TUN-4597: Add a QUIC server skeleton

- Added a QUIC server to accept streams
- Unit test for this server also tests ALPN
- Temporary echo capability for HTTP ConnectionType

vendor/golang.org/x/sys/windows/security_windows.go

@@ -908,6 +908,19 @@ type SECURITY_DESCRIPTOR struct {
 	dacl     *ACL
 }
 
+type SECURITY_QUALITY_OF_SERVICE struct {
+	Length              uint32
+	ImpersonationLevel  uint32
+	ContextTrackingMode byte
+	EffectiveOnly       byte
+}
+
+// Constants for the ContextTrackingMode field of SECURITY_QUALITY_OF_SERVICE.
+const (
+	SECURITY_STATIC_TRACKING  = 0
+	SECURITY_DYNAMIC_TRACKING = 1
+)
+
 type SecurityAttributes struct {
 	Length             uint32
 	SecurityDescriptor *SECURITY_DESCRIPTOR
@@ -1321,7 +1334,11 @@ func (absoluteSD *SECURITY_DESCRIPTOR) ToSelfRelative() (selfRelativeSD *SECURIT
 }
 
 func (selfRelativeSD *SECURITY_DESCRIPTOR) copySelfRelativeSecurityDescriptor() *SECURITY_DESCRIPTOR {
-	sdLen := (int)(selfRelativeSD.Length())
+	sdLen := int(selfRelativeSD.Length())
+	const min = int(unsafe.Sizeof(SECURITY_DESCRIPTOR{}))
+	if sdLen < min {
+		sdLen = min
+	}
 
 	var src []byte
 	h := (*unsafeheader.Slice)(unsafe.Pointer(&src))
@@ -1329,7 +1346,15 @@ func (selfRelativeSD *SECURITY_DESCRIPTOR) copySelfRelativeSecurityDescriptor()
 	h.Len = sdLen
 	h.Cap = sdLen
 
-	dst := make([]byte, sdLen)
+	const psize = int(unsafe.Sizeof(uintptr(0)))
+
+	var dst []byte
+	h = (*unsafeheader.Slice)(unsafe.Pointer(&dst))
+	alloc := make([]uintptr, (sdLen+psize-1)/psize)
+	h.Data = (*unsafeheader.Slice)(unsafe.Pointer(&alloc)).Data
+	h.Len = sdLen
+	h.Cap = sdLen
+
 	copy(dst, src)
 	return (*SECURITY_DESCRIPTOR)(unsafe.Pointer(&dst[0]))
 }