/*********** F_TCP.C ********/
#include <stdio.h>
#include <stdlib.h>
#include "f_tcp.h"
#include <signal.h>



/*******************************************************************/
int config_tcp_port_client(int *pfd) /* in output file descriptor */
{
  int sk;
  
  if ((sk = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
      perror("Configuring TCP socket failed");
      return(-1);
  }
  *pfd = sk;
  return(0);
}

/*******************************************************************/
int config_tcp_port_server(
			   int serv_addr,	/* input, address desired */
			   int *pfd)	/* output, file descriptor */
{
  struct sockaddr_in server;
  int sk, len, optval;
  
  if ((sk = socket(AF_INET, SOCK_STREAM, 0)) == -1) 
    {
      perror("Configuring TCP socket failed");
      return(-1);
    }
  *pfd = sk;
  optval = 1;
  
  if (setsockopt(sk,SOL_SOCKET,SO_REUSEADDR,(char *)&optval,
		 sizeof(int)) == -1) 
    {
      perror("Configuring TCP socket options failed");
      return(-1);
    }
  
  server.sin_family = AF_INET;
  server.sin_addr.s_addr = INADDR_ANY;
  server.sin_port = htons((unsigned short)serv_addr);
  if (bind (sk, (struct sockaddr *)&server, sizeof(server)) == -1) 
    {
      perror("Binding TCP socket failed");
      return(-1);
    }
  len = sizeof(server);
  if (getsockname(sk, (struct sockaddr *)&server, &len) == -1) 
    {
      perror("TCP getsockname function failed"); 
      return(-1);
    }
  if (server.sin_port != htons((unsigned short)serv_addr)) 
    {
      printf("Wrong TCP socket address assigned");
      return(-1);
    }
  return(0);
}

/*******************************************************************/
void unconfig_tcp_port(int fd)
{
  ioctl(fd, I_FLUSH, FLUSHRW);
  if (shutdown(fd, 2) == -1)
    perror("Shutdown failed");
  if (close(fd) == -1)
    perror("Close failed");
}

/*******************************************************************/
void tcp_port_sign(int fd)
{
  ioctl(fd, I_SETSIG, S_INPUT /*| S_ERROR*/ );
}

/*******************************************************************/
int cl_to_ser_connection(
			 char 	*server_name,	        /* input */
			 int 		serv_addr,    	/* input */
			 int 		sk)		/* input */
{
  struct sockaddr_in server;
  struct hostent *hp;
  int fileflags;
  
  server.sin_family = AF_INET;
  if ((hp = gethostbyname(server_name)) == (struct hostent *)NULL) 
    {
      perror("Gethostbyname failed");
      return(-1);
    }
  memcpy((char *)&server.sin_addr, (char *)hp->h_addr, hp->h_length);
  server.sin_port = htons((unsigned short)serv_addr);
  if (connect(sk, (struct sockaddr *)&server, sizeof(server)) == -1) 
    {
      perror("Connect failed");
      return(-1);
    }
  if ((fileflags = fcntl(sk, F_GETFL, 0)) == -1) 
    {
      perror("Fcntl F_GETFL failed");
      return(-1);
    }
  if (fcntl(sk, F_SETFL, fileflags | /*FNDELAY |*/ FASYNC ) == -1) 
    {
      perror("Fcntl F_SETFL failed");
      return(-1);
    }
  printf("TCP socket connection established\n");
  return(1);
}

/*******************************************************************/
int ser_to_cl_connection (int fd, int * pmsgsock, pid_t * childproc_num)
{
  int fileflags;
  pid_t forkres;
  int ww;
  int *wstat;

  wstat = &ww;
  listen(fd, SOMAXCONN);  
  for (;;) 
    {
      *pmsgsock = accept (fd, (struct sockaddr *)0, (int *)0);
      if (*pmsgsock == -1) 
	{
	  perror("Accept failed");
	  exit(0);
	} 
      else 
	{
	  if (*childproc_num) 
	    {
	      kill(*childproc_num, SIGTERM);
	      wait(wstat);
	      *childproc_num = 0;
	    }
	  forkres = fork();
	  switch (forkres) 
	    {
	    case -1:
	      perror("Fork failed");
	      sleep(1);
	      exit(1);
	      break;
	    case 0: /*child*/
	      if ((fileflags = fcntl(*pmsgsock, F_GETFL, 0)) == -1) 
		{
		  perror("Fcntl F_GETFL failed");
		  return(-1);
		}
	      if (fcntl(*pmsgsock, F_SETFL, 
			fileflags/*|FNDELAY*/|FASYNC) == -1) 
		{
		  perror("Fcntl F_SETFL failed");
		  return(-1);
		}
	      /* go back to the calling process that can 
		 start to tx/rx with send and recv */
	      return(1);
	    default:
	      *childproc_num = forkres;
	      break;
	    } /*switch()*/
	} /*if()...else...*/
    } /*for(;;)*/
} /* ser_to_cl_connection()*/