2 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20 FILE_LICENCE ( GPL2_OR_LATER );
27 #include <ipxe/if_ether.h>
28 #include <ipxe/if_arp.h>
29 #include <ipxe/iobuf.h>
30 #include <ipxe/netdevice.h>
31 #include <ipxe/neighbour.h>
36 * Address Resolution Protocol
38 * This file implements the address resolution protocol as defined in
39 * RFC826. The implementation is media-independent and
40 * protocol-independent; it is not limited to Ethernet or to IPv4.
44 struct net_protocol arp_protocol __net_protocol;
47 * Transmit ARP request
49 * @v netdev Network device
50 * @v net_protocol Network-layer protocol
51 * @v net_dest Destination network-layer address
52 * @v net_source Source network-layer address
53 * @ret rc Return status code
55 static int arp_tx_request ( struct net_device *netdev,
56 struct net_protocol *net_protocol,
57 const void *net_dest, const void *net_source ) {
58 struct ll_protocol *ll_protocol = netdev->ll_protocol;
59 struct io_buffer *iobuf;
60 struct arphdr *arphdr;
63 /* Allocate ARP packet */
64 iobuf = alloc_iob ( MAX_LL_HEADER_LEN + sizeof ( *arphdr ) +
65 ( 2 * ( MAX_LL_ADDR_LEN + MAX_NET_ADDR_LEN ) ) );
68 iob_reserve ( iobuf, MAX_LL_HEADER_LEN );
70 /* Build up ARP request */
71 arphdr = iob_put ( iobuf, sizeof ( *arphdr ) );
72 arphdr->ar_hrd = ll_protocol->ll_proto;
73 arphdr->ar_hln = ll_protocol->ll_addr_len;
74 arphdr->ar_pro = net_protocol->net_proto;
75 arphdr->ar_pln = net_protocol->net_addr_len;
76 arphdr->ar_op = htons ( ARPOP_REQUEST );
77 memcpy ( iob_put ( iobuf, ll_protocol->ll_addr_len ),
78 netdev->ll_addr, ll_protocol->ll_addr_len );
79 memcpy ( iob_put ( iobuf, net_protocol->net_addr_len ),
80 net_source, net_protocol->net_addr_len );
81 memset ( iob_put ( iobuf, ll_protocol->ll_addr_len ),
82 0, ll_protocol->ll_addr_len );
83 memcpy ( iob_put ( iobuf, net_protocol->net_addr_len ),
84 net_dest, net_protocol->net_addr_len );
86 /* Transmit ARP request */
87 if ( ( rc = net_tx ( iobuf, netdev, &arp_protocol,
88 netdev->ll_broadcast, netdev->ll_addr ) ) != 0 ) {
89 DBGC ( netdev, "ARP %s %s %s could not transmit request: %s\n",
90 netdev->name, net_protocol->name,
91 net_protocol->ntoa ( net_dest ), strerror ( rc ) );
98 /** ARP neighbour discovery protocol */
99 struct neighbour_discovery arp_discovery = {
101 .tx_request = arp_tx_request,
105 * Identify ARP protocol
107 * @v net_proto Network-layer protocol, in network-endian order
108 * @ret arp_net_protocol ARP protocol, or NULL
111 static struct arp_net_protocol * arp_find_protocol ( uint16_t net_proto ) {
112 struct arp_net_protocol *arp_net_protocol;
114 for_each_table_entry ( arp_net_protocol, ARP_NET_PROTOCOLS ) {
115 if ( arp_net_protocol->net_protocol->net_proto == net_proto )
116 return arp_net_protocol;
122 * Process incoming ARP packets
124 * @v iobuf I/O buffer
125 * @v netdev Network device
126 * @v ll_source Link-layer source address
127 * @v flags Packet flags
128 * @ret rc Return status code
130 static int arp_rx ( struct io_buffer *iobuf, struct net_device *netdev,
131 const void *ll_dest __unused,
132 const void *ll_source __unused,
133 unsigned int flags __unused ) {
134 struct arphdr *arphdr = iobuf->data;
135 struct arp_net_protocol *arp_net_protocol;
136 struct net_protocol *net_protocol;
137 struct ll_protocol *ll_protocol;
140 /* Identify network-layer and link-layer protocols */
141 arp_net_protocol = arp_find_protocol ( arphdr->ar_pro );
142 if ( ! arp_net_protocol ) {
143 rc = -EPROTONOSUPPORT;
146 net_protocol = arp_net_protocol->net_protocol;
147 ll_protocol = netdev->ll_protocol;
150 if ( ( arphdr->ar_hrd != ll_protocol->ll_proto ) ||
151 ( arphdr->ar_hln != ll_protocol->ll_addr_len ) ||
152 ( arphdr->ar_pln != net_protocol->net_addr_len ) ) {
157 /* Update neighbour cache entry for this sender, if any */
158 neighbour_update ( netdev, net_protocol, arp_sender_pa ( arphdr ),
159 arp_sender_ha ( arphdr ) );
161 /* If it's not a request, there's nothing more to do */
162 if ( arphdr->ar_op != htons ( ARPOP_REQUEST ) ) {
167 /* See if we own the target protocol address */
168 if ( arp_net_protocol->check ( netdev, arp_target_pa ( arphdr ) ) != 0){
173 /* Change request to a reply */
174 DBGC2 ( netdev, "ARP %s %s %s reply => %s %s\n",
175 netdev->name, net_protocol->name,
176 net_protocol->ntoa ( arp_target_pa ( arphdr ) ),
177 ll_protocol->name, ll_protocol->ntoa ( netdev->ll_addr ) );
178 arphdr->ar_op = htons ( ARPOP_REPLY );
179 memswap ( arp_sender_ha ( arphdr ), arp_target_ha ( arphdr ),
180 arphdr->ar_hln + arphdr->ar_pln );
181 memcpy ( arp_sender_ha ( arphdr ), netdev->ll_addr, arphdr->ar_hln );
184 if ( ( rc = net_tx ( iob_disown ( iobuf ), netdev, &arp_protocol,
185 arp_target_ha ( arphdr ),
186 netdev->ll_addr ) ) != 0 ) {
187 DBGC ( netdev, "ARP %s %s %s could not transmit reply: %s\n",
188 netdev->name, net_protocol->name,
189 net_protocol->ntoa ( arp_target_pa ( arphdr ) ),
203 * Transcribe ARP address
205 * @v net_addr ARP address
206 * @ret string "<ARP>"
208 * This operation is meaningless for the ARP protocol.
210 static const char * arp_ntoa ( const void *net_addr __unused ) {
214 /** ARP network protocol */
215 struct net_protocol arp_protocol __net_protocol = {
217 .net_proto = htons ( ETH_P_ARP ),