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]			= { .type = NLA_U32 },
 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, 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;
110err2:
111	nft_data_release(&priv->data_to, desc_to.type);
112err1:
113	nft_data_release(&priv->data_from, desc_from.type);
114	return err;
115}
116
117static 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
133nla_put_failure:
134	return -1;
135}
136
137static 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
145struct 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};