FreeBSD/Linux Kernel Cross Reference
sys/netinet/ip_icmp.c
1 /* $NetBSD: ip_icmp.c,v 1.105 2006/11/16 01:33:45 christos Exp $ */
2
3 /*
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the project nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 /*-
33 * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
34 * All rights reserved.
35 *
36 * This code is derived from software contributed to The NetBSD Foundation
37 * by Public Access Networks Corporation ("Panix"). It was developed under
38 * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon.
39 *
40 * This code is derived from software contributed to The NetBSD Foundation
41 * by Jason R. Thorpe of Zembu Labs, Inc.
42 *
43 * Redistribution and use in source and binary forms, with or without
44 * modification, are permitted provided that the following conditions
45 * are met:
46 * 1. Redistributions of source code must retain the above copyright
47 * notice, this list of conditions and the following disclaimer.
48 * 2. Redistributions in binary form must reproduce the above copyright
49 * notice, this list of conditions and the following disclaimer in the
50 * documentation and/or other materials provided with the distribution.
51 * 3. All advertising materials mentioning features or use of this software
52 * must display the following acknowledgement:
53 * This product includes software developed by the NetBSD
54 * Foundation, Inc. and its contributors.
55 * 4. Neither the name of The NetBSD Foundation nor the names of its
56 * contributors may be used to endorse or promote products derived
57 * from this software without specific prior written permission.
58 *
59 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
60 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
61 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
62 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
63 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
64 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
65 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
66 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
67 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
68 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
69 * POSSIBILITY OF SUCH DAMAGE.
70 */
71
72 /*
73 * Copyright (c) 1982, 1986, 1988, 1993
74 * The Regents of the University of California. All rights reserved.
75 *
76 * Redistribution and use in source and binary forms, with or without
77 * modification, are permitted provided that the following conditions
78 * are met:
79 * 1. Redistributions of source code must retain the above copyright
80 * notice, this list of conditions and the following disclaimer.
81 * 2. Redistributions in binary form must reproduce the above copyright
82 * notice, this list of conditions and the following disclaimer in the
83 * documentation and/or other materials provided with the distribution.
84 * 3. Neither the name of the University nor the names of its contributors
85 * may be used to endorse or promote products derived from this software
86 * without specific prior written permission.
87 *
88 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
89 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
90 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
91 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
92 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
93 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
94 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
95 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
96 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
97 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
98 * SUCH DAMAGE.
99 *
100 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
101 */
102
103 #include <sys/cdefs.h>
104 __KERNEL_RCSID(0, "$NetBSD: ip_icmp.c,v 1.105 2006/11/16 01:33:45 christos Exp $");
105
106 #include "opt_ipsec.h"
107
108 #include <sys/param.h>
109 #include <sys/systm.h>
110 #include <sys/malloc.h>
111 #include <sys/mbuf.h>
112 #include <sys/protosw.h>
113 #include <sys/socket.h>
114 #include <sys/time.h>
115 #include <sys/kernel.h>
116 #include <sys/syslog.h>
117 #include <sys/sysctl.h>
118
119 #include <net/if.h>
120 #include <net/route.h>
121
122 #include <netinet/in.h>
123 #include <netinet/in_systm.h>
124 #include <netinet/in_var.h>
125 #include <netinet/ip.h>
126 #include <netinet/ip_icmp.h>
127 #include <netinet/ip_var.h>
128 #include <netinet/in_pcb.h>
129 #include <netinet/in_proto.h>
130 #include <netinet/icmp_var.h>
131
132 #ifdef IPSEC
133 #include <netinet6/ipsec.h>
134 #include <netkey/key.h>
135 #endif
136
137 #ifdef FAST_IPSEC
138 #include <netipsec/ipsec.h>
139 #include <netipsec/key.h>
140 #endif /* FAST_IPSEC*/
141
142 #include <machine/stdarg.h>
143
144 /*
145 * ICMP routines: error generation, receive packet processing, and
146 * routines to turnaround packets back to the originator, and
147 * host table maintenance routines.
148 */
149
150 int icmpmaskrepl = 0;
151 #ifdef ICMPPRINTFS
152 int icmpprintfs = 0;
153 #endif
154 int icmpreturndatabytes = 8;
155
156 struct icmpstat icmpstat;
157
158 /*
159 * List of callbacks to notify when Path MTU changes are made.
160 */
161 struct icmp_mtudisc_callback {
162 LIST_ENTRY(icmp_mtudisc_callback) mc_list;
163 void (*mc_func)(struct in_addr);
164 };
165
166 LIST_HEAD(, icmp_mtudisc_callback) icmp_mtudisc_callbacks =
167 LIST_HEAD_INITIALIZER(&icmp_mtudisc_callbacks);
168
169 #if 0
170 static u_int ip_next_mtu(u_int, int);
171 #else
172 /*static*/ u_int ip_next_mtu(u_int, int);
173 #endif
174
175 extern int icmperrppslim;
176 static int icmperrpps_count = 0;
177 static struct timeval icmperrppslim_last;
178 static int icmp_rediraccept = 1;
179 static int icmp_redirtimeout = 600;
180 static struct rttimer_queue *icmp_redirect_timeout_q = NULL;
181
182 static void icmp_mtudisc_timeout(struct rtentry *, struct rttimer *);
183 static void icmp_redirect_timeout(struct rtentry *, struct rttimer *);
184
185 static int icmp_ratelimit(const struct in_addr *, const int, const int);
186
187
188 void
189 icmp_init(void)
190 {
191 /*
192 * This is only useful if the user initializes redirtimeout to
193 * something other than zero.
