[ovs-dev] [PATCH] netdev implementation for FreeBSD

[Ben Pfaff]

On Tue, Jul 10, 2012 at 09:23:05AM -0400, Ed Maste wrote:
> >> It isn't clear to me though why the Linux userspace mode does not behave
> >> the same way though.  I had a (very) brief look at the way PF_PACKET is
> >> handled in Linux and it seemed like the packet would still be passed up
> >> the stack -- there must be something else that I'm missing.
> >
> > Linux appears to have a special case such that a packet will never be
> > delivered back to the socket from which it originates via the network
> > tap interface, see dev_queue_xmit_nit() in net/core/dev.c:
> 
> That looks to me like it should address the transmit case, avoiding
> duplicate handling of a packet transmitted by Open vSwitch - I don't
> see how the receive case (from the physical network) is handled.

Probably there's just a bug there.  The userspace version isn't the
primary way to use Open vSwitch with a Linux kernel so it gets little
testing.