/* * Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include #include "classifier.h" #include "classifier-private.h" #include #include #include "byte-order.h" #include "dynamic-string.h" #include "odp-util.h" #include "ofp-util.h" #include "packets.h" #include "util.h" #include "openvswitch/vlog.h" VLOG_DEFINE_THIS_MODULE(classifier); struct trie_ctx; /* A collection of "struct cls_conjunction"s currently embedded into a * cls_match. */ struct cls_conjunction_set { /* Link back to the cls_match. * * cls_conjunction_set is mostly used during classifier lookup, and, in * turn, during classifier lookup the most used member of * cls_conjunction_set is the rule's priority, so we cache it here for fast * access. */ struct cls_match *match; int priority; /* Cached copy of match->priority. */ /* Conjunction information. * * 'min_n_clauses' allows some optimization during classifier lookup. */ unsigned int n; /* Number of elements in 'conj'. */ unsigned int min_n_clauses; /* Smallest 'n' among elements of 'conj'. */ struct cls_conjunction conj[]; }; /* Ports trie depends on both ports sharing the same ovs_be32. */ #define TP_PORTS_OFS32 (offsetof(struct flow, tp_src) / 4) BUILD_ASSERT_DECL(TP_PORTS_OFS32 == offsetof(struct flow, tp_dst) / 4); BUILD_ASSERT_DECL(TP_PORTS_OFS32 % 2 == 0); #define TP_PORTS_OFS64 (TP_PORTS_OFS32 / 2) static size_t cls_conjunction_set_size(size_t n) { return (sizeof(struct cls_conjunction_set) + n * sizeof(struct cls_conjunction)); } static struct cls_conjunction_set * cls_conjunction_set_alloc(struct cls_match *match, const struct cls_conjunction conj[], size_t n) { if (n) { size_t min_n_clauses = conj[0].n_clauses; for (size_t i = 1; i < n; i++) { min_n_clauses = MIN(min_n_clauses, conj[i].n_clauses); } struct cls_conjunction_set *set = xmalloc(cls_conjunction_set_size(n)); set->match = match; set->priority = match->priority; set->n = n; set->min_n_clauses = min_n_clauses; memcpy(set->conj, conj, n * sizeof *conj); return set; } else { return NULL; } } static struct cls_match * cls_match_alloc(const struct cls_rule *rule, cls_version_t version, const struct cls_conjunction conj[], size_t n) { size_t count = miniflow_n_values(rule->match.flow); struct cls_match *cls_match = xmalloc(sizeof *cls_match + MINIFLOW_VALUES_SIZE(count)); ovsrcu_init(&cls_match->next, NULL); *CONST_CAST(const struct cls_rule **, &cls_match->cls_rule) = rule; *CONST_CAST(int *, &cls_match->priority) = rule->priority; *CONST_CAST(cls_version_t *, &cls_match->add_version) = version; atomic_init(&cls_match->remove_version, version); /* Initially * invisible. */ miniflow_clone(CONST_CAST(struct miniflow *, &cls_match->flow), rule->match.flow, count); ovsrcu_set_hidden(&cls_match->conj_set, cls_conjunction_set_alloc(cls_match, conj, n)); return cls_match; } static struct cls_subtable *find_subtable(const struct classifier *cls, const struct minimask *); static struct cls_subtable *insert_subtable(struct classifier *cls, const struct minimask *); static void destroy_subtable(struct classifier *cls, struct cls_subtable *); static const struct cls_match *find_match_wc(const struct cls_subtable *, cls_version_t version, const struct flow *, struct trie_ctx *, unsigned int n_tries, struct flow_wildcards *); static struct cls_match *find_equal(const struct cls_subtable *, const struct miniflow *, uint32_t hash); /* Return the next visible (lower-priority) rule in the list. Multiple * identical rules with the same priority may exist transitionally, but when * versioning is used at most one of them is ever visible for lookups on any * given 'version'. */ static inline const struct cls_match * next_visible_rule_in_list(const struct cls_match *rule, cls_version_t version) { do { rule = cls_match_next(rule); } while (rule && !cls_match_visible_in_version(rule, version)); return rule; } /* Type with maximum supported prefix length. */ union trie_prefix { struct in6_addr ipv6; /* For sizing. */ ovs_be32 be32; /* For access. */ }; static unsigned int minimask_get_prefix_len(const struct