blob: 1771ce662548d510c0eb4a783fc75866010b2f13 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * NET3: Implementation of the ICMP protocol layer.
3 *
Alan Cox113aa832008-10-13 19:01:08 -07004 * Alan Cox, <alan@lxorguk.ukuu.org.uk>
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 * 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070065#include <linux/module.h>
66#include <linux/types.h>
67#include <linux/jiffies.h>
68#include <linux/kernel.h>
69#include <linux/fcntl.h>
70#include <linux/socket.h>
71#include <linux/in.h>
72#include <linux/inet.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020073#include <linux/inetdevice.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070074#include <linux/netdevice.h>
75#include <linux/string.h>
76#include <linux/netfilter_ipv4.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090077#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070078#include <net/snmp.h>
79#include <net/ip.h>
80#include <net/route.h>
81#include <net/protocol.h>
82#include <net/icmp.h>
83#include <net/tcp.h>
84#include <net/udp.h>
85#include <net/raw.h>
86#include <linux/skbuff.h>
87#include <net/sock.h>
88#include <linux/errno.h>
89#include <linux/timer.h>
90#include <linux/init.h>
91#include <asm/system.h>
92#include <asm/uaccess.h>
93#include <net/checksum.h>
Herbert Xu8b7817f2007-12-12 10:44:43 -080094#include <net/xfrm.h>
Denis V. Lunevc1e98942008-04-03 14:29:00 -070095#include <net/inet_common.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
97/*
98 * Build xmit assembly blocks
99 */
100
101struct icmp_bxm {
102 struct sk_buff *skb;
103 int offset;
104 int data_len;
105
106 struct {
107 struct icmphdr icmph;
Al Virob03d73e2006-09-27 18:38:30 -0700108 __be32 times[3];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 } data;
110 int head_len;
111 struct ip_options replyopts;
112 unsigned char optbuf[40];
113};
114
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115/* An array of errno for error messages from dest unreach. */
116/* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
117
Alexey Dobriyane7548342010-01-22 10:18:25 +0000118const struct icmp_err icmp_err_convert[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 {
120 .errno = ENETUNREACH, /* ICMP_NET_UNREACH */
121 .fatal = 0,
122 },
123 {
124 .errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */
125 .fatal = 0,
126 },
127 {
128 .errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */,
129 .fatal = 1,
130 },
131 {
132 .errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */
133 .fatal = 1,
134 },
135 {
136 .errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */
137 .fatal = 0,
138 },
139 {
140 .errno = EOPNOTSUPP, /* ICMP_SR_FAILED */
141 .fatal = 0,
142 },
143 {
144 .errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */
145 .fatal = 1,
146 },
147 {
148 .errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */
149 .fatal = 1,
150 },
151 {
152 .errno = ENONET, /* ICMP_HOST_ISOLATED */
153 .fatal = 1,
154 },
155 {
156 .errno = ENETUNREACH, /* ICMP_NET_ANO */
157 .fatal = 1,
158 },
159 {
160 .errno = EHOSTUNREACH, /* ICMP_HOST_ANO */
161 .fatal = 1,
162 },
163 {
164 .errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */
165 .fatal = 0,
166 },
167 {
168 .errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */
169 .fatal = 0,
170 },
171 {
172 .errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */
173 .fatal = 1,
174 },
175 {
176 .errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */
177 .fatal = 1,
178 },
179 {
180 .errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */
181 .fatal = 1,
182 },
183};
Eric Dumazet4bc2f182010-07-09 21:22:10 +0000184EXPORT_SYMBOL(icmp_err_convert);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186/*
187 * ICMP control array. This specifies what to do with each ICMP.
188 */
189
190struct icmp_control {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 void (*handler)(struct sk_buff *skb);
192 short error; /* This ICMP is classed as an error message */
193};
194
Arjan van de Ven9b5b5cf2005-11-29 16:21:38 -0800195static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196
197/*
198 * The ICMP socket(s). This is the most convenient way to flow control
199 * our ICMP output as well as maintain a clean interface throughout
200 * all layers. All Socketless IP sends will soon be gone.
201 *
202 * On SMP we have one ICMP socket per-cpu.
203 */
Denis V. Lunev4a6ad7a2008-02-29 11:19:58 -0800204static struct sock *icmp_sk(struct net *net)
205{
206 return net->ipv4.icmp_sk[smp_processor_id()];
207}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208
Denis V. Lunevfdc0bde2008-08-23 04:43:33 -0700209static inline struct sock *icmp_xmit_lock(struct net *net)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210{
Denis V. Lunevfdc0bde2008-08-23 04:43:33 -0700211 struct sock *sk;
212
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 local_bh_disable();
214
Denis V. Lunevfdc0bde2008-08-23 04:43:33 -0700215 sk = icmp_sk(net);
216
Denis V. Lunev405666d2008-02-29 11:16:46 -0800217 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 /* This can happen if the output path signals a
219 * dst_link_failure() for an outgoing ICMP packet.
220 */
221 local_bh_enable();
Denis V. Lunevfdc0bde2008-08-23 04:43:33 -0700222 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 }
Denis V. Lunevfdc0bde2008-08-23 04:43:33 -0700224 return sk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225}
226
Denis V. Lunev405666d2008-02-29 11:16:46 -0800227static inline void icmp_xmit_unlock(struct sock *sk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228{
Denis V. Lunev405666d2008-02-29 11:16:46 -0800229 spin_unlock_bh(&sk->sk_lock.slock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230}
231
232/*
233 * Send an ICMP frame.
