nd6_nbr.c revision 122062
1/*	$FreeBSD: head/sys/netinet6/nd6_nbr.c 122062 2003-11-04 16:02:05Z ume $	*/
2/*	$KAME: nd6_nbr.c,v 1.86 2002/01/21 02:33:04 jinmei 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 "opt_inet.h"
34#include "opt_inet6.h"
35#include "opt_ipsec.h"
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/malloc.h>
40#include <sys/mbuf.h>
41#include <sys/socket.h>
42#include <sys/sockio.h>
43#include <sys/time.h>
44#include <sys/kernel.h>
45#include <sys/errno.h>
46#include <sys/syslog.h>
47#include <sys/queue.h>
48#include <sys/callout.h>
49
50#include <net/if.h>
51#include <net/if_types.h>
52#include <net/if_dl.h>
53#include <net/route.h>
54
55#include <netinet/in.h>
56#include <netinet/in_var.h>
57#include <netinet6/in6_var.h>
58#include <netinet/ip6.h>
59#include <netinet6/ip6_var.h>
60#include <netinet6/nd6.h>
61#include <netinet/icmp6.h>
62
63#ifdef IPSEC
64#include <netinet6/ipsec.h>
65#ifdef INET6
66#include <netinet6/ipsec6.h>
67#endif
68#endif
69
70#include <net/net_osdep.h>
71
72#define SDL(s) ((struct sockaddr_dl *)s)
73
74struct dadq;
75static struct dadq *nd6_dad_find __P((struct ifaddr *));
76static void nd6_dad_starttimer __P((struct dadq *, int));
77static void nd6_dad_stoptimer __P((struct dadq *));
78static void nd6_dad_timer __P((struct ifaddr *));
79static void nd6_dad_ns_output __P((struct dadq *, struct ifaddr *));
80static void nd6_dad_ns_input __P((struct ifaddr *));
81static void nd6_dad_na_input __P((struct ifaddr *));
82
83static int dad_ignore_ns = 0;	/* ignore NS in DAD - specwise incorrect*/
84static int dad_maxtry = 15;	/* max # of *tries* to transmit DAD packet */
85
86/*
87 * Input a Neighbor Solicitation Message.
88 *
89 * Based on RFC 2461
90 * Based on RFC 2462 (duplicated address detection)
91 */
92void
93nd6_ns_input(m, off, icmp6len)
94	struct mbuf *m;
95	int off, icmp6len;
96{
97	struct ifnet *ifp = m->m_pkthdr.rcvif;
98	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
99	struct nd_neighbor_solicit *nd_ns;
100	struct in6_addr saddr6 = ip6->ip6_src;
101	struct in6_addr daddr6 = ip6->ip6_dst;
102	struct in6_addr taddr6;
103	struct in6_addr myaddr6;
104	char *lladdr = NULL;
105	struct ifaddr *ifa;
106	int lladdrlen = 0;
107	int anycast = 0, proxy = 0, tentative = 0;
108	int tlladdr;
109	union nd_opts ndopts;
110	struct sockaddr_dl *proxydl = NULL;
111
112#ifndef PULLDOWN_TEST
113	IP6_EXTHDR_CHECK(m, off, icmp6len,);
114	nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
115#else
116	IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
117	if (nd_ns == NULL) {
118		icmp6stat.icp6s_tooshort++;
119		return;
120	}
121#endif
122	ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
123	taddr6 = nd_ns->nd_ns_target;
124
125	if (ip6->ip6_hlim != 255) {
126		nd6log((LOG_ERR,
127		    "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
128		    ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
129		    ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
130		goto bad;
131	}
132
133	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
134		/* dst has to be solicited node multicast address. */
135		if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL &&
136		    /* don't check ifindex portion */
137		    daddr6.s6_addr32[1] == 0 &&
138		    daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE &&
139		    daddr6.s6_addr8[12] == 0xff) {
140			; /* good */
141		} else {
142			nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
143			    "(wrong ip6 dst)\n"));
144			goto bad;
145		}
146	}
147
148	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
149		nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
150		goto bad;
151	}
152
153	if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
154		taddr6.s6_addr16[1] = htons(ifp->if_index);
155
156	icmp6len -= sizeof(*nd_ns);
157	nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
158	if (nd6_options(&ndopts) < 0) {
159		nd6log((LOG_INFO,
160		    "nd6_ns_input: invalid ND option, ignored\n"));
161		/* nd6_options have incremented stats */
162		goto freeit;
163	}
164
165	if (ndopts.nd_opts_src_lladdr) {
166		lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
167		lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
168	}
169
170	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
171		nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
172		    "(link-layer address option)\n"));
173		goto bad;
174	}
175
176	/*
177	 * Attaching target link-layer address to the NA?
178	 * (RFC 2461 7.2.4)
179	 *
180	 * NS IP dst is unicast/anycast			MUST NOT add
181	 * NS IP dst is solicited-node multicast	MUST add
182	 *
183	 * In implementation, we add target link-layer address by default.
184	 * We do not add one in MUST NOT cases.
185	 */
186#if 0 /* too much! */
187	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &daddr6);
188	if (ifa && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST))
189		tlladdr = 0;
190	else
191#endif
192	if (!IN6_IS_ADDR_MULTICAST(&daddr6))
193		tlladdr = 0;
194	else
195		tlladdr = 1;
196
197	/*
198	 * Target address (taddr6) must be either:
199	 * (1) Valid unicast/anycast address for my receiving interface,
200	 * (2) Unicast address for which I'm offering proxy service, or
201	 * (3) "tentative" address on which DAD is being performed.
202	 */
203	/* (1) and (3) check. */
204	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
205
206	/* (2) check. */
207	if (!ifa) {
208		struct rtentry *rt;
209		struct sockaddr_in6 tsin6;
210		int need_proxy;
211
212		bzero(&tsin6, sizeof tsin6);
213		tsin6.sin6_len = sizeof(struct sockaddr_in6);
214		tsin6.sin6_family = AF_INET6;
215		tsin6.sin6_addr = taddr6;
216
217		rt = rtalloc1((struct sockaddr *)&tsin6, 0, 0);
218		need_proxy = (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 &&
219		    rt->rt_gateway->sa_family == AF_LINK);
220		if (rt)
221			rtfree(rt);
222		if (need_proxy) {
223			/*
224			 * proxy NDP for single entry
225			 */
226			ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
227				IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
228			if (ifa) {
229				proxy = 1;
230				proxydl = SDL(rt->rt_gateway);
231			}
232		}
233	}
234	if (!ifa) {
235		/*
236		 * We've got an NS packet, and we don't have that adddress
237		 * assigned for us.  We MUST silently ignore it.
238		 * See RFC2461 7.2.3.
239		 */
240		goto freeit;
241	}
242	myaddr6 = *IFA_IN6(ifa);
243	anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
244	tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
245	if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
246		goto freeit;
247
248	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
249		nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
250		    "(if %d, NS packet %d)\n",
251		    ip6_sprintf(&taddr6),
252		    ifp->if_addrlen, lladdrlen - 2));
253		goto bad;
254	}
255
256	if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
257		nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
258		    ip6_sprintf(&saddr6)));
259		goto freeit;
260	}
261
262	/*
263	 * We have neighbor solicitation packet, with target address equals to
264	 * one of my tentative address.
265	 *
266	 * src addr	how to process?
267	 * ---		---
268	 * multicast	of course, invalid (rejected in ip6_input)
269	 * unicast	somebody is doing address resolution -> ignore
270	 * unspec	dup address detection
271	 *
272	 * The processing is defined in RFC 2462.
273	 */
274	if (tentative) {
275		/*
276		 * If source address is unspecified address, it is for
277		 * duplicated address detection.
278		 *
279		 * If not, the packet is for addess resolution;
280		 * silently ignore it.
281		 */
282		if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
283			nd6_dad_ns_input(ifa);
284
285		goto freeit;
286	}
287
288	/*
289	 * If the source address is unspecified address, entries must not
290	 * be created or updated.
291	 * It looks that sender is performing DAD.  Output NA toward
292	 * all-node multicast address, to tell the sender that I'm using
293	 * the address.
294	 * S bit ("solicited") must be zero.
295	 */
296	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
297		saddr6 = in6addr_linklocal_allnodes;
298		saddr6.s6_addr16[1] = htons(ifp->if_index);
299		nd6_na_output(ifp, &saddr6, &taddr6,
300		    ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
301		    (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
302		    tlladdr, (struct sockaddr *)proxydl);
303		goto freeit;
304	}
305
306	nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen,
307	    ND_NEIGHBOR_SOLICIT, 0);
308
309	nd6_na_output(ifp, &saddr6, &taddr6,
310	    ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
311	    (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED,
312	    tlladdr, (struct sockaddr *)proxydl);
313 freeit:
314	m_freem(m);
315	return;
316
317 bad:
318	nd6log((LOG_ERR, "nd6_ns_input: src=%s\n", ip6_sprintf(&saddr6)));
319	nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n", ip6_sprintf(&daddr6)));
320	nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n", ip6_sprintf(&taddr6)));
321	icmp6stat.icp6s_badns++;
322	m_freem(m);
323}
324
325/*
326 * Output a Neighbor Solicitation Message. Caller specifies:
327 *	- ICMP6 header source IP6 address
328 *	- ND6 header target IP6 address
329 *	- ND6 header source datalink address
330 *
331 * Based on RFC 2461
332 * Based on RFC 2462 (duplicated address detection)
333 */
334void
335nd6_ns_output(ifp, daddr6, taddr6, ln, dad)
336	struct ifnet *ifp;
337	const struct in6_addr *daddr6, *taddr6;
338	struct llinfo_nd6 *ln;	/* for source address determination */
339	int dad;	/* duplicated address detection */
340{
341	struct mbuf *m;
342	struct ip6_hdr *ip6;
343	struct nd_neighbor_solicit *nd_ns;
344	struct in6_ifaddr *ia = NULL;
345	struct ip6_moptions im6o;
346	int icmp6len;
347	int maxlen;
348	caddr_t mac;
349	struct ifnet *outif = NULL;
350
351	if (IN6_IS_ADDR_MULTICAST(taddr6))
352		return;
353
354	/* estimate the size of message */
355	maxlen = sizeof(*ip6) + sizeof(*nd_ns);
356	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
357	if (max_linkhdr + maxlen >= MCLBYTES) {
358#ifdef DIAGNOSTIC
359		printf("nd6_ns_output: max_linkhdr + maxlen >= MCLBYTES "
360		    "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
361#endif
362		return;
363	}
364
365	MGETHDR(m, M_DONTWAIT, MT_DATA);
366	if (m && max_linkhdr + maxlen >= MHLEN) {
367		MCLGET(m, M_DONTWAIT);
368		if ((m->m_flags & M_EXT) == 0) {
369			m_free(m);
370			m = NULL;
371		}
372	}
373	if (m == NULL)
374		return;
375	m->m_pkthdr.rcvif = NULL;
376
377	if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
378		m->m_flags |= M_MCAST;
379		im6o.im6o_multicast_ifp = ifp;
380		im6o.im6o_multicast_hlim = 255;
381		im6o.im6o_multicast_loop = 0;
382	}
383
384	icmp6len = sizeof(*nd_ns);
385	m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
386	m->m_data += max_linkhdr;	/* or MH_ALIGN() equivalent? */
387
388	/* fill neighbor solicitation packet */
389	ip6 = mtod(m, struct ip6_hdr *);
390	ip6->ip6_flow = 0;
391	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
392	ip6->ip6_vfc |= IPV6_VERSION;
393	/* ip6->ip6_plen will be set later */
394	ip6->ip6_nxt = IPPROTO_ICMPV6;
395	ip6->ip6_hlim = 255;
396	if (daddr6)
397		ip6->ip6_dst = *daddr6;
398	else {
399		ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
400		ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
401		ip6->ip6_dst.s6_addr32[1] = 0;
402		ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
403		ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
404		ip6->ip6_dst.s6_addr8[12] = 0xff;
405	}
406	if (!dad) {
407		/*
408		 * RFC2461 7.2.2:
409		 * "If the source address of the packet prompting the
410		 * solicitation is the same as one of the addresses assigned
411		 * to the outgoing interface, that address SHOULD be placed
412		 * in the IP Source Address of the outgoing solicitation.
