IGMP snooping: set mrouters_only flag for IPv6 traffic properly
Upon reception of a MGM report packet the kernel sets the mrouters_only flag
in a skb that is a clone of the original skb, which means that the bridge
loses track of MGM 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>
Signed-off-by: David S. Miller <davem@conan.davemloft.net>
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index a6d87c1..29b9812 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1543,7 +1543,7 @@
goto out;
}
mld = (struct mld_msg *)skb_transport_header(skb2);
- BR_INPUT_SKB_CB(skb2)->mrouters_only = 1;
+ BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
err = br_ip6_multicast_add_group(br, port, &mld->mld_mca);
break;
}