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 /* Removes 'rule' from 'cls'. It is caller's responsibility to free 'rule', if
188 * this is desirable. */
190 classifier_remove(struct classifier *cls, struct cls_rule *rule)
192 if (rule->wc.wildcards) {
193 /* Remove 'rule' from bucket. If that empties the bucket, remove the
194 * bucket from its table. */
195 struct hmap *table = &cls->tables[rule->table_idx];
196 struct list *rules = list_remove(&rule->node.list);
197 if (list_is_empty(rules)) {
198 /* This code is a little tricky. list_remove() returns the list
199 * element just after the one removed. Since the list is now
200 * empty, this will be the address of the 'rules' member of the
201 * bucket that was just emptied, so pointer arithmetic (via
202 * CONTAINER_OF) can find that bucket. */
203 struct cls_bucket *bucket;
204 bucket = CONTAINER_OF(rules, struct cls_bucket, rules);
205 hmap_remove(table, &bucket->hmap_node);
209 /* Remove 'rule' from cls->exact_table. */
210 hmap_remove(&cls->exact_table, &rule->node.hmap);
215 static struct cls_rule *
216 classifier_lookup_exact(const struct classifier *cls, const struct flow *flow)
218 return (!hmap_is_empty(&cls->exact_table)
219 ? search_exact_table(cls, flow_hash(flow, 0), flow)
223 static struct cls_rule *
224 classifier_lookup_wild(const struct classifier *cls, const struct flow *flow)
226 struct cls_rule *best = NULL;
227 if (cls->n_rules > hmap_count(&cls->exact_table)) {
228 struct cls_rule target;
231 cls_rule_from_flow(flow, 0, 0, &target);
232 for (i = 0; i < CLS_N_FIELDS; i++) {
233 struct cls_rule *rule = search_table(&cls->tables[i], i, &target);
234 if (rule && (!best || rule->priority > best->priority)) {
242 /* Finds and returns the highest-priority rule in 'cls' that matches 'flow'.
243 * Returns a null pointer if no rules in 'cls' match 'flow'. If multiple rules
244 * of equal priority match 'flow', returns one arbitrarily.
246 * (When multiple rules of equal priority happen to fall into the same bucket,
247 * rules added more recently take priority over rules added less recently, but
248 * this is subject to change and should not be depended upon.) */
250 classifier_lookup(const struct classifier *cls, const struct flow *flow,
253 if (include & CLS_INC_EXACT) {
254 struct cls_rule *rule = classifier_lookup_exact(cls, flow);
260 if (include & CLS_INC_WILD) {
261 return classifier_lookup_wild(cls, flow);
268 classifier_find_rule_exactly(const struct classifier *cls,
269 const struct cls_rule *target)
271 struct cls_bucket *bucket;
275 if (!target->wc.wildcards) {
276 /* Ignores 'target->priority'. */
277 return search_exact_table(cls, flow_hash(&target->flow, 0),
281 assert(target->wc.wildcards == (target->wc.wildcards & OVSFW_ALL));
282 table_idx = table_idx_from_wildcards(target->wc.wildcards);
283 hash = hash_fields(&target->flow, table_idx);
284 HMAP_FOR_EACH_WITH_HASH (bucket, hmap_node, hash,
285 &cls->tables[table_idx]) {
286 if (equal_fields(&bucket->fixed, &target->flow, table_idx)) {
287 struct cls_rule *pos;
288 LIST_FOR_EACH (pos, node.list, &bucket->rules) {
289 if (pos->priority < target->priority) {
291 } else if (pos->priority == target->priority &&
292 pos->wc.wildcards == target->wc.wildcards &&
293 flow_equal(&target->flow, &pos->flow)) {
302 /* Checks if the flow defined by 'target' with 'wildcards' at 'priority'
303 * overlaps with any other rule at the same priority in the classifier.
304 * Two rules are considered overlapping if a packet could match both. */
306 classifier_rule_overlaps(const struct classifier *cls,
307 const struct flow *target, uint32_t wildcards,
308 unsigned int priority)
310 struct cls_rule target_rule;
311 const struct hmap *tbl;
314 return search_exact_table(cls, flow_hash(target, 0), target) ?
