Attachment #1008 for bug #1021

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{
  //PM STATE Machine
  //Check that a given beacon is not from our interface
  Simulator::Schedule (beaconInterval - TuToTime (m_maxBeaconShift + 1), &PeerManagementProtocol::DoShiftBeacon, this, interface);
  for (PeerManagementProtocolMacMap::const_iterator i = m_plugins.begin (); i != m_plugins.end (); i++)
    {
      if (i->second->GetAddress () == peerAddress)

          peerLink = InitiateLink (interface, peerAddress, Mac48Address::GetBroadcast ());
          peerLink->MLMEActivePeerLinkOpen ();
        }
      else
        {
          //PMP has cancelled new link and should not open it.
    	    return;
        }
    }
  peerLink->SetBeaconInformation (Simulator::Now (), beaconInterval);
  if (GetBeaconCollisionAvoidance ())

  UniformVariable beaconShift (-m_maxBeaconShift, m_maxBeaconShift);
  PeerLinksMap::iterator iface = m_peerLinks.find (interface);
  NS_ASSERT (iface != m_peerLinks.end ());
  PeerManagementProtocolMacMap::const_iterator plugin = m_plugins.find (interface);
  NS_ASSERT (plugin != m_plugins.end ());
  std::map<uint32_t, Time>::const_iterator lastBeacon = m_lastBeacon.find (interface);
  std::map<uint32_t, Time>::const_iterator beaconInterval = m_beaconInterval.find (interface);
  if ((lastBeacon == m_lastBeacon.end ()) || (beaconInterval == m_beaconInterval.end ()))
    {
      return;
    }
  //my last beacon in 256 us units
  uint16_t lastBeaconInTimeElement = (uint16_t) ((lastBeacon->second.GetMicroSeconds () >> 8) & 0xffff);
  if (TuToTime (m_maxBeaconShift) > m_beaconInterval[interface])
    {
      NS_FATAL_ERROR ("Wrong beacon shift parameters");
      return;
    }
  //check whether we need to shift our beacon
  bool shiftIsNeeded = false;

  if (iface->second.size () == 0)
    {
      //I have no peers - may be our beacons are in collision
      shiftIsNeeded = true;
    }
  //check whether all my peers receive my beacon and I'am not in collision with other beacons
  for (PeerLinksOnInterface::iterator i = iface->second.begin (); i != iface->second.end (); i++)
    {
      bool isMyBeaconRec = false;
      bool isCollision = false;
      IeBeaconTiming::NeighboursTimingUnitsList neighbours;
      neighbours = (*i)->GetBeaconTimingElement ().GetNeighboursTimingElementsList ();
      for (IeBeaconTiming::NeighboursTimingUnitsList::const_iterator j = neighbours.begin (); j != neighbours.end (); j++)
      for (IeBeaconTiming::NeighboursTimingUnitsList::const_iterator j = neighbours.begin (); j
          != neighbours.end (); j++)
        {
          if ((*i)->GetPeerAid () == (*j)->GetAid ())
            {
              // I am presented at neighbour's list of neighbors
              isMyBeaconRec = true;
              continue;
            }
          if (
              ((int16_t) ((*j)->GetLastBeacon () - lastBeaconInTimeElement) >= 0)
              && 
              (((*j)->GetLastBeacon () - lastBeaconInTimeElement) % (4 * TimeToTu (beaconInterval->second))== 0)
              )
            {
               isCollision=true;
            }
          //Timing element keeps beacon receiving times in 256us units, TU=1024us
          if ((int) ((int)(*j)->GetLastBeacon () / 4 - (int)TimeToTu (lastBeacon->second)) % TimeToTu (
              beaconInterval->second)
              != 0)
            {
              continue;
            }
              int shift = 0;
              do
                {
                  shift = (int) beaconShift.GetValue ();
                }
              while (shift == 0);
              PeerManagementProtocolMacMap::iterator plugin = m_plugins.find (interface);
              NS_ASSERT (plugin != m_plugins.end ());
              plugin->second->SetBeaconShift (TuToTime (shift));
              return;
        }
      // If I am not present in neighbor's beacon timing element, this may be caused vy collisions with
      // other beacons, and no peering link was established.
      if ((!isMyBeaconRec)||(isCollision))
        {
          shiftIsNeeded=true;
          break;
        }
     }
  // Now, shift beacon. The value is chosen randomly:
  if (!shiftIsNeeded)
    {
      return;
    }
  int shift = 0;
  do
    {
      shift = (int) beaconShift.GetValue ();
    }
  while (shift == 0);
  // Apply beacon shift parameters:
  PeerManagementProtocolMacMap::iterator plugin = m_plugins.find (interface);
  NS_ASSERT (plugin != m_plugins.end ());
  plugin->second->SetBeaconShift (TuToTime (shift));
  return;
}

Time
PeerManagementProtocol::TuToTime (int x)
{
  return MicroSeconds (x * 1024);
}

int
PeerManagementProtocol::TimeToTu (Time x)
{
  return (uint32_t) (x.GetMicroSeconds () / 1024);

PeerManagementProtocol::NotifyBeaconSent (uint32_t interface, Time beaconInterval)
{
  m_lastBeacon[interface] = Simulator::Now ();
  Simulator::Schedule(beaconInterval - TuToTime(m_maxBeaconShift + 1), &PeerManagementProtocol::DoShiftBeacon,this, interface);
  m_beaconInterval[interface] = beaconInterval;
}
PeerManagementProtocol::Statistics::Statistics (uint16_t t) :

(-)a/src/devices/mesh/dot11s/peer-management-protocol.h (-2 / +2 lines)

Lines 198-205	Link Here

198

   * \name Time<-->TU converters:

198

   * \name Time<-->TU converters:

199

   * \{

199

   * \{

200

*/

200

*/

201

  Time TuToTime (uint32_t x);

201

  Time TuToTime (int x);

202

  uint32_t TimeToTu (Time x);

202

  int TimeToTu (Time x);

203

  ///\}

203

  ///\}

204

205

  /// Aux. method to register open links

205

  /// Aux. method to register open links

(-)a/src/devices/mesh/mesh-wifi-interface-mac.cc (-1 lines)

Lines 563-569	Link Here

563

  NS_LOG_DEBUG (GetAddress () << " is sending beacon");

563

  NS_LOG_DEBUG (GetAddress () << " is sending beacon");

564

565

  NS_ASSERT (!m_beaconSendEvent.IsRunning ());

565

  NS_ASSERT (!m_beaconSendEvent.IsRunning ());

566

  NS_ASSERT (Simulator::Now ().GetMicroSeconds () == GetTbtt ().GetMicroSeconds ()); // assert that beacon is just on time

567

566

568

  // Form & send beacon

567

  // Form & send beacon

569

  MeshWifiBeacon beacon (GetSsid (), GetSupportedRates (), m_beaconInterval.GetMicroSeconds ());

568

  MeshWifiBeacon beacon (GetSsid (), GetSupportedRates (), m_beaconInterval.GetMicroSeconds ());

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