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// Copyright (C) 2014-2016 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_SUBNETS4_H
#define CFG_SUBNETS4_H
#include <asiolink/io_address.h>
#include <dhcpsrv/subnet.h>
#include <dhcpsrv/subnet_selector.h>
#include <boost/shared_ptr.hpp>
namespace isc {
namespace dhcp {
/// @brief Holds subnets configured for the DHCPv4 server.
///
/// This class holds a collection of subnets configured for the DHCPv4 server.
/// It allows for retrieving a subnet for the particular client using various
/// parameters extracted from the DHCPv4 message. These parameters must be
/// assigned to the appropriate members of the @c CfgSubnets4::Selector
/// structure.
///
/// See @c CfgSubnets4::selectSubnet documentation for more details on how the
/// subnet is selected for the client.
class CfgSubnets4 {
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 Subnet4Ptr& subnet);
/// @brief Returns pointer to the collection of all IPv4 subnets.
///
/// This is used in a hook (subnet4_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 Subnet4 collection
const Subnet4Collection* getAll() const {
return (&subnets_);
}
/// @brief Returns a pointer to the selected subnet.
///
/// This method tries to retrieve the subnet for the client using various
/// parameters extracted from the client's message using the following
/// logic.
///
/// First when link select suboption of relay agent information option
/// or subnet select option in this order exists the address is used
///
/// If the giaddr value is set in the selector it means that the client's
/// message was relayed. The subnet configuration allows for setting the
/// relay address for each subnet to indicate that the subnet must be
/// assigned when the packet was transmitted over the particular relay.
/// This method first tries to match the giaddr with the relay addresses
/// specified for all subnets. If the relay address for the subnet is equal
/// to the address of the relay through which the message was transmitted,
/// the particular subnet is returned.
///
/// If the giaddr is not matched with any of the relay addresses in any
/// subnet or the message was not relayed, the method will need to try to
/// match one of the addresses in the client's message with the prefixes
/// of the existing subnets. Depending whether it is a relayed message,
/// message from the renewing client or a new allocation, the server will
/// pick one of the following addresses for this matching:
/// - giaddr - for relayed message
/// - ciaddr - for renewing or rebinding client
/// - source address - for the renewing client which didn't provide ciaddr
/// - address on the local server's interface if this is a new allocation
/// requested by the directly connected client
///
/// If the address matches with a subnet, the subnet is returned.
///
/// @todo This method requires performance improvement! It currently
/// iterates over all existing subnets (possibly a couple of times)
/// to find the one which fulfils 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.
/// @throw isc::BadValue if the values in the subnet selector are invalid
/// or they are insufficient to select a subnet.
Subnet4Ptr selectSubnet(const SubnetSelector& selector) const;
/// @brief Returns a pointer to a subnet if provided address is in its range.
///
/// This method returns a pointer to the subnet if the address passed in
/// parameter is in range with this subnet. This is mainly used for unit
/// testing. This method is also called by the
/// @c selectSubnet(SubnetSelector).
///
/// @todo This method requires performance improvement! It currently
/// iterates over all existing subnets to find the one which fulfils
/// 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.
///
/// @return Pointer to the selected subnet or NULL if no subnet found.
Subnet4Ptr selectSubnet(const asiolink::IOAddress& address,
const ClientClasses& client_classes
= ClientClasses()) const;
/// @brief Returns a pointer to a subnet if provided interface name matches.
///
/// This method returns a pointer to the subnet if the interface name passed
/// in parameter iface matches that of a subnet. This is mainly used for matching
/// local incoming traffic, even when the addresses on local interfaces do
/// not match a subnet definition. This method is also called by the
/// @c selectSubnet(SubnetSelector).
///
/// @todo This method requires performance improvement! It currently
/// iterates over all existing subnets to find the one which fulfils
/// 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 of the interface to be matched.
/// @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.
Subnet4Ptr selectSubnet(const std::string& iface,
const ClientClasses& client_classes) const;
/// @brief Attempts to do subnet selection based on DHCP4o6 information
///
/// The algorithm implemented is as follows:
///
/// - First: try to match IPv6 subnet (4o6-subnet parameter) with the
/// remote IPv6 address of the incoming packet
/// - Second: try to match interface-id (4o6-interface-id parameter)
/// with the interface-id option in the incoming 4o6 packet
/// - Third: try to match interface-name (4o6-interface parameter)
/// with the name of the interface the incoming 4o6 packet was
/// received over.
///
/// @todo: Add additional selection criteria. See
/// http://kea.isc.org/wiki/ISC-DHCP4o6-Design for details.
///
/// @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.
Subnet4Ptr
selectSubnet4o6(const SubnetSelector& selector) 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
/// in each subnet. Other statistics may be added in the future. In general,
/// these are statistics that are dependant 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();
private:
/// @brief Checks that the IPv4 subnet with the given id already exists.
///
/// @param subnet Subnet for which this function will check if the other
/// subnet with equal id already exists.
///
/// @return true if the duplicate subnet exists.
bool isDuplicate(const Subnet4& subnet) const;
/// @brief A container for IPv4 subnets.
Subnet4Collection subnets_;
};
/// @name Pointer to the @c CfgSubnets4 objects.
//@{
/// @brief Non-const pointer.
typedef boost::shared_ptr<CfgSubnets4> CfgSubnets4Ptr;
/// @brief Const pointer.
typedef boost::shared_ptr<const CfgSubnets4> ConstCfgSubnets4Ptr;
//@}
}
}
#endif // CFG_SUBNETS4_H
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