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ovs/lib/classifier.c
Ben Pfaff 18080541d2 classifier: Add support for conjunctive matches. 
A "conjunctive match" allows higher-level matches in the flow table, such
as set membership matches, without causing a cross-product explosion for
multidimensional matches.  Please refer to the documentation that this
commit adds to ovs-ofctl(8) for a better explanation, including an example.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jarno Rajahalme <jrajahalme@nicira.com>
2015-01-11 13:25:24 -08:00

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/*
* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "classifier.h"
#include "classifier-private.h"
#include <errno.h>
#include <netinet/in.h>
#include "byte-order.h"
#include "dynamic-string.h"
#include "odp-util.h"
#include "ofp-util.h"
#include "packets.h"
#include "util.h"
#include "openvswitch/vlog.h"
VLOG_DEFINE_THIS_MODULE(classifier);
struct trie_ctx;
/* A collection of "struct cls_conjunction"s currently embedded into a
* cls_match. */
struct cls_conjunction_set {
/* Link back to the cls_match.
*
* cls_conjunction_set is mostly used during classifier lookup, and, in
* turn, during classifier lookup the most used member of
* cls_conjunction_set is the rule's priority, so we cache it here for fast
* access. */
struct cls_match *match;
int priority; /* Cached copy of match->priority. */
/* Conjunction information.
*
* 'min_n_clauses' allows some optimization during classifier lookup. */
unsigned int n; /* Number of elements in 'conj'. */
unsigned int min_n_clauses; /* Smallest 'n' among elements of 'conj'. */
struct cls_conjunction conj[];
};
/* Ports trie depends on both ports sharing the same ovs_be32. */
#define TP_PORTS_OFS32 (offsetof(struct flow, tp_src) / 4)
BUILD_ASSERT_DECL(TP_PORTS_OFS32 == offsetof(struct flow, tp_dst) / 4);
BUILD_ASSERT_DECL(TP_PORTS_OFS32 % 2 == 0);
#define TP_PORTS_OFS64 (TP_PORTS_OFS32 / 2)
static size_t
cls_conjunction_set_size(size_t n)
{
return (sizeof(struct cls_conjunction_set)
+ n * sizeof(struct cls_conjunction));
}
static struct cls_conjunction_set *
cls_conjunction_set_alloc(struct cls_match *match,
const struct cls_conjunction conj[], size_t n)
{
if (n) {
size_t min_n_clauses = conj[0].n_clauses;
for (size_t i = 1; i < n; i++) {
min_n_clauses = MIN(min_n_clauses, conj[i].n_clauses);
}
struct cls_conjunction_set *set = xmalloc(cls_conjunction_set_size(n));
set->match = match;
set->priority = match->priority;
set->n = n;
set->min_n_clauses = min_n_clauses;
memcpy(set->conj, conj, n * sizeof *conj);
return set;
} else {
return NULL;
}
}
static struct cls_match *
cls_match_alloc(const struct cls_rule *rule,
const struct cls_conjunction conj[], size_t n)
{
int count = count_1bits(rule->match.flow.map);
struct cls_match *cls_match
= xmalloc(sizeof *cls_match - sizeof cls_match->flow.inline_values
+ MINIFLOW_VALUES_SIZE(count));
rculist_init(&cls_match->list);
*CONST_CAST(const struct cls_rule **, &cls_match->cls_rule) = rule;
*CONST_CAST(int *, &cls_match->priority) = rule->priority;
miniflow_clone_inline(CONST_CAST(struct miniflow *, &cls_match->flow),
&rule->match.flow, count);
ovsrcu_set_hidden(&cls_match->conj_set,
cls_conjunction_set_alloc(cls_match, conj, n));
return cls_match;
}
static struct cls_subtable *find_subtable(const struct classifier *cls,
const struct minimask *);
static struct cls_subtable *insert_subtable(struct classifier *cls,
const struct minimask *);
static void destroy_subtable(struct classifier *cls, struct cls_subtable *);
static const struct cls_match *find_match_wc(const struct cls_subtable *,
const struct flow *,
struct trie_ctx *,
unsigned int n_tries,
struct flow_wildcards *);
static struct cls_match *find_equal(const struct cls_subtable *,
const struct miniflow *, uint32_t hash);
static inline const struct cls_match *
next_rule_in_list__(const struct cls_match *rule)
{
const struct cls_match *next = NULL;
next = OBJECT_CONTAINING(rculist_next(&rule->list), next, list);
return next;
}
static inline const struct cls_match *
next_rule_in_list(const struct cls_match *rule)
{
const struct cls_match *next = next_rule_in_list__(rule);
return next->priority < rule->priority ? next : NULL;
}
static inline struct cls_match *
next_rule_in_list_protected__(struct cls_match *rule)
{
struct cls_match *next = NULL;
next = OBJECT_CONTAINING(rculist_next_protected(&rule->list), next, list);
return next;
}
static inline struct cls_match *
next_rule_in_list_protected(struct cls_match *rule)
{
struct cls_match *next = next_rule_in_list_protected__(rule);
return next->priority < rule->priority ? next : NULL;
}
/* 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_PROTECTED(RULE, HEAD) \
for ((RULE) = (HEAD); (RULE) != NULL; \
(RULE) = next_rule_in_list_protected(RULE))
static unsigned int minimask_get_prefix_len(const struct minimask *,
const struct mf_field *);
static void trie_init(struct classifier *cls, int trie_idx,
const struct mf_field *);
static unsigned int trie_lookup(const struct cls_trie *, const struct flow *,
union mf_value *plens);
static unsigned int trie_lookup_value(const rcu_trie_ptr *,
const ovs_be32 value[], ovs_be32 plens[],
unsigned int value_bits);
static void trie_destroy(rcu_trie_ptr *);
static void trie_insert(struct cls_trie *, const struct cls_rule *, int mlen);
static void trie_insert_prefix(rcu_trie_ptr *, const ovs_be32 *prefix,
int mlen);
static void trie_remove(struct cls_trie *, const struct cls_rule *, int mlen);
static void trie_remove_prefix(rcu_trie_ptr *, const ovs_be32 *prefix,
int mlen);
static void mask_set_prefix_bits(struct flow_wildcards *, uint8_t be32ofs,
unsigned int n_bits);
static bool mask_prefix_bits_set(const struct flow_wildcards *,
uint8_t be32ofs, unsigned int n_bits);
/* cls_rule. */
static inline void
cls_rule_init__(struct cls_rule *rule, unsigned int priority)
{
rculist_init(&rule->node);
rule->priority = priority;
rule->cls_match = NULL;
}
/* 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().
*
* Clients should not use priority INT_MIN. (OpenFlow uses priorities between
* 0 and UINT16_MAX, inclusive.) */
void
cls_rule_init(struct cls_rule *rule, const struct match *match, int priority)
{
cls_rule_init__(rule, priority);
minimatch_init(&rule->match, match);
}
/* Same as cls_rule_init() for initialization from a "struct minimatch". */
void
cls_rule_init_from_minimatch(struct cls_rule *rule,
const struct minimatch *match, int priority)
{
cls_rule_init__(rule, priority);
minimatch_clone(&rule->match, match);
}
/* Initializes 'dst' as a copy of 'src'.
