xref: /freebsd/sys/netinet6/mld6.c (revision 1669d8afc64812c8d2d1d147ae1fd42ff441e1b1)
1 /*-
2  * Copyright (C) 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	$KAME: mld6.c,v 1.27 2001/04/04 05:17:30 itojun Exp $
30  */
31 
32 /*-
33  * Copyright (c) 1988 Stephen Deering.
34  * Copyright (c) 1992, 1993
35  *	The Regents of the University of California.  All rights reserved.
36  *
37  * This code is derived from software contributed to Berkeley by
38  * Stephen Deering of Stanford University.
39  *
40  * Redistribution and use in source and binary forms, with or without
41  * modification, are permitted provided that the following conditions
42  * are met:
43  * 1. Redistributions of source code must retain the above copyright
44  *    notice, this list of conditions and the following disclaimer.
45  * 2. Redistributions in binary form must reproduce the above copyright
46  *    notice, this list of conditions and the following disclaimer in the
47  *    documentation and/or other materials provided with the distribution.
48  * 4. Neither the name of the University nor the names of its contributors
49  *    may be used to endorse or promote products derived from this software
50  *    without specific prior written permission.
51  *
52  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
53  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
56  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
62  * SUCH DAMAGE.
63  *
64  *	@(#)igmp.c	8.1 (Berkeley) 7/19/93
65  */
66 
67 #include <sys/cdefs.h>
68 __FBSDID("$FreeBSD$");
69 
70 #include "opt_inet.h"
71 #include "opt_inet6.h"
72 
73 #include <sys/param.h>
74 #include <sys/systm.h>
75 #include <sys/mbuf.h>
76 #include <sys/socket.h>
77 #include <sys/protosw.h>
78 #include <sys/syslog.h>
79 #include <sys/kernel.h>
80 #include <sys/callout.h>
81 #include <sys/malloc.h>
82 
83 #include <net/if.h>
84 
85 #include <netinet/in.h>
86 #include <netinet/in_var.h>
87 #include <netinet6/in6_var.h>
88 #include <netinet/ip6.h>
89 #include <netinet6/ip6_var.h>
90 #include <netinet6/scope6_var.h>
91 #include <netinet/icmp6.h>
92 #include <netinet6/mld6_var.h>
93 
94 /*
95  * Protocol constants
96  */
97 
98 /* denotes that the MLD max response delay field specifies time in milliseconds */
99 #define MLD_TIMER_SCALE	1000
100 /*
101  * time between repetitions of a node's initial report of interest in a
102  * multicast address(in seconds)
103  */
104 #define MLD_UNSOLICITED_REPORT_INTERVAL	10
105 
106 static struct ip6_pktopts ip6_opts;
107 
108 static void mld6_sendpkt(struct in6_multi *, int, const struct in6_addr *);
109 static void mld_starttimer(struct in6_multi *);
110 static void mld_stoptimer(struct in6_multi *);
111 static void mld_timeo(struct in6_multi *);
