text: /* -*- 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 "ns3/uinteger.h"
  #include "ns3/log.h"
  #include "ns3/node.h"
  #include "ns3/trace-source-accessor.h"
  #include "ns3/names.h"
  
  #include "arp-cache.h"
  #include "arp-header.h"
  #include "ipv4-interface.h"
  
  namespace ns3 {
  
  NS_LOG_COMPONENT_DEFINE ("ArpCache");
  
  NS_OBJECT_ENSURE_REGISTERED (ArpCache);
  
  TypeId 
  ArpCache::GetTypeId (void)
  {
    static TypeId tid = TypeId ("ns3::ArpCache")
      .SetParent<Object> ()
      .AddAttribute ("AliveTimeout",
                     "When this timeout expires, "
                     "the matching cache entry needs refreshing",
                     TimeValue (Seconds (120)),
                     MakeTimeAccessor (&ArpCache::m_aliveTimeout),
                     MakeTimeChecker ())
      .AddAttribute ("DeadTimeout",
                     "When this timeout expires, "
                     "a new attempt to resolve the matching entry is made",
                     TimeValue (Seconds (100)),
                     MakeTimeAccessor (&ArpCache::m_deadTimeout),
                     MakeTimeChecker ())
      .AddAttribute ("WaitReplyTimeout",
                     "When this timeout expires, "
                     "the cache entries will be scanned and "
                     "entries in WaitReply state will resend ArpRequest "
                     "unless MaxRetries has been exceeded, "
                     "in which case the entry is marked dead",
                     TimeValue (Seconds (1)),
                     MakeTimeAccessor (&ArpCache::m_waitReplyTimeout),
                     MakeTimeChecker ())
      .AddAttribute ("MaxRetries",
                     "Number of retransmissions of ArpRequest "
                     "before marking dead",
                     UintegerValue (3),
                     MakeUintegerAccessor (&ArpCache::m_maxRetries),
                     MakeUintegerChecker<uint32_t> ())
      .AddAttribute ("PendingQueueSize",
                     "The size of the queue for packets pending an arp reply.",
                     UintegerValue (3),
                     MakeUintegerAccessor (&ArpCache::m_pendingQueueSize),
                     MakeUintegerChecker<uint32_t> ())
      .AddTraceSource ("Drop",
                       "Packet dropped due to ArpCache entry "
                       "in WaitReply expiring.",
                       MakeTraceSourceAccessor (&ArpCache::m_dropTrace),
                       "ns3::Packet::TracedCallback")
    ;
    return tid;
  }
  
  ArpCache::ArpCache ()
    : m_device (0), 
      m_interface (0)
  {
    NS_LOG_FUNCTION (this);
  }
  
  ArpCache::~ArpCache ()
  {
    NS_LOG_FUNCTION (this);
  }
  
  void 
  ArpCache::DoDispose (void)
  {
    NS_LOG_FUNCTION (this);
    Flush ();
    m_device = 0;
    m_interface = 0;
    if (!m_waitReplyTimer.IsRunning ())
      {
        Simulator::Remove (m_waitReplyTimer);
      }
    Object::DoDispose ();
  }
  
  void
  ArpCache::SetDevice (Ptr<NetDevice> device, Ptr<Ipv4Interface> interface)
  {
    NS_LOG_FUNCTION (this << device << interface);
    m_device = device;
    m_interface = interface;
  }
  
  Ptr<NetDevice>
  ArpCache::GetDevice (void) const
  {
    NS_LOG_FUNCTION (this);
    return m_device;
  }
  
  Ptr<Ipv4Interface>
  ArpCache::GetInterface (void) const
  {
    NS_LOG_FUNCTION (this);
    return m_interface;
  }
  
  void 
  ArpCache::SetAliveTimeout (Time aliveTimeout)
  {
    NS_LOG_FUNCTION (this << aliveTimeout);
    m_aliveTimeout = aliveTimeout;
  }
  void 
  ArpCache::SetDeadTimeout (Time deadTimeout)
  {
    NS_LOG_FUNCTION (this << deadTimeout);
    m_deadTimeout = deadTimeout;
  }
  void 
  ArpCache::SetWaitReplyTimeout (Time waitReplyTimeout)
  {
    NS_LOG_FUNCTION (this << waitReplyTimeout);
    m_waitReplyTimeout = waitReplyTimeout;
  }
  
