blob: c29d75d8f1b124ee7706da2e145189eaf7c5b65e [file] [log] [blame]
Uwe Zeisbergerf30c2262006-10-03 23:01:26 +02001/* linux/net/ipv4/arp.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 * Copyright (C) 1994 by Florian La Roche
4 *
5 * This module implements the Address Resolution Protocol ARP (RFC 826),
6 * which is used to convert IP addresses (or in the future maybe other
7 * high-level addresses) into a low-level hardware address (like an Ethernet
8 * address).
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * Fixes:
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090016 * Alan Cox : Removed the Ethernet assumptions in
Linus Torvalds1da177e2005-04-16 15:20:36 -070017 * Florian's code
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090018 * Alan Cox : Fixed some small errors in the ARP
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 * logic
20 * Alan Cox : Allow >4K in /proc
21 * Alan Cox : Make ARP add its own protocol entry
22 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
23 * Stephen Henson : Add AX25 support to arp_get_info()
24 * Alan Cox : Drop data when a device is downed.
25 * Alan Cox : Use init_timer().
26 * Alan Cox : Double lock fixes.
27 * Martin Seine : Move the arphdr structure
28 * to if_arp.h for compatibility.
29 * with BSD based programs.
30 * Andrew Tridgell : Added ARP netmask code and
31 * re-arranged proxy handling.
32 * Alan Cox : Changed to use notifiers.
33 * Niibe Yutaka : Reply for this device or proxies only.
34 * Alan Cox : Don't proxy across hardware types!
35 * Jonathan Naylor : Added support for NET/ROM.
36 * Mike Shaver : RFC1122 checks.
37 * Jonathan Naylor : Only lookup the hardware address for
38 * the correct hardware type.
39 * Germano Caronni : Assorted subtle races.
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090040 * Craig Schlenter : Don't modify permanent entry
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 * during arp_rcv.
42 * Russ Nelson : Tidied up a few bits.
43 * Alexey Kuznetsov: Major changes to caching and behaviour,
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090044 * eg intelligent arp probing and
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 * generation
46 * of host down events.
47 * Alan Cox : Missing unlock in device events.
48 * Eckes : ARP ioctl control errors.
49 * Alexey Kuznetsov: Arp free fix.
50 * Manuel Rodriguez: Gratuitous ARP.
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090051 * Jonathan Layes : Added arpd support through kerneld
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 * message queue (960314)
53 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
54 * Mike McLagan : Routing by source
55 * Stuart Cheshire : Metricom and grat arp fixes
56 * *** FOR 2.1 clean this up ***
57 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
58 * Alan Cox : Took the AP1000 nasty FDDI hack and
59 * folded into the mainstream FDDI code.
60 * Ack spit, Linus how did you allow that
61 * one in...
62 * Jes Sorensen : Make FDDI work again in 2.1.x and
63 * clean up the APFDDI & gen. FDDI bits.
64 * Alexey Kuznetsov: new arp state machine;
65 * now it is in net/core/neighbour.c.
66 * Krzysztof Halasa: Added Frame Relay ARP support.
67 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
68 * Shmulik Hen: Split arp_send to arp_create and
69 * arp_xmit so intermediate drivers like
70 * bonding can change the skb before
71 * sending (e.g. insert 8021q tag).
72 * Harald Welte : convert to make use of jenkins hash
73 */
74
75#include <linux/module.h>
76#include <linux/types.h>
77#include <linux/string.h>
78#include <linux/kernel.h>
Randy Dunlap4fc268d2006-01-11 12:17:47 -080079#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070080#include <linux/socket.h>
81#include <linux/sockios.h>
82#include <linux/errno.h>
83#include <linux/in.h>
84#include <linux/mm.h>
85#include <linux/inet.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020086#include <linux/inetdevice.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070087#include <linux/netdevice.h>
88#include <linux/etherdevice.h>
89#include <linux/fddidevice.h>
90#include <linux/if_arp.h>
91#include <linux/trdevice.h>
92#include <linux/skbuff.h>
93#include <linux/proc_fs.h>
94#include <linux/seq_file.h>
95#include <linux/stat.h>
96#include <linux/init.h>
97#include <linux/net.h>
98#include <linux/rcupdate.h>
99#include <linux/jhash.h>
100#ifdef CONFIG_SYSCTL
101#include <linux/sysctl.h>
102#endif
103
Eric W. Biederman457c4cb2007-09-12 12:01:34 +0200104#include <net/net_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105#include <net/ip.h>
106#include <net/icmp.h>
107#include <net/route.h>
108#include <net/protocol.h>
109#include <net/tcp.h>
110#include <net/sock.h>
111#include <net/arp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112#include <net/ax25.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113#include <net/netrom.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
115#include <net/atmclip.h>
116struct neigh_table *clip_tbl_hook;
117#endif
118
119#include <asm/system.h>
120#include <asm/uaccess.h>
121
122#include <linux/netfilter_arp.h>
123
124/*
125 * Interface to generic neighbour cache.
