From 8612d07e8b5558e9f1c9034ca062ee22366b3c2a Mon Sep 17 00:00:00 2001
From: Stefano Avallone <stavallo@unina.it>
Date: Tue, 9 Apr 2019 17:07:48 +0200
Subject: [PATCH] wifi: Handle packets ack'ed with Normal Ack under BA
 agreement

---
 src/wifi/model/block-ack-manager.cc | 70 +++++++++++++++++++++++++++++
 src/wifi/model/block-ack-manager.h  | 18 ++++++++
 src/wifi/model/qos-txop.cc          | 14 ++++++
 3 files changed, 102 insertions(+)

diff --git a/src/wifi/model/block-ack-manager.cc b/src/wifi/model/block-ack-manager.cc
index a2e6d5188..476a89182 100644
--- a/src/wifi/model/block-ack-manager.cc
+++ b/src/wifi/model/block-ack-manager.cc
@@ -502,6 +502,76 @@ BlockAckManager::AlreadyExists (uint16_t currentSeq, Mac48Address recipient, uin
   return false;
 }
 
+void
+BlockAckManager::NotifyGotAck (Ptr<const WifiMacQueueItem> mpdu)
+{
+  NS_LOG_FUNCTION (this << *mpdu);
+  NS_ASSERT (mpdu->GetHeader ().IsQosData ());
+
+  Mac48Address recipient = mpdu->GetHeader ().GetAddr1 ();
+  uint8_t tid = mpdu->GetHeader ().GetQosTid ();
+  NS_ASSERT (ExistsAgreementInState (recipient, tid, OriginatorBlockAckAgreement::ESTABLISHED));
+
+  AgreementsI it = m_agreements.find (std::make_pair (recipient, tid));
+  NS_ASSERT (it != m_agreements.end ());
+
+  // remove the acknowledged frame from the queue of outstanding packets
+  PacketQueueI queueIt = it->second.second.begin ();
+  while (queueIt != it->second.second.end ())
+    {
+      if ((*queueIt)->GetHeader ().GetSequenceNumber () == mpdu->GetHeader ().GetSequenceNumber ())
+        {
+          queueIt = it->second.second.erase (queueIt);
+        }
+      else
+      {
+        queueIt++;
+      }
+    }
+
+  uint16_t startingSeq = it->second.first.GetStartingSequence ();
+  if (mpdu->GetHeader ().GetSequenceNumber () == startingSeq)
+    {
+      // make the transmit window advance
+      it->second.first.SetStartingSequence ((startingSeq + 1) % 4096);
+    }
+}
+
+void
+BlockAckManager::NotifyMissedAck (Ptr<WifiMacQueueItem> mpdu)
+{
+  NS_LOG_FUNCTION (this << *mpdu);
+  NS_ASSERT (mpdu->GetHeader ().IsQosData ());
+
+  Mac48Address recipient = mpdu->GetHeader ().GetAddr1 ();
+  uint8_t tid = mpdu->GetHeader ().GetQosTid ();
+  NS_ASSERT (ExistsAgreementInState (recipient, tid, OriginatorBlockAckAgreement::ESTABLISHED));
+
+  AgreementsI it = m_agreements.find (std::make_pair (recipient, tid));
+  NS_ASSERT (it != m_agreements.end ());
+
+  // remove the frame from the queue of outstanding packets (it will be re-inserted
+  // if retransmitted)
+  PacketQueueI queueIt = it->second.second.begin ();
+  while (queueIt != it->second.second.end ())
+    {
+      if ((*queueIt)->GetHeader ().GetSequenceNumber () == mpdu->GetHeader ().GetSequenceNumber ())
+        {
+          queueIt = it->second.second.erase (queueIt);
+        }
+      else
+      {
+        queueIt++;
+      }
+    }
+
+  // insert in the retransmission queue
+  if (!AlreadyExists (mpdu->GetHeader ().GetSequenceNumber (), recipient, tid))
+    {
+      InsertInRetryQueue (mpdu);
+    }
+}
+
 void
 BlockAckManager::NotifyGotBlockAck (const CtrlBAckResponseHeader *blockAck, Mac48Address recipient, double rxSnr, WifiMode txMode, double dataSnr)
 {
diff --git a/src/wifi/model/block-ack-manager.h b/src/wifi/model/block-ack-manager.h
index fcf92d29c..76cf3be8d 100644
--- a/src/wifi/model/block-ack-manager.h
+++ b/src/wifi/model/block-ack-manager.h
@@ -179,6 +179,24 @@ public:
    *         false otherwise
    */
   bool HasPackets (void) const;
+  /**
+   * Invoked upon receipt of an ack frame after the transmission of a QoS data frame
+   * sent under an established Block Ack agreement. Remove the acknowledged frame
+   * from the outstanding packets and update the starting sequence number of the
+   * transmit window, if needed.
+   *
+   * \param mpdu The acknowledged MPDU.
+   */
+  void NotifyGotAck (Ptr<const WifiMacQueueItem> mpdu);
+  /**
+   * Invoked upon missed reception of an ack frame after the transmission of a
+   * QoS data frame sent under an established Block Ack agreement. Remove the
+   * acknowledged frame from the outstanding packets and insert it in the
+   * retransmission queue.
+   *
+   * \param mpdu The unacknowledged MPDU.
+   */
+  void NotifyMissedAck (Ptr<WifiMacQueueItem> mpdu);
   /**
    * \param blockAck The received block ack frame.
    * \param recipient Sender of block ack frame.
diff --git a/src/wifi/model/qos-txop.cc b/src/wifi/model/qos-txop.cc
index ca9fc59d2..636bc4204 100644
--- a/src/wifi/model/qos-txop.cc
+++ b/src/wifi/model/qos-txop.cc
@@ -872,6 +872,12 @@ QosTxop::GotAck (void)
                 }
             }
         }
+      if (m_currentHdr.IsQosData () && GetBaAgreementEstablished (m_currentHdr.GetAddr1 (), m_currentHdr.GetQosTid ()))
+        {
+          // notify the BA manager that the current packet was acknowledged
+          m_baManager->NotifyGotAck (Create<const WifiMacQueueItem> (m_currentPacket, m_currentHdr,
+                                                                     m_currentPacketTimestamp));
+        }
       m_currentPacket = 0;
       ResetCw ();
     }
@@ -955,6 +961,14 @@ QosTxop::MissedAck (void)
       m_stationManager->ReportDataFailed (m_currentHdr.GetAddr1 (), &m_currentHdr,
                                           m_currentPacket->GetSize ());
       m_currentHdr.SetRetry ();
+      if (m_currentHdr.IsQosData () && GetBaAgreementEstablished (m_currentHdr.GetAddr1 (), m_currentHdr.GetQosTid ()))
+        {
+          // notify the BA manager that the current packet was not acknowledged
+          m_baManager->NotifyMissedAck (Create<WifiMacQueueItem> (m_currentPacket, m_currentHdr,
+                                                                  m_currentPacketTimestamp));
+          // let the BA manager handle its retransmission
+          m_currentPacket = 0;
+        }
       UpdateFailedCw ();
       m_cwTrace = GetCw ();
     }