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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); |
60395a20 | 125 | static bool arp_key_eq(const struct neighbour *n, const void *pkey); |
1da177e4 LT |
126 | static int arp_constructor(struct neighbour *neigh); |
127 | static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); | |
128 | static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); | |
129 | static void parp_redo(struct sk_buff *skb); | |
130 | ||
89d69d2b | 131 | static const struct neigh_ops arp_generic_ops = { |
1da177e4 LT |
132 | .family = AF_INET, |
133 | .solicit = arp_solicit, | |
134 | .error_report = arp_error_report, | |
135 | .output = neigh_resolve_output, | |
136 | .connected_output = neigh_connected_output, | |
1da177e4 LT |
137 | }; |
138 | ||
89d69d2b | 139 | static const struct neigh_ops arp_hh_ops = { |
1da177e4 LT |
140 | .family = AF_INET, |
141 | .solicit = arp_solicit, | |
142 | .error_report = arp_error_report, | |
143 | .output = neigh_resolve_output, | |
144 | .connected_output = neigh_resolve_output, | |
1da177e4 LT |
145 | }; |
146 | ||
89d69d2b | 147 | static const struct neigh_ops arp_direct_ops = { |
1da177e4 | 148 | .family = AF_INET, |
8f40b161 DM |
149 | .output = neigh_direct_output, |
150 | .connected_output = neigh_direct_output, | |
1da177e4 LT |
151 | }; |
152 | ||
1da177e4 | 153 | struct neigh_table arp_tbl = { |
deffd777 | 154 | .family = AF_INET, |
deffd777 | 155 | .key_len = 4, |
bdf53c58 | 156 | .protocol = cpu_to_be16(ETH_P_IP), |
deffd777 | 157 | .hash = arp_hash, |
60395a20 | 158 | .key_eq = arp_key_eq, |
deffd777 CG |
159 | .constructor = arp_constructor, |
160 | .proxy_redo = parp_redo, | |
161 | .id = "arp_cache", | |
162 | .parms = { | |
163 | .tbl = &arp_tbl, | |
deffd777 | 164 | .reachable_time = 30 * HZ, |
1f9248e5 JP |
165 | .data = { |
166 | [NEIGH_VAR_MCAST_PROBES] = 3, | |
167 | [NEIGH_VAR_UCAST_PROBES] = 3, | |
168 | [NEIGH_VAR_RETRANS_TIME] = 1 * HZ, | |
169 | [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ, | |
170 | [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ, | |
171 | [NEIGH_VAR_GC_STALETIME] = 60 * HZ, | |
172 | [NEIGH_VAR_QUEUE_LEN_BYTES] = 64 * 1024, | |
173 | [NEIGH_VAR_PROXY_QLEN] = 64, | |
174 | [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ, | |
175 | [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10, | |
176 | [NEIGH_VAR_LOCKTIME] = 1 * HZ, | |
177 | }, | |
1da177e4 | 178 | }, |
deffd777 CG |
179 | .gc_interval = 30 * HZ, |
180 | .gc_thresh1 = 128, | |
181 | .gc_thresh2 = 512, | |
182 | .gc_thresh3 = 1024, | |
1da177e4 | 183 | }; |
4bc2f18b | 184 | EXPORT_SYMBOL(arp_tbl); |
1da177e4 | 185 | |
714e85be | 186 | int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir) |
1da177e4 LT |
187 | { |
188 | switch (dev->type) { | |
189 | case ARPHRD_ETHER: | |
190 | case ARPHRD_FDDI: | |
191 | case ARPHRD_IEEE802: | |
192 | ip_eth_mc_map(addr, haddr); | |
e905a9ed | 193 | return 0; |
1da177e4 | 194 | case ARPHRD_INFINIBAND: |
a9e527e3 | 195 | ip_ib_mc_map(addr, dev->broadcast, haddr); |
1da177e4 | 196 | return 0; |
93ca3bb5 TT |
197 | case ARPHRD_IPGRE: |
198 | ip_ipgre_mc_map(addr, dev->broadcast, haddr); | |
199 | return 0; | |
1da177e4 LT |
200 | default: |
201 | if (dir) { | |
202 | memcpy(haddr, dev->broadcast, dev->addr_len); | |
203 | return 0; | |
204 | } | |
205 | } | |
206 | return -EINVAL; | |
207 | } | |
208 | ||
209 | ||
d6bf7817 ED |
210 | static u32 arp_hash(const void *pkey, |
211 | const struct net_device *dev, | |
2c2aba6c | 212 | __u32 *hash_rnd) |
1da177e4 | 213 | { |
60395a20 EB |
214 | return arp_hashfn(pkey, dev, hash_rnd); |
215 | } | |
216 | ||
217 | static bool arp_key_eq(const struct neighbour *neigh, const void *pkey) | |
218 | { | |
219 | return neigh_key_eq32(neigh, pkey); | |
1da177e4 LT |
220 | } |
221 | ||
222 | static int arp_constructor(struct neighbour *neigh) | |
223 | { | |
deffd777 | 224 | __be32 addr = *(__be32 *)neigh->primary_key; |
1da177e4 LT |
225 | struct net_device *dev = neigh->dev; |
226 | struct in_device *in_dev; | |
227 | struct neigh_parms *parms; | |
228 | ||
1da177e4 | 229 | rcu_read_lock(); |
e5ed6399 | 230 | in_dev = __in_dev_get_rcu(dev); |
51456b29 | 231 | if (!in_dev) { |
1da177e4 LT |
232 | rcu_read_unlock(); |
233 | return -EINVAL; | |
234 | } | |
235 | ||
c346dca1 | 236 | neigh->type = inet_addr_type(dev_net(dev), addr); |
a79878f0 | 237 | |
1da177e4 LT |
238 | parms = in_dev->arp_parms; |
239 | __neigh_parms_put(neigh->parms); | |
240 | neigh->parms = neigh_parms_clone(parms); | |
241 | rcu_read_unlock(); | |
242 | ||
3b04ddde | 243 | if (!dev->header_ops) { |
1da177e4 LT |
244 | neigh->nud_state = NUD_NOARP; |
245 | neigh->ops = &arp_direct_ops; | |
8f40b161 | 246 | neigh->output = neigh_direct_output; |
1da177e4 LT |
247 | } else { |
248 | /* Good devices (checked by reading texts, but only Ethernet is | |
249 | tested) | |
250 | ||
251 | ARPHRD_ETHER: (ethernet, apfddi) | |
252 | ARPHRD_FDDI: (fddi) | |
253 | ARPHRD_IEEE802: (tr) | |
254 | ARPHRD_METRICOM: (strip) | |
255 | ARPHRD_ARCNET: | |
256 | etc. etc. etc. | |
257 | ||
258 | ARPHRD_IPDDP will also work, if author repairs it. | |
259 | I did not it, because this driver does not work even | |
260 | in old paradigm. | |
261 | */ | |
262 | ||
1da177e4 LT |
263 | if (neigh->type == RTN_MULTICAST) { |
264 | neigh->nud_state = NUD_NOARP; | |
265 | arp_mc_map(addr, neigh->ha, dev, 1); | |
deffd777 | 266 | } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) { |
1da177e4 LT |
267 | neigh->nud_state = NUD_NOARP; |
268 | memcpy(neigh->ha, dev->dev_addr, dev->addr_len); | |
deffd777 CG |
