1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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 * $KAME: icmp6.c,v 1.211 2001/04/04 05:56:20 itojun Exp $
32 */
33
34 /*-
35 * Copyright (c) 1982, 1986, 1988, 1993
36 * The Regents of the University of California. All rights reserved.
37 *
38 * Redistribution and use in source and binary forms, with or without
39 * modification, are permitted provided that the following conditions
40 * are met:
41 * 1. Redistributions of source code must retain the above copyright
42 * notice, this list of conditions and the following disclaimer.
43 * 2. Redistributions in binary form must reproduce the above copyright
44 * notice, this list of conditions and the following disclaimer in the
45 * documentation and/or other materials provided with the distribution.
46 * 3. Neither the name of the University nor the names of its contributors
47 * may be used to endorse or promote products derived from this software
48 * without specific prior written permission.
49 *
50 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60 * SUCH DAMAGE.
61 *
62 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
63 */
64
65 #include <sys/cdefs.h>
66 #define MBUF_PRIVATE /* XXXRW: Optimisation tries to avoid M_EXT mbufs */
67
68 #include "opt_inet.h"
69 #include "opt_inet6.h"
70
71 #include <sys/param.h>
72 #include <sys/domain.h>
73 #include <sys/jail.h>
74 #include <sys/kernel.h>
75 #include <sys/lock.h>
76 #include <sys/malloc.h>
77 #include <sys/mbuf.h>
78 #include <sys/proc.h>
79 #include <sys/protosw.h>
80 #include <sys/signalvar.h>
81 #include <sys/socket.h>
82 #include <sys/socketvar.h>
83 #include <sys/sx.h>
84 #include <sys/syslog.h>
85 #include <sys/systm.h>
86 #include <sys/time.h>
87
88 #include <net/if.h>
89 #include <net/if_var.h>
90 #include <net/if_dl.h>
91 #include <net/if_llatbl.h>
92 #include <net/if_types.h>
93 #include <net/route.h>
94 #include <net/route/route_ctl.h>
95 #include <net/route/nhop.h>
96 #include <net/vnet.h>
97
98 #include <netinet/in.h>
99 #include <netinet/in_pcb.h>
100 #include <netinet/in_var.h>
101 #include <netinet/ip6.h>
102 #include <netinet/icmp6.h>
103 #include <netinet/tcp_var.h>
104
105 #include <netinet6/in6_fib.h>
106 #include <netinet6/in6_ifattach.h>
107 #include <netinet6/in6_pcb.h>
108 #include <netinet6/ip6protosw.h>
109 #include <netinet6/ip6_var.h>
110 #include <netinet6/scope6_var.h>
111 #include <netinet6/mld6_var.h>
112 #include <netinet6/nd6.h>
113 #include <netinet6/send.h>
114
115 extern struct domain inet6domain;
116
117 VNET_PCPUSTAT_DEFINE(struct icmp6stat, icmp6stat);
118 VNET_PCPUSTAT_SYSINIT(icmp6stat);
119
120 #ifdef VIMAGE
121 VNET_PCPUSTAT_SYSUNINIT(icmp6stat);
122 #endif /* VIMAGE */
123
124 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
125 VNET_DECLARE(struct inpcbhead, ripcb);
126 VNET_DECLARE(int, icmp6_nodeinfo);
127
128 #define V_ripcbinfo VNET(ripcbinfo)
129 #define V_ripcb VNET(ripcb)
130 #define V_icmp6_nodeinfo VNET(icmp6_nodeinfo)
131
132 static void icmp6_errcount(int, int);
133 static int icmp6_rip6_input(struct mbuf **, int);
134 static void icmp6_reflect(struct mbuf *, size_t);
135 static int icmp6_ratelimit(const struct in6_addr *, const int, const int);
136 static const char *icmp6_redirect_diag(struct in6_addr *,
137 struct in6_addr *, struct in6_addr *);
138 static struct mbuf *ni6_input(struct mbuf *, int, struct prison *);
139 static struct mbuf *ni6_nametodns(const char *, int, int);
140 static int ni6_dnsmatch(const char *, int, const char *, int);
141 static int ni6_addrs(struct icmp6_nodeinfo *, struct mbuf *,
142 struct ifnet **, struct in6_addr *);
143 static int ni6_store_addrs(struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
144 struct ifnet *, int);
145 static int icmp6_notify_error(struct mbuf **, int, int, int);
146
147 /*
148 * Kernel module interface for updating icmp6stat. The argument is an index
149 * into icmp6stat treated as an array of u_quad_t. While this encodes the
150 * general layout of icmp6stat into the caller, it doesn't encode its
151 * location, so that future changes to add, for example, per-CPU stats
152 * support won't cause binary compatibility problems for kernel modules.
153 */
154 void
kmod_icmp6stat_inc(int statnum)155 kmod_icmp6stat_inc(int statnum)
156 {
157
158 counter_u64_add(VNET(icmp6stat)[statnum], 1);
159 }
160
161 static void
icmp6_errcount(int type,int code)162 icmp6_errcount(int type, int code)
163 {
164 switch (type) {
165 case ICMP6_DST_UNREACH:
166 switch (code) {
167 case ICMP6_DST_UNREACH_NOROUTE:
168 ICMP6STAT_INC(icp6s_odst_unreach_noroute);
169 return;
170 case ICMP6_DST_UNREACH_ADMIN:
171 ICMP6STAT_INC(icp6s_odst_unreach_admin);
172 return;
173 case ICMP6_DST_UNREACH_BEYONDSCOPE:
174 ICMP6STAT_INC(icp6s_odst_unreach_beyondscope);
175 return;
176 case ICMP6_DST_UNREACH_ADDR:
177 ICMP6STAT_INC(icp6s_odst_unreach_addr);
178 return;
179 case ICMP6_DST_UNREACH_NOPORT:
180 ICMP6STAT_INC(icp6s_odst_unreach_noport);
181 return;
182 }
183 break;
184 case ICMP6_PACKET_TOO_BIG:
185 ICMP6STAT_INC(icp6s_opacket_too_big);
186 return;
187 case ICMP6_TIME_EXCEEDED:
188 switch (code) {
189 case ICMP6_TIME_EXCEED_TRANSIT:
190 ICMP6STAT_INC(icp6s_otime_exceed_transit);
191 return;
192 case ICMP6_TIME_EXCEED_REASSEMBLY:
193 ICMP6STAT_INC(icp6s_otime_exceed_reassembly);
194 return;
195 }
196 break;
197 case ICMP6_PARAM_PROB:
198 switch (code) {
199 case ICMP6_PARAMPROB_HEADER:
200 ICMP6STAT_INC(icp6s_oparamprob_header);
201 return;
202 case ICMP6_PARAMPROB_NEXTHEADER:
203 ICMP6STAT_INC(icp6s_oparamprob_nextheader);
204 return;
205 case ICMP6_PARAMPROB_OPTION:
206 ICMP6STAT_INC(icp6s_oparamprob_option);
207 return;
208 }
209 break;
210 case ND_REDIRECT:
211 ICMP6STAT_INC(icp6s_oredirect);
212 return;
213 }
214 ICMP6STAT_INC(icp6s_ounknown);
215 }
216
217 /*
218 * A wrapper function for icmp6_error() necessary when the erroneous packet
219 * may not contain enough scope zone information.
220 */
221 void
icmp6_error2(struct mbuf * m,int type,int code,int param,struct ifnet * ifp)222 icmp6_error2(struct mbuf *m, int type, int code, int param,
223 struct ifnet *ifp)
224 {
225 struct ip6_hdr *ip6;
226
227 if (ifp == NULL)
228 return;
229
230 if (m->m_len < sizeof(struct ip6_hdr)) {
231 m = m_pullup(m, sizeof(struct ip6_hdr));
232 if (m == NULL) {
233 IP6STAT_INC(ip6s_exthdrtoolong);
234 return;
235 }
236 }
237 ip6 = mtod(m, struct ip6_hdr *);
238
239 if (in6_setscope(&ip6->ip6_src, ifp, NULL) != 0)
240 return;
241 if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
242 return;
243
244 icmp6_error(m, type, code, param);
245 }
246
247 /*
248 * Generate an error packet of type error in response to bad IP6 packet.
249 */
250 void
icmp6_error(struct mbuf * m,int type,int code,int param)251 icmp6_error(struct mbuf *m, int type, int code, int param)
252 {
253 struct ip6_hdr *oip6, *nip6;
254 struct icmp6_hdr *icmp6;
255 struct epoch_tracker et;
256 u_int preplen;
257 int off;
258 int nxt;
259
260 ICMP6STAT_INC(icp6s_error);
261
262 /* count per-type-code statistics */
263 icmp6_errcount(type, code);
264
265 #ifdef M_DECRYPTED /*not openbsd*/
266 if (m->m_flags & M_DECRYPTED) {
267 ICMP6STAT_INC(icp6s_canterror);
268 goto freeit;
269 }
270 #endif
271
272 if (m->m_len < sizeof(struct ip6_hdr)) {
273 m = m_pullup(m, sizeof(struct ip6_hdr));
274 if (m == NULL) {
275 IP6STAT_INC(ip6s_exthdrtoolong);
276 return;
277 }
278 }
279 oip6 = mtod(m, struct ip6_hdr *);
280
281 /*
282 * If the destination address of the erroneous packet is a multicast
283 * address, or the packet was sent using link-layer multicast,
284 * we should basically suppress sending an error (RFC 2463, Section
285 * 2.4).
286 * We have two exceptions (the item e.2 in that section):
287 * - the Packet Too Big message can be sent for path MTU discovery.
288 * - the Parameter Problem Message that can be allowed an icmp6 error
289 * in the option type field. This check has been done in
290 * ip6_unknown_opt(), so we can just check the type and code.
291 */
292 if ((m->m_flags & (M_BCAST|M_MCAST) ||
293 IN6_IS_ADDR_MULTICAST(&oip6->ip6_dst)) &&
294 (type != ICMP6_PACKET_TOO_BIG &&
295 (type != ICMP6_PARAM_PROB ||
296 code != ICMP6_PARAMPROB_OPTION)))
297 goto freeit;
298
299 /*
300 * RFC 2463, 2.4 (e.5): source address check.
301 * XXX: the case of anycast source?
302 */
303 if (IN6_IS_ADDR_UNSPECIFIED(&oip6->ip6_src) ||
304 IN6_IS_ADDR_MULTICAST(&oip6->ip6_src))
305 goto freeit;
306
307 /*
308 * If we are about to send ICMPv6 against ICMPv6 error/redirect,
309 * don't do it.
310 */
311 nxt = -1;
312 off = ip6_lasthdr(m, 0, IPPROTO_IPV6, &nxt);
313 if (off >= 0 && nxt == IPPROTO_ICMPV6) {
314 struct icmp6_hdr *icp;
315
316 if (m->m_len < off + sizeof(struct icmp6_hdr)) {
317 m = m_pullup(m, off + sizeof(struct icmp6_hdr));
318 if (m == NULL) {
319 IP6STAT_INC(ip6s_exthdrtoolong);
320 return;
321 }
322 }
323 oip6 = mtod(m, struct ip6_hdr *);
324 icp = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
325
326 if (icp->icmp6_type < ICMP6_ECHO_REQUEST ||
327 icp->icmp6_type == ND_REDIRECT) {
328 /*
329 * ICMPv6 error
330 * Special case: for redirect (which is
331 * informational) we must not send icmp6 error.
332 */
333 ICMP6STAT_INC(icp6s_canterror);
334 goto freeit;
335 } else {
336 /* ICMPv6 informational - send the error */
337 }
338 } else {
339 /* non-ICMPv6 - send the error */
340 }
341
342 /* Finally, do rate limitation check. */
343 if (icmp6_ratelimit(&oip6->ip6_src, type, code))
344 goto freeit;
345
346 /*
347 * OK, ICMP6 can be generated.
348 */
349
350 if (m->m_pkthdr.len >= ICMPV6_PLD_MAXLEN)
351 m_adj(m, ICMPV6_PLD_MAXLEN - m->m_pkthdr.len);
352
353 preplen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
354 M_PREPEND(m, preplen, M_NOWAIT); /* FIB is also copied over. */
355 if (m == NULL) {
356 nd6log((LOG_DEBUG, "ENOBUFS in icmp6_error %d\n", __LINE__));
357 return;
358 }
359
360 nip6 = mtod(m, struct ip6_hdr *);
361 nip6->ip6_src = oip6->ip6_src;
362 nip6->ip6_dst = oip6->ip6_dst;
363
364 in6_clearscope(&oip6->ip6_src);
365 in6_clearscope(&oip6->ip6_dst);
366
367 icmp6 = (struct icmp6_hdr *)(nip6 + 1);
368 icmp6->icmp6_type = type;
369 icmp6->icmp6_code = code;
370 icmp6->icmp6_pptr = htonl((u_int32_t)param);
371
372 ICMP6STAT_INC(icp6s_outhist[type]);
373 NET_EPOCH_ENTER(et);
374 icmp6_reflect(m, sizeof(struct ip6_hdr)); /* header order: IPv6 - ICMPv6 */
375 NET_EPOCH_EXIT(et);
376
377 return;
378
379 freeit:
380 /*
381 * If we can't tell whether or not we can generate ICMP6, free it.
382 */
383 m_freem(m);
384 }
385
386 /*
387 * Process a received ICMP6 message.
