First draft of iSCSI protocol support. Is capable of retrieving disk

blocks.

2 files changed, 494 insertions, 0 deletions

diff --git a/src/include/gpxe/iscsi.h b/src/include/gpxe/iscsi.h
new file mode 100644
index 000000000..639da5e57
--- /dev/null
+++ b/src/include/gpxe/iscsi.h
@@ -0,0 +1,460 @@
+#ifndef _ISCSI_H
+#define _ISCSI_H
+
+/** @file
+ *
+ * iSCSI protocol
+ *
+ */
+
+#include <stdint.h>
+#include <gpxe/tcp.h>
+#include <gpxe/scsi.h>
+
+/**
+ * iSCSI segment lengths
+ *
+ * iSCSI uses an icky structure with one one-byte field (a dword
+ * count) and one three-byte field (a byte count).  This structure,
+ * and the accompanying macros, relieve some of the pain.
+ */
+union iscsi_segment_lengths {
+	struct {
+		/** The AHS length (measured in dwords) */
+		uint8_t ahs_len;
+		/** The data length (measured in bytes), in network
+		 * byte order
+		 */
+		uint8_t data_len[3];
+	} bytes;
+	/** Ths data length (measured in bytes), in network byte
+	 * order, with ahs_len as the first byte.
+	 */
+	uint32_t ahs_and_data_len;
+};
+
+/** The length of the additional header segment, in dwords */
+#define ISCSI_AHS_LEN( segment_lengths ) \
+	( (segment_lengths).bytes.ahs_len )
+
+/** The length of the data segment, in bytes, excluding any padding */
+#define ISCSI_DATA_LEN( segment_lengths ) \
+	( ntohl ( (segment_lengths).ahs_and_data_len ) & 0xffffff )
+
+/** The padding of the data segment, in bytes */
+#define ISCSI_DATA_PAD_LEN( segment_lengths ) \
+	( ( 0 - (segment_lengths).bytes.data_len[2] ) & 0x03 )
+
+/** Set additional header and data segment lengths */
+#define ISCSI_SET_LENGTHS( segment_lengths, ahs_len, data_len ) do {	\
+	(segment_lengths).ahs_and_data_len =				\
+		htonl ( data_len | ( ahs_len << 24 ) );			\
+	} while ( 0 )
+
+/**
+ * iSCSI basic header segment common fields
+ *
+ */
+struct iscsi_bhs_common {
+	/** Opcode */
+	uint8_t opcode;
+	/** Flags */
+	uint8_t flags;
+	/** Fields specific to the PDU type */
+	uint8_t other_a[2];
+	/** Segment lengths */
+	union iscsi_segment_lengths lengths;
+	/** Fields specific to the PDU type */
+	uint8_t other_b[8];
+	/** Initiator Task Tag */
+	uint32_t itt;
+	/** Fields specific to the PDU type */
+	uint8_t other_c[28];
+};
+
+/** Opcode mask */
+#define ISCSI_OPCODE_MASK 0x3f
+
+/** Immediate delivery */
+#define ISCSI_FLAG_IMMEDIATE 0x40
+
+/** Final PDU of a sequence */
+#define ISCSI_FLAG_FINAL 0x80
+
+/**
+ * iSCSI login request basic header segment
+ *
+ */
+struct iscsi_bhs_login_request {
+	/** Opcode */
+	uint8_t opcode;
+	/** Flags */
+	uint8_t flags;
+	/** Maximum supported version number */
+	uint8_t version_max;
+	/** Minimum supported version number */
+	uint8_t version_min;
+	/** Segment lengths */
+	union iscsi_segment_lengths lengths;
+	/** Initiator session ID (IANA format) enterprise number and flags */
+	uint32_t isid_iana_en;
+	/** Initiator session ID (IANA format) qualifier */
+	uint16_t isid_iana_qual;
+	/** Target session identifying handle */
+	uint16_t tsih;
+	/** Initiator Task Tag */
+	uint32_t itt;
+	/** Connection ID */
+	uint16_t cid;
+	/** Reserved */
+	uint16_t reserved_a;
+	/** Command sequence number */
+	uint32_t cmdsn;
+	/** Expected status sequence number */
+	uint32_t expstatsn;
+	/** Reserved */
+	uint8_t reserved_b[16];
+};
+
+/** Login request opcode */
+#define ISCSI_OPCODE_LOGIN_REQUEST 0x03
+
+/** Willingness to transition to next stage */
+#define ISCSI_LOGIN_FLAG_TRANSITION 0x80
