CIDR to Subnet in VB.NET2010

How can I replicate this in VB.NET 2010 in Framework 4?

Have searched for this code for over 5 hours and not one site has this code. There are a few that do subnet to cidr but that isn't the way I wish it to go. There is also on the net a VB6 project converted to vb.net but again it doesn't do what I want so pointless linking me to try

No Google links please as they will be ignored. If all you do is post links them please ruin another thread

Thanks in advance

Re: CIDR to Subnet in VB.NET2010

Try this :

Private Shared Sub Network2IpRange(sNetwork As String, ByRef startIP As UInteger, ByRef endIP As UInteger)
	' ip address 
	' subnet mask 
	' Broadcast address 
	Dim ip As UInteger, mask As UInteger, broadcast As UInteger, network As UInteger
	' Network address 

	Dim bits As Integer

	Dim elements As String() = sNetwork.Split(New [Char]() {"/"C})

	ip = IP2Int(elements(0))
	bits = Convert.ToInt32(elements(1))

	mask = Not (&HffffffffUI >> bits)

	network = ip And mask
	broadcast = network + Not mask

	usableIps = If((bits > 30), 0, (broadcast - network - 1))

	If usableIps <= 0 Then
		startIP = InlineAssignHelper(endIP, 0)
	Else
		startIP = network + 1
		endIP = broadcast - 1
	End If
End Sub

Public Shared Function IP2Int(IPNumber As String) As UInteger
	Dim ip As UInteger = 0
	Dim elements As String() = IPNumber.Split(New [Char]() {"."C})
	If elements.Length = 4 Then
		ip = Convert.ToUInt32(elements(0)) << 24
		ip += Convert.ToUInt32(elements(1)) << 16
		ip += Convert.ToUInt32(elements(2)) << 8
		ip += Convert.ToUInt32(elements(3))
	End If
	Return ip
End Function

Re: CIDR to Subnet in VB.NET2010

Hi,

Thanks for the code but what I wish to do is replicate the webpage in my original post. Jpye a CIDR, pre4ss the button for the result. That means no start address, no end address etc. If you look at the Javascript file it uses there are 3 functions and when trying to convert that to VB.NET I must be doing something wrong because on a /24 I am returning 64.64.64.0 not 255.255.255.0 and instead of returning the value to 4 textboxes like on that webpage, I wish to return as a string. As there are no Javascript to VB.NET convertors out there and my Java programming not being used for 12-14 years (Visual J++ in Visual Studio 98) I have made an error

In your example the start and the end IP's will be the same as I am not interested in using them whatsoever. That's why I gave a link to that page because this is EXACTLY what I wish to replicate. If you look at the comments in your example it says IP ADDRESS, SUBNET MASK, BROADCAST ADDRESS. I don't know the subnet as this is what I am wanting to calculate (see original post)

Any ideas on how I can achieve my original goal?

Re: CIDR to Subnet in VB.NET2010

Sorry I posted from related code, but not the correct one.

Try this one, it takes input 192.168.0.1/25 and outputs 192.168.0.1 - 192.168.0.126

IPAddress ip = new IPAddress(new byte[] { 192, 168, 0, 1 });
int bits = 25;

uint mask = ~(uint.MaxValue >> bits);

// Convert the IP address to bytes.
byte[] ipBytes = ip.GetAddressBytes();

// BitConverter gives bytes in opposite order to GetAddressBytes().
byte[] maskBytes = BitConverter.GetBytes(mask).Reverse().ToArray();

byte[] startIPBytes = new byte[ipBytes.Length];
byte[] endIPBytes = new byte[ipBytes.Length];

// Calculate the bytes of the start and end IP addresses.
for (int i = 0; i < ipBytes.Length; i++)
{
    startIPBytes[i] = (byte)(ipBytes[i] & maskBytes[i]);
    endIPBytes[i] = (byte)(ipBytes[i] | ~maskBytes[i]);
}

// Convert the bytes to IP addresses.
IPAddress startIP = new IPAddress(startIPBytes);
IPAddress endIP = new IPAddress(endIPBytes);

Re: CIDR to Subnet in VB.NET2010

Sorry whilst the above is again very close you what you want it isn't exactly what you asked for.

I believe that the below will do what you want. (shamelessly lifted from http://blogs.msdn.com/b/knom/archive/2008/12/31/ip-address-calculations-with-c-subnetmasks-networks.aspx)

  public static IPAddress CreateByHostBitLength(int hostpartLength)
    {
        int hostPartLength = hostpartLength;
        int netPartLength = 32 - hostPartLength;

        if (netPartLength < 2)
            throw new ArgumentException("Number of hosts is to large for IPv4");

        Byte[] binaryMask = new byte[4];

        for (int i = 0; i < 4; i++)
        {
            if (i * 8 + 8 <= netPartLength)
                binaryMask[i] = (byte)255;
            else if (i * 8 > netPartLength)
                binaryMask[i] = (byte)0;
            else {
                int oneLength = netPartLength - i * 8;
                string binaryDigit =
                    String.Empty.PadLeft(oneLength, '1').PadRight(8, '0');
                binaryMask[i] = Convert.ToByte(binaryDigit, 2);
            }
        }
        return new IPAddress(binaryMask);
    }

    public static IPAddress CreateByNetBitLength(int netpartLength)
    {
        int hostPartLength = 32 - netpartLength;
        return CreateByHostBitLength(hostPartLength);
    }

    public static IPAddress CreateByHostNumber(int numberOfHosts)
    {
        int maxNumber = numberOfHosts + 1;

        string b = Convert.ToString(maxNumber, 2);

        return CreateByHostBitLength(b.Length);
    }

Re: CIDR to Subnet in VB.NET2010

Hi, Thanks for the replay. I am not interested in calculating the range. Please click the link in my original post, look at the what it does then you'll see exatly what I am trying to do If you vie source, ctrl + f typing button you will see a javascript file link above. In that file are the 3 functions needed to do the conversion. I am trying to convert the calculations into vb.net Any ideas on code to replicate that webpage? Thanks in advance

Re: CIDR to Subnet in VB.NET2010

The C# code isn't what I am looking for. For instructions see my original post and my previous reply I want to be able to type '24' for example to return 255.255.255.0 etc

Re: CIDR to Subnet in VB.NET2010

something like this:

Public Function ConvertCIDRToMask(cidr As Integer) As String

        Dim ip As Int64 = Convert.ToInt64(New String("1"c, cidr).PadRight(32, "0"c), 2)
        Return (String.Join(".", New Net.IPAddress(ip).GetAddressBytes.Reverse))

    End Function

Re: CIDR to Subnet in VB.NET2010

Thanks Mike. That's exactly what I wanted and works perfectly.

Thank you also to the other contributors too