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'. */
57 cls_rule_from_flow(const flow_t *flow, struct cls_rule *rule)
60 if (!rule->flow.wildcards && rule->flow.priority < UINT16_MAX) {
61 rule->flow.priority = UINT16_MAX;
63 flow_wildcards_init(&rule->wc, flow->wildcards);
64 rule->table_idx = table_idx_from_wildcards(flow->wildcards);
67 /* Converts the ofp_match in 'match' into a cls_rule in 'rule', with the given
68 * 'priority'. If 'tun_id_from_cookie' is set then the upper 32 bits of
69 * 'cookie' are stored in the rule as the tunnel ID. */
71 cls_rule_from_match(const struct ofp_match *match, unsigned int priority,
72 bool tun_id_from_cookie, uint64_t cookie,
73 struct cls_rule *rule)
75 flow_from_match(match, rule->flow.wildcards ? priority : UINT16_MAX,
76 tun_id_from_cookie, cookie, &rule->flow);
77 flow_wildcards_init(&rule->wc, rule->flow.wildcards);
78 rule->table_idx = table_idx_from_wildcards(rule->flow.wildcards);
81 /* Converts 'rule' to a string and returns the string. The caller must free
82 * the string (with free()). */
84 cls_rule_to_string(const struct cls_rule *rule)
86 struct ds s = DS_EMPTY_INITIALIZER;
87 ds_put_format(&s, "wildcards=%x priority=%u ",
88 rule->flow.wildcards, rule->flow.priority);
89 flow_format(&s, &rule->flow);
93 /* Prints cls_rule 'rule', for debugging.
95 * (The output could be improved and expanded, but this was good enough to
96 * debug the classifier.) */
98 cls_rule_print(const struct cls_rule *rule)
100 printf("wildcards=%x priority=%u ",
101 rule->flow.wildcards, rule->flow.priority);
102 flow_print(stdout, &rule->flow);
106 /* Adjusts pointers around 'old', which must be in classifier 'cls', to
107 * compensate for it having been moved in memory to 'new' (e.g. due to
110 * This function cannot be realized in all possible flow classifier
111 * implementations, so we will probably have to change the interface if we
112 * change the implementation. Shouldn't be a big deal though. */
114 cls_rule_moved(struct classifier *cls, struct cls_rule *old,
115 struct cls_rule *new)
118 if (new->flow.wildcards) {
119 list_moved(&new->node.list);
121 hmap_node_moved(&cls->exact_table,
122 &old->node.hmap, &new->node.hmap);
127 /* Replaces 'old', which must be in classifier 'cls', by 'new' (e.g. due to
128 * realloc()); that is, after calling this function 'new' will be in 'cls' in
131 * 'new' and 'old' must be exactly the same: wildcard the same fields, have the
132 * same fixed values for non-wildcarded fields, and have the same priority.
134 * The caller takes ownership of 'old' and is thus responsible for freeing it,
135 * etc., as necessary.
