Ping in .NET

[Addict]

We all know that it was cake with VB6. And I'm just now getting the jist of sockets with .NET. What a trip.... Anyhow.

I have the basic code for a ping. I got a nice jump start from http://www.fawcette.com/vsm/2002_03/...qa/default.asp .

My problem is that the .ReceiveFrom seems to take 100+ milliseconds to complete. While that may not seem like much, it is when you're trying to time the ping. Also, it tends to hang if I try to repeat the ping. I get "Non-blocking socket operation could not be completed immediately".

Any thoughts? The code is below.

 Public Sub Echo(ByVal RemoteName As String, ByVal DataSize As Byte, ByVal pStatus As Label)
        'for timing
        Dim intStart As Integer
        'for timing
        Dim intEnd As Integer
        'address/port of remote host
        Dim RemoteHost As IPEndPoint
        Dim rhEP As EndPoint
        'id of this packet
        Dim Identifier As Short = 0
        'sequence number of this packet
        Dim Sequence As Short = 0
        'the socket we use to connect and
        'send data through
        Dim ICMPSocket As Socket
        'the request buffer
        Dim RequestBuffer() As Byte
        'the reply buffer
        Dim ReplyBuffer(255) As Byte
        'the number of bytes received
        Dim RecvSize As Integer = 0

        RemoteHost = GetRemoteEndpoint(RemoteName)
        rhEP = CType(RemoteHost, System.Net.EndPoint)

        DataSize = Convert.ToByte(DataSize + bufferHeaderSize)
        ' If odd data size, we need to add
        ' one empty byte
        If (DataSize Mod 2 = 1) Then
            DataSize += Convert.ToByte(1)
        End If
        ReDim RequestBuffer(DataSize - 1)

        ' Set Type Field
        RequestBuffer(0) = Convert.ToByte(ICMPType.Echo)
        ' Set ID Field
        BitConverter.GetBytes(Identifier).CopyTo(RequestBuffer, 4)
        ' Set Sequence Field
        BitConverter.GetBytes(Sequence).CopyTo(RequestBuffer, 6)

        ' load some data into buffer
        Dim i As Integer
        For i = 8 To DataSize - 1
            RequestBuffer(i) = Convert.ToByte(i Mod 8)
        Next i

        ' Set Checksum
        Call CreateChecksum(RequestBuffer, DataSize, RequestBuffer(2), RequestBuffer(3))

        Try
            ICMPSocket = New Socket(AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp)
            ICMPSocket.Blocking = False

            'Start Count
            intStart = System.Environment.TickCount
            'Send Data
            ICMPSocket.SendTo(RequestBuffer, 0, DataSize, SocketFlags.None, RemoteHost)
            'Receive Data
            RecvSize = ICMPSocket.ReceiveFrom(ReplyBuffer, SocketFlags.None, rhEP)
            'End Count
            intEnd = System.Environment.TickCount

            If RecvSize > 0 Then
                Dim ReS As String
                Select Case ReplyBuffer(20)
                    Case Convert.ToByte(ICMPType.EchoReply)
                        ReS = (intEnd - intStart).ToString
                        pStatus.Text = "Host: " + RemoteHost.Address.ToString + " - RTT: " + ReS
                    Case Convert.ToByte(ICMPType.Unreachable)
                        ReS = "Unreachable"
                        pStatus.Text = ReS
                    Case Else
                        ReS = "Something Happened"
                        pStatus.Text = ReS
                End Select
            End If

        Catch e As Exception
            MessageBox.Show(e.Message + vbNewLine + e.TargetSite.Name)
        Finally
            If Not ICMPSocket Is Nothing Then
                ICMPSocket.Close()
            End If
        End Try
    End Sub

    Public Function GetRemoteEndpoint(ByVal RemoteAddress As String) As IPEndPoint
        Return New IPEndPoint(Dns.Resolve(RemoteAddress).AddressList(0), portICMP)
    End Function