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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * NET3: Implementation of the ICMP protocol layer. | |
3 | * | |
113aa838 | 4 | * Alan Cox, <alan@lxorguk.ukuu.org.uk> |
1da177e4 | 5 | * |
1da177e4 LT |
6 | * This program is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * Some of the function names and the icmp unreach table for this | |
12 | * module were derived from [icmp.c 1.0.11 06/02/93] by | |
13 | * Ross Biro, Fred N. van Kempen, Mark Evans, Alan Cox, Gerhard Koerting. | |
14 | * Other than that this module is a complete rewrite. | |
15 | * | |
16 | * Fixes: | |
17 | * Clemens Fruhwirth : introduce global icmp rate limiting | |
18 | * with icmp type masking ability instead | |
19 | * of broken per type icmp timeouts. | |
20 | * Mike Shaver : RFC1122 checks. | |
21 | * Alan Cox : Multicast ping reply as self. | |
22 | * Alan Cox : Fix atomicity lockup in ip_build_xmit | |
23 | * call. | |
24 | * Alan Cox : Added 216,128 byte paths to the MTU | |
25 | * code. | |
26 | * Martin Mares : RFC1812 checks. | |
27 | * Martin Mares : Can be configured to follow redirects | |
28 | * if acting as a router _without_ a | |
29 | * routing protocol (RFC 1812). | |
30 | * Martin Mares : Echo requests may be configured to | |
31 | * be ignored (RFC 1812). | |
32 | * Martin Mares : Limitation of ICMP error message | |
33 | * transmit rate (RFC 1812). | |
34 | * Martin Mares : TOS and Precedence set correctly | |
35 | * (RFC 1812). | |
36 | * Martin Mares : Now copying as much data from the | |
37 | * original packet as we can without | |
38 | * exceeding 576 bytes (RFC 1812). | |
39 | * Willy Konynenberg : Transparent proxying support. | |
40 | * Keith Owens : RFC1191 correction for 4.2BSD based | |
41 | * path MTU bug. | |
42 | * Thomas Quinot : ICMP Dest Unreach codes up to 15 are | |
43 | * valid (RFC 1812). | |
44 | * Andi Kleen : Check all packet lengths properly | |
45 | * and moved all kfree_skb() up to | |
46 | * icmp_rcv. | |
47 | * Andi Kleen : Move the rate limit bookkeeping | |
48 | * into the dest entry and use a token | |
49 | * bucket filter (thanks to ANK). Make | |
50 | * the rates sysctl configurable. | |
51 | * Yu Tianli : Fixed two ugly bugs in icmp_send | |
52 | * - IP option length was accounted wrongly | |
53 | * - ICMP header length was not accounted | |
54 | * at all. | |
55 | * Tristan Greaves : Added sysctl option to ignore bogus | |
56 | * broadcast responses from broken routers. | |
57 | * | |
58 | * To Fix: | |
59 | * | |
60 | * - Should use skb_pull() instead of all the manual checking. | |
61 | * This would also greatly simply some upper layer error handlers. --AK | |
62 | * | |
63 | */ | |
64 | ||
afd46503 JP |
65 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
66 | ||
1da177e4 LT |
67 | #include <linux/module.h> |
68 | #include <linux/types.h> | |
69 | #include <linux/jiffies.h> | |
70 | #include <linux/kernel.h> | |
71 | #include <linux/fcntl.h> | |
72 | #include <linux/socket.h> | |
73 | #include <linux/in.h> | |
74 | #include <linux/inet.h> | |
14c85021 | 75 | #include <linux/inetdevice.h> |
1da177e4 LT |
76 | #include <linux/netdevice.h> |
77 | #include <linux/string.h> | |
78 | #include <linux/netfilter_ipv4.h> | |
5a0e3ad6 | 79 | #include <linux/slab.h> |
1da177e4 LT |
80 | #include <net/snmp.h> |
81 | #include <net/ip.h> | |
82 | #include <net/route.h> | |
83 | #include <net/protocol.h> | |
84 | #include <net/icmp.h> | |
85 | #include <net/tcp.h> | |
86 | #include <net/udp.h> | |
87 | #include <net/raw.h> | |
c319b4d7 | 88 | #include <net/ping.h> |
1da177e4 LT |
89 | #include <linux/skbuff.h> |
90 | #include <net/sock.h> | |
91 | #include <linux/errno.h> | |
92 | #include <linux/timer.h> | |
93 | #include <linux/init.h> | |
1da177e4 LT |
94 | #include <asm/uaccess.h> |
95 | #include <net/checksum.h> | |
8b7817f3 | 96 | #include <net/xfrm.h> |
c1e9894d | 97 | #include <net/inet_common.h> |
35ebf65e | 98 | #include <net/ip_fib.h> |
1da177e4 LT |
99 | |
100 | /* | |
101 | * Build xmit assembly blocks | |
102 | */ | |
103 | ||
104 | struct icmp_bxm { | |
105 | struct sk_buff *skb; | |
106 | int offset; | |
107 | int data_len; | |
108 | ||
109 | struct { | |
110 | struct icmphdr icmph; | |
b03d73e3 | 111 | __be32 times[3]; |
1da177e4 LT |
112 | } data; |
113 | int head_len; | |
f6d8bd05 | 114 | struct ip_options_data replyopts; |
1da177e4 LT |
115 | }; |
116 | ||
1da177e4 LT |
117 | /* An array of errno for error messages from dest unreach. */ |
118 | /* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */ | |
119 | ||
e754834e | 120 | const struct icmp_err icmp_err_convert[] = { |
1da177e4 LT |
121 | { |
122 | .errno = ENETUNREACH, /* ICMP_NET_UNREACH */ | |
123 | .fatal = 0, | |
124 | }, | |
125 | { | |
126 | .errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */ | |
127 | .fatal = 0, | |
128 | }, | |
129 | { | |
130 | .errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */, | |
131 | .fatal = 1, | |
132 | }, | |
133 | { | |
134 | .errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */ | |
135 | .fatal = 1, | |
136 | }, | |
137 | { | |
138 | .errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */ | |
139 | .fatal = 0, | |
140 | }, | |
141 | { | |
142 | .errno = EOPNOTSUPP, /* ICMP_SR_FAILED */ | |
143 | .fatal = 0, | |
144 | }, | |
145 | { | |
146 | .errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */ | |
147 | .fatal = 1, | |
148 | }, | |
149 | { | |
