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authorFernando Luis Vázquez Cao <fernando@oss.ntt.co.jp>2011-06-13 15:04:43 +0000
committerDavid S. Miller <davem@conan.davemloft.net>2011-06-16 23:14:12 -0400
commit62b2bcb49cca72f6d3f39f831127a6ab315a475d (patch)
treeedb756747c2fcabb74d8422a7adb84e3a7bb3386 /net
parentd40261236e8e278cb1936cb5e934262971692b10 (diff)
downloadlinux-62b2bcb49cca72f6d3f39f831127a6ab315a475d.tar.gz
IGMP snooping: set mrouters_only flag for IPv4 traffic properly
Upon reception of a IGMP/IGMPv2 membership report the kernel sets the
mrouters_only flag in a skb that may be a clone of the original skb, which
means that sometimes the bridge loses track of membership report packets (cb
buffers are tied to a specific skb and not shared) and it ends up forwading
join requests to the bridge interface.

This can cause unexpected membership timeouts and intermitent/permanent loss
of connectivity as described in RFC 4541 [2.1.1. IGMP Forwarding Rules]:

    A snooping switch should forward IGMP Membership Reports only to
    those ports where multicast routers are attached.
    [...]
    Sending membership reports to other hosts can result, for IGMPv1
    and IGMPv2, in unintentionally preventing a host from joining a
    specific multicast group.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Tested-by: Hayato Kakuta <kakuta.hayato@oss.ntt.co.jp>
Signed-off-by: David S. Miller <davem@conan.davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/bridge/br_multicast.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 2f14eafdeeab..a6d87c17bb03 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1424,7 +1424,7 @@ static int br_multicast_ipv4_rcv(struct net_bridge *br,
 	switch (ih->type) {
 	case IGMP_HOST_MEMBERSHIP_REPORT:
 	case IGMPV2_HOST_MEMBERSHIP_REPORT:
-		BR_INPUT_SKB_CB(skb2)->mrouters_only = 1;
+		BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
 		err = br_ip4_multicast_add_group(br, port, ih->group);
 		break;
 	case IGMPV3_HOST_MEMBERSHIP_REPORT: