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			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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| 
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| package tun
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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| 	checkAlignment(t, "NativeTun.rate", unsafe.Offsetof(tun.rate))
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| }
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