]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/netinet/igmp.c
xnu-4570.51.1.tar.gz
[apple/xnu.git] / bsd / netinet / igmp.c
index 004ccc9c7a9898c367894d5698e9a3ab1cd91b30..b96b869fa9a7908ccb690e965ba8ae2230857fa7 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2016 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
@@ -25,7 +25,8 @@
  * 
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
-/*
+/*-
+ * Copyright (c) 2007-2009 Bruce Simpson.
  * Copyright (c) 1988 Stephen Deering.
  * Copyright (c) 1992, 1993
  *     The Regents of the University of California.  All rights reserved.
 
 /*
  * Internet Group Management Protocol (IGMP) routines.
+ * [RFC1112, RFC2236, RFC3376]
  *
  * Written by Steve Deering, Stanford, May 1988.
  * Modified by Rosen Sharma, Stanford, Aug 1994.
  * Modified by Bill Fenner, Xerox PARC, Feb 1995.
  * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995.
+ * Significantly rewritten for IGMPv3, VIMAGE, and SMP by Bruce Simpson.
  *
  * MULTICAST Revision: 3.5.1.4
  */
 
+#include <sys/cdefs.h>
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/malloc.h>
 #include <sys/protosw.h>
 #include <sys/kernel.h>
 #include <sys/sysctl.h>
+#include <sys/mcache.h>
+
+#include <libkern/libkern.h>
+#include <kern/zalloc.h>
 
 #include <net/if.h>
 #include <net/route.h>
 #include <netinet/ip_var.h>
 #include <netinet/igmp.h>
 #include <netinet/igmp_var.h>
+#include <netinet/kpi_ipfilter_var.h>
 
-#if CONFIG_MACF_NET
-#include <security/mac_framework.h>
-#endif
+SLIST_HEAD(igmp_inm_relhead, in_multi);
 
-#ifndef __APPLE__
-static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state");
+static void    igi_initvar(struct igmp_ifinfo *, struct ifnet *, int);
+static struct igmp_ifinfo *igi_alloc(int);
+static void    igi_free(struct igmp_ifinfo *);
+static void    igi_delete(const struct ifnet *, struct igmp_inm_relhead *);
+static void    igmp_dispatch_queue(struct igmp_ifinfo *, struct ifqueue *,
+    int, const int);
+static void    igmp_final_leave(struct in_multi *, struct igmp_ifinfo *,
+                   struct igmp_tparams *);
+static int     igmp_handle_state_change(struct in_multi *,
+                   struct igmp_ifinfo *, struct igmp_tparams *);
+static int     igmp_initial_join(struct in_multi *, struct igmp_ifinfo *,
+                   struct igmp_tparams *);
+static int     igmp_input_v1_query(struct ifnet *, const struct ip *,
+                   const struct igmp *);
+static int     igmp_input_v2_query(struct ifnet *, const struct ip *,
+                   const struct igmp *);
+static int     igmp_input_v3_query(struct ifnet *, const struct ip *,
+                   /*const*/ struct igmpv3 *);
+static int     igmp_input_v3_group_query(struct in_multi *,
+                    int, /*const*/ struct igmpv3 *);
+static int     igmp_input_v1_report(struct ifnet *, struct mbuf *,
+                   /*const*/ struct ip *, /*const*/ struct igmp *);
+static int     igmp_input_v2_report(struct ifnet *, struct mbuf *,
+                   /*const*/ struct ip *, /*const*/ struct igmp *);
+static void    igmp_sendpkt(struct mbuf *);
+static __inline__ int  igmp_isgroupreported(const struct in_addr);
+static struct mbuf *igmp_ra_alloc(void);
+#ifdef IGMP_DEBUG
+static const char *igmp_rec_type_to_str(const int);
 #endif
+static uint32_t        igmp_set_version(struct igmp_ifinfo *, const int);
+static void    igmp_flush_relq(struct igmp_ifinfo *,
+    struct igmp_inm_relhead *);
+static int     igmp_v1v2_queue_report(struct in_multi *, const int);
+static void    igmp_v1v2_process_group_timer(struct in_multi *, const int);
+static void    igmp_v1v2_process_querier_timers(struct igmp_ifinfo *);
+static uint32_t        igmp_v2_update_group(struct in_multi *, const int);
+static void    igmp_v3_cancel_link_timers(struct igmp_ifinfo *);
+static uint32_t        igmp_v3_dispatch_general_query(struct igmp_ifinfo *);
+static struct mbuf *
+               igmp_v3_encap_report(struct ifnet *, struct mbuf *);
+static int     igmp_v3_enqueue_group_record(struct ifqueue *,
+                   struct in_multi *, const int, const int, const int);
+static int     igmp_v3_enqueue_filter_change(struct ifqueue *,
+                   struct in_multi *);
+static void    igmp_v3_process_group_timers(struct igmp_ifinfo *,
+                   struct ifqueue *, struct ifqueue *, struct in_multi *,
+                   const int);
+static int     igmp_v3_merge_state_changes(struct in_multi *,
+                   struct ifqueue *);
+static void    igmp_v3_suppress_group_record(struct in_multi *);
+static int     sysctl_igmp_ifinfo SYSCTL_HANDLER_ARGS;
+static int     sysctl_igmp_gsr SYSCTL_HANDLER_ARGS;
+static int     sysctl_igmp_default_version SYSCTL_HANDLER_ARGS;
+
+static int igmp_timeout_run;           /* IGMP timer is scheduled to run */
+static void igmp_timeout(void *);
+static void igmp_sched_timeout(void);
+
+static struct mbuf *m_raopt;           /* Router Alert option */
+
+static int querier_present_timers_running;     /* IGMPv1/v2 older version
+                                                * querier present */
+static int interface_timers_running;           /* IGMPv3 general
+                                                * query response */
+static int state_change_timers_running;                /* IGMPv3 state-change
+                                                * retransmit */
+static int current_state_timers_running;       /* IGMPv1/v2 host
+                                                * report; IGMPv3 g/sg
+                                                * query response */
+
+/*
+ * Subsystem lock macros.
+ */
+#define        IGMP_LOCK()                     \
+       lck_mtx_lock(&igmp_mtx)
+#define        IGMP_LOCK_ASSERT_HELD()         \
+       LCK_MTX_ASSERT(&igmp_mtx, LCK_MTX_ASSERT_OWNED)
+#define        IGMP_LOCK_ASSERT_NOTHELD()      \
+       LCK_MTX_ASSERT(&igmp_mtx, LCK_MTX_ASSERT_NOTOWNED)
+#define        IGMP_UNLOCK()                   \
+       lck_mtx_unlock(&igmp_mtx)
+
+static LIST_HEAD(, igmp_ifinfo) igi_head;
+static struct igmpstat_v3 igmpstat_v3 = {
+       .igps_version = IGPS_VERSION_3,
+       .igps_len = sizeof(struct igmpstat_v3),
+};
+static struct igmpstat igmpstat; /* old IGMPv2 stats structure */
+static struct timeval igmp_gsrdelay = {10, 0};
+
+static int igmp_recvifkludge = 1;
+static int igmp_sendra = 1;
+static int igmp_sendlocal = 1;
+static int igmp_v1enable = 1;
+static int igmp_v2enable = 1;
+static int igmp_legacysupp = 0;
+static int igmp_default_version = IGMP_VERSION_3;
 
-static struct router_info *
-               find_rti(struct ifnet *ifp, int wait);
+SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RD | CTLFLAG_LOCKED,
+    &igmpstat, igmpstat, "");
+SYSCTL_STRUCT(_net_inet_igmp, OID_AUTO, v3stats,
+    CTLFLAG_RD | CTLFLAG_LOCKED, &igmpstat_v3, igmpstat_v3, "");
+SYSCTL_INT(_net_inet_igmp, OID_AUTO, recvifkludge, CTLFLAG_RW | CTLFLAG_LOCKED,
+    &igmp_recvifkludge, 0,
+    "Rewrite IGMPv1/v2 reports from 0.0.0.0 to contain subnet address");
+SYSCTL_INT(_net_inet_igmp, OID_AUTO, sendra, CTLFLAG_RW | CTLFLAG_LOCKED,
+    &igmp_sendra, 0,
+    "Send IP Router Alert option in IGMPv2/v3 messages");
+SYSCTL_INT(_net_inet_igmp, OID_AUTO, sendlocal, CTLFLAG_RW | CTLFLAG_LOCKED,
+    &igmp_sendlocal, 0,
+    "Send IGMP membership reports for 224.0.0.0/24 groups");
+SYSCTL_INT(_net_inet_igmp, OID_AUTO, v1enable, CTLFLAG_RW | CTLFLAG_LOCKED,
+    &igmp_v1enable, 0,
+    "Enable backwards compatibility with IGMPv1");
+SYSCTL_INT(_net_inet_igmp, OID_AUTO, v2enable, CTLFLAG_RW | CTLFLAG_LOCKED,
+    &igmp_v2enable, 0,
+    "Enable backwards compatibility with IGMPv2");
+SYSCTL_INT(_net_inet_igmp, OID_AUTO, legacysupp, CTLFLAG_RW | CTLFLAG_LOCKED,
+    &igmp_legacysupp, 0,
+    "Allow v1/v2 reports to suppress v3 group responses");
+SYSCTL_PROC(_net_inet_igmp, OID_AUTO, default_version,
+  CTLTYPE_INT | CTLFLAG_RW,
+  &igmp_default_version, 0, sysctl_igmp_default_version, "I",
+    "Default version of IGMP to run on each interface");
+SYSCTL_PROC(_net_inet_igmp, OID_AUTO, gsrdelay,
+    CTLTYPE_INT | CTLFLAG_RW,
+    &igmp_gsrdelay.tv_sec, 0, sysctl_igmp_gsr, "I",
+    "Rate limit for IGMPv3 Group-and-Source queries in seconds");
+#ifdef IGMP_DEBUG
+int igmp_debug = 0;
+SYSCTL_INT(_net_inet_igmp, OID_AUTO,
+       debug, CTLFLAG_RW | CTLFLAG_LOCKED, &igmp_debug, 0, "");
+#endif
 
-static struct igmpstat igmpstat;
+SYSCTL_NODE(_net_inet_igmp, OID_AUTO, ifinfo, CTLFLAG_RD | CTLFLAG_LOCKED,
+    sysctl_igmp_ifinfo, "Per-interface IGMPv3 state");
 
-SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RD,
-       &igmpstat, igmpstat, "");
+/* Lock group and attribute for igmp_mtx */
+static lck_attr_t      *igmp_mtx_attr;
+static lck_grp_t       *igmp_mtx_grp;
+static lck_grp_attr_t  *igmp_mtx_grp_attr;
 
+/*
+ * Locking and reference counting:
+ *
+ * igmp_mtx mainly protects igi_head.  In cases where both igmp_mtx and
+ * in_multihead_lock must be held, the former must be acquired first in order
+ * to maintain lock ordering.  It is not a requirement that igmp_mtx be
+ * acquired first before in_multihead_lock, but in case both must be acquired
+ * in succession, the correct lock ordering must be followed.
+ *
+ * Instead of walking the if_multiaddrs list at the interface and returning
+ * the ifma_protospec value of a matching entry, we search the global list
+ * of in_multi records and find it that way; this is done with in_multihead
+ * lock held.  Doing so avoids the race condition issues that many other BSDs
+ * suffer from (therefore in our implementation, ifma_protospec will never be
+ * NULL for as long as the in_multi is valid.)
+ *
+ * The above creates a requirement for the in_multi to stay in in_multihead
+ * list even after the final IGMP leave (in IGMPv3 mode) until no longer needs
+ * be retransmitted (this is not required for IGMPv1/v2.)  In order to handle
+ * this, the request and reference counts of the in_multi are bumped up when
+ * the state changes to IGMP_LEAVING_MEMBER, and later dropped in the timeout
+ * handler.  Each in_multi holds a reference to the underlying igmp_ifinfo.
+ *
+ * Thus, the permitted lock oder is:
+ *
+ *     igmp_mtx, in_multihead_lock, inm_lock, igi_lock
+ *
+ * Any may be taken independently, but if any are held at the same time,
+ * the above lock order must be followed.
+ */
+static decl_lck_mtx_data(, igmp_mtx);
 static int igmp_timers_are_running;
-static uint32_t igmp_all_hosts_group;
-static uint32_t igmp_all_rtrs_group;
-static struct mbuf *router_alert;
-static struct router_info *Head;
 
-static void igmp_sendpkt(struct in_multi *, int, uint32_t);
+#define        IGMP_ADD_DETACHED_INM(_head, _inm) {                            \
+       SLIST_INSERT_HEAD(_head, _inm, inm_dtle);                       \
+}
 
-void
-igmp_init(void)
-{
-       struct ipoption *ra;
+#define        IGMP_REMOVE_DETACHED_INM(_head) {                               \
+       struct in_multi *_inm, *_inm_tmp;                               \
+       SLIST_FOREACH_SAFE(_inm, _head, inm_dtle, _inm_tmp) {           \
+               SLIST_REMOVE(_head, _inm, in_multi, inm_dtle);          \
+               INM_REMREF(_inm);                                       \
+       }                                                               \
+       VERIFY(SLIST_EMPTY(_head));                                     \
+}
 
-       /*
-        * To avoid byte-swapping the same value over and over again.
-        */
-       igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
-       igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP);
+#define        IGI_ZONE_MAX            64              /* maximum elements in zone */
+#define        IGI_ZONE_NAME           "igmp_ifinfo"   /* zone name */
 
-       igmp_timers_are_running = 0;
+static unsigned int igi_size;                  /* size of zone element */
+static struct zone *igi_zone;                  /* zone for igmp_ifinfo */
 
-       /*
-        * Construct a Router Alert option to use in outgoing packets
-        */
-       MGET(router_alert, M_WAIT, MT_DATA);
-       ra = mtod(router_alert, struct ipoption *);
-       ra->ipopt_dst.s_addr = 0;
-       ra->ipopt_list[0] = IPOPT_RA;   /* Router Alert Option */
-       ra->ipopt_list[1] = 0x04;       /* 4 bytes long */
-       ra->ipopt_list[2] = 0x00;
-       ra->ipopt_list[3] = 0x00;
-       router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1];
+/* Store IGMPv3 record count in the module private scratch space */
+#define        vt_nrecs        pkt_mpriv.__mpriv_u.__mpriv32[0].__mpriv32_u.__val16[0]
 
-       Head = (struct router_info *) 0;
+static __inline void
+igmp_save_context(struct mbuf *m, struct ifnet *ifp)
+{
+        m->m_pkthdr.rcvif = ifp;
 }
 
-static struct router_info *
-find_rti(
-       struct ifnet *ifp, int wait)
+static __inline void
+igmp_scrub_context(struct mbuf *m)
 {
-       struct router_info *rti = Head;
-       
-       
-#if IGMP_DEBUG
-       printf("[igmp.c, _find_rti] --> entering \n");
-#endif
-       while (rti) {
-               if (rti->rti_ifp == ifp) {
-#if IGMP_DEBUG
-                       printf("[igmp.c, _find_rti] --> found old entry \n");
-#endif
-                       return rti;
-               }
-               rti = rti->rti_next;
-       }
-       
-       MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, wait);
-       if (rti != NULL)
-       {
-               rti->rti_ifp = ifp;
-               rti->rti_type = IGMP_V2_ROUTER;
-               rti->rti_time = 0;
-               rti->rti_next = Head;
-               Head = rti;
-       }
-#if IGMP_DEBUG
-       if (rti) printf("[igmp.c, _find_rti] --> created an entry \n");
+        m->m_pkthdr.rcvif = NULL;
+}
+
+#ifdef IGMP_DEBUG
+static __inline const char *
+inet_ntop_haddr(in_addr_t haddr, char *buf, socklen_t size)
+{
+       struct in_addr ia;
+
+       ia.s_addr = htonl(haddr);
+       return (inet_ntop(AF_INET, &ia, buf, size));
+}
 #endif
-       return rti;
+
+/*
+ * Restore context from a queued IGMP output chain.
+ * Return saved ifp.
+ */
+static __inline struct ifnet *
+igmp_restore_context(struct mbuf *m)
+{
+        return (m->m_pkthdr.rcvif);
 }
 
-void
-igmp_input(
-       struct mbuf *m,
-       int iphlen)
+/*
+ * Retrieve or set default IGMP version.
+ */
+static int
+sysctl_igmp_default_version SYSCTL_HANDLER_ARGS
 {
-       struct igmp *igmp;
-       struct ip *ip;
-       int igmplen;
-       struct ifnet *ifp = m->m_pkthdr.rcvif;
-       int minlen;
-       struct in_multi *inm;
-       struct in_ifaddr *ia;
-       struct in_multistep step;
-       struct router_info *rti;
-       
-       int timer; /** timer value in the igmp query header **/
+#pragma unused(oidp, arg2)
+       int      error;
+       int      new;
 
-       ++igmpstat.igps_rcv_total;
+       IGMP_LOCK();
 
-       ip = mtod(m, struct ip *);
-       igmplen = ip->ip_len;
+       error = SYSCTL_OUT(req, arg1, sizeof(int));
+       if (error || !req->newptr)
+               goto out_locked;
 
-       /*
-        * Validate lengths
-        */
-       if (igmplen < IGMP_MINLEN) {
-               ++igmpstat.igps_rcv_tooshort;
-               m_freem(m);
-               return;
-       }
-       minlen = iphlen + IGMP_MINLEN;
-       if ((m->m_flags & M_EXT || m->m_len < minlen) &&
-           (m = m_pullup(m, minlen)) == 0) {
-               ++igmpstat.igps_rcv_tooshort;
-               return;
-       }
+       new = igmp_default_version;
 
-       /*
-        * Validate checksum
-        */
-       m->m_data += iphlen;
-       m->m_len -= iphlen;
-       igmp = mtod(m, struct igmp *);
-       if (in_cksum(m, igmplen)) {
-               ++igmpstat.igps_rcv_badsum;
-               m_freem(m);
-               return;
-       }
-       m->m_data -= iphlen;
-       m->m_len += iphlen;
+       error = SYSCTL_IN(req, &new, sizeof(int));
+       if (error)
+               goto out_locked;
 
-       ip = mtod(m, struct ip *);
-       timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
-       if (timer == 0)
-               timer = 1;
-       rti = find_rti(ifp, M_NOWAIT);
-       if (rti == NULL) {
-               m_freem(m);
-               return;
+       if (new < IGMP_VERSION_1 || new > IGMP_VERSION_3) {
+               error = EINVAL;
+               goto out_locked;
        }
 
-       /*
-        * In the IGMPv2 specification, there are 3 states and a flag.
-        *
-        * In Non-Member state, we simply don't have a membership record.
-        * In Delaying Member state, our timer is running (inm->inm_timer)
-        * In Idle Member state, our timer is not running (inm->inm_timer==0)
-        *
-        * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if
-        * we have heard a report from another member, or IGMP_IREPORTEDLAST
-        * if I sent the last report.
-        */
-       switch (igmp->igmp_type) {
+       IGMP_PRINTF(("%s: change igmp_default_version from %d to %d\n",
+           __func__, igmp_default_version, new));
 
-       case IGMP_MEMBERSHIP_QUERY:
-               ++igmpstat.igps_rcv_queries;
+       igmp_default_version = new;
 
-               if (ifp->if_flags & IFF_LOOPBACK)
-                       break;
+out_locked:
+       IGMP_UNLOCK();
+       return (error);
+}
 
-               if (igmp->igmp_code == 0) {
-                       /*
-                        * Old router.  Remember that the querier on this
-                        * interface is old, and set the timer to the
-                        * value in RFC 1112.
-                        */
+/*
+ * Retrieve or set threshold between group-source queries in seconds.
+ *
+ */
+static int
+sysctl_igmp_gsr SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2)
+       int error;
+       int i;
 
-                       rti->rti_type = IGMP_V1_ROUTER;
-                       rti->rti_time = 0;
+       IGMP_LOCK();
 
-                       timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ;
+       i = igmp_gsrdelay.tv_sec;
 
-                       if (ip->ip_dst.s_addr != igmp_all_hosts_group ||
-                           igmp->igmp_group.s_addr != 0) {
-                               ++igmpstat.igps_rcv_badqueries;
-                               m_freem(m);
-                               return;
-                       }
-               } else {
-                       /*
-                        * New router.  Simply do the new validity check.
-                        */
-                       
-                       if (igmp->igmp_group.s_addr != 0 &&
-                           !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
-                               ++igmpstat.igps_rcv_badqueries;
-                               m_freem(m);
-                               return;
-                       }
-               }
+       error = sysctl_handle_int(oidp, &i, 0, req);
+       if (error || !req->newptr)
+               goto out_locked;
 
