bridge: simpler hash with salt

[powerpc.git] / net / bridge / br_fdb.c

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 8ca448d..dd5a5d5 100644 (file)
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -20,19 +20,24 @@
 #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 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);
 
+static u32 fdb_salt __read_mostly;
+
 void __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);
+       get_random_bytes(&fdb_salt, sizeof(fdb_salt));
 }
 
 void __exit br_fdb_fini(void)
@@ -44,24 +49,26 @@ 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 
+       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 inline void fdb_delete(struct net_bridge_fdb_entry *f)
 {
        hlist_del_rcu(&f->hlist);
        br_fdb_put(f);
@@ -71,7 +78,7 @@ 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 */
@@ -85,7 +92,7 @@ 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 && 
+                                       if (op != p &&
                                            !compare_ether_addr(op->dev->dev_addr,
                                                                f->addr.addr)) {
                                                f->dst = op;
@@ -118,8 +125,8 @@ 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)) 
+                       if (!f->is_static &&
+                           time_before_eq(f->ageing_timer + delay, jiffies))
                                fdb_delete(f);
                }
        }
@@ -138,11 +145,11 @@ void br_fdb_delete_by_port(struct net_bridge *br,
        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)
@@ -155,7 +162,7 @@ void br_fdb_delete_by_port(struct net_bridge *br,
                        if (f->is_local) {
                                struct net_bridge_port *op;
                                list_for_each_entry(op, &br->port_list, list) {
-                                       if (op != p && 
+                                       if (op != p &&
                                            !compare_ether_addr(op->dev->dev_addr,
                                                                f->addr.addr)) {
                                                f->dst = op;
@@ -190,15 +197,15 @@ struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
 }
 
 /* Interface used by ATM hook that keeps a ref count */
-struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br, 
+struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br,
                                        unsigned char *addr)
 {
        struct net_bridge_fdb_entry *fdb;
 
        rcu_read_lock();
        fdb = __br_fdb_get(br, addr);
-       if (fdb) 
-               atomic_inc(&fdb->use_count);
+       if (fdb && !atomic_inc_not_zero(&fdb->use_count))
+               fdb = NULL;
        rcu_read_unlock();
        return fdb;
 }
@@ -218,7 +225,7 @@ void br_fdb_put(struct net_bridge_fdb_entry *ent)
 }
 
 /*
- * 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,
@@ -237,7 +244,7 @@ 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) {
@@ -277,7 +284,7 @@ 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;
@@ -307,17 +314,17 @@ 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;
@@ -350,7 +357,7 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
        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",
                                       source->dev->name);