150 | .errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */ | |
151 | .fatal = 1, | |
152 | }, | |
153 | { | |
154 | .errno = ENONET, /* ICMP_HOST_ISOLATED */ | |
155 | .fatal = 1, | |
156 | }, | |
157 | { | |
158 | .errno = ENETUNREACH, /* ICMP_NET_ANO */ | |
159 | .fatal = 1, | |
160 | }, | |
161 | { | |
162 | .errno = EHOSTUNREACH, /* ICMP_HOST_ANO */ | |
163 | .fatal = 1, | |
164 | }, | |
165 | { | |
166 | .errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */ | |
167 | .fatal = 0, | |
168 | }, | |
169 | { | |
170 | .errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */ | |
171 | .fatal = 0, | |
172 | }, | |
173 | { | |
174 | .errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */ | |
175 | .fatal = 1, | |
176 | }, | |
177 | { | |
178 | .errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */ | |
179 | .fatal = 1, | |
180 | }, | |
181 | { | |
182 | .errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */ | |
183 | .fatal = 1, | |
184 | }, | |
185 | }; | |
4bc2f18b | 186 | EXPORT_SYMBOL(icmp_err_convert); |
1da177e4 | 187 | |
1da177e4 LT |
188 | /* |
189 | * ICMP control array. This specifies what to do with each ICMP. | |
190 | */ | |
191 | ||
192 | struct icmp_control { | |
e3e32170 | 193 | bool (*handler)(struct sk_buff *skb); |
1da177e4 LT |
194 | short error; /* This ICMP is classed as an error message */ |
195 | }; | |
196 | ||
9b5b5cff | 197 | static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1]; |
1da177e4 LT |
198 | |
199 | /* | |
200 | * The ICMP socket(s). This is the most convenient way to flow control | |
201 | * our ICMP output as well as maintain a clean interface throughout | |
202 | * all layers. All Socketless IP sends will soon be gone. | |
203 | * | |
204 | * On SMP we have one ICMP socket per-cpu. | |
205 | */ | |
4a6ad7a1 DL |
206 | static struct sock *icmp_sk(struct net *net) |
207 | { | |
349c9e3c | 208 | return *this_cpu_ptr(net->ipv4.icmp_sk); |
4a6ad7a1 | 209 | } |
1da177e4 | 210 | |
fdc0bde9 | 211 | static inline struct sock *icmp_xmit_lock(struct net *net) |
1da177e4 | 212 | { |
fdc0bde9 DL |
213 | struct sock *sk; |
214 | ||
1da177e4 LT |
215 | local_bh_disable(); |
216 | ||
fdc0bde9 DL |
217 | sk = icmp_sk(net); |
218 | ||
405666db | 219 | if (unlikely(!spin_trylock(&sk->sk_lock.slock))) { |
1da177e4 LT |
220 | /* This can happen if the output path signals a |
221 | * dst_link_failure() for an outgoing ICMP packet. | |
222 | */ | |
223 | local_bh_enable(); | |
fdc0bde9 | 224 | return NULL; |
1da177e4 | 225 | } |
fdc0bde9 | 226 | return sk; |
1da177e4 LT |
227 | } |
228 | ||
405666db | 229 | static inline void icmp_xmit_unlock(struct sock *sk) |
1da177e4 | 230 | { |
405666db | 231 | spin_unlock_bh(&sk->sk_lock.slock); |
1da177e4 LT |
232 | } |
233 | ||
4cdf507d ED |
234 | int sysctl_icmp_msgs_per_sec __read_mostly = 1000; |
235 | int sysctl_icmp_msgs_burst __read_mostly = 50; | |
236 | ||
237 | static struct { | |
238 | spinlock_t lock; | |
239 | u32 credit; | |
240 | u32 stamp; | |
241 | } icmp_global = { | |
242 | .lock = __SPIN_LOCK_UNLOCKED(icmp_global.lock), | |
243 | }; | |
244 | ||
245 | /** | |
246 | * icmp_global_allow - Are we allowed to send one more ICMP message ? | |
247 | * | |
248 | * Uses a token bucket to limit our ICMP messages to sysctl_icmp_msgs_per_sec. | |
249 | * Returns false if we reached the limit and can not send another packet. | |
250 | * Note: called with BH disabled | |
251 | */ | |
252 | bool icmp_global_allow(void) | |
253 | { | |
254 | u32 credit, delta, incr = 0, now = (u32)jiffies; | |
255 | bool rc = false; | |
256 | ||
257 | /* Check if token bucket is empty and cannot be refilled | |
258 | * without taking the spinlock. | |
259 | */ | |
260 | if (!icmp_global.credit) { | |
261 | delta = min_t(u32, now - icmp_global.stamp, HZ); | |
262 | if (delta < HZ / 50) | |
263 | return false; | |
264 | } | |
265 | ||
266 | spin_lock(&icmp_global.lock); | |
267 | delta = min_t(u32, now - icmp_global.stamp, HZ); | |
268 | if (delta >= HZ / 50) { | |
269 | incr = sysctl_icmp_msgs_per_sec * delta / HZ ; | |
270 | if (incr) | |
271 | icmp_global.stamp = now; | |
272 | } | |
273 | credit = min_t(u32, icmp_global.credit + incr, sysctl_icmp_msgs_burst); | |
274 | if (credit) { | |
275 | credit--; | |
276 | rc = true; | |
277 | } | |
278 | icmp_global.credit = credit; | |
279 | spin_unlock(&icmp_global.lock); | |
280 | return rc; | |
281 | } | |
282 | EXPORT_SYMBOL(icmp_global_allow); | |
283 | ||
1da177e4 LT |
284 | /* |
285 | * Send an ICMP frame. | |
286 | */ | |
287 | ||
4cdf507d ED |
288 | static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt, |
289 | struct flowi4 *fl4, int type, int code) | |
1da177e4 | 290 | { |
d8d1f30b | 291 | struct dst_entry *dst = &rt->dst; |
92d86829 | 292 | bool rc = true; |
1da177e4 LT |
293 | |
294 | if (type > NR_ICMP_TYPES) | |
295 | goto out; | |
296 | ||
297 | /* Don't limit PMTU discovery. */ | |
298 | if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) | |
299 | goto out; | |
300 | ||
301 | /* No rate limit on loopback */ | |
302 | if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) | |
e905a9ed | 303 | goto out; |
1da177e4 LT |
304 | |
305 | /* Limit if icmp type is enabled in ratemask. */ | |
4cdf507d ED |
306 | if (!((1 << type) & net->ipv4.sysctl_icmp_ratemask)) |
307 | goto out; | |
308 | ||
309 | rc = false; | |
310 | if (icmp_global_allow()) { | |
311 | struct inet_peer *peer; | |
312 | ||
