Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/net/netfilter/xt_IDLETIMER.c
4 *
5 * Netfilter module to trigger a timer when packet matches.
6 * After timer expires a kevent will be sent.
7 *
8 * Copyright (C) 2004, 2010 Nokia Corporation
9 * Written by Timo Teras <ext-timo.teras@nokia.com>
10 *
11 * Converted to x_tables and reworked for upstream inclusion
12 * by Luciano Coelho <luciano.coelho@nokia.com>
13 *
14 * Contact: Luciano Coelho <luciano.coelho@nokia.com>
15 */
16
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 sysfs_emit(buf, "%ld\n", time_diff);
89
90 return sysfs_emit(buf, "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 = timer_container_of(timer, t, timer);
104
105 pr_debug("timer %s expired\n", timer->attr.attr.name);
106
107 schedule_work(&timer->work);
108}
109
110static void idletimer_tg_alarmproc(struct alarm *alarm, ktime_t now)
111{
112 struct idletimer_tg *timer = alarm->data;
113
114 pr_debug("alarm %s expired\n", timer->attr.attr.name);
115 schedule_work(&timer->work);
116}
117
118static int idletimer_check_sysfs_name(const char *name, unsigned int size)
119{
120 int ret;
121
122 ret = xt_check_proc_name(name, size);
123 if (ret < 0)
124 return ret;
125
126 if (!strcmp(name, "power") ||
127 !strcmp(name, "subsystem") ||
128 !strcmp(name, "uevent"))
129 return -EINVAL;
130
131 return 0;
132}
133
134static int idletimer_tg_create(struct idletimer_tg_info *info)
135{
136 int ret;
137
138 info->timer = kzalloc_obj(*info->timer);
139 if (!info->timer) {
140 ret = -ENOMEM;
141 goto out;
142 }
143
144 ret = idletimer_check_sysfs_name(info->label, sizeof(info->label));
145 if (ret < 0)
146 goto out_free_timer;
147
148 sysfs_attr_init(&info->timer->attr.attr);
149 info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL);
150 if (!info->timer->attr.attr.name) {
151 ret = -ENOMEM;
152 goto out_free_timer;
153 }
154 info->timer->attr.attr.mode = 0444;
155 info->timer->attr.show = idletimer_tg_show;
156
157 ret = sysfs_create_file(idletimer_tg_kobj, &info->timer->attr.attr);
158 if (ret < 0) {
159 pr_debug("couldn't add file to sysfs");
160 goto out_free_attr;
161 }
162
163 list_add(&info->timer->entry, &idletimer_tg_list);
164
165 timer_setup(&info->timer->timer, idletimer_tg_expired, 0);
166 info->timer->refcnt = 1;
167
168 INIT_WORK(&info->timer->work, idletimer_tg_work);
169
170 mod_timer(&info->timer->timer,
171 secs_to_jiffies(info->timeout) + jiffies);
172
173 return 0;
174
175out_free_attr:
176 kfree(info->timer->attr.attr.name);
177out_free_timer:
178 kfree(info->timer);
179out:
180 return ret;
181}
182
183static int idletimer_tg_create_v1(struct idletimer_tg_info_v1 *info)
184{
185 int ret;
186
187 info->timer = kmalloc_obj(*info->timer);
188 if (!info->timer) {
189 ret = -ENOMEM;
190 goto out;
191 }
192
193 ret = idletimer_check_sysfs_name(info->label, sizeof(info->label));
194 if (ret < 0)
195 goto out_free_timer;
196
197 sysfs_attr_init(&info->timer->attr.attr);
198 info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL);
199 if (!info->timer->attr.attr.name) {
200 ret = -ENOMEM;
201 goto out_free_timer;
202 }
203 info->timer->attr.attr.mode = 0444;
204 info->timer->attr.show = idletimer_tg_show;
205
206 ret = sysfs_create_file(idletimer_tg_kobj, &info->timer->attr.attr);
207 if (ret < 0) {
208 pr_debug("couldn't add file to sysfs");
209 goto out_free_attr;
210 }
211
212 /* notify userspace */
213 kobject_uevent(idletimer_tg_kobj,KOBJ_ADD);
214
215 list_add(&info->timer->entry, &idletimer_tg_list);
216 pr_debug("timer type value is %u", info->timer_type);
217 info->timer->timer_type = info->timer_type;
218 info->timer->refcnt = 1;
219
220 INIT_WORK(&info->timer->work, idletimer_tg_work);
221
222 if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
223 ktime_t tout;
224 alarm_init(&info->timer->alarm, ALARM_BOOTTIME,
225 idletimer_tg_alarmproc);
226 info->timer->alarm.data = info->timer;
227 tout = ktime_set(info->timeout, 0);
228 alarm_start_relative(&info->timer->alarm, tout);
229 } else {
230 timer_setup(&info->timer->timer, idletimer_tg_expired, 0);
231 mod_timer(&info->timer->timer,
232 secs_to_jiffies(info->timeout) + jiffies);
233 }
234
235 return 0;
236
237out_free_attr:
238 kfree(info->timer->attr.attr.name);
239out_free_timer:
240 kfree(info->timer);
241out:
242 return ret;
243}
244
245/*
246 * The actual xt_tables plugin.
