net/bridge/br_sysfs_if.c - linux/torvalds/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	Sysfs attributes of bridge ports
  *	Linux ethernet bridge
  *
  *	Authors:
  *	Stephen Hemminger		<shemminger@osdl.org>
  */

 #include <linux/capability.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
 #include <linux/if_bridge.h>
 #include <linux/rtnetlink.h>
 #include <linux/spinlock.h>
 #include <linux/sched/signal.h>

 #include "br_private.h"

 struct brport_attribute {
 	struct attribute	attr;
 	ssize_t (*show)(struct net_bridge_port *, char *);
 	int (*store)(struct net_bridge_port *, unsigned long);
 	int (*store_raw)(struct net_bridge_port *, char *);
 };

 #define BRPORT_ATTR_RAW(_name, _mode, _show, _store)			\
 const struct brport_attribute brport_attr_##_name = {			\
 	.attr		= {.name = __stringify(_name),			\
 			   .mode = _mode },				\
 	.show		= _show,					\
 	.store_raw	= _store,					\
 };

 #define BRPORT_ATTR(_name, _mode, _show, _store)		\
 const struct brport_attribute brport_attr_##_name = { 	        \
 	.attr = {.name = __stringify(_name), 			\
 		 .mode = _mode },				\
 	.show	= _show,					\
 	.store	= _store,					\
 };

 #define BRPORT_ATTR_FLAG(_name, _mask)				\
 static ssize_t show_##_name(struct net_bridge_port *p, char *buf) \
 {								\
 	return sprintf(buf, "%d\n", !!(p->flags & _mask));	\
 }								\
 static int store_##_name(struct net_bridge_port *p, unsigned long v) \
 {								\
 	return store_flag(p, v, _mask);				\
 }								\
 static BRPORT_ATTR(_name, 0644,					\
 		   show_##_name, store_##_name)

 static int store_flag(struct net_bridge_port *p, unsigned long v,
 		      unsigned long mask)
 {
 	unsigned long flags;

 	flags = p->flags;

 	if (v)
 		flags |= mask;
 	else
 		flags &= ~mask;

 	if (flags != p->flags) {
 		p->flags = flags;
 		br_port_flags_change(p, mask);
 	}
 	return 0;
 }

 static ssize_t show_path_cost(struct net_bridge_port *p, char *buf)
 {
 	return sprintf(buf, "%d\n", p->path_cost);
 }

 static BRPORT_ATTR(path_cost, 0644,
 		   show_path_cost, br_stp_set_path_cost);

 static ssize_t show_priority(struct net_bridge_port *p, char *buf)
 {
 	return sprintf(buf, "%d\n", p->priority);
 }

 static BRPORT_ATTR(priority, 0644,
 			 show_priority, br_stp_set_port_priority);

 static ssize_t show_designated_root(struct net_bridge_port *p, char *buf)
 {
 	return br_show_bridge_id(buf, &p->designated_root);
 }
 static BRPORT_ATTR(designated_root, 0444, show_designated_root, NULL);

 static ssize_t show_designated_bridge(struct net_bridge_port *p, char *buf)
 {
 	return br_show_bridge_id(buf, &p->designated_bridge);
 }
 static BRPORT_ATTR(designated_bridge, 0444, show_designated_bridge, NULL);

 static ssize_t show_designated_port(struct net_bridge_port *p, char *buf)
 {
 	return sprintf(buf, "%d\n", p->designated_port);
 }
 static BRPORT_ATTR(designated_port, 0444, show_designated_port, NULL);

 static ssize_t show_designated_cost(struct net_bridge_port *p, char *buf)
 {
 	return sprintf(buf, "%d\n", p->designated_cost);
 }
 static BRPORT_ATTR(designated_cost, 0444, show_designated_cost, NULL);

 static ssize_t show_port_id(struct net_bridge_port *p, char *buf)
 {
 	return sprintf(buf, "0x%x\n", p->port_id);
 }
 static BRPORT_ATTR(port_id, 0444, show_port_id, NULL);

