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+// Copyright (C) 2014-2021 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 HOST_MGR_H
+#define HOST_MGR_H
+
+#include <asiolink/io_service.h>
+#include <database/database_connection.h>
+#include <dhcpsrv/base_host_data_source.h>
+#include <dhcpsrv/cache_host_data_source.h>
+#include <dhcpsrv/host.h>
+#include <dhcpsrv/subnet_id.h>
+#include <boost/noncopyable.hpp>
+#include <boost/scoped_ptr.hpp>
+#include <string>
+
+namespace isc {
+namespace dhcp {
+
+/// @brief Host Manager.
+///
+/// This is a singleton class which provides access to multiple sources of
+/// information about static host reservations. These sources are also referred
+/// to as host data sources. Each source derives (directly or indirectly) from
+/// the @c BaseHostDataSource.
+///
+/// The @c HostMgr is a central point for providing information about the host
+/// reservations. Internally, it relays the queries (calls to the appropriate
+/// methods declared in the @c BaseHostDataSource) to the data sources it is
+/// connected to. The @c HostMgr is always connected to the server's
+/// configuration, accessible through the @c CfgHosts object in the @c CfgMgr.
+/// The @c CfgHosts object holds all reservations specified in the DHCP server
+/// configuration file. If a particular reservation is not found in the
+/// @c CfgHosts object, the @c HostMgr will try to find it using alternate
+/// host data storages. An alternate host data storage is usually a database
+/// (e.g. SQL database), accessible through a dedicated host data source
+/// object (a.k.a. database backend). This datasource is responsible for
+/// managing the connection with the database and forming appropriate queries
+/// to retrieve (or update) the information about the reservations.
+///
+/// The use of alternate host data sources is optional and usually requires
+/// additional configuration to be specified by the server administrator.
+/// For example, for the SQL database the user's credentials, database address,
+/// and database name are required. The @c HostMgr passes these parameters
+/// to an appropriate datasource which is responsible for opening a connection
+/// and maintaining it.
+///
+/// It is possible to switch to different alternate data sources or disable
+/// the use of alternate datasources, e.g. as a result of server's
+/// reconfiguration. However, the use of the primary host data source (i.e.
+/// reservations specified in the configuration file) can't be disabled.
+class HostMgr : public boost::noncopyable, public BaseHostDataSource {
+public:
+
+ /// @brief Creates new instance of the @c HostMgr.
+ ///
+ /// If an instance of the @c HostMgr already exists, it will be replaced
+ /// by the new instance. Thus, any instances of alternate host data
+ /// sources will be dropped.
+ ///
+ static void create();
+
+ /// @brief Add an alternate host backend (aka host data source).
+ ///
+ /// @param access Host backend access parameters for the alternate
+ /// host backend. It holds "keyword=value" pairs, separated by spaces.
+ ///
+ /// The supported values are specific to the alternate backend in use.
+ /// However, the "type" parameter will be common and it will specify which
+ /// backend is to be used. Currently, no parameters are supported
+ /// and the parameter is ignored.
+ static void addBackend(const std::string& access);
+
+ /// @brief Delete an alternate host backend (aka host data source).
+ ///
+ /// @param db_type database backend type.
+ /// @return true when found and removed, false when not found.
+ static bool delBackend(const std::string& db_type);
+
+ /// @brief Delete an alternate host backend (aka host data source).
+ ///
+ /// @param db_type database backend type.
+ /// @param access Host backend access parameters for the alternate
+ /// host backend. It holds "keyword=value" pairs, separated by spaces.
+ /// @param if_unusable flag which indicates if the host data source should
+ /// be deleted only if it is unusable.
+ /// @return false when not removed because it is not found or because it is
+ /// still usable (if_unusable is true), true otherwise.
+ static bool delBackend(const std::string& db_type,
+ const std::string& access,
+ bool if_unusable = false);
+
+ /// @brief Delete all alternate backends.
+ static void delAllBackends();
+
+ /// @brief Check for the cache host backend.
+ ///
+ /// Checks if the first host backend implements
+ /// the cache abstract class and sets cache_ptr_.
