/*
* 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 <stdint.h>
#include <string.h>
#include <byteswap.h>
#include <assert.h>
#include <gpxe/if_arp.h>
#include <gpxe/if_ether.h>
#include <gpxe/netdevice.h>
#include <gpxe/pkbuff.h>
#include <gpxe/arp.h>
#include <gpxe/ethernet.h>
/** @file
*
* Ethernet protocol
*
*/
/** Ethernet broadcast MAC address */
static uint8_t eth_broadcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
/**
* Perform Ethernet routing
*
* @v nethdr Generic network-layer header
* @ret llhdr Generic link-layer header
* @ret rc Return status code
*
* Constructs the generic link-layer header based on the generic
* network-layer header, i.e. maps network-layer addresses (e.g. IPv4
* addresses) to MAC addresses.
*
* If the destination MAC address cannot be determined, an ARP request
* is sent for the requested network-layer address and -ENOENT is
* returned.
*/
static int eth_route ( const struct net_header *nethdr,
struct ll_header *llhdr ) {
int rc;
/* Work out the destination MAC address */
if ( nethdr->dest_flags & NETADDR_FL_RAW ) {
memcpy ( llhdr->dest_ll_addr, nethdr->dest_net_addr, ETH_ALEN);
} else if ( nethdr->dest_flags & NETADDR_FL_BROADCAST ) {
memcpy ( llhdr->dest_ll_addr, eth_broadcast, ETH_ALEN );
} else if ( nethdr->dest_flags & NETADDR_FL_MULTICAST ) {
/* IP multicast is a special case; there exists a
* direct mapping from IP address to MAC address
*/
assert ( nethdr->net_protocol->net_proto == htons(ETH_P_IP) );
llhdr->dest_ll_addr[0] = 0x01;
llhdr->dest_ll_addr[1] = 0x00;
llhdr->dest_ll_addr[2] = 0x5e;
llhdr->dest_ll_addr[3] = nethdr->dest_net_addr[1] & 0x7f;
llhdr->dest_ll_addr[4] = nethdr->dest_net_addr[2];
llhdr->dest_ll_addr[5] = nethdr->dest_net_addr[3];
} else {
/* Otherwise, look up the address using ARP */
if ( ( rc = arp_resolve ( nethdr, llhdr ) ) != 0 )
return rc;
}
return 0;
}
/**
* Fill in Ethernet link-layer header
*
* @v pkb Packet buffer
* @v llhdr Generic link-layer header
*
* Fills in the Ethernet link-layer header in the packet buffer based
* on information in the generic link-layer header.
*/
static void eth_fill_llh ( const struct ll_header *llhdr,
struct pk_buff *pkb ) {
struct ethhdr *ethhdr = pkb->data;
memcpy ( ethhdr->h_dest, llhdr->dest_ll_addr, ETH_ALEN );
memcpy ( ethhdr->h_source, llhdr->source_ll_addr, ETH_ALEN );
ethhdr->h_protocol = llhdr->net_proto;
}
/**
* Parse Ethernet link-layer header
*
* @v pkb Packet buffer
* @v llhdr Generic link-layer header
*
* Fills in the generic link-layer header based on information in the
* Ethernet link-layer header in the packet buffer.
*/
static void eth_parse_llh ( const struct pk_buff *pkb,
struct ll_header *llhdr ) {
struct ethhdr *ethhdr = pkb->data;
memcpy ( llhdr->dest_ll_addr, ethhdr->h_dest, ETH_ALEN );
memcpy ( llhdr->source_ll_addr, ethhdr->h_source, ETH_ALEN );
llhdr->net_proto = ethhdr->h_protocol;
if ( memcmp ( ethhdr->h_dest, eth_broadcast, ETH_ALEN ) == 0 ) {
llhdr->dest_flags = NETADDR_FL_BROADCAST;
} else if ( ethhdr->h_dest[0] & 0x01 ) {
llhdr->dest_flags = NETADDR_FL_MULTICAST;
} else {
llhdr->dest_flags = 0;
}
}
/** Ethernet protocol */
struct ll_protocol ethernet_protocol = {
.ll_proto = htons ( ARPHRD_ETHER ),
.ll_addr_len = ETH_ALEN,
.ll_header_len = ETH_HLEN,
.route = eth_route,
.fill_llh = eth_fill_llh,
.parse_llh = eth_parse_llh,
};
LL_PROTOCOL ( ethernet_protocol );
