#!/bin/sh
#
# This is a shell script for performing TSIG-signed dynamic DNS updates
# using "nsupdate". It needs BIND 9.2.2 or later
#
# All updates are in the form of a single "A" resource record, which needs
# a domain name and its IP address
#
# You need to provide five parameters to invoke this shell script
#
# $1: TSIG key and secret in the form of key:secret
# $2: operation string: either "add" or "delete"
# $3: The hostname (FQDN) to be updated
# $4: The IP address for the updated hostname
# $5: the DNS server for sending updates (can be NULL). To improve
#     performance, you should provide this parameter
#
# (c) Columbia University, 2004-2006, All Rights Reserved.
# Author: Weibin Zhao
#


bind_bin=/home/zwb/data1/bind/bin

if [ $# -ne 5 ]
then
    echo "Usage: $0 key:secret update_opstr host_name ip_address dns_server"
    exit -1
fi

if [ $2 != "add" -a $2 != "delete" ]
then
    echo "update_operation_string must be either add or delete"
    exit -1
fi

set_server=""
if [ $5 != "NULL" ]
then
set_server="server $5"
fi

if [ $2 = "add" ]
then
${bind_bin}/nsupdate -y $1 <<-EOF
${set_server}
update add $3 1800 in A $4
send
EOF
elif [ $2 = "delete" ]
then
${bind_bin}/nsupdate -y $1 <<-EOF
${set_server}
update delete $3 A $4
send
EOF
fi