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/log2.h>
16 #include <linux/jhash.h>
17 #include <linux/netlink.h>
18 #include <linux/workqueue.h>
19 #include <linux/rhashtable.h>
20 #include <linux/netfilter.h>
21 #include <linux/netfilter/nf_tables.h>
22 #include <net/netfilter/nf_tables.h>
23
24 /* We target a hash table size of 4, element hint is 75% of final size */
25 #define NFT_RHASH_ELEMENT_HINT 3
26
27 struct nft_rhash {
28 struct rhashtable ht;
29 struct delayed_work gc_work;
30 };
31
32 struct nft_rhash_elem {
33 struct rhash_head node;
34 struct nft_set_ext ext;
35 };
36
37 struct nft_rhash_cmp_arg {
38 const struct nft_set *set;
39 const u32 *key;
40 u8 genmask;
41 };
42
43 static inline u32 nft_rhash_key(const void *data, u32 len, u32 seed)
44 {
45 const struct nft_rhash_cmp_arg *arg = data;
46
47 return jhash(arg->key, len, seed);
48 }
49
50 static inline u32 nft_rhash_obj(const void *data, u32 len, u32 seed)
51 {
52 const struct nft_rhash_elem *he = data;
53
54 return jhash(nft_set_ext_key(&he->ext), len, seed);
55 }
56
57 static inline int nft_rhash_cmp(struct rhashtable_compare_arg *arg,
58 const void *ptr)
59 {
60 const struct nft_rhash_cmp_arg *x = arg->key;
61 const struct nft_rhash_elem *he = ptr;
62
63 if (memcmp(nft_set_ext_key(&he->ext), x->key, x->set->klen))
64 return 1;
65 if (nft_set_elem_expired(&he->ext))
66 return 1;
67 if (!nft_set_elem_active(&he->ext, x->genmask))
68 return 1;
69 return 0;
70 }
71
72 static const struct rhashtable_params nft_rhash_params = {
73 .head_offset = offsetof(struct nft_rhash_elem, node),
74 .hashfn = nft_rhash_key,
75 .obj_hashfn = nft_rhash_obj,
76 .obj_cmpfn = nft_rhash_cmp,
77 .automatic_shrinking = true,
78 };
79
80 static bool nft_rhash_lookup(const struct net *net, const struct nft_set *set,
81 const u32 *key, const struct nft_set_ext **ext)
82 {
83 struct nft_rhash *priv = nft_set_priv(set);
84 const struct nft_rhash_elem *he;
85 struct nft_rhash_cmp_arg arg = {
86 .genmask = nft_genmask_cur(net),
87 .set = set,
88 .key = key,
89 };
90
91 he = rhashtable_lookup_fast(&priv->ht, &arg, nft_rhash_params);
92 if (he != NULL)
93 *ext = &he->ext;
94
95 return !!he;
96 }
97
98 static bool nft_rhash_update(struct nft_set *set, const u32 *key,
99 void *(*new)(struct nft_set *,
100 const struct nft_expr *,
101 struct nft_regs *regs),
102 const struct nft_expr *expr,
103 struct nft_regs *regs,
104 const struct nft_set_ext **ext)
105 {
106 struct nft_rhash *priv = nft_set_priv(set);
107 struct nft_rhash_elem *he, *prev;
108 struct nft_rhash_cmp_arg arg = {
109 .genmask = NFT_GENMASK_ANY,
110 .set = set,
111 .key = key,
112 };
113
114 he = rhashtable_lookup_fast(&priv->ht, &arg, nft_rhash_params);
115 if (he != NULL)
116 goto out;
117
118 he = new(set, expr, regs);
119 if (he == NULL)
120 goto err1;
121
122 prev = rhashtable_lookup_get_insert_key(&priv->ht, &arg, &he->node,
123 nft_rhash_params);
124 if (IS_ERR(prev))
125 goto err2;
126
127 /* Another cpu may race to insert the element with the same key */
128 if (prev) {
129 nft_set_elem_destroy(set, he, true);
130 he = prev;
131 }
132
133 out:
134 *ext = &he->ext;
135 return true;
136
137 err2:
138 nft_set_elem_destroy(set, he, true);
139 err1:
140 return false;
141 }
142
143 static int nft_rhash_insert(const struct net *net, const struct nft_set *set,
144 const struct nft_set_elem *elem,
145 struct nft_set_ext **ext)
146 {
147 struct nft_rhash *priv = nft_set_priv(set);
148 struct nft_rhash_elem *he = elem->priv;
149 struct nft_rhash_cmp_arg arg = {
150 .genmask = nft_genmask_next(net),
