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
8 * Written by Timo Teras <ext-timo.teras@nokia.com>
10 * Converted to x_tables and reworked for upstream inclusion
11 * by Luciano Coelho <luciano.coelho@nokia.com>
13 * Contact: Luciano Coelho <luciano.coelho@nokia.com>
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License
17 * version 2 as published by the Free Software Foundation.
19 * This program is distributed in the hope that it will be useful, but
20 * WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 * General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, write to the Free Software
26 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
30 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32 #include <linux/module.h>
33 #include <linux/timer.h>
34 #include <linux/list.h>
35 #include <linux/mutex.h>
36 #include <linux/netfilter.h>
37 #include <linux/netfilter/x_tables.h>
38 #include <linux/netfilter/xt_IDLETIMER.h>
39 #include <linux/kdev_t.h>
40 #include <linux/kobject.h>
41 #include <linux/workqueue.h>
42 #include <linux/sysfs.h>
45 struct list_head entry;
46 struct timer_list timer;
47 struct work_struct work;
50 struct device_attribute attr;
55 static LIST_HEAD(idletimer_tg_list);
56 static DEFINE_MUTEX(list_mutex);
58 static struct kobject *idletimer_tg_kobj;
61 struct idletimer_tg *__idletimer_tg_find_by_label(const char *label)
63 struct idletimer_tg *entry;
65 list_for_each_entry(entry, &idletimer_tg_list, entry) {
66 if (!strcmp(label, entry->attr.attr.name))
73 static ssize_t idletimer_tg_show(struct device *dev,
74 struct device_attribute *attr, char *buf)
76 struct idletimer_tg *timer;
77 unsigned long expires = 0;
79 mutex_lock(&list_mutex);
81 timer = __idletimer_tg_find_by_label(attr->attr.name);
83 expires = timer->timer.expires;
85 mutex_unlock(&list_mutex);
87 if (time_after(expires, jiffies))
88 return sprintf(buf, "%u\n",
89 jiffies_to_msecs(expires - jiffies) / 1000);
91 return sprintf(buf, "0\n");
94 static void idletimer_tg_work(struct work_struct *work)
96 struct idletimer_tg *timer = container_of(work, struct idletimer_tg,
99 sysfs_notify(idletimer_tg_kobj, NULL, timer->attr.attr.name);
102 static void idletimer_tg_expired(struct timer_list *t)
104 struct idletimer_tg *timer = from_timer(timer, t, timer);
106 pr_debug("timer %s expired\n", timer->attr.attr.name);
108 schedule_work(&timer->work);
111 static int idletimer_check_sysfs_name(const char *name, unsigned int size)
115 ret = xt_check_proc_name(name, size);
119 if (!strcmp(name, "power") ||
120 !strcmp(name, "subsystem") ||
121 !strcmp(name, "uevent"))
127 static int idletimer_tg_create(struct idletimer_tg_info *info)
131 info->timer = kmalloc(sizeof(*info->timer), GFP_KERNEL);
137 ret = idletimer_check_sysfs_name(info->label, sizeof(info->label));
141 sysfs_attr_init(&info->timer->attr.attr);
142 info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL);
143 if (!info->timer->attr.attr.name) {
147 info->timer->attr.attr.mode = 0444;
148 info->timer->attr.show = idletimer_tg_show;
150 ret = sysfs_create_file(idletimer_tg_kobj, &info->timer->attr.attr);
152 pr_debug("couldn't add file to sysfs");
156 list_add(&info->timer->entry, &idletimer_tg_list);
158 timer_setup(&info->timer->timer, idletimer_tg_expired, 0);
159 info->timer->refcnt = 1;
161 INIT_WORK(&info->timer->work, idletimer_tg_work);
163 mod_timer(&info->timer->timer,
164 msecs_to_jiffies(info->timeout * 1000) + jiffies);
169 kfree(info->timer->attr.attr.name);
177 * The actual xt_tables plugin.
