Imports System.Net
Module Module1
    Dim HostName As New ArrayList
    Dim IPv4 As New ArrayList
    Dim SubnetMask As New ArrayList
    Dim SystemGateWay As New ArrayList
    Dim DNS1 As New ArrayList
    Dim DNS2 As New ArrayList
    Dim NetworkCount As Integer = 0 'Count the number of network this PC is connected to. If more than two, require for selection
    Dim highPossibility As Integer = 0
    Dim results As New ArrayList
    Dim AOBFound As New ArrayList
    Dim threads As New ArrayList
    Sub Main()
        Console.WriteLine("Home Dynamic Local Area Network Scanning Utlities")
        GetAllIP()
        If NetworkCount > 1 Then
            'Ask for which network to scan.
            Console.WriteLine("Multiple Network Found. Auto-selecting network " & highPossibility & "." & vbNewLine & "Selected gateway: " & SystemGateWay(highPossibility) & ".")
        End If
        pingAllIPsInSubnet(highPossibility)
        Console.WriteLine("IP Scanning Done.")
        results.Sort()
        Console.WriteLine("The following IPs respond to ping")
        FindAllAOB()
        Console.WriteLine("AOB System are located on these hosts: ")
        For k As Integer = 0 To AOBFound.Count - 1
            Console.WriteLine(AOBFound.Item(k))
        Next
        If AOBFound.Count = 1 Then
            Process.Start("http://" & AOBFound.Item(0))
        End If
        Console.WriteLine("DONE")
        Console.Read()
    End Sub
    Public Sub FindAllAOB()
        threads.Clear()
        For k As Integer = 0 To results.Count - 1
            Dim thisIP As String = results.Item(k)
            Dim newThread As New System.Threading.Thread(Sub() SendWebRequest(thisIP))
            threads.Add(newThread)
            newThread.Start()
            Console.WriteLine("Starting AOB connection on : " & thisIP)
        Next

        Dim running As Integer = results.Count - 1
        Dim lastvalue As Integer = 0
        While running > 0
            running = 0
            For i As Integer = 0 To threads.Count - 1
                If (threads.Item(i).IsAlive) Then
                    running += 1
                End If
            Next
            If running <> lastvalue Then
                Console.WriteLine("Still waiting " & running & " threads to end.")
            End If
            lastvalue = running
            Threading.Thread.Sleep(200)
        End While
    End Sub

    Public Sub SendWebRequest(ip)
        Dim req As System.Net.WebRequest
        Dim res As System.Net.WebResponse

        req = System.Net.WebRequest.Create("http://" & ip & "/AOB")
        Try
            res = req.GetResponse()
            Console.WriteLine("AOB System Found on " & ip)
            AOBFound.Add(ip)
        Catch e As WebException
            Console.WriteLine("AOB not found on ip: " & ip)
        End Try

    End Sub


    Public Function getMaskValue(mask)
        If mask = "255.255.255.0" Then
            Return 1
        ElseIf mask = "255.255.0.0" Then
            Return 2
        Else
            Return -1 'Not supported for such a large network
        End If
    End Function

    Public Sub pingAllIPsInSubnet(networkid As Integer)
        Dim ip As String = IPv4.Item(networkid)
        Dim mk As String = SubnetMask.Item(networkid)
        Dim mkv As Integer = getMaskValue(mk)
        If (mkv <> -1) Then
            If mkv = 1 Then
                For d As Integer = 1 To 254
                    Dim thisIP = ip.Substring(0, ip.LastIndexOf(".")) & "." & d.ToString
                    Dim newThread As New System.Threading.Thread(Sub() CheckIfIpAlive(thisIP))
                    threads.Add(newThread)
                    newThread.Start()
                    Console.WriteLine("Starting thread to connect : " & thisIP)
                    'Threading.Thread.Sleep(200)
                Next

                Dim running As Integer = 254
                Dim lastvalue As Integer = 0
                While running > 0
                    running = 0
                    For i As Integer = 0 To threads.Count - 1
                        If (threads.Item(i).IsAlive) Then
                            running += 1
                        End If
                    Next
                    If running <> lastvalue Then
                        Console.WriteLine("Still waiting " & running & " threads to end.")
                    End If
                    lastvalue = running
                    Threading.Thread.Sleep(200)
                End While
            ElseIf mkv = 2 Then
                Console.Write("Currently not supported")
            End If

        Else
            Console.Write("Network too big. Please set up manually.")
            Return
        End If
    End Sub

    Public Sub CheckIfIpAlive(thisip)
        If tryPing(thisip) = True Then
            results.Add(thisip)
        End If

    End Sub



    Private Function FillZeros(val)
        If val < 10 Then
            Return "00" & val.ToString
        ElseIf val < 100 Then
            Return "0" & val.ToString
        Else
            Return val.ToString
        End If
    End Function


    Public Sub GetAllIP()
        'On Error Resume Next
        HostName.Add(System.Net.Dns.GetHostName())
        For Each ip In System.Net.Dns.GetHostEntry(HostName.Item(NetworkCount)).AddressList
            If ip.AddressFamily = Net.Sockets.AddressFamily.InterNetwork Then
                'IPv4 Adress
                IPv4.Add(ip.ToString())
                For Each adapter As Net.NetworkInformation.NetworkInterface In Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces()
                    For Each unicastIPAddressInformation As Net.NetworkInformation.UnicastIPAddressInformation In adapter.GetIPProperties().UnicastAddresses
                        If unicastIPAddressInformation.Address.AddressFamily = Net.Sockets.AddressFamily.InterNetwork Then
                            If ip.Equals(unicastIPAddressInformation.Address) Then
                                'Subnet Mask
                                SubnetMask.Add(unicastIPAddressInformation.IPv4Mask.ToString())

                                Dim adapterProperties As Net.NetworkInformation.IPInterfaceProperties = adapter.GetIPProperties()
                                For Each gateway As Net.NetworkInformation.GatewayIPAddressInformation In adapterProperties.GatewayAddresses
                                    'Default Gateway
                                    SystemGateWay.Add(gateway.Address.ToString())
                                Next

                                'DNS1
                                If adapterProperties.DnsAddresses.Count > 0 Then
                                    DNS1.Add(adapterProperties.DnsAddresses(0).ToString())
                                End If

                                'DNS2
                                If adapterProperties.DnsAddresses.Count > 1 Then
                                    DNS2.Add(adapterProperties.DnsAddresses(1).ToString())
                                End If
                            End If
                            End If
                    Next
                Next


                Console.WriteLine("IPv4: " & IPv4.Item(NetworkCount))
                Console.WriteLine("Subnet Mask: " & SubnetMask.Item(NetworkCount))
                If (SystemGateWay.Count <= NetworkCount) Then
                    SystemGateWay.Add("N/A")
                Else
                    highPossibility = NetworkCount
                End If
                Console.WriteLine("Gateway: " & SystemGateWay.Item(NetworkCount))
                Console.WriteLine("")
                NetworkCount += 1

                End If
        Next
    End Sub

    Public Function tryPing(ip As String)
        On Error GoTo errorPoint
        If My.Computer.Network.Ping(ip) Then
            Return True
        Else
errorPoint:
            Return False
        End If
    End Function
End Module