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(flow_t, MEMBER), \
29 sizeof ((flow_t *)0)->MEMBER, \
34 { sizeof(flow_t), 0, 0, "exact" },
37 static uint32_t hash_fields(const flow_t *, int table_idx);
38 static bool equal_fields(const flow_t *, const flow_t *, int table_idx);
40 static int table_idx_from_wildcards(uint32_t wildcards);
41 static struct cls_rule *table_insert(struct hmap *, struct cls_rule *);
42 static struct cls_rule *insert_exact_rule(struct classifier *,
44 static struct cls_bucket *find_bucket(struct hmap *, size_t hash,
45 const struct cls_rule *);
46 static struct cls_rule *search_table(const struct hmap *table, int field_idx,
47 const struct cls_rule *);
48 static struct cls_rule *search_exact_table(const struct classifier *,
49 size_t hash, const flow_t *);
50 static bool rules_match_1wild(const struct cls_rule *fixed,
51 const struct cls_rule *wild, int field_idx);
52 static bool rules_match_2wild(const struct cls_rule *wild1,
53 const struct cls_rule *wild2, int field_idx);
55 /* Converts the flow in 'flow' into a cls_rule in 'rule', with the given
56 * 'wildcards' and 'priority'.*/
58 cls_rule_from_flow(const flow_t *flow, uint32_t wildcards,
59 unsigned int priority, struct cls_rule *rule)
61 assert(!flow->reserved[0] && !flow->reserved[1] && !flow->reserved[2]);
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 /* Adjusts pointers around 'old', which must be in classifier 'cls', to
108 * compensate for it having been moved in memory to 'new' (e.g. due to
111 * This function cannot be realized in all possible flow classifier
112 * implementations, so we will probably have to change the interface if we
113 * change the implementation. Shouldn't be a big deal though. */
115 cls_rule_moved(struct classifier *cls, struct cls_rule *old,
116 struct cls_rule *new)
119 if (new->wc.wildcards) {
120 list_moved(&new->node.list);
122 hmap_node_moved(&cls->exact_table,
123 &old->node.hmap, &new->node.hmap);
128 /* Replaces 'old', which must be in classifier 'cls', by 'new' (e.g. due to
129 * realloc()); that is, after calling this function 'new' will be in 'cls' in
132 * 'new' and 'old' must be exactly the same: wildcard the same fields, have the
133 * same fixed values for non-wildcarded fields, and have the same priority.
135 * The caller takes ownership of 'old' and is thus responsible for freeing it,
136 * etc., as necessary.
138 * This function cannot be realized in all possible flow classifier
139 * implementations, so we will probably have to change the interface if we
140 * change the implementation. Shouldn't be a big deal though. */
142 cls_rule_replace(struct classifier *cls, const struct cls_rule *old,
143 struct cls_rule *new)
146 assert(old->wc.wildcards == new->wc.wildcards);
147 assert(old->priority == new->priority);
149 if (new->wc.wildcards) {
150 list_replace(&new->node.list, &old->node.list);
152 hmap_replace(&cls->exact_table, &old->node.hmap, &new->node.hmap);
156 /* Initializes 'cls' as a classifier that initially contains no classification
159 classifier_init(struct classifier *cls)
164 for (i = 0; i < ARRAY_SIZE(cls->tables); i++) {
165 hmap_init(&cls->tables[i]);
167 hmap_init(&cls->exact_table);
170 /* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
171 * caller's responsibility. */
173 classifier_destroy(struct classifier *cls)
176 struct cls_bucket *bucket, *next_bucket;
179 for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
180 HMAP_FOR_EACH_SAFE (bucket, next_bucket,
181 struct cls_bucket, hmap_node, tbl) {
186 hmap_destroy(&cls->exact_table);
190 /* Returns true if 'cls' does not contain any classification rules, false
193 classifier_is_empty(const struct classifier *cls)
195 return cls->n_rules == 0;
198 /* Returns the number of rules in 'classifier'. */
200 classifier_count(const struct classifier *cls)
205 /* Returns the number of rules in 'classifier' that have no wildcards. */
207 classifier_count_exact(const struct classifier *cls)
209 return hmap_count(&cls->exact_table);
212 /* Inserts 'rule' into 'cls'. Transfers ownership of 'rule' to 'cls'.