388 */
389 int
icmp6_input(struct mbuf ** mp,int * offp,int proto)390 icmp6_input(struct mbuf **mp, int *offp, int proto)
391 {
392 struct mbuf *m, *n;
393 struct ifnet *ifp;
394 struct ip6_hdr *ip6, *nip6;
395 struct icmp6_hdr *icmp6, *nicmp6;
396 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
397 int code, error, icmp6len, ip6len, noff, off, sum;
398
399 NET_EPOCH_ASSERT();
400
401 m = *mp;
402 off = *offp;
403
404 if (m->m_len < off + sizeof(struct icmp6_hdr)) {
405 m = m_pullup(m, off + sizeof(struct icmp6_hdr));
406 if (m == NULL) {
407 IP6STAT_INC(ip6s_exthdrtoolong);
408 *mp = m;
409 return (IPPROTO_DONE);
410 }
411 }
412
413 /*
414 * Locate icmp6 structure in mbuf, and check
415 * that not corrupted and of at least minimum length
416 */
417
418 icmp6len = m->m_pkthdr.len - off;
419 if (icmp6len < sizeof(struct icmp6_hdr)) {
420 ICMP6STAT_INC(icp6s_tooshort);
421 goto freeit;
422 }
423
424 ip6 = mtod(m, struct ip6_hdr *);
425 ifp = m->m_pkthdr.rcvif;
426 /*
427 * Check multicast group membership.
428 * Note: SSM filters are not applied for ICMPv6 traffic.
429 */
430 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
431 struct in6_multi *inm;
432
433 inm = in6m_lookup(ifp, &ip6->ip6_dst);
434 if (inm == NULL) {
435 IP6STAT_INC(ip6s_notmember);
436 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
437 goto freeit;
438 }
439 }
440
441 /* Calculate the checksum. */
442 icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
443 code = icmp6->icmp6_code;
444 if ((sum = in6_cksum(m, IPPROTO_ICMPV6, off, icmp6len)) != 0) {
445 nd6log((LOG_ERR,
446 "ICMP6 checksum error(%d|%x) %s\n",
447 icmp6->icmp6_type, sum,
448 ip6_sprintf(ip6bufs, &ip6->ip6_src)));
449 ICMP6STAT_INC(icp6s_checksum);
450 goto freeit;
451 }
452
453 ICMP6STAT_INC(icp6s_inhist[icmp6->icmp6_type]);
454 icmp6_ifstat_inc(ifp, ifs6_in_msg);
455 if (icmp6->icmp6_type < ICMP6_INFOMSG_MASK)
456 icmp6_ifstat_inc(ifp, ifs6_in_error);
457
458 ip6len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
459 switch (icmp6->icmp6_type) {
460 case ICMP6_DST_UNREACH:
461 icmp6_ifstat_inc(ifp, ifs6_in_dstunreach);
462 switch (code) {
463 case ICMP6_DST_UNREACH_NOROUTE:
464 case ICMP6_DST_UNREACH_ADDR: /* PRC_HOSTDEAD is a DOS */
465 code = PRC_UNREACH_NET;
466 break;
467 case ICMP6_DST_UNREACH_ADMIN:
468 icmp6_ifstat_inc(ifp, ifs6_in_adminprohib);
469 code = PRC_UNREACH_ADMIN_PROHIB;
470 break;
471 case ICMP6_DST_UNREACH_BEYONDSCOPE:
472 /* I mean "source address was incorrect." */
473 code = PRC_PARAMPROB;
474 break;
475 case ICMP6_DST_UNREACH_NOPORT:
476 code = PRC_UNREACH_PORT;
477 break;
478 default:
479 goto badcode;
480 }
481 goto deliver;
482 break;
483
484 case ICMP6_PACKET_TOO_BIG:
485 icmp6_ifstat_inc(ifp, ifs6_in_pkttoobig);
486
487 /* validation is made in icmp6_mtudisc_update */
488
489 code = PRC_MSGSIZE;
490
491 /*
492 * Updating the path MTU will be done after examining
493 * intermediate extension headers.
494 */
495 goto deliver;
496 break;
497
498 case ICMP6_TIME_EXCEEDED:
499 icmp6_ifstat_inc(ifp, ifs6_in_timeexceed);
500 switch (code) {
501 case ICMP6_TIME_EXCEED_TRANSIT:
502 code = PRC_TIMXCEED_INTRANS;
503 break;
504 case ICMP6_TIME_EXCEED_REASSEMBLY:
505 code = PRC_TIMXCEED_REASS;
506 break;
507 default:
508 goto badcode;
509 }
510 goto deliver;
511 break;
512
513 case ICMP6_PARAM_PROB:
514 icmp6_ifstat_inc(ifp, ifs6_in_paramprob);
515 switch (code) {
516 case ICMP6_PARAMPROB_NEXTHEADER:
517 code = PRC_UNREACH_PROTOCOL;
518 break;
519 case ICMP6_PARAMPROB_HEADER:
520 case ICMP6_PARAMPROB_OPTION:
521 code = PRC_PARAMPROB;
522 break;
523 default:
524 goto badcode;
525 }
526 goto deliver;
527 break;
528
529 case ICMP6_ECHO_REQUEST:
530 icmp6_ifstat_inc(ifp, ifs6_in_echo);
531 if (code != 0)
532 goto badcode;
533 if (icmp6_ratelimit(&ip6->ip6_src, ICMP6_ECHO_REPLY, 0))
534 break;
535 if ((n = m_copym(m, 0, M_COPYALL, M_NOWAIT)) == NULL) {
536 /* Give up remote */
537 break;
538 }
539 if (!M_WRITABLE(n)
540 || n->m_len < off + sizeof(struct icmp6_hdr)) {
541 struct mbuf *n0 = n;
542 int n0len;
543
544 CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) <= MHLEN);
545 n = m_gethdr(M_NOWAIT, n0->m_type);
546 if (n == NULL) {
547 /* Give up remote */
548 m_freem(n0);
549 break;
550 }
551
552 m_move_pkthdr(n, n0); /* FIB copied. */
553 n0len = n0->m_pkthdr.len; /* save for use below */
554 /*
555 * Copy IPv6 and ICMPv6 only.
556 */
557 nip6 = mtod(n, struct ip6_hdr *);
558 bcopy(ip6, nip6, sizeof(struct ip6_hdr));
559 nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
560 bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
561 noff = sizeof(struct ip6_hdr);
562 /* new mbuf contains only ipv6+icmpv6 headers */
563 n->m_len = noff + sizeof(struct icmp6_hdr);
564 /*
565 * Adjust mbuf. ip6_plen will be adjusted in
566 * ip6_output().
567 */
568 m_adj(n0, off + sizeof(struct icmp6_hdr));
569 /* recalculate complete packet size */
570 n->m_pkthdr.len = n0len + (noff - off);
571 n->m_next = n0;
572 } else {
573 if (n->m_len < off + sizeof(*nicmp6)) {
574 n = m_pullup(n, off + sizeof(*nicmp6));
575 if (n == NULL) {
576 IP6STAT_INC(ip6s_exthdrtoolong);
577 break;
578 }
579 }
580 nicmp6 = (struct icmp6_hdr *)(mtod(n, caddr_t) + off);
581 noff = off;
582 }
583 if (n) {
584 nicmp6->icmp6_type = ICMP6_ECHO_REPLY;
585 nicmp6->icmp6_code = 0;
586 ICMP6STAT_INC(icp6s_reflect);
587 ICMP6STAT_INC(icp6s_outhist[ICMP6_ECHO_REPLY]);
588 icmp6_reflect(n, noff);
589 }
590 break;
591
592 case ICMP6_ECHO_REPLY:
593 icmp6_ifstat_inc(ifp, ifs6_in_echoreply);
594 if (code != 0)
595 goto badcode;
596 break;
597
598 case MLD_LISTENER_QUERY:
599 case MLD_LISTENER_REPORT:
600 case MLD_LISTENER_DONE:
601 case MLDV2_LISTENER_REPORT:
602 /*
603 * Drop MLD traffic which is not link-local, has a hop limit
604 * of greater than 1 hop, or which does not have the
605 * IPv6 HBH Router Alert option.
606 * As IPv6 HBH options are stripped in ip6_input() we must
607 * check an mbuf header flag.
608 * XXX Should we also sanity check that these messages
609 * were directed to a link-local multicast prefix?
610 */
611 if ((ip6->ip6_hlim != 1) || (m->m_flags & M_RTALERT_MLD) == 0)
612 goto freeit;
613 if (mld_input(&m, off, icmp6len) != 0) {
614 *mp = NULL;
615 return (IPPROTO_DONE);
616 }
617 /* m stays. */
618 break;
619
620 case ICMP6_WRUREQUEST: /* ICMP6_FQDN_QUERY */
621 {
622 enum { WRU, FQDN } mode;
623 struct prison *pr;
624
625 if (!V_icmp6_nodeinfo)
626 break;
627
628 if (icmp6len == sizeof(struct icmp6_hdr) + 4)
629 mode = WRU;
630 else if (icmp6len >= sizeof(struct icmp6_nodeinfo))
631 mode = FQDN;
632 else
633 goto badlen;
634
635 pr = NULL;
636 sx_slock(&allprison_lock);
637 TAILQ_FOREACH(pr, &allprison, pr_list)
638 if (pr->pr_vnet == ifp->if_vnet)
639 break;
640 sx_sunlock(&allprison_lock);
641 if (pr == NULL)
642 pr = curthread->td_ucred->cr_prison;
643 if (mode == FQDN) {
644 if (m->m_len < off + sizeof(struct icmp6_nodeinfo)) {
645 m = m_pullup(m, off +
646 sizeof(struct icmp6_nodeinfo));
647 if (m == NULL) {
648 IP6STAT_INC(ip6s_exthdrtoolong);
649 *mp = m;
650 return (IPPROTO_DONE);
651 }
652 }
653 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
654 if (n)
655 n = ni6_input(n, off, pr);
656 /* XXX meaningless if n == NULL */
657 noff = sizeof(struct ip6_hdr);
658 } else {
659 u_char *p;
660 int maxhlen, hlen;
661
662 /*
663 * XXX: this combination of flags is pointless,
664 * but should we keep this for compatibility?
665 */
666 if ((V_icmp6_nodeinfo & (ICMP6_NODEINFO_FQDNOK |
667 ICMP6_NODEINFO_TMPADDROK)) !=
668 (ICMP6_NODEINFO_FQDNOK | ICMP6_NODEINFO_TMPADDROK))
669 break;
670
671 if (code != 0)
672 goto badcode;
673
674 CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) + 4 <= MHLEN);
675 n = m_gethdr(M_NOWAIT, m->m_type);
676 if (n == NULL) {
677 /* Give up remote */
678 break;
679 }
680 if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
681 /*
682 * Previous code did a blind M_COPY_PKTHDR
683 * and said "just for rcvif". If true, then
684 * we could tolerate the dup failing (due to
685 * the deep copy of the tag chain). For now
686 * be conservative and just fail.
687 */
688 m_free(n);
689 n = NULL;
690 break;
691 }
692 /*
693 * Copy IPv6 and ICMPv6 only.