*
* The caller must eventually destroy 'dst' with cls_rule_destroy(). */
void
cls_rule_clone(struct cls_rule *dst, const struct cls_rule *src)
{
cls_rule_init__(dst, src->priority);
minimatch_clone(&dst->match, &src->match);
}
/* Initializes 'dst' with the data in 'src', destroying 'src'.
* 'src' must be a cls_rule NOT in a classifier.
*
* The caller must eventually destroy 'dst' with cls_rule_destroy(). */
void
cls_rule_move(struct cls_rule *dst, struct cls_rule *src)
{
ovs_assert(!src->cls_match); /* Must not be in a classifier. */
cls_rule_init__(dst, src->priority);
minimatch_move(&dst->match, &src->match);
}
/* Frees memory referenced by 'rule'. Doesn't free 'rule' itself (it's
* normally embedded into a larger structure).
*
* ('rule' must not currently be in a classifier.) */
void
cls_rule_destroy(struct cls_rule *rule)
{
ovs_assert(!rule->cls_match); /* Must not be in a classifier. */
/* Check that the rule has been properly removed from the classifier and
* that the destruction only happens after the RCU grace period, or that
* the rule was never inserted to the classifier in the first place. */
ovs_assert(rculist_next_protected(&rule->node) == RCULIST_POISON
|| rculist_is_empty(&rule->node));
minimatch_destroy(&rule->match);
}
void
cls_rule_set_conjunctions(struct cls_rule *cr,
const struct cls_conjunction *conj, size_t n)
{
struct cls_match *match = cr->cls_match;
struct cls_conjunction_set *old
= ovsrcu_get_protected(struct cls_conjunction_set *, &match->conj_set);
struct cls_conjunction *old_conj = old ? old->conj : NULL;
unsigned int old_n = old ? old->n : 0;
if (old_n != n || (n && memcmp(old_conj, conj, n * sizeof *conj))) {
if (old) {
ovsrcu_postpone(free, old);
}
ovsrcu_set(&match->conj_set,
cls_conjunction_set_alloc(match, conj, n));
}
}
/* 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);
}
/* Initializes 'cls' as a classifier that initially contains no classification
* rules. */
void
classifier_init(struct classifier *cls, const uint8_t *flow_segments)
{
cls->n_rules = 0;
cmap_init(&cls->subtables_map);
pvector_init(&cls->subtables);
cmap_init(&cls->partitions);
cls->n_flow_segments = 0;
if (flow_segments) {
while (cls->n_flow_segments < CLS_MAX_INDICES
&& *flow_segments < FLOW_U64S) {
cls->flow_segments[cls->n_flow_segments++] = *flow_segments++;
}
}
cls->n_tries = 0;
for (int i = 0; i < CLS_MAX_TRIES; i++) {
trie_init(cls, i, NULL);
}
cls->publish = true;
}
/* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
* caller's responsibility.
* May only be called after all the readers have been terminated. */
void
classifier_destroy(struct classifier *cls)
{
if (cls) {
struct cls_partition *partition;
struct cls_subtable *subtable;
int i;
for (i = 0; i < cls->n_tries; i++) {
trie_destroy(&cls->tries[i].root);
}
CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
destroy_subtable(cls, subtable);
}
cmap_destroy(&cls->subtables_map);
CMAP_FOR_EACH (partition, cmap_node, &cls->partitions) {
ovsrcu_postpone(free, partition);
}
cmap_destroy(&cls->partitions);
pvector_destroy(&cls->subtables);
}
}
/* Set the fields for which prefix lookup should be performed. */
bool
classifier_set_prefix_fields(struct classifier *cls,
const enum mf_field_id *trie_fields,
unsigned int n_fields)
{
const struct mf_field * new_fields[CLS_MAX_TRIES];
struct mf_bitmap fields = MF_BITMAP_INITIALIZER;
int i, n_tries = 0;
bool changed = false;
for (i = 0; i < n_fields && n_tries < 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 (bitmap_is_set(fields.bm, trie_fields[i])) {
/* Duplicate field, there is no need to build more than
* one index for any one field. */
continue;
}
bitmap_set1(fields.bm, trie_fields[i]);
new_fields[n_tries] = NULL;
if (n_tries >= cls->n_tries || field != cls->tries[n_tries].field) {
new_fields[n_tries] = field;
changed = true;
}
n_tries++;
}
if (changed || n_tries < cls->n_tries) {
struct cls_subtable *subtable;
/* Trie configuration needs to change. Disable trie lookups
* for the tries that are changing and wait all the current readers
* with the old configuration to be done. */
changed = false;
CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
for (i = 0; i < cls->n_tries; i++) {
if ((i < n_tries && new_fields[i]) || i >= n_tries) {
if (subtable->trie_plen[i]) {
subtable->trie_plen[i] = 0;
changed = true;
}
}
}
}
/* Synchronize if any readers were using tries. The readers may
* temporarily function without the trie lookup based optimizations. */
if (changed) {
/* ovsrcu_synchronize() functions as a memory barrier, so it does
* not matter that subtable->trie_plen is not atomic. */
ovsrcu_synchronize();
}
/* Now set up the tries. */
for (i = 0; i < n_tries; i++) {
if (new_fields[i]) {
trie_init(cls, i, new_fields[i]);
}
}
/* Destroy the rest, if any. */
for (; i < cls->n_tries; i++) {
trie_init(cls, i, NULL);
}
cls->n_tries = n_tries;
return true;
}
return false; /* No change. */
}
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);
} else {
ovsrcu_set_hidden(&trie->root, NULL);
}
trie->field = field;
/* Add existing rules to the new trie. */
CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
unsigned int plen;
plen = field ? minimask_get_prefix_len(&subtable->mask, field) : 0;
if (plen) {
struct cls_match *head;
CMAP_FOR_EACH (head, cmap_node, &subtable->rules) {
trie_insert(trie, head->cls_rule, plen);
}
}
/* Initialize subtable's prefix length on this field. This will
* allow readers to use the trie. */
atomic_thread_fence(memory_order_release);
subtable->trie_plen[trie_idx] = plen;
}
}
/* Returns true if 'cls' contains no classification rules, false otherwise.
* Checking the cmap requires no locking. */
bool
classifier_is_empty(const struct classifier *cls)
{
return cmap_is_empty(&cls->subtables_map);
}
/* Returns the number of rules in 'cls'. */
int
classifier_count(const struct classifier *cls)
{
/* n_rules is an int, so in the presence of concurrent writers this will
* return either the old or a new value. */
return cls->n_rules;
}
static uint32_t
hash_metadata(ovs_be64 metadata)
{
return hash_uint64((OVS_FORCE uint64_t) metadata);
}
static struct cls_partition *
find_partition(const struct classifier *cls, ovs_be64 metadata, uint32_t hash)
{
struct cls_partition *partition;
CMAP_FOR_EACH_WITH_HASH (partition, cmap_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)
{
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);
cmap_insert(&cls->partitions, &partition->cmap_node, hash);
}
tag_tracker_add(&partition->tracker, &partition->tags, subtable->tag);
return partition;
}
static inline ovs_be32 minimatch_get_ports(const struct minimatch *match)
{
/* Could optimize to use the same map if needed for fast path. */
return MINIFLOW_GET_BE32(&match->flow, tp_src)
& MINIFLOW_GET_BE32(&match->mask.masks, tp_src);
}
static void
subtable_replace_head_rule(struct classifier *cls OVS_UNUSED,
struct cls_subtable *subtable,
struct cls_match *head, struct cls_match *new,
uint32_t hash, uint32_t ihash[CLS_MAX_INDICES])
{
/* Rule's data is already in the tries. */
new->partition = head->partition; /* Steal partition, if any. */
head->partition = NULL;
for (int i = 0; i < subtable->n_indices; i++) {
cmap_replace(&subtable->indices[i], &head->index_nodes[i],
&new->index_nodes[i], ihash[i]);
}
cmap_replace(&subtable->rules, &head->cmap_node, &new->cmap_node, hash);
}
/* 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 destroying it with cls_rule_destroy(), after RCU
* grace period has passed (see ovsrcu_postpone()).
