#include <stddef.h>
#include <string.h>
#include <vsprintf.h>
#include <errno.h>
#include <assert.h>
#include <byteswap.h>
#include <gpxe/scsi.h>
#include <gpxe/process.h>
#include <gpxe/iscsi.h>
/** @file
*
* iSCSI protocol
*
*/
static void iscsi_start_tx ( struct iscsi_session *iscsi );
/****************************************************************************
*
* iSCSI SCSI command issuing
*
*/
/**
* Build iSCSI SCSI command BHS
*
* @v iscsi iSCSI session
*/
static void iscsi_start_command ( struct iscsi_session *iscsi ) {
struct iscsi_bhs_scsi_command *command = &iscsi->tx_bhs.scsi_command;
assert ( ! ( iscsi->command->data_in && iscsi->command->data_out ) );
/* Construct BHS and initiate transmission */
iscsi_start_tx ( iscsi );
command->opcode = ISCSI_OPCODE_SCSI_COMMAND;
command->flags = ( ISCSI_FLAG_FINAL |
ISCSI_COMMAND_ATTR_SIMPLE );
if ( iscsi->command->data_in )
command->flags |= ISCSI_COMMAND_FLAG_READ;
if ( iscsi->command->data_out )
command->flags |= ISCSI_COMMAND_FLAG_WRITE;
ISCSI_SET_LENGTHS ( command->lengths, 0, iscsi->command->data_out_len);
command->lun = iscsi->lun;
command->itt = htonl ( iscsi->itt );
command->exp_len = htonl ( iscsi->command->data_in_len );
memcpy ( &command->cdb, &iscsi->command->cdb, sizeof ( command->cdb ));
}
/**
* Send iSCSI SCSI command data
*
* @v iscsi iSCSI session
*/
static void iscsi_tx_command ( struct iscsi_session *iscsi ) {
tcp_send ( &iscsi->tcp, iscsi->command->data_out + iscsi->tx_offset,
iscsi->command->data_out_len - iscsi->tx_offset );
}
/**
* Receive data segment of an iSCSI data-in PDU
*
* @v iscsi iSCSI session
* @v data Received data
* @v len Length of received data
* @v remaining Data remaining after this data
*
*/
static void iscsi_rx_data_in ( struct iscsi_session *iscsi, void *data,
size_t len, size_t remaining ) {
struct iscsi_bhs_data_in *data_in = &iscsi->rx_bhs.data_in;
unsigned long offset;
/* Copy data to data-in buffer */
offset = ntohl ( data_in->offset ) + iscsi->rx_offset;
assert ( iscsi->command != NULL );
assert ( iscsi->command->data_in != NULL );
assert ( ( offset + len ) <= iscsi->command->data_in_len );
memcpy ( ( iscsi->command->data_in + offset ), data, len );
/* If this is the end, flag as complete */
if ( ( data_in->flags & ISCSI_FLAG_FINAL ) && ( remaining == 0 ) )
iscsi->status |= ISCSI_STATUS_DONE;
}
/****************************************************************************
*
* iSCSI login
*
*/
/**
* Build iSCSI login request strings
*
* @v iscsi iSCSI session
*
* These are the initial set of strings sent in the first login
* request PDU.
*/
static int iscsi_build_login_request_strings ( struct iscsi_session *iscsi,
void *data, size_t len ) {
return snprintf ( data, len,
"InitiatorName=%s%c"
"TargetName=%s%c"
"MaxRecvDataSegmentLength=512%c"
"SessionType=Normal%c"
"DataDigest=None%c"
"HeaderDigest=None%c",
iscsi->initiator, 0, iscsi->target, 0,
0, 0, 0, 0 );
}
/**
* Build iSCSI login request BHS
*
* @v iscsi iSCSI session
* @v first Login request is the first request of a session
*/
static void iscsi_start_login ( struct iscsi_session *iscsi, int first ) {
struct iscsi_bhs_login_request *request = &iscsi->tx_bhs.login_request;
int len;
/* Construct BHS and initiate transmission */
iscsi_start_tx ( iscsi );
request->opcode = ( ISCSI_OPCODE_LOGIN_REQUEST |
ISCSI_FLAG_IMMEDIATE );
request->flags = ( ISCSI_LOGIN_FLAG_TRANSITION |
ISCSI_LOGIN_CSG_OPERATIONAL_NEGOTIATION |
ISCSI_LOGIN_NSG_FULL_FEATURE_PHASE );
/* version_max and version_min left as zero */
if ( first ) {
len = iscsi_build_login_request_strings ( iscsi, NULL, 0 );
ISCSI_SET_LENGTHS ( request->lengths, 0, len );
}
request->isid_iana_en = htonl ( ISCSI_ISID_IANA |
IANA_EN_FEN_SYSTEMS );
/* isid_iana_qual left as zero */
request->tsih = htons ( iscsi->tsih );
/* itt left as zero */
/* cid left as zero */
}
/**
* Transmit data segment of an iSCSI login request PDU
*
* @v iscsi iSCSI session
*
* For login requests, the data segment consists of the login strings.
