From 74a2d985ebb1fd6a985d1d516e79b67102557a43 Mon Sep 17 00:00:00 2001
From: Stephen Birarda <commit@birarda.com>
Date: Fri, 31 Jul 2015 19:17:02 -0700
Subject: [PATCH] tell the send queue about ACKs on light ACK

---
 libraries/networking/src/udt/Connection.cpp | 13 ++++++++-----
 tools/udt-test/src/UDTTest.cpp              |  5 +++--
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/libraries/networking/src/udt/Connection.cpp b/libraries/networking/src/udt/Connection.cpp
index 24911d04cb..8ad7259347 100644
--- a/libraries/networking/src/udt/Connection.cpp
+++ b/libraries/networking/src/udt/Connection.cpp
@@ -102,7 +102,7 @@ void Connection::sendACK(bool wasCausedBySyncTimeout) {
     
     if (nextACKNumber == _lastSentACK) {
         // We already sent this ACK, but check if we should re-send it.
-        if (nextACKNumber <= _lastReceivedAcknowledgedACK) {
+        if (nextACKNumber < _lastReceivedAcknowledgedACK) {
             // we already got an ACK2 for this ACK we would be sending, don't bother
             return;
         }
@@ -375,11 +375,11 @@ void Connection::processACK(std::unique_ptr<ControlPacket> controlPacket) {
     // read the ACKed sequence number
     SequenceNumber ack;
     controlPacket->readPrimitive(&ack);
-
+    
     // validate that this isn't a BS ACK
     if (ack > getSendQueue().getCurrentSequenceNumber()) {
         // in UDT they specifically break the connection here - do we want to do anything?
-        Q_ASSERT_X(true, "Connection::processACK", "ACK recieved higher than largest sent sequence number");
+        Q_ASSERT_X(false, "Connection::processACK", "ACK recieved higher than largest sent sequence number");
         return;
     }
     
@@ -388,7 +388,7 @@ void Connection::processACK(std::unique_ptr<ControlPacket> controlPacket) {
     controlPacket->readPrimitive(&rtt);
     
     if (ack < _lastReceivedACK) {
-        // Bail
+        // this is an out of order ACK, bail
         return;
     }
     
@@ -396,7 +396,7 @@ void Connection::processACK(std::unique_ptr<ControlPacket> controlPacket) {
     controlPacket->readPrimitive(&_flowWindowSize);
     
     if (ack == _lastReceivedACK) {
-        // Bail
+        // processing an already received ACK, bail
         return;
     }
     
@@ -455,6 +455,9 @@ void Connection::processLightACK(std::unique_ptr<ControlPacket> controlPacket) {
     
         // update the last received ACK to the this one
         _lastReceivedACK = ack;
+        
+        // send light ACK to the send queue
+        getSendQueue().ack(ack);
     }
     
     _stats.recordReceivedLightACK();
diff --git a/tools/udt-test/src/UDTTest.cpp b/tools/udt-test/src/UDTTest.cpp
index d0c7b159df..97de033dfe 100644
--- a/tools/udt-test/src/UDTTest.cpp
+++ b/tools/udt-test/src/UDTTest.cpp
@@ -42,7 +42,7 @@ const QCommandLineOption UNRELIABLE_PACKETS {
 };
 
 const QStringList STATS_TABLE_HEADERS {
-    "Send Rate (P/s)", "RTT(ms)", "CW (P)", "Send Period (us)", "Received ACK", "Received NAK", "Sent ACK2"
+    "Send Rate (P/s)", "RTT(ms)", "CW (P)", "Send Period (us)", "Received ACK", "Received NAK", "Sent ACK2", "Re-sent Packets"
 };
 
 UDTTest::UDTTest(int& argc, char** argv) :
@@ -228,7 +228,8 @@ void UDTTest::sampleStats() {
         QString::number(stats.packetSendPeriod).leftJustified(STATS_TABLE_HEADERS[++headerIndex].size()),
         QString::number(stats.receivedACKs).leftJustified(STATS_TABLE_HEADERS[++headerIndex].size()),
         QString::number(stats.receivedNAKs).leftJustified(STATS_TABLE_HEADERS[++headerIndex].size()),
-        QString::number(stats.sentACK2s).leftJustified(STATS_TABLE_HEADERS[++headerIndex].size())
+        QString::number(stats.sentACK2s).leftJustified(STATS_TABLE_HEADERS[++headerIndex].size()),
+        QString::number(stats.retransmissions).leftJustified(STATS_TABLE_HEADERS[++headerIndex].size())
     };
     
     // output this line of values