194 */
195 if (icmp_redirtimeout != 0) {
196 icmp_redirect_timeout_q =
197 rt_timer_queue_create(icmp_redirtimeout);
198 }
199 }
200
201 /*
202 * Register a Path MTU Discovery callback.
203 */
204 void
205 icmp_mtudisc_callback_register(void (*func)(struct in_addr))
206 {
207 struct icmp_mtudisc_callback *mc;
208
209 for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL;
210 mc = LIST_NEXT(mc, mc_list)) {
211 if (mc->mc_func == func)
212 return;
213 }
214
215 mc = malloc(sizeof(*mc), M_PCB, M_NOWAIT);
216 if (mc == NULL)
217 panic("icmp_mtudisc_callback_register");
218
219 mc->mc_func = func;
220 LIST_INSERT_HEAD(&icmp_mtudisc_callbacks, mc, mc_list);
221 }
222
223 /*
224 * Generate an error packet of type error
225 * in response to bad packet ip.
226 */
227 void
228 icmp_error(struct mbuf *n, int type, int code, n_long dest,
229 int destmtu)
230 {
231 struct ip *oip = mtod(n, struct ip *), *nip;
232 unsigned oiplen = oip->ip_hl << 2;
233 struct icmp *icp;
234 struct mbuf *m;
235 struct m_tag *mtag;
236 unsigned icmplen, mblen;
237
238 #ifdef ICMPPRINTFS
239 if (icmpprintfs)
240 printf("icmp_error(%p, type:%d, code:%d)\n", oip, type, code);
241 #endif
242 if (type != ICMP_REDIRECT)
243 icmpstat.icps_error++;
244 /*
245 * Don't send error if the original packet was encrypted.
246 * Don't send error if not the first fragment of message.
247 * Don't error if the old packet protocol was ICMP
248 * error message, only known informational types.
249 */
250 if (n->m_flags & M_DECRYPTED)
251 goto freeit;
252 if (oip->ip_off &~ htons(IP_MF|IP_DF))
253 goto freeit;
254 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
255 n->m_len >= oiplen + ICMP_MINLEN &&
256 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) {
257 icmpstat.icps_oldicmp++;
258 goto freeit;
259 }
260 /* Don't send error in response to a multicast or broadcast packet */
261 if (n->m_flags & (M_BCAST|M_MCAST))
262 goto freeit;
263
264 /*
265 * First, do a rate limitation check.
266 */
267 if (icmp_ratelimit(&oip->ip_src, type, code)) {
268 /* XXX stat */
269 goto freeit;
270 }
271
272 /*
273 * Now, formulate icmp message
274 */
275 icmplen = oiplen + min(icmpreturndatabytes,
276 ntohs(oip->ip_len) - oiplen);
277 /*
278 * Defend against mbuf chains shorter than oip->ip_len - oiplen:
279 */
280 mblen = 0;
281 for (m = n; m && (mblen < icmplen); m = m->m_next)
282 mblen += m->m_len;
283 icmplen = min(mblen, icmplen);
284
285 /*
286 * As we are not required to return everything we have,
287 * we return whatever we can return at ease.
288 *
289 * Note that ICMP datagrams longer than 576 octets are out of spec
290 * according to RFC1812; the limit on icmpreturndatabytes below in
291 * icmp_sysctl will keep things below that limit.
292 */
293
294 KASSERT(ICMP_MINLEN <= MCLBYTES);
295
296 if (icmplen + ICMP_MINLEN > MCLBYTES)
297 icmplen = MCLBYTES - ICMP_MINLEN;
298
299 m = m_gethdr(M_DONTWAIT, MT_HEADER);
300 if (m && (icmplen + ICMP_MINLEN > MHLEN)) {
301 MCLGET(m, M_DONTWAIT);
302 if ((m->m_flags & M_EXT) == 0) {
303 m_freem(m);
304 m = NULL;
305 }
306 }
307 if (m == NULL)
308 goto freeit;
309 MCLAIM(m, n->m_owner);
310 m->m_len = icmplen + ICMP_MINLEN;
311 if ((m->m_flags & M_EXT) == 0)
312 MH_ALIGN(m, m->m_len);
313 icp = mtod(m, struct icmp *);
314 if ((u_int)type > ICMP_MAXTYPE)
315 panic("icmp_error");
316 icmpstat.icps_outhist[type]++;
317 icp->icmp_type = type;
318 if (type == ICMP_REDIRECT)
319 icp->icmp_gwaddr.s_addr = dest;
320 else {
321 icp->icmp_void = 0;
322 /*
323 * The following assignments assume an overlay with the
324 * zeroed icmp_void field.
