1 /*
2  * Copyright (c) 2008-2009 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/rbtree.h>
16 #include <linux/netlink.h>
17 #include <linux/netfilter.h>
18 #include <linux/netfilter/nf_tables.h>
19 #include <net/netfilter/nf_tables.h>
20 
21 struct nft_rbtree {
22 	struct rb_root		root;
23 	rwlock_t		lock;
24 	seqcount_t		count;
25 };
26 
27 struct nft_rbtree_elem {
28 	struct rb_node		node;
29 	struct nft_set_ext	ext;
30 };
31 
32 static bool nft_rbtree_interval_end(const struct nft_rbtree_elem *rbe)
33 {
34 	return nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) &&
35 	       (*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END);
36 }
37 
38 static bool nft_rbtree_equal(const struct nft_set *set, const void *this,
39 			     const struct nft_rbtree_elem *interval)
40 {
41 	return memcmp(this, nft_set_ext_key(&interval->ext), set->klen) == 0;
42 }
43 
44 static bool __nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
45 				const u32 *key, const struct nft_set_ext **ext,
46 				unsigned int seq)
47 {
48 	struct nft_rbtree *priv = nft_set_priv(set);
49 	const struct nft_rbtree_elem *rbe, *interval = NULL;
50 	u8 genmask = nft_genmask_cur(net);
51 	const struct rb_node *parent;
52 	const void *this;
53 	int d;
54 
55 	parent = rcu_dereference_raw(priv->root.rb_node);
56 	while (parent != NULL) {
57 		if (read_seqcount_retry(&priv->count, seq))
58 			return false;
59 
60 		rbe = rb_entry(parent, struct nft_rbtree_elem, node);
61 
62 		this = nft_set_ext_key(&rbe->ext);
63 		d = memcmp(this, key, set->klen);
64 		if (d < 0) {
65 			parent = rcu_dereference_raw(parent->rb_left);
66 			if (interval &&
67 			    nft_rbtree_equal(set, this, interval) &&
68 			    nft_rbtree_interval_end(this) &&
69 			    !nft_rbtree_interval_end(interval))
70 				continue;
71 			interval = rbe;
72 		} else if (d > 0)
73 			parent = rcu_dereference_raw(parent->rb_right);
74 		else {
75 			if (!nft_set_elem_active(&rbe->ext, genmask)) {
76 				parent = rcu_dereference_raw(parent->rb_left);
77 				continue;
78 			}
79 			if (nft_rbtree_interval_end(rbe))
80 				goto out;
81 
82 			*ext = &rbe->ext;
83 			return true;
84 		}
85 	}
86 
87 	if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
88 	    nft_set_elem_active(&interval->ext, genmask) &&
89 	    !nft_rbtree_interval_end(interval)) {
90 		*ext = &interval->ext;
91 		return true;
92 	}
93 out:
94 	return false;
95 }
96 
97 static bool nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
98 			      const u32 *key, const struct nft_set_ext **ext)
99 {
100 	struct nft_rbtree *priv = nft_set_priv(set);
101 	unsigned int seq = read_seqcount_begin(&priv->count);
102 	bool ret;
103 
104 	ret = __nft_rbtree_lookup(net, set, key, ext, seq);
105 	if (ret || !read_seqcount_retry(&priv->count, seq))
106 		return ret;
107 
108 	read_lock_bh(&priv->lock);
109 	seq = read_seqcount_begin(&priv->count);
110 	ret = __nft_rbtree_lookup(net, set, key, ext, seq);
111 	read_unlock_bh(&priv->lock);
112 
113 	return ret;
114 }
115 
116 static bool __nft_rbtree_get(const struct net *net, const struct nft_set *set,
117 			     const u32 *key, struct nft_rbtree_elem **elem,