126 */
127static u32 arp_hash(const void *pkey, const struct net_device *dev);
128static int arp_constructor(struct neighbour *neigh);
129static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
130static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
131static void parp_redo(struct sk_buff *skb);
132
133static struct neigh_ops arp_generic_ops = {
134 .family = AF_INET,
135 .solicit = arp_solicit,
136 .error_report = arp_error_report,
137 .output = neigh_resolve_output,
138 .connected_output = neigh_connected_output,
139 .hh_output = dev_queue_xmit,
140 .queue_xmit = dev_queue_xmit,
141};
142
143static struct neigh_ops arp_hh_ops = {
144 .family = AF_INET,
145 .solicit = arp_solicit,
146 .error_report = arp_error_report,
147 .output = neigh_resolve_output,
148 .connected_output = neigh_resolve_output,
149 .hh_output = dev_queue_xmit,
150 .queue_xmit = dev_queue_xmit,
151};
152
153static struct neigh_ops arp_direct_ops = {
154 .family = AF_INET,
155 .output = dev_queue_xmit,
156 .connected_output = dev_queue_xmit,
157 .hh_output = dev_queue_xmit,
158 .queue_xmit = dev_queue_xmit,
159};
160
161struct neigh_ops arp_broken_ops = {
162 .family = AF_INET,
163 .solicit = arp_solicit,
164 .error_report = arp_error_report,
165 .output = neigh_compat_output,
166 .connected_output = neigh_compat_output,
167 .hh_output = dev_queue_xmit,
168 .queue_xmit = dev_queue_xmit,
169};
170
171struct neigh_table arp_tbl = {
172 .family = AF_INET,
173 .entry_size = sizeof(struct neighbour) + 4,
174 .key_len = 4,
175 .hash = arp_hash,
176 .constructor = arp_constructor,
177 .proxy_redo = parp_redo,
178 .id = "arp_cache",
179 .parms = {
180 .tbl = &arp_tbl,
181 .base_reachable_time = 30 * HZ,
182 .retrans_time = 1 * HZ,
183 .gc_staletime = 60 * HZ,
184 .reachable_time = 30 * HZ,
185 .delay_probe_time = 5 * HZ,
186 .queue_len = 3,
187 .ucast_probes = 3,
188 .mcast_probes = 3,
189 .anycast_delay = 1 * HZ,
190 .proxy_delay = (8 * HZ) / 10,
191 .proxy_qlen = 64,
192 .locktime = 1 * HZ,
193 },
194 .gc_interval = 30 * HZ,
195 .gc_thresh1 = 128,
196 .gc_thresh2 = 512,
197 .gc_thresh3 = 1024,
198};
199
Al Viro714e85b2006-11-14 20:51:49 -0800200int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201{
202 switch (dev->type) {
203 case ARPHRD_ETHER:
204 case ARPHRD_FDDI:
205 case ARPHRD_IEEE802:
206 ip_eth_mc_map(addr, haddr);
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900207 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 case ARPHRD_IEEE802_TR:
209 ip_tr_mc_map(addr, haddr);
210 return 0;
211 case ARPHRD_INFINIBAND:
Rolf Manderscheida9e527e2007-12-10 13:38:41 -0700212 ip_ib_mc_map(addr, dev->broadcast, haddr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 return 0;
214 default:
215 if (dir) {
216 memcpy(haddr, dev->broadcast, dev->addr_len);
217 return 0;
218 }
219 }
220 return -EINVAL;
221}
222
223
224static u32 arp_hash(const void *pkey, const struct net_device *dev)
225{
226 return jhash_2words(*(u32 *)pkey, dev->ifindex, arp_tbl.hash_rnd);
227}
228
229static int arp_constructor(struct neighbour *neigh)
230{
Al Virofd683222006-09-26 22:17:51 -0700231 __be32 addr = *(__be32*)neigh->primary_key;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 struct net_device *dev = neigh->dev;
233 struct in_device *in_dev;
234 struct neigh_parms *parms;
235
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 rcu_read_lock();
Herbert Xue5ed6392005-10-03 14:35:55 -0700237 in_dev = __in_dev_get_rcu(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 if (in_dev == NULL) {
239 rcu_read_unlock();
240 return -EINVAL;
241 }
242
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900243 neigh->type = inet_addr_type(dev_net(dev), addr);
Denis V. Luneva79878f2008-01-14 22:56:01 -0800244
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 parms = in_dev->arp_parms;
246 __neigh_parms_put(neigh->parms);
247 neigh->parms = neigh_parms_clone(parms);
248 rcu_read_unlock();
249
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700250 if (!dev->header_ops) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 neigh->nud_state = NUD_NOARP;
252 neigh->ops = &arp_direct_ops;
253 neigh->output = neigh->ops->queue_xmit;
254 } else {
255 /* Good devices (checked by reading texts, but only Ethernet is
256 tested)
257
258 ARPHRD_ETHER: (ethernet, apfddi)
259 ARPHRD_FDDI: (fddi)
260 ARPHRD_IEEE802: (tr)
261 ARPHRD_METRICOM: (strip)
262 ARPHRD_ARCNET:
263 etc. etc. etc.
264
265 ARPHRD_IPDDP will also work, if author repairs it.
266 I did not it, because this driver does not work even
267 in old paradigm.
268 */
269
270#if 1
271 /* So... these "amateur" devices are hopeless.
272 The only thing, that I can say now:
273 It is very sad that we need to keep ugly obsolete
274 code to make them happy.
275
276 They should be moved to more reasonable state, now
277 they use rebuild_header INSTEAD OF hard_start_xmit!!!
278 Besides that, they are sort of out of date
279 (a lot of redundant clones/copies, useless in 2.1),
280 I wonder why people believe that they work.
281 */
282 switch (dev->type) {
283 default:
284 break;
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900285 case ARPHRD_ROSE:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
287 case ARPHRD_AX25:
288#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
289 case ARPHRD_NETROM:
290#endif
291 neigh->ops = &arp_broken_ops;
292 neigh->output = neigh->ops->output;
293 return 0;
294#endif
295 ;}
296#endif
297 if (neigh->type == RTN_MULTICAST) {
298 neigh->nud_state = NUD_NOARP;
299 arp_mc_map(addr, neigh->ha, dev, 1);
300 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) {
301 neigh->nud_state = NUD_NOARP;
302 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
303 } else if (neigh->type == RTN_BROADCAST || dev->flags&IFF_POINTOPOINT) {
304 neigh->nud_state = NUD_NOARP;
305 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
306 }
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700307
308 if (dev->header_ops->cache)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 neigh->ops = &arp_hh_ops;
310 else
311 neigh->ops = &arp_generic_ops;
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700312
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 if (neigh->nud_state&NUD_VALID)
314 neigh->output = neigh->ops->connected_output;
315 else
316 neigh->output = neigh->ops->output;
317 }
318 return 0;
319}
320
321static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
322{
323 dst_link_failure(skb);
324 kfree_skb(skb);
325}
326
327static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
328{
Al Viroa61ced52006-09-26 21:27:54 -0700329 __be32 saddr = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 u8 *dst_ha = NULL;
331 struct net_device *dev = neigh->dev;
Al Viroa61ced52006-09-26 21:27:54 -0700332 __be32 target = *(__be32*)neigh->primary_key;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 int probes = atomic_read(&neigh->probes);
334 struct in_device *in_dev = in_dev_get(dev);
335
336 if (!in_dev)
337 return;
338
339 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
340 default:
341 case 0: /* By default announce any local IP */
