Adam Nielsen | 268cb38 | 2009-02-20 10:55:14 +0100 | [diff] [blame] | 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 | |
| 30 | MODULE_LICENSE("GPL"); |
| 31 | MODULE_AUTHOR("Adam Nielsen <a.nielsen@shikadi.net>"); |
| 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); |