xref: /freebsd/sys/netinet6/mld6.c (revision 148a8da8)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 2009 Bruce Simpson.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. The name of the author may not be used to endorse or promote
15  *    products derived from this software without specific prior written
16  *    permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  *	$KAME: mld6.c,v 1.27 2001/04/04 05:17:30 itojun Exp $
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  * 3. 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 <sys/cdefs.h>
69 __FBSDID("$FreeBSD$");
70 
71 #include "opt_inet.h"
72 #include "opt_inet6.h"
73 
74 #include <sys/param.h>
75 #include <sys/systm.h>
76 #include <sys/mbuf.h>
77 #include <sys/socket.h>
78 #include <sys/protosw.h>
79 #include <sys/sysctl.h>
80 #include <sys/kernel.h>
81 #include <sys/callout.h>
82 #include <sys/malloc.h>
83 #include <sys/module.h>
84 #include <sys/ktr.h>
85 
86 #include <net/if.h>
87 #include <net/if_var.h>
88 #include <net/route.h>
89 #include <net/vnet.h>
90 
91 #include <netinet/in.h>
92 #include <netinet/in_var.h>
93 #include <netinet6/in6_var.h>
94 #include <netinet/ip6.h>
95 #include <netinet6/ip6_var.h>
96 #include <netinet6/scope6_var.h>
97 #include <netinet/icmp6.h>
98 #include <netinet6/mld6.h>
99 #include <netinet6/mld6_var.h>
100 
101 #include <security/mac/mac_framework.h>
102 
103 #ifndef KTR_MLD
104 #define KTR_MLD KTR_INET6
105 #endif
106 
107 static struct mld_ifsoftc *
108 		mli_alloc_locked(struct ifnet *);
109 static void	mli_delete_locked(const struct ifnet *);
110 static void	mld_dispatch_packet(struct mbuf *);
111 static void	mld_dispatch_queue(struct mbufq *, int);
112 static void	mld_final_leave(struct in6_multi *, struct mld_ifsoftc *);
113 static void	mld_fasttimo_vnet(struct in6_multi_head *inmh);
114 static int	mld_handle_state_change(struct in6_multi *,
115 		    struct mld_ifsoftc *);
116 static int	mld_initial_join(struct in6_multi *, struct mld_ifsoftc *,
117 		    const int);
118 #ifdef KTR
119 static char *	mld_rec_type_to_str(const int);
120 #endif
121 static void	mld_set_version(struct mld_ifsoftc *, const int);
122 static void	mld_slowtimo_vnet(void);
123 static int	mld_v1_input_query(struct ifnet *, const struct ip6_hdr *,
124 		    /*const*/ struct mld_hdr *);
125 static int	mld_v1_input_report(struct ifnet *, const struct ip6_hdr *,
126 		    /*const*/ struct mld_hdr *);
127 static void	mld_v1_process_group_timer(struct in6_multi_head *,
128 		    struct in6_multi *);
129 static void	mld_v1_process_querier_timers(struct mld_ifsoftc *);
130 static int	mld_v1_transmit_report(struct in6_multi *, const int);
131 static void	mld_v1_update_group(struct in6_multi *, const int);
132 static void	mld_v2_cancel_link_timers(struct mld_ifsoftc *);
133 static void	mld_v2_dispatch_general_query(struct mld_ifsoftc *);
134 static struct mbuf *
135 		mld_v2_encap_report(struct ifnet *, struct mbuf *);
136 static int	mld_v2_enqueue_filter_change(struct mbufq *,
137 		    struct in6_multi *);
138 static int	mld_v2_enqueue_group_record(struct mbufq *,
139 		    struct in6_multi *, const int, const int, const int,
140 		    const int);
141 static int	mld_v2_input_query(struct ifnet *, const struct ip6_hdr *,
142 		    struct mbuf *, const int, const int);
143 static int	mld_v2_merge_state_changes(struct in6_multi *,
144 		    struct mbufq *);
145 static void	mld_v2_process_group_timers(struct in6_multi_head *,
146 		    struct mbufq *, struct mbufq *,
147 		    struct in6_multi *, const int);
148 static int	mld_v2_process_group_query(struct in6_multi *,
149 		    struct mld_ifsoftc *mli, int, struct mbuf *, const int);
150 static int	sysctl_mld_gsr(SYSCTL_HANDLER_ARGS);
151 static int	sysctl_mld_ifinfo(SYSCTL_HANDLER_ARGS);
152 
153 /*
154  * Normative references: RFC 2710, RFC 3590, RFC 3810.
155  *
156  * Locking:
157  *  * The MLD subsystem lock ends up being system-wide for the moment,
158  *    but could be per-VIMAGE later on.
159  *  * The permitted lock order is: IN6_MULTI_LOCK, MLD_LOCK, IF_ADDR_LOCK.
160  *    Any may be taken independently; if any are held at the same
161  *    time, the above lock order must be followed.
162  *  * IN6_MULTI_LOCK covers in_multi.
163  *  * MLD_LOCK covers per-link state and any global variables in this file.
164  *  * IF_ADDR_LOCK covers if_multiaddrs, which is used for a variety of
165  *    per-link state iterators.
166  *
167  *  XXX LOR PREVENTION
168  *  A special case for IPv6 is the in6_setscope() routine. ip6_output()
169  *  will not accept an ifp; it wants an embedded scope ID, unlike
170  *  ip_output(), which happily takes the ifp given to it. The embedded
171  *  scope ID is only used by MLD to select the outgoing interface.
172  *
173  *  During interface attach and detach, MLD will take MLD_LOCK *after*
174  *  the IF_AFDATA_LOCK.
175  *  As in6_setscope() takes IF_AFDATA_LOCK then SCOPE_LOCK, we can't call
176  *  it with MLD_LOCK held without triggering an LOR. A netisr with indirect
177  *  dispatch could work around this, but we'd rather not do that, as it
178  *  can introduce other races.
179  *
180  *  As such, we exploit the fact that the scope ID is just the interface
181  *  index, and embed it in the IPv6 destination address accordingly.
182  *  This is potentially NOT VALID for MLDv1 reports, as they
183  *  are always sent to the multicast group itself; as MLDv2
184  *  reports are always sent to ff02::16, this is not an issue
185  *  when MLDv2 is in use.
186  *
187  *  This does not however eliminate the LOR when ip6_output() itself
188  *  calls in6_setscope() internally whilst MLD_LOCK is held. This will
189  *  trigger a LOR warning in WITNESS when the ifnet is detached.
190  *
191  *  The right answer is probably to make IF_AFDATA_LOCK an rwlock, given
192  *  how it's used across the network stack. Here we're simply exploiting
193  *  the fact that MLD runs at a similar layer in the stack to scope6.c.
194  *
195  * VIMAGE:
196  *  * Each in6_multi corresponds to an ifp, and each ifp corresponds
197  *    to a vnet in ifp->if_vnet.
198  */
199 static struct mtx		 mld_mtx;
200 static MALLOC_DEFINE(M_MLD, "mld", "mld state");
201 
202 #define	MLD_EMBEDSCOPE(pin6, zoneid)					\
203 	if (IN6_IS_SCOPE_LINKLOCAL(pin6) ||				\
204 	    IN6_IS_ADDR_MC_INTFACELOCAL(pin6))				\
205 		(pin6)->s6_addr16[1] = htons((zoneid) & 0xFFFF)		\
206 
207 /*
208  * VIMAGE-wide globals.
209  */
210 VNET_DEFINE_STATIC(struct timeval, mld_gsrdelay) = {10, 0};
211 VNET_DEFINE_STATIC(LIST_HEAD(, mld_ifsoftc), mli_head);
212 VNET_DEFINE_STATIC(int, interface_timers_running6);
213 VNET_DEFINE_STATIC(int, state_change_timers_running6);
214 VNET_DEFINE_STATIC(int, current_state_timers_running6);
215 
216 #define	V_mld_gsrdelay			VNET(mld_gsrdelay)
217 #define	V_mli_head			VNET(mli_head)
218 #define	V_interface_timers_running6	VNET(interface_timers_running6)
219 #define	V_state_change_timers_running6	VNET(state_change_timers_running6)
220 #define	V_current_state_timers_running6	VNET(current_state_timers_running6)
221 
222 SYSCTL_DECL(_net_inet6);	/* Note: Not in any common header. */
223 
224 SYSCTL_NODE(_net_inet6, OID_AUTO, mld, CTLFLAG_RW, 0,
225     "IPv6 Multicast Listener Discovery");
226 
227 /*
228  * Virtualized sysctls.
229  */
230 SYSCTL_PROC(_net_inet6_mld, OID_AUTO, gsrdelay,
231     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
232     &VNET_NAME(mld_gsrdelay.tv_sec), 0, sysctl_mld_gsr, "I",
233     "Rate limit for MLDv2 Group-and-Source queries in seconds");
234 
235 /*
236  * Non-virtualized sysctls.
237  */
238 static SYSCTL_NODE(_net_inet6_mld, OID_AUTO, ifinfo,
239     CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_mld_ifinfo,
240     "Per-interface MLDv2 state");
241 
242 static int	mld_v1enable = 1;
243 SYSCTL_INT(_net_inet6_mld, OID_AUTO, v1enable, CTLFLAG_RWTUN,
244     &mld_v1enable, 0, "Enable fallback to MLDv1");
245 
246 static int	mld_v2enable = 1;
247 SYSCTL_INT(_net_inet6_mld, OID_AUTO, v2enable, CTLFLAG_RWTUN,
248     &mld_v2enable, 0, "Enable MLDv2");
249 
250 static int	mld_use_allow = 1;
251 SYSCTL_INT(_net_inet6_mld, OID_AUTO, use_allow, CTLFLAG_RWTUN,
252     &mld_use_allow, 0, "Use ALLOW/BLOCK for RFC 4604 SSM joins/leaves");
253 
254 /*
255  * Packed Router Alert option structure declaration.
256  */
257 struct mld_raopt {
258 	struct ip6_hbh		hbh;
259 	struct ip6_opt		pad;
260 	struct ip6_opt_router	ra;
261 } __packed;
262 
263 /*
264  * Router Alert hop-by-hop option header.
265  */
266 static struct mld_raopt mld_ra = {
267 	.hbh = { 0, 0 },
268 	.pad = { .ip6o_type = IP6OPT_PADN, 0 },
269 	.ra = {
270 	    .ip6or_type = IP6OPT_ROUTER_ALERT,
271 	    .ip6or_len = IP6OPT_RTALERT_LEN - 2,
272 	    .ip6or_value[0] = ((IP6OPT_RTALERT_MLD >> 8) & 0xFF),
273 	    .ip6or_value[1] = (IP6OPT_RTALERT_MLD & 0xFF)
274 	}
275 };
276 static struct ip6_pktopts mld_po;
277 
278 static __inline void
279 mld_save_context(struct mbuf *m, struct ifnet *ifp)
280 {
281 
282 #ifdef VIMAGE
283 	m->m_pkthdr.PH_loc.ptr = ifp->if_vnet;
284 #endif /* VIMAGE */
285 	m->m_pkthdr.flowid = ifp->if_index;
286 }
287 
288 static __inline void
289 mld_scrub_context(struct mbuf *m)
290 {
291 
292 	m->m_pkthdr.PH_loc.ptr = NULL;
293 	m->m_pkthdr.flowid = 0;
294 }
295 
296 /*
297  * Restore context from a queued output chain.
298  * Return saved ifindex.
299  *
300  * VIMAGE: The assertion is there to make sure that we
301  * actually called CURVNET_SET() with what's in the mbuf chain.
302  */
303 static __inline uint32_t
304 mld_restore_context(struct mbuf *m)
305 {
306 
307 #if defined(VIMAGE) && defined(INVARIANTS)
308 	KASSERT(curvnet == m->m_pkthdr.PH_loc.ptr,
309 	    ("%s: called when curvnet was not restored: cuvnet %p m ptr %p",
310 	    __func__, curvnet, m->m_pkthdr.PH_loc.ptr));
311 #endif
312 	return (m->m_pkthdr.flowid);
313 }
314 
315 /*
316  * Retrieve or set threshold between group-source queries in seconds.
317  *
318  * VIMAGE: Assume curvnet set by caller.
319  * SMPng: NOTE: Serialized by MLD lock.
320  */
321 static int
322 sysctl_mld_gsr(SYSCTL_HANDLER_ARGS)
323 {
324 	int error;
325 	int i;
326 
327 	error = sysctl_wire_old_buffer(req, sizeof(int));
328 	if (error)
329 		return (error);
330 
331 	MLD_LOCK();
332 
333 	i = V_mld_gsrdelay.tv_sec;
334 
335 	error = sysctl_handle_int(oidp, &i, 0, req);
336 	if (error || !req->newptr)
337 		goto out_locked;
338 
339 	if (i < -1 || i >= 60) {
340 		error = EINVAL;
341 		goto out_locked;
342 	}
343 
344 	CTR2(KTR_MLD, "change mld_gsrdelay from %d to %d",
345 	     V_mld_gsrdelay.tv_sec, i);
346 	V_mld_gsrdelay.tv_sec = i;
347 
348 out_locked:
349 	MLD_UNLOCK();
350 	return (error);
351 }
352 
353 /*
354  * Expose struct mld_ifsoftc to userland, keyed by ifindex.
355  * For use by ifmcstat(8).
356  *
357  * SMPng: NOTE: Does an unlocked ifindex space read.
358  * VIMAGE: Assume curvnet set by caller. The node handler itself
359  * is not directly virtualized.
360  */
361 static int
362 sysctl_mld_ifinfo(SYSCTL_HANDLER_ARGS)
363 {
364 	int			*name;
365 	int			 error;
366 	u_int			 namelen;
367 	struct ifnet		*ifp;
368 	struct mld_ifsoftc	*mli;
369 
370 	name = (int *)arg1;
371 	namelen = arg2;
372 
373 	if (req->newptr != NULL)
374 		return (EPERM);
375 
376 	if (namelen != 1)
377 		return (EINVAL);
378 
379 	error = sysctl_wire_old_buffer(req, sizeof(struct mld_ifinfo));
380 	if (error)
381 		return (error);
382 
383 	IN6_MULTI_LOCK();
384 	IN6_MULTI_LIST_LOCK();
385 	MLD_LOCK();
386 
387 	if (name[0] <= 0 || name[0] > V_if_index) {
388 		error = ENOENT;
389 		goto out_locked;
390 	}
391 
392 	error = ENOENT;
393 
394 	ifp = ifnet_byindex(name[0]);
395 	if (ifp == NULL)
396 		goto out_locked;
397 
398 	LIST_FOREACH(mli, &V_mli_head, mli_link) {
399 		if (ifp == mli->mli_ifp) {
400 			struct mld_ifinfo info;
401 
402 			info.mli_version = mli->mli_version;
403 			info.mli_v1_timer = mli->mli_v1_timer;
404 			info.mli_v2_timer = mli->mli_v2_timer;
405 			info.mli_flags = mli->mli_flags;
406 			info.mli_rv = mli->mli_rv;
407 			info.mli_qi = mli->mli_qi;
408 			info.mli_qri = mli->mli_qri;
409 			info.mli_uri = mli->mli_uri;
410 			error = SYSCTL_OUT(req, &info, sizeof(info));
411 			break;
412 		}
413 	}
414 
415 out_locked:
416 	MLD_UNLOCK();
417 	IN6_MULTI_LIST_UNLOCK();
418 	IN6_MULTI_UNLOCK();
419 	return (error);
420 }
421 
422 /*
423  * Dispatch an entire queue of pending packet chains.
424  * VIMAGE: Assumes the vnet pointer has been set.
425  */
426 static void
427 mld_dispatch_queue(struct mbufq *mq, int limit)
428 {
429 	struct mbuf *m;
430 
431 	while ((m = mbufq_dequeue(mq)) != NULL) {
432 		CTR3(KTR_MLD, "%s: dispatch %p from %p", __func__, mq, m);
433 		mld_dispatch_packet(m);
434 		if (--limit == 0)
435 			break;
436 	}
437 }
438 
439 /*
440  * Filter outgoing MLD report state by group.
441  *
442  * Reports are ALWAYS suppressed for ALL-HOSTS (ff02::1)
443  * and node-local addresses. However, kernel and socket consumers
444  * always embed the KAME scope ID in the address provided, so strip it
445  * when performing comparison.
446  * Note: This is not the same as the *multicast* scope.
447  *
448  * Return zero if the given group is one for which MLD reports
449  * should be suppressed, or non-zero if reports should be issued.
450  */
451 static __inline int
452 mld_is_addr_reported(const struct in6_addr *addr)
453 {
454 
455 	KASSERT(IN6_IS_ADDR_MULTICAST(addr), ("%s: not multicast", __func__));
456 
457 	if (IPV6_ADDR_MC_SCOPE(addr) == IPV6_ADDR_SCOPE_NODELOCAL)
458 		return (0);
459 
460 	if (IPV6_ADDR_MC_SCOPE(addr) == IPV6_ADDR_SCOPE_LINKLOCAL) {
461 		struct in6_addr tmp = *addr;
462 		in6_clearscope(&tmp);
463 		if (IN6_ARE_ADDR_EQUAL(&tmp, &in6addr_linklocal_allnodes))
464 			return (0);
465 	}
466 
467 	return (1);
468 }
469 
470 /*
471  * Attach MLD when PF_INET6 is attached to an interface.
