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
63 #include <sys/cdefs.h>
64 #define MBUF_PRIVATE /* XXXRW: Optimisation tries to avoid M_EXT mbufs */
65
66 #include "opt_inet.h"
67 #include "opt_inet6.h"
68
69 #include <sys/param.h>
70 #include <sys/domain.h>
71 #include <sys/jail.h>
72 #include <sys/kernel.h>
73 #include <sys/lock.h>
74 #include <sys/malloc.h>
75 #include <sys/mbuf.h>
76 #include <sys/proc.h>
77 #include <sys/protosw.h>
78 #include <sys/signalvar.h>
79 #include <sys/socket.h>
80 #include <sys/socketvar.h>
81 #include <sys/sx.h>
82 #include <sys/syslog.h>
83 #include <sys/systm.h>
84 #include <sys/time.h>
85
86 #include <net/if.h>
87 #include <net/if_var.h>
88 #include <net/if_dl.h>
89 #include <net/if_llatbl.h>
90 #include <net/if_private.h>
91 #include <net/if_types.h>
92 #include <net/route.h>
93 #include <net/route/route_ctl.h>
94 #include <net/route/nhop.h>
95 #include <net/vnet.h>
96
97 #include <netinet/in.h>
98 #include <netinet/in_pcb.h>
99 #include <netinet/in_var.h>
100 #include <netinet/ip6.h>
101 #include <netinet/icmp6.h>
102 #include <netinet/tcp_var.h>
103
104 #include <netinet6/in6_fib.h>
105 #include <netinet6/in6_ifattach.h>
106 #include <netinet6/in6_pcb.h>
107 #include <netinet6/ip6_var.h>
108 #include <netinet6/scope6_var.h>
109 #include <netinet6/mld6_var.h>
110 #include <netinet6/nd6.h>
111 #include <netinet6/send.h>
112
113 extern ip6proto_ctlinput_t *ip6_ctlprotox[];
114
115 VNET_PCPUSTAT_DEFINE(struct icmp6stat, icmp6stat);
116 VNET_PCPUSTAT_SYSINIT(icmp6stat);
117 SYSCTL_VNET_PCPUSTAT(_net_inet6_icmp6, ICMPV6CTL_STATS, stats,
118 struct icmp6stat, icmp6stat,
119 "ICMPv6 statistics (struct icmp6stat, netinet/icmp6.h)");
120
121 #ifdef VIMAGE
122 VNET_PCPUSTAT_SYSUNINIT(icmp6stat);
123 #endif /* VIMAGE */
124
125 VNET_DEFINE_STATIC(int, icmp6_rediraccept) = 1;
126 #define V_icmp6_rediraccept VNET(icmp6_rediraccept)
127 SYSCTL_INT(_net_inet6_icmp6, ICMPV6CTL_REDIRACCEPT, rediraccept,
128 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6_rediraccept), 0,
129 "Accept ICMPv6 redirect messages");
130
131 VNET_DEFINE_STATIC(int, icmp6_redirtimeout) = 10 * 60; /* 10 minutes */
132 #define V_icmp6_redirtimeout VNET(icmp6_redirtimeout)
133 SYSCTL_INT(_net_inet6_icmp6, ICMPV6CTL_REDIRTIMEOUT, redirtimeout,
134 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6_redirtimeout), 0,
135 "Delay in seconds before expiring redirect route");
136
137 VNET_DEFINE_STATIC(int, icmp6_nodeinfo) = 0;
138 #define V_icmp6_nodeinfo VNET(icmp6_nodeinfo)
139 SYSCTL_INT(_net_inet6_icmp6, ICMPV6CTL_NODEINFO, nodeinfo,
140 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6_nodeinfo), 0,
141 "Mask of enabled RFC4620 node information query types");
142
143 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
144 #define V_ripcbinfo VNET(ripcbinfo)
145
146 VNET_DECLARE(int, rip_bind_all_fibs);
147 #define V_rip_bind_all_fibs VNET(rip_bind_all_fibs)
148
149 static void icmp6_errcount(int, int);
150 static int icmp6_rip6_input(struct mbuf **, int);
151 static void icmp6_reflect(struct mbuf *, size_t);
152 static const char *icmp6_redirect_diag(struct in6_addr *,
153 struct in6_addr *, struct in6_addr *);
154 static struct mbuf *ni6_input(struct mbuf *, int, struct prison *);
155 static struct mbuf *ni6_nametodns(const char *, int, int);
156 static int ni6_dnsmatch(const char *, int, const char *, int);
157 static int ni6_addrs(struct icmp6_nodeinfo *, struct mbuf *,
158 struct ifnet **, struct in6_addr *);
159 static int ni6_store_addrs(struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
160 struct ifnet *, int);
161 static int icmp6_notify_error(struct mbuf **, int, int);
162
163 /*
164 * Kernel module interface for updating icmp6stat. The argument is an index
165 * into icmp6stat treated as an array of u_quad_t. While this encodes the
166 * general layout of icmp6stat into the caller, it doesn't encode its
167 * location, so that future changes to add, for example, per-CPU stats
168 * support won't cause binary compatibility problems for kernel modules.
169 */
170 void
kmod_icmp6stat_inc(int statnum)171 kmod_icmp6stat_inc(int statnum)
172 {
173
174 counter_u64_add(VNET(icmp6stat)[statnum], 1);
175 }
176
177 static void
icmp6_errcount(int type,int code)178 icmp6_errcount(int type, int code)
179 {
180 switch (type) {
181 case ICMP6_DST_UNREACH:
182 switch (code) {
183 case ICMP6_DST_UNREACH_NOROUTE:
184 ICMP6STAT_INC(icp6s_odst_unreach_noroute);
185 return;
186 case ICMP6_DST_UNREACH_ADMIN:
187 ICMP6STAT_INC(icp6s_odst_unreach_admin);
188 return;
189 case ICMP6_DST_UNREACH_BEYONDSCOPE:
190 ICMP6STAT_INC(icp6s_odst_unreach_beyondscope);
191 return;
192 case ICMP6_DST_UNREACH_ADDR:
193 ICMP6STAT_INC(icp6s_odst_unreach_addr);
194 return;
195 case ICMP6_DST_UNREACH_NOPORT:
196 ICMP6STAT_INC(icp6s_odst_unreach_noport);
197 return;
198 }
199 break;
200 case ICMP6_PACKET_TOO_BIG:
201 ICMP6STAT_INC(icp6s_opacket_too_big);
202 return;
203 case ICMP6_TIME_EXCEEDED:
204 switch (code) {
205 case ICMP6_TIME_EXCEED_TRANSIT:
206 ICMP6STAT_INC(icp6s_otime_exceed_transit);
207 return;
208 case ICMP6_TIME_EXCEED_REASSEMBLY:
209 ICMP6STAT_INC(icp6s_otime_exceed_reassembly);
210 return;
211 }
212 break;
213 case ICMP6_PARAM_PROB:
214 switch (code) {
215 case ICMP6_PARAMPROB_HEADER:
216 ICMP6STAT_INC(icp6s_oparamprob_header);
217 return;
218 case ICMP6_PARAMPROB_NEXTHEADER:
219 ICMP6STAT_INC(icp6s_oparamprob_nextheader);
220 return;
221 case ICMP6_PARAMPROB_OPTION:
222 ICMP6STAT_INC(icp6s_oparamprob_option);
223 return;
224 }
225 break;
226 case ND_REDIRECT:
227 ICMP6STAT_INC(icp6s_oredirect);
228 return;
229 }
230 ICMP6STAT_INC(icp6s_ounknown);
231 }
232
233 /*
234 * A wrapper function for icmp6_error() necessary when the erroneous packet
235 * may not contain enough scope zone information.
236 */
237 void
icmp6_error2(struct mbuf * m,int type,int code,int param,struct ifnet * ifp)238 icmp6_error2(struct mbuf *m, int type, int code, int param,
239 struct ifnet *ifp)
240 {
241 struct ip6_hdr *ip6;
242
243 if (ifp == NULL)
244 return;
245
246 if (m->m_len < sizeof(struct ip6_hdr)) {
247 m = m_pullup(m, sizeof(struct ip6_hdr));
248 if (m == NULL) {
249 IP6STAT_INC(ip6s_exthdrtoolong);
250 return;
251 }
252 }
253 ip6 = mtod(m, struct ip6_hdr *);
254
255 if (in6_setscope(&ip6->ip6_src, ifp, NULL) != 0)
256 return;
257 if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
258 return;
259
260 icmp6_error(m, type, code, param);
261 }
262
263 /*
264 * Generate an error packet of type error in response to bad IP6 packet.
265 */
266 void
icmp6_error(struct mbuf * m,int type,int code,int param)267 icmp6_error(struct mbuf *m, int type, int code, int param)
268 {
269 struct ip6_hdr *oip6, *nip6;
270 struct icmp6_hdr *icmp6;
271 struct epoch_tracker et;
272 u_int preplen;
273 int off;
274 int nxt;
275
276 ICMP6STAT_INC(icp6s_error);
277
278 /* count per-type-code statistics */
279 icmp6_errcount(type, code);
280
281 #ifdef M_DECRYPTED /*not openbsd*/
282 if (m->m_flags & M_DECRYPTED) {
283 ICMP6STAT_INC(icp6s_canterror);
284 goto freeit;
285 }
286 #endif
287
288 if (m->m_len < sizeof(struct ip6_hdr)) {
289 m = m_pullup(m, sizeof(struct ip6_hdr));
290 if (m == NULL) {
291 IP6STAT_INC(ip6s_exthdrtoolong);
292 return;
293 }
294 }
295 oip6 = mtod(m, struct ip6_hdr *);
296
297 /*
298 * If the destination address of the erroneous packet is a multicast
299 * address, or the packet was sent using link-layer multicast,
300 * we should basically suppress sending an error (RFC 2463, Section
301 * 2.4).
302 * We have two exceptions (the item e.2 in that section):
303 * - the Packet Too Big message can be sent for path MTU discovery.
304 * - the Parameter Problem Message that can be allowed an icmp6 error
305 * in the option type field. This check has been done in
306 * ip6_unknown_opt(), so we can just check the type and code.
307 */
308 if ((m->m_flags & (M_BCAST|M_MCAST) ||
309 IN6_IS_ADDR_MULTICAST(&oip6->ip6_dst)) &&
310 (type != ICMP6_PACKET_TOO_BIG &&
311 (type != ICMP6_PARAM_PROB ||
312 code != ICMP6_PARAMPROB_OPTION)))
313 goto freeit;
314
315 /*
316 * RFC 2463, 2.4 (e.5): source address check.
317 * XXX: the case of anycast source?
318 */
319 if (IN6_IS_ADDR_UNSPECIFIED(&oip6->ip6_src) ||
320 IN6_IS_ADDR_MULTICAST(&oip6->ip6_src))
321 goto freeit;
322
323 /*
324 * If we are about to send ICMPv6 against ICMPv6 error/redirect,
325 * don't do it.
326 */
327 nxt = -1;
328 off = ip6_lasthdr(m, 0, IPPROTO_IPV6, &nxt);
329 if (off >= 0 && nxt == IPPROTO_ICMPV6) {
330 struct icmp6_hdr *icp;
331
332 if (m->m_len < off + sizeof(struct icmp6_hdr)) {
333 m = m_pullup(m, off + sizeof(struct icmp6_hdr));
334 if (m == NULL) {
335 IP6STAT_INC(ip6s_exthdrtoolong);
336 return;
337 }
338 }
339 oip6 = mtod(m, struct ip6_hdr *);
340 icp = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
341
342 if (icp->icmp6_type < ICMP6_ECHO_REQUEST ||
343 icp->icmp6_type == ND_REDIRECT) {
344 /*
345 * ICMPv6 error
346 * Special case: for redirect (which is
347 * informational) we must not send icmp6 error.
348 */
349 ICMP6STAT_INC(icp6s_canterror);
350 goto freeit;
351 } else {
352 /* ICMPv6 informational - send the error */
353 }
354 } else {
355 /* non-ICMPv6 - send the error */
356 }
357
358 /* Finally, do rate limitation check. */
359 if (icmp6_ratelimit(&oip6->ip6_src, type, code))
360 goto freeit;
361
362 /*
363 * OK, ICMP6 can be generated.
364 */
365
366 if (m->m_pkthdr.len >= ICMPV6_PLD_MAXLEN)
367 m_adj(m, ICMPV6_PLD_MAXLEN - m->m_pkthdr.len);
368
369 preplen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
370 M_PREPEND(m, preplen, M_NOWAIT); /* FIB is also copied over. */
371 if (m == NULL) {
372 nd6log((LOG_DEBUG, "ENOBUFS in icmp6_error %d\n", __LINE__));
373 return;
374 }
375
376 nip6 = mtod(m, struct ip6_hdr *);
377 nip6->ip6_src = oip6->ip6_src;
378 nip6->ip6_dst = oip6->ip6_dst;
379
380 in6_clearscope(&oip6->ip6_src);
381 in6_clearscope(&oip6->ip6_dst);
382
383 icmp6 = (struct icmp6_hdr *)(nip6 + 1);
384 icmp6->icmp6_type = type;
385 icmp6->icmp6_code = code;
386 icmp6->icmp6_pptr = htonl((u_int32_t)param);
387
388 ICMP6STAT_INC2(icp6s_outhist, type);
389 NET_EPOCH_ENTER(et);
390 icmp6_reflect(m, sizeof(struct ip6_hdr)); /* header order: IPv6 - ICMPv6 */
391 NET_EPOCH_EXIT(et);
392
393 return;
394
395 freeit:
396 /*
397 * If we can't tell whether or not we can generate ICMP6, free it.
