net/bridge/br_if.c - kernel/msm - Gitiles

 /*
  *	Userspace interface
  *	Linux ethernet bridge
  *
  *	Authors:
  *	Lennert Buytenhek		<buytenh@gnu.org>
  *
  *	$Id: br_if.c,v 1.7 2001/12/24 00:59:55 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
  *	2 of the License, or (at your option) any later version.
  */

 #include <linux/kernel.h>
 #include <linux/netdevice.h>
 #include <linux/ethtool.h>
 #include <linux/if_arp.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/rtnetlink.h>
 #include <linux/if_ether.h>
 #include <net/sock.h>

 #include "br_private.h"

 /*
  * Determine initial path cost based on speed.
  * using recommendations from 802.1d standard
  *
  * Need to simulate user ioctl because not all device's that support
  * ethtool, use ethtool_ops.  Also, since driver might sleep need to
  * not be holding any locks.
  */
 static int port_cost(struct net_device *dev)
 {
 	struct ethtool_cmd ecmd = { ETHTOOL_GSET };
 	struct ifreq ifr;
 	mm_segment_t old_fs;
 	int err;

 	strncpy(ifr.ifr_name, dev->name, IFNAMSIZ);
 	ifr.ifr_data = (void __user *) &ecmd;

 	old_fs = get_fs();
 	set_fs(KERNEL_DS);
 	err = dev_ethtool(&ifr);
 	set_fs(old_fs);

 	if (!err) {
 		switch(ecmd.speed) {
 		case SPEED_100:
 			return 19;
 		case SPEED_1000:
 			return 4;
 		case SPEED_10000:
 			return 2;
 		case SPEED_10:
 			return 100;
 		}
 	}

 	/* Old silly heuristics based on name */
 	if (!strncmp(dev->name, "lec", 3))
 		return 7;

 	if (!strncmp(dev->name, "plip", 4))
 		return 2500;

 	return 100;	/* assume old 10Mbps */
 }


 /*
  * Check for port carrier transistions.
  * Called from work queue to allow for calling functions that
  * might sleep (such as speed check), and to debounce.
  */
 static void port_carrier_check(void *arg)
 {
 	struct net_device *dev = arg;
 	struct net_bridge_port *p;
 	struct net_bridge *br;

 	rtnl_lock();
 	p = dev->br_port;
 	if (!p)
 		goto done;
 	br = p->br;

 	if (netif_carrier_ok(dev))
 		p->path_cost = port_cost(dev);

 	if (br->dev->flags & IFF_UP) {
 		spin_lock_bh(&br->lock);
 		if (netif_carrier_ok(dev)) {
 			if (p->state == BR_STATE_DISABLED)
 				br_stp_enable_port(p);
 		} else {
 			if (p->state != BR_STATE_DISABLED)
 				br_stp_disable_port(p);
 		}
 		spin_unlock_bh(&br->lock);
 	}
 done:
 	rtnl_unlock();
 }

 static void release_nbp(struct kobject *kobj)
 {
 	struct net_bridge_port *p
 		= container_of(kobj, struct net_bridge_port, kobj);
 	kfree(p);
 }

 static struct kobj_type brport_ktype = {
 #ifdef CONFIG_SYSFS
 	.sysfs_ops = &brport_sysfs_ops,
 #endif
 	.release = release_nbp,
 };

 static void destroy_nbp(struct net_bridge_port *p)
 {
 	struct net_device *dev = p->dev;

 	p->br = NULL;
 	p->dev = NULL;
 	dev_put(dev);

 	kobject_put(&p->kobj);
 }

 static void destroy_nbp_rcu(struct rcu_head *head)
 {
 	struct net_bridge_port *p =
 			container_of(head, struct net_bridge_port, rcu);
 	destroy_nbp(p);
 }

