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_classdev *led_cdev = dev_get_drvdata(dev);
98 	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
99 	ssize_t len;
100 
101 	spin_lock_bh(&trigger_data->lock);
102 	len = sprintf(buf, "%s\n", trigger_data->device_name);
103 	spin_unlock_bh(&trigger_data->lock);
104 
105 	return len;
106 }
107 
108 static ssize_t device_name_store(struct device *dev,
109 				 struct device_attribute *attr, const char *buf,
110 				 size_t size)
111 {
112 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
113 	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
114 
115 	if (size >= IFNAMSIZ)
116 		return -EINVAL;
117 
118 	cancel_delayed_work_sync(&trigger_data->work);
119 
120 	spin_lock_bh(&trigger_data->lock);
121 
122 	if (trigger_data->net_dev) {
123 		dev_put(trigger_data->net_dev);
124 		trigger_data->net_dev = NULL;
125 	}
126 
127 	strncpy(trigger_data->device_name, buf, size);
128 	if (size > 0 && trigger_data->device_name[size - 1] == '\n')
129 		trigger_data->device_name[size - 1] = 0;
130 
131 	if (trigger_data->device_name[0] != 0)
132 		trigger_data->net_dev =
133 		    dev_get_by_name(&init_net, trigger_data->device_name);
134 
135 	clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
136 	if (trigger_data->net_dev != NULL)
137 		if (netif_carrier_ok(trigger_data->net_dev))
138 			set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
139 
140 	trigger_data->last_activity = 0;
141 
142 	set_baseline_state(trigger_data);
143 	spin_unlock_bh(&trigger_data->lock);
144 
145 	return size;
146 }
147 
148 static DEVICE_ATTR_RW(device_name);
149 
150 static ssize_t netdev_led_attr_show(struct device *dev, char *buf,
151 	enum netdev_led_attr attr)
152 {
153 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
154 	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
155 	int bit;
156 
157 	switch (attr) {
158 	case NETDEV_ATTR_LINK:
159 		bit = NETDEV_LED_LINK;
160 		break;
161 	case NETDEV_ATTR_TX:
162 		bit = NETDEV_LED_TX;
163 		break;
164 	case NETDEV_ATTR_RX:
165 		bit = NETDEV_LED_RX;
166 		break;
167 	default:
168 		return -EINVAL;
169 	}
170 
171 	return sprintf(buf, "%u\n", test_bit(bit, &trigger_data->mode));
172 }
173 
174 static ssize_t netdev_led_attr_store(struct device *dev, const char *buf,
175 	size_t size, enum netdev_led_attr attr)
176 {
177 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
178 	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
179 	unsigned long state;
180 	int ret;
181 	int bit;
182 
183 	ret = kstrtoul(buf, 0, &state);
184 	if (ret)
185 		return ret;
186 
187 	switch (attr) {
188 	case NETDEV_ATTR_LINK:
189 		bit = NETDEV_LED_LINK;
190 		break;
191 	case NETDEV_ATTR_TX:
192 		bit = NETDEV_LED_TX;
193 		break;
194 	case NETDEV_ATTR_RX:
195 		bit = NETDEV_LED_RX;
196 		break;
197 	default:
198 		return -EINVAL;
199 	}
200 
201 	cancel_delayed_work_sync(&trigger_data->work);
202 
203 	if (state)
204 		set_bit(bit, &trigger_data->mode);
205 	else
206 		clear_bit(bit, &trigger_data->mode);
207 
208 	set_baseline_state(trigger_data);
209 
210 	return size;
211 }
212 
213 static ssize_t link_show(struct device *dev,
214 	struct device_attribute *attr, char *buf)
215 {
216 	return netdev_led_attr_show(dev, buf, NETDEV_ATTR_LINK);
217 }
218 
219 static ssize_t link_store(struct device *dev,
220 	struct device_attribute *attr, const char *buf, size_t size)
221 {
222 	return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_LINK);
223 }
224 
225 static DEVICE_ATTR_RW(link);
226 
227 static ssize_t tx_show(struct device *dev,
228 	struct device_attribute *attr, char *buf)
229 {
230 	return netdev_led_attr_show(dev, buf, NETDEV_ATTR_TX);
231 }
232 
233 static ssize_t tx_store(struct device *dev,
234 	struct device_attribute *attr, const char *buf, size_t size)
235 {
236 	return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_TX);
237 }
238 
239 static DEVICE_ATTR_RW(tx);
240 
241 static ssize_t rx_show(struct device *dev,
242 	struct device_attribute *attr, char *buf)
243 {
244 	return netdev_led_attr_show(dev, buf, NETDEV_ATTR_RX);
245 }
246 
247 static ssize_t rx_store(struct device *dev,
248 	struct device_attribute *attr, const char *buf, size_t size)
249 {
250 	return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_RX);
251 }
252 
253 static DEVICE_ATTR_RW(rx);
254 
255 static ssize_t interval_show(struct device *dev,
256 			     struct device_attribute *attr, char *buf)
257 {
258 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
259 	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
260 
261 	return sprintf(buf, "%u\n",
262 		       jiffies_to_msecs(atomic_read(&trigger_data->interval)));
263 }
264 
265 static ssize_t interval_store(struct device *dev,
266 			      struct device_attribute *attr, const char *buf,
267 			      size_t size)
268 {
269 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
