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

/*

 * Copyright (c) 2007 Emmanuelle Laprise

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

 */

#include "ns3/log.h"

#include "ns3/queue.h"

#include "ns3/simulator.h"

#include "ns3/ethernet-header.h"

#include "ns3/ethernet-trailer.h"

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

#include "ns3/error-model.h"

#include "ns3/enum.h"

#include "ns3/boolean.h"

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

#include "csma-net-device.h"

#include "csma-channel.h"

NS_LOG_COMPONENT_DEFINE ("CsmaNetDevice");

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (CsmaNetDevice);

TypeId 

CsmaNetDevice::GetTypeId (void)

{

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

    .SetParent<NetDevice> ()

    .AddConstructor<CsmaNetDevice> ()

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

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

                   MakeMac48AddressAccessor (&CsmaNetDevice::m_address),

                   MakeMac48AddressChecker ())

    .AddAttribute ("EncapsulationMode", "The mode of link-layer encapsulation to use.",

                   Enum (LLC),

                   MakeEnumAccessor (&CsmaNetDevice::m_encapMode),

                   MakeEnumChecker (ETHERNET_V1, "EthernetV1",

                                    IP_ARP, "IpArp",

                                    RAW, "Raw",

                                    LLC, "Llc"))

    .AddAttribute ("SendEnable", "should tx be enabled ?",

                   Boolean (true),

                   MakeBooleanAccessor (&CsmaNetDevice::m_sendEnable),

                   MakeBooleanChecker ())

    .AddAttribute ("ReceiveEnable", "should rx be enabled ?",

                   Boolean (true),

                   MakeBooleanAccessor (&CsmaNetDevice::m_receiveEnable),

                   MakeBooleanChecker ())

    .AddAttribute ("DataRate", "XXX",

                   DataRate (0xffffffff),

                   MakeDataRateAccessor (&CsmaNetDevice::m_bps),

                   MakeDataRateChecker ())

    .AddAttribute ("RxErrorModel", "XXX",

                   Ptr<ErrorModel> (0),

                   MakePtrAccessor (&CsmaNetDevice::m_receiveErrorModel),

                   MakePtrChecker<ErrorModel> ())

    .AddAttribute ("TxQueue", "XXX",

                   Ptr<Queue> (0),

                   MakePtrAccessor (&CsmaNetDevice::m_queue),

                   MakePtrChecker<Queue> ())

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

                     MakeTraceSourceAccessor (&CsmaNetDevice::m_rxTrace))

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

                     MakeTraceSourceAccessor (&CsmaNetDevice::m_dropTrace))

    ;

  return tid;

}

CsmaNetDevice::CsmaNetDevice ()

  : m_name (""),

    m_linkUp (false),

    m_mtu (0xffff)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this);

  m_txMachineState = READY;

  m_tInterframeGap = Seconds(0);

  m_channel = 0; 

}

CsmaNetDevice::~CsmaNetDevice()

{

  NS_LOG_FUNCTION;

  m_queue = 0;

}

void 

CsmaNetDevice::DoDispose ()

{

  NS_LOG_FUNCTION;

  m_channel = 0;

  m_node = 0;

  NetDevice::DoDispose ();

}

void 

CsmaNetDevice::SetAddress (Mac48Address self)

{

  m_address = self;

}

void

CsmaNetDevice::SetSendEnable (bool sendEnable)

{

  NS_LOG_FUNCTION;

  m_sendEnable = sendEnable;

}

void

CsmaNetDevice::SetReceiveEnable (bool receiveEnable)

{

  NS_LOG_FUNCTION;

  m_receiveEnable = receiveEnable;

}

bool

CsmaNetDevice::IsSendEnabled (void)

{

  NS_LOG_FUNCTION;

  return (m_sendEnable);

}

bool

CsmaNetDevice::IsReceiveEnabled (void)

{

  NS_LOG_FUNCTION;

  return (m_receiveEnable);

}

void 

CsmaNetDevice::SetDataRate (DataRate bps)

{

  NS_LOG_FUNCTION;

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

    {

      m_bps = bps;

    }

}

void 

CsmaNetDevice::SetInterframeGap (Time t)

{

  NS_LOG_FUNCTION;

  m_tInterframeGap = t;

}

void 

CsmaNetDevice::SetBackoffParams (Time slotTime, uint32_t minSlots, 

                                 uint32_t maxSlots, uint32_t ceiling, 

                                 uint32_t maxRetries)

