openethereum/util/network-devp2p/src/ip_utils.rs

// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of Open Ethereum.

// Open Ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Open Ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Open Ethereum.  If not, see <http://www.gnu.org/licenses/>.

// Based on original work by David Levy https://raw.githubusercontent.com/dlevy47/rust-interfaces

use std::io;
use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, SocketAddrV4, SocketAddrV6};
use std::time::Duration;

use igd::{PortMappingProtocol, search_gateway, SearchOptions};
use ipnetwork::IpNetwork;
use log::{trace, debug};
use natpmp::{Natpmp, Protocol, Response};
use network::NatType;

use crate::node_table::NodeEndpoint;

const NAT_PMP_PORT_MAPPING_LIFETIME: u32 = 30;
// Waiting duration in milliseconds for response from router after sending port mapping request.
// 50 milliseconds might be enough for low RTT.
const NAT_PMP_PORT_MAPPING_WAITING_DURATION: u64 = 50;

/// Socket address extension for rustc beta. To be replaces with now unstable API
pub trait SocketAddrExt {
	/// Returns true if the address appears to be globally routable.
	fn is_global_s(&self) -> bool;

	// Ipv4 specific
	fn is_shared_space(&self) -> bool { false }
	fn is_special_purpose(&self) -> bool { false }
	fn is_benchmarking(&self) -> bool { false }
	fn is_future_use(&self) -> bool { false }

	// Ipv6 specific
	fn is_unique_local_s(&self) -> bool { false }
	fn is_unicast_link_local_s(&self) -> bool { false }
	fn is_documentation_s(&self) -> bool { false }
	fn is_global_multicast(&self) -> bool { false }
	fn is_other_multicast(&self) -> bool { false }

	fn is_reserved(&self) -> bool;
	fn is_usable_public(&self) -> bool;
	fn is_usable_private(&self) -> bool;

	fn is_within(&self, ipnet: &IpNetwork) -> bool;
}

impl SocketAddrExt for Ipv4Addr {
	fn is_global_s(&self) -> bool {
		!self.is_private() &&
		!self.is_loopback() &&
		!self.is_link_local() &&
		!self.is_broadcast() &&
		!self.is_documentation()
	}

	// Used for communications between a service provider and its subscribers when using a carrier-grade NAT
	// see: https://en.wikipedia.org/wiki/Reserved_IP_addresses
	fn is_shared_space(&self) -> bool {
		*self >= Ipv4Addr::new(100, 64, 0, 0) &&
		*self <= Ipv4Addr::new(100, 127, 255, 255)
	}

	// Used for the IANA IPv4 Special Purpose Address Registry
	// see: https://en.wikipedia.org/wiki/Reserved_IP_addresses
	fn is_special_purpose(&self) -> bool {
		*self >= Ipv4Addr::new(192, 0, 0, 0) &&
		*self <= Ipv4Addr::new(192, 0, 0, 255)
	}

	// Used for testing of inter-network communications between two separate subnets
	// see: https://en.wikipedia.org/wiki/Reserved_IP_addresses
	fn is_benchmarking(&self) -> bool {
		*self >= Ipv4Addr::new(198, 18, 0, 0) &&
		*self <= Ipv4Addr::new(198, 19, 255, 255)
	}

	// Reserved for future use
	// see: https://en.wikipedia.org/wiki/Reserved_IP_addresses
	fn is_future_use(&self) -> bool {
		*self >= Ipv4Addr::new(240, 0, 0, 0) &&
		*self <= Ipv4Addr::new(255, 255, 255, 254)
	}

	fn is_reserved(&self) -> bool {
		self.is_unspecified() ||
		self.is_loopback() ||
		self.is_link_local() ||
		self.is_broadcast() ||
		self.is_documentation() ||
		self.is_multicast() ||
		self.is_shared_space() ||
		self.is_special_purpose() ||
		SocketAddrExt::is_benchmarking(self) ||
		self.is_future_use()
	}

	fn is_usable_public(&self) -> bool {
		!SocketAddrExt::is_reserved(self) &&
		!self.is_private()
	}

	fn is_usable_private(&self) -> bool {
		self.is_private()
	}

	fn is_within(&self, ipnet: &IpNetwork) -> bool {
		match ipnet {
			IpNetwork::V4(ipnet) => ipnet.contains(*self),
			_ => false
		}
	}
}

impl SocketAddrExt for Ipv6Addr {
	fn is_global_s(&self) -> bool {
		self.is_global_multicast() ||
		(!self.is_loopback() &&
		!self.is_unique_local_s() &&
		!self.is_unicast_link_local_s() &&
		!self.is_documentation_s() &&
		!self.is_other_multicast())
	}

