summaryrefslogtreecommitdiff
path: root/net/netfilter/nft_connlimit.c
blob: 7d0761fad37ef560af1b299007497ce1049a6a3c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_count.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_tuple.h>
#include <net/netfilter/nf_conntrack_zones.h>

struct nft_connlimit {
	struct nf_conncount_list	list;
	u32				limit;
	bool				invert;
};

static inline void nft_connlimit_do_eval(struct nft_connlimit *priv,
					 struct nft_regs *regs,
					 const struct nft_pktinfo *pkt,
					 const struct nft_set_ext *ext)
{
	const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt;
	const struct nf_conntrack_tuple *tuple_ptr;
	struct nf_conntrack_tuple tuple;
	enum ip_conntrack_info ctinfo;
	const struct nf_conn *ct;
	unsigned int count;

	tuple_ptr = &tuple;

	ct = nf_ct_get(pkt->skb, &ctinfo);
	if (ct != NULL) {
		tuple_ptr = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
		zone = nf_ct_zone(ct);
	} else if (!nf_ct_get_tuplepr(pkt->skb, skb_network_offset(pkt->skb),
				      nft_pf(pkt), nft_net(pkt), &tuple)) {
		regs->verdict.code = NF_DROP;
		return;
	}

	if (nf_conncount_add(nft_net(pkt), &priv->list, tuple_ptr, zone)) {
		regs->verdict.code = NF_DROP;
		return;
	}

	count = priv->list.count;

	if ((count > priv->limit) ^ priv->invert) {
		regs->verdict.code = NFT_BREAK;
		return;
	}
}

static int nft_connlimit_do_init(const struct nft_ctx *ctx,
				 const struct nlattr * const tb[],
				 struct nft_connlimit *priv)
{
	bool invert = false;
	u32 flags, limit;

	if (!tb[NFTA_CONNLIMIT_COUNT])
		return -EINVAL;

	limit = ntohl(nla_get_be32(tb[NFTA_CONNLIMIT_COUNT]));

	if (tb[NFTA_CONNLIMIT_FLAGS]) {
		flags = ntohl(nla_get_be32(tb[NFTA_CONNLIMIT_FLAGS]));
		if (flags & ~NFT_CONNLIMIT_F_INV)
			return -EOPNOTSUPP;
		if (flags & NFT_CONNLIMIT_F_INV)
			invert = true;
	}

	nf_conncount_list_init(&priv->list);
	priv->limit	= limit;
	priv->invert	= invert;

	return nf_ct_netns_get(ctx->net, ctx->family);
}

static void nft_connlimit_do_destroy(const struct nft_ctx *ctx,
				     struct nft_connlimit *priv)
{
	nf_ct_netns_put(ctx->net, ctx->family);
	nf_conncount_cache_free(&priv->list);
}

static int nft_connlimit_do_dump(struct sk_buff *skb,
				 struct nft_connlimit *priv)
{
	if (nla_put_be32(skb, NFTA_CONNLIMIT_COUNT, htonl(priv->limit)))
		goto nla_put_failure;
	if (priv->invert &&
	    nla_put_be32(skb, NFTA_CONNLIMIT_FLAGS, htonl(NFT_CONNLIMIT_F_INV)))
		goto nla_put_failure;

	return 0;

nla_put_failure:
	return -1;
}

static inline void nft_connlimit_obj_eval(struct nft_object *obj,
					struct nft_regs *regs,
					const struct nft_pktinfo *pkt)
{
	struct nft_connlimit *priv = nft_obj_data(obj);

	nft_connlimit_do_eval(priv, regs, pkt, NULL);
}

static int nft_connlimit_obj_init(const struct nft_ctx *ctx,
				const struct nlattr * const tb[],
				struct nft_object *obj)
{
	struct nft_connlimit *priv = nft_obj_data(obj);

	return nft_connlimit_do_init(ctx, tb, priv);
}

static void nft_connlimit_obj_destroy(const struct nft_ctx *ctx,
				      struct nft_object *obj)
{
	struct nft_connlimit *priv = nft_obj_data(obj);

	nft_connlimit_do_destroy(ctx, priv);
}

static int nft_connlimit_obj_dump(struct sk_buff *skb,
				  struct nft_object *obj, bool reset)
{
	struct nft_connlimit *priv = nft_obj_data(obj);

	return nft_connlimit_do_dump(skb, priv);
}

static const struct nla_policy nft_connlimit_policy[NFTA_CONNLIMIT_MAX + 1] = {
	[NFTA_CONNLIMIT_COUNT]	= { .type = NLA_U32 },
	[NFTA_CONNLIMIT_FLAGS]	= { .type = NLA_U32 },
};