112 static u_long mld_timerresid(struct in6_multi *);
113 
114 void
115 mld6_init(void)
116 {
117 	static u_int8_t hbh_buf[8];
118 	struct ip6_hbh *hbh = (struct ip6_hbh *)hbh_buf;
119 	u_int16_t rtalert_code = htons((u_int16_t)IP6OPT_RTALERT_MLD);
120 
121 	/* ip6h_nxt will be fill in later */
122 	hbh->ip6h_len = 0;	/* (8 >> 3) - 1 */
123 
124 	/* XXX: grotty hard coding... */
125 	hbh_buf[2] = IP6OPT_PADN;	/* 2 byte padding */
126 	hbh_buf[3] = 0;
127 	hbh_buf[4] = IP6OPT_ROUTER_ALERT;
128 	hbh_buf[5] = IP6OPT_RTALERT_LEN - 2;
129 	bcopy((caddr_t)&rtalert_code, &hbh_buf[6], sizeof(u_int16_t));
130 
131 	ip6_initpktopts(&ip6_opts);
132 	ip6_opts.ip6po_hbh = hbh;
133 }
134 
135 static void
136 mld_starttimer(struct in6_multi *in6m)
137 {
138 	struct timeval now;
139 
140 	microtime(&now);
141 	in6m->in6m_timer_expire.tv_sec = now.tv_sec + in6m->in6m_timer / hz;
142 	in6m->in6m_timer_expire.tv_usec = now.tv_usec +
143 	    (in6m->in6m_timer % hz) * (1000000 / hz);
144 	if (in6m->in6m_timer_expire.tv_usec > 1000000) {
145 		in6m->in6m_timer_expire.tv_sec++;
146 		in6m->in6m_timer_expire.tv_usec -= 1000000;
147 	}
148 
149 	/* start or restart the timer */
150 	callout_reset(in6m->in6m_timer_ch, in6m->in6m_timer,
151 	    (void (*)(void *))mld_timeo, in6m);
152 }
153 
154 static void
155 mld_stoptimer(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(struct in6_multi *in6m)
166 {
167 	int s = splnet();
168 
169 	in6m->in6m_timer = IN6M_TIMER_UNDEF;
170 
171 	callout_stop(in6m->in6m_timer_ch);
172 
173 	switch (in6m->in6m_state) {
174 	case MLD_REPORTPENDING:
175 		mld6_start_listening(in6m);
176 		break;
177 	default:
178 		mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
179 		break;
180 	}
181 
182 	splx(s);
183 }
184 
185 static u_long
186 mld_timerresid(struct in6_multi *in6m)
187 {
188 	struct timeval now, diff;
189 
190 	microtime(&now);
191 
192 	if (now.tv_sec > in6m->in6m_timer_expire.tv_sec ||
193 	    (now.tv_sec == in6m->in6m_timer_expire.tv_sec &&
194 	    now.tv_usec > in6m->in6m_timer_expire.tv_usec)) {
195 		return (0);
196 	}
197 	diff = in6m->in6m_timer_expire;
198 	diff.tv_sec -= now.tv_sec;
199 	diff.tv_usec -= now.tv_usec;
200 	if (diff.tv_usec < 0) {
201 		diff.tv_sec--;
202 		diff.tv_usec += 1000000;
203 	}
204 
205 	/* return the remaining time in milliseconds */
206 	return (((u_long)(diff.tv_sec * 1000000 + diff.tv_usec)) / 1000);
207 }
208 
209 void
210 mld6_start_listening(struct in6_multi *in6m)
211 {
212 	struct in6_addr all_in6;
213 	int s = splnet();
214 
215 	/*
216 	 * RFC2710 page 10:
217 	 * The node never sends a Report or Done for the link-scope all-nodes
218 	 * address.
219 	 * MLD messages are never sent for multicast addresses whose scope is 0
220 	 * (reserved) or 1 (node-local).
