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

/*

 * Copyright (c) 2005,2006,2007 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 "mac-stations.h"

#include "ns3/assert.h"

#include "ns3/log.h"

NS_LOG_COMPONENT_DEFINE ("MacStations");

namespace ns3 {

/**

 * _all_ broadcast and multicast frames are transmitted

 * at the same constant default rate because since we don't

 * have any kind of feedback from their transmission,

 * we cannot adjust the rate, so, we pick one which ensures

 * that all frames reach destination.

 */

class NonUnicastMacStation : public MacStation

{

public:

  NonUnicastMacStation (MacStations *stations);

  virtual void ReportRxOk (double rxSnr, WifiMode txMode);

  virtual void ReportRtsFailed (void);

  virtual void ReportDataFailed (void);

  virtual void ReportRtsOk (double ctsSnr, WifiMode ctsMode, double rtsSnr);

  virtual void ReportDataOk (double ackSnr, WifiMode ackMode, double dataSnr);

  virtual WifiMode GetDataMode (uint32_t size);

  virtual WifiMode GetRtsMode (void);

private:

  virtual MacStations *GetStations (void) const;

  MacStations *m_stations;

};

NonUnicastMacStation::NonUnicastMacStation (MacStations *stations)

  : m_stations (stations)

{}

void 

NonUnicastMacStation::ReportRxOk (double rxSnr, WifiMode txMode)

{

  NS_ASSERT (false);

}

void 

NonUnicastMacStation::ReportRtsFailed (void)

{

  NS_ASSERT (false);

}

void 

NonUnicastMacStation::ReportDataFailed (void)

{

  NS_ASSERT (false);

}

void 

NonUnicastMacStation::ReportRtsOk (double ctsSnr, WifiMode ctsMode, double rtsSnr)

{

  NS_ASSERT (false);

}

void 

NonUnicastMacStation::ReportDataOk (double ackSnr, WifiMode ackMode, double dataSnr)

{

  NS_ASSERT (false);

}

WifiMode 

NonUnicastMacStation::GetDataMode (uint32_t size)

{

  WifiMode mode = m_stations->GetBasicMode (0);

  NS_LOG_DEBUG ("non-unicast size="<<size<<", mode="<<mode);

  return mode;

}

WifiMode 

NonUnicastMacStation::GetRtsMode (void)

{

  NS_ASSERT (false);

  // theoretically, no rts for broadcast/multicast packets.

  return m_stations->GetBasicMode (0);

}

MacStations *

NonUnicastMacStation::GetStations (void) const

{

  return m_stations;

}

} // namespace ns3

namespace ns3 {

MacStations::MacStations (WifiMode defaultTxMode)

  : m_defaultTxMode (defaultTxMode),

    m_nonUnicast (new NonUnicastMacStation (this))

{

  m_basicModes.push_back (m_defaultTxMode);

  NS_ASSERT (m_defaultTxMode.IsMandatory ());

}

MacStations::~MacStations ()

{

  for (Stations::const_iterator i = m_stations.begin (); i != m_stations.end (); i++) 

    {

      delete (*i).second;

    }

  m_stations.clear ();

  delete m_nonUnicast;

}

MacStation *

MacStations::Lookup (Mac48Address address)

{

  if (address.IsBroadcast () ||

      address.IsMulticast ())

    {

      return m_nonUnicast;

    }

  for (Stations::const_iterator i = m_stations.begin (); i != m_stations.end (); i++) 

    {

      if ((*i).first == address)

        {

          return (*i).second;

        }

    }

  MacStation *station = CreateStation ();

  m_stations.push_back (std::make_pair (address, station));

  return station;

}

MacStation *

MacStations::LookupNonUnicast (void)

{

  return m_nonUnicast;

}

WifiMode 

MacStations::GetDefaultMode (void) const

{

  return m_defaultTxMode;

}

uint32_t 

MacStations::GetNBasicModes (void) const

{

  return m_basicModes.size ();

}

WifiMode 

MacStations::GetBasicMode (uint32_t i) const

{

  NS_ASSERT (i < m_basicModes.size ());

}

MacStations::BasicModesIterator 

MacStations::BeginBasicModes (void) const

{

  return m_basicModes.begin ();

}

MacStations::BasicModesIterator 

MacStations::EndBasicModes (void) const

{

  return m_basicModes.end ();

}

} // namespace ns3

/***************************************************************

 *           MacStation below.

