2 * linux/net/netfilter/xt_IDLETIMER.c
4 * Netfilter module to trigger a timer when packet matches.
5 * After timer expires a kevent will be sent.
7 * Copyright (C) 2004, 2010 Nokia Corporation
9 * Written by Timo Teras <ext-timo.teras@nokia.com>
11 * Converted to x_tables and reworked for upstream inclusion
12 * by Luciano Coelho <luciano.coelho@nokia.com>
14 * Contact: Luciano Coelho <luciano.coelho@nokia.com>
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License
18 * version 2 as published by the Free Software Foundation.
20 * This program is distributed in the hope that it will be useful, but
21 * WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 * General Public License for more details.
25 * You should have received a copy of the GNU General Public License
26 * along with this program; if not, write to the Free Software
27 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33 #include <linux/module.h>
34 #include <linux/timer.h>
35 #include <linux/list.h>
36 #include <linux/mutex.h>
37 #include <linux/netfilter.h>
38 #include <linux/netfilter/x_tables.h>
39 #include <linux/netfilter/xt_IDLETIMER.h>
40 #include <linux/kdev_t.h>
41 #include <linux/kobject.h>
42 #include <linux/skbuff.h>
43 #include <linux/workqueue.h>
44 #include <linux/sysfs.h>
45 #include <linux/rtc.h>
46 #include <linux/time.h>
47 #include <linux/math64.h>
48 #include <linux/suspend.h>
49 #include <linux/notifier.h>
50 #include <net/net_namespace.h>
52 struct idletimer_tg_attr
{
53 struct attribute attr
;
54 ssize_t (*show
)(struct kobject
*kobj
,
55 struct attribute
*attr
, char *buf
);
59 struct list_head entry
;
60 struct timer_list timer
;
61 struct work_struct work
;
64 struct idletimer_tg_attr attr
;
66 struct timespec delayed_timer_trigger
;
67 struct timespec last_modified_timer
;
68 struct timespec last_suspend_time
;
69 struct notifier_block pm_nb
;
78 static LIST_HEAD(idletimer_tg_list
);
79 static DEFINE_MUTEX(list_mutex
);
80 static DEFINE_SPINLOCK(timestamp_lock
);
82 static struct kobject
*idletimer_tg_kobj
;
84 static bool check_for_delayed_trigger(struct idletimer_tg
*timer
,
89 spin_lock_bh(×tamp_lock
);
90 timer
->work_pending
= false;
91 if ((ts
->tv_sec
- timer
->last_modified_timer
.tv_sec
) > timer
->timeout
||
92 timer
->delayed_timer_trigger
.tv_sec
!= 0) {
94 temp
.tv_sec
= timer
->timeout
;
96 if (timer
->delayed_timer_trigger
.tv_sec
!= 0) {
97 temp
= timespec_add(timer
->delayed_timer_trigger
, temp
);
98 ts
->tv_sec
= temp
.tv_sec
;
99 ts
->tv_nsec
= temp
.tv_nsec
;
100 timer
->delayed_timer_trigger
.tv_sec
= 0;
101 timer
->work_pending
= true;
102 schedule_work(&timer
->work
);
104 temp
= timespec_add(timer
->last_modified_timer
, temp
);
105 ts
->tv_sec
= temp
.tv_sec
;
106 ts
->tv_nsec
= temp
.tv_nsec
;
109 state
= timer
->active
;
111 spin_unlock_bh(×tamp_lock
);
115 static void notify_netlink_uevent(const char *iface
, struct idletimer_tg
*timer
