net/bridge/br.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	Generic parts
  *	Linux ethernet bridge
  *
  *	Authors:
  *	Lennert Buytenhek		<buytenh@gnu.org>
  */

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/init.h>
 #include <linux/llc.h>
 #include <net/llc.h>
 #include <net/stp.h>
 #include <net/switchdev.h>

 #include "br_private.h"

 /*
  * Handle changes in state of network devices enslaved to a bridge.
  *
  * Note: don't care about up/down if bridge itself is down, because
  *     port state is checked when bridge is brought up.
  */
 static int br_device_event(struct notifier_block *unused, unsigned long event, void *ptr)
 {
 	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
 	struct netdev_notifier_pre_changeaddr_info *prechaddr_info;
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 	struct net_bridge_port *p;
 	struct net_bridge *br;
 	bool notified = false;
 	bool changed_addr;
 	int err;

 	if (netif_is_bridge_master(dev)) {
 		err = br_vlan_bridge_event(dev, event, ptr);
 		if (err)
 			return notifier_from_errno(err);

 		if (event == NETDEV_REGISTER) {
 			/* register of bridge completed, add sysfs entries */
 			err = br_sysfs_addbr(dev);
 			if (err)
 				return notifier_from_errno(err);

 			return NOTIFY_DONE;
 		}
 	}

 	/* not a port of a bridge */
 	p = br_port_get_rtnl(dev);
 	if (!p)
 		return NOTIFY_DONE;

 	br = p->br;

 	switch (event) {
 	case NETDEV_CHANGEMTU:
 		br_mtu_auto_adjust(br);
 		break;

 	case NETDEV_PRE_CHANGEADDR:
 		if (br->dev->addr_assign_type == NET_ADDR_SET)
 			break;
 		prechaddr_info = ptr;
 		err = dev_pre_changeaddr_notify(br->dev,
 						prechaddr_info->dev_addr,
 						extack);
 		if (err)
 			return notifier_from_errno(err);
 		break;

 	case NETDEV_CHANGEADDR:
 		spin_lock_bh(&br->lock);
 		br_fdb_changeaddr(p, dev->dev_addr);
 		changed_addr = br_stp_recalculate_bridge_id(br);
 		spin_unlock_bh(&br->lock);

 		if (changed_addr)
 			call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);

 		break;

 	case NETDEV_CHANGE:
 		br_port_carrier_check(p, &notified);
 		break;

 	case NETDEV_FEAT_CHANGE:
 		netdev_update_features(br->dev);
 		break;

 	case NETDEV_DOWN:
 		spin_lock_bh(&br->lock);
 		if (br->dev->flags & IFF_UP) {
 			br_stp_disable_port(p);
 			notified = true;
 		}
 		spin_unlock_bh(&br->lock);
 		break;

 	case NETDEV_UP:
 		if (netif_running(br->dev) && netif_oper_up(dev)) {
 			spin_lock_bh(&br->lock);
 			br_stp_enable_port(p);
 			notified = true;
 			spin_unlock_bh(&br->lock);
 		}
 		break;

 	case NETDEV_UNREGISTER:
 		br_del_if(br, dev);
 		break;

 	case NETDEV_CHANGENAME:
 		err = br_sysfs_renameif(p);
 		if (err)
 			return notifier_from_errno(err);
 		break;

 	case NETDEV_PRE_TYPE_CHANGE:
 		/* Forbid underlying device to change its type. */
 		return NOTIFY_BAD;

 	case NETDEV_RESEND_IGMP:
 		/* Propagate to master device */
 		call_netdevice_notifiers(event, br->dev);
 		break;
 	}

 	if (event != NETDEV_UNREGISTER)
 		br_vlan_port_event(p, event);

 	/* Events that may cause spanning tree to refresh */
 	if (!notified && (event == NETDEV_CHANGEADDR || event == NETDEV_UP ||
 			  event == NETDEV_CHANGE || event == NETDEV_DOWN))
 		br_ifinfo_notify(RTM_NEWLINK, NULL, p);

 	return NOTIFY_DONE;
 }

 static struct notifier_block br_device_notifier = {
 	.notifier_call = br_device_event
 };

