netdev - [PATCH net] bridge: do not add port to router list when receives query with source 0.0.0.0

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Date:   Fri, 26 Oct 2018 10:28:43 +0800
From:   Hangbin Liu <liuhangbin@...il.com>
To:     netdev@...r.kernel.org
Cc:     Nikolay Aleksandrov <nikolay@...ulusnetworks.com>,
        Jiri Pirko <jiri@...lanox.com>,
        Linus Lüssing <linus.luessing@...3.blue>,
        "David S. Miller" <davem@...emloft.net>,
        Hangbin Liu <liuhangbin@...il.com>
Subject: [PATCH net] bridge: do not add port to router list when receives query with source 0.0.0.0

Based on RFC 4541, 2.1.1.  IGMP Forwarding Rules

  The switch supporting IGMP snooping must maintain a list of
  multicast routers and the ports on which they are attached.  This
  list can be constructed in any combination of the following ways:

  a) This list should be built by the snooping switch sending
     Multicast Router Solicitation messages as described in IGMP
     Multicast Router Discovery [MRDISC].  It may also snoop
     Multicast Router Advertisement messages sent by and to other
     nodes.

  b) The arrival port for IGMP Queries (sent by multicast routers)
     where the source address is not 0.0.0.0.

We should not add the port to router list when receives query with source
0.0.0.0.

Reported-by: Ying Xu <yinxu@...hat.com>
Signed-off-by: Hangbin Liu <liuhangbin@...il.com>
---
 net/bridge/br_multicast.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 024139b..41cdafb 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1422,7 +1422,15 @@ static void br_multicast_query_received(struct net_bridge *br,
 		return;
 
 	br_multicast_update_query_timer(br, query, max_delay);
-	br_multicast_mark_router(br, port);
+
+	/* Based on RFC4541, section 2.1.1 IGMP Forwarding Rules,
+	 * the arrival port for IGMP Queries where the source address
+	 * is 0.0.0.0 should not be added to router port list.
+	 */
+	if ((saddr->proto == htons(ETH_P_IP) && saddr->u.ip4) ||
+	    (saddr->proto == htons(ETH_P_IPV6) &&
+	     !ipv6_addr_any(&saddr->u.ip6)))
+		br_multicast_mark_router(br, port);
 }
 
 static void br_ip4_multicast_query(struct net_bridge *br,
-- 
2.5.5