TCP - Craete C++ epoll wrapper

Author: BonnyAD9

src/plugins/input/tcp/CMakeLists.txt

@@ -5,6 +5,7 @@ add_library(tcp-input MODULE
     src/ByteVector.cpp
     src/DecodeBuffer.cpp
     src/Connection.cpp
+    src/Epoll.cpp
 )
 
 if (CMAKE_HOST_SYSTEM_NAME STREQUAL "FreeBSD" OR CMAKE_HOST_SYSTEM_NAME STREQUAL "OpenBSD")

src/plugins/input/tcp/src/Epoll.cpp

@@ -0,0 +1,59 @@
+/**
+ * \file
+ * \author Jakub Antonín Štigler <[email protected]>
+ * \brief C++ wrapper around epoll (source file)
+ * \date 2024
+ *
+ * Copyright: (C) 2023 CESNET, z.s.p.o.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include "Epoll.hpp"
+
+#include <stdexcept> // runtime_error
+#include <cerrno>    // errno, EINTR
+#include <string>    // string
+
+#include <sys/epoll.h> // epoll_event, epoll_create, EPOLLIN, EPOLL_CT_ADD, epoll_ctl, EPOLL_CTL_DEL
+
+#include <ipfixcol2.h> // ipx_strerror
+
+#include "UniqueFd.hpp" // UniqueFd
+
+namespace tcp_in {
+
+Epoll::Epoll() : m_fd(epoll_create(1)) {
+    if (!m_fd) {
+        const char *err_str;
+        ipx_strerror(errno, err_str);
+        throw std::runtime_error("Failed to create epoll: " + std::string(err_str));
+    }
+}
+
+void Epoll::add(int fd, void *data) {
+    epoll_event ev;
+    ev.events = EPOLLIN;
+    if (data) {
+        ev.data.ptr = data;
+    } else {
+        ev.data.fd = fd;
+    }
+    if (epoll_ctl(m_fd.get(), EPOLL_CTL_ADD, fd, &ev) == -1) {
+        const char *err_str;
+        ipx_strerror(errno, err_str);
+        throw std::runtime_error("Failed to add to epoll: " + std::string(err_str));
+    }
+}
+
+int Epoll::wait(epoll_event *events, int max_events, int timeout) {
+    int ev_valid = epoll_wait(m_fd.get(), events, max_events, timeout);
+    if (ev_valid == -1) {
+        if (errno == EINTR) {
+            return 0;
+        }
+    }
+
+    return ev_valid;
+}
+
+} // namespace tcp_in

src/plugins/input/tcp/src/Epoll.hpp

@@ -0,0 +1,58 @@
+/**
+ * \file
+ * \author Jakub Antonín Štigler <[email protected]>
+ * \brief C++ wrapper around epoll (header file)
+ * \date 2024
+ *
+ * Copyright: (C) 2023 CESNET, z.s.p.o.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#pragma once
+
+#include <sys/epoll.h> // epoll_event
+
+#include "UniqueFd.hpp" // UniqueFd
+
+namespace tcp_in {
+
+class Epoll {
+public:
+    /**
+     * @brief Craetes empty epoll.
+     * @throws when fails to create epoll.
+     */
+    Epoll();
+
+    /**
+     * @brief Add file descriptor to the epoll.
+     * @param fd File descriptor to add.
+     * @param [in] data data asociated with the file descriptor, when null, descriptor is set as
+     * data
+     * @throws when fails to add to the epoll.
+     */
+    void add(int fd, void *data);
+
+    /**
+     * @brief Waits for any of the file descriptors in the epoll to be active.
+     * @param[out] ev store all active descriptors here
+     * @param max_events max number of events to store in `events`
+     * @param timeout maximum time to wait in milliseconds, -1 for infinite wait
+     * @returns Number of events written to `events`, negative on error (errno is set)
+     */
+    int wait(epoll_event *events, int max_events, int timeout = -1);
+
+    /**
+     * @brief Removes file descriptor from the epoll.
+     * @param fd File descriptor to remove from the epoll.
+     * @return true on success, otherwise false
+     */
+    bool remove(int fd) noexcept {
+        return epoll_ctl(m_fd.get(), EPOLL_CTL_DEL, fd, nullptr) == 0;
+    }
+
+private:
+    UniqueFd m_fd;
+};
+
+} // namespace tcp_in