On Thu, Mar 25, 2021 at 1:24 PM Paolo Abeni <pab...@redhat.com> wrote:
>
> Currently the UDP protocol delivers GSO_FRAGLIST packets to
> the sockets without the expected segmentation.
>
> This change addresses the issue introducing and maintaining
> a couple of new fields to explicitly accept SKB_GSO_UDP_L4
> or GSO_FRAGLIST packets. Additionally updates udp_unexpected_gso()
> accordingly.
>
> UDP sockets enabling UDP_GRO stil keep accept_udp_fraglist
> zeroed.
>
> v1 -> v2:
> - use 2 bits instead of a whole GSO bitmask (Willem)
>
> Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.")
> Signed-off-by: Paolo Abeni <pab...@redhat.com>
This looks good to me in principle, thanks for the revision.
I hadn't fully appreciated that gro_enabled implies accept_udp_l4, but
not necessarily vice versa.
It is equivalent to (accept_udp_l4 && !up->gro_receive), right?
Could the extra bit be avoided with
"
+ /* Prefer fraglist GRO unless target is a socket with UDP_GRO,
+ * which requires all but last segments to be of same gso_size,
passed in cmsg */
if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
- NAPI_GRO_CB(skb)->is_flist = sk ? !udp_sk(sk)->gro_enabled: 1;
+ NAPI_GRO_CB(skb)->is_flist = sk ?
(!udp_sk(sk)->gro_enabled || udp_sk(sk)->accept_udp_fraglist) : 1;
+ /* Apply transport layer GRO if forwarding is enabled or the
flow lands at a local socket */
if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
(sk && udp_sk(sk)->gro_enabled && !up->encap_rcv) ||
NAPI_GRO_CB(skb)->is_flist) {
pp = call_gro_receive(udp_gro_receive_segment, head, skb);
return pp;
}
+ /* Continue with tunnel GRO */
"
.. not that the extra bit matters a lot. And these two conditions with
gro_enabled are not very obvious.
Just a thought.
