Allow proxy usage on tracker clients

README.md

@@ -72,6 +72,44 @@ var optionalOpts = {
       left: 0,
       customParam: 'blah' // custom parameters supported
     }
+  },
+
+  proxyOpts: {
+      // Socks proxy options (used to proxy requests in node)
+      socksProxy: {
+          // Configuration from socks module (https://github.com/JoshGlazebrook/socks)
+          proxy: {
+              // IP Address of Proxy (Required)
+              ipaddress: "1.2.3.4",
+              // TCP Port of Proxy (Required)
+              port: 1080,
+              // Proxy Type [4, 5] (Required)
+              // Note: 4 works for both 4 and 4a.
+              // Type 4 does not support UDP association relay 
+              type: 5,
+
+              // SOCKS 4 Specific:
+
+              // UserId used when making a SOCKS 4/4a request. (Optional)
+              userid: "someuserid",
+
+              // SOCKS 5 Specific:
+
+              // Authentication used for SOCKS 5 (when it's required) (Optional)
+              authentication: {
+                  username: "Josh",
+                  password: "somepassword"
+              }
+          },
+
+          // Amount of time to wait for a connection to be established. (Optional)
+          // - defaults to 10000ms (10 seconds)
+          timeout: 10000
+      },
+      // NodeJS HTTP agents (used to proxy HTTP and Websocket requests in node)
+      // Populated with Socks.Agent if socksProxy is provided
+      httpAgent: {},
+      httpsAgent: {}
   }
 }
 

client.js

@@ -31,6 +31,7 @@ inherits(Client, EventEmitter)
  * @param {function} opts.getAnnounceOpts        callback to provide data to tracker
  * @param {number} opts.rtcConfig                RTCPeerConnection configuration object
  * @param {number} opts.wrtc                     custom webrtc impl (useful in node.js)
+ * @param {object} opts.proxyOpts                proxy options (useful in node.js)
  */
 function Client (opts) {
   var self = this
@@ -63,6 +64,7 @@ function Client (opts) {
   self._rtcConfig = opts.rtcConfig
   self._wrtc = opts.wrtc
   self._getAnnounceOpts = opts.getAnnounceOpts
+  self._proxyOpts = opts.proxyOpts
 
   debug('new client %s', self.infoHash)
 

lib/client/http-tracker.js

@@ -2,10 +2,13 @@ module.exports = HTTPTracker
 
 var bencode = require('bencode')
 var compact2string = require('compact2string')
+var clone = require('clone')
 var debug = require('debug')('bittorrent-tracker:http-tracker')
 var extend = require('xtend')
 var get = require('simple-get')
 var inherits = require('inherits')
+var Socks = require('socks')
+var url = require('url')
 
 var common = require('../common')
 var Tracker = require('./tracker')
@@ -87,8 +90,19 @@ HTTPTracker.prototype.destroy = function (cb) {
 
 HTTPTracker.prototype._request = function (requestUrl, params, cb) {
   var self = this
-  var u = requestUrl + (requestUrl.indexOf('?') === -1 ? '?' : '&') +
-    common.querystringStringify(params)
+  var parsedUrl = url.parse(requestUrl + (requestUrl.indexOf('?') === -1 ? '?' : '&') + common.querystringStringify(params))
+  var agent
+  if (self.client._proxyOpts) {
+    agent = parsedUrl.protocol === 'https:'
+      ? self.client._proxyOpts.httpsAgent : self.client._proxyOpts.httpAgent
+    if (!agent && self.client._proxyOpts.socksProxy) {
+      agent = new Socks.Agent(clone(self.client._proxyOpts.socksProxy), (parsedUrl.protocol === 'https:'))
+    }
+  }
+  var u = {
+    url: parsedUrl,
+    agent: agent
+  }
 
   get.concat(u, function (err, res, data) {
     if (self.destroyed) return

lib/client/udp-tracker.js

@@ -2,11 +2,13 @@ module.exports = UDPTracker
 
 var BN = require('bn.js')
 var Buffer = require('safe-buffer').Buffer
+var clone = require('clone')
 var compact2string = require('compact2string')
 var debug = require('debug')('bittorrent-tracker:udp-tracker')
 var dgram = require('dgram')
 var inherits = require('inherits')
 var randombytes = require('randombytes')
+var Socks = require('socks')
 var url = require('url')
 
