/* -*- 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:  Craig Dowell <craigdo@ee.washington.edu>

 * Revised: George Riley <riley@ece.gatech.edu>

 */

#include "ns3/log.h"

#include "ns3/queue.h"

#include "ns3/simulator.h"

#include "ns3/mac48-address.h"

#include "ns3/llc-snap-header.h"

#include "ns3/error-model.h"

#include "ns3/trace-source-accessor.h"

#include "point-to-point-net-device.h"

#include "point-to-point-channel.h"

NS_LOG_COMPONENT_DEFINE ("PointToPointNetDevice");

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (PointToPointNetDevice);

TypeId 

PointToPointNetDevice::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::PointToPointNetDevice")

    .SetParent<NetDevice> ()

    .AddConstructor<PointToPointNetDevice> ()

    .AddAttribute ("Address", "The address of this device.",

                   Mac48Address ("ff:ff:ff:ff:ff:ff"),

                   MakeMac48AddressAccessor (&PointToPointNetDevice::m_address),

                   MakeMac48AddressChecker ())

    .AddAttribute ("DataRate", "The default data rate for point to point links",

                   DataRate ("10Mb/s"),

                   MakeDataRateAccessor (&PointToPointNetDevice::m_bps),

                   MakeDataRateChecker ())

                   Ptr<ErrorModel> (0),

                   MakePtrAccessor (&PointToPointNetDevice::m_receiveErrorModel),

                   MakePtrChecker<ErrorModel> ())

    .AddAttribute ("TxQueue", "XXX",

                   Ptr<Queue> (0),

                   MakePtrAccessor (&PointToPointNetDevice::m_queue),

                   MakePtrChecker<Queue> ())

    .AddAttribute ("InterframeGap", "XXX",

                   Seconds (0.0),

                   MakeTimeAccessor (&PointToPointNetDevice::m_tInterframeGap),

                   MakeTimeChecker ())

    .AddTraceSource ("Rx", "Receive MAC packet.",

                     MakeTraceSourceAccessor (&PointToPointNetDevice::m_rxTrace))

    .AddTraceSource ("Drop", "Drop MAC packet.",

                     MakeTraceSourceAccessor (&PointToPointNetDevice::m_dropTrace))

    ;

  return tid;

}

PointToPointNetDevice::PointToPointNetDevice () 

: 

  m_txMachineState (READY),

  m_channel (0), 

  m_name (""),

  m_linkUp (false),

  m_mtu (0xffff)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this);

}

PointToPointNetDevice::~PointToPointNetDevice ()

{}

void 

PointToPointNetDevice::SetAddress (Mac48Address self)

{

  m_address = self;

}

void 

PointToPointNetDevice::AddHeader(Ptr<Packet> p, uint16_t protocolNumber)

{

  NS_LOG_FUNCTION;

  LlcSnapHeader llc;

  llc.SetType (protocolNumber);

  p->AddHeader (llc);

}

bool 

PointToPointNetDevice::ProcessHeader(Ptr<Packet> p, uint16_t& param)

{

  NS_LOG_FUNCTION;

  LlcSnapHeader llc;

  p->RemoveHeader (llc);

  param = llc.GetType ();

  return true;

}

void PointToPointNetDevice::DoDispose()

{

  NS_LOG_FUNCTION;

  m_node = 0;

  m_channel = 0;

  m_receiveErrorModel = 0;

  NetDevice::DoDispose ();

}

void PointToPointNetDevice::SetDataRate(const DataRate& bps)

{

  NS_LOG_FUNCTION;

  if (!m_channel || bps <= m_channel->GetDataRate ())

    {

      m_bps = bps;

    }

}

void PointToPointNetDevice::SetInterframeGap(const Time& t)

{

  NS_LOG_FUNCTION;

  m_tInterframeGap = t;

}

bool

PointToPointNetDevice::TransmitStart (Ptr<Packet> p)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << p);

  NS_LOG_LOGIC ("UID is " << p->GetUid () << ")");

//

// This function is called to start the process of transmitting a packet.

// We need to tell the channel that we've started wiggling the wire and

// schedule an event that will be executed when the transmission is complete.

//

  NS_ASSERT_MSG(m_txMachineState == READY, "Must be READY to transmit");

  m_txMachineState = BUSY;

  Time txTime = Seconds (m_bps.CalculateTxTime(p->GetSize()));

  Time txCompleteTime = txTime + m_tInterframeGap;

  NS_LOG_LOGIC ("Schedule TransmitCompleteEvent in " << 

    txCompleteTime.GetSeconds () << "sec");

  // Schedule the tx complete event

  Simulator::Schedule (txCompleteTime, 

                       &PointToPointNetDevice::TransmitComplete, 

                       this);

  return m_channel->TransmitStart(p, this, txTime); 

}

void PointToPointNetDevice::TransmitComplete (void)

{

  NS_LOG_FUNCTION;

//

// This function is called to finish the  process of transmitting a packet.

// We need to tell the channel that we've stopped wiggling the wire and

// get the next packet from the queue.  If the queue is empty, we are

// done, otherwise transmit the next packet.

