/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2007, 2008 University of Washington
 *
 * 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 POINT_TO_POINT_NET_DEVICE_H
#define POINT_TO_POINT_NET_DEVICE_H

#include <string.h>
#include "ns3/address.h"
#include "ns3/node.h"
#include "ns3/net-device.h"
#include "ns3/callback.h"
#include "ns3/packet.h"
#include "ns3/traced-callback.h"
#include "ns3/nstime.h"
#include "ns3/data-rate.h"
#include "ns3/ptr.h"
#include "ns3/mac48-address.h"

namespace ns3 {

class Queue;
class PointToPointChannel;
class ErrorModel;

/**
 * \class PointToPointNetDevice
 * \brief A Device for a Point to Point Network Link.
 *
 * This PointToPointNetDevice class specializes the NetDevice abstract
 * base class.  Together with a PointToPointChannel (and a peer 
 * PointToPointNetDevice), the class models, with some level of 
 * abstraction, a generic point-to-point or serial link.  
 * Key parameters or objects that can be specified for this device 
 * include a queue, data rate, and interframe transmission gap (the 
 * propagation delay is set in the PointToPointChannel).
 */
class PointToPointNetDevice : public NetDevice 
{
public:
  static TypeId GetTypeId (void);

  /**
   * Construct a PointToPointNetDevice
   *
   * This is the constructor for the PointToPointNetDevice.  It takes as a
   * parameter a pointer to the Node to which this device is connected, 
   * as well as an optional DataRate object.
   */
  PointToPointNetDevice ();

  /**
   * Destroy a PointToPointNetDevice
   *
   * This is the destructor for the PointToPointNetDevice.
   */
  virtual ~PointToPointNetDevice ();

  /**
   * Set the Data Rate used for transmission of packets.  The data rate is
   * set in the Attach () method from the corresponding field in the channel
   * to which the device is attached.  It can be overridden using this method.
   *
   * @see Attach ()
   * @param bps the data rate at which this object operates
   */
  void SetDataRate (DataRate bps);

  /**
   * Set the interframe gap used to separate packets.  The interframe gap
   * defines the minimum space required between packets sent by this device.
   *
   * @param t the interframe gap time
   */
  void SetInterframeGap (Time t);

  /**
   * Attach the device to a channel.
   *
   * @param ch Ptr to the channel to which this object is being attached.
   */
  bool Attach (Ptr<PointToPointChannel> ch);

  /**
   * Attach a queue to the PointToPointNetDevice.
   *
   * The PointToPointNetDevice "owns" a queue that implements a queueing 
   * method such as DropTail or RED.  
   *
   * @see Queue
   * @see DropTailQueue
   * @param queue Ptr to the new queue.
   */
  void SetQueue (Ptr<Queue> queue);

  /**
   * Get a copy of the attached Queue.
   *
   * @returns Ptr to the queue.
   */
  Ptr<Queue> GetQueue(void) const; 

  /**
   * Attach a receive ErrorModel to the PointToPointNetDevice.
   *
   * The PointToPointNetDevice may optionally include an ErrorModel in
   * the packet receive chain.
   *
   * @see ErrorModel
   * @param em Ptr to the ErrorModel.
   */
  void SetReceiveErrorModel(Ptr<ErrorModel> em);

  /**
   * Receive a packet from a connected PointToPointChannel.
   *
   * The PointToPointNetDevice receives packets from its connected channel
   * and forwards them up the protocol stack.  This is the public method
   * used by the channel to indicate that the last bit of a packet has 
   * arrived at the device.
   *
   * @see PointToPointChannel
   * @param p Ptr to the received packet.
   */
  void Receive (Ptr<Packet> p);

