Function TestShouldSendToHost

wgengine/netstack/netstack_test.go:1214–1375

(t *testing.T)

}

func TestShouldSendToHost(t *testing.T) {
	var (
		selfIP4             = netip.MustParseAddr("100.64.1.2")
		selfIP6             = netip.MustParseAddr("fd7a:115c:a1e0::123")
		tailscaleServiceIP4 = netip.MustParseAddr("100.99.55.111")
		tailscaleServiceIP6 = netip.MustParseAddr("fd7a:115c:a1e0::abcd")
	)

	makeTestNetstack := func(tb testing.TB) *Impl {
		impl := makeNetstack(tb, func(impl *Impl) {
			impl.ProcessSubnets = false
			impl.ProcessLocalIPs = false
			impl.atomicIsLocalIPFunc.Store(func(addr netip.Addr) bool {
				return addr == selfIP4 || addr == selfIP6
			})
			impl.atomicIsVIPServiceIPFunc.Store(func(addr netip.Addr) bool {
				return addr == tailscaleServiceIP4 || addr == tailscaleServiceIP6
			})
		})

		prefs := ipn.NewPrefs()
		prefs.AdvertiseRoutes = []netip.Prefix{
			// $ tailscale debug via 7 10.1.1.0/24
			// fd7a:115c:a1e0:b1a:0:7:a01:100/120
			netip.MustParsePrefix("fd7a:115c:a1e0:b1a:0:7:a01:100/120"),
		}
		_, err := impl.lb.EditPrefs(&ipn.MaskedPrefs{
			Prefs:              *prefs,
			AdvertiseRoutesSet: true,
		})
		if err != nil {
			tb.Fatalf("EditPrefs: %v", err)
		}
		return impl
	}

	testCases := []struct {
		name     string
		src, dst netip.AddrPort
		want     bool
	}{
		// Reply from service IP to localhost should be sent to host,
		// not over WireGuard.
		{
			name: "from_service_ip_to_localhost",
			src:  netip.AddrPortFrom(serviceIP, 53),
			dst:  netip.MustParseAddrPort("127.0.0.1:9999"),
			want: true,
		},
		{
			name: "from_service_ip_to_localhost_v6",
			src:  netip.AddrPortFrom(serviceIPv6, 53),
			dst:  netip.MustParseAddrPort("[::1]:9999"),
			want: true,
		},
		// A reply from the local IP to a remote host isn't sent to the
		// host, but rather over WireGuard.
		{