using System;
using System.Net;
using System.Net.Sockets;
namespace MediaBrowser.Common.Net
{
/// <summary>
/// Base network object class.
/// </summary>
public abstract class IPObject : IEquatable<IPObject>
{
/// <summary>
/// The network address of this object.
/// </summary>
private IPObject? _networkAddress;
/// <summary>
/// Gets or sets a user defined value that is associated with this object.
/// </summary>
public int Tag { get; set; }
/// <summary>
/// Gets or sets the object's IP address.
/// </summary>
public abstract IPAddress Address { get; set; }
/// <summary>
/// Gets the object's network address.
/// </summary>
public IPObject NetworkAddress => _networkAddress ??= CalculateNetworkAddress();
/// <summary>
/// Gets or sets the object's IP address.
/// </summary>
public abstract byte PrefixLength { get; set; }
/// <summary>
/// Gets the AddressFamily of this object.
/// </summary>
public AddressFamily AddressFamily
{
get
{
// Keep terms separate as Address performs other functions in inherited objects.
IPAddress address = Address;
return address.Equals(IPAddress.None) ? AddressFamily.Unspecified : address.AddressFamily;
}
}
/// <summary>
/// Returns the network address of an object.
/// </summary>
/// <param name="address">IP Address to convert.</param>
/// <param name="prefixLength">Subnet prefix.</param>
/// <returns>IPAddress.</returns>
public static (IPAddress address, byte prefixLength) NetworkAddressOf(IPAddress address, byte prefixLength)
{
if (address == null)
{
throw new ArgumentNullException(nameof(address));
}
if (address.IsIPv4MappedToIPv6)
{
address = address.MapToIPv4();
}
if (IsLoopback(address))
{
return (address, prefixLength);
}
// An ip address is just a list of bytes, each one representing a segment on the network.
// This separates the IP address into octets and calculates how many octets will need to be altered or set to zero dependant upon the
// prefix length value. eg. /16 on a 4 octet ip4 address (192.168.2.240) will result in the 2 and the 240 being zeroed out.
// Where there is not an exact boundary (eg /23), mod is used to calculate how many bits of this value are to be kept.
// GetAddressBytes
Span<byte> addressBytes = stackalloc byte[address.AddressFamily == AddressFamily.InterNetwork ? 4 : 16];
address.TryWriteBytes(addressBytes, out _);
int div = prefixLength / 8;
int mod = prefixLength % 8;
if (mod != 0)
{
// Prefix length is counted right to left, so subtract 8 so we know how many bits to clear.
mod = 8 - mod;
// Shift out the bits from the octet that we don't want, by moving right then back left.
addressBytes[div] = (byte)((int)addressBytes[div] >> mod << mod);
// Move on the next byte.
div++;
}
// Blank out the remaining octets from mod + 1 to the end of the byte array. (192.168.2.240/16 becomes 192.168.0.0)
for (int octet = div; octet < addressBytes.Length; octet++)
{
addressBytes[octet] = 0;
}
// Return the network address for the prefix.
return (new IPAddress(addressBytes), prefixLength);
}
/// <summary>
/// Tests to see if the ip address is a Loopback address.
/// </summary>
/// <param name="address">Value to test.</param>
/// <returns>True if it is.</returns>
public static bool IsLoopback(IPAddress address)
{
if (address == null)
{
throw new ArgumentNullException(nameof(address));
}
if (!address.Equals(IPAddress.None))
{
if (address.IsIPv4MappedToIPv6)
{
address = address.MapToIPv4();
}
return address.Equals(IPAddress.Loopback) || address.Equals(IPAddress.IPv6Loopback);
}
return false;
}
/// <summary>
/// Tests to see if the ip address is an IP6 address.
/// </summary>
/// <param name="address">Value to test.</param>
/// <returns>True if it is.</returns>
public static bool IsIP6(IPAddress address)
{
if (address == null)
{
throw new ArgumentNullException(nameof(address));
}
if (address.IsIPv4MappedToIPv6)
{
address = address.MapToIPv4();
}
return !address.Equals(IPAddress.None) && (address.AddressFamily == AddressFamily.InterNetworkV6);
}
/// <summary>
/// Tests to see if the address in the private address range.
/// </summary>
/// <param name="address">Object to test.</param>
/// <returns>True if it contains a private address.</returns>
public static bool IsPrivateAddressRange(IPAddress address)
{
if (address == null)
{
throw new ArgumentNullException(nameof(address));
}
if (!address.Equals(IPAddress.None))
{
if (address.IsIPv4MappedToIPv6)
{
address = address.MapToIPv4();
}
if (address.AddressFamily == AddressFamily.InterNetwork)
{
// GetAddressBytes
Span<byte> octet = stackalloc byte[4];
address.TryWriteBytes(octet, out _);
return (octet[0] == 10)
|| (octet[0] == 172 && octet[1] >= 16 && octet[1] <= 31) // RFC1918
|| (octet[0] == 192 && octet[1] == 168) // RFC1918
|| (octet[0] == 127); // RFC1122
}
else
{
// GetAddressBytes
Span<byte> octet = stackalloc byte[16];
address.TryWriteBytes(octet, out _);
uint word = (uint)(octet[0] << 8) + octet[1];
return (word >= 0xfe80 && word <= 0xfebf) // fe80::/10 :Local link.
|| (word >= 0xfc00 && word <= 0xfdff); // fc00::/7 :Unique local address.
