/*
     This file is part of GNUnet
     (C) 2010, 2011 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 transport/plugin_transport_udp.h
 * @brief Implementation of the UDP transport protocol
 * @author Christian Grothoff
 * @author Nathan Evans
 * @author Matthias Wachs
 */
#include "platform.h"
#include "gnunet_hello_lib.h"
#include "gnunet_util_lib.h"
#include "gnunet_fragmentation_lib.h"
#include "gnunet_nat_lib.h"
#include "gnunet_protocols.h"
#include "gnunet_resolver_service.h"
#include "gnunet_signatures.h"
#include "gnunet_constants.h"
#include "gnunet_statistics_service.h"
#include "gnunet_transport_service.h"
#include "gnunet_transport_plugin.h"
#include "transport.h"

#define LOG(kind,...) GNUNET_log_from (kind, "transport-udp", __VA_ARGS__)

#define DEBUG_UDP GNUNET_NO
#define DEBUG_UDP_BROADCASTING GNUNET_NO

/**
 * MTU for fragmentation subsystem.  Should be conservative since
 * all communicating peers MUST work with this MTU.
 */
#define UDP_MTU 1400


GNUNET_NETWORK_STRUCT_BEGIN
/**
 * Network format for IPv4 addresses.
 */
struct IPv4UdpAddress
{
	/**
	 * Optional options and flags for this address
	 */
	uint32_t options GNUNET_PACKED;

  /**
   * IPv4 address, in network byte order.
   */
  uint32_t ipv4_addr GNUNET_PACKED;

  /**
   * Port number, in network byte order.
   */
  uint16_t u4_port GNUNET_PACKED;
};


/**
 * Network format for IPv6 addresses.
 */
struct IPv6UdpAddress
{
	/**
	 * Optional options and flags for this address
	 */
	uint32_t options GNUNET_PACKED;

  /**
   * IPv6 address.
   */
  struct in6_addr ipv6_addr GNUNET_PACKED;

  /**
   * Port number, in network byte order.
   */
  uint16_t u6_port GNUNET_PACKED;
};
GNUNET_NETWORK_STRUCT_END


/**
 * UDP Message-Packet header (after defragmentation).
 */
struct UDPMessage
{
  /**
   * Message header.
   */
  struct GNUNET_MessageHeader header;

  /**
   * Always zero for now.
   */
  uint32_t reserved;

  /**
   * What is the identity of the sender
   */
  struct GNUNET_PeerIdentity sender;

};


/**
 * Encapsulation of all of the state of the plugin.
 */
struct Plugin
{

  /**
   * Our environment.
   */
  struct GNUNET_TRANSPORT_PluginEnvironment *env;

  /**
   * Session of peers with whom we are currently connected,
   * map of peer identity to 'struct PeerSession'.
   */
  struct GNUNET_CONTAINER_MultiPeerMap *sessions;

  /**
   * Heap with all of our defragmentation activities.
   */
  struct GNUNET_CONTAINER_Heap *defrag_ctxs;

  /**
   * ID of select task
   */
  GNUNET_SCHEDULER_TaskIdentifier select_task;
  GNUNET_SCHEDULER_TaskIdentifier select_task_v6;

  /**
   * Tokenizer for inbound messages.
   */
  struct GNUNET_SERVER_MessageStreamTokenizer *mst;

  /**
   * Bandwidth tracker to limit global UDP traffic.
   */
  struct GNUNET_BANDWIDTH_Tracker tracker;

  /**
   * Address we were told to bind to exclusively (IPv4).
   */
  char *bind4_address;

  /**
   * Address we were told to bind to exclusively (IPv6).
   */
  char *bind6_address;


  /**
   * Bytes currently in buffer
   */
  int64_t bytes_in_buffer;

  /**
   * Handle to NAT traversal support.
   */
  struct GNUNET_NAT_Handle *nat;

  /**
   * FD Read set
   */
  struct GNUNET_NETWORK_FDSet *rs_v4;

  /**
   * FD Write set
   */
  struct GNUNET_NETWORK_FDSet *ws_v4;


  /**
   * The read socket for IPv4
   */
  struct GNUNET_NETWORK_Handle *sockv4;


  /**
   * FD Read set
   */
  struct GNUNET_NETWORK_FDSet *rs_v6;

  /**
   * FD Write set
   */
  struct GNUNET_NETWORK_FDSet *ws_v6;

  /**
   * The read socket for IPv6
   */
  struct GNUNET_NETWORK_Handle *sockv6;

  /**
   * Beacon broadcasting
   * -------------------
   */

  /**
   * Broadcast interval
   */
  struct GNUNET_TIME_Relative broadcast_interval;

  /**
   * Broadcast with IPv4
   */
  int broadcast_ipv4;

  /**
   * Broadcast with IPv6
   */
  int broadcast_ipv6;


  /**
   * Tokenizer for inbound messages.
   */
  struct GNUNET_SERVER_MessageStreamTokenizer *broadcast_ipv6_mst;
  struct GNUNET_SERVER_MessageStreamTokenizer *broadcast_ipv4_mst;

  /**
   * ID of select broadcast task
   */
  GNUNET_SCHEDULER_TaskIdentifier send_ipv4_broadcast_task;

  /**
   * ID of select broadcast task
   */
  GNUNET_SCHEDULER_TaskIdentifier send_ipv6_broadcast_task;

  /**
   * IPv6 multicast address
   */
  struct sockaddr_in6 ipv6_multicast_address;

  /**
   * DLL of IPv4 broadcast addresses
   */
  struct BroadcastAddress *ipv4_broadcast_tail;
  struct BroadcastAddress *ipv4_broadcast_head;

  /**
   * Is IPv6 enabled: GNUNET_YES or GNUNET_NO
   */
  int enable_ipv6;

  /**
   * Is IPv4 enabled: GNUNET_YES or GNUNET_NO
   */
  int enable_ipv4;

  /**
   * Port we broadcasting on.
   */
  uint16_t broadcast_port;

  /**
   * Port we listen on.
   */
  uint16_t port;

  /**
   * Port we advertise on.
   */
  uint16_t aport;

  struct UDP_MessageWrapper *ipv4_queue_head;
  struct UDP_MessageWrapper *ipv4_queue_tail;

  struct UDP_MessageWrapper *ipv6_queue_head;
  struct UDP_MessageWrapper *ipv6_queue_tail;
};


const char *
udp_address_to_string (void *cls, const void *addr, size_t addrlen);

void
udp_broadcast_receive ();

void
setup_broadcast (struct Plugin *plugin, struct sockaddr_in6 *server_addrv6, struct sockaddr_in *server_addrv4);

void
stop_broadcast (struct Plugin *plugin);

/* end of plugin_transport_udp.h */