Tcp sender buffer. More...

#include "tcp-tx-buffer.h"

Inheritance diagram for ns3::TcpTxBuffer:

Collaboration diagram for ns3::TcpTxBuffer:

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

	~TcpTxBuffer () override

bool	Add (Ptr< Packet > p)
	Append a data packet to the end of the buffer.

void	AddRenoSack ()
	Emulate SACKs for SACKless connection: account for a new dupack.

uint32_t	Available () const
	Returns the available capacity of this buffer.

uint32_t	BytesInFlight () const
	Return total bytes in flight.

TcpTxItem *	CopyFromSequence (uint32_t numBytes, const SequenceNumber32 &seq)
	Copy data from the range [seq, seq+numBytes) into a packet.

void	DeleteRetransmittedFlagFromHead ()
	DeleteRetransmittedFlagFromHead.

void	DiscardUpTo (const SequenceNumber32 &seq, const Callback< void, TcpTxItem * > &beforeDelCb=m_nullCb)
	Discard data up to but not including this sequence number.

uint32_t	GetLost () const
	Get the number of segments that we believe are lost in the network.

uint32_t	GetRetransmitsCount () const
	Return the number of segments in the sent list that have been transmitted more than once, without acknowledgment.

uint32_t	GetSacked () const
	Get the number of segments that have been explicitly sacked by the receiver.

SequenceNumber32	HeadSequence () const
	Get the sequence number of the buffer head.

bool	IsHeadRetransmitted () const
	Check if the head is retransmitted.

bool	IsLost (const SequenceNumber32 &seq) const
	Check if a segment is lost.

bool	IsRetransmittedDataAcked (const SequenceNumber32 &ack) const
	Checks whether the ack corresponds to retransmitted data.

bool	IsSackEnabled () const
	check whether SACK is used on the corresponding TCP socket

void	MarkHeadAsLost ()
	Mark the head of the sent list as lost.

uint32_t	MaxBufferSize () const
	Get the maximum buffer size.

bool	NextSeg (SequenceNumber32 seq, SequenceNumber32 seqHigh, bool isRecovery) const
	Get the next sequence number to transmit, according to RFC 6675.

void	ResetLastSegmentSent ()
	Take the last segment sent and put it back into the un-sent list (at the beginning)

void	ResetRenoSack ()
	Reset the SACKs.

void	ResetSentList ()
	Reset the sent list.

void	SetDupAckThresh (uint32_t dupAckThresh)
	Set the DupAckThresh.

void	SetHeadSequence (const SequenceNumber32 &seq)
	Set the head sequence of the buffer.

void	SetMaxBufferSize (uint32_t n)
	Set the maximum buffer size.

void	SetRWndCallback (Callback< uint32_t > rWndCallback)
	Set callback to obtain receiver window value.

void	SetSackEnabled (bool enabled)
	tell tx-buffer whether SACK is used on this TCP socket

void	SetSegmentSize (uint32_t segmentSize)
	Set the segment size.

void	SetSentListLost (bool resetSack=false)
	Set the entire sent list as lost (typically after an RTO)

uint32_t	Size () const
	Returns total number of bytes in this buffer.

uint32_t	SizeFromSequence (const SequenceNumber32 &seq) const
	Returns the number of bytes from the buffer in the range [seq, tailSequence)

SequenceNumber32	TailSequence () const
	Get the sequence number of the buffer tail (plus one)

uint32_t	Update (const TcpOptionSack::SackList &list, const Callback< void, TcpTxItem * > &sackedCb=m_nullCb)
	Update the scoreboard.

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::list< TcpTxItem * >	PacketList
	container for data stored in the buffer

Private Member Functions
uint32_t	BytesInFlightRFC () const
	Calculate the number of bytes in flight per RFC 6675.

void	ConsistencyCheck () const
	Check if the values of sacked, lost, retrans, are in sync with the sent list.

std::pair< TcpTxBuffer::PacketList::const_iterator, SequenceNumber32 >	FindHighestSacked () const
	Find the highest SACK byte.

TcpTxItem *	GetNewSegment (uint32_t numBytes)
	Get a block of data not transmitted yet and move it into SentList.

TcpTxItem *	GetPacketFromList (PacketList &list, const SequenceNumber32 &startingSeq, uint32_t numBytes, const SequenceNumber32 &requestedSeq, bool *listEdited=nullptr) const
	Get a block (which is returned as Packet) from a list.

TcpTxItem *	GetTransmittedSegment (uint32_t numBytes, const SequenceNumber32 &seq)
	Get a block of data previously transmitted.

bool	IsLostRFC (const SequenceNumber32 &seq, const PacketList::const_iterator &segment) const
	Decide if a segment is lost based on RFC 6675 algorithm.

void	MergeItems (TcpTxItem t1, TcpTxItem t2) const
	Merge two TcpTxItem.

void	RemoveFromCounts (TcpTxItem *item, uint32_t size)
	Remove the size specified from the lostOut, retrans, sacked count.

void	SplitItems (TcpTxItem t1, TcpTxItem t2, uint32_t size) const
	Split one TcpTxItem.

void	UpdateLostCount ()
	Update the lost count.

Private Attributes
PacketList	m_appList
	Buffer for application data.

uint32_t	m_dupAckThresh {0}
	Duplicate Ack threshold from TcpSocketBase.

TracedValue< SequenceNumber32 >	m_firstByteSeq
	Sequence number of the first byte in data (SND.UNA)

std::pair< PacketList::const_iterator, SequenceNumber32 >	m_highestSack
	Highest SACK byte.

uint32_t	m_lostOut {0}
	Number of lost bytes.

uint32_t	m_maxBuffer
	Max number of data bytes in buffer (SND.WND)

bool	m_renoSack {false}
	Indicates if AddRenoSack was called.

uint32_t	m_retrans {0}
	Number of retransmitted bytes.

Callback< uint32_t >	m_rWndCallback
	Callback to obtain RCV.WND value.

uint32_t	m_sackedOut {0}
	Number of sacked bytes.

bool	m_sackEnabled {true}
	Indicates if SACK is enabled on this connection.

bool	m_sackSeen {false}
	Indicates if a SACK was received.

uint32_t	m_segmentSize {0}
	Segment size from TcpSocketBase.

