summaryrefslogtreecommitdiffstats
path: root/net/netfilter/xt_IDLETIMER.c
blob: 7b2f359bfce46160acc3c29e7a9b4b68bbe3b731 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/net/netfilter/xt_IDLETIMER.c
 *
 * Netfilter module to trigger a timer when packet matches.
 * After timer expires a kevent will be sent.
 *
 * Copyright (C) 2004, 2010 Nokia Corporation
 * Written by Timo Teras <ext-timo.teras@nokia.com>
 *
 * Converted to x_tables and reworked for upstream inclusion
 * by Luciano Coelho <luciano.coelho@nokia.com>
 *
 * Contact: Luciano Coelho <luciano.coelho@nokia.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/timer.h>
#include <linux/alarmtimer.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/netfilter.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_IDLETIMER.h>
#include <linux/kdev_t.h>
#include <linux/kobject.h>
#include <linux/workqueue.h>
#include <linux/sysfs.h>

struct idletimer_tg {
	struct list_head entry;
	struct alarm alarm;
	struct timer_list timer;
	struct work_struct work;

	struct kobject *kobj;
	struct device_attribute attr;

	unsigned int refcnt;
	u8 timer_type;
};

static LIST_HEAD(idletimer_tg_list);
static DEFINE_MUTEX(list_mutex);

static struct kobject *idletimer_tg_kobj;

static
struct idletimer_tg *__idletimer_tg_find_by_label(const char *label)
{
	struct idletimer_tg *entry;

	list_for_each_entry(entry, &idletimer_tg_list, entry) {
		if (!strcmp(label, entry->attr.attr.name))
			return entry;
	}

	return NULL;
}

static ssize_t idletimer_tg_show(struct device *dev,
				 struct device_attribute *attr, char *buf)
{
	struct idletimer_tg *timer;
	unsigned long expires = 0;
	struct timespec64 ktimespec = {};
	long time_diff = 0;

	mutex_lock(&list_mutex);

	timer =	__idletimer_tg_find_by_label(attr->attr.name);
	if (timer) {
		if (timer->timer_type & XT_IDLETIMER_ALARM) {
			ktime_t expires_alarm = alarm_expires_remaining(&timer->alarm);
			ktimespec = ktime_to_timespec64(expires_alarm);
			time_diff = ktimespec.tv_sec;
		} else {
			expires = timer->timer.expires;
			time_diff = jiffies_to_msecs(expires - jiffies) / 1000;
		}
	}

	mutex_unlock(&list_mutex);

	if (time_after(expires, jiffies) || ktimespec.tv_sec > 0)
		return snprintf(buf, PAGE_SIZE, "%ld\n", time_diff);

	return snprintf(buf, PAGE_SIZE, "0\n");
}

static void idletimer_tg_work(struct work_struct *work)
{
	struct idletimer_tg *timer = container_of(work, struct idletimer_tg,
						  work);

	sysfs_notify(idletimer_tg_kobj, NULL, timer->attr.attr.name);
}

static void idletimer_tg_expired(struct timer_list *t)
{
	struct idletimer_tg *timer = from_timer(timer, t, timer);

	pr_debug("timer %s expired\n", timer->attr.attr.name);

	schedule_work(&timer->work);
}

static enum alarmtimer_restart idletimer_tg_alarmproc(struct alarm *alarm,
							  ktime_t now)
{
	struct idletimer_tg *timer = alarm->data;

	pr_debug("alarm %s expired\n", timer->attr.attr.name);
	schedule_work(&timer->work);
	return ALARMTIMER_NORESTART;
}

static int idletimer_check_sysfs_name(const char *name, unsigned int size)
{
	int ret;

	ret = xt_check_proc_name(name, size);
	if (ret < 0)
		return ret;

	if (!strcmp(name, "power") ||
	    !strcmp(name, "subsystem") ||
	    !strcmp(name, "uevent"))
		return -EINVAL;

	return 0;
}

static int idletimer_tg_create(struct idletimer_tg_info *info)
{
	int ret;

	info->timer = kmalloc(sizeof(*info->timer), GFP_KERNEL);
	if (!info->timer) {
		ret = -ENOMEM;
		goto out;
	}

