2 * Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include "classifier.h"
20 #include <netinet/in.h>
21 #include "byte-order.h"
22 #include "dynamic-string.h"
29 static struct cls_table *find_table(const struct classifier *,
30 const struct minimask *);
31 static struct cls_table *insert_table(struct classifier *,
32 const struct minimask *);
34 static void destroy_table(struct classifier *, struct cls_table *);
36 static void update_tables_after_insertion(struct classifier *,
38 unsigned int new_priority);
39 static void update_tables_after_removal(struct classifier *,
41 unsigned int del_priority);
43 static struct cls_rule *find_match(const struct cls_table *,
45 static struct cls_rule *find_equal(struct cls_table *,
46 const struct miniflow *, uint32_t hash);
47 static struct cls_rule *insert_rule(struct classifier *,
48 struct cls_table *, struct cls_rule *);
50 /* Iterates RULE over HEAD and all of the cls_rules on HEAD->list. */
51 #define FOR_EACH_RULE_IN_LIST(RULE, HEAD) \
52 for ((RULE) = (HEAD); (RULE) != NULL; (RULE) = next_rule_in_list(RULE))
53 #define FOR_EACH_RULE_IN_LIST_SAFE(RULE, NEXT, HEAD) \
54 for ((RULE) = (HEAD); \
55 (RULE) != NULL && ((NEXT) = next_rule_in_list(RULE), true); \
58 static struct cls_rule *next_rule_in_list__(struct cls_rule *);
59 static struct cls_rule *next_rule_in_list(struct cls_rule *);
63 /* Initializes 'rule' to match packets specified by 'match' at the given
64 * 'priority'. 'match' must satisfy the invariant described in the comment at
65 * the definition of struct match.
67 * The caller must eventually destroy 'rule' with cls_rule_destroy().
69 * (OpenFlow uses priorities between 0 and UINT16_MAX, inclusive, but
70 * internally Open vSwitch supports a wider range.) */
72 cls_rule_init(struct cls_rule *rule,
73 const struct match *match, unsigned int priority)
75 minimatch_init(&rule->match, match);
76 rule->priority = priority;
79 /* Same as cls_rule_init() for initialization from a "struct minimatch". */
81 cls_rule_init_from_minimatch(struct cls_rule *rule,
82 const struct minimatch *match,
83 unsigned int priority)
85 minimatch_clone(&rule->match, match);
86 rule->priority = priority;
89 /* Initializes 'dst' as a copy of 'src'.
91 * The caller must eventually destroy 'rule' with cls_rule_destroy(). */
93 cls_rule_clone(struct cls_rule *dst, const struct cls_rule *src)
95 minimatch_clone(&dst->match, &src->match);
96 dst->priority = src->priority;
99 /* Frees memory referenced by 'rule'. Doesn't free 'rule' itself (it's
100 * normally embedded into a larger structure).
102 * ('rule' must not currently be in a classifier.) */
104 cls_rule_destroy(struct cls_rule *rule)
106 minimatch_destroy(&rule->match);
109 /* Returns true if 'a' and 'b' match the same packets at the same priority,
110 * false if they differ in some way. */
112 cls_rule_equal(const struct cls_rule *a, const struct cls_rule *b)
114 return a->priority == b->priority && minimatch_equal(&a->match, &b->match);
117 /* Returns a hash value for 'rule', folding in 'basis'. */
119 cls_rule_hash(const struct cls_rule *rule, uint32_t basis)
121 return minimatch_hash(&rule->match, hash_int(rule->priority, basis));
124 /* Appends a string describing 'rule' to 's'. */
126 cls_rule_format(const struct cls_rule *rule, struct ds *s)
128 minimatch_format(&rule->match, s, rule->priority);
131 /* Returns true if 'rule' matches every packet, false otherwise. */
133 cls_rule_is_catchall(const struct cls_rule *rule)
135 return minimask_is_catchall(&rule->match.mask);
138 /* Initializes 'cls' as a classifier that initially contains no classification
141 classifier_init(struct classifier *cls)
144 hmap_init(&cls->tables);
145 list_init(&cls->tables_priority);
148 /* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
149 * caller's responsibility. */
151 classifier_destroy(struct classifier *cls)
154 struct cls_table *table, *next_table;
156 HMAP_FOR_EACH_SAFE (table, next_table, hmap_node, &cls->tables) {
157 destroy_table(cls, table);
159 hmap_destroy(&cls->tables);
163 /* Returns true if 'cls' contains no classification rules, false otherwise. */
165 classifier_is_empty(const struct classifier *cls)
167 return cls->n_rules == 0;
170 /* Returns the number of rules in 'cls'. */
172 classifier_count(const struct classifier *cls)
177 /* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller
178 * must not modify or free it.
