mirror of
https://github.com/openvswitch/ovs
synced 2025-08-22 09:58:01 +00:00
71f21279f6
Shadowing is when a variable with a given name in an inner scope hides a different variable with the same name in a surrounding scope. This is generally undesirable because it can confuse programmers. This commit eliminates most of it. Found with -Wshadow=local in GCC 7. The repo is not really ready to enable this option by default because of a few cases that are harder to fix, and harmless, such as nested use of CMAP_FOR_EACH. Signed-off-by: Ben Pfaff <blp@ovn.org> Acked-by: Andy Zhou <azhou@ovn.org>
2177 lines
77 KiB
C
2177 lines
77 KiB
C
/*
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* Copyright (c) 2009-2017 Nicira, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <config.h>
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#include "classifier.h"
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#include "classifier-private.h"
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#include <errno.h>
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#include <netinet/in.h>
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#include "byte-order.h"
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#include "openvswitch/dynamic-string.h"
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#include "odp-util.h"
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#include "openvswitch/ofp-util.h"
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#include "packets.h"
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#include "util.h"
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struct trie_ctx;
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/* A collection of "struct cls_conjunction"s currently embedded into a
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* cls_match. */
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struct cls_conjunction_set {
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/* Link back to the cls_match.
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*
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* cls_conjunction_set is mostly used during classifier lookup, and, in
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* turn, during classifier lookup the most used member of
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* cls_conjunction_set is the rule's priority, so we cache it here for fast
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* access. */
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struct cls_match *match;
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int priority; /* Cached copy of match->priority. */
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/* Conjunction information.
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*
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* 'min_n_clauses' allows some optimization during classifier lookup. */
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unsigned int n; /* Number of elements in 'conj'. */
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unsigned int min_n_clauses; /* Smallest 'n' among elements of 'conj'. */
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struct cls_conjunction conj[];
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};
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/* Ports trie depends on both ports sharing the same ovs_be32. */
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#define TP_PORTS_OFS32 (offsetof(struct flow, tp_src) / 4)
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BUILD_ASSERT_DECL(TP_PORTS_OFS32 == offsetof(struct flow, tp_dst) / 4);
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BUILD_ASSERT_DECL(TP_PORTS_OFS32 % 2 == 0);
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#define TP_PORTS_OFS64 (TP_PORTS_OFS32 / 2)
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static size_t
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cls_conjunction_set_size(size_t n)
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{
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return (sizeof(struct cls_conjunction_set)
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+ n * sizeof(struct cls_conjunction));
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}
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static struct cls_conjunction_set *
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cls_conjunction_set_alloc(struct cls_match *match,
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const struct cls_conjunction conj[], size_t n)
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{
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if (n) {
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size_t min_n_clauses = conj[0].n_clauses;
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for (size_t i = 1; i < n; i++) {
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min_n_clauses = MIN(min_n_clauses, conj[i].n_clauses);
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}
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struct cls_conjunction_set *set = xmalloc(cls_conjunction_set_size(n));
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set->match = match;
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set->priority = match->priority;
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set->n = n;
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set->min_n_clauses = min_n_clauses;
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memcpy(set->conj, conj, n * sizeof *conj);
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return set;
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} else {
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return NULL;
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}
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}
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static struct cls_match *
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cls_match_alloc(const struct cls_rule *rule, ovs_version_t version,
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const struct cls_conjunction conj[], size_t n)
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{
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size_t count = miniflow_n_values(rule->match.flow);
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struct cls_match *cls_match
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= xmalloc(sizeof *cls_match + MINIFLOW_VALUES_SIZE(count));
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ovsrcu_init(&cls_match->next, NULL);
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*CONST_CAST(const struct cls_rule **, &cls_match->cls_rule) = rule;
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*CONST_CAST(int *, &cls_match->priority) = rule->priority;
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/* Make rule initially invisible. */
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cls_match->versions = VERSIONS_INITIALIZER(version, version);
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miniflow_clone(CONST_CAST(struct miniflow *, &cls_match->flow),
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rule->match.flow, count);
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ovsrcu_set_hidden(&cls_match->conj_set,
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cls_conjunction_set_alloc(cls_match, conj, n));
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return cls_match;
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}
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static struct cls_subtable *find_subtable(const struct classifier *cls,
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const struct minimask *);
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static struct cls_subtable *insert_subtable(struct classifier *cls,
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const struct minimask *);
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static void destroy_subtable(struct classifier *cls, struct cls_subtable *);
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static const struct cls_match *find_match_wc(const struct cls_subtable *,
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ovs_version_t version,
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const struct flow *,
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struct trie_ctx *,
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unsigned int n_tries,
