/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2008 University of Washington

 * Copyright (c) 2011 Atishay Jain

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation;

 *

 * This program 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 this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#ifndef IPV6_ADDRESS_GENERATOR_H

#define IPV6_ADDRESS_GENERATOR_H

#include "ns3/ipv6-address.h"

namespace ns3 {

/**

 * \ingroup address

 *

 * \brief This generator assigns addresses sequentially from a provided

 * network address; used in topology code. It also keeps track of all

 * addresses assigned to perform duplicate detection.

 *

 * Global unicast IPv6 addresses based on RFC 4291 definition:

 *

 *     |         n bits          |   m bits  |       128-n-m bits         |

 *     +-------------------------+-----------+----------------------------+

 *     | global routing prefix   | subnet ID |       interface ID         |

 *     +-------------------------+-----------+----------------------------+

 *

 * In this class, the first two quantities (n + m) are what is called the

 * 'net', and the 'prefix' defines the length in bits of (n + m).

 *

 * The way this is expected to be used is that, after initializing the

 * network and interfaceId to a number, a user can call NextAddress ()

 * repeatedly to obtain new interface IDs with the current network (for

 * multiple addresses on the link) and can call NextNetwork () to increment

 * the subnet ID.

 *

 * The interface ID is often an EUI-64 address derived from the MAC address,

 * but can also be a pseudo-random value (RFC 3041).  This implementation

 * does not generate EUI-64-based interface IDs.

 */

class Ipv6AddressGenerator

{

public:

  /**

   * \brief Initialise the base network and interfaceId for the generator

   *

   * The first call to NextAddress() or GetAddress() will return the

   * value passed in.

   *

   * \param net The network for the base Ipv6Address

   * \param prefix The prefix of the base Ipv6Address

   * \param interfaceId The base interface ID used for initialization

   */

  static void Init (const Ipv6Address net, const Ipv6Prefix prefix,

                    const Ipv6Address interfaceId = "::1");

  /**

   * \brief Get the next network acoording to the given Ipv6Prefix

   *

   * This operation is a pre-increment, meaning that the internal state

   * is changed before returning the new network address.

   *

   * This also resets the interface ID to the base interface ID that was

   * used for initialization.

   *

   * \param prefix The Ipv6Prefix used to set the next network

   */

  static Ipv6Address NextNetwork (const Ipv6Prefix prefix);

  /**

   * \brief Get the current network of the given Ipv6Prefix

   *

   * Does not change the internal state; this just peeks at the current

   * network

   *

   * \param prefix The Ipv6Prefix for the current network

   */

  static Ipv6Address GetNetwork (const Ipv6Prefix prefix);

  /**

   * \brief Set the interfaceId for the given Ipv6Prefix

   *

   * \param interfaceId The interfaceId to set for the current Ipv6Prefix

   * \param prefix The Ipv6Prefix whose address is to be set

   */

  static void InitAddress (const Ipv6Address interfaceId, const Ipv6Prefix prefix);

  /**

   * \brief Allocate the next Ipv6Address for the configured network and prefix

   *

   * This operation is a post-increment, meaning that the first address

   * allocated will be the one that was initially configured.

   * .

   * \param prefix The Ipv6Prefix for the current network

   */

  static Ipv6Address NextAddress (const Ipv6Prefix prefix);

  /**

   * \brief Get the Ipv6Address that will be allocated upon NextAddress()

   *

   * Does not change the internal state; just is used to peek the next

   * address that will be allocated upon NextAddress ()

   *

   * \param prefix The Ipv6Prefix for the current network

   */

  static Ipv6Address GetAddress (const Ipv6Prefix prefix);

  /**

   * \brief Reset the networks and Ipv6Address to zero

   */

  static void Reset (void);

  /**

   * \brief Add the Ipv6Address to the list of IPv6 entries

   *

   * Typically, this is used by external address allocators that want

   * to make use of this class's ability to track duplicates.  AddAllocated

   * is always called internally for any address generated by NextAddress()

   *

   * \param addr The Ipv6Address to be added to the list of Ipv6 entries

   */

  static bool AddAllocated (const Ipv6Address addr);

  /**

   * \brief Used to turn off fatal errors and assertions, for testing

   */

  static void TestMode (void);

};

}; // namespace ns3

#endif /* IPV6_ADDRESS_GENERATOR_H */