180 * If 'cls' already contains an identical rule (including wildcards, values of
181 * fixed fields, and priority), replaces the old rule by 'rule' and returns the
182 * rule that was replaced. The caller takes ownership of the returned rule and
183 * is thus responsible for destroying it with cls_rule_destroy(), freeing the
184 * memory block in which it resides, etc., as necessary.
186 * Returns NULL if 'cls' does not contain a rule with an identical key, after
187 * inserting the new rule. In this case, no rules are displaced by the new
188 * rule, even rules that cannot have any effect because the new rule matches a
189 * superset of their flows and has higher priority. */
191 classifier_replace(struct classifier *cls, struct cls_rule *rule)
193 struct cls_rule *old_rule;
194 struct cls_table *table;
196 table = find_table(cls, &rule->match.mask);
198 table = insert_table(cls, &rule->match.mask);
201 old_rule = insert_rule(cls, table, rule);
203 table->n_table_rules++;
209 /* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller
210 * must not modify or free it.
212 * 'cls' must not contain an identical rule (including wildcards, values of
213 * fixed fields, and priority). Use classifier_find_rule_exactly() to find
216 classifier_insert(struct classifier *cls, struct cls_rule *rule)
218 struct cls_rule *displaced_rule = classifier_replace(cls, rule);
219 ovs_assert(!displaced_rule);
222 /* Removes 'rule' from 'cls'. It is the caller's responsibility to destroy
223 * 'rule' with cls_rule_destroy(), freeing the memory block in which 'rule'
224 * resides, etc., as necessary. */
226 classifier_remove(struct classifier *cls, struct cls_rule *rule)
228 struct cls_rule *head;
229 struct cls_table *table;
231 table = find_table(cls, &rule->match.mask);
232 head = find_equal(table, &rule->match.flow, rule->hmap_node.hash);
234 list_remove(&rule->list);
235 } else if (list_is_empty(&rule->list)) {
236 hmap_remove(&table->rules, &rule->hmap_node);
238 struct cls_rule *next = CONTAINER_OF(rule->list.next,
239 struct cls_rule, list);
241 list_remove(&rule->list);
242 hmap_replace(&table->rules, &rule->hmap_node, &next->hmap_node);
245 if (--table->n_table_rules == 0) {
246 destroy_table(cls, table);
248 update_tables_after_removal(cls, table, rule->priority);
253 /* Finds and returns the highest-priority rule in 'cls' that matches 'flow'.
254 * Returns a null pointer if no rules in 'cls' match 'flow'. If multiple rules
255 * of equal priority match 'flow', returns one arbitrarily.