214 * If 'cls' already contains an identical rule (including wildcards, values of
215 * fixed fields, and priority), replaces the old rule by 'rule' and returns the
216 * rule that was replaced. The caller takes ownership of the returned rule and
217 * is thus responsible for freeing it, etc., as necessary.
219 * Returns NULL if 'cls' does not contain a rule with an identical key, after
220 * inserting the new rule. In this case, no rules are displaced by the new
221 * rule, even rules that cannot have any effect because the new rule matches a
222 * superset of their flows and has higher priority. */
224 classifier_insert(struct classifier *cls, struct cls_rule *rule)
226 struct cls_rule *old;
227 assert((rule->wc.wildcards == 0) == (rule->table_idx == CLS_F_IDX_EXACT));
228 old = (rule->wc.wildcards
229 ? table_insert(&cls->tables[rule->table_idx], rule)
230 : insert_exact_rule(cls, rule));
237 /* Inserts 'rule' into 'cls'. Transfers ownership of 'rule' to 'cls'.
239 * 'rule' must be an exact-match rule (rule->wc.wildcards must be 0) and 'cls'
240 * must not contain any rule with an identical key. */
242 classifier_insert_exact(struct classifier *cls, struct cls_rule *rule)
244 hmap_insert(&cls->exact_table, &rule->node.hmap,
245 flow_hash(&rule->flow, 0));
249 /* Removes 'rule' from 'cls'. It is caller's responsibility to free 'rule', if
250 * this is desirable. */
252 classifier_remove(struct classifier *cls, struct cls_rule *rule)
254 if (rule->wc.wildcards) {
255 /* Remove 'rule' from bucket. If that empties the bucket, remove the
256 * bucket from its table. */
257 struct hmap *table = &cls->tables[rule->table_idx];
258 struct list *rules = list_remove(&rule->node.list);
259 if (list_is_empty(rules)) {
260 /* This code is a little tricky. list_remove() returns the list
261 * element just after the one removed. Since the list is now
262 * empty, this will be the address of the 'rules' member of the
263 * bucket that was just emptied, so pointer arithmetic (via
264 * CONTAINER_OF) can find that bucket. */
265 struct cls_bucket *bucket;
266 bucket = CONTAINER_OF(rules, struct cls_bucket, rules);
267 hmap_remove(table, &bucket->hmap_node);
271 /* Remove 'rule' from cls->exact_table. */
272 hmap_remove(&cls->exact_table, &rule->node.hmap);
277 /* Finds and returns the highest-priority rule in 'cls' that matches 'flow'.
278 * Returns a null pointer if no rules in 'cls' match 'flow'. If multiple rules
279 * of equal priority match 'flow', returns one arbitrarily.
281 * (When multiple rules of equal priority happen to fall into the same bucket,
282 * rules added more recently take priority over rules added less recently, but
283 * this is subject to change and should not be depended upon.) */
285 classifier_lookup(const struct classifier *cls, const flow_t *flow)
287 struct cls_rule *rule = classifier_lookup_exact(cls, flow);
289 rule = classifier_lookup_wild(cls, flow);
295 classifier_lookup_exact(const struct classifier *cls, const flow_t *flow)
297 return (!hmap_is_empty(&cls->exact_table)
298 ? search_exact_table(cls, flow_hash(flow, 0), flow)
303 classifier_lookup_wild(const struct classifier *cls, const flow_t *flow)
305 struct cls_rule *best = NULL;
306 if (cls->n_rules > hmap_count(&cls->exact_table)) {
307 struct cls_rule target;
310 cls_rule_from_flow(flow, 0, 0, &target);
311 for (i = 0; i < CLS_N_FIELDS; i++) {
312 struct cls_rule *rule = search_table(&cls->tables[i], i, &target);
313 if (rule && (!best || rule->priority > best->priority)) {
322 classifier_find_rule_exactly(const struct classifier *cls,
323 const flow_t *target, uint32_t wildcards,
324 unsigned int priority)
326 struct cls_bucket *bucket;
331 /* Ignores 'priority'. */
332 return search_exact_table(cls, flow_hash(target, 0), target);
335 assert(wildcards == (wildcards & OVSFW_ALL));
336 table_idx = table_idx_from_wildcards(wildcards);
337 hash = hash_fields(target, table_idx);
338 HMAP_FOR_EACH_WITH_HASH (bucket, struct cls_bucket, hmap_node, hash,
339 &cls->tables[table_idx]) {
340 if (equal_fields(&bucket->fixed, target, table_idx)) {
341 struct cls_rule *pos;
342 LIST_FOR_EACH (pos, struct cls_rule, node.list, &bucket->rules) {
343 if (pos->priority < priority) {
345 } else if (pos->priority == priority &&
346 pos->wc.wildcards == wildcards &&
347 flow_equal(target, &pos->flow)) {
356 /* Checks if the flow defined by 'target' with 'wildcards' at 'priority'
357 * overlaps with any other rule at the same priority in the classifier.
