/* * Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * 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 #include #include "byte-order.h" #include "dynamic-string.h" #include "flow.h" #include "hash.h" #include "odp-util.h" #include "ofp-util.h" #include "ovs-thread.h" #include "packets.h" #include "vlog.h" VLOG_DEFINE_THIS_MODULE(classifier); struct trie_node; struct trie_ctx; /* 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); /* Prefix trie for a 'field' */ struct cls_trie { const struct mf_field *field; /* Trie field, or NULL. */ struct trie_node *root; /* NULL if none. */ }; struct cls_subtable_entry { struct cls_subtable *subtable; tag_type tag; unsigned int max_priority; }; struct cls_subtable_cache { struct cls_subtable_entry *subtables; size_t alloc_size; /* Number of allocated elements. */ size_t size; /* One past last valid array element. */ }; enum { CLS_MAX_INDICES = 3 /* Maximum number of lookup indices per subtable. */ }; struct cls_classifier { int n_rules; /* Total number of rules. */ uint8_t n_flow_segments; uint8_t flow_segments[CLS_MAX_INDICES]; /* Flow segment boundaries to use * for staged lookup. */ struct hmap subtables; /* Contains "struct cls_subtable"s. */ struct cls_subtable_cache subtables_priority; struct hmap partitions; /* Contains "struct cls_partition"s. */ struct cls_trie tries[CLS_MAX_TRIES]; /* Prefix tries. */ unsigned int n_tries; }; /* A set of rules that all have the same fields wildcarded. */ struct cls_subtable { struct hmap_node hmap_node; /* Within struct cls_classifier 'subtables' * hmap. */ struct hmap rules; /* Contains "struct cls_rule"s. */ int n_rules; /* Number of rules, including duplicates. */ unsigned int max_priority; /* Max priority of any rule in the subtable. */ unsigned int max_count; /* Count of max_priority rules. */ tag_type tag; /* Tag generated from mask for partitioning. */ uint8_t n_indices; /* How many indices to use. */ uint8_t index_ofs[CLS_MAX_INDICES]; /* u32 flow segment boundaries. */ struct hindex indices[CLS_MAX_INDICES]; /* Staged lookup indices. */ unsigned int trie_plen[CLS_MAX_TRIES]; /* Trie prefix length in 'mask'. */ int ports_mask_len; struct trie_node *ports_trie; /* NULL if none. */ struct minimask mask; /* Wildcards for fields. */ /* 'mask' must be the last field. */ }; /* Associates a metadata value (that is, a value of the OpenFlow 1.1+ metadata * field) with tags for the "cls_subtable"s that contain rules that match that * metadata value. */ struct cls_partition { struct hmap_node hmap_node; /* In struct cls_classifier's 'partitions' * hmap. */ ovs_be64 metadata; /* metadata value for this partition. */ tag_type tags; /* OR of each flow's cls_subtable tag. */ struct tag_tracker tracker; /* Tracks the bits in 'tags'. */ }; /* Internal representation of a rule in a "struct cls_subtable". */ struct cls_match { struct cls_rule *cls_rule; struct hindex_node index_nodes[CLS_MAX_INDICES]; /* Within subtable's * 'indices'. */ struct hmap_node hmap_node; /* Within struct cls_subtable 'rules'. */ unsigned int priority; /* Larger numbers are higher priorities. */ struct cls_partition *partition; struct list list; /* List of identical, lower-priority rules. */ struct miniflow flow; /* Matching rule. Mask is in the subtable. */ /* 'flow' must be the last field. */ }; static struct cls_match * cls_match_alloc(struct cls_rule *rule) { int count = count_1bits(rule->match.flow.map); struct cls_match *cls_match = xmalloc(sizeof *cls_match - sizeof cls_match->flow.inline_values + MINIFLOW_VALUES_SIZE(count)); cls_match->cls_rule = rule; miniflow_clone_inline(&cls_match->flow, &rule->match.flow, count); cls_match->priority = rule->priority; rule->cls_match = cls_match; return cls_match; } static struct cls_subtable *find_subtable(const struct cls_classifier *, const struct minimask *); static struct cls_subtable *insert_subtable(struct cls_classifier *, const struct minimask *); static void destroy_subtable(struct cls_classifier *, struct cls_subtable *); static void update_subtables_after_insertion(struct cls_classifier *, struct cls_subtable *, unsigned int new_priority); static void update_subtables_after_removal(struct cls_classifier *, struct cls_subtable *, unsigned int del_priority); static struct cls_match *find_match_wc(const struct cls_subtable *, const struct flow *, struct trie_ctx *, unsigned int n_tries, struct flow_wildcards *); static struct cls_match *find_equal(struct cls_subtable *, const struct miniflow *, uint32_t hash); static struct cls_match *insert_rule(struct cls_classifier *, struct cls_subtable *, struct cls_rule *); /* Iterates RULE over HEAD and all of the cls_rules on HEAD->list. */ #define FOR_EACH_RULE_IN_LIST(RULE, HEAD) \ for ((RULE) = (HEAD); (RULE) != NULL; (RULE) = next_rule_in_list(RULE)) #define FOR_EACH_RULE_IN_LIST_SAFE(RULE, NEXT, HEAD) \ for ((RULE) = (HEAD); \ (RULE) != NULL && ((NEXT) = next_rule_in_list(RULE), true); \ (RULE) = (NEXT)) static struct cls_match *next_rule_in_list__(struct cls_match *); static struct cls_match *next_rule_in_list(struct cls_match *); static unsigned int minimask_get_prefix_len(const struct minimask *, const struct mf_field *); static void trie_init(struct cls_classifier *, int trie_idx, const struct mf_field *); static unsigned int trie_lookup(const struct cls_trie *, const struct flow *, unsigned int *checkbits); static unsigned int trie_lookup_value(const struct trie_node *, const ovs_be32 value[], unsigned int *checkbits); static void trie_destroy(struct trie_node *); static void trie_insert(struct cls_trie *, const struct cls_rule *, int mlen); static void trie_insert_prefix(struct trie_node **, const ovs_be32 *prefix, int mlen); static void trie_remove(struct cls_trie *, const struct cls_rule *, int mlen); static void trie_remove_prefix(struct trie_node **, const ovs_be32 *prefix, int mlen); static void mask_set_prefix_bits(struct flow_wildcards *, uint8_t be32ofs, unsigned int nbits); static bool mask_prefix_bits_set(const struct flow_wildcards *, uint8_t be32ofs, unsigned int nbits); static void cls_subtable_cache_init(struct cls_subtable_cache *array) { memset(array, 0, sizeof *array); } static void cls_subtable_cache_destroy(struct cls_subtable_cache *array) { free(array->subtables); memset(array, 0, sizeof *array); } /* Array insertion. */ static void cls_subtable_cache_push_back(struct cls_subtable_cache *array, struct cls_subtable_entry a) { if (array->size == array->alloc_size) { array->subtables = x2nrealloc(array->subtables, &array->alloc_size, sizeof a); } array->subtables[array->size++] = a; } /* Only for rearranging entries in the same cache. */ static inline void cls_subtable_cache_splice(struct cls_subtable_entry *to, struct cls_subtable_entry *start, struct cls_subtable_entry *end) { if (to > end) { /* Same as splicing entries to (start) from [end, to). */ struct cls_subtable_entry *temp = to; to = start; start = end; end = temp; } if (to < start) { while (start != end) { struct cls_subtable_entry temp = *start; memmove(to + 1, to, (start - to) * sizeof *to); *to = temp; start++; } } /* Else nothing to be done. */ } /* Array removal. */ static inline void cls_subtable_cache_remove(struct cls_subtable_cache *array, struct cls_subtable_entry *elem) { ssize_t size = (&array->subtables[array->size] - (elem + 1)) * sizeof *elem; if (size > 0) { memmove(elem, elem + 1, size); } array->size--; } #define CLS_SUBTABLE_CACHE_FOR_EACH(SUBTABLE, ITER, ARRAY) \ for (ITER = (ARRAY)->subtables; \ ITER < &(ARRAY)->subtables[(ARRAY)->size] \ && OVS_LIKELY(SUBTABLE = ITER->subtable); \ ++ITER) #define CLS_SUBTABLE_CACHE_FOR_EACH_CONTINUE(SUBTABLE, ITER, ARRAY) \ for (++ITER; \ ITER < &(ARRAY)->subtables[(ARRAY)->size] \ && OVS_LIKELY(SUBTABLE = ITER->subtable); \ ++ITER) #define CLS_SUBTABLE_CACHE_FOR_EACH_REVERSE(SUBTABLE, ITER, ARRAY) \ for (ITER = &(ARRAY)->subtables[(ARRAY)->size]; \ ITER > (ARRAY)->subtables \ && OVS_LIKELY(SUBTABLE = (--ITER)->subtable);) /* flow/miniflow/minimask/minimatch utilities. * These are only used by the classifier, so place them here to allow * for better optimization. */ static inline uint64_t miniflow_get_map_in_range(const struct miniflow *miniflow, uint8_t start, uint8_t end, unsigned int *offset) { uint64_t map = miniflow->map; *offset = 0; if (start > 0) { uint64_t msk = (UINT64_C(1) << start) - 1; /* 'start' LSBs set */ *offset = count_1bits(map & msk); map &= ~msk; } if (end < FLOW_U32S) { uint64_t msk = (UINT64_C(1) << end) - 1; /* 'end' LSBs set */ map &= msk; } return map; } /* Returns a hash value for the bits of 'flow' where there are 1-bits in * 'mask', given 'basis'. * * The hash values returned by this function are the same as those returned by * miniflow_hash_in_minimask(), only the form of the arguments differ. */ static inline uint32_t flow_hash_in_minimask(const struct flow *flow, const struct minimask *mask, uint32_t basis) { const uint32_t *mask_values = miniflow_get_u32_values(&mask->masks); const uint32_t *flow_u32 = (const uint32_t *)flow; const uint32_t *p = mask_values; uint32_t hash; uint64_t map; hash = basis; for (map = mask->masks.map; map; map = zero_rightmost_1bit(map)) { hash = mhash_add(hash, flow_u32[raw_ctz(map)] & *p++); } return mhash_finish(hash, (p - mask_values) * 4); } /* Returns a hash value for the bits of 'flow' where there are 1-bits in * 'mask', given 'basis'. * * The hash values returned by this function are the same as those returned by * flow_hash_in_minimask(), only the form of the arguments differ. */ static inline uint32_t miniflow_hash_in_minimask(const struct miniflow *flow, const struct minimask *mask, uint32_t basis) { const uint32_t *mask_values = miniflow_get_u32_values(&mask->masks); const uint32_t *p = mask_values; uint32_t hash = basis; uint32_t flow_u32; MINIFLOW_FOR_EACH_IN_MAP(flow_u32, flow, mask->masks.map) { hash = mhash_add(hash, flow_u32 & *p++); } return mhash_finish(hash, (p - mask_values) * 4); } /* Returns a hash value for the bits of range [start, end) in 'flow', * where there are 1-bits in 'mask', given 'hash'. * * The hash values returned by this function are the same as those returned by * minimatch_hash_range(), only the form of the arguments differ. */ static inline uint32_t flow_hash_in_minimask_range(const struct flow *flow, const struct minimask *mask, uint8_t start, uint8_t end, uint32_t *basis) { const uint32_t *mask_values = miniflow_get_u32_values(&mask->masks); const uint32_t *flow_u32 = (const uint32_t *)flow; unsigned int offset; uint64_t map = miniflow_get_map_in_range(&mask->masks, start, end, &offset); const uint32_t *p = mask_values + offset; uint32_t hash = *basis; for (; map; map = zero_rightmost_1bit(map)) { hash = mhash_add(hash, flow_u32[raw_ctz(map)] & *p++); } *basis = hash; /* Allow continuation from the unfinished value. */ return mhash_finish(hash, (p - mask_values) * 4); } /* Fold minimask 'mask''s wildcard mask into 'wc's wildcard mask. */ static inline void flow_wildcards_fold_minimask(struct flow_wildcards *wc, const struct minimask *mask) { flow_union_with_miniflow(&wc->masks, &mask->masks); } /* Fold minimask 'mask''s wildcard mask into 'wc's wildcard mask * in range [start, end). */ static inline void flow_wildcards_fold_minimask_range(struct flow_wildcards *wc, const struct minimask *mask, uint8_t start, uint8_t end) { uint32_t *dst_u32 = (uint32_t *)&wc->masks; unsigned int offset; uint64_t map = miniflow_get_map_in_range(&mask->masks, start, end, &offset); const uint32_t *p = miniflow_get_u32_values(&mask->masks) + offset; for (; map; map = zero_rightmost_1bit(map)) { dst_u32[raw_ctz(map)] |= *p++; } } /* Returns a hash value for 'flow', given 'basis'. */ static inline uint32_t miniflow_hash(const struct miniflow *flow, uint32_t basis) { const uint32_t *values = miniflow_get_u32_values(flow); const uint32_t *p = values; uint32_t hash = basis; uint64_t hash_map = 0; uint64_t map; for (map = flow->map; map; map = zero_rightmost_1bit(map)) { if (*p) { hash = mhash_add(hash, *p); hash_map |= rightmost_1bit(map); } p++; } hash = mhash_add(hash, hash_map); hash = mhash_add(hash, hash_map >> 32); return mhash_finish(hash, p - values); } /* Returns a hash value for 'mask', given 'basis'. */ static inline uint32_t minimask_hash(const struct minimask *mask, uint32_t basis) { return miniflow_hash(&mask->masks, basis); } /* Returns a hash value for 'match', given 'basis'. */ static inline uint32_t minimatch_hash(const struct minimatch *match, uint32_t basis) { return miniflow_hash(&match->flow, minimask_hash(&match->mask, basis)); } /* Returns a hash value for the bits of range [start, end) in 'minimatch', * given 'basis'. * * The hash values returned by this function are the same as those returned by * flow_hash_in_minimask_range(), only the form of the arguments differ. */ static inline uint32_t minimatch_hash_range(const struct minimatch *match, uint8_t start, uint8_t end, uint32_t *basis) { unsigned int offset; const uint32_t *p, *q; uint32_t hash = *basis; int n, i; n = count_1bits(miniflow_get_map_in_range(&match->mask.masks, start, end, &offset)); q = miniflow_get_u32_values(&match->mask.masks) + offset; p = miniflow_get_u32_values(&match->flow) + offset; for (i = 0; i < n; i++) { hash = mhash_add(hash, p[i] & q[i]); } *basis = hash; /* Allow continuation from the unfinished value. */ return mhash_finish(hash, (offset + n) * 4); } /* cls_rule. */ /* Initializes 'rule' to match packets specified by 'match' at the given * 'priority'. 'match' must satisfy the invariant described in the comment at * the definition of struct match. * * The caller must eventually destroy 'rule' with cls_rule_destroy(). * * (OpenFlow uses priorities between 0 and UINT16_MAX, inclusive, but * internally Open vSwitch supports a wider range.) */ void cls_rule_init(struct cls_rule *rule, const struct match *match, unsigned int priority) { minimatch_init(&rule->match, match); rule->priority = priority; rule->cls_match = NULL; } /* 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, unsigned int priority) { minimatch_clone(&rule->match, match); rule->priority = priority; rule->cls_match = NULL; } /* 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) { minimatch_clone(&dst->match, &src->match); dst->priority = src->priority; dst->cls_match = NULL; } /* Initializes 'dst' with the data in 'src', destroying 'src'. * * The caller must eventually destroy 'dst' with cls_rule_destroy(). */ void cls_rule_move(struct cls_rule *dst, struct cls_rule *src) { minimatch_move(&dst->match, &src->match); dst->priority = src->priority; dst->cls_match = NULL; } /* Frees memory referenced by 'rule'. Doesn't free 'rule' itself (it's * normally embedded into a larger structure). * * ('rule' must not currently be in a classifier.) */ void cls_rule_destroy(struct cls_rule *rule) { ovs_assert(!rule->cls_match); minimatch_destroy(&rule->match); } /* Returns true if 'a' and 'b' match the same packets at the same priority, * false if they differ in some way. */ bool cls_rule_equal(const struct cls_rule *a, const struct cls_rule *b) { return a->priority == b->priority && minimatch_equal(&a->match, &b->match); } /* Returns a hash value for 'rule', folding in 'basis'. */ uint32_t cls_rule_hash(const struct cls_rule *rule, uint32_t basis) { return minimatch_hash(&rule->match, hash_int(rule->priority, basis)); } /* Appends a