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 * Does nothing if 'rule' has been already removed, or was never inserted.
777 * Returns the removed rule, or NULL, if it was already removed.
780 classifier_remove(struct classifier *cls, struct cls_rule *rule)
781 OVS_EXCLUDED(cls->mutex)
783 struct cls_partition *partition;
784 struct cls_match *cls_match;
785 struct cls_match *head;
786 struct cls_subtable *subtable;
788 uint32_t basis = 0, hash, ihash[CLS_MAX_INDICES];
789 uint8_t prev_be32ofs = 0;
791 ovs_mutex_lock(&cls->mutex);
792 cls_match = rule->cls_match;
795 goto unlock; /* Already removed. */
798 subtable = find_subtable(cls, &rule->match.mask);
799 ovs_assert(subtable);
801 if (subtable->ports_mask_len) {
802 ovs_be32 masked_ports = minimatch_get_ports(&rule->match);
804 trie_remove_prefix(&subtable->ports_trie,
805 &masked_ports, subtable->ports_mask_len);
807 for (i = 0; i < cls->n_tries; i++) {
808 if (subtable->trie_plen[i]) {
809 trie_remove(&cls->tries[i], rule, subtable->trie_plen[i]);
813 /* Remove rule node from indices. */
814 for (i = 0; i < subtable->n_indices; i++) {
815 ihash[i] = minimatch_hash_range(&rule->match, prev_be32ofs,
816 subtable->index_ofs[i], &basis);
817 cmap_remove(&subtable->indices[i], &cls_match->index_nodes[i],
819 prev_be32ofs = subtable->index_ofs[i];
821 hash = minimatch_hash_range(&rule->match, prev_be32ofs, FLOW_U32S, &basis);
823 head = find_equal(subtable, &rule->match.flow, hash);
824 if (head != cls_match) {
825 list_remove(&cls_match->list);
826 } else if (list_is_empty(&cls_match->list)) {
827 cmap_remove(&subtable->rules, &cls_match->cmap_node, hash);
829 struct cls_match *next = CONTAINER_OF(cls_match->list.next,
830 struct cls_match, list);
832 list_remove(&cls_match->list);
833 cmap_replace(&subtable->rules, &cls_match->cmap_node,
834 &next->cmap_node, hash);
837 partition = cls_match->partition;
839 tag_tracker_subtract(&partition->tracker, &partition->tags,
841 if (!partition->tags) {
842 cmap_remove(&cls->partitions, &partition->cmap_node,
843 hash_metadata(partition->metadata));
844 ovsrcu_postpone(free, partition);
848 if (--subtable->n_rules == 0) {
849 destroy_subtable(cls, subtable);
850 } else if (subtable->max_priority == cls_match->priority
851 && --subtable->max_count == 0) {
852 /* Find the new 'max_priority' and 'max_count'. */
853 struct cls_match *head;
854 unsigned int max_priority = 0;
856 CMAP_FOR_EACH (head, cmap_node, &subtable->rules) {
857 if (head->priority > max_priority) {
858 max_priority = head->priority;
859 subtable->max_count = 1;
860 } else if (head->priority == max_priority) {
861 ++subtable->max_count;
864 subtable->max_priority = max_priority;
865 pvector_change_priority(&cls->subtables, subtable, max_priority);
870 ovsrcu_postpone(free, cls_match);
871 rule->cls_match = NULL;
873 ovs_mutex_unlock(&cls->mutex);
878 /* Prefix tree context. Valid when 'lookup_done' is true. Can skip all
879 * subtables which have a prefix match on the trie field, but whose prefix
880 * length is not indicated in 'match_plens'. For example, a subtable that
881 * has a 8-bit trie field prefix match can be skipped if
882 * !be_get_bit_at(&match_plens, 8 - 1). If skipped, 'maskbits' prefix bits
883 * must be unwildcarded to make datapath flow only match packets it should. */
885 const struct cls_trie *trie;
886 bool lookup_done; /* Status of the lookup. */
887 uint8_t be32ofs; /* U32 offset of the field in question. */
888 unsigned int maskbits; /* Prefix length needed to avoid false matches. */
889 union mf_value match_plens; /* Bitmask of prefix lengths with possible
894 trie_ctx_init(struct trie_ctx *ctx, const struct cls_trie *trie)
897 ctx->be32ofs = trie->field->flow_be32ofs;
898 ctx->lookup_done = false;
901 /* Finds and returns the highest-priority rule in 'cls' that matches 'flow'.
902 * Returns a null pointer if no rules in 'cls' match 'flow'. If multiple rules
903 * of equal priority match 'flow', returns one arbitrarily.
905 * If a rule is found and 'wc' is non-null, bitwise-OR's 'wc' with the
906 * set of bits that were significant in the lookup. At some point
907 * earlier, 'wc' should have been initialized (e.g., by
908 * flow_wildcards_init_catchall()). */
910 classifier_lookup(const struct classifier *cls, const struct flow *flow,
911 struct flow_wildcards *wc)
913 const struct cls_partition *partition;
915 int64_t best_priority = -1;
916 const struct cls_match *best;
917 struct trie_ctx trie_ctx[CLS_MAX_TRIES];
918 struct cls_subtable *subtable;
920 /* Synchronize for cls->n_tries and subtable->trie_plen. They can change
921 * when table configuration changes, which happens typically only on
923 atomic_thread_fence(memory_order_acquire);
925 /* Determine 'tags' such that, if 'subtable->tag' doesn't intersect them,
926 * then 'flow' cannot possibly match in 'subtable':
928 * - If flow->metadata maps to a given 'partition', then we can use
929 * 'tags' for 'partition->tags'.
931 * - If flow->metadata has no partition, then no rule in 'cls' has an
932 * exact-match for flow->metadata. That means that we don't need to
933 * search any subtable that includes flow->metadata in its mask.
