1 /*-
2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the project nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $KAME: nd6_nbr.c,v 1.86 2002/01/21 02:33:04 jinmei Exp $
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD: src/sys/netinet6/nd6_nbr.c,v 1.57 2008/12/02 21:37:28 bz Exp $");
34
35 #include "opt_inet.h"
36 #include "opt_inet6.h"
37 #include "opt_ipsec.h"
38 #include "opt_carp.h"
39 #include "opt_mpath.h"
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/malloc.h>
44 #include <sys/mbuf.h>
45 #include <sys/socket.h>
46 #include <sys/sockio.h>
47 #include <sys/time.h>
48 #include <sys/kernel.h>
49 #include <sys/errno.h>
50 #include <sys/syslog.h>
51 #include <sys/queue.h>
52 #include <sys/callout.h>
53 #include <sys/vimage.h>
54
55 #include <net/if.h>
56 #include <net/if_types.h>
57 #include <net/if_dl.h>
58 #include <net/if_var.h>
59 #include <net/route.h>
60 #ifdef RADIX_MPATH
61 #include <net/radix_mpath.h>
62 #endif
63
64 #include <netinet/in.h>
65 #include <netinet/in_var.h>
66 #include <netinet6/in6_var.h>
67 #include <netinet6/in6_ifattach.h>
68 #include <netinet/ip6.h>
69 #include <netinet6/ip6_var.h>
70 #include <netinet6/scope6_var.h>
71 #include <netinet6/nd6.h>
72 #include <netinet/icmp6.h>
73 #include <netinet6/vinet6.h>
74
75 #ifdef DEV_CARP
76 #include <netinet/ip_carp.h>
77 #endif
78
79 #define SDL(s) ((struct sockaddr_dl *)s)
80
81 struct dadq;
82 static struct dadq *nd6_dad_find(struct ifaddr *);
83 static void nd6_dad_starttimer(struct dadq *, int);
84 static void nd6_dad_stoptimer(struct dadq *);
85 static void nd6_dad_timer(struct ifaddr *);
86 static void nd6_dad_ns_output(struct dadq *, struct ifaddr *);
87 static void nd6_dad_ns_input(struct ifaddr *);
88 static void nd6_dad_na_input(struct ifaddr *);
89
90 #ifdef VIMAGE_GLOBALS
91 int dad_ignore_ns;
92 int dad_maxtry;
93 #endif
94
95 /*
96 * Input a Neighbor Solicitation Message.
97 *
98 * Based on RFC 2461
99 * Based on RFC 2462 (duplicate address detection)
100 */
101 void
102 nd6_ns_input(struct mbuf *m, int off, int icmp6len)
103 {
104 INIT_VNET_INET6(curvnet);
105 struct ifnet *ifp = m->m_pkthdr.rcvif;
106 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
107 struct nd_neighbor_solicit *nd_ns;
108 struct in6_addr saddr6 = ip6->ip6_src;
109 struct in6_addr daddr6 = ip6->ip6_dst;
110 struct in6_addr taddr6;
111 struct in6_addr myaddr6;
112 char *lladdr = NULL;
113 struct ifaddr *ifa = NULL;
114 int lladdrlen = 0;
115 int anycast = 0, proxy = 0, tentative = 0;
116 int tlladdr;
117 union nd_opts ndopts;
118 struct sockaddr_dl *proxydl = NULL;
119 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
120
121 #ifndef PULLDOWN_TEST
122 IP6_EXTHDR_CHECK(m, off, icmp6len,);
123 nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
124 #else
125 IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
126 if (nd_ns == NULL) {
127 V_icmp6stat.icp6s_tooshort++;
128 return;
129 }
130 #endif
131 ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
132 taddr6 = nd_ns->nd_ns_target;
133 if (in6_setscope(&taddr6, ifp, NULL) != 0)
134 goto bad;
135
136 if (ip6->ip6_hlim != 255) {
137 nd6log((LOG_ERR,
138 "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
139 ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
140 ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
141 goto bad;
142 }
143
144 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
145 /* dst has to be a solicited node multicast address. */
146 if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL &&
147 /* don't check ifindex portion */
148 daddr6.s6_addr32[1] == 0 &&
149 daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE &&
150 daddr6.s6_addr8[12] == 0xff) {
151 ; /* good */
152 } else {
153 nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
154 "(wrong ip6 dst)\n"));
155 goto bad;
156 }
157 } else if (!V_nd6_onlink_ns_rfc4861) {
158 struct sockaddr_in6 src_sa6;
159
160 /*
161 * According to recent IETF discussions, it is not a good idea
162 * to accept a NS from an address which would not be deemed
163 * to be a neighbor otherwise. This point is expected to be
164 * clarified in future revisions of the specification.
