2 * xt_LED.c - netfilter target to make LEDs blink upon packet matches
4 * Copyright (C) 2008 Adam Nielsen <a.nielsen@shikadi.net>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; version 2 of the License.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22 #include <linux/module.h>
23 #include <linux/skbuff.h>
24 #include <linux/netfilter/x_tables.h>
25 #include <linux/leds.h>
26 #include <linux/mutex.h>
28 #include <linux/netfilter/xt_LED.h>
30 MODULE_LICENSE("GPL");
31 MODULE_AUTHOR("Adam Nielsen <a.nielsen@shikadi.net>");
32 MODULE_DESCRIPTION("Xtables: trigger LED devices on packet match");
34 static LIST_HEAD(xt_led_triggers);
35 static DEFINE_MUTEX(xt_led_mutex);
38 * This is declared in here (the kernel module) only, to avoid having these
39 * dependencies in userspace code. This is what xt_led_info.internal_data
42 struct xt_led_info_internal {
43 struct list_head list;
46 struct led_trigger netfilter_led_trigger;
47 struct timer_list timer;
51 led_tg(struct sk_buff *skb, const struct xt_target_param *par)
53 const struct xt_led_info *ledinfo = par->targinfo;
54 struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
57 * If "always blink" is enabled, and there's still some time until the
58 * LED will switch off, briefly switch it off now.
60 if ((ledinfo->delay > 0) && ledinfo->always_blink &&
61 timer_pending(&ledinternal->timer))
62 led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
64 led_trigger_event(&ledinternal->netfilter_led_trigger, LED_FULL);
66 /* If there's a positive delay, start/update the timer */
67 if (ledinfo->delay > 0) {
68 mod_timer(&ledinternal->timer,
69 jiffies + msecs_to_jiffies(ledinfo->delay));
71 /* Otherwise if there was no delay given, blink as fast as possible */
72 } else if (ledinfo->delay == 0) {
73 led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
76 /* else the delay is negative, which means switch on and stay on */
81 static void led_timeout_callback(unsigned long data)
83 struct xt_led_info_internal *ledinternal = (struct xt_led_info_internal *)data;
85 led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
88 static struct xt_led_info_internal *led_trigger_lookup(const char *name)
90 struct xt_led_info_internal *ledinternal;
92 list_for_each_entry(ledinternal, &xt_led_triggers, list) {
93 if (!strcmp(name, ledinternal->netfilter_led_trigger.name)) {
100 static int led_tg_check(const struct xt_tgchk_param *par)
102 struct xt_led_info *ledinfo = par->targinfo;
103 struct xt_led_info_internal *ledinternal;
106 if (ledinfo->id[0] == '\0') {
107 pr_info("No 'id' parameter given.\n");
111 mutex_lock(&xt_led_mutex);
113 ledinternal = led_trigger_lookup(ledinfo->id);
115 ledinternal->refcnt++;
120 ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL);
122 goto exit_mutex_only;
124 ledinternal->trigger_id = kstrdup(ledinfo->id, GFP_KERNEL);
125 if (!ledinternal->trigger_id)
126 goto exit_internal_alloc;
128 ledinternal->refcnt = 1;
129 ledinternal->netfilter_led_trigger.name = ledinternal->trigger_id;
131 err = led_trigger_register(&ledinternal->netfilter_led_trigger);
133 pr_warning("led_trigger_register() failed\n");
135 pr_warning("Trigger name is already in use.\n");
139 /* See if we need to set up a timer */
140 if (ledinfo->delay > 0)
141 setup_timer(&ledinternal->timer, led_timeout_callback,
142 (unsigned long)ledinternal);
144 list_add_tail(&ledinternal->list, &xt_led_triggers);
147 mutex_unlock(&xt_led_mutex);
149 ledinfo->internal_data = ledinternal;
154 kfree(ledinternal->trigger_id);
160 mutex_unlock(&xt_led_mutex);
165 static void led_tg_destroy(const struct xt_tgdtor_param *par)
167 const struct xt_led_info *ledinfo = par->targinfo;
168 struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
170 mutex_lock(&xt_led_mutex);
172 if (--ledinternal->refcnt) {
173 mutex_unlock(&xt_led_mutex);
177 list_del(&ledinternal->list);
179 if (ledinfo->delay > 0)
180 del_timer_sync(&ledinternal->timer);
182 led_trigger_unregister(&ledinternal->netfilter_led_trigger);
184 mutex_unlock(&xt_led_mutex);
186 kfree(ledinternal->trigger_id);
190 static struct xt_target led_tg_reg __read_mostly = {
193 .family = NFPROTO_UNSPEC,
195 .targetsize = sizeof(struct xt_led_info),
196 .checkentry = led_tg_check,
197 .destroy = led_tg_destroy,
201 static int __init led_tg_init(void)
203 return xt_register_target(&led_tg_reg);
206 static void __exit led_tg_exit(void)
208 xt_unregister_target(&led_tg_reg);
211 module_init(led_tg_init);
212 module_exit(led_tg_exit);