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 
18 struct nft_lookup {
19 	struct nft_set			*set;
20 	u8				sreg;
21 	u8				dreg;
22 	bool				invert;
23 	struct nft_set_binding		binding;
24 };
25 
nft_lookup_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)26 void nft_lookup_eval(const struct nft_expr *expr,
27 		     struct nft_regs *regs,
28 		     const struct nft_pktinfo *pkt)
29 {
30 	const struct nft_lookup *priv = nft_expr_priv(expr);
31 	const struct nft_set *set = priv->set;
32 	const struct nft_set_ext *ext = NULL;
33 	const struct net *net = nft_net(pkt);
34 	bool found;
35 
36 	found = set->ops->lookup(net, set, &regs->data[priv->sreg], &ext) ^
37 				 priv->invert;
38 	if (!found) {
39 		ext = nft_set_catchall_lookup(net, set);
40 		if (!ext) {
41 			regs->verdict.code = NFT_BREAK;
42 			return;
43 		}
44 	}
45 
46 	if (ext) {
47 		if (set->flags & NFT_SET_MAP)
48 			nft_data_copy(&regs->data[priv->dreg],
49 				      nft_set_ext_data(ext), set->dlen);
50 
51 		nft_set_elem_update_expr(ext, regs, pkt);
52 	}
53 }
54 
55 static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
56 	[NFTA_LOOKUP_SET]	= { .type = NLA_STRING,
57 				    .len = NFT_SET_MAXNAMELEN - 1 },
58 	[NFTA_LOOKUP_SET_ID]	= { .type = NLA_U32 },
59 	[NFTA_LOOKUP_SREG]	= { .type = NLA_U32 },
60 	[NFTA_LOOKUP_DREG]	= { .type = NLA_U32 },
61 	[NFTA_LOOKUP_FLAGS]	= { .type = NLA_U32 },
62 };
63 
nft_lookup_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])64 static int nft_lookup_init(const struct nft_ctx *ctx,
65 			   const struct nft_expr *expr,
66 			   const struct nlattr * const tb[])
67 {
68 	struct nft_lookup *priv = nft_expr_priv(expr);
69 	u8 genmask = nft_genmask_next(ctx->net);
70 	struct nft_set *set;
71 	u32 flags;
72 	int err;
73 
74 	if (tb[NFTA_LOOKUP_SET] == NULL ||
75 	    tb[NFTA_LOOKUP_SREG] == NULL)
76 		return -EINVAL;
77 
78 	set = nft_set_lookup_global(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
79 				    tb[NFTA_LOOKUP_SET_ID], genmask);
80 	if (IS_ERR(set))
81 		return PTR_ERR(set);
82 
83 	err = nft_parse_register_load(tb[NFTA_LOOKUP_SREG], &priv->sreg,
84 				      set->klen);
85 	if (err < 0)
86 		return err;
87 
88 	if (tb[NFTA_LOOKUP_FLAGS]) {
89 		flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));
90 
91 		if (flags & ~NFT_LOOKUP_F_INV)
92 			return -EINVAL;
93 
94 		if (flags & NFT_LOOKUP_F_INV) {
95 			if (set->flags & NFT_SET_MAP)
96 				return -EINVAL;
97 			priv->invert = true;
98 		}
99 	}
100 
101 	if (tb[NFTA_LOOKUP_DREG] != NULL) {
102 		if (priv->invert)
103 			return -EINVAL;
104 		if (!(set->flags & NFT_SET_MAP))
105 			return -EINVAL;
106 
107 		err = nft_parse_register_store(ctx, tb[NFTA_LOOKUP_DREG],
108 					       &priv->dreg, NULL, set->dtype,
109 					       set->dlen);
110 		if (err < 0)
111 			return err;
112 	} else if (set->flags & NFT_SET_MAP)
113 		return -EINVAL;
114 
115 	priv->binding.flags = set->flags & NFT_SET_MAP;
116 
117 	err = nf_tables_bind_set(ctx, set, &priv->binding);
118 	if (err < 0)
119 		return err;
120 
121 	priv->set = set;
122 	return 0;
123 }
124 
nft_lookup_deactivate(const struct nft_ctx * ctx,const struct nft_expr * expr,enum nft_trans_phase phase)125 static void nft_lookup_deactivate(const struct nft_ctx *ctx,
126 				  const struct nft_expr *expr,
127 				  enum nft_trans_phase phase)
128 {
129 	struct nft_lookup *priv = nft_expr_priv(expr);
130 
131 	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
132 }
133 
nft_lookup_activate(const struct nft_ctx * ctx,const struct nft_expr * expr)134 static void nft_lookup_activate(const struct nft_ctx *ctx,
