mac-learning: Reference count 'struct mac_learning".

[sliver-openvswitch.git] / lib / mac-learning.c

diff --git a/lib/mac-learning.c b/lib/mac-learning.c
index 68fc621..ca0ccb8 100644 (file)
--- a/lib/mac-learning.c
+++ b/lib/mac-learning.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,7 +17,6 @@
 #include <config.h>
 #include "mac-learning.h"
 
-#include <assert.h>
 #include <inttypes.h>
 #include <stdlib.h>
 
@@ -110,7 +109,8 @@ normalize_idle_time(unsigned int idle_time)
 }
 
 /* Creates and returns a new MAC learning table with an initial MAC aging
- * timeout of 'idle_time' seconds. */
+ * timeout of 'idle_time' seconds and an initial maximum of MAC_DEFAULT_MAX
+ * entries. */
 struct mac_learning *
 mac_learning_create(unsigned int idle_time)
 {
@@ -122,14 +122,33 @@ mac_learning_create(unsigned int idle_time)
     ml->secret = random_uint32();
     ml->flood_vlans = NULL;
     ml->idle_time = normalize_idle_time(idle_time);
+    ml->max_entries = MAC_DEFAULT_MAX;
+    tag_set_init(&ml->tags);
+    ml->ref_cnt = 1;
     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_assert(ml->ref_cnt > 0);
+        ml->ref_cnt++;
+    }
+    return ml;
+}
+
+/* Unreferences (and possibly destroys) MAC learning table 'ml'. */
+void
+mac_learning_unref(struct mac_learning *ml)
+{
+    if (!ml) {
+        return;
+    }
+
+    ovs_assert(ml->ref_cnt > 0);
+    if (!--ml->ref_cnt) {
         struct mac_entry *e, *next;
 
         HMAP_FOR_EACH_SAFE (e, next, hmap_node, &ml->table) {
@@ -176,6 +195,16 @@ mac_learning_set_idle_time(struct mac_learning *ml, unsigned int 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);
+}
+
 static bool
 is_learning_vlan(const struct mac_learning *ml, uint16_t vlan)
 {
@@ -212,7 +241,7 @@ mac_learning_insert(struct mac_learning *ml,
     if (!e) {
         uint32_t hash = mac_table_hash(ml, src_mac, vlan);
 
-        if (hmap_count(&ml->table) >= MAC_MAX) {
+        if (hmap_count(&ml->table) >= ml->max_entries) {
             get_lru(ml, &e);
             mac_learning_expire(ml, e);
         }
@@ -234,22 +263,23 @@ mac_learning_insert(struct mac_learning *ml,
     return e;
 }
 
-/* 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.)
+/* 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. */
-tag_type
+void
 mac_learning_changed(struct mac_learning *ml, struct mac_entry *e)
 {
-    tag_type old_tag = e->tag;
+    tag_type tag = e->tag ? e->tag : make_unknown_mac_tag(ml, e->mac, e->vlan);
 
     COVERAGE_INC(mac_learning_learned);
 
     e->tag = tag_create_random();
-    return old_tag ? old_tag : make_unknown_mac_tag(ml, e->mac, e->vlan);
+    tag_set_add(&ml->tags, tag);
 }
 
 /* Looks up MAC 'dst' for VLAN 'vlan' in 'ml' and returns the associated MAC
@@ -272,7 +302,7 @@ mac_learning_lookup(const struct mac_learning *ml,
     } else {
         struct mac_entry *e = mac_entry_lookup(ml, dst, vlan);
 
-        assert(e == NULL || e->tag != 0);
+        ovs_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);
@@ -311,7 +341,15 @@ void
 mac_learning_run(struct mac_learning *ml, struct tag_set *set)
 {
     struct mac_entry *e;
-    while (get_lru(ml, &e) && time_now() >= e->expires) {
+
+    if (set) {
+        tag_set_union(set, &ml->tags);
+    }
+    tag_set_init(&ml->tags);
+
+    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);
@@ -323,7 +361,10 @@ mac_learning_run(struct mac_learning *ml, struct tag_set *set)
 void
 mac_learning_wait(struct mac_learning *ml)
 {
-    if (!list_is_empty(&ml->lrus)) {
+    if (hmap_count(&ml->table) > ml->max_entries
+        || !tag_set_is_empty(&ml->tags)) {
+        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_until(e->expires * 1000LL);
     }