WAS ( Re: [PATCH net-next 1/1] net_sched: Introduce skbmod action

On 16-07-19 08:23 PM, Daniel Borkmann wrote:

On 07/19/2016 08:04 PM, Cong Wang wrote:

quoted

On Tue, Jul 19, 2016 at 8:03 AM, Daniel Borkmann
[off-list ref] wrote:

quoted

On 07/19/2016 03:56 PM, Jamal Hadi Salim wrote:
[...]

[..]

quoted

I don't think so. 1) checksum is supposed to be done by csum action
rather than pedit (or skbmod if it matters), 2) csum action currently
already handles that correctly for both egress and ingress: 2a)
CHECKSUM_COMPLETE is meaningless on egress; 2b) it forces
CHECKSUM_COMPLETE to be CHECKSUM_NONE on ingress
and it is correctly respected.

Ahh, right, so it redoes entire csums when worst-case changing one byte
only, since it cannot know what other actions like pedit did previously.

 >

But it also means for your l2 mac addr changes to force a CHECKSUM_COMPLETE
into CHECKSUM_NONE with csum action that you need to call into one of the
l3/l4 helpers as far as I see.

Forgot about csum which would work with pedit - didnt quiet parse what
you are saying above though:
does changing MAC address require changing to CHECKSUM_NONE? If yes,
then seems like i need to send a patch for act_ife as well to make in
the spirit of mirred?

Having said all that:
This discussion now has gone past the original patch submission.
I really want to see this patch go in and dont want to get Dave to
review all these side comments - for this reason I changed the subject.

cheers,
jamal