[ovs-discuss] pf_packet/af_packet socket with vlan tagging does not strip vlan tag

[Jon Gainsley]

Hi Ben,

Thanks for your response. Yeah, that's exactly it. I tracked it down to
pop_vlan(), which was not popping the vlan because skb->protocol was set to
ETH_P_ALL, rather than ETH_P_8021Q. The reason it works on the first few
packets is without a rule, the packet is upcalled, which clones skb and
properly assigns skb->protocol by parsing the packet.

If it's a kernel bug, it's not fixed in 3.16. I've modified
datapath/actions.c:pop_vlan to check the packet's eth proto and set
skb->protocol to ETH_P_8021Q if that's what's in the packet, so the vlan
gets popped correctly. I don't know if you have any comments on if that's a
valid workaround, but it's what I'm going to try for now and see how it
goes.

Thanks!
-Jon



On Tue, May 26, 2015 at 6:22 PM, Ben Pfaff <blp at nicira.com> wrote:

> On Wed, May 20, 2015 at 01:45:37PM -0700, Jon Gainsley wrote:
> > Hi,
> >
> > I'm wondering if anyone can help me with this. I am having trouble
> > inserting raw vlan tagged packets into the vswitch using an AF_PACKET
> > socket. I have the following simple bridge:
>
> This kind of sounds like this kernel bug described in the thread here:
>         http://openvswitch.org/pipermail/dev/2011-December/013948.html
>
> I don't know whether it's been fixed.
>
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