provides for reliable sending and receiving of link-layer packets More...

#include <lp-reliability.hpp>

Inheritance diagram for nfd::face::LpReliability:

Collaboration diagram for nfd::face::LpReliability:

[legend]

Classes
class	NetPkt
	contains a network-layer packet with unacknowledged fragments More...

struct	Options

Public Types
using	UnackedFrags = std::map< lp::Sequence, UnackedFrag >

Public Member Functions
	LpReliability (const Options &options, GenericLinkService *linkService)

void	setOptions (const Options &options)
	set options for reliability More...

const GenericLinkService *	getLinkService () const

void	handleOutgoing (std::vector< lp::Packet > &frags, lp::Packet &&pkt, bool isInterest)
	observe outgoing fragment(s) of a network packet and store for potential retransmission More...

bool	processIncomingPacket (const lp::Packet &pkt)
	extract and parse all Acks and add Ack for contained Fragment (if any) to AckQueue More...

void	piggyback (lp::Packet &pkt, ssize_t mtu)
	called by GenericLinkService to attach Acks onto an outgoing LpPacket More...

void	startIdleAckTimer ()
	start the idle Ack timer More...

std::vector< lp::Sequence >	findLostLpPackets (UnackedFrags::iterator ackIt)
	find and mark as lost fragments where a configurable number of Acks (`m_options.seqNumLossThreshold`) have been received for greater TxSequence numbers More...

std::vector< lp::Sequence >	onLpPacketLost (lp::Sequence txSeq, bool isTimeout)
	resend (or give up on) a lost fragment More...

void	onLpPacketAcknowledged (UnackedFrags::iterator fragIt)
	remove the fragment with the given sequence number from the map of unacknowledged fragments, as well as its associated network packet (if any) More...

void	deleteUnackedFrag (UnackedFrags::iterator fragIt)
	delete a fragment from UnackedFrags and advance acknowledge window if necessary More...

Public Attributes
signal::Signal< LpReliability, Interest >	onDroppedInterest
	signals on Interest dropped by reliability system for exceeding allowed number of retx More...

NFD_PUBLIC_WITH_TESTS_ELSE_PRIVATE	__pad0__: class UnackedFrag

NFD_PUBLIC_WITH_TESTS_ELSE_PRIVATE	__pad1__: lp::Sequence assignTxSequence(lp::Packet& frag)

NFD_PUBLIC_WITH_TESTS_ELSE_PRIVATE	__pad2__: class UnackedFrag { public: explicit UnackedFrag(lp::Packet pkt)

lp::Packet	pkt

scheduler::ScopedEventId	rtoTimer

time::steady_clock::TimePoint	sendTime

size_t	retxCount

size_t	nGreaterSeqAcks
	number of Acks received for sequences greater than this fragment More...

shared_ptr< NetPkt >	netPkt

NFD_PUBLIC_WITH_TESTS_ELSE_PRIVATE	__pad3__: Options m_options

GenericLinkService *	m_linkService

UnackedFrags	m_unackedFrags

UnackedFrags::iterator	m_firstUnackedFrag
	An iterator that points to the first unacknowledged fragment in the current window. More...

std::queue< lp::Sequence >	m_ackQueue

std::map< lp::Sequence, time::steady_clock::TimePoint >	m_recentRecvSeqs

std::queue< lp::Sequence >	m_recentRecvSeqsQueue

lp::Sequence	m_lastTxSeqNo

scheduler::ScopedEventId	m_idleAckTimer

ndn::util::RttEstimator	m_rttEst

Static Public Attributes
static constexpr size_t	RESERVED_HEADER_SPACE
	TxSequence TLV-TYPE (3 octets) + TLV-LENGTH (1 octet) + lp::Sequence (8 octets) More...

Detailed Description

provides for reliable sending and receiving of link-layer packets

See also: https://redmine.named-data.net/projects/nfd/wiki/NDNLPv2

Definition at line 45 of file lp-reliability.hpp.

Member Typedef Documentation

◆ UnackedFrags

using nfd::face::LpReliability::UnackedFrags = std::map<lp::Sequence, UnackedFrag>

Definition at line 111 of file lp-reliability.hpp.

Constructor & Destructor Documentation

◆ LpReliability()

nfd::face::LpReliability::LpReliability	(	const Options &	options,
		GenericLinkService *	linkService
	)

Definition at line 36 of file lp-reliability.cpp.

References m_linkService.

