xref: /openbsd/sys/netinet6/nd6_rtr.c (revision 74ae6390)
1 /*	$OpenBSD: nd6_rtr.c,v 1.144 2016/09/02 11:51:07 florian 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/timeout.h>
36 #include <sys/malloc.h>
37 #include <sys/mbuf.h>
38 #include <sys/socket.h>
39 #include <sys/sockio.h>
40 #include <sys/time.h>
41 #include <sys/kernel.h>
42 #include <sys/errno.h>
43 #include <sys/ioctl.h>
44 #include <sys/syslog.h>
45 #include <sys/queue.h>
46 
47 #include <net/if.h>
48 #include <net/if_dl.h>
49 #include <net/if_var.h>
50 #include <net/route.h>
51 #include <net/rtable.h>
52 
53 #include <netinet/in.h>
54 #include <netinet6/in6_var.h>
55 #include <netinet/ip6.h>
56 #include <netinet6/ip6_var.h>
57 #include <netinet6/nd6.h>
58 #include <netinet/icmp6.h>
59 
60 int rtpref(struct nd_defrouter *);
61 struct nd_defrouter *defrtrlist_update(struct nd_defrouter *);
62 struct in6_ifaddr *in6_ifadd(struct nd_prefix *, int);
63 struct nd_pfxrouter *pfxrtr_lookup(struct nd_prefix *, struct nd_defrouter *);
64 void pfxrtr_add(struct nd_prefix *, struct nd_defrouter *);
65 void pfxrtr_del(struct nd_pfxrouter *);
66 struct nd_pfxrouter *find_pfxlist_reachable_router(struct nd_prefix *);
67 void defrouter_delreq(struct nd_defrouter *);
68 void purge_detached(struct ifnet *);
69 int nd6_prefix_onlink(struct nd_prefix *);
70 int nd6_prefix_offlink(struct nd_prefix *);
71 void in6_init_address_ltimes(struct nd_prefix *, struct in6_addrlifetime *);
72 
73 int rt6_deleteroute(struct rtentry *, void *, unsigned int);
74 
75 void nd6_addr_add(void *);
76 
77 void nd6_rs_output_timo(void *);
78 u_int32_t nd6_rs_next_pltime_timo(struct ifnet *);
79 void nd6_rs_output_set_timo(int);
80 void nd6_rs_output(struct ifnet *, struct in6_ifaddr *);
81 void nd6_rs_dev_state(void *);
82 
83 extern int nd6_recalc_reachtm_interval;
84 
85 #define ND6_RS_OUTPUT_INTERVAL		60
86 #define ND6_RS_OUTPUT_QUICK_INTERVAL	1
87 
88 struct timeout	nd6_rs_output_timer;
89 int		nd6_rs_output_timeout = ND6_RS_OUTPUT_INTERVAL;
90 int		nd6_rs_timeout_count = 0;
91 
92 void
93 nd6_rs_init(void)
94 {
95 	timeout_set(&nd6_rs_output_timer, nd6_rs_output_timo, NULL);
96 }
97 
98 
99 /*
100  * Receive Router Solicitation Message - just for routers.
101  * Router solicitation/advertisement is mostly managed by userland program
102  * (rtadvd) so here we have no function like nd6_ra_output().
103  *
104  * Based on RFC 2461
105  */
106 void
107 nd6_rs_input(struct mbuf *m, int off, int icmp6len)
108 {
109 	struct ifnet *ifp;
110 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
111 	struct nd_router_solicit *nd_rs;
112 	struct in6_addr saddr6 = ip6->ip6_src;
113 #if 0
114 	struct in6_addr daddr6 = ip6->ip6_dst;
115 #endif
116 	char *lladdr = NULL;
117 	int lladdrlen = 0;
118 #if 0
119 	struct sockaddr_dl *sdl = NULL;
120 	struct llinfo_nd6 *ln = NULL;
121 	struct rtentry *rt = NULL;
122 	int is_newentry;
123 #endif
124 	union nd_opts ndopts;
125 	char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN];
126 
127 	/* If I'm not a router, ignore it. XXX - too restrictive? */
128 	if (!ip6_forwarding)
129 		goto freeit;
130 
131 	/* Sanity checks */
132 	if (ip6->ip6_hlim != 255) {
133 		nd6log((LOG_ERR,
134 		    "nd6_rs_input: invalid hlim (%d) from %s to %s on %u\n",
135 		    ip6->ip6_hlim,
136 		    inet_ntop(AF_INET6, &ip6->ip6_src, src, sizeof(src)),
137 		    inet_ntop(AF_INET6, &ip6->ip6_dst, dst, sizeof(dst)),
138 		    m->m_pkthdr.ph_ifidx));
139 		goto bad;
140 	}
141 
142 	/*
143 	 * Don't update the neighbor cache, if src = ::.
144 	 * This indicates that the src has no IP address assigned yet.
145 	 */
146 	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
147 		goto freeit;
148 
149 	IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off, icmp6len);
150 	if (nd_rs == NULL) {
151 		icmp6stat.icp6s_tooshort++;
152 		return;
153 	}
154 
155 	icmp6len -= sizeof(*nd_rs);
156 	nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
157 	if (nd6_options(&ndopts) < 0) {
158 		nd6log((LOG_INFO,
159 		    "nd6_rs_input: invalid ND option, ignored\n"));
160 		/* nd6_options have incremented stats */
161 		goto freeit;
162 	}
163 
164 	if (ndopts.nd_opts_src_lladdr) {
165 		lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
166 		lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
167 	}
168 
169 	ifp = if_get(m->m_pkthdr.ph_ifidx);
170 	if (ifp == NULL)
171 		goto freeit;
172 
173 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
174 		nd6log((LOG_INFO,
175 		    "nd6_rs_input: lladdrlen mismatch for %s "
176 		    "(if %d, RS packet %d)\n",
177 		    inet_ntop(AF_INET6, &saddr6, src, sizeof(src)),
178 		    ifp->if_addrlen, lladdrlen - 2));
179 		if_put(ifp);
180 		goto bad;
181 	}
182 
183 	nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_SOLICIT, 0);
184 	if_put(ifp);
185 
186  freeit:
187 	m_freem(m);
188 	return;
189 
190  bad:
191 	icmp6stat.icp6s_badrs++;
192 	m_freem(m);
193 }
194 
195 void
196 nd6_rs_output(struct ifnet* ifp, struct in6_ifaddr *ia6)
197 {
198 	struct mbuf *m;
199 	struct ip6_hdr *ip6;
200 	struct nd_router_solicit *rs;
201 	struct ip6_moptions im6o;
202 	caddr_t mac;
203 	int icmp6len, maxlen, s;
204 
205 	KASSERT(ia6 != NULL);
206 	KASSERT(ifp->if_flags & IFF_RUNNING);
207 	KASSERT(ifp->if_xflags & IFXF_AUTOCONF6);
208 	KASSERT(!(ia6->ia6_flags & IN6_IFF_TENTATIVE));
209 
210 	maxlen = sizeof(*ip6) + sizeof(*rs);
211 	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
212 
213 	MGETHDR(m, M_DONTWAIT, MT_DATA);
214 	if (m && max_linkhdr + maxlen >= MHLEN) {
215 		MCLGET(m, M_DONTWAIT);
216 		if ((m->m_flags & M_EXT) == 0) {
217 			m_free(m);
218 			m = NULL;
219 		}
220 	}
221 	if (m == NULL)
222 		return;
223 
224 	m->m_pkthdr.ph_ifidx = 0;
225 	m->m_pkthdr.ph_rtableid = ifp->if_rdomain;
226 	m->m_flags |= M_MCAST;
227 	m->m_pkthdr.csum_flags |= M_ICMP_CSUM_OUT;
228 
229 	im6o.im6o_ifidx = ifp->if_index;
230 	im6o.im6o_hlim = 255;
231 	im6o.im6o_loop = 0;
232 
233 	icmp6len = sizeof(*rs);
234 	m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
235 	m->m_data += max_linkhdr;	/* or MH_ALIGN() equivalent? */
236 
237 	/* fill neighbor solicitation packet */
238 	ip6 = mtod(m, struct ip6_hdr *);
239 	ip6->ip6_flow = 0;
240 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
241 	ip6->ip6_vfc |= IPV6_VERSION;
242 	/* ip6->ip6_plen will be set later */
243 	ip6->ip6_nxt = IPPROTO_ICMPV6;
244 	ip6->ip6_hlim = 255;
245 
246 	ip6->ip6_dst = in6addr_linklocal_allrouters;
247 
248 	ip6->ip6_src = ia6->ia_addr.sin6_addr;
249 
250 	rs = (struct nd_router_solicit *)(ip6 + 1);
251 	rs->nd_rs_type = ND_ROUTER_SOLICIT;
252 	rs->nd_rs_code = 0;
253 	rs->nd_rs_cksum = 0;
254 	rs->nd_rs_reserved = 0;
255 
256 	if ((mac = nd6_ifptomac(ifp))) {
257 		int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
258 		struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(rs + 1);
259 		/* 8 byte alignments... */
260 		optlen = (optlen + 7) & ~7;
261 
262 		m->m_pkthdr.len += optlen;
263 		m->m_len += optlen;
264 		icmp6len += optlen;
265 		bzero((caddr_t)nd_opt, optlen);
266 		nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
267 		nd_opt->nd_opt_len = optlen >> 3;
268 		bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
269 	}
270 
271 	ip6->ip6_plen = htons((u_short)icmp6len);
272 
273 	s = splsoftnet();
274 	ip6_output(m, NULL, NULL, 0, &im6o, NULL);
275 	splx(s);
276 
277 	icmp6stat.icp6s_outhist[ND_ROUTER_SOLICIT]++;
278 }
279 
280 void
281 nd6_rs_output_set_timo(int timeout)
282 {
283 	nd6_rs_output_timeout = timeout;
284 	timeout_add_sec(&nd6_rs_output_timer, nd6_rs_output_timeout);
285 }
286 
287 u_int32_t
288 nd6_rs_next_pltime_timo(struct ifnet *ifp)
289 {
290 	struct ifaddr *ifa;
291 	struct in6_ifaddr *ia6;
292 	u_int32_t pltime_expires = ND6_INFINITE_LIFETIME;
293 
294 	TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
295 		if (ifa->ifa_addr->sa_family != AF_INET6)
296 			continue;
297 
298 		ia6 = ifatoia6(ifa);
299 		if (ia6->ia6_lifetime.ia6t_pltime == ND6_INFINITE_LIFETIME ||
300 		    IFA6_IS_DEPRECATED(ia6) || IFA6_IS_INVALID(ia6))
301 			continue;
302 
303 		pltime_expires = MIN(pltime_expires,
304 		    ia6->ia6_lifetime.ia6t_pltime);
305 	}
306 
307 	return pltime_expires;
308 }
309 
310 void
311 nd6_rs_output_timo(void *ignored_arg)
312 {
313 	struct ifnet *ifp;
314 	struct in6_ifaddr *ia6;
315 	u_int32_t pltime_expire = ND6_INFINITE_LIFETIME, t;
316 	int timeout = ND6_RS_OUTPUT_INTERVAL;
317 
318 	if (nd6_rs_timeout_count == 0)
319 		return;
320 
321 	if (nd6_rs_output_timeout < ND6_RS_OUTPUT_INTERVAL)
322 		/* exponential backoff if running quick timeouts */
323 		timeout = nd6_rs_output_timeout * 2;
324 
325 	TAILQ_FOREACH(ifp, &ifnet, if_list) {
326 		if (ISSET(ifp->if_flags, IFF_RUNNING) &&
327 		    ISSET(ifp->if_xflags, IFXF_AUTOCONF6)) {
328 			t = nd6_rs_next_pltime_timo(ifp);
329 			if (t == ND6_INFINITE_LIFETIME || t <
330 			    ND6_RS_OUTPUT_INTERVAL) {
331 				timeout = ND6_RS_OUTPUT_QUICK_INTERVAL;
332 				ia6 = in6ifa_ifpforlinklocal(ifp,
333 				    IN6_IFF_TENTATIVE);
334 				if (ia6 != NULL)
335 					nd6_rs_output(ifp, ia6);
336 			}
337 
338 			pltime_expire = MIN(pltime_expire, t);
339 		}
340 	}
341 	if (pltime_expire != ND6_INFINITE_LIFETIME)
342 		timeout = MAX(timeout, pltime_expire / 2);
343 
344 	nd6_rs_output_set_timo(timeout);
345 }
346 
347 void
348 nd6_rs_attach(struct ifnet *ifp)
349 {
350 	if (!ISSET(ifp->if_xflags, IFXF_AUTOCONF6)) {
351 		/*
352 		 * We are being called from net/if.c, autoconf is not yet
353 		 * enabled on the interface.
