1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
4  *
5  * Development of this code funded by Astaro AG (http://www.astaro.com/)
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/init.h>
10 #include <linux/module.h>
11 #include <linux/list.h>
12 #include <linux/rbtree.h>
13 #include <linux/netlink.h>
14 #include <linux/netfilter.h>
15 #include <linux/netfilter/nf_tables.h>
16 #include <net/netfilter/nf_tables_core.h>
17 
18 struct nft_rbtree {
19 	struct rb_root		root;
20 	rwlock_t		lock;
21 	seqcount_rwlock_t	count;
22 	struct delayed_work	gc_work;
23 };
24 
25 struct nft_rbtree_elem {
26 	struct rb_node		node;
27 	struct nft_set_ext	ext;
28 };
29 
nft_rbtree_interval_end(const struct nft_rbtree_elem * rbe)30 static bool nft_rbtree_interval_end(const struct nft_rbtree_elem *rbe)
31 {
32 	return nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) &&
33 	       (*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END);
34 }
35 
nft_rbtree_interval_start(const struct nft_rbtree_elem * rbe)36 static bool nft_rbtree_interval_start(const struct nft_rbtree_elem *rbe)
37 {
38 	return !nft_rbtree_interval_end(rbe);
39 }
40 
nft_rbtree_cmp(const struct nft_set * set,const struct nft_rbtree_elem * e1,const struct nft_rbtree_elem * e2)41 static int nft_rbtree_cmp(const struct nft_set *set,
42 			  const struct nft_rbtree_elem *e1,
43 			  const struct nft_rbtree_elem *e2)
44 {
45 	return memcmp(nft_set_ext_key(&e1->ext), nft_set_ext_key(&e2->ext),
46 		      set->klen);
47 }
48 
nft_rbtree_elem_expired(const struct nft_rbtree_elem * rbe)49 static bool nft_rbtree_elem_expired(const struct nft_rbtree_elem *rbe)
50 {
51 	return nft_set_elem_expired(&rbe->ext) ||
52 	       nft_set_elem_is_dead(&rbe->ext);
53 }
54 
__nft_rbtree_lookup(const struct net * net,const struct nft_set * set,const u32 * key,const struct nft_set_ext ** ext,unsigned int seq)55 static bool __nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
56 				const u32 *key, const struct nft_set_ext **ext,
57 				unsigned int seq)
58 {
59 	struct nft_rbtree *priv = nft_set_priv(set);
60 	const struct nft_rbtree_elem *rbe, *interval = NULL;
61 	u8 genmask = nft_genmask_cur(net);
62 	const struct rb_node *parent;
63 	int d;
64 
65 	parent = rcu_dereference_raw(priv->root.rb_node);
66 	while (parent != NULL) {
67 		if (read_seqcount_retry(&priv->count, seq))
68 			return false;
69 
70 		rbe = rb_entry(parent, struct nft_rbtree_elem, node);
71 
72 		d = memcmp(nft_set_ext_key(&rbe->ext), key, set->klen);
73 		if (d < 0) {
74 			parent = rcu_dereference_raw(parent->rb_left);
75 			if (interval &&
76 			    !nft_rbtree_cmp(set, rbe, interval) &&
77 			    nft_rbtree_interval_end(rbe) &&
78 			    nft_rbtree_interval_start(interval))
79 				continue;
80 			interval = rbe;
81 		} else if (d > 0)
82 			parent = rcu_dereference_raw(parent->rb_right);
83 		else {
84 			if (!nft_set_elem_active(&rbe->ext, genmask)) {
85 				parent = rcu_dereference_raw(parent->rb_left);
86 				continue;
87 			}
88 
89 			if (nft_rbtree_elem_expired(rbe))
90 				return false;
91 
92 			if (nft_rbtree_interval_end(rbe)) {
93 				if (nft_set_is_anonymous(set))
94 					return false;
95 				parent = rcu_dereference_raw(parent->rb_left);
96 				interval = NULL;
97 				continue;
98 			}
99 
100 			*ext = &rbe->ext;
101 			return true;
102 		}
103 	}
104 
105 	if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
106 	    nft_set_elem_active(&interval->ext, genmask) &&
107 	    !nft_rbtree_elem_expired(interval) &&
108 	    nft_rbtree_interval_start(interval)) {
109 		*ext = &interval->ext;
110 		return true;
111 	}
112 
113 	return false;
114 }
115 
116 INDIRECT_CALLABLE_SCOPE
nft_rbtree_lookup(const struct net * net,const struct nft_set * set,const u32 * key,const struct nft_set_ext ** ext)117 bool nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
118 		       const u32 *key, const struct nft_set_ext **ext)
119 {
120 	struct nft_rbtree *priv = nft_set_priv(set);
121 	unsigned int seq = read_seqcount_begin(&priv->count);
122 	bool ret;
123 
124 	ret = __nft_rbtree_lookup(net, set, key, ext, seq);
125 	if (ret || !read_seqcount_retry(&priv->count, seq))
126 		return ret;
127 
128 	read_lock_bh(&priv->lock);
129 	seq = read_seqcount_begin(&priv->count);
130 	ret = __nft_rbtree_lookup(net, set, key, ext, seq);
131 	read_unlock_bh(&priv->lock);
132 
133 	return ret;
134 }
135 
__nft_rbtree_get(const struct net * net,const struct nft_set * set,const u32 * key,struct nft_rbtree_elem ** elem,unsigned int seq,unsigned int flags,u8 genmask)136 static bool __nft_rbtree_get(const struct net *net, const struct nft_set *set,
137 			     const u32 *key, struct nft_rbtree_elem **elem,
138 			     unsigned int seq, unsigned int flags, u8 genmask)
139 {
140 	struct nft_rbtree_elem *rbe, *interval = NULL;
141 	struct nft_rbtree *priv = nft_set_priv(set);
142 	const struct rb_node *parent;
143 	const void *this;
144 	int d;
145 
146 	parent = rcu_dereference_raw(priv->root.rb_node);
147 	while (parent != NULL) {
148 		if (read_seqcount_retry(&priv->count, seq))
149 			return false;
150 
151 		rbe = rb_entry(parent, struct nft_rbtree_elem, node);
152 
153 		this = nft_set_ext_key(&rbe->ext);
154 		d = memcmp(this, key, set->klen);
155 		if (d < 0) {
156 			parent = rcu_dereference_raw(parent->rb_left);
157 			if (!(flags & NFT_SET_ELEM_INTERVAL_END))
158 				interval = rbe;
159 		} else if (d > 0) {
160 			parent = rcu_dereference_raw(parent->rb_right);
161 			if (flags & NFT_SET_ELEM_INTERVAL_END)
162 				interval = rbe;
163 		} else {
164 			if (!nft_set_elem_active(&rbe->ext, genmask)) {
165 				parent = rcu_dereference_raw(parent->rb_left);
166 				continue;
167 			}
168 
169 			if (nft_set_elem_expired(&rbe->ext))
170 				return false;
171 
172 			if (!nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) ||
173 			    (*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END) ==
174 			    (flags & NFT_SET_ELEM_INTERVAL_END)) {
175 				*elem = rbe;
176 				return true;
177 			}
178 
179 			if (nft_rbtree_interval_end(rbe))
180 				interval = NULL;
181 
182 			parent = rcu_dereference_raw(parent->rb_left);
183 		}
184 	}
185 
186 	if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
187 	    nft_set_elem_active(&interval->ext, genmask) &&
