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| -rw-r--r-- | src/lib/dhcpsrv/cfg_subnets6.h | 359 |
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diff --git a/src/lib/dhcpsrv/cfg_subnets6.h b/src/lib/dhcpsrv/cfg_subnets6.h new file mode 100644 index 0000000..b21c808 --- /dev/null +++ b/src/lib/dhcpsrv/cfg_subnets6.h @@ -0,0 +1,359 @@ +// Copyright (C) 2014-2023 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 CFG_SUBNETS6_H +#define CFG_SUBNETS6_H + +#include <asiolink/io_address.h> +#include <dhcp/option.h> +#include <dhcp/pkt6.h> +#include <cc/cfg_to_element.h> +#include <dhcpsrv/cfg_shared_networks.h> +#include <dhcpsrv/subnet.h> +#include <dhcpsrv/subnet_id.h> +#include <dhcpsrv/subnet_selector.h> +#include <util/optional.h> +#include <boost/shared_ptr.hpp> +#include <string> + +namespace isc { +namespace dhcp { + +/// @brief Holds subnets configured for the DHCPv6 server. +/// +/// This class holds a collection of subnets configured for the DHCPv6 server. +/// It allows for retrieving a subnet for the particular client using various +/// parameters extracted from the DHCPv6 message. These parameters must be +/// assigned to the appropriate members of the @c SubnetSelector structure. +/// +/// See @c CfgSubnets6::selectSubnet documentation for more details on how the subnet +/// is selected for the client. +class CfgSubnets6 : public isc::data::CfgToElement { +public: + + /// @brief Adds new subnet to the configuration. + /// + /// @param subnet Pointer to the subnet being added. + /// + /// @throw isc::DuplicateSubnetID If the subnet id for the new subnet + /// duplicates id of an existing subnet. + void add(const Subnet6Ptr& subnet); + + /// @brief Replaces subnet in the configuration. + /// + /// This method replaces a subnet by another subnet with the same ID. + /// The prefix should be the same too. + /// + /// @param subnet Pointer to the subnet being updated. + /// @throw BadValue if the subnet to update does not exit. + /// @return Pointer to the replaced subnet or NULL if it failed. + Subnet6Ptr replace(const Subnet6Ptr& subnet); + + /// @brief Removes subnet from the configuration. + /// + /// @param subnet Pointer to the subnet to be removed. + /// + /// @throw isc::BadValue if such subnet doesn't exist. + void del(const ConstSubnet6Ptr& subnet); + + /// @brief Removes subnet from the configuration. + /// + /// @param subnet_id Identifier of the subnet to be removed. + /// + /// @throw isc::BadValue if such subnet doesn't exist. + void del(const SubnetID& subnet_id); + + /// @brief Merges specified subnet configuration into this configuration. + /// + /// This method merges subnets from the @c other configuration into this + /// configuration. The general rule is that existing subnets are replaced + /// by the subnets from @c other. If there is no corresponding subnet in + /// this configuration the subnet from @c other configuration is inserted. + /// + /// The complexity of the merge process stems from the associations between + /// the subnets and shared networks. It is assumed that subnets in @c other + /// are the authority on their shared network assignments. It is also + /// assumed that @ networks is the list of shared networks that should be + /// used in making assignments. The general concept is that the overarching + /// merge process will first merge shared networks and then pass that list + /// of networks into this method. Subnets from @c other are then merged + /// into this configuration as follows: + /// + /// For each subnet in @c other: + /// + /// - If a subnet of the same ID already exists in this configuration: + /// -# If it belongs to a shared network, remove it from that network + /// -# Remove the subnet from this configuration and discard it + /// + /// - Create the subnet's option instance, as well as any options + /// that belong to any of the subnet's pools. + /// - Add the subnet from @c other to this configuration. + /// - If that subnet is associated to shared network, find that network + /// in @ networks and add that subnet to it. + /// + /// @warning The merge operation affects the @c other configuration. + /// Therefore, the caller must not rely on the data held in the @c other + /// object after the call to @c merge. Also, the data held in @c other must + /// not be modified after the call to @c merge because it may affect the + /// merged configuration. + /// + /// @param cfg_def set of user-defined option definitions to use + /// when creating option instances. + /// @param networks collection of shared networks that to which assignments + /// should be added. In other words, the list of shared networks that belong + /// to the same SrvConfig instance we are merging into. + /// @param other the subnet configuration to be merged into this + /// configuration. + void merge(CfgOptionDefPtr cfg_def, CfgSharedNetworks6Ptr networks, + CfgSubnets6& other); + + /// @brief Returns pointer to the collection of all IPv6 subnets. + /// + /// This is used in a hook (subnet6_select), where the hook is able + /// to choose a different subnet. Server code has to offer a list + /// of possible choices (i.e. all subnets). + /// + /// @return A pointer to const Subnet6 collection + const Subnet6Collection* getAll() const { + return (&subnets_); + } + + /// @brief Returns const pointer to a subnet identified by the specified + /// subnet identifier. + /// + /// The const pointer is returned by this method to prevent a caller from + /// modifying the subnet configuration. Modifications to subnet configuration + /// is dangerous and must be done carefully. The subnets' configuration is + /// held in the multi index container and any modifications to the subnet + /// id or subnet prefix must trigger re-indexing of multi index container. + /// There is no possibility to enforce this when the non-const pointer is + /// returned. + /// + /// @param subnet_id Subnet identifier. + /// + /// @return Pointer to the @c Subnet6 object or null pointer if such + /// subnet doesn't exist. + ConstSubnet6Ptr getBySubnetId(const SubnetID& subnet_id) const; + + /// @brief Returns const pointer to a subnet which matches the specified + /// prefix in the canonical form. + /// + /// The const pointer is returned by this method to prevent a caller from + /// modifying the subnet configuration. Modifications to subnet configuration + /// is dangerous and must be done carefully. The subnets' configuration is + /// held in the multi index container and any modifications to the subnet + /// id or subnet prefix must trigger re-indexing of multi index container. + /// There is no possibility to enforce this when the non-const pointer is + /// returned. + /// + /// @param subnet_prefix Subnet prefix, e.g. 2001:db8:1::/64 + /// + /// @return Pointer to the @c Subnet6 object or null pointer if such + /// subnet doesn't exist. + ConstSubnet6Ptr getByPrefix(const std::string& subnet_prefix) const; + + /// @brief Build selector from a client's message. + /// + /// @note: code moved from server. + /// + /// @param query client's message. + /// @return filled selector. + static SubnetSelector initSelector(const Pkt6Ptr& query); + + /// @brief Selects a subnet using parameters specified in the selector. + /// + /// This method tries to retrieve the subnet for the client using various + /// parameters extracted from the client's message using the following + /// logic. + /// + /// If the relay agent link address is set to zero it is assumed that + /// the subnet is selected for the directly connected client. + /// In this case it is checked if there is any subnet associated with the + /// interface over which the message has been received. If there is no + /// subnet explicitly associated with this interface the client's address + /// will be used to check if the address is in range with any of the + /// subnets. + /// + /// If the message was relayed it is possible that the relay agent has + /// appended an Interface ID option. If this option is present, the method + /// will check if it matches with any explicitly specified interface id + /// for any subnet. If it does, the subnet is returned. Otherwise, the + /// relay agents link address is used to select the subnet. In this case, + /// the method will first check if this link address is explicitly + /// associated with any subnet. If not, it is checked if the link address + /// is in range with any of the subnets. + /// + /// @todo This method requires performance improvement! It currently + /// iterates over all existing subnets (possibly a couple of times) + /// to find the one which fulfills the search criteria. The subnet storage + /// is implemented as a simple STL vector which precludes fast searches + /// using specific keys. Hence, full scan is required. To improve the + /// search performance a different container type is required, e.g. + /// multi-index container, or something of a similar functionality. + /// + /// @param selector Const reference to the selector structure which holds + /// various information extracted from the client's packet which are used + /// to find appropriate subnet. + /// + /// @return Pointer to the selected subnet or NULL if no subnet found. + Subnet6Ptr selectSubnet(const SubnetSelector& selector) const; + + /// @brief Returns subnet with specified subnet-id value + /// + /// Warning: this method uses full scan. Its use is not recommended for + /// packet processing. + /// Please use @ref getBySubnetId instead when possible. + /// + /// @return Subnet (or NULL) + Subnet6Ptr getSubnet(const SubnetID id) const; + + /// @brief Selects the subnet using a specified address. + /// + /// This method searches for the subnet using the specified address. If + /// the specified address is a link address on the relay agent (which is + /// indicated by the 3rd argument) the method will first try to match the + /// specified address with the relay addresses explicitly specified for + /// existing subnets. If no match is found, the method will check if the + /// address is in range with any of the subnets. + /// + /// If the address is not a relay agent link address (@c is_relay_address + /// is set to false), the method will simply check if the address is in + /// range with any of the subnets. + /// + /// @note This method is mainly to be used in unit tests, which often + /// require sanity-checking if the subnet exists for the particular + /// address. For other purposes the @c selectSubnet(SubnetSelector) should + /// rather be used instead. + /// + /// @todo This method requires