1// SPDX-License-Identifier: GPL-2.0
  2// Copyright 2017 Ben Whitten <ben.whitten@gmail.com>
  3// Copyright 2007 Oliver Jowett <oliver@opencloud.com>
  4//
  5// LED Kernel Netdev Trigger
  6//
  7// Toggles the LED to reflect the link and traffic state of a named net device
  8//
  9// Derived from ledtrig-timer.c which is:
 10//  Copyright 2005-2006 Openedhand Ltd.
 11//  Author: Richard Purdie <rpurdie@openedhand.com>
 12
 13#include <linux/atomic.h>
 14#include <linux/ctype.h>
 15#include <linux/device.h>
 16#include <linux/init.h>
 17#include <linux/jiffies.h>
 18#include <linux/kernel.h>
 19#include <linux/leds.h>
 20#include <linux/list.h>
 21#include <linux/module.h>
 22#include <linux/netdevice.h>
 23#include <linux/spinlock.h>
 24#include <linux/timer.h>
 25#include "../leds.h"
 26
 27/*
 28 * Configurable sysfs attributes:
 29 *
 30 * device_name - network device name to monitor
 31 * interval - duration of LED blink, in milliseconds
 32 * link -  LED's normal state reflects whether the link is up
 33 *         (has carrier) or not
 34 * tx -  LED blinks on transmitted data
 35 * rx -  LED blinks on receive data
 36 *
 37 */
 38
 39struct led_netdev_data {
 40	spinlock_t lock;
 41
 42	struct delayed_work work;
 43	struct notifier_block notifier;
 44
 45	struct led_classdev *led_cdev;
 46	struct net_device *net_dev;
 47
 48	char device_name[IFNAMSIZ];
 49	atomic_t interval;
 50	unsigned int last_activity;
 51
 52	unsigned long mode;
 53#define NETDEV_LED_LINK	0
 54#define NETDEV_LED_TX	1
 55#define NETDEV_LED_RX	2
 56#define NETDEV_LED_MODE_LINKUP	3
 57};
 58
 59enum netdev_led_attr {
 60	NETDEV_ATTR_LINK,
 61	NETDEV_ATTR_TX,
 62	NETDEV_ATTR_RX
 63};
 64
 65static void set_baseline_state(struct led_netdev_data *trigger_data)
 66{
 67	int current_brightness;
 68	struct led_classdev *led_cdev = trigger_data->led_cdev;
 69
 70	current_brightness = led_cdev->brightness;
 71	if (current_brightness)
 72		led_cdev->blink_brightness = current_brightness;
 73	if (!led_cdev->blink_brightness)
 74		led_cdev->blink_brightness = led_cdev->max_brightness;
 75
 76	if (!test_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode))
 77		led_set_brightness(led_cdev, LED_OFF);
 78	else {
 79		if (test_bit(NETDEV_LED_LINK, &trigger_data->mode))
 80			led_set_brightness(led_cdev,
 81					   led_cdev->blink_brightness);
 82		else
 83			led_set_brightness(led_cdev, LED_OFF);
 84
 85		/* If we are looking for RX/TX start periodically
 86		 * checking stats
 87		 */
 88		if (test_bit(NETDEV_LED_TX, &trigger_data->mode) ||
 89		    test_bit(NETDEV_LED_RX, &trigger_data->mode))
 90			schedule_delayed_work(&trigger_data->work, 0);
 91	}
 92}
 93
 94static ssize_t device_name_show(struct device *dev,
 95				struct device_attribute *attr, char *buf)
 96{
 97	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
 98	ssize_t len;
 99
100	spin_lock_bh(&trigger_data->lock);
101	len = sprintf(buf, "%s\n", trigger_data->device_name);
102	spin_unlock_bh(&trigger_data->lock);
103
104	return len;
105}
106
107static ssize_t device_name_store(struct device *dev,
108				 struct device_attribute *attr, const char *buf,
109				 size_t size)
110{
111	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
112
113	if (size >= IFNAMSIZ)
114		return -EINVAL;
115
116	cancel_delayed_work_sync(&trigger_data->work);
117
118	spin_lock_bh(&trigger_data->lock);
119
120	if (trigger_data->net_dev) {
121		dev_put(trigger_data->net_dev);
122		trigger_data->net_dev = NULL;
123	}
124
125	memcpy(trigger_data->device_name, buf, size);
126	trigger_data->device_name[size] = 0;
127	if (size > 0 && trigger_data->device_name[size - 1] == '\n')
128		trigger_data->device_name[size - 1] = 0;
129
130	if (trigger_data->device_name[0] != 0)
131		trigger_data->net_dev =
132		    dev_get_by_name(&init_net, trigger_data->device_name);
133
134	clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
135	if (trigger_data->net_dev != NULL)
136		if (netif_carrier_ok(trigger_data->net_dev))
137			set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
138
139	trigger_data->last_activity = 0;
140
141	set_baseline_state(trigger_data);
142	spin_unlock_bh(&trigger_data->lock);
143
144	return size;
145}
146
147static DEVICE_ATTR_RW(device_name);
148
149static ssize_t netdev_led_attr_show(struct device *dev, char *buf,