413		 * Otherwise, any one of the addresses assigned to the
414		 * interface should be used."
415		 *
416		 * We use the source address for the prompting packet
417		 * (saddr6), if:
418		 * - saddr6 is given from the caller (by giving "ln"), and
419		 * - saddr6 belongs to the outgoing interface.
420		 * Otherwise, we perform a scope-wise match.
421		 */
422		struct ip6_hdr *hip6;		/* hold ip6 */
423		struct in6_addr *saddr6;
424
425		if (ln && ln->ln_hold) {
426			hip6 = mtod(ln->ln_hold, struct ip6_hdr *);
427			/* XXX pullup? */
428			if (sizeof(*hip6) < ln->ln_hold->m_len)
429				saddr6 = &hip6->ip6_src;
430			else
431				saddr6 = NULL;
432		} else
433			saddr6 = NULL;
434		if (saddr6 && in6ifa_ifpwithaddr(ifp, saddr6))
435			bcopy(saddr6, &ip6->ip6_src, sizeof(*saddr6));
436		else {
437			ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
438			if (ia == NULL) {
439				m_freem(m);
440				return;
441			}
442			ip6->ip6_src = ia->ia_addr.sin6_addr;
443		}
444	} else {
445		/*
446		 * Source address for DAD packet must always be IPv6
447		 * unspecified address. (0::0)
448		 */
449		bzero(&ip6->ip6_src, sizeof(ip6->ip6_src));
450	}
451	nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1);
452	nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT;
453	nd_ns->nd_ns_code = 0;
454	nd_ns->nd_ns_reserved = 0;
455	nd_ns->nd_ns_target = *taddr6;
456	in6_clearscope(&nd_ns->nd_ns_target); /* XXX */
457
458	/*
459	 * Add source link-layer address option.
460	 *
461	 *				spec		implementation
462	 *				---		---
463	 * DAD packet			MUST NOT	do not add the option
464	 * there's no link layer address:
465	 *				impossible	do not add the option
466	 * there's link layer address:
467	 *	Multicast NS		MUST add one	add the option
468	 *	Unicast NS		SHOULD add one	add the option
469	 */
470	if (!dad && (mac = nd6_ifptomac(ifp))) {
471		int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
472		struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
473		/* 8 byte alignments... */
474		optlen = (optlen + 7) & ~7;
475
476		m->m_pkthdr.len += optlen;
477		m->m_len += optlen;
478		icmp6len += optlen;
479		bzero((caddr_t)nd_opt, optlen);
480		nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
481		nd_opt->nd_opt_len = optlen >> 3;
482		bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
483	}
484
485	ip6->ip6_plen = htons((u_short)icmp6len);
486	nd_ns->nd_ns_cksum = 0;
487	nd_ns->nd_ns_cksum =
488	    in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
489
490#ifdef IPSEC
491	/* Don't lookup socket */
492	(void)ipsec_setsocket(m, NULL);
493#endif
494	ip6_output(m, NULL, NULL, dad ? IPV6_DADOUTPUT : 0, &im6o, &outif, NULL);
495	if (outif) {
496		icmp6_ifstat_inc(outif, ifs6_out_msg);
497		icmp6_ifstat_inc(outif, ifs6_out_neighborsolicit);
498	}
499	icmp6stat.icp6s_outhist[ND_NEIGHBOR_SOLICIT]++;
500}
501
502/*
503 * Neighbor advertisement input handling.
