Require radio driver to provide transmit and receive buffers. (#87)

Some radio chips have memory-mapped regions for transmit and receive buffers.
This change allows the radio driver to pass those buffers, when available,
directly to upper layers and avoid unnecessary copies.

examples/platform/posix/radio.cpp

@@ -65,19 +65,22 @@ enum PhyState
 struct RadioMessage
 {
     uint8_t mChannel;
-    uint8_t mPsdu[Mac::Frame::kMTU];
+    uint8_t mPsdu[kMaxPHYPacketSize];
 } __attribute__((packed));
 
 static void radioSendAck(void);
 static void radioProcessFrame(void);
 
 static PhyState s_state = kStateDisabled;
-static RadioPacket *s_receive_frame = NULL;
-static RadioPacket *s_transmit_frame = NULL;
-static RadioPacket m_ack_packet;
+static RadioMessage s_receive_message;
+static RadioMessage s_transmit_message;
+static RadioMessage s_ack_message;
+static RadioPacket s_receive_frame;
+static RadioPacket s_transmit_frame;
+static RadioPacket s_ack_frame;
 static bool s_data_pending = false;
 
-static uint8_t s_extended_address[8];
+static uint8_t s_extended_address[OT_EXT_ADDRESS_SIZE];
 static uint16_t s_short_address;
 static uint16_t s_panid;
 
@@ -93,7 +96,7 @@ ThreadError otPlatRadioSetExtendedAddress(uint8_t *address)
 {
     for (unsigned i = 0; i < sizeof(s_extended_address); i++)
     {
-        s_extended_address[i] = address[7 - i];
+        s_extended_address[i] = address[sizeof(s_extended_address) - 1 - i];
     }
 
     return kThreadError_None;
@@ -115,6 +118,10 @@ void PlatformRadioInit(void)
 
     s_sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
     bind(s_sockfd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
+
+    s_receive_frame.mPsdu = s_receive_message.mPsdu;
+    s_transmit_frame.mPsdu = s_transmit_message.mPsdu;
+    s_ack_frame.mPsdu = s_ack_message.mPsdu;
 }
 
 ThreadError otPlatRadioEnable(void)
@@ -173,25 +180,29 @@ exit:
     return error;
 }
 
-ThreadError otPlatRadioReceive(RadioPacket *packet)
+ThreadError otPlatRadioReceive(uint8_t aChannel)
 {
     ThreadError error = kThreadError_None;
 
     VerifyOrExit(s_state == kStateIdle, error = kThreadError_Busy);
     s_state = kStateListen;
-    s_receive_frame = packet;
+    s_receive_frame.mChannel = aChannel;
 
 exit:
     return error;
 }
 
-ThreadError otPlatRadioTransmit(RadioPacket *packet)
+RadioPacket *otPlatRadioGetTransmitBuffer(void)
+{
+    return &s_transmit_frame;
+}
+
+ThreadError otPlatRadioTransmit(void)
 {
     ThreadError error = kThreadError_None;
 
     VerifyOrExit(s_state == kStateIdle, error = kThreadError_Busy);
     s_state = kStateTransmit;
-    s_transmit_frame = packet;
     s_data_pending = false;
 
 exit:
@@ -227,8 +238,6 @@ exit:
 
 void radioReceive(void)
 {
-    RadioPacket receive_frame;
-    RadioMessage message;
     uint8_t tx_sequence, rx_sequence;
     uint8_t command_id;
     int rval;
@@ -236,7 +245,7 @@ void radioReceive(void)
     VerifyOrExit(s_state == kStateDisabled || s_state == kStateSleep || s_state == kStateListen ||
                  s_state == kStateAckWait, ;);
 
-    rval = recvfrom(s_sockfd, &message, sizeof(message), 0, NULL, NULL);
+    rval = recvfrom(s_sockfd, &s_receive_message, sizeof(s_receive_message), 0, NULL, NULL);
     assert(rval >= 0);
 
     switch (s_state)
@@ -248,25 +257,24 @@ void radioReceive(void)
         break;
 
     case kStateAckWait:
-        receive_frame.mLength = rval - 1;
-        memcpy(receive_frame.mPsdu, message.mPsdu, receive_frame.mLength);
+        s_receive_frame.mLength = rval - 1;
 