354 		 */
355 		nd6_rs_timeout_count++;
356 		RS_LHCOOKIE(ifp) = hook_establish(ifp->if_linkstatehooks, 1,
357 		    nd6_rs_dev_state, ifp);
358 	}
359 
360 	/*
361 	 * (re)send solicitation regardless if we are enableing autoconf
362 	 * for the first time or if the link comes up
363 	 */
364 	nd6_rs_output_set_timo(ND6_RS_OUTPUT_QUICK_INTERVAL);
365 }
366 
367 void
368 nd6_rs_detach(struct ifnet *ifp)
369 {
370 	if (ISSET(ifp->if_xflags, IFXF_AUTOCONF6)) {
371 		nd6_rs_timeout_count--;
372 		hook_disestablish(ifp->if_linkstatehooks, RS_LHCOOKIE(ifp));
373 	}
374 
375 	if (nd6_rs_timeout_count == 0)
376 		timeout_del(&nd6_rs_output_timer);
377 }
378 
379 void
380 nd6_rs_dev_state(void *arg)
381 {
382 	struct ifnet *ifp;
383 
384 	ifp = (struct ifnet *) arg;
385 
386 	if (LINK_STATE_IS_UP(ifp->if_link_state) &&
387 	    ifp->if_flags & IFF_RUNNING)
388 		/* start quick timer, will exponentially back off */
389 		nd6_rs_output_set_timo(ND6_RS_OUTPUT_QUICK_INTERVAL);
390 }
391 
392 /*
393  * Receive Router Advertisement Message.
394  *
395  * Based on RFC 2461
396  */
397 void
398 nd6_ra_input(struct mbuf *m, int off, int icmp6len)
399 {
400 	struct ifnet *ifp;
401 	struct nd_ifinfo *ndi;
402 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
403 	struct nd_router_advert *nd_ra;
404 	struct in6_addr saddr6 = ip6->ip6_src;
405 	union nd_opts ndopts;
406 	struct nd_defrouter *dr;
407 	char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN];
408 
409 	ifp = if_get(m->m_pkthdr.ph_ifidx);
410 	if (ifp == NULL)
411 		goto freeit;
412 
413 	/* We accept RAs only if inet6 autoconf is enabled  */
414 	if (!(ifp->if_xflags & IFXF_AUTOCONF6))
415 		goto freeit;
416 
417 	ndi = ND_IFINFO(ifp);
418 	if (!(ndi->flags & ND6_IFF_ACCEPT_RTADV))
419 		goto freeit;
420 
421 	if (nd6_rs_output_timeout != ND6_RS_OUTPUT_INTERVAL)
422 		/* we saw a RA, stop quick timer */
423 		nd6_rs_output_set_timo(ND6_RS_OUTPUT_INTERVAL);
424 
425 	if (ip6->ip6_hlim != 255) {
426 		nd6log((LOG_ERR,
427 		    "nd6_ra_input: invalid hlim (%d) from %s to %s on %s\n",
428 		    ip6->ip6_hlim,
429 		    inet_ntop(AF_INET6, &ip6->ip6_src, src, sizeof(src)),
430 		    inet_ntop(AF_INET6, &ip6->ip6_dst, dst, sizeof(dst)),
431 		    ifp->if_xname));
432 		goto bad;
433 	}
434 
435 	if (!IN6_IS_ADDR_LINKLOCAL(&saddr6)) {
436 		nd6log((LOG_ERR,
437 		    "nd6_ra_input: src %s is not link-local\n",
438 		    inet_ntop(AF_INET6, &saddr6, src, sizeof(src))));
439 		goto bad;
440 	}
441 
442 	IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off, icmp6len);
443 	if (nd_ra == NULL) {
444 		icmp6stat.icp6s_tooshort++;
445 		if_put(ifp);
446 		return;
447 	}
448 
449 	icmp6len -= sizeof(*nd_ra);
450 	nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
451 	if (nd6_options(&ndopts) < 0) {
452 		nd6log((LOG_INFO,
453 		    "nd6_ra_input: invalid ND option, ignored\n"));
454 		/* nd6_options have incremented stats */
455 		goto freeit;
456 	}
457 
458     {
459 	struct nd_defrouter dr0;
460 	u_int32_t advreachable = nd_ra->nd_ra_reachable;
461 
462 	memset(&dr0, 0, sizeof(dr0));
463 	dr0.rtaddr = saddr6;
464 	dr0.flags  = nd_ra->nd_ra_flags_reserved;
465 	dr0.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);
466 	dr0.expire = time_second + dr0.rtlifetime;
467 	dr0.ifp = ifp;
468 	/* unspecified or not? (RFC 2461 6.3.4) */
469 	if (advreachable) {
470 		advreachable = ntohl(advreachable);
471 		if (advreachable <= MAX_REACHABLE_TIME &&
472 		    ndi->basereachable != advreachable) {
473 			ndi->basereachable = advreachable;
474 			ndi->reachable = ND_COMPUTE_RTIME(ndi->basereachable);
475 			ndi->recalctm = nd6_recalc_reachtm_interval; /* reset */
476 		}
477 	}
478 	if (nd_ra->nd_ra_retransmit)
479 		ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
480 	if (nd_ra->nd_ra_curhoplimit) {
481 		/*
482 		 * Ignore it.  The router doesn't know the diameter of
483 		 * the Internet better than this source code.
484 		 */
485 	}
486 	dr = defrtrlist_update(&dr0);
487     }
488 
489 	/*
490 	 * prefix
491 	 */
492 	if (ndopts.nd_opts_pi) {
493 		struct nd_opt_hdr *pt;
494 		struct nd_opt_prefix_info *pi = NULL;
495 		struct nd_prefix pr;
496 
497 		for (pt = (struct nd_opt_hdr *)ndopts.nd_opts_pi;
498 		     pt <= (struct nd_opt_hdr *)ndopts.nd_opts_pi_end;
499 		     pt = (struct nd_opt_hdr *)((caddr_t)pt +
500 						(pt->nd_opt_len << 3))) {
501 			if (pt->nd_opt_type != ND_OPT_PREFIX_INFORMATION)
502 				continue;
503 			pi = (struct nd_opt_prefix_info *)pt;
504 
505 			if (pi->nd_opt_pi_len != 4) {
506 				nd6log((LOG_INFO,
507 				    "nd6_ra_input: invalid option "
508 				    "len %d for prefix information option, "
509 				    "ignored\n", pi->nd_opt_pi_len));
510 				continue;
511 			}
512 
513 			if (128 < pi->nd_opt_pi_prefix_len) {
514 				nd6log((LOG_INFO,
515 				    "nd6_ra_input: invalid prefix "
516 				    "len %d for prefix information option, "
517 				    "ignored\n", pi->nd_opt_pi_prefix_len));
518 				continue;
519 			}
520 
521 			if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix)
522 			 || IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix)) {
523 				nd6log((LOG_INFO,
524 				    "nd6_ra_input: invalid prefix "
525 				    "%s, ignored\n",
526 				    inet_ntop(AF_INET6, &pi->nd_opt_pi_prefix,
527 					src, sizeof(src))));
528 				continue;
529 			}
530 
531 			/* aggregatable unicast address, rfc2374 */
532 			if ((pi->nd_opt_pi_prefix.s6_addr8[0] & 0xe0) == 0x20
533 			 && pi->nd_opt_pi_prefix_len != 64) {
534 				nd6log((LOG_INFO,
535 				    "nd6_ra_input: invalid prefixlen "
536 				    "%d for rfc2374 prefix %s, ignored\n",
537 				    pi->nd_opt_pi_prefix_len,
538 				    inet_ntop(AF_INET6, &pi->nd_opt_pi_prefix,
539 					src, sizeof(src))));
540 				continue;
541 			}
542 
543 			bzero(&pr, sizeof(pr));
544 			pr.ndpr_prefix.sin6_family = AF_INET6;
545 			pr.ndpr_prefix.sin6_len = sizeof(pr.ndpr_prefix);
546 			pr.ndpr_prefix.sin6_addr = pi->nd_opt_pi_prefix;
547 			pr.ndpr_ifp = ifp;
548 
549 			pr.ndpr_raf_onlink = (pi->nd_opt_pi_flags_reserved &
550 			     ND_OPT_PI_FLAG_ONLINK) ? 1 : 0;
551 			pr.ndpr_raf_auto = (pi->nd_opt_pi_flags_reserved &
552 			     ND_OPT_PI_FLAG_AUTO) ? 1 : 0;
553 			pr.ndpr_plen = pi->nd_opt_pi_prefix_len;
554 			pr.ndpr_vltime = ntohl(pi->nd_opt_pi_valid_time);
555 			pr.ndpr_pltime = ntohl(pi->nd_opt_pi_preferred_time);
556 			pr.ndpr_lastupdate = time_second;
557 
558 			if (in6_init_prefix_ltimes(&pr))
559 				continue; /* prefix lifetime init failed */
560 
561 			(void)prelist_update(&pr, dr, m);
562 		}
563 	}
564 
565 	/*
566 	 * Source link layer address
567 	 */
568     {
569 	char *lladdr = NULL;
570 	int lladdrlen = 0;
571 
572 	if (ndopts.nd_opts_src_lladdr) {
573 		lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
574 		lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
575 	}
576 
577 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
578 		nd6log((LOG_INFO,
579 		    "nd6_ra_input: lladdrlen mismatch for %s "
580 		    "(if %d, RA packet %d)\n",
581 		    inet_ntop(AF_INET6, &saddr6, src, sizeof(src)),
582 		    ifp->if_addrlen, lladdrlen - 2));
583 		goto bad;
584 	}
585 
586 	nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_ADVERT, 0);
587 
588 	/*
589 	 * Installing a link-layer address might change the state of the
590 	 * router's neighbor cache, which might also affect our on-link
591 	 * detection of advertised prefixes.