string describing 'rule' to 's'. */ void cls_rule_format(const struct cls_rule *rule, struct ds *s) { minimatch_format(&rule->match, s, rule->priority); } /* Returns true if 'rule' matches every packet, false otherwise. */ bool cls_rule_is_catchall(const struct cls_rule *rule) { return minimask_is_catchall(&rule->match.mask); } /* Initializes 'cls' as a classifier that initially contains no classification * rules. */ void classifier_init(struct classifier *cls_, const uint8_t *flow_segments) { struct cls_classifier *cls = xmalloc(sizeof *cls); fat_rwlock_init(&cls_->rwlock); cls_->cls = cls; cls->n_rules = 0; hmap_init(&cls->subtables); cls_subtable_cache_init(&cls->subtables_priority); hmap_init(&cls->partitions); cls->n_flow_segments = 0; if (flow_segments) { while (cls->n_flow_segments < CLS_MAX_INDICES && *flow_segments < FLOW_U32S) { cls->flow_segments[cls->n_flow_segments++] = *flow_segments++; } } cls->n_tries = 0; } /* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the * caller's responsibility. */ void classifier_destroy(struct classifier *cls_) { if (cls_) { struct cls_classifier *cls = cls_->cls; struct cls_subtable *partition, *next_partition; struct cls_subtable *subtable, *next_subtable; int i; fat_rwlock_destroy(&cls_->rwlock); if (!cls) { return; } for (i = 0; i < cls->n_tries; i++) { trie_destroy(cls->tries[i].root); } HMAP_FOR_EACH_SAFE (subtable, next_subtable, hmap_node, &cls->subtables) { destroy_subtable(cls, subtable); } hmap_destroy(&cls->subtables); HMAP_FOR_EACH_SAFE (partition, next_partition, hmap_node, &cls->partitions) { hmap_remove(&cls->partitions, &partition->hmap_node); free(partition); } hmap_destroy(&cls->partitions); cls_subtable_cache_destroy(&cls->subtables_priority); free(cls); } } /* We use uint64_t as a set for the fields below. */ BUILD_ASSERT_DECL(MFF_N_IDS <= 64); /* Set the fields for which prefix lookup should be performed. */ void classifier_set_prefix_fields(struct classifier *cls_, const enum mf_field_id *trie_fields, unsigned int n_fields) { struct cls_classifier *cls = cls_->cls; uint64_t fields = 0; int i, trie; for (i = 0, trie = 0; i < n_fields && trie < CLS_MAX_TRIES; i++) { const struct mf_field *field = mf_from_id(trie_fields[i]); if (field->flow_be32ofs < 0 || field->n_bits % 32) { /* Incompatible field. This is the only place where we * enforce these requirements, but the rest of the trie code * depends on the flow_be32ofs to be non-negative and the * field length to be a multiple of 32 bits. */ continue; } if (fields & (UINT64_C(1) << trie_fields[i])) { /* Duplicate field, there is no need to build more than * one index for any one field. */ continue; } fields |= UINT64_C(1) << trie_fields[i]; if (trie >= cls->n_tries || field != cls->tries[trie].field) { trie_init(cls, trie, field); } trie++; } /* Destroy the rest. */ for (i = trie; i < cls->n_tries; i++) { trie_init(cls, i, NULL); } cls->n_tries = trie; } static void trie_init(struct cls_classifier *cls, int trie_idx, const struct mf_field *field) { struct cls_trie *trie = &cls->tries[trie_idx]; struct cls_subtable *subtable; struct cls_subtable_entry *iter; if (trie_idx < cls->n_tries) { trie_destroy(trie->root); } trie->root = NULL; trie->field = field; /* Add existing rules to the trie. */ CLS_SUBTABLE_CACHE_FOR_EACH (subtable, iter, &cls->subtables_priority) { unsigned int plen; plen = field ? minimask_get_prefix_len(&subtable->mask, field) : 0; /* Initialize subtable's prefix length on this field. */ subtable->trie_plen[trie_idx] = plen; if (plen) { struct cls_match *head; HMAP_FOR_EACH (head, hmap_node, &subtable->rules) { struct cls_match *match; FOR_EACH_RULE_IN_LIST (match, head) { trie_insert(trie, match->cls_rule, plen); } } } } } /* Returns true if 'cls' contains no classification rules, false otherwise. */ bool classifier_is_empty(const struct classifier *cls) { return cls->cls->n_rules == 0; } /* Returns the number of rules in 'cls'. */ int classifier_count(const struct classifier *cls) { return cls->cls->n_rules; } static uint32_t hash_metadata(ovs_be64 metadata_) { uint64_t metadata = (OVS_FORCE uint64_t) metadata_; return hash_uint64(metadata); } static struct cls_partition * find_partition(const struct cls_classifier *cls, ovs_be64 metadata, uint32_t hash) { struct cls_partition *partition; HMAP_FOR_EACH_IN_BUCKET (partition, hmap_node, hash, &cls->partitions) { if (partition->metadata == metadata) { return partition; } } return NULL; } static struct cls_partition * create_partition(struct cls_classifier *cls, struct cls_subtable *subtable, ovs_be64 metadata) { uint32_t hash = hash_metadata(metadata); struct cls_partition *partition = find_partition(cls, metadata, hash); if (!partition) { partition = xmalloc(sizeof *partition); partition->metadata = metadata; partition->tags = 0; tag_tracker_init(&partition->tracker); hmap_insert(&cls->partitions, &partition->hmap_node, hash); } tag_tracker_add(&partition->tracker, &partition->tags, subtable->tag); return partition; } static inline ovs_be32 minimatch_get_ports(const struct minimatch *match) { /* Could optimize to use the same map if needed for fast path. */ return MINIFLOW_GET_BE32(&match->flow, tp_src) & MINIFLOW_GET_BE32(&match->mask.masks, tp_src); } /* Inserts 'rule' into 'cls'. Until 'rule' is removed from 'cls', the caller * must not modify or free it. * * If 'cls' already contains an identical rule (including wildcards, values of * fixed fields, and priority), replaces the old rule by 'rule' and returns the * rule that was replaced. The caller takes ownership of the returned rule and * is thus responsible for destroying it with cls_rule_destroy(), freeing the * memory block in which it resides, etc., as necessary. * * Returns NULL if 'cls' does not contain a rule with an identical key, after * inserting the new rule. In this case, no rules are displaced by the new * rule, even rules that cannot have any effect because the new rule matches a * superset of their flows and has higher priority. */ struct cls_rule * classifier_replace(struct classifier *cls_, struct cls_rule *rule) { struct cls_classifier *cls = cls_->cls; struct cls_match *old_rule; struct cls_subtable *subtable; subtable = find_subtable(cls, &rule->match.mask); if (!subtable) { subtable = insert_subtable(cls, &rule->match.mask); } old_rule = insert_rule(cls, subtable, rule); if (!old_rule) { int i; rule->cls_match->partition = NULL; if (minimask_get_metadata_mask(&rule->match.mask) == OVS_BE64_MAX) { ovs_be64 metadata = miniflow_get_metadata(&rule->match.flow); rule->cls_match->partition = create_partition(cls, subtable, metadata); } subtable->n_rules++; cls->n_rules++; for (i = 0; i < cls->n_tries; i++) { if (subtable->trie_plen[i]) { trie_insert(&cls->tries[i], rule, subtable->trie_plen[i]); } } /* 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); } return NULL; } else { struct cls_rule *old_cls_rule = old_rule->cls_rule; rule->cls_match->partition = old_rule->partition; old_cls_rule->cls_match = NULL; free(old_rule); return old_cls_rule; } } /* 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, struct cls_rule *rule) { struct cls_rule *displaced_rule = classifier_replace(cls, rule); 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. */ void classifier_remove(struct classifier *cls_, struct cls_rule *rule) { struct cls_classifier *cls = cls_->cls; struct cls_partition *partition; struct cls_match *cls_match = rule->cls_match; struct cls_match *head; struct cls_subtable *subtable; int i; ovs_assert(cls_match); subtable = find_subtable(cls, &rule->match.mask); ovs_assert(subtable); if (subtable->ports_mask_len) { ovs_be32 masked_ports = minimatch_get_ports(&rule->match); trie_remove_prefix(&subtable->ports_trie, &masked_ports, subtable->ports_mask_len); } for (i = 0; i < cls->n_tries; i++) { if (subtable->trie_plen[i]) { trie_remove(&cls->tries[i], rule, subtable->trie_plen[i]); } } /* Remove rule node from indices. */ for (i = 0; i < subtable->n_indices; i++) { hindex_remove(&subtable->indices[i], &cls_match->index_nodes[i]); } head = find_equal(subtable, &rule->match.flow, cls_match->hmap_node.hash); if (head != cls_match) { list_remove(&cls_match->list); } else if (list_is_empty(&cls_match->list)) { hmap_remove(&subtable->rules, &cls_match->hmap_node); } else { struct cls_match *next = CONTAINER_OF(cls_match->list.next, struct cls_match, list); list_remove(&cls_match->list); hmap_replace(&subtable->rules, &cls_match->hmap_node, &next->hmap_node); } partition = cls_match->partition; if (partition) { tag_tracker_subtract(&partition->tracker, &partition->tags, subtable->tag); if (!partition->tags) { hmap_remove(&cls->partitions, &partition->hmap_node); free(partition); } } if (--subtable->n_rules == 0) { destroy_subtable(cls, subtable); } else { update_subtables_after_removal(cls, subtable, cls_match->priority); } cls->n_rules--; rule->cls_match = NULL; free(cls_match); } /* Prefix tree context. Valid when 'lookup_done' is true. Can skip all * subtables which have more than 'match_plen' bits in their corresponding * field at offset 'be32ofs'. If skipped, 'maskbits' prefix bits should be * unwildcarded to quarantee datapath flow matches only packets it should. */ struct trie_ctx { const struct cls_trie *trie; bool lookup_done; /* Status of the lookup. */ uint8_t be32ofs; /* U32 offset of the field in question. */ unsigned int match_plen; /* Longest prefix than could possibly match. */ unsigned int maskbits; /* Prefix length needed to avoid false matches. */ }; static void trie_ctx_init(struct trie_ctx *ctx, const struct cls_trie *trie) { ctx->trie = trie; ctx->be32ofs = trie->field->flow_be32ofs; ctx->lookup_done = false; } static inline void lookahead_subtable(const struct cls_subtable_entry *subtables) { ovs_prefetch_range(subtables->subtable, sizeof *subtables->subtable); } /* Finds and returns the highest-priority rule in 'cls' that matches 'flow'. * Returns a null pointer if no rules in 'cls' match 'flow'. If multiple rules * of equal priority match 'flow', returns one arbitrarily. * * If a rule is found and 'wc' is non-null, bitwise-OR's 'wc' with the * set of bits that were significant in the lookup. At some point * earlier, 'wc' should have been initialized (e.g., by * flow_wildcards_init_catchall()). */ struct cls_rule * classifier_lookup(const struct classifier *cls_, const struct flow *flow, struct flow_wildcards *wc) { struct cls_classifier *cls = cls_->cls; const struct cls_partition *partition; tag_type tags; struct cls_match *best; struct trie_ctx trie_ctx[CLS_MAX_TRIES]; int i; struct cls_subtable_entry *subtables = cls->subtables_priority.subtables; int n_subtables = cls->subtables_priority.size; int64_t best_priority = -1; /* Prefetch the subtables array. */ ovs_prefetch_range(subtables, n_subtables * sizeof *subtables); /* Determine 'tags' such that, if 'subtable->tag' doesn't intersect them, * then 'flow' cannot possibly match in 'subtable': * * - If flow->metadata maps to a given 'partition', then we can use * 'tags' for 'partition->tags'. * * - If flow->metadata has no partition, then no rule in 'cls' has an * exact-match for flow->metadata. That means that we don't need to * search any subtable that includes flow->metadata in its mask. * * In either case, we always need to search any cls_subtables that do not * include flow->metadata in its mask. One way to do that would be to * check the "cls_subtable"s explicitly for that, but that would require an * extra branch per subtable. Instead, we mark such a cls_subtable's * 'tags' as TAG_ALL and make sure that 'tags' is never empty. This means * that 'tags' always intersects such a cls_subtable's 'tags', so we don't * need a special case. */ partition = (hmap_is_empty(&cls->partitions) ? NULL : find_partition(cls, flow->metadata, hash_metadata(flow->metadata))); tags = partition ? partition->tags : TAG_ARBITRARY; /* Initialize trie contexts for match_find_wc(). */ for (i = 0; i < cls->n_tries; i++) { trie_ctx_init(&trie_ctx[i], &cls->tries[i]); } /* Prefetch the first subtables. */ if (n_subtables > 1) { lookahead_subtable(subtables); lookahead_subtable(subtables + 1); } best = NULL; for (i = 0; OVS_LIKELY(i < n_subtables); i++) { struct cls_match *rule; if ((int64_t)subtables[i].max_priority <= best_priority) { /* Subtables are in descending priority order, * can not find anything better. */ break; } /* Prefetch a forthcoming subtable. */ if (i + 2 < n_subtables) { lookahead_subtable(&subtables[i + 2]); } if (!tag_intersects(tags, subtables[i].tag)) { continue; } rule = find_match_wc(subtables[i].subtable, flow, trie_ctx, cls->n_tries, wc); if (rule && (int64_t)rule->priority > best_priority) { best_priority = (int64_t)rule->priority; best = rule; } } return best ? best->cls_rule : NULL; } /* Returns true if 'target' satisifies 'match', that is, if each bit for which * 'match' specifies a particular value has the correct value in 'target'. * * 'flow' and 'mask' have the same mask! */ static bool miniflow_and_mask_matches_miniflow(const struct miniflow *flow, const struct minimask *mask, const struct miniflow *target) { const uint32_t *flowp = miniflow_get_u32_values(flow); const uint32_t *maskp = miniflow_get_u32_values(&mask->masks); uint32_t target_u32; MINIFLOW_FOR_EACH_IN_MAP(target_u32, target, mask->masks.map) { if ((*flowp++ ^ target_u32) & *maskp++) { return false; } } return true; } static inline struct cls_match * find_match_miniflow(const struct cls_subtable *subtable, const struct miniflow *flow, uint32_t hash) { struct cls_match *rule; HMAP_FOR_EACH_WITH_HASH (rule, hmap_node, hash, &subtable->rules) { if (miniflow_and_mask_matches_miniflow(&rule->flow, &subtable->mask, flow)) { return rule; } } return NULL; } /* Finds and returns the highest-priority rule in 'cls' that matches * 'miniflow'. Returns a null pointer if no rules in 'cls' match 'flow'. * If multiple rules of equal priority match 'flow', returns one arbitrarily. * * This function is optimized for the userspace datapath, which only ever has * one priority value for it's flows! */ struct cls_rule *classifier_lookup_miniflow_first(const struct classifier *cls_, const struct miniflow *flow) { struct cls_classifier *cls = cls_->cls; struct cls_subtable *subtable; struct cls_subtable_entry *iter; CLS_SUBTABLE_CACHE_FOR_EACH (subtable, iter, &cls->subtables_priority) { struct cls_match *rule; rule = find_match_miniflow(subtable, flow, miniflow_hash_in_minimask(flow, &subtable->mask, 0)); if (rule) { return rule->cls_rule; } } return NULL; } /* Finds and returns a rule in 'cls' with exactly the same priority and * matching criteria as 'target'. Returns a null pointer if 'cls' doesn't * contain an exact match. */ struct cls_rule * classifier_find_rule_exactly(const struct classifier *cls_, const struct cls_rule *target) { struct cls_classifier *cls = cls_->cls; struct cls_match *head, *rule; struct cls_subtable *subtable; subtable = find_subtable(cls, &target->match.mask); if (!subtable) { return NULL; } /* Skip if there is no hope. */ if (target->priority > subtable->max_priority) { return NULL; } head = find_equal(subtable, &target->match.flow, miniflow_hash_in_minimask(&target->match.flow, &target->match.mask, 0)); FOR_EACH_RULE_IN_LIST (rule, head) { if (target->priority >= rule->priority) { return target->priority == rule->priority ? rule->cls_rule : NULL; } } return