Messages in this thread Patch in this message | | | Subject | [STABLE] [PATCH] IGMP snooping: set mrouters_only flag for IPv4 traffic properly | From | Fernando Luis Vazquez Cao <> | Date | Thu, 28 Jul 2011 10:53:30 +0900 |
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From: Fernando Luis Vázquez Cao <fernando@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 <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> ---
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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