A network packet believed not to be shared. More...

Inheritance diagram for WritablePacket:

Public Member Functions
unsigned char *	data () const

unsigned char *	end_data () const

unsigned char *	buffer () const

unsigned char *	end_buffer () const

unsigned char *	mac_header () const

click_ether *	ether_header () const

unsigned char *	network_header () const

click_ip *	ip_header () const

click_ip6 *	ip6_header () const

unsigned char *	transport_header () const

click_icmp *	icmp_header () const

click_tcp *	tcp_header () const

click_udp *	udp_header () const

unsigned char *	getPacketContent ()

void	rewrite_ips (IPPair pair, bool is_tcp=true)

void	rewrite_ips_ports (IPPair pair, uint16_t sport, uint16_t dport, bool is_tcp=true)

void	rewrite_ipport (IPAddress ip, uint16_t port, const int shift, bool is_tcp=true)

void	rewrite_ip (IPAddress ip, const int shift, bool is_tcp=true)

void	rewrite_seq (tcp_seq_t seq, const int shift)

WritablePacket *	unique_next ()

WritablePacket *	unique_prev ()

	WritablePacket (const Packet &x)

Public Member Functions inherited from Packet
void	kill ()
	Delete this packet.

void	kill_nonatomic ()
	Delete this packet in a thread-safe context.

bool	shared () const
	Test whether this packet's data is shared.

bool	shared_nonatomic () const
	Test whether this packet's data is shared.

Packet *	clone (bool fast=false)
	Create a clone of this packet.

WritablePacket *	duplicate (int32_t extra_headroom=0, int32_t extra_tailroom=0, const bool data_only=true)

WritablePacket *	uniqueify ()
	Return an unshared packet containing this packet's data.

void	get ()

const unsigned char *	data () const
	Return the packet's data pointer.

const unsigned char *	end_data () const
	Return the packet's end data pointer.

uint32_t	length () const
	Return the packet's length.

uint32_t	headroom () const
	Return the packet's headroom.

uint32_t	tailroom () const
	Return the packet's tailroom.

const unsigned char *	buffer () const
	Return a pointer to the packet's data buffer.

const unsigned char *	end_buffer () const
	Return the packet's end data buffer pointer.

uint32_t	buffer_length () const
	Return the packet's buffer length.

struct sk_buff *	skb ()

const struct sk_buff *	skb () const

WritablePacket *	push (uint32_t len)
	Add space for a header before the packet.

WritablePacket *	push_mac_header (uint32_t len)
	Add space for a MAC header before the packet.

Packet *	nonunique_push (uint32_t len)
	Add space for a header before the packet.

void	pull (uint32_t len)
	Remove a header from the front of the packet.

WritablePacket *	put (uint32_t len)
	Add space for data after the packet.

Packet *	nonunique_put (uint32_t len)
	Add space for data after the packet.

void	take (uint32_t len)
	Remove space from the end of the packet.

Packet *	shift_data (int offset, bool free_on_failure=true)
	Shift packet data within the data buffer.

void	shrink_data (const unsigned char *data, uint32_t length)
	Shrink the packet's data.

void	change_headroom_and_length (uint32_t headroom, uint32_t length)
	Shift the packet's data view to a different part of its buffer.

void	change_buffer_length (uint32_t length)

bool	copy (Packet *p, int headroom=0)
	Copy the content and annotations of another packet (userlevel) into this packet.

const Timestamp &	timestamp_anno () const
	Return the timestamp annotation.

Timestamp &	timestamp_anno ()

void	set_timestamp_anno (const Timestamp &t)
	Set the timestamp annotation.

net_device *	device_anno () const
	Return the device annotation.

void	set_device_anno (net_device *dev)
	Set the device annotation.

PacketType	packet_type_anno () const
	Return the packet type annotation.

void	set_packet_type_anno (PacketType t)
	Set the packet type annotation.

Packet *	next () const
	Return the next packet annotation.

Packet *&	next ()

void	set_next (Packet *p)
	Set the next packet annotation.

Packet *	prev () const
	Return the previous packet annotation.

Packet *&	prev ()

void	set_prev (Packet *p)
	Set the previous packet annotation.

