Top ports - introduce TopPorts class

Author: Zadamsa

src/plugins/input/parser/CMakeLists.txt

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+add_library(top-ports STATIC
+	topPorts.cpp
+	topPorts.hpp
+)
+
+target_include_directories(top-ports PUBLIC
+	${CMAKE_SOURCE_DIR}/include
+	${CMAKE_BINARY_DIR}/src
+)
+
+target_compile_options(top-ports PRIVATE -fPIC)

src/plugins/input/parser/topPorts.cpp

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+/**
+ * \file topPorts.cpp
+ * \brief TopPorts class implementation.
+ * \author Damir Zainullin <[email protected]>
+ * \date 2024
+ */
+
+#include "topPorts.hpp"
+
+#include <algorithm>
+#include <array>
+#include <cstdint>
+#include <functional>
+#include <limits>
+#include <string>
+#include <vector>
+
+namespace ipxp {
+
+TopPorts::TopPorts(size_t top_ports_count) noexcept
+	: m_top_ports_count(top_ports_count)
+{
+}
+
+std::string TopPorts::PortStats::to_string() const noexcept
+{
+	return std::to_string(port) + "[" + (protocol == Protocol::TCP ? "TCP" : "UDP") + "] - "
+		+ std::to_string(frequency);
+}
+
+bool update_port_buffer(
+	std::vector<TopPorts::PortStats>& port_buffer,
+	TopPorts::PortStats port_stats) noexcept
+{
+	auto port_pos = std::lower_bound(
+		port_buffer.begin(),
+		port_buffer.end(),
+		port_stats.frequency,
+		[](const TopPorts::PortStats& port_frequency, size_t count) {
+			return port_frequency.frequency >= count;
+		});
+
+	if (port_pos != port_buffer.end()) {
+		std::copy_backward(port_pos, std::prev(port_buffer.end()), port_buffer.end());
+		*port_pos = port_stats;
+		return true;
+	}
+	return false;
+};
+
+std::vector<TopPorts::PortStats> TopPorts::get_top_ports() const noexcept
+{
+	std::vector<PortStats> port_buffer(m_top_ports_count);
+	size_t ports_inserted = 0;
+
+	std::for_each(
+		m_tcp_port_frequencies.begin(),
+		m_tcp_port_frequencies.end(),
+		[&, port = uint16_t {0}](size_t frequency) mutable {
+			ports_inserted
+				+= update_port_buffer(port_buffer, {port++, frequency, PortStats::Protocol::TCP});
+		});
+	std::for_each(
+		m_udp_port_frequencies.begin(),
+		m_udp_port_frequencies.end(),
+		[&, port = uint16_t {0}](size_t frequency) mutable {
+			ports_inserted
+				+= update_port_buffer(port_buffer, {port++, frequency, PortStats::Protocol::UDP});
+		});
+
+	port_buffer.resize(std::min(m_top_ports_count, ports_inserted));
+	return port_buffer;
+}
+
+} // namespace ipxp

src/plugins/input/parser/topPorts.hpp

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+/**
+ * \file topPorts.hpp
+ * \brief TopPorts class declaration implementing the most popular ports.
+ * \author Damir Zainullin <[email protected]>
+ * \date 2024
+ */
+#pragma once
+
+#include <array>
+#include <cstdint>
+#include <limits>
+#include <string>
+#include <vector>
+
+namespace ipxp {
+/**
+ * \brief Top ports counter.
+ */
+class TopPorts {
+public:
+	/**
+	 * \brief Constructor.
+	 * \param top_ports_count Number of the most popular ports to track.
+	 */
+	TopPorts(size_t top_ports_count) noexcept;
+
+	/**
+	 * \brief Increments number of times given tcp port has been seen.
+	 * \param port Port to increment its frequency.
+	 */
+	void increment_tcp_frequency(uint16_t port) noexcept { m_tcp_port_frequencies[port]++; }
+
+	/**
+	 * \brief Increments number of times given udp port has been seen.
+	 * \param port Port to increment its frequency.
+	 */
+	void increment_udp_frequency(uint16_t port) noexcept { m_udp_port_frequencies[port]++; }
+
+	/**
+	 * \brief Port frequency and protocol to which it belongs.
+	 */
+	struct PortStats {
+		/**
+		 * \brief Protocol type.
+		 */
+		enum class Protocol { TCP, UDP };
+
+		uint16_t port; /**< Port number. */
+		size_t frequency; /**< Number of times the port has been seen. */
+		Protocol protocol; /**< Protocol to which the port belongs. */
+
+		/**
+		 * \brief Convert the port stats to string.
+		 * \return String representation of the port stats.
+		 */
+		std::string to_string() const noexcept;
+	};
+
+	/**
+	 * \brief Get the top ports.
+	 * \return Vector of the most popular ports.
+	 */
+	std::vector<TopPorts::PortStats> get_top_ports() const noexcept;
+
+private:
+	std::array<std::size_t, std::numeric_limits<uint16_t>::max() + 1> m_tcp_port_frequencies {};
+	std::array<std::size_t, std::numeric_limits<uint16_t>::max() + 1> m_udp_port_frequencies {};
+	const size_t m_top_ports_count;
+};
+
+} // namespace ipxp