257 * If a rule is found and 'wc' is non-null, bitwise-OR's 'wc' with the
258 * set of bits that were significant in the lookup. At some point
259 * earlier, 'wc' should have been initialized (e.g., by
260 * flow_wildcards_init_catchall()). */
262 classifier_lookup(const struct classifier *cls, const struct flow *flow,
263 struct flow_wildcards *wc)
265 struct cls_table *table;
266 struct cls_rule *best;
269 LIST_FOR_EACH (table, list_node, &cls->tables_priority) {
270 struct cls_rule *rule = find_match(table, flow);
273 flow_wildcards_fold_minimask(wc, &table->mask);
277 LIST_FOR_EACH_CONTINUE (table, list_node, &cls->tables_priority) {
278 if (table->max_priority <= best->priority) {
279 /* Tables in descending priority order,
280 * can not find anything better. */
283 rule = find_match(table, flow);
285 flow_wildcards_fold_minimask(wc, &table->mask);
287 if (rule && rule->priority > best->priority) {
297 /* Finds and returns a rule in 'cls' with exactly the same priority and
298 * matching criteria as 'target'. Returns a null pointer if 'cls' doesn't
299 * contain an exact match. */
301 classifier_find_rule_exactly(const struct classifier *cls,
302 const struct cls_rule *target)
304 struct cls_rule *head, *rule;
305 struct cls_table *table;
307 table = find_table(cls, &target->match.mask);
312 /* Skip if there is no hope. */
313 if (target->priority > table->max_priority) {
317 head = find_equal(table, &target->match.flow,
318 miniflow_hash_in_minimask(&target->match.flow,
319 &target->match.mask, 0));
320 FOR_EACH_RULE_IN_LIST (rule, head) {
321 if (target->priority >= rule->priority) {
322 return target->priority == rule->priority ? rule : NULL;
328 /* Finds and returns a rule in 'cls' with priority 'priority' and exactly the
329 * same matching criteria as 'target'. Returns a null pointer if 'cls' doesn't
330 * contain an exact match. */
332 classifier_find_match_exactly(const struct classifier *cls,
333 const struct match *target,
334 unsigned int priority)
336 struct cls_rule *retval;
339 cls_rule_init(&cr, target, priority);
340 retval = classifier_find_rule_exactly(cls, &cr);
341 cls_rule_destroy(&cr);
346 /* Checks if 'target' would overlap any other rule in 'cls'. Two rules are
347 * considered to overlap if both rules have the same priority and a packet
348 * could match both. */
350 classifier_rule_overlaps(const struct classifier *cls,
351 const struct cls_rule *target)
353 struct cls_table *table;
355 /* Iterate tables in the descending max priority order. */
356 LIST_FOR_EACH (table, list_node, &cls->tables_priority) {
357 uint32_t storage[FLOW_U32S];
358 struct minimask mask;
359 struct cls_rule *head;
361 if (target->priority > table->max_priority) {
362 break; /* Can skip this and the rest of the tables. */
365 minimask_combine(&mask, &target->match.mask, &table->mask, storage);
366 HMAP_FOR_EACH (head, hmap_node, &table->rules) {
367 struct cls_rule *rule;
369 FOR_EACH_RULE_IN_LIST (rule, head) {
370 if (rule->priority < target->priority) {
371 break; /* Rules in descending priority order. */
373 if (rule->priority == target->priority
374 && miniflow_equal_in_minimask(&target->match.flow,
375 &rule->match.flow, &mask)) {
385 /* Returns true if 'rule' exactly matches 'criteria' or if 'rule' is more
386 * specific than 'criteria'. That is, 'rule' matches 'criteria' and this
387 * function returns true if, for every field:
389 * - 'criteria' and 'rule' specify the same (non-wildcarded) value for the
392 * - 'criteria' wildcards the field,
394 * Conversely, 'rule' does not match 'criteria' and this function returns false
395 * if, for at least one field:
397 * - 'criteria' and 'rule' specify different values for the field, or
399 * - 'criteria' specifies a value for the field but 'rule' wildcards it.
401 * Equivalently, the truth table for whether a field matches is:
406 * r +---------+---------+
407 * i wild | yes | yes |
409 * e +---------+---------+
410 * r exact | no |if values|
412 * a +---------+---------+
414 * This is the matching rule used by OpenFlow 1.0 non-strict OFPT_FLOW_MOD
415 * commands and by OpenFlow 1.0 aggregate and flow stats.
417 * Ignores rule->priority. */
419 cls_rule_is_loose_match(const struct cls_rule *rule,
420 const struct minimatch *criteria)
422 return (!minimask_has_extra(&rule->match.mask, &criteria->mask)
423 && miniflow_equal_in_minimask(&rule->match.flow, &criteria->flow,
430 rule_matches(const struct cls_rule *rule, const struct cls_rule *target)
433 || miniflow_equal_in_minimask(&rule->match.flow,
435 &target->match.mask));
438 static struct cls_rule *
439 search_table(const struct cls_table *table, const struct cls_rule *target)
441 if (!target || !minimask_has_extra(&table->mask, &target->match.mask)) {
442 struct cls_rule *rule;
444 HMAP_FOR_EACH (rule, hmap_node, &table->rules) {
445 if (rule_matches(rule, target)) {
453 /* Initializes 'cursor' for iterating through rules in 'cls':
455 * - If 'target' is null, the cursor will visit every rule in 'cls'.