+
+/** Key=value pairs continued in subsequent request */
+#define ISCSI_LOGIN_FLAG_CONTINUE 0x40
+
+/* Current stage values and mask */
+#define ISCSI_LOGIN_CSG_MASK 0x0c
+#define ISCSI_LOGIN_CSG_SECURITY_NEGOTIATION 0x00
+#define ISCSI_LOGIN_CSG_OPERATIONAL_NEGOTIATION 0x04
+#define ISCSI_LOGIN_CSG_FULL_FEATURE_PHASE 0x0c
+
+/* Next stage values and mask */
+#define ISCSI_LOGIN_NSG_MASK 0x03
+#define ISCSI_LOGIN_NSG_SECURITY_NEGOTIATION 0x00
+#define ISCSI_LOGIN_NSG_OPERATIONAL_NEGOTIATION 0x01
+#define ISCSI_LOGIN_NSG_FULL_FEATURE_PHASE 0x03
+
+/** ISID IANA format marker */
+#define ISCSI_ISID_IANA 0x40000000
+
+/** Fen Systems Ltd. IANA enterprise number
+ *
+ * Permission is hereby granted to use Fen Systems Ltd.'s IANA
+ * enterprise number with this iSCSI implementation.
+ */
+#define IANA_EN_FEN_SYSTEMS 10019
+
+/**
+ * iSCSI login response basic header segment
+ *
+ */
+struct iscsi_bhs_login_response {
+	/** Opcode */
+	uint8_t opcode;
+	/** Flags */
+	uint8_t flags;
+	/** Maximum supported version number */
+	uint8_t version_max;
+	/** Minimum supported version number */
+	uint8_t version_min;
+	/** Segment lengths */
+	union iscsi_segment_lengths lengths;
+	/** Initiator session ID (IANA format) enterprise number and flags */
+	uint32_t isid_iana_en;
+	/** Initiator session ID (IANA format) qualifier */
+	uint16_t isid_iana_qual;
+	/** Target session identifying handle */
+	uint16_t tsih;
+	/** Initiator Task Tag */
+	uint32_t itt;
+	/** Reserved */
+	uint32_t reserved_a;
+	/** Status sequence number */
+	uint32_t statsn;
+	/** Expected command sequence number */
+	uint32_t expcmdsn;
+	/** Maximum command sequence number */
+	uint32_t maxcmdsn;
+	/** Status class */
+	uint8_t status_class;
+	/** Status detail */
+	uint8_t status_detail;
+	/** Reserved */
+	uint8_t reserved_b[10];
+};
+
+/** Login response opcode */
+#define ISCSI_OPCODE_LOGIN_RESPONSE 0x23
+
+/**
+ * iSCSI SCSI command basic header segment
+ *
+ */
+struct iscsi_bhs_scsi_command {
+	/** Opcode */
+	uint8_t opcode;
+	/** Flags */
+	uint8_t flags;
+	/** Reserved */
+	uint16_t reserved_a;
+	/** Segment lengths */
+	union iscsi_segment_lengths lengths;
+	/** SCSI Logical Unit Number */
+	uint8_t lun[8];
+	/** Initiator Task Tag */
+	uint32_t itt;
+	/** Expected data transfer length */
+	uint32_t exp_len;
+	/** Command sequence number */
+	uint32_t cmdsn;
+	/** Expected status sequence number */
+	uint32_t expstatsn;
+	/** SCSI Command Descriptor Block (CDB) */
+	union scsi_cdb cdb;
+};
+
+/** SCSI command opcode */
+#define ISCSI_OPCODE_SCSI_COMMAND 0x01
+
+/** Command will read data */
+#define ISCSI_COMMAND_FLAG_READ 0x40
+
+/** Command will write data */
+#define ISCSI_COMMAND_FLAG_WRITE 0x20
+
+/* Task attributes */
+#define ISCSI_COMMAND_ATTR_UNTAGGED 0x00
+#define ISCSI_COMMAND_ATTR_SIMPLE 0x01
+#define ISCSI_COMMAND_ATTR_ORDERED 0x02
+#define ISCSI_COMMAND_ATTR_HEAD_OF_QUEUE 0x03
+#define ISCSI_COMMAND_ATTR_ACA 0x04
+
+/**
+ * iSCSI SCSI response basic header segment
+ *
+ */
+struct iscsi_bhs_scsi_response {
+	/** Opcode */
+	uint8_t opcode;
+	/** Flags */
+	uint8_t flags;
+	/** Response code */
+	uint8_t response;
+	/** SCSI status code */
+	uint8_t status;
+	/** Segment lengths */
+	union iscsi_segment_lengths lengths;
+	/** Reserved */
+	uint8_t reserved_a[8];
+	/** Initiator Task Tag */
+	uint32_t itt;
+	/** SNACK tag */
+	uint32_t snack;
+	/** Status sequence number */
+	uint32_t statsn;
