#!/bin/bash
#
# goal is to do a fake dhcp request so that the dhcp server sees this mac so that DNS requests are processed
#
# Date: 2007-08-24
# Authors: Isaac Traxler, Matthew Eastman
#

for prereq in ifconfig grep cut netstat head awk dhclient
 do
    if ! type ${prereq} >/dev/null 2>&1
     then
        echo "Command '${prereq}' is required but was not found!" >&2
        exit 1
     fi
 done

# see if we're running as a script file
if [[ "${reason}" ]]
 then
    case "${reason}" in
        REBOOT)
            interface=$(netstat -nr | grep '^0' | head -n1 | awk '{print $NF}')
            curr_ip="$(ifconfig ${interface} | grep 'inet ' | cut -d':' -f2 | cut -d' ' -f1)"

            if [[ "${new_ip_address}" != "${curr_ip}" ]]
             then
                echo "WARNING! DHCP server gave us ${new_ip_address} instead of ${curr_ip}" >&2
             fi
            ;;
    esac

    exit
 fi

if pidof dhclient > /dev/null
 then
    echo "dhclient already running; doing nothing"
    exit 1
 fi

interface=$(netstat -nr | grep '^0' | head -n1 | awk '{print $NF}')
if ! dhclient -q -1 -n -sf "$0"  ${interface}
 then
    echo "Error: dhclient failed" >&2
    exit 1
 fi

killall dhclient