2 * Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 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 "openvswitch/dynamic-string.h"
25 #include "openvswitch/ofp-util.h"
31 /* A collection of "struct cls_conjunction"s currently embedded into a
33 struct cls_conjunction_set {
34 /* Link back to the cls_match.
36 * cls_conjunction_set is mostly used during classifier lookup, and, in
37 * turn, during classifier lookup the most used member of
38 * cls_conjunction_set is the rule's priority, so we cache it here for fast
40 struct cls_match *match;
41 int priority; /* Cached copy of match->priority. */
43 /* Conjunction information.
45 * 'min_n_clauses' allows some optimization during classifier lookup. */
46 unsigned int n; /* Number of elements in 'conj'. */
47 unsigned int min_n_clauses; /* Smallest 'n' among elements of 'conj'. */
48 struct cls_conjunction conj[];
51 /* Ports trie depends on both ports sharing the same ovs_be32. */
52 #define TP_PORTS_OFS32 (offsetof(struct flow, tp_src) / 4)
53 BUILD_ASSERT_DECL(TP_PORTS_OFS32 == offsetof(struct flow, tp_dst) / 4);
54 BUILD_ASSERT_DECL(TP_PORTS_OFS32 % 2 == 0);
55 #define TP_PORTS_OFS64 (TP_PORTS_OFS32 / 2)
58 cls_conjunction_set_size(size_t n)
60 return (sizeof(struct cls_conjunction_set)
61 + n * sizeof(struct cls_conjunction));
64 static struct cls_conjunction_set *
65 cls_conjunction_set_alloc(struct cls_match *match,
66 const struct cls_conjunction conj[], size_t n)
69 size_t min_n_clauses = conj[0].n_clauses;
70 for (size_t i = 1; i < n; i++) {
71 min_n_clauses = MIN(min_n_clauses, conj[i].n_clauses);
74 struct cls_conjunction_set *set = xmalloc(cls_conjunction_set_size(n));
76 set->priority = match->priority;
78 set->min_n_clauses = min_n_clauses;
79 memcpy(set->conj, conj, n * sizeof *conj);
86 static struct cls_match *
87 cls_match_alloc(const struct cls_rule *rule, cls_version_t version,
88 const struct cls_conjunction conj[], size_t n)
90 size_t count = miniflow_n_values(rule->match.flow);
92 struct cls_match *cls_match
93 = xmalloc(sizeof *cls_match + MINIFLOW_VALUES_SIZE(count));
95 ovsrcu_init(&cls_match->next, NULL);
96 *CONST_CAST(const struct cls_rule **, &cls_match->cls_rule) = rule;
97 *CONST_CAST(int *, &cls_match->priority) = rule->priority;
98 *CONST_CAST(cls_version_t *, &cls_match->add_version) = version;
99 atomic_init(&cls_match->remove_version, version); /* Initially
101 miniflow_clone(CONST_CAST(struct miniflow *, &cls_match->flow),
102 rule->match.flow, count);
103 ovsrcu_set_hidden(&cls_match->conj_set,
104 cls_conjunction_set_alloc(cls_match, conj, n));
109 static struct cls_subtable *find_subtable(const struct classifier *cls,
110 const struct minimask *);
111 static struct cls_subtable *insert_subtable(struct classifier *cls,
112 const struct minimask *);
113 static void destroy_subtable(struct classifier *cls, struct cls_subtable *);
115 static const struct cls_match *find_match_wc(const struct cls_subtable *,
116 cls_version_t version,
119 unsigned int n_tries,
120 struct flow_wildcards *);
121 static struct cls_match *find_equal(const struct cls_subtable *,
122 const struct miniflow *, uint32_t hash);
124 /* Return the next visible (lower-priority) rule in the list. Multiple
125 * identical rules with the same priority may exist transitionally, but when
126 * versioning is used at most one of them is ever visible for lookups on any
127 * given 'version'. */
128 static inline const struct cls_match *
129 next_visible_rule_in_list(const struct cls_match *rule, cls_version_t version)
132 rule = cls_match_next(rule);
133 } while (rule && !cls_match_visible_in_version(rule, version));
138 /* Type with maximum supported prefix length. */
140 struct in6_addr ipv6; /* For sizing. */
141 ovs_be32 be32; /* For access. */
144 static unsigned int minimask_get_prefix_len(const struct minimask *,
145 const struct mf_field *);
146 static void trie_init(struct classifier *cls, int trie_idx,
147 const struct mf_field *);
148 static unsigned int trie_lookup(const struct cls_trie *, const struct flow *,
149 union trie_prefix *plens);
150 static unsigned int trie_lookup_value(const rcu_trie_ptr *,
151 const ovs_be32 value[], ovs_be32 plens[],
152 unsigned int value_bits);
153 static void trie_destroy(rcu_trie_ptr *);
154 static void trie_insert(struct cls_trie *, const struct cls_rule *, int mlen);
155 static void trie_insert_prefix(rcu_trie_ptr *, const ovs_be32 *prefix,
157 static void trie_remove(struct cls_trie *, const struct cls_rule *, int mlen);
158 static void trie_remove_prefix(rcu_trie_ptr *, const ovs_be32 *prefix,
160 static void mask_set_prefix_bits(struct flow_wildcards *, uint8_t be32ofs,
161 unsigned int n_bits);
162 static bool mask_prefix_bits_set(const struct flow_wildcards *,
163 uint8_t be32ofs, unsigned int n_bits);
168 cls_rule_init__(struct cls_rule *rule, unsigned int priority)
170 rculist_init(&rule->node);
171 *CONST_CAST(int *, &rule->priority) = priority;
172 ovsrcu_init(&rule->cls_match, NULL);
175 /* Initializes 'rule' to match packets specified by 'match' at the given
176 * 'priority'. 'match' must satisfy the invariant described in the comment at
177 * the definition of struct match.
179 * The caller must eventually destroy 'rule' with cls_rule_destroy().
181 * Clients should not use priority INT_MIN. (OpenFlow uses priorities between
182 * 0 and UINT16_MAX, inclusive.) */
184 cls_rule_init(struct cls_rule *rule, const struct match *match, int priority)
186 cls_rule_init__(rule, priority);
187 minimatch_init(CONST_CAST(struct minimatch *, &rule->match), match);
190 /* Same as cls_rule_init() for initialization from a "struct minimatch". */
192 cls_rule_init_from_minimatch(struct cls_rule *rule,
193 const struct minimatch *match, int priority)
195 cls_rule_init__(rule, priority);
196 minimatch_clone(CONST_CAST(struct minimatch *, &rule->match), match);
199 /* Initializes 'dst' as a copy of 'src'.
201 * The caller must eventually destroy 'dst' with cls_rule_destroy(). */
203 cls_rule_clone(struct cls_rule *dst, const struct cls_rule *src)
205 cls_rule_init__(dst, src->priority);
206 minimatch_clone(CONST_CAST(struct minimatch *, &dst->match), &src->match);
209 /* Initializes 'dst' with the data in 'src', destroying 'src'.
211 * 'src' must be a cls_rule NOT in a classifier.
213 * The caller must eventually destroy 'dst' with cls_rule_destroy(). */
215 cls_rule_move(struct cls_rule *dst, struct cls_rule *src)
217 cls_rule_init__(dst, src->priority);
218 minimatch_move(CONST_CAST(struct minimatch *, &dst->match),
219 CONST_CAST(struct minimatch *, &src->match));
222 /* Frees memory referenced by 'rule'. Doesn't free 'rule' itself (it's
223 * normally embedded into a larger structure).
225 * ('rule' must not currently be in a classifier.) */
227 cls_rule_destroy(struct cls_rule *rule)
228 OVS_NO_THREAD_SAFETY_ANALYSIS
230 /* Must not be in a classifier. */
231 ovs_assert(!get_cls_match_protected(rule));
233 /* Check that the rule has been properly removed from the classifier. */
234 ovs_assert(rule->node.prev == RCULIST_POISON
235 || rculist_is_empty(&rule->node));
236 rculist_poison__(&rule->node); /* Poisons also the next pointer. */
238 minimatch_destroy(CONST_CAST(struct minimatch *, &rule->match));
241 /* This may only be called by the exclusive writer. */
243 cls_rule_set_conjunctions(struct cls_rule *cr,
244 const struct cls_conjunction *conj, size_t n)
246 struct cls_match *match = get_cls_match_protected(cr);
247 struct cls_conjunction_set *old
248 = ovsrcu_get_protected(struct cls_conjunction_set *, &match->conj_set);
249 struct cls_conjunction *old_conj = old ? old->conj : NULL;
250 unsigned int old_n = old ? old->n : 0;
252 if (old_n != n || (n && memcmp(old_conj, conj, n * sizeof *conj))) {
254 ovsrcu_postpone(free, old);
256 ovsrcu_set(&match->conj_set,
257 cls_conjunction_set_alloc(match, conj, n));
262 /* Returns true if 'a' and 'b' match the same packets at the same priority,
263 * false if they differ in some way. */
265 cls_rule_equal(const struct cls_rule *a, const struct cls_rule *b)
267 return a->priority == b->priority && minimatch_equal(&a->match, &b->match);
270 /* Appends a string describing 'rule' to 's'. */
272 cls_rule_format(const struct cls_rule *rule, struct ds *s)
274 minimatch_format(&rule->match, s, rule->priority);
277 /* Returns true if 'rule' matches every packet, false otherwise. */
279 cls_rule_is_catchall(const struct cls_rule *rule)
281 return minimask_is_catchall(rule->match.mask);
284 /* Makes 'rule' invisible in 'remove_version'. Once that version is used in
285 * lookups, the caller should remove 'rule' via ovsrcu_postpone().
