[csl] add Mac::Frame methods to process the CSL IE (openthread#10651)

This commit provides unified methods for checking whether the CSL IE
is present and getting the CSL IE.

src/core/mac/data_poll_sender.cpp

@@ -255,16 +255,14 @@ void DataPollSender::HandlePollSent(Mac::TxFrame &aFrame, Error aError)
 
 #if OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE
         LogInfo("Failed to send data poll, error:%s, retx:%d/%d", ErrorToString(aError), mPollTxFailureCounter,
-                (aFrame.GetHeaderIe(Mac::CslIe::kHeaderIeId) != nullptr) ? kMaxCslPollRetxAttempts
-                                                                         : kMaxPollRetxAttempts);
+                aFrame.HasCslIe() ? kMaxCslPollRetxAttempts : kMaxPollRetxAttempts);
 #else
         LogInfo("Failed to send data poll, error:%s, retx:%d/%d", ErrorToString(aError), mPollTxFailureCounter,
                 kMaxPollRetxAttempts);
 #endif
 
 #if OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE
-        if (mPollTxFailureCounter <
-            ((aFrame.GetHeaderIe(Mac::CslIe::kHeaderIeId) != nullptr) ? kMaxCslPollRetxAttempts : kMaxPollRetxAttempts))
+        if (mPollTxFailureCounter < (aFrame.HasCslIe() ? kMaxCslPollRetxAttempts : kMaxPollRetxAttempts))
 #else
         if (mPollTxFailureCounter < kMaxPollRetxAttempts)
 #endif
@@ -344,7 +342,7 @@ void DataPollSender::ProcessTxDone(const Mac::TxFrame &aFrame, const Mac::RxFram
     VerifyOrExit(aFrame.GetSecurityEnabled());
 
 #if OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE
-    if (aFrame.mInfo.mTxInfo.mIsARetx && (aFrame.GetHeaderIe(Mac::CslIe::kHeaderIeId) != nullptr))
+    if (aFrame.mInfo.mTxInfo.mIsARetx && aFrame.HasCslIe())
     {
         // For retransmission frame, use a data poll to resync its parent with correct CSL phase
         sendDataPoll = true;
@@ -583,7 +581,7 @@ Mac::TxFrame *DataPollSender::PrepareDataRequest(Mac::TxFrames &aTxFrames)
                                            Mac::Frame::kSecurityEncMic32, Mac::Frame::kKeyIdMode1, nullptr);
 
 #if OPENTHREAD_CONFIG_MAC_HEADER_IE_SUPPORT && OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE
-    if (frame->GetHeaderIe(Mac::CslIe::kHeaderIeId) != nullptr)
+    if (frame->HasCslIe())
     {
         // Disable frame retransmission when the data poll has CSL IE included
         aTxFrames.SetMaxFrameRetries(0);

src/core/mac/mac.cpp

@@ -1316,7 +1316,7 @@ void Mac::HandleTransmitDone(TxFrame &aFrame, RxFrame *aAckFrame, Error aError)
                 ProcessCsl(*aAckFrame, dstAddr);
 #endif
 #if OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE
-                if (!mRxOnWhenIdle && aFrame.GetHeaderIe(CslIe::kHeaderIeId) != nullptr)
+                if (!mRxOnWhenIdle && aFrame.HasCslIe())
                 {
                     Get<DataPollSender>().ResetKeepAliveTimer();
                 }
@@ -2356,19 +2356,17 @@ bool Mac::IsCslSupported(void) const
 #if OPENTHREAD_FTD && OPENTHREAD_CONFIG_MAC_CSL_TRANSMITTER_ENABLE
 void Mac::ProcessCsl(const RxFrame &aFrame, const Address &aSrcAddr)
 {
-    const uint8_t *cur;
-    Child         *child;
-    const CslIe   *csl;
+    Child       *child;
+    const CslIe *csl;
 
     VerifyOrExit(aFrame.IsVersion2015() && aFrame.GetSecurityEnabled());
 
-    cur = aFrame.GetHeaderIe(CslIe::kHeaderIeId);
-    VerifyOrExit(cur != nullptr);
+    csl = aFrame.GetCslIe();
+    VerifyOrExit(csl != nullptr);
 
     child = Get<ChildTable>().FindChild(aSrcAddr, Child::kInStateAnyExceptInvalid);
     VerifyOrExit(child != nullptr);
 
