1 /*
2 * Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * Development of this code funded by Astaro AG (http://www.astaro.com/)
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/list.h>
14 #include <linux/rbtree.h>
15 #include <linux/netlink.h>
16 #include <linux/netfilter.h>
17 #include <linux/netfilter/nf_tables.h>
18 #include <net/netfilter/nf_tables.h>
19 #include <net/netfilter/nf_tables_core.h>
20
21 struct nft_lookup {
22 struct nft_set *set;
23 enum nft_registers sreg:8;
24 enum nft_registers dreg:8;
25 bool invert;
26 struct nft_set_binding binding;
27 };
28
nft_lookup_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)29 static void nft_lookup_eval(const struct nft_expr *expr,
30 struct nft_regs *regs,
31 const struct nft_pktinfo *pkt)
32 {
33 const struct nft_lookup *priv = nft_expr_priv(expr);
34 const struct nft_set *set = priv->set;
35 const struct nft_set_ext *ext;
36 bool found;
37
38 found = set->ops->lookup(pkt->net, set, ®s->data[priv->sreg], &ext) ^
39 priv->invert;
40
41 if (!found) {
42 regs->verdict.code = NFT_BREAK;
43 return;
44 }
45
46 if (set->flags & NFT_SET_MAP)
47 nft_data_copy(®s->data[priv->dreg],
48 nft_set_ext_data(ext), set->dlen);
49
50 }
51
52 static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
53 [NFTA_LOOKUP_SET] = { .type = NLA_STRING },
54 [NFTA_LOOKUP_SET_ID] = { .type = NLA_U32 },
55 [NFTA_LOOKUP_SREG] = { .type = NLA_U32 },
56 [NFTA_LOOKUP_DREG] = { .type = NLA_U32 },
57 [NFTA_LOOKUP_FLAGS] = { .type = NLA_U32 },
58 };
59
nft_lookup_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])60 static int nft_lookup_init(const struct nft_ctx *ctx,
61 const struct nft_expr *expr,
62 const struct nlattr * const tb[])
63 {
64 struct nft_lookup *priv = nft_expr_priv(expr);
65 u8 genmask = nft_genmask_next(ctx->net);
66 struct nft_set *set;
67 u32 flags;
68 int err;
69
70 if (tb[NFTA_LOOKUP_SET] == NULL ||
71 tb[NFTA_LOOKUP_SREG] == NULL)
72 return -EINVAL;
73
74 set = nf_tables_set_lookup(ctx->table, tb[NFTA_LOOKUP_SET], genmask);
75 if (IS_ERR(set)) {
76 if (tb[NFTA_LOOKUP_SET_ID]) {
77 set = nf_tables_set_lookup_byid(ctx->net,
78 tb[NFTA_LOOKUP_SET_ID],
79 genmask);
80 }
81 if (IS_ERR(set))
82 return PTR_ERR(set);
83 }
84
85 if (set->flags & NFT_SET_EVAL)
86 return -EOPNOTSUPP;
87
88 priv->sreg = nft_parse_register(tb[NFTA_LOOKUP_SREG]);
89 err = nft_validate_register_load(priv->sreg, set->klen);
90 if (err < 0)
91 return err;
92
93 if (tb[NFTA_LOOKUP_FLAGS]) {
94 flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));
95
96 if (flags & ~NFT_LOOKUP_F_INV)
97 return -EINVAL;
98
99 if (flags & NFT_LOOKUP_F_INV) {
100 if (set->flags & NFT_SET_MAP)
101 return -EINVAL;
102 priv->invert = true;
103 }
104 }
105
106 if (tb[NFTA_LOOKUP_DREG] != NULL) {
107 if (priv->invert)
108 return -EINVAL;
109 if (!(set->flags & NFT_SET_MAP))
110 return -EINVAL;
111
112 priv->dreg = nft_parse_register(tb[NFTA_LOOKUP_DREG]);
113 err = nft_validate_register_store(ctx, priv->dreg, NULL,
114 set->dtype, set->dlen);
115 if (err < 0)
116 return err;
117 } else if (set->flags & NFT_SET_MAP)
118 return -EINVAL;
119
120 priv->binding.flags = set->flags & NFT_SET_MAP;
121
122 err = nf_tables_bind_set(ctx, set, &priv->binding);
123 if (err < 0)
124 return err;
125
126 priv->set = set;
127 return 0;
128 }
129
nft_lookup_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)130 static void nft_lookup_destroy(const struct nft_ctx *ctx,
131 const struct nft_expr *expr)
132 {
133 struct nft_lookup *priv = nft_expr_priv(expr);
134
135 nf_tables_unbind_set(ctx, priv->set, &priv->binding);
136 }
137
nft_lookup_dump(struct sk_buff * skb,const struct nft_expr * expr)138 static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
139 {
140 const struct nft_lookup *priv = nft_expr_priv(expr);
141 u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;
142
143 if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
144 goto nla_put_failure;
145 if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
146 goto nla_put_failure;
147 if (priv->set->flags & NFT_SET_MAP)
148 if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
149 goto nla_put_failure;
150 if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
151 goto nla_put_failure;
152 return 0;
153
154 nla_put_failure:
155 return -1;
156 }
157
158 static struct nft_expr_type nft_lookup_type;
159 static const struct nft_expr_ops nft_lookup_ops = {
160 .type = &nft_lookup_type,
161 .size = NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
162 .eval = nft_lookup_eval,
163 .init = nft_lookup_init,
164 .destroy = nft_lookup_destroy,
165 .dump = nft_lookup_dump,
166 };
167
168 static struct nft_expr_type nft_lookup_type __read_mostly = {
169 .name = "lookup",
170 .ops = &nft_lookup_ops,
171 .policy = nft_lookup_policy,
172 .maxattr = NFTA_LOOKUP_MAX,
173 .owner = THIS_MODULE,
174 };
175
nft_lookup_module_init(void)176 int __init nft_lookup_module_init(void)
177 {
178 return nft_register_expr(&nft_lookup_type);
179 }
180
nft_lookup_module_exit(void)181 void nft_lookup_module_exit(void)
182 {
183 nft_unregister_expr(&nft_lookup_type);
184 }
185