# Subnet Math functions
#
# Author: Chris Dent
# Date: 23/01/2010

# How to run these:
# Either: Copy and Paste everything here into the PowerShell Prompt
# Or:     Save this as .ps1.
#           Run:
#             . .\Net-SubnetMath.ps1
#             . C:\WhereverYouPutIt\Net-SubnetMath.ps1
#
# The leading dot makes these available in the current shell 
# rather than just the script. See Dot Source in:
# http://technet.microsoft.com/en-us/library/ee176949.aspx
# 
# Usage examples are at the bottom of this file

Function ConvertTo-BinaryIP( [String]$IP ) {

  $IPAddress = [Net.IPAddress]::Parse($IP)

  Return [String]::Join('.', 
    $( $IPAddress.GetAddressBytes() | %{ 
      [Convert]::ToString($_, 2).PadLeft(8, '0') } ))
}

Function ConvertTo-DecimalIP( [String]$IP ) {

  $IPAddress = [Net.IPAddress]::Parse($IP)
  $i = 3; $DecimalIP = 0;
  $IPAddress.GetAddressBytes() | %{
    $DecimalIP += $_ * [Math]::Pow(256, $i); $i-- }

  Return [UInt32]$DecimalIP
}

Function ConvertTo-DottedDecimalIP( [String]$IP ) {

  Switch -RegEx ($IP) {
    "([01]{8}\.){3}[01]{8}" {

      Return [String]::Join('.', $( $IP.Split('.') | %{ 
        [Convert]::ToInt32($_, 2) } ))
    }
    "\d" {

      $IP = [UInt32]$IP
      $DottedIP = $( For ($i = 3; $i -gt -1; $i--) {
        $Remainder = $IP % [Math]::Pow(256, $i)
        ($IP - $Remainder) / [Math]::Pow(256, $i)
        $IP = $Remainder
       } )
       
      Return [String]::Join('.', $DottedIP)
    }
    default {
      Write-Error "Cannot convert this format"
    }
  }
}

Function ConvertTo-MaskLength( [String]$Mask ) {

  $IPMask = [Net.IPAddress]::Parse($Mask)
  $Bits = "$( $IPMask.GetAddressBytes() | %{
    [Convert]::ToString($_, 2) } )" -Replace "[\s0]"

  Return $Bits.Length
}

Function ConvertTo-Mask( [Byte]$MaskLength ) {

  Return ConvertTo-DottedDecimalIP ([Convert]::ToUInt32(
    $(("1" * $MaskLength).PadRight(32, "0")), 2))
}

Function Get-NetworkAddress( [String]$IP, [String]$Mask ) {

  Return ConvertTo-DottedDecimalIP $(
    (ConvertTo-DecimalIP $IP) -BAnd 
    (ConvertTo-DecimalIP $Mask))
}

Function Get-BroadcastAddress( [String]$IP, [String]$Mask ) {

  Return ConvertTo-DottedDecimalIP $(
    (ConvertTo-DecimalIP $IP) -BOr 
    ((-BNot (ConvertTo-DecimalIP $Mask)) -BAnd [UInt32]::MaxValue))
}

Function Get-NetworkInfo( [String]$IP, [String]$Mask ) {
  If ($IP.Contains("/"))
  {
    $Temp = $IP.Split("/")
    $IP = $Temp[0]
    $Mask = $Temp[1]
  }

  If (!$Mask.Contains("."))
  {
    $Mask = ConvertTo-Mask $Mask
  }

  $DecimalIP = ConvertTo-DecimalIP $IP
  $DecimalMask = ConvertTo-DecimalIP $Mask
  
  $Network = $DecimalIP -BAnd $DecimalMask
  $Broadcast = $DecimalIP -BOr 
    ((-BNot $DecimalMask) -BAnd [UInt32]::MaxValue)
  $NetworkAddress = ConvertTo-DottedDecimalIP $Network
  $RangeStart = ConvertTo-DottedDecimalIP ($Network + 1)
  $RangeEnd = ConvertTo-DottedDecimalIP ($Broadcast - 1)
  $BroadcastAddress = ConvertTo-DottedDecimalIP $Broadcast
  $MaskLength = ConvertTo-MaskLength $Mask
  
