From 7faa4d84c4adfb88b9bcd4764285e3844fcd4b18 Mon Sep 17 00:00:00 2001
From: Asif Bacchus <asif@asifbacchus.dev>
Date: Sat, 4 Sep 2021 00:58:30 -0600
Subject: [PATCH] struct(modules): working skeleton magic-packet function

- function to send magic packet
- basic validation and error trapping
- need to use cleaner error trapping
- need to add inline help
---
 wol-magicPacket.psm1 | 79 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 wol-magicPacket.psm1

diff --git a/wol-magicPacket.psm1 b/wol-magicPacket.psm1
new file mode 100644
index 0000000..6d50a33
--- /dev/null
+++ b/wol-magicPacket.psm1
@@ -0,0 +1,79 @@
+function Send-MagicPacket
+{
+    [CmdletBinding()]
+    param
+    (
+    # Array of MAC addresses for which to construct magic packets
+        [Parameter(Mandatory, ValueFromPipeline, ValueFromPipelineByPropertyName)]
+        [ValidatePattern('^([0-9A-F]{2}[:-]){5}([0-9A-F]{2})$')]
+        [String[]]
+        $MacAddress,
+
+    # Broadcast IP address (default: all subnets --> 255.255.255.255)
+        [Parameter()]
+        [IPAddress]
+        $BroadcastIP = [System.Net.IPAddress]::Broadcast,
+
+    # UDP port over which to broadcast magic packet (default: 7)
+        [Parameter()]
+        [Int16]
+        $Port = 7
+    )
+
+    begin
+    {
+        # instantiate UDP client
+        try
+        {
+            $UdpClient = [System.Net.Sockets.UdpClient]::new()
+        }
+        catch
+        {
+            Write-Error "Unable to instantiate UDP Client to send magic packets"
+        }
+    }
+
+    process
+    {
+        foreach ($addr in $MacAddress)
+        {
+            # convert MAC address to magic packet
+            try
+            {
+                # construct byte-array from MAC address
+                $MAC = $addr -split '[:-]' | ForEach-Object {
+                    [Byte]"0x$_"
+                }
+
+                # construct magic packet
+                # first 6 bytes = FF (255) then repeat MAC address 16 times
+                [Byte[]]$magicPacket = (,0xFF * 6) + ($MAC * 16)
+            }
+            catch
+            {
+                Write-Warning "Unable to process MAC address: $thisMacAddress"
+                continue
+            }
+
+            # broadcast magic packet
+            try
+            {
+                $UdpClient.Connect($BroadcastIP, $Port)
+                $UdpClient.Send($magicPacket, $magicPacket.Length) | Out-Null
+                Write-Verbose "Sent magic packet: Broadcast $addr over $BroadcastIP on port $Port (UDP)"
+            }
+            catch
+            {
+                Write-Warning "Unable to send magic packet for '$addr'"
+                continue
+            }
+        }
+    }
+
+    end
+    {
+        # dispose of UDP client
+        $UdpClient.Close()
+        $UdpClient.Dispose()
+    }
+}
\ No newline at end of file