wifi: Make DSSS Parameter Set IE optional in mgt frames

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

@@ -439,12 +439,9 @@ DsssParameterSet
 ApWifiMac::GetDsssParameterSet (uint8_t linkId) const
 {
   NS_LOG_FUNCTION (this << +linkId);
+  NS_ASSERT (GetDsssSupported (linkId));
   DsssParameterSet dsssParameters;
-  if (GetDsssSupported (linkId))
-    {
-      dsssParameters.SetDsssSupported (1);
-      dsssParameters.SetCurrentChannel (GetWifiPhy (linkId)->GetChannelNumber ());
-    }
+  dsssParameters.SetCurrentChannel (GetWifiPhy (linkId)->GetChannelNumber ());
   return dsssParameters;
 }
 

src/wifi/model/mgt-headers.cc

@@ -478,7 +478,7 @@ MgtProbeResponseHeader::SetDsssParameterSet (DsssParameterSet&& dsssParameterSet
   m_dsssParameterSet = std::move (dsssParameterSet);
 }
 
-const DsssParameterSet&
+const std::optional<DsssParameterSet>&
 MgtProbeResponseHeader::GetDsssParameterSet (void) const
 {
   return m_dsssParameterSet;
@@ -588,7 +588,7 @@ MgtProbeResponseHeader::GetSerializedSize (void) const
   size += m_capability.GetSerializedSize ();
   size += m_ssid.GetSerializedSize ();
   size += m_rates.GetSerializedSize ();
-  size += m_dsssParameterSet.GetSerializedSize ();
+  if (m_dsssParameterSet.has_value ()) size += m_dsssParameterSet->GetSerializedSize ();
   if (m_erpInformation.has_value ()) size += m_erpInformation->GetSerializedSize ();
   size += m_rates.extended.GetSerializedSize ();
   if (m_edcaParameterSet.has_value ()) size += m_edcaParameterSet->GetSerializedSize ();
@@ -631,7 +631,7 @@ MgtProbeResponseHeader::Serialize (Buffer::Iterator start) const
   i = m_capability.Serialize (i);
   i = m_ssid.Serialize (i);
   i = m_rates.Serialize (i);
-  i = m_dsssParameterSet.Serialize (i);
+  if (m_dsssParameterSet.has_value ()) i = m_dsssParameterSet->Serialize (i);
   if (m_erpInformation.has_value ()) i = m_erpInformation->Serialize (i);
   i = m_rates.extended.Serialize (i);
   if (m_edcaParameterSet.has_value ()) i = m_edcaParameterSet->Serialize (i);
@@ -658,7 +658,7 @@ MgtProbeResponseHeader::Deserialize (Buffer::Iterator start)
   i = m_capability.Deserialize (i);
   i = m_ssid.Deserialize (i);
   i = m_rates.Deserialize (i);
-  i = m_dsssParameterSet.DeserializeIfPresent (i);
+  i = WifiInformationElement::DeserializeIfPresent (m_dsssParameterSet, i);
   i = WifiInformationElement::DeserializeIfPresent (m_erpInformation, i);
   i = m_rates.extended.DeserializeIfPresent (i);
   i = WifiInformationElement::DeserializeIfPresent (m_edcaParameterSet, i);

src/wifi/model/mgt-headers.h

@@ -914,11 +914,11 @@ public:
    */
   const CapabilityInformation& GetCapabilities (void) const;
   /**
-   * Return the DSSS Parameter Set.
+   * Return the DSSS Parameter Set, if present.
    *
-   * \return the DSSS Parameter Set
+   * \return the DSSS Parameter Set, if present
    */
-  const DsssParameterSet& GetDsssParameterSet (void) const;
+  const std::optional<DsssParameterSet>& GetDsssParameterSet (void) const;
   /**
    * Return the extended capabilities, if present.
    *
@@ -1194,7 +1194,7 @@ private:
   uint64_t m_beaconInterval;           //!< Beacon interval
   SupportedRates m_rates;              //!< List of supported rates
   CapabilityInformation m_capability;  //!< Capability information
-  DsssParameterSet m_dsssParameterSet; //!< DSSS Parameter Set
+  std::optional<DsssParameterSet> m_dsssParameterSet; //!< DSSS Parameter Set
   std::optional<ExtendedCapabilities> m_extendedCapability; //!< extended capabilities
   std::optional<HtCapabilities> m_htCapability; //!< HT capabilities
   std::optional<HtOperation> m_htOperation;       //!< HT operation

src/wifi/model/non-ht/dsss-parameter-set.cc

@@ -23,8 +23,7 @@
 namespace ns3 {
 
 DsssParameterSet::DsssParameterSet ()
-  : m_currentChannel (0),
-    m_dsssSupported (0)
+  : m_currentChannel (0)
 {
 }
 
@@ -34,12 +33,6 @@ DsssParameterSet::ElementId () const
   return IE_DSSS_PARAMETER_SET;
 }
 
-void
-DsssParameterSet::SetDsssSupported (uint8_t dsssSupported)
-{
-  m_dsssSupported = dsssSupported;
-}
-
 void
 DsssParameterSet::SetCurrentChannel (uint8_t currentChannel)
 {
@@ -49,37 +42,13 @@ DsssParameterSet::SetCurrentChannel (uint8_t currentChannel)
 uint8_t
 DsssParameterSet::GetInformationFieldSize () const
 {
-  NS_ASSERT (m_dsssSupported);
   return 1;
 }
 
-Buffer::Iterator
-DsssParameterSet::Serialize (Buffer::Iterator i) const
-{
-  if (!m_dsssSupported)
-    {
-      return i;
-    }
-  return WifiInformationElement::Serialize (i);
-}
-
-uint16_t
-DsssParameterSet::GetSerializedSize () const
-{
-  if (!m_dsssSupported)
-    {
-      return 0;
-    }
-  return WifiInformationElement::GetSerializedSize ();
-}
-
 void
 DsssParameterSet::SerializeInformationField (Buffer::Iterator start) const
 {
-  if (m_dsssSupported)
-    {
-      start.WriteU8 (m_currentChannel);
-    }
+  start.WriteU8 (m_currentChannel);
 }
 
 uint8_t

src/wifi/model/non-ht/dsss-parameter-set.h

@@ -41,18 +41,6 @@ public:
   uint8_t GetInformationFieldSize () const override;
   void SerializeInformationField (Buffer::Iterator start) const override;
   uint8_t DeserializeInformationField (Buffer::Iterator start, uint8_t length) override;
-  /* This information element is a bit special in that it is only
-     included if the STA does support DSSS. To support this we
-     override the Serialize and GetSerializedSize methods of
-     WifiInformationElement. */
-  Buffer::Iterator Serialize (Buffer::Iterator start) const override;
-  uint16_t GetSerializedSize () const override;
-
-  /**
-   * Set DSSS supported
-   * \param dsssSupported the DSSS supported indicator
-   */
-  void SetDsssSupported (uint8_t dsssSupported);
 
   /**
    * Set the Current Channel field in the DsssParameterSet information element.
@@ -64,9 +52,6 @@ public:
 
 private:
   uint8_t m_currentChannel; ///< current channel number
-
-  /// This is used to decide whether this element should be added to the frame or not
-  bool m_dsssSupported;
 };
 
 } //namespace ns3