xref: /freebsd/sys/netinet6/mld6.c (revision 3642298923e528d795e3a30ec165d2b469e28b40)
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/malloc.h>
78 
79 #include <net/if.h>
80 
81 #include <netinet/in.h>
82 #include <netinet/in_var.h>
83 #include <netinet/ip6.h>
84 #include <netinet6/ip6_var.h>
85 #include <netinet6/scope6_var.h>
86 #include <netinet/icmp6.h>
87 #include <netinet6/mld6_var.h>
88 
89 #include <net/net_osdep.h>
90 
91 /*
92  * Protocol constants
93  */
94 
95 /* denotes that the MLD max response delay field specifies time in milliseconds */
96 #define MLD_TIMER_SCALE	1000
97 /*
98  * time between repetitions of a node's initial report of interest in a
99  * multicast address(in seconds)
100  */
101 #define MLD_UNSOLICITED_REPORT_INTERVAL	10
102 
103 static struct ip6_pktopts ip6_opts;
104 static int mld6_timers_are_running;
105 
106 static void mld6_sendpkt(struct in6_multi *, int, const struct in6_addr *);
107 
108 void
109 mld6_init()
110 {
111 	static u_int8_t hbh_buf[8];
112 	struct ip6_hbh *hbh = (struct ip6_hbh *)hbh_buf;
113 	u_int16_t rtalert_code = htons((u_int16_t)IP6OPT_RTALERT_MLD);
114 
115 	mld6_timers_are_running = 0;
116 
117 	/* ip6h_nxt will be fill in later */
118 	hbh->ip6h_len = 0;	/* (8 >> 3) - 1 */
119 
120 	/* XXX: grotty hard coding... */
121 	hbh_buf[2] = IP6OPT_PADN;	/* 2 byte padding */
122 	hbh_buf[3] = 0;
123 	hbh_buf[4] = IP6OPT_ROUTER_ALERT;
124 	hbh_buf[5] = IP6OPT_RTALERT_LEN - 2;
125 	bcopy((caddr_t)&rtalert_code, &hbh_buf[6], sizeof(u_int16_t));
126 
127 	ip6_initpktopts(&ip6_opts);
128 	ip6_opts.ip6po_hbh = hbh;
129 }
130 
131 void
132 mld6_start_listening(in6m)
133 	struct in6_multi *in6m;
134 {
135 	struct in6_addr all_in6;
136 	int s = splnet();
137 
138 	/*
139 	 * RFC2710 page 10:
140 	 * The node never sends a Report or Done for the link-scope all-nodes
141 	 * address.
142 	 * MLD messages are never sent for multicast addresses whose scope is 0
143 	 * (reserved) or 1 (node-local).
144 	 */
145 	all_in6 = in6addr_linklocal_allnodes;
146 	if (in6_setscope(&all_in6, in6m->in6m_ifp, NULL)) {
147 		/* XXX: this should not happen! */
148 		in6m->in6m_timer = 0;
149 		in6m->in6m_state = MLD_OTHERLISTENER;
150 	}
151 	if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_in6) ||
152 	    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
153 	    IPV6_ADDR_SCOPE_LINKLOCAL) {
154 		in6m->in6m_timer = 0;
155 		in6m->in6m_state = MLD_OTHERLISTENER;
156 	} else {
157 		mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
158 		in6m->in6m_timer =
159 			MLD_RANDOM_DELAY(MLD_UNSOLICITED_REPORT_INTERVAL *
160 					 PR_FASTHZ);
161 		in6m->in6m_state = MLD_IREPORTEDLAST;
162 		mld6_timers_are_running = 1;
163 	}
164 	splx(s);
165 }
166 
167 void
168 mld6_stop_listening(in6m)
169 	struct in6_multi *in6m;
170 {
171 	struct in6_addr allnode, allrouter;
172 
173 	allnode = in6addr_linklocal_allnodes;
174 	if (in6_setscope(&allnode, in6m->in6m_ifp, NULL)) {
175 		/* XXX: this should not happen! */
176 		return;
177 	}
178 	allrouter = in6addr_linklocal_allrouters;
179 	if (in6_setscope(&allrouter, in6m->in6m_ifp, NULL)) {