165 */
166 bzero(&src_sa6, sizeof(src_sa6));
167 src_sa6.sin6_family = AF_INET6;
168 src_sa6.sin6_len = sizeof(src_sa6);
169 src_sa6.sin6_addr = saddr6;
170 if (!nd6_is_addr_neighbor(&src_sa6, ifp)) {
171 nd6log((LOG_INFO, "nd6_ns_input: "
172 "NS packet from non-neighbor\n"));
173 goto bad;
174 }
175 }
176
177 if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
178 nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
179 goto bad;
180 }
181
182 icmp6len -= sizeof(*nd_ns);
183 nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
184 if (nd6_options(&ndopts) < 0) {
185 nd6log((LOG_INFO,
186 "nd6_ns_input: invalid ND option, ignored\n"));
187 /* nd6_options have incremented stats */
188 goto freeit;
189 }
190
191 if (ndopts.nd_opts_src_lladdr) {
192 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
193 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
194 }
195
196 if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
197 nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
198 "(link-layer address option)\n"));
199 goto bad;
200 }
201
202 /*
203 * Attaching target link-layer address to the NA?
204 * (RFC 2461 7.2.4)
205 *
206 * NS IP dst is unicast/anycast MUST NOT add
207 * NS IP dst is solicited-node multicast MUST add
208 *
209 * In implementation, we add target link-layer address by default.
210 * We do not add one in MUST NOT cases.
211 */
212 if (!IN6_IS_ADDR_MULTICAST(&daddr6))
213 tlladdr = 0;
214 else
215 tlladdr = 1;
216
217 /*
218 * Target address (taddr6) must be either:
219 * (1) Valid unicast/anycast address for my receiving interface,
220 * (2) Unicast address for which I'm offering proxy service, or
221 * (3) "tentative" address on which DAD is being performed.
222 */
223 /* (1) and (3) check. */
224 #ifdef DEV_CARP
225 if (ifp->if_carp)
226 ifa = carp_iamatch6(ifp->if_carp, &taddr6);
227 if (ifa == NULL)
228 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
229 #else
230 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
231 #endif
232
233 /* (2) check. */
234 if (ifa == NULL) {
235 struct rtentry *rt;
236 struct sockaddr_in6 tsin6;
237 int need_proxy;
238 #ifdef RADIX_MPATH
239 struct route_in6 ro;
240 #endif
241
242 bzero(&tsin6, sizeof tsin6);
243 tsin6.sin6_len = sizeof(struct sockaddr_in6);
244 tsin6.sin6_family = AF_INET6;
245 tsin6.sin6_addr = taddr6;
246
247 #ifdef RADIX_MPATH
248 bzero(&ro, sizeof(ro));
249 ro.ro_dst = tsin6;
250 rtalloc_mpath((struct route *)&ro, RTF_ANNOUNCE);
251 rt = ro.ro_rt;
252 #else
253 rt = rtalloc1((struct sockaddr *)&tsin6, 0, 0);
254 #endif
255 need_proxy = (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 &&
256 rt->rt_gateway->sa_family == AF_LINK);
257 if (rt)
258 rtfree(rt);
259 if (need_proxy) {
260 /*
261 * proxy NDP for single entry
262 */
263 ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
264 IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
265 if (ifa) {
266 proxy = 1;
267 proxydl = SDL(rt->rt_gateway);
268 }
269 }
270 }
271 if (ifa == NULL) {
272 /*
273 * We've got an NS packet, and we don't have that adddress
274 * assigned for us. We MUST silently ignore it.
275 * See RFC2461 7.2.3.
