2 * Copyright (c) 2009, 2010, 2011, 2012, 2013 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"
27 #include "ovs-thread.h"
31 VLOG_DEFINE_THIS_MODULE(classifier);
36 /* Ports trie depends on both ports sharing the same ovs_be32. */
37 #define TP_PORTS_OFS32 (offsetof(struct flow, tp_src) / 4)
38 BUILD_ASSERT_DECL(TP_PORTS_OFS32 == offsetof(struct flow, tp_dst) / 4);
40 /* Prefix trie for a 'field' */
42 const struct mf_field *field; /* Trie field, or NULL. */
43 struct trie_node *root; /* NULL if none. */
46 struct cls_subtable_entry {
47 struct cls_subtable *subtable;
49 unsigned int max_priority;
52 struct cls_subtables {
53 size_t count; /* One past last valid array element. */
54 size_t alloc_size; /* Number of allocated elements. */
55 struct cls_subtable_entry *array;
59 CLS_MAX_INDICES = 3 /* Maximum number of lookup indices per subtable. */
62 struct cls_classifier {
63 int n_rules; /* Total number of rules. */
64 uint8_t n_flow_segments;
65 uint8_t flow_segments[CLS_MAX_INDICES]; /* Flow segment boundaries to use
66 * for staged lookup. */
67 struct hmap subtables_map; /* Contains "struct cls_subtable"s. */
68 struct cls_subtables subtables;
69 struct hmap partitions; /* Contains "struct cls_partition"s. */
70 struct cls_trie tries[CLS_MAX_TRIES]; /* Prefix tries. */
74 /* A set of rules that all have the same fields wildcarded. */
76 struct hmap_node hmap_node; /* Within struct cls_classifier 'subtables_map'
78 struct hmap rules; /* Contains "struct cls_rule"s. */
79 int n_rules; /* Number of rules, including duplicates. */
80 unsigned int max_priority; /* Max priority of any rule in the subtable. */
81 unsigned int max_count; /* Count of max_priority rules. */
82 tag_type tag; /* Tag generated from mask for partitioning. */
83 uint8_t n_indices; /* How many indices to use. */
84 uint8_t index_ofs[CLS_MAX_INDICES]; /* u32 flow segment boundaries. */
85 struct hindex indices[CLS_MAX_INDICES]; /* Staged lookup indices. */
86 unsigned int trie_plen[CLS_MAX_TRIES]; /* Trie prefix length in 'mask'. */
88 struct trie_node *ports_trie; /* NULL if none. */
89 struct minimask mask; /* Wildcards for fields. */
90 /* 'mask' must be the last field. */
93 /* Associates a metadata value (that is, a value of the OpenFlow 1.1+ metadata
94 * field) with tags for the "cls_subtable"s that contain rules that match that
96 struct cls_partition {
97 struct hmap_node hmap_node; /* In struct cls_classifier's 'partitions'
99 ovs_be64 metadata; /* metadata value for this partition. */
100 tag_type tags; /* OR of each flow's cls_subtable tag. */
101 struct tag_tracker tracker; /* Tracks the bits in 'tags'. */
104 /* Internal representation of a rule in a "struct cls_subtable". */
106 struct cls_rule *cls_rule;
107 struct hindex_node index_nodes[CLS_MAX_INDICES]; /* Within subtable's
109 struct hmap_node hmap_node; /* Within struct cls_subtable 'rules'. */
110 unsigned int priority; /* Larger numbers are higher priorities. */
111 struct cls_partition *partition;
112 struct list list; /* List of identical, lower-priority rules. */
113 struct miniflow flow; /* Matching rule. Mask is in the subtable. */
114 /* 'flow' must be the last field. */
117 static struct cls_match *
118 cls_match_alloc(struct cls_rule *rule)
120 int count = count_1bits(rule->match.flow.map);
122 struct cls_match *cls_match
123 = xmalloc(sizeof *cls_match - sizeof cls_match->flow.inline_values
124 + MINIFLOW_VALUES_SIZE(count));
126 cls_match->cls_rule = rule;
127 miniflow_clone_inline(&cls_match->flow, &rule->match.flow, count);
128 cls_match->priority = rule->priority;
129 rule->cls_match = cls_match;
134 static struct cls_subtable *find_subtable(const struct cls_classifier *,
135 const struct minimask *);
136 static struct cls_subtable *insert_subtable(struct cls_classifier *,
137 const struct minimask *);
139 static void destroy_subtable(struct cls_classifier *, struct cls_subtable *);
141 static void update_subtables_after_insertion(struct cls_classifier *,
142 struct cls_subtable *,
143 unsigned int new_priority);
144 static void update_subtables_after_removal(struct cls_classifier *,
145 struct cls_subtable *,
146 unsigned int del_priority);
148 static struct cls_match *find_match_wc(const struct cls_subtable *,
149 const struct flow *, struct trie_ctx *,
150 unsigned int n_tries,
151 struct flow_wildcards *);
152 static struct cls_match *find_equal(struct cls_subtable *,
153 const struct miniflow *, uint32_t hash);
154 static struct cls_match *insert_rule(struct cls_classifier *,
155 struct cls_subtable *, struct cls_rule *);
157 /* Iterates RULE over HEAD and all of the cls_rules on HEAD->list. */
158 #define FOR_EACH_RULE_IN_LIST(RULE, HEAD) \
159 for ((RULE) = (HEAD); (RULE) != NULL; (RULE) = next_rule_in_list(RULE))
160 #define FOR_EACH_RULE_IN_LIST_SAFE(RULE, NEXT, HEAD) \
161 for ((RULE) = (HEAD); \
162 (RULE) != NULL && ((NEXT) = next_rule_in_list(RULE), true); \
165 static struct cls_match *next_rule_in_list__(struct cls_match *);
166 static struct cls_match *next_rule_in_list(struct cls_match *);
168 static unsigned int minimask_get_prefix_len(const struct minimask *,
169 const struct mf_field *);
170 static void trie_init(struct cls_classifier *, int trie_idx,
171 const struct mf_field *);
172 static unsigned int trie_lookup(const struct cls_trie *, const struct flow *,
173 unsigned int *checkbits);
174 static unsigned int trie_lookup_value(const struct trie_node *,
175 const ovs_be32 value[],
176 unsigned int *checkbits);
177 static void trie_destroy(struct trie_node *);
178 static void trie_insert(struct cls_trie *, const struct cls_rule *, int mlen);
179 static void trie_insert_prefix(struct trie_node **, const ovs_be32 *prefix,
181 static void trie_remove(struct cls_trie *, const struct cls_rule *, int mlen);
182 static void trie_remove_prefix(struct trie_node **, const ovs_be32 *prefix,
184 static void mask_set_prefix_bits(struct flow_wildcards *, uint8_t be32ofs,
186 static bool mask_prefix_bits_set(const struct flow_wildcards *,
187 uint8_t be32ofs, unsigned int nbits);
190 cls_subtables_init(struct cls_subtables *subtables)
192 memset(subtables, 0, sizeof *subtables);
196 cls_subtables_destroy(struct cls_subtables *subtables)
198 free(subtables->array);
199 memset(subtables, 0, sizeof *subtables);
202 /* Subtables insertion. */
204 cls_subtables_push_back(struct cls_subtables *subtables,
205 struct cls_subtable_entry a)
207 if (subtables->count == subtables->alloc_size) {
208 subtables->array = x2nrealloc(subtables->array, &subtables->alloc_size,
212 subtables->array[subtables->count++] = a;
215 /* Move subtable entry at 'from' to 'to', shifting the elements in between
216 * (including the one at 'to') accordingly. */
218 cls_subtables_move(struct cls_subtable_entry *to,
219 struct cls_subtable_entry *from)
222 struct cls_subtable_entry temp = *from;
225 /* Shift entries (from,to] backwards to make space at 'to'. */
226 memmove(from, from + 1, (to - from) * sizeof *to);
228 /* Shift entries [to,from) forward to make space at 'to'. */
229 memmove(to + 1, to, (from - to) * sizeof *to);
236 /* Subtables removal. */
238 cls_subtables_remove(struct cls_subtables *subtables,
239 struct cls_subtable_entry *elem)
241 ssize_t size = (&subtables->array[subtables->count]
242 - (elem + 1)) * sizeof *elem;
244 memmove(elem, elem + 1, size);
249 #define CLS_SUBTABLES_FOR_EACH(SUBTABLE, ITER, SUBTABLES) \
250 for ((ITER) = (SUBTABLES)->array; \
251 (ITER) < &(SUBTABLES)->array[(SUBTABLES)->count] \
252 && OVS_LIKELY((SUBTABLE) = (ITER)->subtable); \
254 #define CLS_SUBTABLES_FOR_EACH_CONTINUE(SUBTABLE, ITER, SUBTABLES) \
256 (ITER) < &(SUBTABLES)->array[(SUBTABLES)->count] \
257 && OVS_LIKELY((SUBTABLE) = (ITER)->subtable); \
259 #define CLS_SUBTABLES_FOR_EACH_REVERSE(SUBTABLE, ITER, SUBTABLES) \
260 for ((ITER) = &(SUBTABLES)->array[(SUBTABLES)->count]; \
261 (ITER) > (SUBTABLES)->array \
262 && OVS_LIKELY((SUBTABLE) = (--(ITER))->subtable);)
265 cls_subtables_verify(struct cls_subtables *subtables)
267 struct cls_subtable *table;
268 struct cls_subtable_entry *iter;
269 unsigned int priority = 0;
271 CLS_SUBTABLES_FOR_EACH_REVERSE (table, iter, subtables) {
272 if (iter->max_priority != table->max_priority) {
273 VLOG_WARN("Subtable %p has mismatching priority in cache (%u != %u)",
274 table, iter->max_priority, table->max_priority);
276 if (iter->max_priority < priority) {