-               /*
-                * - Start the timers in all of our membership records
-                *   that the query applies to for the interface on
-                *   which the query arrived excl. those that belong
-                *   to the "all-hosts" group (224.0.0.1).
-                * - Restart any timer that is already running but has
-                *   a value longer than the requested timeout.
-                * - Use the value specified in the query message as
-                *   the maximum timeout.
-                */
-               lck_mtx_lock(rnh_lock);
-               IN_FIRST_MULTI(step, inm);
-               while (inm != NULL) {
-                       if (inm->inm_ifp == ifp &&
-                           inm->inm_addr.s_addr != igmp_all_hosts_group &&
-                           (igmp->igmp_group.s_addr == 0 ||
-                            igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) {
-                               if (inm->inm_timer == 0 ||
-                                   inm->inm_timer > timer) {
-                                       inm->inm_timer =
-                                               IGMP_RANDOM_DELAY(timer);
-                                       igmp_timers_are_running = 1;
-                               }
-                       }
-                       IN_NEXT_MULTI(step, inm);
-               }
-               lck_mtx_unlock(rnh_lock);
+       if (i < -1 || i >= 60) {
+               error = EINVAL;
+               goto out_locked;
+       }
 
-               break;
+       igmp_gsrdelay.tv_sec = i;
 
-       case IGMP_V1_MEMBERSHIP_REPORT:
-       case IGMP_V2_MEMBERSHIP_REPORT:
-               /*
-                * For fast leave to work, we have to know that we are the
-                * last person to send a report for this group.  Reports
-                * can potentially get looped back if we are a multicast
-                * router, so discard reports sourced by me.
-                */
-               IFP_TO_IA(ifp, ia);
-               if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) {
-                       ifafree(&ia->ia_ifa);
-                       break;
-               }
+out_locked:
+       IGMP_UNLOCK();
+       return (error);
+}
 
-               ++igmpstat.igps_rcv_reports;
+/*
+ * Expose struct igmp_ifinfo to userland, keyed by ifindex.
+ * For use by ifmcstat(8).
+ *
+ */
+static int
+sysctl_igmp_ifinfo SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp)
+       int                     *name;
+       int                      error;
+       u_int                    namelen;
+       struct ifnet            *ifp;
+       struct igmp_ifinfo      *igi;
+       struct igmp_ifinfo_u    igi_u;
 
-               if (ifp->if_flags & IFF_LOOPBACK) {
-                       if (ia != NULL)
-                               ifafree(&ia->ia_ifa);
-                       break;
-               }
+       name = (int *)arg1;
+       namelen = arg2;
 
-               if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
-                       ++igmpstat.igps_rcv_badreports;
-                       m_freem(m);
-                       if (ia != NULL)
-                               ifafree(&ia->ia_ifa);
-                       return;
-               }
+       if (req->newptr != USER_ADDR_NULL)
+               return (EPERM);
 
-               /*
-                * KLUDGE: if the IP source address of the report has an
-                * unspecified (i.e., zero) subnet number, as is allowed for
-                * a booting host, replace it with the correct subnet number
-                * so that a process-level multicast routing demon can
-                * determine which subnet it arrived from.  This is necessary
-                * to compensate for the lack of any way for a process to
-                * determine the arrival interface of an incoming packet.
-                */
-               if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0)
-                       if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);
+       if (namelen != 1)
+               return (EINVAL);
 
-               /*
-                * If we belong to the group being reported, stop
-                * our timer for that group.
-                */
-               ifnet_lock_shared(ifp);
-               IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm);
-               ifnet_lock_done(ifp);
+       IGMP_LOCK();
 
-               if (inm != NULL) {
-                       inm->inm_timer = 0;
-                       ++igmpstat.igps_rcv_ourreports;
+       if (name[0] <= 0 || name[0] > (u_int)if_index) {
+               error = ENOENT;
+               goto out_locked;
+       }
+
+       error = ENOENT;
+
+       ifnet_head_lock_shared();
+       ifp = ifindex2ifnet[name[0]];
+       ifnet_head_done();
+       if (ifp == NULL)
+               goto out_locked;
 
-                       inm->inm_state = IGMP_OTHERMEMBER;
+       bzero(&igi_u, sizeof (igi_u));
+
+       LIST_FOREACH(igi, &igi_head, igi_link) {
+               IGI_LOCK(igi);
+               if (ifp != igi->igi_ifp) {
+                       IGI_UNLOCK(igi);
+                       continue;
                }
+               igi_u.igi_ifindex = igi->igi_ifp->if_index;
+               igi_u.igi_version = igi->igi_version;
+               igi_u.igi_v1_timer = igi->igi_v1_timer;
+               igi_u.igi_v2_timer = igi->igi_v2_timer;
+               igi_u.igi_v3_timer = igi->igi_v3_timer;
+               igi_u.igi_flags = igi->igi_flags;
+               igi_u.igi_rv = igi->igi_rv;
+               igi_u.igi_qi = igi->igi_qi;
+               igi_u.igi_qri = igi->igi_qri;
+               igi_u.igi_uri = igi->igi_uri;
+               IGI_UNLOCK(igi);
 
-               if (ia != NULL)
-                       ifafree(&ia->ia_ifa);
+               error = SYSCTL_OUT(req, &igi_u, sizeof (igi_u));
                break;
        }
 
-       /*
-        * Pass all valid IGMP packets up to any process(es) listening
-        * on a raw IGMP socket.
-        */
-       rip_input(m, iphlen);
+out_locked:
+       IGMP_UNLOCK();
+       return (error);
 }
 
-int
-igmp_joingroup(struct in_multi *inm)
+/*
+ * Dispatch an entire queue of pending packet chains
+ *
+ * Must not be called with inm_lock held.
+ */
+static void
+igmp_dispatch_queue(struct igmp_ifinfo *igi, struct ifqueue *ifq, int limit,
+    const int loop)
 {
+       struct mbuf *m;
+       struct ip *ip;
 
-       if (inm->inm_addr.s_addr == igmp_all_hosts_group
-           || inm->inm_ifp->if_flags & IFF_LOOPBACK) {
-               inm->inm_timer = 0;
-               inm->inm_state = IGMP_OTHERMEMBER;
-       } else {
-               inm->inm_rti = find_rti(inm->inm_ifp, M_WAITOK);
-               if (inm->inm_rti == NULL) return ENOMEM;
-               igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
-               inm->inm_timer = IGMP_RANDOM_DELAY(
-                                       IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ);
-               inm->inm_state = IGMP_IREPORTEDLAST;
-               igmp_timers_are_running = 1;
+       if (igi != NULL)
+               IGI_LOCK_ASSERT_HELD(igi);
+
+       for (;;) {
+               IF_DEQUEUE(ifq, m);
+               if (m == NULL)
+                       break;
+               IGMP_PRINTF(("%s: dispatch 0x%llx from 0x%llx\n", __func__,
+                   (uint64_t)VM_KERNEL_ADDRPERM(ifq),
+                   (uint64_t)VM_KERNEL_ADDRPERM(m)));
+               ip = mtod(m, struct ip *);
+               if (loop)
+                       m->m_flags |= M_IGMP_LOOP;
+               if (igi != NULL)
+                       IGI_UNLOCK(igi);
+               igmp_sendpkt(m);
+               if (igi != NULL)
+                       IGI_LOCK(igi);
+               if (--limit == 0)
+                       break;
        }
-       return 0;
+
+       if (igi != NULL)
+               IGI_LOCK_ASSERT_HELD(igi);
 }
 
-void
-igmp_leavegroup(struct in_multi *inm)
+/*
+ * Filter outgoing IGMP report state by group.
+ *
+ * Reports are ALWAYS suppressed for ALL-HOSTS (224.0.0.1).
+ * If the net.inet.igmp.sendlocal sysctl is 0, then IGMP reports are
+ * disabled for all groups in the 224.0.0.0/24 link-local scope. However,
+ * this may break certain IGMP snooping switches which rely on the old
+ * report behaviour.
+ *
+ * Return zero if the given group is one for which IGMP reports
+ * should be suppressed, or non-zero if reports should be issued.
+ */
+
+static __inline__
+int igmp_isgroupreported(const struct in_addr addr)
+{
+
+       if (in_allhosts(addr) ||
+           ((!igmp_sendlocal && IN_LOCAL_GROUP(ntohl(addr.s_addr)))))
+               return (0);
+
+       return (1);
+}
+
+/*
+ * Construct a Router Alert option to use in outgoing packets.
+ */
+static struct mbuf *
+igmp_ra_alloc(void)
+{
+       struct mbuf     *m;
+       struct ipoption *p;
+
+       MGET(m, M_WAITOK, MT_DATA);
+       p = mtod(m, struct ipoption *);
+       p->ipopt_dst.s_addr = INADDR_ANY;
+       p->ipopt_list[0] = (char)IPOPT_RA;      /* Router Alert Option */
+       p->ipopt_list[1] = 0x04;        /* 4 bytes long */
+       p->ipopt_list[2] = IPOPT_EOL;   /* End of IP option list */
+       p->ipopt_list[3] = 0x00;        /* pad byte */
+       m->m_len = sizeof(p->ipopt_dst) + p->ipopt_list[1];
+
+       return (m);
+}
+
+/*
+ * Attach IGMP when PF_INET is attached to an interface.
+ */
+struct igmp_ifinfo *
+igmp_domifattach(struct ifnet *ifp, int how)
 {
-       if (inm->inm_state == IGMP_IREPORTEDLAST &&
-           inm->inm_addr.s_addr != igmp_all_hosts_group &&
-           !(inm->inm_ifp->if_flags & IFF_LOOPBACK) &&
-           inm->inm_rti->rti_type != IGMP_V1_ROUTER)
-               igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group);
+       struct igmp_ifinfo *igi;
+
+       IGMP_PRINTF(("%s: called for ifp 0x%llx(%s)\n",
+           __func__, (uint64_t)VM_KERNEL_ADDRPERM(ifp), ifp->if_name));
+
+       igi = igi_alloc(how);
+       if (igi == NULL)
+               return (NULL);
+
+       IGMP_LOCK();
+
+       IGI_LOCK(igi);
+       igi_initvar(igi, ifp, 0);
+       igi->igi_debug |= IFD_ATTACHED;
+       IGI_ADDREF_LOCKED(igi); /* hold a reference for igi_head */
+       IGI_ADDREF_LOCKED(igi); /* hold a reference for caller */
+       IGI_UNLOCK(igi);
+       ifnet_lock_shared(ifp);
+       igmp_initsilent(ifp, igi);
+       ifnet_lock_done(ifp);
+
+       LIST_INSERT_HEAD(&igi_head, igi, igi_link);
+
+       IGMP_UNLOCK();
+
+       IGMP_PRINTF(("%s: allocate igmp_ifinfo for ifp 0x%llx(%s)\n", __func__,
+            (uint64_t)VM_KERNEL_ADDRPERM(ifp), ifp->if_name));
+
+       return (igi);
 }
 
+/*
+ * Attach IGMP when PF_INET is reattached to an interface.  Caller is
+ * expected to have an outstanding reference to the igi.
+ */
 void
-igmp_fasttimo(void)
+igmp_domifreattach(struct igmp_ifinfo *igi)
 {
-       struct in_multi *inm;
-       struct in_multistep step;
+       struct ifnet *ifp;
 
-       /*
-        * Quick check to see if any work needs to be done, in order
-        * to minimize the overhead of fasttimo processing.
-        */
+       IGMP_LOCK();
 
-       if (!igmp_timers_are_running)
-               return;
+       IGI_LOCK(igi);
+       VERIFY(!(igi->igi_debug & IFD_ATTACHED));
+       ifp = igi->igi_ifp;
+       VERIFY(ifp != NULL);
+       igi_initvar(igi, ifp, 1);
+       igi->igi_debug |= IFD_ATTACHED;
+       IGI_ADDREF_LOCKED(igi); /* hold a reference for igi_head */
+       IGI_UNLOCK(igi);
+       ifnet_lock_shared(ifp);
+       igmp_initsilent(ifp, igi);
+       ifnet_lock_done(ifp);
 
-       igmp_timers_are_running = 0;
-       IN_FIRST_MULTI(step, inm);
-       while (inm != NULL) {
-               if (inm->inm_timer == 0) {
-                       /* do nothing */
-               } else if ((--inm->inm_timer == 0) && (inm->inm_rti != NULL)) {
-                       igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
-                       inm->inm_state = IGMP_IREPORTEDLAST;
-               } else {
-                       igmp_timers_are_running = 1;
-               }
-               IN_NEXT_MULTI(step, inm);
-       }
+       LIST_INSERT_HEAD(&igi_head, igi, igi_link);
+
+       IGMP_UNLOCK();
+
+       IGMP_PRINTF(("%s: reattached igmp_ifinfo for ifp 0x%llx(%s)\n",
+           __func__, (uint64_t)VM_KERNEL_ADDRPERM(ifp), ifp->if_name));
 }
 
+/*
+ * Hook for domifdetach.
+ */
 void
-igmp_slowtimo(void)
+igmp_domifdetach(struct ifnet *ifp)
 {
-       struct router_info *rti =  Head;
+       SLIST_HEAD(, in_multi) inm_dthead;
 
-#if IGMP_DEBUG
-       printf("[igmp.c,_slowtimo] -- > entering \n");
-#endif
-       while (rti) {
-           if (rti->rti_type == IGMP_V1_ROUTER) {
-               rti->rti_time++;
-               if (rti->rti_time >= IGMP_AGE_THRESHOLD) {
-                       rti->rti_type = IGMP_V2_ROUTER;
+       SLIST_INIT(&inm_dthead);
+
+       IGMP_PRINTF(("%s: called for ifp 0x%llx(%s%d)\n", __func__,
+           (uint64_t)VM_KERNEL_ADDRPERM(ifp), ifp->if_name, ifp->if_unit));
+
+       IGMP_LOCK();
+       igi_delete(ifp, (struct igmp_inm_relhead *)&inm_dthead);
+       IGMP_UNLOCK();
+
+       /* Now that we're dropped all locks, release detached records */
+       IGMP_REMOVE_DETACHED_INM(&inm_dthead);
+}
+
+/*
+ * Called at interface detach time.  Note that we only flush all deferred
+ * responses and record releases; all remaining inm records and their source
+ * entries related to this interface are left intact, in order to handle
+ * the reattach case.
+ */
+static void
+igi_delete(const struct ifnet *ifp, struct igmp_inm_relhead *inm_dthead)
+{
+       struct igmp_ifinfo *igi, *tigi;
+
+       IGMP_LOCK_ASSERT_HELD();
+
+       LIST_FOREACH_SAFE(igi, &igi_head, igi_link, tigi) {
+               IGI_LOCK(igi);
+               if (igi->igi_ifp == ifp) {
+                       /*
+                        * Free deferred General Query responses.
+                        */
+                       IF_DRAIN(&igi->igi_gq);
+                       IF_DRAIN(&igi->igi_v2q);
+                       igmp_flush_relq(igi, inm_dthead);
+                       VERIFY(SLIST_EMPTY(&igi->igi_relinmhead));
+                       igi->igi_debug &= ~IFD_ATTACHED;
+                       IGI_UNLOCK(igi);
+
+                       LIST_REMOVE(igi, igi_link);
+                       IGI_REMREF(igi); /* release igi_head reference */
+                       return;
                }
-           }
-           rti = rti->rti_next;
+               IGI_UNLOCK(igi);
        }
-#if IGMP_DEBUG 
-       printf("[igmp.c,_slowtimo] -- > exiting \n");
-#endif
+       panic("%s: igmp_ifinfo not found for ifp %p(%s)\n", __func__,
+           ifp, ifp->if_xname);
 }
 
-static struct route igmprt;
+__private_extern__ void
+igmp_initsilent(struct ifnet *ifp, struct igmp_ifinfo *igi)
+{
+       ifnet_lock_assert(ifp, IFNET_LCK_ASSERT_OWNED);
+
+       IGI_LOCK_ASSERT_NOTHELD(igi);
+       IGI_LOCK(igi);
+       if (!(ifp->if_flags & IFF_MULTICAST))
+               igi->igi_flags |= IGIF_SILENT;
+       else
+               igi->igi_flags &= ~IGIF_SILENT;
+       IGI_UNLOCK(igi);
+}
 
 static void
-igmp_sendpkt(struct in_multi *inm, int type, uint32_t addr)
+igi_initvar(struct igmp_ifinfo *igi, struct ifnet *ifp, int reattach)
 {
-        struct mbuf *m;
-        struct igmp *igmp;
-        struct ip *ip;
-        struct ip_moptions imo;
+       IGI_LOCK_ASSERT_HELD(igi);
 
-        MGETHDR(m, M_DONTWAIT, MT_HEADER);     /* MAC-OK */
-        if (m == NULL)
-                return;
+       igi->igi_ifp = ifp;
+       igi->igi_version = igmp_default_version;
+       igi->igi_flags = 0;
+       igi->igi_rv = IGMP_RV_INIT;
+       igi->igi_qi = IGMP_QI_INIT;
+       igi->igi_qri = IGMP_QRI_INIT;
+       igi->igi_uri = IGMP_URI_INIT;
 
-       m->m_pkthdr.rcvif = lo_ifp;
-#if CONFIG_MACF_NET
-       mac_mbuf_label_associate_linklayer(inm->inm_ifp, m);
-#endif
-       m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
-       MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip));
-       m->m_data += sizeof(struct ip);
-        m->m_len = IGMP_MINLEN;
-       m->m_pkthdr.csum_flags = 0;
-       m->m_pkthdr.csum_data = 0;
-        igmp = mtod(m, struct igmp *);
-        igmp->igmp_type   = type;
-        igmp->igmp_code   = 0;
-        igmp->igmp_group  = inm->inm_addr;
-        igmp->igmp_cksum  = 0;
-        igmp->igmp_cksum  = in_cksum(m, IGMP_MINLEN);
-
-        m->m_data -= sizeof(struct ip);
-        m->m_len += sizeof(struct ip);
-        ip = mtod(m, struct ip *);
-        ip->ip_tos        = 0;
-        ip->ip_len        = sizeof(struct ip) + IGMP_MINLEN;
-        ip->ip_off        = 0;
-        ip->ip_p          = IPPROTO_IGMP;
-        ip->ip_src.s_addr = INADDR_ANY;
-        ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr;
-
-        imo.imo_multicast_ifp  = inm->inm_ifp;
-        imo.imo_multicast_ttl  = 1;
-               imo.imo_multicast_vif  = -1;
-#if MROUTING
-        /*
-         * Request loopback of the report if we are acting as a multicast
-         * router, so that the process-level routing demon can hear it.
-         */
-        imo.imo_multicast_loop = (ip_mrouter != NULL);
-#else
-        imo.imo_multicast_loop = 0;
-#endif
+       if (!reattach)
+               SLIST_INIT(&igi->igi_relinmhead);
 
        /*
-        * XXX
-        * Do we have to worry about reentrancy here?  Don't think so.
+        * Responses to general queries are subject to bounds.
         */
-        ip_output(m, router_alert, &igmprt, 0, &imo, NULL);
+       igi->igi_gq.ifq_maxlen =  IGMP_MAX_RESPONSE_PACKETS;
+       igi->igi_v2q.ifq_maxlen = IGMP_MAX_RESPONSE_PACKETS;
+}
+
+static struct igmp_ifinfo *
+igi_alloc(int how)
+{
+       struct igmp_ifinfo *igi;
+
+       igi = (how == M_WAITOK) ? zalloc(igi_zone) : zalloc_noblock(igi_zone);
+       if (igi != NULL) {
+               bzero(igi, igi_size);
+               lck_mtx_init(&igi->igi_lock, igmp_mtx_grp, igmp_mtx_attr);
+               igi->igi_debug |= IFD_ALLOC;
+       }
+       return (igi);
+}
+
+static void
+igi_free(struct igmp_ifinfo *igi)
+{
+       IGI_LOCK(igi);
+       if (igi->igi_debug & IFD_ATTACHED) {
+               panic("%s: attached igi=%p is being freed", __func__, igi);
+               /* NOTREACHED */
+       } else if (igi->igi_ifp != NULL) {
+               panic("%s: ifp not NULL for igi=%p", __func__, igi);
+               /* NOTREACHED */
+       } else if (!(igi->igi_debug & IFD_ALLOC)) {
+               panic("%s: igi %p cannot be freed", __func__, igi);
+               /* NOTREACHED */
+       } else if (igi->igi_refcnt != 0) {
+               panic("%s: non-zero refcnt igi=%p", __func__, igi);
+               /* NOTREACHED */
+       }
+       igi->igi_debug &= ~IFD_ALLOC;
+       IGI_UNLOCK(igi);
+
+       lck_mtx_destroy(&igi->igi_lock, igmp_mtx_grp);
+       zfree(igi_zone, igi);
+}
+
+void
+igi_addref(struct igmp_ifinfo *igi, int locked)
+{
+       if (!locked)
+               IGI_LOCK_SPIN(igi);
+       else
+               IGI_LOCK_ASSERT_HELD(igi);
+
+       if (++igi->igi_refcnt == 0) {
+               panic("%s: igi=%p wraparound refcnt", __func__, igi);
+               /* NOTREACHED */
+       }
+       if (!locked)
+               IGI_UNLOCK(igi);
+}
+
+void
+igi_remref(struct igmp_ifinfo *igi)
+{
+       SLIST_HEAD(, in_multi) inm_dthead;
+       struct ifnet *ifp;
+
+       IGI_LOCK_SPIN(igi);
+
+       if (igi->igi_refcnt == 0) {
+               panic("%s: igi=%p negative refcnt", __func__, igi);
+               /* NOTREACHED */
+       }
 
