Files
firezone/rust/relay
Jamil 573124bd2f Document relay gateway client CLIs (#2424)
Fixes #2363 

* Rename `relay` package to `firezone-relay` so that binaries outputted
match the `firezone-*` cli naming scheme
* Rename `firezone-headless-client` package to `firezone-linux-client`
for consistency
* Add READMEs for user-facing CLI components (there will also be docs
later)
2023-10-19 00:59:17 +00:00
..

relay

This crate houses a minimalistic STUN & TURN server.

Features

We aim to support the following feature set:

  • STUN binding requests
  • TURN allocate requests
  • TURN refresh requests
  • TURN channel bind requests
  • TURN channel data requests

Relaying of data through other means such as DATA frames is not supported.

Building

You can build the relay using: cargo build --release --bin firezone-relay

You should then find a binary in target/release/firezone-relay.

Running

To run the relay:

firezone-relay --portal_token <portal_token>

where portal_token is the token shown when creating a Relay in the Firezone admin portal.

For an up-to-date documentation on the available configurations options and a detailed help text, run cargo run --bin relay -- --help. All command-line options can be overridden using environment variables. Those variables are listed in the --help output at the bottom of each command.

Ports

The relay listens on port 3478. This is the standard port for STUN/TURN and not configurable. Additionally, the relay needs to have access to the port range 49152 - 65535 for the allocations.

Portal Connection

When given a portal_token, the relay will connect to the Firezone portal (default wss://api.firezone.dev) and wait for an init message before commencing relay operations.

Design

The relay is designed in a sans-IO fashion, meaning the core components do not cause side effects but operate as pure, synchronous state machines. They take in data and emit commands: wake me at this point in time, send these bytes to this peer, etc.

This allows us to very easily unit-test all kinds of scenarios because all inputs are simple values.

The main server runs in a single task and spawns one additional task for each allocation. Incoming data that needs to be relayed is forwarded to the main task where it gets authenticated and relayed on success.