Add ability to reconnect from server side (#7226)

* Add ability to reconnect from server side

* Fix code smell

Co-authored-by: Serhii Hadzhilov <serhii@symless.com>

src/lib/net/InverseSockets/InverseServerSocket.cpp

@@ -51,7 +51,8 @@ void
 InverseServerSocket::bind(const NetworkAddress& addr)
 {
     Lock lock(&m_mutex);
-    m_socket.connectSocket(addr);
+    m_address = addr;
+    m_socket.connectSocket(m_address);
     setListeningJob(true);
 }
 
@@ -110,8 +111,8 @@ InverseServerSocket::serviceListening(ISocketMultiplexerJob* job,
                             bool, bool write, bool error)
 {
     if (error) {
-        close();
+        m_socket.connectSocket(m_address);
-        return nullptr;
+        return job;
     }
     if (write) {
         m_events->addEvent(Event(m_events->forIListenSocket().connecting(), this));

src/lib/net/InverseSockets/InverseServerSocket.h

@@ -58,4 +58,7 @@ protected:
     Mutex               m_mutex;
     IEventQueue*        m_events;
     SocketMultiplexer*  m_socketMultiplexer;
+
+private:
+    NetworkAddress      m_address;
 };

src/lib/net/SecureSocket.cpp

@@ -403,17 +403,20 @@ SecureSocket::freeSSL()
     // could cause events to get called on a dead object. TCPSocket
     // will do this, too, but the double-call is harmless
     setJob(NULL);
-    if (m_ssl->m_ssl != NULL) {
+    if (m_ssl) {
-        SSL_shutdown(m_ssl->m_ssl);
+        if (m_ssl->m_ssl != NULL) {
+            SSL_shutdown(m_ssl->m_ssl);
 
-        SSL_free(m_ssl->m_ssl);
+            SSL_free(m_ssl->m_ssl);
-        m_ssl->m_ssl = NULL;
+            m_ssl->m_ssl = NULL;
+        }
+        if (m_ssl->m_context != NULL) {
+            SSL_CTX_free(m_ssl->m_context);
+            m_ssl->m_context = NULL;
+        }
+        delete m_ssl;
+        m_ssl = nullptr;
     }
-    if (m_ssl->m_context != NULL) {
-        SSL_CTX_free(m_ssl->m_context);
-        m_ssl->m_context = NULL;
-    }
-    delete m_ssl;
 }
 
 int

src/lib/server/ClientListener.cpp

@@ -40,22 +40,13 @@ ClientListener::ClientListener(const NetworkAddress& address,
     m_socketFactory(socketFactory),
     m_server(NULL),
     m_events(events),
-    m_useSecureNetwork(enableCrypto)
+    m_useSecureNetwork(enableCrypto),
+    m_address(address)
 {
     assert(m_socketFactory != NULL);
 
     try {
-        m_listen = m_socketFactory->createListen(m_useSecureNetwork, ARCH->getAddrFamily(address.getAddress()));
+        start();
-
-        // setup event handler
-        m_events->adoptHandler(m_events->forIListenSocket().connecting(),
-                    m_listen,
-                    new TMethodEventJob<ClientListener>(this,
-                            &ClientListener::handleClientConnecting));
-        
-        // bind listen address
-        LOG((CLOG_DEBUG1 "binding listen socket"));
-        m_listen->bind(address);
     }
     catch (XSocketAddressInUse&) {
         cleanupListenSocket();
@@ -72,31 +63,7 @@ ClientListener::ClientListener(const NetworkAddress& address,
 
 ClientListener::~ClientListener()
 {
-    LOG((CLOG_DEBUG1 "stop listening for clients"));
+    stop();
-
-    // discard already connected clients
-    for (NewClients::iterator index = m_newClients.begin();
-                                index != m_newClients.end(); ++index) {
-        ClientProxyUnknown* client = *index;
-        m_events->removeHandler(
-                            m_events->forClientProxyUnknown().success(), client);
-        m_events->removeHandler(
-                            m_events->forClientProxyUnknown().failure(), client);
-        m_events->removeHandler(
-                            m_events->forClientProxy().disconnected(), client);
-        delete client;
-    }
-
-    // discard waiting clients
-    ClientProxy* client = getNextClient();
-    while (client != NULL) {
-        delete client;
-        client = getNextClient();
-    }
-
-    m_events->removeHandler(m_events->forIListenSocket().connecting(), m_listen);
-    cleanupListenSocket();
-    cleanupClientSockets();
     delete m_socketFactory;
 }
 
