Rx reordering buffer for TCP. More...

#include "tcp-rx-buffer.h"

Inheritance diagram for ns3::TcpRxBuffer:

Collaboration diagram for ns3::TcpRxBuffer:

Public Member Functions
	TcpRxBuffer (uint32_t n=0)
	Constructor.

	~TcpRxBuffer () override

bool	Add (Ptr< Packet > p, const TcpHeader &tcph)
	Insert a packet into the buffer and update the availBytes counter to reflect the number of bytes ready to send to the application.

uint32_t	Available () const
	Get the actual number of bytes available to be read.

Ptr< Packet >	Extract (uint32_t maxSize)
	Extract data from the head of the buffer as indicated by nextRxSeq.

bool	Finished ()
	Check if the buffer did receive all the data (and the connection is closed)

TcpOptionSack::SackList	GetSackList () const
	Get the sack list.

uint32_t	GetSackListSize () const
	Get the size of Sack list.

bool	GotFin () const
	Says if a FIN bit has been received.

void	IncNextRxSequence ()
	Increment the Next Sequence number.

uint32_t	MaxBufferSize () const
	Get the Maximum buffer size.

SequenceNumber32	MaxRxSequence () const
	Get the lowest sequence number that this TcpRxBuffer cannot accept.

SequenceNumber32	NextRxSequence () const
	Get Next Rx Sequence number.

void	SetFinSequence (const SequenceNumber32 &s)
	Set the FIN Sequence number (i.e., the one closing the connection)

void	SetMaxBufferSize (uint32_t s)
	Set the Maximum buffer size.

void	SetNextRxSequence (const SequenceNumber32 &s)
	Set the Next Sequence number.

uint32_t	Size () const
	Get the actual buffer occupancy.

Public Member Functions inherited from ns3::Object
	Object ()
	Constructor.

	~Object () override
	Destructor.

void	AggregateObject (Ptr< Object > other)
	Aggregate two Objects together.

void	Dispose ()
	Dispose of this Object.

AggregateIterator	GetAggregateIterator () const
	Get an iterator to the Objects aggregated to this one.

TypeId	GetInstanceTypeId () const override
	Get the most derived TypeId for this Object.

template<typename T >
Ptr< T >	GetObject () const
	Get a pointer to the requested aggregated Object.

template<>
Ptr< Object >	GetObject () const
	Specialization of () for objects of type ns3::Object.

template<typename T >
Ptr< T >	GetObject (TypeId tid) const
	Get a pointer to the requested aggregated Object by TypeId.

template<>
Ptr< Object >	GetObject (TypeId tid) const
	Specialization of (TypeId tid) for objects of type ns3::Object.

void	Initialize ()
	Invoke DoInitialize on all Objects aggregated to this one.

bool	IsInitialized () const
	Check if the object has been initialized.

void	UnidirectionalAggregateObject (Ptr< Object > other)
	Aggregate an Object to another Object.

Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter >
	SimpleRefCount ()
	Default constructor.

	SimpleRefCount (const SimpleRefCount &o)
	Copy constructor.

uint32_t	GetReferenceCount () const
	Get the reference count of the object.

SimpleRefCount &	operator= (const SimpleRefCount &o)
	Assignment operator.

void	Ref () const
	Increment the reference count.

void	Unref () const
	Decrement the reference count.

Public Member Functions inherited from ns3::ObjectBase
virtual	~ObjectBase ()
	Virtual destructor.

void	GetAttribute (std::string name, AttributeValue &value, bool permissive=false) const
	Get the value of an attribute, raising fatal errors if unsuccessful.

bool	GetAttributeFailSafe (std::string name, AttributeValue &value) const
	Get the value of an attribute without raising errors.

void	SetAttribute (std::string name, const AttributeValue &value)
	Set a single attribute, raising fatal errors if unsuccessful.

bool	SetAttributeFailSafe (std::string name, const AttributeValue &value)
	Set a single attribute without raising errors.

bool	TraceConnect (std::string name, std::string context, const CallbackBase &cb)
	Connect a TraceSource to a Callback with a context.

bool	TraceConnectWithoutContext (std::string name, const CallbackBase &cb)
	Connect a TraceSource to a Callback without a context.

bool	TraceDisconnect (std::string name, std::string context, const CallbackBase &cb)
	Disconnect from a TraceSource a Callback previously connected with a context.

bool	TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb)
	Disconnect from a TraceSource a Callback previously connected without a context.