472  *
473  * SMPng: Normally called with IF_AFDATA_LOCK held.
474  */
475 struct mld_ifsoftc *
476 mld_domifattach(struct ifnet *ifp)
477 {
478 	struct mld_ifsoftc *mli;
479 
480 	CTR3(KTR_MLD, "%s: called for ifp %p(%s)",
481 	    __func__, ifp, if_name(ifp));
482 
483 	MLD_LOCK();
484 
485 	mli = mli_alloc_locked(ifp);
486 	if (!(ifp->if_flags & IFF_MULTICAST))
487 		mli->mli_flags |= MLIF_SILENT;
488 	if (mld_use_allow)
489 		mli->mli_flags |= MLIF_USEALLOW;
490 
491 	MLD_UNLOCK();
492 
493 	return (mli);
494 }
495 
496 /*
497  * VIMAGE: assume curvnet set by caller.
498  */
499 static struct mld_ifsoftc *
500 mli_alloc_locked(/*const*/ struct ifnet *ifp)
501 {
502 	struct mld_ifsoftc *mli;
503 
504 	MLD_LOCK_ASSERT();
505 
506 	mli = malloc(sizeof(struct mld_ifsoftc), M_MLD, M_NOWAIT|M_ZERO);
507 	if (mli == NULL)
508 		goto out;
509 
510 	mli->mli_ifp = ifp;
511 	mli->mli_version = MLD_VERSION_2;
512 	mli->mli_flags = 0;
513 	mli->mli_rv = MLD_RV_INIT;
514 	mli->mli_qi = MLD_QI_INIT;
515 	mli->mli_qri = MLD_QRI_INIT;
516 	mli->mli_uri = MLD_URI_INIT;
517 	mbufq_init(&mli->mli_gq, MLD_MAX_RESPONSE_PACKETS);
518 
519 	LIST_INSERT_HEAD(&V_mli_head, mli, mli_link);
520 
521 	CTR2(KTR_MLD, "allocate mld_ifsoftc for ifp %p(%s)",
522 	     ifp, if_name(ifp));
523 
524 out:
525 	return (mli);
526 }
527 
528 /*
529  * Hook for ifdetach.
530  *
531  * NOTE: Some finalization tasks need to run before the protocol domain
532  * is detached, but also before the link layer does its cleanup.
533  * Run before link-layer cleanup; cleanup groups, but do not free MLD state.
534  *
535  * SMPng: Caller must hold IN6_MULTI_LOCK().
536  * Must take IF_ADDR_LOCK() to cover if_multiaddrs iterator.
537  * XXX This routine is also bitten by unlocked ifma_protospec access.
538  */
539 void
540 mld_ifdetach(struct ifnet *ifp, struct in6_multi_head *inmh)
541 {
542 	struct epoch_tracker     et;
543 	struct mld_ifsoftc	*mli;
544 	struct ifmultiaddr	*ifma;
545 	struct in6_multi	*inm;
546 
547 	CTR3(KTR_MLD, "%s: called for ifp %p(%s)", __func__, ifp,
548 	    if_name(ifp));
549 
550 	IN6_MULTI_LIST_LOCK_ASSERT();
551 	MLD_LOCK();
552 
553 	mli = MLD_IFINFO(ifp);
554 	IF_ADDR_WLOCK(ifp);
555 	/*
556 	 * Extract list of in6_multi associated with the detaching ifp
557 	 * which the PF_INET6 layer is about to release.
558 	 */
559 	NET_EPOCH_ENTER(et);
560 	CK_STAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
561 		inm = in6m_ifmultiaddr_get_inm(ifma);
562 		if (inm == NULL)
563 			continue;
564 		in6m_disconnect_locked(inmh, inm);
565 
566 		if (mli->mli_version == MLD_VERSION_2) {
567 			in6m_clear_recorded(inm);
568 
569 			/*
570 			 * We need to release the final reference held
571 			 * for issuing the INCLUDE {}.
572 			 */
573 			if (inm->in6m_state == MLD_LEAVING_MEMBER) {
574 				inm->in6m_state = MLD_NOT_MEMBER;
575 				in6m_rele_locked(inmh, inm);
576 			}
577 		}
578 	}
579 	NET_EPOCH_EXIT(et);
580 	IF_ADDR_WUNLOCK(ifp);
581 	MLD_UNLOCK();
582 }
583 
584 /*
585  * Hook for domifdetach.
586  * Runs after link-layer cleanup; free MLD state.
587  *
588  * SMPng: Normally called with IF_AFDATA_LOCK held.
589  */
590 void
591 mld_domifdetach(struct ifnet *ifp)
592 {
593 
594 	CTR3(KTR_MLD, "%s: called for ifp %p(%s)",
595 	    __func__, ifp, if_name(ifp));
596 
597 	MLD_LOCK();
598 	mli_delete_locked(ifp);
599 	MLD_UNLOCK();
600 }
601 
602 static void
603 mli_delete_locked(const struct ifnet *ifp)
604 {
605 	struct mld_ifsoftc *mli, *tmli;
606 
607 	CTR3(KTR_MLD, "%s: freeing mld_ifsoftc for ifp %p(%s)",
608 	    __func__, ifp, if_name(ifp));
609 
610 	MLD_LOCK_ASSERT();
611 
612 	LIST_FOREACH_SAFE(mli, &V_mli_head, mli_link, tmli) {
613 		if (mli->mli_ifp == ifp) {
614 			/*
615 			 * Free deferred General Query responses.
616 			 */
617 			mbufq_drain(&mli->mli_gq);
618 
619 			LIST_REMOVE(mli, mli_link);
620 
621 			free(mli, M_MLD);
622 			return;
623 		}
624 	}
625 }
626 
627 /*
628  * Process a received MLDv1 general or address-specific query.
629  * Assumes that the query header has been pulled up to sizeof(mld_hdr).
630  *
631  * NOTE: Can't be fully const correct as we temporarily embed scope ID in
632  * mld_addr. This is OK as we own the mbuf chain.
633  */
634 static int
635 mld_v1_input_query(struct ifnet *ifp, const struct ip6_hdr *ip6,
636     /*const*/ struct mld_hdr *mld)
637 {
638 	struct epoch_tracker	 et;
639 	struct ifmultiaddr	*ifma;
640 	struct mld_ifsoftc	*mli;
641 	struct in6_multi	*inm;
642 	int			 is_general_query;
643 	uint16_t		 timer;
644 #ifdef KTR
645 	char			 ip6tbuf[INET6_ADDRSTRLEN];
646 #endif
647 
648 	is_general_query = 0;
649 
650 	if (!mld_v1enable) {
651 		CTR3(KTR_MLD, "ignore v1 query %s on ifp %p(%s)",
652 		    ip6_sprintf(ip6tbuf, &mld->mld_addr),
653 		    ifp, if_name(ifp));
654 		return (0);
655 	}
656 
657 	/*
658 	 * RFC3810 Section 6.2: MLD queries must originate from
659 	 * a router's link-local address.
660 	 */
661 	if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
662 		CTR3(KTR_MLD, "ignore v1 query src %s on ifp %p(%s)",
663 		    ip6_sprintf(ip6tbuf, &ip6->ip6_src),
664 		    ifp, if_name(ifp));
665 		return (0);
666 	}
667 
668 	/*
669 	 * Do address field validation upfront before we accept
670 	 * the query.
671 	 */
672 	if (IN6_IS_ADDR_UNSPECIFIED(&mld->mld_addr)) {
673 		/*
674 		 * MLDv1 General Query.
675 		 * If this was not sent to the all-nodes group, ignore it.
676 		 */
677 		struct in6_addr		 dst;
678 
679 		dst = ip6->ip6_dst;
680 		in6_clearscope(&dst);
681 		if (!IN6_ARE_ADDR_EQUAL(&dst, &in6addr_linklocal_allnodes))
682 			return (EINVAL);
683 		is_general_query = 1;
684 	} else {
685 		/*
686 		 * Embed scope ID of receiving interface in MLD query for
687 		 * lookup whilst we don't hold other locks.
688 		 */
689 		in6_setscope(&mld->mld_addr, ifp, NULL);
690 	}
691 
692 	IN6_MULTI_LIST_LOCK();
693 	MLD_LOCK();
694 
695 	/*
696 	 * Switch to MLDv1 host compatibility mode.
697 	 */
698 	mli = MLD_IFINFO(ifp);
699 	KASSERT(mli != NULL, ("%s: no mld_ifsoftc for ifp %p", __func__, ifp));
700 	mld_set_version(mli, MLD_VERSION_1);
701 
702 	timer = (ntohs(mld->mld_maxdelay) * PR_FASTHZ) / MLD_TIMER_SCALE;
703 	if (timer == 0)
704 		timer = 1;
705 
706 	NET_EPOCH_ENTER(et);
707 	if (is_general_query) {
708 		/*
709 		 * For each reporting group joined on this
710 		 * interface, kick the report timer.
711 		 */
712 		CTR2(KTR_MLD, "process v1 general query on ifp %p(%s)",
713 			 ifp, if_name(ifp));
714 		CK_STAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
715 			inm = in6m_ifmultiaddr_get_inm(ifma);
716 			if (inm == NULL)
717 				continue;
718 			mld_v1_update_group(inm, timer);
719 		}
720 	} else {
721 		/*
722 		 * MLDv1 Group-Specific Query.
723 		 * If this is a group-specific MLDv1 query, we need only
724 		 * look up the single group to process it.
725 		 */
726 		inm = in6m_lookup_locked(ifp, &mld->mld_addr);
727 		if (inm != NULL) {
728 			CTR3(KTR_MLD, "process v1 query %s on ifp %p(%s)",
729 			    ip6_sprintf(ip6tbuf, &mld->mld_addr),
730 			    ifp, if_name(ifp));
731 			mld_v1_update_group(inm, timer);
732 		}
733 		/* XXX Clear embedded scope ID as userland won't expect it. */
734 		in6_clearscope(&mld->mld_addr);
735 	}
736 
737 	NET_EPOCH_EXIT(et);
738 	MLD_UNLOCK();
739 	IN6_MULTI_LIST_UNLOCK();
740 
741 	return (0);
742 }
743 
744 /*
745  * Update the report timer on a group in response to an MLDv1 query.
746  *
747  * If we are becoming the reporting member for this group, start the timer.
748  * If we already are the reporting member for this group, and timer is
749  * below the threshold, reset it.
750  *
751  * We may be updating the group for the first time since we switched
752  * to MLDv2. If we are, then we must clear any recorded source lists,
753  * and transition to REPORTING state; the group timer is overloaded
754  * for group and group-source query responses.
755  *
756  * Unlike MLDv2, the delay per group should be jittered
757  * to avoid bursts of MLDv1 reports.
758  */
759 static void
760 mld_v1_update_group(struct in6_multi *inm, const int timer)
761 {
762 #ifdef KTR
763 	char			 ip6tbuf[INET6_ADDRSTRLEN];
764 #endif
765 
766 	CTR4(KTR_MLD, "%s: %s/%s timer=%d", __func__,
767 	    ip6_sprintf(ip6tbuf, &inm->in6m_addr),
768 	    if_name(inm->in6m_ifp), timer);
769 
770 	IN6_MULTI_LIST_LOCK_ASSERT();
771 
772 	switch (inm->in6m_state) {
773 	case MLD_NOT_MEMBER:
774 	case MLD_SILENT_MEMBER:
775 		break;
776 	case MLD_REPORTING_MEMBER:
777 		if (inm->in6m_timer != 0 &&
778 		    inm->in6m_timer <= timer) {
779 			CTR1(KTR_MLD, "%s: REPORTING and timer running, "
780 			    "skipping.", __func__);
781 			break;
782 		}
783 		/* FALLTHROUGH */
784 	case MLD_SG_QUERY_PENDING_MEMBER:
785 	case MLD_G_QUERY_PENDING_MEMBER:
786 	case MLD_IDLE_MEMBER:
787 	case MLD_LAZY_MEMBER:
788 	case MLD_AWAKENING_MEMBER:
789 		CTR1(KTR_MLD, "%s: ->REPORTING", __func__);
790 		inm->in6m_state = MLD_REPORTING_MEMBER;
791 		inm->in6m_timer = MLD_RANDOM_DELAY(timer);
792 		V_current_state_timers_running6 = 1;
793 		break;
794 	case MLD_SLEEPING_MEMBER:
795 		CTR1(KTR_MLD, "%s: ->AWAKENING", __func__);
796 		inm->in6m_state = MLD_AWAKENING_MEMBER;
797 		break;
798 	case MLD_LEAVING_MEMBER:
799 		break;
800 	}
801 }
802 
803 /*
804  * Process a received MLDv2 general, group-specific or
805  * group-and-source-specific query.
806  *
807  * Assumes that the query header has been pulled up to sizeof(mldv2_query).
808  *
809  * Return 0 if successful, otherwise an appropriate error code is returned.
810  */
811 static int
812 mld_v2_input_query(struct ifnet *ifp, const struct ip6_hdr *ip6,
813     struct mbuf *m, const int off, const int icmp6len)
814 {
815 	struct mld_ifsoftc	*mli;
816 	struct mldv2_query	*mld;
817 	struct in6_multi	*inm;
818 	uint32_t		 maxdelay, nsrc, qqi;
819 	int			 is_general_query;
820 	uint16_t		 timer;
821 	uint8_t			 qrv;
822 #ifdef KTR
823 	char			 ip6tbuf[INET6_ADDRSTRLEN];
824 #endif
825 
826 	if (!mld_v2enable) {
827 		CTR3(KTR_MLD, "ignore v2 query src %s on ifp %p(%s)",
828 		    ip6_sprintf(ip6tbuf, &ip6->ip6_src),
829 		    ifp, if_name(ifp));
830 		return (0);
831 	}
832 
833 	/*
834 	 * RFC3810 Section 6.2: MLD queries must originate from
835 	 * a router's link-local address.
836 	 */
837 	if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
838 		CTR3(KTR_MLD, "ignore v1 query src %s on ifp %p(%s)",
839 		    ip6_sprintf(ip6tbuf, &ip6->ip6_src),
840 		    ifp, if_name(ifp));
841 		return (0);
842 	}
843 
844 	is_general_query = 0;
845 
846 	CTR2(KTR_MLD, "input v2 query on ifp %p(%s)", ifp, if_name(ifp));
847 
848 	mld = (struct mldv2_query *)(mtod(m, uint8_t *) + off);
849 
850 	maxdelay = ntohs(mld->mld_maxdelay);	/* in 1/10ths of a second */
851 	if (maxdelay >= 32768) {
852 		maxdelay = (MLD_MRC_MANT(maxdelay) | 0x1000) <<
853 			   (MLD_MRC_EXP(maxdelay) + 3);
854 	}
855 	timer = (maxdelay * PR_FASTHZ) / MLD_TIMER_SCALE;
856 	if (timer == 0)
857 		timer = 1;
858 
859 	qrv = MLD_QRV(mld->mld_misc);
860 	if (qrv < 2) {
861 		CTR3(KTR_MLD, "%s: clamping qrv %d to %d", __func__,
862 		    qrv, MLD_RV_INIT);
863 		qrv = MLD_RV_INIT;
864 	}
865 
866 	qqi = mld->mld_qqi;
867 	if (qqi >= 128) {
868 		qqi = MLD_QQIC_MANT(mld->mld_qqi) <<
869 		     (MLD_QQIC_EXP(mld->mld_qqi) + 3);
870 	}
871 
872 	nsrc = ntohs(mld->mld_numsrc);
873 	if (nsrc > MLD_MAX_GS_SOURCES)
874 		return (EMSGSIZE);
875 	if (icmp6len < sizeof(struct mldv2_query) +
876 	    (nsrc * sizeof(struct in6_addr)))
877 		return (EMSGSIZE);
878 
879 	/*
880 	 * Do further input validation upfront to avoid resetting timers
881 	 * should we need to discard this query.
882 	 */
883 	if (IN6_IS_ADDR_UNSPECIFIED(&mld->mld_addr)) {
884 		/*
885 		 * A general query with a source list has undefined
886 		 * behaviour; discard it.
887 		 */
888 		if (nsrc > 0)
889 			return (EINVAL);
890 		is_general_query = 1;
891 	} else {
892 		/*
893 		 * Embed scope ID of receiving interface in MLD query for
894 		 * lookup whilst we don't hold other locks (due to KAME
895 		 * locking lameness). We own this mbuf chain just now.
896 		 */
897 		in6_setscope(&mld->mld_addr, ifp, NULL);
898 	}
899 
900 	IN6_MULTI_LIST_LOCK();
901 	MLD_LOCK();
902 
903 	mli = MLD_IFINFO(ifp);
904 	KASSERT(mli != NULL, ("%s: no mld_ifsoftc for ifp %p", __func__, ifp));
905 
906 	/*
907 	 * Discard the v2 query if we're in Compatibility Mode.
