1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
4 *
5 * Development of this code funded by Astaro AG (http://www.astaro.com/)
6 */
7
8#include <linux/kernel.h>
9#include <linux/init.h>
10#include <linux/list.h>
11#include <linux/rbtree.h>
12#include <linux/netlink.h>
13#include <linux/netfilter.h>
14#include <linux/netfilter/nf_tables.h>
15#include <net/netfilter/nf_tables.h>
16#include <net/netfilter/nf_tables_core.h>
17
18struct nft_lookup {
19	struct nft_set			*set;
20	u8				sreg;
21	u8				dreg;
22	bool				dreg_set;
23	bool				invert;
24	struct nft_set_binding		binding;
25};
26
27#ifdef CONFIG_MITIGATION_RETPOLINE
28bool nft_set_do_lookup(const struct net *net, const struct nft_set *set,
29		       const u32 *key, const struct nft_set_ext **ext)
30{
31	if (set->ops == &nft_set_hash_fast_type.ops)
32		return nft_hash_lookup_fast(net, set, key, ext);
33	if (set->ops == &nft_set_hash_type.ops)
34		return nft_hash_lookup(net, set, key, ext);
35
36	if (set->ops == &nft_set_rhash_type.ops)
37		return nft_rhash_lookup(net, set, key, ext);
38
39	if (set->ops == &nft_set_bitmap_type.ops)
40		return nft_bitmap_lookup(net, set, key, ext);
41
42	if (set->ops == &nft_set_pipapo_type.ops)
43		return nft_pipapo_lookup(net, set, key, ext);
44#if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
45	if (set->ops == &nft_set_pipapo_avx2_type.ops)
46		return nft_pipapo_avx2_lookup(net, set, key, ext);
47#endif
48
49	if (set->ops == &nft_set_rbtree_type.ops)
50		return nft_rbtree_lookup(net, set, key, ext);
51
52	WARN_ON_ONCE(1);
53	return set->ops->lookup(net, set, key, ext);
54}
55EXPORT_SYMBOL_GPL(nft_set_do_lookup);
56#endif
57
58void nft_lookup_eval(const struct nft_expr *expr,
59		     struct nft_regs *regs,
60		     const struct nft_pktinfo *pkt)
61{
62	const struct nft_lookup *priv = nft_expr_priv(expr);
63	const struct nft_set *set = priv->set;
64	const struct nft_set_ext *ext = NULL;
65	const struct net *net = nft_net(pkt);
66	bool found;
67
68	found =	nft_set_do_lookup(net, set, &regs->data[priv->sreg], &ext) ^
69				  priv->invert;
70	if (!found) {
71		ext = nft_set_catchall_lookup(net, set);
72		if (!ext) {
73			regs->verdict.code = NFT_BREAK;
74			return;
75		}
76	}
77
78	if (ext) {
79		if (priv->dreg_set)
80			nft_data_copy(&regs->data[priv->dreg],
81				      nft_set_ext_data(ext), set->dlen);
82
83		nft_set_elem_update_expr(ext, regs, pkt);
84	}
85}
86
87static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
88	[NFTA_LOOKUP_SET]	= { .type = NLA_STRING,
89				    .len = NFT_SET_MAXNAMELEN - 1 },
90	[NFTA_LOOKUP_SET_ID]	= { .type = NLA_U32 },
91	[NFTA_LOOKUP_SREG]	= { .type = NLA_U32 },
92	[NFTA_LOOKUP_DREG]	= { .type = NLA_U32 },
93	[NFTA_LOOKUP_FLAGS]	=
94		NLA_POLICY_MASK(NLA_BE32, NFT_LOOKUP_F_INV),
95};
96
97static int nft_lookup_init(const struct nft_ctx *ctx,
98			   const struct nft_expr *expr,
99			   const struct nlattr * const tb[])
100{
101	struct nft_lookup *priv = nft_expr_priv(expr);
102	u8 genmask = nft_genmask_next(ctx->net);
103	struct nft_set *set;
104	u32 flags;
105	int err;
106
107	if (tb[NFTA_LOOKUP_SET] == NULL ||
108	    tb[NFTA_LOOKUP_SREG] == NULL)
109		return -EINVAL;
110
111	set = nft_set_lookup_global(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
112				    tb[NFTA_LOOKUP_SET_ID], genmask);
113	if (IS_ERR(set))
114		return PTR_ERR(set);
115
116	err = nft_parse_register_load(tb[NFTA_LOOKUP_SREG], &priv->sreg,
117				      set->klen);
118	if (err < 0)
119		return err;
120
121	if (tb[NFTA_LOOKUP_FLAGS]) {
122		flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));
123
124		if (flags & NFT_LOOKUP_F_INV)
125			priv->invert = true;
126	}
127
128	if (tb[NFTA_LOOKUP_DREG] != NULL) {
129		if (priv->invert)
130			return -EINVAL;
131		if (!(set->flags & NFT_SET_MAP))
132			return -EINVAL;
133
134		err = nft_parse_register_store(ctx, tb[NFTA_LOOKUP_DREG],
135					       &priv->dreg, NULL, set->dtype,
136					       set->dlen);
137		if (err < 0)
138			return err;
139		priv->dreg_set = true;
140	} else if (set->flags & NFT_SET_MAP) {
141		/* Map given, but user asks for lookup only (i.e. to
142		 * ignore value assoicated with key).
