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📄 rfccontrol.c

📁 IT projecotr reference design.
💻 C
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                        /****************************************************/

    startSend();

    sendByte( DLE );
    sendByte( STX );

                        /****************************************************/
                        /* Send response message text.                      */
                        /****************************************************/

    while( msgSize-- ) translateByte( *p++ );

                        /****************************************************/
                        /* Send CRC.                                        */
                        /****************************************************/

    translateByte( crc >> 8 );
    translateByte( crc & 0xff );

                        /****************************************************/
                        /* End text.                                        */
                        /****************************************************/

    sendByte( DLE );
    sendByte( ETX );

    endSend();
}



/****************************************************************************/
/* Receive an RFC request message.                                          */
/****************************************************************************/

                        /****************************************************/
                        /*  Message receiver FSM states.                    */
                        /****************************************************/

typedef enum _receiverstate
{
    RSM_IDLE,                                      /* state machine is idle */
    RSM_LEADINGDLE,                                 /* leading DLE detected */
    RSM_RECV,                                     /* receiving message text */
    RSM_TEXTDLE                             /* received DLE in message text */
}
    RSM_ENUM;

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

static void rfcMsgReceive( void )
{
    RSM_ENUM rsmState = RSM_IDLE;           /* receiver state machine state */

    int     dllimit = 0;               /* limit of bytes in internal buffer */
    int     dlindex = 0;                      /* index into internal buffer */
    int     tcount;                                   /* message byte count */
    uint08 *pMsg    = (uint08*)pRFCMsg;            /* message as byte array */

                        /****************************************************/
                        /*  Run until a complete message is received.       */
                        /****************************************************/

    for(;;)
    {
                        /****************************************************/
                        /* Parse from an internal buffer to avoid the       */
                        /* overhead of a call per character.                */
                        /****************************************************/

        if( dlindex >= dllimit )
        {
            dlindex = 0;
            dllimit = (*readFunc)( pTBuffer );
        }

                        /****************************************************/
                        /* Fetch all chars from the internal buffer.        */
                        /****************************************************/

        while( dlindex < dllimit )
        {
            char k = pTBuffer[ dlindex++ ];

            switch( rsmState )
            {
                        /****************************************************/
                        /* Waiting for initial DLE.                         */
                        /****************************************************/

                case RSM_IDLE:
                    if( DLE == k )
                        rsmState = RSM_LEADINGDLE;

                    break;

                        /****************************************************/
                        /* Leading DLE detected.                            */
                        /****************************************************/

                case RSM_LEADINGDLE:
unexpectedDLE:
                    if( STX == k )                      /* start of message */
                    {
                        rsmState = RSM_RECV;
                        tcount   = 0;                    /* zero text bytes */

                    }

                    else if( DLE != k )              /* unexpected DLE-pair */
                        rsmState = RSM_IDLE;

                    break;

                        /****************************************************/
                        /* Receiving text.                                  */
                        /****************************************************/

                case RSM_RECV:
                    if( DLE == k )                     /* start of DLE-pair */
                    {
                        rsmState = RSM_TEXTDLE;
                        break;
                    }
continueRECV:
                    if( tcount >= sizeof( RFCMESSAGE )) /* if text overflow */
                        rsmState = RSM_IDLE;            /* restart receiver */
                    else
                        pMsg[ tcount++ ] = k;             /* copy text byte */

                    break;

                        /****************************************************/
                        /* Received DLE in text.                            */
                        /****************************************************/

                case RSM_TEXTDLE:
                    if( DLC == k )                      /* DLE substitution */
                    {
                        k = DLE;                              /* substitute */
                        rsmState = RSM_RECV;               /* receive state */
                        goto continueRECV;                      /* continue */
                    }

                        /****************************************************/
                        /*  On ETX, test the CRC and call the RFC handler.  */
                        /****************************************************/

                    else if( ETX == k )                      /* end of text */
                    {
                        uint16 crc;                          /* message CRC */

                        rsmState = RSM_IDLE;            /* restart receiver */

                        crc = crc16( pMsg, tcount, CRC_SEED );

