1 /* $OpenBSD: nd6_rtr.c,v 1.33 2004/11/17 03:22:31 itojun Exp $ */
2 /* $KAME: nd6_rtr.c,v 1.97 2001/02/07 11:09:13 itojun Exp $ */
3
4 /*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/malloc.h>
36 #include <sys/mbuf.h>
37 #include <sys/socket.h>
38 #include <sys/sockio.h>
39 #include <sys/time.h>
40 #include <sys/kernel.h>
41 #include <sys/errno.h>
42 #include <sys/ioctl.h>
43 #include <sys/syslog.h>
44 #include <dev/rndvar.h>
45
46 #include <net/if.h>
47 #include <net/if_types.h>
48 #include <net/if_dl.h>
49 #include <net/route.h>
50 #include <net/radix.h>
51
52 #include <netinet/in.h>
53 #include <netinet6/in6_var.h>
54 #include <netinet/ip6.h>
55 #include <netinet6/ip6_var.h>
56 #include <netinet6/nd6.h>
57 #include <netinet/icmp6.h>
58
59 #define SDL(s) ((struct sockaddr_dl *)s)
60
61 static int rtpref(struct nd_defrouter *);
62 static struct nd_defrouter *defrtrlist_update(struct nd_defrouter *);
63 static struct in6_ifaddr *in6_ifadd(struct nd_prefix *);
64 static struct nd_pfxrouter *pfxrtr_lookup(struct nd_prefix *,
65 struct nd_defrouter *);
66 static void pfxrtr_add(struct nd_prefix *, struct nd_defrouter *);
67 static void pfxrtr_del(struct nd_pfxrouter *);
68 static struct nd_pfxrouter *find_pfxlist_reachable_router(struct nd_prefix *);
69 static void defrouter_delreq(struct nd_defrouter *);
70 static void nd6_rtmsg(int, struct rtentry *);
71
72 static void in6_init_address_ltimes(struct nd_prefix *,
73 struct in6_addrlifetime *);
74
75 static int rt6_deleteroute(struct radix_node *, void *);
76
77 extern int nd6_recalc_reachtm_interval;
78
79 static struct ifnet *nd6_defifp;
80 int nd6_defifindex;
81
82 /*
83 * Receive Router Solicitation Message - just for routers.
84 * Router solicitation/advertisement is mostly managed by userland program
85 * (rtadvd) so here we have no function like nd6_ra_output().
86 *
87 * Based on RFC 2461
88 */
89 void
nd6_rs_input(m,off,icmp6len)90 nd6_rs_input(m, off, icmp6len)
91 struct mbuf *m;
92 int off, icmp6len;
93 {
94 struct ifnet *ifp = m->m_pkthdr.rcvif;
95 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
96 struct nd_router_solicit *nd_rs;
97 struct in6_addr saddr6 = ip6->ip6_src;
98 #if 0
99 struct in6_addr daddr6 = ip6->ip6_dst;
100 #endif
101 char *lladdr = NULL;
102 int lladdrlen = 0;
103 #if 0
104 struct sockaddr_dl *sdl = (struct sockaddr_dl *)NULL;
105 struct llinfo_nd6 *ln = (struct llinfo_nd6 *)NULL;
106 struct rtentry *rt = NULL;
107 int is_newentry;
108 #endif
109 union nd_opts ndopts;
110
111 /* If I'm not a router, ignore it. */
112 if (ip6_accept_rtadv != 0 || !ip6_forwarding)
113 goto freeit;
114
115 /* Sanity checks */
116 if (ip6->ip6_hlim != 255) {
117 nd6log((LOG_ERR,
118 "nd6_rs_input: invalid hlim (%d) from %s to %s on %s\n",
119 ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
120 ip6_sprintf(&ip6->ip6_dst), ifp->if_xname));
121 goto bad;
122 }
123
124 /*
125 * Don't update the neighbor cache, if src = ::.
126 * This indicates that the src has no IP address assigned yet.
127 */
128 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
129 goto freeit;
130
131 IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off, icmp6len);
132 if (nd_rs == NULL) {
133 icmp6stat.icp6s_tooshort++;
134 return;
135 }
136
137 icmp6len -= sizeof(*nd_rs);
138 nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
139 if (nd6_options(&ndopts) < 0) {
140 nd6log((LOG_INFO,
141 "nd6_rs_input: invalid ND option, ignored\n"));
142 /* nd6_options have incremented stats */
143 goto freeit;
144 }
145
146 if (ndopts.nd_opts_src_lladdr) {
147 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
148 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
149 }
150
151 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
152 nd6log((LOG_INFO,
153 "nd6_rs_input: lladdrlen mismatch for %s "
154 "(if %d, RS packet %d)\n",
155 ip6_sprintf(&saddr6), ifp->if_addrlen, lladdrlen - 2));
156 goto bad;
157 }
158
159 nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_SOLICIT, 0);
160
161 freeit:
162 m_freem(m);
163 return;
164
165 bad:
166 icmp6stat.icp6s_badrs++;
167 m_freem(m);
168 }
169
170 /*
171 * Receive Router Advertisement Message.
172 *
173 * Based on RFC 2461
174 * TODO: on-link bit on prefix information
175 * TODO: ND_RA_FLAG_{OTHER,MANAGED} processing
176 */
177 void
nd6_ra_input(m,off,icmp6len)178 nd6_ra_input(m, off, icmp6len)
179 struct mbuf *m;
180 int off, icmp6len;
181 {
182 struct ifnet *ifp = m->m_pkthdr.rcvif;
183 struct nd_ifinfo *ndi = ND_IFINFO(ifp);
184 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
185 struct nd_router_advert *nd_ra;
186 struct in6_addr saddr6 = ip6->ip6_src;
187 #if 0
188 struct in6_addr daddr6 = ip6->ip6_dst;
189 int flags; /* = nd_ra->nd_ra_flags_reserved; */
190 int is_managed = ((flags & ND_RA_FLAG_MANAGED) != 0);
191 int is_other = ((flags & ND_RA_FLAG_OTHER) != 0);
192 #endif
193 union nd_opts ndopts;
194 struct nd_defrouter *dr;
195
196 /*
197 * We only accept RAs only when
198 * the system-wide variable allows the acceptance, and
199 * per-interface variable allows RAs on the receiving interface.