504 *
505 * Based on RFC 2461
506 * Based on RFC 2462 (duplicated address detection)
507 *
508 * the following items are not implemented yet:
509 * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
510 * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
511 */
512void
513nd6_na_input(m, off, icmp6len)
514	struct mbuf *m;
515	int off, icmp6len;
516{
517	struct ifnet *ifp = m->m_pkthdr.rcvif;
518	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
519	struct nd_neighbor_advert *nd_na;
520	struct in6_addr daddr6 = ip6->ip6_dst;
521	struct in6_addr taddr6;
522	int flags;
523	int is_router;
524	int is_solicited;
525	int is_override;
526	char *lladdr = NULL;
527	int lladdrlen = 0;
528	struct ifaddr *ifa;
529	struct llinfo_nd6 *ln;
530	struct rtentry *rt;
531	struct sockaddr_dl *sdl;
532	union nd_opts ndopts;
533
534	if (ip6->ip6_hlim != 255) {
535		nd6log((LOG_ERR,
536		    "nd6_na_input: invalid hlim (%d) from %s to %s on %s\n",
537		    ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
538		    ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
539		goto bad;
540	}
541
542#ifndef PULLDOWN_TEST
543	IP6_EXTHDR_CHECK(m, off, icmp6len,);
544	nd_na = (struct nd_neighbor_advert *)((caddr_t)ip6 + off);
545#else
546	IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len);
547	if (nd_na == NULL) {
548		icmp6stat.icp6s_tooshort++;
549		return;
550	}
551#endif
552	taddr6 = nd_na->nd_na_target;
553	flags = nd_na->nd_na_flags_reserved;
554	is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
555	is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
556	is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
557
558	if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
559		taddr6.s6_addr16[1] = htons(ifp->if_index);
560
561	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
562		nd6log((LOG_ERR,
563		    "nd6_na_input: invalid target address %s\n",
564		    ip6_sprintf(&taddr6)));
565		goto bad;
566	}
567	if (IN6_IS_ADDR_MULTICAST(&daddr6))
568		if (is_solicited) {
569			nd6log((LOG_ERR,
570			    "nd6_na_input: a solicited adv is multicasted\n"));
571			goto bad;
572		}
573
574	icmp6len -= sizeof(*nd_na);
575	nd6_option_init(nd_na + 1, icmp6len, &ndopts);
576	if (nd6_options(&ndopts) < 0) {
577		nd6log((LOG_INFO,
578		    "nd6_na_input: invalid ND option, ignored\n"));
579		/* nd6_options have incremented stats */
580		goto freeit;
581	}
582
583	if (ndopts.nd_opts_tgt_lladdr) {
584		lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
585		lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
586	}
587
588	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
589
590	/*
591	 * Target address matches one of my interface address.
592	 *
593	 * If my address is tentative, this means that there's somebody
594	 * already using the same address as mine.  This indicates DAD failure.
595	 * This is defined in RFC 2462.
596	 *
597	 * Otherwise, process as defined in RFC 2461.
598	 */
599	if (ifa
600	 && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
601		nd6_dad_na_input(ifa);
602		goto freeit;
603	}
604
605	/* Just for safety, maybe unnecessary. */
606	if (ifa) {
607		log(LOG_ERR,
608		    "nd6_na_input: duplicate IP6 address %s\n",
609		    ip6_sprintf(&taddr6));
610		goto freeit;
611	}
612
613	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
614		nd6log((LOG_INFO, "nd6_na_input: lladdrlen mismatch for %s "
615		    "(if %d, NA packet %d)\n", ip6_sprintf(&taddr6),
616		    ifp->if_addrlen, lladdrlen - 2));
617		goto bad;
618	}
619
620	/*
621	 * If no neighbor cache entry is found, NA SHOULD silently be
622	 * discarded.
623	 */
624	rt = nd6_lookup(&taddr6, 0, ifp);
625	if ((rt == NULL) ||
626	   ((ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) ||
627	   ((sdl = SDL(rt->rt_gateway)) == NULL))
628		goto freeit;
629
630	if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
631		/*
632		 * If the link-layer has address, and no lladdr option came,
633		 * discard the packet.
634		 */
635		if (ifp->if_addrlen && !lladdr)
636			goto freeit;
637
638		/*
639		 * Record link-layer address, and update the state.
640		 */
641		sdl->sdl_alen = ifp->if_addrlen;
642		bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
643		if (is_solicited) {
644			ln->ln_state = ND6_LLINFO_REACHABLE;
645			ln->ln_byhint = 0;
646			if (ln->ln_expire) {
647				ln->ln_expire = time_second +
648				    ND_IFINFO(rt->rt_ifp)->reachable;
649			}
650		} else {
651			ln->ln_state = ND6_LLINFO_STALE;
652			ln->ln_expire = time_second + nd6_gctimer;
653		}
654		if ((ln->ln_router = is_router) != 0) {
655			/*
656			 * This means a router's state has changed from
657			 * non-reachable to probably reachable, and might
658			 * affect the status of associated prefixes..
659			 */
660			pfxlist_onlink_check();
661		}
662	} else {
663		int llchange;
664
665		/*
666		 * Check if the link-layer address has changed or not.
667		 */
668		if (!lladdr)
669			llchange = 0;
670		else {
671			if (sdl->sdl_alen) {
672				if (bcmp(lladdr, LLADDR(sdl), ifp->if_addrlen))
673					llchange = 1;
674				else
675					llchange = 0;
676			} else
677				llchange = 1;
678		}
679
680		/*
681		 * This is VERY complex.  Look at it with care.
682		 *
683		 * override solicit lladdr llchange	action
684		 *					(L: record lladdr)
685		 *
686		 *	0	0	n	--	(2c)
687		 *	0	0	y	n	(2b) L
688		 *	0	0	y	y	(1)    REACHABLE->STALE
689		 *	0	1	n	--	(2c)   *->REACHABLE
690		 *	0	1	y	n	(2b) L *->REACHABLE
691		 *	0	1	y	y	(1)    REACHABLE->STALE
692		 *	1	0	n	--	(2a)
693		 *	1	0	y	n	(2a) L
694		 *	1	0	y	y	(2a) L *->STALE
695		 *	1	1	n	--	(2a)   *->REACHABLE
696		 *	1	1	y	n	(2a) L *->REACHABLE
697		 *	1	1	y	y	(2a) L *->REACHABLE
698		 */
699		if (!is_override && (lladdr && llchange)) {	   /* (1) */
700			/*
701			 * If state is REACHABLE, make it STALE.
702			 * no other updates should be done.
703			 */
704			if (ln->ln_state == ND6_LLINFO_REACHABLE) {
705				ln->ln_state = ND6_LLINFO_STALE;
706				ln->ln_expire = time_second + nd6_gctimer;
707			}
708			goto freeit;
709		} else if (is_override				   /* (2a) */
710			|| (!is_override && (lladdr && !llchange)) /* (2b) */
711			|| !lladdr) {				   /* (2c) */
712			/*
713			 * Update link-local address, if any.