+	/** Expected command sequence number */
+	uint32_t expcmdsn;
+	/** Maximum command sequence number */
+	uint32_t maxcmdsn;
+	/** Expected data sequence number */
+	uint32_t expdatasn;
+	/** Reserved */
+	uint8_t reserved_b[8];
+};
+
+/** SCSI response opcode */
+#define ISCSI_OPCODE_SCSI_RESPONSE 0x21
+
+/** SCSI command completed at target */
+#define ISCSI_RESPONSE_COMMAND_COMPLETE 0x00
+
+/** SCSI target failure */
+#define ISCSI_RESPONSE_TARGET_FAILURE 0x01
+
+/**
+ * iSCSI data in basic header segment
+ *
+ */
+struct iscsi_bhs_data_in {
+	/** Opcode */
+	uint8_t opcode;
+	/** Flags */
+	uint8_t flags;
+	/** Reserved */
+	uint8_t reserved_a;
+	/** SCSI status code */
+	uint8_t status;
+	/** Segment lengths */
+	union iscsi_segment_lengths lengths;
+	/** Logical Unit Number */
+	uint8_t lun[8];
+	/** Initiator Task Tag */
+	uint32_t itt;
+	/** Target Transfer Tag */
+	uint32_t ttt;
+	/** Status sequence number */
+	uint32_t statsn;
+	/** Expected command sequence number */
+	uint32_t expcmdsn;
+	/** Maximum command sequence number */
+	uint32_t maxcmdsn;
+	/** Data sequence number */
+	uint32_t datasn;
+	/** Buffer offset */
+	uint32_t offset;
+	/** Residual count */
+	uint32_t residual_count;
+};
+
+/** Data in opcode */
+#define ISCSI_OPCODE_DATA_IN 0x25
+
+/** Data requires acknowledgement */
+#define ISCSI_DATA_FLAG_ACKNOWLEDGE 0x40
+
+/** Data overflow occurred */
+#define ISCSI_DATA_FLAG_OVERFLOW 0x04
+
+/** Data underflow occurred */
+#define ISCSI_DATA_FLAG_UNDERFLOW 0x02
+
+/** SCSI status code and verflow/underflow flags are valid */
+#define ISCSI_DATA_FLAG_STATUS 0x01
+
+/**
+ * An iSCSI basic header segment
+ */
+union iscsi_bhs {
+	struct iscsi_bhs_common common;
+	struct iscsi_bhs_login_request login_request;
+	struct iscsi_bhs_login_response login_response;
+	struct iscsi_bhs_scsi_command scsi_command;
+	struct iscsi_bhs_scsi_response scsi_response;
+	struct iscsi_bhs_data_in data_in;
+	unsigned char bytes[ sizeof ( struct iscsi_bhs_common ) ];
+};
+
+/** State */
+enum iscsi_state {
+	/** In the process of logging in */
+	ISCSI_STATE_FAILED = -1,
+	ISCSI_STATE_NOT_CONNECTED = 0,
+	ISCSI_STATE_IDLE,
+	ISCSI_STATE_LOGGING_IN,
+	ISCSI_STATE_READING_DATA,
+};
+
+/** State of an iSCSI TX engine */
+enum iscsi_tx_state {
+	/** Nothing to send */
+	ISCSI_TX_IDLE = 0,
+	/** Sending the basic header segment */
+	ISCSI_TX_BHS,
+	/** Sending the additional header segment */
+	ISCSI_TX_AHS,
+	/** Sending the data segment */
+	ISCSI_TX_DATA,
+	/** Sending the data segment padding */
+	ISCSI_TX_DATA_PADDING,
+};
+
+/** State of an iSCSI RX engine */
+enum iscsi_rx_state {
+	/** Receiving the basic header segment */
+	ISCSI_RX_BHS = 0,
+	/** Receiving the additional header segment */
+	ISCSI_RX_AHS,
+	/** Receiving the data segment */
+	ISCSI_RX_DATA,
+	/** Receiving the data segment padding */
+	ISCSI_RX_DATA_PADDING,
+};
+
+/** An iSCSI session */
+struct iscsi_session {
+	/** TCP connection for this session */
+	struct tcp_connection tcp;
+
+	/** Initiator IQN */
+	const char *initiator;
+	/** Target IQN */
+	const char *target;
+
+	/** Block size in bytes */
+	size_t block_size;
+	/** Starting block number of the current data transfer */
+	unsigned long block_start;
+	/** Block count of the current data transfer */
+	unsigned long block_count;
+	/** Block read callback function
+	 *
+	 * Note that this may be called several times, since it is
+	 * called per-packet rather than per-block.
