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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2016 Laura Garcia <nevola@gmail.com>
4 */
5
6#include <linux/kernel.h>
7#include <linux/init.h>
8#include <linux/module.h>
9#include <linux/netlink.h>
10#include <linux/netfilter.h>
11#include <linux/netfilter/nf_tables.h>
12#include <net/netfilter/nf_tables.h>
13#include <net/netfilter/nf_tables_core.h>
14#include <linux/jhash.h>
15
16struct nft_jhash {
17 u8 sreg;
18 u8 dreg;
19 u8 len;
20 bool autogen_seed:1;
21 u32 modulus;
22 u32 seed;
23 u32 offset;
24};
25
26static void nft_jhash_eval(const struct nft_expr *expr,
27 struct nft_regs *regs,
28 const struct nft_pktinfo *pkt)
29{
30 struct nft_jhash *priv = nft_expr_priv(expr);
31 const void *data = ®s->data[priv->sreg];
32 u32 h;
33
34 h = reciprocal_scale(jhash(data, priv->len, priv->seed),
35 priv->modulus);
36
37 regs->data[priv->dreg] = h + priv->offset;
38}
39
40struct nft_symhash {
41 u8 dreg;
42 u32 modulus;
43 u32 offset;
44};
45
46static void nft_symhash_eval(const struct nft_expr *expr,
47 struct nft_regs *regs,
48 const struct nft_pktinfo *pkt)
49{
50 struct nft_symhash *priv = nft_expr_priv(expr);
51 struct sk_buff *skb = pkt->skb;
52 u32 h;
53
54 h = reciprocal_scale(__skb_get_hash_symmetric(skb), priv->modulus);
55
56 regs->data[priv->dreg] = h + priv->offset;
57}
58
59static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
60 [NFTA_HASH_SREG] = { .type = NLA_U32 },
61 [NFTA_HASH_DREG] = { .type = NLA_U32 },
62 [NFTA_HASH_LEN] = { .type = NLA_U32 },
63 [NFTA_HASH_MODULUS] = { .type = NLA_U32 },
64 [NFTA_HASH_SEED] = { .type = NLA_U32 },
65 [NFTA_HASH_OFFSET] = { .type = NLA_U32 },
66 [NFTA_HASH_TYPE] = { .type = NLA_U32 },
67};
68
69static int nft_jhash_init(const struct nft_ctx *ctx,
70 const struct nft_expr *expr,
71 const struct nlattr * const tb[])
72{
73 struct nft_jhash *priv = nft_expr_priv(expr);
74 u32 len;
75 int err;
76
77 if (!tb[NFTA_HASH_SREG] ||
78 !tb[NFTA_HASH_DREG] ||
79 !tb[NFTA_HASH_LEN] ||
80 !tb[NFTA_HASH_MODULUS])
81 return -EINVAL;
82
83 if (tb[NFTA_HASH_OFFSET])
84 priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
85
86 err = nft_parse_u32_check(tb[NFTA_HASH_LEN], U8_MAX, &len);
87 if (err < 0)
88 return err;
89 if (len == 0)
90 return -ERANGE;
91
92 priv->len = len;
93
94 err = nft_parse_register_load(tb[NFTA_HASH_SREG], &priv->sreg, len);
95 if (err < 0)
96 return err;
97
98 priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
99 if (priv->modulus < 1)
100 return -ERANGE;
101
102 if (priv->offset + priv->modulus - 1 < priv->offset)
103 return -EOVERFLOW;
104
105 if (tb[NFTA_HASH_SEED]) {
106 priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED]));
107 } else {
108 priv->autogen_seed = true;
109 get_random_bytes(&priv->seed, sizeof(priv->seed));
110 }
111
112 return nft_parse_register_store(ctx, tb[NFTA_HASH_DREG], &priv->dreg,
113 NULL, NFT_DATA_VALUE, sizeof(u32));
114}
115
116static int nft_symhash_init(const struct nft_ctx *ctx,
117 const struct nft_expr *expr,
118 const struct nlattr * const tb[])
119{
120 struct nft_symhash *priv = nft_expr_priv(expr);
121
122 if (!tb[NFTA_HASH_DREG] ||
123 !tb[NFTA_HASH_MODULUS])
124 return -EINVAL;
125
126 if (tb[NFTA_HASH_OFFSET])
127 priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
128
129 priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
130 if (priv->modulus < 1)
131 return -ERANGE;
132
133 if (priv->offset + priv->modulus - 1 < priv->offset)
134 return -EOVERFLOW;
135
