Initial import

Code is based on FreeBSD 8.2 with USB support from Sebastian Huber
and Thomas Doerfler. Initial TCP/IP stack work is from Kevel Kirspel.

1 files changed, 2840 insertions, 0 deletions

diff --git a/rtems/freebsd/netinet6/in6_mcast.c b/rtems/freebsd/netinet6/in6_mcast.c
new file mode 100644
index 00000000..86c51f45
--- /dev/null
+++ b/rtems/freebsd/netinet6/in6_mcast.c
@@ -0,0 +1,2840 @@
+#include <rtems/freebsd/machine/rtems-bsd-config.h>
+
+/*
+ * Copyright (c) 2009 Bruce Simpson.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * IPv6 multicast socket, group, and socket option processing module.
+ * Normative references: RFC 2292, RFC 3492, RFC 3542, RFC 3678, RFC 3810.
+ */
+
+#include <rtems/freebsd/sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <rtems/freebsd/local/opt_inet6.h>
+
+#include <rtems/freebsd/sys/param.h>
+#include <rtems/freebsd/sys/systm.h>
+#include <rtems/freebsd/sys/kernel.h>
+#include <rtems/freebsd/sys/malloc.h>
+#include <rtems/freebsd/sys/mbuf.h>
+#include <rtems/freebsd/sys/protosw.h>
+#include <rtems/freebsd/sys/socket.h>
+#include <rtems/freebsd/sys/socketvar.h>
+#include <rtems/freebsd/sys/protosw.h>
+#include <rtems/freebsd/sys/sysctl.h>
+#include <rtems/freebsd/sys/priv.h>
+#include <rtems/freebsd/sys/ktr.h>
+#include <rtems/freebsd/sys/tree.h>
+
+#include <rtems/freebsd/net/if.h>
+#include <rtems/freebsd/net/if_dl.h>
+#include <rtems/freebsd/net/route.h>
+#include <rtems/freebsd/net/vnet.h>
+
+#include <rtems/freebsd/netinet/in.h>
+#include <rtems/freebsd/netinet/in_var.h>
+#include <rtems/freebsd/netinet6/in6_var.h>
+#include <rtems/freebsd/netinet/ip6.h>
+#include <rtems/freebsd/netinet/icmp6.h>
+#include <rtems/freebsd/netinet6/ip6_var.h>
+#include <rtems/freebsd/netinet/in_pcb.h>
+#include <rtems/freebsd/netinet/tcp_var.h>
+#include <rtems/freebsd/netinet6/nd6.h>
+#include <rtems/freebsd/netinet6/mld6_var.h>
+#include <rtems/freebsd/netinet6/scope6_var.h>
+
+#ifndef KTR_MLD
+#define KTR_MLD KTR_INET6
+#endif
+
+#ifndef __SOCKUNION_DECLARED
+union sockunion {
+	struct sockaddr_storage	ss;
+	struct sockaddr		sa;
+	struct sockaddr_dl	sdl;
+	struct sockaddr_in6	sin6;
+};
+typedef union sockunion sockunion_t;
+#define __SOCKUNION_DECLARED
+#endif /* __SOCKUNION_DECLARED */
+
+static MALLOC_DEFINE(M_IN6MFILTER, "in6_mfilter",
+    "IPv6 multicast PCB-layer source filter");
+static MALLOC_DEFINE(M_IP6MADDR, "in6_multi", "IPv6 multicast group");
+static MALLOC_DEFINE(M_IP6MOPTS, "ip6_moptions", "IPv6 multicast options");
+static MALLOC_DEFINE(M_IP6MSOURCE, "ip6_msource",
+    "IPv6 multicast MLD-layer source filter");
+
+RB_GENERATE(ip6_msource_tree, ip6_msource, im6s_link, ip6_msource_cmp);
+
+/*
+ * Locking:
+ * - Lock order is: Giant, INP_WLOCK, IN6_MULTI_LOCK, MLD_LOCK, IF_ADDR_LOCK.
+ * - The IF_ADDR_LOCK is implicitly taken by in6m_lookup() earlier, however
+ *   it can be taken by code in net/if.c also.
+ * - ip6_moptions and in6_mfilter are covered by the INP_WLOCK.
+ *
+ * struct in6_multi is covered by IN6_MULTI_LOCK. There isn't strictly
+ * any need for in6_multi itself to be virtualized -- it is bound to an ifp
+ * anyway no matter what happens.
+ */
+struct mtx in6_multi_mtx;
+MTX_SYSINIT(in6_multi_mtx, &in6_multi_mtx, "in6_multi_mtx", MTX_DEF);
+
+static void	im6f_commit(struct in6_mfilter *);
+static int	im6f_get_source(struct in6_mfilter *imf,
+		    const struct sockaddr_in6 *psin,
+		    struct in6_msource **);
+static struct in6_msource *
+		im6f_graft(struct in6_mfilter *, const uint8_t,
+		    const struct sockaddr_in6 *);
+static void	im6f_leave(struct in6_mfilter *);
+static int	im6f_prune(struct in6_mfilter *, const struct sockaddr_in6 *);
+static void	im6f_purge(struct in6_mfilter *);
+static void	im6f_rollback(struct in6_mfilter *);
+static void	im6f_reap(struct in6_mfilter *);
+static int	im6o_grow(struct ip6_moptions *);
+static size_t	im6o_match_group(const struct ip6_moptions *,
+		    const struct ifnet *, const struct sockaddr *);
+static struct in6_msource *
+		im6o_match_source(const struct ip6_moptions *, const size_t,
+		    const struct sockaddr *);
+static void	im6s_merge(struct ip6_msource *ims,
+		    const struct in6_msource *lims, const int rollback);
+static int	in6_mc_get(struct ifnet *, const struct in6_addr *,
+		    struct in6_multi **);
+static int	in6m_get_source(struct in6_multi *inm,
+		    const struct in6_addr *addr, const int noalloc,
+		    struct ip6_msource **pims);
+static int	in6m_is_ifp_detached(const struct in6_multi *);
+static int	in6m_merge(struct in6_multi *, /*const*/ struct in6_mfilter *);
+static void	in6m_purge(struct in6_multi *);
+static void	in6m_reap(struct in6_multi *);
+static struct ip6_moptions *
+		in6p_findmoptions(struct inpcb *);
+static int	in6p_get_source_filters(struct inpcb *, struct sockopt *);
+static int	in6p_join_group(struct inpcb *, struct sockopt *);
+static int	in6p_leave_group(struct inpcb *, struct sockopt *);
+static struct ifnet *
+		in6p_lookup_mcast_ifp(const struct inpcb *,
+		    const struct sockaddr_in6 *);
+static int	in6p_block_unblock_source(struct inpcb *, struct sockopt *);
+static int	in6p_set_multicast_if(struct inpcb *, struct sockopt *);
+static int	in6p_set_source_filters(struct inpcb *, struct sockopt *);
+static int	sysctl_ip6_mcast_filters(SYSCTL_HANDLER_ARGS);
+
+SYSCTL_DECL(_net_inet6_ip6);	/* XXX Not in any common header. */
+
+SYSCTL_NODE(_net_inet6_ip6, OID_AUTO, mcast, CTLFLAG_RW, 0, "IPv6 multicast");
+
+static u_long in6_mcast_maxgrpsrc = IPV6_MAX_GROUP_SRC_FILTER;
+SYSCTL_ULONG(_net_inet6_ip6_mcast, OID_AUTO, maxgrpsrc,
+    CTLFLAG_RW | CTLFLAG_TUN, &in6_mcast_maxgrpsrc, 0,
+    "Max source filters per group");
+TUNABLE_ULONG("net.inet6.ip6.mcast.maxgrpsrc", &in6_mcast_maxgrpsrc);
+
+static u_long in6_mcast_maxsocksrc = IPV6_MAX_SOCK_SRC_FILTER;
+SYSCTL_ULONG(_net_inet6_ip6_mcast, OID_AUTO, maxsocksrc,
+    CTLFLAG_RW | CTLFLAG_TUN, &in6_mcast_maxsocksrc, 0,
+    "Max source filters per socket");
+TUNABLE_ULONG("net.inet6.ip6.mcast.maxsocksrc", &in6_mcast_maxsocksrc);
+
+/* TODO Virtualize this switch. */
+int in6_mcast_loop = IPV6_DEFAULT_MULTICAST_LOOP;
+SYSCTL_INT(_net_inet6_ip6_mcast, OID_AUTO, loop, CTLFLAG_RW | CTLFLAG_TUN,
+    &in6_mcast_loop, 0, "Loopback multicast datagrams by default");
+TUNABLE_INT("net.inet6.ip6.mcast.loop", &in6_mcast_loop);
+
+SYSCTL_NODE(_net_inet6_ip6_mcast, OID_AUTO, filters,
+    CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_ip6_mcast_filters,
+    "Per-interface stack-wide source filters");
+
+/*
+ * Inline function which wraps assertions for a valid ifp.
+ * The ifnet layer will set the ifma's ifp pointer to NULL if the ifp
+ * is detached.
+ */
+static int __inline
+in6m_is_ifp_detached(const struct in6_multi *inm)
+{
+	struct ifnet *ifp;
+
+	KASSERT(inm->in6m_ifma != NULL, ("%s: no ifma", __func__));
+	ifp = inm->in6m_ifma->ifma_ifp;
+	if (ifp != NULL) {
+		/*
+		 * Sanity check that network-layer notion of ifp is the
+		 * same as that of link-layer.
+		 */
+		KASSERT(inm->in6m_ifp == ifp, ("%s: bad ifp", __func__));
+	}
+
+	return (ifp == NULL);
+}
+
+/*
+ * Initialize an in6_mfilter structure to a known state at t0, t1
+ * with an empty source filter list.
+ */
+static __inline void
+im6f_init(struct in6_mfilter *imf, const int st0, const int st1)
+{
+	memset(imf, 0, sizeof(struct in6_mfilter));
+	RB_INIT(&imf->im6f_sources);
+	imf->im6f_st[0] = st0;
+	imf->im6f_st[1] = st1;
+}
+
+/*
+ * Resize the ip6_moptions vector to the next power-of-two minus 1.
+ * May be called with locks held; do not sleep.
+ */
+static int
+im6o_grow(struct ip6_moptions *imo)
+{
+	struct in6_multi	**nmships;
+	struct in6_multi	**omships;
+	struct in6_mfilter	 *nmfilters;
+	struct in6_mfilter	 *omfilters;
+	size_t			  idx;
+	size_t			  newmax;
+	size_t			  oldmax;
+
+	nmships = NULL;
+	nmfilters = NULL;
+	omships = imo->im6o_membership;
+	omfilters = imo->im6o_mfilters;
+	oldmax = imo->im6o_max_memberships;
+	newmax = ((oldmax + 1) * 2) - 1;
+
+	if (newmax <= IPV6_MAX_MEMBERSHIPS) {
+		nmships = (struct in6_multi **)realloc(omships,
+		    sizeof(struct in6_multi *) * newmax, M_IP6MOPTS, M_NOWAIT);
+		nmfilters = (struct in6_mfilter *)realloc(omfilters,
+		    sizeof(struct in6_mfilter) * newmax, M_IN6MFILTER,
+		    M_NOWAIT);
+		if (nmships != NULL && nmfilters != NULL) {
+			/* Initialize newly allocated source filter heads. */
+			for (idx = oldmax; idx < newmax; idx++) {
+				im6f_init(&nmfilters[idx], MCAST_UNDEFINED,
+				    MCAST_EXCLUDE);
+			}
+			imo->im6o_max_memberships = newmax;
+			imo->im6o_membership = nmships;
+			imo->im6o_mfilters = nmfilters;
+		}
+	}
+
+	if (nmships == NULL || nmfilters == NULL) {
+		if (nmships != NULL)
+			free(nmships, M_IP6MOPTS);
+		if (nmfilters != NULL)
+			free(nmfilters, M_IN6MFILTER);
+		return (ETOOMANYREFS);
+	}
+
+	return (0);
+}
+
+/*
+ * Find an IPv6 multicast group entry for this ip6_moptions instance
+ * which matches the specified group, and optionally an interface.
+ * Return its index into the array, or -1 if not found.
+ */
+static size_t
+im6o_match_group(const struct ip6_moptions *imo, const struct ifnet *ifp,
+    const struct sockaddr *group)
+{
+	const struct sockaddr_in6 *gsin6;
+	struct in6_multi	**pinm;
+	int		  idx;
+	int		  nmships;
+
+	gsin6 = (const struct sockaddr_in6 *)group;
+
+	/* The im6o_membership array may be lazy allocated. */
+	if (imo->im6o_membership == NULL || imo->im6o_num_memberships == 0)
+		return (-1);
+
+	nmships = imo->im6o_num_memberships;
+	pinm = &imo->im6o_membership[0];
+	for (idx = 0; idx < nmships; idx++, pinm++) {
+		if (*pinm == NULL)
+			continue;
+		if ((ifp == NULL || ((*pinm)->in6m_ifp == ifp)) &&
+		    IN6_ARE_ADDR_EQUAL(&(*pinm)->in6m_addr,
+		    &gsin6->sin6_addr)) {
+			break;
+		}
+	}
+	if (idx >= nmships)
+		idx = -1;
+
+	return (idx);
+}
+
+/*
+ * Find an IPv6 multicast source entry for this imo which matches
+ * the given group index for this socket, and source address.
+ *
+ * XXX TODO: The scope ID, if present in src, is stripped before
+ * any comparison. We SHOULD enforce scope/zone checks where the source
+ * filter entry has a link scope.
