xref: /freebsd/sys/netinet6/mld6.c (revision acd3428b7d3e94cef0e1881c868cb4b131d4ff41)
1 /*	$FreeBSD$	*/
2 /*	$KAME: mld6.c,v 1.27 2001/04/04 05:17:30 itojun Exp $	*/
3 
4 /*-
5  * Copyright (C) 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 /*-
34  * Copyright (c) 1988 Stephen Deering.
35  * Copyright (c) 1992, 1993
36  *	The Regents of the University of California.  All rights reserved.
37  *
38  * This code is derived from software contributed to Berkeley by
39  * Stephen Deering of Stanford University.
40  *
41  * Redistribution and use in source and binary forms, with or without
42  * modification, are permitted provided that the following conditions
43  * are met:
44  * 1. Redistributions of source code must retain the above copyright
45  *    notice, this list of conditions and the following disclaimer.
46  * 2. Redistributions in binary form must reproduce the above copyright
47  *    notice, this list of conditions and the following disclaimer in the
48  *    documentation and/or other materials provided with the distribution.
49  * 4. Neither the name of the University nor the names of its contributors
50  *    may be used to endorse or promote products derived from this software
51  *    without specific prior written permission.
52  *
53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
63  * SUCH DAMAGE.
64  *
65  *	@(#)igmp.c	8.1 (Berkeley) 7/19/93
66  */
67 
68 #include "opt_inet.h"
69 #include "opt_inet6.h"
70 
71 #include <sys/param.h>
72 #include <sys/systm.h>
73 #include <sys/mbuf.h>
74 #include <sys/socket.h>
75 #include <sys/protosw.h>
76 #include <sys/syslog.h>
77 #include <sys/kernel.h>
78 #include <sys/callout.h>
79 #include <sys/malloc.h>
80 
81 #include <net/if.h>
82 
83 #include <netinet/in.h>
84 #include <netinet/in_var.h>
85 #include <netinet6/in6_var.h>
86 #include <netinet/ip6.h>
87 #include <netinet6/ip6_var.h>
88 #include <netinet6/scope6_var.h>
89 #include <netinet/icmp6.h>
90 #include <netinet6/mld6_var.h>
91 
92 /*
93  * Protocol constants
94  */
95 
96 /* denotes that the MLD max response delay field specifies time in milliseconds */
97 #define MLD_TIMER_SCALE	1000
98 /*
99  * time between repetitions of a node's initial report of interest in a
100  * multicast address(in seconds)
101  */
102 #define MLD_UNSOLICITED_REPORT_INTERVAL	10
103 
104 static struct ip6_pktopts ip6_opts;
105 
106 static void mld6_sendpkt(struct in6_multi *, int, const struct in6_addr *);
107 static void mld_starttimer(struct in6_multi *);
108 static void mld_stoptimer(struct in6_multi *);
109 static void mld_timeo(struct in6_multi *);
110 static u_long mld_timerresid(struct in6_multi *);
111 
112 void
113 mld6_init()
114 {
115 	static u_int8_t hbh_buf[8];
116 	struct ip6_hbh *hbh = (struct ip6_hbh *)hbh_buf;