221 	 */
222 	all_in6 = in6addr_linklocal_allnodes;
223 	if (in6_setscope(&all_in6, in6m->in6m_ifp, NULL)) {
224 		/* XXX: this should not happen! */
225 		in6m->in6m_timer = 0;
226 		in6m->in6m_state = MLD_OTHERLISTENER;
227 	}
228 	if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_in6) ||
229 	    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
230 	    IPV6_ADDR_SCOPE_LINKLOCAL) {
231 		in6m->in6m_timer = 0;
232 		in6m->in6m_state = MLD_OTHERLISTENER;
233 	} else {
234 		mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
235 		in6m->in6m_timer = arc4random() %
236 			MLD_UNSOLICITED_REPORT_INTERVAL * hz;
237 		in6m->in6m_state = MLD_IREPORTEDLAST;
238 
239 		mld_starttimer(in6m);
240 	}
241 	splx(s);
242 }
243 
244 void
245 mld6_stop_listening(struct in6_multi *in6m)
246 {
247 	struct in6_addr allnode, allrouter;
248 
249 	allnode = in6addr_linklocal_allnodes;
250 	if (in6_setscope(&allnode, in6m->in6m_ifp, NULL)) {
251 		/* XXX: this should not happen! */
252 		return;
253 	}
254 	allrouter = in6addr_linklocal_allrouters;
255 	if (in6_setscope(&allrouter, in6m->in6m_ifp, NULL)) {
256 		/* XXX impossible */
257 		return;
258 	}
259 	if (in6m->in6m_state == MLD_IREPORTEDLAST &&
260 	    !IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &allnode) &&
261 	    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) >
262 	    IPV6_ADDR_SCOPE_INTFACELOCAL) {
263 		mld6_sendpkt(in6m, MLD_LISTENER_DONE, &allrouter);
264 	}
265 }
266 
267 void
268 mld6_input(struct mbuf *m, int off)
269 {
270 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
271 	struct mld_hdr *mldh;
272 	struct ifnet *ifp = m->m_pkthdr.rcvif;
273 	struct in6_multi *in6m;
274 	struct in6_addr mld_addr, all_in6;
275 	struct in6_ifaddr *ia;
276 	struct ifmultiaddr *ifma;
277 	int timer;		/* timer value in the MLD query header */
278 
279 #ifndef PULLDOWN_TEST
280 	IP6_EXTHDR_CHECK(m, off, sizeof(*mldh),);
281 	mldh = (struct mld_hdr *)(mtod(m, caddr_t) + off);
282 #else
283 	IP6_EXTHDR_GET(mldh, struct mld_hdr *, m, off, sizeof(*mldh));
284 	if (mldh == NULL) {
285 		icmp6stat.icp6s_tooshort++;
286 		return;
287 	}
288 #endif
289 
290 	/* source address validation */
291 	ip6 = mtod(m, struct ip6_hdr *); /* in case mpullup */
292 	if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
293 		char ip6bufs[INET6_ADDRSTRLEN], ip6bufg[INET6_ADDRSTRLEN];
294 		log(LOG_ERR,
295 		    "mld6_input: src %s is not link-local (grp=%s)\n",
296 		    ip6_sprintf(ip6bufs, &ip6->ip6_src),
297 		    ip6_sprintf(ip6bufg, &mldh->mld_addr));
298 		/*
299 		 * spec (RFC2710) does not explicitly
300 		 * specify to discard the packet from a non link-local
301 		 * source address. But we believe it's expected to do so.
302 		 * XXX: do we have to allow :: as source?
303 		 */
304 		m_freem(m);
305 		return;
306 	}
307 
308 	/*
309 	 * make a copy for local work (in6_setscope() may modify the 1st arg)
310 	 */
311 	mld_addr = mldh->mld_addr;
312 	if (in6_setscope(&mld_addr, ifp, NULL)) {
313 		/* XXX: this should not happen! */
314 		m_free(m);
315 		return;
316 	}
317 
318 	/*
319 	 * In the MLD6 specification, there are 3 states and a flag.
320 	 *
321 	 * In Non-Listener state, we simply don't have a membership record.
322 	 * In Delaying Listener state, our timer is running (in6m->in6m_timer)
323 	 * In Idle Listener state, our timer is not running
324 	 * (in6m->in6m_timer==IN6M_TIMER_UNDEF)
325 	 *
326 	 * The flag is in6m->in6m_state, it is set to MLD_OTHERLISTENER if
327 	 * we have heard a report from another member, or MLD_IREPORTEDLAST
328 	 * if we sent the last report.
329 	 */
330 	switch(mldh->mld_type) {
331 	case MLD_LISTENER_QUERY:
332 		if (ifp->if_flags & IFF_LOOPBACK)
333 			break;
334 
335 		if (!IN6_IS_ADDR_UNSPECIFIED(&mld_addr) &&
336 		    !IN6_IS_ADDR_MULTICAST(&mld_addr))
337 			break;	/* print error or log stat? */
338 
339 		all_in6 = in6addr_linklocal_allnodes;
340 		if (in6_setscope(&all_in6, ifp, NULL)) {
341 			/* XXX: this should not happen! */
342 			break;
343 		}
344 
345 		/*
346 		 * - Start the timers in all of our membership records
347 		 *   that the query applies to for the interface on
348 		 *   which the query arrived excl. those that belong
349 		 *   to the "all-nodes" group (ff02::1).