-        if (reinterpret_cast<Mac::Frame *>(&receive_frame)->GetType() != Mac::Frame::kFcfFrameAck)
+        if (reinterpret_cast<Mac::Frame *>(&s_receive_frame)->GetType() != Mac::Frame::kFcfFrameAck)
         {
             break;
         }
 
-        tx_sequence = reinterpret_cast<Mac::Frame *>(s_transmit_frame)->GetSequence();
-        rx_sequence = reinterpret_cast<Mac::Frame *>(&receive_frame)->GetSequence();
+        tx_sequence = reinterpret_cast<Mac::Frame *>(&s_transmit_frame)->GetSequence();
+        rx_sequence = reinterpret_cast<Mac::Frame *>(&s_receive_frame)->GetSequence();
 
         if (tx_sequence != rx_sequence)
         {
             break;
         }
 
-        if (reinterpret_cast<Mac::Frame *>(s_transmit_frame)->GetType() == Mac::Frame::kFcfFrameMacCmd)
+        if (reinterpret_cast<Mac::Frame *>(&s_transmit_frame)->GetType() == Mac::Frame::kFcfFrameMacCmd)
         {
-            reinterpret_cast<Mac::Frame *>(s_transmit_frame)->GetCommandId(command_id);
+            reinterpret_cast<Mac::Frame *>(&s_transmit_frame)->GetCommandId(command_id);
 
             if (command_id == Mac::Frame::kMacCmdDataRequest)
             {
@@ -279,14 +287,13 @@ void radioReceive(void)
         break;
 
     case kStateListen:
-        if (s_receive_frame->mChannel != message.mChannel)
+        if (s_receive_frame.mChannel != s_receive_message.mChannel)
         {
             break;
         }
 
         s_state = kStateReceive;
-        s_receive_frame->mLength = rval - 1;
-        memcpy(s_receive_frame->mPsdu, message.mPsdu, s_receive_frame->mLength);
+        s_receive_frame.mLength = rval - 1;
 
         radioProcessFrame();
         break;
@@ -303,15 +310,13 @@ exit:
 int radioTransmit(void)
 {
     struct sockaddr_in sockaddr;
-    RadioMessage message;
     int rval = 0;
 
     memset(&sockaddr, 0, sizeof(sockaddr));
     sockaddr.sin_family = AF_INET;
     inet_pton(AF_INET, "127.0.0.1", &sockaddr.sin_addr);
 
-    message.mChannel = s_transmit_frame->mChannel;
-    memcpy(message.mPsdu, s_transmit_frame->mPsdu, s_transmit_frame->mLength);
+    s_transmit_message.mChannel = s_transmit_frame.mChannel;
 
     for (unsigned i = 1; i < 34; i++)
     {
@@ -321,12 +326,12 @@ int radioTransmit(void)
         }
 
         sockaddr.sin_port = htons(9000 + i);
-        rval = sendto(s_sockfd, &message, 1 + s_transmit_frame->mLength, 0, (struct sockaddr *)&sockaddr,
+        rval = sendto(s_sockfd, &s_transmit_message, 1 + s_transmit_frame.mLength, 0, (struct sockaddr *)&sockaddr,
                       sizeof(sockaddr));
         assert(rval >= 0);
     }
 
-    if (reinterpret_cast<Mac::Frame *>(s_transmit_frame)->GetAckRequest())
+    if (reinterpret_cast<Mac::Frame *>(&s_transmit_frame)->GetAckRequest())
     {
         s_state = kStateAckWait;
     }
@@ -382,13 +387,12 @@ void PlatformRadioProcess(void)
 void radioSendAck(void)
 {
     Mac::Frame *ack_frame;
-    RadioMessage message;
     uint8_t sequence;
     struct sockaddr_in sockaddr;
 
-    sequence = reinterpret_cast<Mac::Frame *>(s_receive_frame)->GetSequence();
+    sequence = reinterpret_cast<Mac::Frame *>(&s_receive_frame)->GetSequence();
 