performance improvement! It currently + /// iterates over all existing subnets (possibly a couple of times) + /// to find the one which fulfills the search criteria. The subnet storage + /// is implemented as a simple STL vector which precludes fast searches + /// using specific keys. Hence, full scan is required. To improve the + /// search performance a different container type is required, e.g. + /// multi-index container, or something of a similar functionality. + /// + /// @param address Address for which the subnet is searched. + /// @param client_classes Optional parameter specifying the classes that + /// the client belongs to. + /// @param is_relay_address Specifies if the provided address is an + /// address of the relay agent (true) or not (false). + /// + /// @return Pointer to the selected subnet or NULL if no subnet found. + Subnet6Ptr + selectSubnet(const asiolink::IOAddress& address, + const ClientClasses& client_classes = ClientClasses(), + const bool is_relay_address = false) const; + + /// @brief Convert a link address into a link set. + /// + /// Given a link address this returns the ordered list aka set of id + /// of subnets the address belongs to. It also sets the minimum link + /// length when there is at least one subnet. + /// + /// @param link_addr The link address. + /// @param[out] link_len The minimum link length. + /// @return The set of subnet ids the link address belongs to. + SubnetIDSet getLinks(const asiolink::IOAddress& link_addr, + uint8_t& link_len) const; + + /// @brief Updates statistics. + /// + /// This method updates statistics that are affected by the newly committed + /// configuration. In particular, it updates the number of available addresses + /// and prefixes in each subnet. Other statistics may be added in the future. In + /// general, these are statistics that are dependent only on configuration, so + /// they are not expected to change until the next reconfiguration event. + void updateStatistics(); + + /// @brief Removes statistics. + /// + /// During commitment of a new configuration, we need to get rid of the old + /// statistics for the old configuration. In particular, we need to remove + /// anything related to subnets, as there may be fewer subnets in the new + /// configuration and also subnet-ids may change. + void removeStatistics(); + + /// @brief Calls @c initAllocatorsAfterConfigure for each subnet. + void initAllocatorsAfterConfigure(); + + /// @brief Clears all subnets from the configuration. + void clear(); + + /// @brief Unparse a configuration object + /// + /// @return a pointer to unparsed configuration + virtual isc::data::ElementPtr toElement() const; + +private: + + /// @brief Selects a subnet using the interface name. + /// + /// This method searches for the subnet using the name of the interface. + /// If any of the subnets is explicitly associated with the interface + /// name, the subnet is returned. + /// + /// @todo This method requires performance improvement! It currently + /// iterates over all existing subnets to find the one which fulfills + /// the search criteria. The subnet storage is implemented as a + /// simple STL vector which precludes fast searches using specific + /// keys. Hence, full scan is required. To improve the search + /// performance a different container type is required, e.g. + /// multi-index container, or something of a similar functionality. + /// + /// @param iface_name Interface name. + /// @param client_classes Optional parameter specifying the classes that + /// the client belongs to. + /// + /// @return Pointer to the selected subnet or NULL if no subnet found. + Subnet6Ptr + selectSubnet(const std::string& iface_name, + const ClientClasses& client_classes) const; + + /// @brief Selects a subnet using Interface ID option. + /// + /// This method searches for the subnet using the Interface ID option + /// inserted by the relay agent to the message from a client. If any + /// of the subnets is explicitly associated with that interface id, the + /// subnet is returned. + /// + /// @todo This method requires performance improvement! It currently + /// iterates over all existing subnets to find the one which fulfills + /// the search criteria. The subnet storage is implemented as a + /// simple STL vector which precludes fast searches using specific + /// keys. Hence, full scan is required. To improve the search + /// performance a different container type is required, e.g. + /// multi-index container, or something of a similar functionality. + /// + /// @param interface_id An instance of the Interface ID option received + /// from the client. + /// @param client_classes Optional parameter specifying the classes that + /// the client belongs to. + /// + /// @return Pointer to the selected subnet or NULL if no subnet found. + Subnet6Ptr + selectSubnet(const OptionPtr& interface_id, + const ClientClasses& client_classes) const; + + /// @brief A container for IPv6 subnets. + Subnet6Collection subnets_; + +}; + +/// @name Pointer to the @c CfgSubnets6 objects. +//@{ +/// @brief Non-const pointer. +typedef boost::shared_ptr<CfgSubnets6> CfgSubnets6Ptr; + +/// @brief Const pointer. +typedef boost::shared_ptr<const CfgSubnets6> ConstCfgSubnets6Ptr; + +//@} + +} +} + +#endif // CFG_SUBNETS6_H |