On Mon, 2021-03-29 at 08:31 -0400, Willem de Bruijn wrote:
On Mon, Mar 29, 2021 at 4:14 AM Paolo Abeni [off-list ref] wrote:
quoted
On Fri, 2021-03-26 at 14:15 -0400, Willem de Bruijn wrote:
quoted
On Thu, Mar 25, 2021 at 1:24 PM Paolo Abeni [off-list ref] wrote:
quoted
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 <pabeni@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?
In this series, yes.
quoted
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;
This is not ovious at all to me.
quoted
+ /* 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.
Overall looks more complex to me. I would keep the extra bit, unless
you have strong opinion.
Sounds good.
quoted
Side note: I was wondering about a follow-up to simplify the condition:
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) {
Since UDP sockets could process (segmenting as needed) unexpected GSO
packets, we could always do 'NETIF_F_GRO_UDP_FWD', when enabled on the
device level. The above becomes:
if (skb->dev->features & NETIF_F_GRO_UDP_FWD) ||
(sk && udp_sk(sk)->gro_enabled && !up->encap_rcv) ||
NAPI_GRO_CB(skb)->is_flist) {
which is hopefully more clear (and simpler). As said, non for this
series anyhow.
UDP sockets can segment, but it is expensive. In this case I think the
simplification is not worth the possible regression.
No strong opinion here, I will not do the thing mentioned above.
Thanks!
Paolo