592 	 */
593 	pfxlist_onlink_check();
594     }
595 
596  freeit:
597 	if_put(ifp);
598 	m_freem(m);
599 	return;
600 
601  bad:
602 	icmp6stat.icp6s_badra++;
603 	if_put(ifp);
604 	m_freem(m);
605 }
606 
607 /*
608  * default router list processing sub routines
609  */
610 void
611 defrouter_addreq(struct nd_defrouter *new)
612 {
613 	struct rt_addrinfo info;
614 	struct sockaddr_in6 def, mask, gate;
615 	struct rtentry *rt;
616 	int s;
617 	int error;
618 
619 	memset(&def, 0, sizeof(def));
620 	memset(&mask, 0, sizeof(mask));
621 	memset(&gate, 0, sizeof(gate)); /* for safety */
622 	memset(&info, 0, sizeof(info));
623 
624 	def.sin6_len = mask.sin6_len = gate.sin6_len =
625 	    sizeof(struct sockaddr_in6);
626 	def.sin6_family = mask.sin6_family = gate.sin6_family = AF_INET6;
627 	gate.sin6_addr = new->rtaddr;
628 	gate.sin6_scope_id = 0;	/* XXX */
629 
630 	info.rti_flags = RTF_GATEWAY;
631 	info.rti_info[RTAX_DST] = sin6tosa(&def);
632 	info.rti_info[RTAX_GATEWAY] = sin6tosa(&gate);
633 	info.rti_info[RTAX_NETMASK] = sin6tosa(&mask);
634 
635 	s = splsoftnet();
636 	error = rtrequest(RTM_ADD, &info, RTP_DEFAULT, &rt,
637 	    new->ifp->if_rdomain);
638 	if (error == 0) {
639 		rt_sendmsg(rt, RTM_ADD, new->ifp->if_rdomain);
640 		rtfree(rt);
641 		new->installed = 1;
642 	}
643 	splx(s);
644 	return;
645 }
646 
647 struct nd_defrouter *
648 defrouter_lookup(struct in6_addr *addr, unsigned int ifidx)
649 {
650 	struct nd_defrouter *dr;
651 
652 	TAILQ_FOREACH(dr, &nd_defrouter, dr_entry)
653 		if (dr->ifp->if_index == ifidx &&
654 		    IN6_ARE_ADDR_EQUAL(addr, &dr->rtaddr))
655 			return (dr);
656 
657 	return (NULL);		/* search failed */
658 }
659 
660 void
661 defrtrlist_del(struct nd_defrouter *dr)
662 {
663 	struct nd_defrouter *deldr = NULL;
664 	struct in6_ifextra *ext = dr->ifp->if_afdata[AF_INET6];
665 	struct nd_prefix *pr;
666 
667 	/*
668 	 * Flush all the routing table entries that use the router
669 	 * as a next hop.
670 	 */
671 	/* XXX: better condition? */
672 	if (!ip6_forwarding)
673 		rt6_flush(&dr->rtaddr, dr->ifp);
674 
675 	if (dr->installed) {
676 		deldr = dr;
677 		defrouter_delreq(dr);
678 	}
679 	TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
680 
681 	/*
682 	 * Also delete all the pointers to the router in each prefix lists.
683 	 */
684 	LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
685 		struct nd_pfxrouter *pfxrtr;
686 		if ((pfxrtr = pfxrtr_lookup(pr, dr)) != NULL)
687 			pfxrtr_del(pfxrtr);
688 	}
689 	pfxlist_onlink_check();
690 
691 	/*
692 	 * If the router is the primary one, choose a new one.
693 	 * Note that defrouter_select() will remove the current gateway
694 	 * from the routing table.
695 	 */
696 	if (deldr)
697 		defrouter_select();
698 
699 	ext->ndefrouters--;
700 	if (ext->ndefrouters < 0) {
701 		log(LOG_WARNING, "defrtrlist_del: negative count on %s\n",
702 		    dr->ifp->if_xname);
703 	}
704 
705 	free(dr, M_IP6NDP, sizeof(*dr));
706 }
707 
708 /*
709  * Remove the default route for a given router.
710  * This is just a subroutine function for defrouter_select(), and should
711  * not be called from anywhere else.
712  */
713 void
714 defrouter_delreq(struct nd_defrouter *dr)
715 {
716 	struct rt_addrinfo info;
717 	struct sockaddr_in6 def, mask, gw;
718 	struct rtentry *rt;
719 	int error;
720 
721 #ifdef DIAGNOSTIC
722 	if (!dr)
723 		panic("dr == NULL in defrouter_delreq");
724 #endif
725 
726 	memset(&info, 0, sizeof(info));
727 	memset(&def, 0, sizeof(def));
728 	memset(&mask, 0, sizeof(mask));
729 	memset(&gw, 0, sizeof(gw));	/* for safety */
730 
731 	def.sin6_len = mask.sin6_len = gw.sin6_len =
732 	    sizeof(struct sockaddr_in6);
733 	def.sin6_family = mask.sin6_family = gw.sin6_family = AF_INET6;
734 	gw.sin6_addr = dr->rtaddr;
735 	gw.sin6_scope_id = 0;	/* XXX */
736 
737 	info.rti_flags = RTF_GATEWAY;
738 	info.rti_info[RTAX_DST] = sin6tosa(&def);
739 	info.rti_info[RTAX_GATEWAY] = sin6tosa(&gw);
740 	info.rti_info[RTAX_NETMASK] = sin6tosa(&mask);
741 
742 	error = rtrequest(RTM_DELETE, &info, RTP_DEFAULT, &rt,
743 	    dr->ifp->if_rdomain);
744 	if (error == 0) {
745 		rt_sendmsg(rt, RTM_DELETE, dr->ifp->if_rdomain);
746 		rtfree(rt);
747 	}
748 
749 	dr->installed = 0;
750 }
751 
752 /*
753  * remove all default routes from default router list
754  */
755 void
756 defrouter_reset(void)
757 {
758 	struct nd_defrouter *dr;
759 
760 	TAILQ_FOREACH(dr, &nd_defrouter, dr_entry)
761 		defrouter_delreq(dr);
762 
763 	/*
764 	 * XXX should we also nuke any default routers in the kernel, by
765 	 * going through them by rtalloc()?
766 	 */
767 }
768 
769 /*
770  * Default Router Selection according to Section 6.3.6 of RFC 2461 and
771  * draft-ietf-ipngwg-router-selection:
772  * 1) Routers that are reachable or probably reachable should be preferred.
773  *    If we have more than one (probably) reachable router, prefer ones
774  *    with the highest router preference.
775  * 2) When no routers on the list are known to be reachable or
776  *    probably reachable, routers SHOULD be selected in a round-robin
777  *    fashion, regardless of router preference values.
778  * 3) If the Default Router List is empty, assume that all
779  *    destinations are on-link.
780  *
781  * We assume nd_defrouter is sorted by router preference value.
782  * Since the code below covers both with and without router preference cases,
783  * we do not need to classify the cases by ifdef.
784  *
785  * At this moment, we do not try to install more than one default router,
786  * even when the multipath routing is available, because we're not sure about
787  * the benefits for stub hosts comparing to the risk of making the code
788  * complicated and the possibility of introducing bugs.
789  */
790 void
791 defrouter_select(void)
792 {
793 	struct nd_defrouter *dr, *selected_dr = NULL, *installed_dr = NULL;
794 	struct rtentry *rt = NULL;
795 	struct llinfo_nd6 *ln = NULL;
796 	int s = splsoftnet();
797 
798 	/*
799 	 * Let's handle easy case (3) first:
800 	 * If default router list is empty, there's nothing to be done.
801 	 */
802 	if (TAILQ_EMPTY(&nd_defrouter)) {
803 		splx(s);
804 		return;
805 	}
806 
807 	/*
808 	 * Search for a (probably) reachable router from the list.
809 	 * We just pick up the first reachable one (if any), assuming that
810 	 * the ordering rule of the list described in defrtrlist_update().
811 	 */
812 	TAILQ_FOREACH(dr, &nd_defrouter, dr_entry) {
813 		if (!(dr->ifp->if_xflags & IFXF_AUTOCONF6))
814 			continue;
815 		if (!selected_dr) {
816 			rt = nd6_lookup(&dr->rtaddr, 0, dr->ifp,
817 			    dr->ifp->if_rdomain);
818 			if ((rt != NULL) &&
819 			    (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
820 			    ND6_IS_LLINFO_PROBREACH(ln)) {
821 				selected_dr = dr;
822 			}
823 			rtfree(rt);
824 		}
825 
826 		if (dr->installed && !installed_dr)
827 			installed_dr = dr;
828 		else if (dr->installed && installed_dr) {
829 			/* this should not happen.  warn for diagnosis. */
830 			log(LOG_ERR, "defrouter_select: more than one router"
831 			    " is installed\n");
832 		}
833 	}
834 	/*
835 	 * If none of the default routers was found to be reachable,
836 	 * round-robin the list regardless of preference.
837 	 * Otherwise, if we have an installed router, check if the selected
838 	 * (reachable) router should really be preferred to the installed one.
839 	 * We only prefer the new router when the old one is not reachable
840 	 * or when the new one has a really higher preference value.
