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iSCSI writes seem to be working (at least, the ethereal trace shows no

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errors; still need to verify data integrity).

SCSI response PDUs are handled: status and sense data (if available) are
returned via the scsi_command structure.

Updated iSCSI session parameter usage.
This commit is contained in:
Michael Brown 2006-05-19 00:20:08 +00:00
parent b531bd2bda
commit a280587cde
3 changed files with 304 additions and 54 deletions
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138
src/include/gpxe/iscsi.h
View File

@ -81,33 +81,6 @@ struct iscsi_bhs_common {
/** Final PDU of a sequence */
#define ISCSI_FLAG_FINAL 0x80
/**
* iSCSI basic header segment common request fields
*
*/
struct iscsi_bhs_common_request {
/** 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[4];
/** Command sequence number */
uint32_t cmdsn;
/** Expected status sequence number */
uint32_t expstatsn;
/** Fields specific to the PDU type */
uint8_t other_d[16];
};
/**
* iSCSI basic header segment common request fields
*
@ -328,8 +301,16 @@ struct iscsi_bhs_scsi_response {
/** SCSI target failure */
#define ISCSI_RESPONSE_TARGET_FAILURE 0x01
/** SCSI sense response code offset
*
* The SCSI response may contain unsolicited sense data in the data
* segment. If it does, this is the offset to the sense response code
* byte, which is the only byte we care about.
*/
#define ISCSI_SENSE_RESPONSE_CODE_OFFSET 2
/**
* iSCSI data in basic header segment
* iSCSI data-in basic header segment
*
*/
struct iscsi_bhs_data_in {
@ -363,7 +344,7 @@ struct iscsi_bhs_data_in {
uint32_t residual_count;
};
/** Data in opcode */
/** Data-in opcode */
#define ISCSI_OPCODE_DATA_IN 0x25
/** Data requires acknowledgement */
@ -375,21 +356,94 @@ struct iscsi_bhs_data_in {
/** Data underflow occurred */
#define ISCSI_DATA_FLAG_UNDERFLOW 0x02
/** SCSI status code and verflow/underflow flags are valid */
/** SCSI status code and overflow/underflow flags are valid */
#define ISCSI_DATA_FLAG_STATUS 0x01
/**
* iSCSI data-out basic header segment
*
*/
struct iscsi_bhs_data_out {
/** Opcode */
uint8_t opcode;
/** Flags */
uint8_t flags;
/** Reserved */
uint16_t reserved_a;
/** Segment lengths */
union iscsi_segment_lengths lengths;
/** Logical Unit Number */
uint64_t lun;
/** Initiator Task Tag */
uint32_t itt;
/** Target Transfer Tag */
uint32_t ttt;
/** Reserved */
uint32_t reserved_b;
/** Expected status sequence number */
uint32_t expstatsn;
/** Reserved */
uint32_t reserved_c;
/** Data sequence number */
uint32_t datasn;
/** Buffer offset */
uint32_t offset;
/** Reserved */
uint32_t reserved_d;
};
/** Data-out opcode */
#define ISCSI_OPCODE_DATA_OUT 0x05
/**
* iSCSI request to transfer basic header segment
*
*/
struct iscsi_bhs_r2t {
/** Opcode */
uint8_t opcode;
/** Flags */
uint8_t flags;
/** Reserved */
uint16_t reserved_a;
/** Segment lengths */
union iscsi_segment_lengths lengths;
/** Logical Unit Number */
uint64_t lun;
/** 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;
/** R2T sequence number */
uint32_t r2tsn;
/** Buffer offset */
uint32_t offset;
/** Desired data transfer length */
uint32_t len;
};
/** R2T opcode */
#define ISCSI_OPCODE_R2T 0x31
/**
* An iSCSI basic header segment
*/
union iscsi_bhs {
struct iscsi_bhs_common common;
struct iscsi_bhs_common_request common_request;
struct iscsi_bhs_common_response common_response;
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;
struct iscsi_bhs_data_out data_out;
struct iscsi_bhs_r2t r2t;
unsigned char bytes[ sizeof ( struct iscsi_bhs_common ) ];
};
@ -452,9 +506,29 @@ struct iscsi_session {
/** Initiator task tag
*
* This is the tag of the current command. It is incremented
* whenever a final response PDU is received.
* whenever a new command is started.
*/
uint32_t itt;
/** Target transfer tag
*
* This is the tag attached to a sequence of data-out PDUs in
* response to an R2T.
*/
uint32_t ttt;
/**
* Transfer offset
*
* This is the offset for an in-progress sequence of data-out
* PDUs in response to an R2T.
*/
uint32_t transfer_offset;
/**
* Transfer length
*
* This is the length for an in-progress sequence of data-out
* PDUs in response to an R2T.
*/
uint32_t transfer_len;
/** Command sequence number
*
* This is the sequence number of the current command, used to

