None" is not part
+ * of the default offer.\n
+ * Extension digest algorithms MUST be named using one of the following
+ * two formats:
+ *    1. Y-reversed.vendor.dns_name.do_something=
+ *    2. New public key with no name prefix constraints
+ *
+ * Digests named using the Y- format are used for private purposes
+ * (unregistered). New public keys must be registered with IANA using
+ * the IETF Review process (RFC5226). New public extensions for
+ * digests MUST NOT use the Y# name prefix.\n
+ * For private extension digests, to identify the vendor we suggest
+ * using the reversed DNS-name as a prefix to the proper digest names.\n
+ * The part of digest-name following Y- MUST conform to the format for
+ * standard-label specified.\n
+ * Support for public or private extension digests is OPTIONAL.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_HEADER_DIGEST "HeaderDigest"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Data digest.
+ *
+ * @verbatim
+ * Use: IO
+ * Senders: Initiator and target
+ * Scope: CO
+ * DataDigest = <list-of-values>
+ * Default is None for DataDigest.
+ * @endverbatim
+ * Digests enable the checking of end-to-end, non-cryptographic data
+ * integrity beyond the integrity checks provided by the link layers and
+ * the covering of the whole communication path, including all elements
+ * that may change the network-level PDUs, such as routers, switches,
+ * and proxies.\n
+ * The following table lists cyclic integrity checksums that can be
+ * negotiated for the digests and MUST be implemented by every iSCSI
+ * initiator and target. These digest options only have error detection
+ * significance.
+ * Name   | Description | Generator
+ * :----- | :---------- | :----------
+ * CRC32C | 32-bit CRC  | 0x11EDC6F41
+ * None   | no digest   ||
+ *
+ * The generator polynomial G(x) for this digest is given in hexadecimal
+ * notation (e.g. "0x3b" stands for 0011 1011, and the polynomial is
+ * x**5 + x**4 + x**3 + x + 1).\n
+ * When the initiator and target agree on a digest, this digest MUST be
+ * used for every PDU in the Full Feature Phase.\n
+ * Padding bytes, when present in a segment covered by a CRC, SHOULD be
+ * set to 0 and are included in the CRC.\n
+ * The CRC MUST be calculated by a method that produces the same results
+ * as the following process:
+ * - The PDU bits are considered as the coefficients of a polynomial
+ *   M(x) of degree n - 1; bit 7 of the lowest numbered byte is
+ *   considered the most significant bit (x**n - 1), followed by bit 6
+ *   of the lowest numbered byte through bit 0 of the highest numbered
+ *   byte (x**0).
+ * - The most significant 32 bits are complemented.
+ * - The polynomial is multiplied by x**32, then divided by G(x). The
+ *   generator polynomial produces a remainder R(x) of degree <= 31.
+ * - The coefficients of R(x) are formed into a 32-bit sequence.
+ * - The bit sequence is complemented, and the result is the CRC.
+ * - The CRC bits are mapped into the digest word. The x**31
+ *   coefficient is mapped to bit 7 of the lowest numbered byte of the
+ *   digest, and the mapping continues with successive coefficients and
+ *   bits so that the x**24 coefficient is mapped to bit 0 of the lowest
+ *   numbered byte. The mapping continues further with the x**23
+ *   coefficient mapped to bit 7 of the next byte in the digest until
+ *   the x**0 coefficient is mapped to bit 0 of the highest numbered
+ *   byte of the digest.
+ * - Computing the CRC over any segment (data or header) extended to
+ *   include the CRC built using the generator 0x11edc6f41 will always
+ *   get the value 0x1c2d19ed as its final remainder (R(x)). This value
+ *   is given here in its polynomial form (i.e., not mapped as the
+ *   digest word).
+ *
+ * For a discussion about selection criteria for the CRC, see RFC3385.\n
+ * For a detailed analysis of the iSCSI polynomial, see Castagnoli93.\n
+ * Private or public extension algorithms MAY also be negotiated for
+ * digests. Whenever a private or public digest extension algorithm is
+ * part of the default offer (the offer made in the absence of explicit
+ * administrative action), the implementer MUST ensure that CRC32C is
+ * listed as an alternative in the default offer and "None" is not part
+ * of the default offer.\n
+ * Extension digest algorithms MUST be named using one of the following
+ * two formats:
+ *    1. Y-reversed.vendor.dns_name.do_something=
+ *    2. New public key with no name prefix constraints
+ *
+ * Digests named using the Y- format are used for private purposes
+ * (unregistered). New public keys must be registered with IANA using
+ * the IETF Review process (RFC5226). New public extensions for
+ * digests MUST NOT use the Y# name prefix.\n
+ * For private extension digests, to identify the vendor we suggest
+ * using the reversed DNS-name as a prefix to the proper digest names.\n
+ * The part of digest-name following Y- MUST conform to the format for
+ * standard-label specified.\n
+ * Support for public or private extension digests is OPTIONAL.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_DATA_DIGEST   "DataDigest"
+
+/**
+ * @brief Login/Text Operational Session Text Key: New connections.
+ *
+ * @verbatim
+ * Use: LO
+ * Senders: Initiator and target
+ * Scope: SW
+ * Irrelevant when: SessionType=Discovery
+ * MaxConnections=<numerical-value-from-1-to-65535>
+ * Default is 1.
+ * @endverbatim
+ * Result function is Minimum.\n
+ * The initiator and target negotiate the maximum number of connections
+ * requested/acceptable.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_MAX_CONNECTIONS "MaxConnections"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Send targets.
+ *
+ * @verbatim
+ * Use: FFPO
+ * Senders: Initiator
+ * Scope: SW
+ * @endverbatim
+ * The text in this appendix is a normative part of this document.\n
+ * To reduce the amount of configuration required on an initiator, iSCSI
+ * provides the SendTargets Text Request. The initiator uses the
+ * SendTargets request to get a list of targets to which it may have
+ * access, as well as the list of addresses (IP address and TCP port) on
+ * which these targets may be accessed.\n
+ * To make use of SendTargets, an initiator must first establish one of
+ * two types of sessions. If the initiator establishes the session
+ * using the key "SessionType=Discovery", the session is a Discovery
+ * session, and a target name does not need to be specified. Otherwise,
+ * the session is a Normal operational session. The SendTargets command
+ * MUST only be sent during the Full Feature Phase of a Normal or
+ * Discovery session.\n
+ * A system that contains targets MUST support Discovery sessions on
+ * each of its iSCSI IP address-port pairs and MUST support the
+ * SendTargets command on the Discovery session. In a Discovery
+ * session, a target MUST return all path information (IP address-port
+ * pairs and Target Portal Group Tags) for the targets on the target
+ * Network Entity that the requesting initiator is authorized to access.\n
+ * A target MUST support the SendTargets command on operational
+ * sessions; these will only return path information about the target to
+ * which the session is connected and do not need to return information
+ * about other target names that may be defined in the responding
+ * system.\n
+ * An initiator MAY make use of the SendTargets command as it sees fit.\n
+ * A SendTargets command consists of a single Text Request PDU. This
+ * PDU contains exactly one text key and value. The text key MUST be
+ * SendTargets. The expected response depends upon the value, as well
+ * as whether the session is a Discovery session or an operational
+ * session.\n
+ * The value must be one of:
+ * @verbatim
+ *    All
+ *       The initiator is requesting that information on all relevant
+ *       targets known to the implementation be returned. This value
+ *       MUST be supported on a Discovery session and MUST NOT be
+ *       supported on an operational session.
+ *    <iSCSI-target-name>
+ *       If an iSCSI Target Name is specified, the session should
+ *       respond with addresses for only the named target, if possible.
+ *       This value MUST be supported on Discovery sessions. A
+ *       Discovery session MUST be capable of returning addresses for
+ *       those targets that would have been returned had value=All been
+ *       designated.
+ *    <nothing>
+ *       The session should only respond with addresses for the target
+ *       to which the session is logged in. This MUST be supported on
+ *       operational sessions and MUST NOT return targets other than the
+ *       one to which the session is logged in.
+ * @endverbatim
+ * The response to this command is a Text Response that contains a list
+ * of zero or more targets and, optionally, their addresses. Each
+ * target is returned as a target record. A target record begins with
+ * the TargetName text key, followed by a list of TargetAddress text
+ * keys, and bounded by the end of the Text Response or the next
+ * TargetName key, which begins a new record. No text keys other than
+ * TargetName and TargetAddress are permitted within a SendTargets
+ * response.\n
+ * A Discovery session MAY respond to a SendTargets request with its
+ * complete list of targets, or with a list of targets that is based on
+ * the name of the initiator logged in to the session.\n
+ * A SendTargets response MUST NOT contain target names if there are no
+ * targets for the requesting initiator to access.\n
+ * Each target record returned includes zero or more TargetAddress
+ * fields.\n
+ * Each target record starts with one text key of the form:
+ * @verbatim
+ *    TargetName=<target-name-goes-here>
+ * @endverbatim
+ * followed by zero or more address keys of the form:
+ * @verbatim
+ * TargetAddress=<hostname-or-ipaddress>[:<tcp-port>],
+ *    <portal-group-tag>
+ * @endverbatim
+ * The hostname-or-ipaddress contains a domain name, IPv4 address, or
+ * IPv6 address (RFC4291), as specified for the TargetAddress key.\n
+ * A hostname-or-ipaddress duplicated in TargetAddress responses for a
+ * given node (the port is absent or equal) would probably indicate that
+ * multiple address families are in use at once (IPv6 and IPv4).\n
+ * Each TargetAddress belongs to a portal group, identified by its
+ * numeric Target Portal Group Tag. The iSCSI Target Name, together with
+ * this tag, constitutes the SCSI port identifier; the tag only needs to
+ * be unique within a given target's name list of addresses.\n
+ * Multiple-connection sessions can span iSCSI addresses that belong to
+ * the same portal group.\n
+ * Multiple-connection sessions cannot span iSCSI addresses that belong
+ * to different portal groups.\n
+ * If a SendTargets response reports an iSCSI address for a target, it
+ * SHOULD also report all other addresses in its portal group in the
+ * same response.\n
+ * A SendTargets Text Response can be longer than a single Text Response
+ * PDU and makes use of the long Text Responses as specified.\n
+ * After obtaining a list of targets from the Discovery session, an
+ * iSCSI initiator may initiate new sessions to log in to the discovered
+ * targets for full operation. The initiator MAY keep the Discovery
+ * session open and MAY send subsequent SendTargets commands to discover
+ * new targets.\n
+ * Examples:\n
+ * This example is the SendTargets response from a single target that
+ * has no other interface ports.\n
+ * The initiator sends a Text Request that contains:
+ * @verbatim
+ *    SendTargets=All
+ * @endverbatim
+ * The target sends a Text Response that contains:
+ * @verbatim
+ *    TargetName=iqn.1993-11.de.uni-freiburg:diskarray.sn.8675309
+ * @endverbatim
+ * All the target had to return in this simple case was the target name.\n
+ * It is assumed by the initiator that the IP address and TCP port for
+ * this target are the same as those used on the current connection to
+ * the default iSCSI target.\n
+ * The next example has two internal iSCSI targets, each accessible via
+ * two different ports with different IP addresses. The following is
+ * the Text Response:
+ * @verbatim
+ *    TargetName=iqn.1993-11.de.uni-freiburg:diskarray.sn.8675309
+ *    TargetAddress=10.1.0.45:5300,1
+ *    TargetAddress=10.1.1.45:5300,2
+ *    TargetName=iqn.1993-11.de.uni-freiburg:diskarray.sn.1234567
+ *    TargetAddress=10.1.0.45:5300,1
+ *    TargetAddress=10.1.1.45:5300,2
+ * @endverbatim
+ * Both targets share both addresses; the multiple addresses are likely
+ * used to provide multi-path support. The initiator may connect to
+ * either target name on either address. Each of the addresses has its
+ * own Target Portal Group Tag; they do not support spanning multiple-
+ * connection sessions with each other. Keep in mind that the Target
+ * Portal Group Tags for the two named targets are independent of one
+ * another; portal group "1" on the first target is not necessarily the
+ * same as portal group "1" on the second target.\n
+ * In the above example, a DNS host name or an IPv6 address could have
+ * been returned instead of an IPv4 address.\n
+ * The next Text Response shows a target that supports spanning sessions
+ * across multiple addresses and further illustrates the use of the
+ * Target Portal Group Tags:
+ * @verbatim
+ *    TargetName=iqn.1993-11.de.uni-freiburg:diskarray.sn.8675309
+ *    TargetAddress=10.1.0.45:5300,1
+ *    TargetAddress=10.1.1.46:5300,1
+ *    TargetAddress=10.1.0.47:5300,2
+ *    TargetAddress=10.1.1.48:5300,2
+ *    TargetAddress=10.1.1.49:5300,3
+ * @endverbatim
+ * In this example, any of the target addresses can be used to reach the
+ * same target. A single-connection session can be established to any
+ * of these TCP addresses. A multiple-connection session could span
+ * addresses .45 and .46 or .47 and .48 but cannot span any other
+ * combination. A TargetAddress with its own tag (.49) cannot be
+ * combined with any other address within the same session.\n
+ * This SendTargets response does not indicate whether .49 supports
+ * multiple connections per session; it is communicated via the
+ * MaxConnections text key upon login to the target.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_SEND_TARGETS "SendTargets"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Initial Ready To Transfer.
+ *
+ * @verbatim
+ * Use: LO
+ * Senders: Initiator and target
+ * Scope: SW
+ * Irrelevant when: SessionType=Discovery
+ * InitialR2T=<boolean-value>
+ * Examples:
+ *    I->InitialR2T=No
+ *    T->InitialR2T=No
+ * Default is Yes.
+ * @endverbatim
+ * Result function is OR.\n
+ * The InitialR2T key is used to turn off the default use of R2T for
+ * unidirectional operations and the output part of bidirectional
+ * commands, thus allowing an initiator to start sending data to a
+ * target as if it has received an initial R2T with Buffer
+ * Offset=Immediate Data Length and Desired Data Transfer
+ * Length=(min(FirstBurstLength, Expected Data Transfer Length) -
+ * Received Immediate Data Length).\n
+ * The default action is that R2T is required, unless both the initiator
+ * and the target send this key-pair attribute specifying InitialR2T=No.
+ * Only the first outgoing data burst (immediate data and/or separate
+ * PDUs) can be sent unsolicited (i.e., not requiring an explicit R2T).
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_INITIAL_R2T "InitialR2T"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Immediate data.
+ *
+ * @verbatim
+ * Use: LO
+ * Senders: Initiator and target
+ * Scope: SW
+ * Irrelevant when: SessionType=Discovery
+ * ImmediateData=<boolean-value>
+ * Default is Yes.
+ * @endverbatim
+ * Result function is AND.\n
+ * The initiator and target negotiate support for immediate dataTo
+ * turn immediate data off, the initiator or target must state its
+ * desire to do soImmediateData can be turned on if both the
+ * initiator and target have ImmediateData=Yes.\n
+ * If ImmediateData is set to Yes and InitialR2T is set to Yes
+ * (default), then only immediate data are accepted in the first burst.
+ * If ImmediateData is set to No and InitialR2T is set to Yes, then the
+ * initiator MUST NOT send unsolicited data and the target MUST reject
+ * unsolicited data with the corresponding response code.\n
+ * If ImmediateData is set to No and InitialR2T is set to No, then the
+ * initiator MUST NOT send unsolicited immediate data but MAY send one
+ * unsolicited burst of Data-OUT PDUs.\n
+ * If ImmediateData is set to Yes and InitialR2T is set to No, then the
+ * initiator MAY send unsolicited immediate data and/or one unsolicited
+ * burst of Data-OUT PDUs.\n
+ * The following table is a summary of unsolicited data options:
+ * InitialR2T | ImmediateData | Unsolicited Data-Out PDUs | ImmediateData
+ * :--------- | :------------ | :------------------------ | :------------
+ * | No       | No            | Yes                       | No          |
+ * | No       | Yes           | Yes                       | Yes         |
+ * | Yes      | No            | No                        | No          |
+ * | Yes      | Yes           | No                        | Yes         |
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_IMMEDIATE_DATA "ImmediateData"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Maximum receive DataSegmentLength.
+ *
+ * @verbatim
+ * Use: ALL, Declarative
+ * Senders: Initiator and target
+ * Scope: CO
+ * MaxRecvDataSegmentLength=<numerical-value-512-to-(2**24 - 1)>
+ * Default is 8192 bytes.
+ * @endverbatim
+ * The initiator or target declares the maximum data segment length in
+ * bytes it can receive in an iSCSI PDU.\n
+ * The transmitter (initiator or target) is required to send PDUs with a
+ * data segment that does not exceed MaxRecvDataSegmentLength of the
+ * receiver.\n
+ * A target receiver is additionally limited by MaxBurstLength for
+ * solicited data and FirstBurstLength for unsolicited dataAn
+ * initiator MUST NOT send solicited PDUs exceeding MaxBurstLength nor
+ * unsolicited PDUs exceeding FirstBurstLength (or FirstBurstLength-
+ * Immediate Data Length if immediate data were sent).
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_MAX_RECV_DS_LEN "MaxRecvDataSegmentLength"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Maximum burst length.
+ *
+ * @verbatim
+ * Use: LO
+ * Senders: Initiator and target
+ * Scope: SW
+ * Irrelevant when: SessionType=Discovery
+ * MaxBurstLength=<numerical-value-512-to-(2**24 - 1)>
+ * Default is 262144 (256 KB).
+ * @endverbatim
+ * Result function is Minimum.\n
+ * The initiator and target negotiate the maximum SCSI data payload in
+ * bytes in a Data-In or a solicited Data-Out iSCSI sequence. A
+ * sequence consists of one or more consecutive Data-In or Data-Out PDUs
+ * that end with a Data-In or Data-Out PDU with the F bit set to 1.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_MAX_BURST_LEN "MaxBurstLength"
+
+/**
+ * @brief Login/Text Operational Session Text Key: First burst length.
+ *
+ * @verbatim
+ * Use: LO
+ * Senders: Initiator and target
+ * Scope: SW
+ * Irrelevant when: SessionType=Discovery
+ * Irrelevant when: ( InitialR2T=Yes and ImmediateData=No )
+ * FirstBurstLength=<numerical-value-512-to-(2**24 - 1)>
+ * Default is 65536 (64 KB).
+ * @endverbatim
+ * Result function is Minimum.\n
+ * The initiator and target negotiate the maximum amount in bytes of
+ * unsolicited data an iSCSI initiator may send to the target during the
+ * execution of a single SCSI command. This covers the immediate data
+ * (if any) and the sequence of unsolicited Data-Out PDUs (if any) that
+ * follow the command.\n
+ * FirstBurstLength MUST NOT exceed MaxBurstLength.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_FIRST_BURST_LEN "FirstBurstLength"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Default time to wait.
+ *
+ * @verbatim
+ * Use: LO
+ * Senders: Initiator and target
+ * Scope: SW
+ * DefaultTime2Wait=<numerical-value-0-to-3600>
+ * Default is 2.
+ * @endverbatim
+ * Result function is Maximum.\n
+ * The initiator and target negotiate the minimum time, in seconds, to
+ * wait before attempting an explicit/implicit logout or an active task
+ * reassignment after an unexpected connection termination or a
+ * connection reset.\n
+ * A value of 0 indicates that logout or active task reassignment can be
+ * attempted immediately.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_DEFAULT_TIME_WAIT "DefaultTime2Wait"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Default time to retain.
+ *
+ * @verbatim
+ * Use: LO
+ * Senders: Initiator and target
+ * Scope: SW
+ * DefaultTime2Retain=<numerical-value-0-to-3600>
+ * Default is 20.
+ * @endverbatim
+ * Result function is Minimum.\n
+ * The initiator and target negotiate the maximum time, in seconds,
+ * after an initial wait (Time2Wait), before which an active task
+ * reassignment is still possible after an unexpected connection
+ * termination or a connection reset.\n
+ * This value is also the session state timeout if the connection in
+ * question is the last LOGGED_IN connection in the session.\n
+ * A value of 0 indicates that connection/task state is immediately
+ * discarded by the target.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_DEFAULT_TIME_RETAIN "DefaultTime2Retain"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Maximum outstanding Ready To Transfer.
+ *
+ * @verbatim
+ * Use: LO
+ * Senders: Initiator and target
+ * Scope: SW
+ * MaxOutstandingR2T=<numerical-value-from-1-to-65535>
+ * Irrelevant when: SessionType=Discovery
+ * Default is 1.
+ * @endverbatim
+ * Result function is Minimum.\n
+ * The initiator and target negotiate the maximum number of outstanding
+ * R2Ts per task, excluding any implied initial R2T that might be part
+ * of that task. An R2T is considered outstanding until the last data
+ * PDU (with the F bit set to 1) is transferred or a sequence reception
+ * timeout is encountered for that data sequence.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_MAX_OUTSTANDING_R2T "MaxOutstandingR2T"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Data Protocol Data Unit (PDU) in order.
+ *
+ * @verbatim
+ * Use: LO
+ * Senders: Initiator and target
+ * Scope: SW
+ * Irrelevant when: SessionType=Discovery
+ * DataPDUInOrder=<boolean-value>
+ * Default is Yes.
+ * @endverbatim
+ * Result function is OR.\n
+ * "No" is used by iSCSI to indicate that the data PDUs within sequences
+ * can be in any order. "Yes" is used to indicate that data PDUs within
+ * sequences have to be at continuously increasing addresses and
+ * overlays are forbidden.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_DATA_PDU_IN_ORDER "DataPDUInOrder"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Data sequence in order.
+ *
+ * @verbatim
+ * Use: LO
+ * Senders: Initiator and target
+ * Scope: SW
+ * Irrelevant when: SessionType=Discovery
+ * DataSequenceInOrder=<boolean-value>
+ * Default is Yes.
+ * @endverbatim
+ * Result function is OR.\n
+ * A data sequence is a sequence of Data-In or Data-Out PDUs that end
+ * with a Data-In or Data-Out PDU with the F bit set to 1. A Data-Out
+ * sequence is sent either unsolicited or in response to an R2T.\n
+ * Sequences cover an offset-range.\n
+ * If DataSequenceInOrder is set to No, data PDU sequences may be
+ * transferred in any order.\n
+ * If DataSequenceInOrder is set to Yes, data sequences MUST be
+ * transferred using continuously non-decreasing sequence offsets (R2T
+ * buffer offset for writes, or the smallest SCSI Data-In buffer offset
+ * within a read data sequence).\n
+ * If DataSequenceInOrder is set to Yes, a target may retry at most the
+ * last R2T, and an initiator may at most request retransmission for the
+ * last read data sequence. For this reason, if ErrorRecoveryLevel is
+ * not 0 and DataSequenceInOrder is set to Yes, then MaxOutstandingR2T
+ * MUST be set to 1.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_DATA_SEQ_IN_ORDER "DataSequenceInOrder"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Error recovery level.
+ *
+ * @verbatim
+ * Use: LO
+ * Senders: Initiator and target
+ * Scope: SW
+ * ErrorRecoveryLevel=<numerical-value-0-to-2>
+ * Default is 0.
+ * @endverbatim
+ * Result function is Minimum.\n
+ * The initiator and target negotiate the recovery level supported.
+ * Recovery levels represent a combination of recovery capabilities.
+ * Each recovery level includes all the capabilities of the lower
+ * recovery levels and adds some new ones to them.\n
+ * In the description of recovery mechanisms, certain recovery classes
+ * are specified.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_ERR_RECOVERY_LEVEL "ErrorRecoveryLevel"
+
+/**
+ * @brief Login/Text Operational Session Text Key: X reversed vendor.
+ *
+ * @verbatim
+ * Use: ALL
+ * Senders: Initiator and target
+ * Scope: specific key dependent
+ * X-reversed.vendor.dns_name.do_something=
+ * @endverbatim
+ * Keys with this format are used for private extension purposes. These
+ * keys always start with X- if unregistered with IANA (private). New
+ * public keys (if registered with IANA via an IETF Review RFC5226) no
+ * longer have an X# name prefix requirement; implementers may propose
+ * any intuitive unique name.\n
+ * For unregistered keys, to identify the vendor we suggest using the
+ * reversed DNS-name as a prefix to the key-proper.\n
+ * The part of key-name following X- MUST conform to the format for
+ * key-name.\n
+ * Vendor-specific keys MUST ONLY be used in Normal sessions.\n
+ * Support for public or private extension keys is OPTIONAL.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_PRIV_EXT_KEY_FMT "X-reversed.vendor"
+
+/**
+ * @brief Login/Text Operational Session Text Key: Task reporting.
+ *
+ * @verbatim
+ * Use: LO
+ * Senders: Initiator and target
+ * Scope: SW
+ * Irrelevant when: SessionType=Discovery
+ * TaskReporting=<list-of-values>
+ * Default is RFC3720.
+ * @endverbatim
+ * This key is used to negotiate the task completion reporting semantics
+ * from the SCSI target. The following table describes the semantics
+ * that an iSCSI target MUST support for respective negotiated key
+ * values. Whenever this key is negotiated, at least the RFC3720 and
+ * ResponseFence values MUST be offered as options by the negotiation
+ * originator.
+ * Name            | Description
+ * :-------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------
+ * | RFC3720       | RFC 3720-compliant semantics. Response fencing is not guaranteed, and fast completion of multi-task aborting is not supported.
+ * | ResponseFence | Response Fence semantics MUST be supported in reporting task completions.
+ * | FastAbort     | Updated fast multi-task abort semantics defined in MUST be supported. Support for the Response. Fence is implied - i.e., semantics MUST be supported as well.
+ *
+ * When TaskReporting is not negotiated to FastAbort, the
+ * standard multi-task abort semantics MUST be used.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_TASK_REPORTING "TaskReporting"
+
+/**
+ * @brief Login/Text Operational Session Text Key: X Node architecture.
+ *
+ * @verbatim
+ * Use: LO, Declarative
+ * Senders: Initiator and target
+ * Scope: SW
+ * X#NodeArchitecture=<list-of-values>
+ * Default is None.
+ * Examples:
+ *    X#NodeArchitecture=ExampleOS/v1234,ExampleInc_SW_Initiator/1.05a
+ *    X#NodeArchitecture=ExampleInc_HW_Initiator/4010,Firmware/2.0.0.5
+ *    X#NodeArchitecture=ExampleInc_SW_Initiator/2.1,CPU_Arch/i686
+ * @endverbatim
+ * This document does not define the structure or content of the list of
+ * values.\n
+ * The initiator or target declares the details of its iSCSI node
+ * architecture to the remote endpoint. These details may include, but
+ * are not limited to, iSCSI vendor software, firmware, or hardware
+ * versions; the OS version; or hardware architecture. This key may be
+ * declared on a Discovery session or a Normal session.\n
+ * The length of the key value (total length of the list-of-values) MUST
+ * NOT be greater than 255 bytes.\n
+ * X#NodeArchitecture MUST NOT be redeclared during the Login Phase.\n
+ * Functional behavior of the iSCSI node (this includes the iSCSI
+ * protocol logic - the SCSI, iSCSI, and TCP/IP protocols) MUST NOT
+ * depend on the presence, absence, or content of the X#NodeArchitecture
+ * key. The key MUST NOT be used by iSCSI nodes for interoperability or
+ * for exclusion of other nodes. To ensure proper use, key values
+ * SHOULD be set by the node itself, and there SHOULD NOT be provisions
+ * for the key values to contain user-defined text.\n
+ * Nodes implementing this key MUST choose one of the following
+ * implementation options:\n
+ * - only transmit the key,
+ * - only log the key values received from other nodes, or
+ * - both transmit and log the key values.
+ *
+ * Each node choosing to implement transmission of the key values MUST
+ * be prepared to handle the response of iSCSI nodes that do not
+ * understand the key.\n
+ * Nodes that implement transmission and/or logging of the key values
+ * may also implement administrative mechanisms that disable and/or
+ * change the logging and key transmission details.\n
+ * Thus, a valid behavior for this key may be that a node is completely
+ * silent (the node does not transmit any key value and simply discards
+ * any key values it receives without issuing a NotUnderstood response).
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_X_NODE_ARCH "X#NodeArchitecture"
+
+/**
+ * @brief Login/Text Operational Session Text Key: IFMarker (obseleted).
+ *
+ * This document obsoletes the following keys defined in RFC3720:\n
+ * IFMarker, OFMarker, OFMarkInt, and IFMarkInt. However, iSCSI
+ * mplementations compliant to this document may still receive these
+ * obsoleted keys - i.e., in a responder role - in a text negotiation.\n
+ * When an IFMarker or OFMarker key is received, a compliant iSCSI
+ * implementation SHOULD respond with the constant "Reject" value. The
+ * implementation MAY alternatively respond with a "No" value.\n
+ * However, the implementation MUST NOT respond with a "NotUnderstood"
+ * value for either of these keys.\n
+ * When an IFMarkInt or OFMarkInt key is received, a compliant iSCSI
+ * implementation MUST respond with the constant "Reject" value. The
+ * implementation MUST NOT respond with a "NotUnderstood" value for
+ * either of these keys.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_IF_MARKER   "IFMarker"
+
+/**
+ * @brief Login/Text Operational Session Text Key: OFMarker (obseleted).
+ *
+ * This document obsoletes the following keys defined in RFC3720:\n
+ * IFMarker, OFMarker, OFMarkInt, and IFMarkInt. However, iSCSI
+ * mplementations compliant to this document may still receive these
+ * obsoleted keys - i.e., in a responder role - in a text negotiation.\n
+ * When an IFMarker or OFMarker key is received, a compliant iSCSI
+ * implementation SHOULD respond with the constant "Reject" value. The
+ * implementation MAY alternatively respond with a "No" value.\n
+ * However, the implementation MUST NOT respond with a "NotUnderstood"
+ * value for either of these keys.\n
+ * When an IFMarkInt or OFMarkInt key is received, a compliant iSCSI
+ * implementation MUST respond with the constant "Reject" value. The
+ * implementation MUST NOT respond with a "NotUnderstood" value for
+ * either of these keys.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_OF_MARKER   "OFMarker"
+
+/**
+ * @brief Login/Text Operational Session Text Key: OFMarkInt (obseleted).
+ *
+ * This document obsoletes the following keys defined in RFC3720:\n
+ * IFMarker, OFMarker, OFMarkInt, and IFMarkInt. However, iSCSI
+ * mplementations compliant to this document may still receive these
+ * obsoleted keys - i.e., in a responder role - in a text negotiation.\n
+ * When an IFMarker or OFMarker key is received, a compliant iSCSI
+ * implementation SHOULD respond with the constant "Reject" value. The
+ * implementation MAY alternatively respond with a "No" value.\n
+ * However, the implementation MUST NOT respond with a "NotUnderstood"
+ * value for either of these keys.\n
+ * When an IFMarkInt or OFMarkInt key is received, a compliant iSCSI
+ * implementation MUST respond with the constant "Reject" value. The
+ * implementation MUST NOT respond with a "NotUnderstood" value for
+ * either of these keys.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_OF_MARK_INT "OFMarkInt"
+
+/**
+ * @brief Login/Text Operational Session Text Key: IFMarkInt (obseleted).
+ *
+ * This document obsoletes the following keys defined in RFC3720:\n
+ * IFMarker, OFMarker, OFMarkInt, and IFMarkInt. However, iSCSI
+ * mplementations compliant to this document may still receive these
+ * obsoleted keys - i.e., in a responder role - in a text negotiation.\n
+ * When an IFMarker or OFMarker key is received, a compliant iSCSI
+ * implementation SHOULD respond with the constant "Reject" value. The
+ * implementation MAY alternatively respond with a "No" value.\n
+ * However, the implementation MUST NOT respond with a "NotUnderstood"
+ * value for either of these keys.\n
+ * When an IFMarkInt or OFMarkInt key is received, a compliant iSCSI
+ * implementation MUST respond with the constant "Reject" value. The
+ * implementation MUST NOT respond with a "NotUnderstood" value for
+ * either of these keys.
+ */
+#define ISCSI_LOGIN_AUTH_SESSION_TEXT_KEY_IF_MARK_INT "IFMarkInt"
+
+
+/// Login request flags: SecurityNegotiation.
+#define ISCSI_LOGIN_REQ_FLAGS_NEXT_STAGE_SECURITY_NEGOTIATION          0x0
+
+/// Login request flags: LoginOperationalNegotiation.
+#define ISCSI_LOGIN_REQ_FLAGS_NEXT_STAGE_LOGIN_OPERATIONAL_NEGOTIATION 0x1
+
+/// Login request flags: FullFeaturePhase.
+#define ISCSI_LOGIN_REQ_FLAGS_NEXT_STAGE_FULL_FEATURE_PHASE            0x3
+
+/**
+ * @brief Login request flags: Next Stage (NSG): First bit of the two bits.
+ *
+ * The Login negotiation requests and responses are associated
+ * with a specific stage in the session (SecurityNegotiation,\n
+ * LoginOperationalNegotiation, FullFeaturePhase) and may indicate the
+ * next stage to which they want to move. The Next Stage value is only
+ * valid when the T bit is 1; otherwise, it is reserved.
+ */
+#define ISCSI_LOGIN_REQ_FLAGS_NEXT_STAGE    (1 << 0)
+
+/// Login request flags: Extracts the Next Stage (NSG) bits.
 #define ISCSI_LOGIN_REQS_FLAGS_GET_NEXT_STAGE(x) ((x) & 3)
 
