Implement keepalive over session long TCP connection

Author: softins

src/client.cpp

@@ -255,7 +255,8 @@ void CClient::OnSendCLProtMessage ( CHostAddress InetAddr, CVector<uint8_t> vecM
 {
     if ( pTcpConnection )
     {
-        qWarning() << "Client send cannot use TCP server";
+        // already have TCP connection - just send and return
+        pTcpConnection->write ( (const char*) &( (CVector<uint8_t>) vecMessage )[0], vecMessage.Size() );
         return;
     }
 
@@ -284,6 +285,7 @@ void CClient::OnSendCLProtMessage ( CHostAddress InetAddr, CVector<uint8_t> vecM
             CTcpConnection* pTcpConnection = new CTcpConnection ( pSocket,
                                                                   InetAddr,
                                                                   nullptr,
+                                                                  this,
                                                                   &Channel,
                                                                   eProtoMode == PROTO_TCP_LONG ); // client connection, will self-delete on disconnect
 

src/client.h

@@ -469,6 +469,12 @@ protected slots:
     void OnConClientListMesReceived ( CVector<CChannelInfo> vecChanInfo );
     void OnCLConnClientsListMesReceived ( CHostAddress InetAddr, CVector<CChannelInfo> vecChanInfo, CTcpConnection* pTcpConnection );
 
+public slots:
+    void OnCLSendEmptyMes ( CHostAddress InetAddr, CTcpConnection* pTcpConnection )
+    {
+        ConnLessProtocol.CreateCLEmptyMes ( InetAddr, pTcpConnection );
+    }
+
 signals:
     void ConClientListMesReceived ( CVector<CChannelInfo> vecChanInfo );
     void ChatTextReceived ( QString strChatText );

src/tcpconnection.cpp

@@ -24,12 +24,19 @@
 
 #include "protocol.h"
 #include "server.h"
+#include "client.h"
 #include "channel.h"
 
-CTcpConnection::CTcpConnection ( QTcpSocket* pTcpSocket, const CHostAddress& tcpAddress, CServer* pServer, CChannel* pChannel, bool bIsSession ) :
+CTcpConnection::CTcpConnection ( QTcpSocket*         pTcpSocket,
+                                 const CHostAddress& tcpAddress,
+                                 CServer*            pServer,
+                                 CClient*            pClient,
+                                 CChannel*           pChannel,
+                                 bool                bIsSession ) :
     pTcpSocket ( pTcpSocket ),
     tcpAddress ( tcpAddress ),
     pServer ( pServer ),
+    pClient ( pClient ),
     pChannel ( pChannel ),
     bIsSession ( bIsSession )
 {
@@ -49,11 +56,20 @@ CTcpConnection::CTcpConnection ( QTcpSocket* pTcpSocket, const CHostAddress& tcp
     {
         connect ( this, &CTcpConnection::ProtocolCLMessageReceived, pChannel, &CChannel::OnProtocolCLMessageReceived );
     }
+
+    if ( pClient && bIsSession )
+    {
+        // set up keepalive CLM_EMPTY_MESSAGE over TCP session connection
+        connect ( this, &CTcpConnection::CLSendEmptyMes, pClient, &CClient::OnCLSendEmptyMes );
+        connect ( &TimerKeepalive, &QTimer::timeout, this, &CTcpConnection::OnTimerKeepalive );
+        TimerKeepalive.start ( TCP_KEEPALIVE_INTERVAL_MS );
+    }
 }
 
 void CTcpConnection::OnDisconnected()
 {
     qDebug() << "- Jamulus-TCP: disconnected from:" << tcpAddress.toString();
+    TimerKeepalive.stop();
     pTcpSocket->deleteLater();
     if ( pChannel && pChannel->GetTcpConnection() == this )
     {
@@ -160,6 +176,12 @@ void CTcpConnection::OnReadyRead()
     qDebug() << "- end of readyRead(), bytesAvailable() =" << pTcpSocket->bytesAvailable();
 }
 
+void CTcpConnection::OnTimerKeepalive()
+{
+    // qDebug() << "- Keepalive timer" << this << "to TCP" << tcpAddress.toString();
+    emit CLSendEmptyMes ( tcpAddress, this );
+}
+
 qint64 CTcpConnection::write ( const char* data, qint64 maxSize )
 {
     if ( !pTcpSocket )

src/tcpconnection.h

@@ -40,13 +40,20 @@
 class CServer;  // forward declaration of CServer
 class CChannel; // forward declaration of CChannel
 
+#define TCP_KEEPALIVE_INTERVAL_MS 15000
+
 /* Classes ********************************************************************/
 class CTcpConnection : public QObject
 {
     Q_OBJECT
 
 public:
-    CTcpConnection ( QTcpSocket* pTcpSocket, const CHostAddress& tcpAddress, CServer* pServer, CChannel* pChannel, bool bIsSession );
+    CTcpConnection ( QTcpSocket*         pTcpSocket,
+                     const CHostAddress& tcpAddress,
+                     CServer*            pServer,
+                     CClient*            pClient,
+                     CChannel*           pChannel,
+                     bool                bIsSession );
     ~CTcpConnection() {}
 
     void      SetChannel ( CChannel* pChan ) { pChannel = pChan; }
@@ -63,6 +70,7 @@ class CTcpConnection : public QObject
     CHostAddress udpAddress;
 
     CServer*  pServer;
+    CClient*  pClient;
     CChannel* pChannel;
 
     const bool bIsSession;
@@ -71,10 +79,14 @@ class CTcpConnection : public QObject
     int              iPayloadRemain;
     CVector<uint8_t> vecbyRecBuf;
 
+    QTimer TimerKeepalive;
+
 signals:
     void ProtocolCLMessageReceived ( int iRecID, CVector<uint8_t> vecbyMesBodyData, CHostAddress HostAdr, CTcpConnection* pTcpConnection );
+    void CLSendEmptyMes ( CHostAddress InetAddr, CTcpConnection* pTcpConnection );
 
 private slots:
     void OnDisconnected();
     void OnReadyRead();
+    void OnTimerKeepalive();
 };

src/tcpserver.cpp

@@ -97,5 +97,5 @@ void CTcpServer::OnNewConnection()
 
     qDebug() << "- Jamulus-TCP: received connection from:" << peerAddress.toString();
 
-    new CTcpConnection ( pSocket, peerAddress, pServer, nullptr, false ); // will auto-delete on disconnect
+    new CTcpConnection ( pSocket, peerAddress, pServer, nullptr, nullptr, false ); // will auto-delete on disconnect
 }