Setting tag sliver-openvswitch-2.2.90-1

[sliver-openvswitch.git] / lib / csum.c

diff --git a/lib/csum.c b/lib/csum.c
index 98a83de..a9334fe 100644 (file)
--- a/lib/csum.c
+++ b/lib/csum.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010, 2011 Nicira, Inc.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2013 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -112,6 +112,22 @@ recalc_csum32(ovs_be16 old_csum, ovs_be32 old_u32, ovs_be32 new_u32)
                          old_u32 >> 16, new_u32 >> 16);
 }
 
+/* Returns the new checksum for a packet in which the checksum field previously
+ * contained 'old_csum' and in which a field that contained 'old_u32[4]' was
+ * changed to contain 'new_u32[4]'. */
+ovs_be16
+recalc_csum128(ovs_be16 old_csum, ovs_16aligned_be32 old_u32[4],
+               const ovs_be32 new_u32[4])
+{
+    ovs_be16 new_csum = old_csum;
+    int i;
+
+    for (i = 0; i < 4; ++i) {
+        new_csum = recalc_csum32(new_csum,
+                                 get_16aligned_be32(&old_u32[i]), new_u32[i]);
+    }
+    return new_csum;
+}
 #else  /* __CHECKER__ */
 /* Making sparse happy with these functions also makes them unreadable, so
  * don't bother to show it their implementations. */