xref: /netbsd-src/sys/netinet6/nd6.c (revision 27527e67bbdf8d9ec84fd58803048ed6d181ece2)
1 /*	$NetBSD: nd6.c,v 1.96 2006/01/21 00:15:36 rpaulo Exp $	*/
2 /*	$KAME: nd6.c,v 1.279 2002/06/08 11:16:51 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/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: nd6.c,v 1.96 2006/01/21 00:15:36 rpaulo Exp $");
35 
36 #include "opt_ipsec.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/callout.h>
41 #include <sys/malloc.h>
42 #include <sys/mbuf.h>
43 #include <sys/socket.h>
44 #include <sys/sockio.h>
45 #include <sys/time.h>
46 #include <sys/kernel.h>
47 #include <sys/protosw.h>
48 #include <sys/errno.h>
49 #include <sys/ioctl.h>
50 #include <sys/syslog.h>
51 #include <sys/queue.h>
52 
53 #include <net/if.h>
54 #include <net/if_dl.h>
55 #include <net/if_types.h>
56 #include <net/route.h>
57 #include <net/if_ether.h>
58 #include <net/if_fddi.h>
59 #include <net/if_arc.h>
60 
61 #include <netinet/in.h>
62 #include <netinet6/in6_var.h>
63 #include <netinet/ip6.h>
64 #include <netinet6/ip6_var.h>
65 #include <netinet6/scope6_var.h>
66 #include <netinet6/nd6.h>
67 #include <netinet/icmp6.h>
68 
69 #ifdef IPSEC
70 #include <netinet6/ipsec.h>
71 #endif
72 
73 #include <net/net_osdep.h>
74 
75 #define ND6_SLOWTIMER_INTERVAL (60 * 60) /* 1 hour */
76 #define ND6_RECALC_REACHTM_INTERVAL (60 * 120) /* 2 hours */
77 
78 #define SIN6(s) ((struct sockaddr_in6 *)s)
79 #define SDL(s) ((struct sockaddr_dl *)s)
80 
81 /* timer values */
82 int	nd6_prune	= 1;	/* walk list every 1 seconds */
83 int	nd6_delay	= 5;	/* delay first probe time 5 second */
84 int	nd6_umaxtries	= 3;	/* maximum unicast query */
85 int	nd6_mmaxtries	= 3;	/* maximum multicast query */
86 int	nd6_useloopback = 1;	/* use loopback interface for local traffic */
87 int	nd6_gctimer	= (60 * 60 * 24); /* 1 day: garbage collection timer */
88 
89 /* preventing too many loops in ND option parsing */
90 int nd6_maxndopt = 10;	/* max # of ND options allowed */
91 
92 int nd6_maxnudhint = 0;	/* max # of subsequent upper layer hints */
93 
94 #ifdef ND6_DEBUG
95 int nd6_debug = 1;
96 #else
97 int nd6_debug = 0;
98 #endif
99 
100 /* for debugging? */
101 static int nd6_inuse, nd6_allocated;
102 
103 struct llinfo_nd6 llinfo_nd6 = {&llinfo_nd6, &llinfo_nd6};
104 struct nd_drhead nd_defrouter;
105 struct nd_prhead nd_prefix = { 0 };
106 
107 int nd6_recalc_reachtm_interval = ND6_RECALC_REACHTM_INTERVAL;
108 static struct sockaddr_in6 all1_sa;
109 
110 static void nd6_setmtu0 __P((struct ifnet *, struct nd_ifinfo *));
111 static void nd6_slowtimo __P((void *));
112 static struct llinfo_nd6 *nd6_free __P((struct rtentry *, int));
113 static void nd6_llinfo_timer __P((void *));
114 
115 struct callout nd6_slowtimo_ch = CALLOUT_INITIALIZER;
116 struct callout nd6_timer_ch = CALLOUT_INITIALIZER;
117 
118 static int fill_drlist __P((void *, size_t *, size_t));
119 static int fill_prlist __P((void *, size_t *, size_t));
120 
121 MALLOC_DEFINE(M_IP6NDP, "NDP", "IPv6 Neighbour Discovery");
122 
123 void
124 nd6_init()
125 {
126 	static int nd6_init_done = 0;
127 	int i;
128 
129 	if (nd6_init_done) {
130 		log(LOG_NOTICE, "nd6_init called more than once(ignored)\n");
131 		return;
132 	}
133 
134 	all1_sa.sin6_family = AF_INET6;
135 	all1_sa.sin6_len = sizeof(struct sockaddr_in6);
136 	for (i = 0; i < sizeof(all1_sa.sin6_addr); i++)
137 		all1_sa.sin6_addr.s6_addr[i] = 0xff;
138 
139 	/* initialization of the default router list */
140 	TAILQ_INIT(&nd_defrouter);
141 
142 	nd6_init_done = 1;
143 
144 	/* start timer */
145 	callout_reset(&nd6_slowtimo_ch, ND6_SLOWTIMER_INTERVAL * hz,
146 	    nd6_slowtimo, NULL);
147 }
148 
149 struct nd_ifinfo *
150 nd6_ifattach(ifp)
151 	struct ifnet *ifp;
152 {
153 	struct nd_ifinfo *nd;
154 
155 	nd = (struct nd_ifinfo *)malloc(sizeof(*nd), M_IP6NDP, M_WAITOK);
156 	bzero(nd, sizeof(*nd));
157 
158 	nd->initialized = 1;
159 
160 	nd->chlim = IPV6_DEFHLIM;
161 	nd->basereachable = REACHABLE_TIME;
162 	nd->reachable = ND_COMPUTE_RTIME(nd->basereachable);
163 	nd->retrans = RETRANS_TIMER;
164 	/*
165 	 * Note that the default value of ip6_accept_rtadv is 0, which means
166 	 * we won't accept RAs by default even if we set ND6_IFF_ACCEPT_RTADV
167 	 * here.
168 	 */
169 	nd->flags = (ND6_IFF_PERFORMNUD | ND6_IFF_ACCEPT_RTADV);
170 
171 	/* XXX: we cannot call nd6_setmtu since ifp is not fully initialized */
172 	nd6_setmtu0(ifp, nd);
173 
174 	return nd;
175 }
176 
177 void
178 nd6_ifdetach(nd)
179 	struct nd_ifinfo *nd;
180 {
181 
182 	free(nd, M_IP6NDP);
183 }
184 
185 void
186 nd6_setmtu(ifp)
187 	struct ifnet *ifp;
188 {
189 	nd6_setmtu0(ifp, ND_IFINFO(ifp));
190 }
191 
192 void
193 nd6_setmtu0(ifp, ndi)
194 	struct ifnet *ifp;
195 	struct nd_ifinfo *ndi;
196 {
197 	u_int32_t omaxmtu;
198 
199 	omaxmtu = ndi->maxmtu;
200 
201 	switch (ifp->if_type) {
202 	case IFT_ARCNET:
203 		ndi->maxmtu = MIN(ARC_PHDS_MAXMTU, ifp->if_mtu); /* RFC2497 */
204 		break;
205 	case IFT_FDDI:
206 		ndi->maxmtu = MIN(FDDIIPMTU, ifp->if_mtu);
207 		break;
208 	default:
209 		ndi->maxmtu = ifp->if_mtu;
210 		break;
211 	}
212 
213 	/*
214 	 * Decreasing the interface MTU under IPV6 minimum MTU may cause
215 	 * undesirable situation.  We thus notify the operator of the change
216 	 * explicitly.  The check for omaxmtu is necessary to restrict the
217 	 * log to the case of changing the MTU, not initializing it.
218 	 */
219 	if (omaxmtu >= IPV6_MMTU && ndi->maxmtu < IPV6_MMTU) {
220 		log(LOG_NOTICE, "nd6_setmtu0: new link MTU on %s (%lu) is too"
221 		    " small for IPv6 which needs %lu\n",
222 		    if_name(ifp), (unsigned long)ndi->maxmtu, (unsigned long)
223 		    IPV6_MMTU);
224 	}
225 
226 	if (ndi->maxmtu > in6_maxmtu)
227 		in6_setmaxmtu(); /* check all interfaces just in case */
228 }
229 
230 void
231 nd6_option_init(opt, icmp6len, ndopts)
232 	void *opt;
233 	int icmp6len;
234 	union nd_opts *ndopts;
235 {
236 
237 	bzero(ndopts, sizeof(*ndopts));
238 	ndopts->nd_opts_search = (struct nd_opt_hdr *)opt;
239 	ndopts->nd_opts_last
240 		= (struct nd_opt_hdr *)(((u_char *)opt) + icmp6len);
241 
242 	if (icmp6len == 0) {
243 		ndopts->nd_opts_done = 1;
244 		ndopts->nd_opts_search = NULL;
245 	}
246 }
247 
248 /*
249  * Take one ND option.
250  */
251 struct nd_opt_hdr *
252 nd6_option(ndopts)
253 	union nd_opts *ndopts;
254 {
255 	struct nd_opt_hdr *nd_opt;
256 	int olen;
257 
258 	if (!ndopts)
259 		panic("ndopts == NULL in nd6_option");
260 	if (!ndopts->nd_opts_last)
261 		panic("uninitialized ndopts in nd6_option");
262 	if (!ndopts->nd_opts_search)
263 		return NULL;
264 	if (ndopts->nd_opts_done)
265 		return NULL;
266 
267 	nd_opt = ndopts->nd_opts_search;
268 
269 	/* make sure nd_opt_len is inside the buffer */
270 	if ((caddr_t)&nd_opt->nd_opt_len >= (caddr_t)ndopts->nd_opts_last) {
271 		bzero(ndopts, sizeof(*ndopts));
272 		return NULL;
273 	}
274 
275 	olen = nd_opt->nd_opt_len << 3;
276 	if (olen == 0) {
277 		/*
278 		 * Message validation requires that all included
279 		 * options have a length that is greater than zero.
280 		 */
281 		bzero(ndopts, sizeof(*ndopts));
282 		return NULL;
283 	}
284 
285 	ndopts->nd_opts_search = (struct nd_opt_hdr *)((caddr_t)nd_opt + olen);
286 	if (ndopts->nd_opts_search > ndopts->nd_opts_last) {
287 		/* option overruns the end of buffer, invalid */
288 		bzero(ndopts, sizeof(*ndopts));
289 		return NULL;
290 	} else if (ndopts->nd_opts_search == ndopts->nd_opts_last) {
291 		/* reached the end of options chain */
292 		ndopts->nd_opts_done = 1;
293 		ndopts->nd_opts_search = NULL;
294 	}
295 	return nd_opt;
296 }
297 
298 /*
299  * Parse multiple ND options.
300  * This function is much easier to use, for ND routines that do not need
301  * multiple options of the same type.