325 */
326 if (type == ICMP_PARAMPROB) {
327 icp->icmp_pptr = code;
328 code = 0;
329 } else if (type == ICMP_UNREACH &&
330 code == ICMP_UNREACH_NEEDFRAG && destmtu)
331 icp->icmp_nextmtu = htons(destmtu);
332 }
333
334 icp->icmp_code = code;
335 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
336
337 /*
338 * Now, copy old ip header (without options)
339 * in front of icmp message.
340 */
341 if (m->m_data - sizeof(struct ip) < m->m_pktdat)
342 panic("icmp len");
343 m->m_data -= sizeof(struct ip);
344 m->m_len += sizeof(struct ip);
345 m->m_pkthdr.len = m->m_len;
346 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
347 nip = mtod(m, struct ip *);
348 /* ip_v set in ip_output */
349 nip->ip_hl = sizeof(struct ip) >> 2;
350 nip->ip_tos = 0;
351 nip->ip_len = htons(m->m_len);
352 /* ip_id set in ip_output */
353 nip->ip_off = htons(0);
354 /* ip_ttl set in icmp_reflect */
355 nip->ip_p = IPPROTO_ICMP;
356 nip->ip_src = oip->ip_src;
357 nip->ip_dst = oip->ip_dst;
358 /* move PF_GENERATED m_tag to new packet, if it exists */
359 mtag = m_tag_find(n, PACKET_TAG_PF_GENERATED, NULL);
360 if (mtag != NULL) {
361 m_tag_unlink(n, mtag);
362 m_tag_prepend(m, mtag);
363 }
364 icmp_reflect(m);
365
366 freeit:
367 m_freem(n);
368 }
369
370 struct sockaddr_in icmpsrc = {
371 .sin_len = sizeof (struct sockaddr_in),
372 .sin_family = AF_INET,
373 };
374 static struct sockaddr_in icmpdst = {
375 .sin_len = sizeof (struct sockaddr_in),
376 .sin_family = AF_INET,
377 };
378 static struct sockaddr_in icmpgw = {
379 .sin_len = sizeof (struct sockaddr_in),
380 .sin_family = AF_INET,
381 };
382 struct sockaddr_in icmpmask = {
383 .sin_len = 8,
384 .sin_family = 0,
385 };
386
387 /*
388 * Process a received ICMP message.
389 */
390 void
391 icmp_input(struct mbuf *m, ...)
392 {
393 int proto;
394 struct icmp *icp;
395 struct ip *ip = mtod(m, struct ip *);
396 int icmplen;
397 int i;
398 struct in_ifaddr *ia;
399 void *(*ctlfunc)(int, struct sockaddr *, void *);
400 int code;
401 int hlen;
402 va_list ap;
403 struct rtentry *rt;
404
405 va_start(ap, m);
406 hlen = va_arg(ap, int);
407 proto = va_arg(ap, int);
408 va_end(ap);
409
410 /*
411 * Locate icmp structure in mbuf, and check
412 * that not corrupted and of at least minimum length.
413 */
414 icmplen = ntohs(ip->ip_len) - hlen;
415 #ifdef ICMPPRINTFS
416 if (icmpprintfs) {
417 printf("icmp_input from `%s' to ", inet_ntoa(ip->ip_src));
418 printf("`%s', len %d\n", inet_ntoa(ip->ip_dst), icmplen);
419 }
420 #endif
421 if (icmplen < ICMP_MINLEN) {
422 icmpstat.icps_tooshort++;
423 goto freeit;
424 }
425 i = hlen + min(icmplen, ICMP_ADVLENMIN);
426 if ((m->m_len < i || M_READONLY(m)) && (m = m_pullup(m, i)) == 0) {
427 icmpstat.icps_tooshort++;
428 return;
429 }
430 ip = mtod(m, struct ip *);
431 m->m_len -= hlen;
432 m->m_data += hlen;
433 icp = mtod(m, struct icmp *);
434 /* Don't need to assert alignment, here. */
435 if (in_cksum(m, icmplen)) {
436 icmpstat.icps_checksum++;
437 goto freeit;
438 }
439 m->m_len += hlen;
440 m->m_data -= hlen;
441
442 #ifdef ICMPPRINTFS
443 /*
444 * Message type specific processing.
