#!/usr/bin/perl

use strict;
use warnings;
use Net::DNS;
use NetAddr::IP;
  use Time::HiRes qw( usleep ualarm gettimeofday tv_interval nanosleep
                      clock_gettime clock_getres clock_nanosleep clock
                      stat );use DBI;
use Math::Round;
my $current_range = 0;
$SIG{'INT'} = 'CLEANUP';
$SIG{'TERM'} = 'CLEANUP';
sub CLEANUP {
        print "Caught SIGTERM, marking range $current_range as 
stopped\n";
        if ($current_range != 0) {
                my $dsn = 'DBI:mysql:reverse_dns:localhost';
                my $db_user_name = 'db user';
                my $db_password = 'password';
                my ($id, $password);
                my $dbh = DBI->connect($dsn, $db_user_name, 
$db_password) or die("Cannot connect to database");
                $dbh->do(qq{update `ranges` set status = 2 ,start_time = 
0,session=0 where id = $current_range});
        }
        exit(1);
}


# now connect to the DB

my $dsn = 'DBI:mysql:reverse_dns:localhost';
my $db_user_name = 'db user';
my $db_password = 'none of your business';
my $dbh = DBI->connect($dsn, $db_user_name, $db_password) 
	or die("Cannot connect to database");

# get the IP ranges to work on
my $query1 = $dbh->prepare('select * from ranges where status = 0 OR status = 2 order by status desc limit 1');
$query1->execute(
while (my @ranges = $query1->fetchrow_array()) {
	my $range_id = $ranges[0];
	$current_range = $range_id;
	my $ip = new NetAddr::IP ($ranges[1].'/'.$ranges[2]) + 
		($ranges[4] +1)  
		or die "Unable to create IP object\n"; # $ranges[4] is the previous offset
	my $res = Net::DNS::Resolver->new;
	my $num = $ip->num();
	$res->tcp_timeout(10);
	$dbh->do(qq{
		update ranges set status = 1, start_time = 
		UNIX_TIMESTAMP() where id = $range_id}) 
	or die("Can't set a range to in progress");
	my $success = 0;
	my $errors = 0;
	print "Starting at ".$ip->addr()."\n";
	my $session = 0;
	for (my $i=$ranges[4]; $i<=$num; ++$i) {
		my $ip_address = $ip->addr();
		if ($ip_address) {
                	my $query = $res->search("$ip_address");
                	if ($query) {
				foreach my $rr ($query->answer) {
					next unless $rr->type eq "PTR";
					my $hostname = $rr->ptrdname;
                                	$dbh->do(
                                	qq{
                	insert into entries (ip,hostname,time,range_id)
			values(INET_ATON('$ip_address'),"$hostname",NOW(),$range_id) });
                			$success++;
                        		}
                	} else {
                        	$errors++;
                	}
        	$dbh->do(qq{update ranges set offset = $i,session=$session where id = $range_id});
        	$session++;
  	}

        if ($i % 100 == 0) {
        print $ranges[1].'/'.$ranges[2]." ".int((($i/$num)*100))."% 
Processed $i of $num IPs, Sucessful $success, Failed $errors\n";
       }
  ++$ip;
        usleep(25); # to stop it overloading the nameserver!
}

$dbh->do(qq{update ranges set status=3,start_time=0,session=0 where id = 
$range_id}) or
die("Can't set a range to done");
}
print "Pass complete!\n";