Re: [Bridge] Bridging untagged and tagged VLANs

[Michael Tremer <michael.tremer@ipfire.org>]

Oops, just sent the email when your one scrabbled to my inbox.

https://lists.linux-foundation.org/pipermail/bridge/2009-July/006626.html

I applied that ebtables rule to the chain but no packages got to the 
vlan interface (eth0.30) anymore.

Michael


Nicolas de Pesloüan wrote:
> Michael Tremer wrote:
>>
>> In this mail on
>> http://www.mail-archive.com/bridge@lists.osdl.org/msg01440.html
>> there is the following sentence: "- Add native support for an untagged
>> vlan.  Currently an untagged vlan can be implimented using ebtables or
> > similar."
>>
>> Do you know how to do this?
>
> For as far as I remember, the right way to do it with ebtables is :
>
> brctl addbr br0
> vconfig add eth0 30
> brctl addif br0 eth0.30
> brctl addif br0 eth0
>
> ebtables --table broute -A BROUTING --protocol 802_1Q --vlan-id 30 
> --jump DROP
>
> Normally, a DROP target in BROUTING let the frame being ROUTED. The 
> exact behavior  is "give it to upper layer", which is IP in most case. 
> But, for a 802.1q tagged frame, the upper layer is "remove the 802.1q 
> header and give it again to lower layer, on the right interface".
>
> So this ebtables entry deny the bridge the opportunity to eat frames 
> having a 802.1q vlan id = 30, giving the opportunity to the vlan stack 
> to remove the vlan header and give it to eth0.30...
>
> Not tested, because I don't have a bridge available right now, but 
> this should work.
>
> Of course, if you add several eth0.X interfaces to the bridge, you 
> should add the corresponding ebtables entry. For very special 
> configuration, --in-interface eth0 might be necessary too.
>
> Just thinking about it, the --vlan-id 30 might be useless. Juste 
> having --protocol 802_1Q might be enough for simple configuration. 
> Just try and told us.
>
> HTH.
>
>     Nicolas.