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

/*

 * Copyright (c) 2005,2006 INRIA

 * All rights reserved.

 *

 * 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: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

 */

#ifndef NET_DEVICE_H

#define NET_DEVICE_H

#include <string>

#include <stdint.h>

#include "ns3/callback.h"

#include "ns3/packet.h"

#include "mac-address.h"

namespace ns3 {

class Node;

class TraceResolver;

class TraceContext;

class Channel;

/**

 * \brief Network layer to device interface

 *

 * This interface defines the API which the IP and ARP

 * layers need to access to manage an instance of a network device 

 * layer. It currently does not support MAC-level 

 * multicast but this should not be too hard to add by adding

 * extra methods to register MAC multicast addresses to

 * filter out unwanted packets before handing them to the

 * higher layers.

 *

 * In Linux, this interface is analogous to the interface

 * just above dev_queue_xmit() (i.e., IP packet is fully

 * constructed with destination MAC address already selected).

 * 

 * If you want to write a new MAC layer, you need to subclass

 * this base class and implement your own version of the

 * NetDevice::SendTo method.

 */

class NetDevice {

 public:

  /**

   * \param node base class node pointer of device's node 

   * \param addr MAC address of this device.

   */

  NetDevice(Node* node, const MacAddress& addr);

  virtual ~NetDevice() {}

  /**

   * \param context the trace context to use to construct the

   *        TraceResolver to return

   * \returns a TraceResolver which can resolve all traces

   *          performed in this object. The caller must

   *          delete the returned object.

   */

  TraceResolver *CreateTraceResolver (TraceContext const &context);

  /**

   * \return the channel this NetDevice is connected to. The value

   *         returned can be zero if the NetDevice is not yet connected

   *         to any channel.

   */

  Channel *GetChannel (void) const;

  /**

   * \return the current MacAddress of this interface.

   */

  MacAddress GetAddress (void) const;

  /**

   * \param mtu MTU value, in bytes, to set for the device

   * \return whether the MTU value was within legal bounds

   * 

   * Override for default MTU defined on a per-type basis.

   */

  bool SetMtu (const uint16_t mtu);

  /**

   * \return the link-level MTU in bytes for this interface.

   * 

   * This value is typically used by the IP layer to perform

   * IP fragmentation when needed.

   */

  uint16_t GetMtu (void) const;

  /**

   * \param name name of the device (e.g. "eth0")

   */

  void SetName(const std::string name); 

  /**

   * \return name name of the device (e.g. "eth0")

   */

  std::string GetName(void) const;

  /**

   * \return true if link is up; false otherwise

   */

  bool IsLinkUp (void) const;

  /**

   * \param callback the callback to invoke

   *

   * Register a callback invoked whenever the link 

   * status changes to UP. This callback is typically used

   * by the IP/ARP layer to flush the ARP cache 

   * whenever the link goes up.

   */

  void SetLinkChangeCallback (Callback<void> callback);

  /**

   * \return true if this interface supports a broadcast address,

   *         false otherwise.

   */

  bool IsBroadcast (void) const;

  /**

   * \return the broadcast address supported by

   *         this netdevice.

   *

   * Calling this method is invalid if IsBroadcast returns

   * not true.

   */

  MacAddress const &GetBroadcast (void) const;

  /**

   * \return value of m_isMulticast flag

   */

  bool IsMulticast (void) const;

  /**

   * \return value of m_isPointToPoint flag

   */

  bool IsPointToPoint (void) const;

  /**

   * \param p packet sent from above down to Network Device

   * \param dest mac address of the destination (already resolved)

   * \param protocolNumber identifies the type of payload contained in

   *        this packet. Used to call the right L3Protocol when the packet

   *        is received.

   * 

   *  Called from higher layer to send packet into Network Device

   *  to the specified destination MacAddress

   * 

   * \return whether the Send operation succeeded 

   */

  bool Send(Packet& p, const MacAddress& dest, uint16_t protocolNumber);

  bool NeedsArp (void) const;

  void SetReceiveCallback (Callback<bool,NetDevice *,const Packet &,uint16_t> cb);

 protected:

  /**

   * Enable broadcast support. This method should be

   * called by subclasses from their constructor

   */

  void EnableBroadcast (MacAddress broadcast);

  /**

   * Set m_isBroadcast flag to false

   */

  void DisableBroadcast (void);

  /**

   * Set m_isMulticast flag to true

   */

  void EnableMulticast (void);

  /**

   * Set m_isMulticast flag to false

   */

  void DisableMulticast (void);

  /**

   * Set m_isPointToPoint flag to true

   */

  void EnablePointToPoint (void);

  /**

   * Set m_isPointToPoint flag to false

   */

  void DisablePointToPoint (void);

  /**

   * When a subclass notices that the link status has changed to up,

   * it notifies its parent class by calling this method. This method

   * is responsible for notifying any LinkUp callbacks. 

   */

  void NotifyLinkUp (void);

  /**

   * When a subclass notices that the link status has changed to 

   * down, it notifies its parent class by calling this method.

   */

  void NotifyLinkDown (void);

  /**

   * \returns the node base class which contains this network

   *          interface.

   *

   * When a subclass needs to get access to the underlying node

   * base class to print the nodeid for example, it can invoke

   * this method.

   */

  Node* GetNode (void) const;

  /**

   * \param p packet sent from below up to Network Device

   * \returns true if the packet was forwarded successfully,

   *          false otherwise.

   *

   * When a subclass gets a packet from the channel, it 

   * forwards it to the higher layers by calling this method

   * which is responsible for passing it up to the Rx callback.

   */

  bool ForwardUp (Packet& p);

 private:

  /**

   * \param p packet to send

   * \param dest address of destination to which packet must be sent

   * \returns true if the packet could be sent successfully, false

   *          otherwise.

   *

   * This is the private virtual target function of the public Send()

   * method.  When the link is Up, this method is invoked to ask 

   * subclasses to forward packets. Subclasses MUST override this method.

   */

  virtual bool SendTo (Packet& p, const MacAddress& dest) = 0;

  virtual bool DoNeedsArp (void) const = 0;

  virtual TraceResolver *DoCreateTraceResolver (TraceContext const &context) = 0;

  virtual Channel *DoGetChannel (void) const = 0;

  Node*         m_node;

  std::string   m_name;

  uint16_t      m_ifIndex;

  MacAddress    m_address;

  MacAddress    m_broadcast;

  uint16_t      m_mtu;

  bool          m_isUp;

  bool          m_isBroadcast;

  bool          m_isMulticast;

  bool          m_isPointToPoint;

  Callback<void> m_linkChangeCallback;

  Callback<bool,NetDevice *,const Packet &,uint16_t> m_receiveCallback;

};

}; // namespace ns3

#endif