+ *
+ * NOTE: This does not check if the entry is in-mode, merely if
+ * it exists, which may not be the desired behaviour.
+ */
+static struct in6_msource *
+im6o_match_source(const struct ip6_moptions *imo, const size_t gidx,
+    const struct sockaddr *src)
+{
+	struct ip6_msource	 find;
+	struct in6_mfilter	*imf;
+	struct ip6_msource	*ims;
+	const sockunion_t	*psa;
+
+	KASSERT(src->sa_family == AF_INET6, ("%s: !AF_INET6", __func__));
+	KASSERT(gidx != -1 && gidx < imo->im6o_num_memberships,
+	    ("%s: invalid index %d\n", __func__, (int)gidx));
+
+	/* The im6o_mfilters array may be lazy allocated. */
+	if (imo->im6o_mfilters == NULL)
+		return (NULL);
+	imf = &imo->im6o_mfilters[gidx];
+
+	psa = (const sockunion_t *)src;
+	find.im6s_addr = psa->sin6.sin6_addr;
+	in6_clearscope(&find.im6s_addr);		/* XXX */
+	ims = RB_FIND(ip6_msource_tree, &imf->im6f_sources, &find);
+
+	return ((struct in6_msource *)ims);
+}
+
+/*
+ * Perform filtering for multicast datagrams on a socket by group and source.
+ *
+ * Returns 0 if a datagram should be allowed through, or various error codes
+ * if the socket was not a member of the group, or the source was muted, etc.
+ */
+int
+im6o_mc_filter(const struct ip6_moptions *imo, const struct ifnet *ifp,
+    const struct sockaddr *group, const struct sockaddr *src)
+{
+	size_t gidx;
+	struct in6_msource *ims;
+	int mode;
+
+	KASSERT(ifp != NULL, ("%s: null ifp", __func__));
+
+	gidx = im6o_match_group(imo, ifp, group);
+	if (gidx == -1)
+		return (MCAST_NOTGMEMBER);
+
+	/*
+	 * Check if the source was included in an (S,G) join.
+	 * Allow reception on exclusive memberships by default,
+	 * reject reception on inclusive memberships by default.
+	 * Exclude source only if an in-mode exclude filter exists.
+	 * Include source only if an in-mode include filter exists.
+	 * NOTE: We are comparing group state here at MLD t1 (now)
+	 * with socket-layer t0 (since last downcall).
+	 */
+	mode = imo->im6o_mfilters[gidx].im6f_st[1];
+	ims = im6o_match_source(imo, gidx, src);
+
+	if ((ims == NULL && mode == MCAST_INCLUDE) ||
+	    (ims != NULL && ims->im6sl_st[0] != mode))
+		return (MCAST_NOTSMEMBER);
+
+	return (MCAST_PASS);
+}
+
+/*
+ * Find and return a reference to an in6_multi record for (ifp, group),
+ * and bump its reference count.
+ * If one does not exist, try to allocate it, and update link-layer multicast
+ * filters on ifp to listen for group.
+ * Assumes the IN6_MULTI lock is held across the call.
+ * Return 0 if successful, otherwise return an appropriate error code.
+ */
+static int
+in6_mc_get(struct ifnet *ifp, const struct in6_addr *group,
+    struct in6_multi **pinm)
+{
+	struct sockaddr_in6	 gsin6;
+	struct ifmultiaddr	*ifma;
+	struct in6_multi	*inm;
+	int			 error;
+
+	error = 0;
+
+	/*
+	 * XXX: Accesses to ifma_protospec must be covered by IF_ADDR_LOCK;
+	 * if_addmulti() takes this mutex itself, so we must drop and
+	 * re-acquire around the call.
+	 */
+	IN6_MULTI_LOCK_ASSERT();
+	IF_ADDR_LOCK(ifp);
+
+	inm = in6m_lookup_locked(ifp, group);
+	if (inm != NULL) {
+		/*
+		 * If we already joined this group, just bump the
+		 * refcount and return it.
+		 */
+		KASSERT(inm->in6m_refcount >= 1,
+		    ("%s: bad refcount %d", __func__, inm->in6m_refcount));
+		++inm->in6m_refcount;
+		*pinm = inm;
+		goto out_locked;
+	}
+
+	memset(&gsin6, 0, sizeof(gsin6));
+	gsin6.sin6_family = AF_INET6;
+	gsin6.sin6_len = sizeof(struct sockaddr_in6);
+	gsin6.sin6_addr = *group;
+
+	/*
+	 * Check if a link-layer group is already associated
+	 * with this network-layer group on the given ifnet.
+	 */
+	IF_ADDR_UNLOCK(ifp);
+	error = if_addmulti(ifp, (struct sockaddr *)&gsin6, &ifma);
+	if (error != 0)
+		return (error);
+	IF_ADDR_LOCK(ifp);
+
+	/*
+	 * If something other than netinet6 is occupying the link-layer
+	 * group, print a meaningful error message and back out of
+	 * the allocation.
+	 * Otherwise, bump the refcount on the existing network-layer
+	 * group association and return it.
+	 */
+	if (ifma->ifma_protospec != NULL) {
+		inm = (struct in6_multi *)ifma->ifma_protospec;
+#ifdef INVARIANTS
+		KASSERT(ifma->ifma_addr != NULL, ("%s: no ifma_addr",
+		    __func__));
+		KASSERT(ifma->ifma_addr->sa_family == AF_INET6,
+		    ("%s: ifma not AF_INET6", __func__));
+		KASSERT(inm != NULL, ("%s: no ifma_protospec", __func__));
+		if (inm->in6m_ifma != ifma || inm->in6m_ifp != ifp ||
+		    !IN6_ARE_ADDR_EQUAL(&inm->in6m_addr, group))
+			panic("%s: ifma %p is inconsistent with %p (%p)",
+			    __func__, ifma, inm, group);
+#endif
+		++inm->in6m_refcount;
+		*pinm = inm;
+		goto out_locked;
+	}
+
+	IF_ADDR_LOCK_ASSERT(ifp);
+
+	/*
+	 * A new in6_multi record is needed; allocate and initialize it.
+	 * We DO NOT perform an MLD join as the in6_ layer may need to
+	 * push an initial source list down to MLD to support SSM.
+	 *
+	 * The initial source filter state is INCLUDE, {} as per the RFC.
+	 * Pending state-changes per group are subject to a bounds check.
+	 */
+	inm = malloc(sizeof(*inm), M_IP6MADDR, M_NOWAIT | M_ZERO);
+	if (inm == NULL) {
+		if_delmulti_ifma(ifma);
+		error = ENOMEM;
+		goto out_locked;
+	}
+	inm->in6m_addr = *group;
+	inm->in6m_ifp = ifp;
+	inm->in6m_mli = MLD_IFINFO(ifp);
+	inm->in6m_ifma = ifma;
+	inm->in6m_refcount = 1;
+	inm->in6m_state = MLD_NOT_MEMBER;
+	IFQ_SET_MAXLEN(&inm->in6m_scq, MLD_MAX_STATE_CHANGES);
+
+	inm->in6m_st[0].iss_fmode = MCAST_UNDEFINED;
+	inm->in6m_st[1].iss_fmode = MCAST_UNDEFINED;
+	RB_INIT(&inm->in6m_srcs);
+
+	ifma->ifma_protospec = inm;
+	*pinm = inm;
+
+out_locked:
+	IF_ADDR_UNLOCK(ifp);
+	return (error);
+}
+
+/*
+ * Drop a reference to an in6_multi record.
+ *
+ * If the refcount drops to 0, free the in6_multi record and
+ * delete the underlying link-layer membership.
+ */
+void
+in6m_release_locked(struct in6_multi *inm)
+{
+	struct ifmultiaddr *ifma;
+
+	IN6_MULTI_LOCK_ASSERT();
+
+	CTR2(KTR_MLD, "%s: refcount is %d", __func__, inm->in6m_refcount);
+
+	if (--inm->in6m_refcount > 0) {
+		CTR2(KTR_MLD, "%s: refcount is now %d", __func__,
+		    inm->in6m_refcount);
+		return;
+	}
+
+	CTR2(KTR_MLD, "%s: freeing inm %p", __func__, inm);
+
+	ifma = inm->in6m_ifma;
+
+	/* XXX this access is not covered by IF_ADDR_LOCK */
+	CTR2(KTR_MLD, "%s: purging ifma %p", __func__, ifma);
+	KASSERT(ifma->ifma_protospec == inm,
+	    ("%s: ifma_protospec != inm", __func__));
+	ifma->ifma_protospec = NULL;
+
+	in6m_purge(inm);
+
+	free(inm, M_IP6MADDR);
+
+	if_delmulti_ifma(ifma);
+}
+
+/*
+ * Clear recorded source entries for a group.
+ * Used by the MLD code. Caller must hold the IN6_MULTI lock.
+ * FIXME: Should reap.
+ */
+void
+in6m_clear_recorded(struct in6_multi *inm)
+{
+	struct ip6_msource	*ims;
+
+	IN6_MULTI_LOCK_ASSERT();
+
+	RB_FOREACH(ims, ip6_msource_tree, &inm->in6m_srcs) {
+		if (ims->im6s_stp) {
+			ims->im6s_stp = 0;
+			--inm->in6m_st[1].iss_rec;
+		}
+	}
+	KASSERT(inm->in6m_st[1].iss_rec == 0,
+	    ("%s: iss_rec %d not 0", __func__, inm->in6m_st[1].iss_rec));
+}
+
+/*
+ * Record a source as pending for a Source-Group MLDv2 query.
+ * This lives here as it modifies the shared tree.
+ *
+ * inm is the group descriptor.
+ * naddr is the address of the source to record in network-byte order.
+ *
+ * If the net.inet6.mld.sgalloc sysctl is non-zero, we will
+ * lazy-allocate a source node in response to an SG query.
+ * Otherwise, no allocation is performed. This saves some memory
+ * with the trade-off that the source will not be reported to the
+ * router if joined in the window between the query response and
+ * the group actually being joined on the local host.
+ *
+ * VIMAGE: XXX: Currently the mld_sgalloc feature has been removed.
+ * This turns off the allocation of a recorded source entry if
+ * the group has not been joined.
+ *
+ * Return 0 if the source didn't exist or was already marked as recorded.
+ * Return 1 if the source was marked as recorded by this function.
+ * Return <0 if any error occured (negated errno code).
+ */
+int
+in6m_record_source(struct in6_multi *inm, const struct in6_addr *addr)
+{
+	struct ip6_msource	 find;
+	struct ip6_msource	*ims, *nims;
+
+	IN6_MULTI_LOCK_ASSERT();
+
+	find.im6s_addr = *addr;
+	ims = RB_FIND(ip6_msource_tree, &inm->in6m_srcs, &find);
+	if (ims && ims->im6s_stp)
+		return (0);
+	if (ims == NULL) {
+		if (inm->in6m_nsrc == in6_mcast_maxgrpsrc)
+			return (-ENOSPC);
+		nims = malloc(sizeof(struct ip6_msource), M_IP6MSOURCE,
+		    M_NOWAIT | M_ZERO);
+		if (nims == NULL)
+			return (-ENOMEM);
+		nims->im6s_addr = find.im6s_addr;
+		RB_INSERT(ip6_msource_tree, &inm->in6m_srcs, nims);
+		++inm->in6m_nsrc;
+		ims = nims;
+	}
+
+	/*
+	 * Mark the source as recorded and update the recorded
+	 * source count.
+	 */
+	++ims->im6s_stp;
+	++inm->in6m_st[1].iss_rec;
+
+	return (1);
+}
+
+/*
+ * Return a pointer to an in6_msource owned by an in6_mfilter,
+ * given its source address.
+ * Lazy-allocate if needed. If this is a new entry its filter state is
+ * undefined at t0.
+ *
+ * imf is the filter set being modified.
+ * addr is the source address.
+ *
+ * SMPng: May be called with locks held; malloc must not block.
+ */
+static int
+im6f_get_source(struct in6_mfilter *imf, const struct sockaddr_in6 *psin,
+    struct in6_msource **plims)
+{
+	struct ip6_msource	 find;
+	struct ip6_msource	*ims, *nims;
+	struct in6_msource	*lims;
+	int			 error;
+
+	error = 0;
+	ims = NULL;
+	lims = NULL;
+
+	find.im6s_addr = psin->sin6_addr;
+	ims = RB_FIND(ip6_msource_tree, &imf->im6f_sources, &find);
+	lims = (struct in6_msource *)ims;
+	if (lims == NULL) {
+		if (imf->im6f_nsrc == in6_mcast_maxsocksrc)
+			return (ENOSPC);
+		nims = malloc(sizeof(struct in6_msource), M_IN6MFILTER,
+		    M_NOWAIT | M_ZERO);
+		if (nims == NULL)
+			return (ENOMEM);
+		lims = (struct in6_msource *)nims;
+		lims->im6s_addr = find.im6s_addr;
+		lims->im6sl_st[0] = MCAST_UNDEFINED;
+		RB_INSERT(ip6_msource_tree, &imf->im6f_sources, nims);
+		++imf->im6f_nsrc;
+	}
+
+	*plims = lims;
+
+	return (error);
+}
+
+/*
+ * Graft a source entry into an existing socket-layer filter set,
+ * maintaining any required invariants and checking allocations.
+ *
+ * The source is marked as being in the new filter mode at t1.
+ *
+ * Return the pointer to the new node, otherwise return NULL.