PacketList	m_sentList
	Buffer for sent (but not acked) data.

uint32_t	m_sentSize
	Size of sent (and not discarded) segments.

uint32_t	m_size
	Size of all data in this buffer.

Static Private Attributes
static Callback< void, TcpTxItem * >	m_nullCb = MakeNullCallback<void, TcpTxItem*>()
	Null callback for an item.

Friends
std::ostream &	operator<< (std::ostream &os, const TcpTxBuffer &tcpTxBuf)
	Output operator.

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

Tcp sender buffer.

The class keeps track of all data that the application wishes to transmit to the other end. When the data is acknowledged, it is removed from the buffer. The buffer has a maximum size, and data is not saved if the amount exceeds the limit. Packets can be added to the class through the method Add(). An important thing to remember is that all the data managed is strictly sequential. It can be divided into blocks, but all the data follow a strict ordering. That order is managed through SequenceNumber.

In other words, this buffer contains numbered bytes (e.g., 1,2,3), and the class is allowed to return only ordered (using "<" as operator) subsets (e.g. 1,2 or 2,3 or 1,2,3).

The data structure underlying this is composed by two distinct packet lists. The first (SentList) is initially empty, and it contains the packets returned by the method CopyFromSequence. The second (AppList) is initially empty, and it contains the packets coming from the applications, but that are not transmitted yet as segments. To discover how the chunks are managed and retrieved from these lists, check CopyFromSequence documentation.

The head of the data is represented by m_firstByteSeq, and it is returned by HeadSequence(). The last byte is returned by TailSequence(). In this class, we also store the size (in bytes) of the packets inside the SentList in the variable m_sentSize.

SACK management

The SACK information is usually saved in a data structure referred as scoreboard. In this implementation, the scoreboard is developed on top of the existing classes. In particular, instead of keeping raw pointers to packets in TcpTxBuffer we added the capability to store some flags associated with every segment sent. This is done through the use of the class TcpTxItem: instead of storing a list of packets, we store a list of TcpTxItem. Each item has different flags (check the corresponding documentation) and maintaining the scoreboard is a matter of travelling the list and set the SACK flag on the corresponding segment sent.

Item properties

An item (that represent a segment in flight) is not considered in flight anymore when it is marked lost or sacked. A sacked item represents an item which is received by the other end, but it is still impossible to delete from the list because other pieces are missing at the other end. A lost item never reached the other end, and retransmission is probably needed. Other properties are retransmitted, that indicates if an item was retransmitted, and the sequence number of the first byte of the packet. When a segment is sent for the first time, only the sequence number is set, and all the remaining properties are set to false. If an item is explicitly sacked by the receiver, we mark it as such. Each time we receive updated sack information from the other end, we perform a check to evaluate the segments that can be lost (

See also: UpdateLostCount), and we set the flags accordingly.

Management of bytes in flight

Since this class manages all the output segments and the scoreboard, we can do calculations about the number of bytes in flights. Earlier versions of this class used algorithms copied from RFC 6675. They were inefficient because they required a complete walk into the list of sent segments each time a simple question, such as "Is this sequence lost?" or "How many bytes are in flight?". Therefore, the class has been updated keeping in consideration the RFCs (including RFC 4898) and the Linux operating system. As a reference, we kept the older methods for calculating the bytes in flight and if a segment is lost, renaming them as "RFC" version of the methods. To have a look how the calculations are made, please see BytesInFlight method.

Lost segments

After the sender receives a new SACK block, it updates the amount of segment that it considers as lost, following the specifications made in RFC 6675 (for more detail please see the method UpdateLostCount). In case of SACKless connection, the TcpSocketImplementation should provide hints through the MarkHeadAsLost and AddRenoSack methods.

See also: BytesInFlight; Size; SizeFromSequence; CopyFromSequence

Definition at line 112 of file tcp-tx-buffer.h.

Member Typedef Documentation

◆ PacketList

typedef std::list<TcpTxItem*> ns3::TcpTxBuffer::PacketList

private

container for data stored in the buffer

Definition at line 403 of file tcp-tx-buffer.h.

Constructor & Destructor Documentation

◆ TcpTxBuffer()

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

Constructor.

Parameters

n	initial Sequence number to be transmitted

Definition at line 49 of file tcp-tx-buffer.cc.

References m_rWndCallback, and ns3::MakeNullCallback().

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◆ ~TcpTxBuffer()

ns3::TcpTxBuffer::~TcpTxBuffer ( )

override

Definition at line 58 of file tcp-tx-buffer.cc.

References ns3::Packet::GetSize(), m_appList, ns3::TcpTxItem::m_packet, m_sentList, m_sentSize, and m_size.

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Member Function Documentation

◆ Add()

bool ns3::TcpTxBuffer::Add ( Ptr< Packet > p )

Append a data packet to the end of the buffer.

Parameters

p	The packet to be appended to the Tx buffer

Returns: Boolean to indicate success

Definition at line 171 of file tcp-tx-buffer.cc.

References Available(), m_appList, m_firstByteSeq, m_size, NS_LOG_FUNCTION, and NS_LOG_LOGIC.

Referenced by TcpTxBufferTestCase::TestMergeItemsWhenGetTransmittedSegment(), and TcpRateLinuxWithBufferTest::TestWithSackBlocks().

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◆ AddRenoSack()

void ns3::TcpTxBuffer::AddRenoSack ( )

Emulate SACKs for SACKless connection: account for a new dupack.

The method walk the list of the sent segment until it finds a segment that was not accounted in the sackedOut count. The head will never be included. To reset the information added with this function (e.g., after an RTO) please use ResetRenoSack.

The method DiscardUpTo, when invoked, will make sure to properly clean any flag on the discarded item. As example, if the implementation discard an item that is marked as sacked, the sackedOut count is decreased accordingly.

Definition at line 1370 of file tcp-tx-buffer.cc.

References ConsistencyCheck(), m_highestSack, m_renoSack, m_sackedOut, m_sackEnabled, m_sackSeen, m_sentList, NS_ASSERT, NS_LOG_FUNCTION, and NS_LOG_INFO.