180 		/* XXX impossible */
181 		return;
182 	}
183 	if (in6m->in6m_state == MLD_IREPORTEDLAST &&
184 	    !IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &allnode) &&
185 	    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) >
186 	    IPV6_ADDR_SCOPE_INTFACELOCAL) {
187 		mld6_sendpkt(in6m, MLD_LISTENER_DONE, &allrouter);
188 	}
189 }
190 
191 void
192 mld6_input(m, off)
193 	struct mbuf *m;
194 	int off;
195 {
196 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
197 	struct mld_hdr *mldh;
198 	struct ifnet *ifp = m->m_pkthdr.rcvif;
199 	struct in6_multi *in6m;
200 	struct in6_addr mld_addr, all_in6;
201 	struct in6_ifaddr *ia;
202 	struct ifmultiaddr *ifma;
203 	int timer;		/* timer value in the MLD query header */
204 
205 #ifndef PULLDOWN_TEST
206 	IP6_EXTHDR_CHECK(m, off, sizeof(*mldh),);
207 	mldh = (struct mld_hdr *)(mtod(m, caddr_t) + off);
208 #else
209 	IP6_EXTHDR_GET(mldh, struct mld_hdr *, m, off, sizeof(*mldh));
210 	if (mldh == NULL) {
211 		icmp6stat.icp6s_tooshort++;
212 		return;
213 	}
214 #endif
215 
216 	/* source address validation */
217 	ip6 = mtod(m, struct ip6_hdr *); /* in case mpullup */
218 	if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
219 		log(LOG_ERR,
220 		    "mld6_input: src %s is not link-local (grp=%s)\n",
221 		    ip6_sprintf(&ip6->ip6_src),
222 		    ip6_sprintf(&mldh->mld_addr));
223 		/*
224 		 * spec (RFC2710) does not explicitly
225 		 * specify to discard the packet from a non link-local
226 		 * source address. But we believe it's expected to do so.
227 		 * XXX: do we have to allow :: as source?
228 		 */
229 		m_freem(m);
230 		return;
231 	}
232 
233 	/*
234 	 * make a copy for local work (in6_setscope() may modify the 1st arg)
235 	 */
236 	mld_addr = mldh->mld_addr;
237 	if (in6_setscope(&mld_addr, ifp, NULL)) {
238 		/* XXX: this should not happen! */
239 		m_free(m);
240 		return;
241 	}
242 
243 	/*
244 	 * In the MLD6 specification, there are 3 states and a flag.
245 	 *
246 	 * In Non-Listener state, we simply don't have a membership record.
247 	 * In Delaying Listener state, our timer is running (in6m->in6m_timer)
248 	 * In Idle Listener state, our timer is not running (in6m->in6m_timer==0)
249 	 *
250 	 * The flag is in6m->in6m_state, it is set to MLD_OTHERLISTENER if
251 	 * we have heard a report from another member, or MLD_IREPORTEDLAST
252 	 * if we sent the last report.
253 	 */
254 	switch(mldh->mld_type) {
255 	case MLD_LISTENER_QUERY:
256 		if (ifp->if_flags & IFF_LOOPBACK)
257 			break;
258 
259 		if (!IN6_IS_ADDR_UNSPECIFIED(&mld_addr) &&
260 		    !IN6_IS_ADDR_MULTICAST(&mld_addr))
261 			break;	/* print error or log stat? */
262 
263 		all_in6 = in6addr_linklocal_allnodes;
264 		if (in6_setscope(&all_in6, ifp, NULL)) {
265 			/* XXX: this should not happen! */
266 			break;
267 		}
268 
269 		/*
270 		 * - Start the timers in all of our membership records
271 		 *   that the query applies to for the interface on
272 		 *   which the query arrived excl. those that belong
273 		 *   to the "all-nodes" group (ff02::1).