398 */
399 m_freem(m);
400 }
401
402 int
icmp6_errmap(const struct icmp6_hdr * icmp6)403 icmp6_errmap(const struct icmp6_hdr *icmp6)
404 {
405
406 switch (icmp6->icmp6_type) {
407 case ICMP6_DST_UNREACH:
408 switch (icmp6->icmp6_code) {
409 case ICMP6_DST_UNREACH_NOROUTE:
410 case ICMP6_DST_UNREACH_ADDR:
411 return (EHOSTUNREACH);
412 case ICMP6_DST_UNREACH_NOPORT:
413 case ICMP6_DST_UNREACH_ADMIN:
414 return (ECONNREFUSED);
415 case ICMP6_DST_UNREACH_BEYONDSCOPE:
416 return (ENOPROTOOPT);
417 default:
418 return (0); /* Shouldn't happen. */
419 }
420 case ICMP6_PACKET_TOO_BIG:
421 return (EMSGSIZE);
422 case ICMP6_TIME_EXCEEDED:
423 switch (icmp6->icmp6_code) {
424 case ICMP6_TIME_EXCEED_TRANSIT:
425 return (EHOSTUNREACH);
426 case ICMP6_TIME_EXCEED_REASSEMBLY:
427 return (0);
428 default:
429 return (0); /* Shouldn't happen. */
430 }
431 case ICMP6_PARAM_PROB:
432 switch (icmp6->icmp6_code) {
433 case ICMP6_PARAMPROB_NEXTHEADER:
434 return (ECONNREFUSED);
435 case ICMP6_PARAMPROB_HEADER:
436 case ICMP6_PARAMPROB_OPTION:
437 return (ENOPROTOOPT);
438 default:
439 return (0); /* Shouldn't happen. */
440 }
441 default:
442 return (0);
443 }
444 }
445
446 /*
447 * Process a received ICMP6 message.
448 */
449 int
icmp6_input(struct mbuf ** mp,int * offp,int proto)450 icmp6_input(struct mbuf **mp, int *offp, int proto)
451 {
452 struct mbuf *m, *n;
453 struct ifnet *ifp;
454 struct ip6_hdr *ip6, *nip6;
455 struct icmp6_hdr *icmp6, *nicmp6;
456 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
457 int code, error, icmp6len, ip6len, noff, off, sum;
458
459 NET_EPOCH_ASSERT();
460
461 m = *mp;
462 off = *offp;
463
464 if (m->m_len < off + sizeof(struct icmp6_hdr)) {
465 m = m_pullup(m, off + sizeof(struct icmp6_hdr));
466 if (m == NULL) {
467 IP6STAT_INC(ip6s_exthdrtoolong);
468 *mp = m;
469 return (IPPROTO_DONE);
470 }
471 }
472
473 /*
474 * Locate icmp6 structure in mbuf, and check
475 * that not corrupted and of at least minimum length
476 */
477
478 icmp6len = m->m_pkthdr.len - off;
479 if (icmp6len < sizeof(struct icmp6_hdr)) {
480 ICMP6STAT_INC(icp6s_tooshort);
481 goto freeit;
482 }
483
484 ip6 = mtod(m, struct ip6_hdr *);
485 ifp = m->m_pkthdr.rcvif;
486 /*
487 * Check multicast group membership.
488 * Note: SSM filters are not applied for ICMPv6 traffic.
489 */
490 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
491 struct in6_multi *inm;
492
493 inm = in6m_lookup(ifp, &ip6->ip6_dst);
494 if (inm == NULL) {
495 IP6STAT_INC(ip6s_notmember);
496 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
497 goto freeit;
498 }
499 }
500
501 /* Calculate the checksum. */
502 icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
503 code = icmp6->icmp6_code;
504 if ((sum = in6_cksum(m, IPPROTO_ICMPV6, off, icmp6len)) != 0) {
505 nd6log((LOG_ERR,
506 "ICMP6 checksum error(%d|%x) %s\n",
507 icmp6->icmp6_type, sum,
508 ip6_sprintf(ip6bufs, &ip6->ip6_src)));
509 ICMP6STAT_INC(icp6s_checksum);
510 goto freeit;
511 }
512
513 ICMP6STAT_INC2(icp6s_inhist, icmp6->icmp6_type);
514 icmp6_ifstat_inc(ifp, ifs6_in_msg);
515 if (icmp6->icmp6_type < ICMP6_INFOMSG_MASK)
516 icmp6_ifstat_inc(ifp, ifs6_in_error);
517
518 ip6len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
519 switch (icmp6->icmp6_type) {
520 case ICMP6_DST_UNREACH:
521 icmp6_ifstat_inc(ifp, ifs6_in_dstunreach);
522 switch (code) {
523 case ICMP6_DST_UNREACH_ADMIN:
524 icmp6_ifstat_inc(ifp, ifs6_in_adminprohib);
525 case ICMP6_DST_UNREACH_NOROUTE:
526 case ICMP6_DST_UNREACH_ADDR:
527 case ICMP6_DST_UNREACH_BEYONDSCOPE:
528 case ICMP6_DST_UNREACH_NOPORT:
529 goto deliver;
530 default:
531 goto badcode;
532 }
533 case ICMP6_PACKET_TOO_BIG:
534 icmp6_ifstat_inc(ifp, ifs6_in_pkttoobig);
535 /*
536 * Validation is made in icmp6_mtudisc_update.
537 * Updating the path MTU will be done after examining
538 * intermediate extension headers.
539 */
540 goto deliver;
541 case ICMP6_TIME_EXCEEDED:
542 icmp6_ifstat_inc(ifp, ifs6_in_timeexceed);
543 switch (code) {
544 case ICMP6_TIME_EXCEED_TRANSIT:
545 case ICMP6_TIME_EXCEED_REASSEMBLY:
546 goto deliver;
547 default:
548 goto badcode;
549 }
550 case ICMP6_PARAM_PROB:
551 icmp6_ifstat_inc(ifp, ifs6_in_paramprob);
552 switch (code) {
553 case ICMP6_PARAMPROB_NEXTHEADER:
554 case ICMP6_PARAMPROB_HEADER:
555 case ICMP6_PARAMPROB_OPTION:
556 goto deliver;
557 default:
558 goto badcode;
559 }
560 case ICMP6_ECHO_REQUEST:
561 icmp6_ifstat_inc(ifp, ifs6_in_echo);
562 if (code != 0)
563 goto badcode;
564 if (icmp6_ratelimit(&ip6->ip6_src, ICMP6_ECHO_REPLY, 0))
565 break;
566 if ((n = m_copym(m, 0, M_COPYALL, M_NOWAIT)) == NULL) {
567 /* Give up remote */
568 break;
569 }
570 if (!M_WRITABLE(n)
571 || n->m_len < off + sizeof(struct icmp6_hdr)) {
572 struct mbuf *n0 = n;
573 int n0len;
574
575 CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) <= MHLEN);
576 n = m_gethdr(M_NOWAIT, n0->m_type);
577 if (n == NULL) {
578 /* Give up remote */
579 m_freem(n0);
580 break;
581 }
582
583 m_move_pkthdr(n, n0); /* FIB copied. */
584 n0len = n0->m_pkthdr.len; /* save for use below */
585 /*
586 * Copy IPv6 and ICMPv6 only.
587 */
588 nip6 = mtod(n, struct ip6_hdr *);
589 bcopy(ip6, nip6, sizeof(struct ip6_hdr));
590 nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
591 bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
592 noff = sizeof(struct ip6_hdr);
593 /* new mbuf contains only ipv6+icmpv6 headers */
594 n->m_len = noff + sizeof(struct icmp6_hdr);
595 /*
596 * Adjust mbuf. ip6_plen will be adjusted in
597 * ip6_output().
598 */
599 m_adj(n0, off + sizeof(struct icmp6_hdr));
600 /* recalculate complete packet size */
601 n->m_pkthdr.len = n0len + (noff - off);
602 n->m_next = n0;
603 } else {
604 if (n->m_len < off + sizeof(*nicmp6)) {
605 n = m_pullup(n, off + sizeof(*nicmp6));
606 if (n == NULL) {
607 IP6STAT_INC(ip6s_exthdrtoolong);
608 break;
609 }
610 }
611 nicmp6 = (struct icmp6_hdr *)(mtod(n, caddr_t) + off);
612 noff = off;
613 }
614 if (n) {
615 nicmp6->icmp6_type = ICMP6_ECHO_REPLY;
616 nicmp6->icmp6_code = 0;
617 ICMP6STAT_INC(icp6s_reflect);
618 ICMP6STAT_INC2(icp6s_outhist, ICMP6_ECHO_REPLY);
619 icmp6_reflect(n, noff);
620 }
621 break;
622
623 case ICMP6_ECHO_REPLY:
624 icmp6_ifstat_inc(ifp, ifs6_in_echoreply);
625 if (code != 0)
626 goto badcode;
627 break;
628
629 case MLD_LISTENER_QUERY:
630 case MLD_LISTENER_REPORT:
631 case MLD_LISTENER_DONE:
632 case MLDV2_LISTENER_REPORT:
633 /*
634 * Drop MLD traffic which is not link-local, has a hop limit
635 * of greater than 1 hop, or which does not have the
636 * IPv6 HBH Router Alert option.
637 * As IPv6 HBH options are stripped in ip6_input() we must
638 * check an mbuf header flag.
639 * XXX Should we also sanity check that these messages
640 * were directed to a link-local multicast prefix?
641 */
642 if ((ip6->ip6_hlim != 1) || (m->m_flags & M_RTALERT_MLD) == 0)
643 goto freeit;
644 if (mld_input(&m, off, icmp6len) != 0) {
645 *mp = NULL;
646 return (IPPROTO_DONE);
647 }
648 /* m stays. */
649 break;
650
651 case ICMP6_WRUREQUEST: /* ICMP6_FQDN_QUERY */
652 {
653 enum { WRU, FQDN } mode;
654 struct prison *pr;
655
656 if (!V_icmp6_nodeinfo)
657 break;
658
659 if (icmp6len == sizeof(struct icmp6_hdr) + 4)
660 mode = WRU;
661 else if (icmp6len >= sizeof(struct icmp6_nodeinfo))
662 mode = FQDN;
663 else
664 goto badlen;
665
666 pr = NULL;
667 sx_slock(&allprison_lock);
668 TAILQ_FOREACH(pr, &allprison, pr_list)
669 if (pr->pr_vnet == ifp->if_vnet)
670 break;
671 sx_sunlock(&allprison_lock);
672 if (pr == NULL)
673 pr = curthread->td_ucred->cr_prison;
674 if (mode == FQDN) {
675 if (m->m_len < off + sizeof(struct icmp6_nodeinfo)) {
676 m = m_pullup(m, off +
677 sizeof(struct icmp6_nodeinfo));
678 if (m == NULL) {
679 IP6STAT_INC(ip6s_exthdrtoolong);
680 *mp = m;
681 return (IPPROTO_DONE);
682 }
683 }
684 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
685 if (n)
686 n = ni6_input(n, off, pr);
687 /* XXX meaningless if n == NULL */
688 noff = sizeof(struct ip6_hdr);
689 } else {
690 u_char *p;
691 int maxhlen, hlen;
692
693 /*
694 * XXX: this combination of flags is pointless,
695 * but should we keep this for compatibility?
696 */
697 if ((V_icmp6_nodeinfo & (ICMP6_NODEINFO_FQDNOK |
698 ICMP6_NODEINFO_TMPADDROK)) !=
699 (ICMP6_NODEINFO_FQDNOK | ICMP6_NODEINFO_TMPADDROK))
700 break;
701
702 if (code != 0)
703 goto badcode;
704
705 CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) + 4 <= MHLEN);
706 n = m_gethdr(M_NOWAIT, m->m_type);
707 if (n == NULL) {
708 /* Give up remote */
709 break;
710 }
711 if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
712 /*
713 * Previous code did a blind M_COPY_PKTHDR
714 * and said "just for rcvif". If true, then
715 * we could tolerate the dup failing (due to
716 * the deep copy of the tag chain). For now
717 * be conservative and just fail.
718 */
719 m_free(n);
720 n = NULL;
721 break;
722 }
723 /*
724 * Copy IPv6 and ICMPv6 only.
