#!/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  1.10 (towardEX) 5/6/2012
#

HOSTNAME_PREFIX="-1"
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 "./__ipv6_to_base36.sh" ]; then
          echo "error: __ipv6_to_base36.sh not loaded, run script from local directory!"
          exit
        fi
        if [ "$f" == "default" ]; then
                echo -n "DNS_SERVER=\"192.168.1.2\"
KEY=\"key_name\"
SECRET=\"MD5_secret_here\"
DEFAULT_TTL=\"86400\"
#HOSTNAME_PREFIX=\"hcctrc.com\"
" > ./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 "CC
IPv4-mapped in IPV6, Dual-Stack Addressing Trick Method:
  2001:db8:2ff::10.23.17.2 becomes:

  2001:db8:2ff::0a17:1102
  "

        echo -n 1>&2 "Enter IPv6 base prefix, terminate with ::, NO Pfx Len! Example: [2001:db8:2ff::] >> "
        read inet6_base

        echo -n 1>&2 "Enter IPv4 host address [10.23.0.2] >> "
        read ipv4_host

        _hexconv=`sh ./__ipv4_to_hex.sh ${ipv4_host}`
        inet6_addr="${inet6_base}${_hexconv}"

        echo "

This is the converted IPv6 address, is this OK?

   [${inet6_addr}]

If NOT OK, Ctrl-C to abort NOW!  Press [CR]/Enter to continue..
"
read junk

echo "
---------------------------------------------------------------
"

        if [ ${HOSTNAME_PREFIX} != -1 ]; then
           echo -n 1>&2 "HOSTNAME.ptn loaded, enter domain suffix [onesummer.ma.sys.tcisn.net] >> "
           read _domain_sfx
           _base36=`sh ./__ipv6_to_base36.sh ${inet6_addr}`
           _hostname="${HOSTNAME_PREFIX}${_base36}.${_domain_sfx}"
           echo -n 1>&2 "auto-gen: [$_hostname]"
        else

        _hostname=`host ${ipv4_host} | awk '{ print $NF }'`

        echo "

This is what I have for desired hostname mapping.  Is this OK?

   [${_hostname}]

If NOT OK, Ctrl-C to abort NOW!  If you want to enter your own hostname,
use the 'ipv6-reverse-ptr.sh' for manual operation.

Press [CR]/Enter to continue..
"
read junk

        fi
}

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";

  } 
}'`

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