[PATCH 11/19] net: core: add function for incremental IPv6 pseudo header checksum updates

kaber
2012-08-09T20:18:36Z

From: Patrick McHardy <kaber@trash.net>

Add inet_proto_csum_replace16 for incrementally updating IPv6 pseudo header
checksums for IPv6 NAT.

Signed-off-by: Patrick McHardy <kaber@trash.net>
---
include/net/checksum.h | 3 +++
net/core/utils.c | 20 ++++++++++++++++++++
2 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/include/net/checksum.h b/include/net/checksum.h
index ba55d8b..600d1d7 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -109,6 +109,9 @@ static inline void csum_replace2(__sum16 *sum, __be16 from, __be16 to)
struct sk_buff;
extern void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
__be32 from, __be32 to, int pseudohdr);
+extern void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
+ const __be32 *from, const __be32 *to,
+ 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 39895a6..f5613d5 100644
--- a/net/core/utils.c
+++ b/net/core/utils.c
@@ -294,6 +294,26 @@ void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
}
EXPORT_SYMBOL(inet_proto_csum_replace4);

+void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
+ const __be32 *from, const __be32 *to,
+ int pseudohdr)
+{
+ __be32 diff[] = {
+ ~from[0], ~from[1], ~from[2], ~from[3],
+ to[0], to[1], to[2], to[3],
+ };
+ if (skb->ip_summed != CHECKSUM_PARTIAL) {
+ *sum = csum_fold(csum_partial(diff, sizeof(diff),
+ ~csum_unfold(*sum)));
+ if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
+ skb->csum = ~csum_partial(diff, sizeof(diff),
+ ~skb->csum);
+ } else if (pseudohdr)
+ *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
+ csum_unfold(*sum)));
+}
+EXPORT_SYMBOL(inet_proto_csum_replace16);
+
int mac_pton(const char *s, u8 *mac)
{
int i;
--
1.7.1