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// Copyright 2020 The Inet.Af 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 netipx contains code and types that were left behind when
// the old inet.af/netaddr package moved to the standard library in Go
// 1.18 as net/netip.
package netipx // import "go4.org/netipx"
import (
"errors"
"fmt"
"math"
"net"
"net/netip"
"sort"
"strings"
)
// 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)
return ret.Unmap(), ok
}
// MustFromStdIP is like FromStdIP, but it panics if std is invalid.
func MustFromStdIP(std net.IP) netip.Addr {
ret, ok := netip.AddrFromSlice(std)
if !ok {
panic("not a valid IP address")
}
return ret.Unmap()
}
// FromStdIPRaw returns an IP from the standard library's IP type.
// If std is invalid, ok is false.
// Unlike FromStdIP, FromStdIPRaw does not do an implicit Unmap if
// len(std) == 16 and contains an IPv6-mapped IPv4 address.
//
// Deprecated: use netip.AddrFromSlice instead.
func FromStdIPRaw(std net.IP) (ip netip.Addr, ok bool) {
return netip.AddrFromSlice(std)
}
// ParsePrefixOrAddr parses s as an IP address prefix or IP address. If s parses
// as an IP address prefix, its [net/netip.Prefix.Addr] is returned. The string
// s can be an IPv4 address ("192.0.2.1"), IPv6 address ("2001:db8::68"), IPv4
// prefix ("192.0.2.1/32"), or IPv6 prefix ("2001:db:68/96").
func ParsePrefixOrAddr(s string) (netip.Addr, error) {
// Factored out of netip.ParsePrefix to avoid allocating an empty netip.Prefix in case it's
// an address and not a prefix.
i := strings.LastIndexByte(s, '/')
if i < 0 {
return netip.ParseAddr(s)
}
prefix, err := netip.ParsePrefix(s)
return prefix.Addr(), err
}
// AddrNext returns the IP following ip.
// If there is none, it returns the IP zero value.
//
// Deprecated: use netip.Addr.Next instead.
func AddrNext(ip netip.Addr) netip.Addr {
addr := u128From16(ip.As16()).addOne()
if ip.Is4() {
if uint32(addr.lo) == 0 {
// Overflowed.
return netip.Addr{}
}
return addr.IP4()
} else {
if addr.isZero() {
// Overflowed
return netip.Addr{}
}
return addr.IP6().WithZone(ip.Zone())
}
}
// AddrPrior returns the IP before ip.
// If there is none, it returns the IP zero value.
//
// Deprecated: use netip.Addr.Prev instead.
func AddrPrior(ip netip.Addr) netip.Addr {
addr := u128From16(ip.As16())
if ip.Is4() {
if uint32(addr.lo) == 0 {
return netip.Addr{}
}
return addr.subOne().IP4()
} else {
if addr.isZero() {
return netip.Addr{}
}
return addr.subOne().IP6().WithZone(ip.Zone())
}
}
// 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 netip.AddrPort{}, false
}
ip = ip.Unmap()
if zone != "" {
if ip.Is4() {
ok = false
return
}
ip = ip.WithZone(zone)
}
return netip.AddrPortFrom(ip, uint16(port)), true
}
// FromStdIPNet returns an netip.Prefix 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
}
// RangeOfPrefix returns the inclusive range of IPs that p covers.
//
// If p is zero or otherwise invalid, Range returns the zero value.
func RangeOfPrefix(p netip.Prefix) IPRange {
p = p.Masked()
if !p.IsValid() {
return IPRange{}
}
return IPRangeFrom(p.Addr(), PrefixLastIP(p))
}
// PrefixIPNet returns the net.IPNet representation of an netip.Prefix.
// The returned value is always non-nil.
// Any zone identifier is dropped in the conversion.
func PrefixIPNet(p netip.Prefix) *net.IPNet {
if !p.IsValid() {
return &net.IPNet{}
}
return &net.IPNet{
IP: p.Addr().AsSlice(),
Mask: net.CIDRMask(p.Bits(), p.Addr().BitLen()),
}
}
// AddrIPNet returns the net.IPNet representation of an netip.Addr
// with a mask corresponding to the addresses's bit length.
// The returned value is always non-nil.
