/*
- * Copyright (c) 2009, 2010, 2011, 2012 Nicira, Inc.
+ * 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.
/* Flow classifier.
*
- * A classifier is a "struct classifier",
- * a hash map from a set of wildcards to a "struct cls_table",
- * a hash map from fixed field values to "struct cls_rule",
- * which can contain a list of otherwise identical rules
- * with lower priorities.
- */
+ *
+ * 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"
#ifdef __cplusplus
extern "C" {
#endif
+/* Needed only for the lock annotation in struct classifier. */
+extern struct ovs_mutex ofproto_mutex;
+
/* A flow classifier. */
struct classifier {
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 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 flow_wildcards wc; /* Wildcards for fields. */
+ struct minimask mask; /* Wildcards for fields. */
int n_table_rules; /* Number of rules, including duplicates. */
- bool is_catchall; /* True if this table wildcards every field. */
+ 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. */
};
/* Returns true if 'table' is a "catch-all" table that will match every
static inline bool
cls_table_is_catchall(const struct cls_table *table)
{
- return table->is_catchall;
+ return minimask_is_catchall(&table->mask);
}
-/* A flow classification rule.
- *
- * Use one of the cls_rule_*() functions to initialize a cls_rule.
- *
- * The cls_rule_*() functions below maintain the following important
- * invariant that the classifier depends on:
- *
- * - If a bit or a field is wildcarded in 'wc', then the corresponding bit or
- * field in 'flow' is set to all-0-bits. (The
- * cls_rule_zero_wildcarded_fields() function can be used to restore this
- * invariant after adding wildcards.)
- */
+/* A rule in a "struct classifier". */
struct cls_rule {
struct hmap_node hmap_node; /* Within struct cls_table 'rules'. */
struct list list; /* List of identical, lower-priority rules. */
- struct flow flow; /* All field values. */
- struct flow_wildcards wc; /* Wildcards for fields. */
+ struct minimatch match; /* Matching rule. */
unsigned int priority; /* Larger numbers are higher priorities. */
+ struct cls_partition *partition;
};
-void cls_rule_init(const struct flow *, const struct flow_wildcards *,
- unsigned int priority, struct cls_rule *);
-void cls_rule_init_exact(const struct flow *, unsigned int priority,
- struct cls_rule *);
-void cls_rule_init_catchall(struct cls_rule *, unsigned int priority);
-
-void cls_rule_zero_wildcarded_fields(struct cls_rule *);
+/* 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. */
+ unsigned int n_refs; /* # of flows that refer to this partition. */
+};
-bool cls_rule_is_loose_match(const struct cls_rule *rule,
- const struct cls_rule *criteria);
-
-void cls_rule_set_reg(struct cls_rule *, unsigned int reg_idx, uint32_t value);
-void cls_rule_set_reg_masked(struct cls_rule *, unsigned int reg_idx,
- uint32_t value, uint32_t mask);
-void cls_rule_set_metadata(struct cls_rule *, ovs_be64 metadata);
-void cls_rule_set_metadata_masked(struct cls_rule *, ovs_be64 metadata,
- ovs_be64 mask);
-void cls_rule_set_tun_id(struct cls_rule *, ovs_be64 tun_id);
-void cls_rule_set_tun_id_masked(struct cls_rule *,
- ovs_be64 tun_id, ovs_be64 mask);
-void cls_rule_set_in_port(struct cls_rule *, uint16_t ofp_port);
-void cls_rule_set_dl_type(struct cls_rule *, ovs_be16);
-void cls_rule_set_dl_src(struct cls_rule *, const uint8_t[6]);
-void cls_rule_set_dl_src_masked(struct cls_rule *, const uint8_t dl_src[6],
- const uint8_t mask[6]);
-void cls_rule_set_dl_dst(struct cls_rule *, const uint8_t[6]);
-void cls_rule_set_dl_dst_masked(struct cls_rule *, const uint8_t dl_dst[6],