  // The remaining methods are documented in ns3::NetDevice*
  
  virtual void SetIfIndex(const uint32_t index);
  virtual uint32_t GetIfIndex(void) const;

  virtual Ptr<Channel> GetChannel (void) const;

  virtual void SetAddress (Address address);
  virtual Address GetAddress (void) const;

  virtual bool SetMtu (const uint16_t mtu);
  virtual uint16_t GetMtu (void) const;

  virtual bool IsLinkUp (void) const;

  virtual void AddLinkChangeCallback (Callback<void> callback);

  virtual bool IsBroadcast (void) const;
  virtual Address GetBroadcast (void) const;

  virtual bool IsMulticast (void) const;
  virtual Address GetMulticast (Ipv4Address multicastGroup) const;

  virtual bool IsPointToPoint (void) const;
  virtual bool IsBridge (void) const;

  virtual bool Send(Ptr<Packet> packet, const Address &dest, uint16_t protocolNumber);
  virtual bool SendFrom(Ptr<Packet> packet, const Address& source, const Address& dest, uint16_t protocolNumber);

  virtual Ptr<Node> GetNode (void) const;
  virtual void SetNode (Ptr<Node> node);

  virtual bool NeedsArp (void) const;

  virtual void SetReceiveCallback (NetDevice::ReceiveCallback cb);

  virtual Address GetMulticast (Ipv6Address addr) const;

  virtual void SetPromiscReceiveCallback (PromiscReceiveCallback cb);
  virtual bool SupportsSendFrom (void) const;

private:

  virtual void DoDispose (void);

private:

  /**
   * \returns the address of the remote device connected to this device
   * through the point to point channel.
   */
  Address GetRemote (void) const;

  /**
   * Adds the necessary headers and trailers to a packet of data in order to
   * respect the protocol implemented by the agent.
   * \param p packet
   * \param protocolNumber protocol number
   */
  void AddHeader(Ptr<Packet> p, uint16_t protocolNumber);

  /**
   * Removes, from a packet of data, all headers and trailers that
   * relate to the protocol implemented by the agent
   * \param p Packet whose headers need to be processed
   * \param param An integer parameter that can be set by the function
   * \return Returns true if the packet should be forwarded up the
   * protocol stack.
   */
  bool ProcessHeader(Ptr<Packet> p, uint16_t& param);

  /**
   * Start Sending a Packet Down the Wire.
   *
   * The TransmitStart method is the method that is used internally in the
   * PointToPointNetDevice to begin the process of sending a packet out on
   * the channel.  The corresponding method is called on the channel to let
   * it know that the physical device this class represents has virtually
   * started sending signals.  An event is scheduled for the time at which
   * the bits have been completely transmitted.
   *
   * @see PointToPointChannel::TransmitStart ()
   * @see TransmitCompleteEvent ()
   * @param p a reference to the packet to send
   * @returns true if success, false on failure
   */
  bool TransmitStart (Ptr<Packet> p);

  /**
   * Stop Sending a Packet Down the Wire and Begin the Interframe Gap.
   *
   * The TransmitComplete method is used internally to finish the process
   * of sending a packet out on the channel.
   */
  void TransmitComplete(void);

  void NotifyLinkUp (void);

  /**
   * Enumeration of the states of the transmit machine of the net device.
   */
  enum TxMachineState
    {
      READY, /**< The transmitter is ready to begin transmission of a packet */
      BUSY   /**< The transmitter is busy transmitting a packet */
    };
  /**
   * The state of the Net Device transmit state machine.
   * @see TxMachineState
   */
  TxMachineState m_txMachineState;

  /**
   * The data rate that the Net Device uses to simulate packet transmission
   * timing.
   * @see class DataRate
   */
  DataRate       m_bps;

  /**
   * The interframe gap that the Net Device uses to throttle packet
   * transmission
   * @see class Time
   */
  Time           m_tInterframeGap;

  /**
   * The PointToPointChannel to which this PointToPointNetDevice has been
   * attached.
   * @see class PointToPointChannel
   */
  Ptr<PointToPointChannel> m_channel;

  /**
   * The Queue which this PointToPointNetDevice uses as a packet source.
   * Management of this Queue has been delegated to the PointToPointNetDevice
   * and it has the responsibility for deletion.
   * @see class Queue
   * @see class DropTailQueue
   */
  Ptr<Queue> m_queue;

  /**
   * Error model for receive packet events
   */
  Ptr<ErrorModel> m_receiveErrorModel;

  /**
   * The trace source fired when packets come into the "top" of the device
   * at the L3/L2 transition, before being queued for transmission.
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_macTxTrace;

  /**
   * The trace source fired when packets coming into the "top" of the device
   * at the L3/L2 transition are dropped before being queued for transmission.
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_macTxDropTrace;

