1 /* SimpleEchoTCPServer.c
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 echo service (port 7)
24 * Author: Simone Piccardi
29 * $Id: SimpleEchoTCPServer.c,v 1.5 2002/12/03 11:06:05 piccardi Exp $
31 ****************************************************************/
33 * Include needed headers
35 #include <sys/types.h> /* predefined types */
36 #include <unistd.h> /* include unix standard library */
37 #include <arpa/inet.h> /* IP addresses conversion utiliites */
38 #include <sys/socket.h> /* socket library */
39 #include <stdio.h> /* include standard I/O library */
45 /* Subroutines declaration */
47 void SockEcho(int sockfd);
48 /* Program beginning */
49 int main(int argc, char *argv[])
52 * Variables definition
56 struct sockaddr_in serv_add;
58 * Input section: decode parameters passed in the calling
62 opterr = 0; /* don't want writing to stderr */
63 while ( (i = getopt(argc, argv, "h")) != -1) {
69 printf("Wrong -h option use\n");
73 case '?': /* unrecognized options */
74 printf("Unrecognized options -%c\n",optopt);
76 default: /* should not reached */
80 /* ***********************************************************
82 * Options processing completed
86 * ***********************************************************/
88 if ( (list_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
89 perror("Socket creation error");
92 /* initialize address */
93 memset((void *)&serv_add, 0, sizeof(serv_add)); /* clear server address */
94 serv_add.sin_family = AF_INET; /* address type is INET */
95 serv_add.sin_port = htons(7); /* echo port is 7 */
96 serv_add.sin_addr.s_addr = htonl(INADDR_ANY); /* connect from anywhere */
98 if (bind(list_fd, (struct sockaddr *)&serv_add, sizeof(serv_add)) < 0) {
102 /* listen on socket */
103 if (listen(list_fd, BACKLOG) < 0 ) {
104 perror("listen error");
107 /* handle echo to client */
109 /* accept connection */
110 if ( (conn_fd = accept(list_fd, NULL, NULL)) < 0) {
111 perror("accept error");
114 /* fork to handle connection */
115 if ( (pid = fork()) < 0 ){
116 perror("fork error");
119 if (pid == 0) { /* child */
120 close(list_fd); /* close listening socket */
121 SockEcho(conn_fd); /* handle echo */
123 } else { /* parent */
124 close(conn_fd); /* close connected socket */
127 /* normal exit, never reached */
131 * routine to print usage info and exit
134 printf("Simple daytime server\n");
136 printf(" daytimed [-h] \n");
137 printf(" -h print this help\n");
141 * routine to handle echo for connection
143 void SockEcho(int sockfd) {
144 char buffer[MAXLINE];
147 /* main loop, reading 0 char means client close connection */
148 while ( (nread = read(sockfd, buffer, MAXLINE)) != 0) {
149 printf("Letti %d bytes, %s ", nread, buffer);
150 nwrite = SockWrite(sockfd, buffer, nread);