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17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19#include <linux/module.h>
20#include <linux/timer.h>
21#include <linux/alarmtimer.h>
22#include <linux/list.h>
23#include <linux/mutex.h>
24#include <linux/netfilter.h>
25#include <linux/netfilter/x_tables.h>
26#include <linux/netfilter/xt_IDLETIMER.h>
27#include <linux/kdev_t.h>
28#include <linux/kobject.h>
29#include <linux/workqueue.h>
30#include <linux/sysfs.h>
31
32struct idletimer_tg {
33 struct list_head entry;
34 struct alarm alarm;
35 struct timer_list timer;
36 struct work_struct work;
37
38 struct kobject *kobj;
39 struct device_attribute attr;
40
41 unsigned int refcnt;
42 u8 timer_type;
43};
44
45static LIST_HEAD(idletimer_tg_list);
46static DEFINE_MUTEX(list_mutex);
47
48static struct kobject *idletimer_tg_kobj;
49
50static
51struct idletimer_tg *__idletimer_tg_find_by_label(const char *label)
52{
53 struct idletimer_tg *entry;
54
55 list_for_each_entry(entry, &idletimer_tg_list, entry) {
56 if (!strcmp(label, entry->attr.attr.name))
57 return entry;
58 }
59
60 return NULL;
61}
62
63static ssize_t idletimer_tg_show(struct device *dev,
64 struct device_attribute *attr, char *buf)
65{
66 struct idletimer_tg *timer;
67 unsigned long expires = 0;
68 struct timespec64 ktimespec = {};
69 long time_diff = 0;
70
71 mutex_lock(&list_mutex);
72
73 timer = __idletimer_tg_find_by_label(attr->attr.name);
74 if (timer) {
75 if (timer->timer_type & XT_IDLETIMER_ALARM) {
76 ktime_t expires_alarm = alarm_expires_remaining(&timer->alarm);
77 ktimespec = ktime_to_timespec64(expires_alarm);
78 time_diff = ktimespec.tv_sec;
79 } else {
80 expires = timer->timer.expires;
81 time_diff = jiffies_to_msecs(expires - jiffies) / 1000;
82 }
83 }
84
85 mutex_unlock(&list_mutex);
86
87 if (time_after(expires, jiffies) || ktimespec.tv_sec > 0)
88 return snprintf(buf, PAGE_SIZE, "%ld\n", time_diff);
89
90 return snprintf(buf, PAGE_SIZE, "0\n");
91}
92
93static void idletimer_tg_work(struct work_struct *work)
94{
95 struct idletimer_tg *timer = container_of(work, struct idletimer_tg,
96 work);
97
98 sysfs_notify(idletimer_tg_kobj, NULL, timer->attr.attr.name);
99}
100
101static void idletimer_tg_expired(struct timer_list *t)
102{
103 struct idletimer_tg *timer = from_timer(timer, t, timer);
104
105 pr_debug("timer %s expired\n", timer->attr.attr.name);
106
107 schedule_work(&timer->work);
108}
109
110static enum alarmtimer_restart idletimer_tg_alarmproc(struct alarm *alarm,
111 ktime_t now)
112{
113 struct idletimer_tg *timer = alarm->data;
114
115 pr_debug("alarm %s expired\n", timer->attr.attr.name);
116 schedule_work(&timer->work);
117 return ALARMTIMER_NORESTART;
118}
119
120static int idletimer_check_sysfs_name(const char *name, unsigned int size)
121{
122 int ret;
123
124 ret = xt_check_proc_name(name, size);
125 if (ret < 0)
126 return ret;
127
128 if (!strcmp(name, "power") ||
129 !strcmp(name, "subsystem") ||
130 !strcmp(name, "uevent"))
131 return -EINVAL;
132
133 return 0;
134}
135
136static int idletimer_tg_create(struct idletimer_tg_info *info)
137{
138 int ret;
139
140 info->timer = kzalloc(sizeof(*info->timer), GFP_KERNEL);
141 if (!info->timer) {
142 ret = -ENOMEM;
143 goto out;
144 }
145
146 ret = idletimer_check_sysfs_name(info->label, sizeof(info->label));
147 if (ret < 0)
148 goto out_free_timer;
149
150 sysfs_attr_init(&info->timer->attr.attr);
151 info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL);
152 if (!info->timer->attr.attr.name) {
