Server.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
int_GetHostName (char *buffer, int length);
const char MESSAGE[ ]=”Hello, World!\n”;
const int BACK_LOG=5;
int main(int argc, char *argv[ ]) {
int serverSocket=0, on=0, port=0, status=0, childPid=0;
struct hostent *hostPtr=NULL;
char hostname[80]=””;
struct sockaddr_in serverName={0};
if (2!=argc) {
fprintf (stderr, “Usage: %s <port>\n”, argv[0]);
exit(1);
}
port=atoi(argv[1]);
serverSocket=socket(PF_INET,SOCK_STREAM,IPPROTO_TC P);
if (-1==serverSocket){
perror(“socket()”);
exit(1);
}
/* turn off bind address checking, and allow port numbers
* to be reused – otherwise the TIME_WAIT phenomenon will
* prevent binding to these address.port combinations for
* (2 * MSL) seconds.
*/
on=1;
status=setsockopt (serverSocket, SOL_SOCKET, SO_REUSEADDR,
(const char*)&on, sizeof (on));
If (-1==status) {
perror (“setsockopt(…,SO_REUSEADDR,…)”);
}
/* when connection is closed, there is a need to linger to ensure
* all data is transmitted, so turn this on also
*/
{
struct linger linger={0};
linger.l_onoff=1;
linger.l_linger=30;
status=setsockopt(serverSocket,SOL_SOCKET,SO_LINGE R,
(const char*)&linger,sizeof(linger));
if(-1==status) {
perror (“setsockopt(…SO_LINGER,…)”);
}
}
/* dito ang di ko alam kung
* ano ang ilalagay
*/
status=_GetHostName(hostname,sizeof(hostname));
if(-1==status) {
perror(“_GetHostName( )”);
exit(1);
}
hostPtr=gethostbyname(hostname);
if(NULL==hostPtr) {
perror(“gethostbyname( )”);
exit(1);
}
(void)memset(&serverName, 0, sizeof (serverName));
(void)memcpy(&serverName.sin_addr,hostPtr->h_addr,hostPtr->h_length);
/*to allow server be contactable on any of its
*IP addresses, uncomment the following line of code:
*
*serverName.sin_addr.s_addr = htonl (INADDR_ANY);
*/
serverName.sin_family=AF_INET;
serverName.sin_port=htons(port); /* network-order */
status=bind(serverSocket, (struct sockaddr*)&serverName, sizeof(serverName));
if(-1==status) {
perror(“bind( )”);
exit(1);
}
status=listen(serverSocket,BACK_LOG);
if(-1==status) {
perror(“listen( )”);
exit(1);
}
for(; ; ) {
struct sockaddr_in clientName={0};
int slaveSocket, clientLength=sizeof(clientName);
(void)memset(&clientName,0,sizeof(clientName));
slaveSocket=accept(serverSocket,
(struct sockaddr*)&clientName,&clientLength);
If (-1==slaveSocket) {
perror(“accept( )”);
exit(1);
}
childPid=fork( );
switch (childPid) {
case -1 : /*MY error */
perror(“fork( )”);
exit(1);
case 0 : /*child process */
close(serverSocket);
if (-1==getpeername(slaveSocket,
(struct sockaddr*)&clientName,&clientLength)) {
perror(“getpeername( )”);
} else {
printf(“Connection request from %s \n”,
inet_ntoa (clientName.sin_addr));
}
/*
*Server application specific code must goes here
*e.g perform some action, respond to client etc.
* pero di ko alam kung ano ilalagay
*/
write(slaveSocket,MESSAGE,strlen(MESSAGE));
close(slaveSocket);
exit(0);
default : /*parent process */
close(slaveSocket);
}
}
return 0;
}
/*Local replacement of gethostname( ) to aid portability
*/
int_GetHostName(char *buffer, int length) {
struct utsname sysname={0};
int status=0;
status=uname(&sysname);
if(-1!=status) {
strncpy(buffer,sysname.nodename,length);
}
return(status);
}
paki ayos man po ng codes ko using C language sa networking
[/RED]
kain muna may pasok pa ako ngay0n. . . 
always nlang umuulan.
