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

     2 /*

     3  * Copyright (c) 2005, 2006 INRIA

     4  * All rights reserved.

     5  *

     6  * This program is free software; you can redistribute it and/or modify

     7  * it under the terms of the GNU General Public License version 2 as 

     8  * published by the Free Software Foundation;

     9  *

    10  * This program is distributed in the hope that it will be useful,

    11  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    13  * GNU General Public License for more details.

    14  *

    15  * You should have received a copy of the GNU General Public License

    16  * along with this program; if not, write to the Free Software

    17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    18  *

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

    20  */

    21 #ifndef MAC_LOW_H

    22 #define MAC_LOW_H

    23 

    24 #include <vector>

    25 #include <stdint.h>

    26 

    27 #include "wifi-mac-header.h"

    28 #include "wifi-mode.h"

    29 #include "ns3/mac48-address.h"

    30 #include "ns3/callback.h"

    31 #include "ns3/callback-trace-source.h"

    32 #include "ns3/event-id.h"

    33 #include "ns3/packet.h"

    34 #include "ns3/nstime.h"

    35 

    36 namespace ns3 {

    37 

    38 class WifiNetDevice;

    39 class WifiPhy;

    40 class PacketLogger;

    41 class MacStations;

    42 class MacStation;

    43 class MacParameters;

    44 

    45 class MacLowTransmissionListener {

    46 public:

    47   MacLowTransmissionListener ();

    48   virtual ~MacLowTransmissionListener ();

    49 

    50   virtual void GotCts (double snr, WifiMode txMode) = 0;

    51   virtual void MissedCts (void) = 0;

    52   /* Do not rely on the gotAck method to be

    53    * given valid parameters when SuperFastAck is

    54    * enabled.

    55    */

    56   virtual void GotAck (double snr, WifiMode txMode) = 0;

    57   virtual void MissedAck (void) = 0;

    58   virtual void StartNext (void) = 0;

    59 

    60   /* Invoked if this transmission was canceled 

    61    * one way or another. When this method is invoked,

    62    * you can assume that the packet has not been passed

    63    * down the stack to the PHY. You are responsible

    64    * for freeing the packet if you want to.

    65    */

    66   virtual void Cancel (void) = 0;

    67 };

    68 

    69 

    70 class MacLowNavListener {

    71 public:

    72   MacLowNavListener ();

    73   virtual ~MacLowNavListener ();

    74   virtual void NavStart (Time now, Time duration) = 0;

    75   virtual void NavContinue (Time now, Time duration) = 0;

    76   virtual void NavReset (Time now, Time duration) = 0;

    77 };

    78 

    79 class MacLowTransmissionParameters {

    80 public:

    81   MacLowTransmissionParameters ();

    82     

    83   /* If ACK is enabled, we wait ACKTimeout for an ACK.

    84    */

    85   void EnableAck (void);

    86   /* If FastAck is enabled, we:

    87    *   - wait PIFS after end-of-tx. If idle, report

    88    *     FastAckMissed.

    89    *   - if busy at end-of-tx+PIFS, wait end-of-rx

    90    *   - if Ack ok at end-of-rx, report FastAck ok.

    91    *   - if Ack not ok at end-of-rx, report FastAckMissed

    92    *     at end-of-rx+SIFS.

    93    * This is really complicated but it is needed for

    94    * proper HCCA support.

    95    */

    96   void EnableFastAck (void);

    97   /* If SuperFastAck is enabled, we:

    98    *   - if busy at end-of-tx+PIFS, report gotAck

    99    *   - if idle at end-of-tx+PIFS, report missedAck

   100    */

   101   void EnableSuperFastAck (void);

   102   /* If RTS is enabled, we wait CTSTimeout for a CTS.

   103    * Otherwise, no RTS is sent.

   104    */

   105   void EnableRts (void);

   106   /* If NextData is enabled, we add the transmission duration

   107    * of the nextData to the durationId and we notify the

   108    * transmissionListener at the end of the current

   109    * transmission + SIFS.

   110    */

   111   void EnableNextData (uint32_t size);

   112   

   113   /* If we enable this, we ignore all other durationId 

   114    * calculation and simply force the packet's durationId

   115    * field to this value.

   116    */

   117   void EnableOverrideDurationId (Time durationId);

   118   

   119   void DisableAck (void);

   120   void DisableRts (void);

   121   void DisableNextData (void);

   122   void DisableOverrideDurationId (void);

   123 

   124   bool MustWaitAck (void) const;

   125   bool MustWaitNormalAck (void) const;

   126   bool MustWaitFastAck (void) const;

   127   bool MustWaitSuperFastAck (void) const;

   128   bool MustSendRts (void) const;

   129   bool HasDurationId (void) const;

   130   Time GetDurationId (void) const;

   131   bool HasNextPacket (void) const;

   132   uint32_t GetNextPacketSize (void) const;

   133 

   134 private:

   135   uint32_t m_nextSize;

   136   enum {

   137     ACK_NONE,

   138     ACK_NORMAL,

   139     ACK_FAST,

   140     ACK_SUPER_FAST

   141   } m_waitAck;

