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7c0a069f42
ipxe/src/net/tcp/iscsi.c
Michael Brown 6d32f0e6e2 Changed to use the generic stream API.
2007-01-31 02:09:13 +00:00

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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/scsi.h>
#include <gpxe/process.h>
#include <gpxe/uaccess.h>
#include <gpxe/tcp.h>
#include <gpxe/iscsi.h>
/** @file
*
* iSCSI protocol
*
*/
static void iscsi_start_tx ( struct iscsi_session *iscsi );
static void iscsi_start_data_out ( struct iscsi_session *iscsi,
unsigned int datasn );
/**
* 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;
}
/**
* 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;
}
/**
* Close iSCSI connection
*
* @v iscsi iSCSI session
*/
static void iscsi_close ( struct iscsi_session *iscsi ) {
/* Close stream connection */
stream_close ( &iscsi->stream );
/* 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 dynamically allocated memory */
chap_finish ( &iscsi->chap );
iscsi_rx_buffered_data_done ( iscsi );
}
/**
* Mark iSCSI operation as complete
*
* @v iscsi iSCSI session
* @v rc Return status code
*
* Note that iscsi_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_done() only at
* the end of receiving a PDU; at this point the TX and RX engines
* should both be idle.
*/
static void iscsi_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
*
*/
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 */
if ( response->response == ISCSI_RESPONSE_COMMAND_COMPLETE ) {
iscsi_done ( iscsi, 0 );
} else {
iscsi_done ( iscsi, -EIO );
}
}
/**
* 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 __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_done ( iscsi, 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
*
*/
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 );
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
* @v buf Temporary data buffer
* @v len Length of temporary data buffer
*/
static void iscsi_tx_data_out ( struct iscsi_session *iscsi,
void *buf, size_t len ) {
struct iscsi_bhs_data_out *data_out = &iscsi->tx_bhs.data_out;
unsigned long offset;
unsigned long remaining;
offset = ( iscsi->transfer_offset + ntohl ( data_out->offset ) +
iscsi->tx_offset );
remaining = ( iscsi->tx_len - iscsi->tx_offset );
assert ( iscsi->command != NULL );
assert ( iscsi->command->data_out );
assert ( ( offset + remaining ) <= iscsi->command->data_out_len );
if ( remaining < len )
len = remaining;
copy_from_user ( buf, iscsi->command->data_out, offset, len );
stream_send ( &iscsi->stream, buf, len );
}
/****************************************************************************
*
* iSCSI login
*
*/
/**
* Version of snprintf() that accepts a signed buffer size
*
* @v buf Buffer into which to write the string
* @v size Size of buffer
* @v fmt Format string
* @v args Arguments corresponding to the format string
* @ret len Length of formatted string
*
* This is a utility function for iscsi_build_login_request_strings().
*/
static int ssnprintf ( char *buf, ssize_t ssize, const char *fmt, ... ) {
va_list args;
int len;
/* Treat negative buffer size as zero buffer size */
if ( ssize < 0 )
ssize = 0;
/* Hand off to vsnprintf */
va_start ( args, fmt );
len = vsnprintf ( buf, ssize, fmt, args );
va_end ( args );
return len;
}
/**
* 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
* @v buf Temporary data buffer
* @v len Length of temporary data buffer
*
* For login requests, the data segment consists of the login strings.