 /* Delete port(interface) from bridge is done in two steps.
  * via RCU. First step, marks device as down. That deletes
  * all the timers and stops new packets from flowing through.
  *
  * Final cleanup doesn't occur until after all CPU's finished
  * processing packets.
  *
  * Protected from multiple admin operations by RTNL mutex
  */
 static void del_nbp(struct net_bridge_port *p)
 {
 	struct net_bridge *br = p->br;
 	struct net_device *dev = p->dev;

 	sysfs_remove_link(&br->ifobj, dev->name);

 	dev_set_promiscuity(dev, -1);

 	cancel_delayed_work(&p->carrier_check);

 	spin_lock_bh(&br->lock);
 	br_stp_disable_port(p);
 	spin_unlock_bh(&br->lock);

 	br_fdb_delete_by_port(br, p);

 	list_del_rcu(&p->list);

 	rcu_assign_pointer(dev->br_port, NULL);

 	kobject_uevent(&p->kobj, KOBJ_REMOVE);
 	kobject_del(&p->kobj);

 	call_rcu(&p->rcu, destroy_nbp_rcu);
 }

 /* called with RTNL */
 static void del_br(struct net_bridge *br)
 {
 	struct net_bridge_port *p, *n;

 	list_for_each_entry_safe(p, n, &br->port_list, list) {
 		del_nbp(p);
 	}

 	del_timer_sync(&br->gc_timer);

 	br_sysfs_delbr(br->dev);
  	unregister_netdevice(br->dev);
 }

 static struct net_device *new_bridge_dev(const char *name)
 {
 	struct net_bridge *br;
 	struct net_device *dev;

 	dev = alloc_netdev(sizeof(struct net_bridge), name,
 			   br_dev_setup);

 	if (!dev)
 		return NULL;

 	br = netdev_priv(dev);
 	br->dev = dev;

 	spin_lock_init(&br->lock);
 	INIT_LIST_HEAD(&br->port_list);
 	spin_lock_init(&br->hash_lock);

 	br->bridge_id.prio[0] = 0x80;
 	br->bridge_id.prio[1] = 0x00;

 	memcpy(br->group_addr, br_group_address, ETH_ALEN);

 	br->feature_mask = dev->features;
 	br->stp_enabled = 0;
 	br->designated_root = br->bridge_id;
 	br->root_path_cost = 0;
 	br->root_port = 0;
 	br->bridge_max_age = br->max_age = 20 * HZ;
 	br->bridge_hello_time = br->hello_time = 2 * HZ;
 	br->bridge_forward_delay = br->forward_delay = 15 * HZ;
 	br->topology_change = 0;
 	br->topology_change_detected = 0;
 	br->ageing_time = 300 * HZ;
 	INIT_LIST_HEAD(&br->age_list);

 	br_stp_timer_init(br);

 	return dev;
 }

 /* find an available port number */
 static int find_portno(struct net_bridge *br)
 {
 	int index;
 	struct net_bridge_port *p;
 	unsigned long *inuse;

 	inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
 			GFP_KERNEL);
 	if (!inuse)
 		return -ENOMEM;

 	set_bit(0, inuse);	/* zero is reserved */
 	list_for_each_entry(p, &br->port_list, list) {
 		set_bit(p->port_no, inuse);
 	}
 	index = find_first_zero_bit(inuse, BR_MAX_PORTS);
 	kfree(inuse);

 	return (index >= BR_MAX_PORTS) ? -EXFULL : index;
 }

 /* called with RTNL but without bridge lock */
 static struct net_bridge_port *new_nbp(struct net_bridge *br,
 				       struct net_device *dev)
 {
 	int index;
 	struct net_bridge_port *p;

 	index = find_portno(br);
 	if (index < 0)
 		return ERR_PTR(index);

 	p = kzalloc(sizeof(*p), GFP_KERNEL);
 	if (p == NULL)
 		return ERR_PTR(-ENOMEM);

 	p->br = br;
 	dev_hold(dev);
 	p->dev = dev;
 	p->path_cost = port_cost(dev);
  	p->priority = 0x8000 >> BR_PORT_BITS;
 	p->port_no = index;
 	br_init_port(p);
 	p->state = BR_STATE_DISABLED;
 	INIT_WORK(&p->carrier_check, port_carrier_check, dev);
 	br_stp_port_timer_init(p);