-        ++igmpstat.igps_snd_reports;
+       --igi->igi_refcnt;
+       if (igi->igi_refcnt > 0) {
+               IGI_UNLOCK(igi);
+               return;
+       }
+
+       ifp = igi->igi_ifp;
+       igi->igi_ifp = NULL;
+       IF_DRAIN(&igi->igi_gq);
+       IF_DRAIN(&igi->igi_v2q);
+       SLIST_INIT(&inm_dthead);
+       igmp_flush_relq(igi, (struct igmp_inm_relhead *)&inm_dthead);
+       VERIFY(SLIST_EMPTY(&igi->igi_relinmhead));
+       IGI_UNLOCK(igi);
+
+       /* Now that we're dropped all locks, release detached records */
+       IGMP_REMOVE_DETACHED_INM(&inm_dthead);
+
+       IGMP_PRINTF(("%s: freeing igmp_ifinfo for ifp 0x%llx(%s)\n",
+           __func__, (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+
+       igi_free(igi);
 }
 
+/*
+ * Process a received IGMPv1 query.
+ * Return non-zero if the message should be dropped.
+ */
+static int
+igmp_input_v1_query(struct ifnet *ifp, const struct ip *ip,
+    const struct igmp *igmp)
+{
+       struct igmp_ifinfo      *igi;
+       struct in_multi         *inm;
+       struct in_multistep     step;
+       struct igmp_tparams     itp = { 0, 0, 0, 0 };
+
+       IGMP_LOCK_ASSERT_NOTHELD();
+
+       /*
+        * IGMPv1 Host Membership Queries SHOULD always be addressed to
+        * 224.0.0.1. They are always treated as General Queries.
+        * igmp_group is always ignored. Do not drop it as a userland
+        * daemon may wish to see it.
+        */
+       if (!in_allhosts(ip->ip_dst) || !in_nullhost(igmp->igmp_group)) {
+               IGMPSTAT_INC(igps_rcv_badqueries);
+               OIGMPSTAT_INC(igps_rcv_badqueries);
+               goto done;
+       }
+       IGMPSTAT_INC(igps_rcv_gen_queries);
+
+       igi = IGMP_IFINFO(ifp);
+       VERIFY(igi != NULL);
+
+       IGI_LOCK(igi);
+       if (igi->igi_flags & IGIF_LOOPBACK) {
+               IGMP_PRINTF(("%s: ignore v1 query on IGIF_LOOPBACK "
+                   "ifp 0x%llx(%s)\n", __func__,
+                   (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+               IGI_UNLOCK(igi);
+               goto done;
+       }
+       /*
+        * Switch to IGMPv1 host compatibility mode.
+        */
+       itp.qpt = igmp_set_version(igi, IGMP_VERSION_1);
+       IGI_UNLOCK(igi);
+
+       IGMP_PRINTF(("%s: process v1 query on ifp 0x%llx(%s)\n", __func__,
+           (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+
+       /*
+        * Start the timers in all of our group records
+        * for the interface on which the query arrived,
+        * except those which are already running.
+        */
+       in_multihead_lock_shared();
+       IN_FIRST_MULTI(step, inm);
+       while (inm != NULL) {
+               INM_LOCK(inm);
+               if (inm->inm_ifp != ifp || inm->inm_timer != 0)
+                       goto next;
+
+               switch (inm->inm_state) {
+               case IGMP_NOT_MEMBER:
+               case IGMP_SILENT_MEMBER:
+                       break;
+               case IGMP_G_QUERY_PENDING_MEMBER:
+               case IGMP_SG_QUERY_PENDING_MEMBER:
+               case IGMP_REPORTING_MEMBER:
+               case IGMP_IDLE_MEMBER:
+               case IGMP_LAZY_MEMBER:
+               case IGMP_SLEEPING_MEMBER:
+               case IGMP_AWAKENING_MEMBER:
+                       inm->inm_state = IGMP_REPORTING_MEMBER;
+                       inm->inm_timer = IGMP_RANDOM_DELAY(IGMP_V1V2_MAX_RI);
+                       itp.cst = 1;
+                       break;
+               case IGMP_LEAVING_MEMBER:
+                       break;
+               }
+next:
+               INM_UNLOCK(inm);
+               IN_NEXT_MULTI(step, inm);
+       }
+       in_multihead_lock_done();
+done:
+       igmp_set_timeout(&itp);
+
+       return (0);
+}
+
+/*
+ * Process a received IGMPv2 general or group-specific query.
+ */
+static int
+igmp_input_v2_query(struct ifnet *ifp, const struct ip *ip,
+    const struct igmp *igmp)
+{
+       struct igmp_ifinfo      *igi;
+       struct in_multi         *inm;
+       int                      is_general_query;
+       uint16_t                 timer;
+       struct igmp_tparams      itp = { 0, 0, 0, 0 };
+
+       IGMP_LOCK_ASSERT_NOTHELD();
+
+       is_general_query = 0;
+
+       /*
+        * Validate address fields upfront.
+        */
+       if (in_nullhost(igmp->igmp_group)) {
+               /*
+                * IGMPv2 General Query.
+                * If this was not sent to the all-hosts group, ignore it.
+                */
+               if (!in_allhosts(ip->ip_dst))
+                       goto done;
+               IGMPSTAT_INC(igps_rcv_gen_queries);
+               is_general_query = 1;
+       } else {
+               /* IGMPv2 Group-Specific Query. */
+               IGMPSTAT_INC(igps_rcv_group_queries);
+       }
+
+       igi = IGMP_IFINFO(ifp);
+       VERIFY(igi != NULL);
+
+       IGI_LOCK(igi);
+       if (igi->igi_flags & IGIF_LOOPBACK) {
+               IGMP_PRINTF(("%s: ignore v2 query on IGIF_LOOPBACK "
+                   "ifp 0x%llx(%s)\n", __func__,
+                   (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+               IGI_UNLOCK(igi);
+               goto done;
+       }
+       /*
+        * Ignore v2 query if in v1 Compatibility Mode.
+        */
+       if (igi->igi_version == IGMP_VERSION_1) {
+               IGI_UNLOCK(igi);
+               goto done;
+       }
+       itp.qpt = igmp_set_version(igi, IGMP_VERSION_2);
+       IGI_UNLOCK(igi);
+
+       timer = igmp->igmp_code / IGMP_TIMER_SCALE;
+       if (timer == 0)
+               timer = 1;
+
+       if (is_general_query) {
+               struct in_multistep step;
+
+               IGMP_PRINTF(("%s: process v2 general query on ifp 0x%llx(%s)\n",
+                   __func__, (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+               /*
+                * For each reporting group joined on this
+                * interface, kick the report timer.
+                */
+               in_multihead_lock_shared();
+               IN_FIRST_MULTI(step, inm);
+               while (inm != NULL) {
+                       INM_LOCK(inm);
+                       if (inm->inm_ifp == ifp)
+                               itp.cst += igmp_v2_update_group(inm, timer);
+                       INM_UNLOCK(inm);
+                       IN_NEXT_MULTI(step, inm);
+               }
+               in_multihead_lock_done();
+       } else {
+               /*
+                * Group-specific IGMPv2 query, we need only
+                * look up the single group to process it.
+                */
+               in_multihead_lock_shared();
+               IN_LOOKUP_MULTI(&igmp->igmp_group, ifp, inm);
+               in_multihead_lock_done();
+               if (inm != NULL) {
+                       INM_LOCK(inm);
+                       IGMP_INET_PRINTF(igmp->igmp_group,
+                           ("process v2 query %s on ifp 0x%llx(%s)\n",
+                           _igmp_inet_buf,
+                           (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+                       itp.cst = igmp_v2_update_group(inm, timer);
+                       INM_UNLOCK(inm);
+                       INM_REMREF(inm); /* from IN_LOOKUP_MULTI */
+               }
+       }
+done:
+       igmp_set_timeout(&itp);
+
+       return (0);
+}
+
+/*
+ * Update the report timer on a group in response to an IGMPv2 query.
+ *
+ * If we are becoming the reporting member for this group, start the timer.
+ * If we already are the reporting member for this group, and timer is
+ * below the threshold, reset it.
+ *
+ * We may be updating the group for the first time since we switched
+ * to IGMPv3. If we are, then we must clear any recorded source lists,
+ * and transition to REPORTING state; the group timer is overloaded
+ * for group and group-source query responses. 
+ *
+ * Unlike IGMPv3, the delay per group should be jittered
+ * to avoid bursts of IGMPv2 reports.
+ */
+static uint32_t
+igmp_v2_update_group(struct in_multi *inm, const int timer)
+{
+
+       IGMP_INET_PRINTF(inm->inm_addr, ("%s: %s/%s timer=%d\n",
+           __func__, _igmp_inet_buf, if_name(inm->inm_ifp),
+           timer));
+
+       INM_LOCK_ASSERT_HELD(inm);
+
+       switch (inm->inm_state) {
+       case IGMP_NOT_MEMBER:
+       case IGMP_SILENT_MEMBER:
+               break;
+       case IGMP_REPORTING_MEMBER:
+               if (inm->inm_timer != 0 &&
+                   inm->inm_timer <= timer) {
+                       IGMP_PRINTF(("%s: REPORTING and timer running, "
+                           "skipping.\n", __func__));
+                       break;
+               }
+               /* FALLTHROUGH */
+       case IGMP_SG_QUERY_PENDING_MEMBER:
+       case IGMP_G_QUERY_PENDING_MEMBER:
+       case IGMP_IDLE_MEMBER:
+       case IGMP_LAZY_MEMBER:
+       case IGMP_AWAKENING_MEMBER:
+               IGMP_PRINTF(("%s: ->REPORTING\n", __func__));
+               inm->inm_state = IGMP_REPORTING_MEMBER;
+               inm->inm_timer = IGMP_RANDOM_DELAY(timer);
+               break;
+       case IGMP_SLEEPING_MEMBER:
+               IGMP_PRINTF(("%s: ->AWAKENING\n", __func__));
+               inm->inm_state = IGMP_AWAKENING_MEMBER;
+               break;
+       case IGMP_LEAVING_MEMBER:
+               break;
+       }
+
+       return (inm->inm_timer);
+}
+
+/*
+ * Process a received IGMPv3 general, group-specific or
+ * group-and-source-specific query.
+ * Assumes m has already been pulled up to the full IGMP message length.
+ * Return 0 if successful, otherwise an appropriate error code is returned.
+ */
+static int
+igmp_input_v3_query(struct ifnet *ifp, const struct ip *ip,
+    /*const*/ struct igmpv3 *igmpv3)
+{
+       struct igmp_ifinfo      *igi;
+       struct in_multi         *inm;
+       int                      is_general_query;
+       uint32_t                 maxresp, nsrc, qqi;
+       uint16_t                 timer;
+       uint8_t                  qrv;
+       struct igmp_tparams      itp = { 0, 0, 0, 0 };
+
+       IGMP_LOCK_ASSERT_NOTHELD();
+
+       is_general_query = 0;
+
+       IGMP_PRINTF(("%s: process v3 query on ifp 0x%llx(%s)\n", __func__,
+           (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+
+       maxresp = igmpv3->igmp_code;    /* in 1/10ths of a second */
+       if (maxresp >= 128) {
+               maxresp = IGMP_MANT(igmpv3->igmp_code) <<
+                         (IGMP_EXP(igmpv3->igmp_code) + 3);
+       }
+
+       /*
+        * Robustness must never be less than 2 for on-wire IGMPv3.
+        * FUTURE: Check if ifp has IGIF_LOOPBACK set, as we will make
+        * an exception for interfaces whose IGMPv3 state changes
+        * are redirected to loopback (e.g. MANET).
+        */
+       qrv = IGMP_QRV(igmpv3->igmp_misc);
+       if (qrv < 2) {
+               IGMP_PRINTF(("%s: clamping qrv %d to %d\n", __func__,
+                   qrv, IGMP_RV_INIT));
+               qrv = IGMP_RV_INIT;
+       }
+
+       qqi = igmpv3->igmp_qqi;
+       if (qqi >= 128) {
+               qqi = IGMP_MANT(igmpv3->igmp_qqi) <<
+                    (IGMP_EXP(igmpv3->igmp_qqi) + 3);
+       }
+
+       timer = maxresp / IGMP_TIMER_SCALE;
+       if (timer == 0)
+               timer = 1;
+
+       nsrc = ntohs(igmpv3->igmp_numsrc);
+
+       /*
+        * Validate address fields and versions upfront before
+        * accepting v3 query.
+        */
+       if (in_nullhost(igmpv3->igmp_group)) {
+               /*
+                * IGMPv3 General Query.
+                *
+                * General Queries SHOULD be directed to 224.0.0.1.
+                * A general query with a source list has undefined
+                * behaviour; discard it.
+                */
+               IGMPSTAT_INC(igps_rcv_gen_queries);
+               if (!in_allhosts(ip->ip_dst) || nsrc > 0) {
+                       IGMPSTAT_INC(igps_rcv_badqueries);
+                       OIGMPSTAT_INC(igps_rcv_badqueries);
+                       goto done;
+               }
+               is_general_query = 1;
+       } else {
+               /* Group or group-source specific query. */
+               if (nsrc == 0)
+                       IGMPSTAT_INC(igps_rcv_group_queries);
+               else
+                       IGMPSTAT_INC(igps_rcv_gsr_queries);
+       }
+
+       igi = IGMP_IFINFO(ifp);
+       VERIFY(igi != NULL);
+
+       IGI_LOCK(igi);
+       if (igi->igi_flags & IGIF_LOOPBACK) {
+               IGMP_PRINTF(("%s: ignore v3 query on IGIF_LOOPBACK "
+                   "ifp 0x%llx(%s)\n", __func__,
+                   (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+               IGI_UNLOCK(igi);
+               goto done;
+       }
+
+       /*
+        * Discard the v3 query if we're in Compatibility Mode.
+        * The RFC is not obviously worded that hosts need to stay in
+        * compatibility mode until the Old Version Querier Present
+        * timer expires.
+        */
+       if (igi->igi_version != IGMP_VERSION_3) {
+               IGMP_PRINTF(("%s: ignore v3 query in v%d mode on "
+                   "ifp 0x%llx(%s)\n", __func__, igi->igi_version,
+                   (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+               IGI_UNLOCK(igi);
+               goto done;
+       }
+
+       itp.qpt = igmp_set_version(igi, IGMP_VERSION_3);
+       igi->igi_rv = qrv;
+       igi->igi_qi = qqi;
+       igi->igi_qri = MAX(timer, IGMP_QRI_MIN);
+
+       IGMP_PRINTF(("%s: qrv %d qi %d qri %d\n", __func__, igi->igi_rv,
+           igi->igi_qi, igi->igi_qri));
+
+       if (is_general_query) {
+               /*
+                * Schedule a current-state report on this ifp for
+                * all groups, possibly containing source lists.
+                * If there is a pending General Query response
+                * scheduled earlier than the selected delay, do
+                * not schedule any other reports.
+                * Otherwise, reset the interface timer.
+                */
+               IGMP_PRINTF(("%s: process v3 general query on ifp 0x%llx(%s)\n",
+                   __func__, (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+               if (igi->igi_v3_timer == 0 || igi->igi_v3_timer >= timer) {
+                       itp.it = igi->igi_v3_timer = IGMP_RANDOM_DELAY(timer);
+               }
+               IGI_UNLOCK(igi);
+       } else {
+               IGI_UNLOCK(igi);
+               /*
+                * Group-source-specific queries are throttled on
+                * a per-group basis to defeat denial-of-service attempts.
+                * Queries for groups we are not a member of on this
+                * link are simply ignored.
+                */
+               in_multihead_lock_shared();
+               IN_LOOKUP_MULTI(&igmpv3->igmp_group, ifp, inm);
+               in_multihead_lock_done();
+               if (inm == NULL)
+                       goto done;
+
+               INM_LOCK(inm);
+               if (nsrc > 0) {
+                       if (!ratecheck(&inm->inm_lastgsrtv,
+                           &igmp_gsrdelay)) {
+                               IGMP_PRINTF(("%s: GS query throttled.\n",
+                                   __func__));
+                               IGMPSTAT_INC(igps_drop_gsr_queries);
+                               INM_UNLOCK(inm);
+                               INM_REMREF(inm); /* from IN_LOOKUP_MULTI */
+                               goto done;
+                       }
+               }
+               IGMP_INET_PRINTF(igmpv3->igmp_group,
+                   ("process v3 %s query on ifp 0x%llx(%s)\n", _igmp_inet_buf,
+                   (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+               /*
+                * If there is a pending General Query response
+                * scheduled sooner than the selected delay, no
+                * further report need be scheduled.
+                * Otherwise, prepare to respond to the
+                * group-specific or group-and-source query.
+                */
+               IGI_LOCK(igi);
+               itp.it = igi->igi_v3_timer;
+               IGI_UNLOCK(igi);
+               if (itp.it == 0 || itp.it >= timer) {
+                       (void) igmp_input_v3_group_query(inm, timer, igmpv3);
+                       itp.cst = inm->inm_timer;
+               }
+               INM_UNLOCK(inm);
+               INM_REMREF(inm); /* from IN_LOOKUP_MULTI */
+       }
+done:
+       if (itp.it > 0) {
+               IGMP_PRINTF(("%s: v3 general query response scheduled in "
+                   "T+%d seconds on ifp 0x%llx(%s)\n", __func__, itp.it,
+                   (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+       }
+       igmp_set_timeout(&itp);
+
+       return (0);
+}
+
+/*
+ * Process a recieved IGMPv3 group-specific or group-and-source-specific
+ * query.
+ * Return <0 if any error occured. Currently this is ignored.
+ */
+static int
+igmp_input_v3_group_query(struct in_multi *inm,
+    int timer, /*const*/ struct igmpv3 *igmpv3)
+{
+       int                      retval;
+       uint16_t                 nsrc;
+
+       INM_LOCK_ASSERT_HELD(inm);
+
+       retval = 0;
+
+       switch (inm->inm_state) {
+       case IGMP_NOT_MEMBER:
+       case IGMP_SILENT_MEMBER:
+       case IGMP_SLEEPING_MEMBER:
+       case IGMP_LAZY_MEMBER:
+       case IGMP_AWAKENING_MEMBER:
+       case IGMP_IDLE_MEMBER:
+       case IGMP_LEAVING_MEMBER:
+               return (retval);
+       case IGMP_REPORTING_MEMBER:
+       case IGMP_G_QUERY_PENDING_MEMBER:
+       case IGMP_SG_QUERY_PENDING_MEMBER:
+               break;
+       }
+
+       nsrc = ntohs(igmpv3->igmp_numsrc);
+
+       /*
+        * Deal with group-specific queries upfront.
+        * If any group query is already pending, purge any recorded
+        * source-list state if it exists, and schedule a query response
+        * for this group-specific query.
+        */
+       if (nsrc == 0) {
+               if (inm->inm_state == IGMP_G_QUERY_PENDING_MEMBER ||
+                   inm->inm_state == IGMP_SG_QUERY_PENDING_MEMBER) {
+                       inm_clear_recorded(inm);
+                       timer = min(inm->inm_timer, timer);
+               }
+               inm->inm_state = IGMP_G_QUERY_PENDING_MEMBER;
+               inm->inm_timer = IGMP_RANDOM_DELAY(timer);
+               return (retval);
+       }
+
+       /*
+        * Deal with the case where a group-and-source-specific query has
+        * been received but a group-specific query is already pending.
+        */
+       if (inm->inm_state == IGMP_G_QUERY_PENDING_MEMBER) {
+               timer = min(inm->inm_timer, timer);
+               inm->inm_timer = IGMP_RANDOM_DELAY(timer);
+               return (retval);
+       }
+
+       /*
+        * Finally, deal with the case where a group-and-source-specific
+        * query has been received, where a response to a previous g-s-r
+        * query exists, or none exists.
+        * In this case, we need to parse the source-list which the Querier
+        * has provided us with and check if we have any source list filter
+        * entries at T1 for these sources. If we do not, there is no need
+        * schedule a report and the query may be dropped.
+        * If we do, we must record them and schedule a current-state
+        * report for those sources.
+        * FIXME: Handling source lists larger than 1 mbuf requires that
+        * we pass the mbuf chain pointer down to this function, and use
+        * m_getptr() to walk the chain.
+        */
+       if (inm->inm_nsrc > 0) {
+               const struct in_addr    *ap;
+               int                      i, nrecorded;
+
+               ap = (const struct in_addr *)(igmpv3 + 1);
+               nrecorded = 0;
+               for (i = 0; i < nsrc; i++, ap++) {
+                       retval = inm_record_source(inm, ap->s_addr);
+                       if (retval < 0)
+                               break;
+                       nrecorded += retval;
+               }
+               if (nrecorded > 0) {
+                       IGMP_PRINTF(("%s: schedule response to SG query\n",
+                           __func__));
+                       inm->inm_state = IGMP_SG_QUERY_PENDING_MEMBER;
+                       inm->inm_timer = IGMP_RANDOM_DELAY(timer);
+               }
+       }
+
+       return (retval);
+}
+
+/*
+ * Process a received IGMPv1 host membership report.
+ *
+ * NOTE: 0.0.0.0 workaround breaks const correctness.
+ */
+static int
+igmp_input_v1_report(struct ifnet *ifp, struct mbuf *m, /*const*/ struct ip *ip,
+    /*const*/ struct igmp *igmp)
+{
+       struct in_ifaddr *ia;
+       struct in_multi *inm;
+
+       IGMPSTAT_INC(igps_rcv_reports);
+       OIGMPSTAT_INC(igps_rcv_reports);
