Re: [PATCH 4.19 01/24] bridge: do not add port to router list when receives query with source 0.0.0.0

[Sebastian Gottschall]

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@xxxxxxxxx>
>
> [ 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@xxxxxxxxxx>
> Signed-off-by: Hangbin Liu <liuhangbin@xxxxxxxxx>
> Acked-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx>
> Acked-by: Roopa Prabhu <roopa@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
>   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,