Re: [PATCH net-next 6/8] net: gre: Implement LCO for GRE over IPv4

On 11/01/16 18:39, Alexander Duyck wrote:

On Mon, Jan 11, 2016 at 5:21 AM, Edward Cree [off-list ref] wrote:

quoted

csum_fold complements, so if the sum comes to (say) 0x1fffe, it will return ~0xffff which is 0.

Next version of patch will mangle 0 for both branches.

Actually you may want to go the other way on that.  If they weren't
flipping the checksum value for GRE before why should we start doing
that now?  I'm pretty sure the checksum mangling is a very UDP centric
thing.  There is no need to introduce it to other protocols.

Good catch, you're quite right.

-ed