2 * Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include "classifier.h"
19 #include "classifier-private.h"
21 #include <netinet/in.h>
22 #include "byte-order.h"
23 #include "dynamic-string.h"
28 #include "openvswitch/vlog.h"
30 VLOG_DEFINE_THIS_MODULE(classifier);
34 /* A collection of "struct cls_conjunction"s currently embedded into a
36 struct cls_conjunction_set {
37 /* Link back to the cls_match.
39 * cls_conjunction_set is mostly used during classifier lookup, and, in
40 * turn, during classifier lookup the most used member of
41 * cls_conjunction_set is the rule's priority, so we cache it here for fast
43 struct cls_match *match;
44 int priority; /* Cached copy of match->priority. */
46 /* Conjunction information.
48 * 'min_n_clauses' allows some optimization during classifier lookup. */
49 unsigned int n; /* Number of elements in 'conj'. */
50 unsigned int min_n_clauses; /* Smallest 'n' among elements of 'conj'. */
51 struct cls_conjunction conj[];
54 /* Ports trie depends on both ports sharing the same ovs_be32. */
55 #define TP_PORTS_OFS32 (offsetof(struct flow, tp_src) / 4)
56 BUILD_ASSERT_DECL(TP_PORTS_OFS32 == offsetof(struct flow, tp_dst) / 4);
57 BUILD_ASSERT_DECL(TP_PORTS_OFS32 % 2 == 0);
58 #define TP_PORTS_OFS64 (TP_PORTS_OFS32 / 2)
61 cls_conjunction_set_size(size_t n)
63 return (sizeof(struct cls_conjunction_set)
64 + n * sizeof(struct cls_conjunction));
67 static struct cls_conjunction_set *
68 cls_conjunction_set_alloc(struct cls_match *match,
69 const struct cls_conjunction conj[], size_t n)
72 size_t min_n_clauses = conj[0].n_clauses;
73 for (size_t i = 1; i < n; i++) {
74 min_n_clauses = MIN(min_n_clauses, conj[i].n_clauses);
77 struct cls_conjunction_set *set = xmalloc(cls_conjunction_set_size(n));
79 set->priority = match->priority;
81 set->min_n_clauses = min_n_clauses;
82 memcpy(set->conj, conj, n * sizeof *conj);
89 static struct cls_match *
90 cls_match_alloc(const struct cls_rule *rule, cls_version_t version,
91 const struct cls_conjunction conj[], size_t n)
93 int count = count_1bits(rule->match.flow.map);
95 struct cls_match *cls_match
96 = xmalloc(sizeof *cls_match - sizeof cls_match->flow.inline_values
97 + MINIFLOW_VALUES_SIZE(count));
99 ovsrcu_init(&cls_match->next, NULL);
100 *CONST_CAST(const struct cls_rule **, &cls_match->cls_rule) = rule;
101 *CONST_CAST(int *, &cls_match->priority) = rule->priority;
102 *CONST_CAST(cls_version_t *, &cls_match->add_version) = version;
103 atomic_init(&cls_match->remove_version, version); /* Initially
105 miniflow_clone_inline(CONST_CAST(struct miniflow *, &cls_match->flow),
106 &rule->match.flow, count);
107 ovsrcu_set_hidden(&cls_match->conj_set,
108 cls_conjunction_set_alloc(cls_match, conj, n));
113 static struct cls_subtable *find_subtable(const struct classifier *cls,
114 const struct minimask *);
115 static struct cls_subtable *insert_subtable(struct classifier *cls,
116 const struct minimask *);
117 static void destroy_subtable(struct classifier *cls, struct cls_subtable *);
119 static const struct cls_match *find_match_wc(const struct cls_subtable *,
120 cls_version_t version,
123 unsigned int n_tries,
124 struct flow_wildcards *);
125 static struct cls_match *find_equal(const struct cls_subtable *,
126 const struct miniflow *, uint32_t hash);
128 /* Return the next visible (lower-priority) rule in the list. Multiple
129 * identical rules with the same priority may exist transitionally, but when
130 * versioning is used at most one of them is ever visible for lookups on any
131 * given 'version'. */
132 static inline const struct cls_match *
133 next_visible_rule_in_list(const struct cls_match *rule, cls_version_t version)
136 rule = cls_match_next(rule);
137 } while (rule && !cls_match_visible_in_version(rule, version));
142 static unsigned int minimask_get_prefix_len(const struct minimask *,
143 const struct mf_field *);
144 static void trie_init(struct classifier *cls, int trie_idx,
145 const struct mf_field *);
146 static unsigned int trie_lookup(const struct cls_trie *, const struct flow *,
147 union mf_value *plens);
148 static unsigned int trie_lookup_value(const rcu_trie_ptr *,
149 const ovs_be32 value[], ovs_be32 plens[],
150 unsigned int value_bits);
151 static void trie_destroy(rcu_trie_ptr *);
152 static void trie_insert(struct cls_trie *, const struct cls_rule *, int mlen);
153 static void trie_insert_prefix(rcu_trie_ptr *, const ovs_be32 *prefix,
155 static void trie_remove(struct cls_trie *, const struct cls_rule *, int mlen);
156 static void trie_remove_prefix(rcu_trie_ptr *, const ovs_be32 *prefix,
158 static void mask_set_prefix_bits(struct flow_wildcards *, uint8_t be32ofs,
159 unsigned int n_bits);
160 static bool mask_prefix_bits_set(const struct flow_wildcards *,
161 uint8_t be32ofs, unsigned int n_bits);
166 cls_rule_init__(struct cls_rule *rule, unsigned int priority)
168 rculist_init(&rule->node);
169 *CONST_CAST(int *, &rule->priority) = priority;
170 rule->cls_match = NULL;
173 /* Initializes 'rule' to match packets specified by 'match' at the given
174 * 'priority'. 'match' must satisfy the invariant described in the comment at
175 * the definition of struct match.
177 * The caller must eventually destroy 'rule' with cls_rule_destroy().
179 * Clients should not use priority INT_MIN. (OpenFlow uses priorities between
180 * 0 and UINT16_MAX, inclusive.) */
182 cls_rule_init(struct cls_rule *rule, const struct match *match, int priority)
184 cls_rule_init__(rule, priority);
185 minimatch_init(CONST_CAST(struct minimatch *, &rule->match), match);
188 /* Same as cls_rule_init() for initialization from a "struct minimatch". */
190 cls_rule_init_from_minimatch(struct cls_rule *rule,
191 const struct minimatch *match, int priority)
193 cls_rule_init__(rule, priority);
194 minimatch_clone(CONST_CAST(struct minimatch *, &rule->match), match);
197 /* Initializes 'dst' as a copy of 'src'.
199 * The caller must eventually destroy 'dst' with cls_rule_destroy(). */
201 cls_rule_clone(struct cls_rule *dst, const struct cls_rule *src)
203 cls_rule_init__(dst, src->priority);
204 minimatch_clone(CONST_CAST(struct minimatch *, &dst->match), &src->match);
207 /* Initializes 'dst' with the data in 'src', destroying 'src'.
209 * 'src' must be a cls_rule NOT in a classifier.
211 * The caller must eventually destroy 'dst' with cls_rule_destroy(). */
213 cls_rule_move(struct cls_rule *dst, struct cls_rule *src)
215 cls_rule_init__(dst, src->priority);
216 minimatch_move(CONST_CAST(struct minimatch *, &dst->match),
217 CONST_CAST(struct minimatch *, &src->match));
220 /* Frees memory referenced by 'rule'. Doesn't free 'rule' itself (it's
221 * normally embedded into a larger structure).
223 * ('rule' must not currently be in a classifier.) */
225 cls_rule_destroy(struct cls_rule *rule)
226 OVS_NO_THREAD_SAFETY_ANALYSIS
228 ovs_assert(!rule->cls_match); /* Must not be in a classifier. */
230 /* Check that the rule has been properly removed from the classifier. */
231 ovs_assert(rule->node.prev == RCULIST_POISON
232 || rculist_is_empty(&rule->node));
233 rculist_poison__(&rule->node); /* Poisons also the next pointer. */
235 minimatch_destroy(CONST_CAST(struct minimatch *, &rule->match));
239 cls_rule_set_conjunctions(struct cls_rule *cr,
240 const struct cls_conjunction *conj, size_t n)
242 struct cls_match *match = cr->cls_match;
243 struct cls_conjunction_set *old
244 = ovsrcu_get_protected(struct cls_conjunction_set *, &match->conj_set);
245 struct cls_conjunction *old_conj = old ? old->conj : NULL;
246 unsigned int old_n = old ? old->n : 0;
248 if (old_n != n || (n && memcmp(old_conj, conj, n * sizeof *conj))) {
250 ovsrcu_postpone(free, old);
252 ovsrcu_set(&match->conj_set,
253 cls_conjunction_set_alloc(match, conj, n));
258 /* Returns true if 'a' and 'b' match the same packets at the same priority,
259 * false if they differ in some way. */
261 cls_rule_equal(const struct cls_rule *a, const struct cls_rule *b)
263 return a->priority == b->priority && minimatch_equal(&a->match, &b->match);
266 /* Returns a hash value for 'rule', folding in 'basis'. */
268 cls_rule_hash(const struct cls_rule *rule, uint32_t basis)
270 return minimatch_hash(&rule->match, hash_int(rule->priority, basis));
273 /* Appends a string describing 'rule' to 's'. */
275 cls_rule_format(const struct cls_rule *rule, struct ds *s)
277 minimatch_format(&rule->match, s, rule->priority);
280 /* Returns true if 'rule' matches every packet, false otherwise. */
282 cls_rule_is_catchall(const struct cls_rule *rule)
284 return minimask_is_catchall(&rule->match.mask);
287 /* Makes rule invisible after 'version'. Once that version is made invisible
288 * (by changing the version parameter used in lookups), the rule should be
289 * actually removed via ovsrcu_postpone().
