On Thu, 2017-01-26 at 07:24 -0800, Eric Dumazet wrote:

On Thu, 2017-01-26 at 15:49 +0100, Johannes Berg wrote:

quoted

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?

Probably in udp6_csum_init()

vi +804 net/ipv6/udp.c

                if (!uh->check && !udp_sk(sk)->no_check6_rx) {
                        udp6_csum_zero_error(skb);
                        goto csum_error;
                }