 /* called with RTNL or RCU */
 static int br_switchdev_event(struct notifier_block *unused,
 			      unsigned long event, void *ptr)
 {
 	struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
 	struct net_bridge_port *p;
 	struct net_bridge *br;
 	struct switchdev_notifier_fdb_info *fdb_info;
 	int err = NOTIFY_DONE;

 	p = br_port_get_rtnl_rcu(dev);
 	if (!p)
 		goto out;

 	br = p->br;

 	switch (event) {
 	case SWITCHDEV_FDB_ADD_TO_BRIDGE:
 		fdb_info = ptr;
 		err = br_fdb_external_learn_add(br, p, fdb_info->addr,
 						fdb_info->vid,
 						fdb_info->locked, false);
 		if (err) {
 			err = notifier_from_errno(err);
 			break;
 		}
 		br_fdb_offloaded_set(br, p, fdb_info->addr,
 				     fdb_info->vid, fdb_info->offloaded);
 		break;
 	case SWITCHDEV_FDB_DEL_TO_BRIDGE:
 		fdb_info = ptr;
 		err = br_fdb_external_learn_del(br, p, fdb_info->addr,
 						fdb_info->vid, false);
 		if (err)
 			err = notifier_from_errno(err);
 		break;
 	case SWITCHDEV_FDB_OFFLOADED:
 		fdb_info = ptr;
 		br_fdb_offloaded_set(br, p, fdb_info->addr,
 				     fdb_info->vid, fdb_info->offloaded);
 		break;
 	case SWITCHDEV_FDB_FLUSH_TO_BRIDGE:
 		fdb_info = ptr;
 		/* Don't delete static entries */
 		br_fdb_delete_by_port(br, p, fdb_info->vid, 0);
 		break;
 	}

 out:
 	return err;
 }

 static struct notifier_block br_switchdev_notifier = {
 	.notifier_call = br_switchdev_event,
 };

 /* called under rtnl_mutex */
 static int br_switchdev_blocking_event(struct notifier_block *nb,
 				       unsigned long event, void *ptr)
 {
 	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
 	struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
 	struct switchdev_notifier_brport_info *brport_info;
 	const struct switchdev_brport *b;
 	struct net_bridge_port *p;
 	int err = NOTIFY_DONE;

 	p = br_port_get_rtnl(dev);
 	if (!p)
 		goto out;

 	switch (event) {
 	case SWITCHDEV_BRPORT_OFFLOADED:
 		brport_info = ptr;
 		b = &brport_info->brport;

 		err = br_switchdev_port_offload(p, b->dev, b->ctx,
 						b->atomic_nb, b->blocking_nb,
 						b->tx_fwd_offload, extack);
 		err = notifier_from_errno(err);
 		break;
 	case SWITCHDEV_BRPORT_UNOFFLOADED:
 		brport_info = ptr;
 		b = &brport_info->brport;

 		br_switchdev_port_unoffload(p, b->ctx, b->atomic_nb,
 					    b->blocking_nb);
 		break;
 	}

 out:
 	return err;
 }

 static struct notifier_block br_switchdev_blocking_notifier = {
 	.notifier_call = br_switchdev_blocking_event,
 };

 /* br_boolopt_toggle - change user-controlled boolean option
  *
  * @br: bridge device
  * @opt: id of the option to change
  * @on: new option value
  * @extack: extack for error messages
  *
  * Changes the value of the respective boolean option to @on taking care of
  * any internal option value mapping and configuration.
  */
 int br_boolopt_toggle(struct net_bridge *br, enum br_boolopt_id opt, bool on,
 		      struct netlink_ext_ack *extack)
 {
 	int err = 0;