276 */
277 goto freeit;
278 }
279 myaddr6 = *IFA_IN6(ifa);
280 anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
281 tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
282 if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
283 goto freeit;
284
285 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
286 nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
287 "(if %d, NS packet %d)\n",
288 ip6_sprintf(ip6bufs, &taddr6),
289 ifp->if_addrlen, lladdrlen - 2));
290 goto bad;
291 }
292
293 if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
294 nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
295 ip6_sprintf(ip6bufs, &saddr6)));
296 goto freeit;
297 }
298
299 /*
300 * We have neighbor solicitation packet, with target address equals to
301 * one of my tentative address.
302 *
303 * src addr how to process?
304 * --- ---
305 * multicast of course, invalid (rejected in ip6_input)
306 * unicast somebody is doing address resolution -> ignore
307 * unspec dup address detection
308 *
309 * The processing is defined in RFC 2462.
310 */
311 if (tentative) {
312 /*
313 * If source address is unspecified address, it is for
314 * duplicate address detection.
315 *
316 * If not, the packet is for addess resolution;
317 * silently ignore it.
318 */
319 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
320 nd6_dad_ns_input(ifa);
321
322 goto freeit;
323 }
324
325 /*
326 * If the source address is unspecified address, entries must not
327 * be created or updated.
328 * It looks that sender is performing DAD. Output NA toward
329 * all-node multicast address, to tell the sender that I'm using
330 * the address.
331 * S bit ("solicited") must be zero.
332 */
333 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
334 struct in6_addr in6_all;
335
336 in6_all = in6addr_linklocal_allnodes;
337 if (in6_setscope(&in6_all, ifp, NULL) != 0)
338 goto bad;
339 nd6_na_output(ifp, &in6_all, &taddr6,
340 ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
341 (V_ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
342 tlladdr, (struct sockaddr *)proxydl);
343 goto freeit;
344 }
345
346 nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen,
347 ND_NEIGHBOR_SOLICIT, 0);
348
349 nd6_na_output(ifp, &saddr6, &taddr6,
350 ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
351 (V_ip6_forwarding ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED,
352 tlladdr, (struct sockaddr *)proxydl);
353 freeit:
354 m_freem(m);
355 return;
356
357 bad:
358 nd6log((LOG_ERR, "nd6_ns_input: src=%s\n",
359 ip6_sprintf(ip6bufs, &saddr6)));
360 nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n",
361 ip6_sprintf(ip6bufs, &daddr6)));
362 nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n",
363 ip6_sprintf(ip6bufs, &taddr6)));
364 V_icmp6stat.icp6s_badns++;
365 m_freem(m);
366 }
367
368 /*
369 * Output a Neighbor Solicitation Message. Caller specifies:
370 * - ICMP6 header source IP6 address
371 * - ND6 header target IP6 address
372 * - ND6 header source datalink address
373 *
374 * Based on RFC 2461
375 * Based on RFC 2462 (duplicate address detection)
376 *
377 * ln - for source address determination
378 * dad - duplicate address detection
379 */
380 void
381 nd6_ns_output(struct ifnet *ifp, const struct in6_addr *daddr6,
382 const struct in6_addr *taddr6, struct llinfo_nd6 *ln, int dad)
383 {
384 INIT_VNET_INET6(ifp->if_vnet);
385 struct mbuf *m;
386 struct ip6_hdr *ip6;
387 struct nd_neighbor_solicit *nd_ns;
388 struct in6_addr *src, src_in;
389 struct ip6_moptions im6o;
390 int icmp6len;
391 int maxlen;
392 caddr_t mac;
393 struct route_in6 ro;
394
395 bzero(&ro, sizeof(ro));
396
397 if (IN6_IS_ADDR_MULTICAST(taddr6))
398 return;
399
400 /* estimate the size of message */
401 maxlen = sizeof(*ip6) + sizeof(*nd_ns);
402 maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
