handle packet metadata about packet headers and trailers More...

#include <packet-metadata.h>

Classes
struct	Data

class	DataFreeList

struct	ExtraItem

struct	Item

class	ItemIterator

struct	SmallItem

Public Member Functions
	PacketMetadata (uint64_t uid, uint32_t size)

	PacketMetadata (PacketMetadata const &o)

void	AddAtEnd (PacketMetadata const &o)

void	AddHeader (Header const &header, uint32_t size)

void	AddPaddingAtEnd (uint32_t end)

void	AddTrailer (Trailer const &trailer, uint32_t size)

ItemIterator	BeginItem (Buffer buffer) const

PacketMetadata	CreateFragment (uint32_t start, uint32_t end) const

uint32_t	Deserialize (const uint8_t *buffer, uint32_t size)

uint32_t	GetSerializedSize (void) const

uint64_t	GetUid (void) const

PacketMetadata &	operator= (PacketMetadata const &o)

void	RemoveAtEnd (uint32_t end)

void	RemoveAtStart (uint32_t start)

void	RemoveHeader (Header const &header, uint32_t size)

void	RemoveTrailer (Trailer const &trailer, uint32_t size)

uint32_t	Serialize (uint8_t *buffer, uint32_t maxSize) const

Static Public Member Functions
static void	Enable (void)

static void	EnableChecking (void)

Private Member Functions
uint16_t	AddBig (uint32_t head, uint32_t tail, const PacketMetadata::SmallItem item, const PacketMetadata::ExtraItem extraItem)

uint16_t	AddSmall (const PacketMetadata::SmallItem *item)

void	Append16 (uint16_t value, uint8_t *buffer)

void	Append32 (uint32_t value, uint8_t *buffer)

void	AppendValue (uint32_t value, uint8_t *buffer)

void	AppendValueExtra (uint32_t value, uint8_t *buffer)

void	DoAddHeader (uint32_t uid, uint32_t size)

uint32_t	GetTotalSize (void) const

uint32_t	GetUleb128Size (uint32_t value) const

bool	IsPointerOk (uint16_t pointer) const

bool	IsSharedPointerOk (uint16_t pointer) const

bool	IsStateOk (void) const

uint32_t	ReadItems (uint16_t current, struct PacketMetadata::SmallItem item, struct PacketMetadata::ExtraItem extraItem) const

uint32_t	ReadUleb128 (const uint8_t **pBuffer) const

void	ReplaceTail (PacketMetadata::SmallItem item, PacketMetadata::ExtraItem extraItem, uint32_t available)

void	Reserve (uint32_t n)

void	ReserveCopy (uint32_t n)

void	UpdateHead (uint16_t written)

void	UpdateTail (uint16_t written)

Static Private Member Functions
static uint8_t *	AddToRaw (const uint8_t data, uint32_t dataSize, uint8_t start, uint8_t *current, uint32_t maxSize)

static uint8_t *	AddToRawU16 (const uint16_t &data, uint8_t start, uint8_t current, uint32_t maxSize)

static uint8_t *	AddToRawU32 (const uint32_t &data, uint8_t start, uint8_t current, uint32_t maxSize)

static uint8_t *	AddToRawU64 (const uint64_t &data, uint8_t start, uint8_t current, uint32_t maxSize)

static uint8_t *	AddToRawU8 (const uint8_t &data, uint8_t start, uint8_t current, uint32_t maxSize)

static struct PacketMetadata::Data *	Allocate (uint32_t n)

static struct PacketMetadata::Data *	Create (uint32_t size)

static void	Deallocate (struct PacketMetadata::Data *data)

static uint8_t *	ReadFromRawU16 (uint16_t &data, const uint8_t start, const uint8_t current, uint32_t maxSize)

static uint8_t *	ReadFromRawU32 (uint32_t &data, const uint8_t start, const uint8_t current, uint32_t maxSize)

static uint8_t *	ReadFromRawU64 (uint64_t &data, const uint8_t start, const uint8_t current, uint32_t maxSize)

static uint8_t *	ReadFromRawU8 (uint8_t &data, const uint8_t start, const uint8_t current, uint32_t maxSize)

static void	Recycle (struct PacketMetadata::Data *data)