*/
static void iscsi_tx_login_request ( struct iscsi_session *iscsi ) {
int len;
len = iscsi_build_login_request_strings ( iscsi, tcp_buffer,
tcp_buflen );
tcp_send ( &iscsi->tcp, tcp_buffer + iscsi->tx_offset,
len - iscsi->tx_offset );
}
/**
* Receive data segment of an iSCSI login response PDU
*
* @v iscsi iSCSI session
* @v data Received data
* @v len Length of received data
* @v remaining Data remaining after this data
*
*/
static void iscsi_rx_login_response ( struct iscsi_session *iscsi,
void *data __unused,
size_t len __unused,
size_t remaining __unused ) {
struct iscsi_bhs_login_response *response
= &iscsi->rx_bhs.login_response;
/* Check for fatal errors */
if ( response->status_class != 0 ) {
printf ( "iSCSI login failure: class %02x detail %02x\n",
response->status_class, response->status_detail );
iscsi->status |= ( ISCSI_STATUS_DONE | ISCSI_STATUS_ERR );
tcp_close ( &iscsi->tcp );
return;
}
/* If server did not transition, send back another login
* request without any login strings.
*/
if ( ! ( response->flags & ISCSI_LOGIN_FLAG_TRANSITION ) ) {
iscsi_start_login ( iscsi, 0 );
return;
}
/* Record TSIH for future reference */
iscsi->tsih = ntohl ( response->tsih );
/* Send the SCSI command */
iscsi_start_command ( iscsi );
}
/****************************************************************************
*
* iSCSI to TCP interface
*
*/
static inline struct iscsi_session *
tcp_to_iscsi ( struct tcp_connection *conn ) {
return container_of ( conn, struct iscsi_session, tcp );
}
/**
* Start up a new TX PDU
*
* @v iscsi iSCSI session
*
* This initiates the process of sending a new PDU. Only one PDU may
* be in transit at any one time.
*/
static void iscsi_start_tx ( struct iscsi_session *iscsi ) {
assert ( iscsi->tx_state == ISCSI_TX_IDLE );
/* Initialise TX BHS */
memset ( &iscsi->tx_bhs, 0, sizeof ( iscsi->tx_bhs ) );
iscsi->tx_bhs.common_request.cmdsn = htonl ( iscsi->cmdsn );
iscsi->tx_bhs.common_request.expstatsn = htonl ( iscsi->statsn + 1 );
/* Flag TX engine to start transmitting */
iscsi->tx_state = ISCSI_TX_BHS;
iscsi->tx_offset = 0;
}
/**
* Transmit data segment of an iSCSI PDU
*
* @v iscsi iSCSI session
*
* Handle transmission of part of a PDU data segment. iscsi::tx_bhs
* will be valid when this is called.
*/
static void iscsi_tx_data ( struct iscsi_session *iscsi ) {
struct iscsi_bhs_common *common = &iscsi->tx_bhs.common;
switch ( common->opcode & ISCSI_OPCODE_MASK ) {
case ISCSI_OPCODE_SCSI_COMMAND:
iscsi_tx_command ( iscsi );
break;
case ISCSI_OPCODE_LOGIN_REQUEST:
iscsi_tx_login_request ( iscsi );
break;
default:
assert ( 0 );
break;
}
}
/**
* Handle TCP ACKs
*
* @v iscsi iSCSI session
*
* Updates iscsi->tx_offset and, if applicable, transitions to the
* next TX state.
*/
static void iscsi_acked ( struct tcp_connection *conn, size_t len ) {
struct iscsi_session *iscsi = tcp_to_iscsi ( conn );
struct iscsi_bhs_common *common = &iscsi->tx_bhs.common;
size_t max_tx_offset;
enum iscsi_tx_state next_state;
iscsi->tx_offset += len;
while ( 1 ) {
switch ( iscsi->tx_state ) {
case ISCSI_TX_BHS:
max_tx_offset = sizeof ( iscsi->tx_bhs );
next_state = ISCSI_TX_AHS;
break;
case ISCSI_TX_AHS:
max_tx_offset = 4 * ISCSI_AHS_LEN ( common->lengths );
next_state = ISCSI_TX_DATA;
break;
case ISCSI_TX_DATA:
max_tx_offset = ISCSI_DATA_LEN ( common->lengths );
next_state = ISCSI_TX_DATA_PADDING;
break;
case ISCSI_TX_DATA_PADDING:
max_tx_offset = ISCSI_DATA_PAD_LEN ( common->lengths );
next_state = ISCSI_TX_IDLE;
break;
case ISCSI_TX_IDLE:
return;
default:
assert ( 0 );
return;
}
assert ( iscsi->tx_offset <= max_tx_offset );
/* If the whole of the current portion has not yet
* been acked, stay in this state for now.