117 	u_int16_t rtalert_code = htons((u_int16_t)IP6OPT_RTALERT_MLD);
118 
119 	/* ip6h_nxt will be fill in later */
120 	hbh->ip6h_len = 0;	/* (8 >> 3) - 1 */
121 
122 	/* XXX: grotty hard coding... */
123 	hbh_buf[2] = IP6OPT_PADN;	/* 2 byte padding */
124 	hbh_buf[3] = 0;
125 	hbh_buf[4] = IP6OPT_ROUTER_ALERT;
126 	hbh_buf[5] = IP6OPT_RTALERT_LEN - 2;
127 	bcopy((caddr_t)&rtalert_code, &hbh_buf[6], sizeof(u_int16_t));
128 
129 	ip6_initpktopts(&ip6_opts);
130 	ip6_opts.ip6po_hbh = hbh;
131 }
132 
133 static void
134 mld_starttimer(in6m)
135 	struct in6_multi *in6m;
136 {
137 	struct timeval now;
138 
139 	microtime(&now);
140 	in6m->in6m_timer_expire.tv_sec = now.tv_sec + in6m->in6m_timer / hz;
141 	in6m->in6m_timer_expire.tv_usec = now.tv_usec +
142 	    (in6m->in6m_timer % hz) * (1000000 / hz);
143 	if (in6m->in6m_timer_expire.tv_usec > 1000000) {
144 		in6m->in6m_timer_expire.tv_sec++;
145 		in6m->in6m_timer_expire.tv_usec -= 1000000;
146 	}
147 
148 	/* start or restart the timer */
149 	callout_reset(in6m->in6m_timer_ch, in6m->in6m_timer,
150 	    (void (*) __P((void *)))mld_timeo, in6m);
151 }
152 
153 static void
154 mld_stoptimer(in6m)
155 	struct in6_multi *in6m;
156 {
157 	if (in6m->in6m_timer == IN6M_TIMER_UNDEF)
158 		return;
159 
160 	callout_stop(in6m->in6m_timer_ch);
161 	in6m->in6m_timer = IN6M_TIMER_UNDEF;
162 }
163 
164 static void
165 mld_timeo(in6m)
166 	struct in6_multi *in6m;
167 {
168 	int s = splnet();
169 
170 	in6m->in6m_timer = IN6M_TIMER_UNDEF;
171 
172 	callout_stop(in6m->in6m_timer_ch);
173 
174 	switch (in6m->in6m_state) {
175 	case MLD_REPORTPENDING:
176 		mld6_start_listening(in6m);
177 		break;
178 	default:
179 		mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
180 		break;
181 	}
182 
183 	splx(s);
184 }
185 
186 static u_long
187 mld_timerresid(in6m)
188 	struct in6_multi *in6m;
189 {
190 	struct timeval now, diff;
191 
192 	microtime(&now);
193 
194 	if (now.tv_sec > in6m->in6m_timer_expire.tv_sec ||
195 	    (now.tv_sec == in6m->in6m_timer_expire.tv_sec &&
196 	    now.tv_usec > in6m->in6m_timer_expire.tv_usec)) {
197 		return (0);
198 	}
199 	diff = in6m->in6m_timer_expire;
200 	diff.tv_sec -= now.tv_sec;
201 	diff.tv_usec -= now.tv_usec;
202 	if (diff.tv_usec < 0) {
203 		diff.tv_sec--;
204 		diff.tv_usec += 1000000;
205 	}
206 
207 	/* return the remaining time in milliseconds */
208 	return (((u_long)(diff.tv_sec * 1000000 + diff.tv_usec)) / 1000);
209 }
210 
211 void
212 mld6_start_listening(in6m)
213 	struct in6_multi *in6m;
214 {
215 	struct in6_addr all_in6;
216 	int s = splnet();
217 
218 	/*
219 	 * RFC2710 page 10:
220 	 * The node never sends a Report or Done for the link-scope all-nodes
221 	 * address.
222 	 * MLD messages are never sent for multicast addresses whose scope is 0
223 	 * (reserved) or 1 (node-local).
