xref: /openbmc/linux/net/openvswitch/flow_table.c (revision 206e8c00752fbe9cc463184236ac64b2a532cda5)
1 /*
2  * Copyright (c) 2007-2014 Nicira, Inc.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of version 2 of the GNU General Public
6  * License as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful, but
9  * WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public License
14  * along with this program; if not, write to the Free Software
15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
16  * 02110-1301, USA
17  */
18 
19 #include "flow.h"
20 #include "datapath.h"
21 #include "flow_netlink.h"
22 #include <linux/uaccess.h>
23 #include <linux/netdevice.h>
24 #include <linux/etherdevice.h>
25 #include <linux/if_ether.h>
26 #include <linux/if_vlan.h>
27 #include <net/llc_pdu.h>
28 #include <linux/kernel.h>
29 #include <linux/jhash.h>
30 #include <linux/jiffies.h>
31 #include <linux/llc.h>
32 #include <linux/module.h>
33 #include <linux/in.h>
34 #include <linux/rcupdate.h>
35 #include <linux/if_arp.h>
36 #include <linux/ip.h>
37 #include <linux/ipv6.h>
38 #include <linux/sctp.h>
39 #include <linux/tcp.h>
40 #include <linux/udp.h>
41 #include <linux/icmp.h>
42 #include <linux/icmpv6.h>
43 #include <linux/rculist.h>
44 #include <net/ip.h>
45 #include <net/ipv6.h>
46 #include <net/ndisc.h>
47 
48 #define TBL_MIN_BUCKETS		1024
49 #define REHASH_INTERVAL		(10 * 60 * HZ)
50 
51 static struct kmem_cache *flow_cache;
52 struct kmem_cache *flow_stats_cache __read_mostly;
53 
54 static u16 range_n_bytes(const struct sw_flow_key_range *range)
55 {
56 	return range->end - range->start;
57 }
58 
59 void ovs_flow_mask_key(struct sw_flow_key *dst, const struct sw_flow_key *src,
60 		       const struct sw_flow_mask *mask)
61 {
62 	const long *m = (const long *)((const u8 *)&mask->key +
63 				mask->range.start);
64 	const long *s = (const long *)((const u8 *)src +
65 				mask->range.start);
66 	long *d = (long *)((u8 *)dst + mask->range.start);
67 	int i;
68 
69 	/* The memory outside of the 'mask->range' are not set since
70 	 * further operations on 'dst' only uses contents within
71 	 * 'mask->range'.
72 	 */
73 	for (i = 0; i < range_n_bytes(&mask->range); i += sizeof(long))
74 		*d++ = *s++ & *m++;
75 }
76 
77 struct sw_flow *ovs_flow_alloc(void)
78 {
79 	struct sw_flow *flow;
80 	struct flow_stats *stats;
81 	int node;
82 
83 	flow = kmem_cache_alloc(flow_cache, GFP_KERNEL);
84 	if (!flow)
85 		return ERR_PTR(-ENOMEM);
86 
87 	flow->sf_acts = NULL;
88 	flow->mask = NULL;
89 	flow->id.unmasked_key = NULL;
90 	flow->id.ufid_len = 0;
91 	flow->stats_last_writer = NUMA_NO_NODE;
92 
93 	/* Initialize the default stat node. */
94 	stats = kmem_cache_alloc_node(flow_stats_cache,
95 				      GFP_KERNEL | __GFP_ZERO, 0);
96 	if (!stats)
97 		goto err;
98 
99 	spin_lock_init(&stats->lock);
100 
101 	RCU_INIT_POINTER(flow->stats[0], stats);
102 
103 	for_each_node(node)
104 		if (node != 0)
105 			RCU_INIT_POINTER(flow->stats[node], NULL);
106 
107 	return flow;
108 err:
109 	kmem_cache_free(flow_cache, flow);
110 	return ERR_PTR(-ENOMEM);
111 }
112 
113 int ovs_flow_tbl_count(const struct flow_table *table)
114 {
115 	return table->count;
116 }
117 
118 static struct flex_array *alloc_buckets(unsigned int n_buckets)
119 {
120 	struct flex_array *buckets;
121 	int i, err;
122 
123 	buckets = flex_array_alloc(sizeof(struct hlist_head),
124 				   n_buckets, GFP_KERNEL);
125 	if (!buckets)
126 		return NULL;
127 
128 	err = flex_array_prealloc(buckets, 0, n_buckets, GFP_KERNEL);
129 	if (err) {
130 		flex_array_free(buckets);
131 		return NULL;
132 	}
133 
134 	for (i = 0; i < n_buckets; i++)
