3rdparty/libmodbus/modbus-private.h

#pragma once
# include <stdint.h>
# include <sys/time.h>
#include <sys/types.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 180
#define _MODBUS_EXCEPTION_RSP_LENGTH 5
/* Timeouts in microsecond (0.5 s) */
#define _RESPONSE_TIMEOUT    500000
#define _BYTE_TIMEOUT        500000
typedef enum 
{
    _MODBUS_BACKEND_TYPE_RTU=0,
    _MODBUS_BACKEND_TYPE_TCP
} modbus_backend_type_t;
/*
 *  ---------- Request     Indication ----------
 *  | Client | ---------------------->| Server |
 *  ---------- Confirmation  Response ----------
 */
typedef enum 
{
    /* Request message on the server side */
    MSG_INDICATION,
    /* Request message on the client side */
    MSG_CONFIRMATION
} msg_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);
    int (*receive) (modbus_t *ctx, uint8_t *req);
    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 (*pre_check_confirmation) (modbus_t *ctx, const uint8_t *req, const uint8_t *rsp, int rsp_length);
    int (*connect) (modbus_t *ctx);
    void (*close) (modbus_t *ctx);
    int (*flush) (modbus_t *ctx);
    int (*select) (modbus_t *ctx, fd_set *rset, struct timeval *tv, int msg_length);
    void (*free) (modbus_t *ctx);
} modbus_backend_t;
struct _modbus 
{
    /* Slave address */
    int slave;
    /* Socket or file descriptor */
    int s;
    int debug;
    int error_recovery;
    struct timeval response_timeout;
    struct timeval byte_timeout;
    const modbus_backend_t *backend;
    void *backend_data;
};
void _modbus_init_common(modbus_t *ctx);
void _error_print(modbus_t *ctx, const char *context);
int _modbus_receive_msg(modbus_t *ctx, uint8_t *msg, msg_type_t msg_type);
#ifndef HAVE_STRLCPY
size_t strlcpy(char *dest, const char *src, size_t dest_size);
#endif
MODBUS_END_DECLS