	// unique local address (fc00::/7).
	fn is_unique_local_s(&self) -> bool {
		(self.segments()[0] & 0xfe00) == 0xfc00
	}

	// unicast and link-local (fe80::/10).
	fn is_unicast_link_local_s(&self) -> bool {
		(self.segments()[0] & 0xffc0) == 0xfe80
	}

	// reserved for documentation (2001:db8::/32).
	fn is_documentation_s(&self) -> bool {
		(self.segments()[0] == 0x2001) && (self.segments()[1] == 0xdb8)
	}

	fn is_global_multicast(&self) -> bool {
		self.segments()[0] & 0x000f == 14
	}

	fn is_other_multicast(&self) -> bool {
		self.is_multicast() && !self.is_global_multicast()
	}

	fn is_reserved(&self) -> bool {
		self.is_unspecified() ||
		self.is_loopback() ||
		self.is_unicast_link_local_s() ||
		self.is_documentation_s() ||
		self.is_other_multicast()
	}

	fn is_usable_public(&self) -> bool {
		!self.is_reserved() &&
		!self.is_unique_local_s()
	}

	fn is_usable_private(&self) -> bool {
		self.is_unique_local_s()
	}

	fn is_within(&self, ipnet: &IpNetwork) -> bool {
		match ipnet {
			IpNetwork::V6(ipnet) => ipnet.contains(*self),
			_ => false
		}
	}
}

impl SocketAddrExt for IpAddr {
	fn is_global_s(&self) -> bool {
		match *self {
			IpAddr::V4(ref ip) => ip.is_global_s(),
			IpAddr::V6(ref ip) => ip.is_global_s(),
		}
	}

	fn is_reserved(&self) -> bool {
		match *self {
			IpAddr::V4(ref ip) => SocketAddrExt::is_reserved(ip),
			IpAddr::V6(ref ip) => ip.is_reserved(),
		}
	}

	fn is_usable_public(&self) -> bool {
		match *self {
			IpAddr::V4(ref ip) => ip.is_usable_public(),
			IpAddr::V6(ref ip) => ip.is_usable_public(),
		}
	}

	fn is_usable_private(&self) -> bool {
		match *self {
			IpAddr::V4(ref ip) => ip.is_usable_private(),
			IpAddr::V6(ref ip) => ip.is_usable_private(),
		}
	}

	fn is_within(&self, ipnet: &IpNetwork) -> bool {
		match *self {
			IpAddr::V4(ref ip) => ip.is_within(ipnet),
			IpAddr::V6(ref ip) => ip.is_within(ipnet)
		}
	}
}

#[cfg(not(any(windows, target_os = "android")))]
mod getinterfaces {
	use std::{io, mem};
	use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};

	use libc::{AF_INET, AF_INET6};
	use libc::{freeifaddrs, getifaddrs, ifaddrs, sockaddr, sockaddr_in, sockaddr_in6};

	fn convert_sockaddr(sa: *mut sockaddr) -> Option<IpAddr> {
		if sa.is_null() { return None; }

		let (addr, _) = match i32::from(unsafe { *sa }.sa_family) {
			AF_INET => {
				let sa: *const sockaddr_in = sa as *const sockaddr_in;
				let sa = unsafe { &*sa };
				let (addr, port) = (sa.sin_addr.s_addr, sa.sin_port);
				// convert u32 to an `Ipv4 address`, but the u32 must be converted to `host-order`
				// that's why `from_be` is used!
				(IpAddr::V4(Ipv4Addr::from(<u32>::from_be(addr))), port)
			},
			AF_INET6 => {
				let sa: *const sockaddr_in6 = sa as *const sockaddr_in6;
				let sa = & unsafe { *sa };
				let (addr, port) = (sa.sin6_addr.s6_addr, sa.sin6_port);
				let ip_addr = Ipv6Addr::from(addr);
				debug_assert!(addr == ip_addr.octets());
				(IpAddr::V6(ip_addr), port)
			},
			_ => return None,
		};
		Some(addr)
	}

	fn convert_ifaddrs(ifa: *mut ifaddrs) -> Option<IpAddr> {
		let ifa = unsafe { &mut *ifa };
		convert_sockaddr(ifa.ifa_addr)
	}

	pub fn get_all() -> io::Result<Vec<IpAddr>> {
		let mut ifap: *mut ifaddrs = unsafe { mem::zeroed() };
		if unsafe { getifaddrs(&mut ifap as *mut _) } != 0 {
			return Err(io::Error::last_os_error());
		}

		let mut ret = Vec::new();
		let mut cur: *mut ifaddrs = ifap;
		while !cur.is_null() {
			if let Some(ip_addr) = convert_ifaddrs(cur) {
				ret.push(ip_addr);
			}

