Ticket #13634: 0006-tcp-rfc-5681-implemented-ideal-timer.patch

src/add-ons/kernel/network/protocols/tcp/TCPEndpoint.cpp

@@ -1379 +1379 @@
     if ((segment.flags & TCP_FLAG_PUSH) != 0)
         fReceiveQueue.SetPushPointer();
 
+    if (fSendUnacknowledged == fSendMax) {
+        TRACE("data received, resetting ideal timer to: %"
+                B_PRIdBIGTIME, fRetransmitTimeout);
+        gStackModule->set_timer(&fRetransmitTimer, fRetransmitTimeout);
+        T(TimerSet(this, "ideal", fRetransmitTimeout));
+    }
+
     return fReceiveQueue.Available() > 0;
 }
 
@@ -2295 +2302 @@
         }
 
         if (fSendUnacknowledged == fSendMax) {
-            TRACE("all acknowledged, cancelling retransmission timer");
-            gStackModule->cancel_timer(&fRetransmitTimer);
-            T(TimerSet(this, "retransmit", -1));
+            TRACE("all acknowledged, cancelling retransmission timer. Using it as ideal timer for: %"
+                B_PRIdBIGTIME, fRetransmitTimeout);
+            gStackModule->set_timer(&fRetransmitTimer, fRetransmitTimeout);
+            T(TimerSet(this, "ideal", fRetransmitTimeout));
 
             fSendTime = 0;
 
@@ -2327 +2335 @@
     if (fState < ESTABLISHED) {
         fRetransmitTimeout = TCP_SYN_RETRANSMIT_TIMEOUT;
         fCongestionWindow = fSendMaxSegmentSize;
+    } else if (fSendUnacknowledged == fSendMax) {
+        TRACE("Ideal timeout");
+        // idle period time out - did not receive any segment for a time equal
+        // to the retransmission timeout
+
+        uint32 initialWindow;
+        if (fSendMaxSegmentSize > 2190)
+            initialWindow = 2 * fSendMaxSegmentSize;
+        else if (fSendMaxSegmentSize > 1095)
+            initialWindow = 3 * fSendMaxSegmentSize;
+        else
+            initialWindow = 4 * fSendMaxSegmentSize;
+
+        fCongestionWindow = min_c(initialWindow, fCongestionWindow);
+        return;
     } else {
         _ResetSlowStart();
         fDuplicateAcknowledgeCount = 0;