179 static unsigned int idletimer_tg_target(struct sk_buff *skb,
180 const struct xt_action_param *par)
182 const struct idletimer_tg_info *info = par->targinfo;
184 pr_debug("resetting timer %s, timeout period %u\n",
185 info->label, info->timeout);
187 mod_timer(&info->timer->timer,
188 msecs_to_jiffies(info->timeout * 1000) + jiffies);
193 static int idletimer_tg_checkentry(const struct xt_tgchk_param *par)
195 struct idletimer_tg_info *info = par->targinfo;
198 pr_debug("checkentry targinfo%s\n", info->label);
200 if (info->timeout == 0) {
201 pr_debug("timeout value is zero\n");
204 if (info->timeout >= INT_MAX / 1000) {
205 pr_debug("timeout value is too big\n");
208 if (info->label[0] == '\0' ||
210 MAX_IDLETIMER_LABEL_SIZE) == MAX_IDLETIMER_LABEL_SIZE) {
211 pr_debug("label is empty or not nul-terminated\n");
215 mutex_lock(&list_mutex);
217 info->timer = __idletimer_tg_find_by_label(info->label);
219 info->timer->refcnt++;
220 mod_timer(&info->timer->timer,
221 msecs_to_jiffies(info->timeout * 1000) + jiffies);
223 pr_debug("increased refcnt of timer %s to %u\n",
224 info->label, info->timer->refcnt);
226 ret = idletimer_tg_create(info);
228 pr_debug("failed to create timer\n");
229 mutex_unlock(&list_mutex);
234 mutex_unlock(&list_mutex);
238 static void idletimer_tg_destroy(const struct xt_tgdtor_param *par)
240 const struct idletimer_tg_info *info = par->targinfo;
242 pr_debug("destroy targinfo %s\n", info->label);
244 mutex_lock(&list_mutex);
246 if (--info->timer->refcnt == 0) {
247 pr_debug("deleting timer %s\n", info->label);
249 list_del(&info->timer->entry);
250 del_timer_sync(&info->timer->timer);
251 cancel_work_sync(&info->timer->work);
252 sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr);
253 kfree(info->timer->attr.attr.name);
256 pr_debug("decreased refcnt of timer %s to %u\n",
257 info->label, info->timer->refcnt);
260 mutex_unlock(&list_mutex);
263 static struct xt_target idletimer_tg __read_mostly = {
265 .family = NFPROTO_UNSPEC,
266 .target = idletimer_tg_target,
267 .targetsize = sizeof(struct idletimer_tg_info),
268 .usersize = offsetof(struct idletimer_tg_info, timer),
269 .checkentry = idletimer_tg_checkentry,
270 .destroy = idletimer_tg_destroy,
274 static struct class *idletimer_tg_class;
276 static struct device *idletimer_tg_device;
278 static int __init idletimer_tg_init(void)
282 idletimer_tg_class = class_create(THIS_MODULE, "xt_idletimer");
283 err = PTR_ERR(idletimer_tg_class);
284 if (IS_ERR(idletimer_tg_class)) {
285 pr_debug("couldn't register device class\n");
289 idletimer_tg_device = device_create(idletimer_tg_class, NULL,
290 MKDEV(0, 0), NULL, "timers");
291 err = PTR_ERR(idletimer_tg_device);
292 if (IS_ERR(idletimer_tg_device)) {
293 pr_debug("couldn't register system device\n");
297 idletimer_tg_kobj = &idletimer_tg_device->kobj;
299 err = xt_register_target(&idletimer_tg);
301 pr_debug("couldn't register xt target\n");
307 device_destroy(idletimer_tg_class, MKDEV(0, 0));
309 class_destroy(idletimer_tg_class);
314 static void __exit idletimer_tg_exit(void)
316 xt_unregister_target(&idletimer_tg);
318 device_destroy(idletimer_tg_class, MKDEV(0, 0));
319 class_destroy(idletimer_tg_class);
322 module_init(idletimer_tg_init);
323 module_exit(idletimer_tg_exit);
325 MODULE_AUTHOR("Timo Teras <ext-timo.teras@nokia.com>");
326 MODULE_AUTHOR("Luciano Coelho <luciano.coelho@nokia.com>");
327 MODULE_DESCRIPTION("Xtables: idle time monitor");
328 MODULE_LICENSE("GPL v2");
329 MODULE_ALIAS("ipt_IDLETIMER");
330 MODULE_ALIAS("ip6t_IDLETIMER");