2 * Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014 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"
20 #include <netinet/in.h>
21 #include "byte-order.h"
22 #include "dynamic-string.h"
34 VLOG_DEFINE_THIS_MODULE(classifier);
38 /* Ports trie depends on both ports sharing the same ovs_be32. */
39 #define TP_PORTS_OFS32 (offsetof(struct flow, tp_src) / 4)
40 BUILD_ASSERT_DECL(TP_PORTS_OFS32 == offsetof(struct flow, tp_dst) / 4);
42 /* A set of rules that all have the same fields wildcarded. */
44 /* The fields are only used by writers and iterators. */
45 struct cmap_node cmap_node; /* Within struct classifier 'subtables_map'. */
47 /* The fields are only used by writers. */
48 int n_rules OVS_GUARDED; /* Number of rules, including
50 unsigned int max_priority OVS_GUARDED; /* Max priority of any rule in
52 unsigned int max_count OVS_GUARDED; /* Count of max_priority rules. */
54 /* These fields are accessed by readers who care about wildcarding. */
55 tag_type tag; /* Tag generated from mask for partitioning (const). */
56 uint8_t n_indices; /* How many indices to use (const). */
57 uint8_t index_ofs[CLS_MAX_INDICES]; /* u32 segment boundaries (const). */
58 unsigned int trie_plen[CLS_MAX_TRIES]; /* Trie prefix length in 'mask'
59 * (runtime configurable). */
60 int ports_mask_len; /* (const) */
61 struct cmap indices[CLS_MAX_INDICES]; /* Staged lookup indices. */
62 rcu_trie_ptr ports_trie; /* NULL if none. */
64 /* These fields are accessed by all readers. */
65 struct cmap rules; /* Contains "struct cls_rule"s. */
66 struct minimask mask; /* Wildcards for fields (const). */
67 /* 'mask' must be the last field. */
70 /* Associates a metadata value (that is, a value of the OpenFlow 1.1+ metadata
71 * field) with tags for the "cls_subtable"s that contain rules that match that
73 struct cls_partition {
74 struct cmap_node cmap_node; /* In struct classifier's 'partitions' map. */
75 ovs_be64 metadata; /* metadata value for this partition. */
76 tag_type tags; /* OR of each flow's cls_subtable tag. */
77 struct tag_tracker tracker OVS_GUARDED; /* Tracks the bits in 'tags'. */
80 /* Internal representation of a rule in a "struct cls_subtable". */
82 /* Accessed only by writers and iterators. */
83 struct list list OVS_GUARDED; /* List of identical, lower-priority rules. */
85 /* Accessed only by writers. */
86 struct cls_partition *partition OVS_GUARDED;
88 /* Accessed by readers interested in wildcarding. */
89 unsigned int priority; /* Larger numbers are higher priorities. */
90 struct cmap_node index_nodes[CLS_MAX_INDICES]; /* Within subtable's
92 /* Accessed by all readers. */
93 struct cmap_node cmap_node; /* Within struct cls_subtable 'rules'. */
94 struct cls_rule *cls_rule;
95 struct miniflow flow; /* Matching rule. Mask is in the subtable. */
96 /* 'flow' must be the last field. */
99 static struct cls_match *
100 cls_match_alloc(struct cls_rule *rule)
102 int count = count_1bits(rule->match.flow.map);
104 struct cls_match *cls_match
105 = xmalloc(sizeof *cls_match - sizeof cls_match->flow.inline_values
106 + MINIFLOW_VALUES_SIZE(count));
108 cls_match->cls_rule = rule;
109 miniflow_clone_inline(&cls_match->flow, &rule->match.flow, count);
110 cls_match->priority = rule->priority;
111 rule->cls_match = cls_match;
116 static struct cls_subtable *find_subtable(const struct classifier *cls,
117 const struct minimask *)
118 OVS_REQUIRES(cls->mutex);
119 static struct cls_subtable *insert_subtable(struct classifier *cls,
120 const struct minimask *)
121 OVS_REQUIRES(cls->mutex);
122 static void destroy_subtable(struct classifier *cls, struct cls_subtable *)
123 OVS_REQUIRES(cls->mutex);
124 static struct cls_match *insert_rule(struct classifier *cls,
125 struct cls_subtable *, struct cls_rule *)
126 OVS_REQUIRES(cls->mutex);
128 static struct cls_match *find_match_wc(const struct cls_subtable *,
129 const struct flow *, struct trie_ctx *,
130 unsigned int n_tries,
131 struct flow_wildcards *);
132 static struct cls_match *find_equal(struct cls_subtable *,
133 const struct miniflow *, uint32_t hash);
135 /* Iterates RULE over HEAD and all of the cls_rules on HEAD->list.
136 * Classifier's mutex must be held while iterating, as the list is
137 * protoceted by it. */
138 #define FOR_EACH_RULE_IN_LIST(RULE, HEAD) \
139 for ((RULE) = (HEAD); (RULE) != NULL; (RULE) = next_rule_in_list(RULE))
140 #define FOR_EACH_RULE_IN_LIST_SAFE(RULE, NEXT, HEAD) \
141 for ((RULE) = (HEAD); \
142 (RULE) != NULL && ((NEXT) = next_rule_in_list(RULE), true); \
145 static struct cls_match *next_rule_in_list__(struct cls_match *);
146 static struct cls_match *next_rule_in_list(struct cls_match *);
148 static unsigned int minimask_get_prefix_len(const struct minimask *,
149 const struct mf_field *);
150 static void trie_init(struct classifier *cls, int trie_idx,
151 const struct mf_field *)
152 OVS_REQUIRES(cls->mutex);
153 static unsigned int trie_lookup(const struct cls_trie *, const struct flow *,
154 union mf_value *plens);
155 static unsigned int trie_lookup_value(const rcu_trie_ptr *,
156 const ovs_be32 value[], ovs_be32 plens[],
157 unsigned int value_bits);
158 static void trie_destroy(rcu_trie_ptr *);
159 static void trie_insert(struct cls_trie *, const struct cls_rule *, int mlen);
160 static void trie_insert_prefix(rcu_trie_ptr *, const ovs_be32 *prefix,
162 static void trie_remove(struct cls_trie *, const struct cls_rule *, int mlen);
163 static void trie_remove_prefix(rcu_trie_ptr *, const ovs_be32 *prefix,
165 static void mask_set_prefix_bits(struct flow_wildcards *, uint8_t be32ofs,
166 unsigned int n_bits);
167 static bool mask_prefix_bits_set(const struct flow_wildcards *,
168 uint8_t be32ofs, unsigned int n_bits);
170 /* flow/miniflow/minimask/minimatch utilities.
171 * These are only used by the classifier, so place them here to allow
172 * for better optimization. */
174 static inline uint64_t
175 miniflow_get_map_in_range(const struct miniflow *miniflow,
176 uint8_t start, uint8_t end, unsigned int *offset)
178 uint64_t map = miniflow->map;
182 uint64_t msk = (UINT64_C(1) << start) - 1; /* 'start' LSBs set */
183 *offset = count_1bits(map & msk);
186 if (end < FLOW_U32S) {
187 uint64_t msk = (UINT64_C(1) << end) - 1; /* 'end' LSBs set */
193 /* Returns a hash value for the bits of 'flow' where there are 1-bits in
194 * 'mask', given 'basis'.
196 * The hash values returned by this function are the same as those returned by
197 * miniflow_hash_in_minimask(), only the form of the arguments differ. */
198 static inline uint32_t
199 flow_hash_in_minimask(const struct flow *flow, const struct minimask *mask,
202 const uint32_t *mask_values = miniflow_get_u32_values(&mask->masks);
203 const uint32_t *flow_u32 = (const uint32_t *)flow;
204 const uint32_t *p = mask_values;
209 for (map = mask->masks.map; map; map = zero_rightmost_1bit(map)) {
210 hash = hash_add(hash, flow_u32[raw_ctz(map)] & *p++);
213 return hash_finish(hash, (p - mask_values) * 4);
216 /* Returns a hash value for the bits of 'flow' where there are 1-bits in
217 * 'mask', given 'basis'.
219 * The hash values returned by this function are the same as those returned by
220 * flow_hash_in_minimask(), only the form of the arguments differ. */
221 static inline uint32_t
222 miniflow_hash_in_minimask(const struct miniflow *flow,
223 const struct minimask *mask, uint32_t basis)
225 const uint32_t *mask_values = miniflow_get_u32_values(&mask->masks);
226 const uint32_t *p = mask_values;
227 uint32_t hash = basis;
230 MINIFLOW_FOR_EACH_IN_MAP(flow_u32, flow, mask->masks.map) {
231 hash = hash_add(hash, flow_u32 & *p++);
234 return hash_finish(hash, (p - mask_values) * 4);
237 /* Returns a hash value for the bits of range [start, end) in 'flow',
238 * where there are 1-bits in 'mask', given 'hash'.
