162 lines
4.4 KiB
C
162 lines
4.4 KiB
C
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/*
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* xt_LED.c - netfilter target to make LEDs blink upon packet matches
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*
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* Copyright (C) 2008 Adam Nielsen <a.nielsen@shikadi.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301 USA.
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*
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/leds.h>
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#include <linux/mutex.h>
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#include <linux/netfilter/xt_LED.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Adam Nielsen <a.nielsen@shikadi.net>");
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MODULE_DESCRIPTION("Xtables: trigger LED devices on packet match");
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/*
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* This is declared in here (the kernel module) only, to avoid having these
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* dependencies in userspace code. This is what xt_led_info.internal_data
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* points to.
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*/
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struct xt_led_info_internal {
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struct led_trigger netfilter_led_trigger;
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struct timer_list timer;
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};
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static unsigned int
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led_tg(struct sk_buff *skb, const struct xt_target_param *par)
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{
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const struct xt_led_info *ledinfo = par->targinfo;
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struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
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/*
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* If "always blink" is enabled, and there's still some time until the
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* LED will switch off, briefly switch it off now.
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*/
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if ((ledinfo->delay > 0) && ledinfo->always_blink &&
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timer_pending(&ledinternal->timer))
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led_trigger_event(&ledinternal->netfilter_led_trigger,LED_OFF);
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led_trigger_event(&ledinternal->netfilter_led_trigger, LED_FULL);
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/* If there's a positive delay, start/update the timer */
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if (ledinfo->delay > 0) {
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mod_timer(&ledinternal->timer,
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jiffies + msecs_to_jiffies(ledinfo->delay));
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/* Otherwise if there was no delay given, blink as fast as possible */
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} else if (ledinfo->delay == 0) {
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led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
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}
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/* else the delay is negative, which means switch on and stay on */
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return XT_CONTINUE;
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}
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static void led_timeout_callback(unsigned long data)
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{
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struct xt_led_info *ledinfo = (struct xt_led_info *)data;
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struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
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led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
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}
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static bool led_tg_check(const struct xt_tgchk_param *par)
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{
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struct xt_led_info *ledinfo = par->targinfo;
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struct xt_led_info_internal *ledinternal;
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int err;
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if (ledinfo->id[0] == '\0') {
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printk(KERN_ERR KBUILD_MODNAME ": No 'id' parameter given.\n");
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return false;
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}
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ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL);
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if (!ledinternal) {
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printk(KERN_CRIT KBUILD_MODNAME ": out of memory\n");
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return false;
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}
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ledinternal->netfilter_led_trigger.name = ledinfo->id;
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err = led_trigger_register(&ledinternal->netfilter_led_trigger);
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if (err) {
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printk(KERN_CRIT KBUILD_MODNAME
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": led_trigger_register() failed\n");
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if (err == -EEXIST)
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printk(KERN_ERR KBUILD_MODNAME
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": Trigger name is already in use.\n");
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goto exit_alloc;
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}
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/* See if we need to set up a timer */
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if (ledinfo->delay > 0)
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setup_timer(&ledinternal->timer, led_timeout_callback,
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(unsigned long)ledinfo);
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ledinfo->internal_data = ledinternal;
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return true;
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exit_alloc:
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kfree(ledinternal);
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return false;
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}
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static void led_tg_destroy(const struct xt_tgdtor_param *par)
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{
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const struct xt_led_info *ledinfo = par->targinfo;
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struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
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if (ledinfo->delay > 0)
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del_timer_sync(&ledinternal->timer);
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led_trigger_unregister(&ledinternal->netfilter_led_trigger);
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kfree(ledinternal);
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}
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static struct xt_target led_tg_reg __read_mostly = {
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.name = "LED",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.target = led_tg,
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.targetsize = XT_ALIGN(sizeof(struct xt_led_info)),
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.checkentry = led_tg_check,
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.destroy = led_tg_destroy,
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.me = THIS_MODULE,
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};
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static int __init led_tg_init(void)
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{
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return xt_register_target(&led_tg_reg);
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}
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static void __exit led_tg_exit(void)
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{
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xt_unregister_target(&led_tg_reg);
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}
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module_init(led_tg_init);
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module_exit(led_tg_exit);
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