908 	 * The RFC is pretty clear that hosts need to stay in MLDv1 mode
909 	 * until the Old Version Querier Present timer expires.
910 	 */
911 	if (mli->mli_version != MLD_VERSION_2)
912 		goto out_locked;
913 
914 	mld_set_version(mli, MLD_VERSION_2);
915 	mli->mli_rv = qrv;
916 	mli->mli_qi = qqi;
917 	mli->mli_qri = maxdelay;
918 
919 	CTR4(KTR_MLD, "%s: qrv %d qi %d maxdelay %d", __func__, qrv, qqi,
920 	    maxdelay);
921 
922 	if (is_general_query) {
923 		/*
924 		 * MLDv2 General Query.
925 		 *
926 		 * Schedule a current-state report on this ifp for
927 		 * all groups, possibly containing source lists.
928 		 *
929 		 * If there is a pending General Query response
930 		 * scheduled earlier than the selected delay, do
931 		 * not schedule any other reports.
932 		 * Otherwise, reset the interface timer.
933 		 */
934 		CTR2(KTR_MLD, "process v2 general query on ifp %p(%s)",
935 		    ifp, if_name(ifp));
936 		if (mli->mli_v2_timer == 0 || mli->mli_v2_timer >= timer) {
937 			mli->mli_v2_timer = MLD_RANDOM_DELAY(timer);
938 			V_interface_timers_running6 = 1;
939 		}
940 	} else {
941 		struct epoch_tracker et;
942 
943 		/*
944 		 * MLDv2 Group-specific or Group-and-source-specific Query.
945 		 *
946 		 * Group-source-specific queries are throttled on
947 		 * a per-group basis to defeat denial-of-service attempts.
948 		 * Queries for groups we are not a member of on this
949 		 * link are simply ignored.
950 		 */
951 		NET_EPOCH_ENTER(et);
952 		inm = in6m_lookup_locked(ifp, &mld->mld_addr);
953 		if (inm == NULL) {
954 			NET_EPOCH_EXIT(et);
955 			goto out_locked;
956 		}
957 		if (nsrc > 0) {
958 			if (!ratecheck(&inm->in6m_lastgsrtv,
959 			    &V_mld_gsrdelay)) {
960 				CTR1(KTR_MLD, "%s: GS query throttled.",
961 				    __func__);
962 				NET_EPOCH_EXIT(et);
963 				goto out_locked;
964 			}
965 		}
966 		CTR2(KTR_MLD, "process v2 group query on ifp %p(%s)",
967 		     ifp, if_name(ifp));
968 		/*
969 		 * If there is a pending General Query response
970 		 * scheduled sooner than the selected delay, no
971 		 * further report need be scheduled.
972 		 * Otherwise, prepare to respond to the
973 		 * group-specific or group-and-source query.
974 		 */
975 		if (mli->mli_v2_timer == 0 || mli->mli_v2_timer >= timer)
976 			mld_v2_process_group_query(inm, mli, timer, m, off);
977 
978 		/* XXX Clear embedded scope ID as userland won't expect it. */
979 		in6_clearscope(&mld->mld_addr);
980 		NET_EPOCH_EXIT(et);
981 	}
982 
983 out_locked:
984 	MLD_UNLOCK();
985 	IN6_MULTI_LIST_UNLOCK();
986 
987 	return (0);
988 }
989 
990 /*
991  * Process a received MLDv2 group-specific or group-and-source-specific
992  * query.
993  * Return <0 if any error occurred. Currently this is ignored.
994  */
995 static int
996 mld_v2_process_group_query(struct in6_multi *inm, struct mld_ifsoftc *mli,
997     int timer, struct mbuf *m0, const int off)
998 {
999 	struct mldv2_query	*mld;
1000 	int			 retval;
1001 	uint16_t		 nsrc;
1002 
1003 	IN6_MULTI_LIST_LOCK_ASSERT();
1004 	MLD_LOCK_ASSERT();
1005 
1006 	retval = 0;
1007 	mld = (struct mldv2_query *)(mtod(m0, uint8_t *) + off);
1008 
1009 	switch (inm->in6m_state) {
1010 	case MLD_NOT_MEMBER:
1011 	case MLD_SILENT_MEMBER:
1012 	case MLD_SLEEPING_MEMBER:
1013 	case MLD_LAZY_MEMBER:
1014 	case MLD_AWAKENING_MEMBER:
1015 	case MLD_IDLE_MEMBER:
1016 	case MLD_LEAVING_MEMBER:
1017 		return (retval);
1018 		break;
1019 	case MLD_REPORTING_MEMBER:
1020 	case MLD_G_QUERY_PENDING_MEMBER:
1021 	case MLD_SG_QUERY_PENDING_MEMBER:
1022 		break;
1023 	}
1024 
1025 	nsrc = ntohs(mld->mld_numsrc);
1026 
1027 	/*
1028 	 * Deal with group-specific queries upfront.
1029 	 * If any group query is already pending, purge any recorded
1030 	 * source-list state if it exists, and schedule a query response
1031 	 * for this group-specific query.
1032 	 */
1033 	if (nsrc == 0) {
1034 		if (inm->in6m_state == MLD_G_QUERY_PENDING_MEMBER ||
1035 		    inm->in6m_state == MLD_SG_QUERY_PENDING_MEMBER) {
1036 			in6m_clear_recorded(inm);
1037 			timer = min(inm->in6m_timer, timer);
1038 		}
1039 		inm->in6m_state = MLD_G_QUERY_PENDING_MEMBER;
1040 		inm->in6m_timer = MLD_RANDOM_DELAY(timer);
1041 		V_current_state_timers_running6 = 1;
1042 		return (retval);
1043 	}
1044 
1045 	/*
1046 	 * Deal with the case where a group-and-source-specific query has
1047 	 * been received but a group-specific query is already pending.
1048 	 */
1049 	if (inm->in6m_state == MLD_G_QUERY_PENDING_MEMBER) {
1050 		timer = min(inm->in6m_timer, timer);
1051 		inm->in6m_timer = MLD_RANDOM_DELAY(timer);
1052 		V_current_state_timers_running6 = 1;
1053 		return (retval);
1054 	}
1055 
1056 	/*
1057 	 * Finally, deal with the case where a group-and-source-specific
1058 	 * query has been received, where a response to a previous g-s-r
1059 	 * query exists, or none exists.
1060 	 * In this case, we need to parse the source-list which the Querier
1061 	 * has provided us with and check if we have any source list filter
1062 	 * entries at T1 for these sources. If we do not, there is no need
1063 	 * schedule a report and the query may be dropped.
1064 	 * If we do, we must record them and schedule a current-state
1065 	 * report for those sources.
1066 	 */
1067 	if (inm->in6m_nsrc > 0) {
1068 		struct mbuf		*m;
1069 		uint8_t			*sp;
1070 		int			 i, nrecorded;
1071 		int			 soff;
1072 
1073 		m = m0;
1074 		soff = off + sizeof(struct mldv2_query);
1075 		nrecorded = 0;
1076 		for (i = 0; i < nsrc; i++) {
1077 			sp = mtod(m, uint8_t *) + soff;
1078 			retval = in6m_record_source(inm,
1079 			    (const struct in6_addr *)sp);
1080 			if (retval < 0)
1081 				break;
1082 			nrecorded += retval;
1083 			soff += sizeof(struct in6_addr);
1084 			if (soff >= m->m_len) {
1085 				soff = soff - m->m_len;
1086 				m = m->m_next;
1087 				if (m == NULL)
1088 					break;
1089 			}
1090 		}
1091 		if (nrecorded > 0) {
1092 			CTR1(KTR_MLD,
1093 			    "%s: schedule response to SG query", __func__);
1094 			inm->in6m_state = MLD_SG_QUERY_PENDING_MEMBER;
1095 			inm->in6m_timer = MLD_RANDOM_DELAY(timer);
1096 			V_current_state_timers_running6 = 1;
1097 		}
1098 	}
1099 
1100 	return (retval);
1101 }
1102 
1103 /*
1104  * Process a received MLDv1 host membership report.
1105  * Assumes mld points to mld_hdr in pulled up mbuf chain.
1106  *
1107  * NOTE: Can't be fully const correct as we temporarily embed scope ID in
1108  * mld_addr. This is OK as we own the mbuf chain.
1109  */
1110 static int
1111 mld_v1_input_report(struct ifnet *ifp, const struct ip6_hdr *ip6,
1112     /*const*/ struct mld_hdr *mld)
1113 {
1114 	struct in6_addr		 src, dst;
1115 	struct epoch_tracker	 et;
1116 	struct in6_ifaddr	*ia;
1117 	struct in6_multi	*inm;
1118 #ifdef KTR
1119 	char			 ip6tbuf[INET6_ADDRSTRLEN];
1120 #endif
1121 
1122 	if (!mld_v1enable) {
1123 		CTR3(KTR_MLD, "ignore v1 report %s on ifp %p(%s)",
1124 		    ip6_sprintf(ip6tbuf, &mld->mld_addr),
1125 		    ifp, if_name(ifp));
1126 		return (0);
1127 	}
1128 
1129 	if (ifp->if_flags & IFF_LOOPBACK)
1130 		return (0);
1131 
1132 	/*
1133 	 * MLDv1 reports must originate from a host's link-local address,
1134 	 * or the unspecified address (when booting).
1135 	 */
1136 	src = ip6->ip6_src;
1137 	in6_clearscope(&src);
1138 	if (!IN6_IS_SCOPE_LINKLOCAL(&src) && !IN6_IS_ADDR_UNSPECIFIED(&src)) {
1139 		CTR3(KTR_MLD, "ignore v1 query src %s on ifp %p(%s)",
1140 		    ip6_sprintf(ip6tbuf, &ip6->ip6_src),
1141 		    ifp, if_name(ifp));
1142 		return (EINVAL);
1143 	}
1144 
1145 	/*
1146 	 * RFC2710 Section 4: MLDv1 reports must pertain to a multicast
1147 	 * group, and must be directed to the group itself.
1148 	 */
1149 	dst = ip6->ip6_dst;
1150 	in6_clearscope(&dst);
1151 	if (!IN6_IS_ADDR_MULTICAST(&mld->mld_addr) ||
1152 	    !IN6_ARE_ADDR_EQUAL(&mld->mld_addr, &dst)) {
1153 		CTR3(KTR_MLD, "ignore v1 query dst %s on ifp %p(%s)",
1154 		    ip6_sprintf(ip6tbuf, &ip6->ip6_dst),
1155 		    ifp, if_name(ifp));
1156 		return (EINVAL);
1157 	}
1158 
1159 	/*
1160 	 * Make sure we don't hear our own membership report, as fast
1161 	 * leave requires knowing that we are the only member of a
1162 	 * group. Assume we used the link-local address if available,
1163 	 * otherwise look for ::.
1164 	 *
1165 	 * XXX Note that scope ID comparison is needed for the address
1166 	 * returned by in6ifa_ifpforlinklocal(), but SHOULD NOT be
1167 	 * performed for the on-wire address.
1168 	 */
1169 	ia = in6ifa_ifpforlinklocal(ifp, IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
1170 	if ((ia && IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, IA6_IN6(ia))) ||
1171 	    (ia == NULL && IN6_IS_ADDR_UNSPECIFIED(&src))) {
1172 		if (ia != NULL)
1173 			ifa_free(&ia->ia_ifa);
1174 		return (0);
1175 	}
1176 	if (ia != NULL)
1177 		ifa_free(&ia->ia_ifa);
1178 
1179 	CTR3(KTR_MLD, "process v1 report %s on ifp %p(%s)",
1180 	    ip6_sprintf(ip6tbuf, &mld->mld_addr), ifp, if_name(ifp));
1181 
1182 	/*
1183 	 * Embed scope ID of receiving interface in MLD query for lookup
1184 	 * whilst we don't hold other locks (due to KAME locking lameness).
1185 	 */
1186 	if (!IN6_IS_ADDR_UNSPECIFIED(&mld->mld_addr))
1187 		in6_setscope(&mld->mld_addr, ifp, NULL);
1188 
1189 	IN6_MULTI_LIST_LOCK();
1190 	MLD_LOCK();
1191 	NET_EPOCH_ENTER(et);
1192 
1193 	/*
1194 	 * MLDv1 report suppression.
1195 	 * If we are a member of this group, and our membership should be
1196 	 * reported, and our group timer is pending or about to be reset,
1197 	 * stop our group timer by transitioning to the 'lazy' state.
1198 	 */
1199 	inm = in6m_lookup_locked(ifp, &mld->mld_addr);
1200 	if (inm != NULL) {
1201 		struct mld_ifsoftc *mli;
1202 
1203 		mli = inm->in6m_mli;
1204 		KASSERT(mli != NULL,
1205 		    ("%s: no mli for ifp %p", __func__, ifp));
1206 
1207 		/*
1208 		 * If we are in MLDv2 host mode, do not allow the
1209 		 * other host's MLDv1 report to suppress our reports.
1210 		 */
1211 		if (mli->mli_version == MLD_VERSION_2)
1212 			goto out_locked;
1213 
1214 		inm->in6m_timer = 0;
1215 
1216 		switch (inm->in6m_state) {
1217 		case MLD_NOT_MEMBER:
1218 		case MLD_SILENT_MEMBER:
1219 		case MLD_SLEEPING_MEMBER:
1220 			break;
1221 		case MLD_REPORTING_MEMBER:
1222 		case MLD_IDLE_MEMBER:
1223 		case MLD_AWAKENING_MEMBER:
1224 			CTR3(KTR_MLD,
1225 			    "report suppressed for %s on ifp %p(%s)",
1226 			    ip6_sprintf(ip6tbuf, &mld->mld_addr),
1227 			    ifp, if_name(ifp));
1228 		case MLD_LAZY_MEMBER:
1229 			inm->in6m_state = MLD_LAZY_MEMBER;
1230 			break;
1231 		case MLD_G_QUERY_PENDING_MEMBER:
1232 		case MLD_SG_QUERY_PENDING_MEMBER:
1233 		case MLD_LEAVING_MEMBER:
1234 			break;
1235 		}
1236 	}
1237 
1238 out_locked:
1239 	NET_EPOCH_EXIT(et);
1240 	MLD_UNLOCK();
1241 	IN6_MULTI_LIST_UNLOCK();
1242 
1243 	/* XXX Clear embedded scope ID as userland won't expect it. */
1244 	in6_clearscope(&mld->mld_addr);
1245 
1246 	return (0);
1247 }
1248 
1249 /*
1250  * MLD input path.
1251  *
1252  * Assume query messages which fit in a single ICMPv6 message header
1253  * have been pulled up.
1254  * Assume that userland will want to see the message, even if it
1255  * otherwise fails kernel input validation; do not free it.
1256  * Pullup may however free the mbuf chain m if it fails.
1257  *
1258  * Return IPPROTO_DONE if we freed m. Otherwise, return 0.
1259  */
1260 int
1261 mld_input(struct mbuf *m, int off, int icmp6len)
1262 {
1263 	struct ifnet	*ifp;
1264 	struct ip6_hdr	*ip6;
1265 	struct mld_hdr	*mld;
1266 	int		 mldlen;
1267 
1268 	CTR3(KTR_MLD, "%s: called w/mbuf (%p,%d)", __func__, m, off);
1269 
1270 	ifp = m->m_pkthdr.rcvif;
1271 
1272 	ip6 = mtod(m, struct ip6_hdr *);
1273 
1274 	/* Pullup to appropriate size. */
1275 	mld = (struct mld_hdr *)(mtod(m, uint8_t *) + off);
1276 	if (mld->mld_type == MLD_LISTENER_QUERY &&
1277 	    icmp6len >= sizeof(struct mldv2_query)) {
1278 		mldlen = sizeof(struct mldv2_query);
1279 	} else {
1280 		mldlen = sizeof(struct mld_hdr);
1281 	}
1282 	IP6_EXTHDR_GET(mld, struct mld_hdr *, m, off, mldlen);
1283 	if (mld == NULL) {
1284 		ICMP6STAT_INC(icp6s_badlen);
1285 		return (IPPROTO_DONE);
1286 	}
1287 
1288 	/*
1289 	 * Userland needs to see all of this traffic for implementing
1290 	 * the endpoint discovery portion of multicast routing.
1291 	 */
1292 	switch (mld->mld_type) {
1293 	case MLD_LISTENER_QUERY:
1294 		icmp6_ifstat_inc(ifp, ifs6_in_mldquery);
1295 		if (icmp6len == sizeof(struct mld_hdr)) {
1296 			if (mld_v1_input_query(ifp, ip6, mld) != 0)
1297 				return (0);
1298 		} else if (icmp6len >= sizeof(struct mldv2_query)) {
1299 			if (mld_v2_input_query(ifp, ip6, m, off,
1300 			    icmp6len) != 0)
1301 				return (0);
1302 		}
1303 		break;
1304 	case MLD_LISTENER_REPORT:
1305 		icmp6_ifstat_inc(ifp, ifs6_in_mldreport);
1306 		if (mld_v1_input_report(ifp, ip6, mld) != 0)
1307 			return (0);
1308 		break;
1309 	case MLDV2_LISTENER_REPORT:
1310 		icmp6_ifstat_inc(ifp, ifs6_in_mldreport);
1311 		break;
1312 	case MLD_LISTENER_DONE:
1313 		icmp6_ifstat_inc(ifp, ifs6_in_mlddone);
1314 		break;
1315 	default:
1316 		break;
1317 	}
1318 
1319 	return (0);
1320 }
1321 
1322 /*
1323  * Fast timeout handler (global).