153 ret = -ENOMEM;
154 goto out_free_timer;
155 }
156 info->timer->attr.attr.mode = 0444;
157 info->timer->attr.show = idletimer_tg_show;
158
159 ret = sysfs_create_file(idletimer_tg_kobj, &info->timer->attr.attr);
160 if (ret < 0) {
161 pr_debug("couldn't add file to sysfs");
162 goto out_free_attr;
163 }
164
165 list_add(&info->timer->entry, &idletimer_tg_list);
166
167 timer_setup(&info->timer->timer, idletimer_tg_expired, 0);
168 info->timer->refcnt = 1;
169
170 INIT_WORK(&info->timer->work, idletimer_tg_work);
171
172 mod_timer(&info->timer->timer,
173 msecs_to_jiffies(info->timeout * 1000) + jiffies);
174
175 return 0;
176
177out_free_attr:
178 kfree(info->timer->attr.attr.name);
179out_free_timer:
180 kfree(info->timer);
181out:
182 return ret;
183}
184
185static int idletimer_tg_create_v1(struct idletimer_tg_info_v1 *info)
186{
187 int ret;
188
189 info->timer = kmalloc(sizeof(*info->timer), GFP_KERNEL);
190 if (!info->timer) {
191 ret = -ENOMEM;
192 goto out;
193 }
194
195 ret = idletimer_check_sysfs_name(info->label, sizeof(info->label));
196 if (ret < 0)
197 goto out_free_timer;
198
199 sysfs_attr_init(&info->timer->attr.attr);
200 info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL);
201 if (!info->timer->attr.attr.name) {
202 ret = -ENOMEM;
203 goto out_free_timer;
204 }
205 info->timer->attr.attr.mode = 0444;
206 info->timer->attr.show = idletimer_tg_show;
207
208 ret = sysfs_create_file(idletimer_tg_kobj, &info->timer->attr.attr);
209 if (ret < 0) {
210 pr_debug("couldn't add file to sysfs");
211 goto out_free_attr;
212 }
213
214
215 kobject_uevent(idletimer_tg_kobj,KOBJ_ADD);
216
217 list_add(&info->timer->entry, &idletimer_tg_list);
218 pr_debug("timer type value is %u", info->timer_type);
219 info->timer->timer_type = info->timer_type;
220 info->timer->refcnt = 1;
221
222 INIT_WORK(&info->timer->work, idletimer_tg_work);
223
224 if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
225 ktime_t tout;
226 alarm_init(&info->timer->alarm, ALARM_BOOTTIME,
227 idletimer_tg_alarmproc);
228 info->timer->alarm.data = info->timer;
229 tout = ktime_set(info->timeout, 0);
230 alarm_start_relative(&info->timer->alarm, tout);
231 } else {
232 timer_setup(&info->timer->timer, idletimer_tg_expired, 0);
233 mod_timer(&info->timer->timer,
234 msecs_to_jiffies(info->timeout * 1000) + jiffies);
235 }
236
237 return 0;
238
239out_free_attr:
240 kfree(info->timer->attr.attr.name);
241out_free_timer:
242 kfree(info->timer);
243out:
244 return ret;
245}
246
247
248
249
250static unsigned int idletimer_tg_target(struct sk_buff *skb,
251 const struct xt_action_param *par)
252{
253 const struct idletimer_tg_info *info = par->targinfo;
254
255 pr_debug("resetting timer %s, timeout period %u\n",
256 info->label, info->timeout);
257
258 mod_timer(&info->timer->timer,
259 msecs_to_jiffies(info->timeout * 1000) + jiffies);
260
261 return XT_CONTINUE;
262}
263
264
265
266
267static unsigned int idletimer_tg_target_v1(struct sk_buff *skb,
268 const struct xt_action_param *par)
269{
270 const struct idletimer_tg_info_v1 *info = par->targinfo;
271
272 pr_debug("resetting timer %s, timeout period %u\n",
273 info->label, info->timeout);
274
275 if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
276 ktime_t tout = ktime_set(info->timeout, 0);
277 alarm_start_relative(&info->timer->alarm, tout);
278 } else {
279 mod_timer(&info->timer->timer,
280 msecs_to_jiffies(info->timeout * 1000) + jiffies);
281 }
282
283 return XT_CONTINUE;
284}
285