714			 */
715			if (lladdr) {
716				sdl->sdl_alen = ifp->if_addrlen;
717				bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
718			}
719
720			/*
721			 * If solicited, make the state REACHABLE.
722			 * If not solicited and the link-layer address was
723			 * changed, make it STALE.
724			 */
725			if (is_solicited) {
726				ln->ln_state = ND6_LLINFO_REACHABLE;
727				ln->ln_byhint = 0;
728				if (ln->ln_expire) {
729					ln->ln_expire = time_second +
730					    ND_IFINFO(ifp)->reachable;
731				}
732			} else {
733				if (lladdr && llchange) {
734					ln->ln_state = ND6_LLINFO_STALE;
735					ln->ln_expire = time_second + nd6_gctimer;
736				}
737			}
738		}
739
740		if (ln->ln_router && !is_router) {
741			/*
742			 * The peer dropped the router flag.
743			 * Remove the sender from the Default Router List and
744			 * update the Destination Cache entries.
745			 */
746			struct nd_defrouter *dr;
747			struct in6_addr *in6;
748			int s;
749
750			in6 = &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr;
751
752			/*
753			 * Lock to protect the default router list.
754			 * XXX: this might be unnecessary, since this function
755			 * is only called under the network software interrupt
756			 * context.  However, we keep it just for safety.
757			 */
758			s = splnet();
759			dr = defrouter_lookup(in6, rt->rt_ifp);
760			if (dr)
761				defrtrlist_del(dr);
762			else if (!ip6_forwarding && ip6_accept_rtadv) {
763				/*
764				 * Even if the neighbor is not in the default
765				 * router list, the neighbor may be used
766				 * as a next hop for some destinations
767				 * (e.g. redirect case). So we must
768				 * call rt6_flush explicitly.
769				 */
770				rt6_flush(&ip6->ip6_src, rt->rt_ifp);
771			}
772			splx(s);
773		}
774		ln->ln_router = is_router;
775	}
776	rt->rt_flags &= ~RTF_REJECT;
777	ln->ln_asked = 0;
778	if (ln->ln_hold) {
779		/*
780		 * we assume ifp is not a loopback here, so just set the 2nd
781		 * argument as the 1st one.
782		 */
783		nd6_output(ifp, ifp, ln->ln_hold,
784			   (struct sockaddr_in6 *)rt_key(rt), rt);
785		ln->ln_hold = NULL;
786	}
787
788 freeit:
789	m_freem(m);
790	return;
791
792 bad:
793	icmp6stat.icp6s_badna++;
794	m_freem(m);
795}
796
797/*
798 * Neighbor advertisement output handling.
799 *
800 * Based on RFC 2461
801 *
802 * the following items are not implemented yet:
803 * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
804 * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
805 */
806void
807nd6_na_output(ifp, daddr6, taddr6, flags, tlladdr, sdl0)
808	struct ifnet *ifp;
809	const struct in6_addr *daddr6, *taddr6;
810	u_long flags;
811	int tlladdr;		/* 1 if include target link-layer address */
812	struct sockaddr *sdl0;	/* sockaddr_dl (= proxy NA) or NULL */
813{
814	struct mbuf *m;
815	struct ip6_hdr *ip6;
816	struct nd_neighbor_advert *nd_na;
817	struct in6_ifaddr *ia = NULL;
818	struct ip6_moptions im6o;
819	int icmp6len;
820	int maxlen;
821	caddr_t mac = NULL;
822	struct ifnet *outif = NULL;
823
824	/* estimate the size of message */
825	maxlen = sizeof(*ip6) + sizeof(*nd_na);
826	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
827	if (max_linkhdr + maxlen >= MCLBYTES) {
828#ifdef DIAGNOSTIC
829		printf("nd6_na_output: max_linkhdr + maxlen >= MCLBYTES "
830		    "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
831#endif
832		return;
833	}
834
835	MGETHDR(m, M_DONTWAIT, MT_DATA);
836	if (m && max_linkhdr + maxlen >= MHLEN) {
837		MCLGET(m, M_DONTWAIT);
838		if ((m->m_flags & M_EXT) == 0) {
839			m_free(m);
840			m = NULL;
841		}
842	}
843	if (m == NULL)
844		return;
845	m->m_pkthdr.rcvif = NULL;
846
847	if (IN6_IS_ADDR_MULTICAST(daddr6)) {
848		m->m_flags |= M_MCAST;
849		im6o.im6o_multicast_ifp = ifp;
850		im6o.im6o_multicast_hlim = 255;
851		im6o.im6o_multicast_loop = 0;
852	}
853
854	icmp6len = sizeof(*nd_na);
855	m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
856	m->m_data += max_linkhdr;	/* or MH_ALIGN() equivalent? */
857
858	/* fill neighbor advertisement packet */
859	ip6 = mtod(m, struct ip6_hdr *);
860	ip6->ip6_flow = 0;
861	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
862	ip6->ip6_vfc |= IPV6_VERSION;
863	ip6->ip6_nxt = IPPROTO_ICMPV6;
864	ip6->ip6_hlim = 255;
865	if (IN6_IS_ADDR_UNSPECIFIED(daddr6)) {
866		/* reply to DAD */
867		ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
868		ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
869		ip6->ip6_dst.s6_addr32[1] = 0;
870		ip6->ip6_dst.s6_addr32[2] = 0;
871		ip6->ip6_dst.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
872		flags &= ~ND_NA_FLAG_SOLICITED;
873	} else
874		ip6->ip6_dst = *daddr6;
875
876	/*
877	 * Select a source whose scope is the same as that of the dest.
