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/slab.h> 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 <[email protected]>"); 33 MODULE_DESCRIPTION("Xtables: trigger LED devices on packet match"); 34 35 /* 36 * This is declared in here (the kernel module) only, to avoid having these 37 * dependencies in userspace code. This is what xt_led_info.internal_data 38 * points to. 39 */ 40 struct xt_led_info_internal { 41 struct led_trigger netfilter_led_trigger; 42 struct timer_list timer; 43 }; 44 45 static unsigned int 46 led_tg(struct sk_buff *skb, const struct xt_target_param *par) 47 { 48 const struct xt_led_info *ledinfo = par->targinfo; 49 struct xt_led_info_internal *ledinternal = ledinfo->internal_data; 50 51 /* 52 * If "always blink" is enabled, and there's still some time until the 53 * LED will switch off, briefly switch it off now. 54 */ 55 if ((ledinfo->delay > 0) && ledinfo->always_blink && 56 timer_pending(&ledinternal->timer)) 57 led_trigger_event(&ledinternal->netfilter_led_trigger,LED_OFF); 58 59 led_trigger_event(&ledinternal->netfilter_led_trigger, LED_FULL); 60 61 /* If there's a positive delay, start/update the timer */ 62 if (ledinfo->delay > 0) { 63 mod_timer(&ledinternal->timer, 64 jiffies + msecs_to_jiffies(ledinfo->delay)); 65 66 /* Otherwise if there was no delay given, blink as fast as possible */ 67 } else if (ledinfo->delay == 0) { 68 led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF); 69 } 70 71 /* else the delay is negative, which means switch on and stay on */ 72 73 return XT_CONTINUE; 74 } 75 76 static void led_timeout_callback(unsigned long data) 77 { 78 struct xt_led_info *ledinfo = (struct xt_led_info *)data; 79 struct xt_led_info_internal *ledinternal = ledinfo->internal_data; 80 81 led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF); 82 } 83 84 static bool led_tg_check(const struct xt_tgchk_param *par) 85 { 86 struct xt_led_info *ledinfo = par->targinfo; 87 struct xt_led_info_internal *ledinternal; 88 int err; 89 90 if (ledinfo->id[0] == '\0') { 91 printk(KERN_ERR KBUILD_MODNAME ": No 'id' parameter given.\n"); 92 return false; 93 } 94 95 ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL); 96 if (!ledinternal) { 97 printk(KERN_CRIT KBUILD_MODNAME ": out of memory\n"); 98 return false; 99 } 100 101 ledinternal->netfilter_led_trigger.name = ledinfo->id; 102 103 err = led_trigger_register(&ledinternal->netfilter_led_trigger); 104 if (err) { 105 printk(KERN_CRIT KBUILD_MODNAME 106 ": led_trigger_register() failed\n"); 107 if (err == -EEXIST) 108 printk(KERN_ERR KBUILD_MODNAME 109 ": Trigger name is already in use.\n"); 110 goto exit_alloc; 111 } 112 113 /* See if we need to set up a timer */ 114 if (ledinfo->delay > 0) 115 setup_timer(&ledinternal->timer, led_timeout_callback, 116 (unsigned long)ledinfo); 117 118 ledinfo->internal_data = ledinternal; 119 120 return true; 121 122 exit_alloc: 123 kfree(ledinternal); 124 125 return false; 126 } 127 128 static void led_tg_destroy(const struct xt_tgdtor_param *par) 129 { 130 const struct xt_led_info *ledinfo = par->targinfo; 131 struct xt_led_info_internal *ledinternal = ledinfo->internal_data; 132 133 if (ledinfo->delay > 0) 134 del_timer_sync(&ledinternal->timer); 135 136 led_trigger_unregister(&ledinternal->netfilter_led_trigger); 137 kfree(ledinternal); 138 } 139 140 static struct xt_target led_tg_reg __read_mostly = { 141 .name = "LED", 142 .revision = 0, 143 .family = NFPROTO_UNSPEC, 144 .target = led_tg, 145 .targetsize = XT_ALIGN(sizeof(struct xt_led_info)), 146 .checkentry = led_tg_check, 147 .destroy = led_tg_destroy, 148 .me = THIS_MODULE, 149 }; 150 151 static int __init led_tg_init(void) 152 { 153 return xt_register_target(&led_tg_reg); 154 } 155 156 static void __exit led_tg_exit(void) 157 { 158 xt_unregister_target(&led_tg_reg); 159 } 160 161 module_init(led_tg_init); 162 module_exit(led_tg_exit); 163