Fixes multi interface support on interface discover

* Fixes issue on hosts with mulitple interfaces that provide virtual
interfaces, causing problems on Director Self-Service creation
* Adds support for Windows 2008 R2

doc/31-Changelog.md

@@ -13,6 +13,7 @@ Released closed milestones can be found on [GitHub](https://github.com/Icinga/ic
 
 ### Bugfixes
 
+* [#059](https://github.com/Icinga/icinga-powershell-framework/issues/059), [#060](https://github.com/Icinga/icinga-powershell-framework/pull/060) Fixes interface handling for multiple interfaces and returns only the main interface by fallback to routing table and adds support for Windows 2008 R2
 * [#127](https://github.com/Icinga/icinga-powershell-framework/issues/127) Fixes wrong error message on failed MSSQL connection due to database not reachable by using `-IntegratedSecurity`
 * [#128](https://github.com/Icinga/icinga-powershell-framework/issues/128) Fixes unhandled output from loading `System.Reflection.Assembly` which can cause weird side effects for plugin outputs
 * [#130](https://github.com/Icinga/icinga-powershell-framework/issues/130) Fix crash while running services as background task to collect metrics over time by missing Performance Counter cache initialisation

lib/core/tools/Get-IcingaNetworkInterface.psm1

@@ -36,6 +36,13 @@ function Get-IcingaNetworkInterface()
         return $null;
     }
 
+    # Ensure that we can still process on older Windows system where
+    # Get-NetRoute ist not available
+    if ((Test-IcingaFunction 'Get-NetRoute') -eq $FALSE) {
+        Write-IcingaConsoleWarning 'Your Windows system does not support "Get-NetRoute". A fallback solution is used to fetch the IP of the first Network Interface routing through 0.0.0.0'
+        return (Get-IcingaNetworkRoute).Interface;
+    }
+
     try {
         [array]$IP = ([System.Net.Dns]::GetHostAddresses($IP)).IPAddressToString;
     } catch {
@@ -151,13 +158,20 @@ function Get-IcingaNetworkInterface()
     }
 
     $InternalCount        = 0;
-    $UseInterface  = '';
+    [array]$UseInterface  = @();
     foreach ($interface in $ExternalInterfaces.Keys) {
         $currentCount = $ExternalInterfaces[$interface].count;
         if ($currentCount -gt $InternalCount) {
             $InternalCount = $currentCount;
-            $UseInterface = $interface;
+            $UseInterface += $interface;
         }
     }
-    return $UseInterface;
+
+    # In case we found multiple interfaces, fallback to our
+    # 'route print' function and return this interface instead
+    if ($UseInterface.Count -ne 1) {
+        return (Get-IcingaNetworkRoute).Interface;
+    }
+
+    return $UseInterface[0];
 }

lib/core/tools/Get-IcingaNetworkRoute.psm1

@@ -0,0 +1,37 @@
+<#
+.SYNOPSIS
+   Fetch the used interface for our Windows System
+.DESCRIPTION
+   Newer Windows systems provide a Cmdlet 'Get-NetRoute' for fetching the
+   network route configurations. Older systems however do not provide this
+   and to ensure some sort of backwards compatibility, we will have a look
+   on our route configuration and return the first valid interface found
+.FUNCTIONALITY
+   This Cmdlet will return first valid IP for our interface
+.EXAMPLE
+   PS>Get-IcingaNetworkRoute
+.OUTPUTS
+   System.Array
+.LINK
+   https://github.com/Icinga/icinga-powershell-framework
+.NOTES
+#>
+
+function Get-IcingaNetworkRoute()
+{
+    $RouteConfig = (&route print | Where-Object {
+        $_.TrimStart() -Like "0.0.0.0*";
+    }).Split() | Where-Object {
+        return $_;
+    };
+
+    $Interface   = @{
+        'Destination' = $RouteConfig[0];
+        'Netmask'     = $RouteConfig[1];
+        'Gateway'     = $RouteConfig[2];
+        'Interface'   = $RouteConfig[3];
+        'Metric'      = $RouteConfig[4];
+    }
+
+    return $Interface;
+}