src/modbus-tcp-private.h

   1 /*
   2  * Copyright © Stéphane Raimbault <stephane.raimbault@gmail.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-or-later
   5  */
   6
   7 #ifndef MODBUS_TCP_PRIVATE_H
   8 #define MODBUS_TCP_PRIVATE_H
   9
  10 #define _MODBUS_TCP_HEADER_LENGTH     7
  11 #define _MODBUS_TCP_PRESET_REQ_LENGTH 12
  12 #define _MODBUS_TCP_PRESET_RSP_LENGTH 8
  13
  14 #define _MODBUS_TCP_CHECKSUM_LENGTH 0
  15
  16 /* In both structures, the transaction ID must be placed on first position
  17    to have a quick access not dependent of the TCP backend */
  18 typedef struct _modbus_tcp {
  19     /* Extract from MODBUS Messaging on TCP/IP Implementation Guide V1.0b
  20        (page 23/46):
  21        The transaction identifier is used to associate the future response
  22        with the request. This identifier is unique on each TCP connection. */
  23     uint16_t t_id;
  24     /* TCP port */
  25     int port;
  26     /* IP address */
  27     char ip[16];
  28 } modbus_tcp_t;
  29
  30 typedef struct _modbus_tcp_pi {
  31     /* Transaction ID */
  32     uint16_t t_id;
  33     /* TCP port */
  34     int port;
  35     /* Node */
  36     char *node;
  37     /* Service */
  38     char *service;
  39 } modbus_tcp_pi_t;
  40
  41 #endif /* MODBUS_TCP_PRIVATE_H */