NS-3 based Named Data Networking (NDN) simulator
ndnSIM 2.5: NDN, CCN, CCNx, content centric networks
API Documentation
nfd::fw::Strategy Class Referenceabstract

represents a forwarding strategy More...

#include <strategy.hpp>

Inheritance diagram for nfd::fw::Strategy:
Collaboration diagram for nfd::fw::Strategy:

Classes

struct  ParsedInstanceName
 

Public Member Functions

 Strategy (Forwarder &forwarder)
 construct a strategy instance More...
 
virtual ~Strategy ()
 
const NamegetInstanceName () const
 
virtual void afterReceiveInterest (const Face &inFace, const Interest &interest, const shared_ptr< pit::Entry > &pitEntry)=0
 trigger after Interest is received More...
 
virtual void beforeSatisfyInterest (const shared_ptr< pit::Entry > &pitEntry, const Face &inFace, const Data &data)
 trigger before PIT entry is satisfied More...
 
virtual void afterContentStoreHit (const shared_ptr< pit::Entry > &pitEntry, const Face &inFace, const Data &data)
 trigger after a Data is matched in CS More...
 
virtual void afterReceiveData (const shared_ptr< pit::Entry > &pitEntry, const Face &inFace, const Data &data)
 trigger after Data is received More...
 
virtual void afterReceiveNack (const Face &inFace, const lp::Nack &nack, const shared_ptr< pit::Entry > &pitEntry)
 trigger after Nack is received More...
 
virtual void onDroppedInterest (const Face &outFace, const Interest &interest)
 trigger after Interest dropped for exceeding allowed retransmissions More...
 

Static Public Member Functions

template<typename S >
static void registerType (const Name &strategyName=S::getStrategyName())
 register a strategy type More...
 
static bool canCreate (const Name &instanceName)
 
static unique_ptr< Strategycreate (const Name &instanceName, Forwarder &forwarder)
 
static bool areSameType (const Name &instanceNameA, const Name &instanceNameB)
 
static std::set< NamelistRegistered ()
 
static const NamegetStrategyName ()
 

Protected Member Functions

void sendInterest (const shared_ptr< pit::Entry > &pitEntry, Face &outFace, const Interest &interest)
 send Interest to outFace More...
 
void sendData (const shared_ptr< pit::Entry > &pitEntry, const Data &data, const Face &outFace)
 send data to outFace More...
 
void sendDataToAll (const shared_ptr< pit::Entry > &pitEntry, const Face &inFace, const Data &data)
 send data to all matched and qualified faces More...
 
void rejectPendingInterest (const shared_ptr< pit::Entry > &pitEntry)
 schedule the PIT entry for immediate deletion More...
 
void sendNack (const shared_ptr< pit::Entry > &pitEntry, const Face &outFace, const lp::NackHeader &header)
 send Nack to outFace More...
 
void sendNacks (const shared_ptr< pit::Entry > &pitEntry, const lp::NackHeader &header, std::initializer_list< const Face *> exceptFaces=std::initializer_list< const Face *>())
 send Nack to every face that has an in-record, except those in exceptFaces More...
 
void setExpiryTimer (const shared_ptr< pit::Entry > &pitEntry, time::milliseconds duration)
 Schedule the PIT entry to be erased after duration. More...
 
const fib::EntrylookupFib (const pit::Entry &pitEntry) const
 performs a FIB lookup, considering Link object if present More...
 
MeasurementsAccessorgetMeasurements ()
 
FacegetFace (FaceId id) const
 
const FaceTablegetFaceTable () const
 
void setInstanceName (const Name &name)
 set strategy instance name More...
 

Static Protected Member Functions

static ParsedInstanceName parseInstanceName (const Name &input)
 parse a strategy instance name More...
 
static Name makeInstanceName (const Name &input, const Name &strategyName)
 construct a strategy instance name More...
 

Protected Attributes

signal::Signal< FaceTable, Face & > & afterAddFace
 
signal::Signal< FaceTable, Face & > & beforeRemoveFace
 

Detailed Description

represents a forwarding strategy

Definition at line 37 of file strategy.hpp.