151 .set = set,
152 .key = elem->key.val.data,
153 };
154 struct nft_rhash_elem *prev;
155
156 prev = rhashtable_lookup_get_insert_key(&priv->ht, &arg, &he->node,
157 nft_rhash_params);
158 if (IS_ERR(prev))
159 return PTR_ERR(prev);
160 if (prev) {
161 *ext = &prev->ext;
162 return -EEXIST;
163 }
164 return 0;
165 }
166
167 static void nft_rhash_activate(const struct net *net, const struct nft_set *set,
168 const struct nft_set_elem *elem)
169 {
170 struct nft_rhash_elem *he = elem->priv;
171
172 nft_set_elem_change_active(net, set, &he->ext);
173 nft_set_elem_clear_busy(&he->ext);
174 }
175
176 static bool nft_rhash_flush(const struct net *net,
177 const struct nft_set *set, void *priv)
178 {
179 struct nft_rhash_elem *he = priv;
180
181 if (!nft_set_elem_mark_busy(&he->ext) ||
182 !nft_is_active(net, &he->ext)) {
183 nft_set_elem_change_active(net, set, &he->ext);
184 return true;
185 }
186 return false;
187 }
188
189 static void *nft_rhash_deactivate(const struct net *net,
190 const struct nft_set *set,
191 const struct nft_set_elem *elem)
192 {
193 struct nft_rhash *priv = nft_set_priv(set);
194 struct nft_rhash_elem *he;
195 struct nft_rhash_cmp_arg arg = {
196 .genmask = nft_genmask_next(net),
197 .set = set,
198 .key = elem->key.val.data,
199 };
200
201 rcu_read_lock();
202 he = rhashtable_lookup_fast(&priv->ht, &arg, nft_rhash_params);
203 if (he != NULL &&
204 !nft_rhash_flush(net, set, he))
205 he = NULL;
206
207 rcu_read_unlock();
208
209 return he;
210 }
211
212 static void nft_rhash_remove(const struct net *net,
213 const struct nft_set *set,
214 const struct nft_set_elem *elem)
215 {
216 struct nft_rhash *priv = nft_set_priv(set);
217 struct nft_rhash_elem *he = elem->priv;
218
219 rhashtable_remove_fast(&priv->ht, &he->node, nft_rhash_params);
220 }
221
222 static void nft_rhash_walk(const struct nft_ctx *ctx, struct nft_set *set,
223 struct nft_set_iter *iter)
224 {
225 struct nft_rhash *priv = nft_set_priv(set);
226 struct nft_rhash_elem *he;
227 struct rhashtable_iter hti;
228 struct nft_set_elem elem;
229 int err;
230
231 err = rhashtable_walk_init(&priv->ht, &hti, GFP_ATOMIC);
232 iter->err = err;
233 if (err)
234 return;
235
236 err = rhashtable_walk_start(&hti);
237 if (err && err != -EAGAIN) {
238 iter->err = err;
239 goto out;
240 }
241
242 while ((he = rhashtable_walk_next(&hti))) {
243 if (IS_ERR(he)) {
244 err = PTR_ERR(he);
245 if (err != -EAGAIN) {
246 iter->err = err;
247 goto out;
248 }
249
250 continue;
251 }
252
253 if (iter->count < iter->skip)
254 goto cont;
255 if (nft_set_elem_expired(&he->ext))
256 goto cont;
257 if (!nft_set_elem_active(&he->ext, iter->genmask))
258 goto cont;
259
260 elem.priv = he;
261
262 iter->err = iter->fn(ctx, set, iter, &elem);
263 if (iter->err < 0)
264 goto out;
265
266 cont:
267 iter->count++;
268 }
269
270 out:
271 rhashtable_walk_stop(&hti);
272 rhashtable_walk_exit(&hti);
273 }
274
275 static void nft_rhash_gc(struct work_struct *work)
276 {
277 struct nft_set *set;
278 struct nft_rhash_elem *he;
279 struct nft_rhash *priv;
280 struct nft_set_gc_batch *gcb = NULL;
281 struct rhashtable_iter hti;
282 int err;
283
284 priv = container_of(work, struct nft_rhash, gc_work.work);
285 set = nft_set_container_of(priv);
286
287 err = rhashtable_walk_init(&priv->ht, &hti, GFP_KERNEL);
288 if (err)
289 goto schedule;
290
291 err = rhashtable_walk_start(&hti);
292 if (err && err != -EAGAIN)
293 goto out;
294
295 while ((he = rhashtable_walk_next(&hti))) {
296 if (IS_ERR(he)) {
297 if (PTR_ERR(he) != -EAGAIN)
