/*
- * Copyright (c) 2008, 2009 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <config.h>
#include "mac-learning.h"
-#include <assert.h>
#include <inttypes.h>
#include <stdlib.h>
+#include "bitmap.h"
#include "coverage.h"
#include "hash.h"
#include "list.h"
#include "poll-loop.h"
-#include "tag.h"
#include "timeval.h"
+#include "unaligned.h"
#include "util.h"
+#include "vlan-bitmap.h"
-#define THIS_MODULE VLM_mac_learning
-#include "vlog.h"
+COVERAGE_DEFINE(mac_learning_learned);
+COVERAGE_DEFINE(mac_learning_expired);
+
+/* Returns the number of seconds since 'e' (within 'ml') was last learned. */
+int
+mac_entry_age(const struct mac_learning *ml, const struct mac_entry *e)
+{
+ time_t remaining = e->expires - time_now();
+ return ml->idle_time - remaining;
+}
static uint32_t
-mac_table_hash(const uint8_t mac[ETH_ADDR_LEN], uint16_t vlan)
+mac_table_hash(const struct mac_learning *ml, const struct eth_addr mac,
+ uint16_t vlan)
{
- return hash_bytes(mac, ETH_ADDR_LEN, vlan);
+ return hash_mac(mac, vlan, ml->secret);
}
static struct mac_entry *
-mac_entry_from_lru_node(struct list *list)
+mac_entry_from_lru_node(struct ovs_list *list)
{
return CONTAINER_OF(list, struct mac_entry, lru_node);
}
-/* Returns a tag that represents that 'mac' is on an unknown port in 'vlan'.
- * (When we learn where 'mac' is in 'vlan', this allows flows that were
- * flooded to be revalidated.) */
-static tag_type
-make_unknown_mac_tag(const struct mac_learning *ml,
- const uint8_t mac[ETH_ADDR_LEN], uint16_t vlan)
+static struct mac_entry *
+mac_entry_lookup(const struct mac_learning *ml,
+ const struct eth_addr mac, uint16_t vlan)
{
- uint32_t h = hash_int(ml->secret, mac_table_hash(mac, vlan));
- return tag_create_deterministic(h);
+ struct mac_entry *e;
+
+ HMAP_FOR_EACH_WITH_HASH (e, hmap_node, mac_table_hash(ml, mac, vlan),
+ &ml->table) {
+ if (e->vlan == vlan && eth_addr_equals(e->mac, mac)) {
+ return e;
+ }
+ }
+ return NULL;
}
-static struct list *
-mac_table_bucket(const struct mac_learning *ml,
- const uint8_t mac[ETH_ADDR_LEN],
- uint16_t vlan)
+static struct mac_learning_port *
+mac_learning_port_lookup(struct mac_learning *ml, void *port)
{
- uint32_t hash = mac_table_hash(mac, vlan);
- const struct list *list = &ml->table[hash & MAC_HASH_BITS];
- return (struct list *) list;
+ struct mac_learning_port *mlport;
+
+ HMAP_FOR_EACH_IN_BUCKET (mlport, hmap_node, hash_pointer(port, ml->secret),
+ &ml->ports_by_ptr) {
+ if (mlport->port == port) {
+ return mlport;
+ }
+ }
+ return NULL;
}
-static struct mac_entry *
-search_bucket(struct list *bucket, const uint8_t mac[ETH_ADDR_LEN],
- uint16_t vlan)
+/* Changes the client-owned pointer for entry 'e' in 'ml' to 'port'. The
+ * pointer can be retrieved with mac_entry_get_port().
