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
21struct nft_lookup {
22	struct nft_set			*set;
23	enum nft_registers		sreg:8;
24	enum nft_registers		dreg:8;
25	struct nft_set_binding		binding;
26};
27
28static void nft_lookup_eval(const struct nft_expr *expr,
29			    struct nft_regs *regs,
30			    const struct nft_pktinfo *pkt)
31{
32	const struct nft_lookup *priv = nft_expr_priv(expr);
33	const struct nft_set *set = priv->set;
34	const struct nft_set_ext *ext;
35
36	if (set->ops->lookup(set, &regs->data[priv->sreg], &ext)) {
37		if (set->flags & NFT_SET_MAP)
38			nft_data_copy(&regs->data[priv->dreg],
39				      nft_set_ext_data(ext), set->dlen);
40		return;
41	}
42	regs->verdict.code = NFT_BREAK;
43}
44
45static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
46	[NFTA_LOOKUP_SET]	= { .type = NLA_STRING },
47	[NFTA_LOOKUP_SET_ID]	= { .type = NLA_U32 },
48	[NFTA_LOOKUP_SREG]	= { .type = NLA_U32 },
49	[NFTA_LOOKUP_DREG]	= { .type = NLA_U32 },
50};
51
52static int nft_lookup_init(const struct nft_ctx *ctx,
53			   const struct nft_expr *expr,
54			   const struct nlattr * const tb[])
55{
56	struct nft_lookup *priv = nft_expr_priv(expr);
57	struct nft_set *set;
58	int err;
59
60	if (tb[NFTA_LOOKUP_SET] == NULL ||
61	    tb[NFTA_LOOKUP_SREG] == NULL)
62		return -EINVAL;
63
64	set = nf_tables_set_lookup(ctx->table, tb[NFTA_LOOKUP_SET]);
65	if (IS_ERR(set)) {
66		if (tb[NFTA_LOOKUP_SET_ID]) {
67			set = nf_tables_set_lookup_byid(ctx->net,
68							tb[NFTA_LOOKUP_SET_ID]);
69		}
70		if (IS_ERR(set))
71			return PTR_ERR(set);
72	}
73
74	if (set->flags & NFT_SET_EVAL)
75		return -EOPNOTSUPP;
76
77	priv->sreg = nft_parse_register(tb[NFTA_LOOKUP_SREG]);
78	err = nft_validate_register_load(priv->sreg, set->klen);
79	if (err < 0)
80		return err;
81
82	if (tb[NFTA_LOOKUP_DREG] != NULL) {
83		if (!(set->flags & NFT_SET_MAP))
84			return -EINVAL;
85
86		priv->dreg = nft_parse_register(tb[NFTA_LOOKUP_DREG]);
87		err = nft_validate_register_store(ctx, priv->dreg, NULL,
88						  set->dtype, set->dlen);
89		if (err < 0)
90			return err;
91	} else if (set->flags & NFT_SET_MAP)
92		return -EINVAL;
93
94	priv->binding.flags = set->flags & NFT_SET_MAP;
95
96	err = nf_tables_bind_set(ctx, set, &priv->binding);
97	if (err < 0)
98		return err;
99
100	priv->set = set;
101	return 0;
102}
103
104static void nft_lookup_destroy(const struct nft_ctx *ctx,
105			       const struct nft_expr *expr)
106{
107	struct nft_lookup *priv = nft_expr_priv(expr);
108
109	nf_tables_unbind_set(ctx, priv->set, &priv->binding);
110}
111
112static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
113{
114	const struct nft_lookup *priv = nft_expr_priv(expr);
115
116	if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
117		goto nla_put_failure;
118	if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
119		goto nla_put_failure;
120	if (priv->set->flags & NFT_SET_MAP)
121		if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
122			goto nla_put_failure;
123	return 0;
124
125nla_put_failure:
126	return -1;
127}
128
129static struct nft_expr_type nft_lookup_type;
130static const struct nft_expr_ops nft_lookup_ops = {
131	.type		= &nft_lookup_type,
132	.size		= NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
133	.eval		= nft_lookup_eval,
134	.init		= nft_lookup_init,
135	.destroy	= nft_lookup_destroy,
136	.dump		= nft_lookup_dump,
137};
138
139static struct nft_expr_type nft_lookup_type __read_mostly = {
140	.name		= "lookup",
141	.ops		= &nft_lookup_ops,
142	.policy		= nft_lookup_policy,
143	.maxattr	= NFTA_LOOKUP_MAX,
144	.owner		= THIS_MODULE,
145};
146
147int __init nft_lookup_module_init(void)
148{
149	return nft_register_expr(&nft_lookup_type);
150}
151
152void nft_lookup_module_exit(void)
153{
154	nft_unregister_expr(&nft_lookup_type);
155}
156