 static ssize_t show_port_no(struct net_bridge_port *p, char *buf)
 {
 	return sprintf(buf, "0x%x\n", p->port_no);
 }

 static BRPORT_ATTR(port_no, 0444, show_port_no, NULL);

 static ssize_t show_change_ack(struct net_bridge_port *p, char *buf)
 {
 	return sprintf(buf, "%d\n", p->topology_change_ack);
 }
 static BRPORT_ATTR(change_ack, 0444, show_change_ack, NULL);

 static ssize_t show_config_pending(struct net_bridge_port *p, char *buf)
 {
 	return sprintf(buf, "%d\n", p->config_pending);
 }
 static BRPORT_ATTR(config_pending, 0444, show_config_pending, NULL);

 static ssize_t show_port_state(struct net_bridge_port *p, char *buf)
 {
 	return sprintf(buf, "%d\n", p->state);
 }
 static BRPORT_ATTR(state, 0444, show_port_state, NULL);

 static ssize_t show_message_age_timer(struct net_bridge_port *p,
 					    char *buf)
 {
 	return sprintf(buf, "%ld\n", br_timer_value(&p->message_age_timer));
 }
 static BRPORT_ATTR(message_age_timer, 0444, show_message_age_timer, NULL);

 static ssize_t show_forward_delay_timer(struct net_bridge_port *p,
 					    char *buf)
 {
 	return sprintf(buf, "%ld\n", br_timer_value(&p->forward_delay_timer));
 }
 static BRPORT_ATTR(forward_delay_timer, 0444, show_forward_delay_timer, NULL);

 static ssize_t show_hold_timer(struct net_bridge_port *p,
 					    char *buf)
 {
 	return sprintf(buf, "%ld\n", br_timer_value(&p->hold_timer));
 }
 static BRPORT_ATTR(hold_timer, 0444, show_hold_timer, NULL);

 static int store_flush(struct net_bridge_port *p, unsigned long v)
 {
 	br_fdb_delete_by_port(p->br, p, 0, 0); // Don't delete local entry
 	return 0;
 }
 static BRPORT_ATTR(flush, 0200, NULL, store_flush);

 static ssize_t show_group_fwd_mask(struct net_bridge_port *p, char *buf)
 {
 	return sprintf(buf, "%#x\n", p->group_fwd_mask);
 }

 static int store_group_fwd_mask(struct net_bridge_port *p,
 				unsigned long v)
 {
 	if (v & BR_GROUPFWD_MACPAUSE)
 		return -EINVAL;
 	p->group_fwd_mask = v;

 	return 0;
 }
 static BRPORT_ATTR(group_fwd_mask, 0644, show_group_fwd_mask,
 		   store_group_fwd_mask);

 static ssize_t show_backup_port(struct net_bridge_port *p, char *buf)
 {
 	struct net_bridge_port *backup_p;
 	int ret = 0;

 	rcu_read_lock();
 	backup_p = rcu_dereference(p->backup_port);
 	if (backup_p)
 		ret = sprintf(buf, "%s\n", backup_p->dev->name);
 	rcu_read_unlock();

 	return ret;
 }

 static int store_backup_port(struct net_bridge_port *p, char *buf)
 {
 	struct net_device *backup_dev = NULL;
 	char *nl = strchr(buf, '\n');

 	if (nl)
 		*nl = '\0';

 	if (strlen(buf) > 0) {
 		backup_dev = __dev_get_by_name(dev_net(p->dev), buf);
 		if (!backup_dev)
 			return -ENOENT;
 	}

 	return nbp_backup_change(p, backup_dev);
 }
 static BRPORT_ATTR_RAW(backup_port, 0644, show_backup_port, store_backup_port);

