[dpdk-dev] about rx checksum flags

Stephen Hemminger stephen at networkplumber.org
Tue May 31 22:28:20 CEST 2016


On Tue, 31 May 2016 21:11:59 +0200
Olivier MATZ <olivier.matz at 6wind.com> wrote:

> 
> 
> On 05/31/2016 10:09 AM, Yuanhan Liu wrote:
> > On Mon, May 30, 2016 at 05:26:21PM +0200, Olivier Matz wrote:
> >>  PKT_RX_L4_CKSUM_NONE: the L4 checksum is not correct in the packet
> >>  data, but the integrity of the L4 header is verified.
> >>   -> the application can process the packet but must not verify the
> >>      checksum by sw. It has to take care to recalculate the cksum
> >>      if the packet is transmitted (either by sw or using tx offload)
> > 
> > I like the explanation you made at [1] better :)
> > 
> > So in general, I think this proposal is good to have.
> 
> Thanks everyone for your feedback.
> 
> I'll try to send a first patch proposition soon.
> 
> Regards,
> Olivier

I think it is time to ditch the old definitions of Rx checksum and instead
use something more compatiable with virtio (and Linux). I.e have three values
  1) checksum is know good for packet contents
  2) checksum value one's complement for packet contents
  3) checksum is undetermined
The original definition seems to be Intel HW centric and applies to a limited
range of devices making it unusable by general application.

Break the ABI, and ditch the old values (ok mark PKT_RX_L4_CKSUM_BAD as __deprecated
and remove all usage).


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