240 * The hash values returned by this function are the same as those returned by
241 * minimatch_hash_range(), only the form of the arguments differ. */
242 static inline uint32_t
243 flow_hash_in_minimask_range(const struct flow *flow,
244 const struct minimask *mask,
245 uint8_t start, uint8_t end, uint32_t *basis)
247 const uint32_t *mask_values = miniflow_get_u32_values(&mask->masks);
248 const uint32_t *flow_u32 = (const uint32_t *)flow;
250 uint64_t map = miniflow_get_map_in_range(&mask->masks, start, end,
252 const uint32_t *p = mask_values + offset;
253 uint32_t hash = *basis;
255 for (; map; map = zero_rightmost_1bit(map)) {
256 hash = hash_add(hash, flow_u32[raw_ctz(map)] & *p++);
259 *basis = hash; /* Allow continuation from the unfinished value. */
260 return hash_finish(hash, (p - mask_values) * 4);
263 /* Fold minimask 'mask''s wildcard mask into 'wc's wildcard mask. */
265 flow_wildcards_fold_minimask(struct flow_wildcards *wc,
266 const struct minimask *mask)
268 flow_union_with_miniflow(&wc->masks, &mask->masks);
271 /* Fold minimask 'mask''s wildcard mask into 'wc's wildcard mask
272 * in range [start, end). */
274 flow_wildcards_fold_minimask_range(struct flow_wildcards *wc,
275 const struct minimask *mask,
276 uint8_t start, uint8_t end)
278 uint32_t *dst_u32 = (uint32_t *)&wc->masks;
280 uint64_t map = miniflow_get_map_in_range(&mask->masks, start, end,
282 const uint32_t *p = miniflow_get_u32_values(&mask->masks) + offset;
284 for (; map; map = zero_rightmost_1bit(map)) {
285 dst_u32[raw_ctz(map)] |= *p++;
289 /* Returns a hash value for 'flow', given 'basis'. */
290 static inline uint32_t
291 miniflow_hash(const struct miniflow *flow, uint32_t basis)
293 const uint32_t *values = miniflow_get_u32_values(flow);
294 const uint32_t *p = values;
295 uint32_t hash = basis;
296 uint64_t hash_map = 0;
299 for (map = flow->map; map; map = zero_rightmost_1bit(map)) {
301 hash = hash_add(hash, *p);
302 hash_map |= rightmost_1bit(map);
306 hash = hash_add(hash, hash_map);
307 hash = hash_add(hash, hash_map >> 32);
309 return hash_finish(hash, p - values);
312 /* Returns a hash value for 'mask', given 'basis'. */
313 static inline uint32_t
314 minimask_hash(const struct minimask *mask, uint32_t basis)
316 return miniflow_hash(&mask->masks, basis);
319 /* Returns a hash value for 'match', given 'basis'. */
320 static inline uint32_t
321 minimatch_hash(const struct minimatch *match, uint32_t basis)
323 return miniflow_hash(&match->flow, minimask_hash(&match->mask, basis));
326 /* Returns a hash value for the bits of range [start, end) in 'minimatch',
329 * The hash values returned by this function are the same as those returned by
330 * flow_hash_in_minimask_range(), only the form of the arguments differ. */
331 static inline uint32_t
332 minimatch_hash_range(const struct minimatch *match, uint8_t start, uint8_t end,
336 const uint32_t *p, *q;
337 uint32_t hash = *basis;
340 n = count_1bits(miniflow_get_map_in_range(&match->mask.masks, start, end,
342 q = miniflow_get_u32_values(&match->mask.masks) + offset;
343 p = miniflow_get_u32_values(&match->flow) + offset;
345 for (i = 0; i < n; i++) {
346 hash = hash_add(hash, p[i] & q[i]);
348 *basis = hash; /* Allow continuation from the unfinished value. */
349 return hash_finish(hash, (offset + n) * 4);
355 /* Initializes 'rule' to match packets specified by 'match' at the given
356 * 'priority'. 'match' must satisfy the invariant described in the comment at
357 * the definition of struct match.
359 * The caller must eventually destroy 'rule' with cls_rule_destroy().
361 * (OpenFlow uses priorities between 0 and UINT16_MAX, inclusive, but
362 * internally Open vSwitch supports a wider range.) */
364 cls_rule_init(struct cls_rule *rule,
365 const struct match *match, unsigned int priority)
367 minimatch_init(&rule->match, match);
368 rule->priority = priority;
369 rule->cls_match = NULL;
372 /* Same as cls_rule_init() for initialization from a "struct minimatch". */
374 cls_rule_init_from_minimatch(struct cls_rule *rule,
375 const struct minimatch *match,
376 unsigned int priority)
378 minimatch_clone(&rule->match, match);
379 rule->priority = priority;
380 rule->cls_match = NULL;
383 /* Initializes 'dst' as a copy of 'src'.
385 * The caller must eventually destroy 'dst' with cls_rule_destroy(). */
387 cls_rule_clone(struct cls_rule *dst, const struct cls_rule *src)
389 minimatch_clone(&dst->match, &src->match);
390 dst->priority = src->priority;
391 dst->cls_match = NULL;
394 /* Initializes 'dst' with the data in 'src', destroying 'src'.
396 * The caller must eventually destroy 'dst' with cls_rule_destroy(). */
398 cls_rule_move(struct cls_rule *dst, struct cls_rule *src)
400 minimatch_move(&dst->match, &src->match);
401 dst->priority = src->priority;
402 dst->cls_match = NULL;
405 /* Frees memory referenced by 'rule'. Doesn't free 'rule' itself (it's
406 * normally embedded into a larger structure).
408 * ('rule' must not currently be in a classifier.) */
410 cls_rule_destroy(struct cls_rule *rule)
412 ovs_assert(!rule->cls_match);
413 minimatch_destroy(&rule->match);
416 /* Returns true if 'a' and 'b' match the same packets at the same priority,
417 * false if they differ in some way. */
419 cls_rule_equal(const struct cls_rule *a, const struct cls_rule *b)
421 return a->priority == b->priority && minimatch_equal(&a->match, &b->match);
424 /* Returns a hash value for 'rule', folding in 'basis'. */
426 cls_rule_hash(const struct cls_rule *rule, uint32_t basis)
428 return minimatch_hash(&rule->match, hash_int(rule->priority, basis));
431 /* Appends a string describing 'rule' to 's'. */
433 cls_rule_format(const struct cls_rule *rule, struct ds *s)
435 minimatch_format(&rule->match, s, rule->priority);
438 /* Returns true if 'rule' matches every packet, false otherwise. */
440 cls_rule_is_catchall(const struct cls_rule *rule)
442 return minimask_is_catchall(&rule->match.mask);
445 /* Initializes 'cls' as a classifier that initially contains no classification
448 classifier_init(struct classifier *cls, const uint8_t *flow_segments)
449 OVS_EXCLUDED(cls->mutex)
451 ovs_mutex_init(&cls->mutex);
452 ovs_mutex_lock(&cls->mutex);
454 cmap_init(&cls->subtables_map);
455 pvector_init(&cls->subtables);
456 cmap_init(&cls->partitions);
457 cls->n_flow_segments = 0;
459 while (cls->n_flow_segments < CLS_MAX_INDICES
460 && *flow_segments < FLOW_U32S) {
461 cls->flow_segments[cls->n_flow_segments++] = *flow_segments++;
465 for (int i = 0; i < CLS_MAX_TRIES; i++) {
466 trie_init(cls, i, NULL);
468 ovs_mutex_unlock(&cls->mutex);
471 /* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
472 * caller's responsibility.
473 * May only be called after all the readers have been terminated. */
475 classifier_destroy(struct classifier *cls)
476 OVS_EXCLUDED(cls->mutex)
479 struct cls_partition *partition;
480 struct cls_subtable *subtable;
483 ovs_mutex_lock(&cls->mutex);
484 for (i = 0; i < cls->n_tries; i++) {
485 trie_destroy(&cls->tries[i].root);
488 CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
489 destroy_subtable(cls, subtable);
491 cmap_destroy(&cls->subtables_map);
493 CMAP_FOR_EACH (partition, cmap_node, &cls->partitions) {
494 ovsrcu_postpone(free, partition);
496 cmap_destroy(&cls->partitions);
498 pvector_destroy(&cls->subtables);
499 ovs_mutex_unlock(&cls->mutex);
500 ovs_mutex_destroy(&cls->mutex);
504 /* Set the fields for which prefix lookup should be performed. */
506 classifier_set_prefix_fields(struct classifier *cls,
507 const enum mf_field_id *trie_fields,
508 unsigned int n_fields)
509 OVS_EXCLUDED(cls->mutex)
511 const struct mf_field * new_fields[CLS_MAX_TRIES];
512 struct mf_bitmap fields = MF_BITMAP_INITIALIZER;
514 bool changed = false;
516 ovs_mutex_lock(&cls->mutex);
517 for (i = 0; i < n_fields && n_tries < CLS_MAX_TRIES; i++) {
518 const struct mf_field *field = mf_from_id(trie_fields[i]);
519 if (field->flow_be32ofs < 0 || field->n_bits % 32) {
520 /* Incompatible field. This is the only place where we
521 * enforce these requirements, but the rest of the trie code
522 * depends on the flow_be32ofs to be non-negative and the
523 * field length to be a multiple of 32 bits. */
527 if (bitmap_is_set(fields.bm, trie_fields[i])) {
528 /* Duplicate field, there is no need to build more than
529 * one index for any one field. */
532 bitmap_set1(fields.bm, trie_fields[i]);
534 new_fields[n_tries] = NULL;
535 if (n_tries >= cls->n_tries || field != cls->tries[n_tries].field) {
536 new_fields[n_tries] = field;
542 if (changed || n_tries < cls->n_tries) {
543 struct cls_subtable *subtable;
545 /* Trie configuration needs to change. Disable trie lookups
546 * for the tries that are changing and wait all the current readers
547 * with the old configuration to be done. */
549 CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
550 for (i = 0; i < cls->n_tries; i++) {
551 if ((i < n_tries && new_fields[i]) || i >= n_tries) {
552 if (subtable->trie_plen[i]) {
553 subtable->trie_plen[i] = 0;
559 /* Synchronize if any readers were using tries. The readers may
560 * temporarily function without the trie lookup based optimizations. */
562 /* ovsrcu_synchronize() functions as a memory barrier, so it does
563 * not matter that subtable->trie_plen is not atomic. */
564 ovsrcu_synchronize();
567 /* Now set up the tries. */
568 for (i = 0; i < n_tries; i++) {
570 trie_init(cls, i, new_fields[i]);
573 /* Destroy the rest, if any. */
574 for (; i < cls->n_tries; i++) {
575 trie_init(cls, i, NULL);
578 cls->n_tries = n_tries;
579 ovs_mutex_unlock(&cls->mutex);
583 ovs_mutex_unlock(&cls->mutex);
584 return false; /* No change. */
588 trie_init(struct classifier *cls, int trie_idx, const struct mf_field *field)
589 OVS_REQUIRES(cls->mutex)
591 struct cls_trie *trie = &cls->tries[trie_idx];
592 struct cls_subtable *subtable;
594 if (trie_idx < cls->n_tries) {
595 trie_destroy(&trie->root);
597 ovsrcu_set_hidden(&trie->root, NULL);
601 /* Add existing rules to the new trie. */
602 CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
605 plen = field ? minimask_get_prefix_len(&subtable->mask, field) : 0;
607 struct cls_match *head;
609 CMAP_FOR_EACH (head, cmap_node, &subtable->rules) {
610 struct cls_match *match;
612 FOR_EACH_RULE_IN_LIST (match, head) {
613 trie_insert(trie, match->cls_rule, plen);
617 /* Initialize subtable's prefix length on this field. This will
618 * allow readers to use the trie. */
619 atomic_thread_fence(memory_order_release);
620 subtable->trie_plen[trie_idx] = plen;
624 /* Returns true if 'cls' contains no classification rules, false otherwise.