 BRPORT_ATTR_FLAG(hairpin_mode, BR_HAIRPIN_MODE);
 BRPORT_ATTR_FLAG(bpdu_guard, BR_BPDU_GUARD);
 BRPORT_ATTR_FLAG(root_block, BR_ROOT_BLOCK);
 BRPORT_ATTR_FLAG(learning, BR_LEARNING);
 BRPORT_ATTR_FLAG(unicast_flood, BR_FLOOD);
 BRPORT_ATTR_FLAG(proxyarp, BR_PROXYARP);
 BRPORT_ATTR_FLAG(proxyarp_wifi, BR_PROXYARP_WIFI);
 BRPORT_ATTR_FLAG(multicast_flood, BR_MCAST_FLOOD);
 BRPORT_ATTR_FLAG(broadcast_flood, BR_BCAST_FLOOD);
 BRPORT_ATTR_FLAG(neigh_suppress, BR_NEIGH_SUPPRESS);
 BRPORT_ATTR_FLAG(isolated, BR_ISOLATED);

 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 static ssize_t show_multicast_router(struct net_bridge_port *p, char *buf)
 {
 	return sprintf(buf, "%d\n", p->multicast_router);
 }

 static int store_multicast_router(struct net_bridge_port *p,
 				      unsigned long v)
 {
 	return br_multicast_set_port_router(p, v);
 }
 static BRPORT_ATTR(multicast_router, 0644, show_multicast_router,
 		   store_multicast_router);

 BRPORT_ATTR_FLAG(multicast_fast_leave, BR_MULTICAST_FAST_LEAVE);
 BRPORT_ATTR_FLAG(multicast_to_unicast, BR_MULTICAST_TO_UNICAST);
 #endif

 static const struct brport_attribute *brport_attrs[] = {
 	&brport_attr_path_cost,
 	&brport_attr_priority,
 	&brport_attr_port_id,
 	&brport_attr_port_no,
 	&brport_attr_designated_root,
 	&brport_attr_designated_bridge,
 	&brport_attr_designated_port,
 	&brport_attr_designated_cost,
 	&brport_attr_state,
 	&brport_attr_change_ack,
 	&brport_attr_config_pending,
 	&brport_attr_message_age_timer,
 	&brport_attr_forward_delay_timer,
 	&brport_attr_hold_timer,
 	&brport_attr_flush,
 	&brport_attr_hairpin_mode,
 	&brport_attr_bpdu_guard,
 	&brport_attr_root_block,
 	&brport_attr_learning,
 	&brport_attr_unicast_flood,
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 	&brport_attr_multicast_router,
 	&brport_attr_multicast_fast_leave,
 	&brport_attr_multicast_to_unicast,
 #endif
 	&brport_attr_proxyarp,
 	&brport_attr_proxyarp_wifi,
 	&brport_attr_multicast_flood,
 	&brport_attr_broadcast_flood,
 	&brport_attr_group_fwd_mask,
 	&brport_attr_neigh_suppress,
 	&brport_attr_isolated,
 	&brport_attr_backup_port,
 	NULL
 };

 #define to_brport_attr(_at) container_of(_at, struct brport_attribute, attr)

 static ssize_t brport_show(struct kobject *kobj,
 			   struct attribute *attr, char *buf)
 {
 	struct brport_attribute *brport_attr = to_brport_attr(attr);
 	struct net_bridge_port *p = kobj_to_brport(kobj);

 	if (!brport_attr->show)
 		return -EINVAL;

 	return brport_attr->show(p, buf);
 }

 static ssize_t brport_store(struct kobject *kobj,
 			    struct attribute *attr,
 			    const char *buf, size_t count)
 {
 	struct brport_attribute *brport_attr = to_brport_attr(attr);
 	struct net_bridge_port *p = kobj_to_brport(kobj);
 	ssize_t ret = -EINVAL;
 	unsigned long val;
 	char *endp;

 	if (!ns_capable(dev_net(p->dev)->user_ns, CAP_NET_ADMIN))
 		return -EPERM;

 	if (!rtnl_trylock())
 		return restart_syscall();

 	if (brport_attr->store_raw) {
 		char *buf_copy;