 var common = require('../common')
@@ -63,8 +65,42 @@ UDPTracker.prototype._request = function (opts) {
   var self = this
   if (!opts) opts = {}
   var parsedUrl = url.parse(self.announceUrl)
+  if (!parsedUrl.port) {
+    parsedUrl.port = 80
+  }
+  var timeout
+  // Socket used to connect to the socks server to create a relay, null if socks is disabled
+  var proxySocket
+  // Socket used to connect to the tracker or to the socks relay if socks is enabled
+  var socket
+  // Contains the host/port of the socks relay
+  var relay
   var transactionId = genTransactionId()
-  var socket = dgram.createSocket('udp4')
+
+  var proxyOpts = self.client._proxyOpts && clone(self.client._proxyOpts.socksProxy)
+  if (proxyOpts) {
+    if (!proxyOpts.proxy) {
+      proxyOpts.proxy = {}
+    }
+    // UDP requests uses the associate command
+    proxyOpts.proxy.command = 'associate'
+    if (!proxyOpts.target) {
+      // This should contain client IP and port but can be set to 0 if we don't have this information
+      proxyOpts.target = {
+        host: '0.0.0.0',
+        port: 0
+      }
+    }
+
+    if (proxyOpts.proxy.type === 5) {
+      Socks.createConnection(proxyOpts, onGotConnection)
+    } else {
+      debug('Ignoring Socks proxy for UDP request because type 5 is required')
+      onGotConnection(null)
+    }
+  } else {
+    onGotConnection(null)
+  }
 
   var cleanup = function () {
     if (!socket) return
@@ -78,29 +114,42 @@ 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)
 
-  // does not matter if `stopped` event arrives, so supress errors & cleanup after timeout
-  var ms = opts.event === 'stopped' ? TIMEOUT / 10 : TIMEOUT
-  var timeout = setTimeout(function () {
-    timeout = null
-    if (opts.event === 'stopped') cleanup()
-    else onError(new Error('tracker request timed out (' + opts.event + ')'))
-  }, ms)
-  if (timeout.unref) timeout.unref()
+  function onGotConnection (err, s, info) {
+    if (err) return onError(err)
+
+    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
+    timeout = setTimeout(function () {
+      timeout = null
+      if (opts.event === 'stopped') cleanup()
+      else onError(new Error('tracker request timed out (' + opts.event + ')'))
+    }, ms)
+    if (timeout.unref) timeout.unref()
 
-  send(Buffer.concat([
-    common.CONNECTION_ID,
-    common.toUInt32(common.ACTIONS.CONNECT),
-    transactionId
-  ]))
+    send(Buffer.concat([
+      common.CONNECTION_ID,
+      common.toUInt32(common.ACTIONS.CONNECT),
+      transactionId
+    ]), relay)
 
-  socket.on('error', onError)
-  socket.on('message', onSocketMessage)
+    socket.on('error', onError)
+    socket.on('message', onSocketMessage)
+  }
 
   function onSocketMessage (msg) {
     if (self.destroyed) return
+    if (proxySocket) msg = msg.slice(10)
     if (msg.length < 8 || msg.readUInt32BE(4) !== transactionId.readUInt32BE(0)) {
       return onError(new Error('tracker sent invalid transaction id'))
     }
@@ -180,11 +229,13 @@ UDPTracker.prototype._request = function (opts) {
     self.client.emit('warning', err)
   }
 
-  function send (message) {
-    if (!parsedUrl.port) {
-      parsedUrl.port = 80
+  function send (message, proxyInfo) {
+    if (proxyInfo) {
+      var pack = Socks.createUDPFrame({ host: parsedUrl.hostname, port: parsedUrl.port }, message)
+      socket.send(pack, 0, pack.length, proxyInfo.port, proxyInfo.host)
+    } else {
+      socket.send(message, 0, message.length, parsedUrl.port, parsedUrl.hostname)
     }
-    socket.send(message, 0, message.length, parsedUrl.port, parsedUrl.hostname)
   }
 
   function announce (connectionId, opts) {
@@ -204,7 +255,7 @@ UDPTracker.prototype._request = function (opts) {
       common.toUInt32(0), // key (optional)
       common.toUInt32(opts.numwant),
       toUInt16(self.client._port)
-    ]))
+    ]), relay)
   }
 
   function scrape (connectionId) {
@@ -219,7 +270,7 @@ UDPTracker.prototype._request = function (opts) {
       common.toUInt32(common.ACTIONS.SCRAPE),
       transactionId,
       infoHash
-    ]))
+    ]), relay)
   }
 }
 