287 * 'rule' must be in a classifier.
288 * This may only be called by the exclusive writer. */
290 cls_rule_make_invisible_in_version(const struct cls_rule *rule,
291 cls_version_t remove_version)
293 struct cls_match *cls_match = get_cls_match_protected(rule);
295 ovs_assert(remove_version >= cls_match->add_version);
297 cls_match_set_remove_version(cls_match, remove_version);
300 /* This undoes the change made by cls_rule_make_invisible_in_version().
302 * 'rule' must be in a classifier.
303 * This may only be called by the exclusive writer. */
305 cls_rule_restore_visibility(const struct cls_rule *rule)
307 cls_match_set_remove_version(get_cls_match_protected(rule),
308 CLS_NOT_REMOVED_VERSION);
311 /* Return true if 'rule' is visible in 'version'.
313 * 'rule' must be in a classifier. */
315 cls_rule_visible_in_version(const struct cls_rule *rule, cls_version_t version)
317 struct cls_match *cls_match = get_cls_match(rule);
319 return cls_match && cls_match_visible_in_version(cls_match, version);
322 /* Initializes 'cls' as a classifier that initially contains no classification
325 classifier_init(struct classifier *cls, const uint8_t *flow_segments)
328 cmap_init(&cls->subtables_map);
329 pvector_init(&cls->subtables);
330 cls->n_flow_segments = 0;
332 while (cls->n_flow_segments < CLS_MAX_INDICES
333 && *flow_segments < FLOW_U64S) {
334 cls->flow_segments[cls->n_flow_segments++] = *flow_segments++;
338 for (int i = 0; i < CLS_MAX_TRIES; i++) {
339 trie_init(cls, i, NULL);
344 /* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
345 * caller's responsibility.
346 * May only be called after all the readers have been terminated. */
348 classifier_destroy(struct classifier *cls)
351 struct cls_subtable *subtable;
354 for (i = 0; i < cls->n_tries; i++) {
355 trie_destroy(&cls->tries[i].root);
358 CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
359 destroy_subtable(cls, subtable);
361 cmap_destroy(&cls->subtables_map);
363 pvector_destroy(&cls->subtables);
367 /* Set the fields for which prefix lookup should be performed. */
369 classifier_set_prefix_fields(struct classifier *cls,
370 const enum mf_field_id *trie_fields,
371 unsigned int n_fields)
373 const struct mf_field * new_fields[CLS_MAX_TRIES];
374 struct mf_bitmap fields = MF_BITMAP_INITIALIZER;
376 bool changed = false;
378 for (i = 0; i < n_fields && n_tries < CLS_MAX_TRIES; i++) {
379 const struct mf_field *field = mf_from_id(trie_fields[i]);
380 if (field->flow_be32ofs < 0 || field->n_bits % 32) {
381 /* Incompatible field. This is the only place where we
382 * enforce these requirements, but the rest of the trie code
383 * depends on the flow_be32ofs to be non-negative and the
384 * field length to be a multiple of 32 bits. */
388 if (bitmap_is_set(fields.bm, trie_fields[i])) {
389 /* Duplicate field, there is no need to build more than
390 * one index for any one field. */
393 bitmap_set1(fields.bm, trie_fields[i]);
395 new_fields[n_tries] = NULL;
396 if (n_tries >= cls->n_tries || field != cls->tries[n_tries].field) {
397 new_fields[n_tries] = field;
403 if (changed || n_tries < cls->n_tries) {
404 struct cls_subtable *subtable;
406 /* Trie configuration needs to change. Disable trie lookups
407 * for the tries that are changing and wait all the current readers
408 * with the old configuration to be done. */
410 CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
411 for (i = 0; i < cls->n_tries; i++) {
412 if ((i < n_tries && new_fields[i]) || i >= n_tries) {
413 if (subtable->trie_plen[i]) {
414 subtable->trie_plen[i] = 0;
420 /* Synchronize if any readers were using tries. The readers may
421 * temporarily function without the trie lookup based optimizations. */
423 /* ovsrcu_synchronize() functions as a memory barrier, so it does
424 * not matter that subtable->trie_plen is not atomic. */
425 ovsrcu_synchronize();
428 /* Now set up the tries. */
429 for (i = 0; i < n_tries; i++) {
431 trie_init(cls, i, new_fields[i]);
434 /* Destroy the rest, if any. */
435 for (; i < cls->n_tries; i++) {
436 trie_init(cls, i, NULL);
439 cls->n_tries = n_tries;
443 return false; /* No change. */
447 trie_init(struct classifier *cls, int trie_idx, const struct mf_field *field)
449 struct cls_trie *trie = &cls->tries[trie_idx];
450 struct cls_subtable *subtable;
452 if (trie_idx < cls->n_tries) {
453 trie_destroy(&trie->root);
455 ovsrcu_set_hidden(&trie->root, NULL);
459 /* Add existing rules to the new trie. */
460 CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
463 plen = field ? minimask_get_prefix_len(&subtable->mask, field) : 0;
465 struct cls_match *head;
467 CMAP_FOR_EACH (head, cmap_node, &subtable->rules) {
468 trie_insert(trie, head->cls_rule, plen);
471 /* Initialize subtable's prefix length on this field. This will
472 * allow readers to use the trie. */
473 atomic_thread_fence(memory_order_release);
474 subtable->trie_plen[trie_idx] = plen;
478 /* Returns true if 'cls' contains no classification rules, false otherwise.
479 * Checking the cmap requires no locking. */
481 classifier_is_empty(const struct classifier *cls)
483 return cmap_is_empty(&cls->subtables_map);
486 /* Returns the number of rules in 'cls'. */
488 classifier_count(const struct classifier *cls)
490 /* n_rules is an int, so in the presence of concurrent writers this will
491 * return either the old or a new value. */
495 static inline ovs_be32 minimatch_get_ports(const struct minimatch *match)
497 /* Could optimize to use the same map if needed for fast path. */
498 return MINIFLOW_GET_BE32(match->flow, tp_src)
499 & MINIFLOW_GET_BE32(&match->mask->masks, tp_src);
502 /* Inserts 'rule' into 'cls' in 'version'. Until 'rule' is removed from 'cls',
503 * the caller must not modify or free it.
505 * If 'cls' already contains an identical rule (including wildcards, values of
506 * fixed fields, and priority) that is visible in 'version', replaces the old
507 * rule by 'rule' and returns the rule that was replaced. The caller takes
508 * ownership of the returned rule and is thus responsible for destroying it
509 * with cls_rule_destroy(), after RCU grace period has passed (see
510 * ovsrcu_postpone()).
512 * Returns NULL if 'cls' does not contain a rule with an identical key, after
513 * inserting the new rule. In this case, no rules are displaced by the new
514 * rule, even rules that cannot have any effect because the new rule matches a
515 * superset of their flows and has higher priority.
517 const struct cls_rule *
518 classifier_replace(struct classifier *cls, const struct cls_rule *rule,
519 cls_version_t version,
520 const struct cls_conjunction *conjs, size_t n_conjs)
522 struct cls_match *new;
523 struct cls_subtable *subtable;
524 uint32_t ihash[CLS_MAX_INDICES];
525 struct cls_match *head;
526 unsigned int mask_offset;
532 /* 'new' is initially invisible to lookups. */
533 new = cls_match_alloc(rule, version, conjs, n_conjs);
534 ovsrcu_set(&CONST_CAST(struct cls_rule *, rule)->cls_match, new);
536 subtable = find_subtable(cls, rule->match.mask);
538 subtable = insert_subtable(cls, rule->match.mask);
541 /* Compute hashes in segments. */
544 for (i = 0; i < subtable->n_indices; i++) {
545 ihash[i] = minimatch_hash_range(&rule->match, subtable->index_maps[i],
546 &mask_offset, &basis);
548 hash = minimatch_hash_range(&rule->match, subtable->index_maps[i],
549 &mask_offset, &basis);
551 head = find_equal(subtable, rule->match.flow, hash);
553 /* Add rule to tries.