234 */
235
David S. Miller92d86822011-02-04 15:55:25 -0800236static inline bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
Pavel Emelyanovb34a95e2008-03-26 02:00:21 -0700237 int type, int code)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238{
Changli Gaod8d1f302010-06-10 23:31:35 -0700239 struct dst_entry *dst = &rt->dst;
David S. Miller92d86822011-02-04 15:55:25 -0800240 bool rc = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241
242 if (type > NR_ICMP_TYPES)
243 goto out;
244
245 /* Don't limit PMTU discovery. */
246 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
247 goto out;
248
249 /* No rate limit on loopback */
250 if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900251 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
253 /* Limit if icmp type is enabled in ratemask. */
David S. Miller92d86822011-02-04 15:55:25 -0800254 if ((1 << type) & net->ipv4.sysctl_icmp_ratemask) {
255 if (!rt->peer)
256 rt_bind_peer(rt, 1);
257 rc = inet_peer_xrlim_allow(rt->peer,
258 net->ipv4.sysctl_icmp_ratelimit);
259 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260out:
261 return rc;
262}
263
264/*
265 * Maintain the counters used in the SNMP statistics for outgoing ICMP
266 */
Pavel Emelyanov0388b002008-07-14 23:00:43 -0700267void icmp_out_count(struct net *net, unsigned char type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268{
Pavel Emelyanov903fc192008-07-14 23:03:35 -0700269 ICMPMSGOUT_INC_STATS(net, type);
Pavel Emelyanov75c939b2008-07-14 23:02:35 -0700270 ICMP_INC_STATS(net, ICMP_MIB_OUTMSGS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271}
272
273/*
274 * Checksum each fragment, and on the first include the headers and final
275 * checksum.
276 */
277static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
278 struct sk_buff *skb)
279{
280 struct icmp_bxm *icmp_param = (struct icmp_bxm *)from;
Al Viro5f92a732006-11-14 21:36:54 -0800281 __wsum csum;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282
283 csum = skb_copy_and_csum_bits(icmp_param->skb,
284 icmp_param->offset + offset,
285 to, len, 0);
286
287 skb->csum = csum_block_add(skb->csum, csum, odd);
288 if (icmp_pointers[icmp_param->data.icmph.type].error)
289 nf_ct_attach(skb, icmp_param->skb);
290 return 0;
291}
292
293static void icmp_push_reply(struct icmp_bxm *icmp_param,
Eric Dumazet2e77d892008-11-24 15:52:46 -0800294 struct ipcm_cookie *ipc, struct rtable **rt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295{
Denis V. Lunev1e3cf682008-02-29 11:15:42 -0800296 struct sock *sk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 struct sk_buff *skb;
298
Changli Gaod8d1f302010-06-10 23:31:35 -0700299 sk = icmp_sk(dev_net((*rt)->dst.dev));
Denis V. Lunev1e3cf682008-02-29 11:15:42 -0800300 if (ip_append_data(sk, icmp_glue_bits, icmp_param,
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900301 icmp_param->data_len+icmp_param->head_len,
302 icmp_param->head_len,
Eric Dumazet1f8438a2010-04-03 15:09:04 -0700303 ipc, rt, MSG_DONTWAIT) < 0) {
304 ICMP_INC_STATS_BH(sock_net(sk), ICMP_MIB_OUTERRORS);
Denis V. Lunev1e3cf682008-02-29 11:15:42 -0800305 ip_flush_pending_frames(sk);
Eric Dumazet1f8438a2010-04-03 15:09:04 -0700306 } else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300307 struct icmphdr *icmph = icmp_hdr(skb);
Al Virod3bc23e2006-11-14 21:24:49 -0800308 __wsum csum = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 struct sk_buff *skb1;
310
Denis V. Lunev1e3cf682008-02-29 11:15:42 -0800311 skb_queue_walk(&sk->sk_write_queue, skb1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 csum = csum_add(csum, skb1->csum);
313 }
314 csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
315 (char *)icmph,
316 icmp_param->head_len, csum);
317 icmph->checksum = csum_fold(csum);
318 skb->ip_summed = CHECKSUM_NONE;
Denis V. Lunev1e3cf682008-02-29 11:15:42 -0800319 ip_push_pending_frames(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 }
321}
322
323/*
324 * Driving logic for building and sending ICMP messages.
325 */
326
327static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
328{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 struct ipcm_cookie ipc;
Eric Dumazet511c3f92009-06-02 05:14:27 +0000330 struct rtable *rt = skb_rtable(skb);
Changli Gaod8d1f302010-06-10 23:31:35 -0700331 struct net *net = dev_net(rt->dst.dev);
Denis V. Lunevfdc0bde2008-08-23 04:43:33 -0700332 struct sock *sk;
333 struct inet_sock *inet;
Al Viro3ca3c682006-09-27 18:28:07 -0700334 __be32 daddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335
336 if (ip_options_echo(&icmp_param->replyopts, skb))
Hormsf00c4012006-02-02 17:03:18 -0800337 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338
Denis V. Lunevfdc0bde2008-08-23 04:43:33 -0700339 sk = icmp_xmit_lock(net);
340 if (sk == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 return;
Denis V. Lunevfdc0bde2008-08-23 04:43:33 -0700342 inet = inet_sk(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343
344 icmp_param->data.icmph.checksum = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700346 inet->tos = ip_hdr(skb)->tos;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 daddr = ipc.addr = rt->rt_src;
348 ipc.opt = NULL;
Oliver Hartkopp2244d072010-08-17 08:59:14 +0000349 ipc.tx_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 if (icmp_param->replyopts.optlen) {
351 ipc.opt = &icmp_param->replyopts;
352 if (ipc.opt->srr)
353 daddr = icmp_param->replyopts.faddr;
354 }
355 {
Changli Gao58116622010-11-12 18:43:55 +0000356 struct flowi fl = { .fl4_dst= daddr,
357 .fl4_src = rt->rt_spec_dst,
358 .fl4_tos = RT_TOS(ip_hdr(skb)->tos),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 .proto = IPPROTO_ICMP };
Venkat Yekkiralabeb8d132006-08-04 23:12:42 -0700360 security_skb_classify_flow(skb, &fl);
David S. Millerb23dd4f2011-03-02 14:31:35 -0800361 rt = ip_route_output_key(net, &fl);
362 if (IS_ERR(rt))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 goto out_unlock;
364 }
Pavel Emelyanovb34a95e2008-03-26 02:00:21 -0700365 if (icmpv4_xrlim_allow(net, rt, icmp_param->data.icmph.type,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 icmp_param->data.icmph.code))
Eric Dumazet2e77d892008-11-24 15:52:46 -0800367 icmp_push_reply(icmp_param, &ipc, &rt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 ip_rt_put(rt);
369out_unlock:
Denis V. Lunev405666d2008-02-29 11:16:46 -0800370 icmp_xmit_unlock(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371}
372
David S. Millerf6d460c2011-03-01 15:49:55 -0800373static struct rtable *icmp_route_lookup(struct net *net, struct sk_buff *skb_in,
374 struct iphdr *iph,
375 __be32 saddr, u8 tos,
376 int type, int code,
377 struct icmp_bxm *param)
378{
379 struct flowi fl = {
380 .fl4_dst = (param->replyopts.srr ?