+ */
+static struct in6_msource *
+im6f_graft(struct in6_mfilter *imf, const uint8_t st1,
+    const struct sockaddr_in6 *psin)
+{
+	struct ip6_msource	*nims;
+	struct in6_msource	*lims;
+
+	nims = malloc(sizeof(struct in6_msource), M_IN6MFILTER,
+	    M_NOWAIT | M_ZERO);
+	if (nims == NULL)
+		return (NULL);
+	lims = (struct in6_msource *)nims;
+	lims->im6s_addr = psin->sin6_addr;
+	lims->im6sl_st[0] = MCAST_UNDEFINED;
+	lims->im6sl_st[1] = st1;
+	RB_INSERT(ip6_msource_tree, &imf->im6f_sources, nims);
+	++imf->im6f_nsrc;
+
+	return (lims);
+}
+
+/*
+ * Prune a source entry from an existing socket-layer filter set,
+ * maintaining any required invariants and checking allocations.
+ *
+ * The source is marked as being left at t1, it is not freed.
+ *
+ * Return 0 if no error occurred, otherwise return an errno value.
+ */
+static int
+im6f_prune(struct in6_mfilter *imf, const struct sockaddr_in6 *psin)
+{
+	struct ip6_msource	 find;
+	struct ip6_msource	*ims;
+	struct in6_msource	*lims;
+
+	find.im6s_addr = psin->sin6_addr;
+	ims = RB_FIND(ip6_msource_tree, &imf->im6f_sources, &find);
+	if (ims == NULL)
+		return (ENOENT);
+	lims = (struct in6_msource *)ims;
+	lims->im6sl_st[1] = MCAST_UNDEFINED;
+	return (0);
+}
+
+/*
+ * Revert socket-layer filter set deltas at t1 to t0 state.
+ */
+static void
+im6f_rollback(struct in6_mfilter *imf)
+{
+	struct ip6_msource	*ims, *tims;
+	struct in6_msource	*lims;
+
+	RB_FOREACH_SAFE(ims, ip6_msource_tree, &imf->im6f_sources, tims) {
+		lims = (struct in6_msource *)ims;
+		if (lims->im6sl_st[0] == lims->im6sl_st[1]) {
+			/* no change at t1 */
+			continue;
+		} else if (lims->im6sl_st[0] != MCAST_UNDEFINED) {
+			/* revert change to existing source at t1 */
+			lims->im6sl_st[1] = lims->im6sl_st[0];
+		} else {
+			/* revert source added t1 */
+			CTR2(KTR_MLD, "%s: free ims %p", __func__, ims);
+			RB_REMOVE(ip6_msource_tree, &imf->im6f_sources, ims);
+			free(ims, M_IN6MFILTER);
+			imf->im6f_nsrc--;
+		}
+	}
+	imf->im6f_st[1] = imf->im6f_st[0];
+}
+
+/*
+ * Mark socket-layer filter set as INCLUDE {} at t1.
+ */
+static void
+im6f_leave(struct in6_mfilter *imf)
+{
+	struct ip6_msource	*ims;
+	struct in6_msource	*lims;
+
+	RB_FOREACH(ims, ip6_msource_tree, &imf->im6f_sources) {
+		lims = (struct in6_msource *)ims;
+		lims->im6sl_st[1] = MCAST_UNDEFINED;
+	}
+	imf->im6f_st[1] = MCAST_INCLUDE;
+}
+
+/*
+ * Mark socket-layer filter set deltas as committed.
+ */
+static void
+im6f_commit(struct in6_mfilter *imf)
+{
+	struct ip6_msource	*ims;
+	struct in6_msource	*lims;
+
+	RB_FOREACH(ims, ip6_msource_tree, &imf->im6f_sources) {
+		lims = (struct in6_msource *)ims;
+		lims->im6sl_st[0] = lims->im6sl_st[1];
+	}
+	imf->im6f_st[0] = imf->im6f_st[1];
+}
+
+/*
+ * Reap unreferenced sources from socket-layer filter set.
+ */
+static void
+im6f_reap(struct in6_mfilter *imf)
+{
+	struct ip6_msource	*ims, *tims;
+	struct in6_msource	*lims;
+
+	RB_FOREACH_SAFE(ims, ip6_msource_tree, &imf->im6f_sources, tims) {
+		lims = (struct in6_msource *)ims;
+		if ((lims->im6sl_st[0] == MCAST_UNDEFINED) &&
+		    (lims->im6sl_st[1] == MCAST_UNDEFINED)) {
+			CTR2(KTR_MLD, "%s: free lims %p", __func__, ims);
+			RB_REMOVE(ip6_msource_tree, &imf->im6f_sources, ims);
+			free(ims, M_IN6MFILTER);
+			imf->im6f_nsrc--;
+		}
+	}
+}
+
+/*
+ * Purge socket-layer filter set.
+ */
+static void
+im6f_purge(struct in6_mfilter *imf)
+{
+	struct ip6_msource	*ims, *tims;
+
+	RB_FOREACH_SAFE(ims, ip6_msource_tree, &imf->im6f_sources, tims) {
+		CTR2(KTR_MLD, "%s: free ims %p", __func__, ims);
+		RB_REMOVE(ip6_msource_tree, &imf->im6f_sources, ims);
+		free(ims, M_IN6MFILTER);
+		imf->im6f_nsrc--;
+	}
+	imf->im6f_st[0] = imf->im6f_st[1] = MCAST_UNDEFINED;
+	KASSERT(RB_EMPTY(&imf->im6f_sources),
+	    ("%s: im6f_sources not empty", __func__));
+}
+
+/*
+ * Look up a source filter entry for a multicast group.
+ *
+ * inm is the group descriptor to work with.
+ * addr is the IPv6 address to look up.
+ * noalloc may be non-zero to suppress allocation of sources.
+ * *pims will be set to the address of the retrieved or allocated source.
+ *
+ * SMPng: NOTE: may be called with locks held.
+ * Return 0 if successful, otherwise return a non-zero error code.
+ */
+static int
+in6m_get_source(struct in6_multi *inm, const struct in6_addr *addr,
+    const int noalloc, struct ip6_msource **pims)
+{
+	struct ip6_msource	 find;
+	struct ip6_msource	*ims, *nims;
+#ifdef KTR
+	char			 ip6tbuf[INET6_ADDRSTRLEN];
+#endif
+
+	find.im6s_addr = *addr;
+	ims = RB_FIND(ip6_msource_tree, &inm->in6m_srcs, &find);
+	if (ims == NULL && !noalloc) {
+		if (inm->in6m_nsrc == in6_mcast_maxgrpsrc)
+			return (ENOSPC);
+		nims = malloc(sizeof(struct ip6_msource), M_IP6MSOURCE,
+		    M_NOWAIT | M_ZERO);
+		if (nims == NULL)
+			return (ENOMEM);
+		nims->im6s_addr = *addr;
+		RB_INSERT(ip6_msource_tree, &inm->in6m_srcs, nims);
+		++inm->in6m_nsrc;
+		ims = nims;
+		CTR3(KTR_MLD, "%s: allocated %s as %p", __func__,
+		    ip6_sprintf(ip6tbuf, addr), ims);
+	}
+
+	*pims = ims;
+	return (0);
+}
+
+/*
+ * Merge socket-layer source into MLD-layer source.
+ * If rollback is non-zero, perform the inverse of the merge.
+ */
+static void
+im6s_merge(struct ip6_msource *ims, const struct in6_msource *lims,
+    const int rollback)
+{
+	int n = rollback ? -1 : 1;
+#ifdef KTR
+	char ip6tbuf[INET6_ADDRSTRLEN];
+
+	ip6_sprintf(ip6tbuf, &lims->im6s_addr);
+#endif
+
+	if (lims->im6sl_st[0] == MCAST_EXCLUDE) {
+		CTR3(KTR_MLD, "%s: t1 ex -= %d on %s", __func__, n, ip6tbuf);
+		ims->im6s_st[1].ex -= n;
+	} else if (lims->im6sl_st[0] == MCAST_INCLUDE) {
+		CTR3(KTR_MLD, "%s: t1 in -= %d on %s", __func__, n, ip6tbuf);
+		ims->im6s_st[1].in -= n;
+	}
+
+	if (lims->im6sl_st[1] == MCAST_EXCLUDE) {
+		CTR3(KTR_MLD, "%s: t1 ex += %d on %s", __func__, n, ip6tbuf);
+		ims->im6s_st[1].ex += n;
+	} else if (lims->im6sl_st[1] == MCAST_INCLUDE) {
+		CTR3(KTR_MLD, "%s: t1 in += %d on %s", __func__, n, ip6tbuf);
+		ims->im6s_st[1].in += n;
+	}
+}
+
+/*
+ * Atomically update the global in6_multi state, when a membership's
+ * filter list is being updated in any way.
+ *
+ * imf is the per-inpcb-membership group filter pointer.
+ * A fake imf may be passed for in-kernel consumers.
+ *
+ * XXX This is a candidate for a set-symmetric-difference style loop
+ * which would eliminate the repeated lookup from root of ims nodes,
+ * as they share the same key space.
+ *
+ * If any error occurred this function will back out of refcounts
+ * and return a non-zero value.
+ */
+static int
+in6m_merge(struct in6_multi *inm, /*const*/ struct in6_mfilter *imf)
+{
+	struct ip6_msource	*ims, *nims;
+	struct in6_msource	*lims;
+	int			 schanged, error;
+	int			 nsrc0, nsrc1;
+
+	schanged = 0;
+	error = 0;
+	nsrc1 = nsrc0 = 0;
+
+	/*
+	 * Update the source filters first, as this may fail.
+	 * Maintain count of in-mode filters at t0, t1. These are
+	 * used to work out if we transition into ASM mode or not.
+	 * Maintain a count of source filters whose state was
+	 * actually modified by this operation.
+	 */
+	RB_FOREACH(ims, ip6_msource_tree, &imf->im6f_sources) {
+		lims = (struct in6_msource *)ims;
+		if (lims->im6sl_st[0] == imf->im6f_st[0]) nsrc0++;
+		if (lims->im6sl_st[1] == imf->im6f_st[1]) nsrc1++;
+		if (lims->im6sl_st[0] == lims->im6sl_st[1]) continue;
+		error = in6m_get_source(inm, &lims->im6s_addr, 0, &nims);
+		++schanged;
+		if (error)
+			break;
+		im6s_merge(nims, lims, 0);
+	}
+	if (error) {
+		struct ip6_msource *bims;
+
+		RB_FOREACH_REVERSE_FROM(ims, ip6_msource_tree, nims) {
+			lims = (struct in6_msource *)ims;
+			if (lims->im6sl_st[0] == lims->im6sl_st[1])
+				continue;
+			(void)in6m_get_source(inm, &lims->im6s_addr, 1, &bims);
+			if (bims == NULL)
+				continue;
+			im6s_merge(bims, lims, 1);
+		}
+		goto out_reap;
+	}
+
+	CTR3(KTR_MLD, "%s: imf filters in-mode: %d at t0, %d at t1",
+	    __func__, nsrc0, nsrc1);
+
+	/* Handle transition between INCLUDE {n} and INCLUDE {} on socket. */
+	if (imf->im6f_st[0] == imf->im6f_st[1] &&
+	    imf->im6f_st[1] == MCAST_INCLUDE) {
+		if (nsrc1 == 0) {
+			CTR1(KTR_MLD, "%s: --in on inm at t1", __func__);
+			--inm->in6m_st[1].iss_in;
+		}
+	}
+
+	/* Handle filter mode transition on socket. */
+	if (imf->im6f_st[0] != imf->im6f_st[1]) {
+		CTR3(KTR_MLD, "%s: imf transition %d to %d",
+		    __func__, imf->im6f_st[0], imf->im6f_st[1]);
+
+		if (imf->im6f_st[0] == MCAST_EXCLUDE) {
+			CTR1(KTR_MLD, "%s: --ex on inm at t1", __func__);
+			--inm->in6m_st[1].iss_ex;
+		} else if (imf->im6f_st[0] == MCAST_INCLUDE) {
+			CTR1(KTR_MLD, "%s: --in on inm at t1", __func__);
+			--inm->in6m_st[1].iss_in;
+		}
+
+		if (imf->im6f_st[1] == MCAST_EXCLUDE) {
+			CTR1(KTR_MLD, "%s: ex++ on inm at t1", __func__);
+			inm->in6m_st[1].iss_ex++;
+		} else if (imf->im6f_st[1] == MCAST_INCLUDE && nsrc1 > 0) {
+			CTR1(KTR_MLD, "%s: in++ on inm at t1", __func__);
+			inm->in6m_st[1].iss_in++;
+		}
+	}
+
+	/*
+	 * Track inm filter state in terms of listener counts.
+	 * If there are any exclusive listeners, stack-wide
+	 * membership is exclusive.
+	 * Otherwise, if only inclusive listeners, stack-wide is inclusive.
+	 * If no listeners remain, state is undefined at t1,
+	 * and the MLD lifecycle for this group should finish.