+
+       if ((ifp->if_flags & IFF_LOOPBACK) ||
+           (m->m_pkthdr.pkt_flags & PKTF_LOOP))
+               return (0);
+
+       if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr) ||
+           !in_hosteq(igmp->igmp_group, ip->ip_dst))) {
+               IGMPSTAT_INC(igps_rcv_badreports);
+               OIGMPSTAT_INC(igps_rcv_badreports);
+               return (EINVAL);
+       }
+
+       /*
+        * RFC 3376, Section 4.2.13, 9.2, 9.3:
+        * Booting clients may use the source address 0.0.0.0. Some
+        * IGMP daemons may not know how to use IP_RECVIF to determine
+        * the interface upon which this message was received.
+        * Replace 0.0.0.0 with the subnet address if told to do so.
+        */
+       if (igmp_recvifkludge && in_nullhost(ip->ip_src)) {
+               IFP_TO_IA(ifp, ia);
+               if (ia != NULL) {
+                       IFA_LOCK(&ia->ia_ifa);
+                       ip->ip_src.s_addr = htonl(ia->ia_subnet);
+                       IFA_UNLOCK(&ia->ia_ifa);
+                       IFA_REMREF(&ia->ia_ifa);
+               }
+       }
+
+       IGMP_INET_PRINTF(igmp->igmp_group,
+           ("process v1 report %s on ifp 0x%llx(%s)\n", _igmp_inet_buf,
+           (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+
+       /*
+        * IGMPv1 report suppression.
+        * If we are a member of this group, and our membership should be
+        * reported, stop our group timer and transition to the 'lazy' state.
+        */
+       in_multihead_lock_shared();
+       IN_LOOKUP_MULTI(&igmp->igmp_group, ifp, inm);
+       in_multihead_lock_done();
+       if (inm != NULL) {
+               struct igmp_ifinfo *igi;
+
+               INM_LOCK(inm);
+
+               igi = inm->inm_igi;
+               VERIFY(igi != NULL);
+
+               IGMPSTAT_INC(igps_rcv_ourreports);
+               OIGMPSTAT_INC(igps_rcv_ourreports);
+
+               /*
+                * If we are in IGMPv3 host mode, do not allow the
+                * other host's IGMPv1 report to suppress our reports
+                * unless explicitly configured to do so.
+                */
+               IGI_LOCK(igi);
+               if (igi->igi_version == IGMP_VERSION_3) {
+                       if (igmp_legacysupp)
+                               igmp_v3_suppress_group_record(inm);
+                       IGI_UNLOCK(igi);
+                       INM_UNLOCK(inm);
+                       INM_REMREF(inm); /* from IN_LOOKUP_MULTI */
+                       return (0);
+               }
+
+               INM_LOCK_ASSERT_HELD(inm);
+               inm->inm_timer = 0;
+
+               switch (inm->inm_state) {
+               case IGMP_NOT_MEMBER:
+               case IGMP_SILENT_MEMBER:
+                       break;
+               case IGMP_IDLE_MEMBER:
+               case IGMP_LAZY_MEMBER:
+               case IGMP_AWAKENING_MEMBER:
+                       IGMP_INET_PRINTF(igmp->igmp_group,
+                           ("report suppressed for %s on ifp 0x%llx(%s)\n",
+                           _igmp_inet_buf,
+                           (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+               case IGMP_SLEEPING_MEMBER:
+                       inm->inm_state = IGMP_SLEEPING_MEMBER;
+                       break;
+               case IGMP_REPORTING_MEMBER:
+                       IGMP_INET_PRINTF(igmp->igmp_group,
+                           ("report suppressed for %s on ifp 0x%llx(%s)\n",
+                           _igmp_inet_buf,
+                           (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+                       if (igi->igi_version == IGMP_VERSION_1)
+                               inm->inm_state = IGMP_LAZY_MEMBER;
+                       else if (igi->igi_version == IGMP_VERSION_2)
+                               inm->inm_state = IGMP_SLEEPING_MEMBER;
+                       break;
+               case IGMP_G_QUERY_PENDING_MEMBER:
+               case IGMP_SG_QUERY_PENDING_MEMBER:
+               case IGMP_LEAVING_MEMBER:
+                       break;
+               }
+               IGI_UNLOCK(igi);
+               INM_UNLOCK(inm);
+               INM_REMREF(inm); /* from IN_LOOKUP_MULTI */
+       }
+
+       return (0);
+}
+
+/*
+ * Process a received IGMPv2 host membership report.
+ *
+ * NOTE: 0.0.0.0 workaround breaks const correctness.
+ */
+static int
+igmp_input_v2_report(struct ifnet *ifp, struct mbuf *m, /*const*/ struct ip *ip,
+    /*const*/ struct igmp *igmp)
+{
+       struct in_ifaddr *ia;
+       struct in_multi *inm;
+
+       /*
+        * Make sure we don't hear our own membership report.  Fast
+        * leave requires knowing that we are the only member of a
+        * group.
+        */
+       IFP_TO_IA(ifp, ia);
+       if (ia != NULL) {
+               IFA_LOCK(&ia->ia_ifa);
+               if (in_hosteq(ip->ip_src, IA_SIN(ia)->sin_addr)) {
+                       IFA_UNLOCK(&ia->ia_ifa);
+                       IFA_REMREF(&ia->ia_ifa);
+                       return (0);
+               }
+               IFA_UNLOCK(&ia->ia_ifa);
+       }
+
+       IGMPSTAT_INC(igps_rcv_reports);
+       OIGMPSTAT_INC(igps_rcv_reports);
+
+       if ((ifp->if_flags & IFF_LOOPBACK) ||
+           (m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
+               if (ia != NULL)
+                       IFA_REMREF(&ia->ia_ifa);
+               return (0);
+       }
+
+       if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr)) ||
+           !in_hosteq(igmp->igmp_group, ip->ip_dst)) {
+               if (ia != NULL)
+                       IFA_REMREF(&ia->ia_ifa);
+               IGMPSTAT_INC(igps_rcv_badreports);
+               OIGMPSTAT_INC(igps_rcv_badreports);
+               return (EINVAL);
+       }
+
+       /*
+        * RFC 3376, Section 4.2.13, 9.2, 9.3:
+        * Booting clients may use the source address 0.0.0.0. Some
+        * IGMP daemons may not know how to use IP_RECVIF to determine
+        * the interface upon which this message was received.
+        * Replace 0.0.0.0 with the subnet address if told to do so.
+        */
+       if (igmp_recvifkludge && in_nullhost(ip->ip_src)) {
+               if (ia != NULL) {
+                       IFA_LOCK(&ia->ia_ifa);
+                       ip->ip_src.s_addr = htonl(ia->ia_subnet);
+                       IFA_UNLOCK(&ia->ia_ifa);
+               }
+       }
+       if (ia != NULL)
+               IFA_REMREF(&ia->ia_ifa);
+
+       IGMP_INET_PRINTF(igmp->igmp_group,
+           ("process v2 report %s on ifp 0x%llx(%s)\n", _igmp_inet_buf,
+           (uint64_t)VM_KERNEL_ADDRPERM(ifp), if_name(ifp)));
+
+       /*
+        * IGMPv2 report suppression.
+        * If we are a member of this group, and our membership should be
+        * reported, and our group timer is pending or about to be reset,
+        * stop our group timer by transitioning to the 'lazy' state.
+        */
+       in_multihead_lock_shared();
+       IN_LOOKUP_MULTI(&igmp->igmp_group, ifp, inm);
+       in_multihead_lock_done();
+       if (inm != NULL) {
+               struct igmp_ifinfo *igi;
+
+               INM_LOCK(inm);
+               igi = inm->inm_igi;
+               VERIFY(igi != NULL);
+
+               IGMPSTAT_INC(igps_rcv_ourreports);
+               OIGMPSTAT_INC(igps_rcv_ourreports);
+
+               /*
+                * If we are in IGMPv3 host mode, do not allow the
+                * other host's IGMPv1 report to suppress our reports
+                * unless explicitly configured to do so.
+                */
+               IGI_LOCK(igi);
+               if (igi->igi_version == IGMP_VERSION_3) {
+                       if (igmp_legacysupp)
+                               igmp_v3_suppress_group_record(inm);
+                       IGI_UNLOCK(igi);
+                       INM_UNLOCK(inm);
+                       INM_REMREF(inm);
+                       return (0);
+               }
+
+               inm->inm_timer = 0;
+
+               switch (inm->inm_state) {
+               case IGMP_NOT_MEMBER:
+               case IGMP_SILENT_MEMBER:
+               case IGMP_SLEEPING_MEMBER:
+                       break;
+               case IGMP_REPORTING_MEMBER:
+               case IGMP_IDLE_MEMBER:
+               case IGMP_AWAKENING_MEMBER:
+                       IGMP_INET_PRINTF(igmp->igmp_group,
+                           ("report suppressed for %s on ifp 0x%llx(%s)\n",
+                           _igmp_inet_buf, (uint64_t)VM_KERNEL_ADDRPERM(ifp),
+                           if_name(ifp)));
+               case IGMP_LAZY_MEMBER:
+                       inm->inm_state = IGMP_LAZY_MEMBER;
+                       break;
+               case IGMP_G_QUERY_PENDING_MEMBER:
+               case IGMP_SG_QUERY_PENDING_MEMBER:
+               case IGMP_LEAVING_MEMBER:
+                       break;
+               }
+               IGI_UNLOCK(igi);
+               INM_UNLOCK(inm);
+               INM_REMREF(inm);
+       }
+
+       return (0);
+}
+
+void
+igmp_input(struct mbuf *m, int off)
+{
+       int iphlen;
+       struct ifnet *ifp;
+       struct igmp *igmp;
+       struct ip *ip;
+       int igmplen;
+       int minlen;
+       int queryver;
+
+       IGMP_PRINTF(("%s: called w/mbuf (0x%llx,%d)\n", __func__,
+           (uint64_t)VM_KERNEL_ADDRPERM(m), off));
+
+       ifp = m->m_pkthdr.rcvif;
+
+       IGMPSTAT_INC(igps_rcv_total);
+       OIGMPSTAT_INC(igps_rcv_total);
+
+       /* Expect 32-bit aligned data pointer on strict-align platforms */
+       MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m);
+
+       ip = mtod(m, struct ip *);
+       iphlen = off;
+
+       /* By now, ip_len no longer contains the length of IP header */
+       igmplen = ip->ip_len;
+
+       /*
+        * Validate lengths.
+        */
+       if (igmplen < IGMP_MINLEN) {
+               IGMPSTAT_INC(igps_rcv_tooshort);
+               OIGMPSTAT_INC(igps_rcv_tooshort);
+               m_freem(m);
+               return;
+       }
+
+       /*
+        * Always pullup to the minimum size for v1/v2 or v3
+        * to amortize calls to m_pulldown().
+        */
+       if (igmplen >= IGMP_V3_QUERY_MINLEN)
+               minlen = IGMP_V3_QUERY_MINLEN;
+       else
+               minlen = IGMP_MINLEN;
+
+       /* A bit more expensive than M_STRUCT_GET, but ensures alignment */
+       M_STRUCT_GET0(igmp, struct igmp *, m, off, minlen);
+       if (igmp == NULL) {
+               IGMPSTAT_INC(igps_rcv_tooshort);
+               OIGMPSTAT_INC(igps_rcv_tooshort);
+               return;
+       }
+       /* N.B.: we assume the packet was correctly aligned in ip_input. */
+
+       /*
+        * Validate checksum.
+        */
+       m->m_data += iphlen;
+       m->m_len -= iphlen;
+       if (in_cksum(m, igmplen)) {
+               IGMPSTAT_INC(igps_rcv_badsum);
+               OIGMPSTAT_INC(igps_rcv_badsum);
+               m_freem(m);
+               return;
+       }
+       m->m_data -= iphlen;
+       m->m_len += iphlen;
+
+       /*
+        * IGMP control traffic is link-scope, and must have a TTL of 1.
+        * DVMRP traffic (e.g. mrinfo, mtrace) is an exception;
+        * probe packets may come from beyond the LAN.
+        */
+       if (igmp->igmp_type != IGMP_DVMRP && ip->ip_ttl != 1) {
+               IGMPSTAT_INC(igps_rcv_badttl);
+               m_freem(m);
+               return;
+       }
+
+       switch (igmp->igmp_type) {
+       case IGMP_HOST_MEMBERSHIP_QUERY:
+               if (igmplen == IGMP_MINLEN) {
+                       if (igmp->igmp_code == 0)
+                               queryver = IGMP_VERSION_1;
+                       else
+                               queryver = IGMP_VERSION_2;
+               } else if (igmplen >= IGMP_V3_QUERY_MINLEN) {
+                       queryver = IGMP_VERSION_3;
+               } else {
+                       IGMPSTAT_INC(igps_rcv_tooshort);
+                       OIGMPSTAT_INC(igps_rcv_tooshort);
+                       m_freem(m);
+                       return;
+               }
+
+               OIGMPSTAT_INC(igps_rcv_queries);
+
+               switch (queryver) {
+               case IGMP_VERSION_1:
+                       IGMPSTAT_INC(igps_rcv_v1v2_queries);
+                       if (!igmp_v1enable)
+                               break;
+                       if (igmp_input_v1_query(ifp, ip, igmp) != 0) {
+                               m_freem(m);
+                               return;
+                       }
+                       break;
+
+               case IGMP_VERSION_2:
+                       IGMPSTAT_INC(igps_rcv_v1v2_queries);
+                       if (!igmp_v2enable)
+                               break;
+                       if (igmp_input_v2_query(ifp, ip, igmp) != 0) {
+                               m_freem(m);
+                               return;
+                       }
+                       break;
+
+               case IGMP_VERSION_3: {
+                               struct igmpv3 *igmpv3;
+                               uint16_t igmpv3len;
+                               uint16_t srclen;
+                               int nsrc;
+
+                               IGMPSTAT_INC(igps_rcv_v3_queries);
+                               igmpv3 = (struct igmpv3 *)igmp;
+                               /*
+                                * Validate length based on source count.
+                                */
+                               nsrc = ntohs(igmpv3->igmp_numsrc);
+                               /*
+                                * The max vaue of nsrc is limited by the
+                                * MTU of the network on which the datagram
+                                * is received
+                                */
+                               if (nsrc < 0 || nsrc > IGMP_V3_QUERY_MAX_SRCS) {
+                                       IGMPSTAT_INC(igps_rcv_tooshort);
+                                       OIGMPSTAT_INC(igps_rcv_tooshort);
+                                       m_freem(m);
+                                       return;
+                               }
+                               srclen = sizeof(struct in_addr) * nsrc;
+                               if (igmplen < (IGMP_V3_QUERY_MINLEN + srclen)) {
+                                       IGMPSTAT_INC(igps_rcv_tooshort);
+                                       OIGMPSTAT_INC(igps_rcv_tooshort);
+                                       m_freem(m);
+                                       return;
+                               }
+                               igmpv3len = IGMP_V3_QUERY_MINLEN + srclen;
+                               /*
+                                * A bit more expensive than M_STRUCT_GET,
+                                * but ensures alignment.
+                                */
+                               M_STRUCT_GET0(igmpv3, struct igmpv3 *, m,
+                                   off, igmpv3len);
+                               if (igmpv3 == NULL) {
+                                       IGMPSTAT_INC(igps_rcv_tooshort);
+                                       OIGMPSTAT_INC(igps_rcv_tooshort);
+                                       return;
+                               }
+                               /* 
+                                * N.B.: we assume the packet was correctly
+                                * aligned in ip_input.
+                                */
+                               if (igmp_input_v3_query(ifp, ip, igmpv3) != 0) {
+                                       m_freem(m);
+                                       return;
+                               }
+                       }
+                       break;
+               }
+               break;
+
+       case IGMP_v1_HOST_MEMBERSHIP_REPORT:
+               if (!igmp_v1enable)
+                       break;
+               if (igmp_input_v1_report(ifp, m, ip, igmp) != 0) {
+                       m_freem(m);
+                       return;
+               }
+               break;
+
+       case IGMP_v2_HOST_MEMBERSHIP_REPORT:
+               if (!igmp_v2enable)
+                       break;
+               if (!ip_checkrouteralert(m))
+                       IGMPSTAT_INC(igps_rcv_nora);
+               if (igmp_input_v2_report(ifp, m, ip, igmp) != 0) {
+                       m_freem(m);
+                       return;
+               }
+               break;
+
+       case IGMP_v3_HOST_MEMBERSHIP_REPORT:
+               /*
+                * Hosts do not need to process IGMPv3 membership reports,
+                * as report suppression is no longer required.
+                */
+               if (!ip_checkrouteralert(m))
+                       IGMPSTAT_INC(igps_rcv_nora);
+               break;
+
+       default:
+               break;
+       }
+
+       IGMP_LOCK_ASSERT_NOTHELD();
+       /*
+        * Pass all valid IGMP packets up to any process(es) listening on a
+        * raw IGMP socket.
+        */
+       rip_input(m, off);
+}
+
+/*
+ * Schedule IGMP timer based on various parameters; caller must ensure that
+ * lock ordering is maintained as this routine acquires IGMP global lock.
+ */
+void
+igmp_set_timeout(struct igmp_tparams *itp)
+{
+       IGMP_LOCK_ASSERT_NOTHELD();
+       VERIFY(itp != NULL);
+
+       if (itp->qpt != 0 || itp->it != 0 || itp->cst != 0 || itp->sct != 0) {
+               IGMP_LOCK();
+               if (itp->qpt != 0)
+                       querier_present_timers_running = 1;
+               if (itp->it != 0)
+                       interface_timers_running = 1;
+               if (itp->cst != 0)
+                       current_state_timers_running = 1;
+               if (itp->sct != 0)
+                       state_change_timers_running = 1;
+               igmp_sched_timeout();
+               IGMP_UNLOCK();
+       }
+}
+
+/*
+ * IGMP timer handler (per 1 second).
+ */
+static void
+igmp_timeout(void *arg)
+{
+#pragma unused(arg)
+       struct ifqueue           scq;   /* State-change packets */
+       struct ifqueue           qrq;   /* Query response packets */
+       struct ifnet            *ifp;
+       struct igmp_ifinfo      *igi;
+       struct in_multi         *inm;
+       int                      loop = 0, uri_sec = 0;
+       SLIST_HEAD(, in_multi)  inm_dthead;
+
+       SLIST_INIT(&inm_dthead);
+
+       /*
+        * Update coarse-grained networking timestamp (in sec.); the idea
+        * is to piggy-back on the timeout callout to update the counter
+        * returnable via net_uptime().
+        */
+       net_update_uptime();
+
+       IGMP_LOCK();
+
+       IGMP_PRINTF(("%s: qpt %d, it %d, cst %d, sct %d\n", __func__,
+           querier_present_timers_running, interface_timers_running,
+           current_state_timers_running, state_change_timers_running));
+
+       /*
+        * IGMPv1/v2 querier present timer processing.
+        */
+       if (querier_present_timers_running) {
+               querier_present_timers_running = 0;
+               LIST_FOREACH(igi, &igi_head, igi_link) {
+                       IGI_LOCK(igi);
+                       igmp_v1v2_process_querier_timers(igi);
+                       if (igi->igi_v1_timer > 0 || igi->igi_v2_timer > 0)
+                               querier_present_timers_running = 1;
+                       IGI_UNLOCK(igi);
+               }
+       }
+
+       /*
+        * IGMPv3 General Query response timer processing.
+        */
+       if (interface_timers_running) {
+               IGMP_PRINTF(("%s: interface timers running\n", __func__));
+               interface_timers_running = 0;
+               LIST_FOREACH(igi, &igi_head, igi_link) {
+                       IGI_LOCK(igi);
+                       if (igi->igi_version != IGMP_VERSION_3) {
+                               IGI_UNLOCK(igi);
+                               continue;
+                       }
+                       if (igi->igi_v3_timer == 0) {
+                               /* Do nothing. */
+                       } else if (--igi->igi_v3_timer == 0) {
+                               if (igmp_v3_dispatch_general_query(igi) > 0)
+                                       interface_timers_running = 1;
+                       } else {
+                               interface_timers_running = 1;
+                       }
+                       IGI_UNLOCK(igi);
+               }
+       }
+
+       if (!current_state_timers_running &&
+           !state_change_timers_running)
+               goto out_locked;
+
+       current_state_timers_running = 0;
+       state_change_timers_running = 0;
+
+       memset(&qrq, 0, sizeof(struct ifqueue));
+       qrq.ifq_maxlen = IGMP_MAX_G_GS_PACKETS;
+
+       memset(&scq, 0, sizeof(struct ifqueue));