298 goto out;
299 continue;
300 }
301
302 if (!nft_set_elem_expired(&he->ext))
303 continue;
304 if (nft_set_elem_mark_busy(&he->ext))
305 continue;
306
307 gcb = nft_set_gc_batch_check(set, gcb, GFP_ATOMIC);
308 if (gcb == NULL)
309 goto out;
310 rhashtable_remove_fast(&priv->ht, &he->node, nft_rhash_params);
311 atomic_dec(&set->nelems);
312 nft_set_gc_batch_add(gcb, he);
313 }
314 out:
315 rhashtable_walk_stop(&hti);
316 rhashtable_walk_exit(&hti);
317
318 nft_set_gc_batch_complete(gcb);
319 schedule:
320 queue_delayed_work(system_power_efficient_wq, &priv->gc_work,
321 nft_set_gc_interval(set));
322 }
323
324 static unsigned int nft_rhash_privsize(const struct nlattr * const nla[],
325 const struct nft_set_desc *desc)
326 {
327 return sizeof(struct nft_rhash);
328 }
329
330 static int nft_rhash_init(const struct nft_set *set,
331 const struct nft_set_desc *desc,
332 const struct nlattr * const tb[])
333 {
334 struct nft_rhash *priv = nft_set_priv(set);
335 struct rhashtable_params params = nft_rhash_params;
336 int err;
337
338 params.nelem_hint = desc->size ?: NFT_RHASH_ELEMENT_HINT;
339 params.key_len = set->klen;
340
341 err = rhashtable_init(&priv->ht, ¶ms);
342 if (err < 0)
343 return err;
344
345 INIT_DEFERRABLE_WORK(&priv->gc_work, nft_rhash_gc);
346 if (set->flags & NFT_SET_TIMEOUT)
347 queue_delayed_work(system_power_efficient_wq, &priv->gc_work,
348 nft_set_gc_interval(set));
349 return 0;
350 }
351
352 static void nft_rhash_elem_destroy(void *ptr, void *arg)
353 {
354 nft_set_elem_destroy(arg, ptr, true);
355 }
356
357 static void nft_rhash_destroy(const struct nft_set *set)
358 {
359 struct nft_rhash *priv = nft_set_priv(set);
360
361 cancel_delayed_work_sync(&priv->gc_work);
362 rhashtable_free_and_destroy(&priv->ht, nft_rhash_elem_destroy,
363 (void *)set);
364 }
365
366 static u32 nft_hash_buckets(u32 size)
367 {
368 return roundup_pow_of_two(size * 4 / 3);
369 }
370
371 static bool nft_rhash_estimate(const struct nft_set_desc *desc, u32 features,
372 struct nft_set_estimate *est)
373 {
374 est->size = ~0;
375 est->lookup = NFT_SET_CLASS_O_1;
376 est->space = NFT_SET_CLASS_O_N;
377
378 return true;
379 }
380
381 struct nft_hash {
382 u32 seed;
383 u32 buckets;
384 struct hlist_head table[];
385 };
386
387 struct nft_hash_elem {
388 struct hlist_node node;
389 struct nft_set_ext ext;
390 };
391
392 static bool nft_hash_lookup(const struct net *net, const struct nft_set *set,
393 const u32 *key, const struct nft_set_ext **ext)
394 {
395 struct nft_hash *priv = nft_set_priv(set);
396 u8 genmask = nft_genmask_cur(net);
397 const struct nft_hash_elem *he;
398 u32 hash;
399
400 hash = jhash(key, set->klen, priv->seed);
401 hash = reciprocal_scale(hash, priv->buckets);
402 hlist_for_each_entry_rcu(he, &priv->table[hash], node) {
403 if (!memcmp(nft_set_ext_key(&he->ext), key, set->klen) &&
404 nft_set_elem_active(&he->ext, genmask)) {
405 *ext = &he->ext;
406 return true;
407 }
408 }
409 return false;
410 }
411
412 /* nft_hash_select_ops() makes sure key size can be either 2 or 4 bytes . */
413 static inline u32 nft_hash_key(const u32 *key, u32 klen)
414 {
415 if (klen == 4)
416 return *key;
417
418 return *(u16 *)key;
419 }
420
421 static bool nft_hash_lookup_fast(const struct net *net,
422 const struct nft_set *set,
423 const u32 *key, const struct nft_set_ext **ext)
424 {
425 struct nft_hash *priv = nft_set_priv(set);
426 u8 genmask = nft_genmask_cur(net);
427 const struct nft_hash_elem *he;
428 u32 hash, k1, k2;
429
430 k1 = nft_hash_key(key, set->klen);
431 hash = jhash_1word(k1, priv->seed);
