UDP Proxy mirror host to container

To monitor UDP data going over a network bridge made with unix bridge_utils I want to mirror or reflect data received by a host network interface to a container using a proxy device.

I’ve succesfully done this using tc, but would like to use a purely lxd based solution.

In my first attempt to add a proxy for the udp protocol, it doesn’t seem to be forwarding the UDP traffic.

$ lxc config device add ub proxy0 proxy listen=udp: connect=udp:

I’m not sure why this isn’t forwarding the traffic, and how to reflect instead of forward.
With reflect I mean the tc filter action mirred, as described in the second half of this tutorial

I’m hoping someone here can help me!