318 cls_rule_from_flow(target, wildcards, priority, &target_rule);
320 for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
321 struct cls_bucket *bucket;
323 HMAP_FOR_EACH (bucket, hmap_node, tbl) {
324 struct cls_rule *rule;
326 LIST_FOR_EACH (rule, node.list, &bucket->rules) {
327 if (rule->priority == priority
328 && rules_match_2wild(rule, &target_rule, 0)) {
338 /* Ignores target->priority.
340 * 'callback' is allowed to delete the rule that is passed as its argument, but
341 * it must not delete (or move) any other rules in 'cls' that are in the same
342 * table as the argument rule. Two rules are in the same table if their
343 * cls_rule structs have the same table_idx; as a special case, a rule with
344 * wildcards and an exact-match rule will never be in the same table. */
346 classifier_for_each_match(const struct classifier *cls,
347 const struct cls_rule *target,
348 int include, cls_cb_func *callback, void *aux)
350 if (include & CLS_INC_WILD) {
351 const struct hmap *table;
353 for (table = &cls->tables[0]; table < &cls->tables[CLS_N_FIELDS];
355 struct cls_bucket *bucket, *next_bucket;
357 HMAP_FOR_EACH_SAFE (bucket, next_bucket, hmap_node, table) {
358 /* XXX there is a bit of room for optimization here based on
359 * rejecting entire buckets on their fixed fields, but it will
360 * only be worthwhile for big buckets (which we hope we won't
361 * get anyway, but...) */
362 struct cls_rule *prev_rule, *rule;
364 /* We can't just use LIST_FOR_EACH_SAFE here because, if the
365 * callback deletes the last rule in the bucket, then the
366 * bucket itself will be destroyed. The bucket contains the
367 * list head so that's a use-after-free error. */
369 LIST_FOR_EACH (rule, node.list, &bucket->rules) {
370 if (rules_match_1wild(rule, target, 0)) {
372 callback(prev_rule, aux);
378 callback(prev_rule, aux);
384 if (include & CLS_INC_EXACT) {
385 if (target->wc.wildcards) {
386 struct cls_rule *rule, *next_rule;
388 HMAP_FOR_EACH_SAFE (rule, next_rule, node.hmap,
390 if (rules_match_1wild(rule, target, 0)) {
395 /* Optimization: there can be at most one match in the exact
397 size_t hash = flow_hash(&target->flow, 0);
398 struct cls_rule *rule = search_exact_table(cls, hash,
407 /* 'callback' is allowed to delete the rule that is passed as its argument, but
408 * it must not delete (or move) any other rules in 'cls' that are in the same
409 * table as the argument rule. Two rules are in the same table if their
410 * cls_rule structs have the same table_idx; as a special case, a rule with
411 * wildcards and an exact-match rule will never be in the same table.
413 * If 'include' is CLS_INC_EXACT then CLASSIFIER_FOR_EACH_EXACT_RULE(_SAFE) is
414 * probably easier to use. */
416 classifier_for_each(const struct classifier *cls, int include,
417 void (*callback)(struct cls_rule *, void *aux),
420 if (include & CLS_INC_WILD) {
421 const struct hmap *tbl;
423 for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
424 struct cls_bucket *bucket, *next_bucket;
426 HMAP_FOR_EACH_SAFE (bucket, next_bucket, hmap_node, tbl) {
427 struct cls_rule *prev_rule, *rule;
429 /* We can't just use LIST_FOR_EACH_SAFE here because, if the
430 * callback deletes the last rule in the bucket, then the
431 * bucket itself will be destroyed. The bucket contains the
432 * list head so that's a use-after-free error. */
434 LIST_FOR_EACH (rule, node.list, &bucket->rules) {
436 callback(prev_rule, aux);
441 callback(prev_rule, aux);
447 if (include & CLS_INC_EXACT) {
448 struct cls_rule *rule, *next_rule;
450 HMAP_FOR_EACH_SAFE (rule, next_rule, node.hmap, &cls->exact_table) {
456 static struct cls_bucket *create_bucket(struct hmap *, size_t hash,
457 const struct flow *fixed);
458 static struct cls_rule *bucket_insert(struct cls_bucket *, struct cls_rule *);
460 static inline bool equal_bytes(const void *, const void *, size_t n);
462 /* Returns a hash computed across the fields in 'flow' whose field indexes
463 * (CLS_F_IDX_*) are less than 'table_idx'. (If 'table_idx' is
464 * CLS_F_IDX_EXACT, hashes all the fields in 'flow'). */
466 hash_fields(const struct flow *flow, int table_idx)
468 /* I just know I'm going to hell for writing code this way.