1324  * VIMAGE: Timeout handlers are expected to service all vimages.
1325  */
1326 void
1327 mld_fasttimo(void)
1328 {
1329 	struct in6_multi_head inmh;
1330 	VNET_ITERATOR_DECL(vnet_iter);
1331 
1332 	SLIST_INIT(&inmh);
1333 
1334 	VNET_LIST_RLOCK_NOSLEEP();
1335 	VNET_FOREACH(vnet_iter) {
1336 		CURVNET_SET(vnet_iter);
1337 		mld_fasttimo_vnet(&inmh);
1338 		CURVNET_RESTORE();
1339 	}
1340 	VNET_LIST_RUNLOCK_NOSLEEP();
1341 	in6m_release_list_deferred(&inmh);
1342 }
1343 
1344 /*
1345  * Fast timeout handler (per-vnet).
1346  *
1347  * VIMAGE: Assume caller has set up our curvnet.
1348  */
1349 static void
1350 mld_fasttimo_vnet(struct in6_multi_head *inmh)
1351 {
1352 	struct epoch_tracker     et;
1353 	struct mbufq		 scq;	/* State-change packets */
1354 	struct mbufq		 qrq;	/* Query response packets */
1355 	struct ifnet		*ifp;
1356 	struct mld_ifsoftc	*mli;
1357 	struct ifmultiaddr	*ifma;
1358 	struct in6_multi	*inm;
1359 	int			 uri_fasthz;
1360 
1361 	uri_fasthz = 0;
1362 
1363 	/*
1364 	 * Quick check to see if any work needs to be done, in order to
1365 	 * minimize the overhead of fasttimo processing.
1366 	 * SMPng: XXX Unlocked reads.
1367 	 */
1368 	if (!V_current_state_timers_running6 &&
1369 	    !V_interface_timers_running6 &&
1370 	    !V_state_change_timers_running6)
1371 		return;
1372 
1373 	IN6_MULTI_LIST_LOCK();
1374 	MLD_LOCK();
1375 
1376 	/*
1377 	 * MLDv2 General Query response timer processing.
1378 	 */
1379 	if (V_interface_timers_running6) {
1380 		CTR1(KTR_MLD, "%s: interface timers running", __func__);
1381 
1382 		V_interface_timers_running6 = 0;
1383 		LIST_FOREACH(mli, &V_mli_head, mli_link) {
1384 			if (mli->mli_v2_timer == 0) {
1385 				/* Do nothing. */
1386 			} else if (--mli->mli_v2_timer == 0) {
1387 				mld_v2_dispatch_general_query(mli);
1388 			} else {
1389 				V_interface_timers_running6 = 1;
1390 			}
1391 		}
1392 	}
1393 
1394 	if (!V_current_state_timers_running6 &&
1395 	    !V_state_change_timers_running6)
1396 		goto out_locked;
1397 
1398 	V_current_state_timers_running6 = 0;
1399 	V_state_change_timers_running6 = 0;
1400 
1401 	CTR1(KTR_MLD, "%s: state change timers running", __func__);
1402 
1403 	/*
1404 	 * MLD host report and state-change timer processing.
1405 	 * Note: Processing a v2 group timer may remove a node.
1406 	 */
1407 	LIST_FOREACH(mli, &V_mli_head, mli_link) {
1408 		ifp = mli->mli_ifp;
1409 
1410 		if (mli->mli_version == MLD_VERSION_2) {
1411 			uri_fasthz = MLD_RANDOM_DELAY(mli->mli_uri *
1412 			    PR_FASTHZ);
1413 			mbufq_init(&qrq, MLD_MAX_G_GS_PACKETS);
1414 			mbufq_init(&scq, MLD_MAX_STATE_CHANGE_PACKETS);
1415 		}
1416 
1417 		IF_ADDR_WLOCK(ifp);
1418 		NET_EPOCH_ENTER(et);
1419 		CK_STAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
1420 			inm = in6m_ifmultiaddr_get_inm(ifma);
1421 			if (inm == NULL)
1422 				continue;
1423 			switch (mli->mli_version) {
1424 			case MLD_VERSION_1:
1425 				mld_v1_process_group_timer(inmh, inm);
1426 				break;
1427 			case MLD_VERSION_2:
1428 				mld_v2_process_group_timers(inmh, &qrq,
1429 				    &scq, inm, uri_fasthz);
1430 				break;
1431 			}
1432 		}
1433 		IF_ADDR_WUNLOCK(ifp);
1434 
1435 		switch (mli->mli_version) {
1436 		case MLD_VERSION_1:
1437 			/*
1438 			 * Transmit reports for this lifecycle.  This
1439 			 * is done while not holding IF_ADDR_LOCK
1440 			 * since this can call
1441 			 * in6ifa_ifpforlinklocal() which locks
1442 			 * IF_ADDR_LOCK internally as well as
1443 			 * ip6_output() to transmit a packet.
1444 			 */
1445 			while ((inm = SLIST_FIRST(inmh)) != NULL) {
1446 				SLIST_REMOVE_HEAD(inmh, in6m_defer);
1447 				(void)mld_v1_transmit_report(inm,
1448 				    MLD_LISTENER_REPORT);
1449 			}
1450 			break;
1451 		case MLD_VERSION_2:
1452 			mld_dispatch_queue(&qrq, 0);
1453 			mld_dispatch_queue(&scq, 0);
1454 			break;
1455 		}
1456 		NET_EPOCH_EXIT(et);
1457 	}
1458 
1459 out_locked:
1460 	MLD_UNLOCK();
1461 	IN6_MULTI_LIST_UNLOCK();
1462 }
1463 
1464 /*
1465  * Update host report group timer.
1466  * Will update the global pending timer flags.
1467  */
1468 static void
1469 mld_v1_process_group_timer(struct in6_multi_head *inmh, struct in6_multi *inm)
1470 {
1471 	int report_timer_expired;
1472 
1473 	IN6_MULTI_LIST_LOCK_ASSERT();
1474 	MLD_LOCK_ASSERT();
1475 
1476 	if (inm->in6m_timer == 0) {
1477 		report_timer_expired = 0;
1478 	} else if (--inm->in6m_timer == 0) {
1479 		report_timer_expired = 1;
1480 	} else {
1481 		V_current_state_timers_running6 = 1;
1482 		return;
1483 	}
1484 
1485 	switch (inm->in6m_state) {
1486 	case MLD_NOT_MEMBER:
1487 	case MLD_SILENT_MEMBER:
1488 	case MLD_IDLE_MEMBER:
1489 	case MLD_LAZY_MEMBER:
1490 	case MLD_SLEEPING_MEMBER:
1491 	case MLD_AWAKENING_MEMBER:
1492 		break;
1493 	case MLD_REPORTING_MEMBER:
1494 		if (report_timer_expired) {
1495 			inm->in6m_state = MLD_IDLE_MEMBER;
1496 			SLIST_INSERT_HEAD(inmh, inm, in6m_defer);
1497 		}
1498 		break;
1499 	case MLD_G_QUERY_PENDING_MEMBER:
1500 	case MLD_SG_QUERY_PENDING_MEMBER:
1501 	case MLD_LEAVING_MEMBER:
1502 		break;
1503 	}
1504 }
1505 
1506 /*
1507  * Update a group's timers for MLDv2.
1508  * Will update the global pending timer flags.
1509  * Note: Unlocked read from mli.
1510  */
1511 static void
1512 mld_v2_process_group_timers(struct in6_multi_head *inmh,
1513     struct mbufq *qrq, struct mbufq *scq,
1514     struct in6_multi *inm, const int uri_fasthz)
1515 {
1516 	int query_response_timer_expired;
1517 	int state_change_retransmit_timer_expired;
1518 #ifdef KTR
1519 	char ip6tbuf[INET6_ADDRSTRLEN];
1520 #endif
1521 
1522 	IN6_MULTI_LIST_LOCK_ASSERT();
1523 	MLD_LOCK_ASSERT();
1524 
1525 	query_response_timer_expired = 0;
1526 	state_change_retransmit_timer_expired = 0;
1527 
1528 	/*
1529 	 * During a transition from compatibility mode back to MLDv2,
1530 	 * a group record in REPORTING state may still have its group
1531 	 * timer active. This is a no-op in this function; it is easier
1532 	 * to deal with it here than to complicate the slow-timeout path.
1533 	 */
1534 	if (inm->in6m_timer == 0) {
1535 		query_response_timer_expired = 0;
1536 	} else if (--inm->in6m_timer == 0) {
1537 		query_response_timer_expired = 1;
1538 	} else {
1539 		V_current_state_timers_running6 = 1;
1540 	}
1541 
1542 	if (inm->in6m_sctimer == 0) {
1543 		state_change_retransmit_timer_expired = 0;
1544 	} else if (--inm->in6m_sctimer == 0) {
1545 		state_change_retransmit_timer_expired = 1;
1546 	} else {
1547 		V_state_change_timers_running6 = 1;
1548 	}
1549 
1550 	/* We are in fasttimo, so be quick about it. */
1551 	if (!state_change_retransmit_timer_expired &&
1552 	    !query_response_timer_expired)
1553 		return;
1554 
1555 	switch (inm->in6m_state) {
1556 	case MLD_NOT_MEMBER:
1557 	case MLD_SILENT_MEMBER:
1558 	case MLD_SLEEPING_MEMBER:
1559 	case MLD_LAZY_MEMBER:
1560 	case MLD_AWAKENING_MEMBER:
1561 	case MLD_IDLE_MEMBER:
1562 		break;
1563 	case MLD_G_QUERY_PENDING_MEMBER:
1564 	case MLD_SG_QUERY_PENDING_MEMBER:
1565 		/*
1566 		 * Respond to a previously pending Group-Specific
1567 		 * or Group-and-Source-Specific query by enqueueing
1568 		 * the appropriate Current-State report for
1569 		 * immediate transmission.
1570 		 */
1571 		if (query_response_timer_expired) {
1572 			int retval;
1573 
1574 			retval = mld_v2_enqueue_group_record(qrq, inm, 0, 1,
1575 			    (inm->in6m_state == MLD_SG_QUERY_PENDING_MEMBER),
1576 			    0);
1577 			CTR2(KTR_MLD, "%s: enqueue record = %d",
1578 			    __func__, retval);
1579 			inm->in6m_state = MLD_REPORTING_MEMBER;
1580 			in6m_clear_recorded(inm);
1581 		}
1582 		/* FALLTHROUGH */
1583 	case MLD_REPORTING_MEMBER:
1584 	case MLD_LEAVING_MEMBER:
1585 		if (state_change_retransmit_timer_expired) {
1586 			/*
1587 			 * State-change retransmission timer fired.
1588 			 * If there are any further pending retransmissions,
1589 			 * set the global pending state-change flag, and
1590 			 * reset the timer.
1591 			 */
1592 			if (--inm->in6m_scrv > 0) {
1593 				inm->in6m_sctimer = uri_fasthz;
1594 				V_state_change_timers_running6 = 1;
1595 			}
1596 			/*
1597 			 * Retransmit the previously computed state-change
1598 			 * report. If there are no further pending
1599 			 * retransmissions, the mbuf queue will be consumed.
1600 			 * Update T0 state to T1 as we have now sent
1601 			 * a state-change.
1602 			 */
1603 			(void)mld_v2_merge_state_changes(inm, scq);
1604 
1605 			in6m_commit(inm);
1606 			CTR3(KTR_MLD, "%s: T1 -> T0 for %s/%s", __func__,
1607 			    ip6_sprintf(ip6tbuf, &inm->in6m_addr),
1608 			    if_name(inm->in6m_ifp));
1609 
1610 			/*
1611 			 * If we are leaving the group for good, make sure
1612 			 * we release MLD's reference to it.
1613 			 * This release must be deferred using a SLIST,
1614 			 * as we are called from a loop which traverses
1615 			 * the in_ifmultiaddr TAILQ.
1616 			 */
1617 			if (inm->in6m_state == MLD_LEAVING_MEMBER &&
1618 			    inm->in6m_scrv == 0) {
1619 				inm->in6m_state = MLD_NOT_MEMBER;
1620 				in6m_disconnect_locked(inmh, inm);
1621 				in6m_rele_locked(inmh, inm);
1622 			}
1623 		}
1624 		break;
1625 	}
1626 }
1627 
1628 /*
1629  * Switch to a different version on the given interface,
1630  * as per Section 9.12.
1631  */
1632 static void
1633 mld_set_version(struct mld_ifsoftc *mli, const int version)
1634 {
1635 	int old_version_timer;
1636 
1637 	MLD_LOCK_ASSERT();
1638 
1639 	CTR4(KTR_MLD, "%s: switching to v%d on ifp %p(%s)", __func__,
1640 	    version, mli->mli_ifp, if_name(mli->mli_ifp));
1641 
1642 	if (version == MLD_VERSION_1) {
1643 		/*
1644 		 * Compute the "Older Version Querier Present" timer as per
1645 		 * Section 9.12.
1646 		 */
1647 		old_version_timer = (mli->mli_rv * mli->mli_qi) + mli->mli_qri;
1648 		old_version_timer *= PR_SLOWHZ;
1649 		mli->mli_v1_timer = old_version_timer;
1650 	}
1651 
1652 	if (mli->mli_v1_timer > 0 && mli->mli_version != MLD_VERSION_1) {
1653 		mli->mli_version = MLD_VERSION_1;
1654 		mld_v2_cancel_link_timers(mli);
1655 	}
1656 }
1657 
1658 /*
1659  * Cancel pending MLDv2 timers for the given link and all groups
1660  * joined on it; state-change, general-query, and group-query timers.
1661  */
1662 static void
1663 mld_v2_cancel_link_timers(struct mld_ifsoftc *mli)
1664 {
1665 	struct epoch_tracker	 et;
1666 	struct in6_multi_head	 inmh;
1667 	struct ifmultiaddr	*ifma;
1668 	struct ifnet		*ifp;
1669 	struct in6_multi	*inm;
1670 
1671 	CTR3(KTR_MLD, "%s: cancel v2 timers on ifp %p(%s)", __func__,
1672 	    mli->mli_ifp, if_name(mli->mli_ifp));
1673 
1674 	SLIST_INIT(&inmh);
1675 	IN6_MULTI_LIST_LOCK_ASSERT();
1676 	MLD_LOCK_ASSERT();
1677 
1678 	/*
1679 	 * Fast-track this potentially expensive operation
1680 	 * by checking all the global 'timer pending' flags.
1681 	 */
1682 	if (!V_interface_timers_running6 &&
1683 	    !V_state_change_timers_running6 &&
1684 	    !V_current_state_timers_running6)
1685 		return;
1686 
1687 	mli->mli_v2_timer = 0;
1688 
1689 	ifp = mli->mli_ifp;
1690 
1691 	IF_ADDR_WLOCK(ifp);
1692 	NET_EPOCH_ENTER(et);
1693 	CK_STAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
1694 		inm = in6m_ifmultiaddr_get_inm(ifma);
1695 		if (inm == NULL)
1696 			continue;
1697 		switch (inm->in6m_state) {
1698 		case MLD_NOT_MEMBER:
1699 		case MLD_SILENT_MEMBER:
1700 		case MLD_IDLE_MEMBER:
1701 		case MLD_LAZY_MEMBER:
1702 		case MLD_SLEEPING_MEMBER:
1703 		case MLD_AWAKENING_MEMBER:
1704 			break;
1705 		case MLD_LEAVING_MEMBER:
1706 			/*
1707 			 * If we are leaving the group and switching
1708 			 * version, we need to release the final
1709 			 * reference held for issuing the INCLUDE {}.
1710 			 */
1711 			in6m_rele_locked(&inmh, inm);
1712 			/* FALLTHROUGH */
1713 		case MLD_G_QUERY_PENDING_MEMBER:
1714 		case MLD_SG_QUERY_PENDING_MEMBER:
1715 			in6m_clear_recorded(inm);
1716 			/* FALLTHROUGH */
1717 		case MLD_REPORTING_MEMBER:
1718 			inm->in6m_sctimer = 0;
1719 			inm->in6m_timer = 0;
1720 			inm->in6m_state = MLD_REPORTING_MEMBER;
1721 			/*
1722 			 * Free any pending MLDv2 state-change records.
1723 			 */
1724 			mbufq_drain(&inm->in6m_scq);
1725 			break;
1726 		}
1727 	}
1728 	NET_EPOCH_EXIT(et);
1729 	IF_ADDR_WUNLOCK(ifp);
1730 	in6m_release_list_deferred(&inmh);
1731 }
1732 
1733 /*
1734  * Global slowtimo handler.
1735  * VIMAGE: Timeout handlers are expected to service all vimages.