302  */
303 int
304 nd6_options(ndopts)
305 	union nd_opts *ndopts;
306 {
307 	struct nd_opt_hdr *nd_opt;
308 	int i = 0;
309 
310 	if (!ndopts)
311 		panic("ndopts == NULL in nd6_options");
312 	if (!ndopts->nd_opts_last)
313 		panic("uninitialized ndopts in nd6_options");
314 	if (!ndopts->nd_opts_search)
315 		return 0;
316 
317 	while (1) {
318 		nd_opt = nd6_option(ndopts);
319 		if (!nd_opt && !ndopts->nd_opts_last) {
320 			/*
321 			 * Message validation requires that all included
322 			 * options have a length that is greater than zero.
323 			 */
324 			icmp6stat.icp6s_nd_badopt++;
325 			bzero(ndopts, sizeof(*ndopts));
326 			return -1;
327 		}
328 
329 		if (!nd_opt)
330 			goto skip1;
331 
332 		switch (nd_opt->nd_opt_type) {
333 		case ND_OPT_SOURCE_LINKADDR:
334 		case ND_OPT_TARGET_LINKADDR:
335 		case ND_OPT_MTU:
336 		case ND_OPT_REDIRECTED_HEADER:
337 			if (ndopts->nd_opt_array[nd_opt->nd_opt_type]) {
338 				nd6log((LOG_INFO,
339 				    "duplicated ND6 option found (type=%d)\n",
340 				    nd_opt->nd_opt_type));
341 				/* XXX bark? */
342 			} else {
343 				ndopts->nd_opt_array[nd_opt->nd_opt_type]
344 					= nd_opt;
345 			}
346 			break;
347 		case ND_OPT_PREFIX_INFORMATION:
348 			if (ndopts->nd_opt_array[nd_opt->nd_opt_type] == 0) {
349 				ndopts->nd_opt_array[nd_opt->nd_opt_type]
350 					= nd_opt;
351 			}
352 			ndopts->nd_opts_pi_end =
353 				(struct nd_opt_prefix_info *)nd_opt;
354 			break;
355 		default:
356 			/*
357 			 * Unknown options must be silently ignored,
358 			 * to accomodate future extension to the protocol.
359 			 */
360 			nd6log((LOG_DEBUG,
361 			    "nd6_options: unsupported option %d - "
362 			    "option ignored\n", nd_opt->nd_opt_type));
363 		}
364 
365 skip1:
366 		i++;
367 		if (i > nd6_maxndopt) {
368 			icmp6stat.icp6s_nd_toomanyopt++;
369 			nd6log((LOG_INFO, "too many loop in nd opt\n"));
370 			break;
371 		}
372 
373 		if (ndopts->nd_opts_done)
374 			break;
375 	}
376 
377 	return 0;
378 }
379 
380 /*
381  * ND6 timer routine to handle ND6 entries
382  */
383 void
384 nd6_llinfo_settimer(ln, xtick)
385 	struct llinfo_nd6 *ln;
386 	long xtick;
387 {
388 	int s;
389 
390 	s = splsoftnet();
391 
392 	if (xtick < 0) {
393 		ln->ln_expire = 0;
394 		ln->ln_ntick = 0;
395 		callout_stop(&ln->ln_timer_ch);
396 	} else {
397 		ln->ln_expire = time.tv_sec + xtick / hz;
398 		if (xtick > INT_MAX) {
399 			ln->ln_ntick = xtick - INT_MAX;
400 			callout_reset(&ln->ln_timer_ch, INT_MAX,
401 			    nd6_llinfo_timer, ln);
402 		} else {
403 			ln->ln_ntick = 0;
404 			callout_reset(&ln->ln_timer_ch, xtick,
405 			    nd6_llinfo_timer, ln);
406 		}
407 	}
408 
409 	splx(s);
410 }
411 
412 static void
413 nd6_llinfo_timer(arg)
414 	void *arg;
415 {
416 	int s;
417 	struct llinfo_nd6 *ln;
418 	struct rtentry *rt;
419 	const struct sockaddr_in6 *dst;
420 	struct ifnet *ifp;
421 	struct nd_ifinfo *ndi = NULL;
422 
423 	s = splsoftnet();
424 
425 	ln = (struct llinfo_nd6 *)arg;
426 
427 	if (ln->ln_ntick > 0) {
428 		if (ln->ln_ntick > INT_MAX) {
429 			ln->ln_ntick -= INT_MAX;
430 			nd6_llinfo_settimer(ln, INT_MAX);
431 		} else {
432 			ln->ln_ntick = 0;
433 			nd6_llinfo_settimer(ln, ln->ln_ntick);
434 		}
435 		splx(s);
436 		return;
437 	}
438 
439 	if ((rt = ln->ln_rt) == NULL)
440 		panic("ln->ln_rt == NULL");
441 	if ((ifp = rt->rt_ifp) == NULL)
442 		panic("ln->ln_rt->rt_ifp == NULL");
443 	ndi = ND_IFINFO(ifp);
444 	dst = (struct sockaddr_in6 *)rt_key(rt);
445 
446 	/* sanity check */
447 	if (rt->rt_llinfo && (struct llinfo_nd6 *)rt->rt_llinfo != ln)
448 		panic("rt_llinfo(%p) is not equal to ln(%p)",
449 		      rt->rt_llinfo, ln);
450 	if (!dst)
451 		panic("dst=0 in nd6_timer(ln=%p)", ln);
452 
453 	switch (ln->ln_state) {
454 	case ND6_LLINFO_INCOMPLETE:
455 		if (ln->ln_asked < nd6_mmaxtries) {
456 			ln->ln_asked++;
457 			nd6_llinfo_settimer(ln, (long)ndi->retrans * hz / 1000);
458 			nd6_ns_output(ifp, NULL, &dst->sin6_addr, ln, 0);
459 		} else {
460 			struct mbuf *m = ln->ln_hold;
461 			if (m) {
462 				/*
463 				 * assuming every packet in ln_hold has
464 				 * the same IP header
465 				 */
466 				ln->ln_hold = NULL;
467 				icmp6_error2(m, ICMP6_DST_UNREACH,
468 				    ICMP6_DST_UNREACH_ADDR, 0, rt->rt_ifp);
469 			}
470 			(void)nd6_free(rt, 0);
471 			ln = NULL;
472 		}
473 		break;
474 	case ND6_LLINFO_REACHABLE:
475 		if (!ND6_LLINFO_PERMANENT(ln)) {
476 			ln->ln_state = ND6_LLINFO_STALE;
477 			nd6_llinfo_settimer(ln, (long)nd6_gctimer * hz);
478 		}
479 		break;
480 
481 	case ND6_LLINFO_STALE:
482 		/* Garbage Collection(RFC 2461 5.3) */
483 		if (!ND6_LLINFO_PERMANENT(ln)) {
484 			(void)nd6_free(rt, 1);
485 			ln = NULL;
486 		}
487 		break;
488 
489 	case ND6_LLINFO_DELAY:
490 		if (ndi && (ndi->flags & ND6_IFF_PERFORMNUD) != 0) {
491 			/* We need NUD */
492 			ln->ln_asked = 1;
493 			ln->ln_state = ND6_LLINFO_PROBE;
494 			nd6_llinfo_settimer(ln, (long)ndi->retrans * hz / 1000);
495 			nd6_ns_output(ifp, &dst->sin6_addr,
496 			    &dst->sin6_addr, ln, 0);
497 		} else {
498 			ln->ln_state = ND6_LLINFO_STALE; /* XXX */
499 			nd6_llinfo_settimer(ln, (long)nd6_gctimer * hz);
500 		}
501 		break;
502 	case ND6_LLINFO_PROBE:
503 		if (ln->ln_asked < nd6_umaxtries) {
504 			ln->ln_asked++;
505 			nd6_llinfo_settimer(ln, (long)ndi->retrans * hz / 1000);
506 			nd6_ns_output(ifp, &dst->sin6_addr,
507 			    &dst->sin6_addr, ln, 0);
508 		} else {
509 			(void)nd6_free(rt, 0);
510 			ln = NULL;
511 		}
512 		break;
513 	}
514 
515 	splx(s);
516 }
517 
518 /*
519  * ND6 timer routine to expire default route list and prefix list
520  */
521 void
522 nd6_timer(ignored_arg)
523 	void	*ignored_arg;
524 {
525 	int s;
526 	struct nd_defrouter *dr;
527 	struct nd_prefix *pr;
528 	struct in6_ifaddr *ia6, *nia6;
529 
530 	s = splsoftnet();
531 	callout_reset(&nd6_timer_ch, nd6_prune * hz,
532 	    nd6_timer, NULL);
533 
534 	/* expire default router list */
535 	dr = TAILQ_FIRST(&nd_defrouter);
536 	while (dr) {
537 		if (dr->expire && dr->expire < time.tv_sec) {
538 			struct nd_defrouter *t;
539 			t = TAILQ_NEXT(dr, dr_entry);
540 			defrtrlist_del(dr);
541 			dr = t;
542 		} else {
543 			dr = TAILQ_NEXT(dr, dr_entry);
544 		}
545 	}
546 
547 	/*
548 	 * expire interface addresses.
549 	 * in the past the loop was inside prefix expiry processing.
550 	 * However, from a stricter speci-confrmance standpoint, we should
551 	 * rather separate address lifetimes and prefix lifetimes.
552 	 */
553 	for (ia6 = in6_ifaddr; ia6; ia6 = nia6) {
554 		nia6 = ia6->ia_next;
555 		/* check address lifetime */
556 		if (IFA6_IS_INVALID(ia6)) {
557 			in6_purgeaddr(&ia6->ia_ifa);
558 		}
559 		if (IFA6_IS_DEPRECATED(ia6)) {
560 			ia6->ia6_flags |= IN6_IFF_DEPRECATED;
561 		} else {
562 			/*
563 			 * A new RA might have made a deprecated address
564 			 * preferred.
565 			 */
566 			ia6->ia6_flags &= ~IN6_IFF_DEPRECATED;
567 		}
568 	}
569 
570 	/* expire prefix list */
571 	pr = nd_prefix.lh_first;
572 	while (pr) {
573 		/*
574 		 * check prefix lifetime.
575 		 * since pltime is just for autoconf, pltime processing for
576 		 * prefix is not necessary.
577 		 */
578 		if (pr->ndpr_vltime != ND6_INFINITE_LIFETIME &&
579 		    time.tv_sec - pr->ndpr_lastupdate > pr->ndpr_vltime) {
580 			struct nd_prefix *t;
581 			t = pr->ndpr_next;
582 
583 			/*
584 			 * address expiration and prefix expiration are
585 			 * separate.  NEVER perform in6_purgeaddr here.
586 			 */
587 
588 			prelist_remove(pr);
589 			pr = t;
590 		} else
591 			pr = pr->ndpr_next;
592 	}
593 	splx(s);
594 }
595 
596 /*
597  * Nuke neighbor cache/prefix/default router management table, right before
598  * ifp goes away.