350 		 * - Restart any timer that is already running but has
351 		 *   A value longer than the requested timeout.
352 		 * - Use the value specified in the query message as
353 		 *   the maximum timeout.
354 		 */
355 		timer = ntohs(mldh->mld_maxdelay);
356 
357 		IFP_TO_IA6(ifp, ia);
358 		if (ia == NULL)
359 			break;
360 
361 		/*
362 		 * XXX: System timer resolution is too low to handle Max
363 		 * Response Delay, so set 1 to the internal timer even if
364 		 * the calculated value equals to zero when Max Response
365 		 * Delay is positive.
366 		 */
367 		timer = ntohs(mldh->mld_maxdelay) * PR_FASTHZ / MLD_TIMER_SCALE;
368 		if (timer == 0 && mldh->mld_maxdelay)
369 			timer = 1;
370 
371 		IF_ADDR_LOCK(ifp);
372 		TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
373 			if (ifma->ifma_addr->sa_family != AF_INET6)
374 				continue;
375 			in6m = (struct in6_multi *)ifma->ifma_protospec;
376 
377 			if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_in6) ||
378 			    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
379 			    IPV6_ADDR_SCOPE_LINKLOCAL)
380 				continue;
381 
382 			if (IN6_IS_ADDR_UNSPECIFIED(&mld_addr) ||
383 			    IN6_ARE_ADDR_EQUAL(&mld_addr, &in6m->in6m_addr)) {
384 				if (timer == 0) {
385 					/* send a report immediately */
386 					mld_stoptimer(in6m);
387 					mld6_sendpkt(in6m, MLD_LISTENER_REPORT,
388 						NULL);
389 					in6m->in6m_timer = 0; /* reset timer */
390 					in6m->in6m_state = MLD_IREPORTEDLAST;
391 				}
392 				else if (in6m->in6m_timer == IN6M_TIMER_UNDEF ||
393 				    mld_timerresid(in6m) > (u_long)timer) {
394 					in6m->in6m_timer = arc4random() %
395 					    (int)((long)(timer * hz) / 1000);
396 					mld_starttimer(in6m);
397 				}
398 			}
399 		}
400 		IF_ADDR_UNLOCK(ifp);
401 		break;
402 
403 	case MLD_LISTENER_REPORT:
404 		/*
405 		 * For fast leave to work, we have to know that we are the
406 		 * last person to send a report for this group.  Reports
407 		 * can potentially get looped back if we are a multicast
408 		 * router, so discard reports sourced by me.
409 		 * Note that it is impossible to check IFF_LOOPBACK flag of
410 		 * ifp for this purpose, since ip6_mloopback pass the physical
411 		 * interface to looutput.
412 		 */
413 		if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
414 			break;
415 
416 		if (!IN6_IS_ADDR_MULTICAST(&mld_addr))
417 			break;
418 
419 		/*
420 		 * If we belong to the group being reported, stop
421 		 * our timer for that group.
422 		 */
423 		IN6_LOOKUP_MULTI(mld_addr, ifp, in6m);
424 		if (in6m) {
425 			in6m->in6m_timer = 0; /* transit to idle state */
426 			in6m->in6m_state = MLD_OTHERLISTENER; /* clear flag */
427 		}
428 		break;
429 	default:		/* this is impossible */
430 		log(LOG_ERR, "mld6_input: illegal type(%d)", mldh->mld_type);
431 		break;
432 	}
433 
434 	m_freem(m);
435 }
436 
437 static void
438 mld6_sendpkt(struct in6_multi *in6m, int type, const struct in6_addr *dst)
439 {
440 	struct mbuf *mh, *md;
441 	struct mld_hdr *mldh;
442 	struct ip6_hdr *ip6;
443 	struct ip6_moptions im6o;
444 	struct in6_ifaddr *ia;
445 	struct ifnet *ifp = in6m->in6m_ifp;
446 	struct ifnet *outif = NULL;
447 
448 	/*
449 	 * At first, find a link local address on the outgoing interface
450 	 * to use as the source address of the MLD packet.
