// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright(c) 2004-2005 Intel Corporation. All rights reserved.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/sched/signal.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/in.h>
#include <linux/sysfs.h>
#include <linux/ctype.h>
#include <linux/inet.h>
#include <linux/rtnetlink.h>
#include <linux/etherdevice.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <linux/nsproxy.h>

#include <net/bonding.h>

#define to_bond(cd)	((struct bonding *)(netdev_priv(to_net_dev(cd))))

/* "show" function for the bond_masters attribute.
 * The class parameter is ignored.
 */
static ssize_t bonding_show_bonds(struct class *cls,
				  struct class_attribute *attr,
				  char *buf)
{
	struct bond_net *bn =
		container_of(attr, struct bond_net, class_attr_bonding_masters);
	int res = 0;
	struct bonding *bond;

	rtnl_lock();

	list_for_each_entry(bond, &bn->dev_list, bond_list) {
		if (res > (PAGE_SIZE - IFNAMSIZ)) {
			/* not enough space for another interface name */
			if ((PAGE_SIZE - res) > 10)
				res = PAGE_SIZE - 10;
			res += sprintf(buf + res, "++more++ ");
			break;
		}
		res += sprintf(buf + res, "%s ", bond->dev->name);
	}
	if (res)
		buf[res-1] = '\n'; /* eat the leftover space */

	rtnl_unlock();
	return res;
}

static struct net_device *bond_get_by_name(struct bond_net *bn, const char *ifname)
{
	struct bonding *bond;

	list_for_each_entry(bond, &bn->dev_list, bond_list) {
		if (strncmp(bond->dev->name, ifname, IFNAMSIZ) == 0)
			return bond->dev;
	}
	return NULL;
}

/* "store" function for the bond_masters attribute.  This is what
 * creates and deletes entire bonds.
 *
 * The class parameter is ignored.
 */
static ssize_t bonding_store_bonds(struct class *cls,
				   struct class_attribute *attr,
				   const char *buffer, size_t count)
{
	struct bond_net *bn =
		container_of(attr, struct bond_net, class_attr_bonding_masters);
	char command[IFNAMSIZ + 1] = {0, };
	char *ifname;
	int rv, res = count;

	sscanf(buffer, "%16s", command); /* IFNAMSIZ*/
	ifname = command + 1;
	if ((strlen(command) <= 1) ||
	    !dev_valid_name(ifname))
		goto err_no_cmd;

	if (command[0] == '+') {
		pr_info("%s is being created...\n", ifname);
		rv = bond_create(bn->net, ifname);
		if (rv) {
			if (rv == -EEXIST)
				pr_info("%s already exists\n", ifname);
			else
				pr_info("%s creation failed\n", ifname);
			res = rv;
		}
	} else if (command[0] == '-') {
		struct net_device *bond_dev;

		rtnl_lock();
		bond_dev = bond_get_by_name(bn, ifname);
		if (bond_dev) {
			pr_info("%s is being deleted...\n", ifname);
			unregister_netdevice(bond_dev);
		} else {
			pr_err("unable to delete non-existent %s\n", ifname);
			res = -ENODEV;
		}
		rtnl_unlock();
	} else
		goto err_no_cmd;

	/* Always return either count or an error.  If you return 0, you'll
	 * get called forever, which is bad.
	 */
	return res;

err_no_cmd:
	pr_err("no command found in bonding_masters - use +ifname or -ifname\n");
	return -EPERM;
}

/* class attribute for bond_masters file.  This ends up in /sys/class/net */
static const struct class_attribute class_attr_bonding_masters = {
	.attr = {
		.name = "bonding_masters",
		.mode = 0644,
	},
	.show = bonding_show_bonds,
	.store = bonding_store_bonds,
};

/* Generic "store" method for bonding sysfs option setting */
static ssize_t bonding_sysfs_store_option(struct device *d,
					  struct device_attribute *attr,
					  const char *buffer, size_t count)
{
	struct bonding *bond = to_bond(d);
	const struct bond_option *opt;
	char *buffer_clone;
	int ret;

	opt = bond_opt_get_by_name(attr->attr.name);
	if (WARN_ON(!opt))
		return -ENOENT;
	buffer_clone = kstrndup(buffer, count, GFP_KERNEL);
	if (!buffer_clone)
		return -ENOMEM;
	ret = bond_opt_tryset_rtnl(bond, opt->id, buffer_clone);
	if (!ret)
		ret = count;
	kfree(buffer_clone);

	return ret;
}

/* Show the slaves in the current bond. */
static ssize_t bonding_show_slaves(struct device *d,
				   struct device_attribute *attr, char *buf)
{
	struct bonding *bond = to_bond(d);
	struct list_head *iter;
	struct slave *slave;
	int res = 0;

