1 /*
2 * Copyright (c) 2015 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 */
9
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/netlink.h>
14 #include <linux/netfilter.h>
15 #include <linux/netfilter/nf_tables.h>
16 #include <net/netfilter/nf_tables.h>
17 #include <net/netfilter/nf_tables_core.h>
18
19 struct nft_dynset {
20 struct nft_set *set;
21 struct nft_set_ext_tmpl tmpl;
22 enum nft_dynset_ops op:8;
23 enum nft_registers sreg_key:8;
24 enum nft_registers sreg_data:8;
25 u64 timeout;
26 struct nft_expr *expr;
27 struct nft_set_binding binding;
28 };
29
30 static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr,
31 struct nft_regs *regs)
32 {
33 const struct nft_dynset *priv = nft_expr_priv(expr);
34 struct nft_set_ext *ext;
35 u64 timeout;
36 void *elem;
37
38 if (set->size && !atomic_add_unless(&set->nelems, 1, set->size))
39 return NULL;
40
41 timeout = priv->timeout ? : set->timeout;
42 elem = nft_set_elem_init(set, &priv->tmpl,
43 ®s->data[priv->sreg_key],
44 ®s->data[priv->sreg_data],
45 timeout, GFP_ATOMIC);
46 if (elem == NULL) {
47 if (set->size)
48 atomic_dec(&set->nelems);
49 return NULL;
50 }
51
52 ext = nft_set_elem_ext(set, elem);
53 if (priv->expr != NULL &&
54 nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0)
55 return NULL;
56
57 return elem;
58 }
59
60 static void nft_dynset_eval(const struct nft_expr *expr,
61 struct nft_regs *regs,
62 const struct nft_pktinfo *pkt)
63 {
64 const struct nft_dynset *priv = nft_expr_priv(expr);
65 struct nft_set *set = priv->set;
66 const struct nft_set_ext *ext;
67 const struct nft_expr *sexpr;
68 u64 timeout;
69
70 if (set->ops->update(set, ®s->data[priv->sreg_key], nft_dynset_new,
71 expr, regs, &ext)) {
72 sexpr = NULL;
73 if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR))
74 sexpr = nft_set_ext_expr(ext);
75
76 if (priv->op == NFT_DYNSET_OP_UPDATE &&
77 nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
78 timeout = priv->timeout ? : set->timeout;
79 *nft_set_ext_expiration(ext) = jiffies + timeout;
80 } else if (sexpr == NULL)
81 goto out;
82
83 if (sexpr != NULL)
84 sexpr->ops->eval(sexpr, regs, pkt);
85 return;
86 }
87 out:
88 regs->verdict.code = NFT_BREAK;
89 }
90
91 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
92 [NFTA_DYNSET_SET_NAME] = { .type = NLA_STRING },
93 [NFTA_DYNSET_SET_ID] = { .type = NLA_U32 },
94 [NFTA_DYNSET_OP] = { .type = NLA_U32 },
95 [NFTA_DYNSET_SREG_KEY] = { .type = NLA_U32 },
96 [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 },
97 [NFTA_DYNSET_TIMEOUT] = { .type = NLA_U64 },
98 [NFTA_DYNSET_EXPR] = { .type = NLA_NESTED },
99 };
100
101 static int nft_dynset_init(const struct nft_ctx *ctx,
102 const struct nft_expr *expr,
103 const struct nlattr * const tb[])
104 {
105 struct nft_dynset *priv = nft_expr_priv(expr);
106 u8 genmask = nft_genmask_next(ctx->net);
107 struct nft_set *set;
108 u64 timeout;
109 int err;
110
111 if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
112 tb[NFTA_DYNSET_OP] == NULL ||
113 tb[NFTA_DYNSET_SREG_KEY] == NULL)
114 return -EINVAL;
115
116 set = nf_tables_set_lookup(ctx->table, tb[NFTA_DYNSET_SET_NAME],
117 genmask);
118 if (IS_ERR(set)) {
119 if (tb[NFTA_DYNSET_SET_ID])
120 set = nf_tables_set_lookup_byid(ctx->net,
121 tb[NFTA_DYNSET_SET_ID],
122 genmask);
123 if (IS_ERR(set))
124 return PTR_ERR(set);
125 }
126
127 if (set->flags & NFT_SET_CONSTANT)
128 return -EBUSY;
129
130 priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
131 switch (priv->op) {
132 case NFT_DYNSET_OP_ADD:
133 break;
134 case NFT_DYNSET_OP_UPDATE:
135 if (!(set->flags & NFT_SET_TIMEOUT))
136 return -EOPNOTSUPP;
137 break;
138 default:
139 return -EOPNOTSUPP;
140 }
141
142 timeout = 0;
143 if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
144 if (!(set->flags & NFT_SET_TIMEOUT))
145 return -EINVAL;