291 * 'rule_' must be in a classifier. */
293 cls_rule_make_invisible_in_version(const struct cls_rule *rule,
294 cls_version_t remove_version)
296 ovs_assert(remove_version >= rule->cls_match->add_version);
298 cls_match_set_remove_version(rule->cls_match, remove_version);
301 /* This undoes the change made by cls_rule_make_invisible_in_version().
303 * 'rule' must be in a classifier. */
305 cls_rule_restore_visibility(const struct cls_rule *rule)
307 cls_match_set_remove_version(rule->cls_match, CLS_NOT_REMOVED_VERSION);
310 /* Return true if 'rule' is visible in 'version'.
312 * 'rule' must be in a classifier. */
314 cls_rule_visible_in_version(const struct cls_rule *rule, cls_version_t version)
316 return cls_match_visible_in_version(rule->cls_match, version);
319 /* Initializes 'cls' as a classifier that initially contains no classification
322 classifier_init(struct classifier *cls, const uint8_t *flow_segments)
325 cmap_init(&cls->subtables_map);
326 pvector_init(&cls->subtables);
327 cmap_init(&cls->partitions);
328 cls->n_flow_segments = 0;
330 while (cls->n_flow_segments < CLS_MAX_INDICES
331 && *flow_segments < FLOW_U64S) {
332 cls->flow_segments[cls->n_flow_segments++] = *flow_segments++;
336 for (int i = 0; i < CLS_MAX_TRIES; i++) {
337 trie_init(cls, i, NULL);
342 /* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
343 * caller's responsibility.
344 * May only be called after all the readers have been terminated. */
346 classifier_destroy(struct classifier *cls)
349 struct cls_partition *partition;
350 struct cls_subtable *subtable;
353 for (i = 0; i < cls->n_tries; i++) {
354 trie_destroy(&cls->tries[i].root);
357 CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
358 destroy_subtable(cls, subtable);
360 cmap_destroy(&cls->subtables_map);
362 CMAP_FOR_EACH (partition, cmap_node, &cls->partitions) {
363 ovsrcu_postpone(free, partition);
365 cmap_destroy(&cls->partitions);
367 pvector_destroy(&cls->subtables);
371 /* Set the fields for which prefix lookup should be performed. */
373 classifier_set_prefix_fields(struct classifier *cls,
374 const enum mf_field_id *trie_fields,
375 unsigned int n_fields)
377 const struct mf_field * new_fields[CLS_MAX_TRIES];
378 struct mf_bitmap fields = MF_BITMAP_INITIALIZER;
380 bool changed = false;
382 for (i = 0; i < n_fields && n_tries < CLS_MAX_TRIES; i++) {
383 const struct mf_field *field = mf_from_id(trie_fields[i]);
384 if (field->flow_be32ofs < 0 || field->n_bits % 32) {
385 /* Incompatible field. This is the only place where we
386 * enforce these requirements, but the rest of the trie code
387 * depends on the flow_be32ofs to be non-negative and the
388 * field length to be a multiple of 32 bits. */
392 if (bitmap_is_set(fields.bm, trie_fields[i])) {
393 /* Duplicate field, there is no need to build more than
394 * one index for any one field. */
397 bitmap_set1(fields.bm, trie_fields[i]);
399 new_fields[n_tries] = NULL;
400 if (n_tries >= cls->n_tries || field != cls->tries[n_tries].field) {
401 new_fields[n_tries] = field;
407 if (changed || n_tries < cls->n_tries) {
408 struct cls_subtable *subtable;
410 /* Trie configuration needs to change. Disable trie lookups
411 * for the tries that are changing and wait all the current readers
412 * with the old configuration to be done. */
414 CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
415 for (i = 0; i < cls->n_tries; i++) {
416 if ((i < n_tries && new_fields[i]) || i >= n_tries) {
417 if (subtable->trie_plen[i]) {
418 subtable->trie_plen[i] = 0;
424 /* Synchronize if any readers were using tries. The readers may
425 * temporarily function without the trie lookup based optimizations. */
427 /* ovsrcu_synchronize() functions as a memory barrier, so it does
428 * not matter that subtable->trie_plen is not atomic. */
429 ovsrcu_synchronize();
432 /* Now set up the tries. */
433 for (i = 0; i < n_tries; i++) {
435 trie_init(cls, i, new_fields[i]);
438 /* Destroy the rest, if any. */
439 for (; i < cls->n_tries; i++) {
440 trie_init(cls, i, NULL);
443 cls->n_tries = n_tries;
447 return false; /* No change. */
451 trie_init(struct classifier *cls, int trie_idx, const struct mf_field *field)
453 struct cls_trie *trie = &cls->tries[trie_idx];
454 struct cls_subtable *subtable;
456 if (trie_idx < cls->n_tries) {
457 trie_destroy(&trie->root);
459 ovsrcu_set_hidden(&trie->root, NULL);
463 /* Add existing rules to the new trie. */
464 CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
467 plen = field ? minimask_get_prefix_len(&subtable->mask, field) : 0;
469 struct cls_match *head;
471 CMAP_FOR_EACH (head, cmap_node, &subtable->rules) {
472 trie_insert(trie, head->cls_rule, plen);
475 /* Initialize subtable's prefix length on this field. This will
476 * allow readers to use the trie. */
477 atomic_thread_fence(memory_order_release);
478 subtable->trie_plen[trie_idx] = plen;
482 /* Returns true if 'cls' contains no classification rules, false otherwise.
483 * Checking the cmap requires no locking. */
485 classifier_is_empty(const struct classifier *cls)
487 return cmap_is_empty(&cls->subtables_map);
490 /* Returns the number of rules in 'cls'. */
492 classifier_count(const struct classifier *cls)
494 /* n_rules is an int, so in the presence of concurrent writers this will
495 * return either the old or a new value. */
500 hash_metadata(ovs_be64 metadata)
502 return hash_uint64((OVS_FORCE uint64_t) metadata);
505 static struct cls_partition *
506 find_partition(const struct classifier *cls, ovs_be64 metadata, uint32_t hash)
508 struct cls_partition *partition;
510 CMAP_FOR_EACH_WITH_HASH (partition, cmap_node, hash, &cls->partitions) {
511 if (partition->metadata == metadata) {
519 static struct cls_partition *
520 create_partition(struct classifier *cls, struct cls_subtable *subtable,
523 uint32_t hash = hash_metadata(metadata);
524 struct cls_partition *partition = find_partition(cls, metadata, hash);
526 partition = xmalloc(sizeof *partition);
527 partition->metadata = metadata;
529 tag_tracker_init(&partition->tracker);
530 cmap_insert(&cls->partitions, &partition->cmap_node, hash);
532 tag_tracker_add(&partition->tracker, &partition->tags, subtable->tag);
536 static inline ovs_be32 minimatch_get_ports(const struct minimatch *match)
538 /* Could optimize to use the same map if needed for fast path. */
539 return MINIFLOW_GET_BE32(&match->flow, tp_src)
540 & MINIFLOW_GET_BE32(&match->mask.masks, tp_src);
544 subtable_replace_head_rule(struct classifier *cls OVS_UNUSED,
545 struct cls_subtable *subtable,
546 struct cls_match *head, struct cls_match *new,
547 uint32_t hash, uint32_t ihash[CLS_MAX_INDICES])
549 /* Rule's data is already in the tries. */
551 new->partition = head->partition; /* Steal partition, if any. */
552 head->partition = NULL;
554 for (int i = 0; i < subtable->n_indices; i++) {
555 cmap_replace(&subtable->indices[i], &head->index_nodes[i],
556 &new->index_nodes[i], ihash[i]);
558 cmap_replace(&subtable->rules, &head->cmap_node, &new->cmap_node, hash);
561 /* Inserts 'rule' into 'cls' in 'version'. Until 'rule' is removed from 'cls',
562 * the caller must not modify or free it.
564 * If 'cls' already contains an identical rule (including wildcards, values of
565 * fixed fields, and priority) that is visible in 'version', replaces the old
566 * rule by 'rule' and returns the rule that was replaced. The caller takes
567 * ownership of the returned rule and is thus responsible for destroying it
568 * with cls_rule_destroy(), after RCU grace period has passed (see
569 * ovsrcu_postpone()).
571 * Returns NULL if 'cls' does not contain a rule with an identical key, after
572 * inserting the new rule. In this case, no rules are displaced by the new
573 * rule, even rules that cannot have any effect because the new rule matches a
574 * superset of their flows and has higher priority.
576 const struct cls_rule *
577 classifier_replace(struct classifier *cls, const struct cls_rule *rule,
578 cls_version_t version,
579 const struct cls_conjunction *conjs, size_t n_conjs)
581 struct cls_match *new;
582 struct cls_subtable *subtable;
583 uint32_t ihash[CLS_MAX_INDICES];
584 uint8_t prev_be64ofs = 0;
585 struct cls_match *head;
591 /* 'new' is initially invisible to lookups. */
592 new = cls_match_alloc(rule, version, conjs, n_conjs);
594 CONST_CAST(struct cls_rule *, rule)->cls_match = new;
596 subtable = find_subtable(cls, &rule->match.mask);
598 subtable = insert_subtable(cls, &rule->match.mask);
601 /* Compute hashes in segments. */
603 for (i = 0; i < subtable->n_indices; i++) {
604 ihash[i] = minimatch_hash_range(&rule->match, prev_be64ofs,
605 subtable->index_ofs[i], &basis);
606 prev_be64ofs = subtable->index_ofs[i];
608 hash = minimatch_hash_range(&rule->match, prev_be64ofs, FLOW_U64S, &basis);
610 head = find_equal(subtable, &rule->match.flow, hash);
612 /* Add rule to tries.
