linux/net/core/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 <linux/if_arp.h>
#include <net/sock.h>
#include <linux/rtnetlink.h>
#include <linux/wireless.h>
#include <net/iw_handler.h>

#include "net-sysfs.h"

#ifdef CONFIG_SYSFS
static const char fmt_hex[] = "%#x\n";
static const char fmt_long_hex[] = "%#lx\n";
static const char fmt_dec[] = "%d\n";
static const char fmt_ulong[] = "%lu\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 *net = to_net_dev(dev);
	ssize_t ret = -EINVAL;

	read_lock(&dev_base_lock);
	if (dev_isalive(net))
		ret = (*format)(net, 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 *net, char *buf)	\
{									\
	return sprintf(buf, format_string, net->field);			\
}									\
static ssize_t show_##field(struct device *dev,				\
			    struct device_attribute *attr, char *buf)	\
{									\
	return netdev_show(dev, attr, buf, format_##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 *net = to_net_dev(dev);
	char *endp;
	unsigned long new;
	int ret = -EINVAL;

	if (!capable(CAP_NET_ADMIN))
		return -EPERM;

	new = simple_strtoul(buf, &endp, 0);
	if (endp == buf)
		goto err;

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

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

NETDEVICE_SHOW(dev_id, fmt_hex);
NETDEVICE_SHOW(addr_len, fmt_dec);
NETDEVICE_SHOW(iflink, fmt_dec);
NETDEVICE_SHOW(ifindex, fmt_dec);
NETDEVICE_SHOW(features, fmt_long_hex);
NETDEVICE_SHOW(type, fmt_dec);
NETDEVICE_SHOW(link_mode, fmt_dec);

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

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

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

static ssize_t show_carrier(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 ssize_t show_dormant(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_dormant(netdev));

	return -EINVAL;
}

static const char *const operstates[] = {
	"unknown",
	"notpresent", /* currently unused */
	"down",
	"lowerlayerdown",
	"testing", /* currently unused */
	"dormant",
	"up"
};

static ssize_t show_operstate(struct device *dev,
			      struct device_attribute *attr, char *buf)
{
	const struct net_device *netdev = to_net_dev(dev);
	unsigned char operstate;

	read_lock(&dev_base_lock);
	operstate = netdev->operstate;
	if (!netif_running(netdev))
		operstate = IF_OPER_DOWN;
	read_unlock(&dev_base_lock);

	if (operstate >= ARRAY_SIZE(operstates))
		return -EINVAL; /* should not happen */

	return sprintf(buf, "%s\n", operstates[operstate]);
}

/* read-write attributes */
NETDEVICE_SHOW(mtu, fmt_dec);

static int change_mtu(struct net_device *net, unsigned long new_mtu)
{
	return dev_set_mtu(net, (int) new_mtu);
}

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

NETDEVICE_SHOW(flags, fmt_hex);

static int change_flags(struct net_device *net, unsigned long new_flags)
{
	return dev_change_flags(net, (unsigned) new_flags);
}

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

NETDEVICE_SHOW(tx_queue_len, fmt_ulong);

static int change_tx_queue_len(struct net_device *net, unsigned long new_len)
{
	net->tx_queue_len = new_len;
	return 0;
}

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

static ssize_t store_ifalias(struct device *dev, struct device_attribute *attr,
			     const char *buf, size_t len)
{
	struct net_device *netdev = to_net_dev(dev);
	size_t count = len;
	ssize_t ret;

	if (!capable(CAP_NET_ADMIN))
		return -EPERM;

	/* ignore trailing newline */
	if (len >  0 && buf[len - 1] == '\n')
		--count;

	if (!rtnl_trylock())
		return restart_syscall();
	ret = dev_set_alias(netdev, buf, count);
	rtnl_unlock();

	return ret < 0 ? ret : len;
}

static ssize_t show_ifalias(struct device *dev,
			    struct device_attribute *attr, char *buf)
{
	const struct net_device *netdev = to_net_dev(dev);
	ssize_t ret = 0;

	if (!rtnl_trylock())
		return restart_syscall();
	if (netdev->ifalias)
		ret = sprintf(buf, "%s\n", netdev->ifalias);
	rtnl_unlock();
	return ret;
}

static struct device_attribute net_class_attributes[] = {
	__ATTR(addr_len, S_IRUGO, show_addr_len, NULL),
	__ATTR(dev_id, S_IRUGO, show_dev_id, NULL),
	__ATTR(ifalias, S_IRUGO | S_IWUSR, show_ifalias, store_ifalias),
	__ATTR(iflink, S_IRUGO, show_iflink, NULL),
	__ATTR(ifindex, S_IRUGO, show_ifindex, NULL),
	__ATTR(features, S_IRUGO, show_features, NULL),
	__ATTR(type, S_IRUGO, show_type, NULL),
	__ATTR(link_mode, S_IRUGO, show_link_mode, NULL),
	__ATTR(address, S_IRUGO, show_address, NULL),
	__ATTR(broadcast, S_IRUGO, show_broadcast, NULL),
	__ATTR(carrier, S_IRUGO, show_carrier, NULL),
	__ATTR(dormant, S_IRUGO, show_dormant, NULL),
	__ATTR(operstate, S_IRUGO, show_operstate, NULL),
	__ATTR(mtu, S_IRUGO | S_IWUSR, show_mtu, store_mtu),
	__ATTR(flags, S_IRUGO | S_IWUSR, show_flags, store_flags),
	__ATTR(tx_queue_len, S_IRUGO | S_IWUSR, show_tx_queue_len,
	       store_tx_queue_len),
	{}
};