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

	bond_for_each_slave(bond, slave, iter) {
		if (res > (PAGE_SIZE - IFNAMSIZ)) {
			/* not enough space for another interface name */
			if ((PAGE_SIZE - res) > 10)
				res = PAGE_SIZE - 10;
			res += sprintf(buf + res, "++more++ ");
			break;
		}
		res += sprintf(buf + res, "%s ", slave->dev->name);
	}

	rtnl_unlock();

	if (res)
		buf[res-1] = '\n'; /* eat the leftover space */

	return res;
}
static DEVICE_ATTR(slaves, 0644, bonding_show_slaves,
		   bonding_sysfs_store_option);

/* Show the bonding mode. */
static ssize_t bonding_show_mode(struct device *d,
				 struct device_attribute *attr, char *buf)
{
	struct bonding *bond = to_bond(d);
	const struct bond_opt_value *val;

	val = bond_opt_get_val(BOND_OPT_MODE, BOND_MODE(bond));

	return sprintf(buf, "%s %d\n", val->string, BOND_MODE(bond));
}
static DEVICE_ATTR(mode, 0644, bonding_show_mode, bonding_sysfs_store_option);

/* Show the bonding transmit hash method. */
static ssize_t bonding_show_xmit_hash(struct device *d,
				      struct device_attribute *attr,
				      char *buf)
{
	struct bonding *bond = to_bond(d);
	const struct bond_opt_value *val;

	val = bond_opt_get_val(BOND_OPT_XMIT_HASH, bond->params.xmit_policy);

	return sprintf(buf, "%s %d\n", val->string, bond->params.xmit_policy);
}
static DEVICE_ATTR(xmit_hash_policy, 0644,
		   bonding_show_xmit_hash, bonding_sysfs_store_option);

/* Show arp_validate. */
static ssize_t bonding_show_arp_validate(struct device *d,
					 struct device_attribute *attr,
					 char *buf)
{
	struct bonding *bond = to_bond(d);
	const struct bond_opt_value *val;

	val = bond_opt_get_val(BOND_OPT_ARP_VALIDATE,
			       bond->params.arp_validate);

	return sprintf(buf, "%s %d\n", val->string, bond->params.arp_validate);
}
static DEVICE_ATTR(arp_validate, 0644, bonding_show_arp_validate,
		   bonding_sysfs_store_option);

/* Show arp_all_targets. */
static ssize_t bonding_show_arp_all_targets(struct device *d,
					 struct device_attribute *attr,
					 char *buf)
{
	struct bonding *bond = to_bond(d);
	const struct bond_opt_value *val;

	val = bond_opt_get_val(BOND_OPT_ARP_ALL_TARGETS,
			       bond->params.arp_all_targets);
	return sprintf(buf, "%s %d\n",
		       val->string, bond->params.arp_all_targets);
}
static DEVICE_ATTR(arp_all_targets, 0644,
		   bonding_show_arp_all_targets, bonding_sysfs_store_option);

/* Show fail_over_mac. */
static ssize_t bonding_show_fail_over_mac(struct device *d,
					  struct device_attribute *attr,
					  char *buf)
{
	struct bonding *bond = to_bond(d);
	const struct bond_opt_value *val;

	val = bond_opt_get_val(BOND_OPT_FAIL_OVER_MAC,
			       bond->params.fail_over_mac);

	return sprintf(buf, "%s %d\n", val->string, bond->params.fail_over_mac);
}
static DEVICE_ATTR(fail_over_mac, 0644,
		   bonding_show_fail_over_mac, bonding_sysfs_store_option);

/* Show the arp timer interval. */
static ssize_t bonding_show_arp_interval(struct device *d,
					 struct device_attribute *attr,
					 char *buf)
{
	struct bonding *bond = to_bond(d);

	return sprintf(buf, "%d\n", bond->params.arp_interval);
}
static DEVICE_ATTR(arp_interval, 0644,
		   bonding_show_arp_interval, bonding_sysfs_store_option);