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900342 if (skb && inet_addr_type(dev_net(dev), ip_hdr(skb)->saddr) == RTN_LOCAL)
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700343 saddr = ip_hdr(skb)->saddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 break;
345 case 1: /* Restrict announcements of saddr in same subnet */
346 if (!skb)
347 break;
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700348 saddr = ip_hdr(skb)->saddr;
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900349 if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 /* saddr should be known to target */
351 if (inet_addr_onlink(in_dev, target, saddr))
352 break;
353 }
354 saddr = 0;
355 break;
356 case 2: /* Avoid secondary IPs, get a primary/preferred one */
357 break;
358 }
359
360 if (in_dev)
361 in_dev_put(in_dev);
362 if (!saddr)
363 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
364
365 if ((probes -= neigh->parms->ucast_probes) < 0) {
366 if (!(neigh->nud_state&NUD_VALID))
367 printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n");
368 dst_ha = neigh->ha;
David S. Miller9ff56602008-02-17 18:39:54 -0800369 read_lock_bh(&neigh->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 } else if ((probes -= neigh->parms->app_probes) < 0) {
371#ifdef CONFIG_ARPD
372 neigh_app_ns(neigh);
373#endif
374 return;
375 }
376
377 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
378 dst_ha, dev->dev_addr, NULL);
David S. Miller9ff56602008-02-17 18:39:54 -0800379 if (dst_ha)
380 read_unlock_bh(&neigh->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381}
382
Denis V. Lunev9bd85e32008-01-14 23:05:55 -0800383static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384{
385 int scope;
386
387 switch (IN_DEV_ARP_IGNORE(in_dev)) {
388 case 0: /* Reply, the tip is already validated */
389 return 0;
390 case 1: /* Reply only if tip is configured on the incoming interface */
391 sip = 0;
392 scope = RT_SCOPE_HOST;
393 break;
394 case 2: /*
395 * Reply only if tip is configured on the incoming interface
396 * and is in same subnet as sip
397 */
398 scope = RT_SCOPE_HOST;
399 break;
400 case 3: /* Do not reply for scope host addresses */
401 sip = 0;
402 scope = RT_SCOPE_LINK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 break;
404 case 4: /* Reserved */
405 case 5:
406 case 6:
407 case 7:
408 return 0;
409 case 8: /* Do not reply */
410 return 1;
411 default:
412 return 0;
413 }
Denis V. Lunev9bd85e32008-01-14 23:05:55 -0800414 return !inet_confirm_addr(in_dev, sip, tip, scope);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415}
416
Al Viroed9bad02006-09-27 18:36:36 -0700417static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418{
419 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = sip,
420 .saddr = tip } } };
421 struct rtable *rt;
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900422 int flag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 /*unsigned long now; */
Pavel Emelyanovca12a1a2008-07-16 20:28:42 -0700424 struct net *net = dev_net(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425
Pavel Emelyanovca12a1a2008-07-16 20:28:42 -0700426 if (ip_route_output_key(net, &rt, &fl) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 return 1;
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900428 if (rt->u.dst.dev != dev) {
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700429 NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 flag = 1;
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900431 }
432 ip_rt_put(rt);
433 return flag;
434}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435
436/* OBSOLETE FUNCTIONS */
437
438/*
439 * Find an arp mapping in the cache. If not found, post a request.
440 *
441 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
442 * even if it exists. It is supposed that skb->dev was mangled
443 * by a virtual device (eql, shaper). Nobody but broken devices
444 * is allowed to use this function, it is scheduled to be removed. --ANK
445 */
446
Al Viroed9bad02006-09-27 18:36:36 -0700447static int arp_set_predefined(int addr_hint, unsigned char * haddr, __be32 paddr, struct net_device * dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448{
449 switch (addr_hint) {
450 case RTN_LOCAL:
451 printk(KERN_DEBUG "ARP: arp called for own IP address\n");
452 memcpy(haddr, dev->dev_addr, dev->addr_len);
453 return 1;
454 case RTN_MULTICAST:
455 arp_mc_map(paddr, haddr, dev, 1);
456 return 1;
457 case RTN_BROADCAST:
458 memcpy(haddr, dev->broadcast, dev->addr_len);
459 return 1;
460 }
461 return 0;
462}
463
464
465int arp_find(unsigned char *haddr, struct sk_buff *skb)
466{
467 struct net_device *dev = skb->dev;
Al Virofd683222006-09-26 22:17:51 -0700468 __be32 paddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 struct neighbour *n;
470
Eric Dumazetadf30902009-06-02 05:19:30 +0000471 if (!skb_dst(skb)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 printk(KERN_DEBUG "arp_find is called with dst==NULL\n");
473 kfree_skb(skb);
474 return 1;
475 }
476
Eric Dumazet511c3f92009-06-02 05:14:27 +0000477 paddr = skb_rtable(skb)->rt_gateway;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900479 if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr, paddr, dev))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 return 0;
481
482 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1);
483
484 if (n) {
485 n->used = jiffies;
486 if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) {
487 read_lock_bh(&n->lock);
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900488 memcpy(haddr, n->ha, dev->addr_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 read_unlock_bh(&n->lock);
490 neigh_release(n);
491 return 0;
492 }
493 neigh_release(n);
494 } else
495 kfree_skb(skb);
496 return 1;
497}
498
499/* END OF OBSOLETE FUNCTIONS */
500
501int arp_bind_neighbour(struct dst_entry *dst)
502{
503 struct net_device *dev = dst->dev;
504 struct neighbour *n = dst->neighbour;
505
506 if (dev == NULL)
507 return -EINVAL;
508 if (n == NULL) {
Jianjun Kongf4cca7f2008-11-03 02:48:14 -0800509 __be32 nexthop = ((struct rtable *)dst)->rt_gateway;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 if (dev->flags&(IFF_LOOPBACK|IFF_POINTOPOINT))
511 nexthop = 0;
512 n = __neigh_lookup_errno(
513#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
514 dev->type == ARPHRD_ATM ? clip_tbl_hook :
515#endif
516 &arp_tbl, &nexthop, dev);
517 if (IS_ERR(n))
518 return PTR_ERR(n);
519 dst->neighbour = n;
520 }
521 return 0;
522}
523
524/*
525 * Check if we can use proxy ARP for this path
526 */
527
528static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt)
529{
530 struct in_device *out_dev;
531 int imi, omi = -1;
532
533 if (!IN_DEV_PROXY_ARP(in_dev))
534 return 0;
535
536 if ((imi = IN_DEV_MEDIUM_ID(in_dev)) == 0)
537 return 1;
538 if (imi == -1)
539 return 0;
540
541 /* place to check for proxy_arp for routes */
542
543 if ((out_dev = in_dev_get(rt->u.dst.dev)) != NULL) {
544 omi = IN_DEV_MEDIUM_ID(out_dev);
545 in_dev_put(out_dev);
546 }
547 return (omi != imi && omi != -1);
548}
549
550/*
551 * Interface to link layer: send routine and receive handler.
