[radio] process tx AES without otInstance (#4318)

`otPlatRadioFrameUpdated()` is declared not to access any state within
OpenThread. However, the current implementation does read the extended
address. This commit moves the AES process into `Mac::TxFrame`, which
is free of `otInstance` and eliminates the current deep callback
stacks when the radio driver wants to process tx AES from interrupt
context.

examples/platforms/nrf528xx/src/radio.c

@@ -42,6 +42,7 @@
 #include <string.h>
 
 #include "utils/code_utils.h"
+#include "utils/mac_frame.h"
 
 #include <platform-config.h>
 #include <openthread/platform/alarm-micro.h>
@@ -84,6 +85,7 @@ enum
 
 static bool sDisabled;
 
+static otExtAddress sExtAddress;
 static otError      sReceiveError = OT_ERROR_NONE;
 static otRadioFrame sReceivedFrames[NRF_802154_RX_BUFFERS];
 static otRadioFrame sTransmitFrame;
@@ -221,6 +223,11 @@ void otPlatRadioSetExtendedAddress(otInstance *aInstance, const otExtAddress *aE
 {
     OT_UNUSED_VARIABLE(aInstance);
 
+    for (size_t i = 0; i < sizeof(*aExtAddress); i++)
+    {
+        sExtAddress.m8[i] = aExtAddress->m8[sizeof(*aExtAddress) - 1 - i];
+    }
+
     nrf_802154_extended_address_set(aExtAddress->m8);
 }
 
@@ -921,7 +928,7 @@ void nrf_802154_tx_started(const uint8_t *aFrame)
 
     if (notifyFrameUpdated)
     {
-        otPlatRadioFrameUpdated(sInstance, &sTransmitFrame);
+        otMacFrameProcessTransmitAesCcm(&sTransmitFrame, &sExtAddress);
     }
 }
 #endif

examples/platforms/posix/radio.c

@@ -545,7 +545,7 @@ void radioSendMessage(otInstance *aInstance)
 
     if (notifyFrameUpdated)
     {
-        otPlatRadioFrameUpdated(aInstance, &sTransmitFrame);
+        otMacFrameProcessTransmitAesCcm(&sTransmitFrame, &sExtAddress);
     }
 #endif // OPENTHREAD_CONFIG_MAC_HEADER_IE_SUPPORT
 

examples/platforms/utils/mac_frame.cpp

@@ -115,3 +115,8 @@ uint8_t otMacFrameGetSequence(const otRadioFrame *aFrame)
 {
     return static_cast<const Mac::Frame *>(aFrame)->GetSequence();
 }
+
+void otMacFrameProcessTransmitAesCcm(otRadioFrame *aFrame, const otExtAddress *aExtAddress)
+{
+    static_cast<Mac::TxFrame *>(aFrame)->ProcessTransmitAesCcm(*static_cast<const Mac::ExtAddress *>(aExtAddress));
+}

examples/platforms/utils/mac_frame.h

@@ -140,6 +140,16 @@ otError otMacFrameGetSrcAddr(const otRadioFrame *aFrame, otMacAddress *aMacAddre
  */
 uint8_t otMacFrameGetSequence(const otRadioFrame *aFrame);
 
+/**
+ * This function performs AES CCM on the frame which is going to be sent.
+ *
+ * @param[in]  aFrame       A pointer to the MAC frame buffer that is going to be sent.
+ * @param[in]  aExtAddress  A pointer to the extended address, which will be used to generate nonce
+ *                          for AES CCM computation.
+ *
+ */
+void otMacFrameProcessTransmitAesCcm(otRadioFrame *aFrame, const otExtAddress *aExtAddress);
+
 #ifdef __cplusplus
 } // extern "C"
 #endif

include/openthread/platform/radio.h

@@ -610,21 +610,6 @@ extern void otPlatRadioTxDone(otInstance *aInstance, otRadioFrame *aFrame, otRad
  */
 extern void otPlatDiagRadioTransmitDone(otInstance *aInstance, otRadioFrame *aFrame, otError aError);
 