694 */
695 nip6 = mtod(n, struct ip6_hdr *);
696 bcopy(ip6, nip6, sizeof(struct ip6_hdr));
697 nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
698 bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
699 p = (u_char *)(nicmp6 + 1);
700 bzero(p, 4);
701
702 maxhlen = M_TRAILINGSPACE(n) -
703 (sizeof(*nip6) + sizeof(*nicmp6) + 4);
704 mtx_lock(&pr->pr_mtx);
705 hlen = strlen(pr->pr_hostname);
706 if (maxhlen > hlen)
707 maxhlen = hlen;
708 /* meaningless TTL */
709 bcopy(pr->pr_hostname, p + 4, maxhlen);
710 mtx_unlock(&pr->pr_mtx);
711 noff = sizeof(struct ip6_hdr);
712 n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
713 sizeof(struct icmp6_hdr) + 4 + maxhlen;
714 nicmp6->icmp6_type = ICMP6_WRUREPLY;
715 nicmp6->icmp6_code = 0;
716 }
717 if (n) {
718 ICMP6STAT_INC(icp6s_reflect);
719 ICMP6STAT_INC(icp6s_outhist[ICMP6_WRUREPLY]);
720 icmp6_reflect(n, noff);
721 }
722 break;
723 }
724
725 case ICMP6_WRUREPLY:
726 if (code != 0)
727 goto badcode;
728 break;
729
730 case ND_ROUTER_SOLICIT:
731 icmp6_ifstat_inc(ifp, ifs6_in_routersolicit);
732 if (code != 0)
733 goto badcode;
734 if (icmp6len < sizeof(struct nd_router_solicit))
735 goto badlen;
736 if (send_sendso_input_hook != NULL) {
737 if (m->m_len < off + icmp6len) {
738 m = m_pullup(m, off + icmp6len);
739 if (m == NULL) {
740 IP6STAT_INC(ip6s_exthdrtoolong);
741 *mp = NULL;
742 return (IPPROTO_DONE);
743 }
744 }
745 error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
746 if (error == 0) {
747 m = NULL;
748 goto freeit;
749 }
750 }
751 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
752 nd6_rs_input(m, off, icmp6len);
753 m = n;
754 if (m == NULL)
755 goto freeit;
756 break;
757
758 case ND_ROUTER_ADVERT:
759 icmp6_ifstat_inc(ifp, ifs6_in_routeradvert);
760 if (code != 0)
761 goto badcode;
762 if (icmp6len < sizeof(struct nd_router_advert))
763 goto badlen;
764 if (send_sendso_input_hook != NULL) {
765 error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
766 if (error == 0) {
767 m = NULL;
768 goto freeit;
769 }
770 }
771 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
772 nd6_ra_input(m, off, icmp6len);
773 m = n;
774 if (m == NULL)
775 goto freeit;
776 break;
777
778 case ND_NEIGHBOR_SOLICIT:
779 icmp6_ifstat_inc(ifp, ifs6_in_neighborsolicit);
780 if (code != 0)
781 goto badcode;
782 if (icmp6len < sizeof(struct nd_neighbor_solicit))
783 goto badlen;
784 if (send_sendso_input_hook != NULL) {
785 error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
786 if (error == 0) {
787 m = NULL;
788 goto freeit;
789 }
790 }
791 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
792 nd6_ns_input(m, off, icmp6len);
793 m = n;
794 if (m == NULL)
795 goto freeit;
796 break;
797
798 case ND_NEIGHBOR_ADVERT:
799 icmp6_ifstat_inc(ifp, ifs6_in_neighboradvert);
800 if (code != 0)
801 goto badcode;
802 if (icmp6len < sizeof(struct nd_neighbor_advert))
803 goto badlen;
804 if (send_sendso_input_hook != NULL) {
805 error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
806 if (error == 0) {
807 m = NULL;
808 goto freeit;
809 }
810 }
811 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
812 nd6_na_input(m, off, icmp6len);
813 m = n;
814 if (m == NULL)
815 goto freeit;
816 break;
817
818 case ND_REDIRECT:
819 icmp6_ifstat_inc(ifp, ifs6_in_redirect);
820 if (code != 0)
821 goto badcode;
822 if (icmp6len < sizeof(struct nd_redirect))
823 goto badlen;
824 if (send_sendso_input_hook != NULL) {
825 error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
826 if (error == 0) {
827 m = NULL;
828 goto freeit;
829 }
830 }
831 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
832 icmp6_redirect_input(m, off);
833 m = n;
834 if (m == NULL)
835 goto freeit;
836 break;
837
838 case ICMP6_ROUTER_RENUMBERING:
839 if (code != ICMP6_ROUTER_RENUMBERING_COMMAND &&
840 code != ICMP6_ROUTER_RENUMBERING_RESULT)
841 goto badcode;
842 if (icmp6len < sizeof(struct icmp6_router_renum))
843 goto badlen;
844 break;
845
846 default:
847 nd6log((LOG_DEBUG,
848 "icmp6_input: unknown type %d(src=%s, dst=%s, ifid=%d)\n",
849 icmp6->icmp6_type, ip6_sprintf(ip6bufs, &ip6->ip6_src),
850 ip6_sprintf(ip6bufd, &ip6->ip6_dst),
851 ifp ? ifp->if_index : 0));
852 if (icmp6->icmp6_type < ICMP6_ECHO_REQUEST) {
853 /* ICMPv6 error: MUST deliver it by spec... */
854 code = PRC_NCMDS;
855 /* deliver */
856 } else {
857 /* ICMPv6 informational: MUST not deliver */
858 break;
859 }
860 deliver:
861 if (icmp6_notify_error(&m, off, icmp6len, code) != 0) {
862 /* In this case, m should've been freed. */
863 *mp = NULL;
864 return (IPPROTO_DONE);
865 }
866 break;
867
868 badcode:
869 ICMP6STAT_INC(icp6s_badcode);
870 break;
871
872 badlen:
873 ICMP6STAT_INC(icp6s_badlen);
874 break;
875 }
876
877 /* deliver the packet to appropriate sockets */
878 icmp6_rip6_input(&m, *offp);
879
880 *mp = m;
881 return (IPPROTO_DONE);
882
883 freeit:
884 m_freem(m);
885 *mp = NULL;
886 return (IPPROTO_DONE);
887 }
888
889 static int
icmp6_notify_error(struct mbuf ** mp,int off,int icmp6len,int code)890 icmp6_notify_error(struct mbuf **mp, int off, int icmp6len, int code)
891 {
892 struct mbuf *m;
893 struct icmp6_hdr *icmp6;
894 struct ip6_hdr *eip6;
895 u_int32_t notifymtu;
896 struct sockaddr_in6 icmp6src, icmp6dst;
897
898 m = *mp;
899
900 if (icmp6len < sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr)) {
901 ICMP6STAT_INC(icp6s_tooshort);
902 goto freeit;
903 }
904
905 if (m->m_len < off + sizeof(*icmp6) + sizeof(struct ip6_hdr)) {
906 m = m_pullup(m, off + sizeof(*icmp6) + sizeof(struct ip6_hdr));
907 if (m == NULL) {
908 IP6STAT_INC(ip6s_exthdrtoolong);
909 *mp = m;
910 return (-1);
911 }
912 }
913 icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
914 eip6 = (struct ip6_hdr *)(icmp6 + 1);
915 bzero(&icmp6dst, sizeof(icmp6dst));
916
917 /* Detect the upper level protocol */
918 {
919 void (*ctlfunc)(int, struct sockaddr *, void *);
920 u_int8_t nxt = eip6->ip6_nxt;
921 int eoff = off + sizeof(struct icmp6_hdr) +
922 sizeof(struct ip6_hdr);
923 struct ip6ctlparam ip6cp;
924 int icmp6type = icmp6->icmp6_type;
925 struct ip6_frag *fh;
926 struct ip6_rthdr *rth;
927 struct ip6_rthdr0 *rth0;
928 int rthlen;
929
930 while (1) { /* XXX: should avoid infinite loop explicitly? */
931 struct ip6_ext *eh;
932
933 switch (nxt) {
934 case IPPROTO_HOPOPTS:
935 case IPPROTO_DSTOPTS:
936 case IPPROTO_AH:
937 if (m->m_len < eoff + sizeof(struct ip6_ext)) {
938 m = m_pullup(m, eoff +
939 sizeof(struct ip6_ext));
940 if (m == NULL) {
941 IP6STAT_INC(ip6s_exthdrtoolong);
942 *mp = m;
943 return (-1);
944 }
945 }
946 eh = (struct ip6_ext *)
947 (mtod(m, caddr_t) + eoff);
948 if (nxt == IPPROTO_AH)
949 eoff += (eh->ip6e_len + 2) << 2;
950 else
951 eoff += (eh->ip6e_len + 1) << 3;
952 nxt = eh->ip6e_nxt;
953 break;
954 case IPPROTO_ROUTING:
955 /*
956 * When the erroneous packet contains a
957 * routing header, we should examine the
958 * header to determine the final destination.
959 * Otherwise, we can't properly update
960 * information that depends on the final
961 * destination (e.g. path MTU).
962 */
963 if (m->m_len < eoff + sizeof(*rth)) {
964 m = m_pullup(m, eoff + sizeof(*rth));
965 if (m == NULL) {
966 IP6STAT_INC(ip6s_exthdrtoolong);
967 *mp = m;
968 return (-1);
969 }
970 }
971 rth = (struct ip6_rthdr *)
972 (mtod(m, caddr_t) + eoff);
973 rthlen = (rth->ip6r_len + 1) << 3;
974 /*
975 * XXX: currently there is no
976 * officially defined type other
977 * than type-0.
978 * Note that if the segment left field
979 * is 0, all intermediate hops must
980 * have been passed.
981 */
982 if (rth->ip6r_segleft &&
983 rth->ip6r_type == IPV6_RTHDR_TYPE_0) {
984 int hops;
985
986 if (m->m_len < eoff + rthlen) {
987 m = m_pullup(m, eoff + rthlen);
988 if (m == NULL) {
989 IP6STAT_INC(
990 ip6s_exthdrtoolong);
991 *mp = m;
992 return (-1);
993 }
994 }
995 rth0 = (struct ip6_rthdr0 *)
996 (mtod(m, caddr_t) + eoff);
997
998 /* just ignore a bogus header */
999 if ((rth0->ip6r0_len % 2) == 0 &&
1000 (hops = rth0->ip6r0_len/2))
1001 icmp6dst.sin6_addr = *((struct in6_addr *)(rth0 + 1) + (hops - 1));
1002 }
1003 eoff += rthlen;
1004 nxt = rth->ip6r_nxt;
1005 break;
1006 case IPPROTO_FRAGMENT:
1007 if (m->m_len < eoff + sizeof(struct ip6_frag)) {
1008 m = m_pullup(m, eoff +
1009 sizeof(struct ip6_frag));
1010 if (m == NULL) {
1011 IP6STAT_INC(ip6s_exthdrtoolong);
1012 *mp = m;
1013 return (-1);
1014 }
1015 }
1016 fh = (struct ip6_frag *)(mtod(m, caddr_t) +
1017 eoff);
1018 /*
1019 * Data after a fragment header is meaningless
1020 * unless it is the first fragment, but
1021 * we'll go to the notify label for path MTU
1022 * discovery.
1023 */
1024 if (fh->ip6f_offlg & IP6F_OFF_MASK)
1025 goto notify;
1026
1027 eoff += sizeof(struct ip6_frag);
1028 nxt = fh->ip6f_nxt;
1029 break;
1030 default:
1031 /*
1032 * This case includes ESP and the No Next
1033 * Header. In such cases going to the notify
1034 * label does not have any meaning
1035 * (i.e. ctlfunc will be NULL), but we go
1036 * anyway since we might have to update
1037 * path MTU information.
1038 */
1039 goto notify;
1040 }
1041 }
1042 notify:
1043 icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
1044
1045 /*
1046 * retrieve parameters from the inner IPv6 header, and convert
1047 * them into sockaddr structures.
1048 * XXX: there is no guarantee that the source or destination
1049 * addresses of the inner packet are in the same scope as
1050 * the addresses of the icmp packet. But there is no other
1051 * way to determine the zone.
1052 */
1053 eip6 = (struct ip6_hdr *)(icmp6 + 1);
1054
1055 icmp6dst.sin6_len = sizeof(struct sockaddr_in6);
1056 icmp6dst.sin6_family = AF_INET6;
1057 if (IN6_IS_ADDR_UNSPECIFIED(&icmp6dst.sin6_addr))
1058 icmp6dst.sin6_addr = eip6->ip6_dst;
1059 if (in6_setscope(&icmp6dst.sin6_addr, m->m_pkthdr.rcvif, NULL))
1060 goto freeit;
1061 bzero(&icmp6src, sizeof(icmp6src));
1062 icmp6src.sin6_len = sizeof(struct sockaddr_in6);
1063 icmp6src.sin6_family = AF_INET6;
1064 icmp6src.sin6_addr = eip6->ip6_src;
1065 if (in6_setscope(&icmp6src.sin6_addr, m->m_pkthdr.rcvif, NULL))
1066 goto freeit;
1067 icmp6src.sin6_flowinfo =
1068 (eip6->ip6_flow & IPV6_FLOWLABEL_MASK);
1069
1070 ip6cp.ip6c_m = m;
1071 ip6cp.ip6c_icmp6 = icmp6;
1072 ip6cp.ip6c_ip6 = (struct ip6_hdr *)(icmp6 + 1);
1073 ip6cp.ip6c_off = eoff;
1074 ip6cp.ip6c_finaldst = &icmp6dst.sin6_addr;
1075 ip6cp.ip6c_src = &icmp6src;
1076 ip6cp.ip6c_nxt = nxt;
1077
1078 if (icmp6type == ICMP6_PACKET_TOO_BIG) {
1079 notifymtu = ntohl(icmp6->icmp6_mtu);
1080 ip6cp.ip6c_cmdarg = (void *)¬ifymtu;
1081 icmp6_mtudisc_update(&ip6cp, 1); /*XXX*/
1082 }
1083
1084 ctlfunc = (void (*)(int, struct sockaddr *, void *))
1085 (inet6sw[ip6_protox[nxt]].pr_ctlinput);
1086 if (ctlfunc) {
1087 (void) (*ctlfunc)(code, (struct sockaddr *)&icmp6dst,
1088 &ip6cp);
1089 }
1090 }
1091 *mp = m;
1092 return (0);
1093
1094 freeit:
1095 m_freem(m);
1096 *mp = NULL;
1097 return (-1);
1098 }
1099
1100 void
icmp6_mtudisc_update(struct ip6ctlparam * ip6cp,int validated)1101 icmp6_mtudisc_update(struct ip6ctlparam *ip6cp, int validated)
1102 {
1103 struct in6_addr *dst = ip6cp->ip6c_finaldst;
1104 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6;
1105 struct mbuf *m = ip6cp->ip6c_m; /* will be necessary for scope issue */
1106 u_int mtu = ntohl(icmp6->icmp6_mtu);
1107 struct in_conninfo inc;
1108 uint32_t max_mtu;
1109
1110 #if 0
1111 /*
1112 * RFC2460 section 5, last paragraph.
1113 * even though minimum link MTU for IPv6 is IPV6_MMTU,
1114 * we may see ICMPv6 too big with mtu < IPV6_MMTU
1115 * due to packet translator in the middle.
1116 * see ip6_output() and ip6_getpmtu() "alwaysfrag" case for
1117 * special handling.
1118 */
1119 if (mtu < IPV6_MMTU)
1120 return;
1121 #endif
1122
1123 /*
1124 * we reject ICMPv6 too big with abnormally small value.
1125 * XXX what is the good definition of "abnormally small"?
1126 */
1127 if (mtu < sizeof(struct ip6_hdr) + sizeof(struct ip6_frag) + 8)
1128 return;
1129
1130 if (!validated)
1131 return;
1132
1133 /*
1134 * In case the suggested mtu is less than IPV6_MMTU, we
1135 * only need to remember that it was for above mentioned
1136 * "alwaysfrag" case.
1137 * Try to be as close to the spec as possible.
1138 */
1139 if (mtu < IPV6_MMTU)
1140 mtu = IPV6_MMTU - 8;
1141
1142 bzero(&inc, sizeof(inc));
1143 inc.inc_fibnum = M_GETFIB(m);
1144 inc.inc_flags |= INC_ISIPV6;
1145 inc.inc6_faddr = *dst;
1146 if (in6_setscope(&inc.inc6_faddr, m->m_pkthdr.rcvif, NULL))
1147 return;
1148
1149 max_mtu = tcp_hc_getmtu(&inc);
1150 if (max_mtu == 0)
1151 max_mtu = tcp_maxmtu6(&inc, NULL);
1152
1153 if (mtu < max_mtu) {
1154 tcp_hc_updatemtu(&inc, mtu);
1155 ICMP6STAT_INC(icp6s_pmtuchg);
1156 }
1157 }
1158
1159 /*
1160 * Process a Node Information Query packet, based on
1161 * draft-ietf-ipngwg-icmp-name-lookups-07.
