Attachment #2652 for bug #2483

View | Details | Raw Unified | Return to bug 2483
Collapse All | Expand All




  // 
  // If we're connected to a real world network, then some of the fields sizes 
  // in an ARP packet can vary in ways not seen in simulations.  We need to be
  // able to detect ARP packets with headers we don't recognize and not process
  // them instead of crashing.  The ArpHeader will return 0 if it can't deal
  // with the received header.
  //

      NS_LOG_LOGIC (cache->GetInterface ()->GetAddress (i).GetLocal () << ", ");
    }

  /**
   * \internal
   * Note: we do not update the ARP cache when we receive an ARP request
   *  from an unknown node. See \bugid{107}
   */
  bool found = false;
  for (uint32_t i = 0; i < cache->GetInterface ()->GetNAddresses (); i++)
    {
      if (arp.IsRequest () && arp.GetDestinationIpv4Address () == 
          cache->GetInterface ()->GetAddress (i).GetLocal ())
        {
          ArpCache::Entry *entry = cache->Lookup (arp.GetSourceIpv4Address ());
          if (entry!=0)
          {
            if (entry->IsWaitReply ())
            {
              NS_LOG_LOGIC ("node="<<m_node->GetId ()<<", got request from " <<
                            arp.GetSourceIpv4Address () <<
                            " for waiting entry -- flush and later send reply");
              entry->MarkAlive (arp.GetSourceHardwareAddress ());
            }
            else
            {
              // Ignore-- already have an entry
              NS_LOG_LOGIC("node="<<m_node->GetId () << ", got request from " <<
                           arp.GetSourceIpv4Address () << " for non-waiting entry");
              entry->UpdateSeen ();
            }
          }
          else
          {
            // No entry for this source, but add one now (RFC 826)
            NS_LOG_LOGIC("node="<<m_node->GetId ()<<", got request from " <<
                         arp.GetSourceIpv4Address () <<
                         " for non-existent entry-- adding ");
            ArpCache::Entry *entry = cache->Add (arp.GetSourceIpv4Address ());
            entry->MarkAlive (arp.GetSourceHardwareAddress ());
          }

          found = true;
          NS_LOG_LOGIC ("node="<<m_node->GetId () <<", got request from " <<
                        arp.GetSourceIpv4Address () << " -- send reply");
          SendArpReply (cache, arp.GetDestinationIpv4Address (), arp.GetSourceIpv4Address (),
                        arp.GetSourceHardwareAddress ());
          break;
        }
      else if (arp.IsReply () &&
               arp.GetDestinationIpv4Address ().IsEqual (cache->GetInterface ()->GetAddress (i).GetLocal ()) &&
               arp.GetDestinationHardwareAddress () == device->GetAddress ())
        {

              if (entry->IsWaitReply ()) 
                {
                  NS_LOG_LOGIC ("node="<< m_node->GetId () << 
                                ", got reply from " << arp.GetSourceIpv4Address () <<
                                " for waiting entry -- flush");
                  Address from_mac = arp.GetSourceHardwareAddress ();
                  entry->MarkAlive (from_mac);
                  ArpCache::Ipv4PayloadHeaderPair pending = entry->DequeuePending ();

              else 
                {
                  // ignore this reply which might well be an attempt 
                  // at poisoning my arp cache.
                  NS_LOG_LOGIC ("node=" << m_node->GetId () << ", got reply from " <<
                                arp.GetSourceIpv4Address () <<
                                " for non-waiting entry -- drop");
                  m_dropTrace (packet);

            } 
          else 
            {
              NS_LOG_LOGIC ("node=" << m_node->GetId () << ", got reply for unknown entry -- drop");
              m_dropTrace (packet);
            }
          break;

    }
  if (found == false)
    {
      NS_LOG_LOGIC ("node=" << m_node->GetId () << ", got request from " <<
                    arp.GetSourceIpv4Address () << " for unknown address " <<
                    arp.GetDestinationIpv4Address () << " -- drop");
    }

Return to bug 2483