188 	    !nft_set_elem_expired(&interval->ext) &&
189 	    ((!nft_rbtree_interval_end(interval) &&
190 	      !(flags & NFT_SET_ELEM_INTERVAL_END)) ||
191 	     (nft_rbtree_interval_end(interval) &&
192 	      (flags & NFT_SET_ELEM_INTERVAL_END)))) {
193 		*elem = interval;
194 		return true;
195 	}
196 
197 	return false;
198 }
199 
nft_rbtree_get(const struct net * net,const struct nft_set * set,const struct nft_set_elem * elem,unsigned int flags)200 static void *nft_rbtree_get(const struct net *net, const struct nft_set *set,
201 			    const struct nft_set_elem *elem, unsigned int flags)
202 {
203 	struct nft_rbtree *priv = nft_set_priv(set);
204 	unsigned int seq = read_seqcount_begin(&priv->count);
205 	struct nft_rbtree_elem *rbe = ERR_PTR(-ENOENT);
206 	const u32 *key = (const u32 *)&elem->key.val;
207 	u8 genmask = nft_genmask_cur(net);
208 	bool ret;
209 
210 	ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
211 	if (ret || !read_seqcount_retry(&priv->count, seq))
212 		return rbe;
213 
214 	read_lock_bh(&priv->lock);
215 	seq = read_seqcount_begin(&priv->count);
216 	ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
217 	if (!ret)
218 		rbe = ERR_PTR(-ENOENT);
219 	read_unlock_bh(&priv->lock);
220 
221 	return rbe;
222 }
223 
nft_rbtree_gc_remove(struct net * net,struct nft_set * set,struct nft_rbtree * priv,struct nft_rbtree_elem * rbe)224 static void nft_rbtree_gc_remove(struct net *net, struct nft_set *set,
225 				 struct nft_rbtree *priv,
226 				 struct nft_rbtree_elem *rbe)
227 {
228 	struct nft_set_elem elem = {
229 		.priv	= rbe,
230 	};
231 
232 	nft_setelem_data_deactivate(net, set, &elem);
233 	rb_erase(&rbe->node, &priv->root);
234 }
235 
236 static const struct nft_rbtree_elem *
nft_rbtree_gc_elem(const struct nft_set * __set,struct nft_rbtree * priv,struct nft_rbtree_elem * rbe)237 nft_rbtree_gc_elem(const struct nft_set *__set, struct nft_rbtree *priv,
238 		   struct nft_rbtree_elem *rbe)
239 {
240 	struct nft_set *set = (struct nft_set *)__set;
241 	struct rb_node *prev = rb_prev(&rbe->node);
242 	struct net *net = read_pnet(&set->net);
243 	struct nft_rbtree_elem *rbe_prev;
244 	struct nft_trans_gc *gc;
245 
246 	gc = nft_trans_gc_alloc(set, 0, GFP_ATOMIC);
247 	if (!gc)
248 		return ERR_PTR(-ENOMEM);
249 
250 	/* search for end interval coming before this element.
251 	 * end intervals don't carry a timeout extension, they
252 	 * are coupled with the interval start element.
253 	 */
254 	while (prev) {
255 		rbe_prev = rb_entry(prev, struct nft_rbtree_elem, node);
256 		if (nft_rbtree_interval_end(rbe_prev) &&
257 		    nft_set_elem_active(&rbe_prev->ext, NFT_GENMASK_ANY))
258 			break;
259 
260 		prev = rb_prev(prev);
261 	}
262 
263 	rbe_prev = NULL;
264 	if (prev) {
265 		rbe_prev = rb_entry(prev, struct nft_rbtree_elem, node);
266 		nft_rbtree_gc_remove(net, set, priv, rbe_prev);
267 
268 		/* There is always room in this trans gc for this element,
269 		 * memory allocation never actually happens, hence, the warning
270 		 * splat in such case. No need to set NFT_SET_ELEM_DEAD_BIT,
271 		 * this is synchronous gc which never fails.
