]> bbs.cooldavid.org Git - net-next-2.6.git/blame - net/ipv4/icmp.c
git://bbs.cooldavid.org / net-next-2.6.git / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
[IPV4]: Fix "ipOutNoRoutes" counter error for TCP and UDP
[net-next-2.6.git] / net / ipv4 / icmp.c
CommitLineData
1da177e4
LT		 1/*
2 * NET3: Implementation of the ICMP protocol layer.
3 *
4 * Alan Cox, <alan@redhat.com>
5 *
6 * Version: $Id: icmp.c,v 1.85 2002/02/01 22:01:03 davem Exp $
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 *
13 * Some of the function names and the icmp unreach table for this
14 * module were derived from [icmp.c 1.0.11 06/02/93] by
15 * Ross Biro, Fred N. van Kempen, Mark Evans, Alan Cox, Gerhard Koerting.
16 * Other than that this module is a complete rewrite.
17 *
18 * Fixes:
19 * Clemens Fruhwirth : introduce global icmp rate limiting
20 * with icmp type masking ability instead
21 * of broken per type icmp timeouts.
22 * Mike Shaver : RFC1122 checks.
23 * Alan Cox : Multicast ping reply as self.
24 * Alan Cox : Fix atomicity lockup in ip_build_xmit
25 * call.
26 * Alan Cox : Added 216,128 byte paths to the MTU
27 * code.
28 * Martin Mares : RFC1812 checks.
29 * Martin Mares : Can be configured to follow redirects
30 * if acting as a router _without_ a
31 * routing protocol (RFC 1812).
32 * Martin Mares : Echo requests may be configured to
33 * be ignored (RFC 1812).
34 * Martin Mares : Limitation of ICMP error message
35 * transmit rate (RFC 1812).
36 * Martin Mares : TOS and Precedence set correctly
37 * (RFC 1812).
38 * Martin Mares : Now copying as much data from the
39 * original packet as we can without
40 * exceeding 576 bytes (RFC 1812).
41 * Willy Konynenberg : Transparent proxying support.
42 * Keith Owens : RFC1191 correction for 4.2BSD based
43 * path MTU bug.
44 * Thomas Quinot : ICMP Dest Unreach codes up to 15 are
45 * valid (RFC 1812).
46 * Andi Kleen : Check all packet lengths properly
47 * and moved all kfree_skb() up to
48 * icmp_rcv.
49 * Andi Kleen : Move the rate limit bookkeeping
50 * into the dest entry and use a token
51 * bucket filter (thanks to ANK). Make
52 * the rates sysctl configurable.
53 * Yu Tianli : Fixed two ugly bugs in icmp_send
54 * - IP option length was accounted wrongly
55 * - ICMP header length was not accounted
56 * at all.
57 * Tristan Greaves : Added sysctl option to ignore bogus
58 * broadcast responses from broken routers.
59 *
60 * To Fix:
61 *
62 * - Should use skb_pull() instead of all the manual checking.
63 * This would also greatly simply some upper layer error handlers. --AK
64 *
65 */
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>
79#include <net/snmp.h>
80#include <net/ip.h>
81#include <net/route.h>
82#include <net/protocol.h>
83#include <net/icmp.h>
84#include <net/tcp.h>
85#include <net/udp.h>
86#include <net/raw.h>
87#include <linux/skbuff.h>
88#include <net/sock.h>
89#include <linux/errno.h>
90#include <linux/timer.h>
91#include <linux/init.h>
92#include <asm/system.h>
93#include <asm/uaccess.h>
94#include <net/checksum.h>
95
96/*
97 * Build xmit assembly blocks
98 */
99
100struct icmp_bxm {
101 struct sk_buff *skb;
102 int offset;
103 int data_len;
104
105 struct {
106 struct icmphdr icmph;
b03d73e3 107 __be32 times[3];
1da177e4
LT		 108 } data;
109 int head_len;
110 struct ip_options replyopts;
111 unsigned char optbuf[40];
112};
113
114/*
115 * Statistics
116 */
ba89966c 117DEFINE_SNMP_STAT(struct icmp_mib, icmp_statistics) __read_mostly;
1da177e4
LT		 118
119/* An array of errno for error messages from dest unreach. */
120/* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
121
122struct icmp_err icmp_err_convert[] = {
123 {
124 .errno = ENETUNREACH, /* ICMP_NET_UNREACH */
125 .fatal = 0,
126 },
127 {
128 .errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */
129 .fatal = 0,
130 },
131 {
132 .errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */,
133 .fatal = 1,
134 },
135 {
136 .errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */
137 .fatal = 1,
138 },
139 {
140 .errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */
141 .fatal = 0,
142 },
143 {
144 .errno = EOPNOTSUPP, /* ICMP_SR_FAILED */
145 .fatal = 0,
146 },
147 {
148 .errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */
149 .fatal = 1,
150 },
151 {
152 .errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */
153 .fatal = 1,
154 },
155 {
156 .errno = ENONET, /* ICMP_HOST_ISOLATED */
157 .fatal = 1,
158 },
159 {
160 .errno = ENETUNREACH, /* ICMP_NET_ANO */
161 .fatal = 1,
162 },
163 {
164 .errno = EHOSTUNREACH, /* ICMP_HOST_ANO */
165 .fatal = 1,
166 },
167 {
168 .errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */
169 .fatal = 0,
170 },
171 {
172 .errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */
173 .fatal = 0,
174 },
175 {
176 .errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */
177 .fatal = 1,
178 },
179 {
180 .errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */
181 .fatal = 1,
182 },
183 {
184 .errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */
185 .fatal = 1,
186 },
187};
188
189/* Control parameters for ECHO replies. */
ab32ea5d
BH		 190int sysctl_icmp_echo_ignore_all __read_mostly;
191int sysctl_icmp_echo_ignore_broadcasts __read_mostly = 1;
1da177e4
LT		 192
193/* Control parameter - ignore bogus broadcast responses? */
ab32ea5d 194int sysctl_icmp_ignore_bogus_error_responses __read_mostly = 1;
1da177e4
LT		 195
196/*
197 * Configurable global rate limit.