445 */
446 if (icmpprintfs)
447 printf("icmp_input(type:%d, code:%d)\n", icp->icmp_type,
448 icp->icmp_code);
449 #endif
450 if (icp->icmp_type > ICMP_MAXTYPE)
451 goto raw;
452 icmpstat.icps_inhist[icp->icmp_type]++;
453 code = icp->icmp_code;
454 switch (icp->icmp_type) {
455
456 case ICMP_UNREACH:
457 switch (code) {
458 case ICMP_UNREACH_NET:
459 code = PRC_UNREACH_NET;
460 break;
461
462 case ICMP_UNREACH_HOST:
463 code = PRC_UNREACH_HOST;
464 break;
465
466 case ICMP_UNREACH_PROTOCOL:
467 code = PRC_UNREACH_PROTOCOL;
468 break;
469
470 case ICMP_UNREACH_PORT:
471 code = PRC_UNREACH_PORT;
472 break;
473
474 case ICMP_UNREACH_SRCFAIL:
475 code = PRC_UNREACH_SRCFAIL;
476 break;
477
478 case ICMP_UNREACH_NEEDFRAG:
479 code = PRC_MSGSIZE;
480 break;
481
482 case ICMP_UNREACH_NET_UNKNOWN:
483 case ICMP_UNREACH_NET_PROHIB:
484 case ICMP_UNREACH_TOSNET:
485 code = PRC_UNREACH_NET;
486 break;
487
488 case ICMP_UNREACH_HOST_UNKNOWN:
489 case ICMP_UNREACH_ISOLATED:
490 case ICMP_UNREACH_HOST_PROHIB:
491 case ICMP_UNREACH_TOSHOST:
492 code = PRC_UNREACH_HOST;
493 break;
494
495 default:
496 goto badcode;
497 }
498 goto deliver;
499
500 case ICMP_TIMXCEED:
501 if (code > 1)
502 goto badcode;
503 code += PRC_TIMXCEED_INTRANS;
504 goto deliver;
505
506 case ICMP_PARAMPROB:
507 if (code > 1)
508 goto badcode;
509 code = PRC_PARAMPROB;
510 goto deliver;
511
512 case ICMP_SOURCEQUENCH:
513 if (code)
514 goto badcode;
515 code = PRC_QUENCH;
516 goto deliver;
517
518 deliver:
519 /*
520 * Problem with datagram; advise higher level routines.
521 */
522 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
523 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
524 icmpstat.icps_badlen++;
525 goto freeit;
526 }
527 if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr))
528 goto badcode;
529 #ifdef ICMPPRINTFS
530 if (icmpprintfs)
531 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
532 #endif
533 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
534 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
535 if (ctlfunc)
536 (void) (*ctlfunc)(code, sintosa(&icmpsrc),
537 &icp->icmp_ip);
538 break;
539
540 badcode:
541 icmpstat.icps_badcode++;
542 break;
543
544 case ICMP_ECHO:
545 icp->icmp_type = ICMP_ECHOREPLY;
546 goto reflect;
547
548 case ICMP_TSTAMP:
549 if (icmplen < ICMP_TSLEN) {
550 icmpstat.icps_badlen++;
551 break;
552 }
553 icp->icmp_type = ICMP_TSTAMPREPLY;
554 icp->icmp_rtime = iptime();
555 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
556 goto reflect;
557
558 case ICMP_MASKREQ:
559 if (icmpmaskrepl == 0)
560 break;
561 /*
562 * We are not able to respond with all ones broadcast
563 * unless we receive it over a point-to-point interface.
564 */
565 if (icmplen < ICMP_MASKLEN) {
566 icmpstat.icps_badlen++;
567 break;
568 }
569 if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
570 in_nullhost(ip->ip_dst))
571 icmpdst.sin_addr = ip->ip_src;
572 else
573 icmpdst.sin_addr = ip->ip_dst;
574 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst),
575 m->m_pkthdr.rcvif));
576 if (ia == 0)
577 break;
578 icp->icmp_type = ICMP_MASKREPLY;
579 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
580 if (in_nullhost(ip->ip_src)) {
581 if (ia->ia_ifp->if_flags & IFF_BROADCAST)
582 ip->ip_src = ia->ia_broadaddr.sin_addr;
583 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
584 ip->ip_src = ia->ia_dstaddr.sin_addr;
585 }
586 reflect:
587 icmpstat.icps_reflect++;
588 icmpstat.icps_outhist[icp->icmp_type]++;
589 icmp_reflect(m);
590 return;
591
592 case ICMP_REDIRECT:
593 if (code > 3)
594 goto badcode;
595 if (icmp_rediraccept == 0)
596 goto freeit;
597 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
598 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
599 icmpstat.icps_badlen++;
600 break;
601 }
602 /*
603 * Short circuit routing redirects to force
604 * immediate change in the kernel's routing
605 * tables. The message is also handed to anyone
606 * listening on a raw socket (e.g. the routing
607 * daemon for use in updating its tables).
608 */
609 icmpgw.sin_addr = ip->ip_src;
610 icmpdst.sin_addr = icp->icmp_gwaddr;
611 #ifdef ICMPPRINTFS
612 if (icmpprintfs) {
613 printf("redirect dst `%s' to `%s'\n",
614 inet_ntoa(icp->icmp_ip.ip_dst),
615 inet_ntoa(icp->icmp_gwaddr));
616 }
617 #endif
618 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
619 rt = NULL;
620 rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst),
621 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
622 sintosa(&icmpgw), (struct rtentry **)&rt);
623 if (rt != NULL && icmp_redirtimeout != 0) {
624 i = rt_timer_add(rt, icmp_redirect_timeout,
625 icmp_redirect_timeout_q);
626 if (i)
627 log(LOG_ERR, "ICMP: redirect failed to "
628 "register timeout for route to %x, "
629 "code %d\n",
630 icp->icmp_ip.ip_dst.s_addr, i);
631 }
632 if (rt != NULL)
633 rtfree(rt);
634
635 pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc));
636 #if defined(IPSEC) || defined(FAST_IPSEC)
637 key_sa_routechange((struct sockaddr *)&icmpsrc);
638 #endif
639 break;
640
641 /*
642 * No kernel processing for the following;
643 * just fall through to send to raw listener.
