1 files changed, 119 insertions, 0 deletions
diff --git a/net/netfilter/nft_limit.c b/net/netfilter/nft_limit.c
new file mode 100644
index 00000000000..85da5bd02f6
--- /dev/null
+++ b/net/netfilter/nft_limit.c
@@ -0,0 +1,119 @@
+/*
+ * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Development of this code funded by Astaro AG (http://www.astaro.com/)
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables.h>
+
+static DEFINE_SPINLOCK(limit_lock);
+
+struct nft_limit {
+	u64		tokens;
+	u64		rate;
+	u64		unit;
+	unsigned long	stamp;
+};
+
+static void nft_limit_eval(const struct nft_expr *expr,
+			   struct nft_data data[NFT_REG_MAX + 1],
+			   const struct nft_pktinfo *pkt)
+{
+	struct nft_limit *priv = nft_expr_priv(expr);
+
+	spin_lock_bh(&limit_lock);
+	if (time_after_eq(jiffies, priv->stamp)) {
+		priv->tokens = priv->rate;
+		priv->stamp = jiffies + priv->unit * HZ;
+	}
+
+	if (priv->tokens >= 1) {
+		priv->tokens--;
+		spin_unlock_bh(&limit_lock);
+		return;
+	}
+	spin_unlock_bh(&limit_lock);
+
+	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
+}
+
+static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = {
+	[NFTA_LIMIT_RATE]	= { .type = NLA_U64 },
+	[NFTA_LIMIT_UNIT]	= { .type = NLA_U64 },
+};
+
+static int nft_limit_init(const struct nft_ctx *ctx,
+			  const struct nft_expr *expr,
+			  const struct nlattr * const tb[])
+{
+	struct nft_limit *priv = nft_expr_priv(expr);
+
+	if (tb[NFTA_LIMIT_RATE] == NULL ||
+	    tb[NFTA_LIMIT_UNIT] == NULL)
+		return -EINVAL;
+
+	priv->rate   = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE]));
+	priv->unit   = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT]));
+	priv->stamp  = jiffies + priv->unit * HZ;
+	priv->tokens = priv->rate;
+	return 0;
+}
+
+static int nft_limit_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+	const struct nft_limit *priv = nft_expr_priv(expr);
+
+	if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(priv->rate)))
+		goto nla_put_failure;
+	if (nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(priv->unit)))
+		goto nla_put_failure;
+	return 0;
+
+nla_put_failure:
+	return -1;
+}
+
+static struct nft_expr_type nft_limit_type;
+static const struct nft_expr_ops nft_limit_ops = {
+	.type		= &nft_limit_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_limit)),
+	.eval		= nft_limit_eval,
+	.init		= nft_limit_init,
+	.dump		= nft_limit_dump,
+};
+
+static struct nft_expr_type nft_limit_type __read_mostly = {
+	.name		= "limit",
+	.ops		= &nft_limit_ops,
+	.policy		= nft_limit_policy,
+	.maxattr	= NFTA_LIMIT_MAX,
+	.owner		= THIS_MODULE,
+};
+
+static int __init nft_limit_module_init(void)
+{
+	return nft_register_expr(&nft_limit_type);
+}
+
+static void __exit nft_limit_module_exit(void)
+{
+	nft_unregister_expr(&nft_limit_type);
+}
+
+module_init(nft_limit_module_init);
+module_exit(nft_limit_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_ALIAS_NFT_EXPR("limit");