NULL; } /* Finds and returns a rule in 'cls' with priority 'priority' and exactly the * same matching criteria as 'target'. Returns a null pointer if 'cls' doesn't * contain an exact match. */ struct cls_rule * classifier_find_match_exactly(const struct classifier *cls, const struct match *target, unsigned int priority) { struct cls_rule *retval; struct cls_rule cr; cls_rule_init(&cr, target, priority); retval = classifier_find_rule_exactly(cls, &cr); cls_rule_destroy(&cr); return retval; } /* Checks if 'target' would overlap any other rule in 'cls'. Two rules are * considered to overlap if both rules have the same priority and a packet * could match both. */ bool classifier_rule_overlaps(const struct classifier *cls_, const struct cls_rule *target) { struct cls_classifier *cls = cls_->cls; struct cls_subtable *subtable; struct cls_subtable_entry *iter; /* Iterate subtables in the descending max priority order. */ CLS_SUBTABLE_CACHE_FOR_EACH (subtable, iter, &cls->subtables_priority) { uint32_t storage[FLOW_U32S]; struct minimask mask; struct cls_match *head; if (target->priority > iter->max_priority) { break; /* Can skip this and the rest of the subtables. */ } minimask_combine(&mask, &target->match.mask, &subtable->mask, storage); HMAP_FOR_EACH (head, hmap_node, &subtable->rules) { struct cls_match *rule; FOR_EACH_RULE_IN_LIST (rule, head) { if (rule->priority < target->priority) { break; /* Rules in descending priority order. */ } if (rule->priority == target->priority && miniflow_equal_in_minimask(&target->match.flow, &rule->flow, &mask)) { return true; } } } } return false; } /* Returns true if 'rule' exactly matches 'criteria' or if 'rule' is more * specific than 'criteria'. That is, 'rule' matches 'criteria' and this * function returns true if, for every field: * * - 'criteria' and 'rule' specify the same (non-wildcarded) value for the * field, or * * - 'criteria' wildcards the field, * * Conversely, 'rule' does not match 'criteria' and this function returns false * if, for at least one field: * * - 'criteria' and 'rule' specify different values for the field, or * * - 'criteria' specifies a value for the field but 'rule' wildcards it. * * Equivalently, the truth table for whether a field matches is: * * rule * * c wildcard exact * r +---------+---------+ * i wild | yes | yes | * t card | | | * e +---------+---------+ * r exact | no |if values| * i | |are equal| * a +---------+---------+ * * This is the matching rule used by OpenFlow 1.0 non-strict OFPT_FLOW_MOD * commands and by OpenFlow 1.0 aggregate and flow stats. * * Ignores rule->priority. */ bool cls_rule_is_loose_match(const struct cls_rule *rule, const struct minimatch *criteria) { return (!minimask_has_extra(&rule->match.mask, &criteria->mask) && miniflow_equal_in_minimask(&rule->match.flow, &criteria->flow, &criteria->mask)); } /* Iteration. */ static bool rule_matches(const struct cls_match *rule, const struct cls_rule *target) { return (!target || miniflow_equal_in_minimask(&rule->flow, &target->match.flow, &target->match.mask)); } static struct cls_match * search_subtable(const struct cls_subtable *subtable, const struct cls_rule *target) { if (!target || !minimask_has_extra(&subtable->mask, &target->match.mask)) { struct cls_match *rule; HMAP_FOR_EACH (rule, hmap_node, &subtable->rules) { if (rule_matches(rule, target)) { return rule; } } } return NULL; } /* Initializes 'cursor' for iterating through rules in 'cls': * * - If 'target' is null, the cursor will visit every rule in 'cls'. * * - If 'target' is nonnull, the cursor will visit each 'rule' in 'cls' * such that cls_rule_is_loose_match(rule, target) returns true. * * Ignores target->priority. */ void cls_cursor_init(struct cls_cursor *cursor, const struct classifier *cls, const struct cls_rule *target) { cursor->cls = cls->cls; cursor->target = target && !cls_rule_is_catchall(target) ? target : NULL; } /* Returns the first matching cls_rule in 'cursor''s iteration, or a null * pointer if there are no matches. */ struct cls_rule * cls_cursor_first(struct cls_cursor *cursor) { struct cls_subtable *subtable; HMAP_FOR_EACH (subtable, hmap_node, &cursor->cls->subtables) { struct cls_match *rule = search_subtable(subtable, cursor->target); if (rule) { cursor->subtable = subtable; return rule->cls_rule; } } return NULL; } /* Returns the next matching cls_rule in 'cursor''s iteration, or a null * pointer if there are no more matches. */ struct cls_rule * cls_cursor_next(struct cls_cursor *cursor, const struct cls_rule *rule_) { struct cls_match *rule = CONST_CAST(struct cls_match *, rule_->cls_match); const struct cls_subtable *subtable; struct cls_match *next; next = next_rule_in_list__(rule); if (next->priority < rule->priority) { return next->cls_rule; } /* 'next' is the head of the list, that is, the rule that is included in * the subtable's hmap. (This is important when the classifier contains * rules that differ only in priority.) */ rule = next; HMAP_FOR_EACH_CONTINUE (rule, hmap_node, &cursor->subtable->rules) { if (rule_matches(rule, cursor->target)) { return rule->cls_rule; } } subtable = cursor->subtable; HMAP_FOR_EACH_CONTINUE (subtable, hmap_node, &cursor->cls->subtables) { rule = search_subtable(subtable, cursor->target); if (rule) { cursor->subtable = subtable; return rule->cls_rule; } } return NULL; } static struct cls_subtable * find_subtable(const struct cls_classifier *cls, const struct minimask *mask) { struct cls_subtable *subtable; HMAP_FOR_EACH_IN_BUCKET (subtable, hmap_node, minimask_hash(mask, 0), &cls->subtables) { if (minimask_equal(mask, &subtable->mask)) { return subtable; } } return NULL; } static struct cls_subtable * insert_subtable(struct cls_classifier *cls, const struct minimask *mask) { uint32_t hash = minimask_hash(mask, 0); struct cls_subtable *subtable; int i, index = 0; struct flow_wildcards old, new; uint8_t prev; struct cls_subtable_entry elem; int count = count_1bits(mask->masks.map); subtable = xzalloc(sizeof *subtable - sizeof mask->masks.inline_values + MINIFLOW_VALUES_SIZE(count)); hmap_init(&subtable->rules); miniflow_clone_inline(&subtable->mask.masks, &mask->masks, count); /* Init indices for segmented lookup, if any. */ flow_wildcards_init_catchall(&new); old = new; prev = 0; for (i = 0; i < cls->n_flow_segments; i++) { flow_wildcards_fold_minimask_range(&new, mask, prev, cls->flow_segments[i]); /* Add an index if it adds mask bits. */ if (!flow_wildcards_equal(&new, &old)) { hindex_init(&subtable->indices[index]); subtable->index_ofs[index] = cls->flow_segments[i]; index++; old = new; } prev = cls->flow_segments[i]; } /* Check if the rest of the subtable's mask adds any bits, * and remove the last index if it doesn't. */ if (index > 0) { flow_wildcards_fold_minimask_range(&new, mask, prev, FLOW_U32S); if (flow_wildcards_equal(&new, &old)) { --index; subtable->index_ofs[index] = 0; hindex_destroy(&subtable->indices[index]); } } subtable->n_indices = index; subtable->tag = (minimask_get_metadata_mask(mask) == OVS_BE64_MAX ? tag_create_deterministic(hash) : TAG_ALL); for (i = 0; i < cls->n_tries; i++) { subtable->trie_plen[i] = minimask_get_prefix_len(mask, cls->tries[i].field); } /* Ports trie. */ subtable->ports_trie = NULL; subtable->ports_mask_len = 32 - ctz32(ntohl(MINIFLOW_GET_BE32(&mask->masks, tp_src))); hmap_insert(&cls->subtables, &subtable->hmap_node, hash); elem.subtable = subtable; elem.tag = subtable->tag; elem.max_priority = subtable->max_priority; cls_subtable_cache_push_back(&cls->subtables_priority, elem); return subtable; } static void destroy_subtable(struct cls_classifier *cls, struct cls_subtable *subtable) { int i; struct cls_subtable *table = NULL; struct cls_subtable_entry *iter; CLS_SUBTABLE_CACHE_FOR_EACH (table, iter, &cls->subtables_priority) { if (table == subtable) { cls_subtable_cache_remove(&cls->subtables_priority, iter); break; } } trie_destroy(subtable->ports_trie); for (i = 0; i < subtable->n_indices; i++) { hindex_destroy(&subtable->indices[i]); } minimask_destroy(&subtable->mask); hmap_remove(&cls->subtables, &subtable->hmap_node); hmap_destroy(&subtable->rules); free(subtable); } /* This function performs the following updates for 'subtable' in 'cls' * following the addition of a new rule with priority 'new_priority' to * 'subtable': * * - Update 'subtable->max_priority' and 'subtable->max_count' if necessary. * * - Update 'subtable''s position in 'cls->subtables_priority' if necessary. * * This function should only be called after adding a new rule, not after * replacing a rule by an identical one or modifying a rule in-place. */ static void update_subtables_after_insertion(struct cls_classifier *cls, struct cls_subtable *subtable, unsigned int new_priority) { if (new_priority == subtable->max_priority) { ++subtable->max_count; } else if (new_priority > subtable->max_priority) { struct cls_subtable *table; struct cls_subtable_entry *iter, *subtable_iter = NULL; subtable->max_priority = new_priority; subtable->max_count = 1; /* Possibly move 'subtable' earlier in the priority list. If we break * out of the loop, then 'subtable_iter' should be moved just before * 'iter'. If the loop terminates normally, then 'iter' will be the * first list element and we'll move subtable just before that * (e.g. to the front of the list). */ CLS_SUBTABLE_CACHE_FOR_EACH_REVERSE (table, iter, &cls->subtables_priority) { if (table == subtable) { subtable_iter = iter; /* Locate the subtable as we go. */ iter->max_priority = new_priority; } else if (table->max_priority >= new_priority) { ovs_assert(subtable_iter != NULL); iter++; break; } } /* Move 'subtable' just before 'iter' (unless it's already there). */ if (iter != subtable_iter) { cls_subtable_cache_splice(iter, subtable_iter, subtable_iter + 1); } } } /* This function performs the following updates for 'subtable' in 'cls' * following the deletion of a rule with priority 'del_priority' from * 'subtable': * * - Update 'subtable->max_priority' and 'subtable->max_count' if necessary. * * - Update 'subtable''s position in 'cls->subtables_priority' if necessary. * * This function should only be called after removing a rule, not after * replacing a rule by an identical one or modifying a rule in-place. */ static void update_subtables_after_removal(struct cls_classifier *cls, struct cls_subtable *subtable, unsigned int del_priority) { if (del_priority == subtable->max_priority && --subtable->max_count == 0) { struct cls_match *head; struct cls_subtable *table; struct cls_subtable_entry *iter, *subtable_iter = NULL; subtable->max_priority = 0; HMAP_FOR_EACH (head, hmap_node, &subtable->rules) { if (head->priority > subtable->max_priority) { subtable->max_priority = head->priority; subtable->max_count = 1; } else if (head->priority == subtable->max_priority) { ++subtable->max_count; } } /* Possibly move 'subtable' later in the priority list. If we break * out of the loop, then 'subtable' should be moved just before that * 'iter'. If the loop terminates normally, then 'iter' will be the * list head and we'll move subtable just before that (e.g. to the back * of the list). */ CLS_SUBTABLE_CACHE_FOR_EACH (table, iter, &cls->subtables_priority) { if (table == subtable) { subtable_iter = iter; /* Locate the subtable as we go. */ iter->max_priority = subtable->max_priority; } else if (table->max_priority <= subtable->max_priority) { ovs_assert(subtable_iter != NULL); break; } } /* Move 'subtable' just before 'iter' (unless it's already there). */ if (iter != subtable_iter) { cls_subtable_cache_splice(iter, subtable_iter, subtable_iter + 1); } } } struct range { uint8_t start; uint8_t end; }; /* Return 'true' if can skip rest of the subtable based on the prefix trie * lookup results. */ static inline bool check_tries(struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries, const unsigned int field_plen[CLS_MAX_TRIES], const struct range ofs, const struct flow *flow, struct flow_wildcards *wc) { int j; /* Check if we could avoid fully unwildcarding the next level of * fields using the prefix tries. The trie checks are done only as * needed to avoid folding in additional bits to the wildcards mask. */ for (j = 0; j < n_tries; j++) { /* Is the trie field relevant for this subtable? */ if (field_plen[j]) { struct trie_ctx *ctx = &trie_ctx[j]; uint8_t be32ofs = ctx->be32ofs; /* Is the trie field within the current range of fields? */ if (be32ofs >= ofs.start && be32ofs < ofs.end) { /* On-demand trie lookup. */ if (!ctx->lookup_done) { ctx->match_plen = trie_lookup(ctx->trie, flow, &ctx->maskbits); ctx->lookup_done = true; } /* Possible to skip the rest of the subtable if subtable's * prefix on the field is longer than what is known to match * based on the trie lookup. */ if (field_plen[j] > ctx->match_plen) { /* RFC: We want the trie lookup to never result in * unwildcarding any bits that would not be unwildcarded * otherwise. Since the trie is shared by the whole * classifier, it is possible that the 'maskbits' contain * bits that are irrelevant for the partition of the * classifier relevant for the current flow. */ /* Can skip if the field is already unwildcarded. */ if (mask_prefix_bits_set(wc, be32ofs, ctx->maskbits)) { return true; } /* Check that the trie result will not unwildcard more bits * than this stage will. */ if (ctx->maskbits <= field_plen[j]) { /* Unwildcard the bits and skip the rest. */ mask_set_prefix_bits(wc, be32ofs, ctx->maskbits); /* Note: Prerequisite already unwildcarded, as the only * prerequisite of the supported trie lookup fields is * the ethertype, which is currently always * unwildcarded. */ return true; } } } } } 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 it is faster because of the invariant that * flow->map and mask->masks.map are the same. */ static inline bool miniflow_and_mask_matches_flow(const struct miniflow *flow, const struct minimask *mask, const struct flow *target) { const uint32_t *flowp = miniflow_get_u32_values(flow); const uint32_t *maskp = miniflow_get_u32_values(&mask->masks); uint32_t target_u32; FLOW_FOR_EACH_IN_MAP(target_u32, target, mask->masks.map) { if ((*flowp++ ^ target_u32) & *maskp++) { return false; } } return true; } static inline struct cls_match * find_match(const struct cls_subtable *subtable, const struct flow *flow, uint32_t hash) { struct cls_match *rule; HMAP_FOR_EACH_WITH_HASH (rule, hmap_node, hash, &subtable->rules) { if (miniflow_and_mask_matches_flow(&rule->flow, &subtable->mask, flow)) { return rule; } } return NULL; } static struct cls_match * find_match_wc(const struct cls_subtable *subtable, const struct flow *flow, struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries, struct flow_wildcards *wc) { uint32_t basis = 0, hash; struct cls_match *rule = NULL; int i; struct range ofs; if (OVS_UNLIKELY(!wc)) { return find_match(subtable, flow, flow_hash_in_minimask(flow, &subtable->mask, 0)); } ofs.start = 0; /* Try to finish early by checking fields in segments. */ for (i = 0; i < subtable->n_indices; i++) { struct hindex_node *inode; ofs.end = subtable->index_ofs[i]; if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow, wc)) { goto range_out; } hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start, ofs.end, &basis); ofs.start = ofs.end; inode = hindex_node_with_hash(&subtable->indices[i], hash); if (!inode) { /* No match, can stop