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

/*

 * Copyright (c) 2007, 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

 */

#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 "ns3/pointer.h"

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

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

#include "ppp-header.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 MAC address of this device.",

                   Mac48AddressValue (Mac48Address ("ff:ff:ff:ff:ff:ff")),

                   MakeMac48AddressAccessor (&PointToPointNetDevice::m_address),

                   MakeMac48AddressChecker ())

    .AddAttribute ("DataRate", 

                   "The default data rate for point to point links",

                   DataRateValue (DataRate ("32768b/s")),

                   MakeDataRateAccessor (&PointToPointNetDevice::m_bps),

                   MakeDataRateChecker ())

    .AddAttribute ("ReceiveErrorModel", 

                   "The receiver error model used to simulate packet loss",

                   PointerValue (),

                   MakePointerAccessor (&PointToPointNetDevice::m_receiveErrorModel),

                   MakePointerChecker<ErrorModel> ())

    .AddAttribute ("TxQueue",

                   "A queue to use as the transmit queue in the device.",

                   PointerValue (),

                   MakePointerAccessor (&PointToPointNetDevice::m_queue),

                   MakePointerChecker<Queue> ())

    .AddAttribute ("InterframeGap", 

                   "The time to wait between packet (frame) transmissions",

                   TimeValue (Seconds (0.0)),

                   MakeTimeAccessor (&PointToPointNetDevice::m_tInterframeGap),

                   MakeTimeChecker ())

    .AddTraceSource ("Rx", 

                     "Trace source to fire on reception of a MAC packet.",

                     MakeTraceSourceAccessor (&PointToPointNetDevice::m_rxTrace))

    .AddTraceSource ("Drop",

                     "Trace source to fire on when a MAC packet is dropped.",

                     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 (this);

}

PointToPointNetDevice::~PointToPointNetDevice ()

{

}

  void 

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

{

  NS_LOG_FUNCTION_NOARGS ();

  NS_ASSERT_MSG (protocolNumber == 0x800,

    "PointToPointNetDevice::AddHeader(): protocolNumber must be 0x800");

  PppHeader ppp;

  p->AddHeader (ppp);

}

  bool 

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

{

  NS_LOG_FUNCTION_NOARGS ();

  PppHeader ppp;

  p->RemoveHeader (ppp);

  param = 0x800;

  return true;

}

  void 

PointToPointNetDevice::DoDispose()

{

  NS_LOG_FUNCTION_NOARGS ();

  m_node = 0;

  m_channel = 0;

  m_receiveErrorModel = 0;

  NetDevice::DoDispose ();

}

  void 

PointToPointNetDevice::SetDataRate(DataRate bps)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_bps = bps;

}

  void 

PointToPointNetDevice::SetInterframeGap(Time t)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_tInterframeGap = t;

}

  bool

PointToPointNetDevice::TransmitStart (Ptr<Packet> p)

{

  NS_LOG_FUNCTION (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");

  Simulator::Schedule (txCompleteTime, 

    &PointToPointNetDevice::TransmitComplete, this);

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

}

  void 

PointToPointNetDevice::TransmitComplete (void)

{

  NS_LOG_FUNCTION_NOARGS ();

//

// This function is called to when we're all done transmitting a packet.

// We try and pull another packet off of the transmit queue.  If the queue

// is empty, we are done, otherwise we need to start transmitting 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)

    {

//

// No packet was on the queue, so we just exit.

//

      return;

    }

//

// Got another packet off of the queue, so start the transmit process agin.

//

  TransmitStart(p);

}

  bool 

PointToPointNetDevice::Attach (Ptr<PointToPointChannel> ch)

{

  NS_LOG_FUNCTION (this << &ch);

  m_channel = ch;

  m_channel->Attach(this);

//

// This device is up whenever it is attached to a channel.  A better plan

// would be to have the link come up when both devices are attached, but this

// is not done for now.

//

  NotifyLinkUp ();

  return true;

}

  void

PointToPointNetDevice::SetQueue (Ptr<Queue> q)

{

  NS_LOG_FUNCTION (this << q);

  m_queue = q;

}

  void

PointToPointNetDevice::SetReceiveErrorModel (Ptr<ErrorModel> em)

{

  NS_LOG_FUNCTION (this << em);

  m_receiveErrorModel = em;

}

 void

PointToPointNetDevice::Receive (Ptr<Packet> packet)

{

  NS_LOG_FUNCTION (this << packet);

  uint16_t protocol = 0;

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

    {

// 

// If we have an error model and it indicates that it is time to lose a

// corrupted packet, don't forward this packet up, let it go.

//

      m_dropTrace (packet);

    }

  else 

    {

// 

// Hit the receive trace hook, strip off the point-to-point protocol header

// and forward this packet up the protocol stack.

//

      m_rxTrace (packet);

      ProcessHeader(packet, protocol);

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

    }

}

  Ptr<Queue> 

PointToPointNetDevice::GetQueue(void) const 

{ 

  NS_LOG_FUNCTION_NOARGS ();

  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;

}

//

// This is a point-to-point device, so we really don't need any kind of address

// information.  However, the base class NetDevice wants us to define the

// methods to get and set the address.  Rather than be rude and assert, we let

// clients get and set the address, but simply ignore them.

  void 

PointToPointNetDevice::SetAddress (Mac48Address addr)

{

  m_address = addr;

}

  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;

}

//

// This is a point-to-point device, so every transmission is a broadcast to

// all of the devices on the network.

//

  bool 

PointToPointNetDevice::IsBroadcast (void) const

{

  return true;

}

//

// We don't really need any addressing information since this is a 

// point-to-point device.  The base class NetDevice wants us to return a

// broadcast address, so we make up something reasonable.

//

  Address

PointToPointNetDevice::GetBroadcast (void) const

{

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

}

//

// We don't deal with multicast here.  It doesn't make sense to include some

// of the one destinations on the network but exclude some of the others.

//

  bool 

PointToPointNetDevice::IsMulticast (void) const

{

  return false;

}

//

// Since we return false in the IsMulticast call, calls to other multicast

// related methods returns are undefined according to the base class.  So we

// can freely make something up, which is the base of the MAC multicast

// address space.

//

  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_NOARGS ();

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

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

//

// If IsLinkUp() is false it means there is no channel to send any packet 

// over so we just return an error.

//

  if (IsLinkUp () == false)

    {

      return false;

    }

//

// Stick a point to point protocol header on the packet in preparation for

// shoving it out the door.

//

  AddHeader(packet, protocolNumber);

//

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

// transmission; otherwise we send it now.

//

  if (m_txMachineState == READY) 

    {

// 

// Even if the transmitter is immediately available, we still enqueue and 

// dequeue the packet to hit the tracing hooks.

//

      m_queue->Enqueue (packet);

      packet = m_queue->Dequeue ();

      return TransmitStart (packet);

    }

  else

    {

      return m_queue->Enqueue(packet);

    }

}

bool

PointToPointNetDevice::SendFrom (Ptr<Packet> packet, 

                                 const Address &source, 

                                 const Address &dest, 

                                 uint16_t protocolNumber)

{

  return Send (packet, dest, protocolNumber);

}

  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