staticaddr: multi-address loop-in

hieblmi · hieblmi · commit 0310a7e16647 · 2025-10-29T10:06:38.000+01:00
diff --git a/loopd/daemon.go b/loopd/daemon.go
@@ -677,6 +677,7 @@ func (d *Daemon) initialize(withMacaroonService bool) error {
 		LndClient:                            d.lnd.Client,
 		InvoicesClient:                       d.lnd.Invoices,
 		NodePubkey:                           d.lnd.NodePubkey,
+		AddressManager:                       staticAddressManager,
 		DepositManager:                       depositManager,
 		Store:                                staticAddressLoopInStore,
 		WalletKit:                            d.lnd.WalletKit,
diff --git a/loopdb/sqlc/migrations/000022_static_change_address.down.sql b/loopdb/sqlc/migrations/000022_static_change_address.down.sql
@@ -0,0 +1 @@
+ALTER TABLE static_address_swaps DROP COLUMN change_address;
diff --git a/loopdb/sqlc/migrations/000022_static_change_address.up.sql b/loopdb/sqlc/migrations/000022_static_change_address.up.sql
@@ -0,0 +1,3 @@
+-- change_address stores the change output address for the HTLC transaction of a
+-- static address loop-in swap.
+ALTER TABLE static_address_swaps ADD change_address TEXT NOT NULL DEFAULT '';
diff --git a/loopdb/sqlc/models.go b/loopdb/sqlc/models.go
diff --git a/loopdb/sqlc/queries/static_address_loopin.sql b/loopdb/sqlc/queries/static_address_loopin.sql
@@ -7,6 +7,7 @@ INSERT INTO static_address_swaps (
     quoted_swap_fee_satoshis,
     deposit_outpoints,
     selected_amount,
+    change_address,
     htlc_tx_fee_rate_sat_kw,
     htlc_timeout_sweep_tx_id,
     htlc_timeout_sweep_address,
@@ -22,7 +23,8 @@ INSERT INTO static_address_swaps (
     $8,
     $9,
     $10,
-    $11
+    $11,
+    $12
 );
 
 -- name: UpdateStaticAddressLoopIn :exec
diff --git a/loopdb/sqlc/static_address_loopin.sql.go b/loopdb/sqlc/static_address_loopin.sql.go
diff --git a/staticaddr/deposit/manager_test.go b/staticaddr/deposit/manager_test.go
@@ -312,6 +312,9 @@ func newManagerTestContext(t *testing.T) *ManagerTestContext {
 		},
 	}
 	require.NoError(t, err)
+
+	_, clientPub := test.CreateKey(1)
+	_, serverPub := test.CreateKey(2)
 	storedDeposits := []*Deposit{
 		{
 			ID:                   ID,
@@ -324,6 +327,9 @@ func newManagerTestContext(t *testing.T) *ManagerTestContext {
 			AddressParams: &address.Parameters{
 				ProtocolVersion: version.ProtocolVersion_V0,
 				Expiry:          100,
+				ClientPubkey:    clientPub,
+				ServerPubkey:    serverPub,
+				PkScript:        utxo.PkScript,
 			},
 		},
 	}
diff --git a/staticaddr/loopin/actions.go b/staticaddr/loopin/actions.go
@@ -16,6 +16,7 @@ import (
 	"github.com/lightninglabs/lndclient"
 	"github.com/lightninglabs/loop"
 	"github.com/lightninglabs/loop/fsm"
+	"github.com/lightninglabs/loop/staticaddr/address"
 	"github.com/lightninglabs/loop/staticaddr/deposit"
 	"github.com/lightninglabs/loop/staticaddr/version"
 	"github.com/lightninglabs/loop/swap"
@@ -63,15 +64,53 @@ func (f *FSM) InitHtlcAction(ctx context.Context,
 