403 if (max_linkhdr + maxlen >= MCLBYTES) {
404 #ifdef DIAGNOSTIC
405 printf("nd6_ns_output: max_linkhdr + maxlen >= MCLBYTES "
406 "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
407 #endif
408 return;
409 }
410
411 MGETHDR(m, M_DONTWAIT, MT_DATA);
412 if (m && max_linkhdr + maxlen >= MHLEN) {
413 MCLGET(m, M_DONTWAIT);
414 if ((m->m_flags & M_EXT) == 0) {
415 m_free(m);
416 m = NULL;
417 }
418 }
419 if (m == NULL)
420 return;
421 m->m_pkthdr.rcvif = NULL;
422
423 if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
424 m->m_flags |= M_MCAST;
425 im6o.im6o_multicast_ifp = ifp;
426 im6o.im6o_multicast_hlim = 255;
427 im6o.im6o_multicast_loop = 0;
428 }
429
430 icmp6len = sizeof(*nd_ns);
431 m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
432 m->m_data += max_linkhdr; /* or MH_ALIGN() equivalent? */
433
434 /* fill neighbor solicitation packet */
435 ip6 = mtod(m, struct ip6_hdr *);
436 ip6->ip6_flow = 0;
437 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
438 ip6->ip6_vfc |= IPV6_VERSION;
439 /* ip6->ip6_plen will be set later */
440 ip6->ip6_nxt = IPPROTO_ICMPV6;
441 ip6->ip6_hlim = 255;
442 if (daddr6)
443 ip6->ip6_dst = *daddr6;
444 else {
445 ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
446 ip6->ip6_dst.s6_addr16[1] = 0;
447 ip6->ip6_dst.s6_addr32[1] = 0;
448 ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
449 ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
450 ip6->ip6_dst.s6_addr8[12] = 0xff;
451 if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
452 goto bad;
453 }
454 if (!dad) {
455 /*
456 * RFC2461 7.2.2:
457 * "If the source address of the packet prompting the
458 * solicitation is the same as one of the addresses assigned
459 * to the outgoing interface, that address SHOULD be placed
460 * in the IP Source Address of the outgoing solicitation.
461 * Otherwise, any one of the addresses assigned to the
462 * interface should be used."
463 *
464 * We use the source address for the prompting packet
465 * (saddr6), if:
466 * - saddr6 is given from the caller (by giving "ln"), and
467 * - saddr6 belongs to the outgoing interface.
468 * Otherwise, we perform the source address selection as usual.
469 */
470 struct ip6_hdr *hip6; /* hold ip6 */
471 struct in6_addr *hsrc = NULL;
472
473 if (ln && ln->ln_hold) {
474 /*
475 * assuming every packet in ln_hold has the same IP
476 * header
477 */
478 hip6 = mtod(ln->ln_hold, struct ip6_hdr *);
479 /* XXX pullup? */
480 if (sizeof(*hip6) < ln->ln_hold->m_len)
481 hsrc = &hip6->ip6_src;
482 else
483 hsrc = NULL;
484 }
485 if (hsrc && in6ifa_ifpwithaddr(ifp, hsrc))
486 src = hsrc;
487 else {
488 int error;
489 struct sockaddr_in6 dst_sa;
490
491 bzero(&dst_sa, sizeof(dst_sa));
492 dst_sa.sin6_family = AF_INET6;
493 dst_sa.sin6_len = sizeof(dst_sa);
494 dst_sa.sin6_addr = ip6->ip6_dst;
495
496 src = in6_selectsrc(&dst_sa, NULL,
497 NULL, &ro, NULL, NULL, &error);
498 if (src == NULL) {
499 char ip6buf[INET6_ADDRSTRLEN];
500 nd6log((LOG_DEBUG,
501 "nd6_ns_output: source can't be "
502 "determined: dst=%s, error=%d\n",
503 ip6_sprintf(ip6buf, &dst_sa.sin6_addr),
504 error));
505 goto bad;
506 }
507 }
508 } else {
509 /*
510 * Source address for DAD packet must always be IPv6
511 * unspecified address. (0::0)
512 * We actually don't have to 0-clear the address (we did it
513 * above), but we do so here explicitly to make the intention
514 * clearer.
515 */
516 bzero(&src_in, sizeof(src_in));
517 src = &src_in;
518 }
519 ip6->ip6_src = *src;
520 nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1);
521 nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT;
522 nd_ns->nd_ns_code = 0;
523 nd_ns->nd_ns_reserved = 0;
524 nd_ns->nd_ns_target = *taddr6;
525 in6_clearscope(&nd_ns->nd_ns_target); /* XXX */
526
527 /*
528 * Add source link-layer address option.
