802.11: fix Greenfield control response handling

Keep operational mode membership pointer-strict while modeling mandatory PHY capabilities separately. Greenfield HT profiles now explicitly support non-HT and HT-mixed response modes without making those modes selectable for normal data transmission.

Apply IEEE 802.11-2024 control-response rules in DCF and QoS rate selection: ordinary HT ACK and Basic BlockAck responses use mandatory non-HT rates, CTS responses to HT-carried RTS frames use HT-mixed format, and configured response rates still derive their format from the eliciting PPDU. Preserve legacy and VHT override behavior and mandatory-rate fallback semantics.

Remove fuzzy public mode lookup, the mutable process-global response cache, and repeated global mode-table scans. Precompute immutable response mappings, make the mode-set registry thread-local to match HT mode ownership, and re-resolve configured response modes after mode-set changes.

Use explicit supported-mode validation for per-packet TX requests and RX feasibility while keeping default transmitter modes selectable and mode-set transitions atomic.

Add strict membership and transmitter transition unit coverage, configured and dynamic ACK/CTS/BlockAck checks, and a two-station forced RTS/CTS runtime regression that observes HT-GF RTS, HT-MF CTS, HT-GF data, and non-HT ACK frames.

Validated in debug mode with a clean build, 90/90 unit tests, 2/2 focused module tests, the HT-Greenfield example at 20/20 ping replies, and an unchanged focused fingerprint.

Author: mgonzalezlopezudc

src/inet/linklayer/ieee80211/mac/rateselection/QosRateSelection.cc

@@ -7,6 +7,8 @@
 
 #include "inet/linklayer/ieee80211/mac/rateselection/QosRateSelection.h"
 
+#include "inet/physicallayer/wireless/ieee80211/mode/Ieee80211HtMode.h"
+
 #include "inet/common/ModuleAccess.h"
 #include "inet/common/Simsignals.h"
 #include "inet/physicallayer/wireless/ieee80211/packetlevel/Ieee80211Tag_m.h"
@@ -16,6 +18,24 @@ namespace ieee80211 {
 
 using namespace inet::physicallayer;
 
+static const IIeee80211Mode *getConfiguredControlResponseMode(const Ieee80211ModeSet *modeSet, const IIeee80211Mode *mode)
+{
+    // Explicit legacy/VHT overrides retain their requested mode; HT rates need the
+    // bounded non-HT control-response conversion for ACK/BlockAck.
+    return dynamic_cast<const Ieee80211HtMode *>(mode) != nullptr ? modeSet->getNonHtControlResponseMode(mode) : mode;
+}
+
+static const IIeee80211Mode *getDynamicControlResponseMode(const Ieee80211ModeSet *modeSet, const IIeee80211Mode *mode)
+{
+    if (dynamic_cast<const Ieee80211HtMode *>(mode) != nullptr || !modeSet->containsMode(mode))
+        return modeSet->getNonHtControlResponseMode(mode);
+    if (modeSet->getIsMandatory(mode))
+        return mode;
+    if (auto slowerMode = modeSet->getSlowerMandatoryMode(mode))
+        return slowerMode;
+    return modeSet->getNonHtControlResponseMode(mode);
+}
+
 Define_Module(QosRateSelection);
 
 void QosRateSelection::initialize(int stage)
@@ -31,15 +51,22 @@ void QosRateSelection::initialize(int stage)
         mgmtFrameMode = (mgmtFrameBitrate == -1) ? nullptr : modeSet->getMode(bps(mgmtFrameBitrate));
         double controlFrameBitrate = par("controlFrameBitrate");
         controlFrameMode = (controlFrameBitrate == -1) ? nullptr : modeSet->getMode(bps(controlFrameBitrate));
-        double responseAckFrameBitrate = par("responseAckFrameBitrate");
-        responseAckFrameMode = (responseAckFrameBitrate == -1) ? nullptr : modeSet->getMode(bps(responseAckFrameBitrate));
-        double responseBlockAckFrameBitrate = par("responseBlockAckFrameBitrate");
-        responseBlockAckFrameMode = (responseBlockAckFrameBitrate == -1) ? nullptr : modeSet->getMode(bps(responseBlockAckFrameBitrate));
-        double responseCtsFrameBitrate = par("responseCtsFrameBitrate");
-        responseCtsFrameMode = (responseCtsFrameBitrate == -1) ? nullptr : modeSet->getMode(bps(responseCtsFrameBitrate));
+        resolveConfiguredResponseModes();
     }
 }
 
