--- a/jdk/src/share/classes/sun/security/ssl/MAC.java	Fri Oct 29 12:35:07 2010 +0200
+++ b/jdk/src/share/classes/sun/security/ssl/MAC.java	Sat Oct 30 18:39:17 2010 +0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1996, 2007, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -155,6 +155,42 @@
         return compute(type, bb, null, 0, bb.remaining());
     }
 
+    /**
+     * Check whether the sequence number is close to wrap
+     *
+     * Sequence numbers are of type uint64 and may not exceed 2^64-1.
+     * Sequence numbers do not wrap. When the sequence number is near
+     * to wrap, we need to close the connection immediately.
+     */
+    final boolean seqNumOverflow() {
+        /*
+         * Conservatively, we don't allow more records to be generated
+         * when there are only 2^8 sequence numbers left.
+         */
+        return (block != null && mac != null &&
+                block[0] == 0xFF && block[1] == 0xFF &&
+                block[2] == 0xFF && block[3] == 0xFF &&
+                block[4] == 0xFF && block[5] == 0xFF &&
+                block[6] == 0xFF);
+    }
+
+    /*
+     * Check whether to renew the sequence number
+     *
+     * Sequence numbers are of type uint64 and may not exceed 2^64-1.
+     * Sequence numbers do not wrap.  If a TLS
+     * implementation would need to wrap a sequence number, it must
+     * renegotiate instead.
+     */
+    final boolean seqNumIsHuge() {
+        /*
+         * Conservatively, we should ask for renegotiation when there are
+         * only 2^48 sequence numbers left.
+         */
+        return (block != null && mac != null &&
+                block[0] == 0xFF && block[1] == 0xFF);
+    }
+
     // increment the sequence number in the block array
     // it is a 64-bit number stored in big-endian format
     private void incrementSequenceNumber() {