/*
- * Copyright (c) 2009, 2010 Nicira Networks.
+ * Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <config.h>
#include "classifier.h"
-#include <assert.h>
#include <errno.h>
#include <netinet/in.h>
+#include "byte-order.h"
+#include "dynamic-string.h"
#include "flow.h"
#include "hash.h"
+#include "odp-util.h"
+#include "ofp-util.h"
+#include "ovs-thread.h"
+#include "packets.h"
+#include "vlog.h"
+
+VLOG_DEFINE_THIS_MODULE(classifier);
+
+struct trie_ctx;
+static struct cls_subtable *find_subtable(const struct classifier *,
+ const struct minimask *);
+static struct cls_subtable *insert_subtable(struct classifier *,
+ const struct minimask *);
+
+static void destroy_subtable(struct classifier *, struct cls_subtable *);
+
+static void update_subtables_after_insertion(struct classifier *,
+ struct cls_subtable *,
+ unsigned int new_priority);
+static void update_subtables_after_removal(struct classifier *,
+ struct cls_subtable *,
+ unsigned int del_priority);
+
+static struct cls_rule *find_match_wc(const struct cls_subtable *,
+ const struct flow *, struct trie_ctx *,
+ unsigned int n_tries,
+ struct flow_wildcards *);
+static struct cls_rule *find_equal(struct cls_subtable *,
+ const struct miniflow *, uint32_t hash);
+static struct cls_rule *insert_rule(struct classifier *,
+ struct cls_subtable *, struct cls_rule *);
+
+/* Iterates RULE over HEAD and all of the cls_rules on HEAD->list. */
+#define FOR_EACH_RULE_IN_LIST(RULE, HEAD) \
+ for ((RULE) = (HEAD); (RULE) != NULL; (RULE) = next_rule_in_list(RULE))
+#define FOR_EACH_RULE_IN_LIST_SAFE(RULE, NEXT, HEAD) \
+ for ((RULE) = (HEAD); \
+ (RULE) != NULL && ((NEXT) = next_rule_in_list(RULE), true); \
+ (RULE) = (NEXT))
+
+static struct cls_rule *next_rule_in_list__(struct cls_rule *);
+static struct cls_rule *next_rule_in_list(struct cls_rule *);
+
+static unsigned int minimask_get_prefix_len(const struct minimask *,
+ const struct mf_field *);
+static void trie_init(struct classifier *, int trie_idx,
+ const struct mf_field *);
+static unsigned int trie_lookup(const struct cls_trie *, const struct flow *,
+ unsigned int *checkbits);
+
+static void trie_destroy(struct trie_node *);
+static void trie_insert(struct cls_trie *, const struct cls_rule *, int mlen);
+static void trie_remove(struct cls_trie *, const struct cls_rule *, int mlen);
+static void mask_set_prefix_bits(struct flow_wildcards *, uint8_t be32ofs,
+ unsigned int nbits);
+static bool mask_prefix_bits_set(const struct flow_wildcards *,
+ uint8_t be32ofs, unsigned int nbits);
+\f
+/* cls_rule. */
-const struct cls_field cls_fields[CLS_N_FIELDS + 1] = {
-#define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
- { offsetof(flow_t, MEMBER), \
- sizeof ((flow_t *)0)->MEMBER, \
- WILDCARDS, \
- #NAME },
- CLS_FIELDS
-#undef CLS_FIELD
- { sizeof(flow_t), 0, 0, "exact" },
-};
-
-static uint32_t hash_fields(const flow_t *, int table_idx);
-static bool equal_fields(const flow_t *, const flow_t *, int table_idx);
-
-static int table_idx_from_wildcards(uint32_t wildcards);
-static struct cls_rule *table_insert(struct hmap *, struct cls_rule *);
-static struct cls_rule *insert_exact_rule(struct classifier *,
- struct cls_rule *);
-static struct cls_bucket *find_bucket(struct hmap *, size_t hash,
- const struct cls_rule *);
-static struct cls_rule *search_table(const struct hmap *table, int field_idx,
- const struct cls_rule *);
-static struct cls_rule *search_exact_table(const struct classifier *,
- size_t hash, const flow_t *);
-static bool rules_match_1wild(const struct cls_rule *fixed,
- const struct cls_rule *wild, int field_idx);
-
-/* Converts the flow in 'flow' into a cls_rule in 'rule', with the given
- * 'wildcards' and 'priority'.*/
+/* Initializes 'rule' to match packets specified by 'match' at the given
+ * 'priority'. 'match' must satisfy the invariant described in the comment at
+ * the definition of struct match.
+ *
+ * The caller must eventually destroy 'rule' with cls_rule_destroy().
+ *
+ * (OpenFlow uses priorities between 0 and UINT16_MAX, inclusive, but
+ * internally Open vSwitch supports a wider range.) */
void
-cls_rule_from_flow(struct cls_rule *rule, const flow_t *flow,
- uint32_t wildcards, unsigned int priority)
+cls_rule_init(struct cls_rule *rule,
+ const struct match *match, unsigned int priority)
{
- assert(flow->reserved == 0);
- rule->flow = *flow;
- flow_wildcards_init(&rule->wc, wildcards);
+ minimatch_init(&rule->match, match);
rule->priority = priority;
- rule->table_idx = table_idx_from_wildcards(rule->wc.wildcards);
}
-/* Converts the ofp_match in 'match' into a cls_rule in 'rule', with the given
- * 'priority'. */
+/* Same as cls_rule_init() for initialization from a "struct minimatch". */
void
-cls_rule_from_match(struct cls_rule *rule, const struct ofp_match *match,
- unsigned int priority)
+cls_rule_init_from_minimatch(struct cls_rule *rule,
+ const struct minimatch *match,
+ unsigned int priority)
{
- uint32_t wildcards;
- flow_from_match(&rule->flow, &wildcards, match);
- flow_wildcards_init(&rule->wc, wildcards);
- rule->priority = rule->wc.wildcards ? priority : UINT16_MAX;
- rule->table_idx = table_idx_from_wildcards(rule->wc.wildcards);
+ minimatch_clone(&rule->match, match);
+ rule->priority = priority;
}
-/* Prints cls_rule 'rule', for debugging.
+/* Initializes 'dst' as a copy of 'src'.
*
- * (The output could be improved and expanded, but this was good enough to
- * debug the classifier.) */
+ * The caller must eventually destroy 'dst' with cls_rule_destroy(). */
void
-cls_rule_print(const struct cls_rule *rule)
+cls_rule_clone(struct cls_rule *dst, const struct cls_rule *src)
{
- printf("wildcards=%x priority=%u ", rule->wc.wildcards, rule->priority);
- flow_print(stdout, &rule->flow);
- putc('\n', stdout);
+ minimatch_clone(&dst->match, &src->match);
+ dst->priority = src->priority;
}
-/* Adjusts pointers around 'old', which must be in classifier 'cls', to
- * compensate for it having been moved in memory to 'new' (e.g. due to
- * realloc()).
+/* Initializes 'dst' with the data in 'src', destroying 'src'.
*
- * This function cannot be realized in all possible flow classifier
- * implementations, so we will probably have to change the interface if we
- * change the implementation. Shouldn't be a big deal though. */
+ * The caller must eventually destroy 'dst' with cls_rule_destroy(). */
void
-cls_rule_moved(struct classifier *cls, struct cls_rule *old,
- struct cls_rule *new)
+cls_rule_move(struct cls_rule *dst, struct cls_rule *src)
{
- if (old != new) {
- if (new->wc.wildcards) {
- list_moved(&new->node.list);
- } else {
- hmap_node_moved(&cls->exact_table,
- &old->node.hmap, &new->node.hmap);
- }
- }
+ minimatch_move(&dst->match, &src->match);
+ dst->priority = src->priority;
}
-/* Replaces 'old', which must be in classifier 'cls', by 'new' (e.g. due to
- * realloc()); that is, after calling this function 'new' will be in 'cls' in
- * place of 'old'.
- *
- * 'new' and 'old' must be exactly the same: wildcard the same fields, have the
- * same fixed values for non-wildcarded fields, and have the same priority.
+/* Frees memory referenced by 'rule'. Doesn't free 'rule' itself (it's
+ * normally embedded into a larger structure).
*
- * The caller takes ownership of 'old' and is thus responsible for freeing it,
- * etc., as necessary.