137 * This function cannot be realized in all possible flow classifier
138 * implementations, so we will probably have to change the interface if we
139 * change the implementation. Shouldn't be a big deal though. */
141 cls_rule_replace(struct classifier *cls, const struct cls_rule *old,
142 struct cls_rule *new)
145 assert(old->flow.wildcards == new->flow.wildcards);
146 assert(old->flow.priority == new->flow.priority);
148 if (new->flow.wildcards) {
149 list_replace(&new->node.list, &old->node.list);
151 hmap_replace(&cls->exact_table, &old->node.hmap, &new->node.hmap);
155 /* Initializes 'cls' as a classifier that initially contains no classification
158 classifier_init(struct classifier *cls)
163 for (i = 0; i < ARRAY_SIZE(cls->tables); i++) {
164 hmap_init(&cls->tables[i]);
166 hmap_init(&cls->exact_table);
169 /* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
170 * caller's responsibility. */
172 classifier_destroy(struct classifier *cls)
175 struct cls_bucket *bucket, *next_bucket;
178 for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
179 HMAP_FOR_EACH_SAFE (bucket, next_bucket, hmap_node, tbl) {
184 hmap_destroy(&cls->exact_table);
188 /* Returns true if 'cls' does not contain any classification rules, false
191 classifier_is_empty(const struct classifier *cls)
193 return cls->n_rules == 0;
196 /* Returns the number of rules in 'classifier'. */
198 classifier_count(const struct classifier *cls)
203 /* Returns the number of rules in 'classifier' that have no wildcards. */
205 classifier_count_exact(const struct classifier *cls)
207 return hmap_count(&cls->exact_table);
210 /* Returns the number of rules in 'classifier' that have at least one
213 classifier_count_wild(const struct classifier *cls)
215 return classifier_count(cls) - classifier_count_exact(cls);
218 /* Inserts 'rule' into 'cls'. Transfers ownership of 'rule' to 'cls'.
220 * If 'cls' already contains an identical rule (including wildcards, values of
221 * fixed fields, and priority), replaces the old rule by 'rule' and returns the
222 * rule that was replaced. The caller takes ownership of the returned rule and
223 * is thus responsible for freeing it, etc., as necessary.
225 * Returns NULL if 'cls' does not contain a rule with an identical key, after
226 * inserting the new rule. In this case, no rules are displaced by the new
227 * rule, even rules that cannot have any effect because the new rule matches a
228 * superset of their flows and has higher priority. */
230 classifier_insert(struct classifier *cls, struct cls_rule *rule)
232 struct cls_rule *old;
233 assert((rule->flow.wildcards == 0) == (rule->table_idx == CLS_F_IDX_EXACT));
234 old = (rule->flow.wildcards
235 ? table_insert(&cls->tables[rule->table_idx], rule)
236 : insert_exact_rule(cls, rule));
243 /* Inserts 'rule' into 'cls'. Transfers ownership of 'rule' to 'cls'.
245 * 'rule' must be an exact-match rule (rule->flow.wildcards must be 0) and 'cls'
246 * must not contain any rule with an identical key. */
248 classifier_insert_exact(struct classifier *cls, struct cls_rule *rule)
250 hmap_insert(&cls->exact_table, &rule->node.hmap,
251 flow_hash_headers(&rule->flow, 0));
255 /* Removes 'rule' from 'cls'. It is caller's responsibility to free 'rule', if
256 * this is desirable. */
258 classifier_remove(struct classifier *cls, struct cls_rule *rule)
260 if (rule->flow.wildcards) {
261 /* Remove 'rule' from bucket. If that empties the bucket, remove the
262 * bucket from its table. */
263 struct hmap *table = &cls->tables[rule->table_idx];
264 struct list *rules = list_remove(&rule->node.list);
265 if (list_is_empty(rules)) {
266 /* This code is a little tricky. list_remove() returns the list
267 * element just after the one removed. Since the list is now
268 * empty, this will be the address of the 'rules' member of the
269 * bucket that was just emptied, so pointer arithmetic (via
270 * CONTAINER_OF) can find that bucket. */
271 struct cls_bucket *bucket;
272 bucket = CONTAINER_OF(rules, struct cls_bucket, rules);
273 hmap_remove(table, &bucket->hmap_node);
277 /* Remove 'rule' from cls->exact_table. */
278 hmap_remove(&cls->exact_table, &rule->node.hmap);
283 /* Finds and returns the highest-priority rule in 'cls' that matches 'flow'.
284 * Returns a null pointer if no rules in 'cls' match 'flow'. If multiple rules
285 * of equal priority match 'flow', returns one arbitrarily.
