ip.go

// Copyright (c) 2018-2021 The Decred developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.

package main

import "net/netip"

var (
	// rfc3964Net specifies the IPv6 to IPv4 encapsulation address block as
	// defined by RFC3964 (2002::/16).
	rfc3964Net = netip.MustParsePrefix("2002::/16")

	// rfc4380Net specifies the IPv6 teredo tunneling over UDP address block
	// as defined by RFC4380 (2001::/32).
	rfc4380Net = netip.MustParsePrefix("2001::/32")

	// rfc4843Net specifies the IPv6 ORCHID address block as defined by
	// RFC4843 (2001:10::/28).
	rfc4843Net = netip.MustParsePrefix("2001:10::/28")

	// rfc4862Net specifies the IPv6 stateless address autoconfiguration
	// address block as defined by RFC4862 (FE80::/64).
	rfc4862Net = netip.MustParsePrefix("FE80::/64")

	// rfc6598Net specifies the Carrier-Grade NAT address block as defined by
	// RFC6598 (100.64.0.0/10).
	rfc6598Net = netip.MustParsePrefix("100.64.0.0/10")
)

func isRoutable(addr netip.Addr) bool {
	if addr.IsLoopback() {
		return false
	}

	if addr.IsUnspecified() {
		return false
	}

	if addr.IsPrivate() {
		return false
	}

	if rfc3964Net.Contains(addr) ||
		rfc4380Net.Contains(addr) ||
		rfc4843Net.Contains(addr) ||
		rfc4862Net.Contains(addr) ||
		rfc6598Net.Contains(addr) {
		return false
	}

	return true
}