269 | } else if (neigh->type == RTN_BROADCAST || |
270 | (dev->flags & IFF_POINTOPOINT)) { | |
1da177e4 LT |
271 | neigh->nud_state = NUD_NOARP; |
272 | memcpy(neigh->ha, dev->broadcast, dev->addr_len); | |
273 | } | |
3b04ddde SH |
274 | |
275 | if (dev->header_ops->cache) | |
1da177e4 LT |
276 | neigh->ops = &arp_hh_ops; |
277 | else | |
278 | neigh->ops = &arp_generic_ops; | |
3b04ddde | 279 | |
deffd777 | 280 | if (neigh->nud_state & NUD_VALID) |
1da177e4 LT |
281 | neigh->output = neigh->ops->connected_output; |
282 | else | |
283 | neigh->output = neigh->ops->output; | |
284 | } | |
285 | return 0; | |
286 | } | |
287 | ||
288 | static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb) | |
289 | { | |
290 | dst_link_failure(skb); | |
291 | kfree_skb(skb); | |
292 | } | |
293 | ||
294 | static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb) | |
295 | { | |
a61ced5d | 296 | __be32 saddr = 0; |
cf0be880 | 297 | u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL; |
1da177e4 | 298 | struct net_device *dev = neigh->dev; |
deffd777 | 299 | __be32 target = *(__be32 *)neigh->primary_key; |
1da177e4 | 300 | int probes = atomic_read(&neigh->probes); |
4b4194c4 | 301 | struct in_device *in_dev; |
1da177e4 | 302 | |
4b4194c4 ED |
303 | rcu_read_lock(); |
304 | in_dev = __in_dev_get_rcu(dev); | |
305 | if (!in_dev) { | |
306 | rcu_read_unlock(); | |
1da177e4 | 307 | return; |
4b4194c4 | 308 | } |
1da177e4 LT |
309 | switch (IN_DEV_ARP_ANNOUNCE(in_dev)) { |
310 | default: | |
311 | case 0: /* By default announce any local IP */ | |
deffd777 CG |
312 | if (skb && inet_addr_type(dev_net(dev), |
313 | ip_hdr(skb)->saddr) == RTN_LOCAL) | |
eddc9ec5 | 314 | saddr = ip_hdr(skb)->saddr; |
1da177e4 LT |
315 | break; |
316 | case 1: /* Restrict announcements of saddr in same subnet */ | |
317 | if (!skb) | |
318 | break; | |
eddc9ec5 | 319 | saddr = ip_hdr(skb)->saddr; |
c346dca1 | 320 | if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) { |
1da177e4 LT |
321 | /* saddr should be known to target */ |
322 | if (inet_addr_onlink(in_dev, target, saddr)) | |
323 | break; | |
324 | } | |
325 | saddr = 0; | |
326 | break; | |
327 | case 2: /* Avoid secondary IPs, get a primary/preferred one */ | |
328 | break; | |
329 | } | |
4b4194c4 | 330 | rcu_read_unlock(); |
1da177e4 | 331 | |
1da177e4 LT |
332 | if (!saddr) |
333 | saddr = inet_select_addr(dev, target, RT_SCOPE_LINK); | |
334 | ||
1f9248e5 | 335 | probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES); |
deffd777 CG |
336 | if (probes < 0) { |
337 | if (!(neigh->nud_state & NUD_VALID)) | |
91df42be | 338 | pr_debug("trying to ucast probe in NUD_INVALID\n"); |
9650388b | 339 | neigh_ha_snapshot(dst_ha, neigh, dev); |
cf0be880 | 340 | dst_hw = dst_ha; |
deffd777 | 341 | } else { |
1f9248e5 | 342 | probes -= NEIGH_VAR(neigh->parms, APP_PROBES); |
deffd777 | 343 | if (probes < 0) { |
deffd777 | 344 | neigh_app_ns(neigh); |
deffd777 CG |
345 | return; |
346 | } | |
1da177e4 LT |
347 | } |
348 | ||
349 | arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr, | |
cf0be880 | 350 | dst_hw, dev->dev_addr, NULL); |
1da177e4 LT |
351 | } |
352 | ||
9bd85e32 | 353 | static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip) |
1da177e4 | 354 | { |
b601fa19 | 355 | struct net *net = dev_net(in_dev->dev); |
1da177e4 LT |
356 | int scope; |
357 | ||
358 | switch (IN_DEV_ARP_IGNORE(in_dev)) { | |
359 | case 0: /* Reply, the tip is already validated */ | |
360 | return 0; | |
361 | case 1: /* Reply only if tip is configured on the incoming interface */ | |
362 | sip = 0; | |
363 | scope = RT_SCOPE_HOST; | |
364 | break; | |
365 | case 2: /* | |
366 | * Reply only if tip is configured on the incoming interface | |
367 | * and is in same subnet as sip | |
368 | */ | |
369 | scope = RT_SCOPE_HOST; | |
370 | break; | |
371 | case 3: /* Do not reply for scope host addresses */ | |
372 | sip = 0; | |
373 | scope = RT_SCOPE_LINK; | |
b601fa19 | 374 | in_dev = NULL; |
1da177e4 LT |
375 | break; |
376 | case 4: /* Reserved */ | |
377 | case 5: | |
378 | case 6: | |
379 | case 7: | |
380 | return 0; | |
381 | case 8: /* Do not reply */ | |
382 | return 1; | |
383 | default: | |
384 | return 0; | |
385 | } | |
b601fa19 | 386 | return !inet_confirm_addr(net, in_dev, sip, tip, scope); |
1da177e4 LT |
387 | } |
388 | ||
ed9bad06 | 389 | static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev) |
1da177e4 | 390 | { |
1da177e4 | 391 | struct rtable *rt; |
e905a9ed | 392 | int flag = 0; |
1da177e4 | 393 | /*unsigned long now; */ |
ca12a1a4 | 394 | struct net *net = dev_net(dev); |
1da177e4 | 395 | |
78fbfd8a | 396 | rt = ip_route_output(net, sip, tip, 0, 0); |
b23dd4fe | 397 | if (IS_ERR(rt)) |
1da177e4 | 398 | return 1; |
d8d1f30b | 399 | if (rt->dst.dev != dev) { |
de0744af | 400 | NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER); |
1da177e4 | 401 | flag = 1; |
e905a9ed YH |
402 | } |
403 | ip_rt_put(rt); | |
404 | return flag; | |
405 | } | |
1da177e4 | 406 | |
1da177e4 LT |
407 | /* |
408 | * Check if we can use proxy ARP for this path | |
409 | */ | |
65324144 JDB |
410 | static inline int arp_fwd_proxy(struct in_device *in_dev, |
411 | struct net_device *dev, struct rtable *rt) | |
1da177e4 LT |
412 | { |
413 | struct in_device *out_dev; | |
414 | int imi, omi = -1; | |
415 | ||
d8d1f30b | 416 | if (rt->dst.dev == dev) |
65324144 JDB |
417 | return 0; |
418 | ||
1da177e4 LT |
419 | if (!IN_DEV_PROXY_ARP(in_dev)) |
420 | return 0; | |
deffd777 CG |
421 | imi = IN_DEV_MEDIUM_ID(in_dev); |
422 | if (imi == 0) | |
1da177e4 LT |
423 | return 1; |
424 | if (imi == -1) | |
425 | return 0; | |
426 | ||
