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268cb38e AN |
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 | */ | |
8bee4bad | 21 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
268cb38e AN |
22 | #include <linux/module.h> |
23 | #include <linux/skbuff.h> | |
24 | #include <linux/netfilter/x_tables.h> | |
5a0e3ad6 | 25 | #include <linux/slab.h> |
268cb38e AN |
26 | #include <linux/leds.h> |
27 | #include <linux/mutex.h> | |
28 | ||
29 | #include <linux/netfilter/xt_LED.h> | |
30 | ||
31 | MODULE_LICENSE("GPL"); | |
32 | MODULE_AUTHOR("Adam Nielsen <a.nielsen@shikadi.net>"); | |
33 | MODULE_DESCRIPTION("Xtables: trigger LED devices on packet match"); | |
f1e231a3 JE |
34 | MODULE_ALIAS("ipt_LED"); |
35 | MODULE_ALIAS("ip6t_LED"); | |
268cb38e | 36 | |
b660d048 AN |
37 | static LIST_HEAD(xt_led_triggers); |
38 | static DEFINE_MUTEX(xt_led_mutex); | |
39 | ||
268cb38e AN |
40 | /* |
41 | * This is declared in here (the kernel module) only, to avoid having these | |
42 | * dependencies in userspace code. This is what xt_led_info.internal_data | |
43 | * points to. | |
44 | */ | |
45 | struct xt_led_info_internal { | |
b660d048 AN |
46 | struct list_head list; |
47 | int refcnt; | |
48 | char *trigger_id; | |
268cb38e AN |
49 | struct led_trigger netfilter_led_trigger; |
50 | struct timer_list timer; | |
51 | }; | |
52 | ||
8452e6ff JP |
53 | #define XT_LED_BLINK_DELAY 50 /* ms */ |
54 | ||
268cb38e | 55 | static unsigned int |
4b560b44 | 56 | led_tg(struct sk_buff *skb, const struct xt_action_param *par) |
268cb38e AN |
57 | { |
58 | const struct xt_led_info *ledinfo = par->targinfo; | |
59 | struct xt_led_info_internal *ledinternal = ledinfo->internal_data; | |
8452e6ff | 60 | unsigned long led_delay = XT_LED_BLINK_DELAY; |
268cb38e AN |
61 | |
62 | /* | |
63 | * If "always blink" is enabled, and there's still some time until the | |
64 | * LED will switch off, briefly switch it off now. | |
65 | */ | |
66 | if ((ledinfo->delay > 0) && ledinfo->always_blink && | |
67 | timer_pending(&ledinternal->timer)) | |
8452e6ff JP |
68 | led_trigger_blink_oneshot(&ledinternal->netfilter_led_trigger, |
69 | &led_delay, &led_delay, 1); | |
70 | else | |
71 | led_trigger_event(&ledinternal->netfilter_led_trigger, LED_FULL); | |
268cb38e AN |
72 | |
73 | /* If there's a positive delay, start/update the timer */ | |
74 | if (ledinfo->delay > 0) { | |
75 | mod_timer(&ledinternal->timer, | |
76 | jiffies + msecs_to_jiffies(ledinfo->delay)); | |
77 | ||
78 | /* Otherwise if there was no delay given, blink as fast as possible */ | |
79 | } else if (ledinfo->delay == 0) { | |
80 | led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF); | |
81 | } | |
82 | ||
83 | /* else the delay is negative, which means switch on and stay on */ | |
84 | ||
85 | return XT_CONTINUE; | |
86 | } | |
87 | ||
88 | static void led_timeout_callback(unsigned long data) | |
89 | { | |
b660d048 | 90 | struct xt_led_info_internal *ledinternal = (struct xt_led_info_internal *)data; |
268cb38e AN |
91 | |
92 | led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF); | |
93 | } | |
94 | ||
b660d048 AN |
95 | static struct xt_led_info_internal *led_trigger_lookup(const char *name) |
96 | { | |
97 | struct xt_led_info_internal *ledinternal; | |
98 | ||
99 | list_for_each_entry(ledinternal, &xt_led_triggers, list) { | |
100 | if (!strcmp(name, ledinternal->netfilter_led_trigger.name)) { | |
101 | return ledinternal; | |
102 | } | |
103 | } | |
104 | return NULL; | |
105 | } | |
106 | ||
135367b8 | 107 | static int led_tg_check(const struct xt_tgchk_param *par) |
