2 * Copyright (c) 2009, 2010 Nicira Networks.
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"
21 #include <netinet/in.h>
22 #include "dynamic-string.h"
26 const struct cls_field cls_fields[CLS_N_FIELDS + 1] = {
27 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
28 { offsetof(struct flow, MEMBER), \
29 sizeof ((struct flow *)0)->MEMBER, \
34 { sizeof(struct flow), 0, 0, "exact" },
37 static uint32_t hash_fields(const struct flow *, int table_idx);
38 static bool equal_fields(const struct flow *, const struct flow *,
41 static int table_idx_from_wildcards(uint32_t wildcards);
42 static struct cls_rule *table_insert(struct hmap *, struct cls_rule *);
43 static struct cls_rule *insert_exact_rule(struct classifier *,
45 static struct cls_bucket *find_bucket(struct hmap *, size_t hash,
46 const struct cls_rule *);
47 static struct cls_rule *search_table(const struct hmap *table, int field_idx,
48 const struct cls_rule *);
49 static struct cls_rule *search_exact_table(const struct classifier *,
50 size_t hash, const struct flow *);
51 static bool rules_match_1wild(const struct cls_rule *fixed,
52 const struct cls_rule *wild, int field_idx);
53 static bool rules_match_2wild(const struct cls_rule *wild1,
54 const struct cls_rule *wild2, int field_idx);
56 /* Converts the flow in 'flow' into a cls_rule in 'rule', with the given
57 * 'wildcards' and 'priority'.*/
59 cls_rule_from_flow(const struct flow *flow, uint32_t wildcards,
60 unsigned int priority, struct cls_rule *rule)
63 flow_wildcards_init(&rule->wc, wildcards);
64 rule->priority = priority;
65 rule->table_idx = table_idx_from_wildcards(rule->wc.wildcards);
68 /* Converts the ofp_match in 'match' into a cls_rule in 'rule', with the given
69 * 'priority'. If 'tun_id_from_cookie' is set then the upper 32 bits of
70 * 'cookie' are stored in the rule as the tunnel ID. */
72 cls_rule_from_match(const struct ofp_match *match, unsigned int priority,
73 bool tun_id_from_cookie, uint64_t cookie,
74 struct cls_rule *rule)
77 flow_from_match(match, tun_id_from_cookie, cookie, &rule->flow, &wildcards);
78 flow_wildcards_init(&rule->wc, wildcards);
79 rule->priority = rule->wc.wildcards ? priority : UINT16_MAX;
80 rule->table_idx = table_idx_from_wildcards(rule->wc.wildcards);
83 /* Converts 'rule' to a string and returns the string. The caller must free
84 * the string (with free()). */
86 cls_rule_to_string(const struct cls_rule *rule)
88 struct ds s = DS_EMPTY_INITIALIZER;
89 ds_put_format(&s, "wildcards=%x priority=%u ",
90 rule->wc.wildcards, rule->priority);
91 flow_format(&s, &rule->flow);
95 /* Prints cls_rule 'rule', for debugging.
97 * (The output could be improved and expanded, but this was good enough to
98 * debug the classifier.) */
100 cls_rule_print(const struct cls_rule *rule)
102 printf("wildcards=%x priority=%u ", rule->wc.wildcards, rule->priority);
103 flow_print(stdout, &rule->flow);
107 /* Initializes 'cls' as a classifier that initially contains no classification
110 classifier_init(struct classifier *cls)
115 for (i = 0; i < ARRAY_SIZE(cls->tables); i++) {
116 hmap_init(&cls->tables[i]);
118 hmap_init(&cls->exact_table);
121 /* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
122 * caller's responsibility. */
124 classifier_destroy(struct classifier *cls)
127 struct cls_bucket *bucket, *next_bucket;
130 for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
131 HMAP_FOR_EACH_SAFE (bucket, next_bucket, hmap_node, tbl) {
136 hmap_destroy(&cls->exact_table);
140 /* Returns true if 'cls' does not contain any classification rules, false
143 classifier_is_empty(const struct classifier *cls)
145 return cls->n_rules == 0;
148 /* Returns the number of rules in 'classifier'. */
150 classifier_count(const struct classifier *cls)
155 /* Returns the number of rules in 'classifier' that have no wildcards. */
157 classifier_count_exact(const struct classifier *cls)
159 return hmap_count(&cls->exact_table);
162 /* Inserts 'rule' into 'cls'. Transfers ownership of 'rule' to 'cls'.
