#!/usr/bin/perl -w
#
# make-data
# jms1 2003-05-27
#
# Builds a tinydns "data" file from one or more input files. Some changes are
# made to the records in the input files:
# - "Z" lines are updated to use the current timestamp as the serial number.
#   Doing this guarantees that if the output is sent to multiple servers, they
#   will all have the same serial numbers in the SOA records they serve. Using
#   the unix timestamp as the serial number ensures that each run of this
#   script will produce data with higher serial numbers than the previous run,
#   so other caching nameservers will be aware of updates more quickly.
# - "." lines are converted to "Z", so that the serial numbers can be
#   controlled.
# - "3" lines are converted to ":" records containing an AAAA record.
# - "6" lines are converted to ":" records containing an AAAA record, along
#   with a "^" (PTR) line with the appropriate name. (You still need to
#   declare the appropriate "Z" and "&" records for the "xxx.ip6.arpa."
#   domain in order for tinydns to serve the records.
#
# Last updated: 2020-01-01 jms1
# - Cleaning up for public release.
# - Automatically injects a consistent serial number in all "Z" lines.
# - Converts "." lines to "Z" lines with consistent serial numbers, along
#   with "&" and "+" lines as appropriate.
# - Converts "3" and "6" to the appropriate "normal" lines.
# - Clarified that the license is GPLv2 or GPLv3, but not any unknown future
#   version of the GPL (I'm not willing to trust a license that I haven't
#   seen yet.)
#
############################################################
#
# Since https://www.fefe.de/dns/ doesn't really document the format to use
# for IPv6 records, they are:
#
#   3fqdn:addr:ttl:timestamp:lo
#   - AAAA record only
#
#   6fqdn:addr:ttl:timestamp:lo
#   - AAAA and PTR (in the "ip6.arpa." domain)
#
# In both lines, 'addr' should be exactly 32 hex digits, so the address
# '2001:db8::c0:ffee' would be written as '20010db800000000000000c0ffee'.
#
# Also, don't forget to include the appropriate "Z" and "&" lines for the
# "ip6.arpa." domain(s), otherwise tinydns won't actually serve these PTR
# records.
#
###############################################################################
#
# Copyright (C) 2003-2020 John Simpson.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 or version 3 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
# or visit http://www.gnu.org/licenses/gpl.txt
#
###############################################################################

require 5.003 ;
use strict ;

# djb's defaults for SOA records
my $ref =   16384 ; # refresh time (16384)
my $ret =    2048 ; # retry time (2048)
my $exp = 1048576 ; # expire time (1048576)
my $min =    2560 ; # minimum time (2560)

my $rcrypto = <<EOF ;
Please refer to http://cr.yp.to/djbdns/tinydns-data.html for details.
EOF

my $rfefe = <<EOF ;
Please refer to https://www.fefe.de/dns/ for details. (Need better URL.)
EOF

my $t = time ;

sub makeline(@)
{
	my $text = join ( ":" , @_ ) ;
	$text =~ s/\:+$// ;
	print "$text\n" ;
}

while ( my $line = <> )
{
	next unless ( $line =~ /[^\s]/ ) ;
	next if ( $line =~ /^#/ ) ;

    ############################################################
    # "Z" - Force the serial number to be the current timestamp.

	if ( $line =~ /^Z/ )
	{
		my @w = split ( /\:/ , $line ) ;
		$w[3] = $t ;
		$line = join ( ":" , @w ) ;
	}

    if ( $line =~ /^Z/ )
    {
        chomp $line ;
        my @w = split ( /\:/ , $line ) ;

        die "ERROR: 'Z' line missing fqdn\n$line\n$rcrypto"
                unless ( $w[0] ) ;
        die "ERROR: 'Z' line missing mname\n$line\n$rcrypto"
                unless ( $w[1] ) ;
        die "ERROR: 'Z' line missing rname\n$line\n$rcrypto"
                unless ( $w[2] ) ;

