Close stale connection

If we stop getting keep-alive pings for some timeout period, close the
stale connection. This solves bug #31278 where chrome proxies hang open
on an idle connection.

config.js

@@ -31,6 +31,9 @@ Config.prototype.pollAdjustment = 300.0 * 1000;
 // Timeout after sending answer before datachannel is opened
 Config.prototype.datachannelTimeout = 20 * 1000;
 
+// Timeout to close proxypair if no messages are sent
+Config.prototype.messageTimeout = 30 * 1000;
+
 Config.prototype.maxNumClients = 1;
 
 Config.prototype.proxyType = "";

proxypair.js

@@ -16,7 +16,7 @@ class ProxyPair {
   - @relayAddr is the destination relay
   - @rateLimit specifies a rate limit on traffic
   */
-  constructor(relayAddr, rateLimit, pcConfig) {
+  constructor(relayAddr, rateLimit, config) {
     this.prepareDataChannel = this.prepareDataChannel.bind(this);
     this.connectRelay = this.connectRelay.bind(this);
     this.onClientToRelayMessage = this.onClientToRelayMessage.bind(this);
@@ -26,7 +26,8 @@ class ProxyPair {
 
     this.relayAddr = relayAddr;
     this.rateLimit = rateLimit;
-    this.pcConfig = pcConfig;
+    this.config = config;
+    this.pcConfig = config.pcConfig;
     this.id = Util.genSnowflakeID();
     this.c2rSchedule = [];
     this.r2cSchedule = [];
@@ -148,8 +149,19 @@ class ProxyPair {
 
   // WebRTC --> websocket
   onClientToRelayMessage(msg) {
+    if (this.messageTimer) {
+      clearTimeout(this.messageTimer);
+    }
     dbg('WebRTC --> websocket data: ' + msg.data.byteLength + ' bytes');
     this.c2rSchedule.push(msg.data);
+
+    // if we don't receive any keep-alive messages from the client, close the
+    // connection
+    this.messageTimer = setTimeout((() => {
+      console.log("Closing stale connection.");
+      this.flush()
+      this.close()
+    }), this.config.messageTimeout);
     return this.flush();
   }
 
@@ -173,6 +185,10 @@ class ProxyPair {
       clearTimeout(this.timer);
       this.timer = 0;
     }
+    if (this.messageTimer) {
+      clearTimeout(this.messageTimer);
+      this.messageTimer = 0;
+    }
     if (this.webrtcIsReady()) {
       this.client.close();
     }
@@ -244,6 +260,7 @@ ProxyPair.prototype.client = null; // WebRTC Data channel
 ProxyPair.prototype.relay = null; // websocket
 
 ProxyPair.prototype.timer = 0;
+ProxyPair.prototype.messageTimer = 0;
 ProxyPair.prototype.flush_timeout_id = null;
 
 ProxyPair.prototype.onCleanup = null;

snowflake.js

@@ -134,7 +134,7 @@ class Snowflake {
       return null;
     }
     var pair;
-    pair = new ProxyPair(this.relayAddr, this.rateLimit, this.config.pcConfig);
+    pair = new ProxyPair(this.relayAddr, this.rateLimit, this.config);
     this.proxyPairs.push(pair);
 
     log('Snowflake IDs: ' + (this.proxyPairs.map(function(p) {

spec/proxypair.spec.js

@@ -43,7 +43,7 @@ describe('ProxyPair', function() {
   destination = [];
 
   // Using the mock PeerConnection definition from spec/snowflake.spec.js
-  var pp = new ProxyPair(fakeRelay, rateLimit, config.pcConfig);
+  var pp = new ProxyPair(fakeRelay, rateLimit, config);
 
   beforeEach(function() {
     return pp.begin();