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,bool * report)21 static inline bool nft_overquota(struct nft_quota *priv,
22 const struct sk_buff *skb,
23 bool *report)
24 {
25 u64 consumed = atomic64_add_return(skb->len, priv->consumed);
26 u64 quota = atomic64_read(&priv->quota);
27
28 if (report)
29 *report = consumed >= quota;
30
31 return consumed > quota;
32 }
33
nft_quota_invert(struct nft_quota * priv)34 static inline bool nft_quota_invert(struct nft_quota *priv)
35 {
36 return priv->flags & NFT_QUOTA_F_INV;
37 }
38
nft_quota_do_eval(struct nft_quota * priv,struct nft_regs * regs,const struct nft_pktinfo * pkt)39 static inline void nft_quota_do_eval(struct nft_quota *priv,
40 struct nft_regs *regs,
41 const struct nft_pktinfo *pkt)
42 {
43 if (nft_overquota(priv, pkt->skb, NULL) ^ nft_quota_invert(priv))
44 regs->verdict.code = NFT_BREAK;
45 }
46
47 static const struct nla_policy nft_quota_policy[NFTA_QUOTA_MAX + 1] = {
48 [NFTA_QUOTA_BYTES] = { .type = NLA_U64 },
49 [NFTA_QUOTA_FLAGS] = { .type = NLA_U32 },
50 [NFTA_QUOTA_CONSUMED] = { .type = NLA_U64 },
51 };
52
53 #define NFT_QUOTA_DEPLETED_BIT 1 /* From NFT_QUOTA_F_DEPLETED. */
54
nft_quota_obj_eval(struct nft_object * obj,struct nft_regs * regs,const struct nft_pktinfo * pkt)55 static void nft_quota_obj_eval(struct nft_object *obj,
56 struct nft_regs *regs,
57 const struct nft_pktinfo *pkt)
58 {
59 struct nft_quota *priv = nft_obj_data(obj);
60 bool overquota, report;
61
62 overquota = nft_overquota(priv, pkt->skb, &report);
63 if (overquota ^ nft_quota_invert(priv))
64 regs->verdict.code = NFT_BREAK;
65
66 if (report &&
67 !test_and_set_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags))
68 nft_obj_notify(nft_net(pkt), obj->key.table, obj, 0, 0,
69 NFT_MSG_NEWOBJ, 0, nft_pf(pkt), 0, GFP_ATOMIC);
70 }
71
nft_quota_do_init(const struct nlattr * const tb[],struct nft_quota * priv)72 static int nft_quota_do_init(const struct nlattr * const tb[],
73 struct nft_quota *priv)
74 {
75 unsigned long flags = 0;
76 u64 quota, consumed = 0;
77
78 if (!tb[NFTA_QUOTA_BYTES])
79 return -EINVAL;
80
81 quota = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_BYTES]));
82 if (quota > S64_MAX)
83 return -EOVERFLOW;
84
85 if (tb[NFTA_QUOTA_CONSUMED]) {
86 consumed = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_CONSUMED]));
87 if (consumed > quota)
88 return -EINVAL;
89 }
90
91 if (tb[NFTA_QUOTA_FLAGS]) {
92 flags = ntohl(nla_get_be32(tb[NFTA_QUOTA_FLAGS]));
93 if (flags & ~NFT_QUOTA_F_INV)
94 return -EINVAL;
95 if (flags & NFT_QUOTA_F_DEPLETED)
96 return -EOPNOTSUPP;
97 }
98
99 priv->consumed = kmalloc(sizeof(*priv->consumed), GFP_KERNEL_ACCOUNT);
100 if (!priv->consumed)
101 return -ENOMEM;
102
103 atomic64_set(&priv->quota, quota);
104 priv->flags = flags;
105 atomic64_set(priv->consumed, consumed);
106
107 return 0;
108 }
109
nft_quota_do_destroy(const struct nft_ctx * ctx,struct nft_quota * priv)110 static void nft_quota_do_destroy(const struct nft_ctx *ctx,
111 struct nft_quota *priv)
112 {
113 kfree(priv->consumed);
114 }
115
