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290180e2 PNA |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #include <linux/kernel.h> | |
3 | #include <linux/init.h> | |
4 | #include <linux/module.h> | |
5 | #include <linux/spinlock.h> | |
6 | #include <linux/netlink.h> | |
7 | #include <linux/netfilter.h> | |
8 | #include <linux/netfilter/nf_tables.h> | |
9 | #include <net/netfilter/nf_tables.h> | |
10 | #include <net/netfilter/nf_conntrack.h> | |
11 | #include <net/netfilter/nf_conntrack_count.h> | |
12 | #include <net/netfilter/nf_conntrack_core.h> | |
13 | #include <net/netfilter/nf_conntrack_tuple.h> | |
14 | #include <net/netfilter/nf_conntrack_zones.h> | |
15 | ||
16 | struct nft_connlimit { | |
37f319f3 | 17 | struct nf_conncount_list *list; |
cb2b36f5 YHW |
18 | u32 limit; |
19 | bool invert; | |
290180e2 PNA |
20 | }; |
21 | ||
22 | static inline void nft_connlimit_do_eval(struct nft_connlimit *priv, | |
23 | struct nft_regs *regs, | |
24 | const struct nft_pktinfo *pkt, | |
25 | const struct nft_set_ext *ext) | |
26 | { | |
27 | const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt; | |
28 | const struct nf_conntrack_tuple *tuple_ptr; | |
29 | struct nf_conntrack_tuple tuple; | |
30 | enum ip_conntrack_info ctinfo; | |
31 | const struct nf_conn *ct; | |
32 | unsigned int count; | |
290180e2 PNA |
33 | |
34 | tuple_ptr = &tuple; | |
35 | ||
36 | ct = nf_ct_get(pkt->skb, &ctinfo); | |
37 | if (ct != NULL) { | |
38 | tuple_ptr = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; | |
39 | zone = nf_ct_zone(ct); | |
40 | } else if (!nf_ct_get_tuplepr(pkt->skb, skb_network_offset(pkt->skb), | |
41 | nft_pf(pkt), nft_net(pkt), &tuple)) { | |
42 | regs->verdict.code = NF_DROP; | |
43 | return; | |
44 | } | |
45 | ||
37f319f3 | 46 | if (nf_conncount_add(nft_net(pkt), priv->list, tuple_ptr, zone)) { |
290180e2 | 47 | regs->verdict.code = NF_DROP; |
290180e2 PNA |
48 | return; |
49 | } | |
df4a9025 | 50 | |
37f319f3 | 51 | count = priv->list->count; |
290180e2 PNA |
52 | |
53 | if ((count > priv->limit) ^ priv->invert) { | |
54 | regs->verdict.code = NFT_BREAK; | |
55 | return; | |
56 | } | |
57 | } | |
58 | ||
59 | static int nft_connlimit_do_init(const struct nft_ctx *ctx, | |
60 | const struct nlattr * const tb[], | |
61 | struct nft_connlimit *priv) | |
62 | { | |
63 | bool invert = false; | |
64 | u32 flags, limit; | |
7d70984a | 65 | int err; |
290180e2 PNA |
66 | |
67 | if (!tb[NFTA_CONNLIMIT_COUNT]) | |
68 | return -EINVAL; | |
69 | ||
70 | limit = ntohl(nla_get_be32(tb[NFTA_CONNLIMIT_COUNT])); | |
71 | ||
72 | if (tb[NFTA_CONNLIMIT_FLAGS]) { | |
73 | flags = ntohl(nla_get_be32(tb[NFTA_CONNLIMIT_FLAGS])); | |
74 | if (flags & ~NFT_CONNLIMIT_F_INV) | |
75 | return -EOPNOTSUPP; | |
76 | if (flags & NFT_CONNLIMIT_F_INV) | |
77 | invert = true; | |
78 | } | |
79 | ||
42193ffd | 80 | priv->list = kmalloc(sizeof(*priv->list), GFP_KERNEL_ACCOUNT); |
37f319f3 PNA |
81 | if (!priv->list) |
82 | return -ENOMEM; | |
83 | ||
84 | nf_conncount_list_init(priv->list); | |
290180e2 PNA |
85 | priv->limit = limit; |
86 | priv->invert = invert; | |
87 | ||
7d70984a PNA |
88 | err = nf_ct_netns_get(ctx->net, ctx->family); |
89 | if (err < 0) | |
90 | goto err_netns; | |
91 | ||
92 | return 0; | |
93 | err_netns: | |
94 | kfree(priv->list); | |
95 | ||
96 | return err; | |
290180e2 PNA |
97 | } |
98 | ||
99 | static void nft_connlimit_do_destroy(const struct nft_ctx *ctx, | |
100 | struct nft_connlimit *priv) | |
101 | { | |
102 | nf_ct_netns_put(ctx->net, ctx->family); | |
37f319f3 PNA |