+	 */
+	if (inm->in6m_st[1].iss_ex > 0) {
+		CTR1(KTR_MLD, "%s: transition to EX", __func__);
+		inm->in6m_st[1].iss_fmode = MCAST_EXCLUDE;
+	} else if (inm->in6m_st[1].iss_in > 0) {
+		CTR1(KTR_MLD, "%s: transition to IN", __func__);
+		inm->in6m_st[1].iss_fmode = MCAST_INCLUDE;
+	} else {
+		CTR1(KTR_MLD, "%s: transition to UNDEF", __func__);
+		inm->in6m_st[1].iss_fmode = MCAST_UNDEFINED;
+	}
+
+	/* Decrement ASM listener count on transition out of ASM mode. */
+	if (imf->im6f_st[0] == MCAST_EXCLUDE && nsrc0 == 0) {
+		if ((imf->im6f_st[1] != MCAST_EXCLUDE) ||
+		    (imf->im6f_st[1] == MCAST_EXCLUDE && nsrc1 > 0))
+			CTR1(KTR_MLD, "%s: --asm on inm at t1", __func__);
+			--inm->in6m_st[1].iss_asm;
+	}
+
+	/* Increment ASM listener count on transition to ASM mode. */
+	if (imf->im6f_st[1] == MCAST_EXCLUDE && nsrc1 == 0) {
+		CTR1(KTR_MLD, "%s: asm++ on inm at t1", __func__);
+		inm->in6m_st[1].iss_asm++;
+	}
+
+	CTR3(KTR_MLD, "%s: merged imf %p to inm %p", __func__, imf, inm);
+	in6m_print(inm);
+
+out_reap:
+	if (schanged > 0) {
+		CTR1(KTR_MLD, "%s: sources changed; reaping", __func__);
+		in6m_reap(inm);
+	}
+	return (error);
+}
+
+/*
+ * Mark an in6_multi's filter set deltas as committed.
+ * Called by MLD after a state change has been enqueued.
+ */
+void
+in6m_commit(struct in6_multi *inm)
+{
+	struct ip6_msource	*ims;
+
+	CTR2(KTR_MLD, "%s: commit inm %p", __func__, inm);
+	CTR1(KTR_MLD, "%s: pre commit:", __func__);
+	in6m_print(inm);
+
+	RB_FOREACH(ims, ip6_msource_tree, &inm->in6m_srcs) {
+		ims->im6s_st[0] = ims->im6s_st[1];
+	}
+	inm->in6m_st[0] = inm->in6m_st[1];
+}
+
+/*
+ * Reap unreferenced nodes from an in6_multi's filter set.
+ */
+static void
+in6m_reap(struct in6_multi *inm)
+{
+	struct ip6_msource	*ims, *tims;
+
+	RB_FOREACH_SAFE(ims, ip6_msource_tree, &inm->in6m_srcs, tims) {
+		if (ims->im6s_st[0].ex > 0 || ims->im6s_st[0].in > 0 ||
+		    ims->im6s_st[1].ex > 0 || ims->im6s_st[1].in > 0 ||
+		    ims->im6s_stp != 0)
+			continue;
+		CTR2(KTR_MLD, "%s: free ims %p", __func__, ims);
+		RB_REMOVE(ip6_msource_tree, &inm->in6m_srcs, ims);
+		free(ims, M_IP6MSOURCE);
+		inm->in6m_nsrc--;
+	}
+}
+
+/*
+ * Purge all source nodes from an in6_multi's filter set.
+ */
+static void
+in6m_purge(struct in6_multi *inm)
+{
+	struct ip6_msource	*ims, *tims;
+
+	RB_FOREACH_SAFE(ims, ip6_msource_tree, &inm->in6m_srcs, tims) {
+		CTR2(KTR_MLD, "%s: free ims %p", __func__, ims);
+		RB_REMOVE(ip6_msource_tree, &inm->in6m_srcs, ims);
+		free(ims, M_IP6MSOURCE);
+		inm->in6m_nsrc--;
+	}
+}
+
+/*
+ * Join a multicast address w/o sources.
+ * KAME compatibility entry point.
+ *
+ * SMPng: Assume no mc locks held by caller.
+ */
+struct in6_multi_mship *
+in6_joingroup(struct ifnet *ifp, struct in6_addr *mcaddr,
+    int *errorp, int delay)
+{
+	struct in6_multi_mship *imm;
+	int error;
+
+	imm = malloc(sizeof(*imm), M_IP6MADDR, M_NOWAIT);
+	if (imm == NULL) {
+		*errorp = ENOBUFS;
+		return (NULL);
+	}
+
+	delay = (delay * PR_FASTHZ) / hz;
+
+	error = in6_mc_join(ifp, mcaddr, NULL, &imm->i6mm_maddr, delay);
+	if (error) {
+		*errorp = error;
+		free(imm, M_IP6MADDR);
+		return (NULL);
+	}
+
+	return (imm);
+}
+
+/*
+ * Leave a multicast address w/o sources.
+ * KAME compatibility entry point.
+ *
+ * SMPng: Assume no mc locks held by caller.
+ */
+int
+in6_leavegroup(struct in6_multi_mship *imm)
+{
+
+	if (imm->i6mm_maddr != NULL)
+		in6_mc_leave(imm->i6mm_maddr, NULL);
+	free(imm,  M_IP6MADDR);
+	return 0;
+}
+
+/*
+ * Join a multicast group; unlocked entry point.
+ *
+ * SMPng: XXX: in6_mc_join() is called from in6_control() when upper
+ * locks are not held. Fortunately, ifp is unlikely to have been detached
+ * at this point, so we assume it's OK to recurse.
+ */
+int
+in6_mc_join(struct ifnet *ifp, const struct in6_addr *mcaddr,
+    /*const*/ struct in6_mfilter *imf, struct in6_multi **pinm,
+    const int delay)
+{
+	int error;
+
+	IN6_MULTI_LOCK();
+	error = in6_mc_join_locked(ifp, mcaddr, imf, pinm, delay);
+	IN6_MULTI_UNLOCK();
+
+	return (error);
+}
+
+/*
+ * Join a multicast group; real entry point.
+ *
+ * Only preserves atomicity at inm level.
+ * NOTE: imf argument cannot be const due to sys/tree.h limitations.
+ *
+ * If the MLD downcall fails, the group is not joined, and an error
+ * code is returned.
+ */
+int
+in6_mc_join_locked(struct ifnet *ifp, const struct in6_addr *mcaddr,
+    /*const*/ struct in6_mfilter *imf, struct in6_multi **pinm,
+    const int delay)
+{
+	struct in6_mfilter	 timf;
+	struct in6_multi	*inm;
+	int			 error;
+#ifdef KTR
+	char			 ip6tbuf[INET6_ADDRSTRLEN];
+#endif
+
+#ifdef INVARIANTS
+	/*
+	 * Sanity: Check scope zone ID was set for ifp, if and
+	 * only if group is scoped to an interface.
+	 */
+	KASSERT(IN6_IS_ADDR_MULTICAST(mcaddr),
+	    ("%s: not a multicast address", __func__));
+	if (IN6_IS_ADDR_MC_LINKLOCAL(mcaddr) ||
+	    IN6_IS_ADDR_MC_INTFACELOCAL(mcaddr)) {
+		KASSERT(mcaddr->s6_addr16[1] != 0,
+		    ("%s: scope zone ID not set", __func__));
+	}
+#endif
+
+	IN6_MULTI_LOCK_ASSERT();
+
+	CTR4(KTR_MLD, "%s: join %s on %p(%s))", __func__,
+	    ip6_sprintf(ip6tbuf, mcaddr), ifp, ifp->if_xname);
+
+	error = 0;
+	inm = NULL;
+
+	/*
+	 * If no imf was specified (i.e. kernel consumer),
+	 * fake one up and assume it is an ASM join.
+	 */
+	if (imf == NULL) {
+		im6f_init(&timf, MCAST_UNDEFINED, MCAST_EXCLUDE);
+		imf = &timf;
+	}
+
+	error = in6_mc_get(ifp, mcaddr, &inm);
+	if (error) {
+		CTR1(KTR_MLD, "%s: in6_mc_get() failure", __func__);
+		return (error);
+	}
+
+	CTR1(KTR_MLD, "%s: merge inm state", __func__);
+	error = in6m_merge(inm, imf);
+	if (error) {
+		CTR1(KTR_MLD, "%s: failed to merge inm state", __func__);
+		goto out_in6m_release;
+	}
+
+	CTR1(KTR_MLD, "%s: doing mld downcall", __func__);
+	error = mld_change_state(inm, delay);
+	if (error) {
+		CTR1(KTR_MLD, "%s: failed to update source", __func__);
+		goto out_in6m_release;
+	}
+
+out_in6m_release:
+	if (error) {
+		CTR2(KTR_MLD, "%s: dropping ref on %p", __func__, inm);
+		in6m_release_locked(inm);
+	} else {
+		*pinm = inm;
+	}
+
+	return (error);
+}
+
+/*
+ * Leave a multicast group; unlocked entry point.
+ */
+int
+in6_mc_leave(struct in6_multi *inm, /*const*/ struct in6_mfilter *imf)
+{
+	struct ifnet *ifp;
+	int error;
+
+	ifp = inm->in6m_ifp;
+
+	IN6_MULTI_LOCK();
+	error = in6_mc_leave_locked(inm, imf);
+	IN6_MULTI_UNLOCK();
+
+	return (error);
+}
+
+/*
+ * Leave a multicast group; real entry point.
+ * All source filters will be expunged.
+ *
+ * Only preserves atomicity at inm level.
+ *
+ * Holding the write lock for the INP which contains imf
+ * is highly advisable. We can't assert for it as imf does not
+ * contain a back-pointer to the owning inp.
+ *
+ * Note: This is not the same as in6m_release(*) as this function also
+ * makes a state change downcall into MLD.
+ */
+int
+in6_mc_leave_locked(struct in6_multi *inm, /*const*/ struct in6_mfilter *imf)
+{
+	struct in6_mfilter	 timf;
+	int			 error;
+#ifdef KTR
+	char			 ip6tbuf[INET6_ADDRSTRLEN];
+#endif
+
+	error = 0;
+
+	IN6_MULTI_LOCK_ASSERT();
+
+	CTR5(KTR_MLD, "%s: leave inm %p, %s/%s, imf %p", __func__,
+	    inm, ip6_sprintf(ip6tbuf, &inm->in6m_addr),
+	    (in6m_is_ifp_detached(inm) ? "null" : inm->in6m_ifp->if_xname),
+	    imf);
+
+	/*
+	 * If no imf was specified (i.e. kernel consumer),
+	 * fake one up and assume it is an ASM join.
+	 */
+	if (imf == NULL) {
+		im6f_init(&timf, MCAST_EXCLUDE, MCAST_UNDEFINED);
+		imf = &timf;
+	}
+
+	/*
+	 * Begin state merge transaction at MLD layer.
+	 *
+	 * As this particular invocation should not cause any memory
+	 * to be allocated, and there is no opportunity to roll back
+	 * the transaction, it MUST NOT fail.
+	 */
+	CTR1(KTR_MLD, "%s: merge inm state", __func__);
+	error = in6m_merge(inm, imf);
+	KASSERT(error == 0, ("%s: failed to merge inm state", __func__));
+
+	CTR1(KTR_MLD, "%s: doing mld downcall", __func__);
+	error = mld_change_state(inm, 0);
+	if (error)
+		CTR1(KTR_MLD, "%s: failed mld downcall", __func__);
+
+	CTR2(KTR_MLD, "%s: dropping ref on %p", __func__, inm);
+	in6m_release_locked(inm);
+
+	return (error);
+}
+
+/*
+ * Block or unblock an ASM multicast source on an inpcb.
+ * This implements the delta-based API described in RFC 3678.
+ *
+ * The delta-based API applies only to exclusive-mode memberships.
+ * An MLD downcall will be performed.
+ *
+ * SMPng: NOTE: Must take Giant as a join may create a new ifma.
+ *
+ * Return 0 if successful, otherwise return an appropriate error code.
+ */
+static int
+in6p_block_unblock_source(struct inpcb *inp, struct sockopt *sopt)
+{
+	struct group_source_req		 gsr;
+	sockunion_t			*gsa, *ssa;
+	struct ifnet			*ifp;
+	struct in6_mfilter		*imf;
+	struct ip6_moptions		*imo;
+	struct in6_msource		*ims;
+	struct in6_multi			*inm;
+	size_t				 idx;
+	uint16_t			 fmode;
+	int				 error, doblock;
+#ifdef KTR
+	char				 ip6tbuf[INET6_ADDRSTRLEN];
+#endif
+
+	ifp = NULL;
+	error = 0;
+	doblock = 0;
+
+	memset(&gsr, 0, sizeof(struct group_source_req));
+	gsa = (sockunion_t *)&gsr.gsr_group;
+	ssa = (sockunion_t *)&gsr.gsr_source;
+
+	switch (sopt->sopt_name) {
+	case MCAST_BLOCK_SOURCE:
+	case MCAST_UNBLOCK_SOURCE:
+		error = sooptcopyin(sopt, &gsr,
+		    sizeof(struct group_source_req),
+		    sizeof(struct group_source_req));
+		if (error)
+			return (error);
+
+		if (gsa->sin6.sin6_family != AF_INET6 ||
+		    gsa->sin6.sin6_len != sizeof(struct sockaddr_in6))
+			return (EINVAL);
+
+		if (ssa->sin6.sin6_family != AF_INET6 ||
+		    ssa->sin6.sin6_len != sizeof(struct sockaddr_in6))
+			return (EINVAL);
+
+		if (gsr.gsr_interface == 0 || V_if_index < gsr.gsr_interface)
+			return (EADDRNOTAVAIL);
+
+		ifp = ifnet_byindex(gsr.gsr_interface);
+
+		if (sopt->sopt_name == MCAST_BLOCK_SOURCE)
+			doblock = 1;
+		break;
+
+	default:
+		CTR2(KTR_MLD, "%s: unknown sopt_name %d",
+		    __func__, sopt->sopt_name);
+		return (EOPNOTSUPP);
+		break;
+	}
+
+	if (!IN6_IS_ADDR_MULTICAST(&gsa->sin6.sin6_addr))
+		return (EINVAL);
+
+	(void)in6_setscope(&gsa->sin6.sin6_addr, ifp, NULL);
+
+	/*
+	 * Check if we are actually a member of this group.