529 *
530 * spec implementation
531 * --- ---
532 * DAD packet MUST NOT do not add the option
533 * there's no link layer address:
534 * impossible do not add the option
535 * there's link layer address:
536 * Multicast NS MUST add one add the option
537 * Unicast NS SHOULD add one add the option
538 */
539 if (!dad && (mac = nd6_ifptomac(ifp))) {
540 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
541 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
542 /* 8 byte alignments... */
543 optlen = (optlen + 7) & ~7;
544
545 m->m_pkthdr.len += optlen;
546 m->m_len += optlen;
547 icmp6len += optlen;
548 bzero((caddr_t)nd_opt, optlen);
549 nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
550 nd_opt->nd_opt_len = optlen >> 3;
551 bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
552 }
553
554 ip6->ip6_plen = htons((u_short)icmp6len);
555 nd_ns->nd_ns_cksum = 0;
556 nd_ns->nd_ns_cksum =
557 in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
558
559 ip6_output(m, NULL, &ro, dad ? IPV6_UNSPECSRC : 0, &im6o, NULL, NULL);
560 icmp6_ifstat_inc(ifp, ifs6_out_msg);
561 icmp6_ifstat_inc(ifp, ifs6_out_neighborsolicit);
562 V_icmp6stat.icp6s_outhist[ND_NEIGHBOR_SOLICIT]++;
563
564 if (ro.ro_rt) { /* we don't cache this route. */
565 RTFREE(ro.ro_rt);
566 }
567 return;
568
569 bad:
570 if (ro.ro_rt) {
571 RTFREE(ro.ro_rt);
572 }
573 m_freem(m);
574 return;
575 }
576
577 /*
578 * Neighbor advertisement input handling.
579 *
580 * Based on RFC 2461
581 * Based on RFC 2462 (duplicate address detection)
582 *
583 * the following items are not implemented yet:
584 * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
585 * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
586 */
587 void
588 nd6_na_input(struct mbuf *m, int off, int icmp6len)
589 {
590 INIT_VNET_INET6(curvnet);
591 struct ifnet *ifp = m->m_pkthdr.rcvif;
592 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
593 struct nd_neighbor_advert *nd_na;
594 struct in6_addr daddr6 = ip6->ip6_dst;
595 struct in6_addr taddr6;
596 int flags;
597 int is_router;
598 int is_solicited;
599 int is_override;
600 char *lladdr = NULL;
601 int lladdrlen = 0;
602 struct ifaddr *ifa;
603 struct llinfo_nd6 *ln;
604 struct rtentry *rt;
605 struct sockaddr_dl *sdl;
606 union nd_opts ndopts;
607 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
608
609 if (ip6->ip6_hlim != 255) {
610 nd6log((LOG_ERR,
611 "nd6_na_input: invalid hlim (%d) from %s to %s on %s\n",
612 ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
613 ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
614 goto bad;
615 }
616
617 #ifndef PULLDOWN_TEST
618 IP6_EXTHDR_CHECK(m, off, icmp6len,);
619 nd_na = (struct nd_neighbor_advert *)((caddr_t)ip6 + off);
620 #else
621 IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len);
622 if (nd_na == NULL) {
623 V_icmp6stat.icp6s_tooshort++;
624 return;
625 }
626 #endif
627
628 flags = nd_na->nd_na_flags_reserved;
629 is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
630 is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
631 is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
632
633 taddr6 = nd_na->nd_na_target;
634 if (in6_setscope(&taddr6, ifp, NULL))
635 goto bad; /* XXX: impossible */
636
637 if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
638 nd6log((LOG_ERR,
639 "nd6_na_input: invalid target address %s\n",
640 ip6_sprintf(ip6bufs, &taddr6)));
641 goto bad;
642 }
643 if (IN6_IS_ADDR_MULTICAST(&daddr6))
644 if (is_solicited) {
645 nd6log((LOG_ERR,
646 "nd6_na_input: a solicited adv is multicasted\n"));
647 goto bad;
648 }
649
650 icmp6len -= sizeof(*nd_na);
651 nd6_option_init(nd_na + 1, icmp6len, &ndopts);
652 if (nd6_options(&ndopts) < 0) {
653 nd6log((LOG_INFO,
654 "nd6_na_input: invalid ND option, ignored\n"));
655 /* nd6_options have incremented stats */
656 goto freeit;
657 }
658
659 if (ndopts.nd_opts_tgt_lladdr) {
660 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
661 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
662 }
663
664 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
665
666 /*
667 * Target address matches one of my interface address.
