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 
39 struct 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 
59 enum netdev_led_attr {
60 	NETDEV_ATTR_LINK,
61 	NETDEV_ATTR_TX,
62 	NETDEV_ATTR_RX
63 };
64 
65 static 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 
94 static 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 
107 static 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 	strncpy(trigger_data->device_name, buf, size);
126 	if (size > 0 && trigger_data->device_name[size - 1] == '\n')
127 		trigger_data->device_name[size - 1] = 0;
128 
129 	if (trigger_data->device_name[0] != 0)
130 		trigger_data->net_dev =
131 		    dev_get_by_name(&init_net, trigger_data->device_name);
132 
133 	clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
134 	if (trigger_data->net_dev != NULL)
135 		if (netif_carrier_ok(trigger_data->net_dev))
136 			set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
137 
138 	trigger_data->last_activity = 0;
139 
140 	set_baseline_state(trigger_data);
141 	spin_unlock_bh(&trigger_data->lock);
142 
143 	return size;
144 }
145 
146 static DEVICE_ATTR_RW(device_name);
147 
148 static ssize_t netdev_led_attr_show(struct device *dev, char *buf,
149 	enum netdev_led_attr attr)
150 {
151 	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
152 	int bit;
153 
154 	switch (attr) {
155 	case NETDEV_ATTR_LINK:
156 		bit = NETDEV_LED_LINK;
157 		break;
158 	case NETDEV_ATTR_TX:
159 		bit = NETDEV_LED_TX;
160 		break;
161 	case NETDEV_ATTR_RX:
162 		bit = NETDEV_LED_RX;
163 		break;
164 	default:
165 		return -EINVAL;
166 	}
167 
168 	return sprintf(buf, "%u\n", test_bit(bit, &trigger_data->mode));
169 }
170 
171 static ssize_t netdev_led_attr_store(struct device *dev, const char *buf,
172 	size_t size, enum netdev_led_attr attr)
173 {
174 	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
175 	unsigned long state;
176 	int ret;
177 	int bit;
178 
179 	ret = kstrtoul(buf, 0, &state);
180 	if (ret)
181 		return ret;
182 
183 	switch (attr) {
184 	case NETDEV_ATTR_LINK:
185 		bit = NETDEV_LED_LINK;
186 		break;
187 	case NETDEV_ATTR_TX:
188 		bit = NETDEV_LED_TX;
189 		break;
190 	case NETDEV_ATTR_RX:
191 		bit = NETDEV_LED_RX;
192 		break;
193 	default:
194 		return -EINVAL;
195 	}
196 
197 	cancel_delayed_work_sync(&trigger_data->work);
198 
199 	if (state)
200 		set_bit(bit, &trigger_data->mode);
201 	else
202 		clear_bit(bit, &trigger_data->mode);
203 
204 	set_baseline_state(trigger_data);
205 
206 	return size;
207 }
208 
209 static ssize_t link_show(struct device *dev,
210 	struct device_attribute *attr, char *buf)
211 {
212 	return netdev_led_attr_show(dev, buf, NETDEV_ATTR_LINK);
213 }
214 
215 static ssize_t link_store(struct device *dev,
216 	struct device_attribute *attr, const char *buf, size_t size)
217 {
218 	return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_LINK);
219 }
220 
221 static DEVICE_ATTR_RW(link);
222 
223 static ssize_t tx_show(struct device *dev,
224 	struct device_attribute *attr, char *buf)
225 {
226 	return netdev_led_attr_show(dev, buf, NETDEV_ATTR_TX);
227 }
228 
229 static ssize_t tx_store(struct device *dev,
230 	struct device_attribute *attr, const char *buf, size_t size)
231 {
232 	return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_TX);
233 }
234 
235 static DEVICE_ATTR_RW(tx);
236 
237 static ssize_t rx_show(struct device *dev,
238 	struct device_attribute *attr, char *buf)
239 {
240 	return netdev_led_attr_show(dev, buf, NETDEV_ATTR_RX);
241 }
242 
243 static ssize_t rx_store(struct device *dev,
244 	struct device_attribute *attr, const char *buf, size_t size)
245 {