-#define ISCSI_LOGIN_REQ_FLAGS_CURRENT_STAGE_SECURITY_NEGOTIATION          0x0 // SecurityNegotiation
-#define ISCSI_LOGIN_REQ_FLAGS_CURRENT_STAGE_LOGIN_OPERATIONAL_NEGOTIATION 0x1 // LoginOperationalNegotiation
-#define ISCSI_LOGIN_REQ_FLAGS_CURRENT_STAGE_FULL_FEATURE_PHASE            0x3 // FullFeaturePhase
-#define ISCSI_LOGIN_REQ_FLAGS_CURRENT_STAGE (1 << 2) // (CSG) - Two bits - the Login negotiation requests and responses are
-                                                     // associated with aspecific stage in the session (SecurityNegotiation,
-                                                     // LoginOperationalNegotiation, FullFeaturePhase) and may indicate the
-                                                     // next stage to which they want to move
+
+/// Login request flags: SecurityNegotiation.
+#define ISCSI_LOGIN_REQ_FLAGS_CURRENT_STAGE_SECURITY_NEGOTIATION          0x0
+
+/// Login request flags: LoginOperationalNegotiation.
+#define ISCSI_LOGIN_REQ_FLAGS_CURRENT_STAGE_LOGIN_OPERATIONAL_NEGOTIATION 0x1
+
+/// Login request flags: FullFeaturePhase.
+#define ISCSI_LOGIN_REQ_FLAGS_CURRENT_STAGE_FULL_FEATURE_PHASE            0x3
+
+/**
+ * @brief Login request flags: Current Stage (CSG): First bit of the two bits.
+ *
+ * The Login negotiation requests and responses are associated
+ * with aspecific stage in the session (SecurityNegotiation,
+ * LoginOperationalNegotiation, FullFeaturePhase) and may indicate the
+ * next stage to which they want to move.
+ */
+#define ISCSI_LOGIN_REQ_FLAGS_CURRENT_STAGE (1 << 2)
+
+/// Login request flags: Extracts the Current Stage (CSG) bits.
 #define ISCSI_LOGIN_REQS_FLAGS_GET_CURRENT_STAGE(x) (((x) >> 2) & 3)
 