 	kobject_init(&p->kobj);
 	kobject_set_name(&p->kobj, SYSFS_BRIDGE_PORT_ATTR);
 	p->kobj.ktype = &brport_ktype;
 	p->kobj.parent = &(dev->class_dev.kobj);
 	p->kobj.kset = NULL;

 	return p;
 }

 int br_add_bridge(const char *name)
 {
 	struct net_device *dev;
 	int ret;

 	dev = new_bridge_dev(name);
 	if (!dev)
 		return -ENOMEM;

 	rtnl_lock();
 	if (strchr(dev->name, '%')) {
 		ret = dev_alloc_name(dev, dev->name);
 		if (ret < 0) {
 			free_netdev(dev);
 			goto out;
 		}
 	}

 	ret = register_netdevice(dev);
 	if (ret)
 		goto out;

 	ret = br_sysfs_addbr(dev);
 	if (ret)
 		unregister_netdevice(dev);
  out:
 	rtnl_unlock();
 	return ret;
 }

 int br_del_bridge(const char *name)
 {
 	struct net_device *dev;
 	int ret = 0;

 	rtnl_lock();
 	dev = __dev_get_by_name(name);
 	if (dev == NULL)
 		ret =  -ENXIO; 	/* Could not find device */

 	else if (!(dev->priv_flags & IFF_EBRIDGE)) {
 		/* Attempt to delete non bridge device! */
 		ret = -EPERM;
 	}

 	else if (dev->flags & IFF_UP) {
 		/* Not shutdown yet. */
 		ret = -EBUSY;
 	}

 	else
 		del_br(netdev_priv(dev));

 	rtnl_unlock();
 	return ret;
 }

 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
 int br_min_mtu(const struct net_bridge *br)
 {
 	const struct net_bridge_port *p;
 	int mtu = 0;

 	ASSERT_RTNL();

 	if (list_empty(&br->port_list))
 		mtu = ETH_DATA_LEN;
 	else {
 		list_for_each_entry(p, &br->port_list, list) {
 			if (!mtu  || p->dev->mtu < mtu)
 				mtu = p->dev->mtu;
 		}
 	}
 	return mtu;
 }

 /*
  * Recomputes features using slave's features
  */
 void br_features_recompute(struct net_bridge *br)
 {
 	struct net_bridge_port *p;
 	unsigned long features, checksum;

 	checksum = br->feature_mask & NETIF_F_ALL_CSUM ? NETIF_F_NO_CSUM : 0;
 	features = br->feature_mask & ~NETIF_F_ALL_CSUM;

 	list_for_each_entry(p, &br->port_list, list) {
 		unsigned long feature = p->dev->features;

 		if (checksum & NETIF_F_NO_CSUM && !(feature & NETIF_F_NO_CSUM))
 			checksum ^= NETIF_F_NO_CSUM | NETIF_F_HW_CSUM;
 		if (checksum & NETIF_F_HW_CSUM && !(feature & NETIF_F_HW_CSUM))
 			checksum ^= NETIF_F_HW_CSUM | NETIF_F_IP_CSUM;
 		if (!(feature & NETIF_F_IP_CSUM))
 			checksum = 0;

 		if (feature & NETIF_F_GSO)
 			feature |= NETIF_F_GSO_SOFTWARE;
 		feature |= NETIF_F_GSO;

 		features &= feature;
 	}

 	if (!(checksum & NETIF_F_ALL_CSUM))
 		features &= ~NETIF_F_SG;
 	if (!(features & NETIF_F_SG))
 		features &= ~NETIF_F_GSO_MASK;

 	br->dev->features = features | checksum | NETIF_F_LLTX |
 			    NETIF_F_GSO_ROBUST;
 }