Constructor & Destructor Documentation

◆ Strategy()

nfd::fw::Strategy::Strategy ( Forwarder forwarder)
explicit

construct a strategy instance

Parameters
forwardera reference to the forwarder, used to enable actions and accessors.
Note
Strategy subclass constructor should not retain a reference to the forwarder.

Definition at line 141 of file strategy.cpp.

◆ ~Strategy()

nfd::fw::Strategy::~Strategy ( )
virtualdefault

Member Function Documentation

◆ registerType()

template<typename S >
static void nfd::fw::Strategy::registerType ( const Name strategyName = S::getStrategyName())
inlinestatic

register a strategy type

Template Parameters
Ssubclass of Strategy
Parameters
strategyNamestrategy program name, must contain version
Note
It is permitted to register the same strategy type under multiple names, which is useful in tests and for creating aliases.

Definition at line 48 of file strategy.hpp.

◆ canCreate()

bool nfd::fw::Strategy::canCreate ( const Name instanceName)
static
Returns
whether a strategy instance can be created from instanceName
Parameters
instanceNamestrategy instance name, may contain version and parameters
Note
This function finds a strategy type using same rules as create , but does not attempt to construct an instance.

Definition at line 84 of file strategy.cpp.

◆ create()

unique_ptr< Strategy > nfd::fw::Strategy::create ( const Name instanceName,
Forwarder forwarder 
)
static
Returns
a strategy instance created from instanceName
Return values
nullptrif !canCreate(instanceName)
Exceptions
std::invalid_argumentstrategy type constructor does not accept specified version or parameters

Definition at line 90 of file strategy.cpp.

References NFD_LOG_DEBUG.

Referenced by nfd::strategy_choice::StrategyChoice::insert(), and nfd::strategy_choice::StrategyChoice::setDefaultStrategy().

◆ areSameType()

bool nfd::fw::Strategy::areSameType ( const Name instanceNameA,
const Name instanceNameB 
)
static
Returns
whether instanceNameA and instanceNameA will initiate same strategy type

Definition at line 106 of file strategy.cpp.

◆ listRegistered()

std::set< Name > nfd::fw::Strategy::listRegistered ( )
static
Returns
registered versioned strategy names

Definition at line 112 of file strategy.cpp.

◆ getStrategyName()

static const Name& nfd::fw::Strategy::getStrategyName ( )
static
Returns
strategy program name

The strategy name is defined by the strategy program. It must end with a version component.

◆ getInstanceName()

const Name& nfd::fw::Strategy::getInstanceName ( ) const
inline
Returns
strategy instance name

The instance name is assigned during instantiation. It contains a version component, and may have extra parameter components.

Definition at line 110 of file strategy.hpp.

Referenced by nfd::strategy_choice::Entry::getStrategyInstanceName(), and nfd::strategy_choice::StrategyChoice::insert().

◆ afterReceiveInterest()

virtual void nfd::fw::Strategy::afterReceiveInterest ( const Face inFace,
const Interest interest,
const shared_ptr< pit::Entry > &  pitEntry 
)
pure virtual

trigger after Interest is received

The Interest:

  • does not violate Scope
  • is not looped
  • cannot be satisfied by ContentStore
  • is under a namespace managed by this strategy

The PIT entry is set to expire after InterestLifetime has elapsed at each downstream.

The strategy should decide whether and where to forward this Interest.

  • If the strategy decides to forward this Interest, invoke sendInterest for each upstream, either now or shortly after via a scheduler event, but before PIT entry expires. Optionally, the strategy can invoke setExpiryTimer to adjust how long it would wait for a response.
  • If the strategy has already forwarded this Interest previously and decides to continue waiting, do nothing. Optionally, the strategy can invoke setExpiryTimer to adjust how long it would wait for a response.
  • If the strategy concludes that this Interest cannot be satisfied, invoke rejectPendingInterest to erase the PIT entry.
Warning
The strategy must not retain shared_ptr<pit::Entry>, otherwise undefined behavior may occur. However, the strategy is allowed to store weak_ptr<pit::Entry>.

