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bdc8190c8d
it with metadata in the pkb structure. This is required since UNDI will want to be able to parse the link-layer header without destroying it.
117 lines
3.4 KiB
C
117 lines
3.4 KiB
C
/*
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* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <stdint.h>
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#include <string.h>
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#include <byteswap.h>
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#include <assert.h>
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#include <gpxe/if_ether.h>
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#include <gpxe/netdevice.h>
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#include <gpxe/pkbuff.h>
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#include <gpxe/arp.h>
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/** @file
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*
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* Ethernet protocol
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*
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*/
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/** Ethernet broadcast MAC address */
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static uint8_t eth_broadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
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/**
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* Build Ethernet link-layer header
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*
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* @v netdev Network device
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* @v pkb Packet buffer
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* @ret rc Return status code
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*
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* This constructs the Ethernet link-layer header (destination MAC,
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* source MAC, network-layer protocol) based on the metadata found in
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* @c pkb.
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*
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* If the destination MAC address cannot be determined, an ARP request
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* is sent for the requested network-layer address instead.
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*/
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int eth_build_llh ( struct net_device *netdev, struct pk_buff *pkb ) {
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struct ethhdr *ethhdr = pkb->data;
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const void *eth_dest;
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int rc;
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/* Do the easy bits */
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ethhdr->h_protocol = pkb->net_proto;
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memcpy ( ethhdr->h_source, netdev->ll_addr,
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sizeof ( ethhdr->h_source ) );
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/* Work out the destination MAC address */
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if ( pkb->flags & PKB_FL_RAW_NET_ADDR ) {
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eth_dest = pkb->net_addr;
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} else if ( pkb->flags & PKB_FL_BROADCAST ) {
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eth_dest = eth_broadcast;
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} else if ( pkb->flags & PKB_FL_MULTICAST ) {
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/* IP multicast is a special case; there exists a
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* direct mapping from IP address to MAC address
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*/
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assert ( pkb->net_proto == htons ( ETH_P_IP ) );
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ethhdr->h_dest[0] = 0x01;
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ethhdr->h_dest[1] = 0x00;
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ethhdr->h_dest[2] = 0x5e;
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ethhdr->h_dest[3] = *( ( char * ) pkb->net_addr + 1 ) & 0x7f;
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ethhdr->h_dest[4] = *( ( char * ) pkb->net_addr + 2 );
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ethhdr->h_dest[5] = *( ( char * ) pkb->net_addr + 3 );
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eth_dest = ethhdr->h_dest;
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} else {
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/* Otherwise, look up the address using ARP */
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if ( ( rc = arp_resolve ( netdev, pkb, ð_dest ) ) != 0 )
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return rc;
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}
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/* Fill in destination MAC address */
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memcpy ( ethhdr->h_dest, eth_dest, sizeof ( ethhdr->h_dest ) );
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return 0;
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}
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/**
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* Parse Ethernet link-layer header
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*
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* @v netdev Network device
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* @v pkb Packet buffer
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* @ret rc Return status code
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*
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* This parses the Ethernet link-layer header (destination MAC, source
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* MAC, network-layer protocol) and fills in the metadata in @c pkb.
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*/
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int eth_parse_llh ( struct net_device *netdev __unused, struct pk_buff *pkb ) {
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struct ethhdr *ethhdr = pkb->data;
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pkb->net_proto = ethhdr->h_protocol;
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pkb->flags = PKB_FL_RAW_NET_ADDR;
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pkb->net_addr_len = sizeof ( ethhdr->h_dest );
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pkb->net_addr = ethhdr->h_dest;
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if ( memcmp ( ethhdr->h_dest, eth_broadcast,
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sizeof ( ethhdr->h_dest ) ) == 0 ) {
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pkb->flags |= PKB_FL_BROADCAST;
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} else if ( ethhdr->h_dest[0] & 0x01 ) {
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pkb->flags |= PKB_FL_MULTICAST;
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}
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return 0;
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}
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