commit 96315df974731f95698904f655959a9498d6d12e
Author: Patrick McHardy <kaber@trash.net>
Date:   Mon Apr 5 15:57:40 2010 +0200

    object: fix attribute comparison
    
    Currently two attributes are regarded as different if they are absent in
    both objects to be compared. This is obviously incorrect, change to
    regard objects as different if an attribute is only present on one of
    them or if the attribute data differs.
    
    Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/include/netlink/object-api.h b/include/netlink/object-api.h
index 5877c00..b3337f0 100644
--- a/include/netlink/object-api.h
+++ b/include/netlink/object-api.h
@@ -198,7 +198,18 @@ extern "C" {
  *
  * @return True if the attribute is available, otherwise false is returned.
  */
-#define AVAILABLE(A, B, ATTR)	(((A)->ce_mask & (B)->ce_mask) & (ATTR))
+#define AVAILABLE(A, B, ATTR)		(((A)->ce_mask & (B)->ce_mask) & (ATTR))
+
+/**
+ * Return true if attribute is available in only one of both objects
+ * @arg A		an object
+ * @arg B		another object
+ * @arg ATTR		attribute bit
+ *
+ * @return True if the attribute is available in only one of both objects,
+ * otherwise false is returned.
+ */
+#define AVAILABLE_MISMATCH(A, B, ATTR)	(((A)->ce_mask ^ (B)->ce_mask) & (ATTR))
 
 /**
  * Return true if attributes mismatch
@@ -215,7 +226,8 @@ extern "C" {
  *
  * @return True if the attribute mismatch, or false if they match.
  */
-#define ATTR_MISMATCH(A, B, ATTR, EXPR)	(!AVAILABLE(A, B, ATTR) || (EXPR))
+#define ATTR_MISMATCH(A, B, ATTR, EXPR)	(AVAILABLE_MISMATCH(A, B, ATTR) || \
+					 (AVAILABLE(A, B, ATTR) && (EXPR)))
 
 /**
  * Return attribute bit if attribute does not match