Tooltron

/* 

 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.

 * Copyright (c) 2006 Christian Walter <wolti@sil.at>

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. The name of the author may not be used to endorse or promote products

 *    derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * File: $Id: mbtcp.c,v 1.3 2006/12/07 22:10:34 wolti Exp $

 */

/* ----------------------- System includes ----------------------------------*/

#include "stdlib.h"

#include "string.h"

/* ----------------------- Platform includes --------------------------------*/

#include "port.h"

/* ----------------------- Modbus includes ----------------------------------*/

#include "mb.h"

#include "mbconfig.h"

#include "mbtcp.h"

#include "mbframe.h"

#include "mbport.h"

#if MB_TCP_ENABLED > 0

/* ----------------------- Defines ------------------------------------------*/

/* ----------------------- MBAP Header --------------------------------------*/

/*

 *

 * <------------------------ MODBUS TCP/IP ADU(1) ------------------------->

 *              <----------- MODBUS PDU (1') ---------------->

 *  +-----------+---------------+------------------------------------------+

 *  | TID | PID | Length | UID  |Code | Data                               |

 *  +-----------+---------------+------------------------------------------+

 *  |     |     |        |      |                                           

 * (2)   (3)   (4)      (5)    (6)                                          

 *

 * (2)  ... MB_TCP_TID          = 0 (Transaction Identifier - 2 Byte) 

 * (3)  ... MB_TCP_PID          = 2 (Protocol Identifier - 2 Byte)

 * (4)  ... MB_TCP_LEN          = 4 (Number of bytes - 2 Byte)

 * (5)  ... MB_TCP_UID          = 6 (Unit Identifier - 1 Byte)

 * (6)  ... MB_TCP_FUNC         = 7 (Modbus Function Code)

 *

 * (1)  ... Modbus TCP/IP Application Data Unit

 * (1') ... Modbus Protocol Data Unit

 */

#define MB_TCP_TID          0

#define MB_TCP_PID          2

#define MB_TCP_LEN          4

#define MB_TCP_UID          6

#define MB_TCP_FUNC         7

#define MB_TCP_PROTOCOL_ID  0   /* 0 = Modbus Protocol */

/* ----------------------- Start implementation -----------------------------*/

eMBErrorCode

eMBTCPDoInit( USHORT ucTCPPort )

{

    eMBErrorCode    eStatus = MB_ENOERR;

    if( xMBTCPPortInit( ucTCPPort ) == FALSE )

    {

        eStatus = MB_EPORTERR;

    }

    return eStatus;

}

void

eMBTCPStart( void )

{

}

void

eMBTCPStop( void )

{

    /* Make sure that no more clients are connected. */

    vMBTCPPortDisable( );

}

eMBErrorCode

eMBTCPReceive( UCHAR * pucRcvAddress, UCHAR ** ppucFrame, USHORT * pusLength )

{

    eMBErrorCode    eStatus = MB_EIO;

    UCHAR          *pucMBTCPFrame;

    USHORT          usLength;

    USHORT          usPID;

    if( xMBTCPPortGetRequest( &pucMBTCPFrame, &usLength ) != FALSE )

    {

        usPID = pucMBTCPFrame[MB_TCP_PID] << 8U;

        usPID |= pucMBTCPFrame[MB_TCP_PID + 1];

        if( usPID == MB_TCP_PROTOCOL_ID )

        {

            *ppucFrame = &pucMBTCPFrame[MB_TCP_FUNC];

            *pusLength = usLength - MB_TCP_FUNC;

            eStatus = MB_ENOERR;

            /* Modbus TCP does not use any addresses. Fake the source address such

             * that the processing part deals with this frame.

             */

            *pucRcvAddress = MB_TCP_PSEUDO_ADDRESS;

        }

    }

    else

    {

        eStatus = MB_EIO;

    }

    return eStatus;

}

eMBErrorCode

eMBTCPSend( UCHAR _unused, const UCHAR * pucFrame, USHORT usLength )

{

    eMBErrorCode    eStatus = MB_ENOERR;

    UCHAR          *pucMBTCPFrame = ( UCHAR * ) pucFrame - MB_TCP_FUNC;

    USHORT          usTCPLength = usLength + MB_TCP_FUNC;

    /* The MBAP header is already initialized because the caller calls this

     * function with the buffer returned by the previous call. Therefore we 

     * only have to update the length in the header. Note that the length 

     * header includes the size of the Modbus PDU and the UID Byte. Therefore 

     * the length is usLength plus one.

     */

    pucMBTCPFrame[MB_TCP_LEN] = ( usLength + 1 ) >> 8U;

    pucMBTCPFrame[MB_TCP_LEN + 1] = ( usLength + 1 ) & 0xFF;

    if( xMBTCPPortSendResponse( pucMBTCPFrame, usTCPLength ) == FALSE )

    {

        eStatus = MB_EIO;

    }

    return eStatus;

}

#endif