/*
* 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 <errno.h>
#include <ipxe/dhcppkt.h>
#include <ipxe/init.h>
#include <ipxe/netdevice.h>
#include <ipxe/cachedhcp.h>
/** @file
*
* Cached DHCP packet
*
*/
/** A cached DHCP packet */
struct cached_dhcp_packet {
/** Settings block name */
const char *name;
/** DHCP packet (if any) */
struct dhcp_packet *dhcppkt;
};
/** Cached DHCPACK */
struct cached_dhcp_packet cached_dhcpack = {
.name = DHCP_SETTINGS_NAME,
};
/** Cached ProxyDHCPOFFER */
struct cached_dhcp_packet cached_proxydhcp = {
.name = PROXYDHCP_SETTINGS_NAME,
};
/** Cached PXEBSACK */
struct cached_dhcp_packet cached_pxebs = {
.name = PXEBS_SETTINGS_NAME,
};
/** List of cached DHCP packets */
static struct cached_dhcp_packet *cached_packets[] = {
&cached_dhcpack,
&cached_proxydhcp,
&cached_pxebs,
};
/** Colour for debug messages */
#define colour &cached_dhcpack
/**
* Free cached DHCP packet
*
* @v cache Cached DHCP packet
*/
static void cachedhcp_free ( struct cached_dhcp_packet *cache ) {
dhcppkt_put ( cache->dhcppkt );
cache->dhcppkt = NULL;
}
/**
* Apply cached DHCP packet settings
*
* @v cache Cached DHCP packet
* @v netdev Network device, or NULL
* @ret rc Return status code
*/
static int cachedhcp_apply ( struct cached_dhcp_packet *cache,
struct net_device *netdev ) {
struct settings *settings;
int rc;
/* Do nothing if cache is empty */
if ( ! cache->dhcppkt )
return 0;
/* Do nothing unless cached packet's MAC address matches this
* network device, if specified.
*/
if ( netdev ) {
if ( memcmp ( netdev->ll_addr, cache->dhcppkt->dhcphdr->chaddr,
netdev->ll_protocol->ll_addr_len ) != 0 ) {
DBGC ( colour, "CACHEDHCP %s does not match %s\n",
cache->name, netdev->name );
return 0;
}
DBGC ( colour, "CACHEDHCP %s is for %s\n",
cache->name, netdev->name );
}
/* Select appropriate parent settings block */
settings = ( netdev ? netdev_settings ( netdev ) : NULL );
/* Register settings */
if ( ( rc = register_settings ( &cache->dhcppkt->settings, settings,
cache->name ) ) != 0 ) {
DBGC ( colour, "CACHEDHCP %s could not register settings: %s\n",
cache->name, strerror ( rc ) );
return rc;
}
/* Free cached DHCP packet */
cachedhcp_free ( cache );
return 0;
}
/**
* Record cached DHCP packet
*
* @v cache Cached DHCP packet
* @v data DHCPACK packet buffer
* @v max_len Maximum possible length
* @ret rc Return status code
*/
int cachedhcp_record ( struct cached_dhcp_packet *cache, userptr_t data,
size_t max_len ) {
struct dhcp_packet *dhcppkt;
struct dhcp_packet *tmp;
struct dhcphdr *dhcphdr;
unsigned int i;
size_t len;
/* Free any existing cached packet */
cachedhcp_free ( cache );
/* Allocate and populate DHCP packet */
dhcppkt = zalloc ( sizeof ( *dhcppkt ) + max_len );
if ( ! dhcppkt ) {
DBGC ( colour, "CACHEDHCP %s could not allocate copy\n",
cache->name );
return -ENOMEM;
}
dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( *dhcppkt ) );
copy_from_user ( dhcphdr, data, 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 );
/* Discard duplicate packets, since some PXE stacks (including
* iPXE itself) will report the DHCPACK packet as the PXEBSACK
* if no separate PXEBSACK exists.
*/
for ( i = 0 ; i < ( sizeof ( cached_packets ) /
sizeof ( cached_packets[0] ) ) ; i++ ) {
tmp = cached_packets[i]->dhcppkt;
if ( tmp && ( dhcppkt_len ( tmp ) == len ) &&
( memcmp ( tmp->dhcphdr, dhcppkt->dhcphdr, len ) == 0 ) ) {
DBGC ( colour, "CACHEDHCP %s duplicates %s\n",
cache->name, cached_packets[i]->name );
dhcppkt_put ( dhcppkt );
return -EEXIST;
}
}
/* Store as cached packet */
DBGC ( colour, "CACHEDHCP %s at %#08lx+%#zx/%#zx\n", cache->name,
user_to_phys ( data, 0 ), len, max_len );
cache->dhcppkt = dhcppkt;
return 0;
}
/**
* Cached DHCPACK startup function
*
*/
static void cachedhcp_startup ( void ) {
/* Apply cached ProxyDHCPOFFER, if any */
cachedhcp_apply ( &cached_proxydhcp, NULL );
/* Apply cached PXEBSACK, if any */
cachedhcp_apply ( &cached_pxebs, NULL );
/* Free any remaining cached packets */
if ( cached_dhcpack.dhcppkt ) {
DBGC ( colour, "CACHEDHCP %s unclaimed\n",
cached_dhcpack.name );
}
cachedhcp_free ( &cached_dhcpack );
cachedhcp_free ( &cached_proxydhcp );
cachedhcp_free ( &cached_pxebs );
}
/** 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 ) {
/* Apply cached DHCPACK to network device, if applicable */
return cachedhcp_apply ( &cached_dhcpack, netdev );
}
/** Cached DHCP packet network device driver */
struct net_driver cachedhcp_driver __net_driver = {
.name = "cachedhcp",
.probe = cachedhcp_probe,
};