427 | /* place to check for proxy_arp for routes */ | |
428 | ||
d8d1f30b | 429 | out_dev = __in_dev_get_rcu(rt->dst.dev); |
faa9dcf7 | 430 | if (out_dev) |
1da177e4 | 431 | omi = IN_DEV_MEDIUM_ID(out_dev); |
faa9dcf7 | 432 | |
a02cec21 | 433 | return omi != imi && omi != -1; |
1da177e4 LT |
434 | } |
435 | ||
65324144 JDB |
436 | /* |
437 | * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev) | |
438 | * | |
439 | * RFC3069 supports proxy arp replies back to the same interface. This | |
440 | * is done to support (ethernet) switch features, like RFC 3069, where | |
441 | * the individual ports are not allowed to communicate with each | |
442 | * other, BUT they are allowed to talk to the upstream router. As | |
443 | * described in RFC 3069, it is possible to allow these hosts to | |
444 | * communicate through the upstream router, by proxy_arp'ing. | |
445 | * | |
446 | * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation" | |
447 | * | |
448 | * This technology is known by different names: | |
449 | * In RFC 3069 it is called VLAN Aggregation. | |
450 | * Cisco and Allied Telesyn call it Private VLAN. | |
451 | * Hewlett-Packard call it Source-Port filtering or port-isolation. | |
452 | * Ericsson call it MAC-Forced Forwarding (RFC Draft). | |
453 | * | |
454 | */ | |
455 | static inline int arp_fwd_pvlan(struct in_device *in_dev, | |
456 | struct net_device *dev, struct rtable *rt, | |
457 | __be32 sip, __be32 tip) | |
458 | { | |
459 | /* Private VLAN is only concerned about the same ethernet segment */ | |
d8d1f30b | 460 | if (rt->dst.dev != dev) |
65324144 JDB |
461 | return 0; |
462 | ||
463 | /* Don't reply on self probes (often done by windowz boxes)*/ | |
464 | if (sip == tip) | |
465 | return 0; | |
466 | ||
467 | if (IN_DEV_PROXY_ARP_PVLAN(in_dev)) | |
468 | return 1; | |
469 | else | |
470 | return 0; | |
471 | } | |
472 | ||
1da177e4 LT |
473 | /* |
474 | * Interface to link layer: send routine and receive handler. | |
475 | */ | |
476 | ||
477 | /* | |
51456b29 | 478 | * Create an arp packet. If dest_hw is not set, we create a broadcast |
1da177e4 LT |
479 | * message. |
480 | */ | |
ed9bad06 AV |
481 | struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, |
482 | struct net_device *dev, __be32 src_ip, | |
abfdf1c4 JE |
483 | const unsigned char *dest_hw, |
484 | const unsigned char *src_hw, | |
485 | const unsigned char *target_hw) | |
1da177e4 LT |
486 | { |
487 | struct sk_buff *skb; | |
488 | struct arphdr *arp; | |
489 | unsigned char *arp_ptr; | |
66088243 HX |
490 | int hlen = LL_RESERVED_SPACE(dev); |
491 | int tlen = dev->needed_tailroom; | |
1da177e4 LT |
492 | |
493 | /* | |
494 | * Allocate a buffer | |
495 | */ | |
e905a9ed | 496 | |
66088243 | 497 | skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC); |
51456b29 | 498 | if (!skb) |
1da177e4 LT |
499 | return NULL; |
500 | ||
66088243 | 501 | skb_reserve(skb, hlen); |
c1d2bbe1 | 502 | skb_reset_network_header(skb); |
988b7050 | 503 | arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev)); |
1da177e4 LT |
504 | skb->dev = dev; |
505 | skb->protocol = htons(ETH_P_ARP); | |
51456b29 | 506 | if (!src_hw) |
1da177e4 | 507 | src_hw = dev->dev_addr; |
51456b29 | 508 | if (!dest_hw) |
1da177e4 LT |
509 | dest_hw = dev->broadcast; |
510 | ||
511 | /* | |
512 | * Fill the device header for the ARP frame | |
513 | */ | |
0c4e8581 | 514 | if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0) |
1da177e4 LT |
515 | goto out; |
516 | ||
517 | /* | |
518 | * Fill out the arp protocol part. | |
519 | * | |
520 | * The arp hardware type should match the device type, except for FDDI, | |
521 | * which (according to RFC 1390) should always equal 1 (Ethernet). | |
522 | */ | |
523 | /* | |
524 | * Exceptions everywhere. AX.25 uses the AX.25 PID value not the | |
525 | * DIX code for the protocol. Make these device structure fields. | |
526 | */ | |
527 | switch (dev->type) { | |
528 | default: | |
529 | arp->ar_hrd = htons(dev->type); | |
530 | arp->ar_pro = htons(ETH_P_IP); | |
531 | break; | |
532 | ||
40e4783e | 533 | #if IS_ENABLED(CONFIG_AX25) |
1da177e4 LT |
534 | case ARPHRD_AX25: |
535 | arp->ar_hrd = htons(ARPHRD_AX25); | |
536 | arp->ar_pro = htons(AX25_P_IP); | |
537 | break; | |
538 | ||
40e4783e | 539 | #if IS_ENABLED(CONFIG_NETROM) |
1da177e4 LT |
540 | case ARPHRD_NETROM: |
541 | arp->ar_hrd = htons(ARPHRD_NETROM); | |
542 | arp->ar_pro = htons(AX25_P_IP); | |
543 | break; | |
544 | #endif | |
545 | #endif | |
546 | ||
40e4783e | 547 | #if IS_ENABLED(CONFIG_FDDI) |
1da177e4 LT |
548 | case ARPHRD_FDDI: |
549 | arp->ar_hrd = htons(ARPHRD_ETHER); | |
550 | arp->ar_pro = htons(ETH_P_IP); | |
551 | break; | |
1da177e4 LT |
552 | #endif |
553 | } | |
554 | ||
555 | arp->ar_hln = dev->addr_len; | |
556 | arp->ar_pln = 4; | |
557 | arp->ar_op = htons(type); | |
558 | ||
deffd777 | 559 | arp_ptr = (unsigned char *)(arp + 1); |
1da177e4 LT |
560 | |
561 | memcpy(arp_ptr, src_hw, dev->addr_len); | |
f4cca7ff JK |
562 | arp_ptr += dev->addr_len; |
563 | memcpy(arp_ptr, &src_ip, 4); | |
564 | arp_ptr += 4; | |
6752c8db YH |
565 | |
566 | switch (dev->type) { | |
567 | #if IS_ENABLED(CONFIG_FIREWIRE_NET) | |
568 | case ARPHRD_IEEE1394: | |
569 | break; | |
570 | #endif | |
571 | default: | |
00db4124 | 572 | if (target_hw) |
6752c8db YH |
573 | memcpy(arp_ptr, target_hw, dev->addr_len); |
574 | else | |
575 | memset(arp_ptr, 0, dev->addr_len); | |
576 | arp_ptr += dev->addr_len; | |
577 | } | |
1da177e4 LT |
578 | memcpy(arp_ptr, &dest_ip, 4); |
579 | ||
580 | return skb; | |
581 | ||
582 | out: | |
583 | kfree_skb(skb); | |
584 | return NULL; | |
585 | } | |
