add initial send sequence number to SendQueue

libraries/networking/src/udt/Connection.cpp

@@ -87,7 +87,7 @@ SendQueue& Connection::getSendQueue() {
         // 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, _inactiveSendQueueSequenceNumber);
+        _sendQueue = SendQueue::create(_parentSocket, _destination);
 
 #ifdef UDT_CONNECTION_DEBUG
         qCDebug(networking) << "Created SendQueue for connection to" << _destination;
@@ -109,10 +109,6 @@ 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

@@ -130,7 +130,9 @@ private:
     
     bool _isReceivingData { false }; // flag used for expiry of receipt portion of connection
     bool _isActive { true }; // flag used for inactivity of connection
-    
+
+    SequenceNumber _initialReceiveSequenceNumber; // Randomized by peer SendQueue on creation, identifies connection during re-connect requests
+
     LossList _lossList; // List of all missing packets
     SequenceNumber _lastReceivedSequenceNumber; // The largest sequence number received from the peer
     SequenceNumber _lastReceivedACK; // The last ACK received
@@ -140,8 +142,6 @@ 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

@@ -12,6 +12,7 @@
 #include "SendQueue.h"
 
 #include <algorithm>
+#include <random>
 #include <thread>
 
 #include <QtCore/QCoreApplication>
@@ -53,10 +54,10 @@ private:
     Mutex2& _mutex2;
 };
 
-std::unique_ptr<SendQueue> SendQueue::create(Socket* socket, HifiSockAddr destination, SequenceNumber currentSequenceNumber) {
+std::unique_ptr<SendQueue> SendQueue::create(Socket* socket, HifiSockAddr destination) {
     Q_ASSERT_X(socket, "SendQueue::create", "Must be called with a valid Socket*");
     
-    auto queue = std::unique_ptr<SendQueue>(new SendQueue(socket, destination, currentSequenceNumber));
+    auto queue = std::unique_ptr<SendQueue>(new SendQueue(socket, destination));
 
     // Setup queue private thread
     QThread* thread = new QThread;
@@ -75,12 +76,23 @@ std::unique_ptr<SendQueue> SendQueue::create(Socket* socket, HifiSockAddr destin
     return queue;
 }
     
-SendQueue::SendQueue(Socket* socket, HifiSockAddr dest, SequenceNumber currentSequenceNumber) :
+SendQueue::SendQueue(Socket* socket, HifiSockAddr dest) :
     _socket(socket),
-    _destination(dest),
-    _currentSequenceNumber(currentSequenceNumber)
+    _destination(dest)
 {
-    
+
+    // setup psuedo-random number generation for all instances of SendQueue
+    static std::random_device rd;
+    static std::mt19937 generator(rd());
+    static std::uniform_int_distribution<> distribution(0, SequenceNumber::MAX);
+
+    // randomize the intial sequence number
+    _initialSequenceNumber = SequenceNumber(distribution(generator));
+
+    // set our member variables from randomized initial number
+    _currentSequenceNumber = _initialSequenceNumber - 1;
+    _atomicCurrentSequenceNumber = uint32_t(_currentSequenceNumber);
+    _lastACKSequenceNumber = uint32_t(_initialSequenceNumber);
 }
 
 void SendQueue::queuePacket(std::unique_ptr<Packet> packet) {

libraries/networking/src/udt/SendQueue.h

@@ -50,8 +50,7 @@ public:
         Stopped
     };
     
-    static std::unique_ptr<SendQueue> create(Socket* socket, HifiSockAddr destination,
-                                             SequenceNumber currentSequenceNumber = SequenceNumber());
+    static std::unique_ptr<SendQueue> create(Socket* socket, HifiSockAddr destination);
     
     void queuePacket(std::unique_ptr<Packet> packet);
     void queuePacketList(std::unique_ptr<PacketList> packetList);
@@ -84,7 +83,7 @@ private slots:
     void run();
     
 private:
-    SendQueue(Socket* socket, HifiSockAddr dest, SequenceNumber currentSequenceNumber);
+    SendQueue(Socket* socket, HifiSockAddr dest);
     SendQueue(SendQueue& other) = delete;
     SendQueue(SendQueue&& other) = delete;
     
@@ -106,6 +105,8 @@ private:
     
     Socket* _socket { nullptr }; // Socket to send packet on
     HifiSockAddr _destination; // Destination addr
+
+    SequenceNumber _initialSequenceNumber; // Randomized on SendQueue creation, identifies connection during re-connect requests
     
     std::atomic<uint32_t> _lastACKSequenceNumber { 0 }; // Last ACKed sequence number