nft_quota_obj_init(const struct nft_ctx * ctx,const struct nlattr * const tb[],struct nft_object * obj)116 static int nft_quota_obj_init(const struct nft_ctx *ctx,
117 const struct nlattr * const tb[],
118 struct nft_object *obj)
119 {
120 struct nft_quota *priv = nft_obj_data(obj);
121
122 return nft_quota_do_init(tb, priv);
123 }
124
nft_quota_obj_update(struct nft_object * obj,struct nft_object * newobj)125 static void nft_quota_obj_update(struct nft_object *obj,
126 struct nft_object *newobj)
127 {
128 struct nft_quota *newpriv = nft_obj_data(newobj);
129 struct nft_quota *priv = nft_obj_data(obj);
130 u64 newquota;
131
132 newquota = atomic64_read(&newpriv->quota);
133 atomic64_set(&priv->quota, newquota);
134 priv->flags = newpriv->flags;
135 }
136
nft_quota_do_dump(struct sk_buff * skb,struct nft_quota * priv,bool reset)137 static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv,
138 bool reset)
139 {
140 u64 consumed, consumed_cap, quota;
141 u32 flags = priv->flags;
142
143 /* Since we inconditionally increment consumed quota for each packet
144 * that we see, don't go over the quota boundary in what we send to
145 * userspace.
146 */
147 consumed = atomic64_read(priv->consumed);
148 quota = atomic64_read(&priv->quota);
149 if (consumed >= quota) {
150 consumed_cap = quota;
151 flags |= NFT_QUOTA_F_DEPLETED;
152 } else {
153 consumed_cap = consumed;
154 }
155
156 if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(quota),
157 NFTA_QUOTA_PAD) ||
158 nla_put_be64(skb, NFTA_QUOTA_CONSUMED, cpu_to_be64(consumed_cap),
159 NFTA_QUOTA_PAD) ||
160 nla_put_be32(skb, NFTA_QUOTA_FLAGS, htonl(flags)))
161 goto nla_put_failure;
162
163 if (reset) {
164 atomic64_sub(consumed, priv->consumed);
165 clear_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags);
166 }
167 return 0;
168
169 nla_put_failure:
170 return -1;
171 }
172
nft_quota_obj_dump(struct sk_buff * skb,struct nft_object * obj,bool reset)173 static int nft_quota_obj_dump(struct sk_buff *skb, struct nft_object *obj,
174 bool reset)
175 {
176 struct nft_quota *priv = nft_obj_data(obj);
177
178 return nft_quota_do_dump(skb, priv, reset);
179 }
180
nft_quota_obj_destroy(const struct nft_ctx * ctx,struct nft_object * obj)181 static void nft_quota_obj_destroy(const struct nft_ctx *ctx,
182 struct nft_object *obj)
183 {
184 struct nft_quota *priv = nft_obj_data(obj);
185
186 return nft_quota_do_destroy(ctx, priv);
187 }
188
189 static struct nft_object_type nft_quota_obj_type;
190 static const struct nft_object_ops nft_quota_obj_ops = {
191 .type = &nft_quota_obj_type,
192 .size = sizeof(struct nft_quota),
193 .init = nft_quota_obj_init,
194 .destroy = nft_quota_obj_destroy,
195 .eval = nft_quota_obj_eval,
196 .dump = nft_quota_obj_dump,
197 .update = nft_quota_obj_update,
198 };
199
200 static struct nft_object_type nft_quota_obj_type __read_mostly = {
201 .type = NFT_OBJECT_QUOTA,
202 .ops = &nft_quota_obj_ops,
203 .maxattr = NFTA_QUOTA_MAX,
204 .policy = nft_quota_policy,
205 .owner = THIS_MODULE,
206 };
207
nft_quota_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)208 static void nft_quota_eval(const struct nft_expr *expr,
