applications: Add state trace source to OnOffApplication

CHANGES.md

@@ -18,6 +18,7 @@ This file is a best-effort approach to solving this issue; we will do our best b
 
 * (applications) Added two new base classes for source and sink applications, `SourceApplication` and `SinkApplication`, respectively.
 * (wifi) Changes have been made to the `WifiRemoteStationManager` interface for what concerns the update of the frame retry count of the MPDUs and the decision of dropping MPDUs (possibly based on the max retry limit). The `NeedRetransmission` method has been replaced by the `GetMpdusToDropOnTxFailure` method and the `DoNeedRetransmission` method has been replaced by the `DoGetMpdusToDropOnTxFailure` method. Also, the `DoIncrementRetryCountOnTxFailure` method has been added to implement custom policies for the update of the frame retry count of MPDUs upon transmission failure.
+* (applications) Added an `OnOffState` trace source to `OnOffApplication`, to track whether the application is transmitting or not.
 
 ### Changes to existing API
 

src/applications/model/onoff-application.cc

@@ -96,7 +96,11 @@ OnOffApplication::GetTypeId()
             .AddTraceSource("TxWithSeqTsSize",
                             "A new packet is created with SeqTsSizeHeader",
                             MakeTraceSourceAccessor(&OnOffApplication::m_txTraceWithSeqTsSize),
-                            "ns3::PacketSink::SeqTsSizeCallback");
+                            "ns3::PacketSink::SeqTsSizeCallback")
+            .AddTraceSource("OnOffState",
+                            "Application state (0-OFF, 1-ON)",
+                            MakeTraceSourceAccessor(&OnOffApplication::m_state),
+                            "ns3::TracedValueCallback::Bool");
     return tid;
 }
 
@@ -268,6 +272,7 @@ OnOffApplication::StartSending()
     m_lastStartTime = Simulator::Now();
     ScheduleNextTx(); // Schedule the send packet event
     ScheduleStopEvent();
+    m_state = true;
 }
 
 void
@@ -275,8 +280,8 @@ OnOffApplication::StopSending()
 {
     NS_LOG_FUNCTION(this);
     CancelEvents();
-
     ScheduleStartEvent();
+    m_state = false;
 }
 
 // Private helpers

src/applications/model/onoff-application.h

@@ -20,6 +20,7 @@
 #include "ns3/event-id.h"
 #include "ns3/ptr.h"
 #include "ns3/traced-callback.h"
+#include "ns3/traced-value.h"
 
 namespace ns3
 {
@@ -189,6 +190,8 @@ class OnOffApplication : public SourceApplication
      * @param socket the not connected socket
      */
     void ConnectionFailed(Ptr<Socket> socket);
+
+    TracedValue<bool> m_state; //!< State of application (0-OFF, 1-ON)
 };
 
 } // namespace ns3