BT-143 and BT-144 : Fixed a corner case bug in qualifying a policy for...

BT-143 and BT-144 : Fixed a corner case bug in qualifying a policy for duplication-free-path, even if the policy has only one delivery port, if criteria for using duplication-free path is satisfied, then compute a duplication-free path [BT-143]. Introduced a barrier between clean-all-flows and subsequent flow-mod install messages to ensure reliable clean up of flow-table [BT-144].

src/main/java/net/floodlightcontroller/core/OFSwitchBase.java

@@ -48,6 +48,7 @@ import org.codehaus.jackson.annotate.JsonProperty;
 import org.codehaus.jackson.map.annotate.JsonSerialize;
 import org.codehaus.jackson.map.ser.ToStringSerializer;
 import org.jboss.netty.channel.Channel;
+import org.openflow.protocol.OFBarrierRequest;
 import org.openflow.protocol.OFFeaturesReply;
 import org.openflow.protocol.OFFlowMod;
 import org.openflow.protocol.OFMatch;
@@ -509,10 +510,18 @@ public abstract class OFSwitchBase implements IOFSwitch {
             .setCommand(OFFlowMod.OFPFC_DELETE)
             .setOutPort(OFPort.OFPP_NONE)
             .setLength(U16.t(OFFlowMod.MINIMUM_LENGTH));
+        fm.setXid(getNextTransactionId());
+        OFMessage barrierMsg = (OFBarrierRequest) 
+        		floodlightProvider.getOFMessageFactory().getMessage(
+        				OFType.BARRIER_REQUEST);
+        barrierMsg.setXid(getNextTransactionId());
         try {
             List<OFMessage> msglist = new ArrayList<OFMessage>(1);
             msglist.add(fm);
             channel.write(msglist);
+            msglist = new ArrayList<OFMessage>(1);
+            msglist.add(barrierMsg);
+            channel.write(msglist);
         } catch (Exception e) {
             log.error("Failed to clear all flows on switch " + this, e);
         }