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linux/drivers/leds/trigger/ledtrig-netdev.c
Rasmus Villemoes 9093464330 leds: trigger: netdev: use memcpy in device_name_store 
If userspace doesn't end the input with a newline (which can easily
happen if the write happens from a C program that does write(fd,
iface, strlen(iface))), we may end up including garbage from a
previous, longer value in the device_name. For example

# cat device_name

# printf 'eth12' > device_name
# cat device_name
eth12
# printf 'eth3' > device_name
# cat device_name
eth32

I highly doubt anybody is relying on this behaviour, so switch to
simply copying the bytes (we've already checked that size is <
IFNAMSIZ) and unconditionally zero-terminate it; of course, we also
still have to strip a trailing newline.

This is also preparation for future patches.

Fixes: 06f502f57d ("leds: trigger: Introduce a NETDEV trigger")
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
2019-03-30 19:09:32 +01:00

459 lines
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// SPDX-License-Identifier: GPL-2.0
// Copyright 2017 Ben Whitten <ben.whitten@gmail.com>
// Copyright 2007 Oliver Jowett <oliver@opencloud.com>
//
// LED Kernel Netdev Trigger
//
// Toggles the LED to reflect the link and traffic state of a named net device
//
// Derived from ledtrig-timer.c which is:
// Copyright 2005-2006 Openedhand Ltd.
// Author: Richard Purdie <rpurdie@openedhand.com>
#include <linux/atomic.h>
#include <linux/ctype.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include "../leds.h"
/*
* Configurable sysfs attributes:
*
* device_name - network device name to monitor
* interval - duration of LED blink, in milliseconds
* link - LED's normal state reflects whether the link is up
* (has carrier) or not
* tx - LED blinks on transmitted data
* rx - LED blinks on receive data
*
*/
struct led_netdev_data {
spinlock_t lock;
struct delayed_work work;
struct notifier_block notifier;
struct led_classdev *led_cdev;
struct net_device *net_dev;
char device_name[IFNAMSIZ];
atomic_t interval;
unsigned int last_activity;
unsigned long mode;
#define NETDEV_LED_LINK 0
#define NETDEV_LED_TX 1
#define NETDEV_LED_RX 2
#define NETDEV_LED_MODE_LINKUP 3
};
enum netdev_led_attr {
NETDEV_ATTR_LINK,
NETDEV_ATTR_TX,
NETDEV_ATTR_RX
};
static void set_baseline_state(struct led_netdev_data *trigger_data)
{
int current_brightness;
struct led_classdev *led_cdev = trigger_data->led_cdev;
current_brightness = led_cdev->brightness;
if (current_brightness)
led_cdev->blink_brightness = current_brightness;
if (!led_cdev->blink_brightness)
led_cdev->blink_brightness = led_cdev->max_brightness;
if (!test_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode))
led_set_brightness(led_cdev, LED_OFF);
else {
if (test_bit(NETDEV_LED_LINK, &trigger_data->mode))
led_set_brightness(led_cdev,
led_cdev->blink_brightness);
else
led_set_brightness(led_cdev, LED_OFF);
/* If we are looking for RX/TX start periodically
* checking stats
*/
if (test_bit(NETDEV_LED_TX, &trigger_data->mode) ||
test_bit(NETDEV_LED_RX, &trigger_data->mode))
schedule_delayed_work(&trigger_data->work, 0);
}
}
static ssize_t device_name_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
ssize_t len;
spin_lock_bh(&trigger_data->lock);
len = sprintf(buf, "%s\n", trigger_data->device_name);
spin_unlock_bh(&trigger_data->lock);
return len;
}
static ssize_t device_name_store(struct device *dev,
struct device_attribute *attr, const char *buf,
size_t size)
{
struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
if (size >= IFNAMSIZ)
return -EINVAL;
cancel_delayed_work_sync(&trigger_data->work);
spin_lock_bh(&trigger_data->lock);
if (trigger_data->net_dev) {
dev_put(trigger_data->net_dev);
trigger_data->net_dev = NULL;
}
memcpy(trigger_data->device_name, buf, size);
trigger_data->device_name[size] = 0;