Private Attributes
struct Data *	m_data

uint16_t	m_head

uint64_t	m_packetUid

uint16_t	m_tail

uint16_t	m_used

Static Private Attributes
static uint16_t	m_chunkUid = 0

static bool	m_enable = false

static bool	m_enableChecking = false

static DataFreeList	m_freeList

static uint32_t	m_maxSize = 0

static bool	m_metadataSkipped = false

Friends
class	ItemIterator

Detailed Description

handle packet metadata about packet headers and trailers

This class is used by the Packet class to record every operation performed on the packet's buffer. This class also provides an implementation of the Packet::Print methods which uses the metadata to analyse the content of the packet's buffer.

To achieve this, this class maintains a linked list of so-called "items", each of which represents a header or a trailer, or payload, or a fragment of any of these. Each item contains a "next" and a "prev" field which point to the next and previous entries in the linked list. The PacketMetadata class maintains a pair of pointers to the head and the tail of the linked list.

Each entry in the list also maintains:

its native size (the size it had when it was first added to the packet)
its type: identifies what kind of header, what kind of trailer, if it is payload or not
the uid of the packet to which it was first added
the start and end of the area represented by a fragment if it is one.

This linked list is flattened in a byte buffer stored in struct PacketMetadata::Data. Each entry of the linked list is identified by an offset which identifies the first byte of the entry from the start of the data buffer. The size of this data buffer is 2^16-1 bytes maximum which somewhat limits the number of entries which can be stored in this linked list but it is quite unlikely to hit this limit in practice.

Each item of the linked list is a variable-sized byte buffer made of a number of fields. Some of these fields are stored as fixed-size 32 bit integers, others as fixed-size 16 bit integers, and some others as variable-size 32-bit integers. The variable-size 32 bit integers are stored using the uleb128 encoding.

Definition at line 79 of file packet-metadata.h.

Member Function Documentation

PacketMetadata ns3::PacketMetadata::CreateFragment	(	uint32_t	start,
		uint32_t	end
	)		const

Parameters

start	the amount of stuff to remove from the start
end	the amount of stuff to remove from the end

Calling this method is equivalent to calling RemoveAtStart (start) and then, RemoveAtEnd (end).

Definition at line 656 of file packet-metadata.cc.

References NS_LOG_FUNCTION.

Referenced by ns3::Packet::CreateFragment().

uint32_t ns3::PacketMetadata::ReadItems	(	uint16_t	current,
		struct PacketMetadata::SmallItem *	item,
		struct PacketMetadata::ExtraItem *	extraItem
	)		const

private

Parameters

current	the offset we should start reading the data from
item	pointer to where we should store the data to return to the caller
extraItem	pointer to where we should store the data to return to the caller

Returns: the number of bytes read.

Definition at line 540 of file packet-metadata.cc.

References NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by ReplaceTail().

void ns3::PacketMetadata::ReplaceTail	(	PacketMetadata::SmallItem *	item,
		PacketMetadata::ExtraItem *	extraItem,
		uint32_t	available
	)

private

Parameters

item	the item data to write
extraItem	the extra item data to write
available	the number of bytes which can be written without having to rewrite the buffer entirely.

Definition at line 457 of file packet-metadata.cc.

References m_head, NS_ASSERT, NS_LOG_FUNCTION, and ReadItems().

Member Data Documentation

uint16_t ns3::PacketMetadata::m_head

private

head -(next)-> tail ^ | -–(prev)—|

Definition at line 356 of file packet-metadata.h.

Referenced by ReplaceTail().

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

src/network/model/packet-metadata.h
src/network/model/packet-metadata.cc

Classes

Public Member Functions

Static Public Member Functions

Private Member Functions

Static Private Member Functions

Private Attributes

Static Private Attributes

Friends

Detailed Description

Member Function Documentation

Member Data Documentation