287 * (When multiple rules of equal priority happen to fall into the same bucket,
288 * rules added more recently take priority over rules added less recently, but
289 * this is subject to change and should not be depended upon.) */
291 classifier_lookup(const struct classifier *cls, const flow_t *flow)
293 struct cls_rule *rule = classifier_lookup_exact(cls, flow);
295 rule = classifier_lookup_wild(cls, flow);
301 classifier_lookup_exact(const struct classifier *cls, const flow_t *flow)
303 return (!hmap_is_empty(&cls->exact_table)
304 ? search_exact_table(cls, flow_hash_headers(flow, 0), flow)
309 classifier_lookup_wild(const struct classifier *cls, const flow_t *flow)
311 struct cls_rule *best = NULL;
312 if (cls->n_rules > hmap_count(&cls->exact_table)) {
313 struct cls_rule target;
316 cls_rule_from_flow(flow, &target);
317 for (i = 0; i < CLS_N_FIELDS; i++) {
318 struct cls_rule *rule = search_table(&cls->tables[i], i, &target);
319 if (rule && (!best || rule->flow.priority > best->flow.priority)) {
328 classifier_find_rule_exactly(const struct classifier *cls,
329 const flow_t *target)
331 struct cls_bucket *bucket;
335 if (!target->wildcards) {
336 /* Ignores 'priority'. */
337 return search_exact_table(cls, flow_hash_headers(target, 0), target);
340 assert(target->wildcards == (target->wildcards & OVSFW_ALL));
341 table_idx = table_idx_from_wildcards(target->wildcards);
342 hash = hash_fields(target, table_idx);
343 HMAP_FOR_EACH_WITH_HASH (bucket, hmap_node, hash,
344 &cls->tables[table_idx]) {
345 if (equal_fields(&bucket->fixed, target, table_idx)) {
346 struct cls_rule *pos;
347 LIST_FOR_EACH (pos, node.list, &bucket->rules) {
348 if (pos->flow.priority < target->priority) {
350 } else if (pos->flow.priority == target->priority &&
351 pos->flow.wildcards == target->wildcards &&
352 flow_equal_headers(target, &pos->flow)) {
361 /* Checks if the flow defined by 'target' overlaps with any other rule at the
362 * same priority in the classifier. Two rules are considered overlapping if a
363 * packet could match both. */
365 classifier_rule_overlaps(const struct classifier *cls, const flow_t *target)
367 struct cls_rule target_rule;
368 const struct hmap *tbl;
370 if (!target->wildcards) {
371 return search_exact_table(cls, flow_hash_headers(target, 0), target) ?
375 cls_rule_from_flow(target, &target_rule);
377 for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
378 struct cls_bucket *bucket;
380 HMAP_FOR_EACH (bucket, hmap_node, tbl) {
381 struct cls_rule *rule;
383 LIST_FOR_EACH (rule, node.list, &bucket->rules) {
384 if (rule->flow.priority == target->priority
385 && rules_match_2wild(rule, &target_rule, 0)) {
395 /* Ignores target->flow.priority.
397 * 'callback' is allowed to delete the rule that is passed as its argument, but
398 * it must not delete (or move) any other rules in 'cls' that are in the same
399 * table as the argument rule. Two rules are in the same table if their
400 * cls_rule structs have the same table_idx; as a special case, a rule with
401 * wildcards and an exact-match rule will never be in the same table.