+ ///
+ /// @param logging When true (not the default) emit an informational log.
+ /// @return true if the first host backend is a cache.
+ static bool checkCacheBackend(bool logging = false);
+
+ /// @brief Returns a sole instance of the @c HostMgr.
+ ///
+ /// This method should be used to retrieve an instance of the @c HostMgr
+ /// to be used to gather/manage host reservations. It returns an instance
+ /// of the @c HostMgr created by the @c create method. If such instance
+ /// doesn't exist yet, it is created using the @c create method with the
+ /// default value of the data access string, which configures the host
+ /// manager to not use the alternate host data source.
+ static HostMgr& instance();
+
+ /// @brief Return all hosts connected to any subnet for which reservations
+ /// have been made using a specified identifier.
+ ///
+ /// This method returns all @c Host objects representing reservations for
+ /// a specified identifier as documented in the
+ /// @c BaseHostDataSource::getAll.
+ ///
+ /// It retrieves reservations from both primary and alternate host data
+ /// source as a single collection of @c Host objects, i.e. if matching
+ /// reservations are in both sources, all of them are returned. The
+ /// reservations from the primary data source are placed before the
+ /// reservations from the alternate source.
+ ///
+ /// @param identifier_type Identifier type.
+ /// @param identifier_begin Pointer to a beginning of a buffer containing
+ /// an identifier.
+ /// @param identifier_len Identifier length.
+ ///
+ /// @return Collection of const @c Host objects.
+ virtual ConstHostCollection
+ getAll(const Host::IdentifierType& identifier_type,
+ const uint8_t* identifier_begin,
+ const size_t identifier_len) const;
+
+ /// @brief Return all hosts in a DHCPv4 subnet.
+ ///
+ /// This method returns all @c Host objects representing reservations
+ /// in a specified subnet as documented in the
+ /// @c BaseHostDataSource::getAll4
+ ///
+ /// It retrieves reservations from both primary and alternate host data
+ /// source as a single collection of @c Host objects, i.e. if matching
+ /// reservations are in both sources, all of them are returned. The
+ /// reservations from the primary data source are placed before the
+ /// reservations from the alternate source.
+ ///
+ /// @param subnet_id Subnet identifier.
+ ///
+ /// @return Collection of const @c Host objects.
+ virtual ConstHostCollection
+ getAll4(const SubnetID& subnet_id) const;
+
+ /// @brief Return all hosts in a DHCPv6 subnet.
+ ///
+ /// This method returns all @c Host objects representing reservations
+ /// in a specified subnet as documented in the
+ /// @c BaseHostDataSource::getAll6
+ ///
+ /// It retrieves reservations from both primary and alternate host data
+ /// source as a single collection of @c Host objects, i.e. if matching
+ /// reservations are in both sources, all of them are returned. The
+ /// reservations from the primary data source are placed before the
+ /// reservations from the alternate source.
+ ///
+ /// @param subnet_id Subnet identifier.
+ ///
+ /// @return Collection of const @c Host objects.
+ virtual ConstHostCollection
+ getAll6(const SubnetID& subnet_id) const;
+
+ /// @brief Return all hosts with a hostname.
+ ///
+ /// This method returns all @c Host objects which represent reservations
+ /// using a specified hostname.
+ ///
+ /// @param hostname The lower case hostname.
+ ///
+ /// @return Collection of const @c Host objects.
+ virtual ConstHostCollection
+ getAllbyHostname(const std::string& hostname) const;
+
+ /// @brief Return all hosts with a hostname in a DHCPv4 subnet.
+ ///
+ /// This method returns all @c Host objects which represent reservations
+ /// using a specified hostname in a specified subnet.
+ ///
+ /// @param hostname The lower case hostname.
+ /// @param subnet_id Subnet identifier.
+ ///
+ /// @return Collection of const @c Host objects.
+ virtual ConstHostCollection
+ getAllbyHostname4(const std::string& hostname, const SubnetID& subnet_id) const;
+
+ /// @brief Return all hosts with a hostname in a DHCPv6 subnet.
+ ///
+ /// This method returns all @c Host objects which represent reservations
+ /// using a specified hostname in a specified subnet.
