I made a post about the DNS tunnel I have been working on. It uses a DNS over HTTPS or DNS over TLS resolver for covertness, and the interior of the tunnel follows the Turbo Tunnel design so the peers can be more free about when they send to each other.
https://github.com/net4people/bbs/issues/30
It doesn't exist as a proper pluggable transport, but it's pretty easy to hack together a way to access a bridge through the tunnel. I made the linked post using Tor Browser through the DNS tunnel. It's just two steps.
First, get the tunnel client software and run it with the proper parameters. git clone https://www.bamsoftware.com/git/dnstt.git cd dnstt-client go build ./dnstt-client -doh https://dns.google/dns-query -pubkey a8090ab2d7b918e69ed4b2340fcd9c2af33c08e3620af98fb9c6a460fb63f76d tor.rinsed-tinsel.site 127.0.0.1:7000 You can replace "https://dns.google/dns-query" with another server from https://github.com/curl/curl/wiki/DNS-over-HTTPS#publicly-available-servers
Second, in Tor Browser, go to about:preferences#tor, select "Provide a bridge", and enter 127.0.0.1:7000 4D6C0DF6DEC9398A4DEF07084F3CD395A96DD2AD tor will connect to 127.0.0.1:7000 as if it were a remote bridge, but that port actually leads through the tunnel to the ORPort of my bridge giygas.
What I had to do to set up the server side: first I went into the DNS configuration for my domain rinsed-tinsel.site and added the records A tns.rinsed-tinsel.site points to 192.81.135.242 AAAA tns.rinsed-tinsel.site points to 2600:3c01::f03c:91ff:fe73:b602 NS tor.rinsed-tinsel.site is managed by tns.rinsed-tinsel.site The A and AAAA records are the IP addresses of my bridge. Then I ran the following server commands (plus port forwarding for port 53). Notice that the tunnel server is configured to terminate the tunnel at the ORPort of the locally running tor bridge. ./dnstt-server -gen-key -privkey-file dnstt-tor.key -pubkey-file dnstt-tor.pub ./dnstt-server -udp :5300 -privkey-file dnstt-tor.key tor.rinsed-tinsel.site 192.81.135.242:9001
I won't commit to running the server part of the tunnel forever, but I'll leave it set up the way it is for a while in case you want to try it.