give CongestionControl timeout event from SendQueue

libraries/networking/src/udt/CongestionControl.cpp

@@ -62,10 +62,10 @@ void DefaultCC::onACK(SequenceNumber ackNum) {
 
     if (_slowStart) {
         // we are in slow start phase - increase the congestion window size by the number of packets just ACKed
-        _congestionWindowSize += seqlen(_slowStartLastACK, ackNum);
+        _congestionWindowSize += seqlen(_lastACK, ackNum);
         
         // update the last ACK
-        _slowStartLastACK = ackNum;
+        _lastACK = ackNum;
 
         // check if we can get out of slow start (is our new congestion window size bigger than the max)
         if (_congestionWindowSize > _maxCongestionWindowSize) {
@@ -186,11 +186,11 @@ void DefaultCC::onTimeout() {
         stopSlowStart();
     } else {
         // UDT used to do the following on timeout if not in slow start - we should check if it could be helpful
-        // _lastDecreasePeriod = _packetSendPeriod;
-        // _packetSendPeriod = ceil(_packetSendPeriod * 2);
-        
+         _lastDecreasePeriod = _packetSendPeriod;
+         _packetSendPeriod = ceil(_packetSendPeriod * 2);
+
         // this seems odd - the last ack they were setting _lastDecreaseMaxSeq to only applies to slow start
-        // _lastDecreaseMaxSeq = _slowStartLastAck;
+         _lastDecreaseMaxSeq = _lastACK;
     }
 }
 
@@ -209,6 +209,5 @@ void DefaultCC::stopSlowStart() {
 }
 
 void DefaultCC::setInitialSendSequenceNumber(udt::SequenceNumber seqNum) {
-    _slowStartLastACK = seqNum;
-    _lastDecreaseMaxSeq = seqNum - 1;
+    _lastACK = _lastDecreaseMaxSeq = seqNum - 1;
 }

libraries/networking/src/udt/CongestionControl.h

@@ -41,7 +41,7 @@ public:
     virtual void init() {}
     virtual void onACK(SequenceNumber ackNum) {}
     virtual void onLoss(SequenceNumber rangeStart, SequenceNumber rangeEnd) {}
-    
+    virtual void onTimeout() {}
 protected:
     void setAckInterval(int ackInterval) { _ackInterval = ackInterval; }
     void setRTO(int rto) { _userDefinedRTO = true; _rto = rto; }
@@ -115,7 +115,7 @@ private:
     p_high_resolution_clock::time_point _lastRCTime = p_high_resolution_clock::now(); // last rate increase time
     
     bool _slowStart { true };	// if in slow start phase
-    SequenceNumber _slowStartLastACK; // last ACKed seq num from previous slow start check
+    SequenceNumber _lastACK; // last ACKed sequence number from previous
     bool _loss { false };	// if loss happened since last rate increase
     SequenceNumber _lastDecreaseMaxSeq; // max pkt seq num sent out when last decrease happened
     double _lastDecreasePeriod { 1 }; // value of _packetSendPeriod when last decrease happened

libraries/networking/src/udt/Connection.cpp

@@ -98,6 +98,7 @@ SendQueue& Connection::getSendQueue() {
         QObject::connect(_sendQueue.get(), &SendQueue::packetSent, this, &Connection::recordSentPackets);
         QObject::connect(_sendQueue.get(), &SendQueue::packetRetransmitted, this, &Connection::recordRetransmission);
         QObject::connect(_sendQueue.get(), &SendQueue::queueInactive, this, &Connection::queueInactive);
+        QObject::connect(_sendQueue.get(), &SendQueue::timeout, this, &Connection::queueTimeout);
         
         // set defaults on the send queue from our congestion control object and estimatedTimeout()
         _sendQueue->setPacketSendPeriod(_congestionControl->_packetSendPeriod);
@@ -129,6 +130,12 @@ void Connection::queueInactive() {
     }
 }
 
+void Connection::queueTimeout() {
+    updateCongestionControlAndSendQueue([this]{
+        _congestionControl->onTimeout();
+    });
+}
+
 void Connection::sendReliablePacket(std::unique_ptr<Packet> packet) {
     Q_ASSERT_X(packet->isReliable(), "Connection::send", "Trying to send an unreliable packet reliably.");
     getSendQueue().queuePacket(std::move(packet));

libraries/networking/src/udt/Connection.h

@@ -84,6 +84,7 @@ private slots:
     void recordSentPackets(int payload, int total);
     void recordRetransmission();
     void queueInactive();
+    void queueTimeout();
     
 private:
     void sendACK(bool wasCausedBySyncTimeout = true);

libraries/networking/src/udt/SendQueue.cpp

@@ -514,6 +514,11 @@ bool SendQueue::isInactive(bool sentAPacket) {
                     
                     // Note that thanks to the DoubleLock we have the _naksLock right now
                     _naks.append(SequenceNumber(_lastACKSequenceNumber) + 1, _currentSequenceNumber);
+
+                    // we have the lock again - time to unlock it
+                    locker.unlock();
+                    
+                    emit timeout();
                 }
             }
         }

libraries/networking/src/udt/SendQueue.h

@@ -78,6 +78,8 @@ signals:
     void packetRetransmitted();
     
     void queueInactive();
+
+    void timeout();
     
 private slots:
     void run();