200 */
201 if (ip6_accept_rtadv == 0)
202 goto freeit;
203 if (!(ndi->flags & ND6_IFF_ACCEPT_RTADV))
204 goto freeit;
205
206 if (ip6->ip6_hlim != 255) {
207 nd6log((LOG_ERR,
208 "nd6_ra_input: invalid hlim (%d) from %s to %s on %s\n",
209 ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
210 ip6_sprintf(&ip6->ip6_dst), ifp->if_xname));
211 goto bad;
212 }
213
214 if (!IN6_IS_ADDR_LINKLOCAL(&saddr6)) {
215 nd6log((LOG_ERR,
216 "nd6_ra_input: src %s is not link-local\n",
217 ip6_sprintf(&saddr6)));
218 goto bad;
219 }
220
221 IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off, icmp6len);
222 if (nd_ra == NULL) {
223 icmp6stat.icp6s_tooshort++;
224 return;
225 }
226
227 icmp6len -= sizeof(*nd_ra);
228 nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
229 if (nd6_options(&ndopts) < 0) {
230 nd6log((LOG_INFO,
231 "nd6_ra_input: invalid ND option, ignored\n"));
232 /* nd6_options have incremented stats */
233 goto freeit;
234 }
235
236 {
237 struct nd_defrouter dr0;
238 u_int32_t advreachable = nd_ra->nd_ra_reachable;
239
240 Bzero(&dr0, sizeof(dr0));
241 dr0.rtaddr = saddr6;
242 dr0.flags = nd_ra->nd_ra_flags_reserved;
243 dr0.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);
244 dr0.expire = time.tv_sec + dr0.rtlifetime;
245 dr0.ifp = ifp;
246 /* unspecified or not? (RFC 2461 6.3.4) */
247 if (advreachable) {
248 NTOHL(advreachable);
249 if (advreachable <= MAX_REACHABLE_TIME &&
250 ndi->basereachable != advreachable) {
251 ndi->basereachable = advreachable;
252 ndi->reachable = ND_COMPUTE_RTIME(ndi->basereachable);
253 ndi->recalctm = nd6_recalc_reachtm_interval; /* reset */
254 }
255 }
256 if (nd_ra->nd_ra_retransmit)
257 ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
258 if (nd_ra->nd_ra_curhoplimit)
259 ndi->chlim = nd_ra->nd_ra_curhoplimit;
260 dr = defrtrlist_update(&dr0);
261 }
262
263 /*
264 * prefix
265 */
266 if (ndopts.nd_opts_pi) {
267 struct nd_opt_hdr *pt;
268 struct nd_opt_prefix_info *pi = NULL;
269 struct nd_prefix pr;
270
271 for (pt = (struct nd_opt_hdr *)ndopts.nd_opts_pi;
272 pt <= (struct nd_opt_hdr *)ndopts.nd_opts_pi_end;
273 pt = (struct nd_opt_hdr *)((caddr_t)pt +
274 (pt->nd_opt_len << 3))) {
275 if (pt->nd_opt_type != ND_OPT_PREFIX_INFORMATION)
276 continue;
277 pi = (struct nd_opt_prefix_info *)pt;
278
279 if (pi->nd_opt_pi_len != 4) {
280 nd6log((LOG_INFO,
281 "nd6_ra_input: invalid option "
282 "len %d for prefix information option, "
283 "ignored\n", pi->nd_opt_pi_len));
284 continue;
285 }
286
287 if (128 < pi->nd_opt_pi_prefix_len) {
288 nd6log((LOG_INFO,
289 "nd6_ra_input: invalid prefix "
290 "len %d for prefix information option, "
291 "ignored\n", pi->nd_opt_pi_prefix_len));
292 continue;
293 }
294
295 if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix)
296 || IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix)) {
297 nd6log((LOG_INFO,
298 "nd6_ra_input: invalid prefix "
299 "%s, ignored\n",
300 ip6_sprintf(&pi->nd_opt_pi_prefix)));
301 continue;
302 }
303
304 /* aggregatable unicast address, rfc2374 */
305 if ((pi->nd_opt_pi_prefix.s6_addr8[0] & 0xe0) == 0x20
306 && pi->nd_opt_pi_prefix_len != 64) {
307 nd6log((LOG_INFO,
308 "nd6_ra_input: invalid prefixlen "
309 "%d for rfc2374 prefix %s, ignored\n",
310 pi->nd_opt_pi_prefix_len,
311 ip6_sprintf(&pi->nd_opt_pi_prefix)));
312 continue;
313 }
314
315 bzero(&pr, sizeof(pr));
316 pr.ndpr_prefix.sin6_family = AF_INET6;
317 pr.ndpr_prefix.sin6_len = sizeof(pr.ndpr_prefix);
318 pr.ndpr_prefix.sin6_addr = pi->nd_opt_pi_prefix;
319 pr.ndpr_ifp = (struct ifnet *)m->m_pkthdr.rcvif;
320
321 pr.ndpr_raf_onlink = (pi->nd_opt_pi_flags_reserved &
322 ND_OPT_PI_FLAG_ONLINK) ? 1 : 0;
323 pr.ndpr_raf_auto = (pi->nd_opt_pi_flags_reserved &
324 ND_OPT_PI_FLAG_AUTO) ? 1 : 0;
325 pr.ndpr_plen = pi->nd_opt_pi_prefix_len;
326 pr.ndpr_vltime = ntohl(pi->nd_opt_pi_valid_time);
327 pr.ndpr_pltime = ntohl(pi->nd_opt_pi_preferred_time);
328 pr.ndpr_lastupdate = time.tv_sec;
329
330 if (in6_init_prefix_ltimes(&pr))
331 continue; /* prefix lifetime init failed */
332
333 (void)prelist_update(&pr, dr, m);
334 }
335 }
336
337 /*
338 * MTU
339 */
340 if (ndopts.nd_opts_mtu && ndopts.nd_opts_mtu->nd_opt_mtu_len == 1) {
341 u_long mtu;
342 u_long maxmtu;
343
344 mtu = ntohl(ndopts.nd_opts_mtu->nd_opt_mtu_mtu);
345
346 /* lower bound */
347 if (mtu < IPV6_MMTU) {
348 nd6log((LOG_INFO, "nd6_ra_input: bogus mtu option "
349 "mtu=%lu sent from %s, ignoring\n",
350 mtu, ip6_sprintf(&ip6->ip6_src)));
351 goto skip;
352 }
353
354 /* upper bound */
355 maxmtu = (ndi->maxmtu && ndi->maxmtu < ifp->if_mtu)
356 ? ndi->maxmtu : ifp->if_mtu;
357 if (mtu <= maxmtu) {
358 int change = (ndi->linkmtu != mtu);
359
360 ndi->linkmtu = mtu;
361 if (change) /* in6_maxmtu may change */
362 in6_setmaxmtu();
363 } else {
364 nd6log((LOG_INFO, "nd6_ra_input: bogus mtu "
365 "mtu=%lu sent from %s; "
366 "exceeds maxmtu %lu, ignoring\n",
367 mtu, ip6_sprintf(&ip6->ip6_src), maxmtu));
368 }
369 }
370
371 skip:
372
373 /*
374 * Source link layer address
375 */
376 {
377 char *lladdr = NULL;
378 int lladdrlen = 0;
379
380 if (ndopts.nd_opts_src_lladdr) {
381 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
382 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
383 }
384
385 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
386 nd6log((LOG_INFO,
387 "nd6_ra_input: lladdrlen mismatch for %s "
388 "(if %d, RA packet %d)\n", ip6_sprintf(&saddr6),
389 ifp->if_addrlen, lladdrlen - 2));
390 goto bad;
391 }
392
393 nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_ADVERT, 0);
394
395 /*
396 * Installing a link-layer address might change the state of the
397 * router's neighbor cache, which might also affect our on-link
398 * detection of adveritsed prefixes.
399 */
400 pfxlist_onlink_check();
401 }
402
403 freeit:
404 m_freem(m);
405 return;
406
407 bad:
408 icmp6stat.icp6s_badra++;
409 m_freem(m);
410 }
411
412 /*
413 * default router list processing sub routines
414 */
415
416 /* tell the change to user processes watching the routing socket. */
417 static void
nd6_rtmsg(cmd,rt)418 nd6_rtmsg(cmd, rt)
419 int cmd;
420 struct rtentry *rt;
421 {
422 struct rt_addrinfo info;
423
424 bzero((caddr_t)&info, sizeof(info));
425 info.rti_info[RTAX_DST] = rt_key(rt);
426 info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
427 info.rti_info[RTAX_NETMASK] = rt_mask(rt);
428 if (rt->rt_ifp) {
429 info.rti_info[RTAX_IFP] =
430 TAILQ_FIRST(&rt->rt_ifp->if_addrlist)->ifa_addr;
431 info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
432 }
433
434 rt_missmsg(cmd, &info, rt->rt_flags, 0);
435 }
436
437 void
defrouter_addreq(new)438 defrouter_addreq(new)
439 struct nd_defrouter *new;
440 {
441 struct sockaddr_in6 def, mask, gate;
442 struct rtentry *newrt = NULL;
443 int s;
444 int error;
445
446 Bzero(&def, sizeof(def));
447 Bzero(&mask, sizeof(mask));
448 Bzero(&gate, sizeof(gate)); /* for safety */
449
450 def.sin6_len = mask.sin6_len = gate.sin6_len =
451 sizeof(struct sockaddr_in6);
452 def.sin6_family = mask.sin6_family = gate.sin6_family = AF_INET6;
453 gate.sin6_addr = new->rtaddr;
454 #ifndef SCOPEDROUTING
455 gate.sin6_scope_id = 0; /* XXX */
456 #endif
457
458 s = splsoftnet();
459 error = rtrequest(RTM_ADD, (struct sockaddr *)&def,
460 (struct sockaddr *)&gate, (struct sockaddr *)&mask,
461 RTF_GATEWAY, &newrt);
462 if (newrt) {
463 nd6_rtmsg(RTM_ADD, newrt); /* tell user process */
464 newrt->rt_refcnt--;
465 }
466 if (error == 0)
467 new->installed = 1;
468 splx(s);
469 return;
470 }
471
472 struct nd_defrouter *
defrouter_lookup(addr,ifp)473 defrouter_lookup(addr, ifp)
474 struct in6_addr *addr;
475 struct ifnet *ifp;
476 {
477 struct nd_defrouter *dr;
478
479 for (dr = TAILQ_FIRST(&nd_defrouter); dr;
480 dr = TAILQ_NEXT(dr, dr_entry)) {
481 if (dr->ifp == ifp && IN6_ARE_ADDR_EQUAL(addr, &dr->rtaddr)) {
482 return (dr);
483 }
484 }
485
486 return (NULL); /* search failed */
487 }
488
489 void
defrtrlist_del(dr)490 defrtrlist_del(dr)
491 struct nd_defrouter *dr;
492 {
493 struct nd_defrouter *deldr = NULL;
494 struct nd_prefix *pr;
495
496 /*
497 * Flush all the routing table entries that use the router
498 * as a next hop.