+ *
+ * The MAC-learning implementation treats the data that 'port' points to as
+ * opaque and never tries to dereference it. However, when a MAC learning
+ * table becomes overfull, so that eviction is required, the implementation
+ * does first evict MAC entries for the most common 'port's values in 'ml', so
+ * that there is a degree of fairness, that is, each port is entitled to its
+ * fair share of MAC entries. */
+void
+mac_entry_set_port(struct mac_learning *ml, struct mac_entry *e, void *port)
+ OVS_REQ_WRLOCK(ml->rwlock)
{
- struct mac_entry *e;
- LIST_FOR_EACH (e, struct mac_entry, hash_node, bucket) {
- if (eth_addr_equals(e->mac, mac) && e->vlan == vlan) {
- return e;
+ if (mac_entry_get_port(ml, e) != port) {
+ ml->need_revalidate = true;
+
+ if (e->mlport) {
+ struct mac_learning_port *mlport = e->mlport;
+ list_remove(&e->port_lru_node);
+
+ if (list_is_empty(&mlport->port_lrus)) {
+ ovs_assert(mlport->heap_node.priority == 1);
+ hmap_remove(&ml->ports_by_ptr, &mlport->hmap_node);
+ heap_remove(&ml->ports_by_usage, &mlport->heap_node);
+ free(mlport);
+ } else {
+ ovs_assert(mlport->heap_node.priority > 1);
+ heap_change(&ml->ports_by_usage, &mlport->heap_node,
+ mlport->heap_node.priority - 1);
+ }
+ e->mlport = NULL;
+ }
+
+ if (port) {
+ struct mac_learning_port *mlport;
+
+ mlport = mac_learning_port_lookup(ml, port);
+ if (!mlport) {
+ mlport = xzalloc(sizeof *mlport);
+ hmap_insert(&ml->ports_by_ptr, &mlport->hmap_node,
+ hash_pointer(port, ml->secret));
+ heap_insert(&ml->ports_by_usage, &mlport->heap_node, 1);
+ mlport->port = port;
+ list_init(&mlport->port_lrus);
+ } else {
+ heap_change(&ml->ports_by_usage, &mlport->heap_node,
+ mlport->heap_node.priority + 1);
+ }
+ list_push_back(&mlport->port_lrus, &e->port_lru_node);
+ e->mlport = mlport;
}
}
- return NULL;
+}
+
+/* Finds one of the ports with the most MAC entries and evicts its least
+ * recently used entry. */
+static void
+evict_mac_entry_fairly(struct mac_learning *ml)
+ OVS_REQ_WRLOCK(ml->rwlock)
+{
+ struct mac_learning_port *mlport;
+ struct mac_entry *e;
+
+ mlport = CONTAINER_OF(heap_max(&ml->ports_by_usage),
+ struct mac_learning_port, heap_node);
+ e = CONTAINER_OF(list_front(&mlport->port_lrus),
+ struct mac_entry, port_lru_node);
+ mac_learning_expire(ml, e);
}
/* If the LRU list is not empty, stores the least-recently-used entry in '*e'
* and return false. */
static bool
get_lru(struct mac_learning *ml, struct mac_entry **e)
+ OVS_REQ_RDLOCK(ml->rwlock)
{
if (!list_is_empty(&ml->lrus)) {
*e = mac_entry_from_lru_node(ml->lrus.next);
}
}
-/* Removes 'e' from the 'ml' hash table. 'e' must not already be on the free
- * list. */
-static void
-free_mac_entry(struct mac_learning *ml, struct mac_entry *e)
+static unsigned int
+normalize_idle_time(unsigned int idle_time)
{
- list_remove(&e->hash_node);
- list_remove(&e->lru_node);
- list_push_front(&ml->free, &e->lru_node);
+ return (idle_time < 15 ? 15
+ : idle_time > 3600 ? 3600
+ : idle_time);
}
-/* Creates and returns a new MAC learning table. */
+/* Creates and returns a new MAC learning table with an initial MAC aging
+ * timeout of 'idle_time' seconds and an initial maximum of MAC_DEFAULT_MAX
+ * entries. */
struct mac_learning *
-mac_learning_create(void)
+mac_learning_create(unsigned int idle_time)
{
struct mac_learning *ml;
- int i;
ml = xmalloc(sizeof *ml);
list_init(&ml->lrus);
- list_init(&ml->free);
- for (i = 0; i < MAC_HASH_SIZE; i++) {
- list_init(&ml->table[i]);
- }
- for (i = 0; i < MAC_MAX; i++) {
- struct mac_entry *s = &ml->entries[i];
- list_push_front(&ml->free, &s->lru_node);
