A Discrete-Event Network Simulator
API
msdu-aggregator.cc
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1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
2 /*
3  * Copyright (c) 2009 MIRKO BANCHI
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation;
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  *
18  * Author: Mirko Banchi <mk.banchi@gmail.com>
19  * Stefano Avallone <stavallo@unina.it>
20  */
21 
22 #include "ns3/log.h"
23 #include "ns3/packet.h"
24 #include "msdu-aggregator.h"
25 #include "qos-txop.h"
27 #include "ns3/ht-capabilities.h"
28 #include "regular-wifi-mac.h"
29 #include "wifi-mac-queue.h"
30 #include "wifi-mac-trailer.h"
31 #include "ns3/ht-frame-exchange-manager.h"
32 #include "wifi-tx-parameters.h"
33 #include <algorithm>
34 
35 namespace ns3 {
36 
37 NS_LOG_COMPONENT_DEFINE ("MsduAggregator");
38 
39 NS_OBJECT_ENSURE_REGISTERED (MsduAggregator);
40 
41 TypeId
43 {
44  static TypeId tid = TypeId ("ns3::MsduAggregator")
45  .SetParent<Object> ()
46  .SetGroupName ("Wifi")
47  .AddConstructor<MsduAggregator> ()
48  ;
49  return tid;
50 }
51 
53 {
54 }
55 
57 {
58 }
59 
60 void
62 {
63  m_mac = 0;
64  m_htFem = 0;
66 }
67 
68 void
70 {
71  NS_LOG_FUNCTION (this << mac);
72  m_mac = mac;
73  m_htFem = DynamicCast<HtFrameExchangeManager> (m_mac->GetFrameExchangeManager ());
74 }
75 
76 uint16_t
77 MsduAggregator::GetSizeIfAggregated (uint16_t msduSize, uint16_t amsduSize)
78 {
79  NS_LOG_FUNCTION (msduSize << amsduSize);
80 
81  // the size of the A-MSDU subframe header is 14 bytes: DA (6), SA (6) and Length (2)
82  return amsduSize + CalculatePadding (amsduSize) + 14 + msduSize;
83 }
84 
87  Time availableTime) const
88 {
89  NS_LOG_FUNCTION (this << *peekedItem << &txParams << availableTime);
90 
91  Ptr<WifiMacQueue> queue = m_mac->GetTxopQueue (peekedItem->GetQueueAc ());
92 
93  uint8_t tid = peekedItem->GetHeader ().GetQosTid ();
94  Mac48Address recipient = peekedItem->GetHeader ().GetAddr1 ();
95 
96  /* "The Address 1 field of an MPDU carrying an A-MSDU shall be set to an
97  * individual address or to the GCR concealment address" (Section 10.12
98  * of 802.11-2016)
99  */
100  NS_ABORT_MSG_IF (recipient.IsBroadcast (), "Recipient address is broadcast");
101 
102  /* "A STA shall not transmit an A-MSDU within a QoS Data frame under a block
103  * ack agreement unless the recipient indicates support for A-MSDU by setting
104  * the A-MSDU Supported field to 1 in its BlockAck Parameter Set field of the
105  * ADDBA Response frame" (Section 10.12 of 802.11-2016)
106  */
107  // No check required for now, as we always set the A-MSDU Supported field to 1
108 
109  // TODO Add support for the Max Number Of MSDUs In A-MSDU field in the Extended
110  // Capabilities element sent by the recipient
111 
112  NS_ASSERT (m_htFem != 0);
113 
114  if (GetMaxAmsduSize (recipient, tid, txParams.m_txVector.GetModulationClass ()) == 0)
115  {
116  NS_LOG_DEBUG ("A-MSDU aggregation disabled");
117  return nullptr;
118  }
119 
120  Ptr<WifiMacQueueItem> amsdu = peekedItem->GetItem (); // amsdu points to the peeked MPDU, but it's non-const
121  uint8_t nMsdu = 1;
122  peekedItem = queue->PeekByTidAndAddress (tid, recipient, peekedItem);
123 
124  while (peekedItem != nullptr
125  && m_htFem->TryAggregateMsdu (peekedItem, txParams, availableTime))
126  {
127  // find the next MPDU before dequeuing the current one
128  Ptr<const WifiMacQueueItem> msdu = peekedItem;
129  peekedItem = queue->PeekByTidAndAddress (tid, recipient, peekedItem);
130  queue->DequeueIfQueued (msdu);
131 
132  // perform A-MSDU aggregation
133  queue->Transform (amsdu, [&msdu](Ptr<WifiMacQueueItem> amsdu)
134  {
135  amsdu->Aggregate (msdu);
136  });
137 
138  nMsdu++;
139  }
140 
141  if (nMsdu == 1)
142  {
