src/modbus-private.h

   1 /*
   2  * Copyright © 2010-2012 Stéphane Raimbault <stephane.raimbault@gmail.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-or-later
   5  */
   6
   7 #ifndef MODBUS_PRIVATE_H
   8 #define MODBUS_PRIVATE_H
   9
  10 #ifndef _MSC_VER
  11 # include <stdint.h>
  12 # include <sys/time.h>
  13 #else
  14 # include "stdint.h"
  15 # include <time.h>
  16 typedef int ssize_t;
  17 #endif
  18 #include <sys/types.h>
  19 #include <config.h>
  20
  21 #include "modbus.h"
  22
  23 MODBUS_BEGIN_DECLS
  24
  25 /* It's not really the minimal length (the real one is report slave ID
  26  * in RTU (4 bytes)) but it's a convenient size to use in RTU or TCP
  27  * communications to read many values or write a single one.
  28  * Maximum between :
  29  * - HEADER_LENGTH_TCP (7) + function (1) + address (2) + number (2)
  30  * - HEADER_LENGTH_RTU (1) + function (1) + address (2) + number (2) + CRC (2)
  31  */
  32 #define _MIN_REQ_LENGTH 12
  33
  34 #define _REPORT_SLAVE_ID 180
  35
  36 #define _MODBUS_EXCEPTION_RSP_LENGTH 5
  37
  38 /* Timeouts in microsecond (0.5 s) */
  39 #define _RESPONSE_TIMEOUT    500000
  40 #define _BYTE_TIMEOUT        500000
  41
  42 typedef enum {
  43     _MODBUS_BACKEND_TYPE_RTU=0,
  44     _MODBUS_BACKEND_TYPE_TCP
  45 } modbus_backend_type_t;
  46
  47 /*
  48  *  ---------- Request     Indication ----------
  49  *  | Client | ---------------------->| Server |
  50  *  ---------- Confirmation  Response ----------
  51  */
  52 typedef enum {
  53     /* Request message on the server side */
  54     MSG_INDICATION,
  55     /* Request message on the client side */
  56     MSG_CONFIRMATION
  57 } msg_type_t;
  58
  59 /* This structure reduces the number of params in functions and so
  60  * optimizes the speed of execution (~ 37%). */
  61 typedef struct _sft {
  62     int slave;
  63     int function;
  64     int t_id;
  65 } sft_t;
  66
  67 typedef struct _modbus_backend {
  68     unsigned int backend_type;
  69     unsigned int header_length;
  70     unsigned int checksum_length;
  71     unsigned int max_adu_length;
  72     int (*set_slave) (modbus_t *ctx, int slave);
  73     int (*build_request_basis) (modbus_t *ctx, int function, int addr,
  74                                 int nb, uint8_t *req);
  75     int (*build_response_basis) (sft_t *sft, uint8_t *rsp);
  76     int (*prepare_response_tid) (const uint8_t *req, int *req_length);
  77     int (*send_msg_pre) (uint8_t *req, int req_length);
  78     ssize_t (*send) (modbus_t *ctx, const uint8_t *req, int req_length);
  79     int (*receive) (modbus_t *ctx, uint8_t *req);
  80     ssize_t (*recv) (modbus_t *ctx, uint8_t *rsp, int rsp_length);
  81     int (*check_integrity) (modbus_t *ctx, uint8_t *msg,
  82                             const int msg_length);
  83     int (*pre_check_confirmation) (modbus_t *ctx, const uint8_t *req,
  84                                    const uint8_t *rsp, int rsp_length);
  85     int (*connect) (modbus_t *ctx);
  86     void (*close) (modbus_t *ctx);
  87     int (*flush) (modbus_t *ctx);
  88     int (*select) (modbus_t *ctx, fd_set *rset, struct timeval *tv, int msg_length);
  89     void (*free) (modbus_t *ctx);
  90 } modbus_backend_t;
  91
  92 struct _modbus {
  93     /* Slave address */
  94     int slave;
  95     /* Socket or file descriptor */
  96     int s;
  97     int debug;
  98     int error_recovery;
  99     struct timeval response_timeout;
 100     struct timeval byte_timeout;
 101     struct timeval indication_timeout;
 102     const modbus_backend_t *backend;
 103     void *backend_data;
 104 };
 105
 106 void _modbus_init_common(modbus_t *ctx);
 107 void _error_print(modbus_t *ctx, const char *context);
 108 int _modbus_receive_msg(modbus_t *ctx, uint8_t *msg, msg_type_t msg_type);
 109
 110 #ifndef HAVE_STRLCPY
 111 size_t strlcpy(char *dest, const char *src, size_t dest_size);
 112 #endif
 113
 114 MODBUS_END_DECLS
 115
 116 #endif  /* MODBUS_PRIVATE_H */