- const uint8_t mask[6]);
-void cls_rule_set_dl_tci(struct cls_rule *, ovs_be16 tci);
-void cls_rule_set_dl_tci_masked(struct cls_rule *,
- ovs_be16 tci, ovs_be16 mask);
-void cls_rule_set_any_vid(struct cls_rule *);
-void cls_rule_set_dl_vlan(struct cls_rule *, ovs_be16);
-void cls_rule_set_any_pcp(struct cls_rule *);
-void cls_rule_set_dl_vlan_pcp(struct cls_rule *, uint8_t);
-void cls_rule_set_tp_src(struct cls_rule *, ovs_be16);
-void cls_rule_set_tp_src_masked(struct cls_rule *,
- ovs_be16 port, ovs_be16 mask);
-void cls_rule_set_tp_dst(struct cls_rule *, ovs_be16);
-void cls_rule_set_tp_dst_masked(struct cls_rule *,
- ovs_be16 port, ovs_be16 mask);
-void cls_rule_set_nw_proto(struct cls_rule *, uint8_t);
-void cls_rule_set_nw_src(struct cls_rule *, ovs_be32);
-void cls_rule_set_nw_src_masked(struct cls_rule *, ovs_be32 ip, ovs_be32 mask);
-void cls_rule_set_nw_dst(struct cls_rule *, ovs_be32);
-void cls_rule_set_nw_dst_masked(struct cls_rule *, ovs_be32 ip, ovs_be32 mask);
-void cls_rule_set_nw_dscp(struct cls_rule *, uint8_t);
-void cls_rule_set_nw_ecn(struct cls_rule *, uint8_t);
-void cls_rule_set_nw_ttl(struct cls_rule *, uint8_t);
-void cls_rule_set_nw_frag(struct cls_rule *, uint8_t nw_frag);
-void cls_rule_set_nw_frag_masked(struct cls_rule *,
- uint8_t nw_frag, uint8_t mask);
-void cls_rule_set_icmp_type(struct cls_rule *, uint8_t);
-void cls_rule_set_icmp_code(struct cls_rule *, uint8_t);
-void cls_rule_set_arp_sha(struct cls_rule *, const uint8_t[6]);
-void cls_rule_set_arp_tha(struct cls_rule *, const uint8_t[6]);
-void cls_rule_set_ipv6_src(struct cls_rule *, const struct in6_addr *);
-void cls_rule_set_ipv6_src_masked(struct cls_rule *, const struct in6_addr *,
- const struct in6_addr *);
-void cls_rule_set_ipv6_dst(struct cls_rule *, const struct in6_addr *);
-void cls_rule_set_ipv6_dst_masked(struct cls_rule *, const struct in6_addr *,
- const struct in6_addr *);
-void cls_rule_set_ipv6_label(struct cls_rule *, ovs_be32);
-void cls_rule_set_nd_target(struct cls_rule *, const struct in6_addr *);
-void cls_rule_set_nd_target_masked(struct cls_rule *, const struct in6_addr *,
- const struct in6_addr *);
+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 *);
-char *cls_rule_to_string(const struct cls_rule *);
-void cls_rule_print(const struct cls_rule *);
-void classifier_init(struct classifier *);
+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 *);
-void classifier_insert(struct classifier *, struct cls_rule *);
-struct cls_rule *classifier_replace(struct classifier *, struct cls_rule *);
-void classifier_remove(struct classifier *, struct cls_rule *);
-struct cls_rule *classifier_lookup(const struct classifier *,
- const struct flow *);
-bool classifier_rule_overlaps(const struct classifier *,
- const struct cls_rule *);
+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);
-struct cls_rule *classifier_find_rule_exactly(const struct classifier *,
- const struct cls_rule *);
+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);
\f
/* Iteration. */
const struct cls_rule *target;
};
-void cls_cursor_init(struct cls_cursor *, const struct classifier *,
- const struct cls_rule *match);
-struct cls_rule *cls_cursor_first(struct cls_cursor *);
-struct cls_rule *cls_cursor_next(struct cls_cursor *, struct cls_rule *);
+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)->MEMBER != NULL; \
+ 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)->MEMBER != NULL \
+ (RULE != OBJECT_CONTAINING(NULL, RULE, MEMBER) \
? ASSIGN_CONTAINER(NEXT, cls_cursor_next(CURSOR, &(RULE)->MEMBER), \
- MEMBER) \
+ MEMBER), 1 \
: 0); \
(RULE) = (NEXT))
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