// Any zone identifier is dropped in the conversion.
func AddrIPNet(addr netip.Addr) *net.IPNet {
if !addr.IsValid() {
return &net.IPNet{}
}
return &net.IPNet{
IP: addr.AsSlice(),
Mask: net.CIDRMask(addr.BitLen(), addr.BitLen()),
}
}
// PrefixLastIP returns the last IP in the prefix.
func PrefixLastIP(p netip.Prefix) netip.Addr {
if !p.IsValid() {
return netip.Addr{}
}
a16 := p.Addr().As16()
var off uint8
var bits uint8 = 128
if p.Addr().Is4() {
off = 12
bits = 32
}
for b := uint8(p.Bits()); b < bits; b++ {
byteNum, bitInByte := b/8, 7-(b%8)
a16[off+byteNum] |= 1 << uint(bitInByte)
}
if p.Addr().Is4() {
return netip.AddrFrom16(a16).Unmap()
} else {
return netip.AddrFrom16(a16) // doesn't unmap
}
}
// IPRange represents an inclusive range of IP addresses
// from the same address family.
//
// The From and To IPs are inclusive bounds, with both included in the
// range.
//
// To be valid, the From and To values must be non-zero, have matching
// address families (IPv4 vs IPv6), and From must be less than or equal to To.
// IPv6 zones are stripped out and ignored.
// An invalid range may be ignored.
type IPRange struct {
// from is the initial IP address in the range.
from netip.Addr
// to is the final IP address in the range.
to netip.Addr
}
// IPRangeFrom returns an IPRange from from to to.
// It does not allocate.
func IPRangeFrom(from, to netip.Addr) IPRange {
return IPRange{
from: from.WithZone(""),
to: to.WithZone(""),
}
}
// From returns the lower bound of r.
func (r IPRange) From() netip.Addr { return r.from }
// To returns the upper bound of r.
func (r IPRange) To() netip.Addr { return r.to }
// ParseIPRange parses a range out of two IPs separated by a hyphen.
//
// It returns an error if the range is not valid.
func ParseIPRange(s string) (IPRange, error) {
var r IPRange
h := strings.IndexByte(s, '-')
if h == -1 {
return r, fmt.Errorf("no hyphen in range %q", s)
}
from, to := s[:h], s[h+1:]
var err error
r.from, err = netip.ParseAddr(from)
if err != nil {
return r, fmt.Errorf("invalid From IP %q in range %q", from, s)
}
r.from = r.from.WithZone("")
r.to, err = netip.ParseAddr(to)
if err != nil {
return r, fmt.Errorf("invalid To IP %q in range %q", to, s)
}
r.to = r.to.WithZone("")
if !r.IsValid() {
return r, fmt.Errorf("range %v to %v not valid", r.from, r.to)
}
return r, nil
}
// MustParseIPRange calls ParseIPRange(s) and panics on error.
// It is intended for use in tests with hard-coded strings.
func MustParseIPRange(s string) IPRange {
r, err := ParseIPRange(s)
if err != nil {
panic(err)
}
return r
}
// String returns a string representation of the range.
//
// For a valid range, the form is "From-To" with a single hyphen
// separating the IPs, the same format recognized by
// ParseIPRange.
func (r IPRange) String() string {
if r.IsValid() {
return fmt.Sprintf("%s-%s", r.from, r.to)
}
if !r.from.IsValid() || !r.to.IsValid() {
return "zero IPRange"
}
return "invalid IPRange"
}
// AppendTo appends a text encoding of r,
// as generated by MarshalText,
// to b and returns the extended buffer.
func (r IPRange) AppendTo(b []byte) []byte {
if r.IsZero() {
return b
}
b = r.from.AppendTo(b)
b = append(b, '-')
b = r.to.AppendTo(b)
return b
}
// MarshalText implements the encoding.TextMarshaler interface,
// The encoding is the same as returned by String, with one exception:
// If ip is the zero value, the encoding is the empty string.
func (r IPRange) MarshalText() ([]byte, error) {
if r.IsZero() {
return []byte(""), nil
}
var max int
if r.from.Is4() {
max = len("255.255.255.255-255.255.255.255")
} else {
max = len("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff-ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")
}
b := make([]byte, 0, max)
return r.AppendTo(b), nil
}
// UnmarshalText implements the encoding.TextUnmarshaler interface.
