path: root/net/bridge/br_fdb.c

/*
 *	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 struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
					     const unsigned char *addr,
					     __u16 vid);
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 &&
		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);
}

/* When a static FDB entry is added, the mac address from the entry is
 * added to the bridge private HW address list and all required ports
 * are then updated with the new information.
 * Called under RTNL.
 */
static void fdb_add_hw_addr(struct net_bridge *br, const unsigned char *addr)
{
	int err;
	struct net_bridge_port *p;

	ASSERT_RTNL();

	list_for_each_entry(p, &br->port_list, list) {
		if (!br_promisc_port(p)) {
			err = dev_uc_add(p->dev, addr);
			if (err)
				goto undo;
		}
	}

	return;
undo:
	list_for_each_entry_continue_reverse(p, &br->port_list, list) {
		if (!br_promisc_port(p))
			dev_uc_del(p->dev, addr);
	}
}

/* When a static FDB entry is deleted, the HW address from that entry is
 * also removed from the bridge private HW address list and updates all
 * the ports with needed information.
 * Called under RTNL.
 */
static void fdb_del_hw_addr(struct net_bridge *br, const unsigned char *addr)
{
	struct net_bridge_port *p;

	ASSERT_RTNL();

	list_for_each_entry(p, &br->port_list, list) {
		if (!br_promisc_port(p))
			dev_uc_del(p->dev, addr);
	}
}

static void fdb_del_external_learn(struct net_bridge_fdb_entry *f)
{
	struct switchdev_obj_port_fdb fdb = {
		.obj = {
			.orig_dev = f->dst->dev,
			.id = SWITCHDEV_OBJ_ID_PORT_FDB,
			.flags = SWITCHDEV_F_DEFER,
		},
		.vid = f->vlan_id,
	};

	ether_addr_copy(fdb.addr, f->addr.addr);
	switchdev_port_obj_del(f->dst->dev, &fdb.obj);
}

static void fdb_delete(struct net_bridge *br, struct net_bridge_fdb_entry *f)
{
	if (f