Adds a periodic check that triggers a disconnect if a half-open connection is detected.

jicoco/src/main/java/org/jitsi/xmpp/mucclient/MucClient.java

@@ -48,11 +48,13 @@
  */
 public class MucClient
 {
+    private static final int DEFAULT_PING_INTERVAL_SECONDS = 30;
+
     static
     {
         XMPPTCPConnection.setUseStreamManagementDefault(false);
         XMPPTCPConnection.setUseStreamManagementResumptionDefault(false);
-        PingManager.setDefaultPingInterval(30);
+        PingManager.setDefaultPingInterval(DEFAULT_PING_INTERVAL_SECONDS);
     }
 
     /**
@@ -795,7 +797,7 @@ private void removePresenceExtension(String elementName, String namespace)
                 {
                     return;
                 }
-                
+
                 if (lastPresenceSent.removeExtension(elementName, namespace) != null)
                 {
                     updatedPresence = lastPresenceSent.build();
@@ -853,4 +855,49 @@ public void pingFailed()
             }
         }
     }
+
+    private final PeriodicRunnable halfOpenConnectionPeriodicCheck = new HalfOpenConnectionPeriodicCheck();
+
+    /**
+     * @return the {@link PeriodicRunnable} that checks the XMPP connection state and triggers a disconnect if a
+     * half-open connection is detected.
+     */
+    public PeriodicRunnable getHalfOpenConnectionPeriodicCheck()
+    {
+        return halfOpenConnectionPeriodicCheck;
+    }
+
+    /**
+     * Periodically checks the connection state and triggers a disconnect if a half-open connection is detected.
+     */
+    class HalfOpenConnectionPeriodicCheck
+        extends PeriodicRunnable
+    {
+        public HalfOpenConnectionPeriodicCheck() {
+            super(2*1000*DEFAULT_PING_INTERVAL_SECONDS);
+        }
+
+        /**
+         * Triggers a disconnect if a half-open connection is detected.
+         */
+        @Override
+        public void run() {
+            super.run();
+
+            AbstractXMPPConnection con = xmppConnection;
+            if (con != null && con.isConnected() && con.isAuthenticated())
+            {
+                long lastStanzaReceivedMs = con.getLastStanzaReceived();
+                if (lastStanzaReceivedMs > 0)
+                {
+                    long nowMs = System.currentTimeMillis();
+                    if (nowMs - lastStanzaReceivedMs > 2 * 1000 * DEFAULT_PING_INTERVAL_SECONDS)
+                    {
+                        logger.warn("Half-open XMPP connection detected, will trigger a disconnect.");
+                        con.disconnect();
+                    }
+                }
+            }
+        }
+    }
 }

jicoco/src/main/java/org/jitsi/xmpp/mucclient/MucClientManager.java

@@ -17,6 +17,7 @@
 package org.jitsi.xmpp.mucclient;
 
 import org.jitsi.service.configuration.*;
+import org.jitsi.utils.concurrent.*;
 import org.jitsi.utils.logging2.*;
 import org.jitsi.utils.logging2.Logger;
 import org.jivesoftware.smack.*;
@@ -79,6 +80,11 @@ public class MucClientManager
      */
     private final Object syncRoot = new Object();
 
+    /**
+     * The {@link RecurringRunnableExecutor} to be utilized by the {@link MucClientManager} class and its instances.
+     */
+    private final RecurringRunnableExecutor recurringRunnableExecutor = new RecurringRunnableExecutor();
+
     /**
      * Initializes a new {@link MucClientManager} instance.
      *
@@ -126,6 +132,7 @@ public boolean addMucClient(MucClientConfiguration config)
 
             mucClient = new MucClient(config, MucClientManager.this);
             mucClients.put(config.getId(), mucClient);
+            recurringRunnableExecutor.registerRecurringRunnable(mucClient.getHalfOpenConnectionPeriodicCheck());
         }
 
         mucClient.start();
@@ -325,7 +332,8 @@ public boolean removeMucClient(String id)
            logger.info("Can not find MucClient to remove.");
            return false;
        }
-       mucClient.stop();
+        recurringRunnableExecutor.deRegisterRecurringRunnable(mucClient.getHalfOpenConnectionPeriodicCheck());
+        mucClient.stop();
        return true;
     }