Base class for classes which need to be associated with a CalloutHandle object. More...

#include <callout_handle_associate.h>

Inheritance diagram for isc::hooks::CalloutHandleAssociate:

Public Member Functions
	CalloutHandleAssociate ()
	Constructor.

CalloutHandlePtr	getCalloutHandle ()
	Returns callout handle.

void	resetCalloutHandle ()
	Reset callout handle.

Protected Attributes
CalloutHandlePtr	callout_handle_
	Callout handle stored.

Detailed Description

Base class for classes which need to be associated with a CalloutHandle object.

The CalloutHandle is an object used to pass various parameters between Kea and the callouts. The Kea servers usually invoke multiple different callouts for a single packet such as DHCP packet, control command etc. Therefore, it is required to associate this packet with an instance of the callout handle, so this instance can be used for all callouts invoked for this packet.

Previously this association was made by the CalloutHandleStore class. However, with the introduction of parallel processing of packets (DHCP packets parking) it became awkward to use. Attempts to extend this class to hold a map of associations failed because of no easy way to garbage collect unused handles.

The easiest way to deal with this is to provide ownership of the CalloutHandle to the object with which it is associated. The class of this object needs to derive from this class. When the object (e.g. DHCP packet) goes out of scope and is destroyed this instance is destroyed as well.

Definition at line 37 of file callout_handle_associate.h.