198 *
199 * ratelimit defines tokens/packet consumed for dst->rate_token bucket
200 * ratemask defines which icmp types are ratelimited by setting
201 * it's bit position.
202 *
203 * default:
204 * dest unreachable (3), source quench (4),
205 * time exceeded (11), parameter problem (12)
206 */
207
ab32ea5d
BH		 208int sysctl_icmp_ratelimit __read_mostly = 1 * HZ;
209int sysctl_icmp_ratemask __read_mostly = 0x1818;
210int sysctl_icmp_errors_use_inbound_ifaddr __read_mostly;
1da177e4
LT		 211
212/*
213 * ICMP control array. This specifies what to do with each ICMP.
214 */
215
216struct icmp_control {
217 int output_entry; /* Field for increment on output */
218 int input_entry; /* Field for increment on input */
219 void (*handler)(struct sk_buff *skb);
220 short error; /* This ICMP is classed as an error message */
221};
222
9b5b5cff 223static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
1da177e4
LT		 224
225/*
226 * The ICMP socket(s). This is the most convenient way to flow control
227 * our ICMP output as well as maintain a clean interface throughout
228 * all layers. All Socketless IP sends will soon be gone.
229 *
230 * On SMP we have one ICMP socket per-cpu.
231 */
232static DEFINE_PER_CPU(struct socket *, __icmp_socket) = NULL;
233#define icmp_socket __get_cpu_var(__icmp_socket)
234
235static __inline__ int icmp_xmit_lock(void)
236{
237 local_bh_disable();
238
239 if (unlikely(!spin_trylock(&icmp_socket->sk->sk_lock.slock))) {
240 /* This can happen if the output path signals a
241 * dst_link_failure() for an outgoing ICMP packet.
242 */
243 local_bh_enable();
244 return 1;
245 }
246 return 0;
247}
248
249static void icmp_xmit_unlock(void)
250{
251 spin_unlock_bh(&icmp_socket->sk->sk_lock.slock);
252}
253
254/*
255 * Send an ICMP frame.
256 */
257
258/*
259 * Check transmit rate limitation for given message.
260 * The rate information is held in the destination cache now.
261 * This function is generic and could be used for other purposes
262 * too. It uses a Token bucket filter as suggested by Alexey Kuznetsov.
263 *
264 * Note that the same dst_entry fields are modified by functions in
265 * route.c too, but these work for packet destinations while xrlim_allow
266 * works for icmp destinations. This means the rate limiting information
267 * for one "ip object" is shared - and these ICMPs are twice limited:
268 * by source and by destination.
269 *
270 * RFC 1812: 4.3.2.8 SHOULD be able to limit error message rate
271 * SHOULD allow setting of rate limits
272 *
273 * Shared between ICMPv4 and ICMPv6.
274 */
275#define XRLIM_BURST_FACTOR 6
276int xrlim_allow(struct dst_entry *dst, int timeout)
277{
278 unsigned long now;
279 int rc = 0;
280
281 now = jiffies;
282 dst->rate_tokens += now - dst->rate_last;
283 dst->rate_last = now;
284 if (dst->rate_tokens > XRLIM_BURST_FACTOR * timeout)
285 dst->rate_tokens = XRLIM_BURST_FACTOR * timeout;
286 if (dst->rate_tokens >= timeout) {
287 dst->rate_tokens -= timeout;
288 rc = 1;
289 }
290 return rc;
291}
292
293static inline int icmpv4_xrlim_allow(struct rtable *rt, int type, int code)
294{
295 struct dst_entry *dst = &rt->u.dst;
296 int rc = 1;
297
298 if (type > NR_ICMP_TYPES)
299 goto out;
300
301 /* Don't limit PMTU discovery. */
302 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
303 goto out;
304
305 /* No rate limit on loopback */
306 if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
e905a9ed 307 goto out;
1da177e4
LT		 308
309 /* Limit if icmp type is enabled in ratemask. */
310 if ((1 << type) & sysctl_icmp_ratemask)
311 rc = xrlim_allow(dst, sysctl_icmp_ratelimit);
312out:
313 return rc;
314}
315
316/*
317 * Maintain the counters used in the SNMP statistics for outgoing ICMP
318 */
319static void icmp_out_count(int type)
320{
321 if (type <= NR_ICMP_TYPES) {
322 ICMP_INC_STATS(icmp_pointers[type].output_entry);
323 ICMP_INC_STATS(ICMP_MIB_OUTMSGS);
324 }
325}
326
327/*
328 * Checksum each fragment, and on the first include the headers and final
329 * checksum.