*
* 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.
*/
const struct cls_rule *
classifier_replace(struct classifier *cls, const struct cls_rule *rule,
const struct cls_conjunction *conjs, size_t n_conjs)
{
struct cls_match *new = cls_match_alloc(rule, conjs, n_conjs);
struct cls_subtable *subtable;
uint32_t ihash[CLS_MAX_INDICES];
uint8_t prev_be64ofs = 0;
struct cls_match *head;
size_t n_rules = 0;
uint32_t basis;
uint32_t hash;
int i;
CONST_CAST(struct cls_rule *, rule)->cls_match = new;
subtable = find_subtable(cls, &rule->match.mask);
if (!subtable) {
subtable = insert_subtable(cls, &rule->match.mask);
}
/* Compute hashes in segments. */
basis = 0;
for (i = 0; i < subtable->n_indices; i++) {
ihash[i] = minimatch_hash_range(&rule->match, prev_be64ofs,
subtable->index_ofs[i], &basis);
prev_be64ofs = subtable->index_ofs[i];
}
hash = minimatch_hash_range(&rule->match, prev_be64ofs, FLOW_U64S, &basis);
head = find_equal(subtable, &rule->match.flow, hash);
if (!head) {
/* Add rule to tries.
*
* Concurrent readers might miss seeing the rule until this update,
* which might require being fixed up by revalidation later. */
for (i = 0; i < cls->n_tries; i++) {
if (subtable->trie_plen[i]) {
trie_insert(&cls->tries[i], rule, subtable->trie_plen[i]);
}
}
/* Add rule to ports trie. */
if (subtable->ports_mask_len) {
/* We mask the value to be inserted to always have the wildcarded
* bits in known (zero) state, so we can include them in comparison
* and they will always match (== their original value does not
* matter). */
ovs_be32 masked_ports = minimatch_get_ports(&rule->match);
trie_insert_prefix(&subtable->ports_trie, &masked_ports,
subtable->ports_mask_len);
}
/* Add rule to partitions.
*
* Concurrent readers might miss seeing the rule until this update,
* which might require being fixed up by revalidation later. */
new->partition = NULL;
if (minimask_get_metadata_mask(&rule->match.mask) == OVS_BE64_MAX) {
ovs_be64 metadata = miniflow_get_metadata(&rule->match.flow);
new->partition = create_partition(cls, subtable, metadata);
}
/* Make rule visible to lookups. */
/* Add new node to segment indices.
*
* Readers may find the rule in the indices before the rule is visible
* in the subtables 'rules' map. This may result in us losing the
* opportunity to quit lookups earlier, resulting in sub-optimal
* wildcarding. This will be fixed later by revalidation (always
* scheduled after flow table changes). */
for (i = 0; i < subtable->n_indices; i++) {
cmap_insert(&subtable->indices[i], &new->index_nodes[i], ihash[i]);
}
n_rules = cmap_insert(&subtable->rules, &new->cmap_node, hash);
} else { /* Equal rules exist in the classifier already. */
struct cls_match *iter;
/* Scan the list for the insertion point that will keep the list in
* order of decreasing priority. */
FOR_EACH_RULE_IN_LIST_PROTECTED (iter, head) {
if (rule->priority >= iter->priority) {
break;
}
}
/* 'iter' now at the insertion point or NULL it at end. */
if (iter) {
struct cls_rule *old;
if (rule->priority == iter->priority) {
rculist_replace(&new->list, &iter->list);
old = CONST_CAST(struct cls_rule *, iter->cls_rule);
} else {
rculist_insert(&iter->list, &new->list);
old = NULL;
}
/* Replace the existing head in data structures, if rule is the new
* head. */
if (iter == head) {
subtable_replace_head_rule(cls, subtable, head, new, hash,
ihash);
}
if (old) {
struct cls_conjunction_set *conj_set;
conj_set = ovsrcu_get_protected(struct cls_conjunction_set *,
&iter->conj_set);
if (conj_set) {
ovsrcu_postpone(free, conj_set);
}
ovsrcu_postpone(free, iter);
old->cls_match = NULL;
/* No change in subtable's max priority or max count. */
/* Make rule visible to iterators. */
rculist_replace(CONST_CAST(struct rculist *, &rule->node),
&old->node);
/* Return displaced rule. Caller is responsible for keeping it
* around until all threads quiesce. */
return old;
}
} else {
rculist_push_back(&head->list, &new->list);
}
}
/* Make rule visible to iterators. */
rculist_push_back(&subtable->rules_list,
CONST_CAST(struct rculist *, &rule->node));
/* Rule was added, not replaced. Update 'subtable's 'max_priority' and
* 'max_count', if necessary.
*
* The rule was already inserted, but concurrent readers may not see the
* rule yet as the subtables vector is not updated yet. This will have to
* be fixed by revalidation later. */
if (n_rules == 1) {
subtable->max_priority = rule->priority;
subtable->max_count = 1;
pvector_insert(&cls->subtables, subtable, rule->priority);
} else if (rule->priority == subtable->max_priority) {
++subtable->max_count;
} else if (rule->priority > subtable->max_priority) {
subtable->max_priority = rule->priority;
subtable->max_count = 1;
pvector_change_priority(&cls->subtables, subtable, rule->priority);
}
/* Nothing was replaced. */
cls->n_rules++;
if (cls->publish) {
pvector_publish(&cls->subtables);
}
return NULL;
}
/* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller
* must not modify or free it.
*
* '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(struct classifier *cls, const struct cls_rule *rule,
const struct cls_conjunction conj[], size_t n_conj)
{
const struct cls_rule *displaced_rule
= classifier_replace(cls, rule, conj, n_conj);
ovs_assert(!displaced_rule);
}
/* 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.
*
* Does nothing if 'rule' has been already removed, or was never inserted.
*
* Returns the removed rule, or NULL, if it was already removed.