+ ///
+ /// @param hostname The lower case hostname.
+ /// @param subnet_id Subnet identifier.
+ ///
+ /// @return Collection of const @c Host objects.
+ virtual ConstHostCollection
+ getAllbyHostname6(const std::string& hostname, const SubnetID& subnet_id) const;
+
+ /// @brief Returns range of hosts in a DHCPv4 subnet.
+ ///
+ /// This method returns a page of @c Host objects representing
+ /// reservations in a specified subnet as documented in the
+ /// @c BaseHostDataSource::getPage4
+ ///
+ /// The typical usage of this method is as follows:
+ /// - Get the first page of hosts by specifying zero index and id
+ /// as the beginning of the range.
+ /// - Index and last id of the returned range should be used as
+ /// starting index and id for the next page in the subsequent call.
+ /// - All returned hosts are from the same source so if the number of
+ /// hosts returned is lower than the page size, it does not indicate
+ /// that the last page has been retrieved.
+ /// - If there are no hosts returned it indicates that the previous page
+ /// was the last page.
+ ///
+ /// @param subnet_id Subnet identifier.
+ /// @param source_index Index of the source.
+ /// @param lower_host_id Host identifier used as lower bound for the
+ /// returned range.
+ /// @param page_size maximum size of the page returned.
+ ///
+ /// @return Host collection (may be empty).
+ virtual ConstHostCollection
+ getPage4(const SubnetID& subnet_id,
+ size_t& source_index,
+ uint64_t lower_host_id,
+ const HostPageSize& page_size) const;
+
+ /// @brief Returns range of hosts in a DHCPv6 subnet.
+ ///
+ /// This method returns a page of @c Host objects representing
+ /// reservations in a specified subnet as documented in the
+ /// @c BaseHostDataSource::getPage6
+ ///
+ /// The typical usage of this method is as follows:
+ /// - Get the first page of hosts by specifying zero index and id
+ /// as the beginning of the range.
+ /// - Index and last id of the returned range should be used as
+ /// starting index and id for the next page in the subsequent call.
+ /// - All returned hosts are from the same source so if the number of
+ /// hosts returned is lower than the page size, it does not indicate
+ /// that the last page has been retrieved.
+ /// - If there are no hosts returned it indicates that the previous page
+ /// was the last page.
+ ///
+ /// @param subnet_id Subnet identifier.
+ /// @param source_index Index of the source.
+ /// @param lower_host_id Host identifier used as lower bound for the
+ /// returned range.
+ /// @param page_size maximum size of the page returned.
+ ///
+ /// @return Host collection (may be empty).
+ virtual ConstHostCollection
+ getPage6(const SubnetID& subnet_id,
+ size_t& source_index,
+ uint64_t lower_host_id,
+ const HostPageSize& page_size) const;
+
+ /// @brief Returns range of hosts.
+ ///
+ /// This method returns a page of @c Host objects representing
+ /// reservations as documented in the @c BaseHostDataSource::getPage4
+ ///
+ /// The typical usage of this method is as follows:
+ /// - Get the first page of hosts by specifying zero index and id
+ /// as the beginning of the range.
+ /// - Index and last id of the returned range should be used as
+ /// starting index and id for the next page in the subsequent call.
+ /// - All returned hosts are from the same source so if the number of
+ /// hosts returned is lower than the page size, it does not indicate
+ /// that the last page has been retrieved.
+ /// - If there are no hosts returned it indicates that the previous page
+ /// was the last page.
+ ///
+ /// @param source_index Index of the source.
+ /// @param lower_host_id Host identifier used as lower bound for the
+ /// returned range.
+ /// @param page_size maximum size of the page returned.
+ ///
+ /// @return Host collection (may be empty).
+ virtual ConstHostCollection
+ getPage4(size_t& source_index,
+ uint64_t lower_host_id,
+ const HostPageSize& page_size) const;
+
+ /// @brief Returns range of hosts.