164 * If 'cls' already contains an identical rule (including wildcards, values of
165 * fixed fields, and priority), replaces the old rule by 'rule' and returns the
166 * rule that was replaced. The caller takes ownership of the returned rule and
167 * is thus responsible for freeing it, etc., as necessary.
169 * Returns NULL if 'cls' does not contain a rule with an identical key, after
170 * inserting the new rule. In this case, no rules are displaced by the new
171 * rule, even rules that cannot have any effect because the new rule matches a
172 * superset of their flows and has higher priority. */
174 classifier_insert(struct classifier *cls, struct cls_rule *rule)
176 struct cls_rule *old;
177 assert((rule->wc.wildcards == 0) == (rule->table_idx == CLS_F_IDX_EXACT));
178 old = (rule->wc.wildcards
179 ? table_insert(&cls->tables[rule->table_idx], rule)
180 : insert_exact_rule(cls, rule));
187 /* Inserts 'rule' into 'cls'. Transfers ownership of 'rule' to 'cls'.
189 * 'rule' must be an exact-match rule (rule->wc.wildcards must be 0) and 'cls'
190 * must not contain any rule with an identical key. */
192 classifier_insert_exact(struct classifier *cls, struct cls_rule *rule)
194 hmap_insert(&cls->exact_table, &rule->node.hmap,
195 flow_hash(&rule->flow, 0));
199 /* Removes 'rule' from 'cls'. It is caller's responsibility to free 'rule', if
200 * this is desirable. */
202 classifier_remove(struct classifier *cls, struct cls_rule *rule)
204 if (rule->wc.wildcards) {
205 /* Remove 'rule' from bucket. If that empties the bucket, remove the
206 * bucket from its table. */
207 struct hmap *table = &cls->tables[rule->table_idx];
208 struct list *rules = list_remove(&rule->node.list);
209 if (list_is_empty(rules)) {
210 /* This code is a little tricky. list_remove() returns the list
211 * element just after the one removed. Since the list is now
212 * empty, this will be the address of the 'rules' member of the
213 * bucket that was just emptied, so pointer arithmetic (via
214 * CONTAINER_OF) can find that bucket. */
215 struct cls_bucket *bucket;
216 bucket = CONTAINER_OF(rules, struct cls_bucket, rules);
217 hmap_remove(table, &bucket->hmap_node);
221 /* Remove 'rule' from cls->exact_table. */
222 hmap_remove(&cls->exact_table, &rule->node.hmap);
227 /* Finds and returns the highest-priority rule in 'cls' that matches 'flow'.
228 * Returns a null pointer if no rules in 'cls' match 'flow'. If multiple rules
229 * of equal priority match 'flow', returns one arbitrarily.
231 * (When multiple rules of equal priority happen to fall into the same bucket,
232 * rules added more recently take priority over rules added less recently, but
233 * this is subject to change and should not be depended upon.) */
235 classifier_lookup(const struct classifier *cls, const struct flow *flow)
237 struct cls_rule *rule = classifier_lookup_exact(cls, flow);
239 rule = classifier_lookup_wild(cls, flow);
245 classifier_lookup_exact(const struct classifier *cls, const struct flow *flow)
247 return (!hmap_is_empty(&cls->exact_table)
248 ? search_exact_table(cls, flow_hash(flow, 0), flow)
253 classifier_lookup_wild(const struct classifier *cls, const struct flow *flow)
255 struct cls_rule *best = NULL;
256 if (cls->n_rules > hmap_count(&cls->exact_table)) {
257 struct cls_rule target;
260 cls_rule_from_flow(flow, 0, 0, &target);
261 for (i = 0; i < CLS_N_FIELDS; i++) {
262 struct cls_rule *rule = search_table(&cls->tables[i], i, &target);
263 if (rule && (!best || rule->priority > best->priority)) {
272 classifier_find_rule_exactly(const struct classifier *cls,
273 const struct flow *target, uint32_t wildcards,
274 unsigned int priority)
276 struct cls_bucket *bucket;
281 /* Ignores 'priority'. */
282 return search_exact_table(cls, flow_hash(target, 0), target);
285 assert(wildcards == (wildcards & OVSFW_ALL));
286 table_idx = table_idx_from_wildcards(wildcards);
287 hash = hash_fields(target, table_idx);
288 HMAP_FOR_EACH_WITH_HASH (bucket, hmap_node, hash,
289 &cls->tables[table_idx]) {
290 if (equal_fields(&bucket->fixed, target, table_idx)) {
291 struct cls_rule *pos;
292 LIST_FOR_EACH (pos, node.list, &bucket->rules) {
293 if (pos->priority < priority) {
295 } else if (pos->priority == priority &&
296 pos->wc.wildcards == wildcards &&
297 flow_equal(target, &pos->flow)) {
306 /* Checks if the flow defined by 'target' with 'wildcards' at 'priority'
307 * overlaps with any other rule at the same priority in the classifier.