268cb38e AN |
108 | { |
109 | struct xt_led_info *ledinfo = par->targinfo; | |
110 | struct xt_led_info_internal *ledinternal; | |
111 | int err; | |
112 | ||
113 | if (ledinfo->id[0] == '\0') { | |
8bee4bad | 114 | pr_info("No 'id' parameter given.\n"); |
d6b00a53 | 115 | return -EINVAL; |
268cb38e AN |
116 | } |
117 | ||
b660d048 AN |
118 | mutex_lock(&xt_led_mutex); |
119 | ||
120 | ledinternal = led_trigger_lookup(ledinfo->id); | |
121 | if (ledinternal) { | |
122 | ledinternal->refcnt++; | |
123 | goto out; | |
124 | } | |
125 | ||
126 | err = -ENOMEM; | |
268cb38e | 127 | ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL); |
85bc3f38 | 128 | if (!ledinternal) |
b660d048 AN |
129 | goto exit_mutex_only; |
130 | ||
131 | ledinternal->trigger_id = kstrdup(ledinfo->id, GFP_KERNEL); | |
132 | if (!ledinternal->trigger_id) | |
133 | goto exit_internal_alloc; | |
268cb38e | 134 | |
b660d048 AN |
135 | ledinternal->refcnt = 1; |
136 | ledinternal->netfilter_led_trigger.name = ledinternal->trigger_id; | |
268cb38e AN |
137 | |
138 | err = led_trigger_register(&ledinternal->netfilter_led_trigger); | |
139 | if (err) { | |
a2b60c75 | 140 | pr_err("Trigger name is already in use.\n"); |
268cb38e AN |
141 | goto exit_alloc; |
142 | } | |
143 | ||
144 | /* See if we need to set up a timer */ | |
145 | if (ledinfo->delay > 0) | |
146 | setup_timer(&ledinternal->timer, led_timeout_callback, | |
b660d048 AN |
147 | (unsigned long)ledinternal); |
148 | ||
149 | list_add_tail(&ledinternal->list, &xt_led_triggers); | |
150 | ||
151 | out: | |
152 | mutex_unlock(&xt_led_mutex); | |
268cb38e AN |
153 | |
154 | ledinfo->internal_data = ledinternal; | |
b660d048 | 155 | |
d6b00a53 | 156 | return 0; |
268cb38e AN |
157 | |
158 | exit_alloc: | |
b660d048 AN |
159 | kfree(ledinternal->trigger_id); |
160 | ||
161 | exit_internal_alloc: | |
268cb38e | 162 | kfree(ledinternal); |
b660d048 AN |
163 | |
164 | exit_mutex_only: | |
165 | mutex_unlock(&xt_led_mutex); | |
166 | ||
4a5a5c73 | 167 | return err; |
268cb38e AN |
168 | } |
169 | ||
170 | static void led_tg_destroy(const struct xt_tgdtor_param *par) | |
171 | { | |
172 | const struct xt_led_info *ledinfo = par->targinfo; | |
173 | struct xt_led_info_internal *ledinternal = ledinfo->internal_data; | |
174 | ||
b660d048 AN |
175 | mutex_lock(&xt_led_mutex); |
176 | ||
177 | if (--ledinternal->refcnt) { | |
178 | mutex_unlock(&xt_led_mutex); | |
179 | return; | |
180 | } | |
181 | ||
182 | list_del(&ledinternal->list); | |
183 | ||
268cb38e AN |
184 | if (ledinfo->delay > 0) |
185 | del_timer_sync(&ledinternal->timer); | |
186 | ||
187 | led_trigger_unregister(&ledinternal->netfilter_led_trigger); | |
b660d048 AN |
188 | |
189 | mutex_unlock(&xt_led_mutex); | |
190 | ||
191 | kfree(ledinternal->trigger_id); | |
268cb38e AN |
192 | kfree(ledinternal); |
193 | } | |
194 | ||
195 | static struct xt_target led_tg_reg __read_mostly = { | |
196 | .name = "LED", | |
197 | .revision = 0, | |
198 | .family = NFPROTO_UNSPEC, | |
199 | .target = led_tg, | |
7d5f7ed8 | 200 | .targetsize = sizeof(struct xt_led_info), |
268cb38e AN |
201 | .checkentry = led_tg_check, |
202 | .destroy = led_tg_destroy, | |
203 | .me = THIS_MODULE, | |
204 | }; | |
205 | ||
206 | static int __init led_tg_init(void) | |
207 | { | |
208 | return xt_register_target(&led_tg_reg); | |
209 | } | |
210 | ||
211 | static void __exit led_tg_exit(void) | |
212 | { | |
213 | xt_unregister_target(&led_tg_reg); | |
214 | } | |
215 | ||
216 | module_init(led_tg_init); | |
217 | module_exit(led_tg_exit); |