 	switch (opt) {
 	case BR_BOOLOPT_NO_LL_LEARN:
 		br_opt_toggle(br, BROPT_NO_LL_LEARN, on);
 		break;
 	case BR_BOOLOPT_MCAST_VLAN_SNOOPING:
 		err = br_multicast_toggle_vlan_snooping(br, on, extack);
 		break;
 	case BR_BOOLOPT_MST_ENABLE:
 		err = br_mst_set_enabled(br, on, extack);
 		break;
 	default:
 		/* shouldn't be called with unsupported options */
 		WARN_ON(1);
 		break;
 	}

 	return err;
 }

 int br_boolopt_get(const struct net_bridge *br, enum br_boolopt_id opt)
 {
 	switch (opt) {
 	case BR_BOOLOPT_NO_LL_LEARN:
 		return br_opt_get(br, BROPT_NO_LL_LEARN);
 	case BR_BOOLOPT_MCAST_VLAN_SNOOPING:
 		return br_opt_get(br, BROPT_MCAST_VLAN_SNOOPING_ENABLED);
 	case BR_BOOLOPT_MST_ENABLE:
 		return br_opt_get(br, BROPT_MST_ENABLED);
 	default:
 		/* shouldn't be called with unsupported options */
 		WARN_ON(1);
 		break;
 	}

 	return 0;
 }

 int br_boolopt_multi_toggle(struct net_bridge *br,
 			    struct br_boolopt_multi *bm,
 			    struct netlink_ext_ack *extack)
 {
 	unsigned long bitmap = bm->optmask;
 	int err = 0;
 	int opt_id;

 	for_each_set_bit(opt_id, &bitmap, BR_BOOLOPT_MAX) {
 		bool on = !!(bm->optval & BIT(opt_id));

 		err = br_boolopt_toggle(br, opt_id, on, extack);
 		if (err) {
 			br_debug(br, "boolopt multi-toggle error: option: %d current: %d new: %d error: %d\n",
 				 opt_id, br_boolopt_get(br, opt_id), on, err);
 			break;
 		}
 	}

 	return err;
 }

 void br_boolopt_multi_get(const struct net_bridge *br,
 			  struct br_boolopt_multi *bm)
 {
 	u32 optval = 0;
 	int opt_id;

 	for (opt_id = 0; opt_id < BR_BOOLOPT_MAX; opt_id++)
 		optval |= (br_boolopt_get(br, opt_id) << opt_id);

 	bm->optval = optval;
 	bm->optmask = GENMASK((BR_BOOLOPT_MAX - 1), 0);
 }

 /* private bridge options, controlled by the kernel */
 void br_opt_toggle(struct net_bridge *br, enum net_bridge_opts opt, bool on)
 {
 	bool cur = !!br_opt_get(br, opt);

 	br_debug(br, "toggle option: %d state: %d -> %d\n",
 		 opt, cur, on);

 	if (cur == on)
 		return;

 	if (on)
 		set_bit(opt, &br->options);
 	else
 		clear_bit(opt, &br->options);
 }

 static void __net_exit br_net_exit_batch(struct list_head *net_list)
 {
 	struct net_device *dev;
 	struct net *net;
 	LIST_HEAD(list);

 	rtnl_lock();

 	list_for_each_entry(net, net_list, exit_list)
 		for_each_netdev(net, dev)
 			if (netif_is_bridge_master(dev))
 				br_dev_delete(dev, &list);

 	unregister_netdevice_many(&list);

 	rtnl_unlock();
 }

 static struct pernet_operations br_net_ops = {
 	.exit_batch	= br_net_exit_batch,
 };

 static const struct stp_proto br_stp_proto = {
 	.rcv	= br_stp_rcv,
 };

 static int __init br_init(void)
 {
 	int err;

 	BUILD_BUG_ON(sizeof(struct br_input_skb_cb) > sizeof_field(struct sk_buff, cb));

 	err = stp_proto_register(&br_stp_proto);
 	if (err < 0) {
 		pr_err("bridge: can't register sap for STP\n");
 		return err;
 	}

 	err = br_fdb_init();
 	if (err)
 		goto err_out;

 	err = register_pernet_subsys(&br_net_ops);
 	if (err)
 		goto err_out1;

 	err = br_nf_core_init();
 	if (err)
 		goto err_out2;

 	err = register_netdevice_notifier(&br_device_notifier);
 	if (err)
 		goto err_out3;

 	err = register_switchdev_notifier(&br_switchdev_notifier);
 	if (err)
 		goto err_out4;

 	err = register_switchdev_blocking_notifier(&br_switchdev_blocking_notifier);
 	if (err)
 		goto err_out5;

 	err = br_netlink_init();
 	if (err)
 		goto err_out6;

 	brioctl_set(br_ioctl_stub);