minimask *, const struct mf_field *); static void trie_init(struct classifier *cls, int trie_idx, const struct mf_field *); static unsigned int trie_lookup(const struct cls_trie *, const struct flow *, union trie_prefix *plens); static unsigned int trie_lookup_value(const rcu_trie_ptr *, const ovs_be32 value[], ovs_be32 plens[], unsigned int value_bits); static void trie_destroy(rcu_trie_ptr *); static void trie_insert(struct cls_trie *, const struct cls_rule *, int mlen); static void trie_insert_prefix(rcu_trie_ptr *, const ovs_be32 *prefix, int mlen); static void trie_remove(struct cls_trie *, const struct cls_rule *, int mlen); static void trie_remove_prefix(rcu_trie_ptr *, const ovs_be32 *prefix, int mlen); static void mask_set_prefix_bits(struct flow_wildcards *, uint8_t be32ofs, unsigned int n_bits); static bool mask_prefix_bits_set(const struct flow_wildcards *, uint8_t be32ofs, unsigned int n_bits); /* cls_rule. */ static inline void cls_rule_init__(struct cls_rule *rule, unsigned int priority) { rculist_init(&rule->node); *CONST_CAST(int *, &rule->priority) = priority; rule->cls_match = NULL; } /* Initializes 'rule' to match packets specified by 'match' at the given * 'priority'. 'match' must satisfy the invariant described in the comment at * the definition of struct match. * * The caller must eventually destroy 'rule' with cls_rule_destroy(). * * Clients should not use priority INT_MIN. (OpenFlow uses priorities between * 0 and UINT16_MAX, inclusive.) */ void cls_rule_init(struct cls_rule *rule, const struct match *match, int priority) { cls_rule_init__(rule, priority); minimatch_init(CONST_CAST(struct minimatch *, &rule->match), match); } /* Same as cls_rule_init() for initialization from a "struct minimatch". */ void cls_rule_init_from_minimatch(struct cls_rule *rule, const struct minimatch *match, int priority) { cls_rule_init__(rule, priority); minimatch_clone(CONST_CAST(struct minimatch *, &rule->match), match); } /* Initializes 'dst' as a copy of 'src'. * * The caller must eventually destroy 'dst' with cls_rule_destroy(). */ void cls_rule_clone(struct cls_rule *dst, const struct cls_rule *src) { cls_rule_init__(dst, src->priority); minimatch_clone(CONST_CAST(struct minimatch *, &dst->match), &src->match); } /* Initializes 'dst' with the data in 'src', destroying 'src'. * * 'src' must be a cls_rule NOT in a classifier. * * The caller must eventually destroy 'dst' with cls_rule_destroy(). */ void cls_rule_move(struct cls_rule *dst, struct cls_rule *src) { cls_rule_init__(dst, src->priority); minimatch_move(CONST_CAST(struct minimatch *, &dst->match), CONST_CAST(struct minimatch *, &src->match)); } /* Frees memory referenced by 'rule'. Doesn't free 'rule' itself (it's * normally embedded into a larger structure). * * ('rule' must not currently be in a classifier.) */ void cls_rule_destroy(struct cls_rule *rule) OVS_NO_THREAD_SAFETY_ANALYSIS { ovs_assert(!rule->cls_match); /* Must not be in a classifier. */ /* Check that the rule has been properly removed from the classifier. */ ovs_assert(rule->node.prev == RCULIST_POISON || rculist_is_empty(&rule->node)); rculist_poison__(&rule->node); /* Poisons also the next pointer. */ minimatch_destroy(CONST_CAST(struct minimatch *, &rule->match)); } void cls_rule_set_conjunctions(struct cls_rule *cr, const struct cls_conjunction *conj, size_t n) { struct cls_match *match = cr->cls_match; struct cls_conjunction_set *old = ovsrcu_get_protected(struct cls_conjunction_set *, &match->conj_set); struct cls_conjunction *old_conj = old ? old->conj : NULL; unsigned int old_n = old ? old->n : 0; if (old_n != n || (n && memcmp(old_conj, conj, n * sizeof *conj))) { if (old) { ovsrcu_postpone(free, old); } ovsrcu_set(&match->conj_set, cls_conjunction_set_alloc(match, conj, n)); } } /* Returns true if 'a' and 'b' match the same packets at the same priority, * false if they differ in some way. */ bool cls_rule_equal(const struct cls_rule *a, const struct cls_rule *b) { return a->priority == b->priority && minimatch_equal(&a->match, &b->match); } /* Appends