+ ///
+ /// This method returns a page of @c Host objects representing
+ /// reservations as documented in the @c BaseHostDataSource::getPage6
+ ///
+ /// The typical usage of this method is as follows:
+ /// - Get the first page of hosts by specifying zero index and id
+ /// as the beginning of the range.
+ /// - Index and last id of the returned range should be used as
+ /// starting index and id for the next page in the subsequent call.
+ /// - All returned hosts are from the same source so if the number of
+ /// hosts returned is lower than the page size, it does not indicate
+ /// that the last page has been retrieved.
+ /// - If there are no hosts returned it indicates that the previous page
+ /// was the last page.
+ ///
+ /// @param source_index Index of the source.
+ /// @param lower_host_id Host identifier used as lower bound for the
+ /// returned range.
+ /// @param page_size maximum size of the page returned.
+ ///
+ /// @return Host collection (may be empty).
+ virtual ConstHostCollection
+ getPage6(size_t& source_index,
+ uint64_t lower_host_id,
+ const HostPageSize& page_size) const;
+
+ /// @brief Returns a collection of hosts using the specified IPv4 address.
+ ///
+ /// This method may return multiple @c Host objects if they are connected to
+ /// different subnets.
+ ///
+ /// If matching reservations are both in the primary and the alternate
+ /// data source, all of them are returned. The reservations from the
+ /// primary data source are placed before the reservations from the
+ /// alternate source.
+ ///
+ /// @param address IPv4 address for which the @c Host object is searched.
+ ///
+ /// @return Collection of const @c Host objects.
+ virtual ConstHostCollection
+ getAll4(const asiolink::IOAddress& address) const;
+
+ /// @brief Returns any host connected to the IPv4 subnet.
+ ///
+ /// This method returns a single reservation for a particular host as
+ /// documented in the @c BaseHostDataSource::get4 even when the
+ /// reservation is marked as from negative caching. This allows to
+ /// monitor negative caching.
+ ///
+ /// @param subnet_id Subnet identifier.
+ /// @param identifier_type Identifier type.
+ /// @param identifier_begin Pointer to a beginning of a buffer containing
+ /// an identifier.
+ /// @param identifier_len Identifier length.
+ ///
+ /// @return Const @c Host object for which reservation has been made using
+ /// the specified identifier.
+ virtual ConstHostPtr
+ get4Any(const SubnetID& subnet_id,
+ const Host::IdentifierType& identifier_type,
+ const uint8_t* identifier_begin,
+ const size_t identifier_len) const;
+
+ /// @brief Returns a host connected to the IPv4 subnet.
+ ///
+ /// This method returns a single reservation for a particular host as
+ /// documented in the @c BaseHostDataSource::get4.
+ ///
+ /// @param subnet_id Subnet identifier.
+ /// @param identifier_type Identifier type.
+ /// @param identifier_begin Pointer to a beginning of a buffer containing
+ /// an identifier.
+ /// @param identifier_len Identifier length.
+ ///
+ /// @return Const @c Host object for which reservation has been made using
+ /// the specified identifier.
+ virtual ConstHostPtr
+ get4(const SubnetID& subnet_id, const Host::IdentifierType& identifier_type,
+ const uint8_t* identifier_begin, const size_t identifier_len) const;
+
+ /// @brief Returns a host connected to the IPv4 subnet and having
+ /// a reservation for a specified IPv4 address.
+ ///
+ /// This method returns a single reservation for the particular host
+ /// (identified by the HW address or DUID) as documented in the
+ /// @c BaseHostDataSource::get4.
+ ///
+ /// @param subnet_id Subnet identifier.
+ /// @param address reserved IPv4 address.
+ ///
+ /// @return Const @c Host object using a specified IPv4 address.
+ virtual ConstHostPtr
+ get4(const SubnetID& subnet_id, const asiolink::IOAddress& address) const;
+
+ /// @brief Returns all hosts connected to the IPv4 subnet and having
+ /// a reservation for a specified address.
+ ///
+ /// In most cases it is desired that there is at most one reservation
+ /// for a given IPv4 address within a subnet. In a default configuration,
+ /// the backend does not allow for inserting more than one host with
+ /// the same IPv4 reservation. In that case, the number of hosts returned
+ /// by this function is 0 or 1.