1162 *
1163 * Spec incompatibilities:
1164 * - IPv6 Subject address handling
1165 * - IPv4 Subject address handling support missing
1166 * - Proxy reply (answer even if it's not for me)
1167 * - joins NI group address at in6_ifattach() time only, does not cope
1168 * with hostname changes by sethostname(3)
1169 */
1170 static struct mbuf *
ni6_input(struct mbuf * m,int off,struct prison * pr)1171 ni6_input(struct mbuf *m, int off, struct prison *pr)
1172 {
1173 struct icmp6_nodeinfo *ni6, *nni6;
1174 struct mbuf *n = NULL;
1175 u_int16_t qtype;
1176 int subjlen;
1177 int replylen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
1178 struct ni_reply_fqdn *fqdn;
1179 int addrs; /* for NI_QTYPE_NODEADDR */
1180 struct ifnet *ifp = NULL; /* for NI_QTYPE_NODEADDR */
1181 struct in6_addr in6_subj; /* subject address */
1182 struct ip6_hdr *ip6;
1183 int oldfqdn = 0; /* if 1, return pascal string (03 draft) */
1184 char *subj = NULL;
1185 struct in6_ifaddr *ia6 = NULL;
1186
1187 ip6 = mtod(m, struct ip6_hdr *);
1188 ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
1189
1190 /*
1191 * Validate IPv6 source address.
1192 * The default configuration MUST be to refuse answering queries from
1193 * global-scope addresses according to RFC4602.
1194 * Notes:
1195 * - it's not very clear what "refuse" means; this implementation
1196 * simply drops it.
1197 * - it's not very easy to identify global-scope (unicast) addresses
1198 * since there are many prefixes for them. It should be safer
1199 * and in practice sufficient to check "all" but loopback and
1200 * link-local (note that site-local unicast was deprecated and
1201 * ULA is defined as global scope-wise)
1202 */
1203 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_GLOBALOK) == 0 &&
1204 !IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) &&
1205 !IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src))
1206 goto bad;
1207
1208 /*
1209 * Validate IPv6 destination address.
1210 *
1211 * The Responder must discard the Query without further processing
1212 * unless it is one of the Responder's unicast or anycast addresses, or
1213 * a link-local scope multicast address which the Responder has joined.
1214 * [RFC4602, Section 5.]
1215 */
1216 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
1217 if (!IN6_IS_ADDR_MC_LINKLOCAL(&ip6->ip6_dst))
1218 goto bad;
1219 /* else it's a link-local multicast, fine */
1220 } else { /* unicast or anycast */
1221 ia6 = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */, false);
1222 if (ia6 == NULL)
1223 goto bad; /* XXX impossible */
1224
1225 if ((ia6->ia6_flags & IN6_IFF_TEMPORARY) &&
1226 !(V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK)) {
1227 nd6log((LOG_DEBUG, "ni6_input: ignore node info to "
1228 "a temporary address in %s:%d",
1229 __FILE__, __LINE__));
1230 goto bad;
1231 }
1232 }
1233
1234 /* validate query Subject field. */
1235 qtype = ntohs(ni6->ni_qtype);
1236 subjlen = m->m_pkthdr.len - off - sizeof(struct icmp6_nodeinfo);
1237 switch (qtype) {
1238 case NI_QTYPE_NOOP:
1239 case NI_QTYPE_SUPTYPES:
1240 /* 07 draft */
1241 if (ni6->ni_code == ICMP6_NI_SUBJ_FQDN && subjlen == 0)
1242 break;
1243 /* FALLTHROUGH */
1244 case NI_QTYPE_FQDN:
1245 case NI_QTYPE_NODEADDR:
1246 case NI_QTYPE_IPV4ADDR:
1247 switch (ni6->ni_code) {
1248 case ICMP6_NI_SUBJ_IPV6:
1249 #if ICMP6_NI_SUBJ_IPV6 != 0
1250 case 0:
1251 #endif
1252 /*
1253 * backward compatibility - try to accept 03 draft
1254 * format, where no Subject is present.
1255 */
1256 if (qtype == NI_QTYPE_FQDN && ni6->ni_code == 0 &&
1257 subjlen == 0) {
1258 oldfqdn++;
1259 break;
1260 }
1261 #if ICMP6_NI_SUBJ_IPV6 != 0
1262 if (ni6->ni_code != ICMP6_NI_SUBJ_IPV6)
1263 goto bad;
1264 #endif
1265
1266 if (subjlen != sizeof(struct in6_addr))
1267 goto bad;
1268
1269 /*
1270 * Validate Subject address.
1271 *
1272 * Not sure what exactly "address belongs to the node"
1273 * means in the spec, is it just unicast, or what?
1274 *
1275 * At this moment we consider Subject address as
1276 * "belong to the node" if the Subject address equals
1277 * to the IPv6 destination address; validation for
1278 * IPv6 destination address should have done enough
1279 * check for us.
1280 *
1281 * We do not do proxy at this moment.
1282 */
1283 m_copydata(m, off + sizeof(struct icmp6_nodeinfo),
1284 subjlen, (caddr_t)&in6_subj);
1285 if (in6_setscope(&in6_subj, m->m_pkthdr.rcvif, NULL))
1286 goto bad;
1287
1288 subj = (char *)&in6_subj;
1289 if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &in6_subj))
1290 break;
1291
1292 /*
1293 * XXX if we are to allow other cases, we should really
1294 * be careful about scope here.
1295 * basically, we should disallow queries toward IPv6
1296 * destination X with subject Y,
1297 * if scope(X) > scope(Y).
1298 * if we allow scope(X) > scope(Y), it will result in
1299 * information leakage across scope boundary.
1300 */
1301 goto bad;
1302
1303 case ICMP6_NI_SUBJ_FQDN:
1304 /*
1305 * Validate Subject name with gethostname(3).
1306 *
1307 * The behavior may need some debate, since:
1308 * - we are not sure if the node has FQDN as
1309 * hostname (returned by gethostname(3)).
1310 * - the code does wildcard match for truncated names.
1311 * however, we are not sure if we want to perform
1312 * wildcard match, if gethostname(3) side has
1313 * truncated hostname.
1314 */
1315 mtx_lock(&pr->pr_mtx);
1316 n = ni6_nametodns(pr->pr_hostname,
1317 strlen(pr->pr_hostname), 0);
1318 mtx_unlock(&pr->pr_mtx);
1319 if (!n || n->m_next || n->m_len == 0)
1320 goto bad;
1321 if (m->m_len < off + sizeof(struct icmp6_nodeinfo) +
1322 subjlen) {
1323 m = m_pullup(m, off +
1324 sizeof(struct icmp6_nodeinfo) + subjlen);
1325 if (m == NULL) {
1326 IP6STAT_INC(ip6s_exthdrtoolong);
1327 goto bad;
1328 }
1329 }
1330 /* ip6 possibly invalid but not used after. */
1331 ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
1332 subj = (char *)(mtod(m, caddr_t) + off +
1333 sizeof(struct icmp6_nodeinfo));
1334 if (!ni6_dnsmatch(subj, subjlen, mtod(n, const char *),
1335 n->m_len)) {
1336 goto bad;
1337 }
1338 m_freem(n);
1339 n = NULL;
1340 break;
1341
1342 case ICMP6_NI_SUBJ_IPV4: /* XXX: to be implemented? */
1343 default:
1344 goto bad;
1345 }
1346 break;
1347 }
1348
1349 /* refuse based on configuration. XXX ICMP6_NI_REFUSED? */
1350 switch (qtype) {
1351 case NI_QTYPE_FQDN:
1352 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_FQDNOK) == 0)
1353 goto bad;
1354 break;
1355 case NI_QTYPE_NODEADDR:
1356 case NI_QTYPE_IPV4ADDR:
1357 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_NODEADDROK) == 0)
1358 goto bad;
1359 break;
1360 }
1361
1362 /* guess reply length */
1363 switch (qtype) {
1364 case NI_QTYPE_NOOP:
1365 break; /* no reply data */
1366 case NI_QTYPE_SUPTYPES:
1367 replylen += sizeof(u_int32_t);
1368 break;
1369 case NI_QTYPE_FQDN:
1370 /* XXX will append an mbuf */
1371 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
1372 break;
1373 case NI_QTYPE_NODEADDR:
1374 addrs = ni6_addrs(ni6, m, &ifp, (struct in6_addr *)subj);
1375 if ((replylen += addrs * (sizeof(struct in6_addr) +
1376 sizeof(u_int32_t))) > MCLBYTES)
1377 replylen = MCLBYTES; /* XXX: will truncate pkt later */
1378 break;
1379 case NI_QTYPE_IPV4ADDR:
1380 /* unsupported - should respond with unknown Qtype? */
1381 break;
1382 default:
1383 /*
1384 * XXX: We must return a reply with the ICMP6 code
1385 * `unknown Qtype' in this case. However we regard the case
1386 * as an FQDN query for backward compatibility.
1387 * Older versions set a random value to this field,
1388 * so it rarely varies in the defined qtypes.
1389 * But the mechanism is not reliable...
1390 * maybe we should obsolete older versions.
1391 */
1392 qtype = NI_QTYPE_FQDN;
1393 /* XXX will append an mbuf */
1394 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
1395 oldfqdn++;
1396 break;
1397 }
1398
1399 /* Allocate an mbuf to reply. */
1400 if (replylen > MCLBYTES) {
1401 /*
1402 * XXX: should we try to allocate more? But MCLBYTES
1403 * is probably much larger than IPV6_MMTU...
1404 */
1405 goto bad;
1406 }
1407 if (replylen > MHLEN)
1408 n = m_getcl(M_NOWAIT, m->m_type, M_PKTHDR);
1409 else
1410 n = m_gethdr(M_NOWAIT, m->m_type);
1411 if (n == NULL) {
1412 m_freem(m);
1413 return (NULL);
1414 }
1415 m_move_pkthdr(n, m); /* just for recvif and FIB */
1416 n->m_pkthdr.len = n->m_len = replylen;
1417
1418 /* copy mbuf header and IPv6 + Node Information base headers */
1419 bcopy(mtod(m, caddr_t), mtod(n, caddr_t), sizeof(struct ip6_hdr));
1420 nni6 = (struct icmp6_nodeinfo *)(mtod(n, struct ip6_hdr *) + 1);
1421 bcopy((caddr_t)ni6, (caddr_t)nni6, sizeof(struct icmp6_nodeinfo));
1422
1423 /* qtype dependent procedure */
1424 switch (qtype) {
1425 case NI_QTYPE_NOOP:
1426 nni6->ni_code = ICMP6_NI_SUCCESS;
1427 nni6->ni_flags = 0;
1428 break;
1429 case NI_QTYPE_SUPTYPES:
1430 {
1431 u_int32_t v;
1432 nni6->ni_code = ICMP6_NI_SUCCESS;
1433 nni6->ni_flags = htons(0x0000); /* raw bitmap */
1434 /* supports NOOP, SUPTYPES, FQDN, and NODEADDR */
1435 v = (u_int32_t)htonl(0x0000000f);
1436 bcopy(&v, nni6 + 1, sizeof(u_int32_t));
1437 break;
1438 }
1439 case NI_QTYPE_FQDN:
1440 nni6->ni_code = ICMP6_NI_SUCCESS;
1441 fqdn = (struct ni_reply_fqdn *)(mtod(n, caddr_t) +
1442 sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo));
1443 nni6->ni_flags = 0; /* XXX: meaningless TTL */
1444 fqdn->ni_fqdn_ttl = 0; /* ditto. */
1445 /*
1446 * XXX do we really have FQDN in hostname?
1447 */
1448 mtx_lock(&pr->pr_mtx);
1449 n->m_next = ni6_nametodns(pr->pr_hostname,
1450 strlen(pr->pr_hostname), oldfqdn);
1451 mtx_unlock(&pr->pr_mtx);
1452 if (n->m_next == NULL)
1453 goto bad;
1454 /* XXX we assume that n->m_next is not a chain */
1455 if (n->m_next->m_next != NULL)
1456 goto bad;
1457 n->m_pkthdr.len += n->m_next->m_len;
1458 break;
1459 case NI_QTYPE_NODEADDR:
1460 {
1461 int lenlim, copied;
1462
1463 nni6->ni_code = ICMP6_NI_SUCCESS;
1464 n->m_pkthdr.len = n->m_len =
1465 sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
1466 lenlim = M_TRAILINGSPACE(n);
1467 copied = ni6_store_addrs(ni6, nni6, ifp, lenlim);
1468 /* XXX: reset mbuf length */
1469 n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
1470 sizeof(struct icmp6_nodeinfo) + copied;
1471 break;
1472 }
1473 default:
1474 break; /* XXX impossible! */
1475 }
1476
1477 nni6->ni_type = ICMP6_NI_REPLY;
1478 m_freem(m);
1479 return (n);
1480
1481 bad:
1482 m_freem(m);
1483 if (n)
1484 m_freem(n);
1485 return (NULL);
1486 }
1487
1488 /*
1489 * make a mbuf with DNS-encoded string. no compression support.
1490 *
1491 * XXX names with less than 2 dots (like "foo" or "foo.section") will be
1492 * treated as truncated name (two \0 at the end). this is a wild guess.