-#define ISCSI_LOGIN_REQ_FLAGS_CONTINUE      (1 << 6) // (C) When set to 1, this bit indicates that the text (set of key=value
-                                                     // pairs) in this Login Request is not complete (it will be continued on
-                                                     // subsequent Login Requests); otherwise, it indicates that this Login
-                                                     // Request ends a set of key=value pairs. A Login Request with the
-                                                     // C bit set to 1 MUST have the T bit set to 0.
-#define ISCSI_LOGIN_REQ_FLAGS_TRANSMIT      (1 << 7) // (T) When set to 1, this bit indicates that the initiator is ready to
-                                                     // transit to the next stage.
-                                                     // If the T bit is set to 1 and the NSG is set to FullFeaturePhase, then
-                                                     // this also indicates that the initiator is ready for the Login
-                                                     // Final-Response.
-
-/* After establishing a TCP connection between an initiator and a
-   target, the initiator MUST start a Login Phase to gain further access
-   to the target's resources.
-
-   The Login Phase consists of a sequence of Login Requests and Login
-   Responses that carry the same Initiator Task Tag.
-
-   Login Requests are always considered as immediate.
-*/
+
+/**
+ * @brief Login request flags: Continue.
+ *
+ * (C) When set to 1, this bit indicates that the text (set of key=value
+ * pairs) in this Login Request is not complete (it will be continued on
+ * subsequent Login Requests); otherwise, it indicates that this Login
+ * Request ends a set of key=value pairs. A Login Request with the
+ * C bit set to 1 MUST have the T bit set to 0.
+ */
+#define ISCSI_LOGIN_REQ_FLAGS_CONTINUE (1 << 6)
+
+/**
+ * @brief Login request flags: Transmit.
+ *
+ * (T) When set to 1, this bit indicates that the initiator is ready to
+ * transit to the next stage.\n
+ * If the T bit is set to 1 and the NSG is set to FullFeaturePhase, then
+ * this also indicates that the initiator is ready for the Login
+ * Final-Response.
+ */
+#define ISCSI_LOGIN_REQ_FLAGS_TRANSMIT (1 << 7)
+
+
+/**
+ * @brief iSCSI Login Request packet data.
+ *
+ * After establishing a TCP connection between an initiator and a
+ * target, the initiator MUST start a Login Phase to gain further access
+ * to the target's resources.
+ *
+ * The Login Phase consists of a sequence of Login Requests and Login
+ * Responses that carry the same Initiator Task Tag.
+ *
+ * Login Requests are always considered as immediate.
+ */
 typedef struct __attribute__((packed)) iscsi_login_req_packet {
-    uint8_t opcode; // Always 0x03 according to specification (see above)
-    int8_t flags; // Login request flags (see above)
-    uint8_t version_max; // Version-max indicates the maximum version number supported.
-                         // All Login Requests within the Login Phase MUST carry the same
-                         // Version-max. Currently, this is always 0
-                         // The target MUST use the value presented with the first Login Request.
-    uint8_t version_min; // All Login Requests within the Login Phase MUST carry the same
-                         // Version-min. The target MUST use the value presented with the first
-                         // Login Request. Always 0 for now
-    uint8_t total_ahs_len; // TotalAHSLength
-    uint8_t ds_len[3]; // DataSegmentLength
-    struct iscsi_isid isid; // ISID (see above for declaration)
-    uint16_t tsih; // The TSIH must be set in the first Login Request. The reserved value
-                   // 0 MUST be used on the first connection for a new session. Otherwise,
-                   // the TSIH sent by the target at the conclusion of the successful login
-                   // of the first connection for this session MUST be used. The TSIH
-                   // identifies to the target the associated existing session for this new
-                   // connection.
-                   // All Login Requests within a Login Phase MUST carry the same TSIH.
-                   // The target MUST check the value presented with the first Login
-                   // Request
-    uint32_t init_task_tag; // Initiator task tag
-    uint16_t cid; // Connection ID. The CID provides a unique ID for this connection within the session.
-                  // All Login Requests within the Login Phase MUST carry the same CID.
-                  // The target MUST use the value presented with the first Login Request.
-                  // A Login Request with a non-zero TSIH and a CID equal to that of an
-                  // existing connection implies a logout of the connection followed by a
-                  // login
-    uint16_t reserved; // Reserved for future usage
-    uint32_t cmd_sn; // The CmdSN is either the initial command sequence number of a session
-                     // (for the first Login Request of a session - the "leading" login) or
-                     // the command sequence number in the command stream if the login is for
-                     // a new connection in an existing session.
-                     // Examples:
-                     // - Login on a leading connection: If the leading login carries the
-                     //   CmdSN 123, all other Login Requests in the same Login Phase carry
-                     //   the CmdSN 123, and the first non-immediate command in the Full
-                     //   Feature Phase also carries the CmdSN 123.
-                     // - Login on other than a leading connection: If the current CmdSN at
-                     //   the time the first login on the connection is issued is 500, then
-                     //   that PDU carries CmdSN=500. Subsequent Login Requests that are
-                     //   needed to complete this Login Phase may carry a CmdSN higher than
-                     //   500 if non-immediate requests that were issued on other connections
-                     //   in the same session advance the CmdSN.
-                     // If the Login Request is a leading Login Request, the target MUST use
-                     // the value presented in the CmdSN as the target value for the
-                     // ExpCmdSN
-    uint32_t exp_stat_sn; // For the first Login Request on a connection, this is the ExpStatSN
-                          // for the old connection, and this field is only valid if the Login
-                          // Request restarts a connection
-                          // For subsequent Login Requests, it is used to acknowledge the Login
-                          // Responses with their increasing StatSN values
-    uint64_t reserved2[2]; // Reserved for future usage
-    struct iscsi_ds_cmd_data ds_cmd_data; // Data segment - Login Parameters in Text Request Format
-                                          // The initiator MUST provide some basic parameters in order
-                                          // to enable the target to determine if the initiator may use
-                                          // the target's resources and the initial text parameters for the security exchange
+    /// Always 0x03 according to iSCSI specification.
+    uint8_t opcode;
+
+    /// Login request flags.
+    int8_t flags;
+
+    /**
+     * @brief Version-max indicates the maximum version number supported.
+     *
+     * All Login Requests within the Login Phase MUST carry the same
+     * Version-max. Currently, this is always 0.\n
+     * The target MUST use the value presented with the first Login Request.
+     */
+    uint8_t version_max;
+
+    /**
+     * @brief Version-min indicates the minimum version number supported.
+     *
+     * All Login Requests within the Login Phase MUST carry the same
+     * Version-min. The target MUST use the value presented with the first
+     * Login Request. Always 0 for now.
+     */
+    uint8_t version_min;
+
+    /// TotalAHSLength.
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength.
+    uint8_t ds_len[3];
+
+    /// Initiator Session ID (ISID).
+    iscsi_isid isid;
+
+    /**
+     * @brief Target Session Identifying Handle (TSIH).
+     *
+     * The TSIH must be set in the first Login Request. The reserved value
+     * 0 MUST be used on the first connection for a new session. Otherwise,
+     * the TSIH sent by the target at the conclusion of the successful login
+     * of the first connection for this session MUST be used. The TSIH
+     * identifies to the target the associated existing session for this new
+     * connection.\n
+     * All Login Requests within a Login Phase MUST carry the same TSIH.
+     * The target MUST check the value presented with the first Login
+     * Request.
+     */
+    uint16_t tsih;
+
+    /// Initiator Task Tag (ITT).
+    uint32_t init_task_tag;
+
+    /**
+     * @brief Connection ID (CID).
+     *
+     * The CID provides a unique ID for this connection within the session.\n
+     * All Login Requests within the Login Phase MUST carry the same CID.
+     * The target MUST use the value presented with the first Login Request.\n
+     * A Login Request with a non-zero TSIH and a CID equal to that of an
+     * existing connection implies a logout of the connection followed by a
+     * login.
+     */
+    uint16_t cid;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint16_t reserved;
+
+    /**
+     * @brief CmdSN.
+     *
+     * The CmdSN is either the initial command sequence number of a session
+     * (for the first Login Request of a session - the "leading" login) or
+     * the command sequence number in the command stream if the login is for
+     * a new connection in an existing session.\n
+     * Examples:
+     * - Login on a leading connection: If the leading login carries the
+     *   CmdSN 123, all other Login Requests in the same Login Phase carry
+     *   the CmdSN 123, and the first non-immediate command in the Full
+     *   Feature Phase also carries the CmdSN 123.
+     * - Login on other than a leading connection: If the current CmdSN at
+     *   the time the first login on the connection is issued is 500, then
+     *   that PDU carries CmdSN=500. Subsequent Login Requests that are
+     *   needed to complete this Login Phase may carry a CmdSN higher than
+     *   500 if non-immediate requests that were issued on other connections
+     *   in the same session advance the CmdSN.
+     *
+     * If the Login Request is a leading Login Request, the target MUST use
+     * the value presented in the CmdSN as the target value for the
+     * ExpCmdSN.
+     */
+    uint32_t cmd_sn;
+
+    /**
+     * @brief ExpStatSN.
+     *
+     * For the first Login Request on a connection, this is the ExpStatSN
+     * for the old connection, and this field is only valid if the Login
+     * Request restarts a connection.\n
+     * For subsequent Login Requests, it is used to acknowledge the Login
+     * Responses with their increasing StatSN values.
+     */
+    uint32_t exp_stat_sn;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint64_t reserved2[2];
+
+    /**
+     * @brief Data segment - Login Parameters in Text Request Format.
+     *
+     * The initiator MUST provide some basic parameters in order
+     * to enable the target to determine if the initiator may use
+     * the target's resources and the initial text parameters for the security exchange
+     */
+    iscsi_ds_cmd_data ds_cmd_data;
 } iscsi_login_req_packet;
 
-#define ISCSI_LOGIN_RESPONSE_FLAGS_NEXT_STAGE_SECURITY_NEGOTIATION          0x0 // SecurityNegotiation
-#define ISCSI_LOGIN_RESPONSE_FLAGS_NEXT_STAGE_LOGIN_OPERATIONAL_NEGOTIATION 0x1 // LoginOperationalNegotiation
-#define ISCSI_LOGIN_RESPONSE_FLAGS_NEXT_STAGE_FULL_FEATURE_PHASE            0x3 // FullFeaturePhase
-#define ISCSI_LOGIN_RESPONSE_FLAGS_NEXT_STAGE    (1 << 0) // (NSG) - Two bits - the Login negotiation requests and responses are
-                                                          // associated with a specific stage in the session (SecurityNegotiation,
-                                                          // LoginOperationalNegotiation, FullFeaturePhase) and may indicate the
-                                                          // next stage to which they want to move The Next Stage value is only
-                                                          // valid when the T bit is 1; otherwise, it is reserved
+
+/// Login response flags: SecurityNegotiation.
+#define ISCSI_LOGIN_RESPONSE_FLAGS_NEXT_STAGE_SECURITY_NEGOTIATION          0x0
+
+/// Login response flags: LoginOperationalNegotiation.
+#define ISCSI_LOGIN_RESPONSE_FLAGS_NEXT_STAGE_LOGIN_OPERATIONAL_NEGOTIATION 0x1
+
+/// Login response flags: FullFeaturePhase.
+#define ISCSI_LOGIN_RESPONSE_FLAGS_NEXT_STAGE_FULL_FEATURE_PHASE            0x3
+
+/**
+ * @brief Login response flags: Next Stage (NSG): First bit of the two bits.
+ *
+ * The Login negotiation requests and responses are associated
+ * with a specific stage in the session (SecurityNegotiation,
+ * LoginOperationalNegotiation, FullFeaturePhase) and may indicate the
+ * next stage to which they want to move The Next Stage value is only
+ * valid when the T bit is 1; otherwise, it is reserved.
+ */
+#define ISCSI_LOGIN_RESPONSE_FLAGS_NEXT_STAGE    (1 << 0)
+
+/// Login response flags: Extracts the Next Stage (NSG) bits.
 #define ISCSI_LOGIN_RESPONSE_FLAGS_GET_NEXT_STAGE(x) ((x) & 3)
 
-#define ISCSI_LOGIN_RESPONSE_FLAGS_CURRENT_STAGE_SECURITY_NEGOTIATION          0x0 // SecurityNegotiation
-#define ISCSI_LOGIN_RESPONSE_FLAGS_CURRENT_STAGE_LOGIN_OPERATIONAL_NEGOTIATION 0x1 // LoginOperationalNegotiation
-#define ISCSI_LOGIN_RESPONSE_FLAGS_CURRENT_STAGE_FULL_FEATURE_PHASE            0x3 // FullFeaturePhase
-#define ISCSI_LOGIN_RESPONSE_FLAGS_CURRENT_STAGE (1 << 2) // (CSG) - Two bits - the Login negotiation requests and responses are
-                                                          // associated with aspecific stage in the session (SecurityNegotiation,
-                                                          // LoginOperationalNegotiation, FullFeaturePhase) and may indicate the
-                                                          // next stage to which they want to move
+/// Login response flags: SecurityNegotiation.
+#define ISCSI_LOGIN_RESPONSE_FLAGS_CURRENT_STAGE_SECURITY_NEGOTIATION          0x0
+
+/// Login response flags: LoginOperationalNegotiation.
+#define ISCSI_LOGIN_RESPONSE_FLAGS_CURRENT_STAGE_LOGIN_OPERATIONAL_NEGOTIATION 0x1
+
+/// Login response flags: FullFeaturePhase.
+#define ISCSI_LOGIN_RESPONSE_FLAGS_CURRENT_STAGE_FULL_FEATURE_PHASE            0x3
+
+/**
+ * @brief Login response flags: Current Stage (CSG): First bit of the two bits.
+ *
+ * The Login negotiation requests and responses are associated
+ * with aspecific stage in the session (SecurityNegotiation,
+ * LoginOperationalNegotiation, FullFeaturePhase) and may indicate the
+ * next stage to which they want to move.
+ */
+#define ISCSI_LOGIN_RESPONSE_FLAGS_CURRENT_STAGE (1 << 2)
+
+/// Login response flags: Extracts the Current Stage (CSG) bits.
 #define ISCSI_LOGIN_RESPONSE_FLAGS_GET_CURRENT_STAGE(x) (((x) >> 2) & 3)
 
