| /* |
| * 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> |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * version 2 as published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA |
| * 02110-1301 USA |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/module.h> |
| #include <linux/timer.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_attr { |
| struct attribute attr; |
| ssize_t (*show)(struct kobject *kobj, |
| struct attribute *attr, char *buf); |
| }; |
| |
| struct idletimer_tg { |
| struct list_head entry; |
| struct timer_list timer; |
| struct work_struct work; |
| |
| struct kobject *kobj; |
| struct idletimer_tg_attr attr; |
| |
| unsigned int refcnt; |
| }; |
| |
| 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; |
| |
| BUG_ON(!label); |
| |
| 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 kobject *kobj, struct attribute *attr, |
| char *buf) |
| { |
| struct idletimer_tg *timer; |
| unsigned long expires = 0; |
| |
| mutex_lock(&list_mutex); |
| |
| timer = __idletimer_tg_find_by_label(attr->name); |
| if (timer) |
| expires = timer->timer.expires; |
| |
| mutex_unlock(&list_mutex); |
| |
| if (time_after(expires, jiffies)) |
| return sprintf(buf, "%u\n", |
| jiffies_to_msecs(expires - jiffies) / 1000); |
| |
| return sprintf(buf, "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 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; |
| } |
| |
| 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 = S_IRUGO; |
| 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; |
| |
| mod_timer(&info->timer->timer, |
| msecs_to_jiffies(info->timeout * 1000) + jiffies); |
| |
| INIT_WORK(&info->timer->work, idletimer_tg_work); |
| |
| 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); |
| |
| BUG_ON(!info->timer); |
| |
| mod_timer(&info->timer->timer, |
| msecs_to_jiffies(info->timeout * 1000) + jiffies); |
| |
| return XT_CONTINUE; |
| } |
| |
| 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); |
| |
| if (info->timeout == 0) { |
| pr_debug("timeout value is zero\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; |
| } |
| |
| 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 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 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, |
| }; |
| |
| 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_target(&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_target(&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"); |