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// Copyright (C) 2018-2024 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 HA_IMPL_H
#define HA_IMPL_H
#include <ha_config.h>
#include <ha_service.h>
#include <asiolink/io_service.h>
#include <cc/data.h>
#include <dhcpsrv/network_state.h>
#include <hooks/hooks.h>
#include <boost/noncopyable.hpp>
#include <boost/shared_ptr.hpp>
namespace isc {
namespace ha {
/// @brief High Availability hooks library implementation.
///
/// This object provides an interface between the HA hook library callouts
/// and the HA state model implemented in the @c HAService. Callouts invoke
/// respective methods of the @c HAImpl to configure the service, generate
/// lease updates etc. The @c HAImpl retrieves and validates the arguments
/// provided within @c CalloutHandle object and then invokes appropriate
/// methods of the @c HAService class.
class HAImpl : public boost::noncopyable {
public:
/// @brief Constructor.
HAImpl();
/// @brief Parses configuration.
///
/// @param input_config Configuration specified for the hooks library.
/// @throw ConfigError when configuration fails.
void configure(const data::ConstElementPtr& input_config);
/// @brief Creates high availability services using current configuration.
///
/// The caller must ensure that the HA configuration is valid before
/// calling this function.
///
/// @param io_service IO service object provided by the DHCP server.
/// @param network_state pointer to the object holding a state of the
/// DHCP service (enabled/disabled).
/// @param server_type DHCP server type for which the HA service should
/// be created.
void startServices(const asiolink::IOServicePtr& io_service,
const dhcp::NetworkStatePtr& network_state,
const HAServerType& server_type);
/// @brief Destructor.
~HAImpl();
/// @brief Returns a configuration for the first relationship.
///
/// This function is held here for historical reasons and it is currently
/// only used in the unit tests for a single-relationship test cases. The
/// production code should use the other variant of this function that
/// includes a partner name as a parameter. It coveres both the cases when
/// there is only one relationship and the hub-and-spoke case.
///
/// @return Configuration for the relationship to which the partner belongs.
/// @throw InvalidOperation when there are no relationships.
HAConfigPtr getConfig() const {
return (config_->get());
}
/// @brief Returns parsed configuration by partner name.
///
/// @param partner_name name of a partner belonging to the relationship for
/// which the configuration should be retrieved.
/// @return Configuration for the relationship to which the partner belongs.
HAConfigPtr getConfig(const std::string& partner_name) const {
return (config_->get(partner_name));
}
/// @brief Implementation of the "buffer4_receive" callout.
///
/// This callout uses HA service to check if the query should be processed
/// by this server or a partner. If the partner should process the query,
/// this callout sets the status to @c CalloutHandle::NEXT_STEP_DROP to
/// cause the server to drop the packet. Therefore it is important to note
/// that, if multiple hook libraries implementing @c buffer4_receive hook are
/// loaded, the order of loading the libraries may matter. If this library
/// sets the status to @c CalloutHandle::NEXT_STEP_DROP and the other library
/// overrides this status, the query will be processed by the server instead
/// of being dropped. This problem may be mitigated by loading the HA library
/// last, i.e. placing the library at the end of the "hooks-libraries"
/// list within a Kea configuration file.
///
/// If the received query is to be processed by this server instance, the
/// @c CalloutHabndle::NEXT_STEP_SKIP status is set to prevent the server
/// from unpacking the query because the query is unpacked by the callout.
///
/// @param callout_handle Callout handle provided to the callout.
void buffer4Receive(hooks::CalloutHandle& callout_handle);
/// @brief Implementation of the "subnet4_select" callout.
///
/// This callout decides whether the received packet should be processed
/// by the server when the server has multiple HA relationships. The
/// relationship selection is based on the selected subnet.
///
/// @param callout_handle Callout handle provided to the callout.
void subnet4Select(hooks::CalloutHandle& callout_handle);
/// @brief Implementation of the "leases4_committed" callout.
///
/// @param callout_handle Callout handle provided to the callout.
void leases4Committed(hooks::CalloutHandle& callout_handle);
/// @brief Implementation of the "lease4_server_decline" callout.
///
/// @param callout_handle Callout handle provided to the callout.
void lease4ServerDecline(hooks::CalloutHandle& callout_handle);
/// @brief Implementation of the "buffer6_receive" callout.
