/*
* Copyright (C) 2017 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., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
/**
* @file
*
* SAN booting
*
*/
#include <stdint.h>
#include <stdlib.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/xfer.h>
#include <ipxe/open.h>
#include <ipxe/timer.h>
#include <ipxe/process.h>
#include <ipxe/iso9660.h>
#include <ipxe/dhcp.h>
#include <ipxe/settings.h>
#include <ipxe/sanboot.h>
/**
* Default SAN drive number
*
* The drive number is a meaningful concept only in a BIOS
* environment, where it represents the INT13 drive number (0x80 for
* the first hard disk). We retain it in other environments to allow
* for a simple way for iPXE commands to refer to SAN drives.
*/
#define SAN_DEFAULT_DRIVE 0x80
/**
* Timeout for block device commands (in ticks)
*
* Underlying devices should ideally never become totally stuck.
* However, if they do, then the blocking SAN APIs provide no means
* for the caller to cancel the operation, and the machine appears to
* hang. Use an overall timeout for all commands to avoid this
* problem and bounce timeout failures to the caller.
*/
#define SAN_COMMAND_TIMEOUT ( 15 * TICKS_PER_SEC )
/**
* Number of times to retry commands
*
* We may need to retry commands. For example, the underlying
* connection may be closed by the SAN target due to an inactivity
* timeout, or the SAN target may return pointless "error" messages
* such as "SCSI power-on occurred".
*/
#define SAN_COMMAND_MAX_RETRIES 10
/** List of SAN devices */
LIST_HEAD ( san_devices );
/**
* Find SAN device by drive number
*
* @v drive Drive number
* @ret sandev SAN device, or NULL
*/
struct san_device * sandev_find ( unsigned int drive ) {
struct san_device *sandev;
list_for_each_entry ( sandev, &san_devices, list ) {
if ( sandev->drive == drive )
return sandev;
}
return NULL;
}
/**
* Free SAN device
*
* @v refcnt Reference count
*/
static void sandev_free ( struct refcnt *refcnt ) {
struct san_device *sandev =
container_of ( refcnt, struct san_device, refcnt );
assert ( ! timer_running ( &sandev->timer ) );
uri_put ( sandev->uri );
free ( sandev );
}
/**
* Close SAN device command
*
* @v sandev SAN device
* @v rc Reason for close
*/
static void sandev_command_close ( struct san_device *sandev, int rc ) {
/* Stop timer */
stop_timer ( &sandev->timer );
/* Restart interface */
intf_restart ( &sandev->command, rc );
/* Record command status */
sandev->command_rc = rc;
}
/**
* Record SAN device capacity
*
* @v sandev SAN device
* @v capacity SAN device capacity
*/
static void sandev_command_capacity ( struct san_device *sandev,
struct block_device_capacity *capacity ) {
/* Record raw capacity information */
memcpy ( &sandev->capacity, capacity, sizeof ( sandev->capacity ) );
}
/** SAN device command interface operations */
static struct interface_operation sandev_command_op[] = {
INTF_OP ( intf_close, struct san_device *, sandev_command_close ),
INTF_OP ( block_capacity, struct san_device *,
sandev_command_capacity ),
};
/** SAN device command interface descriptor */
static struct interface_descriptor sandev_command_desc =
INTF_DESC ( struct san_device, command, sandev_command_op );
/**
* Handle SAN device command timeout
*
* @v retry Retry timer
*/
static void sandev_command_expired ( struct retry_timer *timer,
int over __unused ) {
struct san_device *sandev =
container_of ( timer, struct san_device, timer );
sandev_command_close ( sandev, -ETIMEDOUT );
}
/**
* Restart SAN device interface
*
* @v sandev SAN device
* @v rc Reason for restart
*/
static void sandev_restart ( struct san_device *sandev, int rc ) {
/* Restart block device interface */
intfs_restart ( rc, &sandev->command, &sandev->block, NULL );
/* Close any outstanding command */
sandev_command_close ( sandev, rc );
/* Record device error */
sandev->block_rc = rc;
}
/**
* (Re)open SAN device
*
* @v sandev SAN device
* @ret rc Return status code
*
* This function will block until the device is available.
