/* SPDX-License-Identifier: MIT * * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved. */ package device import ( "reflect" "testing" "unsafe" ) func checkAlignment(t *testing.T, name string, offset uintptr) { t.Helper() if offset%8 != 0 { t.Errorf("offset of %q within struct is %d bytes, which does not align to 64-bit word boundaries (missing %d bytes). Atomic operations will crash on 32-bit systems.", name, offset, 8-(offset%8)) } } // TestPeerAlignment checks that atomically-accessed fields are // aligned to 64-bit boundaries, as required by the atomic package. // // Unfortunately, violating this rule on 32-bit platforms results in a // hard segfault at runtime. func TestPeerAlignment(t *testing.T) { var p Peer typ := reflect.TypeOf(&p).Elem() t.Logf("Peer type size: %d, with fields:", typ.Size()) for i := 0; i < typ.NumField(); i++ { field := typ.Field(i) t.Logf("\t%30s\toffset=%3v\t(type size=%3d, align=%d)", field.Name, field.Offset, field.Type.Size(), field.Type.Align(), ) } checkAlignment(t, "Peer.stats", unsafe.Offsetof(p.stats)) checkAlignment(t, "Peer.isRunning", unsafe.Offsetof(p.isRunning)) } // TestDeviceAlignment checks that atomically-accessed fields are // aligned to 64-bit boundaries, as required by the atomic package. // // Unfortunately, violating this rule on 32-bit platforms results in a // hard segfault at runtime. func TestDeviceAlignment(t *testing.T) { var d Device typ := reflect.TypeOf(&d).Elem() t.Logf("Device type size: %d, with fields:", typ.Size()) for i := 0; i < typ.NumField(); i++ { field := typ.Field(i) t.Logf("\t%30s\toffset=%3v\t(type size=%3d, align=%d)", field.Name, field.Offset, field.Type.Size(), field.Type.Align(), ) } checkAlignment(t, "Device.rate.underLoadUntil", unsafe.Offsetof(d.rate)+unsafe.Offsetof(d.rate.underLoadUntil)) }