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struct flow_wildcards *);
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static struct cls_match *find_equal(const struct cls_subtable *,
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const struct miniflow *, uint32_t hash);
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/* Return the next visible (lower-priority) rule in the list. Multiple
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* identical rules with the same priority may exist transitionally, but when
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* versioning is used at most one of them is ever visible for lookups on any
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* given 'version'. */
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static inline const struct cls_match *
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next_visible_rule_in_list(const struct cls_match *rule, ovs_version_t version)
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{
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do {
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rule = cls_match_next(rule);
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} while (rule && !cls_match_visible_in_version(rule, version));
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return rule;
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}
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/* Type with maximum supported prefix length. */
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union trie_prefix {
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struct in6_addr ipv6; /* For sizing. */
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ovs_be32 be32; /* For access. */
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};
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static unsigned int minimask_get_prefix_len(const struct minimask *,
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const struct mf_field *);
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static void trie_init(struct classifier *cls, int trie_idx,
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const struct mf_field *);
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static unsigned int trie_lookup(const struct cls_trie *, const struct flow *,
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union trie_prefix *plens);
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static unsigned int trie_lookup_value(const rcu_trie_ptr *,
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const ovs_be32 value[], ovs_be32 plens[],
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unsigned int value_bits);
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static void trie_destroy(rcu_trie_ptr *);
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static void trie_insert(struct cls_trie *, const struct cls_rule *, int mlen);
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static void trie_insert_prefix(rcu_trie_ptr *, const ovs_be32 *prefix,
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int mlen);
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static void trie_remove(struct cls_trie *, const struct cls_rule *, int mlen);
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static void trie_remove_prefix(rcu_trie_ptr *, const ovs_be32 *prefix,
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int mlen);
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static void mask_set_prefix_bits(struct flow_wildcards *, uint8_t be32ofs,
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unsigned int n_bits);
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static bool mask_prefix_bits_set(const struct flow_wildcards *,
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uint8_t be32ofs, unsigned int n_bits);
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/* cls_rule. */
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static inline void
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cls_rule_init__(struct cls_rule *rule, unsigned int priority)
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{
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rculist_init(&rule->node);
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*CONST_CAST(int *, &rule->priority) = priority;
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ovsrcu_init(&rule->cls_match, NULL);
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}
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/* Initializes 'rule' to match packets specified by 'match' at the given
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* 'priority'. 'match' must satisfy the invariant described in the comment at
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* the definition of struct match.
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*
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* The caller must eventually destroy 'rule' with cls_rule_destroy().
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*
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* Clients should not use priority INT_MIN. (OpenFlow uses priorities between
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* 0 and UINT16_MAX, inclusive.) */
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void
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cls_rule_init(struct cls_rule *rule, const struct match *match, int priority)
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{
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cls_rule_init__(rule, priority);
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minimatch_init(CONST_CAST(struct minimatch *, &rule->match), match);
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}
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/* Same as cls_rule_init() for initialization from a "struct minimatch". */
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void
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cls_rule_init_from_minimatch(struct cls_rule *rule,
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const struct minimatch *match, int priority)
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{
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cls_rule_init__(rule, priority);
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minimatch_clone(CONST_CAST(struct minimatch *, &rule->match), match);
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}
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/* Initializes 'dst' as a copy of 'src'.
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*
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* The caller must eventually destroy 'dst' with cls_rule_destroy(). */
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void
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cls_rule_clone(struct cls_rule *dst, const struct cls_rule *src)
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{
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cls_rule_init__(dst, src->priority);
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minimatch_clone(CONST_CAST(struct minimatch *, &dst->match), &src->match);
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}
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/* Initializes 'dst' with the data in 'src', destroying 'src'.
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*
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* 'src' must be a cls_rule NOT in a classifier.
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*
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* The caller must eventually destroy 'dst' with cls_rule_destroy(). */
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void
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cls_rule_move(struct cls_rule *dst, struct cls_rule *src)
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{
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cls_rule_init__(dst, src->priority);
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minimatch_move(CONST_CAST(struct minimatch *, &dst->match),
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CONST_CAST(struct minimatch *, &src->match));
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}
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/* Frees memory referenced by 'rule'. Doesn't free 'rule' itself (it's
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* normally embedded into a larger structure).
