2 * Copyright (c) 2007-2013 Nicira, Inc.
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.
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.
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
21 #include <linux/uaccess.h>
22 #include <linux/netdevice.h>
23 #include <linux/etherdevice.h>
24 #include <linux/if_ether.h>
25 #include <linux/if_vlan.h>
26 #include <net/llc_pdu.h>
27 #include <linux/kernel.h>
28 #include <linux/hash.h>
29 #include <linux/jiffies.h>
30 #include <linux/llc.h>
31 #include <linux/module.h>
33 #include <linux/rcupdate.h>
34 #include <linux/if_arp.h>
36 #include <linux/ipv6.h>
37 #include <linux/sctp.h>
38 #include <linux/tcp.h>
39 #include <linux/udp.h>
40 #include <linux/icmp.h>
41 #include <linux/icmpv6.h>
42 #include <linux/rculist.h>
45 #include <net/ndisc.h>
49 #define TBL_MIN_BUCKETS 1024
50 #define REHASH_INTERVAL (10 * 60 * HZ)
52 #define MC_HASH_SHIFT 8
53 #define MC_HASH_ENTRIES (1u << MC_HASH_SHIFT)
54 #define MC_HASH_SEGS ((sizeof(uint32_t) * 8) / MC_HASH_SHIFT)
56 static struct kmem_cache *flow_cache;
57 struct kmem_cache *flow_stats_cache __read_mostly;
59 static u16 range_n_bytes(const struct sw_flow_key_range *range)
61 return range->end - range->start;
64 void ovs_flow_mask_key(struct sw_flow_key *dst, const struct sw_flow_key *src,
65 const struct sw_flow_mask *mask)
67 const long *m = (const long *)((const u8 *)&mask->key +
69 const long *s = (const long *)((const u8 *)src +
71 long *d = (long *)((u8 *)dst + mask->range.start);
74 /* The memory outside of the 'mask->range' are not set since
75 * further operations on 'dst' only uses contents within
78 for (i = 0; i < range_n_bytes(&mask->range); i += sizeof(long))
82 struct sw_flow *ovs_flow_alloc(void)
85 struct flow_stats *stats;
88 flow = kmem_cache_alloc(flow_cache, GFP_KERNEL);
90 return ERR_PTR(-ENOMEM);
94 flow->stats_last_writer = NUMA_NO_NODE;
96 /* Initialize the default stat node. */
97 stats = kmem_cache_alloc_node(flow_stats_cache,
98 GFP_KERNEL | __GFP_ZERO, 0);
102 spin_lock_init(&stats->lock);
104 RCU_INIT_POINTER(flow->stats[0], stats);
108 RCU_INIT_POINTER(flow->stats[node], NULL);
112 kmem_cache_free(flow_cache, flow);
113 return ERR_PTR(-ENOMEM);
116 int ovs_flow_tbl_count(struct flow_table *table)
121 static struct flex_array *alloc_buckets(unsigned int n_buckets)
123 struct flex_array *buckets;
126 buckets = flex_array_alloc(sizeof(struct hlist_head),
127 n_buckets, GFP_KERNEL);
131 err = flex_array_prealloc(buckets, 0, n_buckets, GFP_KERNEL);
133 flex_array_free(buckets);
137 for (i = 0; i < n_buckets; i++)
138 INIT_HLIST_HEAD((struct hlist_head *)
139 flex_array_get(buckets, i));
144 static void flow_free(struct sw_flow *flow)
148 kfree((struct sw_flow_actions __force *)flow->sf_acts);
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);
156 static void rcu_free_flow_callback(struct rcu_head *rcu)
158 struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu);
163 static void rcu_free_sw_flow_mask_cb(struct rcu_head *rcu)
165 struct sw_flow_mask *mask = container_of(rcu, struct sw_flow_mask, rcu);
170 void ovs_flow_free(struct sw_flow *flow, bool deferred)
176 call_rcu(&flow->rcu, rcu_free_flow_callback);
181 static void free_buckets(struct flex_array *buckets)
183 flex_array_free(buckets);
187 static void __table_instance_destroy(struct table_instance *ti)
189 free_buckets(ti->buckets);
193 static struct table_instance *table_instance_alloc(int new_size)
195 struct table_instance *ti = kmalloc(sizeof(*ti), GFP_KERNEL);
200 ti->buckets = alloc_buckets(new_size);
