1 /*

     2  * Copyright (c) 2002,2016 Mario de Sousa (msousa@fe.up.pt)

     3  *

     4  * This file is part of the Modbus library for Beremiz and matiec.

     5  *

     6  * This Modbus library is free software: you can redistribute it and/or modify

     7  * it under the terms of the GNU Lesser General Public License as published by

     8  * the Free Software Foundation, either version 3 of the License, or

     9  * (at your option) any later version.

    10  *

    11  * This program is distributed in the hope that it will be useful, but

    12  * WITHOUT ANY WARRANTY; without even the implied warranty of

    13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser 

    14  * General Public License for more details.

    15  *

    16  * You should have received a copy of the GNU Lesser General Public License

    17  * along with this Modbus library.  If not, see <http://www.gnu.org/licenses/>.

    18  *

    19  * This code is made available on the understanding that it will not be

    20  * used in safety-critical situations without a full and competent review.

    21  */

    22 

    23 

    24 

    25 #ifndef MODBUS_TCP_PRIVATE_H

    26 #define MODBUS_TCP_PRIVATE_H

    27 

    28 

    29 #include "mb_util.h"

    30 

    31 

    32 /* tcp port default configuration... */

    33 #define DEF_SERVICE  "502"        /* port used by modbus */

    34 #define DEF_PROTOCOL "tcp"        /* protocol used by modbus tcp */

    35 #define DEF_TYPE     SOCK_STREAM  /* Quality of service required of the socket... */

    36 #define DEF_MAX_PENDING_CONNECTION_REQUESTS 5

    37                                   /* maximum number of pending connection requests

    38                                    * that have not yet been accept()'ed

    39                                    */

    40 #define DEF_CLOSE_ON_SILENCE 1    /* Used only by master nodes.

    41                                    * Flag indicating whether, by default, the connection

    42                                    * to the slave device should be closed whenever the

    43                                    * modbus_tcp_silence_init() function is called.

    44                                    *

    45                                    * 0  -> do not close connection

    46                                    * >0 -> close connection

    47                                    *

    48                                    * The spec sugests that connections that will not

    49                                    * be used for longer than 1 second should be closed.

    50                                    * Even though we expect most connections to have

    51                                    * silence intervals much shorted than 1 second, we

    52                                    * decide to use the default of shuting down the

    53                                    * connections because it is safer, and most other

    54                                    * implementations seem to do the same.

    55                                    * If we do not close we risk using up all the possible

    56                                    * connections that the slave can simultaneouly handle,

    57                                    * effectively locking out every other master that

    58                                    * wishes to communicate with that same slave.

    59                                    */

    60 

    61  /* Since the receive buffer is also re-used to store the frame header,

    62   * we set it to the larger of the two.

    63   */

    64 #if     TCP_HEADER_LENGTH > MAX_L2_FRAME_LENGTH

    65 #define RECV_BUFFER_SIZE    TCP_HEADER_LENGTH

    66 #else

    67 #define RECV_BUFFER_SIZE    MAX_L2_FRAME_LENGTH

    68 #endif

    69 

    70 

    71 

    72 

    73 #endif  /* MODBUS_TCP_PRIVATE_H */

    74 

    75 

    76 

    77 

    78 

    79 

    80 

    81