277 VLOG_WARN("Subtable cache is out of order (%u < %u)",
278 iter->max_priority, priority);
280 priority = iter->max_priority;
285 cls_subtables_reset(struct cls_classifier *cls)
287 struct cls_subtables old = cls->subtables;
288 struct cls_subtable *subtable;
290 VLOG_WARN("Resetting subtable cache.");
292 cls_subtables_verify(&cls->subtables);
294 cls_subtables_init(&cls->subtables);
296 HMAP_FOR_EACH (subtable, hmap_node, &cls->subtables_map) {
297 struct cls_match *head;
298 struct cls_subtable_entry elem;
299 struct cls_subtable *table;
300 struct cls_subtable_entry *iter, *from = NULL;
301 unsigned int new_max = 0;
302 unsigned int max_count = 0;
305 /* Verify max_priority. */
306 HMAP_FOR_EACH (head, hmap_node, &subtable->rules) {
307 if (head->priority > new_max) {
308 new_max = head->priority;
310 } else if (head->priority == new_max) {
314 if (new_max != subtable->max_priority ||
315 max_count != subtable->max_count) {
316 VLOG_WARN("subtable %p (%u rules) has mismatching max_priority "
317 "(%u) or max_count (%u). Highest priority found was %u, "
319 subtable, subtable->n_rules, subtable->max_priority,
320 subtable->max_count, new_max, max_count);
321 subtable->max_priority = new_max;
322 subtable->max_count = max_count;
325 /* Locate the subtable from the old cache. */
327 CLS_SUBTABLES_FOR_EACH (table, iter, &old) {
328 if (table == subtable) {
329 if (iter->max_priority != new_max) {
330 VLOG_WARN("Subtable %p has wrong max priority (%u != %u) "
332 subtable, iter->max_priority, new_max);
335 VLOG_WARN("Subtable %p duplicated in the old cache.",
342 VLOG_WARN("Subtable %p not found from the old cache.", subtable);
345 elem.subtable = subtable;
346 elem.tag = subtable->tag;
347 elem.max_priority = subtable->max_priority;
348 cls_subtables_push_back(&cls->subtables, elem);
350 /* Possibly move 'subtable' earlier in the priority array. If
351 * we break out of the loop, then the subtable (at 'from')
352 * should be moved to the position right after the current
353 * element. If the loop terminates normally, then 'iter' will
354 * be at the first array element and we'll move the subtable
355 * to the front of the array. */
356 CLS_SUBTABLES_FOR_EACH_REVERSE (table, iter, &cls->subtables) {
357 if (table == subtable) {
358 from = iter; /* Locate the subtable as we go. */
359 } else if (table->max_priority >= new_max) {
360 ovs_assert(from != NULL);
361 iter++; /* After this. */
366 /* Move subtable at 'from' to 'iter'. */
367 cls_subtables_move(iter, from);
370 /* Verify that the old and the new have the same size. */
371 if (old.count != cls->subtables.count) {
372 VLOG_WARN("subtables cache sizes differ: old (%"PRIuSIZE
373 ") != new (%"PRIuSIZE").",
374 old.count, cls->subtables.count);
377 cls_subtables_destroy(&old);
379 cls_subtables_verify(&cls->subtables);
383 /* flow/miniflow/minimask/minimatch utilities.
384 * These are only used by the classifier, so place them here to allow
385 * for better optimization. */
387 static inline uint64_t
388 miniflow_get_map_in_range(const struct miniflow *miniflow,
389 uint8_t start, uint8_t end, unsigned int *offset)
391 uint64_t map = miniflow->map;
395 uint64_t msk = (UINT64_C(1) << start) - 1; /* 'start' LSBs set */
396 *offset = count_1bits(map & msk);
399 if (end < FLOW_U32S) {
400 uint64_t msk = (UINT64_C(1) << end) - 1; /* 'end' LSBs set */
406 /* Returns a hash value for the bits of 'flow' where there are 1-bits in
407 * 'mask', given 'basis'.
409 * The hash values returned by this function are the same as those returned by
410 * miniflow_hash_in_minimask(), only the form of the arguments differ. */
411 static inline uint32_t
412 flow_hash_in_minimask(const struct flow *flow, const struct minimask *mask,
415 const uint32_t *mask_values = miniflow_get_u32_values(&mask->masks);
416 const uint32_t *flow_u32 = (const uint32_t *)flow;
417 const uint32_t *p = mask_values;
422 for (map = mask->masks.map; map; map = zero_rightmost_1bit(map)) {
423 hash = mhash_add(hash, flow_u32[raw_ctz(map)] & *p++);
426 return mhash_finish(hash, (p - mask_values) * 4);
429 /* Returns a hash value for the bits of 'flow' where there are 1-bits in
430 * 'mask', given 'basis'.
432 * The hash values returned by this function are the same as those returned by
433 * flow_hash_in_minimask(), only the form of the arguments differ. */
434 static inline uint32_t
435 miniflow_hash_in_minimask(const struct miniflow *flow,
436 const struct minimask *mask, uint32_t basis)
438 const uint32_t *mask_values = miniflow_get_u32_values(&mask->masks);
439 const uint32_t *p = mask_values;
440 uint32_t hash = basis;
443 MINIFLOW_FOR_EACH_IN_MAP(flow_u32, flow, mask->masks.map) {
444 hash = mhash_add(hash, flow_u32 & *p++);
447 return mhash_finish(hash, (p - mask_values) * 4);
450 /* Returns a hash value for the bits of range [start, end) in 'flow',
451 * where there are 1-bits in 'mask', given 'hash'.
453 * The hash values returned by this function are the same as those returned by
454 * minimatch_hash_range(), only the form of the arguments differ. */
455 static inline uint32_t
456 flow_hash_in_minimask_range(const struct flow *flow,
457 const struct minimask *mask,
458 uint8_t start, uint8_t end, uint32_t *basis)
460 const uint32_t *mask_values = miniflow_get_u32_values(&mask->masks);
461 const uint32_t *flow_u32 = (const uint32_t *)flow;
463 uint64_t map = miniflow_get_map_in_range(&mask->masks, start, end,
465 const uint32_t *p = mask_values + offset;
466 uint32_t hash = *basis;
468 for (; map; map = zero_rightmost_1bit(map)) {
469 hash = mhash_add(hash, flow_u32[raw_ctz(map)] & *p++);
472 *basis = hash; /* Allow continuation from the unfinished value. */
473 return mhash_finish(hash, (p - mask_values) * 4);
476 /* Fold minimask 'mask''s wildcard mask into 'wc's wildcard mask. */
478 flow_wildcards_fold_minimask(struct flow_wildcards *wc,
479 const struct minimask *mask)
481 flow_union_with_miniflow(&wc->masks, &mask->masks);
484 /* Fold minimask 'mask''s wildcard mask into 'wc's wildcard mask
485 * in range [start, end). */
487 flow_wildcards_fold_minimask_range(struct flow_wildcards *wc,
488 const struct minimask *mask,
489 uint8_t start, uint8_t end)
491 uint32_t *dst_u32 = (uint32_t *)&wc->masks;
493 uint64_t map = miniflow_get_map_in_range(&mask->masks, start, end,
495 const uint32_t *p = miniflow_get_u32_values(&mask->masks) + offset;
497 for (; map; map = zero_rightmost_1bit(map)) {
498 dst_u32[raw_ctz(map)] |= *p++;
502 /* Returns a hash value for 'flow', given 'basis'. */
503 static inline uint32_t
504 miniflow_hash(const struct miniflow *flow, uint32_t basis)
506 const uint32_t *values = miniflow_get_u32_values(flow);
507 const uint32_t *p = values;
508 uint32_t hash = basis;
509 uint64_t hash_map = 0;
512 for (map = flow->map; map; map = zero_rightmost_1bit(map)) {
514 hash = mhash_add(hash, *p);
515 hash_map |= rightmost_1bit(map);
519 hash = mhash_add(hash, hash_map);
520 hash = mhash_add(hash, hash_map >> 32);
522 return mhash_finish(hash, p - values);
525 /* Returns a hash value for 'mask', given 'basis'. */
526 static inline uint32_t
527 minimask_hash(const struct minimask *mask, uint32_t basis)
529 return miniflow_hash(&mask->masks, basis);
532 /* Returns a hash value for 'match', given 'basis'. */
533 static inline uint32_t
534 minimatch_hash(const struct minimatch *match, uint32_t basis)
536 return miniflow_hash(&match->flow, minimask_hash(&match->mask, basis));
539 /* Returns a hash value for the bits of range [start, end) in 'minimatch',
542 * The hash values returned by this function are the same as those returned by
543 * flow_hash_in_minimask_range(), only the form of the arguments differ. */
544 static inline uint32_t
545 minimatch_hash_range(const struct minimatch *match, uint8_t start, uint8_t end,
549 const uint32_t *p, *q;
550 uint32_t hash = *basis;
553 n = count_1bits(miniflow_get_map_in_range(&match->mask.masks, start, end,
555 q = miniflow_get_u32_values(&match->mask.masks) + offset;
556 p = miniflow_get_u32_values(&match->flow) + offset;
558 for (i = 0; i < n; i++) {
559 hash = mhash_add(hash, p[i] & q[i]);
561 *basis = hash; /* Allow continuation from the unfinished value. */
562 return mhash_finish(hash, (offset + n) * 4);
568 /* Initializes 'rule' to match packets specified by 'match' at the given
569 * 'priority'. 'match' must satisfy the invariant described in the comment at
570 * the definition of struct match.