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*
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* ('rule' must not currently be in a classifier.) */
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void
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cls_rule_destroy(struct cls_rule *rule)
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OVS_NO_THREAD_SAFETY_ANALYSIS
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{
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/* Must not be in a classifier. */
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ovs_assert(!get_cls_match_protected(rule));
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/* Check that the rule has been properly removed from the classifier. */
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ovs_assert(rule->node.prev == RCULIST_POISON
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|| rculist_is_empty(&rule->node));
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rculist_poison__(&rule->node); /* Poisons also the next pointer. */
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minimatch_destroy(CONST_CAST(struct minimatch *, &rule->match));
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}
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/* This may only be called by the exclusive writer. */
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void
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cls_rule_set_conjunctions(struct cls_rule *cr,
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const struct cls_conjunction *conj, size_t n)
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{
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struct cls_match *match = get_cls_match_protected(cr);
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struct cls_conjunction_set *old
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= ovsrcu_get_protected(struct cls_conjunction_set *, &match->conj_set);
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struct cls_conjunction *old_conj = old ? old->conj : NULL;
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unsigned int old_n = old ? old->n : 0;
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if (old_n != n || (n && memcmp(old_conj, conj, n * sizeof *conj))) {
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if (old) {
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ovsrcu_postpone(free, old);
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}
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ovsrcu_set(&match->conj_set,
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cls_conjunction_set_alloc(match, conj, n));
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}
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}
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/* Returns true if 'a' and 'b' match the same packets at the same priority,
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* false if they differ in some way. */
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bool
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cls_rule_equal(const struct cls_rule *a, const struct cls_rule *b)
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{
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return a->priority == b->priority && minimatch_equal(&a->match, &b->match);
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}
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/* Appends a string describing 'rule' to 's'. */
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void
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cls_rule_format(const struct cls_rule *rule, const struct tun_table *tun_table,
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const struct ofputil_port_map *port_map, struct ds *s)
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{
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minimatch_format(&rule->match, tun_table, port_map, s, rule->priority);
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}
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/* Returns true if 'rule' matches every packet, false otherwise. */
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bool
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cls_rule_is_catchall(const struct cls_rule *rule)
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{
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return minimask_is_catchall(rule->match.mask);
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}
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/* Makes 'rule' invisible in 'remove_version'. Once that version is used in
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* lookups, the caller should remove 'rule' via ovsrcu_postpone().
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*
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* 'rule' must be in a classifier.
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* This may only be called by the exclusive writer. */
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void
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cls_rule_make_invisible_in_version(const struct cls_rule *rule,
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ovs_version_t remove_version)
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{
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struct cls_match *cls_match = get_cls_match_protected(rule);
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ovs_assert(remove_version >= cls_match->versions.add_version);
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cls_match_set_remove_version(cls_match, remove_version);
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}
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/* This undoes the change made by cls_rule_make_invisible_in_version().
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*
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* 'rule' must be in a classifier.
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* This may only be called by the exclusive writer. */
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void
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cls_rule_restore_visibility(const struct cls_rule *rule)
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{
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cls_match_set_remove_version(get_cls_match_protected(rule),
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OVS_VERSION_NOT_REMOVED);
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}
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/* Return true if 'rule' is visible in 'version'.
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*
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* 'rule' must be in a classifier. */
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bool
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cls_rule_visible_in_version(const struct cls_rule *rule, ovs_version_t version)
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{
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struct cls_match *cls_match = get_cls_match(rule);
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return cls_match && cls_match_visible_in_version(cls_match, version);
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}
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/* Initializes 'cls' as a classifier that initially contains no classification
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* rules. */
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void
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classifier_init(struct classifier *cls, const uint8_t *flow_segments)
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{
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cls->n_rules = 0;
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cmap_init(&cls->subtables_map);
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pvector_init(&cls->subtables);
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cls->n_flow_segments = 0;
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if (flow_segments) {
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while (cls->n_flow_segments < CLS_MAX_INDICES
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&& *flow_segments < FLOW_U64S) {
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cls->flow_segments[cls->n_flow_segments++] = *flow_segments++;
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}
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}
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cls->n_tries = 0;
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for (int i = 0; i < CLS_MAX_TRIES; i++) {
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trie_init(cls, i, NULL);
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}
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cls->publish = true;
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}
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/* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
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* caller's responsibility.