Referenced by DiscardUpTo().

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◆ Available()

uint32_t ns3::TcpTxBuffer::Available ( ) const

Returns the available capacity of this buffer.

Returns: available capacity in this Tx window

Definition at line 118 of file tcp-tx-buffer.cc.

References m_maxBuffer, and m_size.

Referenced by Add().

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◆ BytesInFlight()

uint32_t ns3::TcpTxBuffer::BytesInFlight ( ) const

Return total bytes in flight.

Counting packets in flight is pretty simple:

sentsize is SND.NXT-SND.UNA, retrans is the number of retransmitted segments. leftOut is the number of segment that left the network without being ACKed:

To see how we define the lost packets, look at the method UpdateLostCount.

Returns: total bytes in flight

Definition at line 1057 of file tcp-tx-buffer.cc.

References m_lostOut, m_retrans, m_sackedOut, m_sentSize, NS_ASSERT_MSG, and NS_LOG_INFO.

Referenced by TcpRateLinuxWithBufferTest::TestWithSackBlocks().

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◆ BytesInFlightRFC()

uint32_t ns3::TcpTxBuffer::BytesInFlightRFC ( ) const

private

Calculate the number of bytes in flight per RFC 6675.

Returns: the number of bytes in flight

Definition at line 1078 of file tcp-tx-buffer.cc.

References ns3::Packet::GetSize(), IsLostRFC(), m_firstByteSeq, m_lostOut, ns3::TcpTxItem::m_packet, m_retrans, ns3::TcpTxItem::m_retrans, ns3::TcpTxItem::m_sacked, m_sackedOut, m_sentList, m_sentSize, and NS_ASSERT_MSG.

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◆ ConsistencyCheck()

void ns3::TcpTxBuffer::ConsistencyCheck ( ) const

private

Check if the values of sacked, lost, retrans, are in sync with the sent list.

Definition at line 1413 of file tcp-tx-buffer.cc.

References m_lostOut, m_retrans, m_sackedOut, m_sentList, and NS_ASSERT_MSG.

Referenced by AddRenoSack(), CopyFromSequence(), DeleteRetransmittedFlagFromHead(), DiscardUpTo(), MarkHeadAsLost(), ResetLastSegmentSent(), SetSentListLost(), Update(), and UpdateLostCount().

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◆ CopyFromSequence()

TcpTxItem * ns3::TcpTxBuffer::CopyFromSequence	(	uint32_t	numBytes,
		const SequenceNumber32 &	seq )

Copy data from the range [seq, seq+numBytes) into a packet.

In the following, we refer to the block [seq, seq+numBytes) simply as "block". We check the boundary of the block, and divide the possibilities in three cases:

the block have already been transmitted (managed in GetTransmittedSegment)
the block have not been transmitted yet (managed in GetNewSegment)

The last case is when the block is partially transmitted and partially not transmitted. We trick this case by requesting the portion not transmitted from GetNewSegment, and then calling GetTransmittedSegment with the full block range.

Parameters

numBytes	number of bytes to copy
seq	start sequence number to extract

Returns: a pointer to the TcpTxItem that corresponds to what requested. Please do not delete the pointer, nor modify Packet data or sequence numbers.

Definition at line 212 of file tcp-tx-buffer.cc.

References ConsistencyCheck(), CopyFromSequence(), ns3::TracedValue< T >::Get(), GetNewSegment(), GetTransmittedSegment(), ns3::SequenceNumber< NUMERIC_TYPE, SIGNED_TYPE >::GetValue(), m_firstByteSeq, ns3::TcpTxItem::m_lastSent, ns3::TcpTxItem::m_retrans, ns3::TcpTxItem::m_sacked, m_sentSize, ns3::TcpTxItem::m_startSeq, ns3::Simulator::Now(), NS_ABORT_MSG_IF, NS_ABORT_MSG_UNLESS, NS_ASSERT, NS_ASSERT_MSG, NS_LOG_DEBUG, NS_LOG_FUNCTION, and SizeFromSequence().

Referenced by CopyFromSequence(), DiscardUpTo(), TcpTxBufferTestCase::TestMergeItemsWhenGetTransmittedSegment(), and TcpRateLinuxWithBufferTest::TestWithSackBlocks().

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◆ DeleteRetransmittedFlagFromHead()

void ns3::TcpTxBuffer::DeleteRetransmittedFlagFromHead ( )

DeleteRetransmittedFlagFromHead.

Definition at line 1323 of file tcp-tx-buffer.cc.

References ConsistencyCheck(), m_retrans, m_sentList, m_sentSize, and NS_LOG_FUNCTION.

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◆ DiscardUpTo()

void ns3::TcpTxBuffer::DiscardUpTo	(	const SequenceNumber32 &	seq,
		const Callback< void, TcpTxItem * > &	beforeDelCb = m_nullCb )

Discard data up to but not including this sequence number.

Parameters

seq	The first sequence number to maintain after discarding all the previous sequences.
beforeDelCb	Callback invoked, if it is not null, before the deletion of an Item (because it was, probably, ACKed)

Definition at line 656 of file tcp-tx-buffer.cc.

References AddRenoSack(), ConsistencyCheck(), CopyFromSequence(), ns3::Packet::CreateFragment(), ns3::TracedValue< T >::Get(), ns3::TcpTxItem::GetPacketCopy(), ns3::Packet::GetSize(), ns3::Callback< R, UArgs >::IsNull(), m_firstByteSeq, m_highestSack, ns3::TcpTxItem::m_lost, m_lostOut, ns3::TcpTxItem::m_packet, m_retrans, ns3::TcpTxItem::m_sacked, m_sackedOut, m_sackSeen, m_sentList, m_sentSize, m_size, ns3::TcpTxItem::m_startSeq, MarkHeadAsLost(), NS_ASSERT, NS_ASSERT_MSG, NS_LOG_DEBUG, NS_LOG_FUNCTION, NS_LOG_INFO, NS_LOG_LOGIC, pktSize, and RemoveFromCounts().

Referenced by TcpRateLinuxWithBufferTest::TestWithSackBlocks().