935 * In either case, we always need to search any cls_subtables that do not
936 * include flow->metadata in its mask. One way to do that would be to
937 * check the "cls_subtable"s explicitly for that, but that would require an
938 * extra branch per subtable. Instead, we mark such a cls_subtable's
939 * 'tags' as TAG_ALL and make sure that 'tags' is never empty. This means
940 * that 'tags' always intersects such a cls_subtable's 'tags', so we don't
941 * need a special case.
943 partition = (cmap_is_empty(&cls->partitions)
945 : find_partition(cls, flow->metadata,
946 hash_metadata(flow->metadata)));
947 tags = partition ? partition->tags : TAG_ARBITRARY;
949 /* Initialize trie contexts for match_find_wc(). */
950 for (int i = 0; i < cls->n_tries; i++) {
951 trie_ctx_init(&trie_ctx[i], &cls->tries[i]);
955 PVECTOR_FOR_EACH_PRIORITY(subtable, best_priority, 2,
956 sizeof(struct cls_subtable), &cls->subtables) {
957 struct cls_match *rule;
959 if (!tag_intersects(tags, subtable->tag)) {
963 rule = find_match_wc(subtable, flow, trie_ctx, cls->n_tries, wc);
964 if (rule && (int64_t)rule->priority > best_priority) {
965 best_priority = (int64_t)rule->priority;
970 return best ? best->cls_rule : NULL;
973 /* Finds and returns a rule in 'cls' with exactly the same priority and
974 * matching criteria as 'target'. Returns a null pointer if 'cls' doesn't
975 * contain an exact match. */
977 classifier_find_rule_exactly(const struct classifier *cls,
978 const struct cls_rule *target)
979 OVS_EXCLUDED(cls->mutex)
981 struct cls_match *head, *rule;
982 struct cls_subtable *subtable;
984 ovs_mutex_lock(&cls->mutex);
985 subtable = find_subtable(cls, &target->match.mask);
990 /* Skip if there is no hope. */
991 if (target->priority > subtable->max_priority) {
995 head = find_equal(subtable, &target->match.flow,
996 miniflow_hash_in_minimask(&target->match.flow,
997 &target->match.mask, 0));
998 FOR_EACH_RULE_IN_LIST (rule, head) {
999 if (target->priority >= rule->priority) {
1000 ovs_mutex_unlock(&cls->mutex);
1001 return target->priority == rule->priority ? rule->cls_rule : NULL;
1005 ovs_mutex_unlock(&cls->mutex);
1009 /* Finds and returns a rule in 'cls' with priority 'priority' and exactly the
1010 * same matching criteria as 'target'. Returns a null pointer if 'cls' doesn't
1011 * contain an exact match. */
1013 classifier_find_match_exactly(const struct classifier *cls,
1014 const struct match *target,
1015 unsigned int priority)
1017 struct cls_rule *retval;
1020 cls_rule_init(&cr, target, priority);
1021 retval = classifier_find_rule_exactly(cls, &cr);
1022 cls_rule_destroy(&cr);
1027 /* Checks if 'target' would overlap any other rule in 'cls'. Two rules are
1028 * considered to overlap if both rules have the same priority and a packet
1029 * could match both. */
1031 classifier_rule_overlaps(const struct classifier *cls,
1032 const struct cls_rule *target)
1033 OVS_EXCLUDED(cls->mutex)
1035 struct cls_subtable *subtable;
1036 int64_t stop_at_priority = (int64_t)target->priority - 1;
1038 ovs_mutex_lock(&cls->mutex);
1039 /* Iterate subtables in the descending max priority order. */
1040 PVECTOR_FOR_EACH_PRIORITY (subtable, stop_at_priority, 2,
1041 sizeof(struct cls_subtable), &cls->subtables) {
1042 uint32_t storage[FLOW_U32S];
1043 struct minimask mask;
1044 struct cls_match *head;
1046 minimask_combine(&mask, &target->match.mask, &subtable->mask, storage);
1047 CMAP_FOR_EACH (head, cmap_node, &subtable->rules) {
1048 struct cls_match *rule;
1050 FOR_EACH_RULE_IN_LIST (rule, head) {
1051 if (rule->priority < target->priority) {
1052 break; /* Rules in descending priority order. */
1054 if (rule->priority == target->priority
1055 && miniflow_equal_in_minimask(&target->match.flow,
1056 &rule->flow, &mask)) {
1057 ovs_mutex_unlock(&cls->mutex);
1064 ovs_mutex_unlock(&cls->mutex);
1068 /* Returns true if 'rule' exactly matches 'criteria' or if 'rule' is more
1069 * specific than 'criteria'. That is, 'rule' matches 'criteria' and this
1070 * function returns true if, for every field:
1072 * - 'criteria' and 'rule' specify the same (non-wildcarded) value for the
1075 * - 'criteria' wildcards the field,
1077 * Conversely, 'rule' does not match 'criteria' and this function returns false
1078 * if, for at least one field:
1080 * - 'criteria' and 'rule' specify different values for the field, or
1082 * - 'criteria' specifies a value for the field but 'rule' wildcards it.
1084 * Equivalently, the truth table for whether a field matches is:
1089 * r +---------+---------+
1090 * i wild | yes | yes |
1092 * e +---------+---------+
1093 * r exact | no |if values|
1095 * a +---------+---------+
1097 * This is the matching rule used by OpenFlow 1.0 non-strict OFPT_FLOW_MOD
1098 * commands and by OpenFlow 1.0 aggregate and flow stats.
