kernelAlign  int
	rtmVersion   byte
	wireFormats  map[int]*wireFormat
)

func init() {
	i := uint32(1)
	b := (*[4]byte)(unsafe.Pointer(&i))
	if b[0] == 1 {
		nativeEndian = littleEndian
	} else {
		nativeEndian = bigEndian
	}
	// might get overridden in probeRoutingStack
	rtmVersion = syscall.RTM_VERSION
	kernelAlign, wireFormats = probeRoutingStack()
}

func roundup(l int) int {

//go:build darwin || dragonfly || freebsd || netbsd

package route

import (
	"runtime"
	"syscall"
)

func (m *RouteMessage) marshal() ([]byte, error) {
	w, ok := wireFormats[m.Type]
	if !ok {
		return nil, errUnsupportedMessage
	}
	l := w.bodyOff + addrsSpace(m.Addrs)
	if runtime.GOOS == "darwin" || runtime.GOOS == "ios" {
		// Fix stray pointer writes on macOS.

		if l == 0 {
			return nil, errInvalidMessage
		}
		if len(b) < l {
			return nil, errMessageTooShort
		}
		if b[2] != rtmVersion {
			b = b[l:]
			continue
		}
		if w, ok := wireFormats[int(b[3])]; !ok {
			nskips++
		} else {
			m, err := w.parse(typ, b[:l])
			if err != nil {
				return nil, err
			}
			if m == nil {
				nskips++
			} else {
				msgs = append(msgs, m)
			}
		}

		},
	}
}

func probeRoutingStack() (int, map[int]*wireFormat) {
	var p uintptr
	rtm := &wireFormat{extOff: 40, bodyOff: sizeofRtMsghdrDragonFlyBSD4}
	rtm.parse = rtm.parseRouteMessage
	ifm := &wireFormat{extOff: 16, bodyOff: sizeofIfMsghdrDragonFlyBSD4}
	ifm.parse = ifm.parseInterfaceMessage
	ifam := &wireFormat{extOff: sizeofIfaMsghdrDragonFlyBSD4, bodyOff: sizeofIfaMsghdrDragonFlyBSD4}

}

func probeRoutingStack() (int, map[int]*wireFormat) {
	rtm := &wireFormat{extOff: 40, bodyOff: sizeofRtMsghdrNetBSD7}
	rtm.parse = rtm.parseRouteMessage
	ifm := &wireFormat{extOff: 16, bodyOff: sizeofIfMsghdrNetBSD7}
	ifm.parse = ifm.parseInterfaceMessage
	ifam := &wireFormat{extOff: sizeofIfaMsghdrNetBSD7, bodyOff: sizeofIfaMsghdrNetBSD7}
	ifam.parse = ifam.parseInterfaceAddrMessage

	} else {
		rtm = &wireFormat{extOff: sizeofRtMsghdrFreeBSD10 - sizeofRtMetricsFreeBSD10, bodyOff: sizeofRtMsghdrFreeBSD10}
		ifm = &wireFormat{extOff: 16}
		ifam = &wireFormat{extOff: sizeofIfaMsghdrFreeBSD10, bodyOff: sizeofIfaMsghdrFreeBSD10}
		ifmam = &wireFormat{extOff: sizeofIfmaMsghdrFreeBSD10, bodyOff: sizeofIfmaMsghdrFreeBSD10}

	}
}

func probeRoutingStack() (int, map[int]*wireFormat) {
	rtm := &wireFormat{extOff: 36, bodyOff: sizeofRtMsghdrDarwin15}
	rtm.parse = rtm.parseRouteMessage
	rtm2 := &wireFormat{extOff: 36, bodyOff: sizeofRtMsghdr2Darwin15}
	rtm2.parse = rtm2.parseRouteMessage
	ifm := &wireFormat{extOff: 16, bodyOff: sizeofIfMsghdrDarwin15}
	ifm.parse = ifm.parseInterfaceMessage
	ifm2 := &wireFormat{extOff: 32, bodyOff: sizeofIfMsghdr2Darwin15}

		},
	}
}

func probeRoutingStack() (int, map[int]*wireFormat) {
	var p uintptr
	rtm := &wireFormat{extOff: -1, bodyOff: -1}
	rtm.parse = rtm.parseRouteMessage
	ifm := &wireFormat{extOff: -1, bodyOff: -1}
	ifm.parse = ifm.parseInterfaceMessage
	ifam := &wireFormat{extOff: -1, bodyOff: -1}
	ifam.parse = ifam.parseInterfaceAddrMessage
	ifanm := &wireFormat{extOff: -1, bodyOff: -1}
	ifanm.parse = ifanm.parseInterfaceAnnounceMessage

// Copyright 2016 The Go 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 route

import "syscall"

func (*wireFormat) parseInterfaceMessage(_ RIBType, b []byte) (Message, error) {
	if len(b) < 32 {
		return nil, errMessageTooShort
	}
	l := int(nativeEndian.Uint16(b[:2]))
	if len(b) < l {
		return nil, errInvalidMessage
	}

// Copyright 2016 The Go 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 route

import "syscall"

func (w *wireFormat) parseInterfaceMessage(typ RIBType, b []byte) (Message, error) {
	var extOff, bodyOff int
	if typ == syscall.NET_RT_IFLISTL {
		if len(b) < 20 {
			return nil, errMessageTooShort
		}
		extOff = int(nativeEndian.Uint16(b[18:20]))