135 		INIT_HLIST_HEAD((struct hlist_head *)
136 					flex_array_get(buckets, i));
137 
138 	return buckets;
139 }
140 
141 static void flow_free(struct sw_flow *flow)
142 {
143 	int node;
144 
145 	if (ovs_identifier_is_key(&flow->id))
146 		kfree(flow->id.unmasked_key);
147 	if (flow->sf_acts)
148 		ovs_nla_free_flow_actions((struct sw_flow_actions __force *)flow->sf_acts);
149 	for_each_node(node)
150 		if (flow->stats[node])
151 			kmem_cache_free(flow_stats_cache,
152 					(struct flow_stats __force *)flow->stats[node]);
153 	kmem_cache_free(flow_cache, flow);
154 }
155 
156 static void rcu_free_flow_callback(struct rcu_head *rcu)
157 {
158 	struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu);
159 
160 	flow_free(flow);
161 }
162 
163 void ovs_flow_free(struct sw_flow *flow, bool deferred)
164 {
165 	if (!flow)
166 		return;
167 
168 	if (deferred)
169 		call_rcu(&flow->rcu, rcu_free_flow_callback);
170 	else
171 		flow_free(flow);
172 }
173 
174 static void free_buckets(struct flex_array *buckets)
175 {
176 	flex_array_free(buckets);
177 }
178 
179 
180 static void __table_instance_destroy(struct table_instance *ti)
181 {
182 	free_buckets(ti->buckets);
183 	kfree(ti);
184 }
185 
186 static struct table_instance *table_instance_alloc(int new_size)
187 {
188 	struct table_instance *ti = kmalloc(sizeof(*ti), GFP_KERNEL);
189 
190 	if (!ti)
191 		return NULL;
192 
193 	ti->buckets = alloc_buckets(new_size);
194 
195 	if (!ti->buckets) {
196 		kfree(ti);
197 		return NULL;
198 	}
199 	ti->n_buckets = new_size;
200 	ti->node_ver = 0;
201 	ti->keep_flows = false;
202 	get_random_bytes(&ti->hash_seed, sizeof(u32));
203 
204 	return ti;
205 }
206 
207 int ovs_flow_tbl_init(struct flow_table *table)
208 {
209 	struct table_instance *ti, *ufid_ti;
210 
211 	ti = table_instance_alloc(TBL_MIN_BUCKETS);
212 
213 	if (!ti)
214 		return -ENOMEM;
215 
216 	ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS);
217 	if (!ufid_ti)
218 		goto free_ti;
219 
220 	rcu_assign_pointer(table->ti, ti);
221 	rcu_assign_pointer(table->ufid_ti, ufid_ti);
222 	INIT_LIST_HEAD(&table->mask_list);
223 	table->last_rehash = jiffies;
224 	table->count = 0;
225 	table->ufid_count = 0;
226 	return 0;
227 
228 free_ti:
229 	__table_instance_destroy(ti);
230 	return -ENOMEM;
231 }
232 
233 static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu)
234 {
235 	struct table_instance *ti = container_of(rcu, struct table_instance, rcu);
236 
237 	__table_instance_destroy(ti);
238 }
239 
240 static void table_instance_destroy(struct table_instance *ti,
241 				   struct table_instance *ufid_ti,
242 				   bool deferred)
243 {
244 	int i;
245 
246 	if (!ti)
247 		return;
248 
249 	BUG_ON(!ufid_ti);
250 	if (ti->keep_flows)
251 		goto skip_flows;
252 
253 	for (i = 0; i < ti->n_buckets; i++) {
254 		struct sw_flow *flow;
255 		struct hlist_head *head = flex_array_get(ti->buckets, i);
256 		struct hlist_node *n;
257 		int ver = ti->node_ver;
258 		int ufid_ver = ufid_ti->node_ver;
259 
260 		hlist_for_each_entry_safe(flow, n, head, flow_table.node[ver]) {
261 			hlist_del_rcu(&flow->flow_table.node[ver]);
262 			if (ovs_identifier_is_ufid(&flow->id))
263 				hlist_del_rcu(&flow->ufid_table.node[ufid_ver]);
264 			ovs_flow_free(flow, deferred);
265 		}
266 	}
267 
268 skip_flows:
269 	if (deferred) {
270 		call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
271 		call_rcu(&ufid_ti->rcu, flow_tbl_destroy_rcu_cb);
272 	} else {
273 		__table_instance_destroy(ti);
274 		__table_instance_destroy(ufid_ti);
275 	}
276 }
277 
278 /* No need for locking this function is called from RCU callback or
279  * error path.