668 *
669 * If my address is tentative, this means that there's somebody
670 * already using the same address as mine. This indicates DAD failure.
671 * This is defined in RFC 2462.
672 *
673 * Otherwise, process as defined in RFC 2461.
674 */
675 if (ifa
676 && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
677 nd6_dad_na_input(ifa);
678 goto freeit;
679 }
680
681 /* Just for safety, maybe unnecessary. */
682 if (ifa) {
683 log(LOG_ERR,
684 "nd6_na_input: duplicate IP6 address %s\n",
685 ip6_sprintf(ip6bufs, &taddr6));
686 goto freeit;
687 }
688
689 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
690 nd6log((LOG_INFO, "nd6_na_input: lladdrlen mismatch for %s "
691 "(if %d, NA packet %d)\n", ip6_sprintf(ip6bufs, &taddr6),
692 ifp->if_addrlen, lladdrlen - 2));
693 goto bad;
694 }
695
696 /*
697 * If no neighbor cache entry is found, NA SHOULD silently be
698 * discarded.
699 */
700 rt = nd6_lookup(&taddr6, 0, ifp);
701 if ((rt == NULL) ||
702 ((ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) ||
703 ((sdl = SDL(rt->rt_gateway)) == NULL))
704 goto freeit;
705
706 if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
707 /*
708 * If the link-layer has address, and no lladdr option came,
709 * discard the packet.
710 */
711 if (ifp->if_addrlen && lladdr == NULL)
712 goto freeit;
713
714 /*
715 * Record link-layer address, and update the state.
716 */
717 sdl->sdl_alen = ifp->if_addrlen;
718 bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
719 if (is_solicited) {
720 ln->ln_state = ND6_LLINFO_REACHABLE;
721 ln->ln_byhint = 0;
722 if (!ND6_LLINFO_PERMANENT(ln)) {
723 nd6_llinfo_settimer(ln,
724 (long)ND_IFINFO(rt->rt_ifp)->reachable * hz);
725 }
726 } else {
727 ln->ln_state = ND6_LLINFO_STALE;
728 nd6_llinfo_settimer(ln, (long)V_nd6_gctimer * hz);
729 }
730 if ((ln->ln_router = is_router) != 0) {
731 /*
732 * This means a router's state has changed from
733 * non-reachable to probably reachable, and might
734 * affect the status of associated prefixes..
735 */
736 pfxlist_onlink_check();
737 }
738 } else {
739 int llchange;
740
741 /*
742 * Check if the link-layer address has changed or not.
743 */
744 if (lladdr == NULL)
745 llchange = 0;
746 else {
747 if (sdl->sdl_alen) {
748 if (bcmp(lladdr, LLADDR(sdl), ifp->if_addrlen))
749 llchange = 1;
750 else
751 llchange = 0;
752 } else
753 llchange = 1;
754 }
755
756 /*
757 * This is VERY complex. Look at it with care.
758 *
759 * override solicit lladdr llchange action
760 * (L: record lladdr)
761 *
762 * 0 0 n -- (2c)
763 * 0 0 y n (2b) L
764 * 0 0 y y (1) REACHABLE->STALE
765 * 0 1 n -- (2c) *->REACHABLE
766 * 0 1 y n (2b) L *->REACHABLE
767 * 0 1 y y (1) REACHABLE->STALE
768 * 1 0 n -- (2a)
769 * 1 0 y n (2a) L
770 * 1 0 y y (2a) L *->STALE
771 * 1 1 n -- (2a) *->REACHABLE
772 * 1 1 y n (2a) L *->REACHABLE
773 * 1 1 y y (2a) L *->REACHABLE
774 */
775 if (!is_override && (lladdr != NULL && llchange)) { /* (1) */
776 /*
777 * If state is REACHABLE, make it STALE.