1100 * Ignores rule->priority. */
1102 cls_rule_is_loose_match(const struct cls_rule *rule,
1103 const struct minimatch *criteria)
1105 return (!minimask_has_extra(&rule->match.mask, &criteria->mask)
1106 && miniflow_equal_in_minimask(&rule->match.flow, &criteria->flow,
1113 rule_matches(const struct cls_match *rule, const struct cls_rule *target)
1116 || miniflow_equal_in_minimask(&rule->flow,
1117 &target->match.flow,
1118 &target->match.mask));
1121 static struct cls_match *
1122 search_subtable(const struct cls_subtable *subtable,
1123 struct cls_cursor *cursor)
1126 || !minimask_has_extra(&subtable->mask, &cursor->target->match.mask)) {
1127 struct cls_match *rule;
1129 CMAP_CURSOR_FOR_EACH (rule, cmap_node, &cursor->rules,
1131 if (rule_matches(rule, cursor->target)) {
1139 /* Initializes 'cursor' for iterating through rules in 'cls', and returns the
1140 * first matching cls_rule via '*pnode', or NULL if there are no matches.
1142 * - If 'target' is null, the cursor will visit every rule in 'cls'.
1144 * - If 'target' is nonnull, the cursor will visit each 'rule' in 'cls'
1145 * such that cls_rule_is_loose_match(rule, target) returns true.
1147 * Ignores target->priority. */
1148 struct cls_cursor cls_cursor_start(const struct classifier *cls,
1149 const struct cls_rule *target,
1151 OVS_NO_THREAD_SAFETY_ANALYSIS
1153 struct cls_cursor cursor;
1154 struct cls_subtable *subtable;
1158 cursor.target = target && !cls_rule_is_catchall(target) ? target : NULL;
1161 /* Find first rule. */
1162 ovs_mutex_lock(&cursor.cls->mutex);
1163 CMAP_CURSOR_FOR_EACH (subtable, cmap_node, &cursor.subtables,
1164 &cursor.cls->subtables_map) {
1165 struct cls_match *rule = search_subtable(subtable, &cursor);
1168 cursor.subtable = subtable;
1169 cursor.rule = rule->cls_rule;
1174 /* Leave locked if requested and have a rule. */
1175 if (safe || !cursor.rule) {
1176 ovs_mutex_unlock(&cursor.cls->mutex);
1181 static struct cls_rule *
1182 cls_cursor_next(struct cls_cursor *cursor)
1183 OVS_NO_THREAD_SAFETY_ANALYSIS
1185 struct cls_match *rule = cursor->rule->cls_match;
1186 const struct cls_subtable *subtable;
1187 struct cls_match *next;
1189 next = next_rule_in_list__(rule);
1190 if (next->priority < rule->priority) {
1191 return next->cls_rule;
1194 /* 'next' is the head of the list, that is, the rule that is included in
1195 * the subtable's map. (This is important when the classifier contains
1196 * rules that differ only in priority.) */
1198 CMAP_CURSOR_FOR_EACH_CONTINUE (rule, cmap_node, &cursor->rules) {
1199 if (rule_matches(rule, cursor->target)) {
1200 return rule->cls_rule;
1204 subtable = cursor->subtable;
1205 CMAP_CURSOR_FOR_EACH_CONTINUE (subtable, cmap_node, &cursor->subtables) {
1206 rule = search_subtable(subtable, cursor);
1208 cursor->subtable = subtable;
1209 return rule->cls_rule;
1216 /* Sets 'cursor->rule' to the next matching cls_rule in 'cursor''s iteration,
1217 * or to null if all matching rules have been visited. */
1219 cls_cursor_advance(struct cls_cursor *cursor)
1220 OVS_NO_THREAD_SAFETY_ANALYSIS
1223 ovs_mutex_lock(&cursor->cls->mutex);
1225 cursor->rule = cls_cursor_next(cursor);
1226 if (cursor->safe || !cursor->rule) {
1227 ovs_mutex_unlock(&cursor->cls->mutex);
1231 static struct cls_subtable *
1232 find_subtable(const struct classifier *cls, const struct minimask *mask)
1233 OVS_REQUIRES(cls->mutex)
1235 struct cls_subtable *subtable;
1237 CMAP_FOR_EACH_WITH_HASH (subtable, cmap_node, minimask_hash(mask, 0),
1238 &cls->subtables_map) {
1239 if (minimask_equal(mask, &subtable->mask)) {
1246 /* The new subtable will be visible to the readers only after this. */
1247 static struct cls_subtable *
1248 insert_subtable(struct classifier *cls, const struct minimask *mask)
1249 OVS_REQUIRES(cls->mutex)
1251 uint32_t hash = minimask_hash(mask, 0);
1252 struct cls_subtable *subtable;
1254 struct flow_wildcards old, new;
1256 int count = count_1bits(mask->masks.map);
1258 subtable = xzalloc(sizeof *subtable - sizeof mask->masks.inline_values
1259 + MINIFLOW_VALUES_SIZE(count));
1260 cmap_init(&subtable->rules);
1261 miniflow_clone_inline(&subtable->mask.masks, &mask->masks, count);
1263 /* Init indices for segmented lookup, if any. */
1264 flow_wildcards_init_catchall(&new);
1267 for (i = 0; i < cls->n_flow_segments; i++) {
1268 flow_wildcards_fold_minimask_range(&new, mask, prev,
1269 cls->flow_segments[i]);
1270 /* Add an index if it adds mask bits. */
1271 if (!flow_wildcards_equal(&new, &old)) {
1272 cmap_init(&subtable->indices[index]);
1273 subtable->index_ofs[index] = cls->flow_segments[i];
1277 prev = cls->flow_segments[i];
1279 /* Check if the rest of the subtable's mask adds any bits,
1280 * and remove the last index if it doesn't. */
