/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 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 EMU_NET_DEVICE_H
#define EMU_NET_DEVICE_H

#include <cstring>

#include "ns3/address.h"
#include "ns3/net-device.h"
#include "ns3/node.h"
#include "ns3/callback.h"
#include "ns3/packet.h"
#include "ns3/traced-callback.h"
#include "ns3/event-id.h"
#include "ns3/nstime.h"
#include "ns3/data-rate.h"
#include "ns3/ptr.h"
#include "ns3/mac48-address.h"
#include "ns3/system-thread.h"
#include "ns3/system-mutex.h"

namespace ns3 {

class Queue;

/**
 * \defgroup emu Emu Network Device
 * This section documents the API of the ns-3 emu module. For a generic functional description, please refer to the ns-3 manual.
 */

/**
 * \ingroup emu
 * \class EmuNetDevice
 * \brief A Device for an Emu Network Link.
 */
class EmuNetDevice : public NetDevice 
{
public:
  static TypeId GetTypeId (void);

  /**
   * Enumeration of the types of packets supported in the class.
   */
  enum EncapsulationMode {
    ILLEGAL,     /**< Encapsulation mode not set */
    DIX,         /**< DIX II / Ethernet II packet */
    LLC,         /**< 802.2 LLC/SNAP Packet*/
  };

  /**
   * Construct a EmuNetDevice
   *
   * This is the constructor for the EmuNetDevice.  It takes as a
   */
  EmuNetDevice ();

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

  /**
   * Set the Data Rate used for transmission of packets.
   *
   * @see Attach ()
   * @param bps the data rate at which this object operates
   */
  void SetDataRate (DataRate bps);

  /**
   * 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);

  /**
   * Attach a queue to the EmuNetDevice.
   *
   * The EmuNetDevice "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;


//
// Pure virtual methods inherited from NetDevice we must implement.
//
  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;

  /**
   * \brief Make and return a MAC multicast address using the provided
   *        multicast group
   *
   * \RFC{1112} says that an Ipv4 host group address is mapped to an Ethernet 
   * multicast address by placing the low-order 23-bits of the IP address into 
   * the low-order 23 bits of the Ethernet multicast address 
   * 01-00-5E-00-00-00 (hex).
   *
   * This method performs the multicast address creation function appropriate
   * to an EUI-48-based CSMA device.  This MAC address is encapsulated in an
   *  abstract Address to avoid dependencies on the exact address format.
   *
   * \param multicastGroup The IP address for the multicast group destination
   * of the packet.
   * \return The MAC multicast Address used to send packets to the provided
   * multicast group.
   *
   * \see Ipv4Address
   * \see Mac48Address
   * \see Address
   */
  virtual Address GetMulticast (Ipv4Address multicastGroup) const;

  /**
   * \brief Get the MAC multicast address corresponding
   * to the IPv6 address provided.
   * \param addr IPv6 address
   * \return the MAC multicast address
   * \warning Calling this method is invalid if IsMulticast returns not true.
   */
  virtual Address GetMulticast (Ipv6Address addr) const;

  /**
   * Is this a point to point link?
   * \returns false.
   */
  virtual bool IsPointToPoint (void) const;

  /**
   * Is this a bridge?
   * \returns false.
   */
  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 (PromiscReceiveCallback cb);

  virtual bool SupportsSendFrom (void) const;

  /**
   * Set the encapsulation mode of this device.
   *
   * \param mode The encapsulation mode of this device.
   *
   * \see SetFrameSize
   */
  void SetEncapsulationMode (EmuNetDevice::EncapsulationMode mode);

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

private:
  EmuNetDevice (const EmuNetDevice &);
  EmuNetDevice & operator= (const EmuNetDevice &);

  virtual void DoDispose (void);

  /**
   * Call out to a separate process running as suid root in order to get a raw 
   * socket.  We do this to avoid having the entire simulation running as root.
   * If this method returns, we'll have a raw socket waiting for us in m_sock.
   */
  void CreateSocket (void);

  /**
   * Figure out where the raw socket creation process lives on the system.
   */
  std::string FindCreator (std::string creatorName);

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

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

  /**
   * Loop to read and process packets
   */
  void ReadThread (void);

  /**
   * Method to handle received packets.  Synchronized with simulator via ScheduleNow from ReadThread.
   */
  void ForwardUp (uint8_t *buf, uint32_t len);

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

  void NotifyLinkUp (void);

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

  /**
   * 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 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 as it tries
   * to transmit it.
   *
   * \see class CallBackTraceSource
   */
  TracedCallback<Ptr<const Packet> > m_phyTxDropTrace;

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

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

  /**
   * The trace source fired when a packet begins 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.
   *
   * \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;

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

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

  EventId m_startEvent;
  EventId m_stopEvent;

  int32_t m_sock;

  Ptr<SystemThread> m_readThread;

  /**
   * The Node to which this device is attached.
   */
  Ptr<Node> m_node;

  /**
   * The MAC address which has been assigned to this device.
   */
  Mac48Address m_address;

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

  /**
   * The Unix interface index that we got from the system and which corresponds to the interface (e.g., "eth1")
   * we are using to talk to the network.  Valid when m_sock is valid.
   */
  int32_t m_sll_ifindex;

  /**
   * The type of packet that should be created by the AddHeader
   * function and that should be processed by the ProcessHeader
   * function.
   */
  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;

  /**
   * 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;

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

  /**
   * The unix/linux name of the underlying device (e.g., eth0)
   */
  std::string m_deviceName;

  /**
   * A 64K buffer to hold packet data while it is being sent.
   */
  uint8_t *m_packetBuffer;

  /*
   * 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;

  uint32_t m_maxPendingReads;
  uint32_t m_pendingReadCount;
  SystemMutex m_pendingReadMutex;
};

} // namespace ns3

#endif /* EMU_NET_DEVICE_H */
