#!/bin/sh
#
# Copyright (c) 2012  TowardEX Technology Services Corporation
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
#       @(#)ipv6_reserve_ptr.sh  1.00 (towardEX) 5/6/2012
#

nsupdate_command=`which nsupdate`
nsupdate_flags=""

print_usage()
{
        echo 1>&2 "Usage: $0 <action> <filename>"
        echo 1>&2 "<action>:"
        echo 1>&2 "  Possible completions:"
        echo 1>&2 "    add              Add or update DNS resource record"
        echo 1>&2 "    delete           Delete DNS resource record"
        echo 1>&2 "<filename>:          Path to DNS+TSIG config input file"
}

# pre-conditional argument check
case $1 in
'add')
        ;;
'delete')
        ;;
*)
        print_usage
        exit 1
        ;;
esac

is_file_exists()
{
        if [ "$f" == "default" ]; then
                echo -n "DNS_SERVER=\"192.168.1.2\"
KEY=\"key_name\"
SECRET=\"MD5_secret_here\"
DEFAULT_TTL=\"86400\"
" > ./tsig_setup.in
        . tsig_setup.in

        elif [ -f "$f" ]; then
          . $f
        else
          echo "error: file not found, use \"default\" for default values"
          exit 1
        fi
}

# call usage() function if filename not supplied
if [ $# -eq 0 ]; then
 print_usage
 exit 1
else
 f="$2"
 is_file_exists || echo test
fi

query_user(){
        echo -n 1>&2 "Enter IPv6 host address [2001:db8::1] >> "
        read inet6_addr
        echo -n 1>&2 "Enter desired hostname (AAAA) >> "
        read _hostname
}

run_ns_update(){

std_data="server ${DNS_SERVER}\nkey ${KEY} ${SECRET}"

std_concat=`echo "inet6 $inet6_addr" | awk -v "hostname=${_hostname}" -v "action=${_action}" -v "ttl=${_ttl}" \
'! inet6 && /inet6 / && $2 !~ /^(fe80:|::1)/ {
        ip6[++j] = $2;
}
END {
  print "";
  for (j in ip6) {
        cols = gsub(/:/, ":", ip6[j]);
        zeroes = "";
        for (i = cols; i < 8; i++) {
                zeros = zeros ":0";
        }
        zeros = zeros ":";
        sub(/::/, zeros, ip6[j]);
        split(ip6[j], shorts, /:/);
        ip6str = "";
        for (i = 1; i <= 8; i++) {
                ip6str = ip6str substr("000" shorts[i],
                length(shorts[i]));
        }
        revstr = "ip6.arpa";
        for (i = 1; i <= length(ip6str); i++) {
                revstr = substr(ip6str, i, 1) "." revstr;
        }
        if ( action=="delete") 
                printf "update %s %s in ptr", action, revstr;
        else
                printf "update %s %s %s in ptr %s.",
                        action, revstr, ttl, hostname;
        print "\nsend";

        if ( action=="delete") 
                printf "update %s %s in aaaa", action, hostname;
        else
                printf "update %s %s %s in aaaa %s", action,
                        hostname, ttl, $2;
        print "\nsend";
  } 
}'`

printf "%b " "$std_concat\n"
printf "%b " "$std_data\n$std_concat\n" | "${nsupdate_command}" ${nsupdate_flags}

}
# end run_ns_update()


# main() routine
query_user

case $1 in
'add')
        _action='delete'
        _ttl=''
        run_ns_update

        _action='add'
        _ttl=${DEFAULT_TTL}
        run_ns_update
        ;;
'delete')
        _action='delete'
        _ttl=''
        run_ns_update
        ;;
*)
        exit 1
        ;;
esac

# EOF