bridge: Fix RCU race in br_multicast_stop
[safe/jmp/linux-2.6] / net / bridge / br_fdb.c
index 24396b9..3b8e038 100644 (file)
@@ -5,8 +5,6 @@
  *     Authors:
  *     Lennert Buytenhek               <buytenh@gnu.org>
  *
- *     $Id: br_fdb.c,v 1.6 2002/01/17 00:57:07 davem Exp $
- *
  *     This program is free software; you can redistribute it and/or
  *     modify it under the terms of the GNU General Public License
  *     as published by the Free Software Foundation; either version
 
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/rculist.h>
 #include <linux/spinlock.h>
 #include <linux/times.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/jhash.h>
+#include <linux/random.h>
 #include <asm/atomic.h>
+#include <asm/unaligned.h>
 #include "br_private.h"
 
-static kmem_cache_t *br_fdb_cache __read_mostly;
+static struct kmem_cache *br_fdb_cache __read_mostly;
 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
                      const unsigned char *addr);
 
-void __init br_fdb_init(void)
+static u32 fdb_salt __read_mostly;
+
+int __init br_fdb_init(void)
 {
        br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
                                         sizeof(struct net_bridge_fdb_entry),
                                         0,
-                                        SLAB_HWCACHE_ALIGN, NULL, NULL);
+                                        SLAB_HWCACHE_ALIGN, NULL);
+       if (!br_fdb_cache)
+               return -ENOMEM;
+
+       get_random_bytes(&fdb_salt, sizeof(fdb_salt));
+       return 0;
 }
 
-void __exit br_fdb_fini(void)
+void br_fdb_fini(void)
 {
        kmem_cache_destroy(br_fdb_cache);
 }
@@ -44,34 +52,43 @@ void __exit br_fdb_fini(void)
 /* if topology_changing then use forward_delay (default 15 sec)
  * otherwise keep longer (default 5 minutes)
  */
-static __inline__ unsigned long hold_time(const struct net_bridge *br)
+static inline unsigned long hold_time(const struct net_bridge *br)
 {
        return br->topology_change ? br->forward_delay : br->ageing_time;
 }
 
-static __inline__ int has_expired(const struct net_bridge *br,
+static inline int has_expired(const struct net_bridge *br,
                                  const struct net_bridge_fdb_entry *fdb)
 {
-       return !fdb->is_static 
-               && time_before_eq(fdb->ageing_timer + hold_time(br), jiffies);
+       return !fdb->is_static &&
+               time_before_eq(fdb->ageing_timer + hold_time(br), jiffies);
 }
 
-static __inline__ int br_mac_hash(const unsigned char *mac)
+static inline int br_mac_hash(const unsigned char *mac)
 {
-       return jhash(mac, ETH_ALEN, 0) & (BR_HASH_SIZE - 1);
+       /* use 1 byte of OUI cnd 3 bytes of NIC */
+       u32 key = get_unaligned((u32 *)(mac + 2));
+       return jhash_1word(key, fdb_salt) & (BR_HASH_SIZE - 1);
 }
 
-static __inline__ void fdb_delete(struct net_bridge_fdb_entry *f)
+static void fdb_rcu_free(struct rcu_head *head)
+{
+       struct net_bridge_fdb_entry *ent
+               = container_of(head, struct net_bridge_fdb_entry, rcu);
+       kmem_cache_free(br_fdb_cache, ent);
+}
+
+static inline void fdb_delete(struct net_bridge_fdb_entry *f)
 {
        hlist_del_rcu(&f->hlist);
-       br_fdb_put(f);
+       call_rcu(&f->rcu, fdb_rcu_free);
 }
 
 void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
 {
        struct net_bridge *br = p->br;
        int i;
-       
+
        spin_lock_bh(&br->hash_lock);
 
        /* Search all chains since old address/hash is unknown */
@@ -85,9 +102,9 @@ void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
                                /* maybe another port has same hw addr? */
                                struct net_bridge_port *op;
                                list_for_each_entry(op, &br->port_list, list) {
-                                       if (op != p && 
-                                           !memcmp(op->dev->dev_addr,
-                                                   f->addr.addr, ETH_ALEN)) {
+                                       if (op != p &&
+                                           !compare_ether_addr(op->dev->dev_addr,
+                                                               f->addr.addr)) {
                                                f->dst = op;
                                                goto insert;
                                        }
@@ -110,6 +127,7 @@ void br_fdb_cleanup(unsigned long _data)
 {
        struct net_bridge *br = (struct net_bridge *)_data;
        unsigned long delay = hold_time(br);
+       unsigned long next_timer = jiffies + br->forward_delay;
        int i;
 
