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[net-next,v2,2/3] net: Add inet_proto_csum_replace_by_diff utility function

Message ID 1439830611-22898-3-git-send-email-tom@herbertland.com
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Tom Herbert Aug. 17, 2015, 4:56 p.m. UTC 
This function updates a checksum field value and skb->csum based on
a value which is the difference between the old and new checksum.

Signed-off-by: Tom Herbert <tom@herbertland.com>
---
 include/net/checksum.h |  2 ++
 net/core/utils.c       | 13 +++++++++++++
 2 files changed, 15 insertions(+)

Comments

David Miller Aug. 17, 2015, 5:50 p.m. UTC | #1 
From: Tom Herbert <tom@herbertland.com>
Date: Mon, 17 Aug 2015 09:56:50 -0700

> +void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
> +				     __wsum diff, int pseudohdr);
 ...
> +void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
> +				     __wsum diff, int pseudohdr)

Please make 'pseudohdr' a bool.

Thanks.
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diff mbox

Patch

diff --git a/include/net/checksum.h b/include/net/checksum.h
index 2d1d73c..0e0c987 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -144,6 +144,8 @@  void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
 void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
 			       const __be32 *from, const __be32 *to,
 			       int pseudohdr);
+void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
+				     __wsum diff, int pseudohdr);
 
 static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
 					    __be16 from, __be16 to,
diff --git a/net/core/utils.c b/net/core/utils.c
index a7732a0..89ccfb1 100644
--- a/net/core/utils.c
+++ b/net/core/utils.c
@@ -336,6 +336,19 @@  void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
 }
 EXPORT_SYMBOL(inet_proto_csum_replace16);
 
+void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
+				     __wsum diff, int pseudohdr)
+{
+	if (skb->ip_summed != CHECKSUM_PARTIAL) {
+		*sum = csum_fold(csum_add(diff, ~csum_unfold(*sum)));
+		if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
+			skb->csum = ~csum_add(diff, ~skb->csum);
+	} else if (pseudohdr) {
+		*sum = ~csum_fold(csum_add(diff, csum_unfold(*sum)));
+	}
+}
+EXPORT_SYMBOL(inet_proto_csum_replace_by_diff);
+
 struct __net_random_once_work {
 	struct work_struct work;
 	struct static_key *key;