280  */
281 void ovs_flow_tbl_destroy(struct flow_table *table)
282 {
283 	struct table_instance *ti = rcu_dereference_raw(table->ti);
284 	struct table_instance *ufid_ti = rcu_dereference_raw(table->ufid_ti);
285 
286 	table_instance_destroy(ti, ufid_ti, false);
287 }
288 
289 struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti,
290 				       u32 *bucket, u32 *last)
291 {
292 	struct sw_flow *flow;
293 	struct hlist_head *head;
294 	int ver;
295 	int i;
296 
297 	ver = ti->node_ver;
298 	while (*bucket < ti->n_buckets) {
299 		i = 0;
300 		head = flex_array_get(ti->buckets, *bucket);
301 		hlist_for_each_entry_rcu(flow, head, flow_table.node[ver]) {
302 			if (i < *last) {
303 				i++;
304 				continue;
305 			}
306 			*last = i + 1;
307 			return flow;
308 		}
309 		(*bucket)++;
310 		*last = 0;
311 	}
312 
313 	return NULL;
314 }
315 
316 static struct hlist_head *find_bucket(struct table_instance *ti, u32 hash)
317 {
318 	hash = jhash_1word(hash, ti->hash_seed);
319 	return flex_array_get(ti->buckets,
320 				(hash & (ti->n_buckets - 1)));
321 }
322 
323 static void table_instance_insert(struct table_instance *ti,
324 				  struct sw_flow *flow)
325 {
326 	struct hlist_head *head;
327 
328 	head = find_bucket(ti, flow->flow_table.hash);
329 	hlist_add_head_rcu(&flow->flow_table.node[ti->node_ver], head);
330 }
331 
332 static void ufid_table_instance_insert(struct table_instance *ti,
333 				       struct sw_flow *flow)
334 {
335 	struct hlist_head *head;
336 
337 	head = find_bucket(ti, flow->ufid_table.hash);
338 	hlist_add_head_rcu(&flow->ufid_table.node[ti->node_ver], head);
339 }
340 
341 static void flow_table_copy_flows(struct table_instance *old,
342 				  struct table_instance *new, bool ufid)
343 {
344 	int old_ver;
345 	int i;
346 
347 	old_ver = old->node_ver;
348 	new->node_ver = !old_ver;
349 
350 	/* Insert in new table. */
351 	for (i = 0; i < old->n_buckets; i++) {
352 		struct sw_flow *flow;
353 		struct hlist_head *head;
354 
355 		head = flex_array_get(old->buckets, i);
356 
357 		if (ufid)
358 			hlist_for_each_entry(flow, head,
359 					     ufid_table.node[old_ver])
360 				ufid_table_instance_insert(new, flow);
361 		else
362 			hlist_for_each_entry(flow, head,
363 					     flow_table.node[old_ver])
364 				table_instance_insert(new, flow);
365 	}
366 
367 	old->keep_flows = true;
368 }
369 
370 static struct table_instance *table_instance_rehash(struct table_instance *ti,
371 						    int n_buckets, bool ufid)
372 {
373 	struct table_instance *new_ti;
374 
375 	new_ti = table_instance_alloc(n_buckets);
376 	if (!new_ti)
377 		return NULL;
378 
379 	flow_table_copy_flows(ti, new_ti, ufid);
380 
381 	return new_ti;
382 }
383 
384 int ovs_flow_tbl_flush(struct flow_table *flow_table)
385 {
386 	struct table_instance *old_ti, *new_ti;
387 	struct table_instance *old_ufid_ti, *new_ufid_ti;
388 
389 	new_ti = table_instance_alloc(TBL_MIN_BUCKETS);
390 	if (!new_ti)
391 		return -ENOMEM;
392 	new_ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS);
393 	if (!new_ufid_ti)
394 		goto err_free_ti;
395 
396 	old_ti = ovsl_dereference(flow_table->ti);
397 	old_ufid_ti = ovsl_dereference(flow_table->ufid_ti);
398 
399 	rcu_assign_pointer(flow_table->ti, new_ti);
400 	rcu_assign_pointer(flow_table->ufid_ti, new_ufid_ti);
401 	flow_table->last_rehash = jiffies;
