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

/*

 * Copyright (c) 2006, 2009 INRIA

 * Copyright (c) 2009 MIRKO BANCHI

 *

 * 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>

 * Author: Mirko Banchi <mk.banchi@gmail.com>

 */

#include "ap-wifi-mac.h"

#include "ns3/assert.h"

#include "ns3/log.h"

#include "ns3/simulator.h"

#include "ns3/string.h"

#include "ns3/pointer.h"

#include "ns3/boolean.h"

#include "qos-tag.h"

#include "wifi-phy.h"

#include "dcf-manager.h"

#include "mac-rx-middle.h"

#include "mac-tx-middle.h"

#include "mgt-headers.h"

#include "mac-low.h"

#include "amsdu-subframe-header.h"

#include "msdu-aggregator.h"

NS_LOG_COMPONENT_DEFINE ("ApWifiMac");

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (ApWifiMac);

TypeId

ApWifiMac::GetTypeId (void)

{

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

    .SetParent<RegularWifiMac> ()

    .AddConstructor<ApWifiMac> ()

    .AddAttribute ("BeaconInterval", "Delay between two beacons",

                   TimeValue (MicroSeconds (102400)),

                   MakeTimeAccessor (&ApWifiMac::GetBeaconInterval,

                                     &ApWifiMac::SetBeaconInterval),

                   MakeTimeChecker ())

    .AddAttribute ("BeaconGeneration", "Whether or not beacons are generated.",

                   BooleanValue (true),

                   MakeBooleanAccessor (&ApWifiMac::SetBeaconGeneration,

                                        &ApWifiMac::GetBeaconGeneration),

                   MakeBooleanChecker ())

  ;

  return tid;

}

ApWifiMac::ApWifiMac ()

{

  NS_LOG_FUNCTION (this);

  m_beaconDca = CreateObject<DcaTxop> ();

  m_beaconDca->SetAifsn (1);

  m_beaconDca->SetMinCw (0);

  m_beaconDca->SetMaxCw (0);

  m_beaconDca->SetLow (m_low);

  m_beaconDca->SetManager (m_dcfManager);

  // Let the lower layers know that we are acting as an AP.

  SetTypeOfStation (AP);

  m_enableBeaconGeneration = false;

}

ApWifiMac::~ApWifiMac ()

{

  NS_LOG_FUNCTION (this);

}

void

ApWifiMac::DoDispose ()

{

  NS_LOG_FUNCTION (this);

  m_beaconDca = 0;

  m_enableBeaconGeneration = false;

  m_beaconEvent.Cancel ();

  RegularWifiMac::DoDispose ();

}

void

ApWifiMac::SetAddress (Mac48Address address)

{

  // As an AP, our MAC address is also the BSSID. Hence we are

  // overriding this function and setting both in our parent class.

  RegularWifiMac::SetAddress (address);

  RegularWifiMac::SetBssid (address);

}

void

ApWifiMac::SetBeaconGeneration (bool enable)

{

  NS_LOG_FUNCTION (this << enable);

  if (!enable)

    {

      m_beaconEvent.Cancel ();

    }

  else if (enable && !m_enableBeaconGeneration)

    {

      m_beaconEvent = Simulator::ScheduleNow (&ApWifiMac::SendOneBeacon, this);

    }

  m_enableBeaconGeneration = enable;

}

bool

ApWifiMac::GetBeaconGeneration (void) const

{

  return m_enableBeaconGeneration;

}

Time

ApWifiMac::GetBeaconInterval (void) const

{

  return m_beaconInterval;

}

void

ApWifiMac::SetWifiRemoteStationManager (Ptr<WifiRemoteStationManager> stationManager)

{

  NS_LOG_FUNCTION (this << stationManager);

  m_beaconDca->SetWifiRemoteStationManager (stationManager);

  RegularWifiMac::SetWifiRemoteStationManager (stationManager);

}

void

ApWifiMac::SetLinkUpCallback (Callback<void> linkUp)

