Kea 2.5.9
isc::dhcp::FreeLeaseQueueAllocator Class Reference

An allocator maintaining a queue of free leases. More...

#include <flq_allocator.h>

+ Inheritance diagram for isc::dhcp::FreeLeaseQueueAllocator:

Public Member Functions

 FreeLeaseQueueAllocator (Lease::Type type, const WeakSubnetPtr &subnet)
virtual std::string getType () const
 Returns the allocator type string.
- Public Member Functions inherited from isc::dhcp::Allocator
 Allocator (Lease::Type type, const WeakSubnetPtr &subnet)
virtual ~Allocator ()
 Virtual destructor.
virtual std::string getType () const =0
 Returns allocator type string.
void initAfterConfigure ()
 Performs allocator initialization after server's reconfiguration.
virtual isc::asiolink::IOAddress pickAddress (const ClientClasses &client_classes, const IdentifierBaseTypePtr &duid, const asiolink::IOAddress &hint)
 Picks an address.
virtual isc::asiolink::IOAddress pickPrefix (const ClientClasses &client_classes, Pool6Ptr &pool, const IdentifierBaseTypePtr &duid, PrefixLenMatchType prefix_length_match, const asiolink::IOAddress &hint, uint8_t hint_prefix_length)
 Picks a delegated prefix.

Additional Inherited Members

- Public Types inherited from isc::dhcp::Allocator
 Type of preferred PD-pool prefix length selection criteria. More...
- Static Public Member Functions inherited from isc::dhcp::Allocator
static bool isValidPrefixPool (Allocator::PrefixLenMatchType prefix_length_match, PoolPtr pool, uint8_t hint_prefix_length)
 Check if the pool matches the selection criteria relative to the provided hint prefix length.
virtual void initAfterConfigureInternal ()
 Allocator-specific initialization function.
- Protected Attributes inherited from isc::dhcp::Allocator
bool inited_
 Indicates if the allocator has been initialized.
std::mutex mutex_
 The mutex to protect the allocated lease.
Lease::Type pool_type_
 Defines pool type allocation.
WeakSubnetPtr subnet_
 Weak pointer to the subnet owning the allocator.
SubnetID subnet_id_
 ID of a subnet to which the allocator belongs.

Detailed Description

An allocator maintaining a queue of free leases.

This allocator populates the queue of free leases during the initialization. It also installs the callbacks in the LeaseMgr, to track the subsequent lease changes. It allows for maintaining the running queue of free leases.

The allocator offers the leases from the queue, minimizing the number of the allocation engine's attempts to check if some other client is using the offered lease. Ideally, only one check should suffice. However, when several servers share a lease database, the collisions may occur because the servers don't observe each others' allocations.

This allocator should only be used for reasonably small pools due to the overhead to populate the free leases. A reasonably small pool is an IPv4 pool (including /8) and the prefix delegation pools with similar capacity. This allocator is not suitable for a typical IPv6 address pool (e.g., /64). An attempt to populate free leases for such a giant pool would freeze the server and likely exhaust its memory.

Free leases are populated in a random order.

Definition at line 38 of file flq_allocator.h.

Constructor & Destructor Documentation

◆ FreeLeaseQueueAllocator()

isc::dhcp::FreeLeaseQueueAllocator::FreeLeaseQueueAllocator ( Lease::Type  type,
const WeakSubnetPtr subnet 


typespecifies the type of allocated leases.
subnetweak pointer to the subnet owning the allocator.

Definition at line 31 of file

Member Function Documentation

◆ getType()

virtual std::string isc::dhcp::FreeLeaseQueueAllocator::getType ( ) const

Returns the allocator type string.

flq string.

Implements isc::dhcp::Allocator.

Definition at line 50 of file flq_allocator.h.

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