381 param->replyopts.faddr : iph->saddr),
382 .fl4_src = saddr,
383 .fl4_tos = RT_TOS(tos),
384 .proto = IPPROTO_ICMP,
385 .fl_icmp_type = type,
386 .fl_icmp_code = code,
387 };
388 struct rtable *rt, *rt2;
389 int err;
390
391 security_skb_classify_flow(skb_in, &fl);
David S. Millerb23dd4f2011-03-02 14:31:35 -0800392 rt = __ip_route_output_key(net, &fl);
393 if (IS_ERR(rt))
394 return rt;
David S. Millerf6d460c2011-03-01 15:49:55 -0800395
396 /* No need to clone since we're just using its address. */
397 rt2 = rt;
398
399 if (!fl.fl4_src)
400 fl.fl4_src = rt->rt_src;
401
David S. Miller452edd52011-03-02 13:27:41 -0800402 rt = (struct rtable *) xfrm_lookup(net, &rt->dst, &fl, NULL, 0);
403 if (!IS_ERR(rt)) {
David S. Millerf6d460c2011-03-01 15:49:55 -0800404 if (rt != rt2)
405 return rt;
David S. Miller452edd52011-03-02 13:27:41 -0800406 } else if (PTR_ERR(rt) == -EPERM) {
David S. Millerf6d460c2011-03-01 15:49:55 -0800407 rt = NULL;
David S. Miller452edd52011-03-02 13:27:41 -0800408 } else
409 return rt;
David S. Millerf6d460c2011-03-01 15:49:55 -0800410
411 err = xfrm_decode_session_reverse(skb_in, &fl, AF_INET);
412 if (err)
413 goto relookup_failed;
414
415 if (inet_addr_type(net, fl.fl4_src) == RTN_LOCAL) {
David S. Millerb23dd4f2011-03-02 14:31:35 -0800416 rt2 = __ip_route_output_key(net, &fl);
417 if (IS_ERR(rt2))
418 err = PTR_ERR(rt2);
David S. Millerf6d460c2011-03-01 15:49:55 -0800419 } else {
420 struct flowi fl2 = {};
421 unsigned long orefdst;
422
423 fl2.fl4_dst = fl.fl4_src;
David S. Millerb23dd4f2011-03-02 14:31:35 -0800424 rt2 = ip_route_output_key(net, &fl2);
425 if (IS_ERR(rt2)) {
426 err = PTR_ERR(rt2);
David S. Millerf6d460c2011-03-01 15:49:55 -0800427 goto relookup_failed;
David S. Millerb23dd4f2011-03-02 14:31:35 -0800428 }
David S. Millerf6d460c2011-03-01 15:49:55 -0800429 /* Ugh! */
430 orefdst = skb_in->_skb_refdst; /* save old refdst */
431 err = ip_route_input(skb_in, fl.fl4_dst, fl.fl4_src,
432 RT_TOS(tos), rt2->dst.dev);
433
434 dst_release(&rt2->dst);
435 rt2 = skb_rtable(skb_in);
436 skb_in->_skb_refdst = orefdst; /* restore old refdst */
437 }
438
439 if (err)
440 goto relookup_failed;
441
David S. Miller452edd52011-03-02 13:27:41 -0800442 rt2 = (struct rtable *) xfrm_lookup(net, &rt2->dst, &fl, NULL, XFRM_LOOKUP_ICMP);
443 if (!IS_ERR(rt2)) {
David S. Millerf6d460c2011-03-01 15:49:55 -0800444 dst_release(&rt->dst);
445 rt = rt2;
David S. Miller452edd52011-03-02 13:27:41 -0800446 } else if (PTR_ERR(rt2) == -EPERM) {
447 if (rt)
448 dst_release(&rt->dst);
449 return rt2;
450 } else {
451 err = PTR_ERR(rt2);
452 goto relookup_failed;
David S. Millerf6d460c2011-03-01 15:49:55 -0800453 }
David S. Millerf6d460c2011-03-01 15:49:55 -0800454 return rt;
455
456relookup_failed:
457 if (rt)
458 return rt;
459 return ERR_PTR(err);
460}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461
462/*
463 * Send an ICMP message in response to a situation
464 *
465 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
466 * MAY send more (we do).
467 * MUST NOT change this header information.
468 * MUST NOT reply to a multicast/broadcast IP address.
469 * MUST NOT reply to a multicast/broadcast MAC address.
470 * MUST reply to only the first fragment.
