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tailscale/net/netaddr/netaddr.go

91 lines
2.5 KiB
Go

// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package netaddr is a transitional package while we finish migrating from inet.af/netaddr
// to Go 1.18's net/netip.
//
// TODO(bradfitz): delete this package eventually. Tracking bug is
// https://github.com/tailscale/tailscale/issues/5162
package netaddr
import (
"math"
"net"
"net/netip"
)
// IPv4 returns the IP of the IPv4 address a.b.c.d.
func IPv4(a, b, c, d uint8) netip.Addr {
return netip.AddrFrom4([4]byte{a, b, c, d})
}
// IPFrom16 returns the IP address given by the bytes in addr, unmapping any
// v6-mapped IPv4 address.
//
// It is equivalent to calling IPv6Raw(addr).Unmap().
func IPFrom16(a [16]byte) netip.Addr {
return netip.AddrFrom16(a).Unmap()
}
// FromStdIP returns an IP from the standard library's IP type.
//
// If std is invalid, ok is false.
//
// FromStdIP implicitly unmaps IPv6-mapped IPv4 addresses. That is, if
// len(std) == 16 and contains an IPv4 address, only the IPv4 part is
// returned, without the IPv6 wrapper. This is the common form returned by
// the standard library's ParseIP: https://play.golang.org/p/qdjylUkKWxl.
// To convert a standard library IP without the implicit unmapping, use
// netip.AddrFromSlice.
func FromStdIP(std net.IP) (ip netip.Addr, ok bool) {
ret, ok := netip.AddrFromSlice(std)
if !ok {
return ret, false
}
if ret.Is4In6() {
return ret.Unmap(), true
}
return ret, true
}
// FromStdIPNet returns an IPPrefix from the standard library's IPNet type.
// If std is invalid, ok is false.
func FromStdIPNet(std *net.IPNet) (prefix netip.Prefix, ok bool) {
ip, ok := FromStdIP(std.IP)
if !ok {
return netip.Prefix{}, false
}
if l := len(std.Mask); l != net.IPv4len && l != net.IPv6len {
// Invalid mask.
return netip.Prefix{}, false
}
ones, bits := std.Mask.Size()
if ones == 0 && bits == 0 {
// IPPrefix does not support non-contiguous masks.
return netip.Prefix{}, false
}
return netip.PrefixFrom(ip, ones), true
}
// FromStdAddr maps the components of a standard library TCPAddr or
// UDPAddr into an IPPort.
func FromStdAddr(stdIP net.IP, port int, zone string) (_ netip.AddrPort, ok bool) {
ip, ok := FromStdIP(stdIP)
if !ok || port < 0 || port > math.MaxUint16 {
return
}
ip = ip.Unmap()
if zone != "" {
if ip.Is4() {
ok = false
return
}
ip = ip.WithZone(zone)
}
return netip.AddrPortFrom(ip, uint16(port)), true
}