 		buf_copy = kstrndup(buf, count, GFP_KERNEL);
 		if (!buf_copy) {
 			ret = -ENOMEM;
 			goto out_unlock;
 		}
 		spin_lock_bh(&p->br->lock);
 		ret = brport_attr->store_raw(p, buf_copy);
 		spin_unlock_bh(&p->br->lock);
 		kfree(buf_copy);
 	} else if (brport_attr->store) {
 		val = simple_strtoul(buf, &endp, 0);
 		if (endp == buf)
 			goto out_unlock;
 		spin_lock_bh(&p->br->lock);
 		ret = brport_attr->store(p, val);
 		spin_unlock_bh(&p->br->lock);
 	}

 	if (!ret) {
 		br_ifinfo_notify(RTM_NEWLINK, NULL, p);
 		ret = count;
 	}
 out_unlock:
 	rtnl_unlock();

 	return ret;
 }

 const struct sysfs_ops brport_sysfs_ops = {
 	.show = brport_show,
 	.store = brport_store,
 };

 /*
  * Add sysfs entries to ethernet device added to a bridge.
  * Creates a brport subdirectory with bridge attributes.
  * Puts symlink in bridge's brif subdirectory
  */
 int br_sysfs_addif(struct net_bridge_port *p)
 {
 	struct net_bridge *br = p->br;
 	const struct brport_attribute **a;
 	int err;

 	err = sysfs_create_link(&p->kobj, &br->dev->dev.kobj,
 				SYSFS_BRIDGE_PORT_LINK);
 	if (err)
 		return err;

 	for (a = brport_attrs; *a; ++a) {
 		err = sysfs_create_file(&p->kobj, &((*a)->attr));
 		if (err)
 			return err;
 	}

 	strlcpy(p->sysfs_name, p->dev->name, IFNAMSIZ);
 	return sysfs_create_link(br->ifobj, &p->kobj, p->sysfs_name);
 }

 /* Rename bridge's brif symlink */
 int br_sysfs_renameif(struct net_bridge_port *p)
 {
 	struct net_bridge *br = p->br;
 	int err;

 	/* If a rename fails, the rollback will cause another
 	 * rename call with the existing name.
 	 */
 	if (!strncmp(p->sysfs_name, p->dev->name, IFNAMSIZ))
 		return 0;

 	err = sysfs_rename_link(br->ifobj, &p->kobj,
 				p->sysfs_name, p->dev->name);
 	if (err)
 		netdev_notice(br->dev, "unable to rename link %s to %s",
 			      p->sysfs_name, p->dev->name);
 	else
 		strlcpy(p->sysfs_name, p->dev->name, IFNAMSIZ);

 	return err;
 }
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Sysfs attributes of bridge ports
	* Linux ethernet bridge
	*
	* Authors:
	* Stephen Hemminger <shemminger@osdl.org>
	*/

	#include <linux/capability.h>
	#include <linux/kernel.h>
	#include <linux/netdevice.h>
	#include <linux/if_bridge.h>
	#include <linux/rtnetlink.h>
	#include <linux/spinlock.h>
	#include <linux/sched/signal.h>

	#include "br_private.h"

	struct brport_attribute {
	struct attribute attr;
	ssize_t (show)(struct net_bridge_port , char *);
	int (store)(struct net_bridge_port , unsigned long);
	int (store_raw)(struct net_bridge_port , char *);
	};

	#define BRPORT_ATTR_RAW(_name, _mode, _show, _store) \
	const struct brport_attribute brport_attr_##_name = { \
	.attr = {.name = __stringify(_name), \
	.mode = _mode }, \
	.show = _show, \
	.store_raw = _store, \
	};

	#define BRPORT_ATTR(_name, _mode, _show, _store) \
	const struct brport_attribute brport_attr_##_name = { \
	.attr = {.name = __stringify(_name), \
	.mode = _mode }, \
	.show = _show, \
	.store = _store, \
	};