470 * GCC generates pretty good code here, with only a single taken
471 * conditional jump per execution. Now the question is, would we be better
472 * off marking this function ALWAYS_INLINE and writing a wrapper that
473 * switches on the value of 'table_idx' to get rid of all the conditional
474 * jumps entirely (except for one in the wrapper)? Honestly I really,
475 * really hope that it doesn't matter in practice.
477 * We could do better by calculating hashes incrementally, instead of
478 * starting over from the top each time. But that would be even uglier. */
483 a = b = c = 0xdeadbeef + table_idx;
486 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
487 if (table_idx == CLS_F_IDX_##NAME) { \
489 memset((uint8_t *) tmp + n, 0, sizeof tmp - n); \
492 const size_t size = sizeof flow->MEMBER; \
493 const uint8_t *p1 = (const uint8_t *) &flow->MEMBER; \
494 const size_t p1_size = MIN(sizeof tmp - n, size); \
495 const uint8_t *p2 = p1 + p1_size; \
496 const size_t p2_size = size - p1_size; \
498 /* Append to 'tmp' as much data as will fit. */ \
499 memcpy((uint8_t *) tmp + n, p1, p1_size); \
502 /* If 'tmp' is full, mix. */ \
503 if (n == sizeof tmp) { \
511 /* Append to 'tmp' any data that didn't fit. */ \
512 memcpy(tmp, p2, p2_size); \
526 /* Compares the fields in 'a' and 'b' whose field indexes (CLS_F_IDX_*) are
527 * less than 'table_idx'. (If 'table_idx' is CLS_F_IDX_EXACT, compares all the
528 * fields in 'a' and 'b').
530 * Returns true if all the compared fields are equal, false otherwise. */
532 equal_fields(const struct flow *a, const struct flow *b, int table_idx)
534 /* XXX The generated code could be better here. */
535 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
536 if (table_idx == CLS_F_IDX_##NAME) { \
538 } else if (!equal_bytes(&a->MEMBER, &b->MEMBER, sizeof a->MEMBER)) { \
548 table_idx_from_wildcards(uint32_t wildcards)
551 return CLS_F_IDX_EXACT;
553 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
554 if (wildcards & WILDCARDS) { \
555 return CLS_F_IDX_##NAME; \
562 /* Inserts 'rule' into 'table'. Returns the rule, if any, that was displaced
563 * in favor of 'rule'. */
564 static struct cls_rule *
565 table_insert(struct hmap *table, struct cls_rule *rule)
567 struct cls_bucket *bucket;
570 hash = hash_fields(&rule->flow, rule->table_idx);
571 bucket = find_bucket(table, hash, rule);
573 bucket = create_bucket(table, hash, &rule->flow);
576 return bucket_insert(bucket, rule);
579 /* Inserts 'rule' into 'bucket', given that 'field' is the first wildcarded
582 * Returns the rule, if any, that was displaced in favor of 'rule'. */
583 static struct cls_rule *
584 bucket_insert(struct cls_bucket *bucket, struct cls_rule *rule)
586 struct cls_rule *pos;
587 LIST_FOR_EACH (pos, node.list, &bucket->rules) {
588 if (pos->priority == rule->priority) {
589 if (pos->wc.wildcards == rule->wc.wildcards
590 && rules_match_1wild(pos, rule, rule->table_idx))
592 list_replace(&rule->node.list, &pos->node.list);
595 } else if (pos->priority < rule->priority) {
599 list_insert(&pos->node.list, &rule->node.list);
603 static struct cls_rule *
604 insert_exact_rule(struct classifier *cls, struct cls_rule *rule)
606 struct cls_rule *old_rule;
609 hash = flow_hash(&rule->flow, 0);
610 old_rule = search_exact_table(cls, hash, &rule->flow);
612 hmap_remove(&cls->exact_table, &old_rule->node.hmap);