402 	flow_table->count = 0;
403 	flow_table->ufid_count = 0;
404 
405 	table_instance_destroy(old_ti, old_ufid_ti, true);
406 	return 0;
407 
408 err_free_ti:
409 	__table_instance_destroy(new_ti);
410 	return -ENOMEM;
411 }
412 
413 static u32 flow_hash(const struct sw_flow_key *key,
414 		     const struct sw_flow_key_range *range)
415 {
416 	int key_start = range->start;
417 	int key_end = range->end;
418 	const u32 *hash_key = (const u32 *)((const u8 *)key + key_start);
419 	int hash_u32s = (key_end - key_start) >> 2;
420 
421 	/* Make sure number of hash bytes are multiple of u32. */
422 	BUILD_BUG_ON(sizeof(long) % sizeof(u32));
423 
424 	return jhash2(hash_key, hash_u32s, 0);
425 }
426 
427 static int flow_key_start(const struct sw_flow_key *key)
428 {
429 	if (key->tun_key.u.ipv4.dst)
430 		return 0;
431 	else
432 		return rounddown(offsetof(struct sw_flow_key, phy),
433 					  sizeof(long));
434 }
435 
436 static bool cmp_key(const struct sw_flow_key *key1,
437 		    const struct sw_flow_key *key2,
438 		    int key_start, int key_end)
439 {
440 	const long *cp1 = (const long *)((const u8 *)key1 + key_start);
441 	const long *cp2 = (const long *)((const u8 *)key2 + key_start);
442 	long diffs = 0;
443 	int i;
444 
445 	for (i = key_start; i < key_end;  i += sizeof(long))
446 		diffs |= *cp1++ ^ *cp2++;
447 
448 	return diffs == 0;
449 }
450 
451 static bool flow_cmp_masked_key(const struct sw_flow *flow,
452 				const struct sw_flow_key *key,
453 				const struct sw_flow_key_range *range)
454 {
455 	return cmp_key(&flow->key, key, range->start, range->end);
456 }
457 
458 static bool ovs_flow_cmp_unmasked_key(const struct sw_flow *flow,
459 				      const struct sw_flow_match *match)
460 {
461 	struct sw_flow_key *key = match->key;
462 	int key_start = flow_key_start(key);
463 	int key_end = match->range.end;
464 
465 	BUG_ON(ovs_identifier_is_ufid(&flow->id));
466 	return cmp_key(flow->id.unmasked_key, key, key_start, key_end);
467 }
468 
469 static struct sw_flow *masked_flow_lookup(struct table_instance *ti,
470 					  const struct sw_flow_key *unmasked,
471 					  const struct sw_flow_mask *mask)
472 {
473 	struct sw_flow *flow;
474 	struct hlist_head *head;
475 	u32 hash;
476 	struct sw_flow_key masked_key;
477 
478 	ovs_flow_mask_key(&masked_key, unmasked, mask);
479 	hash = flow_hash(&masked_key, &mask->range);
480 	head = find_bucket(ti, hash);
481 	hlist_for_each_entry_rcu(flow, head, flow_table.node[ti->node_ver]) {
482 		if (flow->mask == mask && flow->flow_table.hash == hash &&
483 		    flow_cmp_masked_key(flow, &masked_key, &mask->range))
484 			return flow;
485 	}
486 	return NULL;
487 }
488 
489 struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
490 				    const struct sw_flow_key *key,
491 				    u32 *n_mask_hit)
492 {
493 	struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
494 	struct sw_flow_mask *mask;
495 	struct sw_flow *flow;
496 
497 	*n_mask_hit = 0;
498 	list_for_each_entry_rcu(mask, &tbl->mask_list, list) {
499 		(*n_mask_hit)++;
500 		flow = masked_flow_lookup(ti, key, mask);
501 		if (flow)  /* Found */
502 			return flow;
503 	}
504 	return NULL;
505 }
506 
507 struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl,
508 				    const struct sw_flow_key *key)
509 {
510 	u32 __always_unused n_mask_hit;
511 