 #if IS_ENABLED(CONFIG_ATM_LANE)
 	br_fdb_test_addr_hook = br_fdb_test_addr;
 #endif

 #if IS_MODULE(CONFIG_BRIDGE_NETFILTER)
 	pr_info("bridge: filtering via arp/ip/ip6tables is no longer available "
 		"by default. Update your scripts to load br_netfilter if you "
 		"need this.\n");
 #endif

 	return 0;

 err_out6:
 	unregister_switchdev_blocking_notifier(&br_switchdev_blocking_notifier);
 err_out5:
 	unregister_switchdev_notifier(&br_switchdev_notifier);
 err_out4:
 	unregister_netdevice_notifier(&br_device_notifier);
 err_out3:
 	br_nf_core_fini();
 err_out2:
 	unregister_pernet_subsys(&br_net_ops);
 err_out1:
 	br_fdb_fini();
 err_out:
 	stp_proto_unregister(&br_stp_proto);
 	return err;
 }

 static void __exit br_deinit(void)
 {
 	stp_proto_unregister(&br_stp_proto);
 	br_netlink_fini();
 	unregister_switchdev_blocking_notifier(&br_switchdev_blocking_notifier);
 	unregister_switchdev_notifier(&br_switchdev_notifier);
 	unregister_netdevice_notifier(&br_device_notifier);
 	brioctl_set(NULL);
 	unregister_pernet_subsys(&br_net_ops);

 	rcu_barrier(); /* Wait for completion of call_rcu()'s */

 	br_nf_core_fini();
 #if IS_ENABLED(CONFIG_ATM_LANE)
 	br_fdb_test_addr_hook = NULL;
 #endif
 	br_fdb_fini();
 }

 module_init(br_init)
 module_exit(br_deinit)
 MODULE_LICENSE("GPL");
 MODULE_VERSION(BR_VERSION);
 MODULE_ALIAS_RTNL_LINK("bridge");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Generic parts
	* Linux ethernet bridge
	*
	* Authors:
	* Lennert Buytenhek <buytenh@gnu.org>
	*/

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/netdevice.h>
	#include <linux/etherdevice.h>
	#include <linux/init.h>
	#include <linux/llc.h>
	#include <net/llc.h>
	#include <net/stp.h>
	#include <net/switchdev.h>

	#include "br_private.h"

	/*
	* Handle changes in state of network devices enslaved to a bridge.
	*
	* Note: don't care about up/down if bridge itself is down, because
	* port state is checked when bridge is brought up.
	*/
	static int br_device_event(struct notifier_block unused, unsigned long event, void ptr)
	{
	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
	struct netdev_notifier_pre_changeaddr_info *prechaddr_info;
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
	struct net_bridge_port *p;
	struct net_bridge *br;
	bool notified = false;
	bool changed_addr;
	int err;

	if (netif_is_bridge_master(dev)) {
	err = br_vlan_bridge_event(dev, event, ptr);
	if (err)
	return notifier_from_errno(err);

	if (event == NETDEV_REGISTER) {
	/* register of bridge completed, add sysfs entries */
	err = br_sysfs_addbr(dev);
	if (err)
	return notifier_from_errno(err);

	return NOTIFY_DONE;
	}
	}

	/* not a port of a bridge */
	p = br_port_get_rtnl(dev);
	if (!p)
	return NOTIFY_DONE;

	br = p->br;

	switch (event) {
	case NETDEV_CHANGEMTU:
	br_mtu_auto_adjust(br);
	break;

