[5318] Added unit tests for long connections in DHCPv6.

src/bin/dhcp4/tests/ctrl_dhcp4_srv_unittest.cc

@@ -327,8 +327,8 @@ public:
     }
 
     /// @brief Command handler which generates long response
-   static ConstElementPtr longResponseHandler(const std::string&,
-                                              const ConstElementPtr&) {
+    static ConstElementPtr longResponseHandler(const std::string&,
+                                               const ConstElementPtr&) {
         ElementPtr arguments = Element::createList();
         std::string arg = "responseresponseresponseresponseresponseresponse"
             "response";

src/bin/dhcp6/tests/ctrl_dhcp6_srv_unittest.cc

@@ -31,6 +31,8 @@
 #include <sys/ioctl.h>
 #include <cstdlib>
 
+#include <thread>
+
 using namespace std;
 using namespace isc::asiolink;
 using namespace isc::config;
@@ -43,7 +45,31 @@ using namespace isc::test;
 
 namespace {
 
+/// @brief Simple RAII class which stops IO service upon destruction
+/// of the object.
+class IOServiceWork {
+public:
+
+    /// @brief Constructor.
+    ///
+    /// @param io_service Pointer to the IO service to be stopped.
+    IOServiceWork(const IOServicePtr& io_service)
+        : io_service_(io_service) {
+    }
+
+    /// @brief Destructor.
+    ///
+    /// Stops IO service.
+    ~IOServiceWork() {
+        io_service_->stop();
+    }
 
+private:
+
+    /// @brief Pointer to the IO service to be stopped upon destruction.
+    IOServicePtr io_service_;
+
+};
 
 class NakedControlledDhcpv6Srv: public ControlledDhcpv6Srv {
     // "Naked" DHCPv6 server, exposes internal fields
@@ -306,6 +332,18 @@ public:
             ADD_FAILURE() << "Invalid expected status: " << exp_status;
         }
     }
+
+    /// @brief Command handler which generates long response
+    static ConstElementPtr longResponseHandler(const std::string&,
+                                               const ConstElementPtr&) {
+        ElementPtr arguments = Element::createList();
+        std::string arg = "responseresponseresponseresponseresponseresponse"
+            "response";
+        for (unsigned i = 0; i < 8000; ++i) {
+            arguments->add(Element::create(arg));
+        }
+        return (createAnswer(0, arguments));
+    }
 };
 
 
@@ -1131,5 +1169,205 @@ TEST_F(CtrlChannelDhcpv6SrvTest, concurrentConnections) {
     ASSERT_NO_THROW(getIOService()->poll());
 }
 
