X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fmac-learning.c;h=3c541af2bbd846f3e8fbc34fc01098f1695f971f;hb=e0edde6fee279cdbbf3c179f5f50adaf0c7c7f1e;hp=f9859b6b0eb75d9fc9f41ed784482c8a26a4e046;hpb=7cf8b2660f9813fe080a3f4fcc975099cb36417a;p=sliver-openvswitch.git

diff --git a/lib/mac-learning.c b/lib/mac-learning.c
index f9859b6b0..3c541af2b 100644
--- a/lib/mac-learning.c
+++ b/lib/mac-learning.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010 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.
@@ -28,23 +28,31 @@
 #include "poll-loop.h"
 #include "tag.h"
 #include "timeval.h"
+#include "unaligned.h"
 #include "util.h"
-
-#define THIS_MODULE VLM_mac_learning
+#include "vlan-bitmap.h"
 #include "vlog.h"
 
-/* Returns the number of seconds since 'e' was last learned. */
+VLOG_DEFINE_THIS_MODULE(mac_learning);
+
+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_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);
+    unsigned int mac1 = get_unaligned_u32((uint32_t *) mac);
+    unsigned int mac2 = get_unaligned_u16((uint16_t *) (mac + 4));
+    return hash_3words(mac1, mac2 | (vlan << 16), ml->secret);
 }
 
 static struct mac_entry *
@@ -60,27 +68,18 @@ 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;
+    return tag_create_deterministic(mac_table_hash(ml, mac, vlan));
 }
 
 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;
         }
     }
@@ -102,35 +101,27 @@ get_lru(struct mac_learning *ml, struct mac_entry **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)
+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. */
 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);
     return ml;
 }
 
@@ -139,140 +130,181 @@ void
 mac_learning_destroy(struct mac_learning *ml)
 {
     if (ml) {
+        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);
+        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)
 {
-    bool ret = (bitmap == NULL
-                ? ml->flood_vlans != NULL
-                : (ml->flood_vlans == NULL
-                   || !bitmap_equal(bitmap, ml->flood_vlans, 4096)));
+    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;
+    }
+}
 
-    bitmap_free(ml->flood_vlans);
-    ml->flood_vlans = bitmap;
+/* 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;
 
-    return ret;
+        delta = (int) idle_time - (int) ml->idle_time;
+        LIST_FOR_EACH (e, lru_node, &ml->lrus) {
+            e->expires += delta;
+        }
+        ml->idle_time = idle_time;
+    }
 }
 
 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) >= MAC_MAX) {
+            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->tag = 0;
+        e->grat_arp_lock = TIME_MIN;
+    } 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, 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) || !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);
+
+        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 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_flush(struct mac_learning *ml)
+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 tag_set *tags)
 {
     struct mac_entry *e;
     while (get_lru(ml, &e)){
-        free_mac_entry(ml, e);
+        if (tags) {
+            tag_set_add(tags, e->tag);
+        }
+        mac_learning_expire(ml, e);
     }
+    hmap_shrink(&ml->table);
 }
 
 void
@@ -284,7 +316,7 @@ mac_learning_run(struct mac_learning *ml, struct tag_set *set)
         if (set) {
             tag_set_add(set, e->tag);
         }
-        free_mac_entry(ml, e);
+        mac_learning_expire(ml, e);
     }
 }