572 * The caller must eventually destroy 'rule' with cls_rule_destroy().
574 * (OpenFlow uses priorities between 0 and UINT16_MAX, inclusive, but
575 * internally Open vSwitch supports a wider range.) */
577 cls_rule_init(struct cls_rule *rule,
578 const struct match *match, unsigned int priority)
580 minimatch_init(&rule->match, match);
581 rule->priority = priority;
582 rule->cls_match = NULL;
585 /* Same as cls_rule_init() for initialization from a "struct minimatch". */
587 cls_rule_init_from_minimatch(struct cls_rule *rule,
588 const struct minimatch *match,
589 unsigned int priority)
591 minimatch_clone(&rule->match, match);
592 rule->priority = priority;
593 rule->cls_match = NULL;
596 /* Initializes 'dst' as a copy of 'src'.
598 * The caller must eventually destroy 'dst' with cls_rule_destroy(). */
600 cls_rule_clone(struct cls_rule *dst, const struct cls_rule *src)
602 minimatch_clone(&dst->match, &src->match);
603 dst->priority = src->priority;
604 dst->cls_match = NULL;
607 /* Initializes 'dst' with the data in 'src', destroying 'src'.
609 * The caller must eventually destroy 'dst' with cls_rule_destroy(). */
611 cls_rule_move(struct cls_rule *dst, struct cls_rule *src)
613 minimatch_move(&dst->match, &src->match);
614 dst->priority = src->priority;
615 dst->cls_match = NULL;
618 /* Frees memory referenced by 'rule'. Doesn't free 'rule' itself (it's
619 * normally embedded into a larger structure).
621 * ('rule' must not currently be in a classifier.) */
623 cls_rule_destroy(struct cls_rule *rule)
625 ovs_assert(!rule->cls_match);
626 minimatch_destroy(&rule->match);
629 /* Returns true if 'a' and 'b' match the same packets at the same priority,
630 * false if they differ in some way. */
632 cls_rule_equal(const struct cls_rule *a, const struct cls_rule *b)
634 return a->priority == b->priority && minimatch_equal(&a->match, &b->match);
637 /* Returns a hash value for 'rule', folding in 'basis'. */
639 cls_rule_hash(const struct cls_rule *rule, uint32_t basis)
641 return minimatch_hash(&rule->match, hash_int(rule->priority, basis));
644 /* Appends a string describing 'rule' to 's'. */
646 cls_rule_format(const struct cls_rule *rule, struct ds *s)
648 minimatch_format(&rule->match, s, rule->priority);
651 /* Returns true if 'rule' matches every packet, false otherwise. */
653 cls_rule_is_catchall(const struct cls_rule *rule)
655 return minimask_is_catchall(&rule->match.mask);
658 /* Initializes 'cls' as a classifier that initially contains no classification
661 classifier_init(struct classifier *cls_, const uint8_t *flow_segments)
663 struct cls_classifier *cls = xmalloc(sizeof *cls);
665 fat_rwlock_init(&cls_->rwlock);
670 hmap_init(&cls->subtables_map);
671 cls_subtables_init(&cls->subtables);
672 hmap_init(&cls->partitions);
673 cls->n_flow_segments = 0;
675 while (cls->n_flow_segments < CLS_MAX_INDICES
676 && *flow_segments < FLOW_U32S) {
677 cls->flow_segments[cls->n_flow_segments++] = *flow_segments++;
683 /* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
684 * caller's responsibility. */
686 classifier_destroy(struct classifier *cls_)
689 struct cls_classifier *cls = cls_->cls;
690 struct cls_subtable *partition, *next_partition;
691 struct cls_subtable *subtable, *next_subtable;
694 fat_rwlock_destroy(&cls_->rwlock);
699 for (i = 0; i < cls->n_tries; i++) {
700 trie_destroy(cls->tries[i].root);
703 HMAP_FOR_EACH_SAFE (subtable, next_subtable, hmap_node,
704 &cls->subtables_map) {
705 destroy_subtable(cls, subtable);
707 hmap_destroy(&cls->subtables_map);
709 HMAP_FOR_EACH_SAFE (partition, next_partition, hmap_node,
711 hmap_remove(&cls->partitions, &partition->hmap_node);
714 hmap_destroy(&cls->partitions);
716 cls_subtables_destroy(&cls->subtables);
721 /* We use uint64_t as a set for the fields below. */
722 BUILD_ASSERT_DECL(MFF_N_IDS <= 64);
724 /* Set the fields for which prefix lookup should be performed. */
726 classifier_set_prefix_fields(struct classifier *cls_,
727 const enum mf_field_id *trie_fields,
728 unsigned int n_fields)
730 struct cls_classifier *cls = cls_->cls;
734 for (i = 0, trie = 0; i < n_fields && trie < CLS_MAX_TRIES; i++) {
735 const struct mf_field *field = mf_from_id(trie_fields[i]);
736 if (field->flow_be32ofs < 0 || field->n_bits % 32) {
737 /* Incompatible field. This is the only place where we
738 * enforce these requirements, but the rest of the trie code
739 * depends on the flow_be32ofs to be non-negative and the
740 * field length to be a multiple of 32 bits. */
744 if (fields & (UINT64_C(1) << trie_fields[i])) {
745 /* Duplicate field, there is no need to build more than
746 * one index for any one field. */
749 fields |= UINT64_C(1) << trie_fields[i];
751 if (trie >= cls->n_tries || field != cls->tries[trie].field) {
752 trie_init(cls, trie, field);
757 /* Destroy the rest. */
758 for (i = trie; i < cls->n_tries; i++) {
759 trie_init(cls, i, NULL);
765 trie_init(struct cls_classifier *cls, int trie_idx,
766 const struct mf_field *field)
768 struct cls_trie *trie = &cls->tries[trie_idx];
769 struct cls_subtable *subtable;
770 struct cls_subtable_entry *iter;
772 if (trie_idx < cls->n_tries) {
773 trie_destroy(trie->root);
778 /* Add existing rules to the trie. */
779 CLS_SUBTABLES_FOR_EACH (subtable, iter, &cls->subtables) {
782 plen = field ? minimask_get_prefix_len(&subtable->mask, field) : 0;
783 /* Initialize subtable's prefix length on this field. */
784 subtable->trie_plen[trie_idx] = plen;
787 struct cls_match *head;
789 HMAP_FOR_EACH (head, hmap_node, &subtable->rules) {
790 struct cls_match *match;
792 FOR_EACH_RULE_IN_LIST (match, head) {
793 trie_insert(trie, match->cls_rule, plen);
800 /* Returns true if 'cls' contains no classification rules, false otherwise. */
802 classifier_is_empty(const struct classifier *cls)
804 return cls->cls->n_rules == 0;
807 /* Returns the number of rules in 'cls'. */
809 classifier_count(const struct classifier *cls)
811 return cls->cls->n_rules;
815 hash_metadata(ovs_be64 metadata_)
817 uint64_t metadata = (OVS_FORCE uint64_t) metadata_;
818 return hash_uint64(metadata);
821 static struct cls_partition *
822 find_partition(const struct cls_classifier *cls, ovs_be64 metadata,
825 struct cls_partition *partition;
827 HMAP_FOR_EACH_IN_BUCKET (partition, hmap_node, hash, &cls->partitions) {
828 if (partition->metadata == metadata) {
836 static struct cls_partition *
837 create_partition(struct cls_classifier *cls, struct cls_subtable *subtable,
840 uint32_t hash = hash_metadata(metadata);
841 struct cls_partition *partition = find_partition(cls, metadata, hash);
843 partition = xmalloc(sizeof *partition);
844 partition->metadata = metadata;
846 tag_tracker_init(&partition->tracker);
847 hmap_insert(&cls->partitions, &partition->hmap_node, hash);
849 tag_tracker_add(&partition->tracker, &partition->tags, subtable->tag);
853 static inline ovs_be32 minimatch_get_ports(const struct minimatch *match)
855 /* Could optimize to use the same map if needed for fast path. */
856 return MINIFLOW_GET_BE32(&match->flow, tp_src)
857 & MINIFLOW_GET_BE32(&match->mask.masks, tp_src);
860 /* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller
861 * must not modify or free it.
863 * If 'cls' already contains an identical rule (including wildcards, values of
864 * fixed fields, and priority), replaces the old rule by 'rule' and returns the
865 * rule that was replaced. The caller takes ownership of the returned rule and
866 * is thus responsible for destroying it with cls_rule_destroy(), freeing the
867 * memory block in which it resides, etc., as necessary.
