[mac] put transmission AES-CCM* to SubMac layer (#4919)

In Thread 1.2, it is possible to receive an IEEE 802.15.4-2015
packet. Per specification, receiver should acknowledge this packet
with an IEEE 802.15.4-2015 ACK(Enh-ACK). This Enh-ACK can include
header IE with it and requires security enabled bit in FCF be set to
true. It is impractical for the host to generate the Enh-ACK and send
to RCP for transmission within AIFS time(192us). So RCP should prepare
the Enh-ACK by itself, which requires it to fill in the frame counter
and do the encryption/authentication. This commit tries to address the
need of transmission security/authentication by including the
following changes,

- Move Key ID mode 1 AES-CCM* related functions from MAC layer to
  SubMac layer, which is mirrored in RCP.

- Distribute the MAC key and MAC key ID to RCP in posix app using
  newly added spinel properties.

- Make it possible for radio(either in radio driver or hardware) to do
  transmission AES-CCM* if the platform supports by adding radio
  capability OT_RADIO_CAPS_TRANSMIT_SEC.

- Enable this for RCP mode on simulation platform.

include/openthread/link_raw.h

@@ -330,6 +330,27 @@ otError otLinkRawSrcMatchClearShortEntries(otInstance *aInstance);
  */
 otError otLinkRawSrcMatchClearExtEntries(otInstance *aInstance);
 
+/**
+ * Update MAC keys and key index.
+ *
+ * @param[in]   aInstance    A pointer to an OpenThread instance.
+ * @param[in]   aKeyIdMode   The key ID mode.
+ * @param[in]   aKeyId       The key index.
+ * @param[in]   aPrevKey     The previous MAC key.
+ * @param[in]   aCurrKey     The current MAC key.
+ * @param[in]   aNextKey     The next MAC key.
+ *
+ * @retval OT_ERROR_NONE             If successful.
+ * @retval OT_ERROR_INVALID_STATE    If the raw link-layer isn't enabled.
+ *
+ */
+otError otLinkRawSetMacKey(otInstance *   aInstance,
+                           uint8_t        aKeyIdMode,
+                           uint8_t        aKeyId,
+                           const uint8_t *aPrevKey,
+                           const uint8_t *aCurrKey,
+                           const uint8_t *aNextKey);
+
 /**
  * @}
  *

include/openthread/platform/radio.h

@@ -124,6 +124,7 @@ enum
     OT_RADIO_CAPS_TRANSMIT_RETRIES = 1 << 2, ///< Radio supports tx retry logic with collision avoidance (CSMA).
     OT_RADIO_CAPS_CSMA_BACKOFF     = 1 << 3, ///< Radio supports CSMA backoff for frame transmission (but no retry).
     OT_RADIO_CAPS_SLEEP_TO_TX      = 1 << 4, ///< Radio supports direct transition from sleep to TX with CSMA.
+    OT_RADIO_CAPS_TRANSMIT_SEC     = 1 << 5, ///< Radio supports tx security.
 };
 
 #define OT_PANID_BROADCAST 0xffff ///< IEEE 802.15.4 Broadcast PAN ID
@@ -196,6 +197,7 @@ typedef struct otRadioFrame
             uint8_t        mMaxFrameRetries;   ///< Maximum number of retries allowed after a transmission failure.
             bool           mIsARetx : 1;       ///< True if this frame is a retransmission (ignored by radio driver).
             bool           mCsmaCaEnabled : 1; ///< Set to true to enable CSMA-CA for this packet, false otherwise.
+            bool           mIsSecurityProcessed : 1; ///< True if SubMac should skip the AES processing of this frame.
         } mTxInfo;
 
         /**
@@ -433,6 +435,28 @@ bool otPlatRadioGetPromiscuous(otInstance *aInstance);
  */
 void otPlatRadioSetPromiscuous(otInstance *aInstance, bool aEnable);
 
+/**
+ * Update MAC keys and key index
+ *
+ * This function is used when radio provides OT_RADIO_CAPS_TRANSMIT_SEC capability.
+ *
+ * @param[in]   aInstance    A pointer to an OpenThread instance.
+ * @param[in]   aKeyIdMode   The key ID mode.
+ * @param[in]   aKeyId       Current MAC key index.
+ * @param[in]   aKeySize     The key size.
+ * @param[in]   aPrevKey     A pointer to the previous MAC key.
+ * @param[in]   aCurrKey     A pointer to the current MAC key.
+ * @param[in]   aNextKey     A pointer to the next MAC key.
+ *
+ */
+void otPlatRadioSetMacKey(otInstance *   aInstance,
+                          uint8_t        aKeyIdMode,
+                          uint8_t        aKeyId,
+                          uint8_t        aKeySize,
+                          const uint8_t *aPrevKey,
+                          const uint8_t *aCurrKey,
+                          const uint8_t *aNextKey);
+
 /**
  * @}
  *