778 * no other updates should be done.
779 */
780 if (ln->ln_state == ND6_LLINFO_REACHABLE) {
781 ln->ln_state = ND6_LLINFO_STALE;
782 nd6_llinfo_settimer(ln, (long)V_nd6_gctimer * hz);
783 }
784 goto freeit;
785 } else if (is_override /* (2a) */
786 || (!is_override && (lladdr != NULL && !llchange)) /* (2b) */
787 || lladdr == NULL) { /* (2c) */
788 /*
789 * Update link-local address, if any.
790 */
791 if (lladdr != NULL) {
792 sdl->sdl_alen = ifp->if_addrlen;
793 bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
794 }
795
796 /*
797 * If solicited, make the state REACHABLE.
798 * If not solicited and the link-layer address was
799 * changed, make it STALE.
800 */
801 if (is_solicited) {
802 ln->ln_state = ND6_LLINFO_REACHABLE;
803 ln->ln_byhint = 0;
804 if (!ND6_LLINFO_PERMANENT(ln)) {
805 nd6_llinfo_settimer(ln,
806 (long)ND_IFINFO(ifp)->reachable * hz);
807 }
808 } else {
809 if (lladdr != NULL && llchange) {
810 ln->ln_state = ND6_LLINFO_STALE;
811 nd6_llinfo_settimer(ln,
812 (long)V_nd6_gctimer * hz);
813 }
814 }
815 }
816
817 if (ln->ln_router && !is_router) {
818 /*
819 * The peer dropped the router flag.
820 * Remove the sender from the Default Router List and
821 * update the Destination Cache entries.
822 */
823 struct nd_defrouter *dr;
824 struct in6_addr *in6;
825 int s;
826
827 in6 = &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr;
828
829 /*
830 * Lock to protect the default router list.
831 * XXX: this might be unnecessary, since this function
832 * is only called under the network software interrupt
833 * context. However, we keep it just for safety.
834 */
835 s = splnet();
836 dr = defrouter_lookup(in6, ifp);
837 if (dr)
838 defrtrlist_del(dr);
839 else if (!V_ip6_forwarding) {
840 /*
841 * Even if the neighbor is not in the default
842 * router list, the neighbor may be used
843 * as a next hop for some destinations
844 * (e.g. redirect case). So we must
845 * call rt6_flush explicitly.
846 */
847 rt6_flush(&ip6->ip6_src, ifp);
848 }
849 splx(s);
850 }
851 ln->ln_router = is_router;
852 }
853 rt->rt_flags &= ~RTF_REJECT;
854 ln->ln_asked = 0;
855 if (ln->ln_hold) {
856 struct mbuf *m_hold, *m_hold_next;
857
858 /*
859 * reset the ln_hold in advance, to explicitly
860 * prevent a ln_hold lookup in nd6_output()
861 * (wouldn't happen, though...)
862 */
863 for (m_hold = ln->ln_hold;
864 m_hold; m_hold = m_hold_next) {
865 m_hold_next = m_hold->m_nextpkt;
866 m_hold->m_nextpkt = NULL;
867 /*
868 * we assume ifp is not a loopback here, so just set
869 * the 2nd argument as the 1st one.
870 */
871 nd6_output(ifp, ifp, m_hold,
872 (struct sockaddr_in6 *)rt_key(rt), rt);
873 }
874 ln->ln_hold = NULL;
875 }
876
877 freeit:
878 m_freem(m);
879 return;
880
881 bad:
882 V_icmp6stat.icp6s_badna++;
883 m_freem(m);
884 }
885
886 /*
887 * Neighbor advertisement output handling.