Implemented in nfd::fw::BestRouteStrategy2, nfd::fw::AccessStrategy, nfd::fw::asf::AsfStrategy, nfd::fw::MulticastStrategy, nfd::fw::NccStrategy, and nfd::fw::BestRouteStrategyBase.

◆ beforeSatisfyInterest()

void nfd::fw::Strategy::beforeSatisfyInterest ( const shared_ptr< pit::Entry > &  pitEntry,
const Face inFace,
const Data data 
)
virtual

trigger before PIT entry is satisfied

This trigger is invoked when an incoming Data satisfies more than one PIT entry. The strategy can collect measurements information, but cannot manipulate Data forwarding. When an incoming Data satisfies only one PIT entry, afterReceiveData is invoked instead and given full control over Data forwarding. If a strategy does not override afterReceiveData, the default implementation invokes beforeSatisfyInterest.

Normally, PIT entries would be erased after receiving the first matching Data. If the strategy wishes to collect responses from additional upstream nodes, it should invoke setExpiryTimer within this function to prolong the PIT entry lifetime. If a Data arrives from another upstream during the extended PIT entry lifetime, this trigger will be invoked again. At that time, this function must invoke setExpiryTimer again to continue collecting more responses.

In this base class this method does nothing.

Warning
The strategy must not retain shared_ptr<pit::Entry>, otherwise undefined behavior may occur. However, the strategy is allowed to store weak_ptr<pit::Entry>.

Reimplemented in nfd::fw::AccessStrategy, nfd::fw::asf::AsfStrategy, and nfd::fw::NccStrategy.

Definition at line 152 of file strategy.cpp.

References nfd::face::Face::getId(), ndn::Data::getName(), and NFD_LOG_DEBUG.

Referenced by afterReceiveData().

◆ afterContentStoreHit()

void nfd::fw::Strategy::afterContentStoreHit ( const shared_ptr< pit::Entry > &  pitEntry,
const Face inFace,
const Data data 
)
virtual

trigger after a Data is matched in CS

In the base class this method sends data to inFace

Definition at line 160 of file strategy.cpp.

References nfd::face::Face::getId(), ndn::Data::getName(), NFD_LOG_DEBUG, and sendData().

◆ afterReceiveData()

void nfd::fw::Strategy::afterReceiveData ( const shared_ptr< pit::Entry > &  pitEntry,
const Face inFace,
const Data data 
)
virtual

trigger after Data is received

This trigger is invoked when an incoming Data satisfies exactly one PIT entry, and gives the strategy full control over Data forwarding.

When this trigger is invoked:

  • The Data has been verified to satisfy the PIT entry.
  • The PIT entry expiry timer is set to now

Within this function:

  • A strategy should return Data to downstream nodes via sendData or sendDataToAll.
  • A strategy can modify the Data as long as it still satisfies the PIT entry, such as adding or removing congestion marks.
  • A strategy can delay Data forwarding by prolonging the PIT entry lifetime via setExpiryTimer, and forward Data before the PIT entry is erased.
  • A strategy can collect measurements about the upstream.
  • A strategy can collect responses from additional upstream nodes by prolonging the PIT entry lifetime via setExpiryTimer every time a Data is received. Note that only one Data should be returned to each downstream node.

In the base class this method invokes beforeSatisfyInterest trigger and then returns the Data to downstream faces via sendDataToAll.

Definition at line 170 of file strategy.cpp.

References beforeSatisfyInterest(), nfd::face::Face::getId(), ndn::Data::getName(), NFD_LOG_DEBUG, and sendDataToAll().

◆ afterReceiveNack()

void nfd::fw::Strategy::afterReceiveNack ( const Face inFace,
const lp::Nack nack,
const shared_ptr< pit::Entry > &  pitEntry 
)
virtual

trigger after Nack is received

This trigger is invoked when an incoming Nack is received in response to an forwarded Interest. The Nack has been confirmed to be a response to the last Interest forwarded to that upstream, i.e. the PIT out-record exists and has a matching Nonce. The NackHeader has been recorded in the PIT out-record.

