Commit | Line | Data |
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f30c2269 | 1 | /* linux/net/ipv4/arp.c |
1da177e4 LT |
2 | * |
3 | * 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: | |
e905a9ed | 16 | * Alan Cox : Removed the Ethernet assumptions in |
1da177e4 | 17 | * Florian's code |
e905a9ed | 18 | * Alan Cox : Fixed some small errors in the ARP |
1da177e4 LT |
19 | * 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. | |
e905a9ed | 40 | * Craig Schlenter : Don't modify permanent entry |
1da177e4 LT |
41 | * during arp_rcv. |
42 | * Russ Nelson : Tidied up a few bits. | |
43 | * Alexey Kuznetsov: Major changes to caching and behaviour, | |
e905a9ed | 44 | * eg intelligent arp probing and |
1da177e4 LT |
45 | * 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. | |
e905a9ed | 51 | * Jonathan Layes : Added arpd support through kerneld |
1da177e4 LT |
52 | * 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. | |
deffd777 | 58 | * Alan Cox : Took the AP1000 nasty FDDI hack and |
1da177e4 LT |
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 | |
65324144 | 73 | * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support. |
1da177e4 LT |
74 | */ |
75 | ||
91df42be JP |
76 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
77 | ||
1da177e4 LT |
78 | #include <linux/module.h> |
79 | #include <linux/types.h> | |
80 | #include <linux/string.h> | |
81 | #include <linux/kernel.h> | |
4fc268d2 | 82 | #include <linux/capability.h> |
1da177e4 LT |
83 | #include <linux/socket.h> |
84 | #include <linux/sockios.h> | |
85 | #include <linux/errno.h> | |
86 | #include <linux/in.h> | |
87 | #include <linux/mm.h> | |
88 | #include <linux/inet.h> | |
14c85021 | 89 | #include <linux/inetdevice.h> |
1da177e4 LT |
90 | #include <linux/netdevice.h> |
91 | #include <linux/etherdevice.h> | |
92 | #include <linux/fddidevice.h> | |
93 | #include <linux/if_arp.h> | |
1da177e4 LT |
94 | #include <linux/skbuff.h> |
95 | #include <linux/proc_fs.h> | |
96 | #include <linux/seq_file.h> | |
97 | #include <linux/stat.h> | |
98 | #include <linux/init.h> | |
99 | #include <linux/net.h> | |
100 | #include <linux/rcupdate.h> | |
5a0e3ad6 | 101 | #include <linux/slab.h> |
1da177e4 LT |
102 | #ifdef CONFIG_SYSCTL |
103 | #include <linux/sysctl.h> | |
104 | #endif | |
105 | ||
457c4cbc | 106 | #include <net/net_namespace.h> |
1da177e4 LT |
107 | #include <net/ip.h> |
108 | #include <net/icmp.h> | |
109 | #include <net/route.h> | |
110 | #include <net/protocol.h> | |
111 | #include <net/tcp.h> | |
112 | #include <net/sock.h> | |
113 | #include <net/arp.h> | |
1da177e4 | 114 | #include <net/ax25.h> |
1da177e4 | 115 | #include <net/netrom.h> |
1da177e4 | 116 | |
deffd777 | 117 | #include <linux/uaccess.h> |
1da177e4 LT |
118 | |
119 | #include <linux/netfilter_arp.h> | |
120 | ||
121 | /* | |
122 | * Interface to generic neighbour cache. | |
123 | */ | |
2c2aba6c | 124 | static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd); |
1da177e4 LT |
125 | static int arp_constructor(struct neighbour *neigh); |
126 | static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); | |
127 | static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); | |
128 | static void parp_redo(struct sk_buff *skb); | |
129 | ||
89d69d2b | 130 | static const struct neigh_ops arp_generic_ops = { |
1da177e4 LT |
131 | .family = AF_INET, |
132 | .solicit = arp_solicit, | |
133 | .error_report = arp_error_report, | |
134 | .output = neigh_resolve_output, | |
135 | .connected_output = neigh_connected_output, | |
1da177e4 LT |
136 | }; |
137 | ||
89d69d2b | 138 | static const struct neigh_ops arp_hh_ops = { |
1da177e4 LT |
139 | .family = AF_INET, |
140 | .solicit = arp_solicit, | |
141 | .error_report = arp_error_report, | |
142 | .output = neigh_resolve_output, | |
143 | .connected_output = neigh_resolve_output, | |
1da177e4 LT |
144 | }; |
145 | ||
89d69d2b | 146 | static const struct neigh_ops arp_direct_ops = { |
1da177e4 | 147 | .family = AF_INET, |
8f40b161 DM |
148 | .output = neigh_direct_output, |
149 | .connected_output = neigh_direct_output, | |
1da177e4 LT |
150 | }; |
151 | ||
a64de47c | 152 | static const struct neigh_ops arp_broken_ops = { |
1da177e4 LT |
153 | .family = AF_INET, |
154 | .solicit = arp_solicit, | |
155 | .error_report = arp_error_report, | |
156 | .output = neigh_compat_output, | |
157 | .connected_output = neigh_compat_output, | |
1da177e4 LT |
158 | }; |
159 | ||
160 | struct neigh_table arp_tbl = { | |
deffd777 | 161 | .family = AF_INET, |
deffd777 CG |
162 | .key_len = 4, |
163 | .hash = arp_hash, | |
164 | .constructor = arp_constructor, | |
165 | .proxy_redo = parp_redo, | |
166 | .id = "arp_cache", | |
167 | .parms = { | |
168 | .tbl = &arp_tbl, | |
169 | .base_reachable_time = 30 * HZ, | |
170 | .retrans_time = 1 * HZ, | |
171 | .gc_staletime = 60 * HZ, | |
172 | .reachable_time = 30 * HZ, | |
173 | .delay_probe_time = 5 * HZ, | |
8b5c171b | 174 | .queue_len_bytes = 64*1024, |
deffd777 CG |
175 | .ucast_probes = 3, |
176 | .mcast_probes = 3, | |
177 | .anycast_delay = 1 * HZ, | |
178 | .proxy_delay = (8 * HZ) / 10, | |
179 | .proxy_qlen = 64, | |
180 | .locktime = 1 * HZ, | |
1da177e4 | 181 | }, |
deffd777 CG |
182 | .gc_interval = 30 * HZ, |
183 | .gc_thresh1 = 128, | |
184 | .gc_thresh2 = 512, | |
185 | .gc_thresh3 = 1024, | |
1da177e4 | 186 | }; |
4bc2f18b | 187 | EXPORT_SYMBOL(arp_tbl); |
1da177e4 | 188 | |
714e85be | 189 | int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir) |
1da177e4 LT |
190 | { |
191 | switch (dev->type) { | |
192 | case ARPHRD_ETHER: | |
193 | case ARPHRD_FDDI: | |
194 | case ARPHRD_IEEE802: | |
195 | ip_eth_mc_map(addr, haddr); | |
e905a9ed | 196 | return 0; |
1da177e4 | 197 | case ARPHRD_INFINIBAND: |
a9e527e3 | 198 | ip_ib_mc_map(addr, dev->broadcast, haddr); |
1da177e4 | 199 | return 0; |
93ca3bb5 TT |
200 | case ARPHRD_IPGRE: |
201 | ip_ipgre_mc_map(addr, dev->broadcast, haddr); | |
202 | return 0; | |
1da177e4 LT |
203 | default: |
204 | if (dir) { | |
205 | memcpy(haddr, dev->broadcast, dev->addr_len); | |
206 | return 0; | |
207 | } | |
208 | } | |
209 | return -EINVAL; | |
210 | } | |