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◆ FindHighestSacked()

std::pair< TcpTxBuffer::PacketList::const_iterator, SequenceNumber32 > ns3::TcpTxBuffer::FindHighestSacked ( ) const

private

Find the highest SACK byte.

Returns: a pair with the highest byte and an iterator inside m_sentList

Definition at line 348 of file tcp-tx-buffer.cc.

References ns3::Packet::GetSize(), m_firstByteSeq, ns3::TcpTxItem::m_packet, ns3::TcpTxItem::m_sacked, m_sentList, and NS_LOG_FUNCTION.

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◆ GetLost()

uint32_t ns3::TcpTxBuffer::GetLost ( ) const

Get the number of segments that we believe are lost in the network.

It is calculated in UpdateLostCount.

Returns: the number of lost segment

Definition at line 142 of file tcp-tx-buffer.cc.

References m_lostOut.

◆ GetNewSegment()

TcpTxItem * ns3::TcpTxBuffer::GetNewSegment ( uint32_t numBytes )

private

Get a block of data not transmitted yet and move it into SentList.

If the block is not yet transmitted, hopefully, seq is exactly the sequence number of the first byte of the first packet inside AppList. We extract the block from AppList and move it into the SentList, before returning the block itself. We manage possible fragmentation (or merges) inside AppList through GetPacketFromList.

See also: GetPacketFromList

Parameters

numBytes number of bytes to copy

Returns: the item that contains the right packet

Definition at line 271 of file tcp-tx-buffer.cc.

References GetPacketFromList(), ns3::Packet::GetSize(), m_appList, m_firstByteSeq, ns3::TcpTxItem::m_packet, m_sentList, m_sentSize, ns3::TcpTxItem::m_startSeq, NS_ASSERT, NS_LOG_FUNCTION, and NS_LOG_INFO.

Referenced by CopyFromSequence().

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◆ GetPacketFromList()

TcpTxItem * ns3::TcpTxBuffer::GetPacketFromList	(	PacketList &	list,
		const SequenceNumber32 &	startingSeq,
		uint32_t	numBytes,
		const SequenceNumber32 &	requestedSeq,
		bool *	listEdited = nullptr ) const

private

Get a block (which is returned as Packet) from a list.

This function extract a block [requestedSeq,numBytes) from the list, which starts at startingSeq.

The cases we need to manage are two, and they are depicted in the following image:

                     |------|     |----|     |----|
              list = |      | --> |    | --> |    |
                     |------|     |----|     |----|

                     ^      ^
                     | ^ ^  |         (1)
                   seq | |  seq + numBytes
                       | |
                       | |
                    seq   seq + numBytes     (2)

The case 1 is easy to manage: the requested block is exactly a packet already stored. If one value (seq or seq + numBytes) does not align to a packet boundary, or when both values does not align (case 2), it is a bit more complex.

Basically, we have two possible operations:

fragment : split an existing packet in two
merge : merge two existing packets in one

and we reduce case (2) to case (1) through sequentially applying fragment or merge. For instance:

    |------|
    |      |
    |------|

    ^ ^  ^ ^
    | |  | |
start |  | |
      |  | end
     seq |
         seq + numBytes

To reduce to case (1), we need to perform two fragment operations:

fragment (start, seq)
fragment (seq + numBytes, end)

After these operations, the requested block is exactly the resulting packet. Merge operation is required when the requested block span over two (or more) existing packets.

While this could be extremely slow in the worst possible scenario (one big packet which is split in small packets for transmission, and merged for re-transmission) that scenario is unlikely during a TCP transmission (since MSS can change, but it is stable, and retransmissions do not happen for each segment).

Parameters

list	List to extract block from
startingSeq	Starting sequence of the list
numBytes	Bytes to extract, starting from requestedSeq
requestedSeq	Requested sequence
listEdited	output parameter which indicates if the list has been edited

Returns: the item that contains the right packet

Definition at line 390 of file tcp-tx-buffer.cc.

References GetPacketFromList(), ns3::GetSize(), m_firstByteSeq, ns3::TcpTxItem::m_packet, m_sentList, ns3::TcpTxItem::m_startSeq, MergeItems(), NS_ASSERT, NS_ASSERT_MSG, NS_FATAL_ERROR, NS_LOG_FUNCTION, NS_LOG_INFO, NS_LOG_WARN, and SplitItems().

Referenced by GetNewSegment(), GetPacketFromList(), and GetTransmittedSegment().

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◆ GetRetransmitsCount()

uint32_t ns3::TcpTxBuffer::GetRetransmitsCount ( ) const

Return the number of segments in the sent list that have been transmitted more than once, without acknowledgment.

This method is to support the retransmits count for determining PipeSize in NewReno-style TCP.

Returns: number of segments that have been transmitted more than once, without acknowledgment

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

References m_retrans.

◆ GetSacked()

uint32_t ns3::TcpTxBuffer::GetSacked ( ) const

Get the number of segments that have been explicitly sacked by the receiver.

Returns: the number of sacked segment.

Definition at line 148 of file tcp-tx-buffer.cc.

References m_sackedOut.

◆ GetTransmittedSegment()

TcpTxItem * ns3::TcpTxBuffer::GetTransmittedSegment	(	uint32_t	numBytes,
		const SequenceNumber32 &	seq )

private

Get a block of data previously transmitted.

This is clearly a retransmission, and if everything is going well, the block requested is matching perfectly with another one requested in the past. If not, fragmentation or merge are required. We manage both inside GetPacketFromList.

See also: GetPacketFromList

Parameters

numBytes	number of bytes to copy
seq	sequence requested

Returns: the item that contains the right packet

Definition at line 295 of file tcp-tx-buffer.cc.

References GetPacketFromList(), ns3::Packet::GetSize(), m_firstByteSeq, ns3::TcpTxItem::m_packet, m_retrans, ns3::TcpTxItem::m_retrans, m_sentList, m_sentSize, NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by CopyFromSequence().

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◆ GetTypeId()

TypeId ns3::TcpTxBuffer::GetTypeId ( )

static

Get the type ID.

Returns: the object TypeId

Definition at line 29 of file tcp-tx-buffer.cc.

