wifi: Add StaWifiMac::BeaconArrival trace source

CHANGES.html

@@ -62,6 +62,7 @@ nodes to be placed outside of buildings defined in the scenario.</li>
   <li> The Hash() method has been added to the QueueDiscItem class to compute the
     hash of various fields of the packet header (depending on the packet type).</li>
   <li> Added a priority queue disc (PrioQueueDisc).</li>
+  <li> Added a new trace source in StaWifiMac for tracing beacon arrivals</li>
 </ul>
 <h2>Changes to existing API:</h2>
 <ul>

RELEASE_NOTES

@@ -29,6 +29,7 @@ New user-visible features
   The allocator places nodes randomly but in a manner that rejects positions
   that are located within buildings defined in the scenario.
 - (tcp) Added PRR as recovery algorithm
+- (wifi) Add a new trace source to StaWifiMac to trace beacon arrivals
 
 Bugs fixed
 ----------

src/wifi/model/sta-wifi-mac.cc

@@ -75,6 +75,10 @@ StaWifiMac::GetTypeId (void)
     .AddTraceSource ("DeAssoc", "Association with an access point lost.",
                      MakeTraceSourceAccessor (&StaWifiMac::m_deAssocLogger),
                      "ns3::Mac48Address::TracedCallback")
+    .AddTraceSource ("BeaconArrival",
+                     "Time of beacons arrival from associated AP",
+                     MakeTraceSourceAccessor (&StaWifiMac::m_beaconArrival),
+                     "ns3::Time::TracedCallback")
   ;
   return tid;
 }
@@ -604,6 +608,7 @@ StaWifiMac::Receive (Ptr<Packet> packet, const WifiMacHeader *hdr)
         }
       if (goodBeacon && m_state == ASSOCIATED)
         {
+          m_beaconArrival (Simulator::Now ());
           Time delay = MicroSeconds (beacon.GetBeaconIntervalUs () * m_maxMissedBeacons);
           RestartBeaconWatchdog (delay);
           UpdateApInfoFromBeacon (beacon, hdr->GetAddr2 (), hdr->GetAddr3 ());

src/wifi/model/sta-wifi-mac.h

@@ -318,6 +318,7 @@ private:
 
   TracedCallback<Mac48Address> m_assocLogger;   ///< assoc logger
   TracedCallback<Mac48Address> m_deAssocLogger; ///< deassoc logger
+  TracedCallback<Time>         m_beaconArrival; ///< beacon arrival logger
 };
 
 } //namespace ns3