node-rcon.js

/*!
 * node-rcon
 * Copyright(c) 2012 Justin Li <j-li.net>
 * MIT Licensed
 */

var util = require('util')
  , events = require('events')
  , net = require('net')
  , dgram = require('dgram')
  , Buffer = require('buffer').Buffer;


var PacketType = {
  COMMAND: 0x02,
  AUTH: 0x03,
  RESPONSE_VALUE: 0x00,
  RESPONSE_AUTH: 0x02
};

/**
 * options:
 *   tcp - true for TCP, false for UDP (optional, default true)
 *   challenge - if using UDP, whether to use the challenge protocol (optional, default true)
 *   id - RCON id to use (optional)
 */
function Rcon(host, port, password, options) {
  if (!(this instanceof Rcon)) return new Rcon(host, port, password, options);
  options = options || {};

  this.host = host;
  this.port = port;
  this.password = password;
  this.rconId = options.id || 0x0012D4A6; // This is arbitrary in most cases
  this.hasAuthed = false;
  this.outstandingData = null;
  this.tcp = options.tcp == null ? true : options.tcp;
  this.challenge = options.challenge == null ? true : options.challenge;

  events.EventEmitter.call(this);
};

util.inherits(Rcon, events.EventEmitter);

Rcon.prototype.send = function(data, cmd, id) {
  var sendBuf;
  if (this.tcp) {
    cmd = cmd || PacketType.COMMAND;
    id = id || this.rconId;

    var length = Buffer.byteLength(data);
    sendBuf = Buffer.alloc(length + 14);
    sendBuf.writeInt32LE(length + 10, 0);
    sendBuf.writeInt32LE(id, 4);
    sendBuf.writeInt32LE(cmd, 8);
    sendBuf.write(data, 12);
    sendBuf.writeInt16LE(0, length + 12);
  } else {
    if (this.challenge && !this._challengeToken) {
      this.emit('error', new Error('Not authenticated'));
      return;
    }
    var str = "rcon ";
    if (this._challengeToken) str += this._challengeToken + " ";
    if (this.password) str += this.password + " ";
    str += data + "\n";
    sendBuf = Buffer.alloc(4 + Buffer.byteLength(str));
    sendBuf.writeInt32LE(-1, 0);
    sendBuf.write(str, 4)
  }
  this._sendSocket(sendBuf);
};

Rcon.prototype._sendSocket = function(buf) {
  if (this._tcpSocket) {
    this._tcpSocket.write(buf.toString('binary'), 'binary');
  } else if (this._udpSocket) {
    this._udpSocket.send(buf, 0, buf.length, this.port, this.host);
  }
};

Rcon.prototype.connect = function() {
  var self = this;

  if (this.tcp) {
    this._tcpSocket = net.createConnection(this.port, this.host);
    this._tcpSocket.on('data', function(data) { self._tcpSocketOnData(data) })
                   .on('connect', function() { self.socketOnConnect() })
                   .on('error', function(err) { self.emit('error', err) })
                   .on('end', function() { self.socketOnEnd() });
  } else {
    this._udpSocket = dgram.createSocket("udp4");
    this._udpSocket.on('message', function(data) { self._udpSocketOnData(data) })
                   .on('listening', function() { self.socketOnConnect() })
                   .on('error', function(err) { self.emit('error', err) })
                   .on('close', function() { self.socketOnEnd() });
    this._udpSocket.bind(0);
  }
};

Rcon.prototype.disconnect = function() {
  if (this._tcpSocket) this._tcpSocket.end();
  if (this._udpSocket) this._udpSocket.close();
};

Rcon.prototype.setTimeout = function(timeout, callback) {
  if (!this._tcpSocket) return;

  var self = this;
  this._tcpSocket.setTimeout(timeout, function() {
    self._tcpSocket.end();
    if (callback) callback();
  });
};

Rcon.prototype._udpSocketOnData = function(data) {
  var a = data.readUInt32LE(0);
  if (a == 0xffffffff) {
    var str = data.toString("utf-8", 4);
    var tokens = str.split(" ");
    if (tokens.length == 3 && tokens[0] == "challenge" && tokens[1] == "rcon") {
      this._challengeToken = tokens[2].substr(0, tokens[2].length - 1).trim();
      this.hasAuthed = true;
      this.emit('auth');
    } else {
      this.emit('response', str.substr(1, str.length - 2));
    }
  } else {
    this.emit('error', new Error("Received malformed packet"));
  }
}

Rcon.prototype._tcpSocketOnData = function(data) {
  if (this.outstandingData != null) {
    data = Buffer.concat([this.outstandingData, data], this.outstandingData.length + data.length);
    this.outstandingData = null;
  }

  while (data.length >= 12) {
    var len = data.readInt32LE(0); // Size of entire packet, not including the 4 byte length field
    if (!len) return; // No valid packet header, discard entire buffer

    var packetLen = len + 4;
    if (data.length < packetLen) break; // Wait for full packet, TCP may have segmented it

    var bodyLen = len - 10; // Subtract size of ID, type, and two mandatory trailing null bytes
    if (bodyLen < 0) {
      data = data.slice(packetLen); // Length is too short, discard malformed packet
      break;
    }

    var id = data.readInt32LE(4);
    var type = data.readInt32LE(8);

    if (id == this.rconId) {
      if (!this.hasAuthed && type == PacketType.RESPONSE_AUTH) {
        this.hasAuthed = true;
        this.emit('auth');
      } else if (type == PacketType.RESPONSE_VALUE) {
        // Read just the body of the packet (truncate the last null byte)
        // See https://developer.valvesoftware.com/wiki/Source_RCON_Protocol for details
        var str = data.toString('utf8', 12, 12 + bodyLen);

        if (str.charAt(str.length - 1) === '\n') {
          // Emit the response without the newline.
          str = str.substring(0, str.length - 1);
        }

        this.emit('response', str);
      }
    } else if (id == -1) {
      this.emit('error', new Error("Authentication failed"));
    } else {
      // ping/pong likely
      var str = data.toString('utf8', 12, 12 + bodyLen);

      if (str.charAt(str.length - 1) === '\n') {
        // Emit the response without the newline.
        str = str.substring(0, str.length - 1);
      }

      this.emit('server', str);
    }

    data = data.slice(packetLen);
  }

  // Keep a reference to remaining data, since the buffer might be split within a packet
  this.outstandingData = data;
};

Rcon.prototype.socketOnConnect = function() {
  this.emit('connect');

  if (this.tcp) {
    this.send(this.password, PacketType.AUTH);
  } else if (this.challenge) {
    var str = "challenge rcon\n";
    var sendBuf = Buffer.alloc(str.length + 4);
    sendBuf.writeInt32LE(-1, 0);
    sendBuf.write(str, 4);
    this._sendSocket(sendBuf);
  } else {
    var sendBuf = Buffer.alloc(5);
    sendBuf.writeInt32LE(-1, 0);
    sendBuf.writeUInt8(0, 4);
    this._sendSocket(sendBuf);

    this.hasAuthed = true;
    this.emit('auth');
  }
};

Rcon.prototype.socketOnEnd = function() {
  this.emit('end');
  this.hasAuthed = false;
};

module.exports = Rcon;