			//TODO: do something else maybe?
			cur = unsafe { (*cur).ifa_next };
		}

		unsafe { freeifaddrs(ifap) };
		Ok(ret)
	}
}

#[cfg(not(any(windows, target_os = "android")))]
fn get_if_addrs() -> io::Result<Vec<IpAddr>> {
	getinterfaces::get_all()
}

#[cfg(any(windows, target_os = "android"))]
fn get_if_addrs() -> io::Result<Vec<IpAddr>> {
	Ok(Vec::new())
}

/// Select the best available public address
pub fn select_public_address(port: u16) -> SocketAddr {
	match get_if_addrs() {
		Ok(list) => {
			//prefer IPV4 bindings
			for addr in &list { //TODO: use better criteria than just the first in the list
				match addr {
					IpAddr::V4(a) if !SocketAddrExt::is_reserved(a) => {
						return SocketAddr::V4(SocketAddrV4::new(*a, port));
					},
					_ => {},
				}
			}
			for addr in &list {
				match addr {
					IpAddr::V6(a) if !a.is_reserved() => {
						return SocketAddr::V6(SocketAddrV6::new(*a, port, 0, 0));
					},
					_ => {},
				}
			}
		},
		Err(e) => debug!("Error listing public interfaces: {:?}", e)
	}
	SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), port))
}

fn search_upnp(local: &NodeEndpoint) -> Option<NodeEndpoint> {
	if let SocketAddr::V4(ref local_addr) = local.address {
		let local_ip = *local_addr.ip();
		let local_port = local_addr.port();
		let local_udp_port = local.udp_port;

		let search_options = SearchOptions {
			timeout: Some(Duration::new(5, 0)),
			// igd 0.7 used port 0 by default.
			// Let's not change this behaviour
			bind_addr: SocketAddr::V4(SocketAddrV4::new(local_ip, 0)),
			..Default::default()
		};
		let search_gateway_child = ::std::thread::spawn(move || {
			match search_gateway(search_options) {
				Err(ref err) => debug!("Gateway search error: {}", err),
				Ok(gateway) => {
					match gateway.get_external_ip() {
						Err(ref err) => {
							debug!("IP request error: {}", err);
						},
						Ok(external_addr) => {
							match gateway.add_any_port(PortMappingProtocol::TCP, SocketAddrV4::new(local_ip, local_port), 0, "Parity Node/TCP") {
								Err(ref err) => {
									debug!("Port mapping error: {}", err);
								},
								Ok(tcp_port) => {
									match gateway.add_any_port(PortMappingProtocol::UDP, SocketAddrV4::new(local_ip, local_udp_port), 0, "Parity Node/UDP") {
										Err(ref err) => {
											debug!("Port mapping error: {}", err);
										},
										Ok(udp_port) => {
											return Some(NodeEndpoint { address: SocketAddr::V4(SocketAddrV4::new(external_addr, tcp_port)), udp_port });
										},
									}
								},
							}
						},
					}
				},
			}
			None
		});
		return search_gateway_child.join().ok()?;
	}
	None
}

fn search_natpmp(local: &NodeEndpoint) -> Option<NodeEndpoint> {
	if let SocketAddr::V4(ref local_addr) = local.address {
		let local_port = local_addr.port();
		let local_udp_port = local.udp_port;

		let search_gateway_child = ::std::thread::spawn(move || {
			let mut n = Natpmp::new()?;

			// this function call want to receive `Response::Gateway` response from router, if other then it is an Error.
			n.send_public_address_request()?;
			::std::thread::sleep(Duration::from_millis(NAT_PMP_PORT_MAPPING_WAITING_DURATION));
			let gw = match n.read_response_or_retry() {
				Ok(Response::Gateway(gw)) => Ok(gw),
				Err(e) => {
					debug!(target: "network", "IP request error: {}", e);
					Err(e)
				},
				_ => Err(natpmp::Error::NATPMP_ERR_UNDEFINEDERROR.into())
			}?;