+void QosRateSelection::resolveConfiguredResponseModes()
+{
+    if (modeSet == nullptr)
+        return;
+    double responseAckFrameBitrate = par("responseAckFrameBitrate");
+    responseAckFrameMode = responseAckFrameBitrate == -1 ? nullptr : modeSet->getMode(bps(responseAckFrameBitrate));
+    double responseBlockAckFrameBitrate = par("responseBlockAckFrameBitrate");
+    responseBlockAckFrameMode = responseBlockAckFrameBitrate == -1 ? nullptr : modeSet->getMode(bps(responseBlockAckFrameBitrate));
+    double responseCtsFrameBitrate = par("responseCtsFrameBitrate");
+    responseCtsFrameMode = responseCtsFrameBitrate == -1 ? nullptr : modeSet->getMode(bps(responseCtsFrameBitrate));
+}
+
 const IIeee80211Mode *QosRateSelection::getMode(Packet *packet, const Ptr<const Ieee80211MacHeader>& header)
 {
     const auto& modeReqTag = packet->findTag<Ieee80211ModeReq>();
@@ -71,40 +98,25 @@ bool QosRateSelection::isControlResponseFrame(const Ptr<const Ieee80211MacHeader
 //
 const IIeee80211Mode *QosRateSelection::computeResponseAckFrameMode(Packet *packet, const Ptr<const Ieee80211DataOrMgmtHeader>& dataOrMgmtHeader)
 {
-    // TODO BSSBasicRateSet, alternate rate
+    if (responseAckFrameMode)
+        return getConfiguredControlResponseMode(modeSet, responseAckFrameMode);
     auto mode = getMode(packet, dataOrMgmtHeader);
-    ASSERT(modeSet->containsMode(mode));
-    if (!responseAckFrameMode) {
-        auto responseModeSet = modeSet->getControlResponseModeSet(mode);
-        auto responseMode = responseModeSet->getMode(mode);
-        if (responseModeSet->getIsMandatory(responseMode))
-            return responseMode;
-        else if (auto slowerMode = responseModeSet->getSlowerMandatoryMode(responseMode))
-            return slowerMode;
-        else
-            throw cRuntimeError("Mandatory mode not found");
-    }
-    else
-        return modeSet->getControlResponseMode(responseAckFrameMode);
+    ASSERT(modeSet->supportsMode(mode));
+    // IEEE 802.11-2024 10.6.6.1/10.6.6.5.2: this bounded model uses a
+    // mandatory non-HT rate for ordinary ACK responses; BSSBasicRateSet is not modelled.
+    return getDynamicControlResponseMode(modeSet, mode);
 }
 