403 * If 'callback' returns nonzero then the iteration stops immediately and
404 * classifier_for_each_match() passes up the return value. Otherwise,
405 * classifier_for_each_match() returns 0 after completing the iteration. */
407 classifier_for_each_match(const struct classifier *cls,
408 const flow_t *target_flow,
409 int include, cls_cb_func *callback, void *aux)
411 struct cls_rule target;
413 cls_rule_from_flow(target_flow, &target);
414 if (include & CLS_INC_WILD) {
415 const struct hmap *table;
417 for (table = &cls->tables[0]; table < &cls->tables[CLS_N_FIELDS];
419 struct cls_bucket *bucket, *next_bucket;
421 HMAP_FOR_EACH_SAFE (bucket, next_bucket, hmap_node, table) {
422 /* XXX there is a bit of room for optimization here based on
423 * rejecting entire buckets on their fixed fields, but it will
424 * only be worthwhile for big buckets (which we hope we won't
425 * get anyway, but...) */
426 struct cls_rule *prev_rule, *rule;
428 /* We can't just use LIST_FOR_EACH_SAFE here because, if the
429 * callback deletes the last rule in the bucket, then the
430 * bucket itself will be destroyed. The bucket contains the
431 * list head so that's a use-after-free error. */
433 LIST_FOR_EACH (rule, node.list, &bucket->rules) {
434 if (rules_match_1wild(rule, &target, 0)) {
436 int retval = callback(prev_rule, aux);
445 int retval = callback(prev_rule, aux);
454 if (include & CLS_INC_EXACT) {
455 if (target.flow.wildcards) {
456 struct cls_rule *rule, *next_rule;
458 HMAP_FOR_EACH_SAFE (rule, next_rule, node.hmap,
460 if (rules_match_1wild(rule, &target, 0)) {
461 int retval = callback(rule, aux);
468 /* Optimization: there can be at most one match in the exact
470 size_t hash = flow_hash_headers(&target.flow, 0);
471 struct cls_rule *rule = search_exact_table(cls, hash,
474 int retval = callback(rule, aux);
485 /* 'callback' is allowed to delete the rule that is passed as its argument, but
486 * it must not delete (or move) any other rules in 'cls' that are in the same
487 * table as the argument rule. Two rules are in the same table if their
488 * cls_rule structs have the same table_idx; as a special case, a rule with
489 * wildcards and an exact-match rule will never be in the same table.
491 * If 'callback' returns nonzero then the iteration stops immediately and
492 * classifier_for_each() passes up the return value. Otherwise,
493 * classifier_for_each() returns 0 after completing the iteration. */
495 classifier_for_each(const struct classifier *cls, int include,
496 int (*callback)(struct cls_rule *, void *aux),
499 if (include & CLS_INC_WILD) {
500 const struct hmap *tbl;
502 for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
503 struct cls_bucket *bucket, *next_bucket;
505 HMAP_FOR_EACH_SAFE (bucket, next_bucket, hmap_node, tbl) {
506 struct cls_rule *prev_rule, *rule;
508 /* We can't just use LIST_FOR_EACH_SAFE here because, if the
509 * callback deletes the last rule in the bucket, then the
510 * bucket itself will be destroyed. The bucket contains the
511 * list head so that's a use-after-free error. */
513 LIST_FOR_EACH (rule, node.list, &bucket->rules) {
515 int retval = callback(prev_rule, aux);
523 int retval = callback(prev_rule, aux);
532 if (include & CLS_INC_EXACT) {
533 struct cls_rule *rule, *next_rule;
535 HMAP_FOR_EACH_SAFE (rule, next_rule, node.hmap, &cls->exact_table) {
536 int retval = callback(rule, aux);
546 static struct cls_bucket *create_bucket(struct hmap *, size_t hash,
547 const flow_t *fixed);
548 static struct cls_rule *bucket_insert(struct cls_bucket *, struct cls_rule *);
550 static inline bool equal_bytes(const void *, const void *, size_t n);
552 /* Returns a hash computed across the fields in 'flow' whose field indexes
553 * (CLS_F_IDX_*) are less than 'table_idx'. (If 'table_idx' is
554 * CLS_F_IDX_EXACT, hashes all the fields in 'flow'). */
556 hash_fields(const flow_t *flow, int table_idx)
558 /* I just know I'm going to hell for writing code this way.
560 * GCC generates pretty good code here, with only a single taken
561 * conditional jump per execution. Now the question is, would we be better
562 * off marking this function ALWAYS_INLINE and writing a wrapper that
563 * switches on the value of 'table_idx' to get rid of all the conditional
564 * jumps entirely (except for one in the wrapper)? Honestly I really,
565 * really hope that it doesn't matter in practice.
