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xNBA/src/net/tcp/iscsi.c
Michael Brown 9b28b25332 iSCSI updated to use data-xfer interface on the socket side (TCP). 
SCSI interface not yet implemented.
2007-07-08 16:04:13 +01:00

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/*
* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stddef.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <assert.h>
#include <byteswap.h>
#include <gpxe/vsprintf.h>
#include <gpxe/socket.h>
#include <gpxe/xfer.h>
#include <gpxe/open.h>
#include <gpxe/scsi.h>
#include <gpxe/process.h>
#include <gpxe/uaccess.h>
#include <gpxe/tcpip.h>
#include <gpxe/iscsi.h>
/** @file
*
* iSCSI protocol
*
*/
static void iscsi_start_tx ( struct iscsi_session *iscsi );
static void iscsi_start_login ( struct iscsi_session *iscsi );
static void iscsi_start_data_out ( struct iscsi_session *iscsi,
unsigned int datasn );
/**
* Finish receiving PDU data into buffer
*
* @v iscsi iSCSI session
*/
static void iscsi_rx_buffered_data_done ( struct iscsi_session *iscsi ) {
free ( iscsi->rx_buffer );
iscsi->rx_buffer = NULL;
}
/**
* Free iSCSI session
*
* @v refcnt Reference counter
*/
static void iscsi_free ( struct refcnt *refcnt ) {
struct iscsi_session *iscsi =
container_of ( refcnt, struct iscsi_session, refcnt );
free ( iscsi->initiator_iqn );
free ( iscsi->target_address );
free ( iscsi->target_iqn );
free ( iscsi->username );
free ( iscsi->password );
chap_finish ( &iscsi->chap );
iscsi_rx_buffered_data_done ( iscsi );
free ( iscsi );
}
/**
* Open iSCSI transport-layer connection
*
* @v iscsi iSCSI session
* @ret rc Return status code
*/
static int iscsi_open_connection ( struct iscsi_session *iscsi ) {
struct sockaddr_tcpip target;
int rc;
assert ( iscsi->tx_state == ISCSI_TX_IDLE );
assert ( iscsi->rx_state == ISCSI_RX_BHS );
assert ( iscsi->rx_offset == 0 );
/* Open socket */
memset ( &target, 0, sizeof ( target ) );
target.st_port = htons ( ISCSI_PORT );
if ( ( rc = xfer_open_named_socket ( &iscsi->socket, SOCK_STREAM,
( struct sockaddr * ) &target,
iscsi->target_address,
NULL ) ) != 0 ) {
DBGC ( iscsi, "iSCSI %p could not open socket: %s\n",
iscsi, strerror ( rc ) );
return rc;
}
/* Enter security negotiation phase */
iscsi->status = ( ISCSI_STATUS_SECURITY_NEGOTIATION_PHASE |
ISCSI_STATUS_STRINGS_SECURITY );
/* Assign fresh initiator task tag */
iscsi->itt++;
/* Initiate login */
iscsi_start_login ( iscsi );
return 0;
}
/**
* Close iSCSI transport-layer connection
*
* @v iscsi iSCSI session
* @v rc Reason for close
*
* Closes the transport-layer connection and resets the session state
* ready to attempt a fresh login.
*/
static void iscsi_close_connection ( struct iscsi_session *iscsi, int rc ) {
/* Close all data transfer interfaces */
xfer_close ( &iscsi->socket, rc );
/* Clear connection status */
iscsi->status = 0;
/* Reset TX and RX state machines */
iscsi->tx_state = ISCSI_TX_IDLE;
iscsi->rx_state = ISCSI_RX_BHS;
/* Free any temporary dynamically allocated memory */
chap_finish ( &iscsi->chap );
iscsi_rx_buffered_data_done ( iscsi );
}
/**
* Mark iSCSI SCSI operation as complete
*
* @v iscsi iSCSI session
* @v rc Return status code
*
* Note that iscsi_scsi_done() will not close the connection, and must
* therefore be called only when the internal state machines are in an
* appropriate state, otherwise bad things may happen on the next call
* to iscsi_issue(). The general rule is to call iscsi_scsi_done()
* only at the end of receiving a PDU; at this point the TX and RX
* engines should both be idle.
