tun2proxy/README.md

# tun2proxy
Tunnel TCP traffic through SOCKS5 or HTTP on Linux.

**Authentication not yet supported. Error handling incomplete and too restrictive.**

## Build
Clone the repository and `cd` into the project folder. Then run the following:
```
cargo build --release
```

## Setup
A standard setup, which would route all traffic from your system through the tunnel interface, could look as follows:
```shell
# Define the proxy endpoint.
PROXY_IP=1.2.3.4
PROXY_PORT=1080

# Create a tunnel interface named tun0 which your user can bind to, so we don't need to run tun2proxy as root.
sudo ip tuntap add name tun0 mode tun user $USER
sudo ip link set tun0 up

# To prevent a routing loop, we add a route to the proxy server that behaves like the default route.
sudo ip route add "$PROXY_IP" $(ip route | grep '^default' | cut -d ' ' -f 2-)

# Route all your traffic through tun0 without interfering with the default route.
sudo ip route add 128.0.0.0/1 dev tun0
sudo ip route add 0.0.0.0/1 dev tun0

./target/release/tun2proxy --tun tun0 --socks5 "$PROXY_IP:$PROXY_PORT"
```

Note that if you paste these commands into a shell script, which you then run with `sudo`, you might want to replace
`$USER` with `$SUDO_USER`.

For DNS to work, you might need an additional tool like [dnsproxy](https://github.com/AdguardTeam/dnsproxy) that is
configured to listen on a local UDP port and communicates with the upstream DNS server via TCP.

## CLI
```
Tunnel interface to proxy.

Usage: tun2proxy --tun <TUN> --proxy <PROXY_TYPE> --addr <ADDR>

Options:
  -t, --tun <TUN>           Name of the tun interface
  -p, --proxy <PROXY_TYPE>  What proxy type to run [possible values: socks5, http]
  -a, --addr <ADDR>         Server address with format IP:PORT
  -h, --help                Print help (see more with '--help')
  -V, --version             Print version
```

## TODO
- Authentication for SOCKS (plain) and HTTP (base64)
- UDP support for SOCKS
- Virtual DNS