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

/*

 * Copyright (c) 2007 Emmanuelle Laprise

 *

 * 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: Emmanuelle Laprise <emmanuelle.laprise@bluekazoo.ca

 */

#ifndef CSMA_NET_DEVICE_H

#define CSMA_NET_DEVICE_H

#include <string.h>

#include "ns3/node.h"

#include "ns3/backoff.h"

#include "ns3/address.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/random-variable.h"

#include "ns3/mac48-address.h"

namespace ns3 {

class Queue;

class CsmaChannel;

class ErrorModel;

/**

 * \class CsmaNetDevice

 * \brief A Device for a Csma Network Link.

 *

 * The Csma net device class is analogous to layer 1 and 2 of the

 * TCP stack. The NetDevice takes a raw packet of bytes and creates a

 * protocol specific packet from them. 

 *

 * The Csma net device class takes a packet and adds (or removes) the 

 * headers/trailers that are associated with EthernetV1, EthernetV2, RAW

 * or LLC protocols. The EthernetV1 packet type adds and removes Ethernet

 * destination and source addresses. The LLC packet type adds and

 * removes LLC snap headers. The raw packet type does not add or

 * remove any headers.  

 *

 * Each Csma net device will receive all packets written to the Csma link. 

 * The ProcessHeader function can be used to filter out the packets such that

 * higher level layers only receive packets that are addressed to their

 * associated net devices

 */

class CsmaNetDevice : public NetDevice 

{

public:

  static TypeId GetTypeId (void);

  /**

   * Enumeration of the types of packets supported in the class.

   *

   */

  enum EncapsulationMode {

    ETHERNET_V1, /**< Version one ethernet packet, length field */

    IP_ARP,      /**< Ethernet packet encapsulates IP/ARP packet */

    RAW,         /**< Packet that contains no headers */

    LLC,         /**< LLC packet encapsulation */  

  };

  /**

   * Construct a CsmaNetDevice

   *

   * This is the default constructor for a CsmaNetDevice.

   */

  CsmaNetDevice ();

  /**

   * Destroy a CsmaNetDevice

   *

   * This is the destructor for a CsmaNetDevice.

   */

  virtual ~CsmaNetDevice ();

  /**

   * Set the inteframe gap used to separate packets.  The interframe gap

   * defines the minimum space required between packets sent by this device.

   * As in Ethernet, it defaults to 96 bit times.

   *

   * \param t the interframe gap time

   */

  void SetInterframeGap (Time t);

  /**

   * Set the backoff parameters used to determine the wait to retry

   * transmitting a packet when the channel is busy.

   *

   * \see Attach ()

   * \param slotTime Length of a packet slot (or average packet time)

   * \param minSlots Minimum number of slots to wait

   * \param maxSlots Maximum number of slots to wait

   * \param maxRetries Maximum number of retries before packet is discard

   * \param ceiling Cap on the exponential function when calculating max slots

   */

  void SetBackoffParams (Time slotTime, uint32_t minSlots, uint32_t maxSlots, 

    uint32_t maxRetries, uint32_t ceiling);

  /**

   * Attach the device to a channel.

   *

   * The function Attach is used to add a CsmaNetDevice to a CsmaChannel.

   *

   * \see SetDataRate ()

   * \see SetInterframeGap ()

   * \param ch a pointer to the channel to which this object is being attached.

   */

  bool Attach (Ptr<CsmaChannel> ch);

  /**

   * Attach a queue to the CsmaNetDevice.

   *

   * The CsmaNetDevice "owns" a queue.  This queue may be set by higher

   * level topology objects to implement a particular queueing method such as

   * DropTail or RED.  

   *

   * \see Queue

   * \see DropTailQueue

   * \param queue a Ptr to the queue for being assigned to the device.

   */

  void SetQueue (Ptr<Queue> queue);

  /**

   * Attach a receive ErrorModel to the CsmaNetDevice.

   *

   * The CsmaNetDevice may optionally include an ErrorModel in

   * the packet receive chain to simulate data errors in during transmission.

   *

   * \see ErrorModel

   * \param em a pointer to the ErrorModel 

   */

  void SetReceiveErrorModel (Ptr<ErrorModel> em);

  /**

   * Receive a packet from a connected CsmaChannel.

   *

   * The CsmaNetDevice 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 CsmaChannel

   * \param p a reference to the received packet

   * \param sender the CsmaNetDevice that transmitted the packet in the first place

   */

  void Receive (Ptr<Packet> p, Ptr<CsmaNetDevice> sender);

  /**

   * Is the send side of the network device enabled?

   *

   * \returns True if the send side is enabled, otherwise false.