150	enum netdev_led_attr attr)
151{
152	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
153	int bit;
154
155	switch (attr) {
156	case NETDEV_ATTR_LINK:
157		bit = NETDEV_LED_LINK;
158		break;
159	case NETDEV_ATTR_TX:
160		bit = NETDEV_LED_TX;
161		break;
162	case NETDEV_ATTR_RX:
163		bit = NETDEV_LED_RX;
164		break;
165	default:
166		return -EINVAL;
167	}
168
169	return sprintf(buf, "%u\n", test_bit(bit, &trigger_data->mode));
170}
171
172static ssize_t netdev_led_attr_store(struct device *dev, const char *buf,
173	size_t size, enum netdev_led_attr attr)
174{
175	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
176	unsigned long state;
177	int ret;
178	int bit;
179
180	ret = kstrtoul(buf, 0, &state);
181	if (ret)
182		return ret;
183
184	switch (attr) {
185	case NETDEV_ATTR_LINK:
186		bit = NETDEV_LED_LINK;
187		break;
188	case NETDEV_ATTR_TX:
189		bit = NETDEV_LED_TX;
190		break;
191	case NETDEV_ATTR_RX:
192		bit = NETDEV_LED_RX;
193		break;
194	default:
195		return -EINVAL;
196	}
197
198	cancel_delayed_work_sync(&trigger_data->work);
199
200	if (state)
201		set_bit(bit, &trigger_data->mode);
202	else
203		clear_bit(bit, &trigger_data->mode);
204
205	set_baseline_state(trigger_data);
206
207	return size;
208}
209
210static ssize_t link_show(struct device *dev,
211	struct device_attribute *attr, char *buf)
212{
213	return netdev_led_attr_show(dev, buf, NETDEV_ATTR_LINK);
214}
215
216static ssize_t link_store(struct device *dev,
217	struct device_attribute *attr, const char *buf, size_t size)
218{
219	return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_LINK);
220}
221
222static DEVICE_ATTR_RW(link);
223
224static ssize_t tx_show(struct device *dev,
225	struct device_attribute *attr, char *buf)
226{
227	return netdev_led_attr_show(dev, buf, NETDEV_ATTR_TX);
228}
229
230static ssize_t tx_store(struct device *dev,
231	struct device_attribute *attr, const char *buf, size_t size)
232{
233	return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_TX);
234}
235
236static DEVICE_ATTR_RW(tx);
237
238static ssize_t rx_show(struct device *dev,
239	struct device_attribute *attr, char *buf)
240{
241	return netdev_led_attr_show(dev, buf, NETDEV_ATTR_RX);
242}
243
244static ssize_t rx_store(struct device *dev,
245	struct device_attribute *attr, const char *buf, size_t size)
246{
247	return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_RX);
248}
249
250static DEVICE_ATTR_RW(rx);
251
252static ssize_t interval_show(struct device *dev,
253			     struct device_attribute *attr, char *buf)
254{
255	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
256
257	return sprintf(buf, "%u\n",
258		       jiffies_to_msecs(atomic_read(&trigger_data->interval)));
259}
260
261static ssize_t interval_store(struct device *dev,
262			      struct device_attribute *attr, const char *buf,
263			      size_t size)
264{
265	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
266	unsigned long value;
267	int ret;
268
269	ret = kstrtoul(buf, 0, &value);
270	if (ret)
271		return ret;
272
273	/* impose some basic bounds on the timer interval */
274	if (value >= 5 && value <= 10000) {
275		cancel_delayed_work_sync(&trigger_data->work);
276
277		atomic_set(&trigger_data->interval, msecs_to_jiffies(value));
278		set_baseline_state(trigger_data);	/* resets timer */
279	}
280
281	return size;
282}
283
284static DEVICE_ATTR_RW(interval);
285
286static struct attribute *netdev_trig_attrs[] = {
287	&dev_attr_device_name.attr,
288	&dev_attr_link.attr,
289	&dev_attr_rx.attr,
290	&dev_attr_tx.attr,
291	&dev_attr_interval.attr,
292	NULL
293};
294ATTRIBUTE_GROUPS(netdev_trig);
295
296static int netdev_trig_notify(struct notifier_block *nb,
297			      unsigned long evt, void *dv)
298{
299	struct net_device *dev =
300		netdev_notifier_info_to_dev((struct netdev_notifier_info *)dv);
301	struct led_netdev_data *trigger_data =
302		container_of(nb, struct led_netdev_data, notifier);
303
304	if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE
305	    && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER
306	    && evt != NETDEV_CHANGENAME)
307		return NOTIFY_DONE;
308
309	if (!(dev == trigger_data->net_dev ||
310	      (evt == NETDEV_CHANGENAME && !strcmp(dev->name, trigger_data->device_name)) ||
311	      (evt == NETDEV_REGISTER && !strcmp(dev->name, trigger_data->device_name))))
