Move functions to detail namespace

CMakeLists.txt

@@ -43,7 +43,7 @@ FetchContent_MakeAvailable(googletest)
 #
 
 
-add_executable(playground src/main.cpp src/tcp.cpp)
+add_executable(playground src/main.cpp src/tcp_server.cpp src/tcp_client.cpp)
 target_link_libraries(playground PRIVATE spdlog::spdlog)
 
 
@@ -54,25 +54,28 @@ target_link_libraries(playground PRIVATE spdlog::spdlog)
 #
 
 
+include(GoogleTest)
+
 
 enable_testing()
 
-add_executable(
+add_executable(tcp_blocking_test
-    tcp_test
+    tests/tcp_blocking.cpp
-    tests/tcp.cpp
+    src/tcp_server.cpp
-    src/tcp.cpp
+    src/tcp_client.cpp
-)
-target_link_libraries(
-  tcp_test
-  spdlog::spdlog
-  GTest::gtest_main
-)
-target_include_directories(
-  tcp_test
-  PRIVATE
-  src
 )
+target_link_libraries(tcp_blocking_test spdlog::spdlog GTest::gtest_main)
+target_include_directories(tcp_blocking_test PRIVATE src)
 
-include(GoogleTest)
+gtest_discover_tests(tcp_blocking_test)
-gtest_discover_tests(tcp_test)
+
+add_executable(tcp_non_blocking_test
+    tests/tcp_non_blocking.cpp
+    src/tcp_server.cpp
+    src/tcp_client.cpp
+)
+target_link_libraries(tcp_non_blocking_test spdlog::spdlog GTest::gtest_main)
+target_include_directories(tcp_non_blocking_test PRIVATE src)
+
+gtest_discover_tests(tcp_non_blocking_test)
 

src/common.hpp

@@ -0,0 +1,54 @@
+#pragma once
+
+
+// STL includes
+#include <expected>
+
+// C stdlib includes
+#include <netdb.h>
+#include <netinet/in.h>
+
+// Library includes
+#include <spdlog/spdlog.h>
+
+
+namespace tcp {
+
+
+namespace detail {
+
+
+inline std::expected<sockaddr_in, int> resolve_remote_address(const char* host,
+                                                              uint16_t port) {
+    hostent* server = gethostbyname(host);
+    if (server == nullptr) {
+        spdlog::error("tcp: get_host_by_name() failed with h_errno={}",
+                      h_errno);
+        return std::unexpected{h_errno};
+    }
+
+    sockaddr_in address{};
+    address.sin_family = AF_INET;
+    address.sin_port   = htons(port);
+    bcopy((char*)server->h_addr, (char*)&address.sin_addr.s_addr,
+          server->h_length);
+
+    return address;
+}
+
+inline sockaddr_in get_local_address(uint16_t port) {
+    sockaddr_in address{};
+    address.sin_addr.s_addr = htonl(INADDR_ANY);
+    address.sin_family      = AF_INET;
+    address.sin_port        = htons(port);
+    return address;
+}
+
+
+} // namespace detail
+
+
+using HostString = std::array<char, 64>;
+
+
+} // namespace tcp

src/main.cpp

@@ -1,12 +1,15 @@
-#include "tcp.hpp"
+// Library includes
-#include <cstddef>
 #include <spdlog/spdlog.h>
 
+// Project includes
+#include "tcp_server.hpp"
+
+
 int main() {
     spdlog::set_level(spdlog::level::debug);
 
-    tcp::NonBlockingServer server{{.port = 65432}};
+    tcp::NonBlockingServer server{};
-    if (auto res = server.start_listening(); !res) {
+    if (auto res = server.start_listening(65432); !res) {
         spdlog::error("Failed to start server: {}", res.error());
         return 1;
     }
@@ -47,6 +50,6 @@ int main() {
             spdlog::info("Sent {} bytes", sendRes.value());
         }
 
-        server.disconnect();
+        server.disconnect_from_client();
     }
 }

src/tcp.hpp

@@ -1,120 +0,0 @@
-#pragma once
-
-
-#include <array>
-#include <cerrno>
-#include <cstdint>
-#include <expected>
-#include <poll.h>
-#include <span>
-#include <spdlog/spdlog.h>
-#include <sys/socket.h>
-
-// C stdlib includes
-#include <arpa/inet.h>
-#include <expected>
-#include <fcntl.h>
-#include <netdb.h>
-#include <netinet/in.h>
-#include <netinet/tcp.h>
-#include <sys/socket.h>
-#include <sys/types.h>
-
-
-namespace tcp {
-
-
-using HostString = std::array<char, 64>;
-
-//
-//
-// Non blocking server
-//
-//
-
-struct ServerSettings {
-    uint16_t port = 0;
-};
-
-class NonBlockingServer {
-public:
-    NonBlockingServer(ServerSettings settings);
-    ~NonBlockingServer();
-
-    [[nodiscard]] std::expected<void, int> start_listening();
-
-    bool                                   next_client_available();
-    [[nodiscard]] std::expected<void, int> accept_next_client();
-    void                                   disconnect();
-
-    [[nodiscard]] std::expected<int, int>
-    send(std::span<const std::byte> data) const;
-
-    [[nodiscard]] std::expected<int, int>
-    recv(std::span<std::byte> buffer) const;
-
-    bool data_available();
-
-    [[nodiscard]] std::expected<std::array<char, 16>, int>
-    get_client_ip_as_string() const;
-
-private:
-    ServerSettings           m_settings;
-    const struct sockaddr_in m_serverAddress;
-    int                      m_serverSocket = -1;
-
-    pollfd m_serverPfdIn = {.fd = -1, .events = POLLIN};
-    pollfd m_clientPfdIn = {.fd = -1, .events = POLLIN};
-
-    int             m_clientSocket = -1;
-    struct sockaddr m_clientAddress;
-    socklen_t       m_clientAddrLen = sizeof(m_clientAddress);
-
-
-    [[nodiscard]] std::expected<void, int> create_socket();
-    void                                   close_server_socket();
-    void                                   close_client_socket();
-};
-
-
-//
-//
-// Non blocking client
-//
-//
-
-
-class NonBlockingClient {
-public:
-    ~NonBlockingClient();
-
-    // clang-format off
-    [[nodiscard]] std::expected<void, int>
-    connect(HostString host, uint16_t port);
-    // clang-format on
-
-    void disconnect();
-
-    [[nodiscard]] std::expected<int, int> get_last_connection_status();
-
-    bool data_available();
-
-    [[nodiscard]] std::expected<int, int> recv(std::span<std::byte> buffer);
-    [[nodiscard]] std::expected<int, int> send(std::span<const std::byte> data);
-
-private:
-    int    m_socket = -1;
-    pollfd m_pfdOut = {.fd = -1, .events = POLLOUT};
-    pollfd m_pfdIn  = {.fd = -1, .events = POLLIN};
-
-    bool m_startedNewConAttempt = false;
-    int  m_lastKnownConStatus   = ENOTCONN;
-
-    void close_socket();
-
-    [[nodiscard]] std::expected<void, int> create_socket();
-    [[nodiscard]] std::expected<bool, int> new_error_codes_available();
-};
-
-
-} // namespace tcp