146 timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64(
147 tb[NFTA_DYNSET_TIMEOUT])));
148 }
149
150 priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]);
151 err = nft_validate_register_load(priv->sreg_key, set->klen);;
152 if (err < 0)
153 return err;
154
155 if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
156 if (!(set->flags & NFT_SET_MAP))
157 return -EINVAL;
158 if (set->dtype == NFT_DATA_VERDICT)
159 return -EOPNOTSUPP;
160
161 priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]);
162 err = nft_validate_register_load(priv->sreg_data, set->dlen);
163 if (err < 0)
164 return err;
165 } else if (set->flags & NFT_SET_MAP)
166 return -EINVAL;
167
168 if (tb[NFTA_DYNSET_EXPR] != NULL) {
169 if (!(set->flags & NFT_SET_EVAL))
170 return -EINVAL;
171 if (!(set->flags & NFT_SET_ANONYMOUS))
172 return -EOPNOTSUPP;
173
174 priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]);
175 if (IS_ERR(priv->expr))
176 return PTR_ERR(priv->expr);
177
178 err = -EOPNOTSUPP;
179 if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL))
180 goto err1;
181 } else if (set->flags & NFT_SET_EVAL)
182 return -EINVAL;
183
184 nft_set_ext_prepare(&priv->tmpl);
185 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
186 if (set->flags & NFT_SET_MAP)
187 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);
188 if (priv->expr != NULL)
189 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR,
190 priv->expr->ops->size);
191 if (set->flags & NFT_SET_TIMEOUT) {
192 if (timeout || set->timeout)
193 nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
194 }
195
196 priv->timeout = timeout;
197
198 err = nf_tables_bind_set(ctx, set, &priv->binding);
199 if (err < 0)
200 goto err1;
201
202 priv->set = set;
203 return 0;
204
205 err1:
206 if (priv->expr != NULL)
207 nft_expr_destroy(ctx, priv->expr);
208 return err;
209 }
210
211 static void nft_dynset_destroy(const struct nft_ctx *ctx,
212 const struct nft_expr *expr)
213 {
214 struct nft_dynset *priv = nft_expr_priv(expr);
215
216 nf_tables_unbind_set(ctx, priv->set, &priv->binding);
217 if (priv->expr != NULL)
218 nft_expr_destroy(ctx, priv->expr);
219 }
220
221 static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr)
222 {
223 const struct nft_dynset *priv = nft_expr_priv(expr);
224
225 if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key))
226 goto nla_put_failure;
227 if (priv->set->flags & NFT_SET_MAP &&
228 nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data))
229 goto nla_put_failure;
230 if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op)))
231 goto nla_put_failure;
232 if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
233 goto nla_put_failure;
234 if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT,
235 cpu_to_be64(jiffies_to_msecs(priv->timeout)),
236 NFTA_DYNSET_PAD))
237 goto nla_put_failure;
238 if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr))
239 goto nla_put_failure;
240 return 0;
241
242 nla_put_failure:
243 return -1;
244 }
245
246 static struct nft_expr_type nft_dynset_type;
247 static const struct nft_expr_ops nft_dynset_ops = {
248 .type = &nft_dynset_type,
249 .size = NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
250 .eval = nft_dynset_eval,
251 .init = nft_dynset_init,
252 .destroy = nft_dynset_destroy,
253 .dump = nft_dynset_dump,
254 };
255
256 static struct nft_expr_type nft_dynset_type __read_mostly = {
257 .name = "dynset",
258 .ops = &nft_dynset_ops,
259 .policy = nft_dynset_policy,
260 .maxattr = NFTA_DYNSET_MAX,
261 .owner = THIS_MODULE,
262 };
263
264 int __init nft_dynset_module_init(void)
265 {
266 return nft_register_expr(&nft_dynset_type);
267 }
268
269 void nft_dynset_module_exit(void)
270 {
271 nft_unregister_expr(&nft_dynset_type);
272 }
273
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