# relay_server

Rust QUIC implementation of the RelayKit TCP relay server.

Each QUIC connection replaces the old UDP peer. Each QUIC bidirectional stream
replaces the old `stream_id` and maps to one outbound TCP connection. QUIC
provides ordered stream delivery and connection encryption, so the old UDP frame
header encryption is intentionally not present.

## Run

```sh
cargo run -- config.toml
```

The server also reads the config path from `RELAY_SERVER_CONFIG`. If neither is
provided and `config.toml` does not exist, built-in defaults are used.

## Stream Protocol

The client opens a QUIC bidirectional stream and writes one open request using
the old binary payload format:

```text
host_len(2), host(host_len), port(2),
username_len(2), username(username_len),
password_len(2), password(password_len)
```

All integers are unsigned big-endian values. After authentication and a
successful TCP connect, the server writes:

```text
0
```

Then both sides relay raw TCP bytes over the QUIC stream. On failure, the server
writes:

```text
1, error_len(2), error(error_len)
```