/*
     This file is part of GNUnet.
     (C) 2007, 2008, 2009, 2010 Christian Grothoff (and other contributing authors)

     GNUnet is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 3, or (at your
     option) any later version.

     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
*/

/**
 * @file include/gnunet_nat_lib.h
 * @brief Library handling UPnP and NAT-PMP port forwarding and
 *     external IP address retrieval
 *
 * @author Milan Bouchet-Valat
 */

#ifndef GNUNET_NAT_LIB_H
#define GNUNET_NAT_LIB_H

#include "gnunet_util_lib.h"

/**
 * Signature of the callback passed to GNUNET_NAT_register.
 *
 * @param cls closure
 * @param add_remove GNUNET_YES to mean the new public IP address, GNUNET_NO to mean
 *     the previous (now invalid) one
 * @param addr either the previous or the new public IP address
 * @param addrlen actual lenght of the address
 */
typedef void (*GNUNET_NAT_AddressCallback) (void *cls, 
					    int add_remove,
                                            const struct sockaddr *addr,
                                            socklen_t addrlen);


/**
 * Handle for active NAT registrations.
 */
struct GNUNET_NAT_Handle;

/**
 * Attempt to enable port redirection and detect public IP address contacting
 * UPnP or NAT-PMP routers on the local network. Use addr to specify to which
 * of the local host's addresses should the external port be mapped. The port
 * is taken from the corresponding sockaddr_in[6] field.
 *
 * @param addr the local address packets should be redirected to
 * @param addrlen actual lenght of the address
 * @param callback function to call everytime the public IP address changes
 * @param callback_cls closure for callback
 * @return NULL on error, otherwise handle that can be used to unregister 
 */
struct GNUNET_NAT_Handle *
GNUNET_NAT_register (const struct sockaddr *addr,
		     socklen_t addrlen,
		     GNUNET_NAT_AddressCallback callback, 
		     void *callback_cls);


/**
 * Stop port redirection and public IP address detection for the given handle.
 * This frees the handle, after having sent the needed commands to close open ports.
 *
 * @param h the handle to stop
 */
void GNUNET_NAT_unregister (struct GNUNET_NAT_Handle *h);

#endif 

/* end of gnunet_nat_lib.h */