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

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◆ HeadSequence()

SequenceNumber32 ns3::TcpTxBuffer::HeadSequence ( ) const

Get the sequence number of the buffer head.

Returns: the first byte's sequence number

Definition at line 76 of file tcp-tx-buffer.cc.

References m_firstByteSeq.

◆ IsHeadRetransmitted()

bool ns3::TcpTxBuffer::IsHeadRetransmitted ( ) const

Check if the head is retransmitted.

Returns: true if the head is retransmitted, false in all other cases (including no segment sent)

Definition at line 1310 of file tcp-tx-buffer.cc.

References m_sentList, m_sentSize, and NS_LOG_FUNCTION.

◆ IsLost()

bool ns3::TcpTxBuffer::IsLost ( const SequenceNumber32 & seq ) const

Check if a segment is lost.

It does a check on the flags to determine if the segment has to be considered as lost for an external class

Parameters

seq	sequence to check

Returns: true if the sequence is supposed to be lost, false otherwise

Definition at line 917 of file tcp-tx-buffer.cc.

References m_highestSack, m_sentList, NS_LOG_FUNCTION, and NS_LOG_INFO.

◆ IsLostRFC()

bool ns3::TcpTxBuffer::IsLostRFC	(	const SequenceNumber32 &	seq,
		const PacketList::const_iterator &	segment ) const

private

Decide if a segment is lost based on RFC 6675 algorithm.

Parameters

seq	Sequence
segment	Iterator to the sequence

Returns: true if seq is lost per RFC 6675, false otherwise

Definition at line 1139 of file tcp-tx-buffer.cc.

References m_dupAckThresh, m_highestSack, ns3::TcpTxItem::m_lost, ns3::TcpTxItem::m_packet, ns3::TcpTxItem::m_retrans, ns3::TcpTxItem::m_sacked, m_segmentSize, m_sentList, NS_LOG_FUNCTION, and NS_LOG_INFO.

Referenced by BytesInFlightRFC().

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◆ IsRetransmittedDataAcked()

bool ns3::TcpTxBuffer::IsRetransmittedDataAcked ( const SequenceNumber32 & ack ) const

Checks whether the ack corresponds to retransmitted data.

Parameters

ack	ACK number received

Returns: true if retransmitted data was acked

Definition at line 640 of file tcp-tx-buffer.cc.

References ns3::TcpTxItem::m_packet, ns3::TcpTxItem::m_retrans, ns3::TcpTxItem::m_sacked, m_sentList, ns3::TcpTxItem::m_startSeq, and NS_LOG_FUNCTION.

◆ IsSackEnabled()

bool ns3::TcpTxBuffer::IsSackEnabled ( ) const

check whether SACK is used on the corresponding TCP socket

Returns: true if SACK is used

Definition at line 106 of file tcp-tx-buffer.cc.

References m_sackEnabled.

◆ MarkHeadAsLost()

void ns3::TcpTxBuffer::MarkHeadAsLost ( )

Mark the head of the sent list as lost.

Definition at line 1341 of file tcp-tx-buffer.cc.

References ConsistencyCheck(), m_lostOut, m_retrans, m_sackedOut, and m_sentList.

Referenced by DiscardUpTo(), and TcpTxBufferTestCase::TestMergeItemsWhenGetTransmittedSegment().

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◆ MaxBufferSize()

uint32_t ns3::TcpTxBuffer::MaxBufferSize ( ) const

Get the maximum buffer size.

Returns: the Tx window size (in bytes)

Definition at line 94 of file tcp-tx-buffer.cc.

References m_maxBuffer.

◆ MergeItems()

void ns3::TcpTxBuffer::MergeItems	(	TcpTxItem *	t1,
		TcpTxItem *	t2 ) const

private

Merge two TcpTxItem.

Merge t2 in t1. It consists in copying the lastSent field if t2 is more recent than t1. Retransmitted field is copied only if it set in t2 but not in t1. Sacked is copied only if it is true in both items.

Parameters

t1	first item
t2	second item

Definition at line 577 of file tcp-tx-buffer.cc.

References ns3::Packet::AddAtEnd(), ns3::Packet::GetSize(), ns3::TcpTxItem::m_lastSent, ns3::TcpTxItem::m_lost, ns3::TcpTxItem::m_packet, m_retrans, ns3::TcpTxItem::m_retrans, ns3::TcpTxItem::m_sacked, NS_ASSERT, NS_ASSERT_MSG, NS_LOG_FUNCTION, and NS_LOG_INFO.

Referenced by GetPacketFromList().

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◆ NextSeg()

bool ns3::TcpTxBuffer::NextSeg	(	SequenceNumber32 *	seq,
		SequenceNumber32 *	seqHigh,
		bool	isRecovery ) const

Get the next sequence number to transmit, according to RFC 6675.

Parameters

seq	Next sequence number to transmit, based on the scoreboard information
seqHigh	Maximum sequence number to transmit, based on SMSS and/or receiver window
isRecovery	true if the socket congestion state is in recovery mode

Returns: true is seq is updated, false otherwise

Definition at line 951 of file tcp-tx-buffer.cc.

References ns3::Packet::GetSize(), ns3::SequenceNumber< NUMERIC_TYPE, SIGNED_TYPE >::GetValue(), m_firstByteSeq, m_highestSack, ns3::TcpTxItem::m_lost, ns3::TcpTxItem::m_packet, ns3::TcpTxItem::m_retrans, m_rWndCallback, ns3::TcpTxItem::m_sacked, m_sackSeen, m_segmentSize, m_sentList, m_sentSize, ns3::TcpTxItem::m_startSeq, NS_LOG_FUNCTION, NS_LOG_INFO, and SizeFromSequence().

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◆ RemoveFromCounts()

void ns3::TcpTxBuffer::RemoveFromCounts	(	TcpTxItem *	item,
		uint32_t	size )

private

Remove the size specified from the lostOut, retrans, sacked count.

Used only in DiscardUpTo

Parameters

item	Item that will be discarded
size	size to remove (can be different from pktSize because of fragmentation)

Definition at line 618 of file tcp-tx-buffer.cc.