/* Show a given an attribute in the statistics group */
static ssize_t netstat_show(const struct device *d,
			    struct device_attribute *attr, char *buf,
			    unsigned long offset)
{
	struct net_device *dev = to_net_dev(d);
	ssize_t ret = -EINVAL;

	WARN_ON(offset > sizeof(struct net_device_stats) ||
			offset % sizeof(unsigned long) != 0);

	read_lock(&dev_base_lock);
	if (dev_isalive(dev)) {
		const struct net_device_stats *stats = dev_get_stats(dev);
		ret = sprintf(buf, fmt_ulong,
			      *(unsigned long *)(((u8 *) stats) + offset));
	}
	read_unlock(&dev_base_lock);
	return ret;
}

/* generate a read-only statistics attribute */
#define NETSTAT_ENTRY(name)						\
static ssize_t show_##name(struct device *d,				\
			   struct device_attribute *attr, char *buf) 	\
{									\
	return netstat_show(d, attr, buf,				\
			    offsetof(struct net_device_stats, name));	\
}									\
static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)

NETSTAT_ENTRY(rx_packets);
NETSTAT_ENTRY(tx_packets);
NETSTAT_ENTRY(rx_bytes);
NETSTAT_ENTRY(tx_bytes);
NETSTAT_ENTRY(rx_errors);
NETSTAT_ENTRY(tx_errors);
NETSTAT_ENTRY(rx_dropped);
NETSTAT_ENTRY(tx_dropped);
NETSTAT_ENTRY(multicast);
NETSTAT_ENTRY(collisions);
NETSTAT_ENTRY(rx_length_errors);
NETSTAT_ENTRY(rx_over_errors);
NETSTAT_ENTRY(rx_crc_errors);
NETSTAT_ENTRY(rx_frame_errors);
NETSTAT_ENTRY(rx_fifo_errors);
NETSTAT_ENTRY(rx_missed_errors);
NETSTAT_ENTRY(tx_aborted_errors);
NETSTAT_ENTRY(tx_carrier_errors);
NETSTAT_ENTRY(tx_fifo_errors);
NETSTAT_ENTRY(tx_heartbeat_errors);
NETSTAT_ENTRY(tx_window_errors);
NETSTAT_ENTRY(rx_compressed);
NETSTAT_ENTRY(tx_compressed);

static struct attribute *netstat_attrs[] = {
	&dev_attr_rx_packets.attr,
	&dev_attr_tx_packets.attr,
	&dev_attr_rx_bytes.attr,
	&dev_attr_tx_bytes.attr,
	&dev_attr_rx_errors.attr,
	&dev_attr_tx_errors.attr,
	&dev_attr_rx_dropped.attr,
	&dev_attr_tx_dropped.attr,
	&dev_attr_multicast.attr,
	&dev_attr_collisions.attr,
	&dev_attr_rx_length_errors.attr,
	&dev_attr_rx_over_errors.attr,
	&dev_attr_rx_crc_errors.attr,
	&dev_attr_rx_frame_errors.attr,
	&dev_attr_rx_fifo_errors.attr,
	&dev_attr_rx_missed_errors.attr,
	&dev_attr_tx_aborted_errors.attr,
	&dev_attr_tx_carrier_errors.attr,
	&dev_attr_tx_fifo_errors.attr,
	&dev_attr_tx_heartbeat_errors.attr,
	&dev_attr_tx_window_errors.attr,
	&dev_attr_rx_compressed.attr,
	&dev_attr_tx_compressed.attr,
	NULL
};


static struct attribute_group netstat_group = {
	.name  = "statistics",
	.attrs  = netstat_attrs,
};

#ifdef CONFIG_WIRELESS_EXT_SYSFS
/* helper function that does all the locking etc for wireless stats */
static ssize_t wireless_show(struct device *d, char *buf,
			     ssize_t (*format)(const struct iw_statistics *,
					       char *))
{
	struct net_device *dev = to_net_dev(d);
	const struct iw_statistics *iw = NULL;
	ssize_t ret = -EINVAL;

	read_lock(&dev_base_lock);
	if (dev_isalive(dev)) {
		if (dev->wireless_handlers &&
		    dev->wireless_handlers->get_wireless_stats)
			iw = dev->wireless_handlers->get_wireless_stats(dev);
		if (iw != NULL)
			ret = (*format)(iw, buf);
	}
	read_unlock(&dev_base_lock);

	return ret;
}

/* show function template for wireless fields */
#define WIRELESS_SHOW(name, field, format_string)			\
static ssize_t format_iw_##name(const struct iw_statistics *iw, char *buf) \
{									\
	return sprintf(buf, format_string, iw->field);			\
}									\
static ssize_t show_iw_##name(struct device *d,				\
			      struct device_attribute *attr, char *buf)	\
{									\
	return wireless_show(d, buf, format_iw_##name);			\
}									\
static DEVICE_ATTR(name, S_IRUGO, show_iw_##name, NULL)