10
src/include/gpxe/scsi.h
View File

@ -136,6 +136,10 @@ struct scsi_command {
* Must be zero if @c data_in is NULL
*/
size_t data_in_len;
/** SCSI statua code */
uint8_t status;
/** SCSI sense response code */
uint8_t sense_response;
};
/** A SCSI device */
@ -154,6 +158,12 @@ struct scsi_device {
* @v scsi SCSI device
* @v command SCSI command
* @ret rc Return status code
*
* Note that a successful return status code indicates only
* that the SCSI command completed. The caller must check the
* status field in the command structure to see if, for
* example, the device returned CHECK CONDITION or some other
* non-success status code.
*/
int ( * command ) ( struct scsi_device *scsi,
struct scsi_command *command );

210
src/net/tcp/iscsi.c
View File

@ -33,6 +33,8 @@
*/
static void iscsi_start_tx ( struct iscsi_session *iscsi );
static void iscsi_start_data_out ( struct iscsi_session *iscsi,
unsigned int datasn );
/****************************************************************************
*
@ -44,6 +46,11 @@ static void iscsi_start_tx ( struct iscsi_session *iscsi );
* Build iSCSI SCSI command BHS
*
* @v iscsi iSCSI session
*
* We don't currently support bidirectional commands (i.e. with both
* Data-In and Data-Out segments); these would require providing code
* to generate an AHS, and there doesn't seem to be any need for it at
* the moment.
*/
static void iscsi_start_command ( struct iscsi_session *iscsi ) {
struct iscsi_bhs_scsi_command *command = &iscsi->tx_bhs.scsi_command;
@ -59,21 +66,49 @@ static void iscsi_start_command ( struct iscsi_session *iscsi ) {
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);
/* lengths left as zero */
command->lun = iscsi->lun;
command->itt = htonl ( iscsi->itt );
command->exp_len = htonl ( iscsi->command->data_in_len );
command->itt = htonl ( ++iscsi->itt );
command->exp_len = htonl ( iscsi->command->data_in_len |
iscsi->command->data_out_len );
command->cmdsn = htonl ( iscsi->cmdsn );
command->expstatsn = htonl ( iscsi->statsn + 1 );
memcpy ( &command->cdb, &iscsi->command->cdb, sizeof ( command->cdb ));
}
/**
* Send iSCSI SCSI command data
* Receive data segment of an iSCSI SCSI 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_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 );
static void iscsi_rx_scsi_response ( struct iscsi_session *iscsi, void *data,
size_t len, size_t remaining ) {
struct iscsi_bhs_scsi_response *response
= &iscsi->rx_bhs.scsi_response;
int sense_offset;
/* Capture the sense response code as it floats past, if present */
sense_offset = ISCSI_SENSE_RESPONSE_CODE_OFFSET - iscsi->rx_offset;
if ( ( sense_offset >= 0 ) && len ) {
iscsi->command->sense_response =
* ( ( char * ) data + sense_offset );
}
/* Wait for whole SCSI response to arrive */
if ( remaining )
return;
/* Record SCSI status code */
iscsi->command->status = response->status;
/* Mark as completed, with error if applicable */
iscsi->status |= ISCSI_STATUS_DONE;
if ( response->response != ISCSI_RESPONSE_COMMAND_COMPLETE )
iscsi->status |= ISCSI_STATUS_ERR;
}
/**
@ -86,7 +121,7 @@ static void iscsi_tx_command ( struct iscsi_session *iscsi ) {
*
*/
static void iscsi_rx_data_in ( struct iscsi_session *iscsi, void *data,
size_t len, size_t remaining ) {
size_t len, size_t remaining __unused ) {
