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Date:   Sun, 17 Feb 2019 17:48:09 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Sebastian Gottschall <s.gottschall@newmedia-net.de>
Cc:     linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Ying Xu <yinxu@redhat.com>, Hangbin Liu <liuhangbin@gmail.com>,
        Nikolay Aleksandrov <nikolay@cumulusnetworks.com>,
        Roopa Prabhu <roopa@cumulusnetworks.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH 4.19 01/24] bridge: do not add port to router list when
 receives query with source 0.0.0.0
Message-ID: <20190217164809.GA24091@kroah.com>
References: <20181102182839.725385066@linuxfoundation.org>
 <20181102182839.913422845@linuxfoundation.org>
 <07d315a2-d735-3d8b-686c-9c52acf91bf1@newmedia-net.de>
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On Sun, Feb 17, 2019 at 03:29:22PM +0100, Sebastian Gottschall wrote:
> according to user reports this patch will cause a serious regression. igmp
> snooping is not working anymore with this patch
> 
> Am 02.11.2018 um 19:34 schrieb Greg Kroah-Hartman:
> > 4.19-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Hangbin Liu <liuhangbin@gmail.com>
> > 
> > [ Upstream commit 5a2de63fd1a59c30c02526d427bc014b98adf508 ]
> > 
> > Based on RFC 4541, 2.1.1.  IGMP Forwarding Rules
> > 
> >    The switch supporting IGMP snooping must maintain a list of
> >    multicast routers and the ports on which they are attached.  This
> >    list can be constructed in any combination of the following ways:
> > 
> >    a) This list should be built by the snooping switch sending
> >       Multicast Router Solicitation messages as described in IGMP
> >       Multicast Router Discovery [MRDISC].  It may also snoop
> >       Multicast Router Advertisement messages sent by and to other
> >       nodes.
> > 
> >    b) The arrival port for IGMP Queries (sent by multicast routers)
> >       where the source address is not 0.0.0.0.
> > 
> > We should not add the port to router list when receives query with source
> > 0.0.0.0.
> > 
> > Reported-by: Ying Xu <yinxu@redhat.com>
> > Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
> > Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
> > Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
> > Signed-off-by: David S. Miller <davem@davemloft.net>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > ---
> >   net/bridge/br_multicast.c |   10 +++++++++-
> >   1 file changed, 9 insertions(+), 1 deletion(-)
> > 
> > --- a/net/bridge/br_multicast.c
> > +++ b/net/bridge/br_multicast.c
> > @@ -1420,7 +1420,15 @@ static void br_multicast_query_received(
> >   		return;
> >   	br_multicast_update_query_timer(br, query, max_delay);
> > -	br_multicast_mark_router(br, port);
> > +
> > +	/* Based on RFC4541, section 2.1.1 IGMP Forwarding Rules,
> > +	 * the arrival port for IGMP Queries where the source address
> > +	 * is 0.0.0.0 should not be added to router port list.
> > +	 */
> > +	if ((saddr->proto == htons(ETH_P_IP) && saddr->u.ip4) ||
> > +	    (saddr->proto == htons(ETH_P_IPV6) &&
> > +	     !ipv6_addr_any(&saddr->u.ip6)))
> > +		br_multicast_mark_router(br, port);
> >   }
> >   static void br_ip4_multicast_query(struct net_bridge *br,

Is this also a problem in 4.20?  This patch went into 4.20-rc1, so it
has been around for a while with no reported issues that I can find.
Any pointers to the reports?

thanks,

greg k-h