	ret = idletimer_check_sysfs_name(info->label, sizeof(info->label));
	if (ret < 0)
		goto out_free_timer;

	sysfs_attr_init(&info->timer->attr.attr);
	info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL);
	if (!info->timer->attr.attr.name) {
		ret = -ENOMEM;
		goto out_free_timer;
	}
	info->timer->attr.attr.mode = 0444;
	info->timer->attr.show = idletimer_tg_show;

	ret = sysfs_create_file(idletimer_tg_kobj, &info->timer->attr.attr);
	if (ret < 0) {
		pr_debug("couldn't add file to sysfs");
		goto out_free_attr;
	}

	list_add(&info->timer->entry, &idletimer_tg_list);

	timer_setup(&info->timer->timer, idletimer_tg_expired, 0);
	info->timer->refcnt = 1;

	INIT_WORK(&info->timer->work, idletimer_tg_work);

	mod_timer(&info->timer->timer,
		  msecs_to_jiffies(info->timeout * 1000) + jiffies);

	return 0;

out_free_attr:
	kfree(info->timer->attr.attr.name);
out_free_timer:
	kfree(info->timer);
out:
	return ret;
}

static int idletimer_tg_create_v1(struct idletimer_tg_info_v1 *info)
{
	int ret;

	info->timer = kmalloc(sizeof(*info->timer), GFP_KERNEL);
	if (!info->timer) {
		ret = -ENOMEM;
		goto out;
	}

	ret = idletimer_check_sysfs_name(info->label, sizeof(info->label));
	if (ret < 0)
		goto out_free_timer;

	sysfs_attr_init(&info->timer->attr.attr);
	info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL);
	if (!info->timer->attr.attr.name) {
		ret = -ENOMEM;
		goto out_free_timer;
	}
	info->timer->attr.attr.mode = 0444;
	info->timer->attr.show = idletimer_tg_show;

	ret = sysfs_create_file(idletimer_tg_kobj, &info->timer->attr.attr);
	if (ret < 0) {
		pr_debug("couldn't add file to sysfs");
		goto out_free_attr;
	}

	/*  notify userspace  */
	kobject_uevent(idletimer_tg_kobj,KOBJ_ADD);

	list_add(&info->timer->entry, &idletimer_tg_list);
	pr_debug("timer type value is %u", info->timer_type);
	info->timer->timer_type = info->timer_type;
	info->timer->refcnt = 1;

	INIT_WORK(&info->timer->work, idletimer_tg_work);

	if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
		ktime_t tout;
		alarm_init(&info->timer->alarm, ALARM_BOOTTIME,
			   idletimer_tg_alarmproc);
		info->timer->alarm.data = info->timer;
		tout = ktime_set(info->timeout, 0);
		alarm_start_relative(&info->timer->alarm, tout);
	} else {
		timer_setup(&info->timer->timer, idletimer_tg_expired, 0);
		mod_timer(&info->timer->timer,
				msecs_to_jiffies(info->timeout * 1000) + jiffies);
	}

	return 0;

out_free_attr:
	kfree(info->timer->attr.attr.name);
out_free_timer:
	kfree(info->timer);
out:
	return ret;
}

/*
 * The actual xt_tables plugin.
 */
static unsigned int idletimer_tg_target(struct sk_buff *skb,
					 const struct xt_action_param *par)
{
	const struct idletimer_tg_info *info = par->targinfo;

	pr_debug("resetting timer %s, timeout period %u\n",
		 info->label, info->timeout);

	mod_timer(&info->timer->timer,
		  msecs_to_jiffies(info->timeout * 1000) + jiffies);

	return XT_CONTINUE;
}

/*
 * The actual xt_tables plugin.
 */
static unsigned int idletimer_tg_target_v1(struct sk_buff *skb,
					 const struct xt_action_param *par)
{
	const struct idletimer_tg_info_v1 *info = par->targinfo;

	pr_debug("resetting timer %s, timeout period %u\n",
		 info->label, info->timeout);

	if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
		ktime_t tout = ktime_set(info->timeout, 0);
		alarm_start_relative(&info->timer->alarm, tout);
	} else {
		mod_timer(&info->timer->timer,
				msecs_to_jiffies(info->timeout * 1000) + jiffies);
	}