869 * Returns NULL if 'cls' does not contain a rule with an identical key, after
870 * inserting the new rule. In this case, no rules are displaced by the new
871 * rule, even rules that cannot have any effect because the new rule matches a
872 * superset of their flows and has higher priority. */
874 classifier_replace(struct classifier *cls_, struct cls_rule *rule)
876 struct cls_classifier *cls = cls_->cls;
877 struct cls_match *old_rule;
878 struct cls_subtable *subtable;
880 subtable = find_subtable(cls, &rule->match.mask);
882 subtable = insert_subtable(cls, &rule->match.mask);
885 old_rule = insert_rule(cls, subtable, rule);
889 rule->cls_match->partition = NULL;
890 if (minimask_get_metadata_mask(&rule->match.mask) == OVS_BE64_MAX) {
891 ovs_be64 metadata = miniflow_get_metadata(&rule->match.flow);
892 rule->cls_match->partition = create_partition(cls, subtable,
899 for (i = 0; i < cls->n_tries; i++) {
900 if (subtable->trie_plen[i]) {
901 trie_insert(&cls->tries[i], rule, subtable->trie_plen[i]);
906 if (subtable->ports_mask_len) {
907 /* We mask the value to be inserted to always have the wildcarded
908 * bits in known (zero) state, so we can include them in comparison
909 * and they will always match (== their original value does not
911 ovs_be32 masked_ports = minimatch_get_ports(&rule->match);
913 trie_insert_prefix(&subtable->ports_trie, &masked_ports,
914 subtable->ports_mask_len);
919 struct cls_rule *old_cls_rule = old_rule->cls_rule;
921 rule->cls_match->partition = old_rule->partition;
922 old_cls_rule->cls_match = NULL;
928 /* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller
929 * must not modify or free it.
931 * 'cls' must not contain an identical rule (including wildcards, values of
932 * fixed fields, and priority). Use classifier_find_rule_exactly() to find
935 classifier_insert(struct classifier *cls, struct cls_rule *rule)
937 struct cls_rule *displaced_rule = classifier_replace(cls, rule);
938 ovs_assert(!displaced_rule);
941 /* Removes 'rule' from 'cls'. It is the caller's responsibility to destroy
942 * 'rule' with cls_rule_destroy(), freeing the memory block in which 'rule'
943 * resides, etc., as necessary. */
945 classifier_remove(struct classifier *cls_, struct cls_rule *rule)
947 struct cls_classifier *cls = cls_->cls;
948 struct cls_partition *partition;
949 struct cls_match *cls_match = rule->cls_match;
950 struct cls_match *head;
951 struct cls_subtable *subtable;
954 ovs_assert(cls_match);
956 subtable = find_subtable(cls, &rule->match.mask);
957 ovs_assert(subtable);
959 if (subtable->ports_mask_len) {
960 ovs_be32 masked_ports = minimatch_get_ports(&rule->match);
962 trie_remove_prefix(&subtable->ports_trie,
963 &masked_ports, subtable->ports_mask_len);
965 for (i = 0; i < cls->n_tries; i++) {
966 if (subtable->trie_plen[i]) {
967 trie_remove(&cls->tries[i], rule, subtable->trie_plen[i]);
971 /* Remove rule node from indices. */
972 for (i = 0; i < subtable->n_indices; i++) {
973 hindex_remove(&subtable->indices[i], &cls_match->index_nodes[i]);
976 head = find_equal(subtable, &rule->match.flow, cls_match->hmap_node.hash);
977 if (head != cls_match) {
978 list_remove(&cls_match->list);
979 } else if (list_is_empty(&cls_match->list)) {
980 hmap_remove(&subtable->rules, &cls_match->hmap_node);
982 struct cls_match *next = CONTAINER_OF(cls_match->list.next,
983 struct cls_match, list);
985 list_remove(&cls_match->list);
986 hmap_replace(&subtable->rules, &cls_match->hmap_node,
990 partition = cls_match->partition;
992 tag_tracker_subtract(&partition->tracker, &partition->tags,
994 if (!partition->tags) {
995 hmap_remove(&cls->partitions, &partition->hmap_node);
1000 if (--subtable->n_rules == 0) {
1001 destroy_subtable(cls, subtable);
1003 update_subtables_after_removal(cls, subtable, cls_match->priority);
1008 rule->cls_match = NULL;
1012 /* Prefix tree context. Valid when 'lookup_done' is true. Can skip all
1013 * subtables which have more than 'match_plen' bits in their corresponding
1014 * field at offset 'be32ofs'. If skipped, 'maskbits' prefix bits should be
1015 * unwildcarded to quarantee datapath flow matches only packets it should. */
1017 const struct cls_trie *trie;
1018 bool lookup_done; /* Status of the lookup. */
1019 uint8_t be32ofs; /* U32 offset of the field in question. */
1020 unsigned int match_plen; /* Longest prefix than could possibly match. */
1021 unsigned int maskbits; /* Prefix length needed to avoid false matches. */
1025 trie_ctx_init(struct trie_ctx *ctx, const struct cls_trie *trie)
1028 ctx->be32ofs = trie->field->flow_be32ofs;
1029 ctx->lookup_done = false;
1033 lookahead_subtable(const struct cls_subtable_entry *subtables)
1035 ovs_prefetch_range(subtables->subtable, sizeof *subtables->subtable);
1038 /* Finds and returns the highest-priority rule in 'cls' that matches 'flow'.
1039 * Returns a null pointer if no rules in 'cls' match 'flow'. If multiple rules
1040 * of equal priority match 'flow', returns one arbitrarily.
1042 * If a rule is found and 'wc' is non-null, bitwise-OR's 'wc' with the
1043 * set of bits that were significant in the lookup. At some point
1044 * earlier, 'wc' should have been initialized (e.g., by
1045 * flow_wildcards_init_catchall()). */
1047 classifier_lookup(const struct classifier *cls_, const struct flow *flow,
1048 struct flow_wildcards *wc)
1050 struct cls_classifier *cls = cls_->cls;
1051 const struct cls_partition *partition;
1053 struct cls_match *best;
1054 struct trie_ctx trie_ctx[CLS_MAX_TRIES];
1056 struct cls_subtable_entry *subtables = cls->subtables.array;
1057 int n_subtables = cls->subtables.count;
1058 int64_t best_priority = -1;
1060 /* Prefetch the subtables array. */
1061 ovs_prefetch_range(subtables, n_subtables * sizeof *subtables);
1063 /* Determine 'tags' such that, if 'subtable->tag' doesn't intersect them,
1064 * then 'flow' cannot possibly match in 'subtable':
1066 * - If flow->metadata maps to a given 'partition', then we can use
1067 * 'tags' for 'partition->tags'.
1069 * - If flow->metadata has no partition, then no rule in 'cls' has an
1070 * exact-match for flow->metadata. That means that we don't need to
1071 * search any subtable that includes flow->metadata in its mask.
1073 * In either case, we always need to search any cls_subtables that do not
1074 * include flow->metadata in its mask. One way to do that would be to
1075 * check the "cls_subtable"s explicitly for that, but that would require an
1076 * extra branch per subtable. Instead, we mark such a cls_subtable's
1077 * 'tags' as TAG_ALL and make sure that 'tags' is never empty. This means
1078 * that 'tags' always intersects such a cls_subtable's 'tags', so we don't
1079 * need a special case.
1081 partition = (hmap_is_empty(&cls->partitions)
1083 : find_partition(cls, flow->metadata,
1084 hash_metadata(flow->metadata)));
1085 tags = partition ? partition->tags : TAG_ARBITRARY;
1087 /* Initialize trie contexts for match_find_wc(). */
1088 for (i = 0; i < cls->n_tries; i++) {
1089 trie_ctx_init(&trie_ctx[i], &cls->tries[i]);
1092 /* Prefetch the first subtables. */
1093 if (n_subtables > 1) {
1094 lookahead_subtable(subtables);
1095 lookahead_subtable(subtables + 1);
1099 for (i = 0; OVS_LIKELY(i < n_subtables); i++) {
1100 struct cls_match *rule;
1102 if ((int64_t)subtables[i].max_priority <= best_priority) {
1103 /* Subtables are in descending priority order,
1104 * can not find anything better. */
1108 /* Prefetch a forthcoming subtable. */
1109 if (i + 2 < n_subtables) {
1110 lookahead_subtable(&subtables[i + 2]);
1113 if (!tag_intersects(tags, subtables[i].tag)) {
1117 rule = find_match_wc(subtables[i].subtable, flow, trie_ctx,
1119 if (rule && (int64_t)rule->priority > best_priority) {
1120 best_priority = (int64_t)rule->priority;
1125 return best ? best->cls_rule : NULL;
1128 /* Returns true if 'target' satisifies 'match', that is, if each bit for which
1129 * 'match' specifies a particular value has the correct value in 'target'.
1131 * 'flow' and 'mask' have the same mask! */
1133 miniflow_and_mask_matches_miniflow(const struct miniflow *flow,
1134 const struct minimask *mask,
1135 const struct miniflow *target)
1137 const uint32_t *flowp = miniflow_get_u32_values(flow);
1138 const uint32_t *maskp = miniflow_get_u32_values(&mask->masks);
1139 uint32_t target_u32;
1141 MINIFLOW_FOR_EACH_IN_MAP(target_u32, target, mask->masks.map) {
1142 if ((*flowp++ ^ target_u32) & *maskp++) {
1150 static inline struct cls_match *
1151 find_match_miniflow(const struct cls_subtable *subtable,
1152 const struct miniflow *flow,
1155 struct cls_match *rule;
1157 HMAP_FOR_EACH_WITH_HASH (rule, hmap_node, hash, &subtable->rules) {
1158 if (miniflow_and_mask_matches_miniflow(&rule->flow, &subtable->mask,
1167 /* Finds and returns the highest-priority rule in 'cls' that matches
1168 * 'miniflow'. Returns a null pointer if no rules in 'cls' match 'flow'.