206 ti->n_buckets = new_size;
208 ti->keep_flows = false;
209 get_random_bytes(&ti->hash_seed, sizeof(u32));
214 int ovs_flow_tbl_init(struct flow_table *table)
216 struct table_instance *ti;
218 table->mask_cache = __alloc_percpu(sizeof(struct mask_cache_entry) *
219 MC_HASH_ENTRIES, __alignof__(struct mask_cache_entry));
220 if (!table->mask_cache)
223 ti = table_instance_alloc(TBL_MIN_BUCKETS);
225 free_percpu(table->mask_cache);
229 rcu_assign_pointer(table->ti, ti);
230 INIT_LIST_HEAD(&table->mask_list);
231 table->last_rehash = jiffies;
236 static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu)
238 struct table_instance *ti = container_of(rcu, struct table_instance, rcu);
240 __table_instance_destroy(ti);
243 static void table_instance_destroy(struct table_instance *ti, bool deferred)
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;
259 hlist_for_each_entry_safe(flow, n, head, hash_node[ver]) {
260 hlist_del_rcu(&flow->hash_node[ver]);
261 ovs_flow_free(flow, deferred);
267 call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
269 __table_instance_destroy(ti);
272 /* No need for locking this function is called from RCU callback or
274 void ovs_flow_tbl_destroy(struct flow_table *table)
276 struct table_instance *ti = (struct table_instance __force *)table->ti;
278 free_percpu(table->mask_cache);
279 table_instance_destroy(ti, false);
282 struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti,
283 u32 *bucket, u32 *last)
285 struct sw_flow *flow;
286 struct hlist_head *head;
291 while (*bucket < ti->n_buckets) {
293 head = flex_array_get(ti->buckets, *bucket);
294 hlist_for_each_entry_rcu(flow, head, hash_node[ver]) {
309 static struct hlist_head *find_bucket(struct table_instance *ti, u32 hash)
311 hash = jhash_1word(hash, ti->hash_seed);
312 return flex_array_get(ti->buckets,
313 (hash & (ti->n_buckets - 1)));
316 static void table_instance_insert(struct table_instance *ti, struct sw_flow *flow)
318 struct hlist_head *head;
320 head = find_bucket(ti, flow->hash);
321 hlist_add_head_rcu(&flow->hash_node[ti->node_ver], head);
324 static void flow_table_copy_flows(struct table_instance *old,
325 struct table_instance *new)
330 old_ver = old->node_ver;
331 new->node_ver = !old_ver;
333 /* Insert in new table. */
334 for (i = 0; i < old->n_buckets; i++) {
335 struct sw_flow *flow;
336 struct hlist_head *head;
338 head = flex_array_get(old->buckets, i);
340 hlist_for_each_entry(flow, head, hash_node[old_ver])
341 table_instance_insert(new, flow);
344 old->keep_flows = true;
347 static struct table_instance *table_instance_rehash(struct table_instance *ti,
350 struct table_instance *new_ti;
352 new_ti = table_instance_alloc(n_buckets);
356 flow_table_copy_flows(ti, new_ti);
361 int ovs_flow_tbl_flush(struct flow_table *flow_table)
363 struct table_instance *old_ti;
364 struct table_instance *new_ti;
366 old_ti = ovsl_dereference(flow_table->ti);
367 new_ti = table_instance_alloc(TBL_MIN_BUCKETS);
371 rcu_assign_pointer(flow_table->ti, new_ti);
372 flow_table->last_rehash = jiffies;
373 flow_table->count = 0;
375 table_instance_destroy(old_ti, true);
379 static u32 flow_hash(const struct sw_flow_key *key, int key_start,
382 const u32 *hash_key = (const u32 *)((const u8 *)key + key_start);
383 int hash_u32s = (key_end - key_start) >> 2;
385 /* Make sure number of hash bytes are multiple of u32. */
386 BUILD_BUG_ON(sizeof(long) % sizeof(u32));
388 return arch_fast_hash2(hash_key, hash_u32s, 0);
391 static int flow_key_start(const struct sw_flow_key *key)
