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// SPDX-License-Identifier: GPL-2.0-only
/*
* xt_LED.c - netfilter target to make LEDs blink upon packet matches
*
* Copyright (C) 2008 Adam Nielsen <a.nielsen@shikadi.net>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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");
MODULE_ALIAS("ipt_LED");
MODULE_ALIAS("ip6t_LED");
static LIST_HEAD(xt_led_triggers);
static DEFINE_MUTEX(xt_led_mutex);
/*
* 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 list_head list;
int refcnt;
char *trigger_id;
struct led_trigger netfilter_led_trigger;
struct timer_list timer;
};
#define XT_LED_BLINK_DELAY 50 /* ms */
static unsigned int
led_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_led_info *ledinfo = par->targinfo;
struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
unsigned long led_delay = XT_LED_BLINK_DELAY;
/*
* 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_blink_oneshot(&ledinternal->netfilter_led_trigger,
&led_delay, &led_delay, 1);
else
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(struct timer_list *t)
{
struct xt_led_info_internal *ledinternal = from_timer(ledinternal, t,
timer);
led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
}
static struct xt_led_info_internal *led_trigger_lookup(const char *name)
{
struct xt_led_info_internal *ledinternal;
list_for_each_entry(ledinternal, &xt_led_triggers, list) {
if (!strcmp(name, ledinternal->netfilter_led_trigger.name)) {
return ledinternal;
}
}
return NULL;
}
static int 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')
return -EINVAL;
mutex_lock(&xt_led_mutex);
ledinternal = led_trigger_lookup(ledinfo->id);
if (ledinternal) {
ledinternal->refcnt++;
goto out;
}
err = -ENOMEM;
ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL);
if (!ledinternal)
goto exit_mutex_only;
ledinternal->trigger_id = kstrdup(ledinfo->id, GFP_KERNEL);
if (!ledinternal->trigger_id)
goto exit_internal_alloc;
ledinternal->refcnt = 1;
ledinternal->netfilter_led_trigger.name = ledinternal->trigger_id;
err = led_trigger_register(&ledinternal->netfilter_led_trigger);
if (err) {
pr_info_ratelimited("Trigger name is already in use.\n");
goto exit_alloc;
}
/* Since the letinternal timer can be shared between multiple targets,
* always set it up, even if the current target does not need it
*/
timer_setup(&ledinternal->timer, led_timeout_callback, 0);
list_add_tail(&ledinternal->list, &xt_led_triggers);
out:
mutex_unlock(&xt_led_mutex);
ledinfo->internal_data = ledinternal;
return 0;
exit_alloc:
kfree(ledinternal->trigger_id);
exit_internal_alloc:
kfree(ledinternal);
exit_mutex_only:
mutex_unlock(&xt_led_mutex);
return err;
}
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;
mutex_lock(&xt_led_mutex);
if (--ledinternal->refcnt) {
mutex_unlock(&xt_led_mutex);
return;
}
list_del(&ledinternal->list);
del_timer_sync(&ledinternal->timer);
led_trigger_unregister(&ledinternal->netfilter_led_trigger);
mutex_unlock(&xt_led_mutex);
kfree(ledinternal->trigger_id);
kfree(ledinternal);
}
static struct xt_target led_tg_reg __read_mostly = {
.name = "LED",
.revision = 0,
.family = NFPROTO_UNSPEC,
.target = led_tg,
.targetsize = sizeof(struct xt_led_info),
.usersize = offsetof(struct xt_led_info, internal_data),
.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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