References ns3::TcpTxItem::m_lost, m_lostOut, m_retrans, ns3::TcpTxItem::m_retrans, ns3::TcpTxItem::m_sacked, m_sackedOut, NS_ASSERT, NS_ASSERT_MSG, and NS_LOG_FUNCTION.

Referenced by DiscardUpTo().

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◆ ResetLastSegmentSent()

void ns3::TcpTxBuffer::ResetLastSegmentSent ( )

Take the last segment sent and put it back into the un-sent list (at the beginning)

Definition at line 1243 of file tcp-tx-buffer.cc.

References ConsistencyCheck(), ns3::Packet::GetSize(), m_appList, ns3::TcpTxItem::m_packet, m_retrans, ns3::TcpTxItem::m_retrans, m_sentList, m_sentSize, and NS_LOG_FUNCTION.

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◆ ResetRenoSack()

void ns3::TcpTxBuffer::ResetRenoSack ( )

Reset the SACKs.

Reset the Scoreboard from all SACK information. This method also works in case the SACKs are set by the Update method.

Definition at line 1198 of file tcp-tx-buffer.cc.

References m_highestSack, m_sackedOut, m_sackSeen, m_sentList, and NS_LOG_FUNCTION.

◆ ResetSentList()

void ns3::TcpTxBuffer::ResetSentList ( )

Reset the sent list.

Definition at line 1220 of file tcp-tx-buffer.cc.

References m_appList, m_highestSack, ns3::TcpTxItem::m_lost, m_lostOut, m_retrans, ns3::TcpTxItem::m_retrans, ns3::TcpTxItem::m_sacked, m_sackedOut, m_sackSeen, m_sentList, m_sentSize, and NS_LOG_FUNCTION.

◆ SetDupAckThresh()

void ns3::TcpTxBuffer::SetDupAckThresh ( uint32_t dupAckThresh )

Set the DupAckThresh.

Parameters

dupAckThresh the threshold

Definition at line 124 of file tcp-tx-buffer.cc.

References m_dupAckThresh.

Referenced by TcpRateLinuxWithBufferTest::TestWithSackBlocks().

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◆ SetHeadSequence()

void ns3::TcpTxBuffer::SetHeadSequence ( const SequenceNumber32 & seq )

Set the head sequence of the buffer.

Set the head (m_firstByteSeq) to seq. Supposed to be called only when the connection is just set up and we did not send any data out yet.

Parameters

seq	The sequence number of the head byte

Definition at line 154 of file tcp-tx-buffer.cc.

References m_firstByteSeq, m_highestSack, m_sackSeen, m_sentList, NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by TcpTxBufferTestCase::TestMergeItemsWhenGetTransmittedSegment(), and TcpRateLinuxWithBufferTest::TestWithSackBlocks().

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◆ SetMaxBufferSize()

void ns3::TcpTxBuffer::SetMaxBufferSize ( uint32_t n )

Set the maximum buffer size.

Parameters

n	Tx window size (in bytes)

Definition at line 100 of file tcp-tx-buffer.cc.

References m_maxBuffer.

◆ SetRWndCallback()

void ns3::TcpTxBuffer::SetRWndCallback ( Callback< uint32_t > rWndCallback )

Set callback to obtain receiver window value.

Parameters

rWndCallback receiver window callback

Definition at line 1213 of file tcp-tx-buffer.cc.

References m_rWndCallback, and NS_LOG_FUNCTION.

◆ SetSackEnabled()

void ns3::TcpTxBuffer::SetSackEnabled ( bool enabled )

tell tx-buffer whether SACK is used on this TCP socket

Parameters

enabled whether sack is used

Definition at line 112 of file tcp-tx-buffer.cc.

References m_sackEnabled.

◆ SetSegmentSize()

void ns3::TcpTxBuffer::SetSegmentSize ( uint32_t segmentSize )

Set the segment size.

Parameters

segmentSize the segment size

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

References m_segmentSize, and segmentSize.

Referenced by TcpTxBufferTestCase::TestMergeItemsWhenGetTransmittedSegment(), and TcpRateLinuxWithBufferTest::TestWithSackBlocks().

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◆ SetSentListLost()

void ns3::TcpTxBuffer::SetSentListLost ( bool resetSack = false )

Set the entire sent list as lost (typically after an RTO)

Used to set all the sent list as lost, so the bytes in flight is not counting them as in flight, but we will continue to use SACK information for recovering the timeout.

Moreover, reset the retransmit flag for every item.

Parameters

resetSack True if the function should reset the SACK flags.

Definition at line 1262 of file tcp-tx-buffer.cc.

References ConsistencyCheck(), m_highestSack, m_lostOut, m_retrans, m_sackedOut, m_sackSeen, m_sentList, m_sentSize, NS_ASSERT_MSG, NS_LOG_FUNCTION, and NS_LOG_INFO.

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◆ Size()

uint32_t ns3::TcpTxBuffer::Size ( ) const

Returns total number of bytes in this buffer.

Returns: total number of bytes in this Tx buffer

Definition at line 88 of file tcp-tx-buffer.cc.

References m_size.

◆ SizeFromSequence()

uint32_t ns3::TcpTxBuffer::SizeFromSequence ( const SequenceNumber32 & seq ) const

Returns the number of bytes from the buffer in the range [seq, tailSequence)

Parameters

seq	initial sequence number

Returns: the number of bytes from the buffer in the range

Definition at line 195 of file tcp-tx-buffer.cc.

References NS_LOG_ERROR, NS_LOG_FUNCTION, and TailSequence().

Referenced by CopyFromSequence(), and NextSeg().

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◆ SplitItems()

void ns3::TcpTxBuffer::SplitItems	(	TcpTxItem *	t1,
		TcpTxItem *	t2,
		uint32_t	size ) const

private

Split one TcpTxItem.

Move "size" bytes from t2 into t1, copying all the fields. Adjust the starting sequence of each item.

Parameters

t1	first item
t2	second item
size	Size to split

Definition at line 370 of file tcp-tx-buffer.cc.

References ns3::Packet::CreateFragment(), ns3::TcpTxItem::m_lastSent, ns3::TcpTxItem::m_lost, ns3::TcpTxItem::m_packet, ns3::TcpTxItem::m_retrans, ns3::TcpTxItem::m_sacked, ns3::TcpTxItem::m_startSeq, NS_ASSERT, NS_LOG_FUNCTION, NS_LOG_INFO, and ns3::Packet::RemoveAtStart().