841 	 */
842 	if (!selected_dr) {
843 		if (!installed_dr || !TAILQ_NEXT(installed_dr, dr_entry))
844 			selected_dr = TAILQ_FIRST(&nd_defrouter);
845 		else
846 			selected_dr = TAILQ_NEXT(installed_dr, dr_entry);
847 	} else if (installed_dr) {
848 		rt = nd6_lookup(&installed_dr->rtaddr, 0, installed_dr->ifp,
849 		    installed_dr->ifp->if_rdomain);
850 		if ((rt != NULL) && (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
851 		    ND6_IS_LLINFO_PROBREACH(ln) &&
852 		    rtpref(selected_dr) <= rtpref(installed_dr)) {
853 			selected_dr = installed_dr;
854 		}
855 		rtfree(rt);
856 	}
857 
858 	/*
859 	 * If the selected router is different than the installed one,
860 	 * remove the installed router and install the selected one.
861 	 * Note that the selected router is never NULL here.
862 	 */
863 	if (installed_dr != selected_dr) {
864 		if (installed_dr)
865 			defrouter_delreq(installed_dr);
866 		defrouter_addreq(selected_dr);
867 	}
868 
869 	splx(s);
870 	return;
871 }
872 
873 /*
874  * for default router selection
875  * regards router-preference field as a 2-bit signed integer
876  */
877 int
878 rtpref(struct nd_defrouter *dr)
879 {
880 #ifdef RTPREF
881 	switch (dr->flags & ND_RA_FLAG_RTPREF_MASK) {
882 	case ND_RA_FLAG_RTPREF_HIGH:
883 		return RTPREF_HIGH;
884 	case ND_RA_FLAG_RTPREF_MEDIUM:
885 	case ND_RA_FLAG_RTPREF_RSV:
886 		return RTPREF_MEDIUM;
887 	case ND_RA_FLAG_RTPREF_LOW:
888 		return RTPREF_LOW;
889 	default:
890 		/*
891 		 * This case should never happen.  If it did, it would mean a
892 		 * serious bug of kernel internal.  We thus always bark here.
893 		 * Or, can we even panic?
894 		 */
895 		log(LOG_ERR, "rtpref: impossible RA flag %x", dr->flags);
896 		return RTPREF_INVALID;
897 	}
898 	/* NOTREACHED */
899 #else
900 	return 0;
901 #endif
902 }
903 
904 struct nd_defrouter *
905 defrtrlist_update(struct nd_defrouter *new)
906 {
907 	struct nd_defrouter *dr, *n;
908 	struct in6_ifextra *ext = new->ifp->if_afdata[AF_INET6];
909 	int s = splsoftnet();
910 
911 	if ((dr = defrouter_lookup(&new->rtaddr, new->ifp->if_index)) != NULL) {
912 		/* entry exists */
913 		if (new->rtlifetime == 0) {
914 			defrtrlist_del(dr);
915 			dr = NULL;
916 		} else {
917 			int oldpref = rtpref(dr);
918 
919 			/* override */
920 			dr->flags = new->flags; /* xxx flag check */
921 			dr->rtlifetime = new->rtlifetime;
922 			dr->expire = new->expire;
923 
924 			if (!dr->installed)
925 				defrouter_select();
926 
927 			/*
928 			 * If the preference does not change, there's no need
929 			 * to sort the entries.
930 			 */
931 			if (rtpref(new) == oldpref) {
932 				splx(s);
933 				return (dr);
934 			}
935 
936 			/*
937 			 * preferred router may be changed, so relocate
938 			 * this router.
939 			 * XXX: calling TAILQ_REMOVE directly is a bad manner.
940 			 * However, since defrtrlist_del() has many side
941 			 * effects, we intentionally do so here.
942 			 * defrouter_select() below will handle routing
943 			 * changes later.
944 			 */
945 			TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
946 			n = dr;
947 			goto insert;
948 		}
949 		splx(s);
950 		return (dr);
951 	}
952 
953 	/* entry does not exist */
954 	if (new->rtlifetime == 0) {
955 		/* flush all possible redirects */
956 		if (new->ifp->if_xflags & IFXF_AUTOCONF6)
957 			rt6_flush(&new->rtaddr, new->ifp);
958 		splx(s);
959 		return (NULL);
960 	}
961 
962 	if (ip6_maxifdefrouters >= 0 &&
963 	    ext->ndefrouters >= ip6_maxifdefrouters) {
964 		splx(s);
965 		return (NULL);
966 	}
967 
968 	n = malloc(sizeof(*n), M_IP6NDP, M_NOWAIT | M_ZERO);
969 	if (n == NULL) {
970 		splx(s);
971 		return (NULL);
972 	}
973 	*n = *new;
974 
975 insert:
976 	/*
977 	 * Insert the new router in the Default Router List;
978 	 * The Default Router List should be in the descending order
979 	 * of router-preference.  Routers with the same preference are
980 	 * sorted in the arriving time order.
981 	 */
982 
983 	/* insert at the end of the group */
984 	TAILQ_FOREACH(dr, &nd_defrouter, dr_entry)
985 		if (rtpref(n) > rtpref(dr))
986 			break;
987 	if (dr)
988 		TAILQ_INSERT_BEFORE(dr, n, dr_entry);
989 	else
990 		TAILQ_INSERT_TAIL(&nd_defrouter, n, dr_entry);
991 
992 	defrouter_select();
993 
994 	ext->ndefrouters++;
995 
996 	splx(s);
997 
998 	return (n);
999 }
1000 
1001 struct nd_pfxrouter *
1002 pfxrtr_lookup(struct nd_prefix *pr, struct nd_defrouter *dr)
1003 {
1004 	struct nd_pfxrouter *search;
1005 
1006 	LIST_FOREACH(search, &pr->ndpr_advrtrs, pfr_entry) {
1007 		if (search->router == dr)
1008 			break;
1009 	}
1010 
1011 	return (search);
1012 }
1013 
1014 void
1015 pfxrtr_add(struct nd_prefix *pr, struct nd_defrouter *dr)
1016 {
1017 	struct nd_pfxrouter *new;
1018 
1019 	new = malloc(sizeof(*new), M_IP6NDP, M_NOWAIT | M_ZERO);
1020 	if (new == NULL)
1021 		return;
1022 	new->router = dr;
1023 
1024 	LIST_INSERT_HEAD(&pr->ndpr_advrtrs, new, pfr_entry);
1025 
1026 	pfxlist_onlink_check();
1027 }
1028 
1029 void
1030 pfxrtr_del(struct nd_pfxrouter *pfr)
1031 {
1032 	LIST_REMOVE(pfr, pfr_entry);
1033 	free(pfr, M_IP6NDP, sizeof(*pfr));
1034 }
1035 
1036 struct nd_prefix *
1037 nd6_prefix_lookup(struct nd_prefix *pr)
1038 {
1039 	struct nd_prefix *search;
1040 
1041 	LIST_FOREACH(search, &nd_prefix, ndpr_entry) {
1042 		if (pr->ndpr_ifp == search->ndpr_ifp &&
1043 		    pr->ndpr_plen == search->ndpr_plen &&
1044 		    in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
1045 		    &search->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
1046 			break;
1047 		}
1048 	}
1049 
1050 	return (search);
1051 }
1052 
1053 void
1054 purge_detached(struct ifnet *ifp)
1055 {
1056 	struct nd_prefix *pr, *pr_next;
1057 	struct in6_ifaddr *ia6;
1058 	struct ifaddr *ifa, *ifa_next;
1059 
1060 	splsoftassert(IPL_SOFTNET);
1061 
1062 	LIST_FOREACH_SAFE(pr, &nd_prefix, ndpr_entry, pr_next) {
1063 		/*
1064 		 * This function is called when we need to make more room for
1065 		 * new prefixes rather than keeping old, possibly stale ones.
1066 		 * Detached prefixes would be a good candidate; if all routers
1067 		 * that advertised the prefix expired, the prefix is also
1068 		 * probably stale.
