68 lines
1.9 KiB
Go
68 lines
1.9 KiB
Go
/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
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*/
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package tun
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import (
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"reflect"
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"testing"
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"unsafe"
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)
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func checkAlignment(t *testing.T, name string, offset uintptr) {
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t.Helper()
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if offset%8 != 0 {
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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))
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}
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}
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// TestRateJugglerAlignment checks that atomically-accessed fields are
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// aligned to 64-bit boundaries, as required by the atomic package.
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//
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// Unfortunately, violating this rule on 32-bit platforms results in a
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// hard segfault at runtime.
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func TestRateJugglerAlignment(t *testing.T) {
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var r rateJuggler
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typ := reflect.TypeOf(&r).Elem()
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t.Logf("Peer type size: %d, with fields:", typ.Size())
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for i := 0; i < typ.NumField(); i++ {
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field := typ.Field(i)
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t.Logf("\t%30s\toffset=%3v\t(type size=%3d, align=%d)",
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field.Name,
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field.Offset,
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field.Type.Size(),
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field.Type.Align(),
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)
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}
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checkAlignment(t, "rateJuggler.current", unsafe.Offsetof(r.current))
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checkAlignment(t, "rateJuggler.nextByteCount", unsafe.Offsetof(r.nextByteCount))
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checkAlignment(t, "rateJuggler.nextStartTime", unsafe.Offsetof(r.nextStartTime))
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}
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// TestNativeTunAlignment checks that atomically-accessed fields are
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// aligned to 64-bit boundaries, as required by the atomic package.
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//
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// Unfortunately, violating this rule on 32-bit platforms results in a
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// hard segfault at runtime.
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func TestNativeTunAlignment(t *testing.T) {
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var tun NativeTun
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typ := reflect.TypeOf(&tun).Elem()
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t.Logf("Peer type size: %d, with fields:", typ.Size())
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for i := 0; i < typ.NumField(); i++ {
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field := typ.Field(i)
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t.Logf("\t%30s\toffset=%3v\t(type size=%3d, align=%d)",
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field.Name,
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field.Offset,
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field.Type.Size(),
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field.Type.Align(),
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)
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}
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checkAlignment(t, "NativeTun.rate", unsafe.Offsetof(tun.rate))
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}
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