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