614 * Concurrent readers might miss seeing the rule until this update,
615 * which might require being fixed up by revalidation later. */
616 for (i = 0; i < cls->n_tries; i++) {
617 if (subtable->trie_plen[i]) {
618 trie_insert(&cls->tries[i], rule, subtable->trie_plen[i]);
622 /* Add rule to ports trie. */
623 if (subtable->ports_mask_len) {
624 /* We mask the value to be inserted to always have the wildcarded
625 * bits in known (zero) state, so we can include them in comparison
626 * and they will always match (== their original value does not
628 ovs_be32 masked_ports = minimatch_get_ports(&rule->match);
630 trie_insert_prefix(&subtable->ports_trie, &masked_ports,
631 subtable->ports_mask_len);
634 /* Add rule to partitions.
636 * Concurrent readers might miss seeing the rule until this update,
637 * which might require being fixed up by revalidation later. */
638 new->partition = NULL;
639 if (minimask_get_metadata_mask(&rule->match.mask) == OVS_BE64_MAX) {
640 ovs_be64 metadata = miniflow_get_metadata(&rule->match.flow);
642 new->partition = create_partition(cls, subtable, metadata);
645 /* Add new node to segment indices.
647 * Readers may find the rule in the indices before the rule is visible
648 * in the subtables 'rules' map. This may result in us losing the
649 * opportunity to quit lookups earlier, resulting in sub-optimal
650 * wildcarding. This will be fixed later by revalidation (always
651 * scheduled after flow table changes). */
652 for (i = 0; i < subtable->n_indices; i++) {
653 cmap_insert(&subtable->indices[i], &new->index_nodes[i], ihash[i]);
655 n_rules = cmap_insert(&subtable->rules, &new->cmap_node, hash);
656 } else { /* Equal rules exist in the classifier already. */
657 struct cls_match *prev, *iter;
659 /* Scan the list for the insertion point that will keep the list in
660 * order of decreasing priority. Insert after rules marked invisible
661 * in any version of the same priority. */
662 FOR_EACH_RULE_IN_LIST_PROTECTED (iter, prev, head) {
663 if (rule->priority > iter->priority
664 || (rule->priority == iter->priority
665 && !cls_match_is_eventually_invisible(iter))) {
670 /* Replace 'iter' with 'new' or insert 'new' between 'prev' and
673 struct cls_rule *old;
675 if (rule->priority == iter->priority) {
676 cls_match_replace(prev, iter, new);
677 old = CONST_CAST(struct cls_rule *, iter->cls_rule);
679 cls_match_insert(prev, iter, new);
683 /* Replace the existing head in data structures, if rule is the new
686 subtable_replace_head_rule(cls, subtable, head, new, hash,
691 struct cls_conjunction_set *conj_set;
693 conj_set = ovsrcu_get_protected(struct cls_conjunction_set *,
696 ovsrcu_postpone(free, conj_set);
699 ovsrcu_postpone(cls_match_free_cb, iter);
700 old->cls_match = NULL;
702 /* No change in subtable's max priority or max count. */
704 /* Make 'new' visible to lookups in the appropriate version. */
705 cls_match_set_remove_version(new, CLS_NOT_REMOVED_VERSION);
707 /* Make rule visible to iterators (immediately). */
708 rculist_replace(CONST_CAST(struct rculist *, &rule->node),
711 /* Return displaced rule. Caller is responsible for keeping it
712 * around until all threads quiesce. */
716 /* 'new' is new node after 'prev' */
717 cls_match_insert(prev, iter, new);
721 /* Make 'new' visible to lookups in the appropriate version. */
722 cls_match_set_remove_version(new, CLS_NOT_REMOVED_VERSION);
724 /* Make rule visible to iterators (immediately). */
725 rculist_push_back(&subtable->rules_list,
726 CONST_CAST(struct rculist *, &rule->node));
728 /* Rule was added, not replaced. Update 'subtable's 'max_priority' and
729 * 'max_count', if necessary.
731 * The rule was already inserted, but concurrent readers may not see the
732 * rule yet as the subtables vector is not updated yet. This will have to
733 * be fixed by revalidation later. */
735 subtable->max_priority = rule->priority;
736 subtable->max_count = 1;
737 pvector_insert(&cls->subtables, subtable, rule->priority);
738 } else if (rule->priority == subtable->max_priority) {
739 ++subtable->max_count;
740 } else if (rule->priority > subtable->max_priority) {
741 subtable->max_priority = rule->priority;
742 subtable->max_count = 1;
743 pvector_change_priority(&cls->subtables, subtable, rule->priority);
746 /* Nothing was replaced. */
750 pvector_publish(&cls->subtables);
756 /* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller
757 * must not modify or free it.
759 * 'cls' must not contain an identical rule (including wildcards, values of
760 * fixed fields, and priority). Use classifier_find_rule_exactly() to find
763 classifier_insert(struct classifier *cls, const struct cls_rule *rule,
764 cls_version_t version, const struct cls_conjunction conj[],
767 const struct cls_rule *displaced_rule
768 = classifier_replace(cls, rule, version, conj, n_conj);
769 ovs_assert(!displaced_rule);
772 /* Removes 'rule' from 'cls'. It is the caller's responsibility to destroy
773 * 'rule' with cls_rule_destroy(), freeing the memory block in which 'rule'
774 * resides, etc., as necessary.
776 * Does nothing if 'rule' has been already removed, or was never inserted.
778 * Returns the removed rule, or NULL, if it was already removed.
780 const struct cls_rule *
781 classifier_remove(struct classifier *cls, const struct cls_rule *cls_rule)
783 struct cls_match *rule, *prev, *next, *head;
784 struct cls_partition *partition;
785 struct cls_conjunction_set *conj_set;
786 struct cls_subtable *subtable;
788 uint32_t basis = 0, hash, ihash[CLS_MAX_INDICES];
789 uint8_t prev_be64ofs = 0;
792 rule = cls_rule->cls_match;
796 /* Mark as removed. */
797 CONST_CAST(struct cls_rule *, cls_rule)->cls_match = NULL;
799 /* Remove 'cls_rule' from the subtable's rules list. */
800 rculist_remove(CONST_CAST(struct rculist *, &cls_rule->node));
802 subtable = find_subtable(cls, &cls_rule->match.mask);
803 ovs_assert(subtable);
805 for (i = 0; i < subtable->n_indices; i++) {
806 ihash[i] = minimatch_hash_range(&cls_rule->match, prev_be64ofs,
807 subtable->index_ofs[i], &basis);
808 prev_be64ofs = subtable->index_ofs[i];
810 hash = minimatch_hash_range(&cls_rule->match, prev_be64ofs, FLOW_U64S,
813 head = find_equal(subtable, &cls_rule->match.flow, hash);
815 /* Check if the rule is not the head rule. */
817 struct cls_match *iter;
819 /* Not the head rule, but potentially one with the same priority. */
820 /* Remove from the list of equal rules. */
821 FOR_EACH_RULE_IN_LIST_PROTECTED (iter, prev, head) {
826 ovs_assert(iter == rule);
828 cls_match_remove(prev, rule);
833 /* 'rule' is the head rule. Check if there is another rule to
834 * replace 'rule' in the data structures. */
835 next = cls_match_next_protected(rule);
837 subtable_replace_head_rule(cls, subtable, rule, next, hash, ihash);
841 /* 'rule' is last of the kind in the classifier, must remove from all the
842 * data structures. */
844 if (subtable->ports_mask_len) {
845 ovs_be32 masked_ports = minimatch_get_ports(&cls_rule->match);
847 trie_remove_prefix(&subtable->ports_trie,
848 &masked_ports, subtable->ports_mask_len);
850 for (i = 0; i < cls->n_tries; i++) {
851 if (subtable->trie_plen[i]) {
852 trie_remove(&cls->tries[i], cls_rule, subtable->trie_plen[i]);
856 /* Remove rule node from indices. */
857 for (i = 0; i < subtable->n_indices; i++) {
858 cmap_remove(&subtable->indices[i], &rule->index_nodes[i], ihash[i]);
860 n_rules = cmap_remove(&subtable->rules, &rule->cmap_node, hash);
862 partition = rule->partition;
864 tag_tracker_subtract(&partition->tracker, &partition->tags,
866 if (!partition->tags) {
867 cmap_remove(&cls->partitions, &partition->cmap_node,
868 hash_metadata(partition->metadata));
869 ovsrcu_postpone(free, partition);
874 destroy_subtable(cls, subtable);
877 if (subtable->max_priority == rule->priority
878 && --subtable->max_count == 0) {
879 /* Find the new 'max_priority' and 'max_count'. */
880 int max_priority = INT_MIN;
881 struct cls_match *head;
883 CMAP_FOR_EACH (head, cmap_node, &subtable->rules) {
884 if (head->priority > max_priority) {
885 max_priority = head->priority;
886 subtable->max_count = 1;
887 } else if (head->priority == max_priority) {
888 ++subtable->max_count;
891 subtable->max_priority = max_priority;
892 pvector_change_priority(&cls->subtables, subtable, max_priority);
897 pvector_publish(&cls->subtables);
901 conj_set = ovsrcu_get_protected(struct cls_conjunction_set *,
904 ovsrcu_postpone(free, conj_set);
906 ovsrcu_postpone(cls_match_free_cb, rule);
912 /* Prefix tree context. Valid when 'lookup_done' is true. Can skip all
913 * subtables which have a prefix match on the trie field, but whose prefix
914 * length is not indicated in 'match_plens'. For example, a subtable that
915 * has a 8-bit trie field prefix match can be skipped if
