3 * Copyright (C) 2004 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 */
43 int main(int argc, char *argv[])
46 * Variables definition
49 int i, n, len, verbose=0;
50 struct sockaddr_in addr;
54 * Input section: decode parameters passed in the calling
57 opterr = 0; /* don't want writing to stderr */
58 while ( (i = getopt(argc, argv, "hv")) != -1) {
64 printf("Wrong -h option use\n");
71 case '?': /* unrecognized options */
72 printf("Unrecognized options -%c\n",optopt);
74 default: /* should not reached */
78 /* ***********************************************************
80 * Options processing completed
84 * ***********************************************************/
86 if ( (sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
87 perror("Socket creation error");
90 /* initialize address */
91 memset((void *)&addr, 0, sizeof(addr)); /* clear server address */
92 addr.sin_family = AF_INET; /* address type is INET */
93 addr.sin_port = htons(13); /* daytime port is 13 */
94 addr.sin_addr.s_addr = htonl(INADDR_ANY); /* connect from anywhere */
96 if (bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
100 /* write daytime to client */
102 n = recvfrom(sock, buffer, MAXLINE, 0, (struct sockaddr *)&addr, &len);
104 perror("recvfrom error");
108 inet_ntop(AF_INET, &addr.sin_addr, buffer, sizeof(buffer));
109 printf("Request from host %s, port %d\n", buffer,
110 ntohs(addr.sin_port));
112 timeval = time(NULL);
113 snprintf(buffer, sizeof(buffer), "%.24s\r\n", ctime(&timeval));
114 n = sendto(sock, buffer, strlen(buffer), 0,
115 (struct sockaddr *)&addr, sizeof(addr));
117 perror("sendto error");
125 * routine to print usage info and exit
128 printf("Simple daytime server\n");
130 printf(" daytimed [-hv] \n");
131 printf(" -h print this help\n");
132 printf(" -v print request source on stdout\n");