393 if (key->tun_key.ipv4_dst)
396 return rounddown(offsetof(struct sw_flow_key, phy),
400 static bool cmp_key(const struct sw_flow_key *key1,
401 const struct sw_flow_key *key2,
402 int key_start, int key_end)
404 const long *cp1 = (const long *)((const u8 *)key1 + key_start);
405 const long *cp2 = (const long *)((const u8 *)key2 + key_start);
409 for (i = key_start; i < key_end; i += sizeof(long))
410 diffs |= *cp1++ ^ *cp2++;
415 static bool flow_cmp_masked_key(const struct sw_flow *flow,
416 const struct sw_flow_key *key,
417 int key_start, int key_end)
419 return cmp_key(&flow->key, key, key_start, key_end);
422 bool ovs_flow_cmp_unmasked_key(const struct sw_flow *flow,
423 struct sw_flow_match *match)
425 struct sw_flow_key *key = match->key;
426 int key_start = flow_key_start(key);
427 int key_end = match->range.end;
429 return cmp_key(&flow->unmasked_key, key, key_start, key_end);
432 static struct sw_flow *masked_flow_lookup(struct table_instance *ti,
433 const struct sw_flow_key *unmasked,
434 struct sw_flow_mask *mask,
437 struct sw_flow *flow;
438 struct hlist_head *head;
439 int key_start = mask->range.start;
440 int key_end = mask->range.end;
442 struct sw_flow_key masked_key;
444 ovs_flow_mask_key(&masked_key, unmasked, mask);
445 hash = flow_hash(&masked_key, key_start, key_end);
446 head = find_bucket(ti, hash);
448 hlist_for_each_entry_rcu(flow, head, hash_node[ti->node_ver]) {
449 if (flow->mask == mask && flow->hash == hash &&
450 flow_cmp_masked_key(flow, &masked_key,
458 static struct sw_flow *flow_lookup(struct flow_table *tbl,
459 struct table_instance *ti,
460 const struct sw_flow_key *key,
463 struct sw_flow_mask *mask;
464 struct sw_flow *flow;
466 list_for_each_entry_rcu(mask, &tbl->mask_list, list) {
467 flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
468 if (flow) /* Found */
475 * mask_cache maps flow to probable mask. This cache is not tightly
476 * coupled cache, It means updates to mask list can result in inconsistent
477 * cache entry in mask cache.
478 * This is per cpu cache and is divided in MC_HASH_SEGS segments.
479 * In case of a hash collision the entry is hashed in next segment.
481 struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
482 const struct sw_flow_key *key,
486 struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
487 struct mask_cache_entry *entries, *ce, *del;
488 struct sw_flow *flow;
493 if (unlikely(!skb_hash))
494 return flow_lookup(tbl, ti, key, n_mask_hit);
497 entries = this_cpu_ptr(tbl->mask_cache);
499 for (seg = 0; seg < MC_HASH_SEGS; seg++) {
502 index = hash & (MC_HASH_ENTRIES - 1);
503 ce = &entries[index];
505 if (ce->skb_hash == skb_hash) {
506 struct sw_flow_mask *mask;
510 list_for_each_entry_rcu(mask, &tbl->mask_list, list) {
511 if (ce->mask_index == i++) {
512 flow = masked_flow_lookup(ti, key, mask,
514 if (flow) /* Found */
524 if (!del || (del->skb_hash && !ce->skb_hash)) {
528 hash >>= MC_HASH_SHIFT;
531 flow = flow_lookup(tbl, ti, key, n_mask_hit);
534 del->skb_hash = skb_hash;
535 del->mask_index = (*n_mask_hit - 1);
540 struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl,
541 const struct sw_flow_key *key)
543 struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
544 u32 __always_unused n_mask_hit;
547 return flow_lookup(tbl, ti, key, &n_mask_hit);
550 int ovs_flow_tbl_num_masks(const struct flow_table *table)
552 struct sw_flow_mask *mask;
555 list_for_each_entry(mask, &table->mask_list, list)
561 static struct table_instance *table_instance_expand(struct table_instance *ti)