+       scq.ifq_maxlen =  IGMP_MAX_STATE_CHANGE_PACKETS;
+
+       IGMP_PRINTF(("%s: state change timers running\n", __func__));
+
+       /*
+        * IGMPv1/v2/v3 host report and state-change timer processing.
+        * Note: Processing a v3 group timer may remove a node.
+        */
+       LIST_FOREACH(igi, &igi_head, igi_link) {
+               struct in_multistep step;
+
+               IGI_LOCK(igi);
+               ifp = igi->igi_ifp;
+               loop = (igi->igi_flags & IGIF_LOOPBACK) ? 1 : 0;
+               uri_sec = IGMP_RANDOM_DELAY(igi->igi_uri);
+               IGI_UNLOCK(igi);
+
+               in_multihead_lock_shared();
+               IN_FIRST_MULTI(step, inm);
+               while (inm != NULL) {
+                       INM_LOCK(inm);
+                       if (inm->inm_ifp != ifp)
+                               goto next;
+
+                       IGI_LOCK(igi);
+                       switch (igi->igi_version) {
+                               case IGMP_VERSION_1:
+                               case IGMP_VERSION_2:
+                                       igmp_v1v2_process_group_timer(inm,
+                                           igi->igi_version);
+                                       break;
+                               case IGMP_VERSION_3:
+                                       igmp_v3_process_group_timers(igi, &qrq,
+                                           &scq, inm, uri_sec);
+                                       break;
+                       }
+                       IGI_UNLOCK(igi);
+next:
+                       INM_UNLOCK(inm);
+                       IN_NEXT_MULTI(step, inm);
+               }
+               in_multihead_lock_done();
+
+               IGI_LOCK(igi);
+               if (igi->igi_version == IGMP_VERSION_1 ||
+                   igi->igi_version == IGMP_VERSION_2) {
+                       igmp_dispatch_queue(igi, &igi->igi_v2q, 0, loop);
+               } else if (igi->igi_version == IGMP_VERSION_3) {
+                       IGI_UNLOCK(igi);
+                       igmp_dispatch_queue(NULL, &qrq, 0, loop);
+                       igmp_dispatch_queue(NULL, &scq, 0, loop);
+                       VERIFY(qrq.ifq_len == 0);
+                       VERIFY(scq.ifq_len == 0);
+                       IGI_LOCK(igi);
+               }
+               /*
+                * In case there are still any pending membership reports
+                * which didn't get drained at version change time.
+                */
+               IF_DRAIN(&igi->igi_v2q);
+               /*
+                * Release all deferred inm records, and drain any locally
+                * enqueued packets; do it even if the current IGMP version
+                * for the link is no longer IGMPv3, in order to handle the
+                * version change case.
+                */
+               igmp_flush_relq(igi, (struct igmp_inm_relhead *)&inm_dthead);
+               VERIFY(SLIST_EMPTY(&igi->igi_relinmhead));
+               IGI_UNLOCK(igi);
+
+               IF_DRAIN(&qrq);
+               IF_DRAIN(&scq);
+       }
+
+out_locked:
+       /* re-arm the timer if there's work to do */
+       igmp_timeout_run = 0;
+       igmp_sched_timeout();
+       IGMP_UNLOCK();
+
+       /* Now that we're dropped all locks, release detached records */
+       IGMP_REMOVE_DETACHED_INM(&inm_dthead);
+}
+
+static void
+igmp_sched_timeout(void)
+{
+       IGMP_LOCK_ASSERT_HELD();
+
+       if (!igmp_timeout_run &&
+           (querier_present_timers_running || current_state_timers_running ||
+           interface_timers_running || state_change_timers_running)) {
+               igmp_timeout_run = 1;
+               timeout(igmp_timeout, NULL, hz);
+       }
+}
+
+/*
+ * Free the in_multi reference(s) for this IGMP lifecycle.
+ *
+ * Caller must be holding igi_lock.
+ */
+static void
+igmp_flush_relq(struct igmp_ifinfo *igi, struct igmp_inm_relhead *inm_dthead)
+{
+       struct in_multi *inm;
+
+again:
+       IGI_LOCK_ASSERT_HELD(igi);
+       inm = SLIST_FIRST(&igi->igi_relinmhead);
+       if (inm != NULL) {
+               int lastref;
+
+               SLIST_REMOVE_HEAD(&igi->igi_relinmhead, inm_nrele);
+               IGI_UNLOCK(igi);
+
+               in_multihead_lock_exclusive();
+               INM_LOCK(inm);
+               VERIFY(inm->inm_nrelecnt != 0);
+               inm->inm_nrelecnt--;
+               lastref = in_multi_detach(inm);
+               VERIFY(!lastref || (!(inm->inm_debug & IFD_ATTACHED) &&
+                   inm->inm_reqcnt == 0));
+               INM_UNLOCK(inm);
+               in_multihead_lock_done();
+               /* from igi_relinmhead */
+               INM_REMREF(inm);
+               /* from in_multihead list */
+               if (lastref) {
+                       /*
+                        * Defer releasing our final reference, as we
+                        * are holding the IGMP lock at this point, and
+                        * we could end up with locking issues later on
+                        * (while issuing SIOCDELMULTI) when this is the
+                        * final reference count.  Let the caller do it
+                        * when it is safe.
+                        */
+                       IGMP_ADD_DETACHED_INM(inm_dthead, inm);
+               }
+               IGI_LOCK(igi);
+               goto again;
+       }
+}
+
+/*
+ * Update host report group timer for IGMPv1/v2.
+ * Will update the global pending timer flags.
+ */
+static void
+igmp_v1v2_process_group_timer(struct in_multi *inm, const int igmp_version)
+{
+       int report_timer_expired;
+
+       IGMP_LOCK_ASSERT_HELD();
+       INM_LOCK_ASSERT_HELD(inm);
+       IGI_LOCK_ASSERT_HELD(inm->inm_igi);
+
+       if (inm->inm_timer == 0) {
+               report_timer_expired = 0;
+       } else if (--inm->inm_timer == 0) {
+               report_timer_expired = 1;
+       } else {
+               current_state_timers_running = 1;
+               /* caller will schedule timer */
+               return;
+       }
+
+       switch (inm->inm_state) {
+       case IGMP_NOT_MEMBER:
+       case IGMP_SILENT_MEMBER:
+       case IGMP_IDLE_MEMBER:
+       case IGMP_LAZY_MEMBER:
+       case IGMP_SLEEPING_MEMBER:
+       case IGMP_AWAKENING_MEMBER:
+               break;
+       case IGMP_REPORTING_MEMBER:
+               if (report_timer_expired) {
+                       inm->inm_state = IGMP_IDLE_MEMBER;
+                       (void) igmp_v1v2_queue_report(inm,
+                           (igmp_version == IGMP_VERSION_2) ?
+                            IGMP_v2_HOST_MEMBERSHIP_REPORT :
+                            IGMP_v1_HOST_MEMBERSHIP_REPORT);
+                       INM_LOCK_ASSERT_HELD(inm);
+                       IGI_LOCK_ASSERT_HELD(inm->inm_igi);
+               }
+               break;
+       case IGMP_G_QUERY_PENDING_MEMBER:
+       case IGMP_SG_QUERY_PENDING_MEMBER:
+       case IGMP_LEAVING_MEMBER:
+               break;
+       }
+}
+
+/*
+ * Update a group's timers for IGMPv3.
+ * Will update the global pending timer flags.
+ * Note: Unlocked read from igi.
+ */
+static void
+igmp_v3_process_group_timers(struct igmp_ifinfo *igi,
+    struct ifqueue *qrq, struct ifqueue *scq,
+    struct in_multi *inm, const int uri_sec)
+{
+       int query_response_timer_expired;
+       int state_change_retransmit_timer_expired;
+
+       IGMP_LOCK_ASSERT_HELD();
+       INM_LOCK_ASSERT_HELD(inm);
+       IGI_LOCK_ASSERT_HELD(igi);
+       VERIFY(igi == inm->inm_igi);
+
+       query_response_timer_expired = 0;
+       state_change_retransmit_timer_expired = 0;
+
+       /*
+        * During a transition from v1/v2 compatibility mode back to v3,
+        * a group record in REPORTING state may still have its group
+        * timer active. This is a no-op in this function; it is easier
+        * to deal with it here than to complicate the timeout path.
+        */
+       if (inm->inm_timer == 0) {
+               query_response_timer_expired = 0;
+       } else if (--inm->inm_timer == 0) {
+               query_response_timer_expired = 1;
+       } else {
+               current_state_timers_running = 1;
+               /* caller will schedule timer */
+       }
+
+       if (inm->inm_sctimer == 0) {
+               state_change_retransmit_timer_expired = 0;
+       } else if (--inm->inm_sctimer == 0) {
+               state_change_retransmit_timer_expired = 1;
+       } else {
+               state_change_timers_running = 1;
+               /* caller will schedule timer */
+       }
+
+       /* We are in timer callback, so be quick about it. */
+       if (!state_change_retransmit_timer_expired &&
+           !query_response_timer_expired)
+               return;
+
+       switch (inm->inm_state) {
+       case IGMP_NOT_MEMBER:
+       case IGMP_SILENT_MEMBER:
+       case IGMP_SLEEPING_MEMBER:
+       case IGMP_LAZY_MEMBER:
+       case IGMP_AWAKENING_MEMBER:
+       case IGMP_IDLE_MEMBER:
+               break;
+       case IGMP_G_QUERY_PENDING_MEMBER:
+       case IGMP_SG_QUERY_PENDING_MEMBER:
+               /*
+                * Respond to a previously pending Group-Specific
+                * or Group-and-Source-Specific query by enqueueing
+                * the appropriate Current-State report for
+                * immediate transmission.
+                */
+               if (query_response_timer_expired) {
+                       int retval;
+
+                       retval = igmp_v3_enqueue_group_record(qrq, inm, 0, 1,
+                           (inm->inm_state == IGMP_SG_QUERY_PENDING_MEMBER));
+                       IGMP_PRINTF(("%s: enqueue record = %d\n",
+                           __func__, retval));
+                       inm->inm_state = IGMP_REPORTING_MEMBER;
+                       /* XXX Clear recorded sources for next time. */
+                       inm_clear_recorded(inm);
+               }
+               /* FALLTHROUGH */
+       case IGMP_REPORTING_MEMBER:
+       case IGMP_LEAVING_MEMBER:
+               if (state_change_retransmit_timer_expired) {
+                       /*
+                        * State-change retransmission timer fired.
+                        * If there are any further pending retransmissions,
+                        * set the global pending state-change flag, and
+                        * reset the timer.
+                        */
+                       if (--inm->inm_scrv > 0) {
+                               inm->inm_sctimer = uri_sec;
+                               state_change_timers_running = 1;
+                               /* caller will schedule timer */
+                       }
+                       /*
+                        * Retransmit the previously computed state-change
+                        * report. If there are no further pending
+                        * retransmissions, the mbuf queue will be consumed.
+                        * Update T0 state to T1 as we have now sent
+                        * a state-change.
+                        */
+                       (void) igmp_v3_merge_state_changes(inm, scq);
+
+                       inm_commit(inm);
+                       IGMP_INET_PRINTF(inm->inm_addr,
+                           ("%s: T1 -> T0 for %s/%s\n", __func__,
+                           _igmp_inet_buf, if_name(inm->inm_ifp)));
+
+                       /*
+                        * If we are leaving the group for good, make sure
+                        * we release IGMP's reference to it.
+                        * This release must be deferred using a SLIST,
+                        * as we are called from a loop which traverses
+                        * the in_multihead list.
+                        */
+                       if (inm->inm_state == IGMP_LEAVING_MEMBER &&
+                           inm->inm_scrv == 0) {
+                               inm->inm_state = IGMP_NOT_MEMBER;
+                               /*
+                                * A reference has already been held in
+                                * igmp_final_leave() for this inm, so
+                                * no need to hold another one.  We also
+                                * bumped up its request count then, so
+                                * that it stays in in_multihead.  Both
+                                * of them will be released when it is
+                                * dequeued later on.
+                                */
+                               VERIFY(inm->inm_nrelecnt != 0);
+                               SLIST_INSERT_HEAD(&igi->igi_relinmhead,
+                                   inm, inm_nrele);
+                       }
+               }
+               break;
+       }
+}
+
+/*
+ * Suppress a group's pending response to a group or source/group query.
+ *
+ * Do NOT suppress state changes. This leads to IGMPv3 inconsistency.
+ * Do NOT update ST1/ST0 as this operation merely suppresses
+ * the currently pending group record.
+ * Do NOT suppress the response to a general query. It is possible but
+ * it would require adding another state or flag.
+ */
+static void
+igmp_v3_suppress_group_record(struct in_multi *inm)
+{
+
+       INM_LOCK_ASSERT_HELD(inm);
+       IGI_LOCK_ASSERT_HELD(inm->inm_igi);
+
+       VERIFY(inm->inm_igi->igi_version == IGMP_VERSION_3);
+
+       if (inm->inm_state != IGMP_G_QUERY_PENDING_MEMBER ||
+           inm->inm_state != IGMP_SG_QUERY_PENDING_MEMBER)
+               return;
+
+       if (inm->inm_state == IGMP_SG_QUERY_PENDING_MEMBER)
+               inm_clear_recorded(inm);
+
+       inm->inm_timer = 0;
+       inm->inm_state = IGMP_REPORTING_MEMBER;
+}
+
+/*
+ * Switch to a different IGMP version on the given interface,
+ * as per Section 7.2.1.
+ */
+static uint32_t
+igmp_set_version(struct igmp_ifinfo *igi, const int igmp_version)
+{
+       int old_version_timer;
+
+       IGI_LOCK_ASSERT_HELD(igi);
+
+       IGMP_PRINTF(("%s: switching to v%d on ifp 0x%llx(%s)\n", __func__,
+           igmp_version, (uint64_t)VM_KERNEL_ADDRPERM(igi->igi_ifp),
+           if_name(igi->igi_ifp)));
+
+       if (igmp_version == IGMP_VERSION_1 || igmp_version == IGMP_VERSION_2) {
+               /*
+                * Compute the "Older Version Querier Present" timer as per
+                * Section 8.12, in seconds.
+                */
+               old_version_timer = igi->igi_rv * igi->igi_qi + igi->igi_qri;
+
+               if (igmp_version == IGMP_VERSION_1) {
+                       igi->igi_v1_timer = old_version_timer;
+                       igi->igi_v2_timer = 0;
+               } else if (igmp_version == IGMP_VERSION_2) {
+                       igi->igi_v1_timer = 0;
+                       igi->igi_v2_timer = old_version_timer;
+               }
+       }
+
+       if (igi->igi_v1_timer == 0 && igi->igi_v2_timer > 0) {
+               if (igi->igi_version != IGMP_VERSION_2) {
+                       igi->igi_version = IGMP_VERSION_2;
+                       igmp_v3_cancel_link_timers(igi);
+               }
+       } else if (igi->igi_v1_timer > 0) {
+               if (igi->igi_version != IGMP_VERSION_1) {
+                       igi->igi_version = IGMP_VERSION_1;
+                       igmp_v3_cancel_link_timers(igi);
+               }
+       }
+
+       IGI_LOCK_ASSERT_HELD(igi);
+
+       return (MAX(igi->igi_v1_timer, igi->igi_v2_timer));
+}
+
+/*
+ * Cancel pending IGMPv3 timers for the given link and all groups
+ * joined on it; state-change, general-query, and group-query timers.
+ *
+ * Only ever called on a transition from v3 to Compatibility mode. Kill
+ * the timers stone dead (this may be expensive for large N groups), they
+ * will be restarted if Compatibility Mode deems that they must be due to
+ * query processing.
+ */
+static void
+igmp_v3_cancel_link_timers(struct igmp_ifinfo *igi)
+{
+       struct ifnet            *ifp;
+       struct in_multi         *inm;
+       struct in_multistep     step;
+
+       IGI_LOCK_ASSERT_HELD(igi);
+
+       IGMP_PRINTF(("%s: cancel v3 timers on ifp 0x%llx(%s)\n", __func__,
+           (uint64_t)VM_KERNEL_ADDRPERM(igi->igi_ifp), if_name(igi->igi_ifp)));
+
+       /*
+        * Stop the v3 General Query Response on this link stone dead.
+        * If timer is woken up due to interface_timers_running,
+        * the flag will be cleared if there are no pending link timers.
+        */
+       igi->igi_v3_timer = 0;
+
+       /*
+        * Now clear the current-state and state-change report timers
+        * for all memberships scoped to this link.
+        */
+       ifp = igi->igi_ifp;
+       IGI_UNLOCK(igi);
+
+       in_multihead_lock_shared();
+       IN_FIRST_MULTI(step, inm);
+       while (inm != NULL) {
+               INM_LOCK(inm);
+               if (inm->inm_ifp != ifp)
+                       goto next;
+
+               switch (inm->inm_state) {
+               case IGMP_NOT_MEMBER:
+               case IGMP_SILENT_MEMBER:
+               case IGMP_IDLE_MEMBER:
+               case IGMP_LAZY_MEMBER:
+               case IGMP_SLEEPING_MEMBER:
+               case IGMP_AWAKENING_MEMBER:
+                       /*
+                        * These states are either not relevant in v3 mode,
+                        * or are unreported. Do nothing.
+                        */
+                       break;
+               case IGMP_LEAVING_MEMBER:
+                       /*
+                        * If we are leaving the group and switching to
+                        * compatibility mode, we need to release the final
+                        * reference held for issuing the INCLUDE {}, and
+                        * transition to REPORTING to ensure the host leave
+                        * message is sent upstream to the old querier --
+                        * transition to NOT would lose the leave and race.
+                        * During igmp_final_leave(), we bumped up both the
+                        * request and reference counts.  Since we cannot
+                        * call in_multi_detach() here, defer this task to
+                        * the timer routine.
+                        */
+                       VERIFY(inm->inm_nrelecnt != 0);
+                       IGI_LOCK(igi);
+                       SLIST_INSERT_HEAD(&igi->igi_relinmhead, inm, inm_nrele);
+                       IGI_UNLOCK(igi);
+                       /* FALLTHROUGH */
+               case IGMP_G_QUERY_PENDING_MEMBER:
+               case IGMP_SG_QUERY_PENDING_MEMBER:
+                       inm_clear_recorded(inm);
+                       /* FALLTHROUGH */
+               case IGMP_REPORTING_MEMBER:
+                       inm->inm_state = IGMP_REPORTING_MEMBER;
+                       break;
+               }
+               /*
+                * Always clear state-change and group report timers.
+                * Free any pending IGMPv3 state-change records.
+                */
+               inm->inm_sctimer = 0;
+               inm->inm_timer = 0;
+               IF_DRAIN(&inm->inm_scq);
+next:
+               INM_UNLOCK(inm);
+               IN_NEXT_MULTI(step, inm);
+       }
+       in_multihead_lock_done();
+
+       IGI_LOCK(igi);
+}
+
+/*
+ * Update the Older Version Querier Present timers for a link.
+ * See Section 7.2.1 of RFC 3376.
+ */
+static void
+igmp_v1v2_process_querier_timers(struct igmp_ifinfo *igi)
+{
+       IGI_LOCK_ASSERT_HELD(igi);
+
+       if (igi->igi_v1_timer == 0 && igi->igi_v2_timer == 0) {
+               /*
+                * IGMPv1 and IGMPv2 Querier Present timers expired.
+                *
+                * Revert to IGMPv3.
+                */
+               if (igi->igi_version != IGMP_VERSION_3) {
+                       IGMP_PRINTF(("%s: transition from v%d -> v%d "
+                           "on 0x%llx(%s)\n", __func__,
+                           igi->igi_version, IGMP_VERSION_3,
+                           (uint64_t)VM_KERNEL_ADDRPERM(igi->igi_ifp),
+                           if_name(igi->igi_ifp)));
+                       igi->igi_version = IGMP_VERSION_3;
+                       IF_DRAIN(&igi->igi_v2q);
+               }
+       } else if (igi->igi_v1_timer == 0 && igi->igi_v2_timer > 0) {
+               /*
+                * IGMPv1 Querier Present timer expired,
+                * IGMPv2 Querier Present timer running.
+                * If IGMPv2 was disabled since last timeout,
+                * revert to IGMPv3.
+                * If IGMPv2 is enabled, revert to IGMPv2.
+                */
+               if (!igmp_v2enable) {
+                       IGMP_PRINTF(("%s: transition from v%d -> v%d "
+                           "on 0x%llx(%s%d)\n", __func__,
+                           igi->igi_version, IGMP_VERSION_3,
+                           (uint64_t)VM_KERNEL_ADDRPERM(igi->igi_ifp),
