[ovs-dev] [Patch] datapath: fix checksum after putting vlan tag

Cong Wang amwang at redhat.com
Wed Feb 27 02:46:32 UTC 2013


On Tue, 2013-02-26 at 12:51 -0800, Jesse Gross wrote:
> On Tue, Feb 26, 2013 at 1:46 AM, Cong Wang <amwang at redhat.com> wrote:
> > After inserting the VLAN tag with __vlan_put_tag(), we should
> > re-calculate the skb checksum if it is done.
> >
> > Cc: Jesse Gross <jesse at nicira.com>
> > Signed-off-by: Cong Wang <amwang at redhat.com>
> 
> This code path is supposed to be emulate dev_hard_start_xmit() on
> older kernels.  However, the current upstream code doesn't have the
> behavior that you are proposing because CHECKSUM_COMPLETE is generally
> not significant on the transmit path (it seems only likely to be
> useful if a packet is looped back through something like a veth).  At
> the very least, the behavior of the upstream and backported versions
> should match.

Makes sense!

Thanks, Jesse.




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