-#define ISCSI_LOGIN_RESPONSE_FLAGS_CONTINUE      (1 << 6) // (C) When set to 1, this bit indicates that the text (set of key=value
-                                                          // pairs) in this Login Response is not complete (it will be continued
-                                                          // on subsequent Login Responses); otherwise, it indicates that this
-                                                          // Login Response ends a set of key=value pairs. A Login Response with
-                                                          // the C bit set to 1 MUST have the T bit set to 0
-#define ISCSI_LOGIN_RESPONSE_FLAGS_TRANSMIT      (1 << 7) // (T) The T bit is set to 1 as an indicator of the end of the stage. If
-                                                          // the T bit is set to 1 and the NSG is set to FullFeaturePhase, then
-                                                          // this is also the Login Final-Response. A T bit of 0 indicates a
-                                                          // "partial" response, which means "more negotiation needed".
-                                                          // A Login Response with the T bit set to 1 MUST NOT contain key=value
-                                                          // pairs that may require additional answers from the initiator within
-                                                          // the same stage.
-                                                          // If the Status-Class is 0, the T bit MUST NOT be set to 1 if the T bit
-                                                          // in the request was set to 0
-
-#define ISCSI_LOGIN_RESPONSE_STATUS_CLASS_SUCCESS 0x00 // Success - indicates that the iSCSI target successfully
-                                                       // received, understood, and accepted the request. The numbering
-                                                       // fields (StatSN, ExpCmdSN, MaxCmdSN) are only valid if Status-
-                                                       // Class is 0
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_SUCCESS 0x00 // Login is proceeding OK. If the response T bit is set to 1 in both the
-                                                         // request and the matching response, and the NSG is set to
-                                                         // FullFeaturePhase in both the request and the matching response, the
-                                                         // Login Phase is finished, and the initiator may proceed to issue SCSI
-                                                         // commands.
-
-#define ISCSI_LOGIN_RESPONSE_STATUS_CLASS_REDIRECT 0x01 // Redirection - indicates that the initiator must take further
-                                                        // action to complete the request. This is usually due to the
-                                                        // target moving to a different address. All of the redirection
-                                                        // Status-Class responses MUST return one or more text key
-                                                        // parameters of the type "TargetAddress", which indicates the
-                                                        // target's new address. A redirection response MAY be issued by
-                                                        // a target prior to or after completing a security negotiation if
-                                                        // a security negotiation is required. A redirection SHOULD be
-                                                        // accepted by an initiator, even without having the target
-                                                        // complete a security negotiation if any security negotiation is
-                                                        // required, and MUST be accepted by the initiator after the
-                                                        // completion of the security negotiation if any security
-                                                        // negotiation is required
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_REDIRECT_TEMP 0x01 // The requested iSCSI Target Name (ITN) has temporarily moved
-                                                               // to the address provided
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_REDIRECT_PERM 0x02 // The requested ITN has permanently moved to the address provided
-
-#define ISCSI_LOGIN_RESPONSE_STATUS_CLASS_CLIENT_ERR 0x02 // Initiator Error (not a format error) - indicates that the
-                                                          // initiator most likely caused the error. This MAY be due to a
-                                                          // request for a resource for which the initiator does not have
-                                                          // permission. The request should not be tried again
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_MISC                   0x00 // Miscellaneous iSCSI initiator errors
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_AUTH_ERR               0x01 // The initiator could not be successfully
-                                                                                   // authenticated or target authentication is
-                                                                                   // not supported
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_AUTH_FAIL              0x02 // The initiator is not allowed access to the
-                                                                                   // given target
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_NOT_FOUND              0x03 // The requested ITN does not exist at this
-                                                                                   // address
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_TARGET_REMOVED         0x04 // The requested ITN has been removed, and
-                                                                                   // no forwarding address is provided
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_WRONG_VERSION          0x05 // The requested iSCSI version range is not
-                                                                                   // supported by the target
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_TOO_MANY_CONNECTIONS   0x06 // Too many connections on this SSID
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_MISSING_PARAMETER      0x07 // Missing parameters (e.g. iSCSI Initiator
-                                                                                   // Name and/or Target Name)
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_NO_SESSION_SPANNING    0x08 // arget does not support session spanning
-                                                                                   // to this connection (address)
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_SESSION_NO_SUPPORT     0x09 // Target does not support this type of
-                                                                                   // session or not from this initiator
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_SESSION_NO_EXIST       0x0A // Attempt to add a connection to a non-
-                                                                                   // existent session
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_INVALID_LOGIN_REQ_TYPE 0x0B // Invalid request type during login
-
-#define ISCSI_LOGIN_RESPONSE_STATUS_CLASS_SERVER_ERR 0x03 // Target Error - indicates that the target sees no errors in the
-                                                          // initiator's Login Request but is currently incapable of
-                                                          // fulfilling the request. The initiator may retry the same Login
-                                                          // Request later
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_SERVER_ERR_TARGET_ERROR        0x00 // Target hardware or software error
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_SERVER_ERR_SERVICE_UNAVAILABLE 0x01 // The iSCSI service or target is not
-                                                                                // currently operational
-#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_SERVER_ERR_OUT_OF_RESOURCES    0x02 // The target has insufficient session,
-                                                                                // connection, or other resources
-
-/* The Login Response indicates the progress and/or end of the Login
-   Phase.
-*/
+/**
+ * @brief Login response flags: Continue.
+ *
+ * (C) When set to 1, this bit indicates that the text (set of key=value
+ * pairs) in this Login Response is not complete (it will be continued
+ * on subsequent Login Responses); otherwise, it indicates that this
+ * Login Response ends a set of key=value pairs. A Login Response with
+ * the C bit set to 1 MUST have the T bit set to 0.
+ */
+#define ISCSI_LOGIN_RESPONSE_FLAGS_CONTINUE      (1 << 6)
+
+/**
+ * @brief Login response flags: Transmit.
+ *
+ * (T) The T bit is set to 1 as an indicator of the end of the stage. If
+ * the T bit is set to 1 and the NSG is set to FullFeaturePhase, then
+ * this is also the Login Final-Response. A T bit of 0 indicates a
+ * "partial" response, which means "more negotiation needed".\n
+ * A Login Response with the T bit set to 1 MUST NOT contain key=value
+ * pairs that may require additional answers from the initiator within
+ * the same stage.\n
+ * If the Status-Class is 0, the T bit MUST NOT be set to 1 if the T bit
+ * in the request was set to 0.
+ */
+#define ISCSI_LOGIN_RESPONSE_FLAGS_TRANSMIT      (1 << 7)
+
+
+/**
+ * @brief Login response status class: Success.
+ *
+ * Indicates that the iSCSI target successfully received, understood,
+ * and accepted the request. The numbering fields (StatSN, ExpCmdSN,
+ * MaxCmdSN) are only valid if Status-Class is 0.
+ */
+#define ISCSI_LOGIN_RESPONSE_STATUS_CLASS_SUCCESS 0x00
+
+/**
+ * @brief Login response status details: Success.
+ *
+ * Login is proceeding OK. If the response T bit is set to 1 in both the
+ * request and the matching response, and the NSG is set to
+ * FullFeaturePhase in both the request and the matching response, the
+ * Login Phase is finished, and the initiator may proceed to issue SCSI
+ * commands.
+ */
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_SUCCESS 0x00
+
+
+/**
+ * @brief Login response status class: Redirection.
+ *
+ * Indicates that the initiator must take further action
+ * to complete the request. This is usually due to the
+ * target moving to a different address. All of the redirection
+ * Status-Class responses MUST return one or more text key
+ * parameters of the type "TargetAddress", which indicates the
+ * target's new address. A redirection response MAY be issued by
+ * a target prior to or after completing a security negotiation if
+ * a security negotiation is required. A redirection SHOULD be
+ * accepted by an initiator, even without having the target
+ * complete a security negotiation if any security negotiation is
+ * required, and MUST be accepted by the initiator after the
+ * completion of the security negotiation if any security
+ * negotiation is required.
+ */
+#define ISCSI_LOGIN_RESPONSE_STATUS_CLASS_REDIRECT 0x01
+
+/**
+ * @brief Login response status details: Temporarily redirected.
+ *
+ * The requested iSCSI Target Name (ITN) has temporarily moved
+ * to the address provided.
+ */
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_REDIRECT_TEMP 0x01
+
+/**
+ * @brief Login response status details: Permanently redirected.
+ *
+ * The requested ITN has permanently moved to the address provided.
+ */
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_REDIRECT_PERM 0x02
+
+
+/**
+ * @brief Login response status class: Initiator Error (not a format error).
+ *
+ * Indicates that the initiator most likely caused the error.\n
+ * This MAY be due to a request for a resource for which the
+ * initiator does not have permission. The request should
+ * not be tried again.
+ */
+#define ISCSI_LOGIN_RESPONSE_STATUS_CLASS_CLIENT_ERR 0x02
+
+/// Login response status details: Miscellaneous iSCSI initiator errors.
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_MISC                   0x00
+
+/// Login response status details: The initiator could not be successfully authenticated or target authentication is not supported.
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_AUTH_ERR               0x01
+
+/// Login response status details: The initiator is not allowed access to the given target.
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_AUTH_FAIL              0x02
+
+/// Login response status details: The requested iSCSI Target Name (ITN) does not exist at this address.
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_NOT_FOUND              0x03
+
+/// Login response status details: The requested ITN has been removed, and no forwarding address is provided.
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_TARGET_REMOVED         0x04
+
+/// Login response status details: The requested iSCSI version range is not supported by the target.
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_WRONG_VERSION          0x05
+
+/// Login response status details: Too many connections on this Session ID (SSID).
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_TOO_MANY_CONNECTIONS   0x06
+
+/// Login response status details: Missing parameters (e.g. iSCSI Initiator Name and/or Target Name).
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_MISSING_PARAMETER      0x07
+
+/// Login response status details: Target does not support session spanning to this connection (address).
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_NO_SESSION_SPANNING    0x08
+
+/// Login response status details: Target does not support this type of session or not from this initiator.
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_SESSION_NO_SUPPORT     0x09
+
+/// Login response status details: Attempt to add a connection to a non-existent session.
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_SESSION_NO_EXIST       0x0A
+
+/// Login response status details: Invalid request type during login.
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_CLIENT_ERR_INVALID_LOGIN_REQ_TYPE 0x0B
+
+
+/**
+ * @brief Login response status class: Target Error.
+ *
+ * Indicates that the target sees no errors in the
+ * initiator's Login Request but is currently incapable of
+ * fulfilling the request. The initiator may retry the same Login
+ * Request later.
+ */
+#define ISCSI_LOGIN_RESPONSE_STATUS_CLASS_SERVER_ERR 0x03
+
+/// Login response status details: Target hardware or software error.
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_SERVER_ERR_TARGET_ERROR        0x00
+
+/// Login response status details: The iSCSI service or target is not currently operational.
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_SERVER_ERR_SERVICE_UNAVAILABLE 0x01
+
+/// The target has insufficient session, connection, or other resources.
+#define ISCSI_LOGIN_RESPONSE_STATUS_DETAILS_SERVER_ERR_OUT_OF_RESOURCES    0x02
+
+
+/**
+ * @brief iSCSI Login Response packet data.
+ *
+ * The Login Response indicates the progress and/or end of the Login
+ * Phase.
+ */
 typedef struct __attribute__((packed)) iscsi_login_response_packet {
-    uint8_t opcode; // Always 0x23 according to specification (see above)
-    int8_t flags; // Login response flags (see above)
-    uint8_t version_max; // This is the highest version number supported by the target.
-                         // All Login Responses within the Login Phase MUST carry the same
-                         // Version-max
-    uint8_t version_active; // Version-active indicates the highest version supported by the target
-                            // and initiator. If the target does not support a version within the
-                            // range specified by the initiator, the target rejects the login and
-                            // this field indicates the lowest version supported by the target.
-                            // All Login Responses within the Login Phase MUST carry the same
-                            // Version-active.
-                            // The initiator MUST use the value presented as a response to the first
-                            // Login Request
-    uint8_t total_ahs_len; // TotalAHSLength
-    uint8_t ds_len[3]; // DataSegmentLength
-    struct iscsi_isid isid; // ISID (see above for declaration)
-    uint16_t tsih; // The TSIH is the target-assigned session-identifying handle. Its
-                   // internal format and content are not defined by this protocol, except
-                   // for the value 0, which is reserved. With the exception of the Login
-                   // Final-Response in a new session, this field should be set to the TSIH
-                   // provided by the initiator in the Login Request. For a new session,
-                   // the target MUST generate a non-zero TSIH and ONLY return it in the
-                   // Login Final-Response
-    uint32_t init_task_tag; // Initiator task tag
-    uint32_t reserved; // Reserved for future usage
-    uint32_t stat_sn; // For the first Login Response (the response to the first Login
-                      // Request), this is the starting status sequence number for the
-                      // connection. The next response of any kind - including the next
-                      // Login Response, if any, in the same Login Phase - will carry this
-                      // number + 1. This field is only valid if the Status-Class is 0
-    uint32_t exp_cmd_sn; // ExpCmdSN
-    uint32_t max_cmd_sn; // MaxCmdSN
-    uint8_t status_class; // Status-class (see above for details). If the Status-Class is
-                          // not 0, the initiator and target MUST close the TCP connection
-                          // If the target wishes to reject the Login Request for more than one
-                          // reason, it should return the primary reason for the rejection
-    uint8_t status_detail; // Status-detail (see above for details)
-    uint16_t reserved2; // Reserved for future usage
-    uint64_t reserved3; // Reserved for future usage
-    struct iscsi_ds_cmd_data ds_cmd_data; // Data segment - Login Parameters in Text Request Format
-                                          // The target MUST provide some basic parameters in order to enable the
-                                          // initiator to determine if it is connected to the correct port and the
-                                          // initial text parameters for the security exchange.
-                                          // All the rules specified for Text Responses also hold for Login
-                                          // Responses
+    /// Always 0x23 according to iSCSI specification.
+    uint8_t opcode;
+
+    /// Login response flags.
+    int8_t flags;
+
+    /**
+     * @brief This is the highest version number supported by the target.
+     *
+     * All Login Responses within the Login Phase MUST carry the same
+     * Version-max.
+     */
+    uint8_t version_max;
+
+    /**
+     * @brief Version-active indicates the highest version supported by the target and initiator.
+     *
+     * If the target does not support a version within the
+     * range specified by the initiator, the target rejects the login and
+     * this field indicates the lowest version supported by the target.
+     * All Login Responses within the Login Phase MUST carry the same
+     * Version-active.\n
+     * The initiator MUST use the value presented as a response to the first
+     * Login Request.
+     */
+    uint8_t version_active;
+
+    /// TotalAHSLength.
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength.
+    uint8_t ds_len[3];
+
+    /// Initiator Session ID (ISID).
+    iscsi_isid isid;
+
+    /**
+     * @brief Target Session Identifying Handle (TSIH).
+     *
+     * The TSIH is the target-assigned session-identifying handle. Its
+     * internal format and content are not defined by this protocol, except
+     * for the value 0, which is reserved. With the exception of the Login
+     * Final-Response in a new session, this field should be set to the TSIH
+     * provided by the initiator in the Login Request. For a new session,
+     * the target MUST generate a non-zero TSIH and ONLY return it in the
+     * Login Final-Response.
+     */
+    uint16_t tsih;
+
+    /// Initiator Task Tag (ITT).
+    uint32_t init_task_tag;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved;
+
+    /**
+     * @brief StatSN.
+     *
+     * For the first Login Response (the response to the first Login
+     * Request), this is the starting status sequence number for the
+     * connection. The next response of any kind - including the next
+     * Login Response, if any, in the same Login Phase - will carry this
+     * number + 1. This field is only valid if the Status-Class is 0.
+     */
+    uint32_t stat_sn;
+
+    /// ExpCmdSN.
+    uint32_t exp_cmd_sn;
+
+    /// MaxCmdSN.
+    uint32_t max_cmd_sn;
+
+    /**
+     * @brief Status-class.
+     *
+     * Status-class (see above for details). If the Status-Class is
+     * not 0, the initiator and target MUST close the TCP connection
+     * If the target wishes to reject the Login Request for more than one
+     * reason, it should return the primary reason for the rejection.
+     */
+    uint8_t status_class;
+
+    /// Status-detail.
+    uint8_t status_detail;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint16_t reserved2;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint64_t reserved3;
+
+    /**
+     * @brief Data segment - Login Parameters in Text Request Format.
+     *
+     * The target MUST provide some basic parameters in order to enable the
+     * initiator to determine if it is connected to the correct port and the
+     * initial text parameters for the security exchange.\n
+     * All the rules specified for Text Responses also hold for Login
+     * Responses.
+     */
+    iscsi_ds_cmd_data ds_cmd_data;
 } iscsi_login_response_packet;
 
