#!/usr/bin/env perl
# License: 3-Clause BSD. Author: Matthew Connelly.
# This is a (formerly Bash, now Perl) script for managing in-addr.arpa and ip6.arpa zones.
# If you have any questions or issues, open an issue at https://bitbucket.org/MaffC/script-collection/issues

use strict;
use warnings;

package DNS::Reverse::Manager;

use Data::Validate::Domain qw(is_domain);                            #for validating domains
use Data::Validate::IP qw(is_public_ipv4 is_public_ipv6);            #for validating v4/v6 addresses
use Getopt::Long qw(:config posix_default bundling pass_through);    #for intelligently handling cli arguments
use Net::DNS;                                                        #for doing forward and reverse lookups
use Net::IP;                                                         #for converting IPs to their reverse zones
use Data::Dumper;

#conf
my $def_rdns = 'hosted-by.mycompany.com';
my $def_dns = '8.8.8.8';

#variables for arguments
our $verify = '';
our $force = '';
our $reset = '';
our $nosync = '';
our $fsync = '';
our $delptr = '';
our $newzone = '';
our $prefixlen = 64;

#functions
sub nicedie {
	print shift."\n";
	exit 1;
}
sub validate_domain {
	my $domain = shift;
	return 1 if is_domain $domain;
	return 0;
}
sub validate_ip {
	my $ip = shift;
	return 1 if is_public_ipv4($ip) || is_public_ipv6($ip);
	return 0;
}
sub get_arpa {
	my $ip = shift;
	if(is_public_ipv4 $ip) {
		$ip =~ m/^([0-9]+)\.([0-9]+)\.([0-9]+)\.([0-9]+)$/;
		return ($4, "$3.$2.$1.in-addr.arpa");
	}
	my $len = ($prefixlen/2);
	Net::IP->new($ip)->reverse_ip =~ /^(.*)\.(.{$len}ip6\.arpa)\.$/;
	return ($1,$2);
}
#TODO make these work for DNS roundrobins. I doubt anyone would be stupid enough to have more than one PTR of the same name
# and i'm not sure if it's even legal, but hey.
sub does_fqdn_match {
	my ($fqdn,$ip) = @_;
	my $r = Net::DNS::Resolver->new(recurse => 1);
	my $p = $r->search($fqdn, 'A');
	$p = $r->search($fqdn, 'AAAA') unless is_public_ipv4 $ip;
	return 0 unless defined $p;
	my @res = $p->answer;
	#due to IPv6 shortening, we need to use Net::IP here
	return 1 unless scalar @res < 1 || Net::IP->new($res[0]->address)->ip ne Net::IP->new($ip)->ip;
	return 0;
}
sub confirm_rdns {
	my ($fqdn,$ip) = @_;
	my ($rec,$zone) = get_arpa $ip;
	my $rrec = $rec.".".$zone;
	my $r = Net::DNS::Resolver->new(recurse => 1,tcp_timeout => 5,udp_timeout => 5);
	my $p = $r->search($rrec, 'PTR');
	return 0 unless defined $p;
	my @res = $p->answer;
	return 1 unless scalar @res < 1 || $res[0]->ptrdname."." ne $fqdn;
	return 0;
}
sub get_rdns {
	my $ip = shift;
	return "";
}
sub set_rdns {
	my $ip = shift;
	my $fqdn = shift;
	my ($record,$zone) = get_arpa $ip;
	return 1;
}
sub generate_zone {
	my ($rec,$zone) = get_arpa shift;
	return 1;
}
sub sync_cpanel {
	return 1;
}

#main
#do argument parsing. all unknown arguments get left in @ARGV so I can `shift`.
GetOptions
	'reset-hostname=s'	=>	\$def_rdns,
	'dns-server=s'		=>	\$def_dns,
	'v|verify-rdns'		=>	\$verify,
	'f|force'			=>	\$force,
	'r|reset'			=>	\$reset,
	'p|populate'		=>	\$newzone,
	'd|no-sync'			=>	\$nosync,
	's|force-sync'		=>	\$fsync,
	'R|remove-ptr'		=>	\$delptr;

#get IP and domain, validate.
my $ip = shift or nicedie "No IP given!";
$prefixlen = $1 if $ip =~ s/\/([0-9]+)//; #split off prefixlen (if given) into variable for later use
nicedie "Invalid IP address '$ip'!" unless validate_ip $ip;
my $domain = shift or nicedie "No FQDN given!" unless $fsync || $reset || $delptr; #conditionally allow the user to not specify a fqdn
nicedie "Invalid FQDN '$domain'!" if defined $domain && !validate_domain $domain;
$domain =~ s/([a-zA-Z])$/$1./; #Append final period if it doesn't exist

#main flow