Referenced by GetPacketFromList().

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◆ TailSequence()

SequenceNumber32 ns3::TcpTxBuffer::TailSequence ( ) const

Get the sequence number of the buffer tail (plus one)

Returns: the last byte's sequence number + 1

Definition at line 82 of file tcp-tx-buffer.cc.

References m_firstByteSeq, and m_size.

Referenced by SizeFromSequence().

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◆ Update()

uint32_t ns3::TcpTxBuffer::Update	(	const TcpOptionSack::SackList &	list,
		const Callback< void, TcpTxItem * > &	sackedCb = m_nullCb )

Update the scoreboard.

Parameters

list	list of SACKed blocks
sackedCb	Callback invoked, if it is not null, when a segment has been SACKed by the receiver.

Returns: the number of bytes newly sacked by the list of blocks

Definition at line 773 of file tcp-tx-buffer.cc.

References ConsistencyCheck(), ns3::Callback< R, UArgs >::IsNull(), m_firstByteSeq, m_highestSack, m_lostOut, m_sackedOut, m_sackSeen, m_sentList, m_sentSize, NS_ASSERT, NS_ASSERT_MSG, NS_LOG_FUNCTION, NS_LOG_INFO, pktSize, and UpdateLostCount().

Referenced by TcpRateLinuxWithBufferTest::TestWithSackBlocks().

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◆ UpdateLostCount()

void ns3::TcpTxBuffer::UpdateLostCount ( )

private

Update the lost count.

Reset lost to 0, then walk the sent list looking for lost segments. We have two possible algorithms for detecting lost packets:

RFC 6675 algorithm, which says that if more than "Dupack thresh" (e.g., 3) sacked segments above the sequence, then we can consider the sequence lost;
NewReno (RFC6582): in Recovery we assume that one segment is lost (classic Reno). While we are in Recovery and a partial ACK arrives, we assume that one more packet is lost (NewReno).

The {New}Reno cases, for now, are managed in TcpSocketBase through the call to MarkHeadAsLost. This function is, therefore, called after a SACK option has been received, and updates the lost count. It can be probably optimized by not walking the entire list, but a subset.

Definition at line 868 of file tcp-tx-buffer.cc.

References ConsistencyCheck(), ns3::Packet::GetSize(), m_dupAckThresh, m_highestSack, ns3::TcpTxItem::m_lost, m_lostOut, ns3::TcpTxItem::m_packet, ns3::TcpTxItem::m_sacked, m_sentList, NS_LOG_FUNCTION, and NS_LOG_INFO.

Referenced by Update().

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Friends And Related Symbol Documentation

◆ operator<<

std::ostream & operator<<	(	std::ostream &	os,
		const TcpTxBuffer &	tcpTxBuf )

friend

Output operator.

Parameters

os	The output stream.
tcpTxBuf	the TcpTxBuffer to print.

Returns: The output stream.

Definition at line 1456 of file tcp-tx-buffer.cc.

Member Data Documentation

◆ m_appList

PacketList ns3::TcpTxBuffer::m_appList

private

Buffer for application data.

Definition at line 594 of file tcp-tx-buffer.h.

Referenced by ~TcpTxBuffer(), Add(), GetNewSegment(), ResetLastSegmentSent(), and ResetSentList().

◆ m_dupAckThresh

uint32_t ns3::TcpTxBuffer::m_dupAckThresh {0}

private

Duplicate Ack threshold from TcpSocketBase.

Definition at line 609 of file tcp-tx-buffer.h.

Referenced by IsLostRFC(), SetDupAckThresh(), and UpdateLostCount().

◆ m_firstByteSeq

TracedValue<SequenceNumber32> ns3::TcpTxBuffer::m_firstByteSeq

private

Sequence number of the first byte in data (SND.UNA)

Definition at line 602 of file tcp-tx-buffer.h.

Referenced by Add(), BytesInFlightRFC(), CopyFromSequence(), DiscardUpTo(), FindHighestSacked(), GetNewSegment(), GetPacketFromList(), GetTransmittedSegment(), GetTypeId(), HeadSequence(), NextSeg(), SetHeadSequence(), TailSequence(), and Update().

◆ m_highestSack

std::pair<PacketList::const_iterator, SequenceNumber32> ns3::TcpTxBuffer::m_highestSack

private

Highest SACK byte.

Definition at line 603 of file tcp-tx-buffer.h.

Referenced by AddRenoSack(), DiscardUpTo(), IsLost(), IsLostRFC(), NextSeg(), ResetRenoSack(), ResetSentList(), SetHeadSequence(), SetSentListLost(), Update(), and UpdateLostCount().

◆ m_lostOut

uint32_t ns3::TcpTxBuffer::m_lostOut {0}

private

Number of lost bytes.

Definition at line 605 of file tcp-tx-buffer.h.

Referenced by BytesInFlight(), BytesInFlightRFC(), ConsistencyCheck(), DiscardUpTo(), GetLost(), MarkHeadAsLost(), RemoveFromCounts(), ResetSentList(), SetSentListLost(), Update(), and UpdateLostCount().

◆ m_maxBuffer

uint32_t ns3::TcpTxBuffer::m_maxBuffer

private

Max number of data bytes in buffer (SND.WND)

Definition at line 596 of file tcp-tx-buffer.h.

Referenced by Available(), MaxBufferSize(), and SetMaxBufferSize().

◆ m_nullCb

Callback< void, TcpTxItem * > ns3::TcpTxBuffer::m_nullCb = MakeNullCallback<void, TcpTxItem*>()

staticprivate

Null callback for an item.

Definition at line 615 of file tcp-tx-buffer.h.

◆ m_renoSack

bool ns3::TcpTxBuffer::m_renoSack {false}

private

Indicates if AddRenoSack was called.

Definition at line 611 of file tcp-tx-buffer.h.

Referenced by AddRenoSack().

◆ m_retrans

uint32_t ns3::TcpTxBuffer::m_retrans {0}

private

Number of retransmitted bytes.

