mitmproxy_wireguard

Transparently proxy any device that can be configured as a WireGuard client!

DONE

• multithreaded / asynchronous WireGuard server using tokio:
  • one worker thread for the user-space WireGuard server
  • one worker thread for the user-space network stack
  • one worker thread for communicating with the Python runtime
• full support for IPv4 packets (TCP and UDP)
• partial support for IPv6 packets (TCP and UDP)
• Python interface similar to the Python asyncio module
• integration tests in mitmproxy

TODO

• more complete IPv6 support
• various other small TODO and FIXME items

Architecture support

mitmproxy_wireguard should work on most architectures / targets - including, but not limited to Windows, macOS, and Linux, running on x86_64 (x64) and aarch64 (arm64) CPUs.

Binary wheels for the following targets are available from PyPI:

• Windows / x64 (x86_64-windows-msvc)
• macOS / Intel (x86_64-apple-darwin)
• macos / Apple Silicon (aarch64-apple-darwin) via "Universal 2" binaries
• Linux / x86_64 (x86_64-unknown-linux-gnu)
• Linux / aarch64 (aarch64-unknown-linux-gnu), i.e. for Raspberry Pi 2+ and similar devices

Requirements

mitmproxy_wireguard currently requires Python 3.7 or newer at runtime, since that is the oldest version of Python that is still supported by PyO3 v0.16. mitmproxy already requires Python 3.9 or newer, so this should not be a problem.

Additionally, mitmproxy_wireguard currently has the following requirements at build-time:

• Python 3.7+ (range of Python versions that is supported by PyO3 v0.16)
• Rust 1.58.0+ (the oldest supported version of Rust / MSRV is 1.58.0)
• maturin 0.13.x

Architecture

Interface

The API interface of the PyO3 module is documented in mitmproxy_wireguard.pyi:

• Server class: a running WireGuard server instance, with methods for
  • graceful shutdown (close / wait_closed)
  • sending UDP packets
• TcpStream class: an established TCP connection (provides APIs identical to Python's) asyncio.StreamReader and asyncio.StreamWriter)
• start_server coroutine: initialize, start, and return a Server instance

Hacking

Setting up the development environment is relatively straightforward, as only a Rust toolchain and Python 3 are required:

# set up a new venv
python3 -m venv venv

# enter venv (use the activation script for your shell)
source ./venv/bin/activate

# install maturin and pdoc
pip install maturin pdoc

Compiling the native Rust module then becomes easy:

# compile native Rust module and install it in venv
maturin develop

# compile native Rust module with optimizations
maturin develop --release

Once that's done (phew! Rust sure does take a while to compile!), the test echo server should work correctly. It will print instructions for connecting to it over a WireGuard VPN:

python3 ./echo_test_server.py

The included mitm-wg-test-client binary can be used to test this echo test server, which can be built by running cargo build inside the test-client directory, and launched from target/debug/mitm-wg-test-client.

Docs

Documentation for the Python module can be built with pdoc.

The documentation is built from the mitmproxy_wireguard.pyi type stubs and the rustdoc documentation strings themselves. So to generate the documentation, the native module needs to be rebuilt, as well:

maturin develop
pdoc mitmproxy_wireguard

By default, this will build the documentation in HTML format and serve it on http://localhost:8080.

Note: This requires version >=11.2.0 of pdoc. It is the first version that supports generating documentation for "native-only" Python modules (like our mitmproxy_wireguard PyO3 module).

Introspecting the tokio runtime

The asynchronous runtime can be introspected using tokio-console if the crate was built with the tracing feature:

tokio-console http://localhost:6669

There should be no task that is busy when the program is idle, i.e. there should be no busy waiting.

Note: This requires maturin>=0.12.15, as earlier versions accidentally clobbered the RUSTFLAGS that were passed to the Rust compiler, breaking use of the console_subscriber for tokio-console, which requires using the --cfg tokio_unstable flag.

Code style

The format for Rust code is enforced by rustfmt. To apply the formatting rules, use:

cargo fmt

The format for Python code (i.e. the test echo server and the type stubs in mitmproxy_wireguard.pyi) is enforced with black and can be applied with:

black echo_test_server.py mitmproxy_wireguard.pyi benches/*.py