1736  */
1737 void
1738 mld_slowtimo(void)
1739 {
1740 	VNET_ITERATOR_DECL(vnet_iter);
1741 
1742 	VNET_LIST_RLOCK_NOSLEEP();
1743 	VNET_FOREACH(vnet_iter) {
1744 		CURVNET_SET(vnet_iter);
1745 		mld_slowtimo_vnet();
1746 		CURVNET_RESTORE();
1747 	}
1748 	VNET_LIST_RUNLOCK_NOSLEEP();
1749 }
1750 
1751 /*
1752  * Per-vnet slowtimo handler.
1753  */
1754 static void
1755 mld_slowtimo_vnet(void)
1756 {
1757 	struct mld_ifsoftc *mli;
1758 
1759 	MLD_LOCK();
1760 
1761 	LIST_FOREACH(mli, &V_mli_head, mli_link) {
1762 		mld_v1_process_querier_timers(mli);
1763 	}
1764 
1765 	MLD_UNLOCK();
1766 }
1767 
1768 /*
1769  * Update the Older Version Querier Present timers for a link.
1770  * See Section 9.12 of RFC 3810.
1771  */
1772 static void
1773 mld_v1_process_querier_timers(struct mld_ifsoftc *mli)
1774 {
1775 
1776 	MLD_LOCK_ASSERT();
1777 
1778 	if (mli->mli_version != MLD_VERSION_2 && --mli->mli_v1_timer == 0) {
1779 		/*
1780 		 * MLDv1 Querier Present timer expired; revert to MLDv2.
1781 		 */
1782 		CTR5(KTR_MLD,
1783 		    "%s: transition from v%d -> v%d on %p(%s)",
1784 		    __func__, mli->mli_version, MLD_VERSION_2,
1785 		    mli->mli_ifp, if_name(mli->mli_ifp));
1786 		mli->mli_version = MLD_VERSION_2;
1787 	}
1788 }
1789 
1790 /*
1791  * Transmit an MLDv1 report immediately.
1792  */
1793 static int
1794 mld_v1_transmit_report(struct in6_multi *in6m, const int type)
1795 {
1796 	struct ifnet		*ifp;
1797 	struct in6_ifaddr	*ia;
1798 	struct ip6_hdr		*ip6;
1799 	struct mbuf		*mh, *md;
1800 	struct mld_hdr		*mld;
1801 
1802 	IN6_MULTI_LIST_LOCK_ASSERT();
1803 	MLD_LOCK_ASSERT();
1804 
1805 	ifp = in6m->in6m_ifp;
1806 	/* in process of being freed */
1807 	if (ifp == NULL)
1808 		return (0);
1809 	ia = in6ifa_ifpforlinklocal(ifp, IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
1810 	/* ia may be NULL if link-local address is tentative. */
1811 
1812 	mh = m_gethdr(M_NOWAIT, MT_DATA);
1813 	if (mh == NULL) {
1814 		if (ia != NULL)
1815 			ifa_free(&ia->ia_ifa);
1816 		return (ENOMEM);
1817 	}
1818 	md = m_get(M_NOWAIT, MT_DATA);
1819 	if (md == NULL) {
1820 		m_free(mh);
1821 		if (ia != NULL)
1822 			ifa_free(&ia->ia_ifa);
1823 		return (ENOMEM);
1824 	}
1825 	mh->m_next = md;
1826 
1827 	/*
1828 	 * FUTURE: Consider increasing alignment by ETHER_HDR_LEN, so
1829 	 * that ether_output() does not need to allocate another mbuf
1830 	 * for the header in the most common case.
1831 	 */
1832 	M_ALIGN(mh, sizeof(struct ip6_hdr));
1833 	mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld_hdr);
1834 	mh->m_len = sizeof(struct ip6_hdr);
1835 
1836 	ip6 = mtod(mh, struct ip6_hdr *);
1837 	ip6->ip6_flow = 0;
1838 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
1839 	ip6->ip6_vfc |= IPV6_VERSION;
1840 	ip6->ip6_nxt = IPPROTO_ICMPV6;
1841 	ip6->ip6_src = ia ? ia->ia_addr.sin6_addr : in6addr_any;
1842 	ip6->ip6_dst = in6m->in6m_addr;
1843 
1844 	md->m_len = sizeof(struct mld_hdr);
1845 	mld = mtod(md, struct mld_hdr *);
1846 	mld->mld_type = type;
1847 	mld->mld_code = 0;
1848 	mld->mld_cksum = 0;
1849 	mld->mld_maxdelay = 0;
1850 	mld->mld_reserved = 0;
1851 	mld->mld_addr = in6m->in6m_addr;
1852 	in6_clearscope(&mld->mld_addr);
1853 	mld->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6,
1854 	    sizeof(struct ip6_hdr), sizeof(struct mld_hdr));
1855 
1856 	mld_save_context(mh, ifp);
1857 	mh->m_flags |= M_MLDV1;
1858 
1859 	mld_dispatch_packet(mh);
1860 
1861 	if (ia != NULL)
1862 		ifa_free(&ia->ia_ifa);
1863 	return (0);
1864 }
1865 
1866 /*
1867  * Process a state change from the upper layer for the given IPv6 group.
1868  *
1869  * Each socket holds a reference on the in_multi in its own ip_moptions.
1870  * The socket layer will have made the necessary updates to.the group
1871  * state, it is now up to MLD to issue a state change report if there
1872  * has been any change between T0 (when the last state-change was issued)
1873  * and T1 (now).
1874  *
1875  * We use the MLDv2 state machine at group level. The MLd module
1876  * however makes the decision as to which MLD protocol version to speak.
1877  * A state change *from* INCLUDE {} always means an initial join.
1878  * A state change *to* INCLUDE {} always means a final leave.
1879  *
1880  * If delay is non-zero, and the state change is an initial multicast
1881  * join, the state change report will be delayed by 'delay' ticks
1882  * in units of PR_FASTHZ if MLDv1 is active on the link; otherwise
1883  * the initial MLDv2 state change report will be delayed by whichever
1884  * is sooner, a pending state-change timer or delay itself.
1885  *
1886  * VIMAGE: curvnet should have been set by caller, as this routine
1887  * is called from the socket option handlers.
1888  */
1889 int
1890 mld_change_state(struct in6_multi *inm, const int delay)
1891 {
1892 	struct mld_ifsoftc *mli;
1893 	struct ifnet *ifp;
1894 	int error;
1895 
1896 	IN6_MULTI_LIST_LOCK_ASSERT();
1897 
1898 	error = 0;
1899 
1900 	/*
1901 	 * Check if the in6_multi has already been disconnected.
1902 	 */
1903 	if (inm->in6m_ifp == NULL) {
1904 		CTR1(KTR_MLD, "%s: inm is disconnected", __func__);
1905 		return (0);
1906 	}
1907 
1908 	/*
1909 	 * Try to detect if the upper layer just asked us to change state
1910 	 * for an interface which has now gone away.
1911 	 */
1912 	KASSERT(inm->in6m_ifma != NULL, ("%s: no ifma", __func__));
1913 	ifp = inm->in6m_ifma->ifma_ifp;
1914 	if (ifp == NULL)
1915 		return (0);
1916 	/*
1917 	 * Sanity check that netinet6's notion of ifp is the
1918 	 * same as net's.
1919 	 */
1920 	KASSERT(inm->in6m_ifp == ifp, ("%s: bad ifp", __func__));
1921 
1922 	MLD_LOCK();
1923 	mli = MLD_IFINFO(ifp);
1924 	KASSERT(mli != NULL, ("%s: no mld_ifsoftc for ifp %p", __func__, ifp));
1925 
1926 	/*
1927 	 * If we detect a state transition to or from MCAST_UNDEFINED
1928 	 * for this group, then we are starting or finishing an MLD
1929 	 * life cycle for this group.
1930 	 */
1931 	if (inm->in6m_st[1].iss_fmode != inm->in6m_st[0].iss_fmode) {
1932 		CTR3(KTR_MLD, "%s: inm transition %d -> %d", __func__,
1933 		    inm->in6m_st[0].iss_fmode, inm->in6m_st[1].iss_fmode);
1934 		if (inm->in6m_st[0].iss_fmode == MCAST_UNDEFINED) {
1935 			CTR1(KTR_MLD, "%s: initial join", __func__);
1936 			error = mld_initial_join(inm, mli, delay);
1937 			goto out_locked;
1938 		} else if (inm->in6m_st[1].iss_fmode == MCAST_UNDEFINED) {
1939 			CTR1(KTR_MLD, "%s: final leave", __func__);
1940 			mld_final_leave(inm, mli);
1941 			goto out_locked;
1942 		}
1943 	} else {
1944 		CTR1(KTR_MLD, "%s: filter set change", __func__);
1945 	}
1946 
1947 	error = mld_handle_state_change(inm, mli);
1948 
1949 out_locked:
1950 	MLD_UNLOCK();
1951 	return (error);
1952 }
1953 
1954 /*
1955  * Perform the initial join for an MLD group.
1956  *
1957  * When joining a group:
1958  *  If the group should have its MLD traffic suppressed, do nothing.
1959  *  MLDv1 starts sending MLDv1 host membership reports.
1960  *  MLDv2 will schedule an MLDv2 state-change report containing the
1961  *  initial state of the membership.
1962  *
1963  * If the delay argument is non-zero, then we must delay sending the
1964  * initial state change for delay ticks (in units of PR_FASTHZ).
1965  */
1966 static int
1967 mld_initial_join(struct in6_multi *inm, struct mld_ifsoftc *mli,
1968     const int delay)
1969 {
1970 	struct ifnet		*ifp;
1971 	struct mbufq		*mq;
1972 	int			 error, retval, syncstates;
1973 	int			 odelay;
1974 #ifdef KTR
1975 	char			 ip6tbuf[INET6_ADDRSTRLEN];
1976 #endif
1977 
1978 	CTR4(KTR_MLD, "%s: initial join %s on ifp %p(%s)",
1979 	    __func__, ip6_sprintf(ip6tbuf, &inm->in6m_addr),
1980 	    inm->in6m_ifp, if_name(inm->in6m_ifp));
1981 
1982 	error = 0;
1983 	syncstates = 1;
1984 
1985 	ifp = inm->in6m_ifp;
1986 
1987 	IN6_MULTI_LIST_LOCK_ASSERT();
1988 	MLD_LOCK_ASSERT();
1989 
1990 	KASSERT(mli && mli->mli_ifp == ifp, ("%s: inconsistent ifp", __func__));
1991 
1992 	/*
1993 	 * Groups joined on loopback or marked as 'not reported',
1994 	 * enter the MLD_SILENT_MEMBER state and
1995 	 * are never reported in any protocol exchanges.
1996 	 * All other groups enter the appropriate state machine
1997 	 * for the version in use on this link.
1998 	 * A link marked as MLIF_SILENT causes MLD to be completely
1999 	 * disabled for the link.
2000 	 */
2001 	if ((ifp->if_flags & IFF_LOOPBACK) ||
2002 	    (mli->mli_flags & MLIF_SILENT) ||
2003 	    !mld_is_addr_reported(&inm->in6m_addr)) {
2004 		CTR1(KTR_MLD,
2005 "%s: not kicking state machine for silent group", __func__);
2006 		inm->in6m_state = MLD_SILENT_MEMBER;
2007 		inm->in6m_timer = 0;
2008 	} else {
2009 		/*
2010 		 * Deal with overlapping in_multi lifecycle.
2011 		 * If this group was LEAVING, then make sure
2012 		 * we drop the reference we picked up to keep the
2013 		 * group around for the final INCLUDE {} enqueue.
2014 		 */
2015 		if (mli->mli_version == MLD_VERSION_2 &&
2016 		    inm->in6m_state == MLD_LEAVING_MEMBER) {
2017 			inm->in6m_refcount--;
2018 			MPASS(inm->in6m_refcount > 0);
2019 		}
2020 		inm->in6m_state = MLD_REPORTING_MEMBER;
2021 
2022 		switch (mli->mli_version) {
2023 		case MLD_VERSION_1:
2024 			/*
2025 			 * If a delay was provided, only use it if
2026 			 * it is greater than the delay normally
2027 			 * used for an MLDv1 state change report,
2028 			 * and delay sending the initial MLDv1 report
2029 			 * by not transitioning to the IDLE state.
2030 			 */
2031 			odelay = MLD_RANDOM_DELAY(MLD_V1_MAX_RI * PR_FASTHZ);
2032 			if (delay) {
2033 				inm->in6m_timer = max(delay, odelay);
2034 				V_current_state_timers_running6 = 1;
2035 			} else {
2036 				inm->in6m_state = MLD_IDLE_MEMBER;
2037 				error = mld_v1_transmit_report(inm,
2038 				     MLD_LISTENER_REPORT);
2039 				if (error == 0) {
2040 					inm->in6m_timer = odelay;
2041 					V_current_state_timers_running6 = 1;
2042 				}
2043 			}
2044 			break;
2045 
2046 		case MLD_VERSION_2:
2047 			/*
2048 			 * Defer update of T0 to T1, until the first copy
2049 			 * of the state change has been transmitted.
2050 			 */
2051 			syncstates = 0;
2052 
2053 			/*
2054 			 * Immediately enqueue a State-Change Report for
2055 			 * this interface, freeing any previous reports.
2056 			 * Don't kick the timers if there is nothing to do,
2057 			 * or if an error occurred.
2058 			 */
2059 			mq = &inm->in6m_scq;
2060 			mbufq_drain(mq);
2061 			retval = mld_v2_enqueue_group_record(mq, inm, 1,
2062 			    0, 0, (mli->mli_flags & MLIF_USEALLOW));
2063 			CTR2(KTR_MLD, "%s: enqueue record = %d",
2064 			    __func__, retval);
2065 			if (retval <= 0) {
2066 				error = retval * -1;
2067 				break;
2068 			}
2069 
2070 			/*
2071 			 * Schedule transmission of pending state-change
2072 			 * report up to RV times for this link. The timer
2073 			 * will fire at the next mld_fasttimo (~200ms),
2074 			 * giving us an opportunity to merge the reports.
2075 			 *
2076 			 * If a delay was provided to this function, only
2077 			 * use this delay if sooner than the existing one.
2078 			 */
2079 			KASSERT(mli->mli_rv > 1,
2080 			   ("%s: invalid robustness %d", __func__,
2081 			    mli->mli_rv));
2082 			inm->in6m_scrv = mli->mli_rv;
2083 			if (delay) {
2084 				if (inm->in6m_sctimer > 1) {
2085 					inm->in6m_sctimer =
2086 					    min(inm->in6m_sctimer, delay);
2087 				} else
2088 					inm->in6m_sctimer = delay;
2089 			} else
2090 				inm->in6m_sctimer = 1;
2091 			V_state_change_timers_running6 = 1;
2092 
2093 			error = 0;
2094 			break;
2095 		}
2096 	}
2097 
2098 	/*
2099 	 * Only update the T0 state if state change is atomic,
2100 	 * i.e. we don't need to wait for a timer to fire before we
2101 	 * can consider the state change to have been communicated.
2102 	 */
2103 	if (syncstates) {
2104 		in6m_commit(inm);
2105 		CTR3(KTR_MLD, "%s: T1 -> T0 for %s/%s", __func__,
2106 		    ip6_sprintf(ip6tbuf, &inm->in6m_addr),
2107 		    if_name(inm->in6m_ifp));
2108 	}
2109 
2110 	return (error);
2111 }
2112 
2113 /*
2114  * Issue an intermediate state change during the life-cycle.
2115  */
2116 static int
2117 mld_handle_state_change(struct in6_multi *inm, struct mld_ifsoftc *mli)
2118 {
2119 	struct ifnet		*ifp;
2120 	int			 retval;
2121 #ifdef KTR
2122 	char			 ip6tbuf[INET6_ADDRSTRLEN];
2123 #endif
2124 
2125 	CTR4(KTR_MLD, "%s: state change for %s on ifp %p(%s)",
2126 	    __func__, ip6_sprintf(ip6tbuf, &inm->in6m_addr),
2127 	    inm->in6m_ifp, if_name(inm->in6m_ifp));
2128 
2129 	ifp = inm->in6m_ifp;
2130 
2131 	IN6_MULTI_LIST_LOCK_ASSERT();
2132 	MLD_LOCK_ASSERT();
2133 
2134 	KASSERT(mli && mli->mli_ifp == ifp,
2135 	    ("%s: inconsistent ifp", __func__));
2136 
2137 	if ((ifp->if_flags & IFF_LOOPBACK) ||
2138 	    (mli->mli_flags & MLIF_SILENT) ||
2139 	    !mld_is_addr_reported(&inm->in6m_addr) ||
2140 	    (mli->mli_version != MLD_VERSION_2)) {
2141 		if (!mld_is_addr_reported(&inm->in6m_addr)) {
2142 			CTR1(KTR_MLD,
2143 "%s: not kicking state machine for silent group", __func__);
2144 		}
2145 		CTR1(KTR_MLD, "%s: nothing to do", __func__);
2146 		in6m_commit(inm);
2147 		CTR3(KTR_MLD, "%s: T1 -> T0 for %s/%s", __func__,
2148 		    ip6_sprintf(ip6tbuf, &inm->in6m_addr),
2149 		    if_name(inm->in6m_ifp));
2150 		return (0);
2151 	}
2152 
2153 	mbufq_drain(&inm->in6m_scq);
2154 
2155 	retval = mld_v2_enqueue_group_record(&inm->in6m_scq, inm, 1, 0, 0,
2156 	    (mli->mli_flags & MLIF_USEALLOW));
2157 	CTR2(KTR_MLD, "%s: enqueue record = %d", __func__, retval);
2158 	if (retval <= 0)
2159 		return (-retval);
2160 
2161 	/*
2162 	 * If record(s) were enqueued, start the state-change
2163 	 * report timer for this group.