916 * !be_get_bit_at(&match_plens, 8 - 1). If skipped, 'maskbits' prefix bits
917 * must be unwildcarded to make datapath flow only match packets it should. */
919 const struct cls_trie *trie;
920 bool lookup_done; /* Status of the lookup. */
921 uint8_t be32ofs; /* U32 offset of the field in question. */
922 unsigned int maskbits; /* Prefix length needed to avoid false matches. */
923 union mf_value match_plens; /* Bitmask of prefix lengths with possible
928 trie_ctx_init(struct trie_ctx *ctx, const struct cls_trie *trie)
931 ctx->be32ofs = trie->field->flow_be32ofs;
932 ctx->lookup_done = false;
935 struct conjunctive_match {
936 struct hmap_node hmap_node;
941 static struct conjunctive_match *
942 find_conjunctive_match__(struct hmap *matches, uint64_t id, uint32_t hash)
944 struct conjunctive_match *m;
946 HMAP_FOR_EACH_IN_BUCKET (m, hmap_node, hash, matches) {
955 find_conjunctive_match(const struct cls_conjunction_set *set,
956 unsigned int max_n_clauses, struct hmap *matches,
957 struct conjunctive_match *cm_stubs, size_t n_cm_stubs,
960 const struct cls_conjunction *c;
962 if (max_n_clauses < set->min_n_clauses) {
966 for (c = set->conj; c < &set->conj[set->n]; c++) {
967 struct conjunctive_match *cm;
970 if (c->n_clauses > max_n_clauses) {
974 hash = hash_int(c->id, 0);
975 cm = find_conjunctive_match__(matches, c->id, hash);
977 size_t n = hmap_count(matches);
979 cm = n < n_cm_stubs ? &cm_stubs[n] : xmalloc(sizeof *cm);
980 hmap_insert(matches, &cm->hmap_node, hash);
982 cm->clauses = UINT64_MAX << (c->n_clauses & 63);
984 cm->clauses |= UINT64_C(1) << c->clause;
985 if (cm->clauses == UINT64_MAX) {
994 free_conjunctive_matches(struct hmap *matches,
995 struct conjunctive_match *cm_stubs, size_t n_cm_stubs)
997 if (hmap_count(matches) > n_cm_stubs) {
998 struct conjunctive_match *cm, *next;
1000 HMAP_FOR_EACH_SAFE (cm, next, hmap_node, matches) {
1001 if (!(cm >= cm_stubs && cm < &cm_stubs[n_cm_stubs])) {
1006 hmap_destroy(matches);
1009 /* Like classifier_lookup(), except that support for conjunctive matches can be
1010 * configured with 'allow_conjunctive_matches'. That feature is not exposed
1011 * externally because turning off conjunctive matches is only useful to avoid
1012 * recursion within this function itself.
1014 * 'flow' is non-const to allow for temporary modifications during the lookup.
1015 * Any changes are restored before returning. */
1016 static const struct cls_rule *
1017 classifier_lookup__(const struct classifier *cls, cls_version_t version,
1018 struct flow *flow, struct flow_wildcards *wc,
1019 bool allow_conjunctive_matches)
1021 const struct cls_partition *partition;
1022 struct trie_ctx trie_ctx[CLS_MAX_TRIES];
1023 const struct cls_match *match;
1026 /* Highest-priority flow in 'cls' that certainly matches 'flow'. */
1027 const struct cls_match *hard = NULL;
1028 int hard_pri = INT_MIN; /* hard ? hard->priority : INT_MIN. */
1030 /* Highest-priority conjunctive flows in 'cls' matching 'flow'. Since
1031 * these are (components of) conjunctive flows, we can only know whether
1032 * the full conjunctive flow matches after seeing multiple of them. Thus,
1033 * we refer to these as "soft matches". */
1034 struct cls_conjunction_set *soft_stub[64];
1035 struct cls_conjunction_set **soft = soft_stub;
1036 size_t n_soft = 0, allocated_soft = ARRAY_SIZE(soft_stub);
1037 int soft_pri = INT_MIN; /* n_soft ? MAX(soft[*]->priority) : INT_MIN. */
1039 /* Synchronize for cls->n_tries and subtable->trie_plen. They can change
1040 * when table configuration changes, which happens typically only on
1042 atomic_thread_fence(memory_order_acquire);
1044 /* Determine 'tags' such that, if 'subtable->tag' doesn't intersect them,
1045 * then 'flow' cannot possibly match in 'subtable':
1047 * - If flow->metadata maps to a given 'partition', then we can use
1048 * 'tags' for 'partition->tags'.
1050 * - If flow->metadata has no partition, then no rule in 'cls' has an
1051 * exact-match for flow->metadata. That means that we don't need to
1052 * search any subtable that includes flow->metadata in its mask.
1054 * In either case, we always need to search any cls_subtables that do not
1055 * include flow->metadata in its mask. One way to do that would be to
1056 * check the "cls_subtable"s explicitly for that, but that would require an
1057 * extra branch per subtable. Instead, we mark such a cls_subtable's
1058 * 'tags' as TAG_ALL and make sure that 'tags' is never empty. This means
1059 * that 'tags' always intersects such a cls_subtable's 'tags', so we don't
1060 * need a special case.
1062 partition = (cmap_is_empty(&cls->partitions)
1064 : find_partition(cls, flow->metadata,
1065 hash_metadata(flow->metadata)));
1066 tags = partition ? partition->tags : TAG_ARBITRARY;
1068 /* Initialize trie contexts for find_match_wc(). */
1069 for (int i = 0; i < cls->n_tries; i++) {
1070 trie_ctx_init(&trie_ctx[i], &cls->tries[i]);
1074 struct cls_subtable *subtable;
1075 PVECTOR_FOR_EACH_PRIORITY (subtable, hard_pri, 2, sizeof *subtable,
1077 struct cls_conjunction_set *conj_set;
1079 /* Skip subtables not in our partition. */
1080 if (!tag_intersects(tags, subtable->tag)) {
1084 /* Skip subtables with no match, or where the match is lower-priority
1085 * than some certain match we've already found. */
1086 match = find_match_wc(subtable, version, flow, trie_ctx, cls->n_tries,
1088 if (!match || match->priority <= hard_pri) {
1092 conj_set = ovsrcu_get(struct cls_conjunction_set *, &match->conj_set);
1094 /* 'match' isn't part of a conjunctive match. It's the best
1095 * certain match we've got so far, since we know that it's
1096 * higher-priority than hard_pri.
1098 * (There might be a higher-priority conjunctive match. We can't
1101 hard_pri = hard->priority;
1102 } else if (allow_conjunctive_matches) {
1103 /* 'match' is part of a conjunctive match. Add it to the list. */
1104 if (OVS_UNLIKELY(n_soft >= allocated_soft)) {
1105 struct cls_conjunction_set **old_soft = soft;
1107 allocated_soft *= 2;
1108 soft = xmalloc(allocated_soft * sizeof *soft);
1109 memcpy(soft, old_soft, n_soft * sizeof *soft);
1110 if (old_soft != soft_stub) {
1114 soft[n_soft++] = conj_set;
1116 /* Keep track of the highest-priority soft match. */
1117 if (soft_pri < match->priority) {
1118 soft_pri = match->priority;
1123 /* In the common case, at this point we have no soft matches and we can
1124 * return immediately. (We do the same thing if we have potential soft
1125 * matches but none of them are higher-priority than our hard match.) */
1126 if (hard_pri >= soft_pri) {
1127 if (soft != soft_stub) {
1130 return hard ? hard->cls_rule : NULL;
1133 /* At this point, we have some soft matches. We might also have a hard
1134 * match; if so, its priority is lower than the highest-priority soft
1139 * Check whether soft matches are real matches. */
1141 /* Delete soft matches that are null. This only happens in second and
1142 * subsequent iterations of the soft match loop, when we drop back from
1143 * a high-priority soft match to a lower-priority one.
1145 * Also, delete soft matches whose priority is less than or equal to
1146 * the hard match's priority. In the first iteration of the soft
1147 * match, these can be in 'soft' because the earlier main loop found
1148 * the soft match before the hard match. In second and later iteration
1149 * of the soft match loop, these can be in 'soft' because we dropped
1150 * back from a high-priority soft match to a lower-priority soft match.
1152 * It is tempting to delete soft matches that cannot be satisfied
1153 * because there are fewer soft matches than required to satisfy any of
1154 * their conjunctions, but we cannot do that because there might be
1155 * lower priority soft or hard matches with otherwise identical
1156 * matches. (We could special case those here, but there's no
1157 * need--we'll do so at the bottom of the soft match loop anyway and
1158 * this duplicates less code.)
1160 * It's also tempting to break out of the soft match loop if 'n_soft ==
1161 * 1' but that would also miss lower-priority hard matches. We could
1162 * special case that also but again there's no need. */
1163 for (int i = 0; i < n_soft; ) {
1164 if (!soft[i] || soft[i]->priority <= hard_pri) {
1165 soft[i] = soft[--n_soft];
1174 /* Find the highest priority among the soft matches. (We know this
1175 * must be higher than the hard match's priority; otherwise we would
1176 * have deleted all of the soft matches in the previous loop.) Count
1177 * the number of soft matches that have that priority. */
1180 for (int i = 0; i < n_soft; i++) {
1181 if (soft[i]->priority > soft_pri) {
1182 soft_pri = soft[i]->priority;
1184 } else if (soft[i]->priority == soft_pri) {
1188 ovs_assert(soft_pri > hard_pri);
1190 /* Look for a real match among the highest-priority soft matches.
