From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus =?utf-8?Q?L=C3=BCssing?= Subject: Re: [PATCH net] Bridge: Fix ipv6 mc snooping if bridge has no ipv6 address Date: Sat, 25 Jun 2016 16:20:28 +0200 Message-ID: <20160625142028.GF4407@otheros> References: <1466764518-11358-1-git-send-email-daniel@dd-wrt.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: netdev@vger.kernel.org, bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Ulrich Weber , Ulrich Weber , davem@davemloft.net To: Daniel Danzberger Return-path: Content-Disposition: inline In-Reply-To: <1466764518-11358-1-git-send-email-daniel@dd-wrt.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: bridge-bounces@lists.linux-foundation.org Errors-To: bridge-bounces@lists.linux-foundation.org List-Id: netdev.vger.kernel.org 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()")