1 /* 2 * xt_LED.c - netfilter target to make LEDs blink upon packet matches 3 * 4 * Copyright (C) 2008 Adam Nielsen <[email protected]> 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 30 MODULE_LICENSE("GPL"); 31 MODULE_AUTHOR("Adam Nielsen <[email protected]>"); 32 MODULE_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 */ 39 struct xt_led_info_internal { 40 struct led_trigger netfilter_led_trigger; 41 struct timer_list timer; 42 }; 43 44 static unsigned int 45 led_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 75 static 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 83 static 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; 120 121 exit_alloc: 122 kfree(ledinternal); 123 124 return false; 125 } 126 127 static 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 } 138 139 static 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 }; 149 150 static int __init led_tg_init(void) 151 { 152 return xt_register_target(&led_tg_reg); 153 } 154 155 static void __exit led_tg_exit(void) 156 { 157 xt_unregister_target(&led_tg_reg); 158 } 159 160 module_init(led_tg_init); 161 module_exit(led_tg_exit); 162