fix(ieee80211): answer valid compressed block ack requests

Remove the recipient-side peer capability assumption from compressed Block Ack response selection. An addressed, syntactically valid one-TID compressed BlockAckReq must receive a compressed BlockAck after SIFS, including the all-zero response when no matching partial state exists, as required by IEEE 802.11-2024 sections 9.3.1.7.2 and 10.25.6.5.

Keep the originator-side capability assumption as the explicit opt-in for selecting compressed BlockAckReq frames until per-peer HT capability management is modeled. Continue rejecting nonzero fragment numbers and suppressing immediate responses for unaccepted or delayed agreements.

Update the focused unit and runtime coverage to verify null-state responses, malformed fragment rejection, agreement-policy gates, and asymmetric endpoint configuration.

Author: mgonzalezlopezudc

src/inet/linklayer/ieee80211/mac/recipient/RecipientQosAckPolicy.cc

@@ -18,10 +18,8 @@ Define_Module(RecipientQosAckPolicy);
 void RecipientQosAckPolicy::initialize(int stage)
 {
     ModeSetListener::initialize(stage);
-    if (stage == INITSTAGE_LOCAL) {
+    if (stage == INITSTAGE_LOCAL)
         rateSelection = check_and_cast<IQosRateSelection *>(getModuleByPath(par("rateSelectionModule")));
-        assumePeerSupportsCompressedBlockAck = par("assumePeerSupportsCompressedBlockAck");
-    }
 }
 
 simtime_t RecipientQosAckPolicy::computeBlockAckDuration(Packet *packet, const Ptr<const Ieee80211BlockAckReq>& blockAckReq) const
@@ -70,17 +68,16 @@ bool RecipientQosAckPolicy::isBlockAckNeeded(const Ptr<const Ieee80211BlockAckRe
         // frame have been discarded from the transmit buffer due to expiry of their lifetime limit.
     }
     else if (auto compressedBlockAckReq = dynamicPtrCast<const Ieee80211CompressedBlockAckReq>(blockAckReq))
-        return isCompressedBlockAckNeeded(compressedBlockAckReq, agreement, assumePeerSupportsCompressedBlockAck);
+        return isCompressedBlockAckNeeded(compressedBlockAckReq, agreement);
     else
         throw cRuntimeError("Unsupported BlockAckReq");
 }
 
-bool RecipientQosAckPolicy::isCompressedBlockAckNeeded(const Ptr<const Ieee80211CompressedBlockAckReq>& blockAckReq, RecipientBlockAckAgreement *agreement, bool assumePeerSupportsCompressedBlockAck)
+bool RecipientQosAckPolicy::isCompressedBlockAckNeeded(const Ptr<const Ieee80211CompressedBlockAckReq>& blockAckReq, RecipientBlockAckAgreement *agreement)
 {
-    // IEEE Std 802.11-2024, 9.3.1.7.2 and 10.25.6.5. Both endpoint policies
-    // must carry the explicit peer-capability assumption because this baseline
-    // does not model negotiated peer HT capability.
-    if (!assumePeerSupportsCompressedBlockAck || blockAckReq->getFragmentNumber() != 0)
+    // IEEE Std 802.11-2024, 9.3.1.7.2 and 10.25.6.5: an addressed, syntactically
+    // valid Compressed BlockAckReq elicits a Compressed BlockAck, including a null response.
+    if (blockAckReq->getFragmentNumber() != 0)
         return false;
     // A missing partial state still elicits the mandatory null compressed BA.
     return agreement == nullptr || (agreement->getIsAddbaResponseSent() && !agreement->getIsDelayedBlockAckPolicySupported());

src/inet/linklayer/ieee80211/mac/recipient/RecipientQosAckPolicy.h

@@ -20,13 +20,12 @@ class INET_API RecipientQosAckPolicy : public ModeSetListener, public IRecipient
 {
   protected:
     IQosRateSelection *rateSelection = nullptr;
-    bool assumePeerSupportsCompressedBlockAck = false;
 
   protected:
     virtual int numInitStages() const override { return NUM_INIT_STAGES; }
     virtual void initialize(int stage) override;
 