// The IP range is expected in a form accepted by ParseIPRange.
// It returns an error if *r is not the IPRange zero value.
func (r *IPRange) UnmarshalText(text []byte) error {
if *r != (IPRange{}) {
return errors.New("refusing to Unmarshal into non-zero IPRange")
}
if len(text) == 0 {
return nil
}
var err error
*r, err = ParseIPRange(string(text))
return err
}
// IsZero reports whether r is the zero value of the IPRange type.
func (r IPRange) IsZero() bool {
return r == IPRange{}
}
// IsValid reports whether r.From() and r.To() are both non-zero and
// obey the documented requirements: address families match, and From
// is less than or equal to To.
func (r IPRange) IsValid() bool {
return r.from.IsValid() &&
r.from.BitLen() == r.to.BitLen() &&
r.from.Zone() == r.to.Zone() &&
!r.to.Less(r.from)
}
// Valid reports whether r.From() and r.To() are both non-zero and
// obey the documented requirements: address families match, and From
// is less than or equal to To.
//
// Deprecated: use the correctly named and identical IsValid method instead.
func (r IPRange) Valid() bool { return r.IsValid() }
// Contains reports whether the range r includes addr.
//
// An invalid range always reports false.
//
// If ip has an IPv6 zone, Contains returns false,
// because IPPrefixes strip zones.
func (r IPRange) Contains(addr netip.Addr) bool {
return r.IsValid() && addr.Zone() == "" && r.contains(addr)
}
// contains is like Contains, but without the validity check.
// addr must not have a zone.
func (r IPRange) contains(addr netip.Addr) bool {
return r.from.Compare(addr) <= 0 && r.to.Compare(addr) >= 0
}
// less reports whether r is "before" other. It is before if r.From()
// is before other.From(). If they're equal, then the larger range
// (higher To()) comes first.
func (r IPRange) less(other IPRange) bool {
if cmp := r.from.Compare(other.from); cmp != 0 {
return cmp < 0
}
return other.to.Less(r.to)
}
// entirelyBefore returns whether r lies entirely before other in IP
// space.
func (r IPRange) entirelyBefore(other IPRange) bool {
return r.to.Less(other.from)
}
func lessOrEq(ip, ip2 netip.Addr) bool { return ip.Compare(ip2) <= 0 }
// entirelyWithin returns whether r is entirely contained within
// other.
func (r IPRange) coveredBy(other IPRange) bool {
return lessOrEq(other.from, r.from) && lessOrEq(r.to, other.to)
}
// inMiddleOf returns whether r is inside other, but not touching the
// edges of other.
func (r IPRange) inMiddleOf(other IPRange) bool {
return other.from.Less(r.from) && r.to.Less(other.to)
}
// overlapsStartOf returns whether r entirely overlaps the start of
// other, but not all of other.
func (r IPRange) overlapsStartOf(other IPRange) bool {
return lessOrEq(r.from, other.from) && r.to.Less(other.to)
}
// overlapsEndOf returns whether r entirely overlaps the end of
// other, but not all of other.
func (r IPRange) overlapsEndOf(other IPRange) bool {
return other.from.Less(r.from) && lessOrEq(other.to, r.to)
}
// mergeIPRanges returns the minimum and sorted set of IP ranges that
// cover r.
func mergeIPRanges(rr []IPRange) (out []IPRange, valid bool) {
// Always return a copy of r, to avoid aliasing slice memory in
// the caller.
switch len(rr) {
case 0:
return nil, true
case 1:
return []IPRange{rr[0]}, true
}
sort.Slice(rr, func(i, j int) bool { return rr[i].less(rr[j]) })
out = make([]IPRange, 1, len(rr))
out[0] = rr[0]
for _, r := range rr[1:] {
prev := &out[len(out)-1]
switch {
case !r.IsValid():
// Invalid ranges make no sense to merge, refuse to
// perform.
return nil, false
case prev.to.Next() == r.from:
// prev and r touch, merge them.
//
// prev r
// f------tf-----t
prev.to = r.to
case prev.to.Less(r.from):
// No overlap and not adjacent (per previous case), no
// merging possible.
