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netfilter: x_tables: add LED trigger target
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Kernel module providing implementation of LED netfilter target.  Each
instance of the target appears as a led-trigger device, which can be
associated with one or more LEDs in /sys/class/leds/

Signed-off-by: Adam Nielsen <a.nielsen@shikadi.net>
Acked-by: Richard Purdie <rpurdie@linux.intel.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
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Malvineous authored and kaber committed Feb 20, 2009
1 parent af07d24 commit 268cb38
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Showing 6 changed files with 203 additions and 0 deletions.
3 changes: 3 additions & 0 deletions drivers/leds/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -223,4 +223,7 @@ config LEDS_TRIGGER_DEFAULT_ON
This allows LEDs to be initialised in the ON state.
If unsure, say Y.

comment "iptables trigger is under Netfilter config (LED target)"
depends on LEDS_TRIGGERS

endif # NEW_LEDS
1 change: 1 addition & 0 deletions include/linux/netfilter/Kbuild
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@ header-y += xt_CLASSIFY.h
header-y += xt_CONNMARK.h
header-y += xt_CONNSECMARK.h
header-y += xt_DSCP.h
header-y += xt_LED.h
header-y += xt_MARK.h
header-y += xt_NFLOG.h
header-y += xt_NFQUEUE.h
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13 changes: 13 additions & 0 deletions include/linux/netfilter/xt_LED.h
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@@ -0,0 +1,13 @@
#ifndef _XT_LED_H
#define _XT_LED_H

struct xt_led_info {
char id[27]; /* Unique ID for this trigger in the LED class */
__u8 always_blink; /* Blink even if the LED is already on */
__u32 delay; /* Delay until LED is switched off after trigger */

/* Kernel data used in the module */
void *internal_data __attribute__((aligned(8)));
};

#endif /* _XT_LED_H */
24 changes: 24 additions & 0 deletions net/netfilter/Kconfig
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Expand Up @@ -372,6 +372,30 @@ config NETFILTER_XT_TARGET_HL
since you can easily create immortal packets that loop
forever on the network.

config NETFILTER_XT_TARGET_LED
tristate '"LED" target support'
depends on LEDS_CLASS
depends on NETFILTER_ADVANCED
help
This option adds a `LED' target, which allows you to blink LEDs in
response to particular packets passing through your machine.

This can be used to turn a spare LED into a network activity LED,
which only flashes in response to FTP transfers, for example. Or
you could have an LED which lights up for a minute or two every time
somebody connects to your machine via SSH.

You will need support for the "led" class to make this work.

To create an LED trigger for incoming SSH traffic:
iptables -A INPUT -p tcp --dport 22 -j LED --led-trigger-id ssh --led-delay 1000

Then attach the new trigger to an LED on your system:
echo netfilter-ssh > /sys/class/leds/<ledname>/trigger

For more information on the LEDs available on your system, see
Documentation/leds-class.txt

config NETFILTER_XT_TARGET_MARK
tristate '"MARK" target support'
default m if NETFILTER_ADVANCED=n
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1 change: 1 addition & 0 deletions net/netfilter/Makefile
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Expand Up @@ -46,6 +46,7 @@ obj-$(CONFIG_NETFILTER_XT_TARGET_CONNMARK) += xt_CONNMARK.o
obj-$(CONFIG_NETFILTER_XT_TARGET_CONNSECMARK) += xt_CONNSECMARK.o
obj-$(CONFIG_NETFILTER_XT_TARGET_DSCP) += xt_DSCP.o
obj-$(CONFIG_NETFILTER_XT_TARGET_HL) += xt_HL.o
obj-$(CONFIG_NETFILTER_XT_TARGET_LED) += xt_LED.o
obj-$(CONFIG_NETFILTER_XT_TARGET_MARK) += xt_MARK.o
obj-$(CONFIG_NETFILTER_XT_TARGET_NFLOG) += xt_NFLOG.o
obj-$(CONFIG_NETFILTER_XT_TARGET_NFQUEUE) += xt_NFQUEUE.o
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161 changes: 161 additions & 0 deletions net/netfilter/xt_LED.c
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/*
* xt_LED.c - netfilter target to make LEDs blink upon packet matches
*
* Copyright (C) 2008 Adam Nielsen <a.nielsen@shikadi.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*
*/