725 */
726 nip6 = mtod(n, struct ip6_hdr *);
727 bcopy(ip6, nip6, sizeof(struct ip6_hdr));
728 nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
729 bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
730 p = (u_char *)(nicmp6 + 1);
731 bzero(p, 4);
732
733 maxhlen = M_TRAILINGSPACE(n) -
734 (sizeof(*nip6) + sizeof(*nicmp6) + 4);
735 mtx_lock(&pr->pr_mtx);
736 hlen = strlen(pr->pr_hostname);
737 if (maxhlen > hlen)
738 maxhlen = hlen;
739 /* meaningless TTL */
740 bcopy(pr->pr_hostname, p + 4, maxhlen);
741 mtx_unlock(&pr->pr_mtx);
742 noff = sizeof(struct ip6_hdr);
743 n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
744 sizeof(struct icmp6_hdr) + 4 + maxhlen;
745 nicmp6->icmp6_type = ICMP6_WRUREPLY;
746 nicmp6->icmp6_code = 0;
747 }
748 if (n) {
749 ICMP6STAT_INC(icp6s_reflect);
750 ICMP6STAT_INC2(icp6s_outhist, ICMP6_WRUREPLY);
751 icmp6_reflect(n, noff);
752 }
753 break;
754 }
755
756 case ICMP6_WRUREPLY:
757 if (code != 0)
758 goto badcode;
759 break;
760
761 case ND_ROUTER_SOLICIT:
762 icmp6_ifstat_inc(ifp, ifs6_in_routersolicit);
763 if (code != 0)
764 goto badcode;
765 if (icmp6len < sizeof(struct nd_router_solicit))
766 goto badlen;
767 if (send_sendso_input_hook != NULL) {
768 if (m->m_len < off + icmp6len) {
769 m = m_pullup(m, off + icmp6len);
770 if (m == NULL) {
771 IP6STAT_INC(ip6s_exthdrtoolong);
772 *mp = NULL;
773 return (IPPROTO_DONE);
774 }
775 }
776 error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
777 if (error == 0) {
778 m = NULL;
779 goto freeit;
780 }
781 }
782 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
783 nd6_rs_input(m, off, icmp6len);
784 m = n;
785 if (m == NULL)
786 goto freeit;
787 break;
788
789 case ND_ROUTER_ADVERT:
790 icmp6_ifstat_inc(ifp, ifs6_in_routeradvert);
791 if (code != 0)
792 goto badcode;
793 if (icmp6len < sizeof(struct nd_router_advert))
794 goto badlen;
795 if (send_sendso_input_hook != NULL) {
796 error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
797 if (error == 0) {
798 m = NULL;
799 goto freeit;
800 }
801 }
802 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
803 nd6_ra_input(m, off, icmp6len);
804 m = n;
805 if (m == NULL)
806 goto freeit;
807 break;
808
809 case ND_NEIGHBOR_SOLICIT:
810 icmp6_ifstat_inc(ifp, ifs6_in_neighborsolicit);
811 if (code != 0)
812 goto badcode;
813 if (icmp6len < sizeof(struct nd_neighbor_solicit))
814 goto badlen;
815 if (send_sendso_input_hook != NULL) {
816 error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
817 if (error == 0) {
818 m = NULL;
819 goto freeit;
820 }
821 }
822 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
823 nd6_ns_input(m, off, icmp6len);
824 m = n;
825 if (m == NULL)
826 goto freeit;
827 break;
828
829 case ND_NEIGHBOR_ADVERT:
830 icmp6_ifstat_inc(ifp, ifs6_in_neighboradvert);
831 if (code != 0)
832 goto badcode;
833 if (icmp6len < sizeof(struct nd_neighbor_advert))
834 goto badlen;
835 if (send_sendso_input_hook != NULL) {
836 error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
837 if (error == 0) {
838 m = NULL;
839 goto freeit;
840 }
841 }
842 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
843 nd6_na_input(m, off, icmp6len);
844 m = n;
845 if (m == NULL)
846 goto freeit;
847 break;
848
849 case ND_REDIRECT:
850 icmp6_ifstat_inc(ifp, ifs6_in_redirect);
851 if (code != 0)
852 goto badcode;
853 if (icmp6len < sizeof(struct nd_redirect))
854 goto badlen;
855 if (send_sendso_input_hook != NULL) {
856 error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
857 if (error == 0) {
858 m = NULL;
859 goto freeit;
860 }
861 }
862 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
863 icmp6_redirect_input(m, off);
864 m = n;
865 if (m == NULL)
866 goto freeit;
867 break;
868
869 case ICMP6_ROUTER_RENUMBERING:
870 if (code != ICMP6_ROUTER_RENUMBERING_COMMAND &&
871 code != ICMP6_ROUTER_RENUMBERING_RESULT)
872 goto badcode;
873 if (icmp6len < sizeof(struct icmp6_router_renum))
874 goto badlen;
875 break;
876
877 default:
878 nd6log((LOG_DEBUG,
879 "icmp6_input: unknown type %d(src=%s, dst=%s, ifid=%d)\n",
880 icmp6->icmp6_type, ip6_sprintf(ip6bufs, &ip6->ip6_src),
881 ip6_sprintf(ip6bufd, &ip6->ip6_dst),
882 ifp ? ifp->if_index : 0));
883 if (icmp6->icmp6_type < ICMP6_ECHO_REQUEST) {
884 /* ICMPv6 error: MUST deliver it by spec... */
885 goto deliver;
886 } else {
887 /* ICMPv6 informational: MUST not deliver */
888 break;
889 }
890 deliver:
891 if (icmp6_notify_error(&m, off, icmp6len) != 0) {
892 /* In this case, m should've been freed. */
893 *mp = NULL;
894 return (IPPROTO_DONE);
895 }
896 break;
897
898 badcode:
899 ICMP6STAT_INC(icp6s_badcode);
900 break;
901
902 badlen:
903 ICMP6STAT_INC(icp6s_badlen);
904 break;
905 }
906
907 /* deliver the packet to appropriate sockets */
908 icmp6_rip6_input(&m, *offp);
909
910 *mp = m;
911 return (IPPROTO_DONE);
912
913 freeit:
914 m_freem(m);
915 *mp = NULL;
916 return (IPPROTO_DONE);
917 }
918
919 static int
icmp6_notify_error(struct mbuf ** mp,int off,int icmp6len)920 icmp6_notify_error(struct mbuf **mp, int off, int icmp6len)
921 {
922 struct mbuf *m;
923 struct icmp6_hdr *icmp6;
924 struct ip6_hdr *eip6;
925 u_int32_t notifymtu;
926 struct sockaddr_in6 icmp6src, icmp6dst;
927
928 m = *mp;
929
930 if (icmp6len < sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr)) {
931 ICMP6STAT_INC(icp6s_tooshort);
932 goto freeit;
933 }
934
935 if (m->m_len < off + sizeof(*icmp6) + sizeof(struct ip6_hdr)) {
936 m = m_pullup(m, off + sizeof(*icmp6) + sizeof(struct ip6_hdr));
937 if (m == NULL) {
938 IP6STAT_INC(ip6s_exthdrtoolong);
939 *mp = m;
940 return (-1);
941 }
942 }
943 icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
944 eip6 = (struct ip6_hdr *)(icmp6 + 1);
945 bzero(&icmp6dst, sizeof(icmp6dst));
946
947 /* Detect the upper level protocol */
948 {
949 u_int8_t nxt = eip6->ip6_nxt;
950 int eoff = off + sizeof(struct icmp6_hdr) +
951 sizeof(struct ip6_hdr);
952 struct ip6ctlparam ip6cp;
953 int icmp6type = icmp6->icmp6_type;
954 struct ip6_frag *fh;
955 struct ip6_rthdr *rth;
956 struct ip6_rthdr0 *rth0;
957 int rthlen;
958
959 while (1) { /* XXX: should avoid infinite loop explicitly? */
960 struct ip6_ext *eh;
961
962 switch (nxt) {
963 case IPPROTO_HOPOPTS:
964 case IPPROTO_DSTOPTS:
965 case IPPROTO_AH:
966 if (m->m_len < eoff + sizeof(struct ip6_ext)) {
967 m = m_pullup(m, eoff +
968 sizeof(struct ip6_ext));
969 if (m == NULL) {
970 IP6STAT_INC(ip6s_exthdrtoolong);
971 *mp = m;
972 return (-1);
973 }
974 }
975 eh = (struct ip6_ext *)
976 (mtod(m, caddr_t) + eoff);
977 if (nxt == IPPROTO_AH)
978 eoff += (eh->ip6e_len + 2) << 2;
979 else
980 eoff += (eh->ip6e_len + 1) << 3;
981 nxt = eh->ip6e_nxt;
982 break;
983 case IPPROTO_ROUTING:
984 /*
985 * When the erroneous packet contains a
986 * routing header, we should examine the
987 * header to determine the final destination.
988 * Otherwise, we can't properly update
989 * information that depends on the final
990 * destination (e.g. path MTU).
991 */
992 if (m->m_len < eoff + sizeof(*rth)) {
993 m = m_pullup(m, eoff + sizeof(*rth));
994 if (m == NULL) {
995 IP6STAT_INC(ip6s_exthdrtoolong);
996 *mp = m;
997 return (-1);
998 }
999 }
1000 rth = (struct ip6_rthdr *)
1001 (mtod(m, caddr_t) + eoff);
1002 rthlen = (rth->ip6r_len + 1) << 3;
1003 /*
1004 * XXX: currently there is no
1005 * officially defined type other
1006 * than type-0.
1007 * Note that if the segment left field
1008 * is 0, all intermediate hops must
1009 * have been passed.
1010 */
1011 if (rth->ip6r_segleft &&
1012 rth->ip6r_type == IPV6_RTHDR_TYPE_0) {
1013 int hops;
1014
1015 if (m->m_len < eoff + rthlen) {
1016 m = m_pullup(m, eoff + rthlen);
1017 if (m == NULL) {
1018 IP6STAT_INC(
1019 ip6s_exthdrtoolong);
1020 *mp = m;
1021 return (-1);
1022 }
1023 }
1024 rth0 = (struct ip6_rthdr0 *)
1025 (mtod(m, caddr_t) + eoff);
1026
1027 /* just ignore a bogus header */
1028 if ((rth0->ip6r0_len % 2) == 0 &&
1029 (hops = rth0->ip6r0_len/2))
1030 icmp6dst.sin6_addr = *((struct in6_addr *)(rth0 + 1) + (hops - 1));
1031 }
1032 eoff += rthlen;
1033 nxt = rth->ip6r_nxt;
1034 break;
1035 case IPPROTO_FRAGMENT:
1036 if (m->m_len < eoff + sizeof(struct ip6_frag)) {
1037 m = m_pullup(m, eoff +
1038 sizeof(struct ip6_frag));
1039 if (m == NULL) {
1040 IP6STAT_INC(ip6s_exthdrtoolong);
1041 *mp = m;
1042 return (-1);
1043 }
1044 }
1045 fh = (struct ip6_frag *)(mtod(m, caddr_t) +
1046 eoff);
1047 /*
1048 * Data after a fragment header is meaningless
1049 * unless it is the first fragment, but
1050 * we'll go to the notify label for path MTU
1051 * discovery.
1052 */
1053 if (fh->ip6f_offlg & IP6F_OFF_MASK)
1054 goto notify;
1055
1056 eoff += sizeof(struct ip6_frag);
1057 nxt = fh->ip6f_nxt;
1058 break;
1059 default:
1060 /*
1061 * This case includes ESP and the No Next
1062 * Header. In such cases going to the notify
1063 * label does not have any meaning
1064 * (i.e. ctlfunc will be NULL), but we go
1065 * anyway since we might have to update
1066 * path MTU information.
1067 */
1068 goto notify;
1069 }
1070 }
1071 notify:
1072 icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
1073
1074 /*
1075 * retrieve parameters from the inner IPv6 header, and convert
1076 * them into sockaddr structures.
1077 * XXX: there is no guarantee that the source or destination
1078 * addresses of the inner packet are in the same scope as
1079 * the addresses of the icmp packet. But there is no other
1080 * way to determine the zone.
1081 */
1082 eip6 = (struct ip6_hdr *)(icmp6 + 1);
1083
1084 /*
1085 * Protocol layers can't do anything useful with unspecified
1086 * addresses.
1087 */
1088 if (IN6_IS_ADDR_UNSPECIFIED(&eip6->ip6_src) ||
1089 IN6_IS_ADDR_UNSPECIFIED(&eip6->ip6_dst))
1090 goto freeit;
1091
1092 icmp6dst.sin6_len = sizeof(struct sockaddr_in6);
1093 icmp6dst.sin6_family = AF_INET6;
1094 if (IN6_IS_ADDR_UNSPECIFIED(&icmp6dst.sin6_addr))
1095 icmp6dst.sin6_addr = eip6->ip6_dst;
1096 if (in6_setscope(&icmp6dst.sin6_addr, m->m_pkthdr.rcvif, NULL))
1097 goto freeit;
1098 bzero(&icmp6src, sizeof(icmp6src));
1099 icmp6src.sin6_len = sizeof(struct sockaddr_in6);
1100 icmp6src.sin6_family = AF_INET6;
1101 icmp6src.sin6_addr = eip6->ip6_src;
1102 if (in6_setscope(&icmp6src.sin6_addr, m->m_pkthdr.rcvif, NULL))
1103 goto freeit;
1104 icmp6src.sin6_flowinfo =
1105 (eip6->ip6_flow & IPV6_FLOWLABEL_MASK);
1106
1107 ip6cp.ip6c_m = m;
1108 ip6cp.ip6c_icmp6 = icmp6;
1109 ip6cp.ip6c_ip6 = (struct ip6_hdr *)(icmp6 + 1);
1110 ip6cp.ip6c_off = eoff;
1111 ip6cp.ip6c_finaldst = &icmp6dst;
1112 ip6cp.ip6c_src = &icmp6src;
1113 ip6cp.ip6c_nxt = nxt;
1114
1115 if (icmp6type == ICMP6_PACKET_TOO_BIG) {
1116 notifymtu = ntohl(icmp6->icmp6_mtu);
1117 ip6cp.ip6c_cmdarg = (void *)¬ifymtu;
1118 icmp6_mtudisc_update(&ip6cp, 1); /*XXX*/
1119 }
1120
1121 if (ip6_ctlprotox[nxt] != NULL)
1122 ip6_ctlprotox[nxt](&ip6cp);
1123 }
1124 *mp = m;
1125 return (0);
1126
1127 freeit:
1128 m_freem(m);
1129 *mp = NULL;
1130 return (-1);
1131 }
1132
1133 void
icmp6_mtudisc_update(struct ip6ctlparam * ip6cp,int validated)1134 icmp6_mtudisc_update(struct ip6ctlparam *ip6cp, int validated)
1135 {
1136 struct in6_addr *dst = &ip6cp->ip6c_finaldst->sin6_addr;
1137 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6;
1138 struct mbuf *m = ip6cp->ip6c_m; /* will be necessary for scope issue */
1139 u_int mtu = ntohl(icmp6->icmp6_mtu);
1140 struct in_conninfo inc;
1141 uint32_t max_mtu;
1142
1143 #if 0
1144 /*
1145 * RFC2460 section 5, last paragraph.
