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Commit 976afca1 authored by Yi-Hung Wei's avatar Yi-Hung Wei Committed by Pablo Neira Ayuso
Browse files

netfilter: nf_conncount: Early exit in nf_conncount_lookup() and cleanup 



This patch is originally from Florian Westphal.

This patch does the following three tasks.

It applies the same early exit technique for nf_conncount_lookup().

Since now we keep the number of connections in 'struct nf_conncount_list',
we no longer need to return the count in nf_conncount_lookup().

Moreover, we expose the garbage collection function nf_conncount_gc_list()
for nft_connlimit.

Signed-off-by: default avatarYi-Hung Wei <yihung.wei@gmail.com>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent cb2b36f5

include/net/netfilter/nf_conntrack_count.h

+7 −4
Original line number Diff line number Diff line
@@ -21,7 +21,7 @@ unsigned int nf_conncount_count(struct net *net, 
				const struct nf_conntrack_tuple *tuple,

				const struct nf_conntrack_zone *zone);



unsigned int nf_conncount_lookup(struct net *net, struct nf_conncount_list *list,

void nf_conncount_lookup(struct net *net, struct nf_conncount_list *list,

			 const struct nf_conntrack_tuple *tuple,

			 const struct nf_conntrack_zone *zone,

			 bool *addit);
@@ -32,6 +32,9 @@ bool nf_conncount_add(struct nf_conncount_list *list, 
		      const struct nf_conntrack_tuple *tuple,

		      const struct nf_conntrack_zone *zone);



void nf_conncount_gc_list(struct net *net,

			  struct nf_conncount_list *list);



void nf_conncount_cache_free(struct nf_conncount_list *list);



#endif

net/netfilter/nf_conncount.c

+21 −17
Original line number Diff line number Diff line
@@ -144,7 +144,7 @@ find_or_evict(struct net *net, struct nf_conncount_list *list, 
	return ERR_PTR(-EAGAIN);

}



unsigned int nf_conncount_lookup(struct net *net,

void nf_conncount_lookup(struct net *net,

			 struct nf_conncount_list *list,

			 const struct nf_conntrack_tuple *tuple,

			 const struct nf_conntrack_zone *zone,
@@ -153,17 +153,20 @@ unsigned int nf_conncount_lookup(struct net *net, 
	const struct nf_conntrack_tuple_hash *found;

	struct nf_conncount_tuple *conn, *conn_n;

	struct nf_conn *found_ct;

	unsigned int length = 0;

	unsigned int collect = 0;



	/* best effort only */

	*addit = tuple ? true : false;



	/* check the saved connections */

	list_for_each_entry_safe(conn, conn_n, &list->head, node) {

		if (collect > CONNCOUNT_GC_MAX_NODES)

			break;



		found = find_or_evict(net, list, conn);

		if (IS_ERR(found)) {

			/* Not found, but might be about to be confirmed */

			if (PTR_ERR(found) == -EAGAIN) {

				length++;

				if (!tuple)

					continue;
@@ -171,8 +174,8 @@ unsigned int nf_conncount_lookup(struct net *net, 
				    nf_ct_zone_id(&conn->zone, conn->zone.dir) ==

				    nf_ct_zone_id(zone, zone->dir))

					*addit = false;

			}



			} else if (PTR_ERR(found) == -ENOENT)

				collect++;

			continue;

		}
@@ -181,9 +184,10 @@ unsigned int nf_conncount_lookup(struct net *net, 
		if (tuple && nf_ct_tuple_equal(&conn->tuple, tuple) &&

		    nf_ct_zone_equal(found_ct, zone, zone->dir)) {

			/*

			 * Just to be sure we have it only once in the list.

			 * We should not see tuples twice unless someone hooks

			 * this into a table without "-p tcp --syn".

			 *

			 * Attempt to avoid a re-add in this case.

			 */

			*addit = false;

		} else if (already_closed(found_ct)) {
@@ -193,14 +197,12 @@ unsigned int nf_conncount_lookup(struct net *net, 
			 */

			nf_ct_put(found_ct);

			conn_free(list, conn);

			collect++;

			continue;

		}



		nf_ct_put(found_ct);

		length++;

	}



	return length;

}

EXPORT_SYMBOL_GPL(nf_conncount_lookup);
@@ -211,7 +213,7 @@ void nf_conncount_list_init(struct nf_conncount_list *list) 
}

EXPORT_SYMBOL_GPL(nf_conncount_list_init);



static void nf_conncount_gc_list(struct net *net,

void nf_conncount_gc_list(struct net *net,

			  struct nf_conncount_list *list)

{

	const struct nf_conntrack_tuple_hash *found;
@@ -244,6 +246,7 @@ static void nf_conncount_gc_list(struct net *net, 
			return;

	}

}

EXPORT_SYMBOL_GPL(nf_conncount_gc_list);



static void tree_nodes_free(struct rb_root *root,

			    struct nf_conncount_rb *gc_nodes[],
@@ -291,8 +294,9 @@ count_tree(struct net *net, struct rb_root *root, 
			/* same source network -> be counted! */

			unsigned int count;



			count = nf_conncount_lookup(net, &rbconn->list, tuple,

						    zone, &addit);

			nf_conncount_lookup(net, &rbconn->list, tuple, zone,

					    &addit);

			count = rbconn->list.count;



			tree_nodes_free(root, gc_nodes, gc_count);

			if (!addit)

net/netfilter/nft_connlimit.c

+5 −4
Original line number Diff line number Diff line
@@ -46,8 +46,9 @@ static inline void nft_connlimit_do_eval(struct nft_connlimit *priv, 
	}



	spin_lock_bh(&priv->lock);

	count = nf_conncount_lookup(nft_net(pkt), &priv->list, tuple_ptr, zone,

	nf_conncount_lookup(nft_net(pkt), &priv->list, tuple_ptr, zone,

			    &addit);

	count = priv->list.count;



	if (!addit)

		goto out;
@@ -231,10 +232,10 @@ static void nft_connlimit_destroy_clone(const struct nft_ctx *ctx, 
static bool nft_connlimit_gc(struct net *net, const struct nft_expr *expr)

{

	struct nft_connlimit *priv = nft_expr_priv(expr);

	bool addit, ret;

	bool ret;



	spin_lock_bh(&priv->lock);

	nf_conncount_lookup(net, &priv->list, NULL, &nf_ct_zone_dflt, &addit);

	nf_conncount_gc_list(net, &priv->list);



	ret = list_empty(&priv->list.head);

	spin_unlock_bh(&priv->lock);