4bc2f18b | 586 | EXPORT_SYMBOL(arp_create); |
1da177e4 LT |
587 | |
588 | /* | |
589 | * Send an arp packet. | |
590 | */ | |
591 | void arp_xmit(struct sk_buff *skb) | |
592 | { | |
593 | /* Send it off, maybe filter it using firewalling first. */ | |
7026b1dd DM |
594 | NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, NULL, skb, |
595 | NULL, skb->dev, dev_queue_xmit_sk); | |
1da177e4 | 596 | } |
4bc2f18b | 597 | EXPORT_SYMBOL(arp_xmit); |
1da177e4 LT |
598 | |
599 | /* | |
600 | * Create and send an arp packet. | |
601 | */ | |
ed9bad06 AV |
602 | void arp_send(int type, int ptype, __be32 dest_ip, |
603 | struct net_device *dev, __be32 src_ip, | |
abfdf1c4 JE |
604 | const unsigned char *dest_hw, const unsigned char *src_hw, |
605 | const unsigned char *target_hw) | |
1da177e4 LT |
606 | { |
607 | struct sk_buff *skb; | |
608 | ||
609 | /* | |
610 | * No arp on this interface. | |
611 | */ | |
e905a9ed | 612 | |
1da177e4 LT |
613 | if (dev->flags&IFF_NOARP) |
614 | return; | |
615 | ||
616 | skb = arp_create(type, ptype, dest_ip, dev, src_ip, | |
617 | dest_hw, src_hw, target_hw); | |
51456b29 | 618 | if (!skb) |
1da177e4 | 619 | return; |
1da177e4 LT |
620 | |
621 | arp_xmit(skb); | |
622 | } | |
4bc2f18b | 623 | EXPORT_SYMBOL(arp_send); |
1da177e4 | 624 | |
1da177e4 LT |
625 | /* |
626 | * Process an arp request. | |
627 | */ | |
628 | ||
7026b1dd | 629 | static int arp_process(struct sock *sk, struct sk_buff *skb) |
1da177e4 LT |
630 | { |
631 | struct net_device *dev = skb->dev; | |
faa9dcf7 | 632 | struct in_device *in_dev = __in_dev_get_rcu(dev); |
1da177e4 LT |
633 | struct arphdr *arp; |
634 | unsigned char *arp_ptr; | |
635 | struct rtable *rt; | |
e0260fed | 636 | unsigned char *sha; |
9e12bb22 | 637 | __be32 sip, tip; |
1da177e4 LT |
638 | u16 dev_type = dev->type; |
639 | int addr_type; | |
640 | struct neighbour *n; | |
c346dca1 | 641 | struct net *net = dev_net(dev); |
56022a8f | 642 | bool is_garp = false; |
1da177e4 LT |
643 | |
644 | /* arp_rcv below verifies the ARP header and verifies the device | |
645 | * is ARP'able. | |
646 | */ | |
647 | ||
51456b29 | 648 | if (!in_dev) |
1da177e4 LT |
649 | goto out; |
650 | ||
d0a92be0 | 651 | arp = arp_hdr(skb); |
1da177e4 LT |
652 | |
653 | switch (dev_type) { | |
e905a9ed | 654 | default: |
1da177e4 LT |
655 | if (arp->ar_pro != htons(ETH_P_IP) || |
656 | htons(dev_type) != arp->ar_hrd) | |
657 | goto out; | |
658 | break; | |
1da177e4 | 659 | case ARPHRD_ETHER: |
1da177e4 | 660 | case ARPHRD_FDDI: |
1da177e4 | 661 | case ARPHRD_IEEE802: |
1da177e4 | 662 | /* |
211ed865 | 663 | * ETHERNET, and Fibre Channel (which are IEEE 802 |
1da177e4 LT |
664 | * devices, according to RFC 2625) devices will accept ARP |
665 | * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2). | |
666 | * This is the case also of FDDI, where the RFC 1390 says that | |
667 | * FDDI devices should accept ARP hardware of (1) Ethernet, | |
668 | * however, to be more robust, we'll accept both 1 (Ethernet) | |
669 | * or 6 (IEEE 802.2) | |
670 | */ | |
671 | if ((arp->ar_hrd != htons(ARPHRD_ETHER) && | |
672 | arp->ar_hrd != htons(ARPHRD_IEEE802)) || | |
673 | arp->ar_pro != htons(ETH_P_IP)) | |
674 | goto out; | |
675 | break; | |
1da177e4 LT |
676 | case ARPHRD_AX25: |
677 | if (arp->ar_pro != htons(AX25_P_IP) || | |
678 | arp->ar_hrd != htons(ARPHRD_AX25)) | |
679 | goto out; | |
680 | break; | |
1da177e4 LT |
681 | case ARPHRD_NETROM: |
682 | if (arp->ar_pro != htons(AX25_P_IP) || | |
683 | arp->ar_hrd != htons(ARPHRD_NETROM)) | |
684 | goto out; | |
685 | break; | |
1da177e4 LT |
686 | } |
687 | ||
688 | /* Understand only these message types */ | |
689 | ||
690 | if (arp->ar_op != htons(ARPOP_REPLY) && | |
691 | arp->ar_op != htons(ARPOP_REQUEST)) | |
692 | goto out; | |
693 | ||
694 | /* | |
695 | * Extract fields | |
696 | */ | |
deffd777 | 697 | arp_ptr = (unsigned char *)(arp + 1); |
1da177e4 LT |
698 | sha = arp_ptr; |
699 | arp_ptr += dev->addr_len; | |
700 | memcpy(&sip, arp_ptr, 4); | |
701 | arp_ptr += 4; | |
6752c8db YH |
702 | switch (dev_type) { |
703 | #if IS_ENABLED(CONFIG_FIREWIRE_NET) | |
704 | case ARPHRD_IEEE1394: | |
705 | break; | |
706 | #endif | |
707 | default: | |
708 | arp_ptr += dev->addr_len; | |
709 | } | |
1da177e4 | 710 | memcpy(&tip, arp_ptr, 4); |
e905a9ed | 711 | /* |
1da177e4 LT |
712 | * Check for bad requests for 127.x.x.x and requests for multicast |
713 | * addresses. If this is one such, delete it. | |
714 | */ | |
d0daebc3 TG |
715 | if (ipv4_is_multicast(tip) || |
716 | (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip))) | |
1da177e4 LT |
717 | goto out; |
718 | ||
719 | /* | |
720 | * Special case: We must set Frame Relay source Q.922 address | |
721 | */ | |
722 | if (dev_type == ARPHRD_DLCI) | |
723 | sha = dev->broadcast; | |
724 | ||
725 | /* | |
726 | * Process entry. The idea here is we want to send a reply if it is a | |
727 | * request for us or if it is a request for someone else that we hold | |
728 | * a proxy for. We want to add an entry to our cache if it is a reply | |
e905a9ed YH |
729 | * to us or if it is a request for our address. |
730 | * (The assumption for this last is that if someone is requesting our | |
731 | * address, they are probably intending to talk to us, so it saves time | |
732 | * if we cache their address. Their address is also probably not in | |
1da177e4 | 733 | * our cache, since ours is not in their cache.) |
e905a9ed | 734 | * |
1da177e4 LT |
735 | * Putting this another way, we only care about replies if they are to |
736 | * us, in which case we add them to the cache. For requests, we care | |
