| Message ID | 1308013618.3896.11.camel@nexus.oss.ntt.co.jp |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Fernando Luis Vázquez Cao <fernando@oss.ntt.co.jp> Date: Tue, 14 Jun 2011 10:06:58 +0900 > 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> Applied. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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; }
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> --- -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html