274 		 * - Restart any timer that is already running but has
275 		 *   A value longer than the requested timeout.
276 		 * - Use the value specified in the query message as
277 		 *   the maximum timeout.
278 		 */
279 		IFP_TO_IA6(ifp, ia);
280 		if (ia == NULL)
281 			break;
282 
283 		/*
284 		 * XXX: System timer resolution is too low to handle Max
285 		 * Response Delay, so set 1 to the internal timer even if
286 		 * the calculated value equals to zero when Max Response
287 		 * Delay is positive.
288 		 */
289 		timer = ntohs(mldh->mld_maxdelay) * PR_FASTHZ / MLD_TIMER_SCALE;
290 		if (timer == 0 && mldh->mld_maxdelay)
291 			timer = 1;
292 
293 		IF_ADDR_LOCK(ifp);
294 		TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
295 			if (ifma->ifma_addr->sa_family != AF_INET6)
296 				continue;
297 			in6m = (struct in6_multi *)ifma->ifma_protospec;
298 
299 			if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_in6) ||
300 			    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
301 			    IPV6_ADDR_SCOPE_LINKLOCAL)
302 				continue;
303 
304 			if (IN6_IS_ADDR_UNSPECIFIED(&mld_addr) ||
305 			    IN6_ARE_ADDR_EQUAL(&mld_addr, &in6m->in6m_addr)) {
306 				if (timer == 0) {
307 					/* send a report immediately */
308 					mld6_sendpkt(in6m, MLD_LISTENER_REPORT,
309 						NULL);
310 					in6m->in6m_timer = 0; /* reset timer */
311 					in6m->in6m_state = MLD_IREPORTEDLAST;
312 				}
313 				else if (in6m->in6m_timer == 0 || /*idle state*/
314 					in6m->in6m_timer > timer) {
315 					in6m->in6m_timer =
316 						MLD_RANDOM_DELAY(timer);
317 					mld6_timers_are_running = 1;
318 				}
319 			}
320 		}
321 		IF_ADDR_UNLOCK(ifp);
322 		break;
323 
324 	case MLD_LISTENER_REPORT:
325 		/*
326 		 * For fast leave to work, we have to know that we are the
327 		 * last person to send a report for this group.  Reports
328 		 * can potentially get looped back if we are a multicast
329 		 * router, so discard reports sourced by me.
330 		 * Note that it is impossible to check IFF_LOOPBACK flag of
331 		 * ifp for this purpose, since ip6_mloopback pass the physical
332 		 * interface to looutput.
333 		 */
334 		if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
335 			break;
336 
337 		if (!IN6_IS_ADDR_MULTICAST(&mld_addr))
338 			break;
339 
340 		/*
341 		 * If we belong to the group being reported, stop
342 		 * our timer for that group.
343 		 */
344 		IN6_LOOKUP_MULTI(mld_addr, ifp, in6m);
345 		if (in6m) {
346 			in6m->in6m_timer = 0; /* transit to idle state */
347 			in6m->in6m_state = MLD_OTHERLISTENER; /* clear flag */
348 		}
349 		break;
350 	default:		/* this is impossible */
351 		log(LOG_ERR, "mld6_input: illegal type(%d)", mldh->mld_type);
352 		break;
353 	}
354 
355 	m_freem(m);
356 }
357 
358 void
359 mld6_fasttimeo()
360 {
361 	struct in6_multi *in6m;
362 	struct in6_multistep step;
363 	int s;
364 
365 	/*
366 	 * Quick check to see if any work needs to be done, in order
367 	 * to minimize the overhead of fasttimo processing.
