Add upnp nat traversal

index.js

@@ -19,6 +19,7 @@ var randombytes = require('randombytes')
 var speedometer = require('speedometer')
 var zeroFill = require('zero-fill')
 
+var NatTraversal = require('./lib/nat-traversal') // browser exclude
 var TCPPool = require('./lib/tcp-pool') // browser exclude
 var Torrent = require('./lib/torrent')
 
@@ -106,6 +107,10 @@ function WebTorrent (opts) {
     if (global.WRTC && !self.tracker.wrtc) self.tracker.wrtc = global.WRTC
   }
 
+  if (typeof NatTraversal === 'function') {
+    self._natTraversal = new NatTraversal()
+  }
+
   if (typeof TCPPool === 'function') {
     self._tcpPool = new TCPPool(self)
   } else {
@@ -128,7 +133,12 @@ function WebTorrent (opts) {
 
     self.dht.once('listening', function () {
       var address = self.dht.address()
-      if (address) self.dhtPort = address.port
+      if (address) {
+        self.dhtPort = address.port
+        if (self._natTraversal) {
+          self._natTraversal.portMapping(self.dhtPort)
+        }
+      }
     })
 
     // Ignore warning when there are > 10 torrents in the client
@@ -425,6 +435,18 @@ WebTorrent.prototype._destroy = function (err, cb) {
     })
   }
 
+  if (self._natTraversal) {
+    tasks.push(function (cb) {
+      if (self.dhtPort) {
+        self._natTraversal.portUnMapping(self.dhtPort)
+      }
+      if (self.torrentPort) {
+        self._natTraversal.portUnMapping(self.torrentPort)
+      }
+      self._natTraversal.destroy(cb)
+    })
+  }
+
   parallel(tasks, cb)
 
   if (err) self.emit('error', err)
@@ -441,7 +463,12 @@ WebTorrent.prototype._onListening = function () {
     // Sometimes server.address() returns `null` in Docker.
     // WebTorrent issue: https://github.com/feross/bittorrent-swarm/pull/18
     var address = this._tcpPool.server.address()
-    if (address) this.torrentPort = address.port
+    if (address) {
+      this.torrentPort = address.port
+      if (this._natTraversal) {
+        this._natTraversal.portMapping(this.torrentPort)
+      }
+    }
   }
 
   this.emit('listening')

lib/nat-traversal.js

@@ -0,0 +1,69 @@
+
+module.exports = NatTraversal
+
+var debug = require('debug')('webtorrent:nat-traversal')
+var natUpnp = require('nat-upnp') // browser exclude
+
+function NatTraversal () {
+  var self = this
+
+  debug('Create UPnP client')
+  self._upnpClient = natUpnp.createClient()
+  self.ttl = 60 * 30
+  self.timeout = self.ttl - 60
+  self.intervals = {}
+}
+
+NatTraversal.prototype.portMapping = function (port, cb) {
+  var self = this
+
+  debug('Mapping port %d on router using UPnP', port)
+  self._upnpClient.portMapping({
+    public: port,
+    private: port,
+    description: 'WebTorrent',
+    ttl: self.ttl
+  }, function (err) {
+    if (err) {
+      return typeof cb === 'function' && cb(err)
+    }
+    self.intervals[port] = setInterval(NatTraversal.prototype.portMapping.bind(self, port), self.timeout)
+    debug('Port %d mapped on router using UPnP', port)
+    if (typeof cb === 'function') cb()
+  })
+}
+
+NatTraversal.prototype.portUnMapping = function (port, cb) {
+  var self = this
+  if (!self.intervals[port]) return typeof cb === 'function' && cb(new Error('Port not mapped'))
+
+  debug('Unmapping port %d on router using UPnP', port)
+  clearInterval(self.intervals[port])
+  delete self.intervals[port]
+
+  self._upnpClient.portUnmapping({
+    public: port
+  }, function (err) {
+    if (err) {
+      return typeof cb === 'function' && cb(err)
+    }
+    debug('Port %d unmapped on router using UPnP', port)
+    if (typeof cb === 'function') cb()
+  })
+}
+
+NatTraversal.prototype.destroy = function (cb) {
+  var self = this
+
+  // Clear all intervals
+  Object.keys(self.intervals).forEach(function (port) {
+    self.portUnMapping(port)
+  })
+
+  // Waiting next tick to prevent breaking some sockets
+  process.nextTick(function () {
+    self._upnpClient.close()
+    debug('UPnP client closed')
+    cb()
+  })
+}

package.json

@@ -8,11 +8,13 @@
     "url": "https://webtorrent.io"
   },
   "browser": {
+    "./lib/nat-traversal.js": false,
     "./lib/server.js": false,
     "./lib/tcp-pool.js": false,
     "bittorrent-dht/client": false,
     "fs-chunk-store": "memory-chunk-store",
     "load-ip-set": false,
+    "nat-upnp": false,
     "net": false,
     "os": false,
     "ut_pex": false
@@ -41,6 +43,7 @@
     "memory-chunk-store": "^1.2.0",
     "mime": "^1.3.4",
     "multistream": "^2.0.5",
+    "nat-upnp": "^1.0.4",
     "package-json-versionify": "^1.0.2",
     "parse-torrent": "^5.8.0",
     "pump": "^1.0.1",