When trying to enable this functionality upstream, I see it does not unSNAT the packet, and a needs frag packet is sent out the physical interface of the host with the join subnet IP of the gateway router:

https://github.com/ovn-org/ovn-kubernetes/pull/4025#issuecomment-1828641987

It failed every control-plane job. The OVN and OVS DBs can be found by downloading any of the kind-logs zip files. For example: 

https://github.com/ovn-org/ovn-kubernetes/suites/18535596409/artifacts/1076212679

unzip the file and go to folder e2e-dbs which will have the OVS and OVN dbs for each node (this is an HA run (no interconnect) so there are multiple OVN DBs. The test log is here:

https://github.com/ovn-org/ovn-kubernetes/actions/runs/7009478266/job/19068818098?pr=4025

You can also deploy kind in ovn-kubernetes from my PR (./kind.sh -wk 2), then go to the test folder:

export OVN_HA=false
export KIND_IPV6_SUPPORT=false
export KIND_IPV4_SUPPORT=true
make control-plane WHAT=".*queries to the hostNetworked server pod on another node shall work for UDP.*"