-    ack_frame = reinterpret_cast<Mac::Frame *>(&m_ack_packet);
+    ack_frame = reinterpret_cast<Mac::Frame *>(&s_ack_frame);
     ack_frame->InitMacHeader(Mac::Frame::kFcfFrameAck, Mac::Frame::kSecNone);
     ack_frame->SetSequence(sequence);
 
@@ -396,8 +400,7 @@ void radioSendAck(void)
     sockaddr.sin_family = AF_INET;
     inet_pton(AF_INET, "127.0.0.1", &sockaddr.sin_addr);
 
-    message.mChannel = s_receive_frame->mChannel;
-    memcpy(message.mPsdu, m_ack_packet.mPsdu, m_ack_packet.mLength);
+    s_ack_message.mChannel = s_receive_frame.mChannel;
 
     for (unsigned i = 1; i < 34; i++)
     {
@@ -407,7 +410,7 @@ void radioSendAck(void)
         }
 
         sockaddr.sin_port = htons(9000 + i);
-        sendto(s_sockfd, &message, 1 + m_ack_packet.mLength, 0, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
+        sendto(s_sockfd, &s_ack_message, 1 + s_ack_frame.mLength, 0, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
     }
 }
 
@@ -418,7 +421,7 @@ void radioProcessFrame(void)
     uint16_t dstpan;
     Mac::Address dstaddr;
 
-    receive_frame = reinterpret_cast<Mac::Frame *>(s_receive_frame);
+    receive_frame = reinterpret_cast<Mac::Frame *>(&s_receive_frame);
     receive_frame->GetDstAddr(dstaddr);
 
     switch (dstaddr.mLength)
@@ -444,11 +447,11 @@ void radioProcessFrame(void)
         ExitNow(error = kThreadError_Abort);
     }
 
-    s_receive_frame->mPower = -20;
-    s_receive_frame->mLqi = kPhyNoLqi;
+    s_receive_frame.mPower = -20;
+    s_receive_frame.mLqi = kPhyNoLqi;
 
     // generate acknowledgment
-    if (reinterpret_cast<Mac::Frame *>(s_receive_frame)->GetAckRequest())
+    if (reinterpret_cast<Mac::Frame *>(&s_receive_frame)->GetAckRequest())
     {
         radioSendAck();
     }
@@ -460,7 +463,12 @@ exit:
         s_state = kStateIdle;
     }
 
-    otPlatRadioReceiveDone(error);
+    if (error != kThreadError_None)
+    {
+        receive_frame = NULL;
+    }
+
+    otPlatRadioReceiveDone(receive_frame, error);
 }
 
 #ifdef __cplusplus

include/platform/radio.h

@@ -95,12 +95,12 @@ typedef enum otRadioCaps
  */
 typedef struct RadioPacket
 {
-    uint8_t mLength;                   ///< Length of the PSDU.
-    uint8_t mPsdu[kMaxPHYPacketSize];  ///< The PSDU.
-    uint8_t mChannel;                  ///< Channel used to transmit/receive the frame.
-    int8_t  mPower;                    ///< Transmit/receive power in dBm.
-    uint8_t mLqi;                      ///< Link Quality Indicator for received frames.
-    bool    mSecurityValid;            ///< Security Enabled flag is set and frame passes security checks.
+    uint8_t *mPsdu;          ///< The PSDU.
+    uint8_t mLength;         ///< Length of the PSDU.
+    uint8_t mChannel;        ///< Channel used to transmit/receive the frame.
+    int8_t  mPower;          ///< Transmit/receive power in dBm.
+    uint8_t mLqi;            ///< Link Quality Indicator for received frames.
+    bool    mSecurityValid;  ///< Security Enabled flag is set and frame passes security checks.
 } RadioPacket;
 
 /**
@@ -208,14 +208,12 @@ ThreadError otPlatRadioIdle(void);
  * 2. Remain in Receive until a packet is received or reception is aborted.
  * 3. Return to Idle.
  *
- * @param[in]  aPacket  A pointer to a packet buffer.
- *
- * @note The channel is specified in @p aPacket.
+ * @param[in]  aChannel  The channel to use for receiving.
  *
  * @retval ::kThreadError_None  Successfully transitioned to Receive.
  * @retval ::kThreadError_Fail  Failed to transition to Receive.
  */
-ThreadError otPlatRadioReceive(RadioPacket *aPacket);
+ThreadError otPlatRadioReceive(uint8_t aChannel);
 