			// this function call want to receive `Response::TCP` response from router, if other then it is an Error.
			n.send_port_mapping_request(Protocol::TCP, local_port, local_port, NAT_PMP_PORT_MAPPING_LIFETIME)?;
			::std::thread::sleep(Duration::from_millis(NAT_PMP_PORT_MAPPING_WAITING_DURATION));
			let tcp_r = match n.read_response_or_retry() {
				Ok(Response::TCP(tcp)) => Ok(tcp),
				Err(e) => {
					debug!(target: "network", "Port mapping for TCP error: {}", e);
					Err(e)
				},
				_ => Err(natpmp::Error::NATPMP_ERR_UNDEFINEDERROR.into())
			}?;

			// this function call want to receive `Response::UDP` response from router, if other then it is an Error.
			n.send_port_mapping_request(Protocol::UDP, local_udp_port, local_udp_port, NAT_PMP_PORT_MAPPING_LIFETIME)?;
			::std::thread::sleep(Duration::from_millis(NAT_PMP_PORT_MAPPING_WAITING_DURATION));
			let udp_r = match n.read_response_or_retry() {
				Ok(Response::UDP(udp)) => Ok(udp),
				Err(e) => {
					debug!(target: "network", "Port mapping for UDP error: {}", e);
					Err(e)
				},
				_ => Err(natpmp::Error::NATPMP_ERR_UNDEFINEDERROR.into())
			}?;

			Ok(NodeEndpoint {
				address: SocketAddr::V4(SocketAddrV4::new(*gw.public_address(), tcp_r.public_port())),
				udp_port: udp_r.public_port()
			})
		});

		return search_gateway_child.join().ok()?
			.map_err(|e: natpmp::Error| debug!(target: "network", "NAT PMP port mapping error: {:?}", e))
			.ok();
	}
	None
}

/// Port mapping using ether UPnP or Nat-PMP.
/// NAT PMP has higher priority than UPnP.
pub fn map_external_address(local: &NodeEndpoint, nat_type: &NatType) -> Option<NodeEndpoint> {
	match *nat_type {
		NatType::Any => {
			match search_natpmp(local) {
				Some(end_point) => Some(end_point),
				None => search_upnp(local),
			}
		},
		NatType::NatPMP => search_natpmp(local),
		NatType::UPnP => search_upnp(local),
		_ => {
			trace!(target: "network", "Can't map external address using NAT");
			None
		}
	}
}

#[test]
fn can_select_public_address() {
	let pub_address = select_public_address(40477);
	assert!(pub_address.port() == 40477);
}

#[ignore]
#[test]
fn can_map_external_address_upnp_or_fail() {
	let pub_address = select_public_address(40478);
	let _ = map_external_address(&NodeEndpoint { address: pub_address, udp_port: 40478 }, &NatType::UPnP);
}

#[ignore]
#[test]
fn can_map_external_address_natpmp_or_fail() {
	let pub_address = select_public_address(40479);
	let _ = map_external_address(&NodeEndpoint { address: pub_address, udp_port: 40479 }, &NatType::NatPMP);
}

#[test]
fn ipv4_properties() {
	fn check(octets: &[u8; 4], unspec: bool, loopback: bool,
			 private: bool, link_local: bool, global: bool,
			 multicast: bool, broadcast: bool, documentation: bool) {
		let ip = Ipv4Addr::new(octets[0], octets[1], octets[2], octets[3]);
		assert_eq!(octets, &ip.octets());

		assert_eq!(ip.is_unspecified(), unspec);
		assert_eq!(ip.is_loopback(), loopback);
		assert_eq!(ip.is_private(), private);
		assert_eq!(ip.is_link_local(), link_local);
		assert_eq!(ip.is_global_s(), global);
		assert_eq!(ip.is_multicast(), multicast);
		assert_eq!(ip.is_broadcast(), broadcast);
		assert_eq!(ip.is_documentation(), documentation);
	}