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* May only be called after all the readers have been terminated. */
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void
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classifier_destroy(struct classifier *cls)
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{
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if (cls) {
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struct cls_subtable *subtable;
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int i;
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for (i = 0; i < cls->n_tries; i++) {
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trie_destroy(&cls->tries[i].root);
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}
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CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
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destroy_subtable(cls, subtable);
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}
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cmap_destroy(&cls->subtables_map);
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pvector_destroy(&cls->subtables);
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}
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}
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/* Set the fields for which prefix lookup should be performed. */
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bool
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classifier_set_prefix_fields(struct classifier *cls,
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const enum mf_field_id *trie_fields,
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unsigned int n_fields)
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{
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const struct mf_field * new_fields[CLS_MAX_TRIES];
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struct mf_bitmap fields = MF_BITMAP_INITIALIZER;
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int i, n_tries = 0;
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bool changed = false;
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for (i = 0; i < n_fields && n_tries < CLS_MAX_TRIES; i++) {
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const struct mf_field *field = mf_from_id(trie_fields[i]);
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if (field->flow_be32ofs < 0 || field->n_bits % 32) {
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/* Incompatible field. This is the only place where we
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* enforce these requirements, but the rest of the trie code
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* depends on the flow_be32ofs to be non-negative and the
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* field length to be a multiple of 32 bits. */
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continue;
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}
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if (bitmap_is_set(fields.bm, trie_fields[i])) {
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/* Duplicate field, there is no need to build more than
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* one index for any one field. */
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continue;
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}
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bitmap_set1(fields.bm, trie_fields[i]);
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new_fields[n_tries] = NULL;
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if (n_tries >= cls->n_tries || field != cls->tries[n_tries].field) {
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new_fields[n_tries] = field;
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changed = true;
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}
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n_tries++;
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}
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if (changed || n_tries < cls->n_tries) {
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struct cls_subtable *subtable;
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/* Trie configuration needs to change. Disable trie lookups
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* for the tries that are changing and wait all the current readers
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* with the old configuration to be done. */
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changed = false;
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CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
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for (i = 0; i < cls->n_tries; i++) {
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if ((i < n_tries && new_fields[i]) || i >= n_tries) {
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if (subtable->trie_plen[i]) {
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subtable->trie_plen[i] = 0;
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changed = true;
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}
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}
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}
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}
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/* Synchronize if any readers were using tries. The readers may
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* temporarily function without the trie lookup based optimizations. */
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if (changed) {
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/* ovsrcu_synchronize() functions as a memory barrier, so it does
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* not matter that subtable->trie_plen is not atomic. */
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ovsrcu_synchronize();
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}
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/* Now set up the tries. */
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for (i = 0; i < n_tries; i++) {