330 */
331static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
332 struct sk_buff *skb)
333{
334 struct icmp_bxm *icmp_param = (struct icmp_bxm *)from;
5f92a738 335 __wsum csum;
1da177e4
LT		 336
337 csum = skb_copy_and_csum_bits(icmp_param->skb,
338 icmp_param->offset + offset,
339 to, len, 0);
340
341 skb->csum = csum_block_add(skb->csum, csum, odd);
342 if (icmp_pointers[icmp_param->data.icmph.type].error)
343 nf_ct_attach(skb, icmp_param->skb);
344 return 0;
345}
346
347static void icmp_push_reply(struct icmp_bxm *icmp_param,
348 struct ipcm_cookie *ipc, struct rtable *rt)
349{
350 struct sk_buff *skb;
351
cb94c62c 352 if (ip_append_data(icmp_socket->sk, icmp_glue_bits, icmp_param,
e905a9ed
YH		 353 icmp_param->data_len+icmp_param->head_len,
354 icmp_param->head_len,
355 ipc, rt, MSG_DONTWAIT) < 0)
cb94c62c
PM		 356 ip_flush_pending_frames(icmp_socket->sk);
357 else if ((skb = skb_peek(&icmp_socket->sk->sk_write_queue)) != NULL) {
88c7664f 358 struct icmphdr *icmph = icmp_hdr(skb);
d3bc23e7 359 __wsum csum = 0;
1da177e4
LT		 360 struct sk_buff *skb1;
361
362 skb_queue_walk(&icmp_socket->sk->sk_write_queue, skb1) {
363 csum = csum_add(csum, skb1->csum);
364 }
365 csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
366 (char *)icmph,
367 icmp_param->head_len, csum);
368 icmph->checksum = csum_fold(csum);
369 skb->ip_summed = CHECKSUM_NONE;
370 ip_push_pending_frames(icmp_socket->sk);
371 }
372}
373
374/*
375 * Driving logic for building and sending ICMP messages.
376 */
377
378static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
379{
380 struct sock *sk = icmp_socket->sk;
381 struct inet_sock *inet = inet_sk(sk);
382 struct ipcm_cookie ipc;
383 struct rtable *rt = (struct rtable *)skb->dst;
3ca3c68e 384 __be32 daddr;
1da177e4
LT		 385
386 if (ip_options_echo(&icmp_param->replyopts, skb))
f00c401b 387 return;
1da177e4
LT		 388
389 if (icmp_xmit_lock())
390 return;
391
392 icmp_param->data.icmph.checksum = 0;
393 icmp_out_count(icmp_param->data.icmph.type);
394
eddc9ec5 395 inet->tos = ip_hdr(skb)->tos;
1da177e4
LT		 396 daddr = ipc.addr = rt->rt_src;
397 ipc.opt = NULL;
398 if (icmp_param->replyopts.optlen) {
399 ipc.opt = &icmp_param->replyopts;
400 if (ipc.opt->srr)
401 daddr = icmp_param->replyopts.faddr;
402 }
403 {
404 struct flowi fl = { .nl_u = { .ip4_u =
405 { .daddr = daddr,
406 .saddr = rt->rt_spec_dst,
eddc9ec5 407 .tos = RT_TOS(ip_hdr(skb)->tos) } },
1da177e4 408 .proto = IPPROTO_ICMP };
beb8d13b 409 security_skb_classify_flow(skb, &fl);
1da177e4
LT		 410 if (ip_route_output_key(&rt, &fl))
411 goto out_unlock;
412 }
413 if (icmpv4_xrlim_allow(rt, icmp_param->data.icmph.type,
414 icmp_param->data.icmph.code))
415 icmp_push_reply(icmp_param, &ipc, rt);
416 ip_rt_put(rt);
417out_unlock:
418 icmp_xmit_unlock();
1da177e4
LT		 419}
420
421
422/*
423 * Send an ICMP message in response to a situation
424 *
425 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
426 * MAY send more (we do).
427 * MUST NOT change this header information.
428 * MUST NOT reply to a multicast/broadcast IP address.
429 * MUST NOT reply to a multicast/broadcast MAC address.
430 * MUST reply to only the first fragment.
431 */
432
e4883014 433void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
1da177e4
LT		 434{
435 struct iphdr *iph;
436 int room;
437 struct icmp_bxm icmp_param;
438 struct rtable *rt = (struct rtable *)skb_in->dst;
439 struct ipcm_cookie ipc;
a61ced5d 440 __be32 saddr;
1da177e4
LT		 441 u8 tos;
442
443 if (!rt)
444 goto out;
445
446 /*
447 * Find the original header. It is expected to be valid, of course.
