[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <1439837957-673905-4-git-send-email-tom@herbertland.com>
Date: Mon, 17 Aug 2015 11:59:16 -0700
From: Tom Herbert <tom@...bertland.com>
To: <davem@...emloft.net>, <netdev@...r.kernel.org>
CC: <kernel-team@...com>
Subject: [PATCH net-next v3 3/4] net: Add inet_proto_csum_replace_by_diff utility function
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@...bertland.com>
---
include/net/checksum.h | 2 ++
net/core/utils.c | 13 +++++++++++++
2 files changed, 15 insertions(+)
diff --git a/include/net/checksum.h b/include/net/checksum.h
index 619f344..9fcaedf 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,
bool pseudohdr);
+void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
+ __wsum diff, bool 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 cd7d202..3dffce9 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, bool 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;
--
1.8.1
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists