소켓프로그래밍에서 포트 중계(릴레이)를 구현하고 싶습니다..

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
 
#define BUFSIZE 1024
void error_handling(char *message);
 
int main(int argc, char **argv)
{
 int serv_sock;
 int clnt_sock;
 char message[BUFSIZE];
 int str_len;
 
 struct sockaddr_in serv_addr;
 struct sockaddr_in clnt_addr;
 int clnt_addr_size;
 
 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_addr, 0, sizeof(serv_addr));
 serv_addr.sin_family=AF_INET;
 serv_addr.sin_addr.s_addr=htonl(INADDR_ANY);
 serv_addr.sin_port=htons(atoi(argv[1]));
 
 if(bind(serv_sock, (struct sockaddr*) &serv_addr, sizeof(serv_addr))==-1)
  error_handling("bind() error");
 
 if(listen(serv_sock, 5)==-1)
  error_handling("listen() error");
 
 while( 1 )
 {
    clnt_addr_size=sizeof(clnt_addr);
    clnt_sock=accept(serv_sock, (struct sockaddr*)&clnt_addr,&clnt_addr_size);
     if(clnt_sock==-1)
      error_handling("accept() error");
 
     /* 데이터 수신 및 전송 */
     while( (str_len=read(clnt_sock,message, BUFSIZE)) != 0){
      write(clnt_sock, message, str_len);
      write(1, message, str_len);
     }
     close(clnt_sock);
 }
 return 0;
}
 
void error_handling(char *message)
{
 fputs(message, stderr);
 fputc('\n', stderr);
 exit(1);
}