tcpip10.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#define BUF_SIZE 1024
void error_handling(char * message);
int main(int argc, char * argv[])
{
	int serv_sock, clnt_sock;
	char message[BUF_SIZE];
	int str_len, i;

	struct sockaddr_in serv_adr;
	struct sockaddr_in clnt_adr;
	socklen_t clnt_adr_sz;

	if(argc!=2)
	{
		printf("Usage:%s<port>\n", argv[0]);
		exit(1);
	}

	serv_sock=socket(PF_INET,SOCK_STREAM,0);
	if(serv_sock==-1)
	error_handling("socket() error");

	memset(&serv_adr,0,sizeof(serv_adr));
	serv_adr.sin_family=AF_INET;
	serv_adr.sin_addr.s_addr=htonl(INADDR_ANY);
	serv_adr.sin_port=htons(atoi(argv[1]));

	if(bind(serv_sock, (struct sockaddr*)&serv_adr, sizeof(serv_adr))==-1)
		error_handling("bind() error");

	if(listen(serv_sock,5)==-1)
		error_handling("listen() error");

	clnt_adr_sz=sizeof(clnt_adr);

	for(i=0;i<5;i++)
	{
		clnt_sock=accept(serv_sock, (struct sockaddr*)&clnt_adr, &clnt_adr_sz);
		if(clnt_sock==-1)
			error_handling("accept() error");
		else
			printf("Connected client %d\n", i+1);
		
		while((str_len=read(clnt_sock, message, BUF_SIZE))!=0)
			write(clnt_sock,message,str_len);
		close(clnt_sock);
	}
	close(serv_sock);
	return 0;
}

void error_handling(char * message)
{
	fputs(message,stderr);
	fputc('\n',stderr);
	exit(1);
}