599  */
600 void
601 nd6_purge(ifp)
602 	struct ifnet *ifp;
603 {
604 	struct llinfo_nd6 *ln, *nln;
605 	struct nd_defrouter *dr, *ndr;
606 	struct nd_prefix *pr, *npr;
607 
608 	/*
609 	 * Nuke default router list entries toward ifp.
610 	 * We defer removal of default router list entries that is installed
611 	 * in the routing table, in order to keep additional side effects as
612 	 * small as possible.
613 	 */
614 	for (dr = TAILQ_FIRST(&nd_defrouter); dr; dr = ndr) {
615 		ndr = TAILQ_NEXT(dr, dr_entry);
616 		if (dr->installed)
617 			continue;
618 
619 		if (dr->ifp == ifp)
620 			defrtrlist_del(dr);
621 	}
622 	for (dr = TAILQ_FIRST(&nd_defrouter); dr; dr = ndr) {
623 		ndr = TAILQ_NEXT(dr, dr_entry);
624 		if (!dr->installed)
625 			continue;
626 
627 		if (dr->ifp == ifp)
628 			defrtrlist_del(dr);
629 	}
630 
631 	/* Nuke prefix list entries toward ifp */
632 	for (pr = nd_prefix.lh_first; pr; pr = npr) {
633 		npr = pr->ndpr_next;
634 		if (pr->ndpr_ifp == ifp) {
635 			/*
636 			 * Because if_detach() does *not* release prefixes
637 			 * while purging addresses the reference count will
638 			 * still be above zero. We therefore reset it to
639 			 * make sure that the prefix really gets purged.
640 			 */
641 			pr->ndpr_refcnt = 0;
642 			/*
643 			 * Previously, pr->ndpr_addr is removed as well,
644 			 * but I strongly believe we don't have to do it.
645 			 * nd6_purge() is only called from in6_ifdetach(),
646 			 * which removes all the associated interface addresses
647 			 * by itself.
648 			 * (jinmei@kame.net 20010129)
649 			 */
650 			prelist_remove(pr);
651 		}
652 	}
653 
654 	/* cancel default outgoing interface setting */
655 	if (nd6_defifindex == ifp->if_index)
656 		nd6_setdefaultiface(0);
657 
658 	if (!ip6_forwarding && ip6_accept_rtadv) { /* XXX: too restrictive? */
659 		/* refresh default router list */
660 		defrouter_select();
661 	}
662 
663 	/*
664 	 * Nuke neighbor cache entries for the ifp.
665 	 * Note that rt->rt_ifp may not be the same as ifp,
666 	 * due to KAME goto ours hack.  See RTM_RESOLVE case in
667 	 * nd6_rtrequest(), and ip6_input().
668 	 */
669 	ln = llinfo_nd6.ln_next;
670 	while (ln && ln != &llinfo_nd6) {
671 		struct rtentry *rt;
672 		struct sockaddr_dl *sdl;
673 
674 		nln = ln->ln_next;
675 		rt = ln->ln_rt;
676 		if (rt && rt->rt_gateway &&
677 		    rt->rt_gateway->sa_family == AF_LINK) {
678 			sdl = (struct sockaddr_dl *)rt->rt_gateway;
679 			if (sdl->sdl_index == ifp->if_index)
680 				nln = nd6_free(rt, 0);
681 		}
682 		ln = nln;
683 	}
684 }
685 
686 struct rtentry *
687 nd6_lookup(addr6, create, ifp)
688 	struct in6_addr *addr6;
689 	int create;
690 	struct ifnet *ifp;
691 {
692 	struct rtentry *rt;
693 	struct sockaddr_in6 sin6;
694 
695 	bzero(&sin6, sizeof(sin6));
696 	sin6.sin6_len = sizeof(struct sockaddr_in6);
697 	sin6.sin6_family = AF_INET6;
698 	sin6.sin6_addr = *addr6;
699 	rt = rtalloc1((struct sockaddr *)&sin6, create);
700 	if (rt && (rt->rt_flags & RTF_LLINFO) == 0) {
701 		/*
702 		 * This is the case for the default route.
703 		 * If we want to create a neighbor cache for the address, we
704 		 * should free the route for the destination and allocate an
705 		 * interface route.
706 		 */
707 		if (create) {
708 			RTFREE(rt);
709 			rt = 0;
710 		}
711 	}
712 	if (!rt) {
713 		if (create && ifp) {
714 			int e;
715 
716 			/*
717 			 * If no route is available and create is set,
718 			 * we allocate a host route for the destination
719 			 * and treat it like an interface route.
720 			 * This hack is necessary for a neighbor which can't
721 			 * be covered by our own prefix.
722 			 */
723 			struct ifaddr *ifa =
724 			    ifaof_ifpforaddr((struct sockaddr *)&sin6, ifp);
725 			if (ifa == NULL)
726 				return (NULL);
727 
728 			/*
729 			 * Create a new route.  RTF_LLINFO is necessary
730 			 * to create a Neighbor Cache entry for the
731 			 * destination in nd6_rtrequest which will be
732 			 * called in rtrequest via ifa->ifa_rtrequest.
733 			 */
734 			if ((e = rtrequest(RTM_ADD, (struct sockaddr *)&sin6,
735 			    ifa->ifa_addr, (struct sockaddr *)&all1_sa,
736 			    (ifa->ifa_flags | RTF_HOST | RTF_LLINFO) &
737 			    ~RTF_CLONING, &rt)) != 0) {
738 #if 0
739 				log(LOG_ERR,
740 				    "nd6_lookup: failed to add route for a "
741 				    "neighbor(%s), errno=%d\n",
742 				    ip6_sprintf(addr6), e);
743 #endif
744 				return (NULL);
745 			}
746 			if (rt == NULL)
747 				return (NULL);
748 			if (rt->rt_llinfo) {
749 				struct llinfo_nd6 *ln =
750 				    (struct llinfo_nd6 *)rt->rt_llinfo;
751 				ln->ln_state = ND6_LLINFO_NOSTATE;
752 			}
753 		} else
754 			return (NULL);
755 	}
756 	rt->rt_refcnt--;
757 	/*
758 	 * Validation for the entry.
759 	 * Note that the check for rt_llinfo is necessary because a cloned
760 	 * route from a parent route that has the L flag (e.g. the default
761 	 * route to a p2p interface) may have the flag, too, while the
762 	 * destination is not actually a neighbor.
763 	 * XXX: we can't use rt->rt_ifp to check for the interface, since
764 	 *      it might be the loopback interface if the entry is for our
765 	 *      own address on a non-loopback interface. Instead, we should
766 	 *      use rt->rt_ifa->ifa_ifp, which would specify the REAL
767 	 *	interface.
768 	 */
769 	if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 ||
770 	    rt->rt_gateway->sa_family != AF_LINK || rt->rt_llinfo == NULL ||
771 	    (ifp && rt->rt_ifa->ifa_ifp != ifp)) {
772 		if (create) {
773 			nd6log((LOG_DEBUG,
774 			    "nd6_lookup: failed to lookup %s (if = %s)\n",
775 			    ip6_sprintf(addr6),
776 			    ifp ? if_name(ifp) : "unspec"));
777 		}
778 		return (NULL);
779 	}
780 	return (rt);
781 }
782 
783 /*
784  * Detect if a given IPv6 address identifies a neighbor on a given link.
785  * XXX: should take care of the destination of a p2p link?
786  */
787 int
788 nd6_is_addr_neighbor(addr, ifp)
789 	struct sockaddr_in6 *addr;
790 	struct ifnet *ifp;
791 {
792 	struct nd_prefix *pr;
793 
794 	/*
795 	 * A link-local address is always a neighbor.
796 	 * XXX: a link does not necessarily specify a single interface.
797 	 */
798 	if (IN6_IS_ADDR_LINKLOCAL(&addr->sin6_addr)) {
799 		struct sockaddr_in6 sin6_copy;
800 		u_int32_t zone;
801 
802 		/*
803 		 * We need sin6_copy since sa6_recoverscope() may modify the
804 		 * content (XXX).
805 		 */
806 		sin6_copy = *addr;
807 		if (sa6_recoverscope(&sin6_copy))
808 			return (0); /* XXX: should be impossible */
809 		if (in6_setscope(&sin6_copy.sin6_addr, ifp, &zone))
810 			return (0);
811 		if (sin6_copy.sin6_scope_id == zone)
812 			return (1);
813 		else
814 			return (0);
815 	}
816 
817 	/*
818 	 * If the address matches one of our on-link prefixes, it should be a
819 	 * neighbor.
820 	 */
821 	for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
822 		if (pr->ndpr_ifp != ifp)
823 			continue;
824 
825 		if (!(pr->ndpr_stateflags & NDPRF_ONLINK))
826 			continue;
827 
828 		if (IN6_ARE_MASKED_ADDR_EQUAL(&pr->ndpr_prefix.sin6_addr,
829 		    &addr->sin6_addr, &pr->ndpr_mask))
830 			return (1);
831 	}
832 
833 	/*
834 	 * If the default router list is empty, all addresses are regarded
835 	 * as on-link, and thus, as a neighbor.
836 	 * XXX: we restrict the condition to hosts, because routers usually do
837 	 * not have the "default router list".
838 	 */
839 	if (!ip6_forwarding && TAILQ_FIRST(&nd_defrouter) == NULL &&
840 	    nd6_defifindex == ifp->if_index) {
841 		return (1);
842 	}
843 
844 	/*
845 	 * Even if the address matches none of our addresses, it might be
846 	 * in the neighbor cache.
847 	 */
848 	if (nd6_lookup(&addr->sin6_addr, 0, ifp) != NULL)
849 		return (1);
850 
851 	return (0);
852 }
853 
854 /*
855  * Free an nd6 llinfo entry.
856  * Since the function would cause significant changes in the kernel, DO NOT
857  * make it global, unless you have a strong reason for the change, and are sure
858  * that the change is safe.
859  */
860 static struct llinfo_nd6 *
861 nd6_free(rt, gc)
862 	struct rtentry *rt;
863 	int gc;
864 {
865 	struct llinfo_nd6 *ln = (struct llinfo_nd6 *)rt->rt_llinfo, *next;
866 	struct in6_addr in6 = ((struct sockaddr_in6 *)rt_key(rt))->sin6_addr;
867 	struct nd_defrouter *dr;
868 
869 	/*
870 	 * we used to have pfctlinput(PRC_HOSTDEAD) here.
871 	 * even though it is not harmful, it was not really necessary.