2164 	 */
2165 	inm->in6m_scrv = mli->mli_rv;
2166 	inm->in6m_sctimer = 1;
2167 	V_state_change_timers_running6 = 1;
2168 
2169 	return (0);
2170 }
2171 
2172 /*
2173  * Perform the final leave for a multicast address.
2174  *
2175  * When leaving a group:
2176  *  MLDv1 sends a DONE message, if and only if we are the reporter.
2177  *  MLDv2 enqueues a state-change report containing a transition
2178  *  to INCLUDE {} for immediate transmission.
2179  */
2180 static void
2181 mld_final_leave(struct in6_multi *inm, struct mld_ifsoftc *mli)
2182 {
2183 	int syncstates;
2184 #ifdef KTR
2185 	char ip6tbuf[INET6_ADDRSTRLEN];
2186 #endif
2187 
2188 	syncstates = 1;
2189 
2190 	CTR4(KTR_MLD, "%s: final leave %s on ifp %p(%s)",
2191 	    __func__, ip6_sprintf(ip6tbuf, &inm->in6m_addr),
2192 	    inm->in6m_ifp, if_name(inm->in6m_ifp));
2193 
2194 	IN6_MULTI_LIST_LOCK_ASSERT();
2195 	MLD_LOCK_ASSERT();
2196 
2197 	switch (inm->in6m_state) {
2198 	case MLD_NOT_MEMBER:
2199 	case MLD_SILENT_MEMBER:
2200 	case MLD_LEAVING_MEMBER:
2201 		/* Already leaving or left; do nothing. */
2202 		CTR1(KTR_MLD,
2203 "%s: not kicking state machine for silent group", __func__);
2204 		break;
2205 	case MLD_REPORTING_MEMBER:
2206 	case MLD_IDLE_MEMBER:
2207 	case MLD_G_QUERY_PENDING_MEMBER:
2208 	case MLD_SG_QUERY_PENDING_MEMBER:
2209 		if (mli->mli_version == MLD_VERSION_1) {
2210 #ifdef INVARIANTS
2211 			if (inm->in6m_state == MLD_G_QUERY_PENDING_MEMBER ||
2212 			    inm->in6m_state == MLD_SG_QUERY_PENDING_MEMBER)
2213 			panic("%s: MLDv2 state reached, not MLDv2 mode",
2214 			     __func__);
2215 #endif
2216 			mld_v1_transmit_report(inm, MLD_LISTENER_DONE);
2217 			inm->in6m_state = MLD_NOT_MEMBER;
2218 			V_current_state_timers_running6 = 1;
2219 		} else if (mli->mli_version == MLD_VERSION_2) {
2220 			/*
2221 			 * Stop group timer and all pending reports.
2222 			 * Immediately enqueue a state-change report
2223 			 * TO_IN {} to be sent on the next fast timeout,
2224 			 * giving us an opportunity to merge reports.
2225 			 */
2226 			mbufq_drain(&inm->in6m_scq);
2227 			inm->in6m_timer = 0;
2228 			inm->in6m_scrv = mli->mli_rv;
2229 			CTR4(KTR_MLD, "%s: Leaving %s/%s with %d "
2230 			    "pending retransmissions.", __func__,
2231 			    ip6_sprintf(ip6tbuf, &inm->in6m_addr),
2232 			    if_name(inm->in6m_ifp), inm->in6m_scrv);
2233 			if (inm->in6m_scrv == 0) {
2234 				inm->in6m_state = MLD_NOT_MEMBER;
2235 				inm->in6m_sctimer = 0;
2236 			} else {
2237 				int retval;
2238 
2239 				in6m_acquire_locked(inm);
2240 
2241 				retval = mld_v2_enqueue_group_record(
2242 				    &inm->in6m_scq, inm, 1, 0, 0,
2243 				    (mli->mli_flags & MLIF_USEALLOW));
2244 				KASSERT(retval != 0,
2245 				    ("%s: enqueue record = %d", __func__,
2246 				     retval));
2247 
2248 				inm->in6m_state = MLD_LEAVING_MEMBER;
2249 				inm->in6m_sctimer = 1;
2250 				V_state_change_timers_running6 = 1;
2251 				syncstates = 0;
2252 			}
2253 			break;
2254 		}
2255 		break;
2256 	case MLD_LAZY_MEMBER:
2257 	case MLD_SLEEPING_MEMBER:
2258 	case MLD_AWAKENING_MEMBER:
2259 		/* Our reports are suppressed; do nothing. */
2260 		break;
2261 	}
2262 
2263 	if (syncstates) {
2264 		in6m_commit(inm);
2265 		CTR3(KTR_MLD, "%s: T1 -> T0 for %s/%s", __func__,
2266 		    ip6_sprintf(ip6tbuf, &inm->in6m_addr),
2267 		    if_name(inm->in6m_ifp));
2268 		inm->in6m_st[1].iss_fmode = MCAST_UNDEFINED;
2269 		CTR3(KTR_MLD, "%s: T1 now MCAST_UNDEFINED for %p/%s",
2270 		    __func__, &inm->in6m_addr, if_name(inm->in6m_ifp));
2271 	}
2272 }
2273 
2274 /*
2275  * Enqueue an MLDv2 group record to the given output queue.
2276  *
2277  * If is_state_change is zero, a current-state record is appended.
2278  * If is_state_change is non-zero, a state-change report is appended.
2279  *
2280  * If is_group_query is non-zero, an mbuf packet chain is allocated.
2281  * If is_group_query is zero, and if there is a packet with free space
2282  * at the tail of the queue, it will be appended to providing there
2283  * is enough free space.
2284  * Otherwise a new mbuf packet chain is allocated.
2285  *
2286  * If is_source_query is non-zero, each source is checked to see if
2287  * it was recorded for a Group-Source query, and will be omitted if
2288  * it is not both in-mode and recorded.
2289  *
2290  * If use_block_allow is non-zero, state change reports for initial join
2291  * and final leave, on an inclusive mode group with a source list, will be
2292  * rewritten to use the ALLOW_NEW and BLOCK_OLD record types, respectively.
2293  *
2294  * The function will attempt to allocate leading space in the packet
2295  * for the IPv6+ICMP headers to be prepended without fragmenting the chain.
2296  *
2297  * If successful the size of all data appended to the queue is returned,
2298  * otherwise an error code less than zero is returned, or zero if
2299  * no record(s) were appended.
2300  */
2301 static int
2302 mld_v2_enqueue_group_record(struct mbufq *mq, struct in6_multi *inm,
2303     const int is_state_change, const int is_group_query,
2304     const int is_source_query, const int use_block_allow)
2305 {
2306 	struct mldv2_record	 mr;
2307 	struct mldv2_record	*pmr;
2308 	struct ifnet		*ifp;
2309 	struct ip6_msource	*ims, *nims;
2310 	struct mbuf		*m0, *m, *md;
2311 	int			 is_filter_list_change;
2312 	int			 minrec0len, m0srcs, msrcs, nbytes, off;
2313 	int			 record_has_sources;
2314 	int			 now;
2315 	int			 type;
2316 	uint8_t			 mode;
2317 #ifdef KTR
2318 	char			 ip6tbuf[INET6_ADDRSTRLEN];
2319 #endif
2320 
2321 	IN6_MULTI_LIST_LOCK_ASSERT();
2322 
2323 	ifp = inm->in6m_ifp;
2324 	is_filter_list_change = 0;
2325 	m = NULL;
2326 	m0 = NULL;
2327 	m0srcs = 0;
2328 	msrcs = 0;
2329 	nbytes = 0;
2330 	nims = NULL;
2331 	record_has_sources = 1;
2332 	pmr = NULL;
2333 	type = MLD_DO_NOTHING;
2334 	mode = inm->in6m_st[1].iss_fmode;
2335 
2336 	/*
2337 	 * If we did not transition out of ASM mode during t0->t1,
2338 	 * and there are no source nodes to process, we can skip
2339 	 * the generation of source records.
2340 	 */
2341 	if (inm->in6m_st[0].iss_asm > 0 && inm->in6m_st[1].iss_asm > 0 &&
2342 	    inm->in6m_nsrc == 0)
2343 		record_has_sources = 0;
2344 
2345 	if (is_state_change) {
2346 		/*
2347 		 * Queue a state change record.
2348 		 * If the mode did not change, and there are non-ASM
2349 		 * listeners or source filters present,
2350 		 * we potentially need to issue two records for the group.
2351 		 * If there are ASM listeners, and there was no filter
2352 		 * mode transition of any kind, do nothing.
2353 		 *
2354 		 * If we are transitioning to MCAST_UNDEFINED, we need
2355 		 * not send any sources. A transition to/from this state is
2356 		 * considered inclusive with some special treatment.
2357 		 *
2358 		 * If we are rewriting initial joins/leaves to use
2359 		 * ALLOW/BLOCK, and the group's membership is inclusive,
2360 		 * we need to send sources in all cases.
2361 		 */
2362 		if (mode != inm->in6m_st[0].iss_fmode) {
2363 			if (mode == MCAST_EXCLUDE) {
2364 				CTR1(KTR_MLD, "%s: change to EXCLUDE",
2365 				    __func__);
2366 				type = MLD_CHANGE_TO_EXCLUDE_MODE;
2367 			} else {
2368 				CTR1(KTR_MLD, "%s: change to INCLUDE",
2369 				    __func__);
2370 				if (use_block_allow) {
2371 					/*
2372 					 * XXX
2373 					 * Here we're interested in state
2374 					 * edges either direction between
2375 					 * MCAST_UNDEFINED and MCAST_INCLUDE.
2376 					 * Perhaps we should just check
2377 					 * the group state, rather than
2378 					 * the filter mode.
2379 					 */
2380 					if (mode == MCAST_UNDEFINED) {
2381 						type = MLD_BLOCK_OLD_SOURCES;
2382 					} else {
2383 						type = MLD_ALLOW_NEW_SOURCES;
2384 					}
2385 				} else {
2386 					type = MLD_CHANGE_TO_INCLUDE_MODE;
2387 					if (mode == MCAST_UNDEFINED)
2388 						record_has_sources = 0;
2389 				}
2390 			}
2391 		} else {
2392 			if (record_has_sources) {
2393 				is_filter_list_change = 1;
2394 			} else {
2395 				type = MLD_DO_NOTHING;
2396 			}
2397 		}
2398 	} else {
2399 		/*
2400 		 * Queue a current state record.
2401 		 */
2402 		if (mode == MCAST_EXCLUDE) {
2403 			type = MLD_MODE_IS_EXCLUDE;
2404 		} else if (mode == MCAST_INCLUDE) {
2405 			type = MLD_MODE_IS_INCLUDE;
2406 			KASSERT(inm->in6m_st[1].iss_asm == 0,
2407 			    ("%s: inm %p is INCLUDE but ASM count is %d",
2408 			     __func__, inm, inm->in6m_st[1].iss_asm));
2409 		}
2410 	}
2411 
2412 	/*
2413 	 * Generate the filter list changes using a separate function.
2414 	 */
2415 	if (is_filter_list_change)
2416 		return (mld_v2_enqueue_filter_change(mq, inm));
2417 
2418 	if (type == MLD_DO_NOTHING) {
2419 		CTR3(KTR_MLD, "%s: nothing to do for %s/%s",
2420 		    __func__, ip6_sprintf(ip6tbuf, &inm->in6m_addr),
2421 		    if_name(inm->in6m_ifp));
2422 		return (0);
2423 	}
2424 
2425 	/*
2426 	 * If any sources are present, we must be able to fit at least
2427 	 * one in the trailing space of the tail packet's mbuf,
2428 	 * ideally more.
2429 	 */
2430 	minrec0len = sizeof(struct mldv2_record);
2431 	if (record_has_sources)
2432 		minrec0len += sizeof(struct in6_addr);
2433 
2434 	CTR4(KTR_MLD, "%s: queueing %s for %s/%s", __func__,
2435 	    mld_rec_type_to_str(type),
2436 	    ip6_sprintf(ip6tbuf, &inm->in6m_addr),
2437 	    if_name(inm->in6m_ifp));
2438 
2439 	/*
2440 	 * Check if we have a packet in the tail of the queue for this
2441 	 * group into which the first group record for this group will fit.
2442 	 * Otherwise allocate a new packet.
2443 	 * Always allocate leading space for IP6+RA+ICMPV6+REPORT.
2444 	 * Note: Group records for G/GSR query responses MUST be sent
2445 	 * in their own packet.
2446 	 */
2447 	m0 = mbufq_last(mq);
2448 	if (!is_group_query &&
2449 	    m0 != NULL &&
2450 	    (m0->m_pkthdr.PH_vt.vt_nrecs + 1 <= MLD_V2_REPORT_MAXRECS) &&
2451 	    (m0->m_pkthdr.len + minrec0len) <
2452 	     (ifp->if_mtu - MLD_MTUSPACE)) {
2453 		m0srcs = (ifp->if_mtu - m0->m_pkthdr.len -
2454 			    sizeof(struct mldv2_record)) /
2455 			    sizeof(struct in6_addr);
2456 		m = m0;
2457 		CTR1(KTR_MLD, "%s: use existing packet", __func__);
2458 	} else {
2459 		if (mbufq_full(mq)) {
2460 			CTR1(KTR_MLD, "%s: outbound queue full", __func__);
2461 			return (-ENOMEM);
2462 		}
2463 		m = NULL;
2464 		m0srcs = (ifp->if_mtu - MLD_MTUSPACE -
2465 		    sizeof(struct mldv2_record)) / sizeof(struct in6_addr);
2466 		if (!is_state_change && !is_group_query)
2467 			m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
2468 		if (m == NULL)
2469 			m = m_gethdr(M_NOWAIT, MT_DATA);
2470 		if (m == NULL)
2471 			return (-ENOMEM);
2472 
2473 		mld_save_context(m, ifp);
2474 
2475 		CTR1(KTR_MLD, "%s: allocated first packet", __func__);
2476 	}
2477 
2478 	/*
2479 	 * Append group record.
2480 	 * If we have sources, we don't know how many yet.
2481 	 */
2482 	mr.mr_type = type;
2483 	mr.mr_datalen = 0;
2484 	mr.mr_numsrc = 0;
2485 	mr.mr_addr = inm->in6m_addr;
2486 	in6_clearscope(&mr.mr_addr);
2487 	if (!m_append(m, sizeof(struct mldv2_record), (void *)&mr)) {
2488 		if (m != m0)
2489 			m_freem(m);
2490 		CTR1(KTR_MLD, "%s: m_append() failed.", __func__);
2491 		return (-ENOMEM);
2492 	}
2493 	nbytes += sizeof(struct mldv2_record);
2494 
2495 	/*
2496 	 * Append as many sources as will fit in the first packet.
2497 	 * If we are appending to a new packet, the chain allocation
2498 	 * may potentially use clusters; use m_getptr() in this case.
2499 	 * If we are appending to an existing packet, we need to obtain
2500 	 * a pointer to the group record after m_append(), in case a new
2501 	 * mbuf was allocated.
2502 	 *
2503 	 * Only append sources which are in-mode at t1. If we are
2504 	 * transitioning to MCAST_UNDEFINED state on the group, and
2505 	 * use_block_allow is zero, do not include source entries.
2506 	 * Otherwise, we need to include this source in the report.
2507 	 *
2508 	 * Only report recorded sources in our filter set when responding
2509 	 * to a group-source query.
