bm::PHV Class Reference

Public Types
using	header_name_iterator = HeaderNamesMap::iterator
using	const_header_name_iterator = HeaderNamesMap::const_iterator
using	header_iterator = std::vector< Header >::iterator
	Used to iterate over headers in ascending id order. More...
using	const_header_iterator = std::vector< Header >::const_iterator
	Used to iterate over headers in ascending id order. More...

Public Member Functions
Header &	get_header (header_id_t header_index)
	Access the Header with id header_index, with no bound checking. More...
const Header &	get_header (header_id_t header_index) const
	Access the Header with id header_index, with no bound checking. More...
Header &	get_header (const std::string &header_name)
const Header &	get_header (const std::string &header_name) const
bool	has_header (const std::string &header_name) const
	Returns true if there exists a Header with name header_name in this PHV. More...
Field &	get_field (header_id_t header_index, int field_offset)
const Field &	get_field (header_id_t header_index, int field_offset) const
Field &	get_field (const std::string &field_name)
const Field &	get_field (const std::string &field_name) const
bool	has_field (const std::string &field_name) const
HeaderStack &	get_header_stack (header_stack_id_t header_stack_index)
const HeaderStack &	get_header_stack (header_stack_id_t header_stack_index) const
HeaderUnion &	get_header_union (header_union_id_t header_union_index)
const HeaderUnion &	get_header_union (header_union_id_t header_union_index) const
HeaderUnionStack &	get_header_union_stack (header_union_stack_id_t header_union_stack_index)
const HeaderUnionStack &	get_header_union_stack (header_union_stack_id_t header_union_stack_index) const
void	reset ()
	Mark all Header instances in the PHV as invalid. More...
void	reset_header_stacks ()
void	reset_metadata ()
void	reset_headers ()
	Reset all header fields to 0. More...
void	set_written_to (bool written_to_value)
	PHV (const PHV &other)=delete
	Deleted copy constructor. More...
PHV &	operator= (const PHV &other)=delete
	Deleted copy assignment operator. More...
	PHV (PHV &&other)=default
	Default move constructor. More...
PHV &	operator= (PHV &&other)=default
	Default move assignment operator. More...
void	copy_headers (const PHV &src)
header_name_iterator	header_name_begin ()
const_header_name_iterator	header_name_begin () const
header_name_iterator	header_name_end ()
const_header_name_iterator	header_name_end () const
header_iterator	header_begin ()
const_header_iterator	header_begin () const
header_iterator	header_end ()
	Returns an iterator to the last element in the PHV. See header_begin(). More...
const_header_iterator	header_end () const
	Returns an iterator to the last element in the PHV. See header_begin(). More...
size_t	num_headers () const
	Returns the number of headers included in the PHV. More...
const std::string	get_field_name (header_id_t header_index, int field_offset) const

Detailed Description

Each Packet instance owns a PHV instance, used to store all the data extracted from the packet by parsing. It essentially consists of a vector of Header instances, each one of these Header instance itself consisting of a vector of Field instances. The PHV also owns the HeaderStack instances for the packet.

Because PHV objects are expensive to construct, we maintain a pool of them. Every time a new Packet is constructed, we retrieve one PHV from the pool (construct a new one if the pool is empty). When the Packet is destroyed, we release its PHV to the pool. Because the PHV depends on the P4 Context, there is actually one PHV pool per Contex. If the Context of a Packet changes, its current PHV is released to the old pool and a new PHV is obtained from the new pool. Because we use a pool system, a Packet may receive a PHV which still contains "state" (e.g. field values) from its previous Packet owner. This is why we expose methods like reset(), reset_header_stacks() and reset_metadata().

Member Typedef Documentation

const_header_iterator

using bm::PHV::const_header_iterator = std::vector<Header>::const_iterator

Used to iterate over headers in ascending id order.

const_header_name_iterator

using bm::PHV::const_header_name_iterator = HeaderNamesMap::const_iterator

Used to iterate over headers and access their names. The order may be different from the header id order.

header_iterator

using bm::PHV::header_iterator = std::vector<Header>::iterator

Used to iterate over headers in ascending id order.

header_name_iterator

using bm::PHV::header_name_iterator = HeaderNamesMap::iterator

Used to iterate over headers and access their names. The order may be different from the header id order.

Constructor & Destructor Documentation

PHV() [1/2]

bm::PHV::PHV ( const PHV &  other )

delete

Deleted copy constructor.

PHV() [2/2]

bm::PHV::PHV ( PHV &&  other )

default

Default move constructor.

Member Function Documentation

copy_headers()

void bm::PHV::copy_headers

(

const PHV &

src

)

Copy the headers of src PHV to this PHV. The two PHV instances need to belong to the same Context. Every header:

• is marked valid iff the corresponding src header is valid
• is marked as metadata iff the corresponding src header is metadata
• receives the same field values as the corresponding src header iff it is a valid packet header or a metadata header

get_field() [1/4]

Field& bm::PHV::get_field ( const std::string &  field_name )

inline

Access the Field with name field_name. If field_name does not match any known fields, an std::out_of_range exception will be thrown. field_name must follow the "hdr.f" format.

get_field() [2/4]

const Field& bm::PHV::get_field ( const std::string &  field_name ) const

inline

Access the Field with name field_name. If field_name does not match any known fields, an std::out_of_range exception will be thrown. field_name must follow the "hdr.f" format.

get_field() [3/4]

Field& bm::PHV::get_field ( header_id_t  header_index, int  field_offset  )

inline

Access the Field at offset field_offset in the Header with id header_index. See PHV::get_header(header_id_t header_index) and Header::get_field(int field_offset) for more information.

