lib/classifier.h

   1 /*
   2  * Copyright (c) 2009, 2010, 2011, 2012 Nicira, Inc.
   3  *
   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:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  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.
  15  */
  16
  17 #ifndef CLASSIFIER_H
  18 #define CLASSIFIER_H 1
  19
  20 /* Flow classifier.
  21  *
  22  * A classifier is a "struct classifier",
  23  *      a hash map from a set of wildcards to a "struct cls_table",
  24  *              a hash map from fixed field values to "struct cls_rule",
  25  *                      which can contain a list of otherwise identical rules
  26  *                      with lower priorities.
  27  *
  28  * Thread-safety
  29  * =============
  30  *
  31  * When locked properly, the classifier is thread safe as long as the following
  32  * conditions are satisfied.
  33  * - Only the main thread calls functions requiring a write lock.
  34  * - Only the main thread is allowed to iterate over rules. */
  35
  36 #include "flow.h"
  37 #include "hmap.h"
  38 #include "list.h"
  39 #include "match.h"
  40 #include "openflow/nicira-ext.h"
  41 #include "openflow/openflow.h"
  42 #include "ovs-thread.h"
  43 #include "util.h"
  44
  45 #ifdef __cplusplus
  46 extern "C" {
  47 #endif
  48
  49 /* A flow classifier. */
  50 struct classifier {
  51     int n_rules;                /* Total number of rules. */
  52     struct hmap tables;         /* Contains "struct cls_table"s.  */
  53     struct list tables_priority; /* Tables in descending priority order */
  54     struct ovs_rwlock rwlock;
  55 };
  56
  57 /* A set of rules that all have the same fields wildcarded. */
  58 struct cls_table {
  59     struct hmap_node hmap_node; /* Within struct classifier 'tables' hmap. */
  60     struct list list_node;      /* Within classifier 'tables_priority_list' */
  61     struct hmap rules;          /* Contains "struct cls_rule"s. */
  62     struct minimask mask;       /* Wildcards for fields. */
  63     int n_table_rules;          /* Number of rules, including duplicates. */
  64     unsigned int max_priority;  /* Max priority of any rule in the table. */
  65     unsigned int max_count;     /* Count of max_priority rules. */
  66 };
  67
  68 /* Returns true if 'table' is a "catch-all" table that will match every
  69  * packet (if there is no higher-priority match). */
  70 static inline bool
  71 cls_table_is_catchall(const struct cls_table *table)
  72 {
  73     return minimask_is_catchall(&table->mask);
  74 }
  75
  76 /* A rule in a "struct classifier". */
  77 struct cls_rule {
  78     struct hmap_node hmap_node; /* Within struct cls_table 'rules'. */
  79     struct list list;           /* List of identical, lower-priority rules. */
  80     struct minimatch match;     /* Matching rule. */
  81     unsigned int priority;      /* Larger numbers are higher priorities. */
  82 };
  83
  84 void cls_rule_init(struct cls_rule *, const struct match *,
  85                    unsigned int priority);
  86 void cls_rule_init_from_minimatch(struct cls_rule *, const struct minimatch *,
  87                                   unsigned int priority);
  88 void cls_rule_clone(struct cls_rule *, const struct cls_rule *);
  89 void cls_rule_destroy(struct cls_rule *);
  90
  91 bool cls_rule_equal(const struct cls_rule *, const struct cls_rule *);
  92 uint32_t cls_rule_hash(const struct cls_rule *, uint32_t basis);
  93
  94 void cls_rule_format(const struct cls_rule *, struct ds *);
  95
  96 bool cls_rule_is_catchall(const struct cls_rule *);
  97
  98 bool cls_rule_is_loose_match(const struct cls_rule *rule,
  99                              const struct minimatch *criteria);
 100
 101 void classifier_init(struct classifier *cls);
 102 void classifier_destroy(struct classifier *);
 103 bool classifier_is_empty(const struct classifier *cls)
 104     OVS_REQ_RDLOCK(cls->rwlock);
 105 int classifier_count(const struct classifier *cls)
 106     OVS_REQ_RDLOCK(cls->rwlock);
 107 void classifier_insert(struct classifier *cls, struct cls_rule *)
 108     OVS_REQ_WRLOCK(cls->rwlock);
 109 struct cls_rule *classifier_replace(struct classifier *cls, struct cls_rule *)
 110     OVS_REQ_WRLOCK(cls->rwlock);
 111 void classifier_remove(struct classifier *cls, struct cls_rule *)
 112     OVS_REQ_WRLOCK(cls->rwlock);
 113 struct cls_rule *classifier_lookup(const struct classifier *cls,
 114                                    const struct flow *,
 115                                    struct flow_wildcards *)
 116     OVS_REQ_RDLOCK(cls->rwlock);
 117 bool classifier_rule_overlaps(const struct classifier *cls,
 118                               const struct cls_rule *)
 119     OVS_REQ_RDLOCK(cls->rwlock);
 120
 121 typedef void cls_cb_func(struct cls_rule *, void *aux);
 122
 123 struct cls_rule *classifier_find_rule_exactly(const struct classifier *cls,
 124                                               const struct cls_rule *)
 125     OVS_REQ_RDLOCK(cls->rwlock);
 126 struct cls_rule *classifier_find_match_exactly(const struct classifier *cls,
 127                                                const struct match *,
 128                                                unsigned int priority)
 129     OVS_REQ_RDLOCK(cls->rwlock);
 130 \f
 131 /* Iteration. */
 132
 133 struct cls_cursor {
 134     const struct classifier *cls;
 135     const struct cls_table *table;
 136     const struct cls_rule *target;
 137 };
 138
 139 void cls_cursor_init(struct cls_cursor *cursor, const struct classifier *cls,
 140                      const struct cls_rule *match) OVS_REQ_RDLOCK(cls->rwlock);
 141 struct cls_rule *cls_cursor_first(struct cls_cursor *cursor);
 142 struct cls_rule *cls_cursor_next(struct cls_cursor *cursor, struct cls_rule *);
 143
 144 #define CLS_CURSOR_FOR_EACH(RULE, MEMBER, CURSOR)                       \
 145     for (ASSIGN_CONTAINER(RULE, cls_cursor_first(CURSOR), MEMBER);      \
 146          RULE != OBJECT_CONTAINING(NULL, RULE, MEMBER);                 \
 147          ASSIGN_CONTAINER(RULE, cls_cursor_next(CURSOR, &(RULE)->MEMBER), \
 148                           MEMBER))
 149
 150 #define CLS_CURSOR_FOR_EACH_SAFE(RULE, NEXT, MEMBER, CURSOR)            \
 151     for (ASSIGN_CONTAINER(RULE, cls_cursor_first(CURSOR), MEMBER);      \
 152          (RULE != OBJECT_CONTAINING(NULL, RULE, MEMBER)                 \
 153           ? ASSIGN_CONTAINER(NEXT, cls_cursor_next(CURSOR, &(RULE)->MEMBER), \
 154                              MEMBER), 1                                 \
 155           : 0);                                                         \
 156          (RULE) = (NEXT))
 157
 158 #ifdef __cplusplus
 159 }
 160 #endif
 161
 162 #endif /* classifier.h */