1169 * If multiple rules of equal priority match 'flow', returns one arbitrarily.
1171 * This function is optimized for the userspace datapath, which only ever has
1172 * one priority value for it's flows!
1174 struct cls_rule *classifier_lookup_miniflow_first(const struct classifier *cls_,
1175 const struct miniflow *flow)
1177 struct cls_classifier *cls = cls_->cls;
1178 struct cls_subtable *subtable;
1179 struct cls_subtable_entry *iter;
1181 CLS_SUBTABLES_FOR_EACH (subtable, iter, &cls->subtables) {
1182 struct cls_match *rule;
1184 rule = find_match_miniflow(subtable, flow,
1185 miniflow_hash_in_minimask(flow,
1189 return rule->cls_rule;
1196 /* Finds and returns a rule in 'cls' with exactly the same priority and
1197 * matching criteria as 'target'. Returns a null pointer if 'cls' doesn't
1198 * contain an exact match. */
1200 classifier_find_rule_exactly(const struct classifier *cls_,
1201 const struct cls_rule *target)
1203 struct cls_classifier *cls = cls_->cls;
1204 struct cls_match *head, *rule;
1205 struct cls_subtable *subtable;
1207 subtable = find_subtable(cls, &target->match.mask);
1212 /* Skip if there is no hope. */
1213 if (target->priority > subtable->max_priority) {
1217 head = find_equal(subtable, &target->match.flow,
1218 miniflow_hash_in_minimask(&target->match.flow,
1219 &target->match.mask, 0));
1220 FOR_EACH_RULE_IN_LIST (rule, head) {
1221 if (target->priority >= rule->priority) {
1222 return target->priority == rule->priority ? rule->cls_rule : NULL;
1228 /* Finds and returns a rule in 'cls' with priority 'priority' and exactly the
1229 * same matching criteria as 'target'. Returns a null pointer if 'cls' doesn't
1230 * contain an exact match. */
1232 classifier_find_match_exactly(const struct classifier *cls,
1233 const struct match *target,
1234 unsigned int priority)
1236 struct cls_rule *retval;
1239 cls_rule_init(&cr, target, priority);
1240 retval = classifier_find_rule_exactly(cls, &cr);
1241 cls_rule_destroy(&cr);
1246 /* Checks if 'target' would overlap any other rule in 'cls'. Two rules are
1247 * considered to overlap if both rules have the same priority and a packet
1248 * could match both. */
1250 classifier_rule_overlaps(const struct classifier *cls_,
1251 const struct cls_rule *target)
1253 struct cls_classifier *cls = cls_->cls;
1254 struct cls_subtable *subtable;
1255 struct cls_subtable_entry *iter;
1257 /* Iterate subtables in the descending max priority order. */
1258 CLS_SUBTABLES_FOR_EACH (subtable, iter, &cls->subtables) {
1259 uint32_t storage[FLOW_U32S];
1260 struct minimask mask;
1261 struct cls_match *head;
1263 if (target->priority > iter->max_priority) {
1264 break; /* Can skip this and the rest of the subtables. */
1267 minimask_combine(&mask, &target->match.mask, &subtable->mask, storage);
1268 HMAP_FOR_EACH (head, hmap_node, &subtable->rules) {
1269 struct cls_match *rule;
1271 FOR_EACH_RULE_IN_LIST (rule, head) {
1272 if (rule->priority < target->priority) {
1273 break; /* Rules in descending priority order. */
1275 if (rule->priority == target->priority
1276 && miniflow_equal_in_minimask(&target->match.flow,
1277 &rule->flow, &mask)) {
1287 /* Returns true if 'rule' exactly matches 'criteria' or if 'rule' is more
1288 * specific than 'criteria'. That is, 'rule' matches 'criteria' and this
1289 * function returns true if, for every field:
1291 * - 'criteria' and 'rule' specify the same (non-wildcarded) value for the
1294 * - 'criteria' wildcards the field,
1296 * Conversely, 'rule' does not match 'criteria' and this function returns false
1297 * if, for at least one field:
1299 * - 'criteria' and 'rule' specify different values for the field, or
1301 * - 'criteria' specifies a value for the field but 'rule' wildcards it.
1303 * Equivalently, the truth table for whether a field matches is:
1308 * r +---------+---------+
1309 * i wild | yes | yes |
1311 * e +---------+---------+
1312 * r exact | no |if values|
1314 * a +---------+---------+
1316 * This is the matching rule used by OpenFlow 1.0 non-strict OFPT_FLOW_MOD
1317 * commands and by OpenFlow 1.0 aggregate and flow stats.
1319 * Ignores rule->priority. */
1321 cls_rule_is_loose_match(const struct cls_rule *rule,
1322 const struct minimatch *criteria)
1324 return (!minimask_has_extra(&rule->match.mask, &criteria->mask)
1325 && miniflow_equal_in_minimask(&rule->match.flow, &criteria->flow,
1332 rule_matches(const struct cls_match *rule, const struct cls_rule *target)
1335 || miniflow_equal_in_minimask(&rule->flow,
1336 &target->match.flow,
1337 &target->match.mask));
1340 static struct cls_match *
1341 search_subtable(const struct cls_subtable *subtable,
1342 const struct cls_rule *target)
1344 if (!target || !minimask_has_extra(&subtable->mask, &target->match.mask)) {
1345 struct cls_match *rule;
1347 HMAP_FOR_EACH (rule, hmap_node, &subtable->rules) {
1348 if (rule_matches(rule, target)) {
1356 /* Initializes 'cursor' for iterating through rules in 'cls':
1358 * - If 'target' is null, the cursor will visit every rule in 'cls'.
1360 * - If 'target' is nonnull, the cursor will visit each 'rule' in 'cls'
1361 * such that cls_rule_is_loose_match(rule, target) returns true.
1363 * Ignores target->priority. */
1365 cls_cursor_init(struct cls_cursor *cursor, const struct classifier *cls,
1366 const struct cls_rule *target)
1368 cursor->cls = cls->cls;
1369 cursor->target = target && !cls_rule_is_catchall(target) ? target : NULL;
1372 /* Returns the first matching cls_rule in 'cursor''s iteration, or a null
1373 * pointer if there are no matches. */
1375 cls_cursor_first(struct cls_cursor *cursor)
1377 struct cls_subtable *subtable;
1379 HMAP_FOR_EACH (subtable, hmap_node, &cursor->cls->subtables_map) {
1380 struct cls_match *rule = search_subtable(subtable, cursor->target);
1382 cursor->subtable = subtable;
1383 return rule->cls_rule;
1390 /* Returns the next matching cls_rule in 'cursor''s iteration, or a null
1391 * pointer if there are no more matches. */
1393 cls_cursor_next(struct cls_cursor *cursor, const struct cls_rule *rule_)
1395 struct cls_match *rule = CONST_CAST(struct cls_match *, rule_->cls_match);
1396 const struct cls_subtable *subtable;
1397 struct cls_match *next;
1399 next = next_rule_in_list__(rule);
1400 if (next->priority < rule->priority) {
1401 return next->cls_rule;
1404 /* 'next' is the head of the list, that is, the rule that is included in
1405 * the subtable's hmap. (This is important when the classifier contains
1406 * rules that differ only in priority.) */
1408 HMAP_FOR_EACH_CONTINUE (rule, hmap_node, &cursor->subtable->rules) {
1409 if (rule_matches(rule, cursor->target)) {
1410 return rule->cls_rule;
1414 subtable = cursor->subtable;
1415 HMAP_FOR_EACH_CONTINUE (subtable, hmap_node, &cursor->cls->subtables_map) {
1416 rule = search_subtable(subtable, cursor->target);
1418 cursor->subtable = subtable;
1419 return rule->cls_rule;
1426 static struct cls_subtable *
1427 find_subtable(const struct cls_classifier *cls, const struct minimask *mask)
1429 struct cls_subtable *subtable;
1431 HMAP_FOR_EACH_IN_BUCKET (subtable, hmap_node, minimask_hash(mask, 0),
1432 &cls->subtables_map) {
1433 if (minimask_equal(mask, &subtable->mask)) {
1440 static struct cls_subtable *
1441 insert_subtable(struct cls_classifier *cls, const struct minimask *mask)
1443 uint32_t hash = minimask_hash(mask, 0);
1444 struct cls_subtable *subtable;
1446 struct flow_wildcards old, new;
1448 struct cls_subtable_entry elem;
1449 int count = count_1bits(mask->masks.map);
1451 subtable = xzalloc(sizeof *subtable - sizeof mask->masks.inline_values
1452 + MINIFLOW_VALUES_SIZE(count));
1453 hmap_init(&subtable->rules);
1454 miniflow_clone_inline(&subtable->mask.masks, &mask->masks, count);
1456 /* Init indices for segmented lookup, if any. */
1457 flow_wildcards_init_catchall(&new);
1460 for (i = 0; i < cls->n_flow_segments; i++) {
1461 flow_wildcards_fold_minimask_range(&new, mask, prev,
1462 cls->flow_segments[i]);
1463 /* Add an index if it adds mask bits. */
1464 if (!flow_wildcards_equal(&new, &old)) {
1465 hindex_init(&subtable->indices[index]);
1466 subtable->index_ofs[index] = cls->flow_segments[i];
1470 prev = cls->flow_segments[i];
1472 /* Check if the rest of the subtable's mask adds any bits,
1473 * and remove the last index if it doesn't. */
1475 flow_wildcards_fold_minimask_range(&new, mask, prev, FLOW_U32S);
1476 if (flow_wildcards_equal(&new, &old)) {
1478 subtable->index_ofs[index] = 0;
1479 hindex_destroy(&subtable->indices[index]);
1482 subtable->n_indices = index;
1484 subtable->tag = (minimask_get_metadata_mask(mask) == OVS_BE64_MAX
1485 ? tag_create_deterministic(hash)
1488 for (i = 0; i < cls->n_tries; i++) {
1489 subtable->trie_plen[i] = minimask_get_prefix_len(mask,
1490 cls->tries[i].field);
1494 subtable->ports_trie = NULL;
1495 subtable->ports_mask_len
1496 = 32 - ctz32(ntohl(MINIFLOW_GET_BE32(&mask->masks, tp_src)));
1498 hmap_insert(&cls->subtables_map, &subtable->hmap_node, hash);
1499 elem.subtable = subtable;
1500 elem.tag = subtable->tag;
1501 elem.max_priority = subtable->max_priority;
1502 cls_subtables_push_back(&cls->subtables, elem);
1508 destroy_subtable(struct cls_classifier *cls, struct cls_subtable *subtable)
1511 struct cls_subtable *table = NULL;
1512 struct cls_subtable_entry *iter;
1514 CLS_SUBTABLES_FOR_EACH (table, iter, &cls->subtables) {
1515 if (table == subtable) {
1516 cls_subtables_remove(&cls->subtables, iter);
1521 trie_destroy(subtable->ports_trie);
1523 for (i = 0; i < subtable->n_indices; i++) {
1524 hindex_destroy(&subtable->indices[i]);
1526 minimask_destroy(&subtable->mask);
1527 hmap_remove(&cls->subtables_map, &subtable->hmap_node);
1528 hmap_destroy(&subtable->rules);
1532 /* This function performs the following updates for 'subtable' in 'cls'
1533 * following the addition of a new rule with priority 'new_priority' to
1536 * - Update 'subtable->max_priority' and 'subtable->max_count' if necessary.