immediately, but must fold in the mask * covered so far. */ goto range_out; } /* If we have narrowed down to a single rule already, check whether * that rule matches. If it does match, then we're done. If it does * not match, then we know that we will never get a match, but we do * not yet know how many wildcards we need to fold into 'wc' so we * continue iterating through indices to find that out. (We won't * waste time calling miniflow_and_mask_matches_flow() again because * we've set 'rule' nonnull.) * * This check shows a measurable benefit with non-trivial flow tables. * * (Rare) hash collisions may cause us to miss the opportunity for this * optimization. */ if (!inode->s && !rule) { ASSIGN_CONTAINER(rule, inode - i, index_nodes); if (miniflow_and_mask_matches_flow(&rule->flow, &subtable->mask, flow)) { goto out; } } } ofs.end = FLOW_U32S; /* Trie check for the final range. */ if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow, wc)) { goto range_out; } if (!rule) { /* Multiple potential matches exist, look for one. */ hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start, ofs.end, &basis); rule = find_match(subtable, flow, hash); } else { /* We already narrowed the matching candidates down to just 'rule', * but it didn't match. */ rule = NULL; } if (!rule && subtable->ports_mask_len) { /* Ports are always part of the final range, if any. * No match was found for the ports. Use the ports trie to figure out * which ports bits to unwildcard. */ unsigned int mbits; ovs_be32 value, mask; mask = MINIFLOW_GET_BE32(&subtable->mask.masks, tp_src); value = ((OVS_FORCE ovs_be32 *)flow)[TP_PORTS_OFS32] & mask; trie_lookup_value(subtable->ports_trie, &value, &mbits); ((OVS_FORCE ovs_be32 *)&wc->masks)[TP_PORTS_OFS32] |= mask & htonl(~0 << (32 - mbits)); ofs.start = TP_PORTS_OFS32; goto range_out; } out: /* Must unwildcard all the fields, as they were looked at. */ flow_wildcards_fold_minimask(wc, &subtable->mask); return rule; range_out: /* Must unwildcard the fields looked up so far, if any. */ if (ofs.start) { flow_wildcards_fold_minimask_range(wc, &subtable->mask, 0, ofs.start); } return NULL; } static struct cls_match * find_equal(struct cls_subtable *subtable, const struct miniflow *flow, uint32_t hash) { struct cls_match *head; HMAP_FOR_EACH_WITH_HASH (head, hmap_node, hash, &subtable->rules) { if (miniflow_equal(&head->flow, flow)) { return head; } } return NULL; } static struct cls_match * insert_rule(struct cls_classifier *cls, struct cls_subtable *subtable, struct cls_rule *new) { struct cls_match *cls_match = cls_match_alloc(new); struct cls_match *head; struct cls_match *old = NULL; int i; uint32_t basis = 0, hash; uint8_t prev_be32ofs = 0; /* Add new node to segment indices. */ for (i = 0; i < subtable->n_indices; i++) { hash = minimatch_hash_range(&new->match, prev_be32ofs, subtable->index_ofs[i], &basis); hindex_insert(&subtable->indices[i], &cls_match->index_nodes[i], hash); prev_be32ofs = subtable->index_ofs[i]; } hash = minimatch_hash_range(&new->match, prev_be32ofs, FLOW_U32S, &basis); head = find_equal(subtable, &new->match.flow, hash); if (!head) { hmap_insert(&subtable->rules, &cls_match->hmap_node, hash); list_init(&cls_match->list); goto out; } else { /* Scan the list for the insertion point that will keep the list in * order of decreasing priority. */ struct cls_match *rule; cls_match->hmap_node.hash = hash; /* Otherwise done by hmap_insert. */ FOR_EACH_RULE_IN_LIST (rule, head) { if (cls_match->priority >= rule->priority) { if (rule == head) { /* 'new' is the new highest-priority flow in the list. */ hmap_replace(&subtable->rules, &rule->hmap_node, &cls_match->hmap_node); } if (cls_match->priority == rule->priority) { list_replace(&cls_match->list, &rule->list); old = rule; goto out; } else { list_insert(&rule->list, &cls_match->list); goto out; } } } /* Insert 'new' at the end of the list. */ list_push_back(&head->list, &cls_match->list); } out: if (!old) { update_subtables_after_insertion(cls, subtable, cls_match->priority); } else { /* Remove old node from indices. */ for (i = 0; i < subtable->n_indices; i++) { hindex_remove(&subtable->indices[i], &old->index_nodes[i]); } } return old; } static struct cls_match * next_rule_in_list__(struct cls_match *rule) { struct cls_match *next = OBJECT_CONTAINING(rule->list.next, next, list); return next; } static struct cls_match * next_rule_in_list(struct cls_match *rule) { struct cls_match *next = next_rule_in_list__(rule); return next->priority < rule->priority ? next : NULL; } /* A longest-prefix match tree. */ struct trie_node { uint32_t prefix; /* Prefix bits for this node, MSB first. */ uint8_t nbits; /* Never zero, except for the root node. */ unsigned int n_rules; /* Number of rules that have this prefix. */ struct trie_node *edges[2]; /* Both NULL if leaf. */ }; /* Max bits per node. Must fit in struct trie_node's 'prefix'. * Also tested with 16, 8, and 5 to stress the implementation. */ #define TRIE_PREFIX_BITS 32 /* Return at least 'plen' bits of the 'prefix', starting at bit offset 'ofs'. * Prefixes are in the network byte order, and the offset 0 corresponds to * the most significant bit of the first byte. The offset can be read as * "how many bits to skip from the start of the prefix starting at 'pr'". */ static uint32_t raw_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen) { uint32_t prefix; pr += ofs / 32; /* Where to start. */ ofs %= 32; /* How many bits to skip at 'pr'. */ prefix = ntohl(*pr) << ofs; /* Get the first 32 - ofs bits. */ if (plen > 32 - ofs) { /* Need more than we have already? */ prefix |= ntohl(*++pr) >> (32 - ofs); } /* Return with possible unwanted bits at the end. */ return prefix; } /* Return min(TRIE_PREFIX_BITS, plen) bits of the 'prefix', starting at bit * offset 'ofs'. Prefixes are in the network byte order, and the offset 0 * corresponds to the most significant bit of the first byte. The offset can * be read as "how many bits to skip from the start of the prefix starting at * 'pr'". */ static uint32_t trie_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen) { if (!plen) { return 0; } if (plen > TRIE_PREFIX_BITS) { plen = TRIE_PREFIX_BITS; /* Get at most TRIE_PREFIX_BITS. */ } /* Return with unwanted bits cleared. */ return raw_get_prefix(pr, ofs, plen) & ~0u << (32 - plen); } /* Return the number of equal bits in 'nbits' of 'prefix's MSBs and a 'value' * starting at "MSB 0"-based offset 'ofs'. */ static unsigned int prefix_equal_bits(uint32_t prefix, unsigned int nbits, const ovs_be32 value[], unsigned int ofs) { uint64_t diff = prefix ^ raw_get_prefix(value, ofs, nbits); /* Set the bit after the relevant bits to limit the result. */ return raw_clz64(diff << 32 | UINT64_C(1) << (63 - nbits)); } /* Return the number of equal bits in 'node' prefix and a 'prefix' of length * 'plen', starting at "MSB 0"-based offset 'ofs'. */ static unsigned int trie_prefix_equal_bits(const struct trie_node *node, const ovs_be32 prefix[], unsigned int ofs, unsigned int plen) { return prefix_equal_bits(node->prefix, MIN(node->nbits, plen - ofs), prefix, ofs); } /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' can * be greater than 31. */ static unsigned int be_get_bit_at(const ovs_be32 value[], unsigned int ofs) { return (((const uint8_t *)value)[ofs / 8] >> (7 - ofs % 8)) & 1u; } /* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' must * be between 0 and 31, inclusive. */ static unsigned int get_bit_at(const uint32_t prefix, unsigned int ofs) { return (prefix >> (31 - ofs)) & 1u; } /* Create new branch. */ static struct trie_node * trie_branch_create(const ovs_be32 *prefix, unsigned int ofs, unsigned int plen, unsigned int