[ovs-dev] [PATCH v3 2/2] netdev-linux: Read packet auxdata to obtain vlan_tid

[Simon Horman]

On Tue, Dec 17, 2013 at 05:08:35PM -0800, Ben Pfaff wrote:
> On Mon, Dec 16, 2013 at 05:57:52PM +0900, Simon Horman wrote:
> > If VLAN acceleration is used when the kernel receives a packet
> > then the outer-most VLAN tag will not be present in the packet
> > when it is received by netdev-linux. Rather, it will be present
> > in auxdata.
> > 
> > This patch uses recvmsg() instead of recv() to read auxdata for
> > each packet and if the vlan_tid is set then it is added to the packet.
> > 
> > Adding the vlan_tid makes use of headroom available
> > in the buffer parameter of rx_recv.
> > 
> > Signed-off-by: Simon Horman <horms at verge.net.au>
> 
> This patch should be Linux-specific, why does it update netdev-bsd?

Sorry, that portion should have gone into the previous patch.

> I think we should add a comment to netdev_rx_recv() explaining how the
> tailroom in the buffer may get used (you might need 4 bytes more
> tailroom than the actual MTU, and you might get 4 bytes of extra
> headroom in the result).

Sure.