@@ -119,6 +86,56 @@ ClientListener::getNextClient()
     return client;
 }
 
+void ClientListener::start()
+{
+    m_listen = m_socketFactory->createListen(m_useSecureNetwork, ARCH->getAddrFamily(m_address.getAddress()));
+
+    // setup event handler
+    m_events->adoptHandler(m_events->forIListenSocket().connecting(),
+                m_listen,
+                new TMethodEventJob<ClientListener>(this,
+                        &ClientListener::handleClientConnecting));
+
+    // bind listen address
+    LOG((CLOG_DEBUG1 "binding listen socket"));
+    m_listen->bind(m_address);
+}
+
+void ClientListener::stop()
+{
+    LOG((CLOG_DEBUG1 "stop listening for clients"));
+
+    // discard already connected clients
+    for (NewClients::iterator index = m_newClients.begin();
+                                index != m_newClients.end(); ++index) {
+        ClientProxyUnknown* client = *index;
+        m_events->removeHandler(
+                            m_events->forClientProxyUnknown().success(), client);
+        m_events->removeHandler(
+                            m_events->forClientProxyUnknown().failure(), client);
+        m_events->removeHandler(
+                            m_events->forClientProxy().disconnected(), client);
+        delete client;
+    }
+
+    // discard waiting clients
+    ClientProxy* client = getNextClient();
+    while (client != nullptr) {
+        delete client;
+        client = getNextClient();
+    }
+
+    m_events->removeHandler(m_events->forIListenSocket().connecting(), m_listen);
+    cleanupListenSocket();
+    cleanupClientSockets();
+}
+
+void ClientListener::restart()
+{
+    stop();
+    start();
+}
+
 void
 ClientListener::handleClientConnecting(const Event&, void*)
 {

src/lib/server/ClientListener.h

@@ -66,7 +66,10 @@ public:
     ClientProxy*        getNextClient();
 
     //! Get server which owns this listener
-    Server*                getServer() { return m_server; }
+    Server*             getServer() { return m_server; }
+
+    //! This method restarts the listener
+    void                restart();
 
     //@}
 
@@ -79,6 +82,8 @@ private:
 
     void                cleanupListenSocket();
     void                cleanupClientSockets();
+    void                start();
+    void                stop();
 
 private:
     typedef std::set<ClientProxyUnknown*> NewClients;
@@ -93,4 +98,5 @@ private:
     IEventQueue*        m_events;
     bool                m_useSecureNetwork;
     ClientSockets      m_clientSockets;
+    NetworkAddress     m_address;
 };

src/lib/server/Config.cpp

@@ -658,6 +658,11 @@ String Config::getClientAddress() const
 	return m_clientAddress;
 }
 
+bool Config::isClientMode() const
+{
+	return (!m_clientAddress.empty());
+}
+
 void
 Config::readSection(ConfigReadContext& s)
 {

src/lib/server/Config.h

@@ -455,6 +455,13 @@ public:
      * Return client address a string.
      */
     String               getClientAddress() const;
+
+    //! Return true if server started in client mode
+    /*!
+     * In client mode the server initiates connection to client
+     */
+    bool                 isClientMode() const;
+
     //@}
 
 private:

src/lib/server/Server.cpp

@@ -1432,6 +1432,10 @@ Server::handleClientDisconnected(const Event&, void* vclient)
 	removeOldClient(client);
 
 	delete client;
+
+	if (m_args.m_config->isClientMode()) {
+		m_clientListener->restart();
+	}
 }
 
 void

src/lib/synergy/ServerApp.cpp

@@ -682,13 +682,12 @@ ServerApp::handleScreenSwitched(const Event& e, void*)
 ISocketFactory* ServerApp::getSocketFactory() const
 {
     ISocketFactory* socketFactory = nullptr;
-    const auto clientAddress = args().m_config->getClientAddress();
 
-    if (clientAddress.empty()) {
+    if (args().m_config->isClientMode()) {
-        socketFactory = new TCPSocketFactory(m_events, getSocketMultiplexer());
+        socketFactory = new InverseSocketFactory(m_events, getSocketMultiplexer());
     }
     else {
-        socketFactory = new InverseSocketFactory(m_events, getSocketMultiplexer());
+        socketFactory = new TCPSocketFactory(m_events, getSocketMultiplexer());
     }
 
     return socketFactory;
@@ -696,15 +695,15 @@ ISocketFactory* ServerApp::getSocketFactory() const
 
 NetworkAddress ServerApp::getAddress(const NetworkAddress& address) const
 {
-    const auto clientAddress = args().m_config->getClientAddress();
+    if (args().m_config->isClientMode()) {
-    if (clientAddress.empty()) {
+        const auto clientAddress = args().m_config->getClientAddress();
-        return address;
-    }
-    else {
         NetworkAddress addr(clientAddress.c_str(), kDefaultPort);
         addr.resolve();
         return addr;
     }
+    else {
+        return address;
+    }
 }
 
 int