224 	 */
225 	all_in6 = in6addr_linklocal_allnodes;
226 	if (in6_setscope(&all_in6, in6m->in6m_ifp, NULL)) {
227 		/* XXX: this should not happen! */
228 		in6m->in6m_timer = 0;
229 		in6m->in6m_state = MLD_OTHERLISTENER;
230 	}
231 	if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_in6) ||
232 	    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
233 	    IPV6_ADDR_SCOPE_LINKLOCAL) {
234 		in6m->in6m_timer = 0;
235 		in6m->in6m_state = MLD_OTHERLISTENER;
236 	} else {
237 		mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
238 		in6m->in6m_timer = arc4random() %
239 			MLD_UNSOLICITED_REPORT_INTERVAL * hz;
240 		in6m->in6m_state = MLD_IREPORTEDLAST;
241 
242 		mld_starttimer(in6m);
243 	}
244 	splx(s);
245 }
246 
247 void
248 mld6_stop_listening(in6m)
249 	struct in6_multi *in6m;
250 {
251 	struct in6_addr allnode, allrouter;
252 
253 	allnode = in6addr_linklocal_allnodes;
254 	if (in6_setscope(&allnode, in6m->in6m_ifp, NULL)) {
255 		/* XXX: this should not happen! */
256 		return;
257 	}
258 	allrouter = in6addr_linklocal_allrouters;
259 	if (in6_setscope(&allrouter, in6m->in6m_ifp, NULL)) {
260 		/* XXX impossible */
261 		return;
262 	}
263 	if (in6m->in6m_state == MLD_IREPORTEDLAST &&
264 	    !IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &allnode) &&
265 	    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) >
266 	    IPV6_ADDR_SCOPE_INTFACELOCAL) {
267 		mld6_sendpkt(in6m, MLD_LISTENER_DONE, &allrouter);
268 	}
269 }
270 
271 void
272 mld6_input(m, off)
273 	struct mbuf *m;
274 	int off;
275 {
276 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
277 	struct mld_hdr *mldh;
278 	struct ifnet *ifp = m->m_pkthdr.rcvif;
279 	struct in6_multi *in6m;
280 	struct in6_addr mld_addr, all_in6;
281 	struct in6_ifaddr *ia;
282 	struct ifmultiaddr *ifma;
283 	int timer;		/* timer value in the MLD query header */
284 
285 #ifndef PULLDOWN_TEST
286 	IP6_EXTHDR_CHECK(m, off, sizeof(*mldh),);
287 	mldh = (struct mld_hdr *)(mtod(m, caddr_t) + off);
288 #else
289 	IP6_EXTHDR_GET(mldh, struct mld_hdr *, m, off, sizeof(*mldh));
290 	if (mldh == NULL) {
291 		icmp6stat.icp6s_tooshort++;
292 		return;
293 	}
294 #endif
295 
296 	/* source address validation */
297 	ip6 = mtod(m, struct ip6_hdr *); /* in case mpullup */
298 	if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
299 		log(LOG_ERR,
300 		    "mld6_input: src %s is not link-local (grp=%s)\n",
301 		    ip6_sprintf(&ip6->ip6_src),
302 		    ip6_sprintf(&mldh->mld_addr));
303 		/*
304 		 * spec (RFC2710) does not explicitly
305 		 * specify to discard the packet from a non link-local
306 		 * source address. But we believe it's expected to do so.
307 		 * XXX: do we have to allow :: as source?
308 		 */
309 		m_freem(m);
310 		return;
311 	}
312 
313 	/*
314 	 * make a copy for local work (in6_setscope() may modify the 1st arg)
315 	 */
316 	mld_addr = mldh->mld_addr;
317 	if (in6_setscope(&mld_addr, ifp, NULL)) {
318 		/* XXX: this should not happen! */
319 		m_free(m);
320 		return;
321 	}
322 
323 	/*
324 	 * In the MLD6 specification, there are 3 states and a flag.
325 	 *
326 	 * In Non-Listener state, we simply don't have a membership record.
327 	 * In Delaying Listener state, our timer is running (in6m->in6m_timer)
328 	 * In Idle Listener state, our timer is not running
329 	 * (in6m->in6m_timer==IN6M_TIMER_UNDEF)
330 	 *
331 	 * The flag is in6m->in6m_state, it is set to MLD_OTHERLISTENER if
332 	 * we have heard a report from another member, or MLD_IREPORTEDLAST
333 	 * if we sent the last report.
334 	 */
335 	switch(mldh->mld_type) {
336 	case MLD_LISTENER_QUERY:
337 		if (ifp->if_flags & IFF_LOOPBACK)
338 			break;
339 
340 		if (!IN6_IS_ADDR_UNSPECIFIED(&mld_addr) &&
341 		    !IN6_IS_ADDR_MULTICAST(&mld_addr))
342 			break;	/* print error or log stat? */
343 
344 		all_in6 = in6addr_linklocal_allnodes;
345 		if (in6_setscope(&all_in6, ifp, NULL)) {
346 			/* XXX: this should not happen! */
347 			break;
348 		}
349 
350 		/*
351 		 * - Start the timers in all of our membership records
352 		 *   that the query applies to for the interface on
353 		 *   which the query arrived excl. those that belong
354 		 *   to the "all-nodes" group (ff02::1).