//
// prev r
// f------t f-----t
out = append(out, r)
case prev.to.Less(r.to):
// Partial overlap, update prev
//
// prev
// f------t
// f-----t
// r
prev.to = r.to
default:
// r entirely contained in prev, nothing to do.
//
// prev
// f--------t
// f-----t
// r
}
}
return out, true
}
// Overlaps reports whether p and o overlap at all.
//
// If p and o are of different address families or either are invalid,
// it reports false.
func (r IPRange) Overlaps(o IPRange) bool {
return r.IsValid() &&
o.IsValid() &&
r.from.Compare(o.to) <= 0 &&
o.from.Compare(r.to) <= 0
}
// prefixMaker returns a address-family-corrected IPPrefix from a and bits,
// where the input bits is always in the IPv6-mapped form for IPv4 addresses.
type prefixMaker func(a uint128, bits uint8) netip.Prefix
// Prefixes returns the set of IPPrefix entries that covers r.
//
// If either of r's bounds are invalid, in the wrong order, or if
// they're of different address families, then Prefixes returns nil.
//
// Prefixes necessarily allocates. See AppendPrefixes for a version that uses
// memory you provide.
func (r IPRange) Prefixes() []netip.Prefix {
return r.AppendPrefixes(nil)
}
// AppendPrefixes is an append version of IPRange.Prefixes. It appends
// the netip.Prefix entries that cover r to dst.
func (r IPRange) AppendPrefixes(dst []netip.Prefix) []netip.Prefix {
if !r.IsValid() {
return nil
}
return appendRangePrefixes(dst, r.prefixFrom128AndBits, u128From16(r.from.As16()), u128From16(r.to.As16()))
}
func (r IPRange) prefixFrom128AndBits(a uint128, bits uint8) netip.Prefix {
var ip netip.Addr
if r.from.Is4() {
bits -= 12 * 8
ip = a.IP4()
} else {
ip = a.IP6()
}
return netip.PrefixFrom(ip, int(bits))
}
// aZeroBSet is whether, after the common bits, a is all zero bits and
// b is all set (one) bits.
func comparePrefixes(a, b uint128) (common uint8, aZeroBSet bool) {
common = a.commonPrefixLen(b)
// See whether a and b, after their common shared bits, end
// in all zero bits or all one bits, respectively.
if common == 128 {
return common, true
}
m := mask6[common]
return common, (a.xor(a.and(m)).isZero() &&
b.or(m) == uint128{^uint64(0), ^uint64(0)})
}
// Prefix returns r as an IPPrefix, if it can be presented exactly as such.
// If r is not valid or is not exactly equal to one prefix, ok is false.
func (r IPRange) Prefix() (p netip.Prefix, ok bool) {
if !r.IsValid() {
return
}
from128 := u128From16(r.from.As16())
to128 := u128From16(r.to.As16())
if common, ok := comparePrefixes(from128, to128); ok {
return r.prefixFrom128AndBits(from128, common), true
}
return
}
func appendRangePrefixes(dst []netip.Prefix, makePrefix prefixMaker, a, b uint128) []netip.Prefix {
common, ok := comparePrefixes(a, b)
if ok {
// a to b represents a whole range, like 10.50.0.0/16.
// (a being 10.50.0.0 and b being 10.50.255.255)
return append(dst, makePrefix(a, common))
}
// Otherwise recursively do both halves.
dst = appendRangePrefixes(dst, makePrefix, a, a.bitsSetFrom(common+1))
dst = appendRangePrefixes(dst, makePrefix, b.bitsClearedFrom(common+1), b)
return dst
}
// ComparePrefix is a compare function (returning -1, 0 or 1)
// sorting prefixes first by address family (IPv4 before IPv6),
// then by prefix length (smaller prefixes first), then by
// address.
func ComparePrefix(a, b netip.Prefix) int {
aa, ba := a.Addr(), b.Addr()
if al, bl := aa.BitLen(), ba.BitLen(); al != bl {
if al < bl {
return -1
}
return 1
}
ab, bb := a.Bits(), b.Bits()
if ab != bb {
if ab < bb {
return -1
}
return 1
}
return aa.Compare(ba)
}
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