//

  NS_ASSERT_MSG(m_txMachineState == BUSY, "Must be BUSY if transmitting");

  m_txMachineState = READY;

  Ptr<Packet> p = m_queue->Dequeue ();

  if (p == 0)

    {

      return; // Nothing to do at this point

    }

  TransmitStart(p);

}

bool 

PointToPointNetDevice::Attach (Ptr<PointToPointChannel> ch)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << &ch);

  m_channel = ch;

  m_channel->Attach(this);

  m_bps = m_channel->GetDataRate ();

  // GFR Comment.  Below is definitely wrong.  Interframe gap

  // is unrelated to channel delay.

  // -- unlesss you want to introduce a default gap which is there to avoid

  // parts of multiple packets flowing on the "wire" at the same time.

  //m_tInterframeGap = m_channel->GetDelay ();

  /* 

   * For now, this device is up whenever a channel is attached to it.

   * In fact, it should become up only when the second device

   * is attached to the channel. So, there should be a way for

   * a PointToPointChannel to notify both of its attached devices

   * that the channel is 'complete', hence that the devices are

   * up, hence that they can call NotifyLinkUp. 

   */

  NotifyLinkUp ();

  return true;

}

void PointToPointNetDevice::AddQueue (Ptr<Queue> q)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << q);

  m_queue = q;

}

void PointToPointNetDevice::AddReceiveErrorModel (Ptr<ErrorModel> em)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS ("(" << em << ")");

  m_receiveErrorModel = em;

}

void PointToPointNetDevice::Receive (Ptr<Packet> packet)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << packet);

  uint16_t protocol = 0;

  if (m_receiveErrorModel && m_receiveErrorModel->IsCorrupt (packet) ) 

    {

      m_dropTrace (packet);

      // Do not forward up; let this packet go

    }

  else 

    {

      m_rxTrace (packet);

      ProcessHeader(packet, protocol);

      m_rxCallback (this, packet, protocol, GetBroadcast ());

    }

}

Ptr<Queue> PointToPointNetDevice::GetQueue(void) const 

{ 

  NS_LOG_FUNCTION;

  return m_queue;

}

void

PointToPointNetDevice::NotifyLinkUp (void)

{

  m_linkUp = true;

  if (!m_linkChangeCallback.IsNull ())

    {

      m_linkChangeCallback ();

    }

}

void 

PointToPointNetDevice::SetName(const std::string name)

{

  m_name = name;

}

std::string 

PointToPointNetDevice::GetName(void) const

{

  return m_name;

}

void 

PointToPointNetDevice::SetIfIndex(const uint32_t index)

{

  m_ifIndex = index;

}

uint32_t 

PointToPointNetDevice::GetIfIndex(void) const

{

  return m_ifIndex;

}

Ptr<Channel> 

PointToPointNetDevice::GetChannel (void) const

{

  return m_channel;

}

Address 

PointToPointNetDevice::GetAddress (void) const

{

  return m_address;

}

bool 

PointToPointNetDevice::SetMtu (const uint16_t mtu)

{

  m_mtu = mtu;

  return true;

}

uint16_t 

PointToPointNetDevice::GetMtu (void) const

{

  return m_mtu;

}

bool 

PointToPointNetDevice::IsLinkUp (void) const

{

  return m_linkUp;

}

void 

PointToPointNetDevice::SetLinkChangeCallback (Callback<void> callback)

{

  m_linkChangeCallback = callback;

}

bool 

PointToPointNetDevice::IsBroadcast (void) const

{

  return true;

}

Address

PointToPointNetDevice::GetBroadcast (void) const

{

  return Mac48Address ("ff:ff:ff:ff:ff:ff");

}

bool 

PointToPointNetDevice::IsMulticast (void) const

{

  return false;

}

Address 

PointToPointNetDevice::GetMulticast (void) const

{

  return Mac48Address ("01:00:5e:00:00:00");

}

Address 

PointToPointNetDevice::MakeMulticastAddress (Ipv4Address multicastGroup) const

{

  return Mac48Address ("01:00:5e:00:00:00");

}

bool 

PointToPointNetDevice::IsPointToPoint (void) const

{

  return true;

}

bool 

PointToPointNetDevice::Send(Ptr<Packet> packet, const Address& dest, uint16_t protocolNumber)

{

    NS_LOG_FUNCTION;

  NS_LOG_LOGIC ("p=" << packet << ", dest=" << &dest);

  NS_LOG_LOGIC ("UID is " << packet->GetUid ());

  // GFR Comment. Why is this an assertion? Can't a link legitimately

  // "go down" during the simulation?  Shouldn't we just wait for it

  // to come back up?

  NS_ASSERT (IsLinkUp ());

  AddHeader(packet, protocolNumber);

//

// This class simulates a point to point device.  In the case of a serial

// link, this means that we're simulating something like a UART.

//

//

// If there's a transmission in progress, we enque the packet for later

// transmission; otherwise we send it now.

  if (m_txMachineState == READY) 

    {

// We still enqueue and dequeue it to hit the tracing hooks

      m_queue->Enqueue (packet);

      packet = m_queue->Dequeue ();

      return TransmitStart (packet);

    }

  else

    {

      return m_queue->Enqueue(packet);

    }

}

Ptr<Node> 

PointToPointNetDevice::GetNode (void) const

{

  return m_node;

}

void 

PointToPointNetDevice::SetNode (Ptr<Node> node)

{

  m_node = node;

}

bool 

PointToPointNetDevice::NeedsArp (void) const

{

  return false;

}

void 

PointToPointNetDevice::SetReceiveCallback (NetDevice::ReceiveCallback cb)

{

  m_rxCallback = cb;

}

} // namespace ns3