1 files changed, 304 insertions, 0 deletions
diff --git a/net/netfilter/nft_quota.c b/net/netfilter/nft_quota.c
new file mode 100644
index 000000000..410a5fcf8
--- /dev/null
+++ b/net/netfilter/nft_quota.c
@@ -0,0 +1,304 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/atomic.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables.h>
+
+struct nft_quota {
+	atomic64_t	quota;
+	unsigned long	flags;
+	atomic64_t	*consumed;
+};
+
+static inline bool nft_overquota(struct nft_quota *priv,
+				 const struct sk_buff *skb)
+{
+	return atomic64_add_return(skb->len, priv->consumed) >=
+	       atomic64_read(&priv->quota);
+}
+
+static inline bool nft_quota_invert(struct nft_quota *priv)
+{
+	return priv->flags & NFT_QUOTA_F_INV;
+}
+
+static inline void nft_quota_do_eval(struct nft_quota *priv,
+				     struct nft_regs *regs,
+				     const struct nft_pktinfo *pkt)
+{
+	if (nft_overquota(priv, pkt->skb) ^ nft_quota_invert(priv))
+		regs->verdict.code = NFT_BREAK;
+}
+
+static const struct nla_policy nft_quota_policy[NFTA_QUOTA_MAX + 1] = {
+	[NFTA_QUOTA_BYTES]	= { .type = NLA_U64 },
+	[NFTA_QUOTA_FLAGS]	= { .type = NLA_U32 },
+	[NFTA_QUOTA_CONSUMED]	= { .type = NLA_U64 },
+};
+
+#define NFT_QUOTA_DEPLETED_BIT	1	/* From NFT_QUOTA_F_DEPLETED. */
+
+static void nft_quota_obj_eval(struct nft_object *obj,
+			       struct nft_regs *regs,
+			       const struct nft_pktinfo *pkt)
+{
+	struct nft_quota *priv = nft_obj_data(obj);
+	bool overquota;
+
+	overquota = nft_overquota(priv, pkt->skb);
+	if (overquota ^ nft_quota_invert(priv))
+		regs->verdict.code = NFT_BREAK;
+
+	if (overquota &&
+	    !test_and_set_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags))
+		nft_obj_notify(nft_net(pkt), obj->key.table, obj, 0, 0,
+			       NFT_MSG_NEWOBJ, 0, nft_pf(pkt), 0, GFP_ATOMIC);
+}
+
+static int nft_quota_do_init(const struct nlattr * const tb[],
+			     struct nft_quota *priv)
+{
+	unsigned long flags = 0;
+	u64 quota, consumed = 0;
+
+	if (!tb[NFTA_QUOTA_BYTES])
+		return -EINVAL;
+
+	quota = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_BYTES]));
+	if (quota > S64_MAX)
+		return -EOVERFLOW;
+
+	if (tb[NFTA_QUOTA_CONSUMED]) {
+		consumed = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_CONSUMED]));
+		if (consumed > quota)
+			return -EINVAL;
+	}
+
+	if (tb[NFTA_QUOTA_FLAGS]) {
+		flags = ntohl(nla_get_be32(tb[NFTA_QUOTA_FLAGS]));
+		if (flags & ~NFT_QUOTA_F_INV)
+			return -EINVAL;
+		if (flags & NFT_QUOTA_F_DEPLETED)
+			return -EOPNOTSUPP;
+	}
+
+	priv->consumed = kmalloc(sizeof(*priv->consumed), GFP_KERNEL_ACCOUNT);
+	if (!priv->consumed)
+		return -ENOMEM;
+
+	atomic64_set(&priv->quota, quota);
+	priv->flags = flags;
+	atomic64_set(priv->consumed, consumed);
+
+	return 0;
+}
+
+static void nft_quota_do_destroy(const struct nft_ctx *ctx,
+				 struct nft_quota *priv)
+{
+	kfree(priv->consumed);
+}
+
+static int nft_quota_obj_init(const struct nft_ctx *ctx,
+			      const struct nlattr * const tb[],
+			      struct nft_object *obj)
+{
+	struct nft_quota *priv = nft_obj_data(obj);
+
+	return nft_quota_do_init(tb, priv);
+}
+
+static void nft_quota_obj_update(struct nft_object *obj,
+				 struct nft_object *newobj)
+{
+	struct nft_quota *newpriv = nft_obj_data(newobj);
+	struct nft_quota *priv = nft_obj_data(obj);
+	u64 newquota;
+
+	newquota = atomic64_read(&newpriv->quota);
+	atomic64_set(&priv->quota, newquota);
+	priv->flags = newpriv->flags;
+}
+
+static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv,
+			     bool reset)
+{
+	u64 consumed, consumed_cap, quota;
+	u32 flags = priv->flags;
+
+	/* Since we inconditionally increment consumed quota for each packet
+	 * that we see, don't go over the quota boundary in what we send to
+	 * userspace.
+	 */
+	consumed = atomic64_read(priv->consumed);
+	quota = atomic64_read(&priv->quota);
+	if (consumed >= quota) {
+		consumed_cap = quota;
+		flags |= NFT_QUOTA_F_DEPLETED;
+	} else {
+		consumed_cap = consumed;
+	}
+
+	if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(quota),
+			 NFTA_QUOTA_PAD) ||
+	    nla_put_be64(skb, NFTA_QUOTA_CONSUMED, cpu_to_be64(consumed_cap),
+			 NFTA_QUOTA_PAD) ||
+	    nla_put_be32(skb, NFTA_QUOTA_FLAGS, htonl(flags)))
+		goto nla_put_failure;
+
+	if (reset) {
+		atomic64_sub(consumed, priv->consumed);
+		clear_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags);
+	}
+	return 0;
+
+nla_put_failure:
+	return -1;
+}
+
+static int nft_quota_obj_dump(struct sk_buff *skb, struct nft_object *obj,
+			      bool reset)
+{
+	struct nft_quota *priv = nft_obj_data(obj);
+
+	return nft_quota_do_dump(skb, priv, reset);
+}
+
+static void nft_quota_obj_destroy(const struct nft_ctx *ctx,
+				  struct nft_object *obj)
+{
+	struct nft_quota *priv = nft_obj_data(obj);
+
+	return nft_quota_do_destroy(ctx, priv);
+}
+
+static struct nft_object_type nft_quota_obj_type;
+static const struct nft_object_ops nft_quota_obj_ops = {
+	.type		= &nft_quota_obj_type,
+	.size		= sizeof(struct nft_quota),
+	.init		= nft_quota_obj_init,
+	.destroy	= nft_quota_obj_destroy,
+	.eval		= nft_quota_obj_eval,
+	.dump		= nft_quota_obj_dump,
+	.update		= nft_quota_obj_update,
+};
+
+static struct nft_object_type nft_quota_obj_type __read_mostly = {
+	.type		= NFT_OBJECT_QUOTA,
+	.ops		= &nft_quota_obj_ops,
+	.maxattr	= NFTA_QUOTA_MAX,
+	.policy		= nft_quota_policy,
+	.owner		= THIS_MODULE,
+};
+
+static void nft_quota_eval(const struct nft_expr *expr,
+			   struct nft_regs *regs,
+			   const struct nft_pktinfo *pkt)
+{
+	struct nft_quota *priv = nft_expr_priv(expr);
+
+	nft_quota_do_eval(priv, regs, pkt);
+}
+
+static int nft_quota_init(const struct nft_ctx *ctx,
+			  const struct nft_expr *expr,
+			  const struct nlattr * const tb[])
+{
+	struct nft_quota *priv = nft_expr_priv(expr);
+
+	return nft_quota_do_init(tb, priv);
+}
+
+static int nft_quota_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+	struct nft_quota *priv = nft_expr_priv(expr);
+
+	return nft_quota_do_dump(skb, priv, false);
+}
+
+static void nft_quota_destroy(const struct nft_ctx *ctx,
+			      const struct nft_expr *expr)
+{
+	struct nft_quota *priv = nft_expr_priv(expr);
+
+	return nft_quota_do_destroy(ctx, priv);
+}
+
+static int nft_quota_clone(struct nft_expr *dst, const struct nft_expr *src)
+{
+	struct nft_quota *priv_dst = nft_expr_priv(dst);
+	struct nft_quota *priv_src = nft_expr_priv(src);
+
+	priv_dst->quota = priv_src->quota;
+	priv_dst->flags = priv_src->flags;
+
+	priv_dst->consumed = kmalloc(sizeof(*priv_dst->consumed), GFP_ATOMIC);
+	if (!priv_dst->consumed)
+		return -ENOMEM;
+
+	*priv_dst->consumed = *priv_src->consumed;
+
+	return 0;
+}
+
+static struct nft_expr_type nft_quota_type;
+static const struct nft_expr_ops nft_quota_ops = {
+	.type		= &nft_quota_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_quota)),
+	.eval		= nft_quota_eval,
+	.init		= nft_quota_init,
+	.destroy	= nft_quota_destroy,
+	.clone		= nft_quota_clone,
+	.dump		= nft_quota_dump,
+	.reduce		= NFT_REDUCE_READONLY,
+};
+
+static struct nft_expr_type nft_quota_type __read_mostly = {
+	.name		= "quota",
+	.ops		= &nft_quota_ops,
+	.policy		= nft_quota_policy,
+	.maxattr	= NFTA_QUOTA_MAX,
+	.flags		= NFT_EXPR_STATEFUL,
+	.owner		= THIS_MODULE,
+};
+
+static int __init nft_quota_module_init(void)
+{
+	int err;
+
+	err = nft_register_obj(&nft_quota_obj_type);
+	if (err < 0)
+		return err;
+
+	err = nft_register_expr(&nft_quota_type);
+	if (err < 0)
+		goto err1;
+
+	return 0;
+err1:
+	nft_unregister_obj(&nft_quota_obj_type);
+	return err;
+}
+
+static void __exit nft_quota_module_exit(void)
+{
+	nft_unregister_expr(&nft_quota_type);
+	nft_unregister_obj(&nft_quota_obj_type);
+}
+
+module_init(nft_quota_module_init);
+module_exit(nft_quota_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
+MODULE_ALIAS_NFT_EXPR("quota");
+MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_QUOTA);
+MODULE_DESCRIPTION("Netfilter nftables quota module");