308 * Two rules are considered overlapping if a packet could match both. */
310 classifier_rule_overlaps(const struct classifier *cls,
311 const struct flow *target, uint32_t wildcards,
312 unsigned int priority)
314 struct cls_rule target_rule;
315 const struct hmap *tbl;
318 return search_exact_table(cls, flow_hash(target, 0), target) ?
322 cls_rule_from_flow(target, wildcards, priority, &target_rule);
324 for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
325 struct cls_bucket *bucket;
327 HMAP_FOR_EACH (bucket, hmap_node, tbl) {
328 struct cls_rule *rule;
330 LIST_FOR_EACH (rule, node.list, &bucket->rules) {
331 if (rule->priority == priority
332 && rules_match_2wild(rule, &target_rule, 0)) {
342 /* Ignores target->priority.
344 * 'callback' is allowed to delete the rule that is passed as its argument, but
345 * it must not delete (or move) any other rules in 'cls' that are in the same
346 * table as the argument rule. Two rules are in the same table if their
347 * cls_rule structs have the same table_idx; as a special case, a rule with
348 * wildcards and an exact-match rule will never be in the same table. */
350 classifier_for_each_match(const struct classifier *cls,
351 const struct cls_rule *target,
352 int include, cls_cb_func *callback, void *aux)
354 if (include & CLS_INC_WILD) {
355 const struct hmap *table;
357 for (table = &cls->tables[0]; table < &cls->tables[CLS_N_FIELDS];
359 struct cls_bucket *bucket, *next_bucket;
361 HMAP_FOR_EACH_SAFE (bucket, next_bucket, hmap_node, table) {
362 /* XXX there is a bit of room for optimization here based on
363 * rejecting entire buckets on their fixed fields, but it will
364 * only be worthwhile for big buckets (which we hope we won't
365 * get anyway, but...) */
366 struct cls_rule *prev_rule, *rule;
368 /* We can't just use LIST_FOR_EACH_SAFE here because, if the
369 * callback deletes the last rule in the bucket, then the
370 * bucket itself will be destroyed. The bucket contains the
371 * list head so that's a use-after-free error. */
373 LIST_FOR_EACH (rule, node.list, &bucket->rules) {
374 if (rules_match_1wild(rule, target, 0)) {
376 callback(prev_rule, aux);
382 callback(prev_rule, aux);
388 if (include & CLS_INC_EXACT) {
389 if (target->wc.wildcards) {
390 struct cls_rule *rule, *next_rule;
392 HMAP_FOR_EACH_SAFE (rule, next_rule, node.hmap,
394 if (rules_match_1wild(rule, target, 0)) {
399 /* Optimization: there can be at most one match in the exact
401 size_t hash = flow_hash(&target->flow, 0);
402 struct cls_rule *rule = search_exact_table(cls, hash,
411 /* 'callback' is allowed to delete the rule that is passed as its argument, but
412 * it must not delete (or move) any other rules in 'cls' that are in the same
413 * table as the argument rule. Two rules are in the same table if their
414 * cls_rule structs have the same table_idx; as a special case, a rule with
415 * wildcards and an exact-match rule will never be in the same table.