555 * Concurrent readers might miss seeing the rule until this update,
556 * which might require being fixed up by revalidation later. */
557 for (i = 0; i < cls->n_tries; i++) {
558 if (subtable->trie_plen[i]) {
559 trie_insert(&cls->tries[i], rule, subtable->trie_plen[i]);
563 /* Add rule to ports trie. */
564 if (subtable->ports_mask_len) {
565 /* We mask the value to be inserted to always have the wildcarded
566 * bits in known (zero) state, so we can include them in comparison
567 * and they will always match (== their original value does not
569 ovs_be32 masked_ports = minimatch_get_ports(&rule->match);
571 trie_insert_prefix(&subtable->ports_trie, &masked_ports,
572 subtable->ports_mask_len);
575 /* Add new node to segment indices. */
576 for (i = 0; i < subtable->n_indices; i++) {
577 ccmap_inc(&subtable->indices[i], ihash[i]);
579 n_rules = cmap_insert(&subtable->rules, &new->cmap_node, hash);
580 } else { /* Equal rules exist in the classifier already. */
581 struct cls_match *prev, *iter;
583 /* Scan the list for the insertion point that will keep the list in
584 * order of decreasing priority. Insert after rules marked invisible
585 * in any version of the same priority. */
586 FOR_EACH_RULE_IN_LIST_PROTECTED (iter, prev, head) {
587 if (rule->priority > iter->priority
588 || (rule->priority == iter->priority
589 && !cls_match_is_eventually_invisible(iter))) {
594 /* Replace 'iter' with 'new' or insert 'new' between 'prev' and
597 struct cls_rule *old;
599 if (rule->priority == iter->priority) {
600 cls_match_replace(prev, iter, new);
601 old = CONST_CAST(struct cls_rule *, iter->cls_rule);
603 cls_match_insert(prev, iter, new);
607 /* Replace the existing head in data structures, if rule is the new
610 cmap_replace(&subtable->rules, &head->cmap_node,
611 &new->cmap_node, hash);
615 struct cls_conjunction_set *conj_set;
617 conj_set = ovsrcu_get_protected(struct cls_conjunction_set *,
620 ovsrcu_postpone(free, conj_set);
623 ovsrcu_set(&old->cls_match, NULL); /* Marks old rule as removed
624 * from the classifier. */
625 ovsrcu_postpone(cls_match_free_cb, iter);
627 /* No change in subtable's max priority or max count. */
629 /* Make 'new' visible to lookups in the appropriate version. */
630 cls_match_set_remove_version(new, CLS_NOT_REMOVED_VERSION);
632 /* Make rule visible to iterators (immediately). */
633 rculist_replace(CONST_CAST(struct rculist *, &rule->node),
636 /* Return displaced rule. Caller is responsible for keeping it
637 * around until all threads quiesce. */
641 /* 'new' is new node after 'prev' */
642 cls_match_insert(prev, iter, new);
646 /* Make 'new' visible to lookups in the appropriate version. */
647 cls_match_set_remove_version(new, CLS_NOT_REMOVED_VERSION);
649 /* Make rule visible to iterators (immediately). */
650 rculist_push_back(&subtable->rules_list,
651 CONST_CAST(struct rculist *, &rule->node));
653 /* Rule was added, not replaced. Update 'subtable's 'max_priority' and
654 * 'max_count', if necessary.
656 * The rule was already inserted, but concurrent readers may not see the
657 * rule yet as the subtables vector is not updated yet. This will have to
658 * be fixed by revalidation later. */
660 subtable->max_priority = rule->priority;
661 subtable->max_count = 1;
662 pvector_insert(&cls->subtables, subtable, rule->priority);
663 } else if (rule->priority == subtable->max_priority) {
664 ++subtable->max_count;
665 } else if (rule->priority > subtable->max_priority) {
666 subtable->max_priority = rule->priority;
667 subtable->max_count = 1;
668 pvector_change_priority(&cls->subtables, subtable, rule->priority);
671 /* Nothing was replaced. */
675 pvector_publish(&cls->subtables);
681 /* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller
682 * must not modify or free it.
684 * 'cls' must not contain an identical rule (including wildcards, values of
685 * fixed fields, and priority). Use classifier_find_rule_exactly() to find
688 classifier_insert(struct classifier *cls, const struct cls_rule *rule,
689 cls_version_t version, const struct cls_conjunction conj[],
692 const struct cls_rule *displaced_rule
693 = classifier_replace(cls, rule, version, conj, n_conj);
694 ovs_assert(!displaced_rule);
697 /* Removes 'rule' from 'cls'. It is the caller's responsibility to destroy
698 * 'rule' with cls_rule_destroy(), freeing the memory block in which 'rule'
699 * resides, etc., as necessary.
701 * Does nothing if 'rule' has been already removed, or was never inserted.
703 * Returns the removed rule, or NULL, if it was already removed.
705 const struct cls_rule *
706 classifier_remove(struct classifier *cls, const struct cls_rule *cls_rule)
708 struct cls_match *rule, *prev, *next, *head;
709 struct cls_conjunction_set *conj_set;
710 struct cls_subtable *subtable;
711 uint32_t basis = 0, hash, ihash[CLS_MAX_INDICES];
712 unsigned int mask_offset;
716 rule = get_cls_match_protected(cls_rule);
720 /* Mark as removed. */
721 ovsrcu_set(&CONST_CAST(struct cls_rule *, cls_rule)->cls_match, NULL);
723 /* Remove 'cls_rule' from the subtable's rules list. */
724 rculist_remove(CONST_CAST(struct rculist *, &cls_rule->node));
726 subtable = find_subtable(cls, cls_rule->match.mask);
727 ovs_assert(subtable);
730 for (i = 0; i < subtable->n_indices; i++) {
731 ihash[i] = minimatch_hash_range(&cls_rule->match,
732 subtable->index_maps[i],
733 &mask_offset, &basis);
735 hash = minimatch_hash_range(&cls_rule->match, subtable->index_maps[i],
736 &mask_offset, &basis);
738 head = find_equal(subtable, cls_rule->match.flow, hash);
740 /* Check if the rule is not the head rule. */
742 struct cls_match *iter;
744 /* Not the head rule, but potentially one with the same priority. */
745 /* Remove from the list of equal rules. */
746 FOR_EACH_RULE_IN_LIST_PROTECTED (iter, prev, head) {
751 ovs_assert(iter == rule);
753 cls_match_remove(prev, rule);
758 /* 'rule' is the head rule. Check if there is another rule to
759 * replace 'rule' in the data structures. */
760 next = cls_match_next_protected(rule);
762 cmap_replace(&subtable->rules, &rule->cmap_node, &next->cmap_node,
767 /* 'rule' is last of the kind in the classifier, must remove from all the
768 * data structures. */
770 if (subtable->ports_mask_len) {
771 ovs_be32 masked_ports = minimatch_get_ports(&cls_rule->match);
773 trie_remove_prefix(&subtable->ports_trie,
774 &masked_ports, subtable->ports_mask_len);
776 for (i = 0; i < cls->n_tries; i++) {
777 if (subtable->trie_plen[i]) {
778 trie_remove(&cls->tries[i], cls_rule, subtable->trie_plen[i]);
782 /* Remove rule node from indices. */
783 for (i = 0; i < subtable->n_indices; i++) {
784 ccmap_dec(&subtable->indices[i], ihash[i]);
786 n_rules = cmap_remove(&subtable->rules, &rule->cmap_node, hash);
789 destroy_subtable(cls, subtable);
792 if (subtable->max_priority == rule->priority
793 && --subtable->max_count == 0) {
794 /* Find the new 'max_priority' and 'max_count'. */
795 int max_priority = INT_MIN;
796 struct cls_match *head;
798 CMAP_FOR_EACH (head, cmap_node, &subtable->rules) {
799 if (head->priority > max_priority) {
800 max_priority = head->priority;
801 subtable->max_count = 1;
802 } else if (head->priority == max_priority) {
803 ++subtable->max_count;
806 subtable->max_priority = max_priority;
807 pvector_change_priority(&cls->subtables, subtable, max_priority);
812 pvector_publish(&cls->subtables);
816 conj_set = ovsrcu_get_protected(struct cls_conjunction_set *,
819 ovsrcu_postpone(free, conj_set);
821 ovsrcu_postpone(cls_match_free_cb, rule);
827 /* Prefix tree context. Valid when 'lookup_done' is true. Can skip all
828 * subtables which have a prefix match on the trie field, but whose prefix
829 * length is not indicated in 'match_plens'. For example, a subtable that
830 * has a 8-bit trie field prefix match can be skipped if
831 * !be_get_bit_at(&match_plens, 8 - 1). If skipped, 'maskbits' prefix bits
832 * must be unwildcarded to make datapath flow only match packets it should. */
834 const struct cls_trie *trie;
835 bool lookup_done; /* Status of the lookup. */
836 uint8_t be32ofs; /* U32 offset of the field in question. */
837 unsigned int maskbits; /* Prefix length needed to avoid false matches. */
838 union trie_prefix match_plens; /* Bitmask of prefix lengths with possible
843 trie_ctx_init(struct trie_ctx *ctx, const struct cls_trie *trie)
846 ctx->be32ofs = trie->field->flow_be32ofs;
847 ctx->lookup_done = false;
850 struct conjunctive_match {
851 struct hmap_node hmap_node;
856 static struct conjunctive_match *
857 find_conjunctive_match__(struct hmap *matches, uint64_t id, uint32_t hash)
859 struct conjunctive_match *m;
861 HMAP_FOR_EACH_IN_BUCKET (m, hmap_node, hash, matches) {
870 find_conjunctive_match(const struct cls_conjunction_set *set,
871 unsigned int max_n_clauses, struct hmap *matches,
872 struct conjunctive_match *cm_stubs, size_t n_cm_stubs,
875 const struct cls_conjunction *c;
877 if (max_n_clauses < set->min_n_clauses) {
881 for (c = set->conj; c < &set->conj[set->n]; c++) {
882 struct conjunctive_match *cm;
885 if (c->n_clauses > max_n_clauses) {
889 hash = hash_int(c->id, 0);
890 cm = find_conjunctive_match__(matches, c->id, hash);
892 size_t n = hmap_count(matches);
894 cm = n < n_cm_stubs ? &cm_stubs[n] : xmalloc(sizeof *cm);
895 hmap_insert(matches, &cm->hmap_node, hash);
897 cm->clauses = UINT64_MAX << (c->n_clauses & 63);
899 cm->clauses |= UINT64_C(1) << c->clause;
900 if (cm->clauses == UINT64_MAX) {
909 free_conjunctive_matches(struct hmap *matches,
910 struct conjunctive_match *cm_stubs, size_t n_cm_stubs)
912 if (hmap_count(matches) > n_cm_stubs) {
913 struct conjunctive_match *cm, *next;
915 HMAP_FOR_EACH_SAFE (cm, next, hmap_node, matches) {
916 if (!(cm >= cm_stubs && cm < &cm_stubs[n_cm_stubs])) {
921 hmap_destroy(matches);
924 /* Like classifier_lookup(), except that support for conjunctive matches can be
925 * configured with 'allow_conjunctive_matches'. That feature is not exposed
926 * externally because turning off conjunctive matches is only useful to avoid
927 * recursion within this function itself.