- }
+ hmap_init(&ml->table);
ml->secret = random_uint32();
+ ml->flood_vlans = NULL;
+ ml->idle_time = normalize_idle_time(idle_time);
+ ml->max_entries = MAC_DEFAULT_MAX;
+ ml->need_revalidate = false;
+ hmap_init(&ml->ports_by_ptr);
+ heap_init(&ml->ports_by_usage);
+ ovs_refcount_init(&ml->ref_cnt);
+ ovs_rwlock_init(&ml->rwlock);
return ml;
}
-/* Destroys MAC learning table 'ml'. */
+struct mac_learning *
+mac_learning_ref(const struct mac_learning *ml_)
+{
+ struct mac_learning *ml = CONST_CAST(struct mac_learning *, ml_);
+ if (ml) {
+ ovs_refcount_ref(&ml->ref_cnt);
+ }
+ return ml;
+}
+
+/* Unreferences (and possibly destroys) MAC learning table 'ml'. */
void
-mac_learning_destroy(struct mac_learning *ml)
+mac_learning_unref(struct mac_learning *ml)
{
- free(ml);
+ if (ml && ovs_refcount_unref(&ml->ref_cnt) == 1) {
+ struct mac_entry *e, *next;
+
+ ovs_rwlock_wrlock(&ml->rwlock);
+ HMAP_FOR_EACH_SAFE (e, next, hmap_node, &ml->table) {
+ mac_learning_expire(ml, e);
+ }
+ hmap_destroy(&ml->table);
+ hmap_destroy(&ml->ports_by_ptr);
+ heap_destroy(&ml->ports_by_usage);
+
+ bitmap_free(ml->flood_vlans);
+ ovs_rwlock_unlock(&ml->rwlock);
+ ovs_rwlock_destroy(&ml->rwlock);
+ free(ml);
+ }
}
-/* Attempts to make 'ml' learn from the fact that a frame from 'src_mac' was
- * just observed arriving from 'src_port' on the given 'vlan'.
- *
- * Returns nonzero if we actually learned something from this, zero if it just
- * confirms what we already knew. The nonzero return value is the tag of flows
- * that now need revalidation.
- *
- * The 'vlan' parameter is used to maintain separate per-VLAN learning tables.
- * Specify 0 if this behavior is undesirable. */
-tag_type
-mac_learning_learn(struct mac_learning *ml,
- const uint8_t src_mac[ETH_ADDR_LEN], uint16_t vlan,
- uint16_t src_port)
+/* Provides a bitmap of VLANs which have learning disabled, that is, VLANs on
+ * which all packets are flooded. Returns true if the set has changed from the
+ * previous value. */
+bool
+mac_learning_set_flood_vlans(struct mac_learning *ml,
+ const unsigned long *bitmap)
{
- struct mac_entry *e;
- struct list *bucket;
+ if (vlan_bitmap_equal(ml->flood_vlans, bitmap)) {
+ return false;
+ } else {
+ bitmap_free(ml->flood_vlans);
+ ml->flood_vlans = vlan_bitmap_clone(bitmap);
+ return true;
+ }
+}
+
+/* Changes the MAC aging timeout of 'ml' to 'idle_time' seconds. */
+void
+mac_learning_set_idle_time(struct mac_learning *ml, unsigned int idle_time)
+{
+ idle_time = normalize_idle_time(idle_time);
+ if (idle_time != ml->idle_time) {
+ struct mac_entry *e;
+ int delta;
- if (eth_addr_is_multicast(src_mac)) {
- static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(30, 30);
- VLOG_DBG_RL(&rl, "multicast packet source "ETH_ADDR_FMT,
- ETH_ADDR_ARGS(src_mac));
- return 0;
+ delta = (int) idle_time - (int) ml->idle_time;
+ LIST_FOR_EACH (e, lru_node, &ml->lrus) {
+ e->expires += delta;
+ }
+ ml->idle_time = idle_time;
}
+}
+
+/* Sets the maximum number of entries in 'ml' to 'max_entries', adjusting it
+ * to be within a reasonable range. */
+void
+mac_learning_set_max_entries(struct mac_learning *ml, size_t max_entries)
+{
+ ml->max_entries = (max_entries < 10 ? 10
+ : max_entries > 1000 * 1000 ? 1000 * 1000
+ : max_entries);
+}
- bucket = mac_table_bucket(ml, src_mac, vlan);
- e = search_bucket(bucket, src_mac, vlan);
+static bool
+is_learning_vlan(const struct mac_learning *ml, uint16_t vlan)
+{
+ return !ml->flood_vlans || !bitmap_is_set(ml->flood_vlans, vlan);
+}
+
+/* Returns true if 'src_mac' may be learned on 'vlan' for 'ml'.