625 * Checking the cmap requires no locking. */
627 classifier_is_empty(const struct classifier *cls)
629 return cmap_is_empty(&cls->subtables_map);
632 /* Returns the number of rules in 'cls'. */
634 classifier_count(const struct classifier *cls)
635 OVS_NO_THREAD_SAFETY_ANALYSIS
637 /* n_rules is an int, so in the presence of concurrent writers this will
638 * return either the old or a new value. */
643 hash_metadata(ovs_be64 metadata_)
645 uint64_t metadata = (OVS_FORCE uint64_t) metadata_;
646 return hash_uint64(metadata);
649 static struct cls_partition *
650 find_partition(const struct classifier *cls, ovs_be64 metadata, uint32_t hash)
652 struct cls_partition *partition;
654 CMAP_FOR_EACH_WITH_HASH (partition, cmap_node, hash, &cls->partitions) {
655 if (partition->metadata == metadata) {
663 static struct cls_partition *
664 create_partition(struct classifier *cls, struct cls_subtable *subtable,
666 OVS_REQUIRES(cls->mutex)
668 uint32_t hash = hash_metadata(metadata);
669 struct cls_partition *partition = find_partition(cls, metadata, hash);
671 partition = xmalloc(sizeof *partition);
672 partition->metadata = metadata;
674 tag_tracker_init(&partition->tracker);
675 cmap_insert(&cls->partitions, &partition->cmap_node, hash);
677 tag_tracker_add(&partition->tracker, &partition->tags, subtable->tag);
681 static inline ovs_be32 minimatch_get_ports(const struct minimatch *match)
683 /* Could optimize to use the same map if needed for fast path. */
684 return MINIFLOW_GET_BE32(&match->flow, tp_src)
685 & MINIFLOW_GET_BE32(&match->mask.masks, tp_src);
688 /* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller
689 * must not modify or free it.
691 * If 'cls' already contains an identical rule (including wildcards, values of
692 * fixed fields, and priority), replaces the old rule by 'rule' and returns the
693 * rule that was replaced. The caller takes ownership of the returned rule and
694 * is thus responsible for destroying it with cls_rule_destroy(), freeing the
695 * memory block in which it resides, etc., as necessary.
697 * Returns NULL if 'cls' does not contain a rule with an identical key, after
698 * inserting the new rule. In this case, no rules are displaced by the new
699 * rule, even rules that cannot have any effect because the new rule matches a
700 * superset of their flows and has higher priority. */
702 classifier_replace(struct classifier *cls, struct cls_rule *rule)
703 OVS_EXCLUDED(cls->mutex)
705 struct cls_match *old_rule;
706 struct cls_subtable *subtable;
707 struct cls_rule *old_cls_rule = NULL;
709 ovs_mutex_lock(&cls->mutex);
710 subtable = find_subtable(cls, &rule->match.mask);
712 subtable = insert_subtable(cls, &rule->match.mask);
715 old_rule = insert_rule(cls, subtable, rule);
719 rule->cls_match->partition = NULL;
720 if (minimask_get_metadata_mask(&rule->match.mask) == OVS_BE64_MAX) {
721 ovs_be64 metadata = miniflow_get_metadata(&rule->match.flow);
722 rule->cls_match->partition = create_partition(cls, subtable,
728 for (int i = 0; i < cls->n_tries; i++) {
729 if (subtable->trie_plen[i]) {
730 trie_insert(&cls->tries[i], rule, subtable->trie_plen[i]);
735 if (subtable->ports_mask_len) {
736 /* We mask the value to be inserted to always have the wildcarded
737 * bits in known (zero) state, so we can include them in comparison
738 * and they will always match (== their original value does not
740 ovs_be32 masked_ports = minimatch_get_ports(&rule->match);
742 trie_insert_prefix(&subtable->ports_trie, &masked_ports,
743 subtable->ports_mask_len);
746 old_cls_rule = old_rule->cls_rule;
747 rule->cls_match->partition = old_rule->partition;
748 old_cls_rule->cls_match = NULL;
750 /* 'old_rule' contains a cmap_node, which may not be freed
752 ovsrcu_postpone(free, old_rule);
754 ovs_mutex_unlock(&cls->mutex);
758 /* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller
759 * must not modify or free it.
761 * 'cls' must not contain an identical rule (including wildcards, values of
762 * fixed fields, and priority). Use classifier_find_rule_exactly() to find
765 classifier_insert(struct classifier *cls, struct cls_rule *rule)
767 struct cls_rule *displaced_rule = classifier_replace(cls, rule);
768 ovs_assert(!displaced_rule);
771 /* Removes 'rule' from 'cls'. It is the caller's responsibility to destroy
772 * 'rule' with cls_rule_destroy(), freeing the memory block in which 'rule'
773 * resides, etc., as necessary. */
775 classifier_remove(struct classifier *cls, struct cls_rule *rule)
776 OVS_EXCLUDED(cls->mutex)
778 struct cls_partition *partition;
779 struct cls_match *cls_match = rule->cls_match;
780 struct cls_match *head;
781 struct cls_subtable *subtable;
783 uint32_t basis = 0, hash, ihash[CLS_MAX_INDICES];
784 uint8_t prev_be32ofs = 0;
786 ovs_assert(cls_match);
788 ovs_mutex_lock(&cls->mutex);
789 subtable = find_subtable(cls, &rule->match.mask);
790 ovs_assert(subtable);
792 if (subtable->ports_mask_len) {
793 ovs_be32 masked_ports = minimatch_get_ports(&rule->match);
795 trie_remove_prefix(&subtable->ports_trie,
796 &masked_ports, subtable->ports_mask_len);
798 for (i = 0; i < cls->n_tries; i++) {
799 if (subtable->trie_plen[i]) {
800 trie_remove(&cls->tries[i], rule, subtable->trie_plen[i]);
804 /* Remove rule node from indices. */
805 for (i = 0; i < subtable->n_indices; i++) {
806 ihash[i] = minimatch_hash_range(&rule->match, prev_be32ofs,
807 subtable->index_ofs[i], &basis);
808 cmap_remove(&subtable->indices[i], &cls_match->index_nodes[i],
810 prev_be32ofs = subtable->index_ofs[i];
812 hash = minimatch_hash_range(&rule->match, prev_be32ofs, FLOW_U32S, &basis);
814 head = find_equal(subtable, &rule->match.flow, hash);
815 if (head != cls_match) {
816 list_remove(&cls_match->list);
817 } else if (list_is_empty(&cls_match->list)) {
818 cmap_remove(&subtable->rules, &cls_match->cmap_node, hash);
820 struct cls_match *next = CONTAINER_OF(cls_match->list.next,
821 struct cls_match, list);
823 list_remove(&cls_match->list);
824 cmap_replace(&subtable->rules, &cls_match->cmap_node,
825 &next->cmap_node, hash);
828 partition = cls_match->partition;
830 tag_tracker_subtract(&partition->tracker, &partition->tags,
832 if (!partition->tags) {
833 cmap_remove(&cls->partitions, &partition->cmap_node,
834 hash_metadata(partition->metadata));
835 ovsrcu_postpone(free, partition);
839 if (--subtable->n_rules == 0) {
840 destroy_subtable(cls, subtable);
841 } else if (subtable->max_priority == cls_match->priority
842 && --subtable->max_count == 0) {
843 /* Find the new 'max_priority' and 'max_count'. */
844 struct cls_match *head;
845 unsigned int max_priority = 0;
847 CMAP_FOR_EACH (head, cmap_node, &subtable->rules) {
848 if (head->priority > max_priority) {
849 max_priority = head->priority;
850 subtable->max_count = 1;
851 } else if (head->priority == max_priority) {
852 ++subtable->max_count;
855 subtable->max_priority = max_priority;
856 pvector_change_priority(&cls->subtables, subtable, max_priority);
861 rule->cls_match = NULL;
862 ovsrcu_postpone(free, cls_match);
863 ovs_mutex_unlock(&cls->mutex);
866 /* Prefix tree context. Valid when 'lookup_done' is true. Can skip all
867 * subtables which have a prefix match on the trie field, but whose prefix
868 * length is not indicated in 'match_plens'. For example, a subtable that
869 * has a 8-bit trie field prefix match can be skipped if
870 * !be_get_bit_at(&match_plens, 8 - 1). If skipped, 'maskbits' prefix bits
871 * must be unwildcarded to make datapath flow only match packets it should. */
873 const struct cls_trie *trie;
874 bool lookup_done; /* Status of the lookup. */
875 uint8_t be32ofs; /* U32 offset of the field in question. */
876 unsigned int maskbits; /* Prefix length needed to avoid false matches. */
877 union mf_value match_plens; /* Bitmask of prefix lengths with possible
882 trie_ctx_init(struct trie_ctx *ctx, const struct cls_trie *trie)
885 ctx->be32ofs = trie->field->flow_be32ofs;
886 ctx->lookup_done = false;
889 /* Finds and returns the highest-priority rule in 'cls' that matches 'flow'.