*/
const struct cls_rule *
classifier_remove(struct classifier *cls, const struct cls_rule *rule)
{
struct cls_partition *partition;
struct cls_match *cls_match;
struct cls_conjunction_set *conj_set;
struct cls_subtable *subtable;
struct cls_match *prev;
struct cls_match *next;
int i;
uint32_t basis = 0, hash, ihash[CLS_MAX_INDICES];
uint8_t prev_be64ofs = 0;
size_t n_rules;
cls_match = rule->cls_match;
if (!cls_match) {
return NULL;
}
/* Mark as removed. */
CONST_CAST(struct cls_rule *, rule)->cls_match = NULL;
/* Remove 'rule' from the subtable's rules list. */
rculist_remove(CONST_CAST(struct rculist *, &rule->node));
INIT_CONTAINER(prev, rculist_back_protected(&cls_match->list), list);
INIT_CONTAINER(next, rculist_next(&cls_match->list), list);
/* Remove from the list of equal rules. */
rculist_remove(&cls_match->list);
/* Check if this is NOT a head rule. */
if (prev->priority > rule->priority) {
/* Not the highest priority rule, no need to check subtable's
* 'max_priority'. */
goto free;
}
subtable = find_subtable(cls, &rule->match.mask);
ovs_assert(subtable);
for (i = 0; i < subtable->n_indices; i++) {
ihash[i] = minimatch_hash_range(&rule->match, prev_be64ofs,
subtable->index_ofs[i], &basis);
prev_be64ofs = subtable->index_ofs[i];
}
hash = minimatch_hash_range(&rule->match, prev_be64ofs, FLOW_U64S, &basis);
/* Head rule. Check if 'next' is an identical, lower-priority rule that
* will replace 'rule' in the data structures. */
if (next->priority < rule->priority) {
subtable_replace_head_rule(cls, subtable, cls_match, next, hash,
ihash);
goto check_priority;
}
/* 'rule' is last of the kind in the classifier, must remove from all the
* data structures. */
if (subtable->ports_mask_len) {
ovs_be32 masked_ports = minimatch_get_ports(&rule->match);
trie_remove_prefix(&subtable->ports_trie,
&masked_ports, subtable->ports_mask_len);
}
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++) {
cmap_remove(&subtable->indices[i], &cls_match->index_nodes[i],
ihash[i]);
}
n_rules = cmap_remove(&subtable->rules, &cls_match->cmap_node, hash);
partition = cls_match->partition;
if (partition) {
tag_tracker_subtract(&partition->tracker, &partition->tags,
subtable->tag);
if (!partition->tags) {
cmap_remove(&cls->partitions, &partition->cmap_node,
hash_metadata(partition->metadata));
ovsrcu_postpone(free, partition);
}
}
if (n_rules == 0) {
destroy_subtable(cls, subtable);
} else {
check_priority:
if (subtable->max_priority == rule->priority
&& --subtable->max_count == 0) {
/* Find the new 'max_priority' and 'max_count'. */
struct cls_match *head;
int max_priority = INT_MIN;
CMAP_FOR_EACH (head, cmap_node, &subtable->rules) {
if (head->priority > max_priority) {
max_priority = head->priority;
subtable->max_count = 1;
} else if (head->priority == max_priority) {
++subtable->max_count;
}
}
subtable->max_priority = max_priority;
pvector_change_priority(&cls->subtables, subtable, max_priority);
}
}
if (cls->publish) {
pvector_publish(&cls->subtables);
}
free:
conj_set = ovsrcu_get_protected(struct cls_conjunction_set *,
&cls_match->conj_set);
if (conj_set) {
ovsrcu_postpone(free, conj_set);
}
ovsrcu_postpone(free, cls_match);
cls->n_rules--;
return rule;
}
/* Prefix tree context. Valid when 'lookup_done' is true. Can skip all
* subtables which have a prefix match on the trie field, but whose prefix
* length is not indicated in 'match_plens'. For example, a subtable that
* has a 8-bit trie field prefix match can be skipped if
* !be_get_bit_at(&match_plens, 8 - 1). If skipped, 'maskbits' prefix bits
* must be unwildcarded to make datapath flow only match 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 maskbits; /* Prefix length needed to avoid false matches. */
union mf_value match_plens; /* Bitmask of prefix lengths with possible
* 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;
}
struct conjunctive_match {
struct hmap_node hmap_node;
uint32_t id;
uint64_t clauses;
};
static struct conjunctive_match *
find_conjunctive_match__(struct hmap *matches, uint64_t id, uint32_t hash)
{
struct conjunctive_match *m;
HMAP_FOR_EACH_IN_BUCKET (m, hmap_node, hash, matches) {
if (m->id == id) {
return m;
}
}
return NULL;
}
static bool
find_conjunctive_match(const struct cls_conjunction_set *set,
unsigned int max_n_clauses, struct hmap *matches,
struct conjunctive_match *cm_stubs, size_t n_cm_stubs,
uint32_t *idp)
{
const struct cls_conjunction *c;
if (max_n_clauses < set->min_n_clauses) {
return false;
}
for (c = set->conj; c < &set->conj[set->n]; c++) {
struct conjunctive_match *cm;
uint32_t hash;
if (c->n_clauses > max_n_clauses) {
continue;
}
hash = hash_int(c->id, 0);
cm = find_conjunctive_match__(matches, c->id, hash);
if (!cm) {
size_t n = hmap_count(matches);
cm = n < n_cm_stubs ? &cm_stubs[n] : xmalloc(sizeof *cm);
hmap_insert(matches, &cm->hmap_node, hash);
cm->id = c->id;
cm->clauses = UINT64_MAX << (c->n_clauses & 63);
}
cm->clauses |= UINT64_C(1) << c->clause;
if (cm->clauses == UINT64_MAX) {
*idp = cm->id;
return true;
}
}
return false;
}
static void
free_conjunctive_matches(struct hmap *matches,
struct conjunctive_match *cm_stubs, size_t n_cm_stubs)
{
if (hmap_count(matches) > n_cm_stubs) {
struct conjunctive_match *cm, *next;
HMAP_FOR_EACH_SAFE (cm, next, hmap_node, matches) {
if (!(cm >= cm_stubs && cm < &cm_stubs[n_cm_stubs])) {
free(cm);
}
}
}
hmap_destroy(matches);
}
/* Like classifier_lookup(), except that support for conjunctive matches can be
* configured with 'allow_conjunctive_matches'. That feature is not exposed
* externally because turning off conjunctive matches is only useful to avoid
* recursion within this function itself.
*
* 'flow' is non-const to allow for temporary modifications during the lookup.
* Any changes are restored before returning. */
static const struct cls_rule *
classifier_lookup__(const struct classifier *cls, struct flow *flow,
struct flow_wildcards *wc, bool allow_conjunctive_matches)
{
const struct cls_partition *partition;
struct trie_ctx trie_ctx[CLS_MAX_TRIES];
const struct cls_match *match;
tag_type tags;
/* Highest-priority flow in 'cls' that certainly matches 'flow'. */
const struct cls_match *hard = NULL;
int hard_pri = INT_MIN; /* hard ? hard->priority : INT_MIN. */
/* Highest-priority conjunctive flows in 'cls' matching 'flow'. Since
* these are (components of) conjunctive flows, we can only know whether
* the full conjunctive flow matches after seeing multiple of them. Thus,
* we refer to these as "soft matches". */
struct cls_conjunction_set *soft_stub[64];
struct cls_conjunction_set **soft = soft_stub;
size_t n_soft = 0, allocated_soft = ARRAY_SIZE(soft_stub);
int soft_pri = INT_MIN; /* n_soft ? MAX(soft[*]->priority) : INT_MIN. */
/* Synchronize for cls->n_tries and subtable->trie_plen. They can change
* when table configuration changes, which happens typically only on
* startup. */
atomic_thread_fence(memory_order_acquire);
/* 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 = (cmap_is_empty(&cls->partitions)
? NULL
: find_partition(cls, flow->metadata,
hash_metadata(flow->metadata)));
tags = partition ? partition->tags : TAG_ARBITRARY;
/* Initialize trie contexts for find_match_wc(). */
for (int i = 0; i < cls->n_tries; i++) {
trie_ctx_init(&trie_ctx[i], &cls->tries[i]);
}
/* Main loop. */
struct cls_subtable *subtable;
PVECTOR_FOR_EACH_PRIORITY (subtable, hard_pri, 2, sizeof *subtable,
&cls->subtables) {
struct cls_conjunction_set *conj_set;
/* Skip subtables not in our partition. */
if (!tag_intersects(tags, subtable->tag)) {
continue;
}
/* Skip subtables with no match, or where the match is lower-priority
* than some certain match we've already found. */
match = find_match_wc(subtable, flow, trie_ctx, cls->n_tries, wc);
if (!match || match->priority <= hard_pri) {
continue;
}
conj_set = ovsrcu_get(struct cls_conjunction_set *, &match->conj_set);
if (!conj_set) {
/* 'match' isn't part of a conjunctive match. It's the best
* certain match we've got so far, since we know that it's
* higher-priority than hard_pri.
