IP 주소 서브넷 마스크 계산

IP地址子网掩码计算，返回IP段起止范围、长度、掩码等信息。

/**
 * 掩码计算器
 * @author WeakSun <52132522@qq.com>
 * @param string $ip IP
 * @param numeric $bits 掩码
 * @return array 返回结果集
 */
function netmask($ip, $bits = 24) {
	$result = [
		'start' => 0, //第一个IP
		'end' => 0, //最后一个IP
		'length' => 0, //包含的IP个数
		'netmask' => (~pow(2, 32 - $bits))   1, //子网掩码
		'networkSegment' => 0, //IP段
		'bcast' => 0//广播地址
	];
	$result['length'] = abs($result['netmask']) - 2;
	$result['networkSegment'] = ip2long($ip) & $result['netmask'];
	$result['start'] = $result['networkSegment']   1;
	$result['end'] = $result['networkSegment']   $result['length'];
	$result['bcast'] = $result['end']   1;
	return $result;
}

list($ip, $bits) = explode('/', '192.168.1.5/25');
$tmpArr = netmask($ip, $bits);
foreach ($tmpArr as $k => &$v) {
	$k != 'length' && $v = long2ip($v);
}
echo '' . var_export($tmpArr, true).'';

array (</li>
<li>  'start' => '192.168.1.1',</li>
<li>  'end' => '192.168.1.126',</li>
<li>  'length' => 126,</li>
<li>  'netmask' => '255.255.255.128',</li>
<li>  'networkSegment' => '192.168.1.0',</li>
<li>  'bcast' => '192.168.1.127',</li>
<li>)

서브넷 마스크