tests/bandwidth-server-many-up.c

   1 /*
   2  * Copyright © 2009-2010 Stéphane Raimbault <stephane.raimbault@gmail.com>
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <stdio.h>
  19 #include <unistd.h>
  20 #include <string.h>
  21 #include <stdlib.h>
  22 #include <errno.h>
  23 #include <signal.h>
  24
  25 #include <modbus.h>
  26
  27 #if defined(_WIN32)
  28 #include <ws2tcpip.h>
  29 #else
  30 #include <sys/socket.h>
  31 #include <netinet/in.h>
  32 #include <arpa/inet.h>
  33 #endif
  34
  35 #define NB_CONNECTION    5
  36
  37 modbus_t *ctx = NULL;
  38 int server_socket;
  39 modbus_mapping_t *mb_mapping;
  40
  41 static void close_sigint(int dummy)
  42 {
  43     close(server_socket);
  44     modbus_free(ctx);
  45     modbus_mapping_free(mb_mapping);
  46
  47     exit(dummy);
  48 }
  49
  50 int main(void)
  51 {
  52     int master_socket;
  53     int rc;
  54     fd_set refset;
  55     fd_set rdset;
  56
  57     /* Maximum file descriptor number */
  58     int fdmax;
  59
  60     ctx = modbus_new_tcp("127.0.0.1", 1502);
  61
  62     mb_mapping = modbus_mapping_new(MODBUS_MAX_READ_BITS, 0,
  63                                     MODBUS_MAX_READ_REGISTERS, 0);
  64     if (mb_mapping == NULL) {
  65         fprintf(stderr, "Failed to allocate the mapping: %s\n",
  66                 modbus_strerror(errno));
  67         modbus_free(ctx);
  68         return -1;
  69     }
  70
  71     server_socket = modbus_tcp_listen(ctx, NB_CONNECTION);
  72
  73     signal(SIGINT, close_sigint);
  74
  75     /* Clear the reference set of socket */
  76     FD_ZERO(&refset);
  77     /* Add the server socket */
  78     FD_SET(server_socket, &refset);
  79
  80     /* Keep track of the max file descriptor */
  81     fdmax = server_socket;
  82
  83     for (;;) {
  84         rdset = refset;
  85         if (select(fdmax+1, &rdset, NULL, NULL, NULL) == -1) {
  86             perror("Server select() failure.");
  87             close_sigint(1);
  88         }
  89
  90         /* Run through the existing connections looking for data to be
  91          * read */
  92         for (master_socket = 0; master_socket <= fdmax; master_socket++) {
  93
  94             if (FD_ISSET(master_socket, &rdset)) {
  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), clientaddr.sin_port, newfd);
 116                     }
 117                 } else {
 118                     /* An already connected master has sent a new query */
 119                     uint8_t query[MODBUS_TCP_MAX_ADU_LENGTH];
 120
 121                     rc = modbus_receive_from(ctx, master_socket, query);
 122                     if (rc != -1) {
 123                         modbus_reply(ctx, query, rc, mb_mapping);
 124                     } else {
 125                         /* Connection closed by the client, end of server */
 126                         printf("Connection closed on socket %d\n", master_socket);
 127                         close(master_socket);
 128
 129                         /* Remove from reference set */
 130                         FD_CLR(master_socket, &refset);
 131
 132                         if (master_socket == fdmax) {
 133                             fdmax--;
 134                         }
 135                     }
 136                 }
 137             }
 138         }
 139     }
 140
 141     return 0;
 142 }