Adding upstream version 2.4.1.upstream/2.4.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 357 insertions, 0 deletions

diff --git a/src/lib/dhcpsrv/cfgmgr.h b/src/lib/dhcpsrv/cfgmgr.h
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+++ b/src/lib/dhcpsrv/cfgmgr.h
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+// Copyright (C) 2012-2022 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 CFGMGR_H
+#define CFGMGR_H
+
+#include <asiolink/io_address.h>
+#include <dhcp/option.h>
+#include <dhcp/option_space.h>
+#include <dhcp/classify.h>
+#include <dhcpsrv/d2_client_mgr.h>
+#include <dhcpsrv/pool.h>
+#include <dhcpsrv/srv_config.h>
+#include <util/buffer.h>
+#include <util/optional.h>
+
+#include <boost/shared_ptr.hpp>
+#include <boost/noncopyable.hpp>
+
+#include <map>
+#include <string>
+#include <vector>
+#include <list>
+
+namespace isc {
+namespace dhcp {
+
+/// @brief Exception thrown when the same interface has been specified twice.
+///
+/// In particular, this exception is thrown when adding interface to the set
+/// of interfaces on which server is supposed to listen.
+class DuplicateListeningIface : public Exception {
+public:
+    DuplicateListeningIface(const char* file, size_t line, const char* what) :
+        isc::Exception(file, line, what) { };
+};
+
+/// @brief Configuration Manager
+///
+/// This singleton class holds the whole configuration for DHCPv4 and DHCPv6
+/// servers.
+///
+/// Below is a sketch of configuration inheritance.
+/// Let's investigate the following configuration:
+///
+/// @code
+/// preferred-lifetime 500;
+/// valid-lifetime 1000;
+/// subnet6 2001:db8:1::/48 {
+///     pool6 2001::db8:1::1 - 2001::db8:1::ff;
+/// };
+/// subnet6 2001:db8:2::/48 {
+///     valid-lifetime 2000;
+///     pool6 2001::db8:2::1 - 2001::db8:2::ff;
+/// };
+/// @endcode
+///
+/// Parameters defined in a global scope are applicable to everything until
+/// they are overwritten in a smaller scope, in this case subnet6.
+/// In the example above, the first subnet6 has preferred lifetime of 500s
+/// and a valid lifetime of 1000s. The second subnet has preferred lifetime
+/// of 500s, but valid lifetime of 2000s.
+///
+/// Parameter inheritance is implemented in dedicated classes. See
+/// @ref isc::dhcp::SimpleParser4::deriveParameters and
+/// @ref isc::dhcp::SimpleParser6::deriveParameters.
+class CfgMgr : public boost::noncopyable {
+public:
+
+    /// @brief A number of configurations held by @c CfgMgr.
+    ///
+    /// @todo Make it configurable.
+    static const size_t CONFIG_LIST_SIZE;
+
+    /// @brief returns a single instance of Configuration Manager
+    ///
+    /// CfgMgr is a singleton and this method is the only way of
+    /// accessing it.
+    static CfgMgr& instance();
+
+    /// @brief returns path do the data directory
+    ///
+    /// This method returns a path to writable directory that DHCP servers
+    /// can store data in.
+    /// @return data directory
+    util::Optional<std::string> getDataDir() const;
+
+    /// @brief Sets new data directory.
+    ///
+    /// @param datadir New data directory.
+    /// @param unspecified Initial state. Default is "unspecified".
+    void setDataDir(const std::string& datadir, bool unspecified = true);
+
+    /// @brief Updates the DHCP-DDNS client configuration to the given value.
+    ///
+    /// Passes the new configuration to the D2ClientMgr instance,
+    /// d2_client_mgr_, which will attempt to apply the new configuration
+    /// by shutting down its sender and opening a new connection per the new
+    /// configuration (see @c D2ClientMgr::setD2ClientConfig()).
+    ///
+    /// @param new_config pointer to the new client configuration.
+    ///
+    /// @throw Underlying method(s) will throw D2ClientError if given an empty
+    /// pointer.
+    void setD2ClientConfig(D2ClientConfigPtr& new_config);
+
+    /// @brief Convenience method for checking if DHCP-DDNS updates are enabled.
+    ///
+    /// @return True if the D2 configuration is enabled.
+    bool ddnsEnabled();
+
+    /// @brief Fetches the DHCP-DDNS configuration pointer.