   */

  bool IsSendEnabled (void);

  /**

   * Enable or disable the send side of the network device.

   *

   * \param enable Enable the send side if true, otherwise disable.

   */

  void SetSendEnable (bool enable);

  /**

   * Is the receive side of the network device enabled?

   *

   * \returns True if the receiver side is enabled, otherwise false.

   */

  bool IsReceiveEnabled (void);

  /**

   * Enable or disable the receive side of the network device.

   *

   * \param enable Enable the receive side if true, otherwise disable.

   */

  void SetReceiveEnable (bool enable);

  /**

   * Set the MAC address of the the network device.

   *

   * \param addr The Mac48Address to use as the address of the device.

   */

  void SetAddress (Mac48Address addr);

  /**

   * Set The max PHY-level payload length of packets sent over this device.

   *

   * level protocols see.  We have a PHY-level MTU which is the maximum number of bytes we can send over the link 

   * (cf. 1500 bytes for Ethernet).  The value that determines the relationship between these two values is the link

   *

   *

   * Consider the following situation:  A user wants to set the physical layer MTU to 1400 bytes instead of 1500.  This

   * user shouldn't have to concern herself that the current encapuslation mode is LLC and this will consume eight bytes.

   * She should not have to also set the MAC MTU to 1392 bytes, and she should certainly not have to do this before setting

   *

   *

   * Now, consider a user who is only interested in changing the encapsulation mode from LLC/SNAP to ETHERNET_V1.  This 

   * is going to change the relationship between the MAC MTU and the PHY MTU.  We've may have to come up with a new value 

   *

   *

   * - If the user is changing the encapsulation mode, the PHY MTU will remain fixed and the MAC MTU will change, if required,

   * to make the three values consistent;

   *

   * - If the user is changing the MAC MTU, she is interested in getting that part of the system set, so the PHY MTU

   * will be changed to make the three values consistent;

   *

   * - If the user is changing the PHY MTU, he is interested in getting that part of the system set, so the MAC MTU

   * 

   * So, if a user calls SetMaxPayloadLength, we assume that the PHY-level MTU is the interesting thing for that user and

   * SetMacMtu, we assume that the MAC-level MTU is the interesting property for that user, and we adjust the PHY-level MTU 

   * MAC-level MTU as the free variable and set its value to match the current PHY-level MTU.

   *

   * \param mayPayloadLength The max PHY-level payload length of packets sent over this device.

   */

  void SetMaxPayloadLength (uint16_t maxPayloadLength);

  /**

   * Get The max PHY-level payload length of packets sent over this device.

   *

   * \returns The max PHY-level payload length of packets sent over this device.

   */

  uint16_t GetMaxPayloadLength (void) const;

  /**

   * Set The MAC-level MTU (client payload) of packets sent over this device.

   *

   * \param mtu The MAC-level MTU (client payload) of packets sent over this device.

   *

   * \see SetMaxPayloadLength

   */

  void SetMacMtu (uint16_t mtu);

  /**

   * Get The MAC-level MTU (client payload) of packets sent over this device.

   *

   * \returns The MAC-level MTU (client payload) of packets sent over this device.

   */

  uint16_t GetMacMtu (void) const;

  /**

   * Set the encapsulation mode of this device.

   *

   * \param mode The encapsulation mode of this device.

   *

   * \see SetMaxPayloadLength

   */

  void SetEncapsulationMode (CsmaNetDevice::EncapsulationMode mode);

  /**

   * Get the encapsulation mode of this device.

   *

   * \returns The encapsulation mode of this device.

   */

  CsmaNetDevice::EncapsulationMode  GetEncapsulationMode (void);

  //

  // The following methods are inherited from NetDevice base class.

  //

  virtual void SetName (const std::string name);

  virtual std::string GetName (void) const;

  virtual void SetIfIndex (const uint32_t index);

  virtual uint32_t GetIfIndex (void) const;

  virtual Ptr<Channel> GetChannel (void) const;

  virtual bool SetMtu (const uint16_t mtu);

  virtual uint16_t GetMtu (void) const;

  virtual Address GetAddress (void) const;

  virtual bool IsLinkUp (void) const;

  virtual void SetLinkChangeCallback (Callback<void> callback);

  virtual bool IsBroadcast (void) const;

  virtual Address GetBroadcast (void) const;

  virtual bool IsMulticast (void) const;

  virtual Address GetMulticast (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 MakeMulticastAddress (Ipv4Address multicastGroup) const;

  /**

   * Is this a point to point link?

   * \returns false.

   */

  virtual bool IsPointToPoint (void) const;

  /**

   * Start sending a packet down the channel.