 /**
  * The radio driver calls this method to notify OpenThread of a received packet.
@@ -224,26 +222,34 @@ ThreadError otPlatRadioReceive(RadioPacket *aPacket);
  *                      was aborted and a frame was not received.
  *
  */
-extern void otPlatRadioReceiveDone(ThreadError error);
+extern void otPlatRadioReceiveDone(RadioPacket *aPacket, ThreadError error);
 
 /**
- * Begins the transmit sequence on the radio.
+ * This method returns a pointer to the transmit buffer.
+ *
+ * The caller forms the IEEE 802.15.4 frame in this buffer then calls otPlatRadioTransmit() to request transmission.
+ *
+ * @returns A pointer to the transmit buffer.
+ *
+ */
+RadioPacket *otPlatRadioGetTransmitBuffer(void);
+
+/**
+ * This method begins the transmit sequence on the radio.
+ *
+ * The caller must form the IEEE 802.15.4 frame in the buffer provided by otPlatRadioGetTransmitBuffer() before requesting
+ * transmission.  The channel and transmit power are also included in the RadioPacket structure.
  *
  * The transmit sequence consists of:
  * 1. Transitioning the radio to Transmit from Idle.
  * 2. Transmits the psdu on the given channel and at the given transmit power.
  * 3. Return to Idle.
  *
- * @param[in]  aPacket  A pointer to a packet buffer.
- *
- * @note The channel is specified in @p aPacket.
- * @note The transmit power is specified in @p aPacket.
- *
  * @retval ::kThreadError_None         Successfully transitioned to Transmit.
  * @retval ::kThreadError_InvalidArgs  One or more parameters in @p aPacket are invalid.
  * @retval ::kThreadError_Fail         Failed to transition to Transmit.
  */
-ThreadError otPlatRadioTransmit(RadioPacket *aPacket);
+ThreadError otPlatRadioTransmit(void);
 
 /**
  * The radio driver calls this method to notify OpenThread that the transmission has completed.

src/cli/cli_serial.cpp

@@ -135,7 +135,7 @@ ThreadError Serial::ProcessCommand(void)
 int Serial::Output(const char *aBuf, uint16_t aBufLength)
 {
     uint16_t remaining = kTxBufferSize - mTxLength;
-    uint16_t tail = (mTxHead + mTxLength) % kTxBufferSize;
+    uint16_t tail;
 
     if (aBufLength > remaining)
     {
@@ -170,7 +170,7 @@ void Serial::Send(void)
 {
     VerifyOrExit(mSendLength == 0, ;);
 
-    if (mTxHead + mTxLength > kTxBufferSize)
+    if (mTxLength > kTxBufferSize - mTxHead)
     {
         mSendLength = kTxBufferSize - mTxHead;
     }

src/core/mac/mac.cpp

@@ -289,15 +289,13 @@ void Mac::NextOperation(void)
     switch (mState)
     {
     case kStateActiveScan:
-        mReceiveFrame.SetChannel(mScanChannel);
-        otPlatRadioReceive(&mReceiveFrame);
+        otPlatRadioReceive(mScanChannel);
         break;
 
     default:
         if (mRxOnWhenIdle || mReceiveTimer.IsRunning())
         {
-            mReceiveFrame.SetChannel(mChannel);
-            otPlatRadioReceive(&mReceiveFrame);
+            otPlatRadioReceive(mChannel);
         }
         else
         {
@@ -389,34 +387,33 @@ void Mac::HandleBeginTransmit(void *aContext)
     obj->HandleBeginTransmit();
 }
 
-void Mac::ProcessTransmitSecurity(void)
+void Mac::ProcessTransmitSecurity(Frame &aFrame)
 {
     uint8_t securityLevel;
     uint8_t nonce[kNonceSize];
     uint8_t tagLength;
     Crypto::AesCcm aesCcm;
 
-    if (mSendFrame.GetSecurityEnabled() == false)
+    if (aFrame.GetSecurityEnabled() == false)
     {
         ExitNow();
     }
 