 /* called with RTNL */
 int br_add_if(struct net_bridge *br, struct net_device *dev)
 {
 	struct net_bridge_port *p;
 	int err = 0;

 	if (dev->flags & IFF_LOOPBACK || dev->type != ARPHRD_ETHER)
 		return -EINVAL;

 	if (dev->hard_start_xmit == br_dev_xmit)
 		return -ELOOP;

 	if (dev->br_port != NULL)
 		return -EBUSY;

 	p = new_nbp(br, dev);
 	if (IS_ERR(p))
 		return PTR_ERR(p);

 	err = kobject_add(&p->kobj);
 	if (err)
 		goto err0;

  	err = br_fdb_insert(br, p, dev->dev_addr);
 	if (err)
 		goto err1;

 	err = br_sysfs_addif(p);
 	if (err)
 		goto err2;

 	rcu_assign_pointer(dev->br_port, p);
 	dev_set_promiscuity(dev, 1);

 	list_add_rcu(&p->list, &br->port_list);

 	spin_lock_bh(&br->lock);
 	br_stp_recalculate_bridge_id(br);
 	br_features_recompute(br);
 	schedule_delayed_work(&p->carrier_check, BR_PORT_DEBOUNCE);
 	spin_unlock_bh(&br->lock);

 	dev_set_mtu(br->dev, br_min_mtu(br));
 	kobject_uevent(&p->kobj, KOBJ_ADD);

 	return 0;
 err2:
 	br_fdb_delete_by_port(br, p);
 err1:
 	kobject_del(&p->kobj);
 err0:
 	kobject_put(&p->kobj);
 	return err;
 }

 /* called with RTNL */
 int br_del_if(struct net_bridge *br, struct net_device *dev)
 {
 	struct net_bridge_port *p = dev->br_port;

 	if (!p || p->br != br)
 		return -EINVAL;

 	del_nbp(p);

 	spin_lock_bh(&br->lock);
 	br_stp_recalculate_bridge_id(br);
 	br_features_recompute(br);
 	spin_unlock_bh(&br->lock);

 	return 0;
 }

 void __exit br_cleanup_bridges(void)
 {
 	struct net_device *dev, *nxt;

 	rtnl_lock();
 	for (dev = dev_base; dev; dev = nxt) {
 		nxt = dev->next;
 		if (dev->priv_flags & IFF_EBRIDGE)
 			del_br(dev->priv);
 	}
 	rtnl_unlock();

 }
	/*
	* Userspace interface
	* Linux ethernet bridge
	*
	* Authors:
	* Lennert Buytenhek <buytenh@gnu.org>
	*
	* $Id: br_if.c,v 1.7 2001/12/24 00:59:55 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
	* 2 of the License, or (at your option) any later version.
	*/

	#include <linux/kernel.h>
	#include <linux/netdevice.h>
	#include <linux/ethtool.h>
	#include <linux/if_arp.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/rtnetlink.h>
	#include <linux/if_ether.h>
	#include <net/sock.h>

	#include "br_private.h"

	/*
	* Determine initial path cost based on speed.
	* using recommendations from 802.1d standard
	*
	* Need to simulate user ioctl because not all device's that support
	* ethtool, use ethtool_ops. Also, since driver might sleep need to
	* not be holding any locks.
	*/
	static int port_cost(struct net_device *dev)
	{
	struct ethtool_cmd ecmd = { ETHTOOL_GSET };
	struct ifreq ifr;
	mm_segment_t old_fs;
	int err;

	strncpy(ifr.ifr_name, dev->name, IFNAMSIZ);
	ifr.ifr_data = (void __user *) &ecmd;

	old_fs = get_fs();
	set_fs(KERNEL_DS);
	err = dev_ethtool(&ifr);
	set_fs(old_fs);

	if (!err) {
	switch(ecmd.speed) {
	case SPEED_100:
	return 19;
	case SPEED_1000:
	return 4;
	case SPEED_10000:
	return 2;
	case SPEED_10:
	return 100;
	}
	}

