WOL .net :: Snippet :: lucamauri.com

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WOL .net
Codename: wol

Wake-On-LAN (WOL) is a feature of the network interface cards since the late '90s
This functionality was initially conceived by IBM and the widely supported by Intel with NIC's and motherboard's chipset

WOL simply works by broadcasting a so called Magic Packet on the LAN where the device you want to wake-up is on. The Magic Packet is made by a leading HEX string followed by 16 repetition of the target MAC Address.
For the following class to works you must simply create an instance, provide the MAC Address and call the method WakeIt.
The class also includes Intellisense description.

Following the full code of the snippet
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                Imports System.Net
Imports System.Net.Sockets
Imports System.Text

Public Class clsWOL
    Const lenHeader As Integer = 6
    Const lenMAC As Integer = 6
    Const repMAC As Integer = 16

    Dim mEndPoint As IPEndPoint
    Dim mMACAddress As Byte()
    Dim mBytesSent As Integer = 0
    Dim mPacketSent As String

    ''' <summary>
    ''' The IPEndPoint object that will act as a trasport for the packet.
    ''' It is automatically created by New statement, but you can modify it or read it.
    ''' </summary>
    ''' <value>An IPEndPoint object</value>
    ''' <returns>An IPEndPoint object</returns>
    ''' <remarks>Normally there is no need to change this manually.</remarks>
    Public Property endPoint() As IPEndPoint
        Get
            Return mEndPoint
        End Get
        Set(ByVal value As IPEndPoint)
            mEndPoint = value
        End Set
    End Property
    ''' <summary>
    ''' The target machine Network Interface Card MAC address.
    ''' It must be dash-separated, i.e. in the 11-22-33-44-55-66 form
    ''' </summary>
    ''' <value>A string with dash-separated values</value>
    ''' <returns>A string with dash-separated values</returns>
    ''' <remarks>The standard (IEEE 802) separator for cotet are dash (-) and semicolon (:). I resolved to use dashes only in order to avoid any possible confusion and misunderstanding with upcoming IPv6 addressing space.</remarks>
    Public Property macAddress() As String
        Get
            Dim textMAC As New StringBuilder

            For Each currByte As Byte In mMACAddress
                textMAC.Append("-")
                textMAC.Append(currByte.ToString("X2"))
            Next

            Return textMAC.ToString.Substring(1)
        End Get
        Set(ByVal value As String)
            Dim values As Byte()

            For Each currByte As String In value.Split("-")
                If values Is Nothing Then
                    ReDim values(0)
                Else
                    ReDim Preserve values(values.GetUpperBound(0) + 1)
                End If
                values(values.GetUpperBound(0)) = Byte.Parse(currByte, Globalization.NumberStyles.HexNumber)
            Next

            mMACAddress = values
        End Set
    End Property
    ''' <summary>
    ''' Total bytes sent by WakeIt method. It is 0 until the method is called at least once for this class instance.
    ''' </summary>
    ''' <returns>Integer value, total bytes trasmitted</returns>
    ''' <remarks></remarks>
    Public ReadOnly Property bytesSent() As Integer
        Get
            Return mBytesSent
        End Get
    End Property
    ''' <summary>
    ''' It represent the Magic Packet broadcasted.
    ''' </summary>
    ''' <returns>String containing the text parsing of the Magic Packet</returns>
    ''' <remarks></remarks>
    Public ReadOnly Property packetSent() As String
        Get
            Return mPacketSent
        End Get
    End Property
    ''' <summary>
    ''' Creates a WOL Magic Packet, the datagram that will awake the target PC updon broadcast on the network.
    ''' </summary>
    ''' <param name="macAddress">An array of byte representing the target machine Network Interface Card MAC address</param>
    ''' <returns>An array of byte representing the Magic Packet</returns>
    ''' <remarks>This method can be used indipendently from the rest of the class. If necessary it can create a Magic Packet just providing the MAC address.</remarks>
    Public Function magicPacket(ByVal macAddress As Byte()) As Byte()
        Dim payloadData As Byte()
        Dim packet As New StringBuilder

        Try
            ReDim payloadData(lenHeader + lenMAC * repMAC)

            For i As Integer = 0 To lenHeader - 1
                payloadData(i) = Byte.Parse("FF", Globalization.NumberStyles.HexNumber)
            Next
            For i As Integer = 0 To repMAC - 1
                For j As Integer = 0 To lenMAC - 1
                    payloadData(lenHeader + i * lenMAC + j) = macAddress(j)
                Next
            Next

            For Each currLoad As Byte In payloadData
                packet.Append("-")
                packet.Append(currLoad.ToString("X2"))
            Next

            mPacketSent = packet.ToString.Substring(1)
        Catch ex As Exception
            mPacketSent = "EXCEPTION: " & ex.ToString
        End Try

        Return payloadData
    End Function

    Function sendUDP(ByVal payload As Byte(), ByVal endPoint As IPEndPoint) As Integer
        Dim byteSend As Integer
        Dim socketClient As Socket

        If (payload IsNot Nothing) AndAlso (endPoint IsNot Nothing) Then
            socketClient = New Socket(endPoint.AddressFamily, SocketType.Dgram, ProtocolType.Udp)
            socketClient.Connect(endPoint)
            byteSend = socketClient.Send(payload, 0, payload.Length, SocketFlags.None)

            socketClient.Close()
        Else
            byteSend = 0
        End If

        Return byteSend
    End Function
    ''' <summary>
    ''' It is the main method of the class. It must be called after the MAC address has been set. It does not return any code, you can see the result of the operation with the bytesSent and packetSent properties of this class.
    ''' </summary>
    ''' <remarks></remarks>
    Public Sub wakeIt()
        mBytesSent = sendUDP(magicPacket(mMACAddress), mEndPoint)
    End Sub
    ''' <summary>
    ''' No parameter is required. The new statement just created the IPEndPoint object.
    ''' </summary>
    ''' <remarks>The default IPEndPoint transmit on port 7. Other choices for WOL are port 0 or 9</remarks>
    Sub New()
        mEndPoint = New IPEndPoint(IPAddress.Broadcast, 7)
    End Sub
    ''' <summary>
    ''' The IPEndPoint object is created to the specified port
    ''' </summary>
    ''' <param name="epPort">A valid port number</param>
    ''' <remarks>If the port number is invalid, the IPEndPoint is created to port 7. Ports normally used for WOL are 0, 7 or 9.</remarks>
    Sub New(ByVal epPort As Integer)
        If epPort >= 0 AndAlso epPort < 65535 Then
            mEndPoint = New IPEndPoint(IPAddress.Broadcast, epPort)
        Else
            mEndPoint = New IPEndPoint(IPAddress.Broadcast, 7)
        End If
    End Sub
End Class

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