How to subtract an IP address? ( both IPv4 and IPv6)

I have a requirement to get the number of IP addresses in an IP range identified by a startIP and an endIP both for IPv4 and IPv6 ranges.

Can anyone point to ways that can be used to achieve the subtraction of IP addresses?

开发者_开发知识库

The number of IP addresses will be = endIP - startIP + 1

Any responses are highly appreciated.

---

How's this?

class Program
{

    static void Main(string[] args)
    {
        IPAddress a = new IPAddress(new byte[] { 192, 168, 11, 12 });
        IPAddress b = new IPAddress(new byte[] { 192, 168, 12, 12 });
        long diff = Difference(a, b);
    }

    private static Int64 ConvertToLong(IPAddress a)
    {
        byte[] addressBits = a.GetAddressBytes();
        Int64 retval = 0;
        for (int i = 0; i < addressBits.Length; i++)
        {
            retval = (retval << 8) + (int)addressBits[i];
        }

        return retval;
    }

    private static Int64 Difference(IPAddress a, IPAddress b)
    {
        return Math.Abs(ConvertToLong(a) - ConvertToLong(b)) - 1;
    }

}

---

class Program          
{  
static void Main(string[] args)   
    {   
        string a = "192.168.11.12";
        string b = "192.168.12.12";
        int diff = Math.Abs(IPToInt(a) - IPToInt(b)) + 1;
    } 
int IPToInt(string IP) 
{ 
    return IPAddress.NetworkToHostOrder(BitConverter.ToInt32(IPAddress.Parse(IP).GetAddressBytes(), 0)); 
}       
}