modbus-private.h
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/*
* Copyright © 2010 Stéphane Raimbault <stephane.raimbault@gmail.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser Public License for more details.
*
* You should have received a copy of the GNU Lesser Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _MODBUS_PRIVATE_H_
#define _MODBUS_PRIVATE_H_
#include <sys/time.h>
#include <sys/types.h>
#include <stdint.h>
#include <config.h>
#include "modbus.h"
MODBUS_BEGIN_DECLS
/* It's not really the minimal length (the real one is report slave ID
* in RTU (4 bytes)) but it's a convenient size to use in RTU or TCP
* communications to read many values or write a single one.
* Maximum between :
* - HEADER_LENGTH_TCP (7) + function (1) + address (2) + number (2)
* - HEADER_LENGTH_RTU (1) + function (1) + address (2) + number (2) + CRC (2)
*/
#define _MIN_REQ_LENGTH 12
#define _REPORT_SLAVE_ID_LENGTH 75
#define _MODBUS_EXCEPTION_RSP_LENGTH 5
/* Time out between trames in microsecond */
#define _TIME_OUT_BEGIN_OF_TRAME 500000
#define _TIME_OUT_END_OF_TRAME 500000
/* Function codes */
#define _FC_READ_COILS 0x01
#define _FC_READ_DISCRETE_INPUTS 0x02
#define _FC_READ_HOLDING_REGISTERS 0x03
#define _FC_READ_INPUT_REGISTERS 0x04
#define _FC_WRITE_SINGLE_COIL 0x05
#define _FC_WRITE_SINGLE_REGISTER 0x06
#define _FC_READ_EXCEPTION_STATUS 0x07
#define _FC_WRITE_MULTIPLE_COILS 0x0F
#define _FC_WRITE_MULTIPLE_REGISTERS 0x10
#define _FC_REPORT_SLAVE_ID 0x11
#define _FC_READ_AND_WRITE_REGISTERS 0x17
typedef enum {
_MODBUS_BACKEND_TYPE_RTU=0,
_MODBUS_BACKEND_TYPE_TCP
} modbus_bakend_type_t;
/* This structure reduces the number of params in functions and so
* optimizes the speed of execution (~ 37%). */
typedef struct _sft {
int slave;
int function;
int t_id;
} sft_t;
typedef struct _modbus_backend {
unsigned int backend_type;
unsigned int header_length;
unsigned int checksum_length;
unsigned int max_adu_length;
int (*set_slave) (modbus_t *ctx, int slave);
int (*build_request_basis) (modbus_t *ctx, int function, int addr,
int nb, uint8_t *req);
int (*build_response_basis) (sft_t *sft, uint8_t *rsp);
int (*prepare_response_tid) (const uint8_t *req, int *req_length);
int (*send_msg_pre) (uint8_t *req, int req_length);
ssize_t (*send) (modbus_t *ctx, const uint8_t *req, int req_length);
ssize_t (*recv) (modbus_t *ctx, uint8_t *rsp, int rsp_length);
int (*check_integrity) (modbus_t *ctx, uint8_t *msg,
const int msg_length);
int (*connect) (modbus_t *ctx);
void (*close) (modbus_t *ctx);
int (*flush) (modbus_t *ctx);
int (*select) (modbus_t *ctx, fd_set *rfds, struct timeval *tv, int msg_length_computed, int msg_length);
int (*filter_request) (modbus_t *ctx, int slave);
} modbus_backend_t;
struct _modbus {
/* Slave address */
int slave;
/* Socket or file descriptor */
int s;
int debug;
int error_recovery;
struct timeval timeout_begin;
struct timeval timeout_end;
const modbus_backend_t *backend;
void *backend_data;
};
void _modbus_init_common(modbus_t *ctx);
void _error_print(modbus_t *ctx, const char *context);
#ifndef HAVE_STRLCPY
size_t strlcpy(char *dest, const char *src, size_t dest_size);
#endif
MODBUS_END_DECLS
#endif /* _MODBUS_PRIVATE_H_ */