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fdc2ee79db
implementation allows for only one, and does so without compromising on the efficiency of static allocation). Link-layer protocols are cleanly separated from the device drivers. Network-layer protocols are cleanly separated from individual network devices. Link-layer and network-layer protocols are cleanly separated from each other.
138 lines
4.1 KiB
C
138 lines
4.1 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_arp.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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#include <gpxe/ethernet.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[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
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/**
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* Perform Ethernet routing
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*
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* @v nethdr Generic network-layer header
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* @ret llhdr Generic link-layer header
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* @ret rc Return status code
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*
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* Constructs the generic link-layer header based on the generic
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* network-layer header, i.e. maps network-layer addresses (e.g. IPv4
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* addresses) to MAC addresses.
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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 and -ENOENT is
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* returned.
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*/
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static int eth_route ( const struct net_header *nethdr,
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struct ll_header *llhdr ) {
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int rc;
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/* Work out the destination MAC address */
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if ( nethdr->dest_flags & NETADDR_FL_RAW ) {
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memcpy ( llhdr->dest_ll_addr, nethdr->dest_net_addr, ETH_ALEN);
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} else if ( nethdr->dest_flags & NETADDR_FL_BROADCAST ) {
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memcpy ( llhdr->dest_ll_addr, eth_broadcast, ETH_ALEN );
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} else if ( nethdr->dest_flags & NETADDR_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 ( nethdr->net_protocol->net_proto == htons(ETH_P_IP) );
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llhdr->dest_ll_addr[0] = 0x01;
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llhdr->dest_ll_addr[1] = 0x00;
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llhdr->dest_ll_addr[2] = 0x5e;
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llhdr->dest_ll_addr[3] = nethdr->dest_net_addr[1] & 0x7f;
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llhdr->dest_ll_addr[4] = nethdr->dest_net_addr[2];
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llhdr->dest_ll_addr[5] = nethdr->dest_net_addr[3];
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} else {
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/* Otherwise, look up the address using ARP */
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if ( ( rc = arp_resolve ( nethdr, llhdr ) ) != 0 )
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return rc;
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}
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return 0;
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}
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/**
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* Fill in Ethernet link-layer header
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*
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* @v pkb Packet buffer
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* @v llhdr Generic link-layer header
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*
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* Fills in the Ethernet link-layer header in the packet buffer based
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* on information in the generic link-layer header.
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*/
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static void eth_fill_llh ( const struct ll_header *llhdr,
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struct pk_buff *pkb ) {
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struct ethhdr *ethhdr = pkb->data;
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memcpy ( ethhdr->h_dest, llhdr->dest_ll_addr, ETH_ALEN );
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memcpy ( ethhdr->h_source, llhdr->source_ll_addr, ETH_ALEN );
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ethhdr->h_protocol = llhdr->net_proto;
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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 pkb Packet buffer
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* @v llhdr Generic link-layer header
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*
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* Fills in the generic link-layer header based on information in the
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* Ethernet link-layer header in the packet buffer.
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*/
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static void eth_parse_llh ( const struct pk_buff *pkb,
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struct ll_header *llhdr ) {
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struct ethhdr *ethhdr = pkb->data;
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memcpy ( llhdr->dest_ll_addr, ethhdr->h_dest, ETH_ALEN );
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memcpy ( llhdr->source_ll_addr, ethhdr->h_source, ETH_ALEN );
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llhdr->net_proto = ethhdr->h_protocol;
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if ( memcmp ( ethhdr->h_dest, eth_broadcast, ETH_ALEN ) == 0 ) {
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llhdr->dest_flags = NETADDR_FL_BROADCAST;
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} else if ( ethhdr->h_dest[0] & 0x01 ) {
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llhdr->dest_flags = NETADDR_FL_MULTICAST;
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} else {
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llhdr->dest_flags = 0;
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}
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}
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/** Ethernet protocol */
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struct ll_protocol ethernet_protocol = {
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.ll_proto = htons ( ARPHRD_ETHER ),
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.ll_addr_len = ETH_ALEN,
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.ll_header_len = ETH_HLEN,
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.route = eth_route,
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.fill_llh = eth_fill_llh,
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.parse_llh = eth_parse_llh,
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};
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LL_PROTOCOL ( ethernet_protocol );
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