Design stuff

[kevinboulain]

From the README.md, it looks like you want to rework the thread & socket management. The Python community seems to have shifted to the asynchronous IO paradigm. It could probably give cleaner code & better performance.
For a small project build from scratch that doesn't need to leverage other libraries I would recommend curio (much easier to grasp and has less pitfalls than asyncio or there is trio which I never used but is inspired by curio's design principles).
I'll let you look at the examples to see how much the a client/server implementation may be cleaner.

Also, it seems you require root permissions so why don't you bring up a real tunnel and handle more than TCP by creating TUN or TAP devices (by opening /dev/net/tun on Linux)? It's easy to do with Python, if a bit obscur (since you'll have to define a couple of things yourself instead of relying on header files). The downside being you'll probably need to assign IP addresses on both sides.

[kevinboulain]

Closing, not a real issue.