tests/bandwidth-server-many-up.c

   1 /*
   2  * Copyright © Stéphane Raimbault <stephane.raimbault@gmail.com>
   3  *
   4  * SPDX-License-Identifier: BSD-3-Clause
   5  */
   6
   7 #include <errno.h>
   8 #include <signal.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <unistd.h>
  13
  14 #include <modbus.h>
  15
  16 #if defined(_WIN32)
  17 #include <ws2tcpip.h>
  18 #else
  19 #include <arpa/inet.h>
  20 #include <netinet/in.h>
  21 #include <sys/select.h>
  22 #include <sys/socket.h>
  23 #endif
  24
  25 #define NB_CONNECTION 5
  26
  27 static modbus_t *ctx = NULL;
  28 static modbus_mapping_t *mb_mapping;
  29
  30 static int server_socket = -1;
  31
  32 static void close_sigint(int dummy)
  33 {
  34     if (server_socket != -1) {
  35         close(server_socket);
  36     }
  37     modbus_free(ctx);
  38     modbus_mapping_free(mb_mapping);
  39
  40     exit(dummy);
  41 }
  42
  43 int main(void)
  44 {
  45     uint8_t query[MODBUS_TCP_MAX_ADU_LENGTH];
  46     int master_socket;
  47     int rc;
  48     fd_set refset;
  49     fd_set rdset;
  50     /* Maximum file descriptor number */
  51     int fdmax;
  52
  53     ctx = modbus_new_tcp("127.0.0.1", 1502);
  54
  55     mb_mapping =
  56         modbus_mapping_new(MODBUS_MAX_READ_BITS, 0, MODBUS_MAX_READ_REGISTERS, 0);
  57     if (mb_mapping == NULL) {
  58         fprintf(stderr, "Failed to allocate the mapping: %s\n", modbus_strerror(errno));
  59         modbus_free(ctx);
  60         return -1;
  61     }
  62
  63     server_socket = modbus_tcp_listen(ctx, NB_CONNECTION);
  64     if (server_socket == -1) {
  65         fprintf(stderr, "Unable to listen TCP connection\n");
  66         modbus_free(ctx);
  67         return -1;
  68     }
  69
  70     signal(SIGINT, close_sigint);
  71
  72     /* Clear the reference set of socket */
  73     FD_ZERO(&refset);
  74     /* Add the server socket */
  75     FD_SET(server_socket, &refset);
  76
  77     /* Keep track of the max file descriptor */
  78     fdmax = server_socket;
  79
  80     for (;;) {
  81         rdset = refset;
  82         if (select(fdmax + 1, &rdset, NULL, NULL, NULL) == -1) {
  83             perror("Server select() failure.");
  84             close_sigint(1);
  85         }
  86
  87         /* Run through the existing connections looking for data to be
  88          * read */
  89         for (master_socket = 0; master_socket <= fdmax; master_socket++) {
  90
  91             if (!FD_ISSET(master_socket, &rdset)) {
  92                 continue;
  93             }
  94
  95             if (master_socket == server_socket) {
  96                 /* A client is asking a new connection */
  97                 socklen_t addrlen;
  98                 struct sockaddr_in clientaddr;
  99                 int newfd;
 100
 101                 /* Handle new connections */
 102                 addrlen = sizeof(clientaddr);
 103                 memset(&clientaddr, 0, sizeof(clientaddr));
 104                 newfd = accept(server_socket, (struct sockaddr *) &clientaddr, &addrlen);
 105                 if (newfd == -1) {
 106                     perror("Server accept() error");
 107                 } else {
 108                     FD_SET(newfd, &refset);
 109
 110                     if (newfd > fdmax) {
 111                         /* Keep track of the maximum */
 112                         fdmax = newfd;
 113                     }
 114                     printf("New connection from %s:%d on socket %d\n",
 115                            inet_ntoa(clientaddr.sin_addr),
 116                            clientaddr.sin_port,
 117                            newfd);
 118                 }
 119             } else {
 120                 modbus_set_socket(ctx, master_socket);
 121                 rc = modbus_receive(ctx, query);
 122                 if (rc > 0) {
 123                     modbus_reply(ctx, query, rc, mb_mapping);
 124                 } else if (rc == -1) {
 125                     /* This example server in ended on connection closing or
 126                      * any errors. */
 127                     printf("Connection closed on socket %d\n", master_socket);
 128                     close(master_socket);
 129
 130                     /* Remove from reference set */
 131                     FD_CLR(master_socket, &refset);
 132
 133                     if (master_socket == fdmax) {
 134                         fdmax--;
 135                     }
 136                 }
 137             }
 138         }
 139     }
 140
 141     return 0;
 142 }