872 	 */
873 
874 	/* cancel timer */
875 	nd6_llinfo_settimer(ln, -1);
876 
877 	if (!ip6_forwarding) {
878 		int s;
879 		s = splsoftnet();
880 		dr = defrouter_lookup(&((struct sockaddr_in6 *)rt_key(rt))->sin6_addr,
881 		    rt->rt_ifp);
882 
883 		if (dr != NULL && dr->expire &&
884 		    ln->ln_state == ND6_LLINFO_STALE && gc) {
885 			/*
886 			 * If the reason for the deletion is just garbage
887 			 * collection, and the neighbor is an active default
888 			 * router, do not delete it.  Instead, reset the GC
889 			 * timer using the router's lifetime.
890 			 * Simply deleting the entry would affect default
891 			 * router selection, which is not necessarily a good
892 			 * thing, especially when we're using router preference
893 			 * values.
894 			 * XXX: the check for ln_state would be redundant,
895 			 *      but we intentionally keep it just in case.
896 			 */
897 			if (dr->expire > time.tv_sec)
898 				nd6_llinfo_settimer(ln,
899 				    (dr->expire - time.tv_sec) * hz);
900 			else
901 				nd6_llinfo_settimer(ln, (long)nd6_gctimer * hz);
902 			splx(s);
903 			return (ln->ln_next);
904 		}
905 
906 		if (ln->ln_router || dr) {
907 			/*
908 			 * rt6_flush must be called whether or not the neighbor
909 			 * is in the Default Router List.
910 			 * See a corresponding comment in nd6_na_input().
911 			 */
912 			rt6_flush(&in6, rt->rt_ifp);
913 		}
914 
915 		if (dr) {
916 			/*
917 			 * Unreachablity of a router might affect the default
918 			 * router selection and on-link detection of advertised
919 			 * prefixes.
920 			 */
921 
922 			/*
923 			 * Temporarily fake the state to choose a new default
924 			 * router and to perform on-link determination of
925 			 * prefixes correctly.
926 			 * Below the state will be set correctly,
927 			 * or the entry itself will be deleted.
928 			 */
929 			ln->ln_state = ND6_LLINFO_INCOMPLETE;
930 
931 			/*
932 			 * Since defrouter_select() does not affect the
933 			 * on-link determination and MIP6 needs the check
934 			 * before the default router selection, we perform
935 			 * the check now.
936 			 */
937 			pfxlist_onlink_check();
938 
939 			/*
940 			 * refresh default router list
941 			 */
942 			defrouter_select();
943 		}
944 		splx(s);
945 	}
946 
947 	/*
948 	 * Before deleting the entry, remember the next entry as the
949 	 * return value.  We need this because pfxlist_onlink_check() above
950 	 * might have freed other entries (particularly the old next entry) as
951 	 * a side effect (XXX).
952 	 */
953 	next = ln->ln_next;
954 
955 	/*
956 	 * Detach the route from the routing tree and the list of neighbor
957 	 * caches, and disable the route entry not to be used in already
958 	 * cached routes.
959 	 */
960 	rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0,
961 	    rt_mask(rt), 0, (struct rtentry **)0);
962 
963 	return (next);
964 }
965 
966 /*
967  * Upper-layer reachability hint for Neighbor Unreachability Detection.
968  *
969  * XXX cost-effective metods?
970  */
971 void
972 nd6_nud_hint(rt, dst6, force)
973 	struct rtentry *rt;
974 	struct in6_addr *dst6;
975 	int force;
976 {
977 	struct llinfo_nd6 *ln;
978 
979 	/*
980 	 * If the caller specified "rt", use that.  Otherwise, resolve the
981 	 * routing table by supplied "dst6".
982 	 */
983 	if (!rt) {
984 		if (!dst6)
985 			return;
986 		if (!(rt = nd6_lookup(dst6, 0, NULL)))
987 			return;
988 	}
989 
990 	if ((rt->rt_flags & RTF_GATEWAY) != 0 ||
991 	    (rt->rt_flags & RTF_LLINFO) == 0 ||
992 	    !rt->rt_llinfo || !rt->rt_gateway ||
993 	    rt->rt_gateway->sa_family != AF_LINK) {
994 		/* This is not a host route. */
995 		return;
996 	}
997 
998 	ln = (struct llinfo_nd6 *)rt->rt_llinfo;
999 	if (ln->ln_state < ND6_LLINFO_REACHABLE)
1000 		return;
1001 
1002 	/*
1003 	 * if we get upper-layer reachability confirmation many times,
1004 	 * it is possible we have false information.
1005 	 */
1006 	if (!force) {
1007 		ln->ln_byhint++;
1008 		if (ln->ln_byhint > nd6_maxnudhint)
1009 			return;
1010 	}
1011 
1012 	ln->ln_state = ND6_LLINFO_REACHABLE;
1013 	if (!ND6_LLINFO_PERMANENT(ln)) {
1014 		nd6_llinfo_settimer(ln,
1015 		    (long)ND_IFINFO(rt->rt_ifp)->reachable * hz);
1016 	}
1017 }
1018 
1019 void
1020 nd6_rtrequest(req, rt, info)
1021 	int	req;
1022 	struct rtentry *rt;
1023 	struct rt_addrinfo *info; /* xxx unused */
1024 {
1025 	struct sockaddr *gate = rt->rt_gateway;
1026 	struct llinfo_nd6 *ln = (struct llinfo_nd6 *)rt->rt_llinfo;
1027 	static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
1028 	struct ifnet *ifp = rt->rt_ifp;
1029 	struct ifaddr *ifa;
1030 
1031 	if ((rt->rt_flags & RTF_GATEWAY) != 0)
1032 		return;
1033 
1034 	if (nd6_need_cache(ifp) == 0 && (rt->rt_flags & RTF_HOST) == 0) {
1035 		/*
1036 		 * This is probably an interface direct route for a link
1037 		 * which does not need neighbor caches (e.g. fe80::%lo0/64).
1038 		 * We do not need special treatment below for such a route.
1039 		 * Moreover, the RTF_LLINFO flag which would be set below
1040 		 * would annoy the ndp(8) command.
1041 		 */
1042 		return;
1043 	}
1044 
1045 	if (req == RTM_RESOLVE &&
1046 	    (nd6_need_cache(ifp) == 0 || /* stf case */
1047 	     !nd6_is_addr_neighbor((struct sockaddr_in6 *)rt_key(rt), ifp))) {
1048 		/*
1049 		 * FreeBSD and BSD/OS often make a cloned host route based
1050 		 * on a less-specific route (e.g. the default route).
1051 		 * If the less specific route does not have a "gateway"
1052 		 * (this is the case when the route just goes to a p2p or an
1053 		 * stf interface), we'll mistakenly make a neighbor cache for
1054 		 * the host route, and will see strange neighbor solicitation
1055 		 * for the corresponding destination.  In order to avoid the
1056 		 * confusion, we check if the destination of the route is
1057 		 * a neighbor in terms of neighbor discovery, and stop the
1058 		 * process if not.  Additionally, we remove the LLINFO flag
1059 		 * so that ndp(8) will not try to get the neighbor information
1060 		 * of the destination.
1061 		 */
1062 		rt->rt_flags &= ~RTF_LLINFO;
1063 		return;
1064 	}
1065 
1066 	switch (req) {
1067 	case RTM_ADD:
1068 		/*
1069 		 * There is no backward compatibility :)
1070 		 *
1071 		 * if ((rt->rt_flags & RTF_HOST) == 0 &&
1072 		 *     SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
1073 		 *	   rt->rt_flags |= RTF_CLONING;
1074 		 */
1075 		if ((rt->rt_flags & RTF_CLONING) ||
1076 		    ((rt->rt_flags & RTF_LLINFO) && !ln)) {
1077 			/*
1078 			 * Case 1: This route should come from a route to
1079 			 * interface (RTF_CLONING case) or the route should be
1080 			 * treated as on-link but is currently not
1081 			 * (RTF_LLINFO && !ln case).
1082 			 */
1083 			rt_setgate(rt, rt_key(rt),
1084 				   (struct sockaddr *)&null_sdl);
1085 			gate = rt->rt_gateway;
1086 			SDL(gate)->sdl_type = ifp->if_type;
1087 			SDL(gate)->sdl_index = ifp->if_index;
1088 			if (ln)
1089 				nd6_llinfo_settimer(ln, 0);
1090 			if ((rt->rt_flags & RTF_CLONING) != 0)
1091 				break;
1092 		}
1093 		/*
1094 		 * In IPv4 code, we try to annonuce new RTF_ANNOUNCE entry here.
1095 		 * We don't do that here since llinfo is not ready yet.
1096 		 *
1097 		 * There are also couple of other things to be discussed:
1098 		 * - unsolicited NA code needs improvement beforehand
1099 		 * - RFC2461 says we MAY send multicast unsolicited NA
1100 		 *   (7.2.6 paragraph 4), however, it also says that we
1101 		 *   SHOULD provide a mechanism to prevent multicast NA storm.
1102 		 *   we don't have anything like it right now.
1103 		 *   note that the mechanism needs a mutual agreement
1104 		 *   between proxies, which means that we need to implement
1105 		 *   a new protocol, or a new kludge.
1106 		 * - from RFC2461 6.2.4, host MUST NOT send an unsolicited NA.
1107 		 *   we need to check ip6forwarding before sending it.
1108 		 *   (or should we allow proxy ND configuration only for
1109 		 *   routers?  there's no mention about proxy ND from hosts)
1110 		 */
1111 #if 0
1112 		/* XXX it does not work */
1113 		if (rt->rt_flags & RTF_ANNOUNCE)
1114 			nd6_na_output(ifp,
1115 			      &SIN6(rt_key(rt))->sin6_addr,
1116 			      &SIN6(rt_key(rt))->sin6_addr,
1117 			      ip6_forwarding ? ND_NA_FLAG_ROUTER : 0,
1118 			      1, NULL);
1119 #endif
1120 		/* FALLTHROUGH */
1121 	case RTM_RESOLVE:
1122 		if ((ifp->if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK)) == 0) {
1123 			/*
1124 			 * Address resolution isn't necessary for a point to
1125 			 * point link, so we can skip this test for a p2p link.
1126 			 */
1127 			if (gate->sa_family != AF_LINK ||
1128 			    gate->sa_len < sizeof(null_sdl)) {
1129 				log(LOG_DEBUG,
1130 				    "nd6_rtrequest: bad gateway value: %s\n",
1131 				    if_name(ifp));
1132 				break;
1133 			}
1134 			SDL(gate)->sdl_type = ifp->if_type;
1135 			SDL(gate)->sdl_index = ifp->if_index;
1136 		}
1137 		if (ln != NULL)
1138 			break;	/* This happens on a route change */
1139 		/*
1140 		 * Case 2: This route may come from cloning, or a manual route
1141 		 * add with a LL address.
