1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2012-2016 Pablo Neira Ayuso <pablo@netfilter.org>
4 */
5
6#include <linux/init.h>
7#include <linux/module.h>
8#include <linux/skbuff.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
14#define nft_objref_priv(expr)	*((struct nft_object **)nft_expr_priv(expr))
15
16void nft_objref_eval(const struct nft_expr *expr,
17		     struct nft_regs *regs,
18		     const struct nft_pktinfo *pkt)
19{
20	struct nft_object *obj = nft_objref_priv(expr);
21
22	obj->ops->eval(obj, regs, pkt);
23}
24
25static int nft_objref_init(const struct nft_ctx *ctx,
26			   const struct nft_expr *expr,
27			   const struct nlattr * const tb[])
28{
29	struct nft_object *obj = nft_objref_priv(expr);
30	u8 genmask = nft_genmask_next(ctx->net);
31	u32 objtype;
32
33	if (!tb[NFTA_OBJREF_IMM_NAME] ||
34	    !tb[NFTA_OBJREF_IMM_TYPE])
35		return -EINVAL;
36
37	objtype = ntohl(nla_get_be32(tb[NFTA_OBJREF_IMM_TYPE]));
38	obj = nft_obj_lookup(ctx->net, ctx->table,
39			     tb[NFTA_OBJREF_IMM_NAME], objtype,
40			     genmask);
41	if (IS_ERR(obj))
42		return -ENOENT;
43
44	if (!nft_use_inc(&obj->use))
45		return -EMFILE;
46
47	nft_objref_priv(expr) = obj;
48
49	return 0;
50}
51
52static int nft_objref_dump(struct sk_buff *skb,
53			   const struct nft_expr *expr, bool reset)
54{
55	const struct nft_object *obj = nft_objref_priv(expr);
56
57	if (nla_put_string(skb, NFTA_OBJREF_IMM_NAME, obj->key.name) ||
58	    nla_put_be32(skb, NFTA_OBJREF_IMM_TYPE,
59			 htonl(obj->ops->type->type)))
60		goto nla_put_failure;
61
62	return 0;
63
64nla_put_failure:
65	return -1;
66}
67
68static void nft_objref_deactivate(const struct nft_ctx *ctx,
69				  const struct nft_expr *expr,
70				  enum nft_trans_phase phase)
71{
72	struct nft_object *obj = nft_objref_priv(expr);
73
74	if (phase == NFT_TRANS_COMMIT)
75		return;
76
77	nft_use_dec(&obj->use);
78}
79
80static void nft_objref_activate(const struct nft_ctx *ctx,
81				const struct nft_expr *expr)
82{
83	struct nft_object *obj = nft_objref_priv(expr);
84
85	nft_use_inc_restore(&obj->use);
86}
87
88static const struct nft_expr_ops nft_objref_ops = {
89	.type		= &nft_objref_type,
90	.size		= NFT_EXPR_SIZE(sizeof(struct nft_object *)),
91	.eval		= nft_objref_eval,
92	.init		= nft_objref_init,
93	.activate	= nft_objref_activate,
94	.deactivate	= nft_objref_deactivate,
95	.dump		= nft_objref_dump,
96	.reduce		= NFT_REDUCE_READONLY,
97};
98
99struct nft_objref_map {
100	struct nft_set		*set;
101	u8			sreg;
102	struct nft_set_binding	binding;
103};
104
105void nft_objref_map_eval(const struct nft_expr *expr,
106			 struct nft_regs *regs,
107			 const struct nft_pktinfo *pkt)
108{
109	struct nft_objref_map *priv = nft_expr_priv(expr);
110	const struct nft_set *set = priv->set;
111	struct net *net = nft_net(pkt);
112	const struct nft_set_ext *ext;
113	struct nft_object *obj;
114	bool found;
115
116	found = nft_set_do_lookup(net, set, &regs->data[priv->sreg], &ext);
117	if (!found) {
118		ext = nft_set_catchall_lookup(net, set);
119		if (!ext) {
120			regs->verdict.code = NFT_BREAK;
121			return;
122		}
123	}
124	obj = *nft_set_ext_obj(ext);
125	obj->ops->eval(obj, regs, pkt);
126}
127
128static int nft_objref_map_init(const struct nft_ctx *ctx,
129			       const struct nft_expr *expr,