512 	return ovs_flow_tbl_lookup_stats(tbl, key, &n_mask_hit);
513 }
514 
515 struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
516 					  const struct sw_flow_match *match)
517 {
518 	struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
519 	struct sw_flow_mask *mask;
520 	struct sw_flow *flow;
521 
522 	/* Always called under ovs-mutex. */
523 	list_for_each_entry(mask, &tbl->mask_list, list) {
524 		flow = masked_flow_lookup(ti, match->key, mask);
525 		if (flow && ovs_identifier_is_key(&flow->id) &&
526 		    ovs_flow_cmp_unmasked_key(flow, match))
527 			return flow;
528 	}
529 	return NULL;
530 }
531 
532 static u32 ufid_hash(const struct sw_flow_id *sfid)
533 {
534 	return jhash(sfid->ufid, sfid->ufid_len, 0);
535 }
536 
537 static bool ovs_flow_cmp_ufid(const struct sw_flow *flow,
538 			      const struct sw_flow_id *sfid)
539 {
540 	if (flow->id.ufid_len != sfid->ufid_len)
541 		return false;
542 
543 	return !memcmp(flow->id.ufid, sfid->ufid, sfid->ufid_len);
544 }
545 
546 bool ovs_flow_cmp(const struct sw_flow *flow, const struct sw_flow_match *match)
547 {
548 	if (ovs_identifier_is_ufid(&flow->id))
549 		return flow_cmp_masked_key(flow, match->key, &match->range);
550 
551 	return ovs_flow_cmp_unmasked_key(flow, match);
552 }
553 
554 struct sw_flow *ovs_flow_tbl_lookup_ufid(struct flow_table *tbl,
555 					 const struct sw_flow_id *ufid)
556 {
557 	struct table_instance *ti = rcu_dereference_ovsl(tbl->ufid_ti);
558 	struct sw_flow *flow;
559 	struct hlist_head *head;
560 	u32 hash;
561 
562 	hash = ufid_hash(ufid);
563 	head = find_bucket(ti, hash);
564 	hlist_for_each_entry_rcu(flow, head, ufid_table.node[ti->node_ver]) {
565 		if (flow->ufid_table.hash == hash &&
566 		    ovs_flow_cmp_ufid(flow, ufid))
567 			return flow;
568 	}
569 	return NULL;
570 }
571 
572 int ovs_flow_tbl_num_masks(const struct flow_table *table)
573 {
574 	struct sw_flow_mask *mask;
575 	int num = 0;
576 
577 	list_for_each_entry(mask, &table->mask_list, list)
578 		num++;
579 
580 	return num;
581 }
582 
583 static struct table_instance *table_instance_expand(struct table_instance *ti,
584 						    bool ufid)
585 {
586 	return table_instance_rehash(ti, ti->n_buckets * 2, ufid);
587 }
588 
589 /* Remove 'mask' from the mask list, if it is not needed any more. */
590 static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask)
591 {
592 	if (mask) {
593 		/* ovs-lock is required to protect mask-refcount and
594 		 * mask list.
595 		 */
596 		ASSERT_OVSL();
597 		BUG_ON(!mask->ref_count);
598 		mask->ref_count--;
599 
600 		if (!mask->ref_count) {
601 			list_del_rcu(&mask->list);
602 			kfree_rcu(mask, rcu);
603 		}
604 	}
605 }
606 
607 /* Must be called with OVS mutex held. */
608 void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow)
609 {
610 	struct table_instance *ti = ovsl_dereference(table->ti);
611 	struct table_instance *ufid_ti = ovsl_dereference(table->ufid_ti);
612 
613 	BUG_ON(table->count == 0);
614 	hlist_del_rcu(&flow->flow_table.node[ti->node_ver]);
615 	table->count--;
616 	if (ovs_identifier_is_ufid(&flow->id)) {
617 		hlist_del_rcu(&flow->ufid_table.node[ufid_ti->node_ver]);
618 		table->ufid_count--;
619 	}
620 
621 	/* RCU delete the mask. 'flow->mask' is not NULLed, as it should be
622 	 * accessible as long as the RCU read lock is held.