1142 		 */
1143 		R_Malloc(ln, struct llinfo_nd6 *, sizeof(*ln));
1144 		rt->rt_llinfo = (caddr_t)ln;
1145 		if (!ln) {
1146 			log(LOG_DEBUG, "nd6_rtrequest: malloc failed\n");
1147 			break;
1148 		}
1149 		nd6_inuse++;
1150 		nd6_allocated++;
1151 		Bzero(ln, sizeof(*ln));
1152 		ln->ln_rt = rt;
1153 		callout_init(&ln->ln_timer_ch);
1154 		/* this is required for "ndp" command. - shin */
1155 		if (req == RTM_ADD) {
1156 		        /*
1157 			 * gate should have some valid AF_LINK entry,
1158 			 * and ln->ln_expire should have some lifetime
1159 			 * which is specified by ndp command.
1160 			 */
1161 			ln->ln_state = ND6_LLINFO_REACHABLE;
1162 			ln->ln_byhint = 0;
1163 		} else {
1164 		        /*
1165 			 * When req == RTM_RESOLVE, rt is created and
1166 			 * initialized in rtrequest(), so rt_expire is 0.
1167 			 */
1168 			ln->ln_state = ND6_LLINFO_NOSTATE;
1169 			nd6_llinfo_settimer(ln, 0);
1170 		}
1171 		rt->rt_flags |= RTF_LLINFO;
1172 		ln->ln_next = llinfo_nd6.ln_next;
1173 		llinfo_nd6.ln_next = ln;
1174 		ln->ln_prev = &llinfo_nd6;
1175 		ln->ln_next->ln_prev = ln;
1176 
1177 		/*
1178 		 * check if rt_key(rt) is one of my address assigned
1179 		 * to the interface.
1180 		 */
1181 		ifa = (struct ifaddr *)in6ifa_ifpwithaddr(rt->rt_ifp,
1182 		    &SIN6(rt_key(rt))->sin6_addr);
1183 		if (ifa) {
1184 			caddr_t macp = nd6_ifptomac(ifp);
1185 			nd6_llinfo_settimer(ln, -1);
1186 			ln->ln_state = ND6_LLINFO_REACHABLE;
1187 			ln->ln_byhint = 0;
1188 			if (macp) {
1189 				Bcopy(macp, LLADDR(SDL(gate)), ifp->if_addrlen);
1190 				SDL(gate)->sdl_alen = ifp->if_addrlen;
1191 			}
1192 			if (nd6_useloopback) {
1193 				rt->rt_ifp = lo0ifp;	/* XXX */
1194 				/*
1195 				 * Make sure rt_ifa be equal to the ifaddr
1196 				 * corresponding to the address.
1197 				 * We need this because when we refer
1198 				 * rt_ifa->ia6_flags in ip6_input, we assume
1199 				 * that the rt_ifa points to the address instead
1200 				 * of the loopback address.
1201 				 */
1202 				if (ifa != rt->rt_ifa) {
1203 					IFAFREE(rt->rt_ifa);
1204 					IFAREF(ifa);
1205 					rt->rt_ifa = ifa;
1206 				}
1207 			}
1208 		} else if (rt->rt_flags & RTF_ANNOUNCE) {
1209 			nd6_llinfo_settimer(ln, -1);
1210 			ln->ln_state = ND6_LLINFO_REACHABLE;
1211 			ln->ln_byhint = 0;
1212 
1213 			/* join solicited node multicast for proxy ND */
1214 			if (ifp->if_flags & IFF_MULTICAST) {
1215 				struct in6_addr llsol;
1216 				int error;
1217 
1218 				llsol = SIN6(rt_key(rt))->sin6_addr;
1219 				llsol.s6_addr32[0] = htonl(0xff020000);
1220 				llsol.s6_addr32[1] = 0;
1221 				llsol.s6_addr32[2] = htonl(1);
1222 				llsol.s6_addr8[12] = 0xff;
1223 				if (in6_setscope(&llsol, ifp, NULL))
1224 					break;
1225 				if (!in6_addmulti(&llsol, ifp, &error)) {
1226 					nd6log((LOG_ERR, "%s: failed to join "
1227 					    "%s (errno=%d)\n", if_name(ifp),
1228 					    ip6_sprintf(&llsol), error));
1229 				}
1230 			}
1231 		}
1232 		break;
1233 
1234 	case RTM_DELETE:
1235 		if (!ln)
1236 			break;
1237 		/* leave from solicited node multicast for proxy ND */
1238 		if ((rt->rt_flags & RTF_ANNOUNCE) != 0 &&
1239 		    (ifp->if_flags & IFF_MULTICAST) != 0) {
1240 			struct in6_addr llsol;
1241 			struct in6_multi *in6m;
1242 
1243 			llsol = SIN6(rt_key(rt))->sin6_addr;
1244 			llsol.s6_addr32[0] = htonl(0xff020000);
1245 			llsol.s6_addr32[1] = 0;
1246 			llsol.s6_addr32[2] = htonl(1);
1247 			llsol.s6_addr8[12] = 0xff;
1248 			if (in6_setscope(&llsol, ifp, NULL) == 0) {
1249 				IN6_LOOKUP_MULTI(llsol, ifp, in6m);
1250 				if (in6m)
1251 					in6_delmulti(in6m);
1252 			} else
1253 				; /* XXX: should not happen. bark here? */
1254 		}
1255 		nd6_inuse--;
1256 		ln->ln_next->ln_prev = ln->ln_prev;
1257 		ln->ln_prev->ln_next = ln->ln_next;
1258 		ln->ln_prev = NULL;
1259 		nd6_llinfo_settimer(ln, -1);
1260 		rt->rt_llinfo = 0;
1261 		rt->rt_flags &= ~RTF_LLINFO;
1262 		if (ln->ln_hold)
1263 			m_freem(ln->ln_hold);
1264 		Free((caddr_t)ln);
1265 	}
1266 }
1267 
1268 int
1269 nd6_ioctl(cmd, data, ifp)
1270 	u_long cmd;
1271 	caddr_t	data;
1272 	struct ifnet *ifp;
1273 {
1274 	struct in6_drlist *drl = (struct in6_drlist *)data;
1275 	struct in6_oprlist *oprl = (struct in6_oprlist *)data;
1276 	struct in6_ndireq *ndi = (struct in6_ndireq *)data;
1277 	struct in6_nbrinfo *nbi = (struct in6_nbrinfo *)data;
1278 	struct in6_ndifreq *ndif = (struct in6_ndifreq *)data;
1279 	struct nd_defrouter *dr;
1280 	struct nd_prefix *pr;
1281 	struct rtentry *rt;
1282 	int i = 0, error = 0;
1283 	int s;
1284 
1285 	switch (cmd) {
1286 	case SIOCGDRLST_IN6:
1287 		/*
1288 		 * obsolete API, use sysctl under net.inet6.icmp6
1289 		 */
1290 		bzero(drl, sizeof(*drl));
1291 		s = splsoftnet();
1292 		dr = TAILQ_FIRST(&nd_defrouter);
1293 		while (dr && i < DRLSTSIZ) {
1294 			drl->defrouter[i].rtaddr = dr->rtaddr;
1295 			in6_clearscope(&drl->defrouter[i].rtaddr);
1296 
1297 			drl->defrouter[i].flags = dr->flags;
1298 			drl->defrouter[i].rtlifetime = dr->rtlifetime;
1299 			drl->defrouter[i].expire = dr->expire;
1300 			drl->defrouter[i].if_index = dr->ifp->if_index;
1301 			i++;
1302 			dr = TAILQ_NEXT(dr, dr_entry);
1303 		}
1304 		splx(s);
1305 		break;
1306 	case SIOCGPRLST_IN6:
1307 		/*
1308 		 * obsolete API, use sysctl under net.inet6.icmp6
1309 		 *
1310 		 * XXX the structure in6_prlist was changed in backward-
1311 		 * incompatible manner.  in6_oprlist is used for SIOCGPRLST_IN6,
1312 		 * in6_prlist is used for nd6_sysctl() - fill_prlist().
1313 		 */
1314 		/*
1315 		 * XXX meaning of fields, especialy "raflags", is very
1316 		 * differnet between RA prefix list and RR/static prefix list.
1317 		 * how about separating ioctls into two?