 const IIeee80211Mode *QosRateSelection::computeResponseCtsFrameMode(Packet *packet, const Ptr<const Ieee80211RtsFrame>& rtsFrame)
 {
-    // TODO BSSBasicRateSet, alternate rate
     auto mode = getMode(packet, rtsFrame);
-    ASSERT(modeSet->containsMode(mode));
-    if (!responseCtsFrameMode) {
-        auto responseModeSet = modeSet->getControlResponseModeSet(mode);
-        auto responseMode = responseModeSet->getMode(mode);
-        if (responseModeSet->getIsMandatory(responseMode))
-            return responseMode;
-        else if (auto slowerMode = responseModeSet->getSlowerMandatoryMode(responseMode))
-            return slowerMode;
-        else
-            throw cRuntimeError("Mandatory mode not found");
+    ASSERT(modeSet->supportsMode(mode));
+    auto responseMode = responseCtsFrameMode ? responseCtsFrameMode : mode;
+    if (dynamic_cast<const Ieee80211HtMode *>(mode) != nullptr) {
+        // IEEE 802.11-2024 10.6.6.1 and 10.6.6.5.7 require an HT response to HT RTS; HT-GF is never a response.
+        return responseCtsFrameMode && dynamic_cast<const Ieee80211HtMode *>(responseMode) == nullptr ? responseMode : modeSet->getControlResponseMode(responseMode);
     }
-    else
-        return modeSet->getControlResponseMode(responseCtsFrameMode);
+    return responseCtsFrameMode ? getConfiguredControlResponseMode(modeSet, responseMode) : getDynamicControlResponseMode(modeSet, responseMode);
 }
 
 //
@@ -115,14 +127,17 @@ const IIeee80211Mode *QosRateSelection::computeResponseCtsFrameMode(Packet *pack
 //
 const IIeee80211Mode *QosRateSelection::computeResponseBlockAckFrameMode(Packet *packet, const Ptr<const Ieee80211BlockAckReq>& blockAckReq)
 {
-    if (dynamicPtrCast<const Ieee80211BasicBlockAckReq>(blockAckReq)) {
-        if (responseBlockAckFrameMode)
-            return modeSet->getControlResponseMode(responseBlockAckFrameMode);
-        else
-            return modeSet->getControlResponseMode(getMode(packet, blockAckReq));
-    }
-    else
+    if (!dynamicPtrCast<const Ieee80211BasicBlockAckReq>(blockAckReq))
         throw cRuntimeError("Unknown BlockAckReq frame type");
+    if (responseBlockAckFrameMode)
+        return getConfiguredControlResponseMode(modeSet, responseBlockAckFrameMode);
+    auto mode = getMode(packet, blockAckReq);
+    ASSERT(modeSet->supportsMode(mode));
+    // IEEE 802.11-2024 10.6.6.5.2 permits non-HT Basic BlockAck responses;
+    // this model has no BSSBasicRateSet/HT Control context to select another PPDU.
+    if (dynamic_cast<const Ieee80211HtMode *>(mode) != nullptr)
+        return modeSet->getNonHtControlResponseMode(mode);
+    return mode;
 }
 
 const IIeee80211Mode *QosRateSelection::computeDataOrMgmtFrameMode(const Ptr<const Ieee80211DataOrMgmtHeader>& dataOrMgmtHeader)
@@ -245,6 +260,7 @@ void QosRateSelection::receiveSignal(cComponent *source, simsignal_t signalID, c
     if (signalID == modesetChangedSignal) {
         modeSet = check_and_cast<Ieee80211ModeSet *>(obj);
         fastestMandatoryMode = modeSet->getFastestMandatoryMode();
+        resolveConfiguredResponseModes();
     }
 }
 

src/inet/linklayer/ieee80211/mac/rateselection/QosRateSelection.h

@@ -52,6 +52,7 @@ class INET_API QosRateSelection : public IQosRateSelection, public ModeSetListen
     virtual int numInitStages() const override { return NUM_INIT_STAGES; }
     virtual void initialize(int stage) override;
     virtual void receiveSignal(cComponent *source, simsignal_t signalID, cObject *obj, cObject *details) override;
+    void resolveConfiguredResponseModes();
 
     virtual const physicallayer::IIeee80211Mode *getMode(Packet *packet, const Ptr<const Ieee80211MacHeader>& header);
     virtual const physicallayer::IIeee80211Mode *computeControlFrameMode(const Ptr<const Ieee80211MacHeader>& header, TxopProcedure *txopProcedure);

src/inet/linklayer/ieee80211/mac/rateselection/RateSelection.cc

@@ -7,6 +7,8 @@
 
 #include "inet/linklayer/ieee80211/mac/rateselection/RateSelection.h"
 