499 */
500 if (!ip6_forwarding && ip6_accept_rtadv) /* XXX: better condition? */
501 rt6_flush(&dr->rtaddr, dr->ifp);
502
503 if (dr->installed) {
504 deldr = dr;
505 defrouter_delreq(dr);
506 }
507 TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
508
509 /*
510 * Also delete all the pointers to the router in each prefix lists.
511 */
512 for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
513 struct nd_pfxrouter *pfxrtr;
514 if ((pfxrtr = pfxrtr_lookup(pr, dr)) != NULL)
515 pfxrtr_del(pfxrtr);
516 }
517 pfxlist_onlink_check();
518
519 /*
520 * If the router is the primary one, choose a new one.
521 * Note that defrouter_select() will remove the current gateway
522 * from the routing table.
523 */
524 if (deldr)
525 defrouter_select();
526
527 free(dr, M_IP6NDP);
528 }
529
530 /*
531 * Remove the default route for a given router.
532 * This is just a subroutine function for defrouter_select(), and should
533 * not be called from anywhere else.
534 */
535 static void
defrouter_delreq(dr)536 defrouter_delreq(dr)
537 struct nd_defrouter *dr;
538 {
539 struct sockaddr_in6 def, mask, gw;
540 struct rtentry *oldrt = NULL;
541
542 #ifdef DIAGNOSTIC
543 if (!dr)
544 panic("dr == NULL in defrouter_delreq");
545 #endif
546
547 Bzero(&def, sizeof(def));
548 Bzero(&mask, sizeof(mask));
549 Bzero(&gw, sizeof(gw)); /* for safety */
550
551 def.sin6_len = mask.sin6_len = gw.sin6_len =
552 sizeof(struct sockaddr_in6);
553 def.sin6_family = mask.sin6_family = gw.sin6_family = AF_INET6;
554 gw.sin6_addr = dr->rtaddr;
555 #ifndef SCOPEDROUTING
556 gw.sin6_scope_id = 0; /* XXX */
557 #endif
558
559 rtrequest(RTM_DELETE, (struct sockaddr *)&def,
560 (struct sockaddr *)&gw,
561 (struct sockaddr *)&mask, RTF_GATEWAY, &oldrt);
562 if (oldrt) {
563 nd6_rtmsg(RTM_DELETE, oldrt);
564 if (oldrt->rt_refcnt <= 0) {
565 /*
566 * XXX: borrowed from the RTM_DELETE case of
567 * rtrequest().
568 */
569 oldrt->rt_refcnt++;
570 rtfree(oldrt);
571 }
572 }
573
574 dr->installed = 0;
575 }
576
577 /*
578 * remove all default routes from default router list
579 */
580 void
defrouter_reset()581 defrouter_reset()
582 {
583 struct nd_defrouter *dr;
584
585 for (dr = TAILQ_FIRST(&nd_defrouter); dr;
586 dr = TAILQ_NEXT(dr, dr_entry))
587 defrouter_delreq(dr);
588
589 /*
590 * XXX should we also nuke any default routers in the kernel, by
591 * going through them by rtalloc1()?
592 */
593 }
594
595 /*
596 * Default Router Selection according to Section 6.3.6 of RFC 2461 and
597 * draft-ietf-ipngwg-router-selection:
598 * 1) Routers that are reachable or probably reachable should be preferred.
599 * If we have more than one (probably) reachable router, prefer ones
600 * with the highest router preference.
601 * 2) When no routers on the list are known to be reachable or
602 * probably reachable, routers SHOULD be selected in a round-robin
603 * fashion, regardless of router preference values.
604 * 3) If the Default Router List is empty, assume that all
605 * destinations are on-link.
606 *
607 * We assume nd_defrouter is sorted by router preference value.
608 * Since the code below covers both with and without router preference cases,
609 * we do not need to classify the cases by ifdef.
610 *
611 * At this moment, we do not try to install more than one default router,
612 * even when the multipath routing is available, because we're not sure about
613 * the benefits for stub hosts comparing to the risk of making the code
614 * complicated and the possibility of introducing bugs.
615 */
616 void
defrouter_select()617 defrouter_select()
618 {
619 int s = splsoftnet();
620 struct nd_defrouter *dr, *selected_dr = NULL, *installed_dr = NULL;
621 struct rtentry *rt = NULL;
622 struct llinfo_nd6 *ln = NULL;
623
624 /*
625 * This function should be called only when acting as an autoconfigured
626 * host. Although the remaining part of this function is not effective
627 * if the node is not an autoconfigured host, we explicitly exclude
628 * such cases here for safety.
629 */
630 if (ip6_forwarding || !ip6_accept_rtadv) {
631 nd6log((LOG_WARNING,
632 "defrouter_select: called unexpectedly (forwarding=%d, "
633 "accept_rtadv=%d)\n", ip6_forwarding, ip6_accept_rtadv));
634 splx(s);
635 return;
636 }
637
638 /*
639 * Let's handle easy case (3) first:
640 * If default router list is empty, there's nothing to be done.
641 */
642 if (!TAILQ_FIRST(&nd_defrouter)) {
643 splx(s);
644 return;
645 }
646
647 /*
648 * Search for a (probably) reachable router from the list.
649 * We just pick up the first reachable one (if any), assuming that
650 * the ordering rule of the list described in defrtrlist_update().
651 */
652 for (dr = TAILQ_FIRST(&nd_defrouter); dr;
653 dr = TAILQ_NEXT(dr, dr_entry)) {
654 if (!selected_dr &&
655 (rt = nd6_lookup(&dr->rtaddr, 0, dr->ifp)) &&
656 (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
657 ND6_IS_LLINFO_PROBREACH(ln)) {
658 selected_dr = dr;
659 }
660
661 if (dr->installed && !installed_dr)
662 installed_dr = dr;
663 else if (dr->installed && installed_dr) {
664 /* this should not happen. warn for diagnosis. */
665 log(LOG_ERR, "defrouter_select: more than one router"
666 " is installed\n");
667 }
668 }
669 /*
670 * If none of the default routers was found to be reachable,
671 * round-robin the list regardless of preference.
672 * Otherwise, if we have an installed router, check if the selected
673 * (reachable) router should really be preferred to the installed one.
674 * We only prefer the new router when the old one is not reachable
675 * or when the new one has a really higher preference value.
676 */
677 if (!selected_dr) {
678 if (!installed_dr || !TAILQ_NEXT(installed_dr, dr_entry))
679 selected_dr = TAILQ_FIRST(&nd_defrouter);
680 else
681 selected_dr = TAILQ_NEXT(installed_dr, dr_entry);
682 } else if (installed_dr &&
683 (rt = nd6_lookup(&installed_dr->rtaddr, 0, installed_dr->ifp)) &&
684 (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
685 ND6_IS_LLINFO_PROBREACH(ln) &&
686 rtpref(selected_dr) <= rtpref(installed_dr)) {
687 selected_dr = installed_dr;
688 }
689
690 /*
691 * If the selected router is different than the installed one,
692 * remove the installed router and install the selected one.
693 * Note that the selected router is never NULL here.
694 */
695 if (installed_dr != selected_dr) {
696 if (installed_dr)
697 defrouter_delreq(installed_dr);
698 defrouter_addreq(selected_dr);
699 }
700
701 splx(s);
702 return;
703 }
704
705 /*
706 * for default router selection
707 * regards router-preference field as a 2-bit signed integer
708 */
709 static int
rtpref(struct nd_defrouter * dr)710 rtpref(struct nd_defrouter *dr)
711 {
712 #ifdef RTPREF
713 switch (dr->flags & ND_RA_FLAG_RTPREF_MASK) {
714 case ND_RA_FLAG_RTPREF_HIGH:
715 return RTPREF_HIGH;
716 case ND_RA_FLAG_RTPREF_MEDIUM:
717 case ND_RA_FLAG_RTPREF_RSV:
718 return RTPREF_MEDIUM;
719 case ND_RA_FLAG_RTPREF_LOW:
720 return RTPREF_LOW;
721 default:
722 /*
723 * This case should never happen. If it did, it would mean a
724 * serious bug of kernel internal. We thus always bark here.
725 * Or, can we even panic?
