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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 | bool invert; | |
26 | u64 timeout; | |
27 | struct nft_expr *expr; | |
28 | struct nft_set_binding binding; | |
29 | }; | |
30 | ||
31 | static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr, | |
32 | struct nft_regs *regs) | |
33 | { | |
34 | const struct nft_dynset *priv = nft_expr_priv(expr); | |
35 | struct nft_set_ext *ext; | |
36 | u64 timeout; | |
37 | void *elem; | |
38 | ||
39 | if (set->size && !atomic_add_unless(&set->nelems, 1, set->size)) | |
40 | return NULL; | |
41 | ||
42 | timeout = priv->timeout ? : set->timeout; | |
43 | elem = nft_set_elem_init(set, &priv->tmpl, | |
44 | ®s->data[priv->sreg_key], | |
45 | ®s->data[priv->sreg_data], | |
46 | timeout, GFP_ATOMIC); | |
47 | if (elem == NULL) | |
48 | goto err1; | |
49 | ||
50 | ext = nft_set_elem_ext(set, elem); | |
51 | if (priv->expr != NULL && | |
52 | nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0) | |
53 | goto err2; | |
54 | ||
55 | return elem; | |
56 | ||
57 | err2: | |
58 | nft_set_elem_destroy(set, elem, false); | |
59 | err1: | |
60 | if (set->size) | |
61 | atomic_dec(&set->nelems); | |
62 | return NULL; | |
63 | } | |
64 | ||
65 | static void nft_dynset_eval(const struct nft_expr *expr, | |
66 | struct nft_regs *regs, | |
67 | const struct nft_pktinfo *pkt) | |
68 | { | |
69 | const struct nft_dynset *priv = nft_expr_priv(expr); | |
70 | struct nft_set *set = priv->set; | |
71 | const struct nft_set_ext *ext; | |
72 | const struct nft_expr *sexpr; | |
73 | u64 timeout; | |
74 | ||
75 | if (set->ops->update(set, ®s->data[priv->sreg_key], nft_dynset_new, | |
76 | expr, regs, &ext)) { | |
77 | sexpr = NULL; | |
78 | if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR)) | |
79 | sexpr = nft_set_ext_expr(ext); | |
80 | ||
81 | if (priv->op == NFT_DYNSET_OP_UPDATE && | |
82 | nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) { | |
83 | timeout = priv->timeout ? : set->timeout; | |
84 | *nft_set_ext_expiration(ext) = jiffies + timeout; | |
85 | } | |
86 | ||
87 | if (sexpr != NULL) | |
88 | sexpr->ops->eval(sexpr, regs, pkt); | |
89 | ||
90 | if (priv->invert) | |
91 | regs->verdict.code = NFT_BREAK; | |
92 | return; | |
93 | } | |
94 | ||
95 | if (!priv->invert) | |
96 | regs->verdict.code = NFT_BREAK; | |
97 | } | |
98 | ||
99 | static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = { | |
100 | [NFTA_DYNSET_SET_NAME] = { .type = NLA_STRING, | |
101 | .len = NFT_SET_MAXNAMELEN - 1 }, | |
102 | [NFTA_DYNSET_SET_ID] = { .type = NLA_U32 }, | |
103 | [NFTA_DYNSET_OP] = { .type = NLA_U32 }, | |
104 | [NFTA_DYNSET_SREG_KEY] = { .type = NLA_U32 }, | |
105 | [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 }, | |
106 | [NFTA_DYNSET_TIMEOUT] = { .type = NLA_U64 }, | |
107 | [NFTA_DYNSET_EXPR] = { .type = NLA_NESTED }, | |
108 | [NFTA_DYNSET_FLAGS] = { .type = NLA_U32 }, | |
109 | }; | |
110 | ||
111 | static int nft_dynset_init(const struct nft_ctx *ctx, | |
112 | const struct nft_expr *expr, | |
113 | const struct nlattr * const tb[]) | |
114 | { | |
115 | struct nft_dynset *priv = nft_expr_priv(expr); | |
116 | u8 genmask = nft_genmask_next(ctx->net); | |
117 | struct nft_set *set; | |
118 | u64 timeout; | |
119 | int err; | |
120 | ||
121 | if (tb[NFTA_DYNSET_SET_NAME] == NULL || | |
122 | tb[NFTA_DYNSET_OP] == NULL || | |
123 | tb[NFTA_DYNSET_SREG_KEY] == NULL) | |
124 | return -EINVAL; | |
125 | ||
126 | if (tb[NFTA_DYNSET_FLAGS]) { | |
127 | u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS])); | |
128 | ||
129 | if (flags & ~NFT_DYNSET_F_INV) | |
130 | return -EINVAL; | |
131 | if (flags & NFT_DYNSET_F_INV) | |
132 | priv->invert = true; | |
133 | } | |
134 | ||
135 | set = nft_set_lookup(ctx->net, ctx->table, tb[NFTA_DYNSET_SET_NAME], | |
136 | tb[NFTA_DYNSET_SET_ID], genmask); | |
137 | if (IS_ERR(set)) | |
138 | return PTR_ERR(set); | |
139 | ||
140 | if (set->ops->update == NULL) | |
141 | return -EOPNOTSUPP; | |
142 | ||
143 | if (set->flags & NFT_SET_CONSTANT) | |
144 | return -EBUSY; | |
145 | ||
146 | priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP])); | |
147 | switch (priv->op) { | |
148 | case NFT_DYNSET_OP_ADD: | |
149 | break; | |
150 | case NFT_DYNSET_OP_UPDATE: | |
151 | if (!(set->flags & NFT_SET_TIMEOUT)) | |
152 | return -EOPNOTSUPP; | |
153 | break; | |
154 | default: | |
155 | return -EOPNOTSUPP; | |
156 | } | |
157 | ||
