drivers/leds/trigger/ledtrig-netdev.c

   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/mutex.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         struct mutex 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         bool carrier_link_up;
  54 };
  55
  56 enum led_trigger_netdev_modes {
  57         TRIGGER_NETDEV_LINK = 0,
  58         TRIGGER_NETDEV_TX,
  59         TRIGGER_NETDEV_RX,
  60
  61         /* Keep last */
  62         __TRIGGER_NETDEV_MAX,
  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 (!trigger_data->carrier_link_up) {
  77                 led_set_brightness(led_cdev, LED_OFF);
  78         } else {
  79                 if (test_bit(TRIGGER_NETDEV_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(TRIGGER_NETDEV_TX, &trigger_data->mode) ||
  89                     test_bit(TRIGGER_NETDEV_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         mutex_lock(&trigger_data->lock);
 101         len = sprintf(buf, "%s\n", trigger_data->device_name);
 102         mutex_unlock(&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         mutex_lock(&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         trigger_data->carrier_link_up = false;
 135         if (trigger_data->net_dev != NULL)
 136                 trigger_data->carrier_link_up = netif_carrier_ok(trigger_data->net_dev);
 137
 138         trigger_data->last_activity = 0;
 139
 140         set_baseline_state(trigger_data);
 141         mutex_unlock(&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 led_trigger_netdev_modes attr)
 150 {
 151         struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
 152         int bit;
 153
 154         switch (attr) {
 155         case TRIGGER_NETDEV_LINK:
 156         case TRIGGER_NETDEV_TX:
 157         case TRIGGER_NETDEV_RX:
 158                 bit = attr;
 159                 break;
 160         default:
 161                 return -EINVAL;
 162         }
 163
 164         return sprintf(buf, "%u\n", test_bit(bit, &trigger_data->mode));
 165 }
 166
 167 static ssize_t netdev_led_attr_store(struct device *dev, const char *buf,
 168                                      size_t size, enum led_trigger_netdev_modes attr)
 169 {
 170         struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
 171         unsigned long state;
 172         int ret;
 173         int bit;
 174
 175         ret = kstrtoul(buf, 0, &state);
 176         if (ret)
 177                 return ret;
 178
 179         switch (attr) {
 180         case TRIGGER_NETDEV_LINK:
 181         case TRIGGER_NETDEV_TX:
 182         case TRIGGER_NETDEV_RX:
 183                 bit = attr;
 184                 break;
 185         default:
 186                 return -EINVAL;
 187         }
 188
 189         cancel_delayed_work_sync(&trigger_data->work);
 190
 191         if (state)
 192                 set_bit(bit, &trigger_data->mode);
 193         else
 194                 clear_bit(bit, &trigger_data->mode);
 195
 196         set_baseline_state(trigger_data);
 197
 198         return size;
 199 }
 200
 201 #define DEFINE_NETDEV_TRIGGER(trigger_name, trigger) \
 202         static ssize_t trigger_name##_show(struct device *dev, \
 203                 struct device_attribute *attr, char *buf) \
 204         { \
 205                 return netdev_led_attr_show(dev, buf, trigger); \
 206         } \
 207         static ssize_t trigger_name##_store(struct device *dev, \
 208                 struct device_attribute *attr, const char *buf, size_t size) \
 209         { \
 210                 return netdev_led_attr_store(dev, buf, size, trigger); \
 211         } \
 212         static DEVICE_ATTR_RW(trigger_name)
 213
 214 DEFINE_NETDEV_TRIGGER(link, TRIGGER_NETDEV_LINK);
 215 DEFINE_NETDEV_TRIGGER(tx, TRIGGER_NETDEV_TX);
 216 DEFINE_NETDEV_TRIGGER(rx, TRIGGER_NETDEV_RX);
 217
 218 static ssize_t interval_show(struct device *dev,
 219                              struct device_attribute *attr, char *buf)
 220 {
 221         struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
 222
 223         return sprintf(buf, "%u\n",
 224                        jiffies_to_msecs(atomic_read(&trigger_data->interval)));
 225 }