)
117 char iface_msg
[NLMSG_MAX_SIZE
];
118 char state_msg
[NLMSG_MAX_SIZE
];
119 char timestamp_msg
[NLMSG_MAX_SIZE
];
120 char *envp
[] = { iface_msg
, state_msg
, timestamp_msg
, NULL
};
126 res
= snprintf(iface_msg
, NLMSG_MAX_SIZE
, "INTERFACE=%s",
128 if (NLMSG_MAX_SIZE
<= res
) {
129 pr_err("message too long (%d)", res
);
133 get_monotonic_boottime(&ts
);
134 state
= check_for_delayed_trigger(timer
, &ts
);
135 res
= snprintf(state_msg
, NLMSG_MAX_SIZE
, "STATE=%s",
136 state
? "active" : "inactive");
138 if (NLMSG_MAX_SIZE
<= res
) {
139 pr_err("message too long (%d)", res
);
143 time_ns
= timespec_to_ns(&ts
);
144 res
= snprintf(timestamp_msg
, NLMSG_MAX_SIZE
, "TIME_NS=%llu", time_ns
);
145 if (NLMSG_MAX_SIZE
<= res
) {
146 timestamp_msg
[0] = '\0';
147 pr_err("message too long (%d)", res
);
150 pr_debug("putting nlmsg: <%s> <%s>\n", iface_msg
, state_msg
);
151 kobject_uevent_env(idletimer_tg_kobj
, KOBJ_CHANGE
, envp
);
158 struct idletimer_tg
*__idletimer_tg_find_by_label(const char *label
)
160 struct idletimer_tg
*entry
;
164 list_for_each_entry(entry
, &idletimer_tg_list
, entry
) {
165 if (!strcmp(label
, entry
->attr
.attr
.name
))
172 static ssize_t
idletimer_tg_show(struct kobject
*kobj
, struct attribute
*attr
,
175 struct idletimer_tg
*timer
;
176 unsigned long expires
= 0;
177 unsigned long now
= jiffies
;
179 mutex_lock(&list_mutex
);
181 timer
= __idletimer_tg_find_by_label(attr
->name
);
183 expires
= timer
->timer
.expires
;
185 mutex_unlock(&list_mutex
);
187 if (time_after(expires
, now
))
188 return sprintf(buf
, "%u\n",
189 jiffies_to_msecs(expires
- now
) / 1000);
191 if (timer
->send_nl_msg
)
192 return sprintf(buf
, "0 %d\n",
193 jiffies_to_msecs(now
- expires
) / 1000);
195 return sprintf(buf
, "0\n");
198 static void idletimer_tg_work(struct work_struct
*work
)
200 struct idletimer_tg
*timer
= container_of(work
, struct idletimer_tg
,
203 sysfs_notify(idletimer_tg_kobj
, NULL
, timer
->attr
.attr
.name
);
205 if (timer
->send_nl_msg
)
206 notify_netlink_uevent(timer
->attr
.attr
.name
, timer
);
209 static void idletimer_tg_expired(unsigned long data
)
211 struct idletimer_tg
*timer
= (struct idletimer_tg
*) data
;
213 pr_debug("timer %s expired\n", timer
->attr
.attr
.name
);
214 spin_lock_bh(×tamp_lock
);
215 timer
->active
= false;
216 timer
->work_pending
= true;
217 schedule_work(&timer
->work
);
218 spin_unlock_bh(×tamp_lock
);
221 static int idletimer_resume(struct notifier_block
*notifier
,
222 unsigned long pm_event
, void *unused
)
225 unsigned long time_diff
, now
= jiffies
;
226 struct idletimer_tg
*timer
= container_of(notifier
,
227 struct idletimer_tg
, pm_nb
);
231 case PM_SUSPEND_PREPARE
:
232 get_monotonic_boottime(&timer
->last_suspend_time
);
234 case PM_POST_SUSPEND
:
235 spin_lock_bh(×tamp_lock
);
236 if (!timer
->active
) {
237 spin_unlock_bh(×tamp_lock
);
240 /* since jiffies are not updated when suspended now represents