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if (new_fields[i]) {
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trie_init(cls, i, new_fields[i]);
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}
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}
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/* Destroy the rest, if any. */
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for (; i < cls->n_tries; i++) {
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trie_init(cls, i, NULL);
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}
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cls->n_tries = n_tries;
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return true;
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}
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return false; /* No change. */
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}
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|
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static void
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trie_init(struct classifier *cls, int trie_idx, const struct mf_field *field)
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{
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struct cls_trie *trie = &cls->tries[trie_idx];
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struct cls_subtable *subtable;
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if (trie_idx < cls->n_tries) {
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trie_destroy(&trie->root);
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} else {
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ovsrcu_set_hidden(&trie->root, NULL);
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}
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trie->field = field;
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|
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/* Add existing rules to the new trie. */
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CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) {
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unsigned int plen;
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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 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);
|
||
}
|
||
|
||
/* Inserts 'rule' into 'cls' in 'version'. 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) that is visible in 'version', 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,
|
||
ovs_version_t version,
|
||
const struct cls_conjunction *conjs, size_t n_conjs)
|
||
{
|
||
struct cls_match *new;
|
||
struct cls_subtable *subtable;
|
||
uint32_t ihash[CLS_MAX_INDICES];
|
||
struct cls_match *head;
|
||
unsigned int mask_offset;
|
||
size_t n_rules = 0;
|
||
uint32_t basis;
|
||
uint32_t hash;
|
||
unsigned int i;
|
||
|
||
/* 'new' is initially invisible to lookups. */
|
||
new = cls_match_alloc(rule, version, conjs, n_conjs);
|
||
ovsrcu_set(&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;
|
||
mask_offset = 0;
|
||
for (i = 0; i < subtable->n_indices; i++) {
|
||
ihash[i] = minimatch_hash_range(&rule->match, subtable->index_maps[i],
|
||
&mask_offset, &basis);
|
||
}
|
||
hash = minimatch_hash_range(&rule->match, subtable->index_maps[i],
|
||
&mask_offset, &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 new node to segment indices. */
|
||
for (i = 0; i < subtable->n_indices; i++) {
|
||
ccmap_inc(&subtable->indices[i], ihash[i]);
|
||
}
|
||
n_rules = cmap_insert(&subtable->rules, &new->cmap_node, hash);
|
||
} else { /* Equal rules exist in the classifier already. */
|
||
struct cls_match *prev, *iter;
|
||
|
||
/* Scan the list for the insertion point that will keep the list in
|
||
* order of decreasing priority. Insert after rules marked invisible
|
||
* in any version of the same priority. */
|
||
FOR_EACH_RULE_IN_LIST_PROTECTED (iter, prev, head) {
|
||
if (rule->priority > iter->priority
|
||
|| (rule->priority == iter->priority
|
||
&& !cls_match_is_eventually_invisible(iter))) {
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* Replace 'iter' with 'new' or insert 'new' between 'prev' and
|
||
* 'iter'. */
|
||
if (iter) {
|
||
struct cls_rule *old;
|
||
|
||
if (rule->priority == iter->priority) {
|
||
cls_match_replace(prev, iter, new);
|
||
old = CONST_CAST(struct cls_rule *, iter->cls_rule);
|
||
} else {
|
||
cls_match_insert(prev, iter, new);
|
||
old = NULL;
|
||
}
|
||
|
||
/* Replace the existing head in data structures, if rule is the new
|
||
* head. */
|
||
if (iter == head) {
|
||
cmap_replace(&subtable->rules, &head->cmap_node,
|
||
&new->cmap_node, hash);
|
||
}
|
||
|
||
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_set(&old->cls_match, NULL); /* Marks old rule as removed
|
||
* from the classifier. */
|
||
ovsrcu_postpone(cls_match_free_cb, iter);
|
||
|
||
/* No change in subtable's max priority or max count. */
|
||
|
||
/* Make 'new' visible to lookups in the appropriate version. */
|
||
cls_match_set_remove_version(new, OVS_VERSION_NOT_REMOVED);
|
||
|
||
/* Make rule visible to iterators (immediately). */
|
||
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 {
|
||
/* 'new' is new node after 'prev' */
|
||
cls_match_insert(prev, iter, new);
|
||
}
|
||
}
|
||
|
||
/* Make 'new' visible to lookups in the appropriate version. */
|
||
cls_match_set_remove_version(new, OVS_VERSION_NOT_REMOVED);
|
||
|
||
/* Make rule visible to iterators (immediately). */
|
||
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,
|
||
ovs_version_t version, const struct cls_conjunction conj[],
|
||
size_t n_conj)
|
||
{
|
||
const struct cls_rule *displaced_rule
|
||
= classifier_replace(cls, rule, version, 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 *cls_rule)
|
||
{
|
||
struct cls_match *rule, *prev, *next, *head;
|
||
struct cls_conjunction_set *conj_set;
|
||
struct cls_subtable *subtable;
|
||
uint32_t basis = 0, hash, ihash[CLS_MAX_INDICES];
|
||
unsigned int mask_offset;
|
||
size_t n_rules;
|
||
unsigned int i;
|
||
|
||
rule = get_cls_match_protected(cls_rule);
|
||
if (!rule) {
|
||
return NULL;
|
||
}
|
||
/* Mark as removed. */
|
||
