Issue while Local Port Forwarding

[Gabriel-Hobart]

I'm following the forward_local.dart example, but I keep getting the following error no matter what I do.

StateError (Bad state: Stream was already listened to)
#0      _RawServerSocket.listen (dart:io-patch/socket_patch.dart:1770:7)
#1      new _ForwardingStreamSubscription (dart:async/stream_pipe.dart:114:10)
#2      _ForwardingStream._createSubscription (dart:async/stream_pipe.dart:86:16)
#3      _ForwardingStream.listen (dart:async/stream_pipe.dart:81:12)
#4      _ServerSocket.listen (dart:io-patch/socket_patch.dart:2053:71)
#5      _StreamIterator._initializeOrDone (dart:async/stream_impl.dart:942:33)
#6      _StreamIterator.moveNext (dart:async/stream_impl.dart:918:12)
#7      _MyHomePageState.sshConnect (package:vnc/main.dart)
<asynchronous suspension>

Here is a snippet of my code.

int port = 0;

  SSHClient? _client;
  SSHSocket? _socket;
  ServerSocket? _serverSocket;

  bool authenticated = false;
  bool forwarded = false;

  bool connect = false;

  sshConnect(String targetIp) async {
    bool result = false;
    Object? exception;
    try {
      _socket = await SSHSocket.connect(targetIp, 22);

      _client = SSHClient(_socket!,
          username: SSH_USER,
          onPasswordRequest: () => SSH_PASSWORD,
          onAuthenticated: () => setState(() => authenticated = true));

      await _client!.authenticated;

      _serverSocket = await ServerSocket.bind(LOCALHOST, port);
      print('Listening on ${_serverSocket!.address.address}:${_serverSocket!.port}');

      port = _serverSocket!.port;

      await for (final socket in _serverSocket!) {
        final forward = await _client!.forwardLocal("locahost", 5900,
            localHost: LOCALHOST, localPort: port);
        forward.stream.cast<List<int>>().pipe(socket);
        socket.cast<List<int>>().pipe(forward.sink);
      }
      result = true;
    } catch (e) {
      await _serverSocket!.close();
      _client!.close();
      await _client!.done;
      _socket!.close();
      await _socket!.done;
      result = false;
      exception = e;
    }

    setState(() {
      if (result) {
        forwarded = true;
      } else {
        connect = false;
        authenticated = false;
        forwarded = false;

        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            duration: const Duration(seconds: 30),
            content: Text('Error: $exception'),
          ),
        );
      }
    });
  }

  @override
  void dispose() {
    if (_client?.isClosed ?? false) _client!.close();
    if (_serverSocket != null) _serverSocket!.close();
    if (_socket != null) _socket!.close();
    super.dispose();
  }

[Gabriel-Hobart]

I'm running the code as a Windows app, and I have the dartssh2 2.9.1-pre package.

[Gabriel-Hobart]

A summarized version of the relevant code would be this.

     var _socket = await SSHSocket.connect(TARGET_IP, 22);

     var  _client = SSHClient(_socket,
          username: SSH_USER,
          onPasswordRequest: () => SSH_PASSWORD);

      await _client.authenticated;

      var _serverSocket = await ServerSocket.bind(LOCALHOST, 0);
      print('Listening on ${_serverSocket.address.address}:${_serverSocket.port}');

      await for (final socket in _serverSocket) {
        final forward = await _client!.forwardLocal("locahost", 5900,
            localHost: LOCALHOST, localPort:  _serverSocket.port);
        forward.stream.cast<List<int>>().pipe(socket);
        socket.cast<List<int>>().pipe(forward.sink);
      }