1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
4 */
5
6 #include <linux/kernel.h>
7 #include <linux/init.h>
8 #include <linux/module.h>
9 #include <linux/netlink.h>
10 #include <linux/netfilter.h>
11 #include <linux/netfilter/nf_tables.h>
12 #include <net/netfilter/nf_tables_core.h>
13 #include <net/netfilter/nf_tables.h>
14
15 struct nft_range_expr {
16 struct nft_data data_from;
17 struct nft_data data_to;
18 u8 sreg;
19 u8 len;
20 enum nft_range_ops op:8;
21 };
22
nft_range_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)23 void nft_range_eval(const struct nft_expr *expr,
24 struct nft_regs *regs, const struct nft_pktinfo *pkt)
25 {
26 const struct nft_range_expr *priv = nft_expr_priv(expr);
27 int d1, d2;
28
29 d1 = memcmp(®s->data[priv->sreg], &priv->data_from, priv->len);
30 d2 = memcmp(®s->data[priv->sreg], &priv->data_to, priv->len);
31 switch (priv->op) {
32 case NFT_RANGE_EQ:
33 if (d1 < 0 || d2 > 0)
34 regs->verdict.code = NFT_BREAK;
35 break;
36 case NFT_RANGE_NEQ:
37 if (d1 >= 0 && d2 <= 0)
38 regs->verdict.code = NFT_BREAK;
39 break;
40 }
41 }
42
43 static const struct nla_policy nft_range_policy[NFTA_RANGE_MAX + 1] = {
44 [NFTA_RANGE_SREG] = { .type = NLA_U32 },
45 [NFTA_RANGE_OP] = { .type = NLA_U32 },
46 [NFTA_RANGE_FROM_DATA] = { .type = NLA_NESTED },
47 [NFTA_RANGE_TO_DATA] = { .type = NLA_NESTED },
48 };
49
nft_range_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])50 static int nft_range_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
51 const struct nlattr * const tb[])
52 {
53 struct nft_range_expr *priv = nft_expr_priv(expr);
54 struct nft_data_desc desc_from, desc_to;
55 int err;
56 u32 op;
57
58 if (!tb[NFTA_RANGE_SREG] ||
59 !tb[NFTA_RANGE_OP] ||
60 !tb[NFTA_RANGE_FROM_DATA] ||
61 !tb[NFTA_RANGE_TO_DATA])
62 return -EINVAL;
63
64 err = nft_data_init(NULL, &priv->data_from, sizeof(priv->data_from),
65 &desc_from, tb[NFTA_RANGE_FROM_DATA]);
66 if (err < 0)
67 return err;
68
69 if (desc_from.type != NFT_DATA_VALUE) {
70 err = -EINVAL;
71 goto err1;
72 }
73
74 err = nft_data_init(NULL, &priv->data_to, sizeof(priv->data_to),
75 &desc_to, tb[NFTA_RANGE_TO_DATA]);
76 if (err < 0)
77 goto err1;
78
79 if (desc_to.type != NFT_DATA_VALUE) {
80 err = -EINVAL;
81 goto err2;
82 }
83
84 if (desc_from.len != desc_to.len) {
85 err = -EINVAL;
86 goto err2;
87 }
88
89 err = nft_parse_register_load(tb[NFTA_RANGE_SREG], &priv->sreg,
90 desc_from.len);
91 if (err < 0)
92 goto err2;
93
94 err = nft_parse_u32_check(tb[NFTA_RANGE_OP], U8_MAX, &op);
95 if (err < 0)
96 goto err2;
97
98 switch (op) {
99 case NFT_RANGE_EQ:
100 case NFT_RANGE_NEQ:
101 break;
102 default:
103 err = -EINVAL;
104 goto err2;
105 }
106
107 priv->op = op;
108 priv->len = desc_from.len;
109 return 0;
110 err2:
111 nft_data_release(&priv->data_to, desc_to.type);
112 err1:
113 nft_data_release(&priv->data_from, desc_from.type);
114 return err;
115 }
116
nft_range_dump(struct sk_buff * skb,const struct nft_expr * expr)117 static int nft_range_dump(struct sk_buff *skb, const struct nft_expr *expr)
118 {
119 const struct nft_range_expr *priv = nft_expr_priv(expr);
120
121 if (nft_dump_register(skb, NFTA_RANGE_SREG, priv->sreg))
122 goto nla_put_failure;
123 if (nla_put_be32(skb, NFTA_RANGE_OP, htonl(priv->op)))
124 goto nla_put_failure;
125
126 if (nft_data_dump(skb, NFTA_RANGE_FROM_DATA, &priv->data_from,
127 NFT_DATA_VALUE, priv->len) < 0 ||
128 nft_data_dump(skb, NFTA_RANGE_TO_DATA, &priv->data_to,
129 NFT_DATA_VALUE, priv->len) < 0)
130 goto nla_put_failure;
131 return 0;
132
133 nla_put_failure:
134 return -1;
135 }
136
137 static const struct nft_expr_ops nft_range_ops = {
138 .type = &nft_range_type,
139 .size = NFT_EXPR_SIZE(sizeof(struct nft_range_expr)),
140 .eval = nft_range_eval,
141 .init = nft_range_init,
142 .dump = nft_range_dump,
143 };
144
145 struct nft_expr_type nft_range_type __read_mostly = {
146 .name = "range",
147 .ops = &nft_range_ops,
148 .policy = nft_range_policy,
149 .maxattr = NFTA_RANGE_MAX,
150 .owner = THIS_MODULE,
151 };
152