644 */
645 case ICMP_ECHOREPLY:
646 case ICMP_ROUTERADVERT:
647 case ICMP_ROUTERSOLICIT:
648 case ICMP_TSTAMPREPLY:
649 case ICMP_IREQREPLY:
650 case ICMP_MASKREPLY:
651 default:
652 break;
653 }
654
655 raw:
656 rip_input(m, hlen, proto);
657 return;
658
659 freeit:
660 m_freem(m);
661 return;
662 }
663
664 /*
665 * Reflect the ip packet back to the source
666 */
667 void
668 icmp_reflect(struct mbuf *m)
669 {
670 struct ip *ip = mtod(m, struct ip *);
671 struct in_ifaddr *ia;
672 struct ifaddr *ifa;
673 struct sockaddr_in *sin = 0;
674 struct in_addr t;
675 struct mbuf *opts = 0;
676 int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
677
678 if (!in_canforward(ip->ip_src) &&
679 ((ip->ip_src.s_addr & IN_CLASSA_NET) !=
680 htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) {
681 m_freem(m); /* Bad return address */
682 goto done; /* ip_output() will check for broadcast */
683 }
684 t = ip->ip_dst;
685 ip->ip_dst = ip->ip_src;
686 /*
687 * If the incoming packet was addressed directly to us, use
688 * dst as the src for the reply. Otherwise (broadcast or
689 * anonymous), use an address which corresponds to the
690 * incoming interface, with a preference for the address which
691 * corresponds to the route to the destination of the ICMP.
692 */
693
694 /* Look for packet addressed to us */
695 INADDR_TO_IA(t, ia);
696
697 /* look for packet sent to broadcast address */
698 if (ia == NULL && m->m_pkthdr.rcvif &&
699 (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) {
700 IFADDR_FOREACH(ifa, m->m_pkthdr.rcvif) {
701 if (ifa->ifa_addr->sa_family != AF_INET)
702 continue;
703 if (in_hosteq(t,ifatoia(ifa)->ia_broadaddr.sin_addr)) {
704 ia = ifatoia(ifa);
705 break;
706 }
707 }
708 }
709
710 if (ia)
711 sin = &ia->ia_addr;
712
713 icmpdst.sin_addr = t;
714
715 /*
716 * if the packet is addressed somewhere else, compute the
717 * source address for packets routed back to the source, and
718 * use that, if it's an address on the interface which
719 * received the packet
720 */
721 if (sin == (struct sockaddr_in *)0 && m->m_pkthdr.rcvif) {
722 struct sockaddr_in sin_dst;
723 struct route icmproute;
724 int errornum;
725
726 sin_dst.sin_family = AF_INET;
727 sin_dst.sin_len = sizeof(struct sockaddr_in);
728 sin_dst.sin_addr = ip->ip_dst;
729 bzero(&icmproute, sizeof(icmproute));
730 errornum = 0;
731 sin = in_selectsrc(&sin_dst, &icmproute, 0, NULL, &errornum);
732 /* errornum is never used */
733 if (icmproute.ro_rt)
734 RTFREE(icmproute.ro_rt);
735 /* check to make sure sin is a source address on rcvif */
736 if (sin) {
737 t = sin->sin_addr;
738 sin = (struct sockaddr_in *)0;
739 INADDR_TO_IA(t, ia);
740 while (ia) {
741 if (ia->ia_ifp == m->m_pkthdr.rcvif) {
742 sin = &ia->ia_addr;
743 break;
744 }
745 NEXT_IA_WITH_SAME_ADDR(ia);
746 }
747 }
748 }
749
750 /*
751 * if it was not addressed to us, but the route doesn't go out
752 * the source interface, pick an address on the source
753 * interface. This can happen when routing is asymmetric, or
754 * when the incoming packet was encapsulated
755 */
756 if (sin == (struct sockaddr_in *)0 && m->m_pkthdr.rcvif) {
757 IFADDR_FOREACH(ifa, m->m_pkthdr.rcvif) {
758 if (ifa->ifa_addr->sa_family != AF_INET)
759 continue;
760 sin = &(ifatoia(ifa)->ia_addr);
761 break;
762 }
763 }
764
765 /*
766 * The following happens if the packet was not addressed to us,
767 * and was received on an interface with no IP address:
768 * We find the first AF_INET address on the first non-loopback
769 * interface.
770 */
771 if (sin == (struct sockaddr_in *)0)
772 TAILQ_FOREACH(ia, &in_ifaddrhead, ia_list) {
773 if (ia->ia_ifp->if_flags & IFF_LOOPBACK)
774 continue;
775 sin = &ia->ia_addr;
776 break;
777 }
778
779 /*
780 * If we still didn't find an address, punt. We could have an
781 * interface up (and receiving packets) with no address.
782 */
783 if (sin == (struct sockaddr_in *)0) {
784 m_freem(m);
785 goto done;
786 }
787
788 ip->ip_src = sin->sin_addr;
789 ip->ip_ttl = MAXTTL;
790
791 if (optlen > 0) {
792 u_char *cp;
793 int opt, cnt;
794 u_int len;
795
796 /*
797 * Retrieve any source routing from the incoming packet;
798 * add on any record-route or timestamp options.