a string describing 'rule' to 's'. */ void cls_rule_format(const struct cls_rule *rule, struct ds *s) { minimatch_format(&rule->match, s, rule->priority); } /* Returns true if 'rule' matches every packet, false otherwise. */ bool cls_rule_is_catchall(const struct cls_rule *rule) { return minimask_is_catchall(rule->match.mask); } /* Makes 'rule' invisible in 'remove_version'. Once that version is used in * lookups, the caller should remove 'rule' via ovsrcu_postpone(). * * 'rule' must be in a classifier. */ void cls_rule_make_invisible_in_version(const struct cls_rule *rule, cls_version_t remove_version) { ovs_assert(remove_version >= rule->cls_match->add_version); cls_match_set_remove_version(rule->cls_match, remove_version); } /* This undoes the change made by cls_rule_make_invisible_in_version(). * * 'rule' must be in a classifier. */ void cls_rule_restore_visibility(const struct cls_rule *rule) { cls_match_set_remove_version(rule->cls_match, CLS_NOT_REMOVED_VERSION); } /* Return true if 'rule' is visible in 'version'. * * 'rule' must be in a classifier. */ bool cls_rule_visible_in_version(const struct cls_rule *rule, cls_version_t version) { return cls_match_visible_in_version(rule->cls_match, version); } /* Initializes 'cls' as a classifier that initially contains no classification * rules. */ void classifier_init(struct classifier *cls, const uint8_t *flow_segments) { cls->n_rules = 0; cmap_init(&cls->subtables_map); pvector_init(&cls->subtables); cls->n_flow_segments = 0; if (flow_segments) { while (cls->n_flow_segments < CLS_MAX_INDICES && *flow_segments < FLOW_U64S) { cls->flow_segments[cls->n_flow_segments++] = *flow_segments++; } } cls->n_tries = 0; for (int i = 0; i < CLS_MAX_TRIES; i++) { trie_init(cls, i, NULL); } cls->publish = true; } /* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the * caller's responsibility. * May only be called after all the readers have been terminated. */ void classifier_destroy(struct classifier *cls) { if (cls) { struct cls_subtable *subtable; int i; for (i = 0; i < cls->n_tries; i++) { trie_destroy(&cls->tries[i].root); } CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) { destroy_subtable(cls, subtable); } cmap_destroy(&cls->subtables_map); pvector_destroy(&cls->subtables); } } /* Set the fields for which prefix lookup should be performed. */ bool classifier_set_prefix_fields(struct classifier *cls, const enum mf_field_id *trie_fields, unsigned int n_fields) { const struct mf_field * new_fields[CLS_MAX_TRIES]; struct mf_bitmap fields = MF_BITMAP_INITIALIZER; int i, n_tries = 0; bool changed = false; for (i = 0; i < n_fields && n_tries < CLS_MAX_TRIES; i++) { const struct mf_field *field = mf_from_id(trie_fields[i]); if (field->flow_be32ofs < 0 || field->n_bits % 32) { /* Incompatible field. This is the only place where we * enforce these requirements, but the rest of the trie code * depends on the flow_be32ofs to be non-negative and the * field length to be a multiple of 32 bits. */ continue; } if (bitmap_is_set(fields.bm, trie_fields[i])) { /* Duplicate field, there is no need to build more than * one index for any one field. */ continue; } bitmap_set1(fields.bm, trie_fields[i]); new_fields[n_tries] = NULL; if (n_tries >= cls->n_tries || field != cls->tries[n_tries].field) { new_fields[n_tries] = field; changed = true; } n_tries++; } if (changed || n_tries < cls->n_tries) { struct cls_subtable *subtable; /* Trie configuration needs to change. Disable trie lookups * for the tries that are changing and wait all the current readers * with the old configuration to be done. */ changed = false; CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) { for (i = 0; i < cls->n_tries; i++) { if ((i < n_tries && new_fields[i]) || i >= n_tries) { if (subtable->trie_plen[i]) { subtable->trie_plen[i] = 0; changed = true; } } } } /* Synchronize if any readers were using tries. The readers may * temporarily function without the trie lookup based optimizations. */ if (changed) { /* ovsrcu_synchronize() functions