-    mSendFrame.GetSecurityLevel(securityLevel);
-    mSendFrame.SetFrameCounter(mKeyManager.GetMacFrameCounter());
+    aFrame.GetSecurityLevel(securityLevel);
+    aFrame.SetFrameCounter(mKeyManager.GetMacFrameCounter());
 
-    mSendFrame.SetKeyId((mKeyManager.GetCurrentKeySequence() & 0x7f) + 1);
+    aFrame.SetKeyId((mKeyManager.GetCurrentKeySequence() & 0x7f) + 1);
 
     GenerateNonce(mExtAddress, mKeyManager.GetMacFrameCounter(), securityLevel, nonce);
 
     aesCcm.SetKey(mKeyManager.GetCurrentMacKey(), 16);
-    tagLength = mSendFrame.GetFooterLength() - Frame::kFcsSize;
+    tagLength = aFrame.GetFooterLength() - Frame::kFcsSize;
 
-    aesCcm.Init(mSendFrame.GetHeaderLength(), mSendFrame.GetPayloadLength(), tagLength,
-                nonce, sizeof(nonce));
+    aesCcm.Init(aFrame.GetHeaderLength(), aFrame.GetPayloadLength(), tagLength, nonce, sizeof(nonce));
 
-    aesCcm.Header(mSendFrame.GetHeader(), mSendFrame.GetHeaderLength());
-    aesCcm.Payload(mSendFrame.GetPayload(), mSendFrame.GetPayload(), mSendFrame.GetPayloadLength(), true);
-    aesCcm.Finalize(mSendFrame.GetFooter(), &tagLength);
+    aesCcm.Header(aFrame.GetHeader(), aFrame.GetHeaderLength());
+    aesCcm.Payload(aFrame.GetPayload(), aFrame.GetPayload(), aFrame.GetPayloadLength(), true);
+    aesCcm.Finalize(aFrame.GetFooter(), &tagLength);
 
     mKeyManager.IncrementMacFrameCounter();
 
@@ -426,6 +423,7 @@ exit:
 
 void Mac::HandleBeginTransmit(void)
 {
+    Frame &sendFrame(*static_cast<Frame *>(otPlatRadioGetTransmitBuffer()));
     ThreadError error = kThreadError_None;
 
     if (otPlatRadioIdle() != kThreadError_None)
@@ -437,21 +435,21 @@ void Mac::HandleBeginTransmit(void)
     switch (mState)
     {
     case kStateActiveScan:
-        mSendFrame.SetChannel(mScanChannel);
-        SendBeaconRequest(mSendFrame);
-        mSendFrame.SetSequence(0);
+        sendFrame.SetChannel(mScanChannel);
+        SendBeaconRequest(sendFrame);
+        sendFrame.SetSequence(0);
         break;
 
     case kStateTransmitBeacon:
-        mSendFrame.SetChannel(mChannel);
-        SendBeacon(mSendFrame);
-        mSendFrame.SetSequence(mBeaconSequence++);
+        sendFrame.SetChannel(mChannel);
+        SendBeacon(sendFrame);
+        sendFrame.SetSequence(mBeaconSequence++);
         break;
 
     case kStateTransmitData:
-        mSendFrame.SetChannel(mChannel);
-        SuccessOrExit(error = mSendHead->HandleFrameRequest(mSendFrame));
-        mSendFrame.SetSequence(mDataSequence);
+        sendFrame.SetChannel(mChannel);
+        SuccessOrExit(error = mSendHead->HandleFrameRequest(sendFrame));
+        sendFrame.SetSequence(mDataSequence);
         break;
 
     default:
@@ -460,11 +458,11 @@ void Mac::HandleBeginTransmit(void)
     }
 
     // Security Processing
-    ProcessTransmitSecurity();
+    ProcessTransmitSecurity(sendFrame);
 
-    SuccessOrExit(error = otPlatRadioTransmit(&mSendFrame));
+    SuccessOrExit(error = otPlatRadioTransmit());
 