552 */
553
554/*
555 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
556 * message.
557 */
Al Viroed9bad02006-09-27 18:36:36 -0700558struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
559 struct net_device *dev, __be32 src_ip,
Jan Engelhardtabfdf1c2008-01-31 03:59:24 -0800560 const unsigned char *dest_hw,
561 const unsigned char *src_hw,
562 const unsigned char *target_hw)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563{
564 struct sk_buff *skb;
565 struct arphdr *arp;
566 unsigned char *arp_ptr;
567
568 /*
569 * Allocate a buffer
570 */
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900571
Johannes Bergf5184d22008-05-12 20:48:31 -0700572 skb = alloc_skb(arp_hdr_len(dev) + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 if (skb == NULL)
574 return NULL;
575
576 skb_reserve(skb, LL_RESERVED_SPACE(dev));
Arnaldo Carvalho de Meloc1d2bbe2007-04-10 20:45:18 -0700577 skb_reset_network_header(skb);
Pavel Emelyanov988b7052008-03-03 12:20:57 -0800578 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 skb->dev = dev;
580 skb->protocol = htons(ETH_P_ARP);
581 if (src_hw == NULL)
582 src_hw = dev->dev_addr;
583 if (dest_hw == NULL)
584 dest_hw = dev->broadcast;
585
586 /*
587 * Fill the device header for the ARP frame
588 */
Stephen Hemminger0c4e8582007-10-09 01:36:32 -0700589 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 goto out;
591
592 /*
593 * Fill out the arp protocol part.
594 *
595 * The arp hardware type should match the device type, except for FDDI,
596 * which (according to RFC 1390) should always equal 1 (Ethernet).
597 */
598 /*
599 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
600 * DIX code for the protocol. Make these device structure fields.
601 */
602 switch (dev->type) {
603 default:
604 arp->ar_hrd = htons(dev->type);
605 arp->ar_pro = htons(ETH_P_IP);
606 break;
607
608#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
609 case ARPHRD_AX25:
610 arp->ar_hrd = htons(ARPHRD_AX25);
611 arp->ar_pro = htons(AX25_P_IP);
612 break;
613
614#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
615 case ARPHRD_NETROM:
616 arp->ar_hrd = htons(ARPHRD_NETROM);
617 arp->ar_pro = htons(AX25_P_IP);
618 break;
619#endif
620#endif
621
622#ifdef CONFIG_FDDI
623 case ARPHRD_FDDI:
624 arp->ar_hrd = htons(ARPHRD_ETHER);
625 arp->ar_pro = htons(ETH_P_IP);
626 break;
627#endif
628#ifdef CONFIG_TR
629 case ARPHRD_IEEE802_TR:
630 arp->ar_hrd = htons(ARPHRD_IEEE802);
631 arp->ar_pro = htons(ETH_P_IP);
632 break;
633#endif
634 }
635
636 arp->ar_hln = dev->addr_len;
637 arp->ar_pln = 4;
638 arp->ar_op = htons(type);
639
640 arp_ptr=(unsigned char *)(arp+1);
641
642 memcpy(arp_ptr, src_hw, dev->addr_len);
Jianjun Kongf4cca7f2008-11-03 02:48:14 -0800643 arp_ptr += dev->addr_len;
644 memcpy(arp_ptr, &src_ip, 4);
645 arp_ptr += 4;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 if (target_hw != NULL)
647 memcpy(arp_ptr, target_hw, dev->addr_len);
648 else
649 memset(arp_ptr, 0, dev->addr_len);
Jianjun Kongf4cca7f2008-11-03 02:48:14 -0800650 arp_ptr += dev->addr_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 memcpy(arp_ptr, &dest_ip, 4);
652
653 return skb;
654
655out:
656 kfree_skb(skb);
657 return NULL;
658}
659
660/*
661 * Send an arp packet.
662 */
663void arp_xmit(struct sk_buff *skb)
664{
665 /* Send it off, maybe filter it using firewalling first. */
Jan Engelhardtfdc93142008-10-20 03:34:51 -0700666 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667}
668
669/*
670 * Create and send an arp packet.
671 */
Al Viroed9bad02006-09-27 18:36:36 -0700672void arp_send(int type, int ptype, __be32 dest_ip,
673 struct net_device *dev, __be32 src_ip,
Jan Engelhardtabfdf1c2008-01-31 03:59:24 -0800674 const unsigned char *dest_hw, const unsigned char *src_hw,
675 const unsigned char *target_hw)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676{
677 struct sk_buff *skb;
678
679 /*
680 * No arp on this interface.
681 */
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900682
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 if (dev->flags&IFF_NOARP)
684 return;
685
686 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
687 dest_hw, src_hw, target_hw);
688 if (skb == NULL) {
689 return;
690 }
691
692 arp_xmit(skb);
693}
694
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695/*
696 * Process an arp request.
697 */
698
699static int arp_process(struct sk_buff *skb)
700{
701 struct net_device *dev = skb->dev;
702 struct in_device *in_dev = in_dev_get(dev);
703 struct arphdr *arp;
704 unsigned char *arp_ptr;
705 struct rtable *rt;
Mark Rydene0260fe2007-12-19 23:38:11 -0800706 unsigned char *sha;
Al Viro9e12bb22006-09-26 21:25:20 -0700707 __be32 sip, tip;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708 u16 dev_type = dev->type;
709 int addr_type;
710 struct neighbour *n;
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900711 struct net *net = dev_net(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712
713 /* arp_rcv below verifies the ARP header and verifies the device
714 * is ARP'able.