211 | ||
212 | ||
d6bf7817 ED |
213 | static u32 arp_hash(const void *pkey, |
214 | const struct net_device *dev, | |
2c2aba6c | 215 | __u32 *hash_rnd) |
1da177e4 | 216 | { |
2c2aba6c | 217 | return arp_hashfn(*(u32 *)pkey, dev, *hash_rnd); |
1da177e4 LT |
218 | } |
219 | ||
220 | static int arp_constructor(struct neighbour *neigh) | |
221 | { | |
deffd777 | 222 | __be32 addr = *(__be32 *)neigh->primary_key; |
1da177e4 LT |
223 | struct net_device *dev = neigh->dev; |
224 | struct in_device *in_dev; | |
225 | struct neigh_parms *parms; | |
226 | ||
1da177e4 | 227 | rcu_read_lock(); |
e5ed6399 | 228 | in_dev = __in_dev_get_rcu(dev); |
1da177e4 LT |
229 | if (in_dev == NULL) { |
230 | rcu_read_unlock(); | |
231 | return -EINVAL; | |
232 | } | |
233 | ||
c346dca1 | 234 | neigh->type = inet_addr_type(dev_net(dev), addr); |
a79878f0 | 235 | |
1da177e4 LT |
236 | parms = in_dev->arp_parms; |
237 | __neigh_parms_put(neigh->parms); | |
238 | neigh->parms = neigh_parms_clone(parms); | |
239 | rcu_read_unlock(); | |
240 | ||
3b04ddde | 241 | if (!dev->header_ops) { |
1da177e4 LT |
242 | neigh->nud_state = NUD_NOARP; |
243 | neigh->ops = &arp_direct_ops; | |
8f40b161 | 244 | neigh->output = neigh_direct_output; |
1da177e4 LT |
245 | } else { |
246 | /* Good devices (checked by reading texts, but only Ethernet is | |
247 | tested) | |
248 | ||
249 | ARPHRD_ETHER: (ethernet, apfddi) | |
250 | ARPHRD_FDDI: (fddi) | |
251 | ARPHRD_IEEE802: (tr) | |
252 | ARPHRD_METRICOM: (strip) | |
253 | ARPHRD_ARCNET: | |
254 | etc. etc. etc. | |
255 | ||
256 | ARPHRD_IPDDP will also work, if author repairs it. | |
257 | I did not it, because this driver does not work even | |
258 | in old paradigm. | |
259 | */ | |
260 | ||
261 | #if 1 | |
262 | /* So... these "amateur" devices are hopeless. | |
263 | The only thing, that I can say now: | |
264 | It is very sad that we need to keep ugly obsolete | |
265 | code to make them happy. | |
266 | ||
267 | They should be moved to more reasonable state, now | |
268 | they use rebuild_header INSTEAD OF hard_start_xmit!!! | |
269 | Besides that, they are sort of out of date | |
270 | (a lot of redundant clones/copies, useless in 2.1), | |
271 | I wonder why people believe that they work. | |
272 | */ | |
273 | switch (dev->type) { | |
274 | default: | |
275 | break; | |
e905a9ed | 276 | case ARPHRD_ROSE: |
40e4783e | 277 | #if IS_ENABLED(CONFIG_AX25) |
1da177e4 | 278 | case ARPHRD_AX25: |
40e4783e | 279 | #if IS_ENABLED(CONFIG_NETROM) |
1da177e4 LT |
280 | case ARPHRD_NETROM: |
281 | #endif | |
282 | neigh->ops = &arp_broken_ops; | |
283 | neigh->output = neigh->ops->output; | |
284 | return 0; | |
deffd777 CG |
285 | #else |
286 | break; | |
1da177e4 | 287 | #endif |
deffd777 | 288 | } |
1da177e4 LT |
289 | #endif |
290 | if (neigh->type == RTN_MULTICAST) { | |
291 | neigh->nud_state = NUD_NOARP; | |
292 | arp_mc_map(addr, neigh->ha, dev, 1); | |
deffd777 | 293 | } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) { |
1da177e4 LT |
294 | neigh->nud_state = NUD_NOARP; |
295 | memcpy(neigh->ha, dev->dev_addr, dev->addr_len); | |
deffd777 CG |
296 | } else if (neigh->type == RTN_BROADCAST || |
297 | (dev->flags & IFF_POINTOPOINT)) { | |
1da177e4 LT |
298 | neigh->nud_state = NUD_NOARP; |
299 | memcpy(neigh->ha, dev->broadcast, dev->addr_len); | |
300 | } | |
3b04ddde SH |
301 | |
302 | if (dev->header_ops->cache) | |
1da177e4 LT |
303 | neigh->ops = &arp_hh_ops; |
304 | else | |
305 | neigh->ops = &arp_generic_ops; | |
3b04ddde | 306 | |
deffd777 | 307 | if (neigh->nud_state & NUD_VALID) |
1da177e4 LT |
308 | neigh->output = neigh->ops->connected_output; |
309 | else | |
310 | neigh->output = neigh->ops->output; | |
311 | } | |
312 | return 0; | |
313 | } | |
314 | ||
315 | static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) | |
316 | { | |
317 | dst_link_failure(skb); | |
318 | kfree_skb(skb); | |
319 | } | |
320 | ||
321 | static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) | |
322 | { | |
a61ced5d | 323 | __be32 saddr = 0; |
1da177e4 LT |
324 | u8 *dst_ha = NULL; |
325 | struct net_device *dev = neigh->dev; | |
deffd777 | 326 | __be32 target = *(__be32 *)neigh->primary_key; |
1da177e4 | 327 | int probes = atomic_read(&neigh->probes); |
4b4194c4 | 328 | struct in_device *in_dev; |
1da177e4 | 329 | |
4b4194c4 ED |
330 | rcu_read_lock(); |
331 | in_dev = __in_dev_get_rcu(dev); | |
332 | if (!in_dev) { | |
333 | rcu_read_unlock(); | |
1da177e4 | 334 | return; |
4b4194c4 | 335 | } |
1da177e4 LT |
336 | switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { |
337 | default: | |
338 | case 0: /* By default announce any local IP */ | |
deffd777 CG |
339 | if (skb && inet_addr_type(dev_net(dev), |
340 | ip_hdr(skb)->saddr) == RTN_LOCAL) | |
eddc9ec5 | 341 | saddr = ip_hdr(skb)->saddr; |
1da177e4 LT |
342 | break; |
343 | case 1: /* Restrict announcements of saddr in same subnet */ | |
344 | if (!skb) | |
345 | break; | |
eddc9ec5 | 346 | saddr = ip_hdr(skb)->saddr; |
c346dca1 | 347 | if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) { |
1da177e4 LT |
348 | /* saddr should be known to target */ |
349 | if (inet_addr_onlink(in_dev, target, saddr)) | |
350 | break; | |
351 | } | |
352 | saddr = 0; | |
353 | break; | |
354 | case 2: /* Avoid secondary IPs, get a primary/preferred one */ | |
355 | break; | |
356 | } | |
4b4194c4 | 357 | rcu_read_unlock(); |
1da177e4 | 358 | |
1da177e4 LT |
359 | if (!saddr) |
360 | saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); | |
361 | ||
deffd777 CG |
362 | probes -= neigh->parms->ucast_probes; |
363 | if (probes < 0) { | |
364 | if (!(neigh->nud_state & NUD_VALID)) | |
91df42be | 365 | pr_debug("trying to ucast probe in NUD_INVALID\n"); |
1da177e4 | 366 | dst_ha = neigh->ha; |
9ff56607 | 367 | read_lock_bh(&neigh->lock); |
deffd777 CG |
368 | } else { |
369 | probes -= neigh->parms->app_probes; | |
370 | if (probes < 0) { | |
1da177e4 | 371 | #ifdef CONFIG_ARPD |
deffd777 | 372 | neigh_app_ns(neigh); |
1da177e4 | 373 | #endif |
deffd777 CG |
374 | return; |
375 | } | |
1da177e4 LT |
376 | } |
377 | ||
378 | arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, | |