457 * - If 'target' is nonnull, the cursor will visit each 'rule' in 'cls'
458 * such that cls_rule_is_loose_match(rule, target) returns true.
460 * Ignores target->priority. */
462 cls_cursor_init(struct cls_cursor *cursor, const struct classifier *cls,
463 const struct cls_rule *target)
466 cursor->target = target && !cls_rule_is_catchall(target) ? target : NULL;
469 /* Returns the first matching cls_rule in 'cursor''s iteration, or a null
470 * pointer if there are no matches. */
472 cls_cursor_first(struct cls_cursor *cursor)
474 struct cls_table *table;
476 HMAP_FOR_EACH (table, hmap_node, &cursor->cls->tables) {
477 struct cls_rule *rule = search_table(table, cursor->target);
479 cursor->table = table;
487 /* Returns the next matching cls_rule in 'cursor''s iteration, or a null
488 * pointer if there are no more matches. */
490 cls_cursor_next(struct cls_cursor *cursor, struct cls_rule *rule)
492 const struct cls_table *table;
493 struct cls_rule *next;
495 next = next_rule_in_list__(rule);
496 if (next->priority < rule->priority) {
500 /* 'next' is the head of the list, that is, the rule that is included in
501 * the table's hmap. (This is important when the classifier contains rules
502 * that differ only in priority.) */
504 HMAP_FOR_EACH_CONTINUE (rule, hmap_node, &cursor->table->rules) {
505 if (rule_matches(rule, cursor->target)) {
510 table = cursor->table;
511 HMAP_FOR_EACH_CONTINUE (table, hmap_node, &cursor->cls->tables) {
512 rule = search_table(table, cursor->target);
514 cursor->table = table;
522 static struct cls_table *
523 find_table(const struct classifier *cls, const struct minimask *mask)
525 struct cls_table *table;
527 HMAP_FOR_EACH_IN_BUCKET (table, hmap_node, minimask_hash(mask, 0),
529 if (minimask_equal(mask, &table->mask)) {
536 static struct cls_table *
537 insert_table(struct classifier *cls, const struct minimask *mask)
539 struct cls_table *table;
541 table = xzalloc(sizeof *table);
542 hmap_init(&table->rules);
543 minimask_clone(&table->mask, mask);
544 hmap_insert(&cls->tables, &table->hmap_node, minimask_hash(mask, 0));
545 list_push_back(&cls->tables_priority, &table->list_node);
551 destroy_table(struct classifier *cls, struct cls_table *table)
553 minimask_destroy(&table->mask);
554 hmap_remove(&cls->tables, &table->hmap_node);
555 hmap_destroy(&table->rules);
556 list_remove(&table->list_node);
560 /* This function performs the following updates for 'table' in 'cls' following
561 * the addition of a new rule with priority 'new_priority' to 'table':
563 * - Update 'table->max_priority' and 'table->max_count' if necessary.
565 * - Update 'table''s position in 'cls->tables_priority' if necessary.
567 * This function should only be called after adding a new rule, not after
568 * replacing a rule by an identical one or modifying a rule in-place. */
570 update_tables_after_insertion(struct classifier *cls, struct cls_table *table,
571 unsigned int new_priority)
573 if (new_priority == table->max_priority) {
575 } else if (new_priority > table->max_priority) {
576 struct cls_table *iter;
578 table->max_priority = new_priority;
579 table->max_count = 1;
581 /* Possibly move 'table' earlier in the priority list. If we break out
582 * of the loop, then 'table' should be moved just after that 'iter'.