272 		 */
273 		gc = nft_trans_gc_queue_sync(gc, GFP_ATOMIC);
274 		if (WARN_ON_ONCE(!gc))
275 			return ERR_PTR(-ENOMEM);
276 
277 		nft_trans_gc_elem_add(gc, rbe_prev);
278 	}
279 
280 	nft_rbtree_gc_remove(net, set, priv, rbe);
281 	gc = nft_trans_gc_queue_sync(gc, GFP_ATOMIC);
282 	if (WARN_ON_ONCE(!gc))
283 		return ERR_PTR(-ENOMEM);
284 
285 	nft_trans_gc_elem_add(gc, rbe);
286 
287 	nft_trans_gc_queue_sync_done(gc);
288 
289 	return rbe_prev;
290 }
291 
nft_rbtree_update_first(const struct nft_set * set,struct nft_rbtree_elem * rbe,struct rb_node * first)292 static bool nft_rbtree_update_first(const struct nft_set *set,
293 				    struct nft_rbtree_elem *rbe,
294 				    struct rb_node *first)
295 {
296 	struct nft_rbtree_elem *first_elem;
297 
298 	first_elem = rb_entry(first, struct nft_rbtree_elem, node);
299 	/* this element is closest to where the new element is to be inserted:
300 	 * update the first element for the node list path.
301 	 */
302 	if (nft_rbtree_cmp(set, rbe, first_elem) < 0)
303 		return true;
304 
305 	return false;
306 }
307 
__nft_rbtree_insert(const struct net * net,const struct nft_set * set,struct nft_rbtree_elem * new,struct nft_set_ext ** ext)308 static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
309 			       struct nft_rbtree_elem *new,
310 			       struct nft_set_ext **ext)
311 {
312 	struct nft_rbtree_elem *rbe, *rbe_le = NULL, *rbe_ge = NULL;
313 	struct rb_node *node, *next, *parent, **p, *first = NULL;
314 	struct nft_rbtree *priv = nft_set_priv(set);
315 	u8 cur_genmask = nft_genmask_cur(net);
316 	u8 genmask = nft_genmask_next(net);
317 	int d;
318 
319 	/* Descend the tree to search for an existing element greater than the
320 	 * key value to insert that is greater than the new element. This is the
321 	 * first element to walk the ordered elements to find possible overlap.
322 	 */
323 	parent = NULL;
324 	p = &priv->root.rb_node;
325 	while (*p != NULL) {
326 		parent = *p;
327 		rbe = rb_entry(parent, struct nft_rbtree_elem, node);
328 		d = nft_rbtree_cmp(set, rbe, new);
329 
330 		if (d < 0) {
331 			p = &parent->rb_left;
332 		} else if (d > 0) {
333 			if (!first ||
334 			    nft_rbtree_update_first(set, rbe, first))
335 				first = &rbe->node;
336 
337 			p = &parent->rb_right;
338 		} else {
339 			if (nft_rbtree_interval_end(rbe))
340 				p = &parent->rb_left;
341 			else
342 				p = &parent->rb_right;
343 		}
344 	}
345 
346 	if (!first)
347 		first = rb_first(&priv->root);
348 
349 	/* Detect overlap by going through the list of valid tree nodes.
350 	 * Values stored in the tree are in reversed order, starting from
351 	 * highest to lowest value.
352 	 */
353 	for (node = first; node != NULL; node = next) {
354 		next = rb_next(node);
355 
356 		rbe = rb_entry(node, struct nft_rbtree_elem, node);
357 
358 		if (!nft_set_elem_active(&rbe->ext, genmask))
359 			continue;
360 
361 		/* perform garbage collection to avoid bogus overlap reports
362 		 * but skip new elements in this transaction.
363 		 */
364 		if (nft_set_elem_expired(&rbe->ext) &&
365 		    nft_set_elem_active(&rbe->ext, cur_genmask)) {
366 			const struct nft_rbtree_elem *removed_end;
367 
368 			removed_end = nft_rbtree_gc_elem(set, priv, rbe);
369 			if (IS_ERR(removed_end))
370 				return PTR_ERR(removed_end);
371 
372 			if (removed_end == rbe_le || removed_end == rbe_ge)
373 				return -EAGAIN;
374 
375 			continue;
376 		}
377 
378 		d = nft_rbtree_cmp(set, rbe, new);
379 		if (d == 0) {
380 			/* Matching end element: no need to look for an
381 			 * overlapping greater or equal element.