563 return table_instance_rehash(ti, ti->n_buckets * 2);
566 /* Remove 'mask' from the mask list, if it is not needed any more. */
567 static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask)
570 /* ovs-lock is required to protect mask-refcount and
574 BUG_ON(!mask->ref_count);
577 if (!mask->ref_count) {
578 list_del_rcu(&mask->list);
579 call_rcu(&mask->rcu, rcu_free_sw_flow_mask_cb);
584 /* Must be called with OVS mutex held. */
585 void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow)
587 struct table_instance *ti = ovsl_dereference(table->ti);
589 BUG_ON(table->count == 0);
590 hlist_del_rcu(&flow->hash_node[ti->node_ver]);
593 /* RCU delete the mask. 'flow->mask' is not NULLed, as it should be
594 * accessible as long as the RCU read lock is held. */
595 flow_mask_remove(table, flow->mask);
598 static struct sw_flow_mask *mask_alloc(void)
600 struct sw_flow_mask *mask;
602 mask = kmalloc(sizeof(*mask), GFP_KERNEL);
609 static bool mask_equal(const struct sw_flow_mask *a,
610 const struct sw_flow_mask *b)
612 const u8 *a_ = (const u8 *)&a->key + a->range.start;
613 const u8 *b_ = (const u8 *)&b->key + b->range.start;
615 return (a->range.end == b->range.end)
616 && (a->range.start == b->range.start)
617 && (memcmp(a_, b_, range_n_bytes(&a->range)) == 0);
620 static struct sw_flow_mask *flow_mask_find(const struct flow_table *tbl,
621 const struct sw_flow_mask *mask)
623 struct list_head *ml;
625 list_for_each(ml, &tbl->mask_list) {
626 struct sw_flow_mask *m;
627 m = container_of(ml, struct sw_flow_mask, list);
628 if (mask_equal(mask, m))
635 /* Add 'mask' into the mask list, if it is not already there. */
636 static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow,
637 struct sw_flow_mask *new)
639 struct sw_flow_mask *mask;
640 mask = flow_mask_find(tbl, new);
642 /* Allocate a new mask if none exsits. */
646 mask->key = new->key;
647 mask->range = new->range;
648 list_add_tail_rcu(&mask->list, &tbl->mask_list);
650 BUG_ON(!mask->ref_count);
658 /* Must be called with OVS mutex held. */
659 int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow,
660 struct sw_flow_mask *mask)
662 struct table_instance *new_ti = NULL;
663 struct table_instance *ti;
666 err = flow_mask_insert(table, flow, mask);
670 flow->hash = flow_hash(&flow->key, flow->mask->range.start,
671 flow->mask->range.end);
672 ti = ovsl_dereference(table->ti);
673 table_instance_insert(ti, flow);
676 /* Expand table, if necessary, to make room. */
677 if (table->count > ti->n_buckets)
678 new_ti = table_instance_expand(ti);
679 else if (time_after(jiffies, table->last_rehash + REHASH_INTERVAL))
680 new_ti = table_instance_rehash(ti, ti->n_buckets);
683 rcu_assign_pointer(table->ti, new_ti);
684 table_instance_destroy(ti, true);
685 table->last_rehash = jiffies;
690 /* Initializes the flow module.
691 * Returns zero if successful or a negative error code. */
692 int ovs_flow_init(void)
694 BUILD_BUG_ON(__alignof__(struct sw_flow_key) % __alignof__(long));
695 BUILD_BUG_ON(sizeof(struct sw_flow_key) % sizeof(long));
697 flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow)
698 + (num_possible_nodes()
699 * sizeof(struct flow_stats *)),
701 if (flow_cache == NULL)
705 = kmem_cache_create("sw_flow_stats", sizeof(struct flow_stats),
706 0, SLAB_HWCACHE_ALIGN, NULL);
707 if (flow_stats_cache == NULL) {
708 kmem_cache_destroy(flow_cache);
716 /* Uninitializes the flow module. */
717 void ovs_flow_exit(void)
719 kmem_cache_destroy(flow_stats_cache);
720 kmem_cache_destroy(flow_cache);