368 	 */
369 	if (!mld6_timers_are_running)
370 		return;
371 
372 	s = splnet();
373 
374 	mld6_timers_are_running = 0;
375 	IN6_FIRST_MULTI(step, in6m);
376 	while (in6m != NULL) {
377 		if (in6m->in6m_timer == 0) {
378 			/* do nothing */
379 		} else if (--in6m->in6m_timer == 0) {
380 			mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
381 			in6m->in6m_state = MLD_IREPORTEDLAST;
382 		} else {
383 			mld6_timers_are_running = 1;
384 		}
385 		IN6_NEXT_MULTI(step, in6m);
386 	}
387 
388 	splx(s);
389 }
390 
391 static void
392 mld6_sendpkt(in6m, type, dst)
393 	struct in6_multi *in6m;
394 	int type;
395 	const struct in6_addr *dst;
396 {
397 	struct mbuf *mh, *md;
398 	struct mld_hdr *mldh;
399 	struct ip6_hdr *ip6;
400 	struct ip6_moptions im6o;
401 	struct in6_ifaddr *ia;
402 	struct ifnet *ifp = in6m->in6m_ifp;
403 	struct ifnet *outif = NULL;
404 
405 	/*
406 	 * At first, find a link local address on the outgoing interface
407 	 * to use as the source address of the MLD packet.
408 	 */
409 	if ((ia = in6ifa_ifpforlinklocal(ifp, IN6_IFF_NOTREADY|IN6_IFF_ANYCAST))
410 	    == NULL)
411 		return;
412 
413 	/*
414 	 * Allocate mbufs to store ip6 header and MLD header.
415 	 * We allocate 2 mbufs and make chain in advance because
416 	 * it is more convenient when inserting the hop-by-hop option later.
417 	 */
418 	MGETHDR(mh, M_DONTWAIT, MT_HEADER);
419 	if (mh == NULL)
420 		return;
421 	MGET(md, M_DONTWAIT, MT_DATA);
422 	if (md == NULL) {
423 		m_free(mh);
424 		return;
425 	}
426 	mh->m_next = md;
427 
428 	mh->m_pkthdr.rcvif = NULL;
429 	mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld_hdr);
430 	mh->m_len = sizeof(struct ip6_hdr);
431 	MH_ALIGN(mh, sizeof(struct ip6_hdr));
432 
433 	/* fill in the ip6 header */
434 	ip6 = mtod(mh, struct ip6_hdr *);
435 	ip6->ip6_flow = 0;
436 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
437 	ip6->ip6_vfc |= IPV6_VERSION;
438 	/* ip6_plen will be set later */
439 	ip6->ip6_nxt = IPPROTO_ICMPV6;
440 	/* ip6_hlim will be set by im6o.im6o_multicast_hlim */
441 	ip6->ip6_src = ia->ia_addr.sin6_addr;
442 	ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;
443 
444 	/* fill in the MLD header */
445 	md->m_len = sizeof(struct mld_hdr);
446 	mldh = mtod(md, struct mld_hdr *);
447 	mldh->mld_type = type;
448 	mldh->mld_code = 0;
449 	mldh->mld_cksum = 0;
450 	/* XXX: we assume the function will not be called for query messages */
451 	mldh->mld_maxdelay = 0;
452 	mldh->mld_reserved = 0;
453 	mldh->mld_addr = in6m->in6m_addr;
454 	in6_clearscope(&mldh->mld_addr); /* XXX */
455 	mldh->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6, sizeof(struct ip6_hdr),
456 				    sizeof(struct mld_hdr));
457 
458 	/* construct multicast option */
459 	bzero(&im6o, sizeof(im6o));
460 	im6o.im6o_multicast_ifp = ifp;
461 	im6o.im6o_multicast_hlim = 1;
462 
463 	/*
464 	 * Request loopback of the report if we are acting as a multicast
465 	 * router, so that the process-level routing daemon can hear it.
