iPXE
arp.c
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1 /*
2  * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
3  *
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.
8  *
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.
13  *
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
17  * 02110-1301, USA.
18  *
19  * You can also choose to distribute this program under the terms of
20  * the Unmodified Binary Distribution Licence (as given in the file
21  * COPYING.UBDL), provided that you have satisfied its requirements.
22  */
23 
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25 
26 #include <stdint.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <byteswap.h>
30 #include <errno.h>
31 #include <ipxe/if_ether.h>
32 #include <ipxe/if_arp.h>
33 #include <ipxe/iobuf.h>
34 #include <ipxe/netdevice.h>
35 #include <ipxe/neighbour.h>
36 #include <ipxe/arp.h>
37 
38 /** @file
39  *
40  * Address Resolution Protocol
41  *
42  * This file implements the address resolution protocol as defined in
43  * RFC826. The implementation is media-independent and
44  * protocol-independent; it is not limited to Ethernet or to IPv4.
45  *
46  */
47 
48 struct net_protocol arp_protocol __net_protocol;
49 
50 /**
51  * Transmit ARP request
52  *
53  * @v netdev Network device
54  * @v net_protocol Network-layer protocol
55  * @v net_dest Destination network-layer address
56  * @v net_source Source network-layer address
57  * @ret rc Return status code
58  */
60  struct net_protocol *net_protocol,
61  const void *net_dest, const void *net_source ) {
63  struct io_buffer *iobuf;
64  struct arphdr *arphdr;
65  int rc;
66 
67  /* Allocate ARP packet */
68  iobuf = alloc_iob ( MAX_LL_HEADER_LEN + sizeof ( *arphdr ) +
69  ( 2 * ( MAX_LL_ADDR_LEN + MAX_NET_ADDR_LEN ) ) );
70  if ( ! iobuf )
71  return -ENOMEM;
72  iob_reserve ( iobuf, MAX_LL_HEADER_LEN );
73 
74  /* Build up ARP request */
75  arphdr = iob_put ( iobuf, sizeof ( *arphdr ) );
81  memcpy ( iob_put ( iobuf, ll_protocol->ll_addr_len ),
84  net_source, net_protocol->net_addr_len );
85  memset ( iob_put ( iobuf, ll_protocol->ll_addr_len ),
88  net_dest, net_protocol->net_addr_len );
89 
90  /* Transmit ARP request */
91  if ( ( rc = net_tx ( iobuf, netdev, &arp_protocol,
92  netdev->ll_broadcast, netdev->ll_addr ) ) != 0 ) {
93  DBGC ( netdev, "ARP %s %s %s could not transmit request: %s\n",
95  net_protocol->ntoa ( net_dest ), strerror ( rc ) );
96  return rc;
97  }
98 
99  return 0;
100 }
101 
102 /** ARP neighbour discovery protocol */
104  .name = "ARP",
105  .tx_request = arp_tx_request,
106 };
107 
108 /**
109  * Identify ARP protocol
110  *
111  * @v net_proto Network-layer protocol, in network-endian order
112  * @ret arp_net_protocol ARP protocol, or NULL
113  *
114  */
115 static struct arp_net_protocol * arp_find_protocol ( uint16_t net_proto ) {
117 
119  if ( arp_net_protocol->net_protocol->net_proto == net_proto )
120  return arp_net_protocol;
121  }
122  return NULL;
123 }
124 
125 /**
126  * Process incoming ARP packets
127  *
128  * @v iobuf I/O buffer
129  * @v netdev Network device
130  * @v ll_source Link-layer source address
131  * @v flags Packet flags
132  * @ret rc Return status code
133  */
134 static int arp_rx ( struct io_buffer *iobuf, struct net_device *netdev,
135  const void *ll_dest __unused,
136  const void *ll_source __unused,
137  unsigned int flags __unused ) {
138  struct arphdr *arphdr = iobuf->data;
140  struct net_protocol *net_protocol;
141  struct ll_protocol *ll_protocol;
142  size_t len = iob_len ( iobuf );
143  int rc;
144 
145  /* Sanity check */
146  if ( ( len < sizeof ( *arphdr ) ) || ( len < arp_len ( arphdr ) ) ) {
147  rc = -EINVAL;
148  goto done;
149  }
150 
151  /* Identify network-layer and link-layer protocols */
153  if ( ! arp_net_protocol ) {
