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, 3 insertions, 0 deletions

diff --git a/sys/netinet/ip_carp.c b/sys/netinet/ip_carp.c
index 32b8680..4cabe30 100644
--- a/sys/netinet/ip_carp.c
+++ b/sys/netinet/ip_carp.c
@@ -380,6 +380,7 @@ carp_clone_create(struct if_clone *ifc, int unit, caddr_t params)
 	sc->sc_imo.imo_membership = (struct in_multi **)malloc(
 	    (sizeof(struct in_multi *) * IP_MIN_MEMBERSHIPS), M_CARP,
 	    M_WAITOK);
+	sc->sc_imo.imo_mfilters = NULL;
 	sc->sc_imo.imo_max_memberships = IP_MIN_MEMBERSHIPS;
 	sc->sc_imo.imo_multicast_vif = -1;
 
@@ -1397,6 +1398,8 @@ carp_multicast_cleanup(struct carp_softc *sc)
 			imo->imo_membership[n] = NULL;
 		}
 	}
+	KASSERT(imo->imo_mfilters == NULL,
+	   ("%s: imo_mfilters != NULL", __func__));
 	imo->imo_num_memberships = 0;
 	imo->imo_multicast_ifp = NULL;
 }