pimd: fix IGMP receive handling

IGMP packets received from a source that does not match the subnet
of any configured addresses on the receive interface should be
ignored.
Also, find and use the correct IGMP socket object for the received
IGMP packet.

Signed-off-by: Nathan Bahr <nbahr@atcorp.com>
Signed-off-by: Jafar Al-Gharaibeh <jafar@atcorp.com>

1 files changed, 23 insertions, 27 deletions

diff --git a/pimd/pim_mroute.c b/pimd/pim_mroute.c
index 9060b6a95..0bccba397 100644
--- a/pimd/pim_mroute.c
+++ b/pimd/pim_mroute.c
@@ -592,12 +592,9 @@ static int pim_mroute_msg(struct pim_instance *pim, const char *buf,
 	struct pim_interface *pim_ifp;
 	const struct ip *ip_hdr;
 	const struct igmpmsg *msg;
-	char ip_src_str[INET_ADDRSTRLEN] = "";
-	char ip_dst_str[INET_ADDRSTRLEN] = "";
-	char src_str[INET_ADDRSTRLEN] = "<src?>";
-	char grp_str[INET_ADDRSTRLEN] = "<grp?>";
 	struct in_addr ifaddr;
 	struct igmp_sock *igmp;
+	const struct prefix *connected_src;
 
 	if (buf_size < (int)sizeof(struct ip))
 		return 0;
@@ -617,34 +614,37 @@ static int pim_mroute_msg(struct pim_instance *pim, const char *buf,
 		if (!ifp || !ifp->info)
 			return 0;
 
+		connected_src = pim_if_connected_to_source(ifp, ip_hdr->ip_src);
+
+		if (!connected_src) {
+			if (PIM_DEBUG_IGMP_PACKETS) {
+				zlog_debug("Recv IGMP packet on interface: %s from a non-connected source: %pI4",
+					   ifp->name, &ip_hdr->ip_src);
+			}
+			return 0;
+		}
+
 		pim_ifp = ifp->info;
-		ifaddr = pim_find_primary_addr(ifp);
-		igmp = pim_igmp_sock_lookup_ifaddr(pim_ifp->igmp_socket_list,
-						   ifaddr);
+		ifaddr = connected_src->u.prefix4;
+		igmp = pim_igmp_sock_lookup_ifaddr(pim_ifp->igmp_socket_list, ifaddr);
 
 		if (PIM_DEBUG_MROUTE) {
-			pim_inet4_dump("<src?>", ip_hdr->ip_src, ip_src_str,
-				       sizeof(ip_src_str));
-			pim_inet4_dump("<dst?>", ip_hdr->ip_dst, ip_dst_str,
-				       sizeof(ip_dst_str));
-
 			zlog_debug(
-				"%s(%s): igmp kernel upcall on %s(%p) for %s -> %s",
+				"%s(%s): igmp kernel upcall on %s(%p) for %pI4 -> %pI4",
 				__func__, pim->vrf->name, ifp->name, igmp,
-				ip_src_str, ip_dst_str);
+				&ip_hdr->ip_src, &ip_hdr->ip_dst);
 		}
 		if (igmp)
 			pim_igmp_packet(igmp, (char *)buf, buf_size);
-
+		else if (PIM_DEBUG_IGMP_PACKETS) {
+			zlog_debug("No IGMP socket on interface: %s with connected source: %pFX",
+				   ifp->name, connected_src);
+		}
 	} else if (ip_hdr->ip_p) {
 		if (PIM_DEBUG_MROUTE_DETAIL) {
-			pim_inet4_dump("<src?>", ip_hdr->ip_src, src_str,
-				       sizeof(src_str));
-			pim_inet4_dump("<grp?>", ip_hdr->ip_dst, grp_str,
-				       sizeof(grp_str));
 			zlog_debug(
-				"%s: no kernel upcall proto=%d src: %s dst: %s msg_size=%d",
-				__func__, ip_hdr->ip_p, src_str, grp_str,
+				"%s: no kernel upcall proto=%d src: %pI4 dst: %pI4 msg_size=%d",
+				__func__, ip_hdr->ip_p, &ip_hdr->ip_src, &ip_hdr->ip_dst,
 				buf_size);
 		}
 
@@ -656,15 +656,11 @@ static int pim_mroute_msg(struct pim_instance *pim, const char *buf,
 		if (!ifp)
 			return 0;
 		if (PIM_DEBUG_MROUTE) {
-			pim_inet4_dump("<src?>", msg->im_src, src_str,
-				       sizeof(src_str));
-			pim_inet4_dump("<grp?>", msg->im_dst, grp_str,
-				       sizeof(grp_str));
 			zlog_debug(
-				"%s: pim kernel upcall %s type=%d ip_p=%d from fd=%d for (S,G)=(%s,%s) on %s vifi=%d  size=%d",
+				"%s: pim kernel upcall %s type=%d ip_p=%d from fd=%d for (S,G)=(%pI4,%pI4) on %s vifi=%d  size=%d",
 				__func__, igmpmsgtype2str[msg->im_msgtype],
 				msg->im_msgtype, ip_hdr->ip_p,
-				pim->mroute_socket, src_str, grp_str, ifp->name,
+				pim->mroute_socket, &msg->im_src, &msg->im_dst, ifp->name,
 				msg->im_vif, buf_size);
 		}