890 * Returns a null pointer if no rules in 'cls' match 'flow'. If multiple rules
891 * of equal priority match 'flow', returns one arbitrarily.
893 * If a rule is found and 'wc' is non-null, bitwise-OR's 'wc' with the
894 * set of bits that were significant in the lookup. At some point
895 * earlier, 'wc' should have been initialized (e.g., by
896 * flow_wildcards_init_catchall()). */
898 classifier_lookup(const struct classifier *cls, const struct flow *flow,
899 struct flow_wildcards *wc)
901 const struct cls_partition *partition;
903 int64_t best_priority = -1;
904 const struct cls_match *best;
905 struct trie_ctx trie_ctx[CLS_MAX_TRIES];
906 struct cls_subtable *subtable;
908 /* Synchronize for cls->n_tries and subtable->trie_plen. They can change
909 * when table configuration changes, which happens typically only on
911 atomic_thread_fence(memory_order_acquire);
913 /* Determine 'tags' such that, if 'subtable->tag' doesn't intersect them,
914 * then 'flow' cannot possibly match in 'subtable':
916 * - If flow->metadata maps to a given 'partition', then we can use
917 * 'tags' for 'partition->tags'.
919 * - If flow->metadata has no partition, then no rule in 'cls' has an
920 * exact-match for flow->metadata. That means that we don't need to
921 * search any subtable that includes flow->metadata in its mask.
923 * In either case, we always need to search any cls_subtables that do not
924 * include flow->metadata in its mask. One way to do that would be to
925 * check the "cls_subtable"s explicitly for that, but that would require an
926 * extra branch per subtable. Instead, we mark such a cls_subtable's
927 * 'tags' as TAG_ALL and make sure that 'tags' is never empty. This means
928 * that 'tags' always intersects such a cls_subtable's 'tags', so we don't
929 * need a special case.
931 partition = (cmap_is_empty(&cls->partitions)
933 : find_partition(cls, flow->metadata,
934 hash_metadata(flow->metadata)));
935 tags = partition ? partition->tags : TAG_ARBITRARY;
937 /* Initialize trie contexts for match_find_wc(). */
938 for (int i = 0; i < cls->n_tries; i++) {
939 trie_ctx_init(&trie_ctx[i], &cls->tries[i]);
943 PVECTOR_FOR_EACH_PRIORITY(subtable, best_priority, 2,
944 sizeof(struct cls_subtable), &cls->subtables) {
945 struct cls_match *rule;
947 if (!tag_intersects(tags, subtable->tag)) {
951 rule = find_match_wc(subtable, flow, trie_ctx, cls->n_tries, wc);
952 if (rule && (int64_t)rule->priority > best_priority) {
953 best_priority = (int64_t)rule->priority;
958 return best ? best->cls_rule : NULL;
961 /* Returns true if 'target' satisifies 'match', that is, if each bit for which
962 * 'match' specifies a particular value has the correct value in 'target'.
964 * 'flow' and 'mask' have the same mask! */
966 miniflow_and_mask_matches_miniflow(const struct miniflow *flow,
967 const struct minimask *mask,
968 const struct miniflow *target)
970 const uint32_t *flowp = miniflow_get_u32_values(flow);
971 const uint32_t *maskp = miniflow_get_u32_values(&mask->masks);
974 MINIFLOW_FOR_EACH_IN_MAP(target_u32, target, mask->masks.map) {
975 if ((*flowp++ ^ target_u32) & *maskp++) {
983 /* For each miniflow in 'flows' performs a classifier lookup writing the result
984 * into the corresponding slot in 'rules'.
986 * This function is optimized for use in the userspace datapath and therefore
987 * does not implement a lot of features available in the standard
988 * classifier_lookup() function. Specifically, it does not implement
989 * priorities, instead returning any rule which matches the flow.
991 * Returns true if all flows found a corresponding rule. */
993 classifier_lookup_miniflow_batch(const struct classifier *cls,
994 const struct miniflow *flows[],
995 struct cls_rule *rules[], const size_t cnt)
997 /* The batch size 16 was experimentally found faster than 8 or 32. */
998 typedef uint16_t map_type;
999 #define MAP_BITS (sizeof(map_type) * CHAR_BIT)
1001 struct cls_subtable *subtable;
1002 const int n_maps = DIV_ROUND_UP(cnt, MAP_BITS);
1004 #if !defined(__CHECKER__) && !defined(_WIN32)
1005 map_type maps[n_maps];
1007 map_type maps[DIV_ROUND_UP(CLASSIFIER_MAX_BATCH, MAP_BITS)];
1008 ovs_assert(n_maps <= CLASSIFIER_MAX_BATCH);
1010 BUILD_ASSERT_DECL(sizeof *maps * CHAR_BIT == MAP_BITS);
1012 memset(maps, 0xff, sizeof maps);
1013 if (cnt % MAP_BITS) {
1014 maps[n_maps - 1] >>= MAP_BITS - cnt % MAP_BITS; /* Clear extra bits. */
1016 memset(rules, 0, cnt * sizeof *rules);
1018 PVECTOR_FOR_EACH (subtable, &cls->subtables) {
1019 const struct miniflow **mfs = flows;
1020 struct cls_rule **results = rules;
1021 map_type remains = 0;
1024 BUILD_ASSERT_DECL(sizeof remains == sizeof *maps);
1026 for (m = 0; m < n_maps; m++, mfs += MAP_BITS, results += MAP_BITS) {
1027 uint32_t hashes[MAP_BITS];
1028 const struct cmap_node *nodes[MAP_BITS];
1029 unsigned long map = maps[m];
1033 continue; /* Skip empty ones. */
1036 /* Compute hashes for the unfound flows. */
1037 ULONG_FOR_EACH_1(i, map) {
1038 hashes[i] = miniflow_hash_in_minimask(mfs[i], &subtable->mask,
1042 map = cmap_find_batch(&subtable->rules, map, hashes, nodes);
1043 /* Check results. */
1044 ULONG_FOR_EACH_1(i, map) {
1045 struct cls_match *rule;
1047 CMAP_NODE_FOR_EACH (rule, cmap_node, nodes[i]) {
1048 if (OVS_LIKELY(miniflow_and_mask_matches_miniflow(
1049 &rule->flow, &subtable->mask,
1051 results[i] = rule->cls_rule;
1055 ULONG_SET0(map, i); /* Did not match. */
1057 ; /* Keep Sparse happy. */
1059 maps[m] &= ~map; /* Clear the found rules. */
1063 return true; /* All found. */
1070 /* Finds and returns a rule in 'cls' with exactly the same priority and
1071 * matching criteria as 'target'. Returns a null pointer if 'cls' doesn't
1072 * contain an exact match. */
1074 classifier_find_rule_exactly(const struct classifier *cls,
1075 const struct cls_rule *target)
1076 OVS_EXCLUDED(cls->mutex)
1078 struct cls_match *head, *rule;
1079 struct cls_subtable *subtable;
1081 ovs_mutex_lock(&cls->mutex);
1082 subtable = find_subtable(cls, &target->match.mask);
1087 /* Skip if there is no hope. */
1088 if (target->priority > subtable->max_priority) {
1092 head = find_equal(subtable, &target->match.flow,
1093 miniflow_hash_in_minimask(&target->match.flow,
1094 &target->match.mask, 0));
1095 FOR_EACH_RULE_IN_LIST (rule, head) {
1096 if (target->priority >= rule->priority) {
1097 ovs_mutex_unlock(&cls->mutex);
1098 return target->priority == rule->priority ? rule->cls_rule : NULL;
1102 ovs_mutex_unlock(&cls->mutex);
1106 /* Finds and returns a rule in 'cls' with priority 'priority' and exactly the
1107 * same matching criteria as 'target'. Returns a null pointer if 'cls' doesn't
1108 * contain an exact match. */
1110 classifier_find_match_exactly(const struct classifier *cls,
1111 const struct match *target,
1112 unsigned int priority)
1114 struct cls_rule *retval;
1117 cls_rule_init(&cr, target, priority);
1118 retval = classifier_find_rule_exactly(cls, &cr);
1119 cls_rule_destroy(&cr);
1124 /* Checks if 'target' would overlap any other rule in 'cls'. Two rules are
1125 * considered to overlap if both rules have the same priority and a packet
1126 * could match both. */
1128 classifier_rule_overlaps(const struct classifier *cls,
1129 const struct cls_rule *target)
1130 OVS_EXCLUDED(cls->mutex)
1132 struct cls_subtable *subtable;
1133 int64_t stop_at_priority = (int64_t)target->priority - 1;
1135 ovs_mutex_lock(&cls->mutex);
1136 /* Iterate subtables in the descending max priority order. */
1137 PVECTOR_FOR_EACH_PRIORITY (subtable, stop_at_priority, 2,
1138 sizeof(struct cls_subtable), &cls->subtables) {
1139 uint32_t storage[FLOW_U32S];
1140 struct minimask mask;
1141 struct cls_match *head;
1143 minimask_combine(&mask, &target->match.mask, &subtable->mask, storage);
1144 CMAP_FOR_EACH (head, cmap_node, &subtable->rules) {
1145 struct cls_match *rule;
1147 FOR_EACH_RULE_IN_LIST (rule, head) {
1148 if (rule->priority < target->priority) {
1149 break; /* Rules in descending priority order. */
1151 if (rule->priority == target->priority
1152 && miniflow_equal_in_minimask(&target->match.flow,
1153 &rule->flow, &mask)) {
1154 ovs_mutex_unlock(&cls->mutex);
1161 ovs_mutex_unlock(&cls->mutex);
1165 /* Returns true if 'rule' exactly matches 'criteria' or if 'rule' is more
1166 * specific than 'criteria'. That is, 'rule' matches 'criteria' and this
1167 * function returns true if, for every field:
1169 * - 'criteria' and 'rule' specify the same (non-wildcarded) value for the
1172 * - 'criteria' wildcards the field,
1174 * Conversely, 'rule' does not match 'criteria' and this function returns false
1175 * if, for at least one field:
1177 * - 'criteria' and 'rule' specify different values for the field, or
1179 * - 'criteria' specifies a value for the field but 'rule' wildcards it.
