/// <summary>
/// Initializes a new instance of the <see cref="IPAddressRange"/> class,
/// representing a CIDR subnet.
/// </summary>
/// <param name="baseAddress">The base address of the subnet.</param>
/// <param name="prefixLength">The prefix length of the subnet.</param>
/// <exception cref="ArgumentNullException"><paramref name="baseAddress"/> is <see langword="null"/>.</exception>
/// <exception cref="ArgumentException">
/// <para><paramref name="prefixLength"/> is zero.</para>
/// <para>- or -</para>
/// <para><paramref name="prefixLength"/> is greater than the number of bits in
/// the binary representation of <paramref name="baseAddress"/> (32 for IPv4 addresses,
/// 128 for IPv6 addresses.)</para>
/// <para>- or -</para>
/// <para><paramref name="baseAddress"/> cannot be the base address of a subnet with a prefix length
/// equal to <paramref name="prefixLength"/>, because the remaining bits after the prefix
/// are not all zeros.</para>
/// </exception>
public IPAddressRange(IPAddress baseAddress, byte prefixLength)
{
if (baseAddress == null)
{
throw new ArgumentNullException(nameof(baseAddress));
}
byte maxPrefixLength;
if (baseAddress.AddressFamily == AddressFamily.InterNetworkV6)
{
_isV6 = true;
maxPrefixLength = 128;
}
else
{
_isV6 = false;
maxPrefixLength = 32;
}
if (prefixLength < 1 || prefixLength > maxPrefixLength)
{
throw InvalidPrefixLength(nameof(prefixLength));
}
_start = new IPAddressValue(baseAddress);
if (!_start.IsStartOfSubnet(prefixLength))
{
throw InvalidSubnetBaseAddress(nameof(baseAddress));
}
_end = _start.GetEndOfSubnet(prefixLength);
_prefixLength = prefixLength;
}
private static Exception?TryParseCidrOrAddressNetmaskFormat(string str, int separatorPos, out IPAddressRange result)
{
result = None;
var s = str.Substring(0, separatorPos).Trim();
if (!IPAddressUtility.TryParse(s, out var address))
{
return(InvalidIPAddress());
}
var addressValue = new IPAddressValue(address);
s = str.Substring(separatorPos + 1).Trim();
if (byte.TryParse(s, NumberStyles.None, CultureInfo.InvariantCulture, out var prefixLength))
{
var maxPrefixLength = address.AddressFamily == AddressFamily.InterNetworkV6 ? 128 : 32;
if (prefixLength < 1 || prefixLength > maxPrefixLength)
{
return(InvalidPrefixLength());
}
if (!addressValue.IsStartOfSubnet(prefixLength))
{
return(InvalidSubnetBaseAddress());
}
result = new IPAddressRange(addressValue, addressValue.GetEndOfSubnet(prefixLength), address.AddressFamily == AddressFamily.InterNetworkV6, prefixLength);
return(null);
}
// Only accept a netmask for IPv4
if (address.AddressFamily != AddressFamily.InterNetwork)
{
return(InvalidPrefixLength());
}
if (!IPAddressUtility.TryParse(s, out var netmask))
{
return(InvalidPrefixLengthOrNetmask());
}
var addressFamily = address.AddressFamily;
if (netmask.AddressFamily != addressFamily)
{
return(MismatchedNetmaskAddressFamily());
}
var netmaskBytes = netmask.GetAddressBytes();
if (!TryNetmaskToCidrPrefixLength(netmaskBytes, out prefixLength))
{
return(InvalidNetmask());
}
if (!addressValue.IsStartOfSubnet(prefixLength))
{
return(InvalidSubnetBaseAddress());
}
result = new IPAddressRange(addressValue, addressValue.GetEndOfSubnet(prefixLength), false, prefixLength);
return(null);
}