+	 */
+	imo = in6p_findmoptions(inp);
+	idx = im6o_match_group(imo, ifp, &gsa->sa);
+	if (idx == -1 || imo->im6o_mfilters == NULL) {
+		error = EADDRNOTAVAIL;
+		goto out_in6p_locked;
+	}
+
+	KASSERT(imo->im6o_mfilters != NULL,
+	    ("%s: im6o_mfilters not allocated", __func__));
+	imf = &imo->im6o_mfilters[idx];
+	inm = imo->im6o_membership[idx];
+
+	/*
+	 * Attempting to use the delta-based API on an
+	 * non exclusive-mode membership is an error.
+	 */
+	fmode = imf->im6f_st[0];
+	if (fmode != MCAST_EXCLUDE) {
+		error = EINVAL;
+		goto out_in6p_locked;
+	}
+
+	/*
+	 * Deal with error cases up-front:
+	 *  Asked to block, but already blocked; or
+	 *  Asked to unblock, but nothing to unblock.
+	 * If adding a new block entry, allocate it.
+	 */
+	ims = im6o_match_source(imo, idx, &ssa->sa);
+	if ((ims != NULL && doblock) || (ims == NULL && !doblock)) {
+		CTR3(KTR_MLD, "%s: source %s %spresent", __func__,
+		    ip6_sprintf(ip6tbuf, &ssa->sin6.sin6_addr),
+		    doblock ? "" : "not ");
+		error = EADDRNOTAVAIL;
+		goto out_in6p_locked;
+	}
+
+	INP_WLOCK_ASSERT(inp);
+
+	/*
+	 * Begin state merge transaction at socket layer.
+	 */
+	if (doblock) {
+		CTR2(KTR_MLD, "%s: %s source", __func__, "block");
+		ims = im6f_graft(imf, fmode, &ssa->sin6);
+		if (ims == NULL)
+			error = ENOMEM;
+	} else {
+		CTR2(KTR_MLD, "%s: %s source", __func__, "allow");
+		error = im6f_prune(imf, &ssa->sin6);
+	}
+
+	if (error) {
+		CTR1(KTR_MLD, "%s: merge imf state failed", __func__);
+		goto out_im6f_rollback;
+	}
+
+	/*
+	 * Begin state merge transaction at MLD layer.
+	 */
+	IN6_MULTI_LOCK();
+
+	CTR1(KTR_MLD, "%s: merge inm state", __func__);
+	error = in6m_merge(inm, imf);
+	if (error) {
+		CTR1(KTR_MLD, "%s: failed to merge inm state", __func__);
+		goto out_im6f_rollback;
+	}
+
+	CTR1(KTR_MLD, "%s: doing mld downcall", __func__);
+	error = mld_change_state(inm, 0);
+	if (error)
+		CTR1(KTR_MLD, "%s: failed mld downcall", __func__);
+
+	IN6_MULTI_UNLOCK();
+
+out_im6f_rollback:
+	if (error)
+		im6f_rollback(imf);
+	else
+		im6f_commit(imf);
+
+	im6f_reap(imf);
+
+out_in6p_locked:
+	INP_WUNLOCK(inp);
+	return (error);
+}
+
+/*
+ * Given an inpcb, return its multicast options structure pointer.  Accepts
+ * an unlocked inpcb pointer, but will return it locked.  May sleep.
+ *
+ * SMPng: NOTE: Potentially calls malloc(M_WAITOK) with Giant held.
+ * SMPng: NOTE: Returns with the INP write lock held.
+ */
+static struct ip6_moptions *
+in6p_findmoptions(struct inpcb *inp)
+{
+	struct ip6_moptions	 *imo;
+	struct in6_multi		**immp;
+	struct in6_mfilter	 *imfp;
+	size_t			  idx;
+
+	INP_WLOCK(inp);
+	if (inp->in6p_moptions != NULL)
+		return (inp->in6p_moptions);
+
+	INP_WUNLOCK(inp);
+
+	imo = malloc(sizeof(*imo), M_IP6MOPTS, M_WAITOK);
+	immp = malloc(sizeof(*immp) * IPV6_MIN_MEMBERSHIPS, M_IP6MOPTS,
+	    M_WAITOK | M_ZERO);
+	imfp = malloc(sizeof(struct in6_mfilter) * IPV6_MIN_MEMBERSHIPS,
+	    M_IN6MFILTER, M_WAITOK);
+
+	imo->im6o_multicast_ifp = NULL;
+	imo->im6o_multicast_hlim = V_ip6_defmcasthlim;
+	imo->im6o_multicast_loop = in6_mcast_loop;
+	imo->im6o_num_memberships = 0;
+	imo->im6o_max_memberships = IPV6_MIN_MEMBERSHIPS;
+	imo->im6o_membership = immp;
+
+	/* Initialize per-group source filters. */
+	for (idx = 0; idx < IPV6_MIN_MEMBERSHIPS; idx++)
+		im6f_init(&imfp[idx], MCAST_UNDEFINED, MCAST_EXCLUDE);
+	imo->im6o_mfilters = imfp;
+
+	INP_WLOCK(inp);
+	if (inp->in6p_moptions != NULL) {
+		free(imfp, M_IN6MFILTER);
+		free(immp, M_IP6MOPTS);
+		free(imo, M_IP6MOPTS);
+		return (inp->in6p_moptions);
+	}
+	inp->in6p_moptions = imo;
+	return (imo);
+}
+
+/*
+ * Discard the IPv6 multicast options (and source filters).
+ *
+ * SMPng: NOTE: assumes INP write lock is held.
+ */
+void
+ip6_freemoptions(struct ip6_moptions *imo)
+{
+	struct in6_mfilter	*imf;
+	size_t			 idx, nmships;
+
+	KASSERT(imo != NULL, ("%s: ip6_moptions is NULL", __func__));
+
+	nmships = imo->im6o_num_memberships;
+	for (idx = 0; idx < nmships; ++idx) {
+		imf = imo->im6o_mfilters ? &imo->im6o_mfilters[idx] : NULL;
+		if (imf)
+			im6f_leave(imf);
+		/* XXX this will thrash the lock(s) */
+		(void)in6_mc_leave(imo->im6o_membership[idx], imf);
+		if (imf)
+			im6f_purge(imf);
+	}
+
+	if (imo->im6o_mfilters)
+		free(imo->im6o_mfilters, M_IN6MFILTER);
+	free(imo->im6o_membership, M_IP6MOPTS);
+	free(imo, M_IP6MOPTS);
+}
+
+/*
+ * Atomically get source filters on a socket for an IPv6 multicast group.
+ * Called with INP lock held; returns with lock released.
+ */
+static int
+in6p_get_source_filters(struct inpcb *inp, struct sockopt *sopt)
+{
+	struct __msfilterreq	 msfr;
+	sockunion_t		*gsa;
+	struct ifnet		*ifp;
+	struct ip6_moptions	*imo;
+	struct in6_mfilter	*imf;
+	struct ip6_msource	*ims;
+	struct in6_msource	*lims;
+	struct sockaddr_in6	*psin;
+	struct sockaddr_storage	*ptss;
+	struct sockaddr_storage	*tss;
+	int			 error;
+	size_t			 idx, nsrcs, ncsrcs;
+
+	INP_WLOCK_ASSERT(inp);
+
+	imo = inp->in6p_moptions;
+	KASSERT(imo != NULL, ("%s: null ip6_moptions", __func__));
+
+	INP_WUNLOCK(inp);
+
+	error = sooptcopyin(sopt, &msfr, sizeof(struct __msfilterreq),
+	    sizeof(struct __msfilterreq));
+	if (error)
+		return (error);
+
+	if (msfr.msfr_group.ss_family != AF_INET6 ||
+	    msfr.msfr_group.ss_len != sizeof(struct sockaddr_in6))
+		return (EINVAL);
+
+	gsa = (sockunion_t *)&msfr.msfr_group;
+	if (!IN6_IS_ADDR_MULTICAST(&gsa->sin6.sin6_addr))
+		return (EINVAL);
+
+	if (msfr.msfr_ifindex == 0 || V_if_index < msfr.msfr_ifindex)
+		return (EADDRNOTAVAIL);
+	ifp = ifnet_byindex(msfr.msfr_ifindex);
+	if (ifp == NULL)
+		return (EADDRNOTAVAIL);
+	(void)in6_setscope(&gsa->sin6.sin6_addr, ifp, NULL);
+
+	INP_WLOCK(inp);
+
+	/*
+	 * Lookup group on the socket.
+	 */
+	idx = im6o_match_group(imo, ifp, &gsa->sa);
+	if (idx == -1 || imo->im6o_mfilters == NULL) {
+		INP_WUNLOCK(inp);
+		return (EADDRNOTAVAIL);
+	}
+	imf = &imo->im6o_mfilters[idx];
+
+	/*
+	 * Ignore memberships which are in limbo.
+	 */
+	if (imf->im6f_st[1] == MCAST_UNDEFINED) {
+		INP_WUNLOCK(inp);
+		return (EAGAIN);
+	}
+	msfr.msfr_fmode = imf->im6f_st[1];
+
+	/*
+	 * If the user specified a buffer, copy out the source filter
+	 * entries to userland gracefully.
+	 * We only copy out the number of entries which userland
+	 * has asked for, but we always tell userland how big the
+	 * buffer really needs to be.
+	 */
+	tss = NULL;
+	if (msfr.msfr_srcs != NULL && msfr.msfr_nsrcs > 0) {
+		tss = malloc(sizeof(struct sockaddr_storage) * msfr.msfr_nsrcs,
+		    M_TEMP, M_NOWAIT | M_ZERO);
+		if (tss == NULL) {
+			INP_WUNLOCK(inp);
+			return (ENOBUFS);
+		}
+	}
+
+	/*
+	 * Count number of sources in-mode at t0.
+	 * If buffer space exists and remains, copy out source entries.
+	 */
+	nsrcs = msfr.msfr_nsrcs;
+	ncsrcs = 0;
+	ptss = tss;
+	RB_FOREACH(ims, ip6_msource_tree, &imf->im6f_sources) {
+		lims = (struct in6_msource *)ims;
+		if (lims->im6sl_st[0] == MCAST_UNDEFINED ||
+		    lims->im6sl_st[0] != imf->im6f_st[0])
+			continue;
+		++ncsrcs;
+		if (tss != NULL && nsrcs > 0) {
+			psin = (struct sockaddr_in6 *)ptss;
+			psin->sin6_family = AF_INET6;
+			psin->sin6_len = sizeof(struct sockaddr_in6);
+			psin->sin6_addr = lims->im6s_addr;
+			psin->sin6_port = 0;
+			--nsrcs;
+			++ptss;
+		}
+	}
+
+	INP_WUNLOCK(inp);
+
+	if (tss != NULL) {
+		error = copyout(tss, msfr.msfr_srcs,
+		    sizeof(struct sockaddr_storage) * msfr.msfr_nsrcs);
+		free(tss, M_TEMP);
+		if (error)
+			return (error);
+	}
+
+	msfr.msfr_nsrcs = ncsrcs;
+	error = sooptcopyout(sopt, &msfr, sizeof(struct __msfilterreq));
+
+	return (error);
+}
+
+/*
+ * Return the IP multicast options in response to user getsockopt().
+ */
+int
+ip6_getmoptions(struct inpcb *inp, struct sockopt *sopt)
+{
+	struct ip6_moptions	*im6o;
+	int			 error;
+	u_int			 optval;
+
+	INP_WLOCK(inp);
+	im6o = inp->in6p_moptions;
+	/*
+	 * If socket is neither of type SOCK_RAW or SOCK_DGRAM,
+	 * or is a divert socket, reject it.
+	 */
+	if (inp->inp_socket->so_proto->pr_protocol == IPPROTO_DIVERT ||
+	    (inp->inp_socket->so_proto->pr_type != SOCK_RAW &&
+	    inp->inp_socket->so_proto->pr_type != SOCK_DGRAM)) {
+		INP_WUNLOCK(inp);
+		return (EOPNOTSUPP);
+	}
+
+	error = 0;
+	switch (sopt->sopt_name) {
+	case IPV6_MULTICAST_IF:
+		if (im6o == NULL || im6o->im6o_multicast_ifp == NULL) {
+			optval = 0;
+		} else {
+			optval = im6o->im6o_multicast_ifp->if_index;
+		}
+		INP_WUNLOCK(inp);
+		error = sooptcopyout(sopt, &optval, sizeof(u_int));
+		break;
+
+	case IPV6_MULTICAST_HOPS:
+		if (im6o == NULL)
+			optval = V_ip6_defmcasthlim;
+		else
+			optval = im6o->im6o_multicast_loop;
+		INP_WUNLOCK(inp);
+		error = sooptcopyout(sopt, &optval, sizeof(u_int));
+		break;
+
+	case IPV6_MULTICAST_LOOP:
+		if (im6o == NULL)
+			optval = in6_mcast_loop; /* XXX VIMAGE */
+		else
+			optval = im6o->im6o_multicast_loop;
+		INP_WUNLOCK(inp);
+		error = sooptcopyout(sopt, &optval, sizeof(u_int));
+		break;
+
+	case IPV6_MSFILTER:
+		if (im6o == NULL) {
+			error = EADDRNOTAVAIL;
+			INP_WUNLOCK(inp);
+		} else {
+			error = in6p_get_source_filters(inp, sopt);
+		}
+		break;
+
+	default:
+		INP_WUNLOCK(inp);
+		error = ENOPROTOOPT;
+		break;
+	}
+
+	INP_UNLOCK_ASSERT(inp);
+
+	return (error);
+}
+
+/*
+ * Look up the ifnet to use for a multicast group membership,
+ * given the address of an IPv6 group.
