Subject: [PATCH 02/10] net: add skb_checksum_complete_unset

From: Tom Herbert <[email-masked]>
Date: Mon, 20 Apr 2015 14:10:04 -0700

[ Upstream commit 4e18b9adf2f910ec4d30b811a74a5b626e6c6125 ]

This function changes ip_summed to CHECKSUM_NONE if CHECKSUM_COMPLETE
is set. This is called to discard checksum-complete when packet
is being modified and checksum is not pulled for headers in a layer.

Signed-off-by: Tom Herbert <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 include/linux/skbuff.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index f54d665..b5c204c 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3013,6 +3013,18 @@ static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
  */
 #define CHECKSUM_BREAK 76
 
+/* Unset checksum-complete
+ *
+ * Unset checksum complete can be done when packet is being modified
+ * (uncompressed for instance) and checksum-complete value is
+ * invalidated.
+ */
+static inline void skb_checksum_complete_unset(struct sk_buff *skb)
+{
+	if (skb->ip_summed == CHECKSUM_COMPLETE)
+		skb->ip_summed = CHECKSUM_NONE;
+}
+
 /* Validate (init) checksum based on checksum complete.
  *
  * Return values:
-- 
2.3.5