X-Git-Url: http://git.cascardo.eti.br/?a=blobdiff_plain;f=lib%2Fclassifier.h;h=8e3bf612fb0a5b8fd49cd431f7c01e773dc6552d;hb=f4faf4baf7a22316d5a083af57557a97f9c93775;hp=126d1498acd918622185bc39d7f48ed413cd4a26;hpb=a0bc29a541fc7dc6e20137d5558e2094d614e6ab;p=cascardo%2Fovs.git diff --git a/lib/classifier.h b/lib/classifier.h index 126d1498a..8e3bf612f 100644 --- a/lib/classifier.h +++ b/lib/classifier.h @@ -1,5 +1,5 @@ /* - * Copyright (c) 2009, 2010 Nicira Networks. + * Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -19,150 +19,231 @@ /* Flow classifier. * - * This flow classifier assumes that we can arrange the fields in a flow in an - * order such that the set of wildcarded fields in a rule tend to fall toward - * the end of the ordering. That is, if field F is wildcarded, then all the - * fields after F tend to be wildcarded as well. If this assumption is - * violated, then the classifier will still classify flows correctly, but its - * performance will suffer. - * - * The classifier uses a collection of CLS_N_FIELDS hash tables for wildcarded - * flows. Each of these tables contains the flows that wildcard a given field - * and do not wildcard any of the fields that precede F in the ordering. The - * key for each hash table is the value of the fields preceding F that are not - * wildcarded. All the flows that fall within a table and have the same key - * are kept as a linked list ordered from highest to lowest priority. - * - * The classifier also maintains a separate hash table of exact-match flows. - * - * To search the classifier we first search the table of exact-match flows, - * since exact-match flows always have highest priority. If there is a match, - * we're done. Otherwise, we search each of the CLS_N_FIELDS hash tables in - * turn, looking for the highest-priority match, and return it (if any). - */ + * + * What? + * ===== + * + * A flow classifier holds any number of "rules", each of which specifies + * values to match for some fields or subfields and a priority. The primary + * design goal for the classifier is that, given a packet, it can as quickly as + * possible find the highest-priority rule that matches the packet. + * + * Each OpenFlow table is implemented as a flow classifier. + * + * + * Basic Design + * ============ + * + * Suppose that all the rules in a classifier had the same form. For example, + * suppose that they all matched on the source and destination Ethernet address + * and wildcarded all the other fields. Then the obvious way to implement a + * classifier would be a hash table on the source and destination Ethernet + * addresses. If new classification rules came along with a different form, + * you could add a second hash table that hashed on the fields matched in those + * rules. With two hash tables, you look up a given flow in each hash table. + * If there are no matches, the classifier didn't contain a match; if you find + * a match in one of them, that's the result; if you find a match in both of + * them, then the result is the rule with the higher priority. + * + * This is how the classifier works. In a "struct classifier", each form of + * "struct cls_rule" present (based on its ->match.mask) goes into a separate + * "struct cls_table". A lookup does a hash lookup in every "struct cls_table" + * in the classifier and tracks the highest-priority match that it finds. The + * tables are kept in a descending priority order according to the highest + * priority rule in each table, which allows lookup to skip over tables that + * can't possibly have a higher-priority match than already found. + * + * One detail: a classifier can contain multiple rules that are identical other + * than their priority. When this happens, only the highest priority rule out + * of a group of otherwise identical rules is stored directly in the "struct + * cls_table", with the other almost-identical rules chained off a linked list + * inside that highest-priority rule. + * + * + * Partitioning + * ============ + * + * Suppose that a given classifier is being used to handle multiple stages in a + * pipeline using "resubmit", with metadata (that is, the OpenFlow 1.1+ field + * named "metadata") distinguishing between the different stages. For example, + * metadata value 1 might identify ingress rules, metadata value 2 might + * identify ACLs, and metadata value 3 might identify egress rules. Such a + * classifier is essentially partitioned into multiple sub-classifiers on the + * basis of the metadata value. + * + * The classifier has a special optimization to speed up matching in this + * scenario: + * + * - Each cls_table that matches on metadata gets a tag derived from the + * table's mask, so that it is likely that each table has a unique tag. + * (Duplicate tags have a performance cost but do not affect + * correctness.) + * + * - For each metadata value matched by any cls_rule, the classifier + * constructs a "struct cls_partition" indexed by the metadata value. + * The cls_partition has a 'tags' member whose value is the bitwise-OR of + * the tags of each cls_table that contains any rule that matches on the + * cls_partition's metadata value. In other words, struct cls_partition + * associates metadata values with tables that need to be checked with + * flows with that specific metadata value. + * + * Thus, a flow lookup can start by looking up the partition associated with + * the flow's metadata, and then skip over any cls_table whose 'tag' does not + * intersect the partition's 'tags'. (The flow must also be looked up in any + * cls_table that doesn't match on metadata. We handle that by giving any such + * cls_table TAG_ALL as its 'tags' so that it matches any tag.) + * + * + * Thread-safety + * ============= + * + * When locked properly, the classifier is thread safe as long as the following + * conditions are satisfied. + * - Only the main thread calls functions requiring a write lock. + * - Only the main thread is allowed to iterate over rules. */ #include "flow.h" #include "hmap.h" #include "list.h" +#include "match.h" +#include "tag.h" +#include "openflow/nicira-ext.h" #include "openflow/openflow.h" +#include "ovs-thread.h" +#include "util.h" -/* Number of bytes of fields in a rule. */ -#define CLS_N_BYTES 31 - -/* Fields in a rule. - * - * This definition sets the ordering of fields, which is important for - * performance (see above). To adjust the ordering, change the order of the - * lines. */ -#define CLS_FIELDS \ - /* flow_t all-caps */ \ - /* wildcard bit(s) member name name */ \ - /* ----------------- ----------- -------- */ \ - CLS_FIELD(OFPFW_IN_PORT, in_port, IN_PORT) \ - CLS_FIELD(OFPFW_DL_VLAN, dl_vlan, DL_VLAN) \ - CLS_FIELD(OFPFW_DL_VLAN_PCP, dl_vlan_pcp, DL_VLAN_PCP) \ - CLS_FIELD(OFPFW_DL_SRC, dl_src, DL_SRC) \ - CLS_FIELD(OFPFW_DL_DST, dl_dst, DL_DST) \ - CLS_FIELD(OFPFW_DL_TYPE, dl_type, DL_TYPE) \ - CLS_FIELD(OFPFW_NW_SRC_MASK, nw_src, NW_SRC) \ - CLS_FIELD(OFPFW_NW_DST_MASK, nw_dst, NW_DST) \ - CLS_FIELD(OFPFW_NW_PROTO, nw_proto, NW_PROTO) \ - CLS_FIELD(OFPFW_NW_TOS, nw_tos, NW_TOS) \ - CLS_FIELD(OFPFW_TP_SRC, tp_src, TP_SRC) \ - CLS_FIELD(OFPFW_TP_DST, tp_dst, TP_DST) - -/* Field indexes. - * - * (These are also indexed into struct classifier's 'tables' array.) */ -enum { -#define CLS_FIELD(WILDCARDS, MEMBER, NAME) CLS_F_IDX_##NAME, - CLS_FIELDS -#undef CLS_FIELD - CLS_F_IDX_EXACT, /* Exact-match table. */ - CLS_N_FIELDS = CLS_F_IDX_EXACT -}; +#ifdef __cplusplus +extern "C" { +#endif -/* Field information. */ -struct cls_field { - int ofs; /* Offset in flow_t. */ - int len; /* Length in bytes. */ - uint32_t wildcards; /* OFPFW_* bit or bits for this field. */ - const char *name; /* Name (for debugging). */ -}; -extern const struct cls_field cls_fields[CLS_N_FIELDS + 1]; +/* Needed only for the lock annotation in struct classifier. */ +extern