[Bridge] Can linux kernel bridge forward 802.1q tagged vlan packets?

[Stephan von Krawczynski]

On Thu, 22 Aug 2013 15:19:41 -0700
Stephen Hemminger <stephen at networkplumber.org> wrote:

> On Thu, 22 Aug 2013 23:49:41 +0200
> Marek Kierdelewicz <marek at piasta.pl> wrote:
> 
> > Hi,
> > 
> > >My general idea is to bridge tagged vlan packets from a physical
> > >interface (intel) to a virtual interface (virtio in qemu) and not
> > >losing the tags, so the qemu guest can use vconfig and friends to get
> > >some vlan interfaces. Is this possible and are there any additional
> > >steps necessary besides the usual bridge configuration?
> > 
> > I'm using this setup with KVM virtualization (Qemu's successor). It
> > didn't work with default nic type for guest (realtek I think) as 802.1q
> > tags were not preserved properly in one of the directions. I don't
> > remember specifics. Anyway using e1000 driver instead of default fixed
> > it. Works like a charm.
> 
> KVM e1000 Vnic doesn't do VLAN offloading at least in my experience.
> Virtio works fine.

Ok guys, here is one of the major questions in this issue:

How did you manage to convince the _host_ interface driver (in my setup "igb"
from intel) to get the vlan tagged packets from the LAN port. igb has a vlan
filter function built in and reads _no_ tagged packets at all if the driver
does not tell it to. And in case of "up-ing" the interface for attachment to a
bridge it does not configure this vlan filter.
How is this expected to work?

-- 
Regards,
Stephan