- *
- * This function cannot be realized in all possible flow classifier
- * implementations, so we will probably have to change the interface if we
- * change the implementation. Shouldn't be a big deal though. */
+ * ('rule' must not currently be in a classifier.) */
void
-cls_rule_replace(struct classifier *cls, const struct cls_rule *old,
- struct cls_rule *new)
+cls_rule_destroy(struct cls_rule *rule)
{
- assert(old != new);
- assert(old->wc.wildcards == new->wc.wildcards);
- assert(old->priority == new->priority);
+ minimatch_destroy(&rule->match);
+}
- if (new->wc.wildcards) {
- list_replace(&new->node.list, &old->node.list);
- } else {
- hmap_replace(&cls->exact_table, &old->node.hmap, &new->node.hmap);
- }
+/* Returns true if 'a' and 'b' match the same packets at the same priority,
+ * false if they differ in some way. */
+bool
+cls_rule_equal(const struct cls_rule *a, const struct cls_rule *b)
+{
+ return a->priority == b->priority && minimatch_equal(&a->match, &b->match);
+}
+
+/* Returns a hash value for 'rule', folding in 'basis'. */
+uint32_t
+cls_rule_hash(const struct cls_rule *rule, uint32_t basis)
+{
+ return minimatch_hash(&rule->match, hash_int(rule->priority, basis));
+}
+
+/* Appends a string describing 'rule' to 's'. */
+void
+cls_rule_format(const struct cls_rule *rule, struct ds *s)
+{
+ minimatch_format(&rule->match, s, rule->priority);
+}
+
+/* Returns true if 'rule' matches every packet, false otherwise. */
+bool
+cls_rule_is_catchall(const struct cls_rule *rule)
+{
+ return minimask_is_catchall(&rule->match.mask);
}
\f
/* Initializes 'cls' as a classifier that initially contains no classification
* rules. */
void
-classifier_init(struct classifier *cls)
+classifier_init(struct classifier *cls, const uint8_t *flow_segments)
{
- int i;
-
cls->n_rules = 0;
- for (i = 0; i < ARRAY_SIZE(cls->tables); i++) {
- hmap_init(&cls->tables[i]);
+ hmap_init(&cls->subtables);
+ list_init(&cls->subtables_priority);
+ hmap_init(&cls->partitions);
+ fat_rwlock_init(&cls->rwlock);
+ cls->n_flow_segments = 0;
+ if (flow_segments) {
+ while (cls->n_flow_segments < CLS_MAX_INDICES
+ && *flow_segments < FLOW_U32S) {
+ cls->flow_segments[cls->n_flow_segments++] = *flow_segments++;
+ }
}
- hmap_init(&cls->exact_table);
+ cls->n_tries = 0;
}
/* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
classifier_destroy(struct classifier *cls)
{
if (cls) {
- struct cls_bucket *bucket, *next_bucket;
- struct hmap *tbl;
+ struct cls_subtable *partition, *next_partition;
+ struct cls_subtable *subtable, *next_subtable;
+ int i;
+
+ for (i = 0; i < cls->n_tries; i++) {
+ trie_destroy(cls->tries[i].root);
+ }
+
+ HMAP_FOR_EACH_SAFE (subtable, next_subtable, hmap_node,
+ &cls->subtables) {
+ destroy_subtable(cls, subtable);
+ }
+ hmap_destroy(&cls->subtables);
+
+ HMAP_FOR_EACH_SAFE (partition, next_partition, hmap_node,
+ &cls->partitions) {
+ hmap_remove(&cls->partitions, &partition->hmap_node);
+ free(partition);
+ }
+ hmap_destroy(&cls->partitions);
+ fat_rwlock_destroy(&cls->rwlock);
+ }
+}
+
+/* We use uint64_t as a set for the fields below. */
+BUILD_ASSERT_DECL(MFF_N_IDS <= 64);
+
+/* Set the fields for which prefix lookup should be performed. */
+void
+classifier_set_prefix_fields(struct classifier *cls,
+ const enum mf_field_id *trie_fields,
+ unsigned int n_fields)
+{
+ uint64_t fields = 0;
+ int i, trie;
+
+ for (i = 0, trie = 0; i < n_fields && trie < CLS_MAX_TRIES; i++) {
+ const struct mf_field *field = mf_from_id(trie_fields[i]);
+ if (field->flow_be32ofs < 0 || field->n_bits % 32) {
+ /* Incompatible field. This is the only place where we
+ * enforce these requirements, but the rest of the trie code
+ * depends on the flow_be32ofs to be non-negative and the
+ * field length to be a multiple of 32 bits. */
+ continue;
+ }
+
+ if (fields & (UINT64_C(1) << trie_fields[i])) {
+ /* Duplicate field, there is no need to build more than
+ * one index for any one field. */
+ continue;
+ }
+ fields |= UINT64_C(1) << trie_fields[i];
+
+ if (trie >= cls->n_tries || field != cls->tries[trie].field) {
+ trie_init(cls, trie, field);
+ }
+ trie++;
+ }
+
+ /* Destroy the rest. */
+ for (i = trie; i < cls->n_tries; i++) {
+ trie_init(cls, i, NULL);
+ }
+ cls->n_tries = trie;
+}
- for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
- HMAP_FOR_EACH_SAFE (bucket, next_bucket,
- struct cls_bucket, hmap_node, tbl) {
- free(bucket);
+static void
+trie_init(struct classifier *cls, int trie_idx,
+ const struct mf_field *field)
+{
+ struct cls_trie *trie = &cls->tries[trie_idx];
+ struct cls_subtable *subtable;
+
+ if (trie_idx < cls->n_tries) {
+ trie_destroy(trie->root);
+ }
+ trie->root = NULL;
+ trie->field = field;
+
+ /* Add existing rules to the trie. */
+ LIST_FOR_EACH (subtable, list_node, &cls->subtables_priority) {
+ unsigned int plen;
+
+ plen = field ? minimask_get_prefix_len(&subtable->mask, field) : 0;
+ /* Initialize subtable's prefix length on this field. */
+ subtable->trie_plen[trie_idx] = plen;
+
+ if (plen) {
+ struct cls_rule *head;
+
+ HMAP_FOR_EACH (head, hmap_node, &subtable->rules) {
+ struct cls_rule *rule;
+
+ FOR_EACH_RULE_IN_LIST (rule, head) {
+ trie_insert(trie, rule, plen);
+ }
}
- hmap_destroy(tbl);
}
- hmap_destroy(&cls->exact_table);
}
}
-/* Returns true if 'cls' does not contain any classification rules, false
- * otherwise. */
+/* Returns true if 'cls' contains no classification rules, false otherwise. */
bool
classifier_is_empty(const struct classifier *cls)
{
return cls->n_rules == 0;
}
-/* Returns the number of rules in 'classifier'. */
+/* Returns the number of rules in 'cls'. */
int
classifier_count(const struct classifier *cls)
{
return cls->n_rules;
}
-/* Returns the number of rules in 'classifier' that have no wildcards. */
-int
-classifier_count_exact(const struct classifier *cls)
+static uint32_t
+hash_metadata(ovs_be64 metadata_)
+{
+ uint64_t metadata = (OVS_FORCE uint64_t) metadata_;
+ return hash_uint64(metadata);
+}
+
+static struct cls_partition *
+find_partition(const struct classifier *cls, ovs_be64 metadata, uint32_t hash)
+{
+ struct cls_partition *partition;
+
+ HMAP_FOR_EACH_IN_BUCKET (partition, hmap_node, hash, &cls->partitions) {
+ if (partition->metadata == metadata) {
+ return partition;
+ }
+ }
+
+ return NULL;
+}
+
+static struct cls_partition *
+create_partition(struct classifier *cls, struct cls_subtable *subtable,
+ ovs_be64 metadata)
{
- return hmap_count(&cls->exact_table);
+ uint32_t hash = hash_metadata(metadata);
+ struct cls_partition *partition = find_partition(cls, metadata, hash);
+ if (!partition) {
+ partition = xmalloc(sizeof *partition);
+ partition->metadata = metadata;
+ partition->tags = 0;
+ tag_tracker_init(&partition->tracker);
+ hmap_insert(&cls->partitions, &partition->hmap_node, hash);
+ }
+ tag_tracker_add(&partition->tracker, &partition->tags, subtable->tag);
+ return partition;
}
-/* Inserts 'rule' into 'cls'. Transfers ownership of 'rule' to 'cls'.
+/* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller
+ * must not modify or free it.
*
* If 'cls' already contains an identical rule (including wildcards, values of
* fixed fields, and priority), replaces the old rule by 'rule' and returns the
* rule that was replaced. The caller takes ownership of the returned rule and
- * is thus responsible for freeing it, etc., as necessary.
+ * is thus responsible for destroying it with cls_rule_destroy(), freeing the
+ * memory block in which it resides, etc., as necessary.
*
* Returns NULL if 'cls' does not contain a rule with an identical key, after
* inserting the new rule. In this case, no rules are displaced by the new
* rule, even rules that cannot have any effect because the new rule matches a
* superset of their flows and has higher priority. */
struct cls_rule *
-classifier_insert(struct classifier *cls, struct cls_rule *rule)
+classifier_replace(struct classifier *cls, struct cls_rule *rule)
{
- struct cls_rule *old;
- assert((rule->wc.wildcards == 0) == (rule->table_idx == CLS_F_IDX_EXACT));
- old = (rule->wc.wildcards
- ? table_insert(&cls->tables[rule->table_idx], rule)
- : insert_exact_rule(cls, rule));
- if (!old) {
+ struct cls_rule *old_rule;
+ struct cls_subtable *subtable;
+
+ subtable = find_subtable(cls, &rule->match.mask);
+ if (!subtable) {
+ subtable = insert_subtable(cls, &rule->match.mask);
+ }
+
+ old_rule = insert_rule(cls, subtable, rule);
+ if (!old_rule) {
+ int i;
+
+ if (minimask_get_metadata_mask(&rule->match.mask) == OVS_BE64_MAX) {
+ ovs_be64 metadata = miniflow_get_metadata(&rule->match.flow);
+ rule->partition = create_partition(cls, subtable, metadata);
+ } else {
+ rule->partition = NULL;
+ }
+
+ subtable->n_rules++;
cls->n_rules++;
+
+ for (i = 0; i < cls->n_tries; i++) {
+ if (subtable->trie_plen[i]) {
+ trie_insert(&cls->tries[i], rule, subtable->trie_plen[i]);
+ }
+ }
+ } else {
+ rule->partition = old_rule->partition;
}
- return old;
+ return old_rule;
}
-/* Inserts 'rule' into 'cls'. Transfers ownership of 'rule' to 'cls'.
+/* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller
+ * must not modify or free it.