  Time
  ArpCache::GetAliveTimeout (void) const
  {
    NS_LOG_FUNCTION (this);
    return m_aliveTimeout;
  }
  Time
  ArpCache::GetDeadTimeout (void) const
  {
    NS_LOG_FUNCTION (this);
    return m_deadTimeout;
  }
  Time
  ArpCache::GetWaitReplyTimeout (void) const
  {
    NS_LOG_FUNCTION (this);
    return m_waitReplyTimeout;
  }
  
  void 
  ArpCache::SetArpRequestCallback (Callback<void, Ptr<const ArpCache>,
                                            Ipv4Address> arpRequestCallback)
  {
    NS_LOG_FUNCTION (this << &arpRequestCallback);
    m_arpRequestCallback = arpRequestCallback;
  }
  
  void 
  ArpCache::StartWaitReplyTimer (void)
  {
    NS_LOG_FUNCTION (this);
    if (!m_waitReplyTimer.IsRunning ())
      {
        NS_LOG_LOGIC ("Starting WaitReplyTimer at " << Simulator::Now () << " for " <<
                      m_waitReplyTimeout);
        m_waitReplyTimer = Simulator::Schedule (m_waitReplyTimeout, 
                                                &ArpCache::HandleWaitReplyTimeout, this);
      }
  }
  
  void
  ArpCache::HandleWaitReplyTimeout (void)
  {
    NS_LOG_FUNCTION (this);
    ArpCache::Entry* entry;
    bool restartWaitReplyTimer = false;
    for (CacheI i = m_arpCache.begin (); i != m_arpCache.end (); i++) 
      {
        entry = (*i).second;
        if (entry != 0 && entry->IsWaitReply ())
          {
            if (entry->GetRetries () < m_maxRetries)
              {
                NS_LOG_LOGIC ("node="<< m_device->GetNode ()->GetId () <<
                              ", ArpWaitTimeout for " << entry->GetIpv4Address () <<
                              " expired -- retransmitting arp request since retries = " <<
                              entry->GetRetries ());
                m_arpRequestCallback (this, entry->GetIpv4Address ());
                restartWaitReplyTimer = true;
                entry->IncrementRetries ();
              }
            else
              {
                NS_LOG_LOGIC ("node="<<m_device->GetNode ()->GetId () <<
                              ", wait reply for " << entry->GetIpv4Address () <<
                              " expired -- drop since max retries exceeded: " <<
                              entry->GetRetries ());
                entry->MarkDead ();
                entry->ClearRetries ();
                Ptr<Packet> pending = entry->DequeuePending ();
                while (pending != 0)
                  {
                    m_dropTrace (pending);
                    pending = entry->DequeuePending ();
                  }
              }
          }
  
      }
    if (restartWaitReplyTimer)
      {
        NS_LOG_LOGIC ("Restarting WaitReplyTimer at " << Simulator::Now ().GetSeconds ());
        m_waitReplyTimer = Simulator::Schedule (m_waitReplyTimeout, 
                                                &ArpCache::HandleWaitReplyTimeout, this);
      }
  }
  
  void 
  ArpCache::Flush (void)
  {
    NS_LOG_FUNCTION (this);
    for (CacheI i = m_arpCache.begin (); i != m_arpCache.end (); i++) 
      {
        delete (*i).second;
      }
    m_arpCache.erase (m_arpCache.begin (), m_arpCache.end ());
    if (m_waitReplyTimer.IsRunning ())
      {
        NS_LOG_LOGIC ("Stopping WaitReplyTimer at " << Simulator::Now ().GetSeconds () << " due to ArpCache flush");
        m_waitReplyTimer.Cancel ();
      }
  }
  
  void
  ArpCache::PrintArpCache (Ptr<OutputStreamWrapper> stream)
  {
    NS_LOG_FUNCTION (this << stream);
    std::ostream* os = stream->GetStream ();
  
    for (CacheI i = m_arpCache.begin (); i != m_arpCache.end (); i++)
      {
        *os << i->first << " dev ";
        std::string found = Names::FindName (m_device);
        if (Names::FindName (m_device) != "")
          {
            *os << found;
          }
        else
          {
            *os << static_cast<int> (m_device->GetIfIndex ());
          }
  
        *os << " lladdr " << i->second->GetMacAddress ();
  
        if (i->second->IsAlive ())
          {
            *os << " REACHABLE\n";
          }
        else if (i->second->IsWaitReply ())
          {
            *os << " DELAY\n";
          }
        else
          {
            *os << " STALE\n";
          }
      }
  }
  
  ArpCache::Entry *
  ArpCache::Lookup (Ipv4Address to)
  {
    NS_LOG_FUNCTION (this << 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_LOG_FUNCTION (this << to);
    NS_ASSERT (m_arpCache.find (to) == m_arpCache.end ());
  
    ArpCache::Entry *entry = new ArpCache::Entry (this);
    m_arpCache[to] = entry;
    entry->SetIpv4Address (to);
    return entry;
  }
  
