EthernetMacPhy: Add optional support for emitting the receptionStarted signal

added new NED receptionMode parameter: "onStart" | "auto" | "onEnd" | "forceOnEnd"

Author: ZoltanBojthe

src/inet/linklayer/ethernet/basic/EthernetMacPhy.cc

@@ -30,17 +30,56 @@ EthernetMacPhy::EthernetMacPhy()
 {
 }
 
+EthernetMacPhy::~EthernetMacPhy()
+{
+    cancelAndDelete(endRxTimer);
+    delete currentRxSignal;
+}
+
 void EthernetMacPhy::initialize(int stage)
 {
     EthernetMacBase::initialize(stage);
 
     if (stage == INITSTAGE_LOCAL) {
+        // read parameters
         if (!par("duplexMode"))
             throw cRuntimeError("Half duplex operation is not supported by EthernetMacPhy, use the EthernetCsmaMacPhy module for that! (Please enable csmacdSupport on EthernetInterface)");
+
+        const char *receptionModeStr = par("receptionMode");
+        if (!strcmp(receptionModeStr, "onStart"))
+            receptionMode = ON_START;
+        else if (!strcmp(receptionModeStr, "auto"))
+            receptionMode = AUTO;
+        else if (!strcmp(receptionModeStr, "onEnd"))
+            receptionMode = ON_END;
+        else if (!strcmp(receptionModeStr, "forceOnEnd"))
+            receptionMode = FORCE_ON_END;
+        else
+            throw cRuntimeError("Unknown receptionMode value '%s'", receptionModeStr);
+
     }
     else if (stage == INITSTAGE_LINK_LAYER) {
         beginSendFrames(); // FIXME choose an another stage for it
     }
+    else if (stage == INITSTAGE_LAST) {
+        switch (receptionMode) {
+            case ON_START:
+                setReceptionOnStartMode();
+                break;
+            case AUTO:
+                if (hasListeners(receptionStartedSignal))
+                    setReceptionOnStartMode();
+                break;
+            case ON_END:
+                if (hasListeners(receptionStartedSignal))
+                    throw cRuntimeError("Signal 'receptionStartedSignal' has active listeners subscribed, but the signal's release is disabled via parameter 'emitReceptionStarted' = false. Remove the listeners or set the parameter to true.");
+                break;
+            case FORCE_ON_END:
+                break;
+            default:
+                throw cRuntimeError("Unknown receptionMode value '%d'", (int)receptionMode);
+        }
+    }
 }
 
 void EthernetMacPhy::initializeStatistics()
@@ -51,12 +90,19 @@ void EthernetMacPhy::initializeStatistics()
     totalSuccessfulRxTime = 0.0;
 }
 
+void EthernetMacPhy::setReceptionOnStartMode()
+{
+    endRxTimer = new cMessage("EndReception", ENDRECEPTION);
+    setTxUpdateSupport(true);
+    physInGate->setDeliverImmediately(true);
+    receptionOnStart = true;
+}
+
 void EthernetMacPhy::initializeFlags()
 {
     EthernetMacBase::initializeFlags();
 
     duplexMode = true;
-    physInGate->setDeliverImmediately(false);
 }
 
 void EthernetMacPhy::handleMessageWhenUp(cMessage *msg)
@@ -68,8 +114,31 @@ void EthernetMacPhy::handleMessageWhenUp(cMessage *msg)
         handleSelfMessage(msg);
     else if (msg->getArrivalGateId() == upperLayerInGateId)
         handleUpperPacket(check_and_cast<Packet *>(msg));
-    else if (msg->getArrivalGate() == physInGate)
-        processMsgFromNetwork(check_and_cast<Signal *>(msg));
+    else if (msg->getArrivalGate() == physInGate) {
+        Signal *signal = check_and_cast<Signal *>(msg);
+        if (receptionOnStart) {
+            if (signal->isUpdate()) {
+                ASSERT(endRxTimer->isScheduled());
+                ASSERT(currentRxSignal != nullptr);
+                EV_DETAIL << "Rx update: " << signal << endl;
+                delete currentRxSignal;
+                currentRxSignal = signal;
+                rescheduleAfter(currentRxSignal->getRemainingDuration(), endRxTimer);
+            }
+            else {
+                EV_DETAIL << "Rx start: " << signal << endl;
+                ASSERT(!endRxTimer->isScheduled());
+                ASSERT(currentRxSignal == nullptr);
+                simtime_t remainingDuration = signal->getRemainingDuration();
+                currentRxSignal = signal;
+                scheduleAfter(remainingDuration, endRxTimer);
+                emit(receptionStartedSignal, signal);
+            }
+        }
+        else {
+            processMsgFromNetwork(signal);
+        }
+    }
     else
         throw cRuntimeError("Message received from unknown gate!");
     processAtHandleMessageFinished();
@@ -85,6 +154,12 @@ void EthernetMacPhy::handleSelfMessage(cMessage *msg)
         handleEndIFGPeriod();
     else if (msg == endPauseTimer)
         handleEndPausePeriod();
+    else if (msg == endRxTimer) {
+        EV_DETAIL << "Rx end: " << currentRxSignal << endl;
+        processMsgFromNetwork(currentRxSignal);
+        currentRxSignal = nullptr;
+        processAtHandleMessageFinished();
+    }
     else
         throw cRuntimeError("Unknown self message received!");
 }