448 * Check this, icmp_send is called from the most obscure devices
449 * sometimes.
450 */
eddc9ec5 451 iph = ip_hdr(skb_in);
1da177e4 452
27a884dc
ACM		 453 if ((u8 *)iph < skb_in->head ||
454 (skb_in->network_header + sizeof(*iph)) > skb_in->tail)
1da177e4
LT		 455 goto out;
456
457 /*
458 * No replies to physical multicast/broadcast
459 */
460 if (skb_in->pkt_type != PACKET_HOST)
461 goto out;
462
463 /*
464 * Now check at the protocol level
465 */
466 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
467 goto out;
468
469 /*
470 * Only reply to fragment 0. We byte re-order the constant
471 * mask for efficiency.
472 */
473 if (iph->frag_off & htons(IP_OFFSET))
474 goto out;
475
476 /*
477 * If we send an ICMP error to an ICMP error a mess would result..
478 */
479 if (icmp_pointers[type].error) {
480 /*
481 * We are an error, check if we are replying to an
482 * ICMP error
483 */
484 if (iph->protocol == IPPROTO_ICMP) {
485 u8 _inner_type, *itp;
486
487 itp = skb_header_pointer(skb_in,
d56f90a7 488 skb_network_header(skb_in) +
1da177e4
LT		 489 (iph->ihl << 2) +
490 offsetof(struct icmphdr,
491 type) -
492 skb_in->data,
493 sizeof(_inner_type),
494 &_inner_type);
495 if (itp == NULL)
496 goto out;
497
498 /*
499 * Assume any unknown ICMP type is an error. This
500 * isn't specified by the RFC, but think about it..
501 */
502 if (*itp > NR_ICMP_TYPES ||
503 icmp_pointers[*itp].error)
504 goto out;
505 }
506 }
507
508 if (icmp_xmit_lock())
509 return;
510
511 /*
512 * Construct source address and options.
513 */
514
515 saddr = iph->daddr;
1c2fb7f9 516 if (!(rt->rt_flags & RTCF_LOCAL)) {
d8cf2728
PM		 517 /* This is broken, skb_in->dev points to the outgoing device
518 * after the packet passes through ip_output().
519 */
520 if (skb_in->dev && sysctl_icmp_errors_use_inbound_ifaddr)
1c2fb7f9
S		 521 saddr = inet_select_addr(skb_in->dev, 0, RT_SCOPE_LINK);
522 else
523 saddr = 0;
524 }
1da177e4
LT		 525
526 tos = icmp_pointers[type].error ? ((iph->tos & IPTOS_TOS_MASK) |
527 IPTOS_PREC_INTERNETCONTROL) :
528 iph->tos;
529
530 if (ip_options_echo(&icmp_param.replyopts, skb_in))
fa60cf7f 531 goto out_unlock;
1da177e4
LT		 532
533
534 /*
535 * Prepare data for ICMP header.
536 */
537
538 icmp_param.data.icmph.type = type;
539 icmp_param.data.icmph.code = code;
540 icmp_param.data.icmph.un.gateway = info;
541 icmp_param.data.icmph.checksum = 0;
542 icmp_param.skb = skb_in;
d56f90a7 543 icmp_param.offset = skb_network_offset(skb_in);
1da177e4
LT		 544 icmp_out_count(icmp_param.data.icmph.type);
545 inet_sk(icmp_socket->sk)->tos = tos;
546 ipc.addr = iph->saddr;
547 ipc.opt = &icmp_param.replyopts;
548
549 {
550 struct flowi fl = {
551 .nl_u = {
552 .ip4_u = {
553 .daddr = icmp_param.replyopts.srr ?
554 icmp_param.replyopts.faddr :
555 iph->saddr,
556 .saddr = saddr,
557 .tos = RT_TOS(tos)
558 }
559 },
560 .proto = IPPROTO_ICMP,
561 .uli_u = {
562 .icmpt = {
563 .type = type,
564 .code = code
565 }
566 }
567 };
beb8d13b 568 security_skb_classify_flow(skb_in, &fl);
1da177e4
LT		 569 if (ip_route_output_key(&rt, &fl))
570 goto out_unlock;
571 }
572
573 if (!icmpv4_xrlim_allow(rt, type, code))
574 goto ende;
575
576 /* RFC says return as much as we can without exceeding 576 bytes. */
577
578 room = dst_mtu(&rt->u.dst);
579 if (room > 576)
580 room = 576;
581 room -= sizeof(struct iphdr) + icmp_param.replyopts.optlen;
582 room -= sizeof(struct icmphdr);
583
584 icmp_param.data_len = skb_in->len - icmp_param.offset;
585 if (icmp_param.data_len > room)
586 icmp_param.data_len = room;
587 icmp_param.head_len = sizeof(struct icmphdr);
588
589 icmp_push_reply(&icmp_param, &ipc, rt);
590ende:
591 ip_rt_put(rt);
592out_unlock:
593 icmp_xmit_unlock();
594out:;
595}
596
597
598/*
599 * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEED, and ICMP_QUENCH.
