> -----Original Message----- > From: Akhil Goyal [mailto:akhil.goyal at nxp.com] > Sent: Wednesday, October 19, 2016 1:38 AM > To: De Lara Guarch, Pablo; Gonzalez Monroy, Sergio; dev at dpdk.org > Subject: RE: [PATCH] examples/ipsec-secgw: Update checksum while > decrementing ttl > > > > -----Original Message----- > From: De Lara Guarch, Pablo [mailto:pablo.de.lara.guarch at intel.com] > Sent: Monday, October 17, 2016 10:35 PM > To: Gonzalez Monroy, Sergio <sergio.gonzalez.monroy at intel.com>; Akhil > Goyal <akhil.goyal at nxp.com>; dev at dpdk.org > Subject: RE: [PATCH] examples/ipsec-secgw: Update checksum while > decrementing ttl > > > > > -----Original Message----- > > From: Gonzalez Monroy, Sergio > > Sent: Monday, October 10, 2016 5:05 AM > > To: De Lara Guarch, Pablo; Akhil Goyal; dev at dpdk.org > > Subject: Re: [PATCH] examples/ipsec-secgw: Update checksum while > > decrementing ttl > > > > On 07/10/2016 21:53, De Lara Guarch, Pablo wrote: > > >> -----Original Message----- > > >> From: Akhil Goyal [mailto:akhil.goyal at nxp.com] > > >> Sent: Tuesday, October 04, 2016 11:33 PM > > >> To: De Lara Guarch, Pablo; Gonzalez Monroy, Sergio; dev at dpdk.org > > >> Subject: Re: [PATCH] examples/ipsec-secgw: Update checksum while > > >> decrementing ttl > > >> > > >> On 10/5/2016 6:04 AM, De Lara Guarch, Pablo wrote: > > >>> > > >>>> -----Original Message----- > > >>>> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Sergio > > Gonzalez > > >>>> Monroy > > >>>> Sent: Monday, September 26, 2016 6:28 AM > > >>>> To: akhil.goyal at nxp.com; dev at dpdk.org > > >>>> Subject: Re: [dpdk-dev] [PATCH] examples/ipsec-secgw: Update > > checksum > > >>>> while decrementing ttl > > >>>> > > >>>> Hi Akhil, > > >>>> > > >>>> This application relies on checksum offload in both outbound and > > >> inbound > > >>>> paths (PKT_TX_IP_CKSUM flag). > > >> [Akhil]Agreed that the application relies on checksum offload, but > > >> here we are talking about the inner ip header. Inner IP checksum > > >> will be updated on the next end point after decryption. This would > > >> expect that the next end point must have checksum offload > > >> capability. What if we are capturing the encrypted packets on > > >> wireshark or say send it to some other machine which does not run > > >> DPDK and do not know about > > checksum > > >> offload, then wireshark/other machine will not be able to get the > > >> correct the checksum and will show error. > > > > Understood, we need to have a valid inner checksum. > > RFC1624 states that the computation would be incorrect in > > corner/boundary case. > > I reckon you are basing your incremental update on RFC1141? > > > > Also I think you should take care of endianess and increment the > > checksum with > > host_to_be(0x0100) instead of +1. > > > > >>>> Because we assume that we always forward the packet in both > > >>>> paths, > > we > > >>>> decrement the ttl in both inbound and outbound. > > >>>> You seem to only increment (recalculate) the checksum of the > > >>>> inner IP header in the outbound path but not the inbound path. > > >> [Akhil]Correct I missed out the inbound path. > > >>>> Also, in the inbound path you have to consider a possible ECN > > >>>> value > > >> update. > > >> [Akhil]If I take care of the ECN then it would mean I need to > > >> calculate the checksum completely, incremental checksum wont give > correct results. > > >> This would surely impact performance. Any suggestion on how should > > >> we take care of ECN update. Should I recalculate the checksum and > > >> send the patch for ECN update? Or do we have a better solution. > > > > If I am understanding the RFCs mentioned above correctly, you should > > be able to do incremental checksum update for any 16bit field/value of > > the IP header. > > I don't see no reason why you couldn't do something like that, except > > that you would have to follow the full equation instead of just adding > > 0x0100, which would be always the case when decrementing TTL. > > > > What do you think? > > Any comments, Akhil? > > Ok.. will send next version soon.
Hi Akhil, Are you sending that version soon? It won't make it the RC2, but it may be merged for RC3. Thanks, Pablo