1 // Copyright 2019 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 aix darwin freebsd linux netbsd openbsd solaris

     6 

     7 package unix

     8 

     9 import (

    10 	"runtime"

    11 )

    12 

    13 // Round the length of a raw sockaddr up to align it properly.

    14 func cmsgAlignOf(salen int) int {

    15 	salign := SizeofPtr

    16 

    17 	// dragonfly needs to check ABI version at runtime, see cmsgAlignOf in

    18 	// sockcmsg_dragonfly.go

    19 	switch runtime.GOOS {

    20 	case "aix":

    21 		// There is no alignment on AIX.

    22 		salign = 1

    23 	case "darwin", "illumos", "solaris":

    24 		// NOTE: It seems like 64-bit Darwin, Illumos and Solaris

    25 		// kernels still require 32-bit aligned access to network

    26 		// subsystem.

    27 		if SizeofPtr == 8 {

    28 			salign = 4

    29 		}

    30 	case "netbsd", "openbsd":

    31 		// NetBSD and OpenBSD armv7 require 64-bit alignment.

    32 		if runtime.GOARCH == "arm" {

    33 			salign = 8

    34 		}

    35 	}

    36 

    37 	return (salen + salign - 1) & ^(salign - 1)

    38 }