2510 	 */
2511 	if (record_has_sources) {
2512 		if (m == m0) {
2513 			md = m_last(m);
2514 			pmr = (struct mldv2_record *)(mtod(md, uint8_t *) +
2515 			    md->m_len - nbytes);
2516 		} else {
2517 			md = m_getptr(m, 0, &off);
2518 			pmr = (struct mldv2_record *)(mtod(md, uint8_t *) +
2519 			    off);
2520 		}
2521 		msrcs = 0;
2522 		RB_FOREACH_SAFE(ims, ip6_msource_tree, &inm->in6m_srcs,
2523 		    nims) {
2524 			CTR2(KTR_MLD, "%s: visit node %s", __func__,
2525 			    ip6_sprintf(ip6tbuf, &ims->im6s_addr));
2526 			now = im6s_get_mode(inm, ims, 1);
2527 			CTR2(KTR_MLD, "%s: node is %d", __func__, now);
2528 			if ((now != mode) ||
2529 			    (now == mode &&
2530 			     (!use_block_allow && mode == MCAST_UNDEFINED))) {
2531 				CTR1(KTR_MLD, "%s: skip node", __func__);
2532 				continue;
2533 			}
2534 			if (is_source_query && ims->im6s_stp == 0) {
2535 				CTR1(KTR_MLD, "%s: skip unrecorded node",
2536 				    __func__);
2537 				continue;
2538 			}
2539 			CTR1(KTR_MLD, "%s: append node", __func__);
2540 			if (!m_append(m, sizeof(struct in6_addr),
2541 			    (void *)&ims->im6s_addr)) {
2542 				if (m != m0)
2543 					m_freem(m);
2544 				CTR1(KTR_MLD, "%s: m_append() failed.",
2545 				    __func__);
2546 				return (-ENOMEM);
2547 			}
2548 			nbytes += sizeof(struct in6_addr);
2549 			++msrcs;
2550 			if (msrcs == m0srcs)
2551 				break;
2552 		}
2553 		CTR2(KTR_MLD, "%s: msrcs is %d this packet", __func__,
2554 		    msrcs);
2555 		pmr->mr_numsrc = htons(msrcs);
2556 		nbytes += (msrcs * sizeof(struct in6_addr));
2557 	}
2558 
2559 	if (is_source_query && msrcs == 0) {
2560 		CTR1(KTR_MLD, "%s: no recorded sources to report", __func__);
2561 		if (m != m0)
2562 			m_freem(m);
2563 		return (0);
2564 	}
2565 
2566 	/*
2567 	 * We are good to go with first packet.
2568 	 */
2569 	if (m != m0) {
2570 		CTR1(KTR_MLD, "%s: enqueueing first packet", __func__);
2571 		m->m_pkthdr.PH_vt.vt_nrecs = 1;
2572 		mbufq_enqueue(mq, m);
2573 	} else
2574 		m->m_pkthdr.PH_vt.vt_nrecs++;
2575 
2576 	/*
2577 	 * No further work needed if no source list in packet(s).
2578 	 */
2579 	if (!record_has_sources)
2580 		return (nbytes);
2581 
2582 	/*
2583 	 * Whilst sources remain to be announced, we need to allocate
2584 	 * a new packet and fill out as many sources as will fit.
2585 	 * Always try for a cluster first.
2586 	 */
2587 	while (nims != NULL) {
2588 		if (mbufq_full(mq)) {
2589 			CTR1(KTR_MLD, "%s: outbound queue full", __func__);
2590 			return (-ENOMEM);
2591 		}
2592 		m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
2593 		if (m == NULL)
2594 			m = m_gethdr(M_NOWAIT, MT_DATA);
2595 		if (m == NULL)
2596 			return (-ENOMEM);
2597 		mld_save_context(m, ifp);
2598 		md = m_getptr(m, 0, &off);
2599 		pmr = (struct mldv2_record *)(mtod(md, uint8_t *) + off);
2600 		CTR1(KTR_MLD, "%s: allocated next packet", __func__);
2601 
2602 		if (!m_append(m, sizeof(struct mldv2_record), (void *)&mr)) {
2603 			if (m != m0)
2604 				m_freem(m);
2605 			CTR1(KTR_MLD, "%s: m_append() failed.", __func__);
2606 			return (-ENOMEM);
2607 		}
2608 		m->m_pkthdr.PH_vt.vt_nrecs = 1;
2609 		nbytes += sizeof(struct mldv2_record);
2610 
2611 		m0srcs = (ifp->if_mtu - MLD_MTUSPACE -
2612 		    sizeof(struct mldv2_record)) / sizeof(struct in6_addr);
2613 
2614 		msrcs = 0;
2615 		RB_FOREACH_FROM(ims, ip6_msource_tree, nims) {
2616 			CTR2(KTR_MLD, "%s: visit node %s",
2617 			    __func__, ip6_sprintf(ip6tbuf, &ims->im6s_addr));
2618 			now = im6s_get_mode(inm, ims, 1);
2619 			if ((now != mode) ||
2620 			    (now == mode &&
2621 			     (!use_block_allow && mode == MCAST_UNDEFINED))) {
2622 				CTR1(KTR_MLD, "%s: skip node", __func__);
2623 				continue;
2624 			}
2625 			if (is_source_query && ims->im6s_stp == 0) {
2626 				CTR1(KTR_MLD, "%s: skip unrecorded node",
2627 				    __func__);
2628 				continue;
2629 			}
2630 			CTR1(KTR_MLD, "%s: append node", __func__);
2631 			if (!m_append(m, sizeof(struct in6_addr),
2632 			    (void *)&ims->im6s_addr)) {
2633 				if (m != m0)
2634 					m_freem(m);
2635 				CTR1(KTR_MLD, "%s: m_append() failed.",
2636 				    __func__);
2637 				return (-ENOMEM);
2638 			}
2639 			++msrcs;
2640 			if (msrcs == m0srcs)
2641 				break;
2642 		}
2643 		pmr->mr_numsrc = htons(msrcs);
2644 		nbytes += (msrcs * sizeof(struct in6_addr));
2645 
2646 		CTR1(KTR_MLD, "%s: enqueueing next packet", __func__);
2647 		mbufq_enqueue(mq, m);
2648 	}
2649 
2650 	return (nbytes);
2651 }
2652 
2653 /*
2654  * Type used to mark record pass completion.
2655  * We exploit the fact we can cast to this easily from the
2656  * current filter modes on each ip_msource node.
2657  */
2658 typedef enum {
2659 	REC_NONE = 0x00,	/* MCAST_UNDEFINED */
2660 	REC_ALLOW = 0x01,	/* MCAST_INCLUDE */
2661 	REC_BLOCK = 0x02,	/* MCAST_EXCLUDE */
2662 	REC_FULL = REC_ALLOW | REC_BLOCK
2663 } rectype_t;
2664 
2665 /*
2666  * Enqueue an MLDv2 filter list change to the given output queue.
2667  *
2668  * Source list filter state is held in an RB-tree. When the filter list
2669  * for a group is changed without changing its mode, we need to compute
2670  * the deltas between T0 and T1 for each source in the filter set,
2671  * and enqueue the appropriate ALLOW_NEW/BLOCK_OLD records.
2672  *
2673  * As we may potentially queue two record types, and the entire R-B tree
2674  * needs to be walked at once, we break this out into its own function
2675  * so we can generate a tightly packed queue of packets.
2676  *
2677  * XXX This could be written to only use one tree walk, although that makes
2678  * serializing into the mbuf chains a bit harder. For now we do two walks
2679  * which makes things easier on us, and it may or may not be harder on
2680  * the L2 cache.
2681  *
2682  * If successful the size of all data appended to the queue is returned,
2683  * otherwise an error code less than zero is returned, or zero if
2684  * no record(s) were appended.
2685  */
2686 static int
2687 mld_v2_enqueue_filter_change(struct mbufq *mq, struct in6_multi *inm)
2688 {
2689 	static const int MINRECLEN =
2690 	    sizeof(struct mldv2_record) + sizeof(struct in6_addr);
2691 	struct ifnet		*ifp;
2692 	struct mldv2_record	 mr;
2693 	struct mldv2_record	*pmr;
2694 	struct ip6_msource	*ims, *nims;
2695 	struct mbuf		*m, *m0, *md;
2696 	int			 m0srcs, nbytes, npbytes, off, rsrcs, schanged;
2697 	int			 nallow, nblock;
2698 	uint8_t			 mode, now, then;
2699 	rectype_t		 crt, drt, nrt;
2700 #ifdef KTR
2701 	char			 ip6tbuf[INET6_ADDRSTRLEN];
2702 #endif
2703 
2704 	IN6_MULTI_LIST_LOCK_ASSERT();
2705 
2706 	if (inm->in6m_nsrc == 0 ||
2707 	    (inm->in6m_st[0].iss_asm > 0 && inm->in6m_st[1].iss_asm > 0))
2708 		return (0);
2709 
2710 	ifp = inm->in6m_ifp;			/* interface */
2711 	mode = inm->in6m_st[1].iss_fmode;	/* filter mode at t1 */
2712 	crt = REC_NONE;	/* current group record type */
2713 	drt = REC_NONE;	/* mask of completed group record types */
2714 	nrt = REC_NONE;	/* record type for current node */
2715 	m0srcs = 0;	/* # source which will fit in current mbuf chain */
2716 	npbytes = 0;	/* # of bytes appended this packet */
2717 	nbytes = 0;	/* # of bytes appended to group's state-change queue */
2718 	rsrcs = 0;	/* # sources encoded in current record */
2719 	schanged = 0;	/* # nodes encoded in overall filter change */
2720 	nallow = 0;	/* # of source entries in ALLOW_NEW */
2721 	nblock = 0;	/* # of source entries in BLOCK_OLD */
2722 	nims = NULL;	/* next tree node pointer */
2723 
2724 	/*
2725 	 * For each possible filter record mode.
2726 	 * The first kind of source we encounter tells us which
2727 	 * is the first kind of record we start appending.
2728 	 * If a node transitioned to UNDEFINED at t1, its mode is treated
2729 	 * as the inverse of the group's filter mode.
2730 	 */
2731 	while (drt != REC_FULL) {
2732 		do {
2733 			m0 = mbufq_last(mq);
2734 			if (m0 != NULL &&
2735 			    (m0->m_pkthdr.PH_vt.vt_nrecs + 1 <=
2736 			     MLD_V2_REPORT_MAXRECS) &&
2737 			    (m0->m_pkthdr.len + MINRECLEN) <
2738 			     (ifp->if_mtu - MLD_MTUSPACE)) {
2739 				m = m0;
2740 				m0srcs = (ifp->if_mtu - m0->m_pkthdr.len -
2741 					    sizeof(struct mldv2_record)) /
2742 					    sizeof(struct in6_addr);
2743 				CTR1(KTR_MLD,
2744 				    "%s: use previous packet", __func__);
2745 			} else {
2746 				m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
2747 				if (m == NULL)
2748 					m = m_gethdr(M_NOWAIT, MT_DATA);
2749 				if (m == NULL) {
2750 					CTR1(KTR_MLD,
2751 					    "%s: m_get*() failed", __func__);
2752 					return (-ENOMEM);
2753 				}
2754 				m->m_pkthdr.PH_vt.vt_nrecs = 0;
2755 				mld_save_context(m, ifp);
2756 				m0srcs = (ifp->if_mtu - MLD_MTUSPACE -
2757 				    sizeof(struct mldv2_record)) /
2758 				    sizeof(struct in6_addr);
2759 				npbytes = 0;
2760 				CTR1(KTR_MLD,
2761 				    "%s: allocated new packet", __func__);
2762 			}
2763 			/*
2764 			 * Append the MLD group record header to the
2765 			 * current packet's data area.
2766 			 * Recalculate pointer to free space for next
2767 			 * group record, in case m_append() allocated
2768 			 * a new mbuf or cluster.
2769 			 */
2770 			memset(&mr, 0, sizeof(mr));
2771 			mr.mr_addr = inm->in6m_addr;
2772 			in6_clearscope(&mr.mr_addr);
2773 			if (!m_append(m, sizeof(mr), (void *)&mr)) {
2774 				if (m != m0)
2775 					m_freem(m);
2776 				CTR1(KTR_MLD,
2777 				    "%s: m_append() failed", __func__);
2778 				return (-ENOMEM);
2779 			}
2780 			npbytes += sizeof(struct mldv2_record);
2781 			if (m != m0) {
2782 				/* new packet; offset in chain */
2783 				md = m_getptr(m, npbytes -
2784 				    sizeof(struct mldv2_record), &off);
2785 				pmr = (struct mldv2_record *)(mtod(md,
2786 				    uint8_t *) + off);
2787 			} else {
2788 				/* current packet; offset from last append */
2789 				md = m_last(m);
2790 				pmr = (struct mldv2_record *)(mtod(md,
2791 				    uint8_t *) + md->m_len -
2792 				    sizeof(struct mldv2_record));
2793 			}
2794 			/*
2795 			 * Begin walking the tree for this record type
2796 			 * pass, or continue from where we left off
2797 			 * previously if we had to allocate a new packet.
2798 			 * Only report deltas in-mode at t1.
2799 			 * We need not report included sources as allowed
2800 			 * if we are in inclusive mode on the group,
2801 			 * however the converse is not true.
2802 			 */
2803 			rsrcs = 0;
2804 			if (nims == NULL) {
2805 				nims = RB_MIN(ip6_msource_tree,
2806 				    &inm->in6m_srcs);
2807 			}
2808 			RB_FOREACH_FROM(ims, ip6_msource_tree, nims) {
2809 				CTR2(KTR_MLD, "%s: visit node %s", __func__,
2810 				    ip6_sprintf(ip6tbuf, &ims->im6s_addr));
2811 				now = im6s_get_mode(inm, ims, 1);
2812 				then = im6s_get_mode(inm, ims, 0);
2813 				CTR3(KTR_MLD, "%s: mode: t0 %d, t1 %d",
2814 				    __func__, then, now);
2815 				if (now == then) {
2816 					CTR1(KTR_MLD,
2817 					    "%s: skip unchanged", __func__);
2818 					continue;
2819 				}
2820 				if (mode == MCAST_EXCLUDE &&
2821 				    now == MCAST_INCLUDE) {
2822 					CTR1(KTR_MLD,
2823 					    "%s: skip IN src on EX group",
2824 					    __func__);
2825 					continue;
2826 				}
2827 				nrt = (rectype_t)now;
2828 				if (nrt == REC_NONE)
2829 					nrt = (rectype_t)(~mode & REC_FULL);
2830 				if (schanged++ == 0) {
2831 					crt = nrt;
2832 				} else if (crt != nrt)
2833 					continue;
2834 				if (!m_append(m, sizeof(struct in6_addr),
2835 				    (void *)&ims->im6s_addr)) {
2836 					if (m != m0)
2837 						m_freem(m);
2838 					CTR1(KTR_MLD,
2839 					    "%s: m_append() failed", __func__);
2840 					return (-ENOMEM);
2841 				}
2842 				nallow += !!(crt == REC_ALLOW);
2843 				nblock += !!(crt == REC_BLOCK);
2844 				if (++rsrcs == m0srcs)
2845 					break;
2846 			}
2847 			/*
2848 			 * If we did not append any tree nodes on this
2849 			 * pass, back out of allocations.
2850 			 */
2851 			if (rsrcs == 0) {
2852 				npbytes -= sizeof(struct mldv2_record);
2853 				if (m != m0) {
2854 					CTR1(KTR_MLD,
2855 					    "%s: m_free(m)", __func__);
2856 					m_freem(m);
2857 				} else {
2858 					CTR1(KTR_MLD,
2859 					    "%s: m_adj(m, -mr)", __func__);
2860 					m_adj(m, -((int)sizeof(
2861 					    struct mldv2_record)));
2862 				}
2863 				continue;
2864 			}
2865 			npbytes += (rsrcs * sizeof(struct in6_addr));
2866 			if (crt == REC_ALLOW)
2867 				pmr->mr_type = MLD_ALLOW_NEW_SOURCES;
2868 			else if (crt == REC_BLOCK)
2869 				pmr->mr_type = MLD_BLOCK_OLD_SOURCES;
2870 			pmr->mr_numsrc = htons(rsrcs);
2871 			/*
2872 			 * Count the new group record, and enqueue this
2873 			 * packet if it wasn't already queued.
2874 			 */
2875 			m->m_pkthdr.PH_vt.vt_nrecs++;
2876 			if (m != m0)
2877 				mbufq_enqueue(mq, m);
2878 			nbytes += npbytes;
2879 		} while (nims != NULL);
2880 		drt |= crt;
2881 		crt = (~crt & REC_FULL);
2882 	}
2883 
2884 	CTR3(KTR_MLD, "%s: queued %d ALLOW_NEW, %d BLOCK_OLD", __func__,
2885 	    nallow, nblock);
2886 
2887 	return (nbytes);
2888 }
2889 
2890 static int
2891 mld_v2_merge_state_changes(struct in6_multi *inm, struct mbufq *scq)
2892 {
2893 	struct mbufq	*gq;
2894 	struct mbuf	*m;		/* pending state-change */
2895 	struct mbuf	*m0;		/* copy of pending state-change */
2896 	struct mbuf	*mt;		/* last state-change in packet */
2897 	int		 docopy, domerge;
2898 	u_int		 recslen;
2899 
2900 	docopy = 0;
2901 	domerge = 0;
2902 	recslen = 0;
2903 
2904 	IN6_MULTI_LIST_LOCK_ASSERT();
2905 	MLD_LOCK_ASSERT();
2906 
2907 	/*
2908 	 * If there are further pending retransmissions, make a writable
2909 	 * copy of each queued state-change message before merging.
2910 	 */
2911 	if (inm->in6m_scrv > 0)
2912 		docopy = 1;
2913 
2914 	gq = &inm->in6m_scq;
2915 #ifdef KTR
2916 	if (mbufq_first(gq) == NULL) {
2917 		CTR2(KTR_MLD, "%s: WARNING: queue for inm %p is empty",
2918 		    __func__, inm);
2919 	}
2920 #endif
2921 
2922 	m = mbufq_first(gq);
2923 	while (m != NULL) {
2924 		/*
2925 		 * Only merge the report into the current packet if
2926 		 * there is sufficient space to do so; an MLDv2 report
2927 		 * packet may only contain 65,535 group records.