358 * Two rules are considered overlapping if a packet could match both. */
360 classifier_rule_overlaps(const struct classifier *cls,
361 const flow_t *target, uint32_t wildcards,
362 unsigned int priority)
364 struct cls_rule target_rule;
365 const struct hmap *tbl;
368 return search_exact_table(cls, flow_hash(target, 0), target) ?
372 cls_rule_from_flow(target, wildcards, priority, &target_rule);
374 for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
375 struct cls_bucket *bucket;
377 HMAP_FOR_EACH (bucket, struct cls_bucket, hmap_node, tbl) {
378 struct cls_rule *rule;
380 LIST_FOR_EACH (rule, struct cls_rule, node.list,
382 if (rule->priority == priority
383 && rules_match_2wild(rule, &target_rule, 0)) {
393 /* Ignores target->priority.
395 * 'callback' is allowed to delete the rule that is passed as its argument, but
396 * it must not delete (or move) any other rules in 'cls' that are in the same
397 * table as the argument rule. Two rules are in the same table if their
398 * cls_rule structs have the same table_idx; as a special case, a rule with
399 * wildcards and an exact-match rule will never be in the same table. */
401 classifier_for_each_match(const struct classifier *cls,
402 const struct cls_rule *target,
403 int include, cls_cb_func *callback, void *aux)
405 if (include & CLS_INC_WILD) {
406 const struct hmap *table;
408 for (table = &cls->tables[0]; table < &cls->tables[CLS_N_FIELDS];
410 struct cls_bucket *bucket, *next_bucket;
412 HMAP_FOR_EACH_SAFE (bucket, next_bucket,
413 struct cls_bucket, hmap_node, table) {
414 /* XXX there is a bit of room for optimization here based on
415 * rejecting entire buckets on their fixed fields, but it will
416 * only be worthwhile for big buckets (which we hope we won't
417 * get anyway, but...) */
418 struct cls_rule *prev_rule, *rule;
420 /* We can't just use LIST_FOR_EACH_SAFE here because, if the
421 * callback deletes the last rule in the bucket, then the
422 * bucket itself will be destroyed. The bucket contains the
423 * list head so that's a use-after-free error. */
425 LIST_FOR_EACH (rule, struct cls_rule, node.list,
427 if (rules_match_1wild(rule, target, 0)) {
429 callback(prev_rule, aux);
435 callback(prev_rule, aux);
441 if (include & CLS_INC_EXACT) {
442 if (target->wc.wildcards) {
443 struct cls_rule *rule, *next_rule;
445 HMAP_FOR_EACH_SAFE (rule, next_rule, struct cls_rule, node.hmap,
447 if (rules_match_1wild(rule, target, 0)) {
452 /* Optimization: there can be at most one match in the exact
454 size_t hash = flow_hash(&target->flow, 0);
455 struct cls_rule *rule = search_exact_table(cls, hash,
464 /* 'callback' is allowed to delete the rule that is passed as its argument, but
465 * it must not delete (or move) any other rules in 'cls' that are in the same
466 * table as the argument rule. Two rules are in the same table if their
467 * cls_rule structs have the same table_idx; as a special case, a rule with
468 * wildcards and an exact-match rule will never be in the same table.
