On Sat, May 5, 2018 at 3:31 AM, Alexander Duyck
<alexander.du...@gmail.com> wrote:
> From: Alexander Duyck <alexander.h.du...@intel.com>
>
> This patch adds support for a software provided checksum and GSO_PARTIAL
> segmentation support. With this we can offload UDP segmentation on devices
> that only have partial support for tunnels.
>
> Since we are no longer needing the hardware checksum we can drop the checks
> in the segmentation code that were verifying if it was present.
>
> Signed-off-by: Alexander Duyck <alexander.h.du...@intel.com>
> ---
> net/ipv4/udp_offload.c | 28 ++++++++++++++++++----------
> net/ipv6/udp_offload.c | 11 +----------
> 2 files changed, 19 insertions(+), 20 deletions(-)
>
> diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
> index 946d06d2aa0c..fd94bbb369b2 100644
> --- a/net/ipv4/udp_offload.c
> +++ b/net/ipv4/udp_offload.c
> @@ -217,6 +217,13 @@ struct sk_buff *__udp_gso_segment(struct sk_buff
> *gso_skb,
> return segs;
> }
>
> + /* GSO partial and frag_list segmentation only requires splitting
> + * the frame into an MSS multiple and possibly a remainder, both
> + * cases return a GSO skb. So update the mss now.
> + */
> + if (skb_is_gso(segs))
> + mss *= skb_shinfo(segs)->gso_segs;
> +
> seg = segs;
> uh = udp_hdr(seg);
>
> @@ -237,6 +244,11 @@ struct sk_buff *__udp_gso_segment(struct sk_buff
> *gso_skb,
> uh->len = newlen;
> uh->check = check;
>
> + if (seg->ip_summed == CHECKSUM_PARTIAL)
> + gso_reset_checksum(seg, ~check);
> + else
> + uh->check = gso_make_checksum(seg, ~check);
Here and below, this needs
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;
similar to __skb_udp_tunnel_segment?