+#include "inet/physicallayer/wireless/ieee80211/mode/Ieee80211HtMode.h"
+
 #include "inet/common/ModuleAccess.h"
 #include "inet/common/Simsignals.h"
 #include "inet/linklayer/ieee80211/mac/contract/IRateControl.h"
@@ -20,6 +22,24 @@ namespace ieee80211 {
 
 using namespace inet::physicallayer;
 
+static const IIeee80211Mode *getConfiguredControlResponseMode(const Ieee80211ModeSet *modeSet, const IIeee80211Mode *mode)
+{
+    // Explicit legacy/VHT overrides retain their requested mode; HT rates need the
+    // bounded non-HT control-response conversion for ACK/BlockAck.
+    return dynamic_cast<const Ieee80211HtMode *>(mode) != nullptr ? modeSet->getNonHtControlResponseMode(mode) : mode;
+}
+
+static const IIeee80211Mode *getDynamicControlResponseMode(const Ieee80211ModeSet *modeSet, const IIeee80211Mode *mode)
+{
+    if (dynamic_cast<const Ieee80211HtMode *>(mode) != nullptr || !modeSet->containsMode(mode))
+        return modeSet->getNonHtControlResponseMode(mode);
+    if (modeSet->getIsMandatory(mode))
+        return mode;
+    if (auto slowerMode = modeSet->getSlowerMandatoryMode(mode))
+        return slowerMode;
+    return modeSet->getNonHtControlResponseMode(mode);
+}
+
 Define_Module(RateSelection);
 
 void RateSelection::initialize(int stage)
@@ -37,10 +57,7 @@ void RateSelection::initialize(int stage)
         mgmtFrameMode = (mgmtFrameBitrate == -1) ? nullptr : modeSet->getMode(bps(mgmtFrameBitrate));
         double controlFrameBitrate = par("controlFrameBitrate");
         controlFrameMode = (controlFrameBitrate == -1) ? nullptr : modeSet->getMode(bps(controlFrameBitrate));
-        double responseAckFrameBitrate = par("responseAckFrameBitrate");
-        responseAckFrameMode = (responseAckFrameBitrate == -1) ? nullptr : modeSet->getMode(bps(responseAckFrameBitrate));
-        double responseCtsFrameBitrate = par("responseCtsFrameBitrate");
-        responseCtsFrameMode = (responseCtsFrameBitrate == -1) ? nullptr : modeSet->getMode(bps(responseCtsFrameBitrate));
+        resolveConfiguredResponseModes();
         fastestMandatoryMode = modeSet->getFastestMandatoryMode();
 //        WATCH(dataOrMgmtRateControl);
 