1493 *
1494 * old - return pascal string if non-zero
1495 */
1496 static struct mbuf *
ni6_nametodns(const char * name,int namelen,int old)1497 ni6_nametodns(const char *name, int namelen, int old)
1498 {
1499 struct mbuf *m;
1500 char *cp, *ep;
1501 const char *p, *q;
1502 int i, len, nterm;
1503
1504 if (old)
1505 len = namelen + 1;
1506 else
1507 len = MCLBYTES;
1508
1509 /* Because MAXHOSTNAMELEN is usually 256, we use cluster mbuf. */
1510 if (len > MLEN)
1511 m = m_getcl(M_NOWAIT, MT_DATA, 0);
1512 else
1513 m = m_get(M_NOWAIT, MT_DATA);
1514 if (m == NULL)
1515 goto fail;
1516
1517 if (old) {
1518 m->m_len = len;
1519 *mtod(m, char *) = namelen;
1520 bcopy(name, mtod(m, char *) + 1, namelen);
1521 return m;
1522 } else {
1523 m->m_len = 0;
1524 cp = mtod(m, char *);
1525 ep = mtod(m, char *) + M_TRAILINGSPACE(m);
1526
1527 /* if not certain about my name, return empty buffer */
1528 if (namelen == 0)
1529 return m;
1530
1531 /*
1532 * guess if it looks like shortened hostname, or FQDN.
1533 * shortened hostname needs two trailing "\0".
1534 */
1535 i = 0;
1536 for (p = name; p < name + namelen; p++) {
1537 if (*p && *p == '.')
1538 i++;
1539 }
1540 if (i < 2)
1541 nterm = 2;
1542 else
1543 nterm = 1;
1544
1545 p = name;
1546 while (cp < ep && p < name + namelen) {
1547 i = 0;
1548 for (q = p; q < name + namelen && *q && *q != '.'; q++)
1549 i++;
1550 /* result does not fit into mbuf */
1551 if (cp + i + 1 >= ep)
1552 goto fail;
1553 /*
1554 * DNS label length restriction, RFC1035 page 8.
1555 * "i == 0" case is included here to avoid returning
1556 * 0-length label on "foo..bar".
1557 */
1558 if (i <= 0 || i >= 64)
1559 goto fail;
1560 *cp++ = i;
1561 bcopy(p, cp, i);
1562 cp += i;
1563 p = q;
1564 if (p < name + namelen && *p == '.')
1565 p++;
1566 }
1567 /* termination */
1568 if (cp + nterm >= ep)
1569 goto fail;
1570 while (nterm-- > 0)
1571 *cp++ = '\0';
1572 m->m_len = cp - mtod(m, char *);
1573 return m;
1574 }
1575
1576 panic("should not reach here");
1577 /* NOTREACHED */
1578
1579 fail:
1580 if (m)
1581 m_freem(m);
1582 return NULL;
1583 }
1584
1585 /*
1586 * check if two DNS-encoded string matches. takes care of truncated
1587 * form (with \0\0 at the end). no compression support.
1588 * XXX upper/lowercase match (see RFC2065)
1589 */
1590 static int
ni6_dnsmatch(const char * a,int alen,const char * b,int blen)1591 ni6_dnsmatch(const char *a, int alen, const char *b, int blen)
1592 {
1593 const char *a0, *b0;
1594 int l;
1595
1596 /* simplest case - need validation? */
1597 if (alen == blen && bcmp(a, b, alen) == 0)
1598 return 1;
1599
1600 a0 = a;
1601 b0 = b;
1602
1603 /* termination is mandatory */
1604 if (alen < 2 || blen < 2)
1605 return 0;
1606 if (a0[alen - 1] != '\0' || b0[blen - 1] != '\0')
1607 return 0;
1608 alen--;
1609 blen--;
1610
1611 while (a - a0 < alen && b - b0 < blen) {
1612 if (a - a0 + 1 > alen || b - b0 + 1 > blen)
1613 return 0;
1614
1615 if ((signed char)a[0] < 0 || (signed char)b[0] < 0)
1616 return 0;
1617 /* we don't support compression yet */
1618 if (a[0] >= 64 || b[0] >= 64)
1619 return 0;
1620
1621 /* truncated case */
1622 if (a[0] == 0 && a - a0 == alen - 1)
1623 return 1;
1624 if (b[0] == 0 && b - b0 == blen - 1)
1625 return 1;
1626 if (a[0] == 0 || b[0] == 0)
1627 return 0;
1628
1629 if (a[0] != b[0])
1630 return 0;
1631 l = a[0];
1632 if (a - a0 + 1 + l > alen || b - b0 + 1 + l > blen)
1633 return 0;
1634 if (bcmp(a + 1, b + 1, l) != 0)
1635 return 0;
1636
1637 a += 1 + l;
1638 b += 1 + l;
1639 }
1640
1641 if (a - a0 == alen && b - b0 == blen)
1642 return 1;
1643 else
1644 return 0;
1645 }
1646
1647 /*
1648 * calculate the number of addresses to be returned in the node info reply.
1649 */
1650 static int
ni6_addrs(struct icmp6_nodeinfo * ni6,struct mbuf * m,struct ifnet ** ifpp,struct in6_addr * subj)1651 ni6_addrs(struct icmp6_nodeinfo *ni6, struct mbuf *m, struct ifnet **ifpp,
1652 struct in6_addr *subj)
1653 {
1654 struct ifnet *ifp;
1655 struct in6_ifaddr *ifa6;
1656 struct ifaddr *ifa;
1657 int addrs = 0, addrsofif, iffound = 0;
1658 int niflags = ni6->ni_flags;
1659
1660 NET_EPOCH_ASSERT();
1661
1662 if ((niflags & NI_NODEADDR_FLAG_ALL) == 0) {
1663 switch (ni6->ni_code) {
1664 case ICMP6_NI_SUBJ_IPV6:
1665 if (subj == NULL) /* must be impossible... */
1666 return (0);
1667 break;
1668 default:
1669 /*
1670 * XXX: we only support IPv6 subject address for
1671 * this Qtype.
1672 */
1673 return (0);
1674 }
1675 }
1676
1677 CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
1678 addrsofif = 0;
1679 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1680 if (ifa->ifa_addr->sa_family != AF_INET6)
1681 continue;
1682 ifa6 = (struct in6_ifaddr *)ifa;
1683
1684 if ((niflags & NI_NODEADDR_FLAG_ALL) == 0 &&
1685 IN6_ARE_ADDR_EQUAL(subj, &ifa6->ia_addr.sin6_addr))
1686 iffound = 1;
1687
1688 /*
1689 * IPv4-mapped addresses can only be returned by a
1690 * Node Information proxy, since they represent
1691 * addresses of IPv4-only nodes, which perforce do
1692 * not implement this protocol.
1693 * [icmp-name-lookups-07, Section 5.4]
1694 * So we don't support NI_NODEADDR_FLAG_COMPAT in
1695 * this function at this moment.
1696 */
1697
1698 /* What do we have to do about ::1? */
1699 switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1700 case IPV6_ADDR_SCOPE_LINKLOCAL:
1701 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
1702 continue;
1703 break;
1704 case IPV6_ADDR_SCOPE_SITELOCAL:
1705 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
1706 continue;
1707 break;
1708 case IPV6_ADDR_SCOPE_GLOBAL:
1709 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
1710 continue;
1711 break;
1712 default:
1713 continue;
1714 }
1715
1716 /*
1717 * check if anycast is okay.
1718 * XXX: just experimental. not in the spec.
1719 */
1720 if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
1721 (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
1722 continue; /* we need only unicast addresses */
1723 if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
1724 (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
1725 continue;
1726 }
1727 addrsofif++; /* count the address */
1728 }
1729 if (iffound) {
1730 *ifpp = ifp;
1731 return (addrsofif);
1732 }
1733
1734 addrs += addrsofif;
1735 }
1736
1737 return (addrs);
1738 }
1739
1740 static int
ni6_store_addrs(struct icmp6_nodeinfo * ni6,struct icmp6_nodeinfo * nni6,struct ifnet * ifp0,int resid)1741 ni6_store_addrs(struct icmp6_nodeinfo *ni6, struct icmp6_nodeinfo *nni6,
1742 struct ifnet *ifp0, int resid)
1743 {
1744 struct ifnet *ifp;
1745 struct in6_ifaddr *ifa6;
1746 struct ifaddr *ifa;
1747 struct ifnet *ifp_dep = NULL;
1748 int copied = 0, allow_deprecated = 0;
1749 u_char *cp = (u_char *)(nni6 + 1);
1750 int niflags = ni6->ni_flags;
1751 u_int32_t ltime;
1752
1753 NET_EPOCH_ASSERT();
1754
1755 if (ifp0 == NULL && !(niflags & NI_NODEADDR_FLAG_ALL))
1756 return (0); /* needless to copy */
1757
1758 ifp = ifp0 ? ifp0 : CK_STAILQ_FIRST(&V_ifnet);
1759 again:
1760
1761 for (; ifp; ifp = CK_STAILQ_NEXT(ifp, if_link)) {
1762 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1763 if (ifa->ifa_addr->sa_family != AF_INET6)
1764 continue;
1765 ifa6 = (struct in6_ifaddr *)ifa;
1766
1767 if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) != 0 &&
1768 allow_deprecated == 0) {
1769 /*
1770 * prefererred address should be put before
1771 * deprecated addresses.
1772 */
1773
1774 /* record the interface for later search */
1775 if (ifp_dep == NULL)
1776 ifp_dep = ifp;
1777
1778 continue;
1779 } else if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) == 0 &&
1780 allow_deprecated != 0)
1781 continue; /* we now collect deprecated addrs */
1782
1783 /* What do we have to do about ::1? */
1784 switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1785 case IPV6_ADDR_SCOPE_LINKLOCAL:
1786 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
1787 continue;
1788 break;
1789 case IPV6_ADDR_SCOPE_SITELOCAL:
1790 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
1791 continue;
1792 break;
1793 case IPV6_ADDR_SCOPE_GLOBAL:
1794 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
1795 continue;
1796 break;
1797 default:
1798 continue;
1799 }
1800
1801 /*
1802 * check if anycast is okay.
1803 * XXX: just experimental. not in the spec.
1804 */
1805 if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
1806 (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
1807 continue;
1808 if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
1809 (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
1810 continue;
1811 }
1812
1813 /* now we can copy the address */
1814 if (resid < sizeof(struct in6_addr) +
1815 sizeof(u_int32_t)) {
1816 /*
1817 * We give up much more copy.
1818 * Set the truncate flag and return.
1819 */
1820 nni6->ni_flags |= NI_NODEADDR_FLAG_TRUNCATE;
1821 return (copied);
1822 }
1823
1824 /*
1825 * Set the TTL of the address.
1826 * The TTL value should be one of the following
1827 * according to the specification:
1828 *
1829 * 1. The remaining lifetime of a DHCP lease on the
1830 * address, or
1831 * 2. The remaining Valid Lifetime of a prefix from
1832 * which the address was derived through Stateless
1833 * Autoconfiguration.
1834 *
1835 * Note that we currently do not support stateful
1836 * address configuration by DHCPv6, so the former
1837 * case can't happen.
1838 */
1839 if (ifa6->ia6_lifetime.ia6t_expire == 0)
1840 ltime = ND6_INFINITE_LIFETIME;
1841 else {
1842 if (ifa6->ia6_lifetime.ia6t_expire >
1843 time_uptime)
1844 ltime = htonl(ifa6->ia6_lifetime.ia6t_expire - time_uptime);
1845 else
1846 ltime = 0;
1847 }
1848
1849 bcopy(<ime, cp, sizeof(u_int32_t));
1850 cp += sizeof(u_int32_t);
1851
1852 /* copy the address itself */
1853 bcopy(&ifa6->ia_addr.sin6_addr, cp,
1854 sizeof(struct in6_addr));
1855 in6_clearscope((struct in6_addr *)cp); /* XXX */
1856 cp += sizeof(struct in6_addr);
1857
1858 resid -= (sizeof(struct in6_addr) + sizeof(u_int32_t));
1859 copied += (sizeof(struct in6_addr) + sizeof(u_int32_t));
1860 }
1861 if (ifp0) /* we need search only on the specified IF */
1862 break;
1863 }
1864
1865 if (allow_deprecated == 0 && ifp_dep != NULL) {
1866 ifp = ifp_dep;
1867 allow_deprecated = 1;
1868
1869 goto again;
1870 }
1871
1872 return (copied);
1873 }
1874
1875 /*
1876 * XXX almost dup'ed code with rip6_input.
1877 */
1878 static int
icmp6_rip6_input(struct mbuf ** mp,int off)1879 icmp6_rip6_input(struct mbuf **mp, int off)
1880 {
1881 struct mbuf *m = *mp;
1882 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1883 struct inpcb *inp;
1884 struct inpcb *last = NULL;
1885 struct sockaddr_in6 fromsa;
1886 struct icmp6_hdr *icmp6;
1887 struct mbuf *opts = NULL;
1888
1889 NET_EPOCH_ASSERT();
1890
1891 /* This is assumed to be safe; icmp6_input() does a pullup. */
1892 icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
1893
1894 /*
1895 * XXX: the address may have embedded scope zone ID, which should be
1896 * hidden from applications.
1897 */
1898 bzero(&fromsa, sizeof(fromsa));
1899 fromsa.sin6_family = AF_INET6;
1900 fromsa.sin6_len = sizeof(struct sockaddr_in6);
1901 fromsa.sin6_addr = ip6->ip6_src;
1902 if (sa6_recoverscope(&fromsa)) {
1903 m_freem(m);
1904 *mp = NULL;
1905 return (IPPROTO_DONE);
1906 }
1907
1908 CK_LIST_FOREACH(inp, &V_ripcb, inp_list) {
1909 if ((inp->inp_vflag & INP_IPV6) == 0)
1910 continue;
1911 if (inp->inp_ip_p != IPPROTO_ICMPV6)
1912 continue;
1913 if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) &&
1914 !IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr, &ip6->ip6_dst))
1915 continue;
1916 if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr) &&
1917 !IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr, &ip6->ip6_src))
1918 continue;
1919 INP_RLOCK(inp);
1920 if (__predict_false(inp->inp_flags2 & INP_FREED)) {
1921 INP_RUNLOCK(inp);
1922 continue;
1923 }
1924 if (ICMP6_FILTER_WILLBLOCK(icmp6->icmp6_type,
1925 inp->in6p_icmp6filt)) {
1926 INP_RUNLOCK(inp);
1927 continue;
1928 }
1929 if (last != NULL) {
1930 struct mbuf *n = NULL;
1931
1932 /*
1933 * Recent network drivers tend to allocate a single
1934 * mbuf cluster, rather than to make a couple of
1935 * mbufs without clusters. Also, since the IPv6 code
1936 * path tries to avoid m_pullup(), it is highly
1937 * probable that we still have an mbuf cluster here
1938 * even though the necessary length can be stored in an
1939 * mbuf's internal buffer.