136 return nft_parse_register_store(ctx, tb[NFTA_HASH_DREG],
137 &priv->dreg, NULL, NFT_DATA_VALUE,
138 sizeof(u32));
139}
140
141static int nft_jhash_dump(struct sk_buff *skb,
142 const struct nft_expr *expr)
143{
144 const struct nft_jhash *priv = nft_expr_priv(expr);
145
146 if (nft_dump_register(skb, NFTA_HASH_SREG, priv->sreg))
147 goto nla_put_failure;
148 if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
149 goto nla_put_failure;
150 if (nla_put_be32(skb, NFTA_HASH_LEN, htonl(priv->len)))
151 goto nla_put_failure;
152 if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
153 goto nla_put_failure;
154 if (!priv->autogen_seed &&
155 nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed)))
156 goto nla_put_failure;
157 if (priv->offset != 0)
158 if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
159 goto nla_put_failure;
160 if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_JENKINS)))
161 goto nla_put_failure;
162 return 0;
163
164nla_put_failure:
165 return -1;
166}
167
168static int nft_symhash_dump(struct sk_buff *skb,
169 const struct nft_expr *expr)
170{
171 const struct nft_symhash *priv = nft_expr_priv(expr);
172
173 if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
174 goto nla_put_failure;
175 if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
176 goto nla_put_failure;
177 if (priv->offset != 0)
178 if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
179 goto nla_put_failure;
180 if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_SYM)))
181 goto nla_put_failure;
182 return 0;
183
184nla_put_failure:
185 return -1;
186}
187
188static struct nft_expr_type nft_hash_type;
189static const struct nft_expr_ops nft_jhash_ops = {
190 .type = &nft_hash_type,
191 .size = NFT_EXPR_SIZE(sizeof(struct nft_jhash)),
192 .eval = nft_jhash_eval,
193 .init = nft_jhash_init,
194 .dump = nft_jhash_dump,
195};
196
197static const struct nft_expr_ops nft_symhash_ops = {
198 .type = &nft_hash_type,
199 .size = NFT_EXPR_SIZE(sizeof(struct nft_symhash)),
200 .eval = nft_symhash_eval,
201 .init = nft_symhash_init,
202 .dump = nft_symhash_dump,
203};
204
205static const struct nft_expr_ops *
206nft_hash_select_ops(const struct nft_ctx *ctx,
207 const struct nlattr * const tb[])
208{
209 u32 type;
210
211 if (!tb[NFTA_HASH_TYPE])
212 return &nft_jhash_ops;
213
214 type = ntohl(nla_get_be32(tb[NFTA_HASH_TYPE]));
215 switch (type) {
216 case NFT_HASH_SYM:
217 return &nft_symhash_ops;
218 case NFT_HASH_JENKINS:
219 return &nft_jhash_ops;
220 default:
221 break;
222 }
223 return ERR_PTR(-EOPNOTSUPP);
224}
225
226static struct nft_expr_type nft_hash_type __read_mostly = {
227 .name = "hash",
228 .select_ops = nft_hash_select_ops,
229 .policy = nft_hash_policy,
230 .maxattr = NFTA_HASH_MAX,
231 .owner = THIS_MODULE,
232};
233
234static int __init nft_hash_module_init(void)
235{
236 return nft_register_expr(&nft_hash_type);
237}
238
239static void __exit nft_hash_module_exit(void)
240{
241 nft_unregister_expr(&nft_hash_type);
242}
243
244module_init(nft_hash_module_init);
245module_exit(nft_hash_module_exit);
246
247MODULE_LICENSE("GPL");
248MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>");
249MODULE_ALIAS_NFT_EXPR("hash");
250MODULE_DESCRIPTION("Netfilter nftables hash module");
1/*
2 * Copyright (c) 2008-2014 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/module.h>
14#include <linux/list.h>
15#include <linux/jhash.h>
16#include <linux/netlink.h>
17#include <linux/vmalloc.h>
18#include <linux/netfilter.h>
19#include <linux/netfilter/nf_tables.h>