	/* Old silly heuristics based on name */
	if (!strncmp(dev->name, "lec", 3))
	return 7;

	if (!strncmp(dev->name, "plip", 4))
	return 2500;

	return 100; /* assume old 10Mbps */
	}


	/*
	* Check for port carrier transistions.
	* Called from work queue to allow for calling functions that
	* might sleep (such as speed check), and to debounce.
	*/
	static void port_carrier_check(void *arg)
	{
	struct net_device *dev = arg;
	struct net_bridge_port *p;
	struct net_bridge *br;

	rtnl_lock();
	p = dev->br_port;
	if (!p)
	goto done;
	br = p->br;

	if (netif_carrier_ok(dev))
	p->path_cost = port_cost(dev);

	if (br->dev->flags & IFF_UP) {
	spin_lock_bh(&br->lock);
	if (netif_carrier_ok(dev)) {
	if (p->state == BR_STATE_DISABLED)
	br_stp_enable_port(p);
	} else {
	if (p->state != BR_STATE_DISABLED)
	br_stp_disable_port(p);
	}
	spin_unlock_bh(&br->lock);
	}
	done:
	rtnl_unlock();
	}

	static void release_nbp(struct kobject *kobj)
	{
	struct net_bridge_port *p
	= container_of(kobj, struct net_bridge_port, kobj);
	kfree(p);
	}

	static struct kobj_type brport_ktype = {
	#ifdef CONFIG_SYSFS
	.sysfs_ops = &brport_sysfs_ops,
	#endif
	.release = release_nbp,
	};

	static void destroy_nbp(struct net_bridge_port *p)
	{
	struct net_device *dev = p->dev;

	p->br = NULL;
	p->dev = NULL;
	dev_put(dev);

	kobject_put(&p->kobj);
	}

	static void destroy_nbp_rcu(struct rcu_head *head)
	{
	struct net_bridge_port *p =
	container_of(head, struct net_bridge_port, rcu);
	destroy_nbp(p);
	}

	/* Delete port(interface) from bridge is done in two steps.
	* via RCU. First step, marks device as down. That deletes
	* all the timers and stops new packets from flowing through.
	*
	* Final cleanup doesn't occur until after all CPU's finished
	* processing packets.
	*
	* Protected from multiple admin operations by RTNL mutex
	*/
	static void del_nbp(struct net_bridge_port *p)
	{
	struct net_bridge *br = p->br;
	struct net_device *dev = p->dev;

	sysfs_remove_link(&br->ifobj, dev->name);

	dev_set_promiscuity(dev, -1);

	cancel_delayed_work(&p->carrier_check);

	spin_lock_bh(&br->lock);
	br_stp_disable_port(p);
	spin_unlock_bh(&br->lock);

	br_fdb_delete_by_port(br, p);

	list_del_rcu(&p->list);

	rcu_assign_pointer(dev->br_port, NULL);

	kobject_uevent(&p->kobj, KOBJ_REMOVE);
	kobject_del(&p->kobj);

	call_rcu(&p->rcu, destroy_nbp_rcu);
	}

	/* called with RTNL */
	static void del_br(struct net_bridge *br)
	{
	struct net_bridge_port p, n;

	list_for_each_entry_safe(p, n, &br->port_list, list) {
	del_nbp(p);
	}

	del_timer_sync(&br->gc_timer);

	br_sysfs_delbr(br->dev);
	unregister_netdevice(br->dev);
	}

	static struct net_device new_bridge_dev(const char name)
	{
	struct net_bridge *br;
	struct net_device *dev;

	dev = alloc_netdev(sizeof(struct net_bridge), name,
	br_dev_setup);

	if (!dev)
	return NULL;

	br = netdev_priv(dev);
	br->dev = dev;

	spin_lock_init(&br->lock);
	INIT_LIST_HEAD(&br->port_list);
	spin_lock_init(&br->hash_lock);

	br->bridge_id.prio[0] = 0x80;
	br->bridge_id.prio[1] = 0x00;

