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Upon receiving a SIGTERM, we immediately disconnect from the websocket connection to the portal and set a flag that we are shutting down. Once we are disconnected from the portal and no longer have an active allocations, we exit with 0. A repeated SIGTERM signal will interrupt this process and force the relay to shutdown. Disconnecting from the portal will (eventually) trigger a message to clients and gateways that this relay should no longer be used. Thus, depending on the timeout our supervisor has configured after sending SIGTERM, the relay will continue all TURN operations until the number of allocations drops to 0. Currently, we also allow clients to make new allocations and refreshing existing allocations. In the future, it may make sense to implement a dedicated status code and refuse `ALLOCATE` and `REFRESH` messages whilst we are shutting down. Related: #4548. --------- Signed-off-by: Thomas Eizinger <thomas@eizinger.io> Co-authored-by: Jamil <jamilbk@users.noreply.github.com>
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
The Firezone Relay supports Linux only. To run the Relay binary on your Linux host:
- Generate a new Relay token from the "Relays" section of the admin portal and save it in your secrets manager.
- Ensure the
FIREZONE_TOKEN=<relay_token>environment variable is set securely in your Relay's shell environment. The Relay expects this variable at startup. - Now, you can start the Firezone Relay with:
firezone-relay
To view more advanced configuration options pass the --help flag:
firezone-relay --help
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 token, the relay will connect to the Firezone portal 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.