        spin_lock_bh(&br->hash_lock);
@@ -118,30 +136,61 @@ void br_fdb_cleanup(unsigned long _data)
                struct hlist_node *h, *n;
 
                hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
-                       if (!f->is_static && 
-                           time_before_eq(f->ageing_timer + delay, jiffies)) 
+                       unsigned long this_timer;
+                       if (f->is_static)
+                               continue;
+                       this_timer = f->ageing_timer + delay;
+                       if (time_before_eq(this_timer, jiffies))
                                fdb_delete(f);
+                       else if (time_before(this_timer, next_timer))
+                               next_timer = this_timer;
                }
        }
        spin_unlock_bh(&br->hash_lock);
 
-       mod_timer(&br->gc_timer, jiffies + HZ/10);
+       /* Add HZ/4 to ensure we round the jiffies upwards to be after the next
+        * timer, otherwise we might round down and will have no-op run. */
+       mod_timer(&br->gc_timer, round_jiffies(next_timer + HZ/4));
+}
+
+/* Completely flush all dynamic entries in forwarding database.*/
+void br_fdb_flush(struct net_bridge *br)
+{
+       int i;
+
+       spin_lock_bh(&br->hash_lock);
+       for (i = 0; i < BR_HASH_SIZE; i++) {
+               struct net_bridge_fdb_entry *f;
+               struct hlist_node *h, *n;
+               hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
+                       if (!f->is_static)
+                               fdb_delete(f);
+               }
+       }
+       spin_unlock_bh(&br->hash_lock);
 }
 
-void br_fdb_delete_by_port(struct net_bridge *br, struct net_bridge_port *p)
+/* Flush all entries refering to a specific port.
+ * if do_all is set also flush static entries
+ */
+void br_fdb_delete_by_port(struct net_bridge *br,
+                          const struct net_bridge_port *p,
+                          int do_all)
 {
        int i;
 
        spin_lock_bh(&br->hash_lock);
        for (i = 0; i < BR_HASH_SIZE; i++) {
                struct hlist_node *h, *g;
-               
+
                hlist_for_each_safe(h, g, &br->hash[i]) {
                        struct net_bridge_fdb_entry *f
                                = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
-                       if (f->dst != p) 
+                       if (f->dst != p)
                                continue;
 
+                       if (f->is_static && !do_all)
+                               continue;
                        /*
                         * if multiple ports all have the same device address
                         * then when one port is deleted, assign
@@ -150,9 +199,9 @@ void br_fdb_delete_by_port(struct net_bridge *br, struct net_bridge_port *p)
                        if (f->is_local) {
                                struct net_bridge_port *op;
                                list_for_each_entry(op, &br->port_list, list) {
-                                       if (op != p && 
-                                           !memcmp(op->dev->dev_addr,
-                                                   f->addr.addr, ETH_ALEN)) {
+                                       if (op != p &&
+                                           !compare_ether_addr(op->dev->dev_addr,
+                                                               f->addr.addr)) {
                                                f->dst = op;
                                                goto skip_delete;
                                        }
@@ -174,7 +223,7 @@ struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
        struct net_bridge_fdb_entry *fdb;
 
        hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) {
-               if (!memcmp(fdb->addr.addr, addr, ETH_ALEN)) {
+               if (!compare_ether_addr(fdb->addr.addr, addr)) {
                        if (unlikely(has_expired(br, fdb)))
                                break;
                        return fdb;
@@ -184,36 +233,29 @@ struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
        return NULL;
 }
 
-/* Interface used by ATM hook that keeps a ref count */
-struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br, 
-                                       unsigned char *addr)
+#if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE)
+/* Interface used by ATM LANE hook to test
+ * if an addr is on some other bridge port */
+int br_fdb_test_addr(struct net_device *dev, unsigned char *addr)
 {
        struct net_bridge_fdb_entry *fdb;
+       int ret;
+
+       if (!dev->br_port)
+               return 0;
 
        rcu_read_lock();
-       fdb = __br_fdb_get(br, addr);
-       if (fdb) 
-               atomic_inc(&fdb->use_count);
+       fdb = __br_fdb_get(dev->br_port->br, addr);
+       ret = fdb && fdb->dst->dev != dev &&
+               fdb->dst->state == BR_STATE_FORWARDING;
        rcu_read_unlock();
-       return fdb;
-}
-
-static void fdb_rcu_free(struct rcu_head *head)
-{
-       struct net_bridge_fdb_entry *ent
-               = container_of(head, struct net_bridge_fdb_entry, rcu);
-       kmem_cache_free(br_fdb_cache, ent);
-}
 