Static Public Member Functions
static TypeId	GetTypeId ()
	Get the type ID.

Static Public Member Functions inherited from ns3::Object
static TypeId	GetTypeId ()
	Register this type.

Static Public Member Functions inherited from ns3::ObjectBase
static TypeId	GetTypeId ()
	Get the type ID.

Private Types
typedef std::map< SequenceNumber32, Ptr< Packet > >::iterator	BufIterator
	container for data stored in the buffer

Private Member Functions
void	ClearSackList (const SequenceNumber32 &seq)
	Remove old blocks from the sack list.

void	UpdateSackList (const SequenceNumber32 &head, const SequenceNumber32 &tail)
	Update the sack list, with the block seq starting at the beginning.

Private Attributes
uint32_t	m_availBytes
	Number of bytes available to read, i.e.

std::map< SequenceNumber32, Ptr< Packet > >	m_data
	Corresponding data (may be null)

SequenceNumber32	m_finSeq
	Seqnum of the FIN packet.

bool	m_gotFin
	Did I received FIN packet?

uint32_t	m_maxBuffer
	Upper bound of the number of data bytes in buffer (RCV.WND)

TracedValue< SequenceNumber32 >	m_nextRxSeq
	Seqnum of the first missing byte in data (RCV.NXT)

TcpOptionSack::SackList	m_sackList
	Sack list (updated constantly)

uint32_t	m_size
	Number of total data bytes in the buffer, not necessarily contiguous.

Additional Inherited Members
Protected Member Functions inherited from ns3::Object
	Object (const Object &o)
	Copy an Object.

virtual void	DoDispose ()
	Destructor implementation.

virtual void	DoInitialize ()
	Initialize() implementation.

virtual void	NotifyNewAggregate ()
	Notify all Objects aggregated to this one of a new Object being aggregated.

Protected Member Functions inherited from ns3::ObjectBase
void	ConstructSelf (const AttributeConstructionList &attributes)
	Complete construction of ObjectBase; invoked by derived classes.

virtual void	NotifyConstructionCompleted ()
	Notifier called once the ObjectBase is fully constructed.

Related Symbols inherited from ns3::ObjectBase
static TypeId	GetObjectIid ()
	Ensure the TypeId for ObjectBase gets fully configured to anchor the inheritance tree properly.

Detailed Description

Rx reordering buffer for TCP.

The class is responsible to safely store the segments, and then returning them in-order to the application, where "in-order" does not means "network-order", but "sender-order" : the bytes should be returned in the same order that the sender application used to push them down on wire.

The first useful sequence that this class is waiting is returned by the method NextRxSequence, and could be set at the beginning through MaxRxSequence.

The max. size of this buffer is managed through SetMaxBufferSize, and could be retrieved using MaxBufferSize. The current size instead is returned by Size, while the amount of in-order data that could be extracted is returned by the method Available.

To store data, use Add; for retrieving a certain amount of ordered data, use the method Extract.

SACK list

An interesting feature of this class is the ability to maintain an ordered SACK list, under the definition of RFC 2018. When a out-of-order segment reaches this buffer, an ACK will be sent out, and the SACK list is generated or updated. From RFC 2018:

‍If sent at all, SACK options SHOULD be included in all ACKs which do not ACK the highest sequence number in the data receiver's queue.

For more information about the SACK list, please check the documentation of the method GetSackList.

See also: GetSackList; UpdateSackList

Definition at line 64 of file tcp-rx-buffer.h.