158 | timeout = 0; | |
159 | if (tb[NFTA_DYNSET_TIMEOUT] != NULL) { | |
160 | if (!(set->flags & NFT_SET_TIMEOUT)) | |
161 | return -EINVAL; | |
162 | timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64( | |
163 | tb[NFTA_DYNSET_TIMEOUT]))); | |
164 | } | |
165 | ||
166 | priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]); | |
167 | err = nft_validate_register_load(priv->sreg_key, set->klen);; | |
168 | if (err < 0) | |
169 | return err; | |
170 | ||
171 | if (tb[NFTA_DYNSET_SREG_DATA] != NULL) { | |
172 | if (!(set->flags & NFT_SET_MAP)) | |
173 | return -EINVAL; | |
174 | if (set->dtype == NFT_DATA_VERDICT) | |
175 | return -EOPNOTSUPP; | |
176 | ||
177 | priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]); | |
178 | err = nft_validate_register_load(priv->sreg_data, set->dlen); | |
179 | if (err < 0) | |
180 | return err; | |
181 | } else if (set->flags & NFT_SET_MAP) | |
182 | return -EINVAL; | |
183 | ||
184 | if (tb[NFTA_DYNSET_EXPR] != NULL) { | |
185 | if (!(set->flags & NFT_SET_EVAL)) | |
186 | return -EINVAL; | |
187 | if (!(set->flags & NFT_SET_ANONYMOUS)) | |
188 | return -EOPNOTSUPP; | |
189 | ||
190 | priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]); | |
191 | if (IS_ERR(priv->expr)) | |
192 | return PTR_ERR(priv->expr); | |
193 | ||
194 | err = -EOPNOTSUPP; | |
195 | if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL)) | |
196 | goto err1; | |
197 | } else if (set->flags & NFT_SET_EVAL) | |
198 | return -EINVAL; | |
199 | ||
200 | nft_set_ext_prepare(&priv->tmpl); | |
201 | nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen); | |
202 | if (set->flags & NFT_SET_MAP) | |
203 | nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen); | |
204 | if (priv->expr != NULL) | |
205 | nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR, | |
206 | priv->expr->ops->size); | |
207 | if (set->flags & NFT_SET_TIMEOUT) { | |
208 | if (timeout || set->timeout) | |
209 | nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION); | |
210 | } | |
211 | ||
212 | priv->timeout = timeout; | |
213 | ||
214 | err = nf_tables_bind_set(ctx, set, &priv->binding); | |
215 | if (err < 0) | |
216 | goto err1; | |
217 | ||
218 | priv->set = set; | |
219 | return 0; | |
220 | ||
221 | err1: | |
222 | if (priv->expr != NULL) | |
223 | nft_expr_destroy(ctx, priv->expr); | |
224 | return err; | |
225 | } | |
226 | ||
227 | static void nft_dynset_destroy(const struct nft_ctx *ctx, | |
228 | const struct nft_expr *expr) | |
229 | { | |
230 | struct nft_dynset *priv = nft_expr_priv(expr); | |
231 | ||
232 | nf_tables_unbind_set(ctx, priv->set, &priv->binding); | |
233 | if (priv->expr != NULL) | |
234 | nft_expr_destroy(ctx, priv->expr); | |
235 | } | |
236 | ||
237 | static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr) | |
238 | { | |
239 | const struct nft_dynset *priv = nft_expr_priv(expr); | |
240 | u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0; | |
241 | ||
242 | if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key)) | |
243 | goto nla_put_failure; | |
244 | if (priv->set->flags & NFT_SET_MAP && | |
245 | nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data)) | |
246 | goto nla_put_failure; | |
247 | if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op))) | |
248 | goto nla_put_failure; | |
249 | if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name)) | |
250 | goto nla_put_failure; | |
251 | if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT, | |
252 | cpu_to_be64(jiffies_to_msecs(priv->timeout)), | |
253 | NFTA_DYNSET_PAD)) | |
254 | goto nla_put_failure; | |
255 | if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr)) | |
256 | goto nla_put_failure; | |
257 | if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags))) | |
258 | goto nla_put_failure; | |
259 | return 0; | |
260 | ||
261 | nla_put_failure: | |
262 | return -1; | |
263 | } | |
264 | ||
265 | static const struct nft_expr_ops nft_dynset_ops = { | |
266 | .type = &nft_dynset_type, | |
267 | .size = NFT_EXPR_SIZE(sizeof(struct nft_dynset)), | |
268 | .eval = nft_dynset_eval, | |
269 | .init = nft_dynset_init, | |
270 | .destroy = nft_dynset_destroy, | |
271 | .dump = nft_dynset_dump, | |
272 | }; | |
273 | ||
274 | struct nft_expr_type nft_dynset_type __read_mostly = { | |
275 | .name = "dynset", | |
276 | .ops = &nft_dynset_ops, | |
277 | .policy = nft_dynset_policy, | |
278 | .maxattr = NFTA_DYNSET_MAX, | |
279 | .owner = THIS_MODULE, | |
280 | }; |