1538 * - Update 'subtable''s position in 'cls->subtables' if necessary.
1540 * This function should only be called after adding a new rule, not after
1541 * replacing a rule by an identical one or modifying a rule in-place. */
1543 update_subtables_after_insertion(struct cls_classifier *cls,
1544 struct cls_subtable *subtable,
1545 unsigned int new_priority)
1547 if (new_priority == subtable->max_priority) {
1548 ++subtable->max_count;
1549 } else if (new_priority > subtable->max_priority) {
1550 struct cls_subtable *table;
1551 struct cls_subtable_entry *iter, *from = NULL;
1553 subtable->max_priority = new_priority;
1554 subtable->max_count = 1;
1556 /* Possibly move 'subtable' earlier in the priority array. If
1557 * we break out of the loop, then the subtable (at 'from')
1558 * should be moved to the position right after the current
1559 * element. If the loop terminates normally, then 'iter' will
1560 * be at the first array element and we'll move the subtable
1561 * to the front of the array. */
1562 CLS_SUBTABLES_FOR_EACH_REVERSE (table, iter, &cls->subtables) {
1563 if (table == subtable) {
1564 from = iter; /* Locate the subtable as we go. */
1565 iter->max_priority = new_priority;
1566 } else if (table->max_priority >= new_priority) {
1568 /* Corrupted cache? */
1569 cls_subtables_reset(cls);
1570 VLOG_ABORT("update_subtables_after_insertion(): Subtable priority list corrupted.");
1573 iter++; /* After this. */
1578 /* Move subtable at 'from' to 'iter'. */
1579 cls_subtables_move(iter, from);
1583 /* This function performs the following updates for 'subtable' in 'cls'
1584 * following the deletion of a rule with priority 'del_priority' from
1587 * - Update 'subtable->max_priority' and 'subtable->max_count' if necessary.
1589 * - Update 'subtable''s position in 'cls->subtables' if necessary.
1591 * This function should only be called after removing a rule, not after
1592 * replacing a rule by an identical one or modifying a rule in-place. */
1594 update_subtables_after_removal(struct cls_classifier *cls,
1595 struct cls_subtable *subtable,
1596 unsigned int del_priority)
1598 if (del_priority == subtable->max_priority && --subtable->max_count == 0) {
1599 struct cls_match *head;
1600 struct cls_subtable *table;
1601 struct cls_subtable_entry *iter, *from = NULL;
1603 subtable->max_priority = 0;
1604 HMAP_FOR_EACH (head, hmap_node, &subtable->rules) {
1605 if (head->priority > subtable->max_priority) {
1606 subtable->max_priority = head->priority;
1607 subtable->max_count = 1;
1608 } else if (head->priority == subtable->max_priority) {
1609 ++subtable->max_count;
1613 /* Possibly move 'subtable' later in the priority array.
1614 * After the loop the 'iter' will point right after the position
1615 * at which the subtable should be moved (either at a subtable
1616 * with an equal or lower priority, or just past the array),
1617 * so it is decremented once. */
1618 CLS_SUBTABLES_FOR_EACH (table, iter, &cls->subtables) {
1619 if (table == subtable) {
1620 from = iter; /* Locate the subtable as we go. */
1621 iter->max_priority = subtable->max_priority;
1622 } else if (table->max_priority <= subtable->max_priority) {
1624 /* Corrupted cache? */
1625 cls_subtables_reset(cls);
1626 VLOG_ABORT("update_subtables_after_removal(): Subtable priority list corrupted.");
1632 /* Now at one past the destination. */
1635 /* Move subtable at 'from' to 'iter'. */
1636 cls_subtables_move(iter, from);
1645 /* Return 'true' if can skip rest of the subtable based on the prefix trie
1646 * lookup results. */
1648 check_tries(struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries,
1649 const unsigned int field_plen[CLS_MAX_TRIES],
1650 const struct range ofs, const struct flow *flow,
1651 struct flow_wildcards *wc)
1655 /* Check if we could avoid fully unwildcarding the next level of
1656 * fields using the prefix tries. The trie checks are done only as
1657 * needed to avoid folding in additional bits to the wildcards mask. */
1658 for (j = 0; j < n_tries; j++) {
1659 /* Is the trie field relevant for this subtable? */
1660 if (field_plen[j]) {
1661 struct trie_ctx *ctx = &trie_ctx[j];
1662 uint8_t be32ofs = ctx->be32ofs;
1664 /* Is the trie field within the current range of fields? */
1665 if (be32ofs >= ofs.start && be32ofs < ofs.end) {
1666 /* On-demand trie lookup. */
1667 if (!ctx->lookup_done) {
1668 ctx->match_plen = trie_lookup(ctx->trie, flow,
1670 ctx->lookup_done = true;
1672 /* Possible to skip the rest of the subtable if subtable's
1673 * prefix on the field is longer than what is known to match
1674 * based on the trie lookup. */
1675 if (field_plen[j] > ctx->match_plen) {
1676 /* RFC: We want the trie lookup to never result in
1677 * unwildcarding any bits that would not be unwildcarded
1678 * otherwise. Since the trie is shared by the whole
1679 * classifier, it is possible that the 'maskbits' contain
1680 * bits that are irrelevant for the partition of the
1681 * classifier relevant for the current flow. */
1683 /* Can skip if the field is already unwildcarded. */
1684 if (mask_prefix_bits_set(wc, be32ofs, ctx->maskbits)) {
1687 /* Check that the trie result will not unwildcard more bits
1688 * than this stage will. */
1689 if (ctx->maskbits <= field_plen[j]) {
1690 /* Unwildcard the bits and skip the rest. */
1691 mask_set_prefix_bits(wc, be32ofs, ctx->maskbits);
1692 /* Note: Prerequisite already unwildcarded, as the only
1693 * prerequisite of the supported trie lookup fields is
1694 * the ethertype, which is currently always
1706 /* Returns true if 'target' satisifies 'flow'/'mask', that is, if each bit
1707 * for which 'flow', for which 'mask' has a bit set, specifies a particular
1708 * value has the correct value in 'target'.