1146 * even though minimum link MTU for IPv6 is IPV6_MMTU,
1147 * we may see ICMPv6 too big with mtu < IPV6_MMTU
1148 * due to packet translator in the middle.
1149 * see ip6_output() and ip6_getpmtu() "alwaysfrag" case for
1150 * special handling.
1151 */
1152 if (mtu < IPV6_MMTU)
1153 return;
1154 #endif
1155
1156 /*
1157 * we reject ICMPv6 too big with abnormally small value.
1158 * XXX what is the good definition of "abnormally small"?
1159 */
1160 if (mtu < sizeof(struct ip6_hdr) + sizeof(struct ip6_frag) + 8)
1161 return;
1162
1163 if (!validated)
1164 return;
1165
1166 /*
1167 * In case the suggested mtu is less than IPV6_MMTU, we
1168 * only need to remember that it was for above mentioned
1169 * "alwaysfrag" case.
1170 * Try to be as close to the spec as possible.
1171 */
1172 if (mtu < IPV6_MMTU)
1173 mtu = IPV6_MMTU - 8;
1174
1175 bzero(&inc, sizeof(inc));
1176 inc.inc_fibnum = M_GETFIB(m);
1177 inc.inc_flags |= INC_ISIPV6;
1178 inc.inc6_faddr = *dst;
1179 if (in6_setscope(&inc.inc6_faddr, m->m_pkthdr.rcvif, NULL))
1180 return;
1181
1182 max_mtu = tcp_hc_getmtu(&inc);
1183 if (max_mtu == 0)
1184 max_mtu = tcp_maxmtu6(&inc, NULL);
1185
1186 if (mtu < max_mtu) {
1187 tcp_hc_updatemtu(&inc, mtu);
1188 ICMP6STAT_INC(icp6s_pmtuchg);
1189 }
1190 }
1191
1192 /*
1193 * Process a Node Information Query packet, based on
1194 * draft-ietf-ipngwg-icmp-name-lookups-07.
1195 *
1196 * Spec incompatibilities:
1197 * - IPv6 Subject address handling
1198 * - IPv4 Subject address handling support missing
1199 * - Proxy reply (answer even if it's not for me)
1200 * - joins NI group address at in6_ifattach() time only, does not cope
1201 * with hostname changes by sethostname(3)
1202 */
1203 static struct mbuf *
ni6_input(struct mbuf * m,int off,struct prison * pr)1204 ni6_input(struct mbuf *m, int off, struct prison *pr)
1205 {
1206 struct icmp6_nodeinfo *ni6, *nni6;
1207 struct mbuf *n = NULL;
1208 u_int16_t qtype;
1209 int subjlen;
1210 int replylen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
1211 struct ni_reply_fqdn *fqdn;
1212 int addrs; /* for NI_QTYPE_NODEADDR */
1213 struct ifnet *ifp = NULL; /* for NI_QTYPE_NODEADDR */
1214 struct in6_addr in6_subj; /* subject address */
1215 struct ip6_hdr *ip6;
1216 int oldfqdn = 0; /* if 1, return pascal string (03 draft) */
1217 char *subj = NULL;
1218 struct in6_ifaddr *ia6 = NULL;
1219
1220 ip6 = mtod(m, struct ip6_hdr *);
1221 ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
1222
1223 /*
1224 * Validate IPv6 source address.
1225 * The default configuration MUST be to refuse answering queries from
1226 * global-scope addresses according to RFC4602.
1227 * Notes:
1228 * - it's not very clear what "refuse" means; this implementation
1229 * simply drops it.
1230 * - it's not very easy to identify global-scope (unicast) addresses
1231 * since there are many prefixes for them. It should be safer
1232 * and in practice sufficient to check "all" but loopback and
1233 * link-local (note that site-local unicast was deprecated and
1234 * ULA is defined as global scope-wise)
1235 */
1236 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_GLOBALOK) == 0 &&
1237 !IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) &&
1238 !IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src))
1239 goto bad;
1240
1241 /*
1242 * Validate IPv6 destination address.
1243 *
1244 * The Responder must discard the Query without further processing
1245 * unless it is one of the Responder's unicast or anycast addresses, or
1246 * a link-local scope multicast address which the Responder has joined.
1247 * [RFC4602, Section 5.]
1248 */
1249 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
1250 if (!IN6_IS_ADDR_MC_LINKLOCAL(&ip6->ip6_dst))
1251 goto bad;
1252 /* else it's a link-local multicast, fine */
1253 } else { /* unicast or anycast */
1254 ia6 = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */, false);
1255 if (ia6 == NULL)
1256 goto bad; /* XXX impossible */
1257
1258 if ((ia6->ia6_flags & IN6_IFF_TEMPORARY) &&
1259 !(V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK)) {
1260 nd6log((LOG_DEBUG, "ni6_input: ignore node info to "
1261 "a temporary address in %s:%d",
1262 __FILE__, __LINE__));
1263 goto bad;
1264 }
1265 }
1266
1267 /* validate query Subject field. */
1268 qtype = ntohs(ni6->ni_qtype);
1269 subjlen = m->m_pkthdr.len - off - sizeof(struct icmp6_nodeinfo);
1270 switch (qtype) {
1271 case NI_QTYPE_NOOP:
1272 case NI_QTYPE_SUPTYPES:
1273 /* 07 draft */
1274 if (ni6->ni_code == ICMP6_NI_SUBJ_FQDN && subjlen == 0)
1275 break;
1276 /* FALLTHROUGH */
1277 case NI_QTYPE_FQDN:
1278 case NI_QTYPE_NODEADDR:
1279 case NI_QTYPE_IPV4ADDR:
1280 switch (ni6->ni_code) {
1281 case ICMP6_NI_SUBJ_IPV6:
1282 #if ICMP6_NI_SUBJ_IPV6 != 0
1283 case 0:
1284 #endif
1285 /*
1286 * backward compatibility - try to accept 03 draft
1287 * format, where no Subject is present.
1288 */
1289 if (qtype == NI_QTYPE_FQDN && ni6->ni_code == 0 &&
1290 subjlen == 0) {
1291 oldfqdn++;
1292 break;
1293 }
1294 #if ICMP6_NI_SUBJ_IPV6 != 0
1295 if (ni6->ni_code != ICMP6_NI_SUBJ_IPV6)
1296 goto bad;
1297 #endif
1298
1299 if (subjlen != sizeof(struct in6_addr))
1300 goto bad;
1301
1302 /*
1303 * Validate Subject address.
1304 *
1305 * Not sure what exactly "address belongs to the node"
1306 * means in the spec, is it just unicast, or what?
1307 *
1308 * At this moment we consider Subject address as
1309 * "belong to the node" if the Subject address equals
1310 * to the IPv6 destination address; validation for
1311 * IPv6 destination address should have done enough
1312 * check for us.
1313 *
1314 * We do not do proxy at this moment.
1315 */
1316 m_copydata(m, off + sizeof(struct icmp6_nodeinfo),
1317 subjlen, (caddr_t)&in6_subj);
1318 if (in6_setscope(&in6_subj, m->m_pkthdr.rcvif, NULL))
1319 goto bad;
1320
1321 subj = (char *)&in6_subj;
1322 if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &in6_subj))
1323 break;
1324
1325 /*
1326 * XXX if we are to allow other cases, we should really
1327 * be careful about scope here.
1328 * basically, we should disallow queries toward IPv6
1329 * destination X with subject Y,
1330 * if scope(X) > scope(Y).
1331 * if we allow scope(X) > scope(Y), it will result in
1332 * information leakage across scope boundary.
1333 */
1334 goto bad;
1335
1336 case ICMP6_NI_SUBJ_FQDN:
1337 /*
1338 * Validate Subject name with gethostname(3).
1339 *
1340 * The behavior may need some debate, since:
1341 * - we are not sure if the node has FQDN as
1342 * hostname (returned by gethostname(3)).
1343 * - the code does wildcard match for truncated names.
1344 * however, we are not sure if we want to perform
1345 * wildcard match, if gethostname(3) side has
1346 * truncated hostname.
1347 */
1348 mtx_lock(&pr->pr_mtx);
1349 n = ni6_nametodns(pr->pr_hostname,
1350 strlen(pr->pr_hostname), 0);
1351 mtx_unlock(&pr->pr_mtx);
1352 if (!n || n->m_next || n->m_len == 0)
1353 goto bad;
1354 if (m->m_len < off + sizeof(struct icmp6_nodeinfo) +
1355 subjlen) {
1356 m = m_pullup(m, off +
1357 sizeof(struct icmp6_nodeinfo) + subjlen);
1358 if (m == NULL) {
1359 IP6STAT_INC(ip6s_exthdrtoolong);
1360 goto bad;
1361 }
1362 }
1363 /* ip6 possibly invalid but not used after. */
1364 ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
1365 subj = (char *)(mtod(m, caddr_t) + off +
1366 sizeof(struct icmp6_nodeinfo));
1367 if (!ni6_dnsmatch(subj, subjlen, mtod(n, const char *),
1368 n->m_len)) {
1369 goto bad;
1370 }
1371 m_freem(n);
1372 n = NULL;
1373 break;
1374
1375 case ICMP6_NI_SUBJ_IPV4: /* XXX: to be implemented? */
1376 default:
1377 goto bad;
1378 }
1379 break;
1380 }
1381
1382 /* refuse based on configuration. XXX ICMP6_NI_REFUSED? */
1383 switch (qtype) {
1384 case NI_QTYPE_FQDN:
1385 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_FQDNOK) == 0)
1386 goto bad;
1387 break;
1388 case NI_QTYPE_NODEADDR:
1389 case NI_QTYPE_IPV4ADDR:
1390 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_NODEADDROK) == 0)
1391 goto bad;
1392 break;
1393 }
1394
1395 /* guess reply length */
1396 switch (qtype) {
1397 case NI_QTYPE_NOOP:
1398 break; /* no reply data */
1399 case NI_QTYPE_SUPTYPES:
1400 replylen += sizeof(u_int32_t);
1401 break;
1402 case NI_QTYPE_FQDN:
1403 /* XXX will append an mbuf */
1404 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
1405 break;
1406 case NI_QTYPE_NODEADDR:
1407 addrs = ni6_addrs(ni6, m, &ifp, (struct in6_addr *)subj);
1408 if ((replylen += addrs * (sizeof(struct in6_addr) +
1409 sizeof(u_int32_t))) > MCLBYTES)
1410 replylen = MCLBYTES; /* XXX: will truncate pkt later */
1411 break;
1412 case NI_QTYPE_IPV4ADDR:
1413 /* unsupported - should respond with unknown Qtype? */
1414 break;
1415 default:
1416 /*
1417 * XXX: We must return a reply with the ICMP6 code
1418 * `unknown Qtype' in this case. However we regard the case
1419 * as an FQDN query for backward compatibility.
1420 * Older versions set a random value to this field,
1421 * so it rarely varies in the defined qtypes.
1422 * But the mechanism is not reliable...
1423 * maybe we should obsolete older versions.
1424 */
1425 qtype = NI_QTYPE_FQDN;
1426 /* XXX will append an mbuf */
1427 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
1428 oldfqdn++;
1429 break;
1430 }
1431
1432 /* Allocate an mbuf to reply. */
1433 if (replylen > MCLBYTES) {
1434 /*
1435 * XXX: should we try to allocate more? But MCLBYTES
1436 * is probably much larger than IPV6_MMTU...
1437 */
1438 goto bad;
1439 }
1440 if (replylen > MHLEN)
1441 n = m_getcl(M_NOWAIT, m->m_type, M_PKTHDR);
1442 else
1443 n = m_gethdr(M_NOWAIT, m->m_type);
1444 if (n == NULL) {
1445 m_freem(m);
1446 return (NULL);
1447 }
1448 m_move_pkthdr(n, m); /* just for recvif and FIB */
1449 n->m_pkthdr.len = n->m_len = replylen;
1450
1451 /* copy mbuf header and IPv6 + Node Information base headers */
1452 bcopy(mtod(m, caddr_t), mtod(n, caddr_t), sizeof(struct ip6_hdr));
1453 nni6 = (struct icmp6_nodeinfo *)(mtod(n, struct ip6_hdr *) + 1);
1454 bcopy((caddr_t)ni6, (caddr_t)nni6, sizeof(struct icmp6_nodeinfo));
1455
1456 /* qtype dependent procedure */
1457 switch (qtype) {
1458 case NI_QTYPE_NOOP:
1459 nni6->ni_code = ICMP6_NI_SUCCESS;
1460 nni6->ni_flags = 0;
1461 break;
1462 case NI_QTYPE_SUPTYPES:
1463 {
1464 u_int32_t v;
1465 nni6->ni_code = ICMP6_NI_SUCCESS;
1466 nni6->ni_flags = htons(0x0000); /* raw bitmap */
1467 /* supports NOOP, SUPTYPES, FQDN, and NODEADDR */
1468 v = (u_int32_t)htonl(0x0000000f);
1469 bcopy(&v, nni6 + 1, sizeof(u_int32_t));
1470 break;
1471 }
1472 case NI_QTYPE_FQDN:
1473 nni6->ni_code = ICMP6_NI_SUCCESS;
1474 fqdn = (struct ni_reply_fqdn *)(mtod(n, caddr_t) +
1475 sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo));
1476 nni6->ni_flags = 0; /* XXX: meaningless TTL */
1477 fqdn->ni_fqdn_ttl = 0; /* ditto. */
1478 /*
1479 * XXX do we really have FQDN in hostname?
