Unfortunately not at the moment, as all is kinda fiddled and setup manually, but I’m redoing my home lab in a couple of weeks. Send me a message and I’ll send you the docker image or script!
But basically I did the following:
enable ipv4 forwarding
configure and start VPN tunnel
set the default route to the tunnel
set the gw for reaching the remote vpn server to the local gw
sets routes for the local network to the local gw
If your vpn goes down, the default route shall still point to the remote gw, but as it isn’t there you also have a kill switch. Voila!
I am looking into gluetun but haven’t tried it yet.
Edit: this doesn’t protect you from someone snooping the traffic inside your local net, but protects it starting from the point where it leaves the local vpngw. The traffic is unencrypted between that and your client.