-#define ISCSI_LOGOUT_REQ_REASON_CODE_CLOSE_SESSION              0x00 // Close the session. All commands associated with the
-                                                                     // session (if any) are terminated
-#define ISCSI_LOGOUT_REQ_REASON_CODE_CLOSE_CONNECTION           0x01 // Close the connection. All commands associated with the
-                                                                     // connection (if any) are terminated
-#define ISCSI_LOGOUT_REQ_REASON_CODE_REMOVE_CONNECTION_RECOVERY 0x02 // Remove the connection for recovery. The connection is
-                                                                     // closed, and all commands associated with it, if any, are
-                                                                     // to be prepared for a new allegiance
-
-/* The entire logout discussion in this section is also applicable for
-   an implicit Logout realized by way of a connection reinstatement or
-   session reinstatement. When a Login Request performs an implicit
-   Logout, the implicit Logout is performed as if having the reason
-   codes specified below:
-*/
-#define ISCSI_LOGOUT_REQ_REASON_CODE_IMPLICIT_SESSION_REINSTATEMENT      0x00 // Session reinstatement
-#define ISCSI_LOGOUT_REQ_REASON_CODE_IMPLICIT_CONNECTION_REINSTATEMENT   0x01 // connection reinstatement when the operational
-                                                                              // ErrorRecoveryLevel < 2
-#define ISCSI_LOGOUT_REQ_REASON_CODE_IMPLICIT_CONNECTION_REINSTATEMENT_2 0x02 // connection reinstatement when the operational
-                                                                              // ErrorRecoveryLevel = 2
-
-/* The Logout Request is used to perform a controlled closing of a
-   connection.
-
-   An initiator MAY use a Logout Request to remove a connection from a
-   session or to close an entire session.
-
-   After sending the Logout Request PDU, an initiator MUST NOT send any
-   new iSCSI requests on the closing connection. If the Logout Request
-   is intended to close the session, new iSCSI requests MUST NOT be sent
-   on any of the connections participating in the session.
-
-   When receiving a Logout Request with the reason code "close the
-   connection" or "close the session", the target MUST terminate all
-   pending commands, whether acknowledged via the ExpCmdSN or not, on
-   that connection or session, respectively.
-
-   When receiving a Logout Request with the reason code "remove the
-   connection for recovery", the target MUST discard all requests not
-   yet acknowledged via the ExpCmdSN that were issued on the specified
-   connection and suspend all data/status/R2T transfers on behalf of
-   pending commands on the specified connection.
-
-   The target then issues the Logout Response and half-closes the TCP
-   connection (sends FIN). After receiving the Logout Response and
-   attempting to receive the FIN (if still possible), the initiator MUST
-   completely close the logging-out connection. For the terminated
-   commands, no additional responses should be expected.
-
-   A Logout for a CID may be performed on a different transport
-   connection when the TCP connection for the CID has already been
-   terminated. In such a case, only a logical "closing" of the iSCSI
-   connection for the CID is implied with a Logout.
-
-   All commands that were not terminated or not completed (with status)
-   and acknowledged when the connection is closed completely can be
-   reassigned to a new connection if the target supports connection
-   recovery.
-
-   If an initiator intends to start recovery for a failing connection,
-   it MUST use the Logout Request to "clean up" the target end of a
-   failing connection and enable recovery to start, or use the Login
-   Request with a non-zero TSIH and the same CID on a new connection for
-   the same effect. In sessions with a single connection, the
-   connection can be closed and then a new connection reopened. A
-   connection reinstatement login can be used for recovery.
-
-   A successful completion of a Logout Request with the reason code
-   "close the connection" or "remove the connection for recovery"
-   results at the target in the discarding of unacknowledged commands
-   received on the connection being logged out. These are commands that
-   have arrived on the connection being logged out but that have not
-   been delivered to SCSI because one or more commands with a smaller
-   CmdSN have not been received by iSCSI. The resulting holes in the
-   command sequence numbers will have to be handled by appropriate
-   recovery, unless the session is also closed.
-*/
+
+/// Logout request reason code: Close the session. All commands associated with the session (if any) are terminated.
+#define ISCSI_LOGOUT_REQ_REASON_CODE_CLOSE_SESSION              0x00
+
+/// Logout request reason code: Close the connection. All commands associated with the connection (if any) are terminated.
+#define ISCSI_LOGOUT_REQ_REASON_CODE_CLOSE_CONNECTION           0x01
+
+/// Logout request reason code: Remove the connection for recovery. The connection is closed, and all commands associated with it, if any, are to be prepared for a new allegiance.
+#define ISCSI_LOGOUT_REQ_REASON_CODE_REMOVE_CONNECTION_RECOVERY 0x02
+
+
+/**
+ * @brief Logout request implicit reason code: Session reinstatement.
+ *
+ * The entire logout discussion in this section is also applicable for
+ * an implicit Logout realized by way of a connection reinstatement or
+ * session reinstatement. When a Login Request performs an implicit
+ * Logout, the implicit Logout is performed as if having the reason
+ * codes specified below:
+ */
+#define ISCSI_LOGOUT_REQ_REASON_CODE_IMPLICIT_SESSION_REINSTATEMENT      0x00
+
+/**
+ * @brief Logout request implicit reason code: Connection reinstatement when the operational ErrorRecoveryLevel < 2.
+ *
+ * The entire logout discussion in this section is also applicable for
+ * an implicit Logout realized by way of a connection reinstatement or
+ * session reinstatement. When a Login Request performs an implicit
+ * Logout, the implicit Logout is performed as if having the reason
+ * codes specified below:
+ */
+#define ISCSI_LOGOUT_REQ_REASON_CODE_IMPLICIT_CONNECTION_REINSTATEMENT   0x01
+
+/**
+ * @brief Logout request implicit reason code: Connection reinstatement when the operational ErrorRecoveryLevel = 2.
+ *
+ * The entire logout discussion in this section is also applicable for
+ * an implicit Logout realized by way of a connection reinstatement or
+ * session reinstatement. When a Login Request performs an implicit
+ * Logout, the implicit Logout is performed as if having the reason
+ * codes specified below:
+ */
+#define ISCSI_LOGOUT_REQ_REASON_CODE_IMPLICIT_CONNECTION_REINSTATEMENT_2 0x02
+
+
+/**
+ * @brief iSCSI Logout Request packet data.
+ *
+ * The Logout Request is used to perform a controlled closing of a
+ * connection.
+ *
+ * An initiator MAY use a Logout Request to remove a connection from a
+ * session or to close an entire session.
+ *
+ * After sending the Logout Request PDU, an initiator MUST NOT send any
+ * new iSCSI requests on the closing connection. If the Logout Request
+ * is intended to close the session, new iSCSI requests MUST NOT be sent
+ * on any of the connections participating in the session.
+ *
+ * When receiving a Logout Request with the reason code "close the
+ * connection" or "close the session", the target MUST terminate all
+ * pending commands, whether acknowledged via the ExpCmdSN or not, on
+ * that connection or session, respectively.
+ *
+ * When receiving a Logout Request with the reason code "remove the
+ * connection for recovery", the target MUST discard all requests not
+ * yet acknowledged via the ExpCmdSN that were issued on the specified
+ * connection and suspend all data/status/R2T transfers on behalf of
+ * pending commands on the specified connection.
+ *
+ * The target then issues the Logout Response and half-closes the TCP
+ * connection (sends FIN). After receiving the Logout Response and
+ * attempting to receive the FIN (if still possible), the initiator MUST
+ * completely close the logging-out connection. For the terminated
+ * commands, no additional responses should be expected.
+ *
+ * A Logout for a CID may be performed on a different transport
+ * connection when the TCP connection for the CID has already been
+ * terminated. In such a case, only a logical "closing" of the iSCSI
+ * connection for the CID is implied with a Logout.
+ *
+ * All commands that were not terminated or not completed (with status)
+ * and acknowledged when the connection is closed completely can be
+ * reassigned to a new connection if the target supports connection
+ * recovery.
+ *
+ * If an initiator intends to start recovery for a failing connection,
+ * it MUST use the Logout Request to "clean up" the target end of a
+ * failing connection and enable recovery to start, or use the Login
+ * Request with a non-zero TSIH and the same CID on a new connection for
+ * the same effect. In sessions with a single connection, the
+ * connection can be closed and then a new connection reopened. A
+ * connection reinstatement login can be used for recovery.
+ *
+ * A successful completion of a Logout Request with the reason code
+ * "close the connection" or "remove the connection for recovery"
+ * results at the target in the discarding of unacknowledged commands
+ * received on the connection being logged out. These are commands that
+ * have arrived on the connection being logged out but that have not
+ * been delivered to SCSI because one or more commands with a smaller
+ * CmdSN have not been received by iSCSI. The resulting holes in the
+ * command sequence numbers will have to be handled by appropriate
+ * recovery, unless the session is also closed.
+ */
 typedef struct __attribute__((packed)) iscsi_logout_req_packet {
-    uint8_t opcode; // Always 0x06 according to specification (see above)
-    int8_t reason_code; // Reason Code
-                        // A target implicitly terminates the active tasks due to the iSCSI
-                        // protocol in the following cases:
-                        // a) When a connection is implicitly or explicitly logged out with
-                        //    the reason code "close the connection" and there are active
-                        //    tasks allegiant to that connection.
-                        // b) When a connection fails and eventually the connection state
-                        //    times out and there are active tasks allegiant to that
-                        //    connection
-                        // c) When a successful recovery Logout is performed while there are
-                        //    active tasks allegiant to that connection and those tasks
-                        //    eventually time out after the Time2Wait and Time2Retain periods
-                        //    without allegiance reassignment
-                        // d) When a connection is implicitly or explicitly logged out with
-                        //    the reason code "close the session" and there are active tasks
-                        //    in that session
-                        // If the tasks terminated in any of the above cases are SCSI tasks,
-                        // they must be internally terminated as if with CHECK CONDITION status.
-                        // This status is only meaningful for appropriately handling the
-                        // internal SCSI state and SCSI side effects with respect to ordering,
-                        // because this status is never communicated back as a terminating
-                        // status to the initiator. However, additional actions may have to be
-                        // taken at the SCSI level, depending on the SCSI context as defined by
-                        // the SCSI standards (e.g., queued commands and ACA; UA for the next
-                        // command on the I_T nexus in cases a), b), and c) above). After the
-                        // tasks are terminated, the target MUST report a Unit Attention condition
-                        // on the next command processed on any connection for each affected
-                        // I_T_L nexus with the status of CHECK CONDITION, the ASC/ASCQ value
-                        // of 0x47 / 0x7F ("SOME COMMANDS CLEARED BY ISCSI PROTOCOL EVENT"), etc.
-    uint16_t reserved; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength (MUST be 0 for this PDU)
-    uint8_t ds_len[3]; // DataSegmentLength (MUST be 0 for this PDU)
-    uint64_t reserved2; // Reserved for future usage
-    uint32_t init_task_tag; // Initiator task tag
-    uint16_t cid; // This is the connection ID of the connection to be closed (including
-                  // closing the TCP stream). This field is only valid if the reason code
-                  // is not "close the session"
-    uint16_t reserved3; // Reserved for future usage
-    uint32_t cmd_sn; // CmdSN
-    uint32_t exp_stat_sn; // This is the last ExpStatSN value for the connection to be closed
-    uint64_t reserved4[2]; // Reserved for future usage
-    struct iscsi_header_digest hdr_digest; // Optional header digest
+    /// Always 6 according to iSCSI specification.
+    uint8_t opcode;
+
+    /**
+     * @brief Reason code.
+     *
+     * A target implicitly terminates the active tasks due to the iSCSI
+     * protocol in the following cases:
+     * -# When a connection is implicitly or explicitly logged out with
+     *    the reason code "close the connection" and there are active
+     *    tasks allegiant to that connection.
+     * -# When a connection fails and eventually the connection state
+     *    times out and there are active tasks allegiant to that
+     *    connection
+     * -# When a successful recovery Logout is performed while there are
+     *    active tasks allegiant to that connection and those tasks
+     *    eventually time out after the Time2Wait and Time2Retain periods
+     *    without allegiance reassignment
+     * -# When a connection is implicitly or explicitly logged out with
+     *    the reason code "close the session" and there are active tasks
+     *    in that session
+     *
+     * If the tasks terminated in any of the above cases are SCSI tasks,
+     * they must be internally terminated as if with CHECK CONDITION status.
+     * This status is only meaningful for appropriately handling the
+     * internal SCSI state and SCSI side effects with respect to ordering,
+     * because this status is never communicated back as a terminating
+     * status to the initiator. However, additional actions may have to be
+     * taken at the SCSI level, depending on the SCSI context as defined by
+     * the SCSI standards (e.g., queued commands and ACA; UA for the next
+     * command on the I_T nexus in cases a), b), and c) above). After the
+     * tasks are terminated, the target MUST report a Unit Attention condition
+     * on the next command processed on any connection for each affected
+     * I_T_L nexus with the status of CHECK CONDITION, the ASC/ASCQ value
+     * of 0x47 / 0x7F ("SOME COMMANDS CLEARED BY ISCSI PROTOCOL EVENT"), etc.
+     */
+    int8_t reason_code;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint16_t reserved;
+
+    /// TotalAHSLength (MUST be 0 for this PDU).
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength (MUST be 0 for this PDU).
+    uint8_t ds_len[3];
+
+    /// Reserved for future usage, always MUST be 0.
+    uint64_t reserved2;
+
+    /// Initiator Task Tag (ITT).
+    uint32_t init_task_tag;
+
+    /**
+     * @brief Connection ID (CID).
+     *
+     * This is the connection ID of the connection to be closed (including
+     * closing the TCP stream). This field is only valid if the reason code
+     * is not "close the session".
+     */
+    uint16_t cid;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint16_t reserved3;
+
+    /// CmdSN.
+    uint32_t cmd_sn;
+
+    /// This is the last ExpStatSN value for the connection to be closed.
+    uint32_t exp_stat_sn;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint64_t reserved4[2];
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
 } iscsi_logout_req_packet;
 
-#define ISCSI_LOGOUT_RESPONSE_CLOSED_SUCCESSFULLY               0x00 // Connection or session closed successfully
-#define ISCSI_LOGOUT_RESPONSE_CID_NOT_FOUND                     0x01 // CID not found
-#define ISCSI_LOGOUT_RESPONSE_CONNECTION_RECOVERY_NOT_SUPPORTED 0x02 // Connection recovery is not supported (i.e., the Logout reason
-                                                                     // code was "remove the connection for recovery" and the target
-                                                                     // does not support it as indicated by the operational
-                                                                     // ErrorRecoveryLevel)
-#define ISCSI_LOGOUT_RESPONSE_CLEANUP_FAILED                    0x03 // Cleanup failed for various reasons
 
-/* The Logout Response is used by the target to indicate if the cleanup
-   operation for the connection(s) has completed.
+/// Logout response - response code: Connection or session closed successfully.
+#define ISCSI_LOGOUT_RESPONSE_CLOSED_SUCCESSFULLY               0x00
 
-   After Logout, the TCP connection referred by the CID MUST be closed
-   at both ends (or all connections must be closed if the logout reason
-   was session close).
-*/
+/// Logout response - response code: Connection ID (CID) not found.
+#define ISCSI_LOGOUT_RESPONSE_CID_NOT_FOUND                     0x01
+
+/// Logout response - response code: Connection recovery is not supported (i.e., the Logout reason code was "remove the connection for recovery" and the target does not support it as indicated by the operational ErrorRecoveryLevel).
+#define ISCSI_LOGOUT_RESPONSE_CONNECTION_RECOVERY_NOT_SUPPORTED 0x02
+
+/// Logout response - response code: Cleanup failed for various reasons.
+#define ISCSI_LOGOUT_RESPONSE_CLEANUP_FAILED                    0x03
+
+/**
+ * @brief iSCSI Logout Response packet data.
+ *
+ * The Logout Response is used by the target to indicate if the cleanup
+ * operation for the connection(s) has completed.
+ *
+ * After Logout, the TCP connection referred by the CID MUST be closed
+ * at both ends (or all connections must be closed if the logout reason
+ * was session close).
+ */
 typedef struct __attribute__((packed)) iscsi_logout_response_packet {
-    uint8_t opcode; // Always 0x26 according to specification (see above)
-    uint8_t flags; // Reserved for future usage
-    uint8_t response; // Response
-    uint8_t reserved; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength (MUST be 0 for this PDU)
-    uint8_t ds_len[3]; // DataSegmentLength (MUST be 0 for this PDU)
-    uint64_t reserved2; // Reserved for future usage
-    uint32_t init_task_tag; // Initiator task tag
-    uint32_t reserved3; // Reserved for future usage
-    uint32_t stat_sn; // StatSN
-    uint32_t exp_cmd_sn; // ExpCmdSN
-    uint32_t max_cmd_sn; // MaxCmdSN
-    uint32_t reserved4; // Reserved for future usage
-    uint16_t time_wait; // Time2Wait
-                        // If the Logout response code is 0 and the operational
-                        // ErrorRecoveryLevel is 2, this is the minimum amount of time, in
-                        // seconds, to wait before attempting task reassignment. If the Logout
-                        // response code is 0 and the operational ErrorRecoveryLevel is less
-                        // than 2, this field is to be ignored.
-                        // This field is invalid if the Logout response code is 1.
-                        // If the Logout response code is 2 or 3, this field specifies the
-                        // minimum time to wait before attempting a new implicit or explicit
-                        // logout.
-                        // If Time2Wait is 0, the reassignment or a new Logout may be attempted
-                        // immediately
-    uint16_t time_retain; // Time2Retain
-                          // If the Logout response code is 0 and the operational
-                          // ErrorRecoveryLevel is 2, this is the maximum amount of time, in
-                          // seconds, after the initial wait (Time2Wait) that the target waits for
-                          // the allegiance reassignment for any active task, after which the task
-                          // state is discarded. If the Logout response code is 0 and the
-                          // operational ErrorRecoveryLevel is less than 2, this field is to be
-                          // ignored.
-                          // This field is invalid if the Logout response code is 1.
-                          // If the Logout response code is 2 or 3, this field specifies the
-                          // maximum amount of time, in seconds, after the initial wait
-                          // (Time2Wait) that the target waits for a new implicit or explicit
-                          // logout.
-                          // If it is the last connection of a session, the whole session state is
-                          // discarded after Time2Retain.
-                          // If Time2Retain is 0, the target has already discarded the connection
-                          // (and possibly the session) state along with the task states. No
-                          // reassignment or Logout is required in this case
-    uint32_t reserved5; // Reserved for future usage
-    struct iscsi_header_digest hdr_digest; // Optional header digest
+    /// Always 0x26 according to iSCSI specification.
+    uint8_t opcode;
+
+    /// Reserved for future usage (must be always 0x80 for now).
+    int8_t flags;
+
+    /// Response.
+    uint8_t response;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint8_t reserved;
+
+    /// TotalAHSLength (MUST be 0 for this PDU).
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength (MUST be 0 for this PDU).
+    uint8_t ds_len[3];
+
+    /// Reserved for future usage, always MUST be 0.
+    uint64_t reserved2;
+
+    /// Initiator Task Tag (ITT).
+    uint32_t init_task_tag;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved3;
+
+    /// StatSN.
+    uint32_t stat_sn;
+
+    /// ExpCmdSN.
+    uint32_t exp_cmd_sn;
+
+    /// MaxCmdSN.
+    uint32_t max_cmd_sn;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved4;
+
+    /**
+     * @brief Time2Wait.
+     *
+     * If the Logout response code is 0 and the operational
+     * ErrorRecoveryLevel is 2, this is the minimum amount of time, in
+     * seconds, to wait before attempting task reassignment. If the Logout
+     * response code is 0 and the operational ErrorRecoveryLevel is less
+     * than 2, this field is to be ignored.\n
+     * This field is invalid if the Logout response code is 1.\n
+     * If the Logout response code is 2 or 3, this field specifies the
+     * minimum time to wait before attempting a new implicit or explicit
+     * logout.\n
+     * If Time2Wait is 0, the reassignment or a new Logout may be attempted
+     * immediately.
+     */
+    uint16_t time_wait;
+
+    /**
+     * @brief Time2Retain.
+     *
+     * If the Logout response code is 0 and the operational
+     * ErrorRecoveryLevel is 2, this is the maximum amount of time, in
+     * seconds, after the initial wait (Time2Wait) that the target waits for
+     * the allegiance reassignment for any active task, after which the task
+     * state is discarded. If the Logout response code is 0 and the
+     * operational ErrorRecoveryLevel is less than 2, this field is to be
+     * ignored.\n
+     * This field is invalid if the Logout response code is 1.\n
+     * If the Logout response code is 2 or 3, this field specifies the
+     * maximum amount of time, in seconds, after the initial wait
+     * (Time2Wait) that the target waits for a new implicit or explicit
+     * logout.\n
+     * If it is the last connection of a session, the whole session state is
+     * discarded after Time2Retain.\n
+     * If Time2Retain is 0, the target has already discarded the connection
+     * (and possibly the session) state along with the task states. No
+     * reassignment or Logout is required in this case.
+     */
+    uint16_t time_retain;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved5;
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
 } iscsi_logout_response_packet;
 