Packet *	find_tail ()

unsigned int	find_count ()

IPAddress	dst_ip_anno () const
	Return the destination IPv4 address annotation.

void	set_dst_ip_anno (IPAddress addr)
	Set the destination IPv4 address annotation.

void *	anno ()
	Return a pointer to the annotation area.

const void *	anno () const

uint8_t *	anno_u8 ()
	Return a pointer to the annotation area as uint8_ts.

const uint8_t *	anno_u8 () const
	overload

uint32_t *	anno_u32 ()
	Return a pointer to the annotation area as uint32_ts.

const uint32_t *	anno_u32 () const
	overload

uint8_t	anno_u8 (int i) const
	Return annotation byte at offset i.

void	set_anno_u8 (int i, uint8_t x)
	Set annotation byte at offset i.

uint16_t	anno_u16 (int i) const
	Return 16-bit annotation at offset i.

void	set_anno_u16 (int i, uint16_t x)
	Set 16-bit annotation at offset i.

int16_t	anno_s16 (int i) const
	Return 16-bit annotation at offset i.

void	set_anno_s16 (int i, int16_t x)
	Set 16-bit annotation at offset i.

uint32_t	anno_u32 (int i) const
	Return 32-bit annotation at offset i.

void	set_anno_u32 (int i, uint32_t x)
	Set 32-bit annotation at offset i.

int32_t	anno_s32 (int i) const
	Return 32-bit annotation at offset i.

void	set_anno_s32 (int i, int32_t x)
	Set 32-bit annotation at offset i.

uint64_t	anno_u64 (int i) const
	Return 64-bit annotation at offset i.

void	set_anno_u64 (int i, uint64_t x)
	Set 64-bit annotation at offset i.

void *	anno_ptr (int i) const
	Return void * sized annotation at offset i.

void	set_anno_ptr (int i, const void *x)
	Set void * sized annotation at offset i.

Packet *	data_packet ()

void	clear_annotations (bool all=true)
	Clear all packet annotations.

void	copy_annotations (const Packet *, bool all=true)
	Copy most packet annotations from p.

void	copy_headers (const Packet *)

bool	has_mac_header () const
	Return true iff the packet's MAC header pointer is set.

const unsigned char *	mac_header () const
	Return the packet's MAC header pointer.

int	mac_header_offset () const
	Return the offset from the packet data to the MAC header.

uint32_t	mac_header_length () const
	Return the MAC header length.

int	mac_length () const
	Return the packet's length starting from its MAC header pointer.

void	set_mac_header (const unsigned char *p)
	Set the MAC header pointer.

void	set_mac_header (const unsigned char *p, uint32_t len)
	Set the MAC and network header pointers.

void	clear_mac_header ()
	Unset the MAC header pointer.

bool	has_network_header () const
	Return true iff the packet's network header pointer is set.

const unsigned char *	network_header () const
	Return the packet's network header pointer.

int	network_header_offset () const
	Return the offset from the packet data to the network header.

uint32_t	network_header_length () const
	Return the network header length.

int	network_length () const
	Return the packet's length starting from its network header pointer.

void	set_network_header (const unsigned char *p)
	Set the network header.

void	set_network_header (const unsigned char *p, uint32_t len)
	Set the network and transport header pointers.

void	set_network_header_length (uint32_t len)
	Set the network header length.

void	clear_network_header ()
	Unset the network header pointer.

void	set_transport_header (const unsigned char *p)
	Set the transport header.

bool	has_transport_header () const
	Return true iff the packet's transport header pointer is set.

const unsigned char *	transport_header () const
	Return the packet's transport header pointer.

int	transport_header_offset () const
	Return the offset from the packet data to the transport header.

int	transport_length () const
	Return the packet's length starting from its transport header pointer.

void	clear_transport_header ()
	Unset the transport header pointer.

const click_ether *	ether_header () const
	Return the packet's MAC header pointer as Ethernet.

void	set_ether_header (const click_ether *ethh)
	Set the MAC header pointer to an Ethernet header.

const click_ip *	ip_header () const
	Return the packet's network header pointer as IPv4.

int	ip_header_offset () const
	Return the offset from the packet data to the IP header.

uint32_t	ip_header_length () const
	Return the IP header length.

void	set_ip_header (const click_ip *iph, uint32_t len)
	Set the network header pointer to an IPv4 header.

const click_ip6 *	ip6_header () const
	Return the packet's network header pointer as IPv6.

int	ip6_header_offset () const
	Return the offset from the packet data to the IPv6 header.

uint32_t	ip6_header_length () const
	Return the IPv6 header length.

void	set_ip6_header (const click_ip6 *ip6h)
	Set the network header pointer to an IPv6 header.

void	set_ip6_header (const click_ip6 *ip6h, uint32_t len)
	Set the network header pointer to an IPv6 header.

const click_icmp *	icmp_header () const
	Return the packet's transport header pointer as ICMP.

