/*
* Forwarding database
* Linux ethernet bridge
*
* Authors:
* Lennert Buytenhek <buytenh@gnu.org>
*
* 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
* 2 of the License, or (at your option) any later 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 <linux/slab.h>
#include <linux/atomic.h>
#include <asm/unaligned.h>
#include <linux/if_vlan.h>
#include <net/switchdev.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, u16 vid);
static void fdb_notify(struct net_bridge *br,
const struct net_bridge_fdb_entry *, int);
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);
if (!br_fdb_cache)
return -ENOMEM;
get_random_bytes(&fdb_salt, sizeof(fdb_salt));
return 0;
}
void br_fdb_fini(void)
{
kmem_cache_destroy(br_fdb_cache);
}
/* 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)
{
return br->topology_change ? br->forward_delay : br->ageing_time;
}
static inline int has_expired(const struct net_bridge *br,
const struct net_bridge_fdb_entry *fdb)
{
return !fdb->is_static && !fdb->added_by_external_learn &&
time_before_eq(fdb->updated + hold_time(br), jiffies);
}
static inline int br_mac_hash(const unsigned char *mac, __u16 vid)
{
/* use 1 byte of OUI and 3 bytes of NIC */
u32 key = get_unaligned((u32 *)(mac + 2));
return jhash_2words(key, vid, fdb_salt) & (BR_HASH_SIZE - 1);
}
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 struct net_bridge_fdb_entry *fdb_find_rcu(struct hlist_head *head,
const unsigned char *addr,
__u16 vid)
{
struct net_bridge_fdb_entry *f;
WARN_ON_ONCE(!rcu_read_lock_held());
hlist_for_each_entry_rcu(f, head, hlist)
if (ether_addr_equal(f->addr.addr, addr) && f->vlan_id == vid)
break;
return f;
}
/* requires bridge hash_lock */
static struct net_bridge_fdb_entry *br_fdb_find(struct net_bridge *br,
const unsigned char *addr,
__u16 vid)
{
struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
struct net_bridge_fdb_entry *fdb;
lockdep_assert_held_once(&br->hash_lock);
rcu_read_lock();
fdb = fdb_find_rcu(head, addr, vid);
rcu_read_unlock();
return fdb;
}
struct net_bridge_fdb_entry *br_fdb_find_rcu(struct net_bridge *br,
const unsigned char *addr,
__u16 vid)
{
struct