Member Function Documentation

◆ setOptions()

void nfd::face::LpReliability::setOptions ( const Options & options )

set options for reliability

Definition at line 47 of file lp-reliability.cpp.

References ndn::detail::ScopedCancelHandle< HandleT >::cancel(), nfd::face::GenericLinkService, nfd::face::LpReliability::Options::idleAckTimerPeriod, nfd::face::LpReliability::Options::isEnabled, and m_idleAckTimer.

◆ getLinkService()

const GenericLinkService * nfd::face::LpReliability::getLinkService ( ) const

Returns: GenericLinkService that owns this instance

This is only used for logging, and may be nullptr.

Definition at line 59 of file lp-reliability.cpp.

References m_linkService.

◆ handleOutgoing()

void nfd::face::LpReliability::handleOutgoing	(	std::vector< lp::Packet > &	frags,
		lp::Packet &&	pkt,
		bool	isInterest
	)

observe outgoing fragment(s) of a network packet and store for potential retransmission

Parameters

frags	fragments of network packet
pkt	encapsulated network packet
isInterest	whether the network packet is an Interest

Definition at line 65 of file lp-reliability.cpp.

References ndn::util::RttEstimator::getEstimatedRto(), nfd::getScheduler(), m_firstUnackedFrag, m_rttEst, m_unackedFrags, nonstd::optional_lite::std11::move(), netPkt, NFD_LOG_FACE_TRACE, ndn::time::steady_clock::now(), onLpPacketLost(), pkt, and sendTime.

◆ processIncomingPacket()

bool nfd::face::LpReliability::processIncomingPacket ( const lp::Packet & pkt )

extract and parse all Acks and add Ack for contained Fragment (if any) to AckQueue

Parameters

pkt	incoming LpPacket

Returns: whether incoming LpPacket is new and not a duplicate

Definition at line 107 of file lp-reliability.cpp.

References ndn::util::RttEstimator::addMeasurement(), findLostLpPackets(), ndn::lp::Packet::get(), ndn::util::RttEstimator::getEstimatedRto(), ndn::lp::Packet::has(), ndn::lp::Packet::list(), m_ackQueue, m_recentRecvSeqs, m_recentRecvSeqsQueue, m_rttEst, m_unackedFrags, NFD_LOG_FACE_DEBUG, NFD_LOG_FACE_TRACE, ndn::time::steady_clock::now(), onLpPacketAcknowledged(), onLpPacketLost(), and startIdleAckTimer().

◆ piggyback()

void nfd::face::LpReliability::piggyback	(	lp::Packet &	pkt,
		ssize_t	mtu
	)

called by GenericLinkService to attach Acks onto an outgoing LpPacket

Parameters

pkt	outgoing LpPacket to attach Acks to
mtu	MTU of the Transport

Definition at line 193 of file lp-reliability.cpp.

References ndn::lp::tlv::Ack, ndn::lp::Packet::add(), ndn::lp::tlv::LpPacket, m_ackQueue, m_firstUnackedFrag, m_lastTxSeqNo, m_unackedFrags, ndn::MAX_NDN_PACKET_SIZE, nfd::face::MTU_UNLIMITED, NDN_THROW, NFD_LOG_FACE_TRACE, ndn::lp::Packet::set(), ndn::Block::size(), ndn::tlv::sizeOfVarNumber(), ndn::Block::type(), and ndn::lp::Packet::wireEncode().

◆ startIdleAckTimer()

void nfd::face::LpReliability::startIdleAckTimer ( )

start the idle Ack timer

This timer requests an IDLE packet to acknowledge pending fragments not already piggybacked. It is called regularly on a period configured in Options::idleAckTimerPeriod. This allows Acks to be returned to the sender, even if the link goes idle.

Definition at line 236 of file lp-reliability.cpp.

References nfd::getScheduler(), and m_idleAckTimer.

Referenced by processIncomingPacket().

◆ findLostLpPackets()

std::vector< lp::Sequence > nfd::face::LpReliability::findLostLpPackets ( UnackedFrags::iterator ackIt )

find and mark as lost fragments where a configurable number of Acks (m_options.seqNumLossThreshold) have been received for greater TxSequence numbers

Parameters

ackIt iterator pointing to acknowledged fragment

Returns: vector containing TxSequences of fragments marked lost by this mechanism

Definition at line 251 of file lp-reliability.cpp.

References m_firstUnackedFrag, m_unackedFrags, and NFD_LOG_FACE_TRACE.

Referenced by processIncomingPacket().