799 */
800 cp = (u_char *) (ip + 1);
801 if ((opts = ip_srcroute()) == 0 &&
802 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) {
803 MCLAIM(opts, m->m_owner);
804 opts->m_len = sizeof(struct in_addr);
805 *mtod(opts, struct in_addr *) = zeroin_addr;
806 }
807 if (opts) {
808 #ifdef ICMPPRINTFS
809 if (icmpprintfs)
810 printf("icmp_reflect optlen %d rt %d => ",
811 optlen, opts->m_len);
812 #endif
813 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
814 opt = cp[IPOPT_OPTVAL];
815 if (opt == IPOPT_EOL)
816 break;
817 if (opt == IPOPT_NOP)
818 len = 1;
819 else {
820 if (cnt < IPOPT_OLEN + sizeof(*cp))
821 break;
822 len = cp[IPOPT_OLEN];
823 if (len < IPOPT_OLEN + sizeof(*cp) ||
824 len > cnt)
825 break;
826 }
827 /*
828 * Should check for overflow, but it "can't happen"
829 */
830 if (opt == IPOPT_RR || opt == IPOPT_TS ||
831 opt == IPOPT_SECURITY) {
832 bcopy((caddr_t)cp,
833 mtod(opts, caddr_t) + opts->m_len, len);
834 opts->m_len += len;
835 }
836 }
837 /* Terminate & pad, if necessary */
838 if ((cnt = opts->m_len % 4) != 0) {
839 for (; cnt < 4; cnt++) {
840 *(mtod(opts, caddr_t) + opts->m_len) =
841 IPOPT_EOL;
842 opts->m_len++;
843 }
844 }
845 #ifdef ICMPPRINTFS
846 if (icmpprintfs)
847 printf("%d\n", opts->m_len);
848 #endif
849 }
850 /*
851 * Now strip out original options by copying rest of first
852 * mbuf's data back, and adjust the IP length.
853 */
854 ip->ip_len = htons(ntohs(ip->ip_len) - optlen);
855 ip->ip_hl = sizeof(struct ip) >> 2;
856 m->m_len -= optlen;
857 if (m->m_flags & M_PKTHDR)
858 m->m_pkthdr.len -= optlen;
859 optlen += sizeof(struct ip);
860 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
861 (unsigned)(m->m_len - sizeof(struct ip)));
862 }
863 m_tag_delete_nonpersistent(m);
864 m->m_flags &= ~(M_BCAST|M_MCAST);
865
866 /*
867 * Clear any in-bound checksum flags for this packet.
868 */
869 if (m->m_flags & M_PKTHDR)
870 m->m_pkthdr.csum_flags = 0;
871
872 icmp_send(m, opts);
873 done:
874 if (opts)
875 (void)m_free(opts);
876 }
877
878 /*
879 * Send an icmp packet back to the ip level,
880 * after supplying a checksum.
881 */
882 void
883 icmp_send(struct mbuf *m, struct mbuf *opts)
884 {
885 struct ip *ip = mtod(m, struct ip *);
886 int hlen;
887 struct icmp *icp;
888
889 hlen = ip->ip_hl << 2;
890 m->m_data += hlen;
891 m->m_len -= hlen;
892 icp = mtod(m, struct icmp *);
893 icp->icmp_cksum = 0;
894 icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen);
895 m->m_data -= hlen;
896 m->m_len += hlen;
897 #ifdef ICMPPRINTFS
898 if (icmpprintfs) {
899 printf("icmp_send to destination `%s' from `%s'\n",
900 inet_ntoa(ip->ip_dst), inet_ntoa(ip->ip_src));
901 }
902 #endif
903 (void) ip_output(m, opts, NULL, 0,
904 (struct ip_moptions *)NULL, (struct socket *)NULL);
905 }
906
907 n_time
908 iptime(void)
909 {
910 struct timeval atv;
911 u_long t;
912
913 microtime(&atv);
914 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
915 return (htonl(t));
916 }
917
918 /*
919 * sysctl helper routine for net.inet.icmp.returndatabytes. ensures
920 * that the new value is in the correct range.
921 */
922 static int
923 sysctl_net_inet_icmp_returndatabytes(SYSCTLFN_ARGS)
924 {
925 int error, t;
926 struct sysctlnode node;
927
928 node = *rnode;
929 node.sysctl_data = &t;
930 t = icmpreturndatabytes;
931 error = sysctl_lookup(SYSCTLFN_CALL(&node));
932 if (error || newp == NULL)
933 return (error);
934
935 if (t < 8 || t > 512)
936 return (EINVAL);
937 icmpreturndatabytes = t;
938
939 return (0);
940 }
941
942 /*
943 * sysctl helper routine for net.inet.icmp.redirtimeout. ensures that
944 * the given value is not less than zero and then resets the timeout
945 * queue.
946 */
947 static int
948 sysctl_net_inet_icmp_redirtimeout(SYSCTLFN_ARGS)
949 {
950 int error, tmp;
951 struct sysctlnode node;
952
953 node = *rnode;
954 node.sysctl_data = &tmp;
955 tmp = icmp_redirtimeout;
956 error = sysctl_lookup(SYSCTLFN_CALL(&node));
957 if (error || newp == NULL)
958 return (error);
959 if (tmp < 0)
960 return (EINVAL);
961 icmp_redirtimeout = tmp;
962
963 /*
964 * was it a *defined* side-effect that anyone even *reading*
965 * this value causes these things to happen?
