/***********************************************************************************
  Filename:     basic_rf.c

  Description:  Basic RF library

***********************************************************************************/

/***********************************************************************************
* INCLUDES
*/
#include "hal_int.h"
#include "hal_mcu.h"            // Using halMcuWaitUs()

#include "hal_rf.h"
#ifdef SECURITY_CCM
#include "hal_rf_security.h"
#endif

#include "basic_rf.h"
#ifdef SECURITY_CCM
#include "basic_rf_security.h"
#endif

#include "util.h"               // Using min()
#include "string.h"

/***********************************************************************************
* CONSTANTS AND DEFINES
*/

// Packet and packet part lengths
#define PKT_LEN_MIC                         8
#define PKT_LEN_SEC                         PKT_LEN_UNSEC + PKT_LEN_MIC
#define PKT_LEN_AUTH                        8
#define PKT_LEN_ENCR                        24

// Packet overhead ((frame control field, sequence number, PAN ID,
// destination and source) + (footer))
// Note that the length byte itself is not included included in the packet length
#define BASIC_RF_PACKET_OVERHEAD_SIZE       ((2 + 1 + 2 + 2 + 2) + (2))
#define BASIC_RF_MAX_PAYLOAD_SIZE	        (127 - BASIC_RF_PACKET_OVERHEAD_SIZE - \
    BASIC_RF_AUX_HDR_LENGTH - BASIC_RF_LEN_MIC)
#define BASIC_RF_ACK_PACKET_SIZE	        5
#define BASIC_RF_FOOTER_SIZE                2

// The time it takes for the acknowledgment packet to be received after the
// data packet has been transmitted.
#define BASIC_RF_ACK_DURATION		        (0.5 * 32 * 2 * ((4 + 1) + (1) + (2 + 1) + (2)))
#define BASIC_RF_SYMBOL_DURATION	        (32 * 0.5)

// The length byte
#define BASIC_RF_PLD_LEN_MASK               0x7F

// Frame control field
#define BASIC_RF_FCF_NOACK                  0x8841
#define BASIC_RF_FCF_ACK                    0x8861
#define BASIC_RF_FCF_ACK_BM                 0x0020
#define BASIC_RF_FCF_BM                     (~BASIC_RF_FCF_ACK_BM)
#define BASIC_RF_ACK_FCF		            0x0002
#define BASIC_RF_SEC_ENABLED_FCF_BM         0x0008

// Auxiliary Security header
#define BASIC_RF_AUX_HDR_LENGTH             5
#define BASIC_RF_LEN_AUTH                   BASIC_RF_PACKET_OVERHEAD_SIZE + \
    BASIC_RF_AUX_HDR_LENGTH - BASIC_RF_FOOTER_SIZE
#define BASIC_RF_SECURITY_M                 2
#define BASIC_RF_LEN_MIC                    8

// Footer
#define BASIC_RF_CRC_OK_BM                  0x80

/***********************************************************************************
* TYPEDEFS
*/
// The receive struct
typedef struct {
    uint8 seqNumber;
    uint16 srcAddr;
    uint16 srcPanId;
    int8 length;
    uint8* pPayload;
    uint8 ackRequest;
    int8 rssi;
    volatile uint8 isReady;
    uint8 status;
} basicRfRxInfo_t;

// Tx state
typedef struct {
    uint8 txSeqNumber;
    volatile uint8 ackReceived;
    uint8 receiveOn;
    uint32 frameCounter;
} basicRfTxState_t;


// Basic RF packet header (IEEE 802.15.4)
#ifdef __ICC430__
#pragma pack(1)
#endif
typedef struct {
    uint8   packetLength;
    uint16  frameControlField;
    uint8   seqNumber;
    uint16  panId;
    uint16  destAddr;
    uint16  srcAddr;
    #ifdef SECURITY_CCM
    uint8   securityControl;
    uint32  frameCounter;
    #endif
} basicRfPktHdr_t;
#ifdef __ICC430__
#pragma pack()
#endif


/***********************************************************************************
* LOCAL VARIABLES
*/
static basicRfRxInfo_t  rxi=      { 0xFF }; // Make sure sequence numbers are
static basicRfTxState_t txState=  { 0x00 }; // initialised and distinct.

static basicRfCfg_t* pConfig;
static uint8 txMpdu[BASIC_RF_MAX_PAYLOAD_SIZE+BASIC_RF_PACKET_OVERHEAD_SIZE+1];
static uint8 rxMpdu[BASIC_RF_MAX_PAYLOAD_SIZE+BASIC_RF_PACKET_OVERHEAD_SIZE+1];

/***********************************************************************************
* GLOBAL VARIABLES
*/


/***********************************************************************************
* LOCAL FUNCTIONS
*/
static uint8 basicRfBuildHeader(uint8* buffer, uint16 destAddr, uint8 payloadLength);
static uint8 basicRfBuildMpdu(uint16 destAddr, uint8* pPayload, uint8 length);
static void basicRfRxFrmDoneIsr(void);



/***********************************************************************************
* @fn          basicRfBuildHeader
*
* @brief       Builds packet header according to IEEE 802.15.4 frame format
*
* @param       buffer - Pointer to buffer to write the header
*              destAddr - destination short address
*              payloadLength - length of higher layer payload
*
* @return      uint8 - length of header
*/
static uint8 basicRfBuildHeader(uint8* buffer, uint16 destAddr, uint8 payloadLength)
{
    basicRfPktHdr_t *pHdr;

    pHdr= (basicRfPktHdr_t*)buffer;

