summaryrefslogtreecommitdiff
path: root/net/netfilter/nft_lookup.c
blob: d4f97fa7e21d0036690e229768ab097fc5220cfc (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
/*
 * Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Development of this code funded by Astaro AG (http://www.astaro.com/)
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/rbtree.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_tables_core.h>

struct nft_lookup {
	struct nft_set			*set;
	enum nft_registers		sreg:8;
	enum nft_registers		dreg:8;
	bool				invert;
	struct nft_set_binding		binding;
};

static void nft_lookup_eval(const struct nft_expr *expr,
			    struct nft_regs *regs,
			    const struct nft_pktinfo *pkt)
{
	const struct nft_lookup *priv = nft_expr_priv(expr);
	const struct nft_set *set = priv->set;
	const struct nft_set_ext *ext;
	bool found;

	found = set->ops->lookup(nft_net(pkt), set, &regs->data[priv->sreg],
				 &ext) ^ priv->invert;
	if (!found) {
		regs->verdict.code = NFT_BREAK;
		return;
	}

	if (set->flags & NFT_SET_MAP)
		nft_data_copy(&regs->data[priv->dreg],
			      nft_set_ext_data(ext), set->dlen);

}

static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
	[NFTA_LOOKUP_SET]	= { .type = NLA_STRING },
	[NFTA_LOOKUP_SET_ID]	= { .type = NLA_U32 },
	[NFTA_LOOKUP_SREG]	= { .type = NLA_U32 },
	[NFTA_LOOKUP_DREG]	= { .type = NLA_U32 },
	[NFTA_LOOKUP_FLAGS]	= { .type = NLA_U32 },
};

static int nft_lookup_init(const struct nft_ctx *ctx,
			   const struct nft_expr *expr,
			   const struct nlattr * const tb[])
{
	struct nft_lookup *priv = nft_expr_priv(expr);
	u8 genmask = nft_genmask_next(ctx->net);
	struct nft_set *set;
	u32 flags;
	int err;

	if (tb[NFTA_LOOKUP_SET] == NULL ||
	    tb[NFTA_LOOKUP_SREG] == NULL)
		return -EINVAL;

	set = nf_tables_set_lookup(ctx->table, tb[NFTA_LOOKUP_SET], genmask);
	if (IS_ERR(set)) {
		if (tb[NFTA_LOOKUP_SET_ID]) {
			set = nf_tables_set_lookup_byid(ctx->net,
							tb[NFTA_LOOKUP_SET_ID],
							genmask);
		}
		if (IS_ERR(set))
			return PTR_ERR(set);
	}

	if (set->flags & NFT_SET_EVAL)
		return -EOPNOTSUPP;

	priv->sreg = nft_parse_register(tb[NFTA_LOOKUP_SREG]);
	err = nft_validate_register_load(priv->sreg, set->klen);
	if (err < 0)
		return err;

	if (tb[NFTA_LOOKUP_FLAGS]) {
		flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));

		if (flags & ~NFT_LOOKUP_F_INV)
			return -EINVAL;

		if (flags & NFT_LOOKUP_F_INV) {
			if (set->flags & NFT_SET_MAP)
				return -EINVAL;
			priv->invert = true;
		}
	}

	if (tb[NFTA_LOOKUP_DREG] != NULL) {
		if (priv->invert)
			return -EINVAL;
		if (!(set->flags & NFT_SET_MAP))
			return -EINVAL;

		priv->dreg = nft_parse_register(tb[NFTA_LOOKUP_DREG]);
		err = nft_validate_register_store(ctx, priv->dreg, NULL,
						  set->dtype, set->dlen);
		if (err < 0)
			return err;
	} else if (set->flags & NFT_SET_MAP)
		return -EINVAL;

	priv->binding.flags = set->flags & NFT_SET_MAP;

	err = nf_tables_bind_set(ctx, set, &priv->binding);
	if (err < 0)
		return err;

	priv->set = set;
	return 0;
}

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

	nf_tables_unbind_set(ctx, priv->set, &priv->binding);
}

static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
	const struct nft_lookup *priv = nft_expr_priv(expr);
	u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;

	if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
		goto nla_put_failure;
	if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
		goto nla_put_failure;
	if (priv->set->flags & NFT_SET_MAP)
		if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
			goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
		goto nla_put_failure;
	return 0;

nla_put_failure:
	return -1;
}

static const struct nft_expr_ops nft_lookup_ops = {
	.type		= &nft_lookup_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
	.eval		= nft_lookup_eval,
	.init		= nft_lookup_init,
	.destroy	= nft_lookup_destroy,
	.dump		= nft_lookup_dump,
};

struct nft_expr_type nft_lookup_type __read_mostly = {
	.name		= "lookup",
	.ops		= &nft_lookup_ops,
	.policy		= nft_lookup_policy,
	.maxattr	= NFTA_LOOKUP_MAX,
	.owner		= THIS_MODULE,
};