3 * Copyright (C) 2001 Simone Piccardi
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or (at
8 * your option) any later version.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 /****************************************************************
22 * Elementary TCP server for daytime service (port 13)
24 * Author: Simone Piccardi
27 * Usage: daytimed -h give all info
29 ****************************************************************/
31 * Include needed headers
33 #include <sys/types.h> /* primitive system data types */
34 #include <unistd.h> /* unix standard library */
35 #include <arpa/inet.h> /* IP addresses conversion utilities */
36 #include <sys/socket.h> /* socket constants, types and functions */
37 #include <stdio.h> /* standard I/O library */
38 #include <time.h> /* date and time constants, types and functions */
44 int main(int argc, char *argv[])
47 * Variables definition
51 struct sockaddr_in serv_add;
55 * Input section: decode parameters passed in the calling
58 opterr = 0; /* don't want writing to stderr */
59 while ( (i = getopt(argc, argv, "h")) != -1) {
65 printf("Wrong -h option use\n");
69 case '?': /* unrecognized options */
70 printf("Unrecognized options -%c\n",optopt);
72 default: /* should not reached */
76 /* ***********************************************************
78 * Options processing completed
82 * ***********************************************************/
84 if ( (list_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
85 perror("Socket creation error");
88 /* initialize address */
89 memset((void *)&serv_add, 0, sizeof(serv_add)); /* clear server address */
90 serv_add.sin_family = AF_INET; /* address type is INET */
91 serv_add.sin_port = htons(13); /* daytime port is 13 */
92 serv_add.sin_addr.s_addr = htonl(INADDR_ANY); /* connect from anywhere */
94 if (bind(list_fd, (struct sockaddr *)&serv_add, sizeof(serv_add)) < 0) {
98 /* listen on socket */
99 if (listen(list_fd, BACKLOG) < 0 ) {
100 perror("listen error");
103 /* write daytime to client */
105 if ( (conn_fd = accept(list_fd, (struct sockaddr *) NULL, NULL)) <0 ) {
106 perror("accept error");
109 timeval = time(NULL);
110 snprintf(buffer, sizeof(buffer), "%.24s\r\n", ctime(&timeval));
111 if ( (write(conn_fd, buffer, strlen(buffer))) < 0 ) {
112 perror("write error");
122 * routine to print usage info and exit
125 printf("Simple daytime server\n");
127 printf(" daytimed [-h] \n");
128 printf(" -h print this help\n");