Token that represents a value of an option. More...

#include <token.h>

Inheritance diagram for isc::dhcp::TokenOption:

Public Types
enum	RepresentationType { TEXTUAL, HEXADECIMAL, EXISTS }
	Token representation type. More...

Public Member Functions
	TokenOption (const uint16_t option_code, const RepresentationType &rep_type)
	Constructor that takes an option code as a parameter. More...

void	evaluate (Pkt &pkt, ValueStack &values)
	Evaluates the values of the option. More...

uint16_t	getCode () const
	Returns option-code. More...

RepresentationType	getRepresentation () const
	Returns representation-type. More...

Public Member Functions inherited from isc::dhcp::Token
virtual	~Token ()
	Virtual destructor. More...

Protected Member Functions
virtual OptionPtr	getOption (Pkt &pkt)
	Attempts to retrieve an option. More...

virtual std::string	pushFailure (ValueStack &values)
	Auxiliary method that puts string representing a failure. More...

Protected Attributes
uint16_t	option_code_
	Code of the option to be extracted. More...

RepresentationType	representation_type_
	Representation type. More...

Additional Inherited Members
Static Public Member Functions inherited from isc::dhcp::Token
static bool	toBool (std::string value)
	Coverts a (string) value to a boolean. More...

Detailed Description

Token that represents a value of an option.

This represents a reference to a given option, e.g. in the expression option[vendor-class].text == "MSFT", it represents option[vendor-class].text

During the evaluation it tries to extract the value of the specified option. If the option is not found, an empty string ("") is returned (or "false" when the representation is EXISTS).

Definition at line 344 of file token.h.

Member Enumeration Documentation

enum isc::dhcp::TokenOption::RepresentationType

Token representation type.

There are many possible ways in which option can be presented. Currently the textual, hexadecimal and exists representations are supported. The type of representation is specified in the constructor and it affects the value generated by the TokenOption::evaluate function.

Enumerator
TEXTUAL
HEXADECIMAL
EXISTS

Definition at line 354 of file token.h.

Constructor & Destructor Documentation

isc::dhcp::TokenOption::TokenOption	(	const uint16_t	option_code,
		const RepresentationType &	rep_type
	)

inline

Constructor that takes an option code as a parameter.

Note: There is no constructor that takes option_name, as it would introduce complex dependency of the libkea-eval on libdhcpsrv.

Parameters

option_code	code of the option to be represented.
rep_type	Token representation type.

Definition at line 367 of file token.h.

Member Function Documentation

void TokenOption::evaluate	(	Pkt &	pkt,
		ValueStack &	values
	)

virtual

Evaluates the values of the option.

This token represents a value of the option, so this method attempts to extract the option from the packet and put its value on the stack. If the option is not there, an empty string ("") is put on the stack.

Parameters

pkt	specified option will be extracted from this packet (if present)
values	value of the option will be pushed here (or "")

Implements isc::dhcp::Token.

Reimplemented in isc::dhcp::TokenSubOption, isc::dhcp::TokenVendorClass, and isc::dhcp::TokenVendor.

Definition at line 329 of file token.cc.

References isc::dhcp::EVAL_DBG_STACK, isc::dhcp::EVAL_DEBUG_OPTION, isc::dhcp::eval_logger, EXISTS, getOption(), HEXADECIMAL, LOG_DEBUG, option_code_, representation_type_, TEXTUAL, and isc::util::encode::toHex().

Referenced by isc::dhcp::TokenVendor::evaluate().

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uint16_t isc::dhcp::TokenOption::getCode ( ) const

inline

Returns option-code.

This method is used in testing to determine if the parser had instantiated TokenOption with correct parameters.

Returns: option-code of the option this token expects to extract.

Definition at line 386 of file token.h.

References option_code_.

OptionPtr TokenOption::getOption ( Pkt & pkt )

protectedvirtual

Attempts to retrieve an option.

For this class it simply attempts to retrieve the option from the packet, but there may be derived classes that would attempt to extract it from other places (e.g. relay option, or as a suboption of other specific option).

Parameters