382 			 */
383 			if (nft_rbtree_interval_end(rbe)) {
384 				rbe_le = rbe;
385 				break;
386 			}
387 
388 			/* first element that is greater or equal to key value. */
389 			if (!rbe_ge) {
390 				rbe_ge = rbe;
391 				continue;
392 			}
393 
394 			/* this is a closer more or equal element, update it. */
395 			if (nft_rbtree_cmp(set, rbe_ge, new) != 0) {
396 				rbe_ge = rbe;
397 				continue;
398 			}
399 
400 			/* element is equal to key value, make sure flags are
401 			 * the same, an existing more or equal start element
402 			 * must not be replaced by more or equal end element.
403 			 */
404 			if ((nft_rbtree_interval_start(new) &&
405 			     nft_rbtree_interval_start(rbe_ge)) ||
406 			    (nft_rbtree_interval_end(new) &&
407 			     nft_rbtree_interval_end(rbe_ge))) {
408 				rbe_ge = rbe;
409 				continue;
410 			}
411 		} else if (d > 0) {
412 			/* annotate element greater than the new element. */
413 			rbe_ge = rbe;
414 			continue;
415 		} else if (d < 0) {
416 			/* annotate element less than the new element. */
417 			rbe_le = rbe;
418 			break;
419 		}
420 	}
421 
422 	/* - new start element matching existing start element: full overlap
423 	 *   reported as -EEXIST, cleared by caller if NLM_F_EXCL is not given.
424 	 */
425 	if (rbe_ge && !nft_rbtree_cmp(set, new, rbe_ge) &&
426 	    nft_rbtree_interval_start(rbe_ge) == nft_rbtree_interval_start(new)) {
427 		*ext = &rbe_ge->ext;
428 		return -EEXIST;
429 	}
430 
431 	/* - new end element matching existing end element: full overlap
432 	 *   reported as -EEXIST, cleared by caller if NLM_F_EXCL is not given.
433 	 */
434 	if (rbe_le && !nft_rbtree_cmp(set, new, rbe_le) &&
435 	    nft_rbtree_interval_end(rbe_le) == nft_rbtree_interval_end(new)) {
436 		*ext = &rbe_le->ext;
437 		return -EEXIST;
438 	}
439 
440 	/* - new start element with existing closest, less or equal key value
441 	 *   being a start element: partial overlap, reported as -ENOTEMPTY.
442 	 *   Anonymous sets allow for two consecutive start element since they
443 	 *   are constant, skip them to avoid bogus overlap reports.
444 	 */
445 	if (!nft_set_is_anonymous(set) && rbe_le &&
446 	    nft_rbtree_interval_start(rbe_le) && nft_rbtree_interval_start(new))
447 		return -ENOTEMPTY;
448 
449 	/* - new end element with existing closest, less or equal key value
450 	 *   being a end element: partial overlap, reported as -ENOTEMPTY.
451 	 */
452 	if (rbe_le &&
453 	    nft_rbtree_interval_end(rbe_le) && nft_rbtree_interval_end(new))
454 		return -ENOTEMPTY;
455 
456 	/* - new end element with existing closest, greater or equal key value
457 	 *   being an end element: partial overlap, reported as -ENOTEMPTY
458 	 */
459 	if (rbe_ge &&
460 	    nft_rbtree_interval_end(rbe_ge) && nft_rbtree_interval_end(new))
461 		return -ENOTEMPTY;
462 
463 	/* Accepted element: pick insertion point depending on key value */
464 	parent = NULL;
465 	p = &priv->root.rb_node;
466 	while (*p != NULL) {
467 		parent = *p;
