1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
  4 */
  5
  6#include <linux/kernel.h>
  7#include <linux/init.h>
  8#include <linux/module.h>
  9#include <linux/atomic.h>
 10#include <linux/netlink.h>
 11#include <linux/netfilter.h>
 12#include <linux/netfilter/nf_tables.h>
 13#include <net/netfilter/nf_tables.h>
 14
 15struct nft_quota {
 16	atomic64_t	quota;
 17	unsigned long	flags;
 18	atomic64_t	consumed;
 19};
 20
 21static inline bool nft_overquota(struct nft_quota *priv,
 22				 const struct sk_buff *skb)
 23{
 24	return atomic64_add_return(skb->len, &priv->consumed) >=
 25	       atomic64_read(&priv->quota);
 26}
 27
 28static inline bool nft_quota_invert(struct nft_quota *priv)
 29{
 30	return priv->flags & NFT_QUOTA_F_INV;
 31}
 32
 33static inline void nft_quota_do_eval(struct nft_quota *priv,
 34				     struct nft_regs *regs,
 35				     const struct nft_pktinfo *pkt)
 36{
 37	if (nft_overquota(priv, pkt->skb) ^ nft_quota_invert(priv))
 38		regs->verdict.code = NFT_BREAK;
 39}
 40
 41static const struct nla_policy nft_quota_policy[NFTA_QUOTA_MAX + 1] = {
 42	[NFTA_QUOTA_BYTES]	= { .type = NLA_U64 },
 43	[NFTA_QUOTA_FLAGS]	= { .type = NLA_U32 },
 44	[NFTA_QUOTA_CONSUMED]	= { .type = NLA_U64 },
 45};
 46
 47#define NFT_QUOTA_DEPLETED_BIT	1	/* From NFT_QUOTA_F_DEPLETED. */
 48
 49static void nft_quota_obj_eval(struct nft_object *obj,
 50			       struct nft_regs *regs,
 51			       const struct nft_pktinfo *pkt)
 52{
 53	struct nft_quota *priv = nft_obj_data(obj);
 54	bool overquota;
 55
 56	overquota = nft_overquota(priv, pkt->skb);
 57	if (overquota ^ nft_quota_invert(priv))
 58		regs->verdict.code = NFT_BREAK;
 59
 60	if (overquota &&
 61	    !test_and_set_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags))
 62		nft_obj_notify(nft_net(pkt), obj->key.table, obj, 0, 0,
 63			       NFT_MSG_NEWOBJ, 0, nft_pf(pkt), 0, GFP_ATOMIC);
 64}
 65
 66static int nft_quota_do_init(const struct nlattr * const tb[],
 67			     struct nft_quota *priv)
 68{
 69	unsigned long flags = 0;
 70	u64 quota, consumed = 0;
 71
 72	if (!tb[NFTA_QUOTA_BYTES])
 73		return -EINVAL;
 74
 75	quota = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_BYTES]));
 76	if (quota > S64_MAX)
 77		return -EOVERFLOW;
 78
 79	if (tb[NFTA_QUOTA_CONSUMED]) {
 80		consumed = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_CONSUMED]));
 81		if (consumed > quota)
 82			return -EINVAL;
 83	}
 84
 85	if (tb[NFTA_QUOTA_FLAGS]) {
 86		flags = ntohl(nla_get_be32(tb[NFTA_QUOTA_FLAGS]));
 87		if (flags & ~NFT_QUOTA_F_INV)
 88			return -EINVAL;
 89		if (flags & NFT_QUOTA_F_DEPLETED)
 90			return -EOPNOTSUPP;
 91	}
 92
 93	atomic64_set(&priv->quota, quota);
 94	priv->flags = flags;
 95	atomic64_set(&priv->consumed, consumed);
 96
 97	return 0;
 98}
 99
100static int nft_quota_obj_init(const struct nft_ctx *ctx,
101			      const struct nlattr * const tb[],
102			      struct nft_object *obj)
103{
104	struct nft_quota *priv = nft_obj_data(obj);
105
106	return nft_quota_do_init(tb, priv);
107}
108
109static void nft_quota_obj_update(struct nft_object *obj,
110				 struct nft_object *newobj)
111{
112	struct nft_quota *newpriv = nft_obj_data(newobj);
113	struct nft_quota *priv = nft_obj_data(obj);
114	u64 newquota;
115
116	newquota = atomic64_read(&newpriv->quota);
117	atomic64_set(&priv->quota, newquota);
118	priv->flags = newpriv->flags;
119}
120
121static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv,
122			     bool reset)
123{
124	u64 consumed, consumed_cap, quota;
125	u32 flags = priv->flags;
126
127	/* Since we inconditionally increment consumed quota for each packet
128	 * that we see, don't go over the quota boundary in what we send to
129	 * userspace.
