002.DnsRecordPtr.ps1 - expandIPv6String only working in edge cases

Nabsku commented 3 years ago

Hi,

started using your Dsc module to automate our Ptr deployment via ansible and I found a pretty severe bug/issue that I'd like to point out.

https://github.com/dsccommunity/DnsServerDsc/blob/b17d68fa8188b6bd4c24ae875f510aa3529b1e54/source/Classes/002.DnsRecordPtr.ps1#L142-L146

This logic does not work when you're using an IPv6 like 2a1f:2786:9:1::11. All it does is add zeroes between segments 2a1f and 2787.

I've hotfixed the issue in our own infrastructure and I'd like to share it with you guys so you can include a similar fix in your own code.

    $segments = [System.Collections.ArrayList]::new($string -split ':')

    $newSegments  = [System.Collections.ArrayList]::new()

    $blankSegmentCount = 8 - $segments.count

    foreach($segment in $segments){
        if([string]::IsNullOrEmpty($segment)){
            for ($i = 0; $i -le $blankSegmentCount; $i++)
            {
                $newSegments.Add('0000')
            }
        } else {
            $newSegments.Add($segment)
        }
    }

    # Insert missing segments
    #for ($i = 0; $i -lt $blankSegmentCount; $i++)
    #{
    #    $segments.Insert(1, '0000')
    #}

    # Pad out all segments with leading zeros
    $paddedSegments = $newSegments | ForEach-Object {
        $_.PadLeft(4, '0')
    }

    return ($paddedSegments -join ':')