20#include <net/netfilter/nf_tables.h>
21
22#define NFT_HASH_MIN_SIZE 4
23
24struct nft_hash {
25 struct nft_hash_table __rcu *tbl;
26};
27
28struct nft_hash_table {
29 unsigned int size;
30 unsigned int elements;
31 struct nft_hash_elem __rcu *buckets[];
32};
33
34struct nft_hash_elem {
35 struct nft_hash_elem __rcu *next;
36 struct nft_data key;
37 struct nft_data data[];
38};
39
40#define nft_hash_for_each_entry(i, head) \
41 for (i = nft_dereference(head); i != NULL; i = nft_dereference(i->next))
42#define nft_hash_for_each_entry_rcu(i, head) \
43 for (i = rcu_dereference(head); i != NULL; i = rcu_dereference(i->next))
44
45static u32 nft_hash_rnd __read_mostly;
46static bool nft_hash_rnd_initted __read_mostly;
47
48static unsigned int nft_hash_data(const struct nft_data *data,
49 unsigned int hsize, unsigned int len)
50{
51 unsigned int h;
52
53 h = jhash(data->data, len, nft_hash_rnd);
54 return h & (hsize - 1);
55}
56
57static bool nft_hash_lookup(const struct nft_set *set,
58 const struct nft_data *key,
59 struct nft_data *data)
60{
61 const struct nft_hash *priv = nft_set_priv(set);
62 const struct nft_hash_table *tbl = rcu_dereference(priv->tbl);
63 const struct nft_hash_elem *he;
64 unsigned int h;
65
66 h = nft_hash_data(key, tbl->size, set->klen);
67 nft_hash_for_each_entry_rcu(he, tbl->buckets[h]) {
68 if (nft_data_cmp(&he->key, key, set->klen))
69 continue;
70 if (set->flags & NFT_SET_MAP)
71 nft_data_copy(data, he->data);
72 return true;
73 }
74 return false;
75}
76
77static void nft_hash_tbl_free(const struct nft_hash_table *tbl)
78{
79 if (is_vmalloc_addr(tbl))
80 vfree(tbl);
81 else
82 kfree(tbl);
83}
84
85static struct nft_hash_table *nft_hash_tbl_alloc(unsigned int nbuckets)
86{
87 struct nft_hash_table *tbl;
88 size_t size;
89
90 size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
91 tbl = kzalloc(size, GFP_KERNEL | __GFP_REPEAT | __GFP_NOWARN);
92 if (tbl == NULL)
93 tbl = vzalloc(size);
94 if (tbl == NULL)
95 return NULL;
96 tbl->size = nbuckets;
97
98 return tbl;
99}
100
101static void nft_hash_chain_unzip(const struct nft_set *set,
102 const struct nft_hash_table *ntbl,
103 struct nft_hash_table *tbl, unsigned int n)
104{
105 struct nft_hash_elem *he, *last, *next;
106 unsigned int h;
107
108 he = nft_dereference(tbl->buckets[n]);
109 if (he == NULL)
110 return;
111 h = nft_hash_data(&he->key, ntbl->size, set->klen);
112
113 /* Find last element of first chain hashing to bucket h */
114 last = he;
115 nft_hash_for_each_entry(he, he->next) {
116 if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
117 break;
118 last = he;
119 }
120
121 /* Unlink first chain from the old table */
122 RCU_INIT_POINTER(tbl->buckets[n], last->next);
123
124 /* If end of chain reached, done */
125 if (he == NULL)
126 return;
127
128 /* Find first element of second chain hashing to bucket h */
129 next = NULL;
130 nft_hash_for_each_entry(he, he->next) {
131 if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
132 continue;
133 next = he;
134 break;
135 }
136
137 /* Link the two chains */
138 RCU_INIT_POINTER(last->next, next);
139}
140
141static int nft_hash_tbl_expand(const struct nft_set *set, struct nft_hash *priv)
142{
143 struct nft_hash_table *tbl = nft_dereference(priv->tbl), *ntbl;
144 struct nft_hash_elem *he;
145 unsigned int i, h;
146 bool complete;
147
148 ntbl = nft_hash_tbl_alloc(tbl->size * 2);
149 if (ntbl == NULL)
150 return -ENOMEM;
151
152 /* Link new table's buckets to first element in the old table
153 * hashing to the new bucket.