379 | dst_ha, dev->dev_addr, NULL); | |
9ff56607 DM |
380 | if (dst_ha) |
381 | read_unlock_bh(&neigh->lock); | |
1da177e4 LT |
382 | } |
383 | ||
9bd85e32 | 384 | static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip) |
1da177e4 LT |
385 | { |
386 | int scope; | |
387 | ||
388 | switch (IN_DEV_ARP_IGNORE(in_dev)) { | |
389 | case 0: /* Reply, the tip is already validated */ | |
390 | return 0; | |
391 | case 1: /* Reply only if tip is configured on the incoming interface */ | |
392 | sip = 0; | |
393 | scope = RT_SCOPE_HOST; | |
394 | break; | |
395 | case 2: /* | |
396 | * Reply only if tip is configured on the incoming interface | |
397 | * and is in same subnet as sip | |
398 | */ | |
399 | scope = RT_SCOPE_HOST; | |
400 | break; | |
401 | case 3: /* Do not reply for scope host addresses */ | |
402 | sip = 0; | |
403 | scope = RT_SCOPE_LINK; | |
1da177e4 LT |
404 | break; |
405 | case 4: /* Reserved */ | |
406 | case 5: | |
407 | case 6: | |
408 | case 7: | |
409 | return 0; | |
410 | case 8: /* Do not reply */ | |
411 | return 1; | |
412 | default: | |
413 | return 0; | |
414 | } | |
9bd85e32 | 415 | return !inet_confirm_addr(in_dev, sip, tip, scope); |
1da177e4 LT |
416 | } |
417 | ||
ed9bad06 | 418 | static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) |
1da177e4 | 419 | { |
1da177e4 | 420 | struct rtable *rt; |
e905a9ed | 421 | int flag = 0; |
1da177e4 | 422 | /*unsigned long now; */ |
ca12a1a4 | 423 | struct net *net = dev_net(dev); |
1da177e4 | 424 | |
78fbfd8a | 425 | rt = ip_route_output(net, sip, tip, 0, 0); |
b23dd4fe | 426 | if (IS_ERR(rt)) |
1da177e4 | 427 | return 1; |
d8d1f30b | 428 | if (rt->dst.dev != dev) { |
de0744af | 429 | NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER); |
1da177e4 | 430 | flag = 1; |
e905a9ed YH |
431 | } |
432 | ip_rt_put(rt); | |
433 | return flag; | |
434 | } | |
1da177e4 LT |
435 | |
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 | ||
deffd777 CG |
447 | static int arp_set_predefined(int addr_hint, unsigned char *haddr, |
448 | __be32 paddr, struct net_device *dev) | |
1da177e4 LT |
449 | { |
450 | switch (addr_hint) { | |
451 | case RTN_LOCAL: | |
91df42be | 452 | pr_debug("arp called for own IP address\n"); |
1da177e4 LT |
453 | memcpy(haddr, dev->dev_addr, dev->addr_len); |
454 | return 1; | |
455 | case RTN_MULTICAST: | |
456 | arp_mc_map(paddr, haddr, dev, 1); | |
457 | return 1; | |
458 | case RTN_BROADCAST: | |
459 | memcpy(haddr, dev->broadcast, dev->addr_len); | |
460 | return 1; | |
461 | } | |
462 | return 0; | |
463 | } | |
464 | ||
465 | ||
466 | int arp_find(unsigned char *haddr, struct sk_buff *skb) | |
467 | { | |
468 | struct net_device *dev = skb->dev; | |
fd683222 | 469 | __be32 paddr; |
1da177e4 LT |
470 | struct neighbour *n; |
471 | ||
adf30907 | 472 | if (!skb_dst(skb)) { |
91df42be | 473 | pr_debug("arp_find is called with dst==NULL\n"); |
1da177e4 LT |
474 | kfree_skb(skb); |
475 | return 1; | |
476 | } | |
477 | ||
f8126f1d | 478 | paddr = rt_nexthop(skb_rtable(skb), ip_hdr(skb)->daddr); |
deffd777 CG |
479 | if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr, |
480 | paddr, dev)) | |
1da177e4 LT |
481 | return 0; |
482 | ||
483 | n = __neigh_lookup(&arp_tbl, &paddr, dev, 1); | |
484 | ||
485 | if (n) { | |
486 | n->used = jiffies; | |
0ed8ddf4 ED |
487 | if (n->nud_state & NUD_VALID || neigh_event_send(n, skb) == 0) { |
488 | neigh_ha_snapshot(haddr, n, dev); | |
1da177e4 LT |
489 | neigh_release(n); |
490 | return 0; | |
491 | } | |
492 | neigh_release(n); | |
493 | } else | |
494 | kfree_skb(skb); | |
495 | return 1; | |
496 | } | |
4bc2f18b | 497 | EXPORT_SYMBOL(arp_find); |
1da177e4 LT |
498 | |
499 | /* END OF OBSOLETE FUNCTIONS */ | |
500 | ||
1da177e4 LT |
501 | /* |
502 | * Check if we can use proxy ARP for this path | |
503 | */ | |
65324144 JDB |
504 | static inline int arp_fwd_proxy(struct in_device *in_dev, |
505 | struct net_device *dev, struct rtable *rt) | |
1da177e4 LT |
506 | { |
507 | struct in_device *out_dev; | |
508 | int imi, omi = -1; | |
509 | ||
d8d1f30b | 510 | if (rt->dst.dev == dev) |
65324144 JDB |
511 | return 0; |
512 | ||
1da177e4 LT |
513 | if (!IN_DEV_PROXY_ARP(in_dev)) |
514 | return 0; | |
deffd777 CG |
515 | imi = IN_DEV_MEDIUM_ID(in_dev); |
516 | if (imi == 0) | |
1da177e4 LT |
517 | return 1; |
518 | if (imi == -1) | |
519 | return 0; | |
520 | ||
521 | /* place to check for proxy_arp for routes */ | |
522 | ||
d8d1f30b | 523 | out_dev = __in_dev_get_rcu(rt->dst.dev); |
faa9dcf7 | 524 | if (out_dev) |
1da177e4 | 525 | omi = IN_DEV_MEDIUM_ID(out_dev); |
faa9dcf7 | 526 | |
a02cec21 | 527 | return omi != imi && omi != -1; |
1da177e4 LT |
528 | } |
529 | ||
65324144 JDB |
530 | /* |
531 | * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev) | |
532 | * | |
533 | * RFC3069 supports proxy arp replies back to the same interface. This | |
534 | * is done to support (ethernet) switch features, like RFC 3069, where | |
535 | * the individual ports are not allowed to communicate with each | |
536 | * other, BUT they are allowed to talk to the upstream router. As | |
537 | * described in RFC 3069, it is possible to allow these hosts to | |
538 | * communicate through the upstream router, by proxy_arp'ing. | |
539 | * | |
540 | * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation" | |
541 | * | |
542 | * This technology is known by different names: | |
543 | * In RFC 3069 it is called VLAN Aggregation. | |
544 | * Cisco and Allied Telesyn call it Private VLAN. | |
545 | * Hewlett-Packard call it Source-Port filtering or port-isolation. | |
546 | * Ericsson call it MAC-Forced Forwarding (RFC Draft). | |
547 | * | |
548 | */ | |
549 | static inline int arp_fwd_pvlan(struct in_device *in_dev, | |
550 | struct net_device *dev, struct rtable *rt, | |
551 | __be32 sip, __be32 tip) | |
552 | { | |
553 | /* Private VLAN is only concerned about the same ethernet segment */ | |
d8d1f30b | 554 | if (rt->dst.dev != dev) |
65324144 JDB |
555 | return 0; |
556 | ||
557 | /* Don't reply on self probes (often done by windowz boxes)*/ | |
558 | if (sip == tip) | |
559 | return 0; | |
560 | ||
