fix ATP SendQueue failure to receive after re-activity

libraries/networking/src/udt/Connection.cpp

@@ -82,8 +82,12 @@ void Connection::resetRTT() {
 
 SendQueue& Connection::getSendQueue() {
     if (!_sendQueue) {
+
+        // we may have a sequence number from the previous inactive queue - re-use that so that the
+        // receiver is getting the sequence numbers it expects (given that the connection must still be active)
+
         // Lasily create send queue
-        _sendQueue = SendQueue::create(_parentSocket, _destination);
+        _sendQueue = SendQueue::create(_parentSocket, _destination, _inactiveSendQueueSequenceNumber);
 
 #ifdef UDT_CONNECTION_DEBUG
         qCDebug(networking) << "Created SendQueue for connection to" << _destination;
@@ -105,6 +109,10 @@ SendQueue& Connection::getSendQueue() {
 }
 
 void Connection::queueInactive() {
+    // get the current sequence number from the send queue, this is to be re-used if the send
+    // queue is re-activated for this connection
+    _inactiveSendQueueSequenceNumber = _sendQueue->getCurrentSequenceNumber();
+
     // tell our current send queue to go down and reset our ptr to it to null
     stopSendQueue();
     

libraries/networking/src/udt/Connection.h

@@ -139,6 +139,8 @@ private:
     
     SequenceNumber _lastSentACK; // The last sent ACK
     SequenceNumber _lastSentACK2; // The last sent ACK sub-sequence number in an ACK2
+
+    SequenceNumber _inactiveSendQueueSequenceNumber { 0 };
    
     int _acksDuringSYN { 1 }; // The number of non-SYN ACKs sent during SYN
     int _lightACKsDuringSYN { 1 }; // The number of lite ACKs sent during SYN interval

libraries/networking/src/udt/SendQueue.cpp

@@ -52,11 +52,11 @@ private:
     Mutex2& _mutex2;
 };
 
-std::unique_ptr<SendQueue> SendQueue::create(Socket* socket, HifiSockAddr destination) {
+std::unique_ptr<SendQueue> SendQueue::create(Socket* socket, HifiSockAddr destination, SequenceNumber currentSequenceNumber) {
     Q_ASSERT_X(socket, "SendQueue::create", "Must be called with a valid Socket*");
     
-    auto queue = std::unique_ptr<SendQueue>(new SendQueue(socket, destination));
+    auto queue = std::unique_ptr<SendQueue>(new SendQueue(socket, destination, currentSequenceNumber));
-    
+
     // Setup queue private thread
     QThread* thread = new QThread;
     thread->setObjectName("Networking: SendQueue " + destination.objectName()); // Name thread for easier debug
@@ -74,10 +74,12 @@ std::unique_ptr<SendQueue> SendQueue::create(Socket* socket, HifiSockAddr destin
     return queue;
 }
     
-SendQueue::SendQueue(Socket* socket, HifiSockAddr dest) :
+SendQueue::SendQueue(Socket* socket, HifiSockAddr dest, SequenceNumber currentSequenceNumber) :
     _socket(socket),
-    _destination(dest)
+    _destination(dest),
+    _currentSequenceNumber(currentSequenceNumber)
 {
+    
 }
 
 void SendQueue::queuePacket(std::unique_ptr<Packet> packet) {
@@ -389,6 +391,7 @@ bool SendQueue::isInactive(bool sentAPacket) {
         static const int NUM_TIMEOUTS_BEFORE_INACTIVE = 16;
         static const int MIN_SECONDS_BEFORE_INACTIVE_MS = 5 * 1000;
         if (_timeoutExpiryCount >= NUM_TIMEOUTS_BEFORE_INACTIVE &&
+            _lastReceiverResponse > 0 &&
             (QDateTime::currentMSecsSinceEpoch() - _lastReceiverResponse) > MIN_SECONDS_BEFORE_INACTIVE_MS) {
             // If the flow window has been full for over CONSIDER_INACTIVE_AFTER,
             // then signal the queue is inactive and return so it can be cleaned up

libraries/networking/src/udt/SendQueue.h

@@ -50,7 +50,8 @@ public:
         Stopped
     };
     
-    static std::unique_ptr<SendQueue> create(Socket* socket, HifiSockAddr destination);
+    static std::unique_ptr<SendQueue> create(Socket* socket, HifiSockAddr destination,
+                                             SequenceNumber currentSequenceNumber = SequenceNumber());
     
     void queuePacket(std::unique_ptr<Packet> packet);
     void queuePacketList(std::unique_ptr<PacketList> packetList);
@@ -83,7 +84,7 @@ private slots:
     void run();
     
 private:
-    SendQueue(Socket* socket, HifiSockAddr dest);
+    SendQueue(Socket* socket, HifiSockAddr dest, SequenceNumber currentSequenceNumber);
     SendQueue(SendQueue& other) = delete;
     SendQueue(SendQueue&& other) = delete;
     
@@ -108,7 +109,7 @@ private:
     
     std::atomic<uint32_t> _lastACKSequenceNumber { 0 }; // Last ACKed sequence number
     
-    SequenceNumber _currentSequenceNumber; // Last sequence number sent out
+    SequenceNumber _currentSequenceNumber { 0 }; // Last sequence number sent out
     std::atomic<uint32_t> _atomicCurrentSequenceNumber { 0 }; // Atomic for last sequence number sent out
     
     std::atomic<int> _packetSendPeriod { 0 }; // Interval between two packet send event in microseconds, set from CC