*
* This is how the classifier works. In a "struct classifier", each form of
* "struct cls_rule" present (based on its ->match.mask) goes into a separate
- * "struct cls_table". A lookup does a hash lookup in every "struct cls_table"
- * in the classifier and tracks the highest-priority match that it finds. The
- * tables are kept in a descending priority order according to the highest
- * priority rule in each table, which allows lookup to skip over tables that
- * can't possibly have a higher-priority match than already found.
+ * "struct cls_subtable". A lookup does a hash lookup in every "struct
+ * cls_subtable" in the classifier and tracks the highest-priority match that
+ * it finds. The subtables are kept in a descending priority order according
+ * to the highest priority rule in each subtable, which allows lookup to skip
+ * over subtables that can't possibly have a higher-priority match than
+ * already found.
*
* One detail: a classifier can contain multiple rules that are identical other
* than their priority. When this happens, only the highest priority rule out
* of a group of otherwise identical rules is stored directly in the "struct
- * cls_table", with the other almost-identical rules chained off a linked list
- * inside that highest-priority rule.
+ * cls_subtable", with the other almost-identical rules chained off a linked
+ * list inside that highest-priority rule.
+ *
+ *
+ * Staged Lookup
+ * =============
+ *
+ * Subtable lookup is performed in ranges defined for struct flow, starting
+ * from metadata (registers, in_port, etc.), then L2 header, L3, and finally
+ * L4 ports. Whenever it is found that there are no matches in the current
+ * subtable, the rest of the subtable can be skipped. The rationale of this
+ * logic is that as many fields as possible can remain wildcarded.
*
*
* Partitioning
* The classifier has a special optimization to speed up matching in this
* scenario:
*
- * - Each cls_table that matches on metadata gets a tag derived from the
- * table's mask, so that it is likely that each table has a unique tag.
- * (Duplicate tags have a performance cost but do not affect
+ * - Each cls_subtable that matches on metadata gets a tag derived from the
+ * subtable's mask, so that it is likely that each subtable has a unique
+ * tag. (Duplicate tags have a performance cost but do not affect
* correctness.)
*
* - For each metadata value matched by any cls_rule, the classifier
* constructs a "struct cls_partition" indexed by the metadata value.
* The cls_partition has a 'tags' member whose value is the bitwise-OR of
- * the tags of each cls_table that contains any rule that matches on the
- * cls_partition's metadata value. In other words, struct cls_partition
- * associates metadata values with tables that need to be checked with
- * flows with that specific metadata value.
+ * the tags of each cls_subtable that contains any rule that matches on
+ * the cls_partition's metadata value. In other words, struct
+ * cls_partition associates metadata values with subtables that need to
+ * be checked with flows with that specific metadata value.
*
* Thus, a flow lookup can start by looking up the partition associated with
- * the flow's metadata, and then skip over any cls_table whose 'tag' does not
- * intersect the partition's 'tags'. (The flow must also be looked up in any
- * cls_table that doesn't match on metadata. We handle that by giving any such
- * cls_table TAG_ALL as its 'tags' so that it matches any tag.)
+ * the flow's metadata, and then skip over any cls_subtable whose 'tag' does
+ * not intersect the partition's 'tags'. (The flow must also be looked up in
+ * any cls_subtable that doesn't match on metadata. We handle that by giving
+ * any such cls_subtable TAG_ALL as its 'tags' so that it matches any tag.)
*
*
* Thread-safety
* =============
*
- * When locked properly, the classifier is thread safe as long as the following
- * conditions are satisfied.
- * - Only the main thread calls functions requiring a write lock.
- * - Only the main thread is allowed to iterate over rules. */
+ * The classifier may safely be accessed by many reader threads concurrently or
+ * by a single writer. */
#include "flow.h"
+#include "hindex.h"
#include "hmap.h"
#include "list.h"
#include "match.h"
/* Needed only for the lock annotation in struct classifier. */
extern struct ovs_mutex ofproto_mutex;
+/* Maximum number of staged lookup indices for each subtable. */
+enum { CLS_MAX_INDICES = 3 };
+
/* A flow classifier. */
struct classifier {
int n_rules; /* Total number of rules. */
- struct hmap tables; /* Contains "struct cls_table"s. */
- struct list tables_priority; /* Tables in descending priority order */
+ uint8_t n_flow_segments;
+ uint8_t flow_segments[CLS_MAX_INDICES]; /* Flow segment boundaries to use
+ * for staged lookup. */
+ struct hmap subtables; /* Contains "struct cls_subtable"s. */
+ struct list subtables_priority; /* Subtables in descending priority order.
