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.

virtual unsigned	evaluate (Pkt &pkt, ValueStack &values)
	Evaluates the values of the option.

uint16_t	getCode () const
	Returns option-code.

RepresentationType	getRepresentation () const
	Returns representation-type.

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

virtual unsigned	getLabel () const
	Return the label of this token.

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

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

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

RepresentationType	representation_type_
	Representation type.

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.

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 403 of file token.h.

Member Enumeration Documentation

◆ RepresentationType

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 413 of file token.h.

Constructor & Destructor Documentation

◆ TokenOption()

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 426 of file token.h.

Member Function Documentation

◆ evaluate()

unsigned 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 "")

Returns: 0 which means evaluate next token if any.

Implements isc::dhcp::Token.

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

Definition at line 402 of file token.cc.

References isc::dhcp::EVAL_DBG_STACK, isc::dhcp::EVAL_DEBUG_OPTION, isc::dhcp::eval_logger, EXISTS, isc::dhcp::Pkt::getLabel(), getOption(), HEXADECIMAL, LOG_DEBUG, option_code_, representation_type_, and TEXTUAL.

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

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◆ getCode()

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 446 of file token.h.

References option_code_.

◆ getOption()

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

pkt	the option will be retrieved from here

Returns: option instance (or NULL if not found)

Reimplemented in isc::dhcp::TokenRelay4Option, isc::dhcp::TokenRelay6Option, and isc::dhcp::TokenVendor.

Definition at line 397 of file token.cc.

References isc::dhcp::Pkt::getOption(), and option_code_.

Referenced by evaluate(), and isc::dhcp::TokenSubOption::evaluate().

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◆ getRepresentation()

RepresentationType isc::dhcp::TokenOption::getRepresentation ( ) const

inline

Returns representation-type.

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

Returns: representation-type of the option this token expects to use.

Definition at line 456 of file token.h.

References representation_type_.

◆ pushFailure()

std::string TokenOption::pushFailure ( ValueStack & values )

protectedvirtual

Auxiliary method that puts string representing a failure.

Depending on the representation type, this is either "" or "false".

Parameters

values a string representing failure will be pushed here.

Returns: value pushed

Definition at line 444 of file token.cc.

References EXISTS, and representation_type_.

Referenced by isc::dhcp::TokenVendor::evaluate(), and isc::dhcp::TokenVendorClass::evaluate().

Member Data Documentation

◆ option_code_

uint16_t isc::dhcp::TokenOption::option_code_

protected

Code of the option to be extracted.

Definition at line 480 of file token.h.

Referenced by evaluate(), isc::dhcp::TokenSubOption::evaluate(), getCode(), getOption(), isc::dhcp::TokenRelay4Option::getOption(), isc::dhcp::TokenRelay6Option::getOption(), and isc::dhcp::TokenVendor::getOption().

◆ representation_type_

RepresentationType isc::dhcp::TokenOption::representation_type_

protected

Representation type.

Definition at line 481 of file token.h.

Referenced by isc::dhcp::TokenVendor::TokenVendor(), evaluate(), isc::dhcp::TokenSubOption::evaluate(), getRepresentation(), and pushFailure().

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

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ RepresentationType

Constructor & Destructor Documentation

◆ TokenOption()

Member Function Documentation

◆ evaluate()

◆ getCode()

◆ getOption()

◆ getRepresentation()

◆ pushFailure()

Member Data Documentation

◆ option_code_

◆ representation_type_