///
/// This callout uses HA service to check if the query should be processed
/// by this server or a partner. If the partner should process the query,
/// this callout sets the status to @c CalloutHandle::NEXT_STEP_DROP to
/// cause the server to drop the packet. Therefore it is important to note
/// that, if multiple hook libraries implementing @c buffer6_receive hook are
/// loaded, the order of loading the libraries may matter. If this library
/// sets the status to @c CalloutHandle::NEXT_STEP_DROP and the other library
/// overrides this status, the query will be processed by the server instead
/// of being dropped. This problem may be mitigated by loading the HA library
/// last, i.e. placing the library at the end of the "hooks-libraries"
/// list within a Kea configuration file.
///
/// If the received query is to be processed by this server instance, the
/// @c CalloutHabndle::NEXT_STEP_SKIP status is set to prevent the server
/// from unpacking the query because the query is unpacked by the callout.
///
/// @param callout_handle Callout handle provided to the callout.
void buffer6Receive(hooks::CalloutHandle& callout_handle);
/// @brief Implementation of the "subnet6_select" callout.
///
/// This callout decides whether the received packet should be processed
/// by the server when the server has multiple HA relationships. The
/// relationship selection is based on the selected subnet.
///
/// @param callout_handle Callout handle provided to the callout.
void subnet6Select(hooks::CalloutHandle& callout_handle);
/// @brief Implementation of the "leases6_committed" callout.
///
/// @param callout_handle Callout handle provided to the callout.
void leases6Committed(hooks::CalloutHandle& callout_handle);
/// @brief Implementation of the "command_processed" callout.
///
/// It adds the HA servers information to "status-get" command responses by
/// calling @c HAService::commandProcessed.
///
/// @param callout_handle Callout handle provided to the callout.
void commandProcessed(hooks::CalloutHandle& callout_handle);
/// @brief Implements handle for the heartbeat command.
///
/// @param callout_handle Callout handle provided to the callout.
void heartbeatHandler(hooks::CalloutHandle& callout_handle);
/// @brief Implements handler for the ha-sync command.
///
/// @param callout_handle Callout handle provided to the callout.
void synchronizeHandler(hooks::CalloutHandle& callout_handle);
/// @brief Implements handler for the ha-scopes command.
///
/// @param callout_handle Callout handle provided to the callout.
void scopesHandler(hooks::CalloutHandle& callout_handle);
/// @brief Implements handler for the ha-continue command.
///
/// @param callout_handle Callout handle provided to the callout.
void continueHandler(hooks::CalloutHandle& callout_handle);
/// @brief Implements handler for the ha-maintenance-notify command.
///
/// @param callout_handle Callout handle provided to the callout.
void maintenanceNotifyHandler(hooks::CalloutHandle& callout_handle);
/// @brief Implements handler for the ha-maintenance-start command.
///
/// @param callout_handle Callout handle provided to the callout.
void maintenanceStartHandler(hooks::CalloutHandle& callout_handle);
/// @brief Implements handler for the ha-maintenance-cancel command.
///
/// @param callout_handle Callout handle provided to the callout.
void maintenanceCancelHandler(hooks::CalloutHandle& callout_handle);
/// @brief Implements handler for the ha-reset command.
///
/// @param callout_handle Callout handle provided to the callout.
void haResetHandler(hooks::CalloutHandle& callout_handle);
/// @brief Implements handler for the ha-sync-complete-notify command.
///
/// @param callout_handle Callout handle provided to the callout.
void syncCompleteNotifyHandler(hooks::CalloutHandle& callout_handle);
/// @brief Attempts to get an @c HAService by server name.
///
/// The function expects that the arguments contain the "server-name"
/// parameter. If the parameter is not specified, a default @c HAService
/// name is returned.
///
/// @param command_name command name (used for logging purposes only).
/// @param args command arguments or null.
/// @return Pointer to an @c HAService instance.
/// @throw BadValue if the specified server-name doesn't exist or if the
/// server-name wasn't specified and more than one @c HAService exists.
HAServicePtr getHAServiceByServerName(const std::string& command_name,
data::ConstElementPtr args) const;
protected:
/// @brief Holds parsed configuration.
HAConfigMapperPtr config_;
/// @brief Pointer to the high availability services (state machines).
HAServiceMapperPtr services_;
};
/// @brief Pointer to the High Availability hooks library implementation.
typedef boost::shared_ptr<HAImpl> HAImplPtr;
} // end of namespace isc::ha
} // end of namespace isc
#endif
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