model/ndn-interest.h

/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
/*
 * Copyright (c) 2011 University of California, Los Angeles
 *
 * 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
 *
 * Author: Ilya Moiseenko <iliamo@cs.ucla.edu>
 *         Alexander Afanasyev <alexander.afanasyev@ucla.edu>
 */

#ifndef _NDN_INTEREST_HEADER_H_
#define _NDN_INTEREST_HEADER_H_

#include "ns3/simple-ref-count.h"
#include "ns3/nstime.h"
#include "ns3/packet.h"
#include "ns3/ptr.h"

#include <ns3/ndn-name.h>

namespace ns3 {

class Packet;

namespace ndn {

/**
 * @brief NDN Interest (wire formats are defined in wire)
 *
 **/
class Interest : public SimpleRefCount<Interest>
{
public:
  /**
   * \brief Constructor
   *
   * Creates a null header
   **/
  Interest (Ptr<Packet> payload = Create<Packet> ());

  /**
   * @brief Copy constructor
   */
  Interest (const Interest &interest);

  /**
   * \brief Set interest name
   *
   * @param name smart pointer to Name
   *
   **/
  void
  SetName (Ptr<Name> name);

  /**
   * \brief Another variant to set interest name
   *
   * @param name const reference to Name object
   *
   **/
  void
  SetName (const Name &name);
  
  /**
   * \brief Get interest name
   *
   * Gets name of the interest.
   **/
  const Name&
  GetName () const;

  /**
   * @brief Get smart pointer to the interest name (to avoid extra memory usage)
   */
  Ptr<const Name>
  GetNamePtr () const;

  /**
   * \brief Set Scope
   * Scope limits where the Interest may propagate. 
   * Scope 0 prevents propagation beyond the local ccnd (even to other applications on the same host).
   * Scope 1 limits propagation to the applications on the originating host. 
   * Scope 2 limits propagation to no further than the next host. 
   * Other values are not defined, and will cause the Interest message to be dropped.
   * Note that this is not a hop count - the value is not decremented as the interest is forwarded.
   * @param[in] scope interest scope
   */
  void
  SetScope (int8_t scope);

  /**
   * \brief Get Scope value
   * Scope limits where the Interest may propagate. 
   * Scope 0 prevents propagation beyond the local ccnd (even to other applications on the same host).
   * Scope 1 limits propagation to the applications on the originating host. 
   * Scope 2 limits propagation to no further than the next host. 
   * Other values are not defined, and will cause the Interest message to be dropped.
   * Note that this is not a hop count - the value is not decremented as the interest is forwarded.
   */
  int8_t
  GetScope () const;

  /**
   * \brief Set InterestLifetime
   * InterestLifetime indicates the (approximate) time remaining before the interest times out.
   * The timeout is relative to the arrival time of the interest at the current node.
   * \see http://www.ndn.org/releases/latest/doc/technical/InterestMessage.html for more information.
   * @param[in] time interest lifetime  
   */ 
  void
  SetInterestLifetime (Time time);

  /**
   * \brief Get InterestLifetime value
   * InterestLifetime indicates the (approximate) time remaining before the interest times out.
   * The timeout is relative to the arrival time of the interest at the current node.
   * \see http://www.ndn.org/releases/latest/doc/technical/InterestMessage.html for more information.
   */ 
  Time
  GetInterestLifetime () const;

  /**
   * \brief Set Nonce
   * Nonce carries a randomly-genenerated bytestring that is used to detect and discard duplicate Interest messages.
   * @param[in] nonce Unique packet identification number
   */
  void
  SetNonce (uint32_t nonce);

  /**
   * \brief Get Nonce value
   * Nonce carries a randomly-genenerated bytestring that is used to detect and discard duplicate Interest messages.
   *
   */
  uint32_t
  GetNonce () const;
  
  /**
   * @brief NACK Type
   * Specifies the type of Interest packet
   */
  enum
    {
      NORMAL_INTEREST = 0,
      NACK_LOOP = 10,
      NACK_CONGESTION = 11,
      NACK_GIVEUP_PIT = 12,
    };

  /**
   * \brief Mark the Interest as a Negative Acknowledgement
   * Three types of NACKs are supported
   * 1. NACK_LOOP 
   * 2. NACK_CONGESTION
   * 3. NACK_GIVEUP_PIT
   * @param[in] nackType  NACK_LOOP or NACK_CONGESTION or NACK_GIVEUP_PIT or NORMAL_INTEREST
   */
  void
  SetNack (uint8_t nackType); //using reserved field
    
  /**
  * \brief Get NACK type
  * Returns NACK_LOOP, NACK_CONGESTION or NACK_GIVEUP_PIT. 
  * Otherwise, in case of normal interest packet, returns NORMAL_INTEREST (equals 0).
  */
  uint8_t
  GetNack () const;

  /**
   * @brief Get virtual "payload" of interest packet
   *
   * This payload can carry packet tags
   */
  void
  SetPayload (Ptr<Packet> payload);

  /**
   * @brief Set virtual "payload" to interest packet
   *
   * This payload can carry packet tags
   */
  Ptr<const Packet>
  GetPayload () const;
  
  /**
   * @brief Get wire formatted packet
   *
   * If wire formatted packet has not been set before, 0 will be returned
   */
  inline Ptr<const Packet>
  GetWire () const;

  /**
   * @brief Set (cache) wire formatted packet
   */
  inline void
  SetWire (Ptr<const Packet> packet) const;

  /**
   * @brief Print Interest in plain-text to the specified output stream
   */
  void
  Print (std::ostream &os) const;
  
private:
  // NO_ASSIGN
  Interest &
  operator = (const Interest &other) { return *this; }
  
private:
  Ptr<Name> m_name;         ///< @brief Interest name
  uint8_t m_scope;          ///< @brief 0xFF not set, 0 local scope, 1 this host, 2 immediate neighborhood
  Time  m_interestLifetime; ///< @brief InterestLifetime
  uint32_t m_nonce;         ///< @brief Nonce. not used if zero
  uint8_t  m_nackType;      ///< @brief Negative Acknowledgement type
  Ptr<Packet> m_payload;    ///< @brief virtual payload

  mutable Ptr<const Packet> m_wire;
};

inline Ptr<const Packet>
Interest::GetWire () const
{
  return m_wire;
}

inline void
Interest::SetWire (Ptr<const Packet> packet) const
{
  m_wire = packet;
}

/**
 * @ingroup ndn-exceptions
 * @brief Class for Interest parsing exception 
 */
class InterestException {};

} // namespace ndn
} // namespace ns3

#endif // _NDN_INTEREST_HEADER_H_