1710 * This function is equivalent to miniflow_equal_flow_in_minimask(flow,
1711 * target, mask) but it is faster because of the invariant that
1712 * flow->map and mask->masks.map are the same. */
1714 miniflow_and_mask_matches_flow(const struct miniflow *flow,
1715 const struct minimask *mask,
1716 const struct flow *target)
1718 const uint32_t *flowp = miniflow_get_u32_values(flow);
1719 const uint32_t *maskp = miniflow_get_u32_values(&mask->masks);
1720 uint32_t target_u32;
1722 FLOW_FOR_EACH_IN_MAP(target_u32, target, mask->masks.map) {
1723 if ((*flowp++ ^ target_u32) & *maskp++) {
1731 static inline struct cls_match *
1732 find_match(const struct cls_subtable *subtable, const struct flow *flow,
1735 struct cls_match *rule;
1737 HMAP_FOR_EACH_WITH_HASH (rule, hmap_node, hash, &subtable->rules) {
1738 if (miniflow_and_mask_matches_flow(&rule->flow, &subtable->mask,
1747 static struct cls_match *
1748 find_match_wc(const struct cls_subtable *subtable, const struct flow *flow,
1749 struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries,
1750 struct flow_wildcards *wc)
1752 uint32_t basis = 0, hash;
1753 struct cls_match *rule = NULL;
1757 if (OVS_UNLIKELY(!wc)) {
1758 return find_match(subtable, flow,
1759 flow_hash_in_minimask(flow, &subtable->mask, 0));
1763 /* Try to finish early by checking fields in segments. */
1764 for (i = 0; i < subtable->n_indices; i++) {
1765 struct hindex_node *inode;
1766 ofs.end = subtable->index_ofs[i];
1768 if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow,
1772 hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
1774 ofs.start = ofs.end;
1775 inode = hindex_node_with_hash(&subtable->indices[i], hash);
1777 /* No match, can stop immediately, but must fold in the mask
1778 * covered so far. */
1782 /* If we have narrowed down to a single rule already, check whether
1783 * that rule matches. If it does match, then we're done. If it does
1784 * not match, then we know that we will never get a match, but we do
1785 * not yet know how many wildcards we need to fold into 'wc' so we
1786 * continue iterating through indices to find that out. (We won't
1787 * waste time calling miniflow_and_mask_matches_flow() again because
1788 * we've set 'rule' nonnull.)
1790 * This check shows a measurable benefit with non-trivial flow tables.
1792 * (Rare) hash collisions may cause us to miss the opportunity for this
1794 if (!inode->s && !rule) {
1795 ASSIGN_CONTAINER(rule, inode - i, index_nodes);
1796 if (miniflow_and_mask_matches_flow(&rule->flow, &subtable->mask,
1802 ofs.end = FLOW_U32S;
1803 /* Trie check for the final range. */
1804 if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow, wc)) {
1808 /* Multiple potential matches exist, look for one. */
1809 hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
1811 rule = find_match(subtable, flow, hash);
1813 /* We already narrowed the matching candidates down to just 'rule',
1814 * but it didn't match. */
1817 if (!rule && subtable->ports_mask_len) {
1818 /* Ports are always part of the final range, if any.
1819 * No match was found for the ports. Use the ports trie to figure out
1820 * which ports bits to unwildcard. */
1822 ovs_be32 value, mask;
1824 mask = MINIFLOW_GET_BE32(&subtable->mask.masks, tp_src);
1825 value = ((OVS_FORCE ovs_be32 *)flow)[TP_PORTS_OFS32] & mask;
1826 trie_lookup_value(subtable->ports_trie, &value, &mbits);
1828 ((OVS_FORCE ovs_be32 *)&wc->masks)[TP_PORTS_OFS32] |=
1829 mask & htonl(~0 << (32 - mbits));
1831 ofs.start = TP_PORTS_OFS32;
1835 /* Must unwildcard all the fields, as they were looked at. */
1836 flow_wildcards_fold_minimask(wc, &subtable->mask);
1840 /* Must unwildcard the fields looked up so far, if any. */
1842 flow_wildcards_fold_minimask_range(wc, &subtable->mask, 0, ofs.start);
1847 static struct cls_match *
1848 find_equal(struct cls_subtable *subtable, const struct miniflow *flow,
1851 struct cls_match *head;
1853 HMAP_FOR_EACH_WITH_HASH (head, hmap_node, hash, &subtable->rules) {
1854 if (miniflow_equal(&head->flow, flow)) {
1861 static struct cls_match *
1862 insert_rule(struct cls_classifier *cls, struct cls_subtable *subtable,
1863 struct cls_rule *new)
1865 struct cls_match *cls_match = cls_match_alloc(new);
1866 struct cls_match *head;
1867 struct cls_match *old = NULL;
1869 uint32_t basis = 0, hash;
1870 uint8_t prev_be32ofs = 0;
1872 /* Add new node to segment indices. */
1873 for (i = 0; i < subtable->n_indices; i++) {
1874 hash = minimatch_hash_range(&new->match, prev_be32ofs,
1875 subtable->index_ofs[i], &basis);
1876 hindex_insert(&subtable->indices[i], &cls_match->index_nodes[i], hash);
1877 prev_be32ofs = subtable->index_ofs[i];
1879 hash = minimatch_hash_range(&new->match, prev_be32ofs, FLOW_U32S, &basis);
1880 head = find_equal(subtable, &new->match.flow, hash);
1882 hmap_insert(&subtable->rules, &cls_match->hmap_node, hash);
1883 list_init(&cls_match->list);
1886 /* Scan the list for the insertion point that will keep the list in
1887 * order of decreasing priority. */
1888 struct cls_match *rule;
1890 cls_match->hmap_node.hash = hash; /* Otherwise done by hmap_insert. */
1892 FOR_EACH_RULE_IN_LIST (rule, head) {
1893 if (cls_match->priority >= rule->priority) {
1895 /* 'new' is the new highest-priority flow in the list. */
1896 hmap_replace(&subtable->rules,
1897 &rule->hmap_node, &cls_match->hmap_node);
1900 if (cls_match->priority == rule->priority) {
1901 list_replace(&cls_match->list, &rule->list);
1905 list_insert(&rule->list, &cls_match->list);
1911 /* Insert 'new' at the end of the list. */
1912 list_push_back(&head->list, &cls_match->list);
1917 update_subtables_after_insertion(cls, subtable, cls_match->priority);
1919 /* Remove old node from indices. */
1920 for (i = 0; i < subtable->n_indices; i++) {
1921 hindex_remove(&subtable->indices[i], &old->index_nodes[i]);
1927 static struct cls_match *
1928 next_rule_in_list__(struct cls_match *rule)
1930 struct cls_match *next = OBJECT_CONTAINING(rule->list.next, next, list);
1934 static struct cls_match *
1935 next_rule_in_list(struct cls_match *rule)
1937 struct cls_match *next = next_rule_in_list__(rule);
1938 return next->priority < rule->priority ? next : NULL;
1941 /* A longest-prefix match tree. */
1943 uint32_t prefix; /* Prefix bits for this node, MSB first. */
1944 uint8_t nbits; /* Never zero, except for the root node. */
1945 unsigned int n_rules; /* Number of rules that have this prefix. */
1946 struct trie_node *edges[2]; /* Both NULL if leaf. */
1949 /* Max bits per node. Must fit in struct trie_node's 'prefix'.
1950 * Also tested with 16, 8, and 5 to stress the implementation. */
1951 #define TRIE_PREFIX_BITS 32
1953 /* Return at least 'plen' bits of the 'prefix', starting at bit offset 'ofs'.