470 * If 'include' is CLS_INC_EXACT then CLASSIFIER_FOR_EACH_EXACT_RULE(_SAFE) is
471 * probably easier to use. */
473 classifier_for_each(const struct classifier *cls, int include,
474 void (*callback)(struct cls_rule *, void *aux),
477 if (include & CLS_INC_WILD) {
478 const struct hmap *tbl;
480 for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
481 struct cls_bucket *bucket, *next_bucket;
483 HMAP_FOR_EACH_SAFE (bucket, next_bucket,
484 struct cls_bucket, hmap_node, tbl) {
485 struct cls_rule *prev_rule, *rule;
487 /* We can't just use LIST_FOR_EACH_SAFE here because, if the
488 * callback deletes the last rule in the bucket, then the
489 * bucket itself will be destroyed. The bucket contains the
490 * list head so that's a use-after-free error. */
492 LIST_FOR_EACH (rule, struct cls_rule, node.list,
495 callback(prev_rule, aux);
500 callback(prev_rule, aux);
506 if (include & CLS_INC_EXACT) {
507 struct cls_rule *rule, *next_rule;
509 HMAP_FOR_EACH_SAFE (rule, next_rule,
510 struct cls_rule, node.hmap, &cls->exact_table) {
516 static struct cls_bucket *create_bucket(struct hmap *, size_t hash,
517 const flow_t *fixed);
518 static struct cls_rule *bucket_insert(struct cls_bucket *, struct cls_rule *);
520 static inline bool equal_bytes(const void *, const void *, size_t n);
522 /* Returns a hash computed across the fields in 'flow' whose field indexes
523 * (CLS_F_IDX_*) are less than 'table_idx'. (If 'table_idx' is
524 * CLS_F_IDX_EXACT, hashes all the fields in 'flow'). */
526 hash_fields(const flow_t *flow, int table_idx)
528 /* I just know I'm going to hell for writing code this way.
530 * GCC generates pretty good code here, with only a single taken
531 * conditional jump per execution. Now the question is, would we be better
532 * off marking this function ALWAYS_INLINE and writing a wrapper that
533 * switches on the value of 'table_idx' to get rid of all the conditional
534 * jumps entirely (except for one in the wrapper)? Honestly I really,
535 * really hope that it doesn't matter in practice.
537 * We could do better by calculating hashes incrementally, instead of
538 * starting over from the top each time. But that would be even uglier. */
543 a = b = c = 0xdeadbeef + table_idx;
546 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
547 if (table_idx == CLS_F_IDX_##NAME) { \
549 memset((uint8_t *) tmp + n, 0, sizeof tmp - n); \
552 const size_t size = sizeof flow->MEMBER; \
553 const uint8_t *p1 = (const uint8_t *) &flow->MEMBER; \
554 const size_t p1_size = MIN(sizeof tmp - n, size); \
555 const uint8_t *p2 = p1 + p1_size; \
556 const size_t p2_size = size - p1_size; \
558 /* Append to 'tmp' as much data as will fit. */ \
559 memcpy((uint8_t *) tmp + n, p1, p1_size); \
562 /* If 'tmp' is full, mix. */ \
563 if (n == sizeof tmp) { \
571 /* Append to 'tmp' any data that didn't fit. */ \
572 memcpy(tmp, p2, p2_size); \
586 /* Compares the fields in 'a' and 'b' whose field indexes (CLS_F_IDX_*) are
587 * less than 'table_idx'. (If 'table_idx' is CLS_F_IDX_EXACT, compares all the
588 * fields in 'a' and 'b').
590 * Returns true if all the compared fields are equal, false otherwise. */
592 equal_fields(const flow_t *a, const flow_t *b, int table_idx)
594 /* XXX The generated code could be better here. */
595 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
596 if (table_idx == CLS_F_IDX_##NAME) { \
598 } else if (!equal_bytes(&a->MEMBER, &b->MEMBER, sizeof a->MEMBER)) { \
608 table_idx_from_wildcards(uint32_t wildcards)
611 return CLS_F_IDX_EXACT;
613 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
614 if (wildcards & WILDCARDS) { \
