PathAttribute Class Reference

Inheritance diagram for PathAttribute:

List of all members.

Public Types
enum	Flags {   Optional = 0x80, Transitive = 0x40, Partial = 0x20, Extended = 0x10,   ValidFlags = 0xf0, NoFlags = 0 }
Public Member Functions
virtual PathAttribute *	clone () const =0
	Make a copy of the current attribute.
virtual bool	encode (uint8_t *buf, size_t &length, const BGPPeerData *peerdata) const =0
	encode a path attribute.
size_t	header_size () const
PathAttType	type () const
Flags	flags () const
void	set_partial ()
	Set the partial flag.
bool	operator< (const PathAttribute &him) const
	comparison operators are used to sort attributes.
bool	operator== (const PathAttribute &him) const
void	add_hash (MD5_CTX *context) const
	compute the hash for this object.
virtual string	str () const
	We need to encode an attribute to send to a peer.
void	pretty_print ()
bool	optional () const
bool	transitive () const
bool	partial () const
bool	extended () const
bool	well_known () const
Static Public Member Functions
static PathAttribute *	create (const uint8_t *d, uint16_t max_len, size_t &actual_length, const BGPPeerData *peerdata, uint32_t ip_version) throw (CorruptMessage)
	main routine to create a PathAttribute from incoming data.
Protected Member Functions
int	sorttype () const
	sorttype() is only used in sorting a path attribute list.
	PathAttribute (Flags f, PathAttType t)
	helper constructor used when creating an object from a derived class.
	PathAttribute (const uint8_t *d)
	basic constructor from data, assumes that the block has at least the required size.
uint8_t *	set_header (uint8_t *data, size_t payload_size, size_t &wire_size) const
	helper function to fill the header.
const uint8_t *	payload (const uint8_t *d)
Static Protected Member Functions
static size_t	length (const uint8_t *d)
	fetch the length from the header.
static size_t	total_tlv_length (const uint8_t *d)
	Total length including the header.
Protected Attributes
uint8_t	_flags
uint8_t	_type

---

Member Function Documentation

virtual PathAttribute* PathAttribute::clone

(

)

const [pure virtual]

Make a copy of the current attribute.

The derived class should use new to generate a copy of itself. The wire format representation will not be used by the caller.

Implemented in AnyAttribute, OriginAttribute, ASPathAttribute, AS4PathAttribute, NextHopAttribute< A >, MEDAttribute, LocalPrefAttribute, AtomicAggAttribute, AggregatorAttribute, AS4AggregatorAttribute, CommunityAttribute, OriginatorIDAttribute, ClusterListAttribute, MPReachNLRIAttribute< A >, MPUNReachNLRIAttribute< A >, and UnknownAttribute.

PathAttribute * PathAttribute::create	(	const uint8_t *	d,
		uint16_t	max_len,
		size_t &	actual_length,
		const BGPPeerData *	peerdata,
		uint32_t	ip_version
	)		throw (CorruptMessage) [static]

main routine to create a PathAttribute from incoming data.

Takes a chunk of memory of size l, returns an object of the appropriate type and actual_length is the number of bytes used from the packet. Throws an exception on error.

bool PathAttribute::encode	(	uint8_t *	buf,
		size_t &	wire_size,
		const BGPPeerData *	peerdata
	)		const [pure virtual]

encode a path attribute.

In a sane world, we'd use a virtual function for this. But we store so many path attributes that we can't afford the overhead of a virtual function table for them, so we have to do this the hard way

XXX THE ABOVE IS NO LONGER THE CASE. WE SHOULD REWRITE THIS TO USE VIRTUAL FUNCTIONS

Implemented in AnyAttribute, OriginAttribute, ASPathAttribute, AS4PathAttribute, NextHopAttribute< A >, MEDAttribute, LocalPrefAttribute, AtomicAggAttribute, AggregatorAttribute, AS4AggregatorAttribute, CommunityAttribute, OriginatorIDAttribute, ClusterListAttribute, MPReachNLRIAttribute< A >, MPUNReachNLRIAttribute< A >, UnknownAttribute, MPReachNLRIAttribute< A >, MPReachNLRIAttribute< A >, MPUNReachNLRIAttribute< A >, and MPUNReachNLRIAttribute< A >.

Flags PathAttribute::flags

(

)

const [inline]

Returns:

the flags for the attribute

size_t PathAttribute::header_size

(

)

const [inline]

Returns:

the size of the header.

static size_t PathAttribute::length

(

const uint8_t *

d

)

[inline, static, protected]

fetch the length from the header.

Assume the header is there.

bool PathAttribute::operator<

(

const PathAttribute &

him

)

const

comparison operators are used to sort attributes.

Right now the sort order is based on the type, size() and payload representation.

uint8_t * PathAttribute::set_header	(	uint8_t *	data,
		size_t	payload_size,
		size_t &	wire_size
	)		const [protected]

helper function to fill the header.

Needs _flags and _type properly initialized. Writes into data buffer, and returns pointer to first byte of buffer after the header.

int PathAttribute::sorttype

(

)

const [inline, protected]

sorttype() is only used in sorting a path attribute list.

It is different from PathAttType because we want to sort the path attribute list on NextHop for less expensive processing when the IGP information for a nexthop changes. So we give priority to NEXT_HOP and keep other values unchanged.

string PathAttribute::str

(

)

const [virtual]

We need to encode an attribute to send to a peer.

However we only have the canonically encoded byte stream data for it. Sometimes that is fine, and we should just send that; sometimes we need to decode and re-encode for this specific peer.

Reimplemented in OriginAttribute, ASPathAttribute, AS4PathAttribute, NextHopAttribute< A >, MEDAttribute, LocalPrefAttribute, AtomicAggAttribute, AggregatorAttribute, AS4AggregatorAttribute, CommunityAttribute, OriginatorIDAttribute, ClusterListAttribute, MPReachNLRIAttribute< A >, MPUNReachNLRIAttribute< A >, and UnknownAttribute.

static size_t PathAttribute::total_tlv_length

(

const uint8_t *

d

)

[inline, static, protected]

Total length including the header.

Used to send the whole TLV back when an error has been detected.

PathAttType PathAttribute::type

(

)

const [inline]

Returns:

the type of the attribute

---

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

• /home/greearb/git/xorp.ct.github/xorp/bgp/path_attribute.hh
• /home/greearb/git/xorp.ct.github/xorp/bgp/path_attribute.cc