◆ onLpPacketLost()

std::vector< lp::Sequence > nfd::face::LpReliability::onLpPacketLost	(	lp::Sequence	txSeq,
		bool	isTimeout
	)

resend (or give up on) a lost fragment

Returns: vector of the TxSequences of fragments removed due to a network packet being removed

Definition at line 278 of file lp-reliability.cpp.

References deleteUnackedFrag(), ndn::util::RttEstimator::getEstimatedRto(), nfd::getScheduler(), ndn::tlv::Interest, m_firstUnackedFrag, m_linkService, m_rttEst, m_unackedFrags, netPkt, NFD_LOG_FACE_DEBUG, NFD_LOG_FACE_TRACE, and onDroppedInterest.

Referenced by handleOutgoing(), and processIncomingPacket().

◆ onLpPacketAcknowledged()

void nfd::face::LpReliability::onLpPacketAcknowledged ( UnackedFrags::iterator fragIt )

remove the fragment with the given sequence number from the map of unacknowledged fragments, as well as its associated network packet (if any)

Parameters

fragIt iterator to acknowledged fragment

If the given TxSequence marks the beginning of the send window, the window will be incremented. If the associated network packet has been fully transmitted, it will be removed.

Definition at line 364 of file lp-reliability.cpp.

References deleteUnackedFrag(), m_linkService, and netPkt.

Referenced by processIncomingPacket().

◆ deleteUnackedFrag()

void nfd::face::LpReliability::deleteUnackedFrag ( UnackedFrags::iterator fragIt )

delete a fragment from UnackedFrags and advance acknowledge window if necessary

Parameters

fragIt iterator to an UnackedFrag, must be dereferencable

Postcondition: fragIt is not in m_unackedFrags; if was equal to m_firstUnackedFrag, m_firstUnackedFrag is set to the UnackedFrag after fragIt with consideration of TxSequence number wraparound, or set to m_unackedFrags.end() if m_unackedFrags is empty

Definition at line 388 of file lp-reliability.cpp.

References m_firstUnackedFrag, m_unackedFrags, nonstd::optional_lite::std11::move(), nGreaterSeqAcks, ndn::time::steady_clock::now(), pkt, retxCount, and sendTime.

Referenced by onLpPacketAcknowledged(), and onLpPacketLost().

Member Data Documentation

◆ onDroppedInterest

signal::Signal<LpReliability, Interest> nfd::face::LpReliability::onDroppedInterest

signals on Interest dropped by reliability system for exceeding allowed number of retx

Definition at line 72 of file lp-reliability.hpp.

Referenced by onLpPacketLost().

◆ pad0

NFD_PUBLIC_WITH_TESTS_ELSE_PRIVATE nfd::face::LpReliability::__pad0__

Definition at line 109 of file lp-reliability.hpp.

◆ pad1

NFD_PUBLIC_WITH_TESTS_ELSE_PRIVATE nfd::face::LpReliability::__pad1__

Definition at line 120 of file lp-reliability.hpp.

◆ pad2

NFD_PUBLIC_WITH_TESTS_ELSE_PRIVATE nfd::face::LpReliability::__pad2__

Definition at line 172 of file lp-reliability.hpp.

◆ pkt

lp::Packet nfd::face::LpReliability::pkt

Definition at line 175 of file lp-reliability.hpp.

Referenced by deleteUnackedFrag(), and handleOutgoing().

◆ rtoTimer

scheduler::ScopedEventId nfd::face::LpReliability::rtoTimer

Definition at line 176 of file lp-reliability.hpp.

◆ sendTime

time::steady_clock::TimePoint nfd::face::LpReliability::sendTime

Definition at line 177 of file lp-reliability.hpp.

Referenced by deleteUnackedFrag(), and handleOutgoing().

◆ retxCount

size_t nfd::face::LpReliability::retxCount

Definition at line 178 of file lp-reliability.hpp.

Referenced by deleteUnackedFrag().

◆ nGreaterSeqAcks

size_t nfd::face::LpReliability::nGreaterSeqAcks

number of Acks received for sequences greater than this fragment

Definition at line 179 of file lp-reliability.hpp.

Referenced by deleteUnackedFrag().

◆ netPkt

shared_ptr<NetPkt> nfd::face::LpReliability::netPkt

Definition at line 180 of file lp-reliability.hpp.

Referenced by handleOutgoing(), onLpPacketAcknowledged(), and onLpPacketLost().

