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>
44 struct idletimer_tg_attr {
45 struct attribute attr;
46 ssize_t (*show)(struct kobject *kobj,
47 struct attribute *attr, char *buf);
51 struct list_head entry;
52 struct timer_list timer;
53 struct work_struct work;
56 struct idletimer_tg_attr attr;
61 static LIST_HEAD(idletimer_tg_list);
62 static DEFINE_MUTEX(list_mutex);
64 static struct kobject *idletimer_tg_kobj;
67 struct idletimer_tg *__idletimer_tg_find_by_label(const char *label)
69 struct idletimer_tg *entry;
73 list_for_each_entry(entry, &idletimer_tg_list, entry) {
74 if (!strcmp(label, entry->attr.attr.name))
81 static ssize_t idletimer_tg_show(struct kobject *kobj, struct attribute *attr,
84 struct idletimer_tg *timer;
85 unsigned long expires = 0;
87 mutex_lock(&list_mutex);
89 timer = __idletimer_tg_find_by_label(attr->name);
91 expires = timer->timer.expires;
93 mutex_unlock(&list_mutex);
95 if (time_after(expires, jiffies))
96 return sprintf(buf, "%u\n",
97 jiffies_to_msecs(expires - jiffies) / 1000);
99 return sprintf(buf, "0\n");
102 static void idletimer_tg_work(struct work_struct *work)
104 struct idletimer_tg *timer = container_of(work, struct idletimer_tg,
107 sysfs_notify(idletimer_tg_kobj, NULL, timer->attr.attr.name);
110 static void idletimer_tg_expired(unsigned long data)
112 struct idletimer_tg *timer = (struct idletimer_tg *) data;
114 pr_debug("timer %s expired\n", timer->attr.attr.name);
116 schedule_work(&timer->work);
119 static int idletimer_tg_create(struct idletimer_tg_info *info)
123 info->timer = kmalloc(sizeof(*info->timer), GFP_KERNEL);
129 sysfs_attr_init(&info->timer->attr.attr);
130 info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL);
131 if (!info->timer->attr.attr.name) {
135 info->timer->attr.attr.mode = S_IRUGO;
136 info->timer->attr.show = idletimer_tg_show;
138 ret = sysfs_create_file(idletimer_tg_kobj, &info->timer->attr.attr);
140 pr_debug("couldn't add file to sysfs");
144 list_add(&info->timer->entry, &idletimer_tg_list);
146 setup_timer(&info->timer->timer, idletimer_tg_expired,
147 (unsigned long) info->timer);
148 info->timer->refcnt = 1;
150 INIT_WORK(&info->timer->work, idletimer_tg_work);
152 mod_timer(&info->timer->timer,
153 msecs_to_jiffies(info->timeout * 1000) + jiffies);
158 kfree(info->timer->attr.attr.name);
166 * The actual xt_tables plugin.
168 static unsigned int idletimer_tg_target(struct sk_buff *skb,
169 const struct xt_action_param *par)
171 const struct idletimer_tg_info *info = par->targinfo;
173 pr_debug("resetting timer %s, timeout period %u\n",
174 info->label, info->timeout);
176 BUG_ON(!info->timer);
178 mod_timer(&info->timer->timer,
179 msecs_to_jiffies(info->timeout * 1000) + jiffies);
184 static int idletimer_tg_checkentry(const struct xt_tgchk_param *par)
186 struct idletimer_tg_info *info = par->targinfo;
189 pr_debug("checkentry targinfo%s\n", info->label);
191 if (info->timeout == 0) {
192 pr_debug("timeout value is zero\n");
195 if (info->timeout >= INT_MAX / 1000) {
196 pr_debug("timeout value is too big\n");
199 if (info->label[0] == '\0' ||
201 MAX_IDLETIMER_LABEL_SIZE) == MAX_IDLETIMER_LABEL_SIZE) {
202 pr_debug("label is empty or not nul-terminated\n");
206 mutex_lock(&list_mutex);
208 info->timer = __idletimer_tg_find_by_label(info->label);
210 info->timer->refcnt++;
211 mod_timer(&info->timer->timer,
212 msecs_to_jiffies(info->timeout * 1000) + jiffies);
214 pr_debug("increased refcnt of timer %s to %u\n",
215 info->label, info->timer->refcnt);
217 ret = idletimer_tg_create(info);
219 pr_debug("failed to create timer\n");
220 mutex_unlock(&list_mutex);
225 mutex_unlock(&list_mutex);
229 static void idletimer_tg_destroy(const struct xt_tgdtor_param *par)
231 const struct idletimer_tg_info *info = par->targinfo;
233 pr_debug("destroy targinfo %s\n", info->label);
235 mutex_lock(&list_mutex);
237 if (--info->timer->refcnt == 0) {
238 pr_debug("deleting timer %s\n", info->label);
240 list_del(&info->timer->entry);
241 del_timer_sync(&info->timer->timer);
242 cancel_work_sync(&info->timer->work);
243 sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr);
244 kfree(info->timer->attr.attr.name);
247 pr_debug("decreased refcnt of timer %s to %u\n",
248 info->label, info->timer->refcnt);
251 mutex_unlock(&list_mutex);
254 static struct xt_target idletimer_tg __read_mostly = {
256 .family = NFPROTO_UNSPEC,
257 .target = idletimer_tg_target,
258 .targetsize = sizeof(struct idletimer_tg_info),
259 .usersize = offsetof(struct idletimer_tg_info, timer),
260 .checkentry = idletimer_tg_checkentry,
261 .destroy = idletimer_tg_destroy,
265 static struct class *idletimer_tg_class;
267 static struct device *idletimer_tg_device;
269 static int __init idletimer_tg_init(void)
273 idletimer_tg_class = class_create(THIS_MODULE, "xt_idletimer");
274 err = PTR_ERR(idletimer_tg_class);
275 if (IS_ERR(idletimer_tg_class)) {
276 pr_debug("couldn't register device class\n");
280 idletimer_tg_device = device_create(idletimer_tg_class, NULL,
281 MKDEV(0, 0), NULL, "timers");
282 err = PTR_ERR(idletimer_tg_device);
283 if (IS_ERR(idletimer_tg_device)) {
284 pr_debug("couldn't register system device\n");
288 idletimer_tg_kobj = &idletimer_tg_device->kobj;
290 err = xt_register_target(&idletimer_tg);
292 pr_debug("couldn't register xt target\n");
298 device_destroy(idletimer_tg_class, MKDEV(0, 0));
300 class_destroy(idletimer_tg_class);
305 static void __exit idletimer_tg_exit(void)
307 xt_unregister_target(&idletimer_tg);
309 device_destroy(idletimer_tg_class, MKDEV(0, 0));
310 class_destroy(idletimer_tg_class);
313 module_init(idletimer_tg_init);
314 module_exit(idletimer_tg_exit);
316 MODULE_AUTHOR("Timo Teras <ext-timo.teras@nokia.com>");
317 MODULE_AUTHOR("Luciano Coelho <luciano.coelho@nokia.com>");
318 MODULE_DESCRIPTION("Xtables: idle time monitor");
319 MODULE_LICENSE("GPL v2");
320 MODULE_ALIAS("ipt_IDLETIMER");
321 MODULE_ALIAS("ip6t_IDLETIMER");