On 5/23/25 8:09 AM, Paolo Abeni wrote:

On 5/23/25 12:29 AM, Willem de Bruijn wrote:

quoted

Paolo Abeni wrote:

quoted

+	/* No UDP fragments over UDP tunnel. */

What are udp fragments and why is TCP with ECN not supported?

"udp fragments" is the syncopated form of "UDP datagrams carryed by IP
fragments". I'll use UFO to be clearer ;)

The ECN part is cargo cult on my side from my original implementation
which dates back to ... a lot of time ago. A quick recheck makes me
think I could drop it. I'll have a better look and either document the
choice or drop the check in the next revision.

Let me quote the relevant code:

quoted

quoted

+	gso_inner_type = hdr->gso_type & ~(VIRTIO_NET_HDR_GSO_ECN |
+					   gso_tunnel_type);
+	if (!gso_inner_type || gso_inner_type == VIRTIO_NET_HDR_GSO_UDP)
+		return -EINVAL;

Actually GSO_ECN is allowed. What is _not_ allowed is the GSO_ECN
offload without a paired plain GSO. The intention here is to ensure that
the GSO over UDP tunnel packets actually includes/requires an inner GSO
offload. I'll update the comment accordingly.

Thanks,

Paolo