Base class for protocol data units. More...

#include <pdu.h>

Inheritance diagram for Tins::PDU:

Classes
struct	metadata
	Type used to store a PDU header's data. More...

Public Types
enum	endian_type { BE, LE }

enum	PDUType { RAW, ETHERNET_II, IEEE802_3, DOT3 = IEEE802_3, RADIOTAP, DOT11, DOT11_ACK, DOT11_ASSOC_REQ, DOT11_ASSOC_RESP, DOT11_AUTH, DOT11_BEACON, DOT11_BLOCK_ACK, DOT11_BLOCK_ACK_REQ, DOT11_CF_END, DOT11_DATA, DOT11_CONTROL, DOT11_DEAUTH, DOT11_DIASSOC, DOT11_END_CF_ACK, DOT11_MANAGEMENT, DOT11_PROBE_REQ, DOT11_PROBE_RESP, DOT11_PS_POLL, DOT11_REASSOC_REQ, DOT11_REASSOC_RESP, DOT11_RTS, DOT11_QOS_DATA, LLC, SNAP, IP, ARP, TCP, UDP, ICMP, BOOTP, DHCP, EAPOL, RC4EAPOL, RSNEAPOL, DNS, LOOPBACK, IPv6, ICMPv6, SLL, DHCPv6, DOT1Q, PPPOE, STP, PPI, IPSEC_AH, IPSEC_ESP, PKTAP, MPLS, UNKNOWN = 999, USER_DEFINED_PDU = 1000 }
	Enum which identifies each type of PDU. More...

typedef byte_array	serialization_type

Public Member Functions
	PDU ()
	Default constructor.

	PDU (PDU &&rhs) TINS_NOEXCEPT
	Move constructor. More...

PDU &	operator= (PDU &&rhs) TINS_NOEXCEPT
	Move assignment operator. More...

virtual	~PDU ()
	PDU destructor. More...

virtual uint32_t	header_size () const =0
	The header's size.

virtual uint32_t	trailer_size () const
	Trailer's size. More...

uint32_t	size () const
	The whole chain of PDU's size, including this one. More...

PDU *	inner_pdu () const
	Getter for the inner PDU. More...

PDU *	parent_pdu () const

PDU *	release_inner_pdu ()
	Releases the inner PDU. More...

void	inner_pdu (PDU *next_pdu)
	Sets the child PDU. More...

void	inner_pdu (const PDU &next_pdu)
	Sets the child PDU. More...

serialization_type	serialize ()
	Serializes the whole chain of PDU's, including this one. More...

template<typename T >
T *	find_pdu (PDUType type=T::pdu_flag)
	Finds and returns the first PDU that matches the given flag. More...

template<typename T >
const T *	find_pdu (PDUType type=T::pdu_flag) const
	Finds and returns the first PDU that matches the given flag. More...

template<typename T >
T &	rfind_pdu (PDUType type=T::pdu_flag)
	Finds and returns the first PDU that matches the given flag. More...

template<typename T >
const T &	rfind_pdu (PDUType type=T::pdu_flag) const
	Finds and returns the first PDU that matches the given flag. More...

virtual PDU *	clone () const =0
	Clones this packet. More...

virtual void	send (PacketSender &sender, const NetworkInterface &iface)
	Send the stack of PDUs through a PacketSender. More...

virtual PDU *	recv_response (PacketSender &sender, const NetworkInterface &iface)
	Receives a matching response for this packet. More...

virtual bool	matches_response (const uint8_t *ptr, uint32_t total_sz) const
	Check whether ptr points to a valid response for this PDU. More...

virtual bool	matches_flag (PDUType flag) const
	Check whether this PDU matches the specified flag. More...

virtual PDUType	pdu_type () const =0
	Getter for the PDU's type. More...

Static Public Attributes
static const endian_type	endianness = BE

Protected Member Functions
	PDU (const PDU &other)
	Copy constructor.

PDU &	operator= (const PDU &other)
	Copy assignment operator.

void	copy_inner_pdu (const PDU &pdu)
	Copy other PDU's inner PDU(if any). More...

virtual void	prepare_for_serialize ()
	Prepares this PDU for serialization. More...

void	serialize (uint8_t *buffer, uint32_t total_sz)
	Serializes this PDU and propagates this action to child PDUs. More...

virtual void	write_serialization (uint8_t *buffer, uint32_t total_sz)=0
	Serializes this TCP PDU. More...

Detailed Description

Base class for protocol data units.

Represents a PDU which holds raw data.

Every PDU implementation inherits from this class.

PDUs can contain 0 or 1 inner PDU. By stacking several PDUs together, you can construct packets. These are created upwards: upper layers will be children of the lower ones.

