[ovs-dev] [PATCH v7] datapath: Add support for lwtunnel

[Joe Stringer]

On 1 December 2015 at 19:04, Pravin B Shelar <pshelar at nicira.com> wrote:

> Following patch adds support for lwtunnel to OVS datapath.
> With this change OVS datapath detect lwtunnel support and
> make use of new APIs if available. On older kernel where the
> support is not there the backported tunnel modules are used.
> These backported tunnel devices acts as lwtunnel devices.
> I tried to keep backported module same as upstream for easier
> bug-fix backport. Since STT and LISP are not upstream OVS
> always needs to use respective modules from tunnel compat layer.
> To make it work on kernel 4.3 I have converted STT and LISP
> modules to lwtunnel API model.
>
> lwtunnel make use of skb-dst to pass tunnel information to the
> tunnel module. On older kernel this is not possible. So the in
> case of old kernel metadata ref is stored in OVS_CB and direct
> call to tunnel transmit function is made by respective tunnel
> vport modules. Similarly on receive side tunnel recv directly
> call netdev-vport-receive to pass the skb to OVS.
>
> Major backported components include:
> Geneve, GRE, VXLAN, ip_tunnel, udp-tunnels GRO.
>
> Signed-off-by: Pravin B Shelar <pshelar at nicira.com>
>

My testing of this seems pretty positive - haven't hit any particular
issues (although I've only tested fairly lightly with vxlan tunnels).
Travis reports a minor warning with STT on newer (4.1,4.2) kernels, and
what looks like a trivial warning on 3.10 (also stt). I don't consider
these particularly strong reasons to block merging for now. This will get
further testing during the branch-2.5 testing phase.

Acked-by: Joe Stringer <joe at ovn.org>