-#define ISCSI_SNACK_REQ_TYPE_DATA_R2T_SNACK 0x00 // Data/R2T SNACK: requesting retransmission of one or more
-                                                 // Data-In or R2T PDUs
+
+/// Selective Negative / Sequence Number Acknowledgment (SNACK) request: Data/R2T SNACK: requesting retransmission of one or more Data-In or R2T PDUs.
+#define ISCSI_SNACK_REQ_TYPE_DATA_R2T_SNACK 0x00
+
+/// Selective Negative / Sequence Number Acknowledgment (SNACK) request:
 #define ISCSI_SNACK_REQ_TYPE_STATUS_SNACK   0x01 // Status SNACK: requesting retransmission of one or more
                                                  // numbered responses
-#define ISCSI_SNACK_REQ_TYPE_DATA_ACK       0x02 // DataACK: positively acknowledges Data-In PDUs.
-                                                 // If an initiator operates at ErrorRecoveryLevel 1 or higher, it MUST
-                                                 // issue a SNACK of type DataACK after receiving a Data-In PDU with the
-                                                 // A bit set to 1. However, if the initiator has detected holes in the
-                                                 // input sequence, it MUST postpone issuing the SNACK of type DataACK
-                                                 // until the holes are filled. An initiator MAY ignore the A bit if it
-                                                 // deems that the bit is being set aggressively by the target (i.e.,
-                                                 // before the MaxBurstLength limit is reached).
-                                                 // The DataACK is used to free resources at the target and not to
-                                                 // request or imply data retransmission.
-                                                 // An initiator MUST NOT request retransmission for any data it had
-                                                 // already acknowledged
-#define ISCSI_SNACK_REQ_TYPE_R_DATA_SNACK   0x03 // R-Data SNACK: requesting retransmission of Data-In PDUs with
-                                                 // possible resegmentation and status tagging.
-                                                 // If the initiator MaxRecvDataSegmentLength changed between the
-                                                 // original transmission and the time the initiator requests
-                                                 // retransmission, the initiator MUST issue a R-Data SNACK.
-                                                 // With R-Data SNACK, the initiator indicates that it discards all the
-                                                 // unacknowledged data and expects the target to resend it. It also
-                                                 // expects resegmentation. In this case, the retransmitted Data-In PDUs
-                                                 // MAY be different from the ones originally sent in order to reflect
-                                                 // changes in MaxRecvDataSegmentLength. Their DataSN starts with the
-                                                 // BegRun of the last DataACK received by the target if any was received;
-                                                 // otherwise, it starts with 0 and is increased by 1 for each resent
-                                                 // Data-In PDU.
-                                                 // A target that has received a R-Data SNACK MUST return a SCSI Response
-                                                 // that contains a copy of the SNACK Tag field from the R-Data SNACK in
-                                                 // the SCSI Response SNACK Tag field as its last or only Response. For
-                                                 // example, if it has already sent a response containing another value
-                                                 // in the SNACK Tag field or had the status included in the last Data-In
-                                                 // PDU, it must send a new SCSI Response PDU. If a target sends more
-                                                 // than one SCSI Response PDU due to this rule, all SCSI Response PDUs
-                                                 // must carry the same StatSN. If an initiator attempts to recover a lost
-                                                 // SCSI Response when more than one response has been sent, the
-                                                 // target will send the SCSI Response with the latest content known to
-                                                 // the target, including the last SNACK Tag for the command.
-                                                 // For considerations in allegiance reassignment of a task to a
-                                                 // connection with a different MaxRecvDataSegmentLength.
-
-/* If the implementation supports ErrorRecoveryLevel greater than zero,
-   it MUST support all SNACK types.
-
-   The SNACK is used by the initiator to request the retransmission of
-   numbered responses, data, or R2T PDUs from the target. The SNACK
-   Request indicates the numbered responses or data "runs" whose
-   retransmission is requested, where the run starts with the first
-   StatSN, DataSN, or R2TSN whose retransmission is requested and
-   indicates the number of Status, Data, or R2T PDUs requested,
-   including the first. 0 has special meaning when used as a starting
-   number and length:
-
-      - When used in RunLength, it means all PDUs starting with the
-        initial.
-
-      - When used in both BegRun and RunLength, it means all
-        unacknowledged PDUs.
-
-   The numbered response(s) or R2T(s) requested by a SNACK MUST be
-   delivered as exact replicas of the ones that the target transmitted
-   originally, except for the fields ExpCmdSN, MaxCmdSN, and ExpDataSN,
-   which MUST carry the current values. R2T(s)requested by SNACK MUST
-   also carry the current value of the StatSN.
-
-   The numbered Data-In PDUs requested by a Data SNACK MUST be delivered
-   as exact replicas of the ones that the target transmitted originally,
-   except for the fields ExpCmdSN and MaxCmdSN, which MUST carry the
-   current values; and except for resegmentation.
-
-   Any SNACK that requests a numbered response, data, or R2T that was
-   not sent by the target or was already acknowledged by the initiator
-   MUST be rejected with a reason code of "Protocol Error".
-*/
+
+/**
+ * @brief Selective Negative / Sequence Number Acknowledgment (SNACK) request: DataACK: positively acknowledges Data-In PDUs.
+ *
+ * If an initiator operates at ErrorRecoveryLevel 1 or higher, it MUST
+ * issue a SNACK of type DataACK after receiving a Data-In PDU with the
+ * A bit set to 1. However, if the initiator has detected holes in the
+ * input sequence, it MUST postpone issuing the SNACK of type DataACK
+ * until the holes are filled. An initiator MAY ignore the A bit if it
+ * deems that the bit is being set aggressively by the target (i.e.,
+ * before the MaxBurstLength limit is reached).\n
+ * The DataACK is used to free resources at the target and not to
+ * request or imply data retransmission.\n
+ * An initiator MUST NOT request retransmission for any data it had
+ * already acknowledged
+ */
+#define ISCSI_SNACK_REQ_TYPE_DATA_ACK       0x02
+
+/**
+ * @brief Selective Negative / Sequence Number Acknowledgment (SNACK) request: R-Data SNACK: requesting retransmission of Data-In PDUs with possible resegmentation and status tagging.
+ *
+ * If the initiator MaxRecvDataSegmentLength changed between the
+ * original transmission and the time the initiator requests
+ * retransmission, the initiator MUST issue a R-Data SNACK.\n
+ * With R-Data SNACK, the initiator indicates that it discards all the
+ * unacknowledged data and expects the target to resend it. It also
+ * expects resegmentation. In this case, the retransmitted Data-In PDUs
+ * MAY be different from the ones originally sent in order to reflect
+ * changes in MaxRecvDataSegmentLength. Their DataSN starts with the
+ * BegRun of the last DataACK received by the target if any was received;
+ * otherwise, it starts with 0 and is increased by 1 for each resent
+ * Data-In PDU.\n
+ * A target that has received a R-Data SNACK MUST return a SCSI Response
+ * that contains a copy of the SNACK Tag field from the R-Data SNACK in
+ * the SCSI Response SNACK Tag field as its last or only Response. For
+ * example, if it has already sent a response containing another value
+ * in the SNACK Tag field or had the status included in the last Data-In
+ * PDU, it must send a new SCSI Response PDU. If a target sends more
+ * than one SCSI Response PDU due to this rule, all SCSI Response PDUs
+ * must carry the same StatSN. If an initiator attempts to recover a lost
+ * SCSI Response when more than one response has been sent, the
+ * target will send the SCSI Response with the latest content known to
+ * the target, including the last SNACK Tag for the command.\n
+ * For considerations in allegiance reassignment of a task to a
+ * connection with a different MaxRecvDataSegmentLength.
+ */
+#define ISCSI_SNACK_REQ_TYPE_R_DATA_SNACK   0x03
+
+
+/**
+ * @brief iSCSI SNACK Request packet data.
+ *
+ * If the implementation supports ErrorRecoveryLevel greater than zero,
+ * it MUST support all SNACK types.
+ *
+ * The SNACK is used by the initiator to request the retransmission of
+ * numbered responses, data, or R2T PDUs from the target. The SNACK
+ * Request indicates the numbered responses or data "runs" whose
+ * retransmission is requested, where the run starts with the first
+ * StatSN, DataSN, or R2TSN whose retransmission is requested and
+ * indicates the number of Status, Data, or R2T PDUs requested,
+ * including the first. 0 has special meaning when used as a starting
+ * number and length:
+ *
+ *    - When used in RunLength, it means all PDUs starting with the
+ *      initial.
+ *
+ *    - When used in both BegRun and RunLength, it means all
+ *      unacknowledged PDUs.
+ *
+ * The numbered response(s) or R2T(s) requested by a SNACK MUST be
+ * delivered as exact replicas of the ones that the target transmitted
+ * originally, except for the fields ExpCmdSN, MaxCmdSN, and ExpDataSN,
+ * which MUST carry the current values. R2T(s)requested by SNACK MUST
+ * also carry the current value of the StatSN.
+ *
+ * The numbered Data-In PDUs requested by a Data SNACK MUST be delivered
+ * as exact replicas of the ones that the target transmitted originally,
+ * except for the fields ExpCmdSN and MaxCmdSN, which MUST carry the
+ * current values; and except for resegmentation.
+ *
+ * Any SNACK that requests a numbered response, data, or R2T that was
+ * not sent by the target or was already acknowledged by the initiator
+ * MUST be rejected with a reason code of "Protocol Error".
+ */
 typedef struct __attribute__((packed)) iscsi_snack_req_packet {
-    uint8_t opcode; // Always 0x10 according to specification (see above)
-    int8_t type; // Type
-                 // Data/R2T SNACK, Status SNACK, or R-Data SNACK for a command MUST
-                 // precede status acknowledgment for the given command
-    uint16_t reserved; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength
-    uint8_t ds_len[3]; // DataSegmentLength
-    uint64_t lun; // LUN or Reserved
-    uint32_t init_task_tag; // For a Status SNACK and DataACK, the Initiator Task Tag MUST be set to
-                            // the reserved value 0xFFFFFFFF. In all other cases, the Initiator
-                            // Task Tag field MUST be set to the Initiator Task Tag of the
-                            // referenced command
-    uint32_t target_xfer_snack_tag; // For a R-Data SNACK, this field MUST contain a value that is different
-                                    // from 0 or 0xFFFFFFFF and is unique for the task (identified by the
-                                    // Initiator Task Tag). This value MUST be copied by the iSCSI target
-                                    // in the last or only SCSI Response PDU it issues for the command.
-                                    // For DataACK, the Target Transfer Tag MUST contain a copy of the
-                                    // Target Transfer Tag and LUN provided with the SCSI Data-In PDU with
-                                    // the A bit set to 1.
-                                    // In all other cases, the Target Transfer Tag field MUST be set to the
-                                    // reserved value 0xFFFFFFFF
-    uint32_t reserved2; // Reserved for future usage
-    uint32_t exp_stat_sn; // ExpStatSN
-    uint32_t reserved3; // Reserved for future usage
-    uint32_t beg_run; // BegRun
-                      // This field indicates the DataSN, R2TSN, or StatSN of the first PDU
-                      // whose retransmission is requested (Data/R2T and Status SNACK), or the
-                      // next expected DataSN (DataACK SNACK).
-                      // A BegRun of 0, when used in conjunction with a RunLength of 0, means
-                      // "resend all unacknowledged Data-In, R2T or Response PDUs".
-                      // BegRun MUST be 0 for a R-Data SNACK
-    uint32_t run_len; // RunLength
-                      // This field indicates the number of PDUs whose retransmission is
-                      // requested.
-                      // A RunLength of 0 signals that all Data-In, R2T, or Response PDUs
-                      // carrying the numbers equal to or greater than BegRun have to be
-                      // resent.
-                      // The RunLength MUST also be 0 for a DataACK SNACK in addition to a
-                      // R-Data SNACK
-    struct iscsi_header_digest hdr_digest; // Optional header digest
+    /// Always 0x10 according to iSCSI specification.
+    uint8_t opcode;
+
+    /**
+     * @brief Type.
+     *
+     * Data/R2T SNACK, Status SNACK, or R-Data SNACK for a command MUST
+     * precede status acknowledgment for the given command.
+     */
+    int8_t type;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint16_t reserved;
+
+    /// TotalAHSLength.
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength.
+    uint8_t ds_len[3];
+
+    /// LUN or Reserved.
+    uint64_t lun;
+
+    /**
+     * @brief Initiator Task Tag (ITT).
+     *
+     * For a Status SNACK and DataACK, the Initiator Task Tag MUST be set to
+     * the reserved value 0xFFFFFFFF. In all other cases, the Initiator
+     * Task Tag field MUST be set to the Initiator Task Tag of the
+     * referenced command.
+     */
+    uint32_t init_task_tag;
+
+    /**
+     * @brief Target Transfer Tag (TTT).
+     *
+     * For a R-Data SNACK, this field MUST contain a value that is different
+     * from 0 or 0xFFFFFFFF and is unique for the task (identified by the
+     * Initiator Task Tag). This value MUST be copied by the iSCSI target
+     * in the last or only SCSI Response PDU it issues for the command.\n
+     * For DataACK, the Target Transfer Tag MUST contain a copy of the
+     * Target Transfer Tag and LUN provided with the SCSI Data-In PDU with
+     * the A bit set to 1.\n
+     * In all other cases, the Target Transfer Tag field MUST be set to the
+     * reserved value 0xFFFFFFFF.
+     */
+    uint32_t target_xfer_snack_tag;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved2;
+
+    /// ExpStatSN.
+    uint32_t exp_stat_sn;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved3;
+
+    /**
+     * @brief BegRun.
+     *
+     * This field indicates the DataSN, R2TSN, or StatSN of the first PDU
+     * whose retransmission is requested (Data/R2T and Status SNACK), or the
+     * next expected DataSN (DataACK SNACK).\n
+     * A BegRun of 0, when used in conjunction with a RunLength of 0, means
+     * "resend all unacknowledged Data-In, R2T or Response PDUs".
+     * BegRun MUST be 0 for a R-Data SNACK.
+     */
+    uint32_t beg_run;
+
+    /**
+     * @brief RunLength.
+     *
+     * This field indicates the number of PDUs whose retransmission is
+     * requested.\n
+     * A RunLength of 0 signals that all Data-In, R2T, or Response PDUs
+     * carrying the numbers equal to or greater than BegRun have to be
+     * resent.\n
+     * The RunLength MUST also be 0 for a DataACK SNACK in addition to a
+     * R-Data SNACK.
+     */
+    uint32_t run_len;
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
 } iscsi_snack_req_packet;
 
-#define ISCSI_REJECT_REASON_RESERVED                    0x01 // Reserved, original PDU can't be resent
-#define ISCSI_REJECT_REASON_DATA_DIGEST_ERR             0x02 // Data (payload) digest error, original
-                                                             // PDU can be resent.
-                                                             // For iSCSI, Data-Out PDU retransmission is only done if the
-                                                             // target requests retransmission with a recovery R2T. However,
-                                                             // if this is the data digest error on immediate data, the
-                                                             // initiator may choose to retransmit the whole PDU, including
-                                                             // the immediate data
-#define ISCSI_REJECT_REASON_SNACK_REJECT                0x03 // SNACK Reject (original PDU can be resent)
-#define ISCSI_REJECT_REASON_PROTOCOL_ERR                0x04 // Protocol Error (e.g., SNACK Request for a status that was
-                                                             // already acknowledged). Original PDU can't be resent'
-#define ISCSI_REJECT_REASON_COMMAND_NOT_SUPPORTED       0x05 // Command not supported (original PDU can't be resent)
-#define ISCSI_REJECT_REASON_TOO_MANY_IMMEDIATE_COMMANDS 0x06 // Immediate command reject - too many immediate
-                                                             // commands (original PDU can be resent)
-#define ISCSI_REJECT_REASON_TASK_IN_PROGRESS            0x07 // Task in progress (original PDU can't be resent)
-#define ISCSI_REJECT_REASON_INVALID_DATA_ACK            0x08 // Invalid data ack (original PDU can't be resent)
-#define ISCSI_REJECT_REASON_INVALID_PDU_FIELD           0x09 // Invalid PDU field, original PDU can't be resent.
-                                                             // A target should use this reason code for all invalid values
-                                                             // of PDU fields that are meant to describe a task, a response,
-                                                             // or a data transfer. Some examples are invalid TTT/ITT,
-                                                             // buffer offset, LUN qualifying a TTT, and an invalid sequence
-                                                             // number in a SNACK
-#define ISCSI_REJECT_REASON_OUT_OF_RESOURCES            0x0A // Long op reject - Can't generate Target Transfer Tag - out of
-                                                             // resources. Original PDU can be resent later
-#define ISCSI_REJECT_REASON_DEPRECATED                  0x0B // Deprecated; MUST NOT be used. Reason code 0x0B is deprecated
-                                                             // and MUST NOT be used by implementations. An implementation
-                                                             // receiving reason code 0x0B MUST treat it as a negotiation
-                                                             // failure that terminates the Login Phase and the TCP connection
-#define ISCSI_REJECT_REASON_WAITING_FOR_LOGOUT          0x0C // Waiting for Logout, original PDU can't be resent
 