241 * the time it would have suspended */
242 if (time_after(timer
->timer
.expires
, now
)) {
243 get_monotonic_boottime(&ts
);
244 ts
= timespec_sub(ts
, timer
->last_suspend_time
);
245 time_diff
= timespec_to_jiffies(&ts
);
246 if (timer
->timer
.expires
> (time_diff
+ now
)) {
247 mod_timer_pending(&timer
->timer
,
248 (timer
->timer
.expires
- time_diff
));
250 del_timer(&timer
->timer
);
251 timer
->timer
.expires
= 0;
252 timer
->active
= false;
253 timer
->work_pending
= true;
254 schedule_work(&timer
->work
);
257 spin_unlock_bh(×tamp_lock
);
265 static int idletimer_tg_create(struct idletimer_tg_info
*info
)
269 info
->timer
= kmalloc(sizeof(*info
->timer
), GFP_KERNEL
);
275 info
->timer
->attr
.attr
.name
= kstrdup(info
->label
, GFP_KERNEL
);
276 if (!info
->timer
->attr
.attr
.name
) {
280 info
->timer
->attr
.attr
.mode
= S_IRUGO
;
281 info
->timer
->attr
.show
= idletimer_tg_show
;
283 ret
= sysfs_create_file(idletimer_tg_kobj
, &info
->timer
->attr
.attr
);
285 pr_debug("couldn't add file to sysfs");
289 list_add(&info
->timer
->entry
, &idletimer_tg_list
);
291 setup_timer(&info
->timer
->timer
, idletimer_tg_expired
,
292 (unsigned long) info
->timer
);
293 info
->timer
->refcnt
= 1;
294 info
->timer
->send_nl_msg
= (info
->send_nl_msg
== 0) ? false : true;
295 info
->timer
->active
= true;
296 info
->timer
->timeout
= info
->timeout
;
298 info
->timer
->delayed_timer_trigger
.tv_sec
= 0;
299 info
->timer
->delayed_timer_trigger
.tv_nsec
= 0;
300 info
->timer
->work_pending
= false;
301 get_monotonic_boottime(&info
->timer
->last_modified_timer
);
303 info
->timer
->pm_nb
.notifier_call
= idletimer_resume
;
304 ret
= register_pm_notifier(&info
->timer
->pm_nb
);
306 printk(KERN_WARNING
"[%s] Failed to register pm notifier %d\n",
309 mod_timer(&info
->timer
->timer
,
310 msecs_to_jiffies(info
->timeout
* 1000) + jiffies
);
312 INIT_WORK(&info
->timer
->work
, idletimer_tg_work
);
317 kfree(info
->timer
->attr
.attr
.name
);
324 static void reset_timer(const struct idletimer_tg_info
*info
)
326 unsigned long now
= jiffies
;
327 struct idletimer_tg
*timer
= info
->timer
;
330 spin_lock_bh(×tamp_lock
);
331 timer_prev
= timer
->active
;
332 timer
->active
= true;
333 /* timer_prev is used to guard overflow problem in time_before*/
334 if (!timer_prev
|| time_before(timer
->timer
.expires
, now
)) {
335 pr_debug("Starting Checkentry timer (Expired, Jiffies): %lu, %lu\n",
336 timer
->timer
.expires
, now
);
337 /* checks if there is a pending inactive notification*/
338 if (timer
->work_pending
)
339 timer
->delayed_timer_trigger
= timer
->last_modified_timer
;
341 timer
->work_pending
= true;
342 schedule_work(&timer
->work
);
346 get_monotonic_boottime(&timer
->last_modified_timer
);
347 mod_timer(&timer
->timer
,
348 msecs_to_jiffies(info
->timeout
* 1000) + now
);
349 spin_unlock_bh(×tamp_lock
);
353 * The actual xt_tables plugin.