 	// Calculate the swap invoice amount. The server needs to pay us the
 	// swap amount minus the fees that the server charges for the swap. The
-	// swap amount is either the total value of the selected deposits, or
-	// the selected amount if a specific amount was requested.
-	swapAmount := f.loopIn.TotalDepositAmount()
-	var hasChange bool
+	// swap amount is either the total value of the selected deposits or the
+	// selected amount if a specific amount was requested. If the selection
+	// results in change, we create a new static address for it.
+	var (
+		swapAmount       = f.loopIn.TotalDepositAmount()
+		hasChange        bool
+		changeAddrParams *address.Parameters
+	)
 	if f.loopIn.SelectedAmount > 0 {
 		swapAmount = f.loopIn.SelectedAmount
 		remainingAmount := f.loopIn.TotalDepositAmount() - swapAmount
 		hasChange = remainingAmount > 0 && remainingAmount <
 			f.loopIn.TotalDepositAmount()
+
+		if hasChange {
+			changeAddrParams, err = f.cfg.AddressManager.NewAddress(
+				ctx,
+			)
+			if err != nil {
+				err = fmt.Errorf("unable to create change "+
+					"address: %w", err)
+
+				return f.HandleError(err)
+			}
+
+			taprootAddress, err := changeAddrParams.TaprootAddress(
+				f.cfg.ChainParams,
+			)
+			if err != nil {
+				err = fmt.Errorf("unable to create taproot "+
+					"address: %w", err)
+
+				return f.HandleError(err)
+			}
+
+			changeAddress, err := btcutil.DecodeAddress(
+				taprootAddress, f.cfg.ChainParams,
+			)
+			if err != nil {
+				err = fmt.Errorf("unable to decode change "+
+					"address: %w", err)
+
+				return f.HandleError(err)
+			}
+
+			f.loopIn.ChangeAddress = changeAddress
+		}
 	}
 	swapInvoiceAmt := swapAmount - f.loopIn.QuotedSwapFee
 
@@ -124,6 +163,7 @@ func (f *FSM) InitHtlcAction(ctx context.Context,
 		SwapHash:              f.loopIn.SwapHash[:],
 		DepositOutpoints:      f.loopIn.DepositOutpoints,
 		Amount:                uint64(f.loopIn.SelectedAmount),
+		ChangeAddress:         f.loopIn.ChangeAddress.String(),
 		HtlcClientPubKey:      f.loopIn.ClientPubkey.SerializeCompressed(),
 		SwapInvoice:           f.loopIn.SwapInvoice,
 		ProtocolVersion:       version.CurrentRPCProtocolVersion(),
diff --git a/staticaddr/loopin/interface.go b/staticaddr/loopin/interface.go
@@ -6,6 +6,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/lightninglabs/loop"
 	"github.com/lightninglabs/loop/fsm"
+	"github.com/lightninglabs/loop/staticaddr/address"
 	"github.com/lightninglabs/loop/staticaddr/deposit"
 	"github.com/lightninglabs/loop/swapserverrpc"
 	"github.com/lightningnetwork/lnd/lntypes"
@@ -32,6 +33,9 @@ type (
 
 // AddressManager handles fetching of address parameters.
 type AddressManager interface {
+	// NewAddress returns a new static address.
+	NewAddress(ctx context.Context) (*address.Parameters, error)
+
 	// IsOurPkScript returns true if the given pkScript is our static
 	// address script.
 	IsOurPkScript(pkScript []byte) bool
diff --git a/staticaddr/loopin/selected_amount_migration_test.go b/staticaddr/loopin/selected_amount_migration_test.go
@@ -10,6 +10,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightninglabs/loop/loopdb"
+	"github.com/lightninglabs/loop/staticaddr/address"
 	"github.com/lightninglabs/loop/staticaddr/deposit"
 	"github.com/lightninglabs/loop/test"
 	"github.com/lightningnetwork/lnd/clock"
@@ -26,6 +27,7 @@ func TestMigrateSelectedSwapAmount(t *testing.T) {
 	defer testDb.Close()
 
 	db := loopdb.NewStoreMock(t)
+	addressStore := address.NewSqlStore(testDb.BaseDB)
 	depositStore := deposit.NewSqlStore(testDb.BaseDB)
 	swapStore := NewSqlStore(
 		loopdb.NewTypedStore[Querier](testDb), testClock,
@@ -38,7 +40,8 @@ func TestMigrateSelectedSwapAmount(t *testing.T) {
 
 		return did
 	}
-
+	_, pubClient := test.CreateKey(1)
+	_, pubServer := test.CreateKey(2)
 	d1, d2 := &deposit.Deposit{
 		ID: newID(),
 		OutPoint: wire.OutPoint{
@@ -49,6 +52,13 @@ func TestMigrateSelectedSwapAmount(t *testing.T) {
 		TimeOutSweepPkScript: []byte{
 			0x00, 0x14, 0x1a, 0x2b, 0x3c, 0x41,
 		},
+		AddressID: 1,
+		AddressParams: &address.Parameters{
+			ClientPubkey: pubClient,
+			ServerPubkey: pubServer,
+			PkScript:     []byte{0x00, 0x14, 0x1a, 0x2b, 0x3c},
+			Expiry:       10_000,
+		},
 	},
 		&deposit.Deposit{
 			ID: newID(),
@@ -60,9 +70,22 @@ func TestMigrateSelectedSwapAmount(t *testing.T) {
 			TimeOutSweepPkScript: []byte{
 				0x00, 0x14, 0x1a, 0x2b, 0x3c, 0x4d,
 			},
+			AddressID: 2,
+			AddressParams: &address.Parameters{
+				ClientPubkey: pubClient,
+				ServerPubkey: pubServer,
+				PkScript:     []byte{0x00, 0x14, 0x1a, 0x2b, 0x3d},
+				Expiry:       20_000,
+			},
 		}
 
