[5094] Improved and documented TCPAcceptor tests.

src/lib/asiolink/io_socket.h

@@ -1,4 +1,4 @@
-// Copyright (C) 2010-2015 Internet Systems Consortium, Inc. ("ISC")
+// Copyright (C) 2010-2017 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
@@ -35,6 +35,16 @@ namespace asiolink {
 /// derived class for testing purposes rather than providing factory methods
 /// (i.e., getDummy variants below).
 class IOSocket {
+public:
+
+    /// @name Types of objects encapsulating socket options.
+    //@{
+
+    /// @brief Represents SO_REUSEADDR socket option.
+    typedef boost::asio::socket_base::reuse_address ReuseAddress;
+
+    //@}
+
     ///
     /// \name Constructors and Destructor
     ///

src/lib/asiolink/tcp_acceptor.h

@@ -1,4 +1,4 @@
-// Copyright (C) 2016 Internet Systems Consortium, Inc. ("ISC")
+// Copyright (C) 2016-2017 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
@@ -12,48 +12,63 @@
 #endif
 
 #include <asiolink/io_service.h>
+#include <asiolink/io_socket.h>
 #include <asiolink/tcp_endpoint.h>
 #include <asiolink/tcp_socket.h>
+#include <boost/shared_ptr.hpp>
+#include <netinet/in.h>
 
 namespace isc {
 namespace asiolink {
 
 template<typename C>
-class TCPAcceptor {
+class TCPAcceptor : public IOSocket{
 public:
 
     TCPAcceptor(IOService& io_service)
-        : acceptor_(io_service.get_io_service()) {
+        : IOSocket(),
+          acceptor_(new boost::asio::ip::tcp::acceptor(io_service.get_io_service())) {
     }
 
-    void open(const TCPEndpoint& endpoint) {
-        acceptor_.open(endpoint.getASIOEndpoint().protocol());
-        acceptor_.set_option(boost::asio::ip::tcp::acceptor::reuse_address(true));
+    virtual ~TCPAcceptor() { }
+
+    virtual int getNative() const {
+        return (acceptor_->native());
+    }
 
+    virtual int getProtocol() const {
+        return (IPPROTO_TCP);
     }
 
-//    void setOption(const SettableSocketOption& socket_option);
+    void open(const TCPEndpoint& endpoint) {
+        acceptor_->open(endpoint.getASIOEndpoint().protocol());
+    }
+
+    template<typename SettableSocketOption>
+    void setOption(const SettableSocketOption& socket_option) {
+        acceptor_->set_option(socket_option);
+    }
 
     void bind(const TCPEndpoint& endpoint) {
-        acceptor_.bind(endpoint.getASIOEndpoint());
+        acceptor_->bind(endpoint.getASIOEndpoint());
     }
 
     void listen() {
-        acceptor_.listen();
+        acceptor_->listen();
     }
 
     template<typename SocketCallback>
     void asyncAccept(const TCPSocket<SocketCallback>& socket, C& callback) {
-        acceptor_.async_accept(socket.getASIOSocket(), callback);
+        acceptor_->async_accept(socket.getASIOSocket(), callback);
     }
 
     bool isOpen() const {
-        return (acceptor_.is_open());
+        return (acceptor_->is_open());
     }
 
 private:
 
-    boost::asio::ip::tcp::acceptor acceptor_;
+    boost::shared_ptr<boost::asio::ip::tcp::acceptor> acceptor_;
 
 };
 

src/lib/asiolink/tests/tcp_acceptor_unittest.cc

@@ -1,4 +1,4 @@
-// Copyright (C) 2016 Internet Systems Consortium, Inc. ("ISC")
+// Copyright (C) 2016-2017 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
@@ -17,112 +17,222 @@
 #include <boost/shared_ptr.hpp>
 #include <gtest/gtest.h>
 #include <list>
+#include <netinet/in.h>
 #include <string>
 
-using namespace boost::asio::ip;
 using namespace isc::asiolink;
 
 namespace {
 
-class TCPClient;
+/// @brief Local server address used for testing.
+const char SERVER_ADDRESS[] = "127.0.0.1";
 
+/// @brief Local server port used for testing.
+const unsigned short SERVER_PORT = 18123;
+
+/// @brief Test timeout in ms.
+const long TEST_TIMEOUT = 10000;
+
+/// @brief Simple class representing TCP socket callback.
 class SocketCallback {
 public:
 