726 */
727 log(LOG_ERR, "rtpref: impossible RA flag %x", dr->flags);
728 return RTPREF_INVALID;
729 }
730 /* NOTREACHED */
731 #else
732 return 0;
733 #endif
734 }
735
736 static struct nd_defrouter *
defrtrlist_update(new)737 defrtrlist_update(new)
738 struct nd_defrouter *new;
739 {
740 struct nd_defrouter *dr, *n;
741 int s = splsoftnet();
742
743 if ((dr = defrouter_lookup(&new->rtaddr, new->ifp)) != NULL) {
744 /* entry exists */
745 if (new->rtlifetime == 0) {
746 defrtrlist_del(dr);
747 dr = NULL;
748 } else {
749 int oldpref = rtpref(dr);
750
751 /* override */
752 dr->flags = new->flags; /* xxx flag check */
753 dr->rtlifetime = new->rtlifetime;
754 dr->expire = new->expire;
755
756 /*
757 * If the preference does not change, there's no need
758 * to sort the entries.
759 */
760 if (rtpref(new) == oldpref) {
761 splx(s);
762 return (dr);
763 }
764
765 /*
766 * preferred router may be changed, so relocate
767 * this router.
768 * XXX: calling TAILQ_REMOVE directly is a bad manner.
769 * However, since defrtrlist_del() has many side
770 * effects, we intentionally do so here.
771 * defrouter_select() below will handle routing
772 * changes later.
773 */
774 TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
775 n = dr;
776 goto insert;
777 }
778 splx(s);
779 return (dr);
780 }
781
782 /* entry does not exist */
783 if (new->rtlifetime == 0) {
784 splx(s);
785 return (NULL);
786 }
787
788 n = (struct nd_defrouter *)malloc(sizeof(*n), M_IP6NDP, M_NOWAIT);
789 if (n == NULL) {
790 splx(s);
791 return (NULL);
792 }
793 bzero(n, sizeof(*n));
794 *n = *new;
795
796 insert:
797 /*
798 * Insert the new router in the Default Router List;
799 * The Default Router List should be in the descending order
800 * of router-preferece. Routers with the same preference are
801 * sorted in the arriving time order.
802 */
803
804 /* insert at the end of the group */
805 for (dr = TAILQ_FIRST(&nd_defrouter); dr;
806 dr = TAILQ_NEXT(dr, dr_entry)) {
807 if (rtpref(n) > rtpref(dr))
808 break;
809 }
810 if (dr)
811 TAILQ_INSERT_BEFORE(dr, n, dr_entry);
812 else
813 TAILQ_INSERT_TAIL(&nd_defrouter, n, dr_entry);
814
815 defrouter_select();
816
817 splx(s);
818
819 return (n);
820 }
821
822 static struct nd_pfxrouter *
pfxrtr_lookup(pr,dr)823 pfxrtr_lookup(pr, dr)
824 struct nd_prefix *pr;
825 struct nd_defrouter *dr;
826 {
827 struct nd_pfxrouter *search;
828
829 for (search = pr->ndpr_advrtrs.lh_first; search; search = search->pfr_next) {
830 if (search->router == dr)
831 break;
832 }
833
834 return (search);
835 }
836
837 static void
pfxrtr_add(pr,dr)838 pfxrtr_add(pr, dr)
839 struct nd_prefix *pr;
840 struct nd_defrouter *dr;
841 {
842 struct nd_pfxrouter *new;
843
844 new = (struct nd_pfxrouter *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
845 if (new == NULL)
846 return;
847 bzero(new, sizeof(*new));
848 new->router = dr;
849
850 LIST_INSERT_HEAD(&pr->ndpr_advrtrs, new, pfr_entry);
851
852 pfxlist_onlink_check();
853 }
854
855 static void
pfxrtr_del(pfr)856 pfxrtr_del(pfr)
857 struct nd_pfxrouter *pfr;
858 {
859 LIST_REMOVE(pfr, pfr_entry);
860 free(pfr, M_IP6NDP);
861 }
862
863 struct nd_prefix *
nd6_prefix_lookup(pr)864 nd6_prefix_lookup(pr)
865 struct nd_prefix *pr;
866 {
867 struct nd_prefix *search;
868
869 for (search = nd_prefix.lh_first; search; search = search->ndpr_next) {
870 if (pr->ndpr_ifp == search->ndpr_ifp &&
871 pr->ndpr_plen == search->ndpr_plen &&
872 in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
873 &search->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
874 break;
875 }
876 }
877
878 return (search);
879 }
880
881 int
nd6_prelist_add(pr,dr,newp)882 nd6_prelist_add(pr, dr, newp)
883 struct nd_prefix *pr, **newp;
884 struct nd_defrouter *dr;
885 {
886 struct nd_prefix *new = NULL;
887 int i, s;
888
889 new = (struct nd_prefix *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
890 if (new == NULL)
891 return ENOMEM;
892 bzero(new, sizeof(*new));
893 *new = *pr;
894 if (newp != NULL)
895 *newp = new;
896
897 /* initilization */
898 LIST_INIT(&new->ndpr_advrtrs);
899 in6_prefixlen2mask(&new->ndpr_mask, new->ndpr_plen);
900 /* make prefix in the canonical form */
901 for (i = 0; i < 4; i++)
902 new->ndpr_prefix.sin6_addr.s6_addr32[i] &=
903 new->ndpr_mask.s6_addr32[i];
904
905 s = splsoftnet();
906 /* link ndpr_entry to nd_prefix list */
907 LIST_INSERT_HEAD(&nd_prefix, new, ndpr_entry);
908 splx(s);
909
910 /* ND_OPT_PI_FLAG_ONLINK processing */
911 if (new->ndpr_raf_onlink) {
912 int e;
913
914 if ((e = nd6_prefix_onlink(new)) != 0) {
915 nd6log((LOG_ERR, "nd6_prelist_add: failed to make "
916 "the prefix %s/%d on-link on %s (errno=%d)\n",
917 ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
918 pr->ndpr_plen, pr->ndpr_ifp->if_xname, e));
919 /* proceed anyway. XXX: is it correct? */
920 }
921 }
922
923 if (dr)
924 pfxrtr_add(new, dr);
925
926 return 0;
927 }
928
929 void
prelist_remove(pr)930 prelist_remove(pr)
931 struct nd_prefix *pr;
932 {
933 struct nd_pfxrouter *pfr, *next;
934 int e, s;
935
936 /* make sure to invalidate the prefix until it is really freed. */
937 pr->ndpr_vltime = 0;
938 pr->ndpr_pltime = 0;
939 #if 0
940 /*
941 * Though these flags are now meaningless, we'd rather keep the value
942 * not to confuse users when executing "ndp -p".
943 */
944 pr->ndpr_raf_onlink = 0;
945 pr->ndpr_raf_auto = 0;
946 #endif
947 if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0 &&
948 (e = nd6_prefix_offlink(pr)) != 0) {
949 nd6log((LOG_ERR, "prelist_remove: failed to make %s/%d offlink "
950 "on %s, errno=%d\n",
951 ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
952 pr->ndpr_plen, pr->ndpr_ifp->if_xname, e));
953 /* what should we do? */
954 }
955
956 if (pr->ndpr_refcnt > 0)
957 return; /* notice here? */
958
959 s = splsoftnet();
960
961 /* unlink ndpr_entry from nd_prefix list */
962 LIST_REMOVE(pr, ndpr_entry);
963
964 /* free list of routers that adversed the prefix */
965 for (pfr = pr->ndpr_advrtrs.lh_first; pfr; pfr = next) {
966 next = pfr->pfr_next;
967
968 free(pfr, M_IP6NDP);
969 }
970 splx(s);
971
972 free(pr, M_IP6NDP);
973
974 pfxlist_onlink_check();
975 }
976
977 int
prelist_update(new,dr,m)978 prelist_update(new, dr, m)
979 struct nd_prefix *new;
980 struct nd_defrouter *dr; /* may be NULL */
981 struct mbuf *m;
982 {
983 struct in6_ifaddr *ia6 = NULL, *ia6_match = NULL;
984 struct ifaddr *ifa;
985 struct ifnet *ifp = new->ndpr_ifp;
986 struct nd_prefix *pr;
987 int s = splsoftnet();
988 int error = 0;
989 int newprefix = 0;
990 int auth;
991 struct in6_addrlifetime lt6_tmp;
992
993 auth = 0;
994 if (m) {
995 /*
996 * Authenticity for NA consists authentication for
997 * both IP header and IP datagrams, doesn't it ?
998 */
999 auth = ((m->m_flags & M_AUTH_AH) && (m->m_flags & M_AUTH));
1000 }
1001
1002 if ((pr = nd6_prefix_lookup(new)) != NULL) {
1003 /*
1004 * nd6_prefix_lookup() ensures that pr and new have the same
1005 * prefix on a same interface.