*/
if ( iscsi->tx_offset != max_tx_offset )
return;
iscsi->tx_state = next_state;
iscsi->tx_offset = 0;
}
}
/**
* Transmit iSCSI PDU
*
* @v iscsi iSCSI session
*
* Constructs data to be sent for the current TX state
*/
static void iscsi_senddata ( struct tcp_connection *conn ) {
struct iscsi_session *iscsi = tcp_to_iscsi ( conn );
struct iscsi_bhs_common *common = &iscsi->tx_bhs.common;
static const char pad[] = { '\0', '\0', '\0' };
switch ( iscsi->tx_state ) {
case ISCSI_TX_IDLE:
/* Nothing to send */
break;
case ISCSI_TX_BHS:
tcp_send ( conn, &iscsi->tx_bhs.bytes[iscsi->tx_offset],
( sizeof ( iscsi->tx_bhs ) - iscsi->tx_offset ) );
break;
case ISCSI_TX_AHS:
/* We don't yet have an AHS transmission mechanism */
assert ( 0 );
break;
case ISCSI_TX_DATA:
iscsi_tx_data ( iscsi );
break;
case ISCSI_TX_DATA_PADDING:
tcp_send ( conn, pad, ( ISCSI_DATA_PAD_LEN ( common->lengths )
- iscsi->tx_offset ) );
break;
default:
assert ( 0 );
break;
}
}
/**
* Receive data segment of an iSCSI PDU
*
* @v iscsi iSCSI session
* @v data Received data
* @v len Length of received data
* @v remaining Data remaining after this data
*
* Handle processing of part of a PDU data segment. iscsi::rx_bhs
* will be valid when this is called.
*/
static void iscsi_rx_data ( struct iscsi_session *iscsi, void *data,
size_t len, size_t remaining ) {
struct iscsi_bhs_common_response *response
= &iscsi->rx_bhs.common_response;
/* Update cmdsn and statsn */
iscsi->cmdsn = ntohl ( response->expcmdsn );
iscsi->statsn = ntohl ( response->statsn );
/* Increment itt when we receive a final response */
if ( response->flags & ISCSI_FLAG_FINAL )
iscsi->itt++;
switch ( response->opcode & ISCSI_OPCODE_MASK ) {
case ISCSI_OPCODE_LOGIN_RESPONSE:
iscsi_rx_login_response ( iscsi, data, len, remaining );
break;
case ISCSI_OPCODE_DATA_IN:
iscsi_rx_data_in ( iscsi, data, len, remaining );
break;
default:
printf ( "Unknown iSCSI opcode %02x\n", response->opcode );
iscsi->status |= ( ISCSI_STATUS_DONE | ISCSI_STATUS_ERR );
break;
}
}
/**
* Discard portion of an iSCSI PDU.
*
* @v iscsi iSCSI session
* @v data Received data
* @v len Length of received data
* @v remaining Data remaining after this data
*
* This discards data from a portion of a received PDU.
*/
static void iscsi_rx_discard ( struct iscsi_session *iscsi __unused,
void *data __unused, size_t len __unused,
size_t remaining __unused ) {
/* Do nothing */
}
/**
* Receive basic header segment of an iSCSI PDU
*
* @v iscsi iSCSI session
* @v data Received data
* @v len Length of received data
* @v remaining Data remaining after this data
*
* This fills in iscsi::rx_bhs with the data from the BHS portion of
* the received PDU.
*/
static void iscsi_rx_bhs ( struct iscsi_session *iscsi, void *data,
size_t len, size_t remaining __unused ) {
memcpy ( &iscsi->rx_bhs.bytes[iscsi->rx_offset], data, len );
}
/**
* Receive new data
*
* @v tcp TCP connection
* @v data Received data
* @v len Length of received data
*
* This handles received PDUs. The receive strategy is to fill in
* iscsi::rx_bhs with the contents of the BHS portion of the PDU,
* throw away any AHS portion, and then process each part of the data
* portion as it arrives. The data processing routine therefore
* always has a full copy of the BHS available, even for portions of
* the data in different packets to the BHS.