+ ///
+ /// If the backend is configured to allow multiple hosts with reservations
+ /// for the same IPv4 address in the given subnet, this method can return
+ /// more than one host.
+ ///
+ /// The typical use case when a single IPv4 address is reserved for multiple
+ /// hosts is when these hosts represent different interfaces of the same
+ /// machine and each interface comes with a different MAC address. In that
+ /// case, the same IPv4 address is assigned regardless of which interface is
+ /// used by the DHCP client to communicate with the server.
+ ///
+ /// @param subnet_id Subnet identifier.
+ /// @param address reserved IPv4 address.
+ ///
+ /// @return Collection of const @c Host objects.
+ virtual ConstHostCollection
+ getAll4(const SubnetID& subnet_id,
+ const asiolink::IOAddress& address) const;
+
+ /// @brief Returns any host connected to the IPv6 subnet.
+ ///
+ /// This method returns a host connected to the IPv6 subnet as described
+ /// in the @c BaseHostDataSource::get6 even when the
+ /// reservation is marked as from negative caching. This allows to
+ /// monitor negative caching.
+ ///
+ /// @param subnet_id Subnet identifier.
+ /// @param identifier_type Identifier type.
+ /// @param identifier_begin Pointer to a beginning of a buffer containing
+ /// an identifier.
+ /// @param identifier_len Identifier length.
+ ///
+ /// @return Const @c Host object for which reservation has been made using
+ /// the specified identifier.
+ virtual ConstHostPtr
+ get6Any(const SubnetID& subnet_id,
+ const Host::IdentifierType& identifier_type,
+ const uint8_t* identifier_begin,
+ const size_t identifier_len) const;
+
+ /// @brief Returns a host connected to the IPv6 subnet.
+ ///
+ /// This method returns a host connected to the IPv6 subnet as described
+ /// in the @c BaseHostDataSource::get6.
+ ///
+ /// @param subnet_id Subnet identifier.
+ /// @param identifier_type Identifier type.
+ /// @param identifier_begin Pointer to a beginning of a buffer containing
+ /// an identifier.
+ /// @param identifier_len Identifier length.
+ ///
+ /// @return Const @c Host object for which reservation has been made using
+ /// the specified identifier.
+ virtual ConstHostPtr
+ get6(const SubnetID& subnet_id, const Host::IdentifierType& identifier_type,
+ const uint8_t* identifier_begin, const size_t identifier_len) const;
+
+ /// @brief Returns a host using the specified IPv6 prefix.
+ ///
+ /// This method returns a host using specified IPv6 prefix, as described
+ /// in the @c BaseHostDataSource::get6.
+ ///
+ /// @param prefix IPv6 prefix for which the @c Host object is searched.
+ /// @param prefix_len IPv6 prefix length.
+ ///
+ /// @return Const @c Host object using a specified IPv6 prefix.
+ virtual ConstHostPtr
+ get6(const asiolink::IOAddress& prefix, const uint8_t prefix_len) const;
+
+ /// @brief Returns a host from specific subnet and reserved address.
+ ///
+ /// @param subnet_id subnet identifier.
+ /// @param addr specified address.
+ ///
+ /// @return Const @c host object that has a reservation for specified address.
+ virtual ConstHostPtr
+ get6(const SubnetID& subnet_id, const asiolink::IOAddress& addr) const;
+
+ /// @brief Returns all hosts connected to the IPv6 subnet and having
+ /// a reservation for a specified address or delegated prefix (lease).
+ ///
+ /// In most cases it is desired that there is at most one reservation
+ /// for a given IPv6 lease within a subnet. In a default configuration,
+ /// the backend does not allow for inserting more than one host with
+ /// the same IPv6 address or prefix. In that case, the number of hosts
+ /// returned by this function is 0 or 1.
+ ///
+ /// If the backend is configured to allow multiple hosts with reservations
+ /// for the same IPv6 lease in the given subnet, this method can return
+ /// more than one host.