*/
int sandev_reopen ( struct san_device *sandev ) {
int rc;
/* Close any outstanding command and restart interface */
sandev_restart ( sandev, -ECONNRESET );
/* Mark device as being not yet open */
sandev->block_rc = -EINPROGRESS;
/* Open block device interface */
if ( ( rc = xfer_open_uri ( &sandev->block, sandev->uri ) ) != 0 ) {
DBGC ( sandev, "SAN %#02x could not (re)open URI: %s\n",
sandev->drive, strerror ( rc ) );
return rc;
}
/* Wait for device to become available */
while ( sandev->block_rc == -EINPROGRESS ) {
step();
if ( xfer_window ( &sandev->block ) != 0 ) {
sandev->block_rc = 0;
return 0;
}
}
DBGC ( sandev, "SAN %#02x never became available: %s\n",
sandev->drive, strerror ( sandev->block_rc ) );
return sandev->block_rc;
}
/**
* Handle closure of underlying block device interface
*
* @v sandev SAN device
* @ret rc Reason for close
*/
static void sandev_block_close ( struct san_device *sandev, int rc ) {
/* Any closure is an error from our point of view */
if ( rc == 0 )
rc = -ENOTCONN;
DBGC ( sandev, "SAN %#02x went away: %s\n",
sandev->drive, strerror ( rc ) );
/* Close any outstanding command and restart interface */
sandev_restart ( sandev, rc );
}
/**
* Check SAN device flow control window
*
* @v sandev SAN device
*/
static size_t sandev_block_window ( struct san_device *sandev __unused ) {
/* We are never ready to receive data via this interface.
* This prevents objects that support both block and stream
* interfaces from attempting to send us stream data.
*/
return 0;
}
/** SAN device block interface operations */
static struct interface_operation sandev_block_op[] = {
INTF_OP ( intf_close, struct san_device *, sandev_block_close ),
INTF_OP ( xfer_window, struct san_device *, sandev_block_window ),
};
/** SAN device block interface descriptor */
static struct interface_descriptor sandev_block_desc =
INTF_DESC ( struct san_device, block, sandev_block_op );
/** SAN device read/write command parameters */
struct san_command_rw_params {
/** SAN device read/write operation */
int ( * block_rw ) ( struct interface *control, struct interface *data,
uint64_t lba, unsigned int count,
userptr_t buffer, size_t len );
/** Data buffer */
userptr_t buffer;
/** Starting LBA */
uint64_t lba;
/** Block count */
unsigned int count;
};
/** SAN device command parameters */
union san_command_params {
/** Read/write command parameters */
struct san_command_rw_params rw;
};
/**
* Initiate SAN device read/write command
*
* @v sandev SAN device
* @v params Command parameters
* @ret rc Return status code
*/
static int sandev_command_rw ( struct san_device *sandev,
const union san_command_params *params ) {
size_t len = ( params->rw.count * sandev->capacity.blksize );
int rc;
/* Initiate read/write command */
if ( ( rc = params->rw.block_rw ( &sandev->block, &sandev->command,
params->rw.lba, params->rw.count,
params->rw.buffer, len ) ) != 0 ) {
DBGC ( sandev, "SAN %#02x could not initiate read/write: "
"%s\n", sandev->drive, strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Initiate SAN device read capacity command
*
* @v sandev SAN device
* @v params Command parameters
* @ret rc Return status code
*/
static int
sandev_command_read_capacity ( struct san_device *sandev,
const union san_command_params *params __unused){
int rc;
/* Initiate read capacity command */
if ( ( rc = block_read_capacity ( &sandev->block,
&sandev->command ) ) != 0 ) {