313 | peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, 1); | |
fbfe95a4 | 314 | rc = inet_peer_xrlim_allow(peer, |
92d86829 | 315 | net->ipv4.sysctl_icmp_ratelimit); |
e1a67642 NC |
316 | if (peer) |
317 | inet_putpeer(peer); | |
92d86829 | 318 | } |
1da177e4 LT |
319 | out: |
320 | return rc; | |
321 | } | |
322 | ||
323 | /* | |
324 | * Maintain the counters used in the SNMP statistics for outgoing ICMP | |
325 | */ | |
0388b004 | 326 | void icmp_out_count(struct net *net, unsigned char type) |
1da177e4 | 327 | { |
903fc196 | 328 | ICMPMSGOUT_INC_STATS(net, type); |
75c939bb | 329 | ICMP_INC_STATS(net, ICMP_MIB_OUTMSGS); |
1da177e4 LT |
330 | } |
331 | ||
332 | /* | |
333 | * Checksum each fragment, and on the first include the headers and final | |
334 | * checksum. | |
335 | */ | |
336 | static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd, | |
337 | struct sk_buff *skb) | |
338 | { | |
339 | struct icmp_bxm *icmp_param = (struct icmp_bxm *)from; | |
5f92a738 | 340 | __wsum csum; |
1da177e4 LT |
341 | |
342 | csum = skb_copy_and_csum_bits(icmp_param->skb, | |
343 | icmp_param->offset + offset, | |
344 | to, len, 0); | |
345 | ||
346 | skb->csum = csum_block_add(skb->csum, csum, odd); | |
347 | if (icmp_pointers[icmp_param->data.icmph.type].error) | |
348 | nf_ct_attach(skb, icmp_param->skb); | |
349 | return 0; | |
350 | } | |
351 | ||
352 | static void icmp_push_reply(struct icmp_bxm *icmp_param, | |
77968b78 | 353 | struct flowi4 *fl4, |
2e77d89b | 354 | struct ipcm_cookie *ipc, struct rtable **rt) |
1da177e4 | 355 | { |
1e3cf683 | 356 | struct sock *sk; |
1da177e4 LT |
357 | struct sk_buff *skb; |
358 | ||
d8d1f30b | 359 | sk = icmp_sk(dev_net((*rt)->dst.dev)); |
f5fca608 | 360 | if (ip_append_data(sk, fl4, icmp_glue_bits, icmp_param, |
e905a9ed YH |
361 | icmp_param->data_len+icmp_param->head_len, |
362 | icmp_param->head_len, | |
1f8438a8 ED |
363 | ipc, rt, MSG_DONTWAIT) < 0) { |
364 | ICMP_INC_STATS_BH(sock_net(sk), ICMP_MIB_OUTERRORS); | |
1e3cf683 | 365 | ip_flush_pending_frames(sk); |
1f8438a8 | 366 | } else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) { |
88c7664f | 367 | struct icmphdr *icmph = icmp_hdr(skb); |
d3bc23e7 | 368 | __wsum csum = 0; |
1da177e4 LT |
369 | struct sk_buff *skb1; |
370 | ||
1e3cf683 | 371 | skb_queue_walk(&sk->sk_write_queue, skb1) { |
1da177e4 LT |
372 | csum = csum_add(csum, skb1->csum); |
373 | } | |
374 | csum = csum_partial_copy_nocheck((void *)&icmp_param->data, | |
375 | (char *)icmph, | |
376 | icmp_param->head_len, csum); | |
377 | icmph->checksum = csum_fold(csum); | |
378 | skb->ip_summed = CHECKSUM_NONE; | |
77968b78 | 379 | ip_push_pending_frames(sk, fl4); |
1da177e4 LT |
380 | } |
381 | } | |
382 | ||
383 | /* | |
384 | * Driving logic for building and sending ICMP messages. | |
385 | */ | |
386 | ||
387 | static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) | |
388 | { | |
1da177e4 | 389 | struct ipcm_cookie ipc; |
511c3f92 | 390 | struct rtable *rt = skb_rtable(skb); |
d8d1f30b | 391 | struct net *net = dev_net(rt->dst.dev); |
77968b78 | 392 | struct flowi4 fl4; |
fdc0bde9 DL |
393 | struct sock *sk; |
394 | struct inet_sock *inet; | |
35ebf65e | 395 | __be32 daddr, saddr; |
e110861f | 396 | u32 mark = IP4_REPLY_MARK(net, skb->mark); |
1da177e4 | 397 | |
f6d8bd05 | 398 | if (ip_options_echo(&icmp_param->replyopts.opt.opt, skb)) |
f00c401b | 399 | return; |
1da177e4 | 400 | |
fdc0bde9 | 401 | sk = icmp_xmit_lock(net); |
51456b29 | 402 | if (!sk) |
1da177e4 | 403 | return; |
fdc0bde9 | 404 | inet = inet_sk(sk); |
1da177e4 LT |
405 | |
406 | icmp_param->data.icmph.checksum = 0; | |
1da177e4 | 407 | |
eddc9ec5 | 408 | inet->tos = ip_hdr(skb)->tos; |
e110861f | 409 | sk->sk_mark = mark; |
9f6abb5f | 410 | daddr = ipc.addr = ip_hdr(skb)->saddr; |
35ebf65e | 411 | saddr = fib_compute_spec_dst(skb); |
1da177e4 | 412 | ipc.opt = NULL; |
2244d07b | 413 | ipc.tx_flags = 0; |
aa661581 FF |
414 | ipc.ttl = 0; |
415 | ipc.tos = -1; | |
416 | ||
f6d8bd05 ED |
417 | if (icmp_param->replyopts.opt.opt.optlen) { |
418 | ipc.opt = &icmp_param->replyopts.opt; | |
419 | if (ipc.opt->opt.srr) | |
420 | daddr = icmp_param->replyopts.opt.opt.faddr; | |
1da177e4 | 421 | } |
77968b78 DM |
422 | memset(&fl4, 0, sizeof(fl4)); |
423 | fl4.daddr = daddr; | |
35ebf65e | 424 | fl4.saddr = saddr; |
e110861f | 425 | fl4.flowi4_mark = mark; |
77968b78 DM |
426 | fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos); |
427 | fl4.flowi4_proto = IPPROTO_ICMP; | |
428 | security_skb_classify_flow(skb, flowi4_to_flowi(&fl4)); | |
429 | rt = ip_route_output_key(net, &fl4); | |
430 | if (IS_ERR(rt)) | |
431 | goto out_unlock; | |
a48eff12 | 432 | if (icmpv4_xrlim_allow(net, rt, &fl4, icmp_param->data.icmph.type, |
1da177e4 | 433 | icmp_param->data.icmph.code)) |
77968b78 | 434 | icmp_push_reply(icmp_param, &fl4, &ipc, &rt); |
1da177e4 LT |
435 | ip_rt_put(rt); |
436 | out_unlock: | |
405666db | 437 | icmp_xmit_unlock(sk); |
1da177e4 LT |
438 | } |
439 | ||
77968b78 DM |
440 | static struct rtable *icmp_route_lookup(struct net *net, |
441 | struct flowi4 *fl4, | |
442 | struct sk_buff *skb_in, | |
b71d1d42 | 443 | const struct iphdr *iph, |
e110861f | 444 | __be32 saddr, u8 tos, u32 mark, |
f6d460cf DM |
445 | int type, int code, |
446 | struct icmp_bxm *param) | |
447 | { | |
f6d460cf | 448 | struct rtable *rt, *rt2; |
415b3334 | 449 | struct flowi4 fl4_dec; |
f6d460cf DM |
450 | int err; |
451 | ||
77968b78 DM |
452 | memset(fl4, 0, sizeof(*fl4)); |