+ */
struct hmap partitions; /* Contains "struct cls_partition"s. */
struct ovs_rwlock rwlock OVS_ACQ_AFTER(ofproto_mutex);
};
/* A set of rules that all have the same fields wildcarded. */
-struct cls_table {
- struct hmap_node hmap_node; /* Within struct classifier 'tables' hmap. */
- struct list list_node; /* Within classifier 'tables_priority_list' */
+struct cls_subtable {
+ struct hmap_node hmap_node; /* Within struct classifier 'subtables' hmap.
+ */
+ struct list list_node; /* Within classifier 'subtables_priority' list.
+ */
struct hmap rules; /* Contains "struct cls_rule"s. */
struct minimask mask; /* Wildcards for fields. */
- int n_table_rules; /* Number of rules, including duplicates. */
- unsigned int max_priority; /* Max priority of any rule in the table. */
+ int n_rules; /* Number of rules, including duplicates. */
+ unsigned int max_priority; /* Max priority of any rule in the subtable. */
unsigned int max_count; /* Count of max_priority rules. */
tag_type tag; /* Tag generated from mask for partitioning. */
+ uint8_t n_indices; /* How many indices to use. */
+ uint8_t index_ofs[CLS_MAX_INDICES]; /* u32 flow segment boundaries. */
+ struct hindex indices[CLS_MAX_INDICES]; /* Staged lookup indices. */
};
-/* Returns true if 'table' is a "catch-all" table that will match every
+/* Returns true if 'table' is a "catch-all" subtable that will match every
* packet (if there is no higher-priority match). */
static inline bool
-cls_table_is_catchall(const struct cls_table *table)
+cls_subtable_is_catchall(const struct cls_subtable *subtable)
{
- return minimask_is_catchall(&table->mask);
+ return minimask_is_catchall(&subtable->mask);
}
-/* A rule in a "struct classifier". */
+/* A rule in a "struct cls_subtable". */
struct cls_rule {
- struct hmap_node hmap_node; /* Within struct cls_table 'rules'. */
+ struct hmap_node hmap_node; /* Within struct cls_subtable 'rules'. */
struct list list; /* List of identical, lower-priority rules. */
struct minimatch match; /* Matching rule. */
unsigned int priority; /* Larger numbers are higher priorities. */
struct cls_partition *partition;
+ struct hindex_node index_nodes[CLS_MAX_INDICES]; /* Within subtable's
+ * 'indices'. */
};
/* Associates a metadata value (that is, a value of the OpenFlow 1.1+ metadata
- * field) with tags for the "cls_table"s that contain rules that match that
+ * field) with tags for the "cls_subtable"s that contain rules that match that
* metadata value. */
struct cls_partition {
struct hmap_node hmap_node; /* In struct classifier's 'partitions' hmap. */
ovs_be64 metadata; /* metadata value for this partition. */
- tag_type tags; /* OR of each included flow's cls_table tag. */
+ tag_type tags; /* OR of each flow's cls_subtable tag. */
struct tag_tracker tracker; /* Tracks the bits in 'tags'. */
};
bool cls_rule_is_loose_match(const struct cls_rule *rule,
const struct minimatch *criteria);
-void classifier_init(struct classifier *cls);
+void classifier_init(struct classifier *cls, const uint8_t *flow_segments);
void classifier_destroy(struct classifier *);
bool classifier_is_empty(const struct classifier *cls)
OVS_REQ_RDLOCK(cls->rwlock);
struct cls_cursor {
const struct classifier *cls;
- const struct cls_table *table;
+ const struct cls_subtable *subtable;
const struct cls_rule *target;
};
void cls_cursor_init(struct cls_cursor *cursor, const struct classifier *cls,
const struct cls_rule *match) OVS_REQ_RDLOCK(cls->rwlock);
struct cls_rule *cls_cursor_first(struct cls_cursor *cursor);
-struct cls_rule *cls_cursor_next(struct cls_cursor *cursor, const struct cls_rule *);
+struct cls_rule *cls_cursor_next(struct cls_cursor *, const struct cls_rule *);
#define CLS_CURSOR_FOR_EACH(RULE, MEMBER, CURSOR) \
for (ASSIGN_CONTAINER(RULE, cls_cursor_first(CURSOR), MEMBER); \
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