1181 * Equivalently, the truth table for whether a field matches is:
1186 * r +---------+---------+
1187 * i wild | yes | yes |
1189 * e +---------+---------+
1190 * r exact | no |if values|
1192 * a +---------+---------+
1194 * This is the matching rule used by OpenFlow 1.0 non-strict OFPT_FLOW_MOD
1195 * commands and by OpenFlow 1.0 aggregate and flow stats.
1197 * Ignores rule->priority. */
1199 cls_rule_is_loose_match(const struct cls_rule *rule,
1200 const struct minimatch *criteria)
1202 return (!minimask_has_extra(&rule->match.mask, &criteria->mask)
1203 && miniflow_equal_in_minimask(&rule->match.flow, &criteria->flow,
1210 rule_matches(const struct cls_match *rule, const struct cls_rule *target)
1213 || miniflow_equal_in_minimask(&rule->flow,
1214 &target->match.flow,
1215 &target->match.mask));
1218 static struct cls_match *
1219 search_subtable(const struct cls_subtable *subtable,
1220 struct cls_cursor *cursor)
1223 || !minimask_has_extra(&subtable->mask, &cursor->target->match.mask)) {
1224 struct cls_match *rule;
1226 CMAP_CURSOR_FOR_EACH (rule, cmap_node, &cursor->rules,
1228 if (rule_matches(rule, cursor->target)) {
1236 /* Initializes 'cursor' for iterating through rules in 'cls', and returns the
1237 * first matching cls_rule via '*pnode', or NULL if there are no matches.
1239 * - If 'target' is null, the cursor will visit every rule in 'cls'.
1241 * - If 'target' is nonnull, the cursor will visit each 'rule' in 'cls'
1242 * such that cls_rule_is_loose_match(rule, target) returns true.
1244 * Ignores target->priority. */
1245 struct cls_cursor cls_cursor_start(const struct classifier *cls,
1246 const struct cls_rule *target,
1248 OVS_NO_THREAD_SAFETY_ANALYSIS
1250 struct cls_cursor cursor;
1251 struct cls_subtable *subtable;
1255 cursor.target = target && !cls_rule_is_catchall(target) ? target : NULL;
1258 /* Find first rule. */
1259 ovs_mutex_lock(&cursor.cls->mutex);
1260 CMAP_CURSOR_FOR_EACH (subtable, cmap_node, &cursor.subtables,
1261 &cursor.cls->subtables_map) {
1262 struct cls_match *rule = search_subtable(subtable, &cursor);
1265 cursor.subtable = subtable;
1266 cursor.rule = rule->cls_rule;
1271 /* Leave locked if requested and have a rule. */
1272 if (safe || !cursor.rule) {
1273 ovs_mutex_unlock(&cursor.cls->mutex);
1278 static struct cls_rule *
1279 cls_cursor_next(struct cls_cursor *cursor)
1280 OVS_NO_THREAD_SAFETY_ANALYSIS
1282 struct cls_match *rule = cursor->rule->cls_match;
1283 const struct cls_subtable *subtable;
1284 struct cls_match *next;
1286 next = next_rule_in_list__(rule);
1287 if (next->priority < rule->priority) {
1288 return next->cls_rule;
1291 /* 'next' is the head of the list, that is, the rule that is included in
1292 * the subtable's map. (This is important when the classifier contains
1293 * rules that differ only in priority.) */
1295 CMAP_CURSOR_FOR_EACH_CONTINUE (rule, cmap_node, &cursor->rules) {
1296 if (rule_matches(rule, cursor->target)) {
1297 return rule->cls_rule;
1301 subtable = cursor->subtable;
1302 CMAP_CURSOR_FOR_EACH_CONTINUE (subtable, cmap_node, &cursor->subtables) {
1303 rule = search_subtable(subtable, cursor);
1305 cursor->subtable = subtable;
1306 return rule->cls_rule;
1313 /* Sets 'cursor->rule' to the next matching cls_rule in 'cursor''s iteration,
1314 * or to null if all matching rules have been visited. */
1316 cls_cursor_advance(struct cls_cursor *cursor)
1317 OVS_NO_THREAD_SAFETY_ANALYSIS
1320 ovs_mutex_lock(&cursor->cls->mutex);
1322 cursor->rule = cls_cursor_next(cursor);
1323 if (cursor->safe || !cursor->rule) {
1324 ovs_mutex_unlock(&cursor->cls->mutex);
1328 static struct cls_subtable *
1329 find_subtable(const struct classifier *cls, const struct minimask *mask)
1330 OVS_REQUIRES(cls->mutex)
1332 struct cls_subtable *subtable;
1334 CMAP_FOR_EACH_WITH_HASH (subtable, cmap_node, minimask_hash(mask, 0),
1335 &cls->subtables_map) {
1336 if (minimask_equal(mask, &subtable->mask)) {
1343 /* The new subtable will be visible to the readers only after this. */
1344 static struct cls_subtable *
1345 insert_subtable(struct classifier *cls, const struct minimask *mask)
1346 OVS_REQUIRES(cls->mutex)
1348 uint32_t hash = minimask_hash(mask, 0);
1349 struct cls_subtable *subtable;
1351 struct flow_wildcards old, new;
1353 int count = count_1bits(mask->masks.map);
1355 subtable = xzalloc(sizeof *subtable - sizeof mask->masks.inline_values
1356 + MINIFLOW_VALUES_SIZE(count));
1357 cmap_init(&subtable->rules);
1358 miniflow_clone_inline(&subtable->mask.masks, &mask->masks, count);
1360 /* Init indices for segmented lookup, if any. */
1361 flow_wildcards_init_catchall(&new);
1364 for (i = 0; i < cls->n_flow_segments; i++) {
1365 flow_wildcards_fold_minimask_range(&new, mask, prev,
1366 cls->flow_segments[i]);
1367 /* Add an index if it adds mask bits. */
1368 if (!flow_wildcards_equal(&new, &old)) {
1369 cmap_init(&subtable->indices[index]);
1370 subtable->index_ofs[index] = cls->flow_segments[i];
1374 prev = cls->flow_segments[i];
1376 /* Check if the rest of the subtable's mask adds any bits,
1377 * and remove the last index if it doesn't. */
1379 flow_wildcards_fold_minimask_range(&new, mask, prev, FLOW_U32S);
1380 if (flow_wildcards_equal(&new, &old)) {
1382 subtable->index_ofs[index] = 0;
1383 cmap_destroy(&subtable->indices[index]);
1386 subtable->n_indices = index;
1388 subtable->tag = (minimask_get_metadata_mask(mask) == OVS_BE64_MAX
1389 ? tag_create_deterministic(hash)
1392 for (i = 0; i < cls->n_tries; i++) {
1393 subtable->trie_plen[i] = minimask_get_prefix_len(mask,
1394 cls->tries[i].field);
1398 ovsrcu_set_hidden(&subtable->ports_trie, NULL);
1399 subtable->ports_mask_len
1400 = 32 - ctz32(ntohl(MINIFLOW_GET_BE32(&mask->masks, tp_src)));
1402 cmap_insert(&cls->subtables_map, &subtable->cmap_node, hash);
1408 destroy_subtable(struct classifier *cls, struct cls_subtable *subtable)
1409 OVS_REQUIRES(cls->mutex)
1413 pvector_remove(&cls->subtables, subtable);
1414 trie_destroy(&subtable->ports_trie);
1416 for (i = 0; i < subtable->n_indices; i++) {
1417 cmap_destroy(&subtable->indices[i]);
1419 cmap_remove(&cls->subtables_map, &subtable->cmap_node,
1420 minimask_hash(&subtable->mask, 0));
1421 minimask_destroy(&subtable->mask);
1422 cmap_destroy(&subtable->rules);
1423 ovsrcu_postpone(free, subtable);
1431 static unsigned int be_get_bit_at(const ovs_be32 value[], unsigned int ofs);
1433 /* Return 'true' if can skip rest of the subtable based on the prefix trie
1434 * lookup results. */
1436 check_tries(struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries,
1437 const unsigned int field_plen[CLS_MAX_TRIES],
1438 const struct range ofs, const struct flow *flow,
1439 struct flow_wildcards *wc)
1443 /* Check if we could avoid fully unwildcarding the next level of
1444 * fields using the prefix tries. The trie checks are done only as
1445 * needed to avoid folding in additional bits to the wildcards mask. */
1446 for (j = 0; j < n_tries; j++) {
1447 /* Is the trie field relevant for this subtable? */
1448 if (field_plen[j]) {
1449 struct trie_ctx *ctx = &trie_ctx[j];
1450 uint8_t be32ofs = ctx->be32ofs;
1452 /* Is the trie field within the current range of fields? */
1453 if (be32ofs >= ofs.start && be32ofs < ofs.end) {
1454 /* On-demand trie lookup. */
1455 if (!ctx->lookup_done) {
1456 memset(&ctx->match_plens, 0, sizeof ctx->match_plens);
1457 ctx->maskbits = trie_lookup(ctx->trie, flow,
1459 ctx->lookup_done = true;
1461 /* Possible to skip the rest of the subtable if subtable's
1462 * prefix on the field is not included in the lookup result. */
1463 if (!be_get_bit_at(&ctx->match_plens.be32, field_plen[j] - 1)) {
1464 /* We want the trie lookup to never result in unwildcarding
1465 * any bits that would not be unwildcarded otherwise.