471 */
472
Al Viroe4883012006-09-26 22:17:28 -0700473void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474{
475 struct iphdr *iph;
476 int room;
477 struct icmp_bxm icmp_param;
Eric Dumazet511c3f92009-06-02 05:14:27 +0000478 struct rtable *rt = skb_rtable(skb_in);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 struct ipcm_cookie ipc;
Al Viroa61ced52006-09-26 21:27:54 -0700480 __be32 saddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 u8 tos;
Denis V. Lunevdde1bc02008-01-22 23:50:57 -0800482 struct net *net;
Denis V. Lunev4a6ad7a2008-02-29 11:19:58 -0800483 struct sock *sk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484
485 if (!rt)
486 goto out;
Changli Gaod8d1f302010-06-10 23:31:35 -0700487 net = dev_net(rt->dst.dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488
489 /*
490 * Find the original header. It is expected to be valid, of course.
491 * Check this, icmp_send is called from the most obscure devices
492 * sometimes.
493 */
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700494 iph = ip_hdr(skb_in);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700496 if ((u8 *)iph < skb_in->head ||
497 (skb_in->network_header + sizeof(*iph)) > skb_in->tail)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 goto out;
499
500 /*
501 * No replies to physical multicast/broadcast
502 */
503 if (skb_in->pkt_type != PACKET_HOST)
504 goto out;
505
506 /*
507 * Now check at the protocol level
508 */
509 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
510 goto out;
511
512 /*
513 * Only reply to fragment 0. We byte re-order the constant
514 * mask for efficiency.
515 */
516 if (iph->frag_off & htons(IP_OFFSET))
517 goto out;
518
519 /*
520 * If we send an ICMP error to an ICMP error a mess would result..
521 */
522 if (icmp_pointers[type].error) {
523 /*
524 * We are an error, check if we are replying to an
525 * ICMP error
526 */
527 if (iph->protocol == IPPROTO_ICMP) {
528 u8 _inner_type, *itp;
529
530 itp = skb_header_pointer(skb_in,
Arnaldo Carvalho de Melod56f90a2007-04-10 20:50:43 -0700531 skb_network_header(skb_in) +
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 (iph->ihl << 2) +
533 offsetof(struct icmphdr,
534 type) -
535 skb_in->data,
536 sizeof(_inner_type),
537 &_inner_type);
538 if (itp == NULL)
539 goto out;
540
541 /*
542 * Assume any unknown ICMP type is an error. This
543 * isn't specified by the RFC, but think about it..
544 */
545 if (*itp > NR_ICMP_TYPES ||
546 icmp_pointers[*itp].error)
547 goto out;
548 }
549 }
550
Denis V. Lunevfdc0bde2008-08-23 04:43:33 -0700551 sk = icmp_xmit_lock(net);
552 if (sk == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 return;
554
555 /*
556 * Construct source address and options.
557 */
558
559 saddr = iph->daddr;
J. Simonetti1c2fb7f2005-06-13 15:19:03 -0700560 if (!(rt->rt_flags & RTCF_LOCAL)) {
Patrick McHardy6e1d9102007-06-01 11:45:04 -0700561 struct net_device *dev = NULL;
562
Eric Dumazet685c7942009-11-01 19:31:03 +0000563 rcu_read_lock();
David S. Millerc7537962010-11-11 17:07:48 -0800564 if (rt_is_input_route(rt) &&
565 net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr)
David S. Miller5e2b61f2011-03-04 21:47:09 -0800566 dev = dev_get_by_index_rcu(net, rt->rt_iif);
Patrick McHardy6e1d9102007-06-01 11:45:04 -0700567
Eric Dumazet685c7942009-11-01 19:31:03 +0000568 if (dev)
Patrick McHardy6e1d9102007-06-01 11:45:04 -0700569 saddr = inet_select_addr(dev, 0, RT_SCOPE_LINK);
Eric Dumazet685c7942009-11-01 19:31:03 +0000570 else
J. Simonetti1c2fb7f2005-06-13 15:19:03 -0700571 saddr = 0;
Eric Dumazet685c7942009-11-01 19:31:03 +0000572 rcu_read_unlock();
J. Simonetti1c2fb7f2005-06-13 15:19:03 -0700573 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574
575 tos = icmp_pointers[type].error ? ((iph->tos & IPTOS_TOS_MASK) |
576 IPTOS_PREC_INTERNETCONTROL) :
577 iph->tos;
578
579 if (ip_options_echo(&icmp_param.replyopts, skb_in))
Herbert Xufa60cf72006-02-04 02:09:34 -0800580 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581
582
583 /*
584 * Prepare data for ICMP header.
585 */
586
587 icmp_param.data.icmph.type = type;
588 icmp_param.data.icmph.code = code;
589 icmp_param.data.icmph.un.gateway = info;
590 icmp_param.data.icmph.checksum = 0;
591 icmp_param.skb = skb_in;
Arnaldo Carvalho de Melod56f90a2007-04-10 20:50:43 -0700592 icmp_param.offset = skb_network_offset(skb_in);
Denis V. Lunev405666d2008-02-29 11:16:46 -0800593 inet_sk(sk)->tos = tos;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 ipc.addr = iph->saddr;
595 ipc.opt = &icmp_param.replyopts;
Oliver Hartkopp2244d072010-08-17 08:59:14 +0000596 ipc.tx_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597
David S. Millerf6d460c2011-03-01 15:49:55 -0800598 rt = icmp_route_lookup(net, skb_in, iph, saddr, tos,
599 type, code, &icmp_param);
600 if (IS_ERR(rt))
601 goto out_unlock;
Herbert Xu8b7817f2007-12-12 10:44:43 -0800602
Pavel Emelyanovb34a95e2008-03-26 02:00:21 -0700603 if (!icmpv4_xrlim_allow(net, rt, type, code))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604 goto ende;
605
606 /* RFC says return as much as we can without exceeding 576 bytes. */
607
Changli Gaod8d1f302010-06-10 23:31:35 -0700608 room = dst_mtu(&rt->dst);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 if (room > 576)
610 room = 576;
611 room -= sizeof(struct iphdr) + icmp_param.replyopts.optlen;
612 room -= sizeof(struct icmphdr);
613
614 icmp_param.data_len = skb_in->len - icmp_param.offset;
615 if (icmp_param.data_len > room)
616 icmp_param.data_len = room;
617 icmp_param.head_len = sizeof(struct icmphdr);
618
Eric Dumazet2e77d892008-11-24 15:52:46 -0800619 icmp_push_reply(&icmp_param, &ipc, &rt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620ende:
621 ip_rt_put(rt);
622out_unlock:
Denis V. Lunev405666d2008-02-29 11:16:46 -0800623 icmp_xmit_unlock(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624out:;
625}
Eric Dumazet4bc2f182010-07-09 21:22:10 +0000626EXPORT_SYMBOL(icmp_send);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627
628
629/*
630 * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEED, and ICMP_QUENCH.