◆ RESERVED_HEADER_SPACE

constexpr size_t nfd::face::LpReliability::RESERVED_HEADER_SPACE

static

Initial value:

= tlv::sizeOfVarNumber(lp::tlv::TxSequence) +
                                                  tlv::sizeOfVarNumber(sizeof(lp::Sequence)) +
                                                  sizeof(lp::Sequence)

TxSequence TLV-TYPE (3 octets) + TLV-LENGTH (1 octet) + lp::Sequence (8 octets)

Definition at line 199 of file lp-reliability.hpp.

◆ pad3

NFD_PUBLIC_WITH_TESTS_ELSE_PRIVATE nfd::face::LpReliability::__pad3__

Definition at line 204 of file lp-reliability.hpp.

◆ m_linkService

GenericLinkService* nfd::face::LpReliability::m_linkService

Definition at line 205 of file lp-reliability.hpp.

Referenced by getLinkService(), LpReliability(), onLpPacketAcknowledged(), and onLpPacketLost().

◆ m_unackedFrags

UnackedFrags nfd::face::LpReliability::m_unackedFrags

Definition at line 206 of file lp-reliability.hpp.

Referenced by deleteUnackedFrag(), findLostLpPackets(), handleOutgoing(), onLpPacketLost(), piggyback(), and processIncomingPacket().

◆ m_firstUnackedFrag

UnackedFrags::iterator nfd::face::LpReliability::m_firstUnackedFrag

An iterator that points to the first unacknowledged fragment in the current window.

The window can wrap around so that the beginning of the window is at a TxSequence greater than other fragments in the window. When the window is moved past the last item in the iterator, the first fragment in the map will become the start of the window.

Definition at line 212 of file lp-reliability.hpp.

Referenced by deleteUnackedFrag(), findLostLpPackets(), handleOutgoing(), onLpPacketLost(), and piggyback().

◆ m_ackQueue

std::queue<lp::Sequence> nfd::face::LpReliability::m_ackQueue

Definition at line 213 of file lp-reliability.hpp.

Referenced by piggyback(), and processIncomingPacket().

◆ m_recentRecvSeqs

std::map<lp::Sequence, time::steady_clock::TimePoint> nfd::face::LpReliability::m_recentRecvSeqs

Definition at line 214 of file lp-reliability.hpp.

Referenced by processIncomingPacket().

◆ m_recentRecvSeqsQueue

std::queue<lp::Sequence> nfd::face::LpReliability::m_recentRecvSeqsQueue

Definition at line 215 of file lp-reliability.hpp.

Referenced by processIncomingPacket().

◆ m_lastTxSeqNo

lp::Sequence nfd::face::LpReliability::m_lastTxSeqNo

Definition at line 216 of file lp-reliability.hpp.

Referenced by piggyback().

◆ m_idleAckTimer

scheduler::ScopedEventId nfd::face::LpReliability::m_idleAckTimer

Definition at line 217 of file lp-reliability.hpp.

Referenced by setOptions(), and startIdleAckTimer().

◆ m_rttEst

ndn::util::RttEstimator nfd::face::LpReliability::m_rttEst

Definition at line 218 of file lp-reliability.hpp.

Referenced by handleOutgoing(), onLpPacketLost(), and processIncomingPacket().

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

ndnSIM/NFD/daemon/face/lp-reliability.hpp
ndnSIM/NFD/daemon/face/lp-reliability.cpp

Classes

Public Types

Public Member Functions

Public Attributes

Static Public Attributes

Detailed Description

Member Typedef Documentation

◆ UnackedFrags

Constructor & Destructor Documentation

◆ LpReliability()

Member Function Documentation

◆ setOptions()

◆ getLinkService()

◆ handleOutgoing()

◆ processIncomingPacket()

◆ piggyback()

◆ startIdleAckTimer()

◆ findLostLpPackets()

◆ onLpPacketLost()

◆ onLpPacketAcknowledged()

◆ deleteUnackedFrag()

Member Data Documentation

◆ onDroppedInterest

◆ __pad0__

◆ __pad1__

◆ __pad2__

◆ pkt

◆ rtoTimer

◆ sendTime

◆ retxCount

◆ nGreaterSeqAcks

◆ netPkt

◆ RESERVED_HEADER_SPACE

◆ __pad3__

◆ m_linkService

◆ m_unackedFrags

◆ m_firstUnackedFrag

◆ m_ackQueue

◆ m_recentRecvSeqs

◆ m_recentRecvSeqsQueue

◆ m_lastTxSeqNo

◆ m_idleAckTimer

◆ m_rttEst

◆ pad0

◆ pad1

◆ pad2

◆ pad3