	memcpy(br->group_addr, br_group_address, ETH_ALEN);

	br->feature_mask = dev->features;
	br->stp_enabled = 0;
	br->designated_root = br->bridge_id;
	br->root_path_cost = 0;
	br->root_port = 0;
	br->bridge_max_age = br->max_age = 20 * HZ;
	br->bridge_hello_time = br->hello_time = 2 * HZ;
	br->bridge_forward_delay = br->forward_delay = 15 * HZ;
	br->topology_change = 0;
	br->topology_change_detected = 0;
	br->ageing_time = 300 * HZ;
	INIT_LIST_HEAD(&br->age_list);

	br_stp_timer_init(br);

	return dev;
	}

	/* find an available port number */
	static int find_portno(struct net_bridge *br)
	{
	int index;
	struct net_bridge_port *p;
	unsigned long *inuse;

	inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
	GFP_KERNEL);
	if (!inuse)
	return -ENOMEM;

	set_bit(0, inuse); /* zero is reserved */
	list_for_each_entry(p, &br->port_list, list) {
	set_bit(p->port_no, inuse);
	}
	index = find_first_zero_bit(inuse, BR_MAX_PORTS);
	kfree(inuse);

	return (index >= BR_MAX_PORTS) ? -EXFULL : index;
	}

	/* called with RTNL but without bridge lock */
	static struct net_bridge_port new_nbp(struct net_bridge br,
	struct net_device *dev)
	{
	int index;
	struct net_bridge_port *p;

	index = find_portno(br);
	if (index < 0)
	return ERR_PTR(index);

	p = kzalloc(sizeof(*p), GFP_KERNEL);
	if (p == NULL)
	return ERR_PTR(-ENOMEM);

	p->br = br;
	dev_hold(dev);
	p->dev = dev;
	p->path_cost = port_cost(dev);
	p->priority = 0x8000 >> BR_PORT_BITS;
	p->port_no = index;
	br_init_port(p);
	p->state = BR_STATE_DISABLED;
	INIT_WORK(&p->carrier_check, port_carrier_check, dev);
	br_stp_port_timer_init(p);

	kobject_init(&p->kobj);
	kobject_set_name(&p->kobj, SYSFS_BRIDGE_PORT_ATTR);
	p->kobj.ktype = &brport_ktype;
	p->kobj.parent = &(dev->class_dev.kobj);
	p->kobj.kset = NULL;

	return p;
	}

	int br_add_bridge(const char *name)
	{
	struct net_device *dev;
	int ret;

	dev = new_bridge_dev(name);
	if (!dev)
	return -ENOMEM;

	rtnl_lock();
	if (strchr(dev->name, '%')) {
	ret = dev_alloc_name(dev, dev->name);
	if (ret < 0) {
	free_netdev(dev);
	goto out;
	}
	}

	ret = register_netdevice(dev);
	if (ret)
	goto out;

	ret = br_sysfs_addbr(dev);
	if (ret)
	unregister_netdevice(dev);
	out:
	rtnl_unlock();
	return ret;
	}

	int br_del_bridge(const char *name)
	{
	struct net_device *dev;
	int ret = 0;

	rtnl_lock();
	dev = __dev_get_by_name(name);
	if (dev == NULL)
	ret = -ENXIO; /* Could not find device */

	else if (!(dev->priv_flags & IFF_EBRIDGE)) {
	/* Attempt to delete non bridge device! */
	ret = -EPERM;
	}

	else if (dev->flags & IFF_UP) {
	/* Not shutdown yet. */
	ret = -EBUSY;
	}

	else
	del_br(netdev_priv(dev));

	rtnl_unlock();
	return ret;
	}

	/* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
	int br_min_mtu(const struct net_bridge *br)
	{
	const struct net_bridge_port *p;
	int mtu = 0;

	ASSERT_RTNL();

	if (list_empty(&br->port_list))
	mtu = ETH_DATA_LEN;
	else {
	list_for_each_entry(p, &br->port_list, list) {
	if (!mtu \|\| p->dev->mtu < mtu)
	mtu = p->dev->mtu;
	}
	}
	return mtu;
	}