1069 		 */
1070 		if (pr->ndpr_ifp != ifp ||
1071 		    IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr) ||
1072 		    ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
1073 		    !LIST_EMPTY(&pr->ndpr_advrtrs)))
1074 			continue;
1075 
1076 		TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrlist, ifa_list, ifa_next) {
1077 			if (ifa->ifa_addr->sa_family != AF_INET6)
1078 				continue;
1079 			ia6 = ifatoia6(ifa);
1080 			if ((ia6->ia6_flags & IN6_IFF_AUTOCONF) ==
1081 			    IN6_IFF_AUTOCONF && ia6->ia6_ndpr == pr) {
1082 				in6_purgeaddr(ifa);
1083 			}
1084 		}
1085 	}
1086 }
1087 
1088 int
1089 nd6_prelist_add(struct nd_prefix *pr, struct nd_defrouter *dr,
1090     struct nd_prefix **newp)
1091 {
1092 	struct nd_prefix *new = NULL;
1093 	int i, s;
1094 	struct in6_ifextra *ext = pr->ndpr_ifp->if_afdata[AF_INET6];
1095 
1096 	if (ip6_maxifprefixes >= 0) {
1097 		if (ext->nprefixes >= ip6_maxifprefixes / 2) {
1098 			s = splsoftnet();
1099 			purge_detached(pr->ndpr_ifp);
1100 			splx(s);
1101 		}
1102 		if (ext->nprefixes >= ip6_maxifprefixes)
1103 			return(ENOMEM);
1104 	}
1105 
1106 	new = malloc(sizeof(*new), M_IP6NDP, M_NOWAIT | M_ZERO);
1107 	if (new == NULL)
1108 		return ENOMEM;
1109 	*new = *pr;
1110 	if (newp != NULL)
1111 		*newp = new;
1112 
1113 	/* initialization */
1114 	LIST_INIT(&new->ndpr_advrtrs);
1115 	in6_prefixlen2mask(&new->ndpr_mask, new->ndpr_plen);
1116 	/* make prefix in the canonical form */
1117 	for (i = 0; i < 4; i++)
1118 		new->ndpr_prefix.sin6_addr.s6_addr32[i] &=
1119 		    new->ndpr_mask.s6_addr32[i];
1120 
1121 	task_set(&new->ndpr_task, nd6_addr_add, new);
1122 
1123 	s = splsoftnet();
1124 	/* link ndpr_entry to nd_prefix list */
1125 	LIST_INSERT_HEAD(&nd_prefix, new, ndpr_entry);
1126 
1127 	/* ND_OPT_PI_FLAG_ONLINK processing */
1128 	if (new->ndpr_raf_onlink) {
1129 		char addr[INET6_ADDRSTRLEN];
1130 		int e;
1131 
1132 		if ((e = nd6_prefix_onlink(new)) != 0) {
1133 			nd6log((LOG_ERR, "nd6_prelist_add: failed to make "
1134 			    "the prefix %s/%d on-link on %s (errno=%d)\n",
1135 			    inet_ntop(AF_INET6, &pr->ndpr_prefix.sin6_addr,
1136 				addr, sizeof(addr)),
1137 			    pr->ndpr_plen, pr->ndpr_ifp->if_xname, e));
1138 			/* proceed anyway. XXX: is it correct? */
1139 		}
1140 	}
1141 
1142 	if (dr)
1143 		pfxrtr_add(new, dr);
1144 	splx(s);
1145 
1146 	ext->nprefixes++;
1147 
1148 	return 0;
1149 }
1150 
1151 void
1152 prelist_remove(struct nd_prefix *pr)
1153 {
1154 	struct nd_pfxrouter *pfr, *next;
1155 	int e, s;
1156 	struct in6_ifextra *ext = pr->ndpr_ifp->if_afdata[AF_INET6];
1157 
1158 	/* make sure to invalidate the prefix until it is really freed. */
1159 	pr->ndpr_vltime = 0;
1160 	pr->ndpr_pltime = 0;
1161 
1162 	if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0 &&
1163 	    (e = nd6_prefix_offlink(pr)) != 0) {
1164 		char addr[INET6_ADDRSTRLEN];
1165 		nd6log((LOG_ERR, "prelist_remove: failed to make %s/%d offlink "
1166 		    "on %s, errno=%d\n",
1167 		    inet_ntop(AF_INET6, &pr->ndpr_prefix.sin6_addr,
1168 			addr, sizeof(addr)),
1169 		    pr->ndpr_plen, pr->ndpr_ifp->if_xname, e));
1170 		/* what should we do? */
1171 	}
1172 
1173 	if (pr->ndpr_refcnt > 0)
1174 		return;		/* notice here? */
1175 
1176 	s = splsoftnet();
1177 
1178 	/* unlink ndpr_entry from nd_prefix list */
1179 	LIST_REMOVE(pr, ndpr_entry);
1180 
1181 	/* free list of routers that adversed the prefix */
1182 	LIST_FOREACH_SAFE(pfr, &pr->ndpr_advrtrs, pfr_entry, next)
1183 		free(pfr, M_IP6NDP, sizeof(*pfr));
1184 
1185 	ext->nprefixes--;
1186 	if (ext->nprefixes < 0) {
1187 		log(LOG_WARNING, "prelist_remove: negative count on %s\n",
1188 		    pr->ndpr_ifp->if_xname);
1189 	}
1190 
1191 	free(pr, M_IP6NDP, sizeof(*pr));
1192 
1193 	pfxlist_onlink_check();
1194 	splx(s);
1195 }
1196 
1197 /*
1198  * dr - may be NULL
1199  */
1200 
1201 int
1202 prelist_update(struct nd_prefix *new, struct nd_defrouter *dr, struct mbuf *m)
1203 {
1204 	struct in6_ifaddr *ia6_match = NULL;
1205 	struct ifaddr *ifa;
1206 	struct ifnet *ifp = new->ndpr_ifp;
1207 	struct nd_prefix *pr;
1208 	int s, error = 0;
1209 	int tempaddr_preferred = 0, autoconf = 0, statique = 0;
1210 	int auth;
1211 	struct in6_addrlifetime lt6_tmp;
1212 	char addr[INET6_ADDRSTRLEN];
1213 
1214 	s = splsoftnet();
1215 
1216 	auth = 0;
1217 	if (m) {
1218 		/*
1219 		 * Authenticity for NA consists authentication for
1220 		 * both IP header and IP datagrams, doesn't it ?
1221 		 */
1222 		auth = (m->m_flags & M_AUTH);
1223 	}
1224 
1225 	if ((pr = nd6_prefix_lookup(new)) != NULL) {
1226 		/*
1227 		 * nd6_prefix_lookup() ensures that pr and new have the same
1228 		 * prefix on a same interface.
1229 		 */
1230 
1231 		/*
1232 		 * Update prefix information.  Note that the on-link (L) bit
1233 		 * and the autonomous (A) bit should NOT be changed from 1
1234 		 * to 0.
1235 		 */
1236 		if (new->ndpr_raf_onlink == 1)
1237 			pr->ndpr_raf_onlink = 1;
1238 		if (new->ndpr_raf_auto == 1)
1239 			pr->ndpr_raf_auto = 1;
1240 		if (new->ndpr_raf_onlink) {
1241 			pr->ndpr_vltime = new->ndpr_vltime;
1242 			pr->ndpr_pltime = new->ndpr_pltime;
1243 			pr->ndpr_preferred = new->ndpr_preferred;
1244 			pr->ndpr_expire = new->ndpr_expire;
1245 			pr->ndpr_lastupdate = new->ndpr_lastupdate;
1246 		}
1247 
1248 		if (new->ndpr_raf_onlink &&
1249 		    (pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
1250 			int e;
1251 
1252 			if ((e = nd6_prefix_onlink(pr)) != 0) {
1253 				nd6log((LOG_ERR,
1254 				    "prelist_update: failed to make "
1255 				    "the prefix %s/%d on-link on %s "
1256 				    "(errno=%d)\n",
1257 				    inet_ntop(AF_INET6,
1258 					&pr->ndpr_prefix.sin6_addr,
1259 					addr, sizeof(addr)),
1260 				    pr->ndpr_plen, pr->ndpr_ifp->if_xname, e));
1261 				/* proceed anyway. XXX: is it correct? */
1262 			}
1263 		}
1264 
1265 		if (dr && pfxrtr_lookup(pr, dr) == NULL)
1266 			pfxrtr_add(pr, dr);
1267 	} else {
1268 		struct nd_prefix *newpr = NULL;
1269 
1270 		if (new->ndpr_vltime == 0)
1271 			goto end;
1272 		if (new->ndpr_raf_onlink == 0 && new->ndpr_raf_auto == 0)
1273 			goto end;
1274 
1275 		error = nd6_prelist_add(new, dr, &newpr);
1276 		if (error != 0 || newpr == NULL) {
1277 			nd6log((LOG_NOTICE, "prelist_update: "
1278 			    "nd6_prelist_add failed for %s/%d on %s "
1279 			    "errno=%d, returnpr=%p\n",
1280 			    inet_ntop(AF_INET6, &new->ndpr_prefix.sin6_addr,
1281 				addr, sizeof(addr)),
1282 			    new->ndpr_plen, new->ndpr_ifp->if_xname,
1283 			    error, newpr));
1284 			goto end; /* we should just give up in this case. */
1285 		}
1286 
1287 		pr = newpr;
1288 	}
1289 
1290 	/*
1291 	 * Address autoconfiguration based on Section 5.5.3 of RFC 2462.
1292 	 * Note that pr must be non NULL at this point.
1293 	 */
1294 
1295 	/* 5.5.3 (a). Ignore the prefix without the A bit set. */
1296 	if (!new->ndpr_raf_auto)
1297 		goto end;
1298 
1299 	/*
1300 	 * 5.5.3 (b). the link-local prefix should have been ignored in
1301 	 * nd6_ra_input.
1302 	 */
1303 
1304 	/*
1305 	 * 5.5.3 (c). Consistency check on lifetimes: pltime <= vltime.
1306 	 * This should have been done in nd6_ra_input.
1307 	 */
1308 
1309 	/*
1310 	 * 5.5.3 (d). If the prefix advertised does not match the prefix of an
1311 	 * address already in the list, and the Valid Lifetime is not 0,
1312 	 * form an address.  Note that even a manually configured address
1313 	 * should reject autoconfiguration of a new address.
1314 	 */
1315 	TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
1316 		struct in6_ifaddr *ia6;
1317 		int ifa_plen;
1318 		u_int32_t storedlifetime;
1319 
1320 		if (ifa->ifa_addr->sa_family != AF_INET6)
1321 			continue;
1322 
1323 		ia6 = ifatoia6(ifa);
1324 
1325 		/*
1326 		 * Spec is not clear here, but I believe we should concentrate
1327 		 * on unicast (i.e. not anycast) addresses.
1328 		 * XXX: other ia6_flags? detached or duplicated?
1329 		 */
1330 		if ((ia6->ia6_flags & IN6_IFF_ANYCAST) != 0)
1331 			continue;
1332 
1333 		ifa_plen = in6_mask2len(&ia6->ia_prefixmask.sin6_addr, NULL);
1334 		if (ifa_plen != new->ndpr_plen ||
1335 		    !in6_are_prefix_equal(&ia6->ia_addr.sin6_addr,
1336 		    &new->ndpr_prefix.sin6_addr, ifa_plen))
1337 			continue;
1338 
1339 		if (ia6_match == NULL) /* remember the first one */
1340 			ia6_match = ia6;
1341 
1342 		if ((ia6->ia6_flags & IN6_IFF_AUTOCONF) == 0) {
1343 			statique = 1;
1344 			continue;
1345 		}
1346 
1347 		/*
1348 		 * An already autoconfigured address matched.  Now that we
1349 		 * are sure there is at least one matched address, we can
1350 		 * proceed to 5.5.3. (e): update the lifetimes according to the
1351 		 * "two hours" rule and the privacy extension.
1352 		 */
1353 #define TWOHOUR		(120*60)
1354 		/*
1355 		 * RFC2462 introduces the notion of StoredLifetime to the
1356 		 * "two hours" rule as follows:
1357 		 *   the Lifetime associated with the previously autoconfigured
1358 		 *   address.
1359 		 * Our interpretation of this definition is "the remaining
1360 		 * lifetime to expiration at the evaluation time".  One might
1361 		 * be wondering if this interpretation is really conform to the
1362 		 * RFC, because the text can read that "Lifetimes" are never
1363 		 * decreased, and our definition of the "storedlifetime" below
1364 		 * essentially reduces the "Valid Lifetime" advertised in the
1365 		 * previous RA.  But, this is due to the wording of the text,
1366 		 * and our interpretation is the same as an author's intention.
1367 		 * See the discussion in the IETF ipngwg ML in August 2001,
1368 		 * with the Subject "StoredLifetime in RFC 2462".