878	 */
879	ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
880	if (ia == NULL) {
881		m_freem(m);
882		return;
883	}
884	ip6->ip6_src = ia->ia_addr.sin6_addr;
885	nd_na = (struct nd_neighbor_advert *)(ip6 + 1);
886	nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
887	nd_na->nd_na_code = 0;
888	nd_na->nd_na_target = *taddr6;
889	in6_clearscope(&nd_na->nd_na_target); /* XXX */
890
891	/*
892	 * "tlladdr" indicates NS's condition for adding tlladdr or not.
893	 * see nd6_ns_input() for details.
894	 * Basically, if NS packet is sent to unicast/anycast addr,
895	 * target lladdr option SHOULD NOT be included.
896	 */
897	if (tlladdr) {
898		/*
899		 * sdl0 != NULL indicates proxy NA.  If we do proxy, use
900		 * lladdr in sdl0.  If we are not proxying (sending NA for
901		 * my address) use lladdr configured for the interface.
902		 */
903		if (sdl0 == NULL)
904			mac = nd6_ifptomac(ifp);
905		else if (sdl0->sa_family == AF_LINK) {
906			struct sockaddr_dl *sdl;
907			sdl = (struct sockaddr_dl *)sdl0;
908			if (sdl->sdl_alen == ifp->if_addrlen)
909				mac = LLADDR(sdl);
910		}
911	}
912	if (tlladdr && mac) {
913		int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
914		struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1);
915
916		/* roundup to 8 bytes alignment! */
917		optlen = (optlen + 7) & ~7;
918
919		m->m_pkthdr.len += optlen;
920		m->m_len += optlen;
921		icmp6len += optlen;
922		bzero((caddr_t)nd_opt, optlen);
923		nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
924		nd_opt->nd_opt_len = optlen >> 3;
925		bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
926	} else
927		flags &= ~ND_NA_FLAG_OVERRIDE;
928
929	ip6->ip6_plen = htons((u_short)icmp6len);
930	nd_na->nd_na_flags_reserved = flags;
931	nd_na->nd_na_cksum = 0;
932	nd_na->nd_na_cksum =
933	    in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len);
934
935#ifdef IPSEC
936	/* Don't lookup socket */
937	(void)ipsec_setsocket(m, NULL);
938#endif
939	ip6_output(m, NULL, NULL, 0, &im6o, &outif, NULL);
940	if (outif) {
941		icmp6_ifstat_inc(outif, ifs6_out_msg);
942		icmp6_ifstat_inc(outif, ifs6_out_neighboradvert);
943	}
944	icmp6stat.icp6s_outhist[ND_NEIGHBOR_ADVERT]++;
945}
946
947caddr_t
948nd6_ifptomac(ifp)
949	struct ifnet *ifp;
950{
951	switch (ifp->if_type) {
952	case IFT_ARCNET:
953	case IFT_ETHER:
954	case IFT_FDDI:
955	case IFT_IEEE1394:
956#ifdef IFT_L2VLAN
957	case IFT_L2VLAN:
958#endif
959#ifdef IFT_IEEE80211
960	case IFT_IEEE80211:
961#endif
962	case IFT_ISO88025:
963		return ((caddr_t)(ifp + 1));
964	default:
965		return NULL;
966	}
967}
968
969TAILQ_HEAD(dadq_head, dadq);
970struct dadq {
971	TAILQ_ENTRY(dadq) dad_list;
972	struct ifaddr *dad_ifa;
973	int dad_count;		/* max NS to send */
974	int dad_ns_tcount;	/* # of trials to send NS */
975	int dad_ns_ocount;	/* NS sent so far */
976	int dad_ns_icount;
977	int dad_na_icount;
978	struct callout dad_timer_ch;
979};
980
981static struct dadq_head dadq;
982static int dad_init = 0;
983
984static struct dadq *
985nd6_dad_find(ifa)
986	struct ifaddr *ifa;
987{
988	struct dadq *dp;
989
990	for (dp = dadq.tqh_first; dp; dp = dp->dad_list.tqe_next) {
991		if (dp->dad_ifa == ifa)
992			return dp;
993	}
994	return NULL;
995}
996
997static void
998nd6_dad_starttimer(dp, ticks)
999	struct dadq *dp;
1000	int ticks;
1001{
1002
1003	callout_reset(&dp->dad_timer_ch, ticks,
1004	    (void (*) __P((void *)))nd6_dad_timer, (void *)dp->dad_ifa);
1005}
1006
1007static void
1008nd6_dad_stoptimer(dp)
1009	struct dadq *dp;
1010{
1011
1012	callout_stop(&dp->dad_timer_ch);
1013}
1014
1015/*
1016 * Start Duplicated Address Detection (DAD) for specified interface address.
1017 */
1018void
1019nd6_dad_start(ifa, tick)
1020	struct ifaddr *ifa;
1021	int *tick;	/* minimum delay ticks for IFF_UP event */
1022{
1023	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1024	struct dadq *dp;
1025
1026	if (!dad_init) {
1027		TAILQ_INIT(&dadq);
1028		dad_init++;
1029	}
1030
1031	/*
1032	 * If we don't need DAD, don't do it.
