use strict;
use Socket;
my $hostname = `hostname`;
$hostname=strip($hostname);
my $ip_address='';
my ($name,$aliases,$addrtype,$length,@addrs)=gethostbyname($hostname);
foreach my $ip_addr (@addrs){
     my @tmp = unpack('C4',$ip_addr);
     $ip_address=join('.',@tmp);
     next if $ip_address=~/^169\.254/s;
     print "checking $ip_address\n";
	my ($sock,$err) = connectToHost("www.google.com",80,$ip_addr);
	if(!$err){last;}
	}
print "IP Address with gateway to internet: $ip_address\n";
exit;
##################
sub connectToHost {
	# Create a socket that connects to a certain host
	# connectToHost($MainSock, $remote_hostname, $port)
	my ($remote_hostname, $port,$ip_addr) = @_;
	my $Sock;
	#print "connectToHost ($remote_hostname, $port)\n";
	my ($socket_format, $proto, $packed_port, $cur);
	my ($remote_addr, @remote_ip, $remote_ip);
	my ($local_port, $remote_port);
	if ($port !~ /^\d+$/) {
		$port = (getservbyname($port, "tcp"))[2];
		$port = 80 unless ($port);
		}
	$proto = (getprotobyname('tcp'))[2];
	$remote_addr = (gethostbyname($remote_hostname))[4];
	if (!$remote_addr) {
		return (undef,"Unknown host: $remote_hostname");
		}
	@remote_ip = unpack("C4", $remote_addr);
	$remote_ip = join(".", @remote_ip);
	#print STDOUT "Connecting to $remote_ip port $port.\r\n";
	$socket_format = 'S n a4 x8';
	$local_port = pack($socket_format, &AF_INET, 0, $ip_addr);
	$remote_port = pack($socket_format, &AF_INET, $port, $remote_addr);
	socket($Sock, &AF_INET, &SOCK_STREAM, $proto) || return (undef,"Socket Error: $!");
	bind($Sock, $local_port) || return (undef,"Socket Bind Error: $!");
	#print "connect($Sock, $remote_port)\n";
	connect($Sock, $remote_port) || return (undef,"Socket Connect Error: $!");
	$cur = select($Sock);
	$| = 1; # Disable buffering on socket.
	select($cur);
	return $Sock;
	}
###############
sub strip{
	#usage: $str=strip($str);
	#info: strips off beginning and endings returns, newlines, tabs, and spaces
	my $str=shift;
	if(length($str)==0){return;}
	$str=~s/^[\r\n\s\t]+//s;
	$str=~s/[\r\n\s\t]+$//s;
	return $str;
	}
exit;