631 */
632
633static void icmp_unreach(struct sk_buff *skb)
634{
635 struct iphdr *iph;
636 struct icmphdr *icmph;
637 int hash, protocol;
Alexey Dobriyan32613092009-09-14 12:21:47 +0000638 const struct net_protocol *ipprot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 u32 info = 0;
Denis V. Lunevdde1bc02008-01-22 23:50:57 -0800640 struct net *net;
641
Eric Dumazetadf30902009-06-02 05:19:30 +0000642 net = dev_net(skb_dst(skb)->dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643
644 /*
645 * Incomplete header ?
646 * Only checks for the IP header, there should be an
647 * additional check for longer headers in upper levels.
648 */
649
650 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
651 goto out_err;
652
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300653 icmph = icmp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 iph = (struct iphdr *)skb->data;
655
656 if (iph->ihl < 5) /* Mangled header, drop. */
657 goto out_err;
658
659 if (icmph->type == ICMP_DEST_UNREACH) {
660 switch (icmph->code & 15) {
661 case ICMP_NET_UNREACH:
662 case ICMP_HOST_UNREACH:
663 case ICMP_PROT_UNREACH:
664 case ICMP_PORT_UNREACH:
665 break;
666 case ICMP_FRAG_NEEDED:
667 if (ipv4_config.no_pmtu_disc) {
Harvey Harrison673d57e2008-10-31 00:53:57 -0700668 LIMIT_NETDEBUG(KERN_INFO "ICMP: %pI4: fragmentation needed and DF set.\n",
669 &iph->daddr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 } else {
Denis V. Lunevdde1bc02008-01-22 23:50:57 -0800671 info = ip_rt_frag_needed(net, iph,
Timo Teras0010e462008-04-29 03:32:25 -0700672 ntohs(icmph->un.frag.mtu),
673 skb->dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 if (!info)
675 goto out;
676 }
677 break;
678 case ICMP_SR_FAILED:
Harvey Harrison673d57e2008-10-31 00:53:57 -0700679 LIMIT_NETDEBUG(KERN_INFO "ICMP: %pI4: Source Route Failed.\n",
680 &iph->daddr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 break;
682 default:
683 break;
684 }
685 if (icmph->code > NR_ICMP_UNREACH)
686 goto out;
687 } else if (icmph->type == ICMP_PARAMETERPROB)
688 info = ntohl(icmph->un.gateway) >> 24;
689
690 /*
691 * Throw it at our lower layers
692 *
693 * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed
694 * header.
695 * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
696 * transport layer.
697 * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
698 * transport layer.
699 */
700
701 /*
702 * Check the other end isnt violating RFC 1122. Some routers send
703 * bogus responses to broadcast frames. If you see this message
704 * first check your netmask matches at both ends, if it does then
705 * get the other vendor to fix their kit.
706 */
707
Pavel Emelyanovb34a95e2008-03-26 02:00:21 -0700708 if (!net->ipv4.sysctl_icmp_ignore_bogus_error_responses &&
Denis V. Lunevdde1bc02008-01-22 23:50:57 -0800709 inet_addr_type(net, iph->daddr) == RTN_BROADCAST) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 if (net_ratelimit())
Harvey Harrison673d57e2008-10-31 00:53:57 -0700711 printk(KERN_WARNING "%pI4 sent an invalid ICMP "
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 "type %u, code %u "
Harvey Harrison673d57e2008-10-31 00:53:57 -0700713 "error to a broadcast: %pI4 on %s\n",
714 &ip_hdr(skb)->saddr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 icmph->type, icmph->code,
Harvey Harrison673d57e2008-10-31 00:53:57 -0700716 &iph->daddr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 skb->dev->name);
718 goto out;
719 }
720
721 /* Checkin full IP header plus 8 bytes of protocol to
722 * avoid additional coding at protocol handlers.
723 */
724 if (!pskb_may_pull(skb, iph->ihl * 4 + 8))
725 goto out;
726
727 iph = (struct iphdr *)skb->data;
728 protocol = iph->protocol;
729
730 /*
731 * Deliver ICMP message to raw sockets. Pretty useless feature?
732 */
Pavel Emelyanov7bc54c92007-11-19 22:35:07 -0800733 raw_icmp_error(skb, protocol, info);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 hash = protocol & (MAX_INET_PROTOS - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 rcu_read_lock();
737 ipprot = rcu_dereference(inet_protos[hash]);
738 if (ipprot && ipprot->err_handler)
739 ipprot->err_handler(skb, info);
740 rcu_read_unlock();
741
742out:
743 return;
744out_err:
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700745 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 goto out;
747}
748
749
750/*
751 * Handle ICMP_REDIRECT.
752 */
753
754static void icmp_redirect(struct sk_buff *skb)
755{
756 struct iphdr *iph;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757
758 if (skb->len < sizeof(struct iphdr))
759 goto out_err;
760
761 /*
762 * Get the copied header of the packet that caused the redirect
763 */
764 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
765 goto out;
766
767 iph = (struct iphdr *)skb->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300769 switch (icmp_hdr(skb)->code & 7) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 case ICMP_REDIR_NET:
771 case ICMP_REDIR_NETTOS:
772 /*
773 * As per RFC recommendations now handle it as a host redirect.
