From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Berg Subject: Re: IPv6-UDP 0x0000 checksum Date: Thu, 26 Jan 2017 15:49:24 +0100 Message-ID: <1485442164.14760.11.camel@sipsolutions.net> References: <1485437276.14760.3.camel@sipsolutions.net> <1485438299.5145.117.camel@edumazet-glaptop3.roam.corp.google.com> (sfid-20170126_144502_343976_16232A6D) <1485438546.14760.7.camel@sipsolutions.net> <1485441942.5145.131.camel@edumazet-glaptop3.roam.corp.google.com> (sfid-20170126_154545_190303_B1FB80BF) Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-wireless To: Eric Dumazet Return-path: In-Reply-To: <1485441942.5145.131.camel-XN9IlZ5yJG9HTL0Zs8A6p+yfmBU6pStAUsxypvmhUTTZJqsBc5GL+g@public.gmane.org> (sfid-20170126_154545_190303_B1FB80BF) Sender: linux-wireless-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On Thu, 2017-01-26 at 06:45 -0800, Eric Dumazet wrote: > On Thu, 2017-01-26 at 14:49 +0100, Johannes Berg wrote: > > > Oops, sorry - receive. We can only indicate "CHECKSUM_UNNECESSARY", > > nothing more advanced right now, but right now we'd indicate that > > if > > the packet had 0x0000 in the checksum field, but should've had > > 0xffff. > > > > On TX I believe we actually do in HW exactly what your patch just > > did. > > Can you describe the visible effects of this problem ? > > Is that because of a conversion we might do later to > CHECKSUM_COMPLETE ? Unfortunately, I haven't been able to actually test this yet. I also didn't find the code that would drop frames with CSUM 0 either, so I'm thinking - for now - that if all the csum handling is skipped, dropping 0 csum frames would also be, and then we'd accept a frame we should actually have dropped. I'll go test this I guess :) Any pointers to where 0 csum frames are dropped? johannes