451 	 */
452 	if ((ia = in6ifa_ifpforlinklocal(ifp, IN6_IFF_NOTREADY|IN6_IFF_ANYCAST))
453 	    == NULL)
454 		return;
455 
456 	/*
457 	 * Allocate mbufs to store ip6 header and MLD header.
458 	 * We allocate 2 mbufs and make chain in advance because
459 	 * it is more convenient when inserting the hop-by-hop option later.
460 	 */
461 	MGETHDR(mh, M_DONTWAIT, MT_HEADER);
462 	if (mh == NULL)
463 		return;
464 	MGET(md, M_DONTWAIT, MT_DATA);
465 	if (md == NULL) {
466 		m_free(mh);
467 		return;
468 	}
469 	mh->m_next = md;
470 
471 	mh->m_pkthdr.rcvif = NULL;
472 	mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld_hdr);
473 	mh->m_len = sizeof(struct ip6_hdr);
474 	MH_ALIGN(mh, sizeof(struct ip6_hdr));
475 
476 	/* fill in the ip6 header */
477 	ip6 = mtod(mh, struct ip6_hdr *);
478 	ip6->ip6_flow = 0;
479 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
480 	ip6->ip6_vfc |= IPV6_VERSION;
481 	/* ip6_plen will be set later */
482 	ip6->ip6_nxt = IPPROTO_ICMPV6;
483 	/* ip6_hlim will be set by im6o.im6o_multicast_hlim */
484 	ip6->ip6_src = ia->ia_addr.sin6_addr;
485 	ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;
486 
487 	/* fill in the MLD header */
488 	md->m_len = sizeof(struct mld_hdr);
489 	mldh = mtod(md, struct mld_hdr *);
490 	mldh->mld_type = type;
491 	mldh->mld_code = 0;
492 	mldh->mld_cksum = 0;
493 	/* XXX: we assume the function will not be called for query messages */
494 	mldh->mld_maxdelay = 0;
495 	mldh->mld_reserved = 0;
496 	mldh->mld_addr = in6m->in6m_addr;
497 	in6_clearscope(&mldh->mld_addr); /* XXX */
498 	mldh->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6, sizeof(struct ip6_hdr),
499 				    sizeof(struct mld_hdr));
500 
501 	/* construct multicast option */
502 	bzero(&im6o, sizeof(im6o));
503 	im6o.im6o_multicast_ifp = ifp;
504 	im6o.im6o_multicast_hlim = 1;
505 
506 	/*
507 	 * Request loopback of the report if we are acting as a multicast
508 	 * router, so that the process-level routing daemon can hear it.
509 	 */
510 	im6o.im6o_multicast_loop = (ip6_mrouter != NULL);
511 
512 	/* increment output statictics */
513 	icmp6stat.icp6s_outhist[type]++;
514 
515 	ip6_output(mh, &ip6_opts, NULL, 0, &im6o, &outif, NULL);
516 	if (outif) {
517 		icmp6_ifstat_inc(outif, ifs6_out_msg);
518 		switch (type) {
519 		case MLD_LISTENER_QUERY:
520 			icmp6_ifstat_inc(outif, ifs6_out_mldquery);
521 			break;
522 		case MLD_LISTENER_REPORT:
523 			icmp6_ifstat_inc(outif, ifs6_out_mldreport);
524 			break;
525 		case MLD_LISTENER_DONE:
526 			icmp6_ifstat_inc(outif, ifs6_out_mlddone);
527 			break;
528 		}
529 	}
530 }
531 
532 /*
533  * Add an address to the list of IP6 multicast addresses for a given interface.
534  * Add source addresses to the list also, if upstream router is MLDv2 capable
535  * and the number of source is not 0.