src/tcp_client.cpp

@@ -0,0 +1,300 @@
+#include "tcp_client.hpp"
+
+// C stdlib includes
+#include <arpa/inet.h>
+#include <fcntl.h>
+#include <netdb.h>
+
+// Library includes
+#include <spdlog/spdlog.h>
+
+
+namespace tcp {
+
+
+//
+//
+// Blocking client
+//
+//
+
+
+BlockingClient::~BlockingClient() {
+    close_socket();
+}
+
+[[nodiscard]] std::expected<void, int>
+BlockingClient::connect(const HostString& host, uint16_t port) {
+    /// Resolve host
+
+    auto addrRes = detail::resolve_remote_address(host.data(), port);
+    if (!addrRes) return std::unexpected{addrRes.error()};
+    sockaddr_in serverAddress = addrRes.value();
+
+    /// Create socket
+
+    close_socket();
+
+    m_socket = socket(AF_INET, SOCK_STREAM, 0);
+    if (m_socket < 1) {
+        spdlog::error("tcp::BlockingClient: socket() failed with errno={}",
+                      errno);
+        close_socket();
+        return std::unexpected{errno};
+    }
+
+    /// Connect
+
+    int connectRes = ::connect(m_socket, (struct sockaddr*)&serverAddress,
+                               sizeof(serverAddress));
+
+    if (connectRes < 0) {
+        spdlog::error("tcp::BlockingClient: connect() failed with errno={}",
+                      errno);
+        return std::unexpected{errno};
+    }
+
+    return {};
+}
+
+void BlockingClient::disconnect() {
+    close_socket();
+}
+
+[[nodiscard]] std::expected<int, int>
+BlockingClient::send(std::span<const std::byte> data) {
+    const int bytesWritten =
+        ::send(m_socket, (const char*)data.data(), data.size(), 0);
+
+    if (bytesWritten <= 0) {
+        spdlog::error("tcp::BlockingClient: send() failed with errno={}",
+                      errno);
+        return std::unexpected{errno};
+    }
+
+    return bytesWritten;
+}
+
+[[nodiscard]] std::expected<int, int>
+BlockingClient::recv(std::span<std::byte> buffer) {
+    const int bytesReceived =
+        ::recv(m_socket, (char*)buffer.data(), buffer.size(), 0);
+
+    if (bytesReceived < 0) {
+        spdlog::error("tcp::BlockingClient: recv() failed with errno={}",
+                      errno);
+        return std::unexpected{errno};
+    }
+    return {bytesReceived};
+}
+
+void BlockingClient::close_socket() {
+    if (shutdown(m_socket, 0) < 0) {
+        spdlog::debug("tcp::BlockingClient: shutdown() failed with errno={}",
+                      errno);
+    }
+
+    if (close(m_socket) < 0) {
+        spdlog::debug("tcp::BlockingClient: close() failed with errno={}",
+                      errno);
+    }
+
+    m_socket = -1;
+}
+
+
+//
+//
+// Non blocking client
+//
+//
+
+
+NonBlockingClient::~NonBlockingClient() {
+    close_socket();
+}
+
+[[nodiscard]] std::expected<void, int>
+NonBlockingClient::connect(const HostString& host, uint16_t port) {
+    /// Resolve host
+
+    auto addrRes = detail::resolve_remote_address(host.data(), port);
+    if (!addrRes) return std::unexpected{addrRes.error()};
+    sockaddr_in serverAddress = addrRes.value();
+
+    /// Create socket
+
+    close_socket();
+    if (auto res = create_socket(); !res) {
+        return std::unexpected{res.error()};
+    }
+
+    /// Connect
+
+    int connectRes = ::connect(m_socket, (struct sockaddr*)&serverAddress,
+                               sizeof(serverAddress));
+
+    if (connectRes < 0 && errno != EINPROGRESS) {
+        spdlog::error("tcp::NonBlockingClient: connect() failed with errno={}",
+                      errno);
+        return std::unexpected{errno};
+    }
+
+    m_startedNewConAttempt = true;
+
+    return {};
+}
+
+void NonBlockingClient::disconnect() {
+    m_lastKnownConStatus = ENOTCONN;
+    close_socket();
+}
+
+///
+/// @brief Get last known connection status
+/// @return - expected(EINPROGRESS) if connection is still being attempted
+///         - expected(EISCONN) if already connected
+///         - expected(error code) if an error occurred during connection (e.g.,
+///           ECONNREFUSED)
+///         - unexpected(errno) if an error occurred while checking connection
+///           status
+///
+[[nodiscard]] std::expected<int, int>
+NonBlockingClient::get_last_connection_status() {
+    if (!m_startedNewConAttempt) return m_lastKnownConStatus;
+
+    /// Check if connect operation has been completed
+
+    auto pendingOpRes = socket_has_new_output_event();
+    if (!pendingOpRes) return std::unexpected{pendingOpRes.error()};
+    if (!pendingOpRes.value()) return EINPROGRESS;
+
+    m_startedNewConAttempt = false;
+
+    /// Check for connection errors
+
+    int       err = 0;
+    socklen_t len = sizeof(err);
+    if (getsockopt(m_socket, SOL_SOCKET, SO_ERROR, &err, &len) < 0) {
+        spdlog::error(
+            "tcp::NonBlockingClient: getsockopt() failed with errno={}", errno);
+        return std::unexpected{errno};
+    }
+
+    if (err == 0) {
+        m_lastKnownConStatus = EISCONN;
+    } else {
+        m_lastKnownConStatus = err;
+    }
+
+    return m_lastKnownConStatus;
+}
+
+bool NonBlockingClient::data_available() {
+    auto conRes = get_last_connection_status();
+    if (!conRes) return false;
+    if (conRes.value() != EISCONN) return false;
+
+    int ret = poll(&m_pfdIn, 1, 0);
+    if (ret < 0) {
+        spdlog::error("tcp::NonBlockingClient: poll() failed with errno={}",
+                      errno);
+        return false;
+    }
+
+    return (m_pfdIn.revents & POLLIN);
+}
+
+[[nodiscard]] std::expected<int, int>
+NonBlockingClient::send(std::span<const std::byte> data) {
+    const int bytesWritten =
+        ::send(m_socket, (const char*)data.data(), data.size(), 0);
+
+    if (bytesWritten <= 0) {
+        spdlog::error("tcp::NonBlockingClient: send() failed with errno={}",
+                      errno);
+        return std::unexpected{errno};
+    }
+
+    return bytesWritten;
+}
+
+[[nodiscard]] std::expected<int, int>
+NonBlockingClient::recv(std::span<std::byte> buffer) {
+    const int bytesReceived =
+        ::recv(m_socket, (char*)buffer.data(), buffer.size(), 0);
+
+    if (bytesReceived < 0) {
+        spdlog::error("tcp::NonBlockingClient: recv() failed with errno={}",
+                      errno);
+        return std::unexpected{errno};
+    }
+    return {bytesReceived};
+}
+
+[[nodiscard]] std::expected<void, int> NonBlockingClient::create_socket() {
+    m_socket = socket(AF_INET, SOCK_STREAM, 0);
+    if (m_socket < 1) {
+        spdlog::error("tcp::NonBlockingClient: socket() failed with errno={}",
+                      errno);
+        close_socket();
+        return std::unexpected{errno};
+    }
+
+    m_pfdOut.fd = m_socket;
+    m_pfdIn.fd  = m_socket;
+
+    auto currentFlags = fcntl(m_socket, F_GETFL, 0);
+    if (currentFlags == -1) {
+        spdlog::error("tcp::NonBlockingClient: fcntl() failed with errno={}",
+                      errno);
+        close_socket();
+        return std::unexpected{errno};
+    }
+
+    if (fcntl(m_socket, F_SETFL, (currentFlags) | O_NONBLOCK) == -1) {
+        spdlog::error("tcp::NonBlockingClient: fcntl() failed with errno={}",
+                      errno);
+        close_socket();
+        return std::unexpected{errno};
+    }
+
+    return {};
+}
+
+void NonBlockingClient::close_socket() {
+    if (shutdown(m_socket, 0) < 0) {
+        spdlog::debug("tcp::NonBlockingClient: shutdown() failed with errno={}",
+                      errno);
+    }
+
+    if (close(m_socket) < 0) {
+        spdlog::debug("tcp::NonBlockingClient: close() failed with errno={}",
+                      errno);
+    }
+
+    m_socket    = -1;
+    m_pfdOut.fd = -1;
+    m_pfdIn.fd  = -1;
+}
+
+
+///
+/// @return true if there is new output event, i.e., the connect() operation has
+/// completed (successfully or not)
+///
+[[nodiscard]] std::expected<bool, int>
+NonBlockingClient::socket_has_new_output_event() {
+    int ret = poll(&m_pfdOut, 1, 0);
+    if (ret < 0) {
+        spdlog::error("tcp::NonBlockingClient: poll() failed with errno={}",
+                      errno);
+        return std::unexpected{errno};
+    }
+
+    // ret == 0 means the operation timed out, i.e., no new events
+    return (ret != 0);
+}
+
+
+} // namespace tcp