    // Populate packet header
    pHdr->packetLength = payloadLength + BASIC_RF_PACKET_OVERHEAD_SIZE;
    pHdr->frameControlField = pConfig->ackRequest ? BASIC_RF_FCF_ACK : BASIC_RF_FCF_NOACK;
    pHdr->seqNumber= txState.txSeqNumber;
    pHdr->panId= pConfig->panId;
    pHdr->destAddr= destAddr;
    pHdr->srcAddr= pConfig->myAddr;

    #ifdef SECURITY_CCM

    // Add security to FCF, length and security header
    pHdr->frameControlField |= BASIC_RF_SEC_ENABLED_FCF_BM;
    pHdr->packetLength += PKT_LEN_MIC;
    pHdr->packetLength += BASIC_RF_AUX_HDR_LENGTH;

    pHdr->securityControl= SECURITY_CONTROL;
    pHdr->frameCounter=   txState.frameCounter;

    #endif

    // Make sure bytefields are network byte order
    UINT16_HTON(pHdr->frameControlField);
    UINT16_HTON(pHdr->panId);
    UINT16_HTON(pHdr->destAddr);
    UINT16_HTON(pHdr->srcAddr);

    return sizeof(basicRfPktHdr_t);
}


/***********************************************************************************
* @fn          basicRfBuildMpdu
*
* @brief       Builds mpdu (MAC header + payload) according to IEEE 802.15.4
*              frame format
*
* @param       destAddr - Destination short address
*              pPayload - pointer to buffer with payload
*              payloadLength - length of payload buffer
*
* @return      uint8 - length of mpdu
*/
static uint8 basicRfBuildMpdu(uint16 destAddr, uint8* pPayload, uint8 payloadLength)
{
    uint8 hdrLength, n;

    hdrLength = basicRfBuildHeader(txMpdu, destAddr, payloadLength);

    for(n=0;n<payloadLength;n++)
    {
        txMpdu[hdrLength+n] = pPayload[n];
    }
    return hdrLength + payloadLength; // total mpdu length
}


/***********************************************************************************
* @fn          basicRfRxFrmDoneIsr
*
* @brief       Interrupt service routine for received frame from radio
*              (either data or acknowlegdement)
*
* @param       rxi - file scope variable info extracted from the last incoming
*                    frame
*              txState - file scope variable that keeps tx state info
*
* @return      none
*/
static void basicRfRxFrmDoneIsr(void)
{
    basicRfPktHdr_t *pHdr;
    uint8 *pStatusWord;
    #ifdef SECURITY_CCM
    uint8 authStatus=0;
    #endif

    // Map header to packet buffer
    pHdr= (basicRfPktHdr_t*)rxMpdu;

    // Clear interrupt and disable new RX frame done interrupt
    halRfDisableRxInterrupt();

    // Enable all other interrupt sources (enables interrupt nesting)
    halIntOn();

    // Read payload length.
    halRfReadRxBuf(&pHdr->packetLength,1);
    pHdr->packetLength &= BASIC_RF_PLD_LEN_MASK; // Ignore MSB

    // Is this an acknowledgment packet?
    // Only ack packets may be 5 bytes in total.
    if (pHdr->packetLength == BASIC_RF_ACK_PACKET_SIZE) {

        // Read the packet
        halRfReadRxBuf(&rxMpdu[1], pHdr->packetLength);

        // Make sure byte fields are changed from network to host byte order
        UINT16_NTOH(pHdr->frameControlField);
    	UINT16_NTOH(pHdr->panId);
    	UINT16_NTOH(pHdr->destAddr);
    	UINT16_NTOH(pHdr->srcAddr);
        #ifdef SECURITY_CCM
        UINT32_NTOH(pHdr->frameCounter);
        #endif

        rxi.ackRequest = !!(pHdr->frameControlField & BASIC_RF_FCF_ACK_BM);

        // Read the status word and check for CRC OK
        pStatusWord= rxMpdu + 4;

        // Indicate the successful ACK reception if CRC and sequence number OK
        if ((pStatusWord[1] & BASIC_RF_CRC_OK_BM) && (pHdr->seqNumber == txState.txSeqNumber)) {
            txState.ackReceived = TRUE;
        }

        // No, it is data
    } else {

        // It is assumed that the radio rejects packets with invalid length.
        // Subtract the number of bytes in the frame overhead to get actual payload.

        rxi.length = pHdr->packetLength - BASIC_RF_PACKET_OVERHEAD_SIZE;

        #ifdef SECURITY_CCM
        rxi.length -= (BASIC_RF_AUX_HDR_LENGTH + BASIC_RF_LEN_MIC);
        authStatus = halRfReadRxBufSecure(&rxMpdu[1], pHdr->packetLength, rxi.length,
                                        BASIC_RF_LEN_AUTH, BASIC_RF_SECURITY_M);
        #else
        halRfReadRxBuf(&rxMpdu[1], pHdr->packetLength);
        #endif

        // Make sure byte fields are changed from network to host byte order
        UINT16_NTOH(pHdr->frameControlField);
    	UINT16_NTOH(pHdr->panId);
    	UINT16_NTOH(pHdr->destAddr);
    	UINT16_NTOH(pHdr->srcAddr);
        #ifdef SECURITY_CCM
        UINT32_NTOH(pHdr->frameCounter);