   */

  virtual bool Send (Ptr<Packet> packet, const Address& dest, 

    uint16_t protocolNumber);

  /**

   * Start sending a packet down the channel, with MAC spoofing

   */

  virtual bool SendFrom (Ptr<Packet> packet, const Address& source, const Address& dest, 

                         uint16_t protocolNumber);

  /**

   * Get the node to which this device is attached.

   *

   * \returns Ptr to the Node to which the device is attached.

   */

  virtual Ptr<Node> GetNode (void) const;

  /**

   * Set the node to which this device is being attached.

   *

   * \param node Ptr to the Node to which the device is being attached.

   */

  virtual void SetNode (Ptr<Node> node);

  /**

   * Does this device need to use the address resolution protocol?

   *

   * \returns True if the encapsulation mode is set to a value that requires

   * ARP (IP_ARP or LLC).

   */

  virtual bool NeedsArp (void) const;

  /**

   * Set the callback to be used to notify higher layers when a packet has been

   * received.

   *

   * \param cb The callback.

   */

  virtual void SetReceiveCallback (NetDevice::ReceiveCallback cb);

  virtual void SetPromiscReceiveCallback (PromiscReceiveCallback cb);

  virtual bool SupportsPromiscuous (void) const;

protected:

  /**

   * Perform any object release functionality required to break reference 

   * cycles in reference counted objects held by the device.

   */

  virtual void DoDispose (void);

  /**

   * Get a copy of the attached Queue.

   *

   * This method is provided for any derived class that may need to get

   * direct access to the underlying queue.

   *

   * \return a pointer to the queue.

   */

  Ptr<Queue> GetQueue (void) const; 

  /**

   * Adds the necessary headers and trailers to a packet of data in order to

   * respect the packet type

   *

   * \param p Packet to which header should be added

   * \param dest MAC destination address to which packet should be sent

   * \param protocolNumber In some protocols, identifies the type of

   * payload contained in this packet.

   */

  void AddHeader (Ptr<Packet> p, Mac48Address source, Mac48Address dest, uint16_t protocolNumber);

  /**

   * Removes, from a packet of data, all headers and trailers that

   * relate to the packet type

   *

   * \param p Packet whose headers need to be processed

   * \param param An integer parameter that can be set by the function

   * to return information gathered in the header

   * \return Returns true if the packet should be forwarded up the

   * protocol stack.

   */

  bool ProcessHeader (Ptr<Packet> p, uint16_t & param);

private:

  /**

   * Operator = is declared but not implemented.  This disables the assigment

   * operator for CsmaNetDevice objects.

   */

  CsmaNetDevice &operator = (const CsmaNetDevice &o);

  /**

   * Copy constructor is declared but not implemented.  This disables the

   * copy constructor for CsmaNetDevice objects.

   */

  CsmaNetDevice (const CsmaNetDevice &o);

  /**

   * Initialization function used during object construction.

   */

  void Init (bool sendEnable, bool receiveEnable);

  /**

   * Calculate the value for the MAC-level MTU that would result from 

   * setting the PHY-level MTU to the given value.

   */

  uint16_t MacMtuFromPayload (uint16_t payloadLength);

  /**

   * Calculate the value for the PHY-level MTU that would be required

   * to be able to set the MAC-level MTU to the given value.

   */

  uint16_t PayloadFromMacMtu (uint16_t mtu);

  /**

   * Start Sending a Packet Down the Wire.

   *

   * The TransmitStart method is the method that is used internally in

   * the CsmaNetDevice to begin the process of sending a packet

   * out on the channel.  A corresponding method is called on the

   * channel to let it know that the physical device this class

   * represents has actually started sending signals, this causes the

   * channel to enter the BUSY state.  An event is scheduled for the time at

   * which the bits have been completely transmitted. 

   *

   * If the channel is found to be BUSY, this method reschedules itself for

   * execution at a later time (within the backoff period).

   *

   * \see CsmaChannel::TransmitStart ()

   * \see TransmitCompleteEvent ()

   */

  void TransmitStart ();

  /**

   * Stop Sending a Packet Down the Wire and Begin the Interframe Gap.

   *

   * The TransmitCompleteEvent method is used internally to finish the process

   * of sending a packet out on the channel.  During execution of this method

   * the TransmitEnd method is called on the channel to let it know that the

   * physical device this class represents has finished sending simulated

   * signals.  The channel uses this event to begin its speed of light delay

   * timer after which it notifies the Net Device(s) at the other end of the 

   * link that new bits have arrived (it delivers the Packet).  During this 

   * method, the net device also schedules the TransmitReadyEvent at which

   * time the transmitter becomes ready to send the next packet.

   *