-	err := depositStore.CreateDeposit(ctxb, d1)
+	err := addressStore.CreateStaticAddress(ctxb, d1.AddressParams)
+	require.NoError(t, err)
+
+	err = addressStore.CreateStaticAddress(ctxb, d2.AddressParams)
+	require.NoError(t, err)
+
+	err = depositStore.CreateDeposit(ctxb, d1)
 	require.NoError(t, err)
 	err = depositStore.CreateDeposit(ctxb, d2)
 	require.NoError(t, err)
diff --git a/staticaddr/loopin/sql_store.go b/staticaddr/loopin/sql_store.go
@@ -268,6 +268,11 @@ func (s *SqlStore) CreateLoopIn(ctx context.Context,
 	joinedOutpoints := strings.Join(
 		loopIn.DepositOutpoints, OutpointSeparator,
 	)
+
+	var changeAddress string
+	if loopIn.ChangeAddress != nil {
+		changeAddress = loopIn.ChangeAddress.String()
+	}
 	staticAddressLoopInParams := sqlc.InsertStaticAddressLoopInParams{
 		SwapHash:                loopIn.SwapHash[:],
 		SwapInvoice:             loopIn.SwapInvoice,
@@ -277,6 +282,7 @@ func (s *SqlStore) CreateLoopIn(ctx context.Context,
 		HtlcTxFeeRateSatKw:      int64(loopIn.HtlcTxFeeRate),
 		DepositOutpoints:        joinedOutpoints,
 		SelectedAmount:          int64(loopIn.SelectedAmount),
+		ChangeAddress:           changeAddress,
 		PaymentTimeoutSeconds:   int32(loopIn.PaymentTimeoutSeconds),
 		Fast:                    loopIn.Fast,
 	}
@@ -565,6 +571,16 @@ func toStaticAddressLoopIn(_ context.Context, network *chaincfg.Params,
 		depositList = append(depositList, deposit)
 	}
 
+	var changeAddress btcutil.Address
+	if swap.ChangeAddress != "" {
+		changeAddress, err = btcutil.DecodeAddress(
+			swap.ChangeAddress, network,
+		)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	loopIn := &StaticAddressLoopIn{
 		SwapHash:         swapHash,
 		SwapPreimage:     swapPreImage,
@@ -588,6 +604,7 @@ func toStaticAddressLoopIn(_ context.Context, network *chaincfg.Params,
 		QuotedSwapFee:         btcutil.Amount(swap.QuotedSwapFeeSatoshis),
 		DepositOutpoints:      depositOutpoints,
 		SelectedAmount:        btcutil.Amount(swap.SelectedAmount),
+		ChangeAddress:         changeAddress,
 		Fast:                  swap.Fast,
 		HtlcTxFeeRate: chainfee.SatPerKWeight(
 			swap.HtlcTxFeeRateSatKw,
diff --git a/swapserverrpc/staticaddr.pb.go b/swapserverrpc/staticaddr.pb.go
diff --git a/swapserverrpc/staticaddr.proto b/swapserverrpc/staticaddr.proto

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+ALTER TABLE static_address_swaps DROP COLUMN change_address;`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+-- change_address stores the change output address for the HTLC transaction of a`
	`2`	`+-- static address loop-in swap.`
	`3`	`+ALTER TABLE static_address_swaps ADD change_address TEXT NOT NULL DEFAULT '';`
Original file line number	Diff line number	Diff line change
`@@ -312,6 +312,9 @@ func newManagerTestContext(t testing.T) ManagerTestContext {`
`312`	`312`	`},`
`313`	`313`	`}`
`314`	`314`	`require.NoError(t, err)`
	`315`	`+`
	`316`	`+ _, clientPub := test.CreateKey(1)`
	`317`	`+ _, serverPub := test.CreateKey(2)`
`315`	`318`	`storedDeposits := []*Deposit{`
`316`	`319`	`{`
`317`	`320`	`ID: ID,`
`@@ -324,6 +327,9 @@ func newManagerTestContext(t testing.T) ManagerTestContext {`
`324`	`327`	`AddressParams: &address.Parameters{`
`325`	`328`	`ProtocolVersion: version.ProtocolVersion_V0,`
`326`	`329`	`Expiry: 100,`
	`330`	`+ ClientPubkey: clientPub,`
	`331`	`+ ServerPubkey: serverPub,`
	`332`	`+ PkScript: utxo.PkScript,`
`327`	`333`	`},`
`328`	`334`	`},`
`329`	`335`	`}`