 ***************************************************************/ 

namespace ns3 {

MacStation::MacStation ()

  : m_state (DISASSOC)

{}

MacStation::~MacStation ()

{}

bool 

MacStation::IsAssociated (void) const

{

  return m_state == GOT_ASSOC_TX_OK;

}

bool 

MacStation::IsWaitAssocTxOk (void) const

{

  return m_state == WAIT_ASSOC_TX_OK;

}

void 

MacStation::RecordWaitAssocTxOk (void)

{

  m_state = WAIT_ASSOC_TX_OK;

}

void 

MacStation::RecordGotAssocTxOk (void)

{

  m_state = GOT_ASSOC_TX_OK;

}

void 

MacStation::RecordGotAssocTxFailed (void)

{

  m_state = DISASSOC;

}

void 

MacStation::RecordDisassociated (void)

{

  m_state = DISASSOC;

}

void 

MacStation::Reset (void)

{

  m_modes.clear ();

  AddSupportedMode (GetStations ()->GetDefaultMode ());

}

void 

MacStation::AddSupportedMode (WifiMode mode)

{

  if (IsIn (mode))

    {

      return;

    }

  m_modes.push_back (mode);

}

bool

MacStation::IsIn (WifiMode mode) const

{

  for (SupportedModes::const_iterator i = m_modes.begin (); i != m_modes.end (); i++)

    {

      if ((*i) == mode)

        {

          return true;

        }

    }

  return false;

}

WifiMode

MacStation::GetControlAnswerMode (WifiMode reqMode)

{

  /**

   * see ieee 802.11e, section 9.6:

   * 

   * To allow the transmitting STA to calculate the contents of 

   * the Duration/ID field, a STA responding to a received frame 

   * shall transmit its Control Response frame (either CTS or ACK) 

   * frames, other than the Block-Ack control frame, at the highest 

   * rate in the BSSBasicRateSet parameter that is less than or equal 

   * to the rate of the immediately previous frame in the frame 

   * exchange sequence (as defined in 9.79.12) and that is of the

   * same modulation type as the received frame. If no rate in the 

   * basic rate set meets these conditions, then the control frame 

   * sent in response to a received frame shall be transmitted at 

   * the highest mandatory rate of the PHY that is less than or equal 

   * to the rate of the received frame, and that is of the same 

   * modulation type as the received frame. In addition, the Control 

   * Response frame shall be sent using the same PHY options as the

   * received frame, unless they conflict with the requirement to use 

   * the BSSBasicRateSet parameter.

   */

  WifiMode mode = GetStations ()->GetDefaultMode ();

  bool found = false;

  // First, search the BSS Basic Rate set

  for (MacStations::BasicModesIterator i = GetStations ()->BeginBasicModes (); 

       i != GetStations ()->EndBasicModes (); i++)

    {

      if (i->GetPhyRate () > mode.GetPhyRate () &&

          i->GetPhyRate () <= reqMode.GetPhyRate () &&

          i->GetModulationType () == reqMode.GetModulationType ())

        {

          mode = *i;

          found = true;

        }

    }

  // no need to search Mandatory rate set because it is included

  // within the Basic rate set.

  return mode;

}

WifiMode 

MacStation::GetCtsMode (WifiMode rtsMode)

{

  return GetControlAnswerMode (rtsMode);

}

WifiMode 

MacStation::GetAckMode (WifiMode dataMode)

{

  return GetControlAnswerMode (dataMode);

}

uint32_t 

MacStation::GetNSupportedModes (void) const

{

  return m_modes.size ();

}

WifiMode 

MacStation::GetSupportedMode (uint32_t i) const

{

  NS_ASSERT (i > 0);

  return m_modes[i-1];

}

} // namespace ns3