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 
21 struct nft_lookup {
22 	struct nft_set			*set;
23 	enum nft_registers		sreg:8;
24 	enum nft_registers		dreg:8;
25 	bool				invert;
26 	struct nft_set_binding		binding;
27 };
28 
nft_lookup_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)29 void nft_lookup_eval(const struct nft_expr *expr,
30 		     struct nft_regs *regs,
31 		     const struct nft_pktinfo *pkt)
32 {
33 	const struct nft_lookup *priv = nft_expr_priv(expr);
34 	const struct nft_set *set = priv->set;
35 	const struct nft_set_ext *ext;
36 	bool found;
37 
38 	found = set->ops->lookup(nft_net(pkt), set, &regs->data[priv->sreg],
39 				 &ext) ^ priv->invert;
40 	if (!found) {
41 		regs->verdict.code = NFT_BREAK;
42 		return;
43 	}
44 
45 	if (set->flags & NFT_SET_MAP)
46 		nft_data_copy(&regs->data[priv->dreg],
47 			      nft_set_ext_data(ext), set->dlen);
48 
49 }
50 
51 static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
52 	[NFTA_LOOKUP_SET]	= { .type = NLA_STRING,
53 				    .len = NFT_SET_MAXNAMELEN - 1 },
54 	[NFTA_LOOKUP_SET_ID]	= { .type = NLA_U32 },
55 	[NFTA_LOOKUP_SREG]	= { .type = NLA_U32 },
56 	[NFTA_LOOKUP_DREG]	= { .type = NLA_U32 },
57 	[NFTA_LOOKUP_FLAGS]	= { .type = NLA_U32 },
58 };
59 
nft_lookup_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])60 static int nft_lookup_init(const struct nft_ctx *ctx,
61 			   const struct nft_expr *expr,
62 			   const struct nlattr * const tb[])
63 {
64 	struct nft_lookup *priv = nft_expr_priv(expr);
65 	u8 genmask = nft_genmask_next(ctx->net);
66 	struct nft_set *set;
67 	u32 flags;
68 	int err;
69 
70 	if (tb[NFTA_LOOKUP_SET] == NULL ||
71 	    tb[NFTA_LOOKUP_SREG] == NULL)
72 		return -EINVAL;
73 
74 	set = nft_set_lookup_global(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
75 				    tb[NFTA_LOOKUP_SET_ID], genmask);
76 	if (IS_ERR(set))
77 		return PTR_ERR(set);
78 
79 	if (set->flags & NFT_SET_EVAL)
80 		return -EOPNOTSUPP;
81 
82 	priv->sreg = nft_parse_register(tb[NFTA_LOOKUP_SREG]);
83 	err = nft_validate_register_load(priv->sreg, set->klen);
84 	if (err < 0)
85 		return err;
86 
87 	if (tb[NFTA_LOOKUP_FLAGS]) {
88 		flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));
89 
90 		if (flags & ~NFT_LOOKUP_F_INV)
91 			return -EINVAL;
92 
93 		if (flags & NFT_LOOKUP_F_INV) {
94 			if (set->flags & NFT_SET_MAP)
95 				return -EINVAL;
96 			priv->invert = true;
97 		}
98 	}
99 
100 	if (tb[NFTA_LOOKUP_DREG] != NULL) {
101 		if (priv->invert)
102 			return -EINVAL;
103 		if (!(set->flags & NFT_SET_MAP))
104 			return -EINVAL;
105 
106 		priv->dreg = nft_parse_register(tb[NFTA_LOOKUP_DREG]);
107 		err = nft_validate_register_store(ctx, priv->dreg, NULL,
108 						  set->dtype, set->dlen);
109 		if (err < 0)
110 			return err;
111 	} else if (set->flags & NFT_SET_MAP)
112 		return -EINVAL;
113 
114 	priv->binding.flags = set->flags & NFT_SET_MAP;
115 
116 	err = nf_tables_bind_set(ctx, set, &priv->binding);
117 	if (err < 0)
118 		return err;
119 
120 	priv->set = set;
121 	return 0;
122 }
123 
nft_lookup_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)124 static void nft_lookup_destroy(const struct nft_ctx *ctx,