615 return CLS_F_IDX_##NAME; \
622 /* Inserts 'rule' into 'table'. Returns the rule, if any, that was displaced
623 * in favor of 'rule'. */
624 static struct cls_rule *
625 table_insert(struct hmap *table, struct cls_rule *rule)
627 struct cls_bucket *bucket;
630 hash = hash_fields(&rule->flow, rule->table_idx);
631 bucket = find_bucket(table, hash, rule);
633 bucket = create_bucket(table, hash, &rule->flow);
636 return bucket_insert(bucket, rule);
639 /* Inserts 'rule' into 'bucket', given that 'field' is the first wildcarded
642 * Returns the rule, if any, that was displaced in favor of 'rule'. */
643 static struct cls_rule *
644 bucket_insert(struct cls_bucket *bucket, struct cls_rule *rule)
646 struct cls_rule *pos;
647 LIST_FOR_EACH (pos, struct cls_rule, node.list, &bucket->rules) {
648 if (pos->priority == rule->priority) {
649 if (pos->wc.wildcards == rule->wc.wildcards
650 && rules_match_1wild(pos, rule, rule->table_idx))
652 list_replace(&rule->node.list, &pos->node.list);
655 } else if (pos->priority < rule->priority) {
659 list_insert(&pos->node.list, &rule->node.list);
663 static struct cls_rule *
664 insert_exact_rule(struct classifier *cls, struct cls_rule *rule)
666 struct cls_rule *old_rule;
669 hash = flow_hash(&rule->flow, 0);
670 old_rule = search_exact_table(cls, hash, &rule->flow);
672 hmap_remove(&cls->exact_table, &old_rule->node.hmap);
674 hmap_insert(&cls->exact_table, &rule->node.hmap, hash);
678 /* Returns the bucket in 'table' that has the given 'hash' and the same fields
679 * as 'rule->flow' (up to 'rule->table_idx'), or a null pointer if no bucket
681 static struct cls_bucket *
682 find_bucket(struct hmap *table, size_t hash, const struct cls_rule *rule)
684 struct cls_bucket *bucket;
685 HMAP_FOR_EACH_WITH_HASH (bucket, struct cls_bucket, hmap_node, hash,
687 if (equal_fields(&bucket->fixed, &rule->flow, rule->table_idx)) {
694 /* Creates a bucket and inserts it in 'table' with the given 'hash' and 'fixed'
695 * values. Returns the new bucket. */
696 static struct cls_bucket *
697 create_bucket(struct hmap *table, size_t hash, const flow_t *fixed)
699 struct cls_bucket *bucket = xmalloc(sizeof *bucket);
700 list_init(&bucket->rules);
701 bucket->fixed = *fixed;
702 hmap_insert(table, &bucket->hmap_node, hash);
706 /* Returns true if the 'n' bytes in 'a' and 'b' are equal, false otherwise. */
707 static inline bool ALWAYS_INLINE
708 equal_bytes(const void *a, const void *b, size_t n)
711 /* For some reason GCC generates stupid code for memcmp() of small
712 * constant integer lengths. Help it out.
714 * This function is always inlined, and it is always called with 'n' as a
715 * compile-time constant, so the switch statement gets optimized out and
716 * this whole function just expands to an instruction or two. */
719 return *(uint8_t *) a == *(uint8_t *) b;
722 return *(uint16_t *) a == *(uint16_t *) b;
725 return *(uint32_t *) a == *(uint32_t *) b;
728 return (*(uint32_t *) a == *(uint32_t *) b
729 && ((uint16_t *) a)[2] == ((uint16_t *) b)[2]);
735 /* I hope GCC is smarter on your platform. */
736 return !memcmp(a, b, n);
740 /* Returns the 32-bit unsigned integer at 'p'. */
741 static inline uint32_t
742 read_uint32(const void *p)
744 /* GCC optimizes this into a single machine instruction on x86. */
746 memcpy(&x, p, sizeof x);
750 /* Compares the specified field in 'a' and 'b'. Returns true if the fields are
751 * equal, or if the ofp_match wildcard bits in 'wildcards' are set such that
752 * non-equal values may be ignored. 'nw_src_mask' and 'nw_dst_mask' must be
753 * those that would be set for 'wildcards' by cls_rule_set_masks().