600 */
601
602static void icmp_unreach(struct sk_buff *skb)
603{
604 struct iphdr *iph;
605 struct icmphdr *icmph;
606 int hash, protocol;
607 struct net_protocol *ipprot;
608 struct sock *raw_sk;
609 u32 info = 0;
610
611 /*
612 * Incomplete header ?
613 * Only checks for the IP header, there should be an
614 * additional check for longer headers in upper levels.
615 */
616
617 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
618 goto out_err;
619
88c7664f 620 icmph = icmp_hdr(skb);
1da177e4
LT		 621 iph = (struct iphdr *)skb->data;
622
623 if (iph->ihl < 5) /* Mangled header, drop. */
624 goto out_err;
625
626 if (icmph->type == ICMP_DEST_UNREACH) {
627 switch (icmph->code & 15) {
628 case ICMP_NET_UNREACH:
629 case ICMP_HOST_UNREACH:
630 case ICMP_PROT_UNREACH:
631 case ICMP_PORT_UNREACH:
632 break;
633 case ICMP_FRAG_NEEDED:
634 if (ipv4_config.no_pmtu_disc) {
64ce2073 635 LIMIT_NETDEBUG(KERN_INFO "ICMP: %u.%u.%u.%u: "
1da177e4
LT		 636 "fragmentation needed "
637 "and DF set.\n",
64ce2073 638 NIPQUAD(iph->daddr));
1da177e4
LT		 639 } else {
640 info = ip_rt_frag_needed(iph,
641 ntohs(icmph->un.frag.mtu));
642 if (!info)
643 goto out;
644 }
645 break;
646 case ICMP_SR_FAILED:
64ce2073 647 LIMIT_NETDEBUG(KERN_INFO "ICMP: %u.%u.%u.%u: Source "
1da177e4 648 "Route Failed.\n",
64ce2073 649 NIPQUAD(iph->daddr));
1da177e4
LT		 650 break;
651 default:
652 break;
653 }
654 if (icmph->code > NR_ICMP_UNREACH)
655 goto out;
656 } else if (icmph->type == ICMP_PARAMETERPROB)
657 info = ntohl(icmph->un.gateway) >> 24;
658
659 /*
660 * Throw it at our lower layers
661 *
662 * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed
663 * header.
664 * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
665 * transport layer.
666 * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
667 * transport layer.
668 */
669
670 /*
671 * Check the other end isnt violating RFC 1122. Some routers send
672 * bogus responses to broadcast frames. If you see this message
673 * first check your netmask matches at both ends, if it does then
674 * get the other vendor to fix their kit.
675 */
676
677 if (!sysctl_icmp_ignore_bogus_error_responses &&
678 inet_addr_type(iph->daddr) == RTN_BROADCAST) {
679 if (net_ratelimit())
680 printk(KERN_WARNING "%u.%u.%u.%u sent an invalid ICMP "
681 "type %u, code %u "
682 "error to a broadcast: %u.%u.%u.%u on %s\n",
eddc9ec5 683 NIPQUAD(ip_hdr(skb)->saddr),
1da177e4
LT		 684 icmph->type, icmph->code,
685 NIPQUAD(iph->daddr),
686 skb->dev->name);
687 goto out;
688 }
689
690 /* Checkin full IP header plus 8 bytes of protocol to
691 * avoid additional coding at protocol handlers.
692 */
693 if (!pskb_may_pull(skb, iph->ihl * 4 + 8))
694 goto out;
695
696 iph = (struct iphdr *)skb->data;
697 protocol = iph->protocol;
698
699 /*
700 * Deliver ICMP message to raw sockets. Pretty useless feature?
701 */
702
703 /* Note: See raw.c and net/raw.h, RAWV4_HTABLE_SIZE==MAX_INET_PROTOS */
704 hash = protocol & (MAX_INET_PROTOS - 1);
705 read_lock(&raw_v4_lock);
706 if ((raw_sk = sk_head(&raw_v4_htable[hash])) != NULL) {
707 while ((raw_sk = __raw_v4_lookup(raw_sk, protocol, iph->daddr,
708 iph->saddr,
709 skb->dev->ifindex)) != NULL) {
710 raw_err(raw_sk, skb, info);
711 raw_sk = sk_next(raw_sk);
712 iph = (struct iphdr *)skb->data;
713 }
714 }
715 read_unlock(&raw_v4_lock);
716
717 rcu_read_lock();
718 ipprot = rcu_dereference(inet_protos[hash]);
719 if (ipprot && ipprot->err_handler)
720 ipprot->err_handler(skb, info);
721 rcu_read_unlock();
722
723out:
724 return;
725out_err:
726 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
727 goto out;
728}
729
730
731/*
732 * Handle ICMP_REDIRECT.
733 */
734
735static void icmp_redirect(struct sk_buff *skb)
736{
737 struct iphdr *iph;
1da177e4
LT		 738
739 if (skb->len < sizeof(struct iphdr))
740 goto out_err;
741
742 /*
743 * Get the copied header of the packet that caused the redirect
744 */
745 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
746 goto out;
747
748 iph = (struct iphdr *)skb->data;
1da177e4 749
88c7664f 750 switch (icmp_hdr(skb)->code & 7) {
1da177e4
LT		 751 case ICMP_REDIR_NET:
752 case ICMP_REDIR_NETTOS:
753 /*
754 * As per RFC recommendations now handle it as a host redirect.