src/tcp_client.hpp

@@ -0,0 +1,95 @@
+#pragma once
+
+
+// STL includes
+#include <cerrno>
+#include <cstdint>
+#include <expected>
+#include <span>
+
+// C stdlib includes
+#include <netinet/in.h>
+#include <sys/poll.h>
+
+// Project includes
+#include "common.hpp"
+
+
+namespace tcp {
+
+
+//
+//
+// Blocking client
+//
+//
+
+
+class BlockingClient {
+public:
+    BlockingClient()                                 = default;
+    BlockingClient(const BlockingClient&)            = delete;
+    BlockingClient(BlockingClient&&)                 = delete;
+    BlockingClient& operator=(const BlockingClient&) = delete;
+    BlockingClient& operator=(BlockingClient&&)      = delete;
+    ~BlockingClient();
+
+    [[nodiscard]] std::expected<void, int> connect(const HostString& host,
+                                                   uint16_t          port);
+
+    void disconnect();
+
+    [[nodiscard]] std::expected<int, int> send(std::span<const std::byte> data);
+    [[nodiscard]] std::expected<int, int> recv(std::span<std::byte> buffer);
+
+private:
+    int m_socket = -1;
+
+    void close_socket();
+};
+
+
+//
+//
+// Non blocking client
+//
+//
+
+
+class NonBlockingClient {
+public:
+    NonBlockingClient()                                    = default;
+    NonBlockingClient(const NonBlockingClient&)            = delete;
+    NonBlockingClient(NonBlockingClient&&)                 = delete;
+    NonBlockingClient& operator=(const NonBlockingClient&) = delete;
+    NonBlockingClient& operator=(NonBlockingClient&&)      = delete;
+    ~NonBlockingClient();
+
+    [[nodiscard]] std::expected<void, int> connect(const HostString& host,
+                                                   uint16_t          port);
+
+    void disconnect();
+
+    [[nodiscard]] std::expected<int, int> get_last_connection_status();
+
+    bool data_available();
+
+    [[nodiscard]] std::expected<int, int> send(std::span<const std::byte> data);
+    [[nodiscard]] std::expected<int, int> recv(std::span<std::byte> buffer);
+
+private:
+    int    m_socket = -1;
+    pollfd m_pfdOut = {.fd = -1, .events = POLLOUT};
+    pollfd m_pfdIn  = {.fd = -1, .events = POLLIN};
+
+    bool m_startedNewConAttempt = false;
+    int  m_lastKnownConStatus   = ENOTCONN;
+
+    [[nodiscard]] std::expected<void, int> create_socket();
+    void                                   close_socket();
+
+    [[nodiscard]] std::expected<bool, int> socket_has_new_output_event();
+};
+
+
+} // namespace tcp

src/tcp_server.cpp

@@ -1,57 +1,184 @@
-#include "tcp.hpp"
+#include "tcp_server.hpp"
 
+// C stdlib includes
 #include <arpa/inet.h>
-#include <cerrno>
-#include <cstdint>
-#include <expected>
 #include <fcntl.h>
 #include <netdb.h>
-#include <netinet/in.h>
+
-#include <netinet/tcp.h>
+// Library includes
-#include <poll.h>
-#include <span>
 #include <spdlog/spdlog.h>
-#include <sys/socket.h>
-#include <sys/types.h>
 
-
+// Project includes
-namespace {
+#include "common.hpp"
-
-
-std::expected<sockaddr_in, int> resolve_remote_address(const char* host,
-                                                       uint16_t    port) {
-    hostent* server = gethostbyname(host);
-    if (server == nullptr) {
-        spdlog::error("tcp: get_host_by_name() failed with h_errno={}",
-                      h_errno);
-        return std::unexpected{h_errno};
-    }
-
-    sockaddr_in address{};
-    address.sin_family = AF_INET;
-    address.sin_port   = htons(port);
-    bcopy((char*)server->h_addr, (char*)&address.sin_addr.s_addr,
-          server->h_length);
-
-    return address;
-}
-
-inline auto get_local_address(uint16_t port) -> sockaddr_in {
-    sockaddr_in address{};
-    address.sin_addr.s_addr = htonl(INADDR_ANY);
-    address.sin_family      = AF_INET;
-    address.sin_port        = htons(port);
-    return address;
-}
-
-
-
-} // namespace
 
