b := make([]byte, l)
	nativeEndian.PutUint16(b[:2], uint16(l))
	if m.Version == 0 {
		b[2] = syscall.RTM_VERSION
	} else {
		b[2] = byte(m.Version)
	}
	b[3] = byte(m.Type)
	nativeEndian.PutUint16(b[4:6], uint16(sizeofRtMsghdr))
	nativeEndian.PutUint32(b[16:20], uint32(m.Flags))
	nativeEndian.PutUint16(b[6:8], uint16(m.Index))
	nativeEndian.PutUint32(b[24:28], uint32(m.ID))

// Issue 1011.  Removing either #1 or #3 avoided the crash at #2.

package main

import (
	"io"
	"strings"
)

func readU16BE(b []byte) uint16 {
	b[0] = 0
	b[1] = 1
	return uint16(b[0])<<8 + uint16(b[1]) // #1
	n := uint16(b[0])<<8 + uint16(b[1])
	return n
}

func readStr(r io.Reader, b []byte) string {
	n := readU16BE(b)
	if int(n) > len(b) {
		return "err: n>b"
	}

	Lastchange Timespec
}

type IfaMsghdr struct {
	Msglen    uint16
	Version   uint8
	Type      uint8
	Addrs     int32
	Flags     int32
	Metric    int32
	Index     uint16
	Pad_cgo_0 [6]byte
}

type IfAnnounceMsghdr struct {
	Msglen  uint16
	Version uint8
	Type    uint8
	Index   uint16
	Name    [16]int8
	What    uint16
}

type RtMsghdr struct {
	Msglen    uint16

	Lastchange Timespec
}

type IfaMsghdr struct {
	Msglen    uint16
	Version   uint8
	Type      uint8
	Addrs     int32
	Flags     int32
	Metric    int32
	Index     uint16
	Pad_cgo_0 [6]byte
}

type IfAnnounceMsghdr struct {
	Msglen  uint16
	Version uint8
	Type    uint8
	Index   uint16
	Name    [16]int8
	What    uint16
}

type RtMsghdr struct {
	Msglen    uint16

	Lastchange Timespec
}

type IfaMsghdr struct {
	Msglen    uint16
	Version   uint8
	Type      uint8
	Addrs     int32
	Flags     int32
	Metric    int32
	Index     uint16
	Pad_cgo_0 [6]byte
}

type IfAnnounceMsghdr struct {
	Msglen  uint16
	Version uint8
	Type    uint8
	Index   uint16
	Name    [16]int8
	What    uint16
}

type RtMsghdr struct {
	Msglen    uint16

	if len(b) < 26 {
		return nil, errMessageTooShort
	}
	l := int(nativeEndian.Uint16(b[:2]))
	if len(b) < l {
		return nil, errInvalidMessage
	}
	m := &InterfaceAnnounceMessage{
		Version: int(b[2]),
		Type:    int(b[3]),
		Index:   int(nativeEndian.Uint16(b[6:8])),
		What:    int(nativeEndian.Uint16(b[8:10])),
		raw:     b[:l],
	}
	for i := 0; i < 16; i++ {
		if b[10+i] != 0 {
			continue
		}

)

const (
	PIDFD_NONBLOCK = 0x800
)

type SysvIpcPerm struct {
	Key  int32
	Uid  uint32
	Gid  uint32
	Cuid uint32
	Cgid uint32
	Mode uint16
	_    [2]uint8
	Seq  uint16
	_    uint16
	_    uint32
	_    uint32
}
type SysvShmDesc struct {
	Perm       SysvIpcPerm
	Segsz      uint32
	Atime      uint32
	Atime_high uint32
	Dtime      uint32

type dhKEM struct {
	dh  ecdh.Curve
	kdf hkdfKDF

	suiteID []byte
	nSecret uint16
}

var SupportedKEMs = map[uint16]struct {
	curve   ecdh.Curve
	hash    crypto.Hash
	nSecret uint16
}{
	// RFC 9180 Section 7.1
	0x0020: {ecdh.X25519(), crypto.SHA256, 32},
}

func newDHKem(kemID uint16) (*dhKEM, error) {
	suite, ok := SupportedKEMs[kemID]
	if !ok {

type littleEndian struct{}

func (littleEndian) Uint16(b []byte) uint16 {
	_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
	return uint16(b[0]) | uint16(b[1])<<8
}

func (littleEndian) PutUint16(b []byte, v uint16) {
	_ = b[1] // early bounds check to guarantee safety of writes below
	b[0] = byte(v)
	b[1] = byte(v >> 8)
}

func (littleEndian) AppendUint16(b []byte, v uint16) []byte {
	return append(b,
		byte(v),

type Stat_t struct {
	Dev     uint64
	_       uint16
	_       uint32
	Mode    uint32
	Nlink   uint32
	Uid     uint32
	Gid     uint32
	Rdev    uint64
	_       uint16
	Size    int64
	Blksize int32
	Blocks  int64
	Atim    Timespec
	Mtim    Timespec
	Ctim    Timespec
	Ino     uint64
}

type Dirent struct {
	Ino    uint64
	Off    int64
	Reclen uint16
	Type   uint8
	Name   [256]int8