614 hmap_insert(&cls->exact_table, &rule->node.hmap, hash);
618 /* Returns the bucket in 'table' that has the given 'hash' and the same fields
619 * as 'rule->flow' (up to 'rule->table_idx'), or a null pointer if no bucket
621 static struct cls_bucket *
622 find_bucket(struct hmap *table, size_t hash, const struct cls_rule *rule)
624 struct cls_bucket *bucket;
625 HMAP_FOR_EACH_WITH_HASH (bucket, hmap_node, hash, table) {
626 if (equal_fields(&bucket->fixed, &rule->flow, rule->table_idx)) {
633 /* Creates a bucket and inserts it in 'table' with the given 'hash' and 'fixed'
634 * values. Returns the new bucket. */
635 static struct cls_bucket *
636 create_bucket(struct hmap *table, size_t hash, const struct flow *fixed)
638 struct cls_bucket *bucket = xmalloc(sizeof *bucket);
639 list_init(&bucket->rules);
640 bucket->fixed = *fixed;
641 hmap_insert(table, &bucket->hmap_node, hash);
645 /* Returns true if the 'n' bytes in 'a' and 'b' are equal, false otherwise. */
646 static inline bool ALWAYS_INLINE
647 equal_bytes(const void *a, const void *b, size_t n)
650 /* For some reason GCC generates stupid code for memcmp() of small
651 * constant integer lengths. Help it out.
653 * This function is always inlined, and it is always called with 'n' as a
654 * compile-time constant, so the switch statement gets optimized out and
655 * this whole function just expands to an instruction or two. */
658 return *(uint8_t *) a == *(uint8_t *) b;
661 return *(uint16_t *) a == *(uint16_t *) b;
664 return *(uint32_t *) a == *(uint32_t *) b;
667 return (*(uint32_t *) a == *(uint32_t *) b
668 && ((uint16_t *) a)[2] == ((uint16_t *) b)[2]);
674 /* I hope GCC is smarter on your platform. */
675 return !memcmp(a, b, n);
679 /* Returns the 32-bit unsigned integer at 'p'. */
680 static inline uint32_t
681 read_uint32(const void *p)
683 /* GCC optimizes this into a single machine instruction on x86. */
685 memcpy(&x, p, sizeof x);
689 /* Compares the specified field in 'a' and 'b'. Returns true if the fields are
690 * equal, or if the ofp_match wildcard bits in 'wildcards' are set such that
691 * non-equal values may be ignored. 'nw_src_mask' and 'nw_dst_mask' must be
692 * those that would be set for 'wildcards' by cls_rule_set_masks().
694 * The compared field is the one with wildcard bit or bits 'field_wc', offset
695 * 'rule_ofs' within cls_rule's "fields" member, and length 'len', in bytes. */
696 static inline bool ALWAYS_INLINE
697 field_matches(const struct flow *a_, const struct flow *b_,
698 uint32_t wildcards, uint32_t nw_src_mask, uint32_t nw_dst_mask,
699 uint32_t field_wc, int ofs, int len)
701 /* This function is always inlined, and it is always called with 'field_wc'
702 * as a compile-time constant, so the "if" conditionals here generate no
704 const void *a = (const uint8_t *) a_ + ofs;
705 const void *b = (const uint8_t *) b_ + ofs;
706 if (!(field_wc & (field_wc - 1))) {
707 /* Handle all the single-bit wildcard cases. */
708 return wildcards & field_wc || equal_bytes(a, b, len);
709 } else if (field_wc == OFPFW_NW_SRC_MASK ||
710 field_wc == OFPFW_NW_DST_MASK) {
711 uint32_t a_ip = read_uint32(a);
712 uint32_t b_ip = read_uint32(b);
713 uint32_t mask = (field_wc == OFPFW_NW_SRC_MASK
714 ? nw_src_mask : nw_dst_mask);
715 return ((a_ip ^ b_ip) & mask) == 0;
721 /* Returns true if 'a' and 'b' match, ignoring fields for which the wildcards
722 * in 'wildcards' are set. 'nw_src_mask' and 'nw_dst_mask' must be those that