 
 namespace tcp {
 
 
+//
+//
+// Blocking server
+//
+//
+
+
+BlockingServer::~BlockingServer() {
+    close_client_socket();
+    close_server_socket();
+}
+
+///
+/// @details Calling this repeatedly closes the previous socket and creates a
+/// new one.
+///
+std::expected<void, int> BlockingServer::start_listening(uint16_t port) {
+    /// Create socket
+
+    close_server_socket();
+    if (auto res = create_server_socket(); !res) {
+        return std::unexpected{res.error()};
+    }
+
+    /// Bind socket and start listening
+
+    const struct sockaddr_in serverAddress = detail::get_local_address(port);
+
+    if (::bind(m_serverSocket, (struct sockaddr*)&serverAddress,
+               sizeof(serverAddress)) != 0) {
+        spdlog::error("tcp::BlockingServer: bind() failed with errno={}",
+                      errno);
+        close_server_socket();
+        return std::unexpected{errno};
+    };
+
+    if (::listen(m_serverSocket, 1) != 0) {
+        spdlog::error("tcp::BlockingServer: listen() failed with errno={}",
+                      errno);
+        close_server_socket();
+        return std::unexpected{errno};
+    }
+
+    return {};
+}
+
+void BlockingServer::stop_listening() {
+    close_server_socket();
+}
+
+[[nodiscard]] std::expected<void, int> BlockingServer::accept() {
+    disconnect_from_client();
+
+    socklen_t clientAddrLen = sizeof(m_clientAddress);
+
+    int result = ::accept(m_serverSocket, (struct sockaddr*)&m_clientAddress,
+                          &clientAddrLen);
+    if (result < 0) return std::unexpected{errno};
+
+    m_clientSocket = result;
+
+    return {};
+}
+
+void BlockingServer::disconnect_from_client() {
+    close_client_socket();
+}
+
+[[nodiscard]] std::expected<std::array<char, 16>, int>
+BlockingServer::get_client_ip_as_string() {
+    std::array<char, 16> addrStr;
+
+    if (inet_ntop(AF_INET, &((struct sockaddr_in*)&m_clientAddress)->sin_addr,
+                  addrStr.data(), addrStr.size()) == nullptr) {
+        spdlog::error("tcp::BlockingServer: inet_ntop() failed with errno={}",
+                      errno);
+        return std::unexpected{errno};
+    }
+
+    // if (inet_ntoa_r(((struct sockaddr_in*)&m_clientAddress)->sin_addr,
+    //               addrStr.data(), addrStr.size()) == nullptr) {
+    //     return std::unexpected{errno};
+    // }
+
+    return addrStr;
+}
+
+[[nodiscard]] std::expected<int, int>
+BlockingServer::send(std::span<const std::byte> data) {
+    const int bytesWritten =
+        ::send(m_clientSocket, (const char*)data.data(), data.size(), 0);
+
+    if (bytesWritten <= 0) {
+        spdlog::error("tcp::BlockingServer: send() failed with errno={}",
+                      errno);
+        return std::unexpected{errno};
+    }
+
+    return bytesWritten;
+}
+
+[[nodiscard]] std::expected<int, int>
+BlockingServer::recv(std::span<std::byte> buffer) {
+    const int bytesReceived =
+        ::recv(m_clientSocket, (char*)buffer.data(), buffer.size(), 0);
+
+    if (bytesReceived < 0) {
+        spdlog::error("tcp::BlockingServer: recv() failed with errno={}",
+                      errno);
+        return std::unexpected{errno};
+    }
+    return {bytesReceived};
+}
+
+[[nodiscard]] std::expected<void, int> BlockingServer::create_server_socket() {
+    m_serverSocket = socket(AF_INET, SOCK_STREAM, 0);
+    if (m_serverSocket < 1) {
+        spdlog::error("tcp::BlockingServer: socket() failed with errno={}",
+                      errno);
+        close_server_socket();
+        return std::unexpected{errno};
+    }
+
+    int flag = 1;
+    if (::setsockopt(m_serverSocket, SOL_SOCKET, SO_REUSEADDR, &flag,
+                     sizeof(flag)) < 0) {
+        spdlog::error("tcp::BlockingServer: setsockopt() failed with errno={}",
+                      errno);
+        close_server_socket();
+        return std::unexpected{errno};
+    }
+
+    return {};
+}
+
+void BlockingServer::close_server_socket() {
+    if (shutdown(m_serverSocket, 0) < 0) {
+        spdlog::debug("tcp::BlockingServer: shutdown() failed with errno={}",
+                      errno);
+    }
+
+    if (close(m_serverSocket) < 0) {
+        spdlog::debug("tcp::BlockingServer: close() failed with errno={}",
+                      errno);
+    }
+
+    m_serverSocket = -1;
+}
+
+void BlockingServer::close_client_socket() {
+    if (shutdown(m_clientSocket, 0) < 0) {
+        spdlog::debug("tcp::BlockingServer: shutdown() failed with errno={}",
+                      errno);
+    }
+
+    if (close(m_clientSocket) < 0) {
+        spdlog::debug("tcp::BlockingServer: close() failed with errno={}",
+                      errno);
+    }
+
+    m_clientSocket = -1;
+}
+
+
 //
 //
 // Non blocking server
@@ -59,43 +186,49 @@ namespace tcp {
 //
 
 
-NonBlockingServer::NonBlockingServer(ServerSettings settings)
-    : m_settings{settings}, m_serverAddress(get_local_address(settings.port)) {
-}
-
 NonBlockingServer::~NonBlockingServer() {
     close_client_socket();
     close_server_socket();
 }
 
-std::expected<void, int> NonBlockingServer::start_listening() {
+///
+/// @details Calling this repeatedly closes the previous socket and creates a
+/// new one.
+///
+std::expected<void, int> NonBlockingServer::start_listening(uint16_t port) {
     /// Create socket
 
     close_server_socket();
-    if (auto res = create_socket(); !res) {
+    if (auto res = create_server_socket(); !res) {
         return std::unexpected{res.error()};
     }
 
-    /// Bin socket and start listening
+    /// Bind socket and start listening
 
-    if (::bind(m_serverSocket, (struct sockaddr*)&m_serverAddress,
+    const struct sockaddr_in serverAddress = detail::get_local_address(port);
-               sizeof(m_serverAddress)) != 0) {
+
+    if (::bind(m_serverSocket, (struct sockaddr*)&serverAddress,
+               sizeof(serverAddress)) != 0) {
         spdlog::error("tcp::NonBlockingServer: bind() failed with errno={}",
                       errno);
-        close(m_serverSocket);
+        close_server_socket();
         return std::unexpected{errno};
     };
 
     if (::listen(m_serverSocket, 1) != 0) {
         spdlog::error("tcp::NonBlockingServer: listen() failed with errno={}",
                       errno);
-        close(m_serverSocket);
+        close_server_socket();
         return std::unexpected{errno};
     }
 
     return {};
 }
 
+void NonBlockingServer::stop_listening() {
+    close_server_socket();
+}
+
 bool NonBlockingServer::next_client_available() {
     int ret = poll(&m_serverPfdIn, 1, 0);
     if (ret < 0) {
@@ -108,10 +241,12 @@ bool NonBlockingServer::next_client_available() {
 }
 
