[PATCH nf-next 4/5] netfilter: nf_tables: add check_genid to the nfnetlink subsystem

[Pablo Neira Ayuso <pablo@netfilter.org>]

This patch implements the check generation id as provided by nfnetlink.
This allows us to reject ruleset updates against stale baseline, so
userspace can retry update with a fresh ruleset cache.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_tables_api.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index cb6ae46f6c48..71c60a04b66b 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4972,6 +4972,11 @@ static int nf_tables_abort(struct net *net, struct sk_buff *skb)
 	return 0;
 }
 
+static bool nf_tables_valid_genid(struct net *net, u32 genid)
+{
+	return net->nft.base_seq == genid;
+}
+
 static const struct nfnetlink_subsystem nf_tables_subsys = {
 	.name		= "nf_tables",
 	.subsys_id	= NFNL_SUBSYS_NFTABLES,
@@ -4979,6 +4984,7 @@ static const struct nfnetlink_subsystem nf_tables_subsys = {
 	.cb		= nf_tables_cb,
 	.commit		= nf_tables_commit,
 	.abort		= nf_tables_abort,
+	.valid_genid	= nf_tables_valid_genid,
 };
 
 int nft_chain_validate_dependency(const struct nft_chain *chain,
-- 
2.1.4