struct iscsi_bhs_data_in *data_in = &iscsi->rx_bhs.data_in;
unsigned long offset;
@ -97,9 +132,109 @@ static void iscsi_rx_data_in ( struct iscsi_session *iscsi, void *data,
assert ( ( offset + len ) <= iscsi->command->data_in_len );
memcpy ( ( iscsi->command->data_in + offset ), data, len );
/* Record SCSI status, if present */
if ( data_in->flags & ISCSI_DATA_FLAG_STATUS )
iscsi->command->status = data_in->status;
/* If this is the end, flag as complete */
if ( ( data_in->flags & ISCSI_FLAG_FINAL ) && ( remaining == 0 ) )
if ( ( offset + len ) == iscsi->command->data_in_len ) {
assert ( data_in->flags & ISCSI_FLAG_FINAL );
assert ( remaining == 0 );
iscsi->status |= ISCSI_STATUS_DONE;
}
}
/**
* Receive data segment of an iSCSI R2T 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_r2t ( struct iscsi_session *iscsi, void *data __unused,
size_t len __unused, size_t remaining __unused ) {
struct iscsi_bhs_r2t *r2t = &iscsi->rx_bhs.r2t;
/* Record transfer parameters and trigger first data-out */
iscsi->ttt = ntohl ( r2t->ttt );
iscsi->transfer_offset = ntohl ( r2t->offset );
iscsi->transfer_len = ntohl ( r2t->len );
iscsi_start_data_out ( iscsi, 0 );
}
/**
* Build iSCSI data-out BHS
*
* @v iscsi iSCSI session
* @v datasn Data sequence number within the transfer
*
*/
static void iscsi_start_data_out ( struct iscsi_session *iscsi,
unsigned int datasn ) {
struct iscsi_bhs_data_out *data_out = &iscsi->tx_bhs.data_out;
unsigned long offset;
unsigned long remaining;
unsigned long len;
/* We always send 512-byte Data-Out PDUs; this removes the
* need to worry about the target's MaxRecvDataSegmentLength.
*/
offset = datasn * 512;
remaining = iscsi->transfer_len - offset;
len = remaining;
if ( len > 512 )
len = 512;
/* Construct BHS and initiate transmission */
iscsi_start_tx ( iscsi );
data_out->opcode = ISCSI_OPCODE_DATA_OUT;
if ( len == remaining )
data_out->flags = ( ISCSI_FLAG_FINAL );
ISCSI_SET_LENGTHS ( data_out->lengths, 0, len );
data_out->lun = iscsi->lun;
data_out->itt = htonl ( iscsi->itt );
data_out->ttt = htonl ( iscsi->ttt );
data_out->expstatsn = htonl ( iscsi->statsn + 1 );
data_out->datasn = htonl ( datasn );
data_out->offset = htonl ( iscsi->transfer_offset + offset );
}
/**
* Complete iSCSI data-out PDU transmission
*
* @v iscsi iSCSI session
*
*/
static void iscsi_data_out_done ( struct iscsi_session *iscsi ) {
struct iscsi_bhs_data_out *data_out = &iscsi->tx_bhs.data_out;
/* If we haven't reached the end of the sequence, start
* sending the next data-out PDU.
*/
if ( ! ( data_out->flags & ISCSI_FLAG_FINAL ) )
iscsi_start_data_out ( iscsi, ntohl ( data_out->datasn ) + 1 );
}
/**
* Send iSCSI data-out data segment
*
* @v iscsi iSCSI session
*/
static void iscsi_tx_data_out ( struct iscsi_session *iscsi ) {
struct iscsi_bhs_data_out *data_out = &iscsi->tx_bhs.data_out;
unsigned long offset;
unsigned long len;
offset = ( iscsi->transfer_offset + ntohl ( data_out->offset ) +
iscsi->tx_offset );
len = ( ISCSI_DATA_LEN ( data_out->lengths ) - iscsi->tx_offset );
assert ( iscsi->command != NULL );
assert ( iscsi->command->data_out != NULL );
assert ( ( offset + len ) <= iscsi->command->data_out_len );
tcp_send ( &iscsi->tcp, iscsi->command->data_out + offset, len );
}
/****************************************************************************