	#define BRPORT_ATTR_FLAG(_name, _mask) \
	static ssize_t show_##_name(struct net_bridge_port p, char buf) \
	{ \
	return sprintf(buf, "%d\n", !!(p->flags & _mask)); \
	} \
	static int store_##_name(struct net_bridge_port *p, unsigned long v) \
	{ \
	return store_flag(p, v, _mask); \
	} \
	static BRPORT_ATTR(_name, 0644, \
	show_##_name, store_##_name)

	static int store_flag(struct net_bridge_port *p, unsigned long v,
	unsigned long mask)
	{
	unsigned long flags;

	flags = p->flags;

	if (v)
	flags \|= mask;
	else
	flags &= ~mask;

	if (flags != p->flags) {
	p->flags = flags;
	br_port_flags_change(p, mask);
	}
	return 0;
	}

	static ssize_t show_path_cost(struct net_bridge_port p, char buf)
	{
	return sprintf(buf, "%d\n", p->path_cost);
	}

	static BRPORT_ATTR(path_cost, 0644,
	show_path_cost, br_stp_set_path_cost);

	static ssize_t show_priority(struct net_bridge_port p, char buf)
	{
	return sprintf(buf, "%d\n", p->priority);
	}

	static BRPORT_ATTR(priority, 0644,
	show_priority, br_stp_set_port_priority);

	static ssize_t show_designated_root(struct net_bridge_port p, char buf)
	{
	return br_show_bridge_id(buf, &p->designated_root);
	}
	static BRPORT_ATTR(designated_root, 0444, show_designated_root, NULL);

	static ssize_t show_designated_bridge(struct net_bridge_port p, char buf)
	{
	return br_show_bridge_id(buf, &p->designated_bridge);
	}
	static BRPORT_ATTR(designated_bridge, 0444, show_designated_bridge, NULL);

	static ssize_t show_designated_port(struct net_bridge_port p, char buf)
	{
	return sprintf(buf, "%d\n", p->designated_port);
	}
	static BRPORT_ATTR(designated_port, 0444, show_designated_port, NULL);

	static ssize_t show_designated_cost(struct net_bridge_port p, char buf)
	{
	return sprintf(buf, "%d\n", p->designated_cost);
	}
	static BRPORT_ATTR(designated_cost, 0444, show_designated_cost, NULL);

	static ssize_t show_port_id(struct net_bridge_port p, char buf)
	{
	return sprintf(buf, "0x%x\n", p->port_id);
	}
	static BRPORT_ATTR(port_id, 0444, show_port_id, NULL);

	static ssize_t show_port_no(struct net_bridge_port p, char buf)
	{
	return sprintf(buf, "0x%x\n", p->port_no);
	}

	static BRPORT_ATTR(port_no, 0444, show_port_no, NULL);

	static ssize_t show_change_ack(struct net_bridge_port p, char buf)
	{
	return sprintf(buf, "%d\n", p->topology_change_ack);
	}
	static BRPORT_ATTR(change_ack, 0444, show_change_ack, NULL);

	static ssize_t show_config_pending(struct net_bridge_port p, char buf)
	{
	return sprintf(buf, "%d\n", p->config_pending);
	}
	static BRPORT_ATTR(config_pending, 0444, show_config_pending, NULL);

	static ssize_t show_port_state(struct net_bridge_port p, char buf)
	{
	return sprintf(buf, "%d\n", p->state);
	}
	static BRPORT_ATTR(state, 0444, show_port_state, NULL);

	static ssize_t show_message_age_timer(struct net_bridge_port *p,
	char *buf)
	{
	return sprintf(buf, "%ld\n", br_timer_value(&p->message_age_timer));
	}
	static BRPORT_ATTR(message_age_timer, 0444, show_message_age_timer, NULL);

	static ssize_t show_forward_delay_timer(struct net_bridge_port *p,
	char *buf)
	{
	return sprintf(buf, "%ld\n", br_timer_value(&p->forward_delay_timer));
	}
	static BRPORT_ATTR(forward_delay_timer, 0444, show_forward_delay_timer, NULL);

	static ssize_t show_hold_timer(struct net_bridge_port *p,
	char *buf)
	{
	return sprintf(buf, "%ld\n", br_timer_value(&p->hold_timer));
	}
	static BRPORT_ATTR(hold_timer, 0444, show_hold_timer, NULL);

	static int store_flush(struct net_bridge_port *p, unsigned long v)
	{
	br_fdb_delete_by_port(p->br, p, 0, 0); // Don't delete local entry
	return 0;
	}
	static BRPORT_ATTR(flush, 0200, NULL, store_flush);