*
- * 'rule' must be an exact-match rule (rule->wc.wildcards must be 0) and 'cls'
- * must not contain any rule with an identical key. */
+ * 'cls' must not contain an identical rule (including wildcards, values of
+ * fixed fields, and priority). Use classifier_find_rule_exactly() to find
+ * such a rule. */
void
-classifier_insert_exact(struct classifier *cls, struct cls_rule *rule)
+classifier_insert(struct classifier *cls, struct cls_rule *rule)
{
- hmap_insert(&cls->exact_table, &rule->node.hmap,
- flow_hash(&rule->flow, 0));
- cls->n_rules++;
+ struct cls_rule *displaced_rule = classifier_replace(cls, rule);
+ ovs_assert(!displaced_rule);
}
-/* Removes 'rule' from 'cls'. It is caller's responsibility to free 'rule', if
- * this is desirable. */
+/* Removes 'rule' from 'cls'. It is the caller's responsibility to destroy
+ * 'rule' with cls_rule_destroy(), freeing the memory block in which 'rule'
+ * resides, etc., as necessary. */
void
classifier_remove(struct classifier *cls, struct cls_rule *rule)
{
- if (rule->wc.wildcards) {
- /* Remove 'rule' from bucket. If that empties the bucket, remove the
- * bucket from its table. */
- struct hmap *table = &cls->tables[rule->table_idx];
- struct list *rules = list_remove(&rule->node.list);
- if (list_is_empty(rules)) {
- /* This code is a little tricky. list_remove() returns the list
- * element just after the one removed. Since the list is now
- * empty, this will be the address of the 'rules' member of the
- * bucket that was just emptied, so pointer arithmetic (via
- * CONTAINER_OF) can find that bucket. */
- struct cls_bucket *bucket;
- bucket = CONTAINER_OF(rules, struct cls_bucket, rules);
- hmap_remove(table, &bucket->hmap_node);
- free(bucket);
+ struct cls_partition *partition;
+ struct cls_rule *head;
+ struct cls_subtable *subtable;
+ int i;
+
+ subtable = find_subtable(cls, &rule->match.mask);
+
+ for (i = 0; i < cls->n_tries; i++) {
+ if (subtable->trie_plen[i]) {
+ trie_remove(&cls->tries[i], rule, subtable->trie_plen[i]);
}
+ }
+
+ /* Remove rule node from indices. */
+ for (i = 0; i < subtable->n_indices; i++) {
+ hindex_remove(&subtable->indices[i], &rule->index_nodes[i]);
+ }
+
+ head = find_equal(subtable, &rule->match.flow, rule->hmap_node.hash);
+ if (head != rule) {
+ list_remove(&rule->list);
+ } else if (list_is_empty(&rule->list)) {
+ hmap_remove(&subtable->rules, &rule->hmap_node);
} else {
- /* Remove 'rule' from cls->exact_table. */
- hmap_remove(&cls->exact_table, &rule->node.hmap);
+ struct cls_rule *next = CONTAINER_OF(rule->list.next,
+ struct cls_rule, list);
+
+ list_remove(&rule->list);
+ hmap_replace(&subtable->rules, &rule->hmap_node, &next->hmap_node);
+ }
+
+ partition = rule->partition;
+ if (partition) {
+ tag_tracker_subtract(&partition->tracker, &partition->tags,
+ subtable->tag);
+ if (!partition->tags) {
+ hmap_remove(&cls->partitions, &partition->hmap_node);
+ free(partition);
+ }
}
+
+ if (--subtable->n_rules == 0) {
+ destroy_subtable(cls, subtable);
+ } else {
+ update_subtables_after_removal(cls, subtable, rule->priority);
+ }
+
cls->n_rules--;
}
+/* Prefix tree context. Valid when 'lookup_done' is true. Can skip all
+ * subtables which have more than 'match_plen' bits in their corresponding
+ * field at offset 'be32ofs'. If skipped, 'maskbits' prefix bits should be
+ * unwildcarded to quarantee datapath flow matches only packets it should. */
+struct trie_ctx {
+ const struct cls_trie *trie;
+ bool lookup_done; /* Status of the lookup. */
+ uint8_t be32ofs; /* U32 offset of the field in question. */
+ unsigned int match_plen; /* Longest prefix than could possibly match. */
+ unsigned int maskbits; /* Prefix length needed to avoid false matches. */
+};
+
+static void
+trie_ctx_init(struct trie_ctx *ctx, const struct cls_trie *trie)
+{
+ ctx->trie = trie;
+ ctx->be32ofs = trie->field->flow_be32ofs;
+ ctx->lookup_done = false;
+}
+
/* Finds and returns the highest-priority rule in 'cls' that matches 'flow'.
* Returns a null pointer if no rules in 'cls' match 'flow'. If multiple rules
* of equal priority match 'flow', returns one arbitrarily.
*
- * (When multiple rules of equal priority happen to fall into the same bucket,
- * rules added more recently take priority over rules added less recently, but
- * this is subject to change and should not be depended upon.) */
+ * If a rule is found and 'wc' is non-null, bitwise-OR's 'wc' with the
+ * set of bits that were significant in the lookup. At some point
+ * earlier, 'wc' should have been initialized (e.g., by
+ * flow_wildcards_init_catchall()). */
struct cls_rule *
-classifier_lookup(const struct classifier *cls, const flow_t *flow)
+classifier_lookup(const struct classifier *cls, const struct flow *flow,
+ struct flow_wildcards *wc)
{
- struct cls_rule *rule = classifier_lookup_exact(cls, flow);
- if (!rule) {
- rule = classifier_lookup_wild(cls, flow);
+ const struct cls_partition *partition;
+ struct cls_subtable *subtable;
+ struct cls_rule *best;
+ tag_type tags;
+ struct trie_ctx trie_ctx[CLS_MAX_TRIES];
+ int i;
+
+ /* Determine 'tags' such that, if 'subtable->tag' doesn't intersect them,
+ * then 'flow' cannot possibly match in 'subtable':
+ *
+ * - If flow->metadata maps to a given 'partition', then we can use
+ * 'tags' for 'partition->tags'.
+ *
+ * - If flow->metadata has no partition, then no rule in 'cls' has an
+ * exact-match for flow->metadata. That means that we don't need to
+ * search any subtable that includes flow->metadata in its mask.
+ *
+ * In either case, we always need to search any cls_subtables that do not
+ * include flow->metadata in its mask. One way to do that would be to
+ * check the "cls_subtable"s explicitly for that, but that would require an
+ * extra branch per subtable. Instead, we mark such a cls_subtable's
+ * 'tags' as TAG_ALL and make sure that 'tags' is never empty. This means
+ * that 'tags' always intersects such a cls_subtable's 'tags', so we don't
+ * need a special case.
+ */
+ partition = (hmap_is_empty(&cls->partitions)
+ ? NULL
+ : find_partition(cls, flow->metadata,
+ hash_metadata(flow->metadata)));
+ tags = partition ? partition->tags : TAG_ARBITRARY;
+
+ /* Initialize trie contexts for match_find_wc(). */
+ for (i = 0; i < cls->n_tries; i++) {
+ trie_ctx_init(&trie_ctx[i], &cls->tries[i]);
}
- return rule;
+ best = NULL;
+ LIST_FOR_EACH (subtable, list_node, &cls->subtables_priority) {
+ struct cls_rule *rule;
+
+ if (!tag_intersects(tags, subtable->tag)) {
+ continue;
+ }
+
+ rule = find_match_wc(subtable, flow, trie_ctx, cls->n_tries, wc);
+ if (rule) {
+ best = rule;
+ LIST_FOR_EACH_CONTINUE (subtable, list_node,
+ &cls->subtables_priority) {
+ if (subtable->max_priority <= best->priority) {
+ /* Subtables are in descending priority order,
+ * can not find anything better. */
+ return best;
+ }
+ if (!tag_intersects(tags, subtable->tag)) {
+ continue;
+ }
+
+ rule = find_match_wc(subtable, flow, trie_ctx, cls->n_tries,
+ wc);
+ if (rule && rule->priority > best->priority) {
+ best = rule;
+ }
+ }
+ break;
+ }
+ }
+
+ return best;
}
-struct cls_rule *
-classifier_lookup_exact(const struct classifier *cls, const flow_t *flow)
+/* Returns true if 'target' satisifies 'match', that is, if each bit for which
+ * 'match' specifies a particular value has the correct value in 'target'. */
+static bool
+minimatch_matches_miniflow(const struct minimatch *match,
+ const struct miniflow *target)
+{
+ const uint32_t *flowp = (const uint32_t *)match->flow.values;
+ const uint32_t *maskp = (const uint32_t *)match->mask.masks.values;
+ uint32_t target_u32;
+
+ MINIFLOW_FOR_EACH_IN_MAP(target_u32, target, match->mask.masks.map) {
+ if ((*flowp++ ^ target_u32) & *maskp++) {
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static inline struct cls_rule *
+find_match_miniflow(const struct cls_subtable *subtable,
+ const struct miniflow *flow,
+ uint32_t hash)
{
- return (!hmap_is_empty(&cls->exact_table)
- ? search_exact_table(cls, flow_hash(flow, 0), flow)
- : NULL);
+ struct cls_rule *rule;
+
+ HMAP_FOR_EACH_WITH_HASH (rule, hmap_node, hash, &subtable->rules) {
+ if (minimatch_matches_miniflow(&rule->match, flow)) {
+ return rule;
+ }
+ }
+
+ return NULL;
}
-struct cls_rule *
-classifier_lookup_wild(const struct classifier *cls, const flow_t *flow)
+/* Finds and returns the highest-priority rule in 'cls' that matches
+ * 'miniflow'. Returns a null pointer if no rules in 'cls' match 'flow'.
+ * If multiple rules of equal priority match 'flow', returns one arbitrarily.
+ *
+ * This function is optimized for the userspace datapath, which only ever has
+ * one priority value for it's flows!
+ */
+struct cls_rule *classifier_lookup_miniflow_first(const struct classifier *cls,
+ const struct miniflow *flow)
{
- struct cls_rule *best = NULL;
- if (cls->n_rules > hmap_count(&cls->exact_table)) {
- struct cls_rule target;
- int i;
+ struct cls_subtable *subtable;
- cls_rule_from_flow(&target, flow, 0, 0);
- for (i = 0; i < CLS_N_FIELDS; i++) {
- struct cls_rule *rule = search_table(&cls->tables[i], i, &target);
- if (rule && (!best || rule->priority > best->priority)) {
- best = rule;
- }
+ LIST_FOR_EACH (subtable, list_node, &cls->subtables_priority) {
+ struct cls_rule *rule;
+
+ rule = find_match_miniflow(subtable, flow,
+ miniflow_hash_in_minimask(flow,
+ &subtable->mask,
+ 0));
+ if (rule) {
+ return rule;
}
}
- return best;
+
+ return NULL;
}
+/* Finds and returns a rule in 'cls' with exactly the same priority and
+ * matching criteria as 'target'. Returns a null pointer if 'cls' doesn't
+ * contain an exact match. */
struct cls_rule *
classifier_find_rule_exactly(const struct classifier *cls,
- const flow_t *target, uint32_t wildcards,
- unsigned int priority)
+ const struct cls_rule *target)
{
- struct cls_bucket *bucket;
- int table_idx;
- uint32_t hash;
-
- if (!wildcards) {
- /* Ignores 'priority'. */
- return search_exact_table(cls, flow_hash(target, 0), target);
- }
-
- assert(wildcards == (wildcards & OFPFW_ALL));
- table_idx = table_idx_from_wildcards(wildcards);
- hash = hash_fields(target, table_idx);
- HMAP_FOR_EACH_WITH_HASH (bucket, struct cls_bucket, hmap_node, hash,
- &cls->tables[table_idx]) {
- if (equal_fields(&bucket->fixed, target, table_idx)) {
- struct cls_rule *pos;
- LIST_FOR_EACH (pos, struct cls_rule, node.list, &bucket->rules) {
- if (pos->priority < priority) {
- return NULL;
- } else if (pos->priority == priority &&
- pos->wc.wildcards == wildcards &&
- flow_equal(target, &pos->flow)) {
- return pos;
- }
- }
+ struct cls_rule *head, *rule;
+ struct cls_subtable *subtable;
+
+ subtable = find_subtable(cls, &target->match.mask);
+ if (!subtable) {
+ return NULL;
+ }
+
+ /* Skip if there is no hope. */
+ if (target->priority > subtable->max_priority) {
+ return NULL;
+ }
+
+ head = find_equal(subtable, &target->match.flow,
+ miniflow_hash_in_minimask(&target->match.flow,
+ &target->match.mask, 0));
+ FOR_EACH_RULE_IN_LIST (rule, head) {
+ if (target->priority >= rule->priority) {
+ return target->priority == rule->priority ? rule : NULL;
}
}
return NULL;
}
-/* Ignores target->priority.