const click_tcp *	tcp_header () const
	Return the packet's transport header pointer as TCP.

const click_udp *	udp_header () const
	Return the packet's transport header pointer as UDP.

uint16_t	getContentOffset () const

void	setContentOffset (uint16_t offset)

const unsigned char *	getPacketContent ()

bool	isPacketContentEmpty () const

uint16_t	getPacketContentSize () const

Static Public Member Functions
static void	pool_transfer (int from, int to)

static WritablePacket *	pool_prepare_data_burst (uint16_t count)

static void	pool_consumed_data_burst (uint16_t n, WritablePacket *tail)

Static Public Member Functions inherited from Packet
static WritablePacket *	make (uint32_t headroom, const void *data, uint32_t length, uint32_t tailroom, bool clear=true)
	Create and return a new packet.

static WritablePacket *	make (const void *data, uint32_t length)
	Create and return a new packet.

static WritablePacket *	make (uint32_t length)
	Create and return a new packet.

static WritablePacket *	make_similar (Packet *original, uint32_t length)

static Packet *	make (struct sk_buff *skb)
	Change an sk_buff into a Packet (linuxmodule).

static void	empty_destructor (unsigned char , size_t, void )

static WritablePacket *	make (unsigned char data, uint32_t length, buffer_destructor_type buffer_destructor, void argument=(void *) 0, int headroom=0, int tailroom=0, bool clear=true)
	Create and return a new packet (userlevel).

static int	max_data_pool_size ()

static void	static_cleanup ()

Additional Inherited Members
Public Types inherited from Packet
enum	{ default_headroom = 28 , min_buffer_length = 64 }

typedef void(*	buffer_destructor_type) (unsigned char buf, size_t sz, void argument)

enum	{ anno_size = 48 }

enum	PacketType { HOST = 0 , BROADCAST = 1 , MULTICAST = 2 , OTHERHOST = 3 , OUTGOING = 4 , LOOPBACK = 5 , FASTROUTE = 6 }
	Values for packet_type_anno(). Must agree with Linux's PACKET_ constants in <linux/if_packet.h>. More...

enum	{ dst_ip_anno_offset = 0 , dst_ip_anno_size = 4 , dst_ip6_anno_offset = 0 , dst_ip6_anno_size = 16 }

Protected Member Functions inherited from Packet
typedef	typeof (((struct sk_buff *) 0) ->mac_header) mac_header_type

typedef	typeof (((struct sk_buff *) 0) ->network_header) network_header_type

typedef	typeof (((struct sk_buff *) 0) ->transport_header) transport_header_type

Detailed Description

A network packet believed not to be shared.

The WritablePacket type represents Packet objects whose data buffers are not shared. As a result, WritablePacket's versions of functions that access the packet data buffer, such as data(), end_buffer(), and ip_header(), return mutable pointers (char * rather than const char *).

WritablePacket objects are created by Packet::make(), Packet::uniqueify(), Packet::push(), and Packet::put(), which ensure that the returned packet does not share its data buffer.

WritablePacket's interface is the same as Packet's except for these type differences. For documentation, see Packet.

Warning: The WritablePacket convention reduces the likelihood of error when modifying packet data, but does not eliminate it. For instance, by calling WritablePacket::clone(), it is possible to create a WritablePacket whose data is shared:
Packet *p = ...;

if (WritablePacket *q = p->uniqueify()) {

Packet *p2 = q->clone();

assert(p2);

q->ip_header()->ip_v = 6; // modifies p2's data as well

}

Packet
A network packet.
Definition packet.hh:68

Packet::uniqueify
WritablePacket * uniqueify()
Return an unshared packet containing this packet's data.
Definition packet.hh:2058

Packet::clone
Packet * clone(bool fast=false)
Create a clone of this packet.
Definition packet.cc:1104

WritablePacket
A network packet believed not to be shared.
Definition packet.hh:1004

Avoid writing buggy code like this! Use WritablePacket selectively, and try to avoid calling WritablePacket::clone() when possible.

Member Function Documentation

◆ data()

unsigned char * WritablePacket::data ( ) const

inline

never

◆ rewrite_ips()

void WritablePacket::rewrite_ips	(	IPPair	pair,
		bool	is_tcp = `true`
	)

inline

never

◆ pool_transfer()

void WritablePacket::pool_transfer	(	int	from,
		int	to
	)

static

Give a hint that some packets from one thread will switch to another thread

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

include/click/packet.hh
lib/packet.cc

Public Member Functions

Static Public Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ data()

◆ rewrite_ips()

◆ pool_transfer()