1369 		 */
1370 		lt6_tmp = ia6->ia6_lifetime;
1371 
1372 		/* RFC 4941 temporary addresses (privacy extension). */
1373 		if (ia6->ia6_flags & IN6_IFF_PRIVACY) {
1374 			/* Do we still have a non-deprecated address? */
1375 			if ((ia6->ia6_flags & IN6_IFF_DEPRECATED) == 0)
1376 				tempaddr_preferred = 1;
1377 			/* Don't extend lifetime for temporary addresses. */
1378 			if (new->ndpr_vltime >= lt6_tmp.ia6t_vltime)
1379 				continue;
1380 			if (new->ndpr_pltime >= lt6_tmp.ia6t_pltime)
1381 				continue;
1382 		} else if ((ia6->ia6_flags & IN6_IFF_DEPRECATED) == 0)
1383 			/* We have a regular SLAAC address. */
1384 			autoconf = 1;
1385 
1386 		if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME)
1387 			storedlifetime = ND6_INFINITE_LIFETIME;
1388 		else if (time_second - ia6->ia6_updatetime >
1389 			 lt6_tmp.ia6t_vltime) {
1390 			/*
1391 			 * The case of "invalid" address.  We should usually
1392 			 * not see this case.
1393 			 */
1394 			storedlifetime = 0;
1395 		} else
1396 			storedlifetime = lt6_tmp.ia6t_vltime -
1397 				(time_second - ia6->ia6_updatetime);
1398 		if (TWOHOUR < new->ndpr_vltime ||
1399 		    storedlifetime < new->ndpr_vltime) {
1400 			lt6_tmp.ia6t_vltime = new->ndpr_vltime;
1401 		} else if (storedlifetime <= TWOHOUR
1402 #if 0
1403 			   /*
1404 			    * This condition is logically redundant, so we just
1405 			    * omit it.
1406 			    * See IPng 6712, 6717, and 6721.
1407 			    */
1408 			   && new->ndpr_vltime <= storedlifetime
1409 #endif
1410 			) {
1411 			if (auth) {
1412 				lt6_tmp.ia6t_vltime = new->ndpr_vltime;
1413 			}
1414 		} else {
1415 			/*
1416 			 * new->ndpr_vltime <= TWOHOUR &&
1417 			 * TWOHOUR < storedlifetime
1418 			 */
1419 			lt6_tmp.ia6t_vltime = TWOHOUR;
1420 		}
1421 
1422 		/* The 2 hour rule is not imposed for preferred lifetime. */
1423 		lt6_tmp.ia6t_pltime = new->ndpr_pltime;
1424 
1425 		in6_init_address_ltimes(pr, &lt6_tmp);
1426 
1427 		ia6->ia6_lifetime = lt6_tmp;
1428 		ia6->ia6_updatetime = time_second;
1429 	}
1430 
1431 	if ((!autoconf || ((ifp->if_xflags & IFXF_INET6_NOPRIVACY) == 0 &&
1432 	     !tempaddr_preferred)) &&
1433 	    new->ndpr_vltime != 0 && new->ndpr_pltime != 0 &&
1434 	    !((ifp->if_xflags & IFXF_INET6_NOPRIVACY) && statique)) {
1435 		/*
1436 		 * There is no SLAAC address and/or there is no preferred RFC
1437 		 * 4941 temporary address. And prefix lifetimes are non-zero.
1438 		 * And there is no static address in the same prefix.
1439 		 * Create new addresses in process context.
1440 		 * Increment prefix refcount to ensure the prefix is not
1441 		 * removed before the task is done.
1442 		 */
1443 		pr->ndpr_refcnt++;
1444 		if (task_add(systq, &pr->ndpr_task) == 0)
1445 			pr->ndpr_refcnt--;
1446 	}
1447 
1448  end:
1449 	splx(s);
1450 	return error;
1451 }
1452 
1453 void
1454 nd6_addr_add(void *prptr)
1455 {
1456 	struct nd_prefix *pr = (struct nd_prefix *)prptr;
1457 	struct in6_ifaddr *ia6;
1458 	struct ifaddr *ifa;
1459 	int ifa_plen, autoconf, privacy, s;
1460 
1461 	s = splsoftnet();
1462 
1463 	autoconf = 1;
1464 	privacy = (pr->ndpr_ifp->if_xflags & IFXF_INET6_NOPRIVACY) == 0;
1465 
1466 	/*
1467 	 * Check again if a non-deprecated address has already
1468 	 * been autoconfigured for this prefix.
1469 	 */
1470 	TAILQ_FOREACH(ifa, &pr->ndpr_ifp->if_addrlist, ifa_list) {
1471 		if (ifa->ifa_addr->sa_family != AF_INET6)
1472 			continue;
1473 
1474 		ia6 = ifatoia6(ifa);
1475 
1476 		/*
1477 		 * Spec is not clear here, but I believe we should concentrate
1478 		 * on unicast (i.e. not anycast) addresses.
1479 		 * XXX: other ia6_flags? detached or duplicated?
1480 		 */
1481 		if ((ia6->ia6_flags & IN6_IFF_ANYCAST) != 0)
1482 			continue;
1483 
1484 		if ((ia6->ia6_flags & IN6_IFF_AUTOCONF) == 0)
1485 			continue;
1486 
1487 		if ((ia6->ia6_flags & IN6_IFF_DEPRECATED) != 0)
1488 			continue;
1489 
1490 		ifa_plen = in6_mask2len(&ia6->ia_prefixmask.sin6_addr, NULL);
1491 		if (ifa_plen == pr->ndpr_plen &&
1492 		    in6_are_prefix_equal(&ia6->ia_addr.sin6_addr,
1493 		    &pr->ndpr_prefix.sin6_addr, ifa_plen)) {
1494 			if ((ia6->ia6_flags & IN6_IFF_PRIVACY) == 0)
1495 				autoconf = 0;
1496 			else
1497 				privacy = 0;
1498 			if (!autoconf && !privacy)
1499 				break;
1500 		}
1501 	}
1502 
1503 	if (autoconf && (ia6 = in6_ifadd(pr, 0)) != NULL) {
1504 		ia6->ia6_ndpr = pr;
1505 		pr->ndpr_refcnt++;
1506 	} else
1507 		autoconf = 0;
1508 
1509 	if (privacy && (ia6 = in6_ifadd(pr, 1)) != NULL) {
1510 		ia6->ia6_ndpr = pr;
1511 		pr->ndpr_refcnt++;
1512 	} else
1513 		privacy = 0;
1514 
1515 	/*
1516 	 * A newly added address might affect the status
1517 	 * of other addresses, so we check and update it.
1518 	 * XXX: what if address duplication happens?
1519 	 */
1520 	if (autoconf || privacy)
1521 		pfxlist_onlink_check();
1522 
1523 	/* Decrement prefix refcount now that the task is done. */
1524 	if (--pr->ndpr_refcnt == 0)
1525 		prelist_remove(pr);
1526 
1527 	splx(s);
1528 }
1529 
1530 /*
1531  * A supplement function used in the on-link detection below;
1532  * detect if a given prefix has a (probably) reachable advertising router.
1533  * XXX: lengthy function name...
1534  */
1535 struct nd_pfxrouter *
1536 find_pfxlist_reachable_router(struct nd_prefix *pr)
1537 {
1538 	struct nd_pfxrouter *pfxrtr;
1539 	struct rtentry *rt = NULL;
1540 	struct llinfo_nd6 *ln;
1541 
1542 	LIST_FOREACH(pfxrtr, &pr->ndpr_advrtrs, pfr_entry) {
1543 		if ((rt = nd6_lookup(&pfxrtr->router->rtaddr, 0,
1544 		    pfxrtr->router->ifp, pfxrtr->router->ifp->if_rdomain)) &&
1545 		    (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
1546 		    ND6_IS_LLINFO_PROBREACH(ln)) {
1547 			rtfree(rt);
1548 			break;	/* found */
1549 		}
1550 		rtfree(rt);
1551 	}
1552 
1553 	return (pfxrtr);
1554 }
1555 
1556 /*
1557  * Check if each prefix in the prefix list has at least one available router
1558  * that advertised the prefix (a router is "available" if its neighbor cache
1559  * entry is reachable or probably reachable).
1560  * If the check fails, the prefix may be off-link, because, for example,
1561  * we have moved from the network but the lifetime of the prefix has not
1562  * expired yet.  So we should not use the prefix if there is another prefix
1563  * that has an available router.
1564  * But, if there is no prefix that has an available router, we still regards
1565  * all the prefixes as on-link.  This is because we can't tell if all the
1566  * routers are simply dead or if we really moved from the network and there
1567  * is no router around us.
1568  */
1569 void
1570 pfxlist_onlink_check(void)
1571 {
1572 	struct nd_prefix *pr;
1573 	struct in6_ifaddr *ia6;
1574 	char addr[INET6_ADDRSTRLEN];
1575 
1576 	/*
1577 	 * Check if there is a prefix that has a reachable advertising
1578 	 * router.
1579 	 */
1580 	LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
1581 		if (pr->ndpr_raf_onlink && find_pfxlist_reachable_router(pr))
1582 			break;
1583 	}
1584 	if (pr != NULL || !TAILQ_EMPTY(&nd_defrouter)) {
1585 		/*
1586 		 * There is at least one prefix that has a reachable router,
1587 		 * or at least a router which probably does not advertise
1588 		 * any prefixes.  The latter would be the case when we move
1589 		 * to a new link where we have a router that does not provide
1590 		 * prefixes and we configure an address by hand.
1591 		 * Detach prefixes which have no reachable advertising
1592 		 * router, and attach other prefixes.
1593 		 */
1594 		LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
1595 			/* XXX: a link-local prefix should never be detached */
1596 			if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
1597 				continue;
1598 
1599 			/*
1600 			 * we aren't interested in prefixes without the L bit
1601 			 * set.
1602 			 */
1603 			if (pr->ndpr_raf_onlink == 0)
1604 				continue;
1605 
1606 			if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
1607 			    find_pfxlist_reachable_router(pr) == NULL)
1608 				pr->ndpr_stateflags |= NDPRF_DETACHED;
1609 			if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
1610 			    find_pfxlist_reachable_router(pr) != 0)
1611 				pr->ndpr_stateflags &= ~NDPRF_DETACHED;
1612 		}
1613 	} else {
1614 		/* there is no prefix that has a reachable router */
1615 		LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
1616 			if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
1617 				continue;
1618 
1619 			if (pr->ndpr_raf_onlink == 0)
1620 				continue;
1621 
1622 			if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0)
1623 				pr->ndpr_stateflags &= ~NDPRF_DETACHED;
1624 		}
1625 	}
1626 
1627 	/*
1628 	 * Remove each interface route associated with a (just) detached
1629 	 * prefix, and reinstall the interface route for a (just) attached
1630 	 * prefix.  Note that all attempt of reinstallation does not
1631 	 * necessarily success, when a same prefix is shared among multiple
1632 	 * interfaces.  Such cases will be handled in nd6_prefix_onlink,
1633 	 * so we don't have to care about them.
