Automatic connection recovery.

New configuration parameter: 'connection_recovery_min_interval' (seconds)
New configuration parameter: 'connection_recovery_max_interval' (seconds)

When all outbound proxies get unreachable, User Agent attemps to reconnect applying an
exponential backoff algorithm, which takes the minimum and maximum reconnection interval
values from those new configuration parameters.

Author: jmillan

src/Transport.js

@@ -239,16 +239,14 @@ JsSIP.Transport.prototype = {
 
     this.reconnection_attempts += 1;
 
-    if(this.reconnection_attempts > this.ua.configuration.max_reconnection) {
+    if(this.reconnection_attempts > this.ua.configuration.ws_server_max_reconnection) {
       console.log(JsSIP.c.LOG_TRANSPORT +'Maximum reconnection attempts for: ' + this.server.ws_uri);
       this.ua.onTransportError(this);
     } else {
       console.log(JsSIP.c.LOG_TRANSPORT +'Trying to reconnect to: ' + this.server.ws_uri + '. Reconnection attempt number ' + this.reconnection_attempts);
 
       this.reconnectTimer = window.setTimeout(function() {
-        transport.reConnect();}, this.ua.configuration.reconnection_timeout * 1000);
-
-      this.connect();
+        transport.connect();}, this.ua.configuration.ws_server_reconnection_timeout * 1000);
     }
   }
 };

src/UA.js

@@ -42,6 +42,8 @@ JsSIP.UA = function(configuration) {
     ict: {}
   };
 
+  this.transportRecoverAttempts = 0;
+
   /**
    * Load configuration
    *
@@ -61,17 +63,6 @@ JsSIP.UA.prototype = new JsSIP.EventEmitter();
 //  High Level API
 //=================
 
-/**
- * Notify the UA about network availability.
- */
-JsSIP.UA.prototype.networkIsReady = function() {
-  console.log('Network Ready notification received');
-  // Stablish connection if needed.
-  if(this.status === JsSIP.c.UA_STATUS_NOT_READY && this.error === JsSIP.c.UA_NETWORK_ERROR) {
-    this.transport.connect();
-  }
-};
-
 /**
  * Register.
  *
@@ -316,9 +307,14 @@ JsSIP.UA.prototype.onTransportError = function(transport) {
     new JsSIP.Transport(this, server);
   }else {
     this.closeSessionsOnTransportError();
-    this.status = JsSIP.c.UA_STATUS_NOT_READY;
-    this.error = JsSIP.c.UA_NETWORK_ERROR;
-    this.emit('disconnected');
+    if (!this.error || this.error !== JsSIP.c.UA_NETWORK_ERROR) {
+      this.status = JsSIP.c.UA_STATUS_NOT_READY;
+      this.error = JsSIP.c.UA_NETWORK_ERROR;
+      this.emit('disconnected');
+    }
+
+    // Transport Recovery process
+    this.recoverTransport();
   }
 };
 
@@ -331,6 +327,9 @@ JsSIP.UA.prototype.onTransportError = function(transport) {
 JsSIP.UA.prototype.onTransportConnected = function(transport) {
   this.transport = transport;
 
+  // Reset transport recovery counter
+  this.transportRecoverAttempts = 0;
+
   transport.server.status = JsSIP.c.WS_SERVER_READY;
   console.log(JsSIP.c.LOG_UA +'connection status set to: '+ JsSIP.c.WS_SERVER_READY);
 
@@ -569,6 +568,36 @@ JsSIP.UA.prototype.closeSessionsOnTransportError = function() {
   }
 };
 
+JsSIP.UA.prototype.recoverTransport = function(ua) {
+  var idx, k, nextRetry, count, server;
+
+  ua = ua || this;
+  count = ua.transportRecoverAttempts;
+
+  for (idx in ua.configuration.outbound_proxy_set) {
+    ua.configuration.outbound_proxy_set[idx].status = 0;
+  }
+
+  server = ua.getNextWsServer();
+
+  k = Math.floor((Math.random() * Math.pow(2,count)) +1);
+  nextRetry = k * ua.configuration.connection_recovery_min_interval;
+
+  if (nextRetry > ua.configuration.connection_recovery_max_interval) {
+    console.log(JsSIP.c.LOG_UA + 'Time for next connection attempt exceeds connection_recovery_max_interval. Resetting counter');
+    nextRetry = ua.configuration.connection_recovery_min_interval;
+    count = 0;
+  }
+
+  console.log(JsSIP.c.LOG_UA + 'Next connection attempt in: '+ nextRetry +' seconds');
+
+  window.setTimeout(
+    function(){
+      ua.transportRecoverAttempts = count + 1;
+      new JsSIP.Transport(ua, server);
+    }, nextRetry * 1000);
+};
+
 /**
  * Configuration load.
  * @private
@@ -592,8 +621,11 @@ JsSIP.UA.prototype.loadConfig = function(configuration) {
       register: true,
 
       // Transport related parameters
-      max_reconnection: 3,
-      reconnection_timeout: 4,
+      ws_server_max_reconnection: 3,
+      ws_server_reconnection_timeout: 4,
+
+      connection_recovery_min_interval: 2,
+      connection_recovery_max_interval: 30,
 
       // Session parameters
       no_answer_timeout: 60,
@@ -654,6 +686,14 @@ JsSIP.UA.prototype.loadConfig = function(configuration) {
     }
   }
 
+  // Sanity Checks
+
+  // Connection recovery intervals
+  if(settings.connection_recovery_max_interval < settings.connection_recovery_min_interval) {
+    console.error('"connection_recovery_max_interval" parameter is lower than "connection_recovery_min_interval"');
+    return false;
+  }
+
   // Post Configuration Process
 
   // Instance-id for GRUU
@@ -731,9 +771,13 @@ JsSIP.UA.configuration_skeleton = (function() {
       // Internal parameters
       "instance_id",
       "jssip_id",
-      "max_reconnection",
 
-      "reconnection_timeout",
+      "ws_server_max_reconnection",
+      "ws_server_reconnection_timeout",
+
+      "connection_recovery_min_interval",
+      "connection_recovery_max_interval",
+
       "register_min_expires",
 
       // Mandatory user configurable parameters
@@ -894,6 +938,24 @@ JsSIP.UA.configuration_check = {
         return true;
       }
     },
+    connection_recovery_min_interval: function(connection_recovery_min_interval) {
+      if(!Number(connection_recovery_min_interval)) {
+        return false;
+      } else if(connection_recovery_min_interval < 0) {
+        return false;
+      } else {
+        return true;
+      }
+    },
+    connection_recovery_max_interval: function(connection_recovery_max_interval) {
+      if(!Number(connection_recovery_max_interval)) {
+        return false;
+      } else if(connection_recovery_max_interval < 0) {
+        return false;
+      } else {
+        return true;
+      }
+    },
     hack_via_tcp: function(hack_via_tcp) {
       if(typeof hack_via_tcp !== 'boolean') {
         return false;