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/*
* xt_LED.c - netfilter target to make LEDs blink upon packet matches
*
* Copyright (C) 2008 Adam Nielsen <a.nielsen@shikadi.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* 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 Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter/x_tables.h>
#include <linux/slab.h>
#include <linux/leds.h>
#include <linux/mutex.h>
#include <linux/netfilter/xt_LED.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Adam Nielsen <a.nielsen@shikadi.net>");
MODULE_DESCRIPTION("Xtables: trigger LED devices on packet match");
/*
* This is declared in here (the kernel module) only, to avoid having these
* dependencies in userspace code. This is what xt_led_info.internal_data
* points to.
*/
struct xt_led_info_internal {
struct led_trigger netfilter_led_trigger;
struct timer_list timer;
};
static unsigned int
led_tg(struct sk_buff *skb, const struct xt_target_param *par)
{
const struct xt_led_info *ledinfo = par->targinfo;
struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
/*
* If "always blink" is enabled, and there's still some time until the
* LED will switch off, briefly switch it off now.
*/
if ((ledinfo->delay > 0) && ledinfo->always_blink &&
timer_pending(&ledinternal->timer))
led_trigger_event(&ledinternal->netfilter_led_trigger,LED_OFF);
led_trigger_event(&ledinternal->netfilter_led_trigger, LED_FULL);
/* If there's a positive delay, start/update the timer */
if (ledinfo->delay > 0) {
mod_timer(&ledinternal->timer,
jiffies + msecs_to_jiffies(ledinfo->delay));
/* Otherwise if there was no delay given, blink as fast as possible */
} else if (ledinfo->delay == 0) {
led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
}
/* else the delay is negative, which means switch on and stay on */
return XT_CONTINUE;
}
static void led_timeout_callback(unsigned long data)
{
struct xt_led_info *ledinfo = (struct xt_led_info *)data;
struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
}
static bool led_tg_check(const struct xt_tgchk_param *par)
{
struct xt_led_info *ledinfo = par->targinfo;
struct xt_led_info_internal *ledinternal;
int err;
if (ledinfo->id[0] == '\0') {
printk(KERN_ERR KBUILD_MODNAME ": No 'id' parameter given.\n");
return false;
}
ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL);
if (!ledinternal) {
printk(KERN_CRIT KBUILD_MODNAME ": out of memory\n");
return false;
}
ledinternal->netfilter_led_trigger.name = ledinfo->id;
err = led_trigger_register(&ledinternal->netfilter_led_trigger);
if (err) {
printk(KERN_CRIT KBUILD_MODNAME
": led_trigger_register() failed\n");
if (err == -EEXIST)
printk(KERN_ERR KBUILD_MODNAME
": Trigger name is already in use.\n");
goto exit_alloc;
}
/* See if we need to set up a timer */
if (ledinfo->delay > 0)
setup_timer(&ledinternal->timer, led_timeout_callback,
(unsigned long)ledinfo);
ledinfo->internal_data = ledinternal;
return true;
exit_alloc:
kfree(ledinternal);
return false;
}
static void led_tg_destroy(const struct xt_tgdtor_param *par)
{
const struct xt_led_info *ledinfo = par->targinfo;
struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
if (ledinfo->delay > 0)
del_timer_sync(&ledinternal->timer);
led_trigger_unregister(&ledinternal->netfilter_led_trigger);
kfree(ledinternal);
}
static struct xt_target led_tg_reg __read_mostly = {
.name = "LED",
.revision = 0,
.family = NFPROTO_UNSPEC,
.target = led_tg,
.targetsize = XT_ALIGN(sizeof(struct xt_led_info)),
.checkentry = led_tg_check,
.destroy = led_tg_destroy,
.me = THIS_MODULE,
};
static int __init led_tg_init(void)
{
return xt_register_target(&led_tg_reg);
}
static void __exit led_tg_exit(void)
{
xt_unregister_target(&led_tg_reg);
}
module_init(led_tg_init);
module_exit(led_tg_exit);
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