*/
static void iscsi_newdata ( struct tcp_connection *conn, void *data,
size_t len ) {
struct iscsi_session *iscsi = tcp_to_iscsi ( conn );
struct iscsi_bhs_common *common = &iscsi->rx_bhs.common;
void ( *process ) ( struct iscsi_session *iscsi, void *data,
size_t len, size_t remaining );
size_t max_rx_offset;
enum iscsi_rx_state next_state;
size_t frag_len;
size_t remaining;
while ( 1 ) {
switch ( iscsi->rx_state ) {
case ISCSI_RX_BHS:
process = iscsi_rx_bhs;
max_rx_offset = sizeof ( iscsi->rx_bhs );
next_state = ISCSI_RX_AHS;
break;
case ISCSI_RX_AHS:
process = iscsi_rx_discard;
max_rx_offset = 4 * ISCSI_AHS_LEN ( common->lengths );
next_state = ISCSI_RX_DATA;
break;
case ISCSI_RX_DATA:
process = iscsi_rx_data;
max_rx_offset = ISCSI_DATA_LEN ( common->lengths );
next_state = ISCSI_RX_DATA_PADDING;
break;
case ISCSI_RX_DATA_PADDING:
process = iscsi_rx_discard;
max_rx_offset = ISCSI_DATA_PAD_LEN ( common->lengths );
next_state = ISCSI_RX_BHS;
break;
default:
assert ( 0 );
return;
}
frag_len = max_rx_offset - iscsi->rx_offset;
if ( frag_len > len )
frag_len = len;
remaining = max_rx_offset - iscsi->rx_offset - frag_len;
process ( iscsi, data, frag_len, remaining );
iscsi->rx_offset += frag_len;
data += frag_len;
len -= frag_len;
/* If all the data for this state has not yet been
* received, stay in this state for now.
*/
if ( iscsi->rx_offset != max_rx_offset )
return;
iscsi->rx_state = next_state;
iscsi->rx_offset = 0;
}
}
/**
* Handle TCP connection closure
*
* @v conn TCP connection
* @v status Error code, if any
*
*/
static void iscsi_closed ( struct tcp_connection *conn, int status __unused ) {
struct iscsi_session *iscsi = tcp_to_iscsi ( conn );
/* Clear connected flag */
iscsi->status &= ~ISCSI_STATUS_CONNECTED;
/* Retry connection if within the retry limit, otherwise fail */
if ( ++iscsi->retry_count <= ISCSI_MAX_RETRIES ) {
tcp_connect ( conn );
} else {
iscsi->status |= ( ISCSI_STATUS_DONE | ISCSI_STATUS_ERR );
}
}
/**
* Handle TCP connection opening
*
* @v conn TCP connection
*
*/
static void iscsi_connected ( struct tcp_connection *conn ) {
struct iscsi_session *iscsi = tcp_to_iscsi ( conn );
/* Set connected flag and reset retry count */
iscsi->status |= ISCSI_STATUS_CONNECTED;
iscsi->retry_count = 0;
/* Prepare to receive PDUs. */
iscsi->rx_state = ISCSI_RX_BHS;
iscsi->rx_offset = 0;
/* Start logging in */
iscsi_start_login ( iscsi, 1 );
}
/** iSCSI TCP operations */
static struct tcp_operations iscsi_tcp_operations = {
.closed = iscsi_closed,
.connected = iscsi_connected,
.acked = iscsi_acked,
.newdata = iscsi_newdata,
.senddata = iscsi_senddata,
};
/**
* Issue SCSI command via iSCSI session
*
* @v iscsi iSCSI session
* @v command SCSI command
* @ret rc Return status code
*/
static int iscsi_command ( struct iscsi_session *iscsi,
struct scsi_command *command ) {
iscsi->command = command;
iscsi->status &= ~( ISCSI_STATUS_DONE | ISCSI_STATUS_ERR );
if ( iscsi->status & ISCSI_STATUS_CONNECTED ) {
iscsi_start_command ( iscsi );
} else {
iscsi->tcp.tcp_op = &iscsi_tcp_operations;
tcp_connect ( &iscsi->tcp );
}
while ( ! ( iscsi->status & ISCSI_STATUS_DONE ) ) {
step();
}
iscsi->command = NULL;
return ( ( iscsi->status & ISCSI_STATUS_ERR ) ? -EIO : 0 );
}
/**
* Issue SCSI command via iSCSI device
*
* @v scsi SCSI device
* @v command SCSI command
* @ret rc Return status code
*/
static int iscsi_scsi_command ( struct scsi_device *scsi,
struct scsi_command *command ) {
struct iscsi_device *iscsidev
= container_of ( scsi, struct iscsi_device, scsi );
return iscsi_command ( &iscsidev->iscsi, command );
}
/**
* Initialise iSCSI device
*
* @v iscsidev iSCSI device
*/
int init_iscsidev ( struct iscsi_device *iscsidev ) {
iscsidev->scsi.command = iscsi_scsi_command;
iscsidev->scsi.lun = iscsidev->iscsi.lun;
return init_scsidev ( &iscsidev->scsi );
}