453 | fl4->daddr = (param->replyopts.opt.opt.srr ? | |
454 | param->replyopts.opt.opt.faddr : iph->saddr); | |
455 | fl4->saddr = saddr; | |
e110861f | 456 | fl4->flowi4_mark = mark; |
77968b78 DM |
457 | fl4->flowi4_tos = RT_TOS(tos); |
458 | fl4->flowi4_proto = IPPROTO_ICMP; | |
459 | fl4->fl4_icmp_type = type; | |
460 | fl4->fl4_icmp_code = code; | |
461 | security_skb_classify_flow(skb_in, flowi4_to_flowi(fl4)); | |
462 | rt = __ip_route_output_key(net, fl4); | |
b23dd4fe DM |
463 | if (IS_ERR(rt)) |
464 | return rt; | |
f6d460cf DM |
465 | |
466 | /* No need to clone since we're just using its address. */ | |
467 | rt2 = rt; | |
468 | ||
9d6ec938 | 469 | rt = (struct rtable *) xfrm_lookup(net, &rt->dst, |
77968b78 | 470 | flowi4_to_flowi(fl4), NULL, 0); |
452edd59 | 471 | if (!IS_ERR(rt)) { |
f6d460cf DM |
472 | if (rt != rt2) |
473 | return rt; | |
452edd59 | 474 | } else if (PTR_ERR(rt) == -EPERM) { |
f6d460cf | 475 | rt = NULL; |
452edd59 DM |
476 | } else |
477 | return rt; | |
f6d460cf | 478 | |
415b3334 | 479 | err = xfrm_decode_session_reverse(skb_in, flowi4_to_flowi(&fl4_dec), AF_INET); |
f6d460cf DM |
480 | if (err) |
481 | goto relookup_failed; | |
482 | ||
415b3334 DM |
483 | if (inet_addr_type(net, fl4_dec.saddr) == RTN_LOCAL) { |
484 | rt2 = __ip_route_output_key(net, &fl4_dec); | |
b23dd4fe DM |
485 | if (IS_ERR(rt2)) |
486 | err = PTR_ERR(rt2); | |
f6d460cf | 487 | } else { |
9d6ec938 | 488 | struct flowi4 fl4_2 = {}; |
f6d460cf DM |
489 | unsigned long orefdst; |
490 | ||
415b3334 | 491 | fl4_2.daddr = fl4_dec.saddr; |
9d6ec938 | 492 | rt2 = ip_route_output_key(net, &fl4_2); |
b23dd4fe DM |
493 | if (IS_ERR(rt2)) { |
494 | err = PTR_ERR(rt2); | |
f6d460cf | 495 | goto relookup_failed; |
b23dd4fe | 496 | } |
f6d460cf DM |
497 | /* Ugh! */ |
498 | orefdst = skb_in->_skb_refdst; /* save old refdst */ | |
415b3334 | 499 | err = ip_route_input(skb_in, fl4_dec.daddr, fl4_dec.saddr, |
f6d460cf DM |
500 | RT_TOS(tos), rt2->dst.dev); |
501 | ||
502 | dst_release(&rt2->dst); | |
503 | rt2 = skb_rtable(skb_in); | |
504 | skb_in->_skb_refdst = orefdst; /* restore old refdst */ | |
505 | } | |
506 | ||
507 | if (err) | |
508 | goto relookup_failed; | |
509 | ||
9d6ec938 | 510 | rt2 = (struct rtable *) xfrm_lookup(net, &rt2->dst, |
415b3334 | 511 | flowi4_to_flowi(&fl4_dec), NULL, |
9d6ec938 | 512 | XFRM_LOOKUP_ICMP); |
452edd59 | 513 | if (!IS_ERR(rt2)) { |
f6d460cf | 514 | dst_release(&rt->dst); |
415b3334 | 515 | memcpy(fl4, &fl4_dec, sizeof(*fl4)); |
f6d460cf | 516 | rt = rt2; |
452edd59 DM |
517 | } else if (PTR_ERR(rt2) == -EPERM) { |
518 | if (rt) | |
519 | dst_release(&rt->dst); | |
520 | return rt2; | |
521 | } else { | |
522 | err = PTR_ERR(rt2); | |
523 | goto relookup_failed; | |
f6d460cf | 524 | } |
f6d460cf DM |
525 | return rt; |
526 | ||
527 | relookup_failed: | |
528 | if (rt) | |
529 | return rt; | |
530 | return ERR_PTR(err); | |
531 | } | |
1da177e4 LT |
532 | |
533 | /* | |
534 | * Send an ICMP message in response to a situation | |
535 | * | |
536 | * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. | |
537 | * MAY send more (we do). | |
538 | * MUST NOT change this header information. | |
539 | * MUST NOT reply to a multicast/broadcast IP address. | |
540 | * MUST NOT reply to a multicast/broadcast MAC address. | |
541 | * MUST reply to only the first fragment. | |
542 | */ | |
543 | ||
e4883014 | 544 | void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info) |
1da177e4 LT |
545 | { |
546 | struct iphdr *iph; | |
547 | int room; | |
9a99d4a5 | 548 | struct icmp_bxm *icmp_param; |
511c3f92 | 549 | struct rtable *rt = skb_rtable(skb_in); |
1da177e4 | 550 | struct ipcm_cookie ipc; |
77968b78 | 551 | struct flowi4 fl4; |
a61ced5d | 552 | __be32 saddr; |
1da177e4 | 553 | u8 tos; |
e110861f | 554 | u32 mark; |
dde1bc0e | 555 | struct net *net; |
4a6ad7a1 | 556 | struct sock *sk; |
1da177e4 LT |
557 | |
558 | if (!rt) | |
559 | goto out; | |
d8d1f30b | 560 | net = dev_net(rt->dst.dev); |
1da177e4 LT |
561 | |
562 | /* | |
563 | * Find the original header. It is expected to be valid, of course. | |
564 | * Check this, icmp_send is called from the most obscure devices | |
565 | * sometimes. | |
566 | */ | |
eddc9ec5 | 567 | iph = ip_hdr(skb_in); |
1da177e4 | 568 | |
27a884dc | 569 | if ((u8 *)iph < skb_in->head || |
f7c0c2ae SH |
570 | (skb_network_header(skb_in) + sizeof(*iph)) > |
571 | skb_tail_pointer(skb_in)) | |
1da177e4 LT |
572 | goto out; |
573 | ||
574 | /* | |
575 | * No replies to physical multicast/broadcast | |
576 | */ | |
577 | if (skb_in->pkt_type != PACKET_HOST) | |
578 | goto out; | |
579 | ||
580 | /* | |
581 | * Now check at the protocol level | |
582 | */ | |
583 | if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) | |
584 | goto out; | |
585 | ||
586 | /* | |
587 | * Only reply to fragment 0. We byte re-order the constant | |
588 | * mask for efficiency. | |
589 | */ | |
590 | if (iph->frag_off & htons(IP_OFFSET)) | |
591 | goto out; | |
592 | ||
593 | /* | |
594 | * If we send an ICMP error to an ICMP error a mess would result.. | |
595 | */ | |
596 | if (icmp_pointers[type].error) { | |
597 | /* | |
598 | * We are an error, check if we are replying to an | |
599 | * ICMP error | |
600 | */ | |
601 | if (iph->protocol == IPPROTO_ICMP) { | |
602 | u8 _inner_type, *itp; | |
603 | ||
604 | itp = skb_header_pointer(skb_in, | |
d56f90a7 | 605 | skb_network_header(skb_in) + |
1da177e4 LT |
606 | (iph->ihl << 2) + |
