github.com/Andyfoo/golang/x/net@v0.0.0-20190901054642-57c1bf301704/route/sys.go (about)

     1  // Copyright 2016 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build darwin dragonfly freebsd netbsd openbsd
     6  
     7  package route
     8  
     9  import "unsafe"
    10  
    11  var (
    12  	nativeEndian binaryByteOrder
    13  	kernelAlign  int
    14  	wireFormats  map[int]*wireFormat
    15  )
    16  
    17  func init() {
    18  	i := uint32(1)
    19  	b := (*[4]byte)(unsafe.Pointer(&i))
    20  	if b[0] == 1 {
    21  		nativeEndian = littleEndian
    22  	} else {
    23  		nativeEndian = bigEndian
    24  	}
    25  	kernelAlign, wireFormats = probeRoutingStack()
    26  }
    27  
    28  func roundup(l int) int {
    29  	if l == 0 {
    30  		return kernelAlign
    31  	}
    32  	return (l + kernelAlign - 1) &^ (kernelAlign - 1)
    33  }
    34  
    35  type wireFormat struct {
    36  	extOff  int // offset of header extension
    37  	bodyOff int // offset of message body
    38  	parse   func(RIBType, []byte) (Message, error)
    39  }