freebsd-ports/net/sock/files/patch-src__multicast.c

--- src/multicast.c.orig	2010-05-28 00:03:25 UTC
+++ src/multicast.c
@@ -10,24 +10,96 @@
 
 #include	"sock.h"
 
+/*
+ * Works for IPv4 and IPv6.
+ * For IPv4, the server is able to join a multicast group such as 224.0.0.1.
+ * The client is able to connect to the same multicast address and port
+ * assigned to the server.  The client can then send data, which the server 
+ * receives.
+ * For IPv6, the server is able to join a multicast group of the form ff02::n.
+ * The client is never able to connect to that address/port, however.
+ */
 void
-join_mcast(int fd, struct sockaddr_in *sin)
+join_mcast_server(int fd, struct sockaddr_in *sin, struct sockaddr_in6 *sin6)
 {
 #ifdef	IP_ADD_MEMBERSHIP	/* only include if host supports mcasting */
-	u_long			inaddr;
-	struct ip_mreq	mreq;
+	u_long		 inaddr;
+	struct ip_mreq	 mreq;
+	struct ipv6_mreq mreq6;
 
-	inaddr = sin->sin_addr.s_addr;
-	if (IN_MULTICAST(inaddr) == 0)
-		return;			/* not a multicast address */
+	if (af_46 == AF_INET) {
+		inaddr = sin->sin_addr.s_addr;
+		/*
+		 * FreeBSD 8.4:  IN_MULTICAST() test fails in the original code
+		 * because it was testing inaddr with the wrong endianness.
+		 * Fixed in this version of the code, at least for FreeBSD.
+		 */
+		inaddr = ntohl(inaddr);
 
-	mreq.imr_multiaddr.s_addr = inaddr;
-	mreq.imr_interface.s_addr = htonl(INADDR_ANY);	/* need way to change */
-	if (setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq,
-												sizeof(mreq)) == -1 )
-		err_sys("IP_ADD_MEMBERSHIP error");
+		if (IN_MULTICAST(inaddr) == 0) {
+			return;			/* not a multicast address */
+		}
+	} else {
+		if (IN6_IS_ADDR_MULTICAST(&(sin6->sin6_addr)) == 0) {
+			return;			/* not a multicast address */
+		}
+	}
+
+	if (af_46 == AF_INET) {
+		mreq.imr_multiaddr.s_addr = sin->sin_addr.s_addr;
+		/* need way to change */
+		mreq.imr_interface.s_addr = htonl(INADDR_ANY);
+		if (setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq,
+		    sizeof(mreq)) == -1 ) {
+			err_sys("IP_ADD_MEMBERSHIP error");
+		}
+	} else {
+		memset((char *)&mreq6, 0, sizeof(mreq6));
+		mreq6.ipv6mr_multiaddr = sin6->sin6_addr;
+		mreq6.ipv6mr_interface = sin6->sin6_scope_id;
+		if (setsockopt(fd, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq6,
+		    sizeof(mreq6)) == -1 ) {
+			err_sys("IP_ADD_MEMBERSHIP error");
+		}
+	}
 
 	if (verbose)
-			fprintf(stderr, "multicast group joined\n");
+		fprintf(stderr, "multicast group joined\n");
+#endif	/* IP_ADD_MEMBERSHIP */
+}
+
+/*
+ * Added for IPv6.  Fixme:  Does not work at present.
+ * The client is currently unable to connect to the multicast address/port
+ * which was joined by the server.  A function similar to this may be needed
+ * to permit that connection to be made.
+ */
+void
+join_mcast_client(int fd,
+		  struct sockaddr_in *cli_sin, struct sockaddr_in6 *cli_sin6,
+		  struct sockaddr_in *serv_sin, struct sockaddr_in6 *serv_sin6)
+{
+#ifdef	IP_ADD_MEMBERSHIP	/* only include if host supports mcasting */
+	struct ipv6_mreq mreq6;
+
+	if (af_46 == AF_INET6) {
+		if (IN6_IS_ADDR_MULTICAST(&(serv_sin6->sin6_addr)) == 0) {
+			return;			/* not a multicast address */
+		}
+	}
+
+	if (af_46 == AF_INET6) {
+		memset((char *)&mreq6, 0, sizeof(mreq6));
+		mreq6.ipv6mr_multiaddr = serv_sin6->sin6_addr;
+		mreq6.ipv6mr_interface = serv_sin6->sin6_scope_id;
+		if (setsockopt(fd, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq6,
+		    sizeof(mreq6)) == -1 ) {
+			err_sys("IP_ADD_MEMBERSHIP error");
+		}
+	}
+
+	if (verbose) {
+		fprintf(stderr, "multicast group joined\n");
+	}
 #endif	/* IP_ADD_MEMBERSHIP */
 }