561 | if (IN_DEV_PROXY_ARP_PVLAN(in_dev)) | |
562 | return 1; | |
563 | else | |
564 | return 0; | |
565 | } | |
566 | ||
1da177e4 LT |
567 | /* |
568 | * Interface to link layer: send routine and receive handler. | |
569 | */ | |
570 | ||
571 | /* | |
572 | * Create an arp packet. If (dest_hw == NULL), we create a broadcast | |
573 | * message. | |
574 | */ | |
ed9bad06 AV |
575 | struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, |
576 | struct net_device *dev, __be32 src_ip, | |
abfdf1c4 JE |
577 | const unsigned char *dest_hw, |
578 | const unsigned char *src_hw, | |
579 | const unsigned char *target_hw) | |
1da177e4 LT |
580 | { |
581 | struct sk_buff *skb; | |
582 | struct arphdr *arp; | |
583 | unsigned char *arp_ptr; | |
66088243 HX |
584 | int hlen = LL_RESERVED_SPACE(dev); |
585 | int tlen = dev->needed_tailroom; | |
1da177e4 LT |
586 | |
587 | /* | |
588 | * Allocate a buffer | |
589 | */ | |
e905a9ed | 590 | |
66088243 | 591 | skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC); |
1da177e4 LT |
592 | if (skb == NULL) |
593 | return NULL; | |
594 | ||
66088243 | 595 | skb_reserve(skb, hlen); |
c1d2bbe1 | 596 | skb_reset_network_header(skb); |
988b7050 | 597 | arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev)); |
1da177e4 LT |
598 | skb->dev = dev; |
599 | skb->protocol = htons(ETH_P_ARP); | |
600 | if (src_hw == NULL) | |
601 | src_hw = dev->dev_addr; | |
602 | if (dest_hw == NULL) | |
603 | dest_hw = dev->broadcast; | |
604 | ||
605 | /* | |
606 | * Fill the device header for the ARP frame | |
607 | */ | |
0c4e8581 | 608 | if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) |
1da177e4 LT |
609 | goto out; |
610 | ||
611 | /* | |
612 | * Fill out the arp protocol part. | |
613 | * | |
614 | * The arp hardware type should match the device type, except for FDDI, | |
615 | * which (according to RFC 1390) should always equal 1 (Ethernet). | |
616 | */ | |
617 | /* | |
618 | * Exceptions everywhere. AX.25 uses the AX.25 PID value not the | |
619 | * DIX code for the protocol. Make these device structure fields. | |
620 | */ | |
621 | switch (dev->type) { | |
622 | default: | |
623 | arp->ar_hrd = htons(dev->type); | |
624 | arp->ar_pro = htons(ETH_P_IP); | |
625 | break; | |
626 | ||
40e4783e | 627 | #if IS_ENABLED(CONFIG_AX25) |
1da177e4 LT |
628 | case ARPHRD_AX25: |
629 | arp->ar_hrd = htons(ARPHRD_AX25); | |
630 | arp->ar_pro = htons(AX25_P_IP); | |
631 | break; | |
632 | ||
40e4783e | 633 | #if IS_ENABLED(CONFIG_NETROM) |
1da177e4 LT |
634 | case ARPHRD_NETROM: |
635 | arp->ar_hrd = htons(ARPHRD_NETROM); | |
636 | arp->ar_pro = htons(AX25_P_IP); | |
637 | break; | |
638 | #endif | |
639 | #endif | |
640 | ||
40e4783e | 641 | #if IS_ENABLED(CONFIG_FDDI) |
1da177e4 LT |
642 | case ARPHRD_FDDI: |
643 | arp->ar_hrd = htons(ARPHRD_ETHER); | |
644 | arp->ar_pro = htons(ETH_P_IP); | |
645 | break; | |
1da177e4 LT |
646 | #endif |
647 | } | |
648 | ||
649 | arp->ar_hln = dev->addr_len; | |
650 | arp->ar_pln = 4; | |
651 | arp->ar_op = htons(type); | |
652 | ||
deffd777 | 653 | arp_ptr = (unsigned char *)(arp + 1); |
1da177e4 LT |
654 | |
655 | memcpy(arp_ptr, src_hw, dev->addr_len); | |
f4cca7ff JK |
656 | arp_ptr += dev->addr_len; |
657 | memcpy(arp_ptr, &src_ip, 4); | |
658 | arp_ptr += 4; | |
1da177e4 LT |
659 | if (target_hw != NULL) |
660 | memcpy(arp_ptr, target_hw, dev->addr_len); | |
661 | else | |
662 | memset(arp_ptr, 0, dev->addr_len); | |
f4cca7ff | 663 | arp_ptr += dev->addr_len; |
1da177e4 LT |
664 | memcpy(arp_ptr, &dest_ip, 4); |
665 | ||
666 | return skb; | |
667 | ||
668 | out: | |
669 | kfree_skb(skb); | |
670 | return NULL; | |
671 | } | |
4bc2f18b | 672 | EXPORT_SYMBOL(arp_create); |
1da177e4 LT |
673 | |
674 | /* | |
675 | * Send an arp packet. | |
676 | */ | |
677 | void arp_xmit(struct sk_buff *skb) | |
678 | { | |
679 | /* Send it off, maybe filter it using firewalling first. */ | |
fdc9314c | 680 | NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit); |
1da177e4 | 681 | } |
4bc2f18b | 682 | EXPORT_SYMBOL(arp_xmit); |
1da177e4 LT |
683 | |
684 | /* | |
685 | * Create and send an arp packet. | |
686 | */ | |
ed9bad06 AV |
687 | void arp_send(int type, int ptype, __be32 dest_ip, |
688 | struct net_device *dev, __be32 src_ip, | |
abfdf1c4 JE |
689 | const unsigned char *dest_hw, const unsigned char *src_hw, |
690 | const unsigned char *target_hw) | |
1da177e4 LT |
691 | { |
692 | struct sk_buff *skb; | |
693 | ||
694 | /* | |
695 | * No arp on this interface. | |
696 | */ | |
e905a9ed | 697 | |
1da177e4 LT |
698 | if (dev->flags&IFF_NOARP) |
699 | return; | |
700 | ||
701 | skb = arp_create(type, ptype, dest_ip, dev, src_ip, | |
702 | dest_hw, src_hw, target_hw); | |
deffd777 | 703 | if (skb == NULL) |
1da177e4 | 704 | return; |
1da177e4 LT |
705 | |
706 | arp_xmit(skb); | |
707 | } | |
4bc2f18b | 708 | EXPORT_SYMBOL(arp_send); |
1da177e4 | 709 | |
1da177e4 LT |
710 | /* |
711 | * Process an arp request. | |
712 | */ | |
713 | ||
714 | static int arp_process(struct sk_buff *skb) | |
715 | { | |
716 | struct net_device *dev = skb->dev; | |
faa9dcf7 | 717 | struct in_device *in_dev = __in_dev_get_rcu(dev); |
1da177e4 LT |
718 | struct arphdr *arp; |
719 | unsigned char *arp_ptr; | |
720 | struct rtable *rt; | |
e0260fed | 721 | unsigned char *sha; |
9e12bb22 | 722 | __be32 sip, tip; |
1da177e4 LT |
723 | u16 dev_type = dev->type; |
724 | int addr_type; | |
725 | struct neighbour *n; | |
c346dca1 | 726 | struct net *net = dev_net(dev); |
1da177e4 LT |
727 | |
728 | /* arp_rcv below verifies the ARP header and verifies the device | |
729 | * is ARP'able. | |
730 | */ | |
731 | ||
732 | if (in_dev == NULL) | |
733 | goto out; | |
734 | ||
d0a92be0 | 735 | arp = arp_hdr(skb); |
1da177e4 LT |
736 | |
737 | switch (dev_type) { | |
e905a9ed | 738 | default: |
1da177e4 LT |
739 | if (arp->ar_pro != htons(ETH_P_IP) || |
740 | htons(dev_type) != arp->ar_hrd) | |
741 | goto out; | |
742 | break; | |
1da177e4 | 743 | case ARPHRD_ETHER: |
1da177e4 | 744 | case ARPHRD_FDDI: |
1da177e4 | 745 | case ARPHRD_IEEE802: |
1da177e4 | 746 | /* |
211ed865 | 747 | * ETHERNET, and Fibre Channel (which are IEEE 802 |
