From: Fernando Luis Vázquez Cao <ferna...@oss.ntt.co.jp>
commit 62b2bcb49cca72f6d3f39f831127a6ab315a475d upstream.
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 <ferna...@oss.ntt.co.jp>
Tested-by: Hayato Kakuta <kakuta.hay...@oss.ntt.co.jp>
Signed-off-by: David S. Miller <da...@conan.davemloft.net>
---
diff -urNp linux-2.6.35.13-orig/net/bridge/br_multicast.c
linux-2.6.35.13/net/bridge/br_multicast.c
--- linux-2.6.35.13-orig/net/bridge/br_multicast.c 2011-04-29
00:21:24.000000000 +0900
+++ linux-2.6.35.13/net/bridge/br_multicast.c 2011-07-28 10:28:08.505872639
+0900
@@ -1403,7 +1403,7 @@ static int br_multicast_ipv4_rcv(struct
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:
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