> -----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. > >> > >> 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. > > > > Any further comments here, Akhil? > > > > Thanks, > > Pablo > > > [Akhil] Sorry I missed out the previous reply from Sergio.
Any more comments, Sergio? Pablo > > Thanks, > Akhil > >>