209 struct nft_regs *regs,
210 const struct nft_pktinfo *pkt)
211 {
212 struct nft_quota *priv = nft_expr_priv(expr);
213
214 nft_quota_do_eval(priv, regs, pkt);
215 }
216
nft_quota_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])217 static int nft_quota_init(const struct nft_ctx *ctx,
218 const struct nft_expr *expr,
219 const struct nlattr * const tb[])
220 {
221 struct nft_quota *priv = nft_expr_priv(expr);
222
223 return nft_quota_do_init(tb, priv);
224 }
225
nft_quota_dump(struct sk_buff * skb,const struct nft_expr * expr,bool reset)226 static int nft_quota_dump(struct sk_buff *skb,
227 const struct nft_expr *expr, bool reset)
228 {
229 struct nft_quota *priv = nft_expr_priv(expr);
230
231 return nft_quota_do_dump(skb, priv, reset);
232 }
233
nft_quota_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)234 static void nft_quota_destroy(const struct nft_ctx *ctx,
235 const struct nft_expr *expr)
236 {
237 struct nft_quota *priv = nft_expr_priv(expr);
238
239 return nft_quota_do_destroy(ctx, priv);
240 }
241
nft_quota_clone(struct nft_expr * dst,const struct nft_expr * src,gfp_t gfp)242 static int nft_quota_clone(struct nft_expr *dst, const struct nft_expr *src, gfp_t gfp)
243 {
244 struct nft_quota *priv_dst = nft_expr_priv(dst);
245 struct nft_quota *priv_src = nft_expr_priv(src);
246
247 priv_dst->quota = priv_src->quota;
248 priv_dst->flags = priv_src->flags;
249
250 priv_dst->consumed = kmalloc(sizeof(*priv_dst->consumed), gfp);
251 if (!priv_dst->consumed)
252 return -ENOMEM;
253
254 *priv_dst->consumed = *priv_src->consumed;
255
256 return 0;
257 }
258
259 static struct nft_expr_type nft_quota_type;
260 static const struct nft_expr_ops nft_quota_ops = {
261 .type = &nft_quota_type,
262 .size = NFT_EXPR_SIZE(sizeof(struct nft_quota)),
263 .eval = nft_quota_eval,
264 .init = nft_quota_init,
265 .destroy = nft_quota_destroy,
266 .clone = nft_quota_clone,
267 .dump = nft_quota_dump,
268 .reduce = NFT_REDUCE_READONLY,
269 };
270
271 static struct nft_expr_type nft_quota_type __read_mostly = {
272 .name = "quota",
273 .ops = &nft_quota_ops,
274 .policy = nft_quota_policy,
275 .maxattr = NFTA_QUOTA_MAX,
276 .flags = NFT_EXPR_STATEFUL,
277 .owner = THIS_MODULE,
278 };
279
nft_quota_module_init(void)280 static int __init nft_quota_module_init(void)
281 {
282 int err;
283
284 err = nft_register_obj(&nft_quota_obj_type);
285 if (err < 0)
286 return err;
287
288 err = nft_register_expr(&nft_quota_type);
289 if (err < 0)
290 goto err1;
291
292 return 0;
293 err1:
294 nft_unregister_obj(&nft_quota_obj_type);
295 return err;
296 }
297
nft_quota_module_exit(void)298 static void __exit nft_quota_module_exit(void)
299 {
300 nft_unregister_expr(&nft_quota_type);
301 nft_unregister_obj(&nft_quota_obj_type);
302 }
303
304 module_init(nft_quota_module_init);
305 module_exit(nft_quota_module_exit);
306
307 MODULE_LICENSE("GPL");
308 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
309 MODULE_ALIAS_NFT_EXPR("quota");
310 MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_QUOTA);
311 MODULE_DESCRIPTION("Netfilter nftables quota module");
312