gophertunnel

The main.go file demonstrates how to build a Man-in-the-Middle (MITM) proxy that forwards Minecraft players from a local address to a remote address.

Key steps in the proxy lifecycle:

1. Authentication: Use auth.RequestLiveToken() to obtain a token and auth.RefreshTokenSource(token) to create an oauth2.TokenSource.
2. Status Provider: Initialize a minecraft.NewForeignStatusProvider using the remote address to handle status requests.
3. Listening: Use minecraft.ListenConfig with a StatusProvider to start a listener on a specific protocol (e.g., "raknet") and local address.
4. Connection Handling: For every accepted connection, use minecraft.Dialer to connect to the remote server, passing the TokenSource and the client's ClientData().
5. Session Initialization: Synchronize the game state by calling conn.StartGame(serverConn.GameData()) on the client connection and serverConn.DoSpawn() on the server connection.
6. Packet Forwarding: Run two concurrent loops to read packets from the client and write them to the server, and vice versa, ensuring minecraft.DisconnectError is handled to disconnect the client gracefully.

// Simplified proxy logic flow
// 1. Setup Listener
p, _ := minecraft.NewForeignStatusProvider(remoteAddr)
listener, _ := minecraft.ListenConfig{StatusProvider: p}.Listen("raknet", localAddr)

// 2. Handle Connections
for {
	conn, _ := listener.Accept()
	go func(c *minecraft.Conn) {
		// 3. Dial Remote
		serverConn, _ := minecraft.Dialer{
			TokenSource: src,
			ClientData:  c.ClientData(),
		}.Dial("raknet", remoteAddr)

		// 4. Initialize Game
		_ = c.StartGame(serverConn.GameData())
		_ = serverConn.DoSpawn()

		// 5. Forward Packets (Client -> Server)
		// ... loop conn.ReadPacket() -> serverConn.WritePacket(pk)

		// 6. Forward Packets (Server -> Client)
		// ... loop serverConn.ReadPacket() -> c.WritePacket(pk)
	}(conn.(*minecraft.Conn))
}