130	 */
131	consumed = atomic64_read(&priv->consumed);
132	quota = atomic64_read(&priv->quota);
133	if (consumed >= quota) {
134		consumed_cap = quota;
135		flags |= NFT_QUOTA_F_DEPLETED;
136	} else {
137		consumed_cap = consumed;
138	}
139
140	if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(quota),
141			 NFTA_QUOTA_PAD) ||
142	    nla_put_be64(skb, NFTA_QUOTA_CONSUMED, cpu_to_be64(consumed_cap),
143			 NFTA_QUOTA_PAD) ||
144	    nla_put_be32(skb, NFTA_QUOTA_FLAGS, htonl(flags)))
145		goto nla_put_failure;
146
147	if (reset) {
148		atomic64_sub(consumed, &priv->consumed);
149		clear_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags);
150	}
151	return 0;
152
153nla_put_failure:
154	return -1;
155}
156
157static int nft_quota_obj_dump(struct sk_buff *skb, struct nft_object *obj,
158			      bool reset)
159{
160	struct nft_quota *priv = nft_obj_data(obj);
161
162	return nft_quota_do_dump(skb, priv, reset);
163}
164
165static struct nft_object_type nft_quota_obj_type;
166static const struct nft_object_ops nft_quota_obj_ops = {
167	.type		= &nft_quota_obj_type,
168	.size		= sizeof(struct nft_quota),
169	.init		= nft_quota_obj_init,
170	.eval		= nft_quota_obj_eval,
171	.dump		= nft_quota_obj_dump,
172	.update		= nft_quota_obj_update,
173};
174
175static struct nft_object_type nft_quota_obj_type __read_mostly = {
176	.type		= NFT_OBJECT_QUOTA,
177	.ops		= &nft_quota_obj_ops,
178	.maxattr	= NFTA_QUOTA_MAX,
179	.policy		= nft_quota_policy,
180	.owner		= THIS_MODULE,
181};
182
183static void nft_quota_eval(const struct nft_expr *expr,
184			   struct nft_regs *regs,
185			   const struct nft_pktinfo *pkt)
186{
187	struct nft_quota *priv = nft_expr_priv(expr);
188
189	nft_quota_do_eval(priv, regs, pkt);
190}
191
192static int nft_quota_init(const struct nft_ctx *ctx,
193			  const struct nft_expr *expr,
194			  const struct nlattr * const tb[])
195{
196	struct nft_quota *priv = nft_expr_priv(expr);
197
198	return nft_quota_do_init(tb, priv);
199}
200
201static int nft_quota_dump(struct sk_buff *skb, const struct nft_expr *expr)
202{
203	struct nft_quota *priv = nft_expr_priv(expr);
204
205	return nft_quota_do_dump(skb, priv, false);
206}
207
208static struct nft_expr_type nft_quota_type;
209static const struct nft_expr_ops nft_quota_ops = {
210	.type		= &nft_quota_type,
211	.size		= NFT_EXPR_SIZE(sizeof(struct nft_quota)),
212	.eval		= nft_quota_eval,
213	.init		= nft_quota_init,
214	.dump		= nft_quota_dump,
215};
216
217static struct nft_expr_type nft_quota_type __read_mostly = {
218	.name		= "quota",
219	.ops		= &nft_quota_ops,
220	.policy		= nft_quota_policy,
221	.maxattr	= NFTA_QUOTA_MAX,
222	.flags		= NFT_EXPR_STATEFUL,
223	.owner		= THIS_MODULE,
224};
225
226static int __init nft_quota_module_init(void)
227{
228	int err;
229
230	err = nft_register_obj(&nft_quota_obj_type);
231	if (err < 0)
232		return err;
233
234	err = nft_register_expr(&nft_quota_type);
235	if (err < 0)
236		goto err1;
237
238	return 0;
239err1:
240	nft_unregister_obj(&nft_quota_obj_type);
241	return err;
242}
243
244static void __exit nft_quota_module_exit(void)
245{
246	nft_unregister_expr(&nft_quota_type);
247	nft_unregister_obj(&nft_quota_obj_type);
248}
249
250module_init(nft_quota_module_init);
251module_exit(nft_quota_module_exit);
252
253MODULE_LICENSE("GPL");
254MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
255MODULE_ALIAS_NFT_EXPR("quota");
256MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_QUOTA);
257MODULE_DESCRIPTION("Netfilter nftables quota module");