>>
>> The mlx5 hardware requires the outer UDP checksum is not set when offloading
>> encapsulated packets.
>
>The Intel documentation said the same thing. That was due to the fact
>that the hardware didn't computer the outer UDP header checksum. I
>suspect the Mellanox hardware has the same issue. Also I have tested
>on a ConnectX-4 board with the latest firmware and what I am seeing is
>that with my patches applied the outer checksum is being correctly
>applied for segmentation offloads.
>
>My thought is that that the hardware appears to ignore the UDP
>checksum so if it is non-zero you cannot guarantee the checksum would
>be correct on the last frame if it is a different size than the rest
>of the segments. In the case of these patches that issue has been
>resolved as I have precomputed the UDP checksum for the outer UDP
>header and all of the segments will be the same length so there should
>be no variation in the UDP checksum of the outer header. Unless you
>can tell my exactly the reason why we cannot provide the outer UDP
>checksum I would assume that the reason is due to the fact that the
>hardware doesn't compute it so you cannot handle a fragment on the end
>which is resolved already via GSO_PARTIAL.
I will check internally and verify there are no unforeseen issues with setting
the outer UDP checksum in this scenario.
>
>- Alex