103 | nf_conncount_cache_free(priv->list); |
104 | kfree(priv->list); | |
290180e2 PNA |
105 | } |
106 | ||
107 | static int nft_connlimit_do_dump(struct sk_buff *skb, | |
108 | struct nft_connlimit *priv) | |
109 | { | |
110 | if (nla_put_be32(skb, NFTA_CONNLIMIT_COUNT, htonl(priv->limit))) | |
111 | goto nla_put_failure; | |
112 | if (priv->invert && | |
113 | nla_put_be32(skb, NFTA_CONNLIMIT_FLAGS, htonl(NFT_CONNLIMIT_F_INV))) | |
114 | goto nla_put_failure; | |
115 | ||
116 | return 0; | |
117 | ||
118 | nla_put_failure: | |
119 | return -1; | |
120 | } | |
121 | ||
122 | static inline void nft_connlimit_obj_eval(struct nft_object *obj, | |
123 | struct nft_regs *regs, | |
124 | const struct nft_pktinfo *pkt) | |
125 | { | |
126 | struct nft_connlimit *priv = nft_obj_data(obj); | |
127 | ||
128 | nft_connlimit_do_eval(priv, regs, pkt, NULL); | |
129 | } | |
130 | ||
131 | static int nft_connlimit_obj_init(const struct nft_ctx *ctx, | |
132 | const struct nlattr * const tb[], | |
133 | struct nft_object *obj) | |
134 | { | |
135 | struct nft_connlimit *priv = nft_obj_data(obj); | |
136 | ||
137 | return nft_connlimit_do_init(ctx, tb, priv); | |
138 | } | |
139 | ||
140 | static void nft_connlimit_obj_destroy(const struct nft_ctx *ctx, | |
141 | struct nft_object *obj) | |
142 | { | |
143 | struct nft_connlimit *priv = nft_obj_data(obj); | |
144 | ||
145 | nft_connlimit_do_destroy(ctx, priv); | |
146 | } | |
147 | ||
148 | static int nft_connlimit_obj_dump(struct sk_buff *skb, | |
149 | struct nft_object *obj, bool reset) | |
150 | { | |
151 | struct nft_connlimit *priv = nft_obj_data(obj); | |
152 | ||
153 | return nft_connlimit_do_dump(skb, priv); | |
154 | } | |
155 | ||
156 | static const struct nla_policy nft_connlimit_policy[NFTA_CONNLIMIT_MAX + 1] = { | |
157 | [NFTA_CONNLIMIT_COUNT] = { .type = NLA_U32 }, | |
158 | [NFTA_CONNLIMIT_FLAGS] = { .type = NLA_U32 }, | |
159 | }; | |
160 | ||
161 | static struct nft_object_type nft_connlimit_obj_type; | |
162 | static const struct nft_object_ops nft_connlimit_obj_ops = { | |
163 | .type = &nft_connlimit_obj_type, | |
164 | .size = sizeof(struct nft_connlimit), | |
165 | .eval = nft_connlimit_obj_eval, | |
166 | .init = nft_connlimit_obj_init, | |
167 | .destroy = nft_connlimit_obj_destroy, | |
168 | .dump = nft_connlimit_obj_dump, | |
169 | }; | |
170 | ||
171 | static struct nft_object_type nft_connlimit_obj_type __read_mostly = { | |
172 | .type = NFT_OBJECT_CONNLIMIT, | |
173 | .ops = &nft_connlimit_obj_ops, | |
174 | .maxattr = NFTA_CONNLIMIT_MAX, | |
175 | .policy = nft_connlimit_policy, | |
176 | .owner = THIS_MODULE, | |
177 | }; | |
178 | ||
179 | static void nft_connlimit_eval(const struct nft_expr *expr, | |
180 | struct nft_regs *regs, | |
181 | const struct nft_pktinfo *pkt) | |
182 | { | |
183 | struct nft_connlimit *priv = nft_expr_priv(expr); | |
184 | ||
185 | nft_connlimit_do_eval(priv, regs, pkt, NULL); | |
186 | } | |
187 | ||
7d34aa3e PS |
188 | static int nft_connlimit_dump(struct sk_buff *skb, |
189 | const struct nft_expr *expr, bool reset) | |
290180e2 PNA |
190 | { |
191 | struct nft_connlimit *priv = nft_expr_priv(expr); | |
192 | ||
193 | return nft_connlimit_do_dump(skb, priv); | |
194 | } | |
195 | ||
196 | static int nft_connlimit_init(const struct nft_ctx *ctx, | |
197 | const struct nft_expr *expr, | |
198 | const struct nlattr * const tb[]) | |
199 | { | |
200 | struct nft_connlimit *priv = nft_expr_priv(expr); | |
201 | ||
202 | return nft_connlimit_do_init(ctx, tb, priv); | |
203 | } | |
204 | ||
