#!/usr/bin/perl
#
# This code is for use in conjunction with adding NAT's to supernat
#
# Example usage:
#
# my $addr = "10.47.3.24";
#
# if (Pos::Webtop::Supernat::supernatIsIpInsideCompanyIntranet(db => $db, companyId => 16, actualAddress => $addr)) {
# 		$addr = Pos::Webtop::Supernat::supernatGetInternalAddress(
#					supernatIp    => '127.0.0.1',
#					supernatPort  => 7654,
#					companyId     => 16,
#					requestType   => 'WEB_SESSION',
#					requestTypeId => '1',
#					actualAddress => '192.168.0.1');
# }
# 
# This will use the supernat server running on 127.0.0.1:7654.
# It will request that a NAT for the actual address of '192.168.0.1' be created using companyId 16 and the NAT
# that is created should be correlated with Id 1 of WEB_SESSION.
# 
# On success, a dotted quad ip address is returned that is the address that should be used internally, otherwise undef is returned.
#

package Pos::Webtop::Supernat;

use strict;
use Socket;
use IO::Socket;
use IO::Socket::INET;
use IO::Select;

sub supernatIsIpInsideCompanyIntranet {
	my ($db, $companyId, $actualAddress) = @{{@_}}{qw/db companyId actualAddress/};
	my $ret = 0;

	my @subnets = $db->query(sql => "
			select
				RAWIP32_TO_DOTTED_QUAD_NO(subnet) as SUBNET,
				RAWIP32_TO_DOTTED_QUAD_NO(netmask) as NETMASK
			from
				customer_subnets
			where
				customer_id = '" . $db->escape(dirty => $companyId) . "'
			union
			select
				RAWIP32_TO_DOTTED_QUAD(
					coalesce(virtual_destination, destination_network)) as SUBNET,
				RAWIP32_TO_DOTTED_QUAD(destination_netmask) as NETMASK
			from
				customer_partner_resources
			where
				customer_id = '" . $db->escape(dirty => $companyId) . "'
			");

	my $actualLong  = unpack("L", inet_aton($actualAddress));

	foreach my $subneta (@subnets) {
		my ($subnet, $netmask) = @{ $subneta };

		my $subnetLong  = unpack("L", inet_aton($subnet));
		my $netmaskLong = unpack("L", inet_aton($netmask));

		if (($actualLong & $netmaskLong) == ($subnetLong & $netmaskLong)) {
			$ret = 1;

			last;
		}
	}

	return $ret;
}

sub supernatGetInternalAddress {
	my ($supernatIp, $supernatPort, $companyId, $requestType, $requestTypeId, $actualAddress, $requestor) = @{{@_}}{qw/supernatIp supernatPort companyId requestType requestTypeId actualAddress requestor/};
	
	my $connection = IO::Socket::INET->new(
			PeerAddr => $supernatIp,
			PeerPort => $supernatPort,
			Proto    => 'tcp') or return undef;
								
	$|=1;

	my $networkByteAddr = unpack("L", inet_aton($actualAddress));

	my $cmd = "$companyId;$requestType;$requestTypeId;$networkByteAddr";

	# If a requestor is specified, we pass it along.  THis allows us to setup supernats on behalf of another.
	if (defined($requestor)) {
		my $networkReq = unpack("L", inet_aton($requestor));

		$cmd .= ";$networkReq";
	}

	$cmd .= "\n";

	syswrite($connection, $cmd);

	$connection->flush();
	
	my $s = IO::Select->new($connection);
	my @ready = $s->can_read(15);
	
	if (not defined($ready[0])) { return undef; }
	
	# we read only first line, other lines have additional information we do not need
	my $data = <$connection>;
	chomp $data;

	my $packed = pack("L", $data);

	return inet_ntoa($packed);
}

# db passed here must be same db that supernatd on supernat boxes
# is working with.  This is typically the webtop db writer.
# WARNING using this will cause a commit on the db.
sub supernatReleaseDynamicBackendNat
{
	my ($db,$companyId,$actualAddress) = @{{@_}}{qw/db companyId actualAddress/};
	my $ret = 0;

	my @sninfo = $db->query( sql=> "
		select supernat_nat_id, \"references\" from supernat_ns_nats where customer_id = '" . $db->escape( dirty=> $companyId ) . "'
			and rawip32_to_dotted_quad_no(customer_internal_addr) = '" . $db->escape( dirty=> $actualAddress ) . "'
		for update
	");

	if ( not @sninfo )
	{
		warn "Could not release backend dynamic nat because requested actualAddress was not found in nat database!\n";
		return undef;
	}
	
	my ($supernatNatId,$backendDynamicReferences) = @{ $sninfo[0] };
	
	if ( (defined $supernatNatId) and ($backendDynamicReferences > 0) )
	{
		$backendDynamicReferences--;

		$db->do( sql=> "
			update supernat_ns_nats set \"references\" = $backendDynamicReferences
			where supernat_nat_id = $supernatNatId
		");
	}

	$db->commit();
}		

1;