- *
- * 'callback' is allowed to delete the rule that is passed as its argument, but
- * it must not delete (or move) any other rules in 'cls' that are in the same
- * table as the argument rule. Two rules are in the same table if their
- * cls_rule structs have the same table_idx; as a special case, a rule with
- * wildcards and an exact-match rule will never be in the same table. */
-void
-classifier_for_each_match(const struct classifier *cls,
- const struct cls_rule *target,
- int include, cls_cb_func *callback, void *aux)
-{
- if (include & CLS_INC_WILD) {
- const struct hmap *table;
-
- for (table = &cls->tables[0]; table < &cls->tables[CLS_N_FIELDS];
- table++) {
- struct cls_bucket *bucket, *next_bucket;
-
- HMAP_FOR_EACH_SAFE (bucket, next_bucket,
- struct cls_bucket, hmap_node, table) {
- /* XXX there is a bit of room for optimization here based on
- * rejecting entire buckets on their fixed fields, but it will
- * only be worthwhile for big buckets (which we hope we won't
- * get anyway, but...) */
- struct cls_rule *prev_rule, *rule;
-
- /* We can't just use LIST_FOR_EACH_SAFE here because, if the
- * callback deletes the last rule in the bucket, then the
- * bucket itself will be destroyed. The bucket contains the
- * list head so that's a use-after-free error. */
- prev_rule = NULL;
- LIST_FOR_EACH (rule, struct cls_rule, node.list,
- &bucket->rules) {
- if (rules_match_1wild(rule, target, 0)) {
- if (prev_rule) {
- callback(prev_rule, aux);
- }
- prev_rule = rule;
- }
+/* Finds and returns a rule in 'cls' with priority 'priority' and exactly the
+ * same matching criteria as 'target'. Returns a null pointer if 'cls' doesn't
+ * contain an exact match. */
+struct cls_rule *
+classifier_find_match_exactly(const struct classifier *cls,
+ const struct match *target,
+ unsigned int priority)
+{
+ struct cls_rule *retval;
+ struct cls_rule cr;
+
+ cls_rule_init(&cr, target, priority);
+ retval = classifier_find_rule_exactly(cls, &cr);
+ cls_rule_destroy(&cr);
+
+ return retval;
+}
+
+/* Checks if 'target' would overlap any other rule in 'cls'. Two rules are
+ * considered to overlap if both rules have the same priority and a packet
+ * could match both. */
+bool
+classifier_rule_overlaps(const struct classifier *cls,
+ const struct cls_rule *target)
+{
+ struct cls_subtable *subtable;
+
+ /* Iterate subtables in the descending max priority order. */
+ LIST_FOR_EACH (subtable, list_node, &cls->subtables_priority) {
+ uint32_t storage[FLOW_U32S];
+ struct minimask mask;
+ struct cls_rule *head;
+
+ if (target->priority > subtable->max_priority) {
+ break; /* Can skip this and the rest of the subtables. */
+ }
+
+ minimask_combine(&mask, &target->match.mask, &subtable->mask, storage);
+ HMAP_FOR_EACH (head, hmap_node, &subtable->rules) {
+ struct cls_rule *rule;
+
+ FOR_EACH_RULE_IN_LIST (rule, head) {
+ if (rule->priority < target->priority) {
+ break; /* Rules in descending priority order. */
}
- if (prev_rule) {
- callback(prev_rule, aux);
+ if (rule->priority == target->priority
+ && miniflow_equal_in_minimask(&target->match.flow,
+ &rule->match.flow, &mask)) {
+ return true;
}
}
}
}
- if (include & CLS_INC_EXACT) {
- if (target->wc.wildcards) {
- struct cls_rule *rule, *next_rule;
+ return false;
+}
- HMAP_FOR_EACH_SAFE (rule, next_rule, struct cls_rule, node.hmap,
- &cls->exact_table) {
- if (rules_match_1wild(rule, target, 0)) {
- callback(rule, aux);
- }
- }
- } else {
- /* Optimization: there can be at most one match in the exact
- * table. */
- size_t hash = flow_hash(&target->flow, 0);
- struct cls_rule *rule = search_exact_table(cls, hash,
- &target->flow);
- if (rule) {
- callback(rule, aux);
+/* Returns true if 'rule' exactly matches 'criteria' or if 'rule' is more
+ * specific than 'criteria'. That is, 'rule' matches 'criteria' and this
+ * function returns true if, for every field:
+ *
+ * - 'criteria' and 'rule' specify the same (non-wildcarded) value for the
+ * field, or
+ *
+ * - 'criteria' wildcards the field,
+ *
+ * Conversely, 'rule' does not match 'criteria' and this function returns false
+ * if, for at least one field:
+ *
+ * - 'criteria' and 'rule' specify different values for the field, or
+ *
+ * - 'criteria' specifies a value for the field but 'rule' wildcards it.
+ *
+ * Equivalently, the truth table for whether a field matches is:
+ *
+ * rule
+ *
+ * c wildcard exact
+ * r +---------+---------+
+ * i wild | yes | yes |
+ * t card | | |
+ * e +---------+---------+
+ * r exact | no |if values|
+ * i | |are equal|
+ * a +---------+---------+
+ *
+ * This is the matching rule used by OpenFlow 1.0 non-strict OFPT_FLOW_MOD
+ * commands and by OpenFlow 1.0 aggregate and flow stats.
+ *
+ * Ignores rule->priority. */
+bool
+cls_rule_is_loose_match(const struct cls_rule *rule,
+ const struct minimatch *criteria)
+{
+ return (!minimask_has_extra(&rule->match.mask, &criteria->mask)
+ && miniflow_equal_in_minimask(&rule->match.flow, &criteria->flow,
+ &criteria->mask));
+}
+\f
+/* Iteration. */
+
+static bool
+rule_matches(const struct cls_rule *rule, const struct cls_rule *target)
+{
+ return (!target
+ || miniflow_equal_in_minimask(&rule->match.flow,
+ &target->match.flow,
+ &target->match.mask));
+}
+
+static struct cls_rule *
+search_subtable(const struct cls_subtable *subtable,
+ const struct cls_rule *target)
+{
+ if (!target || !minimask_has_extra(&subtable->mask, &target->match.mask)) {
+ struct cls_rule *rule;
+
+ HMAP_FOR_EACH (rule, hmap_node, &subtable->rules) {
+ if (rule_matches(rule, target)) {
+ return rule;
}
}
}
+ return NULL;
}
-/* 'callback' is allowed to delete the rule that is passed as its argument, but
- * it must not delete (or move) any other rules in 'cls' that are in the same
- * table as the argument rule. Two rules are in the same table if their
- * cls_rule structs have the same table_idx; as a special case, a rule with
- * wildcards and an exact-match rule will never be in the same table. */
+/* Initializes 'cursor' for iterating through rules in 'cls':
+ *
+ * - If 'target' is null, the cursor will visit every rule in 'cls'.
+ *
+ * - If 'target' is nonnull, the cursor will visit each 'rule' in 'cls'
+ * such that cls_rule_is_loose_match(rule, target) returns true.
+ *
+ * Ignores target->priority. */
void
-classifier_for_each(const struct classifier *cls, int include,
- void (*callback)(struct cls_rule *, void *aux),
- void *aux)
-{
- if (include & CLS_INC_WILD) {
- const struct hmap *tbl;
-
- for (tbl = &cls->tables[0]; tbl < &cls->tables[CLS_N_FIELDS]; tbl++) {
- struct cls_bucket *bucket, *next_bucket;
-
- HMAP_FOR_EACH_SAFE (bucket, next_bucket,
- struct cls_bucket, hmap_node, tbl) {
- struct cls_rule *prev_rule, *rule;
-
- /* We can't just use LIST_FOR_EACH_SAFE here because, if the
- * callback deletes the last rule in the bucket, then the
- * bucket itself will be destroyed. The bucket contains the
- * list head so that's a use-after-free error. */
- prev_rule = NULL;
- LIST_FOR_EACH (rule, struct cls_rule, node.list,
- &bucket->rules) {
- if (prev_rule) {
- callback(prev_rule, aux);
- }
- prev_rule = rule;
- }
- if (prev_rule) {
- callback(prev_rule, aux);
- }
- }
+cls_cursor_init(struct cls_cursor *cursor, const struct classifier *cls,
+ const struct cls_rule *target)
+{
+ cursor->cls = cls;
+ cursor->target = target && !cls_rule_is_catchall(target) ? target : NULL;
+}
+
+/* Returns the first matching cls_rule in 'cursor''s iteration, or a null
+ * pointer if there are no matches. */
+struct cls_rule *
+cls_cursor_first(struct cls_cursor *cursor)
+{
+ struct cls_subtable *subtable;
+
+ HMAP_FOR_EACH (subtable, hmap_node, &cursor->cls->subtables) {
+ struct cls_rule *rule = search_subtable(subtable, cursor->target);
+ if (rule) {
+ cursor->subtable = subtable;
+ return rule;
}
}
- if (include & CLS_INC_EXACT) {
- struct cls_rule *rule, *next_rule;
+ return NULL;
+}
+
+/* Returns the next matching cls_rule in 'cursor''s iteration, or a null
+ * pointer if there are no more matches. */
+struct cls_rule *
+cls_cursor_next(struct cls_cursor *cursor, const struct cls_rule *rule_)
+{
+ struct cls_rule *rule = CONST_CAST(struct cls_rule *, rule_);
+ const struct cls_subtable *subtable;
+ struct cls_rule *next;
+
+ next = next_rule_in_list__(rule);
+ if (next->priority < rule->priority) {
+ return next;
+ }
+
+ /* 'next' is the head of the list, that is, the rule that is included in
+ * the subtable's hmap. (This is important when the classifier contains
+ * rules that differ only in priority.) */
+ rule = next;
+ HMAP_FOR_EACH_CONTINUE (rule, hmap_node, &cursor->subtable->rules) {
+ if (rule_matches(rule, cursor->target)) {
+ return rule;
+ }
+ }
- HMAP_FOR_EACH_SAFE (rule, next_rule,
- struct cls_rule, node.hmap, &cls->exact_table) {
- callback(rule, aux);
+ subtable = cursor->subtable;
+ HMAP_FOR_EACH_CONTINUE (subtable, hmap_node, &cursor->cls->subtables) {
+ rule = search_subtable(subtable, cursor->target);
+ if (rule) {
+ cursor->subtable = subtable;
+ return rule;
}
}
+
+ return NULL;
}
\f
-static struct cls_bucket *create_bucket(struct hmap *, size_t hash,
- const flow_t *fixed);
-static struct cls_rule *bucket_insert(struct cls_bucket *, struct cls_rule *);
+static struct cls_subtable *
+find_subtable(const struct classifier *cls, const struct minimask *mask)
+{
+ struct cls_subtable *subtable;
-static inline bool equal_bytes(const void *, const void *, size_t n);
+ HMAP_FOR_EACH_IN_BUCKET (subtable, hmap_node, minimask_hash(mask, 0),
+ &cls->subtables) {
+ if (minimask_equal(mask, &subtable->mask)) {
+ return subtable;
+ }
+ }
+ return NULL;
+}
-/* Returns a hash computed across the fields in 'flow' whose field indexes
- * (CLS_F_IDX_*) are less than 'table_idx'. (If 'table_idx' is
- * CLS_F_IDX_EXACT, hashes all the fields in 'flow'). */
-static uint32_t
-hash_fields(const flow_t *flow, int table_idx)
+static struct cls_subtable *
+insert_subtable(struct classifier *cls, const struct minimask *mask)
{
- /* I just know I'm going to hell for writing code this way.