struct ovs_mutex ofproto_mutex; /* A flow classifier. */ struct classifier { - int n_rules; /* Sum of hmap_count() over tables[]. */ - struct hmap tables[CLS_N_FIELDS]; /* Contain cls_bucket elements. */ - struct hmap exact_table; /* Contain cls_rule elements. */ + int n_rules; /* Total number of rules. */ + struct hmap tables; /* Contains "struct cls_table"s. */ + struct list tables_priority; /* Tables in descending priority order */ + struct hmap partitions; /* Contains "struct cls_partition"s. */ + struct ovs_rwlock rwlock OVS_ACQ_AFTER(ofproto_mutex); }; -/* A group of rules with the same fixed values for initial fields. */ -struct cls_bucket { - struct hmap_node hmap_node; /* Within struct classifier 'tables'. */ - struct list rules; /* In order from highest to lowest priority. */ - flow_t fixed; /* Values for fixed fields. */ +/* A set of rules that all have the same fields wildcarded. */ +struct cls_table { + struct hmap_node hmap_node; /* Within struct classifier 'tables' hmap. */ + struct list list_node; /* Within classifier 'tables_priority_list' */ + struct hmap rules; /* Contains "struct cls_rule"s. */ + struct minimask mask; /* Wildcards for fields. */ + int n_table_rules; /* Number of rules, including duplicates. */ + unsigned int max_priority; /* Max priority of any rule in the table. */ + unsigned int max_count; /* Count of max_priority rules. */ + tag_type tag; /* Tag generated from mask for partitioning. */ }; -/* A flow classification rule. - * - * Use cls_rule_from_flow() or cls_rule_from_match() to initialize a cls_rule - * or you will almost certainly not initialize 'table_idx' correctly, with - * disastrous results! */ +/* Returns true if 'table' is a "catch-all" table that will match every + * packet (if there is no higher-priority match). */ +static inline bool +cls_table_is_catchall(const struct cls_table *table) +{ + return minimask_is_catchall(&table->mask); +} + +/* A rule in a "struct cls_table". */ struct cls_rule { - union { - struct list list; /* Within struct cls_bucket 'rules'. */ - struct hmap_node hmap; /* Within struct classifier 'exact_table'. */ - } node; - flow_t flow; /* All field values. */ - struct flow_wildcards wc; /* Wildcards for fields. */ + struct hmap_node hmap_node; /* Within struct cls_table 'rules'. */ + struct list list; /* List of identical, lower-priority rules. */ + struct minimatch match; /* Matching rule. */ unsigned int priority; /* Larger numbers are higher priorities. */ - unsigned int table_idx; /* Index into struct classifier 'tables'. */ + struct cls_partition *partition; }; -void cls_rule_from_flow(struct cls_rule *, const flow_t *, uint32_t wildcards, - unsigned int priority); -void cls_rule_from_match(struct cls_rule *, const struct ofp_match *, - unsigned int priority); -char *cls_rule_to_string(const struct cls_rule *); -void cls_rule_print(const struct cls_rule *); -void cls_rule_moved(struct classifier *, - struct cls_rule *old, struct cls_rule *new); -void cls_rule_replace(struct classifier *, const struct cls_rule *old, - struct cls_rule *new); - -void classifier_init(struct classifier *); +/* Associates a metadata value (that is, a value of the OpenFlow 1.1+ metadata + * field) with tags for the "cls_table"s that contain rules that match that + * metadata value. */ +struct cls_partition { + struct hmap_node hmap_node; /* In struct classifier's 'partitions' hmap. */ + ovs_be64 metadata; /* metadata value for this partition. */ + tag_type tags; /* OR of each included flow's cls_table tag. */ + struct tag_tracker tracker; /* Tracks the bits in 'tags'. */ +}; + +void cls_rule_init(struct cls_rule *, const struct match *, + unsigned int priority); +void cls_rule_init_from_minimatch(struct cls_rule *, const struct minimatch *, + unsigned int priority); +void cls_rule_clone(struct cls_rule *, const struct cls_rule *); +void cls_rule_move(struct cls_rule *dst, struct cls_rule *src); +void