1318 		 */
1319 		bzero(oprl, sizeof(*oprl));
1320 		s = splsoftnet();
1321 		pr = nd_prefix.lh_first;
1322 		while (pr && i < PRLSTSIZ) {
1323 			struct nd_pfxrouter *pfr;
1324 			int j;
1325 
1326 			oprl->prefix[i].prefix = pr->ndpr_prefix.sin6_addr;
1327 			oprl->prefix[i].raflags = pr->ndpr_raf;
1328 			oprl->prefix[i].prefixlen = pr->ndpr_plen;
1329 			oprl->prefix[i].vltime = pr->ndpr_vltime;
1330 			oprl->prefix[i].pltime = pr->ndpr_pltime;
1331 			oprl->prefix[i].if_index = pr->ndpr_ifp->if_index;
1332 			oprl->prefix[i].expire = pr->ndpr_expire;
1333 
1334 			pfr = pr->ndpr_advrtrs.lh_first;
1335 			j = 0;
1336 			while (pfr) {
1337 				if (j < DRLSTSIZ) {
1338 #define RTRADDR oprl->prefix[i].advrtr[j]
1339 					RTRADDR = pfr->router->rtaddr;
1340 					in6_clearscope(&RTRADDR);
1341 #undef RTRADDR
1342 				}
1343 				j++;
1344 				pfr = pfr->pfr_next;
1345 			}
1346 			oprl->prefix[i].advrtrs = j;
1347 			oprl->prefix[i].origin = PR_ORIG_RA;
1348 
1349 			i++;
1350 			pr = pr->ndpr_next;
1351 		}
1352 		splx(s);
1353 
1354 		break;
1355 	case OSIOCGIFINFO_IN6:
1356 		/* XXX: old ndp(8) assumes a positive value for linkmtu. */
1357 		bzero(&ndi->ndi, sizeof(ndi->ndi));
1358 		ndi->ndi.linkmtu = IN6_LINKMTU(ifp);
1359 		ndi->ndi.maxmtu = ND_IFINFO(ifp)->maxmtu;
1360 		ndi->ndi.basereachable = ND_IFINFO(ifp)->basereachable;
1361 		ndi->ndi.reachable = ND_IFINFO(ifp)->reachable;
1362 		ndi->ndi.retrans = ND_IFINFO(ifp)->retrans;
1363 		ndi->ndi.flags = ND_IFINFO(ifp)->flags;
1364 		ndi->ndi.recalctm = ND_IFINFO(ifp)->recalctm;
1365 		ndi->ndi.chlim = ND_IFINFO(ifp)->chlim;
1366 		break;
1367 	case SIOCGIFINFO_IN6:
1368 		ndi->ndi = *ND_IFINFO(ifp);
1369 		break;
1370 	case SIOCSIFINFO_FLAGS:
1371 		ND_IFINFO(ifp)->flags = ndi->ndi.flags;
1372 		break;
1373 	case SIOCSNDFLUSH_IN6:	/* XXX: the ioctl name is confusing... */
1374 		/* sync kernel routing table with the default router list */
1375 		defrouter_reset();
1376 		defrouter_select();
1377 		break;
1378 	case SIOCSPFXFLUSH_IN6:
1379 	{
1380 		/* flush all the prefix advertised by routers */
1381 		struct nd_prefix *pfx, *next;
1382 
1383 		s = splsoftnet();
1384 		for (pfx = nd_prefix.lh_first; pfx; pfx = next) {
1385 			struct in6_ifaddr *ia, *ia_next;
1386 
1387 			next = pfx->ndpr_next;
1388 
1389 			if (IN6_IS_ADDR_LINKLOCAL(&pfx->ndpr_prefix.sin6_addr))
1390 				continue; /* XXX */
1391 
1392 			/* do we really have to remove addresses as well? */
1393 			for (ia = in6_ifaddr; ia; ia = ia_next) {
1394 				/* ia might be removed.  keep the next ptr. */
1395 				ia_next = ia->ia_next;
1396 
1397 				if ((ia->ia6_flags & IN6_IFF_AUTOCONF) == 0)
1398 					continue;
1399 
1400 				if (ia->ia6_ndpr == pfx)
1401 					in6_purgeaddr(&ia->ia_ifa);
1402 			}
1403 			prelist_remove(pfx);
1404 		}
1405 		splx(s);
1406 		break;
1407 	}
1408 	case SIOCSRTRFLUSH_IN6:
1409 	{
1410 		/* flush all the default routers */
1411 		struct nd_defrouter *drtr, *next;
1412 
1413 		s = splsoftnet();
1414 		defrouter_reset();
1415 		for (drtr = TAILQ_FIRST(&nd_defrouter); drtr; drtr = next) {
1416 			next = TAILQ_NEXT(drtr, dr_entry);
1417 			defrtrlist_del(drtr);
1418 		}
1419 		defrouter_select();
1420 		splx(s);
1421 		break;
1422 	}
1423 	case SIOCGNBRINFO_IN6:
1424 	    {
1425 		struct llinfo_nd6 *ln;
1426 		struct in6_addr nb_addr = nbi->addr; /* make local for safety */
1427 
1428 		if ((error = in6_setscope(&nb_addr, ifp, NULL)) != 0)
1429 			return (error);
1430 
1431 		s = splsoftnet();
1432 		if ((rt = nd6_lookup(&nb_addr, 0, ifp)) == NULL ||
1433 		    (ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) {
1434 			error = EINVAL;
1435 			splx(s);
1436 			break;
1437 		}
1438 		nbi->state = ln->ln_state;
1439 		nbi->asked = ln->ln_asked;
1440 		nbi->isrouter = ln->ln_router;
1441 		nbi->expire = ln->ln_expire;
1442 		splx(s);
1443 
1444 		break;
1445 	}
1446 	case SIOCGDEFIFACE_IN6:	/* XXX: should be implemented as a sysctl? */
1447 		ndif->ifindex = nd6_defifindex;
1448 		break;
1449 	case SIOCSDEFIFACE_IN6:	/* XXX: should be implemented as a sysctl? */
1450 		return (nd6_setdefaultiface(ndif->ifindex));
1451 	}
1452 	return (error);
1453 }
1454 
1455 /*
1456  * Create neighbor cache entry and cache link-layer address,
1457  * on reception of inbound ND6 packets.  (RS/RA/NS/redirect)
1458  */
1459 struct rtentry *
1460 nd6_cache_lladdr(ifp, from, lladdr, lladdrlen, type, code)
1461 	struct ifnet *ifp;
1462 	struct in6_addr *from;
1463 	char *lladdr;
1464 	int lladdrlen;
1465 	int type;	/* ICMP6 type */
1466 	int code;	/* type dependent information */
1467 {
1468 	struct rtentry *rt = NULL;
1469 	struct llinfo_nd6 *ln = NULL;
1470 	int is_newentry;
1471 	struct sockaddr_dl *sdl = NULL;
1472 	int do_update;
1473 	int olladdr;
1474 	int llchange;
1475 	int newstate = 0;
1476 
1477 	if (!ifp)
1478 		panic("ifp == NULL in nd6_cache_lladdr");
1479 	if (!from)
1480 		panic("from == NULL in nd6_cache_lladdr");
1481 
1482 	/* nothing must be updated for unspecified address */
1483 	if (IN6_IS_ADDR_UNSPECIFIED(from))
1484 		return NULL;
1485 
1486 	/*
1487 	 * Validation about ifp->if_addrlen and lladdrlen must be done in
1488 	 * the caller.
1489 	 *
1490 	 * XXX If the link does not have link-layer adderss, what should
1491 	 * we do? (ifp->if_addrlen == 0)
1492 	 * Spec says nothing in sections for RA, RS and NA.  There's small
1493 	 * description on it in NS section (RFC 2461 7.2.3).
1494 	 */
1495 
1496 	rt = nd6_lookup(from, 0, ifp);
1497 	if (!rt) {
1498 #if 0
1499 		/* nothing must be done if there's no lladdr */
1500 		if (!lladdr || !lladdrlen)
1501 			return NULL;
1502 #endif
1503 
1504 		rt = nd6_lookup(from, 1, ifp);
1505 		is_newentry = 1;
1506 	} else {
1507 		/* do nothing if static ndp is set */
1508 		if (rt->rt_flags & RTF_STATIC)
1509 			return NULL;
1510 		is_newentry = 0;
1511 	}
1512 
1513 	if (!rt)
1514 		return NULL;
1515 	if ((rt->rt_flags & (RTF_GATEWAY | RTF_LLINFO)) != RTF_LLINFO) {
1516 fail:
1517 		(void)nd6_free(rt, 0);
1518 		return NULL;
1519 	}
1520 	ln = (struct llinfo_nd6 *)rt->rt_llinfo;
1521 	if (!ln)
1522 		goto fail;
1523 	if (!rt->rt_gateway)
1524 		goto fail;
1525 	if (rt->rt_gateway->sa_family != AF_LINK)
1526 		goto fail;
1527 	sdl = SDL(rt->rt_gateway);
1528 
1529 	olladdr = (sdl->sdl_alen) ? 1 : 0;
1530 	if (olladdr && lladdr) {
1531 		if (bcmp(lladdr, LLADDR(sdl), ifp->if_addrlen))
1532 			llchange = 1;
1533 		else
1534 			llchange = 0;
1535 	} else
1536 		llchange = 0;
1537 
1538 	/*
1539 	 * newentry olladdr  lladdr  llchange	(*=record)
1540 	 *	0	n	n	--	(1)
1541 	 *	0	y	n	--	(2)
1542 	 *	0	n	y	--	(3) * STALE
1543 	 *	0	y	y	n	(4) *
1544 	 *	0	y	y	y	(5) * STALE
1545 	 *	1	--	n	--	(6)   NOSTATE(= PASSIVE)
1546 	 *	1	--	y	--	(7) * STALE
1547 	 */
1548 
1549 	if (lladdr) {		/* (3-5) and (7) */
1550 		/*
1551 		 * Record source link-layer address
1552 		 * XXX is it dependent to ifp->if_type?
1553 		 */
1554 		sdl->sdl_alen = ifp->if_addrlen;
1555 		bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
1556 	}
1557 
1558 	if (!is_newentry) {
1559 		if ((!olladdr && lladdr) ||		/* (3) */
1560 		    (olladdr && lladdr && llchange)) {	/* (5) */
1561 			do_update = 1;
1562 			newstate = ND6_LLINFO_STALE;
1563 		} else					/* (1-2,4) */
1564 			do_update = 0;
1565 	} else {
1566 		do_update = 1;
1567 		if (!lladdr)				/* (6) */
1568 			newstate = ND6_LLINFO_NOSTATE;
1569 		else					/* (7) */
1570 			newstate = ND6_LLINFO_STALE;
1571 	}
1572 
1573 	if (do_update) {
1574 		/*
1575 		 * Update the state of the neighbor cache.
1576 		 */
1577 		ln->ln_state = newstate;
1578 
1579 		if (ln->ln_state == ND6_LLINFO_STALE) {
1580 			/*
1581 			 * XXX: since nd6_output() below will cause
1582 			 * state tansition to DELAY and reset the timer,
1583 			 * we must set the timer now, although it is actually
1584 			 * meaningless.
1585 			 */
1586 			nd6_llinfo_settimer(ln, (long)nd6_gctimer * hz);
1587 
1588 			if (ln->ln_hold) {
1589 				/*
1590 				 * we assume ifp is not a p2p here, so just
1591 				 * set the 2nd argument as the 1st one.
1592 				 */
1593 				nd6_output(ifp, ifp, ln->ln_hold,
1594 				    (struct sockaddr_in6 *)rt_key(rt), rt);
1595 				ln->ln_hold = NULL;
1596 			}
1597 		} else if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
1598 			/* probe right away */
1599 			nd6_llinfo_settimer((void *)ln, 0);
1600 		}
1601 	}
1602 
1603 	/*
1604 	 * ICMP6 type dependent behavior.
1605 	 *
1606 	 * NS: clear IsRouter if new entry
1607 	 * RS: clear IsRouter
1608 	 * RA: set IsRouter if there's lladdr
1609 	 * redir: clear IsRouter if new entry
1610 	 *
1611 	 * RA case, (1):
1612 	 * The spec says that we must set IsRouter in the following cases:
1613 	 * - If lladdr exist, set IsRouter.  This means (1-5).
1614 	 * - If it is old entry (!newentry), set IsRouter.  This means (7).
1615 	 * So, based on the spec, in (1-5) and (7) cases we must set IsRouter.
1616 	 * A quetion arises for (1) case.  (1) case has no lladdr in the
1617 	 * neighbor cache, this is similar to (6).
1618 	 * This case is rare but we figured that we MUST NOT set IsRouter.
1619 	 *
1620 	 * newentry olladdr  lladdr  llchange	    NS  RS  RA	redir
1621 	 *							D R
1622 	 *	0	n	n	--	(1)	c   ?     s
1623 	 *	0	y	n	--	(2)	c   s     s
1624 	 *	0	n	y	--	(3)	c   s     s
1625 	 *	0	y	y	n	(4)	c   s     s
1626 	 *	0	y	y	y	(5)	c   s     s
1627 	 *	1	--	n	--	(6) c	c 	c s
1628 	 *	1	--	y	--	(7) c	c   s	c s
1629 	 *
1630 	 *					(c=clear s=set)
1631 	 */
1632 	switch (type & 0xff) {
1633 	case ND_NEIGHBOR_SOLICIT:
1634 		/*
1635 		 * New entry must have is_router flag cleared.
