[PATCH 6.1 1/2] netfilter: nf_tables: allow to create netdev chain without device

[Ma Xinmeng]

From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>

Relax netdev chain creation to allow for loading the ruleset, then
adding/deleting devices at a later stage. Hardware offload does not
support for this feature yet.

Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Ma Xinmeng <1564938642@xxxxxx>

This is a 6.1 backport of upstream commit 207296f1a03b; the hunk for
nft_delchain_hook() is dropped since that function is not present in 6.1.
---
 net/netfilter/nf_tables_api.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 96b0638c2..18aa388d5 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2180,7 +2180,7 @@ struct nft_chain_hook {
 
 static int nft_chain_parse_netdev(struct net *net,
 				  struct nlattr *tb[],
-				  struct list_head *hook_list)
+				  struct list_head *hook_list, u32 flags)
 {
 	struct nft_hook *hook;
 	int err;
@@ -2197,19 +2197,20 @@ static int nft_chain_parse_netdev(struct net *net,
 		if (err < 0)
 			return err;
 
-		if (list_empty(hook_list))
-			return -EINVAL;
-	} else {
-		return -EINVAL;
 	}
 
+	if (flags & NFT_CHAIN_HW_OFFLOAD &&
+	    list_empty(hook_list))
+		return -EINVAL;
+
 	return 0;
 }
 
 static int nft_chain_parse_hook(struct net *net,
 				const struct nlattr * const nla[],
 				struct nft_chain_hook *hook, u8 family,
-				struct netlink_ext_ack *extack, bool autoload)
+				struct netlink_ext_ack *extack, bool autoload,
+				u32 flags)
 {
 	struct nftables_pernet *nft_net = nft_pernet(net);
 	struct nlattr *ha[NFTA_HOOK_MAX + 1];
@@ -2261,7 +2262,7 @@ static int nft_chain_parse_hook(struct net *net,
 
 	INIT_LIST_HEAD(&hook->list);
 	if (nft_base_chain_netdev(family, hook->num)) {
-		err = nft_chain_parse_netdev(net, ha, &hook->list);
+		err = nft_chain_parse_netdev(net, ha, &hook->list, flags);
 		if (err < 0) {
 			module_put(type->owner);
 			return err;
@@ -2409,7 +2410,7 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
 			return -EOPNOTSUPP;
 
 		err = nft_chain_parse_hook(net, nla, &hook, family, extack,
-					   true);
+					   true, flags);
 		if (err < 0)
 			return err;
 
@@ -2574,7 +2575,7 @@ static int nf_tables_updchain(struct nft_ctx *ctx, u8 genmask, u8 policy,
 			return -EEXIST;
 		}
 		err = nft_chain_parse_hook(ctx->net, nla, &hook, ctx->family,
-					   extack, false);
+					   extack, false, flags);
 		if (err < 0)
 			return err;
 
@@ -2795,6 +2796,7 @@ static int nf_tables_newchain(struct sk_buff *skb, const struct nfnl_info *info,
 	return nf_tables_addchain(&ctx, family, genmask, policy, flags, extack);
 }
 
+
 static int nf_tables_delchain(struct sk_buff *skb, const struct nfnl_info *info,
 			      const struct nlattr * const nla[])
 {
-- 
2.43.0