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 client for daytime service (port 13)
24 * Author: Simone Piccardi
27 * Usage: daytime -h give all info's
29 ****************************************************************/
31 * Include needed headers
33 #include <stdlib.h> /* standard library */
34 #include <sys/types.h> /* primitive system data types */
35 #include <unistd.h> /* unix standard library */
36 #include <arpa/inet.h> /* IP addresses conversion utilities */
37 #include <sys/socket.h> /* socket constants, types and functions */
38 #include <stdio.h> /* standard I/O library */
43 int main(int argc, char *argv[])
46 * Variables definition
50 struct sockaddr_in serv_add;
53 * Input section: decode parameters passed in the calling
56 opterr = 0; /* don't want writing to stderr */
57 while ( (i = getopt(argc, argv, "h")) != -1) {
63 printf("Wrong -h option use\n");
67 case '?': /* unrecognized options */
68 printf("Unrecognized options -%c\n",optopt);
70 default: /* should not reached */
74 /* ***********************************************************
76 * Options processing completed
80 * ***********************************************************/
82 if ( (sock_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
83 perror("Socket creation error");
86 /* initialize address */
87 memset((void *) &serv_add, 0, sizeof(serv_add)); /* clear server address */
88 serv_add.sin_family = AF_INET; /* address type is INET */
89 serv_add.sin_port = htons(13); /* daytime port is 13 */
90 /* build address using inet_pton */
91 if ( (inet_pton(AF_INET, argv[optind], &serv_add.sin_addr)) <= 0) {
92 perror("Address creation error");
95 /* extablish connection */
96 if (connect(sock_fd, (struct sockaddr *)&serv_add, sizeof(serv_add)) < 0) {
97 perror("Connection error");
100 /* read daytime from server */
101 while ( (nread = read(sock_fd, buffer, MAXLINE)) > 0) {
103 if (fputs(buffer, stdout) == EOF) { /* write daytime */
104 perror("fputs error");
110 perror("Read error");
117 * routine to print usage info and exit
120 printf("Take daytime from a remote host \n");
122 printf(" daytime [-h] [-v] [host in dotted decimal form] \n");
123 // printf(" -v set verbosity on\n");
124 printf(" -h print this help\n");