*/
static void iscsi_scsi_done ( struct iscsi_session *iscsi, int rc ) {
assert ( iscsi->tx_state == ISCSI_TX_IDLE );
/* Clear current SCSI command */
iscsi->command = NULL;
/* Mark asynchronous operation as complete */
async_done ( &iscsi->async, rc );
}
/****************************************************************************
*
* iSCSI SCSI command issuing
*
*/
/**
* 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;
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;
/* lengths left as zero */
command->lun = iscsi->lun;
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 ));
DBGC ( iscsi, "iSCSI %p start " SCSI_CDB_FORMAT " %s %#x\n",
iscsi, SCSI_CDB_DATA ( command->cdb ),
( iscsi->command->data_in ? "in" : "out" ),
( iscsi->command->data_in ?
iscsi->command->data_in_len : iscsi->command->data_out_len ));
}
/**
* 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
* @ret rc Return status code
*/
static int iscsi_rx_scsi_response ( struct iscsi_session *iscsi,
const 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 0;
/* Record SCSI status code */
iscsi->command->status = response->status;
/* Check for errors */
if ( response->response != ISCSI_RESPONSE_COMMAND_COMPLETE )
return -EIO;
/* Mark as completed */
iscsi_scsi_done ( iscsi, 0 );
return 0;
}
/**
* 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
* @ret rc Return status code
*/
static int iscsi_rx_data_in ( struct iscsi_session *iscsi,
const void *data, size_t len,
size_t remaining __unused ) {
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 );
assert ( ( offset + len ) <= iscsi->command->data_in_len );
copy_to_user ( 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 ( ( offset + len ) == iscsi->command->data_in_len ) {
assert ( data_in->flags & ISCSI_FLAG_FINAL );
assert ( remaining == 0 );
iscsi_scsi_done ( iscsi, 0 );
}
return 0;
}
/**
* 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
* @ret rc Return status code
*/
static int iscsi_rx_r2t ( struct iscsi_session *iscsi,
const 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 );
return 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 );
DBGC ( iscsi, "iSCSI %p start data out DataSN %#x len %#lx\n",
iscsi, datasn, len );
}
/**
* 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
* @ret rc Return status code
*/
static int iscsi_tx_data_out ( struct iscsi_session *iscsi ) {
struct iscsi_bhs_data_out *data_out = &iscsi->tx_bhs.data_out;
struct io_buffer *iobuf;
unsigned long offset;
size_t len;
offset = ntohl ( data_out->offset );
len = ISCSI_DATA_LEN ( data_out->lengths );
assert ( iscsi->command != NULL );
assert ( iscsi->command->data_out );
assert ( ( offset + len ) <= iscsi->command->data_out_len );
iobuf = xfer_alloc_iob ( &iscsi->socket, len );
if ( ! iobuf )
return -ENOMEM;
copy_from_user ( iob_put ( iobuf, len ),
iscsi->command->data_out, offset, len );
return xfer_deliver_iob ( &iscsi->socket, iobuf );
}
/****************************************************************************
*
* 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. We want the following settings:
*
* HeaderDigest=None
* DataDigest=None
* MaxConnections is irrelevant; we make only one connection anyway
* InitialR2T=Yes [1]
* ImmediateData is irrelevant; we never send immediate data
* MaxRecvDataSegmentLength=8192 (default; we don't care)
* MaxBurstLength=262144 (default; we don't care)
* FirstBurstLength=262144 (default; we don't care)
* DefaultTime2Wait=0 [2]
* DefaultTime2Retain=0 [2]
* MaxOutstandingR2T=1
* DataPDUInOrder=Yes
* DataSequenceInOrder=Yes
* ErrorRecoveryLevel=0
*
* [1] InitialR2T has an OR resolution function, so the target may
* force us to use it. We therefore simplify our logic by always
* using it.
*
* [2] These ensure that we can safely start a new task once we have
* reconnected after a failure, without having to manually tidy up
* after the old one.
