@@ -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,
@@ -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;
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(+)