iphelper.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Management.Automation;
using System.Net;

namespace IPHelper
{
    [Cmdlet(VerbsCommon.Get,"IPList", DefaultParameterSetName = "CIDR")]
    public class GetIPList: PSCmdlet
    {
        private string cidr;
        private string startIP;
        private string endIP;

        [Parameter(Mandatory = true,
            Position = 0,
            ParameterSetName = "CIDR",
            ValueFromPipelineByPropertyName = true)]
        public string CIDR
        {
            get { return this.cidr; }
            set { cidr = value; }
        }

        [Parameter(Mandatory = true,
            Position = 0,
            ParameterSetName = "Range",
            ValueFromPipelineByPropertyName = true)]
        public string StartIP
        {
            get { return this.startIP; }
            set { startIP = value; }
        }

        [Parameter(Mandatory = true,
            Position = 1,
            ParameterSetName = "Range",
            ValueFromPipelineByPropertyName = true)]
        public string EndIP
        {
            get { return this.endIP; }
            set { endIP = value; }
        }

        protected override void ProcessRecord()
        {
            switch (ParameterSetName)
            {
                case "CIDR":
                    this.GetIPRangeByCIDR(cidr);
                    break;
                case "Range":
                    this.GetIPRange(startIP, endIP);
                    break;
                default:
                    break;
            }
        }

        protected void GetIPRange(string StartIp, string EndIp)
        {
            int start = IPToInt(StartIp);
            int end = IPToInt(EndIp);

            for (int i = start; i <= end; i++)
            {
                byte[] bytes = BitConverter.GetBytes(i);
                WriteObject(new IPAddress(new[] { bytes[3], bytes[2], bytes[1], bytes[0] }));
            }
        }

        protected void GetIPRangeByCIDR(string CIDRNet)
        {
            string[] cidr = CIDRNet.Split('/');

            // Parse values for network.
            int ip = IPToInt(cidr[0]);
            int bits = Convert.ToInt32(cidr[1]);
            int mask = ~((1 << (32 - bits)) - 1);
            int network = ip & mask;
            int broadcast = network + ~mask;
            int startIP = network + 1;
            int endIP = broadcast - 1;
            int usableIps = (bits > 30) ? 0 : (broadcast - network - 1);
           
            // Generate list
            for (int i = startIP; i <= endIP; i++)
            {
                byte[] bytes = BitConverter.GetBytes(i);
                WriteObject(new IPAddress(new[] { bytes[3], bytes[2], bytes[1], bytes[0] }));
            }
        }

        protected static int IPToInt(String IPString)
        {
            byte[] octets = IPAddress.Parse(IPString).GetAddressBytes();
            int ipint = BitConverter.ToInt32(new byte[] { octets[3], octets[2], octets[1], octets[0] }, 0);
            return ipint;
        }
    }
}