417 * If 'include' is CLS_INC_EXACT then CLASSIFIER_FOR_EACH_EXACT_RULE(_SAFE) is
418 * probably easier to use. */
420 classifier_for_each(const struct classifier *cls, int include,
421 void (*callback)(struct cls_rule *, void *aux),
424 if (include & CLS_INC_WILD) {
425 const struct hmap *tbl;
427 for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
428 struct cls_bucket *bucket, *next_bucket;
430 HMAP_FOR_EACH_SAFE (bucket, next_bucket, hmap_node, tbl) {
431 struct cls_rule *prev_rule, *rule;
433 /* We can't just use LIST_FOR_EACH_SAFE here because, if the
434 * callback deletes the last rule in the bucket, then the
435 * bucket itself will be destroyed. The bucket contains the
436 * list head so that's a use-after-free error. */
438 LIST_FOR_EACH (rule, node.list, &bucket->rules) {
440 callback(prev_rule, aux);
445 callback(prev_rule, aux);
451 if (include & CLS_INC_EXACT) {
452 struct cls_rule *rule, *next_rule;
454 HMAP_FOR_EACH_SAFE (rule, next_rule, node.hmap, &cls->exact_table) {
460 static struct cls_bucket *create_bucket(struct hmap *, size_t hash,
461 const struct flow *fixed);
462 static struct cls_rule *bucket_insert(struct cls_bucket *, struct cls_rule *);
464 static inline bool equal_bytes(const void *, const void *, size_t n);
466 /* Returns a hash computed across the fields in 'flow' whose field indexes
467 * (CLS_F_IDX_*) are less than 'table_idx'. (If 'table_idx' is
468 * CLS_F_IDX_EXACT, hashes all the fields in 'flow'). */
470 hash_fields(const struct flow *flow, int table_idx)
472 /* I just know I'm going to hell for writing code this way.
474 * GCC generates pretty good code here, with only a single taken
475 * conditional jump per execution. Now the question is, would we be better
476 * off marking this function ALWAYS_INLINE and writing a wrapper that
477 * switches on the value of 'table_idx' to get rid of all the conditional
478 * jumps entirely (except for one in the wrapper)? Honestly I really,
479 * really hope that it doesn't matter in practice.
481 * We could do better by calculating hashes incrementally, instead of
482 * starting over from the top each time. But that would be even uglier. */
487 a = b = c = 0xdeadbeef + table_idx;
490 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
491 if (table_idx == CLS_F_IDX_##NAME) { \
493 memset((uint8_t *) tmp + n, 0, sizeof tmp - n); \
496 const size_t size = sizeof flow->MEMBER; \
497 const uint8_t *p1 = (const uint8_t *) &flow->MEMBER; \
498 const size_t p1_size = MIN(sizeof tmp - n, size); \
499 const uint8_t *p2 = p1 + p1_size; \
500 const size_t p2_size = size - p1_size; \
502 /* Append to 'tmp' as much data as will fit. */ \
503 memcpy((uint8_t *) tmp + n, p1, p1_size); \
506 /* If 'tmp' is full, mix. */ \
507 if (n == sizeof tmp) { \
515 /* Append to 'tmp' any data that didn't fit. */ \
516 memcpy(tmp, p2, p2_size); \
530 /* Compares the fields in 'a' and 'b' whose field indexes (CLS_F_IDX_*) are
531 * less than 'table_idx'. (If 'table_idx' is CLS_F_IDX_EXACT, compares all the
532 * fields in 'a' and 'b').
534 * Returns true if all the compared fields are equal, false otherwise. */
536 equal_fields(const struct flow *a, const struct flow *b, int table_idx)
538 /* XXX The generated code could be better here. */
539 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
540 if (table_idx == CLS_F_IDX_##NAME) { \
542 } else if (!equal_bytes(&a->MEMBER, &b->MEMBER, sizeof a->MEMBER)) { \
552 table_idx_from_wildcards(uint32_t wildcards)
555 return CLS_F_IDX_EXACT;
557 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
558 if (wildcards & WILDCARDS) { \
