src/modbus-tcp-private.h

   1 /*
   2  * Copyright © 2001-2011 Stéphane Raimbault <stephane.raimbault@gmail.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1+
   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 dependant 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 #define _MODBUS_TCP_PI_NODE_LENGTH    1025
  31 #define _MODBUS_TCP_PI_SERVICE_LENGTH   32
  32
  33 typedef struct _modbus_tcp_pi {
  34     /* Transaction ID */
  35     uint16_t t_id;
  36     /* TCP port */
  37     int port;
  38     /* Node */
  39     char node[_MODBUS_TCP_PI_NODE_LENGTH];
  40     /* Service */
  41     char service[_MODBUS_TCP_PI_SERVICE_LENGTH];
  42 } modbus_tcp_pi_t;
  43
  44 #endif /* MODBUS_TCP_PRIVATE_H */