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@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Herbert 2015-08-17 13:42:26 -07:00 committed by David S. Miller
parent 4b048d6d9d
commit abc5d1ff3e
2 changed files with 15 additions and 0 deletions

View File

@ -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,

View File

@ -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;