1006 */
1007
1008 /*
1009 * Update prefix information. Note that the on-link (L) bit
1010 * and the autonomous (A) bit should NOT be changed from 1
1011 * to 0.
1012 */
1013 if (new->ndpr_raf_onlink == 1)
1014 pr->ndpr_raf_onlink = 1;
1015 if (new->ndpr_raf_auto == 1)
1016 pr->ndpr_raf_auto = 1;
1017 if (new->ndpr_raf_onlink) {
1018 pr->ndpr_vltime = new->ndpr_vltime;
1019 pr->ndpr_pltime = new->ndpr_pltime;
1020 pr->ndpr_preferred = new->ndpr_preferred;
1021 pr->ndpr_expire = new->ndpr_expire;
1022 pr->ndpr_lastupdate = new->ndpr_lastupdate;
1023 }
1024
1025 if (new->ndpr_raf_onlink &&
1026 (pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
1027 int e;
1028
1029 if ((e = nd6_prefix_onlink(pr)) != 0) {
1030 nd6log((LOG_ERR,
1031 "prelist_update: failed to make "
1032 "the prefix %s/%d on-link on %s "
1033 "(errno=%d)\n",
1034 ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
1035 pr->ndpr_plen, pr->ndpr_ifp->if_xname, e));
1036 /* proceed anyway. XXX: is it correct? */
1037 }
1038 }
1039
1040 if (dr && pfxrtr_lookup(pr, dr) == NULL)
1041 pfxrtr_add(pr, dr);
1042 } else {
1043 struct nd_prefix *newpr = NULL;
1044
1045 newprefix = 1;
1046
1047 if (new->ndpr_vltime == 0)
1048 goto end;
1049 if (new->ndpr_raf_onlink == 0 && new->ndpr_raf_auto == 0)
1050 goto end;
1051
1052 error = nd6_prelist_add(new, dr, &newpr);
1053 if (error != 0 || newpr == NULL) {
1054 nd6log((LOG_NOTICE, "prelist_update: "
1055 "nd6_prelist_add failed for %s/%d on %s "
1056 "errno=%d, returnpr=%p\n",
1057 ip6_sprintf(&new->ndpr_prefix.sin6_addr),
1058 new->ndpr_plen, new->ndpr_ifp->if_xname,
1059 error, newpr));
1060 goto end; /* we should just give up in this case. */
1061 }
1062
1063 /*
1064 * XXX: from the ND point of view, we can ignore a prefix
1065 * with the on-link bit being zero. However, we need a
1066 * prefix structure for references from autoconfigured
1067 * addresses. Thus, we explicitly make sure that the prefix
1068 * itself expires now.
1069 */
1070 if (newpr->ndpr_raf_onlink == 0) {
1071 newpr->ndpr_vltime = 0;
1072 newpr->ndpr_pltime = 0;
1073 in6_init_prefix_ltimes(newpr);
1074 }
1075
1076 pr = newpr;
1077 }
1078
1079 /*
1080 * Address autoconfiguration based on Section 5.5.3 of RFC 2462.
1081 * Note that pr must be non NULL at this point.
1082 */
1083
1084 /* 5.5.3 (a). Ignore the prefix without the A bit set. */
1085 if (!new->ndpr_raf_auto)
1086 goto end;
1087
1088 /*
1089 * 5.5.3 (b). the link-local prefix should have been ignored in
1090 * nd6_ra_input.
1091 */
1092
1093 /*
1094 * 5.5.3 (c). Consistency check on lifetimes: pltime <= vltime.
1095 * This should have been done in nd6_ra_input.
1096 */
1097
1098 /*
1099 * 5.5.3 (d). If the prefix advertised does not match the prefix of an
1100 * address already in the list, and the Valid Lifetime is not 0,
1101 * form an address. Note that even a manually configured address
1102 * should reject autoconfiguration of a new address.
1103 */
1104 for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
1105 {
1106 struct in6_ifaddr *ifa6;
1107 int ifa_plen;
1108 u_int32_t storedlifetime;
1109
1110 if (ifa->ifa_addr->sa_family != AF_INET6)
1111 continue;
1112
1113 ifa6 = (struct in6_ifaddr *)ifa;
1114
1115 /*
1116 * Spec is not clear here, but I believe we should concentrate
1117 * on unicast (i.e. not anycast) addresses.
1118 * XXX: other ia6_flags? detached or duplicated?
1119 */
1120 if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0)
1121 continue;
1122
1123 ifa_plen = in6_mask2len(&ifa6->ia_prefixmask.sin6_addr, NULL);
1124 if (ifa_plen != new->ndpr_plen ||
1125 !in6_are_prefix_equal(&ifa6->ia_addr.sin6_addr,
1126 &new->ndpr_prefix.sin6_addr, ifa_plen))
1127 continue;
1128
1129 if (ia6_match == NULL) /* remember the first one */
1130 ia6_match = ifa6;
1131
1132 if ((ifa6->ia6_flags & IN6_IFF_AUTOCONF) == 0)
1133 continue;
1134
1135 /*
1136 * An already autoconfigured address matched. Now that we
1137 * are sure there is at least one matched address, we can
1138 * proceed to 5.5.3. (e): update the lifetimes according to the
1139 * "two hours" rule and the privacy extension.
1140 */
1141 #define TWOHOUR (120*60)
1142 /*
1143 * RFC2462 introduces the notion of StoredLifetime to the
1144 * "two hours" rule as follows:
1145 * the Lifetime associated with the previously autoconfigured
1146 * address.
1147 * Our interpretation of this definition is "the remaining
1148 * lifetime to expiration at the evaluation time". One might
1149 * be wondering if this interpretation is really conform to the
1150 * RFC, because the text can read that "Lifetimes" are never
1151 * decreased, and our definition of the "storedlifetime" below
1152 * essentially reduces the "Valid Lifetime" advertised in the
1153 * previous RA. But, this is due to the wording of the text,
1154 * and our interpretation is the same as an author's intention.
1155 * See the discussion in the IETF ipngwg ML in August 2001,
1156 * with the Subject "StoredLifetime in RFC 2462".
1157 */
1158 lt6_tmp = ifa6->ia6_lifetime;
1159 if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME)
1160 storedlifetime = ND6_INFINITE_LIFETIME;
1161 else if (time.tv_sec - ifa6->ia6_updatetime >
1162 lt6_tmp.ia6t_vltime) {
1163 /*
1164 * The case of "invalid" address. We should usually
1165 * not see this case.
1166 */
1167 storedlifetime = 0;
1168 } else
1169 storedlifetime = lt6_tmp.ia6t_vltime -
1170 (time.tv_sec - ifa6->ia6_updatetime);
1171 if (TWOHOUR < new->ndpr_vltime ||
1172 storedlifetime < new->ndpr_vltime) {
1173 lt6_tmp.ia6t_vltime = new->ndpr_vltime;
1174 } else if (storedlifetime <= TWOHOUR
1175 #if 0
1176 /*
1177 * This condition is logically redundant, so we just
1178 * omit it.
1179 * See IPng 6712, 6717, and 6721.
1180 */
1181 && new->ndpr_vltime <= storedlifetime
1182 #endif
1183 ) {
1184 if (auth) {
1185 lt6_tmp.ia6t_vltime = new->ndpr_vltime;
1186 }
1187 } else {
1188 /*
1189 * new->ndpr_vltime <= TWOHOUR &&
1190 * TWOHOUR < storedlifetime
1191 */
1192 lt6_tmp.ia6t_vltime = TWOHOUR;
1193 }
1194
1195 /* The 2 hour rule is not imposed for preferred lifetime. */
1196 lt6_tmp.ia6t_pltime = new->ndpr_pltime;
1197
1198 in6_init_address_ltimes(pr, <6_tmp);
1199
1200 ifa6->ia6_lifetime = lt6_tmp;
1201 ifa6->ia6_updatetime = time.tv_sec;
1202 }
1203 if (ia6_match == NULL && new->ndpr_vltime) {
1204 /*
1205 * No address matched and the valid lifetime is non-zero.
1206 * Create a new address.
1207 */
1208 if ((ia6 = in6_ifadd(new)) != NULL) {
1209 /*
1210 * note that we should use pr (not new) for reference.
1211 */
1212 pr->ndpr_refcnt++;
1213 ia6->ia6_ndpr = pr;
1214
1215 /*
1216 * A newly added address might affect the status
1217 * of other addresses, so we check and update it.
