Linux Ethernet Bridging - Feb 2019 - [Bridge] [PATCH net] Revert "bridge: do not add port to router list when receives query with source 0.0.0.0"

This reverts commit 5a2de63fd1a5 ("bridge: do not add port to router list
when receives query with source 0.0.0.0") and commit 0fe5119e267f
("net:
bridge: remove ipv6 zero address check in mcast queries")

The reason is RFC 4541 is not a standard but suggestive. Currently we
will elect 0.0.0.0 as Querier if there is no ip address configured on
bridge. If we do not add the port which recives query with source
0.0.0.0 to router list, the IGMP reports will not be about to forward
to Querier, IGMP data will also not be able to forward to dest.

As Nikolay suggested, revert this change first and add a boolopt api
to disable none-zero election in future if needed.

Reported-by: Linus L?ssing <linus.luessing at c0d3.blue>
Reported-by: Sebastian Gottschall <s.gottschall at newmedia-net.de>
Fixes: 5a2de63fd1a5 ("bridge: do not add port to router list when receives
query with source 0.0.0.0")
Fixes: 0fe5119e267f ("net: bridge: remove ipv6 zero address check in mcast
queries")
Signed-off-by: Hangbin Liu <liuhangbin at gmail.com>
---
 net/bridge/br_multicast.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 3aeff0895669..ac92b2eb32b1 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1204,14 +1204,7 @@ static void br_multicast_query_received(struct net_bridge
*br,
 		return;
 
 	br_multicast_update_query_timer(br, query, max_delay);
-
-	/* 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))
-		br_multicast_mark_router(br, port);
+	br_multicast_mark_router(br, port);
 }
 
 static void br_ip4_multicast_query(struct net_bridge *br,
-- 
2.19.2

On 22/02/2019 15:22, Hangbin Liu wrote:
> This reverts commit 5a2de63fd1a5 ("bridge: do not add port to router
list
> when receives query with source 0.0.0.0") and commit 0fe5119e267f
("net:
> bridge: remove ipv6 zero address check in mcast queries")
> 
> The reason is RFC 4541 is not a standard but suggestive. Currently we
> will elect 0.0.0.0 as Querier if there is no ip address configured on
> bridge. If we do not add the port which recives query with source
> 0.0.0.0 to router list, the IGMP reports will not be about to forward
> to Querier, IGMP data will also not be able to forward to dest.
> 
> As Nikolay suggested, revert this change first and add a boolopt api
> to disable none-zero election in future if needed.
> 
> Reported-by: Linus L?ssing <linus.luessing at c0d3.blue>
> Reported-by: Sebastian Gottschall <s.gottschall at newmedia-net.de>
> Fixes: 5a2de63fd1a5 ("bridge: do not add port to router list when
receives query with source 0.0.0.0")
> Fixes: 0fe5119e267f ("net: bridge: remove ipv6 zero address check in
mcast queries")
> Signed-off-by: Hangbin Liu <liuhangbin at gmail.com>
> ---
>  net/bridge/br_multicast.c | 9 +--------
>  1 file changed, 1 insertion(+), 8 deletions(-)
> 
Thank you. Unfortunately we made a mistake and have to fix compatibility with
the current bridges. As noted in the commit message if this is needed it can
be added as optional behaviour with default off so we don't break any
setups.

Acked-by: Nikolay Aleksandrov <nikolay at cumulusnetworks.com>

From: Hangbin Liu <liuhangbin at gmail.com>
Date: Fri, 22 Feb 2019 21:22:32 +0800
> This reverts commit 5a2de63fd1a5 ("bridge: do not add port to router
list
> when receives query with source 0.0.0.0") and commit 0fe5119e267f
("net:
> bridge: remove ipv6 zero address check in mcast queries")
> 
> The reason is RFC 4541 is not a standard but suggestive. Currently we
> will elect 0.0.0.0 as Querier if there is no ip address configured on
> bridge. If we do not add the port which recives query with source
> 0.0.0.0 to router list, the IGMP reports will not be about to forward
> to Querier, IGMP data will also not be able to forward to dest.
> 
> As Nikolay suggested, revert this change first and add a boolopt api
> to disable none-zero election in future if needed.
> 
> Reported-by: Linus L?ssing <linus.luessing at c0d3.blue>
> Reported-by: Sebastian Gottschall <s.gottschall at newmedia-net.de>
> Fixes: 5a2de63fd1a5 ("bridge: do not add port to router list when
receives query with source 0.0.0.0")
> Fixes: 0fe5119e267f ("net: bridge: remove ipv6 zero address check in
mcast queries")
> Signed-off-by: Hangbin Liu <liuhangbin at gmail.com>
Applied and queued up for -stable, thanks.