On 26/08/14 21:47, Tom Herbert wrote: > Remote checksum offload is intended to be used to get checksum offload > of encapsulated packets to work with legacy NICs (those that don't > understand encapsulation protocols). I will be posting an > implementation to Linux shortly for GUE and/or Geneve.
This one was floated on the mailing list during the IETF-89 (and immediately thereabouts) discussions around geneve, fixed/floating headers, etc a while back. We have had a working implementation for the GRE case for a while now (we have it in a limited release product based around UML in customer labs). I need to get around to contribute it upstream (in fact, I was going to work on the patchsets this week). The implementation for UDP based is trivial if you go for generic (not protocol specific) checksum options in the linux kernel stack - as discussed on the list 6 months ago. All you need is to implement the IP_HDRINCL option for UDP in the kernel so you can get to the checksum. After that you can use f.e. what we have contributed as a L2TPv3 direct-in-vNIC decaps driver for qemu (to ship in qemu-kvm 2.1) or the legacy socket driver and extend it to use this option. A. > > Thanks, > Tom > > ---------- Forwarded message ---------- > From: <[email protected]> > Date: Tue, Aug 26, 2014 at 1:39 PM > Subject: New Version Notification for draft-herbert-remotecsumoffload-00.txt > To: Tom Herbert <[email protected]> > > > > A new version of I-D, draft-herbert-remotecsumoffload-00.txt > has been successfully submitted by Tom Herbert and posted to the > IETF repository. > > Name: draft-herbert-remotecsumoffload > Revision: 00 > Title: Remote checksum offload for encapsulation > Document date: 2014-08-27 > Group: Individual Submission > Pages: 9 > URL: > http://www.ietf.org/internet-drafts/draft-herbert-remotecsumoffload-00.txt > Status: > https://datatracker.ietf.org/doc/draft-herbert-remotecsumoffload/ > Htmlized: http://tools.ietf.org/html/draft-herbert-remotecsumoffload-00 > > > Abstract: > This specification describes remote checksum offload for > encapsulation, which is a mechanism that provides checksum offload of > encapsulated packets using rudimentary offload capabilities found in > most Network Interface Card (NIC) devices. The outer header checksum > (e.g. that in UDP or GRE) is enabled in packets and, with some > additional meta information, a receiver is able to deduce the > checksum to be set for an inner encapsulated packet. Effectively this > offloads the computation of the inner checksum. Enabling the outer > checksum in encapsulation has the additional advantage that it covers > more of the packet than the inner checksum including the > encapsulation headers. > > > > > Please note that it may take a couple of minutes from the time of submission > until the htmlized version and diff are available at tools.ietf.org. > > The IETF Secretariat > > _______________________________________________ > nvo3 mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/nvo3 > _______________________________________________ nvo3 mailing list [email protected] https://www.ietf.org/mailman/listinfo/nvo3
