164 lines
5.5 KiB
C
164 lines
5.5 KiB
C
/****************************************************************************
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* apps/modbus/tcp/mbtcp.c
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*
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* FreeModbus Library: A portable Modbus implementation for Modbus ASCII/RTU.
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* Copyright (c) 2006 Christian Walter <wolti@sil.at>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdlib.h>
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#include <string.h>
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#include "modbus/mb.h"
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#include "port.h"
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#include "mbtcp.h"
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#ifdef CONFIG_MB_TCP_ENABLED
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* ----------------------- MBAP Header --------------------------------------*/
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/*
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*
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* <------------------------ MODBUS TCP/IP ADU(1) ------------------------->
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* <----------- MODBUS PDU (1') ---------------->
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* +-----------+---------------+------------------------------------------+
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* | TID | PID | Length | UID |Code | Data |
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* +-----------+---------------+------------------------------------------+
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* | | | | |
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* (2) (3) (4) (5) (6)
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*
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* (2) ... MB_TCP_TID = 0 (Transaction Identifier - 2 Byte)
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* (3) ... MB_TCP_PID = 2 (Protocol Identifier - 2 Byte)
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* (4) ... MB_TCP_LEN = 4 (Number of bytes - 2 Byte)
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* (5) ... MB_TCP_UID = 6 (Unit Identifier - 1 Byte)
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* (6) ... MB_TCP_FUNC = 7 (Modbus Function Code)
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*
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* (1) ... Modbus TCP/IP Application Data Unit
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* (1') ... Modbus Protocol Data Unit
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*/
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#define MB_TCP_TID 0
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#define MB_TCP_PID 2
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#define MB_TCP_LEN 4
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#define MB_TCP_UID 6
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#define MB_TCP_FUNC 7
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#define MB_TCP_PROTOCOL_ID 0 /* 0 = Modbus Protocol */
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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eMBErrorCode eMBTCPDoInit(uint16_t ucTCPPort)
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{
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eMBErrorCode eStatus = MB_ENOERR;
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if (xMBTCPPortInit(ucTCPPort) == false)
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{
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eStatus = MB_EPORTERR;
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}
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return eStatus;
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}
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void eMBTCPStart(void)
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{
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}
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void eMBTCPStop(void)
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{
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/* Make sure that no more clients are connected. */
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vMBTCPPortDisable();
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}
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eMBErrorCode eMBTCPReceive(uint8_t *pucRcvAddress, uint8_t **ppucFrame, uint16_t *pusLength)
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{
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eMBErrorCode eStatus = MB_EIO;
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uint8_t *pucMBTCPFrame;
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uint16_t usLength;
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uint16_t usPID;
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if (xMBTCPPortGetRequest(&pucMBTCPFrame, &usLength) != false)
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{
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usPID = pucMBTCPFrame[MB_TCP_PID] << 8U;
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usPID |= pucMBTCPFrame[MB_TCP_PID + 1];
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if (usPID == MB_TCP_PROTOCOL_ID)
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{
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*ppucFrame = &pucMBTCPFrame[MB_TCP_FUNC];
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*pusLength = usLength - MB_TCP_FUNC;
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eStatus = MB_ENOERR;
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/* Modbus TCP does not use any addresses. Fake the source address such
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* that the processing part deals with this frame.
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*/
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*pucRcvAddress = MB_TCP_PSEUDO_ADDRESS;
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}
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}
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else
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{
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eStatus = MB_EIO;
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}
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return eStatus;
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}
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eMBErrorCode eMBTCPSend(uint8_t _unused, const uint8_t * pucFrame, uint16_t usLength)
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{
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eMBErrorCode eStatus = MB_ENOERR;
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uint8_t *pucMBTCPFrame = (uint8_t *) pucFrame - MB_TCP_FUNC;
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uint16_t usTCPLength = usLength + MB_TCP_FUNC;
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/* The MBAP header is already initialized because the caller calls this
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* function with the buffer returned by the previous call. Therefore we
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* only have to update the length in the header. Note that the length
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* header includes the size of the Modbus PDU and the UID Byte. Therefore
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* the length is usLength plus one.
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*/
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pucMBTCPFrame[MB_TCP_LEN] = (usLength + 1) >> 8U;
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pucMBTCPFrame[MB_TCP_LEN + 1] = (usLength + 1) & 0xFF;
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if (xMBTCPPortSendResponse(pucMBTCPFrame, usTCPLength) == false)
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{
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eStatus = MB_EIO;
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}
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return eStatus;
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}
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#endif /* CONFIG_MB_TCP_ENABLED */
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