-    static bool isCompressedBlockAckNeeded(const Ptr<const Ieee80211CompressedBlockAckReq>& blockAckReq, RecipientBlockAckAgreement *agreement, bool assumePeerSupportsCompressedBlockAck);
+    static bool isCompressedBlockAckNeeded(const Ptr<const Ieee80211CompressedBlockAckReq>& blockAckReq, RecipientBlockAckAgreement *agreement);
     simtime_t computeBlockAckDuration(Packet *packet, const Ptr<const Ieee80211BlockAckReq>& blockAckReq) const;
     simtime_t computeAckDuration(Packet *packet, const Ptr<const Ieee80211DataOrMgmtHeader>& dataOrMgmtHeader) const;
 

src/inet/linklayer/ieee80211/mac/recipient/RecipientQosAckPolicy.ned

@@ -18,8 +18,5 @@ simple RecipientQosAckPolicy extends SimpleModule like IRecipientQosAckPolicy
     parameters:
         @class(RecipientQosAckPolicy);
         string rateSelectionModule;
-        // Set only for an HT-or-later local STA when peer capability management establishes that the peer supports Compressed Block Ack.
-        // This explicit assumption is needed because peer HT capabilities are not represented by the baseline agreement contract.
-        bool assumePeerSupportsCompressedBlockAck = default(false);
         @display("i=block/control");
 }

tests/module/Ieee80211CompressedBlockAckRuntime.test

@@ -22,9 +22,9 @@ abstract = false
 sim-time-limit = 1.05s
 
 **.opMode = "n(mixed-2.4Ghz)"
-# Baseline capability management is absent, so both endpoint policies explicitly
-# opt in to compressed Block Ack; the production default remains false.
-**.assumePeerSupportsCompressedBlockAck = true
+# The originator explicitly opts in based on its peer-capability assumption;
+# the recipient requires no additional station-wide capability setting.
+**.originatorAckPolicy.assumePeerSupportsCompressedBlockAck = true
 **.cmdenv-log-level = info
 
 %contains: stdout

tests/unit/Ieee80211CompressedBlockAck_1.test

@@ -43,9 +43,9 @@ class TestOriginatorQosAckPolicy : public OriginatorQosAckPolicy
 class TestRecipientQosAckPolicy : public RecipientQosAckPolicy
 {
   public:
-    static bool isCompressedResponseNeeded(const Ptr<const Ieee80211CompressedBlockAckReq>& request, RecipientBlockAckAgreement *agreement, bool enabled)
+    static bool isCompressedResponseNeeded(const Ptr<const Ieee80211CompressedBlockAckReq>& request, RecipientBlockAckAgreement *agreement)
     {
-        return isCompressedBlockAckNeeded(request, agreement, enabled);
+        return isCompressedBlockAckNeeded(request, agreement);
     }
 };
 
@@ -235,18 +235,18 @@ static Packet *makeOutstandingQosFrame(MacAddress receiverAddress, Tid tid, Frag
 
 {
     auto request = makeCompressedBlockAckReq();
-    ASSERT(!TestRecipientQosAckPolicy::isCompressedResponseNeeded(request, nullptr, false));
-    ASSERT(TestRecipientQosAckPolicy::isCompressedResponseNeeded(request, nullptr, true));
+    ASSERT(TestRecipientQosAckPolicy::isCompressedResponseNeeded(request, nullptr));
     request->setFragmentNumber(1);
-    ASSERT(!TestRecipientQosAckPolicy::isCompressedResponseNeeded(request, nullptr, true));
+    ASSERT(!TestRecipientQosAckPolicy::isCompressedResponseNeeded(request, nullptr));
     request->setFragmentNumber(0);
     RecipientBlockAckAgreement delayedAgreement(MacAddress("11:22:33:44:55:66"), 5, SequenceNumberCyclic(100), 64, SIMTIME_ZERO);
+    ASSERT(!TestRecipientQosAckPolicy::isCompressedResponseNeeded(request, &delayedAgreement));
     delayedAgreement.addbaResposneSent();
     delayedAgreement.setIsDelayedBlockAckPolicySupported(true);
-    ASSERT(!TestRecipientQosAckPolicy::isCompressedResponseNeeded(request, &delayedAgreement, true));
+    ASSERT(!TestRecipientQosAckPolicy::isCompressedResponseNeeded(request, &delayedAgreement));
     delayedAgreement.setIsDelayedBlockAckPolicySupported(false);
-    ASSERT(TestRecipientQosAckPolicy::isCompressedResponseNeeded(request, &delayedAgreement, true));
-    EV << "Recipient capability, fragment, and agreement-policy gates passed.\n";
+    ASSERT(TestRecipientQosAckPolicy::isCompressedResponseNeeded(request, &delayedAgreement));
+    EV << "Recipient fragment and agreement-policy gates passed.\n";
 }
 
 {
@@ -346,7 +346,7 @@ Established agreement produces the expected 64-bit bitmap.
 Compressed bitmap preserves leading receive-window holes.
 Compressed bitmap wraps from sequence 4095 to 0.
 Compressed bitmap preserves leading holes across sequence wrap.
-Recipient capability, fragment, and agreement-policy gates passed.
+Recipient fragment and agreement-policy gates passed.
 Originator capability, agreement, and fragmentation gates passed.
 Legacy Basic BAR and BA remain byte-exact.
 Accepted delayed agreement is retained for Basic BAR fallback.