From: Stephen Hemminger <shemminger@vyatta.com>
To: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
netdev@vger.kernel.org,
Hayato Kakuta <kakuta.hayato@oss.ntt.co.jp>
Subject: Re: IGMP snooping: set mrouters_only flag for IPv4 traffic properly
Date: Tue, 14 Jun 2011 13:22:12 -0400 [thread overview]
Message-ID: <20110614132212.2ac83c6c@s6510.ftrdhcpuser.net> (raw)
In-Reply-To: <1307934163.3550.2.camel@nausicaa>
On Mon, 13 Jun 2011 12:02:43 +0900
Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> wrote:
> 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 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 <fernando@oss.ntt.co.jp>
> Tested-by: Hayato Kakuta <kakuta.hayato@oss.ntt.co.jp>
> ---
>
> 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 2011-06-09 13:34:04.164261031 +0900
> +++ linux-3.0-rc2/net/bridge/br_multicast.c 2011-06-09 20:04:23.473930447 +0900
> @@ -1424,7 +1424,7 @@ 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:
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
next prev parent reply other threads:[~2011-06-14 17:22 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-13 2:59 [PATCH 0/2] IGMP snooping: set mrouters_only flag properly Fernando Luis Vazquez Cao
2011-06-13 3:02 ` IGMP snooping: set mrouters_only flag for IPv4 traffic properly Fernando Luis Vazquez Cao
2011-06-14 17:22 ` Stephen Hemminger [this message]
2011-06-15 5:09 ` Fernando Luis Vázquez Cao
2011-06-13 3:21 ` [PATCH 2/2] IGMP snooping: set mrouters_only flag for IPv6 " Fernando Luis Vazquez Cao
2011-06-14 1:01 ` [PATCH 0/2] IGMP snooping: set mrouters_only flag properly Fernando Luis Vázquez Cao
2011-06-14 1:04 ` [PATCH 1/2] IGMP snooping: set mrouters_only flag for IPv4 traffic properly Fernando Luis Vázquez Cao
2011-06-17 3:14 ` David Miller
2011-06-17 4:39 ` Fernando Luis Vazquez Cao
2011-06-14 1:06 ` [PATCH 2/2] IGMP snooping: set mrouters_only flag for IPv6 " Fernando Luis Vázquez Cao
2011-06-17 3:14 ` David Miller
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