DBGC ( sandev, "SAN %#02x could not initiate read capacity: "
"%s\n", sandev->drive, strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Execute a single SAN device command and wait for completion
*
* @v sandev SAN device
* @v command Command
* @v params Command parameters (if required)
* @ret rc Return status code
*/
static int
sandev_command ( struct san_device *sandev,
int ( * command ) ( struct san_device *sandev,
const union san_command_params *params ),
const union san_command_params *params ) {
unsigned int retries;
int rc;
/* Sanity check */
assert ( ! timer_running ( &sandev->timer ) );
/* (Re)try command */
for ( retries = 0 ; retries < SAN_COMMAND_MAX_RETRIES ; retries++ ) {
/* Reopen block device if applicable */
if ( sandev_needs_reopen ( sandev ) &&
( ( rc = sandev_reopen ( sandev ) ) != 0 ) ) {
continue;
}
/* Start expiry timer */
start_timer_fixed ( &sandev->timer, SAN_COMMAND_TIMEOUT );
/* Initiate command */
if ( ( rc = command ( sandev, params ) ) != 0 ) {
stop_timer ( &sandev->timer );
continue;
}
/* Wait for command to complete */
while ( timer_running ( &sandev->timer ) )
step();
/* Exit on success */
if ( ( rc = sandev->command_rc ) == 0 )
return 0;
}
/* Sanity check */
assert ( ! timer_running ( &sandev->timer ) );
return rc;
}
/**
* Reset SAN device
*
* @v sandev SAN device
* @ret rc Return status code
*/
int sandev_reset ( struct san_device *sandev ) {
int rc;
DBGC ( sandev, "SAN %#02x reset\n", sandev->drive );
/* Close and reopen underlying block device */
if ( ( rc = sandev_reopen ( sandev ) ) != 0 )
return rc;
return 0;
}
/**
* Read from or write to SAN device
*
* @v sandev SAN device
* @v lba Starting logical block address
* @v count Number of logical blocks
* @v buffer Data buffer
* @v block_rw Block read/write method
* @ret rc Return status code
*/
int sandev_rw ( struct san_device *sandev, uint64_t lba,
unsigned int count, userptr_t buffer,
int ( * block_rw ) ( struct interface *control,
struct interface *data,
uint64_t lba, unsigned int count,
userptr_t buffer, size_t len ) ) {
union san_command_params params;
unsigned int remaining;
size_t frag_len;
int rc;
/* Initialise command parameters */
params.rw.block_rw = block_rw;
params.rw.buffer = buffer;
params.rw.lba = ( lba << sandev->blksize_shift );
params.rw.count = sandev->capacity.max_count;
remaining = ( count << sandev->blksize_shift );
/* Read/write fragments */
while ( remaining ) {
/* Determine fragment length */
if ( params.rw.count > remaining )
params.rw.count = remaining;
/* Execute command */
if ( ( rc = sandev_command ( sandev, sandev_command_rw,
¶ms ) ) != 0 )
return rc;
/* Move to next fragment */
frag_len = ( sandev->capacity.blksize * params.rw.count );
params.rw.buffer = userptr_add ( params.rw.buffer, frag_len );
params.rw.lba += params.rw.count;
remaining -= params.rw.count;
}
return 0;
}
/**
* Configure SAN device as a CD-ROM, if applicable
*
* @v sandev SAN device
* @ret rc Return status code
*
* Both BIOS and UEFI require SAN devices to be accessed with a block
* size of 2048. While we could require the user to configure the
* block size appropriately, this is non-trivial and would impose a
* substantial learning effort on the user. Instead, we check for the
* presence of the ISO9660 primary volume descriptor and, if found,
* then we force a block size of 2048 and map read/write requests
* appropriately.