*
* (There might be a higher-priority conjunctive match. We can't
* tell yet.) */
hard = match;
hard_pri = hard->priority;
} else if (allow_conjunctive_matches) {
/* 'match' is part of a conjunctive match. Add it to the list. */
if (OVS_UNLIKELY(n_soft >= allocated_soft)) {
struct cls_conjunction_set **old_soft = soft;
allocated_soft *= 2;
soft = xmalloc(allocated_soft * sizeof *soft);
memcpy(soft, old_soft, n_soft * sizeof *soft);
if (old_soft != soft_stub) {
free(old_soft);
}
}
soft[n_soft++] = conj_set;
/* Keep track of the highest-priority soft match. */
if (soft_pri < match->priority) {
soft_pri = match->priority;
}
}
}
/* In the common case, at this point we have no soft matches and we can
* return immediately. (We do the same thing if we have potential soft
* matches but none of them are higher-priority than our hard match.) */
if (hard_pri >= soft_pri) {
if (soft != soft_stub) {
free(soft);
}
return hard ? hard->cls_rule : NULL;
}
/* At this point, we have some soft matches. We might also have a hard
* match; if so, its priority is lower than the highest-priority soft
* match. */
/* Soft match loop.
*
* Check whether soft matches are real matches. */
for (;;) {
/* Delete soft matches that are null. This only happens in second and
* subsequent iterations of the soft match loop, when we drop back from
* a high-priority soft match to a lower-priority one.
*
* Also, delete soft matches whose priority is less than or equal to
* the hard match's priority. In the first iteration of the soft
* match, these can be in 'soft' because the earlier main loop found
* the soft match before the hard match. In second and later iteration
* of the soft match loop, these can be in 'soft' because we dropped
* back from a high-priority soft match to a lower-priority soft match.
*
* It is tempting to delete soft matches that cannot be satisfied
* because there are fewer soft matches than required to satisfy any of
* their conjunctions, but we cannot do that because there might be
* lower priority soft or hard matches with otherwise identical
* matches. (We could special case those here, but there's no
* need--we'll do so at the bottom of the soft match loop anyway and
* this duplicates less code.)
*
* It's also tempting to break out of the soft match loop if 'n_soft ==
* 1' but that would also miss lower-priority hard matches. We could
* special case that also but again there's no need. */
for (int i = 0; i < n_soft; ) {
if (!soft[i] || soft[i]->priority <= hard_pri) {
soft[i] = soft[--n_soft];
} else {
i++;
}
}
if (!n_soft) {
break;
}
/* Find the highest priority among the soft matches. (We know this
* must be higher than the hard match's priority; otherwise we would
* have deleted all of the soft matches in the previous loop.) Count
* the number of soft matches that have that priority. */
soft_pri = INT_MIN;
int n_soft_pri = 0;
for (int i = 0; i < n_soft; i++) {
if (soft[i]->priority > soft_pri) {
soft_pri = soft[i]->priority;
n_soft_pri = 1;
} else if (soft[i]->priority == soft_pri) {
n_soft_pri++;
}
}
ovs_assert(soft_pri > hard_pri);
/* Look for a real match among the highest-priority soft matches.
*
* It's unusual to have many conjunctive matches, so we use stubs to
* avoid calling malloc() in the common case. An hmap has a built-in
* stub for up to 2 hmap_nodes; possibly, we would benefit a variant
* with a bigger stub. */
struct conjunctive_match cm_stubs[16];
struct hmap matches;
hmap_init(&matches);
for (int i = 0; i < n_soft; i++) {
uint32_t id;
if (soft[i]->priority == soft_pri
&& find_conjunctive_match(soft[i], n_soft_pri, &matches,
cm_stubs, ARRAY_SIZE(cm_stubs),
&id)) {
uint32_t saved_conj_id = flow->conj_id;
const struct cls_rule *rule;
flow->conj_id = id;
rule = classifier_lookup__(cls, flow, wc, false);
flow->conj_id = saved_conj_id;
if (rule) {
free_conjunctive_matches(&matches,
cm_stubs, ARRAY_SIZE(cm_stubs));
if (soft != soft_stub) {
free(soft);
}
return rule;
}
}
}
free_conjunctive_matches(&matches, cm_stubs, ARRAY_SIZE(cm_stubs));
/* There's no real match among the highest-priority soft matches.
* However, if any of those soft matches has a lower-priority but
* otherwise identical flow match, then we need to consider those for
* soft or hard matches.
*
* The next iteration of the soft match loop will delete any null
* pointers we put into 'soft' (and some others too). */
for (int i = 0; i < n_soft; i++) {
if (soft[i]->priority != soft_pri) {
continue;
}
/* Find next-lower-priority flow with identical flow match. */
match = next_rule_in_list(soft[i]->match);
if (match) {
soft[i] = ovsrcu_get(struct cls_conjunction_set *,
&match->conj_set);
if (!soft[i]) {
/* The flow is a hard match; don't treat as a soft
* match. */
if (match->priority > hard_pri) {
hard = match;
hard_pri = hard->priority;
}
}
} else {
/* No such lower-priority flow (probably the common case). */
soft[i] = NULL;
}
}
}
if (soft != soft_stub) {
free(soft);
}
return hard ? hard->cls_rule : NULL;
}
/* 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.
*
* 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()).
*
* 'flow' is non-const to allow for temporary modifications during the lookup.
* Any changes are restored before returning. */
const struct cls_rule *
classifier_lookup(const struct classifier *cls, struct flow *flow,
struct flow_wildcards *wc)
{
return classifier_lookup__(cls, flow, wc, true);
}
/* 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. */
const struct cls_rule *
classifier_find_rule_exactly(const struct classifier *cls,
const struct cls_rule *target)
{
const struct cls_match *head, *rule;
const struct cls_subtable *subtable;
subtable = find_subtable(cls, &target->match.mask);
if (!subtable) {
return NULL;
}
head = find_equal(subtable, &target->match.flow,
miniflow_hash_in_minimask(&target->match.flow,
&target->match.mask, 0));
if (!head) {
return NULL;
}
FOR_EACH_RULE_IN_LIST (rule, head) {
if (target->priority >= rule->priority) {
return target->priority == rule->priority ? rule->cls_rule : NULL;
}
}
return NULL;
}
/* 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. */
const struct cls_rule *
classifier_find_match_exactly(const struct classifier *cls,
const struct match *target, int priority)
{
const 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.