/* Show the arp targets. */
static ssize_t bonding_show_arp_targets(struct device *d,
					struct device_attribute *attr,
					char *buf)
{
	struct bonding *bond = to_bond(d);
	int i, res = 0;

	for (i = 0; i < BOND_MAX_ARP_TARGETS; i++) {
		if (bond->params.arp_targets[i])
			res += sprintf(buf + res, "%pI4 ",
				       &bond->params.arp_targets[i]);
	}
	if (res)
		buf[res-1] = '\n'; /* eat the leftover space */

	return res;
}
static DEVICE_ATTR(arp_ip_target, 0644,
		   bonding_show_arp_targets, bonding_sysfs_store_option);

/* Show the up and down delays. */
static ssize_t bonding_show_downdelay(struct device *d,
				      struct device_attribute *attr,
				      char *buf)
{
	struct bonding *bond = to_bond(d);

	return sprintf(buf, "%d\n", bond->params.downdelay * bond->params.miimon);
}
static DEVICE_ATTR(downdelay, 0644,
		   bonding_show_downdelay, bonding_sysfs_store_option);

static ssize_t bonding_show_updelay(struct device *d,
				    struct device_attribute *attr,
				    char *buf)
{
	struct bonding *bond = to_bond(d);

	return sprintf(buf, "%d\n", bond->params.updelay * bond->params.miimon);

}
static DEVICE_ATTR(updelay, 0644,
		   bonding_show_updelay, bonding_sysfs_store_option);

/* Show the LACP interval. */
static ssize_t bonding_show_lacp(struct device *d,
				 struct device_attribute *attr,
				 char *buf)
{
	struct bonding *bond = to_bond(d);
	const struct bond_opt_value *val;

	val = bond_opt_get_val(BOND_OPT_LACP_RATE, bond->params.lacp_fast);

	return sprintf(buf, "%s %d\n", val->string, bond->params.lacp_fast);
}
static DEVICE_ATTR(lacp_rate, 0644,
		   bonding_show_lacp, bonding_sysfs_store_option);

static ssize_t bonding_show_min_links(struct device *d,
				      struct device_attribute *attr,
				      char *buf)
{
	struct bonding *bond = to_bond(d);

	return sprintf(buf, "%u\n", bond->params.min_links);
}
static DEVICE_ATTR(min_links, 0644,
		   bonding_show_min_links, bonding_sysfs_store_option);

static ssize_t bonding_show_ad_select(struct device *d,
				      struct device_attribute *attr,
				      char *buf)
{
	struct bonding *bond = to_bond(d);
	const struct bond_opt_value *val;

	val = bond_opt_get_val(BOND_OPT_AD_SELECT, bond->params.ad_select);

	return sprintf(buf, "%s %d\n", val->string, bond->params.ad_select);
}
static DEVICE_ATTR(ad_select, 0644,
		   bonding_show_ad_select, bonding_sysfs_store_option);

/* Show the number of peer notifications to send after a failover event. */
static ssize_t bonding_show_num_peer_notif(struct device *d,
					   struct device_attribute *attr,
					   char *buf)
{
	struct bonding *bond = to_bond(d);
	return sprintf(buf, "%d\n", bond->params.num_peer_notif);
}
static DEVICE_ATTR(num_grat_arp, 0644,
		   bonding_show_num_peer_notif, bonding_sysfs_store_option);
static DEVICE_ATTR(num_unsol_na, 0644,
		   bonding_show_num_peer_notif, bonding_sysfs_store_option);

/* Show the MII monitor interval. */
static ssize_t bonding_show_miimon(struct device *d,
				   struct device_attribute *attr,
				   char *buf)
{
	struct bonding *bond = to_bond(d);

	return sprintf(buf, "%d\n", bond->params.miimon);
}
static DEVICE_ATTR(miimon, 0644,
		   bonding_show_miimon, bonding_sysfs_store_option);

/* Show the primary slave. */
static ssize_t bonding_show_primary(struct device *d,
				    struct device_attribute *attr,
				    char *buf)
{
	struct bonding *bond = to_bond(d);
	struct slave *primary;
	int count = 0;

	rcu_read_lock();
	primary = rcu_dereference(bond->primary_slave);
	if (primary)
		count = sprintf(buf, "%s\n", primary->dev->name);
	rcu_read_unlock();

	return count;
}
static DEVICE_ATTR(primary, 0644,
		   bonding_show_primary, bonding_sysfs_store_option);