 [[nodiscard]] std::expected<void, int> NonBlockingServer::accept_next_client() {
-    disconnect();
+    disconnect_from_client();
+
+    socklen_t clientAddrLen = sizeof(m_clientAddress);
 
     int result = ::accept(m_serverSocket, (struct sockaddr*)&m_clientAddress,
-                          &m_clientAddrLen);
+                          &clientAddrLen);
     if (result < 0) return std::unexpected{errno};
 
     m_clientSocket   = result;
@@ -119,16 +254,13 @@ bool NonBlockingServer::next_client_available() {
 
     return {};
 }
-void NonBlockingServer::disconnect() {
+
+void NonBlockingServer::disconnect_from_client() {
     close_client_socket();
 }
 
-// TODO: Do we need this?
-// bool NonBlockingServer::socket_closed() const {
-// }
-
 [[nodiscard]] std::expected<std::array<char, 16>, int>
-NonBlockingServer::get_client_ip_as_string() const {
+NonBlockingServer::get_client_ip_as_string() {
     std::array<char, 16> addrStr;
 
     if (inet_ntop(AF_INET, &((struct sockaddr_in*)&m_clientAddress)->sin_addr,
@@ -143,34 +275,7 @@ NonBlockingServer::get_client_ip_as_string() const {
     //     return std::unexpected{errno};
     // }
 
-    return {addrStr};
+    return addrStr;
-}
-
-[[nodiscard]] std::expected<int, int>
-NonBlockingServer::send(std::span<const std::byte> data) const {
-    const int bytesWritten =
-        ::send(m_clientSocket, (const char*)data.data(), data.size(), 0);
-
-    if (bytesWritten <= 0) {
-        spdlog::error("tcp::NonBlockingServer: send() failed with errno={}",
-                      errno);
-        return std::unexpected{errno};
-    }
-
-    return bytesWritten;
-}
-
-[[nodiscard]] std::expected<int, int>
-NonBlockingServer::recv(std::span<std::byte> buffer) const {
-    const int bytesReceived =
-        ::recv(m_clientSocket, (char*)buffer.data(), buffer.size(), 0);
-
-    if (bytesReceived < 0) {
-        spdlog::error("tcp::NonBlockingServer: recv() failed with errno={}",
-                      errno);
-        return std::unexpected{errno};
-    }
-    return {bytesReceived};
 }
 
 bool NonBlockingServer::data_available() {
@@ -184,11 +289,40 @@ bool NonBlockingServer::data_available() {
     return (m_clientPfdIn.revents & POLLIN);
 }
 
-[[nodiscard]] std::expected<void, int> NonBlockingServer::create_socket() {
+[[nodiscard]] std::expected<int, int>
+NonBlockingServer::send(std::span<const std::byte> data) {
+    const int bytesWritten =
+        ::send(m_clientSocket, (const char*)data.data(), data.size(), 0);
+
+    if (bytesWritten <= 0) {
+        spdlog::error("tcp::NonBlockingServer: send() failed with errno={}",
+                      errno);
+        return std::unexpected{errno};
+    }
+
+    return bytesWritten;
+}
+
+[[nodiscard]] std::expected<int, int>
+NonBlockingServer::recv(std::span<std::byte> buffer) {
+    const int bytesReceived =
+        ::recv(m_clientSocket, (char*)buffer.data(), buffer.size(), 0);
+
+    if (bytesReceived < 0) {
+        spdlog::error("tcp::NonBlockingServer: recv() failed with errno={}",
+                      errno);
+        return std::unexpected{errno};
+    }
+    return {bytesReceived};
+}
+
+[[nodiscard]] std::expected<void, int>
+NonBlockingServer::create_server_socket() {
     m_serverSocket = socket(AF_INET, SOCK_STREAM, 0);
     if (m_serverSocket < 1) {
         spdlog::error("tcp::NonBlockingServer: socket() failed with errno={}",
                       errno);
+        close_server_socket();
         return std::unexpected{errno};
     }
 
@@ -252,191 +386,4 @@ void NonBlockingServer::close_client_socket() {
 }
 
 
-//
-//
-// Non blocking client
-//
-//
-
-
-NonBlockingClient::~NonBlockingClient() {
-    close_socket();
-}
-
-[[nodiscard]] std::expected<void, int>
-NonBlockingClient::connect(HostString host, uint16_t port) {
-    /// Resolve host
-
-    auto addrRes = resolve_remote_address(host.data(), port);
-    if (!addrRes) return std::unexpected{addrRes.error()};
-    sockaddr_in serverAddress = addrRes.value();
-
-    /// Create socket
-
-    close_socket();
-    if (auto res = create_socket(); !res) {
-        return std::unexpected{res.error()};
-    }
-
-    /// Connect
-
-    int connectRes = ::connect(m_socket, (struct sockaddr*)&serverAddress,
-                               sizeof(serverAddress));
-
-    if (connectRes < 0 && errno != EINPROGRESS) {
-        spdlog::error("tcp::NonBlockingClient: connect() failed with errno={}",
-                      errno);
-        return std::unexpected{errno};
-    }
-
-    m_startedNewConAttempt = true;
-
-    return {};
-}
-
-[[nodiscard]] std::expected<int, int>
-NonBlockingClient::get_last_connection_status() {
-    if (!m_startedNewConAttempt) return m_lastKnownConStatus;
-
-    /// Check if connect operation has been completed
-
-    auto pendingOpRes = new_error_codes_available();
-    if (!pendingOpRes) return std::unexpected{pendingOpRes.error()};
-    if (!pendingOpRes.value()) return EINPROGRESS;
-
-    m_startedNewConAttempt = false;
-
-    /// Check for connection errors
-
-    int       err = 0;
-    socklen_t len = sizeof(err);
-    if (getsockopt(m_socket, SOL_SOCKET, SO_ERROR, &err, &len) < 0) {
-        spdlog::error(
-            "tcp::NonBlockingClient: getsockopt() failed with errno={}", errno);
-        return std::unexpected{errno};
-    }
-
-    if (err == 0) {
-        m_lastKnownConStatus = EISCONN;
-    } else {
-        m_lastKnownConStatus = err;
-    }
-
-    return m_lastKnownConStatus;
-}
-
-void NonBlockingClient::disconnect() {
-    m_lastKnownConStatus = ENOTCONN;
-    close_socket();
-}
-
-[[nodiscard]] std::expected<int, int>
-NonBlockingClient::send(std::span<const std::byte> data) {
-    // TODO: Do we need this?
-    auto conRes = get_last_connection_status();
-    if (!conRes) return std::unexpected{conRes.error()};
-    if (conRes.value() != EISCONN) {
-        spdlog::error("tcp::NonBlockingClient: Socket not connected");
-        return std::unexpected{ENOTCONN};
-    }
-
-    const int bytesWritten =
-        ::send(m_socket, (const char*)data.data(), data.size(), 0);
-
-    if (bytesWritten <= 0) {
-        spdlog::error("tcp::NonBlockingClient: send() failed with errno={}",
-                      errno);
-        return std::unexpected{errno};
-    }
-
-    return bytesWritten;
-}
-
-bool NonBlockingClient::data_available() {
-    auto conRes = get_last_connection_status();
-    if (!conRes) return false;
-    if (conRes.value() != EISCONN) return false;
-
-    int ret = poll(&m_pfdIn, 1, 0);
-    if (ret < 0) {
-        spdlog::error("tcp::NonBlockingClient: poll() failed with errno={}",
-                      errno);
-        return false;
-    }
-
-    return (m_pfdIn.revents & POLLIN);
-}
-
-[[nodiscard]] std::expected<int, int>
-NonBlockingClient::recv(std::span<std::byte> buffer) {
-    const int bytesReceived =
-        ::recv(m_socket, (char*)buffer.data(), buffer.size(), 0);
-
-    if (bytesReceived < 0) {
-        spdlog::error("tcp::NonBlockingClient: recv() failed with errno={}",
-                      errno);
-        return std::unexpected{errno};
-    }
-    return {bytesReceived};
-}
-
-void NonBlockingClient::close_socket() {
-    if (shutdown(m_socket, 0) < 0) {
-        spdlog::debug("tcp::NonBlockingClient: shutdown() failed with errno={}",
-                      errno);
-    }
-
-    if (close(m_socket) < 0) {
-        spdlog::debug("tcp::NonBlockingClient: close() failed with errno={}",
-                      errno);
-    }
-
-    m_socket    = -1;
-    m_pfdOut.fd = -1;
-    m_pfdIn.fd  = -1;
-}
-
-[[nodiscard]] std::expected<void, int> NonBlockingClient::create_socket() {
-    m_socket = socket(AF_INET, SOCK_STREAM, 0);
-    if (m_socket < 1) {
-        spdlog::error("tcp::NonBlockingClient: socket() failed with errno={}",
-                      errno);
-        return std::unexpected{errno};
-    }
-
-    m_pfdOut.fd = m_socket;
-    m_pfdIn.fd  = m_socket;
-
-    auto currentFlags = fcntl(m_socket, F_GETFL, 0);
-    if (currentFlags == -1) {
-        spdlog::error("tcp::NonBlockingClient: fcntl() failed with errno={}",
-                      errno);
-        close_socket();
-        return std::unexpected{errno};
-    }
-
-    if (fcntl(m_socket, F_SETFL, (currentFlags) | O_NONBLOCK) == -1) {
-        spdlog::error("tcp::NonBlockingClient: fcntl() failed with errno={}",
-                      errno);
-        close_socket();
-        return std::unexpected{errno};
-    }
-
-    return {};
-}
-
-[[nodiscard]] std::expected<bool, int>
-NonBlockingClient::new_error_codes_available() {
-    int ret = poll(&m_pfdOut, 1, 0);
-    if (ret < 0) {
-        spdlog::error("tcp::NonBlockingClient: poll() failed with errno={}",
-                      errno);
-        return std::unexpected{errno};
-    }
-
-    // ret == 0 means the operation timed out, i.e., no new events
-    return (ret != 0);
-}
-
-
 } // namespace tcp