1940 * Meanwhile, the default size of the receive socket
1941 * buffer for raw sockets is not so large. This means
1942 * the possibility of packet loss is relatively higher
1943 * than before. To avoid this scenario, we copy the
1944 * received data to a separate mbuf that does not use
1945 * a cluster, if possible.
1946 * XXX: it is better to copy the data after stripping
1947 * intermediate headers.
1948 */
1949 if ((m->m_flags & M_EXT) && m->m_next == NULL &&
1950 m->m_len <= MHLEN) {
1951 n = m_get(M_NOWAIT, m->m_type);
1952 if (n != NULL) {
1953 if (m_dup_pkthdr(n, m, M_NOWAIT)) {
1954 bcopy(m->m_data, n->m_data,
1955 m->m_len);
1956 n->m_len = m->m_len;
1957 } else {
1958 m_free(n);
1959 n = NULL;
1960 }
1961 }
1962 }
1963 if (n != NULL ||
1964 (n = m_copym(m, 0, M_COPYALL, M_NOWAIT)) != NULL) {
1965 if (last->inp_flags & INP_CONTROLOPTS)
1966 ip6_savecontrol(last, n, &opts);
1967 /* strip intermediate headers */
1968 m_adj(n, off);
1969 SOCKBUF_LOCK(&last->inp_socket->so_rcv);
1970 if (sbappendaddr_locked(
1971 &last->inp_socket->so_rcv,
1972 (struct sockaddr *)&fromsa, n, opts)
1973 == 0) {
1974 soroverflow_locked(last->inp_socket);
1975 m_freem(n);
1976 if (opts) {
1977 m_freem(opts);
1978 }
1979 } else
1980 sorwakeup_locked(last->inp_socket);
1981 opts = NULL;
1982 }
1983 INP_RUNLOCK(last);
1984 }
1985 last = inp;
1986 }
1987 if (last != NULL) {
1988 if (last->inp_flags & INP_CONTROLOPTS)
1989 ip6_savecontrol(last, m, &opts);
1990 /* strip intermediate headers */
1991 m_adj(m, off);
1992
1993 /* avoid using mbuf clusters if possible (see above) */
1994 if ((m->m_flags & M_EXT) && m->m_next == NULL &&
1995 m->m_len <= MHLEN) {
1996 struct mbuf *n;
1997
1998 n = m_get(M_NOWAIT, m->m_type);
1999 if (n != NULL) {
2000 if (m_dup_pkthdr(n, m, M_NOWAIT)) {
2001 bcopy(m->m_data, n->m_data, m->m_len);
2002 n->m_len = m->m_len;
2003
2004 m_freem(m);
2005 m = n;
2006 } else {
2007 m_freem(n);
2008 n = NULL;
2009 }
2010 }
2011 }
2012 SOCKBUF_LOCK(&last->inp_socket->so_rcv);
2013 if (sbappendaddr_locked(&last->inp_socket->so_rcv,
2014 (struct sockaddr *)&fromsa, m, opts) == 0) {
2015 m_freem(m);
2016 if (opts)
2017 m_freem(opts);
2018 soroverflow_locked(last->inp_socket);
2019 } else
2020 sorwakeup_locked(last->inp_socket);
2021 INP_RUNLOCK(last);
2022 } else {
2023 m_freem(m);
2024 IP6STAT_DEC(ip6s_delivered);
2025 }
2026 *mp = NULL;
2027 return (IPPROTO_DONE);
2028 }
2029
2030 /*
2031 * Reflect the ip6 packet back to the source.
2032 * OFF points to the icmp6 header, counted from the top of the mbuf.
2033 */
2034 static void
icmp6_reflect(struct mbuf * m,size_t off)2035 icmp6_reflect(struct mbuf *m, size_t off)
2036 {
2037 struct in6_addr src6, *srcp;
2038 struct ip6_hdr *ip6;
2039 struct icmp6_hdr *icmp6;
2040 struct in6_ifaddr *ia = NULL;
2041 struct ifnet *outif = NULL;
2042 int plen;
2043 int type, code, hlim;
2044
2045 /* too short to reflect */
2046 if (off < sizeof(struct ip6_hdr)) {
2047 nd6log((LOG_DEBUG,
2048 "sanity fail: off=%lx, sizeof(ip6)=%lx in %s:%d\n",
2049 (u_long)off, (u_long)sizeof(struct ip6_hdr),
2050 __FILE__, __LINE__));
2051 goto bad;
2052 }
2053
2054 /*
2055 * If there are extra headers between IPv6 and ICMPv6, strip
2056 * off that header first.
2057 */
2058 #ifdef DIAGNOSTIC
2059 if (sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) > MHLEN)
2060 panic("assumption failed in icmp6_reflect");
2061 #endif
2062 if (off > sizeof(struct ip6_hdr)) {
2063 size_t l;
2064 struct ip6_hdr nip6;
2065
2066 l = off - sizeof(struct ip6_hdr);
2067 m_copydata(m, 0, sizeof(nip6), (caddr_t)&nip6);
2068 m_adj(m, l);
2069 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
2070 if (m->m_len < l) {
2071 if ((m = m_pullup(m, l)) == NULL)
2072 return;
2073 }
2074 bcopy((caddr_t)&nip6, mtod(m, caddr_t), sizeof(nip6));
2075 } else /* off == sizeof(struct ip6_hdr) */ {
2076 size_t l;
2077 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
2078 if (m->m_len < l) {
2079 if ((m = m_pullup(m, l)) == NULL)
2080 return;
2081 }
2082 }
2083 plen = m->m_pkthdr.len - sizeof(struct ip6_hdr);
2084 ip6 = mtod(m, struct ip6_hdr *);
2085 ip6->ip6_nxt = IPPROTO_ICMPV6;
2086 icmp6 = (struct icmp6_hdr *)(ip6 + 1);
2087 type = icmp6->icmp6_type; /* keep type for statistics */
2088 code = icmp6->icmp6_code; /* ditto. */
2089 hlim = 0;
2090 srcp = NULL;
2091
2092 /*
2093 * If the incoming packet was addressed directly to us (i.e. unicast),
2094 * use dst as the src for the reply.
2095 * The IN6_IFF_NOTREADY case should be VERY rare, but is possible
2096 * (for example) when we encounter an error while forwarding procedure
2097 * destined to a duplicated address of ours.
2098 */
2099 if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
2100 ia = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */, false);
2101 if (ia != NULL && !(ia->ia6_flags &
2102 (IN6_IFF_ANYCAST|IN6_IFF_NOTREADY))) {
2103 src6 = ia->ia_addr.sin6_addr;
2104 srcp = &src6;
2105
2106 if (m->m_pkthdr.rcvif != NULL) {
2107 /* XXX: This may not be the outgoing interface */
2108 hlim = ND_IFINFO(m->m_pkthdr.rcvif)->chlim;
2109 } else
2110 hlim = V_ip6_defhlim;
2111 }
2112 }
2113
2114 if (srcp == NULL) {
2115 int error;
2116 struct in6_addr dst6;
2117 uint32_t scopeid;
2118
2119 /*
2120 * This case matches to multicasts, our anycast, or unicasts
2121 * that we do not own. Select a source address based on the
2122 * source address of the erroneous packet.
2123 */
2124 in6_splitscope(&ip6->ip6_src, &dst6, &scopeid);
2125 error = in6_selectsrc_addr(M_GETFIB(m), &dst6,
2126 scopeid, NULL, &src6, &hlim);
2127
2128 if (error) {
2129 char ip6buf[INET6_ADDRSTRLEN];
2130 nd6log((LOG_DEBUG,
2131 "icmp6_reflect: source can't be determined: "
2132 "dst=%s, error=%d\n",
2133 ip6_sprintf(ip6buf, &ip6->ip6_dst), error));
2134 goto bad;
2135 }
2136 srcp = &src6;
2137 }
2138 /*
2139 * ip6_input() drops a packet if its src is multicast.
2140 * So, the src is never multicast.
2141 */
2142 ip6->ip6_dst = ip6->ip6_src;
2143 ip6->ip6_src = *srcp;
2144 ip6->ip6_flow = 0;
2145 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
2146 ip6->ip6_vfc |= IPV6_VERSION;
2147 ip6->ip6_nxt = IPPROTO_ICMPV6;
2148 ip6->ip6_hlim = hlim;
2149
2150 icmp6->icmp6_cksum = 0;
2151 icmp6->icmp6_cksum = in6_cksum(m, IPPROTO_ICMPV6,
2152 sizeof(struct ip6_hdr), plen);
2153
2154 /*
2155 * XXX option handling
2156 */
2157
2158 m->m_flags &= ~(M_BCAST|M_MCAST);
2159 m->m_pkthdr.rcvif = NULL;
2160 ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
2161 if (outif)
2162 icmp6_ifoutstat_inc(outif, type, code);
2163
2164 return;
2165
2166 bad:
2167 m_freem(m);
2168 return;
2169 }
2170
2171 void
icmp6_fasttimo(void)2172 icmp6_fasttimo(void)
2173 {
2174
2175 mld_fasttimo();
2176 }
2177
2178 void
icmp6_slowtimo(void)2179 icmp6_slowtimo(void)
2180 {
2181
2182 mld_slowtimo();
2183 }
2184
2185 static const char *
icmp6_redirect_diag(struct in6_addr * src6,struct in6_addr * dst6,struct in6_addr * tgt6)2186 icmp6_redirect_diag(struct in6_addr *src6, struct in6_addr *dst6,
2187 struct in6_addr *tgt6)
2188 {
2189 static char buf[1024];
2190 char ip6bufs[INET6_ADDRSTRLEN];
2191 char ip6bufd[INET6_ADDRSTRLEN];
2192 char ip6buft[INET6_ADDRSTRLEN];
2193 snprintf(buf, sizeof(buf), "(src=%s dst=%s tgt=%s)",
2194 ip6_sprintf(ip6bufs, src6), ip6_sprintf(ip6bufd, dst6),
2195 ip6_sprintf(ip6buft, tgt6));
2196 return buf;
2197 }
2198
2199 void
icmp6_redirect_input(struct mbuf * m,int off)2200 icmp6_redirect_input(struct mbuf *m, int off)
2201 {
2202 struct ifnet *ifp;
2203 struct ip6_hdr *ip6;
2204 struct nd_redirect *nd_rd;
2205 struct in6_addr src6, redtgt6, reddst6;
2206 union nd_opts ndopts;
2207 char ip6buf[INET6_ADDRSTRLEN];
2208 char *lladdr;
2209 int icmp6len, is_onlink, is_router, lladdrlen;
2210
2211 M_ASSERTPKTHDR(m);
2212 KASSERT(m->m_pkthdr.rcvif != NULL, ("%s: no rcvif", __func__));
2213
2214 /* XXX if we are router, we don't update route by icmp6 redirect */
2215 if (V_ip6_forwarding)
2216 goto freeit;
2217 if (!V_icmp6_rediraccept)
2218 goto freeit;
2219
2220 /* RFC 6980: Nodes MUST silently ignore fragments */
2221 if(m->m_flags & M_FRAGMENTED)
2222 goto freeit;
2223
2224 ip6 = mtod(m, struct ip6_hdr *);
2225 icmp6len = ntohs(ip6->ip6_plen);
2226 if (m->m_len < off + icmp6len) {
2227 m = m_pullup(m, off + icmp6len);
2228 if (m == NULL) {
2229 IP6STAT_INC(ip6s_exthdrtoolong);
2230 return;
2231 }
2232 }
2233 ip6 = mtod(m, struct ip6_hdr *);
2234 nd_rd = (struct nd_redirect *)((caddr_t)ip6 + off);
2235
2236 ifp = m->m_pkthdr.rcvif;
2237 redtgt6 = nd_rd->nd_rd_target;
2238 reddst6 = nd_rd->nd_rd_dst;
2239
2240 if (in6_setscope(&redtgt6, ifp, NULL) ||
2241 in6_setscope(&reddst6, ifp, NULL)) {
2242 goto freeit;
2243 }
2244
2245 /* validation */
2246 src6 = ip6->ip6_src;
2247 if (!IN6_IS_ADDR_LINKLOCAL(&src6)) {
2248 nd6log((LOG_ERR,
2249 "ICMP6 redirect sent from %s rejected; "
2250 "must be from linklocal\n",
2251 ip6_sprintf(ip6buf, &src6)));
2252 goto bad;
2253 }
2254 if (__predict_false(ip6->ip6_hlim != 255)) {
2255 ICMP6STAT_INC(icp6s_invlhlim);
2256 nd6log((LOG_ERR,
2257 "ICMP6 redirect sent from %s rejected; "
2258 "hlim=%d (must be 255)\n",
2259 ip6_sprintf(ip6buf, &src6), ip6->ip6_hlim));
2260 goto bad;
2261 }
2262 {
2263 /* ip6->ip6_src must be equal to gw for icmp6->icmp6_reddst */
2264 struct nhop_object *nh;
2265 struct in6_addr kdst;
2266 uint32_t scopeid;
2267
2268 in6_splitscope(&reddst6, &kdst, &scopeid);
2269 NET_EPOCH_ASSERT();
2270 nh = fib6_lookup(ifp->if_fib, &kdst, scopeid, 0, 0);
2271 if (nh != NULL) {
2272 struct in6_addr nh_addr;
2273 nh_addr = ifatoia6(nh->nh_ifa)->ia_addr.sin6_addr;
2274 if ((nh->nh_flags & NHF_GATEWAY) == 0) {
2275 nd6log((LOG_ERR,
2276 "ICMP6 redirect rejected; no route "
2277 "with inet6 gateway found for redirect dst: %s\n",
2278 icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2279 goto bad;
2280 }
2281
2282 /*
2283 * Embed scope zone id into next hop address.