  /**
   * The trace source fired for packets successfully received by the device
   * immediately before being forwarded up to higher layers (at the L2/L3 
   * transition).  This is a promiscuous trace (which doesn't mean a lot here
   * in the point-to-point device).
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_macPromiscRxTrace;

  /**
   * The trace source fired for packets successfully received by the device
   * immediately before being forwarded up to higher layers (at the L2/L3 
   * transition).  This is a non-promiscuous trace (which doesn't mean a lot 
   * here in the point-to-point device).
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_macRxTrace;

  /**
   * The trace source fired for packets successfully received by the device
   * but are dropped before being forwarded up to higher layers (at the L2/L3 
   * transition).
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_macRxDropTrace;

  /**
   * The trace source fired when a packet begins the transmission process on
   * the medium.
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_phyTxBeginTrace;

  /**
   * The trace source fired when a packet ends the transmission process on
   * the medium.  
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_phyTxEndTrace;

  /**
   * The trace source fired when the phy layer drops a packet before it tries
   * to transmit it.
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_phyTxDropTrace;

  /**
   * The trace source fired when a packet begins the reception process from
   * the medium -- when the simulated first bit(s) arrive.
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_phyRxBeginTrace;

  /**
   * The trace source fired when a packet ends the reception process from
   * the medium.
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_phyRxEndTrace;

  /**
   * The trace source fired when the phy layer drops a packet it has received.
   * This happens if the receiver is not enabled or the error model is active
   * and indicates that the packet is corrupt.
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_phyRxDropTrace;

  /**
   * A trace source that emulates a non-promiscuous protocol sniffer connected 
   * to the device.  Unlike your average everyday sniffer, this trace source 
   * will not fire on PACKET_OTHERHOST events.
   *
   * On the transmit size, this trace hook will fire after a packet is dequeued
   * from the device queue for transmission.  In Linux, for example, this would
   * correspond to the point just before a device hard_start_xmit where 
   * dev_queue_xmit_nit is called to dispatch the packet to the PF_PACKET 
   * ETH_P_ALL handlers.
   *
   * On the receive side, this trace hook will fire when a packet is received,
   * just before the receive callback is executed.  In Linux, for example, 
   * this would correspond to the point at which the packet is dispatched to 
   * packet sniffers in netif_receive_skb.
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_snifferTrace;

  /**
   * A trace source that emulates a promiscuous mode protocol sniffer connected
   * to the device.  This trace source fire on packets destined for any host
   * just like your average everyday packet sniffer.
   *
   * On the transmit size, this trace hook will fire after a packet is dequeued
   * from the device queue for transmission.  In Linux, for example, this would
   * correspond to the point just before a device hard_start_xmit where 
   * dev_queue_xmit_nit is called to dispatch the packet to the PF_PACKET 
   * ETH_P_ALL handlers.
   *
   * On the receive side, this trace hook will fire when a packet is received,
   * just before the receive callback is executed.  In Linux, for example, 
   * this would correspond to the point at which the packet is dispatched to 
   * packet sniffers in netif_receive_skb.
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_promiscSnifferTrace;

  Ptr<Node> m_node;
  Mac48Address m_address;
  NetDevice::ReceiveCallback m_rxCallback;
  NetDevice::PromiscReceiveCallback m_promiscCallback;
  uint32_t m_ifIndex;
  bool m_linkUp;
  TracedCallback<> m_linkChangeCallbacks;

  static const uint16_t DEFAULT_MTU = 1500;

  /**
   * The Maximum Transmission Unit.  This corresponds to the maximum 
   * number of bytes that can be transmitted as seen from higher layers.
   * This corresponds to the 1500 byte MTU size often seen on IP over 
   * Ethernet.
   */
  uint32_t m_mtu;

  Ptr<Packet> m_currentPkt;

  /**
   * \brief PPP to Ethernet protocol number mapping
   * \param protocol A PPP protocol number
   * \return The corresponding Ethernet protocol number
   */
  static uint16_t PppToEther(uint16_t protocol);

  /**
   * \brief Ethernet to PPP protocol number mapping
   * \param protocol An Ethernet protocol number
   * \return The corresponding PPP protocol number
   */
  static uint16_t EtherToPpp(uint16_t protocol);
};

} // namespace ns3

#endif // POINT_TO_POINT_NET_DEVICE_H