netfilter: nf_conncount: Switch to plain list

Original patch is from Florian Westphal.

This patch switches from hlist to plain list to store the list of
connections with the same filtering key in nf_conncount. With the
plain list, we can insert new connections at the tail, so over time
the beginning of list holds long-running connections and those are
expired, while the newly creates ones are at the end.

Later on, we could probably move checked ones to the end of the list,
so the next run has higher chance to reclaim stale entries in the front.

Signed-off-by: Yi-Hung Wei <yihung.wei@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 12 insertions, 12 deletions

diff --git a/net/netfilter/nft_connlimit.c b/net/netfilter/nft_connlimit.c
index a832c59f0a9c..4f0491a36a1d 100644
--- a/net/netfilter/nft_connlimit.c
+++ b/net/netfilter/nft_connlimit.c
@@ -14,10 +14,10 @@
 #include <net/netfilter/nf_conntrack_zones.h>
 
 struct nft_connlimit {
-	spinlock_t		lock;
-	struct hlist_head	hhead;
-	u32			limit;
-	bool			invert;
+	spinlock_t			lock;
+	struct nf_conncount_list	list;
+	u32				limit;
+	bool				invert;
 };
 
 static inline void nft_connlimit_do_eval(struct nft_connlimit *priv,
@@ -46,13 +46,13 @@ static inline void nft_connlimit_do_eval(struct nft_connlimit *priv,
 	}
 
 	spin_lock_bh(&priv->lock);
-	count = nf_conncount_lookup(nft_net(pkt), &priv->hhead, tuple_ptr, zone,
+	count = nf_conncount_lookup(nft_net(pkt), &priv->list, tuple_ptr, zone,
 				    &addit);
 
 	if (!addit)
 		goto out;
 
-	if (!nf_conncount_add(&priv->hhead, tuple_ptr, zone)) {
+	if (!nf_conncount_add(&priv->list, tuple_ptr, zone)) {
 		regs->verdict.code = NF_DROP;
 		spin_unlock_bh(&priv->lock);
 		return;
@@ -88,7 +88,7 @@ static int nft_connlimit_do_init(const struct nft_ctx *ctx,
 	}
 
 	spin_lock_init(&priv->lock);
-	INIT_HLIST_HEAD(&priv->hhead);
+	nf_conncount_list_init(&priv->list);
 	priv->limit	= limit;
 	priv->invert	= invert;
 
@@ -99,7 +99,7 @@ static void nft_connlimit_do_destroy(const struct nft_ctx *ctx,
 				     struct nft_connlimit *priv)
 {
 	nf_ct_netns_put(ctx->net, ctx->family);
-	nf_conncount_cache_free(&priv->hhead);
+	nf_conncount_cache_free(&priv->list);
 }
 
 static int nft_connlimit_do_dump(struct sk_buff *skb,
@@ -213,7 +213,7 @@ static int nft_connlimit_clone(struct nft_expr *dst, const struct nft_expr *src)
 	struct nft_connlimit *priv_src = nft_expr_priv(src);
 
 	spin_lock_init(&priv_dst->lock);
-	INIT_HLIST_HEAD(&priv_dst->hhead);
+	nf_conncount_list_init(&priv_dst->list);
 	priv_dst->limit	 = priv_src->limit;
 	priv_dst->invert = priv_src->invert;
 
@@ -225,7 +225,7 @@ static void nft_connlimit_destroy_clone(const struct nft_ctx *ctx,
 {
 	struct nft_connlimit *priv = nft_expr_priv(expr);
 
-	nf_conncount_cache_free(&priv->hhead);
+	nf_conncount_cache_free(&priv->list);
 }
 
 static bool nft_connlimit_gc(struct net *net, const struct nft_expr *expr)
@@ -234,9 +234,9 @@ static bool nft_connlimit_gc(struct net *net, const struct nft_expr *expr)
 	bool addit, ret;
 
 	spin_lock_bh(&priv->lock);
-	nf_conncount_lookup(net, &priv->hhead, NULL, &nf_ct_zone_dflt, &addit);
+	nf_conncount_lookup(net, &priv->list, NULL, &nf_ct_zone_dflt, &addit);
 
-	ret = hlist_empty(&priv->hhead);
+	ret = list_empty(&priv->list.head);
 	spin_unlock_bh(&priv->lock);
 
 	return ret;