ovsrcu_set(&CONST_CAST(struct cls_rule *, cls_rule)->cls_match, NULL);
|
||
|
||
/* Remove 'cls_rule' from the subtable's rules list. */
|
||
rculist_remove(CONST_CAST(struct rculist *, &cls_rule->node));
|
||
|
||
subtable = find_subtable(cls, cls_rule->match.mask);
|
||
ovs_assert(subtable);
|
||
|
||
mask_offset = 0;
|
||
for (i = 0; i < subtable->n_indices; i++) {
|
||
ihash[i] = minimatch_hash_range(&cls_rule->match,
|
||
subtable->index_maps[i],
|
||
&mask_offset, &basis);
|
||
}
|
||
hash = minimatch_hash_range(&cls_rule->match, subtable->index_maps[i],
|
||
&mask_offset, &basis);
|
||
|
||
head = find_equal(subtable, cls_rule->match.flow, hash);
|
||
|
||
/* Check if the rule is not the head rule. */
|
||
if (rule != head) {
|
||
struct cls_match *iter;
|
||
|
||
/* Not the head rule, but potentially one with the same priority. */
|
||
/* Remove from the list of equal rules. */
|
||
FOR_EACH_RULE_IN_LIST_PROTECTED (iter, prev, head) {
|
||
if (rule == iter) {
|
||
break;
|
||
}
|
||
}
|
||
ovs_assert(iter == rule);
|
||
|
||
cls_match_remove(prev, rule);
|
||
|
||
goto check_priority;
|
||
}
|
||
|
||
/* 'rule' is the head rule. Check if there is another rule to
|
||
* replace 'rule' in the data structures. */
|
||
next = cls_match_next_protected(rule);
|
||
if (next) {
|
||
cmap_replace(&subtable->rules, &rule->cmap_node, &next->cmap_node,
|
||
hash);
|
||
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(&cls_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], cls_rule, subtable->trie_plen[i]);
|
||
}
|
||
}
|
||
|
||
/* Remove rule node from indices. */
|
||
for (i = 0; i < subtable->n_indices; i++) {
|
||
ccmap_dec(&subtable->indices[i], ihash[i]);
|
||
}
|
||
n_rules = cmap_remove(&subtable->rules, &rule->cmap_node, hash);
|
||
|
||
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'. */
|
||
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 the rule. */
|
||
conj_set = ovsrcu_get_protected(struct cls_conjunction_set *,
|
||
&rule->conj_set);
|
||
if (conj_set) {
|
||
ovsrcu_postpone(free, conj_set);
|
||
}
|
||
ovsrcu_postpone(cls_match_free_cb, rule);
|
||
cls->n_rules--;
|
||
|
||
return cls_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 trie_prefix 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, ovs_version_t version,
|
||
struct flow *flow, struct flow_wildcards *wc,
|
||
bool allow_conjunctive_matches)
|
||
{
|
||
struct trie_ctx trie_ctx[CLS_MAX_TRIES];
|
||
const struct cls_match *match;
|
||
/* 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);
|
||
|
||
/* 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 + 1, 2, sizeof *subtable,
|
||
&cls->subtables) {
|
||
struct cls_conjunction_set *conj_set;
|
||
|
||
/* 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, version, 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, version, 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_visible_rule_in_list(soft[i]->match, version);
|
||
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' and
|
||
* that is visible in 'version'. 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, ovs_version_t version,
|
||
struct flow *flow, struct flow_wildcards *wc)
|
||
{
|
||
return classifier_lookup__(cls, version, flow, wc, true);
|
||
}
|
||
|
||
/* Finds and returns a rule in 'cls' with exactly the same priority and
|
||
* matching criteria as 'target', and that is visible in 'version'.
|
||
* Only one such rule may ever exist. 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,
|
||
ovs_version_t version)
|
||
{
|
||
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;
|
||
}
|
||
CLS_MATCH_FOR_EACH (rule, head) {
|
||
if (rule->priority < target->priority) {
|
||
break; /* Not found. */
|
||
}
|
||
if (rule->priority == target->priority
|
||
&& cls_match_visible_in_version(rule, version)) {
|
||
return rule->cls_rule;
|
||
}
|
||
}
|
||
return NULL;
|
||
}
|
||
|
||
/* Finds and returns a rule in 'cls' with priority 'priority' and exactly the
|
||
* same matching criteria as 'target', and that is visible in 'version'.
|
||
* Returns a null pointer if 'cls' doesn't contain an exact match visible in
|
||
* 'version'. */
|
||
const struct cls_rule *
|
||
classifier_find_match_exactly(const struct classifier *cls,
|
||
const struct match *target, int priority,
|
||
ovs_version_t version)
|
||
{
|
||
const struct cls_rule *retval;
|
||
struct cls_rule cr;
|
||
|
||
cls_rule_init(&cr, target, priority);
|
||
retval = classifier_find_rule_exactly(cls, &cr, version);
|
||
cls_rule_destroy(&cr);
|
||
|
||
return retval;
|
||
}
|
||
|
||
/* Checks if 'target' would overlap any other rule in 'cls' in 'version'. Two
|
||
* rules are considered to overlap if both rules have the same priority and a
|
||
* packet could match both, and if both rules are visible in the same version.
|
||
*
|
||
* 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, ovs_version_t version)
|
||
{
|
||
struct cls_subtable *subtable;
|
||
|
||
/* Iterate subtables in the descending max priority order. */
|
||
PVECTOR_FOR_EACH_PRIORITY (subtable, target->priority, 2,
|
||
sizeof(struct cls_subtable), &cls->subtables) {
|
||
struct {
|
||
struct minimask mask;
|
||
uint64_t storage[FLOW_U64S];
|
||
} m;
|
||
const struct cls_rule *rule;
|
||
|
||
minimask_combine(&m.mask, target->match.mask, &subtable->mask,
|
||
m.storage);
|
||
|
||
RCULIST_FOR_EACH (rule, node, &subtable->rules_list) {
|
||
if (rule->priority == target->priority
|
||
&& miniflow_equal_in_minimask(target->match.flow,
|
||
rule->match.flow, &m.mask)
|
||
&& cls_rule_visible_in_version(rule, version)) {
|
||
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,
|
||
ovs_version_t version)
|
||
{
|
||
/* Rule may only match a target if it is visible in target's version. */
|
||
return cls_rule_visible_in_version(rule, version)
|
||
&& (!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, cursor->version)) {
|
||
return rule;
|
||
}
|
||
}
|
||
}
|
||
return NULL;
|
||
}
|
||
|
||
/* Initializes 'cursor' for iterating through rules in 'cls', and returns the
|
||
* cursor.
|
||
*
|
||
* - If 'target' is null, or if the 'target' is a catchall target, the
|
||
* cursor will visit every rule in 'cls' that is visible in 'version'.
