openwrt-leds-as-notification

Use the status leds of your router for any action you want

How does this work

The led_action function uses the Linux kernel LED API which consists in writable userspace files. led_action simply writes the appropriate values in those files. This avoids verbosity and simplifies maintenance.

Add your own profile

Have a look at the /sys/class/leds directory of your system and create a new file based on ./profiles/dg834gv4.profile.

Synopsis

led_action $led_name $action $key0:$value0 $key1:$value1 $keyn-1:$valuen-1

Examples

Testing directly from the shell

. ./profiles/dg834gv4.profile
. ./led.sh

led_action adsl on
led_action power_red blink delay_on:100 delay_off:1000
led_action adsl off
led_action power_red off

Usage through a script

In these examples this script is called do_ping.sh.

#!/bin/ash

. ./profiles/dg834gv4.profile
. ./led.sh

clear_leds()
{
    led_action power_green off
    led_action power_red off
    led_action adsl off
    led_action internet off
}

main()
{
    clear_leds
    while true; do
        # Do your stuff here. For example you could check for
        # internet and DNS functionality on two different leds.
        ping -c 1 8.8.8.8 || led_action adsl blink delay_on:1000 delay_off:20
        ping -c 1 google.com || led_action internet blink delay_on:10 delay_off:10

        # Set a polling timeout.
        sleep 600

        # You are responsible to clear the leds once the timeout ends.
        clear_leds
    done
}

main

OpenWrt stuff

Start service at boot with routing and DNS settings

This works in case you cannot install packages on your OpenWrt system (this is my case, due to low memory). In this case touch a new file called /etc/init.d/startup with the following content. This will create a system service that will run at startup.

#!/bin/sh /etc/rc.common

START=99
STOP=99

start()
{
        router_address="192.168.1.1"
        DNS_server_address="8.8.8.8"
        sleep 60
        route add default gateway $router_address br-lan
        echo "nameserver $DNS_server_address" > /etc/resolv.conf
        cd /root/leds
        /root/leds/do_ping.sh &

}

stop()
{
        killall do_ping.sh
}

Then:

chmod +x /etc/init.d/startup
/etc/init.d/startup enable
/etc/init.d/startup enabled && echo "OK" || echo "ERROR"

Bugs

• These script have been tested with the OpenWrt distribution ATTITUDE ADJUSTMENT (12.09, r36088), kernel version Linux OpenWrt 3.3.8 #1 Sat Mar 23 18:09:20 UTC 2013 mips GNU/Linux on a Netgear DG834GV4 modem/router. Results may vary.
• Make sure to change the SHELL_NAME variable in the ./led.sh file to the appropriate value (echo $0 in the shell).

Resources

Leds

• https://openwrt.org/docs/guide-user/base-system/led_configuration
• https://www.kernel.org/doc/Documentation/leds/leds-class.txt

Other

• https://wiki.openwrt.org/doc/techref/initscripts

License

CC0.