+    ///
+    /// @return a reference to the current configuration pointer.
+    const D2ClientConfigPtr& getD2ClientConfig() const;
+
+    /// @brief Fetches the DHCP-DDNS manager.
+    ///
+    /// @return a reference to the DHCP-DDNS manager.
+    D2ClientMgr& getD2ClientMgr();
+
+    /// @name Methods managing the collection of configurations.
+    ///
+    /// The following methods manage the process of preparing a configuration
+    /// without affecting a currently used configuration and then committing
+    /// the configuration to replace current configuration atomically.
+    /// They also allow for keeping a history of previous configurations so
+    /// as the @c CfgMgr can revert to the historical configuration when
+    /// required.
+    ///
+    /// @todo Migrate all configuration parameters to use the model supported
+    /// by these functions.
+    ///
+    /// @todo Make the size of the configurations history configurable.
+    ///
+    //@{
+
+    /// @brief Removes current, staging and all previous configurations.
+    ///
+    /// This function removes all configurations, including current,
+    /// staging and external configurations. It creates a new current
+    /// configuration with default settings.
+    ///
+    /// This function is exception safe.
+    void clear();
+
+    /// @brief Commits the staging configuration.
+    ///
+    /// The staging configuration becomes current configuration when this
+    /// function is called. It removes the oldest configuration held in the
+    /// history so as the size of the list of configuration does not exceed
+    /// the @c CONFIG_LIST_SIZE.
+    ///
+    /// This function is exception safe.
+    void commit();
+
+    /// @brief Removes staging configuration.
+    ///
+    /// This function should be called when there is a staging configuration
+    /// (likely created in the previous configuration attempt) but the entire
+    /// new configuration should be created. It removes the existing staging
+    /// configuration and the next call to @c CfgMgr::getStagingCfg will return a
+    /// fresh (default) configuration.
+    ///
+    /// This function is exception safe.
+    void rollback();
+
+    /// @brief Reverts to one of the previous configurations.
+    ///
+    /// This function reverts to selected previous configuration. The previous
+    /// configuration is entirely copied to a new @c SrvConfig instance. This
+    /// new instance has a unique sequence id (sequence id is not copied). The
+    /// previous configuration (being copied) is not modified by this operation.
+    ///
+    /// The configuration to be copied is identified by the index value which
+    /// is the distance between the current (most recent) and desired
+    /// configuration. If the index is out of range an exception is thrown.
+    ///
+    /// @warning Revert operation will rollback any changes to the staging
+    /// configuration (if it exists).
+    ///
+    /// @warning This function requires that the entire previous configuration
+    /// is copied to the new configuration object. This is not working for
+    /// some of the complex configuration objects, e.g. subnets. Hence, the
+    /// "revert" operation is not really usable at this point.
+    ///
+    /// @param index A distance from the current configuration to the
+    /// past configuration to be reverted. The minimal value is 1 which points
+    /// to the nearest configuration.
+    ///
+    /// @throw isc::OutOfRange if the specified index is out of range.
+    void revert(const size_t index);
+
+    /// @brief Returns a pointer to the current configuration.
+    ///
+    /// This function returns pointer to the current configuration. If the
+    /// current configuration is not set it will create a default configuration
+    /// and return it.
+    ///
+    /// In the previous Kea releases this method used to return a const pointer
+    /// to the current configuration to ensure that it is not accidentally
+    /// modified while the server is running. This has been changed in Kea 1.3
+    /// release and now this function returns a non-const pointer. The reason
+    /// is that there are certain use cases when current configuration must
+    /// be modified without going through a full cycle of server
+    /// reconfiguration, e.g. add a subnet to the current configuration as
+    /// a result of receiving a command over control API. In such case the
+    /// performance of processing such command is critical and rebuilding the
+    /// whole configuration just for this small configuration change is out
+    /// of question.
+    ///
+    /// Nevertheless, such configuration updates should always be made with
+    /// caution and one has to make sure that the configuration data integrity
+    /// is preserved.
+    ///
+    /// @return Non-null pointer to the current configuration.
+    SrvConfigPtr getCurrentCfg();
+
+    /// @brief Returns a pointer to the staging configuration.
+    ///
+    /// The staging configuration is used by the configuration parsers to
+    /// create new configuration. The staging configuration doesn't affect the
+    /// server's operation until it is committed. The staging configuration
+    /// is a non-const object which can be modified by the caller.