- *
- * GCC generates pretty good code here, with only a single taken
- * conditional jump per execution. Now the question is, would we be better
- * off marking this function ALWAYS_INLINE and writing a wrapper that
- * switches on the value of 'table_idx' to get rid of all the conditional
- * jumps entirely (except for one in the wrapper)? Honestly I really,
- * really hope that it doesn't matter in practice.
- *
- * We could do better by calculating hashes incrementally, instead of
- * starting over from the top each time. But that would be even uglier. */
- uint32_t a, b, c;
- uint32_t tmp[3];
- size_t n;
-
- a = b = c = 0xdeadbeef + table_idx;
- n = 0;
-
-#define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
- if (table_idx == CLS_F_IDX_##NAME) { \
- /* Done. */ \
- memset((uint8_t *) tmp + n, 0, sizeof tmp - n); \
- goto finish; \
- } else { \
- const size_t size = sizeof flow->MEMBER; \
- const uint8_t *p1 = (const uint8_t *) &flow->MEMBER; \
- const size_t p1_size = MIN(sizeof tmp - n, size); \
- const uint8_t *p2 = p1 + p1_size; \
- const size_t p2_size = size - p1_size; \
- \
- /* Append to 'tmp' as much data as will fit. */ \
- memcpy((uint8_t *) tmp + n, p1, p1_size); \
- n += p1_size; \
- \
- /* If 'tmp' is full, mix. */ \
- if (n == sizeof tmp) { \
- a += tmp[0]; \
- b += tmp[1]; \
- c += tmp[2]; \
- HASH_MIX(a, b, c); \
- n = 0; \
- } \
- \
- /* Append to 'tmp' any data that didn't fit. */ \
- memcpy(tmp, p2, p2_size); \
- n += p2_size; \
- }
- CLS_FIELDS
-#undef CLS_FIELD
-
-finish:
- a += tmp[0];
- b += tmp[1];
- c += tmp[2];
- HASH_FINAL(a, b, c);
- return c;
-}
-
-/* Compares the fields in 'a' and 'b' whose field indexes (CLS_F_IDX_*) are
- * less than 'table_idx'. (If 'table_idx' is CLS_F_IDX_EXACT, compares all the
- * fields in 'a' and 'b').
- *
- * Returns true if all the compared fields are equal, false otherwise. */
-static bool
-equal_fields(const flow_t *a, const flow_t *b, int table_idx)
+ uint32_t hash = minimask_hash(mask, 0);
+ struct cls_subtable *subtable;
+ int i, index = 0;
+ struct flow_wildcards old, new;
+ uint8_t prev;
+
+ subtable = xzalloc(sizeof *subtable);
+ hmap_init(&subtable->rules);
+ minimask_clone(&subtable->mask, mask);
+
+ /* Init indices for segmented lookup, if any. */
+ flow_wildcards_init_catchall(&new);
+ old = new;
+ prev = 0;
+ for (i = 0; i < cls->n_flow_segments; i++) {
+ flow_wildcards_fold_minimask_range(&new, mask, prev,
+ cls->flow_segments[i]);
+ /* Add an index if it adds mask bits. */
+ if (!flow_wildcards_equal(&new, &old)) {
+ hindex_init(&subtable->indices[index]);
+ subtable->index_ofs[index] = cls->flow_segments[i];
+ index++;
+ old = new;
+ }
+ prev = cls->flow_segments[i];
+ }
+ /* Check if the rest of the subtable's mask adds any bits,
+ * and remove the last index if it doesn't. */
+ if (index > 0) {
+ flow_wildcards_fold_minimask_range(&new, mask, prev, FLOW_U32S);
+ if (flow_wildcards_equal(&new, &old)) {
+ --index;
+ subtable->index_ofs[index] = 0;
+ hindex_destroy(&subtable->indices[index]);
+ }
+ }
+ subtable->n_indices = index;
+
+ hmap_insert(&cls->subtables, &subtable->hmap_node, hash);
+ list_push_back(&cls->subtables_priority, &subtable->list_node);
+ subtable->tag = (minimask_get_metadata_mask(mask) == OVS_BE64_MAX
+ ? tag_create_deterministic(hash)
+ : TAG_ALL);
+
+ for (i = 0; i < cls->n_tries; i++) {
+ subtable->trie_plen[i] = minimask_get_prefix_len(mask,
+ cls->tries[i].field);
+ }
+
+ return subtable;
+}
+
+static void
+destroy_subtable(struct classifier *cls, struct cls_subtable *subtable)
{
- /* XXX The generated code could be better here. */
-#define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
- if (table_idx == CLS_F_IDX_##NAME) { \
- return true; \
- } else if (!equal_bytes(&a->MEMBER, &b->MEMBER, sizeof a->MEMBER)) { \
- return false; \
+ int i;
+
+ for (i = 0; i < subtable->n_indices; i++) {
+ hindex_destroy(&subtable->indices[i]);
}
- CLS_FIELDS
-#undef CLS_FIELD
+ minimask_destroy(&subtable->mask);
+ hmap_remove(&cls->subtables, &subtable->hmap_node);
+ hmap_destroy(&subtable->rules);
+ list_remove(&subtable->list_node);
+ free(subtable);
+}
- return true;
+/* This function performs the following updates for 'subtable' in 'cls'
+ * following the addition of a new rule with priority 'new_priority' to
+ * 'subtable':
+ *
+ * - Update 'subtable->max_priority' and 'subtable->max_count' if necessary.
+ *
+ * - Update 'subtable''s position in 'cls->subtables_priority' if necessary.
+ *
+ * This function should only be called after adding a new rule, not after
+ * replacing a rule by an identical one or modifying a rule in-place. */
+static void
+update_subtables_after_insertion(struct classifier *cls,
+ struct cls_subtable *subtable,
+ unsigned int new_priority)
+{
+ if (new_priority == subtable->max_priority) {
+ ++subtable->max_count;
+ } else if (new_priority > subtable->max_priority) {
+ struct cls_subtable *iter;
+
+ subtable->max_priority = new_priority;
+ subtable->max_count = 1;
+
+ /* Possibly move 'subtable' earlier in the priority list. If we break
+ * out of the loop, then 'subtable' should be moved just after that
+ * 'iter'. If the loop terminates normally, then 'iter' will be the
+ * list head and we'll move subtable just after that (e.g. to the front
+ * of the list). */
+ iter = subtable;
+ LIST_FOR_EACH_REVERSE_CONTINUE (iter, list_node,
+ &cls->subtables_priority) {
+ if (iter->max_priority >= subtable->max_priority) {
+ break;
+ }
+ }
+
+ /* Move 'subtable' just after 'iter' (unless it's already there). */
+ if (iter->list_node.next != &subtable->list_node) {
+ list_splice(iter->list_node.next,
+ &subtable->list_node, subtable->list_node.next);
+ }
+ }
}
-static int
-table_idx_from_wildcards(uint32_t wildcards)
+/* This function performs the following updates for 'subtable' in 'cls'
+ * following the deletion of a rule with priority 'del_priority' from
+ * 'subtable':
+ *
+ * - Update 'subtable->max_priority' and 'subtable->max_count' if necessary.
+ *
+ * - Update 'subtable''s position in 'cls->subtables_priority' if necessary.
+ *
+ * This function should only be called after removing a rule, not after
+ * replacing a rule by an identical one or modifying a rule in-place. */
+static void
+update_subtables_after_removal(struct classifier *cls,
+ struct cls_subtable *subtable,
+ unsigned int del_priority)
{
- if (!wildcards) {
- return CLS_F_IDX_EXACT;
+ struct cls_subtable *iter;
+
+ if (del_priority == subtable->max_priority && --subtable->max_count == 0) {
+ struct cls_rule *head;
+
+ subtable->max_priority = 0;
+ HMAP_FOR_EACH (head, hmap_node, &subtable->rules) {
+ if (head->priority > subtable->max_priority) {
+ subtable->max_priority = head->priority;
+ subtable->max_count = 1;
+ } else if (head->priority == subtable->max_priority) {
+ ++subtable->max_count;
+ }
+ }
+
+ /* Possibly move 'subtable' later in the priority list. If we break
+ * out of the loop, then 'subtable' should be moved just before that
+ * 'iter'. If the loop terminates normally, then 'iter' will be the
+ * list head and we'll move subtable just before that (e.g. to the back
+ * of the list). */
+ iter = subtable;
+ LIST_FOR_EACH_CONTINUE (iter, list_node, &cls->subtables_priority) {
+ if (iter->max_priority <= subtable->max_priority) {
+ break;
+ }
+ }
+
+ /* Move 'subtable' just before 'iter' (unless it's already there). */
+ if (iter->list_node.prev != &subtable->list_node) {
+ list_splice(&iter->list_node,
+ &subtable->list_node, subtable->list_node.next);
+ }
}
-#define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
- if (wildcards & WILDCARDS) { \
- return CLS_F_IDX_##NAME; \
+}
+
+struct range {
+ uint8_t start;
+ uint8_t end;
+};
+
+/* Return 'true' if can skip rest of the subtable based on the prefix trie
+ * lookup results. */
+static inline bool
+check_tries(struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries,
+ const unsigned int field_plen[CLS_MAX_TRIES],
+ const struct range ofs, const struct flow *flow,
+ struct flow_wildcards *wc)
+{
+ int j;
+
+ /* Check if we could avoid fully unwildcarding the next level of
+ * fields using the prefix tries. The trie checks are done only as
+ * needed to avoid folding in additional bits to the wildcards mask. */
+ for (j = 0; j < n_tries; j++) {
+ /* Is the trie field relevant for this subtable? */
+ if (field_plen[j]) {
+ struct trie_ctx *ctx = &trie_ctx[j];
+ uint8_t be32ofs = ctx->be32ofs;
+
+ /* Is the trie field within the current range of fields? */
+ if (be32ofs >= ofs.start && be32ofs < ofs.end) {
+ /* On-demand trie lookup. */
+ if (!ctx->lookup_done) {
+ ctx->match_plen = trie_lookup(ctx->trie, flow,
+ &ctx->maskbits);
+ ctx->lookup_done = true;
+ }
+ /* Possible to skip the rest of the subtable if subtable's
+ * prefix on the field is longer than what is known to match
+ * based on the trie lookup. */
+ if (field_plen[j] > ctx->match_plen) {
+ /* RFC: We want the trie lookup to never result in
+ * unwildcarding any bits that would not be unwildcarded
+ * otherwise. Since the trie is shared by the whole
+ * classifier, it is possible that the 'maskbits' contain
+ * bits that are irrelevant for the partition of the
+ * classifier relevant for the current flow. */
+
+ /* Can skip if the field is already unwildcarded. */
+ if (mask_prefix_bits_set(wc, be32ofs, ctx->maskbits)) {
+ return true;
+ }
+ /* Check that the trie result will not unwildcard more bits
+ * than this stage will. */
+ if (ctx->maskbits <= field_plen[j]) {
+ /* Unwildcard the bits and skip the rest. */
+ mask_set_prefix_bits(wc, be32ofs, ctx->maskbits);
+ /* Note: Prerequisite already unwildcarded, as the only
+ * prerequisite of the supported trie lookup fields is
+ * the ethertype, which is currently always
+ * unwildcarded.