567 * We could do better by calculating hashes incrementally, instead of
568 * starting over from the top each time. But that would be even uglier. */
573 a = b = c = 0xdeadbeef + table_idx;
576 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
577 if (table_idx == CLS_F_IDX_##NAME) { \
579 memset((uint8_t *) tmp + n, 0, sizeof tmp - n); \
582 const size_t size = sizeof flow->MEMBER; \
583 const uint8_t *p1 = (const uint8_t *) &flow->MEMBER; \
584 const size_t p1_size = MIN(sizeof tmp - n, size); \
585 const uint8_t *p2 = p1 + p1_size; \
586 const size_t p2_size = size - p1_size; \
588 /* Append to 'tmp' as much data as will fit. */ \
589 memcpy((uint8_t *) tmp + n, p1, p1_size); \
592 /* If 'tmp' is full, mix. */ \
593 if (n == sizeof tmp) { \
601 /* Append to 'tmp' any data that didn't fit. */ \
602 memcpy(tmp, p2, p2_size); \
616 /* Compares the fields in 'a' and 'b' whose field indexes (CLS_F_IDX_*) are
617 * less than 'table_idx'. (If 'table_idx' is CLS_F_IDX_EXACT, compares all the
618 * fields in 'a' and 'b').
620 * Returns true if all the compared fields are equal, false otherwise. */
622 equal_fields(const flow_t *a, const flow_t *b, int table_idx)
624 /* XXX The generated code could be better here. */
625 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
626 if (table_idx == CLS_F_IDX_##NAME) { \
628 } else if (!equal_bytes(&a->MEMBER, &b->MEMBER, sizeof a->MEMBER)) { \
638 table_idx_from_wildcards(uint32_t wildcards)
641 return CLS_F_IDX_EXACT;
643 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
644 if (wildcards & WILDCARDS) { \
645 return CLS_F_IDX_##NAME; \
652 /* Inserts 'rule' into 'table'. Returns the rule, if any, that was displaced
653 * in favor of 'rule'. */
654 static struct cls_rule *
655 table_insert(struct hmap *table, struct cls_rule *rule)
657 struct cls_bucket *bucket;
660 hash = hash_fields(&rule->flow, rule->table_idx);
661 bucket = find_bucket(table, hash, rule);
663 bucket = create_bucket(table, hash, &rule->flow);
666 return bucket_insert(bucket, rule);
669 /* Inserts 'rule' into 'bucket', given that 'field' is the first wildcarded
672 * Returns the rule, if any, that was displaced in favor of 'rule'. */
673 static struct cls_rule *
674 bucket_insert(struct cls_bucket *bucket, struct cls_rule *rule)
676 struct cls_rule *pos;
677 LIST_FOR_EACH (pos, node.list, &bucket->rules) {
678 if (pos->flow.priority == rule->flow.priority) {
679 if (pos->flow.wildcards == rule->flow.wildcards
680 && rules_match_1wild(pos, rule, rule->table_idx))
682 list_replace(&rule->node.list, &pos->node.list);
685 } else if (pos->flow.priority < rule->flow.priority) {
689 list_insert(&pos->node.list, &rule->node.list);
693 static struct cls_rule *
694 insert_exact_rule(struct classifier *cls, struct cls_rule *rule)
696 struct cls_rule *old_rule;
699 hash = flow_hash_headers(&rule->flow, 0);
700 old_rule = search_exact_table(cls, hash, &rule->flow);
702 hmap_remove(&cls->exact_table, &old_rule->node.hmap);
704 hmap_insert(&cls->exact_table, &rule->node.hmap, hash);
708 /* Returns the bucket in 'table' that has the given 'hash' and the same fields
709 * as 'rule->flow' (up to 'rule->table_idx'), or a null pointer if no bucket
711 static struct cls_bucket *
712 find_bucket(struct hmap *table, size_t hash, const struct cls_rule *rule)
714 struct cls_bucket *bucket;
715 HMAP_FOR_EACH_WITH_HASH (bucket, hmap_node, hash, table) {
716 if (equal_fields(&bucket->fixed, &rule->flow, rule->table_idx)) {
723 /* Creates a bucket and inserts it in 'table' with the given 'hash' and 'fixed'
724 * values. Returns the new bucket. */
725 static struct cls_bucket *