                        if( 0 == crc )
                        {
                            nRemReadRFC = pRFCMsg -> h.szReq;
                            rfcExec();
                        }
                    }

                    else
                    {
                        rsmState = RSM_LEADINGDLE;        /* unexpected DLE */
                        goto unexpectedDLE;
                    }

                    break;
            }
        }
    }
}



/****************************************************************************/
/* Execute RFC call.                                                        */
/****************************************************************************/

static void rfcExec( void )
{
    int32 fx;                              /* RFC function dictionary index */

    pReq         = pRFCMsg -> mBuffer;          /* pointer into RFC request */
    pRsp         = pRFCMsg -> mBuffer;         /* pointer into RFC response */
    nWrittenRFC  = 0;                   /* number of response bytes written */
    nRemWriteRFC = pRFCMsg -> h.szRsp;        /* max number of return bytes */

    if( nRemWriteRFC > MBUFFERSIZE ) nRemWriteRFC = MBUFFERSIZE;   /* limit */

    dbmsg_ftrace( DBM_MSG, "rfc: %04x ", pRFCMsg -> h.transID );

    if( VERSION_TRANSACTION_ID == pRFCMsg -> h.transID ) /* version request */
    {
        uint16 t = RFCID_VERSION;

        dbmsg_trace( DBM_MSG, "VERSION_TRANSACTION\r\n" );
        rfcMPPut( 2, &t );
    }

    else if( -1 != ( fx = rfcDictFind(pRFCMsg -> h.transID )))   /* invalid */
    {
        dbmsg_ftrace( DBM_MSG, "%s\r\n", xf_Dictionary[fx].fName );
        (*xf_Dictionary[fx].pFunc)();                      /* exec function */
    }

    else
    {
        dbmsg_trace( DBM_MSG, "** unknown **\r\n" );
    }

    rfcMsgTransmit();                                    /* return response */
}



/****************************************************************************/
/* Perform a binary search of the function dictionary on the transaction ID */
/* and return the dictionary index if found.                                */
/*                                                                          */
/* pTrans - pointer to a TRANSADL_STRUCT whose API function is to           */
/*          be located.                                                     */
/*                                                                          */
/* Returns:                                                                 */
/*   Dictionary index, or -1 if entry not found.                            */
/****************************************************************************/

static int32 rfcDictFind( uint16 funcID )
{
    int32 low  = -1;
    int32 high = xf_dictSize;
    int32 probe;

    while(( high - low ) > 1 )
    {
        probe = ( high + low ) / 2;

        if ( xf_Dictionary[probe].key > funcID )
            high = probe;
         else
            low = probe;
    }

    if(( low == -1 ) || ( xf_Dictionary[low].key != funcID ))
        return -1;
    else
        return low;
}



/****************************************************************************/
/* Get a parameter from an RFC request message.                             */
/*                                                                          */
/* nBytes - Number of sequential bytes to fetch from request                */
/*   parm - Pointer to location at which to store parameter                 */
/****************************************************************************/

void rfcMPGet( int nBytes, void *parm )
{
    if( nRemReadRFC < nBytes )
    {
        dbmsg_trace( DBM_ALWAYS, "rfcMPGet can't read parameter\r\n" );
        return;
    }

    memcpy( parm, pReq, nBytes );                      /* copy from message */
    pReq += nBytes;                                         /* bump pointer */
    nRemReadRFC -= nBytes;                                    /* bump count */
}



/****************************************************************************/
/* Put a parameter to an RFC response message;                              */
/*                                                                          */
/* nBytes - Number of sequential bytes to store in response                 */
/*   parm - Pointer to location from which to fetch parameter               */
/****************************************************************************/

void rfcMPPut( int nBytes, void *parm )
{
    if( nRemWriteRFC < nBytes )
    {
        dbmsg_trace( DBM_ALWAYS, "rfcMPPut can't write parameter\r\n" );
        return;
    }

    memcpy( pRsp, parm, nBytes );                        /* copy to message */
    pRsp         += nBytes;                                 /* bump pointer */
    nWrittenRFC  += nBytes;                           /* bump count written */
    nRemWriteRFC -= nBytes;                         /* bump count remaining */
}



