// Copyright 2019 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.

//go:build aix || darwin || freebsd || linux || netbsd || openbsd || solaris || zos

// +build aix darwin freebsd linux netbsd openbsd solaris zos

package unix

import (

	"runtime"

)

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

func cmsgAlignOf(salen int) int {

	salign := SizeofPtr

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

	// sockcmsg_dragonfly.go

	switch runtime.GOOS {

	case "aix":

		// There is no alignment on AIX.

		salign = 1

	case "darwin", "ios", "illumos", "solaris":

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

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

		// subsystem.

		if SizeofPtr == 8 {

			salign = 4

		}

	case "netbsd", "openbsd":

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

		if runtime.GOARCH == "arm" {

			salign = 8

		}

		// NetBSD aarch64 requires 128-bit alignment.

		if runtime.GOOS == "netbsd" && runtime.GOARCH == "arm64" {

			salign = 16

		}

	case "zos":

		// z/OS socket macros use [32-bit] sizeof(int) alignment,

		// not pointer width.

		salign = SizeofInt

	}

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

}