	case NETDEV_PRE_CHANGEADDR:
	if (br->dev->addr_assign_type == NET_ADDR_SET)
	break;
	prechaddr_info = ptr;
	err = dev_pre_changeaddr_notify(br->dev,
	prechaddr_info->dev_addr,
	extack);
	if (err)
	return notifier_from_errno(err);
	break;

	case NETDEV_CHANGEADDR:
	spin_lock_bh(&br->lock);
	br_fdb_changeaddr(p, dev->dev_addr);
	changed_addr = br_stp_recalculate_bridge_id(br);
	spin_unlock_bh(&br->lock);

	if (changed_addr)
	call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);

	break;

	case NETDEV_CHANGE:
	br_port_carrier_check(p, &notified);
	break;

	case NETDEV_FEAT_CHANGE:
	netdev_update_features(br->dev);
	break;

	case NETDEV_DOWN:
	spin_lock_bh(&br->lock);
	if (br->dev->flags & IFF_UP) {
	br_stp_disable_port(p);
	notified = true;
	}
	spin_unlock_bh(&br->lock);
	break;

	case NETDEV_UP:
	if (netif_running(br->dev) && netif_oper_up(dev)) {
	spin_lock_bh(&br->lock);
	br_stp_enable_port(p);
	notified = true;
	spin_unlock_bh(&br->lock);
	}
	break;

	case NETDEV_UNREGISTER:
	br_del_if(br, dev);
	break;

	case NETDEV_CHANGENAME:
	err = br_sysfs_renameif(p);
	if (err)
	return notifier_from_errno(err);
	break;

	case NETDEV_PRE_TYPE_CHANGE:
	/* Forbid underlying device to change its type. */
	return NOTIFY_BAD;

	case NETDEV_RESEND_IGMP:
	/* Propagate to master device */
	call_netdevice_notifiers(event, br->dev);
	break;
	}

	if (event != NETDEV_UNREGISTER)
	br_vlan_port_event(p, event);

	/* Events that may cause spanning tree to refresh */
	if (!notified && (event == NETDEV_CHANGEADDR \|\| event == NETDEV_UP \|\|
	event == NETDEV_CHANGE \|\| event == NETDEV_DOWN))
	br_ifinfo_notify(RTM_NEWLINK, NULL, p);

	return NOTIFY_DONE;
	}

	static struct notifier_block br_device_notifier = {
	.notifier_call = br_device_event
	};

	/* called with RTNL or RCU */
	static int br_switchdev_event(struct notifier_block *unused,
	unsigned long event, void *ptr)
	{
	struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
	struct net_bridge_port *p;
	struct net_bridge *br;
	struct switchdev_notifier_fdb_info *fdb_info;
	int err = NOTIFY_DONE;

	p = br_port_get_rtnl_rcu(dev);
	if (!p)
	goto out;

	br = p->br;

	switch (event) {
	case SWITCHDEV_FDB_ADD_TO_BRIDGE:
	fdb_info = ptr;
	err = br_fdb_external_learn_add(br, p, fdb_info->addr,
	fdb_info->vid,
	fdb_info->locked, false);
	if (err) {
	err = notifier_from_errno(err);
	break;
	}
	br_fdb_offloaded_set(br, p, fdb_info->addr,
	fdb_info->vid, fdb_info->offloaded);
	break;
	case SWITCHDEV_FDB_DEL_TO_BRIDGE:
	fdb_info = ptr;
	err = br_fdb_external_learn_del(br, p, fdb_info->addr,
	fdb_info->vid, false);
	if (err)
	err = notifier_from_errno(err);
	break;
	case SWITCHDEV_FDB_OFFLOADED:
	fdb_info = ptr;
	br_fdb_offloaded_set(br, p, fdb_info->addr,
	fdb_info->vid, fdb_info->offloaded);
	break;
	case SWITCHDEV_FDB_FLUSH_TO_BRIDGE:
	fdb_info = ptr;
	/* Don't delete static entries */
	br_fdb_delete_by_port(br, p, fdb_info->vid, 0);
	break;
	}

	out:
	return err;
	}

	static struct notifier_block br_switchdev_notifier = {
	.notifier_call = br_switchdev_event,
	};