WIRELESS_SHOW(status, status, fmt_hex);
WIRELESS_SHOW(link, qual.qual, fmt_dec);
WIRELESS_SHOW(level, qual.level, fmt_dec);
WIRELESS_SHOW(noise, qual.noise, fmt_dec);
WIRELESS_SHOW(nwid, discard.nwid, fmt_dec);
WIRELESS_SHOW(crypt, discard.code, fmt_dec);
WIRELESS_SHOW(fragment, discard.fragment, fmt_dec);
WIRELESS_SHOW(misc, discard.misc, fmt_dec);
WIRELESS_SHOW(retries, discard.retries, fmt_dec);
WIRELESS_SHOW(beacon, miss.beacon, fmt_dec);

static struct attribute *wireless_attrs[] = {
	&dev_attr_status.attr,
	&dev_attr_link.attr,
	&dev_attr_level.attr,
	&dev_attr_noise.attr,
	&dev_attr_nwid.attr,
	&dev_attr_crypt.attr,
	&dev_attr_fragment.attr,
	&dev_attr_retries.attr,
	&dev_attr_misc.attr,
	&dev_attr_beacon.attr,
	NULL
};

static struct attribute_group wireless_group = {
	.name = "wireless",
	.attrs = wireless_attrs,
};
#endif

#endif /* CONFIG_SYSFS */

#ifdef CONFIG_HOTPLUG
static int netdev_uevent(struct device *d, struct kobj_uevent_env *env)
{
	struct net_device *dev = to_net_dev(d);
	int retval;

	if (!net_eq(dev_net(dev), &init_net))
		return 0;

	/* pass interface to uevent. */
	retval = add_uevent_var(env, "INTERFACE=%s", dev->name);
	if (retval)
		goto exit;

	/* pass ifindex to uevent.
	 * ifindex is useful as it won't change (interface name may change)
	 * and is what RtNetlink uses natively. */
	retval = add_uevent_var(env, "IFINDEX=%d", dev->ifindex);

exit:
	return retval;
}
#endif

/*
 *	netdev_release -- destroy and free a dead device.
 *	Called when last reference to device kobject is gone.
 */
static void netdev_release(struct device *d)
{
	struct net_device *dev = to_net_dev(d);

	BUG_ON(dev->reg_state != NETREG_RELEASED);

	kfree(dev->ifalias);
	kfree((char *)dev - dev->padded);
}

static struct class net_class = {
	.name = "net",
	.dev_release = netdev_release,
#ifdef CONFIG_SYSFS
	.dev_attrs = net_class_attributes,
#endif /* CONFIG_SYSFS */
#ifdef CONFIG_HOTPLUG
	.dev_uevent = netdev_uevent,
#endif
};

/* Delete sysfs entries but hold kobject reference until after all
 * netdev references are gone.
 */
void netdev_unregister_kobject(struct net_device * net)
{
	struct device *dev = &(net->dev);

	kobject_get(&dev->kobj);

	if (dev_net(net) != &init_net)
		return;

	device_del(dev);
}

/* Create sysfs entries for network device. */
int netdev_register_kobject(struct net_device *net)
{
	struct device *dev = &(net->dev);
	struct attribute_group **groups = net->sysfs_groups;

	dev->class = &net_class;
	dev->platform_data = net;
	dev->groups = groups;

	dev_set_name(dev, "%s", net->name);

#ifdef CONFIG_SYSFS
	*groups++ = &netstat_group;

#ifdef CONFIG_WIRELESS_EXT_SYSFS
	if (net->wireless_handlers && net->wireless_handlers->get_wireless_stats)
		*groups++ = &wireless_group;
#endif
#endif /* CONFIG_SYSFS */

	if (dev_net(net) != &init_net)
		return 0;

	return device_add(dev);
}

int netdev_class_create_file(struct class_attribute *class_attr)
{
	return class_create_file(&net_class, class_attr);
}

void netdev_class_remove_file(struct class_attribute *class_attr)
{
	class_remove_file(&net_class, class_attr);
}

EXPORT_SYMBOL(netdev_class_create_file);
EXPORT_SYMBOL(netdev_class_remove_file);

void netdev_initialize_kobject(struct net_device *net)
{
	struct device *device = &(net->dev);
	device_initialize(device);
}

int netdev_kobject_init(void)
{
	return class_register(&net_class);
}