	//    address                unspec loopbk privt  linloc global multicast brdcast doc
	check(&[0, 0, 0, 0],         true,  false, false, false, true,  false,    false,  false);
	check(&[0, 0, 0, 1],         false, false, false, false, true,  false,    false,  false);
	check(&[1, 0, 0, 0],         false, false, false, false, true,  false,    false,  false);
	check(&[10, 9, 8, 7],        false, false, true,  false, false, false,    false,  false);
	check(&[127, 1, 2, 3],       false, true,  false, false, false, false,    false,  false);
	check(&[172, 31, 254, 253],  false, false, true,  false, false, false,    false,  false);
	check(&[169, 254, 253, 242], false, false, false, true,  false, false,    false,  false);
	check(&[192, 0, 2, 183],     false, false, false, false, false, false,    false,  true);
	check(&[192, 1, 2, 183],     false, false, false, false, true,  false,    false,  false);
	check(&[192, 168, 254, 253], false, false, true,  false, false, false,    false,  false);
	check(&[198, 51, 100, 0],    false, false, false, false, false, false,    false,  true);
	check(&[203, 0, 113, 0],     false, false, false, false, false, false,    false,  true);
	check(&[203, 2, 113, 0],     false, false, false, false, true,  false,    false,  false);
	check(&[224, 0, 0, 0],       false, false, false, false, true,  true,     false,  false);
	check(&[239, 255, 255, 255], false, false, false, false, true,  true,     false,  false);
	check(&[255, 255, 255, 255], false, false, false, false, false, false,    true,   false);
}

#[test]
fn ipv4_shared_space() {
	assert!(!Ipv4Addr::new(100, 63, 255, 255).is_shared_space());
	assert!(Ipv4Addr::new(100, 64, 0, 0).is_shared_space());
	assert!(Ipv4Addr::new(100, 127, 255, 255).is_shared_space());
	assert!(!Ipv4Addr::new(100, 128, 0, 0).is_shared_space());
}

#[test]
fn ipv4_special_purpose() {
	assert!(!Ipv4Addr::new(191, 255, 255, 255).is_special_purpose());
	assert!(Ipv4Addr::new(192, 0, 0, 0).is_special_purpose());
	assert!(Ipv4Addr::new(192, 0, 0, 255).is_special_purpose());
	assert!(!Ipv4Addr::new(192, 0, 1, 255).is_special_purpose());
}

#[test]
fn ipv4_benchmarking() {
	assert!(!SocketAddrExt::is_benchmarking(&Ipv4Addr::new(198, 17, 255, 255)));
	assert!(SocketAddrExt::is_benchmarking(&Ipv4Addr::new(198, 18, 0, 0)));
	assert!(SocketAddrExt::is_benchmarking(&Ipv4Addr::new(198, 19, 255, 255)));
	assert!(!SocketAddrExt::is_benchmarking(&Ipv4Addr::new(198, 20, 0, 0)));
}

#[test]
fn ipv4_future_use() {
	assert!(!Ipv4Addr::new(239, 255, 255, 255).is_future_use());
	assert!(Ipv4Addr::new(240, 0, 0, 0).is_future_use());
	assert!(Ipv4Addr::new(255, 255, 255, 254).is_future_use());
	assert!(!Ipv4Addr::new(255, 255, 255, 255).is_future_use());
}

#[test]
fn ipv4_usable_public() {
	assert!(!Ipv4Addr::new(0,0,0,0).is_usable_public()); // unspecified
	assert!(Ipv4Addr::new(0,0,0,1).is_usable_public());

	assert!(Ipv4Addr::new(9,255,255,255).is_usable_public());
	assert!(!Ipv4Addr::new(10,0,0,0).is_usable_public()); // private intra-network
	assert!(!Ipv4Addr::new(10,255,255,255).is_usable_public()); // private intra-network
	assert!(Ipv4Addr::new(11,0,0,0).is_usable_public());

	assert!(Ipv4Addr::new(100, 63, 255, 255).is_usable_public());
	assert!(!Ipv4Addr::new(100, 64, 0, 0).is_usable_public()); // shared space
	assert!(!Ipv4Addr::new(100, 127, 255, 255).is_usable_public()); // shared space
	assert!(Ipv4Addr::new(100, 128, 0, 0).is_usable_public());

	assert!(Ipv4Addr::new(126,255,255,255).is_usable_public());
	assert!(!Ipv4Addr::new(127,0,0,0).is_usable_public()); // loopback
	assert!(!Ipv4Addr::new(127,255,255,255).is_usable_public()); // loopback
	assert!(Ipv4Addr::new(128,0,0,0).is_usable_public());

	assert!(Ipv4Addr::new(169,253,255,255).is_usable_public());
	assert!(!Ipv4Addr::new(169,254,0,0).is_usable_public()); // link-local
	assert!(!Ipv4Addr::new(169,254,255,255).is_usable_public()); // link-local
	assert!(Ipv4Addr::new(169,255,0,0).is_usable_public());

	assert!(Ipv4Addr::new(172,15,255,255).is_usable_public());
	assert!(!Ipv4Addr::new(172,16,0,0).is_usable_public()); // private intra-network
	assert!(!Ipv4Addr::new(172,31,255,255).is_usable_public()); // private intra-network
	assert!(Ipv4Addr::new(172,32,255,255).is_usable_public());