755 */
756 case ICMP_REDIR_HOST:
757 case ICMP_REDIR_HOSTTOS:
eddc9ec5 758 ip_rt_redirect(ip_hdr(skb)->saddr, iph->daddr,
88c7664f 759 icmp_hdr(skb)->un.gateway,
cef2685e 760 iph->saddr, skb->dev);
1da177e4 761 break;
e905a9ed 762 }
1da177e4
LT		 763out:
764 return;
765out_err:
766 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
767 goto out;
768}
769
770/*
771 * Handle ICMP_ECHO ("ping") requests.
772 *
773 * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
774 * requests.
775 * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be
776 * included in the reply.
777 * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring
778 * echo requests, MUST have default=NOT.
779 * See also WRT handling of options once they are done and working.
780 */
781
782static void icmp_echo(struct sk_buff *skb)
783{
784 if (!sysctl_icmp_echo_ignore_all) {
785 struct icmp_bxm icmp_param;
786
88c7664f 787 icmp_param.data.icmph = *icmp_hdr(skb);
1da177e4
LT		 788 icmp_param.data.icmph.type = ICMP_ECHOREPLY;
789 icmp_param.skb = skb;
790 icmp_param.offset = 0;
791 icmp_param.data_len = skb->len;
792 icmp_param.head_len = sizeof(struct icmphdr);
793 icmp_reply(&icmp_param, skb);
794 }
795}
796
797/*
798 * Handle ICMP Timestamp requests.
799 * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests.
800 * SHOULD be in the kernel for minimum random latency.
801 * MUST be accurate to a few minutes.
802 * MUST be updated at least at 15Hz.
803 */
804static void icmp_timestamp(struct sk_buff *skb)
805{
806 struct timeval tv;
807 struct icmp_bxm icmp_param;
808 /*
809 * Too short.
810 */
811 if (skb->len < 4)
812 goto out_err;
813
814 /*
815 * Fill in the current time as ms since midnight UT:
816 */
817 do_gettimeofday(&tv);
818 icmp_param.data.times[1] = htonl((tv.tv_sec % 86400) * 1000 +
819 tv.tv_usec / 1000);
820 icmp_param.data.times[2] = icmp_param.data.times[1];
821 if (skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4))
822 BUG();
88c7664f 823 icmp_param.data.icmph = *icmp_hdr(skb);
1da177e4
LT		 824 icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY;
825 icmp_param.data.icmph.code = 0;
826 icmp_param.skb = skb;
827 icmp_param.offset = 0;
828 icmp_param.data_len = 0;
829 icmp_param.head_len = sizeof(struct icmphdr) + 12;
830 icmp_reply(&icmp_param, skb);
831out:
832 return;
833out_err:
834 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
835 goto out;
836}
837
838
839/*
840 * Handle ICMP_ADDRESS_MASK requests. (RFC950)
841 *
842 * RFC1122 (3.2.2.9). A host MUST only send replies to
843 * ADDRESS_MASK requests if it's been configured as an address mask
844 * agent. Receiving a request doesn't constitute implicit permission to
845 * act as one. Of course, implementing this correctly requires (SHOULD)
846 * a way to turn the functionality on and off. Another one for sysctl(),
847 * I guess. -- MS
848 *
849 * RFC1812 (4.3.3.9). A router MUST implement it.
850 * A router SHOULD have switch turning it on/off.
851 * This switch MUST be ON by default.
852 *
853 * Gratuitous replies, zero-source replies are not implemented,
854 * that complies with RFC. DO NOT implement them!!! All the idea
855 * of broadcast addrmask replies as specified in RFC950 is broken.
856 * The problem is that it is not uncommon to have several prefixes
857 * on one physical interface. Moreover, addrmask agent can even be
858 * not aware of existing another prefixes.
859 * If source is zero, addrmask agent cannot choose correct prefix.
860 * Gratuitous mask announcements suffer from the same problem.
861 * RFC1812 explains it, but still allows to use ADDRMASK,
862 * that is pretty silly. --ANK
863 *
864 * All these rules are so bizarre, that I removed kernel addrmask
865 * support at all. It is wrong, it is obsolete, nobody uses it in
866 * any case. --ANK
867 *
868 * Furthermore you can do it with a usermode address agent program
869 * anyway...
870 */
871
872static void icmp_address(struct sk_buff *skb)
873{
874#if 0
875 if (net_ratelimit())
876 printk(KERN_DEBUG "a guy asks for address mask. Who is it?\n");
877#endif
878}
879
880/*
881 * RFC1812 (4.3.3.9). A router SHOULD listen all replies, and complain
882 * loudly if an inconsistency is found.