If you want to find a specific protocol within a PDU chain, you can use PDU::find_pdu and PDU::rfind_pdu. Both of them take a template parameter that indicates the PDU type you are looking for. The first one returns a pointer to the first object of that type, and the second one returns a reference (and throws if it is not found).

For example:

// Take a whole packet from somewhere.
EthernetII packet = ...;
// Find the IP layer
const IP* ip = packet.find_pdu<IP>();
if(ip) {
    // If the pointer is not null, then it will point to the IP layer
}
// Find the TCP layer. This will throw a pdu_not_found exception
// if there is no TCP layer in this packet.
const TCP& tcp = packet.rfind_pdu<TCP>();

PDU objects can be serialized. Serialization converts the entire PDU stack into a vector of bytes. This process might modify some parameters on packets depending on which protocols are used in it. For example:

If the lowest protocol layer is IP (this means that there is no link layer protocol in the packet), then it calculates the source address that should be used in that IP PDU.
See also
IP
If a protocol contains a checksum field, its value will be calculated and included in its serialized contents.
If a protocol contains a "next protocol" field, it is also set based on the type of the next PDU in the packet.

If you want to serialize a packet, just use PDU::serialize:

// Construct a packet
EthernetII packet = EthernetII() / IP() / TCP() / RawPDU("hello");
// Now serialize it. This is a std::vector<uint8_t>.
PDU::serialization_type buffer = packet.serialize();

This class is a wrapper over a byte array. It can be used to hold the payload sent over transport layer protocols (such as TCP or UDP).

While sniffing, this class is the one that will hold transport layer protocols' payload. You can simply convert a RawPDU into a specific application layer protocol using the RawPDU::to method:

// Get a RawPDU from somewhere
RawPDU raw = get_raw_pdu();
// Parse it as a DHCP PDU.
DHCP dhcp = raw.to<DHCP>();
// Or parse it as DNS. Of course this will fail if the contents
// don't look like DNS
DNS dns = raw.to<DNS>();

Member Typedef Documentation

typedef byte_array Tins::PDU::serialization_type

The type that will be returned when serializing PDUs.

Member Enumeration Documentation

enum Tins::PDU::endian_type

The typep used to identify the endianness of every PDU.

enum Tins::PDU::PDUType

Enum which identifies each type of PDU.

This enum is used to identify the PDU type.

Constructor & Destructor Documentation

Tins::PDU::PDU ( PDU && rhs )

inline

Move constructor.

Parameters

rhs	The PDU to be moved.

Tins::PDU::~PDU ( )

virtual

PDU destructor.

Deletes the inner pdu, as a consequence every child pdu is deleted.

Member Function Documentation

virtual PDU* Tins::PDU::clone ( ) const

pure virtual

Clones this packet.

This method clones this PDU and clones every inner PDU, therefore obtaining a clone of the whole inner PDU chain. The pointer returned must be deleted by the user.

Returns: A pointer to a clone of this packet.

Implemented in Tins::ICMPv6, Tins::DNS, Tins::DHCPv6, Tins::RSNEAPOL, Tins::Dot11BlockAck, Tins::IP, Tins::Dot11ReAssocResponse, Tins::Dot11BlockAckRequest, Tins::TCP, Tins::Dot11ReAssocRequest, Tins::DHCP, Tins::Dot11, Tins::ICMP, Tins::Dot11Ack, Tins::RadioTap, Tins::Dot11EndCFAck, Tins::Dot11AssocResponse, Tins::RC4EAPOL, Tins::LLC, Tins::Dot11QoSData, Tins::IPv6, Tins::Dot11CFEnd, Tins::ARP, Tins::BootP, Tins::Dot11PSPoll, Tins::Dot11Deauthentication, Tins::IPSecESP, Tins::Dot11Data, Tins::Dot11AssocRequest, Tins::Dot11ProbeResponse, Tins::RawPDU, Tins::Dot11RTS, Tins::EthernetII, Tins::STP, Tins::Dot3, Tins::PPPoE, Tins::UDP, Tins::SNAP, Tins::SLL, Tins::IPSecAH, Tins::Dot11Authentication, Tins::Dot11Beacon, Tins::MPLS, Tins::Dot1Q, Tins::Dot11Disassoc, Tins::Loopback, Tins::Dot11ProbeRequest, and Tins::PDUCacher< T >.

void Tins::PDU::copy_inner_pdu ( const PDU & pdu )

protected

Copy other PDU's inner PDU(if any).

Parameters

pdu	The PDU from which to copy the inner PDU.

template<typename T >

T* Tins::PDU::find_pdu ( PDUType type = T::pdu_flag )

inline

Finds and returns the first PDU that matches the given flag.