1282 flow_wildcards_fold_minimask_range(&new, mask, prev, FLOW_U32S);
1283 if (flow_wildcards_equal(&new, &old)) {
1285 subtable->index_ofs[index] = 0;
1286 cmap_destroy(&subtable->indices[index]);
1289 subtable->n_indices = index;
1291 subtable->tag = (minimask_get_metadata_mask(mask) == OVS_BE64_MAX
1292 ? tag_create_deterministic(hash)
1295 for (i = 0; i < cls->n_tries; i++) {
1296 subtable->trie_plen[i] = minimask_get_prefix_len(mask,
1297 cls->tries[i].field);
1301 ovsrcu_set_hidden(&subtable->ports_trie, NULL);
1302 subtable->ports_mask_len
1303 = 32 - ctz32(ntohl(MINIFLOW_GET_BE32(&mask->masks, tp_src)));
1305 cmap_insert(&cls->subtables_map, &subtable->cmap_node, hash);
1311 destroy_subtable(struct classifier *cls, struct cls_subtable *subtable)
1312 OVS_REQUIRES(cls->mutex)
1316 pvector_remove(&cls->subtables, subtable);
1317 trie_destroy(&subtable->ports_trie);
1319 for (i = 0; i < subtable->n_indices; i++) {
1320 cmap_destroy(&subtable->indices[i]);
1322 cmap_remove(&cls->subtables_map, &subtable->cmap_node,
1323 minimask_hash(&subtable->mask, 0));
1324 minimask_destroy(&subtable->mask);
1325 cmap_destroy(&subtable->rules);
1326 ovsrcu_postpone(free, subtable);
1334 static unsigned int be_get_bit_at(const ovs_be32 value[], unsigned int ofs);
1336 /* Return 'true' if can skip rest of the subtable based on the prefix trie
1337 * lookup results. */
1339 check_tries(struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries,
1340 const unsigned int field_plen[CLS_MAX_TRIES],
1341 const struct range ofs, const struct flow *flow,
1342 struct flow_wildcards *wc)
1346 /* Check if we could avoid fully unwildcarding the next level of
1347 * fields using the prefix tries. The trie checks are done only as
1348 * needed to avoid folding in additional bits to the wildcards mask. */
1349 for (j = 0; j < n_tries; j++) {
1350 /* Is the trie field relevant for this subtable? */
1351 if (field_plen[j]) {
1352 struct trie_ctx *ctx = &trie_ctx[j];
1353 uint8_t be32ofs = ctx->be32ofs;
1355 /* Is the trie field within the current range of fields? */
1356 if (be32ofs >= ofs.start && be32ofs < ofs.end) {
1357 /* On-demand trie lookup. */
1358 if (!ctx->lookup_done) {
1359 memset(&ctx->match_plens, 0, sizeof ctx->match_plens);
1360 ctx->maskbits = trie_lookup(ctx->trie, flow,
1362 ctx->lookup_done = true;
1364 /* Possible to skip the rest of the subtable if subtable's
1365 * prefix on the field is not included in the lookup result. */
1366 if (!be_get_bit_at(&ctx->match_plens.be32, field_plen[j] - 1)) {
1367 /* We want the trie lookup to never result in unwildcarding
1368 * any bits that would not be unwildcarded otherwise.
1369 * Since the trie is shared by the whole classifier, it is
1370 * possible that the 'maskbits' contain bits that are
1371 * irrelevant for the partition relevant for the current
1372 * packet. Hence the checks below. */
1374 /* Check that the trie result will not unwildcard more bits
1375 * than this subtable would otherwise. */
1376 if (ctx->maskbits <= field_plen[j]) {
1377 /* Unwildcard the bits and skip the rest. */
1378 mask_set_prefix_bits(wc, be32ofs, ctx->maskbits);
1379 /* Note: Prerequisite already unwildcarded, as the only
1380 * prerequisite of the supported trie lookup fields is
1381 * the ethertype, which is always unwildcarded. */
1384 /* Can skip if the field is already unwildcarded. */
1385 if (mask_prefix_bits_set(wc, be32ofs, ctx->maskbits)) {
1395 /* Returns true if 'target' satisifies 'flow'/'mask', that is, if each bit
1396 * for which 'flow', for which 'mask' has a bit set, specifies a particular
1397 * value has the correct value in 'target'.
1399 * This function is equivalent to miniflow_equal_flow_in_minimask(flow,
1400 * target, mask) but this is faster because of the invariant that
1401 * flow->map and mask->masks.map are the same, and that this version
1402 * takes the 'wc'. */
1404 miniflow_and_mask_matches_flow(const struct miniflow *flow,
1405 const struct minimask *mask,
1406 const struct flow *target)
1408 const uint32_t *flowp = miniflow_get_u32_values(flow);
1409 const uint32_t *maskp = miniflow_get_u32_values(&mask->masks);
1412 MAP_FOR_EACH_INDEX(idx, mask->masks.map) {
1413 uint32_t diff = (*flowp++ ^ flow_u32_value(target, idx)) & *maskp++;
1423 static inline struct cls_match *
1424 find_match(const struct cls_subtable *subtable, const struct flow *flow,
1427 struct cls_match *rule;
1429 CMAP_FOR_EACH_WITH_HASH (rule, cmap_node, hash, &subtable->rules) {
1430 if (miniflow_and_mask_matches_flow(&rule->flow, &subtable->mask,
1439 /* Returns true if 'target' satisifies 'flow'/'mask', that is, if each bit
1440 * for which 'flow', for which 'mask' has a bit set, specifies a particular
1441 * value has the correct value in 'target'.
