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WIF - Utils - Introduce IP prefix
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‎include/wif/utils/ipPrefix.hpp‎

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/**
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* @file
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* @author Richard Plny <[email protected]>
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* @brief IP prefix interface
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* Based on:
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* https://github.com/CESNET/nemea-modules-ng/blob/main/modules/whitelist/src/ipAddressPrefix.hpp
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#pragma once
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#include "wif/storage/ipAddress.hpp"
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namespace WIF {
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/**
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* @brief Class representing an IP prefix (or an IP subnet)
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*/
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class IpPrefix {
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public:
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/**
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* @brief Max bit lenth of IPv4 prefix
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*/
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static constexpr size_t IPV4_MAX_PREFIX_LENGTH = 32;
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/**
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* @brief Max bit lenth of IPv6 prefix
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*/
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static constexpr size_t IPV6_MAX_PREFIX_LENGTH = 128;
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/**
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* @brief Construct a new IP Prefix object representing just 1 IP address
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*
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* @param address single IP address
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*/
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IpPrefix(const IpAddress& address);
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/**
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* @brief Construct a new IP Prefix object
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* @param addressStr string representation of IP prefix
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* @param prefixLength number of bits of the prefix
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*/
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IpPrefix(const std::string& addressStr, size_t prefixLength);
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/**
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* @brief Construct a new IP Prefix object
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* @param address IP prefix
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* @param prefixLength number of bits of the prefix
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*/
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IpPrefix(const IpAddress& address, size_t prefixLength);
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/**
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* @brief Getter for the number of bits used by prefix
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* @return size_t number of bits of the prefix
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*/
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size_t prefixLength() const noexcept { return m_prefixLength; }
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/**
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* @brief Getter for number of IP addresses in the prefix
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* @return size_t number of IP addresses in the prefix
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*/
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size_t size() const noexcept;
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/**
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* @brief Getter for the prefix address
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* @return const IpAddress& prefix address
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*/
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const IpAddress& getPrefix() const noexcept { return m_prefixAddress; }
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/**
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* @brief Getter for the prefix mask
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* @return const IpAddress& prefix mask
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*/
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const IpAddress& getMask() const noexcept { return m_prefixMask; }
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/**
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* @brief Match IP prefix and check if IP address in part of the prefix
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* @param ipAddress to be matched
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* @return true if ipAddress is in this prefix
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* @return false otherwise
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*/
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bool match(const IpAddress& ipAddress) const noexcept;
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/**
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* @brief Comparison operator <
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* @param l left operand
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* @param r right operand
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* @return bool true if l is less than r
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*/
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friend bool operator<(const IpPrefix& l, const IpPrefix& r);
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/**
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* @brief Comparison operator <
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* Used for binary search of IP address in a vector of IP prefixes
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* @param l left operand
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* @param r right operand
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* @return bool true if l is less than r
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*/
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friend bool operator<(const IpAddress& l, const IpPrefix& r);
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/**
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* @brief Comparison operator <
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* Used for binary search of IP address in a vector of IP prefixes
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* @param l left operand
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* @param r right operand
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* @return bool true if l is less than r
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*/
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friend bool operator<(const IpPrefix& l, const IpAddress& r);
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private:
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IpAddress m_prefixAddress;
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IpAddress m_prefixMask;
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size_t m_prefixLength;
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};
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} // namespace WIF

‎src/wif/CMakeLists.txt‎

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regex/regexPattern.cpp
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storage/flowFeatures.cpp
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storage/ipAddress.cpp
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utils/ipPrefix.cpp
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)
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set(LIBWIF_LIBS

‎src/wif/utils/ipPrefix.cpp‎

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/**
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* @file
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* @author Richard Plny <[email protected]>
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* @brief IP prefix implementation
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include "wif/utils/ipPrefix.hpp"
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#include <climits>
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#include <cmath>
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#include <cstdint>
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#include <limits>
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namespace {
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void validatePrefixLength(size_t prefixLength, size_t maxPrefixLength)
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{
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if (prefixLength > maxPrefixLength) {
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throw std::invalid_argument(
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"IP prefix is too long. Given: " + std::to_string(prefixLength)
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+ ", max: " + std::to_string(maxPrefixLength));
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}
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}
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WIF::IpAddress createIpV6MaskFromPrefix(size_t prefixLength)
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{
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uint8_t prefixBytes = prefixLength / 8;
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uint8_t prefixBits = prefixLength % 8;
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uint8_t data[16];
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for (unsigned bytesIndex = 0; bytesIndex < prefixBytes; ++bytesIndex) {
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data[bytesIndex] = UINT8_MAX;
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}
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if (prefixBits != 0U) {
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data[prefixBytes] = UINT8_MAX << (CHAR_BIT - prefixBits);
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}
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return WIF::IpAddress(data, WIF::IpAddress::IpVersion::V6);
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}
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} // namespace
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namespace WIF {
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IpPrefix::IpPrefix(const IpAddress& address)
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: IpPrefix(address, address.isIPv4() ? IPV4_MAX_PREFIX_LENGTH : IPV6_MAX_PREFIX_LENGTH)
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{
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}
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IpPrefix::IpPrefix(const std::string& addressStr, size_t prefixLength)
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: IpPrefix(IpAddress(addressStr), prefixLength)
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{
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}
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IpPrefix::IpPrefix(const IpAddress& address, size_t prefixLength)
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: m_prefixLength(prefixLength)
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{
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if (address.isIPv4()) {
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validatePrefixLength(prefixLength, IPV4_MAX_PREFIX_LENGTH);
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size_t shift = IPV4_MAX_PREFIX_LENGTH - prefixLength;
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m_prefixMask = IpAddress(std::numeric_limits<uint32_t>::max() << shift);
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} else {
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validatePrefixLength(prefixLength, IPV6_MAX_PREFIX_LENGTH);
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m_prefixMask = createIpV6MaskFromPrefix(prefixLength);
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}
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m_prefixAddress = address & m_prefixMask;
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}
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size_t IpPrefix::size() const noexcept
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{
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if (m_prefixAddress.isIPv4()) {
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return std::pow(2, IPV4_MAX_PREFIX_LENGTH - m_prefixLength);
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} else {
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return std::pow(2, IPV6_MAX_PREFIX_LENGTH - m_prefixLength);
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}
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}
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bool IpPrefix::match(const IpAddress& ipAddress) const noexcept
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{
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if (ipAddress.getVersion() != m_prefixAddress.getVersion()) {
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return false;
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}
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return (ipAddress & m_prefixMask) == m_prefixAddress;
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}
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bool operator<(const IpPrefix& l, const IpPrefix& r)
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{
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// IPv4 is before IPv6
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if (l.m_prefixAddress.isIPv4() && r.m_prefixAddress.isIPv6()) {
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return true;
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} else if (l.m_prefixAddress.isIPv6() && r.m_prefixAddress.isIPv4()) {
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return false;
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} // Now we are sure that both prefixes have the same IP version
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if (l.m_prefixAddress == r.m_prefixAddress) {
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return l.m_prefixLength < r.m_prefixLength;
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}
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return l.m_prefixAddress < r.m_prefixAddress;
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}
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bool operator<(const IpAddress& l, const IpPrefix& r)
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{
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return l < r.m_prefixAddress;
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}
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bool operator<(const IpPrefix& l, const IpAddress& r)
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{
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return l.m_prefixAddress < r;
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}
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} // namespace WIF

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