-    if (mSendFrame.GetAckRequest() && !(otPlatRadioGetCaps() & kRadioCapsAckTimeout))
+    if (sendFrame.GetAckRequest() && !(otPlatRadioGetCaps() & kRadioCapsAckTimeout))
     {
         mAckTimer.Start(kAckTimeout);
         otLogDebgMac("ack timer start\n");
@@ -587,6 +585,7 @@ void Mac::HandleReceiveTimer(void)
 
 void Mac::SentFrame(bool aAcked)
 {
+    Frame &sendFrame(*static_cast<Frame *>(otPlatRadioGetTransmitBuffer()));
     Address destination;
     Neighbor *neighbor;
     Sender *sender;
@@ -602,9 +601,9 @@ void Mac::SentFrame(bool aAcked)
         break;
 
     case kStateTransmitData:
-        if (mSendFrame.GetAckRequest() && !aAcked)
+        if (sendFrame.GetAckRequest() && !aAcked)
         {
-            otDumpDebgMac("NO ACK", mSendFrame.GetHeader(), 16);
+            otDumpDebgMac("NO ACK", sendFrame.GetHeader(), 16);
 
             if (mTransmitAttempts < kMaxFrameAttempts)
             {
@@ -613,7 +612,7 @@ void Mac::SentFrame(bool aAcked)
                 ExitNow();
             }
 
-            mSendFrame.GetDstAddr(destination);
+            sendFrame.GetDstAddr(destination);
 
             if ((neighbor = mMle.GetNeighbor(destination)) != NULL)
             {
@@ -632,7 +631,7 @@ void Mac::SentFrame(bool aAcked)
         }
 
         mDataSequence++;
-        sender->HandleSentFrame(mSendFrame);
+        sender->HandleSentFrame(sendFrame);
 
         ScheduleNextTransmission();
         break;
@@ -646,7 +645,7 @@ exit:
     {}
 }
 
-ThreadError Mac::ProcessReceiveSecurity(const Address &aSrcAddr, Neighbor *aNeighbor)
+ThreadError Mac::ProcessReceiveSecurity(Frame &aFrame, const Address &aSrcAddr, Neighbor *aNeighbor)
 {
     ThreadError error = kThreadError_None;
     uint8_t securityLevel;
@@ -659,23 +658,23 @@ ThreadError Mac::ProcessReceiveSecurity(const Address &aSrcAddr, Neighbor *aNeig
     const uint8_t *macKey;
     Crypto::AesCcm aesCcm;
 
-    mReceiveFrame.SetSecurityValid(false);
+    aFrame.SetSecurityValid(false);
 
-    if (mReceiveFrame.GetSecurityEnabled() == false)
+    if (aFrame.GetSecurityEnabled() == false)
     {
         ExitNow();
     }
 
     VerifyOrExit(aNeighbor != NULL, error = kThreadError_Security);
 
-    mReceiveFrame.GetSecurityLevel(securityLevel);
-    mReceiveFrame.GetFrameCounter(frameCounter);
+    aFrame.GetSecurityLevel(securityLevel);
+    aFrame.GetFrameCounter(frameCounter);
 
     GenerateNonce(aSrcAddr.mExtAddress, frameCounter, securityLevel, nonce);
 
-    tagLength = mReceiveFrame.GetFooterLength() - Frame::kFcsSize;
+    tagLength = aFrame.GetFooterLength() - Frame::kFcsSize;
 
-    mReceiveFrame.GetKeyId(keyid);
+    aFrame.GetKeyId(keyid);
     keyid--;
 
     if (keyid == (mKeyManager.GetCurrentKeySequence() & 0x7f))
@@ -705,21 +704,19 @@ ThreadError Mac::ProcessReceiveSecurity(const Address &aSrcAddr, Neighbor *aNeig
     {
         for (Receiver *receiver = mReceiveHead; receiver; receiver = receiver->mNext)
         {
-            receiver->HandleReceivedFrame(mReceiveFrame, kThreadError_Security);
+            receiver->HandleReceivedFrame(aFrame, kThreadError_Security);
         }
 