143		 *
144		 * This makes no sense for anonymous maps since they are
145		 * scoped to the rule, but for named sets this can be useful.
146		 */
147		if (set->flags & NFT_SET_ANONYMOUS)
148			return -EINVAL;
149	}
150
151	priv->binding.flags = set->flags & NFT_SET_MAP;
152
153	err = nf_tables_bind_set(ctx, set, &priv->binding);
154	if (err < 0)
155		return err;
156
157	priv->set = set;
158	return 0;
159}
160
161static void nft_lookup_deactivate(const struct nft_ctx *ctx,
162				  const struct nft_expr *expr,
163				  enum nft_trans_phase phase)
164{
165	struct nft_lookup *priv = nft_expr_priv(expr);
166
167	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
168}
169
170static void nft_lookup_activate(const struct nft_ctx *ctx,
171				const struct nft_expr *expr)
172{
173	struct nft_lookup *priv = nft_expr_priv(expr);
174
175	nf_tables_activate_set(ctx, priv->set);
176}
177
178static void nft_lookup_destroy(const struct nft_ctx *ctx,
179			       const struct nft_expr *expr)
180{
181	struct nft_lookup *priv = nft_expr_priv(expr);
182
183	nf_tables_destroy_set(ctx, priv->set);
184}
185
186static int nft_lookup_dump(struct sk_buff *skb,
187			   const struct nft_expr *expr, bool reset)
188{
189	const struct nft_lookup *priv = nft_expr_priv(expr);
190	u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;
191
192	if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
193		goto nla_put_failure;
194	if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
195		goto nla_put_failure;
196	if (priv->dreg_set)
197		if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
198			goto nla_put_failure;
199	if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
200		goto nla_put_failure;
201	return 0;
202
203nla_put_failure:
204	return -1;
205}
206
207static int nft_lookup_validate(const struct nft_ctx *ctx,
208			       const struct nft_expr *expr,
209			       const struct nft_data **d)
210{
211	const struct nft_lookup *priv = nft_expr_priv(expr);
212	struct nft_set_iter iter;
213
214	if (!(priv->set->flags & NFT_SET_MAP) ||
215	    priv->set->dtype != NFT_DATA_VERDICT)
216		return 0;
217
218	iter.genmask	= nft_genmask_next(ctx->net);
219	iter.type	= NFT_ITER_UPDATE;
220	iter.skip	= 0;
221	iter.count	= 0;
222	iter.err	= 0;
223	iter.fn		= nft_setelem_validate;
224
225	priv->set->ops->walk(ctx, priv->set, &iter);
226	if (!iter.err)
227		iter.err = nft_set_catchall_validate(ctx, priv->set);
228
229	if (iter.err < 0)
230		return iter.err;
231
232	return 0;
233}
234
235static bool nft_lookup_reduce(struct nft_regs_track *track,
236			      const struct nft_expr *expr)
237{
238	const struct nft_lookup *priv = nft_expr_priv(expr);
239
240	if (priv->set->flags & NFT_SET_MAP)
241		nft_reg_track_cancel(track, priv->dreg, priv->set->dlen);
242
243	return false;
244}
245
246static const struct nft_expr_ops nft_lookup_ops = {
247	.type		= &nft_lookup_type,
248	.size		= NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
249	.eval		= nft_lookup_eval,
250	.init		= nft_lookup_init,
251	.activate	= nft_lookup_activate,
252	.deactivate	= nft_lookup_deactivate,
253	.destroy	= nft_lookup_destroy,
254	.dump		= nft_lookup_dump,
255	.validate	= nft_lookup_validate,
256	.reduce		= nft_lookup_reduce,
257};
258
259struct nft_expr_type nft_lookup_type __read_mostly = {
260	.name		= "lookup",
261	.ops		= &nft_lookup_ops,
262	.policy		= nft_lookup_policy,
263	.maxattr	= NFTA_LOOKUP_MAX,
264	.owner		= THIS_MODULE,
265};
266