Peers now gossip about their neighbors when they talk.

core/src/main/scala/spark/BitTorrentBroadcast.scala

@@ -548,14 +548,24 @@ extends Broadcast[T] with Logging {
           var newPeerToTalkTo = oisSource.readObject.asInstanceOf[SourceInfo]
           // Update listOfSources
           addToListOfSources (newPeerToTalkTo)
-
+          
           // Turn the timer OFF, if the sender responds before timeout
           timeOutTimer.cancel
 
+          // Receive gossiped listOfSources and add to local list
+          var gossipedLOS = oisSource.readObject.asInstanceOf[ListBuffer[SourceInfo]]
+          addToListOfSources (gossipedLOS)
+
           // Send the latest SourceInfo
           oosSource.writeObject(getLocalSourceInfo)
           oosSource.flush
           
+          // Send gossiped listOfSources
+          listOfSources.synchronized {
+            oosSource.writeObject(listOfSources)
+          }
+          oosSource.flush
+          
           var keepReceiving = true
           
           while (hasBlocks < totalBlocks && keepReceiving) {
@@ -1017,15 +1027,24 @@ extends Broadcast[T] with Logging {
           oos.writeObject(getLocalSourceInfo)
           oos.flush
           
+          // Gossip local listOfSources
+          listOfSources.synchronized {
+            oos.writeObject(listOfSources)
+          }
+          oos.flush
+          
           // Receive latest SourceInfo from the receiver
           var rxSourceInfo = ois.readObject.asInstanceOf[SourceInfo]
-          // logInfo("rxSourceInfo: " + rxSourceInfo + " with " + rxSourceInfo.hasBlocksBitVector)
           
           if (rxSourceInfo.listenPort == SourceInfo.StopBroadcast) {
             stopBroadcast = true
           } else {
             // Carry on
             addToListOfSources (rxSourceInfo)
+
+            // Received gossiped listOfSources
+            var gossipedLOS = ois.readObject.asInstanceOf[ListBuffer[SourceInfo]]
+            addToListOfSources (gossipedLOS)
           }
           
           val startTime = System.currentTimeMillis