diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md new file mode 120000 index 000000000..8378fd7d8 --- /dev/null +++ b/.github/copilot-instructions.md @@ -0,0 +1 @@ +docs/AGENT.md \ No newline at end of file diff --git a/docs/AGENT.md b/docs/AGENT.md new file mode 100644 index 000000000..ce6faa758 --- /dev/null +++ b/docs/AGENT.md @@ -0,0 +1,33 @@ +# AI agent rules for Firezone + +## Summary + +Firezone is a zero-trust access platform built on top of WireGuard. +The data plane components are built in Rust and reside in `rust/`. +The control plane components are built in Elixir and reside in `elixir/`. + +## Data plane architecture + +At the core of the data plane resides a shared library called [`connlib`](../rust/connlib). +It combines ICE (using the `str0m` library) and WireGuard (using the `boringtun` library) to establish on-the-fly tunnels between Clients and Gateways. +The entry-point for the data plane is [`Tunnel`](../rust/connlib/tunnel) which acts as a big event-loop combining three components: + +- A platform-specific TUN device +- A sans-IO state component representing either the Client or the Gateway +- A platform-specific UDP socket + +Packets from IO sources (TUN device and UDP socket) are passed to the state component, resulting in a UDP or IP packet. +The state component also manages ICE through the [`snownet`](../rust/connlib/snownet) library, so some UDP traffic is handled internally and does not yield an IP packet. + +These three components are split into multiple threads and connected via bounded channels: + +- 1 thread for reading from the TUN device +- 1 thread for writing to the TUN device +- 1 thread for handling IPv4 UDP traffic with 1 task each for sending / receiving +- 1 thread for handling IPv6 UDP traffic with 1 task each for sending / receiving +- 1 task on the "main" thread that holds the state and reads / writes from and to the channels connecting to the IO threads + +## Code review guidelines + +- Assume that code compiles and is syntactically correct. +- Focus on consistency and correctness.