1634 	 */
1635 	LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
1636 		int e;
1637 
1638 		if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
1639 			continue;
1640 
1641 		if (pr->ndpr_raf_onlink == 0)
1642 			continue;
1643 
1644 		if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
1645 		    (pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
1646 			if ((e = nd6_prefix_offlink(pr)) != 0) {
1647 				nd6log((LOG_ERR,
1648 				    "pfxlist_onlink_check: failed to "
1649 				    "make %s/%d offlink, errno=%d\n",
1650 				    inet_ntop(AF_INET6,
1651 					&pr->ndpr_prefix.sin6_addr,
1652 					addr, sizeof(addr)),
1653 				    pr->ndpr_plen, e));
1654 			}
1655 		}
1656 		if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
1657 		    (pr->ndpr_stateflags & NDPRF_ONLINK) == 0 &&
1658 		    pr->ndpr_raf_onlink) {
1659 			if ((e = nd6_prefix_onlink(pr)) != 0) {
1660 				nd6log((LOG_ERR,
1661 				    "pfxlist_onlink_check: failed to "
1662 				    "make %s/%d offlink, errno=%d\n",
1663 				    inet_ntop(AF_INET6,
1664 					&pr->ndpr_prefix.sin6_addr,
1665 					addr, sizeof(addr)),
1666 				    pr->ndpr_plen, e));
1667 			}
1668 		}
1669 	}
1670 
1671 	/*
1672 	 * Changes on the prefix status might affect address status as well.
1673 	 * Make sure that all addresses derived from an attached prefix are
1674 	 * attached, and that all addresses derived from a detached prefix are
1675 	 * detached.  Note, however, that a manually configured address should
1676 	 * always be attached.
1677 	 * The precise detection logic is same as the one for prefixes.
1678 	 */
1679 	TAILQ_FOREACH(ia6, &in6_ifaddr, ia_list) {
1680 		if (!(ia6->ia6_flags & IN6_IFF_AUTOCONF))
1681 			continue;
1682 
1683 		if (ia6->ia6_ndpr == NULL) {
1684 			/*
1685 			 * This can happen when we first configure the address
1686 			 * (i.e. the address exists, but the prefix does not).
1687 			 * XXX: complicated relationships...
1688 			 */
1689 			continue;
1690 		}
1691 
1692 		if (find_pfxlist_reachable_router(ia6->ia6_ndpr))
1693 			break;
1694 	}
1695 	if (ia6) {
1696 		TAILQ_FOREACH(ia6, &in6_ifaddr, ia_list) {
1697 			if ((ia6->ia6_flags & IN6_IFF_AUTOCONF) == 0)
1698 				continue;
1699 
1700 			if (ia6->ia6_ndpr == NULL) /* XXX: see above. */
1701 				continue;
1702 
1703 			if (find_pfxlist_reachable_router(ia6->ia6_ndpr))
1704 				ia6->ia6_flags &= ~IN6_IFF_DETACHED;
1705 			else
1706 				ia6->ia6_flags |= IN6_IFF_DETACHED;
1707 		}
1708 	}
1709 	else {
1710 		TAILQ_FOREACH(ia6, &in6_ifaddr, ia_list) {
1711 			if ((ia6->ia6_flags & IN6_IFF_AUTOCONF) == 0)
1712 				continue;
1713 
1714 			ia6->ia6_flags &= ~IN6_IFF_DETACHED;
1715 		}
1716 	}
1717 }
1718 
1719 int
1720 nd6_prefix_onlink(struct nd_prefix *pr)
1721 {
1722 	struct ifnet *ifp = pr->ndpr_ifp;
1723 	struct ifaddr *ifa;
1724 	struct nd_prefix *opr;
1725 	char addr[INET6_ADDRSTRLEN];
1726 	int error, rtflags = 0;
1727 
1728 	/* sanity check */
1729 	if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0)
1730 		return (EEXIST);
1731 
1732 	/*
1733 	 * Add the interface route associated with the prefix.  Before
1734 	 * installing the route, check if there's the same prefix on another
1735 	 * interface, and the prefix has already installed the interface route.
1736 	 * Although such a configuration is expected to be rare, we explicitly
1737 	 * allow it.
1738 	 */
1739 	LIST_FOREACH(opr, &nd_prefix, ndpr_entry) {
1740 		if (opr == pr)
1741 			continue;
1742 
1743 		if ((opr->ndpr_stateflags & NDPRF_ONLINK) == 0)
1744 			continue;
1745 
1746 		if (opr->ndpr_plen == pr->ndpr_plen &&
1747 		    in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
1748 		    &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen))
1749 			return (0);
1750 	}
1751 
1752 	TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
1753 		if (ifa->ifa_addr->sa_family != AF_INET6)
1754 			continue;
1755 		if (ifatoia6(ifa)->ia6_ndpr == pr)
1756 			break;
1757 	}
1758 	if (ifa == NULL) {
1759 		/*
1760 		 * This can still happen, when, for example, we receive an RA
1761 		 * containing a prefix with the L bit set and the A bit clear,
1762 		 * after removing all IPv6 addresses on the receiving
1763 		 * interface.  This should, of course, be rare though.
1764 		 */
1765 		nd6log((LOG_NOTICE,
1766 		    "nd6_prefix_onlink: failed to find any ifaddr"
1767 		    " to add route for a prefix(%s/%d) on %s\n",
1768 		    inet_ntop(AF_INET6,	&pr->ndpr_prefix.sin6_addr,
1769 			addr, sizeof(addr)),
1770 		    pr->ndpr_plen, ifp->if_xname));
1771 		return (0);
1772 	}
1773 
1774 	if (nd6_need_cache(ifp))
1775 		rtflags = RTF_CLONING | RTF_CONNECTED;
1776 
1777 	error = rt_ifa_add(ifa, rtflags, sin6tosa(&pr->ndpr_prefix));
1778 	if (error == 0)
1779 		pr->ndpr_stateflags |= NDPRF_ONLINK;
1780 
1781 	return (error);
1782 }
1783 
1784 int
1785 nd6_prefix_offlink(struct nd_prefix *pr)
1786 {
1787 	struct ifnet *ifp = pr->ndpr_ifp;
1788 	struct ifaddr *ifa;
1789 	struct nd_prefix *opr;
1790 	char addr[INET6_ADDRSTRLEN];
1791 	int error, rtflags = 0;
1792 
1793 	/* sanity check */
1794 	if ((pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
1795 		nd6log((LOG_ERR,
1796 		    "nd6_prefix_offlink: %s/%d is already off-link\n",
1797 		    inet_ntop(AF_INET6, &pr->ndpr_prefix.sin6_addr,
1798 			addr, sizeof(addr)),
1799 		    pr->ndpr_plen));
1800 		return (EEXIST);
1801 	}
1802 
1803 	TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
1804 		if (ifa->ifa_addr->sa_family != AF_INET6)
1805 			continue;
1806 		if (ifatoia6(ifa)->ia6_ndpr == pr)
1807 			break;
1808 	}
1809 	if (ifa == NULL)
1810 		return (EINVAL);
1811 
1812 	if (nd6_need_cache(ifp))
1813 		rtflags = RTF_CLONING | RTF_CONNECTED;
1814 
1815 	error = rt_ifa_del(ifa, rtflags, sin6tosa(&pr->ndpr_prefix));
1816 	if (error == 0) {
1817 		pr->ndpr_stateflags &= ~NDPRF_ONLINK;
1818 
1819 		/*
1820 		 * There might be the same prefix on another interface,
1821 		 * the prefix which could not be on-link just because we have
1822 		 * the interface route (see comments in nd6_prefix_onlink).
1823 		 * If there's one, try to make the prefix on-link on the
1824 		 * interface.
1825 		 */
1826 		LIST_FOREACH(opr, &nd_prefix, ndpr_entry) {
1827 			if (opr == pr)
1828 				continue;
1829 
1830 			if ((opr->ndpr_stateflags & NDPRF_ONLINK) != 0)
1831 				continue;
1832 
1833 			/*
1834 			 * KAME specific: detached prefixes should not be
1835 			 * on-link.
1836 			 */
1837 			if ((opr->ndpr_stateflags & NDPRF_DETACHED) != 0)
1838 				continue;
1839 
1840 			if (opr->ndpr_plen == pr->ndpr_plen &&
1841 			    in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
1842 			    &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
1843 				int e;
1844 
1845 				if ((e = nd6_prefix_onlink(opr)) != 0) {
1846 					nd6log((LOG_ERR,
1847 					    "nd6_prefix_offlink: failed to "
1848 					    "recover a prefix %s/%d from %s "
1849 					    "to %s (errno = %d)\n",
1850 					    inet_ntop(AF_INET6,
1851 						&pr->ndpr_prefix.sin6_addr,
1852 						addr, sizeof(addr)),
1853 					    opr->ndpr_plen, ifp->if_xname,
1854 					    opr->ndpr_ifp->if_xname, e));
1855 				}
1856 			}
1857 		}
1858 	}
1859 
1860 	return (error);
1861 }
1862 
1863 struct in6_ifaddr *
1864 in6_ifadd(struct nd_prefix *pr, int privacy)
1865 {
1866 	struct ifnet *ifp = pr->ndpr_ifp;
1867 	struct ifaddr *ifa;
1868 	struct in6_aliasreq ifra;
1869 	struct in6_ifaddr *ia6;
1870 	int error, s, plen0;
1871 	struct in6_addr mask, rand_ifid;
1872 	int prefixlen = pr->ndpr_plen;
1873 
1874 	in6_prefixlen2mask(&mask, prefixlen);
1875 
1876 	/*
1877 	 * find a link-local address (will be interface ID).
1878 	 * Is it really mandatory? Theoretically, a global or a site-local
1879 	 * address can be configured without a link-local address, if we
1880 	 * have a unique interface identifier...
1881 	 *
1882 	 * it is not mandatory to have a link-local address, we can generate
1883 	 * interface identifier on the fly.  we do this because:
1884 	 * (1) it should be the easiest way to find interface identifier.
1885 	 * (2) RFC2462 5.4 suggesting the use of the same interface identifier
1886 	 * for multiple addresses on a single interface, and possible shortcut
1887 	 * of DAD.  we omitted DAD for this reason in the past.
1888 	 * (3) a user can prevent autoconfiguration of global address
1889 	 * by removing link-local address by hand (this is partly because we
1890 	 * don't have other way to control the use of IPv6 on a interface.
1891 	 * this has been our design choice - cf. NRL's "ifconfig auto").
1892 	 * (4) it is easier to manage when an interface has addresses
1893 	 * with the same interface identifier, than to have multiple addresses
1894 	 * with different interface identifiers.