as a memory barrier, so it does * not matter that subtable->trie_plen is not atomic. */ ovsrcu_synchronize(); } /* Now set up the tries. */ for (i = 0; i < n_tries; i++) { if (new_fields[i]) { trie_init(cls, i, new_fields[i]); } } /* Destroy the rest, if any. */ for (; i < cls->n_tries; i++) { trie_init(cls, i, NULL); } cls->n_tries = n_tries; return true; } return false; /* No change. */ } static void trie_init(struct classifier *cls, int trie_idx, const struct mf_field *field) { struct cls_trie *trie = &cls->tries[trie_idx]; struct cls_subtable *subtable; if (trie_idx < cls->n_tries) { trie_destroy(&trie->root); } else { ovsrcu_set_hidden(&trie->root, NULL); } trie->field = field; /* Add existing rules to the new trie. */ CMAP_FOR_EACH (subtable, cmap_node, &cls->subtables_map) { unsigned int plen; plen = field ? minimask_get_prefix_len(&subtable->mask, field) : 0; if (plen) { struct cls_match *head; CMAP_FOR_EACH (head, cmap_node, &subtable->rules) { trie_insert(trie, head->cls_rule, plen); } } /* Initialize subtable's prefix length on this field. This will * allow readers to use the trie. */ atomic_thread_fence(memory_order_release); subtable->trie_plen[trie_idx] = plen; } } /* Returns true if 'cls' contains no classification rules, false otherwise. * Checking the cmap requires no locking. */ bool classifier_is_empty(const struct classifier *cls) { return cmap_is_empty(&cls->subtables_map); } /* Returns the number of rules in 'cls'. */ int classifier_count(const struct classifier *cls) { /* n_rules is an int, so in the presence of concurrent writers this will * return either the old or a new value. */ return cls->n_rules; } static inline ovs_be32 minimatch_get_ports(const struct minimatch *match) { /* Could optimize to use the same map if needed for fast path. */ return MINIFLOW_GET_BE32(match->flow, tp_src) & MINIFLOW_GET_BE32(&match->mask->masks, tp_src); } static void subtable_replace_head_rule(struct classifier *cls OVS_UNUSED, struct cls_subtable *subtable, struct cls_match *head, struct cls_match *new, uint32_t hash, uint32_t ihash[CLS_MAX_INDICES]) { /* Rule's data is already in the tries. */ for (int i = 0; i < subtable->n_indices; i++) { cmap_replace(&subtable->indices[i], &head->index_nodes[i], &new->index_nodes[i], ihash[i]); } cmap_replace(&subtable->rules, &head->cmap_node, &new->cmap_node, hash); } /* Inserts 'rule' into 'cls' 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, cls_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); 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. * * Readers may find the rule in the indices before the rule is visible * in the subtables 'rules' map. This may result in us losing the * opportunity to quit lookups earlier, resulting in sub-optimal * wildcarding. This will be fixed later by revalidation (always * scheduled after flow table changes). */ for (i = 0; i < subtable->n_indices; i++) { cmap_insert(&subtable->indices[i], &new->index_nodes[i], ihash[i]); } n_rules = cmap_insert(&subtable->rules, &new->cmap_node, hash); } else { /* Equal rules exist in the classifier already. */ struct cls_match *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) { subtable_replace_head_rule(cls, subtable, head, new, hash, ihash); } if (old) { struct cls_conjunction_set *conj_set; conj_set = ovsrcu_get_protected(struct cls_conjunction_set *, &iter->conj_set); if (conj_set) { ovsrcu_postpone(free, conj_set); } ovsrcu_postpone(cls_match_free_cb, iter); old->cls_match = NULL; /* 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, CLS_NOT_REMOVED_VERSION); /* 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, CLS_NOT_REMOVED_VERSION); /* 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, cls_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 = cls_rule->cls_match; if (!rule) { return NULL; } /* Mark as removed. */ 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) { subtable_replace_head_rule(cls, subtable, rule, next, hash, ihash); goto check_priority; } /* 'rule' is last of the kind in the