DnsRecordPtr: IPv6 hot fix (#256)

- Logic bug in DnsRecordPtr.expandIPv6String($string) (#255) - Supporting tests added
dsccommunity · May 15, 2021 · 66fb5b0 · 66fb5b0
1 parent b17d68f
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -94,6 +94,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - DnsServerScavenging
   - Moved to the same coding pattern as _DnsServerRecursion_.
 
+### Fixed
+
+- Logic bug in DnsRecordPtr.expandIPv6String($string) (#255)
+  - Supporting tests added
+
 ## [2.0.0] - 2021-03-26
 
 ### Deprecated

diff --git a/source/Classes/002.DnsRecordPtr.ps1 b/source/Classes/002.DnsRecordPtr.ps1
@@ -6,13 +6,13 @@
         The DnsRecordPtr DSC resource manages PTR DNS records against a specific zone on a Domain Name System (DNS) server.
 
     .PARAMETER IpAddress
-       Specifies the IP address to which the record is associated (Can be either IPv4 or IPv6. (Key Parameter)
+        Specifies the IP address to which the record is associated (Can be either IPv4 or IPv6. (Key Parameter)
 
     .PARAMETER Name
-       Specifies the FQDN of the host when you add a PTR resource record. (Key Parameter)
+        Specifies the FQDN of the host when you add a PTR resource record. (Key Parameter)
 
     .NOTES
-       Reverse lookup zones do not support scopes, so there should be no DnsRecordPtrScoped subclass created.
+        Reverse lookup zones do not support scopes, so there should be no DnsRecordPtrScoped subclass created.
 #>
 
 [DscResource()]
@@ -139,14 +139,26 @@ class DnsRecordPtr : DnsRecordBase
         # Determine how many segments need to be added to reach the 8 required
         $blankSegmentCount = 8 - $segments.count
 
+        # Hold the expanded segments
+        $newSegments  = [System.Collections.ArrayList]::new()
+
         # Insert missing segments
-        for ($i = 0; $i -lt $blankSegmentCount; $i++)
+        foreach ($segment in $segments)
         {
-            $segments.Insert(1, '0000')
+            if ([System.String]::IsNullOrEmpty($segment))
+            {
+                for ($i = 0; $i -le $blankSegmentCount; $i++)
+                {
+                    $newSegments.Add('0000')
+                }
+            } else
+            {
+                $newSegments.Add($segment)
+            }
         }
 
         # Pad out all segments with leading zeros
-        $paddedSegments = $segments | ForEach-Object {
+        $paddedSegments = $newSegments | ForEach-Object {
             $_.PadLeft(4, '0')
         }
         return ($paddedSegments -join ':')

diff --git a/tests/Unit/Classes/DnsRecordPtr.v6.tests.ps1 b/tests/Unit/Classes/DnsRecordPtr.v6.tests.ps1
@@ -23,6 +23,61 @@ Get-Module -Name 'DnsServer' -All | Remove-Module -Force
 Import-Module -Name "$($PSScriptRoot)\..\Stubs\DnsServer.psm1"
 
 InModuleScope $ProjectName {
+
+    Describe "Testing the expandIPv6String method for completeness (See Issue #255)" -Tag 'expandIPv6String', 'DnsRecord', 'DnsRecordPtr' {
+        $testObj = [DnsRecordPtr]::new()
+
+        Context "Expands the following addresses correctly" {
+            $testCases = @"
+3ea8:1140:571c:e8d8:2e83:cb3a:0000:9431
+c69e:276d:0e86:c274:c7f0:0000:8dc3:e662
+db8c:e4ec:32f7:41a2:0000:842e:d212:b4c2
+0a98:d329:7ed1:0000:a09e:8b35:19ea:5bd9
+53ed:054f:0000:8a4c:ed3b:218b:f2f2:a685
+e7b3:0000:4acf:f23c:d427:780a:f34c:833b
+164a:8626:55f8:c422:dd25:0000:0000:0a5b
+f0a0:fa5c:a0bf:5732:0000:0000:9b2e:2307
+afd4:640b:c7c3:0000:0000:c8b3:ae79:b2c4
+9b2e:7ede:0000:0000:6c70:0c44:26ff:39aa
+a5f2:0000:0000:ce7f:f152:e5bb:99de:7f7e
+5511:56ea:0b7c:fc9c:0000:0000:0000:664f
+6dc2:919a:ab83:0000:0000:0000:57e2:36c7
+13fa:2084:0000:0000:0000:8a14:bda1:377d
+122f:0000:0000:0000:f3e8:9a84:f1c5:674a
+ff02:6db3:354d:0000:0000:0000:0000:bc0c
+0018:0832:0000:0000:0000:0000:d4e7:71f4
+706e:0000:0000:0000:0000:98b5:ffe5:a652
+2950:e8ba:0000:0000:0000:0000:0000:f9ec
+e549:0000:0000:0000:0000:0000:9cca:40ad
+a788:0000:0000:0000:0000:0000:0000:c8db
+d730:a994:ff75:da7f:0000:8027:0000:0020
+2bb1:d12d:7fa2:5601:e9fa:22db:7412:51bd
+234d:0254:ac61:26df:56c5:25a1:eaf8:87cb
+0168:3293:f754:0000:bd31:f91a:0000:000e
+2b5b:b929:0243:529d:671b:597d:88be:28e9
+c74c:ca12:da15:bd3e:4037:ead2:6059:f14f
+4f85:bc16:e333:06b7:d948:60c1:5f61:66e3
+d861:9c60:c280:9f4e:705d:0b71:574d:7bdb
+493e:81ac:19f3:0dc5:042b:0c86:0a5b:b1cc
+7782:d54f:fc68:ceca:9d89:3879:a603:0e43
+7358:25cb:9973:d542:6658:9a9e:84d0:6b41
+"@ -split "`r*`n" | ForEach-Object {
+                @{
+                    FullAddress = $_
+                    CompactAddress = [System.Net.IpAddress]::Parse($_).IPAddressToString
+                }
+            }
+
+            It 'Expands <CompactAddress> -> <FullAddress>' -TestCases $testCases {
+                param (
+                    [System.String] $CompactAddress,
+                    [System.String] $FullAddress
+                )
+                $testObj.expandIPv6String($CompactAddress) | Should -Be $FullAddress
+            }
+        }
+    }
+
     Describe "Testing DnsRecordPtr Get Method (IPv6 inputs)" -Tag 'Get', 'DnsRecord', 'DnsRecordPtr' {
         BeforeEach {
             $script:instanceDesiredState = [DnsRecordPtr] @{