*/
static int iscsi_build_login_request_strings ( struct iscsi_session *iscsi,
void *data, size_t len ) {
unsigned int used = 0;
unsigned int i;
if ( iscsi->status & ISCSI_STATUS_STRINGS_SECURITY ) {
used += ssnprintf ( data + used, len - used,
"InitiatorName=%s%c"
"TargetName=%s%c"
"SessionType=Normal%c"
"AuthMethod=CHAP,None%c",
iscsi->initiator_iqn, 0,
iscsi->target_iqn, 0, 0, 0 );
}
if ( iscsi->status & ISCSI_STATUS_STRINGS_CHAP_ALGORITHM ) {
used += ssnprintf ( data + used, len - used, "CHAP_A=5%c", 0 );
}
if ( ( iscsi->status & ISCSI_STATUS_STRINGS_CHAP_RESPONSE ) &&
iscsi->username ) {
used += ssnprintf ( data + used, len - used,
"CHAP_N=%s%cCHAP_R=0x",
iscsi->username, 0 );
for ( i = 0 ; i < iscsi->chap.response_len ; i++ ) {
used += ssnprintf ( data + used, len - used, "%02x",
iscsi->chap.response[i] );
}
used += ssnprintf ( data + used, len - used, "%c", 0 );
}
if ( iscsi->status & ISCSI_STATUS_STRINGS_OPERATIONAL ) {
used += ssnprintf ( data + used, len - used,
"HeaderDigest=None%c"
"DataDigest=None%c"
"InitialR2T=Yes%c"
"DefaultTime2Wait=0%c"
"DefaultTime2Retain=0%c"
"MaxOutstandingR2T=1%c"
"DataPDUInOrder=Yes%c"
"DataSequenceInOrder=Yes%c"
"ErrorRecoveryLevel=0%c",
0, 0, 0, 0, 0, 0, 0, 0, 0 );
}
return used;
}
/**
* Build iSCSI login request BHS
*
* @v iscsi iSCSI session
*/
static void iscsi_start_login ( struct iscsi_session *iscsi ) {
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->status & ISCSI_STATUS_PHASE_MASK ) |
ISCSI_LOGIN_FLAG_TRANSITION );
/* version_max and version_min left as zero */
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 );
request->itt = htonl ( iscsi->itt );
/* cid left as zero */
request->cmdsn = htonl ( iscsi->cmdsn );
request->expstatsn = htonl ( iscsi->statsn + 1 );
}
/**
* Complete iSCSI login request PDU transmission
*
* @v iscsi iSCSI session
*
*/
static void iscsi_login_request_done ( struct iscsi_session *iscsi ) {
/* Clear any "strings to send" flags */
iscsi->status &= ~ISCSI_STATUS_STRINGS_MASK;
/* Free any dynamically allocated storage used for login */
chap_finish ( &iscsi->chap );
}
/**
* Transmit data segment of an iSCSI login request PDU
*
* @v iscsi iSCSI session
* @ret rc Return status code
*
* For login requests, the data segment consists of the login strings.
*/
static int iscsi_tx_login_request ( struct iscsi_session *iscsi ) {
struct iscsi_bhs_login_request *request = &iscsi->tx_bhs.login_request;
struct io_buffer *iobuf;
size_t len;
len = ISCSI_DATA_LEN ( request->lengths );
iobuf = xfer_alloc_iob ( &iscsi->socket, len );
if ( ! iobuf )
return -ENOMEM;
iob_put ( iobuf, len );
iscsi_build_login_request_strings ( iscsi, iobuf->data, len );
return xfer_deliver_iob ( &iscsi->socket, iobuf );
}
/**
* Handle iSCSI TargetAddress text value
*
* @v iscsi iSCSI session
* @v value TargetAddress value
* @ret rc Return status code
*/
static int iscsi_handle_targetaddress_value ( struct iscsi_session *iscsi,
const char *value ) {
DBGC ( iscsi, "iSCSI %p will redirect to %s\n", iscsi, value );
/* Replace target address */
free ( iscsi->target_address );
iscsi->target_address = strdup ( value );
if ( ! iscsi->target_address )
return -ENOMEM;
return 0;
}
/**
* Handle iSCSI AuthMethod text value
*
* @v iscsi iSCSI session
* @v value AuthMethod value
* @ret rc Return status code
*/
static int iscsi_handle_authmethod_value ( struct iscsi_session *iscsi,
const char *value ) {
/* If server requests CHAP, send the CHAP_A string */
if ( strcmp ( value, "CHAP" ) == 0 ) {
DBGC ( iscsi, "iSCSI %p initiating CHAP authentication\n",
iscsi );
iscsi->status |= ISCSI_STATUS_STRINGS_CHAP_ALGORITHM;
}
return 0;
}
/**
* Handle iSCSI CHAP_A text value
*
* @v iscsi iSCSI session
* @v value CHAP_A value
* @ret rc Return status code
*/
static int iscsi_handle_chap_a_value ( struct iscsi_session *iscsi,
const char *value ) {
int rc;
/* We only ever offer "5" (i.e. MD5) as an algorithm, so if
* the server responds with anything else it is a protocol
* violation.