-/**
- * The radio driver calls this method to notify OpenThread to process transmit security for the frame,
- * this happens when the frame includes Header IE(s) that were updated before transmission.
- *
- * This function is used when feature `OPENTHREAD_CONFIG_MAC_HEADER_IE_SUPPORT` is enabled.
- *
- * @note This function can be called from interrupt context and it would only read/write data passed in
- *       via @p aFrame, but would not read/write any state within OpenThread.
- *
- * @param[in]  aInstance   The OpenThread instance structure.
- * @param[in]  aFrame      The radio frame which needs to process transmit security.
- *
- */
-extern void otPlatRadioFrameUpdated(otInstance *aInstance, otRadioFrame *aFrame);
-
 /**
  * Get the most recent RSSI measurement.
  *

src/core/mac/mac.cpp

@@ -879,31 +879,6 @@ bool Mac::IsJoinable(void) const
     return (numUnsecurePorts != 0);
 }
 
-void Mac::ProcessTransmitAesCcm(TxFrame &aFrame, const ExtAddress *aExtAddress)
-{
-    uint32_t       frameCounter = 0;
-    uint8_t        securityLevel;
-    uint8_t        nonce[KeyManager::kNonceSize];
-    uint8_t        tagLength;
-    Crypto::AesCcm aesCcm;
-    otError        error;
-
-    aFrame.GetSecurityLevel(securityLevel);
-    aFrame.GetFrameCounter(frameCounter);
-
-    KeyManager::GenerateNonce(*aExtAddress, frameCounter, securityLevel, nonce);
-
-    aesCcm.SetKey(aFrame.GetAesKey(), 16);
-    tagLength = aFrame.GetFooterLength() - Frame::kFcsSize;
-
-    error = aesCcm.Init(aFrame.GetHeaderLength(), aFrame.GetPayloadLength(), tagLength, nonce, sizeof(nonce));
-    assert(error == OT_ERROR_NONE);
-
-    aesCcm.Header(aFrame.GetHeader(), aFrame.GetHeaderLength());
-    aesCcm.Payload(aFrame.GetPayload(), aFrame.GetPayload(), aFrame.GetPayloadLength(), true);
-    aesCcm.Finalize(aFrame.GetFooter(), &tagLength);
-}
-
 void Mac::ProcessTransmitSecurity(TxFrame &aFrame, bool aProcessAesCcm)
 {
     KeyManager &      keyManager = Get<KeyManager>();
@@ -966,7 +941,7 @@ void Mac::ProcessTransmitSecurity(TxFrame &aFrame, bool aProcessAesCcm)
 
     if (aProcessAesCcm)
     {
-        ProcessTransmitAesCcm(aFrame, extAddress);
+        aFrame.ProcessTransmitAesCcm(*extAddress);
     }
 
 exit:

src/core/mac/mac.hpp

@@ -613,16 +613,6 @@ public:
      */
     bool IsEnabled(void) const { return mEnabled; }
 
-    /**
-     * This method performs AES CCM on the frame which is going to be sent.
-     *
-     * @param[in]  aFrame       A reference to the MAC frame buffer that is going to be sent.
-     * @param[in]  aExtAddress  A pointer to the extended address, which will be used to generate nonce
-     *                          for AES CCM computation.
-     *
-     */
-    static void ProcessTransmitAesCcm(TxFrame &aFrame, const ExtAddress *aExtAddress);
-
 private:
     enum
     {

src/core/mac/mac_frame.cpp

@@ -37,6 +37,8 @@
 
 #include "common/code_utils.hpp"
 #include "common/debug.hpp"
+#include "crypto/aes_ccm.hpp"
+#include "thread/key_manager.hpp"
 
 namespace ot {
 namespace Mac {
@@ -998,6 +1000,40 @@ void TxFrame::CopyFrom(const TxFrame &aFromFrame)
 #endif
 }
 