classifier, must remove from all the * data structures. */ if (subtable->ports_mask_len) { ovs_be32 masked_ports = minimatch_get_ports(&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++) { cmap_remove(&subtable->indices[i], &rule->index_nodes[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; struct cls_match *head; 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, cls_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, 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, cls_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, cls_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, cls_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, cls_version_t version) { struct cls_subtable *subtable; /* Iterate subtables in the descending max priority order. */ PVECTOR_FOR_EACH_PRIORITY (subtable, target->priority - 1, 2, sizeof(struct cls_subtable), &cls->subtables) { 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_match_visible_in_version(rule->cls_match, 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, cls_version_t version) { /* Rule may only match a target if it is visible in target's version. */ return cls_match_visible_in_version(rule->cls_match, 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, cls_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)) { cmap_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, * and remove the last index if it doesn't. */ if (index > 0) { if (flowmap_equal(subtable->index_maps[index], subtable->index_maps[index - 1])) { --index; cmap_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++) { cmap_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, cls_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; } /* Returns true if 'target' satisifies 'flow'/'mask', that is, if each bit * for which 'flow', for which 'mask' has a bit set, specifies a particular * value has the correct value in 'target'. * * This function is equivalent to miniflow_and_mask_matches_flow() but this * version fills in the mask bits in 'wc'. */ static inline bool miniflow_and_mask_matches_flow_wc(const struct miniflow *flow, const struct minimask *mask, const struct flow *target, struct flow_wildcards *wc) { const uint64_t *flowp = miniflow_get_values(flow); const uint64_t *maskp = miniflow_get_values(&mask->masks); const uint64_t *target_u64 = (const uint64_t *)target; uint64_t *wc_u64 = (uint64_t *)&wc->masks; uint64_t diff; size_t idx; map_t map; FLOWMAP_FOR_EACH_MAP (map, mask->masks.map) { MAP_FOR_EACH_INDEX(idx, map) { uint64_t msk = *maskp++; diff = (*flowp++ ^ target_u64[idx]) & msk; if (diff) { goto out; } /* Fill in the bits that were looked at. */ wc_u64[idx] |= msk; } target_u64 += MAP_T_BITS; wc_u64 += MAP_T_BITS; } return true; out: /* Only unwildcard if none of the differing bits is already * exact-matched. */ if (!(wc_u64[idx] & diff)) { /* Keep one bit of the difference. The selected bit may be * different in big-endian v.s. little-endian systems. */ wc_u64[idx] |= rightmost_1bit(diff); } return false; } static const struct cls_match * find_match_wc(const struct cls_subtable *subtable, cls_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++) { const struct cmap_node *inode; 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); inode = cmap_find(&subtable->indices[i], hash); if (!inode) { goto no_match; } /* If we have narrowed down to a single rule already, check whether * that rule matches. Either way, we're done. * * (Rare) hash collisions may cause us to miss the opportunity for this * optimization. */ if (!cmap_node_next(inode)) { const struct cls_match *head; ASSIGN_CONTAINER(head, inode - i, index_nodes); if (miniflow_and_mask_matches_flow_wc(&head->flow, &subtable->mask, flow, wc)) { /* 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; } } /* 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)) { 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. */ VLOG_WARN("Trying to remove non-existing rule from a prefix trie."); } #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); }