774 */
775 case ICMP_REDIR_HOST:
776 case ICMP_REDIR_HOSTTOS:
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700777 ip_rt_redirect(ip_hdr(skb)->saddr, iph->daddr,
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300778 icmp_hdr(skb)->un.gateway,
Ilia Sotnikovcef26852006-03-25 01:38:55 -0800779 iph->saddr, skb->dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 break;
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900781 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782out:
783 return;
784out_err:
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700785 ICMP_INC_STATS_BH(dev_net(skb->dev), ICMP_MIB_INERRORS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 goto out;
787}
788
789/*
790 * Handle ICMP_ECHO ("ping") requests.
791 *
792 * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
793 * requests.
794 * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be
795 * included in the reply.
796 * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring
797 * echo requests, MUST have default=NOT.
798 * See also WRT handling of options once they are done and working.
799 */
800
801static void icmp_echo(struct sk_buff *skb)
802{
Pavel Emelyanovb34a95e2008-03-26 02:00:21 -0700803 struct net *net;
804
Eric Dumazetadf30902009-06-02 05:19:30 +0000805 net = dev_net(skb_dst(skb)->dev);
Pavel Emelyanovb34a95e2008-03-26 02:00:21 -0700806 if (!net->ipv4.sysctl_icmp_echo_ignore_all) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 struct icmp_bxm icmp_param;
808
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300809 icmp_param.data.icmph = *icmp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 icmp_param.data.icmph.type = ICMP_ECHOREPLY;
811 icmp_param.skb = skb;
812 icmp_param.offset = 0;
813 icmp_param.data_len = skb->len;
814 icmp_param.head_len = sizeof(struct icmphdr);
815 icmp_reply(&icmp_param, skb);
816 }
817}
818
819/*
820 * Handle ICMP Timestamp requests.
821 * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests.
822 * SHOULD be in the kernel for minimum random latency.
823 * MUST be accurate to a few minutes.
824 * MUST be updated at least at 15Hz.
825 */
826static void icmp_timestamp(struct sk_buff *skb)
827{
YOSHIFUJI Hideakif25c3d62008-04-21 02:34:08 -0700828 struct timespec tv;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 struct icmp_bxm icmp_param;
830 /*
831 * Too short.
832 */
833 if (skb->len < 4)
834 goto out_err;
835
836 /*
837 * Fill in the current time as ms since midnight UT:
838 */
YOSHIFUJI Hideakif25c3d62008-04-21 02:34:08 -0700839 getnstimeofday(&tv);
840 icmp_param.data.times[1] = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC +
841 tv.tv_nsec / NSEC_PER_MSEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 icmp_param.data.times[2] = icmp_param.data.times[1];
843 if (skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4))
844 BUG();
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300845 icmp_param.data.icmph = *icmp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY;
847 icmp_param.data.icmph.code = 0;
848 icmp_param.skb = skb;
849 icmp_param.offset = 0;
850 icmp_param.data_len = 0;
851 icmp_param.head_len = sizeof(struct icmphdr) + 12;
852 icmp_reply(&icmp_param, skb);
853out:
854 return;
855out_err:
Eric Dumazetadf30902009-06-02 05:19:30 +0000856 ICMP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857 goto out;
858}
859
860
861/*
862 * Handle ICMP_ADDRESS_MASK requests. (RFC950)
863 *
864 * RFC1122 (3.2.2.9). A host MUST only send replies to
865 * ADDRESS_MASK requests if it's been configured as an address mask
866 * agent. Receiving a request doesn't constitute implicit permission to
867 * act as one. Of course, implementing this correctly requires (SHOULD)
868 * a way to turn the functionality on and off. Another one for sysctl(),
869 * I guess. -- MS
870 *
871 * RFC1812 (4.3.3.9). A router MUST implement it.
872 * A router SHOULD have switch turning it on/off.
873 * This switch MUST be ON by default.
874 *
875 * Gratuitous replies, zero-source replies are not implemented,
876 * that complies with RFC. DO NOT implement them!!! All the idea
877 * of broadcast addrmask replies as specified in RFC950 is broken.
878 * The problem is that it is not uncommon to have several prefixes
879 * on one physical interface. Moreover, addrmask agent can even be
880 * not aware of existing another prefixes.
881 * If source is zero, addrmask agent cannot choose correct prefix.
882 * Gratuitous mask announcements suffer from the same problem.
883 * RFC1812 explains it, but still allows to use ADDRMASK,
884 * that is pretty silly. --ANK
885 *
886 * All these rules are so bizarre, that I removed kernel addrmask
887 * support at all. It is wrong, it is obsolete, nobody uses it in
888 * any case. --ANK
889 *
890 * Furthermore you can do it with a usermode address agent program
891 * anyway...
892 */
893
894static void icmp_address(struct sk_buff *skb)
895{
896#if 0
897 if (net_ratelimit())
898 printk(KERN_DEBUG "a guy asks for address mask. Who is it?\n");
899#endif
900}
901
902/*
903 * RFC1812 (4.3.3.9). A router SHOULD listen all replies, and complain
904 * loudly if an inconsistency is found.