1da177e4 LT |
748 | * devices, according to RFC 2625) devices will accept ARP |
749 | * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). | |
750 | * This is the case also of FDDI, where the RFC 1390 says that | |
751 | * FDDI devices should accept ARP hardware of (1) Ethernet, | |
752 | * however, to be more robust, we'll accept both 1 (Ethernet) | |
753 | * or 6 (IEEE 802.2) | |
754 | */ | |
755 | if ((arp->ar_hrd != htons(ARPHRD_ETHER) && | |
756 | arp->ar_hrd != htons(ARPHRD_IEEE802)) || | |
757 | arp->ar_pro != htons(ETH_P_IP)) | |
758 | goto out; | |
759 | break; | |
1da177e4 LT |
760 | case ARPHRD_AX25: |
761 | if (arp->ar_pro != htons(AX25_P_IP) || | |
762 | arp->ar_hrd != htons(ARPHRD_AX25)) | |
763 | goto out; | |
764 | break; | |
1da177e4 LT |
765 | case ARPHRD_NETROM: |
766 | if (arp->ar_pro != htons(AX25_P_IP) || | |
767 | arp->ar_hrd != htons(ARPHRD_NETROM)) | |
768 | goto out; | |
769 | break; | |
1da177e4 LT |
770 | } |
771 | ||
772 | /* Understand only these message types */ | |
773 | ||
774 | if (arp->ar_op != htons(ARPOP_REPLY) && | |
775 | arp->ar_op != htons(ARPOP_REQUEST)) | |
776 | goto out; | |
777 | ||
778 | /* | |
779 | * Extract fields | |
780 | */ | |
deffd777 | 781 | arp_ptr = (unsigned char *)(arp + 1); |
1da177e4 LT |
782 | sha = arp_ptr; |
783 | arp_ptr += dev->addr_len; | |
784 | memcpy(&sip, arp_ptr, 4); | |
785 | arp_ptr += 4; | |
1da177e4 LT |
786 | arp_ptr += dev->addr_len; |
787 | memcpy(&tip, arp_ptr, 4); | |
e905a9ed | 788 | /* |
1da177e4 LT |
789 | * Check for bad requests for 127.x.x.x and requests for multicast |
790 | * addresses. If this is one such, delete it. | |
791 | */ | |
d0daebc3 TG |
792 | if (ipv4_is_multicast(tip) || |
793 | (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip))) | |
1da177e4 LT |
794 | goto out; |
795 | ||
796 | /* | |
797 | * Special case: We must set Frame Relay source Q.922 address | |
798 | */ | |
799 | if (dev_type == ARPHRD_DLCI) | |
800 | sha = dev->broadcast; | |
801 | ||
802 | /* | |
803 | * Process entry. The idea here is we want to send a reply if it is a | |
804 | * request for us or if it is a request for someone else that we hold | |
805 | * a proxy for. We want to add an entry to our cache if it is a reply | |
e905a9ed YH |
806 | * to us or if it is a request for our address. |
807 | * (The assumption for this last is that if someone is requesting our | |
808 | * address, they are probably intending to talk to us, so it saves time | |
809 | * if we cache their address. Their address is also probably not in | |
1da177e4 | 810 | * our cache, since ours is not in their cache.) |
e905a9ed | 811 | * |
1da177e4 LT |
812 | * Putting this another way, we only care about replies if they are to |
813 | * us, in which case we add them to the cache. For requests, we care | |
814 | * about those for us and those for our proxies. We reply to both, | |
e905a9ed | 815 | * and in the case of requests for us we add the requester to the arp |
1da177e4 LT |
816 | * cache. |
817 | */ | |
818 | ||
f8a68e75 EB |
819 | /* Special case: IPv4 duplicate address detection packet (RFC2131) */ |
820 | if (sip == 0) { | |
1da177e4 | 821 | if (arp->ar_op == htons(ARPOP_REQUEST) && |
49e8a279 | 822 | inet_addr_type(net, tip) == RTN_LOCAL && |
9bd85e32 | 823 | !arp_ignore(in_dev, sip, tip)) |
b4a9811c JD |
824 | arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha, |
825 | dev->dev_addr, sha); | |
1da177e4 LT |
826 | goto out; |
827 | } | |
828 | ||
829 | if (arp->ar_op == htons(ARPOP_REQUEST) && | |
c6cffba4 | 830 | ip_route_input_noref(skb, tip, sip, 0, dev) == 0) { |
1da177e4 | 831 | |
511c3f92 | 832 | rt = skb_rtable(skb); |
1da177e4 LT |
833 | addr_type = rt->rt_type; |
834 | ||
835 | if (addr_type == RTN_LOCAL) { | |
deffd777 | 836 | int dont_send; |
8164f1b7 | 837 | |
deffd777 | 838 | dont_send = arp_ignore(in_dev, sip, tip); |
8164f1b7 | 839 | if (!dont_send && IN_DEV_ARPFILTER(in_dev)) |
ae9c416d | 840 | dont_send = arp_filter(sip, tip, dev); |
8164f1b7 BG |
841 | if (!dont_send) { |
842 | n = neigh_event_ns(&arp_tbl, sha, &sip, dev); | |
843 | if (n) { | |
deffd777 CG |
844 | arp_send(ARPOP_REPLY, ETH_P_ARP, sip, |
845 | dev, tip, sha, dev->dev_addr, | |
846 | sha); | |
8164f1b7 BG |
847 | neigh_release(n); |
848 | } | |
1da177e4 LT |
849 | } |
850 | goto out; | |
851 | } else if (IN_DEV_FORWARD(in_dev)) { | |
65324144 JDB |
852 | if (addr_type == RTN_UNICAST && |
853 | (arp_fwd_proxy(in_dev, dev, rt) || | |
854 | arp_fwd_pvlan(in_dev, dev, rt, sip, tip) || | |
70620c46 TG |
855 | (rt->dst.dev != dev && |
856 | pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) { | |
1da177e4 LT |
857 | n = neigh_event_ns(&arp_tbl, sha, &sip, dev); |
858 | if (n) | |
859 | neigh_release(n); | |
860 | ||
e905a9ed | 861 | if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || |
1da177e4 LT |
862 | skb->pkt_type == PACKET_HOST || |
863 | in_dev->arp_parms->proxy_delay == 0) { | |
deffd777 CG |
864 | arp_send(ARPOP_REPLY, ETH_P_ARP, sip, |
865 | dev, tip, sha, dev->dev_addr, | |
866 | sha); | |
1da177e4 | 867 | } else { |
deffd777 CG |
868 | pneigh_enqueue(&arp_tbl, |
869 | in_dev->arp_parms, skb); | |
1da177e4 LT |
870 | return 0; |
871 | } | |
872 | goto out; | |
873 | } | |
874 | } | |
875 | } | |
876 | ||
877 | /* Update our ARP tables */ | |
878 | ||
879 | n = __neigh_lookup(&arp_tbl, &sip, dev, 0); | |
880 | ||
124d37e9 | 881 | if (IN_DEV_ARP_ACCEPT(in_dev)) { |
abd596a4 NH |
882 | /* Unsolicited ARP is not accepted by default. |
883 | It is possible, that this option should be enabled for some | |
884 | devices (strip is candidate) | |
885 | */ | |
886 | if (n == NULL && | |
6d955180 OP |
887 | (arp->ar_op == htons(ARPOP_REPLY) || |
888 | (arp->ar_op == htons(ARPOP_REQUEST) && tip == sip)) && | |
49e8a279 | 889 | inet_addr_type(net, sip) == RTN_UNICAST) |
1b1ac759 | 890 | n = __neigh_lookup(&arp_tbl, &sip, dev, 1); |
abd596a4 | 891 | } |
1da177e4 LT |
892 | |
893 | if (n) { | |
894 | int state = NUD_REACHABLE; | |
895 | int override; | |
896 | ||
897 | /* If several different ARP replies follows back-to-back, | |
898 | use the FIRST one. It is possible, if several proxy | |