1192 * It's unusual to have many conjunctive matches, so we use stubs to
1193 * avoid calling malloc() in the common case. An hmap has a built-in
1194 * stub for up to 2 hmap_nodes; possibly, we would benefit a variant
1195 * with a bigger stub. */
1196 struct conjunctive_match cm_stubs[16];
1197 struct hmap matches;
1199 hmap_init(&matches);
1200 for (int i = 0; i < n_soft; i++) {
1203 if (soft[i]->priority == soft_pri
1204 && find_conjunctive_match(soft[i], n_soft_pri, &matches,
1205 cm_stubs, ARRAY_SIZE(cm_stubs),
1207 uint32_t saved_conj_id = flow->conj_id;
1208 const struct cls_rule *rule;
1211 rule = classifier_lookup__(cls, version, flow, wc, false);
1212 flow->conj_id = saved_conj_id;
1215 free_conjunctive_matches(&matches,
1216 cm_stubs, ARRAY_SIZE(cm_stubs));
1217 if (soft != soft_stub) {
1224 free_conjunctive_matches(&matches, cm_stubs, ARRAY_SIZE(cm_stubs));
1226 /* There's no real match among the highest-priority soft matches.
1227 * However, if any of those soft matches has a lower-priority but
1228 * otherwise identical flow match, then we need to consider those for
1229 * soft or hard matches.
1231 * The next iteration of the soft match loop will delete any null
1232 * pointers we put into 'soft' (and some others too). */
1233 for (int i = 0; i < n_soft; i++) {
1234 if (soft[i]->priority != soft_pri) {
1238 /* Find next-lower-priority flow with identical flow match. */
1239 match = next_visible_rule_in_list(soft[i]->match, version);
1241 soft[i] = ovsrcu_get(struct cls_conjunction_set *,
1244 /* The flow is a hard match; don't treat as a soft
1246 if (match->priority > hard_pri) {
1248 hard_pri = hard->priority;
1252 /* No such lower-priority flow (probably the common case). */
1258 if (soft != soft_stub) {
1261 return hard ? hard->cls_rule : NULL;
1264 /* Finds and returns the highest-priority rule in 'cls' that matches 'flow' and
1265 * that is visible in 'version'. Returns a null pointer if no rules in 'cls'
1266 * match 'flow'. If multiple rules of equal priority match 'flow', returns one
1269 * If a rule is found and 'wc' is non-null, bitwise-OR's 'wc' with the
1270 * set of bits that were significant in the lookup. At some point
1271 * earlier, 'wc' should have been initialized (e.g., by
1272 * flow_wildcards_init_catchall()).
1274 * 'flow' is non-const to allow for temporary modifications during the lookup.
1275 * Any changes are restored before returning. */
1276 const struct cls_rule *
1277 classifier_lookup(const struct classifier *cls, cls_version_t version,
1278 struct flow *flow, struct flow_wildcards *wc)
1280 return classifier_lookup__(cls, version, flow, wc, true);
1283 /* Finds and returns a rule in 'cls' with exactly the same priority and
1284 * matching criteria as 'target', and that is visible in 'version'.
1285 * Only one such rule may ever exist. Returns a null pointer if 'cls' doesn't
1286 * contain an exact match. */
1287 const struct cls_rule *
1288 classifier_find_rule_exactly(const struct classifier *cls,
1289 const struct cls_rule *target,
1290 cls_version_t version)
1292 const struct cls_match *head, *rule;
1293 const struct cls_subtable *subtable;
1295 subtable = find_subtable(cls, &target->match.mask);
1300 head = find_equal(subtable, &target->match.flow,
1301 miniflow_hash_in_minimask(&target->match.flow,
1302 &target->match.mask, 0));
1306 CLS_MATCH_FOR_EACH (rule, head) {
1307 if (rule->priority < target->priority) {
1308 break; /* Not found. */
1310 if (rule->priority == target->priority
1311 && cls_match_visible_in_version(rule, version)) {
1312 return rule->cls_rule;
1318 /* Finds and returns a rule in 'cls' with priority 'priority' and exactly the
1319 * same matching criteria as 'target', and that is visible in 'version'.
1320 * Returns a null pointer if 'cls' doesn't contain an exact match visible in
1322 const struct cls_rule *
1323 classifier_find_match_exactly(const struct classifier *cls,
1324 const struct match *target, int priority,
1325 cls_version_t version)
1327 const struct cls_rule *retval;
1330 cls_rule_init(&cr, target, priority);
1331 retval = classifier_find_rule_exactly(cls, &cr, version);
1332 cls_rule_destroy(&cr);
1337 /* Checks if 'target' would overlap any other rule in 'cls' in 'version'. Two
1338 * rules are considered to overlap if both rules have the same priority and a
1339 * packet could match both, and if both rules are visible in the same version.
1341 * A trivial example of overlapping rules is two rules matching disjoint sets
1342 * of fields. E.g., if one rule matches only on port number, while another only
1343 * on dl_type, any packet from that specific port and with that specific
1344 * dl_type could match both, if the rules also have the same priority. */
1346 classifier_rule_overlaps(const struct classifier *cls,
1347 const struct cls_rule *target, cls_version_t version)
1349 struct cls_subtable *subtable;
1351 /* Iterate subtables in the descending max priority order. */
1352 PVECTOR_FOR_EACH_PRIORITY (subtable, target->priority - 1, 2,
1353 sizeof(struct cls_subtable), &cls->subtables) {
1354 uint64_t storage[FLOW_U64S];
1355 struct minimask mask;
1356 const struct cls_rule *rule;
1358 minimask_combine(&mask, &target->match.mask, &subtable->mask, storage);
1360 RCULIST_FOR_EACH (rule, node, &subtable->rules_list) {
1361 if (rule->priority == target->priority
1362 && miniflow_equal_in_minimask(&target->match.flow,
1363 &rule->match.flow, &mask)
1364 && cls_match_visible_in_version(rule->cls_match, version)) {
1372 /* Returns true if 'rule' exactly matches 'criteria' or if 'rule' is more
1373 * specific than 'criteria'. That is, 'rule' matches 'criteria' and this
1374 * function returns true if, for every field:
1376 * - 'criteria' and 'rule' specify the same (non-wildcarded) value for the
1379 * - 'criteria' wildcards the field,
1381 * Conversely, 'rule' does not match 'criteria' and this function returns false
1382 * if, for at least one field:
1384 * - 'criteria' and 'rule' specify different values for the field, or
1386 * - 'criteria' specifies a value for the field but 'rule' wildcards it.
1388 * Equivalently, the truth table for whether a field matches is:
1393 * r +---------+---------+
1394 * i wild | yes | yes |
1396 * e +---------+---------+
1397 * r exact | no |if values|
1399 * a +---------+---------+
1401 * This is the matching rule used by OpenFlow 1.0 non-strict OFPT_FLOW_MOD
1402 * commands and by OpenFlow 1.0 aggregate and flow stats.
1404 * Ignores rule->priority. */
1406 cls_rule_is_loose_match(const struct cls_rule *rule,
1407 const struct minimatch *criteria)
1409 return (!minimask_has_extra(&rule->match.mask, &criteria->mask)
1410 && miniflow_equal_in_minimask(&rule->match.flow, &criteria->flow,
1417 rule_matches(const struct cls_rule *rule, const struct cls_rule *target,
1418 cls_version_t version)
1420 /* Rule may only match a target if it is visible in target's version. */
1421 return cls_match_visible_in_version(rule->cls_match, version)
1422 && (!target || miniflow_equal_in_minimask(&rule->match.flow,
1423 &target->match.flow,
1424 &target->match.mask));
1427 static const struct cls_rule *
1428 search_subtable(const struct cls_subtable *subtable,
1429 struct cls_cursor *cursor)
1432 || !minimask_has_extra(&subtable->mask, &cursor->target->match.mask)) {
1433 const struct cls_rule *rule;
1435 RCULIST_FOR_EACH (rule, node, &subtable->rules_list) {
1436 if (rule_matches(rule, cursor->target, cursor->version)) {
1444 /* Initializes 'cursor' for iterating through rules in 'cls', and returns the
1447 * - If 'target' is null, or if the 'target' is a catchall target, the
1448 * cursor will visit every rule in 'cls' that is visible in 'version'.
1450 * - If 'target' is nonnull, the cursor will visit each 'rule' in 'cls'
1451 * such that cls_rule_is_loose_match(rule, target) returns true and that
1452 * the rule is visible in 'version'.
