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
15struct 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
23void 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(&regs->data[priv->sreg], &priv->data_from, priv->len);
30	d2 = memcmp(&regs->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
43static const struct nla_policy nft_range_policy[NFTA_RANGE_MAX + 1] = {
44	[NFTA_RANGE_SREG]		= { .type = NLA_U32 },
45	[NFTA_RANGE_OP]			= NLA_POLICY_MAX(NLA_BE32, 255),
46	[NFTA_RANGE_FROM_DATA]		= { .type = NLA_NESTED },
47	[NFTA_RANGE_TO_DATA]		= { .type = NLA_NESTED },
48};
49
50static 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 = {
55		.type	= NFT_DATA_VALUE,
56		.size	= sizeof(priv->data_from),
57	};
58	struct nft_data_desc desc_to = {
59		.type	= NFT_DATA_VALUE,
60		.size	= sizeof(priv->data_to),
61	};
62	int err;
63	u32 op;
64
65	if (!tb[NFTA_RANGE_SREG]      ||
66	    !tb[NFTA_RANGE_OP]	      ||
67	    !tb[NFTA_RANGE_FROM_DATA] ||
68	    !tb[NFTA_RANGE_TO_DATA])
69		return -EINVAL;
70
71	err = nft_data_init(NULL, &priv->data_from, &desc_from,
72			    tb[NFTA_RANGE_FROM_DATA]);
73	if (err < 0)
74		return err;
75
76	err = nft_data_init(NULL, &priv->data_to, &desc_to,
77			    tb[NFTA_RANGE_TO_DATA]);
78	if (err < 0)
79		goto err1;
80
81	if (desc_from.len != desc_to.len) {
82		err = -EINVAL;
83		goto err2;
84	}
85
86	err = nft_parse_register_load(tb[NFTA_RANGE_SREG], &priv->sreg,
87				      desc_from.len);
88	if (err < 0)
89		goto err2;
90
91	err = nft_parse_u32_check(tb[NFTA_RANGE_OP], U8_MAX, &op);
92	if (err < 0)
93		goto err2;
94
95	switch (op) {
96	case NFT_RANGE_EQ:
97	case NFT_RANGE_NEQ:
98		break;
99	default:
100		err = -EINVAL;
101		goto err2;
102	}
103
104	priv->op  = op;
105	priv->len = desc_from.len;
106	return 0;
107err2:
108	nft_data_release(&priv->data_to, desc_to.type);
109err1:
110	nft_data_release(&priv->data_from, desc_from.type);
111	return err;
112}
113
114static int nft_range_dump(struct sk_buff *skb,
115			  const struct nft_expr *expr, bool reset)
116{
117	const struct nft_range_expr *priv = nft_expr_priv(expr);
118
119	if (nft_dump_register(skb, NFTA_RANGE_SREG, priv->sreg))
120		goto nla_put_failure;
121	if (nla_put_be32(skb, NFTA_RANGE_OP, htonl(priv->op)))
122		goto nla_put_failure;
123
124	if (nft_data_dump(skb, NFTA_RANGE_FROM_DATA, &priv->data_from,
125			  NFT_DATA_VALUE, priv->len) < 0 ||
126	    nft_data_dump(skb, NFTA_RANGE_TO_DATA, &priv->data_to,
127			  NFT_DATA_VALUE, priv->len) < 0)
128		goto nla_put_failure;
129	return 0;
130
131nla_put_failure:
132	return -1;
133}
134
135static const struct nft_expr_ops nft_range_ops = {
136	.type		= &nft_range_type,
137	.size		= NFT_EXPR_SIZE(sizeof(struct nft_range_expr)),
138	.eval		= nft_range_eval,
139	.init		= nft_range_init,
140	.dump		= nft_range_dump,
141	.reduce		= NFT_REDUCE_READONLY,
142};
143
144struct nft_expr_type nft_range_type __read_mostly = {
145	.name		= "range",
146	.ops		= &nft_range_ops,
147	.policy		= nft_range_policy,
148	.maxattr	= NFTA_RANGE_MAX,
149	.owner		= THIS_MODULE,
150};
151