1443 * This function is equivalent to miniflow_and_mask_matches_flow() but this
1444 * version fills in the mask bits in 'wc'. */
1446 miniflow_and_mask_matches_flow_wc(const struct miniflow *flow,
1447 const struct minimask *mask,
1448 const struct flow *target,
1449 struct flow_wildcards *wc)
1451 const uint32_t *flowp = miniflow_get_u32_values(flow);
1452 const uint32_t *maskp = miniflow_get_u32_values(&mask->masks);
1455 MAP_FOR_EACH_INDEX(idx, mask->masks.map) {
1456 uint32_t mask = *maskp++;
1457 uint32_t diff = (*flowp++ ^ flow_u32_value(target, idx)) & mask;
1460 /* Only unwildcard if none of the differing bits is already
1462 if (!(flow_u32_value(&wc->masks, idx) & diff)) {
1463 /* Keep one bit of the difference. */
1464 *flow_u32_lvalue(&wc->masks, idx) |= rightmost_1bit(diff);
1468 /* Fill in the bits that were looked at. */
1469 *flow_u32_lvalue(&wc->masks, idx) |= mask;
1475 /* Unwildcard the fields looked up so far, if any. */
1477 fill_range_wc(const struct cls_subtable *subtable, struct flow_wildcards *wc,
1481 flow_wildcards_fold_minimask_range(wc, &subtable->mask, 0, to);
1485 static struct cls_match *
1486 find_match_wc(const struct cls_subtable *subtable, const struct flow *flow,
1487 struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries,
1488 struct flow_wildcards *wc)
1490 uint32_t basis = 0, hash;
1491 struct cls_match *rule = NULL;
1495 if (OVS_UNLIKELY(!wc)) {
1496 return find_match(subtable, flow,
1497 flow_hash_in_minimask(flow, &subtable->mask, 0));
1501 /* Try to finish early by checking fields in segments. */
1502 for (i = 0; i < subtable->n_indices; i++) {
1503 const struct cmap_node *inode;
1505 ofs.end = subtable->index_ofs[i];
1507 if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow,
1509 /* 'wc' bits for the trie field set, now unwildcard the preceding
1510 * bits used so far. */
1511 fill_range_wc(subtable, wc, ofs.start);
1514 hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
1516 inode = cmap_find(&subtable->indices[i], hash);
1518 /* No match, can stop immediately, but must fold in the bits
1519 * used in lookup so far. */
1520 fill_range_wc(subtable, wc, ofs.end);
1524 /* If we have narrowed down to a single rule already, check whether
1525 * that rule matches. Either way, we're done.
1527 * (Rare) hash collisions may cause us to miss the opportunity for this
1529 if (!cmap_node_next(inode)) {
1530 ASSIGN_CONTAINER(rule, inode - i, index_nodes);
1531 if (miniflow_and_mask_matches_flow_wc(&rule->flow, &subtable->mask,
1537 ofs.start = ofs.end;
1539 ofs.end = FLOW_U32S;
1540 /* Trie check for the final range. */
1541 if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow, wc)) {
1542 fill_range_wc(subtable, wc, ofs.start);
1545 hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
1547 rule = find_match(subtable, flow, hash);
1548 if (!rule && subtable->ports_mask_len) {
1549 /* Ports are always part of the final range, if any.
1550 * No match was found for the ports. Use the ports trie to figure out
1551 * which ports bits to unwildcard. */
1553 ovs_be32 value, plens, mask;
1555 mask = MINIFLOW_GET_BE32(&subtable->mask.masks, tp_src);
1556 value = ((OVS_FORCE ovs_be32 *)flow)[TP_PORTS_OFS32] & mask;
1557 mbits = trie_lookup_value(&subtable->ports_trie, &value, &plens, 32);
1559 ((OVS_FORCE ovs_be32 *)&wc->masks)[TP_PORTS_OFS32] |=
1560 mask & htonl(~0 << (32 - mbits));
1562 /* Unwildcard all bits in the mask upto the ports, as they were used
1563 * to determine there is no match. */
1564 fill_range_wc(subtable, wc, TP_PORTS_OFS32);
1568 /* Must unwildcard all the fields, as they were looked at. */
1569 flow_wildcards_fold_minimask(wc, &subtable->mask);
1573 static struct cls_match *
1574 find_equal(struct cls_subtable *subtable, const struct miniflow *flow,
1577 struct cls_match *head;
1579 CMAP_FOR_EACH_WITH_HASH (head, cmap_node, hash, &subtable->rules) {
1580 if (miniflow_equal(&head->flow, flow)) {
1588 * As the readers are operating concurrently with the modifications, a
1589 * concurrent reader may or may not see the new rule, depending on how
1590 * the concurrent events overlap with each other. This is no
1591 * different from the former locked behavior, but there the visibility
1592 * of the new rule only depended on the timing of the locking
1595 * The new rule is first added to the segment indices, so the readers
1596 * may find the rule in the indices before the rule is visible in the
1597 * subtables 'rules' map. This may result in us losing the
1598 * opportunity to quit lookups earlier, resulting in sub-optimal
1599 * wildcarding. This will be fixed by forthcoming revalidation always
1600 * scheduled after flow table changes.
1602 * Similar behavior may happen due to us removing the overlapping rule
1603 * (if any) from the indices only after the new rule has been added.
1605 * The subtable's max priority is updated only after the rule is
1606 * inserted, so the concurrent readers may not see the rule, as the
1607 * updated priority ordered subtable list will only be visible after
1608 * the subtable's max priority is updated.
1610 * Similarly, the classifier's partitions for new rules are updated by
1611 * the caller after this function, so the readers may keep skipping
1612 * the subtable until they see the updated partitions.