*/
if ( strcmp ( value, "5" ) != 0 ) {
DBGC ( iscsi, "iSCSI %p got invalid CHAP algorithm \"%s\"\n",
iscsi, value );
return -EPROTO;
}
/* Prepare for CHAP with MD5 */
if ( ( rc = chap_init ( &iscsi->chap, &md5_algorithm ) ) != 0 ) {
DBGC ( iscsi, "iSCSI %p could not initialise CHAP: %s\n",
iscsi, strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Handle iSCSI CHAP_I text value
*
* @v iscsi iSCSI session
* @v value CHAP_I value
* @ret rc Return status code
*/
static int iscsi_handle_chap_i_value ( struct iscsi_session *iscsi,
const char *value ) {
unsigned int identifier;
char *endp;
/* The CHAP identifier is an integer value */
identifier = strtoul ( value, &endp, 0 );
if ( *endp != '\0' ) {
DBGC ( iscsi, "iSCSI %p saw invalid CHAP identifier \"%s\"\n",
iscsi, value );
return -EPROTO;
}
/* Identifier and secret are the first two components of the
* challenge.
*/
chap_set_identifier ( &iscsi->chap, identifier );
if ( iscsi->password ) {
chap_update ( &iscsi->chap, iscsi->password,
strlen ( iscsi->password ) );
}
return 0;
}
/**
* Handle iSCSI CHAP_C text value
*
* @v iscsi iSCSI session
* @v value CHAP_C value
* @ret rc Return status code
*/
static int iscsi_handle_chap_c_value ( struct iscsi_session *iscsi,
const char *value ) {
char buf[3];
char *endp;
uint8_t byte;
/* Check and strip leading "0x" */
if ( ( value[0] != '0' ) || ( value[1] != 'x' ) ) {
DBGC ( iscsi, "iSCSI %p saw invalid CHAP challenge \"%s\"\n",
iscsi, value );
}
value += 2;
/* Process challenge an octet at a time */
for ( ; ( value[0] && value[1] ) ; value += 2 ) {
memcpy ( buf, value, 2 );
buf[3] = 0;
byte = strtoul ( buf, &endp, 16 );
if ( *endp != '\0' ) {
DBGC ( iscsi, "iSCSI %p saw invalid CHAP challenge "
"byte \"%s\"\n", iscsi, buf );
return -EPROTO;
}
chap_update ( &iscsi->chap, &byte, sizeof ( byte ) );
}
/* Build CHAP response */
DBGC ( iscsi, "iSCSI %p sending CHAP response\n", iscsi );
chap_respond ( &iscsi->chap );
iscsi->status |= ISCSI_STATUS_STRINGS_CHAP_RESPONSE;
return 0;
}
/** An iSCSI text string that we want to handle */
struct iscsi_string_type {
/** String key
*
* This is the portion up to and including the "=" sign,
* e.g. "InitiatorName=", "CHAP_A=", etc.
