wifi: Allow QosTxop to prepare Block Ack Requests for other ACs

src/wifi/model/block-ack-manager.cc

@@ -590,22 +590,27 @@ BlockAckManager::NotifyDiscardedMpdu (Ptr<const WifiMacQueueItem> mpdu)
   ScheduleBlockAckReq (recipient, tid);
 }
 
+CtrlBAckRequestHeader
+BlockAckManager::GetBlockAckReqHeader (Mac48Address recipient, uint8_t tid) const
+{
+  NS_LOG_FUNCTION (this << recipient << +tid);
+  AgreementsCI it = m_agreements.find (std::make_pair (recipient, tid));
+  NS_ASSERT (it != m_agreements.end ());
+
+  CtrlBAckRequestHeader reqHdr;
+  reqHdr.SetType (m_blockAckType);
+  reqHdr.SetTidInfo (tid);
+  reqHdr.SetStartingSequence ((*it).second.first.GetStartingSequence ());
+  return reqHdr;
+}
+
 void
 BlockAckManager::ScheduleBlockAckReq (Mac48Address recipient, uint8_t tid)
 {
   NS_LOG_FUNCTION (this << recipient << +tid);
-  AgreementsI it = m_agreements.find (std::make_pair (recipient, tid));
-  NS_ASSERT (it != m_agreements.end ());
-
-  OriginatorBlockAckAgreement &agreement = (*it).second.first;
-
-  CtrlBAckRequestHeader reqHdr;
-  reqHdr.SetType (m_blockAckType);
-  reqHdr.SetTidInfo (agreement.GetTid ());
-  reqHdr.SetStartingSequence (agreement.GetStartingSequence ());
 
   Ptr<Packet> bar = Create<Packet> ();
-  bar->AddHeader (reqHdr);
+  bar->AddHeader (GetBlockAckReqHeader (recipient, tid));
   WifiMacHeader hdr;
   hdr.SetAddr1 (recipient);
   hdr.SetType (WIFI_MAC_CTL_BACKREQ);

src/wifi/model/block-ack-manager.h

@@ -35,6 +35,7 @@ class WifiRemoteStationManager;
 class MgtAddBaResponseHeader;
 class MgtAddBaRequestHeader;
 class CtrlBAckResponseHeader;
+class CtrlBAckRequestHeader;
 class MacTxMiddle;
 class WifiMacQueue;
 class WifiMode;
@@ -388,6 +389,15 @@ public:
    */
   void NotifyDiscardedMpdu (Ptr<const WifiMacQueueItem> mpdu);
 
+  /**
+   * \param recipient the recipient
+   * \param tid the TID
+   *
+   * Get the block ack request header for the established BA agreement
+   * (<i>recipient</i>,<i>tid</i>).
+   */
+  CtrlBAckRequestHeader GetBlockAckReqHeader (Mac48Address recipient, uint8_t tid) const;
+
   /**
    * \param recipient the recipient
    * \param tid the TID

src/wifi/model/mac-low.cc

@@ -268,6 +268,14 @@ MacLow::ResetPhy (void)
   m_phy = 0;
 }
 
+Ptr<QosTxop>
+MacLow::GetEdca (uint8_t tid) const
+{
+  auto it = m_edca.find (QosUtilsMapTidToAc (tid));
+  NS_ASSERT (it != m_edca.end ());
+  return it->second;
+}
+
 void
 MacLow::SetMac (const Ptr<WifiMac> mac)
 {

src/wifi/model/mac-low.h

@@ -88,6 +88,11 @@ public:
    * Remove WifiPhy associated with this MacLow.
    */
   void ResetPhy (void);
+  /**
+   * \param tid the Traffic ID
+   * \return the QosTxop corresponding to the given TID
+   */
+  Ptr<QosTxop> GetEdca (uint8_t tid) const;
   /**
    * Set up WifiMac associated with this MacLow.
    *

src/wifi/model/qos-txop.cc

@@ -142,6 +142,27 @@ QosTxop::GetBaStartingSequence (Mac48Address address, uint8_t tid) const
   return m_baManager->GetOriginatorStartingSequence (address, tid);
 }
 
+Ptr<const WifiMacQueueItem>
+QosTxop::PrepareBlockAckRequest (Mac48Address recipient, uint8_t tid) const
+{
+  NS_LOG_FUNCTION (this << recipient << +tid);
+
+  CtrlBAckRequestHeader reqHdr = m_low->GetEdca (tid)->m_baManager->GetBlockAckReqHeader (recipient, tid);
+  Ptr<Packet> bar = Create<Packet> ();
+  bar->AddHeader (reqHdr);
+
+  WifiMacHeader hdr;
+  hdr.SetType (WIFI_MAC_CTL_BACKREQ);
+  hdr.SetAddr1 (recipient);
+  hdr.SetAddr2 (m_low->GetAddress ());
+  hdr.SetDsNotTo ();
+  hdr.SetDsNotFrom ();
+  hdr.SetNoRetry ();
+  hdr.SetNoMoreFragments ();
+
+  return Create<const WifiMacQueueItem> (bar, hdr);
+}
+
 void
 QosTxop::ScheduleBlockAckReq (Mac48Address address, uint8_t tid)
 {

src/wifi/model/qos-txop.h

@@ -185,6 +185,16 @@ public:
    * recipient for the given TID.
    */
   uint16_t GetBaStartingSequence (Mac48Address address, uint8_t tid) const;
+  /**
+   * \param recipient Address of recipient.
+   * \param tid Traffic ID.
+   *
+   * Prepare a Block Ack Request to be sent to <i>recipient</i> for Traffic ID
+   * <i>tid</i>. The header for the Block Ack Request is requested to the QosTxop
+   * corresponding to the given TID. A block ack agreement with the given recipient
+   * for the given TID must have been established by such QosTxop.
+   */
+  Ptr<const WifiMacQueueItem> PrepareBlockAckRequest (Mac48Address recipient, uint8_t tid) const;
   /**
    * \param address recipient address
    * \param tid traffic ID