/* Show the primary_reselect flag. */
static ssize_t bonding_show_primary_reselect(struct device *d,
					     struct device_attribute *attr,
					     char *buf)
{
	struct bonding *bond = to_bond(d);
	const struct bond_opt_value *val;

	val = bond_opt_get_val(BOND_OPT_PRIMARY_RESELECT,
			       bond->params.primary_reselect);

	return sprintf(buf, "%s %d\n",
		       val->string, bond->params.primary_reselect);
}
static DEVICE_ATTR(primary_reselect, 0644,
		   bonding_show_primary_reselect, bonding_sysfs_store_option);

/* Show the use_carrier flag. */
static ssize_t bonding_show_carrier(struct device *d,
				    struct device_attribute *attr,
				    char *buf)
{
	struct bonding *bond = to_bond(d);

	return sprintf(buf, "%d\n", bond->params.use_carrier);
}
static DEVICE_ATTR(use_carrier, 0644,
		   bonding_show_carrier, bonding_sysfs_store_option);


/* Show currently active_slave. */
static ssize_t bonding_show_active_slave(struct device *d,
					 struct device_attribute *attr,
					 char *buf)
{
	struct bonding *bond = to_bond(d);
	struct net_device *slave_dev;
	int count = 0;

	rcu_read_lock();
	slave_dev = bond_option_active_slave_get_rcu(bond);
	if (slave_dev)
		count = sprintf(buf, "%s\n", slave_dev->name);
	rcu_read_unlock();

	return count;
}
static DEVICE_ATTR(active_slave, 0644,
		   bonding_show_active_slave, bonding_sysfs_store_option);

/* Show link status of the bond interface. */
static ssize_t bonding_show_mii_status(struct device *d,
				       struct device_attribute *attr,
				       char *buf)
{
	struct bonding *bond = to_bond(d);
	bool active = netif_carrier_ok(bond->dev);

	return sprintf(buf, "%s\n", active ? "up" : "down");
}
static DEVICE_ATTR(mii_status, 0444, bonding_show_mii_status, NULL);

/* Show current 802.3ad aggregator ID. */
static ssize_t bonding_show_ad_aggregator(struct device *d,
					  struct device_attribute *attr,
					  char *buf)
{
	int count = 0;
	struct bonding *bond = to_bond(d);

	if (BOND_MODE(bond) == BOND_MODE_8023AD) {
		struct ad_info ad_info;
		count = sprintf(buf, "%d\n",
				bond_3ad_get_active_agg_info(bond, &ad_info)
				?  0 : ad_info.aggregator_id);
	}

	return count;
}
static DEVICE_ATTR(ad_aggregator, 0444, bonding_show_ad_aggregator, NULL);


/* Show number of active 802.3ad ports. */
static ssize_t bonding_show_ad_num_ports(struct device *d,
					 struct device_attribute *attr,
					 char *buf)
{
	int count = 0;
	struct bonding *bond = to_bond(d);

	if (BOND_MODE(bond) == BOND_MODE_8023AD) {
		struct ad_info ad_info;
		count = sprintf(buf, "%d\n",
				bond_3ad_get_active_agg_info(bond, &ad_info)
				?  0 : ad_info.ports);
	}

	return count;
}
static DEVICE_ATTR(ad_num_ports, 0444, bonding_show_ad_num_ports, NULL);


/* Show current 802.3ad actor key. */
static ssize_t bonding_show_ad_actor_key(struct device *d,
					 struct device_attribute *attr,
					 char *buf)
{
	int count = 0;
	struct bonding *bond = to_bond(d);

	if (BOND_MODE(bond) == BOND_MODE_8023AD && capable(CAP_NET_ADMIN)) {
		struct ad_info ad_info;
		count = sprintf(buf, "%d\n",
				bond_3ad_get_active_agg_info(bond, &ad_info)
				?  0 : ad_info.actor_key);
	}

	return count;
}
static DEVICE_ATTR(ad_actor_key, 0444, bonding_show_ad_actor_key, NULL);


/* Show current 802.3ad partner key. */
static ssize_t bonding_show_ad_partner_key(struct device *d,
					   struct device_attribute *attr,
					   char *buf)
{
	int count = 0;
	struct bonding *bond = to_bond(d);

	if (BOND_MODE(bond) == BOND_MODE_8023AD && capable(CAP_NET_ADMIN)) {
		struct ad_info ad_info;
		count = sprintf(buf, "%d\n",
				bond_3ad_get_active_agg_info(bond, &ad_info)
				?  0 : ad_info.partner_key);
	}

	return count;
}
static DEVICE_ATTR(ad_partner_key, 0444, bonding_show_ad_partner_key, NULL);