Eric Dumazetcfa087f2010-06-07 22:34:35 +0000905 * called with rcu_read_lock()
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 */
907
908static void icmp_address_reply(struct sk_buff *skb)
909{
Eric Dumazet511c3f92009-06-02 05:14:27 +0000910 struct rtable *rt = skb_rtable(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 struct net_device *dev = skb->dev;
912 struct in_device *in_dev;
913 struct in_ifaddr *ifa;
914
915 if (skb->len < 4 || !(rt->rt_flags&RTCF_DIRECTSRC))
Eric Dumazetcfa087f2010-06-07 22:34:35 +0000916 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917
Eric Dumazetcfa087f2010-06-07 22:34:35 +0000918 in_dev = __in_dev_get_rcu(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 if (!in_dev)
Eric Dumazetcfa087f2010-06-07 22:34:35 +0000920 return;
921
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922 if (in_dev->ifa_list &&
923 IN_DEV_LOG_MARTIANS(in_dev) &&
924 IN_DEV_FORWARD(in_dev)) {
Al Viroa144ea42006-09-28 18:00:55 -0700925 __be32 _mask, *mp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926
927 mp = skb_header_pointer(skb, 0, sizeof(_mask), &_mask);
Kris Katterjohn09a62662006-01-08 22:24:28 -0800928 BUG_ON(mp == NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929 for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
930 if (*mp == ifa->ifa_mask &&
931 inet_ifa_match(rt->rt_src, ifa))
932 break;
933 }
934 if (!ifa && net_ratelimit()) {
Harvey Harrison673d57e2008-10-31 00:53:57 -0700935 printk(KERN_INFO "Wrong address mask %pI4 from %s/%pI4\n",
936 mp, dev->name, &rt->rt_src);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 }
938 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939}
940
941static void icmp_discard(struct sk_buff *skb)
942{
943}
944
945/*
946 * Deal with incoming ICMP packets.
947 */
948int icmp_rcv(struct sk_buff *skb)
949{
950 struct icmphdr *icmph;
Eric Dumazet511c3f92009-06-02 05:14:27 +0000951 struct rtable *rt = skb_rtable(skb);
Changli Gaod8d1f302010-06-10 23:31:35 -0700952 struct net *net = dev_net(rt->dst.dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953
Herbert Xuaebcf822007-12-12 18:54:16 -0800954 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
Alexey Dobriyandef8b4f2008-10-28 13:24:06 -0700955 struct sec_path *sp = skb_sec_path(skb);
Herbert Xu8b7817f2007-12-12 10:44:43 -0800956 int nh;
957
Alexey Dobriyandef8b4f2008-10-28 13:24:06 -0700958 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
Herbert Xuaebcf822007-12-12 18:54:16 -0800959 XFRM_STATE_ICMP))
960 goto drop;
961
Herbert Xu8b7817f2007-12-12 10:44:43 -0800962 if (!pskb_may_pull(skb, sizeof(*icmph) + sizeof(struct iphdr)))
963 goto drop;
964
965 nh = skb_network_offset(skb);
966 skb_set_network_header(skb, sizeof(*icmph));
967
968 if (!xfrm4_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
969 goto drop;
970
971 skb_set_network_header(skb, nh);
972 }
973
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700974 ICMP_INC_STATS_BH(net, ICMP_MIB_INMSGS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975
976 switch (skb->ip_summed) {
Patrick McHardy84fa7932006-08-29 16:44:56 -0700977 case CHECKSUM_COMPLETE:
Al Virod3bc23e2006-11-14 21:24:49 -0800978 if (!csum_fold(skb->csum))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979 break;
Herbert Xufb286bb2005-11-10 13:01:24 -0800980 /* fall through */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981 case CHECKSUM_NONE:
Herbert Xufb286bb2005-11-10 13:01:24 -0800982 skb->csum = 0;
983 if (__skb_checksum_complete(skb))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985 }
986
Herbert Xu8cf22942008-02-05 03:15:50 -0800987 if (!pskb_pull(skb, sizeof(*icmph)))
988 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300990 icmph = icmp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991
Pavel Emelyanovf66ac032008-07-14 23:04:00 -0700992 ICMPMSGIN_INC_STATS_BH(net, icmph->type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993 /*
994 * 18 is the highest 'known' ICMP type. Anything else is a mystery
995 *
996 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
997 * discarded.
998 */
999 if (icmph->type > NR_ICMP_TYPES)
1000 goto error;
1001
1002
1003 /*
1004 * Parse the ICMP message
1005 */
1006
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09001007 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001008 /*
1009 * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be
1010 * silently ignored (we let user decide with a sysctl).
1011 * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently
1012 * discarded if to broadcast/multicast.
1013 */
Alexey Kuznetsov4c866aa2005-07-08 17:34:46 -07001014 if ((icmph->type == ICMP_ECHO ||
1015 icmph->type == ICMP_TIMESTAMP) &&
Pavel Emelyanovb34a95e2008-03-26 02:00:21 -07001016 net->ipv4.sysctl_icmp_echo_ignore_broadcasts) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017 goto error;
1018 }
1019 if (icmph->type != ICMP_ECHO &&
1020 icmph->type != ICMP_TIMESTAMP &&
1021 icmph->type != ICMP_ADDRESS &&
1022 icmph->type != ICMP_ADDRESSREPLY) {
1023 goto error;
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09001024 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025 }
1026
Linus Torvalds1da177e2005-04-16 15:20:36 -07001027 icmp_pointers[icmph->type].handler(skb);
1028
1029drop:
1030 kfree_skb(skb);
1031 return 0;
1032error:
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -07001033 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034 goto drop;
1035}
1036
1037/*
1038 * This table is the definition of how we handle ICMP.
