Function TestInjectInboundLeak

wgengine/netstack/netstack_test.go:43–98

TestInjectInboundLeak tests that injectInbound doesn't leak memory. See https://github.com/tailscale/tailscale/issues/3762

(t *testing.T)

// TestInjectInboundLeak tests that injectInbound doesn't leak memory.
// See https://github.com/tailscale/tailscale/issues/3762
func TestInjectInboundLeak(t *testing.T) {
	tunDev := tstun.NewFake()
	dialer := new(tsdial.Dialer)
	logf := func(format string, args ...any) {
		if !t.Failed() {
			t.Logf(format, args...)
		}
	}
	sys := tsd.NewSystem()
	eng, err := wgengine.NewUserspaceEngine(logf, wgengine.Config{
		Tun:           tunDev,
		Dialer:        dialer,
		SetSubsystem:  sys.Set,
		HealthTracker: sys.HealthTracker.Get(),
		Metrics:       sys.UserMetricsRegistry(),
		EventBus:      sys.Bus.Get(),
	})
	if err != nil {
		t.Fatal(err)
	}
	defer eng.Close()
	sys.Set(eng)
	sys.Set(new(mem.Store))

	tunWrap := sys.Tun.Get()
	lb, err := ipnlocal.NewLocalBackend(logf, logid.PublicID{}, sys, 0)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(lb.Shutdown)

	ns, err := Create(logf, tunWrap, eng, sys.MagicSock.Get(), dialer, sys.DNSManager.Get(), sys.ProxyMapper())
	if err != nil {
		t.Fatal(err)
	}
	defer ns.Close()
	ns.ProcessLocalIPs = true
	if err := ns.Start(lb); err != nil {
		t.Fatalf("Start: %v", err)
	}
	ns.atomicIsLocalIPFunc.Store(func(netip.Addr) bool { return true })

	pkt := &packet.Parsed{}
	const N = 10_000
	ms0 := getMemStats()
	for range N {
		outcome, _ := ns.injectInbound(pkt, tunWrap, nil)
		if outcome != filter.DropSilently {
			t.Fatalf("got outcome %v; want DropSilently", outcome)
		}
	}
	ms1 := getMemStats()
	if grew := int64(ms1.HeapObjects) - int64(ms0.HeapObjects); grew >= N {
		t.Fatalf("grew by %v (which is too much and >= the %v packets we sent)", grew, N)
	}
}

func getMemStats() (ms runtime.MemStats) {