Import rewrite of IPv4 socket multicast layer to support source-specific

and protocol-independent host mode multicast. The code is written to
accomodate IPv6, IGMPv3 and MLDv2 with only a little additional work.

This change only pertains to FreeBSD's use as a multicast end-station and
does not concern multicast routing; for an IGMPv3/MLDv2 router
implementation, consider the XORP project.

The work is based on Wilbert de Graaf's IGMPv3 code drop for FreeBSD 4.6,
which is available at: http://www.kloosterhof.com/wilbert/igmpv3.html

Summary
 * IPv4 multicast socket processing is now moved out of ip_output.c
   into a new module, in_mcast.c.
 * The in_mcast.c module implements the IPv4 legacy any-source API in
   terms of the protocol-independent source-specific API.
 * Source filters are lazy allocated as the common case does not use them.
   They are part of per inpcb state and are covered by the inpcb lock.
 * struct ip_mreqn is now supported to allow applications to specify
   multicast joins by interface index in the legacy IPv4 any-source API.
 * In UDP, an incoming multicast datagram only requires that the source
   port matches the 4-tuple if the socket was already bound by source port.
   An unbound socket SHOULD be able to receive multicasts sent from an
   ephemeral source port.
 * The UDP socket multicast filter mode defaults to exclusive, that is,
   sources present in the per-socket list will be blocked from delivery.
 * The RFC 3678 userland functions have been added to libc: setsourcefilter,
   getsourcefilter, setipv4sourcefilter, getipv4sourcefilter.
 * Definitions for IGMPv3 are merged but not yet used.
 * struct sockaddr_storage is now referenced from <netinet/in.h>. It
   is therefore defined there if not already declared in the same way
   as for the C99 types.
 * The RFC 1724 hack (specify 0.0.0.0/8 addresses to IP_MULTICAST_IF
   which are then interpreted as interface indexes) is now deprecated.
 * A patch for the Rhyolite.com routed in the FreeBSD base system
   is available in the -net archives. This only affects individuals
   running RIPv1 or RIPv2 via point-to-point and/or unnumbered interfaces.
 * Make IPv6 detach path similar to IPv4's in code flow; functionally same.
 * Bump __FreeBSD_version to 700048; see UPDATING.

This work was financially supported by another FreeBSD committer.

Obtained from:  p4://bms_netdev
Submitted by:   Wilbert de Graaf (original work)
Reviewed by:    rwatson (locking), silence from fenner,
		net@ (but with encouragement)

1 files changed, 22 insertions, 10 deletions

diff --git a/sys/netinet6/in6_ifattach.c b/sys/netinet6/in6_ifattach.c
index b78b5c9..e00e7fa 100644
--- a/sys/netinet6/in6_ifattach.c
+++ b/sys/netinet6/in6_ifattach.c
@@ -76,6 +76,7 @@ static int generate_tmp_ifid __P((u_int8_t *, const u_int8_t *, u_int8_t *));
 static int get_ifid __P((struct ifnet *, struct ifnet *, struct in6_addr *));
 static int in6_ifattach_linklocal __P((struct ifnet *, struct ifnet *));
 static int in6_ifattach_loopback __P((struct ifnet *));
+static void in6_purgemaddrs __P((struct ifnet *));
 
 #define EUI64_GBIT	0x01
 #define EUI64_UBIT	0x02
@@ -798,18 +799,10 @@ in6_ifdetach(ifp)
 		IFAFREE(&oia->ia_ifa);
 	}
 
-	/* leave from all multicast groups joined */
-
 	in6_pcbpurgeif0(&udbinfo, ifp);
 	in6_pcbpurgeif0(&ripcbinfo, ifp);
-
-	for (in6m = LIST_FIRST(&in6_multihead); in6m; in6m = in6m_next) {
-		in6m_next = LIST_NEXT(in6m, in6m_entry);
-		if (in6m->in6m_ifp != ifp)
-			continue;
-		in6_delmulti(in6m);
-		in6m = NULL;
-	}
+	/* leave from all multicast groups joined */
+	in6_purgemaddrs(ifp);
 
 	/*
 	 * remove neighbor management table.  we call it twice just to make
@@ -898,3 +891,22 @@ in6_tmpaddrtimer(ignored_arg)
 
 	splx(s);
 }
+
+static void
+in6_purgemaddrs(ifp)
+	struct ifnet *ifp;
+{
+	struct in6_multi *in6m;
+	struct in6_multi *oin6m;
+
+#ifdef DIAGNOSTIC
+	printf("%s: purging ifp %p\n", __func__, ifp);
+#endif
+
+	IFF_LOCKGIANT(ifp);
+	LIST_FOREACH_SAFE(in6m, &in6_multihead, in6m_entry, oin6m) {
+		if (in6m->in6m_ifp == ifp)
+			in6_delmulti(in6m);
+	}
+	IFF_UNLOCKGIANT(ifp);
+}