154 */
155 for (i = 0; i < ntbl->size; i++) {
156 h = i < tbl->size ? i : i - tbl->size;
157 nft_hash_for_each_entry(he, tbl->buckets[h]) {
158 if (nft_hash_data(&he->key, ntbl->size, set->klen) != i)
159 continue;
160 RCU_INIT_POINTER(ntbl->buckets[i], he);
161 break;
162 }
163 }
164 ntbl->elements = tbl->elements;
165
166 /* Publish new table */
167 rcu_assign_pointer(priv->tbl, ntbl);
168
169 /* Unzip interleaved hash chains */
170 do {
171 /* Wait for readers to use new table/unzipped chains */
172 synchronize_rcu();
173
174 complete = true;
175 for (i = 0; i < tbl->size; i++) {
176 nft_hash_chain_unzip(set, ntbl, tbl, i);
177 if (tbl->buckets[i] != NULL)
178 complete = false;
179 }
180 } while (!complete);
181
182 nft_hash_tbl_free(tbl);
183 return 0;
184}
185
186static int nft_hash_tbl_shrink(const struct nft_set *set, struct nft_hash *priv)
187{
188 struct nft_hash_table *tbl = nft_dereference(priv->tbl), *ntbl;
189 struct nft_hash_elem __rcu **pprev;
190 unsigned int i;
191
192 ntbl = nft_hash_tbl_alloc(tbl->size / 2);
193 if (ntbl == NULL)
194 return -ENOMEM;
195
196 for (i = 0; i < ntbl->size; i++) {
197 ntbl->buckets[i] = tbl->buckets[i];
198
199 for (pprev = &ntbl->buckets[i]; *pprev != NULL;
200 pprev = &nft_dereference(*pprev)->next)
201 ;
202 RCU_INIT_POINTER(*pprev, tbl->buckets[i + ntbl->size]);
203 }
204 ntbl->elements = tbl->elements;
205
206 /* Publish new table */
207 rcu_assign_pointer(priv->tbl, ntbl);
208 synchronize_rcu();
209
210 nft_hash_tbl_free(tbl);
211 return 0;
212}
213
214static int nft_hash_insert(const struct nft_set *set,
215 const struct nft_set_elem *elem)
216{
217 struct nft_hash *priv = nft_set_priv(set);
218 struct nft_hash_table *tbl = nft_dereference(priv->tbl);
219 struct nft_hash_elem *he;
220 unsigned int size, h;
221
222 if (elem->flags != 0)
223 return -EINVAL;
224
225 size = sizeof(*he);
226 if (set->flags & NFT_SET_MAP)
227 size += sizeof(he->data[0]);
228
229 he = kzalloc(size, GFP_KERNEL);
230 if (he == NULL)
231 return -ENOMEM;
232
233 nft_data_copy(&he->key, &elem->key);
234 if (set->flags & NFT_SET_MAP)
235 nft_data_copy(he->data, &elem->data);
236
237 h = nft_hash_data(&he->key, tbl->size, set->klen);
238 RCU_INIT_POINTER(he->next, tbl->buckets[h]);
239 rcu_assign_pointer(tbl->buckets[h], he);
240 tbl->elements++;
241
242 /* Expand table when exceeding 75% load */
243 if (tbl->elements > tbl->size / 4 * 3)
244 nft_hash_tbl_expand(set, priv);
245
246 return 0;
247}
248
249static void nft_hash_elem_destroy(const struct nft_set *set,
250 struct nft_hash_elem *he)
251{
252 nft_data_uninit(&he->key, NFT_DATA_VALUE);
253 if (set->flags & NFT_SET_MAP)
254 nft_data_uninit(he->data, set->dtype);
255 kfree(he);
256}
257
258static void nft_hash_remove(const struct nft_set *set,
259 const struct nft_set_elem *elem)
260{
261 struct nft_hash *priv = nft_set_priv(set);
262 struct nft_hash_table *tbl = nft_dereference(priv->tbl);
263 struct nft_hash_elem *he, __rcu **pprev;
264
265 pprev = elem->cookie;
266 he = nft_dereference((*pprev));
267
268 RCU_INIT_POINTER(*pprev, he->next);
269 synchronize_rcu();
270 kfree(he);
271 tbl->elements--;
272
273 /* Shrink table beneath 30% load */
274 if (tbl->elements < tbl->size * 3 / 10 &&
275 tbl->size > NFT_HASH_MIN_SIZE)
276 nft_hash_tbl_shrink(set, priv);
