liquidity: xpub support for autoloop

liquidity/liquidity.go

@@ -157,6 +157,15 @@ var (
 	// set together are specified.
 	ErrExclusiveRules = errors.New("channel and peer rules must be " +
 		"exclusive")
+
+	// ErrAmbiguousDestAddr is returned when a destination address and
+	// a extended public key account is set.
+	ErrAmbiguousDestAddr = errors.New("ambiguous destination address")
+
+	// ErrAccountAndAddrType indicates if an account is set but the
+	// account address type is not or vice versa.
+	ErrAccountAndAddrType = errors.New("account and address type have " +
+		"to be both either set or unset")
 )
 
 // Config contains the external functionality required to run the

liquidity/loopout_builder.go

@@ -154,9 +154,15 @@ func (b *loopOutBuilder) buildSwap(ctx context.Context, pubkey route.Vertex,
 			request.Label = labels.EasyAutoloopLabel(swap.TypeOut)
 		}
 
+		account := ""
+		addrType := walletrpc.AddressType_WITNESS_PUBKEY_HASH
+		if len(params.Account) > 0 {
+			account = params.Account
+			addrType = params.AccountAddrType
+		}
+
 		addr, err := b.cfg.Lnd.WalletKit.NextAddr(
-			ctx, "", walletrpc.AddressType_WITNESS_PUBKEY_HASH,
-			false,
+			ctx, account, addrType, false,
 		)
 		if err != nil {
 			return nil, err

liquidity/parameters.go

@@ -3,6 +3,7 @@ package liquidity
 import (
 	"errors"
 	"fmt"
+	"github.com/lightningnetwork/lnd/lnrpc/walletrpc"
 	"strings"
 	"time"
 
@@ -42,10 +43,18 @@ type Parameters struct {
 	// Autoloop enables automatic dispatch of swaps.
 	Autoloop bool
 
-	// DestAddr is the address to be used for sweeping the on-chain HTLC that
-	// is related with a loop out.
+	// DestAddr is the address to be used for sweeping the on-chain HTLC
+	// that is related with a loop out.
 	DestAddr btcutil.Address
 
+	// An alternative destination address source for the swap. This field
+	// represents the name of the account in the backing lnd instance.
+	// Refer to lnd's wallet import functions for reference.
+	Account string
+
+	// The address type of the account specified in the account field.
+	AccountAddrType walletrpc.AddressType
+
 	// AutoFeeBudget is the total amount we allow to be spent on
 	// automatically dispatched swaps. Once this budget has been used, we
 	// will stop dispatching swaps until the budget is refreshed.
@@ -227,6 +236,21 @@ func (p Parameters) validate(minConfs int32, openChans []lndclient.ChannelInfo,
 		return ErrZeroInFlight
 	}
 
+	// Destination address and account cannot be set at the same time.
+	if p.DestAddr != nil && len(p.DestAddr.String()) > 0 &&
+		len(p.Account) > 0 {
+
+		return ErrAmbiguousDestAddr
+	}
+
+	// If an account is specified the respective address type must be
+	// specified as well, or both must be unset.
+	if len(p.Account) == 0 !=
+		(p.AccountAddrType == walletrpc.AddressType_UNKNOWN) {
+
+		return ErrAccountAndAddrType
+	}
+
 	err := validateRestrictions(server, &p.ClientRestrictions)
 	if err != nil {
 		return err
@@ -376,13 +400,20 @@ func RpcToParameters(req *clientrpc.LiquidityParameters) (*Parameters,
 		if req.AutoloopDestAddress == "default" {
 			destaddr = nil
 		} else {
-			destaddr, err = btcutil.DecodeAddress(req.AutoloopDestAddress, nil)
+			destaddr, err = btcutil.DecodeAddress(
+				req.AutoloopDestAddress, nil,
+			)
 			if err != nil {
 				return nil, err
 			}
 		}
 	}
 
+	addrType := walletrpc.AddressType_UNKNOWN
+	if req.AccountAddrType == clientrpc.AddressType_TAPROOT_PUBKEY {
+		addrType = walletrpc.AddressType_TAPROOT_PUBKEY
+	}
+
 	params := &Parameters{
 		FeeLimit:        feeLimit,
 		SweepConfTarget: req.SweepConfTarget,
@@ -393,6 +424,8 @@ func RpcToParameters(req *clientrpc.LiquidityParameters) (*Parameters,
 			int64(req.AutoloopBudgetLastRefresh), 0,
 		),
 		DestAddr:        destaddr,
+		Account:         req.Account,
+		AccountAddrType: addrType,
 		AutoFeeBudget:   btcutil.Amount(req.AutoloopBudgetSat),
 		MaxAutoInFlight: int(req.AutoMaxInFlight),
 		ChannelRules: make(
@@ -487,6 +520,16 @@ func ParametersToRpc(cfg Parameters) (*clientrpc.LiquidityParameters,
 		destaddr = cfg.DestAddr.String()
 	}
 
+	var addrType clientrpc.AddressType
+	switch cfg.AccountAddrType {
+	case walletrpc.AddressType_TAPROOT_PUBKEY:
+		addrType = clientrpc.AddressType_TAPROOT_PUBKEY
+
+	default:
+		addrType = clientrpc.AddressType_ADDRESS_TYPE_UNKNOWN
+
+	}
+
 	rpcCfg := &clientrpc.LiquidityParameters{
 		SweepConfTarget:   cfg.SweepConfTarget,
 		FailureBackoffSec: uint64(cfg.FailureBackOff.Seconds()),
@@ -512,6 +555,8 @@ func ParametersToRpc(cfg Parameters) (*clientrpc.LiquidityParameters,
 		HtlcConfTarget:             cfg.HtlcConfTarget,
 		EasyAutoloop:               cfg.EasyAutoloop,
 		EasyAutoloopLocalTargetSat: uint64(cfg.EasyAutoloopTarget),
+		Account:                    cfg.Account,
+		AccountAddrType:            addrType,
 	}
 
 	switch f := cfg.FeeLimit.(type) {