246 	return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_RX);
247 }
248 
249 static DEVICE_ATTR_RW(rx);
250 
251 static ssize_t interval_show(struct device *dev,
252 			     struct device_attribute *attr, char *buf)
253 {
254 	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
255 
256 	return sprintf(buf, "%u\n",
257 		       jiffies_to_msecs(atomic_read(&trigger_data->interval)));
258 }
259 
260 static ssize_t interval_store(struct device *dev,
261 			      struct device_attribute *attr, const char *buf,
262 			      size_t size)
263 {
264 	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
265 	unsigned long value;
266 	int ret;
267 
268 	ret = kstrtoul(buf, 0, &value);
269 	if (ret)
270 		return ret;
271 
272 	/* impose some basic bounds on the timer interval */
273 	if (value >= 5 && value <= 10000) {
274 		cancel_delayed_work_sync(&trigger_data->work);
275 
276 		atomic_set(&trigger_data->interval, msecs_to_jiffies(value));
277 		set_baseline_state(trigger_data);	/* resets timer */
278 	}
279 
280 	return size;
281 }
282 
283 static DEVICE_ATTR_RW(interval);
284 
285 static struct attribute *netdev_trig_attrs[] = {
286 	&dev_attr_device_name.attr,
287 	&dev_attr_link.attr,
288 	&dev_attr_rx.attr,
289 	&dev_attr_tx.attr,
290 	&dev_attr_interval.attr,
291 	NULL
292 };
293 ATTRIBUTE_GROUPS(netdev_trig);
294 
295 static int netdev_trig_notify(struct notifier_block *nb,
296 			      unsigned long evt, void *dv)
297 {
298 	struct net_device *dev =
299 		netdev_notifier_info_to_dev((struct netdev_notifier_info *)dv);
300 	struct led_netdev_data *trigger_data =
301 		container_of(nb, struct led_netdev_data, notifier);
302 
303 	if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE
304 	    && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER
305 	    && evt != NETDEV_CHANGENAME)
306 		return NOTIFY_DONE;
307 
308 	if (strcmp(dev->name, trigger_data->device_name))
309 		return NOTIFY_DONE;
310 
311 	cancel_delayed_work_sync(&trigger_data->work);
312 
313 	spin_lock_bh(&trigger_data->lock);
314 
315 	clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
316 	switch (evt) {
317 	case NETDEV_REGISTER:
318 		if (trigger_data->net_dev)
319 			dev_put(trigger_data->net_dev);
320 		dev_hold(dev);
321 		trigger_data->net_dev = dev;
322 		break;
323 	case NETDEV_CHANGENAME:
324 	case NETDEV_UNREGISTER:
325 		if (trigger_data->net_dev) {
326 			dev_put(trigger_data->net_dev);
327 			trigger_data->net_dev = NULL;
328 		}
329 		break;
330 	case NETDEV_UP:
331 	case NETDEV_CHANGE:
332 		if (netif_carrier_ok(dev))
333 			set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
334 		break;
335 	}
336 
337 	set_baseline_state(trigger_data);
338 
339 	spin_unlock_bh(&trigger_data->lock);
340 
341 	return NOTIFY_DONE;
342 }
343 
344 /* here's the real work! */
345 static void netdev_trig_work(struct work_struct *work)
346 {
347 	struct led_netdev_data *trigger_data =
348 		container_of(work, struct led_netdev_data, work.work);
349 	struct rtnl_link_stats64 *dev_stats;
350 	unsigned int new_activity;
351 	struct rtnl_link_stats64 temp;
352 	unsigned long interval;
353 	int invert;
354 
355 	/* If we dont have a device, insure we are off */
356 	if (!trigger_data->net_dev) {
357 		led_set_brightness(trigger_data->led_cdev, LED_OFF);
358 		return;
359 	}
360 
361 	/* If we are not looking for RX/TX then return  */
362 	if (!test_bit(NETDEV_LED_TX, &trigger_data->mode) &&
363 	    !test_bit(NETDEV_LED_RX, &trigger_data->mode))
364 		return;
365 
366 	dev_stats = dev_get_stats(trigger_data->net_dev, &temp);
367 	new_activity =
368 	    (test_bit(NETDEV_LED_TX, &trigger_data->mode) ?