737 | * about those for us and those for our proxies. We reply to both, | |
e905a9ed | 738 | * and in the case of requests for us we add the requester to the arp |
1da177e4 LT |
739 | * cache. |
740 | */ | |
741 | ||
f8a68e75 EB |
742 | /* Special case: IPv4 duplicate address detection packet (RFC2131) */ |
743 | if (sip == 0) { | |
1da177e4 | 744 | if (arp->ar_op == htons(ARPOP_REQUEST) && |
49e8a279 | 745 | inet_addr_type(net, tip) == RTN_LOCAL && |
9bd85e32 | 746 | !arp_ignore(in_dev, sip, tip)) |
b4a9811c JD |
747 | arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha, |
748 | dev->dev_addr, sha); | |
1da177e4 LT |
749 | goto out; |
750 | } | |
751 | ||
752 | if (arp->ar_op == htons(ARPOP_REQUEST) && | |
c6cffba4 | 753 | ip_route_input_noref(skb, tip, sip, 0, dev) == 0) { |
1da177e4 | 754 | |
511c3f92 | 755 | rt = skb_rtable(skb); |
1da177e4 LT |
756 | addr_type = rt->rt_type; |
757 | ||
758 | if (addr_type == RTN_LOCAL) { | |
deffd777 | 759 | int dont_send; |
8164f1b7 | 760 | |
deffd777 | 761 | dont_send = arp_ignore(in_dev, sip, tip); |
8164f1b7 | 762 | if (!dont_send && IN_DEV_ARPFILTER(in_dev)) |
ae9c416d | 763 | dont_send = arp_filter(sip, tip, dev); |
8164f1b7 BG |
764 | if (!dont_send) { |
765 | n = neigh_event_ns(&arp_tbl, sha, &sip, dev); | |
766 | if (n) { | |
deffd777 CG |
767 | arp_send(ARPOP_REPLY, ETH_P_ARP, sip, |
768 | dev, tip, sha, dev->dev_addr, | |
769 | sha); | |
8164f1b7 BG |
770 | neigh_release(n); |
771 | } | |
1da177e4 LT |
772 | } |
773 | goto out; | |
774 | } else if (IN_DEV_FORWARD(in_dev)) { | |
65324144 JDB |
775 | if (addr_type == RTN_UNICAST && |
776 | (arp_fwd_proxy(in_dev, dev, rt) || | |
777 | arp_fwd_pvlan(in_dev, dev, rt, sip, tip) || | |
70620c46 TG |
778 | (rt->dst.dev != dev && |
779 | pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) { | |
1da177e4 LT |
780 | n = neigh_event_ns(&arp_tbl, sha, &sip, dev); |
781 | if (n) | |
782 | neigh_release(n); | |
783 | ||
e905a9ed | 784 | if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED || |
1da177e4 | 785 | skb->pkt_type == PACKET_HOST || |
1f9248e5 | 786 | NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) { |
deffd777 CG |
787 | arp_send(ARPOP_REPLY, ETH_P_ARP, sip, |
788 | dev, tip, sha, dev->dev_addr, | |
789 | sha); | |
1da177e4 | 790 | } else { |
deffd777 CG |
791 | pneigh_enqueue(&arp_tbl, |
792 | in_dev->arp_parms, skb); | |
1da177e4 LT |
793 | return 0; |
794 | } | |
795 | goto out; | |
796 | } | |
797 | } | |
798 | } | |
799 | ||
800 | /* Update our ARP tables */ | |
801 | ||
802 | n = __neigh_lookup(&arp_tbl, &sip, dev, 0); | |
803 | ||
124d37e9 | 804 | if (IN_DEV_ARP_ACCEPT(in_dev)) { |
abd596a4 NH |
805 | /* Unsolicited ARP is not accepted by default. |
806 | It is possible, that this option should be enabled for some | |
807 | devices (strip is candidate) | |
808 | */ | |
56022a8f SN |
809 | is_garp = arp->ar_op == htons(ARPOP_REQUEST) && tip == sip && |
810 | inet_addr_type(net, sip) == RTN_UNICAST; | |
811 | ||
51456b29 | 812 | if (!n && |
56022a8f SN |
813 | ((arp->ar_op == htons(ARPOP_REPLY) && |
814 | inet_addr_type(net, sip) == RTN_UNICAST) || is_garp)) | |
1b1ac759 | 815 | n = __neigh_lookup(&arp_tbl, &sip, dev, 1); |
abd596a4 | 816 | } |
1da177e4 LT |
817 | |
818 | if (n) { | |
819 | int state = NUD_REACHABLE; | |
820 | int override; | |
821 | ||
822 | /* If several different ARP replies follows back-to-back, | |
823 | use the FIRST one. It is possible, if several proxy | |
824 | agents are active. Taking the first reply prevents | |
825 | arp trashing and chooses the fastest router. | |
826 | */ | |
56022a8f SN |
827 | override = time_after(jiffies, |
828 | n->updated + | |
829 | NEIGH_VAR(n->parms, LOCKTIME)) || | |
830 | is_garp; | |
1da177e4 LT |
831 | |
832 | /* Broadcast replies and request packets | |
833 | do not assert neighbour reachability. | |
834 | */ | |
835 | if (arp->ar_op != htons(ARPOP_REPLY) || | |
836 | skb->pkt_type != PACKET_HOST) | |
837 | state = NUD_STALE; | |
deffd777 CG |
838 | neigh_update(n, sha, state, |
839 | override ? NEIGH_UPDATE_F_OVERRIDE : 0); | |
1da177e4 LT |
840 | neigh_release(n); |
841 | } | |
842 | ||
843 | out: | |
ead2ceb0 | 844 | consume_skb(skb); |
1da177e4 LT |
845 | return 0; |
846 | } | |
847 | ||
444fc8fc HX |
848 | static void parp_redo(struct sk_buff *skb) |
849 | { | |
7026b1dd | 850 | arp_process(NULL, skb); |
444fc8fc HX |
851 | } |
852 | ||
1da177e4 LT |
853 | |
854 | /* | |
855 | * Receive an arp request from the device layer. | |
856 | */ | |
857 | ||
6c97e72a AB |
858 | static int arp_rcv(struct sk_buff *skb, struct net_device *dev, |
859 | struct packet_type *pt, struct net_device *orig_dev) | |
1da177e4 | 860 | { |
044453b3 ED |
861 | const struct arphdr *arp; |
862 | ||
825bae5d | 863 | /* do not tweak dropwatch on an ARP we will ignore */ |
044453b3 ED |
864 | if (dev->flags & IFF_NOARP || |
865 | skb->pkt_type == PACKET_OTHERHOST || | |
866 | skb->pkt_type == PACKET_LOOPBACK) | |
825bae5d | 867 | goto consumeskb; |
044453b3 ED |
868 | |
869 | skb = skb_share_check(skb, GFP_ATOMIC); | |
870 | if (!skb) | |
871 | goto out_of_mem; | |
1da177e4 LT |
872 | |
873 | /* ARP header, plus 2 device addresses, plus 2 IP addresses. */ | |
988b7050 | 874 | if (!pskb_may_pull(skb, arp_hdr_len(dev))) |
1da177e4 LT |
875 | goto freeskb; |
876 | ||
d0a92be0 | 877 | arp = arp_hdr(skb); |
044453b3 | 878 | if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4) |
1da177e4 LT |
879 | goto freeskb; |
880 | ||
a61bbcf2 PM |
881 | memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); |
882 | ||
7026b1dd DM |
883 | return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, NULL, skb, |