1636 		 */
1637 		if (is_newentry)	/* (6-7) */
1638 			ln->ln_router = 0;
1639 		break;
1640 	case ND_REDIRECT:
1641 		/*
1642 		 * If the icmp is a redirect to a better router, always set the
1643 		 * is_router flag.  Otherwise, if the entry is newly created,
1644 		 * clear the flag.  [RFC 2461, sec 8.3]
1645 		 */
1646 		if (code == ND_REDIRECT_ROUTER)
1647 			ln->ln_router = 1;
1648 		else if (is_newentry) /* (6-7) */
1649 			ln->ln_router = 0;
1650 		break;
1651 	case ND_ROUTER_SOLICIT:
1652 		/*
1653 		 * is_router flag must always be cleared.
1654 		 */
1655 		ln->ln_router = 0;
1656 		break;
1657 	case ND_ROUTER_ADVERT:
1658 		/*
1659 		 * Mark an entry with lladdr as a router.
1660 		 */
1661 		if ((!is_newentry && (olladdr || lladdr)) ||	/* (2-5) */
1662 		    (is_newentry && lladdr)) {			/* (7) */
1663 			ln->ln_router = 1;
1664 		}
1665 		break;
1666 	}
1667 
1668 	/*
1669 	 * When the link-layer address of a router changes, select the
1670 	 * best router again.  In particular, when the neighbor entry is newly
1671 	 * created, it might affect the selection policy.
1672 	 * Question: can we restrict the first condition to the "is_newentry"
1673 	 * case?
1674 	 * XXX: when we hear an RA from a new router with the link-layer
1675 	 * address option, defrouter_select() is called twice, since
1676 	 * defrtrlist_update called the function as well.  However, I believe
1677 	 * we can compromise the overhead, since it only happens the first
1678 	 * time.
1679 	 * XXX: although defrouter_select() should not have a bad effect
1680 	 * for those are not autoconfigured hosts, we explicitly avoid such
1681 	 * cases for safety.
1682 	 */
1683 	if (do_update && ln->ln_router && !ip6_forwarding && ip6_accept_rtadv)
1684 		defrouter_select();
1685 
1686 	return rt;
1687 }
1688 
1689 static void
1690 nd6_slowtimo(ignored_arg)
1691     void *ignored_arg;
1692 {
1693 	int s = splsoftnet();
1694 	struct nd_ifinfo *nd6if;
1695 	struct ifnet *ifp;
1696 
1697 	callout_reset(&nd6_slowtimo_ch, ND6_SLOWTIMER_INTERVAL * hz,
1698 	    nd6_slowtimo, NULL);
1699 	for (ifp = TAILQ_FIRST(&ifnet); ifp; ifp = TAILQ_NEXT(ifp, if_list))
1700 	{
1701 		nd6if = ND_IFINFO(ifp);
1702 		if (nd6if->basereachable && /* already initialized */
1703 		    (nd6if->recalctm -= ND6_SLOWTIMER_INTERVAL) <= 0) {
1704 			/*
1705 			 * Since reachable time rarely changes by router
1706 			 * advertisements, we SHOULD insure that a new random
1707 			 * value gets recomputed at least once every few hours.
1708 			 * (RFC 2461, 6.3.4)
1709 			 */
1710 			nd6if->recalctm = nd6_recalc_reachtm_interval;
1711 			nd6if->reachable = ND_COMPUTE_RTIME(nd6if->basereachable);
1712 		}
1713 	}
1714 	splx(s);
1715 }
1716 
1717 #define senderr(e) { error = (e); goto bad;}
1718 int
1719 nd6_output(ifp, origifp, m0, dst, rt0)
1720 	struct ifnet *ifp;
1721 	struct ifnet *origifp;
1722 	struct mbuf *m0;
1723 	struct sockaddr_in6 *dst;
1724 	struct rtentry *rt0;
1725 {
1726 	struct mbuf *m = m0;
1727 	struct rtentry *rt = rt0;
1728 	struct sockaddr_in6 *gw6 = NULL;
1729 	struct llinfo_nd6 *ln = NULL;
1730 	int error = 0;
1731 
1732 	if (IN6_IS_ADDR_MULTICAST(&dst->sin6_addr))
1733 		goto sendpkt;
1734 
1735 	if (nd6_need_cache(ifp) == 0)
1736 		goto sendpkt;
1737 
1738 	/*
1739 	 * next hop determination.  This routine is derived from ether_outpout.
1740 	 */
1741 	if (rt) {
1742 		if ((rt->rt_flags & RTF_UP) == 0) {
1743 			if ((rt0 = rt = rtalloc1((struct sockaddr *)dst,
1744 			    1)) != NULL)
1745 			{
1746 				rt->rt_refcnt--;
1747 				if (rt->rt_ifp != ifp)
1748 					senderr(EHOSTUNREACH);
1749 			} else
1750 				senderr(EHOSTUNREACH);
1751 		}
1752 
1753 		if (rt->rt_flags & RTF_GATEWAY) {
1754 			gw6 = (struct sockaddr_in6 *)rt->rt_gateway;
1755 
1756 			/*
1757 			 * We skip link-layer address resolution and NUD
1758 			 * if the gateway is not a neighbor from ND point
1759 			 * of view, regardless of the value of nd_ifinfo.flags.
1760 			 * The second condition is a bit tricky; we skip
1761 			 * if the gateway is our own address, which is
1762 			 * sometimes used to install a route to a p2p link.
1763 			 */
1764 			if (!nd6_is_addr_neighbor(gw6, ifp) ||
1765 			    in6ifa_ifpwithaddr(ifp, &gw6->sin6_addr)) {
1766 				/*
1767 				 * We allow this kind of tricky route only
1768 				 * when the outgoing interface is p2p.
1769 				 * XXX: we may need a more generic rule here.
1770 				 */
1771 				if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
1772 					senderr(EHOSTUNREACH);
1773 
1774 				goto sendpkt;
1775 			}
1776 
1777 			if (rt->rt_gwroute == 0)
1778 				goto lookup;
1779 			if (((rt = rt->rt_gwroute)->rt_flags & RTF_UP) == 0) {
1780 				rtfree(rt); rt = rt0;
1781 			lookup:
1782 				rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1);
1783 				if ((rt = rt->rt_gwroute) == 0)
1784 					senderr(EHOSTUNREACH);
1785 				/* the "G" test below also prevents rt == rt0 */
1786 				if ((rt->rt_flags & RTF_GATEWAY) ||
1787 				    (rt->rt_ifp != ifp)) {
1788 					rt->rt_refcnt--;
1789 					rt0->rt_gwroute = 0;
1790 					senderr(EHOSTUNREACH);
1791 				}
1792 			}
1793 		}
1794 	}
1795 
1796 	/*
1797 	 * Address resolution or Neighbor Unreachability Detection
1798 	 * for the next hop.
1799 	 * At this point, the destination of the packet must be a unicast
1800 	 * or an anycast address(i.e. not a multicast).
1801 	 */
1802 
1803 	/* Look up the neighbor cache for the nexthop */
1804 	if (rt && (rt->rt_flags & RTF_LLINFO) != 0)
1805 		ln = (struct llinfo_nd6 *)rt->rt_llinfo;
1806 	else {
1807 		/*
1808 		 * Since nd6_is_addr_neighbor() internally calls nd6_lookup(),
1809 		 * the condition below is not very efficient.  But we believe
1810 		 * it is tolerable, because this should be a rare case.
1811 		 */
1812 		if (nd6_is_addr_neighbor(dst, ifp) &&
1813 		    (rt = nd6_lookup(&dst->sin6_addr, 1, ifp)) != NULL)
1814 			ln = (struct llinfo_nd6 *)rt->rt_llinfo;
1815 	}
1816 	if (!ln || !rt) {
1817 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0 &&
1818 		    !(ND_IFINFO(ifp)->flags & ND6_IFF_PERFORMNUD)) {
1819 			log(LOG_DEBUG,
1820 			    "nd6_output: can't allocate llinfo for %s "
1821 			    "(ln=%p, rt=%p)\n",
1822 			    ip6_sprintf(&dst->sin6_addr), ln, rt);
1823 			senderr(EIO);	/* XXX: good error? */
1824 		}
1825 
1826 		goto sendpkt;	/* send anyway */
1827 	}
1828 
1829 	/* We don't have to do link-layer address resolution on a p2p link. */
1830 	if ((ifp->if_flags & IFF_POINTOPOINT) != 0 &&
1831 	    ln->ln_state < ND6_LLINFO_REACHABLE) {
1832 		ln->ln_state = ND6_LLINFO_STALE;
1833 		nd6_llinfo_settimer(ln, (long)nd6_gctimer * hz);
1834 	}
1835 
1836 	/*
1837 	 * The first time we send a packet to a neighbor whose entry is
1838 	 * STALE, we have to change the state to DELAY and a sets a timer to
1839 	 * expire in DELAY_FIRST_PROBE_TIME seconds to ensure do
1840 	 * neighbor unreachability detection on expiration.
1841 	 * (RFC 2461 7.3.3)
1842 	 */
1843 	if (ln->ln_state == ND6_LLINFO_STALE) {
1844 		ln->ln_asked = 0;
1845 		ln->ln_state = ND6_LLINFO_DELAY;
1846 		nd6_llinfo_settimer(ln, nd6_delay * hz);
1847 	}
1848 
1849 	/*
1850 	 * If the neighbor cache entry has a state other than INCOMPLETE
1851 	 * (i.e. its link-layer address is already resolved), just
1852 	 * send the packet.
1853 	 */
1854 	if (ln->ln_state > ND6_LLINFO_INCOMPLETE)
1855 		goto sendpkt;
1856 
1857 	/*
1858 	 * There is a neighbor cache entry, but no ethernet address
1859 	 * response yet.  Replace the held mbuf (if any) with this
1860 	 * latest one.
1861 	 */
1862 	if (ln->ln_state == ND6_LLINFO_NOSTATE)
1863 		ln->ln_state = ND6_LLINFO_INCOMPLETE;
1864 	if (ln->ln_hold)
1865 		m_freem(ln->ln_hold);
1866 	ln->ln_hold = m;
1867 	/*
1868 	 * If there has been no NS for the neighbor after entering the
1869 	 * INCOMPLETE state, send the first solicitation.
1870 	 */
1871 	if (!ND6_LLINFO_PERMANENT(ln) && ln->ln_asked == 0) {
1872 		ln->ln_asked++;
1873 		nd6_llinfo_settimer(ln,
1874 		    (long)ND_IFINFO(ifp)->retrans * hz / 1000);
1875 		nd6_ns_output(ifp, NULL, &dst->sin6_addr, ln, 0);
1876 	}
1877 	return (0);
1878 
1879   sendpkt:
1880 
1881 #ifdef IPSEC
1882 	/* clean ipsec history once it goes out of the node */
1883 	ipsec_delaux(m);
1884 #endif
1885 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
1886 		return ((*ifp->if_output)(origifp, m, (struct sockaddr *)dst,
1887 					 rt));
1888 	}
1889 	return ((*ifp->if_output)(ifp, m, (struct sockaddr *)dst, rt));
1890 
1891   bad:
1892 	if (m)
1893 		m_freem(m);
1894 	return (error);
1895 }
1896 #undef senderr
1897 
1898 int
1899 nd6_need_cache(ifp)
1900 	struct ifnet *ifp;
1901 {
1902 	/*
1903 	 * XXX: we currently do not make neighbor cache on any interface
1904 	 * other than ARCnet, Ethernet, FDDI and GIF.
