[ovs-dev] vlan_deaccel_tag() and checksum

Ben Pfaff blp at nicira.com
Tue Feb 22 22:43:26 UTC 2011


On Tue, Feb 22, 2011 at 02:13:06PM -0800, Jesse Gross wrote:
> On Thu, Feb 17, 2011 at 10:44 AM, Ben Pfaff <blp at nicira.com> wrote:
> > It seems to me that vlan_deaccel_tag() needs to increase csum_start by
> > 4 in the CHECKSUM_PARTIAL case, something like this following.  I
> > don't see anything like this in the other callers of __vlan_put_tag(),
> > but it looks like most of those wouldn't have CHECKSUM_PARTIAL skbs
> > anyway.
> >
> > Does this seem correct to you?
> 
> This shouldn't be necessary because csum_start is relative to
> skb->head not skb->data, so you can push and pop headers on the front
> of the packet without having to update it.

OK.

> Are you seeing problems?

At one point I was investigating this as the problem possibly behind
what I actually fixed with "datapath: Properly initialize ovs_skb_cb of
packet from userspace."  So no, we can drop this.




More information about the dev mailing list