1033	 * There are several cases:
1034	 * - DAD is disabled (ip6_dad_count == 0)
1035	 * - the interface address is anycast
1036	 */
1037	if (!(ia->ia6_flags & IN6_IFF_TENTATIVE)) {
1038		log(LOG_DEBUG,
1039			"nd6_dad_start: called with non-tentative address "
1040			"%s(%s)\n",
1041			ip6_sprintf(&ia->ia_addr.sin6_addr),
1042			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1043		return;
1044	}
1045	if (ia->ia6_flags & IN6_IFF_ANYCAST) {
1046		ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1047		return;
1048	}
1049	if (!ip6_dad_count) {
1050		ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1051		return;
1052	}
1053	if (!ifa->ifa_ifp)
1054		panic("nd6_dad_start: ifa->ifa_ifp == NULL");
1055	if (!(ifa->ifa_ifp->if_flags & IFF_UP)) {
1056		return;
1057	}
1058	if (nd6_dad_find(ifa) != NULL) {
1059		/* DAD already in progress */
1060		return;
1061	}
1062
1063	dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT);
1064	if (dp == NULL) {
1065		log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
1066			"%s(%s)\n",
1067			ip6_sprintf(&ia->ia_addr.sin6_addr),
1068			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1069		return;
1070	}
1071	bzero(dp, sizeof(*dp));
1072	callout_init(&dp->dad_timer_ch, 0);
1073	TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
1074
1075	nd6log((LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
1076	    ip6_sprintf(&ia->ia_addr.sin6_addr)));
1077
1078	/*
1079	 * Send NS packet for DAD, ip6_dad_count times.
1080	 * Note that we must delay the first transmission, if this is the
1081	 * first packet to be sent from the interface after interface
1082	 * (re)initialization.
1083	 */
1084	dp->dad_ifa = ifa;
1085	IFAREF(ifa);	/* just for safety */
1086	dp->dad_count = ip6_dad_count;
1087	dp->dad_ns_icount = dp->dad_na_icount = 0;
1088	dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
1089	if (tick == NULL) {
1090		nd6_dad_ns_output(dp, ifa);
1091		nd6_dad_starttimer(dp,
1092		    ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
1093	} else {
1094		int ntick;
1095
1096		if (*tick == 0)
1097			ntick = arc4random() % (MAX_RTR_SOLICITATION_DELAY * hz);
1098		else
1099			ntick = *tick + arc4random() % (hz / 2);
1100		*tick = ntick;
1101		nd6_dad_starttimer(dp, ntick);
1102	}
1103}
1104
1105/*
1106 * terminate DAD unconditionally.  used for address removals.
1107 */
1108void
1109nd6_dad_stop(ifa)
1110	struct ifaddr *ifa;
1111{
1112	struct dadq *dp;
1113
1114	if (!dad_init)
1115		return;
1116	dp = nd6_dad_find(ifa);
1117	if (!dp) {
1118		/* DAD wasn't started yet */
1119		return;
1120	}
1121
1122	nd6_dad_stoptimer(dp);
1123
1124	TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1125	free(dp, M_IP6NDP);
1126	dp = NULL;
1127	IFAFREE(ifa);
1128}
1129
1130static void
1131nd6_dad_timer(ifa)
1132	struct ifaddr *ifa;
1133{
1134	int s;
1135	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1136	struct dadq *dp;
1137
1138	s = splnet();		/* XXX */
1139
1140	/* Sanity check */
1141	if (ia == NULL) {
1142		log(LOG_ERR, "nd6_dad_timer: called with null parameter\n");
1143		goto done;
1144	}
1145	dp = nd6_dad_find(ifa);
1146	if (dp == NULL) {
1147		log(LOG_ERR, "nd6_dad_timer: DAD structure not found\n");
1148		goto done;
1149	}
1150	if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
1151		log(LOG_ERR, "nd6_dad_timer: called with duplicated address "
1152			"%s(%s)\n",
1153			ip6_sprintf(&ia->ia_addr.sin6_addr),
1154			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1155		goto done;
1156	}
1157	if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
1158		log(LOG_ERR, "nd6_dad_timer: called with non-tentative address "
1159			"%s(%s)\n",
1160			ip6_sprintf(&ia->ia_addr.sin6_addr),
1161			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1162		goto done;
1163	}
1164
1165	/* timeouted with IFF_{RUNNING,UP} check */
1166	if (dp->dad_ns_tcount > dad_maxtry) {
1167		nd6log((LOG_INFO, "%s: could not run DAD, driver problem?\n",
1168		    if_name(ifa->ifa_ifp)));
1169
1170		TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1171		free(dp, M_IP6NDP);
1172		dp = NULL;
1173		IFAFREE(ifa);
1174		goto done;
1175	}
1176
1177	/* Need more checks? */
1178	if (dp->dad_ns_ocount < dp->dad_count) {
1179		/*
1180		 * We have more NS to go.  Send NS packet for DAD.
1181		 */
1182		nd6_dad_ns_output(dp, ifa);
1183		nd6_dad_starttimer(dp,
1184		    ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
1185	} else {
1186		/*
1187		 * We have transmitted sufficient number of DAD packets.
1188		 * See what we've got.
1189		 */
1190		int duplicate;
1191
1192		duplicate = 0;
1193
1194		if (dp->dad_na_icount) {
1195			/*
1196			 * the check is in nd6_dad_na_input(),
1197			 * but just in case
1198			 */
1199			duplicate++;
1200		}
1201
1202		if (dp->dad_ns_icount) {
1203#if 0 /* heuristics */
1204			/*
1205			 * if
1206			 * - we have sent many(?) DAD NS, and
1207			 * - the number of NS we sent equals to the
1208			 *   number of NS we've got, and
1209			 * - we've got no NA
1210			 * we may have a faulty network card/driver which
1211			 * loops back multicasts to myself.
