nfd::fw::Strategy Class Referenceabstract

represents a forwarding strategy More...

#include <daemon/fw/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 ()
 
virtual void afterReceiveInterest (const Face &inFace, const Interest &interest, const shared_ptr< pit::Entry > &pitEntry)=0
 trigger after Interest 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 beforeExpirePendingInterest (const shared_ptr< pit::Entry > &pitEntry)
 trigger before PIT entry expires More...
 
virtual void beforeSatisfyInterest (const shared_ptr< pit::Entry > &pitEntry, const Face &inFace, const Data &data)
 trigger before PIT entry is satisfied More...
 
const Name & getInstanceName () const
 

Static Public Member Functions

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

Protected Member Functions

Face * getFace (FaceId id) const
 
const FaceTablegetFaceTable () const
 
MeasurementsAccessor & getMeasurements ()
 
const fib::EntrylookupFib (const pit::Entry &pitEntry) const
 performs a FIB lookup, considering Link object if present More...
 
void rejectPendingInterest (const shared_ptr< pit::Entry > &pitEntry)
 decide that a pending Interest cannot be forwarded More...
 
void sendInterest (const shared_ptr< pit::Entry > &pitEntry, Face &outFace, const Interest &interest)
 send Interest to outFace 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 setInstanceName (const Name &name)
 set strategy instance name More...
 

Static Protected Member Functions

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

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.

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

Member Function Documentation

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 strategy should decide whether and where to forward this Interest.

  • If the strategy decides to forward this Interest, invoke this->sendInterest one or more times, either now or shortly after
  • If strategy concludes that this Interest cannot be forwarded, invoke this->rejectPendingInterest so that PIT entry will be deleted shortly
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.

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.

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

Definition at line 166 of file strategy.cpp.

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.

void nfd::fw::Strategy::beforeExpirePendingInterest ( const shared_ptr< pit::Entry > &  pitEntry)
virtual

trigger before PIT entry expires

PIT entry expires when InterestLifetime has elapsed for all InRecords, and it is not satisfied by an incoming Data.

This trigger is not invoked for PIT entry already satisfied.

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>, although this isn't useful here because PIT entry would be deleted shortly after.

Definition at line 160 of file strategy.cpp.

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 the PIT entry. It can be invoked even if the PIT entry has already been satisfied.

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.

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.

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.

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

Definition at line 247 of file strategy.hpp.

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

Definition at line 253 of file strategy.hpp.

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.

MeasurementsAccessor& nfd::fw::Strategy::getMeasurements ( )
inlineprotected

Definition at line 241 of file strategy.hpp.

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.

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

Definition at line 112 of file strategy.cpp.

const fib::Entry & nfd::fw::Strategy::lookupFib ( const pit::Entry pitEntry) const
protected

performs a FIB lookup, considering Link object if present

Definition at line 196 of file strategy.cpp.

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.

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

parse a strategy instance name

Parameters
inputstrategy instance name, may contain version and parameters
Exceptions
std::invalid_argumentinput format is unacceptable

Definition at line 121 of file strategy.cpp.

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.

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

decide that a pending Interest cannot be forwarded

Parameters
pitEntryPIT entry

This shall not be called if the pending Interest has been forwarded earlier, and does not need to be resent now.

Definition at line 204 of file strategy.hpp.

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 191 of file strategy.hpp.

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 217 of file strategy.hpp.

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 174 of file strategy.cpp.

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

set strategy instance name

Note
This must be called by strategy subclass constructor.

Definition at line 290 of file strategy.hpp.

Member Data Documentation

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

Definition at line 306 of file strategy.hpp.

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

Definition at line 307 of file strategy.hpp.