[Bridge] Problem with syslog in bridge(?) with ethernet broadcast packets with QinQ

[Bridge] Problem with syslog in bridge(?) with ethernet broadcast packets with QinQ

[Andrés Pozo Muñoz]

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,
Andrés Pozo

Re: [Bridge] Problem with syslog in bridge(?) with ethernet broadcast packets with QinQ

[Stephen Hemminger]

On Mon, 18 Sep 2017 17:21:11 +0200
Andrés Pozo Muñoz <andres.pozom@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,
> Andrés 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.

Re: [Bridge] Problem with syslog in bridge(?) with ethernet broadcast packets with QinQ

[Andrés Pozo Muñoz]

Hi Stephen,

thanks for your response.

I managed to move forward removing the bridge from my schema. I think
the problem has to deal with multicast IPv6 addresses with QinQ in a
bridge.

If I remove that bridge and put the traffic through a vlan type
subinterface in the physical interface, everything seems to work fine
(and the syslog entry, no longer appears...).

I'll try to follow your suggestion and get that trace....

Thanks!
Regards,
Andres


On Thu, Oct 12, 2017 at 4:58 PM, Stephen Hemminger
<stephen@networkplumber.org> wrote:
> On Mon, 18 Sep 2017 17:21:11 +0200
> Andrés Pozo Muñoz <andres.pozom@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,
>> Andrés 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.