#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter/x_tables.h>
#include <linux/leds.h>
#include <linux/mutex.h>

#include <linux/netfilter/xt_LED.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Adam Nielsen <a.nielsen@shikadi.net>");
MODULE_DESCRIPTION("Xtables: trigger LED devices on packet match");

/*
* This is declared in here (the kernel module) only, to avoid having these
* dependencies in userspace code. This is what xt_led_info.internal_data
* points to.
*/
struct xt_led_info_internal {
struct led_trigger netfilter_led_trigger;
struct timer_list timer;
};

static unsigned int
led_tg(struct sk_buff *skb, const struct xt_target_param *par)
{
const struct xt_led_info *ledinfo = par->targinfo;
struct xt_led_info_internal *ledinternal = ledinfo->internal_data;

/*
* If "always blink" is enabled, and there's still some time until the
* LED will switch off, briefly switch it off now.
*/
if ((ledinfo->delay > 0) && ledinfo->always_blink &&
timer_pending(&ledinternal->timer))
led_trigger_event(&ledinternal->netfilter_led_trigger,LED_OFF);

led_trigger_event(&ledinternal->netfilter_led_trigger, LED_FULL);

/* If there's a positive delay, start/update the timer */
if (ledinfo->delay > 0) {
mod_timer(&ledinternal->timer,
jiffies + msecs_to_jiffies(ledinfo->delay));

/* Otherwise if there was no delay given, blink as fast as possible */
} else if (ledinfo->delay == 0) {
led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
}

/* else the delay is negative, which means switch on and stay on */

return XT_CONTINUE;
}

static void led_timeout_callback(unsigned long data)
{
struct xt_led_info *ledinfo = (struct xt_led_info *)data;
struct xt_led_info_internal *ledinternal = ledinfo->internal_data;

led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
}

static bool led_tg_check(const struct xt_tgchk_param *par)
{
struct xt_led_info *ledinfo = par->targinfo;
struct xt_led_info_internal *ledinternal;
int err;

if (ledinfo->id[0] == '\0') {
printk(KERN_ERR KBUILD_MODNAME ": No 'id' parameter given.\n");
return false;
}

ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL);
if (!ledinternal) {
printk(KERN_CRIT KBUILD_MODNAME ": out of memory\n");
return false;
}

ledinternal->netfilter_led_trigger.name = ledinfo->id;

err = led_trigger_register(&ledinternal->netfilter_led_trigger);
if (err) {
printk(KERN_CRIT KBUILD_MODNAME
": led_trigger_register() failed\n");
if (err == -EEXIST)
printk(KERN_ERR KBUILD_MODNAME
": Trigger name is already in use.\n");
goto exit_alloc;
}

/* See if we need to set up a timer */
if (ledinfo->delay > 0)
setup_timer(&ledinternal->timer, led_timeout_callback,
(unsigned long)ledinfo);

ledinfo->internal_data = ledinternal;

return true;

exit_alloc:
kfree(ledinternal);

return false;
}

static void led_tg_destroy(const struct xt_tgdtor_param *par)
{
const struct xt_led_info *ledinfo = par->targinfo;
struct xt_led_info_internal *ledinternal = ledinfo->internal_data;

if (ledinfo->delay > 0)
del_timer_sync(&ledinternal->timer);

led_trigger_unregister(&ledinternal->netfilter_led_trigger);
kfree(ledinternal);
}

static struct xt_target led_tg_reg __read_mostly = {
.name = "LED",
.revision = 0,
.family = NFPROTO_UNSPEC,
.target = led_tg,
.targetsize = XT_ALIGN(sizeof(struct xt_led_info)),
.checkentry = led_tg_check,
.destroy = led_tg_destroy,
.me = THIS_MODULE,
};

static int __init led_tg_init(void)
{
return xt_register_target(&led_tg_reg);
}

static void __exit led_tg_exit(void)
{
xt_unregister_target(&led_tg_reg);
}

module_init(led_tg_init);
module_exit(led_tg_exit);

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