/****************************************************************************/
/* CCITT-CRC16 lookup table.                                                */
/****************************************************************************/

static const uint16 crc16table[ 256 ] =
{
  0x0000,0x1021,0x2042,0x3063,0x4084,0x50A5,0x60C6,0x70E7,
  0x8108,0x9129,0xA14A,0xB16B,0xC18C,0xD1AD,0xE1CE,0xF1EF,
  0x1231,0x0210,0x3273,0x2252,0x52B5,0x4294,0x72F7,0x62D6,
  0x9339,0x8318,0xB37B,0xA35A,0xD3BD,0xC39C,0xF3FF,0xE3DE,
  0x2462,0x3443,0x0420,0x1401,0x64E6,0x74C7,0x44A4,0x5485,
  0xA56A,0xB54B,0x8528,0x9509,0xE5EE,0xF5CF,0xC5AC,0xD58D,
  0x3653,0x2672,0x1611,0x0630,0x76D7,0x66F6,0x5695,0x46B4,
  0xB75B,0xA77A,0x9719,0x8738,0xF7DF,0xE7FE,0xD79D,0xC7BC,
  0x48C4,0x58E5,0x6886,0x78A7,0x0840,0x1861,0x2802,0x3823,
  0xC9CC,0xD9ED,0xE98E,0xF9AF,0x8948,0x9969,0xA90A,0xB92B,
  0x5AF5,0x4AD4,0x7AB7,0x6A96,0x1A71,0x0A50,0x3A33,0x2A12,
  0xDBFD,0xCBDC,0xFBBF,0xEB9E,0x9B79,0x8B58,0xBB3B,0xAB1A,
  0x6CA6,0x7C87,0x4CE4,0x5CC5,0x2C22,0x3C03,0x0C60,0x1C41,
  0xEDAE,0xFD8F,0xCDEC,0xDDCD,0xAD2A,0xBD0B,0x8D68,0x9D49,
  0x7E97,0x6EB6,0x5ED5,0x4EF4,0x3E13,0x2E32,0x1E51,0x0E70,
  0xFF9F,0xEFBE,0xDFDD,0xCFFC,0xBF1B,0xAF3A,0x9F59,0x8F78,
  0x9188,0x81A9,0xB1CA,0xA1EB,0xD10C,0xC12D,0xF14E,0xE16F,
  0x1080,0x00A1,0x30C2,0x20E3,0x5004,0x4025,0x7046,0x6067,
  0x83B9,0x9398,0xA3FB,0xB3DA,0xC33D,0xD31C,0xE37F,0xF35E,
  0x02B1,0x1290,0x22F3,0x32D2,0x4235,0x5214,0x6277,0x7256,
  0xB5EA,0xA5CB,0x95A8,0x8589,0xF56E,0xE54F,0xD52C,0xC50D,
  0x34E2,0x24C3,0x14A0,0x0481,0x7466,0x6447,0x5424,0x4405,
  0xA7DB,0xB7FA,0x8799,0x97B8,0xE75F,0xF77E,0xC71D,0xD73C,
  0x26D3,0x36F2,0x0691,0x16B0,0x6657,0x7676,0x4615,0x5634,
  0xD94C,0xC96D,0xF90E,0xE92F,0x99C8,0x89E9,0xB98A,0xA9AB,
  0x5844,0x4865,0x7806,0x6827,0x18C0,0x08E1,0x3882,0x28A3,
  0xCB7D,0xDB5C,0xEB3F,0xFB1E,0x8BF9,0x9BD8,0xABBB,0xBB9A,
  0x4A75,0x5A54,0x6A37,0x7A16,0x0AF1,0x1AD0,0x2AB3,0x3A92,
  0xFD2E,0xED0F,0xDD6C,0xCD4D,0xBDAA,0xAD8B,0x9DE8,0x8DC9,
  0x7C26,0x6C07,0x5C64,0x4C45,0x3CA2,0x2C83,0x1CE0,0x0CC1,
  0xEF1F,0xFF3E,0xCF5D,0xDF7C,0xAF9B,0xBFBA,0x8FD9,0x9FF8,
  0x6E17,0x7E36,0x4E55,0x5E74,0x2E93,0x3EB2,0x0ED1,0x1EF0
};



/****************************************************************************/
/* CCITT-CRC16 lookup table.                                                */
/****************************************************************************/

uint16 crc16( void *text, int cc, uint16 crc )
{
    uint08 *p = (uint08*)text;

    while( cc-- )
        crc = (uint16)(( crc << 8 ) ^ crc16table[ ( crc >> 8 ) ^ *p++ ] );

    return crc;
}

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