+    ///
+    /// Multiple consecutive calls to this function return the same object
+    /// which can be modified from various places of the code (e.g. various
+    /// configuration parsers).
+    ///
+    /// @return non-null pointer to the staging configuration.
+    SrvConfigPtr getStagingCfg();
+
+    /// @brief Creates an external configuration and returns pointer to it.
+    ///
+    /// External configurations are those that come from other sources than
+    /// from the configuration file, e.g. a database or a command. They
+    /// are created aside and merged into the staging or current configuration.
+    /// External configurations are accessed by their sequence numbers. The
+    /// sequence numbers are autogenerated when the external configuration
+    /// instance is created.
+    ///
+    /// @return non-null pointer to created external configuration.
+    SrvConfigPtr createExternalCfg();
+
+    /// @brief Merges external configuration with the given sequence number
+    /// into the staging configuration.
+    ///
+    /// After the merge, the source configuration is discarded from the
+    /// @c CfgMgr as it should not be used anymore.
+    ///
+    /// @param seq Source configuration sequence number.
+    ///
+    /// @throw BadValue if the external configuration with the given sequence
+    /// number doesn't exist.
+    void mergeIntoStagingCfg(const uint32_t seq);
+
+    /// @brief Merges external configuration with the given sequence number
+    /// into the current configuration.
+    ///
+    /// After the merge, the source configuration is discarded from the
+    /// @c CfgMgr as it should not be used anymore.
+    ///
+    /// @param seq Source configuration sequence number.
+    ///
+    /// @throw BadValue if the external configuration with the given sequence
+    /// number doesn't exist.
+    void mergeIntoCurrentCfg(const uint32_t seq);
+
+    //@}
+
+    /// @brief Sets address family (AF_INET or AF_INET6)
+    void setFamily(uint16_t family) {
+        family_ = family == AF_INET ? AF_INET : AF_INET6;
+    }
+
+    /// @brief Returns address family.
+    uint16_t getFamily() const {
+        return (family_);
+    }
+
+    //@}
+
+protected:
+
+    /// @brief Protected constructor.
+    ///
+    /// This constructor is protected for 2 reasons. First, it forbids any
+    /// instantiations of this class (CfgMgr is a singleton). Second, it
+    /// allows derived class to instantiate it. That is useful for testing
+    /// purposes.
+    CfgMgr();
+
+    /// @brief virtual destructor
+    virtual ~CfgMgr();
+
+private:
+
+    /// @brief Checks if current configuration is created and creates it if needed.
+    ///
+    /// This private method is called to ensure that the current configuration
+    /// is created. If current configuration is not set, it creates the
+    /// default current configuration.
+    void ensureCurrentAllocated();
+
+
+    /// @brief Merges external configuration with the given sequence number
+    /// into the specified configuration.
+    ///
+    /// @param target_config Pointer to the configuration into which the
+    /// external configuration should be merged.
+    /// @param seq Source configuration sequence number.
+    void mergeIntoCfg(const SrvConfigPtr& taget_config, const uint32_t seq);
+
+    /// @brief directory where data files (e.g. server-id) are stored
+    util::Optional<std::string> datadir_;
+
+    /// @brief Manages the DHCP-DDNS client and its configuration.
+    D2ClientMgr d2_client_mgr_;
+
+    /// @brief Server configuration
+    ///
+    /// This is a structure that will hold all configuration.
+    /// @todo: migrate all other parameters to that structure.
+    SrvConfigPtr configuration_;
+
+    /// @name Configuration List.
+    ///
+    //@{
+    /// @brief Server configuration list type.
+    typedef std::list<SrvConfigPtr> SrvConfigList;
+
+    /// @brief Container holding all previous and current configurations.
+    SrvConfigList configs_;
+    //@}
+
+    /// @name Map of external configurations.
+    ///
+    //@{
+    /// @brief Server configuration map type.
+    typedef std::map<uint32_t, SrvConfigPtr> SrvConfigMap;
+
+    /// @brief Map of external configurations with sequence numbers used
+    /// as keys.
+    SrvConfigMap external_configs_;
+    //@}
+
+    /// @brief Address family.
+    uint16_t family_;
+};
+
+} // namespace isc::dhcp
+} // namespace isc
+
+#endif // CFGMGR_H