Linux Ethernet Bridging - Sep 2017 - [Bridge] Problem with syslog in bridge(?) with ethernet broadcast packets with QinQ

Hi all,

I'm facing some problem with ethernet multicast traffic and QinQ
(802.3q in both tags) in -apparently- a bridge in Ubuntu 16.04
(4.12.0-041200-generic).

My set up is the following:
+-----------+
|     VM    |
+-----+-----+
      |
      | tag 55
+---------+------------+
|        OVS           |
+-----------+----------+
                | veth3.9
veth3   +  |
     +--+
     | veth2
+-------+----------+
|       BRIDGE     |
+-------+----------+
     |
     |
+-------+----------+
|      ens11f1     |
+------------------+


I am setting the inner tag with OVS and the outer tag with a vlan type veth.
The problem I have is that every packet sent from the VM to Ethernet
broadcast addresses (33:33:xx:xx:xx:xx) generates a "IPv6 header not
found" entry in syslog.

If I generate a 'ens11f1.9' interface and remove the BRIDGE, the log
entry dissapears.

Some questions:
* Is there any problem with these packets (ethernet multicast with
QinQ) in bridges?
* Is there any configuration I should change for the problem to dissapear?

Thanks in advance for your help! Any hint about what could be
generating those logs is appreciated.

Regards,
Andr?s Pozo

On Mon, 18 Sep 2017 17:21:11 +0200
Andr?s Pozo Mu?oz <andres.pozom at gmail.com> wrote:
> Hi all,
> 
> I'm facing some problem with ethernet multicast traffic and QinQ
> (802.3q in both tags) in -apparently- a bridge in Ubuntu 16.04
> (4.12.0-041200-generic).
> 
> My set up is the following:
> +-----------+
> |     VM    |
> +-----+-----+
>       |
>       | tag 55
> +---------+------------+
> |        OVS           |
> +-----------+----------+
>                 | veth3.9
> veth3   +  |
>      +--+
>      | veth2
> +-------+----------+
> |       BRIDGE     |
> +-------+----------+
>      |
>      |
> +-------+----------+
> |      ens11f1     |
> +------------------+
> 
> 
> I am setting the inner tag with OVS and the outer tag with a vlan type
veth.
> The problem I have is that every packet sent from the VM to Ethernet
> broadcast addresses (33:33:xx:xx:xx:xx) generates a "IPv6 header not
> found" entry in syslog.
> 
> If I generate a 'ens11f1.9' interface and remove the BRIDGE, the
log
> entry dissapears.
> 
> Some questions:
> * Is there any problem with these packets (ethernet multicast with
> QinQ) in bridges?
> * Is there any configuration I should change for the problem to dissapear?
> 
> Thanks in advance for your help! Any hint about what could be
> generating those logs is appreciated.
> 
> Regards,
> Andr?s Pozo
Where is the log message coming from? Could you change the printk into
a WARN_ON_ONCE and get backtrace? My guess is the firewall code doesn't
understand the additional tag.