cls_rule_destroy(struct cls_rule *); + +bool cls_rule_equal(const struct cls_rule *, const struct cls_rule *); +uint32_t cls_rule_hash(const struct cls_rule *, uint32_t basis); + +void cls_rule_format(const struct cls_rule *, struct ds *); + +bool cls_rule_is_catchall(const struct cls_rule *); + +bool cls_rule_is_loose_match(const struct cls_rule *rule, + const struct minimatch *criteria); + +void classifier_init(struct classifier *cls); void classifier_destroy(struct classifier *); -bool classifier_is_empty(const struct classifier *); -int classifier_count(const struct classifier *); -int classifier_count_exact(const struct classifier *); -struct cls_rule *classifier_insert(struct classifier *, struct cls_rule *); -void classifier_insert_exact(struct classifier *, struct cls_rule *); -void classifier_remove(struct classifier *, struct cls_rule *); -struct cls_rule *classifier_lookup(const struct classifier *, const flow_t *); -struct cls_rule *classifier_lookup_wild(const struct classifier *, - const flow_t *); -struct cls_rule *classifier_lookup_exact(const struct classifier *, - const flow_t *); -bool classifier_rule_overlaps(const struct classifier *, const flow_t *, - uint32_t wildcards, unsigned int priority); +bool classifier_is_empty(const struct classifier *cls) + OVS_REQ_RDLOCK(cls->rwlock); +int classifier_count(const struct classifier *cls) + OVS_REQ_RDLOCK(cls->rwlock); +void classifier_insert(struct classifier *cls, struct cls_rule *) + OVS_REQ_WRLOCK(cls->rwlock); +struct cls_rule *classifier_replace(struct classifier *cls, struct cls_rule *) + OVS_REQ_WRLOCK(cls->rwlock); +void classifier_remove(struct classifier *cls, struct cls_rule *) + OVS_REQ_WRLOCK(cls->rwlock); +struct cls_rule *classifier_lookup(const struct classifier *cls, + const struct flow *, + struct flow_wildcards *) + OVS_REQ_RDLOCK(cls->rwlock); +bool classifier_rule_overlaps(const struct classifier *cls, + const struct cls_rule *) + OVS_REQ_RDLOCK(cls->rwlock); typedef void cls_cb_func(struct cls_rule *, void *aux); -enum { - CLS_INC_EXACT = 1 << 0, /* Include exact-match flows? */ - CLS_INC_WILD = 1 << 1, /* Include flows with wildcards? */ - CLS_INC_ALL = CLS_INC_EXACT | CLS_INC_WILD +struct cls_rule *classifier_find_rule_exactly(const struct classifier *cls, + const struct cls_rule *) + OVS_REQ_RDLOCK(cls->rwlock); +struct cls_rule *classifier_find_match_exactly(const struct classifier *cls, + const struct match *, + unsigned int priority) + OVS_REQ_RDLOCK(cls->rwlock); + +/* Iteration. */ + +struct cls_cursor { + const struct classifier *cls; + const struct cls_table *table; + const struct cls_rule *target; }; -void classifier_for_each(const struct classifier *, int include, - cls_cb_func *, void *aux); -void classifier_for_each_match(const struct classifier *, - const struct cls_rule *, - int include, cls_cb_func *, void *aux); -struct cls_rule *classifier_find_rule_exactly(const struct classifier *, - const flow_t *target, - uint32_t wildcards, - unsigned int priority); + +void cls_cursor_init(struct cls_cursor *cursor, const struct classifier *cls, + const struct cls_rule *match) OVS_REQ_RDLOCK(cls->rwlock); +struct cls_rule *cls_cursor_first(struct cls_cursor *cursor); +struct cls_rule *cls_cursor_next(struct cls_cursor *cursor, const struct cls_rule *); + +#define CLS_CURSOR_FOR_EACH(RULE, MEMBER, CURSOR) \ + for (ASSIGN_CONTAINER(RULE, cls_cursor_first(CURSOR), MEMBER); \ + RULE != OBJECT_CONTAINING(NULL, RULE, MEMBER); \ + ASSIGN_CONTAINER(RULE, cls_cursor_next(CURSOR, &(RULE)->MEMBER), \ + MEMBER)) + +#define CLS_CURSOR_FOR_EACH_SAFE(RULE, NEXT, MEMBER, CURSOR) \ + for (ASSIGN_CONTAINER(RULE, cls_cursor_first(CURSOR), MEMBER); \ + (RULE != OBJECT_CONTAINING(NULL, RULE, MEMBER) \ + ? ASSIGN_CONTAINER(NEXT, cls_cursor_next(CURSOR, &(RULE)->MEMBER), \ + MEMBER), 1 \ + : 0); \ + (RULE) = (NEXT)) + +#ifdef __cplusplus +} +#endif #endif /* classifier.h */