929 * 'flow' is non-const to allow for temporary modifications during the lookup.
930 * Any changes are restored before returning. */
931 static const struct cls_rule *
932 classifier_lookup__(const struct classifier *cls, cls_version_t version,
933 struct flow *flow, struct flow_wildcards *wc,
934 bool allow_conjunctive_matches)
936 struct trie_ctx trie_ctx[CLS_MAX_TRIES];
937 const struct cls_match *match;
938 /* Highest-priority flow in 'cls' that certainly matches 'flow'. */
939 const struct cls_match *hard = NULL;
940 int hard_pri = INT_MIN; /* hard ? hard->priority : INT_MIN. */
942 /* Highest-priority conjunctive flows in 'cls' matching 'flow'. Since
943 * these are (components of) conjunctive flows, we can only know whether
944 * the full conjunctive flow matches after seeing multiple of them. Thus,
945 * we refer to these as "soft matches". */
946 struct cls_conjunction_set *soft_stub[64];
947 struct cls_conjunction_set **soft = soft_stub;
948 size_t n_soft = 0, allocated_soft = ARRAY_SIZE(soft_stub);
949 int soft_pri = INT_MIN; /* n_soft ? MAX(soft[*]->priority) : INT_MIN. */
951 /* Synchronize for cls->n_tries and subtable->trie_plen. They can change
952 * when table configuration changes, which happens typically only on
954 atomic_thread_fence(memory_order_acquire);
956 /* Initialize trie contexts for find_match_wc(). */
957 for (int i = 0; i < cls->n_tries; i++) {
958 trie_ctx_init(&trie_ctx[i], &cls->tries[i]);
962 struct cls_subtable *subtable;
963 PVECTOR_FOR_EACH_PRIORITY (subtable, hard_pri, 2, sizeof *subtable,
965 struct cls_conjunction_set *conj_set;
967 /* Skip subtables with no match, or where the match is lower-priority
968 * than some certain match we've already found. */
969 match = find_match_wc(subtable, version, flow, trie_ctx, cls->n_tries,
971 if (!match || match->priority <= hard_pri) {
975 conj_set = ovsrcu_get(struct cls_conjunction_set *, &match->conj_set);
977 /* 'match' isn't part of a conjunctive match. It's the best
978 * certain match we've got so far, since we know that it's
979 * higher-priority than hard_pri.
981 * (There might be a higher-priority conjunctive match. We can't
984 hard_pri = hard->priority;
985 } else if (allow_conjunctive_matches) {
986 /* 'match' is part of a conjunctive match. Add it to the list. */
987 if (OVS_UNLIKELY(n_soft >= allocated_soft)) {
988 struct cls_conjunction_set **old_soft = soft;
991 soft = xmalloc(allocated_soft * sizeof *soft);
992 memcpy(soft, old_soft, n_soft * sizeof *soft);
993 if (old_soft != soft_stub) {
997 soft[n_soft++] = conj_set;
999 /* Keep track of the highest-priority soft match. */
1000 if (soft_pri < match->priority) {
1001 soft_pri = match->priority;
1006 /* In the common case, at this point we have no soft matches and we can
1007 * return immediately. (We do the same thing if we have potential soft
1008 * matches but none of them are higher-priority than our hard match.) */
1009 if (hard_pri >= soft_pri) {
1010 if (soft != soft_stub) {
1013 return hard ? hard->cls_rule : NULL;
1016 /* At this point, we have some soft matches. We might also have a hard
1017 * match; if so, its priority is lower than the highest-priority soft
1022 * Check whether soft matches are real matches. */
1024 /* Delete soft matches that are null. This only happens in second and
1025 * subsequent iterations of the soft match loop, when we drop back from
1026 * a high-priority soft match to a lower-priority one.
1028 * Also, delete soft matches whose priority is less than or equal to
1029 * the hard match's priority. In the first iteration of the soft
1030 * match, these can be in 'soft' because the earlier main loop found
1031 * the soft match before the hard match. In second and later iteration
1032 * of the soft match loop, these can be in 'soft' because we dropped
1033 * back from a high-priority soft match to a lower-priority soft match.
1035 * It is tempting to delete soft matches that cannot be satisfied
1036 * because there are fewer soft matches than required to satisfy any of
1037 * their conjunctions, but we cannot do that because there might be
1038 * lower priority soft or hard matches with otherwise identical
1039 * matches. (We could special case those here, but there's no
1040 * need--we'll do so at the bottom of the soft match loop anyway and
1041 * this duplicates less code.)
1043 * It's also tempting to break out of the soft match loop if 'n_soft ==
1044 * 1' but that would also miss lower-priority hard matches. We could
1045 * special case that also but again there's no need. */
1046 for (int i = 0; i < n_soft; ) {
1047 if (!soft[i] || soft[i]->priority <= hard_pri) {
1048 soft[i] = soft[--n_soft];
1057 /* Find the highest priority among the soft matches. (We know this
1058 * must be higher than the hard match's priority; otherwise we would
1059 * have deleted all of the soft matches in the previous loop.) Count
1060 * the number of soft matches that have that priority. */
1063 for (int i = 0; i < n_soft; i++) {
1064 if (soft[i]->priority > soft_pri) {
1065 soft_pri = soft[i]->priority;
1067 } else if (soft[i]->priority == soft_pri) {
1071 ovs_assert(soft_pri > hard_pri);
1073 /* Look for a real match among the highest-priority soft matches.
1075 * It's unusual to have many conjunctive matches, so we use stubs to
1076 * avoid calling malloc() in the common case. An hmap has a built-in
1077 * stub for up to 2 hmap_nodes; possibly, we would benefit a variant
1078 * with a bigger stub. */
1079 struct conjunctive_match cm_stubs[16];
1080 struct hmap matches;
1082 hmap_init(&matches);
1083 for (int i = 0; i < n_soft; i++) {
1086 if (soft[i]->priority == soft_pri
1087 && find_conjunctive_match(soft[i], n_soft_pri, &matches,
1088 cm_stubs, ARRAY_SIZE(cm_stubs),
1090 uint32_t saved_conj_id = flow->conj_id;
1091 const struct cls_rule *rule;
1094 rule = classifier_lookup__(cls, version, flow, wc, false);
1095 flow->conj_id = saved_conj_id;
1098 free_conjunctive_matches(&matches,
1099 cm_stubs, ARRAY_SIZE(cm_stubs));
1100 if (soft != soft_stub) {
1107 free_conjunctive_matches(&matches, cm_stubs, ARRAY_SIZE(cm_stubs));
1109 /* There's no real match among the highest-priority soft matches.