1039 */
Arjan van de Ven9b5b5cf2005-11-29 16:21:38 -08001040static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041 [ICMP_ECHOREPLY] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042 .handler = icmp_discard,
1043 },
1044 [1] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045 .handler = icmp_discard,
1046 .error = 1,
1047 },
1048 [2] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001049 .handler = icmp_discard,
1050 .error = 1,
1051 },
1052 [ICMP_DEST_UNREACH] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001053 .handler = icmp_unreach,
1054 .error = 1,
1055 },
1056 [ICMP_SOURCE_QUENCH] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001057 .handler = icmp_unreach,
1058 .error = 1,
1059 },
1060 [ICMP_REDIRECT] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061 .handler = icmp_redirect,
1062 .error = 1,
1063 },
1064 [6] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065 .handler = icmp_discard,
1066 .error = 1,
1067 },
1068 [7] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 .handler = icmp_discard,
1070 .error = 1,
1071 },
1072 [ICMP_ECHO] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073 .handler = icmp_echo,
1074 },
1075 [9] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076 .handler = icmp_discard,
1077 .error = 1,
1078 },
1079 [10] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 .handler = icmp_discard,
1081 .error = 1,
1082 },
1083 [ICMP_TIME_EXCEEDED] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084 .handler = icmp_unreach,
1085 .error = 1,
1086 },
1087 [ICMP_PARAMETERPROB] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 .handler = icmp_unreach,
1089 .error = 1,
1090 },
1091 [ICMP_TIMESTAMP] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 .handler = icmp_timestamp,
1093 },
1094 [ICMP_TIMESTAMPREPLY] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095 .handler = icmp_discard,
1096 },
1097 [ICMP_INFO_REQUEST] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 .handler = icmp_discard,
1099 },
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09001100 [ICMP_INFO_REPLY] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101 .handler = icmp_discard,
1102 },
1103 [ICMP_ADDRESS] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001104 .handler = icmp_address,
1105 },
1106 [ICMP_ADDRESSREPLY] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107 .handler = icmp_address_reply,
1108 },
1109};
1110
Denis V. Lunev4a6ad7a2008-02-29 11:19:58 -08001111static void __net_exit icmp_sk_exit(struct net *net)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113 int i;
1114
Denis V. Lunev5c8cafd2008-02-29 11:19:22 -08001115 for_each_possible_cpu(i)
Denis V. Lunevc1e98942008-04-03 14:29:00 -07001116 inet_ctl_sock_destroy(net->ipv4.icmp_sk[i]);
Denis V. Lunev4a6ad7a2008-02-29 11:19:58 -08001117 kfree(net->ipv4.icmp_sk);
1118 net->ipv4.icmp_sk = NULL;
Denis V. Luneva5710d62008-02-29 11:14:50 -08001119}
1120
Adrian Bunk263173a2008-04-21 02:31:23 -07001121static int __net_init icmp_sk_init(struct net *net)
Denis V. Luneva5710d62008-02-29 11:14:50 -08001122{
Denis V. Luneva5710d62008-02-29 11:14:50 -08001123 int i, err;
1124
Denis V. Lunev4a6ad7a2008-02-29 11:19:58 -08001125 net->ipv4.icmp_sk =
1126 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
1127 if (net->ipv4.icmp_sk == NULL)
Denis V. Lunev79c91152008-02-29 11:17:11 -08001128 return -ENOMEM;
1129
Denis V. Luneva5710d62008-02-29 11:14:50 -08001130 for_each_possible_cpu(i) {
Denis V. Lunev1e3cf682008-02-29 11:15:42 -08001131 struct sock *sk;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132
Denis V. Lunevc1e98942008-04-03 14:29:00 -07001133 err = inet_ctl_sock_create(&sk, PF_INET,
1134 SOCK_RAW, IPPROTO_ICMP, net);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135 if (err < 0)
Denis V. Luneva5710d62008-02-29 11:14:50 -08001136 goto fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137
Denis V. Lunevc1e98942008-04-03 14:29:00 -07001138 net->ipv4.icmp_sk[i] = sk;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139
1140 /* Enough space for 2 64K ICMP packets, including
1141 * sk_buff struct overhead.
1142 */
Denis V. Lunev1e3cf682008-02-29 11:15:42 -08001143 sk->sk_sndbuf =
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144 (2 * ((64 * 1024) + sizeof(struct sk_buff)));
1145
Eric Dumazetb3a5b6c2009-09-24 12:16:51 +00001146 /*
1147 * Speedup sock_wfree()
1148 */
1149 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
Denis V. Lunevc1e98942008-04-03 14:29:00 -07001150 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DONT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 }
Pavel Emelyanova24022e2008-03-26 01:55:37 -07001152
1153 /* Control parameters for ECHO replies. */
1154 net->ipv4.sysctl_icmp_echo_ignore_all = 0;
1155 net->ipv4.sysctl_icmp_echo_ignore_broadcasts = 1;
1156
1157 /* Control parameter - ignore bogus broadcast responses? */
1158 net->ipv4.sysctl_icmp_ignore_bogus_error_responses = 1;
1159
1160 /*
1161 * Configurable global rate limit.
1162 *
1163 * ratelimit defines tokens/packet consumed for dst->rate_token
1164 * bucket ratemask defines which icmp types are ratelimited by
1165 * setting it's bit position.
1166 *
1167 * default:
1168 * dest unreachable (3), source quench (4),
1169 * time exceeded (11), parameter problem (12)
1170 */
1171
1172 net->ipv4.sysctl_icmp_ratelimit = 1 * HZ;
1173 net->ipv4.sysctl_icmp_ratemask = 0x1818;
1174 net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr = 0;
1175
Denis V. Luneva5710d62008-02-29 11:14:50 -08001176 return 0;
1177
1178fail:
Denis V. Lunev1d1c8d12008-02-29 14:15:19 -08001179 for_each_possible_cpu(i)
Denis V. Lunevc1e98942008-04-03 14:29:00 -07001180 inet_ctl_sock_destroy(net->ipv4.icmp_sk[i]);
Denis V. Lunev1d1c8d12008-02-29 14:15:19 -08001181 kfree(net->ipv4.icmp_sk);
Denis V. Luneva5710d62008-02-29 11:14:50 -08001182 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001183}
1184
Denis V. Lunev4a6ad7a2008-02-29 11:19:58 -08001185static struct pernet_operations __net_initdata icmp_sk_ops = {
1186 .init = icmp_sk_init,
1187 .exit = icmp_sk_exit,
1188};
1189
1190int __init icmp_init(void)
1191{
Eric W. Biederman959d2722009-02-22 00:09:14 -08001192 return register_pernet_subsys(&icmp_sk_ops);
Denis V. Lunev4a6ad7a2008-02-29 11:19:58 -08001193}