Current File : //backups/router/usr/local/include/kea/dhcpsrv/memfile_lease_limits.h
// Copyright (C) 2022 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef MEMFILE_LEASE_LIMITS_H
#define MEMFILE_LEASE_LIMITS_H
#include <asiolink/io_address.h>
#include <cc/data.h>
#include <dhcp/classify.h>
#include <dhcpsrv/lease.h>
#include <dhcpsrv/subnet_id.h>
#include <stats/stats_mgr.h>
#include <unordered_map>
namespace isc {
namespace dhcp {
/// @brief Container that maintains counts of leases per class and lease type.
///
/// For methods on this class which accept the lease type as a parameter the value
/// is one of the following Lease::TYPE_V4, Lease::TYPE_NA, Lease::TYPE_PD. Kea
/// does not support Lease::TYPE_TA leases and this value is treated as invalid.
/// Note that for simplicity and performance an instance of container is assumed
/// to be used either only for DHCPv4 processing or DHCPv6 processing but not both
/// concurrently.
class ClassLeaseCounter {
public:
/// @brief Defines ClassCountMap as an unordered map of counts.
typedef std::unordered_map<ClientClass, size_t> ClassCountMap;
/// @brief Constructor
ClassLeaseCounter() = default;
/// @brief Destructor
~ClassLeaseCounter() = default;
/// @brief Fetches the lease count for the given class and lease type.
///
/// @param client_class class for which the count is desired
/// @param ltype lease type for which the count is desired, defaults to
/// Lease::TYPE_V4
///
/// @return Number of leases for the class and lease type. If there is no
/// entry found for the class and lease type, a value of zero is returned.
size_t getClassCount(const ClientClass& client_class,
const Lease::Type& ltype = Lease::TYPE_V4) const;
/// @brief Sets the lease count for the given class and lease type to a value.
///
/// @param client_class class for which the count is desired
/// @param count new count value for the class and lease type.
/// @param ltype lease type for which the count is desired, defaults
/// to Lease::TYPE_V4
void setClassCount(const ClientClass& client_class, size_t count,
const Lease::Type& ltype = Lease::TYPE_V4);
/// @brief Adjust the count for a given class and lease type by a signed offset.
///
/// If no entry exists in container for the class and type, a new one is created.
///
/// @param client_class client class to adjust
/// @param offset signed amount to add to the current count
/// @param ltype lease type for which the count is desired, defaults
/// to Lease::TYPE_V4
void adjustClassCount(const ClientClass& client_class, int offset,
const Lease::Type& ltype = Lease::TYPE_V4);
/// @brief Adjust the count for a list of classes for a lease type by
/// a signed offset.
///
/// @param classes list of classes to adjust
/// @param offset signed amount to add the current count
/// @param ltype lease type for which the count is desired, defaults
/// to Lease::TYPE_V4
void adjustClassCounts(data::ConstElementPtr classes, int offset,
const Lease::Type& ltype = Lease::TYPE_V4);
/// @brief Increment the counts for all of a lease's classes by one
///
/// Function is intended to be whenever a new lease is being added.
///
/// @param lease lease whose classes are to be incremented
void addLease(LeasePtr lease);
/// @brief Adjust class lease counts given a new and old version of a lease
///
/// Function is intended to be used whenever an existing lease is being updated.
/// If, upon comparison of the two leases, either the lease states or the class
/// lists are different then:
///
/// -# Decrement the counts for the old class list if the old lease state
/// is Lease::STATE_DEFAULT
/// -# Increment the counts for the new class list if the new lease state
/// is Lease::STATE_DEFAULT
///
/// @param new_lease new version of the lease
/// @param old_lease old version of the lease
void updateLease(LeasePtr new_lease, LeasePtr old_lease);
/// @brief Decrement the counts for all of a lease's classes by one
///
/// Function is intended to be whenever an existing lease is being deleted.
///
/// @param lease lease whose classes are to be decremented
void removeLease(LeasePtr lease);
/// @brief Remove all entries.
void clear() {
addresses_by_class_.clear();
pds_by_class_.clear();
}
/// @brief Get the number of entries for a given lease type
///
/// @param ltype type of lease for which the number of entries is desired,
/// defaults to Lease::TYPE_V4
///
/// @return Number of entries for the lease type
size_t size(const Lease::Type& ltype = Lease::TYPE_V4) const {
return (getConstCountMap(ltype).size());
}
/// @brief Fetches the list of classes from the lease's user-context
///
/// @param lease lease from which to fetch classes
/// @return ElementPtr to an Element::List containing the client classes or an
/// empty List.
static data::ConstElementPtr getLeaseClientClasses(LeasePtr lease);
private:
/// @brief Fetches the map used to count the given lease type.
///
/// @param ltype type of lease of for which the map is desired,
/// defaults to Lease::TYPE_V4
///
/// @return Reference to the map for the lease type
ClassCountMap& getCountMap(const Lease::Type& ltype = Lease::TYPE_V4) {
return (ltype == Lease::TYPE_PD ? pds_by_class_ : addresses_by_class_);
}
const ClassCountMap& getConstCountMap(const Lease::Type& ltype = Lease::TYPE_V4) const {
return (ltype == Lease::TYPE_PD ? pds_by_class_ : addresses_by_class_);
}
/// @brief Contains counts for classes for addresses. This map is used
/// to house either Lease::TYPE_V4 when used for V4 or Lease::TYPE_NA
/// when used for V6.
ClassCountMap addresses_by_class_;
/// @brief Contains counts for classes for Lease::TYPE_PD. Applicable
/// only for V6 use.
ClassCountMap pds_by_class_;
};
} // namespace dhcp
} // namespace isc
#endif // MEMFILE_LEASE_LIMITS_H
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