884 | dev, NULL, arp_process); | |
1da177e4 | 885 | |
825bae5d RJ |
886 | consumeskb: |
887 | consume_skb(skb); | |
888 | return 0; | |
1da177e4 LT |
889 | freeskb: |
890 | kfree_skb(skb); | |
891 | out_of_mem: | |
892 | return 0; | |
893 | } | |
894 | ||
895 | /* | |
896 | * User level interface (ioctl) | |
897 | */ | |
898 | ||
899 | /* | |
900 | * Set (create) an ARP cache entry. | |
901 | */ | |
902 | ||
32e569b7 | 903 | static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on) |
f8b33fdf | 904 | { |
51456b29 | 905 | if (!dev) { |
586f1211 | 906 | IPV4_DEVCONF_ALL(net, PROXY_ARP) = on; |
f8b33fdf PE |
907 | return 0; |
908 | } | |
c506653d ED |
909 | if (__in_dev_get_rtnl(dev)) { |
910 | IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on); | |
f8b33fdf PE |
911 | return 0; |
912 | } | |
913 | return -ENXIO; | |
914 | } | |
915 | ||
32e569b7 PE |
916 | static int arp_req_set_public(struct net *net, struct arpreq *r, |
917 | struct net_device *dev) | |
43dc1701 PE |
918 | { |
919 | __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; | |
920 | __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; | |
921 | ||
922 | if (mask && mask != htonl(0xFFFFFFFF)) | |
923 | return -EINVAL; | |
924 | if (!dev && (r->arp_flags & ATF_COM)) { | |
941666c2 | 925 | dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family, |
deffd777 | 926 | r->arp_ha.sa_data); |
43dc1701 PE |
927 | if (!dev) |
928 | return -ENODEV; | |
929 | } | |
930 | if (mask) { | |
51456b29 | 931 | if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1)) |
43dc1701 PE |
932 | return -ENOBUFS; |
933 | return 0; | |
934 | } | |
f8b33fdf | 935 | |
32e569b7 | 936 | return arp_req_set_proxy(net, dev, 1); |
43dc1701 PE |
937 | } |
938 | ||
32e569b7 | 939 | static int arp_req_set(struct net *net, struct arpreq *r, |
deffd777 | 940 | struct net_device *dev) |
1da177e4 | 941 | { |
43dc1701 | 942 | __be32 ip; |
1da177e4 LT |
943 | struct neighbour *neigh; |
944 | int err; | |
945 | ||
43dc1701 | 946 | if (r->arp_flags & ATF_PUBL) |
32e569b7 | 947 | return arp_req_set_public(net, r, dev); |
1da177e4 | 948 | |
43dc1701 | 949 | ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; |
1da177e4 LT |
950 | if (r->arp_flags & ATF_PERM) |
951 | r->arp_flags |= ATF_COM; | |
51456b29 | 952 | if (!dev) { |
78fbfd8a | 953 | struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); |
b23dd4fe DM |
954 | |
955 | if (IS_ERR(rt)) | |
956 | return PTR_ERR(rt); | |
d8d1f30b | 957 | dev = rt->dst.dev; |
1da177e4 LT |
958 | ip_rt_put(rt); |
959 | if (!dev) | |
960 | return -EINVAL; | |
961 | } | |
962 | switch (dev->type) { | |
40e4783e | 963 | #if IS_ENABLED(CONFIG_FDDI) |
1da177e4 LT |
964 | case ARPHRD_FDDI: |
965 | /* | |
966 | * According to RFC 1390, FDDI devices should accept ARP | |
967 | * hardware types of 1 (Ethernet). However, to be more | |
968 | * robust, we'll accept hardware types of either 1 (Ethernet) | |
969 | * or 6 (IEEE 802.2). | |
970 | */ | |
971 | if (r->arp_ha.sa_family != ARPHRD_FDDI && | |
972 | r->arp_ha.sa_family != ARPHRD_ETHER && | |
973 | r->arp_ha.sa_family != ARPHRD_IEEE802) | |
974 | return -EINVAL; | |
975 | break; | |
976 | #endif | |
977 | default: | |
978 | if (r->arp_ha.sa_family != dev->type) | |
979 | return -EINVAL; | |
980 | break; | |
981 | } | |
982 | ||
983 | neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev); | |
984 | err = PTR_ERR(neigh); | |
985 | if (!IS_ERR(neigh)) { | |
95c96174 | 986 | unsigned int state = NUD_STALE; |
1da177e4 LT |
987 | if (r->arp_flags & ATF_PERM) |
988 | state = NUD_PERMANENT; | |
deffd777 | 989 | err = neigh_update(neigh, (r->arp_flags & ATF_COM) ? |
e905a9ed | 990 | r->arp_ha.sa_data : NULL, state, |
deffd777 | 991 | NEIGH_UPDATE_F_OVERRIDE | |
1da177e4 LT |
992 | NEIGH_UPDATE_F_ADMIN); |
993 | neigh_release(neigh); | |
994 | } | |
995 | return err; | |
996 | } | |
997 | ||
95c96174 | 998 | static unsigned int arp_state_to_flags(struct neighbour *neigh) |
1da177e4 | 999 | { |
1da177e4 | 1000 | if (neigh->nud_state&NUD_PERMANENT) |
deffd777 | 1001 | return ATF_PERM | ATF_COM; |
1da177e4 | 1002 | else if (neigh->nud_state&NUD_VALID) |
deffd777 CG |
1003 | return ATF_COM; |
1004 | else | |
1005 | return 0; | |
1da177e4 LT |
1006 | } |
1007 | ||
1008 | /* | |
1009 | * Get an ARP cache entry. | |
1010 | */ | |
1011 | ||
1012 | static int arp_req_get(struct arpreq *r, struct net_device *dev) | |
1013 | { | |
ed9bad06 | 1014 | __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; |
1da177e4 LT |
1015 | struct neighbour *neigh; |
1016 | int err = -ENXIO; | |
1017 | ||
1018 | neigh = neigh_lookup(&arp_tbl, &ip, dev); | |
1019 | if (neigh) { | |
1020 | read_lock_bh(&neigh->lock); | |
1021 | memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); | |
1022 | r->arp_flags = arp_state_to_flags(neigh); | |
1023 | read_unlock_bh(&neigh->lock); | |
1024 | r->arp_ha.sa_family = dev->type; | |
1025 | strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev)); | |
1026 | neigh_release(neigh); | |
1027 | err = 0; | |
1028 | } | |
1029 | return err; | |
1030 | } | |
1031 | ||
7195cf72 | 1032 | static int arp_invalidate(struct net_device *dev, __be32 ip) |
545ecdc3 ML |
1033 | { |
1034 | struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); | |
1035 | int err = -ENXIO; | |
1036 | ||
1037 | if (neigh) { | |
1038 | if (neigh->nud_state & ~NUD_NOARP) | |
1039 | err = neigh_update(neigh, NULL, NUD_FAILED, | |
1040 | NEIGH_UPDATE_F_OVERRIDE| | |
1041 | NEIGH_UPDATE_F_ADMIN); | |
1042 | neigh_release(neigh); | |
1043 | } | |
1044 | ||
1045 | return err; | |
1046 | } | |
545ecdc3 | 1047 | |
32e569b7 PE |
