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CIDR to IP range conversion using PowerShell
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| # calculate IP address range from CIDR notation | |
| # https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing | |
| function cidrToIpRange { | |
| param ( | |
| [string] $cidrNotation | |
| ) | |
| $addr, $maskLength = $cidrNotation -split '/' | |
| [int]$maskLen = 0 | |
| if (-not [int32]::TryParse($maskLength, [ref] $maskLen)) { | |
| write-warning "No mask, setting to /32" | |
| $masklen = 32 | |
| } | |
| if (0 -gt $maskLen -or $maskLen -gt 32) { | |
| throw "CIDR mask length must be between 0 and 32" | |
| } | |
| $ipAddr = [Net.IPAddress]::Parse($addr) | |
| if ($ipAddr -eq $null) { | |
| throw "Cannot parse IP address: $addr" | |
| } | |
| if ($ipAddr.AddressFamily -ne [Net.Sockets.AddressFamily]::InterNetwork) { | |
| throw "Can only process CIDR for IPv4" | |
| } | |
| $shiftCnt = 32 - $maskLen | |
| $mask = -bnot ((1 -shl $shiftCnt) - 1) | |
| $ipNum = [Net.IPAddress]::NetworkToHostOrder([BitConverter]::ToInt32($ipAddr.GetAddressBytes(), 0)) | |
| $ipStart = ($ipNum -band $mask) | |
| $ipEnd = ($ipNum -bor (-bnot $mask)) | |
| # return | |
| return [PSCustomObject]@{ | |
| Start = ([BitConverter]::GetBytes([Net.IPAddress]::HostToNetworkOrder($ipStart)) | ForEach-Object { $_ } ) -join '.' | |
| End = ([BitConverter]::GetBytes([Net.IPAddress]::HostToNetworkOrder($ipEnd)) | ForEach-Object { $_ } ) -join '.' | |
| } | |
| } | |
| # Test | |
| $ips = @('1.2.3.4/24', '9.8.7.6') | |
| $ips | % { cidrToIpRange $_ } | sort-object start |
Yup, you're right. Updated.
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Looks good (Did a few tests).
Missing a } on row 37