Definition at line 607 of file tcp-tx-buffer.h.

Referenced by BytesInFlight(), BytesInFlightRFC(), ConsistencyCheck(), DeleteRetransmittedFlagFromHead(), DiscardUpTo(), GetRetransmitsCount(), GetTransmittedSegment(), MarkHeadAsLost(), MergeItems(), RemoveFromCounts(), ResetLastSegmentSent(), ResetSentList(), and SetSentListLost().

◆ m_rWndCallback

Callback<uint32_t> ns3::TcpTxBuffer::m_rWndCallback

private

Callback to obtain RCV.WND value.

Definition at line 599 of file tcp-tx-buffer.h.

Referenced by TcpTxBuffer(), NextSeg(), and SetRWndCallback().

◆ m_sackedOut

uint32_t ns3::TcpTxBuffer::m_sackedOut {0}

private

Number of sacked bytes.

Definition at line 606 of file tcp-tx-buffer.h.

Referenced by AddRenoSack(), BytesInFlight(), BytesInFlightRFC(), ConsistencyCheck(), DiscardUpTo(), GetSacked(), MarkHeadAsLost(), RemoveFromCounts(), ResetRenoSack(), ResetSentList(), SetSentListLost(), and Update().

◆ m_sackEnabled

bool ns3::TcpTxBuffer::m_sackEnabled {true}

private

Indicates if SACK is enabled on this connection.

Definition at line 612 of file tcp-tx-buffer.h.

Referenced by AddRenoSack(), IsSackEnabled(), and SetSackEnabled().

◆ m_sackSeen

bool ns3::TcpTxBuffer::m_sackSeen {false}

private

Indicates if a SACK was received.

Definition at line 613 of file tcp-tx-buffer.h.

Referenced by AddRenoSack(), DiscardUpTo(), NextSeg(), ResetRenoSack(), ResetSentList(), SetHeadSequence(), SetSentListLost(), and Update().

◆ m_segmentSize

uint32_t ns3::TcpTxBuffer::m_segmentSize {0}

private

Segment size from TcpSocketBase.

Definition at line 610 of file tcp-tx-buffer.h.

Referenced by IsLostRFC(), NextSeg(), and SetSegmentSize().

◆ m_sentList

PacketList ns3::TcpTxBuffer::m_sentList

private

Buffer for sent (but not acked) data.

Definition at line 595 of file tcp-tx-buffer.h.

Referenced by ~TcpTxBuffer(), AddRenoSack(), BytesInFlightRFC(), ConsistencyCheck(), DeleteRetransmittedFlagFromHead(), DiscardUpTo(), FindHighestSacked(), GetNewSegment(), GetPacketFromList(), GetTransmittedSegment(), IsHeadRetransmitted(), IsLost(), IsLostRFC(), IsRetransmittedDataAcked(), MarkHeadAsLost(), NextSeg(), ResetLastSegmentSent(), ResetRenoSack(), ResetSentList(), SetHeadSequence(), SetSentListLost(), Update(), and UpdateLostCount().

◆ m_sentSize

uint32_t ns3::TcpTxBuffer::m_sentSize

private

Size of sent (and not discarded) segments.

Definition at line 598 of file tcp-tx-buffer.h.

Referenced by ~TcpTxBuffer(), BytesInFlight(), BytesInFlightRFC(), CopyFromSequence(), DeleteRetransmittedFlagFromHead(), DiscardUpTo(), GetNewSegment(), GetTransmittedSegment(), IsHeadRetransmitted(), NextSeg(), ResetLastSegmentSent(), ResetSentList(), SetSentListLost(), and Update().

◆ m_size

uint32_t ns3::TcpTxBuffer::m_size

private

Size of all data in this buffer.

Definition at line 597 of file tcp-tx-buffer.h.

Referenced by ~TcpTxBuffer(), Add(), Available(), DiscardUpTo(), Size(), and TailSequence().

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

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

Public Member Functions

Static Public Member Functions

Private Types

Private Member Functions

Private Attributes

Static Private Attributes

Friends

Additional Inherited Members

Detailed Description

SACK management

Item properties

Management of bytes in flight

Lost segments

Member Typedef Documentation

◆ PacketList

Constructor & Destructor Documentation

◆ TcpTxBuffer()

◆ ~TcpTxBuffer()

Member Function Documentation

◆ Add()

◆ AddRenoSack()

◆ Available()

◆ BytesInFlight()

◆ BytesInFlightRFC()

◆ ConsistencyCheck()

◆ CopyFromSequence()

◆ DeleteRetransmittedFlagFromHead()

◆ DiscardUpTo()

◆ FindHighestSacked()

◆ GetLost()

◆ GetNewSegment()

◆ GetPacketFromList()

◆ GetRetransmitsCount()

◆ GetSacked()

◆ GetTransmittedSegment()

◆ GetTypeId()

◆ HeadSequence()

◆ IsHeadRetransmitted()

◆ IsLost()

◆ IsLostRFC()

◆ IsRetransmittedDataAcked()

◆ IsSackEnabled()

◆ MarkHeadAsLost()

◆ MaxBufferSize()

◆ MergeItems()

◆ NextSeg()

◆ RemoveFromCounts()

◆ ResetLastSegmentSent()

◆ ResetRenoSack()

◆ ResetSentList()

◆ SetDupAckThresh()

◆ SetHeadSequence()

◆ SetMaxBufferSize()

◆ SetRWndCallback()

◆ SetSackEnabled()

◆ SetSegmentSize()

◆ SetSentListLost()

◆ Size()

◆ SizeFromSequence()

◆ SplitItems()

◆ TailSequence()

◆ Update()

◆ UpdateLostCount()

Friends And Related Symbol Documentation

◆ operator<<

Member Data Documentation

◆ m_appList

◆ m_dupAckThresh

◆ m_firstByteSeq

◆ m_highestSack

◆ m_lostOut

◆ m_maxBuffer

◆ m_nullCb

◆ m_renoSack

◆ m_retrans

◆ m_rWndCallback

◆ m_sackedOut

◆ m_sackEnabled

◆ m_sackSeen

◆ m_segmentSize