+                           igi->igi_ifp->if_name, igi->igi_ifp->if_unit));
+                       igi->igi_v2_timer = 0;
+                       igi->igi_version = IGMP_VERSION_3;
+                       IF_DRAIN(&igi->igi_v2q);
+               } else {
+                       --igi->igi_v2_timer;
+                       if (igi->igi_version != IGMP_VERSION_2) {
+                               IGMP_PRINTF(("%s: transition from v%d -> v%d "
+                                   "on 0x%llx(%s)\n", __func__,
+                                   igi->igi_version, IGMP_VERSION_2,
+                                   (uint64_t)VM_KERNEL_ADDRPERM(igi->igi_ifp),
+                                   if_name(igi->igi_ifp)));
+                               igi->igi_version = IGMP_VERSION_2;
+                               IF_DRAIN(&igi->igi_gq);
+                               igmp_v3_cancel_link_timers(igi);
+                       }
+               }
+       } else if (igi->igi_v1_timer > 0) {
+               /*
+                * IGMPv1 Querier Present timer running.
+                * Stop IGMPv2 timer if running.
+                *
+                * If IGMPv1 was disabled since last timeout,
+                * revert to IGMPv3.
+                * If IGMPv1 is enabled, reset IGMPv2 timer if running.
+                */
+               if (!igmp_v1enable) {
+                       IGMP_PRINTF(("%s: transition from v%d -> v%d "
+                           "on 0x%llx(%s%d)\n", __func__,
+                           igi->igi_version, IGMP_VERSION_3,
+                           (uint64_t)VM_KERNEL_ADDRPERM(igi->igi_ifp),
+                           igi->igi_ifp->if_name, igi->igi_ifp->if_unit));
+                       igi->igi_v1_timer = 0;
+                       igi->igi_version = IGMP_VERSION_3;
+                       IF_DRAIN(&igi->igi_v2q);
+               } else {
+                       --igi->igi_v1_timer;
+               }
+               if (igi->igi_v2_timer > 0) {
+                       IGMP_PRINTF(("%s: cancel v2 timer on 0x%llx(%s%d)\n",
+                           __func__,
+                           (uint64_t)VM_KERNEL_ADDRPERM(igi->igi_ifp),
+                           igi->igi_ifp->if_name, igi->igi_ifp->if_unit));
+                       igi->igi_v2_timer = 0;
+               }
+       }
+}
+
+/*
+ * Dispatch an IGMPv1/v2 host report or leave message.
+ * These are always small enough to fit inside a single mbuf.
+ */
+static int
+igmp_v1v2_queue_report(struct in_multi *inm, const int type)
+{
+       struct ifnet            *ifp;
+       struct igmp             *igmp;
+       struct ip               *ip;
+       struct mbuf             *m;
+       int                     error = 0;
+
+       INM_LOCK_ASSERT_HELD(inm);
+       IGI_LOCK_ASSERT_HELD(inm->inm_igi);
+
+       ifp = inm->inm_ifp;
+
+       MGETHDR(m, M_DONTWAIT, MT_DATA);
+       if (m == NULL)
+               return (ENOMEM);
+       MH_ALIGN(m, sizeof(struct ip) + sizeof(struct igmp));
+
+       m->m_pkthdr.len = sizeof(struct ip) + sizeof(struct igmp);
+
+       m->m_data += sizeof(struct ip);
+       m->m_len = sizeof(struct igmp);
+
+       igmp = mtod(m, struct igmp *);
+       igmp->igmp_type = type;
+       igmp->igmp_code = 0;
+       igmp->igmp_group = inm->inm_addr;
+       igmp->igmp_cksum = 0;
+       igmp->igmp_cksum = in_cksum(m, sizeof(struct igmp));
+
+       m->m_data -= sizeof(struct ip);
+       m->m_len += sizeof(struct ip);
+
+       ip = mtod(m, struct ip *);
+       ip->ip_tos = 0;
+       ip->ip_len = sizeof(struct ip) + sizeof(struct igmp);
+       ip->ip_off = 0;
+       ip->ip_p = IPPROTO_IGMP;
+       ip->ip_src.s_addr = INADDR_ANY;
+
+       if (type == IGMP_HOST_LEAVE_MESSAGE)
+               ip->ip_dst.s_addr = htonl(INADDR_ALLRTRS_GROUP);
+       else
+               ip->ip_dst = inm->inm_addr;
+
+       igmp_save_context(m, ifp);
+
+       m->m_flags |= M_IGMPV2;
+       if (inm->inm_igi->igi_flags & IGIF_LOOPBACK)
+               m->m_flags |= M_IGMP_LOOP;
+
+       /*
+        * Due to the fact that at this point we are possibly holding
+        * in_multihead_lock in shared or exclusive mode, we can't call
+        * igmp_sendpkt() here since that will eventually call ip_output(),
+        * which will try to lock in_multihead_lock and cause a deadlock.
+        * Instead we defer the work to the igmp_timeout() thread, thus
+        * avoiding unlocking in_multihead_lock here.
+        */
+       if (IF_QFULL(&inm->inm_igi->igi_v2q)) {
+               IGMP_PRINTF(("%s: v1/v2 outbound queue full\n", __func__));
+               error = ENOMEM;
+               m_freem(m);
+       } else {
+               IF_ENQUEUE(&inm->inm_igi->igi_v2q, m);
+               VERIFY(error == 0);
+       }
+       return (error);
+}
+
+/*
+ * Process a state change from the upper layer for the given IPv4 group.
+ *
+ * Each socket holds a reference on the in_multi in its own ip_moptions.
+ * The socket layer will have made the necessary updates to the group
+ * state, it is now up to IGMP to issue a state change report if there
+ * has been any change between T0 (when the last state-change was issued)
+ * and T1 (now).
+ *
+ * We use the IGMPv3 state machine at group level. The IGMP module
+ * however makes the decision as to which IGMP protocol version to speak.
+ * A state change *from* INCLUDE {} always means an initial join.
+ * A state change *to* INCLUDE {} always means a final leave.
+ *
+ * FUTURE: If IGIF_V3LITE is enabled for this interface, then we can
+ * save ourselves a bunch of work; any exclusive mode groups need not
+ * compute source filter lists.
+ */
+int
+igmp_change_state(struct in_multi *inm, struct igmp_tparams *itp)
+{
+       struct igmp_ifinfo *igi;
+       struct ifnet *ifp;
+       int error = 0;
+
+       VERIFY(itp != NULL);
+       bzero(itp, sizeof (*itp));
+
+       INM_LOCK_ASSERT_HELD(inm);
+       VERIFY(inm->inm_igi != NULL);
+       IGI_LOCK_ASSERT_NOTHELD(inm->inm_igi);
+
+       /*
+        * Try to detect if the upper layer just asked us to change state
+        * for an interface which has now gone away.
+        */
+       VERIFY(inm->inm_ifma != NULL);
+       ifp = inm->inm_ifma->ifma_ifp;
+       /*
+        * Sanity check that netinet's notion of ifp is the same as net's.
+        */
+       VERIFY(inm->inm_ifp == ifp);
+
+       igi = IGMP_IFINFO(ifp);
+       VERIFY(igi != NULL);
+
+       /*
+        * If we detect a state transition to or from MCAST_UNDEFINED
+        * for this group, then we are starting or finishing an IGMP
+        * life cycle for this group.
+        */
+       if (inm->inm_st[1].iss_fmode != inm->inm_st[0].iss_fmode) {
+               IGMP_PRINTF(("%s: inm transition %d -> %d\n", __func__,
+                   inm->inm_st[0].iss_fmode, inm->inm_st[1].iss_fmode));
+               if (inm->inm_st[0].iss_fmode == MCAST_UNDEFINED) {
+                       IGMP_PRINTF(("%s: initial join\n", __func__));
+                       error = igmp_initial_join(inm, igi, itp);
+                       goto out;
+               } else if (inm->inm_st[1].iss_fmode == MCAST_UNDEFINED) {
+                       IGMP_PRINTF(("%s: final leave\n", __func__));
+                       igmp_final_leave(inm, igi, itp);
+                       goto out;
+               }
+       } else {
+               IGMP_PRINTF(("%s: filter set change\n", __func__));
+       }
+
+       error = igmp_handle_state_change(inm, igi, itp);
+out:
+       return (error);
+}
+
+/*
+ * Perform the initial join for an IGMP group.
+ *
+ * When joining a group:
+ *  If the group should have its IGMP traffic suppressed, do nothing.
+ *  IGMPv1 starts sending IGMPv1 host membership reports.
+ *  IGMPv2 starts sending IGMPv2 host membership reports.
+ *  IGMPv3 will schedule an IGMPv3 state-change report containing the
+ *  initial state of the membership.
+ */
+static int
+igmp_initial_join(struct in_multi *inm, struct igmp_ifinfo *igi,
+    struct igmp_tparams *itp)
+{
+       struct ifnet            *ifp;
+       struct ifqueue          *ifq;
+       int                      error, retval, syncstates;
+
+       INM_LOCK_ASSERT_HELD(inm);
+       IGI_LOCK_ASSERT_NOTHELD(igi);
+       VERIFY(itp != NULL);
+
+       IGMP_INET_PRINTF(inm->inm_addr,
+           ("%s: initial join %s on ifp 0x%llx(%s)\n", __func__,
+           _igmp_inet_buf, (uint64_t)VM_KERNEL_ADDRPERM(inm->inm_ifp),
+           if_name(inm->inm_ifp)));
+
+       error = 0;
+       syncstates = 1;
+
+       ifp = inm->inm_ifp;
+
+       IGI_LOCK(igi);
+       VERIFY(igi->igi_ifp == ifp);
+
+       /*
+        * Groups joined on loopback or marked as 'not reported',
+        * e.g. 224.0.0.1, enter the IGMP_SILENT_MEMBER state and
+        * are never reported in any IGMP protocol exchanges.
+        * All other groups enter the appropriate IGMP state machine
+        * for the version in use on this link.
+        * A link marked as IGIF_SILENT causes IGMP to be completely
+        * disabled for the link.
+        */
+       if ((ifp->if_flags & IFF_LOOPBACK) ||
+           (igi->igi_flags & IGIF_SILENT) ||
+           !igmp_isgroupreported(inm->inm_addr)) {
+               IGMP_PRINTF(("%s: not kicking state machine for silent group\n",
+                   __func__));
+               inm->inm_state = IGMP_SILENT_MEMBER;
+               inm->inm_timer = 0;
+       } else {
+               /*
+                * Deal with overlapping in_multi lifecycle.
+                * If this group was LEAVING, then make sure
+                * we drop the reference we picked up to keep the
+                * group around for the final INCLUDE {} enqueue.
+                * Since we cannot call in_multi_detach() here,
+                * defer this task to the timer routine.
+                */
+               if (igi->igi_version == IGMP_VERSION_3 &&
+                   inm->inm_state == IGMP_LEAVING_MEMBER) {
+                       VERIFY(inm->inm_nrelecnt != 0);
+                       SLIST_INSERT_HEAD(&igi->igi_relinmhead, inm, inm_nrele);
+               }
+
+               inm->inm_state = IGMP_REPORTING_MEMBER;
+
+               switch (igi->igi_version) {
+               case IGMP_VERSION_1:
+               case IGMP_VERSION_2:
+                       inm->inm_state = IGMP_IDLE_MEMBER;
+                       error = igmp_v1v2_queue_report(inm,
+                           (igi->igi_version == IGMP_VERSION_2) ?
+                            IGMP_v2_HOST_MEMBERSHIP_REPORT :
+                            IGMP_v1_HOST_MEMBERSHIP_REPORT);
+
+                       INM_LOCK_ASSERT_HELD(inm);
+                       IGI_LOCK_ASSERT_HELD(igi);
+
+                       if (error == 0) {
+                               inm->inm_timer =
+                                   IGMP_RANDOM_DELAY(IGMP_V1V2_MAX_RI);
+                               itp->cst = 1;
+                       }
+                       break;
+
+               case IGMP_VERSION_3:
+                       /*
+                        * Defer update of T0 to T1, until the first copy
+                        * of the state change has been transmitted.
+                        */
+                       syncstates = 0;
+
+                       /*
+                        * Immediately enqueue a State-Change Report for
+                        * this interface, freeing any previous reports.
+                        * Don't kick the timers if there is nothing to do,
+                        * or if an error occurred.
+                        */
+                       ifq = &inm->inm_scq;
+                       IF_DRAIN(ifq);
+                       retval = igmp_v3_enqueue_group_record(ifq, inm, 1,
+                           0, 0);
+                       itp->cst = (ifq->ifq_len > 0);
+                       IGMP_PRINTF(("%s: enqueue record = %d\n",
+                           __func__, retval));
+                       if (retval <= 0) {
+                               error = retval * -1;
+                               break;
+                       }
+
+                       /*
+                        * Schedule transmission of pending state-change
+                        * report up to RV times for this link. The timer
+                        * will fire at the next igmp_timeout (1 second),
+                        * giving us an opportunity to merge the reports.
+                        */
+                       if (igi->igi_flags & IGIF_LOOPBACK) {
+                               inm->inm_scrv = 1;
+                       } else {
+                               VERIFY(igi->igi_rv > 1);
+                               inm->inm_scrv = igi->igi_rv;
+                       }
+                       inm->inm_sctimer = 1;
+                       itp->sct = 1;
+
+                       error = 0;
+                       break;
+               }
+       }
+       IGI_UNLOCK(igi);
+
+       /*
+        * Only update the T0 state if state change is atomic,
+        * i.e. we don't need to wait for a timer to fire before we
+        * can consider the state change to have been communicated.
+        */
+       if (syncstates) {
+               inm_commit(inm);
+               IGMP_INET_PRINTF(inm->inm_addr,
+                   ("%s: T1 -> T0 for %s/%s\n", __func__,
+                   _igmp_inet_buf, if_name(inm->inm_ifp)));
+       }
+
+       return (error);
+}
+
+/*
+ * Issue an intermediate state change during the IGMP life-cycle.
+ */
+static int
+igmp_handle_state_change(struct in_multi *inm, struct igmp_ifinfo *igi,
+    struct igmp_tparams *itp)
+{
+       struct ifnet            *ifp;
+       int                      retval = 0;
+
+       INM_LOCK_ASSERT_HELD(inm);
+       IGI_LOCK_ASSERT_NOTHELD(igi);
+       VERIFY(itp != NULL);
+
+       IGMP_INET_PRINTF(inm->inm_addr,
+           ("%s: state change for %s on ifp 0x%llx(%s)\n", __func__,
+           _igmp_inet_buf, (uint64_t)VM_KERNEL_ADDRPERM(inm->inm_ifp),
+           if_name(inm->inm_ifp)));
+
+       ifp = inm->inm_ifp;
+
+       IGI_LOCK(igi);
+       VERIFY(igi->igi_ifp == ifp);
+
+       if ((ifp->if_flags & IFF_LOOPBACK) ||
+           (igi->igi_flags & IGIF_SILENT) ||
+           !igmp_isgroupreported(inm->inm_addr) ||
+           (igi->igi_version != IGMP_VERSION_3)) {
+               IGI_UNLOCK(igi);
+               if (!igmp_isgroupreported(inm->inm_addr)) {
+                       IGMP_PRINTF(("%s: not kicking state "
+                           "machine for silent group\n", __func__));
+               }
+               IGMP_PRINTF(("%s: nothing to do\n", __func__));
+               inm_commit(inm);
+               IGMP_INET_PRINTF(inm->inm_addr,
+                   ("%s: T1 -> T0 for %s/%s\n", __func__,
+                   _igmp_inet_buf, inm->inm_ifp->if_name));
+               goto done;
+       }
+
+       IF_DRAIN(&inm->inm_scq);
+
+       retval = igmp_v3_enqueue_group_record(&inm->inm_scq, inm, 1, 0, 0);
+       itp->cst = (inm->inm_scq.ifq_len > 0);
+       IGMP_PRINTF(("%s: enqueue record = %d\n", __func__, retval));
+       if (retval <= 0) {
+               IGI_UNLOCK(igi);
+               retval *= -1;
+               goto done;
+       }
+       /*
+        * If record(s) were enqueued, start the state-change
+        * report timer for this group.
+        */
+       inm->inm_scrv = ((igi->igi_flags & IGIF_LOOPBACK) ? 1 : igi->igi_rv);
+       inm->inm_sctimer = 1;
+       itp->sct = 1;
+       IGI_UNLOCK(igi);
+done:
+       return (retval);
+}
+
+/*
+ * Perform the final leave for an IGMP group.
+ *
+ * When leaving a group:
+ *  IGMPv1 does nothing.
+ *  IGMPv2 sends a host leave message, if and only if we are the reporter.
+ *  IGMPv3 enqueues a state-change report containing a transition
+ *  to INCLUDE {} for immediate transmission.
+ */
+static void
+igmp_final_leave(struct in_multi *inm, struct igmp_ifinfo *igi,
+    struct igmp_tparams *itp)
+{
+       int syncstates = 1;
+
+       INM_LOCK_ASSERT_HELD(inm);
+       IGI_LOCK_ASSERT_NOTHELD(igi);
+       VERIFY(itp != NULL);
+
+       IGMP_INET_PRINTF(inm->inm_addr,
+           ("%s: final leave %s on ifp 0x%llx(%s)\n", __func__,
+           _igmp_inet_buf, (uint64_t)VM_KERNEL_ADDRPERM(inm->inm_ifp),
+           if_name(inm->inm_ifp)));
+
+       switch (inm->inm_state) {
+       case IGMP_NOT_MEMBER:
+       case IGMP_SILENT_MEMBER:
+       case IGMP_LEAVING_MEMBER:
+               /* Already leaving or left; do nothing. */
+               IGMP_PRINTF(("%s: not kicking state machine for silent group\n",
+                   __func__));
+               break;
+       case IGMP_REPORTING_MEMBER:
+       case IGMP_IDLE_MEMBER:
+       case IGMP_G_QUERY_PENDING_MEMBER:
+       case IGMP_SG_QUERY_PENDING_MEMBER:
+               IGI_LOCK(igi);
+               if (igi->igi_version == IGMP_VERSION_2) {
+                       if (inm->inm_state == IGMP_G_QUERY_PENDING_MEMBER ||
+                           inm->inm_state == IGMP_SG_QUERY_PENDING_MEMBER) {
+                               panic("%s: IGMPv3 state reached, not IGMPv3 "
+                                   "mode\n", __func__);
+                               /* NOTREACHED */
+                       }
+                       /* scheduler timer if enqueue is successful */
+                       itp->cst = (igmp_v1v2_queue_report(inm,
+                           IGMP_HOST_LEAVE_MESSAGE) == 0);
+
+                       INM_LOCK_ASSERT_HELD(inm);
+                       IGI_LOCK_ASSERT_HELD(igi);
+
+                       inm->inm_state = IGMP_NOT_MEMBER;
+               } else if (igi->igi_version == IGMP_VERSION_3) {
+                       /*
+                        * Stop group timer and all pending reports.
+                        * Immediately enqueue a state-change report
+                        * TO_IN {} to be sent on the next timeout,
+                        * giving us an opportunity to merge reports.
+                        */
+                       IF_DRAIN(&inm->inm_scq);
+                       inm->inm_timer = 0;
+                       if (igi->igi_flags & IGIF_LOOPBACK) {
+                               inm->inm_scrv = 1;
+                       } else {
+                               inm->inm_scrv = igi->igi_rv;
+                       }
+                       IGMP_INET_PRINTF(inm->inm_addr,
+                           ("%s: Leaving %s/%s with %d "
+                           "pending retransmissions.\n", __func__,
+                           _igmp_inet_buf, if_name(inm->inm_ifp),
+                           inm->inm_scrv));
+                       if (inm->inm_scrv == 0) {
+                               inm->inm_state = IGMP_NOT_MEMBER;
+                               inm->inm_sctimer = 0;
+                       } else {
+                               int retval;
+                               /*
+                                * Stick around in the in_multihead list;
+                                * the final detach will be issued by
+                                * igmp_v3_process_group_timers() when
+                                * the retransmit timer expires.
+                                */
+                               INM_ADDREF_LOCKED(inm);
+                               VERIFY(inm->inm_debug & IFD_ATTACHED);
+                               inm->inm_reqcnt++;
+                               VERIFY(inm->inm_reqcnt >= 1);
+                               inm->inm_nrelecnt++;
+                               VERIFY(inm->inm_nrelecnt != 0);
+
+                               retval = igmp_v3_enqueue_group_record(
+                                   &inm->inm_scq, inm, 1, 0, 0);
+                               itp->cst = (inm->inm_scq.ifq_len > 0);
+                               KASSERT(retval != 0,
+                                   ("%s: enqueue record = %d\n", __func__,
+                                    retval));
+
+                               inm->inm_state = IGMP_LEAVING_MEMBER;
+                               inm->inm_sctimer = 1;
+                               itp->sct = 1;
+                               syncstates = 0;
+                       }
+               }
+               IGI_UNLOCK(igi);
+               break;
+       case IGMP_LAZY_MEMBER:
+       case IGMP_SLEEPING_MEMBER:
+       case IGMP_AWAKENING_MEMBER:
+               /* Our reports are suppressed; do nothing. */
+               break;
+       }
+
+       if (syncstates) {
+               inm_commit(inm);
+               IGMP_INET_PRINTF(inm->inm_addr,
+                   ("%s: T1 -> T0 for %s/%s\n", __func__,
+                   _igmp_inet_buf, if_name(inm->inm_ifp)));
+               inm->inm_st[1].iss_fmode = MCAST_UNDEFINED;
+               IGMP_INET_PRINTF(inm->inm_addr,