+void TxFrame::ProcessTransmitAesCcm(const ExtAddress &aExtAddress)
+{
+#if OPENTHREAD_RADIO
+    OT_UNUSED_VARIABLE(aExtAddress);
+#else
+    uint32_t       frameCounter = 0;
+    uint8_t        securityLevel;
+    uint8_t        nonce[KeyManager::kNonceSize];
+    uint8_t        tagLength;
+    Crypto::AesCcm aesCcm;
+    otError        error;
+
+    VerifyOrExit(GetSecurityEnabled());
+
+    SuccessOrExit(error = GetSecurityLevel(securityLevel));
+    SuccessOrExit(error = GetFrameCounter(frameCounter));
+
+    KeyManager::GenerateNonce(aExtAddress, frameCounter, securityLevel, nonce);
+
+    aesCcm.SetKey(GetAesKey(), 16);
+    tagLength = GetFooterLength() - Frame::kFcsSize;
+
+    error = aesCcm.Init(GetHeaderLength(), GetPayloadLength(), tagLength, nonce, sizeof(nonce));
+    assert(error == OT_ERROR_NONE);
+
+    aesCcm.Header(GetHeader(), GetHeaderLength());
+    aesCcm.Payload(GetPayload(), GetPayload(), GetPayloadLength(), true);
+    aesCcm.Finalize(GetFooter(), &tagLength);
+
+exit:
+    return;
+#endif // OPENTHREAD_MTD || OPENTHREAD_FTD
+}
+
 // LCOV_EXCL_START
 
 #if (OPENTHREAD_CONFIG_LOG_LEVEL >= OT_LOG_LEVEL_NOTE) && (OPENTHREAD_CONFIG_LOG_MAC == 1)

src/core/mac/mac_frame.hpp

@@ -1095,6 +1095,14 @@ public:
      */
     void CopyFrom(const TxFrame &aFromFrame);
 
+    /**
+     * This method performs AES CCM on the frame which is going to be sent.
+     *
+     * @param[in]  aExtAddress  A reference to the extended address, which will be used to generate nonce
+     *                          for AES CCM computation.
+     *
+     */
+    void ProcessTransmitAesCcm(const ExtAddress &aExtAddress);
 #if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE
     /**
      * This method sets the Time IE offset.

src/core/mac/sub_mac.cpp

@@ -558,13 +558,6 @@ exit:
     return swEnergyScan;
 }
 
-#if OPENTHREAD_CONFIG_MAC_HEADER_IE_SUPPORT
-void SubMac::HandleFrameUpdated(TxFrame &aFrame)
-{
-    mCallbacks.FrameUpdated(aFrame);
-}
-#endif
-
 void SubMac::SetState(State aState)
 {
     if (mState != aState)

src/core/mac/sub_mac.hpp

@@ -167,20 +167,6 @@ public:
          *
          */
         void EnergyScanDone(int8_t aMaxRssi);
-
-#if OPENTHREAD_CONFIG_MAC_HEADER_IE_SUPPORT
-        /**
-         * The method notifies user of `SubMac` to process transmit security for the frame, which  happens when the
-         * frame includes Header IE(s) that were updated before transmission.
-         *
-         * @note This function can be called from interrupt context and it would only read/write data passed in
-         *       via @p aFrame, but would not read/write any state within OpenThread.
-         *
-         * @param[in]  aFrame      The frame which needs to process transmit security.
-         *
-         */
-        void FrameUpdated(TxFrame &aFrame);
-#endif
     };
 
     /**
@@ -393,9 +379,6 @@ private:
     void HandleTransmitStarted(TxFrame &aFrame);
     void HandleTransmitDone(TxFrame &aTxFrame, RxFrame *aAckFrame, otError aError);
     void HandleEnergyScanDone(int8_t aMaxRssi);
-#if OPENTHREAD_CONFIG_MAC_HEADER_IE_SUPPORT
-    void HandleFrameUpdated(TxFrame &aFrame);
-#endif
 
     static void HandleTimer(Timer &aTimer);
     void        HandleTimer(void);

src/core/mac/sub_mac_callbacks.cpp

@@ -104,22 +104,6 @@ void SubMac::Callbacks::EnergyScanDone(int8_t aMaxRssi)
     }
 }
 