583 * If the loop terminates normally, then 'iter' will be the list head
584 * and we'll move table just after that (e.g. to the front of the
587 LIST_FOR_EACH_REVERSE_CONTINUE (iter, list_node,
588 &cls->tables_priority) {
589 if (iter->max_priority >= table->max_priority) {
594 /* Move 'table' just after 'iter' (unless it's already there). */
595 if (iter->list_node.next != &table->list_node) {
596 list_splice(iter->list_node.next,
597 &table->list_node, table->list_node.next);
602 /* This function performs the following updates for 'table' in 'cls' following
603 * the deletion of a rule with priority 'del_priority' from 'table':
605 * - Update 'table->max_priority' and 'table->max_count' if necessary.
607 * - Update 'table''s position in 'cls->tables_priority' if necessary.
609 * This function should only be called after removing a rule, not after
610 * replacing a rule by an identical one or modifying a rule in-place. */
612 update_tables_after_removal(struct classifier *cls, struct cls_table *table,
613 unsigned int del_priority)
615 struct cls_table *iter;
617 if (del_priority == table->max_priority && --table->max_count == 0) {
618 struct cls_rule *head;
620 table->max_priority = 0;
621 HMAP_FOR_EACH (head, hmap_node, &table->rules) {
622 if (head->priority > table->max_priority) {
623 table->max_priority = head->priority;
624 table->max_count = 1;
625 } else if (head->priority == table->max_priority) {
630 /* Possibly move 'table' later in the priority list. If we break out
631 * of the loop, then 'table' should be moved just before that 'iter'.
632 * If the loop terminates normally, then 'iter' will be the list head
633 * and we'll move table just before that (e.g. to the back of the
636 LIST_FOR_EACH_CONTINUE (iter, list_node, &cls->tables_priority) {
637 if (iter->max_priority <= table->max_priority) {
642 /* Move 'table' just before 'iter' (unless it's already there). */
643 if (iter->list_node.prev != &table->list_node) {
644 list_splice(&iter->list_node,
645 &table->list_node, table->list_node.next);
650 static struct cls_rule *
651 find_match(const struct cls_table *table, const struct flow *flow)
653 uint32_t hash = flow_hash_in_minimask(flow, &table->mask, 0);
654 struct cls_rule *rule;
656 HMAP_FOR_EACH_WITH_HASH (rule, hmap_node, hash, &table->rules) {
657 if (miniflow_equal_flow_in_minimask(&rule->match.flow, flow,
666 static struct cls_rule *
667 find_equal(struct cls_table *table, const struct miniflow *flow, uint32_t hash)
669 struct cls_rule *head;
671 HMAP_FOR_EACH_WITH_HASH (head, hmap_node, hash, &table->rules) {
672 if (miniflow_equal(&head->match.flow, flow)) {
679 static struct cls_rule *
680 insert_rule(struct classifier *cls,
681 struct cls_table *table, struct cls_rule *new)
683 struct cls_rule *head;
684 struct cls_rule *old = NULL;
686 new->hmap_node.hash = miniflow_hash_in_minimask(&new->match.flow,
687 &new->match.mask, 0);
689 head = find_equal(table, &new->match.flow, new->hmap_node.hash);
691 hmap_insert(&table->rules, &new->hmap_node, new->hmap_node.hash);
692 list_init(&new->list);
695 /* Scan the list for the insertion point that will keep the list in
696 * order of decreasing priority. */
697 struct cls_rule *rule;
698 FOR_EACH_RULE_IN_LIST (rule, head) {
699 if (new->priority >= rule->priority) {
701 /* 'new' is the new highest-priority flow in the list. */
702 hmap_replace(&table->rules,
703 &rule->hmap_node, &new->hmap_node);
706 if (new->priority == rule->priority) {
707 list_replace(&new->list, &rule->list);
711 list_insert(&rule->list, &new->list);
717 /* Insert 'new' at the end of the list. */
718 list_push_back(&head->list, &new->list);
723 update_tables_after_insertion(cls, table, new->priority);
728 static struct cls_rule *
729 next_rule_in_list__(struct cls_rule *rule)
731 struct cls_rule *next = OBJECT_CONTAINING(rule->list.next, next, list);
735 static struct cls_rule *
736 next_rule_in_list(struct cls_rule *rule)
738 struct cls_rule *next = next_rule_in_list__(rule);
739 return next->priority < rule->priority ? next : NULL;