# rustunnel CLI

The rustunnel binary exposes five subcommands defined in `src/cli.rs` and dispatched in `src/main.rs`.

## Commands

### `listen`

Start the HTTPS tunnel listener. Binds an HTTPS server that accepts mTLS connections from connectors.

Key arguments:
- `--listen` — bind address (default `0.0.0.0:4180`)
- `--advertise` — public host added to the derived server cert and used in the printed connect hint
- `--connection-key` — reusable key generated by `keygen` or a previous `listen` run
- `--socks` — optional server-side SOCKS5 proxy address for connector-side network access
- `--cert`, `--key`, `--ca-cert` — TLS material paths (required unless using a connection key)
- `--auth-token`, `--auth-token-file` — application auth token
- `--insecure-skip-tls-verify` — skip client certificate verification (lab only)

When run without explicit certificate paths and without a connection key, `listen` auto-generates a new connection key and prints it.

### `connect`

Connect to the listener and expose a local SOCKS5 proxy.

Key arguments:
- `CONNECTION_KEY` — positional connection key (optional)
- `--target` — listener address (required; not stored in the key)
- `--connection-key` — connection key via flag or env `RUSTUNNEL_KEY`
- `--socks` — local SOCKS5 proxy address (default `127.0.0.1:1180`)
- `--cert`, `--key`, `--ca-cert` — TLS material paths (required unless using a connection key)
- `--insecure-skip-tls-verify` — skip server certificate verification (lab only)

### `generate`

Generate local certificate and auth material into an output directory.

Creates: `ca.pem`, `ca.key`, `server.crt`, `server.key`, `client.crt`, `client.key`, `token.txt`, `config.json`.

### `keygen`

Print a fresh ~49-char connection key (prefix `rtun3.`). The key is a random 32-byte
seed from which both endpoints derive identical TLS material; no certificates are
shipped. Pass the target address separately on `connect`.

### `version`

Print version, edition, platform, and architecture.

## Entry point

`src/main.rs` installs the ring crypto provider, initializes tracing with an env-filter defaulting to `info`, parses the CLI, and dispatches to the appropriate runner function.

## Key source files

| File | Purpose |
| ---- | ------- |
| `src/cli.rs` | clap `Parser` and `Subcommand` definitions |
| `src/main.rs` | Entry point, command dispatch, host:port parsing helpers |