-#if OPENTHREAD_CONFIG_MAC_HEADER_IE_SUPPORT
-void SubMac::Callbacks::FrameUpdated(TxFrame &aFrame)
-{
-    /**
-     * This function will be called from interrupt context, it should only read/write data passed in
-     * via @p aFrame, but should not read/write any state within OpenThread.
-     *
-     */
-
-    if (aFrame.GetSecurityEnabled())
-    {
-        Get<Mac>().ProcessTransmitAesCcm(aFrame, &Get<Mac>().GetExtAddress());
-    }
-}
-#endif
-
 #elif OPENTHREAD_RADIO
 
 void SubMac::Callbacks::ReceiveDone(RxFrame *aFrame, otError aError)
@@ -150,19 +134,6 @@ void SubMac::Callbacks::EnergyScanDone(int8_t aMaxRssi)
     Get<LinkRaw>().InvokeEnergyScanDone(aMaxRssi);
 }
 
-#if OPENTHREAD_CONFIG_MAC_HEADER_IE_SUPPORT
-void SubMac::Callbacks::FrameUpdated(TxFrame &)
-{
-    /**
-     * This function will be called from interrupt context, it should only read/write data passed in
-     * via @p aFrame, but should not read/write any state within OpenThread.
-     *
-     */
-
-    // For now this functionality is not supported in Radio Only mode.
-}
-#endif
-
 #endif // OPENTHREAD_RADIO
 
 } // namespace Mac

src/core/radio/radio.hpp

@@ -147,22 +147,6 @@ public:
          */
         void HandleEnergyScanDone(int8_t aMaxRssi);
 
-#if OPENTHREAD_CONFIG_MAC_HEADER_IE_SUPPORT
-        /**
-         * This callback method handles a "Frame Updated" event from radio platform.
-         *
-         * This is called to notify OpenThread to process transmit security for the frame, this happens when the frame
-         * includes Header IE(s) that were updated before transmission. It is called from `otPlatRadioFrameUpdated()`.
-         *
-         * @note This method can be called from interrupt context and it would only read/write data passed in
-         *       via @p aFrame, but would not read/write any state within OpenThread.
-         *
-         * @param[in]  aFrame      The frame which needs to process transmit security.
-         *
-         */
-        void HandleFrameUpdated(Mac::TxFrame &aFrame);
-#endif
-
 #if OPENTHREAD_CONFIG_DIAG_ENABLE
         /**
          * This callback method handles a "Receive Done" event from radio platform when diagnostics mode is enabled.

src/core/radio/radio_callbacks.cpp

@@ -58,13 +58,6 @@ void Radio::Callbacks::HandleEnergyScanDone(int8_t aMaxRssi)
     Get<Mac::SubMac>().HandleEnergyScanDone(aMaxRssi);
 }
 
-#if OPENTHREAD_CONFIG_MAC_HEADER_IE_SUPPORT
-void Radio::Callbacks::HandleFrameUpdated(Mac::TxFrame &aFrame)
-{
-    Get<Mac::SubMac>().HandleFrameUpdated(aFrame);
-}
-#endif
-
 #if OPENTHREAD_CONFIG_DIAG_ENABLE
 void Radio::Callbacks::HandleDiagsReceiveDone(Mac::RxFrame *aFrame, otError aError)
 {

src/core/radio/radio_platform.cpp

@@ -81,18 +81,6 @@ extern "C" void otPlatRadioEnergyScanDone(otInstance *aInstance, int8_t aEnergyS
     }
 }
 
-#if OPENTHREAD_CONFIG_MAC_HEADER_IE_SUPPORT
-extern "C" void otPlatRadioFrameUpdated(otInstance *aInstance, otRadioFrame *aFrame)
-{
-    Instance *instance = static_cast<Instance *>(aInstance);
-
-    if (instance->IsInitialized())
-    {
-        instance->Get<Radio::Callbacks>().HandleFrameUpdated(*static_cast<Mac::TxFrame *>(aFrame));
-    }
-}
-#endif
-
 #if OPENTHREAD_CONFIG_DIAG_ENABLE
 extern "C" void otPlatDiagRadioReceiveDone(otInstance *aInstance, otRadioFrame *aFrame, otError aError)
 {