*/
const char *key;
/** Handle iSCSI string value
*
* @v iscsi iSCSI session
* @v value iSCSI string value
* @ret rc Return status code
*/
int ( * handle ) ( struct iscsi_session *iscsi, const char *value );
};
/** iSCSI text strings that we want to handle */
struct iscsi_string_type iscsi_string_types[] = {
{ "TargetAddress=", iscsi_handle_targetaddress_value },
{ "AuthMethod=", iscsi_handle_authmethod_value },
{ "CHAP_A=", iscsi_handle_chap_a_value },
{ "CHAP_I=", iscsi_handle_chap_i_value },
{ "CHAP_C=", iscsi_handle_chap_c_value },
{ NULL, NULL }
};
/**
* Handle iSCSI string
*
* @v iscsi iSCSI session
* @v string iSCSI string (in "key=value" format)
* @ret rc Return status code
*/
static int iscsi_handle_string ( struct iscsi_session *iscsi,
const char *string ) {
struct iscsi_string_type *type;
size_t key_len;
int rc;
for ( type = iscsi_string_types ; type->key ; type++ ) {
key_len = strlen ( type->key );
if ( strncmp ( string, type->key, key_len ) != 0 )
continue;
DBGC ( iscsi, "iSCSI %p handling %s\n", iscsi, string );
if ( ( rc = type->handle ( iscsi,
( string + key_len ) ) ) != 0 ) {
DBGC ( iscsi, "iSCSI %p could not handle %s: %s\n",
iscsi, string, strerror ( rc ) );
return rc;
}
return 0;
}
DBGC ( iscsi, "iSCSI %p ignoring %s\n", iscsi, string );
return 0;
}
/**
* Handle iSCSI strings
*
* @v iscsi iSCSI session
* @v string iSCSI string buffer
* @v len Length of string buffer
* @ret rc Return status code
*/
static int iscsi_handle_strings ( struct iscsi_session *iscsi,
const char *strings, size_t len ) {
size_t string_len;
int rc;
/* Handle each string in turn, taking care not to overrun the
* data buffer in case of badly-terminated data.
*/
while ( 1 ) {
string_len = ( strnlen ( strings, len ) + 1 );
if ( string_len > len )
break;
if ( ( rc = iscsi_handle_string ( iscsi, strings ) ) != 0 )
return rc;
strings += string_len;
len -= string_len;
}
return 0;
}
/**
* Receive PDU data into buffer
*
* @v iscsi iSCSI session
* @v data Data to receive
* @v len Length of data
* @ret rc Return status code
*
* This can be used when the RX PDU type handler wishes to buffer up
* all received data and process the PDU as a single unit. The caller
* is repsonsible for calling iscsi_rx_buffered_data_done() after
* processing the data.
*/
static int iscsi_rx_buffered_data ( struct iscsi_session *iscsi,
const void *data, size_t len ) {
/* Allocate buffer on first call */
if ( ! iscsi->rx_buffer ) {
iscsi->rx_buffer = malloc ( iscsi->rx_len );
if ( ! iscsi->rx_buffer )
return -ENOMEM;
}
/* Copy data to buffer */
assert ( ( iscsi->rx_offset + len ) <= iscsi->rx_len );
memcpy ( ( iscsi->rx_buffer + iscsi->rx_offset ), data, len );
return 0;
}
/**
* 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
* @ret rc Return status code
*/
static int iscsi_rx_login_response ( struct iscsi_session *iscsi,
const void *data, size_t len,
size_t remaining ) {
struct iscsi_bhs_login_response *response
= &iscsi->rx_bhs.login_response;
int rc;
/* Buffer up the PDU data */
if ( ( rc = iscsi_rx_buffered_data ( iscsi, data, len ) ) != 0 ) {
DBGC ( iscsi, "iSCSI %p could not buffer login response: %s\n",
iscsi, strerror ( rc ) );
return rc;
}
if ( remaining )
return 0;
/* Process string data and discard string buffer */
if ( ( rc = iscsi_handle_strings ( iscsi, iscsi->rx_buffer,
iscsi->rx_len ) ) != 0 )
return rc;
iscsi_rx_buffered_data_done ( iscsi );
/* Check for login redirection */
if ( response->status_class == ISCSI_STATUS_REDIRECT ) {
DBGC ( iscsi, "iSCSI %p redirecting to new server\n", iscsi );
iscsi_close_connection ( iscsi, 0 );
if ( ( rc = iscsi_open_connection ( iscsi ) ) != 0 ) {
DBGC ( iscsi, "iSCSI %p could not redirect: %s\n ",
iscsi, strerror ( rc ) );
return rc;
}
return 0;
}
/* Check for fatal errors */
if ( response->status_class != 0 ) {
DBGC ( iscsi, "iSCSI login failure: class %02x detail %02x\n",
response->status_class, response->status_detail );
iscsi->instant_rc = -EPERM;
return -EPERM;
}
/* Handle login transitions */
if ( response->flags & ISCSI_LOGIN_FLAG_TRANSITION ) {
switch ( response->flags & ISCSI_LOGIN_NSG_MASK ) {
case ISCSI_LOGIN_NSG_OPERATIONAL_NEGOTIATION:
iscsi->status =
( ISCSI_STATUS_OPERATIONAL_NEGOTIATION_PHASE |
ISCSI_STATUS_STRINGS_OPERATIONAL );
break;
case ISCSI_LOGIN_NSG_FULL_FEATURE_PHASE:
iscsi->status = ISCSI_STATUS_FULL_FEATURE_PHASE;
break;
default:
DBGC ( iscsi, "iSCSI %p got invalid response flags "
"%02x\n", iscsi, response->flags );
return -EIO;
}
}
/* Send next login request PDU if we haven't reached the full
* feature phase yet.
