# LAN Share

A peer-to-peer screen sharing application for local networks. No accounts, no cloud services — just open a browser and share.

## Features

- **WebRTC P2P**: Direct peer-to-peer connections, video never touches the server
- **Audio support**: Optionally share system audio with your screen
- **Multiple streams**: View multiple shared screens, select which one to focus on
- **Zero config**: Just run the server and open the URL in any browser
- **Keyboard shortcuts**: `F` for fullscreen, `M` for mute, `Escape` to expand sidebar

## Building

```bash
cargo build --release
```

The binary will be at `target/release/lanshare`.

## Running

```bash
./target/release/lanshare
```

Or with cargo:

```bash
cargo run --release
```

The server starts on `http://0.0.0.0:8080` by default.

### CLI Options

```
Usage: lanshare [OPTIONS]

Options:
  -H, --host <IP>    IP address to bind to [default: 0.0.0.0]
  -p, --port <PORT>  Port to listen on [default: 8080]
  -v, --verbose      Enable verbose/debug logging
  -q, --quiet        Quiet mode - only show errors
  -h, --help         Print help
  -V, --version      Print version
```

Examples:

```bash
# Listen on a specific interface
lanshare --host 192.168.1.100 --port 3000

# Localhost only (for testing)
lanshare -H 127.0.0.1

# Quiet mode
lanshare -q
```

### CLI Options

```
LAN Share - Peer-to-peer screen sharing for local networks

Usage: lanshare [OPTIONS]

Options:
  -H, --host <HOST>  Host address to bind to [default: 0.0.0.0]
  -p, --port <PORT>  Port to listen on [default: 8080]
  -v, --verbose      Enable verbose logging
  -h, --help         Print help
  -V, --version      Print version
```

### Examples

```bash
# Run on default settings (0.0.0.0:8080)
lanshare

# Run on a specific port
lanshare -p 3000

# Bind to localhost only
lanshare -H 127.0.0.1 -p 8080

# Run with verbose logging
lanshare -v
```

## Usage

1. Start the server on any machine in your LAN
2. Open `http://<server-ip>:8080` in a browser on each device
3. Enter your name when prompted
4. Click "Start Sharing" to share your screen
5. Select shared screens from the sidebar to view them

## Architecture

```
┌─────────────────────────────────────────────────────────────┐
│                      Signaling Server                        │
│                    (Rust/Axum/WebSocket)                     │
│  - Peer discovery                                            │
│  - Relays SDP offers/answers (with bundled candidates)       │
└─────────────────────────────────────────────────────────────┘
           │                                    │
           │ WebSocket                          │ WebSocket
           │ (signaling only)                   │ (signaling only)
           ▼                                    ▼
    ┌─────────────┐                      ┌─────────────┐
    │   Peer A    │◄────────────────────►│   Peer B    │
    │  (Browser)  │     Direct WebRTC    │  (Browser)  │
    └─────────────┘   (video/audio)      └─────────────┘
```

**100% Local Network** — No external services, simple direct connections:
- No STUN/TURN servers needed
- No trickle ICE — candidates bundled directly in SDP
- One offer + one answer = connected
- Video/audio streams stay entirely on your LAN

## Browser Support

Tested on:
- Chrome/Chromium
- Firefox
- Edge
- Safari (macOS)

Note: Screen sharing with audio requires Chrome/Edge on Windows/macOS. Firefox and Linux may have limited audio capture support depending on the system.

## Configuration

Command-line options take precedence over defaults. See `lanshare --help` for all options.

Environment variables:
- `RUST_LOG`: Override log level (e.g., `RUST_LOG=lanshare=debug`)

## Security Notes

- This is designed for **trusted local networks only**
- No authentication — anyone with the URL can join
- No encryption beyond what WebRTC provides by default (DTLS-SRTP)
- Don't expose to the internet without additional security measures

## License

MIT