247 */
248static unsigned int idletimer_tg_target(struct sk_buff *skb,
249 const struct xt_action_param *par)
250{
251 const struct idletimer_tg_info *info = par->targinfo;
252
253 pr_debug("resetting timer %s, timeout period %u\n",
254 info->label, info->timeout);
255
256 mod_timer(&info->timer->timer,
257 secs_to_jiffies(info->timeout) + jiffies);
258
259 return XT_CONTINUE;
260}
261
262/*
263 * The actual xt_tables plugin.
264 */
265static unsigned int idletimer_tg_target_v1(struct sk_buff *skb,
266 const struct xt_action_param *par)
267{
268 const struct idletimer_tg_info_v1 *info = par->targinfo;
269
270 pr_debug("resetting timer %s, timeout period %u\n",
271 info->label, info->timeout);
272
273 if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
274 ktime_t tout = ktime_set(info->timeout, 0);
275 alarm_start_relative(&info->timer->alarm, tout);
276 } else {
277 mod_timer(&info->timer->timer,
278 secs_to_jiffies(info->timeout) + jiffies);
279 }
280
281 return XT_CONTINUE;
282}
283
284static int idletimer_tg_helper(struct idletimer_tg_info *info)
285{
286 if (info->timeout == 0) {
287 pr_debug("timeout value is zero\n");
288 return -EINVAL;
289 }
290 if (info->timeout >= INT_MAX / 1000) {
291 pr_debug("timeout value is too big\n");
292 return -EINVAL;
293 }
294 if (info->label[0] == '\0' ||
295 strnlen(info->label,
296 MAX_IDLETIMER_LABEL_SIZE) == MAX_IDLETIMER_LABEL_SIZE) {
297 pr_debug("label is empty or not nul-terminated\n");
298 return -EINVAL;
299 }
300 return 0;
301}
302
303
304static int idletimer_tg_checkentry(const struct xt_tgchk_param *par)
305{
306 struct idletimer_tg_info *info = par->targinfo;
307 int ret;
308
309 pr_debug("checkentry targinfo%s\n", info->label);
310
311 ret = idletimer_tg_helper(info);
312 if(ret < 0)
313 {
314 pr_debug("checkentry helper return invalid\n");
315 return -EINVAL;
316 }
317 mutex_lock(&list_mutex);
318
319 info->timer = __idletimer_tg_find_by_label(info->label);
320 if (info->timer) {
321 if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
322 pr_debug("Adding/Replacing rule with same label and different timer type is not allowed\n");
323 mutex_unlock(&list_mutex);
324 return -EINVAL;
325 }
326
327 info->timer->refcnt++;
328 mod_timer(&info->timer->timer,
329 secs_to_jiffies(info->timeout) + jiffies);
330
331 pr_debug("increased refcnt of timer %s to %u\n",
332 info->label, info->timer->refcnt);
333 } else {
334 ret = idletimer_tg_create(info);
335 if (ret < 0) {
336 pr_debug("failed to create timer\n");
337 mutex_unlock(&list_mutex);
338 return ret;
339 }
340 }
341
342 mutex_unlock(&list_mutex);
343 return 0;
344}
345
346static int idletimer_tg_checkentry_v1(const struct xt_tgchk_param *par)
347{
348 struct idletimer_tg_info_v1 *info = par->targinfo;
349 int ret;
350
351 pr_debug("checkentry targinfo%s\n", info->label);
352
353 if (info->send_nl_msg)
354 return -EOPNOTSUPP;
355
356 ret = idletimer_tg_helper((struct idletimer_tg_info *)info);
357 if(ret < 0)
358 {
359 pr_debug("checkentry helper return invalid\n");
