/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2012 INRIA, 2012 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
 *
 * Author: Alina Quereilhac <alina.quereilhac@inria.fr>
 *         Claudio Freire <klaussfreire@sourceforge.net>
 */

#ifndef FD_NET_DEVICE_H
#define FD_NET_DEVICE_H

#include "ns3/address.h"
#include "ns3/callback.h"
#include "ns3/data-rate.h"
#include "ns3/event-id.h"
#include "ns3/mac48-address.h"
#include "ns3/net-device.h"
#include "ns3/node.h"
#include "ns3/packet.h"
#include "ns3/ptr.h"
#include "ns3/system-condition.h"
#include "ns3/traced-callback.h"
#include "ns3/unix-fd-reader.h"
#include "ns3/system-mutex.h"

#include <utility>
#include <queue>

namespace ns3 {


/**
 * \defgroup fd-net-device File Descriptor Network Device
 * This section documents the API of the ns-3 fd-net-device module.
 * For a generic functional description, please refer to the ns-3 manual.
 */

/**
 * \ingroup fd-net-device
 * \brief This class performs the actual data reading from the sockets.
 */
class FdNetDeviceFdReader : public FdReader
{
public:
  FdNetDeviceFdReader ();

  /**
   * Set size of the read buffer.
   */
  void SetBufferSize (uint32_t bufferSize);

private:
  FdReader::Data DoRead (void);

  uint32_t m_bufferSize; //!< size of the read buffer
};

class Node;

/**
 * \ingroup fd-net-device
 *
 * \brief a NetDevice to read/write network traffic from/into a file descriptor.
 *
 * A FdNetDevice object will read and write frames/packets from/to a file descriptor.
 * This file descriptor might be associated to a Linux TAP/TUN device, to a socket
 * or to a user space process, allowing the simulation to exchange traffic with the
 * "outside-world"
 *
 */
class FdNetDevice : public NetDevice
{
public:
  /**
   * \brief Get the type ID.
   * \return the object TypeId
   */
  static TypeId GetTypeId (void);

  /**
   * Enumeration of the types of frames supported in the class.
   */
  enum EncapsulationMode
  {
    DIX,         /**< DIX II / Ethernet II packet */
    LLC,         /**< 802.2 LLC/SNAP Packet*/
    DIXPI,       /**< When using TAP devices, if flag
                      IFF_NO_PI is not set on the device,
                      IP packets will have an extra header:
                      Flags [2 bytes]
                      Proto [2 bytes]
                      Raw protocol(IP, IPv6, etc) frame. */
  };

  /**
   * Constructor for the FdNetDevice.
   */
  FdNetDevice ();

  /**
   * Destructor for the FdNetDevice.
   */
  virtual ~FdNetDevice ();

  /**
   * Set the link layer encapsulation mode of this device.
   *
   * \param mode The link layer encapsulation mode of this device.
   *
   */
  void SetEncapsulationMode (FdNetDevice::EncapsulationMode mode);

  /**
   * Get the link layer encapsulation mode of this device.
   *
   * \returns The link layer encapsulation mode of this device.
   */
  FdNetDevice::EncapsulationMode GetEncapsulationMode (void) const;

  /**
   * Set the associated file descriptor.
   *
   */
  void SetFileDescriptor (int fd);

  /**
   * Set a start time for the device.
   *
   * @param tStart the start time
   */
  void Start (Time tStart);

  /**
   * Set a stop time for the device.
   *
   * @param tStop the stop time
   */
  void Stop (Time tStop);

  // inherited from NetDevice base class.
  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 void SetPromiscReceiveCallback (NetDevice::PromiscReceiveCallback cb);
  virtual bool SupportsSendFrom () const;
  virtual Address GetMulticast (Ipv6Address addr) const;