if (size > 0 && trigger_data->device_name[size - 1] == '\n')
trigger_data->device_name[size - 1] = 0;
if (trigger_data->device_name[0] != 0)
trigger_data->net_dev =
dev_get_by_name(&init_net, trigger_data->device_name);
clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
if (trigger_data->net_dev != NULL)
if (netif_carrier_ok(trigger_data->net_dev))
set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
trigger_data->last_activity = 0;
set_baseline_state(trigger_data);
spin_unlock_bh(&trigger_data->lock);
return size;
}
static DEVICE_ATTR_RW(device_name);
static ssize_t netdev_led_attr_show(struct device *dev, char *buf,
enum netdev_led_attr attr)
{
struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
int bit;
switch (attr) {
case NETDEV_ATTR_LINK:
bit = NETDEV_LED_LINK;
break;
case NETDEV_ATTR_TX:
bit = NETDEV_LED_TX;
break;
case NETDEV_ATTR_RX:
bit = NETDEV_LED_RX;
break;
default:
return -EINVAL;
}
return sprintf(buf, "%u\n", test_bit(bit, &trigger_data->mode));
}
static ssize_t netdev_led_attr_store(struct device *dev, const char *buf,
size_t size, enum netdev_led_attr attr)
{
struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
unsigned long state;
int ret;
int bit;
ret = kstrtoul(buf, 0, &state);
if (ret)
return ret;
switch (attr) {
case NETDEV_ATTR_LINK:
bit = NETDEV_LED_LINK;
break;
case NETDEV_ATTR_TX:
bit = NETDEV_LED_TX;
break;
case NETDEV_ATTR_RX:
bit = NETDEV_LED_RX;
break;
default:
return -EINVAL;
}
cancel_delayed_work_sync(&trigger_data->work);
if (state)
set_bit(bit, &trigger_data->mode);
else
clear_bit(bit, &trigger_data->mode);
set_baseline_state(trigger_data);
return size;
}
static ssize_t link_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return netdev_led_attr_show(dev, buf, NETDEV_ATTR_LINK);
}
static ssize_t link_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t size)
{
return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_LINK);
}
static DEVICE_ATTR_RW(link);
static ssize_t tx_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return netdev_led_attr_show(dev, buf, NETDEV_ATTR_TX);
}
static ssize_t tx_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t size)
{
return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_TX);
}
static DEVICE_ATTR_RW(tx);
static ssize_t rx_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return netdev_led_attr_show(dev, buf, NETDEV_ATTR_RX);
}
static ssize_t rx_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t size)
{
return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_RX);
}
static DEVICE_ATTR_RW(rx);
static ssize_t interval_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
return sprintf(buf, "%u\n",
jiffies_to_msecs(atomic_read(&trigger_data->interval)));
}
static ssize_t interval_store(struct device *dev,
struct device_attribute *attr, const char *buf,
size_t size)
{
struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
unsigned long value;
int ret;
ret = kstrtoul(buf, 0, &value);
if (ret)
return ret;
/* impose some basic bounds on the timer interval */
if (value >= 5 && value <= 10000) {
cancel_delayed_work_sync(&trigger_data->work);
atomic_set(&trigger_data->interval, msecs_to_jiffies(value));
set_baseline_state(trigger_data); /* resets timer */
}
return size;
}
static DEVICE_ATTR_RW(interval);
static struct attribute *netdev_trig_attrs[] = {
&dev_attr_device_name.attr,
&dev_attr_link.attr,
&dev_attr_rx.attr,
&dev_attr_tx.attr,
&dev_attr_interval.attr,
NULL
};
ATTRIBUTE_GROUPS(netdev_trig);
static int netdev_trig_notify(struct notifier_block *nb,
unsigned long evt, void *dv)
{
struct net_device *dev =
netdev_notifier_info_to_dev((struct netdev_notifier_info *)dv);
struct led_netdev_data *trigger_data =
container_of(nb, struct led_netdev_data, notifier);
if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE
&& evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER)
return NOTIFY_DONE;
if (!(dev == trigger_data->net_dev ||
(evt == NETDEV_REGISTER && !strcmp(dev->name, trigger_data->device_name))))
return NOTIFY_DONE;
cancel_delayed_work_sync(&trigger_data->work);
spin_lock_bh(&trigger_data->lock);
clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
switch (evt) {
case NETDEV_REGISTER:
if (trigger_data->net_dev)
dev_put(trigger_data->net_dev);
dev_hold(dev);
trigger_data->net_dev = dev;
break;
case NETDEV_UNREGISTER:
dev_put(trigger_data->net_dev);
trigger_data->net_dev = NULL;
break;
case NETDEV_UP:
case NETDEV_CHANGE:
if (netif_carrier_ok(dev))
set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
break;
}
set_baseline_state(trigger_data);
spin_unlock_bh(&trigger_data->lock);
return NOTIFY_DONE;
}
/* here's the real work! */
static void netdev_trig_work(struct work_struct *work)
{
struct led_netdev_data *trigger_data =
container_of(work, struct led_netdev_data, work.work);
struct rtnl_link_stats64 *dev_stats;
unsigned int new_activity;
struct rtnl_link_stats64 temp;
unsigned long interval;
int invert;
/* If we dont have a device, insure we are off */
if (!trigger_data->net_dev) {
led_set_brightness(trigger_data->led_cdev, LED_OFF);
return;
}
/* If we are not looking for RX/TX then return */
if (!test_bit(NETDEV_LED_TX, &trigger_data->mode) &&
!test_bit(NETDEV_LED_RX, &trigger_data->mode))
return;
dev_stats = dev_get_stats(trigger_data->net_dev, &temp);
new_activity =
(test_bit(NETDEV_LED_TX, &trigger_data->mode) ?
dev_stats->tx_packets : 0) +
(test_bit(NETDEV_LED_RX, &trigger_data->mode) ?
dev_stats->rx_packets : 0);
if (trigger_data->last_activity != new_activity) {
led_stop_software_blink(trigger_data->led_cdev);
invert = test_bit(NETDEV_LED_LINK, &trigger_data->mode);
interval = jiffies_to_msecs(
atomic_read(&trigger_data->interval));
/* base state is ON (link present) */
led_blink_set_oneshot(trigger_data->led_cdev,
&interval,
&interval,
invert);
trigger_data->last_activity = new_activity;
}
schedule_delayed_work(&trigger_data->work,
(atomic_read(&trigger_data->interval)*2));
}
static int netdev_trig_activate(struct led_classdev *led_cdev)
{
struct led_netdev_data *trigger_data;
int rc;
trigger_data = kzalloc(sizeof(struct led_netdev_data), GFP_KERNEL);
if (!trigger_data)
return -ENOMEM;
spin_lock_init(&trigger_data->lock);
trigger_data->notifier.notifier_call = netdev_trig_notify;
trigger_data->notifier.priority = 10;
INIT_DELAYED_WORK(&trigger_data->work, netdev_trig_work);
trigger_data->led_cdev = led_cdev;
trigger_data->net_dev = NULL;
trigger_data->device_name[0] = 0;
trigger_data->mode = 0;
atomic_set(&trigger_data->interval, msecs_to_jiffies(50));
trigger_data->last_activity = 0;
led_set_trigger_data(led_cdev, trigger_data);
rc = register_netdevice_notifier(&trigger_data->notifier);
if (rc)
kfree(trigger_data);
return rc;
}
static void netdev_trig_deactivate(struct led_classdev *led_cdev)
{
struct led_netdev_data *trigger_data = led_get_trigger_data(led_cdev);
unregister_netdevice_notifier(&trigger_data->notifier);
cancel_delayed_work_sync(&trigger_data->work);
if (trigger_data->net_dev)
dev_put(trigger_data->net_dev);
kfree(trigger_data);
}
static struct led_trigger netdev_led_trigger = {
.name = "netdev",
.activate = netdev_trig_activate,
.deactivate = netdev_trig_deactivate,
.groups = netdev_trig_groups,
};
static int __init netdev_trig_init(void)
{
return led_trigger_register(&netdev_led_trigger);
}
static void __exit netdev_trig_exit(void)
{
led_trigger_unregister(&netdev_led_trigger);
}
module_init(netdev_trig_init);
module_exit(netdev_trig_exit);
MODULE_AUTHOR("Ben Whitten <ben.whitten@gmail.com>");
MODULE_AUTHOR("Oliver Jowett <oliver@opencloud.com>");
MODULE_DESCRIPTION("Netdev LED trigger");
MODULE_LICENSE("GPL v2");
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