1454 * Ignores target->priority. */
1456 cls_cursor_start(const struct classifier *cls, const struct cls_rule *target,
1457 cls_version_t version)
1459 struct cls_cursor cursor;
1460 struct cls_subtable *subtable;
1463 cursor.target = target && !cls_rule_is_catchall(target) ? target : NULL;
1464 cursor.version = version;
1467 /* Find first rule. */
1468 PVECTOR_CURSOR_FOR_EACH (subtable, &cursor.subtables,
1469 &cursor.cls->subtables) {
1470 const struct cls_rule *rule = search_subtable(subtable, &cursor);
1473 cursor.subtable = subtable;
1482 static const struct cls_rule *
1483 cls_cursor_next(struct cls_cursor *cursor)
1485 const struct cls_rule *rule;
1486 const struct cls_subtable *subtable;
1488 rule = cursor->rule;
1489 subtable = cursor->subtable;
1490 RCULIST_FOR_EACH_CONTINUE (rule, node, &subtable->rules_list) {
1491 if (rule_matches(rule, cursor->target, cursor->version)) {
1496 PVECTOR_CURSOR_FOR_EACH_CONTINUE (subtable, &cursor->subtables) {
1497 rule = search_subtable(subtable, cursor);
1499 cursor->subtable = subtable;
1507 /* Sets 'cursor->rule' to the next matching cls_rule in 'cursor''s iteration,
1508 * or to null if all matching rules have been visited. */
1510 cls_cursor_advance(struct cls_cursor *cursor)
1512 cursor->rule = cls_cursor_next(cursor);
1515 static struct cls_subtable *
1516 find_subtable(const struct classifier *cls, const struct minimask *mask)
1518 struct cls_subtable *subtable;
1520 CMAP_FOR_EACH_WITH_HASH (subtable, cmap_node, minimask_hash(mask, 0),
1521 &cls->subtables_map) {
1522 if (minimask_equal(mask, &subtable->mask)) {
1529 /* The new subtable will be visible to the readers only after this. */
1530 static struct cls_subtable *
1531 insert_subtable(struct classifier *cls, const struct minimask *mask)
1533 uint32_t hash = minimask_hash(mask, 0);
1534 struct cls_subtable *subtable;
1536 struct flow_wildcards old, new;
1538 int count = count_1bits(mask->masks.map);
1540 subtable = xzalloc(sizeof *subtable - sizeof mask->masks.inline_values
1541 + MINIFLOW_VALUES_SIZE(count));
1542 cmap_init(&subtable->rules);
1543 miniflow_clone_inline(CONST_CAST(struct miniflow *, &subtable->mask.masks),
1544 &mask->masks, count);
1546 /* Init indices for segmented lookup, if any. */
1547 flow_wildcards_init_catchall(&new);
1550 for (i = 0; i < cls->n_flow_segments; i++) {
1551 flow_wildcards_fold_minimask_range(&new, mask, prev,
1552 cls->flow_segments[i]);
1553 /* Add an index if it adds mask bits. */
1554 if (!flow_wildcards_equal(&new, &old)) {
1555 cmap_init(&subtable->indices[index]);
1556 *CONST_CAST(uint8_t *, &subtable->index_ofs[index])
1557 = cls->flow_segments[i];
1561 prev = cls->flow_segments[i];
1563 /* Check if the rest of the subtable's mask adds any bits,
1564 * and remove the last index if it doesn't. */
1566 flow_wildcards_fold_minimask_range(&new, mask, prev, FLOW_U64S);
1567 if (flow_wildcards_equal(&new, &old)) {
1569 *CONST_CAST(uint8_t *, &subtable->index_ofs[index]) = 0;
1570 cmap_destroy(&subtable->indices[index]);
1573 *CONST_CAST(uint8_t *, &subtable->n_indices) = index;
1575 *CONST_CAST(tag_type *, &subtable->tag) =
1576 (minimask_get_metadata_mask(mask) == OVS_BE64_MAX
1577 ? tag_create_deterministic(hash)
1580 for (i = 0; i < cls->n_tries; i++) {
1581 subtable->trie_plen[i] = minimask_get_prefix_len(mask,
1582 cls->tries[i].field);
1586 ovsrcu_set_hidden(&subtable->ports_trie, NULL);
1587 *CONST_CAST(int *, &subtable->ports_mask_len)
1588 = 32 - ctz32(ntohl(MINIFLOW_GET_BE32(&mask->masks, tp_src)));
1590 /* List of rules. */
1591 rculist_init(&subtable->rules_list);
1593 cmap_insert(&cls->subtables_map, &subtable->cmap_node, hash);
1598 /* RCU readers may still access the subtable before it is actually freed. */
1600 destroy_subtable(struct classifier *cls, struct cls_subtable *subtable)
1604 pvector_remove(&cls->subtables, subtable);
1605 cmap_remove(&cls->subtables_map, &subtable->cmap_node,
1606 minimask_hash(&subtable->mask, 0));
1608 ovs_assert(ovsrcu_get_protected(struct trie_node *, &subtable->ports_trie)
1610 ovs_assert(cmap_is_empty(&subtable->rules));
1611 ovs_assert(rculist_is_empty(&subtable->rules_list));
1613 for (i = 0; i < subtable->n_indices; i++) {
1614 cmap_destroy(&subtable->indices[i]);
1616 cmap_destroy(&subtable->rules);
1617 ovsrcu_postpone(free, subtable);
1625 static unsigned int be_get_bit_at(const ovs_be32 value[], unsigned int ofs);
1627 /* Return 'true' if can skip rest of the subtable based on the prefix trie
1628 * lookup results. */
1630 check_tries(struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries,
1631 const unsigned int field_plen[CLS_MAX_TRIES],
1632 const struct range ofs, const struct flow *flow,
1633 struct flow_wildcards *wc)
1637 /* Check if we could avoid fully unwildcarding the next level of
1638 * fields using the prefix tries. The trie checks are done only as
1639 * needed to avoid folding in additional bits to the wildcards mask. */
1640 for (j = 0; j < n_tries; j++) {
1641 /* Is the trie field relevant for this subtable? */
1642 if (field_plen[j]) {
1643 struct trie_ctx *ctx = &trie_ctx[j];
1644 uint8_t be32ofs = ctx->be32ofs;
1645 uint8_t be64ofs = be32ofs / 2;
1647 /* Is the trie field within the current range of fields? */
1648 if (be64ofs >= ofs.start && be64ofs < ofs.end) {
1649 /* On-demand trie lookup. */
1650 if (!ctx->lookup_done) {
1651 memset(&ctx->match_plens, 0, sizeof ctx->match_plens);
1652 ctx->maskbits = trie_lookup(ctx->trie, flow,
1654 ctx->lookup_done = true;
1656 /* Possible to skip the rest of the subtable if subtable's
1657 * prefix on the field is not included in the lookup result. */
1658 if (!be_get_bit_at(&ctx->match_plens.be32, field_plen[j] - 1)) {
1659 /* We want the trie lookup to never result in unwildcarding
1660 * any bits that would not be unwildcarded otherwise.
1661 * Since the trie is shared by the whole classifier, it is
1662 * possible that the 'maskbits' contain bits that are
1663 * irrelevant for the partition relevant for the current
1664 * packet. Hence the checks below. */
1666 /* Check that the trie result will not unwildcard more bits
1667 * than this subtable would otherwise. */
1668 if (ctx->maskbits <= field_plen[j]) {
1669 /* Unwildcard the bits and skip the rest. */
1670 mask_set_prefix_bits(wc, be32ofs, ctx->maskbits);
1671 /* Note: Prerequisite already unwildcarded, as the only
1672 * prerequisite of the supported trie lookup fields is
1673 * the ethertype, which is always unwildcarded. */
1676 /* Can skip if the field is already unwildcarded. */
1677 if (mask_prefix_bits_set(wc, be32ofs, ctx->maskbits)) {
1687 /* Returns true if 'target' satisifies 'flow'/'mask', that is, if each bit
1688 * for which 'flow', for which 'mask' has a bit set, specifies a particular
1689 * value has the correct value in 'target'.
1691 * This function is equivalent to miniflow_equal_flow_in_minimask(flow,
1692 * target, mask) but this is faster because of the invariant that
1693 * flow->map and mask->masks.map are the same, and that this version
1694 * takes the 'wc'. */
1696 miniflow_and_mask_matches_flow(const struct miniflow *flow,
1697 const struct minimask *mask,
1698 const struct flow *target)
1700 const uint64_t *flowp = miniflow_get_values(flow);
1701 const uint64_t *maskp = miniflow_get_values(&mask->masks);
1704 MAP_FOR_EACH_INDEX(idx, mask->masks.map) {
1705 uint64_t diff = (*flowp++ ^ flow_u64_value(target, idx)) & *maskp++;
1715 static inline const struct cls_match *
1716 find_match(const struct cls_subtable *subtable, cls_version_t version,
1717 const struct flow *flow, uint32_t hash)
1719 const struct cls_match *head, *rule;
1721 CMAP_FOR_EACH_WITH_HASH (head, cmap_node, hash, &subtable->rules) {
1722 if (OVS_LIKELY(miniflow_and_mask_matches_flow(&head->flow,
1725 /* Return highest priority rule that is visible. */
1726 CLS_MATCH_FOR_EACH (rule, head) {
1727 if (OVS_LIKELY(cls_match_visible_in_version(rule, version))) {
1737 /* Returns true if 'target' satisifies 'flow'/'mask', that is, if each bit
1738 * for which 'flow', for which 'mask' has a bit set, specifies a particular
1739 * value has the correct value in 'target'.