	static ssize_t show_group_fwd_mask(struct net_bridge_port p, char buf)
	{
	return sprintf(buf, "%#x\n", p->group_fwd_mask);
	}

	static int store_group_fwd_mask(struct net_bridge_port *p,
	unsigned long v)
	{
	if (v & BR_GROUPFWD_MACPAUSE)
	return -EINVAL;
	p->group_fwd_mask = v;

	return 0;
	}
	static BRPORT_ATTR(group_fwd_mask, 0644, show_group_fwd_mask,
	store_group_fwd_mask);

	static ssize_t show_backup_port(struct net_bridge_port p, char buf)
	{
	struct net_bridge_port *backup_p;
	int ret = 0;

	rcu_read_lock();
	backup_p = rcu_dereference(p->backup_port);
	if (backup_p)
	ret = sprintf(buf, "%s\n", backup_p->dev->name);
	rcu_read_unlock();

	return ret;
	}

	static int store_backup_port(struct net_bridge_port p, char buf)
	{
	struct net_device *backup_dev = NULL;
	char *nl = strchr(buf, '\n');

	if (nl)
	*nl = '\0';

	if (strlen(buf) > 0) {
	backup_dev = __dev_get_by_name(dev_net(p->dev), buf);
	if (!backup_dev)
	return -ENOENT;
	}

	return nbp_backup_change(p, backup_dev);
	}
	static BRPORT_ATTR_RAW(backup_port, 0644, show_backup_port, store_backup_port);

	BRPORT_ATTR_FLAG(hairpin_mode, BR_HAIRPIN_MODE);
	BRPORT_ATTR_FLAG(bpdu_guard, BR_BPDU_GUARD);
	BRPORT_ATTR_FLAG(root_block, BR_ROOT_BLOCK);
	BRPORT_ATTR_FLAG(learning, BR_LEARNING);
	BRPORT_ATTR_FLAG(unicast_flood, BR_FLOOD);
	BRPORT_ATTR_FLAG(proxyarp, BR_PROXYARP);
	BRPORT_ATTR_FLAG(proxyarp_wifi, BR_PROXYARP_WIFI);
	BRPORT_ATTR_FLAG(multicast_flood, BR_MCAST_FLOOD);
	BRPORT_ATTR_FLAG(broadcast_flood, BR_BCAST_FLOOD);
	BRPORT_ATTR_FLAG(neigh_suppress, BR_NEIGH_SUPPRESS);
	BRPORT_ATTR_FLAG(isolated, BR_ISOLATED);

	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
	static ssize_t show_multicast_router(struct net_bridge_port p, char buf)
	{
	return sprintf(buf, "%d\n", p->multicast_router);
	}

	static int store_multicast_router(struct net_bridge_port *p,
	unsigned long v)
	{
	return br_multicast_set_port_router(p, v);
	}
	static BRPORT_ATTR(multicast_router, 0644, show_multicast_router,
	store_multicast_router);

	BRPORT_ATTR_FLAG(multicast_fast_leave, BR_MULTICAST_FAST_LEAVE);
	BRPORT_ATTR_FLAG(multicast_to_unicast, BR_MULTICAST_TO_UNICAST);
	#endif

	static const struct brport_attribute *brport_attrs[] = {
	&brport_attr_path_cost,
	&brport_attr_priority,
	&brport_attr_port_id,
	&brport_attr_port_no,
	&brport_attr_designated_root,
	&brport_attr_designated_bridge,
	&brport_attr_designated_port,
	&brport_attr_designated_cost,
	&brport_attr_state,
	&brport_attr_change_ack,
	&brport_attr_config_pending,
	&brport_attr_message_age_timer,
	&brport_attr_forward_delay_timer,
	&brport_attr_hold_timer,
	&brport_attr_flush,
	&brport_attr_hairpin_mode,
	&brport_attr_bpdu_guard,
	&brport_attr_root_block,
	&brport_attr_learning,
	&brport_attr_unicast_flood,
	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
	&brport_attr_multicast_router,
	&brport_attr_multicast_fast_leave,
	&brport_attr_multicast_to_unicast,
	#endif
	&brport_attr_proxyarp,
	&brport_attr_proxyarp_wifi,
	&brport_attr_multicast_flood,
	&brport_attr_broadcast_flood,
	&brport_attr_group_fwd_mask,
	&brport_attr_neigh_suppress,
	&brport_attr_isolated,
	&brport_attr_backup_port,
	NULL
	};