src/inet/linklayer/ethernet/basic/EthernetMacPhy.h

@@ -22,11 +22,14 @@ class INET_API EthernetMacPhy : public EthernetMacBase
 {
   public:
     EthernetMacPhy();
+    virtual ~EthernetMacPhy();
 
     // IActivePacketSink:
     virtual void handleCanPullPacketChanged(const cGate *gate) override;
 
   protected:
+    enum ReceptionMode {ON_START, AUTO, ON_END, FORCE_ON_END};
+
     virtual int numInitStages() const override { return NUM_INIT_STAGES; }
     virtual void initialize(int stage) override;
     virtual void initializeStatistics() override;
@@ -43,6 +46,7 @@ class INET_API EthernetMacPhy : public EthernetMacBase
     virtual void handleSelfMessage(cMessage *msg) override;
 
     // helpers
+    virtual void setReceptionOnStartMode();
     virtual void startFrameTransmission();
     virtual void handleUpperPacket(Packet *pk) override;
     virtual void processMsgFromNetwork(Signal *signal);
@@ -52,6 +56,17 @@ class INET_API EthernetMacPhy : public EthernetMacBase
     virtual void scheduleEndPausePeriod(int pauseUnits);
     virtual void beginSendFrames();
 
+    // parameter values
+    ReceptionMode receptionMode = AUTO;
+
+    bool receptionOnStart = false;
+
+    // self messages
+    cMessage *endRxTimer = nullptr;
+
+    // other variables
+    Signal *currentRxSignal = nullptr;
+
     // statistics
     simtime_t totalSuccessfulRxTime; // total duration of successful transmissions on channel
 };

src/inet/linklayer/ethernet/basic/EthernetMacPhy.ned

@@ -115,6 +115,14 @@ module EthernetMacPhy extends Module like IEtherMac
         bool duplexMode;                    // Must be set to "true", as EthernetMacPhy does not support half-duplex operation
                                             // (parameter is present to reduce the risk of accidental misconfiguration)
         bool allowNonstandardBitrate = default(false); // Allows any bitrate and uses the first larger bitrate specified parameters
+
+        // Receiviving mode of incoming ethernet frames:
+        //   - onStart: receiving on start of frame
+        //   - auto: receiving on start frame when module has any subscribers to receptionStart signal, otherwise receiving on end of frame
+        //   - onEnd: receiving on end of frame, throws error at end of initialize module when has any subscribers to receptionStart signal
+        //   - forceOnEnd: receiving on end of frame, silently skip emit receptionStart signal
+        string receptionMode @enum("onStart", "auto", "onEnd", "forceOnEnd") = default("auto");
+
         int mtu @unit(B) = default(1500B);
         string fcsMode @enum("declared", "computed");
         @lifecycleSupport;
@@ -137,6 +145,7 @@ module EthernetMacPhy extends Module like IEtherMac
         @signal[receptionStateChanged](type=long); // Enum=MacReceiveState
         @signal[transmissionStarted](type=inet::physicallayer::EthernetSignalBase);
         @signal[transmissionEnded](type=inet::physicallayer::EthernetSignalBase);
+        @signal[receptionStarted](type=inet::physicallayer::Signal);
         @signal[receptionEnded](type=inet::physicallayer::Signal);
 
         @statistic[transmitting](title="transmitting state"; type=int; source=count(transmissionStarted) - count(transmissionEnded); record=vector; interpolationmode=sample-hold);