118 			     unsigned int seq, unsigned int flags, u8 genmask)
119 {
120 	struct nft_rbtree_elem *rbe, *interval = NULL;
121 	struct nft_rbtree *priv = nft_set_priv(set);
122 	const struct rb_node *parent;
123 	const void *this;
124 	int d;
125 
126 	parent = rcu_dereference_raw(priv->root.rb_node);
127 	while (parent != NULL) {
128 		if (read_seqcount_retry(&priv->count, seq))
129 			return false;
130 
131 		rbe = rb_entry(parent, struct nft_rbtree_elem, node);
132 
133 		this = nft_set_ext_key(&rbe->ext);
134 		d = memcmp(this, key, set->klen);
135 		if (d < 0) {
136 			parent = rcu_dereference_raw(parent->rb_left);
137 			interval = rbe;
138 		} else if (d > 0) {
139 			parent = rcu_dereference_raw(parent->rb_right);
140 		} else {
141 			if (!nft_set_elem_active(&rbe->ext, genmask))
142 				parent = rcu_dereference_raw(parent->rb_left);
143 
144 			if (!nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) ||
145 			    (*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END) ==
146 			    (flags & NFT_SET_ELEM_INTERVAL_END)) {
147 				*elem = rbe;
148 				return true;
149 			}
150 			return false;
151 		}
152 	}
153 
154 	if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
155 	    nft_set_elem_active(&interval->ext, genmask) &&
156 	    !nft_rbtree_interval_end(interval)) {
157 		*elem = interval;
158 		return true;
159 	}
160 
161 	return false;
162 }
163 
164 static void *nft_rbtree_get(const struct net *net, const struct nft_set *set,
165 			    const struct nft_set_elem *elem, unsigned int flags)
166 {
167 	struct nft_rbtree *priv = nft_set_priv(set);
168 	unsigned int seq = read_seqcount_begin(&priv->count);
169 	struct nft_rbtree_elem *rbe = ERR_PTR(-ENOENT);
170 	const u32 *key = (const u32 *)&elem->key.val;
171 	u8 genmask = nft_genmask_cur(net);
172 	bool ret;
173 
174 	ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
175 	if (ret || !read_seqcount_retry(&priv->count, seq))
176 		return rbe;
177 
178 	read_lock_bh(&priv->lock);
179 	seq = read_seqcount_begin(&priv->count);
180 	ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
181 	if (!ret)
182 		rbe = ERR_PTR(-ENOENT);
183 	read_unlock_bh(&priv->lock);
184 
185 	return rbe;
186 }
187 
188 static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
189 			       struct nft_rbtree_elem *new,
190 			       struct nft_set_ext **ext)
191 {
192 	struct nft_rbtree *priv = nft_set_priv(set);
193 	u8 genmask = nft_genmask_next(net);
194 	struct nft_rbtree_elem *rbe;
195 	struct rb_node *parent, **p;
196 	int d;
197 
198 	parent = NULL;
199 	p = &priv->root.rb_node;
200 	while (*p != NULL) {
201 		parent = *p;
202 		rbe = rb_entry(parent, struct nft_rbtree_elem, node);
203 		d = memcmp(nft_set_ext_key(&rbe->ext),
204 			   nft_set_ext_key(&new->ext),
205 			   set->klen);
206 		if (d < 0)
207 			p = &parent->rb_left;
208 		else if (d > 0)
209 			p = &parent->rb_right;
210 		else {
211 			if (nft_rbtree_interval_end(rbe) &&
212 			    !nft_rbtree_interval_end(new)) {
213 				p = &parent->rb_left;
214 			} else if (!nft_rbtree_interval_end(rbe) &&
215 				   nft_rbtree_interval_end(new)) {
216 				p = &parent->rb_right;