135 				const struct nft_expr *expr)
136 {
137 	struct nft_lookup *priv = nft_expr_priv(expr);
138 
139 	priv->set->use++;
140 }
141 
nft_lookup_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)142 static void nft_lookup_destroy(const struct nft_ctx *ctx,
143 			       const struct nft_expr *expr)
144 {
145 	struct nft_lookup *priv = nft_expr_priv(expr);
146 
147 	nf_tables_destroy_set(ctx, priv->set);
148 }
149 
nft_lookup_dump(struct sk_buff * skb,const struct nft_expr * expr)150 static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
151 {
152 	const struct nft_lookup *priv = nft_expr_priv(expr);
153 	u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;
154 
155 	if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
156 		goto nla_put_failure;
157 	if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
158 		goto nla_put_failure;
159 	if (priv->set->flags & NFT_SET_MAP)
160 		if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
161 			goto nla_put_failure;
162 	if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
163 		goto nla_put_failure;
164 	return 0;
165 
166 nla_put_failure:
167 	return -1;
168 }
169 
nft_lookup_validate_setelem(const struct nft_ctx * ctx,struct nft_set * set,const struct nft_set_iter * iter,struct nft_set_elem * elem)170 static int nft_lookup_validate_setelem(const struct nft_ctx *ctx,
171 				       struct nft_set *set,
172 				       const struct nft_set_iter *iter,
173 				       struct nft_set_elem *elem)
174 {
175 	const struct nft_set_ext *ext = nft_set_elem_ext(set, elem->priv);
176 	struct nft_ctx *pctx = (struct nft_ctx *)ctx;
177 	const struct nft_data *data;
178 	int err;
179 
180 	if (nft_set_ext_exists(ext, NFT_SET_EXT_FLAGS) &&
181 	    *nft_set_ext_flags(ext) & NFT_SET_ELEM_INTERVAL_END)
182 		return 0;
183 
184 	data = nft_set_ext_data(ext);
185 	switch (data->verdict.code) {
186 	case NFT_JUMP:
187 	case NFT_GOTO:
188 		pctx->level++;
189 		err = nft_chain_validate(ctx, data->verdict.chain);
190 		if (err < 0)
191 			return err;
192 		pctx->level--;
193 		break;
194 	default:
195 		break;
196 	}
197 
198 	return 0;
199 }
200 
nft_lookup_validate(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nft_data ** d)201 static int nft_lookup_validate(const struct nft_ctx *ctx,
202 			       const struct nft_expr *expr,
203 			       const struct nft_data **d)
204 {
205 	const struct nft_lookup *priv = nft_expr_priv(expr);
206 	struct nft_set_iter iter;
207 
208 	if (!(priv->set->flags & NFT_SET_MAP) ||
209 	    priv->set->dtype != NFT_DATA_VERDICT)
210 		return 0;
211 
212 	iter.genmask	= nft_genmask_next(ctx->net);
213 	iter.skip	= 0;
214 	iter.count	= 0;
215 	iter.err	= 0;
216 	iter.fn		= nft_lookup_validate_setelem;
217 
218 	priv->set->ops->walk(ctx, priv->set, &iter);
219 	if (iter.err < 0)
220 		return iter.err;
221 
222 	return 0;
223 }
224 
225 static const struct nft_expr_ops nft_lookup_ops = {
226 	.type		= &nft_lookup_type,
227 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
228 	.eval		= nft_lookup_eval,
229 	.init		= nft_lookup_init,
230 	.activate	= nft_lookup_activate,
231 	.deactivate	= nft_lookup_deactivate,
232 	.destroy	= nft_lookup_destroy,
233 	.dump		= nft_lookup_dump,
234 	.validate	= nft_lookup_validate,
235 };
236 
237 struct nft_expr_type nft_lookup_type __read_mostly = {
238 	.name		= "lookup",
239 	.ops		= &nft_lookup_ops,
240 	.policy		= nft_lookup_policy,
241 	.maxattr	= NFTA_LOOKUP_MAX,
242 	.owner		= THIS_MODULE,
243 };
244