Updating records with dynamic dns TSIG

updatedns.pl

#!/usr/bin/perl
#
# 	This program will include a record in DNS for hosts with dynamic link. 
#
#	Author: Tácito Chaves - 2014-06-05 
#	e-mail: [email protected]
#	fone: (98) 8123-8153 / 8857-9777

use strict;
use warnings;

use LWP::Simple;

# constants
use constant {
    TMPDIR => '/tmp',
    NSFILE => '/tmp/ddns.ip'
};

# getting ip
my $ip = get_ip();

# check
if ( !-e NSFILE ) {
    open my $fh, '>', NSFILE or die "Error: $!";
    print $fh "0.0.0.0";
    close $fh;
}

my $nsfile;
open my $fhreader, NSFILE or die "Error reading: $!";
$nsfile = join( '', <$fhreader> );
chomp $nsfile;
close $fhreader;

# ip not equals
if ( $nsfile ne $ip ) {

    # ALL arises here the update of the ip
    my $keyname = "tchaves";
    my $hash ="BAb8A39m6gXtmraR1iqUkbnrBNer3vSnZ1T1+HC9djnY0RdJ0+eaYswsB9m5oMkQ56lV6DdFrI9jQ8nnz2VvkQ==";
    my $ns_server = "ns1.tchaves.com.br";
    my $zone      = "din.tchaves.com.br";
    my $host      = "teste.din.tchaves.com.br";

    # ADD register in the dns with use of pipe!	 
    open my $pipe, "| nsupdate -d " or die "Cannot open nsupdate: $!";
    print $pipe "server $ns_server\n";
    print $pipe "zone $zone\n";
    print $pipe "key $keyname $hash\n";
    print $pipe "update delete $host A\n";
    print $pipe "update add $host 60 A $ip\n";
    print $pipe "send\n";
    print $pipe "quit\n";
    close $pipe;

    # Writing information in the file	
    open my $fh, '>', NSFILE or die "Error: $!";
    print $fh "$ip";
    close $fh;

}
else {
    print "Endereço de IP não mudou!\n";
}

sub get_ip {
    my $html = get "http://meuip.datahouse.com.br";

    if ($html) {
        $html =~ m/(\d{1,3}.\d{1,3}.\d{1,3}.\d{1,3})/;
        return $1 if $1;
    }
}