1048 | static int arp_req_delete_public(struct net *net, struct arpreq *r, |
1049 | struct net_device *dev) | |
46479b43 PE |
1050 | { |
1051 | __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr; | |
1052 | __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr; | |
1053 | ||
1054 | if (mask == htonl(0xFFFFFFFF)) | |
2db82b53 | 1055 | return pneigh_delete(&arp_tbl, net, &ip, dev); |
46479b43 | 1056 | |
f8b33fdf PE |
1057 | if (mask) |
1058 | return -EINVAL; | |
1059 | ||
32e569b7 | 1060 | return arp_req_set_proxy(net, dev, 0); |
46479b43 PE |
1061 | } |
1062 | ||
32e569b7 | 1063 | static int arp_req_delete(struct net *net, struct arpreq *r, |
deffd777 | 1064 | struct net_device *dev) |
1da177e4 | 1065 | { |
46479b43 | 1066 | __be32 ip; |
1da177e4 | 1067 | |
46479b43 | 1068 | if (r->arp_flags & ATF_PUBL) |
32e569b7 | 1069 | return arp_req_delete_public(net, r, dev); |
1da177e4 | 1070 | |
46479b43 | 1071 | ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr; |
51456b29 | 1072 | if (!dev) { |
78fbfd8a | 1073 | struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0); |
b23dd4fe DM |
1074 | if (IS_ERR(rt)) |
1075 | return PTR_ERR(rt); | |
d8d1f30b | 1076 | dev = rt->dst.dev; |
1da177e4 LT |
1077 | ip_rt_put(rt); |
1078 | if (!dev) | |
1079 | return -EINVAL; | |
1080 | } | |
545ecdc3 | 1081 | return arp_invalidate(dev, ip); |
1da177e4 LT |
1082 | } |
1083 | ||
1084 | /* | |
1085 | * Handle an ARP layer I/O control request. | |
1086 | */ | |
1087 | ||
32e569b7 | 1088 | int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg) |
1da177e4 LT |
1089 | { |
1090 | int err; | |
1091 | struct arpreq r; | |
1092 | struct net_device *dev = NULL; | |
1093 | ||
1094 | switch (cmd) { | |
deffd777 CG |
1095 | case SIOCDARP: |
1096 | case SIOCSARP: | |
52e804c6 | 1097 | if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) |
deffd777 CG |
1098 | return -EPERM; |
1099 | case SIOCGARP: | |
1100 | err = copy_from_user(&r, arg, sizeof(struct arpreq)); | |
1101 | if (err) | |
1102 | return -EFAULT; | |
1103 | break; | |
1104 | default: | |
1105 | return -EINVAL; | |
1da177e4 LT |
1106 | } |
1107 | ||
1108 | if (r.arp_pa.sa_family != AF_INET) | |
1109 | return -EPFNOSUPPORT; | |
1110 | ||
1111 | if (!(r.arp_flags & ATF_PUBL) && | |
deffd777 | 1112 | (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB))) |
1da177e4 LT |
1113 | return -EINVAL; |
1114 | if (!(r.arp_flags & ATF_NETMASK)) | |
1115 | ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr = | |
1116 | htonl(0xFFFFFFFFUL); | |
c506653d | 1117 | rtnl_lock(); |
1da177e4 LT |
1118 | if (r.arp_dev[0]) { |
1119 | err = -ENODEV; | |
c506653d | 1120 | dev = __dev_get_by_name(net, r.arp_dev); |
51456b29 | 1121 | if (!dev) |
1da177e4 LT |
1122 | goto out; |
1123 | ||
1124 | /* Mmmm... It is wrong... ARPHRD_NETROM==0 */ | |
1125 | if (!r.arp_ha.sa_family) | |
1126 | r.arp_ha.sa_family = dev->type; | |
1127 | err = -EINVAL; | |
1128 | if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type) | |
1129 | goto out; | |
1130 | } else if (cmd == SIOCGARP) { | |
1131 | err = -ENODEV; | |
1132 | goto out; | |
1133 | } | |
1134 | ||
132adf54 | 1135 | switch (cmd) { |
1da177e4 | 1136 | case SIOCDARP: |
32e569b7 | 1137 | err = arp_req_delete(net, &r, dev); |
1da177e4 LT |
1138 | break; |
1139 | case SIOCSARP: | |
32e569b7 | 1140 | err = arp_req_set(net, &r, dev); |
1da177e4 LT |
1141 | break; |
1142 | case SIOCGARP: | |
1143 | err = arp_req_get(&r, dev); | |
1da177e4 LT |
1144 | break; |
1145 | } | |
1146 | out: | |
c506653d | 1147 | rtnl_unlock(); |
941666c2 ED |
1148 | if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r))) |
1149 | err = -EFAULT; | |
1da177e4 LT |
1150 | return err; |
1151 | } | |
1152 | ||
deffd777 CG |
1153 | static int arp_netdev_event(struct notifier_block *this, unsigned long event, |
1154 | void *ptr) | |
1da177e4 | 1155 | { |
351638e7 | 1156 | struct net_device *dev = netdev_notifier_info_to_dev(ptr); |
6c8b4e3f | 1157 | struct netdev_notifier_change_info *change_info; |
1da177e4 LT |
1158 | |
1159 | switch (event) { | |
1160 | case NETDEV_CHANGEADDR: | |
1161 | neigh_changeaddr(&arp_tbl, dev); | |
bafa6d9d | 1162 | rt_cache_flush(dev_net(dev)); |
1da177e4 | 1163 | break; |
6c8b4e3f TT |
1164 | case NETDEV_CHANGE: |
1165 | change_info = ptr; | |
1166 | if (change_info->flags_changed & IFF_NOARP) | |
1167 | neigh_changeaddr(&arp_tbl, dev); | |
1168 | break; | |
1da177e4 LT |
1169 | default: |
1170 | break; | |
1171 | } | |
1172 | ||
1173 | return NOTIFY_DONE; | |
1174 | } | |
1175 | ||
1176 | static struct notifier_block arp_netdev_notifier = { | |
1177 | .notifier_call = arp_netdev_event, | |
1178 | }; | |
1179 | ||
1180 | /* Note, that it is not on notifier chain. | |
1181 | It is necessary, that this routine was called after route cache will be | |
1182 | flushed. | |
1183 | */ | |
1184 | void arp_ifdown(struct net_device *dev) | |
1185 | { | |
1186 | neigh_ifdown(&arp_tbl, dev); | |
1187 | } | |
1188 | ||
1189 | ||
1190 | /* | |
1191 | * Called once on startup. | |
1192 | */ | |
1193 | ||
7546dd97 | 1194 | static struct packet_type arp_packet_type __read_mostly = { |
09640e63 | 1195 | .type = cpu_to_be16(ETH_P_ARP), |
1da177e4 LT |
1196 | .func = arp_rcv, |
1197 | }; | |
1198 | ||
1199 | static int arp_proc_init(void); | |
1200 | ||
1201 | void __init arp_init(void) | |
1202 | { | |
d7480fd3 | 1203 | neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl); |
1da177e4 LT |
1204 | |
1205 | dev_add_pack(&arp_packet_type); | |
1206 | arp_proc_init(); | |
1207 | #ifdef CONFIG_SYSCTL | |
73af614a | 1208 | neigh_sysctl_register(NULL, &arp_tbl.parms, NULL); |
1da177e4 LT |
1209 | #endif |