2284 */
2285 nh_addr = nh->gw6_sa.sin6_addr;
2286
2287 if (IN6_ARE_ADDR_EQUAL(&src6, &nh_addr) == 0) {
2288 nd6log((LOG_ERR,
2289 "ICMP6 redirect rejected; "
2290 "not equal to gw-for-src=%s (must be same): "
2291 "%s\n",
2292 ip6_sprintf(ip6buf, &nh_addr),
2293 icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2294 goto bad;
2295 }
2296 } else {
2297 nd6log((LOG_ERR,
2298 "ICMP6 redirect rejected; "
2299 "no route found for redirect dst: %s\n",
2300 icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2301 goto bad;
2302 }
2303 }
2304 if (IN6_IS_ADDR_MULTICAST(&reddst6)) {
2305 nd6log((LOG_ERR,
2306 "ICMP6 redirect rejected; "
2307 "redirect dst must be unicast: %s\n",
2308 icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2309 goto bad;
2310 }
2311
2312 is_router = is_onlink = 0;
2313 if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
2314 is_router = 1; /* router case */
2315 if (bcmp(&redtgt6, &reddst6, sizeof(redtgt6)) == 0)
2316 is_onlink = 1; /* on-link destination case */
2317 if (!is_router && !is_onlink) {
2318 nd6log((LOG_ERR,
2319 "ICMP6 redirect rejected; "
2320 "neither router case nor onlink case: %s\n",
2321 icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2322 goto bad;
2323 }
2324
2325 icmp6len -= sizeof(*nd_rd);
2326 nd6_option_init(nd_rd + 1, icmp6len, &ndopts);
2327 if (nd6_options(&ndopts) < 0) {
2328 nd6log((LOG_INFO, "%s: invalid ND option, rejected: %s\n",
2329 __func__, icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2330 /* nd6_options have incremented stats */
2331 goto freeit;
2332 }
2333
2334 lladdr = NULL;
2335 lladdrlen = 0;
2336 if (ndopts.nd_opts_tgt_lladdr) {
2337 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
2338 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
2339 }
2340
2341 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
2342 nd6log((LOG_INFO, "%s: lladdrlen mismatch for %s "
2343 "(if %d, icmp6 packet %d): %s\n",
2344 __func__, ip6_sprintf(ip6buf, &redtgt6),
2345 ifp->if_addrlen, lladdrlen - 2,
2346 icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2347 goto bad;
2348 }
2349
2350 /* Validation passed. */
2351
2352 /* RFC 2461 8.3 */
2353 nd6_cache_lladdr(ifp, &redtgt6, lladdr, lladdrlen, ND_REDIRECT,
2354 is_onlink ? ND_REDIRECT_ONLINK : ND_REDIRECT_ROUTER);
2355
2356 /*
2357 * Install a gateway route in the better-router case or an interface
2358 * route in the on-link-destination case.
2359 */
2360 {
2361 struct sockaddr_in6 sdst;
2362 struct sockaddr_in6 sgw;
2363 struct sockaddr_in6 ssrc;
2364 struct sockaddr *gw;
2365 int rt_flags;
2366 u_int fibnum;
2367
2368 bzero(&sdst, sizeof(sdst));
2369 bzero(&ssrc, sizeof(ssrc));
2370 sdst.sin6_family = ssrc.sin6_family = AF_INET6;
2371 sdst.sin6_len = ssrc.sin6_len = sizeof(struct sockaddr_in6);
2372 bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
2373 bcopy(&src6, &ssrc.sin6_addr, sizeof(struct in6_addr));
2374 rt_flags = 0;
2375 if (is_router) {
2376 bzero(&sgw, sizeof(sgw));
2377 sgw.sin6_family = AF_INET6;
2378 sgw.sin6_len = sizeof(struct sockaddr_in6);
2379 bcopy(&redtgt6, &sgw.sin6_addr,
2380 sizeof(struct in6_addr));
2381 gw = (struct sockaddr *)&sgw;
2382 rt_flags |= RTF_GATEWAY;
2383 } else
2384 gw = ifp->if_addr->ifa_addr;
2385 for (fibnum = 0; fibnum < rt_numfibs; fibnum++)
2386 rib_add_redirect(fibnum, (struct sockaddr *)&sdst, gw,
2387 (struct sockaddr *)&ssrc, ifp, rt_flags,
2388 V_icmp6_redirtimeout);
2389 }
2390 /* finally update cached route in each socket via pfctlinput */
2391 {
2392 struct sockaddr_in6 sdst;
2393
2394 bzero(&sdst, sizeof(sdst));
2395 sdst.sin6_family = AF_INET6;
2396 sdst.sin6_len = sizeof(struct sockaddr_in6);
2397 bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
2398 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&sdst);
2399 }
2400
2401 freeit:
2402 m_freem(m);
2403 return;
2404
2405 bad:
2406 ICMP6STAT_INC(icp6s_badredirect);
2407 m_freem(m);
2408 }
2409
2410 void
icmp6_redirect_output(struct mbuf * m0,struct nhop_object * nh)2411 icmp6_redirect_output(struct mbuf *m0, struct nhop_object *nh)
2412 {
2413 struct ifnet *ifp; /* my outgoing interface */
2414 struct in6_addr *ifp_ll6;
2415 struct in6_addr *router_ll6;
2416 struct ip6_hdr *sip6; /* m0 as struct ip6_hdr */
2417 struct mbuf *m = NULL; /* newly allocated one */
2418 struct m_tag *mtag;
2419 struct ip6_hdr *ip6; /* m as struct ip6_hdr */
2420 struct nd_redirect *nd_rd;
2421 struct llentry *ln = NULL;
2422 size_t maxlen;
2423 u_char *p;
2424 struct ifnet *outif = NULL;
2425 struct sockaddr_in6 src_sa;
2426
2427 icmp6_errcount(ND_REDIRECT, 0);
2428
2429 /* if we are not router, we don't send icmp6 redirect */
2430 if (!V_ip6_forwarding)
2431 goto fail;
2432
2433 /* sanity check */
2434 if (!m0 || !nh || !(NH_IS_VALID(nh)) || !(ifp = nh->nh_ifp))
2435 goto fail;
2436
2437 /*
2438 * Address check:
2439 * the source address must identify a neighbor, and
2440 * the destination address must not be a multicast address
2441 * [RFC 2461, sec 8.2]
2442 */
2443 sip6 = mtod(m0, struct ip6_hdr *);
2444 bzero(&src_sa, sizeof(src_sa));
2445 src_sa.sin6_family = AF_INET6;
2446 src_sa.sin6_len = sizeof(src_sa);
2447 src_sa.sin6_addr = sip6->ip6_src;
2448 if (nd6_is_addr_neighbor(&src_sa, ifp) == 0)
2449 goto fail;
2450 if (IN6_IS_ADDR_MULTICAST(&sip6->ip6_dst))
2451 goto fail; /* what should we do here? */
2452
2453 /* rate limit */
2454 if (icmp6_ratelimit(&sip6->ip6_src, ND_REDIRECT, 0))
2455 goto fail;
2456
2457 /*
2458 * Since we are going to append up to 1280 bytes (= IPV6_MMTU),
2459 * we almost always ask for an mbuf cluster for simplicity.
2460 * (MHLEN < IPV6_MMTU is almost always true)
2461 */
2462 #if IPV6_MMTU >= MCLBYTES
2463 # error assumption failed about IPV6_MMTU and MCLBYTES
2464 #endif
2465 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
2466 if (m == NULL)
2467 goto fail;
2468 M_SETFIB(m, M_GETFIB(m0));
2469 maxlen = M_TRAILINGSPACE(m);
2470 maxlen = min(IPV6_MMTU, maxlen);
2471 /* just for safety */
2472 if (maxlen < sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) +
2473 ((sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7)) {
2474 goto fail;
2475 }
2476
2477 {
2478 /* get ip6 linklocal address for ifp(my outgoing interface). */
2479 struct in6_ifaddr *ia;
2480 if ((ia = in6ifa_ifpforlinklocal(ifp,
2481 IN6_IFF_NOTREADY|
2482 IN6_IFF_ANYCAST)) == NULL)
2483 goto fail;
2484 ifp_ll6 = &ia->ia_addr.sin6_addr;
2485 /* XXXRW: reference released prematurely. */
2486 ifa_free(&ia->ia_ifa);
2487 }
2488
2489 /* get ip6 linklocal address for the router. */
2490 if (nh->nh_flags & NHF_GATEWAY) {
2491 struct sockaddr_in6 *sin6;
2492 sin6 = &nh->gw6_sa;
2493 router_ll6 = &sin6->sin6_addr;
2494 if (!IN6_IS_ADDR_LINKLOCAL(router_ll6))
2495 router_ll6 = (struct in6_addr *)NULL;
2496 } else
2497 router_ll6 = (struct in6_addr *)NULL;
2498
2499 /* ip6 */
2500 ip6 = mtod(m, struct ip6_hdr *);
2501 ip6->ip6_flow = 0;
2502 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
2503 ip6->ip6_vfc |= IPV6_VERSION;
2504 /* ip6->ip6_plen will be set later */
2505 ip6->ip6_nxt = IPPROTO_ICMPV6;
2506 ip6->ip6_hlim = 255;
2507 /* ip6->ip6_src must be linklocal addr for my outgoing if. */
2508 bcopy(ifp_ll6, &ip6->ip6_src, sizeof(struct in6_addr));
2509 bcopy(&sip6->ip6_src, &ip6->ip6_dst, sizeof(struct in6_addr));
2510
2511 /* ND Redirect */
2512 nd_rd = (struct nd_redirect *)(ip6 + 1);
2513 nd_rd->nd_rd_type = ND_REDIRECT;
2514 nd_rd->nd_rd_code = 0;
2515 nd_rd->nd_rd_reserved = 0;
2516 if (nh->nh_flags & NHF_GATEWAY) {
2517 /*
2518 * nd_rd->nd_rd_target must be a link-local address in
2519 * better router cases.
2520 */
2521 if (!router_ll6)
2522 goto fail;
2523 bcopy(router_ll6, &nd_rd->nd_rd_target,
2524 sizeof(nd_rd->nd_rd_target));
2525 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
2526 sizeof(nd_rd->nd_rd_dst));
2527 } else {
2528 /* make sure redtgt == reddst */
2529 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_target,
2530 sizeof(nd_rd->nd_rd_target));
2531 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
2532 sizeof(nd_rd->nd_rd_dst));
2533 }
2534
2535 p = (u_char *)(nd_rd + 1);
2536
2537 if (!router_ll6)
2538 goto nolladdropt;
2539
2540 {
2541 /* target lladdr option */
2542 int len;
2543 struct nd_opt_hdr *nd_opt;
2544 char *lladdr;
2545
2546 ln = nd6_lookup(router_ll6, LLE_SF(AF_INET6, 0), ifp);
2547 if (ln == NULL)
2548 goto nolladdropt;
2549
2550 len = sizeof(*nd_opt) + ifp->if_addrlen;
2551 len = (len + 7) & ~7; /* round by 8 */
2552 /* safety check */
2553 if (len + (p - (u_char *)ip6) > maxlen)
2554 goto nolladdropt;
2555
2556 if (ln->la_flags & LLE_VALID) {
2557 nd_opt = (struct nd_opt_hdr *)p;
2558 nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
2559 nd_opt->nd_opt_len = len >> 3;
2560 lladdr = (char *)(nd_opt + 1);
2561 bcopy(ln->ll_addr, lladdr, ifp->if_addrlen);
2562 p += len;
2563 }
2564 }
2565 nolladdropt:
2566 if (ln != NULL)
2567 LLE_RUNLOCK(ln);
2568
2569 m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
2570
2571 /* just to be safe */
2572 #ifdef M_DECRYPTED /*not openbsd*/
2573 if (m0->m_flags & M_DECRYPTED)
2574 goto noredhdropt;
2575 #endif
2576 if (p - (u_char *)ip6 > maxlen)
2577 goto noredhdropt;
2578
2579 {
2580 /* redirected header option */
2581 int len;
2582 struct nd_opt_rd_hdr *nd_opt_rh;
2583
2584 /*
2585 * compute the maximum size for icmp6 redirect header option.
2586 * XXX room for auth header?
2587 */
2588 len = maxlen - (p - (u_char *)ip6);
2589 len &= ~7;
2590
2591 /* This is just for simplicity. */
2592 if (m0->m_pkthdr.len != m0->m_len) {
2593 if (m0->m_next) {
2594 m_freem(m0->m_next);
2595 m0->m_next = NULL;
2596 }
2597 m0->m_pkthdr.len = m0->m_len;
2598 }
2599
2600 /*
2601 * Redirected header option spec (RFC2461 4.6.3) talks nothing
2602 * about padding/truncate rule for the original IP packet.
2603 * From the discussion on IPv6imp in Feb 1999,
2604 * the consensus was:
2605 * - "attach as much as possible" is the goal
2606 * - pad if not aligned (original size can be guessed by
2607 * original ip6 header)
2608 * Following code adds the padding if it is simple enough,
2609 * and truncates if not.