+// This test verifies that the server can receive and process a large command.
+TEST_F(CtrlChannelDhcpv6SrvTest, longCommand) {
+    createUnixChannelServer();
+
+    std::string response;
+    std::thread th([this, &response]() {
+
+        // IO service will be stopped automatically when this object goes
+        // out of scope and is destroyed. This is useful because we use
+        // asserts which may break the thread in various exit points.
+        IOServiceWork work(getIOService());
+
+        // Create client which we will use to send command to the server.
+        boost::scoped_ptr<UnixControlClient> client(new UnixControlClient());
+        ASSERT_TRUE(client);
+
+        // Connect to the server. This will trigger acceptor handler on the
+        // server side and create a new connection.
+        ASSERT_TRUE(client->connectToServer(socket_path_));
+
+        // This counter will hold the number of bytes transferred to the server
+        // so far.
+        size_t bytes_transferred = 0;
+        // This is the desired size of the command sent to the server (1MB). The
+        // actual size sent will be slightly greater than that.
+        const size_t command_size = 1024 * 1000;
+        bool first_payload = true;
+
+        // If we still haven't sent the entire command, continue sending.
+        while (bytes_transferred < command_size) {
+
+            // We're sending command 'foo' with arguments being a list of
+            // strings. If this is the first transmission, send command name
+            // and open the arguments list.
+            if (bytes_transferred == 0) {
+                std::string preamble = "{ \"command\": \"foo\", \"arguments\": [ ";
+                ASSERT_TRUE(client->sendCommand(preamble));
+                // Store the number of bytes sent.
+                bytes_transferred += preamble.size();
+
+            } else {
+                // We have already transmitted command name and arguments. Now
+                // we send the list of 'blabla' strings.
+                std::ostringstream payload;
+                // If this is not the first parameter in on the list it must be
+                // prefixed with a comma.
+                if (!first_payload) {
+                    payload << ", ";
+                }
+
+                first_payload = false;
+                payload << "\"blablablablablablablablablablablablablablablabla\"";
+
+                // If we have hit the limit of the command size, close braces to
+                // get appropriate JSON.
+                if (bytes_transferred + payload.tellp() > command_size) {
+                    payload << "] }";
+                }
+                // Send the payload.
+                ASSERT_TRUE(client->sendCommand(payload.str()));
+                // Update the number of bytes sent.
+                bytes_transferred += payload.tellp();
+            }
+
+        }
+
+        // Set timeout to 5 seconds to allow the time for the server to send
+        // a response.
+        const unsigned int timeout = 5;
+        ASSERT_TRUE(client->getResponse(response, timeout));
+
+        // We're done. Close the connection to the server.
+        client->disconnectFromServer();
+    });
+
+    // Run the server until the command has been processed and response
+    // received.
+    getIOService()->run();
+
+    // Wait for the thread to complete.
+    th.join();
+
+    EXPECT_EQ("{ \"result\": 2, \"text\": \"'foo' command not supported.\" }",
+              response);
+}
+
+// This test verifies that the server can send long response to the client.
+TEST_F(CtrlChannelDhcpv6SrvTest, longResponse) {
+    // We need to generate large response. The simplest way is to create
+    // a command and a handler which will generate some static response
+    // of a desired size.
+    ASSERT_NO_THROW(
+        CommandMgr::instance().registerCommand("foo",
+             boost::bind(&CtrlChannelDhcpv6SrvTest::longResponseHandler, _1, _2));
+    );
+
+    createUnixChannelServer();
+
+    // The UnixControlClient doesn't have any means to check that the entire
+    // response has been received. What we want to do is to generate a
+    // reference response using our command handler and then compare
+    // what we have received over the unix domain socket with this reference
+    // response to figure out when to stop receiving.
+    std::string reference_response = longResponseHandler("foo", ConstElementPtr())->str();
+
+    // In this stream we're going to collect out partial responses.
+    std::ostringstream response;
+
+    // The client is synchronous so it is useful to run it in a thread.
+    std::thread th([this, &response, reference_response]() {
+
+        // IO service will be stopped automatically when this object goes
+        // out of scope and is destroyed. This is useful because we use
+        // asserts which may break the thread in various exit points.
+        IOServiceWork work(getIOService());
+
+        // Remember the response size so as we know when we should stop
+        // receiving.
+        const size_t long_response_size = reference_response.size();
+
+        // Create the client and connect it to the server.
+        boost::scoped_ptr<UnixControlClient> client(new UnixControlClient());
+        ASSERT_TRUE(client);
+        ASSERT_TRUE(client->connectToServer(socket_path_));
+
+        // Send the stub command.
+        std::string command = "{ \"command\": \"foo\", \"arguments\": { }  }";
+        ASSERT_TRUE(client->sendCommand(command));
+
+        // Keep receiving response data until we have received the full answer.
+        while (response.tellp() < long_response_size) {
+            std::string partial;
+            const unsigned int timeout = 5;
+            ASSERT_TRUE(client->getResponse(partial, 5));
+            response << partial;
+        }
+
+        // We have received the entire response, so close the connection and
+        // stop the IO service.
+        client->disconnectFromServer();
+    });
+
+    // Run the server until the entire response has been received.
+    getIOService()->run();
+
+    // Wait for the thread to complete.
+    th.join();
+
+    // Make sure we have received correct response.
+    EXPECT_EQ(reference_response, response.str());
+}
+
+// This test verifies that the server signals timeout if the transmission
+// takes too long.
+TEST_F(CtrlChannelDhcpv6SrvTest, connectionTimeout) {
+    createUnixChannelServer();
+
+    // Server's response will be assigned to this variable.
+    std::string response;
+
+    // It is useful to create a thread and run the server and the client
+    // at the same time and independently.
+    std::thread th([this, &response]() {
+
+        // IO service will be stopped automatically when this object goes
+        // out of scope and is destroyed. This is useful because we use
+        // asserts which may break the thread in various exit points.
+        IOServiceWork work(getIOService());
+
+        // Create the client and connect it to the server.
+        boost::scoped_ptr<UnixControlClient> client(new UnixControlClient());
+        ASSERT_TRUE(client);
+        ASSERT_TRUE(client->connectToServer(socket_path_));
+
+        // Send partial command. The server will be waiting for the remaining
+        // part to be sent and will eventually signal a timeout.
+        std::string command = "{ \"command\": \"foo\" ";
+        ASSERT_TRUE(client->sendCommand(command));
+
+        // Let's wait up to 10s for the server's response. The response
+        // should arrive sooner assuming that the timeout mechanism for
+        // the server is working properly.
+        const unsigned int timeout = 10;
+        ASSERT_TRUE(client->getResponse(response, 10));
+
+        // Explicitly close the client's connection.
+        client->disconnectFromServer();
+    });
+
+    // Run the server until stopped.
+    getIOService()->run();
+
+    // Wait for the thread to return.
+    th.join();
+
+    // Check that the server has signalled a timeout.
+    EXPECT_EQ("{ \"result\": 1, \"text\": \"Connection over control channel"
+              " timed out\" }", response);
+}
+
 
 } // End of anonymous namespace