[tor-commits] [snowflake-webext/master] Close stale connection

[cohosh at torproject.org]

commit 4100963928c13ffe66e78a4eed689b21ba018a2c
Author: Cecylia Bocovich <cohosh at torproject.org>
Date:   Thu May 7 13:22:20 2020 -0400

    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              |  3 +++
 proxypair.js           | 21 +++++++++++++++++++--
 snowflake.js           |  2 +-
 spec/proxypair.spec.js |  2 +-
 4 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/config.js b/config.js
index 3f632ca..8c67532 100644
--- a/config.js
+++ b/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 = "";
diff --git a/proxypair.js b/proxypair.js
index afcacb1..1153ee3 100644
--- a/proxypair.js
+++ b/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;
diff --git a/snowflake.js b/snowflake.js
index be475ec..1021c78 100644
--- a/snowflake.js
+++ b/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) {
diff --git a/spec/proxypair.spec.js b/spec/proxypair.spec.js
index f15d6d2..992b4c1 100644
--- a/spec/proxypair.spec.js
+++ b/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();