IP address tools in Javascript

In my earlier blog I put a set of tools together for IPv4 address manipulation for sqlite,oracle and even Excel. How can I forget the simple tools needed in Javascript.  Changing IP address to long integer, subnet mask to IP address range, have all become a necessity to daily security operations people.  So here is what I have cooked up.


// first convert your IP address to long integer

function ip2long(ip) {

     var ipa=ip.split('.').reverse();

     var long=0;

     for(var i=0;i<ipa.length;i++) long=long+ipa[i]*Math.pow(2,i*8)

     return long;

}

//Coveert it back

function long2ip(long) {

  if(long < 1) return '';

  return [long >>> 24, long >>> 16 & 0xFF, long >>> 8 & 0xFF, long & 0xFF].join('.');

}

// convert a subnet like 192.168.11.24/16 to a IP integer address range or 192.168.11.0/255.255.255.0

function subnet2range(subnet) {

 var arr=subnet.split("/");

 var ip=arr[0]

 var sub=32;

 if(arr.length == 2)  {

    var match = arr[1].match(/^(\d+)\.(\d+)\.(\d+)\.(\d+)$/);

    if((match) && (match.length == 5)) 

         sub=32-Math.log(ip2long('255.255.255.255')-ip2long(arr[1])+1)/Math.LN2

    else if (parseInt(arr[1]))

         sub=parseInt(arr[1])

 }

 sub=32-sub;

 return [((ip2long(ip) >>> (sub))*Math.pow(2,sub)),((ip2long(ip) >>> (sub))*Math.pow(2,sub)+Math.pow(2,sub)-1)]

}

// convert a range to subnet back

function range2subnet(range) {

  var diff=range[1]-range[0]+1;

  var sub=32-Math.log(diff)/Math.LN2

  return long2ip(range[0])+"/"+sub

}

Let the browser do the work!