277}
278
279static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem)
280{
281 const struct nft_hash *priv = nft_set_priv(set);
282 const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
283 struct nft_hash_elem __rcu * const *pprev;
284 struct nft_hash_elem *he;
285 unsigned int h;
286
287 h = nft_hash_data(&elem->key, tbl->size, set->klen);
288 pprev = &tbl->buckets[h];
289 nft_hash_for_each_entry(he, tbl->buckets[h]) {
290 if (nft_data_cmp(&he->key, &elem->key, set->klen)) {
291 pprev = &he->next;
292 continue;
293 }
294
295 elem->cookie = (void *)pprev;
296 elem->flags = 0;
297 if (set->flags & NFT_SET_MAP)
298 nft_data_copy(&elem->data, he->data);
299 return 0;
300 }
301 return -ENOENT;
302}
303
304static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set,
305 struct nft_set_iter *iter)
306{
307 const struct nft_hash *priv = nft_set_priv(set);
308 const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
309 const struct nft_hash_elem *he;
310 struct nft_set_elem elem;
311 unsigned int i;
312
313 for (i = 0; i < tbl->size; i++) {
314 nft_hash_for_each_entry(he, tbl->buckets[i]) {
315 if (iter->count < iter->skip)
316 goto cont;
317
318 memcpy(&elem.key, &he->key, sizeof(elem.key));
319 if (set->flags & NFT_SET_MAP)
320 memcpy(&elem.data, he->data, sizeof(elem.data));
321 elem.flags = 0;
322
323 iter->err = iter->fn(ctx, set, iter, &elem);
324 if (iter->err < 0)
325 return;
326cont:
327 iter->count++;
328 }
329 }
330}
331
332static unsigned int nft_hash_privsize(const struct nlattr * const nla[])
333{
334 return sizeof(struct nft_hash);
335}
336
337static int nft_hash_init(const struct nft_set *set,
338 const struct nlattr * const tb[])
339{
340 struct nft_hash *priv = nft_set_priv(set);
341 struct nft_hash_table *tbl;
342
343 if (unlikely(!nft_hash_rnd_initted)) {
344 get_random_bytes(&nft_hash_rnd, 4);
345 nft_hash_rnd_initted = true;
346 }
347
348 tbl = nft_hash_tbl_alloc(NFT_HASH_MIN_SIZE);
349 if (tbl == NULL)
350 return -ENOMEM;
351 RCU_INIT_POINTER(priv->tbl, tbl);
352 return 0;
353}
354
355static void nft_hash_destroy(const struct nft_set *set)
356{
357 const struct nft_hash *priv = nft_set_priv(set);
358 const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
359 struct nft_hash_elem *he, *next;
360 unsigned int i;
361
362 for (i = 0; i < tbl->size; i++) {
363 for (he = nft_dereference(tbl->buckets[i]); he != NULL;
364 he = next) {
365 next = nft_dereference(he->next);
366 nft_hash_elem_destroy(set, he);
367 }
368 }
369 kfree(tbl);
370}
371
372static struct nft_set_ops nft_hash_ops __read_mostly = {
373 .privsize = nft_hash_privsize,
374 .init = nft_hash_init,
375 .destroy = nft_hash_destroy,
376 .get = nft_hash_get,
377 .insert = nft_hash_insert,
378 .remove = nft_hash_remove,
379 .lookup = nft_hash_lookup,
380 .walk = nft_hash_walk,
381 .features = NFT_SET_MAP,
382 .owner = THIS_MODULE,
383};
384
385static int __init nft_hash_module_init(void)
386{
387 return nft_register_set(&nft_hash_ops);
388}
389
390static void __exit nft_hash_module_exit(void)
391{
392 nft_unregister_set(&nft_hash_ops);
393}
394
395module_init(nft_hash_module_init);
396module_exit(nft_hash_module_exit);
397
398MODULE_LICENSE("GPL");
399MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
400MODULE_ALIAS_NFT_SET();