+	 */
+	void ( * block_read_callback ) ( void *private, const void *data,
+					 unsigned long offset, size_t len );
+	/** Block read callback private data
+	 *
+	 * This is passed to block_read_callback()
+	 */
+	void *block_read_private;
+
+	/** State of the session */
+	enum iscsi_state state;
+	/** Target session identifying handle
+	 *
+	 * This is assigned by the target when we first log in, and
+	 * must be reused on subsequent login attempts.
+	 */
+	uint16_t tsih;
+
+	/** Initiator task tag
+	 *
+	 * This is the tag of the current command.  It is incremented
+	 * whenever a final response PDU is received.
+	 */
+	uint32_t itt;
+	/** Command sequence number
+	 *
+	 * This is the sequence number of the current command, used to
+	 * fill out the CmdSN field in iSCSI request PDUs.  It is
+	 * updated with the value of the ExpCmdSN field whenever we
+	 * receive an iSCSI response PDU containing such a field.
+	 */
+	uint32_t cmdsn;
+	/** Status sequence number
+	 *
+	 * This is the most recent status sequence number present in
+	 * the StatSN field of an iSCSI response PDU containing such a
+	 * field.  Whenever we send an iSCSI request PDU, we fill out
+	 * the ExpStatSN field with this value plus one.
+	 */
+	uint32_t statsn;
+	
+	/** Basic header segment for current TX PDU */
+	union iscsi_bhs tx_bhs;
+	/** State of the TX engine */
+	enum iscsi_tx_state tx_state;
+	/** Byte offset within the current TX state */
+	size_t tx_offset;
+
+	/** Basic header segment for current RX PDU */
+	union iscsi_bhs rx_bhs;
+	/** State of the RX engine */
+	enum iscsi_rx_state rx_state;
+	/** Byte offset within the current RX state */
+	size_t rx_offset;
+};
+
+static inline int iscsi_busy ( struct iscsi_session *iscsi ) {
+	return ( iscsi->state > ISCSI_STATE_IDLE );
+}
+
+static inline int iscsi_error ( struct iscsi_session *iscsi ) {
+	return ( iscsi->state == ISCSI_STATE_FAILED );
+}
+
+#endif /* _ISCSI_H */
diff --git a/src/include/gpxe/scsi.h b/src/include/gpxe/scsi.h
new file mode 100644
index 000000000..05f9010ce
--- /dev/null
+++ b/src/include/gpxe/scsi.h
@@ -0,0 +1,34 @@
+#ifndef _SCSI_H
+#define _SCSI_H
+
+#include <stdint.h>
+
+struct scsi_cdb_read_10 {
+	/** Opcode */
+	uint8_t opcode;
+	/** Flags */
+	uint8_t flags;
+	/** Start address
+	 *
+	 * This is a logical block number, in big-endian order.
+	 */
+	uint32_t lba;
+	/** Group number */
+	uint8_t group;
+	/** Transfer length
+	 *
+	 * This is a logical block count.
+	 */
+	uint16_t len;
+	/** Control byte */
+	uint8_t control;
+} __attribute__ (( packed ));
+
+#define SCSI_OPCODE_READ_10 0x28
+
+union scsi_cdb {
+	struct scsi_cdb_read_10 read_10;
+	char bytes[16];
+};
+
+#endif /* _SCSI_H */