1218 * XXX: what if address duplication happens?
1219 */
1220 pfxlist_onlink_check();
1221 } else {
1222 /* just set an error. do not bark here. */
1223 error = EADDRNOTAVAIL; /* XXX: might be unused. */
1224 }
1225 }
1226
1227 end:
1228 splx(s);
1229 return error;
1230 }
1231
1232 /*
1233 * A supplement function used in the on-link detection below;
1234 * detect if a given prefix has a (probably) reachable advertising router.
1235 * XXX: lengthy function name...
1236 */
1237 static struct nd_pfxrouter *
find_pfxlist_reachable_router(pr)1238 find_pfxlist_reachable_router(pr)
1239 struct nd_prefix *pr;
1240 {
1241 struct nd_pfxrouter *pfxrtr;
1242 struct rtentry *rt;
1243 struct llinfo_nd6 *ln;
1244
1245 for (pfxrtr = LIST_FIRST(&pr->ndpr_advrtrs); pfxrtr;
1246 pfxrtr = LIST_NEXT(pfxrtr, pfr_entry)) {
1247 if ((rt = nd6_lookup(&pfxrtr->router->rtaddr, 0,
1248 pfxrtr->router->ifp)) &&
1249 (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
1250 ND6_IS_LLINFO_PROBREACH(ln))
1251 break; /* found */
1252 }
1253
1254 return (pfxrtr);
1255 }
1256
1257 /*
1258 * Check if each prefix in the prefix list has at least one available router
1259 * that advertised the prefix (a router is "available" if its neighbor cache
1260 * entry is reachable or probably reachable).
1261 * If the check fails, the prefix may be off-link, because, for example,
1262 * we have moved from the network but the lifetime of the prefix has not
1263 * expired yet. So we should not use the prefix if there is another prefix
1264 * that has an available router.
1265 * But, if there is no prefix that has an available router, we still regards
1266 * all the prefixes as on-link. This is because we can't tell if all the
1267 * routers are simply dead or if we really moved from the network and there
1268 * is no router around us.
1269 */
1270 void
pfxlist_onlink_check()1271 pfxlist_onlink_check()
1272 {
1273 struct nd_prefix *pr;
1274 struct in6_ifaddr *ifa;
1275
1276 /*
1277 * Check if there is a prefix that has a reachable advertising
1278 * router.
1279 */
1280 for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
1281 if (pr->ndpr_raf_onlink && find_pfxlist_reachable_router(pr))
1282 break;
1283 }
1284 if (pr != NULL || TAILQ_FIRST(&nd_defrouter) != NULL) {
1285 /*
1286 * There is at least one prefix that has a reachable router,
1287 * or at least a router which probably does not advertise
1288 * any prefixes. The latter would be the case when we move
1289 * to a new link where we have a router that does not provide
1290 * prefixes and we configure an address by hand.
1291 * Detach prefixes which have no reachable advertising
1292 * router, and attach other prefixes.
1293 */
1294 for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
1295 /* XXX: a link-local prefix should never be detached */
1296 if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
1297 continue;
1298
1299 /*
1300 * we aren't interested in prefixes without the L bit
1301 * set.
1302 */
1303 if (pr->ndpr_raf_onlink == 0)
1304 continue;
1305
1306 if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
1307 find_pfxlist_reachable_router(pr) == NULL)
1308 pr->ndpr_stateflags |= NDPRF_DETACHED;
1309 if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
1310 find_pfxlist_reachable_router(pr) != 0)
1311 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
1312 }
1313 } else {
1314 /* there is no prefix that has a reachable router */
1315 for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
1316 if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
1317 continue;
1318
1319 if (pr->ndpr_raf_onlink == 0)
1320 continue;
1321
1322 if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0)
1323 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
1324 }
1325 }
1326
1327 /*
1328 * Remove each interface route associated with a (just) detached
1329 * prefix, and reinstall the interface route for a (just) attached
1330 * prefix. Note that all attempt of reinstallation does not
1331 * necessarily success, when a same prefix is shared among multiple
1332 * interfaces. Such cases will be handled in nd6_prefix_onlink,
1333 * so we don't have to care about them.
1334 */
1335 for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
1336 int e;
1337
1338 if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
1339 continue;
1340
1341 if (pr->ndpr_raf_onlink == 0)
1342 continue;
1343
1344 if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
1345 (pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
1346 if ((e = nd6_prefix_offlink(pr)) != 0) {
1347 nd6log((LOG_ERR,
1348 "pfxlist_onlink_check: failed to "
1349 "make %s/%d offlink, errno=%d\n",
1350 ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
1351 pr->ndpr_plen, e));
1352 }
1353 }
1354 if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
1355 (pr->ndpr_stateflags & NDPRF_ONLINK) == 0 &&
1356 pr->ndpr_raf_onlink) {
1357 if ((e = nd6_prefix_onlink(pr)) != 0) {
1358 nd6log((LOG_ERR,
1359 "pfxlist_onlink_check: failed to "
1360 "make %s/%d offlink, errno=%d\n",
1361 ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
1362 pr->ndpr_plen, e));
1363 }
1364 }
1365 }
1366
1367 /*
1368 * Changes on the prefix status might affect address status as well.
1369 * Make sure that all addresses derived from an attached prefix are
1370 * attached, and that all addresses derived from a detached prefix are
1371 * detached. Note, however, that a manually configured address should
1372 * always be attached.
1373 * The precise detection logic is same as the one for prefixes.
1374 */
1375 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
1376 if (!(ifa->ia6_flags & IN6_IFF_AUTOCONF))
1377 continue;
1378
1379 if (ifa->ia6_ndpr == NULL) {
1380 /*
1381 * This can happen when we first configure the address
1382 * (i.e. the address exists, but the prefix does not).
1383 * XXX: complicated relationships...
1384 */
1385 continue;
1386 }
1387
1388 if (find_pfxlist_reachable_router(ifa->ia6_ndpr))
1389 break;
1390 }
1391 if (ifa) {
1392 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
1393 if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
1394 continue;
1395
1396 if (ifa->ia6_ndpr == NULL) /* XXX: see above. */
1397 continue;
1398
1399 if (find_pfxlist_reachable_router(ifa->ia6_ndpr))
1400 ifa->ia6_flags &= ~IN6_IFF_DETACHED;
1401 else
1402 ifa->ia6_flags |= IN6_IFF_DETACHED;
1403 }
1404 }
1405 else {
1406 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
1407 if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
1408 continue;
1409
1410 ifa->ia6_flags &= ~IN6_IFF_DETACHED;
1411 }
1412 }
1413 }
1414
1415 int
nd6_prefix_onlink(pr)1416 nd6_prefix_onlink(pr)
1417 struct nd_prefix *pr;
1418 {
1419 struct ifaddr *ifa;
1420 struct ifnet *ifp = pr->ndpr_ifp;
1421 struct sockaddr_in6 mask6;
1422 struct nd_prefix *opr;
1423 u_long rtflags;
1424 int error = 0;
1425 struct rtentry *rt = NULL;
1426
1427 /* sanity check */
1428 if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
1429 nd6log((LOG_ERR,
1430 "nd6_prefix_onlink: %s/%d is already on-link\n",
1431 ip6_sprintf(&pr->ndpr_prefix.sin6_addr), pr->ndpr_plen));
1432 return (EEXIST);
1433 }
1434
1435 /*
1436 * Add the interface route associated with the prefix. Before
1437 * installing the route, check if there's the same prefix on another
1438 * interface, and the prefix has already installed the interface route.
1439 * Although such a configuration is expected to be rare, we explicitly
1440 * allow it.
1441 */
1442 for (opr = nd_prefix.lh_first; opr; opr = opr->ndpr_next) {
1443 if (opr == pr)
1444 continue;
1445
1446 if ((opr->ndpr_stateflags & NDPRF_ONLINK) == 0)
1447 continue;
1448
1449 if (opr->ndpr_plen == pr->ndpr_plen &&
1450 in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
1451 &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen))
1452 return (0);
1453 }
1454
1455 /*
1456 * We prefer link-local addresses as the associated interface address.
1457 */
1458 /* search for a link-local addr */
1459 ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
1460 IN6_IFF_NOTREADY | IN6_IFF_ANYCAST);
1461 if (ifa == NULL) {
1462 /* XXX: freebsd does not have ifa_ifwithaf */
1463 for (ifa = ifp->if_addrlist.tqh_first;
1464 ifa;
1465 ifa = ifa->ifa_list.tqe_next)
1466 {
1467 if (ifa->ifa_addr->sa_family == AF_INET6)
1468 break;
1469 }
1470 /* should we care about ia6_flags? */
1471 }
1472 if (ifa == NULL) {
1473 /*
1474 * This can still happen, when, for example, we receive an RA
1475 * containing a prefix with the L bit set and the A bit clear,
1476 * after removing all IPv6 addresses on the receiving
1477 * interface. This should, of course, be rare though.