1466 * Since the trie is shared by the whole classifier, it is
1467 * possible that the 'maskbits' contain bits that are
1468 * irrelevant for the partition relevant for the current
1469 * packet. Hence the checks below. */
1471 /* Check that the trie result will not unwildcard more bits
1472 * than this subtable would otherwise. */
1473 if (ctx->maskbits <= field_plen[j]) {
1474 /* Unwildcard the bits and skip the rest. */
1475 mask_set_prefix_bits(wc, be32ofs, ctx->maskbits);
1476 /* Note: Prerequisite already unwildcarded, as the only
1477 * prerequisite of the supported trie lookup fields is
1478 * the ethertype, which is always unwildcarded. */
1481 /* Can skip if the field is already unwildcarded. */
1482 if (mask_prefix_bits_set(wc, be32ofs, ctx->maskbits)) {
1492 /* Returns true if 'target' satisifies 'flow'/'mask', that is, if each bit
1493 * for which 'flow', for which 'mask' has a bit set, specifies a particular
1494 * value has the correct value in 'target'.
1496 * This function is equivalent to miniflow_equal_flow_in_minimask(flow,
1497 * target, mask) but this is faster because of the invariant that
1498 * flow->map and mask->masks.map are the same, and that this version
1499 * takes the 'wc'. */
1501 miniflow_and_mask_matches_flow(const struct miniflow *flow,
1502 const struct minimask *mask,
1503 const struct flow *target)
1505 const uint32_t *flowp = miniflow_get_u32_values(flow);
1506 const uint32_t *maskp = miniflow_get_u32_values(&mask->masks);
1509 MAP_FOR_EACH_INDEX(idx, mask->masks.map) {
1510 uint32_t diff = (*flowp++ ^ flow_u32_value(target, idx)) & *maskp++;
1520 static inline struct cls_match *
1521 find_match(const struct cls_subtable *subtable, const struct flow *flow,
1524 struct cls_match *rule;
1526 CMAP_FOR_EACH_WITH_HASH (rule, cmap_node, hash, &subtable->rules) {
1527 if (miniflow_and_mask_matches_flow(&rule->flow, &subtable->mask,
1536 /* Returns true if 'target' satisifies 'flow'/'mask', that is, if each bit
1537 * for which 'flow', for which 'mask' has a bit set, specifies a particular
1538 * value has the correct value in 'target'.
1540 * This function is equivalent to miniflow_and_mask_matches_flow() but this
1541 * version fills in the mask bits in 'wc'. */
1543 miniflow_and_mask_matches_flow_wc(const struct miniflow *flow,
1544 const struct minimask *mask,
1545 const struct flow *target,
1546 struct flow_wildcards *wc)
1548 const uint32_t *flowp = miniflow_get_u32_values(flow);
1549 const uint32_t *maskp = miniflow_get_u32_values(&mask->masks);
1552 MAP_FOR_EACH_INDEX(idx, mask->masks.map) {
1553 uint32_t mask = *maskp++;
1554 uint32_t diff = (*flowp++ ^ flow_u32_value(target, idx)) & mask;
1557 /* Only unwildcard if none of the differing bits is already
1559 if (!(flow_u32_value(&wc->masks, idx) & diff)) {
1560 /* Keep one bit of the difference. */
1561 *flow_u32_lvalue(&wc->masks, idx) |= rightmost_1bit(diff);
1565 /* Fill in the bits that were looked at. */
1566 *flow_u32_lvalue(&wc->masks, idx) |= mask;
1572 /* Unwildcard the fields looked up so far, if any. */
1574 fill_range_wc(const struct cls_subtable *subtable, struct flow_wildcards *wc,
1578 flow_wildcards_fold_minimask_range(wc, &subtable->mask, 0, to);
1582 static struct cls_match *
1583 find_match_wc(const struct cls_subtable *subtable, const struct flow *flow,
1584 struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries,
1585 struct flow_wildcards *wc)
1587 uint32_t basis = 0, hash;
1588 struct cls_match *rule = NULL;
1592 if (OVS_UNLIKELY(!wc)) {
1593 return find_match(subtable, flow,
1594 flow_hash_in_minimask(flow, &subtable->mask, 0));
1598 /* Try to finish early by checking fields in segments. */
1599 for (i = 0; i < subtable->n_indices; i++) {
1600 const struct cmap_node *inode;
1602 ofs.end = subtable->index_ofs[i];
1604 if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow,
1606 /* 'wc' bits for the trie field set, now unwildcard the preceding
1607 * bits used so far. */
1608 fill_range_wc(subtable, wc, ofs.start);
1611 hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
1613 inode = cmap_find(&subtable->indices[i], hash);
1615 /* No match, can stop immediately, but must fold in the bits
1616 * used in lookup so far. */
1617 fill_range_wc(subtable, wc, ofs.end);
1621 /* If we have narrowed down to a single rule already, check whether
1622 * that rule matches. Either way, we're done.
1624 * (Rare) hash collisions may cause us to miss the opportunity for this
1626 if (!cmap_node_next(inode)) {
1627 ASSIGN_CONTAINER(rule, inode - i, index_nodes);
1628 if (miniflow_and_mask_matches_flow_wc(&rule->flow, &subtable->mask,
1634 ofs.start = ofs.end;
1636 ofs.end = FLOW_U32S;
1637 /* Trie check for the final range. */
1638 if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow, wc)) {
1639 fill_range_wc(subtable, wc, ofs.start);
1642 hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
1644 rule = find_match(subtable, flow, hash);
1645 if (!rule && subtable->ports_mask_len) {
1646 /* Ports are always part of the final range, if any.
1647 * No match was found for the ports. Use the ports trie to figure out
1648 * which ports bits to unwildcard. */
1650 ovs_be32 value, plens, mask;
1652 mask = MINIFLOW_GET_BE32(&subtable->mask.masks, tp_src);
1653 value = ((OVS_FORCE ovs_be32 *)flow)[TP_PORTS_OFS32] & mask;
1654 mbits = trie_lookup_value(&subtable->ports_trie, &value, &plens, 32);
1656 ((OVS_FORCE ovs_be32 *)&wc->masks)[TP_PORTS_OFS32] |=
1657 mask & htonl(~0 << (32 - mbits));
1659 /* Unwildcard all bits in the mask upto the ports, as they were used
1660 * to determine there is no match. */
1661 fill_range_wc(subtable, wc, TP_PORTS_OFS32);
1665 /* Must unwildcard all the fields, as they were looked at. */
1666 flow_wildcards_fold_minimask(wc, &subtable->mask);
1670 static struct cls_match *
1671 find_equal(struct cls_subtable *subtable, const struct miniflow *flow,
1674 struct cls_match *head;
1676 CMAP_FOR_EACH_WITH_HASH (head, cmap_node, hash, &subtable->rules) {
1677 if (miniflow_equal(&head->flow, flow)) {
1685 * As the readers are operating concurrently with the modifications, a
1686 * concurrent reader may or may not see the new rule, depending on how
1687 * the concurrent events overlap with each other. This is no
1688 * different from the former locked behavior, but there the visibility
1689 * of the new rule only depended on the timing of the locking
1692 * The new rule is first added to the segment indices, so the readers
1693 * may find the rule in the indices before the rule is visible in the
1694 * subtables 'rules' map. This may result in us losing the
1695 * opportunity to quit lookups earlier, resulting in sub-optimal
1696 * wildcarding. This will be fixed by forthcoming revalidation always
1697 * scheduled after flow table changes.