        $w[3]   = $t   ;
        $w[4] ||= $ref ;
        $w[5] ||= $ret ;
        $w[6] ||= $exp ;
        $w[7] ||= $min ;
        $line = join ( ":" , @w ) . "\n" ;
    }

    ############################################################
    # "." - Convert to "Z" and "&" lines, and possibly a "+" line if needed.
    #   Uses default values for timeouts, nameserver names, and responsible
    #   party emails. If these default values are not correct, you should
    #   change the input files and specify the "Z", "&", and maybe "+" lines
    #   the way you want them.

    if ( $line =~ s/^\.// )
    {
        chomp $line ;
        my @w = split ( /\:/ , $line ) ;
        push ( @w , "" , "" , "" , "" , "" ) ;

        die "ERROR: '.' line missing fqdn\n$line\n$rcrypto"
            unless ( $w[0] ) ;

        my $nsname = $w[2]
            ? ( ( $w[2] =~ /\./ ) ? $w[2] : "$w[2].ns.$w[0]" )
            : "ns.$w[0]" ;

        my $rname = "hostmaster.$w[0]" ;

        makeline ( "Z$w[0]" , $nsname , $rname , $t ,
            $ref , $ret , $exp , $min ,
            $w[3] , $w[4] , $w[5] ) ;

        makeline ( "&$w[0]" , $w[1] , $nsname , $w[3] , $w[4] , $w[5] ) ;

        if ( $w[1] )
        {
            makeline ( "+$nsname" , $w[1] , $w[3] , $w[4] , $w[5] ) ;
        }

        next ;
    }





	if ( $line =~ s/^\.// )
	{
		chomp $line ;
		my @w = split ( /\:/ , $line ) ;
		push ( @w , "" , "" , "" , "" , "" ) ;

		my $nsname = "ns.$w[0]" ;
		if ( $w[2] )
		{
			$nsname = ( $w[2] =~ /\./ )
				? $w[2]
				: "$w[2].ns.$w[0]" ;
		}

		my $rname = "hostmaster.$w[0]" ;

		makeline ( "Z$w[0]" , $nsname , $rname , $t ,
			$ref , $ret , $exp , $min ,
			$w[3] , $w[4] , $w[5] ) ;

		makeline ( "&$w[0]" , $w[1] , $nsname ,			
			$w[3] , $w[4] , $w[5] ) ;

		if ( $w[1] )
		{
			makeline ( "+$nsname" , $w[1] ,
				$w[3] , $w[4] , $w[5] ) ;
		}

		next ;
	}

    ############################################################
    # "3" or "6" - Convert to ":28:" line (AAAA record), and possibly add
    #   a "^" line (PTR record) in the "ip6.arpa." domain.

    if ( $line =~ s/^([36])// )
    {
        my $type = $1 ;

        chomp $line ;
        my @w = split( /\:/ , $line ) ;
        my $fqdn    = ( ( shift @w ) || '' ) ;
        my $astring = ( ( shift @w ) || '' ) ;

		die "ERROR: '$type' line missing fqdn\n$type$line\n$rfefe"
			unless ( $fqdn ) ;

        die "ERROR: '$astring' is not a valid IPv6 address string\n$type$line\n$rfefe"
            unless ( $astring =~ /^[0-9a-fA-F]{32}$/ ) ;

        ########################################
        # Build AAAA record

        my $x = $astring ;
        my $y = '' ;
        while ( $x =~ s/^(..)// )
        {
            $y .= sprintf( '\\%03o' , hex($1) ) ;
        }

        makeline( ":$fqdn" , 28 , $y , @w ) ;

        ########################################
        # Maybe build PTR record

        if ( $type eq '6' )
        {
            $y = join( '.' , reverse split( // , $astring ) ) ;

            makeline( "^$y.ip6.arpa" , $fqdn , @w ) ;
        }

        next ;
    }

	print $line ;
}