143  NS_LOG_DEBUG ("Aggregation failed (could not aggregate at least two MSDUs)");
144  return nullptr;
145  }
146 
147  // Aggregation succeeded
148  return amsdu;
149 }
150 
151 uint8_t
153 {
154  return (4 - (amsduSize % 4 )) % 4;
155 }
156 
157 uint16_t
159  WifiModulationClass modulation) const
160 {
161  NS_LOG_FUNCTION (this << recipient << +tid << modulation);
162 
163  AcIndex ac = QosUtilsMapTidToAc (tid);
164 
165  // Find the A-MSDU max size configured on this device
166  uint16_t maxAmsduSize = m_mac->GetMaxAmsduSize (ac);
167 
168  if (maxAmsduSize == 0)
169  {
170  NS_LOG_DEBUG ("A-MSDU Aggregation is disabled on this station for AC " << ac);
171  return 0;
172  }
173 
174  Ptr<WifiRemoteStationManager> stationManager = m_mac->GetWifiRemoteStationManager ();
175  NS_ASSERT (stationManager);
176 
177  // Retrieve the Capabilities elements advertised by the recipient
178  Ptr<const VhtCapabilities> vhtCapabilities = stationManager->GetStationVhtCapabilities (recipient);
179  Ptr<const HtCapabilities> htCapabilities = stationManager->GetStationHtCapabilities (recipient);
180 
181  if (!htCapabilities)
182  {
183  /* "A non-DMG STA shall not transmit an A-MSDU to a STA from which it has
184  * not received a frame containing an HT Capabilities element" (Section
185  * 10.12 of 802.11-2016)
186  */
187  NS_LOG_DEBUG ("A-MSDU Aggregation disabled because the recipient did not"
188  " send an HT Capabilities element");
189  return 0;
190  }
191 
192  // Determine the constraint imposed by the recipient based on the PPDU
193  // format used to transmit the A-MSDU
194  if (modulation >= WIFI_MOD_CLASS_VHT)
195  {
196  // the maximum A-MSDU size is indirectly constrained by the maximum MPDU
197  // size supported by the recipient and advertised in the VHT Capabilities
198  // element (see Table 9-19 of 802.11-2016 as amended by 802.11ax)
199  NS_ABORT_MSG_IF (!vhtCapabilities, "VHT Capabilities element not received");
200 
201  maxAmsduSize = std::min (maxAmsduSize, static_cast<uint16_t>(vhtCapabilities->GetMaxMpduLength () - 56));
202  }
203  else if (modulation == WIFI_MOD_CLASS_HT)
204  {
205  // the maximum A-MSDU size is constrained by the maximum A-MSDU size
206  // supported by the recipient and advertised in the HT Capabilities
207  // element (see Table 9-19 of 802.11-2016)
208 
209  maxAmsduSize = std::min (maxAmsduSize, htCapabilities->GetMaxAmsduLength ());
210  }
211  else // non-HT PPDU
212  {
213  // the maximum A-MSDU size is indirectly constrained by the maximum PSDU size
214  // supported by the recipient (see Table 9-19 of 802.11-2016)
215 
216  maxAmsduSize = std::min (maxAmsduSize, static_cast<uint16_t>(3839));
217  }
218 
219  return maxAmsduSize;
220 }
221 
224 {
227 
229  Ptr<Packet> extractedMsdu = Create<Packet> ();
230  uint32_t maxSize = aggregatedPacket->GetSize ();
231  uint16_t extractedLength;
232  uint8_t padding;
233  uint32_t deserialized = 0;
234 
235  while (deserialized < maxSize)
236  {
237  deserialized += aggregatedPacket->RemoveHeader (hdr);
238  extractedLength = hdr.GetLength ();
239  extractedMsdu = aggregatedPacket->CreateFragment (0, static_cast<uint32_t> (extractedLength));
240  aggregatedPacket->RemoveAtStart (extractedLength);
241  deserialized += extractedLength;
242 
243  padding = (4 - ((extractedLength + 14) % 4 )) % 4;
244 
245  if (padding > 0 && deserialized < maxSize)
246  {
247  aggregatedPacket->RemoveAtStart (padding);
248  deserialized += padding;
249  }
250 
251  std::pair<Ptr<const Packet>, AmsduSubframeHeader> packetHdr (extractedMsdu, hdr);
252  set.push_back (packetHdr);
253  }
254  NS_LOG_INFO ("Deaggreated A-MSDU: extracted " << set.size () << " MSDUs");
255  return set;
256 }
257 
258 } //namespace ns3
ns3::TypeId
a unique identifier for an interface.
