' This is the listener example that shows how to use the MulticastOption class. 
' In particular, it shows how to use the MulticastOption(IPAddress, IPAddress) 
' constructor, which you need to use if you have a host with more than one 
' network card.
' The first parameter specifies the multicast group address, and the second 
' specifies the local address of the network card you want to use for the data
' exchange.
' You must run this program in conjunction with the sender program as 
' follows:
' Open a console window and run the listener from the command line. 
' In another console window run the sender. In both cases you must specify 
' the local IPAddress to use. To obtain this address run the ipconfig command 
' from the command line. 


Imports System.Net
Imports System.Net.Sockets
Imports System.Text

Namespace Mssc.TransportProtocols.Utilities

  Module M_TestMulticastOption

    Public Class TestMulticastOption

      Private Shared mcastAddress As IPAddress
      Private Shared mcastPort As Integer
      Private Shared mcastSocket As Socket
      Private Shared mcastOption As MulticastOption


      Private Shared Sub MulticastOptionProperties()
        Console.WriteLine(("Current multicast group is: " + mcastOption.Group.ToString()))
        Console.WriteLine(("Current multicast local address is: " + mcastOption.LocalAddress.ToString()))
      End Sub


      Private Shared Sub StartMulticast()

        Try
          mcastSocket = New Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp)

          Console.Write("Enter the local IP address: ")

          Dim localIPAddr As IPAddress = IPAddress.Parse(Console.ReadLine())

          'IPAddress localIP = IPAddress.Any;
          Dim localEP As EndPoint = CType(New IPEndPoint(localIPAddr, mcastPort), EndPoint)

          mcastSocket.Bind(localEP)

          ' Define a MulticastOption object specifying the multicast group 
          ' address and the local IPAddress.
          ' The multicast group address is the same as the address used by the server.
          mcastOption = New MulticastOption(mcastAddress, localIPAddr)

          mcastSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, mcastOption)

        Catch e As Exception
          Console.WriteLine(e.ToString())
        End Try
      End Sub


      Private Shared Sub ReceiveBroadcastMessages()
        Dim done As Boolean = False
        Dim bytes() As Byte = New [Byte](99) {}
        Dim groupEP As New IPEndPoint(mcastAddress, mcastPort)
        Dim remoteEP As EndPoint = CType(New IPEndPoint(IPAddress.Any, 0), EndPoint)


        Try
          While Not done
            Console.WriteLine("Waiting for multicast packets.......")
            Console.WriteLine("Enter ^C to terminate.")

            mcastSocket.ReceiveFrom(bytes, remoteEP)

            Console.WriteLine("Received broadcast from {0} :" + ControlChars.Lf + " {1}" + ControlChars.Lf, groupEP.ToString(), Encoding.ASCII.GetString(bytes, 0, bytes.Length))
          End While



          mcastSocket.Close()

        Catch e As Exception
          Console.WriteLine(e.ToString())
        End Try
      End Sub


      Public Shared Sub Main(ByVal args() As String)
        ' Initialize the multicast address group and multicast port.
        ' Both address and port are selected from the allowed sets as
        ' defined in the related RFC documents. These are the same
        ' as the values used by the sender.
        mcastAddress = IPAddress.Parse("224.168.100.2")
        mcastPort = 11000

        ' Start a multicast group.
        StartMulticast()

        ' Display MulticastOption properties.
        MulticastOptionProperties()

        ' Receive broadcast messages.
        ReceiveBroadcastMessages()
      End Sub
    End Class

  End Module

End Namespace

' This sender example must be used in conjunction with the listener program.
' You must run this program as follows:
' Open a console window and run the listener from the command line. 
' In another console window run the sender. In both cases you must specify 
' the local IPAddress to use. To obtain this address, run the ipconfig command
' from the command line. 
'  
Imports System.Net.Sockets
Imports System.Net
Imports System.Text

Namespace Mssc.TransportProtocols.Utilities

  Module M_TestMulticastOption

    Class TestMulticastOption

      Private Shared mcastAddress As IPAddress
      Private Shared mcastPort As Integer
      Private Shared mcastSocket As Socket


      Shared Sub JoinMulticastGroup()
        Try
          ' Create a multicast socket.
          mcastSocket = New Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp)

          ' Get the local IP address used by the listener and the sender to
          ' exchange multicast messages. 
          Console.Write(ControlChars.Lf + "Enter local IPAddress for sending multicast packets: ")
          Dim localIPAddr As IPAddress = IPAddress.Parse(Console.ReadLine())

          ' Create an IPEndPoint object. 
          Dim IPlocal As New IPEndPoint(localIPAddr, 0)

          ' Bind this endpoint to the multicast socket.
          mcastSocket.Bind(IPlocal)

          ' Define a MulticastOption object specifying the multicast group 
          ' address and the local IP address.
          ' The multicast group address is the same as the address used by the listener.
          Dim mcastOption As MulticastOption
          mcastOption = New MulticastOption(mcastAddress, localIPAddr)

          mcastSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, mcastOption)

        Catch e As Exception
          Console.WriteLine((ControlChars.Lf + e.ToString()))
        End Try
      End Sub


      Shared Sub BroadcastMessage(ByVal message As String)
        Dim endPoint As IPEndPoint

        Try
          'Send multicast packets to the listener.
          endPoint = New IPEndPoint(mcastAddress, mcastPort)
          mcastSocket.SendTo(ASCIIEncoding.ASCII.GetBytes(message), endPoint)
          Console.WriteLine("Multicast data sent.....")
        Catch e As Exception
          Console.WriteLine((ControlChars.Lf + e.ToString()))
        End Try

        mcastSocket.Close()
      End Sub


      Public Shared Sub Main(ByVal args() As String)
        ' Initialize the multicast address group and multicast port.
        ' Both address and port are selected from the allowed sets as
        ' defined in the related RFC documents. These are the same as the 
        ' values used by the sender.
        mcastAddress = IPAddress.Parse("224.168.100.2")
        mcastPort = 11000

        ' Join the listener multicast group.
        JoinMulticastGroup()

        ' Broadcast the message to the listener.
        BroadcastMessage("Hello multicast listener.")
      End Sub
    End Class

  End Module

End Namespace