-    csl = reinterpret_cast<const CslIe *>(cur + sizeof(HeaderIe));
     VerifyOrExit(csl->GetPeriod() >= kMinCslIePeriod);
 
     child->SetCslPeriod(csl->GetPeriod());

src/core/mac/mac_frame.cpp

@@ -1232,19 +1232,34 @@ const uint8_t *Frame::GetThreadIe(uint8_t aSubType) const
 #if OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE
 void Frame::SetCslIe(uint16_t aCslPeriod, uint16_t aCslPhase)
 {
-    uint8_t *cur = GetHeaderIe(CslIe::kHeaderIeId);
-    CslIe   *csl;
+    CslIe *csl = GetCslIe();
 
-    VerifyOrExit(cur != nullptr);
-
-    csl = reinterpret_cast<CslIe *>(cur + sizeof(HeaderIe));
+    VerifyOrExit(csl != nullptr);
     csl->SetPeriod(aCslPeriod);
     csl->SetPhase(aCslPhase);
+
 exit:
     return;
 }
+
+bool Frame::HasCslIe(void) const { return GetHeaderIe(CslIe::kHeaderIeId) != nullptr; }
 #endif // OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE
 
+#if OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE || (OPENTHREAD_FTD && OPENTHREAD_CONFIG_MAC_CSL_TRANSMITTER_ENABLE)
+const CslIe *Frame::GetCslIe(void) const
+{
+    const uint8_t *cur;
+    const CslIe   *csl = nullptr;
+
+    cur = GetHeaderIe(CslIe::kHeaderIeId);
+    VerifyOrExit(cur != nullptr);
+    csl = reinterpret_cast<const CslIe *>(cur + sizeof(HeaderIe));
+
+exit:
+    return csl;
+}
+#endif
+
 #if OPENTHREAD_CONFIG_MLE_LINK_METRICS_SUBJECT_ENABLE
 void Frame::SetEnhAckProbingIe(const uint8_t *aValue, uint8_t aLen)
 {

src/core/mac/mac_frame.hpp

@@ -134,6 +134,67 @@ class HeaderIe
 
 } OT_TOOL_PACKED_END;
 
+/**
+ * Implements CSL IE data structure.
+ *
+ */
+OT_TOOL_PACKED_BEGIN
+class CslIe
+{
+public:
+    static constexpr uint8_t kHeaderIeId    = 0x1a;
+    static constexpr uint8_t kIeContentSize = sizeof(uint16_t) * 2;
+
+    /**
+     * Returns the CSL Period.
+     *
+     * @returns the CSL Period.
+     *
+     */
+    uint16_t GetPeriod(void) const { return LittleEndian::HostSwap16(mPeriod); }
+
+    /**
+     * Sets the CSL Period.
+     *
+     * @param[in]  aPeriod  The CSL Period.
+     *
+     */
+    void SetPeriod(uint16_t aPeriod) { mPeriod = LittleEndian::HostSwap16(aPeriod); }
+
+    /**
+     * Returns the CSL Phase.
+     *
+     * @returns the CSL Phase.
+     *
+     */
+    uint16_t GetPhase(void) const { return LittleEndian::HostSwap16(mPhase); }
+
+    /**
+     * Sets the CSL Phase.
+     *
+     * @param[in]  aPhase  The CSL Phase.
+     *
+     */
+    void SetPhase(uint16_t aPhase) { mPhase = LittleEndian::HostSwap16(aPhase); }
+
+private:
+    uint16_t mPhase;
+    uint16_t mPeriod;
+} OT_TOOL_PACKED_END;
+
+/**
+ * Implements Termination2 IE.
+ *
+ * Is empty for template specialization.
+ *
+ */
+class Termination2Ie
+{
+public:
+    static constexpr uint8_t kHeaderIeId    = 0x7f;
+    static constexpr uint8_t kIeContentSize = 0;
+};
+
 #if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE || OPENTHREAD_CONFIG_MLE_LINK_METRICS_INITIATOR_ENABLE || \
     OPENTHREAD_CONFIG_MLE_LINK_METRICS_SUBJECT_ENABLE
 /**
@@ -1023,8 +1084,35 @@ class Frame : public otRadioFrame
      *
      */
     void SetCslIe(uint16_t aCslPeriod, uint16_t aCslPhase);
+
+    /**
+     * Indicates whether or not the frame contains CSL IE.
+     *
+     * @retval TRUE   If the frame contains CSL IE.
+     * @retval FALSE  If the frame doesn't contain CSL IE.
+     *
+     */
+    bool HasCslIe(void) const;
 #endif // OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE
 