*
* A trivial example of overlapping rules is two rules matching disjoint sets
* of fields. E.g., if one rule matches only on port number, while another only
* on dl_type, any packet from that specific port and with that specific
* dl_type could match both, if the rules also have the same priority. */
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. */
PVECTOR_FOR_EACH_PRIORITY (subtable, target->priority - 1, 2,
sizeof(struct cls_subtable), &cls->subtables) {
uint64_t storage[FLOW_U64S];
struct minimask mask;
const struct cls_rule *rule;
minimask_combine(&mask, &target->match.mask, &subtable->mask, storage);
RCULIST_FOR_EACH (rule, node, &subtable->rules_list) {
if (rule->priority == target->priority
&& miniflow_equal_in_minimask(&target->match.flow,
&rule->match.flow, &mask)) {
return true;
}
}
}
return false;
}
/* 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));
}
/* 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 const struct cls_rule *
search_subtable(const struct cls_subtable *subtable,
struct cls_cursor *cursor)
{
if (!cursor->target
|| !minimask_has_extra(&subtable->mask, &cursor->target->match.mask)) {
const struct cls_rule *rule;
RCULIST_FOR_EACH (rule, node, &subtable->rules_list) {
if (rule_matches(rule, cursor->target)) {
return rule;
}
}
}
return NULL;
}
/* Initializes 'cursor' for iterating through rules in 'cls', and returns the
* first matching cls_rule via '*pnode', or NULL if there are no matches.
*
* - 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. */
struct cls_cursor cls_cursor_start(const struct classifier *cls,
const struct cls_rule *target)
{
struct cls_cursor cursor;
struct cls_subtable *subtable;
cursor.cls = cls;
cursor.target = target && !cls_rule_is_catchall(target) ? target : NULL;
cursor.rule = NULL;
/* Find first rule. */
PVECTOR_CURSOR_FOR_EACH (subtable, &cursor.subtables,
&cursor.cls->subtables) {
const struct cls_rule *rule = search_subtable(subtable, &cursor);
if (rule) {
cursor.subtable = subtable;
cursor.rule = rule;
break;
}
}
return cursor;
}
static const struct cls_rule *
cls_cursor_next(struct cls_cursor *cursor)
{
const struct cls_rule *rule;
const struct cls_subtable *subtable;
rule = cursor->rule;
subtable = cursor->subtable;
RCULIST_FOR_EACH_CONTINUE (rule, node, &subtable->rules_list) {
if (rule_matches(rule, cursor->target)) {
return rule;
}
}
PVECTOR_CURSOR_FOR_EACH_CONTINUE (subtable, &cursor->subtables) {
rule = search_subtable(subtable, cursor);
if (rule) {
cursor->subtable = subtable;
return rule;
}
}
return NULL;
}
/* Sets 'cursor->rule' to the next matching cls_rule in 'cursor''s iteration,
* or to null if all matching rules have been visited. */
void
cls_cursor_advance(struct cls_cursor *cursor)
{
cursor->rule = cls_cursor_next(cursor);
}
static struct cls_subtable *
find_subtable(const struct classifier *cls, const struct minimask *mask)
{
struct cls_subtable *subtable;
CMAP_FOR_EACH_WITH_HASH (subtable, cmap_node, minimask_hash(mask, 0),
&cls->subtables_map) {
if (minimask_equal(mask, &subtable->mask)) {
return subtable;
}
}
return NULL;
}
/* The new subtable will be visible to the readers only after this. */
static struct cls_subtable *
insert_subtable(struct classifier *cls, const struct minimask *mask)
{
uint32_t hash = minimask_hash(mask, 0);
struct cls_subtable *subtable;
int i, index = 0;
struct flow_wildcards old, new;
uint8_t prev;
int count = count_1bits(mask->masks.map);
subtable = xzalloc(sizeof *subtable - sizeof mask->masks.inline_values
+ MINIFLOW_VALUES_SIZE(count));
cmap_init(&subtable->rules);
miniflow_clone_inline(CONST_CAST(struct miniflow *, &subtable->mask.masks),
&mask->masks, count);
/* 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)) {
cmap_init(&subtable->indices[index]);
*CONST_CAST(uint8_t *, &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_U64S);
if (flow_wildcards_equal(&new, &old)) {
--index;
*CONST_CAST(uint8_t *, &subtable->index_ofs[index]) = 0;
cmap_destroy(&subtable->indices[index]);
}
}
*CONST_CAST(uint8_t *, &subtable->n_indices) = index;
*CONST_CAST(tag_type *, &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);
}
/* Ports trie. */
ovsrcu_set_hidden(&subtable->ports_trie, NULL);
*CONST_CAST(int *, &subtable->ports_mask_len)
= 32 - ctz32(ntohl(MINIFLOW_GET_BE32(&mask->masks, tp_src)));
/* List of rules. */
rculist_init(&subtable->rules_list);
cmap_insert(&cls->subtables_map, &subtable->cmap_node, hash);
return subtable;
}
/* RCU readers may still access the subtable before it is actually freed. */
static void
destroy_subtable(struct classifier *cls, struct cls_subtable *subtable)
{
int i;
pvector_remove(&cls->subtables, subtable);
cmap_remove(&cls->subtables_map, &subtable->cmap_node,
minimask_hash(&subtable->mask, 0));
ovs_assert(ovsrcu_get_protected(struct trie_node *, &subtable->ports_trie)
== NULL);
ovs_assert(cmap_is_empty(&subtable->rules));
ovs_assert(rculist_is_empty(&subtable->rules_list));
for (i = 0; i < subtable->n_indices; i++) {
cmap_destroy(&subtable->indices[i]);
}
cmap_destroy(&subtable->rules);
ovsrcu_postpone(free, subtable);
}
struct range {
uint8_t start;
uint8_t end;
};
static unsigned int be_get_bit_at(const ovs_be32 value[], unsigned int ofs);
/* 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;
uint8_t be64ofs = be32ofs / 2;
/* Is the trie field within the current range of fields? */
if (be64ofs >= ofs.start && be64ofs < ofs.end) {
/* On-demand trie lookup. */
if (!ctx->lookup_done) {
memset(&ctx->match_plens, 0, sizeof ctx->match_plens);
ctx->maskbits = trie_lookup(ctx->trie, flow,
&ctx->match_plens);
ctx->lookup_done = true;
}
/* Possible to skip the rest of the subtable if subtable's
* prefix on the field is not included in the lookup result. */
if (!be_get_bit_at(&ctx->match_plens.be32, field_plen[j] - 1)) {
/* 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 relevant for the current
* packet. Hence the checks below. */
/* Check that the trie result will not unwildcard more bits
* than this subtable would otherwise. */
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 always unwildcarded. */
return true;
}
/* Can skip if the field is already unwildcarded. */
if (mask_prefix_bits_set(wc, be32ofs, ctx->maskbits)) {
return true;
}
}
}
}
}
return false;
}
/* Returns true if 'target' satisifies 'flow'/'mask', that is, if each bit
* for which 'flow', for which 'mask' has a bit set, specifies a particular
* value has the correct value in 'target'.