468 		rbe = rb_entry(parent, struct nft_rbtree_elem, node);
469 		d = nft_rbtree_cmp(set, rbe, new);
470 
471 		if (d < 0)
472 			p = &parent->rb_left;
473 		else if (d > 0)
474 			p = &parent->rb_right;
475 		else if (nft_rbtree_interval_end(rbe))
476 			p = &parent->rb_left;
477 		else
478 			p = &parent->rb_right;
479 	}
480 
481 	rb_link_node_rcu(&new->node, parent, p);
482 	rb_insert_color(&new->node, &priv->root);
483 	return 0;
484 }
485 
nft_rbtree_insert(const struct net * net,const struct nft_set * set,const struct nft_set_elem * elem,struct nft_set_ext ** ext)486 static int nft_rbtree_insert(const struct net *net, const struct nft_set *set,
487 			     const struct nft_set_elem *elem,
488 			     struct nft_set_ext **ext)
489 {
490 	struct nft_rbtree *priv = nft_set_priv(set);
491 	struct nft_rbtree_elem *rbe = elem->priv;
492 	int err;
493 
494 	do {
495 		if (fatal_signal_pending(current))
496 			return -EINTR;
497 
498 		cond_resched();
499 
500 		write_lock_bh(&priv->lock);
501 		write_seqcount_begin(&priv->count);
502 		err = __nft_rbtree_insert(net, set, rbe, ext);
503 		write_seqcount_end(&priv->count);
504 		write_unlock_bh(&priv->lock);
505 	} while (err == -EAGAIN);
506 
507 	return err;
508 }
509 
nft_rbtree_remove(const struct net * net,const struct nft_set * set,const struct nft_set_elem * elem)510 static void nft_rbtree_remove(const struct net *net,
511 			      const struct nft_set *set,
512 			      const struct nft_set_elem *elem)
513 {
514 	struct nft_rbtree *priv = nft_set_priv(set);
515 	struct nft_rbtree_elem *rbe = elem->priv;
516 
517 	write_lock_bh(&priv->lock);
518 	write_seqcount_begin(&priv->count);
519 	rb_erase(&rbe->node, &priv->root);
520 	write_seqcount_end(&priv->count);
521 	write_unlock_bh(&priv->lock);
522 }
523 
nft_rbtree_activate(const struct net * net,const struct nft_set * set,const struct nft_set_elem * elem)524 static void nft_rbtree_activate(const struct net *net,
525 				const struct nft_set *set,
526 				const struct nft_set_elem *elem)
527 {
528 	struct nft_rbtree_elem *rbe = elem->priv;
529 
530 	nft_set_elem_change_active(net, set, &rbe->ext);
531 }
532 
nft_rbtree_flush(const struct net * net,const struct nft_set * set,void * priv)533 static bool nft_rbtree_flush(const struct net *net,
534 			     const struct nft_set *set, void *priv)
535 {
536 	struct nft_rbtree_elem *rbe = priv;
537 
538 	nft_set_elem_change_active(net, set, &rbe->ext);
539 
540 	return true;
541 }
542 
nft_rbtree_deactivate(const struct net * net,const struct nft_set * set,const struct nft_set_elem * elem)543 static void *nft_rbtree_deactivate(const struct net *net,
544 				   const struct nft_set *set,
545 				   const struct nft_set_elem *elem)
546 {
547 	const struct nft_rbtree *priv = nft_set_priv(set);
548 	const struct rb_node *parent = priv->root.rb_node;
549 	struct nft_rbtree_elem *rbe, *this = elem->priv;
550 	u8 genmask = nft_genmask_next(net);
551 	int d;
552 
553 	while (parent != NULL) {
554 		rbe = rb_entry(parent, struct nft_rbtree_elem, node);
555 