	/* called under rtnl_mutex */
	static int br_switchdev_blocking_event(struct notifier_block *nb,
	unsigned long event, void *ptr)
	{
	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
	struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
	struct switchdev_notifier_brport_info *brport_info;
	const struct switchdev_brport *b;
	struct net_bridge_port *p;
	int err = NOTIFY_DONE;

	p = br_port_get_rtnl(dev);
	if (!p)
	goto out;

	switch (event) {
	case SWITCHDEV_BRPORT_OFFLOADED:
	brport_info = ptr;
	b = &brport_info->brport;

	err = br_switchdev_port_offload(p, b->dev, b->ctx,
	b->atomic_nb, b->blocking_nb,
	b->tx_fwd_offload, extack);
	err = notifier_from_errno(err);
	break;
	case SWITCHDEV_BRPORT_UNOFFLOADED:
	brport_info = ptr;
	b = &brport_info->brport;

	br_switchdev_port_unoffload(p, b->ctx, b->atomic_nb,
	b->blocking_nb);
	break;
	}

	out:
	return err;
	}

	static struct notifier_block br_switchdev_blocking_notifier = {
	.notifier_call = br_switchdev_blocking_event,
	};

	/* br_boolopt_toggle - change user-controlled boolean option
	*
	* @br: bridge device
	* @opt: id of the option to change
	* @on: new option value
	* @extack: extack for error messages
	*
	* Changes the value of the respective boolean option to @on taking care of
	* any internal option value mapping and configuration.
	*/
	int br_boolopt_toggle(struct net_bridge *br, enum br_boolopt_id opt, bool on,
	struct netlink_ext_ack *extack)
	{
	int err = 0;

	switch (opt) {
	case BR_BOOLOPT_NO_LL_LEARN:
	br_opt_toggle(br, BROPT_NO_LL_LEARN, on);
	break;
	case BR_BOOLOPT_MCAST_VLAN_SNOOPING:
	err = br_multicast_toggle_vlan_snooping(br, on, extack);
	break;
	case BR_BOOLOPT_MST_ENABLE:
	err = br_mst_set_enabled(br, on, extack);
	break;
	default:
	/* shouldn't be called with unsupported options */
	WARN_ON(1);
	break;
	}

	return err;
	}

	int br_boolopt_get(const struct net_bridge *br, enum br_boolopt_id opt)
	{
	switch (opt) {
	case BR_BOOLOPT_NO_LL_LEARN:
	return br_opt_get(br, BROPT_NO_LL_LEARN);
	case BR_BOOLOPT_MCAST_VLAN_SNOOPING:
	return br_opt_get(br, BROPT_MCAST_VLAN_SNOOPING_ENABLED);
	case BR_BOOLOPT_MST_ENABLE:
	return br_opt_get(br, BROPT_MST_ENABLED);
	default:
	/* shouldn't be called with unsupported options */
	WARN_ON(1);
	break;
	}

	return 0;
	}

	int br_boolopt_multi_toggle(struct net_bridge *br,
	struct br_boolopt_multi *bm,
	struct netlink_ext_ack *extack)
	{
	unsigned long bitmap = bm->optmask;
	int err = 0;
	int opt_id;

	for_each_set_bit(opt_id, &bitmap, BR_BOOLOPT_MAX) {
	bool on = !!(bm->optval & BIT(opt_id));

	err = br_boolopt_toggle(br, opt_id, on, extack);
	if (err) {
	br_debug(br, "boolopt multi-toggle error: option: %d current: %d new: %d error: %d\n",
	opt_id, br_boolopt_get(br, opt_id), on, err);
	break;
	}
	}

	return err;
	}

	void br_boolopt_multi_get(const struct net_bridge *br,
	struct br_boolopt_multi *bm)
	{
	u32 optval = 0;
	int opt_id;

	for (opt_id = 0; opt_id < BR_BOOLOPT_MAX; opt_id++)
	optval \|= (br_boolopt_get(br, opt_id) << opt_id);