*
* This function is equivalent to miniflow_equal_flow_in_minimask(flow,
* target, mask) but this is faster because of the invariant that
* flow->map and mask->masks.map are the same, and that this version
* takes the 'wc'. */
static inline bool
miniflow_and_mask_matches_flow(const struct miniflow *flow,
const struct minimask *mask,
const struct flow *target)
{
const uint64_t *flowp = miniflow_get_values(flow);
const uint64_t *maskp = miniflow_get_values(&mask->masks);
int idx;
MAP_FOR_EACH_INDEX(idx, mask->masks.map) {
uint64_t diff = (*flowp++ ^ flow_u64_value(target, idx)) & *maskp++;
if (diff) {
return false;
}
}
return true;
}
static inline const struct cls_match *
find_match(const struct cls_subtable *subtable, const struct flow *flow,
uint32_t hash)
{
const struct cls_match *rule;
CMAP_FOR_EACH_WITH_HASH (rule, cmap_node, hash, &subtable->rules) {
if (miniflow_and_mask_matches_flow(&rule->flow, &subtable->mask,
flow)) {
return rule;
}
}
return NULL;
}
/* Returns true if 'target' satisifies 'flow'/'mask', that is, if each bit
* for which 'flow', for which 'mask' has a bit set, specifies a particular
* value has the correct value in 'target'.
*
* This function is equivalent to miniflow_and_mask_matches_flow() but this
* version fills in the mask bits in 'wc'. */
static inline bool
miniflow_and_mask_matches_flow_wc(const struct miniflow *flow,
const struct minimask *mask,
const struct flow *target,
struct flow_wildcards *wc)
{
const uint64_t *flowp = miniflow_get_values(flow);
const uint64_t *maskp = miniflow_get_values(&mask->masks);
int idx;
MAP_FOR_EACH_INDEX(idx, mask->masks.map) {
uint64_t mask = *maskp++;
uint64_t diff = (*flowp++ ^ flow_u64_value(target, idx)) & mask;
if (diff) {
/* Only unwildcard if none of the differing bits is already
* exact-matched. */
if (!(flow_u64_value(&wc->masks, idx) & diff)) {
/* Keep one bit of the difference. The selected bit may be
* different in big-endian v.s. little-endian systems. */
*flow_u64_lvalue(&wc->masks, idx) |= rightmost_1bit(diff);
}
return false;
}
/* Fill in the bits that were looked at. */
*flow_u64_lvalue(&wc->masks, idx) |= mask;
}
return true;
}
/* Unwildcard the fields looked up so far, if any. */
static void
fill_range_wc(const struct cls_subtable *subtable, struct flow_wildcards *wc,
uint8_t to)
{
if (to) {
flow_wildcards_fold_minimask_range(wc, &subtable->mask, 0, to);
}
}
static const struct cls_match *
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;
const struct cls_match *rule = NULL;
int i;
struct range ofs;
if (OVS_UNLIKELY(!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++) {
const struct cmap_node *inode;
ofs.end = subtable->index_ofs[i];
if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow,
wc)) {
/* 'wc' bits for the trie field set, now unwildcard the preceding
* bits used so far. */
fill_range_wc(subtable, wc, ofs.start);
return NULL;
}
hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
ofs.end, &basis);
inode = cmap_find(&subtable->indices[i], hash);
if (!inode) {
/* No match, can stop immediately, but must fold in the bits
* used in lookup so far. */
fill_range_wc(subtable, wc, ofs.end);
return NULL;
}
/* If we have narrowed down to a single rule already, check whether
* that rule matches. Either way, we're done.
*
* (Rare) hash collisions may cause us to miss the opportunity for this
* optimization. */
if (!cmap_node_next(inode)) {
ASSIGN_CONTAINER(rule, inode - i, index_nodes);
if (miniflow_and_mask_matches_flow_wc(&rule->flow, &subtable->mask,
flow, wc)) {
return rule;
}
return NULL;
}
ofs.start = ofs.end;
}
ofs.end = FLOW_U64S;
/* Trie check for the final range. */
if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow, wc)) {
fill_range_wc(subtable, wc, ofs.start);
return NULL;
}
hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
ofs.end, &basis);
rule = find_match(subtable, flow, hash);
if (!rule && subtable->ports_mask_len) {
/* Ports are always part of the final range, if any.
* No match was found for the ports. Use the ports trie to figure out
* which ports bits to unwildcard. */
unsigned int mbits;
ovs_be32 value, plens, mask;
mask = MINIFLOW_GET_BE32(&subtable->mask.masks, tp_src);
value = ((OVS_FORCE ovs_be32 *)flow)[TP_PORTS_OFS32] & mask;
mbits = trie_lookup_value(&subtable->ports_trie, &value, &plens, 32);
((OVS_FORCE ovs_be32 *)&wc->masks)[TP_PORTS_OFS32] |=
mask & be32_prefix_mask(mbits);
/* Unwildcard all bits in the mask upto the ports, as they were used
* to determine there is no match. */
fill_range_wc(subtable, wc, TP_PORTS_OFS64);
return NULL;
}
/* Must unwildcard all the fields, as they were looked at. */
flow_wildcards_fold_minimask(wc, &subtable->mask);
return rule;
}
static struct cls_match *
find_equal(const struct cls_subtable *subtable, const struct miniflow *flow,
uint32_t hash)
{
struct cls_match *head;
CMAP_FOR_EACH_WITH_HASH (head, cmap_node, hash, &subtable->rules) {
if (miniflow_equal(&head->flow, flow)) {
return head;
}
}
return NULL;
}
/* A longest-prefix match tree. */
/* 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;
}
/* 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 'n_bits' 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 n_bits, const ovs_be32 value[],
unsigned int ofs)
{
uint64_t diff = prefix ^ raw_get_prefix(value, ofs, n_bits);
/* Set the bit after the relevant bits to limit the result. */
return raw_clz64(diff << 32 | UINT64_C(1) << (63 - n_bits));
}
/* 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->n_bits, 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->n_bits = plen;
ovsrcu_set_hidden(&node->edges[0], NULL);
ovsrcu_set_hidden(&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->n_bits = TRIE_PREFIX_BITS;
ovsrcu_set_hidden(&node->edges[bit], subnode);
ovsrcu_set_hidden(&node->edges[!bit], NULL);
node->n_rules = 0;
}
return node;
}
static void
trie_node_destroy(const struct trie_node *node)
{
ovsrcu_postpone(free, CONST_CAST(struct trie_node *, node));
}
/* Copy a trie node for modification and postpone delete the old one. */
static struct trie_node *
trie_node_rcu_realloc(const struct trie_node *node)
{
struct trie_node *new_node = xmalloc(sizeof *node);
*new_node = *node;
trie_node_destroy(node);
return new_node;
}
static void
trie_destroy(rcu_trie_ptr *trie)
{
struct trie_node *node = ovsrcu_get_protected(struct trie_node *, trie);
if (node) {
ovsrcu_set_hidden(trie, NULL);
trie_destroy(&node->edges[0]);
trie_destroy(&node->edges[1]);
trie_node_destroy(node);
}
}
static bool
trie_is_leaf(const struct trie_node *trie)
{
/* No children? */
return !ovsrcu_get(struct trie_node *, &trie->edges[0])
&& !ovsrcu_get(struct trie_node *, &trie->edges[1]);
}
static void
mask_set_prefix_bits(struct flow_wildcards *wc, uint8_t be32ofs,
unsigned int n_bits)
{
ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
unsigned int i;
for (i = 0; i < n_bits / 32; i++) {
mask[i] = OVS_BE32_MAX;
}
if (n_bits % 32) {
mask[i] |= htonl(~0u << (32 - n_bits % 32));
}
}
static bool
mask_prefix_bits_set(const struct flow_wildcards *wc, uint8_t be32ofs,
unsigned int n_bits)
{
ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
unsigned int i;
ovs_be32 zeroes = 0;
for (i = 0; i < n_bits / 32; i++) {
zeroes |= ~mask[i];
}
if (n_bits % 32) {
zeroes |= ~mask[i] & htonl(~0u << (32 - n_bits % 32));
}
return !zeroes; /* All 'n_bits' bits set. */
}
static rcu_trie_ptr *
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 ovsrcu_get(struct trie_node *,
&node->edges[be_get_bit_at(value, ofs)]);
}
/* Set the bit at ("MSB 0"-based) offset 'ofs'. 'ofs' can be greater than 31.