286static int idletimer_tg_helper(struct idletimer_tg_info *info)
287{
288 if (info->timeout == 0) {
289 pr_debug("timeout value is zero\n");
290 return -EINVAL;
291 }
292 if (info->timeout >= INT_MAX / 1000) {
293 pr_debug("timeout value is too big\n");
294 return -EINVAL;
295 }
296 if (info->label[0] == '\0' ||
297 strnlen(info->label,
298 MAX_IDLETIMER_LABEL_SIZE) == MAX_IDLETIMER_LABEL_SIZE) {
299 pr_debug("label is empty or not nul-terminated\n");
300 return -EINVAL;
301 }
302 return 0;
303}
304
305
306static int idletimer_tg_checkentry(const struct xt_tgchk_param *par)
307{
308 struct idletimer_tg_info *info = par->targinfo;
309 int ret;
310
311 pr_debug("checkentry targinfo%s\n", info->label);
312
313 ret = idletimer_tg_helper(info);
314 if(ret < 0)
315 {
316 pr_debug("checkentry helper return invalid\n");
317 return -EINVAL;
318 }
319 mutex_lock(&list_mutex);
320
321 info->timer = __idletimer_tg_find_by_label(info->label);
322 if (info->timer) {
323 info->timer->refcnt++;
324 mod_timer(&info->timer->timer,
325 msecs_to_jiffies(info->timeout * 1000) + jiffies);
326
327 pr_debug("increased refcnt of timer %s to %u\n",
328 info->label, info->timer->refcnt);
329 } else {
330 ret = idletimer_tg_create(info);
331 if (ret < 0) {
332 pr_debug("failed to create timer\n");
333 mutex_unlock(&list_mutex);
334 return ret;
335 }
336 }
337
338 mutex_unlock(&list_mutex);
339 return 0;
340}
341
342static int idletimer_tg_checkentry_v1(const struct xt_tgchk_param *par)
343{
344 struct idletimer_tg_info_v1 *info = par->targinfo;
345 int ret;
346
347 pr_debug("checkentry targinfo%s\n", info->label);
348
349 if (info->send_nl_msg)
350 return -EOPNOTSUPP;
351
352 ret = idletimer_tg_helper((struct idletimer_tg_info *)info);
353 if(ret < 0)
354 {
355 pr_debug("checkentry helper return invalid\n");
356 return -EINVAL;
357 }
358
359 if (info->timer_type > XT_IDLETIMER_ALARM) {
360 pr_debug("invalid value for timer type\n");
361 return -EINVAL;
362 }
363
364 mutex_lock(&list_mutex);
365
366 info->timer = __idletimer_tg_find_by_label(info->label);
367 if (info->timer) {
368 if (info->timer->timer_type != info->timer_type) {
369 pr_debug("Adding/Replacing rule with same label and different timer type is not allowed\n");
370 mutex_unlock(&list_mutex);
371 return -EINVAL;
372 }
373
374 info->timer->refcnt++;
375 if (info->timer_type & XT_IDLETIMER_ALARM) {
376
377 ktime_t tout = alarm_expires_remaining(&info->timer->alarm);
378 struct timespec64 ktimespec = ktime_to_timespec64(tout);
379
380 if (ktimespec.tv_sec > 0) {
381 pr_debug("time_expiry_remaining %lld\n",
382 ktimespec.tv_sec);
383 alarm_start_relative(&info->timer->alarm, tout);
384 }
385 } else {
386 mod_timer(&info->timer->timer,
387 msecs_to_jiffies(info->timeout * 1000) + jiffies);
388 }
389 pr_debug("increased refcnt of timer %s to %u\n",
390 info->label, info->timer->refcnt);
391 } else {
392 ret = idletimer_tg_create_v1(info);
393 if (ret < 0) {
394 pr_debug("failed to create timer\n");
395 mutex_unlock(&list_mutex);
396 return ret;
397 }
398 }
399
400 mutex_unlock(&list_mutex);
401 return 0;
402}
403
404static void idletimer_tg_destroy(const struct xt_tgdtor_param *par)
405{
406 const struct idletimer_tg_info *info = par->targinfo;
407
408 pr_debug("destroy targinfo %s\n", info->label);
409
410 mutex_lock(&list_mutex);
411
412 if (--info->timer->refcnt == 0) {
413 pr_debug("deleting timer %s\n", info->label);
414
415 list_del(&info->timer->entry);
416 del_timer_sync(&info->timer->timer);
