/*
- * Copyright (c) 2008, 2009 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
*
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
+ * 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:
*
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ * 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 <config.h>
#include <inttypes.h>
#include <stdlib.h>
+#include "bitmap.h"
#include "coverage.h"
#include "hash.h"
#include "list.h"
#include "tag.h"
#include "timeval.h"
#include "util.h"
-
-#define THIS_MODULE VLM_mac_learning
#include "vlog.h"
-#define MAC_HASH_BITS 10
-#define MAC_HASH_MASK (MAC_HASH_SIZE - 1)
-#define MAC_HASH_SIZE (1u << MAC_HASH_BITS)
-
-#define MAC_MAX 1024
-
-/* A MAC learning table entry. */
-struct mac_entry {
- struct list hash_node; /* Element in a mac_learning 'table' list. */
- struct list lru_node; /* Element in 'lrus' or 'free' list. */
- time_t expires; /* Expiration time. */
- uint8_t mac[ETH_ADDR_LEN]; /* Known MAC address. */
- uint16_t vlan; /* VLAN tag. */
- int port; /* Port on which MAC was most recently seen. */
- tag_type tag; /* Tag for this learning entry. */
-};
-
-/* MAC learning table. */
-struct mac_learning {
- struct list free; /* Not-in-use entries. */
- struct list lrus; /* In-use entries, least recently used at the
- front, most recently used at the back. */
- struct list table[MAC_HASH_SIZE]; /* Hash table. */
- struct mac_entry entries[MAC_MAX]; /* All entries. */
- uint32_t secret; /* Secret for */
-};
+VLOG_DEFINE_THIS_MODULE(mac_learning);
+
+COVERAGE_DEFINE(mac_learning_learned);
+COVERAGE_DEFINE(mac_learning_expired);
+
+/* Returns the number of seconds since 'e' was last learned. */
+int
+mac_entry_age(const struct mac_entry *e)
+{
+ time_t remaining = e->expires - time_now();
+ return MAC_ENTRY_IDLE_TIME - remaining;
+}
static uint32_t
mac_table_hash(const uint8_t mac[ETH_ADDR_LEN], uint16_t vlan)
uint16_t vlan)
{
uint32_t hash = mac_table_hash(mac, vlan);
- const struct list *list = &ml->table[hash & MAC_HASH_BITS];
+ const struct list *list = &ml->table[hash & MAC_HASH_MASK];
return (struct list *) list;
}
uint16_t vlan)
{
struct mac_entry *e;
- LIST_FOR_EACH (e, struct mac_entry, hash_node, bucket) {
+ LIST_FOR_EACH (e, hash_node, bucket) {
if (eth_addr_equals(e->mac, mac) && e->vlan == vlan) {
return e;
}
}
}
-/* 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)
-{
- list_remove(&e->hash_node);
- list_remove(&e->lru_node);
- list_push_front(&ml->free, &e->lru_node);
-}
-
/* Creates and returns a new MAC learning table. */
struct mac_learning *
mac_learning_create(void)
list_push_front(&ml->free, &s->lru_node);
}
ml->secret = random_uint32();
+ ml->flood_vlans = NULL;
return ml;
}
void
mac_learning_destroy(struct mac_learning *ml)
{
+ if (ml) {
+ bitmap_free(ml->flood_vlans);
+ }
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.
+/* 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. */
+bool
+mac_learning_set_flood_vlans(struct mac_learning *ml, unsigned long *bitmap)
+{
+ bool ret = (bitmap == NULL
+ ? ml->flood_vlans != NULL
+ : (ml->flood_vlans == NULL
+ || !bitmap_equal(bitmap, ml->flood_vlans, 4096)));
+
+ bitmap_free(ml->flood_vlans);
+ ml->flood_vlans = bitmap;
+
+ return ret;
+}
+
+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 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 (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);
if (!e) {
e = mac_entry_from_lru_node(ml->lrus.next);
list_remove(&e->hash_node);
}
- memcpy(e->mac, src_mac, ETH_ADDR_LEN);
list_push_front(bucket, &e->hash_node);
- e->port = -1;
+ memcpy(e->mac, src_mac, ETH_ADDR_LEN);
e->vlan = vlan;
- e->tag = make_unknown_mac_tag(ml, src_mac, vlan);
+ e->tag = 0;
+ e->grat_arp_lock = TIME_MIN;
}
- /* Make the entry most-recently-used. */
+ /* Mark 'e' as recently used. */
list_remove(&e->lru_node);
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;
- }
- return 0;
+ e->expires = time_now() + MAC_ENTRY_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, and returns 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. */
+tag_type
+mac_learning_changed(struct mac_learning *ml, struct mac_entry *e)
{
- tag_type tag = 0;
- return mac_learning_lookup_tag(ml, dst, vlan, &tag);
+ tag_type old_tag = e->tag;
+
+ COVERAGE_INC(mac_learning_learned);
+
+ e->tag = tag_create_random();
+ return old_tag ? old_tag : make_unknown_mac_tag(ml, e->mac, e->vlan);
}
-/* 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,
+ tag_type *tag)
{
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;
+ assert(e == NULL || e->tag != 0);
+ if (tag) {
+ /* Tag either the learned port or the lack thereof. */
+ *tag |= e ? e->tag : make_unknown_mac_tag(ml, dst, vlan);
}
+ return e;
}
}
+/* Expires 'e' from the 'ml' hash table. 'e' must not already be on the free
+ * list. */
+void
+mac_learning_expire(struct mac_learning *ml, struct mac_entry *e)
+{
+ list_remove(&e->hash_node);
+ list_remove(&e->lru_node);
+ list_push_front(&ml->free, &e->lru_node);
+}
+
/* 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. */
{
struct mac_entry *e;
while (get_lru(ml, &e)){
- free_mac_entry(ml, e);
+ mac_learning_expire(ml, e);
}
}
if (set) {
tag_set_add(set, e->tag);
}
- free_mac_entry(ml, e);
+ mac_learning_expire(ml, e);
}
}
{
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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