get_field() [4/4]

const Field& bm::PHV::get_field ( header_id_t  header_index, int  field_offset  ) const

inline

Access the Field at offset field_offset in the Header with id header_index. See PHV::get_header(header_id_t header_index) and Header::get_field(int field_offset) for more information.

get_field_name()

const std::string bm::PHV::get_field_name	(	header_id_t	header_index,
		int	field_offset
	)		const

Returns the full name of the field as a new string. The name is of the form <hdr_name>.<f_name>.

get_header() [1/4]

Header& bm::PHV::get_header ( const std::string &  header_name )

inline

Access the Header with name header_name. If header_name does not match any known headers, an std::out_of_range exception will be thrown.

get_header() [2/4]

const Header& bm::PHV::get_header ( const std::string &  header_name ) const

inline

Access the Header with name header_name. If header_name does not match any known headers, an std::out_of_range exception will be thrown.

get_header() [3/4]

Header& bm::PHV::get_header ( header_id_t  header_index )

inline

Access the Header with id header_index, with no bound checking.

get_header() [4/4]

const Header& bm::PHV::get_header ( header_id_t  header_index ) const

inline

Access the Header with id header_index, with no bound checking.

get_header_stack() [1/2]

HeaderStack& bm::PHV::get_header_stack ( header_stack_id_t  header_stack_index )

inline

Access the HeaderStack with id header_stack_index, with no bound checking.

get_header_stack() [2/2]

const HeaderStack& bm::PHV::get_header_stack ( header_stack_id_t  header_stack_index ) const

inline

Access the HeaderStack with id header_stack_index, with no bound checking.

get_header_union() [1/2]

HeaderUnion& bm::PHV::get_header_union ( header_union_id_t  header_union_index )

inline

Access the HeaderUnion with id header_union_index, with no bound checking.

get_header_union() [2/2]

const HeaderUnion& bm::PHV::get_header_union ( header_union_id_t  header_union_index ) const

inline

Access the HeaderUnion with id header_union_index, with no bound checking.

get_header_union_stack() [1/2]

HeaderUnionStack& bm::PHV::get_header_union_stack ( header_union_stack_id_t  header_union_stack_index )

inline

Access the HeaderUnionStack with id header_union_stack_index, with no bound checking.

get_header_union_stack() [2/2]

const HeaderUnionStack& bm::PHV::get_header_union_stack ( header_union_stack_id_t  header_union_stack_index ) const

inline

has_field()

bool bm::PHV::has_field ( const std::string &  field_name ) const

inline

Returns true if there exists a Field with name field_name in this PHV. field_name must follow the "hdr.f" format.

has_header()

bool bm::PHV::has_header ( const std::string &  header_name ) const

inline

Returns true if there exists a Header with name header_name in this PHV.

header_begin() [1/2]

header_iterator bm::PHV::header_begin ( )

inline

Returns an iterator to the first header in the PHV.

auto it = phv.header_begin();
const Header &header = *it;

header_begin() [2/2]

const_header_iterator bm::PHV::header_begin ( ) const

inline

Returns an iterator to the first header in the PHV.

auto it = phv.header_begin();
const Header &header = *it;

header_end() [1/2]

header_iterator bm::PHV::header_end ( )

inline

Returns an iterator to the last element in the PHV. See header_begin().

header_end() [2/2]

const_header_iterator bm::PHV::header_end ( ) const

inline

Returns an iterator to the last element in the PHV. See header_begin().

header_name_begin() [1/2]

header_name_iterator bm::PHV::header_name_begin ( )

inline

Returns an iterator to the first header in the "name -> header reference" map maintained by the PHV.

auto it = phv.header_name_begin();
const std::string &header = it->first;
const Header &header = it->second;

header_name_begin() [2/2]

const_header_name_iterator bm::PHV::header_name_begin ( ) const

inline

Returns an iterator to the first header in the "name -> header reference" map maintained by the PHV.

auto it = phv.header_name_begin();
const std::string &header = it->first;
const Header &header = it->second;

header_name_end() [1/2]

header_name_iterator bm::PHV::header_name_end ( )

inline

Returns an iterator to the last element in the "name -> header reference" map maintained by the PHV. See header_name_begin() for more information.

header_name_end() [2/2]

const_header_name_iterator bm::PHV::header_name_end ( ) const

inline

Returns an iterator to the last element in the "name -> header reference" map maintained by the PHV. See header_name_begin() for more information.

num_headers()

size_t bm::PHV::num_headers ( ) const

inline

Returns the number of headers included in the PHV.

operator=() [1/2]

PHV& bm::PHV::operator= ( const PHV &  other )

delete

Deleted copy assignment operator.

operator=() [2/2]

PHV& bm::PHV::operator= ( PHV &&  other )

default

Default move assignment operator.

reset()

void bm::PHV::reset

(

)

Mark all Header instances in the PHV as invalid.

reset_header_stacks()

void bm::PHV::reset_header_stacks

(

)

Reset the state (i.e. make them empty) of all HeaderStack instances in the PHV.

reset_headers()

void bm::PHV::reset_headers

(

)

Reset all header fields to 0.

reset_metadata()

void bm::PHV::reset_metadata

(

)

Reset all metadata fields to 0. If your target assumes that metadata fields are zero-initialized for every incoming packet, you will need to call this on the PHV member of every new Packet you create.

set_written_to()

void bm::PHV::set_written_to

(

bool

written_to_value

)

Set the written_to flag maintained by each field. This flag can be queried at any time by the target, using the Field interface, and can be used to check whether the field has been modified since written_to was last set to false.

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

• include/bm/bm_sim/phv.h