715 */
716
717 if (in_dev == NULL)
718 goto out;
719
Arnaldo Carvalho de Melod0a92be2007-03-12 20:56:31 -0300720 arp = arp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721
722 switch (dev_type) {
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900723 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 if (arp->ar_pro != htons(ETH_P_IP) ||
725 htons(dev_type) != arp->ar_hrd)
726 goto out;
727 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 case ARPHRD_ETHER:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 case ARPHRD_IEEE802_TR:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 case ARPHRD_FDDI:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 case ARPHRD_IEEE802:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 /*
733 * ETHERNET, Token Ring and Fibre Channel (which are IEEE 802
734 * devices, according to RFC 2625) devices will accept ARP
735 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
736 * This is the case also of FDDI, where the RFC 1390 says that
737 * FDDI devices should accept ARP hardware of (1) Ethernet,
738 * however, to be more robust, we'll accept both 1 (Ethernet)
739 * or 6 (IEEE 802.2)
740 */
741 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
742 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
743 arp->ar_pro != htons(ETH_P_IP))
744 goto out;
745 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 case ARPHRD_AX25:
747 if (arp->ar_pro != htons(AX25_P_IP) ||
748 arp->ar_hrd != htons(ARPHRD_AX25))
749 goto out;
750 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 case ARPHRD_NETROM:
752 if (arp->ar_pro != htons(AX25_P_IP) ||
753 arp->ar_hrd != htons(ARPHRD_NETROM))
754 goto out;
755 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756 }
757
758 /* Understand only these message types */
759
760 if (arp->ar_op != htons(ARPOP_REPLY) &&
761 arp->ar_op != htons(ARPOP_REQUEST))
762 goto out;
763
764/*
765 * Extract fields
766 */
767 arp_ptr= (unsigned char *)(arp+1);
768 sha = arp_ptr;
769 arp_ptr += dev->addr_len;
770 memcpy(&sip, arp_ptr, 4);
771 arp_ptr += 4;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 arp_ptr += dev->addr_len;
773 memcpy(&tip, arp_ptr, 4);
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900774/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 * Check for bad requests for 127.x.x.x and requests for multicast
776 * addresses. If this is one such, delete it.
777 */
Joe Perchesf97c1e02007-12-16 13:45:43 -0800778 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 goto out;
780
781/*
782 * Special case: We must set Frame Relay source Q.922 address
783 */
784 if (dev_type == ARPHRD_DLCI)
785 sha = dev->broadcast;
786
787/*
788 * Process entry. The idea here is we want to send a reply if it is a
789 * request for us or if it is a request for someone else that we hold
790 * a proxy for. We want to add an entry to our cache if it is a reply
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900791 * to us or if it is a request for our address.
792 * (The assumption for this last is that if someone is requesting our
793 * address, they are probably intending to talk to us, so it saves time
794 * if we cache their address. Their address is also probably not in
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 * our cache, since ours is not in their cache.)
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900796 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 * Putting this another way, we only care about replies if they are to
798 * us, in which case we add them to the cache. For requests, we care
799 * about those for us and those for our proxies. We reply to both,
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900800 * and in the case of requests for us we add the requester to the arp
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 * cache.
802 */
803
Eric W. Biedermanf8a68e72009-06-30 16:27:17 +0000804 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
805 if (sip == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 if (arp->ar_op == htons(ARPOP_REQUEST) &&
Denis V. Lunev49e8a272008-03-24 15:28:12 -0700807 inet_addr_type(net, tip) == RTN_LOCAL &&
Denis V. Lunev9bd85e32008-01-14 23:05:55 -0800808 !arp_ignore(in_dev, sip, tip))
Jonas Danielssonb4a98112007-11-20 17:38:16 -0800809 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
810 dev->dev_addr, sha);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 goto out;
812 }
813
814 if (arp->ar_op == htons(ARPOP_REQUEST) &&
815 ip_route_input(skb, tip, sip, 0, dev) == 0) {
816
Eric Dumazet511c3f92009-06-02 05:14:27 +0000817 rt = skb_rtable(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 addr_type = rt->rt_type;
819
820 if (addr_type == RTN_LOCAL) {
Ben Greear8164f1b2008-11-16 19:19:38 -0800821 int dont_send = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822
Ben Greear8164f1b2008-11-16 19:19:38 -0800823 if (!dont_send)
824 dont_send |= arp_ignore(in_dev,sip,tip);
825 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
826 dont_send |= arp_filter(sip,tip,dev);
827 if (!dont_send) {
828 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
829 if (n) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
Ben Greear8164f1b2008-11-16 19:19:38 -0800831 neigh_release(n);
832 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 }
834 goto out;
835 } else if (IN_DEV_FORWARD(in_dev)) {
Rami Rosencb7928a2008-01-09 00:18:24 -0800836 if (addr_type == RTN_UNICAST && rt->u.dst.dev != dev &&
Denis V. Lunev49e8a272008-03-24 15:28:12 -0700837 (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, net, &tip, dev, 0))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
839 if (n)
840 neigh_release(n);
841
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900842 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 skb->pkt_type == PACKET_HOST ||
844 in_dev->arp_parms->proxy_delay == 0) {
845 arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
846 } else {
847 pneigh_enqueue(&arp_tbl, in_dev->arp_parms, skb);
848 in_dev_put(in_dev);
849 return 0;
850 }
851 goto out;
852 }
853 }
854 }
855
856 /* Update our ARP tables */
857
858 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
859
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900860 if (IPV4_DEVCONF_ALL(dev_net(dev), ARP_ACCEPT)) {
Neil Hormanabd596a2006-03-20 22:39:47 -0800861 /* Unsolicited ARP is not accepted by default.
862 It is possible, that this option should be enabled for some
863 devices (strip is candidate)
864 */
865 if (n == NULL &&
866 arp->ar_op == htons(ARPOP_REPLY) &&
Denis V. Lunev49e8a272008-03-24 15:28:12 -0700867 inet_addr_type(net, sip) == RTN_UNICAST)
Jean Delvare1b1ac752007-07-14 20:51:44 -0700868 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
Neil Hormanabd596a2006-03-20 22:39:47 -0800869 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870
871 if (n) {
872 int state = NUD_REACHABLE;
873 int override;
874
875 /* If several different ARP replies follows back-to-back,
876 use the FIRST one. It is possible, if several proxy
877 agents are active. Taking the first reply prevents
878 arp trashing and chooses the fastest router.