src/tcp_server.hpp

@@ -0,0 +1,104 @@
+#pragma once
+
+
+// STL includes
+#include <cerrno>
+#include <cstdint>
+#include <expected>
+#include <span>
+
+// C stdlib includes
+#include <netinet/in.h>
+#include <sys/poll.h>
+
+
+namespace tcp {
+
+
+//
+//
+// Blocking server
+//
+//
+
+
+class BlockingServer {
+public:
+    BlockingServer()                                 = default;
+    BlockingServer(const BlockingServer&)            = delete;
+    BlockingServer(BlockingServer&&)                 = delete;
+    BlockingServer& operator=(const BlockingServer&) = delete;
+    BlockingServer& operator=(BlockingServer&&)      = delete;
+    ~BlockingServer();
+
+    [[nodiscard]] std::expected<void, int> start_listening(uint16_t port);
+    void                                   stop_listening();
+
+    [[nodiscard]] std::expected<void, int> accept();
+    void                                   disconnect_from_client();
+
+    [[nodiscard]] std::expected<std::array<char, 16>, int>
+    get_client_ip_as_string();
+
+    [[nodiscard]] std::expected<int, int> send(std::span<const std::byte> data);
+    [[nodiscard]] std::expected<int, int> recv(std::span<std::byte> buffer);
+
+private:
+    int m_serverSocket = -1;
+
+    int             m_clientSocket  = -1;
+    struct sockaddr m_clientAddress = {0};
+
+    [[nodiscard]] std::expected<void, int> create_server_socket();
+    void                                   close_server_socket();
+    void                                   close_client_socket();
+};
+
+
+//
+//
+// Non blocking server
+//
+//
+
+
+class NonBlockingServer {
+public:
+    NonBlockingServer()                                    = default;
+    NonBlockingServer(const NonBlockingServer&)            = delete;
+    NonBlockingServer(NonBlockingServer&&)                 = delete;
+    NonBlockingServer& operator=(const NonBlockingServer&) = delete;
+    NonBlockingServer& operator=(NonBlockingServer&&)      = delete;
+    ~NonBlockingServer();
+
+    [[nodiscard]] std::expected<void, int> start_listening(uint16_t port);
+    void                                   stop_listening();
+
+    bool                                   next_client_available();
+    [[nodiscard]] std::expected<void, int> accept_next_client();
+    void                                   disconnect_from_client();
+
+    [[nodiscard]] std::expected<std::array<char, 16>, int>
+    get_client_ip_as_string();
+
+    bool data_available();
+
+    [[nodiscard]] std::expected<int, int> send(std::span<const std::byte> data);
+    [[nodiscard]] std::expected<int, int> recv(std::span<std::byte> buffer);
+
+private:
+    int m_serverSocket = -1;
+
+    pollfd m_serverPfdIn = {.fd = -1, .events = POLLIN};
+    pollfd m_clientPfdIn = {.fd = -1, .events = POLLIN};
+
+    int             m_clientSocket  = -1;
+    struct sockaddr m_clientAddress = {0};
+
+    [[nodiscard]] std::expected<void, int> create_server_socket();
+    void                                   close_server_socket();
+    void                                   close_client_socket();
+};
+
+
+} // namespace tcp

