PSLANScan

1.2.0

Get-IPs.psm1

function Get-IPs {
    [CmdletBinding(DefaultParameterSetName = "Interface")]
    Param(
        [Parameter(Mandatory = $false, ValueFromPipeline, ParameterSetName = "Interface")]
        [CimInstance[]]$NetAdapter = $null,

        [switch]$ReturnIntRange = $false
    )

    Process {

        if ($null -eq $NetAdapter) {
            Write-Verbose "IP or NetAdapter Parameters not provided, determining local networks"
            $AssignedIPs = Get-NetAdapter | ? { $_.Status -eq "up" } | Get-NetIPAddress -AddressFamily IPv4 -ErrorAction SilentlyContinue | Select IPAddress, PrefixLength
        }
        else {
            Write-Verbose "Determining networks on specified adapters"
            $AssignedIPs = $NetAdapter | Get-NetIPAddress -AddressFamily IPv4 -ErrorAction SilentlyContinue | Select IPAddress, PrefixLength
        }

        # Permit only valid LAN ranges. Avoids scanning 169.x, etc
        $AssignedIPs = $AssignedIPs | ? { $_.IPAddress -match "(^10\.)|(^172\.(1[6-9]\.|2[0-9]\.|3[0-1]\.)|(^192\.168\.))" }
    
        Write-Verbose "Found the following valid range(s)"
        $AssignedIPs | % { Write-Verbose "$($_.IPAddress.ToString())/$($_.PrefixLength.ToString())" }
    
        Write-Verbose "Enumerating possible host IPs"
        $AssignedIPs | % {
            $AllIPs = [System.Collections.ArrayList]@()

            [IPAddress]$SubnetMask = ([Math]::Pow(2, $_.PrefixLength) - 1) * [Math]::Pow(2, (32 - $_.PrefixLength))
            $FullMask = [UInt32]'0xffffffff'
            $NetworkId = [IPAddress](([IPAddress]$_.IPAddress).Address -band $SubnetMask.Address)
            $Broadcast = [IPAddress](($FullMask - $NetworkId.Address) -bxor $SubnetMask.Address)

            # Used for determining first usable IP Address
            $FirstIPByteArray = $NetworkId.GetAddressBytes()
            [Array]::Reverse($FirstIPByteArray)

            # Used for determining last usable IP Address
            $LastIPByteArray = $Broadcast.GetAddressBytes()
            [Array]::Reverse($LastIPByteArray)

            # Handler for /31, /30 CIDR prefix values, and default for all others.
            switch ($PrefixLength) {
                31 {
                    $FirstIPInt = ([IPAddress]$FirstIPByteArray).Address
                    $LastIPInt = ([IPAddress]$LastIPByteArray).Address
                    break;
                }

                32 {
                    $FirstIPInt = ([IPAddress]$FirstIPByteArray).Address
                    $LastIPInt = ([IPAddress]$LastIPByteArray).Address
                    break;
                }

                default {
                    $FirstIPInt = ([IPAddress]$FirstIPByteArray).Address + 1
                    $LastIPInt = ([IPAddress]$LastIPByteArray).Address - 1
                }
            }

            if ($ReturnIntRange -eq $true) {
                $Range = [PSCustomObject]@{
                    FirstIPInt = $FirstIPInt
                    LastIPInt  = $LastIPInt
                }
                [void]$AllIPs.Add($Range)
            }
            else {

                $CurrentIPInt = $FirstIPInt

                Do {
                    $CurrIP = [IPAddress]$CurrentIPInt
                    $CurrIP = ($CurrIP).GetAddressBytes()
                    [Array]::Reverse($CurrIP)
                    $CurrIP = ([IPAddress]$CurrIP).IPAddressToString
                    [void]$AllIPs.Add($CurrIP)
        
                    $CurrentIPInt++
        
                } While ($CurrentIPInt -le $LastIPInt)
            }
            Write-Output $AllIPs
        }
    }
}