+ * Returns false if 'ml' is NULL, if src_mac is not valid for learning, or if
+ * 'vlan' is configured on 'ml' to flood all packets. */
+bool
+mac_learning_may_learn(const struct mac_learning *ml,
+ const struct eth_addr src_mac, uint16_t vlan)
+{
+ return ml && is_learning_vlan(ml, vlan) && !eth_addr_is_multicast(src_mac);
+}
+
+/* Searches 'ml' for and returns a MAC learning entry for 'src_mac' in 'vlan',
+ * inserting a new entry if necessary. The caller must have already verified,
+ * by calling mac_learning_may_learn(), that 'src_mac' and 'vlan' are
+ * learnable.
+ *
+ * If the returned MAC entry is new (that is, if it has a NULL client-provided
+ * port, as returned by mac_entry_get_port()), then the caller must initialize
+ * the new entry's port to a nonnull value with mac_entry_set_port(). */
+struct mac_entry *
+mac_learning_insert(struct mac_learning *ml,
+ const struct eth_addr src_mac, uint16_t vlan)
+{
+ struct mac_entry *e;
+
+ e = mac_entry_lookup(ml, src_mac, vlan);
if (!e) {
- if (!list_is_empty(&ml->free)) {
- e = mac_entry_from_lru_node(ml->free.next);
- } else {
- e = mac_entry_from_lru_node(ml->lrus.next);
- list_remove(&e->hash_node);
+ uint32_t hash = mac_table_hash(ml, src_mac, vlan);
+
+ if (hmap_count(&ml->table) >= ml->max_entries) {
+ evict_mac_entry_fairly(ml);
}
- memcpy(e->mac, src_mac, ETH_ADDR_LEN);
- list_push_front(bucket, &e->hash_node);
- e->port = -1;
+
+ e = xmalloc(sizeof *e);
+ hmap_insert(&ml->table, &e->hmap_node, hash);
+ e->mac = src_mac;
e->vlan = vlan;
- e->tag = make_unknown_mac_tag(ml, src_mac, vlan);
+ e->grat_arp_lock = TIME_MIN;
+ e->mlport = NULL;
+ COVERAGE_INC(mac_learning_learned);
+ } else {
+ list_remove(&e->lru_node);
}
- /* Make the entry most-recently-used. */
- list_remove(&e->lru_node);
+ /* Mark 'e' as recently used. */
list_push_back(&ml->lrus, &e->lru_node);
- e->expires = time_now() + 60;
-
- /* Did we learn something? */
- if (e->port != src_port) {
- tag_type old_tag = e->tag;
- e->port = src_port;
- e->tag = tag_create_random();
- COVERAGE_INC(mac_learning_learned);
- return old_tag;
+ if (e->mlport) {
+ list_remove(&e->port_lru_node);
+ list_push_back(&e->mlport->port_lrus, &e->port_lru_node);
}
- return 0;
-}
+ e->expires = time_now() + ml->idle_time;
-/* Looks up MAC 'dst' for VLAN 'vlan' in 'ml'. Returns the port on which a
- * frame destined for 'dst' should be sent, -1 if unknown. */
-int
-mac_learning_lookup(const struct mac_learning *ml,
- const uint8_t dst[ETH_ADDR_LEN], uint16_t vlan)
-{
- tag_type tag = 0;
- return mac_learning_lookup_tag(ml, dst, vlan, &tag);
+ return e;
}
-/* Looks up MAC 'dst' for VLAN 'vlan' in 'ml'. Returns the port on which a
- * frame destined for 'dst' should be sent, -1 if unknown.