This method searches for the first PDU which has the same type flag as the given one. If the first PDU matches that flag, it is returned. If no PDU matches, 0 is returned.

Parameters

flag	The flag which being searched.

template<typename T >

const T* Tins::PDU::find_pdu ( PDUType type = T::pdu_flag ) const

inline

Finds and returns the first PDU that matches the given flag.

Parameters

flag	The flag which being searched.

PDU* Tins::PDU::inner_pdu ( ) const

inline

Getter for the inner PDU.

Returns: The current inner PDU. Might be a null pointer.

void Tins::PDU::inner_pdu ( PDU * next_pdu )

Sets the child PDU.

When setting a new inner_pdu, the instance takesownership of the object, therefore deleting it when it's no longer required.

Parameters

next_pdu The new child PDU.

void Tins::PDU::inner_pdu ( const PDU & next_pdu )

Sets the child PDU.

The PDU parameter is cloned using PDU::clone.

Parameters

next_pdu The new child PDU.

virtual bool Tins::PDU::matches_flag ( PDUType flag ) const

inlinevirtual

Check whether this PDU matches the specified flag.

This method should be reimplemented in PDU classes which have subclasses, and try to match the given PDU to each of its parent classes' flag.

Parameters

flag	The flag to match.

Reimplemented in Tins::Dot11ManagementFrame, Tins::RSNEAPOL, Tins::Dot11BlockAck, Tins::Dot11ReAssocResponse, Tins::Dot11BlockAckRequest, Tins::Dot11ReAssocRequest, Tins::Dot11, Tins::Dot11Ack, Tins::Dot11EndCFAck, Tins::Dot11AssocResponse, Tins::RC4EAPOL, Tins::Dot11QoSData, Tins::Dot11CFEnd, Tins::Dot11PSPoll, Tins::Dot11Deauthentication, Tins::Dot11Data, Tins::Dot11AssocRequest, Tins::Dot11ProbeResponse, Tins::Dot11RTS, Tins::Dot11Authentication, Tins::Dot11Beacon, Tins::PDUCacher< T >, Tins::Dot11Disassoc, Tins::Dot11ProbeRequest, and Tins::Dot11Control.

bool Tins::PDU::matches_response	(	const uint8_t *	ptr,
		uint32_t	total_sz
	)		const

virtual

Check whether ptr points to a valid response for this PDU.

This method must check whether the buffer pointed by ptr is a valid response for this PDU. If it is valid, then it might want to propagate the call to the next PDU. Note that in some cases, such as ICMP Host Unreachable, there is no need to ask the next layer for matching.

Parameters

ptr	The pointer to the buffer.
total_sz	The size of the buffer.

Reimplemented in Tins::ICMPv6, Tins::DNS, Tins::DHCPv6, Tins::IP, Tins::TCP, Tins::ICMP, Tins::RadioTap, Tins::IPv6, Tins::ARP, Tins::BootP, Tins::Dot1Q, Tins::RawPDU, Tins::EthernetII, Tins::Dot3, Tins::UDP, Tins::PDUCacher< T >, and Tins::Loopback.

PDU& Tins::PDU::operator= ( PDU && rhs )

inline

Move assignment operator.

Parameters

rhs	The PDU to be moved.

PDU* Tins::PDU::parent_pdu ( ) const

inline

Getter for the parent PDU

Returns: The current parent PDU. Might be a null pointer.

virtual PDUType Tins::PDU::pdu_type ( ) const

pure virtual

Getter for the PDU's type.

Returns: Returns the PDUType corresponding to the PDU.

Implemented in Tins::Dot11ManagementFrame, Tins::ICMPv6, Tins::DHCPv6, Tins::DNS, Tins::RSNEAPOL, Tins::Dot11BlockAck, Tins::IP, Tins::Dot11ReAssocResponse, Tins::Dot11BlockAckRequest, Tins::TCP, Tins::Dot11ReAssocRequest, Tins::DHCP, Tins::Dot11, Tins::ICMP, Tins::Dot11Ack, Tins::RadioTap, Tins::Dot11EndCFAck, Tins::Dot11AssocResponse, Tins::RC4EAPOL, Tins::Dot11QoSData, Tins::IPv6, Tins::Dot11CFEnd, Tins::LLC, Tins::BootP, Tins::ARP, Tins::Dot11PSPoll, Tins::IPSecESP, Tins::Dot11Deauthentication, Tins::Dot11Data, Tins::Dot11AssocRequest, Tins::Dot11ProbeResponse, Tins::Dot11RTS, Tins::RawPDU, Tins::PPPoE, Tins::EthernetII, Tins::Dot3, Tins::STP, Tins::UDP, Tins::Dot11Beacon, Tins::EAPOL, Tins::SNAP, Tins::IPSecAH, Tins::MPLS, Tins::PDUCacher< T >, Tins::Dot11Authentication, Tins::Dot1Q, Tins::SLL, Tins::Dot11Disassoc, Tins::Loopback, Tins::Dot11ProbeRequest, and Tins::Dot11Control.

void Tins::PDU::prepare_for_serialize ( )

protectedvirtual

Prepares this PDU for serialization.