*/
static void iscsi_tx_login_request ( struct iscsi_session *iscsi,
void *buf, size_t len ) {
len = iscsi_build_login_request_strings ( iscsi, buf, len );
stream_send ( &iscsi->stream, buf + iscsi->tx_offset,
len - iscsi->tx_offset );
}
/**
* Handle iSCSI TargetAddress text value
*
* @v iscsi iSCSI session
* @v value TargetAddress value
*/
static void iscsi_handle_targetaddress_value ( struct iscsi_session *iscsi,
const char *value ) {
struct in_addr address;
struct sockaddr_in *sin = ( struct sockaddr_in * ) &iscsi->target;
if ( inet_aton ( value, &address ) == 0 ) {
DBGC ( iscsi, "iSCSI %p received invalid TargetAddress "
"\"%s\"\n", iscsi, value );
return;
}
DBGC ( iscsi, "iSCSI %p will redirect to %s\n", iscsi, value );
sin->sin_addr = address;
}
/**
* Handle iSCSI AuthMethod text value
*
* @v iscsi iSCSI session
* @v value AuthMethod value
*/
static void 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;
}
}
/**
* Handle iSCSI CHAP_A text value
*
* @v iscsi iSCSI session
* @v value CHAP_A value
*/
static void 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 );
}
/* 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 ) );
iscsi_close ( iscsi );
iscsi_done ( iscsi, rc );
}
}
/**
* Handle iSCSI CHAP_I text value
*
* @v iscsi iSCSI session
* @v value CHAP_I value
*/
static void 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 );
}
/* 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 ) );
}
}
/**
* Handle iSCSI CHAP_C text value
*
* @v iscsi iSCSI session
* @v value CHAP_C value
*/
static void 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 );
}
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;
}
/** 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
*/
void ( * handle_value ) ( 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)
*/
static void iscsi_handle_string ( struct iscsi_session *iscsi,
const char *string ) {
struct iscsi_string_type *type;
size_t key_len;
for ( type = iscsi_string_types ; type->key ; type++ ) {
key_len = strlen ( type->key );
if ( strncmp ( string, type->key, key_len ) == 0 ) {
DBGC ( iscsi, "iSCSI %p handling %s\n",
iscsi, string );
type->handle_value ( iscsi, ( string + key_len ) );
return;
}
}
DBGC ( iscsi, "iSCSI %p ignoring %s\n", iscsi, string );
}
/**
* Handle iSCSI strings
*
* @v iscsi iSCSI session
* @v string iSCSI string buffer
* @v len Length of string buffer
*/
static void iscsi_handle_strings ( struct iscsi_session *iscsi,
const char *strings, size_t len ) {
size_t string_len;
/* 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;
iscsi_handle_string ( iscsi, strings );
strings += string_len;
len -= string_len;
}
}
/**
* 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,
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 ) );
iscsi_close ( iscsi );
iscsi_done ( iscsi, rc );
return;
}
if ( remaining )
return;
/* Process string data and discard string buffer */
iscsi_handle_strings ( iscsi, iscsi->rx_buffer, iscsi->rx_len );
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 ( iscsi );
if ( ( rc = tcp_open ( &iscsi->stream ) ) != 0 ) {
DBGC ( iscsi, "iSCSI %p could not open stream: %s\n ",
iscsi, strerror ( rc ) );
iscsi_done ( iscsi, rc );
return;
}
if ( ( rc = stream_connect ( &iscsi->stream,
&iscsi->target ) != 0 ) != 0 ) {
DBGC ( iscsi, "iSCSI %p could not connect: %s\n ",
iscsi, strerror ( rc ) );
iscsi_done ( iscsi, rc );
return;
}
return;
}
/* 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;
iscsi_close ( iscsi );
iscsi_done ( iscsi, -EPERM );
return;
}
/* 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 );
iscsi_close ( iscsi );
iscsi_done ( iscsi, -EIO );
return;
}
}
/* 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;
}
/* 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 );
}
/****************************************************************************
*
* iSCSI to stream interface
*
*/
static inline struct iscsi_session *
stream_to_iscsi ( struct stream_application *app ) {
return container_of ( app, struct iscsi_session, stream );
}
/**
* 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;
iscsi->tx_offset = 0;
}
/**
* Transmit data segment of an iSCSI PDU
*
* @v iscsi iSCSI session
* @v buf Temporary data buffer
* @v len Length of temporary data buffer
*
* 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,
void *buf, size_t len ) {
struct iscsi_bhs_common *common = &iscsi->tx_bhs.common;
switch ( common->opcode & ISCSI_OPCODE_MASK ) {
case ISCSI_OPCODE_DATA_OUT:
iscsi_tx_data_out ( iscsi, buf, len );
break;
case ISCSI_OPCODE_LOGIN_REQUEST:
iscsi_tx_login_request ( iscsi, buf, len );
break;
default:
assert ( 0 );
break;
}
}
/**
* 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;
}
}
/**
* Handle stream ACKs
*
* @v iscsi iSCSI session
*
* Updates iscsi->tx_offset and, if applicable, transitions to the
* next TX state.
*/
static void iscsi_acked ( struct stream_application *app, size_t len ) {
struct iscsi_session *iscsi = stream_to_iscsi ( app );
struct iscsi_bhs_common *common = &iscsi->tx_bhs.common;
enum iscsi_tx_state next_state;
iscsi->tx_offset += len;
while ( 1 ) {
switch ( iscsi->tx_state ) {
case ISCSI_TX_BHS:
iscsi->tx_len = sizeof ( iscsi->tx_bhs );
next_state = ISCSI_TX_AHS;
break;
case ISCSI_TX_AHS:
iscsi->tx_len = 4 * ISCSI_AHS_LEN ( common->lengths );
next_state = ISCSI_TX_DATA;
break;
case ISCSI_TX_DATA:
iscsi->tx_len = ISCSI_DATA_LEN ( common->lengths );
next_state = ISCSI_TX_DATA_PADDING;
break;
case ISCSI_TX_DATA_PADDING:
iscsi->tx_len = 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 <= iscsi->tx_len );
/* If the whole of the current portion has not yet
* been acked, stay in this state for now.
*/
if ( iscsi->tx_offset != iscsi->tx_len )
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 );
}
}
/**
* 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_senddata ( struct stream_application *app,
void *buf, size_t len ) {
struct iscsi_session *iscsi = stream_to_iscsi ( app );
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:
stream_send ( app, &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, buf, len );
break;
case ISCSI_TX_DATA_PADDING:
stream_send ( app, 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 );
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:
if ( remaining )
return;
DBGC ( iscsi, "iSCSI %p unknown opcode %02x\n", iscsi,
response->opcode );
iscsi_close ( iscsi );
iscsi_done ( iscsi, -EOPNOTSUPP );
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 );
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 ) );
}
}
/**
* Receive new data
*
* @v stream Stream application
* @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 stream_application *app, void *data,
size_t len ) {
struct iscsi_session *iscsi = stream_to_iscsi ( app );
struct iscsi_bhs_common *common = &iscsi->rx_bhs.common;
void ( *process ) ( struct iscsi_session *iscsi, void *data,
size_t len, size_t remaining );
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;
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;
}
frag_len = iscsi->rx_len - iscsi->rx_offset;
if ( frag_len > len )
frag_len = len;
remaining = iscsi->rx_len - 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 != iscsi->rx_len )
return;
iscsi->rx_state = next_state;
iscsi->rx_offset = 0;
}
}
/**
* Handle stream connection closure
*
* @v app Stream application
* @v status Error code, if any
*
*/
static void iscsi_closed ( struct stream_application *app, int status ) {
struct iscsi_session *iscsi = stream_to_iscsi ( app );
int rc;
/* Even a graceful close counts as an error for iSCSI */
if ( ! status )
status = -ECONNRESET;
/* Close session cleanly */
iscsi_close ( iscsi );
/* 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 = tcp_open ( app ) ) != 0 ) {
DBGC ( iscsi, "iSCSI %p could not open stream: %s\n ",
iscsi, strerror ( rc ) );
iscsi_done ( iscsi, rc );
return;
}
if ( ( rc = stream_connect ( app, &iscsi->target ) ) != 0 ){
DBGC ( iscsi, "iSCSI %p could not connect: %s\n",
iscsi, strerror ( rc ) );
iscsi_done ( iscsi, rc );
return;
}
} else {
DBGC ( iscsi, "iSCSI %p retry count exceeded\n", iscsi );
iscsi->instant_rc = status;
iscsi_done ( iscsi, status );
return;
}
}
/**
* Handle stream connection opening
*
* @v app Stream application
*
*/
static void iscsi_connected ( struct stream_application *app ) {
struct iscsi_session *iscsi = stream_to_iscsi ( app );
assert ( iscsi->rx_state == ISCSI_RX_BHS );
assert ( iscsi->rx_offset == 0 );
/* Enter security negotiation phase */
iscsi->status = ( ISCSI_STATUS_SECURITY_NEGOTIATION_PHASE |
ISCSI_STATUS_STRINGS_SECURITY );
/* Assign fresh initiator task tag */
iscsi->itt++;
/* Start logging in */
iscsi_start_login ( iscsi );
}
/** iSCSI stream operations */
static struct stream_application_operations iscsi_stream_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
* @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 ( iscsi );
}
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