899 | agents are active. Taking the first reply prevents | |
900 | arp trashing and chooses the fastest router. | |
901 | */ | |
902 | override = time_after(jiffies, n->updated + n->parms->locktime); | |
903 | ||
904 | /* Broadcast replies and request packets | |
905 | do not assert neighbour reachability. | |
906 | */ | |
907 | if (arp->ar_op != htons(ARPOP_REPLY) || | |
908 | skb->pkt_type != PACKET_HOST) | |
909 | state = NUD_STALE; | |
deffd777 CG |
910 | neigh_update(n, sha, state, |
911 | override ? NEIGH_UPDATE_F_OVERRIDE : 0); | |
1da177e4 LT |
912 | neigh_release(n); |
913 | } | |
914 | ||
915 | out: | |
ead2ceb0 | 916 | consume_skb(skb); |
1da177e4 LT |
917 | return 0; |
918 | } | |
919 | ||
444fc8fc HX |
920 | static void parp_redo(struct sk_buff *skb) |
921 | { | |
922 | arp_process(skb); | |
923 | } | |
924 | ||
1da177e4 LT |
925 | |
926 | /* | |
927 | * Receive an arp request from the device layer. | |
928 | */ | |
929 | ||
6c97e72a AB |
930 | static int arp_rcv(struct sk_buff *skb, struct net_device *dev, |
931 | struct packet_type *pt, struct net_device *orig_dev) | |
1da177e4 LT |
932 | { |
933 | struct arphdr *arp; | |
934 | ||
935 | /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ | |
988b7050 | 936 | if (!pskb_may_pull(skb, arp_hdr_len(dev))) |
1da177e4 LT |
937 | goto freeskb; |
938 | ||
d0a92be0 | 939 | arp = arp_hdr(skb); |
1da177e4 LT |
940 | if (arp->ar_hln != dev->addr_len || |
941 | dev->flags & IFF_NOARP || | |
942 | skb->pkt_type == PACKET_OTHERHOST || | |
943 | skb->pkt_type == PACKET_LOOPBACK || | |
944 | arp->ar_pln != 4) | |
945 | goto freeskb; | |
946 | ||
deffd777 CG |
947 | skb = skb_share_check(skb, GFP_ATOMIC); |
948 | if (skb == NULL) | |
1da177e4 LT |
949 | goto out_of_mem; |
950 | ||
a61bbcf2 PM |
951 | memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); |
952 | ||
fdc9314c | 953 | return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process); |
1da177e4 LT |
954 | |
955 | freeskb: | |
956 | kfree_skb(skb); | |
957 | out_of_mem: | |
958 | return 0; | |
959 | } | |
960 | ||
961 | /* | |
962 | * User level interface (ioctl) | |
963 | */ | |
964 | ||
965 | /* | |
966 | * Set (create) an ARP cache entry. | |
967 | */ | |
968 | ||
32e569b7 | 969 | static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) |
f8b33fdf PE |
970 | { |
971 | if (dev == NULL) { | |
586f1211 | 972 | IPV4_DEVCONF_ALL(net, PROXY_ARP) = on; |
f8b33fdf PE |
973 | return 0; |
974 | } | |
c506653d ED |
975 | if (__in_dev_get_rtnl(dev)) { |
976 | IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on); | |
f8b33fdf PE |
977 | return 0; |
978 | } | |
979 | return -ENXIO; | |
980 | } | |
981 | ||
32e569b7 PE |
982 | static int arp_req_set_public(struct net *net, struct arpreq *r, |
983 | struct net_device *dev) | |
43dc1701 PE |
984 | { |
985 | __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; | |
986 | __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; | |
987 | ||
988 | if (mask && mask != htonl(0xFFFFFFFF)) | |
989 | return -EINVAL; | |
990 | if (!dev && (r->arp_flags & ATF_COM)) { | |
941666c2 | 991 | dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family, |
deffd777 | 992 | r->arp_ha.sa_data); |
43dc1701 PE |
993 | if (!dev) |
994 | return -ENODEV; | |
995 | } | |
996 | if (mask) { | |
2db82b53 | 997 | if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL) |
43dc1701 PE |
998 | return -ENOBUFS; |
999 | return 0; | |
1000 | } | |
f8b33fdf | 1001 | |
32e569b7 | 1002 | return arp_req_set_proxy(net, dev, 1); |
43dc1701 PE |
1003 | } |
1004 | ||
32e569b7 | 1005 | static int arp_req_set(struct net *net, struct arpreq *r, |
deffd777 | 1006 | struct net_device *dev) |
1da177e4 | 1007 | { |
43dc1701 | 1008 | __be32 ip; |
1da177e4 LT |
1009 | struct neighbour *neigh; |
1010 | int err; | |
1011 | ||
43dc1701 | 1012 | if (r->arp_flags & ATF_PUBL) |
32e569b7 | 1013 | return arp_req_set_public(net, r, dev); |
1da177e4 | 1014 | |
43dc1701 | 1015 | ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; |
1da177e4 LT |
1016 | if (r->arp_flags & ATF_PERM) |
1017 | r->arp_flags |= ATF_COM; | |
1018 | if (dev == NULL) { | |
78fbfd8a | 1019 | struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); |
b23dd4fe DM |
1020 | |
1021 | if (IS_ERR(rt)) | |
1022 | return PTR_ERR(rt); | |
d8d1f30b | 1023 | dev = rt->dst.dev; |
1da177e4 LT |
1024 | ip_rt_put(rt); |
1025 | if (!dev) | |
1026 | return -EINVAL; | |
1027 | } | |
1028 | switch (dev->type) { | |
40e4783e | 1029 | #if IS_ENABLED(CONFIG_FDDI) |
1da177e4 LT |
1030 | case ARPHRD_FDDI: |
1031 | /* | |
1032 | * According to RFC 1390, FDDI devices should accept ARP | |
1033 | * hardware types of 1 (Ethernet). However, to be more | |
1034 | * robust, we'll accept hardware types of either 1 (Ethernet) | |
1035 | * or 6 (IEEE 802.2). | |
1036 | */ | |
1037 | if (r->arp_ha.sa_family != ARPHRD_FDDI && | |
1038 | r->arp_ha.sa_family != ARPHRD_ETHER && | |
1039 | r->arp_ha.sa_family != ARPHRD_IEEE802) | |
1040 | return -EINVAL; | |
1041 | break; | |
1042 | #endif | |
1043 | default: | |
1044 | if (r->arp_ha.sa_family != dev->type) | |
1045 | return -EINVAL; | |
1046 | break; | |
1047 | } | |
1048 | ||
1049 | neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); | |
1050 | err = PTR_ERR(neigh); | |
1051 | if (!IS_ERR(neigh)) { | |
95c96174 | 1052 | unsigned int state = NUD_STALE; |
1da177e4 LT |
1053 | if (r->arp_flags & ATF_PERM) |
1054 | state = NUD_PERMANENT; | |
deffd777 | 1055 | err = neigh_update(neigh, (r->arp_flags & ATF_COM) ? |
e905a9ed | 1056 | r->arp_ha.sa_data : NULL, state, |
deffd777 | 1057 | NEIGH_UPDATE_F_OVERRIDE | |
1da177e4 LT |
1058 | NEIGH_UPDATE_F_ADMIN); |
1059 | neigh_release(neigh); | |
1060 | } | |
1061 | return err; | |
1062 | } | |
1063 | ||
95c96174 | 1064 | static unsigned int arp_state_to_flags(struct neighbour *neigh) |
1da177e4 | 1065 | { |
1da177e4 | 1066 | if (neigh->nud_state&NUD_PERMANENT) |
deffd777 | 1067 | return ATF_PERM | ATF_COM; |
1da177e4 | 1068 | else if (neigh->nud_state&NUD_VALID) |
deffd777 CG |
1069 | return ATF_COM; |
1070 | else | |
1071 | return 0; | |
1da177e4 LT |
1072 | } |
1073 | ||