536  */
537 struct in6_multi *
538 in6_addmulti(struct in6_addr *maddr6, struct ifnet *ifp,
539     int *errorp, int delay)
540 {
541 	struct in6_multi *in6m;
542 
543 	*errorp = 0;
544 	in6m = NULL;
545 
546 	IFF_LOCKGIANT(ifp);
547 	/*IN6_MULTI_LOCK();*/
548 
549 	IN6_LOOKUP_MULTI(*maddr6, ifp, in6m);
550 	if (in6m != NULL) {
551 		/*
552 		 * If we already joined this group, just bump the
553 		 * refcount and return it.
554 		 */
555 		KASSERT(in6m->in6m_refcount >= 1,
556 		    ("%s: bad refcount %d", __func__, in6m->in6m_refcount));
557 		++in6m->in6m_refcount;
558 	} else do {
559 		struct in6_multi *nin6m;
560 		struct ifmultiaddr *ifma;
561 		struct sockaddr_in6 sa6;
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 
568 		*errorp = if_addmulti(ifp, (struct sockaddr *)&sa6, &ifma);
569 		if (*errorp)
570 			break;
571 
572 		/*
573 		 * If ifma->ifma_protospec is null, then if_addmulti() created
574 		 * a new record.  Otherwise, bump refcount, and we are done.
575 		 */
576 		if (ifma->ifma_protospec != NULL) {
577 			in6m = ifma->ifma_protospec;
578 			++in6m->in6m_refcount;
579 			break;
580 		}
581 
582 		nin6m = malloc(sizeof(*nin6m), M_IP6MADDR, M_NOWAIT | M_ZERO);
583 		if (nin6m == NULL) {
584 			if_delmulti_ifma(ifma);
585 			break;
586 		}
587 
588 		nin6m->in6m_addr = *maddr6;
589 		nin6m->in6m_ifp = ifp;
590 		nin6m->in6m_refcount = 1;
591 		nin6m->in6m_ifma = ifma;
592 		ifma->ifma_protospec = nin6m;
593 
594 		nin6m->in6m_timer_ch = malloc(sizeof(*nin6m->in6m_timer_ch),
595 		    M_IP6MADDR, M_NOWAIT);
596 		if (nin6m->in6m_timer_ch == NULL) {
597 			free(nin6m, M_IP6MADDR);
598 			if_delmulti_ifma(ifma);
599 			break;
600 		}
601 
602 		LIST_INSERT_HEAD(&in6_multihead, nin6m, in6m_entry);
603 
604 		callout_init(nin6m->in6m_timer_ch, 0);
605 		nin6m->in6m_timer = delay;
606 		if (nin6m->in6m_timer > 0) {
607 			nin6m->in6m_state = MLD_REPORTPENDING;
608 			mld_starttimer(nin6m);
609 		}
610 
611 		mld6_start_listening(nin6m);
612 
613 		in6m = nin6m;
614 
615 	} while (0);
616 
617 	/*IN6_MULTI_UNLOCK();*/
618 	IFF_UNLOCKGIANT(ifp);
619 
620 	return (in6m);
621 }
622 
623 /*
624  * Delete a multicast address record.
625  *
626  * TODO: Locking, as per netinet.
627  */
628 void
629 in6_delmulti(struct in6_multi *in6m)
630 {
631 	struct ifmultiaddr *ifma;
632 
633 	KASSERT(in6m->in6m_refcount >= 1, ("%s: freeing freed in6m", __func__));
634 
635 	if (--in6m->in6m_refcount == 0) {
636 		mld_stoptimer(in6m);
637 		mld6_stop_listening(in6m);
638 
639 		ifma = in6m->in6m_ifma;
640 		KASSERT(ifma->ifma_protospec == in6m,
641 		    ("%s: ifma_protospec != in6m", __func__));
642 		ifma->ifma_protospec = NULL;
643 
644 		LIST_REMOVE(in6m, in6m_entry);
645 		free(in6m->in6m_timer_ch, M_IP6MADDR);
646 		free(in6m, M_IP6MADDR);
647 
648 		if_delmulti_ifma(ifma);
649 	}
650 }
651