559 return CLS_F_IDX_##NAME; \
566 /* Inserts 'rule' into 'table'. Returns the rule, if any, that was displaced
567 * in favor of 'rule'. */
568 static struct cls_rule *
569 table_insert(struct hmap *table, struct cls_rule *rule)
571 struct cls_bucket *bucket;
574 hash = hash_fields(&rule->flow, rule->table_idx);
575 bucket = find_bucket(table, hash, rule);
577 bucket = create_bucket(table, hash, &rule->flow);
580 return bucket_insert(bucket, rule);
583 /* Inserts 'rule' into 'bucket', given that 'field' is the first wildcarded
586 * Returns the rule, if any, that was displaced in favor of 'rule'. */
587 static struct cls_rule *
588 bucket_insert(struct cls_bucket *bucket, struct cls_rule *rule)
590 struct cls_rule *pos;
591 LIST_FOR_EACH (pos, node.list, &bucket->rules) {
592 if (pos->priority == rule->priority) {
593 if (pos->wc.wildcards == rule->wc.wildcards
594 && rules_match_1wild(pos, rule, rule->table_idx))
596 list_replace(&rule->node.list, &pos->node.list);
599 } else if (pos->priority < rule->priority) {
603 list_insert(&pos->node.list, &rule->node.list);
607 static struct cls_rule *
608 insert_exact_rule(struct classifier *cls, struct cls_rule *rule)
610 struct cls_rule *old_rule;
613 hash = flow_hash(&rule->flow, 0);
614 old_rule = search_exact_table(cls, hash, &rule->flow);
616 hmap_remove(&cls->exact_table, &old_rule->node.hmap);
618 hmap_insert(&cls->exact_table, &rule->node.hmap, hash);
622 /* Returns the bucket in 'table' that has the given 'hash' and the same fields
623 * as 'rule->flow' (up to 'rule->table_idx'), or a null pointer if no bucket
625 static struct cls_bucket *
626 find_bucket(struct hmap *table, size_t hash, const struct cls_rule *rule)
628 struct cls_bucket *bucket;
629 HMAP_FOR_EACH_WITH_HASH (bucket, hmap_node, hash, table) {
630 if (equal_fields(&bucket->fixed, &rule->flow, rule->table_idx)) {
637 /* Creates a bucket and inserts it in 'table' with the given 'hash' and 'fixed'
638 * values. Returns the new bucket. */
639 static struct cls_bucket *
640 create_bucket(struct hmap *table, size_t hash, const struct flow *fixed)
642 struct cls_bucket *bucket = xmalloc(sizeof *bucket);
643 list_init(&bucket->rules);
644 bucket->fixed = *fixed;
645 hmap_insert(table, &bucket->hmap_node, hash);
649 /* Returns true if the 'n' bytes in 'a' and 'b' are equal, false otherwise. */
650 static inline bool ALWAYS_INLINE
651 equal_bytes(const void *a, const void *b, size_t n)
654 /* For some reason GCC generates stupid code for memcmp() of small
655 * constant integer lengths. Help it out.
657 * This function is always inlined, and it is always called with 'n' as a
658 * compile-time constant, so the switch statement gets optimized out and
659 * this whole function just expands to an instruction or two. */
662 return *(uint8_t *) a == *(uint8_t *) b;
665 return *(uint16_t *) a == *(uint16_t *) b;
668 return *(uint32_t *) a == *(uint32_t *) b;
671 return (*(uint32_t *) a == *(uint32_t *) b
672 && ((uint16_t *) a)[2] == ((uint16_t *) b)[2]);
678 /* I hope GCC is smarter on your platform. */
679 return !memcmp(a, b, n);
683 /* Returns the 32-bit unsigned integer at 'p'. */
684 static inline uint32_t
685 read_uint32(const void *p)
687 /* GCC optimizes this into a single machine instruction on x86. */
689 memcpy(&x, p, sizeof x);
693 /* Compares the specified field in 'a' and 'b'. Returns true if the fields are
694 * equal, or if the ofp_match wildcard bits in 'wildcards' are set such that
695 * non-equal values may be ignored. 'nw_src_mask' and 'nw_dst_mask' must be
696 * those that would be set for 'wildcards' by cls_rule_set_masks().
