netfilter: nf_tables: Expose the table usage counter via netlink

Userspace can therefore know whether a table is in use or not, and
by how many chains. Suggested by Pablo Neira Ayuso.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

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 256d36b1b94a..b25481e16f0a 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -110,11 +110,13 @@ enum nft_table_flags {
  *
  * @NFTA_TABLE_NAME: name of the table (NLA_STRING)
  * @NFTA_TABLE_FLAGS: bitmask of enum nft_table_flags (NLA_U32)
+ * @NFTA_TABLE_USE: number of chains in this table (NLA_U32)
  */
 enum nft_table_attributes {
         NFTA_TABLE_UNSPEC,
         NFTA_TABLE_NAME,
         NFTA_TABLE_FLAGS,
+        NFTA_TABLE_USE,
         __NFTA_TABLE_MAX
 };
 #define NFTA_TABLE_MAX          (__NFTA_TABLE_MAX - 1)