1895 	 */
1896 	ifa = &in6ifa_ifpforlinklocal(ifp, 0)->ia_ifa; /* 0 is OK? */
1897 	if (ifa)
1898 		ia6 = ifatoia6(ifa);
1899 	else
1900 		return NULL;
1901 
1902 	/* prefixlen + ifidlen must be equal to 128 */
1903 	plen0 = in6_mask2len(&ia6->ia_prefixmask.sin6_addr, NULL);
1904 	if (prefixlen != plen0) {
1905 		nd6log((LOG_INFO, "in6_ifadd: wrong prefixlen for %s "
1906 		    "(prefix=%d ifid=%d)\n",
1907 		    ifp->if_xname, prefixlen, 128 - plen0));
1908 		return NULL;
1909 	}
1910 
1911 	/* make ifaddr */
1912 	bzero(&ifra, sizeof(ifra));
1913 	strncpy(ifra.ifra_name, ifp->if_xname, sizeof(ifra.ifra_name));
1914 	ifra.ifra_addr.sin6_family = AF_INET6;
1915 	ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
1916 	/* prefix */
1917 	bcopy(&pr->ndpr_prefix.sin6_addr, &ifra.ifra_addr.sin6_addr,
1918 	    sizeof(ifra.ifra_addr.sin6_addr));
1919 	ifra.ifra_addr.sin6_addr.s6_addr32[0] &= mask.s6_addr32[0];
1920 	ifra.ifra_addr.sin6_addr.s6_addr32[1] &= mask.s6_addr32[1];
1921 	ifra.ifra_addr.sin6_addr.s6_addr32[2] &= mask.s6_addr32[2];
1922 	ifra.ifra_addr.sin6_addr.s6_addr32[3] &= mask.s6_addr32[3];
1923 
1924 	/* interface ID */
1925 	if (privacy) {
1926 		ifra.ifra_flags |= IN6_IFF_PRIVACY;
1927 		bcopy(&pr->ndpr_prefix.sin6_addr, &rand_ifid,
1928 		    sizeof(rand_ifid));
1929 		in6_get_rand_ifid(ifp, &rand_ifid);
1930 		ifra.ifra_addr.sin6_addr.s6_addr32[0] |=
1931 		    (rand_ifid.s6_addr32[0] & ~mask.s6_addr32[0]);
1932 		ifra.ifra_addr.sin6_addr.s6_addr32[1] |=
1933 		    (rand_ifid.s6_addr32[1] & ~mask.s6_addr32[1]);
1934 		ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
1935 		    (rand_ifid.s6_addr32[2] & ~mask.s6_addr32[2]);
1936 		ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
1937 		    (rand_ifid.s6_addr32[3] & ~mask.s6_addr32[3]);
1938 	} else {
1939 		ifra.ifra_addr.sin6_addr.s6_addr32[0] |=
1940 		    (ia6->ia_addr.sin6_addr.s6_addr32[0] & ~mask.s6_addr32[0]);
1941 		ifra.ifra_addr.sin6_addr.s6_addr32[1] |=
1942 		    (ia6->ia_addr.sin6_addr.s6_addr32[1] & ~mask.s6_addr32[1]);
1943 		ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
1944 		    (ia6->ia_addr.sin6_addr.s6_addr32[2] & ~mask.s6_addr32[2]);
1945 		ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
1946 		    (ia6->ia_addr.sin6_addr.s6_addr32[3] & ~mask.s6_addr32[3]);
1947 	}
1948 
1949 	/* new prefix mask. */
1950 	ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
1951 	ifra.ifra_prefixmask.sin6_family = AF_INET6;
1952 	bcopy(&mask, &ifra.ifra_prefixmask.sin6_addr,
1953 	    sizeof(ifra.ifra_prefixmask.sin6_addr));
1954 
1955 	/*
1956 	 * lifetime.
1957 	 * XXX: in6_init_address_ltimes would override these values later.
1958 	 * We should reconsider this logic.
1959 	 */
1960 	ifra.ifra_lifetime.ia6t_vltime = pr->ndpr_vltime;
1961 	ifra.ifra_lifetime.ia6t_pltime = pr->ndpr_pltime;
1962 
1963 	if (privacy) {
1964 	    if (ifra.ifra_lifetime.ia6t_vltime > ND6_PRIV_VALID_LIFETIME)
1965 		ifra.ifra_lifetime.ia6t_vltime = ND6_PRIV_VALID_LIFETIME;
1966 	    if (ifra.ifra_lifetime.ia6t_pltime > ND6_PRIV_PREFERRED_LIFETIME)
1967 		ifra.ifra_lifetime.ia6t_pltime = ND6_PRIV_PREFERRED_LIFETIME
1968 			- arc4random_uniform(ND6_PRIV_MAX_DESYNC_FACTOR);
1969 	}
1970 
1971 	/* XXX: scope zone ID? */
1972 
1973 	ifra.ifra_flags |= IN6_IFF_AUTOCONF|IN6_IFF_TENTATIVE;
1974 
1975 	/* allocate ifaddr structure, link into chain, etc. */
1976 	s = splsoftnet();
1977 	error = in6_update_ifa(ifp, &ifra, NULL);
1978 	splx(s);
1979 
1980 	if (error != 0) {
1981 		char addr[INET6_ADDRSTRLEN];
1982 
1983 		nd6log((LOG_ERR,
1984 		    "in6_ifadd: failed to make ifaddr %s on %s (errno=%d)\n",
1985 		    inet_ntop(AF_INET6,	&ifra.ifra_addr.sin6_addr,
1986 			addr, sizeof(addr)),
1987 		    ifp->if_xname, error));
1988 		return (NULL);	/* ifaddr must not have been allocated. */
1989 	}
1990 
1991 	ia6 = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
1992 
1993 	/* Perform DAD, if needed. */
1994 	if (ia6 != NULL && ia6->ia6_flags & IN6_IFF_TENTATIVE)
1995 		nd6_dad_start(&ia6->ia_ifa);
1996 
1997 	return (ia6);
1998 }
1999 
2000 int
2001 in6_init_prefix_ltimes(struct nd_prefix *ndpr)
2002 {
2003 
2004 	/* check if preferred lifetime > valid lifetime.  RFC2462 5.5.3 (c) */
2005 	if (ndpr->ndpr_pltime > ndpr->ndpr_vltime) {
2006 		nd6log((LOG_INFO, "in6_init_prefix_ltimes: preferred lifetime"
2007 		    "(%d) is greater than valid lifetime(%d)\n",
2008 		    (u_int)ndpr->ndpr_pltime, (u_int)ndpr->ndpr_vltime));
2009 		return (EINVAL);
2010 	}
2011 	if (ndpr->ndpr_pltime == ND6_INFINITE_LIFETIME)
2012 		ndpr->ndpr_preferred = 0;
2013 	else
2014 		ndpr->ndpr_preferred = time_second + ndpr->ndpr_pltime;
2015 	if (ndpr->ndpr_vltime == ND6_INFINITE_LIFETIME)
2016 		ndpr->ndpr_expire = 0;
2017 	else
2018 		ndpr->ndpr_expire = time_second + ndpr->ndpr_vltime;
2019 
2020 	return 0;
2021 }
2022 
2023 void
2024 in6_init_address_ltimes(struct nd_prefix *new, struct in6_addrlifetime *lt6)
2025 {
2026 
2027 	/* Valid lifetime must not be updated unless explicitly specified. */
2028 	/* init ia6t_expire */
2029 	if (lt6->ia6t_vltime == ND6_INFINITE_LIFETIME)
2030 		lt6->ia6t_expire = 0;
2031 	else {
2032 		lt6->ia6t_expire = time_second;
2033 		lt6->ia6t_expire += lt6->ia6t_vltime;
2034 	}
2035 
2036 	/* init ia6t_preferred */
2037 	if (lt6->ia6t_pltime == ND6_INFINITE_LIFETIME)
2038 		lt6->ia6t_preferred = 0;
2039 	else {
2040 		lt6->ia6t_preferred = time_second;
2041 		lt6->ia6t_preferred += lt6->ia6t_pltime;
2042 	}
2043 }
2044 
2045 /*
2046  * Delete all the routing table entries that use the specified gateway.
2047  * XXX: this function causes search through all entries of routing table, so
2048  * it shouldn't be called when acting as a router.
2049  */
2050 void
2051 rt6_flush(struct in6_addr *gateway, struct ifnet *ifp)
2052 {
2053 	int s;
2054 
2055 	/* We'll care only link-local addresses */
2056 	if (!IN6_IS_ADDR_LINKLOCAL(gateway))
2057 		return;
2058 
2059 	/* XXX: hack for KAME's link-local address kludge */
2060 	gateway->s6_addr16[1] = htons(ifp->if_index);
2061 
2062 	s = splsoftnet();
2063 	rtable_walk(ifp->if_rdomain, AF_INET6, rt6_deleteroute, gateway);
2064 	splx(s);
2065 }
2066 
2067 int
2068 rt6_deleteroute(struct rtentry *rt, void *arg, unsigned int id)
2069 {
2070 	struct rt_addrinfo info;
2071 	struct in6_addr *gate = (struct in6_addr *)arg;
2072 	struct sockaddr_in6 sa_mask;
2073 	int error;
2074 
2075 	if (rt->rt_gateway == NULL || rt->rt_gateway->sa_family != AF_INET6)
2076 		return (0);
2077 
2078 	if (!IN6_ARE_ADDR_EQUAL(gate, &satosin6(rt->rt_gateway)->sin6_addr))
2079 		return (0);
2080 
2081 	/*
2082 	 * Do not delete a static route.
2083 	 * XXX: this seems to be a bit ad-hoc. Should we consider the
2084 	 * 'cloned' bit instead?
2085 	 */
2086 	if ((rt->rt_flags & RTF_STATIC) != 0)
2087 		return (0);
2088 
2089 	/*
2090 	 * We delete only host route. This means, in particular, we don't
2091 	 * delete default route.
2092 	 */
2093 	if ((rt->rt_flags & RTF_HOST) == 0)
2094 		return (0);
2095 
2096 	bzero(&info, sizeof(info));
2097 	info.rti_flags =  rt->rt_flags;
2098 	info.rti_info[RTAX_DST] = rt_key(rt);
2099 	info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
2100 	info.rti_info[RTAX_NETMASK] = rt_plen2mask(rt, &sa_mask);
2101 	error = rtrequest(RTM_DELETE, &info, RTP_ANY, NULL, id);
2102 	if (error != 0)
2103 		return (error);
2104 
2105 	return (EAGAIN);
2106 }
2107