@@ -60,6 +77,16 @@ void RateSelection::initialize(int stage)
     }
 }
 
+void RateSelection::resolveConfiguredResponseModes()
+{
+    if (modeSet == nullptr)
+        return;
+    double responseAckFrameBitrate = par("responseAckFrameBitrate");
+    responseAckFrameMode = responseAckFrameBitrate == -1 ? nullptr : modeSet->getMode(bps(responseAckFrameBitrate));
+    double responseCtsFrameBitrate = par("responseCtsFrameBitrate");
+    responseCtsFrameMode = responseCtsFrameBitrate == -1 ? nullptr : modeSet->getMode(bps(responseCtsFrameBitrate));
+}
+
 const IIeee80211Mode *RateSelection::getMode(Packet *packet, const Ptr<const Ieee80211MacHeader>& header)
 {
     const auto& modeReqTag = packet->findTag<Ieee80211ModeReq>();
@@ -79,28 +106,27 @@ const IIeee80211Mode *RateSelection::getMode(Packet *packet, const Ptr<const Iee
 //
 const IIeee80211Mode *RateSelection::computeResponseAckFrameMode(Packet *packet, const Ptr<const Ieee80211DataOrMgmtHeader>& dataOrMgmtHeader)
 {
+    // Keep configured responses independent of the eliciting packet; callers may
+    // resolve a configured response while constructing a test packet.
     if (responseAckFrameMode)
-        return modeSet->getControlResponseMode(responseAckFrameMode);
-    else {
-        auto mode = getMode(packet, dataOrMgmtHeader);
-        ASSERT(modeSet->containsMode(mode));
-        auto responseModeSet = modeSet->getControlResponseModeSet(mode);
-        auto responseMode = responseModeSet->getMode(mode);
-        return responseModeSet->getIsMandatory(responseMode) ? responseMode : responseModeSet->getSlowerMandatoryMode(responseMode); // TODO BSSBasicRateSet
-    }
+        return getConfiguredControlResponseMode(modeSet, responseAckFrameMode);
+    auto mode = getMode(packet, dataOrMgmtHeader);
+    ASSERT(modeSet->supportsMode(mode));
+    // IEEE 802.11-2024 10.6.6.1/10.6.6.5.2: this bounded model uses a
+    // mandatory non-HT rate for ordinary ACK responses; BSSBasicRateSet is not modelled.
+    return getDynamicControlResponseMode(modeSet, mode);
 }
 
 const IIeee80211Mode *RateSelection::computeResponseCtsFrameMode(Packet *packet, const Ptr<const Ieee80211RtsFrame>& rtsFrame)
 {
-    if (responseCtsFrameMode)
-        return modeSet->getControlResponseMode(responseCtsFrameMode);
-    else {
-        auto mode = getMode(packet, rtsFrame);
-        ASSERT(modeSet->containsMode(mode));
-        auto responseModeSet = modeSet->getControlResponseModeSet(mode);
-        auto responseMode = responseModeSet->getMode(mode);
-        return responseModeSet->getIsMandatory(responseMode) ? responseMode : responseModeSet->getSlowerMandatoryMode(responseMode); // TODO BSSBasicRateSet
+    auto mode = getMode(packet, rtsFrame);
+    ASSERT(modeSet->supportsMode(mode));
+    auto responseMode = responseCtsFrameMode ? responseCtsFrameMode : mode;
+    if (dynamic_cast<const Ieee80211HtMode *>(mode) != nullptr) {
+        // IEEE 802.11-2024 10.6.6.1 and 10.6.6.5.7 require an HT response to HT RTS; HT-GF is never a response.
+        return responseCtsFrameMode && dynamic_cast<const Ieee80211HtMode *>(responseMode) == nullptr ? responseMode : modeSet->getControlResponseMode(responseMode);
     }
+    return responseCtsFrameMode ? getConfiguredControlResponseMode(modeSet, responseMode) : getDynamicControlResponseMode(modeSet, responseMode);
 }
 
 // 802.11-1999 Std.
@@ -157,6 +183,7 @@ void RateSelection::receiveSignal(cComponent *source, simsignal_t signalID, cObj
     if (signalID == modesetChangedSignal) {
         modeSet = check_and_cast<Ieee80211ModeSet *>(obj);
         fastestMandatoryMode = modeSet->getFastestMandatoryMode();
+        resolveConfiguredResponseModes();
     }
 }
 

src/inet/linklayer/ieee80211/mac/rateselection/RateSelection.h

@@ -52,6 +52,7 @@ class INET_API RateSelection : public IRateSelection, public SimpleModule, publi
     virtual int numInitStages() const override { return NUM_INIT_STAGES; }
     virtual void initialize(int stage) override;
     virtual void receiveSignal(cComponent *source, simsignal_t signalID, cObject *obj, cObject *details) override;
+    void resolveConfiguredResponseModes();
 
     virtual const physicallayer::IIeee80211Mode *getMode(Packet *packet, const Ptr<const Ieee80211MacHeader>& header);
     virtual const physicallayer::IIeee80211Mode *computeControlFrameMode(const Ptr<const Ieee80211MacHeader>& header);