879 */
880 override = time_after(jiffies, n->updated + n->parms->locktime);
881
882 /* Broadcast replies and request packets
883 do not assert neighbour reachability.
884 */
885 if (arp->ar_op != htons(ARPOP_REPLY) ||
886 skb->pkt_type != PACKET_HOST)
887 state = NUD_STALE;
888 neigh_update(n, sha, state, override ? NEIGH_UPDATE_F_OVERRIDE : 0);
889 neigh_release(n);
890 }
891
892out:
893 if (in_dev)
894 in_dev_put(in_dev);
Neil Hormanead2ceb2009-03-11 09:49:55 +0000895 consume_skb(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 return 0;
897}
898
Herbert Xu444fc8f2005-10-03 14:18:10 -0700899static void parp_redo(struct sk_buff *skb)
900{
901 arp_process(skb);
902}
903
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904
905/*
906 * Receive an arp request from the device layer.
907 */
908
Adrian Bunk6c97e722006-04-12 13:57:59 -0700909static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
910 struct packet_type *pt, struct net_device *orig_dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911{
912 struct arphdr *arp;
913
914 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
Pavel Emelyanov988b7052008-03-03 12:20:57 -0800915 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 goto freeskb;
917
Arnaldo Carvalho de Melod0a92be2007-03-12 20:56:31 -0300918 arp = arp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 if (arp->ar_hln != dev->addr_len ||
920 dev->flags & IFF_NOARP ||
921 skb->pkt_type == PACKET_OTHERHOST ||
922 skb->pkt_type == PACKET_LOOPBACK ||
923 arp->ar_pln != 4)
924 goto freeskb;
925
926 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
927 goto out_of_mem;
928
Patrick McHardya61bbcf2005-08-14 17:24:31 -0700929 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
930
Jan Engelhardtfdc93142008-10-20 03:34:51 -0700931 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932
933freeskb:
934 kfree_skb(skb);
935out_of_mem:
936 return 0;
937}
938
939/*
940 * User level interface (ioctl)
941 */
942
943/*
944 * Set (create) an ARP cache entry.
945 */
946
Pavel Emelyanov32e569b2007-12-16 13:30:39 -0800947static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
Pavel Emelyanovf8b33fd2007-12-05 21:20:50 -0800948{
949 if (dev == NULL) {
Pavel Emelyanov586f1212007-12-16 13:32:48 -0800950 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
Pavel Emelyanovf8b33fd2007-12-05 21:20:50 -0800951 return 0;
952 }
953 if (__in_dev_get_rtnl(dev)) {
954 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
955 return 0;
956 }
957 return -ENXIO;
958}
959
Pavel Emelyanov32e569b2007-12-16 13:30:39 -0800960static int arp_req_set_public(struct net *net, struct arpreq *r,
961 struct net_device *dev)
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800962{
963 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
964 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
965
966 if (mask && mask != htonl(0xFFFFFFFF))
967 return -EINVAL;
968 if (!dev && (r->arp_flags & ATF_COM)) {
Denis V. Lunev2db82b52008-01-14 22:58:55 -0800969 dev = dev_getbyhwaddr(net, r->arp_ha.sa_family,
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800970 r->arp_ha.sa_data);
971 if (!dev)
972 return -ENODEV;
973 }
974 if (mask) {
Denis V. Lunev2db82b52008-01-14 22:58:55 -0800975 if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL)
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800976 return -ENOBUFS;
977 return 0;
978 }
Pavel Emelyanovf8b33fd2007-12-05 21:20:50 -0800979
Pavel Emelyanov32e569b2007-12-16 13:30:39 -0800980 return arp_req_set_proxy(net, dev, 1);
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800981}
982
Pavel Emelyanov32e569b2007-12-16 13:30:39 -0800983static int arp_req_set(struct net *net, struct arpreq *r,
984 struct net_device * dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985{
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800986 __be32 ip;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 struct neighbour *neigh;
988 int err;
989
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800990 if (r->arp_flags & ATF_PUBL)
Pavel Emelyanov32e569b2007-12-16 13:30:39 -0800991 return arp_req_set_public(net, r, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992
Pavel Emelyanov43dc1702007-12-05 21:19:44 -0800993 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 if (r->arp_flags & ATF_PERM)
995 r->arp_flags |= ATF_COM;
996 if (dev == NULL) {
997 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip,
998 .tos = RTO_ONLINK } } };
999 struct rtable * rt;
Denis V. Lunevf2063512008-01-22 22:07:34 -08001000 if ((err = ip_route_output_key(net, &rt, &fl)) != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001 return err;
1002 dev = rt->u.dst.dev;
1003 ip_rt_put(rt);
1004 if (!dev)
1005 return -EINVAL;
1006 }
1007 switch (dev->type) {
1008#ifdef CONFIG_FDDI
1009 case ARPHRD_FDDI:
1010 /*
1011 * According to RFC 1390, FDDI devices should accept ARP
1012 * hardware types of 1 (Ethernet). However, to be more
1013 * robust, we'll accept hardware types of either 1 (Ethernet)
1014 * or 6 (IEEE 802.2).
1015 */
1016 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1017 r->arp_ha.sa_family != ARPHRD_ETHER &&
1018 r->arp_ha.sa_family != ARPHRD_IEEE802)
1019 return -EINVAL;
1020 break;
1021#endif
1022 default:
1023 if (r->arp_ha.sa_family != dev->type)
1024 return -EINVAL;
1025 break;
1026 }
1027
1028 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1029 err = PTR_ERR(neigh);
1030 if (!IS_ERR(neigh)) {
1031 unsigned state = NUD_STALE;
1032 if (r->arp_flags & ATF_PERM)
1033 state = NUD_PERMANENT;
1034 err = neigh_update(neigh, (r->arp_flags&ATF_COM) ?
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09001035 r->arp_ha.sa_data : NULL, state,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 NEIGH_UPDATE_F_OVERRIDE|
1037 NEIGH_UPDATE_F_ADMIN);
1038 neigh_release(neigh);
1039 }
1040 return err;
1041}
1042
1043static unsigned arp_state_to_flags(struct neighbour *neigh)
1044{
1045 unsigned flags = 0;
1046 if (neigh->nud_state&NUD_PERMANENT)
1047 flags = ATF_PERM|ATF_COM;
1048 else if (neigh->nud_state&NUD_VALID)
1049 flags = ATF_COM;
1050 return flags;
1051}
1052
1053/*
1054 * Get an ARP cache entry.