lib/client/websocket-tracker.js

@@ -1,11 +1,14 @@
 module.exports = WebSocketTracker
 
+var clone = require('clone')
 var debug = require('debug')('bittorrent-tracker:websocket-tracker')
 var extend = require('xtend')
 var inherits = require('inherits')
 var Peer = require('simple-peer')
 var randombytes = require('randombytes')
 var Socket = require('simple-websocket')
+var Socks = require('socks')
+var url = require('url')
 
 var common = require('../common')
 var Tracker = require('./tracker')
@@ -167,7 +170,16 @@ WebSocketTracker.prototype._openSocket = function () {
   if (self.socket) {
     socketPool[self.announceUrl].consumers += 1
   } else {
-    self.socket = socketPool[self.announceUrl] = new Socket(self.announceUrl)
+    var parsedUrl = url.parse(self.announceUrl)
+    var agent
+    if (self.client._proxyOpts) {
+      agent = parsedUrl.protocol === 'wss:'
+        ? self.client._proxyOpts.httpsAgent : self.client._proxyOpts.httpAgent
+      if (!agent && self.client._proxyOpts.socksProxy) {
+        agent = new Socks.Agent(clone(self.client._proxyOpts.socksProxy), (parsedUrl.protocol === 'wss:'))
+      }
+    }
+    self.socket = socketPool[self.announceUrl] = new Socket(self.announceUrl, { agent: agent })
     self.socket.consumers = 1
     self.socket.on('connect', self._onSocketConnectBound)
   }

package.json

@@ -14,7 +14,8 @@
     "./lib/common-node.js": false,
     "./lib/client/http-tracker.js": false,
     "./lib/client/udp-tracker.js": false,
-    "./server.js": false
+    "./server.js": false,
+    "socks": false
   },
   "bugs": {
     "url": "https://github.com/feross/bittorrent-tracker/issues"
@@ -23,6 +24,7 @@
     "bencode": "^0.10.0",
     "bittorrent-peerid": "^1.0.2",
     "bn.js": "^4.4.0",
+    "clone": "^1.0.2",
     "compact2string": "^1.2.0",
     "debug": "^2.0.0",
     "inherits": "^2.0.1",
@@ -38,6 +40,7 @@
     "simple-get": "^2.0.0",
     "simple-peer": "^6.0.0",
     "simple-websocket": "^4.0.0",
+    "socks": "^1.1.9",
     "string2compact": "^1.1.1",
     "uniq": "^1.0.1",
     "ws": "^1.0.0",

test/client.js

@@ -2,6 +2,8 @@ var Buffer = require('safe-buffer').Buffer
 var Client = require('../')
 var common = require('./common')
 var fixtures = require('webtorrent-fixtures')
+var http = require('http')
+var net = require('net')
 var test = require('tape')
 
 var peerId1 = Buffer.from('01234567890123456789')
@@ -380,3 +382,56 @@ test('http: client announce with numwant', function (t) {
 test('udp: client announce with numwant', function (t) {
   testClientAnnounceWithNumWant(t, 'udp')
 })
+
+function testClientStartHttpAgent (t, serverType) {
+  t.plan(5)
+
+  common.createServer(t, serverType, function (server, announceUrl) {
+    var agent = new http.Agent()
+    var agentUsed = false
+    agent.createConnection = function (opts, fn) {
+      agentUsed = true
+      return net.createConnection(opts, fn)
+    }
+    var client = new Client({
+      infoHash: fixtures.leaves.parsedTorrent.infoHash,
+      announce: announceUrl,
+      peerId: peerId1,
+      port: port,
+      wrtc: {},
+      proxyOpts: {
+        httpAgent: agent
+      }
+    })
+
+    if (serverType === 'ws') common.mockWebsocketTracker(client)
+    client.on('error', function (err) { t.error(err) })
+    client.on('warning', function (err) { t.error(err) })
+
+    client.once('update', function (data) {
+      t.equal(data.announce, announceUrl)
+      t.equal(typeof data.complete, 'number')
+      t.equal(typeof data.incomplete, 'number')
+
+      t.ok(agentUsed)
+
+      client.stop()
+
+      client.once('update', function () {
+        t.pass('got response to stop')
+        server.close()
+        client.destroy()
+      })
+    })
+
+    client.start()
+  })
+}
+
+test('http: client.start(httpAgent)', function (t) {
+  testClientStartHttpAgent(t, 'http')
+})
+
+test('ws: client.start(httpAgent)', function (t) {
+  testClientStartHttpAgent(t, 'ws')
+})