1614 static struct cls_match *
1615 insert_rule(struct classifier *cls, struct cls_subtable *subtable,
1616 struct cls_rule *new_rule)
1617 OVS_REQUIRES(cls->mutex)
1619 struct cls_match *old = NULL;
1620 struct cls_match *new = cls_match_alloc(new_rule);
1621 struct cls_match *head;
1623 uint32_t basis = 0, hash, ihash[CLS_MAX_INDICES];
1624 uint8_t prev_be32ofs = 0;
1626 /* Add new node to segment indices. */
1627 for (i = 0; i < subtable->n_indices; i++) {
1628 ihash[i] = minimatch_hash_range(&new_rule->match, prev_be32ofs,
1629 subtable->index_ofs[i], &basis);
1630 cmap_insert(&subtable->indices[i], &new->index_nodes[i], ihash[i]);
1631 prev_be32ofs = subtable->index_ofs[i];
1633 hash = minimatch_hash_range(&new_rule->match, prev_be32ofs, FLOW_U32S,
1635 head = find_equal(subtable, &new_rule->match.flow, hash);
1637 cmap_insert(&subtable->rules, &new->cmap_node, hash);
1638 list_init(&new->list);
1641 /* Scan the list for the insertion point that will keep the list in
1642 * order of decreasing priority. */
1643 struct cls_match *rule;
1645 FOR_EACH_RULE_IN_LIST (rule, head) {
1646 if (new->priority >= rule->priority) {
1648 /* 'new' is the new highest-priority flow in the list. */
1649 cmap_replace(&subtable->rules, &rule->cmap_node,
1650 &new->cmap_node, hash);
1653 if (new->priority == rule->priority) {
1654 list_replace(&new->list, &rule->list);
1657 list_insert(&rule->list, &new->list);
1663 /* Insert 'new' at the end of the list. */
1664 list_push_back(&head->list, &new->list);
1669 subtable->n_rules++;
1671 /* Rule was added, not replaced. Update 'subtable's 'max_priority'
1672 * and 'max_count', if necessary. */
1673 if (subtable->n_rules == 1) {
1674 subtable->max_priority = new->priority;
1675 subtable->max_count = 1;
1676 pvector_insert(&cls->subtables, subtable, new->priority);
1677 } else if (subtable->max_priority == new->priority) {
1678 ++subtable->max_count;
1679 } else if (new->priority > subtable->max_priority) {
1680 subtable->max_priority = new->priority;
1681 subtable->max_count = 1;
1682 pvector_change_priority(&cls->subtables, subtable, new->priority);
1685 /* Remove old node from indices. */
1686 for (i = 0; i < subtable->n_indices; i++) {
1687 cmap_remove(&subtable->indices[i], &old->index_nodes[i], ihash[i]);
1693 static struct cls_match *
1694 next_rule_in_list__(struct cls_match *rule)
1695 OVS_NO_THREAD_SAFETY_ANALYSIS
1697 struct cls_match *next = NULL;
1698 next = OBJECT_CONTAINING(rule->list.next, next, list);
1702 static struct cls_match *
1703 next_rule_in_list(struct cls_match *rule)
1705 struct cls_match *next = next_rule_in_list__(rule);
1706 return next->priority < rule->priority ? next : NULL;
1709 /* A longest-prefix match tree. */
1711 uint32_t prefix; /* Prefix bits for this node, MSB first. */
1712 uint8_t n_bits; /* Never zero, except for the root node. */
1713 unsigned int n_rules; /* Number of rules that have this prefix. */
1714 rcu_trie_ptr edges[2]; /* Both NULL if leaf. */
1717 /* Max bits per node. Must fit in struct trie_node's 'prefix'.
1718 * Also tested with 16, 8, and 5 to stress the implementation. */
1719 #define TRIE_PREFIX_BITS 32
1721 /* Return at least 'plen' bits of the 'prefix', starting at bit offset 'ofs'.
1722 * Prefixes are in the network byte order, and the offset 0 corresponds to
1723 * the most significant bit of the first byte. The offset can be read as
1724 * "how many bits to skip from the start of the prefix starting at 'pr'". */
1726 raw_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
1730 pr += ofs / 32; /* Where to start. */
1731 ofs %= 32; /* How many bits to skip at 'pr'. */
1733 prefix = ntohl(*pr) << ofs; /* Get the first 32 - ofs bits. */
1734 if (plen > 32 - ofs) { /* Need more than we have already? */
1735 prefix |= ntohl(*++pr) >> (32 - ofs);
1737 /* Return with possible unwanted bits at the end. */
1741 /* Return min(TRIE_PREFIX_BITS, plen) bits of the 'prefix', starting at bit
1742 * offset 'ofs'. Prefixes are in the network byte order, and the offset 0
1743 * corresponds to the most significant bit of the first byte. The offset can
1744 * be read as "how many bits to skip from the start of the prefix starting at
1747 trie_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
1752 if (plen > TRIE_PREFIX_BITS) {
1753 plen = TRIE_PREFIX_BITS; /* Get at most TRIE_PREFIX_BITS. */
1755 /* Return with unwanted bits cleared. */
1756 return raw_get_prefix(pr, ofs, plen) & ~0u << (32 - plen);
1759 /* Return the number of equal bits in 'n_bits' of 'prefix's MSBs and a 'value'
1760 * starting at "MSB 0"-based offset 'ofs'. */
1762 prefix_equal_bits(uint32_t prefix, unsigned int n_bits, const ovs_be32 value[],
1765 uint64_t diff = prefix ^ raw_get_prefix(value, ofs, n_bits);
1766 /* Set the bit after the relevant bits to limit the result. */
1767 return raw_clz64(diff << 32 | UINT64_C(1) << (63 - n_bits));
1770 /* Return the number of equal bits in 'node' prefix and a 'prefix' of length
1771 * 'plen', starting at "MSB 0"-based offset 'ofs'. */
1773 trie_prefix_equal_bits(const struct trie_node *node, const ovs_be32 prefix[],
1774 unsigned int ofs, unsigned int plen)
1776 return prefix_equal_bits(node->prefix, MIN(node->n_bits, plen - ofs),
1780 /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' can
1781 * be greater than 31. */
1783 be_get_bit_at(const ovs_be32 value[], unsigned int ofs)