  ArpCache::Entry::Entry (ArpCache *arp)
    : m_arp (arp),
      m_state (ALIVE),
      m_retries (0)
  {
    NS_LOG_FUNCTION (this << arp);
  }
  
  
  bool 
  ArpCache::Entry::IsDead (void)
  {
    NS_LOG_FUNCTION (this);
    return (m_state == DEAD) ? true : false;
  }
  bool 
  ArpCache::Entry::IsAlive (void)
  {
    NS_LOG_FUNCTION (this);
    return (m_state == ALIVE) ? true : false;
  }
  bool
  ArpCache::Entry::IsWaitReply (void)
  {
    NS_LOG_FUNCTION (this);
    return (m_state == WAIT_REPLY) ? true : false;
  }
  
  
  void 
  ArpCache::Entry::MarkDead (void) 
  {
    NS_LOG_FUNCTION (this);
    m_state = DEAD;
    ClearRetries ();
    UpdateSeen ();
  }
  void
  ArpCache::Entry::MarkAlive (Address macAddress) 
  {
    NS_LOG_FUNCTION (this << macAddress);
    NS_ASSERT (m_state == WAIT_REPLY);
    m_macAddress = macAddress;
    m_state = ALIVE;
    ClearRetries ();
    UpdateSeen ();
  }
  
  bool
  ArpCache::Entry::UpdateWaitReply (Ptr<Packet> waiting)
  {
    NS_LOG_FUNCTION (this << 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.
     */
    if (m_pending.size () >= m_arp->m_pendingQueueSize)
      {
        return false;
      }
    m_pending.push_back (waiting);
    return true;
  }
  void 
  ArpCache::Entry::MarkWaitReply (Ptr<Packet> waiting)
  {
    NS_LOG_FUNCTION (this << waiting);
    NS_ASSERT (m_state == ALIVE || m_state == DEAD);
    NS_ASSERT (m_pending.empty ());
    m_state = WAIT_REPLY;
    m_pending.push_back (waiting);
    UpdateSeen ();
    m_arp->StartWaitReplyTimer ();
  }
  
  Address
  ArpCache::Entry::GetMacAddress (void) const
  {
    NS_LOG_FUNCTION (this);
    return m_macAddress;
  }
  Ipv4Address 
  ArpCache::Entry::GetIpv4Address (void) const
  {
    NS_LOG_FUNCTION (this);
    return m_ipv4Address;
  }
  void 
  ArpCache::Entry::SetIpv4Address (Ipv4Address destination)
  {
    NS_LOG_FUNCTION (this << destination);
    m_ipv4Address = destination;
  }
  Time
  ArpCache::Entry::GetTimeout (void) const
  {
    NS_LOG_FUNCTION (this);
    switch (m_state) {
      case ArpCache::Entry::WAIT_REPLY:
        return m_arp->GetWaitReplyTimeout ();
      case ArpCache::Entry::DEAD:
        return m_arp->GetDeadTimeout ();
      case ArpCache::Entry::ALIVE:
        return m_arp->GetAliveTimeout ();
      default:
        NS_ASSERT (false);
        return Seconds (0);
        /* NOTREACHED */
      }
  }
  bool 
  ArpCache::Entry::IsExpired (void) const
  {
    NS_LOG_FUNCTION (this);
    Time timeout = GetTimeout ();
    Time delta = Simulator::Now () - m_lastSeen;
    NS_LOG_DEBUG ("delta=" << delta.GetSeconds () << "s");
    if (delta > timeout) 
      {
        return true;
      } 
    return false;
  }
  Ptr<Packet> 
  ArpCache::Entry::DequeuePending (void)
  {
    NS_LOG_FUNCTION (this);
    if (m_pending.empty ())
      {
        return 0;
      }
    else
      {
        Ptr<Packet> p = m_pending.front ();
        m_pending.pop_front ();
        return p;
      }
  }
  void 
  ArpCache::Entry::UpdateSeen (void)
  {
    NS_LOG_FUNCTION (this);
    m_lastSeen = Simulator::Now ();
  }
  uint32_t
  ArpCache::Entry::GetRetries (void) const
  {
    NS_LOG_FUNCTION (this);
    return m_retries;
  }
  void
  ArpCache::Entry::IncrementRetries (void)
  {
    NS_LOG_FUNCTION (this);
    m_retries++;
    UpdateSeen ();
  }
  void
  ArpCache::Entry::ClearRetries (void)
  {
    NS_LOG_FUNCTION (this);
    m_retries = 0;
  }
  
  } // namespace ns3
  
  