{

  NS_LOG_FUNCTION (this);

  RegularWifiMac::SetLinkUpCallback (linkUp);

  // The approach taken here is that, from the point of view of an AP,

  // the link is always up, so we immediately invoke the callback if

  // one is set

  linkUp ();

}

void

ApWifiMac::SetBeaconInterval (Time interval)

{

  NS_LOG_FUNCTION (this << interval);

  if ((interval.GetMicroSeconds () % 1024) != 0)

    {

      NS_LOG_WARN ("beacon interval should be multiple of 1024us, see IEEE Std. 802.11-2007, section 11.1.1.1");

    }

  m_beaconInterval = interval;

}

void

ApWifiMac::StartBeaconing (void)

{

  NS_LOG_FUNCTION (this);

  SendOneBeacon ();

}

void

ApWifiMac::ForwardDown (Ptr<const Packet> packet, Mac48Address from,

                        Mac48Address to)

{

  // If we are not a QoS AP then we definitely want to use AC_BE to

  // transmit the packet. A TID of zero will map to AC_BE (through \c

  // QosUtilsMapTidToAc()), so we use that as our default here.

  uint8_t tid = 0;

  // If we are a QoS AP then we attempt to get a TID for this packet

  if (m_qosSupported)

    {

      tid = QosUtilsGetTidForPacket (packet);

      // Any value greater than 7 is invalid and likely indicates that

      // the packet had no QoS tag, so we revert to zero, which'll

      // mean that AC_BE is used.

      if (tid >= 7)

        {

          tid = 0;

        }

    }

  ForwardDown (packet, from, to, tid);

}

void

ApWifiMac::ForwardDown (Ptr<const Packet> packet, Mac48Address from,

                        Mac48Address to, uint8_t tid)

{

  NS_LOG_FUNCTION (this << packet << from << to);

  WifiMacHeader hdr;

  // For now, an AP that supports QoS does not support non-QoS

  // associations, and vice versa. In future the AP model should

  // support simultaneously associated QoS and non-QoS STAs, at which

  // point there will need to be per-association QoS state maintained

  // by the association state machine, and consulted here.

  if (m_qosSupported)

    {

      hdr.SetType (WIFI_MAC_QOSDATA);

      hdr.SetQosAckPolicy (WifiMacHeader::NORMAL_ACK);

      hdr.SetQosNoEosp ();

      hdr.SetQosNoAmsdu ();

      // Transmission of multiple frames in the same TXOP is not

      // supported for now

      hdr.SetQosTxopLimit (0);

      // Fill in the QoS control field in the MAC header

      hdr.SetQosTid (tid);

    }

  else

    {

      hdr.SetTypeData ();

    }

  hdr.SetAddr1 (to);

  hdr.SetAddr2 (GetAddress ());

  hdr.SetAddr3 (from);

  hdr.SetDsFrom ();

  hdr.SetDsNotTo ();

  if (m_qosSupported)

    {

      // Sanity check that the TID is valid

      NS_ASSERT (tid < 8);

      m_edca[QosUtilsMapTidToAc (tid)]->Queue (packet, hdr);

    }

  else

    {

      m_dca->Queue (packet, hdr);

    }

}

void

ApWifiMac::Enqueue (Ptr<const Packet> packet, Mac48Address to, Mac48Address from)

{

  NS_LOG_FUNCTION (this << packet << to << from);

  if (to.IsBroadcast () || m_stationManager->IsAssociated (to))

    {

      ForwardDown (packet, from, to);

    }

}

void

ApWifiMac::Enqueue (Ptr<const Packet> packet, Mac48Address to)

{

  // We're sending this packet with a from address that is our own. We

  // get that address from the lower MAC and make use of the

  // from-spoofing Enqueue() method to avoid duplicated code.