726 create_bucket(struct hmap *table, size_t hash, const flow_t *fixed)
728 struct cls_bucket *bucket = xmalloc(sizeof *bucket);
729 list_init(&bucket->rules);
730 bucket->fixed = *fixed;
731 hmap_insert(table, &bucket->hmap_node, hash);
735 /* Returns true if the 'n' bytes in 'a' and 'b' are equal, false otherwise. */
736 static inline bool ALWAYS_INLINE
737 equal_bytes(const void *a, const void *b, size_t n)
740 /* For some reason GCC generates stupid code for memcmp() of small
741 * constant integer lengths. Help it out.
743 * This function is always inlined, and it is always called with 'n' as a
744 * compile-time constant, so the switch statement gets optimized out and
745 * this whole function just expands to an instruction or two. */
748 return *(uint8_t *) a == *(uint8_t *) b;
751 return *(uint16_t *) a == *(uint16_t *) b;
754 return *(uint32_t *) a == *(uint32_t *) b;
757 return (*(uint32_t *) a == *(uint32_t *) b
758 && ((uint16_t *) a)[2] == ((uint16_t *) b)[2]);
764 /* I hope GCC is smarter on your platform. */
765 return !memcmp(a, b, n);
769 /* Returns the 32-bit unsigned integer at 'p'. */
770 static inline uint32_t
771 read_uint32(const void *p)
773 /* GCC optimizes this into a single machine instruction on x86. */
775 memcpy(&x, p, sizeof x);
779 /* Compares the specified field in 'a' and 'b'. Returns true if the fields are
780 * equal, or if the ofp_match wildcard bits in 'wildcards' are set such that
781 * non-equal values may be ignored. 'nw_src_mask' and 'nw_dst_mask' must be
782 * those that would be set for 'wildcards' by cls_rule_set_masks().
784 * The compared field is the one with wildcard bit or bits 'field_wc', offset
785 * 'rule_ofs' within cls_rule's "fields" member, and length 'len', in bytes. */
786 static inline bool ALWAYS_INLINE
787 field_matches(const flow_t *a_, const flow_t *b_,
788 uint32_t wildcards, uint32_t nw_src_mask, uint32_t nw_dst_mask,
789 uint32_t field_wc, int ofs, int len)
791 /* This function is always inlined, and it is always called with 'field_wc'
792 * as a compile-time constant, so the "if" conditionals here generate no
794 const void *a = (const uint8_t *) a_ + ofs;
795 const void *b = (const uint8_t *) b_ + ofs;
796 if (!(field_wc & (field_wc - 1))) {
797 /* Handle all the single-bit wildcard cases. */
798 return wildcards & field_wc || equal_bytes(a, b, len);
799 } else if (field_wc == OFPFW_NW_SRC_MASK ||
800 field_wc == OFPFW_NW_DST_MASK) {
801 uint32_t a_ip = read_uint32(a);
802 uint32_t b_ip = read_uint32(b);
803 uint32_t mask = (field_wc == OFPFW_NW_SRC_MASK
804 ? nw_src_mask : nw_dst_mask);
805 return ((a_ip ^ b_ip) & mask) == 0;
811 /* Returns true if 'a' and 'b' match, ignoring fields for which the wildcards
812 * in 'wildcards' are set. 'nw_src_mask' and 'nw_dst_mask' must be those that
813 * would be set for 'wildcards' by cls_rule_set_masks(). 'field_idx' is the
814 * index of the first field to be compared; fields before 'field_idx' are
815 * assumed to match. (Always returns true if 'field_idx' is CLS_N_FIELDS.) */
817 rules_match(const struct cls_rule *a, const struct cls_rule *b,
818 uint32_t wildcards, uint32_t nw_src_mask, uint32_t nw_dst_mask,
821 /* This is related to Duff's device (see
822 * http://en.wikipedia.org/wiki/Duff's_device). */
824 #define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
825 case CLS_F_IDX_##NAME: \
826 if (!field_matches(&a->flow, &b->flow, \
827 wildcards, nw_src_mask, nw_dst_mask, \
828 WILDCARDS, offsetof(flow_t, MEMBER), \
829 sizeof a->flow.MEMBER)) { \
839 /* Returns true if 'fixed' and 'wild' match. All fields in 'fixed' must have
840 * fixed values; 'wild' may contain wildcards.