If the PIT entry is not yet satisfied, its expiry timer remains unchanged. Otherwise, the PIT entry normally would expire immediately after this function returns.

If the strategy wishes to collect responses from additional upstream nodes, it should invoke setExpiryTimer within this function to retain the PIT entry. If a Nack arrives from another upstream during the extended PIT entry lifetime, this trigger will be invoked again. At that time, this function must invoke setExpiryTimer again to continue collecting more responses.

In the base class this method does nothing.

Warning
The strategy must not retain shared_ptr<pit::Entry>, otherwise undefined behavior may occur. However, the strategy is allowed to store weak_ptr<pit::Entry>.

Reimplemented in nfd::fw::BestRouteStrategy2, nfd::fw::asf::AsfStrategy, and nfd::fw::MulticastStrategy.

Definition at line 182 of file strategy.cpp.

References nfd::face::Face::getId(), and NFD_LOG_DEBUG.

◆ onDroppedInterest()

void nfd::fw::Strategy::onDroppedInterest ( const Face outFace,
const Interest interest 
)
virtual

trigger after Interest dropped for exceeding allowed retransmissions

In the base class this method does nothing.

Definition at line 190 of file strategy.cpp.

References nfd::face::Face::getId(), ndn::Interest::getName(), and NFD_LOG_DEBUG.

◆ sendInterest()

void nfd::fw::Strategy::sendInterest ( const shared_ptr< pit::Entry > &  pitEntry,
Face outFace,
const Interest interest 
)
inlineprotected

send Interest to outFace

Parameters
pitEntryPIT entry
outFaceface through which to send out the Interest
interestthe Interest packet

Definition at line 241 of file strategy.hpp.

Referenced by nfd::fw::BestRouteStrategyBase::afterReceiveInterest(), nfd::fw::NccStrategy::afterReceiveInterest(), nfd::fw::MulticastStrategy::afterReceiveInterest(), nfd::fw::BestRouteStrategy2::afterReceiveInterest(), and nfd::fw::NccStrategy::doPropagate().

◆ sendData()

void nfd::fw::Strategy::sendData ( const shared_ptr< pit::Entry > &  pitEntry,
const Data data,
const Face outFace 
)
protected

send data to outFace

Parameters
pitEntryPIT entry
datathe Data packet
outFaceface through which to send out the Data

Definition at line 196 of file strategy.cpp.

Referenced by afterContentStoreHit(), and sendDataToAll().

◆ sendDataToAll()

void nfd::fw::Strategy::sendDataToAll ( const shared_ptr< pit::Entry > &  pitEntry,
const Face inFace,
const Data data 
)
protected

send data to all matched and qualified faces

A matched face is qualified if it is ad-hoc or it is NOT inFace

Parameters
pitEntryPIT entry
inFaceface through which the Data comes from
datathe Data packet

Definition at line 208 of file strategy.cpp.

References nfd::face::Face::getId(), ndn::nfd::LINK_TYPE_AD_HOC, ndn::time::steady_clock::now(), and sendData().

Referenced by afterReceiveData().

◆ rejectPendingInterest()

void nfd::fw::Strategy::rejectPendingInterest ( const shared_ptr< pit::Entry > &  pitEntry)
inlineprotected

schedule the PIT entry for immediate deletion

This helper function sets the PIT entry expiry time to zero. The strategy should invoke this function when it concludes that the Interest cannot be forwarded and it does not want to wait for responses from existing upstream nodes.

Definition at line 273 of file strategy.hpp.

References setExpiryTimer().

Referenced by nfd::fw::BestRouteStrategyBase::afterReceiveInterest(), nfd::fw::NccStrategy::afterReceiveInterest(), nfd::fw::MulticastStrategy::afterReceiveInterest(), nfd::fw::asf::AsfStrategy::afterReceiveInterest(), and nfd::fw::BestRouteStrategy2::afterReceiveInterest().