1478 */
1479 nd6log((LOG_NOTICE,
1480 "nd6_prefix_onlink: failed to find any ifaddr"
1481 " to add route for a prefix(%s/%d) on %s\n",
1482 ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
1483 pr->ndpr_plen, ifp->if_xname));
1484 return (0);
1485 }
1486
1487 /*
1488 * in6_ifinit() sets nd6_rtrequest to ifa_rtrequest for all ifaddrs.
1489 * ifa->ifa_rtrequest = nd6_rtrequest;
1490 */
1491 bzero(&mask6, sizeof(mask6));
1492 mask6.sin6_len = sizeof(mask6);
1493 mask6.sin6_addr = pr->ndpr_mask;
1494 /* rtrequest() will probably set RTF_UP, but we're not sure. */
1495 rtflags = ifa->ifa_flags | RTF_UP;
1496 if (nd6_need_cache(ifp)) {
1497 /* explicitly set in case ifa_flags does not set the flag. */
1498 rtflags |= RTF_CLONING;
1499 } else {
1500 /*
1501 * explicitly clear the cloning bit in case ifa_flags sets it.
1502 */
1503 rtflags &= ~RTF_CLONING;
1504 }
1505 error = rtrequest(RTM_ADD, (struct sockaddr *)&pr->ndpr_prefix,
1506 ifa->ifa_addr, (struct sockaddr *)&mask6, rtflags, &rt);
1507 if (error == 0) {
1508 if (rt != NULL) /* this should be non NULL, though */
1509 nd6_rtmsg(RTM_ADD, rt);
1510 pr->ndpr_stateflags |= NDPRF_ONLINK;
1511 } else {
1512 nd6log((LOG_ERR, "nd6_prefix_onlink: failed to add route for a"
1513 " prefix (%s/%d) on %s, gw=%s, mask=%s, flags=%lx "
1514 "errno = %d\n",
1515 ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
1516 pr->ndpr_plen, ifp->if_xname,
1517 ip6_sprintf(&((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr),
1518 ip6_sprintf(&mask6.sin6_addr), rtflags, error));
1519 }
1520
1521 if (rt != NULL)
1522 rt->rt_refcnt--;
1523
1524 return (error);
1525 }
1526
1527 int
nd6_prefix_offlink(pr)1528 nd6_prefix_offlink(pr)
1529 struct nd_prefix *pr;
1530 {
1531 int error = 0;
1532 struct ifnet *ifp = pr->ndpr_ifp;
1533 struct nd_prefix *opr;
1534 struct sockaddr_in6 sa6, mask6;
1535 struct rtentry *rt = NULL;
1536
1537 /* sanity check */
1538 if ((pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
1539 nd6log((LOG_ERR,
1540 "nd6_prefix_offlink: %s/%d is already off-link\n",
1541 ip6_sprintf(&pr->ndpr_prefix.sin6_addr), pr->ndpr_plen));
1542 return (EEXIST);
1543 }
1544
1545 bzero(&sa6, sizeof(sa6));
1546 sa6.sin6_family = AF_INET6;
1547 sa6.sin6_len = sizeof(sa6);
1548 bcopy(&pr->ndpr_prefix.sin6_addr, &sa6.sin6_addr,
1549 sizeof(struct in6_addr));
1550 bzero(&mask6, sizeof(mask6));
1551 mask6.sin6_family = AF_INET6;
1552 mask6.sin6_len = sizeof(sa6);
1553 bcopy(&pr->ndpr_mask, &mask6.sin6_addr, sizeof(struct in6_addr));
1554 error = rtrequest(RTM_DELETE, (struct sockaddr *)&sa6, NULL,
1555 (struct sockaddr *)&mask6, 0, &rt);
1556 if (error == 0) {
1557 pr->ndpr_stateflags &= ~NDPRF_ONLINK;
1558
1559 /* report the route deletion to the routing socket. */
1560 if (rt != NULL)
1561 nd6_rtmsg(RTM_DELETE, rt);
1562
1563 /*
1564 * There might be the same prefix on another interface,
1565 * the prefix which could not be on-link just because we have
1566 * the interface route (see comments in nd6_prefix_onlink).
1567 * If there's one, try to make the prefix on-link on the
1568 * interface.
1569 */
1570 for (opr = nd_prefix.lh_first; opr; opr = opr->ndpr_next) {
1571 if (opr == pr)
1572 continue;
1573
1574 if ((opr->ndpr_stateflags & NDPRF_ONLINK) != 0)
1575 continue;
1576
1577 /*
1578 * KAME specific: detached prefixes should not be
1579 * on-link.
1580 */
1581 if ((opr->ndpr_stateflags & NDPRF_DETACHED) != 0)
1582 continue;
1583
1584 if (opr->ndpr_plen == pr->ndpr_plen &&
1585 in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
1586 &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
1587 int e;
1588
1589 if ((e = nd6_prefix_onlink(opr)) != 0) {
1590 nd6log((LOG_ERR,
1591 "nd6_prefix_offlink: failed to "
1592 "recover a prefix %s/%d from %s "
1593 "to %s (errno = %d)\n",
1594 ip6_sprintf(&opr->ndpr_prefix.sin6_addr),
1595 opr->ndpr_plen, ifp->if_xname,
1596 opr->ndpr_ifp->if_xname, e));
1597 }
1598 }
1599 }
1600 } else {
1601 /* XXX: can we still set the NDPRF_ONLINK flag? */
1602 nd6log((LOG_ERR,
1603 "nd6_prefix_offlink: failed to delete route: "
1604 "%s/%d on %s (errno = %d)\n",
1605 ip6_sprintf(&sa6.sin6_addr), pr->ndpr_plen, ifp->if_xname,
1606 error));
1607 }
1608
1609 if (rt != NULL) {
1610 if (rt->rt_refcnt <= 0) {
1611 /* XXX: we should free the entry ourselves. */
1612 rt->rt_refcnt++;
1613 rtfree(rt);
1614 }
1615 }
1616
1617 return (error);
1618 }
1619
1620 static struct in6_ifaddr *
in6_ifadd(pr)1621 in6_ifadd(pr)
1622 struct nd_prefix *pr;
1623 {
1624 struct ifnet *ifp = pr->ndpr_ifp;
1625 struct ifaddr *ifa;
1626 struct in6_aliasreq ifra;
1627 struct in6_ifaddr *ia, *ib;
1628 int error, plen0;
1629 struct in6_addr mask;
1630 int prefixlen = pr->ndpr_plen;
1631
1632 in6_prefixlen2mask(&mask, prefixlen);
1633
1634 /*
1635 * find a link-local address (will be interface ID).
1636 * Is it really mandatory? Theoretically, a global or a site-local
1637 * address can be configured without a link-local address, if we
1638 * have a unique interface identifier...
1639 *
1640 * it is not mandatory to have a link-local address, we can generate
1641 * interface identifier on the fly. we do this because:
1642 * (1) it should be the easiest way to find interface identifier.
1643 * (2) RFC2462 5.4 suggesting the use of the same interface identifier
1644 * for multiple addresses on a single interface, and possible shortcut
1645 * of DAD. we omitted DAD for this reason in the past.
1646 * (3) a user can prevent autoconfiguration of global address
1647 * by removing link-local address by hand (this is partly because we
1648 * don't have other way to control the use of IPv6 on a interface.
1649 * this has been our design choice - cf. NRL's "ifconfig auto").
1650 * (4) it is easier to manage when an interface has addresses
1651 * with the same interface identifier, than to have multiple addresses
1652 * with different interface identifiers.
1653 */
1654 ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp, 0); /* 0 is OK? */
1655 if (ifa)
1656 ib = (struct in6_ifaddr *)ifa;
1657 else
1658 return NULL;
1659
1660 #if 0 /* don't care link local addr state, and always do DAD */
1661 /* if link-local address is not eligible, do not autoconfigure. */
1662 if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_NOTREADY) {
1663 printf("in6_ifadd: link-local address not ready\n");
1664 return NULL;
1665 }
1666 #endif
1667
1668 /* prefixlen + ifidlen must be equal to 128 */
1669 plen0 = in6_mask2len(&ib->ia_prefixmask.sin6_addr, NULL);
1670 if (prefixlen != plen0) {
1671 nd6log((LOG_INFO, "in6_ifadd: wrong prefixlen for %s "
1672 "(prefix=%d ifid=%d)\n",
1673 ifp->if_xname, prefixlen, 128 - plen0));
1674 return NULL;
1675 }
1676
1677 /* make ifaddr */
1678
1679 bzero(&ifra, sizeof(ifra));
1680 /*
1681 * in6_update_ifa() does not use ifra_name, but we accurately set it
1682 * for safety.