}
}
return false;
}
/// <summary>
/// Returns true if the IPAddress contains an IP6 Local link address.
/// </summary>
/// <param name="address">IPAddress object to check.</param>
/// <returns>True if it is a local link address.</returns>
/// <remarks>
/// See https://stackoverflow.com/questions/6459928/explain-the-instance-properties-of-system-net-ipaddress
/// it appears that the IPAddress.IsIPv6LinkLocal is out of date.
/// </remarks>
public static bool IsIPv6LinkLocal(IPAddress address)
{
if (address == null)
{
throw new ArgumentNullException(nameof(address));
}
if (address.IsIPv4MappedToIPv6)
{
address = address.MapToIPv4();
}
if (address.AddressFamily != AddressFamily.InterNetworkV6)
{
return false;
}
// GetAddressBytes
Span<byte> octet = stackalloc byte[16];
address.TryWriteBytes(octet, out _);
uint word = (uint)(octet[0] << 8) + octet[1];
return word >= 0xfe80 && word <= 0xfebf; // fe80::/10 :Local link.
}
/// <summary>
/// Convert a subnet mask in CIDR notation to a dotted decimal string value. IPv4 only.
/// </summary>
/// <param name="cidr">Subnet mask in CIDR notation.</param>
/// <param name="family">IPv4 or IPv6 family.</param>
/// <returns>String value of the subnet mask in dotted decimal notation.</returns>
public static IPAddress CidrToMask(byte cidr, AddressFamily family)
{
uint addr = 0xFFFFFFFF << (family == AddressFamily.InterNetwork ? 32 : 128 - cidr);
addr = ((addr & 0xff000000) >> 24)
| ((addr & 0x00ff0000) >> 8)
| ((addr & 0x0000ff00) << 8)
| ((addr & 0x000000ff) << 24);
return new IPAddress(addr);
}
/// <summary>
/// Convert a mask to a CIDR. IPv4 only.
/// https://stackoverflow.com/questions/36954345/get-cidr-from-netmask.
/// </summary>
/// <param name="mask">Subnet mask.</param>
/// <returns>Byte CIDR representing the mask.</returns>
public static byte MaskToCidr(IPAddress mask)
{
if (mask == null)
{
throw new ArgumentNullException(nameof(mask));
}
byte cidrnet = 0;
if (!mask.Equals(IPAddress.Any))
{
// GetAddressBytes
Span<byte> bytes = stackalloc byte[mask.AddressFamily == AddressFamily.InterNetwork ? 4 : 16];
mask.TryWriteBytes(bytes, out _);
var zeroed = false;
for (var i = 0; i < bytes.Length; i++)
{
for (int v = bytes[i]; (v & 0xFF) != 0; v <<= 1)
{
if (zeroed)
{
// Invalid netmask.
return (byte)~cidrnet;
}
if ((v & 0x80) == 0)
{
zeroed = true;
}
else
{
cidrnet++;
}
}
}
}
return cidrnet;
}
/// <summary>
/// Tests to see if this object is a Loopback address.
/// </summary>
/// <returns>True if it is.</returns>
public virtual bool IsLoopback()
{
return IsLoopback(Address);
}
/// <summary>
/// Removes all addresses of a specific type from this object.
/// </summary>
/// <param name="family">Type of address to remove.</param>
public virtual void Remove(AddressFamily family)
{
// This method only performs a function in the IPHost implementation of IPObject.
}
/// <summary>
/// Tests to see if this object is an IPv6 address.
/// </summary>
/// <returns>True if it is.</returns>
public virtual bool IsIP6()
{
return IsIP6(Address);
}
/// <summary>
/// Returns true if this IP address is in the RFC private address range.
/// </summary>
/// <returns>True this object has a private address.</returns>
public virtual bool IsPrivateAddressRange()
{
return IsPrivateAddressRange(Address);
}
/// <summary>
/// Compares this to the object passed as a parameter.
/// </summary>
/// <param name="ip">Object to compare to.</param>
/// <returns>Equality result.</returns>
public virtual bool Equals(IPAddress ip)
{
if (ip != null)
{
if (ip.IsIPv4MappedToIPv6)
{
ip = ip.MapToIPv4();
}
return !Address.Equals(IPAddress.None) && Address.Equals(ip);
}
return false;
}
/// <summary>
/// Compares this to the object passed as a parameter.
/// </summary>
/// <param name="other">Object to compare to.</param>
/// <returns>Equality result.</returns>
public virtual bool Equals(IPObject? other)
{
if (other != null)
{
return !Address.Equals(IPAddress.None) && Address.Equals(other.Address);
}
return false;
}
/// <summary>
/// Compares the address in this object and the address in the object passed as a parameter.
/// </summary>
/// <param name="address">Object's IP address to compare to.</param>
/// <returns>Comparison result.</returns>
public abstract bool Contains(IPObject address);
/// <summary>
/// Compares the address in this object and the address in the object passed as a parameter.
/// </summary>
/// <param name="address">Object's IP address to compare to.</param>
/// <returns>Comparison result.</returns>
public abstract bool Contains(IPAddress address);
/// <inheritdoc/>
public override int GetHashCode()
{
return Address.GetHashCode();
}
/// <inheritdoc/>
public override bool Equals(object? obj)
{
return Equals(obj as IPObject);
}
/// <summary>
/// Calculates the network address of this object.
/// </summary>
/// <returns>Returns the network address of this object.</returns>
protected abstract IPObject CalculateNetworkAddress();
}
}