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linux-next/net/core/net-sysfs.c
Stephen Hemminger 9093bbb2d9 [NET]: Fix race condition about network device name allocation.
Kenji Kaneshige found this race between device removal and
registration.  On unregister it is possible for the old device to
exist, because sysfs file is still open.  A new device with 'eth%d'
will select the same name, but sysfs kobject register will fial.

The following changes the shutdown order slightly. It hold a removes
the sysfs entries earlier (on unregister_netdevice), but holds a
kobject reference.  Then when todo runs the actual last put free
happens.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-05-19 15:39:25 -07:00

499 lines
13 KiB
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>
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;
rtnl_lock();
if (dev_isalive(net)) {
if ((ret = (*set)(net, new)) == 0)
ret = len;
}
rtnl_unlock();
err:
return ret;
}
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 format_addr(char *buf, const unsigned char *addr, int len)
{
int i;
char *cp = buf;
for (i = 0; i < len; i++)
cp += sprintf(cp, "%02x%c", addr[i],
i == (len - 1) ? '\n' : ':');
return cp - buf;
}
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 = format_addr(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 format_addr(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 *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);
}
NETDEVICE_SHOW(weight, fmt_dec);
static int change_weight(struct net_device *net, unsigned long new_weight)
{
net->weight = new_weight;
return 0;
}
static ssize_t store_weight(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len)
{
return netdev_store(dev, attr, buf, len, change_weight);
}
static struct device_attribute net_class_attributes[] = {
__ATTR(addr_len, S_IRUGO, show_addr_len, NULL),
__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),
__ATTR(weight, S_IRUGO | S_IWUSR, show_weight, store_weight),
{}
};
/* 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);
struct net_device_stats *stats;
ssize_t ret = -EINVAL;
if (offset > sizeof(struct net_device_stats) ||
offset % sizeof(unsigned long) != 0)
WARN_ON(1);
read_lock(&dev_base_lock);
if (dev_isalive(dev) && dev->get_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
/* 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
#ifdef CONFIG_HOTPLUG
static int netdev_uevent(struct device *d, char **envp,
int num_envp, char *buf, int size)
{
struct net_device *dev = to_net_dev(d);
int retval, len = 0, i = 0;
/* pass interface to uevent. */
retval = add_uevent_var(envp, num_envp, &i,
buf, size, &len,
"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(envp, num_envp, &i,
buf, size, &len,
"IFINDEX=%d", dev->ifindex);
exit:
envp[i] = NULL;
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((char *)dev - dev->padded);
}
static struct class net_class = {
.name = "net",
.dev_release = netdev_release,
.dev_attrs = net_class_attributes,
#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_sysfs(struct net_device * net)
{
struct device *dev = &(net->dev);
kobject_get(&dev->kobj);
device_del(dev);
}
/* Create sysfs entries for network device. */
int netdev_register_sysfs(struct net_device *net)
{
struct device *dev = &(net->dev);
struct attribute_group **groups = net->sysfs_groups;
device_initialize(dev);
dev->class = &net_class;
dev->platform_data = net;
dev->groups = groups;
BUILD_BUG_ON(BUS_ID_SIZE < IFNAMSIZ);
strlcpy(dev->bus_id, net->name, BUS_ID_SIZE);
if (net->get_stats)
*groups++ = &netstat_group;
#ifdef CONFIG_WIRELESS_EXT
if (net->wireless_handlers && net->wireless_handlers->get_wireless_stats)
*groups++ = &wireless_group;
#endif
return device_add(dev);
}
int netdev_sysfs_init(void)
{
return class_register(&net_class);
}