	return XT_CONTINUE;
}

static int idletimer_tg_helper(struct idletimer_tg_info *info)
{
	if (info->timeout == 0) {
		pr_debug("timeout value is zero\n");
		return -EINVAL;
	}
	if (info->timeout >= INT_MAX / 1000) {
		pr_debug("timeout value is too big\n");
		return -EINVAL;
	}
	if (info->label[0] == '\0' ||
	    strnlen(info->label,
		    MAX_IDLETIMER_LABEL_SIZE) == MAX_IDLETIMER_LABEL_SIZE) {
		pr_debug("label is empty or not nul-terminated\n");
		return -EINVAL;
	}
	return 0;
}


static int idletimer_tg_checkentry(const struct xt_tgchk_param *par)
{
	struct idletimer_tg_info *info = par->targinfo;
	int ret;

	pr_debug("checkentry targinfo%s\n", info->label);

	ret = idletimer_tg_helper(info);
	if(ret < 0)
	{
		pr_debug("checkentry helper return invalid\n");
		return -EINVAL;
	}
	mutex_lock(&list_mutex);

	info->timer = __idletimer_tg_find_by_label(info->label);
	if (info->timer) {
		info->timer->refcnt++;
		mod_timer(&info->timer->timer,
			  msecs_to_jiffies(info->timeout * 1000) + jiffies);

		pr_debug("increased refcnt of timer %s to %u\n",
			 info->label, info->timer->refcnt);
	} else {
		ret = idletimer_tg_create(info);
		if (ret < 0) {
			pr_debug("failed to create timer\n");
			mutex_unlock(&list_mutex);
			return ret;
		}
	}

	mutex_unlock(&list_mutex);
	return 0;
}

static int idletimer_tg_checkentry_v1(const struct xt_tgchk_param *par)
{
	struct idletimer_tg_info_v1 *info = par->targinfo;
	int ret;

	pr_debug("checkentry targinfo%s\n", info->label);

	if (info->send_nl_msg)
		return -EOPNOTSUPP;

	ret = idletimer_tg_helper((struct idletimer_tg_info *)info);
	if(ret < 0)
	{
		pr_debug("checkentry helper return invalid\n");
		return -EINVAL;
	}

	if (info->timer_type > XT_IDLETIMER_ALARM) {
		pr_debug("invalid value for timer type\n");
		return -EINVAL;
	}

	mutex_lock(&list_mutex);

	info->timer = __idletimer_tg_find_by_label(info->label);
	if (info->timer) {
		if (info->timer->timer_type != info->timer_type) {
			pr_debug("Adding/Replacing rule with same label and different timer type is not allowed\n");
			mutex_unlock(&list_mutex);
			return -EINVAL;
		}

		info->timer->refcnt++;
		if (info->timer_type & XT_IDLETIMER_ALARM) {
			/* calculate remaining expiry time */
			ktime_t tout = alarm_expires_remaining(&info->timer->alarm);
			struct timespec64 ktimespec = ktime_to_timespec64(tout);

			if (ktimespec.tv_sec > 0) {
				pr_debug("time_expiry_remaining %lld\n",
					 ktimespec.tv_sec);
				alarm_start_relative(&info->timer->alarm, tout);
			}
		} else {
				mod_timer(&info->timer->timer,
					msecs_to_jiffies(info->timeout * 1000) + jiffies);
		}
		pr_debug("increased refcnt of timer %s to %u\n",
			 info->label, info->timer->refcnt);
	} else {
		ret = idletimer_tg_create_v1(info);
		if (ret < 0) {
			pr_debug("failed to create timer\n");
			mutex_unlock(&list_mutex);
			return ret;
		}
	}

	mutex_unlock(&list_mutex);
	return 0;
}

static void idletimer_tg_destroy(const struct xt_tgdtor_param *par)
{
	const struct idletimer_tg_info *info = par->targinfo;

	pr_debug("destroy targinfo %s\n", info->label);

	mutex_lock(&list_mutex);

	if (--info->timer->refcnt == 0) {
		pr_debug("deleting timer %s\n", info->label);