1055 */
1056
1057static int arp_req_get(struct arpreq *r, struct net_device *dev)
1058{
Al Viroed9bad02006-09-27 18:36:36 -07001059 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001060 struct neighbour *neigh;
1061 int err = -ENXIO;
1062
1063 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1064 if (neigh) {
1065 read_lock_bh(&neigh->lock);
1066 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1067 r->arp_flags = arp_state_to_flags(neigh);
1068 read_unlock_bh(&neigh->lock);
1069 r->arp_ha.sa_family = dev->type;
1070 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1071 neigh_release(neigh);
1072 err = 0;
1073 }
1074 return err;
1075}
1076
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001077static int arp_req_delete_public(struct net *net, struct arpreq *r,
1078 struct net_device *dev)
Pavel Emelyanov46479b42007-12-05 21:20:18 -08001079{
1080 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1081 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1082
1083 if (mask == htonl(0xFFFFFFFF))
Denis V. Lunev2db82b52008-01-14 22:58:55 -08001084 return pneigh_delete(&arp_tbl, net, &ip, dev);
Pavel Emelyanov46479b42007-12-05 21:20:18 -08001085
Pavel Emelyanovf8b33fd2007-12-05 21:20:50 -08001086 if (mask)
1087 return -EINVAL;
1088
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001089 return arp_req_set_proxy(net, dev, 0);
Pavel Emelyanov46479b42007-12-05 21:20:18 -08001090}
1091
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001092static int arp_req_delete(struct net *net, struct arpreq *r,
1093 struct net_device * dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094{
1095 int err;
Pavel Emelyanov46479b42007-12-05 21:20:18 -08001096 __be32 ip;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097 struct neighbour *neigh;
1098
Pavel Emelyanov46479b42007-12-05 21:20:18 -08001099 if (r->arp_flags & ATF_PUBL)
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001100 return arp_req_delete_public(net, r, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101
Pavel Emelyanov46479b42007-12-05 21:20:18 -08001102 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103 if (dev == NULL) {
1104 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip,
1105 .tos = RTO_ONLINK } } };
1106 struct rtable * rt;
Denis V. Lunevf2063512008-01-22 22:07:34 -08001107 if ((err = ip_route_output_key(net, &rt, &fl)) != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 return err;
1109 dev = rt->u.dst.dev;
1110 ip_rt_put(rt);
1111 if (!dev)
1112 return -EINVAL;
1113 }
1114 err = -ENXIO;
1115 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1116 if (neigh) {
1117 if (neigh->nud_state&~NUD_NOARP)
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09001118 err = neigh_update(neigh, NULL, NUD_FAILED,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119 NEIGH_UPDATE_F_OVERRIDE|
1120 NEIGH_UPDATE_F_ADMIN);
1121 neigh_release(neigh);
1122 }
1123 return err;
1124}
1125
1126/*
1127 * Handle an ARP layer I/O control request.
1128 */
1129
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001130int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131{
1132 int err;
1133 struct arpreq r;
1134 struct net_device *dev = NULL;
1135
1136 switch (cmd) {
1137 case SIOCDARP:
1138 case SIOCSARP:
1139 if (!capable(CAP_NET_ADMIN))
1140 return -EPERM;
1141 case SIOCGARP:
1142 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1143 if (err)
1144 return -EFAULT;
1145 break;
1146 default:
1147 return -EINVAL;
1148 }
1149
1150 if (r.arp_pa.sa_family != AF_INET)
1151 return -EPFNOSUPPORT;
1152
1153 if (!(r.arp_flags & ATF_PUBL) &&
1154 (r.arp_flags & (ATF_NETMASK|ATF_DONTPUB)))
1155 return -EINVAL;
1156 if (!(r.arp_flags & ATF_NETMASK))
1157 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1158 htonl(0xFFFFFFFFUL);
1159 rtnl_lock();
1160 if (r.arp_dev[0]) {
1161 err = -ENODEV;
Denis V. Lunev2db82b52008-01-14 22:58:55 -08001162 if ((dev = __dev_get_by_name(net, r.arp_dev)) == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163 goto out;
1164
1165 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1166 if (!r.arp_ha.sa_family)
1167 r.arp_ha.sa_family = dev->type;
1168 err = -EINVAL;
1169 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1170 goto out;
1171 } else if (cmd == SIOCGARP) {
1172 err = -ENODEV;
1173 goto out;
1174 }
1175
Stephen Hemminger132adf52007-03-08 20:44:43 -08001176 switch (cmd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 case SIOCDARP:
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001178 err = arp_req_delete(net, &r, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001179 break;
1180 case SIOCSARP:
Pavel Emelyanov32e569b2007-12-16 13:30:39 -08001181 err = arp_req_set(net, &r, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 break;
1183 case SIOCGARP:
1184 err = arp_req_get(&r, dev);
1185 if (!err && copy_to_user(arg, &r, sizeof(r)))
1186 err = -EFAULT;
1187 break;
1188 }
1189out:
1190 rtnl_unlock();
1191 return err;
1192}
1193
1194static int arp_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1195{
1196 struct net_device *dev = ptr;
1197
1198 switch (event) {
1199 case NETDEV_CHANGEADDR:
1200 neigh_changeaddr(&arp_tbl, dev);
Denis V. Lunev76e6ebf2008-07-05 19:00:44 -07001201 rt_cache_flush(dev_net(dev), 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202 break;
1203 default:
1204 break;
1205 }
1206
1207 return NOTIFY_DONE;
1208}
1209
1210static struct notifier_block arp_netdev_notifier = {
1211 .notifier_call = arp_netdev_event,
1212};
1213
1214/* Note, that it is not on notifier chain.
1215 It is necessary, that this routine was called after route cache will be
1216 flushed.
1217 */
1218void arp_ifdown(struct net_device *dev)
1219{
1220 neigh_ifdown(&arp_tbl, dev);
1221}
1222
1223
1224/*
1225 * Called once on startup.