1699 * Similar behavior may happen due to us removing the overlapping rule
1700 * (if any) from the indices only after the new rule has been added.
1702 * The subtable's max priority is updated only after the rule is
1703 * inserted, so the concurrent readers may not see the rule, as the
1704 * updated priority ordered subtable list will only be visible after
1705 * the subtable's max priority is updated.
1707 * Similarly, the classifier's partitions for new rules are updated by
1708 * the caller after this function, so the readers may keep skipping
1709 * the subtable until they see the updated partitions.
1711 static struct cls_match *
1712 insert_rule(struct classifier *cls, struct cls_subtable *subtable,
1713 struct cls_rule *new_rule)
1714 OVS_REQUIRES(cls->mutex)
1716 struct cls_match *old = NULL;
1717 struct cls_match *new = cls_match_alloc(new_rule);
1718 struct cls_match *head;
1720 uint32_t basis = 0, hash, ihash[CLS_MAX_INDICES];
1721 uint8_t prev_be32ofs = 0;
1723 /* Add new node to segment indices. */
1724 for (i = 0; i < subtable->n_indices; i++) {
1725 ihash[i] = minimatch_hash_range(&new_rule->match, prev_be32ofs,
1726 subtable->index_ofs[i], &basis);
1727 cmap_insert(&subtable->indices[i], &new->index_nodes[i], ihash[i]);
1728 prev_be32ofs = subtable->index_ofs[i];
1730 hash = minimatch_hash_range(&new_rule->match, prev_be32ofs, FLOW_U32S,
1732 head = find_equal(subtable, &new_rule->match.flow, hash);
1734 cmap_insert(&subtable->rules, &new->cmap_node, hash);
1735 list_init(&new->list);
1738 /* Scan the list for the insertion point that will keep the list in
1739 * order of decreasing priority. */
1740 struct cls_match *rule;
1742 FOR_EACH_RULE_IN_LIST (rule, head) {
1743 if (new->priority >= rule->priority) {
1745 /* 'new' is the new highest-priority flow in the list. */
1746 cmap_replace(&subtable->rules, &rule->cmap_node,
1747 &new->cmap_node, hash);
1750 if (new->priority == rule->priority) {
1751 list_replace(&new->list, &rule->list);
1754 list_insert(&rule->list, &new->list);
1760 /* Insert 'new' at the end of the list. */
1761 list_push_back(&head->list, &new->list);
1766 subtable->n_rules++;
1768 /* Rule was added, not replaced. Update 'subtable's 'max_priority'
1769 * and 'max_count', if necessary. */
1770 if (subtable->n_rules == 1) {
1771 subtable->max_priority = new->priority;
1772 subtable->max_count = 1;
1773 pvector_insert(&cls->subtables, subtable, new->priority);
1774 } else if (subtable->max_priority == new->priority) {
1775 ++subtable->max_count;
1776 } else if (new->priority > subtable->max_priority) {
1777 subtable->max_priority = new->priority;
1778 subtable->max_count = 1;
1779 pvector_change_priority(&cls->subtables, subtable, new->priority);
1782 /* Remove old node from indices. */
1783 for (i = 0; i < subtable->n_indices; i++) {
1784 cmap_remove(&subtable->indices[i], &old->index_nodes[i], ihash[i]);
1790 static struct cls_match *
1791 next_rule_in_list__(struct cls_match *rule)
1792 OVS_NO_THREAD_SAFETY_ANALYSIS
1794 struct cls_match *next = NULL;
1795 next = OBJECT_CONTAINING(rule->list.next, next, list);
1799 static struct cls_match *
1800 next_rule_in_list(struct cls_match *rule)
1802 struct cls_match *next = next_rule_in_list__(rule);
1803 return next->priority < rule->priority ? next : NULL;
1806 /* A longest-prefix match tree. */
1808 uint32_t prefix; /* Prefix bits for this node, MSB first. */
1809 uint8_t n_bits; /* Never zero, except for the root node. */
1810 unsigned int n_rules; /* Number of rules that have this prefix. */
1811 rcu_trie_ptr edges[2]; /* Both NULL if leaf. */
1814 /* Max bits per node. Must fit in struct trie_node's 'prefix'.
1815 * Also tested with 16, 8, and 5 to stress the implementation. */
1816 #define TRIE_PREFIX_BITS 32
1818 /* Return at least 'plen' bits of the 'prefix', starting at bit offset 'ofs'.
1819 * Prefixes are in the network byte order, and the offset 0 corresponds to
1820 * the most significant bit of the first byte. The offset can be read as
1821 * "how many bits to skip from the start of the prefix starting at 'pr'". */
1823 raw_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
1827 pr += ofs / 32; /* Where to start. */
1828 ofs %= 32; /* How many bits to skip at 'pr'. */
1830 prefix = ntohl(*pr) << ofs; /* Get the first 32 - ofs bits. */
1831 if (plen > 32 - ofs) { /* Need more than we have already? */
1832 prefix |= ntohl(*++pr) >> (32 - ofs);
1834 /* Return with possible unwanted bits at the end. */
1838 /* Return min(TRIE_PREFIX_BITS, plen) bits of the 'prefix', starting at bit
1839 * offset 'ofs'. Prefixes are in the network byte order, and the offset 0
1840 * corresponds to the most significant bit of the first byte. The offset can
1841 * be read as "how many bits to skip from the start of the prefix starting at
1844 trie_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
1849 if (plen > TRIE_PREFIX_BITS) {
1850 plen = TRIE_PREFIX_BITS; /* Get at most TRIE_PREFIX_BITS. */
1852 /* Return with unwanted bits cleared. */
1853 return raw_get_prefix(pr, ofs, plen) & ~0u << (32 - plen);
1856 /* Return the number of equal bits in 'n_bits' of 'prefix's MSBs and a 'value'
1857 * starting at "MSB 0"-based offset 'ofs'. */
1859 prefix_equal_bits(uint32_t prefix, unsigned int n_bits, const ovs_be32 value[],
1862 uint64_t diff = prefix ^ raw_get_prefix(value, ofs, n_bits);
1863 /* Set the bit after the relevant bits to limit the result. */
1864 return raw_clz64(diff << 32 | UINT64_C(1) << (63 - n_bits));
1867 /* Return the number of equal bits in 'node' prefix and a 'prefix' of length
1868 * 'plen', starting at "MSB 0"-based offset 'ofs'. */
1870 trie_prefix_equal_bits(const struct trie_node *node, const ovs_be32 prefix[],
1871 unsigned int ofs, unsigned int plen)
1873 return prefix_equal_bits(node->prefix, MIN(node->n_bits, plen - ofs),
1877 /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' can
1878 * be greater than 31. */
1880 be_get_bit_at(const ovs_be32 value[], unsigned int ofs)
1882 return (((const uint8_t *)value)[ofs / 8] >> (7 - ofs % 8)) & 1u;
1885 /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' must
1886 * be between 0 and 31, inclusive. */
1888 get_bit_at(const uint32_t prefix, unsigned int ofs)
1890 return (prefix >> (31 - ofs)) & 1u;
1893 /* Create new branch. */
1894 static struct trie_node *
1895 trie_branch_create(const ovs_be32 *prefix, unsigned int ofs, unsigned int plen,
1896 unsigned int n_rules)
1898 struct trie_node *node = xmalloc(sizeof *node);
1900 node->prefix = trie_get_prefix(prefix, ofs, plen);
1902 if (plen <= TRIE_PREFIX_BITS) {
1903 node->n_bits = plen;
1904 ovsrcu_set_hidden(&node->edges[0], NULL);
1905 ovsrcu_set_hidden(&node->edges[1], NULL);
1906 node->n_rules = n_rules;
1907 } else { /* Need intermediate nodes. */
1908 struct trie_node *subnode = trie_branch_create(prefix,
1909 ofs + TRIE_PREFIX_BITS,
1910 plen - TRIE_PREFIX_BITS,
1912 int bit = get_bit_at(subnode->prefix, 0);
1913 node->n_bits = TRIE_PREFIX_BITS;
1914 ovsrcu_set_hidden(&node->edges[bit], subnode);
1915 ovsrcu_set_hidden(&node->edges[!bit], NULL);
1922 trie_node_destroy(const struct trie_node *node)
1924 ovsrcu_postpone(free, CONST_CAST(struct trie_node *, node));
1927 /* Copy a trie node for modification and postpone delete the old one. */
1928 static struct trie_node *
1929 trie_node_rcu_realloc(const struct trie_node *node)
1931 struct trie_node *new_node = xmalloc(sizeof *node);
1934 trie_node_destroy(node);
1939 /* May only be called while holding the classifier mutex. */
1941 trie_destroy(rcu_trie_ptr *trie)
1943 struct trie_node *node = ovsrcu_get_protected(struct trie_node *, trie);
1946 ovsrcu_set_hidden(trie, NULL);
1947 trie_destroy(&node->edges[0]);
1948 trie_destroy(&node->edges[1]);
1949 trie_node_destroy(node);
1954 trie_is_leaf(const struct trie_node *trie)
1957 return !ovsrcu_get(struct trie_node *, &trie->edges[0])
1958 && !ovsrcu_get(struct trie_node *, &trie->edges[1]);
1962 mask_set_prefix_bits(struct flow_wildcards *wc, uint8_t be32ofs,
1963 unsigned int n_bits)
1965 ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
1968 for (i = 0; i < n_bits / 32; i++) {
1969 mask[i] = OVS_BE32_MAX;
1972 mask[i] |= htonl(~0u << (32 - n_bits % 32));
1977 mask_prefix_bits_set(const struct flow_wildcards *wc, uint8_t be32ofs,
1978 unsigned int n_bits)
1980 ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
1982 ovs_be32 zeroes = 0;
1984 for (i = 0; i < n_bits / 32; i++) {
1988 zeroes |= ~mask[i] & htonl(~0u << (32 - n_bits % 32));
1991 return !zeroes; /* All 'n_bits' bits set. */
1994 static rcu_trie_ptr *
1995 trie_next_edge(struct trie_node *node, const ovs_be32 value[],
1998 return node->edges + be_get_bit_at(value, ofs);
2001 static const struct trie_node *
2002 trie_next_node(const struct trie_node *node, const ovs_be32 value[],
2005 return ovsrcu_get(struct trie_node *,
2006 &node->edges[be_get_bit_at(value, ofs)]);
2009 /* Set the bit at ("MSB 0"-based) offset 'ofs'. 'ofs' can be greater than 31.
