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