◆ sendNack()

void nfd::fw::Strategy::sendNack ( const shared_ptr< pit::Entry > &  pitEntry,
const Face outFace,
const lp::NackHeader header 
)
inlineprotected

send Nack to outFace

Parameters
pitEntryPIT entry
outFaceface through which to send out the Nack
headerNack header

The outFace must have a PIT in-record, otherwise this method has no effect.

Definition at line 286 of file strategy.hpp.

Referenced by nfd::fw::MulticastStrategy::afterReceiveInterest(), nfd::fw::BestRouteStrategy2::afterReceiveInterest(), and sendNacks().

◆ sendNacks()

void nfd::fw::Strategy::sendNacks ( const shared_ptr< pit::Entry > &  pitEntry,
const lp::NackHeader header,
std::initializer_list< const Face *>  exceptFaces = std::initializer_list<const Face*>() 
)
protected

send Nack to every face that has an in-record, except those in exceptFaces

Parameters
pitEntryPIT entry
headerNACK header
exceptFaceslist of faces that should be excluded from sending Nacks
Note
This is not an action, but a helper that invokes the sendNack action.

Definition at line 230 of file strategy.cpp.

References nfd::pit::FaceRecord::getFace(), and sendNack().

◆ setExpiryTimer()

void nfd::fw::Strategy::setExpiryTimer ( const shared_ptr< pit::Entry > &  pitEntry,
time::milliseconds  duration 
)
inlineprotected

Schedule the PIT entry to be erased after duration.

Definition at line 306 of file strategy.hpp.

Referenced by rejectPendingInterest().

◆ lookupFib()

◆ getMeasurements()

◆ getFace()

Face* nfd::fw::Strategy::getFace ( FaceId  id) const
inlineprotected

Definition at line 324 of file strategy.hpp.

References nfd::Forwarder::getFace().

Referenced by nfd::fw::NccStrategy::doPropagate().

◆ getFaceTable()

const FaceTable& nfd::fw::Strategy::getFaceTable ( ) const
inlineprotected

Definition at line 330 of file strategy.hpp.

References nfd::Forwarder::getFaceTable().

◆ parseInstanceName()

Strategy::ParsedInstanceName nfd::fw::Strategy::parseInstanceName ( const Name input)
staticprotected

◆ makeInstanceName()

Name nfd::fw::Strategy::makeInstanceName ( const Name input,
const Name strategyName 
)
staticprotected

construct a strategy instance name

Parameters
inputstrategy instance name, may contain version and parameters
strategyNamestrategy name with version but without parameters; typically this should be getStrategyName()

If input contains a version component, return input unchanged. Otherwise, return input plus the version component taken from strategyName. This allows a strategy instance to be constructed with an unversioned name, but its final instance name should contain the version.

Definition at line 132 of file strategy.cpp.

References ndn::Name::at(), ndn::name::Component::isVersion(), ns3::ndn::Name, ndn::Name::rbegin(), and ndn::Name::rend().

Referenced by nfd::fw::AccessStrategy::AccessStrategy(), nfd::fw::asf::AsfStrategy::AsfStrategy(), nfd::fw::BestRouteStrategy::BestRouteStrategy(), nfd::fw::BestRouteStrategy2::BestRouteStrategy2(), nfd::fw::ClientControlStrategy::ClientControlStrategy(), nfd::fw::MulticastStrategy::MulticastStrategy(), and nfd::fw::NccStrategy::NccStrategy().

◆ setInstanceName()

void nfd::fw::Strategy::setInstanceName ( const Name name)
inlineprotected

Member Data Documentation

◆ afterAddFace

signal::Signal<FaceTable, Face&>& nfd::fw::Strategy::afterAddFace
protected

Definition at line 383 of file strategy.hpp.

◆ beforeRemoveFace

signal::Signal<FaceTable, Face&>& nfd::fw::Strategy::beforeRemoveFace
protected

Definition at line 384 of file strategy.hpp.


The documentation for this class was generated from the following files: