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
15 struct nft_quota {
16 atomic64_t quota;
17 unsigned long flags;
18 atomic64_t *consumed;
19 };
20
nft_overquota(struct nft_quota * priv,const struct sk_buff * skb)21 static 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
nft_quota_invert(struct nft_quota * priv)28 static inline bool nft_quota_invert(struct nft_quota *priv)
29 {
30 return priv->flags & NFT_QUOTA_F_INV;
31 }
32
nft_quota_do_eval(struct nft_quota * priv,struct nft_regs * regs,const struct nft_pktinfo * pkt)33 static 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
41 static 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
nft_quota_obj_eval(struct nft_object * obj,struct nft_regs * regs,const struct nft_pktinfo * pkt)49 static 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
nft_quota_do_init(const struct nlattr * const tb[],struct nft_quota * priv)66 static 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 priv->consumed = kmalloc(sizeof(*priv->consumed), GFP_KERNEL_ACCOUNT);
94 if (!priv->consumed)
95 return -ENOMEM;
96
97 atomic64_set(&priv->quota, quota);
98 priv->flags = flags;
99 atomic64_set(priv->consumed, consumed);
100
101 return 0;
102 }
103
nft_quota_do_destroy(const struct nft_ctx * ctx,struct nft_quota * priv)104 static void nft_quota_do_destroy(const struct nft_ctx *ctx,
105 struct nft_quota *priv)
106 {
107 kfree(priv->consumed);
108 }
109
nft_quota_obj_init(const struct nft_ctx * ctx,const struct nlattr * const tb[],struct nft_object * obj)110 static int nft_quota_obj_init(const struct nft_ctx *ctx,
111 const struct nlattr * const tb[],
112 struct nft_object *obj)
113 {
114 struct nft_quota *priv = nft_obj_data(obj);
115
116 return nft_quota_do_init(tb, priv);
117 }
118
nft_quota_obj_update(struct nft_object * obj,struct nft_object * newobj)119 static void nft_quota_obj_update(struct nft_object *obj,
120 struct nft_object *newobj)
121 {
122 struct nft_quota *newpriv = nft_obj_data(newobj);
123 struct nft_quota *priv = nft_obj_data(obj);
124 u64 newquota;
125
126 newquota = atomic64_read(&newpriv->quota);
127 atomic64_set(&priv->quota, newquota);
128 priv->flags = newpriv->flags;
129 }
130
nft_quota_do_dump(struct sk_buff * skb,struct nft_quota * priv,bool reset)131 static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv,
132 bool reset)
133 {
134 u64 consumed, consumed_cap, quota;
135 u32 flags = priv->flags;
136
137 /* Since we inconditionally increment consumed quota for each packet
138 * that we see, don't go over the quota boundary in what we send to
139 * userspace.
140 */
141 consumed = atomic64_read(priv->consumed);
142 quota = atomic64_read(&priv->quota);
143 if (consumed >= quota) {
144 consumed_cap = quota;
145 flags |= NFT_QUOTA_F_DEPLETED;
146 } else {
147 consumed_cap = consumed;
148 }
149
150 if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(quota),
151 NFTA_QUOTA_PAD) ||
152 nla_put_be64(skb, NFTA_QUOTA_CONSUMED, cpu_to_be64(consumed_cap),
153 NFTA_QUOTA_PAD) ||
154 nla_put_be32(skb, NFTA_QUOTA_FLAGS, htonl(flags)))
155 goto nla_put_failure;
156
157 if (reset) {
158 atomic64_sub(consumed, priv->consumed);
159 clear_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags);
160 }
161 return 0;
162
163 nla_put_failure:
164 return -1;
165 }
166
nft_quota_obj_dump(struct sk_buff * skb,struct nft_object * obj,bool reset)167 static int nft_quota_obj_dump(struct sk_buff *skb, struct nft_object *obj,
168 bool reset)
169 {
170 struct nft_quota *priv = nft_obj_data(obj);
171
172 return nft_quota_do_dump(skb, priv, reset);
173 }
174
nft_quota_obj_destroy(const struct nft_ctx * ctx,struct nft_object * obj)175 static void nft_quota_obj_destroy(const struct nft_ctx *ctx,
176 struct nft_object *obj)
177 {
178 struct nft_quota *priv = nft_obj_data(obj);
179
180 return nft_quota_do_destroy(ctx, priv);
181 }
182
183 static struct nft_object_type nft_quota_obj_type;
184 static const struct nft_object_ops nft_quota_obj_ops = {
185 .type = &nft_quota_obj_type,
186 .size = sizeof(struct nft_quota),
187 .init = nft_quota_obj_init,
188 .destroy = nft_quota_obj_destroy,
189 .eval = nft_quota_obj_eval,
190 .dump = nft_quota_obj_dump,
191 .update = nft_quota_obj_update,
192 };
193
194 static struct nft_object_type nft_quota_obj_type __read_mostly = {
195 .type = NFT_OBJECT_QUOTA,
196 .ops = &nft_quota_obj_ops,
197 .maxattr = NFTA_QUOTA_MAX,
198 .policy = nft_quota_policy,
199 .owner = THIS_MODULE,
200 };
201
nft_quota_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)202 static void nft_quota_eval(const struct nft_expr *expr,
203 struct nft_regs *regs,
204 const struct nft_pktinfo *pkt)
205 {
206 struct nft_quota *priv = nft_expr_priv(expr);
207
208 nft_quota_do_eval(priv, regs, pkt);
209 }
210
nft_quota_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])211 static int nft_quota_init(const struct nft_ctx *ctx,
212 const struct nft_expr *expr,
213 const struct nlattr * const tb[])
214 {
215 struct nft_quota *priv = nft_expr_priv(expr);
216
217 return nft_quota_do_init(tb, priv);
218 }
219
nft_quota_dump(struct sk_buff * skb,const struct nft_expr * expr,bool reset)220 static int nft_quota_dump(struct sk_buff *skb,
221 const struct nft_expr *expr, bool reset)
222 {
223 struct nft_quota *priv = nft_expr_priv(expr);
224
225 return nft_quota_do_dump(skb, priv, reset);
226 }
227
nft_quota_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)228 static void nft_quota_destroy(const struct nft_ctx *ctx,
229 const struct nft_expr *expr)
230 {
231 struct nft_quota *priv = nft_expr_priv(expr);
232
233 return nft_quota_do_destroy(ctx, priv);
234 }
235
nft_quota_clone(struct nft_expr * dst,const struct nft_expr * src)236 static int nft_quota_clone(struct nft_expr *dst, const struct nft_expr *src)
237 {
238 struct nft_quota *priv_dst = nft_expr_priv(dst);
239 struct nft_quota *priv_src = nft_expr_priv(src);
240
241 priv_dst->quota = priv_src->quota;
242 priv_dst->flags = priv_src->flags;
243
244 priv_dst->consumed = kmalloc(sizeof(*priv_dst->consumed), GFP_ATOMIC);
245 if (!priv_dst->consumed)
246 return -ENOMEM;
247
248 *priv_dst->consumed = *priv_src->consumed;
249
250 return 0;
251 }
252
253 static struct nft_expr_type nft_quota_type;
254 static const struct nft_expr_ops nft_quota_ops = {
255 .type = &nft_quota_type,
256 .size = NFT_EXPR_SIZE(sizeof(struct nft_quota)),
257 .eval = nft_quota_eval,
258 .init = nft_quota_init,
259 .destroy = nft_quota_destroy,
260 .clone = nft_quota_clone,
261 .dump = nft_quota_dump,
262 .reduce = NFT_REDUCE_READONLY,
263 };
264
265 static struct nft_expr_type nft_quota_type __read_mostly = {
266 .name = "quota",
267 .ops = &nft_quota_ops,
268 .policy = nft_quota_policy,
269 .maxattr = NFTA_QUOTA_MAX,
270 .flags = NFT_EXPR_STATEFUL,
271 .owner = THIS_MODULE,
272 };
273
nft_quota_module_init(void)274 static int __init nft_quota_module_init(void)
275 {
276 int err;
277
278 err = nft_register_obj(&nft_quota_obj_type);
279 if (err < 0)
280 return err;
281
282 err = nft_register_expr(&nft_quota_type);
283 if (err < 0)
284 goto err1;
285
286 return 0;
287 err1:
288 nft_unregister_obj(&nft_quota_obj_type);
289 return err;
290 }
291
nft_quota_module_exit(void)292 static void __exit nft_quota_module_exit(void)
293 {
294 nft_unregister_expr(&nft_quota_type);
295 nft_unregister_obj(&nft_quota_obj_type);
296 }
297
298 module_init(nft_quota_module_init);
299 module_exit(nft_quota_module_exit);
300
301 MODULE_LICENSE("GPL");
302 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
303 MODULE_ALIAS_NFT_EXPR("quota");
304 MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_QUOTA);
305 MODULE_DESCRIPTION("Netfilter nftables quota module");
306
