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Remove the concept of the media-independent link-layer header and replace

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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.
This commit is contained in:
Michael Brown
2006-04-19 11:32:24 +00:00
parent b89ccac02d
commit bdc8190c8d
6 changed files with 194 additions and 126 deletions
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116
src/net/ethernet.c Normal file
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@@ -0,0 +1,116 @@
/*
* 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_ether.h>
#include <gpxe/netdevice.h>
#include <gpxe/pkbuff.h>
#include <gpxe/arp.h>
/** @file
*
* Ethernet protocol
*
*/
/** Ethernet broadcast MAC address */
static uint8_t eth_broadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
/**
* Build Ethernet link-layer header
*
* @v netdev Network device
* @v pkb Packet buffer
* @ret rc Return status code
*
* This constructs the Ethernet link-layer header (destination MAC,
* source MAC, network-layer protocol) based on the metadata found in
* @c pkb.
*
* If the destination MAC address cannot be determined, an ARP request
* is sent for the requested network-layer address instead.
*/
int eth_build_llh ( struct net_device *netdev, struct pk_buff *pkb ) {
struct ethhdr *ethhdr = pkb->data;
const void *eth_dest;
int rc;
/* Do the easy bits */
ethhdr->h_protocol = pkb->net_proto;
memcpy ( ethhdr->h_source, netdev->ll_addr,
sizeof ( ethhdr->h_source ) );
/* Work out the destination MAC address */
if ( pkb->flags & PKB_FL_RAW_NET_ADDR ) {
eth_dest = pkb->net_addr;
} else if ( pkb->flags & PKB_FL_BROADCAST ) {
eth_dest = eth_broadcast;
} else if ( pkb->flags & PKB_FL_MULTICAST ) {
/* IP multicast is a special case; there exists a
* direct mapping from IP address to MAC address
*/
assert ( pkb->net_proto == htons ( ETH_P_IP ) );
ethhdr->h_dest[0] = 0x01;
ethhdr->h_dest[1] = 0x00;
ethhdr->h_dest[2] = 0x5e;
ethhdr->h_dest[3] = *( ( char * ) pkb->net_addr + 1 ) & 0x7f;
ethhdr->h_dest[4] = *( ( char * ) pkb->net_addr + 2 );
ethhdr->h_dest[5] = *( ( char * ) pkb->net_addr + 3 );
eth_dest = ethhdr->h_dest;
} else {
/* Otherwise, look up the address using ARP */
if ( ( rc = arp_resolve ( netdev, pkb, &eth_dest ) ) != 0 )
return rc;
}
/* Fill in destination MAC address */
memcpy ( ethhdr->h_dest, eth_dest, sizeof ( ethhdr->h_dest ) );
return 0;
}
/**
* Parse Ethernet link-layer header
*
* @v netdev Network device
* @v pkb Packet buffer
* @ret rc Return status code
*
* This parses the Ethernet link-layer header (destination MAC, source
* MAC, network-layer protocol) and fills in the metadata in @c pkb.
*/
int eth_parse_llh ( struct net_device *netdev __unused, struct pk_buff *pkb ) {
struct ethhdr *ethhdr = pkb->data;
pkb->net_proto = ethhdr->h_protocol;
pkb->flags = PKB_FL_RAW_NET_ADDR;
pkb->net_addr_len = sizeof ( ethhdr->h_dest );
pkb->net_addr = ethhdr->h_dest;
if ( memcmp ( ethhdr->h_dest, eth_broadcast,
sizeof ( ethhdr->h_dest ) ) == 0 ) {
pkb->flags |= PKB_FL_BROADCAST;
} else if ( ethhdr->h_dest[0] & 0x01 ) {
pkb->flags |= PKB_FL_MULTICAST;
}
return 0;
}