 226
 227 static ssize_t interval_store(struct device *dev,
 228                               struct device_attribute *attr, const char *buf,
 229                               size_t size)
 230 {
 231         struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
 232         unsigned long value;
 233         int ret;
 234
 235         ret = kstrtoul(buf, 0, &value);
 236         if (ret)
 237                 return ret;
 238
 239         /* impose some basic bounds on the timer interval */
 240         if (value >= 5 && value <= 10000) {
 241                 cancel_delayed_work_sync(&trigger_data->work);
 242
 243                 atomic_set(&trigger_data->interval, msecs_to_jiffies(value));
 244                 set_baseline_state(trigger_data);       /* resets timer */
 245         }
 246
 247         return size;
 248 }
 249
 250 static DEVICE_ATTR_RW(interval);
 251
 252 static struct attribute *netdev_trig_attrs[] = {
 253         &dev_attr_device_name.attr,
 254         &dev_attr_link.attr,
 255         &dev_attr_rx.attr,
 256         &dev_attr_tx.attr,
 257         &dev_attr_interval.attr,
 258         NULL
 259 };
 260 ATTRIBUTE_GROUPS(netdev_trig);
 261
 262 static int netdev_trig_notify(struct notifier_block *nb,
 263                               unsigned long evt, void *dv)
 264 {
 265         struct net_device *dev =
 266                 netdev_notifier_info_to_dev((struct netdev_notifier_info *)dv);
 267         struct led_netdev_data *trigger_data =
 268                 container_of(nb, struct led_netdev_data, notifier);
 269
 270         if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE
 271             && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER
 272             && evt != NETDEV_CHANGENAME)
 273                 return NOTIFY_DONE;
 274
 275         if (!(dev == trigger_data->net_dev ||
 276               (evt == NETDEV_CHANGENAME && !strcmp(dev->name, trigger_data->device_name)) ||
 277               (evt == NETDEV_REGISTER && !strcmp(dev->name, trigger_data->device_name))))
 278                 return NOTIFY_DONE;
 279
 280         cancel_delayed_work_sync(&trigger_data->work);
 281
 282         mutex_lock(&trigger_data->lock);
 283
 284         trigger_data->carrier_link_up = false;
 285         switch (evt) {
 286         case NETDEV_CHANGENAME:
 287                 trigger_data->carrier_link_up = netif_carrier_ok(dev);
 288                 fallthrough;
 289         case NETDEV_REGISTER:
 290                 dev_put(trigger_data->net_dev);
 291                 dev_hold(dev);
 292                 trigger_data->net_dev = dev;
 293                 break;
 294         case NETDEV_UNREGISTER:
 295                 dev_put(trigger_data->net_dev);
 296                 trigger_data->net_dev = NULL;
 297                 break;
 298         case NETDEV_UP:
 299         case NETDEV_CHANGE:
 300                 trigger_data->carrier_link_up = netif_carrier_ok(dev);
 301                 break;
 302         }
 303
 304         set_baseline_state(trigger_data);
 305
 306         mutex_unlock(&trigger_data->lock);
 307
 308         return NOTIFY_DONE;
 309 }
 310
 311 /* here's the real work! */
 312 static void netdev_trig_work(struct work_struct *work)
 313 {
 314         struct led_netdev_data *trigger_data =
 315                 container_of(work, struct led_netdev_data, work.work);
 316         struct rtnl_link_stats64 *dev_stats;
 317         unsigned int new_activity;
 318         struct rtnl_link_stats64 temp;
 319         unsigned long interval;
 320         int invert;
 321
 322         /* If we dont have a device, insure we are off */
 323         if (!trigger_data->net_dev) {
 324                 led_set_brightness(trigger_data->led_cdev, LED_OFF);
 325                 return;
 326         }
 327
 328         /* If we are not looking for RX/TX then return  */
 329         if (!test_bit(TRIGGER_NETDEV_TX, &trigger_data->mode) &&
 330             !test_bit(TRIGGER_NETDEV_RX, &trigger_data->mode))
 331                 return;
 332
 333         dev_stats = dev_get_stats(trigger_data->net_dev, &temp);
 334         new_activity =
 335             (test_bit(TRIGGER_NETDEV_TX, &trigger_data->mode) ?