+ */
+ return true;
+ }
+ }
+ }
+ }
}
- CLS_FIELDS
-#undef CLS_FIELD
- NOT_REACHED();
+ return false;
}
-/* Inserts 'rule' into 'table'. Returns the rule, if any, that was displaced
- * in favor of 'rule'. */
-static struct cls_rule *
-table_insert(struct hmap *table, struct cls_rule *rule)
+static inline struct cls_rule *
+find_match(const struct cls_subtable *subtable, const struct flow *flow,
+ uint32_t hash)
{
- struct cls_bucket *bucket;
- size_t hash;
+ struct cls_rule *rule;
- hash = hash_fields(&rule->flow, rule->table_idx);
- bucket = find_bucket(table, hash, rule);
- if (!bucket) {
- bucket = create_bucket(table, hash, &rule->flow);
+ HMAP_FOR_EACH_WITH_HASH (rule, hmap_node, hash, &subtable->rules) {
+ if (minimatch_matches_flow(&rule->match, flow)) {
+ return rule;
+ }
}
- return bucket_insert(bucket, rule);
+ return NULL;
}
-/* Inserts 'rule' into 'bucket', given that 'field' is the first wildcarded
- * field in 'rule'.
- *
- * Returns the rule, if any, that was displaced in favor of 'rule'. */
static struct cls_rule *
-bucket_insert(struct cls_bucket *bucket, struct cls_rule *rule)
-{
- struct cls_rule *pos;
- LIST_FOR_EACH (pos, struct cls_rule, node.list, &bucket->rules) {
- if (pos->priority <= rule->priority) {
- if (pos->priority == rule->priority
- && pos->wc.wildcards == rule->wc.wildcards
- && rules_match_1wild(pos, rule, rule->table_idx))
- {
- list_replace(&rule->node.list, &pos->node.list);
- return pos;
+find_match_wc(const struct cls_subtable *subtable, const struct flow *flow,
+ struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries,
+ struct flow_wildcards *wc)
+{
+ uint32_t basis = 0, hash;
+ struct cls_rule *rule = NULL;
+ int i;
+ struct range ofs;
+
+ if (!wc) {
+ return find_match(subtable, flow,
+ flow_hash_in_minimask(flow, &subtable->mask, 0));
+ }
+
+ ofs.start = 0;
+ /* Try to finish early by checking fields in segments. */
+ for (i = 0; i < subtable->n_indices; i++) {
+ struct hindex_node *inode;
+ ofs.end = subtable->index_ofs[i];
+
+ if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow,
+ wc)) {
+ goto range_out;
+ }
+ hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
+ ofs.end, &basis);
+ ofs.start = ofs.end;
+ inode = hindex_node_with_hash(&subtable->indices[i], hash);
+ if (!inode) {
+ /* No match, can stop immediately, but must fold in the mask
+ * covered so far. */
+ goto range_out;
+ }
+
+ /* If we have narrowed down to a single rule already, check whether
+ * that rule matches. If it does match, then we're done. If it does
+ * not match, then we know that we will never get a match, but we do
+ * not yet know how many wildcards we need to fold into 'wc' so we
+ * continue iterating through indices to find that out. (We won't
+ * waste time calling minimatch_matches_flow() again because we've set
+ * 'rule' nonnull.)
+ *
+ * This check shows a measurable benefit with non-trivial flow tables.
+ *
+ * (Rare) hash collisions may cause us to miss the opportunity for this
+ * optimization. */
+ if (!inode->s && !rule) {
+ ASSIGN_CONTAINER(rule, inode - i, index_nodes);
+ if (minimatch_matches_flow(&rule->match, flow)) {
+ goto out;
}
- break;
}
}
- list_insert(&pos->node.list, &rule->node.list);
+ ofs.end = FLOW_U32S;
+ /* Trie check for the final range. */
+ if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow, wc)) {
+ goto range_out;
+ }
+ if (!rule) {
+ /* Multiple potential matches exist, look for one. */
+ hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
+ ofs.end, &basis);
+ rule = find_match(subtable, flow, hash);
+ } else {
+ /* We already narrowed the matching candidates down to just 'rule',
+ * but it didn't match. */
+ rule = NULL;
+ }
+ out:
+ /* Must unwildcard all the fields, as they were looked at. */
+ flow_wildcards_fold_minimask(wc, &subtable->mask);
+ return rule;
+
+ range_out:
+ /* Must unwildcard the fields looked up so far, if any. */
+ if (ofs.start) {
+ flow_wildcards_fold_minimask_range(wc, &subtable->mask, 0, ofs.start);
+ }
return NULL;
}
static struct cls_rule *
-insert_exact_rule(struct classifier *cls, struct cls_rule *rule)
+find_equal(struct cls_subtable *subtable, const struct miniflow *flow,
+ uint32_t hash)
{
- struct cls_rule *old_rule;
- size_t hash;
+ struct cls_rule *head;
- hash = flow_hash(&rule->flow, 0);
- old_rule = search_exact_table(cls, hash, &rule->flow);
- if (old_rule) {
- hmap_remove(&cls->exact_table, &old_rule->node.hmap);
+ HMAP_FOR_EACH_WITH_HASH (head, hmap_node, hash, &subtable->rules) {
+ if (miniflow_equal(&head->match.flow, flow)) {
+ return head;
+ }
}
- hmap_insert(&cls->exact_table, &rule->node.hmap, hash);
- return old_rule;
+ return NULL;
}
-/* Returns the bucket in 'table' that has the given 'hash' and the same fields
- * as 'rule->flow' (up to 'rule->table_idx'), or a null pointer if no bucket
- * matches. */
-static struct cls_bucket *
-find_bucket(struct hmap *table, size_t hash, const struct cls_rule *rule)
+static struct cls_rule *
+insert_rule(struct classifier *cls, struct cls_subtable *subtable,
+ struct cls_rule *new)
{
- struct cls_bucket *bucket;
- HMAP_FOR_EACH_WITH_HASH (bucket, struct cls_bucket, hmap_node, hash,
- table) {
- if (equal_fields(&bucket->fixed, &rule->flow, rule->table_idx)) {
- return bucket;
+ struct cls_rule *head;
+ struct cls_rule *old = NULL;
+ int i;
+ uint32_t basis = 0, hash;
+ uint8_t prev_be32ofs = 0;
+
+ /* Add new node to segment indices. */
+ for (i = 0; i < subtable->n_indices; i++) {
+ hash = minimatch_hash_range(&new->match, prev_be32ofs,
+ subtable->index_ofs[i], &basis);
+ hindex_insert(&subtable->indices[i], &new->index_nodes[i], hash);
+ prev_be32ofs = subtable->index_ofs[i];
+ }
+ hash = minimatch_hash_range(&new->match, prev_be32ofs, FLOW_U32S, &basis);
+ head = find_equal(subtable, &new->match.flow, hash);
+ if (!head) {
+ hmap_insert(&subtable->rules, &new->hmap_node, hash);
+ list_init(&new->list);
+ goto out;
+ } else {
+ /* Scan the list for the insertion point that will keep the list in
+ * order of decreasing priority. */
+ struct cls_rule *rule;
+
+ new->hmap_node.hash = hash; /* Otherwise done by hmap_insert. */
+
+ FOR_EACH_RULE_IN_LIST (rule, head) {
+ if (new->priority >= rule->priority) {
+ if (rule == head) {
+ /* 'new' is the new highest-priority flow in the list. */
+ hmap_replace(&subtable->rules,
+ &rule->hmap_node, &new->hmap_node);
+ }
+
+ if (new->priority == rule->priority) {
+ list_replace(&new->list, &rule->list);
+ old = rule;
+ goto out;
+ } else {
+ list_insert(&rule->list, &new->list);
+ goto out;
+ }
+ }
}
+
+ /* Insert 'new' at the end of the list. */
+ list_push_back(&head->list, &new->list);
}
- return NULL;
+
+ out:
+ if (!old) {
+ update_subtables_after_insertion(cls, subtable, new->priority);
+ } else {
+ /* Remove old node from indices. */
+ for (i = 0; i < subtable->n_indices; i++) {
+ hindex_remove(&subtable->indices[i], &old->index_nodes[i]);
+ }
+ }
+ return old;
}
-/* Creates a bucket and inserts it in 'table' with the given 'hash' and 'fixed'
- * values. Returns the new bucket. */
-static struct cls_bucket *
-create_bucket(struct hmap *table, size_t hash, const flow_t *fixed)
+static struct cls_rule *
+next_rule_in_list__(struct cls_rule *rule)
{
- struct cls_bucket *bucket = xmalloc(sizeof *bucket);
- list_init(&bucket->rules);
- bucket->fixed = *fixed;
- hmap_insert(table, &bucket->hmap_node, hash);
- return bucket;
+ struct cls_rule *next = OBJECT_CONTAINING(rule->list.next, next, list);
+ return next;
}
-/* Returns true if the 'n' bytes in 'a' and 'b' are equal, false otherwise. */
-static inline bool ALWAYS_INLINE
-equal_bytes(const void *a, const void *b, size_t n)
+static struct cls_rule *
+next_rule_in_list(struct cls_rule *rule)
{
-#ifdef __i386__
- /* For some reason GCC generates stupid code for memcmp() of small
- * constant integer lengths. Help it out.
