Re: [PATCH v4 net-next 2/2] udp: allow forwarding of plain (non-fraglisted) UDP GRO packets

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

On Fri, Jan 22, 2021 at 1:20 PM Alexander Lobakin <alobakin@pm.me> wrote:
>
> Commit 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.") actually
> not only added a support for fraglisted UDP GRO, but also tweaked
> some logics the way that non-fraglisted UDP GRO started to work for
> forwarding too.
> Commit 2e4ef10f5850 ("net: add GSO UDP L4 and GSO fraglists to the
> list of software-backed types") added GSO UDP L4 to the list of
> software GSO to allow virtual netdevs to forward them as is up to
> the real drivers.
>
> Tests showed that currently forwarding and NATing of plain UDP GRO
> packets are performed fully correctly, regardless if the target
> netdevice has a support for hardware/driver GSO UDP L4 or not.
> Add the last element and allow to form plain UDP GRO packets if
> we are on forwarding path, and the new NETIF_F_GRO_UDP_FWD is
> enabled on a receiving netdevice.
>
> If both NETIF_F_GRO_FRAGLIST and NETIF_F_GRO_UDP_FWD are set,
> fraglisted GRO takes precedence. This keeps the current behaviour
> and is generally more optimal for now, as the number of NICs with
> hardware USO offload is relatively small.
>
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>

Acked-by: Willem de Bruijn <willemb@google.com>