1074 | /* | |
1075 | * Get an ARP cache entry. | |
1076 | */ | |
1077 | ||
1078 | static int arp_req_get(struct arpreq *r, struct net_device *dev) | |
1079 | { | |
ed9bad06 | 1080 | __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; |
1da177e4 LT |
1081 | struct neighbour *neigh; |
1082 | int err = -ENXIO; | |
1083 | ||
1084 | neigh = neigh_lookup(&arp_tbl, &ip, dev); | |
1085 | if (neigh) { | |
1086 | read_lock_bh(&neigh->lock); | |
1087 | memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); | |
1088 | r->arp_flags = arp_state_to_flags(neigh); | |
1089 | read_unlock_bh(&neigh->lock); | |
1090 | r->arp_ha.sa_family = dev->type; | |
1091 | strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); | |
1092 | neigh_release(neigh); | |
1093 | err = 0; | |
1094 | } | |
1095 | return err; | |
1096 | } | |
1097 | ||
545ecdc3 ML |
1098 | int arp_invalidate(struct net_device *dev, __be32 ip) |
1099 | { | |
1100 | struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); | |
1101 | int err = -ENXIO; | |
1102 | ||
1103 | if (neigh) { | |
1104 | if (neigh->nud_state & ~NUD_NOARP) | |
1105 | err = neigh_update(neigh, NULL, NUD_FAILED, | |
1106 | NEIGH_UPDATE_F_OVERRIDE| | |
1107 | NEIGH_UPDATE_F_ADMIN); | |
1108 | neigh_release(neigh); | |
1109 | } | |
1110 | ||
1111 | return err; | |
1112 | } | |
1113 | EXPORT_SYMBOL(arp_invalidate); | |
1114 | ||
32e569b7 PE |
1115 | static int arp_req_delete_public(struct net *net, struct arpreq *r, |
1116 | struct net_device *dev) | |
46479b43 PE |
1117 | { |
1118 | __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; | |
1119 | __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; | |
1120 | ||
1121 | if (mask == htonl(0xFFFFFFFF)) | |
2db82b53 | 1122 | return pneigh_delete(&arp_tbl, net, &ip, dev); |
46479b43 | 1123 | |
f8b33fdf PE |
1124 | if (mask) |
1125 | return -EINVAL; | |
1126 | ||
32e569b7 | 1127 | return arp_req_set_proxy(net, dev, 0); |
46479b43 PE |
1128 | } |
1129 | ||
32e569b7 | 1130 | static int arp_req_delete(struct net *net, struct arpreq *r, |
deffd777 | 1131 | struct net_device *dev) |
1da177e4 | 1132 | { |
46479b43 | 1133 | __be32 ip; |
1da177e4 | 1134 | |
46479b43 | 1135 | if (r->arp_flags & ATF_PUBL) |
32e569b7 | 1136 | return arp_req_delete_public(net, r, dev); |
1da177e4 | 1137 | |
46479b43 | 1138 | ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; |
1da177e4 | 1139 | if (dev == NULL) { |
78fbfd8a | 1140 | struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); |
b23dd4fe DM |
1141 | if (IS_ERR(rt)) |
1142 | return PTR_ERR(rt); | |
d8d1f30b | 1143 | dev = rt->dst.dev; |
1da177e4 LT |
1144 | ip_rt_put(rt); |
1145 | if (!dev) | |
1146 | return -EINVAL; | |
1147 | } | |
545ecdc3 | 1148 | return arp_invalidate(dev, ip); |
1da177e4 LT |
1149 | } |
1150 | ||
1151 | /* | |
1152 | * Handle an ARP layer I/O control request. | |
1153 | */ | |
1154 | ||
32e569b7 | 1155 | int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) |
1da177e4 LT |
1156 | { |
1157 | int err; | |
1158 | struct arpreq r; | |
1159 | struct net_device *dev = NULL; | |
1160 | ||
1161 | switch (cmd) { | |
deffd777 CG |
1162 | case SIOCDARP: |
1163 | case SIOCSARP: | |
52e804c6 | 1164 | if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) |
deffd777 CG |
1165 | return -EPERM; |
1166 | case SIOCGARP: | |
1167 | err = copy_from_user(&r, arg, sizeof(struct arpreq)); | |
1168 | if (err) | |
1169 | return -EFAULT; | |
1170 | break; | |
1171 | default: | |
1172 | return -EINVAL; | |
1da177e4 LT |
1173 | } |
1174 | ||
1175 | if (r.arp_pa.sa_family != AF_INET) | |
1176 | return -EPFNOSUPPORT; | |
1177 | ||
1178 | if (!(r.arp_flags & ATF_PUBL) && | |
deffd777 | 1179 | (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB))) |
1da177e4 LT |
1180 | return -EINVAL; |
1181 | if (!(r.arp_flags & ATF_NETMASK)) | |
1182 | ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = | |
1183 | htonl(0xFFFFFFFFUL); | |
c506653d | 1184 | rtnl_lock(); |
1da177e4 LT |
1185 | if (r.arp_dev[0]) { |
1186 | err = -ENODEV; | |
c506653d | 1187 | dev = __dev_get_by_name(net, r.arp_dev); |
deffd777 | 1188 | if (dev == NULL) |
1da177e4 LT |
1189 | goto out; |
1190 | ||
1191 | /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ | |
1192 | if (!r.arp_ha.sa_family) | |
1193 | r.arp_ha.sa_family = dev->type; | |
1194 | err = -EINVAL; | |
1195 | if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) | |
1196 | goto out; | |
1197 | } else if (cmd == SIOCGARP) { | |
1198 | err = -ENODEV; | |
1199 | goto out; | |
1200 | } | |
1201 | ||
132adf54 | 1202 | switch (cmd) { |
1da177e4 | 1203 | case SIOCDARP: |
32e569b7 | 1204 | err = arp_req_delete(net, &r, dev); |
1da177e4 LT |
1205 | break; |
1206 | case SIOCSARP: | |
32e569b7 | 1207 | err = arp_req_set(net, &r, dev); |
1da177e4 LT |
1208 | break; |
1209 | case SIOCGARP: | |
1210 | err = arp_req_get(&r, dev); | |
1da177e4 LT |
1211 | break; |
1212 | } | |
1213 | out: | |
c506653d | 1214 | rtnl_unlock(); |
941666c2 ED |
1215 | if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r))) |
1216 | err = -EFAULT; | |
1da177e4 LT |
1217 | return err; |
1218 | } | |
1219 | ||
deffd777 CG |
1220 | static int arp_netdev_event(struct notifier_block *this, unsigned long event, |
1221 | void *ptr) | |
1da177e4 LT |
1222 | { |
1223 | struct net_device *dev = ptr; | |
1224 | ||
1225 | switch (event) { | |
1226 | case NETDEV_CHANGEADDR: | |
1227 | neigh_changeaddr(&arp_tbl, dev); | |
bafa6d9d | 1228 | rt_cache_flush(dev_net(dev)); |
1da177e4 LT |
1229 | break; |
1230 | default: | |
1231 | break; | |
1232 | } | |
1233 | ||
1234 | return NOTIFY_DONE; | |
1235 | } | |
1236 | ||
1237 | static struct notifier_block arp_netdev_notifier = { | |
1238 | .notifier_call = arp_netdev_event, | |
1239 | }; | |
1240 | ||
1241 | /* Note, that it is not on notifier chain. | |
1242 | It is necessary, that this routine was called after route cache will be | |
1243 | flushed. | |
1244 | */ | |
1245 | void arp_ifdown(struct net_device *dev) | |
1246 | { | |
1247 | neigh_ifdown(&arp_tbl, dev); | |
1248 | } | |
1249 | ||
1250 | ||
1251 | /* | |
1252 | * Called once on startup. | |
1253 | */ | |
1254 | ||