	assert!(Ipv4Addr::new(191,255,255,255).is_usable_public());
	assert!(!Ipv4Addr::new(192,0,0,0).is_usable_public()); // special purpose
	assert!(!Ipv4Addr::new(192,0,0,255).is_usable_public()); // special purpose
	assert!(Ipv4Addr::new(192,0,1,0).is_usable_public());

	assert!(Ipv4Addr::new(192,0,1,255).is_usable_public());
	assert!(!Ipv4Addr::new(192,0,2,0).is_usable_public()); // documentation
	assert!(!Ipv4Addr::new(192,0,2,255).is_usable_public()); // documentation
	assert!(Ipv4Addr::new(192,0,3,0).is_usable_public());

	assert!(Ipv4Addr::new(192,167,255,255).is_usable_public());
	assert!(!Ipv4Addr::new(192,168,0,0).is_usable_public()); // private intra-network
	assert!(!Ipv4Addr::new(192,168,255,255).is_usable_public()); // private intra-network
	assert!(Ipv4Addr::new(192,169,0,0).is_usable_public());

	assert!(Ipv4Addr::new(198,17,255,255).is_usable_public());
	assert!(!Ipv4Addr::new(198,18,0,0).is_usable_public()); // benchmarking
	assert!(!Ipv4Addr::new(198,19,255,255).is_usable_public()); // benchmarking
	assert!(Ipv4Addr::new(198,20,0,0).is_usable_public());

	assert!(Ipv4Addr::new(198,51,99,255).is_usable_public());
	assert!(!Ipv4Addr::new(198,51,100,0).is_usable_public()); // documentation
	assert!(!Ipv4Addr::new(198,51,100,255).is_usable_public()); // documentation
	assert!(Ipv4Addr::new(198,51,101,0).is_usable_public());

	assert!(Ipv4Addr::new(203,0,112,255).is_usable_public());
	assert!(!Ipv4Addr::new(203,0,113,0).is_usable_public()); // documentation
	assert!(!Ipv4Addr::new(203,0,113,255).is_usable_public()); // documentation
	assert!(Ipv4Addr::new(203,0,114,0).is_usable_public());

	assert!(Ipv4Addr::new(223,255,255,255).is_usable_public());
	assert!(!Ipv4Addr::new(224,0,0,0).is_usable_public()); // multicast
	assert!(!Ipv4Addr::new(239, 255, 255, 255).is_usable_public()); // multicast
	assert!(!Ipv4Addr::new(240, 0, 0, 0).is_usable_public()); // future use
	assert!(!Ipv4Addr::new(255, 255, 255, 254).is_usable_public()); // future use
	assert!(!Ipv4Addr::new(255, 255, 255, 255).is_usable_public()); // limited broadcast
}

#[test]
fn ipv4_usable_private() {
	assert!(!Ipv4Addr::new(9,255,255,255).is_usable_private());
	assert!(Ipv4Addr::new(10,0,0,0).is_usable_private()); // private intra-network
	assert!(Ipv4Addr::new(10,255,255,255).is_usable_private()); // private intra-network
	assert!(!Ipv4Addr::new(11,0,0,0).is_usable_private());

	assert!(!Ipv4Addr::new(172,15,255,255).is_usable_private());
	assert!(Ipv4Addr::new(172,16,0,0).is_usable_private()); // private intra-network
	assert!(Ipv4Addr::new(172,31,255,255).is_usable_private()); // private intra-network
	assert!(!Ipv4Addr::new(172,32,255,255).is_usable_private());

	assert!(!Ipv4Addr::new(192,167,255,255).is_usable_private());
	assert!(Ipv4Addr::new(192,168,0,0).is_usable_private()); // private intra-network
	assert!(Ipv4Addr::new(192,168,255,255).is_usable_private()); // private intra-network
	assert!(!Ipv4Addr::new(192,169,0,0).is_usable_private());
}

#[test]
fn ipv6_properties() {
	fn check(str_addr: &str, unspec: bool, loopback: bool, global: bool) {
		let ip: Ipv6Addr = str_addr.parse().unwrap();
		assert_eq!(str_addr, ip.to_string());

		assert_eq!(ip.is_unspecified(), unspec);
		assert_eq!(ip.is_loopback(), loopback);
		assert_eq!(ip.is_global_s(), global);
	}

	//    unspec loopbk global
	check("::", true,  false, true);
	check("::1", false, true, false);
}