355 static unsigned int idletimer_tg_target(struct sk_buff
*skb
,
356 const struct xt_action_param
*par
)
358 const struct idletimer_tg_info
*info
= par
->targinfo
;
359 unsigned long now
= jiffies
;
361 pr_debug("resetting timer %s, timeout period %u\n",
362 info
->label
, info
->timeout
);
364 BUG_ON(!info
->timer
);
366 info
->timer
->active
= true;
368 if (time_before(info
->timer
->timer
.expires
, now
)) {
369 schedule_work(&info
->timer
->work
);
370 pr_debug("Starting timer %s (Expired, Jiffies): %lu, %lu\n",
371 info
->label
, info
->timer
->timer
.expires
, now
);
374 /* TODO: Avoid modifying timers on each packet */
379 static int idletimer_tg_checkentry(const struct xt_tgchk_param
*par
)
381 struct idletimer_tg_info
*info
= par
->targinfo
;
384 pr_debug("checkentry targinfo %s\n", info
->label
);
386 if (info
->timeout
== 0) {
387 pr_debug("timeout value is zero\n");
391 if (info
->label
[0] == '\0' ||
393 MAX_IDLETIMER_LABEL_SIZE
) == MAX_IDLETIMER_LABEL_SIZE
) {
394 pr_debug("label is empty or not nul-terminated\n");
398 mutex_lock(&list_mutex
);
400 info
->timer
= __idletimer_tg_find_by_label(info
->label
);
402 info
->timer
->refcnt
++;
404 pr_debug("increased refcnt of timer %s to %u\n",
405 info
->label
, info
->timer
->refcnt
);
407 ret
= idletimer_tg_create(info
);
409 pr_debug("failed to create timer\n");
410 mutex_unlock(&list_mutex
);
415 mutex_unlock(&list_mutex
);
420 static void idletimer_tg_destroy(const struct xt_tgdtor_param
*par
)
422 const struct idletimer_tg_info
*info
= par
->targinfo
;
424 pr_debug("destroy targinfo %s\n", info
->label
);
426 mutex_lock(&list_mutex
);
428 if (--info
->timer
->refcnt
== 0) {
429 pr_debug("deleting timer %s\n", info
->label
);
431 list_del(&info
->timer
->entry
);
432 del_timer_sync(&info
->timer
->timer
);
433 sysfs_remove_file(idletimer_tg_kobj
, &info
->timer
->attr
.attr
);
434 unregister_pm_notifier(&info
->timer
->pm_nb
);
435 kfree(info
->timer
->attr
.attr
.name
);
438 pr_debug("decreased refcnt of timer %s to %u\n",
439 info
->label
, info
->timer
->refcnt
);
442 mutex_unlock(&list_mutex
);
445 static struct xt_target idletimer_tg __read_mostly
= {
448 .family
= NFPROTO_UNSPEC
,
449 .target
= idletimer_tg_target
,
450 .targetsize
= sizeof(struct idletimer_tg_info
),
451 .checkentry
= idletimer_tg_checkentry
,
452 .destroy
= idletimer_tg_destroy
,
456 static struct class *idletimer_tg_class
;
458 static struct device
*idletimer_tg_device
;
460 static int __init
idletimer_tg_init(void)
464 idletimer_tg_class
= class_create(THIS_MODULE
, "xt_idletimer");
465 err
= PTR_ERR(idletimer_tg_class
);
466 if (IS_ERR(idletimer_tg_class
)) {
467 pr_debug("couldn't register device class\n");
471 idletimer_tg_device
= device_create(idletimer_tg_class
, NULL
,
472 MKDEV(0, 0), NULL
, "timers");
473 err
= PTR_ERR(idletimer_tg_device
);
474 if (IS_ERR(idletimer_tg_device
)) {
475 pr_debug("couldn't register system device\n");
479 idletimer_tg_kobj
= &idletimer_tg_device
->kobj
;
481 err
= xt_register_target(&idletimer_tg
);
483 pr_debug("couldn't register xt target\n");
489 device_destroy(idletimer_tg_class
, MKDEV(0, 0));
491 class_destroy(idletimer_tg_class
);
496 static void __exit
idletimer_tg_exit(void)
498 xt_unregister_target(&idletimer_tg
);
500 device_destroy(idletimer_tg_class
, MKDEV(0, 0));
501 class_destroy(idletimer_tg_class
);
504 module_init(idletimer_tg_init
);
505 module_exit(idletimer_tg_exit
);
507 MODULE_AUTHOR("Timo Teras <ext-timo.teras@nokia.com>");
508 MODULE_AUTHOR("Luciano Coelho <luciano.coelho@nokia.com>");
509 MODULE_DESCRIPTION("Xtables: idle time monitor");
510 MODULE_LICENSE("GPL v2");
511 MODULE_ALIAS("ipt_IDLETIMER");
512 MODULE_ALIAS("ip6t_IDLETIMER");
513 MODULE_ALIAS("arpt_IDLETIMER");