-typedef struct __attribute__((packed)) iscsi_reject_packet {
-    uint8_t opcode; // Always 0x3F according to specification (see above)
-    uint8_t flags; // Reserved for future usage
-    uint8_t reason; // Reject reason (see above for definitions).
-                    // In all the cases in which a pre-instantiated SCSI task is terminated
-                    // because of the reject, the target MUST issue a proper SCSI command
-                    // response with CHECK CONDITION. In these cases in which a status for
-                    // the SCSI task was already sent before the reject, no additional
-                    // status is required. If the error is detected while data from the
-                    // initiator is still expected (i.e., the command PDU did not contain
-                    // all the data and the target has not received a Data-Out PDU with the
-                    // Final bit set to 1 for the unsolicited data, if any, and all
-                    // outstanding R2Ts, if any), the target MUST wait until it receives
-                    // the last expected Data-Out PDUs with the F bit set to 1 before
-                    // sending the Response PDU
-    uint8_t reserved; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength
-    uint8_t ds_len[3]; // DataSegmentLength
-    uint64_t reserved2; // Reserved for future usage
-    uint32_t tag; // Always 0xFFFFFFFF for now
-    uint32_t reserved3; // Reserved for future usage
-    uint32_t stat_sn; // StatSN. This field carries its usual value and is not related to the
-                      // rejected command. The StatSN is advanced after a Reject
-    uint32_t exp_cmd_sn; // ExpCmdSN. This field carries its usual value and is not related to the
-                         // rejected command
-    uint32_t max_cmd_sn; // MaxCmdSN. This field carries its usual value and is not related to the
-                         // rejected command
-    uint32_t data_r2tsn_sn; // DataSN/R2TSN or Reserved.
-                            // This field is only valid if the rejected PDU is a Data/R2T SNACK and
-                            // the Reject reason code is "Protocol Error". The DataSN/R2TSN is the
-                            // next Data/R2T sequence number that the target would send for the
-                            // task, if any
-    uint32_t reserved4[2]; // Reserved for future usage
-    struct iscsi_header_digest hdr_digest; // Optional header digest
-    struct iscsi_bhs_packet bad_pdu_hdr; // Complete Header of Bad PDU. The target returns the
-                                         // header (not including the digest) of the PDU in error
-                                         // as the data of the response
-    uint8_t vendor_data[0]; // Vendor-specific data (if any)
-    struct iscsi_data_digest data_digest; // Optional data digest
-} iscsi_reject_packet;
+/// iSCSI Reject packet data: Reserved, original PDU can't be resent.
+#define ISCSI_REJECT_REASON_RESERVED                    0x01
+
+/**
+ * @brief iSCSI Reject packet data: Data (payload) digest error, original PDU can be resent.
+ *
+ * For iSCSI, Data-Out PDU retransmission is only done if the
+ * target requests retransmission with a recovery R2T. However,
+ * if this is the data digest error on immediate data, the
+ * initiator may choose to retransmit the whole PDU, including
+ * the immediate data.
+ */
+#define ISCSI_REJECT_REASON_DATA_DIGEST_ERR             0x02
 
-/* NOP-Out may be used by an initiator as a "ping request" to verify
-   that a connection/session is still active and all its components are
-   operational. The NOP-In response is the "ping echo".
+/// iSCSI Reject reason packet data: SNACK Reject (original PDU can be resent).
+#define ISCSI_REJECT_REASON_SNACK_REJECT                0x03
 
-   A NOP-Out is also sent by an initiator in response to a NOP-In.
+/// iSCSI Reject reason packet data: Protocol Error (e.g., SNACK Request for a status that was already acknowledged). Original PDU can't be resent.
+#define ISCSI_REJECT_REASON_PROTOCOL_ERR                0x04
 
-   A NOP-Out may also be used to confirm a changed ExpStatSN if another
-   PDU will not be available for a long time.
+/// iSCSI Reject reason packet data: Command not supported (original PDU can't be resent).
+#define ISCSI_REJECT_REASON_COMMAND_NOT_SUPPORTED       0x05
 
-   Upon receipt of a NOP-In with the Target Transfer Tag set to a valid
-   value (not the reserved value 0xffffffff), the initiator MUST respond
-   with a NOP-Out. In this case, the NOP-Out Target Transfer Tag MUST
-   contain a copy of the NOP-In Target Transfer Tag. The initiator
+/// iSCSI Reject reason packet data: Immediate command reject - too many immediate commands (original PDU can be resent).
+#define ISCSI_REJECT_REASON_TOO_MANY_IMMEDIATE_COMMANDS 0x06
 
-   SHOULD NOT send a NOP-Out in response to any other received NOP-In,
-   in order to avoid lengthy sequences of NOP-In and NOP-Out PDUs sent
-   in response to each other.
-*/
+/// iSCSI Reject reason packet data: Task in progress (original PDU can't be resent).
+#define ISCSI_REJECT_REASON_TASK_IN_PROGRESS            0x07
+
+/// iSCSI Reject reason packet data: Invalid data ack (original PDU can't be resent).
+#define ISCSI_REJECT_REASON_INVALID_DATA_ACK            0x08
+
+/**
+ * @brief iSCSI Reject reason packet data: Invalid PDU field, original PDU can't be resent.
+ *
+ * A target should use this reason code for all invalid values
+ * of PDU fields that are meant to describe a task, a response,
+ * or a data transfer. Some examples are invalid TTT/ITT,
+ * buffer offset, LUN qualifying a TTT, and an invalid sequence
+ * number in a SNACK.
+ */
+#define ISCSI_REJECT_REASON_INVALID_PDU_FIELD           0x09
+
+/// iSCSI Reject reason packet data: Long op reject - Can't generate Target Transfer Tag - out of resources. Original PDU can be resent later.
+#define ISCSI_REJECT_REASON_OUT_OF_RESOURCES            0x0A
+
+/**
+ * @brief iSCSI Reject reason packet data: Deprecated; MUST NOT be used.
+ *
+ * Reason code 0x0B is deprecated and MUST NOT be used by
+ * implementations. An implementation receiving reason code
+ * 0x0B MUST treat it as a negotiation failure that terminates
+ * the Login Phase and the TCP connection.
+ */
+#define ISCSI_REJECT_REASON_DEPRECATED                  0x0B
+
+/// iSCSI Reject reason packet data: Waiting for Logout, original PDU can't be resent.
+#define ISCSI_REJECT_REASON_WAITING_FOR_LOGOUT          0x0C
+
+/**
+ * @brief iSCSI Reject packet data.
+ *
+ * This structure will be received or sent, if an iSCSI
+ * packet was rejected or has been rejected for some reason.
+ */
+typedef struct __attribute__((packed)) iscsi_reject_packet {
+    /// Always 0x3F according to iSCSI specification.
+    uint8_t opcode;
+
+    /// Reserved for future usage (must be always 0x80 for now).
+    int8_t flags;
+
+    /**
+     * @brief Reject reason.
+     *
+     * In all the cases in which a pre-instantiated SCSI task is terminated
+     * because of the reject, the target MUST issue a proper SCSI command
+     * response with CHECK CONDITION. In these cases in which a status for
+     * the SCSI task was already sent before the reject, no additional
+     * status is required. If the error is detected while data from the
+     * initiator is still expected (i.e., the command PDU did not contain
+     * all the data and the target has not received a Data-Out PDU with the
+     * Final bit set to 1 for the unsolicited data, if any, and all
+     * outstanding R2Ts, if any), the target MUST wait until it receives
+     * the last expected Data-Out PDUs with the F bit set to 1 before
+     * sending the Response PDU.
+     */
+    uint8_t reason;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint8_t reserved;
+
+    /// TotalAHSLength.
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength.
+    uint8_t ds_len[3];
+
+    /// Reserved for future usage, always MUST be 0.
+    uint64_t reserved2;
+
+    /// Always 0xFFFFFFFF for now.
+    uint32_t tag;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved3;
+
+    /**
+     * @brief StatSN.
+     *
+     * This field carries its usual value and is not related to the
+     * rejected command. The StatSN is advanced after a Reject.
+     */
+    uint32_t stat_sn;
+
+    /**
+     * @brief ExpCmdSN.
+     *
+     * This field carries its usual value and is not related to the
+     * rejected command.
+     */
+    uint32_t exp_cmd_sn;
+
+    /**
+     * @brief MaxCmdSN.
+     *
+     * This field carries its usual value and is not related to the
+     * rejected command.
+     */
+    uint32_t max_cmd_sn;
+
+    /**
+     * @brief DataSN / Ready To Transfer Sequence Number (R2TSN) or Reserved.
+     *
+     * This field is only valid if the rejected PDU is a Data/R2T SNACK and
+     * the Reject reason code is "Protocol Error". The DataSN/R2TSN is the
+     * next Data/R2T sequence number that the target would send for the
+     * task, if any.
+     */
+    uint32_t data_r2tsn_sn;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved4[2];
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
+
+    /**
+     * @brief Complete Header of Bad PDU.
+     *
+     * The target returns the header (not including the digest) of the
+     * PDU in error as the data of the response.
+     */
+    iscsi_bhs_packet bad_pdu_hdr;
+
+    /// Vendor-specific data (if any).
+    uint8_t vendor_data[0];
+
+    /// Optional data digest.
+    iscsi_data_digest data_digest;
+} iscsi_reject_packet;
+
+/**
+ * @brief iSCSI NOP-Out packet data.
+ *
+ * NOP-Out may be used by an initiator as a "ping request" to verify
+ * that a connection/session is still active and all its components are
+ * operational. The NOP-In response is the "ping echo".
+ *
+ * A NOP-Out is also sent by an initiator in response to a NOP-In.
+ *
+ * A NOP-Out may also be used to confirm a changed ExpStatSN if another
+ * PDU will not be available for a long time.
+ *
+ * Upon receipt of a NOP-In with the Target Transfer Tag set to a valid
+ * value (not the reserved value 0xffffffff), the initiator MUST respond
+ * with a NOP-Out. In this case, the NOP-Out Target Transfer Tag MUST
+ * contain a copy of the NOP-In Target Transfer Tag. The initiator
+ *
+ * SHOULD NOT send a NOP-Out in response to any other received NOP-In,
+ * in order to avoid lengthy sequences of NOP-In and NOP-Out PDUs sent
+ * in response to each other.
+ */
 typedef struct __attribute__((packed)) iscsi_nop_out_packet {
-    uint8_t opcode; // Always 0x00 according to specification (see above)
-    uint8_t reserved[3]; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength
-    uint8_t ds_len[3]; // DataSegmentLength
-    uint64_t lun; // LUN or Reserved
-    uint32_t init_task_tag; // The NOP-Out MUST have the Initiator Task Tag set to a valid value
-                            // only if a response in the form of a NOP-In is requested (i.e., the
-                            // NOP-Out is used as a ping request). Otherwise, the Initiator Task
-                            // Tag MUST be set to 0xFFFFFFFF.
-                            // When a target receives the NOP-Out with a valid Initiator Task Tag,
-                            // it MUST respond with a NOP-In Response.
-                            // If the Initiator Task Tag contains 0xFFFFFFFF, the I bit MUST be set
-                            // to 1, and the CmdSN is not advanced after this PDU is sent
-    uint32_t target_xfer_tag; // The Target Transfer Tag is a target-assigned identifier for the
-                              // operation.
-                              // The NOP-Out MUST only have the Target Transfer Tag set if it is
-                              // issued in response to a NOP-In with a valid Target Transfer Tag. In
-                              // this case, it copies the Target Transfer Tag from the NOP-In PDU.
-                              // Otherwise, the Target Transfer Tag MUST be set to 0xFFFFFFFF.
-                              // When the Target Transfer Tag is set to a value other than 0xFFFFFFFF,
-                              // the LUN field MUST also be copied from the NOP-In
-    uint32_t cmd_sn; // CmdSN
-    uint32_t exp_stat_sn; // ExpStatSN
-    uint64_t reserved2[2]; // Reserved for future usage
-    struct iscsi_header_digest hdr_digest; // Optional header digest
-    struct iscsi_ds_cmd_data ds_ping_data; // DataSegment - Ping Data (optional)
-                                           // Ping data is reflected in the NOP-In Response. The length of the
-                                           // reflected data is limited to MaxRecvDataSegmentLength. The length of
-                                           // ping data is indicated by the DataSegmentLength. 0 is a valid value
-                                           // for the DataSegmentLength and indicates the absence of ping data
-    struct iscsi_data_digest data_digest; // Optional data digest
+    /// Always 0x00 according to iSCSI specification.
+    uint8_t opcode;
+
+    /// Reserved for future usage (must be always 0x80 for now).
+    int8_t flags;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint16_t reserved;
+
+    /// TotalAHSLength.
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength.
+    uint8_t ds_len[3];
+
+    /// LUN or Reserved.
+    uint64_t lun;
+
+    /**
+     * @brief Initiator Task Tag (ITT).
+     *
+     * The NOP-Out MUST have the Initiator Task Tag set to a valid value
+     * only if a response in the form of a NOP-In is requested (i.e., the
+     * NOP-Out is used as a ping request). Otherwise, the Initiator Task
+     * Tag MUST be set to 0xFFFFFFFF.\n
+     * When a target receives the NOP-Out with a valid Initiator Task Tag,
+     * it MUST respond with a NOP-In Response.\n
+     * If the Initiator Task Tag contains 0xFFFFFFFF, the I bit MUST be set
+     * to 1, and the CmdSN is not advanced after this PDU is sent.
+     */
+    uint32_t init_task_tag;
+
+    /**
+     * @brief Target Transfer Tag (TTT).
+     *
+     * The Target Transfer Tag is a target-assigned identifier for the
+     * operation.\n
+     * The NOP-Out MUST only have the Target Transfer Tag set if it is
+     * issued in response to a NOP-In with a valid Target Transfer Tag. In
+     * this case, it copies the Target Transfer Tag from the NOP-In PDU.\n
+     * Otherwise, the Target Transfer Tag MUST be set to 0xFFFFFFFF.\n
+     * When the Target Transfer Tag is set to a value other than 0xFFFFFFFF,
+     * the LUN field MUST also be copied from the NOP-In.
+     */
+    uint32_t target_xfer_tag;
+
+    /// CmdSN.
+    uint32_t cmd_sn;
+
+    /// ExpStatSN.
+    uint32_t exp_stat_sn;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint64_t reserved2[2];
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
+
+    /**
+     * @brief DataSegment - Ping Data (optional).
+     *
+     * Ping data is reflected in the NOP-In Response. The length of the
+     * reflected data is limited to MaxRecvDataSegmentLength. The length of
+     * ping data is indicated by the DataSegmentLength. 0 is a valid value
+     * for the DataSegmentLength and indicates the absence of ping data.
+     */
+    iscsi_ds_cmd_data ds_ping_data;
+
+    /// Optional data digest.
+    iscsi_data_digest data_digest;
 } iscsi_nop_out_packet;
 
-/*  NOP-In is sent by a target as either a response to a NOP-Out, a
-   "ping" to an initiator, or a means to carry a changed ExpCmdSN and/or
-   MaxCmdSN if another PDU will not be available for a long time (as
-   determined by the target).
-
-   When a target receives the NOP-Out with a valid Initiator Task Tag
-   (not the reserved value 0xFFFFFFFF), it MUST respond with a NOP-In
-   with the same Initiator Task Tag that was provided in the NOP-Out
-   request. It MUST also duplicate up to the first
-   MaxRecvDataSegmentLength bytes of the initiator-provided Ping Data.
-   For such a response, the Target Transfer Tag MUST be 0xFFFFFFFF. The
-
-   target SHOULD NOT send a NOP-In in response to any other received
-   NOP-Out in order to avoid lengthy sequences of NOP-In and NOP-Out
-   PDUs sent in response to each other.
-
-   Otherwise, when a target sends a NOP-In that is not a response to a
-   NOP-Out received from the initiator, the Initiator Task Tag MUST be
-   set to 0xFFFFFFFF, and the data segment MUST NOT contain any data
-   (DataSegmentLength MUST be 0).
-*/
 