+                   ("%s: T1 now MCAST_UNDEFINED for %s/%s\n",
+                   __func__, _igmp_inet_buf, if_name(inm->inm_ifp)));
+       }
+}
+
+/*
+ * Enqueue an IGMPv3 group record to the given output queue.
+ *
+ * XXX This function could do with having the allocation code
+ * split out, and the multiple-tree-walks coalesced into a single
+ * routine as has been done in igmp_v3_enqueue_filter_change().
+ *
+ * If is_state_change is zero, a current-state record is appended.
+ * If is_state_change is non-zero, a state-change report is appended.
+ *
+ * If is_group_query is non-zero, an mbuf packet chain is allocated.
+ * If is_group_query is zero, and if there is a packet with free space
+ * at the tail of the queue, it will be appended to providing there
+ * is enough free space.
+ * Otherwise a new mbuf packet chain is allocated.
+ *
+ * If is_source_query is non-zero, each source is checked to see if
+ * it was recorded for a Group-Source query, and will be omitted if
+ * it is not both in-mode and recorded.
+ *
+ * The function will attempt to allocate leading space in the packet
+ * for the IP/IGMP header to be prepended without fragmenting the chain.
+ *
+ * If successful the size of all data appended to the queue is returned,
+ * otherwise an error code less than zero is returned, or zero if
+ * no record(s) were appended.
+ */
+static int
+igmp_v3_enqueue_group_record(struct ifqueue *ifq, struct in_multi *inm,
+    const int is_state_change, const int is_group_query,
+    const int is_source_query)
+{
+       struct igmp_grouprec     ig;
+       struct igmp_grouprec    *pig;
+       struct ifnet            *ifp;
+       struct ip_msource       *ims, *nims;
+       struct mbuf             *m0, *m, *md;
+       int                      error, is_filter_list_change;
+       int                      minrec0len, m0srcs, msrcs, nbytes, off;
+       int                      record_has_sources;
+       int                      now;
+       int                      type;
+       in_addr_t                naddr;
+       uint8_t                  mode;
+       u_int16_t                ig_numsrc;
+
+       INM_LOCK_ASSERT_HELD(inm);
+       IGI_LOCK_ASSERT_HELD(inm->inm_igi);
+
+       error = 0;
+       ifp = inm->inm_ifp;
+       is_filter_list_change = 0;
+       m = NULL;
+       m0 = NULL;
+       m0srcs = 0;
+       msrcs = 0;
+       nbytes = 0;
+       nims = NULL;
+       record_has_sources = 1;
+       pig = NULL;
+       type = IGMP_DO_NOTHING;
+       mode = inm->inm_st[1].iss_fmode;
+
+       /*
+        * If we did not transition out of ASM mode during t0->t1,
+        * and there are no source nodes to process, we can skip
+        * the generation of source records.
+        */
+       if (inm->inm_st[0].iss_asm > 0 && inm->inm_st[1].iss_asm > 0 &&
+           inm->inm_nsrc == 0)
+               record_has_sources = 0;
+
+       if (is_state_change) {
+               /*
+                * Queue a state change record.
+                * If the mode did not change, and there are non-ASM
+                * listeners or source filters present,
+                * we potentially need to issue two records for the group.
+                * If we are transitioning to MCAST_UNDEFINED, we need
+                * not send any sources.
+                * If there are ASM listeners, and there was no filter
+                * mode transition of any kind, do nothing.
+                */
+               if (mode != inm->inm_st[0].iss_fmode) {
+                       if (mode == MCAST_EXCLUDE) {
+                               IGMP_PRINTF(("%s: change to EXCLUDE\n",
+                                   __func__));
+                               type = IGMP_CHANGE_TO_EXCLUDE_MODE;
+                       } else {
+                               IGMP_PRINTF(("%s: change to INCLUDE\n",
+                                   __func__));
+                               type = IGMP_CHANGE_TO_INCLUDE_MODE;
+                               if (mode == MCAST_UNDEFINED)
+                                       record_has_sources = 0;
+                       }
+               } else {
+                       if (record_has_sources) {
+                               is_filter_list_change = 1;
+                       } else {
+                               type = IGMP_DO_NOTHING;
+                       }
+               }
+       } else {
+               /*
+                * Queue a current state record.
+                */
+               if (mode == MCAST_EXCLUDE) {
+                       type = IGMP_MODE_IS_EXCLUDE;
+               } else if (mode == MCAST_INCLUDE) {
+                       type = IGMP_MODE_IS_INCLUDE;
+                       VERIFY(inm->inm_st[1].iss_asm == 0);
+               }
+       }
+
+       /*
+        * Generate the filter list changes using a separate function.
+        */
+       if (is_filter_list_change)
+               return (igmp_v3_enqueue_filter_change(ifq, inm));
+
+       if (type == IGMP_DO_NOTHING) {
+               IGMP_INET_PRINTF(inm->inm_addr,
+                   ("%s: nothing to do for %s/%s\n",
+                   __func__, _igmp_inet_buf,
+                   if_name(inm->inm_ifp)));
+               return (0);
+       }
+
+       /*
+        * If any sources are present, we must be able to fit at least
+        * one in the trailing space of the tail packet's mbuf,
+        * ideally more.
+        */
+       minrec0len = sizeof(struct igmp_grouprec);
+       if (record_has_sources)
+               minrec0len += sizeof(in_addr_t);
+
+       IGMP_INET_PRINTF(inm->inm_addr,
+           ("%s: queueing %s for %s/%s\n", __func__,
+           igmp_rec_type_to_str(type), _igmp_inet_buf,
+           if_name(inm->inm_ifp)));
+
+       /*
+        * Check if we have a packet in the tail of the queue for this
+        * group into which the first group record for this group will fit.
+        * Otherwise allocate a new packet.
+        * Always allocate leading space for IP+RA_OPT+IGMP+REPORT.
+        * Note: Group records for G/GSR query responses MUST be sent
+        * in their own packet.
+        */
+       m0 = ifq->ifq_tail;
+       if (!is_group_query &&
+           m0 != NULL &&
+           (m0->m_pkthdr.vt_nrecs + 1 <= IGMP_V3_REPORT_MAXRECS) &&
+           (m0->m_pkthdr.len + minrec0len) <
+            (ifp->if_mtu - IGMP_LEADINGSPACE)) {
+               m0srcs = (ifp->if_mtu - m0->m_pkthdr.len -
+                           sizeof(struct igmp_grouprec)) / sizeof(in_addr_t);
+               m = m0;
+               IGMP_PRINTF(("%s: use existing packet\n", __func__));
+       } else {
+               if (IF_QFULL(ifq)) {
+                       IGMP_PRINTF(("%s: outbound queue full\n", __func__));
+                       return (-ENOMEM);
+               }
+               m = NULL;
+               m0srcs = (ifp->if_mtu - IGMP_LEADINGSPACE -
+                   sizeof(struct igmp_grouprec)) / sizeof(in_addr_t);
+               if (!is_state_change && !is_group_query) {
+                       m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
+                       if (m)
+                               m->m_data += IGMP_LEADINGSPACE;
+               }
+               if (m == NULL) {
+                       m = m_gethdr(M_DONTWAIT, MT_DATA);
+                       if (m)
+                               MH_ALIGN(m, IGMP_LEADINGSPACE);
+               }
+               if (m == NULL)
+                       return (-ENOMEM);
+
+               igmp_save_context(m, ifp);
+
+               IGMP_PRINTF(("%s: allocated first packet\n", __func__));
+       }
+
+       /*
+        * Append group record.
+        * If we have sources, we don't know how many yet.
+        */
+       ig.ig_type = type;
+       ig.ig_datalen = 0;
+       ig.ig_numsrc = 0;
+       ig.ig_group = inm->inm_addr;
+       if (!m_append(m, sizeof(struct igmp_grouprec), (void *)&ig)) {
+               if (m != m0)
+                       m_freem(m);
+               IGMP_PRINTF(("%s: m_append() failed.\n", __func__));
+               return (-ENOMEM);
+       }
+       nbytes += sizeof(struct igmp_grouprec);
+
+       /*
+        * Append as many sources as will fit in the first packet.
+        * If we are appending to a new packet, the chain allocation
+        * may potentially use clusters; use m_getptr() in this case.
+        * If we are appending to an existing packet, we need to obtain
+        * a pointer to the group record after m_append(), in case a new
+        * mbuf was allocated.
+        * Only append sources which are in-mode at t1. If we are
+        * transitioning to MCAST_UNDEFINED state on the group, do not
+        * include source entries.
+        * Only report recorded sources in our filter set when responding
+        * to a group-source query.
+        */
+       if (record_has_sources) {
+               if (m == m0) {
+                       md = m_last(m);
+                       pig = (struct igmp_grouprec *)(void *)
+                           (mtod(md, uint8_t *) + md->m_len - nbytes);
+               } else {
+                       md = m_getptr(m, 0, &off);
+                       pig = (struct igmp_grouprec *)(void *)
+                           (mtod(md, uint8_t *) + off);
+               }
+               msrcs = 0;
+               RB_FOREACH_SAFE(ims, ip_msource_tree, &inm->inm_srcs, nims) {
+#ifdef IGMP_DEBUG
+                       char buf[MAX_IPv4_STR_LEN];
+
+                       inet_ntop_haddr(ims->ims_haddr, buf, sizeof(buf));
+                       IGMP_PRINTF(("%s: visit node %s\n", __func__, buf));
+#endif
+                       now = ims_get_mode(inm, ims, 1);
+                       IGMP_PRINTF(("%s: node is %d\n", __func__, now));
+                       if ((now != mode) ||
+                           (now == mode && mode == MCAST_UNDEFINED)) {
+                               IGMP_PRINTF(("%s: skip node\n", __func__));
+                               continue;
+                       }
+                       if (is_source_query && ims->ims_stp == 0) {
+                               IGMP_PRINTF(("%s: skip unrecorded node\n",
+                                   __func__));
+                               continue;
+                       }
+                       IGMP_PRINTF(("%s: append node\n", __func__));
+                       naddr = htonl(ims->ims_haddr);
+                       if (!m_append(m, sizeof(in_addr_t), (void *)&naddr)) {
+                               if (m != m0)
+                                       m_freem(m);
+                               IGMP_PRINTF(("%s: m_append() failed.\n",
+                                   __func__));
+                               return (-ENOMEM);
+                       }
+                       nbytes += sizeof(in_addr_t);
+                       ++msrcs;
+                       if (msrcs == m0srcs)
+                               break;
+               }
+               IGMP_PRINTF(("%s: msrcs is %d this packet\n", __func__,
+                   msrcs));
+               ig_numsrc = htons(msrcs);
+               bcopy(&ig_numsrc, &pig->ig_numsrc, sizeof (ig_numsrc));
+               nbytes += (msrcs * sizeof(in_addr_t));
+       }
+
+       if (is_source_query && msrcs == 0) {
+               IGMP_PRINTF(("%s: no recorded sources to report\n", __func__));
+               if (m != m0)
+                       m_freem(m);
+               return (0);
+       }
+
+       /*
+        * We are good to go with first packet.
+        */
+       if (m != m0) {
+               IGMP_PRINTF(("%s: enqueueing first packet\n", __func__));
+               m->m_pkthdr.vt_nrecs = 1;
+               IF_ENQUEUE(ifq, m);
+       } else {
+               m->m_pkthdr.vt_nrecs++;
+       }
+       /*
+        * No further work needed if no source list in packet(s).
+        */
+       if (!record_has_sources)
+               return (nbytes);
+
+       /*
+        * Whilst sources remain to be announced, we need to allocate
+        * a new packet and fill out as many sources as will fit.
+        * Always try for a cluster first.
+        */
+       while (nims != NULL) {
+               if (IF_QFULL(ifq)) {
+                       IGMP_PRINTF(("%s: outbound queue full\n", __func__));
+                       return (-ENOMEM);
+               }
+               m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
+               if (m)
+                       m->m_data += IGMP_LEADINGSPACE;
+               if (m == NULL) {
+                       m = m_gethdr(M_DONTWAIT, MT_DATA);
+                       if (m)
+                               MH_ALIGN(m, IGMP_LEADINGSPACE);
+               }
+               if (m == NULL)
+                       return (-ENOMEM);
+               igmp_save_context(m, ifp);
+               md = m_getptr(m, 0, &off);
+               pig = (struct igmp_grouprec *)(void *)
+                   (mtod(md, uint8_t *) + off);
+               IGMP_PRINTF(("%s: allocated next packet\n", __func__));
+
+               if (!m_append(m, sizeof(struct igmp_grouprec), (void *)&ig)) {
+                       if (m != m0)
+                               m_freem(m);
+                       IGMP_PRINTF(("%s: m_append() failed.\n", __func__));
+                       return (-ENOMEM);
+               }
+               m->m_pkthdr.vt_nrecs = 1;
+               nbytes += sizeof(struct igmp_grouprec);
+
+               m0srcs = (ifp->if_mtu - IGMP_LEADINGSPACE -
+                   sizeof(struct igmp_grouprec)) / sizeof(in_addr_t);
+
+               msrcs = 0;
+               RB_FOREACH_FROM(ims, ip_msource_tree, nims) {
+#ifdef IGMP_DEBUG
+                       char buf[MAX_IPv4_STR_LEN];
+
+                       inet_ntop_haddr(ims->ims_haddr, buf, sizeof(buf));
+                       IGMP_PRINTF(("%s: visit node %s\n", __func__, buf));
+#endif
+                       now = ims_get_mode(inm, ims, 1);
+                       if ((now != mode) ||
+                           (now == mode && mode == MCAST_UNDEFINED)) {
+                               IGMP_PRINTF(("%s: skip node\n", __func__));
+                               continue;
+                       }
+                       if (is_source_query && ims->ims_stp == 0) {
+                               IGMP_PRINTF(("%s: skip unrecorded node\n",
+                                   __func__));
+                               continue;
+                       }
+                       IGMP_PRINTF(("%s: append node\n", __func__));
+                       naddr = htonl(ims->ims_haddr);
+                       if (!m_append(m, sizeof(in_addr_t), (void *)&naddr)) {
+                               if (m != m0)
+                                       m_freem(m);
+                               IGMP_PRINTF(("%s: m_append() failed.\n",
+                                   __func__));
+                               return (-ENOMEM);
+                       }
+                       ++msrcs;
+                       if (msrcs == m0srcs)
+                               break;
+               }
+               ig_numsrc = htons(msrcs);
+               bcopy(&ig_numsrc, &pig->ig_numsrc, sizeof (ig_numsrc));
+               nbytes += (msrcs * sizeof(in_addr_t));
+
+               IGMP_PRINTF(("%s: enqueueing next packet\n", __func__));
+               IF_ENQUEUE(ifq, m);
+       }
+
+       return (nbytes);
+}
+
+/*
+ * Type used to mark record pass completion.
+ * We exploit the fact we can cast to this easily from the
+ * current filter modes on each ip_msource node.
+ */
+typedef enum {
+       REC_NONE = 0x00,        /* MCAST_UNDEFINED */
+       REC_ALLOW = 0x01,       /* MCAST_INCLUDE */
+       REC_BLOCK = 0x02,       /* MCAST_EXCLUDE */
+       REC_FULL = REC_ALLOW | REC_BLOCK
+} rectype_t;
+
+/*
+ * Enqueue an IGMPv3 filter list change to the given output queue.
+ *
+ * Source list filter state is held in an RB-tree. When the filter list
+ * for a group is changed without changing its mode, we need to compute
+ * the deltas between T0 and T1 for each source in the filter set,
+ * and enqueue the appropriate ALLOW_NEW/BLOCK_OLD records.
+ *
+ * As we may potentially queue two record types, and the entire R-B tree
+ * needs to be walked at once, we break this out into its own function
+ * so we can generate a tightly packed queue of packets.
+ *
+ * XXX This could be written to only use one tree walk, although that makes
+ * serializing into the mbuf chains a bit harder. For now we do two walks
+ * which makes things easier on us, and it may or may not be harder on
+ * the L2 cache.
+ *
+ * If successful the size of all data appended to the queue is returned,
+ * otherwise an error code less than zero is returned, or zero if
+ * no record(s) were appended.
+ */
+static int
+igmp_v3_enqueue_filter_change(struct ifqueue *ifq, struct in_multi *inm)
+{
+       static const int MINRECLEN =
+           sizeof(struct igmp_grouprec) + sizeof(in_addr_t);
+       struct ifnet            *ifp;
+       struct igmp_grouprec     ig;
+       struct igmp_grouprec    *pig;
+       struct ip_msource       *ims, *nims;
+       struct mbuf             *m, *m0, *md;
+       in_addr_t                naddr;
+       int                      m0srcs, nbytes, npbytes, off, rsrcs, schanged;
+       int                      nallow, nblock;
+       uint8_t                  mode, now, then;
+       rectype_t                crt, drt, nrt;
+       u_int16_t                ig_numsrc;
+
+       INM_LOCK_ASSERT_HELD(inm);
+
+       if (inm->inm_nsrc == 0 ||
+           (inm->inm_st[0].iss_asm > 0 && inm->inm_st[1].iss_asm > 0))
+               return (0);
+
+       ifp = inm->inm_ifp;                     /* interface */
+       mode = inm->inm_st[1].iss_fmode;        /* filter mode at t1 */
+       crt = REC_NONE; /* current group record type */
+       drt = REC_NONE; /* mask of completed group record types */
+       nrt = REC_NONE; /* record type for current node */
+       m0srcs = 0;     /* # source which will fit in current mbuf chain */
+       nbytes = 0;     /* # of bytes appended to group's state-change queue */
+       npbytes = 0;    /* # of bytes appended this packet */
+       rsrcs = 0;      /* # sources encoded in current record */
+       schanged = 0;   /* # nodes encoded in overall filter change */
+       nallow = 0;     /* # of source entries in ALLOW_NEW */
+       nblock = 0;     /* # of source entries in BLOCK_OLD */
+       nims = NULL;    /* next tree node pointer */
+
+       /*
+        * For each possible filter record mode.
+        * The first kind of source we encounter tells us which
+        * is the first kind of record we start appending.
+        * If a node transitioned to UNDEFINED at t1, its mode is treated
+        * as the inverse of the group's filter mode.
+        */
+       while (drt != REC_FULL) {
+               do {
+                       m0 = ifq->ifq_tail;
+                       if (m0 != NULL &&
+                           (m0->m_pkthdr.vt_nrecs + 1 <=
+                            IGMP_V3_REPORT_MAXRECS) &&
+                           (m0->m_pkthdr.len + MINRECLEN) <
+                            (ifp->if_mtu - IGMP_LEADINGSPACE)) {
+                               m = m0;
+                               m0srcs = (ifp->if_mtu - m0->m_pkthdr.len -
+                                           sizeof(struct igmp_grouprec)) /
+                                   sizeof(in_addr_t);
+                               IGMP_PRINTF(("%s: use previous packet\n",
+                                   __func__));
+                       } else {
+                               m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
+                               if (m)
+                                       m->m_data += IGMP_LEADINGSPACE;
+                               if (m == NULL) {
+                                       m = m_gethdr(M_DONTWAIT, MT_DATA);
+                                       if (m)
+                                               MH_ALIGN(m, IGMP_LEADINGSPACE);
+                               }
+                               if (m == NULL) {
+                                       IGMP_PRINTF(("%s: m_get*() failed\n",
+                                           __func__));
+                                       return (-ENOMEM);
+                               }
+                               m->m_pkthdr.vt_nrecs = 0;
+                               igmp_save_context(m, ifp);
+                               m0srcs = (ifp->if_mtu - IGMP_LEADINGSPACE -
+                                   sizeof(struct igmp_grouprec)) /
+                                   sizeof(in_addr_t);
+                               npbytes = 0;
+                               IGMP_PRINTF(("%s: allocated new packet\n",
+                                   __func__));