1480 */
1481 mtx_lock(&pr->pr_mtx);
1482 n->m_next = ni6_nametodns(pr->pr_hostname,
1483 strlen(pr->pr_hostname), oldfqdn);
1484 mtx_unlock(&pr->pr_mtx);
1485 if (n->m_next == NULL)
1486 goto bad;
1487 /* XXX we assume that n->m_next is not a chain */
1488 if (n->m_next->m_next != NULL)
1489 goto bad;
1490 n->m_pkthdr.len += n->m_next->m_len;
1491 break;
1492 case NI_QTYPE_NODEADDR:
1493 {
1494 int lenlim, copied;
1495
1496 nni6->ni_code = ICMP6_NI_SUCCESS;
1497 n->m_pkthdr.len = n->m_len =
1498 sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
1499 lenlim = M_TRAILINGSPACE(n);
1500 copied = ni6_store_addrs(ni6, nni6, ifp, lenlim);
1501 /* XXX: reset mbuf length */
1502 n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
1503 sizeof(struct icmp6_nodeinfo) + copied;
1504 break;
1505 }
1506 default:
1507 break; /* XXX impossible! */
1508 }
1509
1510 nni6->ni_type = ICMP6_NI_REPLY;
1511 m_freem(m);
1512 return (n);
1513
1514 bad:
1515 m_freem(m);
1516 if (n)
1517 m_freem(n);
1518 return (NULL);
1519 }
1520
1521 /*
1522 * make a mbuf with DNS-encoded string. no compression support.
1523 *
1524 * XXX names with less than 2 dots (like "foo" or "foo.section") will be
1525 * treated as truncated name (two \0 at the end). this is a wild guess.
1526 *
1527 * old - return pascal string if non-zero
1528 */
1529 static struct mbuf *
ni6_nametodns(const char * name,int namelen,int old)1530 ni6_nametodns(const char *name, int namelen, int old)
1531 {
1532 struct mbuf *m;
1533 char *cp, *ep;
1534 const char *p, *q;
1535 int i, len, nterm;
1536
1537 if (old)
1538 len = namelen + 1;
1539 else
1540 len = MCLBYTES;
1541
1542 /* Because MAXHOSTNAMELEN is usually 256, we use cluster mbuf. */
1543 if (len > MLEN)
1544 m = m_getcl(M_NOWAIT, MT_DATA, 0);
1545 else
1546 m = m_get(M_NOWAIT, MT_DATA);
1547 if (m == NULL)
1548 goto fail;
1549
1550 if (old) {
1551 m->m_len = len;
1552 *mtod(m, char *) = namelen;
1553 bcopy(name, mtod(m, char *) + 1, namelen);
1554 return m;
1555 } else {
1556 m->m_len = 0;
1557 cp = mtod(m, char *);
1558 ep = mtod(m, char *) + M_TRAILINGSPACE(m);
1559
1560 /* if not certain about my name, return empty buffer */
1561 if (namelen == 0)
1562 return m;
1563
1564 /*
1565 * guess if it looks like shortened hostname, or FQDN.
1566 * shortened hostname needs two trailing "\0".
1567 */
1568 i = 0;
1569 for (p = name; p < name + namelen; p++) {
1570 if (*p && *p == '.')
1571 i++;
1572 }
1573 if (i < 2)
1574 nterm = 2;
1575 else
1576 nterm = 1;
1577
1578 p = name;
1579 while (cp < ep && p < name + namelen) {
1580 i = 0;
1581 for (q = p; q < name + namelen && *q && *q != '.'; q++)
1582 i++;
1583 /* result does not fit into mbuf */
1584 if (cp + i + 1 >= ep)
1585 goto fail;
1586 /*
1587 * DNS label length restriction, RFC1035 page 8.
1588 * "i == 0" case is included here to avoid returning
1589 * 0-length label on "foo..bar".
1590 */
1591 if (i <= 0 || i >= 64)
1592 goto fail;
1593 *cp++ = i;
1594 bcopy(p, cp, i);
1595 cp += i;
1596 p = q;
1597 if (p < name + namelen && *p == '.')
1598 p++;
1599 }
1600 /* termination */
1601 if (cp + nterm >= ep)
1602 goto fail;
1603 while (nterm-- > 0)
1604 *cp++ = '\0';
1605 m->m_len = cp - mtod(m, char *);
1606 return m;
1607 }
1608
1609 panic("should not reach here");
1610 /* NOTREACHED */
1611
1612 fail:
1613 if (m)
1614 m_freem(m);
1615 return NULL;
1616 }
1617
1618 /*
1619 * check if two DNS-encoded string matches. takes care of truncated
1620 * form (with \0\0 at the end). no compression support.
1621 * XXX upper/lowercase match (see RFC2065)
1622 */
1623 static int
ni6_dnsmatch(const char * a,int alen,const char * b,int blen)1624 ni6_dnsmatch(const char *a, int alen, const char *b, int blen)
1625 {
1626 const char *a0, *b0;
1627 int l;
1628
1629 /* simplest case - need validation? */
1630 if (alen == blen && bcmp(a, b, alen) == 0)
1631 return 1;
1632
1633 a0 = a;
1634 b0 = b;
1635
1636 /* termination is mandatory */
1637 if (alen < 2 || blen < 2)
1638 return 0;
1639 if (a0[alen - 1] != '\0' || b0[blen - 1] != '\0')
1640 return 0;
1641 alen--;
1642 blen--;
1643
1644 while (a - a0 < alen && b - b0 < blen) {
1645 if (a - a0 + 1 > alen || b - b0 + 1 > blen)
1646 return 0;
1647
1648 if ((signed char)a[0] < 0 || (signed char)b[0] < 0)
1649 return 0;
1650 /* we don't support compression yet */
1651 if (a[0] >= 64 || b[0] >= 64)
1652 return 0;
1653
1654 /* truncated case */
1655 if (a[0] == 0 && a - a0 == alen - 1)
1656 return 1;
1657 if (b[0] == 0 && b - b0 == blen - 1)
1658 return 1;
1659 if (a[0] == 0 || b[0] == 0)
1660 return 0;
1661
1662 if (a[0] != b[0])
1663 return 0;
1664 l = a[0];
1665 if (a - a0 + 1 + l > alen || b - b0 + 1 + l > blen)
1666 return 0;
1667 if (bcmp(a + 1, b + 1, l) != 0)
1668 return 0;
1669
1670 a += 1 + l;
1671 b += 1 + l;
1672 }
1673
1674 if (a - a0 == alen && b - b0 == blen)
1675 return 1;
1676 else
1677 return 0;
1678 }
1679
1680 /*
1681 * calculate the number of addresses to be returned in the node info reply.
1682 */
1683 static int
ni6_addrs(struct icmp6_nodeinfo * ni6,struct mbuf * m,struct ifnet ** ifpp,struct in6_addr * subj)1684 ni6_addrs(struct icmp6_nodeinfo *ni6, struct mbuf *m, struct ifnet **ifpp,
1685 struct in6_addr *subj)
1686 {
1687 struct ifnet *ifp;
1688 struct in6_ifaddr *ifa6;
1689 struct ifaddr *ifa;
1690 int addrs = 0, addrsofif, iffound = 0;
1691 int niflags = ni6->ni_flags;
1692
1693 NET_EPOCH_ASSERT();
1694
1695 if ((niflags & NI_NODEADDR_FLAG_ALL) == 0) {
1696 switch (ni6->ni_code) {
1697 case ICMP6_NI_SUBJ_IPV6:
1698 if (subj == NULL) /* must be impossible... */
1699 return (0);
1700 break;
1701 default:
1702 /*
1703 * XXX: we only support IPv6 subject address for
1704 * this Qtype.
1705 */
1706 return (0);
1707 }
1708 }
1709
1710 CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
1711 addrsofif = 0;
1712 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1713 if (ifa->ifa_addr->sa_family != AF_INET6)
1714 continue;
1715 ifa6 = (struct in6_ifaddr *)ifa;
1716
1717 if ((niflags & NI_NODEADDR_FLAG_ALL) == 0 &&
1718 IN6_ARE_ADDR_EQUAL(subj, &ifa6->ia_addr.sin6_addr))
1719 iffound = 1;
1720
1721 /*
1722 * IPv4-mapped addresses can only be returned by a
1723 * Node Information proxy, since they represent
1724 * addresses of IPv4-only nodes, which perforce do
1725 * not implement this protocol.
1726 * [icmp-name-lookups-07, Section 5.4]
1727 * So we don't support NI_NODEADDR_FLAG_COMPAT in
1728 * this function at this moment.
1729 */
1730
1731 /* What do we have to do about ::1? */
1732 switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1733 case IPV6_ADDR_SCOPE_LINKLOCAL:
1734 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
1735 continue;
1736 break;
1737 case IPV6_ADDR_SCOPE_SITELOCAL:
1738 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
1739 continue;
1740 break;
1741 case IPV6_ADDR_SCOPE_GLOBAL:
1742 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
1743 continue;
1744 break;
1745 default:
1746 continue;
1747 }
1748
1749 /*
1750 * check if anycast is okay.
1751 * XXX: just experimental. not in the spec.
1752 */
1753 if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
1754 (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
1755 continue; /* we need only unicast addresses */
1756 if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
1757 (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
1758 continue;
1759 }
1760 addrsofif++; /* count the address */
1761 }
1762 if (iffound) {
1763 *ifpp = ifp;
1764 return (addrsofif);
1765 }
1766
1767 addrs += addrsofif;
1768 }
1769
1770 return (addrs);
1771 }
1772
1773 static int
ni6_store_addrs(struct icmp6_nodeinfo * ni6,struct icmp6_nodeinfo * nni6,struct ifnet * ifp0,int resid)1774 ni6_store_addrs(struct icmp6_nodeinfo *ni6, struct icmp6_nodeinfo *nni6,
1775 struct ifnet *ifp0, int resid)
1776 {
1777 struct ifnet *ifp;
1778 struct in6_ifaddr *ifa6;
1779 struct ifaddr *ifa;
1780 struct ifnet *ifp_dep = NULL;
1781 int copied = 0, allow_deprecated = 0;
1782 u_char *cp = (u_char *)(nni6 + 1);
1783 int niflags = ni6->ni_flags;
1784 u_int32_t ltime;
1785
1786 NET_EPOCH_ASSERT();
1787
1788 if (ifp0 == NULL && !(niflags & NI_NODEADDR_FLAG_ALL))
1789 return (0); /* needless to copy */
1790
1791 ifp = ifp0 ? ifp0 : CK_STAILQ_FIRST(&V_ifnet);
1792 again:
1793
1794 for (; ifp; ifp = CK_STAILQ_NEXT(ifp, if_link)) {
1795 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1796 if (ifa->ifa_addr->sa_family != AF_INET6)
1797 continue;
1798 ifa6 = (struct in6_ifaddr *)ifa;
1799
1800 if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) != 0 &&
1801 allow_deprecated == 0) {
1802 /*
1803 * prefererred address should be put before
1804 * deprecated addresses.
1805 */
1806
1807 /* record the interface for later search */
1808 if (ifp_dep == NULL)
1809 ifp_dep = ifp;
1810
1811 continue;
1812 } else if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) == 0 &&
1813 allow_deprecated != 0)
1814 continue; /* we now collect deprecated addrs */
1815
1816 /* What do we have to do about ::1? */
1817 switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1818 case IPV6_ADDR_SCOPE_LINKLOCAL:
1819 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
1820 continue;
1821 break;
1822 case IPV6_ADDR_SCOPE_SITELOCAL:
1823 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
1824 continue;
1825 break;
1826 case IPV6_ADDR_SCOPE_GLOBAL:
1827 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
1828 continue;
1829 break;
1830 default:
1831 continue;
1832 }
1833
1834 /*
1835 * check if anycast is okay.
1836 * XXX: just experimental. not in the spec.
1837 */
1838 if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
1839 (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
1840 continue;
1841 if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
1842 (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
1843 continue;
1844 }
1845
1846 /* now we can copy the address */
1847 if (resid < sizeof(struct in6_addr) +
1848 sizeof(u_int32_t)) {
1849 /*
1850 * We give up much more copy.
1851 * Set the truncate flag and return.
1852 */
1853 nni6->ni_flags |= NI_NODEADDR_FLAG_TRUNCATE;
1854 return (copied);
1855 }
1856
1857 /*
1858 * Set the TTL of the address.
1859 * The TTL value should be one of the following
1860 * according to the specification:
1861 *
1862 * 1. The remaining lifetime of a DHCP lease on the
1863 * address, or
1864 * 2. The remaining Valid Lifetime of a prefix from
1865 * which the address was derived through Stateless
1866 * Autoconfiguration.
1867 *
1868 * Note that we currently do not support stateful
1869 * address configuration by DHCPv6, so the former
1870 * case can't happen.
1871 */
1872 if (ifa6->ia6_lifetime.ia6t_expire == 0)
1873 ltime = ND6_INFINITE_LIFETIME;
1874 else {
1875 if (ifa6->ia6_lifetime.ia6t_expire >
1876 time_uptime)
1877 ltime = htonl(ifa6->ia6_lifetime.ia6t_expire - time_uptime);
1878 else
1879 ltime = 0;
1880 }
1881
1882 bcopy(<ime, cp, sizeof(u_int32_t));
1883 cp += sizeof(u_int32_t);
1884
1885 /* copy the address itself */
1886 bcopy(&ifa6->ia_addr.sin6_addr, cp,
1887 sizeof(struct in6_addr));
1888 in6_clearscope((struct in6_addr *)cp); /* XXX */
1889 cp += sizeof(struct in6_addr);
1890
1891 resid -= (sizeof(struct in6_addr) + sizeof(u_int32_t));
1892 copied += (sizeof(struct in6_addr) + sizeof(u_int32_t));
1893 }
1894 if (ifp0) /* we need search only on the specified IF */
1895 break;
1896 }
1897
1898 if (allow_deprecated == 0 && ifp_dep != NULL) {
1899 ifp = ifp_dep;
1900 allow_deprecated = 1;
1901
1902 goto again;
1903 }
1904
1905 return (copied);
1906 }
1907
1908 static bool
icmp6_rip6_match(const struct inpcb * inp,void * v)1909 icmp6_rip6_match(const struct inpcb *inp, void *v)
1910 {
1911 struct ip6_hdr *ip6 = v;
1912
1913 if ((inp->inp_vflag & INP_IPV6) == 0)
1914 return (false);
1915 if (inp->inp_ip_p != IPPROTO_ICMPV6)
1916 return (false);
1917 if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) &&
1918 !IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr, &ip6->ip6_dst))
1919 return (false);
1920 if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr) &&
1921 !IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr, &ip6->ip6_src))
1922 return (false);
1923 return (true);
1924 }
1925
1926 /*
1927 * XXX almost dup'ed code with rip6_input.