 336                 dev_stats->tx_packets : 0) +
 337             (test_bit(TRIGGER_NETDEV_RX, &trigger_data->mode) ?
 338                 dev_stats->rx_packets : 0);
 339
 340         if (trigger_data->last_activity != new_activity) {
 341                 led_stop_software_blink(trigger_data->led_cdev);
 342
 343                 invert = test_bit(TRIGGER_NETDEV_LINK, &trigger_data->mode);
 344                 interval = jiffies_to_msecs(
 345                                 atomic_read(&trigger_data->interval));
 346                 /* base state is ON (link present) */
 347                 led_blink_set_oneshot(trigger_data->led_cdev,
 348                                       &interval,
 349                                       &interval,
 350                                       invert);
 351                 trigger_data->last_activity = new_activity;
 352         }
 353
 354         schedule_delayed_work(&trigger_data->work,
 355                         (atomic_read(&trigger_data->interval)*2));
 356 }
 357
 358 static int netdev_trig_activate(struct led_classdev *led_cdev)
 359 {
 360         struct led_netdev_data *trigger_data;
 361         int rc;
 362
 363         trigger_data = kzalloc(sizeof(struct led_netdev_data), GFP_KERNEL);
 364         if (!trigger_data)
 365                 return -ENOMEM;
 366
 367         mutex_init(&trigger_data->lock);
 368
 369         trigger_data->notifier.notifier_call = netdev_trig_notify;
 370         trigger_data->notifier.priority = 10;
 371
 372         INIT_DELAYED_WORK(&trigger_data->work, netdev_trig_work);
 373
 374         trigger_data->led_cdev = led_cdev;
 375         trigger_data->net_dev = NULL;
 376         trigger_data->device_name[0] = 0;
 377
 378         trigger_data->mode = 0;
 379         atomic_set(&trigger_data->interval, msecs_to_jiffies(50));
 380         trigger_data->last_activity = 0;
 381
 382         led_set_trigger_data(led_cdev, trigger_data);
 383
 384         rc = register_netdevice_notifier(&trigger_data->notifier);
 385         if (rc)
 386                 kfree(trigger_data);
 387
 388         return rc;
 389 }
 390
 391 static void netdev_trig_deactivate(struct led_classdev *led_cdev)
 392 {
 393         struct led_netdev_data *trigger_data = led_get_trigger_data(led_cdev);
 394
 395         unregister_netdevice_notifier(&trigger_data->notifier);
 396
 397         cancel_delayed_work_sync(&trigger_data->work);
 398
 399         dev_put(trigger_data->net_dev);
 400
 401         kfree(trigger_data);
 402 }
 403
 404 static struct led_trigger netdev_led_trigger = {
 405         .name = "netdev",
 406         .activate = netdev_trig_activate,
 407         .deactivate = netdev_trig_deactivate,
 408         .groups = netdev_trig_groups,
 409 };
 410
 411 static int __init netdev_trig_init(void)
 412 {
 413         return led_trigger_register(&netdev_led_trigger);
 414 }
 415
 416 static void __exit netdev_trig_exit(void)
 417 {
 418         led_trigger_unregister(&netdev_led_trigger);
 419 }
 420
 421 module_init(netdev_trig_init);
 422 module_exit(netdev_trig_exit);
 423
 424 MODULE_AUTHOR("Ben Whitten <ben.whitten@gmail.com>");
 425 MODULE_AUTHOR("Oliver Jowett <oliver@opencloud.com>");
 426 MODULE_DESCRIPTION("Netdev LED trigger");
 427 MODULE_LICENSE("GPL v2");