net-sysfs.c

/*
 * net-sysfs.c - network device class and attributes
 *
 * Copyright (c) 2003 Stephen Hemminger <shemminger@osdl.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/capability.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <net/switchdev.h>
#include <linux/if_arp.h>
#include <linux/slab.h>
#include <linux/nsproxy.h>
#include <net/sock.h>
#include <net/net_namespace.h>
#include <linux/rtnetlink.h>
#include <linux/vmalloc.h>
#include <linux/export.h>
#include <linux/jiffies.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/of_net.h>

#include "net-sysfs.h"

#ifdef CONFIG_SYSFS
static const char fmt_hex[] = "%#x\n";
static const char fmt_dec[] = "%d\n";
static const char fmt_ulong[] = "%lu\n";
static const char fmt_u64[] = "%llu\n";

static inline int dev_isalive(const struct net_device *dev)
{
	return dev->reg_state <= NETREG_REGISTERED;
}

/* use same locking rules as GIF* ioctl's */
static ssize_t netdev_show(const struct device *dev,
			   struct device_attribute *attr, char *buf,
			   ssize_t (*format)(const struct net_device *, char *))
{
	struct net_device *ndev = to_net_dev(dev);
	ssize_t ret = -EINVAL;

	read_lock(&dev_base_lock);
	if (dev_isalive(ndev))
		ret = (*format)(ndev, buf);
	read_unlock(&dev_base_lock);

	return ret;
}

/* generate a show function for simple field */
#define NETDEVICE_SHOW(field, format_string)				\
static ssize_t format_##field(const struct net_device *dev, char *buf)	\
{									\
	return sprintf(buf, format_string, dev->field);			\
}									\
static ssize_t field##_show(struct device *dev,				\
			    struct device_attribute *attr, char *buf)	\
{									\
	return netdev_show(dev, attr, buf, format_##field);		\
}									\

#define NETDEVICE_SHOW_RO(field, format_string)				\
NETDEVICE_SHOW(field, format_string);					\
static DEVICE_ATTR_RO(field)

#define NETDEVICE_SHOW_RW(field, format_string)				\
NETDEVICE_SHOW(field, format_string);					\
static DEVICE_ATTR_RW(field)

/* use same locking and permission rules as SIF* ioctl's */
static ssize_t netdev_store(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t len,
			    int (*set)(struct net_device *, unsigned long))
{
	struct net_device *netdev = to_net_dev(dev);
	struct net *net = dev_net(netdev);
	unsigned long new;
	int ret = -EINVAL;

	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
		return -EPERM;

	ret = kstrtoul(buf, 0, &new);
	if (ret)
		goto err;

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

	if (dev_isalive(netdev)) {
		if ((ret = (*set)(netdev, new)) == 0)
			ret = len;
	}
	rtnl_unlock();
 err:
	return ret;
}

NETDEVICE_SHOW_RO(dev_id, fmt_hex);
NETDEVICE_SHOW_RO(dev_port, fmt_dec);
NETDEVICE_SHOW_RO(addr_assign_type, fmt_dec);
NETDEVICE_SHOW_RO(addr_len, fmt_dec);
NETDEVICE_SHOW_RO(ifindex, fmt_dec);
NETDEVICE_SHOW_RO(type, fmt_dec);
NETDEVICE_SHOW_RO(link_mode, fmt_dec);

static ssize_t iflink_show(struct device *dev, struct device_attribute *attr,
			   char *buf)
{
	struct net_device *ndev = to_net_dev(dev);

	return sprintf(buf, fmt_dec, dev_get_iflink(ndev));
}
static DEVICE_ATTR_RO(iflink);

static ssize_t format_name_assign_type(const struct net_device *dev, char *buf)
{
	return sprintf(buf, fmt_dec, dev->name_assign_type);
}

static ssize_t name_assign_type_show(struct device *dev,
				     struct device_attribute *attr,
				     char *buf)
{
	struct net_device *ndev = to_net_dev(dev);
	ssize_t ret = -EINVAL;

	if (ndev->name_assign_type != NET_NAME_UNKNOWN)
		ret = netdev_show(dev, attr, buf, format_name_assign_type);

	return ret;
}
static DEVICE_ATTR_RO(name_assign_type);

/* use same locking rules as GIFHWADDR ioctl's */
static ssize_t address_show(struct device *dev, struct device_attribute *attr,
			    char *buf)
{
	struct net_device *ndev = to_net_dev(dev);
	ssize_t ret = -EINVAL;

	read_lock(&dev_base_lock);
	if (dev_isalive(ndev))
		ret = sysfs_format_mac(buf, ndev->dev_addr, ndev->addr_len);
	read_unlock(&dev_base_lock);
	return ret;
}
static DEVICE_ATTR_RO(address);

static ssize_t broadcast_show(struct device *dev,
			      struct device_attribute *attr, char *buf)
{
	struct net_device *ndev = to_net_dev(dev);
	if (dev_isalive(ndev))
		return sysfs_format_mac(buf, ndev->broadcast, ndev->addr_len);
	return -EINVAL;
}
static DEVICE_ATTR_RO(broadcast);

static int change_carrier(struct net_device *dev, unsigned long new_carrier)
{
	if (!netif_running(dev))
		return -EINVAL;
	return dev_change_carrier(dev, (bool) new_carrier);
}

static ssize_t carrier_store(struct device *dev, struct device_attribute *attr,
			     const char *buf, size_t len)
{
	return netdev_store(dev, attr, buf, len, change_carrier);
}

static ssize_t carrier_show(struct device *dev,
			    struct device_attribute *attr, char *buf)
{
	struct net_device *netdev = to_net_dev(dev);
	if (netif_running(netdev)) {
		return sprintf(buf, fmt_dec, !!netif_carrier_ok(netdev));
	}
	return -EINVAL;
}
static DEVICE_ATTR_RW(carrier);

static ssize_t speed_show(struct device *dev,
			  struct device_attribute *attr, char *buf)
{
	struct net_device *netdev = to_net_dev(dev);
	int ret = -EINVAL;

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