888 *
889 * Based on RFC 2461
890 *
891 * the following items are not implemented yet:
892 * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
893 * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
894 *
895 * tlladdr - 1 if include target link-layer address
896 * sdl0 - sockaddr_dl (= proxy NA) or NULL
897 */
898 void
899 nd6_na_output(struct ifnet *ifp, const struct in6_addr *daddr6_0,
900 const struct in6_addr *taddr6, u_long flags, int tlladdr,
901 struct sockaddr *sdl0)
902 {
903 INIT_VNET_INET6(ifp->if_vnet);
904 struct mbuf *m;
905 struct ip6_hdr *ip6;
906 struct nd_neighbor_advert *nd_na;
907 struct ip6_moptions im6o;
908 struct in6_addr *src, daddr6;
909 struct sockaddr_in6 dst_sa;
910 int icmp6len, maxlen, error;
911 caddr_t mac = NULL;
912 struct route_in6 ro;
913
914 bzero(&ro, sizeof(ro));
915
916 daddr6 = *daddr6_0; /* make a local copy for modification */
917
918 /* estimate the size of message */
919 maxlen = sizeof(*ip6) + sizeof(*nd_na);
920 maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
921 if (max_linkhdr + maxlen >= MCLBYTES) {
922 #ifdef DIAGNOSTIC
923 printf("nd6_na_output: max_linkhdr + maxlen >= MCLBYTES "
924 "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
925 #endif
926 return;
927 }
928
929 MGETHDR(m, M_DONTWAIT, MT_DATA);
930 if (m && max_linkhdr + maxlen >= MHLEN) {
931 MCLGET(m, M_DONTWAIT);
932 if ((m->m_flags & M_EXT) == 0) {
933 m_free(m);
934 m = NULL;
935 }
936 }
937 if (m == NULL)
938 return;
939 m->m_pkthdr.rcvif = NULL;
940
941 if (IN6_IS_ADDR_MULTICAST(&daddr6)) {
942 m->m_flags |= M_MCAST;
943 im6o.im6o_multicast_ifp = ifp;
944 im6o.im6o_multicast_hlim = 255;
945 im6o.im6o_multicast_loop = 0;
946 }
947
948 icmp6len = sizeof(*nd_na);
949 m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
950 m->m_data += max_linkhdr; /* or MH_ALIGN() equivalent? */
951
952 /* fill neighbor advertisement packet */
953 ip6 = mtod(m, struct ip6_hdr *);
954 ip6->ip6_flow = 0;
955 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
956 ip6->ip6_vfc |= IPV6_VERSION;
957 ip6->ip6_nxt = IPPROTO_ICMPV6;
958 ip6->ip6_hlim = 255;
959 if (IN6_IS_ADDR_UNSPECIFIED(&daddr6)) {
960 /* reply to DAD */
961 daddr6.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
962 daddr6.s6_addr16[1] = 0;
963 daddr6.s6_addr32[1] = 0;
964 daddr6.s6_addr32[2] = 0;
965 daddr6.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
966 if (in6_setscope(&daddr6, ifp, NULL))
967 goto bad;
968
969 flags &= ~ND_NA_FLAG_SOLICITED;
970 }
971 ip6->ip6_dst = daddr6;
972 bzero(&dst_sa, sizeof(struct sockaddr_in6));
973 dst_sa.sin6_family = AF_INET6;
974 dst_sa.sin6_len = sizeof(struct sockaddr_in6);
975 dst_sa.sin6_addr = daddr6;
976
977 /*
978 * Select a source whose scope is the same as that of the dest.
979 */
980 bcopy(&dst_sa, &ro.ro_dst, sizeof(dst_sa));
981 src = in6_selectsrc(&dst_sa, NULL, NULL, &ro, NULL, NULL, &error);
982 if (src == NULL) {
983 char ip6buf[INET6_ADDRSTRLEN];
984 nd6log((LOG_DEBUG, "nd6_na_output: source can't be "
985 "determined: dst=%s, error=%d\n",
986 ip6_sprintf(ip6buf, &dst_sa.sin6_addr), error));
987 goto bad;
988 }
989 ip6->ip6_src = *src;
990 nd_na = (struct nd_neighbor_advert *)(ip6 + 1);
991 nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
992 nd_na->nd_na_code = 0;
993 nd_na->nd_na_target = *taddr6;
994 in6_clearscope(&nd_na->nd_na_target); /* XXX */
995
996 /*
997 * "tlladdr" indicates NS's condition for adding tlladdr or not.
998 * see nd6_ns_input() for details.
999 * Basically, if NS packet is sent to unicast/anycast addr, |