/*
* Copyright (C) 2013 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 );
#include <stdint.h>
#include <stdlib.h>
#include <ipxe/dhcppkt.h>
#include <ipxe/init.h>
#include <ipxe/netdevice.h>
#include <realmode.h>
#include <pxe_api.h>
/** @file
*
* Cached DHCP packet
*
*/
/** Cached DHCPACK physical address
*
* This can be set by the prefix.
*/
uint32_t __bss16 ( cached_dhcpack_phys );
#define cached_dhcpack_phys __use_data16 ( cached_dhcpack_phys )
/** Colour for debug messages */
#define colour &cached_dhcpack_phys
/** Cached DHCPACK */
static struct dhcp_packet *cached_dhcpack;
/**
* Cached DHCPACK startup function
*
*/
static void cachedhcp_init ( void ) {
struct dhcp_packet *dhcppkt;
struct dhcp_packet *tmp;
struct dhcphdr *dhcphdr;
size_t max_len;
size_t len;
/* Do nothing if no cached DHCPACK is present */
if ( ! cached_dhcpack_phys ) {
DBGC ( colour, "CACHEDHCP found no cached DHCPACK\n" );
return;
}
/* No reliable way to determine length before parsing packet;
* start by assuming maximum length permitted by PXE.
*/
max_len = sizeof ( BOOTPLAYER_t );
/* Allocate and populate DHCP packet */
dhcppkt = zalloc ( sizeof ( *dhcppkt ) + max_len );
if ( ! dhcppkt ) {
DBGC ( colour, "CACHEDHCP could not allocate copy\n" );
return;
}
dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( *dhcppkt ) );
copy_from_user ( dhcphdr, phys_to_user ( cached_dhcpack_phys ), 0,
max_len );
dhcppkt_init ( dhcppkt, dhcphdr, max_len );
/* Shrink packet to required length. If reallocation fails,
* just continue to use the original packet and waste the
* unused space.
*/
len = dhcppkt_len ( dhcppkt );
assert ( len <= max_len );
tmp = realloc ( dhcppkt, ( sizeof ( *dhcppkt ) + len ) );
if ( tmp )
dhcppkt = tmp;
/* Reinitialise packet at new address */
dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( *dhcppkt ) );
dhcppkt_init ( dhcppkt, dhcphdr, len );
/* Store as cached DHCPACK, and mark original copy as consumed */
DBGC ( colour, "CACHEDHCP found cached DHCPACK at %08x+%zx\n",
cached_dhcpack_phys, len );
cached_dhcpack = dhcppkt;
cached_dhcpack_phys = 0;
}
/**
* Cached DHCPACK startup function
*
*/
static void cachedhcp_startup ( void ) {
/* If cached DHCP packet was not claimed by any network device
* during startup, then free it.
*/
if ( cached_dhcpack ) {
DBGC ( colour, "CACHEDHCP freeing unclaimed cached DHCPACK\n" );
dhcppkt_put ( cached_dhcpack );
cached_dhcpack = NULL;
}
}
/** Cached DHCPACK initialisation function */
struct init_fn cachedhcp_init_fn __init_fn ( INIT_NORMAL ) = {
.initialise = cachedhcp_init,
};
/** Cached DHCPACK startup function */
struct startup_fn cachedhcp_startup_fn __startup_fn ( STARTUP_LATE ) = {
.name = "cachedhcp",
.startup = cachedhcp_startup,
};
/**
* Apply cached DHCPACK to network device, if applicable
*
* @v netdev Network device
* @ret rc Return status code
*/
static int cachedhcp_probe ( struct net_device *netdev ) {
struct ll_protocol *ll_protocol = netdev->ll_protocol;
int rc;
/* Do nothing unless we have a cached DHCPACK */
if ( ! cached_dhcpack )
return 0;
/* Do nothing unless cached DHCPACK's MAC address matches this
* network device.
*/
if ( memcmp ( netdev->ll_addr, cached_dhcpack->dhcphdr->chaddr,
ll_protocol->ll_addr_len ) != 0 ) {
DBGC ( colour, "CACHEDHCP cached DHCPACK does not match %s\n",
netdev->name );
return 0;
}
DBGC ( colour, "CACHEDHCP cached DHCPACK is for %s\n", netdev->name );
/* Register as DHCP settings for this network device */
if ( ( rc = register_settings ( &cached_dhcpack->settings,
netdev_settings ( netdev ),
DHCP_SETTINGS_NAME ) ) != 0 ) {
DBGC ( colour, "CACHEDHCP could not register settings: %s\n",
strerror ( rc ) );
return rc;
}
/* Claim cached DHCPACK */
dhcppkt_put ( cached_dhcpack );
cached_dhcpack = NULL;
return 0;
}
/** Cached DHCP packet network device driver */
struct net_driver cachedhcp_driver __net_driver = {
.name = "cachedhcp",
.probe = cachedhcp_probe,
};
