User space 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@xxxxxxxxxxxxxxx>
---
include/uapi/linux/netfilter/nf_tables.h | 2 ++
net/netfilter/nf_tables_api.c | 3 ++-
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index b108548..28f0ffb 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_CHAINS: number of chains in this table (NLA_U32)
*/
enum nft_table_attributes {
NFTA_TABLE_UNSPEC,
NFTA_TABLE_NAME,
NFTA_TABLE_FLAGS,
+ NFTA_TABLE_CHAINS,
__NFTA_TABLE_MAX
};
#define NFTA_TABLE_MAX (__NFTA_TABLE_MAX - 1)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index dcddc49..482b689 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -180,7 +180,8 @@ static int nf_tables_fill_table_info(struct sk_buff *skb, u32 portid, u32 seq,
nfmsg->res_id = 0;
if (nla_put_string(skb, NFTA_TABLE_NAME, table->name) ||
- nla_put_be32(skb, NFTA_TABLE_FLAGS, htonl(table->flags)))
+ nla_put_be32(skb, NFTA_TABLE_FLAGS, htonl(table->flags)) ||
+ nla_put_be32(skb, NFTA_TABLE_CHAINS, htonl(table->use)))
goto nla_put_failure;
return nlmsg_end(skb, nlh);
--
1.8.3.2
--
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