+ ///
+ /// The typical use case when a single IPv6 lease is reserved for multiple
+ /// hosts is when these hosts represent different interfaces of the same
+ /// machine and each interface comes with a different MAC address. In that
+ /// case, the same IPv6 lease is assigned regardless of which interface is
+ /// used by the DHCP client to communicate with the server.
+ ///
+ /// @param subnet_id Subnet identifier.
+ /// @param address reserved IPv6 address/prefix.
+ ///
+ /// @return Collection of const @c Host objects.
+ virtual ConstHostCollection
+ getAll6(const SubnetID& subnet_id,
+ const asiolink::IOAddress& address) const;
+
+ /// @brief Adds a new host to the alternate data source.
+ ///
+ /// This method will throw an exception if no alternate data source is
+ /// in use.
+ ///
+ /// @param host Pointer to the new @c Host object being added.
+ virtual void add(const HostPtr& host);
+
+ /// @brief Attempts to delete hosts by address.
+ ///
+ /// It deletes hosts from the first alternate source in which at least
+ /// one matching host is found. In unlikely case that the hosts having
+ /// the same IP address exist in other alternate sources, the hosts
+ /// from these other sources are not deleted.
+ ///
+ /// This method supports both v4 and v6.
+ ///
+ /// @param subnet_id subnet identifier.
+ /// @param addr specified address.
+ /// @return true if deletion was successful, false otherwise.
+ virtual bool del(const SubnetID& subnet_id, const asiolink::IOAddress& addr);
+
+ /// @brief Attempts to delete a host by (subnet4-id, identifier, identifier-type)
+ ///
+ /// This method supports v4 only.
+ ///
+ /// @param subnet_id IPv4 Subnet identifier.
+ /// @param identifier_type Identifier type.
+ /// @param identifier_begin Pointer to a beginning of a buffer containing
+ /// an identifier.
+ /// @param identifier_len Identifier length.
+ /// @return true if deletion was successful, false otherwise.
+ virtual bool
+ del4(const SubnetID& subnet_id, const Host::IdentifierType& identifier_type,
+ const uint8_t* identifier_begin, const size_t identifier_len);
+
+ /// @brief Attempts to delete a host by (subnet6-id, identifier, identifier-type)
+ ///
+ /// This method supports v6 only.
+ ///
+ /// @param subnet_id IPv6 Subnet identifier.
+ /// @param identifier_type Identifier type.
+ /// @param identifier_begin Pointer to a beginning of a buffer containing
+ /// an identifier.
+ /// @param identifier_len Identifier length.
+ /// @return true if deletion was successful, false otherwise.
+ virtual bool
+ del6(const SubnetID& subnet_id, const Host::IdentifierType& identifier_type,
+ const uint8_t* identifier_begin, const size_t identifier_len);
+
+ /// @brief Return backend type
+ ///
+ /// Returns the type of the backend (e.g. "mysql", "memfile" etc.)
+ ///
+ /// @return Type of the backend.
+ virtual std::string getType() const {
+ return (std::string("host_mgr"));
+ }
+
+ /// @brief Returns the host data source list.
+ ///
+ /// @return reference to the host data source list.
+ HostDataSourceList& getHostDataSourceList() {
+ return (alternate_sources_);
+ }
+
+ /// @brief Returns the first host data source.
+ ///
+ /// May return NULL if the host data source list is empty.
+ /// @return pointer to the first host data source (or NULL).
+ HostDataSourcePtr getHostDataSource() const;
+
+ /// @brief Returns the negative caching flag.
+ ///
+ /// @return the negative caching flag.
+ bool getNegativeCaching() const {
+ return (negative_caching_);
+ }
+
+ /// @brief Sets the negative caching flag.
+ ///
+ void setNegativeCaching(bool negative_caching) {
+ negative_caching_ = negative_caching;
+ }
+
+ /// @brief Returns the disable single query flag.
+ ///
+ /// @return the disable single query flag.
+ bool getDisableSingleQuery() const {
+ return (disable_single_query_);
+ }
+
+ /// @brief Sets the disable single query flag.
+ ///
+ void setDisableSingleQuery(bool disable_single_query) {
+ disable_single_query_ = disable_single_query;
+ }
+
+ /// @brief Controls whether IP reservations are unique or non-unique.