  Enqueue (packet, to, m_low->GetAddress ());

}

bool

ApWifiMac::SupportsSendFrom (void) const

{

  return true;

}

SupportedRates

ApWifiMac::GetSupportedRates (void) const

{

  // send the set of supported rates and make sure that we indicate

  // the Basic Rate set in this set of supported rates.

  SupportedRates rates;

  for (uint32_t i = 0; i < m_phy->GetNModes (); i++)

    {

      WifiMode mode = m_phy->GetMode (i);

      rates.AddSupportedRate (mode.GetDataRate ());

    }

  // set the basic rates

  for (uint32_t j = 0; j < m_stationManager->GetNBasicModes (); j++)

    {

      WifiMode mode = m_stationManager->GetBasicMode (j);

      rates.SetBasicRate (mode.GetDataRate ());

    }

  return rates;

}

void

ApWifiMac::SendProbeResp (Mac48Address to)

{

  NS_LOG_FUNCTION (this << to);

  WifiMacHeader hdr;

  hdr.SetProbeResp ();

  hdr.SetAddr1 (to);

  hdr.SetAddr2 (GetAddress ());

  hdr.SetAddr3 (GetAddress ());

  hdr.SetDsNotFrom ();

  hdr.SetDsNotTo ();

  Ptr<Packet> packet = Create<Packet> ();

  MgtProbeResponseHeader probe;

  probe.SetSsid (GetSsid ());

  probe.SetSupportedRates (GetSupportedRates ());

  probe.SetBeaconIntervalUs (m_beaconInterval.GetMicroSeconds ());

  packet->AddHeader (probe);

  // The standard is not clear on the correct queue for management

  // frames if we are a QoS AP. The approach taken here is to always

  // use the DCF for these regardless of whether we have a QoS

  // association or not.

  m_dca->Queue (packet, hdr);

}

void

ApWifiMac::SendAssocResp (Mac48Address to, bool success)

{

  NS_LOG_FUNCTION (this << to << success);

  WifiMacHeader hdr;

  hdr.SetAssocResp ();

  hdr.SetAddr1 (to);

  hdr.SetAddr2 (GetAddress ());

  hdr.SetAddr3 (GetAddress ());

  hdr.SetDsNotFrom ();

  hdr.SetDsNotTo ();

  Ptr<Packet> packet = Create<Packet> ();

  MgtAssocResponseHeader assoc;

  StatusCode code;

  if (success)

    {

      code.SetSuccess ();

    }

  else

    {

      code.SetFailure ();

    }

  assoc.SetSupportedRates (GetSupportedRates ());

  assoc.SetStatusCode (code);

  packet->AddHeader (assoc);

  // The standard is not clear on the correct queue for management

  // frames if we are a QoS AP. The approach taken here is to always

  // use the DCF for these regardless of whether we have a QoS

  // association or not.

  m_dca->Queue (packet, hdr);

}

void

ApWifiMac::SendOneBeacon (void)

{

  NS_LOG_FUNCTION (this);

  WifiMacHeader hdr;

  hdr.SetBeacon ();

  hdr.SetAddr1 (Mac48Address::GetBroadcast ());

  hdr.SetAddr2 (GetAddress ());

  hdr.SetAddr3 (GetAddress ());

  hdr.SetDsNotFrom ();

  hdr.SetDsNotTo ();

  Ptr<Packet> packet = Create<Packet> ();

  MgtBeaconHeader beacon;

  beacon.SetSsid (GetSsid ());

  beacon.SetSupportedRates (GetSupportedRates ());

  beacon.SetBeaconIntervalUs (m_beaconInterval.GetMicroSeconds ());

  packet->AddHeader (beacon);

  // The beacon has it's own special queue, so we load it in there

  m_beaconDca->Queue (packet, hdr);

  m_beaconEvent = Simulator::Schedule (m_beaconInterval, &ApWifiMac::SendOneBeacon, this);

}

void

ApWifiMac::TxOk (const WifiMacHeader &hdr)

{

  NS_LOG_FUNCTION (this);

  RegularWifiMac::TxOk (hdr);

  if (hdr.IsAssocResp ()

