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// 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
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)
}