755 * The compared field is the one with wildcard bit or bits 'field_wc', offset
756 * 'rule_ofs' within cls_rule's "fields" member, and length 'len', in bytes. */
757 static inline bool ALWAYS_INLINE
758 field_matches(const flow_t *a_, const flow_t *b_,
759 uint32_t wildcards, uint32_t nw_src_mask, uint32_t nw_dst_mask,
760 uint32_t field_wc, int ofs, int len)
762 /* This function is always inlined, and it is always called with 'field_wc'
763 * as a compile-time constant, so the "if" conditionals here generate no
765 const void *a = (const uint8_t *) a_ + ofs;
766 const void *b = (const uint8_t *) b_ + ofs;
767 if (!(field_wc & (field_wc - 1))) {
768 /* Handle all the single-bit wildcard cases. */
769 return wildcards & field_wc || equal_bytes(a, b, len);
770 } else if (field_wc == OFPFW_NW_SRC_MASK ||
771 field_wc == OFPFW_NW_DST_MASK) {
772 uint32_t a_ip = read_uint32(a);
773 uint32_t b_ip = read_uint32(b);
774 uint32_t mask = (field_wc == OFPFW_NW_SRC_MASK
775 ? nw_src_mask : nw_dst_mask);
776 return ((a_ip ^ b_ip) & mask) == 0;
782 /* Returns true if 'a' and 'b' match, ignoring fields for which the wildcards
783 * in 'wildcards' are set. 'nw_src_mask' and 'nw_dst_mask' must be those that
784 * would be set for 'wildcards' by cls_rule_set_masks(). 'field_idx' is the
785 * index of the first field to be compared; fields before 'field_idx' are
786 * assumed to match. (Always returns true if 'field_idx' is CLS_N_FIELDS.) */
788 rules_match(const struct cls_rule *a, const struct cls_rule *b,
789 uint32_t wildcards, uint32_t nw_src_mask, uint32_t nw_dst_mask,
792 /* This is related to Duff's device (see
793 * http://en.wikipedia.org/wiki/Duff's_device). */
795 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
796 case CLS_F_IDX_##NAME: \
797 if (!field_matches(&a->flow, &b->flow, \
798 wildcards, nw_src_mask, nw_dst_mask, \
799 WILDCARDS, offsetof(flow_t, MEMBER), \
800 sizeof a->flow.MEMBER)) { \
810 /* Returns true if 'fixed' and 'wild' match. All fields in 'fixed' must have
811 * fixed values; 'wild' may contain wildcards.
813 * 'field_idx' is the index of the first field to be compared; fields before
814 * 'field_idx' are assumed to match. Always returns true if 'field_idx' is
817 rules_match_1wild(const struct cls_rule *fixed, const struct cls_rule *wild,
820 return rules_match(fixed, wild, wild->wc.wildcards, wild->wc.nw_src_mask,
821 wild->wc.nw_dst_mask, field_idx);
824 /* Returns true if 'wild1' and 'wild2' match, that is, if their fields
825 * are equal modulo wildcards in 'wild1' or 'wild2'.
827 * 'field_idx' is the index of the first field to be compared; fields before
828 * 'field_idx' are assumed to match. Always returns true if 'field_idx' is
831 rules_match_2wild(const struct cls_rule *wild1, const struct cls_rule *wild2,
834 return rules_match(wild1, wild2,
835 wild1->wc.wildcards | wild2->wc.wildcards,
836 wild1->wc.nw_src_mask & wild2->wc.nw_src_mask,
837 wild1->wc.nw_dst_mask & wild2->wc.nw_dst_mask,
841 /* Searches 'bucket' for a rule that matches 'target'. Returns the
842 * highest-priority match, if one is found, or a null pointer if there is no
845 * 'field_idx' must be the index of the first wildcarded field in 'bucket'. */
846 static struct cls_rule *
847 search_bucket(struct cls_bucket *bucket, int field_idx,
848 const struct cls_rule *target)
850 struct cls_rule *pos;
852 if (!equal_fields(&bucket->fixed, &target->flow, field_idx)) {
856 LIST_FOR_EACH (pos, struct cls_rule, node.list, &bucket->rules) {
857 if (rules_match_1wild(target, pos, field_idx)) {
864 /* Searches 'table' for a rule that matches 'target'. Returns the
865 * highest-priority match, if one is found, or a null pointer if there is no
868 * 'field_idx' must be the index of the first wildcarded field in 'table'. */
869 static struct cls_rule *
870 search_table(const struct hmap *table, int field_idx,
871 const struct cls_rule *target)
873 struct cls_bucket *bucket;
875 switch (hmap_count(table)) {
876 /* In these special cases there's no need to hash. */
880 bucket = CONTAINER_OF(hmap_first(table), struct cls_bucket, hmap_node);
881 return search_bucket(bucket, field_idx, target);
884 HMAP_FOR_EACH_WITH_HASH (bucket, struct cls_bucket, hmap_node,
885 hash_fields(&target->flow, field_idx), table) {
886 struct cls_rule *rule = search_bucket(bucket, field_idx, target);
894 static struct cls_rule *
895 search_exact_table(const struct classifier *cls, size_t hash,
896 const flow_t *target)
898 struct cls_rule *rule;
900 HMAP_FOR_EACH_WITH_HASH (rule, struct cls_rule, node.hmap,
901 hash, &cls->exact_table) {
902 if (flow_equal(&rule->flow, target)) {