607 | offsetof(struct icmphdr, | |
608 | type) - | |
609 | skb_in->data, | |
610 | sizeof(_inner_type), | |
611 | &_inner_type); | |
51456b29 | 612 | if (!itp) |
1da177e4 LT |
613 | goto out; |
614 | ||
615 | /* | |
616 | * Assume any unknown ICMP type is an error. This | |
617 | * isn't specified by the RFC, but think about it.. | |
618 | */ | |
619 | if (*itp > NR_ICMP_TYPES || | |
620 | icmp_pointers[*itp].error) | |
621 | goto out; | |
622 | } | |
623 | } | |
624 | ||
9a99d4a5 CW |
625 | icmp_param = kmalloc(sizeof(*icmp_param), GFP_ATOMIC); |
626 | if (!icmp_param) | |
627 | return; | |
628 | ||
fdc0bde9 | 629 | sk = icmp_xmit_lock(net); |
51456b29 | 630 | if (!sk) |
9a99d4a5 | 631 | goto out_free; |
1da177e4 LT |
632 | |
633 | /* | |
634 | * Construct source address and options. | |
635 | */ | |
636 | ||
637 | saddr = iph->daddr; | |
1c2fb7f9 | 638 | if (!(rt->rt_flags & RTCF_LOCAL)) { |
6e1d9103 PM |
639 | struct net_device *dev = NULL; |
640 | ||
685c7944 | 641 | rcu_read_lock(); |
c7537967 DM |
642 | if (rt_is_input_route(rt) && |
643 | net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr) | |
92101b3b | 644 | dev = dev_get_by_index_rcu(net, inet_iif(skb_in)); |
6e1d9103 | 645 | |
685c7944 | 646 | if (dev) |
6e1d9103 | 647 | saddr = inet_select_addr(dev, 0, RT_SCOPE_LINK); |
685c7944 | 648 | else |
1c2fb7f9 | 649 | saddr = 0; |
685c7944 | 650 | rcu_read_unlock(); |
1c2fb7f9 | 651 | } |
1da177e4 LT |
652 | |
653 | tos = icmp_pointers[type].error ? ((iph->tos & IPTOS_TOS_MASK) | | |
654 | IPTOS_PREC_INTERNETCONTROL) : | |
655 | iph->tos; | |
e110861f | 656 | mark = IP4_REPLY_MARK(net, skb_in->mark); |
1da177e4 | 657 | |
9a99d4a5 | 658 | if (ip_options_echo(&icmp_param->replyopts.opt.opt, skb_in)) |
fa60cf7f | 659 | goto out_unlock; |
1da177e4 LT |
660 | |
661 | ||
662 | /* | |
663 | * Prepare data for ICMP header. | |
664 | */ | |
665 | ||
9a99d4a5 CW |
666 | icmp_param->data.icmph.type = type; |
667 | icmp_param->data.icmph.code = code; | |
668 | icmp_param->data.icmph.un.gateway = info; | |
669 | icmp_param->data.icmph.checksum = 0; | |
670 | icmp_param->skb = skb_in; | |
671 | icmp_param->offset = skb_network_offset(skb_in); | |
405666db | 672 | inet_sk(sk)->tos = tos; |
e110861f | 673 | sk->sk_mark = mark; |
1da177e4 | 674 | ipc.addr = iph->saddr; |
9a99d4a5 | 675 | ipc.opt = &icmp_param->replyopts.opt; |
2244d07b | 676 | ipc.tx_flags = 0; |
aa661581 FF |
677 | ipc.ttl = 0; |
678 | ipc.tos = -1; | |
1da177e4 | 679 | |
e110861f | 680 | rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr, tos, mark, |
9a99d4a5 | 681 | type, code, icmp_param); |
f6d460cf DM |
682 | if (IS_ERR(rt)) |
683 | goto out_unlock; | |
1da177e4 | 684 | |
a48eff12 | 685 | if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code)) |
1da177e4 LT |
686 | goto ende; |
687 | ||
688 | /* RFC says return as much as we can without exceeding 576 bytes. */ | |
689 | ||
d8d1f30b | 690 | room = dst_mtu(&rt->dst); |
1da177e4 LT |
691 | if (room > 576) |
692 | room = 576; | |
9a99d4a5 | 693 | room -= sizeof(struct iphdr) + icmp_param->replyopts.opt.opt.optlen; |
1da177e4 LT |
694 | room -= sizeof(struct icmphdr); |
695 | ||
9a99d4a5 CW |
696 | icmp_param->data_len = skb_in->len - icmp_param->offset; |
697 | if (icmp_param->data_len > room) | |
698 | icmp_param->data_len = room; | |
699 | icmp_param->head_len = sizeof(struct icmphdr); | |
1da177e4 | 700 | |
9a99d4a5 | 701 | icmp_push_reply(icmp_param, &fl4, &ipc, &rt); |
1da177e4 LT |
702 | ende: |
703 | ip_rt_put(rt); | |
704 | out_unlock: | |
405666db | 705 | icmp_xmit_unlock(sk); |
9a99d4a5 CW |
706 | out_free: |
707 | kfree(icmp_param); | |
1da177e4 LT |
708 | out:; |
709 | } | |
4bc2f18b | 710 | EXPORT_SYMBOL(icmp_send); |
1da177e4 LT |
711 | |
712 | ||
1de9243b DM |
713 | static void icmp_socket_deliver(struct sk_buff *skb, u32 info) |
714 | { | |
715 | const struct iphdr *iph = (const struct iphdr *) skb->data; | |
716 | const struct net_protocol *ipprot; | |
717 | int protocol = iph->protocol; | |
718 | ||
f0a70e90 DM |
719 | /* Checkin full IP header plus 8 bytes of protocol to |
720 | * avoid additional coding at protocol handlers. | |
721 | */ | |
7304fe46 DJ |
722 | if (!pskb_may_pull(skb, iph->ihl * 4 + 8)) { |
723 | ICMP_INC_STATS_BH(dev_net(skb->dev), ICMP_MIB_INERRORS); | |
f0a70e90 | 724 | return; |
7304fe46 | 725 | } |
f0a70e90 | 726 | |
1de9243b DM |
727 | raw_icmp_error(skb, protocol, info); |
728 | ||
1de9243b DM |
729 | ipprot = rcu_dereference(inet_protos[protocol]); |
730 | if (ipprot && ipprot->err_handler) | |
731 | ipprot->err_handler(skb, info); | |
1de9243b DM |
732 | } |
733 | ||
8ed1dc44 HFS |
734 | static bool icmp_tag_validation(int proto) |
735 | { | |
736 | bool ok; | |
737 | ||
738 | rcu_read_lock(); | |
739 | ok = rcu_dereference(inet_protos[proto])->icmp_strict_tag_validation; | |
740 | rcu_read_unlock(); | |
741 | return ok; | |
742 | } | |
743 | ||
1da177e4 | 744 | /* |
08578d8d RR |
745 | * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEED, ICMP_QUENCH, and |
746 | * ICMP_PARAMETERPROB. | |
1da177e4 LT |
747 | */ |
748 | ||
e3e32170 | 749 | static bool icmp_unreach(struct sk_buff *skb) |
1da177e4 | 750 | { |
b71d1d42 | 751 | const struct iphdr *iph; |
1da177e4 | 752 | struct icmphdr *icmph; |
dde1bc0e | 753 | struct net *net; |
f9242b6b | 754 | u32 info = 0; |
dde1bc0e | 755 | |
adf30907 | 756 | net = dev_net(skb_dst(skb)->dev); |
1da177e4 LT |
757 | |
758 | /* | |
759 | * Incomplete header ? | |