1741 * This function is equivalent to miniflow_and_mask_matches_flow() but this
1742 * version fills in the mask bits in 'wc'. */
1744 miniflow_and_mask_matches_flow_wc(const struct miniflow *flow,
1745 const struct minimask *mask,
1746 const struct flow *target,
1747 struct flow_wildcards *wc)
1749 const uint64_t *flowp = miniflow_get_values(flow);
1750 const uint64_t *maskp = miniflow_get_values(&mask->masks);
1753 MAP_FOR_EACH_INDEX(idx, mask->masks.map) {
1754 uint64_t mask = *maskp++;
1755 uint64_t diff = (*flowp++ ^ flow_u64_value(target, idx)) & mask;
1758 /* Only unwildcard if none of the differing bits is already
1760 if (!(flow_u64_value(&wc->masks, idx) & diff)) {
1761 /* Keep one bit of the difference. The selected bit may be
1762 * different in big-endian v.s. little-endian systems. */
1763 *flow_u64_lvalue(&wc->masks, idx) |= rightmost_1bit(diff);
1767 /* Fill in the bits that were looked at. */
1768 *flow_u64_lvalue(&wc->masks, idx) |= mask;
1774 /* Unwildcard the fields looked up so far, if any. */
1776 fill_range_wc(const struct cls_subtable *subtable, struct flow_wildcards *wc,
1780 flow_wildcards_fold_minimask_range(wc, &subtable->mask, 0, to);
1784 static const struct cls_match *
1785 find_match_wc(const struct cls_subtable *subtable, cls_version_t version,
1786 const struct flow *flow, struct trie_ctx trie_ctx[CLS_MAX_TRIES],
1787 unsigned int n_tries, struct flow_wildcards *wc)
1789 uint32_t basis = 0, hash;
1790 const struct cls_match *rule = NULL;
1794 if (OVS_UNLIKELY(!wc)) {
1795 return find_match(subtable, version, flow,
1796 flow_hash_in_minimask(flow, &subtable->mask, 0));
1800 /* Try to finish early by checking fields in segments. */
1801 for (i = 0; i < subtable->n_indices; i++) {
1802 const struct cmap_node *inode;
1804 ofs.end = subtable->index_ofs[i];
1806 if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow,
1808 /* 'wc' bits for the trie field set, now unwildcard the preceding
1809 * bits used so far. */
1810 fill_range_wc(subtable, wc, ofs.start);
1813 hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
1815 inode = cmap_find(&subtable->indices[i], hash);
1817 /* No match, can stop immediately, but must fold in the bits
1818 * used in lookup so far. */
1819 fill_range_wc(subtable, wc, ofs.end);
1823 /* If we have narrowed down to a single rule already, check whether
1824 * that rule matches. Either way, we're done.
1826 * (Rare) hash collisions may cause us to miss the opportunity for this
1828 if (!cmap_node_next(inode)) {
1829 const struct cls_match *head;
1831 ASSIGN_CONTAINER(head, inode - i, index_nodes);
1832 if (miniflow_and_mask_matches_flow_wc(&head->flow, &subtable->mask,
1834 /* Return highest priority rule that is visible. */
1835 CLS_MATCH_FOR_EACH (rule, head) {
1836 if (OVS_LIKELY(cls_match_visible_in_version(rule,
1844 ofs.start = ofs.end;
1846 ofs.end = FLOW_U64S;
1847 /* Trie check for the final range. */
1848 if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow, wc)) {
1849 fill_range_wc(subtable, wc, ofs.start);
1852 hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
1854 rule = find_match(subtable, version, flow, hash);
1855 if (!rule && subtable->ports_mask_len) {
1856 /* Ports are always part of the final range, if any.
1857 * No match was found for the ports. Use the ports trie to figure out
1858 * which ports bits to unwildcard. */
1860 ovs_be32 value, plens, mask;
1862 mask = MINIFLOW_GET_BE32(&subtable->mask.masks, tp_src);
1863 value = ((OVS_FORCE ovs_be32 *)flow)[TP_PORTS_OFS32] & mask;
1864 mbits = trie_lookup_value(&subtable->ports_trie, &value, &plens, 32);
1866 ((OVS_FORCE ovs_be32 *)&wc->masks)[TP_PORTS_OFS32] |=
1867 mask & be32_prefix_mask(mbits);
1869 /* Unwildcard all bits in the mask upto the ports, as they were used
1870 * to determine there is no match. */
1871 fill_range_wc(subtable, wc, TP_PORTS_OFS64);
1875 /* Must unwildcard all the fields, as they were looked at. */
1876 flow_wildcards_fold_minimask(wc, &subtable->mask);
1880 static struct cls_match *
1881 find_equal(const struct cls_subtable *subtable, const struct miniflow *flow,
1884 struct cls_match *head;
1886 CMAP_FOR_EACH_WITH_HASH (head, cmap_node, hash, &subtable->rules) {
1887 if (miniflow_equal(&head->flow, flow)) {
1894 /* A longest-prefix match tree. */
1896 /* Return at least 'plen' bits of the 'prefix', starting at bit offset 'ofs'.
1897 * Prefixes are in the network byte order, and the offset 0 corresponds to
1898 * the most significant bit of the first byte. The offset can be read as
1899 * "how many bits to skip from the start of the prefix starting at 'pr'". */
1901 raw_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
1905 pr += ofs / 32; /* Where to start. */
1906 ofs %= 32; /* How many bits to skip at 'pr'. */
1908 prefix = ntohl(*pr) << ofs; /* Get the first 32 - ofs bits. */
1909 if (plen > 32 - ofs) { /* Need more than we have already? */
1910 prefix |= ntohl(*++pr) >> (32 - ofs);
1912 /* Return with possible unwanted bits at the end. */
1916 /* Return min(TRIE_PREFIX_BITS, plen) bits of the 'prefix', starting at bit
1917 * offset 'ofs'. Prefixes are in the network byte order, and the offset 0
1918 * corresponds to the most significant bit of the first byte. The offset can
1919 * be read as "how many bits to skip from the start of the prefix starting at
1922 trie_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
1927 if (plen > TRIE_PREFIX_BITS) {
1928 plen = TRIE_PREFIX_BITS; /* Get at most TRIE_PREFIX_BITS. */
1930 /* Return with unwanted bits cleared. */
1931 return raw_get_prefix(pr, ofs, plen) & ~0u << (32 - plen);
1934 /* Return the number of equal bits in 'n_bits' of 'prefix's MSBs and a 'value'
1935 * starting at "MSB 0"-based offset 'ofs'. */
1937 prefix_equal_bits(uint32_t prefix, unsigned int n_bits, const ovs_be32 value[],
1940 uint64_t diff = prefix ^ raw_get_prefix(value, ofs, n_bits);
1941 /* Set the bit after the relevant bits to limit the result. */
1942 return raw_clz64(diff << 32 | UINT64_C(1) << (63 - n_bits));
1945 /* Return the number of equal bits in 'node' prefix and a 'prefix' of length
1946 * 'plen', starting at "MSB 0"-based offset 'ofs'. */
1948 trie_prefix_equal_bits(const struct trie_node *node, const ovs_be32 prefix[],
1949 unsigned int ofs, unsigned int plen)
1951 return prefix_equal_bits(node->prefix, MIN(node->n_bits, plen - ofs),
1955 /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' can
1956 * be greater than 31. */
1958 be_get_bit_at(const ovs_be32 value[], unsigned int ofs)
1960 return (((const uint8_t *)value)[ofs / 8] >> (7 - ofs % 8)) & 1u;
1963 /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' must
1964 * be between 0 and 31, inclusive. */
1966 get_bit_at(const uint32_t prefix, unsigned int ofs)
1968 return (prefix >> (31 - ofs)) & 1u;
1971 /* Create new branch. */
1972 static struct trie_node *
1973 trie_branch_create(const ovs_be32 *prefix, unsigned int ofs, unsigned int plen,
1974 unsigned int n_rules)
1976 struct trie_node *node = xmalloc(sizeof *node);
1978 node->prefix = trie_get_prefix(prefix, ofs, plen);
1980 if (plen <= TRIE_PREFIX_BITS) {
1981 node->n_bits = plen;
1982 ovsrcu_set_hidden(&node->edges[0], NULL);
1983 ovsrcu_set_hidden(&node->edges[1], NULL);
1984 node->n_rules = n_rules;
1985 } else { /* Need intermediate nodes. */
1986 struct trie_node *subnode = trie_branch_create(prefix,
1987 ofs + TRIE_PREFIX_BITS,
1988 plen - TRIE_PREFIX_BITS,
1990 int bit = get_bit_at(subnode->prefix, 0);
1991 node->n_bits = TRIE_PREFIX_BITS;
1992 ovsrcu_set_hidden(&node->edges[bit], subnode);
1993 ovsrcu_set_hidden(&node->edges[!bit], NULL);
2000 trie_node_destroy(const struct trie_node *node)
2002 ovsrcu_postpone(free, CONST_CAST(struct trie_node *, node));
2005 /* Copy a trie node for modification and postpone delete the old one. */
2006 static struct trie_node *
2007 trie_node_rcu_realloc(const struct trie_node *node)
2009 struct trie_node *new_node = xmalloc(sizeof *node);
2012 trie_node_destroy(node);
2018 trie_destroy(rcu_trie_ptr *trie)
2020 struct trie_node *node = ovsrcu_get_protected(struct trie_node *, trie);
2023 ovsrcu_set_hidden(trie, NULL);
2024 trie_destroy(&node->edges[0]);
2025 trie_destroy(&node->edges[1]);
2026 trie_node_destroy(node);
2031 trie_is_leaf(const struct trie_node *trie)
2034 return !ovsrcu_get(struct trie_node *, &trie->edges[0])
2035 && !ovsrcu_get(struct trie_node *, &trie->edges[1]);
2039 mask_set_prefix_bits(struct flow_wildcards *wc, uint8_t be32ofs,
2040 unsigned int n_bits)
2042 ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
2045 for (i = 0; i < n_bits / 32; i++) {
2046 mask[i] = OVS_BE32_MAX;
2049 mask[i] |= htonl(~0u << (32 - n_bits % 32));
2054 mask_prefix_bits_set(const struct flow_wildcards *wc, uint8_t be32ofs,
2055 unsigned int n_bits)
2057 ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
2059 ovs_be32 zeroes = 0;
2061 for (i = 0; i < n_bits / 32; i++) {
2065 zeroes |= ~mask[i] & htonl(~0u << (32 - n_bits % 32));
2068 return !zeroes; /* All 'n_bits' bits set. */
2071 static rcu_trie_ptr *
2072 trie_next_edge(struct trie_node *node, const ovs_be32 value[],
2075 return node->edges + be_get_bit_at(value, ofs);
2078 static const struct trie_node *
2079 trie_next_node(const struct trie_node *node, const ovs_be32 value[],
2082 return ovsrcu_get(struct trie_node *,
2083 &node->edges[be_get_bit_at(value, ofs)]);
2086 /* Set the bit at ("MSB 0"-based) offset 'ofs'. 'ofs' can be greater than 31.