Member Typedef Documentation

◆ BufIterator

typedef std::map<SequenceNumber32,Ptr<Packet>>::iterator ns3::TcpRxBuffer::BufIterator

private

container for data stored in the buffer

Definition at line 215 of file tcp-rx-buffer.h.

Constructor & Destructor Documentation

◆ TcpRxBuffer()

ns3::TcpRxBuffer::TcpRxBuffer ( uint32_t n = 0 )

Constructor.

Parameters

n	initial Sequence number to be received

Definition at line 42 of file tcp-rx-buffer.cc.

◆ ~TcpRxBuffer()

ns3::TcpRxBuffer::~TcpRxBuffer ( )

override

Definition at line 51 of file tcp-rx-buffer.cc.

Member Function Documentation

◆ Add()

bool ns3::TcpRxBuffer::Add	(	Ptr< Packet >	p,
		const TcpHeader &	tcph )

Insert a packet into the buffer and update the availBytes counter to reflect the number of bytes ready to send to the application.

This function handles overlap by trimming the head of the inputted packet and removing data from the buffer that overlaps the tail of the inputted packet

Parameters

p	packet
tcph	packet's TCP header

Returns: True when success, false otherwise.

Definition at line 136 of file tcp-rx-buffer.cc.

References ClearSackList(), ns3::TcpHeader::GetSequenceNumber(), m_availBytes, m_data, m_finSeq, m_gotFin, m_maxBuffer, m_nextRxSeq, m_size, NS_ASSERT, NS_LOG_FUNCTION, NS_LOG_LOGIC, pktSize, and UpdateSackList().

Referenced by TcpRxBufferTestCase::TestUpdateSACKList().

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◆ Available()

uint32_t ns3::TcpRxBuffer::Available ( ) const

Get the actual number of bytes available to be read.

Returns: size of available data (in bytes)

Definition at line 86 of file tcp-rx-buffer.cc.

References m_availBytes.

◆ ClearSackList()

void ns3::TcpRxBuffer::ClearSackList ( const SequenceNumber32 & seq )

private

Remove old blocks from the sack list.

Used to remove blocks already delivered to the application.

After this call, in the SACK list there will be only blocks with sequence numbers greater than seq; it is perfectly safe to call this function with an empty sack list.

Parameters

seq	Last sequence to remove

Definition at line 341 of file tcp-rx-buffer.cc.

References m_sackList, NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by Add().

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◆ Extract()

Ptr< Packet > ns3::TcpRxBuffer::Extract ( uint32_t maxSize )

Extract data from the head of the buffer as indicated by nextRxSeq.

The extracted data is going to be forwarded to the application.

Parameters

maxSize maximum number of bytes to extract

Returns: a packet

Definition at line 368 of file tcp-rx-buffer.cc.

References ns3::Create(), m_availBytes, m_data, m_nextRxSeq, m_size, NS_ASSERT, NS_LOG_FUNCTION, NS_LOG_LOGIC, and pktSize.

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◆ Finished()

bool ns3::TcpRxBuffer::Finished ( )

Check if the buffer did receive all the data (and the connection is closed)

Returns: true if all data have been received

Definition at line 130 of file tcp-rx-buffer.cc.

References m_finSeq, m_gotFin, and m_nextRxSeq.

◆ GetSackList()

TcpOptionSack::SackList ns3::TcpRxBuffer::GetSackList ( ) const

Get the sack list.

The sack list can be empty, and it is updated each time Add or Extract are called through the private method UpdateSackList.

Returns: a list of isolated blocks

Definition at line 362 of file tcp-rx-buffer.cc.

References m_sackList.

Referenced by TcpRxBufferTestCase::TestUpdateSACKList().

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◆ GetSackListSize()

uint32_t ns3::TcpRxBuffer::GetSackListSize ( ) const

Get the size of Sack list.

Returns: the size of the sack block list; can be empty

Definition at line 236 of file tcp-rx-buffer.cc.

