Ice Data Channel

Ice Data Channel is a lightweight signaling server and client library for establishing UDP peer-to-peer connections between clients behind NAT, using the ICE protocol.

This library enables NAT traversal via ICE and simplifies the setup process with a built-in signaling server over WebSockets.

Features

• Built-in signaling server (WebSocket-based)
• ICE support for NAT traversal
• Peer-to-peer UDP communication
• Simple and clean API for clients
• Minimal dependencies

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Example

Full Example

func main() {
	l, err := net.Listen("tcp", "localhost:9090")
	if err != nil {
		panic(err)
	}

	// Start signaling server
	go server.Serve(l, "/ws")

	cfg := client.DefaultConfig("localhost:9090", "/ws")

	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	// Room owner listens for guests
	owner, err := client.NewOwner(ctx, OnConnect, cfg)
	if err != nil {
		panic(err)
	}

	//6 character room ID. Example: ABC123
	fmt.Println("created room with id", owner.RoomID)
	
	// Guest joins using the owner's room ID
	guest, err := client.NewGuest(ctx, owner.RoomID, cfg)
	if err != nil {
		panic(err)
	}

	// Peer-to-peer connection established!
	for range 5 {
		time.Sleep(time.Second)
		payload, err := json.Marshal(time.Now())
		if err != nil {
			panic("failed to marshal time")
		}
		guest.Conn().Write(payload)
	}

	select {} // keep alive
}

func OnConnect(conn client.Conn) {
	var buf [1500]byte
	fmt.Println("new connection!")
	for {
		n, err := conn.Read(buf[:])
		if err != nil {
			fmt.Println(err)
			close(exit)
			return
		}
		t := time.Time{}
		err = json.Unmarshal(buf[:n], &t)
		if err != nil {
			panic("failed to unmarshal time " + err.Error())
		}
		fmt.Println(time.Since(t))
	}
}

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How It Works

Here's a great presentation that explains how ice works and why we need it

1. Start a Signaling Server The signaling server uses WebSockets to allow clients to discover and exchange ICE candidates.

2. Client Connection

   • One peer becomes the owner, opening a room.
   • Other peers join as a guest using the owner's room ID.
   • Both exchange ICE candidates through the signaling server.

3. P2P Connection Once ICE negotiation is complete, a direct UDP connection is established between peers. The signaling server is no longer involved for sending traffic. It only listens for more peers that want to connect, and kicks inactive peers

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Usage

1. Run a signaling server (publicly accessible).
2. Use client.NewOwner() to create a host.
3. Use client.NewGuest() to connect to the host with the provided room ID.
4. Send and receive data using *ice.Conn.

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TODO

• Figure out what to do

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📄 License

MIT © BrownNPC

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