Function to determine if IP is in CIDR network?

jason_lau · ‎07-24-2016

Is there an existing script class I can use to determine if an IP address is in a given CIDR range?

Basically I want to make a call like: isInCIDR(ip_addr, cidr) and it returns true or false. I'd like to do this without first converting CIDR to range and then using SncIPRangeV4 for example.

Or as a corollary, is there a function I can call where given an IP address, it will return the IP Network (cmdb_ci_ip_network) that IP belongs to, regardless if I have that IP address mapped in CMDB.

Chuck Tomasi · ‎07-24-2016

Hi Jason,

Thanks for the inquiry. As far as I know, there's nothing OOB. It sounded like a fun thing to build on a weekend so... here's a script include you can use.

var CidrUtil = Class.create();

CidrUtil.prototype = {

   initialize: function() {

   },


   ipIsInCidr : function(ip, cidr) {

             var cidrIp = cidr.split('/')[0];

             var cidrSm = cidr.split('/')[1];


             return (this.IPnumber(ip) & this.IPmask(cidrSm)) == this.IPnumber(cidrIp);

   },


   IPnumber : function (IPaddress) {

             var ip = IPaddress.match(/^(\d+)\.(\d+)\.(\d+)\.(\d+)$/);

             if(ip) {

                       return (+ip[1]<<24) + (+ip[2]<<16) + (+ip[3]<<8) + (+ip[4]);

             }

             // else ... ?

             return null;

   },


   IPmask : function(maskSize) {

             return -1<<(32-maskSize);

   },

   type: 'CidrUtil'

};

Here's a small example how it can be used:

var ip = '192.168.1.4';

var cidr = '192.168.1.0/24';


var cu = new CidrUtil();

gs.log(cu.ipIsInCidr(ip, cidr));

View solution in original post

jonathanriehle · ‎07-16-2020

Just to add to the above script:

The IP-validation in the 'IPnumber'-function checks for digit.digit.digit.digit .

That check would work for numbers outside the legal ip range though.

E.G.: 10.1.1.1 is a valid ip and gets through. 10.300.300.300 is a non-valid-ip and passes the check as well.

Therefor to tighten the regex replace the

var ip = IPaddress.match(/^(\d+)\.(\d+)\.(\d+)\.(\d+)$/);

with

var ip = IPaddress.match(/^(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)$/);

source: https://stackoverflow.com/a/12142961

laurelin · ‎04-30-2021

Is there anything like this for ipV6?

Our business rules seem to be using an SncIPNetworkV4 library to calculate low/high addresses in a subnet if the address is v4. But nothing like this is happening for ipv6 addresses. I can find no documentation whatsoever on the various SncIP* scripts.

Thanks in advance, lauri