883 */
884
885static void icmp_address_reply(struct sk_buff *skb)
886{
887 struct rtable *rt = (struct rtable *)skb->dst;
888 struct net_device *dev = skb->dev;
889 struct in_device *in_dev;
890 struct in_ifaddr *ifa;
891
892 if (skb->len < 4 || !(rt->rt_flags&RTCF_DIRECTSRC))
893 goto out;
894
895 in_dev = in_dev_get(dev);
896 if (!in_dev)
897 goto out;
898 rcu_read_lock();
899 if (in_dev->ifa_list &&
900 IN_DEV_LOG_MARTIANS(in_dev) &&
901 IN_DEV_FORWARD(in_dev)) {
a144ea4b 902 __be32 _mask, *mp;
1da177e4
LT		 903
904 mp = skb_header_pointer(skb, 0, sizeof(_mask), &_mask);
09a62660 905 BUG_ON(mp == NULL);
1da177e4
LT		 906 for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
907 if (*mp == ifa->ifa_mask &&
908 inet_ifa_match(rt->rt_src, ifa))
909 break;
910 }
911 if (!ifa && net_ratelimit()) {
912 printk(KERN_INFO "Wrong address mask %u.%u.%u.%u from "
913 "%s/%u.%u.%u.%u\n",
914 NIPQUAD(*mp), dev->name, NIPQUAD(rt->rt_src));
915 }
916 }
917 rcu_read_unlock();
918 in_dev_put(in_dev);
919out:;
920}
921
922static void icmp_discard(struct sk_buff *skb)
923{
924}
925
926/*
927 * Deal with incoming ICMP packets.
928 */
929int icmp_rcv(struct sk_buff *skb)
930{
931 struct icmphdr *icmph;
932 struct rtable *rt = (struct rtable *)skb->dst;
933
934 ICMP_INC_STATS_BH(ICMP_MIB_INMSGS);
935
936 switch (skb->ip_summed) {
84fa7933 937 case CHECKSUM_COMPLETE:
d3bc23e7 938 if (!csum_fold(skb->csum))
1da177e4 939 break;
fb286bb2 940 /* fall through */
1da177e4 941 case CHECKSUM_NONE:
fb286bb2
HX		 942 skb->csum = 0;
943 if (__skb_checksum_complete(skb))
1da177e4 944 goto error;
1da177e4
LT		 945 }
946
947 if (!pskb_pull(skb, sizeof(struct icmphdr)))
948 goto error;
949
88c7664f 950 icmph = icmp_hdr(skb);
1da177e4
LT		 951
952 /*
953 * 18 is the highest 'known' ICMP type. Anything else is a mystery
954 *
955 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
956 * discarded.
957 */
958 if (icmph->type > NR_ICMP_TYPES)
959 goto error;
960
961
962 /*
963 * Parse the ICMP message
964 */
965
e905a9ed 966 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1da177e4
LT		 967 /*
968 * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be
969 * silently ignored (we let user decide with a sysctl).
970 * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently
971 * discarded if to broadcast/multicast.
972 */
4c866aa7
AK		 973 if ((icmph->type == ICMP_ECHO ||
974 icmph->type == ICMP_TIMESTAMP) &&
1da177e4
LT		 975 sysctl_icmp_echo_ignore_broadcasts) {
976 goto error;
977 }
978 if (icmph->type != ICMP_ECHO &&
979 icmph->type != ICMP_TIMESTAMP &&
980 icmph->type != ICMP_ADDRESS &&
981 icmph->type != ICMP_ADDRESSREPLY) {
982 goto error;
e905a9ed 983 }
1da177e4
LT		 984 }
985
986 ICMP_INC_STATS_BH(icmp_pointers[icmph->type].input_entry);
987 icmp_pointers[icmph->type].handler(skb);
988
989drop:
990 kfree_skb(skb);
991 return 0;
992error:
993 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
994 goto drop;
995}
996
997/*
998 * This table is the definition of how we handle ICMP.