- *
- * Adds to '*tag' (which the caller must have initialized) the tag that should
- * be attached to any flow created based on the return value, if any, to allow
- * those flows to be revalidated when the MAC learning entry changes. */
-int
-mac_learning_lookup_tag(const struct mac_learning *ml,
- const uint8_t dst[ETH_ADDR_LEN], uint16_t vlan,
- tag_type *tag)
+/* Looks up MAC 'dst' for VLAN 'vlan' in 'ml' and returns the associated MAC
+ * learning entry, if any. */
+struct mac_entry *
+mac_learning_lookup(const struct mac_learning *ml,
+ const struct eth_addr dst, uint16_t vlan)
{
if (eth_addr_is_multicast(dst)) {
- return -1;
+ /* No tag because the treatment of multicast destinations never
+ * changes. */
+ return NULL;
+ } else if (!is_learning_vlan(ml, vlan)) {
+ /* We don't tag this property. The set of learning VLANs changes so
+ * rarely that we revalidate every flow when it changes. */
+ return NULL;
} else {
- struct mac_entry *e = search_bucket(mac_table_bucket(ml, dst, vlan),
- dst, vlan);
- if (e) {
- *tag |= e->tag;
- return e->port;
- } else {
- *tag |= make_unknown_mac_tag(ml, dst, vlan);
- return -1;
- }
+ struct mac_entry *e = mac_entry_lookup(ml, dst, vlan);
+
+ ovs_assert(e == NULL || mac_entry_get_port(ml, e) != NULL);
+ return e;
}
}
-/* Expires all the mac-learning entries in 'ml'. The tags in 'ml' are
- * discarded, so the client is responsible for revalidating any flows that
- * depend on 'ml', if necessary. */
+/* Expires 'e' from the 'ml' hash table. */
+void
+mac_learning_expire(struct mac_learning *ml, struct mac_entry *e)
+{
+ ml->need_revalidate = true;
+ mac_entry_set_port(ml, e, NULL);
+ hmap_remove(&ml->table, &e->hmap_node);
+ list_remove(&e->lru_node);
+ free(e);
+}
+
+/* Expires all the mac-learning entries in 'ml'. */
void
mac_learning_flush(struct mac_learning *ml)
{
struct mac_entry *e;
while (get_lru(ml, &e)){
- free_mac_entry(ml, e);
+ mac_learning_expire(ml, e);
}
+ hmap_shrink(&ml->table);
}
-void
-mac_learning_run(struct mac_learning *ml, struct tag_set *set)
+/* Does periodic work required by 'ml'. Returns true if something changed that
+ * may require flow revalidation. */
+bool
+mac_learning_run(struct mac_learning *ml)
{
+ bool need_revalidate;
struct mac_entry *e;
- while (get_lru(ml, &e) && time_now() >= e->expires) {
+
+ while (get_lru(ml, &e)
+ && (hmap_count(&ml->table) > ml->max_entries
+ || time_now() >= e->expires)) {
COVERAGE_INC(mac_learning_expired);
- if (set) {
- tag_set_add(set, e->tag);
- }
- free_mac_entry(ml, e);
+ mac_learning_expire(ml, e);
}
+
+ need_revalidate = ml->need_revalidate;
+ ml->need_revalidate = false;
+ return need_revalidate;
}
void
mac_learning_wait(struct mac_learning *ml)
{
- if (!list_is_empty(&ml->lrus)) {
+ if (hmap_count(&ml->table) > ml->max_entries
+ || ml->need_revalidate) {
+ poll_immediate_wake();
+ } else if (!list_is_empty(&ml->lrus)) {
struct mac_entry *e = mac_entry_from_lru_node(ml->lrus.next);
- poll_timer_wait((e->expires - time_now()) * 1000);
+ poll_timer_wait_until(e->expires * 1000LL);
}
}
projects / cascardo / ovs.git / blobdiff