Re: [PATCH net-next 00/10] udp: implement GRO support

[David Miller <davem@davemloft.net>]

From: Paolo Abeni <pabeni@redhat.com>
Date: Wed,  7 Nov 2018 12:38:27 +0100

> This series implements GRO support for UDP sockets, as the RX counterpart
> of commit bec1f6f69736 ("udp: generate gso with UDP_SEGMENT").
> The core functionality is implemented by the second patch, introducing a new
> sockopt to enable UDP_GRO, while patch 3 implements support for passing the
> segment size to the user space via a new cmsg.
> UDP GRO performs a socket lookup for each ingress packets and aggregate datagram
> directed to UDP GRO enabled sockets with constant l4 tuple.
> 
> UDP GRO packets can land on non GRO-enabled sockets, e.g. due to iptables NAT
> rules, and that could potentially confuse existing applications.
> 
> The solution adopted here is to de-segment the GRO packet before enqueuing
> as needed. Since we must cope with packet reinsertion after de-segmentation,
> the relevant code is factored-out in ipv4 and ipv6 specific helpers and exposed
> to UDP usage.
> 
> While the current code can probably be improved, this safeguard ,implemented in
> the patches 4-7, allows future enachements to enable UDP GSO offload on more
> virtual devices eventually even on forwarded packets.
> 
> The last 4 for patches implement some performance and functional self-tests,
> re-using the existing udpgso infrastructure. The problematic scenario described
> above is explicitly tested.
> 
> This revision of the series try to address the feedback provided by Willem and
> Subash on previous iteration.

Series applied.