7546dd97 | 1255 | static struct packet_type arp_packet_type __read_mostly = { |
09640e63 | 1256 | .type = cpu_to_be16(ETH_P_ARP), |
1da177e4 LT |
1257 | .func = arp_rcv, |
1258 | }; | |
1259 | ||
1260 | static int arp_proc_init(void); | |
1261 | ||
1262 | void __init arp_init(void) | |
1263 | { | |
1264 | neigh_table_init(&arp_tbl); | |
1265 | ||
1266 | dev_add_pack(&arp_packet_type); | |
1267 | arp_proc_init(); | |
1268 | #ifdef CONFIG_SYSCTL | |
54716e3b | 1269 | neigh_sysctl_register(NULL, &arp_tbl.parms, "ipv4", NULL); |
1da177e4 LT |
1270 | #endif |
1271 | register_netdevice_notifier(&arp_netdev_notifier); | |
1272 | } | |
1273 | ||
1274 | #ifdef CONFIG_PROC_FS | |
40e4783e | 1275 | #if IS_ENABLED(CONFIG_AX25) |
1da177e4 LT |
1276 | |
1277 | /* ------------------------------------------------------------------------ */ | |
1278 | /* | |
1279 | * ax25 -> ASCII conversion | |
1280 | */ | |
1281 | static char *ax2asc2(ax25_address *a, char *buf) | |
1282 | { | |
1283 | char c, *s; | |
1284 | int n; | |
1285 | ||
1286 | for (n = 0, s = buf; n < 6; n++) { | |
1287 | c = (a->ax25_call[n] >> 1) & 0x7F; | |
1288 | ||
deffd777 CG |
1289 | if (c != ' ') |
1290 | *s++ = c; | |
1da177e4 | 1291 | } |
e905a9ed | 1292 | |
1da177e4 | 1293 | *s++ = '-'; |
deffd777 CG |
1294 | n = (a->ax25_call[6] >> 1) & 0x0F; |
1295 | if (n > 9) { | |
1da177e4 LT |
1296 | *s++ = '1'; |
1297 | n -= 10; | |
1298 | } | |
e905a9ed | 1299 | |
1da177e4 LT |
1300 | *s++ = n + '0'; |
1301 | *s++ = '\0'; | |
1302 | ||
1303 | if (*buf == '\0' || *buf == '-') | |
deffd777 | 1304 | return "*"; |
1da177e4 LT |
1305 | |
1306 | return buf; | |
1da177e4 LT |
1307 | } |
1308 | #endif /* CONFIG_AX25 */ | |
1309 | ||
1310 | #define HBUFFERLEN 30 | |
1311 | ||
1312 | static void arp_format_neigh_entry(struct seq_file *seq, | |
1313 | struct neighbour *n) | |
1314 | { | |
1315 | char hbuffer[HBUFFERLEN]; | |
1da177e4 LT |
1316 | int k, j; |
1317 | char tbuf[16]; | |
1318 | struct net_device *dev = n->dev; | |
1319 | int hatype = dev->type; | |
1320 | ||
1321 | read_lock(&n->lock); | |
1322 | /* Convert hardware address to XX:XX:XX:XX ... form. */ | |
40e4783e | 1323 | #if IS_ENABLED(CONFIG_AX25) |
1da177e4 LT |
1324 | if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) |
1325 | ax2asc2((ax25_address *)n->ha, hbuffer); | |
1326 | else { | |
1327 | #endif | |
1328 | for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { | |
51f82a2b DC |
1329 | hbuffer[k++] = hex_asc_hi(n->ha[j]); |
1330 | hbuffer[k++] = hex_asc_lo(n->ha[j]); | |
1da177e4 LT |
1331 | hbuffer[k++] = ':'; |
1332 | } | |
a3e8ee68 | 1333 | if (k != 0) |
1334 | --k; | |
1335 | hbuffer[k] = 0; | |
40e4783e | 1336 | #if IS_ENABLED(CONFIG_AX25) |
1da177e4 LT |
1337 | } |
1338 | #endif | |
673d57e7 | 1339 | sprintf(tbuf, "%pI4", n->primary_key); |
1da177e4 LT |
1340 | seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", |
1341 | tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); | |
1342 | read_unlock(&n->lock); | |
1343 | } | |
1344 | ||
1345 | static void arp_format_pneigh_entry(struct seq_file *seq, | |
1346 | struct pneigh_entry *n) | |
1347 | { | |
1348 | struct net_device *dev = n->dev; | |
1349 | int hatype = dev ? dev->type : 0; | |
1350 | char tbuf[16]; | |
1351 | ||
673d57e7 | 1352 | sprintf(tbuf, "%pI4", n->key); |
1da177e4 LT |
1353 | seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", |
1354 | tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", | |
1355 | dev ? dev->name : "*"); | |
1356 | } | |
1357 | ||
1358 | static int arp_seq_show(struct seq_file *seq, void *v) | |
1359 | { | |
1360 | if (v == SEQ_START_TOKEN) { | |
1361 | seq_puts(seq, "IP address HW type Flags " | |
1362 | "HW address Mask Device\n"); | |
1363 | } else { | |
1364 | struct neigh_seq_state *state = seq->private; | |
1365 | ||
1366 | if (state->flags & NEIGH_SEQ_IS_PNEIGH) | |
1367 | arp_format_pneigh_entry(seq, v); | |
1368 | else | |
1369 | arp_format_neigh_entry(seq, v); | |
1370 | } | |
1371 | ||
1372 | return 0; | |
1373 | } | |
1374 | ||
1375 | static void *arp_seq_start(struct seq_file *seq, loff_t *pos) | |
1376 | { | |
1377 | /* Don't want to confuse "arp -a" w/ magic entries, | |
1378 | * so we tell the generic iterator to skip NUD_NOARP. | |
1379 | */ | |
1380 | return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); | |
1381 | } | |
1382 | ||
1383 | /* ------------------------------------------------------------------------ */ | |
1384 | ||
f690808e | 1385 | static const struct seq_operations arp_seq_ops = { |
deffd777 CG |
1386 | .start = arp_seq_start, |
1387 | .next = neigh_seq_next, | |
1388 | .stop = neigh_seq_stop, | |
1389 | .show = arp_seq_show, | |
1da177e4 LT |
1390 | }; |
1391 | ||
1392 | static int arp_seq_open(struct inode *inode, struct file *file) | |
1393 | { | |
426b5303 EB |
1394 | return seq_open_net(inode, file, &arp_seq_ops, |
1395 | sizeof(struct neigh_seq_state)); | |
1da177e4 LT |
1396 | } |
1397 | ||
9a32144e | 1398 | static const struct file_operations arp_seq_fops = { |
1da177e4 LT |
1399 | .owner = THIS_MODULE, |
1400 | .open = arp_seq_open, | |
1401 | .read = seq_read, | |
1402 | .llseek = seq_lseek, | |
426b5303 | 1403 | .release = seq_release_net, |
1da177e4 LT |
1404 | }; |
1405 | ||
ffc31d3d DL |
1406 | |
1407 | static int __net_init arp_net_init(struct net *net) | |
1da177e4 | 1408 | { |
ffc31d3d | 1409 | if (!proc_net_fops_create(net, "arp", S_IRUGO, &arp_seq_fops)) |
1da177e4 LT |
1410 | return -ENOMEM; |
1411 | return 0; | |
1412 | } | |
1413 | ||
ffc31d3d DL |
1414 | static void __net_exit arp_net_exit(struct net *net) |
1415 | { | |
1416 | proc_net_remove(net, "arp"); | |
1417 | } | |
1418 | ||
1419 | static struct pernet_operations arp_net_ops = { | |
1420 | .init = arp_net_init, | |
1421 | .exit = arp_net_exit, | |
1422 | }; | |
1423 | ||
1424 | static int __init arp_proc_init(void) | |
1425 | { | |
1426 | return register_pernet_subsys(&arp_net_ops); | |
1427 | } | |
1428 | ||
1da177e4 LT |
1429 | #else /* CONFIG_PROC_FS */ |
1430 | ||
1431 | static int __init arp_proc_init(void) | |
1432 | { | |
1433 | return 0; | |
1434 | } | |
1435 | ||
1436 | #endif /* CONFIG_PROC_FS */ |