	/*
	* Recomputes features using slave's features
	*/
	void br_features_recompute(struct net_bridge *br)
	{
	struct net_bridge_port *p;
	unsigned long features, checksum;

	checksum = br->feature_mask & NETIF_F_ALL_CSUM ? NETIF_F_NO_CSUM : 0;
	features = br->feature_mask & ~NETIF_F_ALL_CSUM;

	list_for_each_entry(p, &br->port_list, list) {
	unsigned long feature = p->dev->features;

	if (checksum & NETIF_F_NO_CSUM && !(feature & NETIF_F_NO_CSUM))
	checksum ^= NETIF_F_NO_CSUM \| NETIF_F_HW_CSUM;
	if (checksum & NETIF_F_HW_CSUM && !(feature & NETIF_F_HW_CSUM))
	checksum ^= NETIF_F_HW_CSUM \| NETIF_F_IP_CSUM;
	if (!(feature & NETIF_F_IP_CSUM))
	checksum = 0;

	if (feature & NETIF_F_GSO)
	feature \|= NETIF_F_GSO_SOFTWARE;
	feature \|= NETIF_F_GSO;

	features &= feature;
	}

	if (!(checksum & NETIF_F_ALL_CSUM))
	features &= ~NETIF_F_SG;
	if (!(features & NETIF_F_SG))
	features &= ~NETIF_F_GSO_MASK;

	br->dev->features = features \| checksum \| NETIF_F_LLTX \|
	NETIF_F_GSO_ROBUST;
	}

	/* called with RTNL */
	int br_add_if(struct net_bridge br, struct net_device dev)
	{
	struct net_bridge_port *p;
	int err = 0;

	if (dev->flags & IFF_LOOPBACK \|\| dev->type != ARPHRD_ETHER)
	return -EINVAL;

	if (dev->hard_start_xmit == br_dev_xmit)
	return -ELOOP;

	if (dev->br_port != NULL)
	return -EBUSY;

	p = new_nbp(br, dev);
	if (IS_ERR(p))
	return PTR_ERR(p);

	err = kobject_add(&p->kobj);
	if (err)
	goto err0;

	err = br_fdb_insert(br, p, dev->dev_addr);
	if (err)
	goto err1;

	err = br_sysfs_addif(p);
	if (err)
	goto err2;

	rcu_assign_pointer(dev->br_port, p);
	dev_set_promiscuity(dev, 1);

	list_add_rcu(&p->list, &br->port_list);

	spin_lock_bh(&br->lock);
	br_stp_recalculate_bridge_id(br);
	br_features_recompute(br);
	schedule_delayed_work(&p->carrier_check, BR_PORT_DEBOUNCE);
	spin_unlock_bh(&br->lock);

	dev_set_mtu(br->dev, br_min_mtu(br));
	kobject_uevent(&p->kobj, KOBJ_ADD);

	return 0;
	err2:
	br_fdb_delete_by_port(br, p);
	err1:
	kobject_del(&p->kobj);
	err0:
	kobject_put(&p->kobj);
	return err;
	}

	/* called with RTNL */
	int br_del_if(struct net_bridge br, struct net_device dev)
	{
	struct net_bridge_port *p = dev->br_port;

	if (!p \|\| p->br != br)
	return -EINVAL;

	del_nbp(p);

	spin_lock_bh(&br->lock);
	br_stp_recalculate_bridge_id(br);
	br_features_recompute(br);
	spin_unlock_bh(&br->lock);

	return 0;
	}

	void __exit br_cleanup_bridges(void)
	{
	struct net_device dev, nxt;

	rtnl_lock();
	for (dev = dev_base; dev; dev = nxt) {
	nxt = dev->next;
	if (dev->priv_flags & IFF_EBRIDGE)
	del_br(dev->priv);
	}
	rtnl_unlock();

	}