/* Show current 802.3ad partner mac. */
static ssize_t bonding_show_ad_partner_mac(struct device *d,
					   struct device_attribute *attr,
					   char *buf)
{
	int count = 0;
	struct bonding *bond = to_bond(d);

	if (BOND_MODE(bond) == BOND_MODE_8023AD && capable(CAP_NET_ADMIN)) {
		struct ad_info ad_info;
		if (!bond_3ad_get_active_agg_info(bond, &ad_info))
			count = sprintf(buf, "%pM\n", ad_info.partner_system);
	}

	return count;
}
static DEVICE_ATTR(ad_partner_mac, 0444, bonding_show_ad_partner_mac, NULL);

/* Show the queue_ids of the slaves in the current bond. */
static ssize_t bonding_show_queue_id(struct device *d,
				     struct device_attribute *attr,
				     char *buf)
{
	struct bonding *bond = to_bond(d);
	struct list_head *iter;
	struct slave *slave;
	int res = 0;

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

	bond_for_each_slave(bond, slave, iter) {
		if (res > (PAGE_SIZE - IFNAMSIZ - 6)) {
			/* not enough space for another interface_name:queue_id pair */
			if ((PAGE_SIZE - res) > 10)
				res = PAGE_SIZE - 10;
			res += sprintf(buf + res, "++more++ ");
			break;
		}
		res += sprintf(buf + res, "%s:%d ",
			       slave->dev->name, slave->queue_id);
	}
	if (res)
		buf[res-1] = '\n'; /* eat the leftover space */

	rtnl_unlock();

	return res;
}
static DEVICE_ATTR(queue_id, 0644, bonding_show_queue_id,
		   bonding_sysfs_store_option);


/* Show the all_slaves_active flag. */
static ssize_t bonding_show_slaves_active(struct device *d,
					  struct device_attribute *attr,
					  char *buf)
{
	struct bonding *bond = to_bond(d);

	return sprintf(buf, "%d\n", bond->params.all_slaves_active);
}
static DEVICE_ATTR(all_slaves_active, 0644,
		   bonding_show_slaves_active, bonding_sysfs_store_option);

/* Show the number of IGMP membership reports to send on link failure */
static ssize_t bonding_show_resend_igmp(struct device *d,
					struct device_attribute *attr,
					char *buf)
{
	struct bonding *bond = to_bond(d);

	return sprintf(buf, "%d\n", bond->params.resend_igmp);
}
static DEVICE_ATTR(resend_igmp, 0644,
		   bonding_show_resend_igmp, bonding_sysfs_store_option);


static ssize_t bonding_show_lp_interval(struct device *d,
					struct device_attribute *attr,
					char *buf)
{
	struct bonding *bond = to_bond(d);

	return sprintf(buf, "%d\n", bond->params.lp_interval);
}
static DEVICE_ATTR(lp_interval, 0644,
		   bonding_show_lp_interval, bonding_sysfs_store_option);

static ssize_t bonding_show_tlb_dynamic_lb(struct device *d,
					   struct device_attribute *attr,
					   char *buf)
{
	struct bonding *bond = to_bond(d);
	return sprintf(buf, "%d\n", bond->params.tlb_dynamic_lb);
}
static DEVICE_ATTR(tlb_dynamic_lb, 0644,
		   bonding_show_tlb_dynamic_lb, bonding_sysfs_store_option);

static ssize_t bonding_show_packets_per_slave(struct device *d,
					      struct device_attribute *attr,
					      char *buf)
{
	struct bonding *bond = to_bond(d);
	unsigned int packets_per_slave = bond->params.packets_per_slave;

	return sprintf(buf, "%u\n", packets_per_slave);
}
static DEVICE_ATTR(packets_per_slave, 0644,
		   bonding_show_packets_per_slave, bonding_sysfs_store_option);

static ssize_t bonding_show_ad_actor_sys_prio(struct device *d,
					      struct device_attribute *attr,
					      char *buf)
{
	struct bonding *bond = to_bond(d);

	if (BOND_MODE(bond) == BOND_MODE_8023AD && capable(CAP_NET_ADMIN))
		return sprintf(buf, "%hu\n", bond->params.ad_actor_sys_prio);

	return 0;
}
static DEVICE_ATTR(ad_actor_sys_prio, 0644,
		   bonding_show_ad_actor_sys_prio, bonding_sysfs_store_option);

static ssize_t bonding_show_ad_actor_system(struct device *d,
					    struct device_attribute *attr,
					    char *buf)
{
	struct bonding *bond = to_bond(d);