-    void operator()(boost::system::error_code ec = boost::system::error_code(),
-                            size_t length = 0) {
-        std::cout << "socket callback invoked" << std::endl;
+    /// @brief Implements callback for the asynchornous operation on the socket.
+    ///
+    /// This callback merely checks if error has occurred and reports this
+    /// error. It does nothing in case of success.
+    ///
+    /// @param ec Error code.
+    /// @param length Length of received data.
+    void operator()(boost::system::error_code ec, size_t length = 0) {
+        if (ec) {
+            ADD_FAILURE() << "error occurred for a socket: " << ec.message();
+        }
     }
 
 };
 
-typedef boost::shared_ptr<TCPClient> TCPClientPtr;
-
+/// @brief Entity which can connect to the TCP server endpoint and close the
+/// connection.
 class TCPClient : public boost::noncopyable {
 public:
 
-    TCPClient(IOService& io_service)
+    /// @brief Constructor.
+    ///
+    /// This constructor creates new socket instance. It doesn't connect. Call
+    /// connect() to connect to the server.
+    ///
+    /// @param io_service IO service to be stopped on error.
+    explicit TCPClient(IOService& io_service)
         : io_service_(io_service.get_io_service()), socket_(io_service_) {
     }
 
+    /// @brief Destructor.
+    ///
+    /// Closes the underlying socket if it is open.
+    ~TCPClient() {
+        close();
+    }
+
+    /// @brief Connect to the test server address and port.
+    ///
+    /// This method asynchronously connects to the server endpoint and uses the
+    /// connectHandler as a callback function.
     void connect() {
-        tcp::endpoint endpoint(address::from_string("127.0.0.1"), 18123);
-        try {
-            socket_.connect(endpoint);
-        } catch (const boost::system::system_error& ex) {
-            ADD_FAILURE() << "an error occured while connecting over TCP socket: "
-                          << ex.what();
+        boost::asio::ip::tcp::endpoint
+            endpoint(boost::asio::ip::address::from_string(SERVER_ADDRESS),
+                     SERVER_PORT);
+        socket_.async_connect(endpoint,
+                              boost::bind(&TCPClient::connectHandler, this,_1));
+    }
 
+    /// @brief Callback function for connect().
+    ///
+    /// This function stops the IO service upon error.
+    ///
+    /// @param ec Error code.
+    void connectHandler(const boost::system::error_code& ec) {
+        if (ec) {
+            ADD_FAILURE() << "error occurred while connecting: "
+                          << ec.message();
             io_service_.stop();
         }
     }
 
+    /// @brief Close connection.
     void close() {
         socket_.close();
     }
 
 private:
 
+    /// @brief Holds reference to the IO service.
     boost::asio::io_service& io_service_;
+
+    /// @brief A socket used for the connecion.
     boost::asio::ip::tcp::socket socket_;
 
 };
 
+/// @brief Pointer to the TCPClient.
+typedef boost::shared_ptr<TCPClient> TCPClientPtr;
 
+/// @brief A signature of the function implementing callback for the
+/// TCPAcceptor.
 typedef boost::function<void(const boost::system::error_code&)> TCPAcceptorCallback;
 
+/// @brief TCPAcceptor using TCPAcceptorCallback.
+typedef TCPAcceptor<TCPAcceptorCallback> TestTCPAcceptor;
+
+/// @brief Implements asynchronous TCP acceptor service.
+///
+/// It creates a new socket into which connection is accepted. The socket
+/// is retained until class instance exists.
 class Acceptor {
 public:
 
-    Acceptor(IOService& io_service, TCPAcceptor<TCPAcceptorCallback>& acceptor,
+    /// @brief Constructor.
+    ///
+    /// @param io_service IO service.
+    /// @param acceptor Reference to the TCP acceptor on which asyncAccept
+    /// will be called.
+    /// @param callback Callback function for the asyncAccept.
+    explicit Acceptor(IOService& io_service, TestTCPAcceptor& acceptor,
              const TCPAcceptorCallback& callback)
         : socket_(io_service), acceptor_(acceptor), callback_(callback) {
     }
 
+    /// @brief Destructor.
+    ///
+    /// Closes socket.
+    ~Acceptor() {
+        socket_.close();
+    }
+
+    /// @brief Asynchronous accept new connection.
     void accept() {
         acceptor_.asyncAccept(socket_, callback_);
     }
 
+    /// @brief Close connection.
     void close() {
         socket_.close();
     }
 
 private:
 
+    /// @brief Socket into which connection is accepted.
     TCPSocket<SocketCallback> socket_;
-    TCPAcceptor<TCPAcceptorCallback>& acceptor_;
+
+    /// @brief Reference to the TCPAcceptor on which asyncAccept is called.
+    TestTCPAcceptor& acceptor_;
+
+    /// @brief Instance of the callback used for asyncAccept.
     TCPAcceptorCallback callback_;
 