1785 return (((const uint8_t *)value)[ofs / 8] >> (7 - ofs % 8)) & 1u;
1788 /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' must
1789 * be between 0 and 31, inclusive. */
1791 get_bit_at(const uint32_t prefix, unsigned int ofs)
1793 return (prefix >> (31 - ofs)) & 1u;
1796 /* Create new branch. */
1797 static struct trie_node *
1798 trie_branch_create(const ovs_be32 *prefix, unsigned int ofs, unsigned int plen,
1799 unsigned int n_rules)
1801 struct trie_node *node = xmalloc(sizeof *node);
1803 node->prefix = trie_get_prefix(prefix, ofs, plen);
1805 if (plen <= TRIE_PREFIX_BITS) {
1806 node->n_bits = plen;
1807 ovsrcu_set_hidden(&node->edges[0], NULL);
1808 ovsrcu_set_hidden(&node->edges[1], NULL);
1809 node->n_rules = n_rules;
1810 } else { /* Need intermediate nodes. */
1811 struct trie_node *subnode = trie_branch_create(prefix,
1812 ofs + TRIE_PREFIX_BITS,
1813 plen - TRIE_PREFIX_BITS,
1815 int bit = get_bit_at(subnode->prefix, 0);
1816 node->n_bits = TRIE_PREFIX_BITS;
1817 ovsrcu_set_hidden(&node->edges[bit], subnode);
1818 ovsrcu_set_hidden(&node->edges[!bit], NULL);
1825 trie_node_destroy(const struct trie_node *node)
1827 ovsrcu_postpone(free, CONST_CAST(struct trie_node *, node));
1830 /* Copy a trie node for modification and postpone delete the old one. */
1831 static struct trie_node *
1832 trie_node_rcu_realloc(const struct trie_node *node)
1834 struct trie_node *new_node = xmalloc(sizeof *node);
1837 trie_node_destroy(node);
1842 /* May only be called while holding the classifier mutex. */
1844 trie_destroy(rcu_trie_ptr *trie)
1846 struct trie_node *node = ovsrcu_get_protected(struct trie_node *, trie);
1849 ovsrcu_set_hidden(trie, NULL);
1850 trie_destroy(&node->edges[0]);
1851 trie_destroy(&node->edges[1]);
1852 trie_node_destroy(node);
1857 trie_is_leaf(const struct trie_node *trie)
1860 return !ovsrcu_get(struct trie_node *, &trie->edges[0])
1861 && !ovsrcu_get(struct trie_node *, &trie->edges[1]);
1865 mask_set_prefix_bits(struct flow_wildcards *wc, uint8_t be32ofs,
1866 unsigned int n_bits)
1868 ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
1871 for (i = 0; i < n_bits / 32; i++) {
1872 mask[i] = OVS_BE32_MAX;
1875 mask[i] |= htonl(~0u << (32 - n_bits % 32));
1880 mask_prefix_bits_set(const struct flow_wildcards *wc, uint8_t be32ofs,
1881 unsigned int n_bits)
1883 ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
1885 ovs_be32 zeroes = 0;
1887 for (i = 0; i < n_bits / 32; i++) {
1891 zeroes |= ~mask[i] & htonl(~0u << (32 - n_bits % 32));
1894 return !zeroes; /* All 'n_bits' bits set. */
1897 static rcu_trie_ptr *
1898 trie_next_edge(struct trie_node *node, const ovs_be32 value[],
1901 return node->edges + be_get_bit_at(value, ofs);
1904 static const struct trie_node *
1905 trie_next_node(const struct trie_node *node, const ovs_be32 value[],
1908 return ovsrcu_get(struct trie_node *,
1909 &node->edges[be_get_bit_at(value, ofs)]);
1912 /* Set the bit at ("MSB 0"-based) offset 'ofs'. 'ofs' can be greater than 31.
1915 be_set_bit_at(ovs_be32 value[], unsigned int ofs)
1917 ((uint8_t *)value)[ofs / 8] |= 1u << (7 - ofs % 8);
1920 /* Returns the number of bits in the prefix mask necessary to determine a
1921 * mismatch, in case there are longer prefixes in the tree below the one that
1923 * '*plens' will have a bit set for each prefix length that may have matching
1924 * rules. The caller is responsible for clearing the '*plens' prior to
1928 trie_lookup_value(const rcu_trie_ptr *trie, const ovs_be32 value[],
1929 ovs_be32 plens[], unsigned int n_bits)
1931 const struct trie_node *prev = NULL;
1932 const struct trie_node *node = ovsrcu_get(struct trie_node *, trie);
1933 unsigned int match_len = 0; /* Number of matching bits. */
1935 for (; node; prev = node, node = trie_next_node(node, value, match_len)) {
1936 unsigned int eqbits;
1937 /* Check if this edge can be followed. */
1938 eqbits = prefix_equal_bits(node->prefix, node->n_bits, value,
1940 match_len += eqbits;
1941 if (eqbits < node->n_bits) { /* Mismatch, nothing more to be found. */
1942 /* Bit at offset 'match_len' differed. */
1943 return match_len + 1; /* Includes the first mismatching bit. */
1945 /* Full match, check if rules exist at this prefix length. */
1946 if (node->n_rules > 0) {
1947 be_set_bit_at(plens, match_len - 1);
1949 if (match_len >= n_bits) {
1950 return n_bits; /* Full prefix. */
1953 /* node == NULL. Full match so far, but we tried to follow an
1954 * non-existing branch. Need to exclude the other branch if it exists
1955 * (it does not if we were called on an empty trie or 'prev' is a leaf
1957 return !prev || trie_is_leaf(prev) ? match_len : match_len + 1;
1961 trie_lookup(const struct cls_trie *trie, const struct flow *flow,
1962 union mf_value *plens)
1964 const struct mf_field *mf = trie->field;
1966 /* Check that current flow matches the prerequisites for the trie
1967 * field. Some match fields are used for multiple purposes, so we
1968 * must check that the trie is relevant for this flow. */
1969 if (mf_are_prereqs_ok(mf, flow)) {
1970 return trie_lookup_value(&trie->root,
1971 &((ovs_be32 *)flow)[mf->flow_be32ofs],
1972 &plens->be32, mf->n_bits);
1974 memset(plens, 0xff, sizeof *plens); /* All prefixes, no skipping. */
1975 return 0; /* Value not used in this case. */
1978 /* Returns the length of a prefix match mask for the field 'mf' in 'minimask'.
