Implement IPConfig class to encapsulate network interface details and refactor Get-NetIPConfiguration to utilize it

Author: MariusStorhaug

src/classes/public/IPConfig.ps1

@@ -0,0 +1,69 @@
+class IPConfig {
+    # The interface name
+    [string] $InterfaceName
+
+    # The interface description
+    [string] $Description
+
+    # The interface status
+    [System.Net.NetworkInformation.OperationalStatus] $Status
+
+    # The address family
+    [string] $AddressFamily
+
+    # The IP address
+    [string] $IPAddress
+
+    # The prefix length
+    [int] $PrefixLength
+
+    # The subnet mask
+    [string] $SubnetMask
+
+    # The gateway
+    [string] $Gateway
+
+    # The DNS servers
+    [string] $DNSServers
+
+    IPConfig(
+        [System.Net.NetworkInformation.NetworkInterface] $Interface,
+        [System.Net.NetworkInformation.UnicastIPAddressInformation] $AddressInformation,
+        [System.Net.NetworkInformation.IPInterfaceProperties] $InterfaceProperties
+    ) {
+        $this.InterfaceName = $Interface.Name
+        $this.Description = $Interface.Description
+        $this.Status = $Interface.OperationalStatus
+        $this.AddressFamily = $AddressInformation.Address.AddressFamily.ToString()
+        $this.IPAddress = $AddressInformation.Address.IPAddressToString
+        $this.PrefixLength = $AddressInformation.PrefixLength
+
+        if ($AddressInformation.Address.AddressFamily -eq [System.Net.Sockets.AddressFamily]::InterNetwork) {
+            $this.SubnetMask = [IPConfig]::ConvertPrefixToMask($AddressInformation.PrefixLength)
+        } else {
+            # IPv6 masks are represented by prefix length
+            $this.SubnetMask = $null
+        }
+
+        $this.Gateway = ($InterfaceProperties.GatewayAddresses | ForEach-Object { $_.Address.IPAddressToString }) -join ', '
+        $this.DNSServers = ($InterfaceProperties.DnsAddresses | ForEach-Object { $_.IPAddressToString }) -join ', '
+    }
+
+    hidden static [string] ConvertPrefixToMask([int] $prefixLength) {
+        if ($prefixLength -le 0) { return '0.0.0.0' }
+        if ($prefixLength -ge 32) { return '255.255.255.255' }
+
+        [int[]] $octets = 0, 0, 0, 0
+        $bits = $prefixLength
+        for ($i = 0; $i -lt 4; $i++) {
+            $take = [Math]::Min(8, $bits)
+            if ($take -le 0) {
+                $octets[$i] = 0
+            } else {
+                $octets[$i] = 255 - ([math]::Pow(2, (8 - $take)) - 1)
+            }
+            $bits -= $take
+        }
+        return ($octets -join '.')
+    }
+}

src/functions/public/Get-NetIPConfiguration.ps1

@@ -79,27 +79,7 @@
         }
 
         foreach ($addr in $unicast) {
-            $prefixLength = $addr.PrefixLength
-            $mask = if ($addr.Address.AddressFamily -eq [System.Net.Sockets.AddressFamily]::InterNetwork) {
-                Get-SubnetMaskFromPrefix $prefixLength
-            } else {
-                # IPv6 masks are represented by prefix length
-                $null
-            }
-
-            [PSCustomObject]@{
-                InterfaceName = $adapter.Name
-                Description   = $adapter.Description
-                Status        = $adapter.OperationalStatus
-                AddressFamily = $addr.Address.AddressFamily.ToString()
-                IPAddress     = $addr.Address.IPAddressToString
-                PrefixLength  = $prefixLength
-                SubnetMask    = $mask
-                Gateway       = ($ipProps.GatewayAddresses |
-                        ForEach-Object { $_.Address.IPAddressToString }) -join ', '
-                DNSServers    = ($ipProps.DnsAddresses |
-                        ForEach-Object { $_.IPAddressToString }) -join ', '
-            }
+            [IPConfig]::new($adapter, $addr, $ipProps)
         }
     }
 }