// SPDX-License-Identifier: GPL-2.0-only
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/*
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* xt_LED.c - netfilter target to make LEDs blink upon packet matches
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*
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* Copyright (C) 2008 Adam Nielsen <a.nielsen@shikadi.net>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/slab.h>
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#include <linux/leds.h>
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#include <linux/mutex.h>
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#include <linux/netfilter/xt_LED.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Adam Nielsen <a.nielsen@shikadi.net>");
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MODULE_DESCRIPTION("Xtables: trigger LED devices on packet match");
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MODULE_ALIAS("ipt_LED");
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MODULE_ALIAS("ip6t_LED");
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static LIST_HEAD(xt_led_triggers);
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static DEFINE_MUTEX(xt_led_mutex);
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/*
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* This is declared in here (the kernel module) only, to avoid having these
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* dependencies in userspace code. This is what xt_led_info.internal_data
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* points to.
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*/
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struct xt_led_info_internal {
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struct list_head list;
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int refcnt;
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char *trigger_id;
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struct led_trigger netfilter_led_trigger;
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struct timer_list timer;
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};
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#define XT_LED_BLINK_DELAY 50 /* ms */
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static unsigned int
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led_tg(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct xt_led_info *ledinfo = par->targinfo;
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struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
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unsigned long led_delay = XT_LED_BLINK_DELAY;
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/*
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* If "always blink" is enabled, and there's still some time until the
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* LED will switch off, briefly switch it off now.
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*/
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if ((ledinfo->delay > 0) && ledinfo->always_blink &&
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timer_pending(&ledinternal->timer))
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led_trigger_blink_oneshot(&ledinternal->netfilter_led_trigger,
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&led_delay, &led_delay, 1);
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else
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led_trigger_event(&ledinternal->netfilter_led_trigger, LED_FULL);
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/* If there's a positive delay, start/update the timer */
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if (ledinfo->delay > 0) {
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mod_timer(&ledinternal->timer,
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jiffies + msecs_to_jiffies(ledinfo->delay));
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/* Otherwise if there was no delay given, blink as fast as possible */
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} else if (ledinfo->delay == 0) {
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led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
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}
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/* else the delay is negative, which means switch on and stay on */
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return XT_CONTINUE;
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}
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static void led_timeout_callback(struct timer_list *t)
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{
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struct xt_led_info_internal *ledinternal = from_timer(ledinternal, t,
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timer);
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led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
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}
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static struct xt_led_info_internal *led_trigger_lookup(const char *name)
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{
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struct xt_led_info_internal *ledinternal;
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list_for_each_entry(ledinternal, &xt_led_triggers, list) {
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if (!strcmp(name, ledinternal->netfilter_led_trigger.name)) {
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return ledinternal;
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}
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}
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return NULL;
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}
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static int led_tg_check(const struct xt_tgchk_param *par)
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{
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struct xt_led_info *ledinfo = par->targinfo;
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struct xt_led_info_internal *ledinternal;
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int err;
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if (ledinfo->id[0] == '\0')
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return -EINVAL;
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mutex_lock(&xt_led_mutex);
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ledinternal = led_trigger_lookup(ledinfo->id);
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if (ledinternal) {
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ledinternal->refcnt++;
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goto out;
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}
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err = -ENOMEM;
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ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL);
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if (!ledinternal)
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goto exit_mutex_only;
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ledinternal->trigger_id = kstrdup(ledinfo->id, GFP_KERNEL);
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if (!ledinternal->trigger_id)
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goto exit_internal_alloc;
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ledinternal->refcnt = 1;
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ledinternal->netfilter_led_trigger.name = ledinternal->trigger_id;
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err = led_trigger_register(&ledinternal->netfilter_led_trigger);
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if (err) {
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pr_info_ratelimited("Trigger name is already in use.\n");
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goto exit_alloc;
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}
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/* Since the letinternal timer can be shared between multiple targets,
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* always set it up, even if the current target does not need it
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*/
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timer_setup(&ledinternal->timer, led_timeout_callback, 0);
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list_add_tail(&ledinternal->list, &xt_led_triggers);
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out:
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mutex_unlock(&xt_led_mutex);
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ledinfo->internal_data = ledinternal;
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return 0;
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exit_alloc:
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kfree(ledinternal->trigger_id);
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exit_internal_alloc:
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kfree(ledinternal);
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exit_mutex_only:
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mutex_unlock(&xt_led_mutex);
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return err;
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}
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static void led_tg_destroy(const struct xt_tgdtor_param *par)
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{
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const struct xt_led_info *ledinfo = par->targinfo;
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struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
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mutex_lock(&xt_led_mutex);
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if (--ledinternal->refcnt) {
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mutex_unlock(&xt_led_mutex);
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return;
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}
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list_del(&ledinternal->list);
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del_timer_sync(&ledinternal->timer);
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led_trigger_unregister(&ledinternal->netfilter_led_trigger);
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mutex_unlock(&xt_led_mutex);
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kfree(ledinternal->trigger_id);
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kfree(ledinternal);
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}
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static struct xt_target led_tg_reg __read_mostly = {
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.name = "LED",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.target = led_tg,
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.targetsize = sizeof(struct xt_led_info),
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.usersize = offsetof(struct xt_led_info, internal_data),
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.checkentry = led_tg_check,
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.destroy = led_tg_destroy,
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.me = THIS_MODULE,
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};
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static int __init led_tg_init(void)
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{
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return xt_register_target(&led_tg_reg);
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}
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static void __exit led_tg_exit(void)
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{
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xt_unregister_target(&led_tg_reg);
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}
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module_init(led_tg_init);
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module_exit(led_tg_exit);
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