2012 be_set_bit_at(ovs_be32 value[], unsigned int ofs)
2014 ((uint8_t *)value)[ofs / 8] |= 1u << (7 - ofs % 8);
2017 /* Returns the number of bits in the prefix mask necessary to determine a
2018 * mismatch, in case there are longer prefixes in the tree below the one that
2020 * '*plens' will have a bit set for each prefix length that may have matching
2021 * rules. The caller is responsible for clearing the '*plens' prior to
2025 trie_lookup_value(const rcu_trie_ptr *trie, const ovs_be32 value[],
2026 ovs_be32 plens[], unsigned int n_bits)
2028 const struct trie_node *prev = NULL;
2029 const struct trie_node *node = ovsrcu_get(struct trie_node *, trie);
2030 unsigned int match_len = 0; /* Number of matching bits. */
2032 for (; node; prev = node, node = trie_next_node(node, value, match_len)) {
2033 unsigned int eqbits;
2034 /* Check if this edge can be followed. */
2035 eqbits = prefix_equal_bits(node->prefix, node->n_bits, value,
2037 match_len += eqbits;
2038 if (eqbits < node->n_bits) { /* Mismatch, nothing more to be found. */
2039 /* Bit at offset 'match_len' differed. */
2040 return match_len + 1; /* Includes the first mismatching bit. */
2042 /* Full match, check if rules exist at this prefix length. */
2043 if (node->n_rules > 0) {
2044 be_set_bit_at(plens, match_len - 1);
2046 if (match_len >= n_bits) {
2047 return n_bits; /* Full prefix. */
2050 /* node == NULL. Full match so far, but we tried to follow an
2051 * non-existing branch. Need to exclude the other branch if it exists
2052 * (it does not if we were called on an empty trie or 'prev' is a leaf
2054 return !prev || trie_is_leaf(prev) ? match_len : match_len + 1;
2058 trie_lookup(const struct cls_trie *trie, const struct flow *flow,
2059 union mf_value *plens)
2061 const struct mf_field *mf = trie->field;
2063 /* Check that current flow matches the prerequisites for the trie
2064 * field. Some match fields are used for multiple purposes, so we
2065 * must check that the trie is relevant for this flow. */
2066 if (mf_are_prereqs_ok(mf, flow)) {
2067 return trie_lookup_value(&trie->root,
2068 &((ovs_be32 *)flow)[mf->flow_be32ofs],
2069 &plens->be32, mf->n_bits);
2071 memset(plens, 0xff, sizeof *plens); /* All prefixes, no skipping. */
2072 return 0; /* Value not used in this case. */
2075 /* Returns the length of a prefix match mask for the field 'mf' in 'minimask'.
2076 * Returns the u32 offset to the miniflow data in '*miniflow_index', if
2077 * 'miniflow_index' is not NULL. */
2079 minimask_get_prefix_len(const struct minimask *minimask,
2080 const struct mf_field *mf)
2082 unsigned int n_bits = 0, mask_tz = 0; /* Non-zero when end of mask seen. */
2083 uint8_t u32_ofs = mf->flow_be32ofs;
2084 uint8_t u32_end = u32_ofs + mf->n_bytes / 4;
2086 for (; u32_ofs < u32_end; ++u32_ofs) {
2088 mask = ntohl((OVS_FORCE ovs_be32)minimask_get(minimask, u32_ofs));
2090 /* Validate mask, count the mask length. */
2093 return 0; /* No bits allowed after mask ended. */
2096 if (~mask & (~mask + 1)) {
2097 return 0; /* Mask not contiguous. */
2099 mask_tz = ctz32(mask);
2100 n_bits += 32 - mask_tz;
2108 * This is called only when mask prefix is known to be CIDR and non-zero.
2109 * Relies on the fact that the flow and mask have the same map, and since
2110 * the mask is CIDR, the storage for the flow field exists even if it
2111 * happened to be zeros.
2113 static const ovs_be32 *
2114 minimatch_get_prefix(const struct minimatch *match, const struct mf_field *mf)
2116 return miniflow_get_be32_values(&match->flow) +
2117 count_1bits(match->flow.map & ((UINT64_C(1) << mf->flow_be32ofs) - 1));
2120 /* Insert rule in to the prefix tree.
2121 * 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2124 trie_insert(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
2126 trie_insert_prefix(&trie->root,
2127 minimatch_get_prefix(&rule->match, trie->field), mlen);
2131 trie_insert_prefix(rcu_trie_ptr *edge, const ovs_be32 *prefix, int mlen)
2133 struct trie_node *node;
2136 /* Walk the tree. */
2137 for (; (node = ovsrcu_get_protected(struct trie_node *, edge));
2138 edge = trie_next_edge(node, prefix, ofs)) {
2139 unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
2141 if (eqbits < node->n_bits) {
2142 /* Mismatch, new node needs to be inserted above. */
2143 int old_branch = get_bit_at(node->prefix, eqbits);
2144 struct trie_node *new_parent;
2146 new_parent = trie_branch_create(prefix, ofs - eqbits, eqbits,
2147 ofs == mlen ? 1 : 0);
2148 /* Copy the node to modify it. */
2149 node = trie_node_rcu_realloc(node);
2150 /* Adjust the new node for its new position in the tree. */
2151 node->prefix <<= eqbits;
2152 node->n_bits -= eqbits;
2153 ovsrcu_set_hidden(&new_parent->edges[old_branch], node);
2155 /* Check if need a new branch for the new rule. */
2157 ovsrcu_set_hidden(&new_parent->edges[!old_branch],
2158 trie_branch_create(prefix, ofs, mlen - ofs,
2161 ovsrcu_set(edge, new_parent); /* Publish changes. */
2164 /* Full match so far. */
2167 /* Full match at the current node, rule needs to be added here. */
2172 /* Must insert a new tree branch for the new rule. */
2173 ovsrcu_set(edge, trie_branch_create(prefix, ofs, mlen - ofs, 1));
2176 /* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2179 trie_remove(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
2181 trie_remove_prefix(&trie->root,
2182 minimatch_get_prefix(&rule->match, trie->field), mlen);
2185 /* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2188 trie_remove_prefix(rcu_trie_ptr *root, const ovs_be32 *prefix, int mlen)
2190 struct trie_node *node;
2191 rcu_trie_ptr *edges[sizeof(union mf_value) * 8];
2192 int depth = 0, ofs = 0;
2194 /* Walk the tree. */
2195 for (edges[0] = root;
2196 (node = ovsrcu_get_protected(struct trie_node *, edges[depth]));
2197 edges[++depth] = trie_next_edge(node, prefix, ofs)) {
2198 unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
2200 if (eqbits < node->n_bits) {
2201 /* Mismatch, nothing to be removed. This should never happen, as
2202 * only rules in the classifier are ever removed. */
2203 break; /* Log a warning. */
2205 /* Full match so far. */
2209 /* Full prefix match at the current node, remove rule here. */
2210 if (!node->n_rules) {
2211 break; /* Log a warning. */
2215 /* Check if can prune the tree. */
2216 while (!node->n_rules) {
2217 struct trie_node *next,
2218 *edge0 = ovsrcu_get_protected(struct trie_node *,
2220 *edge1 = ovsrcu_get_protected(struct trie_node *,
2223 if (edge0 && edge1) {
2224 break; /* A branching point, cannot prune. */
2227 /* Else have at most one child node, remove this node. */
2228 next = edge0 ? edge0 : edge1;
2231 if (node->n_bits + next->n_bits > TRIE_PREFIX_BITS) {
2232 break; /* Cannot combine. */
2234 next = trie_node_rcu_realloc(next); /* Modify. */
2236 /* Combine node with next. */
2237 next->prefix = node->prefix | next->prefix >> node->n_bits;
2238 next->n_bits += node->n_bits;
2240 /* Update the parent's edge. */
2241 ovsrcu_set(edges[depth], next); /* Publish changes. */
2242 trie_node_destroy(node);
2244 if (next || !depth) {
2245 /* Branch not pruned or at root, nothing more to do. */
2248 node = ovsrcu_get_protected(struct trie_node *,
2254 /* Cannot go deeper. This should never happen, since only rules
2255 * that actually exist in the classifier are ever removed. */
2256 VLOG_WARN("Trying to remove non-existing rule from a prefix trie.");