Re: [PATCH net v2] udp: Compute L4 checksum as usual when not segmenting the skb

Jakub Sitnicki wrote:

If:

1. the user requested USO, but
2. there is not enough payload for GSO to kick in, and
3. the egress device doesn't offer checksum offload, then

we want to compute the L4 checksum in software early on.

In the case when we are not taking the GSO path, but it has been requested, the software checksum fallback in skb_segment doesn't get a chance to compute the full checksum, if the egress device can't do it. As a result we end up sending UDP datagrams with only a partial checksum filled in, which the peer will discard.

Fixes: 10154dbded6d ("udp: Allow GSO transmit from devices with no checksum offload") Reported-by: Ivan Babrou ivan@cloudflare.com Signed-off-by: Jakub Sitnicki jakub@cloudflare.com Acked-by: Willem de Bruijn willemdebruijn.kernel@gmail.com Cc: stable@vger.kernel.org

You already included my Acked-by, but just to confirm: LGTM.