760 | * Only checks for the IP header, there should be an | |
761 | * additional check for longer headers in upper levels. | |
762 | */ | |
763 | ||
764 | if (!pskb_may_pull(skb, sizeof(struct iphdr))) | |
765 | goto out_err; | |
766 | ||
88c7664f | 767 | icmph = icmp_hdr(skb); |
b71d1d42 | 768 | iph = (const struct iphdr *)skb->data; |
1da177e4 LT |
769 | |
770 | if (iph->ihl < 5) /* Mangled header, drop. */ | |
771 | goto out_err; | |
772 | ||
773 | if (icmph->type == ICMP_DEST_UNREACH) { | |
774 | switch (icmph->code & 15) { | |
775 | case ICMP_NET_UNREACH: | |
776 | case ICMP_HOST_UNREACH: | |
777 | case ICMP_PROT_UNREACH: | |
778 | case ICMP_PORT_UNREACH: | |
779 | break; | |
780 | case ICMP_FRAG_NEEDED: | |
8ed1dc44 HFS |
781 | /* for documentation of the ip_no_pmtu_disc |
782 | * values please see | |
783 | * Documentation/networking/ip-sysctl.txt | |
784 | */ | |
785 | switch (net->ipv4.sysctl_ip_no_pmtu_disc) { | |
786 | default: | |
ba7a46f1 JP |
787 | net_dbg_ratelimited("%pI4: fragmentation needed and DF set\n", |
788 | &iph->daddr); | |
8ed1dc44 HFS |
789 | break; |
790 | case 2: | |
791 | goto out; | |
792 | case 3: | |
793 | if (!icmp_tag_validation(iph->protocol)) | |
794 | goto out; | |
795 | /* fall through */ | |
796 | case 0: | |
46517008 | 797 | info = ntohs(icmph->un.frag.mtu); |
1da177e4 LT |
798 | } |
799 | break; | |
800 | case ICMP_SR_FAILED: | |
ba7a46f1 JP |
801 | net_dbg_ratelimited("%pI4: Source Route Failed\n", |
802 | &iph->daddr); | |
1da177e4 LT |
803 | break; |
804 | default: | |
805 | break; | |
806 | } | |
807 | if (icmph->code > NR_ICMP_UNREACH) | |
808 | goto out; | |
809 | } else if (icmph->type == ICMP_PARAMETERPROB) | |
810 | info = ntohl(icmph->un.gateway) >> 24; | |
811 | ||
812 | /* | |
813 | * Throw it at our lower layers | |
814 | * | |
815 | * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed | |
816 | * header. | |
817 | * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the | |
818 | * transport layer. | |
819 | * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to | |
820 | * transport layer. | |
821 | */ | |
822 | ||
823 | /* | |
25985edc | 824 | * Check the other end isn't violating RFC 1122. Some routers send |
1da177e4 LT |
825 | * bogus responses to broadcast frames. If you see this message |
826 | * first check your netmask matches at both ends, if it does then | |
827 | * get the other vendor to fix their kit. | |
828 | */ | |
829 | ||
b34a95ee | 830 | if (!net->ipv4.sysctl_icmp_ignore_bogus_error_responses && |
dde1bc0e | 831 | inet_addr_type(net, iph->daddr) == RTN_BROADCAST) { |
e87cc472 JP |
832 | net_warn_ratelimited("%pI4 sent an invalid ICMP type %u, code %u error to a broadcast: %pI4 on %s\n", |
833 | &ip_hdr(skb)->saddr, | |
834 | icmph->type, icmph->code, | |
835 | &iph->daddr, skb->dev->name); | |
1da177e4 LT |
836 | goto out; |
837 | } | |
838 | ||
1de9243b | 839 | icmp_socket_deliver(skb, info); |
1da177e4 LT |
840 | |
841 | out: | |
e3e32170 | 842 | return true; |
1da177e4 | 843 | out_err: |
dcfc23ca | 844 | ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
e3e32170 | 845 | return false; |
1da177e4 LT |
846 | } |
847 | ||
848 | ||
849 | /* | |
850 | * Handle ICMP_REDIRECT. | |
851 | */ | |
852 | ||
e3e32170 | 853 | static bool icmp_redirect(struct sk_buff *skb) |
1da177e4 | 854 | { |
94206125 DM |
855 | if (skb->len < sizeof(struct iphdr)) { |
856 | ICMP_INC_STATS_BH(dev_net(skb->dev), ICMP_MIB_INERRORS); | |
e3e32170 | 857 | return false; |
94206125 | 858 | } |
1da177e4 | 859 | |
e3e32170 RJ |
860 | if (!pskb_may_pull(skb, sizeof(struct iphdr))) { |
861 | /* there aught to be a stat */ | |
862 | return false; | |
863 | } | |
c319b4d7 | 864 | |
d3351b75 | 865 | icmp_socket_deliver(skb, icmp_hdr(skb)->un.gateway); |
e3e32170 | 866 | return true; |
1da177e4 LT |
867 | } |
868 | ||
869 | /* | |
870 | * Handle ICMP_ECHO ("ping") requests. | |
871 | * | |
872 | * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo | |
873 | * requests. | |
874 | * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be | |
875 | * included in the reply. | |
876 | * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring | |
877 | * echo requests, MUST have default=NOT. | |
878 | * See also WRT handling of options once they are done and working. | |
879 | */ | |
880 | ||
e3e32170 | 881 | static bool icmp_echo(struct sk_buff *skb) |
1da177e4 | 882 | { |
b34a95ee PE |
883 | struct net *net; |
884 | ||
adf30907 | 885 | net = dev_net(skb_dst(skb)->dev); |
b34a95ee | 886 | if (!net->ipv4.sysctl_icmp_echo_ignore_all) { |
1da177e4 LT |
887 | struct icmp_bxm icmp_param; |
888 | ||
88c7664f | 889 | icmp_param.data.icmph = *icmp_hdr(skb); |
1da177e4 LT |
890 | icmp_param.data.icmph.type = ICMP_ECHOREPLY; |
891 | icmp_param.skb = skb; | |
892 | icmp_param.offset = 0; | |
893 | icmp_param.data_len = skb->len; | |
894 | icmp_param.head_len = sizeof(struct icmphdr); | |
895 | icmp_reply(&icmp_param, skb); | |
896 | } | |
e3e32170 RJ |
897 | /* should there be an ICMP stat for ignored echos? */ |
898 | return true; | |
1da177e4 LT |
899 | } |
900 | ||
901 | /* | |
902 | * Handle ICMP Timestamp requests. | |
903 | * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests. | |
904 | * SHOULD be in the kernel for minimum random latency. | |
905 | * MUST be accurate to a few minutes. | |
906 | * MUST be updated at least at 15Hz. | |
907 | */ | |
e3e32170 | 908 | static bool icmp_timestamp(struct sk_buff *skb) |
1da177e4 | 909 | { |
