[#969] Random allocation state added

1 files changed, 74 insertions, 0 deletions

diff --git a/src/lib/dhcpsrv/random_allocation_state.h b/src/lib/dhcpsrv/random_allocation_state.h
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+++ b/src/lib/dhcpsrv/random_allocation_state.h
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+// 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 RANDOM_ALLOCATION_STATE_H
+#define RANDOM_ALLOCATION_STATE_H
+
+#include <dhcpsrv/allocation_state.h>
+#include <dhcpsrv/ip_range_permutation.h>
+#include <dhcpsrv/pool.h>
+#include <boost/shared_ptr.hpp>
+#include <cstdint>
+
+namespace isc {
+namespace dhcp {
+
+/// @brief Forward declaration of the @c PoolRandomAllocationState.
+class PoolRandomAllocationState;
+
+/// @brief Type of the pointer to the @c PoolRandomAllocationState.
+typedef boost::shared_ptr<PoolRandomAllocationState> PoolRandomAllocationStatePtr;
+
+/// @brief Pool allocation state used by the random allocator.
+///
+/// It extends the base class with the mechanism that maintains
+/// an address or delegated prefix pool permutation. The
+/// permutation serves random, non-repeating leases.
+class PoolRandomAllocationState : public AllocationState {
+public:
+
+    /// @brief Factory function creating the state instance from pool.
+    ///
+    /// @param pool instance of the pool for which the allocation state
+    /// should be instantiated.
+    /// @return new allocation state instance.
+    static PoolRandomAllocationStatePtr create(const PoolPtr& pool);
+
+    /// @brief Constructor from an IP address pool.
+    ///
+    /// @param first first address in the pool.
+    /// @param last last address in the pool.
+    PoolRandomAllocationState(const asiolink::IOAddress& first,
+                              const asiolink::IOAddress& last);
+
+    /// @brief Constructor from a delegated prefix pool.
+    ///
+    /// @param first first address in the pool.
+    /// @param last last prefix in the pool.
+    /// @param delegated delegated prefix length.
+    PoolRandomAllocationState(const asiolink::IOAddress& first,
+                              const asiolink::IOAddress& last,
+                              const uint8_t delegated);
+
+    /// @brief Returns a pointer to the permutation of addresses
+    /// or delegated prefixes.
+    ///
+    /// @return permutation instance.
+    IPRangePermutationPtr getPermutation() const {
+        return (permutation_);
+    }
+
+private:
+
+    /// @brief Permutation instance for the pool.
+    IPRangePermutationPtr permutation_;
+};
+
+
+} // end of isc::dhcp namespace
+} // end of isc namespace
+
+#endif // RANDOM_ALLOCATION_STATE_H