tests/tcp_blocking.cpp

@@ -0,0 +1,202 @@
+#include <gtest/gtest.h>
+
+// STL includes
+#include <cstring>
+#include <thread>
+
+// Project includes
+#include "tcp_client.hpp"
+#include "tcp_server.hpp"
+
+
+TEST(BlockingTcpServer, Accept) {
+    tcp::BlockingServer server;
+    tcp::BlockingClient client;
+
+    auto lisRes = server.start_listening(1234);
+
+    std::thread clientThread([&client]() {
+        auto conRes = client.connect({"localhost"}, 1234);
+        EXPECT_TRUE(conRes.has_value());
+    });
+
+    std::thread serverThread([&server]() {
+        auto accRes = server.accept();
+        EXPECT_TRUE(accRes.has_value());
+    });
+
+    serverThread.join();
+    clientThread.join();
+}
+
+TEST(BlockingTcpServer, RestartListening) {
+    tcp::BlockingServer server;
+    tcp::BlockingClient client;
+
+    auto lisRes = server.start_listening(1234);
+
+    std::thread clientThread([&client]() {
+        auto conRes = client.connect({"localhost"}, 1234);
+        EXPECT_TRUE(conRes.has_value());
+    });
+
+    clientThread.join();
+
+    auto lisRes2 = server.start_listening(2345);
+
+    std::thread clientThread2([&client]() {
+        auto conRes = client.connect({"localhost"}, 1234);
+        EXPECT_FALSE(conRes.has_value());
+    });
+
+    clientThread2.join();
+
+    std::thread clientThread3([&client]() {
+        auto conRes2 = client.connect({"localhost"}, 2345);
+        EXPECT_TRUE(conRes2.has_value());
+    });
+
+    clientThread3.join();
+}
+
+TEST(BlockingTcpServer, StopListening) {
+    tcp::BlockingServer server;
+    tcp::BlockingClient client;
+
+    auto lisRes = server.start_listening(1234);
+
+    std::thread clientThread([&client]() {
+        auto conRes = client.connect({"localhost"}, 1234);
+        EXPECT_TRUE(conRes.has_value());
+    });
+
+    clientThread.join();
+
+    server.stop_listening();
+
+    std::thread clientThread2([&client]() {
+        auto conRes2 = client.connect({"localhost"}, 1234);
+        EXPECT_FALSE(conRes2.has_value());
+    });
+
+    clientThread2.join();
+}
+
+TEST(BlockingTcpServer, MultipleAccept) {
+    tcp::BlockingServer server;
+    tcp::BlockingClient client1;
+    tcp::BlockingClient client2;
+
+    auto lisRes1 = server.start_listening(1234);
+
+    std::thread clientThread1([&client1]() {
+        auto conRes1 = client1.connect({"localhost"}, 1234);
+        EXPECT_TRUE(conRes1.has_value());
+    });
+
+    std::thread clientThread2([&client2]() {
+        auto conRes2 = client2.connect({"localhost"}, 1234);
+        EXPECT_TRUE(conRes2.has_value());
+    });
+
+    std::thread serverThread([&server]() {
+        auto accRes1 = server.accept();
+        EXPECT_TRUE(accRes1.has_value());
+
+        auto accRes2 = server.accept();
+        EXPECT_TRUE(accRes2.has_value());
+    });
+
+    clientThread1.join();
+    clientThread2.join();
+    serverThread.join();
+}
+
+TEST(BlockingTcpServer, GetClientIPAsString) {
+    tcp::BlockingServer server;
+    tcp::BlockingClient client;
+
+    auto lisRes = server.start_listening(1234);
+    auto conRes = client.connect({"localhost"}, 1234);
+    auto accRes = server.accept();
+
+    auto ipRes = server.get_client_ip_as_string();
+    if (!ipRes) return;
+
+    EXPECT_STREQ(ipRes.value().data(), "127.0.0.1");
+}
+
+TEST(BlockingTcpClient, Connect) {
+    tcp::BlockingServer server;
+    tcp::BlockingClient client;
+
+    auto lisRes = server.start_listening(1234);
+
+    std::thread clientThread([&client]() {
+        auto conRes = client.connect({"localhost"}, 1234);
+        EXPECT_TRUE(conRes.has_value());
+    });
+
+    clientThread.join();
+}
+
+TEST(BlockingClient, Reconnect) {
+    tcp::BlockingServer server1;
+    tcp::BlockingServer server2;
+    tcp::BlockingClient client;
+
+    auto lisRes1 = server1.start_listening(1234);
+    auto lisRes2 = server2.start_listening(2345);
+
+    std::thread clientThread([&client]() {
+        auto conRes = client.connect({"localhost"}, 1234);
+        EXPECT_TRUE(conRes.has_value());
+    });
+
+    clientThread.join();
+
+    std::thread clientThread2([&client]() {
+        auto conRes2 = client.connect({"localhost"}, 2345);
+        EXPECT_TRUE(conRes2.has_value());
+    });
+
+    clientThread2.join();
+}
+
+TEST(BlockingTcpClientServer, ClientSendServerReceive) {
+    tcp::BlockingServer server;
+    tcp::BlockingClient client;
+
+    auto lisRes = server.start_listening(1234);
+    auto conRes = client.connect({"localhost"}, 1234);
+    auto accRes = server.accept();
+
+    std::array<char, 14> txMsg   = {"Hello, World!"};
+    auto                 sendRes = client.send(std::as_bytes(std::span(txMsg)));
+
+    EXPECT_EQ(sendRes.value(), txMsg.size());
+
+    std::array<char, 1024> rxBuffer;
+    auto recvRes = server.recv(std::as_writable_bytes(std::span(rxBuffer)));
+    EXPECT_EQ(recvRes.value(), txMsg.size());
+    EXPECT_EQ(std::strcmp(txMsg.data(), rxBuffer.data()), 0);
+}
+
+TEST(BlockingTcpClientServer, ClientReceiveServerSend) {
+    tcp::BlockingServer server;
+    tcp::BlockingClient client;
+
+    auto lisRes = server.start_listening(1234);
+    auto conRes = client.connect({"localhost"}, 1234);
+    auto accRes = server.accept();
+
+    std::array<char, 14> txMsg   = {"Hello, World!"};
+    auto                 sendRes = server.send(std::as_bytes(std::span(txMsg)));
+
+    EXPECT_EQ(sendRes.value(), txMsg.size());
+
+    std::array<char, 1024> rxBuffer;
+    auto recvRes = client.recv(std::as_writable_bytes(std::span(rxBuffer)));
+    EXPECT_EQ(recvRes.value(), txMsg.size());
+    EXPECT_EQ(std::strcmp(txMsg.data(), rxBuffer.data()), 0);
+}

tests/tcp_non_blocking.cpp

@@ -1,13 +1,18 @@
-#include "tcp.hpp"
-
 #include <gtest/gtest.h>
 
+// STL includes
+#include <cstring>
 
-TEST(TcpServer, Accept) {
+// Project includes
-    tcp::NonBlockingServer server{{.port = 1234}};
+#include "tcp_client.hpp"
+#include "tcp_server.hpp"
+
+
+TEST(NonBlockingTcpServer, Accept) {
+    tcp::NonBlockingServer server;
     tcp::NonBlockingClient client;
 
-    auto lisRes = server.start_listening();
+    auto lisRes = server.start_listening(1234);
 
     EXPECT_FALSE(server.next_client_available());
 
@@ -20,8 +25,86 @@ TEST(TcpServer, Accept) {
     EXPECT_FALSE(server.next_client_available());
 }
 
