netfilter: nft_hash: Add hash offset value

Add support to pass through an offset to the hash value. With this
feature, the sysadmin is able to generate a hash with a given
offset value.

Example:

	meta mark set jhash ip saddr mod 2 seed 0xabcd offset 100

This option generates marks according to the source address from 100 to
101.

Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 24161e25576d..8c653bbd1ead 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -731,6 +731,7 @@ enum nft_meta_keys {
  * @NFTA_HASH_LEN: source data length (NLA_U32)
  * @NFTA_HASH_MODULUS: modulus value (NLA_U32)
  * @NFTA_HASH_SEED: seed value (NLA_U32)
+ * @NFTA_HASH_OFFSET: add this offset value to hash result (NLA_U32)
  */
 enum nft_hash_attributes {
         NFTA_HASH_UNSPEC,
@@ -739,6 +740,7 @@ enum nft_hash_attributes {
         NFTA_HASH_LEN,
         NFTA_HASH_MODULUS,
         NFTA_HASH_SEED,
+        NFTA_HASH_OFFSET,
         __NFTA_HASH_MAX,
 };
 #define NFTA_HASH_MAX   (__NFTA_HASH_MAX - 1)