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 //go:build aix || darwin || freebsd || linux || netbsd || openbsd || solaris || zos 6 // +build aix darwin freebsd linux netbsd openbsd solaris zos 7 8 package unix 9 10 import ( 11 "runtime" 12 ) 13 14 // Round the length of a raw sockaddr up to align it properly. 15 func cmsgAlignOf(salen int) int { 16 salign := SizeofPtr 17 18 // dragonfly needs to check ABI version at runtime, see cmsgAlignOf in 19 // sockcmsg_dragonfly.go 20 switch runtime.GOOS { 21 case "aix": 22 // There is no alignment on AIX. 23 salign = 1 24 case "darwin", "ios", "illumos", "solaris": 25 // NOTE: It seems like 64-bit Darwin, Illumos and Solaris 26 // kernels still require 32-bit aligned access to network 27 // subsystem. 28 if SizeofPtr == 8 { 29 salign = 4 30 } 31 case "netbsd", "openbsd": 32 // NetBSD and OpenBSD armv7 require 64-bit alignment. 33 if runtime.GOARCH == "arm" { 34 salign = 8 35 } 36 // NetBSD aarch64 requires 128-bit alignment. 37 if runtime.GOOS == "netbsd" && runtime.GOARCH == "arm64" { 38 salign = 16 39 } 40 case "zos": 41 // z/OS socket macros use [32-bit] sizeof(int) alignment, 42 // not pointer width. 43 salign = SizeofInt 44 } 45 46 return (salen + salign - 1) & ^(salign - 1) 47 } 48