2610 */
2611 if (m0->m_next || m0->m_pkthdr.len != m0->m_len)
2612 panic("assumption failed in %s:%d", __FILE__,
2613 __LINE__);
2614
2615 if (len - sizeof(*nd_opt_rh) < m0->m_pkthdr.len) {
2616 /* not enough room, truncate */
2617 m0->m_pkthdr.len = m0->m_len = len -
2618 sizeof(*nd_opt_rh);
2619 } else {
2620 /* enough room, pad or truncate */
2621 size_t extra;
2622
2623 extra = m0->m_pkthdr.len % 8;
2624 if (extra) {
2625 /* pad if easy enough, truncate if not */
2626 if (8 - extra <= M_TRAILINGSPACE(m0)) {
2627 /* pad */
2628 m0->m_len += (8 - extra);
2629 m0->m_pkthdr.len += (8 - extra);
2630 } else {
2631 /* truncate */
2632 m0->m_pkthdr.len -= extra;
2633 m0->m_len -= extra;
2634 }
2635 }
2636 len = m0->m_pkthdr.len + sizeof(*nd_opt_rh);
2637 m0->m_pkthdr.len = m0->m_len = len -
2638 sizeof(*nd_opt_rh);
2639 }
2640
2641 nd_opt_rh = (struct nd_opt_rd_hdr *)p;
2642 bzero(nd_opt_rh, sizeof(*nd_opt_rh));
2643 nd_opt_rh->nd_opt_rh_type = ND_OPT_REDIRECTED_HEADER;
2644 nd_opt_rh->nd_opt_rh_len = len >> 3;
2645 p += sizeof(*nd_opt_rh);
2646 m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
2647
2648 /* connect m0 to m */
2649 m_tag_delete_chain(m0, NULL);
2650 m0->m_flags &= ~M_PKTHDR;
2651 m->m_next = m0;
2652 m->m_pkthdr.len = m->m_len + m0->m_len;
2653 m0 = NULL;
2654 }
2655 noredhdropt:;
2656 if (m0) {
2657 m_freem(m0);
2658 m0 = NULL;
2659 }
2660
2661 /* XXX: clear embedded link IDs in the inner header */
2662 in6_clearscope(&sip6->ip6_src);
2663 in6_clearscope(&sip6->ip6_dst);
2664 in6_clearscope(&nd_rd->nd_rd_target);
2665 in6_clearscope(&nd_rd->nd_rd_dst);
2666
2667 ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
2668
2669 nd_rd->nd_rd_cksum = 0;
2670 nd_rd->nd_rd_cksum = in6_cksum(m, IPPROTO_ICMPV6,
2671 sizeof(*ip6), ntohs(ip6->ip6_plen));
2672
2673 if (send_sendso_input_hook != NULL) {
2674 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING, sizeof(unsigned short),
2675 M_NOWAIT);
2676 if (mtag == NULL)
2677 goto fail;
2678 *(unsigned short *)(mtag + 1) = nd_rd->nd_rd_type;
2679 m_tag_prepend(m, mtag);
2680 }
2681
2682 /* send the packet to outside... */
2683 ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
2684 if (outif) {
2685 icmp6_ifstat_inc(outif, ifs6_out_msg);
2686 icmp6_ifstat_inc(outif, ifs6_out_redirect);
2687 }
2688 ICMP6STAT_INC(icp6s_outhist[ND_REDIRECT]);
2689
2690 return;
2691
2692 fail:
2693 if (m)
2694 m_freem(m);
2695 if (m0)
2696 m_freem(m0);
2697 }
2698
2699 /*
2700 * ICMPv6 socket option processing.
2701 */
2702 int
icmp6_ctloutput(struct socket * so,struct sockopt * sopt)2703 icmp6_ctloutput(struct socket *so, struct sockopt *sopt)
2704 {
2705 int error = 0;
2706 int optlen;
2707 struct inpcb *inp = sotoinpcb(so);
2708 int level, op, optname;
2709
2710 if (sopt) {
2711 level = sopt->sopt_level;
2712 op = sopt->sopt_dir;
2713 optname = sopt->sopt_name;
2714 optlen = sopt->sopt_valsize;
2715 } else
2716 level = op = optname = optlen = 0;
2717
2718 if (level != IPPROTO_ICMPV6) {
2719 return EINVAL;
2720 }
2721
2722 switch (op) {
2723 case PRCO_SETOPT:
2724 switch (optname) {
2725 case ICMP6_FILTER:
2726 {
2727 struct icmp6_filter ic6f;
2728
2729 if (optlen != sizeof(ic6f)) {
2730 error = EMSGSIZE;
2731 break;
2732 }
2733 error = sooptcopyin(sopt, &ic6f, optlen, optlen);
2734 if (error == 0) {
2735 INP_WLOCK(inp);
2736 *inp->in6p_icmp6filt = ic6f;
2737 INP_WUNLOCK(inp);
2738 }
2739 break;
2740 }
2741
2742 default:
2743 error = ENOPROTOOPT;
2744 break;
2745 }
2746 break;
2747
2748 case PRCO_GETOPT:
2749 switch (optname) {
2750 case ICMP6_FILTER:
2751 {
2752 struct icmp6_filter ic6f;
2753
2754 INP_RLOCK(inp);
2755 ic6f = *inp->in6p_icmp6filt;
2756 INP_RUNLOCK(inp);
2757 error = sooptcopyout(sopt, &ic6f, sizeof(ic6f));
2758 break;
2759 }
2760
2761 default:
2762 error = ENOPROTOOPT;
2763 break;
2764 }
2765 break;
2766 }
2767
2768 return (error);
2769 }
2770
2771 SYSCTL_DECL(_net_inet6_icmp6);
2772
2773 static int sysctl_icmp6lim_and_jitter(SYSCTL_HANDLER_ARGS);
2774 VNET_DEFINE_STATIC(u_int, icmp6errppslim) = 100;
2775 #define V_icmp6errppslim VNET(icmp6errppslim)
2776 SYSCTL_PROC(_net_inet6_icmp6, ICMPV6CTL_ERRPPSLIMIT, errppslimit,
2777 CTLTYPE_UINT | CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6errppslim), 0,
2778 &sysctl_icmp6lim_and_jitter, "IU",
2779 "Maximum number of ICMPv6 error/reply messages per second");
2780
2781 typedef enum {
2782 RATELIM_PARAM_PROB = 0,
2783 RATELIM_TOO_BIG,
2784 RATELIM_UNREACH,
2785 RATELIM_TEXCEED,
2786 RATELIM_REDIR,
2787 RATELIM_REPLY,
2788 RATELIM_OTHER,
2789 RATELIM_MAX
2790 } ratelim_which;
2791
2792 static const char *icmp6_rate_descrs[RATELIM_MAX] = {
2793 [RATELIM_PARAM_PROB] = "bad IPv6 header",
2794 [RATELIM_TOO_BIG] = "packet too big",
2795 [RATELIM_UNREACH] = "destination unreachable",
2796 [RATELIM_TEXCEED] = "time exceeded",
2797 [RATELIM_REPLY] = "echo reply",
2798 [RATELIM_REDIR] = "neighbor discovery redirect",
2799 [RATELIM_OTHER] = "(other)",
2800 };
2801
2802 VNET_DEFINE_STATIC(int, icmp6lim_curr_jitter[RATELIM_MAX]) = {0};
2803 #define V_icmp6lim_curr_jitter VNET(icmp6lim_curr_jitter)
2804
2805 VNET_DEFINE_STATIC(u_int, icmp6lim_jitter) = 8;
2806 #define V_icmp6lim_jitter VNET(icmp6lim_jitter)
2807 SYSCTL_PROC(_net_inet6_icmp6, OID_AUTO, icmp6lim_jitter, CTLTYPE_UINT |
2808 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6lim_jitter), 0,
2809 &sysctl_icmp6lim_and_jitter, "IU",
2810 "Random errppslimit jitter adjustment limit");
2811
2812 VNET_DEFINE_STATIC(int, icmp6lim_output) = 1;
2813 #define V_icmp6lim_output VNET(icmp6lim_output)
2814 SYSCTL_INT(_net_inet6_icmp6, OID_AUTO, icmp6lim_output,
2815 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6lim_output), 0,
2816 "Enable logging of ICMPv6 response rate limiting");
2817
2818 static void
icmp6lim_new_jitter(int which)2819 icmp6lim_new_jitter(int which)
2820 {
2821 /*
2822 * Adjust limit +/- to jitter the measurement to deny a side-channel
2823 * port scan as in https://dl.acm.org/doi/10.1145/3372297.3417280
2824 */
2825 KASSERT(which >= 0 && which < RATELIM_MAX,
2826 ("%s: which %d", __func__, which));
2827 if (V_icmp6lim_jitter > 0)
2828 V_icmp6lim_curr_jitter[which] =
2829 arc4random_uniform(V_icmp6lim_jitter * 2 + 1) -
2830 V_icmp6lim_jitter;
2831 }
2832
2833 static int
sysctl_icmp6lim_and_jitter(SYSCTL_HANDLER_ARGS)2834 sysctl_icmp6lim_and_jitter(SYSCTL_HANDLER_ARGS)
2835 {
2836 uint32_t new;
2837 int error;
2838 bool lim;
2839
2840 MPASS(oidp->oid_arg1 == &VNET_NAME(icmp6errppslim) ||
2841 oidp->oid_arg1 == &VNET_NAME(icmp6lim_jitter));
2842
2843 lim = (oidp->oid_arg1 == &VNET_NAME(icmp6errppslim));
2844 new = lim ? V_icmp6errppslim : V_icmp6lim_jitter;
2845 error = sysctl_handle_int(oidp, &new, 0, req);
2846 if (error == 0 && req->newptr) {
2847 if (lim) {
2848 if (new != 0 && new <= V_icmp6lim_jitter)
2849 error = EINVAL;
2850 else
2851 V_icmp6errppslim = new;
2852 } else {
2853 if (new >= V_icmp6errppslim)
2854 error = EINVAL;
2855 else {
2856 V_icmp6lim_jitter = new;
2857 for (int i = 0; i < RATELIM_MAX; i++) {
2858 icmp6lim_new_jitter(i);
2859 }
2860 }
2861 }
2862 }
2863 MPASS(V_icmp6errppslim == 0 || V_icmp6errppslim > V_icmp6lim_jitter);
2864
2865 return (error);
2866 }
2867
2868
2869 VNET_DEFINE_STATIC(struct counter_rate, icmp6_rates[RATELIM_MAX]);
2870 #define V_icmp6_rates VNET(icmp6_rates)
2871
2872 static void
icmp6_ratelimit_init(void)2873 icmp6_ratelimit_init(void)
2874 {
2875
2876 for (int i = 0; i < RATELIM_MAX; i++) {
2877 V_icmp6_rates[i].cr_rate = counter_u64_alloc(M_WAITOK);
2878 V_icmp6_rates[i].cr_ticks = ticks;
2879 icmp6lim_new_jitter(i);
2880 }
2881 }
2882 VNET_SYSINIT(icmp6_ratelimit, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY,
2883 icmp6_ratelimit_init, NULL);
2884
2885 #ifdef VIMAGE
2886 static void
icmp6_ratelimit_uninit(void)2887 icmp6_ratelimit_uninit(void)
2888 {
2889
2890 for (int i = 0; i < RATELIM_MAX; i++)
2891 counter_u64_free(V_icmp6_rates[i].cr_rate);
2892 }
2893 VNET_SYSUNINIT(icmp6_ratelimit, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD,
2894 icmp6_ratelimit_uninit, NULL);
2895 #endif
2896
2897 /*
2898 * Perform rate limit check.
2899 * Returns 0 if it is okay to send the icmp6 packet.
2900 * Returns 1 if the router SHOULD NOT send this icmp6 packet due to rate
2901 * limitation.
2902 *
2903 * XXX per-destination/type check necessary?
2904 *
2905 * dst - not used at this moment
2906 * code - not used at this moment
2907 */
2908 static int
icmp6_ratelimit(const struct in6_addr * dst,const int type,const int code)2909 icmp6_ratelimit(const struct in6_addr *dst, const int type, const int code)
2910 {
2911 ratelim_which which;
2912 int64_t pps;
2913
2914 if (V_icmp6errppslim == 0)
2915 return (0);
2916
2917 switch (type) {
2918 case ICMP6_PARAM_PROB:
2919 which = RATELIM_PARAM_PROB;
2920 break;
2921 case ICMP6_PACKET_TOO_BIG:
2922 which = RATELIM_TOO_BIG;
2923 break;
2924 case ICMP6_DST_UNREACH:
2925 which = RATELIM_UNREACH;
2926 break;
2927 case ICMP6_TIME_EXCEEDED:
2928 which = RATELIM_TEXCEED;
2929 break;
2930 case ND_REDIRECT:
2931 which = RATELIM_REDIR;
2932 break;
2933 case ICMP6_ECHO_REPLY:
2934 which = RATELIM_REPLY;
2935 break;
2936 default:
2937 which = RATELIM_OTHER;
2938 break;
2939 };
2940
2941 pps = counter_ratecheck(&V_icmp6_rates[which], V_icmp6errppslim +
2942 V_icmp6lim_curr_jitter[which]);
2943 if (pps > 0) {
2944 if (V_icmp6lim_output)
2945 log(LOG_NOTICE, "Limiting ICMPv6 %s output from %jd "
2946 "to %d packets/sec\n", icmp6_rate_descrs[which],
2947 (intmax_t )pps, V_icmp6errppslim +
2948 V_icmp6lim_curr_jitter[which]);
2949 icmp6lim_new_jitter(which);
2950 }
2951 if (pps == -1) {
2952 ICMP6STAT_INC(icp6s_toofreq);
2953 return (-1);
2954 }
2955
2956 return (0);
2957 }
2958