rtptun

rtptun is a UDP tunnel that reshapes UDP traffic as RTP, helping you get VPN traffic through protocol whitelists.

Features

• Lightweight
• Asynchronous
• Cross-platform (tested on Linux, Windows and Android)
• Payload encryption (ChaCha20-Poly1305)

Limitations

• No forward secrecy
• No replay protection

Requirements

• GCC (GCC 8 or higher recommended)
• Make
• Cygwin (for Windows builds)
• libsodium
• libev

Building

Installing required dependencies

Ubuntu/Debian

# apt install libev-dev libsodium-dev

Termux

$ pkg install libev libsodium

Alpine

# apk add libev-dev libsodium-dev
# apk add libsodium-static # (optional, needed for static builds)

Cygwin

• gcc-core
• make
• libev-devel
• libsodium-devel

Compiling

There are several build types available:

Release build

Produces optimized binary.

Recommended. This is usually what you want to go with.

$ make -j$(nproc) DEBUG=0 STATIC=0

Static release build

Same as release build but produces a static binary.

Static builds do not work under Windows yet.

$ make -j$(nproc) DEBUG=0 STATIC=1

Debug build

Produces unopimized binary with debug information.

Should only be used for development purposes.

$ make -j$(nproc) DEBUG=1 STATIC=0

Installation

Release build

$ make install DEBUG=0 STATIC=0

Static release build

$ make install DEBUG=0 STATIC=1

Usage

Usage: rtptun <action> <options>
Example:
 - Generate key:     rtptun genkey
 - Run server:       rtptun server -k <KEY> -l 5004 -p 1194
 - Run client:       rtptun client -k <KEY> -l 1194 -d 192.0.2.1 -p 5004
 - Load config file: rtptun -f /etc/rtptun.conf

Actions:
  client  : run as client
  server  : run as server
  genkey  : generate encryption key

Server options:
  -i : listen address (default: 0.0.0.0)
  -l : listen port (default: 5004)
  -d : destination address (default: 127.0.0.1)
  -p : destination port
  -k : encryption key

Client options:
  -i : local address (default: 127.0.0.1)
  -l : local port
  -d : server address
  -p : server port (default: 5004)
  -k : encryption key

Program options:
  -f : Load configuration file
  -h : display help message
  -v : verbose
  -V : display version information

Example

Generating a key

Both client and server must use the same key. You can generate a new random key using:

$ rtptun genkey

Server

Assuming there's a VPN server (OpenVPN/WireGuard/...) running on port 1194:

$ rtptun server -k <KEY> -l 5004 -p 1194

rtptun server will be listening on port 5004 for rtptun clients to connect and tunnel their traffic to the VPN server running on port 1194.

Client

$ rtptun client -k <KEY> -l 1194 -d 192.0.2.1 -p 5004

rtptun will listen locally on port 1194 and tunnel traffic to rtptun server running on host 192.0.2.1 and port 5004.

Disclaimer

Here be dragons!

I'm no security expert, I've written this software just to learn a thing or two about networking. I'm not responsible if Lum-chan invades your home and steals your cookies.

Use this software at your own discretion.

External Libraries

• libsodium - ISC
• libev - BSD-2-Clause
• uthash - BSD revised
• Cygwin (for Windows builds) - LGPLv3