		list_del(&info->timer->entry);
		del_timer_sync(&info->timer->timer);
		cancel_work_sync(&info->timer->work);
		sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr);
		kfree(info->timer->attr.attr.name);
		kfree(info->timer);
	} else {
		pr_debug("decreased refcnt of timer %s to %u\n",
			 info->label, info->timer->refcnt);
	}

	mutex_unlock(&list_mutex);
}

static void idletimer_tg_destroy_v1(const struct xt_tgdtor_param *par)
{
	const struct idletimer_tg_info_v1 *info = par->targinfo;

	pr_debug("destroy targinfo %s\n", info->label);

	mutex_lock(&list_mutex);

	if (--info->timer->refcnt == 0) {
		pr_debug("deleting timer %s\n", info->label);

		list_del(&info->timer->entry);
		if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
			alarm_cancel(&info->timer->alarm);
		} else {
			del_timer_sync(&info->timer->timer);
		}
		cancel_work_sync(&info->timer->work);
		sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr);
		kfree(info->timer->attr.attr.name);
		kfree(info->timer);
	} else {
		pr_debug("decreased refcnt of timer %s to %u\n",
			 info->label, info->timer->refcnt);
	}

	mutex_unlock(&list_mutex);
}


static struct xt_target idletimer_tg[] __read_mostly = {
	{
	.name		= "IDLETIMER",
	.family		= NFPROTO_UNSPEC,
	.target		= idletimer_tg_target,
	.targetsize     = sizeof(struct idletimer_tg_info),
	.usersize	= offsetof(struct idletimer_tg_info, timer),
	.checkentry	= idletimer_tg_checkentry,
	.destroy        = idletimer_tg_destroy,
	.me		= THIS_MODULE,
	},
	{
	.name		= "IDLETIMER",
	.family		= NFPROTO_UNSPEC,
	.revision	= 1,
	.target		= idletimer_tg_target_v1,
	.targetsize     = sizeof(struct idletimer_tg_info_v1),
	.usersize	= offsetof(struct idletimer_tg_info_v1, timer),
	.checkentry	= idletimer_tg_checkentry_v1,
	.destroy        = idletimer_tg_destroy_v1,
	.me		= THIS_MODULE,
	},


};

static struct class *idletimer_tg_class;

static struct device *idletimer_tg_device;

static int __init idletimer_tg_init(void)
{
	int err;

	idletimer_tg_class = class_create(THIS_MODULE, "xt_idletimer");
	err = PTR_ERR(idletimer_tg_class);
	if (IS_ERR(idletimer_tg_class)) {
		pr_debug("couldn't register device class\n");
		goto out;
	}

	idletimer_tg_device = device_create(idletimer_tg_class, NULL,
					    MKDEV(0, 0), NULL, "timers");
	err = PTR_ERR(idletimer_tg_device);
	if (IS_ERR(idletimer_tg_device)) {
		pr_debug("couldn't register system device\n");
		goto out_class;
	}

	idletimer_tg_kobj = &idletimer_tg_device->kobj;

	err = xt_register_targets(idletimer_tg, ARRAY_SIZE(idletimer_tg));

	if (err < 0) {
		pr_debug("couldn't register xt target\n");
		goto out_dev;
	}

	return 0;
out_dev:
	device_destroy(idletimer_tg_class, MKDEV(0, 0));
out_class:
	class_destroy(idletimer_tg_class);
out:
	return err;
}

static void __exit idletimer_tg_exit(void)
{
	xt_unregister_targets(idletimer_tg, ARRAY_SIZE(idletimer_tg));

	device_destroy(idletimer_tg_class, MKDEV(0, 0));
	class_destroy(idletimer_tg_class);
}

module_init(idletimer_tg_init);
module_exit(idletimer_tg_exit);

MODULE_AUTHOR("Timo Teras <ext-timo.teras@nokia.com>");
MODULE_AUTHOR("Luciano Coelho <luciano.coelho@nokia.com>");
MODULE_DESCRIPTION("Xtables: idle time monitor");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("ipt_IDLETIMER");
MODULE_ALIAS("ip6t_IDLETIMER");