Use new socket to connect to the proxy relay and slice the proxy header from the message

Author: yciabaud

lib/client/udp-tracker.js

@@ -68,7 +68,9 @@ UDPTracker.prototype._request = function (opts) {
     parsedUrl.port = 80
   }
   var timeout
+  var proxySocket
   var socket
+  var relay
   var transactionId = genTransactionId()
   if (self.client._socksProxyOpts) {
     if (!self.client._socksProxyOpts.proxy) {
@@ -84,9 +86,9 @@ UDPTracker.prototype._request = function (opts) {
       }
     }
 
-    Socks.createConnection(self.client._socksProxyOpts, onGotSocket)
+    Socks.createConnection(self.client._socksProxyOpts, onGotConnection)
   } else {
-    onGotSocket(null, dgram.createSocket('udp4'))
+    onGotConnection(null)
   }
 
   var cleanup = function () {
@@ -101,13 +103,19 @@ UDPTracker.prototype._request = function (opts) {
     socket.on('error', noop) // ignore all future errors
     try { socket.close() } catch (err) {}
     socket = null
+    if (proxySocket) {
+      try { proxySocket.close() } catch (err) {}
+      proxySocket = null
+    }
   }
   self.cleanupFns.push(cleanup)
 
-  function onGotSocket (err, s, info) {
+  function onGotConnection (err, s, info) {
     if (err) return onError(err)
 
-    socket = s
+    proxySocket = s
+    socket = dgram.createSocket('udp4')
+    relay = info
 
     // does not matter if `stopped` event arrives, so supress errors & cleanup after timeout
     var ms = opts.event === 'stopped' ? TIMEOUT / 10 : TIMEOUT
@@ -122,14 +130,15 @@ UDPTracker.prototype._request = function (opts) {
       common.CONNECTION_ID,
       common.toUInt32(common.ACTIONS.CONNECT),
       transactionId
-    ]), info)
+    ]), relay)
 
     socket.on('error', onError)
     socket.on('message', onSocketMessage)
   }
 
   function onSocketMessage (msg) {
     if (self.destroyed) return
+    if (self.client._socksProxyOpts) msg = msg.slice(10)
     if (msg.length < 8 || msg.readUInt32BE(4) !== transactionId.readUInt32BE(0)) {
       return onError(new Error('tracker sent invalid transaction id'))
     }
@@ -235,7 +244,7 @@ UDPTracker.prototype._request = function (opts) {
       common.toUInt32(0), // key (optional)
       common.toUInt32(opts.numwant),
       toUInt16(self.client._port)
-    ]))
+    ]), relay)
   }
 
   function scrape (connectionId) {
@@ -250,7 +259,7 @@ UDPTracker.prototype._request = function (opts) {
       common.toUInt32(common.ACTIONS.SCRAPE),
       transactionId,
       infoHash
-    ]))
+    ]), relay)
   }
 }