-TEST(TcpClient, Connect) {
+TEST(NonBlockingTcpServer, RestartListening) {
-    tcp::NonBlockingServer server{{.port = 1234}};
+    tcp::NonBlockingServer server;
+    tcp::NonBlockingClient client;
+
+    auto lisRes = server.start_listening(1234);
+
+    auto conRes = client.connect({"localhost"}, 1234);
+
+    EXPECT_TRUE(server.next_client_available());
+
+    auto lisRes2 = server.start_listening(2345);
+
+    EXPECT_FALSE(server.next_client_available());
+
+    auto conRes2 = client.connect({"localhost"}, 2345);
+
+    EXPECT_TRUE(server.next_client_available());
+
+    auto statRes2 = client.get_last_connection_status();
+    if (!statRes2) return;
+    EXPECT_EQ(statRes2.value(), EISCONN);
+}
+
+TEST(NonBlockingTcpServer, StopListening) {
+    tcp::NonBlockingServer server;
+    tcp::NonBlockingClient client;
+
+    auto lisRes = server.start_listening(1234);
+
+    auto conRes = client.connect({"localhost"}, 1234);
+
+    EXPECT_TRUE(server.next_client_available());
+
+    server.stop_listening();
+
+    EXPECT_FALSE(server.next_client_available());
+
+    auto conRes2 = client.connect({"localhost"}, 1234);
+
+    EXPECT_EQ(client.get_last_connection_status().value(), ECONNREFUSED);
+}
+
+TEST(NonBlockingTcpServer, DataAvailable) {
+    tcp::NonBlockingServer server;
+    tcp::NonBlockingClient client;
+
+    EXPECT_FALSE(server.data_available());
+
+    auto lisRes = server.start_listening(1234);
+    auto conRes = client.connect({"localhost"}, 1234);
+    auto accRes = server.accept_next_client();
+
+    EXPECT_FALSE(server.data_available());
+
+    std::array<char, 14> txMsg   = {"Hello, World!"};
+    auto                 sendRes = client.send(std::as_bytes(std::span(txMsg)));
+    EXPECT_EQ(sendRes.value(), txMsg.size());
+    EXPECT_TRUE(server.data_available());
+
+    std::array<char, 1024> rxBuffer;
+    auto recvRes = server.recv(std::as_writable_bytes(std::span(rxBuffer)));
+    EXPECT_EQ(recvRes.value(), txMsg.size());
+    EXPECT_FALSE(server.data_available());
+}
+
+TEST(NonBlockingTcpServer, GetClientIPAsString) {
+    tcp::NonBlockingServer server;
+    tcp::NonBlockingClient client;
+
+    auto lisRes = server.start_listening(1234);
+    auto conRes = client.connect({"localhost"}, 1234);
+    auto accRes = server.accept_next_client();
+    auto ipRes  = server.get_client_ip_as_string();
+    if (!ipRes) return;
+
+    EXPECT_STREQ(ipRes.value().data(), "127.0.0.1");
+}
+
+TEST(NonBlockingTcpClient, Connect) {
+    tcp::NonBlockingServer server;
     tcp::NonBlockingClient client;
 
     /// Default connection status, i.e., before attempting connection
@@ -40,7 +123,7 @@ TEST(TcpClient, Connect) {
 
     /// Connection status when connection is acknowledged
 
-    auto lisRes = server.start_listening();
+    auto lisRes = server.start_listening(1234);
 
     auto conRes2 = client.connect({"localhost"}, 1234);
 
@@ -57,13 +140,13 @@ TEST(TcpClient, Connect) {
     EXPECT_EQ(statRes4.value(), ECONNREFUSED);
 }
 
-TEST(TcpClient, Reconnect) {
+TEST(NonBlockingTcpClient, Reconnect) {
-    tcp::NonBlockingServer server1{{.port = 1234}};
+    tcp::NonBlockingServer server1;
-    tcp::NonBlockingServer server2{{.port = 2345}};
+    tcp::NonBlockingServer server2;
     tcp::NonBlockingClient client;
 
-    auto lisRes1 = server1.start_listening();
+    auto lisRes1 = server1.start_listening(1234);
-    auto lisRes2 = server2.start_listening();
+    auto lisRes2 = server2.start_listening(2345);
 
     auto conRes1 = client.connect({"localhost"}, 1234);
 
@@ -78,13 +161,13 @@ TEST(TcpClient, Reconnect) {
     EXPECT_EQ(statRes2.value(), EISCONN);
 }
 
-TEST(TcpClient, DataAvailable) {
+TEST(NonBlockingTcpClient, DataAvailable) {
-    tcp::NonBlockingServer server{{.port = 1234}};
+    tcp::NonBlockingServer server;
     tcp::NonBlockingClient client;
 
     EXPECT_FALSE(client.data_available());
 
-    auto lisRes = server.start_listening();
+    auto lisRes = server.start_listening(1234);
     auto conRes = client.connect({"localhost"}, 1234);
     auto accRes = server.accept_next_client();
 
@@ -104,34 +187,11 @@ TEST(TcpClient, DataAvailable) {
     EXPECT_FALSE(client.data_available());
 }
 
-TEST(TcpServer, DataAvailable) {
+TEST(NonBlockingTcpClientServer, ClientSendServerReceive) {
-    tcp::NonBlockingServer server{{.port = 1234}};
+    tcp::NonBlockingServer server;
     tcp::NonBlockingClient client;
 
-    EXPECT_FALSE(server.data_available());
+    auto lisRes = server.start_listening(1234);
-
-    auto lisRes = server.start_listening();
-    auto conRes = client.connect({"localhost"}, 1234);
-    auto accRes = server.accept_next_client();
-
-    EXPECT_FALSE(server.data_available());
-
-    std::array<char, 14> txMsg   = {"Hello, World!"};
-    auto                 sendRes = client.send(std::as_bytes(std::span(txMsg)));
-    EXPECT_EQ(sendRes.value(), txMsg.size());
-    EXPECT_TRUE(server.data_available());
-
-    std::array<char, 1024> rxBuffer;
-    auto recvRes = server.recv(std::as_writable_bytes(std::span(rxBuffer)));
-    EXPECT_EQ(recvRes.value(), txMsg.size());
-    EXPECT_FALSE(server.data_available());
-}
-
-TEST(TcpClientServer, ClientSendServerReceive) {
-    tcp::NonBlockingServer server{{.port = 1234}};
-    tcp::NonBlockingClient client;
-
-    auto lisRes = server.start_listening();
     auto conRes = client.connect({"localhost"}, 1234);
     auto accRes = server.accept_next_client();
 
@@ -147,11 +207,11 @@ TEST(TcpClientServer, ClientSendServerReceive) {
     EXPECT_EQ(std::strcmp(txMsg.data(), rxBuffer.data()), 0);
 }
 
-TEST(TcpClientServer, ClientReceiveServerSend) {
+TEST(NonBlockingTcpClientServer, ClientReceiveServerSend) {
-    tcp::NonBlockingServer server{{.port = 1234}};
+    tcp::NonBlockingServer server;
     tcp::NonBlockingClient client;
 
-    auto lisRes = server.start_listening();
+    auto lisRes = server.start_listening(1234);
     auto conRes = client.connect({"localhost"}, 1234);
     auto accRes = server.accept_next_client();