+ *
+ * This routine exists to support legacy IPv6 multicast applications.
+ *
+ * If inp is non-NULL, use this socket's current FIB number for any
+ * required FIB lookup. Look up the group address in the unicast FIB,
+ * and use its ifp; usually, this points to the default next-hop.
+ * If the FIB lookup fails, return NULL.
+ *
+ * FUTURE: Support multiple forwarding tables for IPv6.
+ *
+ * Returns NULL if no ifp could be found.
+ */
+static struct ifnet *
+in6p_lookup_mcast_ifp(const struct inpcb *in6p __unused,
+    const struct sockaddr_in6 *gsin6)
+{
+	struct route_in6	 ro6;
+	struct ifnet		*ifp;
+
+	KASSERT(in6p->inp_vflag & INP_IPV6,
+	    ("%s: not INP_IPV6 inpcb", __func__));
+	KASSERT(gsin6->sin6_family == AF_INET6,
+	    ("%s: not AF_INET6 group", __func__));
+	KASSERT(IN6_IS_ADDR_MULTICAST(&gsin6->sin6_addr),
+	    ("%s: not multicast", __func__));
+
+	ifp = NULL;
+	memset(&ro6, 0, sizeof(struct route_in6));
+	memcpy(&ro6.ro_dst, gsin6, sizeof(struct sockaddr_in6));
+#ifdef notyet
+	rtalloc_ign_fib(&ro6, 0, inp ? inp->inp_inc.inc_fibnum : 0);
+#else
+	rtalloc_ign((struct route *)&ro6, 0);
+#endif
+	if (ro6.ro_rt != NULL) {
+		ifp = ro6.ro_rt->rt_ifp;
+		KASSERT(ifp != NULL, ("%s: null ifp", __func__));
+		RTFREE(ro6.ro_rt);
+	}
+
+	return (ifp);
+}
+
+/*
+ * Join an IPv6 multicast group, possibly with a source.
+ *
+ * FIXME: The KAME use of the unspecified address (::)
+ * to join *all* multicast groups is currently unsupported.
+ */
+static int
+in6p_join_group(struct inpcb *inp, struct sockopt *sopt)
+{
+	struct group_source_req		 gsr;
+	sockunion_t			*gsa, *ssa;
+	struct ifnet			*ifp;
+	struct in6_mfilter		*imf;
+	struct ip6_moptions		*imo;
+	struct in6_multi		*inm;
+	struct in6_msource		*lims;
+	size_t				 idx;
+	int				 error, is_new;
+
+	ifp = NULL;
+	imf = NULL;
+	lims = NULL;
+	error = 0;
+	is_new = 0;
+
+	memset(&gsr, 0, sizeof(struct group_source_req));
+	gsa = (sockunion_t *)&gsr.gsr_group;
+	gsa->ss.ss_family = AF_UNSPEC;
+	ssa = (sockunion_t *)&gsr.gsr_source;
+	ssa->ss.ss_family = AF_UNSPEC;
+
+	/*
+	 * Chew everything into struct group_source_req.
+	 * Overwrite the port field if present, as the sockaddr
+	 * being copied in may be matched with a binary comparison.
+	 * Ignore passed-in scope ID.
+	 */
+	switch (sopt->sopt_name) {
+	case IPV6_JOIN_GROUP: {
+		struct ipv6_mreq mreq;
+
+		error = sooptcopyin(sopt, &mreq, sizeof(struct ipv6_mreq),
+		    sizeof(struct ipv6_mreq));
+		if (error)
+			return (error);
+
+		gsa->sin6.sin6_family = AF_INET6;
+		gsa->sin6.sin6_len = sizeof(struct sockaddr_in6);
+		gsa->sin6.sin6_addr = mreq.ipv6mr_multiaddr;
+
+		if (mreq.ipv6mr_interface == 0) {
+			ifp = in6p_lookup_mcast_ifp(inp, &gsa->sin6);
+		} else {
+			if (mreq.ipv6mr_interface < 0 ||
+			    V_if_index < mreq.ipv6mr_interface)
+				return (EADDRNOTAVAIL);
+			ifp = ifnet_byindex(mreq.ipv6mr_interface);
+		}
+		CTR3(KTR_MLD, "%s: ipv6mr_interface = %d, ifp = %p",
+		    __func__, mreq.ipv6mr_interface, ifp);
+	} break;
+
+	case MCAST_JOIN_GROUP:
+	case MCAST_JOIN_SOURCE_GROUP:
+		if (sopt->sopt_name == MCAST_JOIN_GROUP) {
+			error = sooptcopyin(sopt, &gsr,
+			    sizeof(struct group_req),
+			    sizeof(struct group_req));
+		} else if (sopt->sopt_name == MCAST_JOIN_SOURCE_GROUP) {
+			error = sooptcopyin(sopt, &gsr,
+			    sizeof(struct group_source_req),
+			    sizeof(struct group_source_req));
+		}
+		if (error)
+			return (error);
+
+		if (gsa->sin6.sin6_family != AF_INET6 ||
+		    gsa->sin6.sin6_len != sizeof(struct sockaddr_in6))
+			return (EINVAL);
+
+		if (sopt->sopt_name == MCAST_JOIN_SOURCE_GROUP) {
+			if (ssa->sin6.sin6_family != AF_INET6 ||
+			    ssa->sin6.sin6_len != sizeof(struct sockaddr_in6))
+				return (EINVAL);
+			if (IN6_IS_ADDR_MULTICAST(&ssa->sin6.sin6_addr))
+				return (EINVAL);
+			/*
+			 * TODO: Validate embedded scope ID in source
+			 * list entry against passed-in ifp, if and only
+			 * if source list filter entry is iface or node local.
+			 */
+			in6_clearscope(&ssa->sin6.sin6_addr);
+			ssa->sin6.sin6_port = 0;
+			ssa->sin6.sin6_scope_id = 0;
+		}
+
+		if (gsr.gsr_interface == 0 || V_if_index < gsr.gsr_interface)
+			return (EADDRNOTAVAIL);
+		ifp = ifnet_byindex(gsr.gsr_interface);
+		break;
+
+	default:
+		CTR2(KTR_MLD, "%s: unknown sopt_name %d",
+		    __func__, sopt->sopt_name);
+		return (EOPNOTSUPP);
+		break;
+	}
+
+	if (!IN6_IS_ADDR_MULTICAST(&gsa->sin6.sin6_addr))
+		return (EINVAL);
+
+	if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0)
+		return (EADDRNOTAVAIL);
+
+	gsa->sin6.sin6_port = 0;
+	gsa->sin6.sin6_scope_id = 0;
+
+	/*
+	 * Always set the scope zone ID on memberships created from userland.
+	 * Use the passed-in ifp to do this.
+	 * XXX The in6_setscope() return value is meaningless.
+	 * XXX SCOPE6_LOCK() is taken by in6_setscope().
+	 */
+	(void)in6_setscope(&gsa->sin6.sin6_addr, ifp, NULL);
+
+	imo = in6p_findmoptions(inp);
+	idx = im6o_match_group(imo, ifp, &gsa->sa);
+	if (idx == -1) {
+		is_new = 1;
+	} else {
+		inm = imo->im6o_membership[idx];
+		imf = &imo->im6o_mfilters[idx];
+		if (ssa->ss.ss_family != AF_UNSPEC) {
+			/*
+			 * MCAST_JOIN_SOURCE_GROUP on an exclusive membership
+			 * is an error. On an existing inclusive membership,
+			 * it just adds the source to the filter list.
+			 */
+			if (imf->im6f_st[1] != MCAST_INCLUDE) {
+				error = EINVAL;
+				goto out_in6p_locked;
+			}
+			/*
+			 * Throw out duplicates.
+			 *
+			 * XXX FIXME: This makes a naive assumption that
+			 * even if entries exist for *ssa in this imf,
+			 * they will be rejected as dupes, even if they
+			 * are not valid in the current mode (in-mode).
+			 *
+			 * in6_msource is transactioned just as for anything
+			 * else in SSM -- but note naive use of in6m_graft()
+			 * below for allocating new filter entries.
+			 *
+			 * This is only an issue if someone mixes the
+			 * full-state SSM API with the delta-based API,
+			 * which is discouraged in the relevant RFCs.
+			 */
+			lims = im6o_match_source(imo, idx, &ssa->sa);
+			if (lims != NULL /*&&
+			    lims->im6sl_st[1] == MCAST_INCLUDE*/) {
+				error = EADDRNOTAVAIL;
+				goto out_in6p_locked;
+			}
+		} else {
+			/*
+			 * MCAST_JOIN_GROUP alone, on any existing membership,
+			 * is rejected, to stop the same inpcb tying up
+			 * multiple refs to the in_multi.
+			 * On an existing inclusive membership, this is also
+			 * an error; if you want to change filter mode,
+			 * you must use the userland API setsourcefilter().
+			 * XXX We don't reject this for imf in UNDEFINED
+			 * state at t1, because allocation of a filter
+			 * is atomic with allocation of a membership.
+			 */
+			error = EINVAL;
+			goto out_in6p_locked;
+		}
+	}
+
+	/*
+	 * Begin state merge transaction at socket layer.
+	 */
+	INP_WLOCK_ASSERT(inp);
+
+	if (is_new) {
+		if (imo->im6o_num_memberships == imo->im6o_max_memberships) {
+			error = im6o_grow(imo);
+			if (error)
+				goto out_in6p_locked;
+		}
+		/*
+		 * Allocate the new slot upfront so we can deal with
+		 * grafting the new source filter in same code path
+		 * as for join-source on existing membership.
+		 */
+		idx = imo->im6o_num_memberships;
+		imo->im6o_membership[idx] = NULL;
+		imo->im6o_num_memberships++;
+		KASSERT(imo->im6o_mfilters != NULL,
+		    ("%s: im6f_mfilters vector was not allocated", __func__));
+		imf = &imo->im6o_mfilters[idx];
+		KASSERT(RB_EMPTY(&imf->im6f_sources),
+		    ("%s: im6f_sources not empty", __func__));
+	}
+
+	/*
+	 * Graft new source into filter list for this inpcb's
+	 * membership of the group. The in6_multi may not have
+	 * been allocated yet if this is a new membership, however,
+	 * the in_mfilter slot will be allocated and must be initialized.
+	 *
+	 * Note: Grafting of exclusive mode filters doesn't happen
+	 * in this path.
+	 * XXX: Should check for non-NULL lims (node exists but may
+	 * not be in-mode) for interop with full-state API.
+	 */
+	if (ssa->ss.ss_family != AF_UNSPEC) {
+		/* Membership starts in IN mode */
+		if (is_new) {
+			CTR1(KTR_MLD, "%s: new join w/source", __func__);
+			im6f_init(imf, MCAST_UNDEFINED, MCAST_INCLUDE);
+		} else {
+			CTR2(KTR_MLD, "%s: %s source", __func__, "allow");
+		}
+		lims = im6f_graft(imf, MCAST_INCLUDE, &ssa->sin6);
+		if (lims == NULL) {
+			CTR1(KTR_MLD, "%s: merge imf state failed",
+			    __func__);
+			error = ENOMEM;
+			goto out_im6o_free;
+		}
+	} else {
+		/* No address specified; Membership starts in EX mode */
+		if (is_new) {
+			CTR1(KTR_MLD, "%s: new join w/o source", __func__);
+			im6f_init(imf, MCAST_UNDEFINED, MCAST_EXCLUDE);
+		}
+	}
+
+	/*
+	 * Begin state merge transaction at MLD layer.
+	 */
+	IN6_MULTI_LOCK();
+
+	if (is_new) {
+		error = in6_mc_join_locked(ifp, &gsa->sin6.sin6_addr, imf,
+		    &inm, 0);
+		if (error)
+			goto out_im6o_free;
+		imo->im6o_membership[idx] = inm;
+	} else {
+		CTR1(KTR_MLD, "%s: merge inm state", __func__);
+		error = in6m_merge(inm, imf);
+		if (error) {
+			CTR1(KTR_MLD, "%s: failed to merge inm state",
+			    __func__);
+			goto out_im6f_rollback;
+		}
+		CTR1(KTR_MLD, "%s: doing mld downcall", __func__);
+		error = mld_change_state(inm, 0);
+		if (error) {
+			CTR1(KTR_MLD, "%s: failed mld downcall",
+			    __func__);
+			goto out_im6f_rollback;
+		}
+	}
+
+	IN6_MULTI_UNLOCK();
+
+out_im6f_rollback:
+	INP_WLOCK_ASSERT(inp);
+	if (error) {
+		im6f_rollback(imf);
+		if (is_new)
+			im6f_purge(imf);
+		else
+			im6f_reap(imf);
+	} else {
+		im6f_commit(imf);
+	}
+
+out_im6o_free:
+	if (error && is_new) {
+		imo->im6o_membership[idx] = NULL;
+		--imo->im6o_num_memberships;
+	}
+
+out_in6p_locked:
+	INP_WUNLOCK(inp);
+	return (error);
+}
+
+/*
+ * Leave an IPv6 multicast group on an inpcb, possibly with a source.
