Allow sequenceNumber to wrap from UInt32.MAX to 0

fixes #1346
eclipse-milo · Nov 27, 2024 · e1cdb05 · e1cdb05
1 parent 13a6a8e
commit e1cdb05
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diff --git a/...tack/stack-core/src/main/java/org/eclipse/milo/opcua/stack/core/channel/ChunkDecoder.java b/...tack/stack-core/src/main/java/org/eclipse/milo/opcua/stack/core/channel/ChunkDecoder.java
@@ -537,7 +537,7 @@ static boolean validateSequenceNumber(long lastSequenceNumber, long sequenceNumb
                 return sequenceNumber < 1024 || sequenceNumber == lastSequenceNumber + 1;
             } else if (lastSequenceNumber == UInteger.MAX_VALUE) {
                 // must wrap at this point
-                return sequenceNumber > 0 && sequenceNumber < 1024;
+                return sequenceNumber >= 0 && sequenceNumber < 1024;
             } else {
                 return sequenceNumber == lastSequenceNumber + 1;
             }

diff --git a/.../stack-core/src/test/java/org/eclipse/milo/opcua/stack/core/channel/ChunkDecoderTest.java b/.../stack-core/src/test/java/org/eclipse/milo/opcua/stack/core/channel/ChunkDecoderTest.java
@@ -32,6 +32,11 @@ void validateSequenceNumbers() {
             assertTrue(validateSequenceNumber(UInteger.MAX_VALUE - 1024, i));
         }
 
+        // wrapping around to anything < 1024 is allowed, from UInteger.MAX_VALUE
+        for (int i = 0; i < 1024; i++) {
+            assertTrue(validateSequenceNumber(UInteger.MAX_VALUE, i));
+        }
+
         // wrapping around to >= 1024 is not allowed
         for (int i = 1024; i < 2048; i++) {
             assertFalse(validateSequenceNumber(UInteger.MAX_VALUE - 1024, i));