466 	 */
467 	im6o.im6o_multicast_loop = (ip6_mrouter != NULL);
468 
469 	/* increment output statictics */
470 	icmp6stat.icp6s_outhist[type]++;
471 
472 	ip6_output(mh, &ip6_opts, NULL, 0, &im6o, &outif, NULL);
473 	if (outif) {
474 		icmp6_ifstat_inc(outif, ifs6_out_msg);
475 		switch (type) {
476 		case MLD_LISTENER_QUERY:
477 			icmp6_ifstat_inc(outif, ifs6_out_mldquery);
478 			break;
479 		case MLD_LISTENER_REPORT:
480 			icmp6_ifstat_inc(outif, ifs6_out_mldreport);
481 			break;
482 		case MLD_LISTENER_DONE:
483 			icmp6_ifstat_inc(outif, ifs6_out_mlddone);
484 			break;
485 		}
486 	}
487 }
488 
489 /*
490  * Add an address to the list of IP6 multicast addresses for a given interface.
491  * Add source addresses to the list also, if upstream router is MLDv2 capable
492  * and the number of source is not 0.
493  */
494 struct	in6_multi *
495 in6_addmulti(maddr6, ifp, errorp)
496 	struct in6_addr *maddr6;
497 	struct ifnet *ifp;
498 	int *errorp;
499 {
500 	struct in6_multi *in6m;
501 	struct ifmultiaddr *ifma;
502 	struct sockaddr_in6 sa6;
503 	int	s = splnet();
504 
505 	*errorp = 0;
506 
507 	/*
508 	 * Call generic routine to add membership or increment
509 	 * refcount.  It wants addresses in the form of a sockaddr,
510 	 * so we build one here (being careful to zero the unused bytes).
511 	 */
512 	bzero(&sa6, sizeof(sa6));
513 	sa6.sin6_family = AF_INET6;
514 	sa6.sin6_len = sizeof(struct sockaddr_in6);
515 	sa6.sin6_addr = *maddr6;
516 	*errorp = if_addmulti(ifp, (struct sockaddr *)&sa6, &ifma);
517 	if (*errorp) {
518 		splx(s);
519 		return 0;
520 	}
521 
522 	/*
523 	 * If ifma->ifma_protospec is null, then if_addmulti() created
524 	 * a new record.  Otherwise, we are done.
525 	 */
526 	if (ifma->ifma_protospec != NULL) {
527 		splx(s);
528 		return ifma->ifma_protospec;
529 	}
530 
531 	/* XXX - if_addmulti uses M_WAITOK.  Can this really be called
532 	   at interrupt time?  If so, need to fix if_addmulti. XXX */
533 	in6m = (struct in6_multi *)malloc(sizeof(*in6m), M_IP6MADDR, M_NOWAIT);
534 	if (in6m == NULL) {
535 		splx(s);
536 		return (NULL);
537 	}
538 
539 	bzero(in6m, sizeof *in6m);
540 	in6m->in6m_addr = *maddr6;
541 	in6m->in6m_ifp = ifp;
542 	in6m->in6m_refcount = 1;
543 	in6m->in6m_ifma = ifma;
544 	ifma->ifma_protospec = in6m;
545 	LIST_INSERT_HEAD(&in6_multihead, in6m, in6m_entry);
546 
547 	/*
548 	 * Let MLD6 know that we have joined a new IPv6 multicast
549 	 * group.
550 	 */
551 	mld6_start_listening(in6m);
552 	splx(s);
553 	return (in6m);
554 }
555 
556 /*
557  * Delete a multicast address record.
558  */
559 void
560 in6_delmulti(in6m)
561 	struct in6_multi *in6m;
562 {
563 	struct ifmultiaddr *ifma = in6m->in6m_ifma;
564 	int	s = splnet();
565 
566 	if (ifma->ifma_refcount == 1) {
567 		/*
568 		 * No remaining claims to this record; let MLD6 know
569 		 * that we are leaving the multicast group.
570 		 */
571 		mld6_stop_listening(in6m);
572 		ifma->ifma_protospec = NULL;
573 		LIST_REMOVE(in6m, in6m_entry);
574 		free(in6m, M_IP6MADDR);
575 	}
576 	/* XXX - should be separate API for when we have an ifma? */
577 	if_delmulti(ifma->ifma_ifp, ifma->ifma_addr);
578 	splx(s);
579 }
580