432 hash = reciprocal_scale(hash, priv->buckets);
433 hlist_for_each_entry_rcu(he, &priv->table[hash], node) {
434 k2 = nft_hash_key(nft_set_ext_key(&he->ext)->data, set->klen);
435 if (k1 == k2 &&
436 nft_set_elem_active(&he->ext, genmask)) {
437 *ext = &he->ext;
438 return true;
439 }
440 }
441 return false;
442 }
443
444 static int nft_hash_insert(const struct net *net, const struct nft_set *set,
445 const struct nft_set_elem *elem,
446 struct nft_set_ext **ext)
447 {
448 struct nft_hash_elem *this = elem->priv, *he;
449 struct nft_hash *priv = nft_set_priv(set);
450 u8 genmask = nft_genmask_next(net);
451 u32 hash;
452
453 hash = jhash(nft_set_ext_key(&this->ext), set->klen, priv->seed);
454 hash = reciprocal_scale(hash, priv->buckets);
455 hlist_for_each_entry(he, &priv->table[hash], node) {
456 if (!memcmp(nft_set_ext_key(&this->ext),
457 nft_set_ext_key(&he->ext), set->klen) &&
458 nft_set_elem_active(&he->ext, genmask)) {
459 *ext = &he->ext;
460 return -EEXIST;
461 }
462 }
463 hlist_add_head_rcu(&this->node, &priv->table[hash]);
464 return 0;
465 }
466
467 static void nft_hash_activate(const struct net *net, const struct nft_set *set,
468 const struct nft_set_elem *elem)
469 {
470 struct nft_hash_elem *he = elem->priv;
471
472 nft_set_elem_change_active(net, set, &he->ext);
473 }
474
475 static bool nft_hash_flush(const struct net *net,
476 const struct nft_set *set, void *priv)
477 {
478 struct nft_hash_elem *he = priv;
479
480 nft_set_elem_change_active(net, set, &he->ext);
481 return true;
482 }
483
484 static void *nft_hash_deactivate(const struct net *net,
485 const struct nft_set *set,
486 const struct nft_set_elem *elem)
487 {
488 struct nft_hash *priv = nft_set_priv(set);
489 struct nft_hash_elem *this = elem->priv, *he;
490 u8 genmask = nft_genmask_next(net);
491 u32 hash;
492
493 hash = jhash(nft_set_ext_key(&this->ext), set->klen, priv->seed);
494 hash = reciprocal_scale(hash, priv->buckets);
495 hlist_for_each_entry(he, &priv->table[hash], node) {
496 if (!memcmp(nft_set_ext_key(&this->ext), &elem->key.val,
497 set->klen) ||
498 nft_set_elem_active(&he->ext, genmask)) {
499 nft_set_elem_change_active(net, set, &he->ext);
500 return he;
501 }
502 }
503 return NULL;
504 }
505
506 static void nft_hash_remove(const struct net *net,
507 const struct nft_set *set,
508 const struct nft_set_elem *elem)
509 {
510 struct nft_hash_elem *he = elem->priv;
511
512 hlist_del_rcu(&he->node);
513 }
514
515 static void nft_hash_walk(const struct nft_ctx *ctx, struct nft_set *set,
516 struct nft_set_iter *iter)
517 {
518 struct nft_hash *priv = nft_set_priv(set);
519 struct nft_hash_elem *he;
520 struct nft_set_elem elem;
521 int i;
522
523 for (i = 0; i < priv->buckets; i++) {
524 hlist_for_each_entry_rcu(he, &priv->table[i], node) {
525 if (iter->count < iter->skip)
526 goto cont;
527 if (!nft_set_elem_active(&he->ext, iter->genmask))
528 goto cont;
529
530 elem.priv = he;
531
532 iter->err = iter->fn(ctx, set, iter, &elem);
533 if (iter->err < 0)
534 return;
535 cont:
536 iter->count++;
537 }
538 }
539 }
540
541 static unsigned int nft_hash_privsize(const struct nlattr * const nla[],
542 const struct nft_set_desc *desc)
543 {
544 return sizeof(struct nft_hash) +
545 nft_hash_buckets(desc->size) * sizeof(struct hlist_head);
546 }
547
548 static int nft_hash_init(const struct nft_set *set,
549 const struct nft_set_desc *desc,
550 const struct nlattr * const tb[])
551 {
552 struct nft_hash *priv = nft_set_priv(set);
553
554 priv->buckets = nft_hash_buckets(desc->size);