 };
 
+/// @brief Pointer to the Acceptor object.
 typedef boost::shared_ptr<Acceptor> AcceptorPtr;
 
+/// @brief Test fixture class for TCPAcceptor.
+///
+/// This class provides means for creating new TCP connections, i.e. simulates
+/// clients connecting to the servers via TCPAcceptor. It is possible to create
+/// multiple simultaneous connections, which are retained by the test fixture
+/// class and closed cleanly when the test fixture is destroyed.
 class TCPAcceptorTest : public ::testing::Test {
 public:
 
+    /// @brief Constructor.
+    ///
+    /// Besides initializing class members it also sets the test timer to guard
+    /// against endlessly running IO service when TCP connections are
+    /// unsuccessful.
     TCPAcceptorTest()
-        : io_service_(), acceptor_(io_service_), test_timer_(io_service_),
-          connections_(), clients_(), connections_num_(0), max_connections_(1) {
+        : io_service_(), acceptor_(io_service_),
+          asio_endpoint_(boost::asio::ip::address::from_string(SERVER_ADDRESS),
+                         SERVER_PORT),
+          endpoint_(asio_endpoint_), test_timer_(io_service_), connections_(),
+          clients_(), connections_num_(0), max_connections_(1) {
         test_timer_.setup(boost::bind(&TCPAcceptorTest::timeoutHandler, this),
-                                      10000, IntervalTimer::ONE_SHOT);
+                                      TEST_TIMEOUT, IntervalTimer::ONE_SHOT);
     }
 
+    /// @brief Destructor.
     virtual ~TCPAcceptorTest() {
-        for (auto client = clients_.begin(); client != clients_.end();
-             ++client) {
-            (*client)->close();
-        }
-
-        for (auto conn = connections_.begin(); conn != connections_.end();
-             ++conn) {
-            (*conn)->close();
-        }
     }
 
+    /// @brief Specifies how many new connections are expected before the IO
+    /// service is stopped.
+    ///
+    /// @param max_connections Connections limit.
     void setMaxConnections(const unsigned int max_connections) {
         max_connections_ = max_connections;
     }
 
+    /// @brief Create ASIO endpoint from the provided endpoint by retaining the
+    /// IP address and modifying the port.
+    ///
+    /// This convenience method is useful to create new endpoint from the
+    /// existing endpoint to test reusing IP address for multiple acceptors.
+    /// The returned endpoint has the same IP address but different port.
+    ///
+    /// @param endpoint Source endpoint.
+    ///
+    /// @return New endpoint with the port number increased by 1.
+    boost::asio::ip::tcp::endpoint
+    createSiblingEndpoint(const boost::asio::ip::tcp::endpoint& endpoint) const {
+        boost::asio::ip::tcp::endpoint endpoint_copy(endpoint);
+        endpoint_copy.port(endpoint.port() + 1);
+        return (endpoint_copy);
+    }
+
+    /// @brief Starts accepting TCP connections.
+    ///
+    /// This method creates new Acceptor instance and calls accept() to start
+    /// accepting new connections. The instance of the Acceptor object is
+    /// retained in the connections_ list.
     void accept() {
         TCPAcceptorCallback cb = boost::bind(&TCPAcceptorTest::acceptHandler,
                                              this, _1);
@@ -131,18 +241,31 @@ public:
         connections_.back()->accept();
     }
 
+    /// @brief Connect to the endpoint.
+    ///
+    /// This method creates TCPClient instance and retains it in the clients_
+    /// list.
     void connect() {
         TCPClientPtr client(new TCPClient(io_service_));
         clients_.push_back(client);
         clients_.back()->connect();
     }
 
+    /// @brief Callback function for asynchronous accept calls.
+    ///
+    /// It stops the IO service upon error or when the number of accepted
+    /// connections reaches the max_connections_ value. Otherwise it calls
+    /// accept() to start accepting next connections.
+    ///
+    /// @param ec Error code.
     void acceptHandler(const boost::system::error_code& ec) {
         if (ec) {
             ADD_FAILURE() << "error occurred while accepting connection: "
                           << ec.message();
+            io_service_.stop();
         }
 
+        // We have reached the maximum number of connections - end the test.
         if (++connections_num_ >= max_connections_) {
             io_service_.stop();
 