*/
static void
be_set_bit_at(ovs_be32 value[], unsigned int ofs)
{
((uint8_t *)value)[ofs / 8] |= 1u << (7 - ofs % 8);
}
/* Returns 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.
* '*plens' will have a bit set for each prefix length that may have matching
* rules. The caller is responsible for clearing the '*plens' prior to
* calling this.
*/
static unsigned int
trie_lookup_value(const rcu_trie_ptr *trie, const ovs_be32 value[],
ovs_be32 plens[], unsigned int n_bits)
{
const struct trie_node *prev = NULL;
const struct trie_node *node = ovsrcu_get(struct trie_node *, trie);
unsigned int match_len = 0; /* Number of matching bits. */
for (; node; prev = node, node = trie_next_node(node, value, match_len)) {
unsigned int eqbits;
/* Check if this edge can be followed. */
eqbits = prefix_equal_bits(node->prefix, node->n_bits, value,
match_len);
match_len += eqbits;
if (eqbits < node->n_bits) { /* Mismatch, nothing more to be found. */
/* Bit at offset 'match_len' differed. */
return match_len + 1; /* Includes the first mismatching bit. */
}
/* Full match, check if rules exist at this prefix length. */
if (node->n_rules > 0) {
be_set_bit_at(plens, match_len - 1);
}
if (match_len >= n_bits) {
return n_bits; /* Full prefix. */
}
}
/* node == NULL. Full match so far, but we tried to follow an
* non-existing branch. Need to exclude the other branch if it exists
* (it does not if we were called on an empty trie or 'prev' is a leaf
* node). */
return !prev || trie_is_leaf(prev) ? match_len : match_len + 1;
}
static unsigned int
trie_lookup(const struct cls_trie *trie, const struct flow *flow,
union mf_value *plens)
{
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],
&plens->be32, mf->n_bits);
}
memset(plens, 0xff, sizeof *plens); /* All prefixes, no skipping. */
return 0; /* Value not used in this case. */
}
/* 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 n_bits = 0, mask_tz = 0; /* Non-zero when end of mask seen. */
uint8_t be32_ofs = mf->flow_be32ofs;
uint8_t be32_end = be32_ofs + mf->n_bytes / 4;
for (; be32_ofs < be32_end; ++be32_ofs) {
uint32_t mask = ntohl(minimask_get_be32(minimask, be32_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);
n_bits += 32 - mask_tz;
}
}
return n_bits;
}
/*
* 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 *)
(miniflow_get_values(&match->flow)
+ count_1bits(match->flow.map &
((UINT64_C(1) << mf->flow_be32ofs / 2) - 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)
{
trie_insert_prefix(&trie->root,
minimatch_get_prefix(&rule->match, trie->field), mlen);
}
static void
trie_insert_prefix(rcu_trie_ptr *edge, const ovs_be32 *prefix, int mlen)
{
struct trie_node *node;
int ofs = 0;
/* Walk the tree. */
for (; (node = ovsrcu_get_protected(struct trie_node *, edge));
edge = trie_next_edge(node, prefix, ofs)) {
unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
ofs += eqbits;
if (eqbits < node->n_bits) {
/* Mismatch, new node needs to be inserted above. */
int old_branch = get_bit_at(node->prefix, eqbits);
struct trie_node *new_parent;
new_parent = trie_branch_create(prefix, ofs - eqbits, eqbits,
ofs == mlen ? 1 : 0);
/* Copy the node to modify it. */
node = trie_node_rcu_realloc(node);
/* Adjust the new node for its new position in the tree. */
node->prefix <<= eqbits;
node->n_bits -= eqbits;
ovsrcu_set_hidden(&new_parent->edges[old_branch], node);
/* Check if need a new branch for the new rule. */
if (ofs < mlen) {
ovsrcu_set_hidden(&new_parent->edges[!old_branch],
trie_branch_create(prefix, ofs, mlen - ofs,
1));
}
ovsrcu_set(edge, new_parent); /* Publish changes. */
return;
}
/* Full match so far. */
if (ofs == mlen) {
/* Full match at the current node, rule needs to be added here. */
node->n_rules++;
return;
}
}
/* Must insert a new tree branch for the new rule. */
ovsrcu_set(edge, trie_branch_create(prefix, ofs, mlen - ofs, 1));
}
/* '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)
{
trie_remove_prefix(&trie->root,
minimatch_get_prefix(&rule->match, trie->field), mlen);
}
/* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
* in 'rule'. */
static void
trie_remove_prefix(rcu_trie_ptr *root, const ovs_be32 *prefix, int mlen)
{
struct trie_node *node;
rcu_trie_ptr *edges[sizeof(union mf_value) * 8];
int depth = 0, ofs = 0;
/* Walk the tree. */
for (edges[0] = root;
(node = ovsrcu_get_protected(struct trie_node *, edges[depth]));
edges[++depth] = trie_next_edge(node, prefix, ofs)) {
unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
if (eqbits < node->n_bits) {
/* 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;
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) {
struct trie_node *next,
*edge0 = ovsrcu_get_protected(struct trie_node *,
&node->edges[0]),
*edge1 = ovsrcu_get_protected(struct trie_node *,
&node->edges[1]);
if (edge0 && edge1) {
break; /* A branching point, cannot prune. */
}
/* Else have at most one child node, remove this node. */
next = edge0 ? edge0 : edge1;
if (next) {
if (node->n_bits + next->n_bits > TRIE_PREFIX_BITS) {
break; /* Cannot combine. */
}
next = trie_node_rcu_realloc(next); /* Modify. */
/* Combine node with next. */
next->prefix = node->prefix | next->prefix >> node->n_bits;
next->n_bits += node->n_bits;
}
/* Update the parent's edge. */
ovsrcu_set(edges[depth], next); /* Publish changes. */
trie_node_destroy(node);
if (next || !depth) {
/* Branch not pruned or at root, nothing more to do. */
break;
}
node = ovsrcu_get_protected(struct trie_node *,
edges[--depth]);
}
return;
}
}
/* 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.");
}
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