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, 33 insertions, 5 deletions

diff --git a/usr.sbin/mtest/mtest.c b/usr.sbin/mtest/mtest.c
index 747a1f3..28c0fc6 100644
--- a/usr.sbin/mtest/mtest.c
+++ b/usr.sbin/mtest/mtest.c
@@ -55,6 +55,15 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <unistd.h>
 
+/* The following two socket options are private to the kernel and libc. */
+
+#ifndef IP_SETMSFILTER
+#define IP_SETMSFILTER 74 /* atomically set filter list */
+#endif
+#ifndef IP_GETMSFILTER
+#define IP_GETMSFILTER 75 /* get filter list */
+#endif
+
 static void	process_file(char *, int);
 static void	process_cmd(char*, int, FILE *fp);
 static void	usage(void);
@@ -135,14 +144,14 @@ process_cmd(char *cmd, int s, FILE *fp __unused)
 {
 	char			 str1[STR_SIZE];
 	char			 str2[STR_SIZE];
-#ifdef WITH_IGMPV3
 	char			 str3[STR_SIZE];
+#ifdef WITH_IGMPV3
 	char			 filtbuf[IP_MSFILTER_SIZE(MAX_ADDRS)];
 #endif
 	struct ifreq		 ifr;
 	struct ip_mreq		 imr;
-#ifdef WITH_IGMPV3
 	struct ip_mreq_source	 imrs;
+#ifdef WITH_IGMPV3
 	struct ip_msfilter	*imsfp;
 #endif
 	char			*line;
@@ -256,6 +265,7 @@ process_cmd(char *cmd, int s, FILE *fp __unused)
 	 */
 	case 'i':
 	case 'e':
+		/* XXX: SIOCSIPMSFILTER will be made an internal API. */
 		if ((sscanf(line, "%s %s %d", str1, str2, &n)) != 3) {
 			printf("-1\n");
 			break;
@@ -284,10 +294,13 @@ process_cmd(char *cmd, int s, FILE *fp __unused)
 		else
 			printf("ok\n");
 		break;
+#endif /* WITH_IGMPV3 */
 
 	/*
 	 * Allow or block traffic from a source, using the
 	 * delta based api.
+	 * XXX: Currently we allow this to be used with the ASM-only
+	 *      implementation of RFC3678 in FreeBSD 7. 
 	 */
 	case 't':
 	case 'b':
@@ -302,6 +315,8 @@ process_cmd(char *cmd, int s, FILE *fp __unused)
 			break;
 		}
 
+#ifdef WITH_IGMPV3
+		/* XXX: SIOCSIPMSFILTER will be made an internal API. */
 		/* First determine out current filter mode. */
 		imsfp = (struct ip_msfilter *)filtbuf;
 		imsfp->imsf_multiaddr.s_addr = imrs.imr_multiaddr.s_addr;
@@ -325,13 +340,22 @@ process_cmd(char *cmd, int s, FILE *fp __unused)
 			opt = (*cmd == 't') ? IP_ADD_SOURCE_MEMBERSHIP :
 			    IP_DROP_SOURCE_MEMBERSHIP;
 		}
+#else /* !WITH_IGMPV3 */
+		/*
+		 * Don't look before we leap; we may only block or unblock
+		 * sources on a socket in exclude mode.
+		 */
+		opt = (*cmd == 't') ? IP_UNBLOCK_SOURCE : IP_BLOCK_SOURCE;
+#endif /* WITH_IGMPV3 */
 		if (setsockopt(s, IPPROTO_IP, opt, &imrs, sizeof(imrs)) == -1)
 			warn("ioctl IP_ADD_SOURCE_MEMBERSHIP/IP_DROP_SOURCE_MEMBERSHIP/IP_UNBLOCK_SOURCE/IP_BLOCK_SOURCE");
 		else
 			printf("ok\n");
 		break;
 
+#ifdef WITH_IGMPV3
 	case 'g':
+		/* XXX: SIOCSIPMSFILTER will be made an internal API. */
 		if ((sscanf(line, "%s %s %d", str1, str2, &n)) != 3) {
 			printf("-1\n");
 			break;
@@ -360,11 +384,11 @@ process_cmd(char *cmd, int s, FILE *fp __unused)
 				printf("%s\n", inet_ntoa(imsfp->imsf_slist[i]));
 		}
 		break;
-#else	/* !WITH_IGMPV3 */
+#endif	/* !WITH_IGMPV3 */
+
+#ifndef WITH_IGMPV3
 	case 'i':
 	case 'e':
-	case 't':
-	case 'b':
 	case 'g':
 		printf("warning: IGMPv3 is not supported by this version "
 		    "of FreeBSD; command ignored.\n");
@@ -389,11 +413,15 @@ usage(void)
 	printf("d ifname e.e.e.e.e.e       - delete ether multicast address\n");
 	printf("m ifname 1/0               - set/clear ether allmulti flag\n");
 	printf("p ifname 1/0               - set/clear ether promisc flag\n");
+#ifdef WITH_IGMPv3
 	printf("i g.g.g.g i.i.i.i n        - set n include mode src filter\n");
 	printf("e g.g.g.g i.i.i.i n        - set n exclude mode src filter\n");
+#endif
 	printf("t g.g.g.g i.i.i.i s.s.s.s  - allow traffic from src\n");
 	printf("b g.g.g.g i.i.i.i s.s.s.s  - block traffic from src\n");
+#ifdef WITH_IGMPV3
 	printf("g g.g.g.g i.i.i.i n        - get and show n src filters\n");
+#endif
 	printf("f filename                 - read command(s) from file\n");
 	printf("s seconds                  - sleep for some time\n");
 	printf("q                          - quit\n");