{

  NS_LOG_FUNCTION;

  m_backoff.m_slotTime = slotTime;

  m_backoff.m_minSlots = minSlots;

  m_backoff.m_maxSlots = maxSlots;

  m_backoff.m_ceiling = ceiling;

  m_backoff.m_maxRetries = maxRetries;

}

void 

CsmaNetDevice::AddHeader (Ptr<Packet> p, Mac48Address dest,

                            uint16_t protocolNumber)

{

  NS_LOG_FUNCTION;

  if (m_encapMode == RAW)

    {

      return;

    }

  EthernetHeader header (false);

  EthernetTrailer trailer;

  Mac48Address source = Mac48Address::ConvertFrom (GetAddress ());

  header.SetSource(source);

  header.SetDestination(dest);

  uint16_t lengthType = 0;

  switch (m_encapMode) 

    {

    case ETHERNET_V1:

      lengthType = p->GetSize() + header.GetSerializedSize() + trailer.GetSerializedSize();

      break;

    case IP_ARP:

      lengthType = protocolNumber;

      break;

    case LLC: {

      LlcSnapHeader llc;

      llc.SetType (protocolNumber);

      p->AddHeader (llc);

    } break;

    case RAW:

      NS_ASSERT (false);

      break;

    }

  header.SetLengthType (lengthType);

  p->AddHeader(header);

  trailer.CalcFcs(p);

  p->AddTrailer(trailer);

}

bool 

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

{

  NS_LOG_FUNCTION;

  if (m_encapMode == RAW)

    {

      return true;

    }

  EthernetHeader header (false);

  EthernetTrailer trailer;

  p->RemoveTrailer(trailer);

  trailer.CheckFcs(p);

  p->RemoveHeader(header);

  if ((header.GetDestination() != GetBroadcast ()) &&

      (header.GetDestination() != GetAddress ()))

    {

      return false;

    }

  switch (m_encapMode)

    {

    case ETHERNET_V1:

    case IP_ARP:

      param = header.GetLengthType();

      break;

    case LLC: {

      LlcSnapHeader llc;

      p->RemoveHeader (llc);

      param = llc.GetType ();

    } break;

    case RAW:

      NS_ASSERT (false);

      break;

    }

  return true;

}

void

CsmaNetDevice::TransmitStart ()

{

  NS_LOG_FUNCTION;

  NS_LOG_LOGIC ("m_currentPkt=" << m_currentPkt);

  NS_LOG_LOGIC ("UID is " << m_currentPkt->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 it's time to tell the 

// channel that we're done wiggling the wire.

//

  NS_ASSERT_MSG((m_txMachineState == READY) || (m_txMachineState == BACKOFF), 

                "Must be READY to transmit. Tx state is: " 

                << m_txMachineState);

  // Only transmit if send side of net device is enabled

  if (!IsSendEnabled())

    return;

  if (m_channel->GetState() != IDLE)

    { // Channel busy, backoff and rechedule TransmitStart()

      m_txMachineState = BACKOFF;

      if (m_backoff.MaxRetriesReached())

        { // Too many retries reached, abort transmission of packet

          TransmitAbort();

        } 

      else 

        {

          m_backoff.IncrNumRetries();

          Time backoffTime = m_backoff.GetBackoffTime();

          NS_LOG_LOGIC ("Channel busy, backing off for " << 

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

          Simulator::Schedule (backoffTime, 

                               &CsmaNetDevice::TransmitStart, 

                               this);

        }

    } 

  else 

    {

      // Channel is free, transmit packet

      m_txMachineState = BUSY;

      Time tEvent = Seconds (m_bps.CalculateTxTime(m_currentPkt->GetSize()));

      NS_LOG_LOGIC ("Schedule TransmitCompleteEvent in " << 

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

      Simulator::Schedule (tEvent, 

                           &CsmaNetDevice::TransmitCompleteEvent, 

                           this);

      if (!m_channel->TransmitStart (m_currentPkt, m_deviceId))

        {

          NS_LOG_WARN ("Channel transmit start did not work at " << 

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

          m_txMachineState = READY;

        } 

      else 

        {

          // Transmission success, reset backoff time parameters.

          m_backoff.ResetBackoffTime();

