From 35c12eb14afbdd5d90b0692a61435993c18559cf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Deronne?= <sebastien.deronne@gmail.com>
Date: Sun, 11 Dec 2016 16:23:26 +0100
Subject: [PATCH] wifi: (fixes #2463) Add TxopTrace trace source to EdcaTxopN

---
 CHANGES.html                  |  1 +
 RELEASE_NOTES                 |  1 +
 src/wifi/model/edca-txop-n.cc | 17 ++++++++++++++++-
 src/wifi/model/edca-txop-n.h  |  1 +
 src/wifi/test/wifi-test.cc    |  3 +++
 5 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/CHANGES.html b/CHANGES.html
index e03e75787..1d429599f 100644
--- a/CHANGES.html
+++ b/CHANGES.html
@@ -58,6 +58,7 @@ us a note on ns-developers mailing list.</p>
     parameter to specify the time units used on the report.  The new parameter is
     optional and if not specified defaults to the previous behavior (Time::S).
 </li>
+<li><b>TxopTrace</b>: new trace source exported by EdcaTxopN.</li>
 </ul>
 <h2>Changes to existing API:</h2>
 <ul>
diff --git a/RELEASE_NOTES b/RELEASE_NOTES
index 3294ec877..a4479c9b3 100644
--- a/RELEASE_NOTES
+++ b/RELEASE_NOTES
@@ -27,6 +27,7 @@ Bugs fixed
 - Bug 2007 - uan: Remove deprecation on SetRxThresholdDb
 - Bug 2221 - network: Remove constraint on size of ns3::Packet Tag objects
 - Bug 2450 - LogDistancePropagationLossModel is not continuous
+- Bug 2463 - create trace source to trace the TXOP time that is actually used
 - Bug 2477 - DCF manager assert
 - Bug 2492 - uan: Make use of RxGain attribute in UanPhyGen class
 - Bug 2511 - HT Greenfield is not working
diff --git a/src/wifi/model/edca-txop-n.cc b/src/wifi/model/edca-txop-n.cc
index 622ff63fe..0c6eaa383 100644
--- a/src/wifi/model/edca-txop-n.cc
+++ b/src/wifi/model/edca-txop-n.cc
@@ -248,6 +248,10 @@ EdcaTxopN::GetTypeId (void)
                      "Trace source for contention window values",
                      MakeTraceSourceAccessor (&EdcaTxopN::m_cwTrace),
                      "ns3::TracedValue::Uint32Callback")
+    .AddTraceSource ("TxopTrace",
+                     "Trace source for txop start and duration times",
+                     MakeTraceSourceAccessor (&EdcaTxopN::m_txopTrace),
+                     "ns3::TracedValueCallback::Time")
   ;
   return tid;
 }
@@ -1184,9 +1188,10 @@ void
 EdcaTxopN::StartNext (void)
 {
   NS_LOG_FUNCTION (this);
+  NS_ASSERT (GetTxopLimit () == NanoSeconds (0) || Simulator::Now () - m_startTxop <= GetTxopLimit ());
+
   WifiMacHeader hdr;
   Time tstamp;
-
   Ptr<const Packet> peekedPacket = m_queue->PeekByTidAndAddress (&hdr,
                                                                  m_currentHdr.GetQosTid (),
                                                                  WifiMacHeader::ADDR1,
@@ -1194,6 +1199,11 @@ EdcaTxopN::StartNext (void)
                                                                  &tstamp);
   if (peekedPacket == 0)
     {
+      if (GetTxopLimit () > NanoSeconds (0))
+        {
+          NS_ASSERT (Simulator::Now () - m_startTxop <= GetTxopLimit ());
+          m_txopTrace (m_startTxop, Simulator::Now () - m_startTxop);
+        }
       return;
     }
     
@@ -1227,6 +1237,11 @@ EdcaTxopN::StartNext (void)
                                                          m_currentHdr.GetAddr1 ());
       GetLow ()->StartTransmission (m_currentPacket, &m_currentHdr, params, m_transmissionListener);
     }
+  else if (GetTxopLimit () > NanoSeconds (0))
+    {
+      NS_ASSERT (Simulator::Now () - m_startTxop <= GetTxopLimit ());
+      m_txopTrace (m_startTxop, Simulator::Now () - m_startTxop);
+    }
 }
 
 Time
diff --git a/src/wifi/model/edca-txop-n.h b/src/wifi/model/edca-txop-n.h
index d743de7cb..49972dd92 100644
--- a/src/wifi/model/edca-txop-n.h
+++ b/src/wifi/model/edca-txop-n.h
@@ -579,6 +579,7 @@ private:
   bool m_isAccessRequestedForRts;
   TracedValue<uint32_t> m_backoffTrace;
   TracedValue<uint32_t> m_cwTrace;
+  TracedCallback<Time, Time> m_txopTrace;
 };
 
 } //namespace ns3
diff --git a/src/wifi/test/wifi-test.cc b/src/wifi/test/wifi-test.cc
index 5aeb2753c..00d8fd564 100644
--- a/src/wifi/test/wifi-test.cc
+++ b/src/wifi/test/wifi-test.cc
@@ -1023,6 +1023,9 @@ Bug2222TestCase::DoRun (void)
   phy.SetChannel (channel.Create ());
 
   WifiHelper wifi;
+  wifi.SetRemoteStationManager ("ns3::ConstantRateWifiManager",
+                                "DataMode", StringValue ("OfdmRate54Mbps"),
+                                "ControlMode", StringValue ("OfdmRate24Mbps"));
   WifiMacHelper mac;
   Ssid ssid = Ssid ("ns-3-ssid");
   mac.SetType ("ns3::AdhocWifiMac",