217 			} else if (nft_set_elem_active(&rbe->ext, genmask)) {
218 				*ext = &rbe->ext;
219 				return -EEXIST;
220 			} else {
221 				p = &parent->rb_left;
222 			}
223 		}
224 	}
225 	rb_link_node_rcu(&new->node, parent, p);
226 	rb_insert_color(&new->node, &priv->root);
227 	return 0;
228 }
229 
230 static int nft_rbtree_insert(const struct net *net, const struct nft_set *set,
231 			     const struct nft_set_elem *elem,
232 			     struct nft_set_ext **ext)
233 {
234 	struct nft_rbtree *priv = nft_set_priv(set);
235 	struct nft_rbtree_elem *rbe = elem->priv;
236 	int err;
237 
238 	write_lock_bh(&priv->lock);
239 	write_seqcount_begin(&priv->count);
240 	err = __nft_rbtree_insert(net, set, rbe, ext);
241 	write_seqcount_end(&priv->count);
242 	write_unlock_bh(&priv->lock);
243 
244 	return err;
245 }
246 
247 static void nft_rbtree_remove(const struct net *net,
248 			      const struct nft_set *set,
249 			      const struct nft_set_elem *elem)
250 {
251 	struct nft_rbtree *priv = nft_set_priv(set);
252 	struct nft_rbtree_elem *rbe = elem->priv;
253 
254 	write_lock_bh(&priv->lock);
255 	write_seqcount_begin(&priv->count);
256 	rb_erase(&rbe->node, &priv->root);
257 	write_seqcount_end(&priv->count);
258 	write_unlock_bh(&priv->lock);
259 }
260 
261 static void nft_rbtree_activate(const struct net *net,
262 				const struct nft_set *set,
263 				const struct nft_set_elem *elem)
264 {
265 	struct nft_rbtree_elem *rbe = elem->priv;
266 
267 	nft_set_elem_change_active(net, set, &rbe->ext);
268 }
269 
270 static bool nft_rbtree_flush(const struct net *net,
271 			     const struct nft_set *set, void *priv)
272 {
273 	struct nft_rbtree_elem *rbe = priv;
274 
275 	nft_set_elem_change_active(net, set, &rbe->ext);
276 	return true;
277 }
278 
279 static void *nft_rbtree_deactivate(const struct net *net,
280 				   const struct nft_set *set,
281 				   const struct nft_set_elem *elem)
282 {
283 	const struct nft_rbtree *priv = nft_set_priv(set);
284 	const struct rb_node *parent = priv->root.rb_node;
285 	struct nft_rbtree_elem *rbe, *this = elem->priv;
286 	u8 genmask = nft_genmask_next(net);
287 	int d;
288 
289 	while (parent != NULL) {
290 		rbe = rb_entry(parent, struct nft_rbtree_elem, node);
291 
292 		d = memcmp(nft_set_ext_key(&rbe->ext), &elem->key.val,
293 					   set->klen);
294 		if (d < 0)
295 			parent = parent->rb_left;
296 		else if (d > 0)
297 			parent = parent->rb_right;
298 		else {
299 			if (!nft_set_elem_active(&rbe->ext, genmask)) {
300 				parent = parent->rb_left;
301 				continue;
302 			}
303 			if (nft_rbtree_interval_end(rbe) &&
304 			    !nft_rbtree_interval_end(this)) {
305 				parent = parent->rb_left;
306 				continue;
307 			} else if (!nft_rbtree_interval_end(rbe) &&
308 				   nft_rbtree_interval_end(this)) {
309 				parent = parent->rb_right;
310 				continue;
311 			}
312 			nft_rbtree_flush(net, set, rbe);
313 			return rbe;
314 		}
315 	}
316 	return NULL;
317 }
318 
319 static void nft_rbtree_walk(const struct nft_ctx *ctx,
320 			    struct nft_set *set,
321 			    struct nft_set_iter *iter)
322 {
323 	struct nft_rbtree *priv = nft_set_priv(set);
324 	struct nft_rbtree_elem *rbe;
