pimd: IGMP conformance 5.10 test case is failing

Test case 5.10 sends leave message to unicast address, the leave
packet is accepted and a query message is sent in response to this.
No validation for address is present in the function

Add check for addresses as per RFC. Leave messages are allowed only
sent to either ALL-ROUTERS (224.0.0.2) or group address.

Signed-off-by: Mobashshera Rasool <mrasool@vmware.com>

1 files changed, 28 insertions, 3 deletions

diff --git a/pimd/pim_igmpv2.c b/pimd/pim_igmpv2.c
index d836c66cbb..7f3c7a0f8c 100644
--- a/pimd/pim_igmpv2.c
+++ b/pimd/pim_igmpv2.c
@@ -158,12 +158,13 @@ int igmp_v2_recv_report(struct igmp_sock *igmp, struct in_addr from,
 	return 0;
 }
 
-int igmp_v2_recv_leave(struct igmp_sock *igmp, struct in_addr from,
+int igmp_v2_recv_leave(struct igmp_sock *igmp, struct ip *ip_hdr,
 		       const char *from_str, char *igmp_msg, int igmp_msg_len)
 {
 	struct interface *ifp = igmp->interface;
 	struct in_addr group_addr;
 	char group_str[INET_ADDRSTRLEN];
+	struct in_addr from = ip_hdr->ip_src;
 
 	on_trace(__func__, igmp->interface, from);
 
@@ -184,8 +185,6 @@ int igmp_v2_recv_leave(struct igmp_sock *igmp, struct in_addr from,
 		return -1;
 	}
 
-	/* Collecting IGMP Rx stats */
-	igmp->rx_stats.leave_v2++;
 
 	memcpy(&group_addr, igmp_msg + 4, sizeof(struct in_addr));
 
@@ -195,6 +194,32 @@ int igmp_v2_recv_leave(struct igmp_sock *igmp, struct in_addr from,
 		zlog_debug("Recv IGMPv2 LEAVE from %s on %s for %s", from_str,
 			   ifp->name, group_str);
 	}
+	/*
+	 * As per RFC 2236, section 9:
+	 Message Type                  Destination Group
+	 ------------                  -----------------
+	 General Query                 ALL-SYSTEMS (224.0.0.1)
+	 Group-Specific Query          The group being queried
+	 Membership Report             The group being reported
+	 Leave Message                 ALL-ROUTERS (224.0.0.2)
+
+	 Note: in older (i.e., non-standard and now obsolete) versions of
+	 IGMPv2, hosts send Leave Messages to the group being left.  A
+	 router SHOULD accept Leave Messages addressed to the group being
+	 left in the interests of backwards compatibility with such hosts.
+	 In all cases, however, hosts MUST send to the ALL-ROUTERS address
+	 to be compliant with this specification.
+	*/
+	if ((ntohl(ip_hdr->ip_dst.s_addr) != INADDR_ALLRTRS_GROUP)
+	    && (ip_hdr->ip_dst.s_addr != group_addr.s_addr)) {
+		if (PIM_DEBUG_IGMP_EVENTS)
+			zlog_debug(
+				"IGMPv2 Leave message is ignored since received on address other than ALL-ROUTERS or Group-address");
+		return -1;
+	}
+
+	/* Collecting IGMP Rx stats */
+	igmp->rx_stats.leave_v2++;
 
 	/*
 	 * RFC 3376