1210 | register_netdevice_notifier(&arp_netdev_notifier); | |
1211 | } | |
1212 | ||
1213 | #ifdef CONFIG_PROC_FS | |
40e4783e | 1214 | #if IS_ENABLED(CONFIG_AX25) |
1da177e4 LT |
1215 | |
1216 | /* ------------------------------------------------------------------------ */ | |
1217 | /* | |
1218 | * ax25 -> ASCII conversion | |
1219 | */ | |
1220 | static char *ax2asc2(ax25_address *a, char *buf) | |
1221 | { | |
1222 | char c, *s; | |
1223 | int n; | |
1224 | ||
1225 | for (n = 0, s = buf; n < 6; n++) { | |
1226 | c = (a->ax25_call[n] >> 1) & 0x7F; | |
1227 | ||
deffd777 CG |
1228 | if (c != ' ') |
1229 | *s++ = c; | |
1da177e4 | 1230 | } |
e905a9ed | 1231 | |
1da177e4 | 1232 | *s++ = '-'; |
deffd777 CG |
1233 | n = (a->ax25_call[6] >> 1) & 0x0F; |
1234 | if (n > 9) { | |
1da177e4 LT |
1235 | *s++ = '1'; |
1236 | n -= 10; | |
1237 | } | |
e905a9ed | 1238 | |
1da177e4 LT |
1239 | *s++ = n + '0'; |
1240 | *s++ = '\0'; | |
1241 | ||
1242 | if (*buf == '\0' || *buf == '-') | |
deffd777 | 1243 | return "*"; |
1da177e4 LT |
1244 | |
1245 | return buf; | |
1da177e4 LT |
1246 | } |
1247 | #endif /* CONFIG_AX25 */ | |
1248 | ||
1249 | #define HBUFFERLEN 30 | |
1250 | ||
1251 | static void arp_format_neigh_entry(struct seq_file *seq, | |
1252 | struct neighbour *n) | |
1253 | { | |
1254 | char hbuffer[HBUFFERLEN]; | |
1da177e4 LT |
1255 | int k, j; |
1256 | char tbuf[16]; | |
1257 | struct net_device *dev = n->dev; | |
1258 | int hatype = dev->type; | |
1259 | ||
1260 | read_lock(&n->lock); | |
1261 | /* Convert hardware address to XX:XX:XX:XX ... form. */ | |
40e4783e | 1262 | #if IS_ENABLED(CONFIG_AX25) |
1da177e4 LT |
1263 | if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM) |
1264 | ax2asc2((ax25_address *)n->ha, hbuffer); | |
1265 | else { | |
1266 | #endif | |
1267 | for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) { | |
51f82a2b DC |
1268 | hbuffer[k++] = hex_asc_hi(n->ha[j]); |
1269 | hbuffer[k++] = hex_asc_lo(n->ha[j]); | |
1da177e4 LT |
1270 | hbuffer[k++] = ':'; |
1271 | } | |
a3e8ee68 | 1272 | if (k != 0) |
1273 | --k; | |
1274 | hbuffer[k] = 0; | |
40e4783e | 1275 | #if IS_ENABLED(CONFIG_AX25) |
1da177e4 LT |
1276 | } |
1277 | #endif | |
673d57e7 | 1278 | sprintf(tbuf, "%pI4", n->primary_key); |
1da177e4 LT |
1279 | seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", |
1280 | tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name); | |
1281 | read_unlock(&n->lock); | |
1282 | } | |
1283 | ||
1284 | static void arp_format_pneigh_entry(struct seq_file *seq, | |
1285 | struct pneigh_entry *n) | |
1286 | { | |
1287 | struct net_device *dev = n->dev; | |
1288 | int hatype = dev ? dev->type : 0; | |
1289 | char tbuf[16]; | |
1290 | ||
673d57e7 | 1291 | sprintf(tbuf, "%pI4", n->key); |
1da177e4 LT |
1292 | seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n", |
1293 | tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00", | |
1294 | dev ? dev->name : "*"); | |
1295 | } | |
1296 | ||
1297 | static int arp_seq_show(struct seq_file *seq, void *v) | |
1298 | { | |
1299 | if (v == SEQ_START_TOKEN) { | |
1300 | seq_puts(seq, "IP address HW type Flags " | |
1301 | "HW address Mask Device\n"); | |
1302 | } else { | |
1303 | struct neigh_seq_state *state = seq->private; | |
1304 | ||
1305 | if (state->flags & NEIGH_SEQ_IS_PNEIGH) | |
1306 | arp_format_pneigh_entry(seq, v); | |
1307 | else | |
1308 | arp_format_neigh_entry(seq, v); | |
1309 | } | |
1310 | ||
1311 | return 0; | |
1312 | } | |
1313 | ||
1314 | static void *arp_seq_start(struct seq_file *seq, loff_t *pos) | |
1315 | { | |
1316 | /* Don't want to confuse "arp -a" w/ magic entries, | |
1317 | * so we tell the generic iterator to skip NUD_NOARP. | |
1318 | */ | |
1319 | return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP); | |
1320 | } | |
1321 | ||
1322 | /* ------------------------------------------------------------------------ */ | |
1323 | ||
f690808e | 1324 | static const struct seq_operations arp_seq_ops = { |
deffd777 CG |
1325 | .start = arp_seq_start, |
1326 | .next = neigh_seq_next, | |
1327 | .stop = neigh_seq_stop, | |
1328 | .show = arp_seq_show, | |
1da177e4 LT |
1329 | }; |
1330 | ||
1331 | static int arp_seq_open(struct inode *inode, struct file *file) | |
1332 | { | |
426b5303 EB |
1333 | return seq_open_net(inode, file, &arp_seq_ops, |
1334 | sizeof(struct neigh_seq_state)); | |
1da177e4 LT |
1335 | } |
1336 | ||
9a32144e | 1337 | static const struct file_operations arp_seq_fops = { |
1da177e4 LT |
1338 | .owner = THIS_MODULE, |
1339 | .open = arp_seq_open, | |
1340 | .read = seq_read, | |
1341 | .llseek = seq_lseek, | |
426b5303 | 1342 | .release = seq_release_net, |
1da177e4 LT |
1343 | }; |
1344 | ||
ffc31d3d DL |
1345 | |
1346 | static int __net_init arp_net_init(struct net *net) | |
1da177e4 | 1347 | { |
d4beaa66 | 1348 | if (!proc_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops)) |
1da177e4 LT |
1349 | return -ENOMEM; |
1350 | return 0; | |
1351 | } | |
1352 | ||
ffc31d3d DL |
1353 | static void __net_exit arp_net_exit(struct net *net) |
1354 | { | |
ece31ffd | 1355 | remove_proc_entry("arp", net->proc_net); |
ffc31d3d DL |
1356 | } |
1357 | ||
1358 | static struct pernet_operations arp_net_ops = { | |
1359 | .init = arp_net_init, | |
1360 | .exit = arp_net_exit, | |
1361 | }; | |
1362 | ||
1363 | static int __init arp_proc_init(void) | |
1364 | { | |
1365 | return register_pernet_subsys(&arp_net_ops); | |
1366 | } | |
1367 | ||
1da177e4 LT |
1368 | #else /* CONFIG_PROC_FS */ |
1369 | ||
1370 | static int __init arp_proc_init(void) | |
1371 | { | |
1372 | return 0; | |
1373 | } | |
1374 | ||
1375 | #endif /* CONFIG_PROC_FS */ |