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