	if (BOND_MODE(bond) == BOND_MODE_8023AD && capable(CAP_NET_ADMIN))
		return sprintf(buf, "%pM\n", bond->params.ad_actor_system);

	return 0;
}

static DEVICE_ATTR(ad_actor_system, 0644,
		   bonding_show_ad_actor_system, bonding_sysfs_store_option);

static ssize_t bonding_show_ad_user_port_key(struct device *d,
					     struct device_attribute *attr,
					     char *buf)
{
	struct bonding *bond = to_bond(d);

	if (BOND_MODE(bond) == BOND_MODE_8023AD && capable(CAP_NET_ADMIN))
		return sprintf(buf, "%hu\n", bond->params.ad_user_port_key);

	return 0;
}
static DEVICE_ATTR(ad_user_port_key, 0644,
		   bonding_show_ad_user_port_key, bonding_sysfs_store_option);

static struct attribute *per_bond_attrs[] = {
	&dev_attr_slaves.attr,
	&dev_attr_mode.attr,
	&dev_attr_fail_over_mac.attr,
	&dev_attr_arp_validate.attr,
	&dev_attr_arp_all_targets.attr,
	&dev_attr_arp_interval.attr,
	&dev_attr_arp_ip_target.attr,
	&dev_attr_downdelay.attr,
	&dev_attr_updelay.attr,
	&dev_attr_lacp_rate.attr,
	&dev_attr_ad_select.attr,
	&dev_attr_xmit_hash_policy.attr,
	&dev_attr_num_grat_arp.attr,
	&dev_attr_num_unsol_na.attr,
	&dev_attr_miimon.attr,
	&dev_attr_primary.attr,
	&dev_attr_primary_reselect.attr,
	&dev_attr_use_carrier.attr,
	&dev_attr_active_slave.attr,
	&dev_attr_mii_status.attr,
	&dev_attr_ad_aggregator.attr,
	&dev_attr_ad_num_ports.attr,
	&dev_attr_ad_actor_key.attr,
	&dev_attr_ad_partner_key.attr,
	&dev_attr_ad_partner_mac.attr,
	&dev_attr_queue_id.attr,
	&dev_attr_all_slaves_active.attr,
	&dev_attr_resend_igmp.attr,
	&dev_attr_min_links.attr,
	&dev_attr_lp_interval.attr,
	&dev_attr_packets_per_slave.attr,
	&dev_attr_tlb_dynamic_lb.attr,
	&dev_attr_ad_actor_sys_prio.attr,
	&dev_attr_ad_actor_system.attr,
	&dev_attr_ad_user_port_key.attr,
	NULL,
};

static const struct attribute_group bonding_group = {
	.name = "bonding",
	.attrs = per_bond_attrs,
};

/* Initialize sysfs.  This sets up the bonding_masters file in
 * /sys/class/net.
 */
int bond_create_sysfs(struct bond_net *bn)
{
	int ret;

	bn->class_attr_bonding_masters = class_attr_bonding_masters;
	sysfs_attr_init(&bn->class_attr_bonding_masters.attr);

	ret = netdev_class_create_file_ns(&bn->class_attr_bonding_masters,
					  bn->net);
	/* Permit multiple loads of the module by ignoring failures to
	 * create the bonding_masters sysfs file.  Bonding devices
	 * created by second or subsequent loads of the module will
	 * not be listed in, or controllable by, bonding_masters, but
	 * will have the usual "bonding" sysfs directory.
	 *
	 * This is done to preserve backwards compatibility for
	 * initscripts/sysconfig, which load bonding multiple times to
	 * configure multiple bonding devices.
	 */
	if (ret == -EEXIST) {
		/* Is someone being kinky and naming a device bonding_master? */
		if (__dev_get_by_name(bn->net,
				      class_attr_bonding_masters.attr.name))
			pr_err("network device named %s already exists in sysfs\n",
			       class_attr_bonding_masters.attr.name);
		ret = 0;
	}

	return ret;

}

/* Remove /sys/class/net/bonding_masters. */
void bond_destroy_sysfs(struct bond_net *bn)
{
	netdev_class_remove_file_ns(&bn->class_attr_bonding_masters, bn->net);
}

/* Initialize sysfs for each bond.  This sets up and registers
 * the 'bondctl' directory for each individual bond under /sys/class/net.
 */
void bond_prepare_sysfs_group(struct bonding *bond)
{
	bond->dev->sysfs_groups[0] = &bonding_group;
}