966 */
967 if (icmp_redirect_timeout_q != NULL) {
968 if (icmp_redirtimeout == 0) {
969 rt_timer_queue_destroy(icmp_redirect_timeout_q,
970 TRUE);
971 icmp_redirect_timeout_q = NULL;
972 } else {
973 rt_timer_queue_change(icmp_redirect_timeout_q,
974 icmp_redirtimeout);
975 }
976 } else if (icmp_redirtimeout > 0) {
977 icmp_redirect_timeout_q =
978 rt_timer_queue_create(icmp_redirtimeout);
979 }
980
981 return (0);
982 }
983
984 SYSCTL_SETUP(sysctl_net_inet_icmp_setup, "sysctl net.inet.icmp subtree setup")
985 {
986
987 sysctl_createv(clog, 0, NULL, NULL,
988 CTLFLAG_PERMANENT,
989 CTLTYPE_NODE, "net", NULL,
990 NULL, 0, NULL, 0,
991 CTL_NET, CTL_EOL);
992 sysctl_createv(clog, 0, NULL, NULL,
993 CTLFLAG_PERMANENT,
994 CTLTYPE_NODE, "inet", NULL,
995 NULL, 0, NULL, 0,
996 CTL_NET, PF_INET, CTL_EOL);
997 sysctl_createv(clog, 0, NULL, NULL,
998 CTLFLAG_PERMANENT,
999 CTLTYPE_NODE, "icmp",
1000 SYSCTL_DESCR("ICMPv4 related settings"),
1001 NULL, 0, NULL, 0,
1002 CTL_NET, PF_INET, IPPROTO_ICMP, CTL_EOL);
1003
1004 sysctl_createv(clog, 0, NULL, NULL,
1005 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1006 CTLTYPE_INT, "maskrepl",
1007 SYSCTL_DESCR("Respond to ICMP_MASKREQ messages"),
1008 NULL, 0, &icmpmaskrepl, 0,
1009 CTL_NET, PF_INET, IPPROTO_ICMP,
1010 ICMPCTL_MASKREPL, CTL_EOL);
1011 sysctl_createv(clog, 0, NULL, NULL,
1012 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1013 CTLTYPE_INT, "returndatabytes",
1014 SYSCTL_DESCR("Number of bytes to return in an ICMP "
1015 "error message"),
1016 sysctl_net_inet_icmp_returndatabytes, 0,
1017 &icmpreturndatabytes, 0,
1018 CTL_NET, PF_INET, IPPROTO_ICMP,
1019 ICMPCTL_RETURNDATABYTES, CTL_EOL);
1020 sysctl_createv(clog, 0, NULL, NULL,
1021 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1022 CTLTYPE_INT, "errppslimit",
1023 SYSCTL_DESCR("Maximum number of outgoing ICMP error "
1024 "messages per second"),
1025 NULL, 0, &icmperrppslim, 0,
1026 CTL_NET, PF_INET, IPPROTO_ICMP,
1027 ICMPCTL_ERRPPSLIMIT, CTL_EOL);
1028 sysctl_createv(clog, 0, NULL, NULL,
1029 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1030 CTLTYPE_INT, "rediraccept",
1031 SYSCTL_DESCR("Accept ICMP_REDIRECT messages"),
1032 NULL, 0, &icmp_rediraccept, 0,
1033 CTL_NET, PF_INET, IPPROTO_ICMP,
1034 ICMPCTL_REDIRACCEPT, CTL_EOL);
1035 sysctl_createv(clog, 0, NULL, NULL,
1036 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1037 CTLTYPE_INT, "redirtimeout",
1038 SYSCTL_DESCR("Lifetime of ICMP_REDIRECT generated "
1039 "routes"),
1040 sysctl_net_inet_icmp_redirtimeout, 0,
1041 &icmp_redirtimeout, 0,
1042 CTL_NET, PF_INET, IPPROTO_ICMP,
1043 ICMPCTL_REDIRTIMEOUT, CTL_EOL);
1044 sysctl_createv(clog, 0, NULL, NULL,
1045 CTLFLAG_PERMANENT,
1046 CTLTYPE_STRUCT, "stats",
1047 SYSCTL_DESCR("ICMP statistics"),
1048 NULL, 0, &icmpstat, sizeof(icmpstat),
1049 CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_STATS,
1050 CTL_EOL);
1051 }
1052
1053 /* Table of common MTUs: */
1054
1055 static const u_int mtu_table[] = {
1056 65535, 65280, 32000, 17914, 9180, 8166,
1057 4352, 2002, 1492, 1006, 508, 296, 68, 0
1058 };
1059
1060 void
1061 icmp_mtudisc(struct icmp *icp, struct in_addr faddr)
1062 {
1063 struct icmp_mtudisc_callback *mc;
1064 struct sockaddr *dst = sintosa(&icmpsrc);
1065 struct rtentry *rt;
1066 u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */
1067 int error;
1068
1069 rt = rtalloc1(dst, 1);
1070 if (rt == 0)
1071 return;
1072
1073 /* If we didn't get a host route, allocate one */
1074
1075 if ((rt->rt_flags & RTF_HOST) == 0) {
1076 struct rtentry *nrt;
1077
1078 error = rtrequest((int) RTM_ADD, dst,
1079 (struct sockaddr *) rt->rt_gateway,
1080 (struct sockaddr *) 0,
1081 RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt);
1082 if (error) {
1083 rtfree(rt);
1084 return;
1085 }
1086 nrt->rt_rmx = rt->rt_rmx;
1087 rtfree(rt);
1088 rt = nrt;
1089 }
1090 error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q);