205 | static void nft_connlimit_destroy(const struct nft_ctx *ctx, | |
206 | const struct nft_expr *expr) | |
207 | { | |
208 | struct nft_connlimit *priv = nft_expr_priv(expr); | |
209 | ||
210 | nft_connlimit_do_destroy(ctx, priv); | |
211 | } | |
212 | ||
213 | static int nft_connlimit_clone(struct nft_expr *dst, const struct nft_expr *src) | |
214 | { | |
215 | struct nft_connlimit *priv_dst = nft_expr_priv(dst); | |
216 | struct nft_connlimit *priv_src = nft_expr_priv(src); | |
217 | ||
37f319f3 | 218 | priv_dst->list = kmalloc(sizeof(*priv_dst->list), GFP_ATOMIC); |
51edb2ff | 219 | if (!priv_dst->list) |
37f319f3 PNA |
220 | return -ENOMEM; |
221 | ||
222 | nf_conncount_list_init(priv_dst->list); | |
290180e2 PNA |
223 | priv_dst->limit = priv_src->limit; |
224 | priv_dst->invert = priv_src->invert; | |
225 | ||
226 | return 0; | |
227 | } | |
228 | ||
229 | static void nft_connlimit_destroy_clone(const struct nft_ctx *ctx, | |
230 | const struct nft_expr *expr) | |
231 | { | |
232 | struct nft_connlimit *priv = nft_expr_priv(expr); | |
233 | ||
37f319f3 PNA |
234 | nf_conncount_cache_free(priv->list); |
235 | kfree(priv->list); | |
290180e2 PNA |
236 | } |
237 | ||
238 | static bool nft_connlimit_gc(struct net *net, const struct nft_expr *expr) | |
239 | { | |
240 | struct nft_connlimit *priv = nft_expr_priv(expr); | |
34a4c95a | 241 | bool ret; |
290180e2 | 242 | |
34a4c95a | 243 | local_bh_disable(); |
37f319f3 | 244 | ret = nf_conncount_gc_list(net, priv->list); |
34a4c95a PNA |
245 | local_bh_enable(); |
246 | ||
247 | return ret; | |
290180e2 PNA |
248 | } |
249 | ||
250 | static struct nft_expr_type nft_connlimit_type; | |
251 | static const struct nft_expr_ops nft_connlimit_ops = { | |
252 | .type = &nft_connlimit_type, | |
253 | .size = NFT_EXPR_SIZE(sizeof(struct nft_connlimit)), | |
254 | .eval = nft_connlimit_eval, | |
255 | .init = nft_connlimit_init, | |
256 | .destroy = nft_connlimit_destroy, | |
257 | .clone = nft_connlimit_clone, | |
258 | .destroy_clone = nft_connlimit_destroy_clone, | |
259 | .dump = nft_connlimit_dump, | |
260 | .gc = nft_connlimit_gc, | |
b2d30654 | 261 | .reduce = NFT_REDUCE_READONLY, |
290180e2 PNA |
262 | }; |
263 | ||
264 | static struct nft_expr_type nft_connlimit_type __read_mostly = { | |
265 | .name = "connlimit", | |
266 | .ops = &nft_connlimit_ops, | |
267 | .policy = nft_connlimit_policy, | |
268 | .maxattr = NFTA_CONNLIMIT_MAX, | |
269 | .flags = NFT_EXPR_STATEFUL | NFT_EXPR_GC, | |
270 | .owner = THIS_MODULE, | |
271 | }; | |
272 | ||
273 | static int __init nft_connlimit_module_init(void) | |
274 | { | |
275 | int err; | |
276 | ||
277 | err = nft_register_obj(&nft_connlimit_obj_type); | |
278 | if (err < 0) | |
279 | return err; | |
280 | ||
281 | err = nft_register_expr(&nft_connlimit_type); | |
282 | if (err < 0) | |
283 | goto err1; | |
284 | ||
285 | return 0; | |
286 | err1: | |
287 | nft_unregister_obj(&nft_connlimit_obj_type); | |
288 | return err; | |
289 | } | |
290 | ||
291 | static void __exit nft_connlimit_module_exit(void) | |
292 | { | |
293 | nft_unregister_expr(&nft_connlimit_type); | |
294 | nft_unregister_obj(&nft_connlimit_obj_type); | |
295 | } | |
296 | ||
297 | module_init(nft_connlimit_module_init); | |
298 | module_exit(nft_connlimit_module_exit); | |
299 | ||
300 | MODULE_LICENSE("GPL"); | |
301 | MODULE_AUTHOR("Pablo Neira Ayuso"); | |
302 | MODULE_ALIAS_NFT_EXPR("connlimit"); | |
303 | MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_CONNLIMIT); | |
4cacc395 | 304 | MODULE_DESCRIPTION("nftables connlimit rule support"); |