*/
if ( ( iscsi->status & ISCSI_STATUS_PHASE_MASK ) !=
ISCSI_STATUS_FULL_FEATURE_PHASE ) {
iscsi_start_login ( iscsi );
return 0;
}
/* Reset retry count */
iscsi->retry_count = 0;
/* Record TSIH for future reference */
iscsi->tsih = ntohl ( response->tsih );
/* Send the actual SCSI command */
iscsi_start_command ( iscsi );
return 0;
}
/****************************************************************************
*
* iSCSI to socket interface
*
*/
/**
* 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 ) );
/* Flag TX engine to start transmitting */
iscsi->tx_state = ISCSI_TX_BHS;
}
/**
* Transmit basic header segment of an iSCSI PDU
*
* @v iscsi iSCSI session
* @ret rc Return status code
*/
static int iscsi_tx_bhs ( struct iscsi_session *iscsi ) {
return xfer_deliver_raw ( &iscsi->socket, &iscsi->tx_bhs,
sizeof ( iscsi->tx_bhs ) );
}
/**
* Transmit data segment of an iSCSI PDU
*
* @v iscsi iSCSI session
* @ret rc Return status code
*
* Handle transmission of part of a PDU data segment. iscsi::tx_bhs
* will be valid when this is called.
*/
static int 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_DATA_OUT:
return iscsi_tx_data_out ( iscsi );
case ISCSI_OPCODE_LOGIN_REQUEST:
return iscsi_tx_login_request ( iscsi );
default:
assert ( 0 );
return -EINVAL;
}
}
/**
* Transmit data padding of an iSCSI PDU
*
* @v iscsi iSCSI session
* @ret rc Return status code
*
* Handle transmission of any data padding in a PDU data segment.
* iscsi::tx_bhs will be valid when this is called.
*/
static int iscsi_tx_data_padding ( struct iscsi_session *iscsi ) {
static const char pad[] = { '\0', '\0', '\0' };
struct iscsi_bhs_common *common = &iscsi->tx_bhs.common;
size_t pad_len;
pad_len = ISCSI_DATA_PAD_LEN ( common->lengths );
if ( ! pad_len )
return 0;
return xfer_deliver_raw ( &iscsi->socket, pad, pad_len );
}
/**
* 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 );
case ISCSI_OPCODE_LOGIN_REQUEST:
iscsi_login_request_done ( iscsi );
default:
/* No action */
break;
}
}
/**
* Transmit iSCSI PDU
*
* @v iscsi iSCSI session
* @v buf Temporary data buffer
* @v len Length of temporary data buffer
*
* Constructs data to be sent for the current TX state
*/
static void iscsi_tx_step ( struct process *process ) {
struct iscsi_session *iscsi =
container_of ( process, struct iscsi_session, process );
int rc = 0;
if ( xfer_window ( &iscsi->socket ) == 0 )
return;
switch ( iscsi->tx_state ) {
case ISCSI_TX_IDLE:
/* Nothing to send */
break;
case ISCSI_TX_BHS:
if ( ( rc = iscsi_tx_bhs ( iscsi ) ) != 0 )
break;
iscsi->tx_state = ISCSI_TX_AHS;
break;
case ISCSI_TX_AHS:
/* We don't yet have an AHS transmission mechanism */
iscsi->tx_state = ISCSI_TX_DATA;
break;
case ISCSI_TX_DATA:
if ( ( rc = iscsi_tx_data ( iscsi ) ) != 0 )
break;
iscsi->tx_state = ISCSI_TX_DATA_PADDING;
break;
case ISCSI_TX_DATA_PADDING:
if ( ( rc = iscsi_tx_data_padding ( iscsi ) ) != 0 )
break;
iscsi->tx_state = ISCSI_TX_IDLE;
iscsi_tx_done ( iscsi );
break;
default:
assert ( 0 );
break;
}
}
/**
* 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
* @ret rc Return status code
*
* This fills in iscsi::rx_bhs with the data from the BHS portion of
* the received PDU.