References m_sackList, and NS_LOG_FUNCTION.

◆ GetTypeId()

TypeId ns3::TcpRxBuffer::GetTypeId ( )

static

Get the type ID.

Returns: the object TypeId

Definition at line 22 of file tcp-rx-buffer.cc.

References m_nextRxSeq, ns3::MakeTraceSourceAccessor(), and ns3::TypeId::SetParent().

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◆ GotFin()

bool ns3::TcpRxBuffer::GotFin ( ) const

inline

Says if a FIN bit has been received.

Returns: true if we received a FIN bit

Definition at line 173 of file tcp-rx-buffer.h.

References m_gotFin.

◆ IncNextRxSequence()

void ns3::TcpRxBuffer::IncNextRxSequence ( )

Increment the Next Sequence number.

Definition at line 92 of file tcp-rx-buffer.cc.

References m_nextRxSeq, m_size, NS_ASSERT, and NS_LOG_FUNCTION.

◆ MaxBufferSize()

uint32_t ns3::TcpRxBuffer::MaxBufferSize ( ) const

Get the Maximum buffer size.

Returns: the Maximum buffer size

Definition at line 68 of file tcp-rx-buffer.cc.

References m_maxBuffer.

◆ MaxRxSequence()

SequenceNumber32 ns3::TcpRxBuffer::MaxRxSequence ( ) const

Get the lowest sequence number that this TcpRxBuffer cannot accept.

Returns: the lowest sequence number that this TcpRxBuffer cannot accept

Definition at line 103 of file tcp-rx-buffer.cc.

References m_data, m_finSeq, m_gotFin, m_maxBuffer, and m_nextRxSeq.

◆ NextRxSequence()

SequenceNumber32 ns3::TcpRxBuffer::NextRxSequence ( ) const

Get Next Rx Sequence number.

Returns: Next Rx Sequence number

Definition at line 56 of file tcp-rx-buffer.cc.

References m_nextRxSeq.

Referenced by TcpRxBufferTestCase::TestUpdateSACKList().

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◆ SetFinSequence()

void ns3::TcpRxBuffer::SetFinSequence ( const SequenceNumber32 & s )

Set the FIN Sequence number (i.e., the one closing the connection)

Parameters

s	the Sequence number

Definition at line 117 of file tcp-rx-buffer.cc.

References m_finSeq, m_gotFin, m_nextRxSeq, and NS_LOG_FUNCTION.

◆ SetMaxBufferSize()

void ns3::TcpRxBuffer::SetMaxBufferSize ( uint32_t s )

Set the Maximum buffer size.

Parameters

s	the Maximum buffer size

Definition at line 74 of file tcp-rx-buffer.cc.

References m_maxBuffer.

◆ SetNextRxSequence()

void ns3::TcpRxBuffer::SetNextRxSequence ( const SequenceNumber32 & s )

Set the Next Sequence number.

Parameters

s	the Sequence number

Definition at line 62 of file tcp-rx-buffer.cc.

References m_nextRxSeq.

Referenced by TcpRxBufferTestCase::TestUpdateSACKList().

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◆ Size()

uint32_t ns3::TcpRxBuffer::Size ( ) const

Get the actual buffer occupancy.

Returns: buffer occupancy (in bytes)

Definition at line 80 of file tcp-rx-buffer.cc.

References m_size.

◆ UpdateSackList()

void ns3::TcpRxBuffer::UpdateSackList	(	const SequenceNumber32 &	head,
		const SequenceNumber32 &	tail )

private

Update the sack list, with the block seq starting at the beginning.

Note: the maximum size of the block list is 4. Caller is free to drop blocks at the end to accommodate header size; from RFC 2018:

‍The data receiver SHOULD include as many distinct SACK blocks as possible in the SACK option. Note that the maximum available option space may not be sufficient to report all blocks present in the receiver's queue.

