netdev - Re: [PATCH net] Bridge: Fix ipv6 mc snooping if bridge has no ipv6 address

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Date:	Tue, 28 Jun 2016 08:04:42 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	linus.luessing@...3.blue
Cc:	daniel@...wrt.com, bridge@...ts.linux-foundation.org,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	stephen@...workplumber.org, uw@...do.com, ulrich.weber@...hos.com
Subject: Re: [PATCH net] Bridge: Fix ipv6 mc snooping if bridge has no ipv6
 address

From: Linus Lüssing <linus.luessing@...3.blue>
Date: Sat, 25 Jun 2016 16:20:28 +0200

> On Fri, Jun 24, 2016 at 12:35:18PM +0200, Daniel Danzberger wrote:
>> The bridge is falsly dropping ipv6 mulitcast packets if there is:
>>  1. No ipv6 address assigned on the brigde.
>>  2. No external mld querier present.
>>  3. The internal querier enabled.
>> 
>> When the bridge fails to build mld queries, because it has no
>> ipv6 address, it slilently returns, but keeps the local querier enabled.
>> This specific case causes confusing packet loss.
>> 
>> Ipv6 multicast snooping can only work if:
>>  a) An external querier is present
>>  OR
>>  b) The bridge has an ipv6 address an is capable of sending own queries
>> 
>> Otherwise it has to forward/flood the ipv6 multicast traffic,
>> because snooping cannot work.
>> 
>> This patch fixes the issue by adding a flag to the bridge struct that
>> indicates that there is currently no ipv6 address assinged to the bridge
>> and returns a false state for the local querier in
>> __br_multicast_querier_exists().
> 
> Fixes: 1d81d4c3dd88 ("bridge: check return value of ipv6_dev_get_saddr()")

You're missing an initial 'd' in that SHA1-ID.

With that fixed, applied and queued up for -stable.