	#define to_brport_attr(_at) container_of(_at, struct brport_attribute, attr)

	static ssize_t brport_show(struct kobject *kobj,
	struct attribute attr, char buf)
	{
	struct brport_attribute *brport_attr = to_brport_attr(attr);
	struct net_bridge_port *p = kobj_to_brport(kobj);

	if (!brport_attr->show)
	return -EINVAL;

	return brport_attr->show(p, buf);
	}

	static ssize_t brport_store(struct kobject *kobj,
	struct attribute *attr,
	const char *buf, size_t count)
	{
	struct brport_attribute *brport_attr = to_brport_attr(attr);
	struct net_bridge_port *p = kobj_to_brport(kobj);
	ssize_t ret = -EINVAL;
	unsigned long val;
	char *endp;

	if (!ns_capable(dev_net(p->dev)->user_ns, CAP_NET_ADMIN))
	return -EPERM;

	if (!rtnl_trylock())
	return restart_syscall();

	if (brport_attr->store_raw) {
	char *buf_copy;

	buf_copy = kstrndup(buf, count, GFP_KERNEL);
	if (!buf_copy) {
	ret = -ENOMEM;
	goto out_unlock;
	}
	spin_lock_bh(&p->br->lock);
	ret = brport_attr->store_raw(p, buf_copy);
	spin_unlock_bh(&p->br->lock);
	kfree(buf_copy);
	} else if (brport_attr->store) {
	val = simple_strtoul(buf, &endp, 0);
	if (endp == buf)
	goto out_unlock;
	spin_lock_bh(&p->br->lock);
	ret = brport_attr->store(p, val);
	spin_unlock_bh(&p->br->lock);
	}

	if (!ret) {
	br_ifinfo_notify(RTM_NEWLINK, NULL, p);
	ret = count;
	}
	out_unlock:
	rtnl_unlock();

	return ret;
	}

	const struct sysfs_ops brport_sysfs_ops = {
	.show = brport_show,
	.store = brport_store,
	};

	/*
	* Add sysfs entries to ethernet device added to a bridge.
	* Creates a brport subdirectory with bridge attributes.
	* Puts symlink in bridge's brif subdirectory
	*/
	int br_sysfs_addif(struct net_bridge_port *p)
	{
	struct net_bridge *br = p->br;
	const struct brport_attribute **a;
	int err;

	err = sysfs_create_link(&p->kobj, &br->dev->dev.kobj,
	SYSFS_BRIDGE_PORT_LINK);
	if (err)
	return err;

	for (a = brport_attrs; *a; ++a) {
	err = sysfs_create_file(&p->kobj, &((*a)->attr));
	if (err)
	return err;
	}

	strlcpy(p->sysfs_name, p->dev->name, IFNAMSIZ);
	return sysfs_create_link(br->ifobj, &p->kobj, p->sysfs_name);
	}

	/* Rename bridge's brif symlink */
	int br_sysfs_renameif(struct net_bridge_port *p)
	{
	struct net_bridge *br = p->br;
	int err;

	/* If a rename fails, the rollback will cause another
	* rename call with the existing name.
	*/
	if (!strncmp(p->sysfs_name, p->dev->name, IFNAMSIZ))
	return 0;

	err = sysfs_rename_link(br->ifobj, &p->kobj,
	p->sysfs_name, p->dev->name);
	if (err)
	netdev_notice(br->dev, "unable to rename link %s to %s",
	p->sysfs_name, p->dev->name);
	else
	strlcpy(p->sysfs_name, p->dev->name, IFNAMSIZ);

	return err;
	}