      && m_stationManager->IsWaitAssocTxOk (hdr.GetAddr1 ()))

    {

      NS_LOG_DEBUG ("associated with sta=" << hdr.GetAddr1 ());

      m_stationManager->RecordGotAssocTxOk (hdr.GetAddr1 ());

    }

}

void

ApWifiMac::TxFailed (const WifiMacHeader &hdr)

{

  NS_LOG_FUNCTION (this);

  RegularWifiMac::TxFailed (hdr);

  if (hdr.IsAssocResp ()

      && m_stationManager->IsWaitAssocTxOk (hdr.GetAddr1 ()))

    {

      NS_LOG_DEBUG ("assoc failed with sta=" << hdr.GetAddr1 ());

      m_stationManager->RecordGotAssocTxFailed (hdr.GetAddr1 ());

    }

}

void

ApWifiMac::Receive (Ptr<Packet> packet, const WifiMacHeader *hdr)

{

  NS_LOG_FUNCTION (this << packet << hdr);

  Mac48Address from = hdr->GetAddr2 ();

  if (hdr->IsData ())

    {

      Mac48Address bssid = hdr->GetAddr1 ();

      if (!hdr->IsFromDs ()

          && hdr->IsToDs ()

          && bssid == GetAddress ()

          && m_stationManager->IsAssociated (from))

        {

          Mac48Address to = hdr->GetAddr3 ();

          if (to == GetAddress ())

            {

              NS_LOG_DEBUG ("frame for me from=" << from);

              if (hdr->IsQosData ())

                {

                  if (hdr->IsQosAmsdu ())

                    {

                      NS_LOG_DEBUG ("Received A-MSDU from=" << from << ", size=" << packet->GetSize ());

                      DeaggregateAmsduAndForward (packet, hdr);

                      packet = 0;

                    }

                  else

                    {

                      ForwardUp (packet, from, bssid);

                    }

                }

              else

                {

                  ForwardUp (packet, from, bssid);

                }

            }

          else if (to.IsGroup ()

                   || m_stationManager->IsAssociated (to))

            {

              NS_LOG_DEBUG ("forwarding frame from=" << from << ", to=" << to);

              Ptr<Packet> copy = packet->Copy ();

              // If the frame we are forwarding is of type QoS Data,

              // then we need to preserve the UP in the QoS control

              // header...

              if (hdr->IsQosData ())

                {

                  ForwardDown (packet, from, to, hdr->GetQosTid ());

                }

              else

                {

                  ForwardDown (packet, from, to);

                }

              ForwardUp (copy, from, to);

            }

          else

            {

              ForwardUp (packet, from, to);

            }

        }

      else if (hdr->IsFromDs ()

               && hdr->IsToDs ())

        {

          // this is an AP-to-AP frame

          // we ignore for now.

          NotifyRxDrop (packet);

        }

      else

        {

          // we can ignore these frames since

          // they are not targeted at the AP

          NotifyRxDrop (packet);

        }

      return;

    }

  else if (hdr->IsMgt ())

    {

      if (hdr->IsProbeReq ())

        {

          NS_ASSERT (hdr->GetAddr1 ().IsBroadcast ());

          SendProbeResp (from);

          return;

        }

      else if (hdr->GetAddr1 () == GetAddress ())

        {

          if (hdr->IsAssocReq ())

            {

              // first, verify that the the station's supported

              // rate set is compatible with our Basic Rate set

              MgtAssocRequestHeader assocReq;

              packet->RemoveHeader (assocReq);

              SupportedRates rates = assocReq.GetSupportedRates ();

              bool problem = false;

              for (uint32_t i = 0; i < m_stationManager->GetNBasicModes (); i++)

                {

                  WifiMode mode = m_stationManager->GetBasicMode (i);

                  if (!rates.IsSupportedRate (mode.GetDataRate ()))

                    {

                      problem = true;

                      break;

                    }

                }

              if (problem)

                {