- *
- * This function is always inlined, and it is always called with 'n' as a
- * compile-time constant, so the switch statement gets optimized out and
- * this whole function just expands to an instruction or two. */
- switch (n) {
- case 1:
- return *(uint8_t *) a == *(uint8_t *) b;
-
- case 2:
- return *(uint16_t *) a == *(uint16_t *) b;
-
- case 4:
- return *(uint32_t *) a == *(uint32_t *) b;
-
- case 6:
- return (*(uint32_t *) a == *(uint32_t *) b
- && ((uint16_t *) a)[2] == ((uint16_t *) b)[2]);
-
- default:
- abort();
- }
-#else
- /* I hope GCC is smarter on your platform. */
- return !memcmp(a, b, n);
-#endif
-}
-
-/* Returns the 32-bit unsigned integer at 'p'. */
-static inline uint32_t
-read_uint32(const void *p)
-{
- /* GCC optimizes this into a single machine instruction on x86. */
- uint32_t x;
- memcpy(&x, p, sizeof x);
- return x;
-}
-
-/* Compares the specified field in 'a' and 'b'. Returns true if the fields are
- * equal, or if the ofp_match wildcard bits in 'wildcards' are set such that
- * non-equal values may be ignored. 'nw_src_mask' and 'nw_dst_mask' must be
- * those that would be set for 'wildcards' by cls_rule_set_masks().
- *
- * The compared field is the one with wildcard bit or bits 'field_wc', offset
- * 'rule_ofs' within cls_rule's "fields" member, and length 'len', in bytes. */
-static inline bool ALWAYS_INLINE
-field_matches(const flow_t *a_, const flow_t *b_,
- uint32_t wildcards, uint32_t nw_src_mask, uint32_t nw_dst_mask,
- uint32_t field_wc, int ofs, int len)
-{
- /* This function is always inlined, and it is always called with 'field_wc'
- * as a compile-time constant, so the "if" conditionals here generate no
- * code. */
- const void *a = (const uint8_t *) a_ + ofs;
- const void *b = (const uint8_t *) b_ + ofs;
- if (!(field_wc & (field_wc - 1))) {
- /* Handle all the single-bit wildcard cases. */
- return wildcards & field_wc || equal_bytes(a, b, len);
- } else if (field_wc == OFPFW_NW_SRC_MASK ||
- field_wc == OFPFW_NW_DST_MASK) {
- uint32_t a_ip = read_uint32(a);
- uint32_t b_ip = read_uint32(b);
- uint32_t mask = (field_wc == OFPFW_NW_SRC_MASK
- ? nw_src_mask : nw_dst_mask);
- return ((a_ip ^ b_ip) & mask) == 0;
- } else {
- abort();
+ struct cls_rule *next = next_rule_in_list__(rule);
+ return next->priority < rule->priority ? next : NULL;
+}
+\f
+/* A longest-prefix match tree. */
+struct trie_node {
+ uint32_t prefix; /* Prefix bits for this node, MSB first. */
+ uint8_t nbits; /* Never zero, except for the root node. */
+ unsigned int n_rules; /* Number of rules that have this prefix. */
+ struct trie_node *edges[2]; /* Both NULL if leaf. */
+};
+
+/* Max bits per node. Must fit in struct trie_node's 'prefix'.
+ * Also tested with 16, 8, and 5 to stress the implementation. */
+#define TRIE_PREFIX_BITS 32
+
+/* Return at least 'plen' bits of the 'prefix', starting at bit offset 'ofs'.
+ * Prefixes are in the network byte order, and the offset 0 corresponds to
+ * the most significant bit of the first byte. The offset can be read as
+ * "how many bits to skip from the start of the prefix starting at 'pr'". */
+static uint32_t
+raw_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
+{
+ uint32_t prefix;
+
+ pr += ofs / 32; /* Where to start. */
+ ofs %= 32; /* How many bits to skip at 'pr'. */
+
+ prefix = ntohl(*pr) << ofs; /* Get the first 32 - ofs bits. */
+ if (plen > 32 - ofs) { /* Need more than we have already? */
+ prefix |= ntohl(*++pr) >> (32 - ofs);
}
+ /* Return with possible unwanted bits at the end. */
+ return prefix;
}
-/* Returns true if 'a' and 'b' match, ignoring fields for which the wildcards
- * in 'wildcards' are set. 'nw_src_mask' and 'nw_dst_mask' must be those that
- * would be set for 'wildcards' by cls_rule_set_masks(). 'field_idx' is the
- * index of the first field to be compared; fields before 'field_idx' are
- * assumed to match. (Always returns true if 'field_idx' is CLS_N_FIELDS.) */
-static bool
-rules_match(const struct cls_rule *a, const struct cls_rule *b,
- uint32_t wildcards, uint32_t nw_src_mask, uint32_t nw_dst_mask,
- int field_idx)
-{
- /* This is related to Duff's device (see
- * http://en.wikipedia.org/wiki/Duff's_device). */
- switch (field_idx) {
-#define CLS_FIELD(WILDCARDS, MEMBER, NAME) \
- case CLS_F_IDX_##NAME: \
- if (!field_matches(&a->flow, &b->flow, \
- wildcards, nw_src_mask, nw_dst_mask, \
- WILDCARDS, offsetof(flow_t, MEMBER), \
- sizeof a->flow.MEMBER)) { \
- return false; \
- } \
- /* Fall though */
- CLS_FIELDS
-#undef CLS_FIELD
+/* Return min(TRIE_PREFIX_BITS, plen) bits of the 'prefix', starting at bit
+ * offset 'ofs'. Prefixes are in the network byte order, and the offset 0
+ * corresponds to the most significant bit of the first byte. The offset can
+ * be read as "how many bits to skip from the start of the prefix starting at
+ * 'pr'". */
+static uint32_t
+trie_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
+{
+ if (!plen) {
+ return 0;
+ }
+ if (plen > TRIE_PREFIX_BITS) {
+ plen = TRIE_PREFIX_BITS; /* Get at most TRIE_PREFIX_BITS. */
+ }
+ /* Return with unwanted bits cleared. */
+ return raw_get_prefix(pr, ofs, plen) & ~0u << (32 - plen);
+}
+
+/* Return the number of equal bits in 'nbits' of 'prefix's MSBs and a 'value'
+ * starting at "MSB 0"-based offset 'ofs'. */
+static unsigned int
+prefix_equal_bits(uint32_t prefix, unsigned int nbits, const ovs_be32 value[],
+ unsigned int ofs)
+{
+ uint64_t diff = prefix ^ raw_get_prefix(value, ofs, nbits);
+ /* Set the bit after the relevant bits to limit the result. */
+ return raw_clz64(diff << 32 | UINT64_C(1) << (63 - nbits));
+}
+
+/* Return the number of equal bits in 'node' prefix and a 'prefix' of length
+ * 'plen', starting at "MSB 0"-based offset 'ofs'. */
+static unsigned int
+trie_prefix_equal_bits(const struct trie_node *node, const ovs_be32 prefix[],
+ unsigned int ofs, unsigned int plen)
+{
+ return prefix_equal_bits(node->prefix, MIN(node->nbits, plen - ofs),
+ prefix, ofs);
+}
+
+/* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' can
+ * be greater than 31. */
+static unsigned int
+be_get_bit_at(const ovs_be32 value[], unsigned int ofs)
+{
+ return (((const uint8_t *)value)[ofs / 8] >> (7 - ofs % 8)) & 1u;
+}
+
+/* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' must
+ * be between 0 and 31, inclusive. */
+static unsigned int
+get_bit_at(const uint32_t prefix, unsigned int ofs)
+{
+ return (prefix >> (31 - ofs)) & 1u;
+}
+
+/* Create new branch. */
+static struct trie_node *
+trie_branch_create(const ovs_be32 *prefix, unsigned int ofs, unsigned int plen,
+ unsigned int n_rules)
+{
+ struct trie_node *node = xmalloc(sizeof *node);
+
+ node->prefix = trie_get_prefix(prefix, ofs, plen);
+
+ if (plen <= TRIE_PREFIX_BITS) {
+ node->nbits = plen;
+ node->edges[0] = NULL;
+ node->edges[1] = NULL;
+ node->n_rules = n_rules;
+ } else { /* Need intermediate nodes. */
+ struct trie_node *subnode = trie_branch_create(prefix,
+ ofs + TRIE_PREFIX_BITS,
+ plen - TRIE_PREFIX_BITS,
+ n_rules);
+ int bit = get_bit_at(subnode->prefix, 0);
+ node->nbits = TRIE_PREFIX_BITS;
+ node->edges[bit] = subnode;
+ node->edges[!bit] = NULL;
+ node->n_rules = 0;
+ }
+ return node;
+}
+
+static void
+trie_node_destroy(struct trie_node *node)
+{
+ free(node);
+}
+
+static void
+trie_destroy(struct trie_node *node)
+{
+ if (node) {
+ trie_destroy(node->edges[0]);
+ trie_destroy(node->edges[1]);
+ free(node);
}
- return true;
}
-/* Returns true if 'fixed' and 'wild' match. All fields in 'fixed' must have
- * fixed values; 'wild' may contain wildcards.
- *
- * 'field_idx' is the index of the first field to be compared; fields before
- * 'field_idx' are assumed to match. Always returns true if 'field_idx' is
- * CLS_N_FIELDS. */
static bool
-rules_match_1wild(const struct cls_rule *fixed, const struct cls_rule *wild,
- int field_idx)
+trie_is_leaf(const struct trie_node *trie)
{
- return rules_match(fixed, wild, wild->wc.wildcards, wild->wc.nw_src_mask,
- wild->wc.nw_dst_mask, field_idx);
+ return !trie->edges[0] && !trie->edges[1]; /* No children. */
}
-/* Searches 'bucket' for a rule that matches 'target'. Returns the
- * highest-priority match, if one is found, or a null pointer if there is no
- * match.