@@ -151,34 +274,113 @@ public:
         }
     }
 
+    /// @brief Callback function invoke upon test timeout.
+    ///
+    /// It stops the IO service and reports test timeout.
     void timeoutHandler() {
         ADD_FAILURE() << "Timeout occurred while running the test!";
         io_service_.stop();
     }
 
+    /// @brief IO service.
     IOService io_service_;
-    TCPAcceptor<TCPAcceptorCallback> acceptor_;
+
+    /// @brief TCPAcceptor under test.
+    TestTCPAcceptor acceptor_;
+
+    /// @brief Server endpoint.
+    boost::asio::ip::tcp::endpoint asio_endpoint_;
+
+    /// @brief asiolink server endpont (uses asio_endpoint_).
+    TCPEndpoint endpoint_;
+
+    /// @brief Asynchronous timer service to detect timeouts.
     IntervalTimer test_timer_;
+
+    /// @brief List of connections on the server side.
     std::list<AcceptorPtr> connections_;
+
+    /// @brief List of client connections.
     std::list<TCPClientPtr> clients_;
+
+    /// @brief Current number of established connections.
     unsigned int connections_num_;
+
+    /// @brief Connections limit.
     unsigned int max_connections_;
 };
 
+// Test TCPAcceptor::asyncAccept.
 TEST_F(TCPAcceptorTest, asyncAccept) {
+    // Establish up to 10 connections.
     setMaxConnections(10);
-    TCPEndpoint endpoint(IOAddress("127.0.0.1"), 18123);
-    acceptor_.open(endpoint);
-    acceptor_.bind(endpoint);
+
+    // Initialize acceptor.
+    acceptor_.open(endpoint_);
+    acceptor_.bind(endpoint_);
     acceptor_.listen();
 
+    // Start accepting new connections.
     accept();
 
+    // Create 10 new TCP connections (client side).
     for (unsigned int i = 0; i < 10; ++i) {
         connect();
     }
 
+    // Run the IO service until we have accepted 10 connections, an error
+    // or test timeout occurred.
     io_service_.run();
+
+    // Make sure that all accepted connections have been recorded.
+    EXPECT_EQ(10, connections_num_);
+    EXPECT_EQ(10, connections_.size());
+}
+
+// Check that it is possible to set SO_REUSEADDR flag for the TCPAcceptor.
+TEST_F(TCPAcceptorTest, reuseAddress) {
+    // We need at least two acceptors using common address. Let's create the
+    // second endpoint which has the same address but different port.
+    boost::asio::ip::tcp::endpoint asio_endpoint2(createSiblingEndpoint(asio_endpoint_));
+    TCPEndpoint endpoint2(asio_endpoint2);
+
+    // Create and open two acceptors.
+    TestTCPAcceptor acceptor1(io_service_);
+    TestTCPAcceptor acceptor2(io_service_);
+    ASSERT_NO_THROW(acceptor1.open(endpoint_));
+    ASSERT_NO_THROW(acceptor2.open(endpoint2));
+
+    // Set SO_REUSEADDR socket option so as acceptors can bind to the
+    /// same address.
+    ASSERT_NO_THROW(
+        acceptor1.setOption(TestTCPAcceptor::ReuseAddress(true))
+    );
+    ASSERT_NO_THROW(
+        acceptor2.setOption(TestTCPAcceptor::ReuseAddress(true))
+    );
+    ASSERT_NO_THROW(acceptor1.bind(endpoint_));
+    ASSERT_NO_THROW(acceptor2.bind(endpoint2));
+
+    // Create third acceptor, but don't set the SO_REUSEADDR. It should
+    // refuse to bind.
+    TCPEndpoint endpoint3(createSiblingEndpoint(asio_endpoint2));
+    TestTCPAcceptor acceptor3(io_service_);
+    ASSERT_NO_THROW(acceptor3.open(endpoint3));
+    EXPECT_THROW(acceptor3.bind(endpoint_), boost::system::system_error);
+}
+
+// Test that TCPAcceptor::getProtocol returns IPPROTO_TCP.
+TEST_F(TCPAcceptorTest, getProtocol) {
+    EXPECT_EQ(IPPROTO_TCP, acceptor_.getProtocol());
+}
+
+// Test that TCPAcceptor::getNative returns valid socket descriptor.
+TEST_F(TCPAcceptorTest, getNative) {
+    // Initially the descriptor should be invalid (negative).
+    ASSERT_LT(acceptor_.getNative(), 0);
+    // Now open the socket and make sure the returned descriptor is now valid.
+    ASSERT_NO_THROW(acceptor_.open(endpoint_));
+    EXPECT_GE(acceptor_.getNative(), 0);
 }
 
 }