	bm->optval = optval;
	bm->optmask = GENMASK((BR_BOOLOPT_MAX - 1), 0);
	}

	/* private bridge options, controlled by the kernel */
	void br_opt_toggle(struct net_bridge *br, enum net_bridge_opts opt, bool on)
	{
	bool cur = !!br_opt_get(br, opt);

	br_debug(br, "toggle option: %d state: %d -> %d\n",
	opt, cur, on);

	if (cur == on)
	return;

	if (on)
	set_bit(opt, &br->options);
	else
	clear_bit(opt, &br->options);
	}

	static void __net_exit br_net_exit_batch(struct list_head *net_list)
	{
	struct net_device *dev;
	struct net *net;
	LIST_HEAD(list);

	rtnl_lock();

	list_for_each_entry(net, net_list, exit_list)
	for_each_netdev(net, dev)
	if (netif_is_bridge_master(dev))
	br_dev_delete(dev, &list);

	unregister_netdevice_many(&list);

	rtnl_unlock();
	}

	static struct pernet_operations br_net_ops = {
	.exit_batch = br_net_exit_batch,
	};

	static const struct stp_proto br_stp_proto = {
	.rcv = br_stp_rcv,
	};

	static int __init br_init(void)
	{
	int err;

	BUILD_BUG_ON(sizeof(struct br_input_skb_cb) > sizeof_field(struct sk_buff, cb));

	err = stp_proto_register(&br_stp_proto);
	if (err < 0) {
	pr_err("bridge: can't register sap for STP\n");
	return err;
	}

	err = br_fdb_init();
	if (err)
	goto err_out;

	err = register_pernet_subsys(&br_net_ops);
	if (err)
	goto err_out1;

	err = br_nf_core_init();
	if (err)
	goto err_out2;

	err = register_netdevice_notifier(&br_device_notifier);
	if (err)
	goto err_out3;

	err = register_switchdev_notifier(&br_switchdev_notifier);
	if (err)
	goto err_out4;

	err = register_switchdev_blocking_notifier(&br_switchdev_blocking_notifier);
	if (err)
	goto err_out5;

	err = br_netlink_init();
	if (err)
	goto err_out6;

	brioctl_set(br_ioctl_stub);

	#if IS_ENABLED(CONFIG_ATM_LANE)
	br_fdb_test_addr_hook = br_fdb_test_addr;
	#endif

	#if IS_MODULE(CONFIG_BRIDGE_NETFILTER)
	pr_info("bridge: filtering via arp/ip/ip6tables is no longer available "
	"by default. Update your scripts to load br_netfilter if you "
	"need this.\n");
	#endif

	return 0;

	err_out6:
	unregister_switchdev_blocking_notifier(&br_switchdev_blocking_notifier);
	err_out5:
	unregister_switchdev_notifier(&br_switchdev_notifier);
	err_out4:
	unregister_netdevice_notifier(&br_device_notifier);
	err_out3:
	br_nf_core_fini();
	err_out2:
	unregister_pernet_subsys(&br_net_ops);
	err_out1:
	br_fdb_fini();
	err_out:
	stp_proto_unregister(&br_stp_proto);
	return err;
	}

	static void __exit br_deinit(void)
	{
	stp_proto_unregister(&br_stp_proto);
	br_netlink_fini();
	unregister_switchdev_blocking_notifier(&br_switchdev_blocking_notifier);
	unregister_switchdev_notifier(&br_switchdev_notifier);
	unregister_netdevice_notifier(&br_device_notifier);
	brioctl_set(NULL);
	unregister_pernet_subsys(&br_net_ops);

	rcu_barrier(); /* Wait for completion of call_rcu()'s */

	br_nf_core_fini();
	#if IS_ENABLED(CONFIG_ATM_LANE)
	br_fdb_test_addr_hook = NULL;
	#endif
	br_fdb_fini();
	}

	module_init(br_init)
	module_exit(br_deinit)
	MODULE_LICENSE("GPL");
	MODULE_VERSION(BR_VERSION);
	MODULE_ALIAS_RTNL_LINK("bridge");