1110 * However, if any of those soft matches has a lower-priority but
1111 * otherwise identical flow match, then we need to consider those for
1112 * soft or hard matches.
1114 * The next iteration of the soft match loop will delete any null
1115 * pointers we put into 'soft' (and some others too). */
1116 for (int i = 0; i < n_soft; i++) {
1117 if (soft[i]->priority != soft_pri) {
1121 /* Find next-lower-priority flow with identical flow match. */
1122 match = next_visible_rule_in_list(soft[i]->match, version);
1124 soft[i] = ovsrcu_get(struct cls_conjunction_set *,
1127 /* The flow is a hard match; don't treat as a soft
1129 if (match->priority > hard_pri) {
1131 hard_pri = hard->priority;
1135 /* No such lower-priority flow (probably the common case). */
1141 if (soft != soft_stub) {
1144 return hard ? hard->cls_rule : NULL;
1147 /* Finds and returns the highest-priority rule in 'cls' that matches 'flow' and
1148 * that is visible in 'version'. Returns a null pointer if no rules in 'cls'
1149 * match 'flow'. If multiple rules of equal priority match 'flow', returns one
1152 * If a rule is found and 'wc' is non-null, bitwise-OR's 'wc' with the
1153 * set of bits that were significant in the lookup. At some point
1154 * earlier, 'wc' should have been initialized (e.g., by
1155 * flow_wildcards_init_catchall()).
1157 * 'flow' is non-const to allow for temporary modifications during the lookup.
1158 * Any changes are restored before returning. */
1159 const struct cls_rule *
1160 classifier_lookup(const struct classifier *cls, cls_version_t version,
1161 struct flow *flow, struct flow_wildcards *wc)
1163 return classifier_lookup__(cls, version, flow, wc, true);
1166 /* Finds and returns a rule in 'cls' with exactly the same priority and
1167 * matching criteria as 'target', and that is visible in 'version'.
1168 * Only one such rule may ever exist. Returns a null pointer if 'cls' doesn't
1169 * contain an exact match. */
1170 const struct cls_rule *
1171 classifier_find_rule_exactly(const struct classifier *cls,
1172 const struct cls_rule *target,
1173 cls_version_t version)
1175 const struct cls_match *head, *rule;
1176 const struct cls_subtable *subtable;
1178 subtable = find_subtable(cls, target->match.mask);
1183 head = find_equal(subtable, target->match.flow,
1184 miniflow_hash_in_minimask(target->match.flow,
1185 target->match.mask, 0));
1189 CLS_MATCH_FOR_EACH (rule, head) {
1190 if (rule->priority < target->priority) {
1191 break; /* Not found. */
1193 if (rule->priority == target->priority
1194 && cls_match_visible_in_version(rule, version)) {
1195 return rule->cls_rule;
1201 /* Finds and returns a rule in 'cls' with priority 'priority' and exactly the
1202 * same matching criteria as 'target', and that is visible in 'version'.
1203 * Returns a null pointer if 'cls' doesn't contain an exact match visible in
1205 const struct cls_rule *
1206 classifier_find_match_exactly(const struct classifier *cls,
1207 const struct match *target, int priority,
1208 cls_version_t version)
1210 const struct cls_rule *retval;
1213 cls_rule_init(&cr, target, priority);
1214 retval = classifier_find_rule_exactly(cls, &cr, version);
1215 cls_rule_destroy(&cr);
1220 /* Checks if 'target' would overlap any other rule in 'cls' in 'version'. Two
1221 * rules are considered to overlap if both rules have the same priority and a
1222 * packet could match both, and if both rules are visible in the same version.
1224 * A trivial example of overlapping rules is two rules matching disjoint sets
1225 * of fields. E.g., if one rule matches only on port number, while another only
1226 * on dl_type, any packet from that specific port and with that specific
1227 * dl_type could match both, if the rules also have the same priority. */
1229 classifier_rule_overlaps(const struct classifier *cls,
1230 const struct cls_rule *target, cls_version_t version)
1232 struct cls_subtable *subtable;
1234 /* Iterate subtables in the descending max priority order. */
1235 PVECTOR_FOR_EACH_PRIORITY (subtable, target->priority - 1, 2,
1236 sizeof(struct cls_subtable), &cls->subtables) {
1238 struct minimask mask;
1239 uint64_t storage[FLOW_U64S];
1241 const struct cls_rule *rule;
1243 minimask_combine(&m.mask, target->match.mask, &subtable->mask,
1246 RCULIST_FOR_EACH (rule, node, &subtable->rules_list) {
1247 if (rule->priority == target->priority
1248 && miniflow_equal_in_minimask(target->match.flow,
1249 rule->match.flow, &m.mask)
1250 && cls_rule_visible_in_version(rule, version)) {
1258 /* Returns true if 'rule' exactly matches 'criteria' or if 'rule' is more
1259 * specific than 'criteria'. That is, 'rule' matches 'criteria' and this
1260 * function returns true if, for every field:
1262 * - 'criteria' and 'rule' specify the same (non-wildcarded) value for the
1265 * - 'criteria' wildcards the field,
1267 * Conversely, 'rule' does not match 'criteria' and this function returns false
1268 * if, for at least one field:
1270 * - 'criteria' and 'rule' specify different values for the field, or
1272 * - 'criteria' specifies a value for the field but 'rule' wildcards it.
1274 * Equivalently, the truth table for whether a field matches is:
1279 * r +---------+---------+
1280 * i wild | yes | yes |
1282 * e +---------+---------+
1283 * r exact | no |if values|
1285 * a +---------+---------+
1287 * This is the matching rule used by OpenFlow 1.0 non-strict OFPT_FLOW_MOD
1288 * commands and by OpenFlow 1.0 aggregate and flow stats.
1290 * Ignores rule->priority. */
1292 cls_rule_is_loose_match(const struct cls_rule *rule,
1293 const struct minimatch *criteria)
1295 return (!minimask_has_extra(rule->match.mask, criteria->mask)
1296 && miniflow_equal_in_minimask(rule->match.flow, criteria->flow,
1303 rule_matches(const struct cls_rule *rule, const struct cls_rule *target,
1304 cls_version_t version)
1306 /* Rule may only match a target if it is visible in target's version. */
1307 return cls_rule_visible_in_version(rule, version)
1308 && (!target || miniflow_equal_in_minimask(rule->match.flow,
1310 target->match.mask));
1313 static const struct cls_rule *
1314 search_subtable(const struct cls_subtable *subtable,
1315 struct cls_cursor *cursor)
1318 || !minimask_has_extra(&subtable->mask, cursor->target->match.mask)) {
1319 const struct cls_rule *rule;
1321 RCULIST_FOR_EACH (rule, node, &subtable->rules_list) {
1322 if (rule_matches(rule, cursor->target, cursor->version)) {
1330 /* Initializes 'cursor' for iterating through rules in 'cls', and returns the
1333 * - If 'target' is null, or if the 'target' is a catchall target, the
1334 * cursor will visit every rule in 'cls' that is visible in 'version'.
1336 * - If 'target' is nonnull, the cursor will visit each 'rule' in 'cls'
1337 * such that cls_rule_is_loose_match(rule, target) returns true and that
1338 * the rule is visible in 'version'.