- *
- * 'field_idx' must be the index of the first wildcarded field in 'bucket'. */
-static struct cls_rule *
-search_bucket(struct cls_bucket *bucket, int field_idx,
- const struct cls_rule *target)
+static void
+mask_set_prefix_bits(struct flow_wildcards *wc, uint8_t be32ofs,
+ unsigned int nbits)
{
- struct cls_rule *pos;
+ ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
+ unsigned int i;
- if (!equal_fields(&bucket->fixed, &target->flow, field_idx)) {
- return NULL;
+ for (i = 0; i < nbits / 32; i++) {
+ mask[i] = OVS_BE32_MAX;
+ }
+ if (nbits % 32) {
+ mask[i] |= htonl(~0u << (32 - nbits % 32));
}
+}
+
+static bool
+mask_prefix_bits_set(const struct flow_wildcards *wc, uint8_t be32ofs,
+ unsigned int nbits)
+{
+ ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
+ unsigned int i;
+ ovs_be32 zeroes = 0;
+
+ for (i = 0; i < nbits / 32; i++) {
+ zeroes |= ~mask[i];
+ }
+ if (nbits % 32) {
+ zeroes |= ~mask[i] & htonl(~0u << (32 - nbits % 32));
+ }
+
+ return !zeroes; /* All 'nbits' bits set. */
+}
+
+static struct trie_node **
+trie_next_edge(struct trie_node *node, const ovs_be32 value[],
+ unsigned int ofs)
+{
+ return node->edges + be_get_bit_at(value, ofs);
+}
+
+static const struct trie_node *
+trie_next_node(const struct trie_node *node, const ovs_be32 value[],
+ unsigned int ofs)
+{
+ return node->edges[be_get_bit_at(value, ofs)];
+}
- LIST_FOR_EACH (pos, struct cls_rule, node.list, &bucket->rules) {
- if (rules_match_1wild(target, pos, field_idx)) {
- return pos;
+/* Return the prefix mask length necessary to find the longest-prefix match for
+ * the '*value' in the prefix tree 'node'.
+ * '*checkbits' is set to the number of bits in the prefix mask necessary to
+ * determine a mismatch, in case there are longer prefixes in the tree below
+ * the one that matched.
+ */
+static unsigned int
+trie_lookup_value(const struct trie_node *node, const ovs_be32 value[],
+ unsigned int *checkbits)
+{
+ unsigned int plen = 0, match_len = 0;
+ const struct trie_node *prev = NULL;
+
+ for (; node; prev = node, node = trie_next_node(node, value, plen)) {
+ unsigned int eqbits;
+ /* Check if this edge can be followed. */
+ eqbits = prefix_equal_bits(node->prefix, node->nbits, value, plen);
+ plen += eqbits;
+ if (eqbits < node->nbits) { /* Mismatch, nothing more to be found. */
+ /* Bit at offset 'plen' differed. */
+ *checkbits = plen + 1; /* Includes the first mismatching bit. */
+ return match_len;
+ }
+ /* Full match, check if rules exist at this prefix length. */
+ if (node->n_rules > 0) {
+ match_len = plen;
}
}
- return NULL;
+ /* Dead end, exclude the other branch if it exists. */
+ *checkbits = !prev || trie_is_leaf(prev) ? plen : plen + 1;
+ return match_len;
}
-/* Searches 'table' for a rule that matches 'target'. Returns the
- * highest-priority match, if one is found, or a null pointer if there is no
- * match.
- *
- * 'field_idx' must be the index of the first wildcarded field in 'table'. */
-static struct cls_rule *
-search_table(const struct hmap *table, int field_idx,
- const struct cls_rule *target)
+static unsigned int
+trie_lookup(const struct cls_trie *trie, const struct flow *flow,
+ unsigned int *checkbits)
{
- struct cls_bucket *bucket;
+ const struct mf_field *mf = trie->field;
+
+ /* Check that current flow matches the prerequisites for the trie
+ * field. Some match fields are used for multiple purposes, so we
+ * must check that the trie is relevant for this flow. */
+ if (mf_are_prereqs_ok(mf, flow)) {
+ return trie_lookup_value(trie->root,
+ &((ovs_be32 *)flow)[mf->flow_be32ofs],
+ checkbits);
+ }
+ *checkbits = 0; /* Value not used in this case. */
+ return UINT_MAX;
+}
- switch (hmap_count(table)) {
- /* In these special cases there's no need to hash. */
- case 0:
- return NULL;
- case 1:
- bucket = CONTAINER_OF(hmap_first(table), struct cls_bucket, hmap_node);
- return search_bucket(bucket, field_idx, target);
+/* Returns the length of a prefix match mask for the field 'mf' in 'minimask'.
+ * Returns the u32 offset to the miniflow data in '*miniflow_index', if
+ * 'miniflow_index' is not NULL. */
+static unsigned int
+minimask_get_prefix_len(const struct minimask *minimask,
+ const struct mf_field *mf)
+{
+ unsigned int nbits = 0, mask_tz = 0; /* Non-zero when end of mask seen. */
+ uint8_t u32_ofs = mf->flow_be32ofs;
+ uint8_t u32_end = u32_ofs + mf->n_bytes / 4;
+
+ for (; u32_ofs < u32_end; ++u32_ofs) {
+ uint32_t mask;
+ mask = ntohl((OVS_FORCE ovs_be32)minimask_get(minimask, u32_ofs));
+
+ /* Validate mask, count the mask length. */
+ if (mask_tz) {
+ if (mask) {
+ return 0; /* No bits allowed after mask ended. */
+ }
+ } else {
+ if (~mask & (~mask + 1)) {
+ return 0; /* Mask not contiguous. */
+ }
+ mask_tz = ctz32(mask);
+ nbits += 32 - mask_tz;
+ }
}
- HMAP_FOR_EACH_WITH_HASH (bucket, struct cls_bucket, hmap_node,
- hash_fields(&target->flow, field_idx), table) {
- struct cls_rule *rule = search_bucket(bucket, field_idx, target);
- if (rule) {
- return rule;
+ return nbits;
+}
+
+/*
+ * This is called only when mask prefix is known to be CIDR and non-zero.
+ * Relies on the fact that the flow and mask have the same map, and since
+ * the mask is CIDR, the storage for the flow field exists even if it
+ * happened to be zeros.
+ */
+static const ovs_be32 *
+minimatch_get_prefix(const struct minimatch *match, const struct mf_field *mf)
+{
+ return (OVS_FORCE const ovs_be32 *)match->flow.values +
+ count_1bits(match->flow.map & ((UINT64_C(1) << mf->flow_be32ofs) - 1));
+}
+
+/* Insert rule in to the prefix tree.
+ * 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
+ * in 'rule'. */
+static void
+trie_insert(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
+{
+ const ovs_be32 *prefix = minimatch_get_prefix(&rule->match, trie->field);
+ struct trie_node *node;
+ struct trie_node **edge;
+ int ofs = 0;
+
+ /* Walk the tree. */
+ for (edge = &trie->root;
+ (node = *edge) != NULL;
+ edge = trie_next_edge(node, prefix, ofs)) {
+ unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
+ ofs += eqbits;
+ if (eqbits < node->nbits) {
+ /* Mismatch, new node needs to be inserted above. */
+ int old_branch = get_bit_at(node->prefix, eqbits);
+
+ /* New parent node. */
+ *edge = trie_branch_create(prefix, ofs - eqbits, eqbits,
+ ofs == mlen ? 1 : 0);
+
+ /* Adjust old node for its new position in the tree. */
+ node->prefix <<= eqbits;
+ node->nbits -= eqbits;
+ (*edge)->edges[old_branch] = node;
+
+ /* Check if need a new branch for the new rule. */
+ if (ofs < mlen) {
+ (*edge)->edges[!old_branch]
+ = trie_branch_create(prefix, ofs, mlen - ofs, 1);
+ }
+ return;
+ }
+ /* Full match so far. */
+
+ if (ofs == mlen) {
+ /* Full match at the current node, rule needs to be added here. */
+ node->n_rules++;
+ return;
}
}
- return NULL;
+ /* Must insert a new tree branch for the new rule. */
+ *edge = trie_branch_create(prefix, ofs, mlen - ofs, 1);
}
-static struct cls_rule *
-search_exact_table(const struct classifier *cls, size_t hash,
- const flow_t *target)
+/* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
+ * in 'rule'. */
+static void
+trie_remove(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
{
- struct cls_rule *rule;
+ const ovs_be32 *prefix = minimatch_get_prefix(&rule->match, trie->field);
+ struct trie_node *node;
+ struct trie_node **edges[sizeof(union mf_value) * 8];
+ int depth = 0, ofs = 0;
+
+ /* Walk the tree. */
+ for (edges[depth] = &trie->root;
+ (node = *edges[depth]) != NULL;
+ edges[++depth] = trie_next_edge(node, prefix, ofs)) {
+ unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
+ if (eqbits < node->nbits) {
+ /* Mismatch, nothing to be removed. This should never happen, as
+ * only rules in the classifier are ever removed. */
+ break; /* Log a warning. */
+ }
+ /* Full match so far. */
+ ofs += eqbits;
- HMAP_FOR_EACH_WITH_HASH (rule, struct cls_rule, node.hmap,
- hash, &cls->exact_table) {
- if (flow_equal(&rule->flow, target)) {
- return rule;
+ if (ofs == mlen) {
+ /* Full prefix match at the current node, remove rule here. */
+ if (!node->n_rules) {
+ break; /* Log a warning. */
+ }
+ node->n_rules--;
+
+ /* Check if can prune the tree. */
+ while (!node->n_rules && !(node->edges[0] && node->edges[1])) {
+ /* No rules and at most one child node, remove this node. */
+ struct trie_node *next;
+ next = node->edges[0] ? node->edges[0] : node->edges[1];
+
+ if (next) {
+ if (node->nbits + next->nbits > TRIE_PREFIX_BITS) {
+ break; /* Cannot combine. */
+ }
+ /* Combine node with next. */
+ next->prefix = node->prefix | next->prefix >> node->nbits;
+ next->nbits += node->nbits;
+ }
+ trie_node_destroy(node);
+ /* Update the parent's edge. */
+ *edges[depth] = next;
+ if (next || !depth) {
+ /* Branch not pruned or at root, nothing more to do. */
+ break;
+ }
+ node = *edges[--depth];
+ }
+ return;
}
}
- return NULL;
+ /* Cannot go deeper. This should never happen, since only rules
+ * that actually exist in the classifier are ever removed. */
+ VLOG_WARN("Trying to remove non-existing rule from a prefix trie.");
}