This method is called before the inner PDUs are serialized. It's useful in situations such as when serializing IP PDUs, which don't contain any link layer encapsulation, and therefore require to set the source IP address before the TCP/UDP checksum is calculated.

By default, this method does nothing

PDU * Tins::PDU::recv_response	(	PacketSender &	sender,
		const NetworkInterface &	iface
	)

virtual

Receives a matching response for this packet.

This method should act as a proxy for PacketSender::recv_lX methods.

Parameters

sender	The packet sender which will receive the packet.
iface	The interface in which to expect the response.

Reimplemented in Tins::IP, Tins::IPv6, Tins::EthernetII, Tins::Dot3, and Tins::PDUCacher< T >.

PDU * Tins::PDU::release_inner_pdu ( )

Releases the inner PDU.

This method makes this PDU to no longer own the inner PDU. The current inner PDU is returned, and is not destroyed. That means after calling this function, you are responsible for using operator delete on the returned pointer.

Use this method if you want to somehow re-use a PDU that is already owned by another PDU.

Returns: The current inner PDU. Might be 0.

template<typename T >

T& Tins::PDU::rfind_pdu ( PDUType type = T::pdu_flag )

inline

Finds and returns the first PDU that matches the given flag.

If the PDU is not found, a pdu_not_found exception is thrown.

See also: PDU::find_pdu

Parameters

flag	The flag which being searched.

template<typename T >

const T& Tins::PDU::rfind_pdu ( PDUType type = T::pdu_flag ) const

inline

Finds and returns the first PDU that matches the given flag.

Parameters

flag	The flag which being searched.

void Tins::PDU::send	(	PacketSender &	sender,
		const NetworkInterface &	iface
	)

virtual

Send the stack of PDUs through a PacketSender.

This method will be called only for the PDU on the bottom of the stack, therefore it should only implement this method if it can be sent.

PacketSender implements specific methods to send packets which start on every valid TCP/IP stack layer; this should only be a proxy for those methods.

If this PDU does not represent a link layer protocol, then the interface argument will be ignored.

Parameters

sender	The PacketSender which will send the packet.
iface	The network interface in which this packet will be sent.

Reimplemented in Tins::IP, Tins::Dot11, Tins::IPv6, Tins::RadioTap, Tins::EthernetII, Tins::Dot3, and Tins::PDUCacher< T >.

PDU::serialization_type Tins::PDU::serialize ( )

Serializes the whole chain of PDU's, including this one.

This allocates a std::vector of size size(), and fills it with the serialization this PDU, and all of the inner ones'.

Returns: serialization_type containing the serialization of the whole stack of PDUs.

void Tins::PDU::serialize	(	uint8_t *	buffer,
		uint32_t	total_sz
	)

protected

Serializes this PDU and propagates this action to child PDUs.

Parameters

buffer	The buffer in which to store this PDU's serialization.
total_sz	The total size of the buffer.

uint32_t Tins::PDU::size ( ) const

The whole chain of PDU's size, including this one.

Returns the sum of this and all children PDUs' size.

virtual uint32_t Tins::PDU::trailer_size ( ) const

inlinevirtual

Trailer's size.

Some protocols require a trailer(like Ethernet). This defaults to 0.

Reimplemented in Tins::ICMPv6, Tins::RadioTap, Tins::ICMP, Tins::EthernetII, and Tins::Dot1Q.

virtual void Tins::PDU::write_serialization	(	uint8_t *	buffer,
		uint32_t	total_sz
	)

protectedpure virtual

Serializes this TCP PDU.

Each PDU must override this method and implement it's own serialization.

Parameters

buffer	The buffer in which the PDU will be serialized.
total_sz	The size available in the buffer.

Implemented in Tins::BootP.

Member Data Documentation

const endian_type Tins::PDU::endianness = BE

static

The endianness used by this PDU. This can be overriden by subclasses.

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

/home/matias/Projects/libtins/code/include/tins/pdu.h
/home/matias/Projects/libtins/code/src/pdu.cpp

Classes

Public Types

Public Member Functions

Static Public Attributes

Protected Member Functions

Detailed Description

Member Typedef Documentation

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation