Table of Contents

Class IpNetwork

Namespace
VpnHood.Net.Toolkit.Net
Assembly
VpnHood.Net.Toolkit.dll

Represents an IP network in CIDR notation, such as 10.0.0.0/8 or 2001:db8::/32: a prefix, and the number of its leading bits that every address of the network shares.

[JsonConverter(typeof(IpNetworkConverter))]
public class IpNetwork
Inheritance
IpNetwork
Inherited Members

Remarks

Its properties are read-only, and the addresses they return are its own, which a caller must not change. The prefix is kept as given, host bits included, so 10.0.0.5/8 prints as such while its FirstIpAddress is 10.0.0.0; and two networks are equal when they hold the same addresses, so 10.0.0.5/8 equals 10.0.0.0/8.

A network of IPv4-mapped IPv6 addresses is the IPv4 network of those addresses, and is made so: ::ffff:10.0.0.0/104 is 10.0.0.0/8. A network that only reaches into the mapped addresses, as ::/80 does, is an IPv6 network like any other; and an address asked about is asked as its IPv4 address when it is mapped, which such a network does not hold.

JSON reads and writes a network as its text, through IpNetworkConverter.

Constructors

IpNetwork(IPAddress)

Initializes a new instance of the IpNetwork class that holds one address: a /32 for IPv4, a /128 for IPv6.

public IpNetwork(IPAddress prefix)

Parameters

prefix IPAddress

The address.

IpNetwork(IPAddress, int)

Initializes a new instance of the IpNetwork class.

public IpNetwork(IPAddress prefix, int prefixLength)

Parameters

prefix IPAddress

An address of the network. Its host bits are left out of the network's addresses but kept in Prefix.

prefixLength int

The number of leading bits the network's addresses share: 0 to 32 for IPv4, 0 to 128 for IPv6.

Remarks

An IPv4-mapped prefix with a length of 96 or more makes the IPv4 network of its IPv4 address, with a length 96 shorter.

Exceptions

ArgumentOutOfRangeException

prefixLength is negative, above 32 for an IPv4 prefix, or above 128 for an IPv6 one.

Properties

AddressFamily

Gets the network's address family: InterNetwork or InterNetworkV6.

public AddressFamily AddressFamily { get; }

Property Value

AddressFamily

All

Gets the networks of every address: AllV4 and AllV6.

public static IReadOnlyList<IpNetwork> All { get; }

Property Value

IReadOnlyList<IpNetwork>

AllGlobalUnicastV6

Gets the IPv6 global unicast space, 2000::/3, which holds every public IPv6 address assigned today.

public static IpNetwork AllGlobalUnicastV6 { get; }

Property Value

IpNetwork

AllV4

Gets the network of every IPv4 address, 0.0.0.0/0.

public static IpNetwork AllV4 { get; }

Property Value

IpNetwork

AllV6

Gets the network of every IPv6 address, ::/0.

public static IpNetwork AllV6 { get; }

Property Value

IpNetwork

FirstIpAddress

Gets the network's first address: the prefix with its host bits cleared.

public IPAddress FirstIpAddress { get; }

Property Value

IPAddress

IsV4

Gets whether the network is an IPv4 network.

public bool IsV4 { get; }

Property Value

bool

true if it is; otherwise, false.

IsV6

Gets whether the network is an IPv6 network.

public bool IsV6 { get; }

Property Value

bool

true if it is; otherwise, false.