Definition: type-id.h:59
NS_LOG_COMPONENT_DEFINE
#define NS_LOG_COMPONENT_DEFINE(name)
Define a Log component with a specific name.
Definition: log.h:205
ns3::MsduAggregator::GetTypeId
static TypeId GetTypeId(void)
Get the type ID.
Definition: msdu-aggregator.cc:42
ns3::WifiMacQueueItem::Aggregate
void Aggregate(Ptr< const WifiMacQueueItem > msdu)
Aggregate the MSDU contained in the given MPDU to this MPDU (thus constituting an A-MSDU).
Definition: wifi-mac-queue-item.cc:123
NS_OBJECT_ENSURE_REGISTERED
#define NS_OBJECT_ENSURE_REGISTERED(type)
Register an Object subclass with the TypeId system.
Definition: object-base.h:45
NS_ASSERT
#define NS_ASSERT(condition)
At runtime, in debugging builds, if this condition is not true, the program prints the source file,...
Definition: assert.h:67
ns3::MsduAggregator::CalculatePadding
static uint8_t CalculatePadding(uint16_t amsduSize)
Calculate how much padding must be added to the end of an A-MSDU of the given size if a new MSDU is a...
Definition: msdu-aggregator.cc:152
min
#define min(a, b)
Definition: 80211b.c:42
regular-wifi-mac.h
ns3::AmsduSubframeHeader::GetLength
uint16_t GetLength(void) const
Get length function.
Definition: amsdu-subframe-header.cc:115
ns3::Packet::GetSize
uint32_t GetSize(void) const
Returns the the size in bytes of the packet (including the zero-filled initial payload).
Definition: packet.h:852
ns3::Packet::CreateFragment
Ptr< Packet > CreateFragment(uint32_t start, uint32_t length) const
Create a new packet which contains a fragment of the original packet.
Definition: packet.cc:227
wifi-tx-parameters.h
ns3
Every class exported by the ns3 library is enclosed in the ns3 namespace.
ns3::MsduAggregator::m_htFem
Ptr< HtFrameExchangeManager > m_htFem
the HT Frame Exchange Manager of this station
Definition: msdu-aggregator.h:146
ns3::WIFI_MOD_CLASS_HT
@ WIFI_MOD_CLASS_HT
HT (Clause 19)
Definition: wifi-phy-common.h:130
ns3::MsduAggregator::DoDispose
void DoDispose() override
Destructor implementation.
Definition: msdu-aggregator.cc:61
ns3::MsduAggregator::~MsduAggregator
virtual ~MsduAggregator()
Definition: msdu-aggregator.cc:56
qos-txop.h
wifi-remote-station-manager.h
ns3::WifiMacQueueItem::DeaggregatedMsdus
std::list< std::pair< Ptr< const Packet >, AmsduSubframeHeader > > DeaggregatedMsdus
DeaggregatedMsdus typedef.
Definition: wifi-mac-queue-item.h:135
ns3::AmsduSubframeHeader
Headers for A-MSDU subframes.
Definition: amsdu-subframe-header.h:34
ns3::Mac48Address
an EUI-48 address
Definition: mac48-address.h:44
third.mac
mac
Definition: third.py:99
ns3::WifiTxParameters
This class stores the TX parameters (TX vector, protection mechanism, acknowledgment mechanism,...
Definition: wifi-tx-parameters.h:45
ns3::TypeId::SetParent
TypeId SetParent(TypeId tid)
Set the parent TypeId.
Definition: type-id.cc:923
wifi-mac-queue.h
ns3::Ptr
Smart pointer class similar to boost::intrusive_ptr.
Definition: ptr.h:74
ns3::WifiRemoteStationManager::GetStationHtCapabilities
Ptr< const HtCapabilities > GetStationHtCapabilities(Mac48Address from)
Return the HT capabilities sent by the remote station.
Definition: wifi-remote-station-manager.cc:1418
ns3::WifiTxVector::GetModulationClass
WifiModulationClass GetModulationClass(void) const
Get the modulation class specified by this TXVECTOR.
Definition: wifi-tx-vector.cc:128
ns3::Packet::RemoveAtStart
void RemoveAtStart(uint32_t size)
Remove size bytes from the start of the current packet.