|
||
*
|
||
* - If 'target' is nonnull, the cursor will visit each 'rule' in 'cls'
|
||
* such that cls_rule_is_loose_match(rule, target) returns true and that
|
||
* the rule is visible in 'version'.
|
||
*
|
||
* Ignores target->priority. */
|
||
struct cls_cursor
|
||
cls_cursor_start(const struct classifier *cls, const struct cls_rule *target,
|
||
ovs_version_t version)
|
||
{
|
||
struct cls_cursor cursor;
|
||
struct cls_subtable *subtable;
|
||
|
||
cursor.cls = cls;
|
||
cursor.target = target && !cls_rule_is_catchall(target) ? target : NULL;
|
||
cursor.version = version;
|
||
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, cursor->version)) {
|
||
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;
|
||
}
|
||
|
||
/* Initializes 'map' with a subset of 'miniflow''s maps that includes only the
|
||
* portions with u64-offset 'i' such that 'start' <= i < 'end'. Does not copy
|
||
* any data from 'miniflow' to 'map'. */
|
||
static struct flowmap
|
||
miniflow_get_map_in_range(const struct miniflow *miniflow, uint8_t start,
|
||
uint8_t end)
|
||
{
|
||
struct flowmap map;
|
||
size_t ofs = 0;
|
||
|
||
map = miniflow->map;
|
||
|
||
/* Clear the bits before 'start'. */
|
||
while (start >= MAP_T_BITS) {
|
||
start -= MAP_T_BITS;
|
||
ofs += MAP_T_BITS;
|
||
map.bits[start / MAP_T_BITS] = 0;
|
||
}
|
||
if (start > 0) {
|
||
flowmap_clear(&map, ofs, start);
|
||
}
|
||
|
||
/* Clear the bits starting at 'end'. */
|
||
if (end < FLOW_U64S) {
|
||
/* flowmap_clear() can handle at most MAP_T_BITS at a time. */
|
||
ovs_assert(FLOW_U64S - end <= MAP_T_BITS);
|
||
flowmap_clear(&map, end, FLOW_U64S - end);
|
||
}
|
||
return map;
|
||
}
|
||
|
||
/* 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 flowmap stage_map;
|
||
uint8_t prev;
|
||
size_t count = miniflow_n_values(&mask->masks);
|
||
|
||
subtable = xzalloc(sizeof *subtable + MINIFLOW_VALUES_SIZE(count));
|
||
cmap_init(&subtable->rules);
|
||
miniflow_clone(CONST_CAST(struct miniflow *, &subtable->mask.masks),
|
||
&mask->masks, count);
|
||
|
||
/* Init indices for segmented lookup, if any. */
|
||
prev = 0;
|
||
for (i = 0; i < cls->n_flow_segments; i++) {
|
||
stage_map = miniflow_get_map_in_range(&mask->masks, prev,
|
||
cls->flow_segments[i]);
|
||
/* Add an index if it adds mask bits. */
|
||
if (!flowmap_is_empty(stage_map)) {
|
||
ccmap_init(&subtable->indices[index]);
|
||
*CONST_CAST(struct flowmap *, &subtable->index_maps[index])
|
||
= stage_map;
|
||
index++;
|
||
}
|
||
prev = cls->flow_segments[i];
|
||
}
|
||
/* Map for the final stage. */
|
||
*CONST_CAST(struct flowmap *, &subtable->index_maps[index])
|
||
= miniflow_get_map_in_range(&mask->masks, prev, FLOW_U64S);
|
||
/* Check if the final stage adds any bits. */
|
||
if (index > 0) {
|
||
if (flowmap_is_empty(subtable->index_maps[index])) {
|
||
/* Remove the last index, as it has the same fields as the rules
|
||
* map. */
|
||
--index;
|
||
ccmap_destroy(&subtable->indices[index]);
|
||
}
|
||
}
|
||
*CONST_CAST(uint8_t *, &subtable->n_indices) = index;
|
||
|
||
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++) {
|
||
ccmap_destroy(&subtable->indices[i]);
|
||
}
|
||
cmap_destroy(&subtable->rules);
|
||
ovsrcu_postpone(free, subtable);
|
||
}
|
||
|
||
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 flowmap range_map, 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, and
|
||
is the trie field within the current range of fields? */
|
||
if (field_plen[j] &&
|
||
flowmap_is_set(&range_map, trie_ctx[j].be32ofs / 2)) {
|
||
struct trie_ctx *ctx = &trie_ctx[j];
|
||
|
||
/* 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, ctx->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, ctx->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);
|
||
const uint64_t *target_u64 = (const uint64_t *)target;
|
||
map_t map;
|
||
|
||
