/* -*- 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

 *

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

 *          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"

namespace ns3 {

NS_LOG_COMPONENT_DEFINE ("ApWifiMac");

NS_OBJECT_ENSURE_REGISTERED (ApWifiMac);

TypeId

ApWifiMac::GetTypeId (void)

{

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

    .SetParent<RegularWifiMac> ()

    .SetGroupName ("Wifi")

    .AddConstructor<ApWifiMac> ()

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

                   TimeValue (MicroSeconds (102400)),

                   MakeTimeAccessor (&ApWifiMac::GetBeaconInterval,

                                     &ApWifiMac::SetBeaconInterval),

                   MakeTimeChecker ())

    .AddAttribute ("BeaconJitter", "A uniform random variable to cause the initial beacon starting time (after simulation time 0) "

                   "to be distributed between 0 and the BeaconInterval.",

                   StringValue ("ns3::UniformRandomVariable"),

                   MakePointerAccessor (&ApWifiMac::m_beaconJitter),

                   MakePointerChecker<UniformRandomVariable> ())

    .AddAttribute ("EnableBeaconJitter", "If beacons are enabled, whether to jitter the initial send event.",

                   BooleanValue (false),

                   MakeBooleanAccessor (&ApWifiMac::m_enableBeaconJitter),

                   MakeBooleanChecker ())

    .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);

  m_beaconDca->SetTxMiddle (m_txMiddle);

  //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)

{

  NS_LOG_FUNCTION (this << 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

{

  NS_LOG_FUNCTION (this);

  return m_enableBeaconGeneration;

}

Time

ApWifiMac::GetBeaconInterval (void) const

{

  NS_LOG_FUNCTION (this);

  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 << &linkUp);

  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 (802.11 time unit), see IEEE Std. 802.11-2012");

    }

  m_beaconInterval = interval;

}

void

ApWifiMac::StartBeaconing (void)

{

  NS_LOG_FUNCTION (this);

  SendOneBeacon ();

}

int64_t

ApWifiMac::AssignStreams (int64_t stream)

{

  NS_LOG_FUNCTION (this << stream);

  m_beaconJitter->SetStream (stream);

  return 1;

}

void

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

                        Mac48Address to)

{

  NS_LOG_FUNCTION (this << packet << from << 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 << static_cast<uint32_t> (tid));

  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 ();

    }

  if (m_htSupported || m_vhtSupported)

    {

      hdr.SetNoOrder ();

    }

  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)

{

  NS_LOG_FUNCTION (this << packet << 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

{

  NS_LOG_FUNCTION (this);

  return true;

}

SupportedRates

ApWifiMac::GetSupportedRates (void) const

{

  NS_LOG_FUNCTION (this);

  SupportedRates rates;

  //If it is an HT-AP then add the BSSMembershipSelectorSet

  //which only includes 127 for HT now. The standard says that the BSSMembershipSelectorSet

  //must have its MSB set to 1 (must be treated as a Basic Rate)

  //Also the standard mentioned that at leat 1 element should be included in the SupportedRates the rest can be in the ExtendedSupportedRates

  if (m_htSupported || m_vhtSupported)

    {

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

        {

          rates.SetBasicRate (m_phy->GetBssMembershipSelector (i));

        }

    }

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

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

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

    {

      WifiMode mode = m_phy->GetMode (i);

      uint32_t channelWidth = m_phy->GetChannelWidth ();

        {

          channelWidth = 20;

        }

      rates.AddSupportedRate (mode.GetDataRate (channelWidth, false, 1));

      //Add rates that are part of the BSSBasicRateSet (manufacturer dependent!)

