connect_nonb

programming/C_C++ 2010. 9. 10. 11:30

int connect_nonb(int sockfd, const struct sockaddr *saptr, socklen_t salen, int nsec)
{
int    flags, status, error;
socklen_t  len;
fd_set    rset, wset;
struct timeval tval;
int fd_max;

flags = fcntl(sockfd, F_GETFL, 0);

if (fcntl(sockfd, F_SETFL, flags | O_NONBLOCK) < 0)
{
  printf("[Error] Non block mode set fail !\n");
  return -1;
}

error = 0;

printf("[INFO] connect function load\n");

status = connect(sockfd, (struct sockaddr *)saptr, salen);

if ((status < 0) && (error == EINPROGRESS))
{
  printf("[INFO] connection fail !!\n");
  return(-1);
}

/* Do whatever we want while the connect is taking place. */

if (status == 0)
  goto done; /* connect completed immediately */

FD_ZERO (&rset);
FD_SET (sockfd, &rset);
wset = rset;

tval.tv_sec = nsec;
tval.tv_usec = 0;

printf("[INFO] select function load\n");

if ((status = select(sockfd + 1, &rset, &wset, NULL, nsec ? & tval : NULL)) == 0) {
  printf("[INFO] select return time out\n");
  close(sockfd);
  error = ETIMEDOUT;
  return (-1);
}

if (FD_ISSET(sockfd, &rset) || FD_ISSET(sockfd, &wset)) {
  len = sizeof(error);
  if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &error, &len) < 0)
   return (-1);
} else {
  printf("[Error] select error: sockfd not set\n");
  return (-1);
}

done:

fcntl(sockfd, F_SETFL, flags); /* restore file status flags */

if (error) {
  printf("[Error] socket error\n");
  close(sockfd);  /* just in case */
  return(-1);
}
printf("[Info] nonb connection complete !! \n");
return(0);
}