#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#define SERVERHOST "f9rt01"

/*
void init_sockaddr (name, hostname, port)
struct sockaddr_in *name;
char *hostname;
unsigned short int port;
{
  struct hostent *hostinfo;
  name->sin_family = AF_INET;
  name->sin_port = htons (port);
  hostinfo = gethostbyname (SERVERHOST); 
  if (hostinfo == NULL)
  {
    fprintf (stderr, "Unknown host %s. \n", hostname);
    exit (EXIT_FAILURE);
  }
  name->sin_addr = *(struct in_addr *) hostinfo->h_addr;
}
*/

/*
**- SUBROUTINE CONNECT_RT(SOCK_NUM)
*/
void connect_rt_ (sock_num)
int *sock_num;
{
  int sock, status;
  unsigned short int port;
  char cmd;
  struct sockaddr_in servername;

  port = (unsigned short int) *sock_num;
  /* Create the socket */
  sock = socket (AF_INET, SOCK_STREAM, 0);
  if (sock < 0)
  {
    perror ("socket (client)");
    exit (EXIT_FAILURE);
  }
  /* Connect to the server */
  init_sockaddr (&servername, SERVERHOST, port);
  if (0 > connect (sock, (struct sockaddr *) &servername,
                   sizeof (servername)))
  {
    perror ("connect (client)");
    exit (EXIT_FAILURE);
  }
  status = recv (sock, &cmd, 1, 0);
  if (cmd != 1)
  {  
    close (sock);
    fprintf (stderr, "RT busy\n%d", status);
    exit (EXIT_FAILURE);
  }
  *sock_num = sock;
}

/*
**- SUBROUTINE SEND_RT(SOCK_NUM,BUFF,LEN)
*/
void send_rt_ (sock_num, buff, len)
int *sock_num, *len;
char *buff;
{
  int status, clen;

  clen = *len;
  do
  {
    if (0 > (status = write (*sock_num, buff, clen)))
    {
      perror ("\nwrite(send_rt)");
      exit (EXIT_FAILURE);
    }
    clen -= status;
    buff += status;
  }
  while (clen);
}

/*
**- SUBROUTINE RECV_RT(SOCK_NUM,BUFF,LEN)
*/
void recv_rt_ (sock_num, buff, len)
int *sock_num, *len;
char *buff;
{
  int status, clen;

  clen = *len;
  do
  {
    if (0 > (status = read (*sock_num, buff, clen)))
    {
      perror ("\nread(recv_rt)");
      exit (EXIT_FAILURE);
    }
    clen -= status;
    buff += status;
  }
  while (clen);
}

/*
**- SUBROUTINE DISCONNECT_RT(SOCK_NUM)
*/
void disconnect_rt_ (sock_num)
int *sock_num;
{
  int status;
  char cmd = 0;
  status = send (*sock_num, &cmd, 1, 0);
  close (*sock_num);
}