static struct nft_object_type nft_connlimit_obj_type;
static const struct nft_object_ops nft_connlimit_obj_ops = {
	.type		= &nft_connlimit_obj_type,
	.size		= sizeof(struct nft_connlimit),
	.eval		= nft_connlimit_obj_eval,
	.init		= nft_connlimit_obj_init,
	.destroy	= nft_connlimit_obj_destroy,
	.dump		= nft_connlimit_obj_dump,
};

static struct nft_object_type nft_connlimit_obj_type __read_mostly = {
	.type		= NFT_OBJECT_CONNLIMIT,
	.ops		= &nft_connlimit_obj_ops,
	.maxattr	= NFTA_CONNLIMIT_MAX,
	.policy		= nft_connlimit_policy,
	.owner		= THIS_MODULE,
};

static void nft_connlimit_eval(const struct nft_expr *expr,
			       struct nft_regs *regs,
			       const struct nft_pktinfo *pkt)
{
	struct nft_connlimit *priv = nft_expr_priv(expr);

	nft_connlimit_do_eval(priv, regs, pkt, NULL);
}

static int nft_connlimit_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
	struct nft_connlimit *priv = nft_expr_priv(expr);

	return nft_connlimit_do_dump(skb, priv);
}

static int nft_connlimit_init(const struct nft_ctx *ctx,
			      const struct nft_expr *expr,
			      const struct nlattr * const tb[])
{
	struct nft_connlimit *priv = nft_expr_priv(expr);

	return nft_connlimit_do_init(ctx, tb, priv);
}

static void nft_connlimit_destroy(const struct nft_ctx *ctx,
				const struct nft_expr *expr)
{
	struct nft_connlimit *priv = nft_expr_priv(expr);

	nft_connlimit_do_destroy(ctx, priv);
}

static int nft_connlimit_clone(struct nft_expr *dst, const struct nft_expr *src)
{
	struct nft_connlimit *priv_dst = nft_expr_priv(dst);
	struct nft_connlimit *priv_src = nft_expr_priv(src);

	nf_conncount_list_init(&priv_dst->list);
	priv_dst->limit	 = priv_src->limit;
	priv_dst->invert = priv_src->invert;

	return 0;
}

static void nft_connlimit_destroy_clone(const struct nft_ctx *ctx,
					const struct nft_expr *expr)
{
	struct nft_connlimit *priv = nft_expr_priv(expr);

	nf_conncount_cache_free(&priv->list);
}

static bool nft_connlimit_gc(struct net *net, const struct nft_expr *expr)
{
	struct nft_connlimit *priv = nft_expr_priv(expr);
	bool ret;

	local_bh_disable();
	ret = nf_conncount_gc_list(net, &priv->list);
	local_bh_enable();

	return ret;
}

static struct nft_expr_type nft_connlimit_type;
static const struct nft_expr_ops nft_connlimit_ops = {
	.type		= &nft_connlimit_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_connlimit)),
	.eval		= nft_connlimit_eval,
	.init		= nft_connlimit_init,
	.destroy	= nft_connlimit_destroy,
	.clone		= nft_connlimit_clone,
	.destroy_clone	= nft_connlimit_destroy_clone,
	.dump		= nft_connlimit_dump,
	.gc		= nft_connlimit_gc,
};

static struct nft_expr_type nft_connlimit_type __read_mostly = {
	.name		= "connlimit",
	.ops		= &nft_connlimit_ops,
	.policy		= nft_connlimit_policy,
	.maxattr	= NFTA_CONNLIMIT_MAX,
	.flags		= NFT_EXPR_STATEFUL | NFT_EXPR_GC,
	.owner		= THIS_MODULE,
};

static int __init nft_connlimit_module_init(void)
{
	int err;

	err = nft_register_obj(&nft_connlimit_obj_type);
	if (err < 0)
		return err;

	err = nft_register_expr(&nft_connlimit_type);
	if (err < 0)
		goto err1;

	return 0;
err1:
	nft_unregister_obj(&nft_connlimit_obj_type);
	return err;
}

static void __exit nft_connlimit_module_exit(void)
{
	nft_unregister_expr(&nft_connlimit_type);
	nft_unregister_obj(&nft_connlimit_obj_type);
}

module_init(nft_connlimit_module_init);
module_exit(nft_connlimit_module_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso");
MODULE_ALIAS_NFT_EXPR("connlimit");
MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_CONNLIMIT);
MODULE_DESCRIPTION("nftables connlimit rule support");