369 		dev_stats->tx_packets : 0) +
370 	    (test_bit(NETDEV_LED_RX, &trigger_data->mode) ?
371 		dev_stats->rx_packets : 0);
372 
373 	if (trigger_data->last_activity != new_activity) {
374 		led_stop_software_blink(trigger_data->led_cdev);
375 
376 		invert = test_bit(NETDEV_LED_LINK, &trigger_data->mode);
377 		interval = jiffies_to_msecs(
378 				atomic_read(&trigger_data->interval));
379 		/* base state is ON (link present) */
380 		led_blink_set_oneshot(trigger_data->led_cdev,
381 				      &interval,
382 				      &interval,
383 				      invert);
384 		trigger_data->last_activity = new_activity;
385 	}
386 
387 	schedule_delayed_work(&trigger_data->work,
388 			(atomic_read(&trigger_data->interval)*2));
389 }
390 
391 static int netdev_trig_activate(struct led_classdev *led_cdev)
392 {
393 	struct led_netdev_data *trigger_data;
394 	int rc;
395 
396 	trigger_data = kzalloc(sizeof(struct led_netdev_data), GFP_KERNEL);
397 	if (!trigger_data)
398 		return -ENOMEM;
399 
400 	spin_lock_init(&trigger_data->lock);
401 
402 	trigger_data->notifier.notifier_call = netdev_trig_notify;
403 	trigger_data->notifier.priority = 10;
404 
405 	INIT_DELAYED_WORK(&trigger_data->work, netdev_trig_work);
406 
407 	trigger_data->led_cdev = led_cdev;
408 	trigger_data->net_dev = NULL;
409 	trigger_data->device_name[0] = 0;
410 
411 	trigger_data->mode = 0;
412 	atomic_set(&trigger_data->interval, msecs_to_jiffies(50));
413 	trigger_data->last_activity = 0;
414 
415 	led_set_trigger_data(led_cdev, trigger_data);
416 
417 	rc = register_netdevice_notifier(&trigger_data->notifier);
418 	if (rc)
419 		kfree(trigger_data);
420 
421 	return rc;
422 }
423 
424 static void netdev_trig_deactivate(struct led_classdev *led_cdev)
425 {
426 	struct led_netdev_data *trigger_data = led_get_trigger_data(led_cdev);
427 
428 	unregister_netdevice_notifier(&trigger_data->notifier);
429 
430 	cancel_delayed_work_sync(&trigger_data->work);
431 
432 	if (trigger_data->net_dev)
433 		dev_put(trigger_data->net_dev);
434 
435 	kfree(trigger_data);
436 }
437 
438 static struct led_trigger netdev_led_trigger = {
439 	.name = "netdev",
440 	.activate = netdev_trig_activate,
441 	.deactivate = netdev_trig_deactivate,
442 	.groups = netdev_trig_groups,
443 };
444 
445 static int __init netdev_trig_init(void)
446 {
447 	return led_trigger_register(&netdev_led_trigger);
448 }
449 
450 static void __exit netdev_trig_exit(void)
451 {
452 	led_trigger_unregister(&netdev_led_trigger);
453 }
454 
455 module_init(netdev_trig_init);
456 module_exit(netdev_trig_exit);
457 
458 MODULE_AUTHOR("Ben Whitten <ben.whitten@gmail.com>");
459 MODULE_AUTHOR("Oliver Jowett <oliver@opencloud.com>");
460 MODULE_DESCRIPTION("Netdev LED trigger");
461 MODULE_LICENSE("GPL v2");
462