From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fernando Luis Vazquez Cao Subject: [PATCH 2/2] IGMP snooping: set mrouters_only flag for IPv6 traffic properly Date: Mon, 13 Jun 2011 12:21:44 +0900 Message-ID: <1307935304.3550.8.camel@nausicaa> References: <1307933995.2704.11.camel@nausicaa> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Stephen Hemminger , netdev@vger.kernel.org, Hideaki YOSHIFUJI To: Herbert Xu Return-path: Received: from serv2.oss.ntt.co.jp ([222.151.198.100]:42604 "EHLO serv2.oss.ntt.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752891Ab1FMDVq (ORCPT ); Sun, 12 Jun 2011 23:21:46 -0400 In-Reply-To: <1307933995.2704.11.camel@nausicaa> Sender: netdev-owner@vger.kernel.org List-ID: 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 specifici 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 --- diff -urNp linux-3.0-rc2-orig/net/bridge/br_multicast.c linux-3.0-rc2/net/bridge/br_multicast.c --- linux-3.0-rc2-orig/net/bridge/br_multicast.c 2011-06-13 12:10:27.805554187 +0900 +++ linux-3.0-rc2/net/bridge/br_multicast.c 2011-06-13 12:12:27.591626915 +0900 @@ -1543,7 +1543,7 @@ static int br_multicast_ipv6_rcv(struct 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; }