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, 38 insertions, 1 deletions

diff --git a/sys/netinet/igmp.h b/sys/netinet/igmp.h
index 05a70fc..4c2f9e0 100644
--- a/sys/netinet/igmp.h
+++ b/sys/netinet/igmp.h
@@ -55,7 +55,42 @@ struct igmp {
 	struct in_addr	igmp_group;	/* group address being reported    */
 };					/*  (zero for queries)             */
 
-#define IGMP_MINLEN		     8
+struct igmpv3 {
+	u_char		igmp_type;	/* version & type of IGMP message  */
+	u_char		igmp_code;	/* subtype for routing msgs        */
+	u_short		igmp_cksum;	/* IP-style checksum               */
+	struct in_addr	igmp_group;	/* group address being reported    */
+					/*  (zero for queries)             */
+	u_char		igmp_misc;	/* reserved/suppress/robustness    */
+	u_char		igmp_qqi;	/* querier's query interval        */
+	u_short		igmp_numsrc;	/* number of sources               */
+	/*struct in_addr	igmp_sources[1];*/ /* source addresses */
+};
+
+struct igmp_grouprec {
+	u_char		ig_type;	/* record type */
+	u_char		ig_datalen;	/* length of auxiliary data */
+	u_short		ig_numsrc;	/* number of sources */
+	struct in_addr	ig_group;	/* group address being reported */
+	/*struct in_addr	ig_sources[1];*/ /* source addresses */
+};
+
+struct igmp_report {
+	u_char		ir_type;	/* record type */
+	u_char		ir_rsv1;	/* reserved */
+	u_short		ir_cksum;	/* checksum */
+	u_short		ir_rsv2;	/* reserved */
+	u_short		ir_numgrps;	/* number of group records */
+	struct		igmp_grouprec ir_groups[1];	/* group records */
+};
+
+#define IGMP_MINLEN			8
+#define IGMP_HDRLEN			8
+#define IGMP_GRPREC_HDRLEN		8
+#define IGMP_PREPEND			0
+
+#define IGMP_QRV(pigmp)			((pigmp)->igmp_misc & (0x07)) /* XXX */
+#define IGMP_MAXSOURCES(len)		(((len) - 12) >> 2) /* XXX */
 
 /*
  * Message types, including version number.
@@ -71,6 +106,8 @@ struct igmp {
 #define IGMP_MTRACE_RESP		0x1e  /* traceroute resp.(to sender)*/
 #define IGMP_MTRACE			0x1f  /* mcast traceroute messages  */
 
+#define IGMP_V3_MEMBERSHIP_REPORT	0x22	/* Ver. 3 membership report */
+
 #define IGMP_MAX_HOST_REPORT_DELAY   10    /* max delay for response to     */
 					   /*  query (in seconds) according */
 					   /*  to RFC1112                   */