556 		d = memcmp(nft_set_ext_key(&rbe->ext), &elem->key.val,
557 					   set->klen);
558 		if (d < 0)
559 			parent = parent->rb_left;
560 		else if (d > 0)
561 			parent = parent->rb_right;
562 		else {
563 			if (nft_rbtree_interval_end(rbe) &&
564 			    nft_rbtree_interval_start(this)) {
565 				parent = parent->rb_left;
566 				continue;
567 			} else if (nft_rbtree_interval_start(rbe) &&
568 				   nft_rbtree_interval_end(this)) {
569 				parent = parent->rb_right;
570 				continue;
571 			} else if (nft_set_elem_expired(&rbe->ext)) {
572 				break;
573 			} else if (!nft_set_elem_active(&rbe->ext, genmask)) {
574 				parent = parent->rb_left;
575 				continue;
576 			}
577 			nft_rbtree_flush(net, set, rbe);
578 			return rbe;
579 		}
580 	}
581 	return NULL;
582 }
583 
nft_rbtree_walk(const struct nft_ctx * ctx,struct nft_set * set,struct nft_set_iter * iter)584 static void nft_rbtree_walk(const struct nft_ctx *ctx,
585 			    struct nft_set *set,
586 			    struct nft_set_iter *iter)
587 {
588 	struct nft_rbtree *priv = nft_set_priv(set);
589 	struct nft_rbtree_elem *rbe;
590 	struct nft_set_elem elem;
591 	struct rb_node *node;
592 
593 	read_lock_bh(&priv->lock);
594 	for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
595 		rbe = rb_entry(node, struct nft_rbtree_elem, node);
596 
597 		if (iter->count < iter->skip)
598 			goto cont;
599 		if (!nft_set_elem_active(&rbe->ext, iter->genmask))
600 			goto cont;
601 
602 		elem.priv = rbe;
603 
604 		iter->err = iter->fn(ctx, set, iter, &elem);
605 		if (iter->err < 0) {
606 			read_unlock_bh(&priv->lock);
607 			return;
608 		}
609 cont:
610 		iter->count++;
611 	}
612 	read_unlock_bh(&priv->lock);
613 }
614 
nft_rbtree_gc(struct work_struct * work)615 static void nft_rbtree_gc(struct work_struct *work)
616 {
617 	struct nft_rbtree_elem *rbe, *rbe_end = NULL;
618 	struct nftables_pernet *nft_net;
619 	struct nft_rbtree *priv;
620 	struct nft_trans_gc *gc;
621 	struct rb_node *node;
622 	struct nft_set *set;
623 	unsigned int gc_seq;
624 	struct net *net;
625 
626 	priv = container_of(work, struct nft_rbtree, gc_work.work);
627 	set  = nft_set_container_of(priv);
628 	net  = read_pnet(&set->net);
629 	nft_net = nft_pernet(net);
630 	gc_seq  = READ_ONCE(nft_net->gc_seq);
631 
632 	if (nft_set_gc_is_pending(set))
633 		goto done;
634 
635 	gc = nft_trans_gc_alloc(set, gc_seq, GFP_KERNEL);
636 	if (!gc)
637 		goto done;
638 
639 	read_lock_bh(&priv->lock);
640 	for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
641 
642 		/* Ruleset has been updated, try later. */
643 		if (READ_ONCE(nft_net->gc_seq) != gc_seq) {
644 			nft_trans_gc_destroy(gc);
645 			gc = NULL;
646 			goto try_later;
647 		}
648 
649 		rbe = rb_entry(node, struct nft_rbtree_elem, node);
650 
651 		if (nft_set_elem_is_dead(&rbe->ext))
652 			goto dead_elem;
653 
654 		/* elements are reversed in the rbtree for historical reasons,
655 		 * from highest to lowest value, that is why end element is
656 		 * always visited before the start element.