f25c3d61 | 910 | struct timespec tv; |
1da177e4 LT |
911 | struct icmp_bxm icmp_param; |
912 | /* | |
913 | * Too short. | |
914 | */ | |
915 | if (skb->len < 4) | |
916 | goto out_err; | |
917 | ||
918 | /* | |
919 | * Fill in the current time as ms since midnight UT: | |
920 | */ | |
f25c3d61 YH |
921 | getnstimeofday(&tv); |
922 | icmp_param.data.times[1] = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + | |
923 | tv.tv_nsec / NSEC_PER_MSEC); | |
1da177e4 LT |
924 | icmp_param.data.times[2] = icmp_param.data.times[1]; |
925 | if (skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4)) | |
926 | BUG(); | |
88c7664f | 927 | icmp_param.data.icmph = *icmp_hdr(skb); |
1da177e4 LT |
928 | icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY; |
929 | icmp_param.data.icmph.code = 0; | |
930 | icmp_param.skb = skb; | |
931 | icmp_param.offset = 0; | |
932 | icmp_param.data_len = 0; | |
933 | icmp_param.head_len = sizeof(struct icmphdr) + 12; | |
934 | icmp_reply(&icmp_param, skb); | |
e3e32170 RJ |
935 | return true; |
936 | ||
1da177e4 | 937 | out_err: |
adf30907 | 938 | ICMP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS); |
e3e32170 | 939 | return false; |
1da177e4 LT |
940 | } |
941 | ||
e3e32170 | 942 | static bool icmp_discard(struct sk_buff *skb) |
1da177e4 | 943 | { |
e3e32170 RJ |
944 | /* pretend it was a success */ |
945 | return true; | |
1da177e4 LT |
946 | } |
947 | ||
948 | /* | |
949 | * Deal with incoming ICMP packets. | |
950 | */ | |
951 | int icmp_rcv(struct sk_buff *skb) | |
952 | { | |
953 | struct icmphdr *icmph; | |
511c3f92 | 954 | struct rtable *rt = skb_rtable(skb); |
d8d1f30b | 955 | struct net *net = dev_net(rt->dst.dev); |
e3e32170 | 956 | bool success; |
1da177e4 | 957 | |
aebcf82c | 958 | if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { |
def8b4fa | 959 | struct sec_path *sp = skb_sec_path(skb); |
8b7817f3 HX |
960 | int nh; |
961 | ||
def8b4fa | 962 | if (!(sp && sp->xvec[sp->len - 1]->props.flags & |
aebcf82c HX |
963 | XFRM_STATE_ICMP)) |
964 | goto drop; | |
965 | ||
8b7817f3 HX |
966 | if (!pskb_may_pull(skb, sizeof(*icmph) + sizeof(struct iphdr))) |
967 | goto drop; | |
968 | ||
969 | nh = skb_network_offset(skb); | |
970 | skb_set_network_header(skb, sizeof(*icmph)); | |
971 | ||
972 | if (!xfrm4_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) | |
973 | goto drop; | |
974 | ||
975 | skb_set_network_header(skb, nh); | |
976 | } | |
977 | ||
dcfc23ca | 978 | ICMP_INC_STATS_BH(net, ICMP_MIB_INMSGS); |
1da177e4 | 979 | |
29a96e1f TH |
980 | if (skb_checksum_simple_validate(skb)) |
981 | goto csum_error; | |
1da177e4 | 982 | |
8cf22943 HX |
983 | if (!pskb_pull(skb, sizeof(*icmph))) |
984 | goto error; | |
1da177e4 | 985 | |
88c7664f | 986 | icmph = icmp_hdr(skb); |
1da177e4 | 987 | |
f66ac03d | 988 | ICMPMSGIN_INC_STATS_BH(net, icmph->type); |
1da177e4 LT |
989 | /* |
990 | * 18 is the highest 'known' ICMP type. Anything else is a mystery | |
991 | * | |
992 | * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently | |
993 | * discarded. | |
994 | */ | |
995 | if (icmph->type > NR_ICMP_TYPES) | |
996 | goto error; | |
997 | ||
998 | ||
999 | /* | |
1000 | * Parse the ICMP message | |
1001 | */ | |
1002 | ||
e905a9ed | 1003 | if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { |
1da177e4 LT |
1004 | /* |
1005 | * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be | |
1006 | * silently ignored (we let user decide with a sysctl). | |
1007 | * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently | |
1008 | * discarded if to broadcast/multicast. | |
1009 | */ | |
4c866aa7 AK |
1010 | if ((icmph->type == ICMP_ECHO || |
1011 | icmph->type == ICMP_TIMESTAMP) && | |
b34a95ee | 1012 | net->ipv4.sysctl_icmp_echo_ignore_broadcasts) { |
1da177e4 LT |
1013 | goto error; |
1014 | } | |
1015 | if (icmph->type != ICMP_ECHO && | |
1016 | icmph->type != ICMP_TIMESTAMP && | |
1017 | icmph->type != ICMP_ADDRESS && | |
1018 | icmph->type != ICMP_ADDRESSREPLY) { | |
1019 | goto error; | |
e905a9ed | 1020 | } |
1da177e4 LT |
1021 | } |
1022 | ||
e3e32170 RJ |
1023 | success = icmp_pointers[icmph->type].handler(skb); |
1024 | ||
1025 | if (success) { | |
1026 | consume_skb(skb); | |
1027 | return 0; | |
1028 | } | |
1da177e4 LT |
1029 | |
1030 | drop: | |
1031 | kfree_skb(skb); | |
1032 | return 0; | |
6a5dc9e5 ED |
1033 | csum_error: |
1034 | ICMP_INC_STATS_BH(net, ICMP_MIB_CSUMERRORS); | |
1da177e4 | 1035 | error: |
dcfc23ca | 1036 | ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
1da177e4 LT |
1037 | goto drop; |
1038 | } | |
1039 | ||
5b052042 LW |
1040 | void icmp_err(struct sk_buff *skb, u32 info) |
1041 | { | |
1042 | struct iphdr *iph = (struct iphdr *)skb->data; | |
6d0bfe22 LC |
1043 | int offset = iph->ihl<<2; |
1044 | struct icmphdr *icmph = (struct icmphdr *)(skb->data + offset); | |
5b052042 LW |
1045 | int type = icmp_hdr(skb)->type; |
1046 | int code = icmp_hdr(skb)->code; | |
1047 | struct net *net = dev_net(skb->dev); | |
1048 | ||
1049 | /* | |
1050 | * Use ping_err to handle all icmp errors except those | |
1051 | * triggered by ICMP_ECHOREPLY which sent from kernel. | |
1052 | */ | |
1053 | if (icmph->type != ICMP_ECHOREPLY) { | |
6d0bfe22 | 1054 | ping_err(skb, offset, info); |
5b052042 LW |
1055 | return; |
1056 | } | |
1057 | ||
1058 | if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) | |
1059 | ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ICMP, 0); | |