+/**
+ * @brief iSCSI NOP-In packet data.
+ *
+ * NOP-In is sent by a target as either a response to a NOP-Out, a
+ * "ping" to an initiator, or a means to carry a changed ExpCmdSN and/or
+ * MaxCmdSN if another PDU will not be available for a long time (as
+ * determined by the target).
+ *
+ * When a target receives the NOP-Out with a valid Initiator Task Tag
+ * (not the reserved value 0xFFFFFFFF), it MUST respond with a NOP-In
+ * with the same Initiator Task Tag that was provided in the NOP-Out
+ * request. It MUST also duplicate up to the first
+ * MaxRecvDataSegmentLength bytes of the initiator-provided Ping Data.
+ * For such a response, the Target Transfer Tag MUST be 0xFFFFFFFF.
+ *
+ * The target SHOULD NOT send a NOP-In in response to any other received
+ * NOP-Out in order to avoid lengthy sequences of NOP-In and NOP-Out
+ * PDUs sent in response to each other.
+ *
+ * Otherwise, when a target sends a NOP-In that is not a response to a
+ * NOP-Out received from the initiator, the Initiator Task Tag MUST be
+ * set to 0xFFFFFFFF, and the data segment MUST NOT contain any data
+ * (DataSegmentLength MUST be 0).
+ */
 typedef struct __attribute__((packed)) iscsi_nop_in_packet {
-    uint8_t opcode; // Always 0x20 according to specification (see above)
-    uint8_t reserved[3]; // Reserved for future usage
-    uint8_t total_ahs_len; // TotalAHSLength
-    uint8_t ds_len[3]; // DataSegmentLength
-    uint64_t lun; // A LUN MUST be set to a correct value when the Target Transfer Tag is
-                  // valid (not the reserved value 0xFFFFFFFF)
-    uint32_t init_task_tag; // Initiator task tag or 0xFFFFFFFF
-    uint32_t target_xfer_tag; // If the target is responding to a NOP-Out, this field is set to the
-                              // reserved value 0xFFFFFFFF.
-                              // If the target is sending a NOP-In as a ping (intending to receive a
-                              // corresponding NOP-Out), this field is set to a valid value (not the
-                              // reserved value 0xFFFFFFFF).
-                              // If the target is initiating a NOP-In without wanting to receive a
-                              // corresponding NOP-Out, this field MUST hold the reserved value
-                              // 0xFFFFFFFF
-    uint32_t stat_sn; // The StatSN field will always contain the next StatSN. However, when
-                      // the Initiator Task Tag is set to 0xFFFFFFFF, the StatSN for the
-                      // connection is not advanced after this PDU is sent
+    /// Always 0x20 according to iSCSI specification.
+    uint8_t opcode;
+
+    /// Reserved for future usage (must be always 0x80 for now).
+    int8_t flags;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint16_t reserved;
+
+    /// TotalAHSLength
+    uint8_t total_ahs_len;
+
+    /// DataSegmentLength.
+    uint8_t ds_len[3];
+
+    /// A LUN MUST be set to a correct value when the Target Transfer Tag is valid (not the reserved value 0xFFFFFFFF).
+    uint64_t lun;
+
+    /// Initiator Task Tag (ITT) or 0xFFFFFFFF.
+    uint32_t init_task_tag;
+
+    /**
+     * @brief Target Transfer Tag (TTT).
+     *
+     * If the target is responding to a NOP-Out, this field is set to the
+     * reserved value 0xFFFFFFFF.\n
+     * If the target is sending a NOP-In as a ping (intending to receive a
+     * corresponding NOP-Out), this field is set to a valid value (not the
+     * reserved value 0xFFFFFFFF).\n
+     * If the target is initiating a NOP-In without wanting to receive a
+     * corresponding NOP-Out, this field MUST hold the reserved value
+     * 0xFFFFFFFF.
+     */
+    uint32_t target_xfer_tag;
+
+    /**
+     * @brief StatSN.
+     *
+     * The StatSN field will always contain the next StatSN. However, when
+     * the Initiator Task Tag is set to 0xFFFFFFFF, the StatSN for the
+     * connection is not advanced after this PDU is sent.
+     */
+    uint32_t stat_sn;
+
+    /// ExpCmdSN.
     uint32_t exp_cmd_sn; // ExpCmdSN
-    uint32_t max_cmd_sn; // MaxCmdSN
-    uint32_t reserved2[3]; // Reserved for future usage
-    struct iscsi_header_digest hdr_digest; // Optional header digest
-    struct iscsi_ds_cmd_data ds_ping_data; // DataSegment - Return Ping Data
-    struct iscsi_data_digest data_digest; // Optional data digest
+
+    /// MaxCmdSN.
+    uint32_t max_cmd_sn;
+
+    /// Reserved for future usage, always MUST be 0.
+    uint32_t reserved2[3];
+
+    /// Optional header digest.
+    iscsi_header_digest hdr_digest;
+
+    /// DataSegment - Return Ping Data.
+    iscsi_ds_cmd_data ds_ping_data;
+
+    /// Optional data digest.
+    iscsi_data_digest data_digest;
 } iscsi_nop_in_packet;
 
-#define ISCSI_VALIDATE_PACKET_RESULT_OK                         0L // Validation successful -> iSCSI packet recognized and compliance to protocol specification
-#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_NO_DATA             -1L // Validation failed -> No packet data specified
-#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_SIZE_TOO_SMALL      -2L // Validation failed -> Packet size smaller than smallest possible iSCSI packet
-#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_SIZE_MISMATCH       -3L // Validation failed -> Packet size doesn't match calculated lengths from BHS
-#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_UNSUPPORTED_VERSION -4L // Validation failed -> iSCSI protocol version not supported yet
-#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS      -5L // Validation failed -> Valid opcode but violates iSCSI protocol specification
-#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_INVALID_OPCODE      -6L // Validation failed -> Invalid opcode according to iSCSI protocol specification
-#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_CRC32C_HDR_DIGEST   -7L // Validation failed -> CRC32C check failed for header (BHS and/or AHS)
-#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_CRC32C_DATA_DIGEST  -8L // Validation failed -> CRC32C check failed for data segment
+
+/// iSCSI packet validation return code from iscsi_validate_packet function: Validation successful -> iSCSI packet recognized and compliance to protocol specification.
+#define ISCSI_VALIDATE_PACKET_RESULT_OK                         0L
+
+/// iSCSI packet validation return code from iscsi_validate_packet function: Validation failed -> No packet data specified.
+#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_NO_DATA             -1L
+
+/// iSCSI packet validation return code from iscsi_validate_packet function: Validation failed -> Packet size smaller than smallest possible iSCSI packet.
+#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_SIZE_TOO_SMALL      -2L
+
+/// iSCSI packet validation return code from iscsi_validate_packet function: Validation failed -> Packet size doesn't match calculated lengths from BHS.
+#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_SIZE_MISMATCH       -3L
+
+/// iSCSI packet validation return code from iscsi_validate_packet function: Validation failed -> iSCSI protocol version not supported yet.
+#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_UNSUPPORTED_VERSION -4L
+
+/// iSCSI packet validation return code from iscsi_validate_packet function: Validation failed -> Valid opcode but violates iSCSI protocol specification.
+#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_PROTOCOL_SPECS      -5L
+
+/// iSCSI packet validation return code from iscsi_validate_packet function: Validation failed -> Invalid opcode according to iSCSI protocol specification.
+#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_INVALID_OPCODE      -6L
+
+/// iSCSI packet validation return code from iscsi_validate_packet function: Validation failed -> CRC32C check failed for header (BHS and/or AHS).
+#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_CRC32C_HDR_DIGEST   -7L
+
+/// iSCSI packet validation return code from iscsi_validate_packet function: Validation failed -> CRC32C check failed for data segment.
+#define ISCSI_VALIDATE_PACKET_RESULT_ERROR_CRC32C_DATA_DIGEST  -8L
+
 
 iscsi_bhs_packet *iscsi_create_packet(); // Allocate and initialize an iSCSI BHS packet
 void iscsi_destroy_packet(iscsi_bhs_packet *packet_data); // Free resources allocated by iscsi_create_packet
@@ -2868,94 +5558,119 @@ void iscsi_calc_header_digest(const iscsi_bhs_packet *packet_data); // Calculate
 int iscsi_validate_header_digest(const iscsi_bhs_packet *packet_data); // Validates a stored iSCSI header digest (CRC32C) with actual header data
 void iscsi_calc_data_digest(const iscsi_bhs_packet *packet_data, const int header_digest_size); // Calculate iSCSI data digest (CRC32C)
 int iscsi_validate_data_digest(const iscsi_bhs_packet *packet_data, const int header_digest_size); // Validates a stored iSCSI data digest (CRC32C) with actual DataSegment
-static int iscsi_validate_text_key_value_pair(const uint8_t *packet_data, const uint32_t len); // Validates a single text key / value pair according to iSCSI specs
-static int iscsi_validate_key_value_pairs(const uint8_t *packet_data, uint len); // Validates all text key / value pairs according to iSCSI specs
 int iscsi_validate_packet(const struct iscsi_bhs_packet *packet_data, const uint32_t len, const int header_digest_size, const int data_digest_size); // Check if valid iSCSI packet and validate if necessarily
 
-#define ISCSI_TEXT_KEY_MAX_LEN 63UL // Maximum length of a key according to iSCSI specs
 
-#define ISCSI_TEXT_VALUE_MAX_SIMPLE_LEN 255UL  // Maximum length of value for a simple key type
-#define ISCSI_TEXT_VALUE_MAX_LEN        8192UL // Maximum length of value for a normal key
+/// Maximum length of a key according to iSCSI specifications.
+#define ISCSI_TEXT_KEY_MAX_LEN 63UL
+
+/// Maximum length of value for a simple key type.
+#define ISCSI_TEXT_VALUE_MAX_SIMPLE_LEN 255UL
+
+/// Maximum length of value for a normal key.
+#define ISCSI_TEXT_VALUE_MAX_LEN        8192UL
+
+/// iSCSI text key=value pair type: Invalid.
+#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_INVALID         -1L
 
-#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_INVALID         -1L // Invalid
-#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_UNSPECIFIED      0L // Unspecified type
-#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_LIST             1L // List
-#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_NUM_MIN          2L // Numerical minimum
-#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_NUM_MAX          3L // Numerical maximum
-#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_NUM_DECLARATIVE  4L // Numerical declarative
-#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_DECLARATIVE      5L // Declarative
-#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_BOOL_OR          6L // Boolean OR
-#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_BOOL_AND         7L // Boolean AND
+/// iSCSI text key=value pair type: Unspecified type.
+#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_UNSPECIFIED      0L
 
+/// iSCSI text key=value pair type: List.
+#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_LIST             1L
+
+/// iSCSI text key=value pair type: Numerical minimum.
+#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_NUM_MIN          2L
+
+/// iSCSI text key=value pair type: Numerical maximum.
+#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_NUM_MAX          3L
+
+/// iSCSI text key=value pair type: Numerical declarative.
+#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_NUM_DECLARATIVE  4L
+
+/// iSCSI text key=value pair type: Declarative.
+#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_DECLARATIVE      5L
+
+/// iSCSI text key=value pair type: Boolean OR.
+#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_BOOL_OR          6L
+
+/// iSCSI text key=value pair type: Boolean AND.
+#define ISCSI_TEXT_KEY_VALUE_PAIR_TYPE_BOOL_AND         7L
+
+
+/**
+ * @brief iSCSI Text / Login extracted key=value pair.
+ *
+ * This structure is used for accessing key and value
+ * pairs which have been extracted from either the
+ * Text or Login packet data.
+ */
 typedef struct iscsi_key_value_pair {
-	int type; // Type of pair (see above)
+    /// Type of key and value pair.
+	int type;
+
+    /// State index.
 	int state_index;
-	uint8_t *value; // Value of key
+
+    /// Value of the key which is stored in the hash map.
+	uint8_t *value;
 } iscsi_key_value_pair;
 
+/**
+ * @brief iSCSI Text / Login key=value packet data construction helper.
+ *
+ * This structure is used to store the key=value plus NUL terminator
+ * pairs for sending as DataSegment packet data to the client.
+ */
 typedef struct iscsi_key_value_pair_packet {
-    uint8_t *buf; // Current text buffer containing multiple zeroes
-    uint len; // Current length of buffer including final zero terminator
+    /// Current text buffer containing multiple key=value + NUL terminator pairs.
+    uint8_t *buf;
+
+    /// Current length of buffer including final NUL terminator without iSCSI zero padding.
+    uint len;
 } iscsi_key_value_pair_packet;
 
-static int iscsi_parse_text_key_value_pair(iscsi_hashmap *pairs, const uint8_t *packet_data, const uint32_t len); // Extracts a single text key / value pairs out of an iSCSI packet into a hash map
-int iscsi_parse_key_value_pairs(iscsi_hashmap **pairs, const uint8_t *packet_data, uint len, int cbit, uint8_t **partial_pair); // Extracts all text key / value pairs out of an iSCSI packet into a hash map
+int iscsi_parse_key_value_pairs(iscsi_hashmap *pairs, const uint8_t *packet_data, uint len, int cbit, uint8_t **partial_pair); // Extracts all text key / value pairs out of an iSCSI packet into a hash map
 int iscsi_create_key_value_pair_packet_callback(uint8_t *key, const size_t key_size, uint8_t *value, uint8_t *user_data); // Creates a single partial iSCSI packet stream out of a single text key and value pair
 iscsi_key_value_pair_packet *iscsi_create_key_value_pairs_packet(const iscsi_hashmap *pairs); // Creates a properly aligned iSCSI packet DataSegment out of a hash map containing text key and value pairs
 
+/**
+ * @brief iSCSI incoming connection.
+ *
+ * This structure is used for maintaining incoming iSCSI
+ * connections. Negiotiated text key=value pairs are
+ * stored here, status of the connection, session
+ * and iSCSI portals.
+ */
 typedef struct iscsi_connection {
-    iscsi_hashmap *key_value_pairs; // Hash map containing text key / value pairs associated to this connection
-    int header_digest; // iSCSI connection contains a header digest (CRC32), must be 0 or 4 for now
-    int data_digest; // iSCSI connection contains a data digest (CRC32), must be 0 or 4 for now
-    uint8_t opcode; // Always 0x03 according to specification (see above)
-    int8_t flags; // Login request flags (see above)
-    uint8_t version_max; // Version-max indicates the maximum version number supported.
-                         // All Login Requests within the Login Phase MUST carry the same
-                         // Version-max. Currently, this is always 0
-                         // The target MUST use the value presented with the first Login Request.
-    uint8_t version_min; // All Login Requests within the Login Phase MUST carry the same
-                         // Version-min. The target MUST use the value presented with the first
-                         // Login Request. Always 0 for now
-    struct iscsi_isid isid; // ISID (see above for declaration)
-    uint16_t tsih; // The TSIH must be set in the first Login Request. The reserved value
-                   // 0 MUST be used on the first connection for a new session. Otherwise,
-                   // the TSIH sent by the target at the conclusion of the successful login
-                   // of the first connection for this session MUST be used. The TSIH
-                   // identifies to the target the associated existing session for this new
-                   // connection.
-                   // All Login Requests within a Login Phase MUST carry the same TSIH.
-                   // The target MUST check the value presented with the first Login
-                   // Request
-    uint32_t init_task_tag; // Initiator task tag
-    uint16_t cid; // Connection ID. The CID provides a unique ID for this connection within the session.
-                  // All Login Requests within the Login Phase MUST carry the same CID.
-                  // The target MUST use the value presented with the first Login Request.
-                  // A Login Request with a non-zero TSIH and a CID equal to that of an
-                  // existing connection implies a logout of the connection followed by a
-                  // login
-    uint32_t cmd_sn; // The CmdSN is either the initial command sequence number of a session
-                     // (for the first Login Request of a session - the "leading" login) or
-                     // the command sequence number in the command stream if the login is for
-                     // a new connection in an existing session.
-                     // Examples:
-                     // - Login on a leading connection: If the leading login carries the
-                     //   CmdSN 123, all other Login Requests in the same Login Phase carry
-                     //   the CmdSN 123, and the first non-immediate command in the Full
-                     //   Feature Phase also carries the CmdSN 123.
-                     // - Login on other than a leading connection: If the current CmdSN at
-                     //   the time the first login on the connection is issued is 500, then
-                     //   that PDU carries CmdSN=500. Subsequent Login Requests that are
-                     //   needed to complete this Login Phase may carry a CmdSN higher than
-                     //   500 if non-immediate requests that were issued on other connections
-                     //   in the same session advance the CmdSN.
-                     // If the Login Request is a leading Login Request, the target MUST use
-                     // the value presented in the CmdSN as the target value for the
-                     // ExpCmdSN
-    uint32_t exp_stat_sn; // For the first Login Request on a connection, this is the ExpStatSN
-                          // for the old connection, and this field is only valid if the Login
-                          // Request restarts a connection
-                          // For subsequent Login Requests, it is used to acknowledge the Login
-                          // Responses with their increasing StatSN values
+    /// Hash map containing text key / value pairs associated to this connection.
+    iscsi_hashmap *key_value_pairs;
+
+    /// iSCSI connection contains a header digest (CRC32), always MUST be 0 or 4 for now.
+    int header_digest;
+
+    /// iSCSI connection contains a data digest (CRC32), always MUST be 0 or 4 for now.
+    int data_digest;
+
+    int8_t flags;
+
+    /// Initiator Session ID (ISID).
+    iscsi_isid isid;
+
+    /// Target Session Identifying Handle (TSIH).
+    uint16_t tsih;
+
+    /// Initiator Task Tag (ITT).
+    uint32_t init_task_tag;
+
+    /// Connection ID (CID).
+    uint16_t cid;
+
+    /// CmdSN.
+    uint32_t cmd_sn;
+
+    /// ExpStatSN.
+    uint32_t exp_stat_sn;
 } iscsi_connection;
 
 iscsi_connection *iscsi_connection_create(const iscsi_login_req_packet *login_req_pkt); // Creates data structure for an iSCSI connection request