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/****************************************************************************
* apps/modbus/tcp/mbtcp.c
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdlib.h>
#include <string.h>
#include <apps/modbus/mb.h>
#include "port.h"
#include "mbtcp.h"
#ifdef CONFIG_MB_TCP_ENABLED
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* ----------------------- 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 */
/****************************************************************************
* Public Functions
****************************************************************************/
eMBErrorCode eMBTCPDoInit(uint16_t 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(uint8_t *pucRcvAddress, uint8_t **ppucFrame, uint16_t *pusLength)
{
eMBErrorCode eStatus = MB_EIO;
uint8_t *pucMBTCPFrame;
uint16_t usLength;
uint16_t 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(uint8_t _unused, const uint8_t * pucFrame, uint16_t usLength)
{
eMBErrorCode eStatus = MB_ENOERR;
uint8_t *pucMBTCPFrame = (uint8_t *) pucFrame - MB_TCP_FUNC;
uint16_t 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
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