         ExitNow(error = kThreadError_Security);
     }
 
     aesCcm.SetKey(macKey, 16);
-    aesCcm.Init(mReceiveFrame.GetHeaderLength(), mReceiveFrame.GetPayloadLength(),
-                tagLength, nonce, sizeof(nonce));
-    aesCcm.Header(mReceiveFrame.GetHeader(), mReceiveFrame.GetHeaderLength());
-    aesCcm.Payload(mReceiveFrame.GetPayload(), mReceiveFrame.GetPayload(), mReceiveFrame.GetPayloadLength(),
-                   false);
+    aesCcm.Init(aFrame.GetHeaderLength(), aFrame.GetPayloadLength(), tagLength, nonce, sizeof(nonce));
+    aesCcm.Header(aFrame.GetHeader(), aFrame.GetHeaderLength());
+    aesCcm.Payload(aFrame.GetPayload(), aFrame.GetPayload(), aFrame.GetPayloadLength(), false);
     aesCcm.Finalize(tag, &tagLength);
 
-    VerifyOrExit(memcmp(tag, mReceiveFrame.GetFooter(), tagLength) == 0, error = kThreadError_Security);
+    VerifyOrExit(memcmp(tag, aFrame.GetFooter(), tagLength) == 0, error = kThreadError_Security);
 
     if (keySequence > mKeyManager.GetCurrentKeySequence())
     {
@@ -733,18 +730,18 @@ ThreadError Mac::ProcessReceiveSecurity(const Address &aSrcAddr, Neighbor *aNeig
 
     aNeighbor->mValid.mLinkFrameCounter = frameCounter + 1;
 
-    mReceiveFrame.SetSecurityValid(true);
+    aFrame.SetSecurityValid(true);
 
 exit:
     return error;
 }
 
-extern "C" void otPlatRadioReceiveDone(ThreadError aError)
+extern "C" void otPlatRadioReceiveDone(RadioPacket *aFrame, ThreadError aError)
 {
-    sMac->ReceiveDoneTask(aError);
+    sMac->ReceiveDoneTask(static_cast<Frame *>(aFrame), aError);
 }
 
-void Mac::ReceiveDoneTask(ThreadError aError)
+void Mac::ReceiveDoneTask(Frame *aFrame, ThreadError aError)
 {
     Address srcaddr;
     Address dstaddr;
@@ -753,9 +750,9 @@ void Mac::ReceiveDoneTask(ThreadError aError)
     Whitelist::Entry *entry;
     int8_t rssi;
 
-    VerifyOrExit(aError == kThreadError_None, ;);
+    VerifyOrExit(aError == kThreadError_None && aFrame != NULL, ;);
 
-    mReceiveFrame.GetSrcAddr(srcaddr);
+    aFrame->GetSrcAddr(srcaddr);
     neighbor = mMle.GetNeighbor(srcaddr);
 
     switch (srcaddr.mLength)
@@ -783,12 +780,12 @@ void Mac::ReceiveDoneTask(ThreadError aError)
 
         if (mWhitelist.GetConstantRssi(*entry, rssi) == kThreadError_None)
         {
-            mReceiveFrame.mPower = rssi;
+            aFrame->mPower = rssi;
         }
     }
 
     // Destination Address Filtering
-    mReceiveFrame.GetDstAddr(dstaddr);
+    aFrame->GetDstAddr(dstaddr);
 
     switch (dstaddr.mLength)
     {
@@ -796,28 +793,28 @@ void Mac::ReceiveDoneTask(ThreadError aError)
         break;
 
     case sizeof(ShortAddress):
-        mReceiveFrame.GetDstPanId(panid);
+        aFrame->GetDstPanId(panid);
         VerifyOrExit((panid == kShortAddrBroadcast || panid == mPanId) &&
                      ((mRxOnWhenIdle && dstaddr.mShortAddress == kShortAddrBroadcast) ||
                       dstaddr.mShortAddress == mShortAddress), ;);
         break;
 
     case sizeof(ExtAddress):
-        mReceiveFrame.GetDstPanId(panid);
+        aFrame->GetDstPanId(panid);
         VerifyOrExit(panid == mPanId &&
                      memcmp(&dstaddr.mExtAddress, &mExtAddress, sizeof(dstaddr.mExtAddress)) == 0, ;);
         break;
     }
 
