/* * Copyright © 2009-2010 Stéphane Raimbault * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ #include #include #include #include #include #include #include #if defined(_WIN32) #include #else #include #include #include #endif #define NB_CONNECTION 5 modbus_t *ctx = NULL; int server_socket; modbus_mapping_t *mb_mapping; static void close_sigint(int dummy) { close(server_socket); modbus_free(ctx); modbus_mapping_free(mb_mapping); exit(dummy); } int main(void) { int master_socket; int rc; fd_set refset; fd_set rdset; /* Maximum file descriptor number */ int fdmax; ctx = modbus_new_tcp("127.0.0.1", 1502); mb_mapping = modbus_mapping_new(MODBUS_MAX_READ_BITS, 0, MODBUS_MAX_READ_REGISTERS, 0); if (mb_mapping == NULL) { fprintf(stderr, "Failed to allocate the mapping: %s\n", modbus_strerror(errno)); modbus_free(ctx); return -1; } server_socket = modbus_tcp_listen(ctx, NB_CONNECTION); signal(SIGINT, close_sigint); /* Clear the reference set of socket */ FD_ZERO(&refset); /* Add the server socket */ FD_SET(server_socket, &refset); /* Keep track of the max file descriptor */ fdmax = server_socket; for (;;) { rdset = refset; if (select(fdmax+1, &rdset, NULL, NULL, NULL) == -1) { perror("Server select() failure."); close_sigint(1); } /* Run through the existing connections looking for data to be * read */ for (master_socket = 0; master_socket <= fdmax; master_socket++) { if (FD_ISSET(master_socket, &rdset)) { if (master_socket == server_socket) { /* A client is asking a new connection */ socklen_t addrlen; struct sockaddr_in clientaddr; int newfd; /* Handle new connections */ addrlen = sizeof(clientaddr); memset(&clientaddr, 0, sizeof(clientaddr)); newfd = accept(server_socket, (struct sockaddr *)&clientaddr, &addrlen); if (newfd == -1) { perror("Server accept() error"); } else { FD_SET(newfd, &refset); if (newfd > fdmax) { /* Keep track of the maximum */ fdmax = newfd; } printf("New connection from %s:%d on socket %d\n", inet_ntoa(clientaddr.sin_addr), clientaddr.sin_port, newfd); } } else { /* An already connected master has sent a new query */ uint8_t query[MODBUS_TCP_MAX_ADU_LENGTH]; modbus_set_socket(ctx, master_socket); rc = modbus_receive(ctx, query); if (rc != -1) { modbus_reply(ctx, query, rc, mb_mapping); } else { /* Connection closed by the client, end of server */ printf("Connection closed on socket %d\n", master_socket); close(master_socket); /* Remove from reference set */ FD_CLR(master_socket, &refset); if (master_socket == fdmax) { fdmax--; } } } } } } return 0; } ='#n53'>53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140