  /**
   * Set if the NetDevice is able to send Broadcast messages
   * \param broadcast true if the NetDevice can send Broadcast
   */
  virtual void SetIsBroadcast (bool broadcast);
  /**
   * Set if the NetDevice is able to send Multicast messages
   * \param multicast true if the NetDevice can send Multicast
   */
  virtual void SetIsMulticast (bool multicast);

protected:
  virtual void DoDispose (void);

private:
  /**
   * \brief Copy constructor
   *
   * Defined and unimplemented to avoid misuse as suggested in
   * http://www.nsnam.org/wiki/NS-3_Python_Bindings#.22invalid_use_of_incomplete_type.22
   */
  FdNetDevice (FdNetDevice const &);

  /**
   * Spin up the device
   */
  void StartDevice (void);

  /**
   * Tear down the device
   */
  void StopDevice (void);

  /**
   * Callback to invoke when a new frame is received
   */
  void ReceiveCallback (uint8_t *buf, ssize_t len);

  /**
   * Forward the frame to the appropriate callback for processing
   */
  void ForwardUp (void);

  /**
   * Start Sending a Packet Down the Wire.
   * @param p packet to send
   * @returns true if success, false on failure
   */
  bool TransmitStart (Ptr<Packet> p);

  /**
   * Notify that the link is up and ready
   */
  void NotifyLinkUp (void);

  /**
   * The ns-3 node associated to the net device.
   */
  Ptr<Node> m_node;

  /**
   * a copy of the node id so the read thread doesn't have to GetNode() in
   * in order to find the node ID.  Thread unsafe reference counting in
   * multithreaded apps is not a good thing.
   */
  uint32_t m_nodeId;

  /**
   * The ns-3 interface index (in the sense of net device index) that has been assigned to this network device.
   */
  uint32_t m_ifIndex;

  /**
   * The MTU associated to the file descriptor technology
   */
  uint16_t m_mtu;

  /**
   * The file descriptor used for receive/send network traffic.
   */
  int m_fd;

  /**
   * Reader for the file descriptor.
   */
  Ptr<FdNetDeviceFdReader> m_fdReader;

  /**
   * The net device mac address.
   */
  Mac48Address m_address;

  /**
   * The typ of encapsulation of the received/transmited frames.
   */
  EncapsulationMode m_encapMode;

  /**
   * Flag indicating whether or not the link is up.  In this case,
   * whether or not the device is connected to a channel.
   */
  bool m_linkUp;

  /**
   * Callbacks to fire if the link changes state (up or down).
   */
  TracedCallback<> m_linkChangeCallbacks;

  /**
   * Flag indicating whether or not the underlying net device supports
   * broadcast.
   */
  bool m_isBroadcast;

  /**
   * Flag indicating whether or not the underlying net device supports
   * multicast.
   */
  bool m_isMulticast;

  /**
   * Number of packets that were received and scheduled for read but not yeat read.
   */
  std::queue< std::pair<uint8_t *, ssize_t> > m_pendingQueue;

  /**
   * Maximum number of packets that can be received and scheduled for read but not yeat read.
   */
  uint32_t m_maxPendingReads;

  /**
   * Mutex to increase pending read counter.
   */
  SystemMutex m_pendingReadMutex;

  /**
   * Time to start spinning up the device
   */
  Time m_tStart;

  /**
   * Time to start tearing down the device
   */
  Time m_tStop;

  /**
   * NetDevice start event
   */
  EventId m_startEvent;
  /**
   * NetDevice stop event
   */
  EventId m_stopEvent;

  /**
   * The callback used to notify higher layers that a packet has been received.
   */
  NetDevice::ReceiveCallback m_rxCallback;

  /**
   * The callback used to notify higher layers that a packet has been received in promiscuous mode.
   */
  NetDevice::PromiscReceiveCallback m_promiscRxCallback;

  /**
   * 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.
   *
   * \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.
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_macRxTrace;

  /**
   * The trace source fired for packets successfully received by the device
   * but which 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 the phy layer drops a packet as it tries
   * to transmit it.
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_phyTxDropTrace;

  /**
   * The trace source fired when the phy layer drops a packet it has received.
   *
   * \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;

};

} // namespace ns3

#endif /* FD_NET_DEVICE_H */