312		return NOTIFY_DONE;
313
314	cancel_delayed_work_sync(&trigger_data->work);
315
316	spin_lock_bh(&trigger_data->lock);
317
318	clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
319	switch (evt) {
320	case NETDEV_CHANGENAME:
321	case NETDEV_REGISTER:
322		if (trigger_data->net_dev)
323			dev_put(trigger_data->net_dev);
324		dev_hold(dev);
325		trigger_data->net_dev = dev;
326		break;
327	case NETDEV_UNREGISTER:
328		dev_put(trigger_data->net_dev);
329		trigger_data->net_dev = NULL;
330		break;
331	case NETDEV_UP:
332	case NETDEV_CHANGE:
333		if (netif_carrier_ok(dev))
334			set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
335		break;
336	}
337
338	set_baseline_state(trigger_data);
339
340	spin_unlock_bh(&trigger_data->lock);
341
342	return NOTIFY_DONE;
343}
344
345/* here's the real work! */
346static void netdev_trig_work(struct work_struct *work)
347{
348	struct led_netdev_data *trigger_data =
349		container_of(work, struct led_netdev_data, work.work);
350	struct rtnl_link_stats64 *dev_stats;
351	unsigned int new_activity;
352	struct rtnl_link_stats64 temp;
353	unsigned long interval;
354	int invert;
355
356	/* If we dont have a device, insure we are off */
357	if (!trigger_data->net_dev) {
358		led_set_brightness(trigger_data->led_cdev, LED_OFF);
359		return;
360	}
361
362	/* If we are not looking for RX/TX then return  */
363	if (!test_bit(NETDEV_LED_TX, &trigger_data->mode) &&
364	    !test_bit(NETDEV_LED_RX, &trigger_data->mode))
365		return;
366
367	dev_stats = dev_get_stats(trigger_data->net_dev, &temp);
368	new_activity =
369	    (test_bit(NETDEV_LED_TX, &trigger_data->mode) ?
370		dev_stats->tx_packets : 0) +
371	    (test_bit(NETDEV_LED_RX, &trigger_data->mode) ?
372		dev_stats->rx_packets : 0);
373
374	if (trigger_data->last_activity != new_activity) {
375		led_stop_software_blink(trigger_data->led_cdev);
376
377		invert = test_bit(NETDEV_LED_LINK, &trigger_data->mode);
378		interval = jiffies_to_msecs(
379				atomic_read(&trigger_data->interval));
380		/* base state is ON (link present) */
381		led_blink_set_oneshot(trigger_data->led_cdev,
382				      &interval,
383				      &interval,
384				      invert);
385		trigger_data->last_activity = new_activity;
386	}
387
388	schedule_delayed_work(&trigger_data->work,
389			(atomic_read(&trigger_data->interval)*2));
390}
391
392static int netdev_trig_activate(struct led_classdev *led_cdev)
393{
394	struct led_netdev_data *trigger_data;
395	int rc;
396
397	trigger_data = kzalloc(sizeof(struct led_netdev_data), GFP_KERNEL);
398	if (!trigger_data)
399		return -ENOMEM;
400
401	spin_lock_init(&trigger_data->lock);
402
403	trigger_data->notifier.notifier_call = netdev_trig_notify;
404	trigger_data->notifier.priority = 10;
405
406	INIT_DELAYED_WORK(&trigger_data->work, netdev_trig_work);
407
408	trigger_data->led_cdev = led_cdev;
409	trigger_data->net_dev = NULL;
410	trigger_data->device_name[0] = 0;
411
412	trigger_data->mode = 0;
413	atomic_set(&trigger_data->interval, msecs_to_jiffies(50));
414	trigger_data->last_activity = 0;
415
416	led_set_trigger_data(led_cdev, trigger_data);
417
418	rc = register_netdevice_notifier(&trigger_data->notifier);
419	if (rc)
420		kfree(trigger_data);
421
422	return rc;
423}
424
425static void netdev_trig_deactivate(struct led_classdev *led_cdev)
426{
427	struct led_netdev_data *trigger_data = led_get_trigger_data(led_cdev);
428
429	unregister_netdevice_notifier(&trigger_data->notifier);
430
431	cancel_delayed_work_sync(&trigger_data->work);
432
433	if (trigger_data->net_dev)
434		dev_put(trigger_data->net_dev);
435
436	kfree(trigger_data);
437}
438
439static struct led_trigger netdev_led_trigger = {
440	.name = "netdev",
441	.activate = netdev_trig_activate,
442	.deactivate = netdev_trig_deactivate,
443	.groups = netdev_trig_groups,
444};
445
446static int __init netdev_trig_init(void)
447{
448	return led_trigger_register(&netdev_led_trigger);
449}
450
451static void __exit netdev_trig_exit(void)
452{
453	led_trigger_unregister(&netdev_led_trigger);
454}
455
456module_init(netdev_trig_init);
457module_exit(netdev_trig_exit);
458
459MODULE_AUTHOR("Ben Whitten <ben.whitten@gmail.com>");
460MODULE_AUTHOR("Oliver Jowett <oliver@opencloud.com>");
461MODULE_DESCRIPTION("Netdev LED trigger");
462MODULE_LICENSE("GPL v2");