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

/*

 * Copyright (c) 2006 INRIA

 *

 * 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: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

 */

#include "ns3/assert.h"

#include "ns3/packet.h"

#include "ns3/simulator.h"

#include "arp-cache.h"

#include "arp-header.h"

#include "ipv4-interface.h"

namespace ns3 {

ArpCache::ArpCache (Ptr<NetDevice> device, Ptr<Ipv4Interface> interface)

  : m_device (device), 

    m_interface (interface),

    m_aliveTimeout (Seconds (120)),

    m_deadTimeout (Seconds (100)),

    m_waitReplyTimeout (Seconds (1))

{}

ArpCache::~ArpCache ()

{

  Flush ();

}

Ptr<NetDevice>

ArpCache::GetDevice (void) const

{

  return m_device;

}

Ptr<Ipv4Interface>

ArpCache::GetInterface (void) const

{

  return m_interface;

}

void 

ArpCache::SetAliveTimeout (Time aliveTimeout)

{

  m_aliveTimeout = aliveTimeout;

}

void 

ArpCache::SetDeadTimeout (Time deadTimeout)

{

  m_deadTimeout = deadTimeout;

}

void 

ArpCache::SetWaitReplyTimeout (Time waitReplyTimeout)

{

  m_waitReplyTimeout = waitReplyTimeout;

}

Time

ArpCache::GetAliveTimeout (void) const

{

  return m_aliveTimeout;

}

Time

ArpCache::GetDeadTimeout (void) const

{

  return m_deadTimeout;

}

Time

ArpCache::GetWaitReplyTimeout (void) const

{

  return m_waitReplyTimeout;

}

void 

ArpCache::Flush (void)

{

  for (CacheI i = m_arpCache.begin (); i != m_arpCache.end (); i++) 

    {

      delete (*i).second;

    }

  m_arpCache.erase (m_arpCache.begin (), m_arpCache.end ());

}

ArpCache::Entry *

ArpCache::Lookup (Ipv4Address to)

{

  if (m_arpCache.find (to) != m_arpCache.end ()) 

    {

      ArpCache::Entry *entry = m_arpCache[to];

      return entry;

    }

  return 0;

}

ArpCache::Entry *

ArpCache::Add (Ipv4Address to)

{

  NS_ASSERT (m_arpCache.find (to) == m_arpCache.end ());

  ArpCache::Entry *entry = new ArpCache::Entry (this);

  m_arpCache[to] = entry;  

  return entry;

}

ArpCache::Entry::Entry (ArpCache *arp)

  : m_arp (arp),

    m_state (ALIVE),

    m_waiting ()

{}

bool 

ArpCache::Entry::IsDead (void)

{

  return (m_state == DEAD)?true:false;

}

bool 

ArpCache::Entry::IsAlive (void)

{

  return (m_state == ALIVE)?true:false;

}

bool

ArpCache::Entry::IsWaitReply (void)

{

  return (m_state == WAIT_REPLY)?true:false;

}

void 

ArpCache::Entry::MarkDead (void) 

{

  m_state = DEAD;

  //NS_ASSERT (m_waiting != 0);

  UpdateSeen ();

}

Ptr<Packet>

ArpCache::Entry::MarkAlive (Address macAddress) 

{

  NS_ASSERT (m_state == WAIT_REPLY);

  //NS_ASSERT (m_waiting != 0);

  m_macAddress = macAddress;

  m_state = ALIVE;

  UpdateSeen ();

  Ptr<Packet> waiting = m_waiting;

  //m_waiting = 0;

  return waiting;

}

Ptr<Packet>

ArpCache::Entry::UpdateWaitReply (Ptr<Packet> waiting)

{

  NS_ASSERT (m_state == WAIT_REPLY);

  /* We are already waiting for an answer so

   * we dump the previously waiting packet and

   * replace it with this one.

   */

  Ptr<Packet> old = m_waiting;

  m_waiting = waiting;

  return old;

}

void 

ArpCache::Entry::MarkWaitReply (Ptr<Packet> waiting)

{

  NS_ASSERT (m_state == ALIVE || m_state == DEAD);

  //NS_ASSERT (m_waiting == 0);

  m_state = WAIT_REPLY;

  m_waiting = waiting;

  UpdateSeen ();

}

Address

ArpCache::Entry::GetMacAddress (void)

{

  NS_ASSERT (m_state == ALIVE);

  return m_macAddress;

}

bool 

ArpCache::Entry::IsExpired (void)

{

  Time timeout;

  switch (m_state) {

  case ArpCache::Entry::WAIT_REPLY:

    timeout = m_arp->GetWaitReplyTimeout ();

    break;

  case ArpCache::Entry::DEAD:

    timeout = m_arp->GetDeadTimeout ();

    break;

  case ArpCache::Entry::ALIVE:

    timeout = m_arp->GetAliveTimeout ();

    break;

  default:

    NS_ASSERT (false);

    timeout = Seconds (0);

    /* NOTREACHED */

    break;

  }

  Time delta = Simulator::Now () - m_lastSeen;

  if (delta >= timeout) 

    {

      return true;

    } 

  else 

    {

      return false;

    }

}

void 

ArpCache::Entry::UpdateSeen (void)

{

  m_lastSeen = Simulator::Now ();

}

} // namespace ns3