  $BinaryIP = ConvertTo-BinaryIP $IP; $Private = $False
  Switch -RegEx ($BinaryIP)
  {
    "^1111"  { $Class = "E"; $SubnetBitMap = "1111" }
    "^1110"  { $Class = "D"; $SubnetBitMap = "1110" }
    "^110"   { 
      $Class = "C"
      If ($BinaryIP -Match "^11000000.10101000") { $Private = $True } }
    "^10"    { 
      $Class = "B"
      If ($BinaryIP -Match "^10101100.0001") { $Private = $True } }
    "^0"     { 
      $Class = "A" 
      If ($BinaryIP -Match "^00001010") { $Private = $True } }
   }   
   
  $NetInfo = New-Object Object
  Add-Member NoteProperty "Network" -Input $NetInfo -Value $NetworkAddress
  Add-Member NoteProperty "Broadcast" -Input $NetInfo -Value $BroadcastAddress
  Add-Member NoteProperty "Range" -Input $NetInfo `
    -Value "$RangeStart - $RangeEnd"
  Add-Member NoteProperty "Mask" -Input $NetInfo -Value $Mask
  Add-Member NoteProperty "MaskLength" -Input $NetInfo -Value $MaskLength
  Add-Member NoteProperty "Hosts" -Input $NetInfo `
    -Value $($Broadcast - $Network - 1)
  Add-Member NoteProperty "Class" -Input $NetInfo -Value $Class
  Add-Member NoteProperty "IsPrivate" -Input $NetInfo -Value $Private
  
  Return $NetInfo
}

Function Get-NetworkRange( [String]$IP, [String]$Mask ) {
  If ($IP.Contains("/"))
  {
    $Temp = $IP.Split("/")
    $IP = $Temp[0]
    $Mask = $Temp[1]
  }

  If (!$Mask.Contains("."))
  {
    $Mask = ConvertTo-Mask $Mask
  }

  $DecimalIP = ConvertTo-DecimalIP $IP
  $DecimalMask = ConvertTo-DecimalIP $Mask
  
  $Network = $DecimalIP -BAnd $DecimalMask
  $Broadcast = $DecimalIP -BOr ((-BNot $DecimalMask) -BAnd [UInt32]::MaxValue)

  For ($i = $($Network + 1); $i -lt $Broadcast; $i++) {
    ConvertTo-DottedDecimalIP $i
  }
}

#
# Examples
#

Function RunExample( $Expression )
{
  Write-Host "Running: $Expression" -ForegroundColor Green
  Invoke-Expression $Expression
}

RunExample "ConvertTo-BinaryIP 192.168.1.1"
RunExample "ConvertTo-DecimalIP 192.168.1.1"
RunExample "ConvertTo-DottedDecimalIP 11000000.10101000.00000001.00000001"
RunExample "ConvertTo-DottedDecimalIP 3232235777"
RunExample "ConvertTo-MaskLength 255.255.128.0"
RunExample "ConvertTo-Mask 17"

RunExample "Get-NetworkAddress 192.168.1.1 255.255.255.0"
RunExample "Get-BroadcastAddress 192.168.1.1 255.255.255.0"

RunExample "Get-NetworkInfo 229.168.1.1 255.255.248.0"
RunExample "Get-NetworkInfo 172.16.1.243 18"
RunExample "Get-NetworkInfo 10.0.0.3/14"

RunExample "Get-NetworkRange 192.168.1.5 255.255.255.248"
RunExample "Get-NetworkRange 172.18.0.23 30"
RunExample "Get-NetworkRange 172.18.0.23/29"