2089 be_set_bit_at(ovs_be32 value[], unsigned int ofs)
2091 ((uint8_t *)value)[ofs / 8] |= 1u << (7 - ofs % 8);
2094 /* Returns the number of bits in the prefix mask necessary to determine a
2095 * mismatch, in case there are longer prefixes in the tree below the one that
2097 * '*plens' will have a bit set for each prefix length that may have matching
2098 * rules. The caller is responsible for clearing the '*plens' prior to
2102 trie_lookup_value(const rcu_trie_ptr *trie, const ovs_be32 value[],
2103 ovs_be32 plens[], unsigned int n_bits)
2105 const struct trie_node *prev = NULL;
2106 const struct trie_node *node = ovsrcu_get(struct trie_node *, trie);
2107 unsigned int match_len = 0; /* Number of matching bits. */
2109 for (; node; prev = node, node = trie_next_node(node, value, match_len)) {
2110 unsigned int eqbits;
2111 /* Check if this edge can be followed. */
2112 eqbits = prefix_equal_bits(node->prefix, node->n_bits, value,
2114 match_len += eqbits;
2115 if (eqbits < node->n_bits) { /* Mismatch, nothing more to be found. */
2116 /* Bit at offset 'match_len' differed. */
2117 return match_len + 1; /* Includes the first mismatching bit. */
2119 /* Full match, check if rules exist at this prefix length. */
2120 if (node->n_rules > 0) {
2121 be_set_bit_at(plens, match_len - 1);
2123 if (match_len >= n_bits) {
2124 return n_bits; /* Full prefix. */
2127 /* node == NULL. Full match so far, but we tried to follow an
2128 * non-existing branch. Need to exclude the other branch if it exists
2129 * (it does not if we were called on an empty trie or 'prev' is a leaf
2131 return !prev || trie_is_leaf(prev) ? match_len : match_len + 1;
2135 trie_lookup(const struct cls_trie *trie, const struct flow *flow,
2136 union mf_value *plens)
2138 const struct mf_field *mf = trie->field;
2140 /* Check that current flow matches the prerequisites for the trie
2141 * field. Some match fields are used for multiple purposes, so we
2142 * must check that the trie is relevant for this flow. */
2143 if (mf_are_prereqs_ok(mf, flow)) {
2144 return trie_lookup_value(&trie->root,
2145 &((ovs_be32 *)flow)[mf->flow_be32ofs],
2146 &plens->be32, mf->n_bits);
2148 memset(plens, 0xff, sizeof *plens); /* All prefixes, no skipping. */
2149 return 0; /* Value not used in this case. */
2152 /* Returns the length of a prefix match mask for the field 'mf' in 'minimask'.
2153 * Returns the u32 offset to the miniflow data in '*miniflow_index', if
2154 * 'miniflow_index' is not NULL. */
2156 minimask_get_prefix_len(const struct minimask *minimask,
2157 const struct mf_field *mf)
2159 unsigned int n_bits = 0, mask_tz = 0; /* Non-zero when end of mask seen. */
2160 uint8_t be32_ofs = mf->flow_be32ofs;
2161 uint8_t be32_end = be32_ofs + mf->n_bytes / 4;
2163 for (; be32_ofs < be32_end; ++be32_ofs) {
2164 uint32_t mask = ntohl(minimask_get_be32(minimask, be32_ofs));
2166 /* Validate mask, count the mask length. */
2169 return 0; /* No bits allowed after mask ended. */
2172 if (~mask & (~mask + 1)) {
2173 return 0; /* Mask not contiguous. */
2175 mask_tz = ctz32(mask);
2176 n_bits += 32 - mask_tz;
2184 * This is called only when mask prefix is known to be CIDR and non-zero.
2185 * Relies on the fact that the flow and mask have the same map, and since
2186 * the mask is CIDR, the storage for the flow field exists even if it
2187 * happened to be zeros.
2189 static const ovs_be32 *
2190 minimatch_get_prefix(const struct minimatch *match, const struct mf_field *mf)
2192 return (OVS_FORCE const ovs_be32 *)
2193 (miniflow_get_values(&match->flow)
2194 + count_1bits(match->flow.map &
2195 ((UINT64_C(1) << mf->flow_be32ofs / 2) - 1)))
2196 + (mf->flow_be32ofs & 1);
2199 /* Insert rule in to the prefix tree.
2200 * 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2203 trie_insert(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
2205 trie_insert_prefix(&trie->root,
2206 minimatch_get_prefix(&rule->match, trie->field), mlen);
2210 trie_insert_prefix(rcu_trie_ptr *edge, const ovs_be32 *prefix, int mlen)
2212 struct trie_node *node;
2215 /* Walk the tree. */
2216 for (; (node = ovsrcu_get_protected(struct trie_node *, edge));
2217 edge = trie_next_edge(node, prefix, ofs)) {
2218 unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
2220 if (eqbits < node->n_bits) {
2221 /* Mismatch, new node needs to be inserted above. */
2222 int old_branch = get_bit_at(node->prefix, eqbits);
2223 struct trie_node *new_parent;
2225 new_parent = trie_branch_create(prefix, ofs - eqbits, eqbits,
2226 ofs == mlen ? 1 : 0);
2227 /* Copy the node to modify it. */
2228 node = trie_node_rcu_realloc(node);
2229 /* Adjust the new node for its new position in the tree. */
2230 node->prefix <<= eqbits;
2231 node->n_bits -= eqbits;
2232 ovsrcu_set_hidden(&new_parent->edges[old_branch], node);
2234 /* Check if need a new branch for the new rule. */
2236 ovsrcu_set_hidden(&new_parent->edges[!old_branch],
2237 trie_branch_create(prefix, ofs, mlen - ofs,
2240 ovsrcu_set(edge, new_parent); /* Publish changes. */
2243 /* Full match so far. */
2246 /* Full match at the current node, rule needs to be added here. */
2251 /* Must insert a new tree branch for the new rule. */
2252 ovsrcu_set(edge, trie_branch_create(prefix, ofs, mlen - ofs, 1));
2255 /* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2258 trie_remove(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
2260 trie_remove_prefix(&trie->root,
2261 minimatch_get_prefix(&rule->match, trie->field), mlen);
2264 /* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2267 trie_remove_prefix(rcu_trie_ptr *root, const ovs_be32 *prefix, int mlen)
2269 struct trie_node *node;
2270 rcu_trie_ptr *edges[sizeof(union mf_value) * 8];
2271 int depth = 0, ofs = 0;
2273 /* Walk the tree. */
2274 for (edges[0] = root;
2275 (node = ovsrcu_get_protected(struct trie_node *, edges[depth]));
2276 edges[++depth] = trie_next_edge(node, prefix, ofs)) {
2277 unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
2279 if (eqbits < node->n_bits) {
2280 /* Mismatch, nothing to be removed. This should never happen, as
2281 * only rules in the classifier are ever removed. */
2282 break; /* Log a warning. */
2284 /* Full match so far. */
2288 /* Full prefix match at the current node, remove rule here. */
2289 if (!node->n_rules) {
2290 break; /* Log a warning. */
2294 /* Check if can prune the tree. */
2295 while (!node->n_rules) {
2296 struct trie_node *next,
2297 *edge0 = ovsrcu_get_protected(struct trie_node *,
2299 *edge1 = ovsrcu_get_protected(struct trie_node *,
2302 if (edge0 && edge1) {
2303 break; /* A branching point, cannot prune. */
2306 /* Else have at most one child node, remove this node. */
2307 next = edge0 ? edge0 : edge1;
2310 if (node->n_bits + next->n_bits > TRIE_PREFIX_BITS) {
2311 break; /* Cannot combine. */
2313 next = trie_node_rcu_realloc(next); /* Modify. */
2315 /* Combine node with next. */
2316 next->prefix = node->prefix | next->prefix >> node->n_bits;
2317 next->n_bits += node->n_bits;
2319 /* Update the parent's edge. */
2320 ovsrcu_set(edges[depth], next); /* Publish changes. */
2321 trie_node_destroy(node);
2323 if (next || !depth) {
2324 /* Branch not pruned or at root, nothing more to do. */
2327 node = ovsrcu_get_protected(struct trie_node *,
2333 /* Cannot go deeper. This should never happen, since only rules
2334 * that actually exist in the classifier are ever removed. */
2335 VLOG_WARN("Trying to remove non-existing rule from a prefix trie.");
2339 #define CLS_MATCH_POISON (struct cls_match *)(UINTPTR_MAX / 0xf * 0xb)
2342 cls_match_free_cb(struct cls_match *rule)
2344 ovsrcu_set_hidden(&rule->next, CLS_MATCH_POISON);