698 * The compared field is the one with wildcard bit or bits 'field_wc', offset
699 * 'rule_ofs' within cls_rule's "fields" member, and length 'len', in bytes. */
700 static inline bool ALWAYS_INLINE
701 field_matches(const struct flow *a_, const struct flow *b_,
702 uint32_t wildcards, uint32_t nw_src_mask, uint32_t nw_dst_mask,
703 uint32_t field_wc, int ofs, int len)
705 /* This function is always inlined, and it is always called with 'field_wc'
706 * as a compile-time constant, so the "if" conditionals here generate no
708 const void *a = (const uint8_t *) a_ + ofs;
709 const void *b = (const uint8_t *) b_ + ofs;
710 if (!(field_wc & (field_wc - 1))) {
711 /* Handle all the single-bit wildcard cases. */
712 return wildcards & field_wc || equal_bytes(a, b, len);
713 } else if (field_wc == OFPFW_NW_SRC_MASK ||
714 field_wc == OFPFW_NW_DST_MASK) {
715 uint32_t a_ip = read_uint32(a);
716 uint32_t b_ip = read_uint32(b);
717 uint32_t mask = (field_wc == OFPFW_NW_SRC_MASK
718 ? nw_src_mask : nw_dst_mask);
719 return ((a_ip ^ b_ip) & mask) == 0;
725 /* Returns true if 'a' and 'b' match, ignoring fields for which the wildcards
726 * in 'wildcards' are set. 'nw_src_mask' and 'nw_dst_mask' must be those that
727 * would be set for 'wildcards' by cls_rule_set_masks(). 'field_idx' is the
728 * index of the first field to be compared; fields before 'field_idx' are
729 * assumed to match. (Always returns true if 'field_idx' is CLS_N_FIELDS.) */
731 rules_match(const struct cls_rule *a, const struct cls_rule *b,
732 uint32_t wildcards, uint32_t nw_src_mask, uint32_t nw_dst_mask,
735 /* This is related to Duff's device (see
736 * http://en.wikipedia.org/wiki/Duff's_device). */
738 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
739 case CLS_F_IDX_##NAME: \
740 if (!field_matches(&a->flow, &b->flow, \
741 wildcards, nw_src_mask, nw_dst_mask, \
742 WILDCARDS, offsetof(struct flow, MEMBER), \
743 sizeof a->flow.MEMBER)) { \
753 /* Returns true if 'fixed' and 'wild' match. All fields in 'fixed' must have
754 * fixed values; 'wild' may contain wildcards.
756 * 'field_idx' is the index of the first field to be compared; fields before
757 * 'field_idx' are assumed to match. Always returns true if 'field_idx' is
760 rules_match_1wild(const struct cls_rule *fixed, const struct cls_rule *wild,
763 return rules_match(fixed, wild, wild->wc.wildcards, wild->wc.nw_src_mask,
764 wild->wc.nw_dst_mask, field_idx);
767 /* Returns true if 'wild1' and 'wild2' match, that is, if their fields
768 * are equal modulo wildcards in 'wild1' or 'wild2'.
770 * 'field_idx' is the index of the first field to be compared; fields before
771 * 'field_idx' are assumed to match. Always returns true if 'field_idx' is
774 rules_match_2wild(const struct cls_rule *wild1, const struct cls_rule *wild2,
777 return rules_match(wild1, wild2,
778 wild1->wc.wildcards | wild2->wc.wildcards,
779 wild1->wc.nw_src_mask & wild2->wc.nw_src_mask,
780 wild1->wc.nw_dst_mask & wild2->wc.nw_dst_mask,
784 /* Searches 'bucket' for a rule that matches 'target'. Returns the
785 * highest-priority match, if one is found, or a null pointer if there is no
788 * 'field_idx' must be the index of the first wildcarded field in 'bucket'. */
789 static struct cls_rule *
790 search_bucket(struct cls_bucket *bucket, int field_idx,
791 const struct cls_rule *target)
793 struct cls_rule *pos;
795 if (!equal_fields(&bucket->fixed, &target->flow, field_idx)) {
799 LIST_FOR_EACH (pos, node.list, &bucket->rules) {
800 if (rules_match_1wild(target, pos, field_idx)) {
807 /* Searches 'table' for a rule that matches 'target'. Returns the
808 * highest-priority match, if one is found, or a null pointer if there is no
811 * 'field_idx' must be the index of the first wildcarded field in 'table'. */
812 static struct cls_rule *
813 search_table(const struct hmap *table, int field_idx,
814 const struct cls_rule *target)
816 struct cls_bucket *bucket;
818 switch (hmap_count(table)) {
819 /* In these special cases there's no need to hash. */
823 bucket = CONTAINER_OF(hmap_first(table), struct cls_bucket, hmap_node);
824 return search_bucket(bucket, field_idx, target);
827 HMAP_FOR_EACH_WITH_HASH (bucket, hmap_node,
828 hash_fields(&target->flow, field_idx), table) {
829 struct cls_rule *rule = search_bucket(bucket, field_idx, target);
837 static struct cls_rule *
838 search_exact_table(const struct classifier *cls, size_t hash,
839 const struct flow *target)
841 struct cls_rule *rule;
843 HMAP_FOR_EACH_WITH_HASH (rule, node.hmap, hash, &cls->exact_table) {
844 if (flow_equal(&rule->flow, target)) {