657 		 */
658 		if (nft_rbtree_interval_end(rbe)) {
659 			rbe_end = rbe;
660 			continue;
661 		}
662 		if (!nft_set_elem_expired(&rbe->ext))
663 			continue;
664 
665 		nft_set_elem_dead(&rbe->ext);
666 
667 		if (!rbe_end)
668 			continue;
669 
670 		nft_set_elem_dead(&rbe_end->ext);
671 
672 		gc = nft_trans_gc_queue_async(gc, gc_seq, GFP_ATOMIC);
673 		if (!gc)
674 			goto try_later;
675 
676 		nft_trans_gc_elem_add(gc, rbe_end);
677 		rbe_end = NULL;
678 dead_elem:
679 		gc = nft_trans_gc_queue_async(gc, gc_seq, GFP_ATOMIC);
680 		if (!gc)
681 			goto try_later;
682 
683 		nft_trans_gc_elem_add(gc, rbe);
684 	}
685 
686 	gc = nft_trans_gc_catchall_async(gc, gc_seq);
687 
688 try_later:
689 	read_unlock_bh(&priv->lock);
690 
691 	if (gc)
692 		nft_trans_gc_queue_async_done(gc);
693 done:
694 	queue_delayed_work(system_power_efficient_wq, &priv->gc_work,
695 			   nft_set_gc_interval(set));
696 }
697 
nft_rbtree_privsize(const struct nlattr * const nla[],const struct nft_set_desc * desc)698 static u64 nft_rbtree_privsize(const struct nlattr * const nla[],
699 			       const struct nft_set_desc *desc)
700 {
701 	return sizeof(struct nft_rbtree);
702 }
703 
nft_rbtree_init(const struct nft_set * set,const struct nft_set_desc * desc,const struct nlattr * const nla[])704 static int nft_rbtree_init(const struct nft_set *set,
705 			   const struct nft_set_desc *desc,
706 			   const struct nlattr * const nla[])
707 {
708 	struct nft_rbtree *priv = nft_set_priv(set);
709 
710 	rwlock_init(&priv->lock);
711 	seqcount_rwlock_init(&priv->count, &priv->lock);
712 	priv->root = RB_ROOT;
713 
714 	INIT_DEFERRABLE_WORK(&priv->gc_work, nft_rbtree_gc);
715 	if (set->flags & NFT_SET_TIMEOUT)
716 		queue_delayed_work(system_power_efficient_wq, &priv->gc_work,
717 				   nft_set_gc_interval(set));
718 
719 	return 0;
720 }
721 
nft_rbtree_destroy(const struct nft_ctx * ctx,const struct nft_set * set)722 static void nft_rbtree_destroy(const struct nft_ctx *ctx,
723 			       const struct nft_set *set)
724 {
725 	struct nft_rbtree *priv = nft_set_priv(set);
726 	struct nft_rbtree_elem *rbe;
727 	struct rb_node *node;
728 
729 	cancel_delayed_work_sync(&priv->gc_work);
730 	rcu_barrier();
731 	while ((node = priv->root.rb_node) != NULL) {
732 		rb_erase(node, &priv->root);
733 		rbe = rb_entry(node, struct nft_rbtree_elem, node);
734 		nf_tables_set_elem_destroy(ctx, set, rbe);
735 	}
736 }
737 
nft_rbtree_estimate(const struct nft_set_desc * desc,u32 features,struct nft_set_estimate * est)738 static bool nft_rbtree_estimate(const struct nft_set_desc *desc, u32 features,
739 				struct nft_set_estimate *est)
740 {
741 	if (desc->field_count > 1)
742 		return false;
743 
744 	if (desc->size)
745 		est->size = sizeof(struct nft_rbtree) +
746 			    desc->size * sizeof(struct nft_rbtree_elem);
747 	else
748 		est->size = ~0;
749 
750 	est->lookup = NFT_SET_CLASS_O_LOG_N;
751 	est->space  = NFT_SET_CLASS_O_N;
752 
753 	return true;
754 }
755 
756 const struct nft_set_type nft_set_rbtree_type = {
757 	.features	= NFT_SET_INTERVAL | NFT_SET_MAP | NFT_SET_OBJECT | NFT_SET_TIMEOUT,
758 	.ops		= {
759 		.privsize	= nft_rbtree_privsize,
760 		.elemsize	= offsetof(struct nft_rbtree_elem, ext),
761 		.estimate	= nft_rbtree_estimate,
762 		.init		= nft_rbtree_init,
763 		.destroy	= nft_rbtree_destroy,
764 		.insert		= nft_rbtree_insert,
765 		.remove		= nft_rbtree_remove,
766 		.deactivate	= nft_rbtree_deactivate,
767 		.flush		= nft_rbtree_flush,
768 		.activate	= nft_rbtree_activate,
769 		.lookup		= nft_rbtree_lookup,
770 		.walk		= nft_rbtree_walk,
771 		.get		= nft_rbtree_get,
772 	},
773 };
774