#!/bin/bash

##########
# File: pump.script
# Author: Cody Casterline <cody.casterline@technologist.com>
#
# This script makes pump run the dhcpcd-<device>.exe script when 
# the DHCP-assigned IP changes.
# 
# Note: You'll need a line like this in your pump.conf file:
# script /full/path/to/pump.script
##########



# Set SCRIPTDIR to the location of your dhcpcd-<device>.exe scripts.
SCRIPTDIR="/etc/dhcpc";


# Arguments passed by pump:
# arg1 = up/renewal/down
ACTION=$1;
# arg2 = device (ex: eth0)
DEVICE=$2;
# arg3 = IP address
IPADDR=$3;



# IPs only change when the DHCP lease is brought up or renewed.
if [[ ($ACTION != "up") && ($ACTION != "renewal") ]];
then { exit; }
fi;


# Also, make sure there's a script to run:
scriptname="$SCRIPTDIR/dhcpcd-$DEVICE.exe";
if [[ !(-x $scriptname) ]];
then exit;
fi;

# Make sure the IP has actually changed:

cachefile="$SCRIPTDIR/pump.$DEVICE.lastip";
if [[ -e $cachefile ]];
then
	OLDIP=`cat $cachefile`;
	if [[ $OLDIP == $IPADDR ]]; then exit; fi; # IP hasn't changed, exit.
fi;

# Ok, we know now the IP has changed, and our script exists.  
# Let's update our cache, and call the script!

echo -n $IPADDR > $cachefile;
exec $scriptname