   142   bool m_sendRts;

   143   Time m_overrideDurationId;

   144 };

   145 

   146 

   147 class MacLow {

   148 public:

   149   typedef Callback<void, Packet , WifiMacHeader const*> MacLowRxCallback;

   150 

   151   MacLow ();

   152   ~MacLow ();

   153 

   154   void SetInterface (Ptr<WifiNetDevice> interface);

   155   void SetPhy (WifiPhy *phy);

   156   void SetStations (MacStations *stations);

   157   void SetParameters (MacParameters *parameters);

   158   void SetRxCallback (MacLowRxCallback callback);

   159   void RegisterNavListener (MacLowNavListener *listener);

   160 

   161   /* This transmission time includes the time required for

   162    * the next packet transmission if one was selected.

   163    */

   164   Time CalculateTransmissionTime (uint32_t payloadSize,

   165                                   Mac48Address to,

   166                                   MacLowTransmissionParameters const&parameters) const;

   167 

   168   /* start the transmission of the currently-stored data. */

   169   void StartTransmission (Packet packet, 

   170                           WifiMacHeader const*hdr, 

   171                           MacLowTransmissionParameters parameters,

   172                           MacLowTransmissionListener *listener);

   173 

   174   void ReceiveOk (Packet const packet, double rxSnr, WifiMode txMode, WifiMode headerMode);

   175   void ReceiveError (Packet const packet, double rxSnr);

   176 private:

   177   void CancelAllEvents (void);

   178   uint32_t GetAckSize (void) const;

   179   uint32_t GetRtsSize (void) const;

   180   uint32_t GetCtsSize (void) const;

   181   Time GetSifs (void) const;

   182   Time GetPifs (void) const;

   183   Time GetAckTimeout (void) const;

   184   Time GetCtsTimeout (void) const;

   185   uint32_t GetCurrentSize (void) const;

   186   Time NowUs (void) const;

   187   MacStation *GetStation (Mac48Address to) const;

   188   void ForwardDown (Packet const packet, WifiMacHeader const *hdr, 

   189                     WifiMode txMode);

   190   Time CalculateOverallTxTime (uint32_t size,

   191                                Mac48Address to,

   192                                MacLowTransmissionParameters const &params) const;

   193   WifiMode GetRtsTxMode (Mac48Address to) const;

   194   WifiMode GetDataTxMode (Mac48Address to, uint32_t size) const;

   195   WifiMode GetCtsTxModeForRts (Mac48Address to, WifiMode rtsTxMode) const;

   196   WifiMode GetAckTxModeForData (Mac48Address to, WifiMode dataTxMode) const;

   197   void NotifyNav (Time at, WifiMacHeader const*hdr);

   198   bool IsNavZero (Time at);

   199   void MaybeCancelPrevious (void);

   200   

   201   void NormalAckTimeout (void);

   202   void FastAckTimeout (void);

   203   void SuperFastAckTimeout (void);

   204   void FastAckFailedTimeout (void);

   205   void CtsTimeout (void);

   206   void SendCtsAfterRts (Mac48Address source, Time duration, WifiMode txMode, double rtsSnr);

   207   void SendAckAfterData (Mac48Address source, Time duration, WifiMode txMode, double rtsSnr);

   208   void SendDataAfterCts (Mac48Address source, Time duration, WifiMode txMode);

   209   void WaitSifsAfterEndTx (void);

   210 

   211   void SendRtsForPacket (void);

   212   void SendDataPacket (void);

   213   void SendCurrentTxPacket (void);

   214   void StartDataTxTimers (void);

   215 

   216   Ptr<WifiNetDevice> m_interface;

   217   WifiPhy *m_phy;

   218   MacStations *m_stations;

   219   MacParameters *m_parameters;

   220   MacLowRxCallback m_rxCallback;

   221   typedef std::vector<MacLowNavListener *>::const_iterator NavListenersCI;

   222   typedef std::vector<MacLowNavListener *> NavListeners;

   223   NavListeners m_navListeners;

   224 

   225   EventId m_normalAckTimeoutEvent;

   226   EventId m_fastAckTimeoutEvent;

   227   EventId m_superFastAckTimeoutEvent;

   228   EventId m_fastAckFailedTimeoutEvent;

   229   EventId m_ctsTimeoutEvent;

   230   EventId m_sendCtsEvent;

   231   EventId m_sendAckEvent;

   232   EventId m_sendDataEvent;

   233   EventId m_waitSifsEvent;

   234 

   235   Packet m_currentPacket;

   236   bool m_hasCurrent;

   237   WifiMacHeader m_currentHdr;

   238   MacLowTransmissionParameters m_txParams;

   239   MacLowTransmissionListener *m_listener;

   240 

   241   Time m_lastNavStart;

   242   Time m_lastNavDuration;

   243 

   244   CallbackTraceSource<Packet> m_dropError;

   245 };

   246 

   247 }; // namespace ns3

   248 

   249 #endif /* MAC_LOW_H */