1683 */
1684 strncpy(ifra.ifra_name, ifp->if_xname, sizeof(ifra.ifra_name));
1685 ifra.ifra_addr.sin6_family = AF_INET6;
1686 ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
1687 /* prefix */
1688 bcopy(&pr->ndpr_prefix.sin6_addr, &ifra.ifra_addr.sin6_addr,
1689 sizeof(ifra.ifra_addr.sin6_addr));
1690 ifra.ifra_addr.sin6_addr.s6_addr32[0] &= mask.s6_addr32[0];
1691 ifra.ifra_addr.sin6_addr.s6_addr32[1] &= mask.s6_addr32[1];
1692 ifra.ifra_addr.sin6_addr.s6_addr32[2] &= mask.s6_addr32[2];
1693 ifra.ifra_addr.sin6_addr.s6_addr32[3] &= mask.s6_addr32[3];
1694
1695 /* interface ID */
1696 ifra.ifra_addr.sin6_addr.s6_addr32[0] |=
1697 (ib->ia_addr.sin6_addr.s6_addr32[0] & ~mask.s6_addr32[0]);
1698 ifra.ifra_addr.sin6_addr.s6_addr32[1] |=
1699 (ib->ia_addr.sin6_addr.s6_addr32[1] & ~mask.s6_addr32[1]);
1700 ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
1701 (ib->ia_addr.sin6_addr.s6_addr32[2] & ~mask.s6_addr32[2]);
1702 ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
1703 (ib->ia_addr.sin6_addr.s6_addr32[3] & ~mask.s6_addr32[3]);
1704
1705 /* new prefix mask. */
1706 ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
1707 ifra.ifra_prefixmask.sin6_family = AF_INET6;
1708 bcopy(&mask, &ifra.ifra_prefixmask.sin6_addr,
1709 sizeof(ifra.ifra_prefixmask.sin6_addr));
1710
1711 /*
1712 * lifetime.
1713 * XXX: in6_init_address_ltimes would override these values later.
1714 * We should reconsider this logic.
1715 */
1716 ifra.ifra_lifetime.ia6t_vltime = pr->ndpr_vltime;
1717 ifra.ifra_lifetime.ia6t_pltime = pr->ndpr_pltime;
1718
1719 /* XXX: scope zone ID? */
1720
1721 ifra.ifra_flags |= IN6_IFF_AUTOCONF; /* obey autoconf */
1722
1723 /* allocate ifaddr structure, link into chain, etc. */
1724 if ((error = in6_update_ifa(ifp, &ifra, NULL)) != 0) {
1725 nd6log((LOG_ERR,
1726 "in6_ifadd: failed to make ifaddr %s on %s (errno=%d)\n",
1727 ip6_sprintf(&ifra.ifra_addr.sin6_addr), ifp->if_xname,
1728 error));
1729 return (NULL); /* ifaddr must not have been allocated. */
1730 }
1731
1732 ia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
1733
1734 return (ia); /* this is always non-NULL */
1735 }
1736
1737 int
in6_init_prefix_ltimes(struct nd_prefix * ndpr)1738 in6_init_prefix_ltimes(struct nd_prefix *ndpr)
1739 {
1740
1741 /* check if preferred lifetime > valid lifetime. RFC2462 5.5.3 (c) */
1742 if (ndpr->ndpr_pltime > ndpr->ndpr_vltime) {
1743 nd6log((LOG_INFO, "in6_init_prefix_ltimes: preferred lifetime"
1744 "(%d) is greater than valid lifetime(%d)\n",
1745 (u_int)ndpr->ndpr_pltime, (u_int)ndpr->ndpr_vltime));
1746 return (EINVAL);
1747 }
1748 if (ndpr->ndpr_pltime == ND6_INFINITE_LIFETIME)
1749 ndpr->ndpr_preferred = 0;
1750 else
1751 ndpr->ndpr_preferred = time.tv_sec + ndpr->ndpr_pltime;
1752 if (ndpr->ndpr_vltime == ND6_INFINITE_LIFETIME)
1753 ndpr->ndpr_expire = 0;
1754 else
1755 ndpr->ndpr_expire = time.tv_sec + ndpr->ndpr_vltime;
1756
1757 return 0;
1758 }
1759
1760 static void
in6_init_address_ltimes(struct nd_prefix * new,struct in6_addrlifetime * lt6)1761 in6_init_address_ltimes(struct nd_prefix *new, struct in6_addrlifetime *lt6)
1762 {
1763
1764 /* Valid lifetime must not be updated unless explicitly specified. */
1765 /* init ia6t_expire */
1766 if (lt6->ia6t_vltime == ND6_INFINITE_LIFETIME)
1767 lt6->ia6t_expire = 0;
1768 else {
1769 lt6->ia6t_expire = time.tv_sec;
1770 lt6->ia6t_expire += lt6->ia6t_vltime;
1771 }
1772
1773 /* init ia6t_preferred */
1774 if (lt6->ia6t_pltime == ND6_INFINITE_LIFETIME)
1775 lt6->ia6t_preferred = 0;
1776 else {
1777 lt6->ia6t_preferred = time.tv_sec;
1778 lt6->ia6t_preferred += lt6->ia6t_pltime;
1779 }
1780 }
1781
1782 /*
1783 * Delete all the routing table entries that use the specified gateway.
1784 * XXX: this function causes search through all entries of routing table, so
1785 * it shouldn't be called when acting as a router.
1786 */
1787 void
rt6_flush(gateway,ifp)1788 rt6_flush(gateway, ifp)
1789 struct in6_addr *gateway;
1790 struct ifnet *ifp;
1791 {
1792 struct radix_node_head *rnh = rt_tables[AF_INET6];
1793 int s = splsoftnet();
1794
1795 /* We'll care only link-local addresses */
1796 if (!IN6_IS_ADDR_LINKLOCAL(gateway)) {
1797 splx(s);
1798 return;
1799 }
1800 /* XXX: hack for KAME's link-local address kludge */
1801 gateway->s6_addr16[1] = htons(ifp->if_index);
1802
1803 rnh->rnh_walktree(rnh, rt6_deleteroute, (void *)gateway);
1804 splx(s);
1805 }
1806
1807 static int
rt6_deleteroute(rn,arg)1808 rt6_deleteroute(rn, arg)
1809 struct radix_node *rn;
1810 void *arg;
1811 {
1812 #define SIN6(s) ((struct sockaddr_in6 *)s)
1813 struct rtentry *rt = (struct rtentry *)rn;
1814 struct in6_addr *gate = (struct in6_addr *)arg;
1815
1816 if (rt->rt_gateway == NULL || rt->rt_gateway->sa_family != AF_INET6)
1817 return (0);
1818
1819 if (!IN6_ARE_ADDR_EQUAL(gate, &SIN6(rt->rt_gateway)->sin6_addr))
1820 return (0);
1821
1822 /*
1823 * Do not delete a static route.
1824 * XXX: this seems to be a bit ad-hoc. Should we consider the
1825 * 'cloned' bit instead?
1826 */
1827 if ((rt->rt_flags & RTF_STATIC) != 0)
1828 return (0);
1829
1830 /*
1831 * We delete only host route. This means, in particular, we don't
1832 * delete default route.
1833 */
1834 if ((rt->rt_flags & RTF_HOST) == 0)
1835 return (0);
1836
1837 return (rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
1838 rt_mask(rt), rt->rt_flags, 0));
1839 #undef SIN6
1840 }
1841
1842 int
nd6_setdefaultiface(ifindex)1843 nd6_setdefaultiface(ifindex)
1844 int ifindex;
1845 {
1846 int error = 0;
1847
1848 if (ifindex < 0 || if_indexlim <= ifindex)
1849 return (EINVAL);
1850 if (ifindex != 0 && !ifindex2ifnet[ifindex])
1851 return (EINVAL);
1852
1853 if (nd6_defifindex != ifindex) {
1854 nd6_defifindex = ifindex;
1855 if (nd6_defifindex > 0) {
1856 nd6_defifp = ifindex2ifnet[nd6_defifindex];
1857 } else
1858 nd6_defifp = NULL;
1859 }
1860
1861 return (error);
1862 }
1863