-/* Set entry up for deletion with RCU  */
-void br_fdb_put(struct net_bridge_fdb_entry *ent)
-{
-       if (atomic_dec_and_test(&ent->use_count))
-               call_rcu(&ent->rcu, fdb_rcu_free);
+       return ret;
 }
+#endif /* CONFIG_ATM_LANE */
 
 /*
- * Fill buffer with forwarding table records in 
+ * Fill buffer with forwarding table records in
  * the API format.
  */
 int br_fdb_fillbuf(struct net_bridge *br, void *buf,
@@ -232,7 +274,7 @@ int br_fdb_fillbuf(struct net_bridge *br, void *buf,
                        if (num >= maxnum)
                                goto out;
 
-                       if (has_expired(br, f)) 
+                       if (has_expired(br, f))
                                continue;
 
                        if (skip) {
@@ -242,7 +284,11 @@ int br_fdb_fillbuf(struct net_bridge *br, void *buf,
 
                        /* convert from internal format to API */
                        memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
+
+                       /* due to ABI compat need to split into hi/lo */
                        fe->port_no = f->dst->port_no;
+                       fe->port_hi = f->dst->port_no >> 8;
+
                        fe->is_local = f->is_local;
                        if (!f->is_static)
                                fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->ageing_timer);
@@ -264,7 +310,7 @@ static inline struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
        struct net_bridge_fdb_entry *fdb;
 
        hlist_for_each_entry_rcu(fdb, h, head, hlist) {
-               if (!memcmp(fdb->addr.addr, addr, ETH_ALEN))
+               if (!compare_ether_addr(fdb->addr.addr, addr))
                        return fdb;
        }
        return NULL;
@@ -272,7 +318,7 @@ static inline struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
 
 static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
                                               struct net_bridge_port *source,
-                                              const unsigned char *addr, 
+                                              const unsigned char *addr,
                                               int is_local)
 {
        struct net_bridge_fdb_entry *fdb;
@@ -280,7 +326,6 @@ static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
        fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
        if (fdb) {
                memcpy(fdb->addr.addr, addr, ETH_ALEN);
-               atomic_set(&fdb->use_count, 1);
                hlist_add_head_rcu(&fdb->hlist, head);
 
                fdb->dst = source;
@@ -302,17 +347,17 @@ static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
 
        fdb = fdb_find(head, addr);
        if (fdb) {
-               /* it is okay to have multiple ports with same 
+               /* it is okay to have multiple ports with same
                 * address, just use the first one.
                 */
-               if (fdb->is_local) 
+               if (fdb->is_local)
                        return 0;
 
                printk(KERN_WARNING "%s adding interface with same address "
                       "as a received packet\n",
                       source->dev->name);
                fdb_delete(fdb);
-       }
+       }
 
        if (!fdb_create(head, source, addr, 1))
                return -ENOMEM;
@@ -341,14 +386,18 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
        if (hold_time(br) == 0)
                return;
 
-       rcu_read_lock();
+       /* ignore packets unless we are using this port */
+       if (!(source->state == BR_STATE_LEARNING ||
+             source->state == BR_STATE_FORWARDING))
+               return;
+
        fdb = fdb_find(head, addr);
        if (likely(fdb)) {
                /* attempt to update an entry for a local interface */
                if (unlikely(fdb->is_local)) {
-                       if (net_ratelimit()) 
+                       if (net_ratelimit())
                                printk(KERN_WARNING "%s: received packet with "
-                                      " own address as source address\n",
+                                      "own address as source address\n",
                                       source->dev->name);
                } else {
                        /* fastpath: update of existing entry */
@@ -356,13 +405,12 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
                        fdb->ageing_timer = jiffies;
                }
        } else {
-               spin_lock_bh(&br->hash_lock);
+               spin_lock(&br->hash_lock);
                if (!fdb_find(head, addr))
                        fdb_create(head, source, addr, 0);
                /* else  we lose race and someone else inserts
                 * it first, don't bother updating
                 */
-               spin_unlock_bh(&br->hash_lock);
+               spin_unlock(&br->hash_lock);
        }
-       rcu_read_unlock();
 }