417 cancel_work_sync(&info->timer->work);
418 sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr);
419 kfree(info->timer->attr.attr.name);
420 kfree(info->timer);
421 } else {
422 pr_debug("decreased refcnt of timer %s to %u\n",
423 info->label, info->timer->refcnt);
424 }
425
426 mutex_unlock(&list_mutex);
427}
428
429static void idletimer_tg_destroy_v1(const struct xt_tgdtor_param *par)
430{
431 const struct idletimer_tg_info_v1 *info = par->targinfo;
432
433 pr_debug("destroy targinfo %s\n", info->label);
434
435 mutex_lock(&list_mutex);
436
437 if (--info->timer->refcnt == 0) {
438 pr_debug("deleting timer %s\n", info->label);
439
440 list_del(&info->timer->entry);
441 if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
442 alarm_cancel(&info->timer->alarm);
443 } else {
444 del_timer_sync(&info->timer->timer);
445 }
446 cancel_work_sync(&info->timer->work);
447 sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr);
448 kfree(info->timer->attr.attr.name);
449 kfree(info->timer);
450 } else {
451 pr_debug("decreased refcnt of timer %s to %u\n",
452 info->label, info->timer->refcnt);
453 }
454
455 mutex_unlock(&list_mutex);
456}
457
458
459static struct xt_target idletimer_tg[] __read_mostly = {
460 {
461 .name = "IDLETIMER",
462 .family = NFPROTO_UNSPEC,
463 .target = idletimer_tg_target,
464 .targetsize = sizeof(struct idletimer_tg_info),
465 .usersize = offsetof(struct idletimer_tg_info, timer),
466 .checkentry = idletimer_tg_checkentry,
467 .destroy = idletimer_tg_destroy,
468 .me = THIS_MODULE,
469 },
470 {
471 .name = "IDLETIMER",
472 .family = NFPROTO_UNSPEC,
473 .revision = 1,
474 .target = idletimer_tg_target_v1,
475 .targetsize = sizeof(struct idletimer_tg_info_v1),
476 .usersize = offsetof(struct idletimer_tg_info_v1, timer),
477 .checkentry = idletimer_tg_checkentry_v1,
478 .destroy = idletimer_tg_destroy_v1,
479 .me = THIS_MODULE,
480 },
481
482
483};
484
485static struct class *idletimer_tg_class;
486
487static struct device *idletimer_tg_device;
488
489static int __init idletimer_tg_init(void)
490{
491 int err;
492
493 idletimer_tg_class = class_create(THIS_MODULE, "xt_idletimer");
494 err = PTR_ERR(idletimer_tg_class);
495 if (IS_ERR(idletimer_tg_class)) {
496 pr_debug("couldn't register device class\n");
497 goto out;
498 }
499
500 idletimer_tg_device = device_create(idletimer_tg_class, NULL,
501 MKDEV(0, 0), NULL, "timers");
502 err = PTR_ERR(idletimer_tg_device);
503 if (IS_ERR(idletimer_tg_device)) {
504 pr_debug("couldn't register system device\n");
505 goto out_class;
506 }
507
508 idletimer_tg_kobj = &idletimer_tg_device->kobj;
509
510 err = xt_register_targets(idletimer_tg, ARRAY_SIZE(idletimer_tg));
511
512 if (err < 0) {
513 pr_debug("couldn't register xt target\n");
514 goto out_dev;
515 }
516
517 return 0;
518out_dev:
519 device_destroy(idletimer_tg_class, MKDEV(0, 0));
520out_class:
521 class_destroy(idletimer_tg_class);
522out:
523 return err;
524}
525
526static void __exit idletimer_tg_exit(void)
527{
528 xt_unregister_targets(idletimer_tg, ARRAY_SIZE(idletimer_tg));
529
530 device_destroy(idletimer_tg_class, MKDEV(0, 0));
531 class_destroy(idletimer_tg_class);
532}
533
534module_init(idletimer_tg_init);
535module_exit(idletimer_tg_exit);
536
537MODULE_AUTHOR("Timo Teras <ext-timo.teras@nokia.com>");
538MODULE_AUTHOR("Luciano Coelho <luciano.coelho@nokia.com>");
539MODULE_DESCRIPTION("Xtables: idle time monitor");
540MODULE_LICENSE("GPL v2");
541MODULE_ALIAS("ipt_IDLETIMER");
542MODULE_ALIAS("ip6t_IDLETIMER");
543