1212			 */
1213			if (3 < dp->dad_count
1214			 && dp->dad_ns_icount == dp->dad_count
1215			 && dp->dad_na_icount == 0) {
1216				log(LOG_INFO, "DAD questionable for %s(%s): "
1217				    "network card loops back multicast?\n",
1218				    ip6_sprintf(&ia->ia_addr.sin6_addr),
1219				    if_name(ifa->ifa_ifp));
1220				/* XXX consider it a duplicate or not? */
1221				/* duplicate++; */
1222			} else {
1223				/* We've seen NS, means DAD has failed. */
1224				duplicate++;
1225			}
1226#else
1227			/* We've seen NS, means DAD has failed. */
1228			duplicate++;
1229#endif
1230		}
1231
1232		if (duplicate) {
1233			/* (*dp) will be freed in nd6_dad_duplicated() */
1234			dp = NULL;
1235			nd6_dad_duplicated(ifa);
1236		} else {
1237			/*
1238			 * We are done with DAD.  No NA came, no NS came.
1239			 * duplicated address found.
1240			 */
1241			ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1242
1243			nd6log((LOG_DEBUG,
1244			    "%s: DAD complete for %s - no duplicates found\n",
1245			    if_name(ifa->ifa_ifp),
1246			    ip6_sprintf(&ia->ia_addr.sin6_addr)));
1247
1248			TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1249			free(dp, M_IP6NDP);
1250			dp = NULL;
1251			IFAFREE(ifa);
1252		}
1253	}
1254
1255done:
1256	splx(s);
1257}
1258
1259void
1260nd6_dad_duplicated(ifa)
1261	struct ifaddr *ifa;
1262{
1263	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1264	struct dadq *dp;
1265
1266	dp = nd6_dad_find(ifa);
1267	if (dp == NULL) {
1268		log(LOG_ERR, "nd6_dad_duplicated: DAD structure not found\n");
1269		return;
1270	}
1271
1272	log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: "
1273	    "NS in/out=%d/%d, NA in=%d\n",
1274	    if_name(ifa->ifa_ifp), ip6_sprintf(&ia->ia_addr.sin6_addr),
1275	    dp->dad_ns_icount, dp->dad_ns_ocount, dp->dad_na_icount);
1276
1277	ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1278	ia->ia6_flags |= IN6_IFF_DUPLICATED;
1279
1280	/* We are done with DAD, with duplicated address found. (failure) */
1281	nd6_dad_stoptimer(dp);
1282
1283	log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n",
1284	    if_name(ifa->ifa_ifp), ip6_sprintf(&ia->ia_addr.sin6_addr));
1285	log(LOG_ERR, "%s: manual intervention required\n",
1286	    if_name(ifa->ifa_ifp));
1287
1288	TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1289	free(dp, M_IP6NDP);
1290	dp = NULL;
1291	IFAFREE(ifa);
1292}
1293
1294static void
1295nd6_dad_ns_output(dp, ifa)
1296	struct dadq *dp;
1297	struct ifaddr *ifa;
1298{
1299	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1300	struct ifnet *ifp = ifa->ifa_ifp;
1301
1302	dp->dad_ns_tcount++;
1303	if ((ifp->if_flags & IFF_UP) == 0) {
1304#if 0
1305		printf("%s: interface down?\n", if_name(ifp));
1306#endif
1307		return;
1308	}
1309	if ((ifp->if_flags & IFF_RUNNING) == 0) {
1310#if 0
1311		printf("%s: interface not running?\n", if_name(ifp));
1312#endif
1313		return;
1314	}
1315
1316	dp->dad_ns_ocount++;
1317	nd6_ns_output(ifp, NULL, &ia->ia_addr.sin6_addr, NULL, 1);
1318}
1319
1320static void
1321nd6_dad_ns_input(ifa)
1322	struct ifaddr *ifa;
1323{
1324	struct in6_ifaddr *ia;
1325	struct ifnet *ifp;
1326	const struct in6_addr *taddr6;
1327	struct dadq *dp;
1328	int duplicate;
1329
1330	if (!ifa)
1331		panic("ifa == NULL in nd6_dad_ns_input");
1332
1333	ia = (struct in6_ifaddr *)ifa;
1334	ifp = ifa->ifa_ifp;
1335	taddr6 = &ia->ia_addr.sin6_addr;
1336	duplicate = 0;
1337	dp = nd6_dad_find(ifa);
1338
1339	/* Quickhack - completely ignore DAD NS packets */
1340	if (dad_ignore_ns) {
1341		nd6log((LOG_INFO,
1342		    "nd6_dad_ns_input: ignoring DAD NS packet for "
1343		    "address %s(%s)\n", ip6_sprintf(taddr6),
1344		    if_name(ifa->ifa_ifp)));
1345		return;
1346	}
1347
1348	/*
1349	 * if I'm yet to start DAD, someone else started using this address
1350	 * first.  I have a duplicate and you win.
1351	 */
1352	if (!dp || dp->dad_ns_ocount == 0)
1353		duplicate++;
1354
1355	/* XXX more checks for loopback situation - see nd6_dad_timer too */
1356
1357	if (duplicate) {
1358		dp = NULL;	/* will be freed in nd6_dad_duplicated() */
1359		nd6_dad_duplicated(ifa);
1360	} else {
1361		/*
1362		 * not sure if I got a duplicate.
1363		 * increment ns count and see what happens.
1364		 */
1365		if (dp)
1366			dp->dad_ns_icount++;
1367	}
1368}
1369
1370static void
1371nd6_dad_na_input(ifa)
1372	struct ifaddr *ifa;
1373{
1374	struct dadq *dp;
1375
1376	if (!ifa)
1377		panic("ifa == NULL in nd6_dad_na_input");
1378
1379	dp = nd6_dad_find(ifa);
1380	if (dp)
1381		dp->dad_na_icount++;
1382
1383	/* remove the address. */
1384	nd6_dad_duplicated(ifa);
1385}
1386