325 	struct nft_set_elem elem;
326 	struct rb_node *node;
327 
328 	read_lock_bh(&priv->lock);
329 	for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
330 		rbe = rb_entry(node, struct nft_rbtree_elem, node);
331 
332 		if (iter->count < iter->skip)
333 			goto cont;
334 		if (!nft_set_elem_active(&rbe->ext, iter->genmask))
335 			goto cont;
336 
337 		elem.priv = rbe;
338 
339 		iter->err = iter->fn(ctx, set, iter, &elem);
340 		if (iter->err < 0) {
341 			read_unlock_bh(&priv->lock);
342 			return;
343 		}
344 cont:
345 		iter->count++;
346 	}
347 	read_unlock_bh(&priv->lock);
348 }
349 
350 static unsigned int nft_rbtree_privsize(const struct nlattr * const nla[],
351 					const struct nft_set_desc *desc)
352 {
353 	return sizeof(struct nft_rbtree);
354 }
355 
356 static int nft_rbtree_init(const struct nft_set *set,
357 			   const struct nft_set_desc *desc,
358 			   const struct nlattr * const nla[])
359 {
360 	struct nft_rbtree *priv = nft_set_priv(set);
361 
362 	rwlock_init(&priv->lock);
363 	seqcount_init(&priv->count);
364 	priv->root = RB_ROOT;
365 	return 0;
366 }
367 
368 static void nft_rbtree_destroy(const struct nft_set *set)
369 {
370 	struct nft_rbtree *priv = nft_set_priv(set);
371 	struct nft_rbtree_elem *rbe;
372 	struct rb_node *node;
373 
374 	while ((node = priv->root.rb_node) != NULL) {
375 		rb_erase(node, &priv->root);
376 		rbe = rb_entry(node, struct nft_rbtree_elem, node);
377 		nft_set_elem_destroy(set, rbe, true);
378 	}
379 }
380 
381 static bool nft_rbtree_estimate(const struct nft_set_desc *desc, u32 features,
382 				struct nft_set_estimate *est)
383 {
384 	if (desc->size)
385 		est->size = sizeof(struct nft_rbtree) +
386 			    desc->size * sizeof(struct nft_rbtree_elem);
387 	else
388 		est->size = ~0;
389 
390 	est->lookup = NFT_SET_CLASS_O_LOG_N;
391 	est->space  = NFT_SET_CLASS_O_N;
392 
393 	return true;
394 }
395 
396 static struct nft_set_type nft_rbtree_type;
397 static struct nft_set_ops nft_rbtree_ops __read_mostly = {
398 	.type		= &nft_rbtree_type,
399 	.privsize	= nft_rbtree_privsize,
400 	.elemsize	= offsetof(struct nft_rbtree_elem, ext),
401 	.estimate	= nft_rbtree_estimate,
402 	.init		= nft_rbtree_init,
403 	.destroy	= nft_rbtree_destroy,
404 	.insert		= nft_rbtree_insert,
405 	.remove		= nft_rbtree_remove,
406 	.deactivate	= nft_rbtree_deactivate,
407 	.flush		= nft_rbtree_flush,
408 	.activate	= nft_rbtree_activate,
409 	.lookup		= nft_rbtree_lookup,
410 	.walk		= nft_rbtree_walk,
411 	.get		= nft_rbtree_get,
412 	.features	= NFT_SET_INTERVAL | NFT_SET_MAP | NFT_SET_OBJECT,
413 };
414 
415 static struct nft_set_type nft_rbtree_type __read_mostly = {
416 	.ops		= &nft_rbtree_ops,
417 	.owner		= THIS_MODULE,
418 };
419 
420 static int __init nft_rbtree_module_init(void)
421 {
422 	return nft_register_set(&nft_rbtree_type);
423 }
424 
425 static void __exit nft_rbtree_module_exit(void)
426 {
427 	nft_unregister_set(&nft_rbtree_type);
428 }
429 
430 module_init(nft_rbtree_module_init);
431 module_exit(nft_rbtree_module_exit);
432 
433 MODULE_LICENSE("GPL");
434 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
435 MODULE_ALIAS_NFT_SET();
436