270 	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
271 	unsigned long value;
272 	int ret;
273 
274 	ret = kstrtoul(buf, 0, &value);
275 	if (ret)
276 		return ret;
277 
278 	/* impose some basic bounds on the timer interval */
279 	if (value >= 5 && value <= 10000) {
280 		cancel_delayed_work_sync(&trigger_data->work);
281 
282 		atomic_set(&trigger_data->interval, msecs_to_jiffies(value));
283 		set_baseline_state(trigger_data);	/* resets timer */
284 	}
285 
286 	return size;
287 }
288 
289 static DEVICE_ATTR_RW(interval);
290 
291 static int netdev_trig_notify(struct notifier_block *nb,
292 			      unsigned long evt, void *dv)
293 {
294 	struct net_device *dev =
295 		netdev_notifier_info_to_dev((struct netdev_notifier_info *)dv);
296 	struct led_netdev_data *trigger_data = container_of(nb,
297 							    struct
298 							    led_netdev_data,
299 							    notifier);
300 
301 	if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE
302 	    && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER
303 	    && evt != NETDEV_CHANGENAME)
304 		return NOTIFY_DONE;
305 
306 	if (strcmp(dev->name, trigger_data->device_name))
307 		return NOTIFY_DONE;
308 
309 	cancel_delayed_work_sync(&trigger_data->work);
310 
311 	spin_lock_bh(&trigger_data->lock);
312 
313 	clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
314 	switch (evt) {
315 	case NETDEV_REGISTER:
316 		if (trigger_data->net_dev)
317 			dev_put(trigger_data->net_dev);
318 		dev_hold(dev);
319 		trigger_data->net_dev = dev;
320 		break;
321 	case NETDEV_CHANGENAME:
322 	case NETDEV_UNREGISTER:
323 		if (trigger_data->net_dev) {
324 			dev_put(trigger_data->net_dev);
325 			trigger_data->net_dev = NULL;
326 		}
327 		break;
328 	case NETDEV_UP:
329 	case NETDEV_CHANGE:
330 		if (netif_carrier_ok(dev))
331 			set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
332 		break;
333 	}
334 
335 	set_baseline_state(trigger_data);
336 
337 	spin_unlock_bh(&trigger_data->lock);
338 
339 	return NOTIFY_DONE;
340 }
341 
342 /* here's the real work! */
343 static void netdev_trig_work(struct work_struct *work)
344 {
345 	struct led_netdev_data *trigger_data = container_of(work,
346 							    struct
347 							    led_netdev_data,
348 							    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 void 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;
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_cdev->trigger_data = trigger_data;
416 
417 	rc = device_create_file(led_cdev->dev, &dev_attr_device_name);
418 	if (rc)
419 		goto err_out;
420 	rc = device_create_file(led_cdev->dev, &dev_attr_link);
421 	if (rc)
422 		goto err_out_device_name;
423 	rc = device_create_file(led_cdev->dev, &dev_attr_rx);
424 	if (rc)
425 		goto err_out_link;
426 	rc = device_create_file(led_cdev->dev, &dev_attr_tx);
427 	if (rc)
428 		goto err_out_rx;
429 	rc = device_create_file(led_cdev->dev, &dev_attr_interval);
430 	if (rc)
431 		goto err_out_tx;
432 	rc = register_netdevice_notifier(&trigger_data->notifier);
433 	if (rc)
434 		goto err_out_interval;
435 	return;
436 
437 err_out_interval:
438 	device_remove_file(led_cdev->dev, &dev_attr_interval);
439 err_out_tx:
440 	device_remove_file(led_cdev->dev, &dev_attr_tx);
441 err_out_rx:
442 	device_remove_file(led_cdev->dev, &dev_attr_rx);
443 err_out_link:
444 	device_remove_file(led_cdev->dev, &dev_attr_link);
445 err_out_device_name:
446 	device_remove_file(led_cdev->dev, &dev_attr_device_name);
447 err_out:
448 	led_cdev->trigger_data = NULL;
449 	kfree(trigger_data);
450 }
451 
452 static void netdev_trig_deactivate(struct led_classdev *led_cdev)
453 {
454 	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
455 
456 	if (trigger_data) {
457 		unregister_netdevice_notifier(&trigger_data->notifier);
458 
459 		device_remove_file(led_cdev->dev, &dev_attr_device_name);
460 		device_remove_file(led_cdev->dev, &dev_attr_link);
461 		device_remove_file(led_cdev->dev, &dev_attr_rx);
462 		device_remove_file(led_cdev->dev, &dev_attr_tx);
463 		device_remove_file(led_cdev->dev, &dev_attr_interval);
464 
465 		cancel_delayed_work_sync(&trigger_data->work);
466 
467 		if (trigger_data->net_dev)
468 			dev_put(trigger_data->net_dev);
469 
470 		kfree(trigger_data);
471 	}
472 }
473 
474 static struct led_trigger netdev_led_trigger = {
475 	.name = "netdev",
476 	.activate = netdev_trig_activate,
477 	.deactivate = netdev_trig_deactivate,
478 };
479 
480 static int __init netdev_trig_init(void)
481 {
482 	return led_trigger_register(&netdev_led_trigger);
483 }
484 
485 static void __exit netdev_trig_exit(void)
486 {
487 	led_trigger_unregister(&netdev_led_trigger);
488 }
489 
490 module_init(netdev_trig_init);
491 module_exit(netdev_trig_exit);
492 
493 MODULE_AUTHOR("Ben Whitten <ben.whitten@gmail.com>");
494 MODULE_AUTHOR("Oliver Jowett <oliver@opencloud.com>");
495 MODULE_DESCRIPTION("Netdev LED trigger");
496 MODULE_LICENSE("GPL v2");
497