Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * xt_LED.c - netfilter target to make LEDs blink upon packet matches
3 *
4 * Copyright (C) 2008 Adam Nielsen <a.nielsen@shikadi.net>
5 *
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.
9 *
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.
14 *
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
18 * 02110-1301 USA.
19 *
20 */
21
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>
27
28#include <linux/netfilter/xt_LED.h>
29
30MODULE_LICENSE("GPL");
31MODULE_AUTHOR("Adam Nielsen <a.nielsen@shikadi.net>");
32MODULE_DESCRIPTION("Xtables: trigger LED devices on packet match");
33
34/*
35 * This is declared in here (the kernel module) only, to avoid having these
36 * dependencies in userspace code. This is what xt_led_info.internal_data
37 * points to.
38 */
39struct xt_led_info_internal {
40 struct led_trigger netfilter_led_trigger;
41 struct timer_list timer;
42};
43
44static unsigned int
45led_tg(struct sk_buff *skb, const struct xt_target_param *par)
46{
47 const struct xt_led_info *ledinfo = par->targinfo;
48 struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
49
50 /*
51 * If "always blink" is enabled, and there's still some time until the
52 * LED will switch off, briefly switch it off now.
53 */
54 if ((ledinfo->delay > 0) && ledinfo->always_blink &&
55 timer_pending(&ledinternal->timer))
56 led_trigger_event(&ledinternal->netfilter_led_trigger,LED_OFF);
57
58 led_trigger_event(&ledinternal->netfilter_led_trigger, LED_FULL);
59
60 /* If there's a positive delay, start/update the timer */
61 if (ledinfo->delay > 0) {
62 mod_timer(&ledinternal->timer,
63 jiffies + msecs_to_jiffies(ledinfo->delay));
64
65 /* Otherwise if there was no delay given, blink as fast as possible */
66 } else if (ledinfo->delay == 0) {
67 led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
68 }
69
70 /* else the delay is negative, which means switch on and stay on */
71
72 return XT_CONTINUE;
73}
74
75static void led_timeout_callback(unsigned long data)
76{
77 struct xt_led_info *ledinfo = (struct xt_led_info *)data;
78 struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
79
80 led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
81}
82
83static bool led_tg_check(const struct xt_tgchk_param *par)
84{
85 struct xt_led_info *ledinfo = par->targinfo;
86 struct xt_led_info_internal *ledinternal;
87 int err;
88
89 if (ledinfo->id[0] == '\0') {
90 printk(KERN_ERR KBUILD_MODNAME ": No 'id' parameter given.\n");
91 return false;
92 }
93
94 ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL);
95 if (!ledinternal) {
96 printk(KERN_CRIT KBUILD_MODNAME ": out of memory\n");
97 return false;
98 }
99
100 ledinternal->netfilter_led_trigger.name = ledinfo->id;
101
102 err = led_trigger_register(&ledinternal->netfilter_led_trigger);
103 if (err) {
104 printk(KERN_CRIT KBUILD_MODNAME
105 ": led_trigger_register() failed\n");
106 if (err == -EEXIST)
107 printk(KERN_ERR KBUILD_MODNAME
108 ": Trigger name is already in use.\n");
109 goto exit_alloc;
110 }
111
112 /* See if we need to set up a timer */
113 if (ledinfo->delay > 0)
114 setup_timer(&ledinternal->timer, led_timeout_callback,
115 (unsigned long)ledinfo);
116
117 ledinfo->internal_data = ledinternal;
118
119 return true;
120
121exit_alloc:
122 kfree(ledinternal);
123
124 return false;
125}
126
127static void led_tg_destroy(const struct xt_tgdtor_param *par)
128{
129 const struct xt_led_info *ledinfo = par->targinfo;
130 struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
131
132 if (ledinfo->delay > 0)
133 del_timer_sync(&ledinternal->timer);
134
135 led_trigger_unregister(&ledinternal->netfilter_led_trigger);
136 kfree(ledinternal);
137}
138
139static struct xt_target led_tg_reg __read_mostly = {
140 .name = "LED",
141 .revision = 0,
142 .family = NFPROTO_UNSPEC,
143 .target = led_tg,
144 .targetsize = XT_ALIGN(sizeof(struct xt_led_info)),
145 .checkentry = led_tg_check,
146 .destroy = led_tg_destroy,
147 .me = THIS_MODULE,
148};
149
150static int __init led_tg_init(void)
151{
152 return xt_register_target(&led_tg_reg);
153}
154
155static void __exit led_tg_exit(void)
156{
157 xt_unregister_target(&led_tg_reg);
158}
159
160module_init(led_tg_init);
161module_exit(led_tg_exit);