1091 if (error) {
1092 rtfree(rt);
1093 return;
1094 }
1095
1096 if (mtu == 0) {
1097 int i = 0;
1098
1099 mtu = ntohs(icp->icmp_ip.ip_len);
1100 /* Some 4.2BSD-based routers incorrectly adjust the ip_len */
1101 if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0)
1102 mtu -= (icp->icmp_ip.ip_hl << 2);
1103
1104 /* If we still can't guess a value, try the route */
1105
1106 if (mtu == 0) {
1107 mtu = rt->rt_rmx.rmx_mtu;
1108
1109 /* If no route mtu, default to the interface mtu */
1110
1111 if (mtu == 0)
1112 mtu = rt->rt_ifp->if_mtu;
1113 }
1114
1115 for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++)
1116 if (mtu > mtu_table[i]) {
1117 mtu = mtu_table[i];
1118 break;
1119 }
1120 }
1121
1122 /*
1123 * XXX: RTV_MTU is overloaded, since the admin can set it
1124 * to turn off PMTU for a route, and the kernel can
1125 * set it to indicate a serious problem with PMTU
1126 * on a route. We should be using a separate flag
1127 * for the kernel to indicate this.
1128 */
1129
1130 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) {
1131 if (mtu < 296 || mtu > rt->rt_ifp->if_mtu)
1132 rt->rt_rmx.rmx_locks |= RTV_MTU;
1133 else if (rt->rt_rmx.rmx_mtu > mtu ||
1134 rt->rt_rmx.rmx_mtu == 0) {
1135 icmpstat.icps_pmtuchg++;
1136 rt->rt_rmx.rmx_mtu = mtu;
1137 }
1138 }
1139
1140 if (rt)
1141 rtfree(rt);
1142
1143 /*
1144 * Notify protocols that the MTU for this destination
1145 * has changed.
1146 */
1147 for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL;
1148 mc = LIST_NEXT(mc, mc_list))
1149 (*mc->mc_func)(faddr);
1150 }
1151
1152 /*
1153 * Return the next larger or smaller MTU plateau (table from RFC 1191)
1154 * given current value MTU. If DIR is less than zero, a larger plateau
1155 * is returned; otherwise, a smaller value is returned.
1156 */
1157 u_int
1158 ip_next_mtu(u_int mtu, int dir) /* XXX */
1159 {
1160 int i;
1161
1162 for (i = 0; i < (sizeof mtu_table) / (sizeof mtu_table[0]); i++) {
1163 if (mtu >= mtu_table[i])
1164 break;
1165 }
1166
1167 if (dir < 0) {
1168 if (i == 0) {
1169 return 0;
1170 } else {
1171 return mtu_table[i - 1];
1172 }
1173 } else {
1174 if (mtu_table[i] == 0) {
1175 return 0;
1176 } else if (mtu > mtu_table[i]) {
1177 return mtu_table[i];
1178 } else {
1179 return mtu_table[i + 1];
1180 }
1181 }
1182 }
1183
1184 static void
1185 icmp_mtudisc_timeout(struct rtentry *rt, struct rttimer *r)
1186 {
1187 if (rt == NULL)
1188 panic("icmp_mtudisc_timeout: bad route to timeout");
1189 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) ==
1190 (RTF_DYNAMIC | RTF_HOST)) {
1191 rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt),
1192 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
1193 } else {
1194 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) {
1195 rt->rt_rmx.rmx_mtu = 0;
1196 }
1197 }
1198 }
1199
1200 static void
1201 icmp_redirect_timeout(struct rtentry *rt, struct rttimer *r)
1202 {
1203 if (rt == NULL)
1204 panic("icmp_redirect_timeout: bad route to timeout");
1205 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) ==
1206 (RTF_DYNAMIC | RTF_HOST)) {
1207 rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt),
1208 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
1209 }
1210 }
1211
1212 /*
1213 * Perform rate limit check.
1214 * Returns 0 if it is okay to send the icmp packet.
1215 * Returns 1 if the router SHOULD NOT send this icmp packet due to rate
1216 * limitation.
1217 *
1218 * XXX per-destination/type check necessary?
1219 */
1220 static int
1221 icmp_ratelimit(const struct in_addr *dst, const int type,
1222 const int code)
1223 {
1224
1225 /* PPS limit */
1226 if (!ppsratecheck(&icmperrppslim_last, &icmperrpps_count,
1227 icmperrppslim)) {
1228 /* The packet is subject to rate limit */
1229 return 1;
1230 }
1231
1232 /* okay to send */
1233 return 0;
1234 }
Cache object: 549b864f28a2ad8546ea23120edd0e84
|