1928 */
1929 static int
icmp6_rip6_input(struct mbuf ** mp,int off)1930 icmp6_rip6_input(struct mbuf **mp, int off)
1931 {
1932 struct mbuf *n, *m = *mp;
1933 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1934 struct inpcb_iterator inpi = INP_ITERATOR(&V_ripcbinfo,
1935 INPLOOKUP_RLOCKPCB, icmp6_rip6_match, ip6);
1936 struct inpcb *inp;
1937 struct sockaddr_in6 fromsa;
1938 struct icmp6_hdr *icmp6;
1939 struct mbuf *opts = NULL;
1940 int delivered = 0, fib;
1941
1942 /* This is assumed to be safe; icmp6_input() does a pullup. */
1943 icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
1944
1945 /*
1946 * XXX: the address may have embedded scope zone ID, which should be
1947 * hidden from applications.
1948 */
1949 bzero(&fromsa, sizeof(fromsa));
1950 fromsa.sin6_family = AF_INET6;
1951 fromsa.sin6_len = sizeof(struct sockaddr_in6);
1952 fromsa.sin6_addr = ip6->ip6_src;
1953 if (sa6_recoverscope(&fromsa)) {
1954 m_freem(m);
1955 *mp = NULL;
1956 return (IPPROTO_DONE);
1957 }
1958
1959 fib = M_GETFIB(m);
1960
1961 while ((inp = inp_next(&inpi)) != NULL) {
1962 if (V_rip_bind_all_fibs == 0 && fib != inp->inp_inc.inc_fibnum)
1963 /*
1964 * Sockets bound to a specific FIB can only receive
1965 * packets from that FIB.
1966 */
1967 continue;
1968 if (ICMP6_FILTER_WILLBLOCK(icmp6->icmp6_type,
1969 inp->in6p_icmp6filt))
1970 continue;
1971 /*
1972 * Recent network drivers tend to allocate a single
1973 * mbuf cluster, rather than to make a couple of
1974 * mbufs without clusters. Also, since the IPv6 code
1975 * path tries to avoid m_pullup(), it is highly
1976 * probable that we still have an mbuf cluster here
1977 * even though the necessary length can be stored in an
1978 * mbuf's internal buffer.
1979 * Meanwhile, the default size of the receive socket
1980 * buffer for raw sockets is not so large. This means
1981 * the possibility of packet loss is relatively higher
1982 * than before. To avoid this scenario, we copy the
1983 * received data to a separate mbuf that does not use
1984 * a cluster, if possible.
1985 * XXX: it is better to copy the data after stripping
1986 * intermediate headers.
1987 */
1988 if ((m->m_flags & M_EXT) && m->m_next == NULL &&
1989 m->m_len <= MHLEN) {
1990 n = m_get(M_NOWAIT, m->m_type);
1991 if (n != NULL) {
1992 if (m_dup_pkthdr(n, m, M_NOWAIT)) {
1993 bcopy(m->m_data, n->m_data, m->m_len);
1994 n->m_len = m->m_len;
1995 } else {
1996 m_free(n);
1997 n = NULL;
1998 }
1999 }
2000 } else
2001 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
2002 if (n == NULL)
2003 continue;
2004 if (inp->inp_flags & INP_CONTROLOPTS)
2005 ip6_savecontrol(inp, n, &opts);
2006 /* strip intermediate headers */
2007 m_adj(n, off);
2008 SOCKBUF_LOCK(&inp->inp_socket->so_rcv);
2009 if (sbappendaddr_locked(&inp->inp_socket->so_rcv,
2010 (struct sockaddr *)&fromsa, n, opts) == 0) {
2011 soroverflow_locked(inp->inp_socket);
2012 m_freem(n);
2013 if (opts)
2014 m_freem(opts);
2015 } else {
2016 sorwakeup_locked(inp->inp_socket);
2017 delivered++;
2018 }
2019 opts = NULL;
2020 }
2021 m_freem(m);
2022 *mp = NULL;
2023 if (delivered == 0)
2024 IP6STAT_DEC(ip6s_delivered);
2025 return (IPPROTO_DONE);
2026 }
2027
2028 /*
2029 * Reflect the ip6 packet back to the source.
2030 * OFF points to the icmp6 header, counted from the top of the mbuf.
2031 */
2032 static void
icmp6_reflect(struct mbuf * m,size_t off)2033 icmp6_reflect(struct mbuf *m, size_t off)
2034 {
2035 struct in6_addr src6, *srcp;
2036 struct ip6_hdr *ip6;
2037 struct icmp6_hdr *icmp6;
2038 struct in6_ifaddr *ia = NULL;
2039 struct ifnet *outif = NULL;
2040 int plen;
2041 int type, code, hlim;
2042
2043 /* too short to reflect */
2044 if (off < sizeof(struct ip6_hdr)) {
2045 nd6log((LOG_DEBUG,
2046 "sanity fail: off=%lx, sizeof(ip6)=%lx in %s:%d\n",
2047 (u_long)off, (u_long)sizeof(struct ip6_hdr),
2048 __FILE__, __LINE__));
2049 goto bad;
2050 }
2051
2052 /*
2053 * If there are extra headers between IPv6 and ICMPv6, strip
2054 * off that header first.
2055 */
2056 #ifdef DIAGNOSTIC
2057 if (sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) > MHLEN)
2058 panic("assumption failed in icmp6_reflect");
2059 #endif
2060 if (off > sizeof(struct ip6_hdr)) {
2061 size_t l;
2062 struct ip6_hdr nip6;
2063
2064 l = off - sizeof(struct ip6_hdr);
2065 m_copydata(m, 0, sizeof(nip6), (caddr_t)&nip6);
2066 m_adj(m, l);
2067 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
2068 if (m->m_len < l) {
2069 if ((m = m_pullup(m, l)) == NULL)
2070 return;
2071 }
2072 bcopy((caddr_t)&nip6, mtod(m, caddr_t), sizeof(nip6));
2073 } else /* off == sizeof(struct ip6_hdr) */ {
2074 size_t l;
2075 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
2076 if (m->m_len < l) {
2077 if ((m = m_pullup(m, l)) == NULL)
2078 return;
2079 }
2080 }
2081 plen = m->m_pkthdr.len - sizeof(struct ip6_hdr);
2082 ip6 = mtod(m, struct ip6_hdr *);
2083 ip6->ip6_nxt = IPPROTO_ICMPV6;
2084 icmp6 = (struct icmp6_hdr *)(ip6 + 1);
2085 type = icmp6->icmp6_type; /* keep type for statistics */
2086 code = icmp6->icmp6_code; /* ditto. */
2087 hlim = 0;
2088 srcp = NULL;
2089
2090 /*
2091 * If the incoming packet was addressed directly to us (i.e. unicast),
2092 * use dst as the src for the reply.
2093 * The IN6_IFF_NOTREADY case should be VERY rare, but is possible
2094 * (for example) when we encounter an error while forwarding procedure
2095 * destined to a duplicated address of ours.
2096 */
2097 if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
2098 ia = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */, false);
2099 if (ia != NULL && !(ia->ia6_flags &
2100 (IN6_IFF_ANYCAST|IN6_IFF_NOTREADY))) {
2101 src6 = ia->ia_addr.sin6_addr;
2102 srcp = &src6;
2103
2104 if (m->m_pkthdr.rcvif != NULL) {
2105 /* XXX: This may not be the outgoing interface */
2106 hlim = ND_IFINFO(m->m_pkthdr.rcvif)->chlim;
2107 } else
2108 hlim = V_ip6_defhlim;
2109 }
2110 }
2111
2112 if (srcp == NULL) {
2113 int error;
2114 struct in6_addr dst6;
2115 uint32_t scopeid;
2116
2117 /*
2118 * This case matches to multicasts, our anycast, or unicasts
2119 * that we do not own. Select a source address based on the
2120 * source address of the erroneous packet.
2121 */
2122 in6_splitscope(&ip6->ip6_src, &dst6, &scopeid);
2123 error = in6_selectsrc_addr(M_GETFIB(m), &dst6,
2124 scopeid, NULL, &src6, &hlim);
2125
2126 if (error) {
2127 char ip6buf[INET6_ADDRSTRLEN];
2128 nd6log((LOG_DEBUG,
2129 "icmp6_reflect: source can't be determined: "
2130 "dst=%s, error=%d\n",
2131 ip6_sprintf(ip6buf, &ip6->ip6_dst), error));
2132 goto bad;
2133 }
2134 srcp = &src6;
2135 }
2136 /*
2137 * ip6_input() drops a packet if its src is multicast.
2138 * So, the src is never multicast.
2139 */
2140 ip6->ip6_dst = ip6->ip6_src;
2141 ip6->ip6_src = *srcp;
2142 ip6->ip6_flow = 0;
2143 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
2144 ip6->ip6_vfc |= IPV6_VERSION;
2145 ip6->ip6_nxt = IPPROTO_ICMPV6;
2146 ip6->ip6_hlim = hlim;
2147
2148 icmp6->icmp6_cksum = 0;
2149 icmp6->icmp6_cksum = in6_cksum(m, IPPROTO_ICMPV6,
2150 sizeof(struct ip6_hdr), plen);
2151
2152 /*
2153 * XXX option handling
2154 */
2155
2156 m->m_flags &= ~(M_BCAST|M_MCAST);
2157 m->m_pkthdr.rcvif = NULL;
2158 ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
2159 if (outif)
2160 icmp6_ifoutstat_inc(outif, type, code);
2161
2162 return;
2163
2164 bad:
2165 m_freem(m);
2166 return;
2167 }
2168
2169 static const char *
icmp6_redirect_diag(struct in6_addr * src6,struct in6_addr * dst6,struct in6_addr * tgt6)2170 icmp6_redirect_diag(struct in6_addr *src6, struct in6_addr *dst6,
2171 struct in6_addr *tgt6)
2172 {
2173 static char buf[1024];
2174 char ip6bufs[INET6_ADDRSTRLEN];
2175 char ip6bufd[INET6_ADDRSTRLEN];
2176 char ip6buft[INET6_ADDRSTRLEN];
2177 snprintf(buf, sizeof(buf), "(src=%s dst=%s tgt=%s)",
2178 ip6_sprintf(ip6bufs, src6), ip6_sprintf(ip6bufd, dst6),
2179 ip6_sprintf(ip6buft, tgt6));
2180 return buf;
2181 }
2182
2183 void
icmp6_redirect_input(struct mbuf * m,int off)2184 icmp6_redirect_input(struct mbuf *m, int off)
2185 {
2186 struct ifnet *ifp;
2187 struct ip6_hdr *ip6;
2188 struct nd_redirect *nd_rd;
2189 struct in6_addr src6, redtgt6, reddst6;
2190 union nd_opts ndopts;
2191 char ip6buf[INET6_ADDRSTRLEN];
2192 char *lladdr;
2193 int icmp6len, is_onlink, is_router, lladdrlen;
2194
2195 M_ASSERTPKTHDR(m);
2196 KASSERT(m->m_pkthdr.rcvif != NULL, ("%s: no rcvif", __func__));
2197
2198 /* XXX if we are router, we don't update route by icmp6 redirect */
2199 if (V_ip6_forwarding)
2200 goto freeit;
2201 if (!V_icmp6_rediraccept)
2202 goto freeit;
2203
2204 /* RFC 6980: Nodes MUST silently ignore fragments */
2205 if(m->m_flags & M_FRAGMENTED)
2206 goto freeit;
2207
2208 ip6 = mtod(m, struct ip6_hdr *);
2209 icmp6len = ntohs(ip6->ip6_plen);
2210 if (m->m_len < off + icmp6len) {
2211 m = m_pullup(m, off + icmp6len);
2212 if (m == NULL) {
2213 IP6STAT_INC(ip6s_exthdrtoolong);
2214 return;
2215 }
2216 }
2217 ip6 = mtod(m, struct ip6_hdr *);
2218 nd_rd = (struct nd_redirect *)((caddr_t)ip6 + off);
2219
2220 ifp = m->m_pkthdr.rcvif;
2221 redtgt6 = nd_rd->nd_rd_target;
2222 reddst6 = nd_rd->nd_rd_dst;
2223
2224 if (in6_setscope(&redtgt6, ifp, NULL) ||
2225 in6_setscope(&reddst6, ifp, NULL)) {
2226 goto freeit;
2227 }
2228
2229 /* validation */
2230 src6 = ip6->ip6_src;
2231 if (!IN6_IS_ADDR_LINKLOCAL(&src6)) {
2232 nd6log((LOG_ERR,
2233 "ICMP6 redirect sent from %s rejected; "
2234 "must be from linklocal\n",
2235 ip6_sprintf(ip6buf, &src6)));
2236 goto bad;
2237 }
2238 if (__predict_false(ip6->ip6_hlim != 255)) {
2239 ICMP6STAT_INC(icp6s_invlhlim);
2240 nd6log((LOG_ERR,
2241 "ICMP6 redirect sent from %s rejected; "
2242 "hlim=%d (must be 255)\n",
2243 ip6_sprintf(ip6buf, &src6), ip6->ip6_hlim));
2244 goto bad;
2245 }
2246 {
2247 /* ip6->ip6_src must be equal to gw for icmp6->icmp6_reddst */
2248 struct nhop_object *nh;
2249 struct in6_addr kdst;
2250 uint32_t scopeid;
2251
2252 in6_splitscope(&reddst6, &kdst, &scopeid);
2253 NET_EPOCH_ASSERT();
2254 nh = fib6_lookup(ifp->if_fib, &kdst, scopeid, 0, 0);
2255 if (nh != NULL) {
2256 struct in6_addr nh_addr;
2257 nh_addr = ifatoia6(nh->nh_ifa)->ia_addr.sin6_addr;
2258 if ((nh->nh_flags & NHF_GATEWAY) == 0) {
2259 nd6log((LOG_ERR,
2260 "ICMP6 redirect rejected; no route "
2261 "with inet6 gateway found for redirect dst: %s\n",
2262 icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2263 goto bad;
2264 }
2265
2266 /*
2267 * Embed scope zone id into next hop address.