+#if OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE || (OPENTHREAD_FTD && OPENTHREAD_CONFIG_MAC_CSL_TRANSMITTER_ENABLE)
+    /**
+     * Returns a pointer to a CSL IE.
+     *
+     * @returns A pointer to the CSL IE, `nullptr` if not found.
+     *
+     */
+    const CslIe *GetCslIe(void) const;
+
+    /**
+     * Returns a pointer to a CSL IE.
+     *
+     * @returns A pointer to the CSL IE, `nullptr` if not found.
+     *
+     */
+    CslIe *GetCslIe(void) { return AsNonConst(AsConst(this)->GetCslIe()); }
+#endif // OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE || (OPENTHREAD_FTD && OPENTHREAD_CONFIG_MAC_CSL_TRANSMITTER_ENABLE)
+
 #if OPENTHREAD_CONFIG_MLE_LINK_METRICS_SUBJECT_ENABLE
     /**
      * Finds Enhanced ACK Probing (Vendor Specific) IE and set its value.
@@ -1766,67 +1854,6 @@ class BeaconPayload
     otExtendedPanId mExtendedPanId;
 } OT_TOOL_PACKED_END;
 
-/**
- * Implements CSL IE data structure.
- *
- */
-OT_TOOL_PACKED_BEGIN
-class CslIe
-{
-public:
-    static constexpr uint8_t kHeaderIeId    = 0x1a;
-    static constexpr uint8_t kIeContentSize = sizeof(uint16_t) * 2;
-
-    /**
-     * Returns the CSL Period.
-     *
-     * @returns the CSL Period.
-     *
-     */
-    uint16_t GetPeriod(void) const { return LittleEndian::HostSwap16(mPeriod); }
-
-    /**
-     * Sets the CSL Period.
-     *
-     * @param[in]  aPeriod  The CSL Period.
-     *
-     */
-    void SetPeriod(uint16_t aPeriod) { mPeriod = LittleEndian::HostSwap16(aPeriod); }
-
-    /**
-     * Returns the CSL Phase.
-     *
-     * @returns the CSL Phase.
-     *
-     */
-    uint16_t GetPhase(void) const { return LittleEndian::HostSwap16(mPhase); }
-
-    /**
-     * Sets the CSL Phase.
-     *
-     * @param[in]  aPhase  The CSL Phase.
-     *
-     */
-    void SetPhase(uint16_t aPhase) { mPhase = LittleEndian::HostSwap16(aPhase); }
-
-private:
-    uint16_t mPhase;
-    uint16_t mPeriod;
-} OT_TOOL_PACKED_END;
-
-/**
- * Implements Termination2 IE.
- *
- * Is empty for template specialization.
- *
- */
-class Termination2Ie
-{
-public:
-    static constexpr uint8_t kHeaderIeId    = 0x7f;
-    static constexpr uint8_t kIeContentSize = 0;
-};
-
 /**
  * @}
  *

src/core/mac/sub_mac_csl_receiver.cpp

@@ -60,7 +60,7 @@ void SubMac::UpdateCslLastSyncTimestamp(TxFrame &aFrame, RxFrame *aAckFrame)
 {
     // Actual synchronization timestamp should be from the sent frame instead of the current time.
     // Assuming the error here since it is bounded and has very small effect on the final window duration.
-    if (aAckFrame != nullptr && aFrame.GetHeaderIe(CslIe::kHeaderIeId) != nullptr)
+    if (aAckFrame != nullptr && aFrame.HasCslIe())
     {
         mCslLastSync = TimeMicro(GetLocalTime());
     }

src/core/thread/mesh_forwarder.cpp

@@ -1138,7 +1138,7 @@ Neighbor *MeshForwarder::UpdateNeighborOnSentFrame(Mac::TxFrame       &aFrame,
 #endif // OPENTHREAD_CONFIG_RADIO_LINK_TREL_ENABLE
 
 #if OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE
-    if ((aFrame.GetHeaderIe(Mac::CslIe::kHeaderIeId) != nullptr) && aIsDataPoll)
+    if (aFrame.HasCslIe() && aIsDataPoll)
     {
         failLimit = kFailedCslDataPollTransmissions;
     }