In fact, the maximum amount of blocks is 4, and if we consider the timestamp (or other) options, it is even less. For more detail about this function, please see the source code and in-line comments.

Parameters

head	sequence number of the block at the beginning
tail	sequence number of the block at the end

Definition at line 244 of file tcp-rx-buffer.cc.

References m_nextRxSeq, m_sackList, NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by Add().

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Member Data Documentation

◆ m_availBytes

uint32_t ns3::TcpRxBuffer::m_availBytes

private

Number of bytes available to read, i.e.

contiguous block at head

Definition at line 222 of file tcp-rx-buffer.h.

Referenced by Add(), Available(), and Extract().

◆ m_data

std::map<SequenceNumber32, Ptr<Packet> > ns3::TcpRxBuffer::m_data

private

Corresponding data (may be null)

Definition at line 223 of file tcp-rx-buffer.h.

Referenced by Add(), Extract(), and MaxRxSequence().

◆ m_finSeq

SequenceNumber32 ns3::TcpRxBuffer::m_finSeq

private

Seqnum of the FIN packet.

Definition at line 218 of file tcp-rx-buffer.h.

Referenced by Add(), Finished(), MaxRxSequence(), and SetFinSequence().

◆ m_gotFin

bool ns3::TcpRxBuffer::m_gotFin

private

Did I received FIN packet?

Definition at line 219 of file tcp-rx-buffer.h.

Referenced by Add(), Finished(), GotFin(), MaxRxSequence(), and SetFinSequence().

◆ m_maxBuffer

uint32_t ns3::TcpRxBuffer::m_maxBuffer

private

Upper bound of the number of data bytes in buffer (RCV.WND)

Definition at line 221 of file tcp-rx-buffer.h.

Referenced by Add(), MaxBufferSize(), MaxRxSequence(), and SetMaxBufferSize().

◆ m_nextRxSeq

TracedValue<SequenceNumber32> ns3::TcpRxBuffer::m_nextRxSeq

private

Seqnum of the first missing byte in data (RCV.NXT)

Definition at line 217 of file tcp-rx-buffer.h.

Referenced by Add(), Extract(), Finished(), GetTypeId(), IncNextRxSequence(), MaxRxSequence(), NextRxSequence(), SetFinSequence(), SetNextRxSequence(), and UpdateSackList().

◆ m_sackList

TcpOptionSack::SackList ns3::TcpRxBuffer::m_sackList

private

Sack list (updated constantly)

Definition at line 212 of file tcp-rx-buffer.h.

Referenced by ClearSackList(), GetSackList(), GetSackListSize(), and UpdateSackList().

◆ m_size

uint32_t ns3::TcpRxBuffer::m_size

private

Number of total data bytes in the buffer, not necessarily contiguous.

Definition at line 220 of file tcp-rx-buffer.h.

Referenced by Add(), Extract(), IncNextRxSequence(), and Size().

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

src/internet/model/tcp-rx-buffer.h
src/internet/model/tcp-rx-buffer.cc

Public Member Functions

Static Public Member Functions

Private Types

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

SACK list

Member Typedef Documentation

◆ BufIterator

Constructor & Destructor Documentation

◆ TcpRxBuffer()

◆ ~TcpRxBuffer()

Member Function Documentation

◆ Add()

◆ Available()

◆ ClearSackList()

◆ Extract()

◆ Finished()

◆ GetSackList()

◆ GetSackListSize()

◆ GetTypeId()

◆ GotFin()

◆ IncNextRxSequence()

◆ MaxBufferSize()

◆ MaxRxSequence()

◆ NextRxSequence()

◆ SetFinSequence()

◆ SetMaxBufferSize()

◆ SetNextRxSequence()

◆ Size()

◆ UpdateSackList()

Member Data Documentation

◆ m_availBytes

◆ m_data

◆ m_finSeq

◆ m_gotFin

◆ m_maxBuffer

◆ m_nextRxSeq

◆ m_sackList

◆ m_size