842 * 'field_idx' is the index of the first field to be compared; fields before
843 * 'field_idx' are assumed to match. Always returns true if 'field_idx' is
846 rules_match_1wild(const struct cls_rule *fixed, const struct cls_rule *wild,
849 return rules_match(fixed, wild, wild->flow.wildcards, wild->wc.nw_src_mask,
850 wild->wc.nw_dst_mask, field_idx);
853 /* Returns true if 'wild1' and 'wild2' match, that is, if their fields
854 * are equal modulo wildcards in 'wild1' or 'wild2'.
856 * 'field_idx' is the index of the first field to be compared; fields before
857 * 'field_idx' are assumed to match. Always returns true if 'field_idx' is
860 rules_match_2wild(const struct cls_rule *wild1, const struct cls_rule *wild2,
863 return rules_match(wild1, wild2,
864 wild1->flow.wildcards | wild2->flow.wildcards,
865 wild1->wc.nw_src_mask & wild2->wc.nw_src_mask,
866 wild1->wc.nw_dst_mask & wild2->wc.nw_dst_mask,
870 /* Searches 'bucket' for a rule that matches 'target'. Returns the
871 * highest-priority match, if one is found, or a null pointer if there is no
874 * 'field_idx' must be the index of the first wildcarded field in 'bucket'. */
875 static struct cls_rule *
876 search_bucket(struct cls_bucket *bucket, int field_idx,
877 const struct cls_rule *target)
879 struct cls_rule *pos;
881 if (!equal_fields(&bucket->fixed, &target->flow, field_idx)) {
885 LIST_FOR_EACH (pos, node.list, &bucket->rules) {
886 if (rules_match_1wild(target, pos, field_idx)) {
893 /* Searches 'table' for a rule that matches 'target'. Returns the
894 * highest-priority match, if one is found, or a null pointer if there is no
897 * 'field_idx' must be the index of the first wildcarded field in 'table'. */
898 static struct cls_rule *
899 search_table(const struct hmap *table, int field_idx,
900 const struct cls_rule *target)
902 struct cls_bucket *bucket;
904 switch (hmap_count(table)) {
905 /* In these special cases there's no need to hash. */
909 bucket = CONTAINER_OF(hmap_first(table), struct cls_bucket, hmap_node);
910 return search_bucket(bucket, field_idx, target);
913 HMAP_FOR_EACH_WITH_HASH (bucket, hmap_node,
914 hash_fields(&target->flow, field_idx), table) {
915 struct cls_rule *rule = search_bucket(bucket, field_idx, target);
923 static struct cls_rule *
924 search_exact_table(const struct classifier *cls, size_t hash,
925 const flow_t *target)
927 struct cls_rule *rule;
929 HMAP_FOR_EACH_WITH_HASH (rule, node.hmap, hash, &cls->exact_table) {
930 if (flow_equal_headers(&rule->flow, target)) {