*/
static int iscsi_rx_bhs ( struct iscsi_session *iscsi, const void *data,
size_t len, size_t remaining __unused ) {
memcpy ( &iscsi->rx_bhs.bytes[iscsi->rx_offset], data, len );
if ( ( iscsi->rx_offset + len ) >= sizeof ( iscsi->rx_bhs ) ) {
DBGC ( iscsi, "iSCSI %p received PDU opcode %#x len %#lx\n",
iscsi, iscsi->rx_bhs.common.opcode,
ISCSI_DATA_LEN ( iscsi->rx_bhs.common.lengths ) );
}
return 0;
}
/**
* 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
* @ret rc Return status code
*
* This discards data from a portion of a received PDU.
*/
static int iscsi_rx_discard ( struct iscsi_session *iscsi __unused,
const void *data __unused, size_t len __unused,
size_t remaining __unused ) {
/* Do nothing */
return 0;
}
/**
* 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
* @ret rc Return status code
*
* Handle processing of part of a PDU data segment. iscsi::rx_bhs
* will be valid when this is called.
*/
static int iscsi_rx_data ( struct iscsi_session *iscsi, const 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 );
switch ( response->opcode & ISCSI_OPCODE_MASK ) {
case ISCSI_OPCODE_LOGIN_RESPONSE:
return iscsi_rx_login_response ( iscsi, data, len, remaining );
case ISCSI_OPCODE_SCSI_RESPONSE:
return iscsi_rx_scsi_response ( iscsi, data, len, remaining );
case ISCSI_OPCODE_DATA_IN:
return iscsi_rx_data_in ( iscsi, data, len, remaining );
case ISCSI_OPCODE_R2T:
return iscsi_rx_r2t ( iscsi, data, len, remaining );
default:
if ( remaining )
return 0;
DBGC ( iscsi, "iSCSI %p unknown opcode %02x\n", iscsi,
response->opcode );
return -EOPNOTSUPP;
}
}
/**
* Receive new data
*
* @v socket Transport layer interface
* @v data Received data
* @v len Length of received data
* @ret rc Return status code
*
* 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 int iscsi_socket_deliver_raw ( struct xfer_interface *socket,
const void *data, size_t len ) {
struct iscsi_session *iscsi =
container_of ( socket, struct iscsi_session, socket );
struct iscsi_bhs_common *common = &iscsi->rx_bhs.common;
int ( *process ) ( struct iscsi_session *iscsi, const void *data,
size_t len, size_t remaining );
enum iscsi_rx_state next_state;
size_t frag_len;
size_t remaining;
int rc;
while ( 1 ) {
switch ( iscsi->rx_state ) {
case ISCSI_RX_BHS:
process = iscsi_rx_bhs;
iscsi->rx_len = sizeof ( iscsi->rx_bhs );
next_state = ISCSI_RX_AHS;
break;
case ISCSI_RX_AHS:
process = iscsi_rx_discard;
iscsi->rx_len = 4 * ISCSI_AHS_LEN ( common->lengths );
next_state = ISCSI_RX_DATA;
break;
case ISCSI_RX_DATA:
process = iscsi_rx_data;
iscsi->rx_len = ISCSI_DATA_LEN ( common->lengths );
next_state = ISCSI_RX_DATA_PADDING;
break;
case ISCSI_RX_DATA_PADDING:
process = iscsi_rx_discard;
iscsi->rx_len = ISCSI_DATA_PAD_LEN ( common->lengths );
next_state = ISCSI_RX_BHS;
break;
default:
assert ( 0 );
return -EINVAL;
}
frag_len = iscsi->rx_len - iscsi->rx_offset;
if ( frag_len > len )
frag_len = len;
remaining = iscsi->rx_len - iscsi->rx_offset - frag_len;
