Update routed to use the RFC 3678 protocol-independent multicast API. Use

IP_MULTICAST_IF with struct ip_mreqn (obtained from Linux) to tell the
stack which interface index to use for sending IPv4 datagrams.

Submitted by:	bms
Tested by:	phk

1 files changed, 31 insertions, 48 deletions

diff --git a/sbin/routed/rdisc.c b/sbin/routed/rdisc.c
index 047b3d1..496f212 100644
--- a/sbin/routed/rdisc.c
+++ b/sbin/routed/rdisc.c
@@ -168,7 +168,8 @@ void
 set_rdisc_mg(struct interface *ifp,
 	     int on)			/* 0=turn it off */
 {
-	struct ip_mreq m;
+	struct group_req gr;
+	struct sockaddr_in *sin;
 
 	if (rdisc_sock < 0) {
 		/* Create the raw socket so that we can hear at least
@@ -185,39 +186,35 @@ set_rdisc_mg(struct interface *ifp,
 		return;
 	}
 
-#ifdef MCAST_PPP_BUG
-	if (ifp->int_if_flags & IFF_POINTOPOINT)
-		return;
-#endif
-	memset(&m, 0, sizeof(m));
-#ifdef MCAST_IFINDEX
-	m.imr_interface.s_addr = htonl(ifp->int_index);
-#else
-	m.imr_interface.s_addr = ((ifp->int_if_flags & IFF_POINTOPOINT)
-				  ? ifp->int_dstaddr
-				  : ifp->int_addr);
+	memset(&gr, 0, sizeof(gr));
+	gr.gr_interface = ifp->int_index;
+	sin = (struct sockaddr_in *)&gr.gr_group;
+	sin->sin_family = AF_INET;
+#ifdef _HAVE_SIN_LEN
+	sin->sin_len = sizeof(struct sockaddr_in);
 #endif
+
 	if (supplier
 	    || (ifp->int_state & IS_NO_ADV_IN)
 	    || !on) {
 		/* stop listening to advertisements
 		 */
 		if (ifp->int_state & IS_ALL_HOSTS) {
-			m.imr_multiaddr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
+			sin->sin_addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
 			if (setsockopt(rdisc_sock, IPPROTO_IP,
-				       IP_DROP_MEMBERSHIP,
-				       &m, sizeof(m)) < 0)
-				LOGERR("IP_DROP_MEMBERSHIP ALLHOSTS");
+				       MCAST_LEAVE_GROUP,
+				       &gr, sizeof(gr)) < 0)
+				LOGERR("MCAST_LEAVE_GROUP ALLHOSTS");
 			ifp->int_state &= ~IS_ALL_HOSTS;
 		}
 
 	} else if (!(ifp->int_state & IS_ALL_HOSTS)) {
 		/* start listening to advertisements
 		 */
-		m.imr_multiaddr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
-		if (setsockopt(rdisc_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
-			       &m, sizeof(m)) < 0) {
-			LOGERR("IP_ADD_MEMBERSHIP ALLHOSTS");
+		sin->sin_addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
+		if (setsockopt(rdisc_sock, IPPROTO_IP, MCAST_JOIN_GROUP,
+			       &gr, sizeof(gr)) < 0) {
+			LOGERR("MCAST_JOIN_GROUP ALLHOSTS");
 		} else {
 			ifp->int_state |= IS_ALL_HOSTS;
 		}
@@ -229,21 +226,21 @@ set_rdisc_mg(struct interface *ifp,
 		/* stop listening to solicitations
 		 */
 		if (ifp->int_state & IS_ALL_ROUTERS) {
-			m.imr_multiaddr.s_addr=htonl(INADDR_ALLROUTERS_GROUP);
+			sin->sin_addr.s_addr = htonl(INADDR_ALLROUTERS_GROUP);
 			if (setsockopt(rdisc_sock, IPPROTO_IP,
-				       IP_DROP_MEMBERSHIP,
-				       &m, sizeof(m)) < 0)
-				LOGERR("IP_DROP_MEMBERSHIP ALLROUTERS");
+				       MCAST_LEAVE_GROUP,
+				       &gr, sizeof(gr)) < 0)
+				LOGERR("MCAST_LEAVE_GROUP ALLROUTERS");
 			ifp->int_state &= ~IS_ALL_ROUTERS;
 		}
 
 	} else if (!(ifp->int_state & IS_ALL_ROUTERS)) {
 		/* start hearing solicitations
 		 */
-		m.imr_multiaddr.s_addr=htonl(INADDR_ALLROUTERS_GROUP);
-		if (setsockopt(rdisc_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
-			       &m, sizeof(m)) < 0) {
-			LOGERR("IP_ADD_MEMBERSHIP ALLROUTERS");
+		sin->sin_addr.s_addr = htonl(INADDR_ALLROUTERS_GROUP);
+		if (setsockopt(rdisc_sock, IPPROTO_IP, MCAST_JOIN_GROUP,
+			       &gr, sizeof(gr)) < 0) {
+			LOGERR("MCAST_JOIN_GROUP ALLROUTERS");
 		} else {
 			ifp->int_state |= IS_ALL_ROUTERS;
 		}
@@ -699,7 +696,6 @@ send_rdisc(union ad_u *p,
 	struct sockaddr_in rsin;
 	int flags;
 	const char *msg;
-	naddr tgt_mcast;
 
 
 	memset(&rsin, 0, sizeof(rsin));
@@ -736,27 +732,14 @@ send_rdisc(union ad_u *p,
 		}
 		if (rdisc_sock_mcast != ifp) {
 			/* select the right interface. */
-#ifdef MCAST_IFINDEX
-			/* specify ifindex */
-			tgt_mcast = htonl(ifp->int_index);
-#else
-#ifdef MCAST_PPP_BUG
-			/* Do not specify the primary interface explicitly
-			 * if we have the multicast point-to-point kernel
-			 * bug, since the kernel will do the wrong thing
-			 * if the local address of a point-to-point link
-			 * is the same as the address of an ordinary
-			 * interface.
-			 */
-			if (ifp->int_addr == myaddr) {
-				tgt_mcast = 0;
-			} else
-#endif
-			tgt_mcast = ifp->int_addr;
-#endif
+			struct ip_mreqn mreqn;
+
+			memset(&mreqn, 0, sizeof(struct ip_mreqn));
+			mreqn.imr_ifindex = ifp->int_index;
 			if (0 > setsockopt(rdisc_sock,
 					   IPPROTO_IP, IP_MULTICAST_IF,
-					   &tgt_mcast, sizeof(tgt_mcast))) {
+					   &mreqn,
+					   sizeof(mreqn))) {
 				LOGERR("setsockopt(rdisc_sock,"
 				       "IP_MULTICAST_IF)");
 				rdisc_sock_mcast = 0;