154  rc = -EPROTONOSUPPORT;
155  goto done;
156  }
159 
160  /* Sanity checks */
161  if ( ( arphdr->ar_hrd != ll_protocol->ll_proto ) ||
164  rc = -EINVAL;
165  goto done;
166  }
167 
168  /* Update neighbour cache entry for this sender, if any */
170  arp_sender_ha ( arphdr ) );
171 
172  /* If it's not a request, there's nothing more to do */
173  if ( arphdr->ar_op != htons ( ARPOP_REQUEST ) ) {
174  rc = 0;
175  goto done;
176  }
177 
178  /* See if we own the target protocol address */
179  if ( arp_net_protocol->check ( netdev, arp_target_pa ( arphdr ) ) != 0){
180  rc = 0;
181  goto done;
182  }
183 
184  /* Change request to a reply */
185  DBGC2 ( netdev, "ARP %s %s %s reply => %s %s\n",
189  arphdr->ar_op = htons ( ARPOP_REPLY );
191  arphdr->ar_hln + arphdr->ar_pln );
193 
194  /* Send reply */
195  if ( ( rc = net_tx ( iob_disown ( iobuf ), netdev, &arp_protocol,
196  arp_target_ha ( arphdr ),
197  netdev->ll_addr ) ) != 0 ) {
198  DBGC ( netdev, "ARP %s %s %s could not transmit reply: %s\n",
201  strerror ( rc ) );
202  goto done;
203  }
204 
205  /* Success */
206  rc = 0;
207 
208  done:
209  free_iob ( iobuf );
210  return rc;
211 }
212 
213 /**
214  * Transcribe ARP address
215  *
216  * @v net_addr ARP address
217  * @ret string "<ARP>"
218  *
219  * This operation is meaningless for the ARP protocol.
220  */
221 static const char * arp_ntoa ( const void *net_addr __unused ) {
222  return "<ARP>";
223 }
224 
225 /** ARP network protocol */
226 struct net_protocol arp_protocol __net_protocol = {
227  .name = "ARP",
228  .net_proto = htons ( ETH_P_ARP ),
229  .rx = arp_rx,
230  .ntoa = arp_ntoa,
231 };
void * memswap(void *first, void *second, size_t len)
Swap memory regions.
Definition: string.c:137
static void * arp_sender_pa(struct arphdr *arphdr)
ARP packet sender protocol address.
Definition: if_arp.h:80
Address Resolution Protocol.
#define EINVAL
Invalid argument.
Definition: errno.h:428
struct arbelprm_rc_send_wqe rc
Definition: arbel.h:14
unsigned short uint16_t
Definition: stdint.h:11
const char * name
Protocol name.
Definition: netdevice.h:66
#define iob_put(iobuf, len)
Definition: iobuf.h:116
const char * name
Name.
Definition: neighbour.h:21
uint8_t ll_addr_len
Link-layer address length.
Definition: netdevice.h:198
static void * arp_target_ha(struct arphdr *arphdr)
ARP packet target hardware address.
Definition: if_arp.h:89
static void * arp_target_pa(struct arphdr *arphdr)
ARP packet target protocol address.
Definition: if_arp.h:98
Error codes.
I/O buffers.
void free_iob(struct io_buffer *iobuf)
Free I/O buffer.
Definition: iobuf.c:145
#define DBGC(...)
Definition: compiler.h:505
A neighbour discovery protocol.
Definition: neighbour.h:19
const uint8_t * ll_broadcast
Link-layer broadcast address.
Definition: netdevice.h:383
uint8_t ar_hln
Link-layer address length.
Definition: if_arp.h:59
int neighbour_update(struct net_device *netdev, struct net_protocol *net_protocol, const void *net_dest, const void *ll_dest)
Update existing neighbour cache entry.
Definition: neighbour.c:338
struct io_buffer * alloc_iob(size_t len)
Allocate I/O buffer.
Definition: iobuf.c:128
A link-layer protocol.
Definition: netdevice.h:114
Address Resolution Protocol constants and types.
uint16_t ar_hrd
Link-layer protocol.
Definition: if_arp.h:52
int(* check)(struct net_device *netdev, const void *net_addr)
Check existence of address.
Definition: arp.h:26
A network-layer protocol that relies upon ARP.
Definition: arp.h:17
const char * name
Protocol name.
Definition: netdevice.h:116
#define ENOMEM
Not enough space.
Definition: errno.h:534
#define iob_disown(iobuf)
Disown an I/O buffer.
Definition: iobuf.h:208
void * memcpy(void *dest, const void *src, size_t len) __nonnull
#define MAX_LL_ADDR_LEN
Maximum length of a link-layer address.
