blob: 75bd0e5dd312e1d9e807f15de87cb4b0e2d3f387 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* 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>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/timer.h>
#include <linux/alarmtimer.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 {
struct list_head entry;
struct alarm alarm;
struct timer_list timer;
struct work_struct work;
struct kobject *kobj;
struct device_attribute attr;
unsigned int refcnt;
u8 timer_type;
};
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;
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 device *dev,
struct device_attribute *attr, char *buf)
{
struct idletimer_tg *timer;
unsigned long expires = 0;
struct timespec64 ktimespec = {};
long time_diff = 0;
mutex_lock(&list_mutex);
timer = __idletimer_tg_find_by_label(attr->attr.name);
if (timer) {
if (timer->timer_type & XT_IDLETIMER_ALARM) {
ktime_t expires_alarm = alarm_expires_remaining(&timer->alarm);
ktimespec = ktime_to_timespec64(expires_alarm);
time_diff = ktimespec.tv_sec;
} else {
expires = timer->timer.expires;
time_diff = jiffies_to_msecs(expires - jiffies) / 1000;
}
}
mutex_unlock(&list_mutex);
if (time_after(expires, jiffies) || ktimespec.tv_sec > 0)
return snprintf(buf, PAGE_SIZE, "%ld\n", time_diff);
return snprintf(buf, PAGE_SIZE, "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 enum alarmtimer_restart idletimer_tg_alarmproc(struct alarm *alarm,
ktime_t now)
{
struct idletimer_tg *timer = alarm->data;
pr_debug("alarm %s expired\n", timer->attr.attr.name);
schedule_work(&timer->work);
return ALARMTIMER_NORESTART;
}
static int idletimer_check_sysfs_name(const char *name, unsigned int size)
{
int ret;
ret = xt_check_proc_name(name, size);
if (ret < 0)
return ret;
if (!strcmp(name, "power") ||
!strcmp(name, "subsystem") ||
!strcmp(name, "uevent"))
return -EINVAL;
return 0;
}
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;
}
ret = idletimer_check_sysfs_name(info->label, sizeof(info->label));
if (ret < 0)
goto out_free_timer;
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 = 0444;
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;
INIT_WORK(&info->timer->work, idletimer_tg_work);
mod_timer(&info->timer->timer,
msecs_to_jiffies(info->timeout * 1000) + jiffies);
return 0;
out_free_attr:
kfree(info->timer->attr.attr.name);
out_free_timer:
kfree(info->timer);
out:
return ret;
}
static int idletimer_tg_create_v1(struct idletimer_tg_info_v1 *info)
{
int ret;
info->timer = kmalloc(sizeof(*info->timer), GFP_KERNEL);
if (!info->timer) {
ret = -ENOMEM;
goto out;
}
ret = idletimer_check_sysfs_name(info->label, sizeof(info->label));
if (ret < 0)
goto out_free_timer;
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 = 0444;
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;
}
/* notify userspace */
kobject_uevent(idletimer_tg_kobj,KOBJ_ADD);
list_add(&info->timer->entry, &idletimer_tg_list);
pr_debug("timer type value is %u", info->timer_type);
info->timer->timer_type = info->timer_type;
info->timer->refcnt = 1;
INIT_WORK(&info->timer->work, idletimer_tg_work);
if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
ktime_t tout;
alarm_init(&info->timer->alarm, ALARM_BOOTTIME,
idletimer_tg_alarmproc);
info->timer->alarm.data = info->timer;
tout = ktime_set(info->timeout, 0);
alarm_start_relative(&info->timer->alarm, tout);
} else {
timer_setup(&info->timer->timer, idletimer_tg_expired, 0);
mod_timer(&info->timer->timer,
msecs_to_jiffies(info->timeout * 1000) + jiffies);
}
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);
mod_timer(&info->timer->timer,
msecs_to_jiffies(info->timeout * 1000) + jiffies);
return XT_CONTINUE;
}
/*
* The actual xt_tables plugin.
*/
static unsigned int idletimer_tg_target_v1(struct sk_buff *skb,
const struct xt_action_param *par)
{
const struct idletimer_tg_info_v1 *info = par->targinfo;
pr_debug("resetting timer %s, timeout period %u\n",
info->label, info->timeout);
if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
ktime_t tout = ktime_set(info->timeout, 0);
alarm_start_relative(&info->timer->alarm, tout);
} else {
mod_timer(&info->timer->timer,
msecs_to_jiffies(info->timeout * 1000) + jiffies);
}
return XT_CONTINUE;
}
static int idletimer_tg_helper(struct idletimer_tg_info *info)
{
if (info->timeout == 0) {
pr_debug("timeout value is zero\n");
return -EINVAL;
}
if (info->timeout >= INT_MAX / 1000) {
pr_debug("timeout value is too big\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;
}
return 0;
}
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);
ret = idletimer_tg_helper(info);
if(ret < 0)
{
pr_debug("checkentry helper return invalid\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 int idletimer_tg_checkentry_v1(const struct xt_tgchk_param *par)
{
struct idletimer_tg_info_v1 *info = par->targinfo;
int ret;
pr_debug("checkentry targinfo%s\n", info->label);
ret = idletimer_tg_helper((struct idletimer_tg_info *)info);
if(ret < 0)
{
pr_debug("checkentry helper return invalid\n");
return -EINVAL;
}
if (info->timer_type > XT_IDLETIMER_ALARM) {
pr_debug("invalid value for timer type\n");
return -EINVAL;
}
mutex_lock(&list_mutex);
info->timer = __idletimer_tg_find_by_label(info->label);
if (info->timer) {
if (info->timer->timer_type != info->timer_type) {
pr_debug("Adding/Replacing rule with same label and different timer type is not allowed\n");
mutex_unlock(&list_mutex);
return -EINVAL;
}
info->timer->refcnt++;
if (info->timer_type & XT_IDLETIMER_ALARM) {
/* calculate remaining expiry time */
ktime_t tout = alarm_expires_remaining(&info->timer->alarm);
struct timespec64 ktimespec = ktime_to_timespec64(tout);
if (ktimespec.tv_sec > 0) {
pr_debug("time_expiry_remaining %lld\n",
ktimespec.tv_sec);
alarm_start_relative(&info->timer->alarm, tout);
}
} else {
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_v1(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 void idletimer_tg_destroy_v1(const struct xt_tgdtor_param *par)
{
const struct idletimer_tg_info_v1 *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);
if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
alarm_cancel(&info->timer->alarm);
} else {
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,
},
{
.name = "IDLETIMER",
.family = NFPROTO_UNSPEC,
.revision = 1,
.target = idletimer_tg_target_v1,
.targetsize = sizeof(struct idletimer_tg_info_v1),
.usersize = offsetof(struct idletimer_tg_info_v1, timer),
.checkentry = idletimer_tg_checkentry_v1,
.destroy = idletimer_tg_destroy_v1,
.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_targets(idletimer_tg, ARRAY_SIZE(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_targets(idletimer_tg, ARRAY_SIZE(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");