+ */
+static int
+in6p_leave_group(struct inpcb *inp, struct sockopt *sopt)
+{
+	struct ipv6_mreq		 mreq;
+	struct group_source_req		 gsr;
+	sockunion_t			*gsa, *ssa;
+	struct ifnet			*ifp;
+	struct in6_mfilter		*imf;
+	struct ip6_moptions		*imo;
+	struct in6_msource		*ims;
+	struct in6_multi		*inm;
+	uint32_t			 ifindex;
+	size_t				 idx;
+	int				 error, is_final;
+#ifdef KTR
+	char				 ip6tbuf[INET6_ADDRSTRLEN];
+#endif
+
+	ifp = NULL;
+	ifindex = 0;
+	error = 0;
+	is_final = 1;
+
+	memset(&gsr, 0, sizeof(struct group_source_req));
+	gsa = (sockunion_t *)&gsr.gsr_group;
+	gsa->ss.ss_family = AF_UNSPEC;
+	ssa = (sockunion_t *)&gsr.gsr_source;
+	ssa->ss.ss_family = AF_UNSPEC;
+
+	/*
+	 * Chew everything passed in up into a struct group_source_req
+	 * as that is easier to process.
+	 * Note: Any embedded scope ID in the multicast group passed
+	 * in by userland is ignored, the interface index is the recommended
+	 * mechanism to specify an interface; see below.
+	 */
+	switch (sopt->sopt_name) {
+	case IPV6_LEAVE_GROUP:
+		error = sooptcopyin(sopt, &mreq, sizeof(struct ipv6_mreq),
+		    sizeof(struct ipv6_mreq));
+		if (error)
+			return (error);
+		gsa->sin6.sin6_family = AF_INET6;
+		gsa->sin6.sin6_len = sizeof(struct sockaddr_in6);
+		gsa->sin6.sin6_addr = mreq.ipv6mr_multiaddr;
+		gsa->sin6.sin6_port = 0;
+		gsa->sin6.sin6_scope_id = 0;
+		ifindex = mreq.ipv6mr_interface;
+		break;
+
+	case MCAST_LEAVE_GROUP:
+	case MCAST_LEAVE_SOURCE_GROUP:
+		if (sopt->sopt_name == MCAST_LEAVE_GROUP) {
+			error = sooptcopyin(sopt, &gsr,
+			    sizeof(struct group_req),
+			    sizeof(struct group_req));
+		} else if (sopt->sopt_name == MCAST_LEAVE_SOURCE_GROUP) {
+			error = sooptcopyin(sopt, &gsr,
+			    sizeof(struct group_source_req),
+			    sizeof(struct group_source_req));
+		}
+		if (error)
+			return (error);
+
+		if (gsa->sin6.sin6_family != AF_INET6 ||
+		    gsa->sin6.sin6_len != sizeof(struct sockaddr_in6))
+			return (EINVAL);
+		if (sopt->sopt_name == MCAST_LEAVE_SOURCE_GROUP) {
+			if (ssa->sin6.sin6_family != AF_INET6 ||
+			    ssa->sin6.sin6_len != sizeof(struct sockaddr_in6))
+				return (EINVAL);
+			if (IN6_IS_ADDR_MULTICAST(&ssa->sin6.sin6_addr))
+				return (EINVAL);
+			/*
+			 * TODO: Validate embedded scope ID in source
+			 * list entry against passed-in ifp, if and only
+			 * if source list filter entry is iface or node local.
+			 */
+			in6_clearscope(&ssa->sin6.sin6_addr);
+		}
+		gsa->sin6.sin6_port = 0;
+		gsa->sin6.sin6_scope_id = 0;
+		ifindex = gsr.gsr_interface;
+		break;
+
+	default:
+		CTR2(KTR_MLD, "%s: unknown sopt_name %d",
+		    __func__, sopt->sopt_name);
+		return (EOPNOTSUPP);
+		break;
+	}
+
+	if (!IN6_IS_ADDR_MULTICAST(&gsa->sin6.sin6_addr))
+		return (EINVAL);
+
+	/*
+	 * Validate interface index if provided. If no interface index
+	 * was provided separately, attempt to look the membership up
+	 * from the default scope as a last resort to disambiguate
+	 * the membership we are being asked to leave.
+	 * XXX SCOPE6 lock potentially taken here.
+	 */
+	if (ifindex != 0) {
+		if (ifindex < 0 || V_if_index < ifindex)
+			return (EADDRNOTAVAIL);
+		ifp = ifnet_byindex(ifindex);
+		if (ifp == NULL)
+			return (EADDRNOTAVAIL);
+		(void)in6_setscope(&gsa->sin6.sin6_addr, ifp, NULL);
+	} else {
+		error = sa6_embedscope(&gsa->sin6, V_ip6_use_defzone);
+		if (error)
+			return (EADDRNOTAVAIL);
+		/*
+		 * Some badly behaved applications don't pass an ifindex
+		 * or a scope ID, which is an API violation. In this case,
+		 * perform a lookup as per a v6 join.
+		 *
+		 * XXX For now, stomp on zone ID for the corner case.
+		 * This is not the 'KAME way', but we need to see the ifp
+		 * directly until such time as this implementation is
+		 * refactored, assuming the scope IDs are the way to go.
+		 */
+		ifindex = ntohs(gsa->sin6.sin6_addr.s6_addr16[1]);
+		if (ifindex == 0) {
+			CTR2(KTR_MLD, "%s: warning: no ifindex, looking up "
+			    "ifp for group %s.", __func__,
+			    ip6_sprintf(ip6tbuf, &gsa->sin6.sin6_addr));
+			ifp = in6p_lookup_mcast_ifp(inp, &gsa->sin6);
+		} else {
+			ifp = ifnet_byindex(ifindex);
+		}
+		if (ifp == NULL)
+			return (EADDRNOTAVAIL);
+	}
+
+	CTR2(KTR_MLD, "%s: ifp = %p", __func__, ifp);
+	KASSERT(ifp != NULL, ("%s: ifp did not resolve", __func__));
+
+	/*
+	 * Find the membership in the membership array.
+	 */
+	imo = in6p_findmoptions(inp);
+	idx = im6o_match_group(imo, ifp, &gsa->sa);
+	if (idx == -1) {
+		error = EADDRNOTAVAIL;
+		goto out_in6p_locked;
+	}
+	inm = imo->im6o_membership[idx];
+	imf = &imo->im6o_mfilters[idx];
+
+	if (ssa->ss.ss_family != AF_UNSPEC)
+		is_final = 0;
+
+	/*
+	 * Begin state merge transaction at socket layer.
+	 */
+	INP_WLOCK_ASSERT(inp);
+
+	/*
+	 * If we were instructed only to leave a given source, do so.
+	 * MCAST_LEAVE_SOURCE_GROUP is only valid for inclusive memberships.
+	 */
+	if (is_final) {
+		im6f_leave(imf);
+	} else {
+		if (imf->im6f_st[0] == MCAST_EXCLUDE) {
+			error = EADDRNOTAVAIL;
+			goto out_in6p_locked;
+		}
+		ims = im6o_match_source(imo, idx, &ssa->sa);
+		if (ims == NULL) {
+			CTR3(KTR_MLD, "%s: source %p %spresent", __func__,
+			    ip6_sprintf(ip6tbuf, &ssa->sin6.sin6_addr),
+			    "not ");
+			error = EADDRNOTAVAIL;
+			goto out_in6p_locked;
+		}
+		CTR2(KTR_MLD, "%s: %s source", __func__, "block");
+		error = im6f_prune(imf, &ssa->sin6);
+		if (error) {
+			CTR1(KTR_MLD, "%s: merge imf state failed",
+			    __func__);
+			goto out_in6p_locked;
+		}
+	}
+
+	/*
+	 * Begin state merge transaction at MLD layer.
+	 */
+	IN6_MULTI_LOCK();
+
+	if (is_final) {
+		/*
+		 * Give up the multicast address record to which
+		 * the membership points.
+		 */
+		(void)in6_mc_leave_locked(inm, imf);
+	} else {
+		CTR1(KTR_MLD, "%s: merge inm state", __func__);
+		error = in6m_merge(inm, imf);
+		if (error) {
+			CTR1(KTR_MLD, "%s: failed to merge inm state",
+			    __func__);
+			goto out_im6f_rollback;
+		}
+
+		CTR1(KTR_MLD, "%s: doing mld downcall", __func__);
+		error = mld_change_state(inm, 0);
+		if (error) {
+			CTR1(KTR_MLD, "%s: failed mld downcall",
+			    __func__);
+		}
+	}
+
+	IN6_MULTI_UNLOCK();
+
+out_im6f_rollback:
+	if (error)
+		im6f_rollback(imf);
+	else
+		im6f_commit(imf);
+
+	im6f_reap(imf);
+
+	if (is_final) {
+		/* Remove the gap in the membership array. */
+		for (++idx; idx < imo->im6o_num_memberships; ++idx) {
+			imo->im6o_membership[idx-1] = imo->im6o_membership[idx];
+			imo->im6o_mfilters[idx-1] = imo->im6o_mfilters[idx];
+		}
+		imo->im6o_num_memberships--;
+	}
+
+out_in6p_locked:
+	INP_WUNLOCK(inp);
+	return (error);
+}
+
+/*
+ * Select the interface for transmitting IPv6 multicast datagrams.
+ *
+ * Either an instance of struct in6_addr or an instance of struct ipv6_mreqn
+ * may be passed to this socket option. An address of in6addr_any or an
+ * interface index of 0 is used to remove a previous selection.
+ * When no interface is selected, one is chosen for every send.
+ */
+static int
+in6p_set_multicast_if(struct inpcb *inp, struct sockopt *sopt)
+{
+	struct ifnet		*ifp;
+	struct ip6_moptions	*imo;
+	u_int			 ifindex;
+	int			 error;
+
+	if (sopt->sopt_valsize != sizeof(u_int))
+		return (EINVAL);
+
+	error = sooptcopyin(sopt, &ifindex, sizeof(u_int), sizeof(u_int));
+	if (error)
+		return (error);
+	if (ifindex < 0 || V_if_index < ifindex)
+		return (EINVAL);
+
+	ifp = ifnet_byindex(ifindex);
+	if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0)
+		return (EADDRNOTAVAIL);
+
+	imo = in6p_findmoptions(inp);
+	imo->im6o_multicast_ifp = ifp;
+	INP_WUNLOCK(inp);
+
+	return (0);
+}
+
+/*
+ * Atomically set source filters on a socket for an IPv6 multicast group.
+ *
+ * SMPng: NOTE: Potentially calls malloc(M_WAITOK) with Giant held.
+ */
+static int
+in6p_set_source_filters(struct inpcb *inp, struct sockopt *sopt)
+{
+	struct __msfilterreq	 msfr;
+	sockunion_t		*gsa;
+	struct ifnet		*ifp;
+	struct in6_mfilter	*imf;
+	struct ip6_moptions	*imo;
+	struct in6_multi		*inm;
+	size_t			 idx;
+	int			 error;
+
+	error = sooptcopyin(sopt, &msfr, sizeof(struct __msfilterreq),
+	    sizeof(struct __msfilterreq));
+	if (error)
+		return (error);
+
+	if (msfr.msfr_nsrcs > in6_mcast_maxsocksrc)
+		return (ENOBUFS);
+
+	if (msfr.msfr_fmode != MCAST_EXCLUDE &&
+	    msfr.msfr_fmode != MCAST_INCLUDE)
+		return (EINVAL);
+
+	if (msfr.msfr_group.ss_family != AF_INET6 ||
+	    msfr.msfr_group.ss_len != sizeof(struct sockaddr_in6))
+		return (EINVAL);
+
+	gsa = (sockunion_t *)&msfr.msfr_group;
+	if (!IN6_IS_ADDR_MULTICAST(&gsa->sin6.sin6_addr))
+		return (EINVAL);
+
+	gsa->sin6.sin6_port = 0;	/* ignore port */
+
+	if (msfr.msfr_ifindex == 0 || V_if_index < msfr.msfr_ifindex)
+		return (EADDRNOTAVAIL);
+	ifp = ifnet_byindex(msfr.msfr_ifindex);
+	if (ifp == NULL)
+		return (EADDRNOTAVAIL);
+	(void)in6_setscope(&gsa->sin6.sin6_addr, ifp, NULL);
+
+	/*
+	 * Take the INP write lock.
+	 * Check if this socket is a member of this group.
+	 */
+	imo = in6p_findmoptions(inp);
+	idx = im6o_match_group(imo, ifp, &gsa->sa);
+	if (idx == -1 || imo->im6o_mfilters == NULL) {
+		error = EADDRNOTAVAIL;
+		goto out_in6p_locked;
+	}
+	inm = imo->im6o_membership[idx];
+	imf = &imo->im6o_mfilters[idx];
+
+	/*
+	 * Begin state merge transaction at socket layer.
+	 */
+	INP_WLOCK_ASSERT(inp);
+
+	imf->im6f_st[1] = msfr.msfr_fmode;
+
+	/*
+	 * Apply any new source filters, if present.
+	 * Make a copy of the user-space source vector so
+	 * that we may copy them with a single copyin. This
+	 * allows us to deal with page faults up-front.