623 	 */
624 	flow_mask_remove(table, flow->mask);
625 }
626 
627 static struct sw_flow_mask *mask_alloc(void)
628 {
629 	struct sw_flow_mask *mask;
630 
631 	mask = kmalloc(sizeof(*mask), GFP_KERNEL);
632 	if (mask)
633 		mask->ref_count = 1;
634 
635 	return mask;
636 }
637 
638 static bool mask_equal(const struct sw_flow_mask *a,
639 		       const struct sw_flow_mask *b)
640 {
641 	const u8 *a_ = (const u8 *)&a->key + a->range.start;
642 	const u8 *b_ = (const u8 *)&b->key + b->range.start;
643 
644 	return  (a->range.end == b->range.end)
645 		&& (a->range.start == b->range.start)
646 		&& (memcmp(a_, b_, range_n_bytes(&a->range)) == 0);
647 }
648 
649 static struct sw_flow_mask *flow_mask_find(const struct flow_table *tbl,
650 					   const struct sw_flow_mask *mask)
651 {
652 	struct list_head *ml;
653 
654 	list_for_each(ml, &tbl->mask_list) {
655 		struct sw_flow_mask *m;
656 		m = container_of(ml, struct sw_flow_mask, list);
657 		if (mask_equal(mask, m))
658 			return m;
659 	}
660 
661 	return NULL;
662 }
663 
664 /* Add 'mask' into the mask list, if it is not already there. */
665 static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow,
666 			    const struct sw_flow_mask *new)
667 {
668 	struct sw_flow_mask *mask;
669 	mask = flow_mask_find(tbl, new);
670 	if (!mask) {
671 		/* Allocate a new mask if none exsits. */
672 		mask = mask_alloc();
673 		if (!mask)
674 			return -ENOMEM;
675 		mask->key = new->key;
676 		mask->range = new->range;
677 		list_add_rcu(&mask->list, &tbl->mask_list);
678 	} else {
679 		BUG_ON(!mask->ref_count);
680 		mask->ref_count++;
681 	}
682 
683 	flow->mask = mask;
684 	return 0;
685 }
686 
687 /* Must be called with OVS mutex held. */
688 static void flow_key_insert(struct flow_table *table, struct sw_flow *flow)
689 {
690 	struct table_instance *new_ti = NULL;
691 	struct table_instance *ti;
692 
693 	flow->flow_table.hash = flow_hash(&flow->key, &flow->mask->range);
694 	ti = ovsl_dereference(table->ti);
695 	table_instance_insert(ti, flow);
696 	table->count++;
697 
698 	/* Expand table, if necessary, to make room. */
699 	if (table->count > ti->n_buckets)
700 		new_ti = table_instance_expand(ti, false);
701 	else if (time_after(jiffies, table->last_rehash + REHASH_INTERVAL))
702 		new_ti = table_instance_rehash(ti, ti->n_buckets, false);
703 
704 	if (new_ti) {
705 		rcu_assign_pointer(table->ti, new_ti);
706 		call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
707 		table->last_rehash = jiffies;
708 	}
709 }
710 
711 /* Must be called with OVS mutex held. */
712 static void flow_ufid_insert(struct flow_table *table, struct sw_flow *flow)
713 {
714 	struct table_instance *ti;
715 
716 	flow->ufid_table.hash = ufid_hash(&flow->id);
717 	ti = ovsl_dereference(table->ufid_ti);
718 	ufid_table_instance_insert(ti, flow);
719 	table->ufid_count++;
720 
721 	/* Expand table, if necessary, to make room. */
722 	if (table->ufid_count > ti->n_buckets) {
723 		struct table_instance *new_ti;
724 
725 		new_ti = table_instance_expand(ti, true);
726 		if (new_ti) {
727 			rcu_assign_pointer(table->ufid_ti, new_ti);
728 			call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
729 		}
730 	}
731 }
732 
733 /* Must be called with OVS mutex held. */
734 int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow,
735 			const struct sw_flow_mask *mask)
736 {
737 	int err;
738 
739 	err = flow_mask_insert(table, flow, mask);
740 	if (err)
741 		return err;
742 	flow_key_insert(table, flow);
743 	if (ovs_identifier_is_ufid(&flow->id))
744 		flow_ufid_insert(table, flow);
745 
746 	return 0;
747 }
748 
749 /* Initializes the flow module.
750  * Returns zero if successful or a negative error code. */
751 int ovs_flow_init(void)
752 {
753 	BUILD_BUG_ON(__alignof__(struct sw_flow_key) % __alignof__(long));
754 	BUILD_BUG_ON(sizeof(struct sw_flow_key) % sizeof(long));
755 
756 	flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow)
757 				       + (nr_node_ids
758 					  * sizeof(struct flow_stats *)),
759 				       0, 0, NULL);
760 	if (flow_cache == NULL)
761 		return -ENOMEM;
762 
763 	flow_stats_cache
764 		= kmem_cache_create("sw_flow_stats", sizeof(struct flow_stats),
765 				    0, SLAB_HWCACHE_ALIGN, NULL);
766 	if (flow_stats_cache == NULL) {
767 		kmem_cache_destroy(flow_cache);
768 		flow_cache = NULL;
769 		return -ENOMEM;
770 	}
771 
772 	return 0;
773 }
774 
775 /* Uninitializes the flow module. */
776 void ovs_flow_exit(void)
777 {
778 	kmem_cache_destroy(flow_stats_cache);
779 	kmem_cache_destroy(flow_cache);
780 }
781