        }

    }

}

void

CsmaNetDevice::TransmitAbort (void)

{

  NS_LOG_FUNCTION;

  NS_LOG_LOGIC ("Pkt UID is " << m_currentPkt->GetUid () << ")");

  // Try to transmit a new packet

  m_currentPkt = m_queue->Dequeue ();

  NS_ASSERT_MSG(m_currentPkt != 0, "IsEmpty false but no Packet on queue?");

  m_backoff.ResetBackoffTime();

  m_txMachineState = READY;

  TransmitStart ();

}

void

CsmaNetDevice::TransmitCompleteEvent (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

// schedule an event that will be executed when it's time to re-enable

// the transmitter after the interframe gap.

//

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

  // Channel should be transmitting

  NS_ASSERT(m_channel->GetState() == TRANSMITTING);

  m_txMachineState = GAP;

  NS_LOG_LOGIC ("Pkt UID is " << m_currentPkt->GetUid () << ")");

  m_channel->TransmitEnd (); 

  NS_LOG_LOGIC ("Schedule TransmitReadyEvent in "

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

  Simulator::Schedule (m_tInterframeGap, 

                       &CsmaNetDevice::TransmitReadyEvent, 

                       this);

}

void

CsmaNetDevice::TransmitReadyEvent (void)

{

  NS_LOG_FUNCTION;

//

// This function is called to enable the transmitter after the interframe

// gap has passed.  If there are pending transmissions, we use this opportunity

// to start the next transmit.

//

  NS_ASSERT_MSG(m_txMachineState == GAP, "Must be in interframe gap");

  m_txMachineState = READY;

  // Get the next packet from the queue for transmitting

  if (m_queue->IsEmpty())

    {

      return;

    }

  else

    {

      m_currentPkt = m_queue->Dequeue ();

      NS_ASSERT_MSG(m_currentPkt != 0, "IsEmpty false but no Packet on queue?");

      TransmitStart ();

    }

}

bool

CsmaNetDevice::Attach (Ptr<CsmaChannel> ch)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << &ch);

  m_channel = ch;

  m_deviceId = m_channel->Attach(this);

  m_bps = m_channel->GetDataRate ();

  m_tInterframeGap = m_channel->GetDelay ();

  /* 

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

   */

  NotifyLinkUp ();

  return true;

}

void

CsmaNetDevice::AddQueue (Ptr<Queue> q)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << q);

  m_queue = q;

}

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

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAM ("(" << em << ")");

  m_receiveErrorModel = em; 

}

void

CsmaNetDevice::Receive (Ptr<Packet> packet)

{

  NS_LOG_FUNCTION;

  EthernetHeader header (false);

  EthernetTrailer trailer;

  Mac48Address broadcast;

  Mac48Address multicast;

  Mac48Address destination;

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

  // Only receive if send side of net device is enabled

  if (!IsReceiveEnabled())

    {

      m_dropTrace (packet);

      return;

    }

  if (m_encapMode == RAW)

    {

      m_rxCallback (this, packet, 0, GetBroadcast ());

      m_dropTrace (packet);

      return;

    }

  packet->RemoveTrailer(trailer);

  trailer.CheckFcs(packet);

  packet->RemoveHeader(header);

  NS_LOG_LOGIC ("Pkt destination is " << header.GetDestination ());

//

// An IP 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).

//

// We are going to receive all packets destined to any multicast address,

// which means clearing the low-order 23 bits the header destination 

//

  Mac48Address mcDest;

  uint8_t      mcBuf[6];

  header.GetDestination ().CopyTo (mcBuf);

  mcBuf[3] &= 0x80;

  mcBuf[4] = 0;

  mcBuf[5] = 0;

  mcDest.CopyFrom (mcBuf);

  multicast = Mac48Address::ConvertFrom (GetMulticast ());

  broadcast = Mac48Address::ConvertFrom (GetBroadcast ());

  destination = Mac48Address::ConvertFrom (GetAddress ());

  if ((header.GetDestination () != broadcast) &&

      (mcDest != multicast) &&

      (header.GetDestination () != destination))

    {

      NS_LOG_LOGIC ("Dropping pkt ");

      m_dropTrace (packet);

      return;

    }

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

    {

      NS_LOG_LOGIC ("Dropping pkt due to error model ");

      m_dropTrace (packet);

      // Do not forward up; let this packet go

    }

  else

    {