2268 */
2269 nh_addr = nh->gw6_sa.sin6_addr;
2270
2271 if (IN6_ARE_ADDR_EQUAL(&src6, &nh_addr) == 0) {
2272 nd6log((LOG_ERR,
2273 "ICMP6 redirect rejected; "
2274 "not equal to gw-for-src=%s (must be same): "
2275 "%s\n",
2276 ip6_sprintf(ip6buf, &nh_addr),
2277 icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2278 goto bad;
2279 }
2280 } else {
2281 nd6log((LOG_ERR,
2282 "ICMP6 redirect rejected; "
2283 "no route found for redirect dst: %s\n",
2284 icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2285 goto bad;
2286 }
2287 }
2288 if (IN6_IS_ADDR_MULTICAST(&reddst6)) {
2289 nd6log((LOG_ERR,
2290 "ICMP6 redirect rejected; "
2291 "redirect dst must be unicast: %s\n",
2292 icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2293 goto bad;
2294 }
2295
2296 is_router = is_onlink = 0;
2297 if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
2298 is_router = 1; /* router case */
2299 if (bcmp(&redtgt6, &reddst6, sizeof(redtgt6)) == 0)
2300 is_onlink = 1; /* on-link destination case */
2301 if (!is_router && !is_onlink) {
2302 nd6log((LOG_ERR,
2303 "ICMP6 redirect rejected; "
2304 "neither router case nor onlink case: %s\n",
2305 icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2306 goto bad;
2307 }
2308
2309 icmp6len -= sizeof(*nd_rd);
2310 nd6_option_init(nd_rd + 1, icmp6len, &ndopts);
2311 if (nd6_options(&ndopts) < 0) {
2312 nd6log((LOG_INFO, "%s: invalid ND option, rejected: %s\n",
2313 __func__, icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2314 /* nd6_options have incremented stats */
2315 goto freeit;
2316 }
2317
2318 lladdr = NULL;
2319 lladdrlen = 0;
2320 if (ndopts.nd_opts_tgt_lladdr) {
2321 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
2322 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
2323 }
2324
2325 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
2326 nd6log((LOG_INFO, "%s: lladdrlen mismatch for %s "
2327 "(if %d, icmp6 packet %d): %s\n",
2328 __func__, ip6_sprintf(ip6buf, &redtgt6),
2329 ifp->if_addrlen, lladdrlen - 2,
2330 icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2331 goto bad;
2332 }
2333
2334 /* Validation passed. */
2335
2336 /* RFC 2461 8.3 */
2337 nd6_cache_lladdr(ifp, &redtgt6, lladdr, lladdrlen, ND_REDIRECT,
2338 is_onlink ? ND_REDIRECT_ONLINK : ND_REDIRECT_ROUTER);
2339
2340 /*
2341 * Install a gateway route in the better-router case or an interface
2342 * route in the on-link-destination case.
2343 */
2344 {
2345 struct sockaddr_in6 sdst;
2346 struct sockaddr_in6 sgw;
2347 struct sockaddr_in6 ssrc;
2348 struct sockaddr *gw;
2349 int rt_flags;
2350 u_int fibnum;
2351
2352 bzero(&sdst, sizeof(sdst));
2353 bzero(&ssrc, sizeof(ssrc));
2354 sdst.sin6_family = ssrc.sin6_family = AF_INET6;
2355 sdst.sin6_len = ssrc.sin6_len = sizeof(struct sockaddr_in6);
2356 bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
2357 bcopy(&src6, &ssrc.sin6_addr, sizeof(struct in6_addr));
2358 rt_flags = 0;
2359 if (is_router) {
2360 bzero(&sgw, sizeof(sgw));
2361 sgw.sin6_family = AF_INET6;
2362 sgw.sin6_len = sizeof(struct sockaddr_in6);
2363 bcopy(&redtgt6, &sgw.sin6_addr,
2364 sizeof(struct in6_addr));
2365 gw = (struct sockaddr *)&sgw;
2366 rt_flags |= RTF_GATEWAY;
2367 } else
2368 gw = ifp->if_addr->ifa_addr;
2369 for (fibnum = 0; fibnum < rt_numfibs; fibnum++)
2370 rib_add_redirect(fibnum, (struct sockaddr *)&sdst, gw,
2371 (struct sockaddr *)&ssrc, ifp, rt_flags,
2372 V_icmp6_redirtimeout);
2373 }
2374
2375 freeit:
2376 m_freem(m);
2377 return;
2378
2379 bad:
2380 ICMP6STAT_INC(icp6s_badredirect);
2381 m_freem(m);
2382 }
2383
2384 void
icmp6_redirect_output(struct mbuf * m0,struct nhop_object * nh)2385 icmp6_redirect_output(struct mbuf *m0, struct nhop_object *nh)
2386 {
2387 struct ifnet *ifp; /* my outgoing interface */
2388 struct in6_addr *ifp_ll6;
2389 struct in6_addr *router_ll6;
2390 struct ip6_hdr *sip6; /* m0 as struct ip6_hdr */
2391 struct mbuf *m = NULL; /* newly allocated one */
2392 struct m_tag *mtag;
2393 struct ip6_hdr *ip6; /* m as struct ip6_hdr */
2394 struct nd_redirect *nd_rd;
2395 struct llentry *ln = NULL;
2396 size_t maxlen;
2397 u_char *p;
2398 struct ifnet *outif = NULL;
2399 struct sockaddr_in6 src_sa;
2400
2401 icmp6_errcount(ND_REDIRECT, 0);
2402
2403 /* if we are not router, we don't send icmp6 redirect */
2404 if (!V_ip6_forwarding)
2405 goto fail;
2406
2407 /* sanity check */
2408 if (!m0 || !nh || !(NH_IS_VALID(nh)) || !(ifp = nh->nh_ifp))
2409 goto fail;
2410
2411 /*
2412 * Address check:
2413 * the source address must identify a neighbor, and
2414 * the destination address must not be a multicast address
2415 * [RFC 2461, sec 8.2]
2416 */
2417 sip6 = mtod(m0, struct ip6_hdr *);
2418 bzero(&src_sa, sizeof(src_sa));
2419 src_sa.sin6_family = AF_INET6;
2420 src_sa.sin6_len = sizeof(src_sa);
2421 src_sa.sin6_addr = sip6->ip6_src;
2422 if (nd6_is_addr_neighbor(&src_sa, ifp) == 0)
2423 goto fail;
2424 if (IN6_IS_ADDR_MULTICAST(&sip6->ip6_dst))
2425 goto fail; /* what should we do here? */
2426
2427 /* rate limit */
2428 if (icmp6_ratelimit(&sip6->ip6_src, ND_REDIRECT, 0))
2429 goto fail;
2430
2431 /*
2432 * Since we are going to append up to 1280 bytes (= IPV6_MMTU),
2433 * we almost always ask for an mbuf cluster for simplicity.
2434 * (MHLEN < IPV6_MMTU is almost always true)
2435 */
2436 #if IPV6_MMTU >= MCLBYTES
2437 # error assumption failed about IPV6_MMTU and MCLBYTES
2438 #endif
2439 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
2440 if (m == NULL)
2441 goto fail;
2442 M_SETFIB(m, M_GETFIB(m0));
2443 maxlen = M_TRAILINGSPACE(m);
2444 maxlen = min(IPV6_MMTU, maxlen);
2445 /* just for safety */
2446 if (maxlen < sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) +
2447 ((sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7)) {
2448 goto fail;
2449 }
2450
2451 {
2452 /* get ip6 linklocal address for ifp(my outgoing interface). */
2453 struct in6_ifaddr *ia;
2454 if ((ia = in6ifa_ifpforlinklocal(ifp,
2455 IN6_IFF_NOTREADY|
2456 IN6_IFF_ANYCAST)) == NULL)
2457 goto fail;
2458 ifp_ll6 = &ia->ia_addr.sin6_addr;
2459 /* XXXRW: reference released prematurely. */
2460 ifa_free(&ia->ia_ifa);
2461 }
2462
2463 /* get ip6 linklocal address for the router. */
2464 if (nh->nh_flags & NHF_GATEWAY) {
2465 struct sockaddr_in6 *sin6;
2466 sin6 = &nh->gw6_sa;
2467 router_ll6 = &sin6->sin6_addr;
2468 if (!IN6_IS_ADDR_LINKLOCAL(router_ll6))
2469 router_ll6 = (struct in6_addr *)NULL;
2470 } else
2471 router_ll6 = (struct in6_addr *)NULL;
2472
2473 /* ip6 */
2474 ip6 = mtod(m, struct ip6_hdr *);
2475 ip6->ip6_flow = 0;
2476 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
2477 ip6->ip6_vfc |= IPV6_VERSION;
2478 /* ip6->ip6_plen will be set later */
2479 ip6->ip6_nxt = IPPROTO_ICMPV6;
2480 ip6->ip6_hlim = 255;
2481 /* ip6->ip6_src must be linklocal addr for my outgoing if. */
2482 bcopy(ifp_ll6, &ip6->ip6_src, sizeof(struct in6_addr));
2483 bcopy(&sip6->ip6_src, &ip6->ip6_dst, sizeof(struct in6_addr));
2484
2485 /* ND Redirect */
2486 nd_rd = (struct nd_redirect *)(ip6 + 1);
2487 nd_rd->nd_rd_type = ND_REDIRECT;
2488 nd_rd->nd_rd_code = 0;
2489 nd_rd->nd_rd_reserved = 0;
2490 if (nh->nh_flags & NHF_GATEWAY) {
2491 /*
2492 * nd_rd->nd_rd_target must be a link-local address in
2493 * better router cases.
2494 */
2495 if (!router_ll6)
2496 goto fail;
2497 bcopy(router_ll6, &nd_rd->nd_rd_target,
2498 sizeof(nd_rd->nd_rd_target));
2499 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
2500 sizeof(nd_rd->nd_rd_dst));
2501 } else {
2502 /* make sure redtgt == reddst */
2503 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_target,
2504 sizeof(nd_rd->nd_rd_target));
2505 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
2506 sizeof(nd_rd->nd_rd_dst));
2507 }
2508
2509 p = (u_char *)(nd_rd + 1);
2510
2511 if (!router_ll6)
2512 goto nolladdropt;
2513
2514 {
2515 /* target lladdr option */
2516 int len;
2517 struct nd_opt_hdr *nd_opt;
2518 char *lladdr;
2519
2520 ln = nd6_lookup(router_ll6, LLE_SF(AF_INET6, 0), ifp);
2521 if (ln == NULL)
2522 goto nolladdropt;
2523
2524 len = sizeof(*nd_opt) + ifp->if_addrlen;
2525 len = (len + 7) & ~7; /* round by 8 */
2526 /* safety check */
2527 if (len + (p - (u_char *)ip6) > maxlen)
2528 goto nolladdropt;
2529
2530 if (ln->la_flags & LLE_VALID) {
2531 nd_opt = (struct nd_opt_hdr *)p;
2532 nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
2533 nd_opt->nd_opt_len = len >> 3;
2534 lladdr = (char *)(nd_opt + 1);
2535 bcopy(ln->ll_addr, lladdr, ifp->if_addrlen);
2536 p += len;
2537 }
2538 }
2539 nolladdropt:
2540 if (ln != NULL)
2541 LLE_RUNLOCK(ln);
2542
2543 m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
2544
2545 /* just to be safe */
2546 #ifdef M_DECRYPTED /*not openbsd*/
2547 if (m0->m_flags & M_DECRYPTED)
2548 goto noredhdropt;
2549 #endif
2550 if (p - (u_char *)ip6 > maxlen)
2551 goto noredhdropt;
2552
2553 {
2554 /* redirected header option */
2555 int len;
2556 struct nd_opt_rd_hdr *nd_opt_rh;
2557
2558 /*
2559 * compute the maximum size for icmp6 redirect header option.
2560 * XXX room for auth header?
2561 */
2562 len = maxlen - (p - (u_char *)ip6);
2563 len &= ~7;
2564
2565 /* This is just for simplicity. */
2566 if (m0->m_pkthdr.len != m0->m_len) {
2567 if (m0->m_next) {
2568 m_freem(m0->m_next);
2569 m0->m_next = NULL;
2570 }
2571 m0->m_pkthdr.len = m0->m_len;
2572 }
2573
2574 /*
2575 * Redirected header option spec (RFC2461 4.6.3) talks nothing
2576 * about padding/truncate rule for the original IP packet.
