tunsocks[0] might be of interest to you. It's very similar to the software mentioned by OP except in C. It uses the lwIP usermode tcp/ip stack. It doesn't itsel

tunsocks[0] might be of interest to you. It's very similar to the software mentioned by OP except in C. It uses the lwIP usermode tcp/ip stack. It doesn't itself have any VPN or tunneling support, but instead relies on raw packets being passed into and out of a pipe. It can then provide access to that network via various proxies, port forwards, and even raw packets via NAT (very useful for VMs). [0]: https://github.com/russdill/tunsocks https://github.com/russdill/tunsocks