999 */
9b5b5cff 1000static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = {
1da177e4
LT		 1001 [ICMP_ECHOREPLY] = {
1002 .output_entry = ICMP_MIB_OUTECHOREPS,
1003 .input_entry = ICMP_MIB_INECHOREPS,
1004 .handler = icmp_discard,
1005 },
1006 [1] = {
1007 .output_entry = ICMP_MIB_DUMMY,
1008 .input_entry = ICMP_MIB_INERRORS,
1009 .handler = icmp_discard,
1010 .error = 1,
1011 },
1012 [2] = {
1013 .output_entry = ICMP_MIB_DUMMY,
1014 .input_entry = ICMP_MIB_INERRORS,
1015 .handler = icmp_discard,
1016 .error = 1,
1017 },
1018 [ICMP_DEST_UNREACH] = {
1019 .output_entry = ICMP_MIB_OUTDESTUNREACHS,
1020 .input_entry = ICMP_MIB_INDESTUNREACHS,
1021 .handler = icmp_unreach,
1022 .error = 1,
1023 },
1024 [ICMP_SOURCE_QUENCH] = {
1025 .output_entry = ICMP_MIB_OUTSRCQUENCHS,
1026 .input_entry = ICMP_MIB_INSRCQUENCHS,
1027 .handler = icmp_unreach,
1028 .error = 1,
1029 },
1030 [ICMP_REDIRECT] = {
1031 .output_entry = ICMP_MIB_OUTREDIRECTS,
1032 .input_entry = ICMP_MIB_INREDIRECTS,
1033 .handler = icmp_redirect,
1034 .error = 1,
1035 },
1036 [6] = {
1037 .output_entry = ICMP_MIB_DUMMY,
1038 .input_entry = ICMP_MIB_INERRORS,
1039 .handler = icmp_discard,
1040 .error = 1,
1041 },
1042 [7] = {
1043 .output_entry = ICMP_MIB_DUMMY,
1044 .input_entry = ICMP_MIB_INERRORS,
1045 .handler = icmp_discard,
1046 .error = 1,
1047 },
1048 [ICMP_ECHO] = {
1049 .output_entry = ICMP_MIB_OUTECHOS,
1050 .input_entry = ICMP_MIB_INECHOS,
1051 .handler = icmp_echo,
1052 },
1053 [9] = {
1054 .output_entry = ICMP_MIB_DUMMY,
1055 .input_entry = ICMP_MIB_INERRORS,
1056 .handler = icmp_discard,
1057 .error = 1,
1058 },
1059 [10] = {
1060 .output_entry = ICMP_MIB_DUMMY,
1061 .input_entry = ICMP_MIB_INERRORS,
1062 .handler = icmp_discard,
1063 .error = 1,
1064 },
1065 [ICMP_TIME_EXCEEDED] = {
1066 .output_entry = ICMP_MIB_OUTTIMEEXCDS,
1067 .input_entry = ICMP_MIB_INTIMEEXCDS,
1068 .handler = icmp_unreach,
1069 .error = 1,
1070 },
1071 [ICMP_PARAMETERPROB] = {
1072 .output_entry = ICMP_MIB_OUTPARMPROBS,
1073 .input_entry = ICMP_MIB_INPARMPROBS,
1074 .handler = icmp_unreach,
1075 .error = 1,
1076 },
1077 [ICMP_TIMESTAMP] = {
1078 .output_entry = ICMP_MIB_OUTTIMESTAMPS,
1079 .input_entry = ICMP_MIB_INTIMESTAMPS,
1080 .handler = icmp_timestamp,
1081 },
1082 [ICMP_TIMESTAMPREPLY] = {
1083 .output_entry = ICMP_MIB_OUTTIMESTAMPREPS,
1084 .input_entry = ICMP_MIB_INTIMESTAMPREPS,
1085 .handler = icmp_discard,
1086 },
1087 [ICMP_INFO_REQUEST] = {
1088 .output_entry = ICMP_MIB_DUMMY,
1089 .input_entry = ICMP_MIB_DUMMY,
1090 .handler = icmp_discard,
1091 },
e905a9ed 1092 [ICMP_INFO_REPLY] = {
1da177e4
LT		 1093 .output_entry = ICMP_MIB_DUMMY,
1094 .input_entry = ICMP_MIB_DUMMY,
1095 .handler = icmp_discard,
1096 },
1097 [ICMP_ADDRESS] = {
1098 .output_entry = ICMP_MIB_OUTADDRMASKS,
1099 .input_entry = ICMP_MIB_INADDRMASKS,
1100 .handler = icmp_address,
1101 },
1102 [ICMP_ADDRESSREPLY] = {
1103 .output_entry = ICMP_MIB_OUTADDRMASKREPS,
1104 .input_entry = ICMP_MIB_INADDRMASKREPS,
1105 .handler = icmp_address_reply,
1106 },
1107};
1108
1109void __init icmp_init(struct net_proto_family *ops)
1110{
1111 struct inet_sock *inet;
1112 int i;
1113
6f912042 1114 for_each_possible_cpu(i) {
1da177e4
LT		 1115 int err;
1116
1da177e4
LT		 1117 err = sock_create_kern(PF_INET, SOCK_RAW, IPPROTO_ICMP,
1118 &per_cpu(__icmp_socket, i));
1119
1120 if (err < 0)
1121 panic("Failed to create the ICMP control socket.\n");
1122
1123 per_cpu(__icmp_socket, i)->sk->sk_allocation = GFP_ATOMIC;
1124
1125 /* Enough space for 2 64K ICMP packets, including
1126 * sk_buff struct overhead.
1127 */
1128 per_cpu(__icmp_socket, i)->sk->sk_sndbuf =
1129 (2 * ((64 * 1024) + sizeof(struct sk_buff)));
1130
1131 inet = inet_sk(per_cpu(__icmp_socket, i)->sk);
1132 inet->uc_ttl = -1;
1133 inet->pmtudisc = IP_PMTUDISC_DONT;
1134
1135 /* Unhash it so that IP input processing does not even
1136 * see it, we do not wish this socket to see incoming
1137 * packets.
1138 */
1139 per_cpu(__icmp_socket, i)->sk->sk_prot->unhash(per_cpu(__icmp_socket, i)->sk);
1140 }
1141}
1142
1143EXPORT_SYMBOL(icmp_err_convert);
1144EXPORT_SYMBOL(icmp_send);
1145EXPORT_SYMBOL(icmp_statistics);
1146EXPORT_SYMBOL(xrlim_allow);
Clone of davem's net-next-2.6 tree