1979 * Returns the u32 offset to the miniflow data in '*miniflow_index', if
1980 * 'miniflow_index' is not NULL. */
1982 minimask_get_prefix_len(const struct minimask *minimask,
1983 const struct mf_field *mf)
1985 unsigned int n_bits = 0, mask_tz = 0; /* Non-zero when end of mask seen. */
1986 uint8_t u32_ofs = mf->flow_be32ofs;
1987 uint8_t u32_end = u32_ofs + mf->n_bytes / 4;
1989 for (; u32_ofs < u32_end; ++u32_ofs) {
1991 mask = ntohl((OVS_FORCE ovs_be32)minimask_get(minimask, u32_ofs));
1993 /* Validate mask, count the mask length. */
1996 return 0; /* No bits allowed after mask ended. */
1999 if (~mask & (~mask + 1)) {
2000 return 0; /* Mask not contiguous. */
2002 mask_tz = ctz32(mask);
2003 n_bits += 32 - mask_tz;
2011 * This is called only when mask prefix is known to be CIDR and non-zero.
2012 * Relies on the fact that the flow and mask have the same map, and since
2013 * the mask is CIDR, the storage for the flow field exists even if it
2014 * happened to be zeros.
2016 static const ovs_be32 *
2017 minimatch_get_prefix(const struct minimatch *match, const struct mf_field *mf)
2019 return miniflow_get_be32_values(&match->flow) +
2020 count_1bits(match->flow.map & ((UINT64_C(1) << mf->flow_be32ofs) - 1));
2023 /* Insert rule in to the prefix tree.
2024 * 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2027 trie_insert(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
2029 trie_insert_prefix(&trie->root,
2030 minimatch_get_prefix(&rule->match, trie->field), mlen);
2034 trie_insert_prefix(rcu_trie_ptr *edge, const ovs_be32 *prefix, int mlen)
2036 struct trie_node *node;
2039 /* Walk the tree. */
2040 for (; (node = ovsrcu_get_protected(struct trie_node *, edge));
2041 edge = trie_next_edge(node, prefix, ofs)) {
2042 unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
2044 if (eqbits < node->n_bits) {
2045 /* Mismatch, new node needs to be inserted above. */
2046 int old_branch = get_bit_at(node->prefix, eqbits);
2047 struct trie_node *new_parent;
2049 new_parent = trie_branch_create(prefix, ofs - eqbits, eqbits,
2050 ofs == mlen ? 1 : 0);
2051 /* Copy the node to modify it. */
2052 node = trie_node_rcu_realloc(node);
2053 /* Adjust the new node for its new position in the tree. */
2054 node->prefix <<= eqbits;
2055 node->n_bits -= eqbits;
2056 ovsrcu_set_hidden(&new_parent->edges[old_branch], node);
2058 /* Check if need a new branch for the new rule. */
2060 ovsrcu_set_hidden(&new_parent->edges[!old_branch],
2061 trie_branch_create(prefix, ofs, mlen - ofs,
2064 ovsrcu_set(edge, new_parent); /* Publish changes. */
2067 /* Full match so far. */
2070 /* Full match at the current node, rule needs to be added here. */
2075 /* Must insert a new tree branch for the new rule. */
2076 ovsrcu_set(edge, trie_branch_create(prefix, ofs, mlen - ofs, 1));
2079 /* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2082 trie_remove(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
2084 trie_remove_prefix(&trie->root,
2085 minimatch_get_prefix(&rule->match, trie->field), mlen);
2088 /* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2091 trie_remove_prefix(rcu_trie_ptr *root, const ovs_be32 *prefix, int mlen)
2093 struct trie_node *node;
2094 rcu_trie_ptr *edges[sizeof(union mf_value) * 8];
2095 int depth = 0, ofs = 0;
2097 /* Walk the tree. */
2098 for (edges[0] = root;
2099 (node = ovsrcu_get_protected(struct trie_node *, edges[depth]));
2100 edges[++depth] = trie_next_edge(node, prefix, ofs)) {
2101 unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
2103 if (eqbits < node->n_bits) {
2104 /* Mismatch, nothing to be removed. This should never happen, as
2105 * only rules in the classifier are ever removed. */
2106 break; /* Log a warning. */
2108 /* Full match so far. */
2112 /* Full prefix match at the current node, remove rule here. */
2113 if (!node->n_rules) {
2114 break; /* Log a warning. */
2118 /* Check if can prune the tree. */
2119 while (!node->n_rules) {
2120 struct trie_node *next,
2121 *edge0 = ovsrcu_get_protected(struct trie_node *,
2123 *edge1 = ovsrcu_get_protected(struct trie_node *,
2126 if (edge0 && edge1) {
2127 break; /* A branching point, cannot prune. */
2130 /* Else have at most one child node, remove this node. */
2131 next = edge0 ? edge0 : edge1;
2134 if (node->n_bits + next->n_bits > TRIE_PREFIX_BITS) {
2135 break; /* Cannot combine. */
2137 next = trie_node_rcu_realloc(next); /* Modify. */
2139 /* Combine node with next. */
2140 next->prefix = node->prefix | next->prefix >> node->n_bits;
2141 next->n_bits += node->n_bits;
2143 /* Update the parent's edge. */
2144 ovsrcu_set(edges[depth], next); /* Publish changes. */
2145 trie_node_destroy(node);
2147 if (next || !depth) {
2148 /* Branch not pruned or at root, nothing more to do. */
2151 node = ovsrcu_get_protected(struct trie_node *,
2157 /* Cannot go deeper. This should never happen, since only rules
2158 * that actually exist in the classifier are ever removed. */
2159 VLOG_WARN("Trying to remove non-existing rule from a prefix trie.");