if ( ( rc = process ( iscsi, data, frag_len,
remaining ) ) != 0 ) {
DBGC ( iscsi, "iSCSI %p could not process received "
"data: %s\n", iscsi, strerror ( rc ) );
iscsi_close_connection ( iscsi, rc );
iscsi_scsi_done ( iscsi, rc );
return rc;
}
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 != iscsi->rx_len )
return 0;
iscsi->rx_state = next_state;
iscsi->rx_offset = 0;
}
return 0;
}
/**
* Handle stream connection closure
*
* @v socket Transport layer interface
* @v rc Reason for close
*
*/
static void iscsi_socket_close ( struct xfer_interface *socket, int rc ) {
struct iscsi_session *iscsi =
container_of ( socket, struct iscsi_session, socket );
/* Even a graceful close counts as an error for iSCSI */
if ( ! rc )
rc = -ECONNRESET;
/* Close session cleanly */
iscsi_close_connection ( iscsi, rc );
/* Retry connection if within the retry limit, otherwise fail */
if ( ++iscsi->retry_count <= ISCSI_MAX_RETRIES ) {
DBGC ( iscsi, "iSCSI %p retrying connection (retry #%d)\n",
iscsi, iscsi->retry_count );
if ( ( rc = iscsi_open_connection ( iscsi ) ) != 0 ) {
DBGC ( iscsi, "iSCSI %p could not reconnect: %s\n",
iscsi, strerror ( rc ) );
iscsi_scsi_done ( iscsi, rc );
}
} else {
DBGC ( iscsi, "iSCSI %p retry count exceeded\n", iscsi );
iscsi->instant_rc = rc;
iscsi_scsi_done ( iscsi, rc );
}
}
/** iSCSI socket operations */
static struct xfer_interface_operations iscsi_socket_operations = {
.close = iscsi_socket_close,
.vredirect = xfer_vopen,
.seek = ignore_xfer_seek,
.window = unlimited_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = xfer_deliver_as_raw,
.deliver_raw = iscsi_socket_deliver_raw,
};
/**
* Issue SCSI command via iSCSI session
*
* @v iscsi iSCSI session
* @v command SCSI command
* @v parent Parent asynchronous operation
* @ret rc Return status code
*/
int iscsi_issue ( struct iscsi_session *iscsi, struct scsi_command *command,
struct async *parent ) {
int rc;
assert ( iscsi->command == NULL );
iscsi->command = command;
if ( iscsi->instant_rc ) {
/* Abort immediately rather than retrying */
return iscsi->instant_rc;
} else if ( iscsi->status ) {
/* Session already open: issue command */
iscsi_start_command ( iscsi );
stream_kick ( &iscsi->stream );
} else {
/* Session not open: initiate login */
iscsi->stream.op = &iscsi_stream_operations;
if ( ( rc = tcp_open ( &iscsi->stream ) ) != 0 ) {
DBGC ( iscsi, "iSCSI %p could not open stream: %s\n ",
iscsi, strerror ( rc ) );
return rc;
}
if ( ( rc = stream_connect ( &iscsi->stream,
&iscsi->target ) ) != 0 ) {
DBGC ( iscsi, "iSCSI %p could not connect: %s\n",
iscsi, strerror ( rc ) );
return rc;
}
}
async_init ( &iscsi->async, &default_async_operations, parent );
return 0;
}
/**
* Close down iSCSI session
*
* @v iscsi iSCSI session
* @ret aop Asynchronous operation
*/
void iscsi_shutdown ( struct iscsi_session *iscsi ) {
iscsi_close_connection ( iscsi, 0 );
ref_put ( &iscsi->refcnt );
}
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