723 * would be set for 'wildcards' by cls_rule_set_masks(). 'field_idx' is the
724 * index of the first field to be compared; fields before 'field_idx' are
725 * assumed to match. (Always returns true if 'field_idx' is CLS_N_FIELDS.) */
727 rules_match(const struct cls_rule *a, const struct cls_rule *b,
728 uint32_t wildcards, uint32_t nw_src_mask, uint32_t nw_dst_mask,
731 /* This is related to Duff's device (see
732 * http://en.wikipedia.org/wiki/Duff's_device). */
734 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
735 case CLS_F_IDX_##NAME: \
736 if (!field_matches(&a->flow, &b->flow, \
737 wildcards, nw_src_mask, nw_dst_mask, \
738 WILDCARDS, offsetof(struct flow, MEMBER), \
739 sizeof a->flow.MEMBER)) { \
749 /* Returns true if 'fixed' and 'wild' match. All fields in 'fixed' must have
750 * fixed values; 'wild' may contain wildcards.
752 * 'field_idx' is the index of the first field to be compared; fields before
753 * 'field_idx' are assumed to match. Always returns true if 'field_idx' is
756 rules_match_1wild(const struct cls_rule *fixed, const struct cls_rule *wild,
759 return rules_match(fixed, wild, wild->wc.wildcards, wild->wc.nw_src_mask,
760 wild->wc.nw_dst_mask, field_idx);
763 /* Returns true if 'wild1' and 'wild2' match, that is, if their fields
764 * are equal modulo wildcards in 'wild1' or 'wild2'.
766 * 'field_idx' is the index of the first field to be compared; fields before
767 * 'field_idx' are assumed to match. Always returns true if 'field_idx' is
770 rules_match_2wild(const struct cls_rule *wild1, const struct cls_rule *wild2,
773 return rules_match(wild1, wild2,
774 wild1->wc.wildcards | wild2->wc.wildcards,
775 wild1->wc.nw_src_mask & wild2->wc.nw_src_mask,
776 wild1->wc.nw_dst_mask & wild2->wc.nw_dst_mask,
780 /* Searches 'bucket' for a rule that matches 'target'. Returns the
781 * highest-priority match, if one is found, or a null pointer if there is no
784 * 'field_idx' must be the index of the first wildcarded field in 'bucket'. */
785 static struct cls_rule *
786 search_bucket(struct cls_bucket *bucket, int field_idx,
787 const struct cls_rule *target)
789 struct cls_rule *pos;
791 if (!equal_fields(&bucket->fixed, &target->flow, field_idx)) {
795 LIST_FOR_EACH (pos, node.list, &bucket->rules) {
796 if (rules_match_1wild(target, pos, field_idx)) {
803 /* Searches 'table' for a rule that matches 'target'. Returns the
804 * highest-priority match, if one is found, or a null pointer if there is no
807 * 'field_idx' must be the index of the first wildcarded field in 'table'. */
808 static struct cls_rule *
809 search_table(const struct hmap *table, int field_idx,
810 const struct cls_rule *target)
812 struct cls_bucket *bucket;
814 switch (hmap_count(table)) {
815 /* In these special cases there's no need to hash. */
819 bucket = CONTAINER_OF(hmap_first(table), struct cls_bucket, hmap_node);
820 return search_bucket(bucket, field_idx, target);
823 HMAP_FOR_EACH_WITH_HASH (bucket, hmap_node,
824 hash_fields(&target->flow, field_idx), table) {
825 struct cls_rule *rule = search_bucket(bucket, field_idx, target);
833 static struct cls_rule *
834 search_exact_table(const struct classifier *cls, size_t hash,
835 const struct flow *target)
837 struct cls_rule *rule;
839 HMAP_FOR_EACH_WITH_HASH (rule, node.hmap, hash, &cls->exact_table) {
840 if (flow_equal(&rule->flow, target)) {