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// Copyright (C) 2022-2023 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 ITERATIVE_ALLOCATOR_H
#define ITERATIVE_ALLOCATOR_H
#include <dhcpsrv/allocator.h>
#include <dhcpsrv/iterative_allocation_state.h>
#include <dhcpsrv/lease.h>
#include <cstdint>
namespace isc {
namespace dhcp {
/// @brief Address/prefix allocator that iterates over all addresses.
///
/// This class implements an iterative algorithm that returns all addresses in
/// a pool iteratively, one after another. Once the last address is reached,
/// it starts allocating from the beginning of the first pool (i.e. it loops
/// over).
class IterativeAllocator : public Allocator {
public:
/// @brief Constructor.
///
/// @param type specifies the type of allocated leases.
/// @param subnet weak pointer to the subnet owning the allocator.
IterativeAllocator(Lease::Type type, const WeakSubnetPtr& subnet);
/// @brief Returns the allocator type string.
///
/// @return iterative string.
virtual std::string getType() const {
return ("iterative");
}
private:
/// @brief Returns the next address from the pools in the subnet.
///
/// Internal thread-unsafe implementation of the @c pickAddress.
///
/// @param client_classes list of classes client belongs to.
/// @param duid client DUID (ignored).
/// @param hint client hint (ignored).
///
/// @return next offered address.
virtual asiolink::IOAddress pickAddressInternal(const ClientClasses& client_classes,
const IdentifierBaseTypePtr& duid,
const asiolink::IOAddress& hint);
/// @brief Picks a delegated prefix.
///
/// Internal thread-unsafe implementation of the @c pickPrefix.
///
/// @param client_classes list of classes client belongs to.
/// @param pool the selected pool satisfying all required conditions.
/// @param duid Client's DUID.
/// @param prefix_length_match type which indicates the selection criteria
/// for the pools relative to the provided hint prefix length.
/// @param hint Client's hint.
/// @param hint_prefix_length the hint prefix length that the client
/// provided. The 0 value means that there is no hint and that any
/// pool will suffice.
///
/// @return the next prefix.
virtual asiolink::IOAddress pickPrefixInternal(const ClientClasses& client_classes,
Pool6Ptr& pool,
const IdentifierBaseTypePtr& duid,
PrefixLenMatchType prefix_length_match,
const asiolink::IOAddress& hint,
uint8_t hint_prefix_length);
/// @brief Convenience function returning subnet allocation state instance.
///
/// It creates a new subnet state instance and assigns it to the subnet
/// if it hasn't been initialized.
///
/// @return allocation state instance for the subnet.
SubnetIterativeAllocationStatePtr getSubnetState() const;
/// @brief Convenience function returning pool allocation state instance.
///
/// It creates a new pool state instance and assigns it to the pool
/// if it hasn't been initialized.
///
/// @param pool pool instance.
/// @return allocation state instance for the pool.
PoolIterativeAllocationStatePtr getPoolState(const PoolPtr& pool) const;
protected:
/// @brief Returns the next prefix.
///
/// This method works for IPv6 addresses only. It increases the
/// specified prefix by a given prefix_len. For example, 2001:db8::
/// increased by prefix length /32 will become 2001:db9::. This method
/// is used to iterate over IPv6 prefix pools
///
/// @param prefix prefix to be increased.
/// @param prefix_len length of the prefix to be increased.
///
/// @return next prefix.
static asiolink::IOAddress increasePrefix(const asiolink::IOAddress& prefix,
const uint8_t prefix_len);
/// @brief Returns the next address or prefix.
///
/// This method works for IPv4 addresses, IPv6 addresses and
/// IPv6 prefixes.
///
/// @param address address or prefix to be increased
/// @param prefix true when the previous argument is a prefix.
/// @param prefix_len length of the prefix.
///
/// @return result address or prefix
static asiolink::IOAddress increaseAddress(const asiolink::IOAddress& address,
bool prefix,
const uint8_t prefix_len);
};
} // namespace dhcp
} // end of namespace isc
#endif // ITERATIVE_ALLOCATOR_H
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