1340 * Ignores target->priority. */
1342 cls_cursor_start(const struct classifier *cls, const struct cls_rule *target,
1343 cls_version_t version)
1345 struct cls_cursor cursor;
1346 struct cls_subtable *subtable;
1349 cursor.target = target && !cls_rule_is_catchall(target) ? target : NULL;
1350 cursor.version = version;
1353 /* Find first rule. */
1354 PVECTOR_CURSOR_FOR_EACH (subtable, &cursor.subtables,
1355 &cursor.cls->subtables) {
1356 const struct cls_rule *rule = search_subtable(subtable, &cursor);
1359 cursor.subtable = subtable;
1368 static const struct cls_rule *
1369 cls_cursor_next(struct cls_cursor *cursor)
1371 const struct cls_rule *rule;
1372 const struct cls_subtable *subtable;
1374 rule = cursor->rule;
1375 subtable = cursor->subtable;
1376 RCULIST_FOR_EACH_CONTINUE (rule, node, &subtable->rules_list) {
1377 if (rule_matches(rule, cursor->target, cursor->version)) {
1382 PVECTOR_CURSOR_FOR_EACH_CONTINUE (subtable, &cursor->subtables) {
1383 rule = search_subtable(subtable, cursor);
1385 cursor->subtable = subtable;
1393 /* Sets 'cursor->rule' to the next matching cls_rule in 'cursor''s iteration,
1394 * or to null if all matching rules have been visited. */
1396 cls_cursor_advance(struct cls_cursor *cursor)
1398 cursor->rule = cls_cursor_next(cursor);
1401 static struct cls_subtable *
1402 find_subtable(const struct classifier *cls, const struct minimask *mask)
1404 struct cls_subtable *subtable;
1406 CMAP_FOR_EACH_WITH_HASH (subtable, cmap_node, minimask_hash(mask, 0),
1407 &cls->subtables_map) {
1408 if (minimask_equal(mask, &subtable->mask)) {
1415 /* Initializes 'map' with a subset of 'miniflow''s maps that includes only the
1416 * portions with u64-offset 'i' such that 'start' <= i < 'end'. Does not copy
1417 * any data from 'miniflow' to 'map'. */
1418 static struct flowmap
1419 miniflow_get_map_in_range(const struct miniflow *miniflow, uint8_t start,
1425 map = miniflow->map;
1427 /* Clear the bits before 'start'. */
1428 while (start >= MAP_T_BITS) {
1429 start -= MAP_T_BITS;
1431 map.bits[start / MAP_T_BITS] = 0;
1434 flowmap_clear(&map, ofs, start);
1437 /* Clear the bits starting at 'end'. */
1438 if (end < FLOW_U64S) {
1439 /* flowmap_clear() can handle at most MAP_T_BITS at a time. */
1440 ovs_assert(FLOW_U64S - end <= MAP_T_BITS);
1441 flowmap_clear(&map, end, FLOW_U64S - end);
1446 /* The new subtable will be visible to the readers only after this. */
1447 static struct cls_subtable *
1448 insert_subtable(struct classifier *cls, const struct minimask *mask)
1450 uint32_t hash = minimask_hash(mask, 0);
1451 struct cls_subtable *subtable;
1453 struct flowmap stage_map;
1455 size_t count = miniflow_n_values(&mask->masks);
1457 subtable = xzalloc(sizeof *subtable + MINIFLOW_VALUES_SIZE(count));
1458 cmap_init(&subtable->rules);
1459 miniflow_clone(CONST_CAST(struct miniflow *, &subtable->mask.masks),
1460 &mask->masks, count);
1462 /* Init indices for segmented lookup, if any. */
1464 for (i = 0; i < cls->n_flow_segments; i++) {
1465 stage_map = miniflow_get_map_in_range(&mask->masks, prev,
1466 cls->flow_segments[i]);
1467 /* Add an index if it adds mask bits. */
1468 if (!flowmap_is_empty(stage_map)) {
1469 ccmap_init(&subtable->indices[index]);
1470 *CONST_CAST(struct flowmap *, &subtable->index_maps[index])
1474 prev = cls->flow_segments[i];
1476 /* Map for the final stage. */
1477 *CONST_CAST(struct flowmap *, &subtable->index_maps[index])
1478 = miniflow_get_map_in_range(&mask->masks, prev, FLOW_U64S);
1479 /* Check if the final stage adds any bits. */
1481 if (flowmap_is_empty(subtable->index_maps[index])) {
1482 /* Remove the last index, as it has the same fields as the rules
1485 ccmap_destroy(&subtable->indices[index]);
1488 *CONST_CAST(uint8_t *, &subtable->n_indices) = index;
1490 for (i = 0; i < cls->n_tries; i++) {
1491 subtable->trie_plen[i] = minimask_get_prefix_len(mask,
1492 cls->tries[i].field);
1496 ovsrcu_set_hidden(&subtable->ports_trie, NULL);
1497 *CONST_CAST(int *, &subtable->ports_mask_len)
1498 = 32 - ctz32(ntohl(MINIFLOW_GET_BE32(&mask->masks, tp_src)));
1500 /* List of rules. */
1501 rculist_init(&subtable->rules_list);
1503 cmap_insert(&cls->subtables_map, &subtable->cmap_node, hash);
1508 /* RCU readers may still access the subtable before it is actually freed. */
1510 destroy_subtable(struct classifier *cls, struct cls_subtable *subtable)
1514 pvector_remove(&cls->subtables, subtable);
1515 cmap_remove(&cls->subtables_map, &subtable->cmap_node,
1516 minimask_hash(&subtable->mask, 0));
1518 ovs_assert(ovsrcu_get_protected(struct trie_node *, &subtable->ports_trie)
1520 ovs_assert(cmap_is_empty(&subtable->rules));
1521 ovs_assert(rculist_is_empty(&subtable->rules_list));
1523 for (i = 0; i < subtable->n_indices; i++) {
1524 ccmap_destroy(&subtable->indices[i]);
1526 cmap_destroy(&subtable->rules);
1527 ovsrcu_postpone(free, subtable);
1530 static unsigned int be_get_bit_at(const ovs_be32 value[], unsigned int ofs);
1532 /* Return 'true' if can skip rest of the subtable based on the prefix trie
1533 * lookup results. */
1535 check_tries(struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries,
1536 const unsigned int field_plen[CLS_MAX_TRIES],
1537 const struct flowmap range_map, const struct flow *flow,
1538 struct flow_wildcards *wc)
1542 /* Check if we could avoid fully unwildcarding the next level of
1543 * fields using the prefix tries. The trie checks are done only as
1544 * needed to avoid folding in additional bits to the wildcards mask. */
1545 for (j = 0; j < n_tries; j++) {
1546 /* Is the trie field relevant for this subtable, and
1547 is the trie field within the current range of fields? */
1548 if (field_plen[j] &&
1549 flowmap_is_set(&range_map, trie_ctx[j].be32ofs / 2)) {
1550 struct trie_ctx *ctx = &trie_ctx[j];
1552 /* On-demand trie lookup. */
1553 if (!ctx->lookup_done) {
1554 memset(&ctx->match_plens, 0, sizeof ctx->match_plens);
1555 ctx->maskbits = trie_lookup(ctx->trie, flow, &ctx->match_plens);
1556 ctx->lookup_done = true;
1558 /* Possible to skip the rest of the subtable if subtable's
1559 * prefix on the field is not included in the lookup result. */
1560 if (!be_get_bit_at(&ctx->match_plens.be32, field_plen[j] - 1)) {
1561 /* We want the trie lookup to never result in unwildcarding
1562 * any bits that would not be unwildcarded otherwise.
1563 * Since the trie is shared by the whole classifier, it is
1564 * possible that the 'maskbits' contain bits that are
1565 * irrelevant for the partition relevant for the current
1566 * packet. Hence the checks below. */
1568 /* Check that the trie result will not unwildcard more bits
1569 * than this subtable would otherwise. */
1570 if (ctx->maskbits <= field_plen[j]) {
1571 /* Unwildcard the bits and skip the rest. */
1572 mask_set_prefix_bits(wc, ctx->be32ofs, ctx->maskbits);
1573 /* Note: Prerequisite already unwildcarded, as the only
1574 * prerequisite of the supported trie lookup fields is
1575 * the ethertype, which is always unwildcarded. */
1578 /* Can skip if the field is already unwildcarded. */
1579 if (mask_prefix_bits_set(wc, ctx->be32ofs, ctx->maskbits)) {
1588 /* Returns true if 'target' satisifies 'flow'/'mask', that is, if each bit
1589 * for which 'flow', for which 'mask' has a bit set, specifies a particular
1590 * value has the correct value in 'target'.