360 return -EINVAL;
361 }
362
363 if (info->timer_type > XT_IDLETIMER_ALARM) {
364 pr_debug("invalid value for timer type\n");
365 return -EINVAL;
366 }
367
368 mutex_lock(&list_mutex);
369
370 info->timer = __idletimer_tg_find_by_label(info->label);
371 if (info->timer) {
372 if (info->timer->timer_type != info->timer_type) {
373 pr_debug("Adding/Replacing rule with same label and different timer type is not allowed\n");
374 mutex_unlock(&list_mutex);
375 return -EINVAL;
376 }
377
378 info->timer->refcnt++;
379 if (info->timer_type & XT_IDLETIMER_ALARM) {
380 /* calculate remaining expiry time */
381 ktime_t tout = alarm_expires_remaining(&info->timer->alarm);
382 struct timespec64 ktimespec = ktime_to_timespec64(tout);
383
384 if (ktimespec.tv_sec > 0) {
385 pr_debug("time_expiry_remaining %lld\n",
386 ktimespec.tv_sec);
387 alarm_start_relative(&info->timer->alarm, tout);
388 }
389 } else {
390 mod_timer(&info->timer->timer,
391 secs_to_jiffies(info->timeout) + jiffies);
392 }
393 pr_debug("increased refcnt of timer %s to %u\n",
394 info->label, info->timer->refcnt);
395 } else {
396 ret = idletimer_tg_create_v1(info);
397 if (ret < 0) {
398 pr_debug("failed to create timer\n");
399 mutex_unlock(&list_mutex);
400 return ret;
401 }
402 }
403
404 mutex_unlock(&list_mutex);
405 return 0;
406}
407
408static void idletimer_tg_destroy(const struct xt_tgdtor_param *par)
409{
410 const struct idletimer_tg_info *info = par->targinfo;
411
412 pr_debug("destroy targinfo %s\n", info->label);
413
414 mutex_lock(&list_mutex);
415
416 if (--info->timer->refcnt > 0) {
417 pr_debug("decreased refcnt of timer %s to %u\n",
418 info->label, info->timer->refcnt);
419 mutex_unlock(&list_mutex);
420 return;
421 }
422
423 pr_debug("deleting timer %s\n", info->label);
424
425 list_del(&info->timer->entry);
426 mutex_unlock(&list_mutex);
427
428 timer_shutdown_sync(&info->timer->timer);
429 cancel_work_sync(&info->timer->work);
430 sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr);
431 kfree(info->timer->attr.attr.name);
432 kfree(info->timer);
433}
434
435static void idletimer_tg_destroy_v1(const struct xt_tgdtor_param *par)
436{
437 const struct idletimer_tg_info_v1 *info = par->targinfo;
438
439 pr_debug("destroy targinfo %s\n", info->label);
440
441 mutex_lock(&list_mutex);
442
443 if (--info->timer->refcnt > 0) {
444 pr_debug("decreased refcnt of timer %s to %u\n",
445 info->label, info->timer->refcnt);
446 mutex_unlock(&list_mutex);
447 return;
448 }
449
450 pr_debug("deleting timer %s\n", info->label);
451
452 list_del(&info->timer->entry);
453 mutex_unlock(&list_mutex);
454
455 if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
456 alarm_cancel(&info->timer->alarm);
457 } else {
458 timer_shutdown_sync(&info->timer->timer);
459 }
460 cancel_work_sync(&info->timer->work);
461 sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr);
462 kfree(info->timer->attr.attr.name);
463 kfree(info->timer);
464}
465
466
467static struct xt_target idletimer_tg[] __read_mostly = {
