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// IP address functions
//  Author: Cory R. King (coryking@azalea.com)
//  http://www.coryking.com


// boy, wouldn't it be nice if PHP had datatypes so I can force some of this crap to be unsigned?
// wouldn't want to upset the script kiddies though....

function GetNumberOfUsable($ip_address)
{
// Inputs:
//   $ip_address - A full IP address with wither a subnet or CIDR style
//                  address (ex: 24.0.226.0/24 or 24.0.226.0/255.255.255.0)
// Returns:
//   number of avalible hosts


	$range = GetNetworkRange($ip_address);
	
	return $range - 2;  // broadcase & network

}

function GetNetworkAddress($ip_address)
{
// Inputs:
//   $ip_address - A full IP address with wither a subnet or CIDR style
//                  address (ex: 24.0.226.0/24 or 24.0.226.0/255.255.255.0)
// Returns:
//   A human readable IP address that contains the network address for the given IP


	$hex_addr = ConvertIPtoHex($ip_address);
	$subnet = Getnetmask($ip_address);
	
	$network = $hex_addr & $subnet;
	
	return ConvertHextoIP($network);

}

function GetBroadcastAddress($ip_address)
{
// Inputs:
//   $ip_address - A full IP address with wither a subnet or CIDR style
//                  address (ex: 24.0.226.0/24 or 24.0.226.0/255.255.255.0)
// Returns:
//   A human readable IP address that contains the broadcast address for the given IP


	$hex_addr = ConvertIPtoHex($ip_address);
	$subnet = Getnetmask($ip_address);
	$range = GetNetworkRange($ip_address);
	
	$broadcast = ($hex_addr & $subnet) + $range;
	
	return ConvertHextoIP($broadcast);
}

function GetNetworkRange($ip_address)
{
// Inputs:
//   $ip_address - A full IP address with wither a subnet or CIDR style
//                  address (ex: 24.0.226.0/24 or 24.0.226.0/255.255.255.0)
// Returns:
// this function is the opposite of the netmask function
// it returns the range of usable addresses in hex/dec format

	$mask = GetNetmask($ip_address);
	
	return (-1 - $mask);
	
}


function GetNetmask($ip_address)
{
// Inputs:
//   $ip_address - A full IP address with wither a subnet or CIDR style
//                  address (ex: 24.0.226.0/24 or 24.0.226.0/255.255.255.0)
// Returns:
//  returns a hex/dec representation of the net mask for the given IP


	// first we need to split the ip up
	$ip_parts = preg_split("/[\.\/]/", $ip_address);

	// how big are we, did this guy give us a subnet mask, or
	// a cidr style address?

	if(Count($ip_parts)==8)
	{
		// we have a subnet
		$netmask_hex  = $ip_parts[7];
		$netmask_hex += $ip_parts[6] << 8;
		$netmask_hex += $ip_parts[5] << 16;
		$netmask_hex += $ip_parts[4] << 24;
	}

	if(Count($ip_parts)==5)
	{
		// we have a CIDR style adddress, first get the address
		$netmask_hex = 0xFFFFFFFF >> ($ip_parts[4] - 1);

	}

	if(Count($ip_parts)==4)
	{
		// just an IP
		$netmask_hex = -1;
	}

	return $netmask_hex;

}


function ConvertIPtoHex($ip_address)
{
// Inputs:
//   $ip_address - A full IP address with wither a subnet or CIDR style
//                  address (ex: 24.0.226.0/24 or 24.0.226.0/255.255.255.0)
// Returns:
//   a decimal/hex representation of the given IP (strips out the subnet stuff)


	// first we need to split the ip up
	$ip_parts = preg_split("/[\.\/]/", $ip_address);

	// now we get the number...
	$ip_hex  = $ip_parts[3];
	$ip_hex += $ip_parts[2] << 8;
	$ip_hex += $ip_parts[1] << 16;
	$ip_hex += $ip_parts[0] << 24;

	return $ip_hex;

}

function ConvertHextoIP($hex_address)
{

	// takes a hex address and converts it into a human readable IP address

	// I'm going to shift, then mask as it appears that php has some kind
	// of bug when i do it the other way.
	// I think it's because of a of a sign thing (they probably use a 4 byte signed int)
	// damn typeless languages... damn script kiddies.. "oooo data types.
	// I don't know no data types, thats not in the sams teach your self php in 24 hours book".
	// Course, if you're one of those script kiddies
	// then this probably doesn't make much sense either...
	
	$ip_hex[0] = $hex_address & 0xFF;   
	$ip_hex[1] = ($hex_address >> 8) & 0xFF;
	$ip_hex[2] = ($hex_address >> 16) & 0xFF;
	$ip_hex[3] = ($hex_address >> 24) & 0xFF;

	$ip_text = "$ip_hex[3].$ip_hex[2].$ip_hex[1].$ip_hex[0]";
	
	return $ip_text;
}


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