1592 * This function is equivalent to miniflow_equal_flow_in_minimask(flow,
1593 * target, mask) but this is faster because of the invariant that
1594 * flow->map and mask->masks.map are the same, and that this version
1595 * takes the 'wc'. */
1597 miniflow_and_mask_matches_flow(const struct miniflow *flow,
1598 const struct minimask *mask,
1599 const struct flow *target)
1601 const uint64_t *flowp = miniflow_get_values(flow);
1602 const uint64_t *maskp = miniflow_get_values(&mask->masks);
1603 const uint64_t *target_u64 = (const uint64_t *)target;
1606 FLOWMAP_FOR_EACH_MAP (map, mask->masks.map) {
1609 MAP_FOR_EACH_INDEX (idx, map) {
1610 if ((*flowp++ ^ target_u64[idx]) & *maskp++) {
1614 target_u64 += MAP_T_BITS;
1619 static inline const struct cls_match *
1620 find_match(const struct cls_subtable *subtable, cls_version_t version,
1621 const struct flow *flow, uint32_t hash)
1623 const struct cls_match *head, *rule;
1625 CMAP_FOR_EACH_WITH_HASH (head, cmap_node, hash, &subtable->rules) {
1626 if (OVS_LIKELY(miniflow_and_mask_matches_flow(&head->flow,
1629 /* Return highest priority rule that is visible. */
1630 CLS_MATCH_FOR_EACH (rule, head) {
1631 if (OVS_LIKELY(cls_match_visible_in_version(rule, version))) {
1641 static const struct cls_match *
1642 find_match_wc(const struct cls_subtable *subtable, cls_version_t version,
1643 const struct flow *flow, struct trie_ctx trie_ctx[CLS_MAX_TRIES],
1644 unsigned int n_tries, struct flow_wildcards *wc)
1646 if (OVS_UNLIKELY(!wc)) {
1647 return find_match(subtable, version, flow,
1648 flow_hash_in_minimask(flow, &subtable->mask, 0));
1651 uint32_t basis = 0, hash;
1652 const struct cls_match *rule = NULL;
1653 struct flowmap stages_map = FLOWMAP_EMPTY_INITIALIZER;
1654 unsigned int mask_offset = 0;
1657 /* Try to finish early by checking fields in segments. */
1658 for (i = 0; i < subtable->n_indices; i++) {
1659 if (check_tries(trie_ctx, n_tries, subtable->trie_plen,
1660 subtable->index_maps[i], flow, wc)) {
1661 /* 'wc' bits for the trie field set, now unwildcard the preceding
1662 * bits used so far. */
1666 /* Accumulate the map used so far. */
1667 stages_map = flowmap_or(stages_map, subtable->index_maps[i]);
1669 hash = flow_hash_in_minimask_range(flow, &subtable->mask,
1670 subtable->index_maps[i],
1671 &mask_offset, &basis);
1673 if (!ccmap_find(&subtable->indices[i], hash)) {
1677 /* Trie check for the final range. */
1678 if (check_tries(trie_ctx, n_tries, subtable->trie_plen,
1679 subtable->index_maps[i], flow, wc)) {
1682 hash = flow_hash_in_minimask_range(flow, &subtable->mask,
1683 subtable->index_maps[i],
1684 &mask_offset, &basis);
1685 rule = find_match(subtable, version, flow, hash);
1686 if (!rule && subtable->ports_mask_len) {
1687 /* The final stage had ports, but there was no match. Instead of
1688 * unwildcarding all the ports bits, use the ports trie to figure out a
1689 * smaller set of bits to unwildcard. */
1691 ovs_be32 value, plens, mask;
1693 mask = MINIFLOW_GET_BE32(&subtable->mask.masks, tp_src);
1694 value = ((OVS_FORCE ovs_be32 *)flow)[TP_PORTS_OFS32] & mask;
1695 mbits = trie_lookup_value(&subtable->ports_trie, &value, &plens, 32);
1697 ((OVS_FORCE ovs_be32 *)&wc->masks)[TP_PORTS_OFS32] |=
1698 mask & be32_prefix_mask(mbits);
1703 /* Must unwildcard all the fields, as they were looked at. */
1704 flow_wildcards_fold_minimask(wc, &subtable->mask);
1708 /* Unwildcard the bits in stages so far, as they were used in determining
1709 * there is no match. */
1710 flow_wildcards_fold_minimask_in_map(wc, &subtable->mask, stages_map);
1714 static struct cls_match *
1715 find_equal(const struct cls_subtable *subtable, const struct miniflow *flow,
1718 struct cls_match *head;
1720 CMAP_FOR_EACH_WITH_HASH (head, cmap_node, hash, &subtable->rules) {
1721 if (miniflow_equal(&head->flow, flow)) {
1728 /* A longest-prefix match tree. */
1730 /* Return at least 'plen' bits of the 'prefix', starting at bit offset 'ofs'.
1731 * Prefixes are in the network byte order, and the offset 0 corresponds to
1732 * the most significant bit of the first byte. The offset can be read as
1733 * "how many bits to skip from the start of the prefix starting at 'pr'". */
1735 raw_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
1739 pr += ofs / 32; /* Where to start. */
1740 ofs %= 32; /* How many bits to skip at 'pr'. */
1742 prefix = ntohl(*pr) << ofs; /* Get the first 32 - ofs bits. */
1743 if (plen > 32 - ofs) { /* Need more than we have already? */
1744 prefix |= ntohl(*++pr) >> (32 - ofs);
1746 /* Return with possible unwanted bits at the end. */
1750 /* Return min(TRIE_PREFIX_BITS, plen) bits of the 'prefix', starting at bit
1751 * offset 'ofs'. Prefixes are in the network byte order, and the offset 0
1752 * corresponds to the most significant bit of the first byte. The offset can
1753 * be read as "how many bits to skip from the start of the prefix starting at
1756 trie_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
1761 if (plen > TRIE_PREFIX_BITS) {
1762 plen = TRIE_PREFIX_BITS; /* Get at most TRIE_PREFIX_BITS. */
1764 /* Return with unwanted bits cleared. */
1765 return raw_get_prefix(pr, ofs, plen) & ~0u << (32 - plen);
1768 /* Return the number of equal bits in 'n_bits' of 'prefix's MSBs and a 'value'
1769 * starting at "MSB 0"-based offset 'ofs'. */
1771 prefix_equal_bits(uint32_t prefix, unsigned int n_bits, const ovs_be32 value[],
1774 uint64_t diff = prefix ^ raw_get_prefix(value, ofs, n_bits);
1775 /* Set the bit after the relevant bits to limit the result. */
1776 return raw_clz64(diff << 32 | UINT64_C(1) << (63 - n_bits));
1779 /* Return the number of equal bits in 'node' prefix and a 'prefix' of length
1780 * 'plen', starting at "MSB 0"-based offset 'ofs'. */
1782 trie_prefix_equal_bits(const struct trie_node *node, const ovs_be32 prefix[],
1783 unsigned int ofs, unsigned int plen)
1785 return prefix_equal_bits(node->prefix, MIN(node->n_bits, plen - ofs),
1789 /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' can
1790 * be greater than 31. */
1792 be_get_bit_at(const ovs_be32 value[], unsigned int ofs)
1794 return (((const uint8_t *)value)[ofs / 8] >> (7 - ofs % 8)) & 1u;
1797 /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' must
1798 * be between 0 and 31, inclusive. */
1800 get_bit_at(const uint32_t prefix, unsigned int ofs)
1802 return (prefix >> (31 - ofs)) & 1u;
1805 /* Create new branch. */
1806 static struct trie_node *
1807 trie_branch_create(const ovs_be32 *prefix, unsigned int ofs, unsigned int plen,
1808 unsigned int n_rules)
1810 struct trie_node *node = xmalloc(sizeof *node);
1812 node->prefix = trie_get_prefix(prefix, ofs, plen);
1814 if (plen <= TRIE_PREFIX_BITS) {
1815 node->n_bits = plen;
1816 ovsrcu_set_hidden(&node->edges[0], NULL);
1817 ovsrcu_set_hidden(&node->edges[1], NULL);
1818 node->n_rules = n_rules;
1819 } else { /* Need intermediate nodes. */
1820 struct trie_node *subnode = trie_branch_create(prefix,
1821 ofs + TRIE_PREFIX_BITS,
1822 plen - TRIE_PREFIX_BITS,
1824 int bit = get_bit_at(subnode->prefix, 0);
1825 node->n_bits = TRIE_PREFIX_BITS;
1826 ovsrcu_set_hidden(&node->edges[bit], subnode);
1827 ovsrcu_set_hidden(&node->edges[!bit], NULL);
1834 trie_node_destroy(const struct trie_node *node)
1836 ovsrcu_postpone(free, CONST_CAST(struct trie_node *, node));
1839 /* Copy a trie node for modification and postpone delete the old one. */
1840 static struct trie_node *
1841 trie_node_rcu_realloc(const struct trie_node *node)
1843 struct trie_node *new_node = xmalloc(sizeof *node);
1846 trie_node_destroy(node);
1852 trie_destroy(rcu_trie_ptr *trie)
1854 struct trie_node *node = ovsrcu_get_protected(struct trie_node *, trie);
1857 ovsrcu_set_hidden(trie, NULL);
1858 trie_destroy(&node->edges[0]);
1859 trie_destroy(&node->edges[1]);
1860 trie_node_destroy(node);
1865 trie_is_leaf(const struct trie_node *trie)
1868 return !ovsrcu_get(struct trie_node *, &trie->edges[0])
1869 && !ovsrcu_get(struct trie_node *, &trie->edges[1]);
1873 mask_set_prefix_bits(struct flow_wildcards *wc, uint8_t be32ofs,
1874 unsigned int n_bits)
1876 ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
1879 for (i = 0; i < n_bits / 32; i++) {
1880 mask[i] = OVS_BE32_MAX;
1883 mask[i] |= htonl(~0u << (32 - n_bits % 32));
1888 mask_prefix_bits_set(const struct flow_wildcards *wc, uint8_t be32ofs,
1889 unsigned int n_bits)
1891 ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
1893 ovs_be32 zeroes = 0;
1895 for (i = 0; i < n_bits / 32; i++) {
1899 zeroes |= ~mask[i] & htonl(~0u << (32 - n_bits % 32));
1902 return !zeroes; /* All 'n_bits' bits set. */
1905 static rcu_trie_ptr *
1906 trie_next_edge(struct trie_node *node, const ovs_be32 value[],
1909 return node->edges + be_get_bit_at(value, ofs);
1912 static const struct trie_node *
1913 trie_next_node(const struct trie_node *node, const ovs_be32 value[],
1916 return ovsrcu_get(struct trie_node *,
1917 &node->edges[be_get_bit_at(value, ofs)]);
1920 /* Set the bit at ("MSB 0"-based) offset 'ofs'. 'ofs' can be greater than 31.
