Table of Contents

Auto Wake On LAN script for hosts

At the very least, users should consider putting the LOGFILE on /tmp/ rather than on flash. OpenWrt also does not serve HTML pages in the same way as DD-WRT.

Note also problems with rebooting a router running this script described at https://forum.openwrt.org/t/cant-reboot-while-sleep-script-wol/

Hi guys, I found on https://www.dd-wrt.com/wiki/index.php/Useful_Scripts#Web_Server_Wake-up this useful script for wake up a host by request.
I use it to wake up my NAS if my Kodi or PC want anything from it.

Requirements:

Script settings

Required to change Variables Default value Description
optional INTERVAL 5 repeat the script every N second
not required OLD empty should be empty
optional PORT 80 it the port who looks the script
optional NUMP 3 the retries, before the script gave up
yes TARGET 192.168.1.1 the wake up device
yes INTERFACE br-lan here you can type in a broadcast address or a interface, i like more interface
yes MAC 00:00:00:00:00:00 the target mac adress
not required WOL /usr/bin/etherwake the program and path for wol
optional LOGFILE “/www/wol/index.html” the log output folder, in this case for the url <ROUTER-IP>/wol/index.html
optional LOGPROG “logread” i will read the logs from LOGREAD, but you can also read from “dmesg” or something else

Instructions

1. Preparation

Install the required packages. 

opkg update
opkg install etherwake

2. Auto WoL script

Saving the script. 

cat << "EOF" > /bin/autowol.sh
#!/bin/sh
#Enable JFFS2 and place script in /jffs/ then run on startup in web interface.
#You can check the log from http://192.168.1.1/user/wol.html
 
#debugging
#set -xv
 
INTERVAL=5
NUMP=3
OLD=""
PORT=80
TARGET=192.168.1.1
INTERFACE=br-lan
MAC=00:00:00:00:00:00
WOL=/usr/bin/etherwake
LOGFILE="/www/wol/index.html"
LOGPROG="logread" # default: dmesg
 
echo "<meta http-equiv=\"refresh\" content=\"10\">" > $LOGFILE
echo "AUTO WOL Script started at" `date` "<br>" >> $LOGFILE
 
wake_up () {
	PORT=$1
	TARGET=$2
	BROADCAST=$3
	MAC=$4
	NEW=`$LOGPROG | awk '/WOL_LOG/ && /DST='"$TARGET"'/ && /DPT='"$PORT"'/ {print }' | tail -1`
	SRC=`$LOGPROG | awk -F'[=| ]' '/WOL_LOG/ && /DST='"$TARGET"'/ && /DPT='"$PORT"'/ {print }' | tail -1`
	LINE=`$LOGPROG | awk '/WOL_LOG/ && /DST='"$TARGET"'/ && /DPT='"$PORT"'/'`
	if [ "$NEW" != "" -a "$NEW" != "$OLD" ]; then
		if ping -qc $NUMP $TARGET >/dev/null; then
			echo "NOWAKE $TARGET was accessed by $SRC and is already alive at" `date` "<br>">> $LOGFILE
		else
			echo "WAKE $SRC causes wake on lan at" `date` "<br>">> $LOGFILE
			$WOL -i $BROADCAST $MAC >> $LOGFILE
			echo "<br>" >> $LOGFILE
			sleep 5
		fi
		OLD=$NEW
	fi
}
 
while sleep $INTERVAL; do
wake_up $PORT $TARGET $INTERFACE $MAC;
done
EOF
chmod +x /bin/autowol.sh

Pro Tip: Don't copy the code above as it causes a bunch of errors due to a stray CRLF character at the end of each line. Instead just download a copy of the file here, and save yourself a day of troubleshooting!

3. Autostart

First autostart, if the script is ok.

Go to System → Startup → Local Startup and type in: 

/bin/autowol.sh

Troubleshooting

Enable debug output: 

sh -x -v /bin/autowol.sh

Check the log file: http://192.168.1.1/wol/

Go to Network → Firewall → Custom Rules and add this rule: 

iptables -I FORWARD 1 -p tcp -d 192.168.1.1 -m limit --limit 1/min -j LOG --log-prefix "WOL_LOG:  " --log-level 7