@ -121,11 +256,11 @@ static int iscsi_build_login_request_strings ( struct iscsi_session *iscsi,
return snprintf ( data, len,
"InitiatorName=%s%c"
"TargetName=%s%c"
"MaxRecvDataSegmentLength=512%c"
"SessionType=Normal%c"
"DataDigest=None%c"
"HeaderDigest=None%c"
"ErrorRecoveryLevel=0%c",
"DefaultTime2Wait=0%c"
"DefaultTime2Retain=0%c",
iscsi->initiator, 0, iscsi->target, 0,
0, 0, 0, 0, 0 );
}
@ -134,7 +269,7 @@ static int iscsi_build_login_request_strings ( struct iscsi_session *iscsi,
* Build iSCSI login request BHS
*
* @v iscsi iSCSI session
* @v first Login request is the first request of a session
* @v first Login request is the first in a sequence
*/
static void iscsi_start_login ( struct iscsi_session *iscsi, int first ) {
struct iscsi_bhs_login_request *request = &iscsi->tx_bhs.login_request;
@ -156,8 +291,12 @@ static void iscsi_start_login ( struct iscsi_session *iscsi, int first ) {
IANA_EN_FEN_SYSTEMS );
/* isid_iana_qual left as zero */
request->tsih = htons ( iscsi->tsih );
/* itt left as zero */
if ( first )
iscsi->itt++;
request->itt = htonl ( iscsi->itt );
/* cid left as zero */
request->cmdsn = htonl ( iscsi->cmdsn );
request->expstatsn = htonl ( iscsi->statsn + 1 );
}
/**
@ -240,8 +379,6 @@ static void iscsi_start_tx ( struct iscsi_session *iscsi ) {
/* 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;
@ -260,8 +397,8 @@ 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 );
case ISCSI_OPCODE_DATA_OUT:
iscsi_tx_data_out ( iscsi );
break;
case ISCSI_OPCODE_LOGIN_REQUEST:
iscsi_tx_login_request ( iscsi );
@ -272,6 +409,27 @@ static void iscsi_tx_data ( struct iscsi_session *iscsi ) {
}
}
/**
* Complete iSCSI PDU transmission
*
* @v iscsi iSCSI session
*
* Called when a PDU has been completely transmitted and the TX state
* machine is about to enter the idle state. iscsi::tx_bhs will be
* valid for the just-completed PDU when this is called.
*/
static void iscsi_tx_done ( struct iscsi_session *iscsi ) {
struct iscsi_bhs_common *common = &iscsi->tx_bhs.common;
switch ( common->opcode & ISCSI_OPCODE_MASK ) {
case ISCSI_OPCODE_DATA_OUT:
iscsi_data_out_done ( iscsi );
default:
/* No action */
break;
}
}
/**
* Handle TCP ACKs
*
@ -318,9 +476,14 @@ static void iscsi_acked ( struct tcp_connection *conn, size_t len ) {
*/
if ( iscsi->tx_offset != max_tx_offset )
return;
/* Move to next state. Call iscsi_tx_done() when PDU
* transmission is complete.
*/
iscsi->tx_state = next_state;
iscsi->tx_offset = 0;
if ( next_state == ISCSI_TX_IDLE )
iscsi_tx_done ( iscsi );
}
}
@ -381,17 +544,19 @@ static void iscsi_rx_data ( struct iscsi_session *iscsi, void *data,
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_SCSI_RESPONSE:
iscsi_rx_scsi_response ( iscsi, data, len, remaining );
break;
case ISCSI_OPCODE_DATA_IN:
iscsi_rx_data_in ( iscsi, data, len, remaining );
break;
case ISCSI_OPCODE_R2T:
iscsi_rx_r2t ( iscsi, data, len, remaining );
break;
default:
printf ( "Unknown iSCSI opcode %02x\n", response->opcode );
iscsi->status |= ( ISCSI_STATUS_DONE | ISCSI_STATUS_ERR );
@ -521,6 +686,7 @@ static void iscsi_closed ( struct tcp_connection *conn, int status __unused ) {
if ( ++iscsi->retry_count <= ISCSI_MAX_RETRIES ) {
tcp_connect ( conn );
} else {
printf ( "iSCSI retry count exceeded\n" );
iscsi->status |= ( ISCSI_STATUS_DONE | ISCSI_STATUS_ERR );
}
}