util.c

linux 上端口映射程序源代码

connect_host_to_proxy (int connection, char *remote_host, char *remote_port)
{
  int count;
  char proxy_user[256];
  char User_Agent[256];

  debug_printf (">connect_host_to_proxy(%d,%s,%s)\n", connection, remote_host,
		remote_port);
  debug_printf (">socket(AF_INET,SOCK_STREAM,0)\n");
  if ((proxy_socket[connection] = socket (AF_INET, SOCK_STREAM, 0)) < 0)
    {
      perror ("socket");
      return -1;
    }
  debug_printf ("socket> (%d)\n", proxy_socket[connection]);
  if ((proxy_hostent = gethostbyname (proxy_host)) == NULL)
    {
      switch (h_errno)
	{
	case TRY_AGAIN:
	  {
	    printf ("gethostbyname:");
	    printf (gettext (" temporary error"));
	    printf (gettext (" in name resolution\n"));
	    break;
	  }
	case HOST_NOT_FOUND:
	  {
	    printf ("gethostbyname:");
	    printf (gettext (" unknown host\n"));
	    break;
	  }
	default:
	  {
	    printf ("gethostbyname:");
	    printf (gettext (" non-recoverable"));
	    printf (gettext (" name server error\n"));
	  }
	}
      return -2;
    }
  memset (&proxy, 0, sizeof proxy);
  proxy.sin_family = AF_INET;
  memcpy (&proxy.sin_addr, proxy_hostent->h_addr, proxy_hostent->h_length);
  proxy.sin_port = htons (atoi (proxy_port));
  debug_printf (">connect\n");
  if (connect (proxy_socket[connection],
	       (struct sockaddr *) &proxy, sizeof proxy) < 0)
    {
      perror ("connect");
      return -3;
    }
  debug_printf ("connect>\n");
  status = PROXY_OK;
  strcpy (string, "CONNECT ");
  strcat (string, remote_host);
  strcat (string, ":");
  strcat (string, remote_port);
  strcat (string, " HTTP/1.1\r\nHost: ");
  strcat (string, remote_host);
  strcat (string, ":");
  strcat (string, remote_port);
  strcat (string, "\r\nUser-Agent: ");
  if (getenv ("USER_AGENT") != NULL)
    {
       strncpy (User_Agent, getenv ("USER_AGENT"), 255);
    }
  else
    {
       strcpy (User_Agent, "Mozilla/4.0 (compatible; MSIE 5.5; Windows 98)");
    }
  strcat (string, User_Agent);
  if (getenv ("PROXY_USER") != NULL)
    {
      char proxy_authorization_base64[257];

      strncpy (proxy_user, getenv ("PROXY_USER"), 255);
      base64_encode (proxy_user, proxy_authorization_base64);
      strcat (string, "\r\nProxy-authorization: Basic ");
      strcat (string, proxy_authorization_base64);
      debug_printf ("Proxy-authorization: Basic %s\n",
		    proxy_authorization_base64);
    }
  strcat (string, "\r\n\r\n");
  strsend (proxy_socket[connection], string);
  while (status == PROXY_OK)
    {
      if (wait_for_crlf (proxy_socket[connection]) < 0)
      {
	      EOC (connection);
	      return -4;
      }
      parse_HTTP_return_code ();
      if (!strcmp (HTTP_return_code, "200"))
	status = BICONNECTED;
      else
	status = PROXY_FAULT;
    }
  if (status == PROXY_FAULT)
    {
      /*
       * if PROXY_FAULT then write HTTP response to stdout
       */
      while ((count = read (proxy_socket[connection],
			    buffer, sizeof (buffer))) != 0)
	write (1, buffer, count);
      return -5;
    }
  /*
   * discard the rest of HTTP header until CR LF CR LF
   * (that is, to the beginning of the real connection)
   */
  if (wait_for_2crlf (proxy_socket[connection]) < 0)
    {
      return -6;
    }
  print_connection (connection,
		    gettext ("bidirectional connection stablished\n\n"));
  if (proxy_socket[connection] > maxfd)
    maxfd = proxy_socket[connection];
  FD_SET (proxy_socket[connection], &mask);
  debug_printf ("connect_host_to_proxy> (0)\n");
  return 0;
}

/*
 * Function : void initialize_gettext(void)
 * Purpose  : initializes gettext (i18n) extension
 * Params   : none
 */
void
initialize_gettext (void)
{
  debug_printf (">initialize_gettext()\n");
  setlocale (LC_ALL, "");
  bindtextdomain ("desproxy", LOCALEDIR);
  textdomain ("desproxy");
  debug_printf ("initilize_gettext>\n");
}

