Merge pull request #334 from deathcap/legacyping

Server response to legacy ping (fe and fe01) packets

package.json

@@ -29,6 +29,7 @@
   "browser": "browser.js",
   "devDependencies": {
     "babel-preset-es2015": "^6.3.13",
+    "endian-toggle": "0.0.0",
     "espower-loader": "^1.0.0",
     "gulp": "^3.9.0",
     "gulp-babel": "^6.1.1",

src/client.js

@@ -14,6 +14,7 @@ class Client extends EventEmitter
     super();
     this.version=version;
     this.isServer = !!isServer;
+    this.splitter=framing.createSplitter();
     this.setSerializer(states.HANDSHAKING);
     this.packetsToParse={};
     this.serializer;
@@ -21,7 +22,6 @@ class Client extends EventEmitter
     this.framer=framing.createFramer();
     this.cipher=null;
     this.decipher=null;
-    this.splitter=framing.createSplitter();
     this.decompressor=null;
     this.deserializer;
     this.isServer;
@@ -51,6 +51,7 @@ class Client extends EventEmitter
     this.deserializer = createDeserializer({ isServer:this.isServer, version:this.version, state: state, packetsToParse:
       this.packetsToParse});
 
+    this.splitter.recognizeLegacyPing = state === states.HANDSHAKING;
 
     this.serializer.on('error', (e) => {
       var parts=e.field.split(".");

src/createServer.js

@@ -5,6 +5,7 @@ var states = require("./states");
 var bufferEqual = require('buffer-equal');
 var Server = require('./server');
 var UUID = require('uuid-1345');
+var endianToggle = require('endian-toggle');
 
 module.exports=createServer;
 
@@ -40,6 +41,7 @@ function createServer(options) {
     client.once('set_protocol', onHandshake);
     client.once('login_start', onLogin);
     client.once('ping_start', onPing);
+    client.once('legacy_server_list_ping', onLegacyPing);
     client.on('end', onEnd);
 
     var keepAlive = false;
@@ -126,6 +128,35 @@ function createServer(options) {
       });
     }
 
+    function onLegacyPing(packet) {
+      if (packet.payload === 1) {
+        var pingVersion = 1;
+        sendPingResponse('\xa7' + [pingVersion, version.version, version.minecraftVersion,
+            server.motd, server.playerCount.toString(), server.maxPlayers.toString()].join('\0'));
+      } else {
+        // ping type 0
+        sendPingResponse([server.motd, server.playerCount.toString(), server.maxPlayers.toString()].join('\xa7'));
+      }
+
+      function sendPingResponse(responseString) {
+        function utf16be(s) {
+          return endianToggle(new Buffer(s, 'utf16le'), 16);
+        }
+
+        var responseBuffer = utf16be(responseString);
+
+        var length = responseString.length; // UCS2 characters, not bytes
+        var lengthBuffer = new Buffer(2);
+        lengthBuffer.writeUInt16BE(length);
+
+        var raw = Buffer.concat([new Buffer('ff', 'hex'), lengthBuffer, responseBuffer]);
+
+        //client.writeRaw(raw); // not raw enough, it includes length
+        client.socket.write(raw);
+      }
+
+    }
+
     function onLogin(packet) {
       client.username = packet.username;
       var isException = !!server.onlineModeExceptions[client.username.toLowerCase()];

src/transforms/framing.js

@@ -23,13 +23,28 @@ class Framer extends Transform {
   }
 }
 
+const LEGACY_PING_PACKET_ID = 0xfe;
+
 class Splitter extends Transform {
   constructor() {
     super();
     this.buffer = new Buffer(0);
+    this.recognizeLegacyPing = false;
   }
   _transform(chunk, enc, cb) {
     this.buffer = Buffer.concat([this.buffer, chunk]);
+
+    if (this.recognizeLegacyPing && this.buffer[0] === LEGACY_PING_PACKET_ID) {
+      // legacy_server_list_ping packet follows a different protocol format
+      // prefix the encoded varint packet id for the deserializer
+      var header = new Buffer(sizeOfVarInt(LEGACY_PING_PACKET_ID));
+      writeVarInt(LEGACY_PING_PACKET_ID, header, 0);
+      var payload = this.buffer.slice(1); // remove 0xfe packet id
+      if (payload.length === 0) payload = new Buffer('\0'); // TODO: update minecraft-data to recognize a lone 0xfe, https://github.com/PrismarineJS/minecraft-data/issues/95
+      this.push(Buffer.concat([header, payload]));
+      return cb();
+    }
+
     var offset = 0;
 
     var { value, size, error } = readVarInt(this.buffer, offset) || { error: "Not enough data" };