Re: [PATCH net-next v7 1/2] Add nolocalbypass option to vxlan.

[Stephen Hemminger <stephen@networkplumber.org>]

On Tue,  2 May 2023 00:25:29 +0800
Vladimir Nikishkin <vladimir@nikishkin.pw> wrote:

> If a packet needs to be encapsulated towards a local destination IP and
> a VXLAN device that matches the destination port and VNI exists, then
> the packet will be injected into the Rx path as if it was received by
> the target VXLAN device without undergoing encapsulation. If such a
> device does not exist, the packet will be dropped.
> 
> There are scenarios where we do not want to drop such packets and
> instead want to let them be encapsulated and locally received by a user
> space program that post-processes these VXLAN packets.
> 
> To that end, add a new VXLAN device attribute that controls whether such
> packets are dropped or not. When set ("localbypass") these packets are
> dropped and when unset ("nolocalbypass") the packets are encapsulated
> and locally delivered to the listening user space application. Default
> to "localbypass" to maintain existing behavior.
> 
> Signed-off-by: Vladimir Nikishkin <vladimir@nikishkin.pw>

Is there some way to use BPF for this. Rather than a special case
for some userspace program?