125 			       const struct nft_expr *expr)
126 {
127 	struct nft_lookup *priv = nft_expr_priv(expr);
128 
129 	nf_tables_unbind_set(ctx, priv->set, &priv->binding);
130 }
131 
nft_lookup_dump(struct sk_buff * skb,const struct nft_expr * expr)132 static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
133 {
134 	const struct nft_lookup *priv = nft_expr_priv(expr);
135 	u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;
136 
137 	if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
138 		goto nla_put_failure;
139 	if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
140 		goto nla_put_failure;
141 	if (priv->set->flags & NFT_SET_MAP)
142 		if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
143 			goto nla_put_failure;
144 	if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
145 		goto nla_put_failure;
146 	return 0;
147 
148 nla_put_failure:
149 	return -1;
150 }
151 
nft_lookup_validate_setelem(const struct nft_ctx * ctx,struct nft_set * set,const struct nft_set_iter * iter,struct nft_set_elem * elem)152 static int nft_lookup_validate_setelem(const struct nft_ctx *ctx,
153 				       struct nft_set *set,
154 				       const struct nft_set_iter *iter,
155 				       struct nft_set_elem *elem)
156 {
157 	const struct nft_set_ext *ext = nft_set_elem_ext(set, elem->priv);
158 	struct nft_ctx *pctx = (struct nft_ctx *)ctx;
159 	const struct nft_data *data;
160 	int err;
161 
162 	if (nft_set_ext_exists(ext, NFT_SET_EXT_FLAGS) &&
163 	    *nft_set_ext_flags(ext) & NFT_SET_ELEM_INTERVAL_END)
164 		return 0;
165 
166 	data = nft_set_ext_data(ext);
167 	switch (data->verdict.code) {
168 	case NFT_JUMP:
169 	case NFT_GOTO:
170 		pctx->level++;
171 		err = nft_chain_validate(ctx, data->verdict.chain);
172 		if (err < 0)
173 			return err;
174 		pctx->level--;
175 		break;
176 	default:
177 		break;
178 	}
179 
180 	return 0;
181 }
182 
nft_lookup_validate(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nft_data ** d)183 static int nft_lookup_validate(const struct nft_ctx *ctx,
184 			       const struct nft_expr *expr,
185 			       const struct nft_data **d)
186 {
187 	const struct nft_lookup *priv = nft_expr_priv(expr);
188 	struct nft_set_iter iter;
189 
190 	if (!(priv->set->flags & NFT_SET_MAP) ||
191 	    priv->set->dtype != NFT_DATA_VERDICT)
192 		return 0;
193 
194 	iter.genmask	= nft_genmask_next(ctx->net);
195 	iter.skip	= 0;
196 	iter.count	= 0;
197 	iter.err	= 0;
198 	iter.fn		= nft_lookup_validate_setelem;
199 
200 	priv->set->ops->walk(ctx, priv->set, &iter);
201 	if (iter.err < 0)
202 		return iter.err;
203 
204 	return 0;
205 }
206 
207 static const struct nft_expr_ops nft_lookup_ops = {
208 	.type		= &nft_lookup_type,
209 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
210 	.eval		= nft_lookup_eval,
211 	.init		= nft_lookup_init,
212 	.destroy	= nft_lookup_destroy,
213 	.dump		= nft_lookup_dump,
214 	.validate	= nft_lookup_validate,
215 };
216 
217 struct nft_expr_type nft_lookup_type __read_mostly = {
218 	.name		= "lookup",
219 	.ops		= &nft_lookup_ops,
220 	.policy		= nft_lookup_policy,
221 	.maxattr	= NFTA_LOOKUP_MAX,
222 	.owner		= THIS_MODULE,
223 };
224