Statistics
| Branch: | Revision:

root / freemodbus / modbus / tcp / mbtcp.c @ 20e5429c

History | View | Annotate | Download (5.58 KB)

1
/* 
2
 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
3
 * Copyright (c) 2006 Christian Walter <wolti@sil.at>
4
 * All rights reserved.
5
 *
6
 * Redistribution and use in source and binary forms, with or without
7
 * modification, are permitted provided that the following conditions
8
 * are met:
9
 * 1. Redistributions of source code must retain the above copyright
10
 *    notice, this list of conditions and the following disclaimer.
11
 * 2. Redistributions in binary form must reproduce the above copyright
12
 *    notice, this list of conditions and the following disclaimer in the
13
 *    documentation and/or other materials provided with the distribution.
14
 * 3. The name of the author may not be used to endorse or promote products
15
 *    derived from this software without specific prior written permission.
16
 *
17
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
 *
28
 * File: $Id: mbtcp.c,v 1.3 2006/12/07 22:10:34 wolti Exp $
29
 */
30

    
31
/* ----------------------- System includes ----------------------------------*/
32
#include "stdlib.h"
33
#include "string.h"
34

    
35
/* ----------------------- Platform includes --------------------------------*/
36
#include "port.h"
37

    
38
/* ----------------------- Modbus includes ----------------------------------*/
39
#include "mb.h"
40
#include "mbconfig.h"
41
#include "mbtcp.h"
42
#include "mbframe.h"
43
#include "mbport.h"
44

    
45
#if MB_TCP_ENABLED > 0
46

    
47
/* ----------------------- Defines ------------------------------------------*/
48

    
49
/* ----------------------- MBAP Header --------------------------------------*/
50
/*
51
 *
52
 * <------------------------ MODBUS TCP/IP ADU(1) ------------------------->
53
 *              <----------- MODBUS PDU (1') ---------------->
54
 *  +-----------+---------------+------------------------------------------+
55
 *  | TID | PID | Length | UID  |Code | Data                               |
56
 *  +-----------+---------------+------------------------------------------+
57
 *  |     |     |        |      |                                           
58
 * (2)   (3)   (4)      (5)    (6)                                          
59
 *
60
 * (2)  ... MB_TCP_TID          = 0 (Transaction Identifier - 2 Byte) 
61
 * (3)  ... MB_TCP_PID          = 2 (Protocol Identifier - 2 Byte)
62
 * (4)  ... MB_TCP_LEN          = 4 (Number of bytes - 2 Byte)
63
 * (5)  ... MB_TCP_UID          = 6 (Unit Identifier - 1 Byte)
64
 * (6)  ... MB_TCP_FUNC         = 7 (Modbus Function Code)
65
 *
66
 * (1)  ... Modbus TCP/IP Application Data Unit
67
 * (1') ... Modbus Protocol Data Unit
68
 */
69

    
70
#define MB_TCP_TID          0
71
#define MB_TCP_PID          2
72
#define MB_TCP_LEN          4
73
#define MB_TCP_UID          6
74
#define MB_TCP_FUNC         7
75

    
76
#define MB_TCP_PROTOCOL_ID  0   /* 0 = Modbus Protocol */
77

    
78

    
79
/* ----------------------- Start implementation -----------------------------*/
80
eMBErrorCode
81
eMBTCPDoInit( USHORT ucTCPPort )
82
{
83
    eMBErrorCode    eStatus = MB_ENOERR;
84

    
85
    if( xMBTCPPortInit( ucTCPPort ) == FALSE )
86
    {
87
        eStatus = MB_EPORTERR;
88
    }
89
    return eStatus;
90
}
91

    
92
void
93
eMBTCPStart( void )
94
{
95
}
96

    
97
void
98
eMBTCPStop( void )
99
{
100
    /* Make sure that no more clients are connected. */
101
    vMBTCPPortDisable( );
102
}
103

    
104
eMBErrorCode
105
eMBTCPReceive( UCHAR * pucRcvAddress, UCHAR ** ppucFrame, USHORT * pusLength )
106
{
107
    eMBErrorCode    eStatus = MB_EIO;
108
    UCHAR          *pucMBTCPFrame;
109
    USHORT          usLength;
110
    USHORT          usPID;
111

    
112
    if( xMBTCPPortGetRequest( &pucMBTCPFrame, &usLength ) != FALSE )
113
    {
114
        usPID = pucMBTCPFrame[MB_TCP_PID] << 8U;
115
        usPID |= pucMBTCPFrame[MB_TCP_PID + 1];
116

    
117
        if( usPID == MB_TCP_PROTOCOL_ID )
118
        {
119
            *ppucFrame = &pucMBTCPFrame[MB_TCP_FUNC];
120
            *pusLength = usLength - MB_TCP_FUNC;
121
            eStatus = MB_ENOERR;
122

    
123
            /* Modbus TCP does not use any addresses. Fake the source address such
124
             * that the processing part deals with this frame.
125
             */
126
            *pucRcvAddress = MB_TCP_PSEUDO_ADDRESS;
127
        }
128
    }
129
    else
130
    {
131
        eStatus = MB_EIO;
132
    }
133
    return eStatus;
134
}
135

    
136
eMBErrorCode
137
eMBTCPSend( UCHAR _unused, const UCHAR * pucFrame, USHORT usLength )
138
{
139
    eMBErrorCode    eStatus = MB_ENOERR;
140
    UCHAR          *pucMBTCPFrame = ( UCHAR * ) pucFrame - MB_TCP_FUNC;
141
    USHORT          usTCPLength = usLength + MB_TCP_FUNC;
142

    
143
    /* The MBAP header is already initialized because the caller calls this
144
     * function with the buffer returned by the previous call. Therefore we 
145
     * only have to update the length in the header. Note that the length 
146
     * header includes the size of the Modbus PDU and the UID Byte. Therefore 
147
     * the length is usLength plus one.
148
     */
149
    pucMBTCPFrame[MB_TCP_LEN] = ( usLength + 1 ) >> 8U;
150
    pucMBTCPFrame[MB_TCP_LEN + 1] = ( usLength + 1 ) & 0xFF;
151
    if( xMBTCPPortSendResponse( pucMBTCPFrame, usTCPLength ) == FALSE )
152
    {
153
        eStatus = MB_EIO;
154
    }
155
    return eStatus;
156
}
157

    
158
#endif