555 get_random_bytes(&priv->seed, sizeof(priv->seed));
556
557 return 0;
558 }
559
560 static void nft_hash_destroy(const struct nft_set *set)
561 {
562 struct nft_hash *priv = nft_set_priv(set);
563 struct nft_hash_elem *he;
564 struct hlist_node *next;
565 int i;
566
567 for (i = 0; i < priv->buckets; i++) {
568 hlist_for_each_entry_safe(he, next, &priv->table[i], node) {
569 hlist_del_rcu(&he->node);
570 nft_set_elem_destroy(set, he, true);
571 }
572 }
573 }
574
575 static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features,
576 struct nft_set_estimate *est)
577 {
578 est->size = sizeof(struct nft_hash) +
579 nft_hash_buckets(desc->size) * sizeof(struct hlist_head) +
580 desc->size * sizeof(struct nft_hash_elem);
581 est->lookup = NFT_SET_CLASS_O_1;
582 est->space = NFT_SET_CLASS_O_N;
583
584 return true;
585 }
586
587 static struct nft_set_type nft_hash_type;
588 static struct nft_set_ops nft_rhash_ops __read_mostly = {
589 .type = &nft_hash_type,
590 .privsize = nft_rhash_privsize,
591 .elemsize = offsetof(struct nft_rhash_elem, ext),
592 .estimate = nft_rhash_estimate,
593 .init = nft_rhash_init,
594 .destroy = nft_rhash_destroy,
595 .insert = nft_rhash_insert,
596 .activate = nft_rhash_activate,
597 .deactivate = nft_rhash_deactivate,
598 .flush = nft_rhash_flush,
599 .remove = nft_rhash_remove,
600 .lookup = nft_rhash_lookup,
601 .update = nft_rhash_update,
602 .walk = nft_rhash_walk,
603 .features = NFT_SET_MAP | NFT_SET_OBJECT | NFT_SET_TIMEOUT,
604 };
605
606 static struct nft_set_ops nft_hash_ops __read_mostly = {
607 .type = &nft_hash_type,
608 .privsize = nft_hash_privsize,
609 .elemsize = offsetof(struct nft_hash_elem, ext),
610 .estimate = nft_hash_estimate,
611 .init = nft_hash_init,
612 .destroy = nft_hash_destroy,
613 .insert = nft_hash_insert,
614 .activate = nft_hash_activate,
615 .deactivate = nft_hash_deactivate,
616 .flush = nft_hash_flush,
617 .remove = nft_hash_remove,
618 .lookup = nft_hash_lookup,
619 .walk = nft_hash_walk,
620 .features = NFT_SET_MAP | NFT_SET_OBJECT,
621 };
622
623 static struct nft_set_ops nft_hash_fast_ops __read_mostly = {
624 .type = &nft_hash_type,
625 .privsize = nft_hash_privsize,
626 .elemsize = offsetof(struct nft_hash_elem, ext),
627 .estimate = nft_hash_estimate,
628 .init = nft_hash_init,
629 .destroy = nft_hash_destroy,
630 .insert = nft_hash_insert,
631 .activate = nft_hash_activate,
632 .deactivate = nft_hash_deactivate,
633 .flush = nft_hash_flush,
634 .remove = nft_hash_remove,
635 .lookup = nft_hash_lookup_fast,
636 .walk = nft_hash_walk,
637 .features = NFT_SET_MAP | NFT_SET_OBJECT,
638 };
639
640 static const struct nft_set_ops *
641 nft_hash_select_ops(const struct nft_ctx *ctx, const struct nft_set_desc *desc,
642 u32 flags)
643 {
644 if (desc->size) {
645 switch (desc->klen) {
646 case 4:
647 return &nft_hash_fast_ops;
648 default:
649 return &nft_hash_ops;
650 }
651 }
652
653 return &nft_rhash_ops;
654 }
655
656 static struct nft_set_type nft_hash_type __read_mostly = {
657 .select_ops = nft_hash_select_ops,
658 .owner = THIS_MODULE,
659 };
660
661 static int __init nft_hash_module_init(void)
662 {
663 return nft_register_set(&nft_hash_type);
664 }
665
666 static void __exit nft_hash_module_exit(void)
667 {
668 nft_unregister_set(&nft_hash_type);
669 }
670
671 module_init(nft_hash_module_init);
672 module_exit(nft_hash_module_exit);
673
674 MODULE_LICENSE("GPL");
675 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
676 MODULE_ALIAS_NFT_SET();
677
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