1923 be_set_bit_at(ovs_be32 value[], unsigned int ofs)
1925 ((uint8_t *)value)[ofs / 8] |= 1u << (7 - ofs % 8);
1928 /* Returns the number of bits in the prefix mask necessary to determine a
1929 * mismatch, in case there are longer prefixes in the tree below the one that
1931 * '*plens' will have a bit set for each prefix length that may have matching
1932 * rules. The caller is responsible for clearing the '*plens' prior to
1936 trie_lookup_value(const rcu_trie_ptr *trie, const ovs_be32 value[],
1937 ovs_be32 plens[], unsigned int n_bits)
1939 const struct trie_node *prev = NULL;
1940 const struct trie_node *node = ovsrcu_get(struct trie_node *, trie);
1941 unsigned int match_len = 0; /* Number of matching bits. */
1943 for (; node; prev = node, node = trie_next_node(node, value, match_len)) {
1944 unsigned int eqbits;
1945 /* Check if this edge can be followed. */
1946 eqbits = prefix_equal_bits(node->prefix, node->n_bits, value,
1948 match_len += eqbits;
1949 if (eqbits < node->n_bits) { /* Mismatch, nothing more to be found. */
1950 /* Bit at offset 'match_len' differed. */
1951 return match_len + 1; /* Includes the first mismatching bit. */
1953 /* Full match, check if rules exist at this prefix length. */
1954 if (node->n_rules > 0) {
1955 be_set_bit_at(plens, match_len - 1);
1957 if (match_len >= n_bits) {
1958 return n_bits; /* Full prefix. */
1961 /* node == NULL. Full match so far, but we tried to follow an
1962 * non-existing branch. Need to exclude the other branch if it exists
1963 * (it does not if we were called on an empty trie or 'prev' is a leaf
1965 return !prev || trie_is_leaf(prev) ? match_len : match_len + 1;
1969 trie_lookup(const struct cls_trie *trie, const struct flow *flow,
1970 union trie_prefix *plens)
1972 const struct mf_field *mf = trie->field;
1974 /* Check that current flow matches the prerequisites for the trie
1975 * field. Some match fields are used for multiple purposes, so we
1976 * must check that the trie is relevant for this flow. */
1977 if (mf_are_prereqs_ok(mf, flow)) {
1978 return trie_lookup_value(&trie->root,
1979 &((ovs_be32 *)flow)[mf->flow_be32ofs],
1980 &plens->be32, mf->n_bits);
1982 memset(plens, 0xff, sizeof *plens); /* All prefixes, no skipping. */
1983 return 0; /* Value not used in this case. */
1986 /* Returns the length of a prefix match mask for the field 'mf' in 'minimask'.
1987 * Returns the u32 offset to the miniflow data in '*miniflow_index', if
1988 * 'miniflow_index' is not NULL. */
1990 minimask_get_prefix_len(const struct minimask *minimask,
1991 const struct mf_field *mf)
1993 unsigned int n_bits = 0, mask_tz = 0; /* Non-zero when end of mask seen. */
1994 uint8_t be32_ofs = mf->flow_be32ofs;
1995 uint8_t be32_end = be32_ofs + mf->n_bytes / 4;
1997 for (; be32_ofs < be32_end; ++be32_ofs) {
1998 uint32_t mask = ntohl(minimask_get_be32(minimask, be32_ofs));
2000 /* Validate mask, count the mask length. */
2003 return 0; /* No bits allowed after mask ended. */
2006 if (~mask & (~mask + 1)) {
2007 return 0; /* Mask not contiguous. */
2009 mask_tz = ctz32(mask);
2010 n_bits += 32 - mask_tz;
2018 * This is called only when mask prefix is known to be CIDR and non-zero.
2019 * Relies on the fact that the flow and mask have the same map, and since
2020 * the mask is CIDR, the storage for the flow field exists even if it
2021 * happened to be zeros.
2023 static const ovs_be32 *
2024 minimatch_get_prefix(const struct minimatch *match, const struct mf_field *mf)
2026 size_t u64_ofs = mf->flow_be32ofs / 2;
2028 return (OVS_FORCE const ovs_be32 *)miniflow_get__(match->flow, u64_ofs)
2029 + (mf->flow_be32ofs & 1);
2032 /* Insert rule in to the prefix tree.
2033 * 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2036 trie_insert(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
2038 trie_insert_prefix(&trie->root,
2039 minimatch_get_prefix(&rule->match, trie->field), mlen);
2043 trie_insert_prefix(rcu_trie_ptr *edge, const ovs_be32 *prefix, int mlen)
2045 struct trie_node *node;
2048 /* Walk the tree. */
2049 for (; (node = ovsrcu_get_protected(struct trie_node *, edge));
2050 edge = trie_next_edge(node, prefix, ofs)) {
2051 unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
2053 if (eqbits < node->n_bits) {
2054 /* Mismatch, new node needs to be inserted above. */
2055 int old_branch = get_bit_at(node->prefix, eqbits);
2056 struct trie_node *new_parent;
2058 new_parent = trie_branch_create(prefix, ofs - eqbits, eqbits,
2059 ofs == mlen ? 1 : 0);
2060 /* Copy the node to modify it. */
2061 node = trie_node_rcu_realloc(node);
2062 /* Adjust the new node for its new position in the tree. */
2063 node->prefix <<= eqbits;
2064 node->n_bits -= eqbits;
2065 ovsrcu_set_hidden(&new_parent->edges[old_branch], node);
2067 /* Check if need a new branch for the new rule. */
2069 ovsrcu_set_hidden(&new_parent->edges[!old_branch],
2070 trie_branch_create(prefix, ofs, mlen - ofs,
2073 ovsrcu_set(edge, new_parent); /* Publish changes. */
2076 /* Full match so far. */
2079 /* Full match at the current node, rule needs to be added here. */
2084 /* Must insert a new tree branch for the new rule. */
2085 ovsrcu_set(edge, trie_branch_create(prefix, ofs, mlen - ofs, 1));
2088 /* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2091 trie_remove(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
2093 trie_remove_prefix(&trie->root,
2094 minimatch_get_prefix(&rule->match, trie->field), mlen);
2097 /* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2100 trie_remove_prefix(rcu_trie_ptr *root, const ovs_be32 *prefix, int mlen)
2102 struct trie_node *node;
2103 rcu_trie_ptr *edges[sizeof(union trie_prefix) * CHAR_BIT];
2104 int depth = 0, ofs = 0;
2106 /* Walk the tree. */
2107 for (edges[0] = root;
2108 (node = ovsrcu_get_protected(struct trie_node *, edges[depth]));
2109 edges[++depth] = trie_next_edge(node, prefix, ofs)) {
2110 unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
2112 if (eqbits < node->n_bits) {
2113 /* Mismatch, nothing to be removed. This should never happen, as
2114 * only rules in the classifier are ever removed. */
2115 break; /* Log a warning. */
2117 /* Full match so far. */
2121 /* Full prefix match at the current node, remove rule here. */
2122 if (!node->n_rules) {
2123 break; /* Log a warning. */
2127 /* Check if can prune the tree. */
2128 while (!node->n_rules) {
2129 struct trie_node *next,
2130 *edge0 = ovsrcu_get_protected(struct trie_node *,
2132 *edge1 = ovsrcu_get_protected(struct trie_node *,
2135 if (edge0 && edge1) {
2136 break; /* A branching point, cannot prune. */
2139 /* Else have at most one child node, remove this node. */
2140 next = edge0 ? edge0 : edge1;
2143 if (node->n_bits + next->n_bits > TRIE_PREFIX_BITS) {
2144 break; /* Cannot combine. */
2146 next = trie_node_rcu_realloc(next); /* Modify. */
2148 /* Combine node with next. */
2149 next->prefix = node->prefix | next->prefix >> node->n_bits;
2150 next->n_bits += node->n_bits;
2152 /* Update the parent's edge. */
2153 ovsrcu_set(edges[depth], next); /* Publish changes. */
2154 trie_node_destroy(node);
2156 if (next || !depth) {
2157 /* Branch not pruned or at root, nothing more to do. */
2160 node = ovsrcu_get_protected(struct trie_node *,
2166 /* Cannot go deeper. This should never happen, since only rules
2167 * that actually exist in the classifier are ever removed. */
2171 #define CLS_MATCH_POISON (struct cls_match *)(UINTPTR_MAX / 0xf * 0xb)
2174 cls_match_free_cb(struct cls_match *rule)
2176 ovsrcu_set_hidden(&rule->next, CLS_MATCH_POISON);