     // Security Processing
-    SuccessOrExit(ProcessReceiveSecurity(srcaddr, neighbor));
+    SuccessOrExit(ProcessReceiveSecurity(*aFrame, srcaddr, neighbor));
 
     switch (mState)
     {
     case kStateActiveScan:
-        if (mReceiveFrame.GetType() == Frame::kFcfFrameBeacon)
+        if (aFrame->GetType() == Frame::kFcfFrameBeacon)
         {
-            mActiveScanHandler(mActiveScanContext, &mReceiveFrame);
+            mActiveScanHandler(mActiveScanContext, aFrame);
         }
 
         break;
@@ -828,14 +825,14 @@ void Mac::ReceiveDoneTask(ThreadError aError)
             mReceiveTimer.Stop();
         }
 
-        if (mReceiveFrame.GetType() == Frame::kFcfFrameMacCmd)
+        if (aFrame->GetType() == Frame::kFcfFrameMacCmd)
         {
-            SuccessOrExit(HandleMacCommand());
+            SuccessOrExit(HandleMacCommand(*aFrame));
         }
 
         for (Receiver *receiver = mReceiveHead; receiver; receiver = receiver->mNext)
         {
-            receiver->HandleReceivedFrame(mReceiveFrame, kThreadError_None);
+            receiver->HandleReceivedFrame(*aFrame, kThreadError_None);
         }
 
         break;
@@ -845,11 +842,12 @@ exit:
     NextOperation();
 }
 
-ThreadError Mac::HandleMacCommand(void)
+ThreadError Mac::HandleMacCommand(Frame &aFrame)
 {
     ThreadError error = kThreadError_None;
     uint8_t commandId;
-    mReceiveFrame.GetCommandId(commandId);
+
+    aFrame.GetCommandId(commandId);
 
     if (commandId == Frame::kMacCmdBeaconRequest)
     {

src/core/mac/mac.hpp

@@ -366,11 +366,12 @@ public:
     /**
      * This method is called to handle receive events.
      *
-     * @param[in]  aError   ::kThreadError_None when successfully received a frame, ::kThreadError_Abort when reception
-     *                      was aborted and a frame was not received.
+     * @param[in]  aFrame  A pointer to the received frame, or NULL if the receive operation aborted.
+     * @param[in]  aError  ::kThreadError_None when successfully received a frame, ::kThreadError_Abort when reception
+     *                     was aborted and a frame was not received.
      *
      */
-    void ReceiveDoneTask(ThreadError aError);
+    void ReceiveDoneTask(Frame *aFrame, ThreadError aError);
 
     /**
      * This method is called to handle transmit events.
@@ -393,14 +394,14 @@ public:
 private:
     void GenerateNonce(const ExtAddress &aAddress, uint32_t aFrameCounter, uint8_t aSecurityLevel, uint8_t *aNonce);
     void NextOperation(void);
-    void ProcessTransmitSecurity(void);
-    ThreadError ProcessReceiveSecurity(const Address &aSrcAddr, Neighbor *aNeighbor);
+    void ProcessTransmitSecurity(Frame &aFrame);
+    ThreadError ProcessReceiveSecurity(Frame &aFrame, const Address &aSrcAddr, Neighbor *aNeighbor);
     void ScheduleNextTransmission(void);
     void SentFrame(bool aAcked);
     void SendBeaconRequest(Frame &aFrame);
     void SendBeacon(Frame &aFrame);
     void StartBackoff(void);
-    ThreadError HandleMacCommand(void);
+    ThreadError HandleMacCommand(Frame &aFrame);
 
     static void HandleAckTimer(void *aContext);
     void HandleAckTimer(void);
@@ -426,8 +427,6 @@ private:
 
     Beacon mBeacon;
 
-    Frame mSendFrame;
-    Frame mReceiveFrame;
     Sender *mSendHead, *mSendTail;
     Receiver *mReceiveHead, *mReceiveTail;
 

tests/unit/test_mac_frame.cpp

@@ -74,7 +74,11 @@ void TestMacHeader(void)
 
     for (unsigned i = 0; i < sizeof(tests) / sizeof(tests[0]); i++)
     {
+        uint8_t psdu[Mac::Frame::kMTU];
         Mac::Frame frame;
+
+        frame.mPsdu = psdu;
+
         frame.InitMacHeader(tests[i].fcf, tests[i].secCtl);
         printf("%d\n", frame.GetHeaderLength());
         VerifyOrQuit(frame.GetHeaderLength() == tests[i].headerLength,