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kea/src/lib/dhcp/classify.h
2025-08-20 19:43:25 +02:00

287 lines
8.8 KiB
C++

// Copyright (C) 2014-2025 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 CLASSIFY_H
#define CLASSIFY_H
#include <cc/data.h>
#include <cc/cfg_to_element.h>
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/member.hpp>
#include <boost/multi_index/hashed_index.hpp>
#include <boost/multi_index/identity.hpp>
#include <boost/multi_index/ordered_index.hpp>
#include <boost/multi_index/sequenced_index.hpp>
#include <string>
#include <functional>
/// @file classify.h
///
/// @brief Defines elements for storing the names of client classes
///
/// This file defines common elements used to track the client classes
/// that may be associated with a given packet. In order to minimize the
/// exposure of the DHCP library to server side concepts such as client
/// classification the classes herein provide a mechanism to maintain lists
/// of class names, rather than the classes they represent. It is the
/// upper layers' prerogative to use these names as they see fit.
///
/// @todo This file should be moved to dhcpsrv eventually as the classification
/// is server side concept. Client has no notion of classifying incoming server
/// messages as it usually talks to only one server. That move is not possible
/// yet, as the Pkt4 and Pkt6 classes have server-side implementation, even
/// though they reside in the dhcp directory.
namespace isc {
namespace dhcp {
/// @brief Defines a single class name.
typedef std::string ClientClass;
/// @brief Tag for the sequence index.
struct ClassSequenceTag { };
/// @brief Tag for the name index.
struct ClassNameTag { };
/// @brief the client class multi-index.
typedef boost::multi_index_container<
ClientClass,
boost::multi_index::indexed_by<
// First index is the sequence one.
boost::multi_index::sequenced<
boost::multi_index::tag<ClassSequenceTag>
>,
// Second index is the name hash one.
boost::multi_index::hashed_unique<
boost::multi_index::tag<ClassNameTag>,
boost::multi_index::identity<ClientClass>
>
>
> ClientClassContainer;
/// @brief Defines a subclass to template class relation.
struct SubClassRelation {
/// @brief Constructor.
SubClassRelation(const ClientClass& class_def, const ClientClass& subclass) :
class_def_(class_def), class_(subclass) {
}
/// @brief The class definition name.
ClientClass class_def_;
/// @brief The class or subclass name.
ClientClass class_;
};
/// @brief Tag for the sequence index.
struct TemplateClassSequenceTag { };
/// @brief Tag for the name index.
struct TemplateClassNameTag { };
/// @brief the subclass multi-index.
typedef boost::multi_index_container<
SubClassRelation,
boost::multi_index::indexed_by<
// First index is the sequence one.
boost::multi_index::sequenced<
boost::multi_index::tag<TemplateClassSequenceTag>
>,
// Second index is the name hash one.
boost::multi_index::hashed_unique<
boost::multi_index::tag<TemplateClassNameTag>,
boost::multi_index::member<SubClassRelation,
ClientClass,
&SubClassRelation::class_def_>
>
>
> SubClassRelationContainer;
/// @brief Container for storing client class names
///
/// Both a list to iterate on it in insert order and unordered
/// set of names for existence.
class ClientClasses : public isc::data::CfgToElement {
public:
/// @brief Type of iterators
typedef ClientClassContainer::const_iterator const_iterator;
typedef ClientClassContainer::iterator iterator;
/// @brief Default constructor.
ClientClasses() : container_() {
}
/// @brief Constructor from comma separated values.
///
/// @param class_names A string containing a client classes separated
/// with commas. The class names are trimmed before insertion to the set.
ClientClasses(const std::string& class_names);
/// @brief Destructor.
virtual ~ClientClasses() {}
/// @brief Copy constructor.
///
/// @param other ClientClasses object to be copied.
ClientClasses(const ClientClasses& other);
/// @brief Assigns the contents of on container to another.
ClientClasses& operator=(const ClientClasses& other);
/// @brief Compares two ClientClasses container for equality
///
/// @return True if the two containers are equal, false otherwise.
bool equals(const ClientClasses& other) const;
/// @brief Compares two ClientClasses containers for equality.
///
/// @return True if the two containers are equal, false otherwise.
bool operator==(const ClientClasses& other) const {
return(equals(other));
}
/// @brief Compares two ClientClasses container for inequality
///
/// @return True if the two containers are not equal, false otherwise.
bool operator!=(const ClientClasses& other) const {
return(!equals(other));
}
/// @brief Insert an element.
///
/// @param class_name The name of the class to insert
void insert(const ClientClass& class_name) {
static_cast<void>(container_.push_back(class_name));
}
/// @brief Erase element by name.
///
/// @param class_name The name of the class to erase.
void erase(const ClientClass& class_name);
/// @brief Check if classes is empty.
bool empty() const {
return (container_.empty());
}
/// @brief Returns the number of classes.
///
/// @note; in C++ 11 list size complexity is constant so
/// there is no advantage to use the set part.
size_t size() const {
return (container_.size());
}
/// @brief Iterators to the first element.
/// @{
const_iterator cbegin() const {
return (container_.cbegin());
}
const_iterator begin() const {
return (container_.begin());
}
iterator begin() {
return (container_.begin());
}
/// @}
/// @brief Iterators to the past the end element.
/// @{
const_iterator cend() const {
return (container_.cend());
}
const_iterator end() const {
return (container_.end());
}
iterator end() {
return (container_.end());
}
/// @}
/// @brief returns whether this container has at least one class
/// in common with a given container.
///
/// @param cclasses list of classes to check for intersection with
/// @return true if this container has at least one class that is
/// also in cclasses, false otherwise.
bool intersects(const ClientClasses& cclasses) const;
/// @brief returns if class x belongs to the defined classes
///
/// @param x client class to be checked
/// @return true if x belongs to the classes
bool contains(const ClientClass& x) const;
/// @brief Clears containers.
void clear() {
container_.clear();
}
/// @brief Returns all class names as text
///
/// @param separator Separator to be used between class names. The
/// default separator comprises comma sign followed by space
/// character.
///
/// @return the string representation of all classes
std::string toText(const std::string& separator = ", ") const;
/// @brief Returns all class names as an ElementPtr of type ListElement
///
/// @return the list
virtual isc::data::ElementPtr toElement() const;
/// @brief Sets contents from a ListElement
///
/// @param list JSON list of classes from which to populate
/// the container.
///
/// @throw BadValue if the element is not a list or contents
/// are invalid
void fromElement(isc::data::ConstElementPtr list);
/// @brief Hash enabling use in the unordered containers.
struct Hash {
/// @brief A hashing operator.
///
/// @param client_classes ClientClasses instance to be hashed.
/// @return a hashing result.
size_t operator()(const ClientClasses& client_classes);
};
private:
/// @brief container part
ClientClassContainer container_;
};
/// @brief Hash a ClientClasses instance.
///
/// This method allows boost multi-index hashed indexes on ClientClasses.
/// It follows the requirement with equality: if two class lists are equal
/// their hashes are equal, if two class lists are not equal their hashes
/// are almost surely not equal.
///
/// @param client_classes A @c ClientClasses to hash.
/// @return The hash of the ClientClasses.
size_t hash_value(const ClientClasses& client_classes);
/// @brief Smart pointer to ClientClasses object.
typedef boost::shared_ptr<ClientClasses> ClientClassesPtr;
}
}
#endif /* CLASSIFY_H */