1954 * Prefixes are in the network byte order, and the offset 0 corresponds to
1955 * the most significant bit of the first byte. The offset can be read as
1956 * "how many bits to skip from the start of the prefix starting at 'pr'". */
1958 raw_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
1962 pr += ofs / 32; /* Where to start. */
1963 ofs %= 32; /* How many bits to skip at 'pr'. */
1965 prefix = ntohl(*pr) << ofs; /* Get the first 32 - ofs bits. */
1966 if (plen > 32 - ofs) { /* Need more than we have already? */
1967 prefix |= ntohl(*++pr) >> (32 - ofs);
1969 /* Return with possible unwanted bits at the end. */
1973 /* Return min(TRIE_PREFIX_BITS, plen) bits of the 'prefix', starting at bit
1974 * offset 'ofs'. Prefixes are in the network byte order, and the offset 0
1975 * corresponds to the most significant bit of the first byte. The offset can
1976 * be read as "how many bits to skip from the start of the prefix starting at
1979 trie_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
1984 if (plen > TRIE_PREFIX_BITS) {
1985 plen = TRIE_PREFIX_BITS; /* Get at most TRIE_PREFIX_BITS. */
1987 /* Return with unwanted bits cleared. */
1988 return raw_get_prefix(pr, ofs, plen) & ~0u << (32 - plen);
1991 /* Return the number of equal bits in 'nbits' of 'prefix's MSBs and a 'value'
1992 * starting at "MSB 0"-based offset 'ofs'. */
1994 prefix_equal_bits(uint32_t prefix, unsigned int nbits, const ovs_be32 value[],
1997 uint64_t diff = prefix ^ raw_get_prefix(value, ofs, nbits);
1998 /* Set the bit after the relevant bits to limit the result. */
1999 return raw_clz64(diff << 32 | UINT64_C(1) << (63 - nbits));
2002 /* Return the number of equal bits in 'node' prefix and a 'prefix' of length
2003 * 'plen', starting at "MSB 0"-based offset 'ofs'. */
2005 trie_prefix_equal_bits(const struct trie_node *node, const ovs_be32 prefix[],
2006 unsigned int ofs, unsigned int plen)
2008 return prefix_equal_bits(node->prefix, MIN(node->nbits, plen - ofs),
2012 /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' can
2013 * be greater than 31. */
2015 be_get_bit_at(const ovs_be32 value[], unsigned int ofs)
2017 return (((const uint8_t *)value)[ofs / 8] >> (7 - ofs % 8)) & 1u;
2020 /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' must
2021 * be between 0 and 31, inclusive. */
2023 get_bit_at(const uint32_t prefix, unsigned int ofs)
2025 return (prefix >> (31 - ofs)) & 1u;
2028 /* Create new branch. */
2029 static struct trie_node *
2030 trie_branch_create(const ovs_be32 *prefix, unsigned int ofs, unsigned int plen,
2031 unsigned int n_rules)
2033 struct trie_node *node = xmalloc(sizeof *node);
2035 node->prefix = trie_get_prefix(prefix, ofs, plen);
2037 if (plen <= TRIE_PREFIX_BITS) {
2039 node->edges[0] = NULL;
2040 node->edges[1] = NULL;
2041 node->n_rules = n_rules;
2042 } else { /* Need intermediate nodes. */
2043 struct trie_node *subnode = trie_branch_create(prefix,
2044 ofs + TRIE_PREFIX_BITS,
2045 plen - TRIE_PREFIX_BITS,
2047 int bit = get_bit_at(subnode->prefix, 0);
2048 node->nbits = TRIE_PREFIX_BITS;
2049 node->edges[bit] = subnode;
2050 node->edges[!bit] = NULL;
2057 trie_node_destroy(struct trie_node *node)
2063 trie_destroy(struct trie_node *node)
2066 trie_destroy(node->edges[0]);
2067 trie_destroy(node->edges[1]);
2073 trie_is_leaf(const struct trie_node *trie)
2075 return !trie->edges[0] && !trie->edges[1]; /* No children. */
2079 mask_set_prefix_bits(struct flow_wildcards *wc, uint8_t be32ofs,
2082 ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
2085 for (i = 0; i < nbits / 32; i++) {
2086 mask[i] = OVS_BE32_MAX;
2089 mask[i] |= htonl(~0u << (32 - nbits % 32));
2094 mask_prefix_bits_set(const struct flow_wildcards *wc, uint8_t be32ofs,
2097 ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
2099 ovs_be32 zeroes = 0;
2101 for (i = 0; i < nbits / 32; i++) {
2105 zeroes |= ~mask[i] & htonl(~0u << (32 - nbits % 32));
2108 return !zeroes; /* All 'nbits' bits set. */
2111 static struct trie_node **
2112 trie_next_edge(struct trie_node *node, const ovs_be32 value[],
2115 return node->edges + be_get_bit_at(value, ofs);
2118 static const struct trie_node *
2119 trie_next_node(const struct trie_node *node, const ovs_be32 value[],
2122 return node->edges[be_get_bit_at(value, ofs)];
2125 /* Return the prefix mask length necessary to find the longest-prefix match for
2126 * the '*value' in the prefix tree 'node'.
2127 * '*checkbits' is set to the number of bits in the prefix mask necessary to
2128 * determine a mismatch, in case there are longer prefixes in the tree below
2129 * the one that matched.
2132 trie_lookup_value(const struct trie_node *node, const ovs_be32 value[],
2133 unsigned int *checkbits)
2135 unsigned int plen = 0, match_len = 0;
2136 const struct trie_node *prev = NULL;
2138 for (; node; prev = node, node = trie_next_node(node, value, plen)) {
2139 unsigned int eqbits;
2140 /* Check if this edge can be followed. */
2141 eqbits = prefix_equal_bits(node->prefix, node->nbits, value, plen);
2143 if (eqbits < node->nbits) { /* Mismatch, nothing more to be found. */
2144 /* Bit at offset 'plen' differed. */
2145 *checkbits = plen + 1; /* Includes the first mismatching bit. */
2148 /* Full match, check if rules exist at this prefix length. */
2149 if (node->n_rules > 0) {
2153 /* Dead end, exclude the other branch if it exists. */
2154 *checkbits = !prev || trie_is_leaf(prev) ? plen : plen + 1;
2159 trie_lookup(const struct cls_trie *trie, const struct flow *flow,
2160 unsigned int *checkbits)
2162 const struct mf_field *mf = trie->field;
2164 /* Check that current flow matches the prerequisites for the trie
2165 * field. Some match fields are used for multiple purposes, so we
2166 * must check that the trie is relevant for this flow. */
2167 if (mf_are_prereqs_ok(mf, flow)) {
2168 return trie_lookup_value(trie->root,
2169 &((ovs_be32 *)flow)[mf->flow_be32ofs],
2172 *checkbits = 0; /* Value not used in this case. */
2176 /* Returns the length of a prefix match mask for the field 'mf' in 'minimask'.
2177 * Returns the u32 offset to the miniflow data in '*miniflow_index', if
2178 * 'miniflow_index' is not NULL. */
2180 minimask_get_prefix_len(const struct minimask *minimask,
2181 const struct mf_field *mf)
2183 unsigned int nbits = 0, mask_tz = 0; /* Non-zero when end of mask seen. */
2184 uint8_t u32_ofs = mf->flow_be32ofs;
2185 uint8_t u32_end = u32_ofs + mf->n_bytes / 4;
2187 for (; u32_ofs < u32_end; ++u32_ofs) {
2189 mask = ntohl((OVS_FORCE ovs_be32)minimask_get(minimask, u32_ofs));
2191 /* Validate mask, count the mask length. */
2194 return 0; /* No bits allowed after mask ended. */
2197 if (~mask & (~mask + 1)) {
2198 return 0; /* Mask not contiguous. */
2200 mask_tz = ctz32(mask);
2201 nbits += 32 - mask_tz;
2209 * This is called only when mask prefix is known to be CIDR and non-zero.
2210 * Relies on the fact that the flow and mask have the same map, and since
2211 * the mask is CIDR, the storage for the flow field exists even if it
2212 * happened to be zeros.
2214 static const ovs_be32 *
2215 minimatch_get_prefix(const struct minimatch *match, const struct mf_field *mf)
2217 return miniflow_get_be32_values(&match->flow) +
2218 count_1bits(match->flow.map & ((UINT64_C(1) << mf->flow_be32ofs) - 1));
2221 /* Insert rule in to the prefix tree.
2222 * 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2225 trie_insert(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
2227 trie_insert_prefix(&trie->root,
2228 minimatch_get_prefix(&rule->match, trie->field), mlen);
2232 trie_insert_prefix(struct trie_node **edge, const ovs_be32 *prefix, int mlen)
2234 struct trie_node *node;
2237 /* Walk the tree. */
2238 for (; (node = *edge) != NULL;
2239 edge = trie_next_edge(node, prefix, ofs)) {
2240 unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
2242 if (eqbits < node->nbits) {
2243 /* Mismatch, new node needs to be inserted above. */
2244 int old_branch = get_bit_at(node->prefix, eqbits);
2246 /* New parent node. */
2247 *edge = trie_branch_create(prefix, ofs - eqbits, eqbits,
2248 ofs == mlen ? 1 : 0);
2250 /* Adjust old node for its new position in the tree. */
2251 node->prefix <<= eqbits;
2252 node->nbits -= eqbits;
2253 (*edge)->edges[old_branch] = node;
2255 /* Check if need a new branch for the new rule. */
2257 (*edge)->edges[!old_branch]
2258 = trie_branch_create(prefix, ofs, mlen - ofs, 1);
2262 /* Full match so far. */
2265 /* Full match at the current node, rule needs to be added here. */
2270 /* Must insert a new tree branch for the new rule. */
2271 *edge = trie_branch_create(prefix, ofs, mlen - ofs, 1);
2274 /* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2277 trie_remove(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
2279 trie_remove_prefix(&trie->root,
2280 minimatch_get_prefix(&rule->match, trie->field), mlen);
2283 /* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
2286 trie_remove_prefix(struct trie_node **root, const ovs_be32 *prefix, int mlen)
2288 struct trie_node *node;
2289 struct trie_node **edges[sizeof(union mf_value) * 8];
2290 int depth = 0, ofs = 0;
2292 /* Walk the tree. */
2293 for (edges[0] = root;
2294 (node = *edges[depth]) != NULL;
2295 edges[++depth] = trie_next_edge(node, prefix, ofs)) {
2296 unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
2298 if (eqbits < node->nbits) {
2299 /* Mismatch, nothing to be removed. This should never happen, as
2300 * only rules in the classifier are ever removed. */
2301 break; /* Log a warning. */
2303 /* Full match so far. */
2307 /* Full prefix match at the current node, remove rule here. */
2308 if (!node->n_rules) {
2309 break; /* Log a warning. */
2313 /* Check if can prune the tree. */
2314 while (!node->n_rules && !(node->edges[0] && node->edges[1])) {
2315 /* No rules and at most one child node, remove this node. */
2316 struct trie_node *next;
2317 next = node->edges[0] ? node->edges[0] : node->edges[1];
2320 if (node->nbits + next->nbits > TRIE_PREFIX_BITS) {
2321 break; /* Cannot combine. */
2323 /* Combine node with next. */
2324 next->prefix = node->prefix | next->prefix >> node->nbits;
2325 next->nbits += node->nbits;
2327 trie_node_destroy(node);
2328 /* Update the parent's edge. */
2329 *edges[depth] = next;
2330 if (next || !depth) {
2331 /* Branch not pruned or at root, nothing more to do. */
2334 node = *edges[--depth];
2339 /* Cannot go deeper. This should never happen, since only rules
2340 * that actually exist in the classifier are ever removed. */
2341 VLOG_WARN("Trying to remove non-existing rule from a prefix trie.");