Definition: netdevice.h:36
#define ARPOP_REQUEST
ARP request.
Definition: if_arp.h:32
const char *(* ntoa)(const void *net_addr)
Transcribe network-layer address.
Definition: netdevice.h:94
struct net_protocol * net_protocol
Network-layer protocol.
Definition: arp.h:19
static struct net_device * netdev
Definition: gdbudp.c:52
#define MAX_LL_HEADER_LEN
Maximum length of a link-layer header.
Definition: netdevice.h:45
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)
struct neighbour_discovery arp_discovery
ARP neighbour discovery protocol.
Definition: arp.c:103
static int arp_rx(struct io_buffer *iobuf, struct net_device *netdev, const void *ll_dest __unused, const void *ll_source __unused, unsigned int flags __unused)
Process incoming ARP packets.
Definition: arp.c:134
An ARP header.
Definition: if_arp.h:47
int arp_tx_request(struct net_device *netdev, struct net_protocol *net_protocol, const void *net_dest, const void *net_source)
Transmit ARP request.
Definition: arp.c:59
char * strerror(int errno)
Retrieve string representation of error number.
Definition: strerror.c:78
uint16_t ar_op
ARP opcode.
Definition: if_arp.h:63
static size_t iob_len(struct io_buffer *iobuf)
Calculate length of data in an I/O buffer.
Definition: iobuf.h:151
#define for_each_table_entry(pointer, table)
Iterate through all entries within a linker table.
Definition: tables.h:358
A network device.
Definition: netdevice.h:348
static const char * arp_ntoa(const void *net_addr __unused)
Transcribe ARP address.
Definition: arp.c:221
#define ARPOP_REPLY
ARP reply.
Definition: if_arp.h:33
uint16_t net_proto
Network-layer protocol.
Definition: netdevice.h:99
uint16_t ll_proto
Link-layer protocol.
Definition: netdevice.h:194
static void * arp_sender_ha(struct arphdr *arphdr)
ARP packet sender hardware address.
Definition: if_arp.h:71
A network-layer protocol.
Definition: netdevice.h:64
Network device management.
#define __unused
Declare a variable or data structure as unused.
Definition: compiler.h:573
#define iob_reserve(iobuf, len)
Definition: iobuf.h:63
char name[NETDEV_NAME_LEN]
Name of this network device.
Definition: netdevice.h:358
int net_tx(struct io_buffer *iobuf, struct net_device *netdev, struct net_protocol *net_protocol, const void *ll_dest, const void *ll_source)
Transmit network-layer packet.
Definition: netdevice.c:999
uint32_t len
Length.
Definition: ena.h:14
#define DBGC2(...)
Definition: compiler.h:522
#define EPROTONOSUPPORT
Protocol not supported.
Definition: errno.h:629
uint8_t net_addr_len
Network-layer address length.
Definition: netdevice.h:101
#define ARP_NET_PROTOCOLS
ARP protocol table.
Definition: arp.h:31
Neighbour discovery.
void * data
Start of data.
Definition: iobuf.h:44
uint16_t ar_pro
Network-layer protocol.
Definition: if_arp.h:57
uint8_t ar_pln
Network-layer address length.
Definition: if_arp.h:61
const char *(* ntoa)(const void *ll_addr)
Transcribe link-layer address.
Definition: netdevice.h:163
#define ETH_P_ARP
Definition: if_ether.h:19
struct net_protocol arp_protocol __net_protocol
ARP network protocol.
Definition: arp.c:48
uint8_t ll_addr[MAX_LL_ADDR_LEN]
Link-layer address.
Definition: netdevice.h:381
static struct arp_net_protocol * arp_find_protocol(uint16_t net_proto)
Identify ARP protocol.
Definition: arp.c:115
static size_t arp_len(struct arphdr *arphdr)
ARP packet length.
Definition: if_arp.h:107
#define MAX_NET_ADDR_LEN
Maximum length of a network-layer address.
Definition: netdevice.h:48
#define NULL
NULL pointer (VOID *)
Definition: Base.h:362
String functions.
#define htons(value)
Definition: byteswap.h:135
struct bofm_section_header done
Definition: bofm_test.c:46
struct ll_protocol * ll_protocol
Link-layer protocol.
Definition: netdevice.h:366
void * memset(void *dest, int character, size_t len) __nonnull
A persistent I/O buffer.
Definition: iobuf.h:32
uint8_t flags
Flags.
Definition: ena.h:18