355 		 * - Restart any timer that is already running but has
356 		 *   A value longer than the requested timeout.
357 		 * - Use the value specified in the query message as
358 		 *   the maximum timeout.
359 		 */
360 		timer = ntohs(mldh->mld_maxdelay);
361 
362 		IFP_TO_IA6(ifp, ia);
363 		if (ia == NULL)
364 			break;
365 
366 		/*
367 		 * XXX: System timer resolution is too low to handle Max
368 		 * Response Delay, so set 1 to the internal timer even if
369 		 * the calculated value equals to zero when Max Response
370 		 * Delay is positive.
371 		 */
372 		timer = ntohs(mldh->mld_maxdelay) * PR_FASTHZ / MLD_TIMER_SCALE;
373 		if (timer == 0 && mldh->mld_maxdelay)
374 			timer = 1;
375 
376 		IF_ADDR_LOCK(ifp);
377 		TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
378 			if (ifma->ifma_addr->sa_family != AF_INET6)
379 				continue;
380 			in6m = (struct in6_multi *)ifma->ifma_protospec;
381 
382 			if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_in6) ||
383 			    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
384 			    IPV6_ADDR_SCOPE_LINKLOCAL)
385 				continue;
386 
387 			if (IN6_IS_ADDR_UNSPECIFIED(&mld_addr) ||
388 			    IN6_ARE_ADDR_EQUAL(&mld_addr, &in6m->in6m_addr)) {
389 				if (timer == 0) {
390 					/* send a report immediately */
391 					mld_stoptimer(in6m);
392 					mld6_sendpkt(in6m, MLD_LISTENER_REPORT,
393 						NULL);
394 					in6m->in6m_timer = 0; /* reset timer */
395 					in6m->in6m_state = MLD_IREPORTEDLAST;
396 				}
397 				else if (in6m->in6m_timer == IN6M_TIMER_UNDEF ||
398 				    mld_timerresid(in6m) > (u_long)timer) {
399 					in6m->in6m_timer = arc4random() %
400 					    (int)((long)(timer * hz) / 1000);
401 					mld_starttimer(in6m);
402 				}
403 			}
404 		}
405 		IF_ADDR_UNLOCK(ifp);
406 		break;
407 
408 	case MLD_LISTENER_REPORT:
409 		/*
410 		 * For fast leave to work, we have to know that we are the
411 		 * last person to send a report for this group.  Reports
412 		 * can potentially get looped back if we are a multicast
413 		 * router, so discard reports sourced by me.
414 		 * Note that it is impossible to check IFF_LOOPBACK flag of
415 		 * ifp for this purpose, since ip6_mloopback pass the physical
416 		 * interface to looutput.
417 		 */
418 		if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
419 			break;
420 
421 		if (!IN6_IS_ADDR_MULTICAST(&mld_addr))
422 			break;
423 
424 		/*
425 		 * If we belong to the group being reported, stop
426 		 * our timer for that group.
427 		 */
428 		IN6_LOOKUP_MULTI(mld_addr, ifp, in6m);
429 		if (in6m) {
430 			in6m->in6m_timer = 0; /* transit to idle state */
431 			in6m->in6m_state = MLD_OTHERLISTENER; /* clear flag */
432 		}
433 		break;
434 	default:		/* this is impossible */
435 		log(LOG_ERR, "mld6_input: illegal type(%d)", mldh->mld_type);
436 		break;
437 	}
438 
439 	m_freem(m);
440 }
441 
442 static void
443 mld6_sendpkt(in6m, type, dst)
444 	struct in6_multi *in6m;
445 	int type;
446 	const struct in6_addr *dst;
447 {
448 	struct mbuf *mh, *md;
449 	struct mld_hdr *mldh;
450 	struct ip6_hdr *ip6;
451 	struct ip6_moptions im6o;
452 	struct in6_ifaddr *ia;
453 	struct ifnet *ifp = in6m->in6m_ifp;
454 	struct ifnet *outif = NULL;
455 
456 	/*
457 	 * At first, find a link local address on the outgoing interface
458 	 * to use as the source address of the MLD packet.
