/*
- * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 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 "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' was last learned. */
+/* Returns the number of seconds since 'e' (within 'ml') was last learned. */
int
-mac_entry_age(const struct mac_entry *e)
+mac_entry_age(const struct mac_learning *ml, const struct mac_entry *e)
{
time_t remaining = e->expires - time_now();
- return MAC_ENTRY_IDLE_TIME - remaining;
+ 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 uint8_t mac[ETH_ADDR_LEN],
+ uint16_t vlan)
{
- return hash_bytes(mac, ETH_ADDR_LEN, vlan);
+ return hash_mac(mac, vlan, ml->secret);
}
static struct mac_entry *
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)
-{
- uint32_t h = hash_int(ml->secret, mac_table_hash(mac, vlan));
- return tag_create_deterministic(h);
-}
-
-static struct list *
-mac_table_bucket(const struct mac_learning *ml,
- const uint8_t mac[ETH_ADDR_LEN],
- uint16_t vlan)
-{
- uint32_t hash = mac_table_hash(mac, vlan);
- const struct list *list = &ml->table[hash & MAC_HASH_BITS];
- return (struct list *) list;
-}
-
static struct mac_entry *
-search_bucket(struct list *bucket, const uint8_t mac[ETH_ADDR_LEN],
- uint16_t vlan)
+mac_entry_lookup(const struct mac_learning *ml,
+ const uint8_t mac[ETH_ADDR_LEN], uint16_t vlan)
{
struct mac_entry *e;
- LIST_FOR_EACH (e, struct mac_entry, hash_node, bucket) {
- if (eth_addr_equals(e->mac, mac) && e->vlan == vlan) {
+
+ 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;
}
}
* 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;
+ ovs_refcount_init(&ml->ref_cnt);
+ ovs_rwlock_init(&ml->rwlock);
return ml;
}
-/* Destroys MAC learning table 'ml'. */
-void
-mac_learning_destroy(struct mac_learning *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_unref(struct mac_learning *ml)
+{
+ if (ml && ovs_refcount_unref(&ml->ref_cnt) == 1) {
+ struct mac_entry *e, *next;
+
+ HMAP_FOR_EACH_SAFE (e, next, hmap_node, &ml->table) {
+ hmap_remove(&ml->table, &e->hmap_node);
+ free(e);
+ }
+ hmap_destroy(&ml->table);
+
bitmap_free(ml->flood_vlans);
+ ovs_rwlock_destroy(&ml->rwlock);
+ free(ml);
}
- free(ml);
}
/* Provides a bitmap of VLANs which have learning disabled, that is, VLANs on
- * which all packets are flooded. It takes ownership of the bitmap. Returns
- * true if the set has changed from the previous value. */
+ * 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, unsigned long *bitmap)
+mac_learning_set_flood_vlans(struct mac_learning *ml,
+ const unsigned long *bitmap)
+{
+ 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)
{
- bool ret = (bitmap == NULL
- ? ml->flood_vlans != NULL
- : (ml->flood_vlans == NULL
- || !bitmap_equal(bitmap, ml->flood_vlans, 4096)));
+ idle_time = normalize_idle_time(idle_time);
+ if (idle_time != ml->idle_time) {
+ struct mac_entry *e;
+ int delta;
- bitmap_free(ml->flood_vlans);
- ml->flood_vlans = bitmap;
+ delta = (int) idle_time - (int) ml->idle_time;
+ LIST_FOR_EACH (e, lru_node, &ml->lrus) {
+ e->expires += delta;
+ }
+ ml->idle_time = idle_time;
+ }
+}
- return ret;
+/* 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);
}
static bool
is_learning_vlan(const struct mac_learning *ml, uint16_t vlan)
{
- return !(ml->flood_vlans && bitmap_is_set(ml->flood_vlans, vlan));
+ return !ml->flood_vlans || !bitmap_is_set(ml->flood_vlans, vlan);
}
-/* 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.
+/* 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 uint8_t src_mac[ETH_ADDR_LEN], 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.
*
- * 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)
+ * If the returned MAC entry is new (as may be determined by calling
+ * mac_entry_is_new()), then the caller must pass the new entry to
+ * mac_learning_changed(). The caller must also initialize the new entry's
+ * 'port' member. Otherwise calling those functions is at the caller's
+ * discretion. */
+struct mac_entry *
+mac_learning_insert(struct mac_learning *ml,
+ const uint8_t src_mac[ETH_ADDR_LEN], uint16_t vlan)
{
struct mac_entry *e;
- struct list *bucket;
- if (!is_learning_vlan(ml, vlan)) {
- return 0;
- }
-
- 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;
- }
-
- bucket = mac_table_bucket(ml, src_mac, vlan);
- e = search_bucket(bucket, src_mac, vlan);
+ 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) {
+ get_lru(ml, &e);
+ mac_learning_expire(ml, e);
}
+
+ e = xmalloc(sizeof *e);
+ hmap_insert(&ml->table, &e->hmap_node, hash);
memcpy(e->mac, src_mac, ETH_ADDR_LEN);
- list_push_front(bucket, &e->hash_node);
- e->port = -1;
e->vlan = vlan;
- e->tag = make_unknown_mac_tag(ml, src_mac, vlan);
+ e->grat_arp_lock = TIME_MIN;
+ e->port.p = NULL;
+ } 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() + MAC_ENTRY_IDLE_TIME;
-
- /* 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;
- }
- return 0;
+ e->expires = time_now() + ml->idle_time;
+
+ 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. */
-int
-mac_learning_lookup(const struct mac_learning *ml,
- const uint8_t dst[ETH_ADDR_LEN], uint16_t vlan)
+/* Changes 'e''s tag to a new, randomly selected one. Causes
+ * mac_learning_run() to flag for revalidation the tag that would have been
+ * previously used for this entry's MAC and VLAN (either before 'e' was
+ * inserted, if it is new, or otherwise before its port was updated.)
+ *
+ * The client should call this function after obtaining a MAC learning entry
+ * from mac_learning_insert(), if the entry is either new or if its learned
+ * port has changed. */
+void
+mac_learning_changed(struct mac_learning *ml)
{
- tag_type tag = 0;
- return mac_learning_lookup_tag(ml, dst, vlan, &tag);
+ COVERAGE_INC(mac_learning_learned);
+ ml->need_revalidate = true;
}
-/* 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. If 'tag' is nonnull, then the tag that associates
+ * 'dst' and 'vlan' with its currently learned port will be OR'd into
+ * '*tag'. */
+struct mac_entry *
+mac_learning_lookup(const struct mac_learning *ml,
+ const uint8_t dst[ETH_ADDR_LEN], uint16_t vlan)
{
- if (eth_addr_is_multicast(dst) || !is_learning_vlan(ml, vlan)) {
- return -1;
+ if (eth_addr_is_multicast(dst)) {
+ /* 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 || e->port.p != 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)
+{
+ hmap_remove(&ml->table, &e->hmap_node);
+ list_remove(&e->lru_node);
+ free(e);
+}
+
+/* Expires all the mac-learning entries in 'ml'. If not NULL, the tags in 'ml'
+ * are added to 'tags'. Otherwise the tags in 'ml' are discarded. The client
+ * is responsible for revalidating any flows that depend on 'ml', if
+ * necessary. */
void
mac_learning_flush(struct mac_learning *ml)
{
struct mac_entry *e;
while (get_lru(ml, &e)){
- free_mac_entry(ml, e);
+ ml->need_revalidate = true;
+ 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);
+ ml->need_revalidate = true;
+ 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);
}
}
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