+                       }
+                       /*
+                        * Append the IGMP group record header to the
+                        * current packet's data area.
+                        * Recalculate pointer to free space for next
+                        * group record, in case m_append() allocated
+                        * a new mbuf or cluster.
+                        */
+                       memset(&ig, 0, sizeof(ig));
+                       ig.ig_group = inm->inm_addr;
+                       if (!m_append(m, sizeof(ig), (void *)&ig)) {
+                               if (m != m0)
+                                       m_freem(m);
+                               IGMP_PRINTF(("%s: m_append() failed\n",
+                                   __func__));
+                               return (-ENOMEM);
+                       }
+                       npbytes += sizeof(struct igmp_grouprec);
+                       if (m != m0) {
+                               /* new packet; offset in c hain */
+                               md = m_getptr(m, npbytes -
+                                   sizeof(struct igmp_grouprec), &off);
+                               pig = (struct igmp_grouprec *)(void *)(mtod(md,
+                                   uint8_t *) + off);
+                       } else {
+                               /* current packet; offset from last append */
+                               md = m_last(m);
+                               pig = (struct igmp_grouprec *)(void *)(mtod(md,
+                                   uint8_t *) + md->m_len -
+                                   sizeof(struct igmp_grouprec));
+                       }
+                       /*
+                        * Begin walking the tree for this record type
+                        * pass, or continue from where we left off
+                        * previously if we had to allocate a new packet.
+                        * Only report deltas in-mode at t1.
+                        * We need not report included sources as allowed
+                        * if we are in inclusive mode on the group,
+                        * however the converse is not true.
+                        */
+                       rsrcs = 0;
+                       if (nims == NULL)
+                               nims = RB_MIN(ip_msource_tree, &inm->inm_srcs);
+                       RB_FOREACH_FROM(ims, ip_msource_tree, nims) {
+#ifdef IGMP_DEBUG
+                               char buf[MAX_IPv4_STR_LEN];
+
+                               inet_ntop_haddr(ims->ims_haddr, buf, sizeof(buf));
+                               IGMP_PRINTF(("%s: visit node %s\n", __func__, buf));
+#endif
+                               now = ims_get_mode(inm, ims, 1);
+                               then = ims_get_mode(inm, ims, 0);
+                               IGMP_PRINTF(("%s: mode: t0 %d, t1 %d\n",
+                                   __func__, then, now));
+                               if (now == then) {
+                                       IGMP_PRINTF(("%s: skip unchanged\n",
+                                           __func__));
+                                       continue;
+                               }
+                               if (mode == MCAST_EXCLUDE &&
+                                   now == MCAST_INCLUDE) {
+                                       IGMP_PRINTF(("%s: skip IN src on EX "
+                                           "group\n", __func__));
+                                       continue;
+                               }
+                               nrt = (rectype_t)now;
+                               if (nrt == REC_NONE)
+                                       nrt = (rectype_t)(~mode & REC_FULL);
+                               if (schanged++ == 0) {
+                                       crt = nrt;
+                               } else if (crt != nrt)
+                                       continue;
+                               naddr = htonl(ims->ims_haddr);
+                               if (!m_append(m, sizeof(in_addr_t),
+                                   (void *)&naddr)) {
+                                       if (m != m0)
+                                               m_freem(m);
+                                       IGMP_PRINTF(("%s: m_append() failed\n",
+                                           __func__));
+                                       return (-ENOMEM);
+                               }
+                               nallow += !!(crt == REC_ALLOW);
+                               nblock += !!(crt == REC_BLOCK);
+                               if (++rsrcs == m0srcs)
+                                       break;
+                       }
+                       /*
+                        * If we did not append any tree nodes on this
+                        * pass, back out of allocations.
+                        */
+                       if (rsrcs == 0) {
+                               npbytes -= sizeof(struct igmp_grouprec);
+                               if (m != m0) {
+                                       IGMP_PRINTF(("%s: m_free(m)\n",
+                                           __func__));
+                                       m_freem(m);
+                               } else {
+                                       IGMP_PRINTF(("%s: m_adj(m, -ig)\n",
+                                           __func__));
+                                       m_adj(m, -((int)sizeof(
+                                           struct igmp_grouprec)));
+                               }
+                               continue;
+                       }
+                       npbytes += (rsrcs * sizeof(in_addr_t));
+                       if (crt == REC_ALLOW)
+                               pig->ig_type = IGMP_ALLOW_NEW_SOURCES;
+                       else if (crt == REC_BLOCK)
+                               pig->ig_type = IGMP_BLOCK_OLD_SOURCES;
+                       ig_numsrc = htons(rsrcs);
+                       bcopy(&ig_numsrc, &pig->ig_numsrc, sizeof (ig_numsrc));
+                       /*
+                        * Count the new group record, and enqueue this
+                        * packet if it wasn't already queued.
+                        */
+                       m->m_pkthdr.vt_nrecs++;
+                       if (m != m0)
+                               IF_ENQUEUE(ifq, m);
+                       nbytes += npbytes;
+               } while (nims != NULL);
+               drt |= crt;
+               crt = (~crt & REC_FULL);
+       }
+
+       IGMP_PRINTF(("%s: queued %d ALLOW_NEW, %d BLOCK_OLD\n", __func__,
+           nallow, nblock));
+
+       return (nbytes);
+}
+
+static int
+igmp_v3_merge_state_changes(struct in_multi *inm, struct ifqueue *ifscq)
+{
+       struct ifqueue  *gq;
+       struct mbuf     *m;             /* pending state-change */
+       struct mbuf     *m0;            /* copy of pending state-change */
+       struct mbuf     *mt;            /* last state-change in packet */
+       struct mbuf     *n;
+       int              docopy, domerge;
+       u_int            recslen;
+
+       INM_LOCK_ASSERT_HELD(inm);
+
+       docopy = 0;
+       domerge = 0;
+       recslen = 0;
+
+       /*
+        * If there are further pending retransmissions, make a writable
+        * copy of each queued state-change message before merging.
+        */
+       if (inm->inm_scrv > 0)
+               docopy = 1;
+
+       gq = &inm->inm_scq;
+#ifdef IGMP_DEBUG
+       if (gq->ifq_head == NULL) {
+               IGMP_PRINTF(("%s: WARNING: queue for inm 0x%llx is empty\n",
+                   __func__, (uint64_t)VM_KERNEL_ADDRPERM(inm)));
+       }
+#endif
+
+       /*
+        * Use IF_REMQUEUE() instead of IF_DEQUEUE() below, since the
+        * packet might not always be at the head of the ifqueue.
+        */
+       m = gq->ifq_head;
+       while (m != NULL) {
+               /*
+                * Only merge the report into the current packet if
+                * there is sufficient space to do so; an IGMPv3 report
+                * packet may only contain 65,535 group records.
+                * Always use a simple mbuf chain concatentation to do this,
+                * as large state changes for single groups may have
+                * allocated clusters.
+                */
+               domerge = 0;
+               mt = ifscq->ifq_tail;
+               if (mt != NULL) {
+                       recslen = m_length(m);
+
+                       if ((mt->m_pkthdr.vt_nrecs +
+                           m->m_pkthdr.vt_nrecs <=
+                           IGMP_V3_REPORT_MAXRECS) &&
+                           (mt->m_pkthdr.len + recslen <=
+                           (inm->inm_ifp->if_mtu - IGMP_LEADINGSPACE)))
+                               domerge = 1;
+               }
+
+               if (!domerge && IF_QFULL(gq)) {
+                       IGMP_PRINTF(("%s: outbound queue full, skipping whole "
+                           "packet 0x%llx\n", __func__,
+                           (uint64_t)VM_KERNEL_ADDRPERM(m)));
+                       n = m->m_nextpkt;
+                       if (!docopy) {
+                               IF_REMQUEUE(gq, m);
+                               m_freem(m);
+                       }
+                       m = n;
+                       continue;
+               }
+
+               if (!docopy) {
+                       IGMP_PRINTF(("%s: dequeueing 0x%llx\n", __func__,
+                           (uint64_t)VM_KERNEL_ADDRPERM(m)));
+                       n = m->m_nextpkt;
+                       IF_REMQUEUE(gq, m);
+                       m0 = m;
+                       m = n;
+               } else {
+                       IGMP_PRINTF(("%s: copying 0x%llx\n", __func__,
+                           (uint64_t)VM_KERNEL_ADDRPERM(m)));
+                       m0 = m_dup(m, M_NOWAIT);
+                       if (m0 == NULL)
+                               return (ENOMEM);
+                       m0->m_nextpkt = NULL;
+                       m = m->m_nextpkt;
+               }
+
+               if (!domerge) {
+                       IGMP_PRINTF(("%s: queueing 0x%llx to ifscq 0x%llx)\n",
+                           __func__, (uint64_t)VM_KERNEL_ADDRPERM(m0),
+                           (uint64_t)VM_KERNEL_ADDRPERM(ifscq)));
+                       IF_ENQUEUE(ifscq, m0);
+               } else {
+                       struct mbuf *mtl;       /* last mbuf of packet mt */
+
+                       IGMP_PRINTF(("%s: merging 0x%llx with ifscq tail "
+                           "0x%llx)\n", __func__,
+                           (uint64_t)VM_KERNEL_ADDRPERM(m0),
+                           (uint64_t)VM_KERNEL_ADDRPERM(mt)));
+
+                       mtl = m_last(mt);
+                       m0->m_flags &= ~M_PKTHDR;
+                       mt->m_pkthdr.len += recslen;
+                       mt->m_pkthdr.vt_nrecs +=
+                           m0->m_pkthdr.vt_nrecs;
+
+                       mtl->m_next = m0;
+               }
+       }
+
+       return (0);
+}
+
+/*
+ * Respond to a pending IGMPv3 General Query.
+ */
+static uint32_t
+igmp_v3_dispatch_general_query(struct igmp_ifinfo *igi)
+{
+       struct ifnet            *ifp;
+       struct in_multi         *inm;
+       struct in_multistep     step;
+       int                      retval, loop;
+
+       IGI_LOCK_ASSERT_HELD(igi);
+
+       VERIFY(igi->igi_version == IGMP_VERSION_3);
+
+       ifp = igi->igi_ifp;
+       IGI_UNLOCK(igi);
+
+       in_multihead_lock_shared();
+       IN_FIRST_MULTI(step, inm);
+       while (inm != NULL) {
+               INM_LOCK(inm);
+               if (inm->inm_ifp != ifp)
+                       goto next;
+
+               switch (inm->inm_state) {
+               case IGMP_NOT_MEMBER:
+               case IGMP_SILENT_MEMBER:
+                       break;
+               case IGMP_REPORTING_MEMBER:
+               case IGMP_IDLE_MEMBER:
+               case IGMP_LAZY_MEMBER:
+               case IGMP_SLEEPING_MEMBER:
+               case IGMP_AWAKENING_MEMBER:
+                       inm->inm_state = IGMP_REPORTING_MEMBER;
+                       IGI_LOCK(igi);
+                       retval = igmp_v3_enqueue_group_record(&igi->igi_gq,
+                           inm, 0, 0, 0);
+                       IGI_UNLOCK(igi);
+                       IGMP_PRINTF(("%s: enqueue record = %d\n",
+                           __func__, retval));
+                       break;
+               case IGMP_G_QUERY_PENDING_MEMBER:
+               case IGMP_SG_QUERY_PENDING_MEMBER:
+               case IGMP_LEAVING_MEMBER:
+                       break;
+               }
+next:
+               INM_UNLOCK(inm);
+               IN_NEXT_MULTI(step, inm);
+       }
+       in_multihead_lock_done();
+
+       IGI_LOCK(igi);
+       loop = (igi->igi_flags & IGIF_LOOPBACK) ? 1 : 0;
+       igmp_dispatch_queue(igi, &igi->igi_gq, IGMP_MAX_RESPONSE_BURST,
+           loop);
+       IGI_LOCK_ASSERT_HELD(igi);
+       /*
+        * Slew transmission of bursts over 1 second intervals.
+        */
+       if (igi->igi_gq.ifq_head != NULL) {
+               igi->igi_v3_timer = 1 + IGMP_RANDOM_DELAY(
+                   IGMP_RESPONSE_BURST_INTERVAL);
+       }
+
+       return (igi->igi_v3_timer);
+}
+
+/*
+ * Transmit the next pending IGMP message in the output queue.
+ *
+ * Must not be called with inm_lock or igi_lock held.
+ */
+static void
+igmp_sendpkt(struct mbuf *m)
+{
+       struct ip_moptions      *imo;
+       struct mbuf             *ipopts, *m0;
+       int                     error;
+       struct route            ro;
+       struct ifnet            *ifp;
+
+       IGMP_PRINTF(("%s: transmit 0x%llx\n", __func__,
+           (uint64_t)VM_KERNEL_ADDRPERM(m)));
+
+       ifp = igmp_restore_context(m);
+       /*
+        * Check if the ifnet is still attached.
+        */
+       if (ifp == NULL || !ifnet_is_attached(ifp, 0)) {
+               IGMP_PRINTF(("%s: dropped 0x%llx as ifp went away.\n",
+                   __func__, (uint64_t)VM_KERNEL_ADDRPERM(m)));
+               m_freem(m);
+               OSAddAtomic(1, &ipstat.ips_noroute);
+               return;
+       }
+
+       ipopts = igmp_sendra ? m_raopt : NULL;
+
+       imo = ip_allocmoptions(M_WAITOK);
+       if (imo == NULL) {
+               m_freem(m);
+               return;
+       }
+
+       imo->imo_multicast_ttl  = 1;
+       imo->imo_multicast_vif  = -1;
+       imo->imo_multicast_loop = 0;
+
+       /*
+        * If the user requested that IGMP traffic be explicitly
+        * redirected to the loopback interface (e.g. they are running a
+        * MANET interface and the routing protocol needs to see the
+        * updates), handle this now.
+        */
+       if (m->m_flags & M_IGMP_LOOP)
+               imo->imo_multicast_ifp = lo_ifp;
+       else
+               imo->imo_multicast_ifp = ifp;
+
+       if (m->m_flags & M_IGMPV2) {
+               m0 = m;
+       } else {
+               m0 = igmp_v3_encap_report(ifp, m);
+               if (m0 == NULL) {
+                       /*
+                        * If igmp_v3_encap_report() failed, then M_PREPEND()
+                        * already freed the original mbuf chain.
+                        * This means that we don't have to m_freem(m) here.
+                        */
+                       IGMP_PRINTF(("%s: dropped 0x%llx\n", __func__,
+                           (uint64_t)VM_KERNEL_ADDRPERM(m)));
+                       IMO_REMREF(imo);
+                       atomic_add_32(&ipstat.ips_odropped, 1);
+                       return;
+               }
+       }
+
+       igmp_scrub_context(m0);
+       m->m_flags &= ~(M_PROTOFLAGS | M_IGMP_LOOP);
+       m0->m_pkthdr.rcvif = lo_ifp;
+#ifdef MAC
+       mac_netinet_igmp_send(ifp, m0);
+#endif
+
+       if (ifp->if_eflags & IFEF_TXSTART) {
+               /*
+                * Use control service class if the interface supports
+                * transmit-start model.
+                */
+               (void) m_set_service_class(m0, MBUF_SC_CTL);
+       }
+       bzero(&ro, sizeof (ro));
+       error = ip_output(m0, ipopts, &ro, 0, imo, NULL);
+       ROUTE_RELEASE(&ro);
+
+       IMO_REMREF(imo);
+
+       if (error) {
+               IGMP_PRINTF(("%s: ip_output(0x%llx) = %d\n", __func__,
+                   (uint64_t)VM_KERNEL_ADDRPERM(m0), error));
+               return;
+       }
+
+       IGMPSTAT_INC(igps_snd_reports);
+       OIGMPSTAT_INC(igps_snd_reports);
+}
+/*
+ * Encapsulate an IGMPv3 report.
+ *
+ * The internal mbuf flag M_IGMPV3_HDR is used to indicate that the mbuf
+ * chain has already had its IP/IGMPv3 header prepended. In this case
+ * the function will not attempt to prepend; the lengths and checksums
+ * will however be re-computed.
+ *
+ * Returns a pointer to the new mbuf chain head, or NULL if the
+ * allocation failed.
+ */
+static struct mbuf *
+igmp_v3_encap_report(struct ifnet *ifp, struct mbuf *m)
+{
+       struct igmp_report      *igmp;
+       struct ip               *ip;
+       int                      hdrlen, igmpreclen;
+
+       VERIFY((m->m_flags & M_PKTHDR));
+
+       igmpreclen = m_length(m);
+       hdrlen = sizeof(struct ip) + sizeof(struct igmp_report);
+
+       if (m->m_flags & M_IGMPV3_HDR) {
+               igmpreclen -= hdrlen;
+       } else {
+               M_PREPEND(m, hdrlen, M_DONTWAIT, 1);
+               if (m == NULL)
+                       return (NULL);
+               m->m_flags |= M_IGMPV3_HDR;
+       }
+
+       IGMP_PRINTF(("%s: igmpreclen is %d\n", __func__, igmpreclen));
+
+       m->m_data += sizeof(struct ip);
+       m->m_len -= sizeof(struct ip);
+
+       igmp = mtod(m, struct igmp_report *);
+       igmp->ir_type = IGMP_v3_HOST_MEMBERSHIP_REPORT;
+       igmp->ir_rsv1 = 0;
+       igmp->ir_rsv2 = 0;
+       igmp->ir_numgrps = htons(m->m_pkthdr.vt_nrecs);
+       igmp->ir_cksum = 0;
+       igmp->ir_cksum = in_cksum(m, sizeof(struct igmp_report) + igmpreclen);
+       m->m_pkthdr.vt_nrecs = 0;
+
+       m->m_data -= sizeof(struct ip);
+       m->m_len += sizeof(struct ip);
+
+       ip = mtod(m, struct ip *);
+       ip->ip_tos = IPTOS_PREC_INTERNETCONTROL;
+       ip->ip_len = hdrlen + igmpreclen;
+       ip->ip_off = IP_DF;
+       ip->ip_p = IPPROTO_IGMP;
+       ip->ip_sum = 0;
+
+       ip->ip_src.s_addr = INADDR_ANY;
+
+       if (m->m_flags & M_IGMP_LOOP) {
+               struct in_ifaddr *ia;
+
+               IFP_TO_IA(ifp, ia);
+               if (ia != NULL) {
+                       IFA_LOCK(&ia->ia_ifa);
+                       ip->ip_src = ia->ia_addr.sin_addr;
+                       IFA_UNLOCK(&ia->ia_ifa);
+                       IFA_REMREF(&ia->ia_ifa);
+               }
+       }
+
+       ip->ip_dst.s_addr = htonl(INADDR_ALLRPTS_GROUP);
+
+       return (m);
+}
+
+#ifdef IGMP_DEBUG
+static const char *
+igmp_rec_type_to_str(const int type)
+{
+       switch (type) {
+               case IGMP_CHANGE_TO_EXCLUDE_MODE:
+                       return "TO_EX";
+               case IGMP_CHANGE_TO_INCLUDE_MODE:
+                       return "TO_IN";
+               case IGMP_MODE_IS_EXCLUDE:
+                       return "MODE_EX";
+               case IGMP_MODE_IS_INCLUDE:
+                       return "MODE_IN";
+               case IGMP_ALLOW_NEW_SOURCES:
+                       return "ALLOW_NEW";
+               case IGMP_BLOCK_OLD_SOURCES:
+                       return "BLOCK_OLD";
+               default:
+                       break;
+       }
+       return "unknown";
+}
+#endif
+
+void
+igmp_init(struct protosw *pp, struct domain *dp)
+{
+#pragma unused(dp)
+       static int igmp_initialized = 0;
+
+       VERIFY((pp->pr_flags & (PR_INITIALIZED|PR_ATTACHED)) == PR_ATTACHED);
+
+       if (igmp_initialized)
+               return;
+       igmp_initialized = 1;
+
+       IGMP_PRINTF(("%s: initializing\n", __func__));
+
+       igmp_timers_are_running = 0;
+
+       /* Setup lock group and attribute for igmp_mtx */
+       igmp_mtx_grp_attr = lck_grp_attr_alloc_init();
+       igmp_mtx_grp = lck_grp_alloc_init("igmp_mtx", igmp_mtx_grp_attr);
+       igmp_mtx_attr = lck_attr_alloc_init();
+       lck_mtx_init(&igmp_mtx, igmp_mtx_grp, igmp_mtx_attr);
+
+       LIST_INIT(&igi_head);
+       m_raopt = igmp_ra_alloc();
+
+       igi_size = sizeof (struct igmp_ifinfo);
+       igi_zone = zinit(igi_size, IGI_ZONE_MAX * igi_size,
+           0, IGI_ZONE_NAME);
+       if (igi_zone == NULL) {
+               panic("%s: failed allocating %s", __func__, IGI_ZONE_NAME);
+               /* NOTREACHED */
+       }
+       zone_change(igi_zone, Z_EXPAND, TRUE);
+       zone_change(igi_zone, Z_CALLERACCT, FALSE);
+}