2928 		 * Always use a simple mbuf chain concatentation to do this,
2929 		 * as large state changes for single groups may have
2930 		 * allocated clusters.
2931 		 */
2932 		domerge = 0;
2933 		mt = mbufq_last(scq);
2934 		if (mt != NULL) {
2935 			recslen = m_length(m, NULL);
2936 
2937 			if ((mt->m_pkthdr.PH_vt.vt_nrecs +
2938 			    m->m_pkthdr.PH_vt.vt_nrecs <=
2939 			    MLD_V2_REPORT_MAXRECS) &&
2940 			    (mt->m_pkthdr.len + recslen <=
2941 			    (inm->in6m_ifp->if_mtu - MLD_MTUSPACE)))
2942 				domerge = 1;
2943 		}
2944 
2945 		if (!domerge && mbufq_full(gq)) {
2946 			CTR2(KTR_MLD,
2947 			    "%s: outbound queue full, skipping whole packet %p",
2948 			    __func__, m);
2949 			mt = m->m_nextpkt;
2950 			if (!docopy)
2951 				m_freem(m);
2952 			m = mt;
2953 			continue;
2954 		}
2955 
2956 		if (!docopy) {
2957 			CTR2(KTR_MLD, "%s: dequeueing %p", __func__, m);
2958 			m0 = mbufq_dequeue(gq);
2959 			m = m0->m_nextpkt;
2960 		} else {
2961 			CTR2(KTR_MLD, "%s: copying %p", __func__, m);
2962 			m0 = m_dup(m, M_NOWAIT);
2963 			if (m0 == NULL)
2964 				return (ENOMEM);
2965 			m0->m_nextpkt = NULL;
2966 			m = m->m_nextpkt;
2967 		}
2968 
2969 		if (!domerge) {
2970 			CTR3(KTR_MLD, "%s: queueing %p to scq %p)",
2971 			    __func__, m0, scq);
2972 			mbufq_enqueue(scq, m0);
2973 		} else {
2974 			struct mbuf *mtl;	/* last mbuf of packet mt */
2975 
2976 			CTR3(KTR_MLD, "%s: merging %p with ifscq tail %p)",
2977 			    __func__, m0, mt);
2978 
2979 			mtl = m_last(mt);
2980 			m0->m_flags &= ~M_PKTHDR;
2981 			mt->m_pkthdr.len += recslen;
2982 			mt->m_pkthdr.PH_vt.vt_nrecs +=
2983 			    m0->m_pkthdr.PH_vt.vt_nrecs;
2984 
2985 			mtl->m_next = m0;
2986 		}
2987 	}
2988 
2989 	return (0);
2990 }
2991 
2992 /*
2993  * Respond to a pending MLDv2 General Query.
2994  */
2995 static void
2996 mld_v2_dispatch_general_query(struct mld_ifsoftc *mli)
2997 {
2998 	struct epoch_tracker	 et;
2999 	struct ifmultiaddr	*ifma;
3000 	struct ifnet		*ifp;
3001 	struct in6_multi	*inm;
3002 	int			 retval;
3003 
3004 	IN6_MULTI_LIST_LOCK_ASSERT();
3005 	MLD_LOCK_ASSERT();
3006 
3007 	KASSERT(mli->mli_version == MLD_VERSION_2,
3008 	    ("%s: called when version %d", __func__, mli->mli_version));
3009 
3010 	/*
3011 	 * Check that there are some packets queued. If so, send them first.
3012 	 * For large number of groups the reply to general query can take
3013 	 * many packets, we should finish sending them before starting of
3014 	 * queuing the new reply.
3015 	 */
3016 	if (mbufq_len(&mli->mli_gq) != 0)
3017 		goto send;
3018 
3019 	ifp = mli->mli_ifp;
3020 
3021 	NET_EPOCH_ENTER(et);
3022 	CK_STAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
3023 		inm = in6m_ifmultiaddr_get_inm(ifma);
3024 		if (inm == NULL)
3025 			continue;
3026 		KASSERT(ifp == inm->in6m_ifp,
3027 		    ("%s: inconsistent ifp", __func__));
3028 
3029 		switch (inm->in6m_state) {
3030 		case MLD_NOT_MEMBER:
3031 		case MLD_SILENT_MEMBER:
3032 			break;
3033 		case MLD_REPORTING_MEMBER:
3034 		case MLD_IDLE_MEMBER:
3035 		case MLD_LAZY_MEMBER:
3036 		case MLD_SLEEPING_MEMBER:
3037 		case MLD_AWAKENING_MEMBER:
3038 			inm->in6m_state = MLD_REPORTING_MEMBER;
3039 			retval = mld_v2_enqueue_group_record(&mli->mli_gq,
3040 			    inm, 0, 0, 0, 0);
3041 			CTR2(KTR_MLD, "%s: enqueue record = %d",
3042 			    __func__, retval);
3043 			break;
3044 		case MLD_G_QUERY_PENDING_MEMBER:
3045 		case MLD_SG_QUERY_PENDING_MEMBER:
3046 		case MLD_LEAVING_MEMBER:
3047 			break;
3048 		}
3049 	}
3050 	NET_EPOCH_EXIT(et);
3051 
3052 send:
3053 	mld_dispatch_queue(&mli->mli_gq, MLD_MAX_RESPONSE_BURST);
3054 
3055 	/*
3056 	 * Slew transmission of bursts over 500ms intervals.
3057 	 */
3058 	if (mbufq_first(&mli->mli_gq) != NULL) {
3059 		mli->mli_v2_timer = 1 + MLD_RANDOM_DELAY(
3060 		    MLD_RESPONSE_BURST_INTERVAL);
3061 		V_interface_timers_running6 = 1;
3062 	}
3063 }
3064 
3065 /*
3066  * Transmit the next pending message in the output queue.
3067  *
3068  * VIMAGE: Needs to store/restore vnet pointer on a per-mbuf-chain basis.
3069  * MRT: Nothing needs to be done, as MLD traffic is always local to
3070  * a link and uses a link-scope multicast address.
3071  */
3072 static void
3073 mld_dispatch_packet(struct mbuf *m)
3074 {
3075 	struct ip6_moptions	 im6o;
3076 	struct ifnet		*ifp;
3077 	struct ifnet		*oifp;
3078 	struct mbuf		*m0;
3079 	struct mbuf		*md;
3080 	struct ip6_hdr		*ip6;
3081 	struct mld_hdr		*mld;
3082 	int			 error;
3083 	int			 off;
3084 	int			 type;
3085 	uint32_t		 ifindex;
3086 
3087 	CTR2(KTR_MLD, "%s: transmit %p", __func__, m);
3088 
3089 	/*
3090 	 * Set VNET image pointer from enqueued mbuf chain
3091 	 * before doing anything else. Whilst we use interface
3092 	 * indexes to guard against interface detach, they are
3093 	 * unique to each VIMAGE and must be retrieved.
3094 	 */
3095 	ifindex = mld_restore_context(m);
3096 
3097 	/*
3098 	 * Check if the ifnet still exists. This limits the scope of
3099 	 * any race in the absence of a global ifp lock for low cost
3100 	 * (an array lookup).
3101 	 */
3102 	ifp = ifnet_byindex(ifindex);
3103 	if (ifp == NULL) {
3104 		CTR3(KTR_MLD, "%s: dropped %p as ifindex %u went away.",
3105 		    __func__, m, ifindex);
3106 		m_freem(m);
3107 		IP6STAT_INC(ip6s_noroute);
3108 		goto out;
3109 	}
3110 
3111 	im6o.im6o_multicast_hlim  = 1;
3112 	im6o.im6o_multicast_loop = (V_ip6_mrouter != NULL);
3113 	im6o.im6o_multicast_ifp = ifp;
3114 
3115 	if (m->m_flags & M_MLDV1) {
3116 		m0 = m;
3117 	} else {
3118 		m0 = mld_v2_encap_report(ifp, m);
3119 		if (m0 == NULL) {
3120 			CTR2(KTR_MLD, "%s: dropped %p", __func__, m);
3121 			IP6STAT_INC(ip6s_odropped);
3122 			goto out;
3123 		}
3124 	}
3125 
3126 	mld_scrub_context(m0);
3127 	m_clrprotoflags(m);
3128 	m0->m_pkthdr.rcvif = V_loif;
3129 
3130 	ip6 = mtod(m0, struct ip6_hdr *);
3131 #if 0
3132 	(void)in6_setscope(&ip6->ip6_dst, ifp, NULL);	/* XXX LOR */
3133 #else
3134 	/*
3135 	 * XXX XXX Break some KPI rules to prevent an LOR which would
3136 	 * occur if we called in6_setscope() at transmission.
3137 	 * See comments at top of file.
3138 	 */
3139 	MLD_EMBEDSCOPE(&ip6->ip6_dst, ifp->if_index);
3140 #endif
3141 
3142 	/*
3143 	 * Retrieve the ICMPv6 type before handoff to ip6_output(),
3144 	 * so we can bump the stats.
3145 	 */
3146 	md = m_getptr(m0, sizeof(struct ip6_hdr), &off);
3147 	mld = (struct mld_hdr *)(mtod(md, uint8_t *) + off);
3148 	type = mld->mld_type;
3149 
3150 	error = ip6_output(m0, &mld_po, NULL, IPV6_UNSPECSRC, &im6o,
3151 	    &oifp, NULL);
3152 	if (error) {
3153 		CTR3(KTR_MLD, "%s: ip6_output(%p) = %d", __func__, m0, error);
3154 		goto out;
3155 	}
3156 	ICMP6STAT_INC(icp6s_outhist[type]);
3157 	if (oifp != NULL) {
3158 		icmp6_ifstat_inc(oifp, ifs6_out_msg);
3159 		switch (type) {
3160 		case MLD_LISTENER_REPORT:
3161 		case MLDV2_LISTENER_REPORT:
3162 			icmp6_ifstat_inc(oifp, ifs6_out_mldreport);
3163 			break;
3164 		case MLD_LISTENER_DONE:
3165 			icmp6_ifstat_inc(oifp, ifs6_out_mlddone);
3166 			break;
3167 		}
3168 	}
3169 out:
3170 	return;
3171 }
3172 
3173 /*
3174  * Encapsulate an MLDv2 report.
3175  *
3176  * KAME IPv6 requires that hop-by-hop options be passed separately,
3177  * and that the IPv6 header be prepended in a separate mbuf.
3178  *
3179  * Returns a pointer to the new mbuf chain head, or NULL if the
3180  * allocation failed.
3181  */
3182 static struct mbuf *
3183 mld_v2_encap_report(struct ifnet *ifp, struct mbuf *m)
3184 {
3185 	struct mbuf		*mh;
3186 	struct mldv2_report	*mld;
3187 	struct ip6_hdr		*ip6;
3188 	struct in6_ifaddr	*ia;
3189 	int			 mldreclen;
3190 
3191 	KASSERT(ifp != NULL, ("%s: null ifp", __func__));
3192 	KASSERT((m->m_flags & M_PKTHDR),
3193 	    ("%s: mbuf chain %p is !M_PKTHDR", __func__, m));
3194 
3195 	/*
3196 	 * RFC3590: OK to send as :: or tentative during DAD.
3197 	 */
3198 	ia = in6ifa_ifpforlinklocal(ifp, IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
3199 	if (ia == NULL)
3200 		CTR1(KTR_MLD, "%s: warning: ia is NULL", __func__);
3201 
3202 	mh = m_gethdr(M_NOWAIT, MT_DATA);
3203 	if (mh == NULL) {
3204 		if (ia != NULL)
3205 			ifa_free(&ia->ia_ifa);
3206 		m_freem(m);
3207 		return (NULL);
3208 	}
3209 	M_ALIGN(mh, sizeof(struct ip6_hdr) + sizeof(struct mldv2_report));
3210 
3211 	mldreclen = m_length(m, NULL);
3212 	CTR2(KTR_MLD, "%s: mldreclen is %d", __func__, mldreclen);
3213 
3214 	mh->m_len = sizeof(struct ip6_hdr) + sizeof(struct mldv2_report);
3215 	mh->m_pkthdr.len = sizeof(struct ip6_hdr) +
3216 	    sizeof(struct mldv2_report) + mldreclen;
3217 
3218 	ip6 = mtod(mh, struct ip6_hdr *);
3219 	ip6->ip6_flow = 0;
3220 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
3221 	ip6->ip6_vfc |= IPV6_VERSION;
3222 	ip6->ip6_nxt = IPPROTO_ICMPV6;
3223 	ip6->ip6_src = ia ? ia->ia_addr.sin6_addr : in6addr_any;
3224 	if (ia != NULL)
3225 		ifa_free(&ia->ia_ifa);
3226 	ip6->ip6_dst = in6addr_linklocal_allv2routers;
3227 	/* scope ID will be set in netisr */
3228 
3229 	mld = (struct mldv2_report *)(ip6 + 1);
3230 	mld->mld_type = MLDV2_LISTENER_REPORT;
3231 	mld->mld_code = 0;
3232 	mld->mld_cksum = 0;
3233 	mld->mld_v2_reserved = 0;
3234 	mld->mld_v2_numrecs = htons(m->m_pkthdr.PH_vt.vt_nrecs);
3235 	m->m_pkthdr.PH_vt.vt_nrecs = 0;
3236 
3237 	mh->m_next = m;
3238 	mld->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6,
3239 	    sizeof(struct ip6_hdr), sizeof(struct mldv2_report) + mldreclen);
3240 	return (mh);
3241 }
3242 
3243 #ifdef KTR
3244 static char *
3245 mld_rec_type_to_str(const int type)
3246 {
3247 
3248 	switch (type) {
3249 		case MLD_CHANGE_TO_EXCLUDE_MODE:
3250 			return "TO_EX";
3251 			break;
3252 		case MLD_CHANGE_TO_INCLUDE_MODE:
3253 			return "TO_IN";
3254 			break;
3255 		case MLD_MODE_IS_EXCLUDE:
3256 			return "MODE_EX";
3257 			break;
3258 		case MLD_MODE_IS_INCLUDE:
3259 			return "MODE_IN";
3260 			break;
3261 		case MLD_ALLOW_NEW_SOURCES:
3262 			return "ALLOW_NEW";
3263 			break;
3264 		case MLD_BLOCK_OLD_SOURCES:
3265 			return "BLOCK_OLD";
3266 			break;
3267 		default:
3268 			break;
3269 	}
3270 	return "unknown";
3271 }
3272 #endif
3273 
3274 static void
3275 mld_init(void *unused __unused)
3276 {
3277 
3278 	CTR1(KTR_MLD, "%s: initializing", __func__);
3279 	MLD_LOCK_INIT();
3280 
3281 	ip6_initpktopts(&mld_po);
3282 	mld_po.ip6po_hlim = 1;
3283 	mld_po.ip6po_hbh = &mld_ra.hbh;
3284 	mld_po.ip6po_prefer_tempaddr = IP6PO_TEMPADDR_NOTPREFER;
3285 	mld_po.ip6po_flags = IP6PO_DONTFRAG;
3286 }
3287 SYSINIT(mld_init, SI_SUB_PROTO_MC, SI_ORDER_MIDDLE, mld_init, NULL);
3288 
3289 static void
3290 mld_uninit(void *unused __unused)
3291 {
3292 
3293 	CTR1(KTR_MLD, "%s: tearing down", __func__);
3294 	MLD_LOCK_DESTROY();
3295 }
3296 SYSUNINIT(mld_uninit, SI_SUB_PROTO_MC, SI_ORDER_MIDDLE, mld_uninit, NULL);
3297 
3298 static void
3299 vnet_mld_init(const void *unused __unused)
3300 {
3301 
3302 	CTR1(KTR_MLD, "%s: initializing", __func__);
3303 
3304 	LIST_INIT(&V_mli_head);
3305 }
3306 VNET_SYSINIT(vnet_mld_init, SI_SUB_PROTO_MC, SI_ORDER_ANY, vnet_mld_init,
3307     NULL);
3308 
3309 static void
3310 vnet_mld_uninit(const void *unused __unused)
3311 {
3312 
3313 	/* This can happen if we shutdown the network stack. */
3314 	CTR1(KTR_MLD, "%s: tearing down", __func__);
3315 }
3316 VNET_SYSUNINIT(vnet_mld_uninit, SI_SUB_PROTO_MC, SI_ORDER_ANY, vnet_mld_uninit,
3317     NULL);
3318 
3319 static int
3320 mld_modevent(module_t mod, int type, void *unused __unused)
3321 {
3322 
3323     switch (type) {
3324     case MOD_LOAD:
3325     case MOD_UNLOAD:
3326 	break;
3327     default:
3328 	return (EOPNOTSUPP);
3329     }
3330     return (0);
3331 }
3332 
3333 static moduledata_t mld_mod = {
3334     "mld",
3335     mld_modevent,
3336     0
3337 };
3338 DECLARE_MODULE(mld, mld_mod, SI_SUB_PROTO_MC, SI_ORDER_ANY);
3339