/*
     This file is part of GNUnet.
     (C) 2012 Christian Grothoff

     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 exit/exit.h
 * @brief format for mesh messages exchanged between VPN service and exit daemon
 * @author Christian Grothoff
 */
#ifndef EXIT_H
#define EXIT_H

#include "gnunet_util_lib.h"

/**
 * Message send via mesh to an exit daemon to initiate forwarding of
 * TCP data to a local service.
 */
struct GNUNET_EXIT_TcpServiceStartMessage
{
  /**
   * Type is GNUNET_MESSAGE_TYPE_VPN_TCP_TO_SERVICE_START
   */
  struct GNUNET_MessageHeader header;

  /**
   * Always 0.
   */
  uint32_t reserved;

  /**
   * Identification for the desired service.
   */
  GNUNET_HashCode service_descriptor;

  /**
   * Skeleton of the TCP header to send.  Port numbers are to
   * be replaced and the checksum may be updated as necessary.
   */
  struct tcp_packet tcp_header;

  /* followed by TCP payload */
};


/**
 * Message send via mesh to an exit daemon to initiate forwarding of
 * TCP data to the Internet.
 */
struct GNUNET_EXIT_TcpInternetStartMessage
{
  /**
   * Type is GNUNET_MESSAGE_TYPE_VPN_TCP_TO_INTERNET_START
   */
  struct GNUNET_MessageHeader header;

  /**
   * Address family, AF_INET or AF_INET6, in network byte order.
   */
  int32_t af;

  /**
   * Skeleton of the TCP header to send.  Port numbers are to
   * be replaced and the checksum may be updated as necessary.
   */
  struct tcp_packet tcp_header;

  /* followed by IP address of the destination; either
     'struct in_addr' or 'struct in6_addr', depending on af */

  /* followed by TCP payload */
};


/**
 * Message send via mesh between VPN and entry and an exit daemon to 
 * transmit TCP data between the VPN entry and an exit session.  This
 * format is used for both Internet-exits and service-exits and
 * in both directions (VPN to exit and exit to VPN).
 */
struct GNUNET_EXIT_TcpDataMessage
{
  /**
   * Type is GNUNET_MESSAGE_TYPE_VPN_TCP_DATA
   */
  struct GNUNET_MessageHeader header;

  /**
   * Always 0.
   */
  uint32_t reserved;

  /**
   * Skeleton of the TCP header to send.  Port numbers are to
   * be replaced and the checksum may be updated as necessary.  (The destination port number should not be changed, as it contains the desired destination port.)
   */
  struct tcp_packet tcp_header;

  /* followed by TCP payload */
};


/**
 * Message send via mesh to an exit daemon to send
 * UDP data to a local service.
 */
struct GNUNET_EXIT_UdpServiceMessage
{
  /**
   * Type is GNUNET_MESSAGE_TYPE_VPN_UDP_TO_SERVICE
   */
  struct GNUNET_MessageHeader header;

  /**
   * Source port to use for the UDP request (0 to use a random port).  In NBO.
   */
  uint16_t source_port;

  /**
   * Destination port to use for the UDP request.  In NBO.
   */   
  uint16_t destination_port;

  /**
   * Identification for the desired service.
   */
  GNUNET_HashCode service_descriptor;

  /* followed by UDP payload */
};


/**
 * Message send via mesh to an exit daemon to forward
 * UDP data to the Internet.
 */
struct GNUNET_EXIT_UdpInternetMessage
{
  /**
   * Type is GNUNET_MESSAGE_TYPE_VPN_UDP_TO_INTERNET
   */
  struct GNUNET_MessageHeader header;

  /**
   * Address family, AF_INET or AF_INET6, in network byte order.
   */
  int32_t af;

  /**
   * Source port to use for the UDP request (0 to use a random port).  In NBO.
   */
  uint16_t source_port;

  /**
   * Destination port to use for the UDP request.  In NBO.
   */   
  uint16_t destination_port;

  /* followed by IP address of the destination; either
     'struct in_addr' or 'struct in6_addr', depending on af */

  /* followed by UDP payload */
};


/**
 * Message send from exit daemon back to the UDP entry point
 * (used for both Internet and Service exit replies).
 */
struct GNUNET_EXIT_UdpReplyMessage
{
  /**
   * Type is GNUNET_MESSAGE_TYPE_VPN_UDP_REPLY
   */
  struct GNUNET_MessageHeader header;

  /**
   * Source port to use for the UDP reply (0 to use the same
   * port as for the original request).  In NBO.
   */
  uint16_t source_port;

  /**
   * Destination port to use for the UDP reply (0 to use the same
   * port as for the original request).  In NBO.
   */   
  uint16_t destination_port;

  /* followed by UDP payload */
};


#endif