1226 */
1227
Stephen Hemminger7546dd92009-03-09 08:18:29 +00001228static struct packet_type arp_packet_type __read_mostly = {
Harvey Harrison09640e62009-02-01 00:45:17 -08001229 .type = cpu_to_be16(ETH_P_ARP),
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230 .func = arp_rcv,
1231};
1232
1233static int arp_proc_init(void);
1234
1235void __init arp_init(void)
1236{
1237 neigh_table_init(&arp_tbl);
1238
1239 dev_add_pack(&arp_packet_type);
1240 arp_proc_init();
1241#ifdef CONFIG_SYSCTL
1242 neigh_sysctl_register(NULL, &arp_tbl.parms, NET_IPV4,
1243 NET_IPV4_NEIGH, "ipv4", NULL, NULL);
1244#endif
1245 register_netdevice_notifier(&arp_netdev_notifier);
1246}
1247
1248#ifdef CONFIG_PROC_FS
1249#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1250
1251/* ------------------------------------------------------------------------ */
1252/*
1253 * ax25 -> ASCII conversion
1254 */
1255static char *ax2asc2(ax25_address *a, char *buf)
1256{
1257 char c, *s;
1258 int n;
1259
1260 for (n = 0, s = buf; n < 6; n++) {
1261 c = (a->ax25_call[n] >> 1) & 0x7F;
1262
1263 if (c != ' ') *s++ = c;
1264 }
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09001265
Linus Torvalds1da177e2005-04-16 15:20:36 -07001266 *s++ = '-';
1267
1268 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) {
1269 *s++ = '1';
1270 n -= 10;
1271 }
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09001272
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273 *s++ = n + '0';
1274 *s++ = '\0';
1275
1276 if (*buf == '\0' || *buf == '-')
1277 return "*";
1278
1279 return buf;
1280
1281}
1282#endif /* CONFIG_AX25 */
1283
1284#define HBUFFERLEN 30
1285
1286static void arp_format_neigh_entry(struct seq_file *seq,
1287 struct neighbour *n)
1288{
1289 char hbuffer[HBUFFERLEN];
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290 int k, j;
1291 char tbuf[16];
1292 struct net_device *dev = n->dev;
1293 int hatype = dev->type;
1294
1295 read_lock(&n->lock);
1296 /* Convert hardware address to XX:XX:XX:XX ... form. */
1297#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1298 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1299 ax2asc2((ax25_address *)n->ha, hbuffer);
1300 else {
1301#endif
1302 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
Denis Cheng51f82a22008-05-21 17:34:32 -07001303 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1304 hbuffer[k++] = hex_asc_lo(n->ha[j]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305 hbuffer[k++] = ':';
1306 }
1307 hbuffer[--k] = 0;
1308#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
1309 }
1310#endif
Harvey Harrison673d57e2008-10-31 00:53:57 -07001311 sprintf(tbuf, "%pI4", n->primary_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1313 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1314 read_unlock(&n->lock);
1315}
1316
1317static void arp_format_pneigh_entry(struct seq_file *seq,
1318 struct pneigh_entry *n)
1319{
1320 struct net_device *dev = n->dev;
1321 int hatype = dev ? dev->type : 0;
1322 char tbuf[16];
1323
Harvey Harrison673d57e2008-10-31 00:53:57 -07001324 sprintf(tbuf, "%pI4", n->key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1326 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1327 dev ? dev->name : "*");
1328}
1329
1330static int arp_seq_show(struct seq_file *seq, void *v)
1331{
1332 if (v == SEQ_START_TOKEN) {
1333 seq_puts(seq, "IP address HW type Flags "
1334 "HW address Mask Device\n");
1335 } else {
1336 struct neigh_seq_state *state = seq->private;
1337
1338 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1339 arp_format_pneigh_entry(seq, v);
1340 else
1341 arp_format_neigh_entry(seq, v);
1342 }
1343
1344 return 0;
1345}
1346
1347static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1348{
1349 /* Don't want to confuse "arp -a" w/ magic entries,
1350 * so we tell the generic iterator to skip NUD_NOARP.
1351 */
1352 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1353}
1354
1355/* ------------------------------------------------------------------------ */
1356
Stephen Hemmingerf6908082007-03-12 14:34:29 -07001357static const struct seq_operations arp_seq_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001358 .start = arp_seq_start,
1359 .next = neigh_seq_next,
1360 .stop = neigh_seq_stop,
1361 .show = arp_seq_show,
1362};
1363
1364static int arp_seq_open(struct inode *inode, struct file *file)
1365{
Eric W. Biederman426b5302008-01-24 00:13:18 -08001366 return seq_open_net(inode, file, &arp_seq_ops,
1367 sizeof(struct neigh_seq_state));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368}
1369
Arjan van de Ven9a321442007-02-12 00:55:35 -08001370static const struct file_operations arp_seq_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001371 .owner = THIS_MODULE,
1372 .open = arp_seq_open,
1373 .read = seq_read,
1374 .llseek = seq_lseek,
Eric W. Biederman426b5302008-01-24 00:13:18 -08001375 .release = seq_release_net,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001376};
1377
Denis V. Lunevffc31d32008-03-24 15:28:43 -07001378
1379static int __net_init arp_net_init(struct net *net)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001380{
Denis V. Lunevffc31d32008-03-24 15:28:43 -07001381 if (!proc_net_fops_create(net, "arp", S_IRUGO, &arp_seq_fops))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382 return -ENOMEM;
1383 return 0;
1384}
1385
Denis V. Lunevffc31d32008-03-24 15:28:43 -07001386static void __net_exit arp_net_exit(struct net *net)
1387{
1388 proc_net_remove(net, "arp");
1389}
1390
1391static struct pernet_operations arp_net_ops = {
1392 .init = arp_net_init,
1393 .exit = arp_net_exit,
1394};
1395
1396static int __init arp_proc_init(void)
1397{
1398 return register_pernet_subsys(&arp_net_ops);
1399}
1400
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401#else /* CONFIG_PROC_FS */
1402
1403static int __init arp_proc_init(void)
1404{
1405 return 0;
1406}
1407
1408#endif /* CONFIG_PROC_FS */
1409
1410EXPORT_SYMBOL(arp_broken_ops);
1411EXPORT_SYMBOL(arp_find);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412EXPORT_SYMBOL(arp_create);
1413EXPORT_SYMBOL(arp_xmit);
1414EXPORT_SYMBOL(arp_send);
1415EXPORT_SYMBOL(arp_tbl);
1416
1417#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
1418EXPORT_SYMBOL(clip_tbl_hook);
1419#endif