Inter-frame sleep time calculation can generate invalid sleep time

[merose]

What is observed when running the SLE bridge and sending a CLTU:

Exception in thread "Thread-2" java.lang.IllegalArgumentException: nanosecond timeout value out of range
	at java.lang.Thread.sleep(Thread.java:332)
	at org.yamcs.sle.udpslebridge.UdpCltuUplinker.uplink(UdpCltuUplinker.java:54)
	at org.yamcs.sle.provider.CltuServiceProvider.uplinkCltu(CltuServiceProvider.java:438)
	at org.yamcs.sle.provider.CltuServiceProvider.runUplinkQueue(CltuServiceProvider.java:426)
	at org.yamcs.sle.provider.CltuServiceProvider.lambda$processStartInvocation$0(CltuServiceProvider.java:152)
	at java.lang.Thread.run(Thread.java:748)

This appears to be caused by insufficient precision in the sleep duration calculation:

        long durationNs = cltuData.length * 8 * 1000_000_000 / bitrate;
        int millis = (int) (durationNs / 1000_000);
        int nanos = (int) (durationNs % 1000_000);

The problem is that cltuData.length is of type int, as are all the operands: two constants 8 and 1000_000_000, and the bitrate. This causes the multiplication and division on the right-hand side to use int precision, which can overflow and generate a negative value for durationNs.

The easiest way to fix this is to change the constants to long type:

        long durationNs = cltuData.length * 8L * 1000_000_000L / bitrate;
        int millis = (int) (durationNs / 1000_000);
        int nanos = (int) (durationNs % 1000_000);

[merose]

A patch file for the change.

diff --git a/src/main/java/org/yamcs/sle/udpslebridge/UdpCltuUplinker.java b/src/main/java/org/yamcs/sle/udpslebridge/UdpCltuUplinker.java
index 0e73e60f9e..d2202651f7 100644
--- a/src/main/java/org/yamcs/sle/udpslebridge/UdpCltuUplinker.java
+++ b/src/main/java/org/yamcs/sle/udpslebridge/UdpCltuUplinker.java
@@ -6,7 +6,6 @@ import java.net.DatagramSocket;
 import java.net.InetAddress;
 import java.util.logging.Level;
 import java.util.logging.Logger;
-
 import org.yamcs.sle.CcsdsTime;
 import org.yamcs.sle.Constants.ForwardDuStatus;
 import org.yamcs.sle.provider.CltuUplinker;
@@ -46,7 +45,7 @@ public class UdpCltuUplinker implements CltuUplinker {
 
         DatagramPacket dtg = new DatagramPacket(cltuData, cltuData.length, address, port);
         ur.startTime = CcsdsTime.now();
-        long durationNs = cltuData.length * 8 * 1000_000_000 / bitrate;
+        long durationNs = cltuData.length * 8L * 1000_000_000L / bitrate;
         int millis = (int) (durationNs / 1000_000);
         int nanos = (int) (durationNs % 1000_000);

[xpromache]

Implemented on master, thanks!