LastIpAddress

Gets the network's last address: the prefix with its host bits set.

public IPAddress LastIpAddress { get; }

Property Value

IPAddress

LinkLocalNetworkV4

Gets the IPv4 link-local network, 169.254.0.0/16: the addresses an interface gives itself when no DHCP server answers (RFC 3927). They are never routed.

public static IpNetwork LinkLocalNetworkV4 { get; }

Property Value

IpNetwork

LinkLocalNetworkV6

Gets the IPv6 link-local network, fe80::/10, which every IPv6 interface has an address in, with no configuration. Its addresses are never routed.

public static IpNetwork LinkLocalNetworkV6 { get; }

Property Value

IpNetwork

LocalNetworks

Gets LocalNetworksV4 followed by LocalNetworksV6.

public static IReadOnlyList<IpNetwork> LocalNetworks { get; }

Property Value

IReadOnlyList<IpNetwork>

LocalNetworksV4

Gets the IPv4 networks of local networks: the private 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 (RFC 1918), and the link-local LinkLocalNetworkV4.

public static IReadOnlyList<IpNetwork> LocalNetworksV4 { get; }

Property Value

IReadOnlyList<IpNetwork>

Remarks

Neither the loopback network 127.0.0.0/8 nor the carriers' shared space 100.64.0.0/10 is in it: NonPublicNetworks holds every network that is not public.

LocalNetworksV6

Gets the IPv6 networks outside the global unicast space AllGlobalUnicastV6: ::/3, 4000::/2 and 8000::/1.

public static IReadOnlyList<IpNetwork> LocalNetworksV6 { get; }

Property Value

IReadOnlyList<IpNetwork>

Remarks

So it holds the loopback, unique local, link-local and multicast addresses, and the space no registry assigns yet, where LocalNetworksV4 holds the private and link-local networks alone.

LoopbackNetworkV4

Gets the IPv4 loopback network, 127.0.0.0/8.

public static IpNetwork LoopbackNetworkV4 { get; }

Property Value

IpNetwork

LoopbackNetworkV6

Gets the IPv6 loopback address as a network, ::1/128.

public static IpNetwork LoopbackNetworkV6 { get; }

Property Value

IpNetwork

LoopbackNetworks

Gets LoopbackNetworkV4 and LoopbackNetworkV6.

public static IReadOnlyList<IpNetwork> LoopbackNetworks { get; }

Property Value

IReadOnlyList<IpNetwork>

MulticastNetworkV4

Gets the IPv4 multicast network, 224.0.0.0/4.

public static IpNetwork MulticastNetworkV4 { get; }

Property Value

IpNetwork

MulticastNetworkV6

Gets the IPv6 multicast network, ff00::/8.

public static IpNetwork MulticastNetworkV6 { get; }

Property Value

IpNetwork

MulticastNetworks

Gets MulticastNetworkV4 and MulticastNetworkV6.

public static IReadOnlyList<IpNetwork> MulticastNetworks { get; }

Property Value

IReadOnlyList<IpNetwork>

NonPublicNetworks

Gets the networks of both families whose addresses are not public: those the registries set aside and do not count as reachable from the internet, the multicast networks, and every IPv6 address outside the global unicast space AllGlobalUnicastV6.

public static IReadOnlyList<IpNetwork> NonPublicNetworks { get; }

Property Value

IReadOnlyList<IpNetwork>

Remarks

It is the list for a guard that must keep a destination someone else names away from what only the machine or its network should reach: a server's own loopback, its local network, its provider's services. What a device takes as its local network is LocalNetworks.

IPv4: 0.0.0.0/8; the private 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16; the carriers' shared space 100.64.0.0/10; the loopback 127.0.0.0/8; the link-local 169.254.0.0/16; the protocol assignments 192.0.0.0/24; the documentation networks 192.0.2.0/24, 198.51.100.0/24 and 203.0.113.0/24; the benchmarking network 198.18.0.0/15; the multicast 224.0.0.0/4; and the reserved 240.0.0.0/4, the broadcast address with it.

IPv6: ::/3, 4000::/2 and 8000::/1, which hold the unspecified and loopback addresses, the NAT64 prefix 64:ff9b::/96, the unique local, link-local and multicast networks and the space no registry assigns yet; and, inside the global unicast space, Teredo's 2001::/32, the benchmarking network 2001:2::/48, the old ORCHID network 2001:10::/28, the documentation networks 2001:db8::/32 and 3fff::/20, and 6to4's 2002::/16.

The rest of the protocol assignments 2001::/23 is not in it, as the registry counts its other parts as reachable. The two anycast addresses it counts so inside 192.0.0.0/24 are not left out; and where a network translates the NAT64 prefix, its addresses stand for public IPv4 hosts all the same.

None

Gets an empty list of networks.

public static IReadOnlyList<IpNetwork> None { get; }

Property Value

IReadOnlyList<IpNetwork>

Prefix

Gets the address the network was made with, host bits included.

public IPAddress Prefix { get; }

Property Value

IPAddress

PrefixLength

Gets the number of leading bits the network's addresses share.

public int PrefixLength { get; }

Property Value

int

SubnetMask

Gets the subnet mask of the prefix length, such as 255.255.255.0 for a /24.

public IPAddress SubnetMask { get; }

Property Value

IPAddress

Exceptions

ArgumentOutOfRangeException

PrefixLength is negative.

Total

Gets the number of addresses in the network: 2 to the power of its host bits.

public BigInteger Total { get; }

Property Value

BigInteger

Methods

Contains(IPAddress)

Determines whether an address is in the network.

public bool Contains(IPAddress ipAddress)

Parameters

ipAddress IPAddress

The address. An IPv4-mapped IPv6 address is asked about as its IPv4 address, and a scope id is ignored.

Returns

bool

true if the network holds the address; otherwise, false.

Exceptions

ArgumentNullException

ipAddress is null.

Contains(IpAddressValue)

Determines whether an address is in the network, with no object made.

public bool Contains(IpAddressValue ipAddress)

Parameters

ipAddress IpAddressValue

The address. An IPv4-mapped IPv6 address is asked about as its IPv4 address, and a scope id is ignored; the default value is in no network.

Returns

bool

true if the network holds the address; otherwise, false.

Equals(object?)

Determines whether the specified object is equal to the current object.

public override bool Equals(object? obj)

Parameters

obj object

The object to compare with the current object.

Returns

bool

true if the specified object is equal to the current object; otherwise, false.

Remarks

Two networks are equal when they hold the same addresses; the prefix's host bits do not count.

FromRange(IPAddress, IPAddress)

Gets the fewest networks that hold exactly the addresses of a range.

public static IEnumerable<IpNetwork> FromRange(IPAddress firstIpAddress, IPAddress lastIpAddress)

Parameters

firstIpAddress IPAddress

The range's first address.

lastIpAddress IPAddress

The range's last address, of the same family.

Returns

IEnumerable<IpNetwork>

The networks, from the lowest address up; none when lastIpAddress is below firstIpAddress.

Remarks

The networks are made, and the families checked, as the result is enumerated. Two IPv4-mapped IPv6 addresses give the networks of their IPv4 addresses; a range that only reaches into the mapped addresses gives no network that lies wholly among them, as such a network holds no address a lookup asks about.

Exceptions

ArgumentException

The two addresses are of different families.

GetHashCode()

Serves as the default hash function.

public override int GetHashCode()

Returns

int

A hash code for the current object.

Invert()

Gets the networks of the addresses outside this network, within its own address family.

public IOrderedEnumerable<IpNetwork> Invert()

Returns

IOrderedEnumerable<IpNetwork>

The fewest networks that hold those addresses, from the lowest address up; none for a /0 network.

Parse(string)

Converts the text form of a network, such as 10.0.0.0/8, to an IpNetwork.

public static IpNetwork Parse(string value)

Parameters

value string

An address, a slash and a prefix length.

Returns

IpNetwork

The network.

Exceptions

FormatException

value is not an address, one slash and a prefix length of digits alone, or the length is above the family's bits.

ToIpRange()

Converts the network to the range from its first to its last address.

public IpRange ToIpRange()

Returns

IpRange

The range.

ToString()

Returns the network's text form: the prefix as given, a slash and the prefix length, such as 10.0.0.0/8.

public override string ToString()

Returns

string

The text.