n_rules) { struct trie_node *node = xmalloc(sizeof *node); node->prefix = trie_get_prefix(prefix, ofs, plen); if (plen <= TRIE_PREFIX_BITS) { node->nbits = plen; node->edges[0] = NULL; node->edges[1] = NULL; node->n_rules = n_rules; } else { /* Need intermediate nodes. */ struct trie_node *subnode = trie_branch_create(prefix, ofs + TRIE_PREFIX_BITS, plen - TRIE_PREFIX_BITS, n_rules); int bit = get_bit_at(subnode->prefix, 0); node->nbits = TRIE_PREFIX_BITS; node->edges[bit] = subnode; node->edges[!bit] = NULL; node->n_rules = 0; } return node; } static void trie_node_destroy(struct trie_node *node) { free(node); } static void trie_destroy(struct trie_node *node) { if (node) { trie_destroy(node->edges[0]); trie_destroy(node->edges[1]); free(node); } } static bool trie_is_leaf(const struct trie_node *trie) { return !trie->edges[0] && !trie->edges[1]; /* No children. */ } static void mask_set_prefix_bits(struct flow_wildcards *wc, uint8_t be32ofs, unsigned int nbits) { ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs]; unsigned int i; for (i = 0; i < nbits / 32; i++) { mask[i] = OVS_BE32_MAX; } if (nbits % 32) { mask[i] |= htonl(~0u << (32 - nbits % 32)); } } static bool mask_prefix_bits_set(const struct flow_wildcards *wc, uint8_t be32ofs, unsigned int nbits) { ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs]; unsigned int i; ovs_be32 zeroes = 0; for (i = 0; i < nbits / 32; i++) { zeroes |= ~mask[i]; } if (nbits % 32) { zeroes |= ~mask[i] & htonl(~0u << (32 - nbits % 32)); } return !zeroes; /* All 'nbits' bits set. */ } static struct trie_node ** trie_next_edge(struct trie_node *node, const ovs_be32 value[], unsigned int ofs) { return node->edges + be_get_bit_at(value, ofs); } static const struct trie_node * trie_next_node(const struct trie_node *node, const ovs_be32 value[], unsigned int ofs) { return node->edges[be_get_bit_at(value, ofs)]; } /* Return the prefix mask length necessary to find the longest-prefix match for * the '*value' in the prefix tree 'node'. * '*checkbits' is set to the number of bits in the prefix mask necessary to * determine a mismatch, in case there are longer prefixes in the tree below * the one that matched. */ static unsigned int trie_lookup_value(const struct trie_node *node, const ovs_be32 value[], unsigned int *checkbits) { unsigned int plen = 0, match_len = 0; const struct trie_node *prev = NULL; for (; node; prev = node, node = trie_next_node(node, value, plen)) { unsigned int eqbits; /* Check if this edge can be followed. */ eqbits = prefix_equal_bits(node->prefix, node->nbits, value, plen); plen += eqbits; if (eqbits < node->nbits) { /* Mismatch, nothing more to be found. */ /* Bit at offset 'plen' differed. */ *checkbits = plen + 1; /* Includes the first mismatching bit. */ return match_len; } /* Full match, check if rules exist at this prefix length. */ if (node->n_rules > 0) { match_len = plen; } } /* Dead end, exclude the other branch if it exists. */ *checkbits = !prev || trie_is_leaf(prev) ? plen : plen + 1; return match_len; } static unsigned int trie_lookup(const struct cls_trie *trie, const struct flow *flow, unsigned int *checkbits) { const struct mf_field *mf = trie->field; /* Check that current flow matches the prerequisites for the trie * field. Some match fields are used for multiple purposes, so we * must check that the trie is relevant for this flow. */ if (mf_are_prereqs_ok(mf, flow)) { return trie_lookup_value(trie->root, &((ovs_be32 *)flow)[mf->flow_be32ofs], checkbits); } *checkbits = 0; /* Value not used in this case. */ return UINT_MAX; } /* Returns the length of a prefix match mask for the field 'mf' in 'minimask'. * Returns the u32 offset to the miniflow data in '*miniflow_index', if * 'miniflow_index' is not NULL. */ static unsigned int minimask_get_prefix_len(const struct minimask *minimask, const struct mf_field *mf) { unsigned int nbits = 0, mask_tz = 0; /* Non-zero when end of mask seen. */ uint8_t u32_ofs = mf->flow_be32ofs; uint8_t u32_end = u32_ofs + mf->n_bytes / 4; for (; u32_ofs < u32_end; ++u32_ofs) { uint32_t mask; mask = ntohl((OVS_FORCE ovs_be32)minimask_get(minimask, u32_ofs)); /* Validate mask, count the mask length. */ if (mask_tz) { if (mask) { return 0; /* No bits allowed after mask ended. */ } } else { if (~mask & (~mask + 1)) { return 0; /* Mask not contiguous. */ } mask_tz = ctz32(mask); nbits += 32 - mask_tz; } } return nbits; } /* * This is called only when mask prefix is known to be CIDR and non-zero. * Relies on the fact that the flow and mask have the same map, and since * the mask is CIDR, the storage for the flow field exists even if it * happened to be zeros. */ static const ovs_be32 * minimatch_get_prefix(const struct minimatch *match, const struct mf_field *mf) { return miniflow_get_be32_values(&match->flow) + count_1bits(match->flow.map & ((UINT64_C(1) << mf->flow_be32ofs) - 1)); } /* Insert rule in to the prefix tree. * 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask * in 'rule'. */ static void trie_insert(struct cls_trie *trie, const struct cls_rule *rule, int mlen) { trie_insert_prefix(&trie->root, minimatch_get_prefix(&rule->match, trie->field), mlen); } static void trie_insert_prefix(struct trie_node **edge, const ovs_be32 *prefix, int mlen) { struct trie_node *node; int ofs = 0; /* Walk the tree. */ for (; (node = *edge) != NULL; edge = trie_next_edge(node, prefix, ofs)) { unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen); ofs += eqbits; if (eqbits < node->nbits) { /* Mismatch, new node needs to be inserted above. */ int old_branch = get_bit_at(node->prefix, eqbits); /* New parent node. */ *edge = trie_branch_create(prefix, ofs - eqbits, eqbits, ofs == mlen ? 1 : 0); /* Adjust old node for its new position in the tree. */ node->prefix <<= eqbits; node->nbits -= eqbits; (*edge)->edges[old_branch] = node; /* Check if need a new branch for the new rule. */ if (ofs < mlen) { (*edge)->edges[!old_branch] = trie_branch_create(prefix, ofs, mlen - ofs, 1); } return; } /* Full match so far. */ if (ofs == mlen) { /* Full match at the current node, rule needs to be added here. */ node->n_rules++; return; } } /* Must insert a new tree branch for the new rule. */ *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(struct trie_node **root, const ovs_be32 *prefix, int mlen) { struct trie_node *node; struct trie_node **edges[sizeof(union mf_value) * 8]; int depth = 0, ofs = 0; /* Walk the tree. */ for (edges[0] = root; (node = *edges[depth]) != NULL; edges[++depth] = trie_next_edge(node, prefix, ofs)) { unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen); if (eqbits < node->nbits) { /* Mismatch, nothing to be removed. This should never happen, as * only rules in the classifier are ever removed. */ break; /* Log a warning. */ } /* Full match so far. */ ofs += eqbits; if (ofs == mlen) { /* Full prefix match at the current node, remove rule here. */ if (!node->n_rules) { break; /* Log a warning. */ } node->n_rules--; /* Check if can prune the tree. */ while (!node->n_rules && !(node->edges[0] && node->edges[1])) { /* No rules and at most one child node, remove this node. */ struct trie_node *next; next = node->edges[0] ? node->edges[0] : node->edges[1]; if (next) { if (node->nbits + next->nbits > TRIE_PREFIX_BITS) { break; /* Cannot combine. */ } /* Combine node with next. */ next->prefix = node->prefix | next->prefix >> node->nbits; next->nbits += node->nbits; } trie_node_destroy(node); /* Update the parent's edge. */ *edges[depth] = next; if (next || !depth) { /* Branch not pruned or at root, nothing more to do. */ break; } node = *edges[--depth]; } return; } } /* 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."); }