459 	 */
460 	if ((ia = in6ifa_ifpforlinklocal(ifp, IN6_IFF_NOTREADY|IN6_IFF_ANYCAST))
461 	    == NULL)
462 		return;
463 
464 	/*
465 	 * Allocate mbufs to store ip6 header and MLD header.
466 	 * We allocate 2 mbufs and make chain in advance because
467 	 * it is more convenient when inserting the hop-by-hop option later.
468 	 */
469 	MGETHDR(mh, M_DONTWAIT, MT_HEADER);
470 	if (mh == NULL)
471 		return;
472 	MGET(md, M_DONTWAIT, MT_DATA);
473 	if (md == NULL) {
474 		m_free(mh);
475 		return;
476 	}
477 	mh->m_next = md;
478 
479 	mh->m_pkthdr.rcvif = NULL;
480 	mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld_hdr);
481 	mh->m_len = sizeof(struct ip6_hdr);
482 	MH_ALIGN(mh, sizeof(struct ip6_hdr));
483 
484 	/* fill in the ip6 header */
485 	ip6 = mtod(mh, struct ip6_hdr *);
486 	ip6->ip6_flow = 0;
487 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
488 	ip6->ip6_vfc |= IPV6_VERSION;
489 	/* ip6_plen will be set later */
490 	ip6->ip6_nxt = IPPROTO_ICMPV6;
491 	/* ip6_hlim will be set by im6o.im6o_multicast_hlim */
492 	ip6->ip6_src = ia->ia_addr.sin6_addr;
493 	ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;
494 
495 	/* fill in the MLD header */
496 	md->m_len = sizeof(struct mld_hdr);
497 	mldh = mtod(md, struct mld_hdr *);
498 	mldh->mld_type = type;
499 	mldh->mld_code = 0;
500 	mldh->mld_cksum = 0;
501 	/* XXX: we assume the function will not be called for query messages */
502 	mldh->mld_maxdelay = 0;
503 	mldh->mld_reserved = 0;
504 	mldh->mld_addr = in6m->in6m_addr;
505 	in6_clearscope(&mldh->mld_addr); /* XXX */
506 	mldh->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6, sizeof(struct ip6_hdr),
507 				    sizeof(struct mld_hdr));
508 
509 	/* construct multicast option */
510 	bzero(&im6o, sizeof(im6o));
511 	im6o.im6o_multicast_ifp = ifp;
512 	im6o.im6o_multicast_hlim = 1;
513 
514 	/*
515 	 * Request loopback of the report if we are acting as a multicast
516 	 * router, so that the process-level routing daemon can hear it.
517 	 */
518 	im6o.im6o_multicast_loop = (ip6_mrouter != NULL);
519 
520 	/* increment output statictics */
521 	icmp6stat.icp6s_outhist[type]++;
522 
523 	ip6_output(mh, &ip6_opts, NULL, 0, &im6o, &outif, NULL);
524 	if (outif) {
525 		icmp6_ifstat_inc(outif, ifs6_out_msg);
526 		switch (type) {
527 		case MLD_LISTENER_QUERY:
528 			icmp6_ifstat_inc(outif, ifs6_out_mldquery);
529 			break;
530 		case MLD_LISTENER_REPORT:
531 			icmp6_ifstat_inc(outif, ifs6_out_mldreport);
532 			break;
533 		case MLD_LISTENER_DONE:
534 			icmp6_ifstat_inc(outif, ifs6_out_mlddone);
535 			break;
536 		}
537 	}
538 }
539 
540 /*
541  * Add an address to the list of IP6 multicast addresses for a given interface.
542  * Add source addresses to the list also, if upstream router is MLDv2 capable
543  * and the number of source is not 0.