1060 | else if (type == ICMP_REDIRECT) | |
1061 | ipv4_redirect(skb, net, 0, 0, IPPROTO_ICMP, 0); | |
1062 | } | |
1063 | ||
1da177e4 LT |
1064 | /* |
1065 | * This table is the definition of how we handle ICMP. | |
1066 | */ | |
9b5b5cff | 1067 | static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = { |
1da177e4 | 1068 | [ICMP_ECHOREPLY] = { |
c319b4d7 | 1069 | .handler = ping_rcv, |
1da177e4 LT |
1070 | }, |
1071 | [1] = { | |
1da177e4 LT |
1072 | .handler = icmp_discard, |
1073 | .error = 1, | |
1074 | }, | |
1075 | [2] = { | |
1da177e4 LT |
1076 | .handler = icmp_discard, |
1077 | .error = 1, | |
1078 | }, | |
1079 | [ICMP_DEST_UNREACH] = { | |
1da177e4 LT |
1080 | .handler = icmp_unreach, |
1081 | .error = 1, | |
1082 | }, | |
1083 | [ICMP_SOURCE_QUENCH] = { | |
1da177e4 LT |
1084 | .handler = icmp_unreach, |
1085 | .error = 1, | |
1086 | }, | |
1087 | [ICMP_REDIRECT] = { | |
1da177e4 LT |
1088 | .handler = icmp_redirect, |
1089 | .error = 1, | |
1090 | }, | |
1091 | [6] = { | |
1da177e4 LT |
1092 | .handler = icmp_discard, |
1093 | .error = 1, | |
1094 | }, | |
1095 | [7] = { | |
1da177e4 LT |
1096 | .handler = icmp_discard, |
1097 | .error = 1, | |
1098 | }, | |
1099 | [ICMP_ECHO] = { | |
1da177e4 LT |
1100 | .handler = icmp_echo, |
1101 | }, | |
1102 | [9] = { | |
1da177e4 LT |
1103 | .handler = icmp_discard, |
1104 | .error = 1, | |
1105 | }, | |
1106 | [10] = { | |
1da177e4 LT |
1107 | .handler = icmp_discard, |
1108 | .error = 1, | |
1109 | }, | |
1110 | [ICMP_TIME_EXCEEDED] = { | |
1da177e4 LT |
1111 | .handler = icmp_unreach, |
1112 | .error = 1, | |
1113 | }, | |
1114 | [ICMP_PARAMETERPROB] = { | |
1da177e4 LT |
1115 | .handler = icmp_unreach, |
1116 | .error = 1, | |
1117 | }, | |
1118 | [ICMP_TIMESTAMP] = { | |
1da177e4 LT |
1119 | .handler = icmp_timestamp, |
1120 | }, | |
1121 | [ICMP_TIMESTAMPREPLY] = { | |
1da177e4 LT |
1122 | .handler = icmp_discard, |
1123 | }, | |
1124 | [ICMP_INFO_REQUEST] = { | |
1da177e4 LT |
1125 | .handler = icmp_discard, |
1126 | }, | |
e905a9ed | 1127 | [ICMP_INFO_REPLY] = { |
1da177e4 LT |
1128 | .handler = icmp_discard, |
1129 | }, | |
1130 | [ICMP_ADDRESS] = { | |
838942a5 | 1131 | .handler = icmp_discard, |
1da177e4 LT |
1132 | }, |
1133 | [ICMP_ADDRESSREPLY] = { | |
838942a5 | 1134 | .handler = icmp_discard, |
1da177e4 LT |
1135 | }, |
1136 | }; | |
1137 | ||
4a6ad7a1 | 1138 | static void __net_exit icmp_sk_exit(struct net *net) |
1da177e4 | 1139 | { |
1da177e4 LT |
1140 | int i; |
1141 | ||
5c8cafd6 | 1142 | for_each_possible_cpu(i) |
349c9e3c ED |
1143 | inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.icmp_sk, i)); |
1144 | free_percpu(net->ipv4.icmp_sk); | |
4a6ad7a1 | 1145 | net->ipv4.icmp_sk = NULL; |
a5710d65 | 1146 | } |
1da177e4 | 1147 | |
263173af | 1148 | static int __net_init icmp_sk_init(struct net *net) |
a5710d65 | 1149 | { |
a5710d65 DL |
1150 | int i, err; |
1151 | ||
349c9e3c ED |
1152 | net->ipv4.icmp_sk = alloc_percpu(struct sock *); |
1153 | if (!net->ipv4.icmp_sk) | |
79c91159 DL |
1154 | return -ENOMEM; |
1155 | ||
a5710d65 | 1156 | for_each_possible_cpu(i) { |
1e3cf683 | 1157 | struct sock *sk; |
1da177e4 | 1158 | |
c1e9894d DL |
1159 | err = inet_ctl_sock_create(&sk, PF_INET, |
1160 | SOCK_RAW, IPPROTO_ICMP, net); | |
1da177e4 | 1161 | if (err < 0) |
a5710d65 | 1162 | goto fail; |
1da177e4 | 1163 | |
349c9e3c | 1164 | *per_cpu_ptr(net->ipv4.icmp_sk, i) = sk; |
1da177e4 LT |
1165 | |
1166 | /* Enough space for 2 64K ICMP packets, including | |
87fb4b7b | 1167 | * sk_buff/skb_shared_info struct overhead. |
1da177e4 | 1168 | */ |
87fb4b7b | 1169 | sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); |
1da177e4 | 1170 | |
b3a5b6cc ED |
1171 | /* |
1172 | * Speedup sock_wfree() | |
1173 | */ | |
1174 | sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); | |
c1e9894d | 1175 | inet_sk(sk)->pmtudisc = IP_PMTUDISC_DONT; |
1da177e4 | 1176 | } |
a24022e1 PE |
1177 | |
1178 | /* Control parameters for ECHO replies. */ | |
1179 | net->ipv4.sysctl_icmp_echo_ignore_all = 0; | |
1180 | net->ipv4.sysctl_icmp_echo_ignore_broadcasts = 1; | |
1181 | ||
1182 | /* Control parameter - ignore bogus broadcast responses? */ | |
1183 | net->ipv4.sysctl_icmp_ignore_bogus_error_responses = 1; | |
1184 | ||
1185 | /* | |
1186 | * Configurable global rate limit. | |
1187 | * | |
1188 | * ratelimit defines tokens/packet consumed for dst->rate_token | |
1189 | * bucket ratemask defines which icmp types are ratelimited by | |
1190 | * setting it's bit position. | |
1191 | * | |
1192 | * default: | |
1193 | * dest unreachable (3), source quench (4), | |
1194 | * time exceeded (11), parameter problem (12) | |
1195 | */ | |
1196 | ||
1197 | net->ipv4.sysctl_icmp_ratelimit = 1 * HZ; | |
1198 | net->ipv4.sysctl_icmp_ratemask = 0x1818; | |
1199 | net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr = 0; | |
1200 | ||
a5710d65 DL |
1201 | return 0; |
1202 | ||
1203 | fail: | |
1d1c8d13 | 1204 | for_each_possible_cpu(i) |
349c9e3c ED |
1205 | inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.icmp_sk, i)); |
1206 | free_percpu(net->ipv4.icmp_sk); | |
a5710d65 | 1207 | return err; |
1da177e4 LT |
1208 | } |
1209 | ||
4a6ad7a1 DL |
1210 | static struct pernet_operations __net_initdata icmp_sk_ops = { |
1211 | .init = icmp_sk_init, | |
1212 | .exit = icmp_sk_exit, | |
1213 | }; | |
1214 | ||
1215 | int __init icmp_init(void) | |
1216 | { | |
959d2726 | 1217 | return register_pernet_subsys(&icmp_sk_ops); |
4a6ad7a1 | 1218 | } |