[ovs-dev] [PATCH] datapath: Better handle vlan packets sent to userspace.

[Ben Pfaff]

On Thu, Nov 17, 2011 at 04:05:00PM -0800, Jesse Gross wrote:
> We no longer clone packets that are sent via the userspace action
> because placing them in Netlink attributes makes a copy so we
> generally don't touch the original.  The one exception to this is
> accelerated vlan tags, which are currently inserted into the
> original packet as long as it isn't cloned.  Although the clone
> check prevents us from causing problems for past packets it has
> issues for future processing:
> 
>  * It turns accelerated tags into non-accelerated tags.  This isn't
>    inherently a problem but some cards may not properly support
>    offloads with in-band tags.
>  * It doesn't update CHECKSUM_COMPLETE if there is one.
>  * If the operation fails, it will free the packet resulting in a
>    later use-after-free.
> 
> This patch fixes the above issues with a conservative approach.
> It's possible to do it more efficiently but it probably doesn't
> matter in most cases.
> 
> Signed-off-by: Jesse Gross <jesse at nicira.com>

Acked-by: Ben Pfaff <blp at nicira.com>