/* -*- 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)
{
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)
{
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);
rates.AddSupportedRate (mode.GetDataRate ());
//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 two lowest mandatory rates are part of the BSSBasicRateSet
if (mode.IsMandatory ()
&& ((mode.GetModulationClass () != WIFI_MOD_CLASS_DSSS) || mode == WifiPhy::GetDsssRate1Mbps () || mode == WifiPhy::GetDsssRate2Mbps ()))
{
m_stationManager->AddBasicMode (mode);
}
}
//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;
}
HtCapabilities
ApWifiMac::GetHtCapabilities (void) const
{
HtCapabilities capabilities;
capabilities.SetHtSupported (1);
capabilities.SetLdpc (m_phy->GetLdpc ());
capabilities.SetShortGuardInterval20 (m_phy->GetGuardInterval ());
capabilities.SetGreenfield (m_phy->GetGreenfield ());
for (uint8_t i = 0; i < m_phy->GetNMcs (); i++)
{
capabilities.SetRxMcsBitmask (m_phy->GetMcs (i));
}
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)
{
probe.SetHtCapabilities (GetHtCapabilities ());
hdr.SetNoOrder ();
}
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)
{
assoc.SetHtCapabilities (GetHtCapabilities ());
hdr.SetNoOrder ();
}
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 ());
if (m_htSupported)
{
beacon.SetHtCapabilities (GetHtCapabilities ());
hdr.SetNoOrder ();
}
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 (m_htSupported)
{
//check that the STA supports all MCSs in Basic MCS Set
HtCapabilities htcapabilities = assocReq.GetHtCapabilities ();
for (uint32_t i = 0; i < m_stationManager->GetNBasicMcs (); i++)
{
uint8_t mcs = m_stationManager->GetBasicMcs (i);
if (!htcapabilities.IsSupportedMcs (mcs))
{
problem = true;
break;
}
}
}
if (problem)
{
//One of the Basic Rate set mode is not
//supported by the station. So, we return an assoc
//response with an error status.
SendAssocResp (hdr->GetAddr2 (), false);
}
else
{
//station supports all rates in Basic Rate Set.
//record all its supported modes in its associated WifiRemoteStation
for (uint32_t j = 0; j < m_phy->GetNModes (); j++)
{
WifiMode mode = m_phy->GetMode (j);
if (rates.IsSupportedRate (mode.GetDataRate ()))
{
m_stationManager->AddSupportedMode (from, mode);
}
}
if (m_htSupported)
{
HtCapabilities htcapabilities = assocReq.GetHtCapabilities ();
m_stationManager->AddStationHtCapabilities (from,htcapabilities);
for (uint32_t j = 0; j < m_phy->GetNMcs (); j++)
{
uint8_t mcs = m_phy->GetMcs (j);
if (htcapabilities.IsSupportedMcs (mcs))
{
m_stationManager->AddSupportedMcs (from, mcs);
}
}
}
m_stationManager->RecordWaitAssocTxOk (from);
//send assoc response with success status.
SendAssocResp (hdr->GetAddr2 (), true);
}
return;
}
else if (hdr->IsDisassociation ())
{
m_stationManager->RecordDisassociated (from);
return;
}
}
}
//Invoke the receive handler of our parent class to deal with any
//other frames. Specifically, this will handle Block Ack-related
//Management Action frames.
RegularWifiMac::Receive (packet, hdr);
}
void
ApWifiMac::DeaggregateAmsduAndForward (Ptr<Packet> aggregatedPacket,
const WifiMacHeader *hdr)
{
NS_LOG_FUNCTION (this << aggregatedPacket << hdr);
MsduAggregator::DeaggregatedMsdus packets =
MsduAggregator::Deaggregate (aggregatedPacket);
for (MsduAggregator::DeaggregatedMsdusCI i = packets.begin ();
i != packets.end (); ++i)
{
if ((*i).second.GetDestinationAddr () == GetAddress ())
{
ForwardUp ((*i).first, (*i).second.GetSourceAddr (),
(*i).second.GetDestinationAddr ());
}
else
{
Mac48Address from = (*i).second.GetSourceAddr ();
Mac48Address to = (*i).second.GetDestinationAddr ();
NS_LOG_DEBUG ("forwarding QoS frame from=" << from << ", to=" << to);
ForwardDown ((*i).first, from, to, hdr->GetQosTid ());
}
}
}
void
ApWifiMac::DoInitialize (void)
{
NS_LOG_FUNCTION (this);
m_beaconDca->Initialize ();
m_beaconEvent.Cancel ();
if (m_enableBeaconGeneration)
{
if (m_enableBeaconJitter)
{
int64_t jitter = m_beaconJitter->GetValue (0, m_beaconInterval.GetMicroSeconds ());
NS_LOG_DEBUG ("Scheduling initial beacon for access point " << GetAddress () << " at time " << jitter << " microseconds");
m_beaconEvent = Simulator::Schedule (MicroSeconds (jitter), &ApWifiMac::SendOneBeacon, this);
}
else
{
NS_LOG_DEBUG ("Scheduling initial beacon for access point " << GetAddress () << " at time 0");
m_beaconEvent = Simulator::ScheduleNow (&ApWifiMac::SendOneBeacon, this);
}
}
RegularWifiMac::DoInitialize ();
}
} //namespace ns3