*/
static int sandev_parse_iso9660 ( struct san_device *sandev ) {
static const struct iso9660_primary_descriptor_fixed primary_check = {
.type = ISO9660_TYPE_PRIMARY,
.id = ISO9660_ID,
};
struct iso9660_primary_descriptor *primary;
unsigned int blksize;
unsigned int blksize_shift;
unsigned int lba;
unsigned int count;
int rc;
/* Calculate required blocksize shift for potential CD-ROM access */
blksize = sandev->capacity.blksize;
blksize_shift = 0;
while ( blksize < ISO9660_BLKSIZE ) {
blksize <<= 1;
blksize_shift++;
}
if ( blksize > ISO9660_BLKSIZE ) {
/* Cannot be a CD-ROM. This is not an error. */
rc = 0;
goto invalid_blksize;
}
lba = ( ISO9660_PRIMARY_LBA << blksize_shift );
count = ( 1 << blksize_shift );
/* Allocate scratch area */
primary = malloc ( ISO9660_BLKSIZE );
if ( ! primary ) {
rc = -ENOMEM;
goto err_alloc;
}
/* Read primary volume descriptor */
if ( ( rc = sandev_rw ( sandev, lba, count, virt_to_user ( primary ),
block_read ) ) != 0 ) {
DBGC ( sandev, "SAN %#02x could not read ISO9660 primary"
"volume descriptor: %s\n",
sandev->drive, strerror ( rc ) );
goto err_rw;
}
/* Configure as CD-ROM if applicable */
if ( memcmp ( primary, &primary_check, sizeof ( primary_check ) ) == 0){
DBGC ( sandev, "SAN %#02x contains an ISO9660 filesystem; "
"treating as CD-ROM\n", sandev->drive );
sandev->blksize_shift = blksize_shift;
sandev->is_cdrom = 1;
}
err_rw:
free ( primary );
err_alloc:
invalid_blksize:
return rc;
}
/**
* Allocate SAN device
*
* @ret sandev SAN device, or NULL
*/
struct san_device * alloc_sandev ( struct uri *uri, size_t priv_size ) {
struct san_device *sandev;
/* Allocate and initialise structure */
sandev = zalloc ( sizeof ( *sandev ) + priv_size );
if ( ! sandev )
return NULL;
ref_init ( &sandev->refcnt, sandev_free );
sandev->uri = uri_get ( uri );
intf_init ( &sandev->block, &sandev_block_desc, &sandev->refcnt );
sandev->block_rc = -EINPROGRESS;
intf_init ( &sandev->command, &sandev_command_desc, &sandev->refcnt );
timer_init ( &sandev->timer, sandev_command_expired, &sandev->refcnt );
sandev->priv = ( ( ( void * ) sandev ) + sizeof ( *sandev ) );
return sandev;
}
/**
* Register SAN device
*
* @v sandev SAN device
* @ret rc Return status code
*/
int register_sandev ( struct san_device *sandev ) {
int rc;
/* Check that drive number is not in use */
if ( sandev_find ( sandev->drive ) != NULL ) {
DBGC ( sandev, "SAN %#02x is already in use\n", sandev->drive );
return -EADDRINUSE;
}
/* Read device capacity */
if ( ( rc = sandev_command ( sandev, sandev_command_read_capacity,
NULL ) ) != 0 )
return rc;
/* Configure as a CD-ROM, if applicable */
if ( ( rc = sandev_parse_iso9660 ( sandev ) ) != 0 )
return rc;
/* Add to list of SAN devices */
list_add_tail ( &sandev->list, &san_devices );
DBGC ( sandev, "SAN %#02x registered\n", sandev->drive );
return 0;
}
/**
* Unregister SAN device
*
* @v sandev SAN device
*/
void unregister_sandev ( struct san_device *sandev ) {
/* Sanity check */
assert ( ! timer_running ( &sandev->timer ) );
/* Shut down interfaces */
intfs_shutdown ( 0, &sandev->block, &sandev->command, NULL );
/* Remove from list of SAN devices */
list_del ( &sandev->list );
DBGC ( sandev, "SAN %#02x unregistered\n", sandev->drive );
}
/** The "san-drive" setting */
const struct setting san_drive_setting __setting ( SETTING_SANBOOT_EXTRA,
san-drive ) = {
.name = "san-drive",
.description = "SAN drive number",
.tag = DHCP_EB_SAN_DRIVE,
.type = &setting_type_uint8,
};
/**
* Get default SAN drive number
*
* @ret drive Default drive number
*/
unsigned int san_default_drive ( void ) {
unsigned long drive;
/* Use "san-drive" setting, if specified */
if ( fetch_uint_setting ( NULL, &san_drive_setting, &drive ) >= 0 )
return drive;
/* Otherwise, default to booting from first hard disk */
return SAN_DEFAULT_DRIVE;
}
