multi: only allow specifying towers to TowerClient through RPC

With the introduction of the WatchtowerClient RPC subserver, the lnd
configuration flag to specify private watchtowers for the client is no
longer needed and can lead to confusion upon users. Therefore, we remove
the flag completely, and only rely on the watchtower client being active
through a new --wtclient.active flag.

watchtower/wtclient/client_test.go

@@ -26,7 +26,11 @@ import (
 	"github.com/lightningnetwork/lnd/watchtower/wtserver"
 )
 
-const csvDelay uint32 = 144
+const (
+	csvDelay uint32 = 144
+
+	towerAddrStr = "18.28.243.2:9911"
+)
 
 var (
 	revPrivBytes = []byte{
@@ -387,7 +391,6 @@ type harnessCfg struct {
 }
 
 func newHarness(t *testing.T, cfg harnessCfg) *testHarness {
-	towerAddrStr := "18.28.243.2:9911"
 	towerTCPAddr, err := net.ResolveTCPAddr("tcp", towerAddrStr)
 	if err != nil {
 		t.Fatalf("Unable to resolve tower TCP addr: %v", err)
@@ -412,6 +415,7 @@ func newHarness(t *testing.T, cfg harnessCfg) *testHarness {
 		DB:           serverDB,
 		ReadTimeout:  timeout,
 		WriteTimeout: timeout,
+		NodePrivKey:  privKey,
 		NewAddress: func() (btcutil.Address, error) {
 			return addr, nil
 		},
@@ -435,7 +439,6 @@ func newHarness(t *testing.T, cfg harnessCfg) *testHarness {
 		DB:            clientDB,
 		AuthDial:      mockNet.AuthDial,
 		SecretKeyRing: wtmock.NewSecretKeyRing(),
-		PrivateTower:  towerAddr,
 		Policy:        cfg.policy,
 		NewAddress: func() ([]byte, error) {
 			return addrScript, nil
@@ -458,6 +461,10 @@ func newHarness(t *testing.T, cfg harnessCfg) *testHarness {
 		server.Stop()
 		t.Fatalf("Unable to start wtclient: %v", err)
 	}
+	if err := client.AddTower(towerAddr); err != nil {
+		server.Stop()
+		t.Fatalf("Unable to add tower to wtclient: %v", err)
+	}
 
 	h := &testHarness{
 		t:         t,
@@ -505,7 +512,15 @@ func (h *testHarness) startServer() {
 func (h *testHarness) startClient() {
 	h.t.Helper()
 
-	var err error
+	towerTCPAddr, err := net.ResolveTCPAddr("tcp", towerAddrStr)
+	if err != nil {
+		h.t.Fatalf("Unable to resolve tower TCP addr: %v", err)
+	}
+	towerAddr := &lnwire.NetAddress{
+		IdentityKey: h.serverCfg.NodePrivKey.PubKey(),
+		Address:     towerTCPAddr,
+	}
+
 	h.client, err = wtclient.New(h.clientCfg)
 	if err != nil {
 		h.t.Fatalf("unable to create wtclient: %v", err)
@@ -513,6 +528,9 @@ func (h *testHarness) startClient() {
 	if err := h.client.Start(); err != nil {
 		h.t.Fatalf("unable to start wtclient: %v", err)
 	}
+	if err := h.client.AddTower(towerAddr); err != nil {
+		h.t.Fatalf("unable to add tower to wtclient: %v", err)
+	}
 }
 
 // chanIDFromInt creates a unique channel id given a unique integral id.