      //here we choose to add the mandatory rates to the BSSBasicRateSet,

      //exept for 802.11b where we assume that only the non HR-DSSS rates are part of the BSSBasicRateSet

      if (mode.IsMandatory () && (mode.GetModulationClass () != WIFI_MOD_CLASS_HR_DSSS))

        {

          m_stationManager->AddBasicMode (mode);

        }

    }

  //set the basic rates

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

    {

      WifiMode mode = m_stationManager->GetBasicMode (j);

      uint32_t channelWidth = m_phy->GetChannelWidth ();

        {

          channelWidth = 20;

        }

      rates.SetBasicRate (mode.GetDataRate (channelWidth, false, 1));

    }

  return rates;

}

HtCapabilities

ApWifiMac::GetHtCapabilities (void) const

{

  HtCapabilities capabilities;

  capabilities.SetHtSupported (1);

  if (m_htSupported)

    {

      capabilities.SetLdpc (m_phy->GetLdpc ());

      capabilities.SetSupportedChannelWidth (m_phy->GetChannelWidth () == 40);

      capabilities.SetShortGuardInterval20 (m_phy->GetGuardInterval ());

      capabilities.SetShortGuardInterval40 (m_phy->GetChannelWidth () == 40 && m_phy->GetGuardInterval ());

      capabilities.SetGreenfield (m_phy->GetGreenfield ());

      capabilities.SetMaxAmsduLength (1); //hardcoded for now (TBD)

      capabilities.SetLSigProtectionSupport (!m_phy->GetGreenfield ());

      capabilities.SetMaxAmpduLength (3); //hardcoded for now (TBD)

      uint64_t maxSupportedRate = 0; //in bit/s

      for (uint8_t i = 0; i < m_phy->GetNMcs (); i++)

        {

          WifiMode mcs = m_phy->GetMcs (i);

          capabilities.SetRxMcsBitmask (mcs.GetMcsValue ());

          if (mcs.GetDataRate (m_phy->GetGuardInterval (), m_phy->GetGuardInterval (), 1) > maxSupportedRate)

            {

              maxSupportedRate = mcs.GetDataRate (m_phy->GetGuardInterval (), m_phy->GetGuardInterval (), 1);

            }

        }

      capabilities.SetRxHighestSupportedDataRate (maxSupportedRate / 1e6); //in Mbit/s

      capabilities.SetTxMcsSetDefined (m_phy->GetNMcs () > 0);

      capabilities.SetTxMaxNSpatialStreams (m_phy->GetNumberOfTransmitAntennas ());

    }

  return capabilities;

}

VhtCapabilities

ApWifiMac::GetVhtCapabilities (void) const

{

  VhtCapabilities capabilities;

  capabilities.SetVhtSupported (1);

  if (m_vhtSupported)

    {

      if (m_phy->GetChannelWidth () == 160)

        {

          capabilities.SetSupportedChannelWidthSet (1);

        }

      else

        {

          capabilities.SetSupportedChannelWidthSet (0);

        }

      capabilities.SetMaxMpduLength (2); //hardcoded for now (TBD)

      capabilities.SetRxLdpc (m_phy->GetLdpc ());

      capabilities.SetShortGuardIntervalFor80Mhz ((m_phy->GetChannelWidth () == 80) && m_phy->GetGuardInterval ());

      capabilities.SetShortGuardIntervalFor160Mhz ((m_phy->GetChannelWidth () == 160) && m_phy->GetGuardInterval ());

      capabilities.SetMaxAmpduLengthExponent (7); //hardcoded for now (TBD)

      uint8_t maxMcs = 0;

      for (uint8_t i = 0; i < m_phy->GetNMcs (); i++)

        {

          WifiMode mcs = m_phy->GetMcs (i);

          if (mcs.GetMcsValue () > maxMcs)

            {

              maxMcs = mcs.GetMcsValue ();

            }

        }

      capabilities.SetRxMcsMap (maxMcs, 1); //Only 1 SS is currently supported

      capabilities.SetTxMcsMap (maxMcs, 1); //Only 1 SS is currently supported

    }

  return capabilities;

}

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 ());

  if (m_htSupported || m_vhtSupported)

    {

      probe.SetHtCapabilities (GetHtCapabilities ());

      hdr.SetNoOrder ();

    }

  if (m_vhtSupported)

    {

      probe.SetVhtCapabilities (GetVhtCapabilities ());

    }

  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);

  if (m_htSupported || m_vhtSupported)

    {

      assoc.SetHtCapabilities (GetHtCapabilities ());

      hdr.SetNoOrder ();

    }

  if (m_vhtSupported)

    {

      assoc.SetVhtCapabilities (GetVhtCapabilities ());

    }

  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);