+ ///
+ /// In a typical case, the IP reservations are unique and backends verify
+ /// prior to adding a host reservation to the database that the reservation
+ /// for a given IP address/subnet does not exist. In some cases it may be
+ /// required to allow non-unique IP reservations, e.g. in the case when a
+ /// host has several interfaces and independently of which interface is used
+ /// by this host to communicate with the DHCP server the same IP address
+ /// should be assigned. In this case the @c unique value should be set to
+ /// false to disable the checks for uniqueness on the backend side.
+ ///
+ /// Calling this function on @c HostMgr causes the manager to attempt to
+ /// set this flag on all backends in use.
+ ///
+ /// @param unique boolean flag indicating if the IP reservations must be
+ /// unique or can be non-unique.
+ /// @return true if the new setting was accepted by the backend or false
+ /// otherwise.
+ virtual bool setIPReservationsUnique(const bool unique);
+
+ /// @brief Returns the boolean flag indicating if the IP reservations
+ /// must be unique or can be non-unique.
+ ///
+ /// @return true if IP reservations must be unique or false if IP
+ /// reservations can be non-unique.
+ bool getIPReservationsUnique() const {
+ return (ip_reservations_unique_);
+ }
+
+ /// @brief Sets IO service to be used by the Host Manager.
+ ///
+ /// @param io_service IOService object, used for all ASIO operations.
+ static void setIOService(const isc::asiolink::IOServicePtr& io_service) {
+ io_service_ = io_service;
+ }
+
+ /// @brief Returns pointer to the IO service.
+ static isc::asiolink::IOServicePtr& getIOService() {
+ return (io_service_);
+ }
+
+protected:
+
+ /// @brief The negative caching flag.
+ ///
+ /// When true and the first backend is a cache
+ /// negative answers are inserted in the cache.
+ /// This works for get[46] for a subnet and an identifier.
+ bool negative_caching_;
+
+ /// @brief The disable single query flag.
+ ///
+ /// When true prevent the use of lookup methods returning a collection
+ /// aka single queries when methods returning a host object are usable
+ /// instead.
+ bool disable_single_query_;
+
+ /// @brief Cache an answer.
+ ///
+ /// @param host Pointer to the missed host.
+ virtual void cache(ConstHostPtr host) const;
+
+ /// @brief Cache a negative answer.
+ ///
+ /// @param ipv4_subnet_id Identifier of the IPv4 subnet.
+ /// @param ipv6_subnet_id Identifier of the IPv6 subnet.
+ /// @param identifier_type Identifier type.
+ /// @param identifier_begin Pointer to a beginning of the Identifier.
+ /// @param identifier_len Identifier length.
+ virtual void cacheNegative(const SubnetID& ipv4_subnet_id,
+ const SubnetID& ipv6_subnet_id,
+ const Host::IdentifierType& identifier_type,
+ const uint8_t* identifier_begin,
+ const size_t identifier_len) const;
+
+private:
+
+ /// @brief Indicates if backends are running in the mode in which IP
+ /// reservations must be unique (true) or non-unique (false).
+ ///
+ /// This flag is set to false only after calling @c setIPReservationsUnique
+ /// with the @c unique value set to false and after this setting was
+ /// successfully applied to all backends.
+ bool ip_reservations_unique_;
+
+ /// @brief Private default constructor.
+ HostMgr() : negative_caching_(false), disable_single_query_(false),
+ ip_reservations_unique_(true) { }
+
+ /// @brief List of alternate host data sources.
+ HostDataSourceList alternate_sources_;
+
+ /// @brief Pointer to the cache.
+ CacheHostDataSourcePtr cache_ptr_;
+
+ /// @brief Returns a pointer to the currently used instance of the
+ /// @c HostMgr.
+ static boost::scoped_ptr<HostMgr>& getHostMgrPtr();
+
+ /// The IOService object, used for all ASIO operations.
+ static isc::asiolink::IOServicePtr io_service_;
+};
+
+} // namespace dhcp
+} // namespace isc
+
+#endif // HOST_MGR_H