FLOWMAP_FOR_EACH_MAP (map, mask->masks.map) {
|
||
size_t idx;
|
||
|
||
MAP_FOR_EACH_INDEX (idx, map) {
|
||
if ((*flowp++ ^ target_u64[idx]) & *maskp++) {
|
||
return false;
|
||
}
|
||
}
|
||
target_u64 += MAP_T_BITS;
|
||
}
|
||
return true;
|
||
}
|
||
|
||
static inline const struct cls_match *
|
||
find_match(const struct cls_subtable *subtable, ovs_version_t version,
|
||
const struct flow *flow, uint32_t hash)
|
||
{
|
||
const struct cls_match *head, *rule;
|
||
|
||
CMAP_FOR_EACH_WITH_HASH (head, cmap_node, hash, &subtable->rules) {
|
||
if (OVS_LIKELY(miniflow_and_mask_matches_flow(&head->flow,
|
||
&subtable->mask,
|
||
flow))) {
|
||
/* Return highest priority rule that is visible. */
|
||
CLS_MATCH_FOR_EACH (rule, head) {
|
||
if (OVS_LIKELY(cls_match_visible_in_version(rule, version))) {
|
||
return rule;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
static const struct cls_match *
|
||
find_match_wc(const struct cls_subtable *subtable, ovs_version_t version,
|
||
const struct flow *flow, struct trie_ctx trie_ctx[CLS_MAX_TRIES],
|
||
unsigned int n_tries, struct flow_wildcards *wc)
|
||
{
|
||
if (OVS_UNLIKELY(!wc)) {
|
||
return find_match(subtable, version, flow,
|
||
flow_hash_in_minimask(flow, &subtable->mask, 0));
|
||
}
|
||
|
||
uint32_t basis = 0, hash;
|
||
const struct cls_match *rule = NULL;
|
||
struct flowmap stages_map = FLOWMAP_EMPTY_INITIALIZER;
|
||
unsigned int mask_offset = 0;
|
||
int i;
|
||
|
||
/* Try to finish early by checking fields in segments. */
|
||
for (i = 0; i < subtable->n_indices; i++) {
|
||
if (check_tries(trie_ctx, n_tries, subtable->trie_plen,
|
||
subtable->index_maps[i], flow, wc)) {
|
||
/* 'wc' bits for the trie field set, now unwildcard the preceding
|
||
* bits used so far. */
|
||
goto no_match;
|
||
}
|
||
|
||
/* Accumulate the map used so far. */
|
||
stages_map = flowmap_or(stages_map, subtable->index_maps[i]);
|
||
|
||
hash = flow_hash_in_minimask_range(flow, &subtable->mask,
|
||
subtable->index_maps[i],
|
||
&mask_offset, &basis);
|
||
|
||
if (!ccmap_find(&subtable->indices[i], hash)) {
|
||
goto no_match;
|
||
}
|
||
}
|
||
/* Trie check for the final range. */
|
||
if (check_tries(trie_ctx, n_tries, subtable->trie_plen,
|
||
subtable->index_maps[i], flow, wc)) {
|
||
goto no_match;
|
||
}
|
||
hash = flow_hash_in_minimask_range(flow, &subtable->mask,
|
||
subtable->index_maps[i],
|
||
&mask_offset, &basis);
|
||
rule = find_match(subtable, version, flow, hash);
|
||
if (!rule && subtable->ports_mask_len) {
|
||
/* The final stage had ports, but there was no match. Instead of
|
||
* unwildcarding all the ports bits, use the ports trie to figure out a
|
||
* smaller set of 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);
|
||
|
||
goto no_match;
|
||
}
|
||
|
||
/* Must unwildcard all the fields, as they were looked at. */
|
||
flow_wildcards_fold_minimask(wc, &subtable->mask);
|
||
return rule;
|
||
|
||
no_match:
|
||
/* Unwildcard the bits in stages so far, as they were used in determining
|
||
* there is no match. */
|
||
flow_wildcards_fold_minimask_in_map(wc, &subtable->mask, stages_map);
|
||
return NULL;
|
||
}
|
||
|
||
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 trie_prefix *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, NULL)) {
|
||
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)
|
||
{
|
||
size_t u64_ofs = mf->flow_be32ofs / 2;
|
||
|
||
return (OVS_FORCE const ovs_be32 *)miniflow_get__(match->flow, u64_ofs)
|
||
+ (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 trie_prefix) * CHAR_BIT];
|
||
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. */
|
||
}
|
||
|
||
|
||
#define CLS_MATCH_POISON (struct cls_match *)(UINTPTR_MAX / 0xf * 0xb)
|
||
|
||
void
|
||
cls_match_free_cb(struct cls_match *rule)
|
||
{
|
||
ovsrcu_set_hidden(&rule->next, CLS_MATCH_POISON);
|
||
free(rule);
|
||
}
|