1905 	 *
1906 	 * RFC2893 says:
1907 	 * - unidirectional tunnels needs no ND
1908 	 */
1909 	switch (ifp->if_type) {
1910 	case IFT_ARCNET:
1911 	case IFT_ETHER:
1912 	case IFT_FDDI:
1913 	case IFT_IEEE1394:
1914 	case IFT_GIF:		/* XXX need more cases? */
1915 		return (1);
1916 	default:
1917 		return (0);
1918 	}
1919 }
1920 
1921 int
1922 nd6_storelladdr(ifp, rt, m, dst, desten)
1923 	struct ifnet *ifp;
1924 	struct rtentry *rt;
1925 	struct mbuf *m;
1926 	struct sockaddr *dst;
1927 	u_char *desten;
1928 {
1929 	struct sockaddr_dl *sdl;
1930 
1931 	if (m->m_flags & M_MCAST) {
1932 		switch (ifp->if_type) {
1933 		case IFT_ETHER:
1934 		case IFT_FDDI:
1935 			ETHER_MAP_IPV6_MULTICAST(&SIN6(dst)->sin6_addr,
1936 						 desten);
1937 			return (1);
1938 		case IFT_IEEE1394:
1939 			bcopy(ifp->if_broadcastaddr, desten, ifp->if_addrlen);
1940 			return (1);
1941 		case IFT_ARCNET:
1942 			*desten = 0;
1943 			return (1);
1944 		default:
1945 			m_freem(m);
1946 			return (0);
1947 		}
1948 	}
1949 
1950 	if (rt == NULL) {
1951 		/* this could happen, if we could not allocate memory */
1952 		m_freem(m);
1953 		return (0);
1954 	}
1955 	if (rt->rt_gateway->sa_family != AF_LINK) {
1956 		printf("nd6_storelladdr: something odd happens\n");
1957 		m_freem(m);
1958 		return (0);
1959 	}
1960 	sdl = SDL(rt->rt_gateway);
1961 	if (sdl->sdl_alen == 0) {
1962 		/* this should be impossible, but we bark here for debugging */
1963 		printf("nd6_storelladdr: sdl_alen == 0, dst=%s, if=%s\n",
1964 		    ip6_sprintf(&SIN6(dst)->sin6_addr), if_name(ifp));
1965 		m_freem(m);
1966 		return (0);
1967 	}
1968 
1969 	bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
1970 	return (1);
1971 }
1972 
1973 int
1974 nd6_sysctl(name, oldp, oldlenp, newp, newlen)
1975 	int name;
1976 	void *oldp;	/* syscall arg, need copyout */
1977 	size_t *oldlenp;
1978 	void *newp;	/* syscall arg, need copyin */
1979 	size_t newlen;
1980 {
1981 	void *p;
1982 	size_t ol;
1983 	int error;
1984 
1985 	error = 0;
1986 
1987 	if (newp)
1988 		return EPERM;
1989 	if (oldp && !oldlenp)
1990 		return EINVAL;
1991 	ol = oldlenp ? *oldlenp : 0;
1992 
1993 	if (oldp) {
1994 		p = malloc(*oldlenp, M_TEMP, M_WAITOK);
1995 		if (!p)
1996 			return ENOMEM;
1997 	} else
1998 		p = NULL;
1999 	switch (name) {
2000 	case ICMPV6CTL_ND6_DRLIST:
2001 		error = fill_drlist(p, oldlenp, ol);
2002 		if (!error && p && oldp)
2003 			error = copyout(p, oldp, *oldlenp);
2004 		break;
2005 
2006 	case ICMPV6CTL_ND6_PRLIST:
2007 		error = fill_prlist(p, oldlenp, ol);
2008 		if (!error && p && oldp)
2009 			error = copyout(p, oldp, *oldlenp);
2010 		break;
2011 
2012 	default:
2013 		error = ENOPROTOOPT;
2014 		break;
2015 	}
2016 	if (p)
2017 		free(p, M_TEMP);
2018 
2019 	return (error);
2020 }
2021 
2022 static int
2023 fill_drlist(oldp, oldlenp, ol)
2024 	void *oldp;
2025 	size_t *oldlenp, ol;
2026 {
2027 	int error = 0, s;
2028 	struct in6_defrouter *d = NULL, *de = NULL;
2029 	struct nd_defrouter *dr;
2030 	size_t l;
2031 
2032 	s = splsoftnet();
2033 
2034 	if (oldp) {
2035 		d = (struct in6_defrouter *)oldp;
2036 		de = (struct in6_defrouter *)((caddr_t)oldp + *oldlenp);
2037 	}
2038 	l = 0;
2039 
2040 	for (dr = TAILQ_FIRST(&nd_defrouter); dr;
2041 	     dr = TAILQ_NEXT(dr, dr_entry)) {
2042 
2043 		if (oldp && d + 1 <= de) {
2044 			bzero(d, sizeof(*d));
2045 			d->rtaddr.sin6_family = AF_INET6;
2046 			d->rtaddr.sin6_len = sizeof(struct sockaddr_in6);
2047 			d->rtaddr.sin6_addr = dr->rtaddr;
2048 			if (sa6_recoverscope(&d->rtaddr)) {
2049 				log(LOG_ERR,
2050 				    "scope error in router list (%s)\n",
2051 				    ip6_sprintf(&d->rtaddr.sin6_addr));
2052 				/* XXX: press on... */
2053 			}
2054 			d->flags = dr->flags;
2055 			d->rtlifetime = dr->rtlifetime;
2056 			d->expire = dr->expire;
2057 			d->if_index = dr->ifp->if_index;
2058 		}
2059 
2060 		l += sizeof(*d);
2061 		if (d)
2062 			d++;
2063 	}
2064 
2065 	if (oldp) {
2066 		*oldlenp = l;	/* (caddr_t)d - (caddr_t)oldp */
2067 		if (l > ol)
2068 			error = ENOMEM;
2069 	} else
2070 		*oldlenp = l;
2071 
2072 	splx(s);
2073 
2074 	return (error);
2075 }
2076 
2077 static int
2078 fill_prlist(oldp, oldlenp, ol)
2079 	void *oldp;
2080 	size_t *oldlenp, ol;
2081 {
2082 	int error = 0, s;
2083 	struct nd_prefix *pr;
2084 	struct in6_prefix *p = NULL;
2085 	struct in6_prefix *pe = NULL;
2086 	size_t l;
2087 
2088 	s = splsoftnet();
2089 
2090 	if (oldp) {
2091 		p = (struct in6_prefix *)oldp;
2092 		pe = (struct in6_prefix *)((caddr_t)oldp + *oldlenp);
2093 	}
2094 	l = 0;
2095 
2096 	for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
2097 		u_short advrtrs;
2098 		size_t advance;
2099 		struct sockaddr_in6 *sin6;
2100 		struct sockaddr_in6 *s6;
2101 		struct nd_pfxrouter *pfr;
2102 
2103 		if (oldp && p + 1 <= pe)
2104 		{
2105 			bzero(p, sizeof(*p));
2106 			sin6 = (struct sockaddr_in6 *)(p + 1);
2107 
2108 			p->prefix = pr->ndpr_prefix;
2109 			if (sa6_recoverscope(&p->prefix)) {
2110 				log(LOG_ERR,
2111 				    "scope error in prefix list (%s)\n",
2112 				    ip6_sprintf(&p->prefix.sin6_addr));
2113 				/* XXX: press on... */
2114 			}
2115 			p->raflags = pr->ndpr_raf;
2116 			p->prefixlen = pr->ndpr_plen;
2117 			p->vltime = pr->ndpr_vltime;
2118 			p->pltime = pr->ndpr_pltime;
2119 			p->if_index = pr->ndpr_ifp->if_index;
2120 			if (pr->ndpr_vltime == ND6_INFINITE_LIFETIME)
2121 				p->expire = 0;
2122 			else {
2123 				time_t maxexpire;
2124 
2125 				/* XXX: we assume time_t is signed. */
2126 				maxexpire = (-1) &
2127 					~(1 << ((sizeof(maxexpire) * 8) - 1));
2128 				if (pr->ndpr_vltime <
2129 				    maxexpire - pr->ndpr_lastupdate) {
2130 					p->expire = pr->ndpr_lastupdate +
2131 						pr->ndpr_vltime;
2132 				} else
2133 					p->expire = maxexpire;
2134 			}
2135 			p->refcnt = pr->ndpr_refcnt;
2136 			p->flags = pr->ndpr_stateflags;
2137 			p->origin = PR_ORIG_RA;
2138 			advrtrs = 0;
2139 			for (pfr = pr->ndpr_advrtrs.lh_first; pfr;
2140 			     pfr = pfr->pfr_next) {
2141 				if ((void *)&sin6[advrtrs + 1] > (void *)pe) {
2142 					advrtrs++;
2143 					continue;
2144 				}
2145 				s6 = &sin6[advrtrs];
2146 				s6->sin6_family = AF_INET6;
2147 				s6->sin6_len = sizeof(struct sockaddr_in6);
2148 				s6->sin6_addr = pfr->router->rtaddr;
2149 				s6->sin6_scope_id = 0;
2150 				if (sa6_recoverscope(s6)) {
2151 					log(LOG_ERR,
2152 					    "scope error in "
2153 					    "prefix list (%s)\n",
2154 					    ip6_sprintf(&pfr->router->rtaddr));
2155 				}
2156 				advrtrs++;
2157 			}
2158 			p->advrtrs = advrtrs;
2159 		}
2160 		else {
2161 			advrtrs = 0;
2162 			for (pfr = pr->ndpr_advrtrs.lh_first; pfr;
2163 			     pfr = pfr->pfr_next)
2164 				advrtrs++;
2165 		}
2166 
2167 		advance = sizeof(*p) + sizeof(*sin6) * advrtrs;
2168 		l += advance;
2169 		if (p)
2170 			p = (struct in6_prefix *)((caddr_t)p + advance);
2171 	}
2172 
2173 	if (oldp) {
2174 		*oldlenp = l;	/* (caddr_t)d - (caddr_t)oldp */
2175 		if (l > ol)
2176 			error = ENOMEM;
2177 	} else
2178 		*oldlenp = l;
2179 
2180 	splx(s);
2181 
2182 	return (error);
2183 }
2184