544  */
545 struct	in6_multi *
546 in6_addmulti(maddr6, ifp, errorp, delay)
547 	struct in6_addr *maddr6;
548 	struct ifnet *ifp;
549 	int *errorp, delay;
550 {
551 	struct in6_multi *in6m;
552 	struct ifmultiaddr *ifma;
553 	struct sockaddr_in6 sa6;
554 	int	s = splnet();
555 
556 	*errorp = 0;
557 
558 	/*
559 	 * Call generic routine to add membership or increment
560 	 * refcount.  It wants addresses in the form of a sockaddr,
561 	 * so we build one here (being careful to zero the unused bytes).
562 	 */
563 	bzero(&sa6, sizeof(sa6));
564 	sa6.sin6_family = AF_INET6;
565 	sa6.sin6_len = sizeof(struct sockaddr_in6);
566 	sa6.sin6_addr = *maddr6;
567 	*errorp = if_addmulti(ifp, (struct sockaddr *)&sa6, &ifma);
568 	if (*errorp) {
569 		splx(s);
570 		return 0;
571 	}
572 
573 	/*
574 	 * If ifma->ifma_protospec is null, then if_addmulti() created
575 	 * a new record.  Otherwise, we are done.
576 	 */
577 	if (ifma->ifma_protospec != NULL) {
578 		splx(s);
579 		return ifma->ifma_protospec;
580 	}
581 
582 	/* XXX - if_addmulti uses M_WAITOK.  Can this really be called
583 	   at interrupt time?  If so, need to fix if_addmulti. XXX */
584 	in6m = (struct in6_multi *)malloc(sizeof(*in6m), M_IP6MADDR, M_NOWAIT);
585 	if (in6m == NULL) {
586 		splx(s);
587 		return (NULL);
588 	}
589 
590 	bzero(in6m, sizeof *in6m);
591 	in6m->in6m_addr = *maddr6;
592 	in6m->in6m_ifp = ifp;
593 	in6m->in6m_refcount = 1;
594 	in6m->in6m_ifma = ifma;
595 	ifma->ifma_protospec = in6m;
596 	in6m->in6m_timer_ch = malloc(sizeof(*in6m->in6m_timer_ch), M_IP6MADDR,
597 	    M_NOWAIT);
598 	if (in6m->in6m_timer_ch == NULL) {
599 		free(in6m, M_IP6MADDR);
600 		splx(s);
601 		return (NULL);
602 	}
603 	LIST_INSERT_HEAD(&in6_multihead, in6m, in6m_entry);
604 
605 	callout_init(in6m->in6m_timer_ch, 0);
606 	in6m->in6m_timer = delay;
607 	if (in6m->in6m_timer > 0) {
608 		in6m->in6m_state = MLD_REPORTPENDING;
609 		mld_starttimer(in6m);
610 
611 		splx(s);
612 		return (in6m);
613 	}
614 
615 	/*
616 	 * Let MLD6 know that we have joined a new IPv6 multicast
617 	 * group.
618 	 */
619 	mld6_start_listening(in6m);
620 	splx(s);
621 	return (in6m);
622 }
623 
624 /*
625  * Delete a multicast address record.
626  */
627 void
628 in6_delmulti(in6m)
629 	struct in6_multi *in6m;
630 {
631 	struct ifmultiaddr *ifma = in6m->in6m_ifma;
632 	int	s = splnet();
633 
634 	if (ifma->ifma_refcount == 1) {
635 		/*
636 		 * No remaining claims to this record; let MLD6 know
637 		 * that we are leaving the multicast group.
638 		 */
639 		mld_stoptimer(in6m);
640 		mld6_stop_listening(in6m);
641 		ifma->ifma_protospec = NULL;
642 		LIST_REMOVE(in6m, in6m_entry);
643 		free(in6m->in6m_timer_ch, M_IP6MADDR);
644 		free(in6m, M_IP6MADDR);
645 	}
646 	/* XXX - should be separate API for when we have an ifma? */
647 	if_delmulti(ifma->ifma_ifp, ifma->ifma_addr);
648 	splx(s);
649 }
650