/*
 * Function : int bind_UDP_port(unsigned int request_port)
 * Purpose  : binds requested UDP port
 * Params   : unsigned int request_port - requested port
 */
int
bind_UDP_port (unsigned int request_port)
{
  int UDP_socket;

  debug_printf ("bind_UDP_port(%d)\n", request_port);
  if ((UDP_socket = socket (PF_INET, SOCK_DGRAM, 0)) < 0)
    {
      perror ("socket");
      exit (1);
    }
  memset (&server, 0, sizeof server);
  server.sin_family = AF_INET;
  server.sin_addr.s_addr = htonl (INADDR_ANY);
  server.sin_port = htons (request_port);
  if ((bind (UDP_socket, (struct sockaddr *) &server, sizeof server)) < 0)
    {
      perror ("bind");
      exit (1);
    }
  printf (gettext ("UDP port "));
  printf ("%d", request_port);
  printf (gettext (" Bound\n"));
  debug_printf ("bind_UDP_port> (%d)\n", UDP_socket);
  return (UDP_socket);
}

/*
 * Function : int listen_in_TCP_port(unsigned int request_port)
 * Purpose  : listens in requested TCP port for incoming connections
 * Parmas   : unsigned int request_port - requested port
 */
int
listen_in_TCP_port (unsigned int request_port)
{
  int request_socket;

  debug_printf ("listen_in_TCP_port(%d)\n", request_port);
  if ((request_socket = socket (PF_INET, SOCK_STREAM, 0)) < 0)
    {
      perror ("socket");
      exit (1);
    }
  memset (&server, 0, sizeof server);
  server.sin_family = AF_INET;
  server.sin_addr.s_addr = htonl (INADDR_ANY);
  server.sin_port = htons (request_port);
  if ((bind (request_socket, (struct sockaddr *) &server, sizeof server)) < 0)
    {
      perror ("bind");
      exit (1);
    }
  if (listen (request_socket, SOMAXCONN) < 0)
    {
      perror ("listen");
      exit (1);
    }
  printf (gettext ("TCP port "));
  printf ("%d", request_port);
  printf (gettext (" Bound & Listening\n"));
  debug_printf ("listen_in_TCP_port> (%d)\n", request_socket);
  return (request_socket);
}

/*
 * Function : int look_for_desproxy_conf(void)
 * NYI
 */
int
look_for_desproxy_conf (void)
{
  FILE *desproxy_conf;

  if ((desproxy_conf = fopen ("desproxy.conf", "r")) == NULL)
    {
      return 0;
    }
  fclose (desproxy_conf);
  return (1);
}

/*
 * Function : void turn_console_echo_off(void)
 * Purpose  : turns off console echo
 *          : stores old tty status in global variable old_tty
 * Params   : none
 */
void
turn_console_echo_off (void)
{
  struct termios tty;

  /*
   * Save the old tty settings
   */
  tcgetattr (0, &old_tty);

  /*
   * get rid of echo for the new tty settings.
   *
   * (from man tcgetattr)
   *
   * ICANON Enable canonical mode.  This  enables  the  special
   *        characters  EOF,  EOL,  EOL2,  ERASE,  KILL, LNEXT,
   *        REPRINT, STATUS, and WERASE, and buffers by  lines.
   *
   * ECHO   Echo input characters.
   * 
   * ECHOE  If ICANON is also set, the ERASE  character  erases
   *        the  preceding  input  character, and WERASE erases
   *        the preceding word.
   *
   * ECHOK  If ICANON is also set, the  KILL  character  erases
   *        the current line.
   *
   * ECHONL If  ICANON  is also set, echo the NL character even
   *        if ECHO is not set.
   */
  tty = old_tty;
  tty.c_lflag &= ~(ICANON | ECHO | ECHOE | ECHOK | ECHONL);

  /*
   * set new tty settings 
   *
   * (from man tcsetattr)
   *
   * TCSAFLUSH
   *
   *  the  change  occurs after all output written to the
   *  object referred by fd has been transmitted, and all
   *  input  that  has been received but not read will be
   *  discarded before the change is made.
   */
  tcsetattr (0, TCSAFLUSH, &tty);
}

/*
 * Function : void turn_console_echo_on(void)
 * Purpose  : turns on console echo
 *          : restores old tty status stored in global variable old_tty
 * Params   : none
 */
void
turn_console_echo_on (void)
{
  /*
   * Now reset the old settings
   */
  tcsetattr (0, TCSAFLUSH, &old_tty);
}

/*
 * Function : void get_username_and_password(void)
 * Purpose  : requests user to give username and password
 *          : strores them in global variables username & password
 * Params   : none
 */
void
get_username_and_password (void)
{
  strcpy (console_line, "");

  while (!strcmp (console_line, ""))
    {
      printf (gettext ("Username: "));
      strcpy (username, get_console_line ());
    }

  printf (gettext ("Password: "));

  /*
   * turn out echo, so password is not displayed when typed
   */
  turn_console_echo_off ();
  strcpy (password, get_console_line ());

  /*
   * turn on echo again
   */
  turn_console_echo_on ();

  /*
   * send \n because the one in the passwd didn't echo :)
   */
  printf ("\n");
}