130			       const struct nlattr * const tb[])
131{
132	struct nft_objref_map *priv = nft_expr_priv(expr);
133	u8 genmask = nft_genmask_next(ctx->net);
134	struct nft_set *set;
135	int err;
136
137	set = nft_set_lookup_global(ctx->net, ctx->table,
138				    tb[NFTA_OBJREF_SET_NAME],
139				    tb[NFTA_OBJREF_SET_ID], genmask);
140	if (IS_ERR(set))
141		return PTR_ERR(set);
142
143	if (!(set->flags & NFT_SET_OBJECT))
144		return -EINVAL;
145
146	err = nft_parse_register_load(tb[NFTA_OBJREF_SET_SREG], &priv->sreg,
147				      set->klen);
148	if (err < 0)
149		return err;
150
151	priv->binding.flags = set->flags & NFT_SET_OBJECT;
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 int nft_objref_map_dump(struct sk_buff *skb,
162			       const struct nft_expr *expr, bool reset)
163{
164	const struct nft_objref_map *priv = nft_expr_priv(expr);
165
166	if (nft_dump_register(skb, NFTA_OBJREF_SET_SREG, priv->sreg) ||
167	    nla_put_string(skb, NFTA_OBJREF_SET_NAME, priv->set->name))
168		goto nla_put_failure;
169
170	return 0;
171
172nla_put_failure:
173	return -1;
174}
175
176static void nft_objref_map_deactivate(const struct nft_ctx *ctx,
177				      const struct nft_expr *expr,
178				      enum nft_trans_phase phase)
179{
180	struct nft_objref_map *priv = nft_expr_priv(expr);
181
182	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
183}
184
185static void nft_objref_map_activate(const struct nft_ctx *ctx,
186				    const struct nft_expr *expr)
187{
188	struct nft_objref_map *priv = nft_expr_priv(expr);
189
190	nf_tables_activate_set(ctx, priv->set);
191}
192
193static void nft_objref_map_destroy(const struct nft_ctx *ctx,
194				   const struct nft_expr *expr)
195{
196	struct nft_objref_map *priv = nft_expr_priv(expr);
197
198	nf_tables_destroy_set(ctx, priv->set);
199}
200
201static const struct nft_expr_ops nft_objref_map_ops = {
202	.type		= &nft_objref_type,
203	.size		= NFT_EXPR_SIZE(sizeof(struct nft_objref_map)),
204	.eval		= nft_objref_map_eval,
205	.init		= nft_objref_map_init,
206	.activate	= nft_objref_map_activate,
207	.deactivate	= nft_objref_map_deactivate,
208	.destroy	= nft_objref_map_destroy,
209	.dump		= nft_objref_map_dump,
210	.reduce		= NFT_REDUCE_READONLY,
211};
212
213static const struct nft_expr_ops *
214nft_objref_select_ops(const struct nft_ctx *ctx,
215                      const struct nlattr * const tb[])
216{
217	if (tb[NFTA_OBJREF_SET_SREG] &&
218	    (tb[NFTA_OBJREF_SET_NAME] ||
219	     tb[NFTA_OBJREF_SET_ID]))
220		return &nft_objref_map_ops;
221	else if (tb[NFTA_OBJREF_IMM_NAME] &&
222		 tb[NFTA_OBJREF_IMM_TYPE])
223		return &nft_objref_ops;
224
225	return ERR_PTR(-EOPNOTSUPP);
226}
227
228static const struct nla_policy nft_objref_policy[NFTA_OBJREF_MAX + 1] = {
229	[NFTA_OBJREF_IMM_NAME]	= { .type = NLA_STRING,
230				    .len = NFT_OBJ_MAXNAMELEN - 1 },
231	[NFTA_OBJREF_IMM_TYPE]	= { .type = NLA_U32 },
232	[NFTA_OBJREF_SET_SREG]	= { .type = NLA_U32 },
233	[NFTA_OBJREF_SET_NAME]	= { .type = NLA_STRING,
234				    .len = NFT_SET_MAXNAMELEN - 1 },
235	[NFTA_OBJREF_SET_ID]	= { .type = NLA_U32 },
236};
237
238struct nft_expr_type nft_objref_type __read_mostly = {
239	.name		= "objref",
240	.select_ops	= nft_objref_select_ops,
241	.policy		= nft_objref_policy,
242	.maxattr	= NFTA_OBJREF_MAX,
243	.owner		= THIS_MODULE,
244};
245