468 {
469 .name = "IDLETIMER",
470 .family = NFPROTO_IPV4,
471 .target = idletimer_tg_target,
472 .targetsize = sizeof(struct idletimer_tg_info),
473 .usersize = offsetof(struct idletimer_tg_info, timer),
474 .checkentry = idletimer_tg_checkentry,
475 .destroy = idletimer_tg_destroy,
476 .me = THIS_MODULE,
477 },
478 {
479 .name = "IDLETIMER",
480 .family = NFPROTO_IPV4,
481 .revision = 1,
482 .target = idletimer_tg_target_v1,
483 .targetsize = sizeof(struct idletimer_tg_info_v1),
484 .usersize = offsetof(struct idletimer_tg_info_v1, timer),
485 .checkentry = idletimer_tg_checkentry_v1,
486 .destroy = idletimer_tg_destroy_v1,
487 .me = THIS_MODULE,
488 },
489#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
490 {
491 .name = "IDLETIMER",
492 .family = NFPROTO_IPV6,
493 .target = idletimer_tg_target,
494 .targetsize = sizeof(struct idletimer_tg_info),
495 .usersize = offsetof(struct idletimer_tg_info, timer),
496 .checkentry = idletimer_tg_checkentry,
497 .destroy = idletimer_tg_destroy,
498 .me = THIS_MODULE,
499 },
500 {
501 .name = "IDLETIMER",
502 .family = NFPROTO_IPV6,
503 .revision = 1,
504 .target = idletimer_tg_target_v1,
505 .targetsize = sizeof(struct idletimer_tg_info_v1),
506 .usersize = offsetof(struct idletimer_tg_info_v1, timer),
507 .checkentry = idletimer_tg_checkentry_v1,
508 .destroy = idletimer_tg_destroy_v1,
509 .me = THIS_MODULE,
510 },
511#endif
512};
513
514static struct class *idletimer_tg_class;
515
516static struct device *idletimer_tg_device;
517
518static int __init idletimer_tg_init(void)
519{
520 int err;
521
522 idletimer_tg_class = class_create("xt_idletimer");
523 err = PTR_ERR(idletimer_tg_class);
524 if (IS_ERR(idletimer_tg_class)) {
525 pr_debug("couldn't register device class\n");
526 goto out;
527 }
528
529 idletimer_tg_device = device_create(idletimer_tg_class, NULL,
530 MKDEV(0, 0), NULL, "timers");
531 err = PTR_ERR(idletimer_tg_device);
532 if (IS_ERR(idletimer_tg_device)) {
533 pr_debug("couldn't register system device\n");
534 goto out_class;
535 }
536
537 idletimer_tg_kobj = &idletimer_tg_device->kobj;
538
539 err = xt_register_targets(idletimer_tg, ARRAY_SIZE(idletimer_tg));
540
541 if (err < 0) {
542 pr_debug("couldn't register xt target\n");
543 goto out_dev;
544 }
545
546 return 0;
547out_dev:
548 device_destroy(idletimer_tg_class, MKDEV(0, 0));
549out_class:
550 class_destroy(idletimer_tg_class);
551out:
552 return err;
553}
554
555static void __exit idletimer_tg_exit(void)
556{
557 xt_unregister_targets(idletimer_tg, ARRAY_SIZE(idletimer_tg));
558
559 device_destroy(idletimer_tg_class, MKDEV(0, 0));
560 class_destroy(idletimer_tg_class);
561}
562
563module_init(idletimer_tg_init);
564module_exit(idletimer_tg_exit);
565
566MODULE_AUTHOR("Timo Teras <ext-timo.teras@nokia.com>");
567MODULE_AUTHOR("Luciano Coelho <luciano.coelho@nokia.com>");
568MODULE_DESCRIPTION("Xtables: idle time monitor");
569MODULE_LICENSE("GPL v2");
570MODULE_ALIAS("ipt_IDLETIMER");
571MODULE_ALIAS("ip6t_IDLETIMER");