2577 * From the discussion on IPv6imp in Feb 1999,
2578 * the consensus was:
2579 * - "attach as much as possible" is the goal
2580 * - pad if not aligned (original size can be guessed by
2581 * original ip6 header)
2582 * Following code adds the padding if it is simple enough,
2583 * and truncates if not.
2584 */
2585 if (m0->m_next || m0->m_pkthdr.len != m0->m_len)
2586 panic("assumption failed in %s:%d", __FILE__,
2587 __LINE__);
2588
2589 if (len - sizeof(*nd_opt_rh) < m0->m_pkthdr.len) {
2590 /* not enough room, truncate */
2591 m0->m_pkthdr.len = m0->m_len = len -
2592 sizeof(*nd_opt_rh);
2593 } else {
2594 /* enough room, pad or truncate */
2595 size_t extra;
2596
2597 extra = m0->m_pkthdr.len % 8;
2598 if (extra) {
2599 /* pad if easy enough, truncate if not */
2600 if (8 - extra <= M_TRAILINGSPACE(m0)) {
2601 /* pad */
2602 m0->m_len += (8 - extra);
2603 m0->m_pkthdr.len += (8 - extra);
2604 } else {
2605 /* truncate */
2606 m0->m_pkthdr.len -= extra;
2607 m0->m_len -= extra;
2608 }
2609 }
2610 len = m0->m_pkthdr.len + sizeof(*nd_opt_rh);
2611 m0->m_pkthdr.len = m0->m_len = len -
2612 sizeof(*nd_opt_rh);
2613 }
2614
2615 nd_opt_rh = (struct nd_opt_rd_hdr *)p;
2616 bzero(nd_opt_rh, sizeof(*nd_opt_rh));
2617 nd_opt_rh->nd_opt_rh_type = ND_OPT_REDIRECTED_HEADER;
2618 nd_opt_rh->nd_opt_rh_len = len >> 3;
2619 p += sizeof(*nd_opt_rh);
2620 m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
2621
2622 /* connect m0 to m */
2623 m_tag_delete_chain(m0, NULL);
2624 m0->m_flags &= ~M_PKTHDR;
2625 m->m_next = m0;
2626 m->m_pkthdr.len = m->m_len + m0->m_len;
2627 m0 = NULL;
2628 }
2629 noredhdropt:;
2630 if (m0) {
2631 m_freem(m0);
2632 m0 = NULL;
2633 }
2634
2635 /* XXX: clear embedded link IDs in the inner header */
2636 in6_clearscope(&sip6->ip6_src);
2637 in6_clearscope(&sip6->ip6_dst);
2638 in6_clearscope(&nd_rd->nd_rd_target);
2639 in6_clearscope(&nd_rd->nd_rd_dst);
2640
2641 ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
2642
2643 nd_rd->nd_rd_cksum = 0;
2644 nd_rd->nd_rd_cksum = in6_cksum(m, IPPROTO_ICMPV6,
2645 sizeof(*ip6), ntohs(ip6->ip6_plen));
2646
2647 if (send_sendso_input_hook != NULL) {
2648 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING, sizeof(unsigned short),
2649 M_NOWAIT);
2650 if (mtag == NULL)
2651 goto fail;
2652 *(unsigned short *)(mtag + 1) = nd_rd->nd_rd_type;
2653 m_tag_prepend(m, mtag);
2654 }
2655
2656 /* send the packet to outside... */
2657 ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
2658 if (outif) {
2659 icmp6_ifstat_inc(outif, ifs6_out_msg);
2660 icmp6_ifstat_inc(outif, ifs6_out_redirect);
2661 }
2662 ICMP6STAT_INC2(icp6s_outhist, ND_REDIRECT);
2663
2664 return;
2665
2666 fail:
2667 if (m)
2668 m_freem(m);
2669 if (m0)
2670 m_freem(m0);
2671 }
2672
2673 /*
2674 * ICMPv6 socket option processing.
2675 */
2676 int
icmp6_ctloutput(struct socket * so,struct sockopt * sopt)2677 icmp6_ctloutput(struct socket *so, struct sockopt *sopt)
2678 {
2679 int error = 0;
2680 int optlen;
2681 struct inpcb *inp = sotoinpcb(so);
2682 int level, op, optname;
2683
2684 if (sopt) {
2685 level = sopt->sopt_level;
2686 op = sopt->sopt_dir;
2687 optname = sopt->sopt_name;
2688 optlen = sopt->sopt_valsize;
2689 } else
2690 level = op = optname = optlen = 0;
2691
2692 if (level != IPPROTO_ICMPV6) {
2693 return EINVAL;
2694 }
2695
2696 switch (op) {
2697 case SOPT_SET:
2698 switch (optname) {
2699 case ICMP6_FILTER:
2700 {
2701 struct icmp6_filter ic6f;
2702
2703 if (optlen != sizeof(ic6f)) {
2704 error = EMSGSIZE;
2705 break;
2706 }
2707 error = sooptcopyin(sopt, &ic6f, optlen, optlen);
2708 if (error == 0) {
2709 INP_WLOCK(inp);
2710 *inp->in6p_icmp6filt = ic6f;
2711 INP_WUNLOCK(inp);
2712 }
2713 break;
2714 }
2715
2716 default:
2717 error = ENOPROTOOPT;
2718 break;
2719 }
2720 break;
2721
2722 case SOPT_GET:
2723 switch (optname) {
2724 case ICMP6_FILTER:
2725 {
2726 struct icmp6_filter ic6f;
2727
2728 INP_RLOCK(inp);
2729 ic6f = *inp->in6p_icmp6filt;
2730 INP_RUNLOCK(inp);
2731 error = sooptcopyout(sopt, &ic6f, sizeof(ic6f));
2732 break;
2733 }
2734
2735 default:
2736 error = ENOPROTOOPT;
2737 break;
2738 }
2739 break;
2740 }
2741
2742 return (error);
2743 }
2744
2745 static int sysctl_icmp6lim_and_jitter(SYSCTL_HANDLER_ARGS);
2746 VNET_DEFINE_STATIC(u_int, icmp6errppslim) = 100;
2747 #define V_icmp6errppslim VNET(icmp6errppslim)
2748 SYSCTL_PROC(_net_inet6_icmp6, ICMPV6CTL_ERRPPSLIMIT, errppslimit,
2749 CTLTYPE_UINT | CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6errppslim), 0,
2750 &sysctl_icmp6lim_and_jitter, "IU",
2751 "Maximum number of ICMPv6 error/reply messages per second");
2752
2753 VNET_DEFINE_STATIC(int, icmp6lim_curr_jitter) = 0;
2754 #define V_icmp6lim_curr_jitter VNET(icmp6lim_curr_jitter)
2755
2756 VNET_DEFINE_STATIC(u_int, icmp6lim_jitter) = 8;
2757 #define V_icmp6lim_jitter VNET(icmp6lim_jitter)
2758 SYSCTL_PROC(_net_inet6_icmp6, OID_AUTO, icmp6lim_jitter, CTLTYPE_UINT |
2759 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6lim_jitter), 0,
2760 &sysctl_icmp6lim_and_jitter, "IU",
2761 "Random errppslimit jitter adjustment limit");
2762
2763 VNET_DEFINE_STATIC(int, icmp6lim_output) = 1;
2764 #define V_icmp6lim_output VNET(icmp6lim_output)
2765 SYSCTL_INT(_net_inet6_icmp6, OID_AUTO, icmp6lim_output,
2766 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6lim_output), 0,
2767 "Enable logging of ICMPv6 response rate limiting");
2768
2769 typedef enum {
2770 RATELIM_PARAM_PROB = 0,
2771 RATELIM_TOO_BIG,
2772 RATELIM_UNREACH,
2773 RATELIM_TEXCEED,
2774 RATELIM_REDIR,
2775 RATELIM_REPLY,
2776 RATELIM_OTHER,
2777 RATELIM_MAX
2778 } ratelim_which;
2779
2780 static const char *icmp6_rate_descrs[RATELIM_MAX] = {
2781 [RATELIM_PARAM_PROB] = "bad IPv6 header",
2782 [RATELIM_TOO_BIG] = "packet too big",
2783 [RATELIM_UNREACH] = "destination unreachable",
2784 [RATELIM_TEXCEED] = "time exceeded",
2785 [RATELIM_REPLY] = "echo reply",
2786 [RATELIM_REDIR] = "neighbor discovery redirect",
2787 [RATELIM_OTHER] = "(other)",
2788 };
2789
2790 static void
icmp6lim_new_jitter(void)2791 icmp6lim_new_jitter(void)
2792 {
2793 /*
2794 * Adjust limit +/- to jitter the measurement to deny a side-channel
2795 * port scan as in https://dl.acm.org/doi/10.1145/3372297.3417280
2796 */
2797 if (V_icmp6lim_jitter > 0)
2798 V_icmp6lim_curr_jitter =
2799 arc4random_uniform(V_icmp6lim_jitter * 2 + 1) -
2800 V_icmp6lim_jitter;
2801 }
2802
2803 static int
sysctl_icmp6lim_and_jitter(SYSCTL_HANDLER_ARGS)2804 sysctl_icmp6lim_and_jitter(SYSCTL_HANDLER_ARGS)
2805 {
2806 uint32_t new;
2807 int error;
2808 bool lim;
2809
2810 MPASS(oidp->oid_arg1 == &VNET_NAME(icmp6errppslim) ||
2811 oidp->oid_arg1 == &VNET_NAME(icmp6lim_jitter));
2812
2813 lim = (oidp->oid_arg1 == &VNET_NAME(icmp6errppslim));
2814 new = lim ? V_icmp6errppslim : V_icmp6lim_jitter;
2815 error = sysctl_handle_int(oidp, &new, 0, req);
2816 if (error == 0 && req->newptr) {
2817 if (lim) {
2818 if (new != 0 && new <= V_icmp6lim_jitter)
2819 error = EINVAL;
2820 else
2821 V_icmp6errppslim = new;
2822 } else {
2823 if (new >= V_icmp6errppslim)
2824 error = EINVAL;
2825 else {
2826 V_icmp6lim_jitter = new;
2827 icmp6lim_new_jitter();
2828 }
2829 }
2830 }
2831 MPASS(V_icmp6errppslim == 0 || V_icmp6errppslim > V_icmp6lim_jitter);
2832
2833 return (error);
2834 }
2835
2836
2837 VNET_DEFINE_STATIC(struct counter_rate, icmp6_rates[RATELIM_MAX]);
2838 #define V_icmp6_rates VNET(icmp6_rates)
2839
2840 static void
icmp6_ratelimit_init(void)2841 icmp6_ratelimit_init(void)
2842 {
2843
2844 for (int i = 0; i < RATELIM_MAX; i++) {
2845 V_icmp6_rates[i].cr_rate = counter_u64_alloc(M_WAITOK);
2846 V_icmp6_rates[i].cr_ticks = ticks;
2847 }
2848 icmp6lim_new_jitter();
2849 }
2850 VNET_SYSINIT(icmp6_ratelimit, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY,
2851 icmp6_ratelimit_init, NULL);
2852
2853 #ifdef VIMAGE
2854 static void
icmp6_ratelimit_uninit(void)2855 icmp6_ratelimit_uninit(void)
2856 {
2857
2858 for (int i = 0; i < RATELIM_MAX; i++)
2859 counter_u64_free(V_icmp6_rates[i].cr_rate);
2860 }
2861 VNET_SYSUNINIT(icmp6_ratelimit, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD,
2862 icmp6_ratelimit_uninit, NULL);
2863 #endif
2864
2865 /*
2866 * Perform rate limit check.
2867 * Returns 0 if it is okay to send the icmp6 packet.
2868 * Returns 1 if the router SHOULD NOT send this icmp6 packet due to rate
2869 * limitation.
2870 *
2871 * XXX per-destination/type check necessary?
2872 *
2873 * dst - not used at this moment
2874 * code - not used at this moment
2875 */
2876 int
icmp6_ratelimit(const struct in6_addr * dst,const int type,const int code)2877 icmp6_ratelimit(const struct in6_addr *dst, const int type, const int code)
2878 {
2879 ratelim_which which;
2880 int64_t pps;
2881
2882 if (V_icmp6errppslim == 0)
2883 return (0);
2884
2885 switch (type) {
2886 case ICMP6_PARAM_PROB:
2887 which = RATELIM_PARAM_PROB;
2888 break;
2889 case ICMP6_PACKET_TOO_BIG:
2890 which = RATELIM_TOO_BIG;
2891 break;
2892 case ICMP6_DST_UNREACH:
2893 which = RATELIM_UNREACH;
2894 break;
2895 case ICMP6_TIME_EXCEEDED:
2896 which = RATELIM_TEXCEED;
2897 break;
2898 case ND_REDIRECT:
2899 which = RATELIM_REDIR;
2900 break;
2901 case ICMP6_ECHO_REPLY:
2902 which = RATELIM_REPLY;
2903 break;
2904 default:
2905 which = RATELIM_OTHER;
2906 break;
2907 };
2908
2909 pps = counter_ratecheck(&V_icmp6_rates[which], V_icmp6errppslim +
2910 V_icmp6lim_curr_jitter);
2911 if (pps > 0) {
2912 if (V_icmp6lim_output)
2913 log(LOG_NOTICE, "Limiting ICMPv6 %s output from %jd "
2914 "to %d packets/sec\n", icmp6_rate_descrs[which],
2915 (intmax_t )pps, V_icmp6errppslim +
2916 V_icmp6lim_curr_jitter);
2917 icmp6lim_new_jitter();
2918 }
2919 if (pps == -1) {
2920 ICMP6STAT_INC(icp6s_toofreq);
2921 return (-1);
2922 }
2923
2924 return (0);
2925 }
2926