text: /* -*- 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 <cstring>
  #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/mac48-address.h"
  
  namespace ns3 {
  
  class Queue;
  class CsmaChannel;
  class ErrorModel;
  
  /** 
   * \defgroup csma CSMA Network Device
   *
   * This section documents the API of the ns-3 csma module. For a generic functional description, please refer to the ns-3 manual.
   */
  
  /**
   * \ingroup csma
   * \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. 
   */
  class CsmaNetDevice : 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 CsmaNetDevice
     *
     * This is the default constructor for a CsmaNetDevice.
     */
    CsmaNetDevice ();
  
    /**
     * Destroy a CsmaNetDevice
     *
     * This is the destructor for a CsmaNetDevice.
     */
    virtual ~CsmaNetDevice ();
  
    /**
     * Set the interframe 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);
  
    /**
     * Get a copy of the attached Queue.
     *
     * \return a pointer to the queue.
     */
    Ptr<Queue> GetQueue (void) const; 
  
    /**
     * 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 encapsulation mode of this device.
     *
     * \param mode The encapsulation mode of this device.
     *
     */
    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 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 void SetAddress (Address address);
    virtual Address GetAddress (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;
  
    /**
     * 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;
  
    /**
     * Start sending a packet down the channel.
     * \param packet packet to send
     * \param dest layer 2 destination address
     * \param protocolNumber protocol number
     * \return true if successfull, false otherwise (drop, ...)
     */
    virtual bool Send (Ptr<Packet> packet, const Address& dest, 
                       uint16_t protocolNumber);
  
    /**
     * Start sending a packet down the channel, with MAC spoofing
     * \param packet packet to send
     * \param source layer 2 source address
     * \param dest layer 2 destination address
     * \param protocolNumber protocol number
     * \return true if successfull, false otherwise (drop, ...)
     */
    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);
  
    /**
     * \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;
  
  
    virtual void SetPromiscReceiveCallback (PromiscReceiveCallback cb);
    virtual bool SupportsSendFrom (void) const;
  
   /**
    * Assign a fixed random variable stream number to the random variables
    * used by this model.  Return the number of streams (possibly zero) that
    * have been assigned.
    *
    * \param stream first stream index to use
    * \return the number of stream indices assigned by this model
    */
    int64_t AssignStreams (int64_t stream);
  
  protected:
    /**
     * Perform any object release functionality required to break reference 
     * cycles in reference counted objects held by the device.
     */
    virtual void DoDispose (void);
  
    /**
     * 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 source MAC source address from which packet should be sent
     * \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);
  
  private:
  
    /**
     * Operator = is declared but not implemented.  This disables the assignment
     * operator for CsmaNetDevice objects.
     * \param o object to copy
     */
    CsmaNetDevice &operator = (const CsmaNetDevice &o);
  
    /**
     * Copy constructor is declared but not implemented.  This disables the
     * copy constructor for CsmaNetDevice objects.
     * \param o object to copy
     */
    CsmaNetDevice (const CsmaNetDevice &o);
  
    /**
     * Initialization function used during object construction.
     * \param sendEnable if device will be allowed to send
     * \param receiveEnable if device will be allowed to receive
     */
    void Init (bool sendEnable, bool receiveEnable);
  
    /**
     * 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.
     *
     * \see CsmaChannel::TransmitEnd ()
     * \see TransmitReadyEvent ()
     */
    void TransmitCompleteEvent (void);
  
    /**
     * Cause the Transmitter to Become Ready to Send Another Packet.
     *
     * The TransmitReadyEvent method is used internally to re-enable the 
     * transmit machine of the net device.  It is scheduled after a suitable
     * interframe gap after the completion of the previous transmission.
     * The queue is checked at this time, and if there is a packet waiting on
     * the queue, the transmission process is begun.
     *
     * If a packet is in the queue, it is extracted for the queue as the
     * next packet to be transmitted by the net device.
     *
     * \see TransmitStart ()
     */
    void TransmitReadyEvent (void);
  
    /**
     * Aborts the transmission of the current packet
     *
     * If the net device has tried to transmit a packet for more times
     * than the maximum allowed number of retries (channel always busy)
     * then the packet is dropped.
     */
    void TransmitAbort (void);
  
    /**
     * Notify any interested parties that the link has come up.
     */
    void NotifyLinkUp (void);
  
    /** 
     * Device ID returned by the attached functions. It is used by the
     * mp-channel to identify each net device to make sure that only
     * active net devices are writing to the channel
     */
    uint32_t m_deviceId; 
  
    /**
     * Enable net device to send packets. True by default
     */
    bool m_sendEnable;
  
    /**
     * Enable net device to receive packets. True by default
     */
    bool m_receiveEnable;
  
    /**
     * 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 */
      GAP,      /**< The transmitter is in the interframe gap time */
      BACKOFF      /**< The transmitter is waiting for the channel to be free */
    };
  
    /**
     * The state of the Net Device transmit state machine.
     * \see TxMachineState
     */
    TxMachineState m_txMachineState;
  
    /**
     * The type of packet that should be created by the AddHeader
     * function and that should be processed by the ProcessHeader
     * function.
     */
    EncapsulationMode m_encapMode;
  
    /**
     * 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 insert time between packet
     * transmission
     * \see class Time
     */
    Time m_tInterframeGap;
  
    /**
     * Holds the backoff parameters and is used to calculate the next
     * backoff time to use when the channel is busy and the net device
     * is ready to transmit
     */
    Backoff m_backoff;
  
    /**
     * Next packet that will be transmitted (if transmitter is not
     * currently transmitting) or packet that is currently being
     * transmitted.
     */
    Ptr<Packet> m_currentPkt;
  
    /**
     * The CsmaChannel to which this CsmaNetDevice has been
     * attached.
     * \see class CsmaChannel
     */
    Ptr<CsmaChannel> m_channel;
  
    /**
     * The Queue which this CsmaNetDevice uses as a packet source.
     * Management of this Queue has been delegated to the CsmaNetDevice
     * and it has the responsibility for deletion.
     * \see class Queue
     * \see class DropTailQueue
     */
    Ptr<Queue> m_queue;
  
    /**
     * Error model for receive packet events.  When active this model will be
     * used to model transmission errors by marking some of the packets 
     * received as corrupt.
     */
    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.
     *
     * \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 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 mac layer is forced to begin the backoff
     * process for a packet.  This can happen a number of times as the backoff
     * sequence is repeated with increasing delays.
     *
     * \see class CallBackTraceSource
     */
    TracedCallback<Ptr<const Packet> > m_macTxBackoffTrace;
  
    /**
     * 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 begins the reception process from
     * the medium.
     *
     * \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.
     *
     * \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;
  
    /**
     * 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 interface index (really net evice index) that has been assigned to 
     * this network device.
     */
    uint32_t m_ifIndex;
  
    /**
     * 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;
  
    /**
     * List of callbacks to fire if the link changes state (up or down).
     */
    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;
  };
  
  } // namespace ns3
  
  #endif /* CSMA_NET_DEVICE_H */
  