Definition: packet.cc:362
ns3::Object
A base class which provides memory management and object aggregation.
Definition: object.h:88
NS_LOG_INFO
#define NS_LOG_INFO(msg)
Use NS_LOG to output a message of level LOG_INFO.
Definition: log.h:281
ns3::QosUtilsMapTidToAc
AcIndex QosUtilsMapTidToAc(uint8_t tid)
Maps TID (Traffic ID) to Access classes.
Definition: qos-utils.cc:126
ns3::Mac48Address::IsBroadcast
bool IsBroadcast(void) const
Definition: mac48-address.cc:158
ns3::Packet::RemoveHeader
uint32_t RemoveHeader(Header &header)
Deserialize and remove the header from the internal buffer.
Definition: packet.cc:280
ns3::Time
Simulation virtual time values and global simulation resolution.
Definition: nstime.h:104
NS_ABORT_MSG_IF
#define NS_ABORT_MSG_IF(cond, msg)
Abnormal program termination if a condition is true, with a message.
Definition: abort.h:108
ns3::WifiRemoteStationManager::GetStationVhtCapabilities
Ptr< const VhtCapabilities > GetStationVhtCapabilities(Mac48Address from)
Return the VHT capabilities sent by the remote station.
Definition: wifi-remote-station-manager.cc:1424
msdu-aggregator.h
ns3::MsduAggregator::m_mac
Ptr< RegularWifiMac > m_mac
the MAC of this station
Definition: msdu-aggregator.h:145
NS_LOG_FUNCTION_NOARGS
#define NS_LOG_FUNCTION_NOARGS()
Output the name of the function.
Definition: log-macros-enabled.h:209
NS_LOG_DEBUG
#define NS_LOG_DEBUG(msg)
Use NS_LOG to output a message of level LOG_DEBUG.
Definition: log.h:273
ns3::WifiTxParameters::m_txVector
WifiTxVector m_txVector
TXVECTOR of the frame being prepared.
Definition: wifi-tx-parameters.h:62
ns3::MsduAggregator::GetSizeIfAggregated
static uint16_t GetSizeIfAggregated(uint16_t msduSize, uint16_t amsduSize)
Compute the size of the A-MSDU resulting from the aggregation of an MSDU of size msduSize and an A-MS...
Definition: msdu-aggregator.cc:77
ns3::MsduAggregator::Deaggregate
static WifiMacQueueItem::DeaggregatedMsdus Deaggregate(Ptr< Packet > aggregatedPacket)
Definition: msdu-aggregator.cc:223
ns3::MsduAggregator
Aggregator used to construct A-MSDUs.
Definition: msdu-aggregator.h:45
ns3::AcIndex
AcIndex
This enumeration defines the Access Categories as an enumeration with values corresponding to the AC ...
Definition: qos-utils.h:71
NS_LOG_FUNCTION
#define NS_LOG_FUNCTION(parameters)
If log level LOG_FUNCTION is enabled, this macro will output all input parameters separated by ",...
Definition: log-macros-enabled.h:244
ns3::MsduAggregator::SetWifiMac
void SetWifiMac(const Ptr< RegularWifiMac > mac)
Set the MAC layer to use.
Definition: msdu-aggregator.cc:69
ns3::WIFI_MOD_CLASS_VHT
@ WIFI_MOD_CLASS_VHT
VHT (Clause 22)
Definition: wifi-phy-common.h:131
ns3::MsduAggregator::GetMaxAmsduSize
uint16_t GetMaxAmsduSize(Mac48Address recipient, uint8_t tid, WifiModulationClass modulation) const
Determine the maximum size for an A-MSDU of the given TID that can be sent to the given receiver when...
Definition: msdu-aggregator.cc:158
ns3::MsduAggregator::GetNextAmsdu
Ptr< WifiMacQueueItem > GetNextAmsdu(Ptr< const WifiMacQueueItem > peekedItem, WifiTxParameters &txParams, Time availableTime) const
Attempt to aggregate other MSDUs to the given A-MSDU while meeting the following constraints:
Definition: msdu-aggregator.cc:86
wifi-mac-trailer.h
ns3::Object::DoDispose
virtual void DoDispose(void)
Destructor implementation.
Definition: object.cc:346
ns3::WifiModulationClass
WifiModulationClass
This enumeration defines the modulation classes per (Table 10-6 "Modulation classes"; IEEE 802....
Definition: wifi-phy-common.h:122
ns3::MsduAggregator::MsduAggregator
MsduAggregator()
Definition: msdu-aggregator.cc:52