wifi: Non-AP MLDs use a single beacon watchdog

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

@@ -814,14 +814,9 @@ StaWifiMac::ScanningTimeout(const std::optional<ApInfo>& bestAp)
     };
     Time beaconInterval = std::visit(getBeaconInterval, bestAp->m_frame);
     Time delay = beaconInterval * m_maxMissedBeacons;
-    // restart beacon watchdog for all links to setup
-    for (const auto& [id, link] : GetLinks())
-    {
-        if (GetStaLink(link).bssid.has_value() || GetNLinks() == 1)
-        {
-            RestartBeaconWatchdog(delay, id);
-        }
-    }
+    // restart beacon watchdog
+    RestartBeaconWatchdog(delay);
+
     SetState(WAIT_ASSOC_RESP);
     SendAssociationRequest(false);
 }
@@ -835,20 +830,19 @@ StaWifiMac::AssocRequestTimeout()
 }
 
 void
-StaWifiMac::MissedBeacons(uint8_t linkId)
+StaWifiMac::MissedBeacons()
 {
-    NS_LOG_FUNCTION(this << +linkId);
-    auto& link = GetLink(linkId);
-    if (link.beaconWatchdogEnd > Simulator::Now())
+    NS_LOG_FUNCTION(this);
+
+    if (m_beaconWatchdogEnd > Simulator::Now())
     {
-        if (link.beaconWatchdog.IsRunning())
+        if (m_beaconWatchdog.IsRunning())
         {
-            link.beaconWatchdog.Cancel();
+            m_beaconWatchdog.Cancel();
         }
-        link.beaconWatchdog = Simulator::Schedule(link.beaconWatchdogEnd - Simulator::Now(),
-                                                  &StaWifiMac::MissedBeacons,
-                                                  this,
-                                                  linkId);
+        m_beaconWatchdog = Simulator::Schedule(m_beaconWatchdogEnd - Simulator::Now(),
+                                               &StaWifiMac::MissedBeacons,
+                                               this);
         return;
     }
     NS_LOG_DEBUG("beacon missed");
@@ -856,9 +850,12 @@ StaWifiMac::MissedBeacons(uint8_t linkId)
     // a frame, wait until the RX is completed (otherwise, crashes may occur if
     // we are receiving a MU frame because its reception requires the STA-ID)
     Time delay = Seconds(0);
-    if (GetWifiPhy(linkId)->IsStateRx())
+    for (const auto& [id, link] : GetLinks())
     {
-        delay = GetWifiPhy(linkId)->GetDelayUntilIdle();
+        if (link->phy->IsStateRx())
+        {
+            delay = std::max(delay, link->phy->GetDelayUntilIdle());
+        }
     }
     Simulator::Schedule(delay, &StaWifiMac::Disassociated, this);
 }
@@ -890,15 +887,15 @@ StaWifiMac::Disassociated()
 }
 
 void
-StaWifiMac::RestartBeaconWatchdog(Time delay, uint8_t linkId)
+StaWifiMac::RestartBeaconWatchdog(Time delay)
 {
-    NS_LOG_FUNCTION(this << delay << +linkId);
-    auto& link = GetLink(linkId);
-    link.beaconWatchdogEnd = std::max(Simulator::Now() + delay, link.beaconWatchdogEnd);
-    if (Simulator::GetDelayLeft(link.beaconWatchdog) < delay && link.beaconWatchdog.IsExpired())
+    NS_LOG_FUNCTION(this << delay);
+
+    m_beaconWatchdogEnd = std::max(Simulator::Now() + delay, m_beaconWatchdogEnd);
+    if (Simulator::GetDelayLeft(m_beaconWatchdog) < delay && m_beaconWatchdog.IsExpired())
     {
         NS_LOG_DEBUG("really restart watchdog.");
-        link.beaconWatchdog = Simulator::Schedule(delay, &StaWifiMac::MissedBeacons, this, linkId);
+        m_beaconWatchdog = Simulator::Schedule(delay, &StaWifiMac::MissedBeacons, this);
     }
 }
 
@@ -1246,7 +1243,7 @@ StaWifiMac::ReceiveBeacon(Ptr<const WifiMpdu> mpdu, uint8_t linkId)
         m_beaconArrival(Simulator::Now());
         Time delay = MicroSeconds(std::get<MgtBeaconHeader>(apInfo.m_frame).GetBeaconIntervalUs() *
                                   m_maxMissedBeacons);
-        RestartBeaconWatchdog(delay, linkId);
+        RestartBeaconWatchdog(delay);
         UpdateApInfo(apInfo.m_frame, hdr.GetAddr2(), hdr.GetAddr3(), linkId);
     }
     else

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

@@ -357,8 +357,6 @@ class StaWifiMac : public WifiMac
         bool sendAssocReq;                 //!< whether this link is used to send the
                                            //!< Association Request frame
         std::optional<Mac48Address> bssid; //!< BSSID of the AP to associate with over this link
-        EventId beaconWatchdog;            //!< beacon watchdog
-        Time beaconWatchdogEnd{0};         //!< beacon watchdog end
         WifiPowerManagementMode pmMode{WIFI_PM_ACTIVE}; /**< the current PM mode, if the STA is
                                                              associated, or the PM mode to switch
                                                              to upon association, otherwise */
@@ -506,19 +504,15 @@ class StaWifiMac : public WifiMac
      */
     bool IsWaitAssocResp() const;
     /**
-     * This method is called after we have not received a beacon from the AP
-     * on the given link.
-     *
-     * \param linkId the ID of the given link
+     * This method is called after we have not received a beacon from the AP on any link.
      */
-    void MissedBeacons(uint8_t linkId);
+    void MissedBeacons();
     /**
-     * Restarts the beacon timer for the given link.
+     * Restarts the beacon timer.
      *
      * \param delay the delay before the watchdog fires
-     * \param linkId the ID of the given link
      */
-    void RestartBeaconWatchdog(Time delay, uint8_t linkId);
+    void RestartBeaconWatchdog(Time delay);
     /**
      * Set the state to unassociated and try to associate again.
      */
@@ -628,6 +622,8 @@ class StaWifiMac : public WifiMac
     Time m_assocRequestTimeout;             ///< association request timeout
     EventId m_assocRequestEvent;            ///< association request event
     uint32_t m_maxMissedBeacons;            ///< maximum missed beacons
+    EventId m_beaconWatchdog;               //!< beacon watchdog
+    Time m_beaconWatchdogEnd{0};            //!< beacon watchdog end
     bool m_activeProbing;                   ///< active probing
     Ptr<RandomVariableStream> m_probeDelay; ///< RandomVariable used to randomize the time
                                             ///< of the first Probe Response on each channel