+	 */
+	if (msfr.msfr_nsrcs > 0) {
+		struct in6_msource	*lims;
+		struct sockaddr_in6	*psin;
+		struct sockaddr_storage	*kss, *pkss;
+		int			 i;
+
+		INP_WUNLOCK(inp);
+ 
+		CTR2(KTR_MLD, "%s: loading %lu source list entries",
+		    __func__, (unsigned long)msfr.msfr_nsrcs);
+		kss = malloc(sizeof(struct sockaddr_storage) * msfr.msfr_nsrcs,
+		    M_TEMP, M_WAITOK);
+		error = copyin(msfr.msfr_srcs, kss,
+		    sizeof(struct sockaddr_storage) * msfr.msfr_nsrcs);
+		if (error) {
+			free(kss, M_TEMP);
+			return (error);
+		}
+
+		INP_WLOCK(inp);
+
+		/*
+		 * Mark all source filters as UNDEFINED at t1.
+		 * Restore new group filter mode, as im6f_leave()
+		 * will set it to INCLUDE.
+		 */
+		im6f_leave(imf);
+		imf->im6f_st[1] = msfr.msfr_fmode;
+
+		/*
+		 * Update socket layer filters at t1, lazy-allocating
+		 * new entries. This saves a bunch of memory at the
+		 * cost of one RB_FIND() per source entry; duplicate
+		 * entries in the msfr_nsrcs vector are ignored.
+		 * If we encounter an error, rollback transaction.
+		 *
+		 * XXX This too could be replaced with a set-symmetric
+		 * difference like loop to avoid walking from root
+		 * every time, as the key space is common.
+		 */
+		for (i = 0, pkss = kss; i < msfr.msfr_nsrcs; i++, pkss++) {
+			psin = (struct sockaddr_in6 *)pkss;
+			if (psin->sin6_family != AF_INET6) {
+				error = EAFNOSUPPORT;
+				break;
+			}
+			if (psin->sin6_len != sizeof(struct sockaddr_in6)) {
+				error = EINVAL;
+				break;
+			}
+			if (IN6_IS_ADDR_MULTICAST(&psin->sin6_addr)) {
+				error = EINVAL;
+				break;
+			}
+			/*
+			 * TODO: Validate embedded scope ID in source
+			 * list entry against passed-in ifp, if and only
+			 * if source list filter entry is iface or node local.
+			 */
+			in6_clearscope(&psin->sin6_addr);
+			error = im6f_get_source(imf, psin, &lims);
+			if (error)
+				break;
+			lims->im6sl_st[1] = imf->im6f_st[1];
+		}
+		free(kss, M_TEMP);
+	}
+
+	if (error)
+		goto out_im6f_rollback;
+
+	INP_WLOCK_ASSERT(inp);
+	IN6_MULTI_LOCK();
+
+	/*
+	 * Begin state merge transaction at MLD layer.
+	 */
+	CTR1(KTR_MLD, "%s: merge inm state", __func__);
+	error = in6m_merge(inm, imf);
+	if (error) {
+		CTR1(KTR_MLD, "%s: failed to merge inm state", __func__);
+		goto out_im6f_rollback;
+	}
+
+	CTR1(KTR_MLD, "%s: doing mld downcall", __func__);
+	error = mld_change_state(inm, 0);
+	if (error)
+		CTR1(KTR_MLD, "%s: failed mld downcall", __func__);
+
+	IN6_MULTI_UNLOCK();
+
+out_im6f_rollback:
+	if (error)
+		im6f_rollback(imf);
+	else
+		im6f_commit(imf);
+
+	im6f_reap(imf);
+
+out_in6p_locked:
+	INP_WUNLOCK(inp);
+	return (error);
+}
+
+/*
+ * Set the IP multicast options in response to user setsockopt().
+ *
+ * Many of the socket options handled in this function duplicate the
+ * functionality of socket options in the regular unicast API. However,
+ * it is not possible to merge the duplicate code, because the idempotence
+ * of the IPv6 multicast part of the BSD Sockets API must be preserved;
+ * the effects of these options must be treated as separate and distinct.
+ *
+ * SMPng: XXX: Unlocked read of inp_socket believed OK.
+ */
+int
+ip6_setmoptions(struct inpcb *inp, struct sockopt *sopt)
+{
+	struct ip6_moptions	*im6o;
+	int			 error;
+
+	error = 0;
+
+	/*
+	 * If socket is neither of type SOCK_RAW or SOCK_DGRAM,
+	 * or is a divert socket, reject it.
+	 */
+	if (inp->inp_socket->so_proto->pr_protocol == IPPROTO_DIVERT ||
+	    (inp->inp_socket->so_proto->pr_type != SOCK_RAW &&
+	     inp->inp_socket->so_proto->pr_type != SOCK_DGRAM))
+		return (EOPNOTSUPP);
+
+	switch (sopt->sopt_name) {
+	case IPV6_MULTICAST_IF:
+		error = in6p_set_multicast_if(inp, sopt);
+		break;
+
+	case IPV6_MULTICAST_HOPS: {
+		int hlim;
+
+		if (sopt->sopt_valsize != sizeof(int)) {
+			error = EINVAL;
+			break;
+		}
+		error = sooptcopyin(sopt, &hlim, sizeof(hlim), sizeof(int));
+		if (error)
+			break;
+		if (hlim < -1 || hlim > 255) {
+			error = EINVAL;
+			break;
+		} else if (hlim == -1) {
+			hlim = V_ip6_defmcasthlim;
+		}
+		im6o = in6p_findmoptions(inp);
+		im6o->im6o_multicast_hlim = hlim;
+		INP_WUNLOCK(inp);
+		break;
+	}
+
+	case IPV6_MULTICAST_LOOP: {
+		u_int loop;
+
+		/*
+		 * Set the loopback flag for outgoing multicast packets.
+		 * Must be zero or one.
+		 */
+		if (sopt->sopt_valsize != sizeof(u_int)) {
+			error = EINVAL;
+			break;
+		}
+		error = sooptcopyin(sopt, &loop, sizeof(u_int), sizeof(u_int));
+		if (error)
+			break;
+		if (loop > 1) {
+			error = EINVAL;
+			break;
+		}
+		im6o = in6p_findmoptions(inp);
+		im6o->im6o_multicast_loop = loop;
+		INP_WUNLOCK(inp);
+		break;
+	}
+
+	case IPV6_JOIN_GROUP:
+	case MCAST_JOIN_GROUP:
+	case MCAST_JOIN_SOURCE_GROUP:
+		error = in6p_join_group(inp, sopt);
+		break;
+
+	case IPV6_LEAVE_GROUP:
+	case MCAST_LEAVE_GROUP:
+	case MCAST_LEAVE_SOURCE_GROUP:
+		error = in6p_leave_group(inp, sopt);
+		break;
+
+	case MCAST_BLOCK_SOURCE:
+	case MCAST_UNBLOCK_SOURCE:
+		error = in6p_block_unblock_source(inp, sopt);
+		break;
+
+	case IPV6_MSFILTER:
+		error = in6p_set_source_filters(inp, sopt);
+		break;
+
+	default:
+		error = EOPNOTSUPP;
+		break;
+	}
+
+	INP_UNLOCK_ASSERT(inp);
+
+	return (error);
+}
+
+/*
+ * Expose MLD's multicast filter mode and source list(s) to userland,
+ * keyed by (ifindex, group).
+ * The filter mode is written out as a uint32_t, followed by
+ * 0..n of struct in6_addr.
+ * For use by ifmcstat(8).
+ * SMPng: NOTE: unlocked read of ifindex space.
+ */
+static int
+sysctl_ip6_mcast_filters(SYSCTL_HANDLER_ARGS)
+{
+	struct in6_addr			 mcaddr;
+	struct in6_addr			 src;
+	struct ifnet			*ifp;
+	struct ifmultiaddr		*ifma;
+	struct in6_multi		*inm;
+	struct ip6_msource		*ims;
+	int				*name;
+	int				 retval;
+	u_int				 namelen;
+	uint32_t			 fmode, ifindex;
+#ifdef KTR
+	char				 ip6tbuf[INET6_ADDRSTRLEN];
+#endif
+
+	name = (int *)arg1;
+	namelen = arg2;
+
+	if (req->newptr != NULL)
+		return (EPERM);
+
+	/* int: ifindex + 4 * 32 bits of IPv6 address */
+	if (namelen != 5)
+		return (EINVAL);
+
+	ifindex = name[0];
+	if (ifindex <= 0 || ifindex > V_if_index) {
+		CTR2(KTR_MLD, "%s: ifindex %u out of range",
+		    __func__, ifindex);
+		return (ENOENT);
+	}
+
+	memcpy(&mcaddr, &name[1], sizeof(struct in6_addr));
+	if (!IN6_IS_ADDR_MULTICAST(&mcaddr)) {
+		CTR2(KTR_MLD, "%s: group %s is not multicast",
+		    __func__, ip6_sprintf(ip6tbuf, &mcaddr));
+		return (EINVAL);
+	}
+
+	ifp = ifnet_byindex(ifindex);
+	if (ifp == NULL) {
+		CTR2(KTR_MLD, "%s: no ifp for ifindex %u",
+		    __func__, ifindex);
+		return (ENOENT);
+	}
+	/*
+	 * Internal MLD lookups require that scope/zone ID is set.
+	 */
+	(void)in6_setscope(&mcaddr, ifp, NULL);
+
+	retval = sysctl_wire_old_buffer(req,
+	    sizeof(uint32_t) + (in6_mcast_maxgrpsrc * sizeof(struct in6_addr)));
+	if (retval)
+		return (retval);
+
+	IN6_MULTI_LOCK();
+
+	IF_ADDR_LOCK(ifp);
+	TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
+		if (ifma->ifma_addr->sa_family != AF_INET6 ||
+		    ifma->ifma_protospec == NULL)
+			continue;
+		inm = (struct in6_multi *)ifma->ifma_protospec;
+		if (!IN6_ARE_ADDR_EQUAL(&inm->in6m_addr, &mcaddr))
+			continue;
+		fmode = inm->in6m_st[1].iss_fmode;
+		retval = SYSCTL_OUT(req, &fmode, sizeof(uint32_t));
+		if (retval != 0)
+			break;
+		RB_FOREACH(ims, ip6_msource_tree, &inm->in6m_srcs) {
+			CTR2(KTR_MLD, "%s: visit node %p", __func__, ims);
+			/*
+			 * Only copy-out sources which are in-mode.
+			 */
+			if (fmode != im6s_get_mode(inm, ims, 1)) {
+				CTR1(KTR_MLD, "%s: skip non-in-mode",
+				    __func__);
+				continue;
+			}
+			src = ims->im6s_addr;
+			retval = SYSCTL_OUT(req, &src,
+			    sizeof(struct in6_addr));
+			if (retval != 0)
+				break;
+		}
+	}
+	IF_ADDR_UNLOCK(ifp);
+
+	IN6_MULTI_UNLOCK();
+
+	return (retval);
+}
+
+#ifdef KTR
+
+static const char *in6m_modestrs[] = { "un", "in", "ex" };
+
+static const char *
+in6m_mode_str(const int mode)
+{
+
+	if (mode >= MCAST_UNDEFINED && mode <= MCAST_EXCLUDE)
+		return (in6m_modestrs[mode]);
+	return ("??");
+}
+
+static const char *in6m_statestrs[] = {
+	"not-member",
+	"silent",
+	"idle",
+	"lazy",
+	"sleeping",
+	"awakening",
+	"query-pending",
+	"sg-query-pending",
+	"leaving"
+};
+
+static const char *
+in6m_state_str(const int state)
+{
+
+	if (state >= MLD_NOT_MEMBER && state <= MLD_LEAVING_MEMBER)
+		return (in6m_statestrs[state]);
+	return ("??");
+}
+
+/*
+ * Dump an in6_multi structure to the console.
+ */
+void
+in6m_print(const struct in6_multi *inm)
+{
+	int t;
+	char ip6tbuf[INET6_ADDRSTRLEN];
+
+	if ((ktr_mask & KTR_MLD) == 0)
+		return;
+
+	printf("%s: --- begin in6m %p ---\n", __func__, inm);
+	printf("addr %s ifp %p(%s) ifma %p\n",
+	    ip6_sprintf(ip6tbuf, &inm->in6m_addr),
+	    inm->in6m_ifp,
+	    inm->in6m_ifp->if_xname,
+	    inm->in6m_ifma);
+	printf("timer %u state %s refcount %u scq.len %u\n",
+	    inm->in6m_timer,
+	    in6m_state_str(inm->in6m_state),
+	    inm->in6m_refcount,
+	    inm->in6m_scq.ifq_len);
+	printf("mli %p nsrc %lu sctimer %u scrv %u\n",
+	    inm->in6m_mli,
+	    inm->in6m_nsrc,
+	    inm->in6m_sctimer,
+	    inm->in6m_scrv);
+	for (t = 0; t < 2; t++) {
+		printf("t%d: fmode %s asm %u ex %u in %u rec %u\n", t,
+		    in6m_mode_str(inm->in6m_st[t].iss_fmode),
+		    inm->in6m_st[t].iss_asm,
+		    inm->in6m_st[t].iss_ex,
+		    inm->in6m_st[t].iss_in,
+		    inm->in6m_st[t].iss_rec);
+	}
+	printf("%s: --- end in6m %p ---\n", __func__, inm);
+}
+
+#else /* !KTR */
+
+void
+in6m_print(const struct in6_multi *inm)
+{
+
+}
+
+#endif /* KTR */