static SntpStatus_t parseValidSntpResponse()

in source/core_sntp_serializer.c [507:598]
57 lines of code
5 McCabe index (conditional complexity)

static SntpStatus_t parseValidSntpResponse( const SntpPacket_t * pResponsePacket,
                                            const SntpTimestamp_t * pRequestTxTime,
                                            const SntpTimestamp_t * pResponseRxTime,
                                            SntpResponseData_t * pParsedResponse )
{
    SntpStatus_t status = SntpSuccess;

    assert( pResponsePacket != NULL );
    assert( pResponseRxTime != NULL );
    assert( pParsedResponse != NULL );

    /* Clear the output parameter memory to zero. */
    ( void ) memset( pParsedResponse, 0, sizeof( *pParsedResponse ) );

    /* Determine if the server has accepted or rejected the request for time. */
    if( pResponsePacket->stratum == SNTP_KISS_OF_DEATH_STRATUM )
    {
        /* Server has sent a Kiss-o'-Death message i.e. rejected the request. */

        /* Extract the kiss-code sent by the server from the "Reference ID" field
         * of the SNTP packet. */
        pParsedResponse->rejectedResponseCode =
            readWordFromNetworkByteOrderMemory( &pResponsePacket->refId );

        /* Determine the return code based on the Kiss-o'-Death code. */
        switch( pParsedResponse->rejectedResponseCode )
        {
            case KOD_CODE_DENY_UINT_VALUE:
            case KOD_CODE_RSTR_UINT_VALUE:
                status = SntpRejectedResponseChangeServer;
                break;

            case KOD_CODE_RATE_UINT_VALUE:
                status = SntpRejectedResponseRetryWithBackoff;
                break;

            default:
                status = SntpRejectedResponseOtherCode;
                break;
        }
    }
    else
    {
        /* Server has responded successfully to the time request. */

        SntpTimestamp_t serverRxTime;

        /* Map of integer value to SntpLeapSecondInfo_t enumeration type for the
         * "Leap Indicator" field in the first byte of an SNTP packet.
         * Note: This map is used to not violate MISRA Rule 10.5 when directly
         * converting an integer to enumeration type.
         */
        const SntpLeapSecondInfo_t leapIndicatorTypeMap[] =
        {
            NoLeapSecond,
            LastMinuteHas61Seconds,
            LastMinuteHas59Seconds,
            AlarmServerNotSynchronized
        };

        /* Set the Kiss-o'-Death code value to NULL as server has responded favorably
         * to the time request. */
        pParsedResponse->rejectedResponseCode = SNTP_KISS_OF_DEATH_CODE_NONE;

        /* Fill the output parameter with the server time which is the
         * "transmit" time in the response packet. */
        pParsedResponse->serverTime.seconds =
            readWordFromNetworkByteOrderMemory( &pResponsePacket->transmitTime.seconds );
        pParsedResponse->serverTime.fractions =
            readWordFromNetworkByteOrderMemory( &pResponsePacket->transmitTime.fractions );

        /* Extract information of any upcoming leap second from the response. */
        pParsedResponse->leapSecondType = leapIndicatorTypeMap[
            ( pResponsePacket->leapVersionMode >> SNTP_LEAP_INDICATOR_LSB_POSITION ) ];

        /* Store the "receive" time in SNTP response packet in host order. */
        serverRxTime.seconds =
            readWordFromNetworkByteOrderMemory( &pResponsePacket->receiveTime.seconds );
        serverRxTime.fractions =
            readWordFromNetworkByteOrderMemory( &pResponsePacket->receiveTime.fractions );

        /* Calculate system clock offset relative to server time, if possible, within
         * the 64 bit integer width of the SNTP timestamp. */
        calculateClockOffset( pRequestTxTime,
                              &serverRxTime,
                              &pParsedResponse->serverTime,
                              pResponseRxTime,
                              &pParsedResponse->clockOffsetMs );
    }

    return status;
}