multi: add aux leaf creator

config.go

@@ -10,6 +10,7 @@ import (
 	"github.com/lightninglabs/taproot-assets/monitoring"
 	"github.com/lightninglabs/taproot-assets/proof"
 	"github.com/lightninglabs/taproot-assets/rfq"
+	"github.com/lightninglabs/taproot-assets/tapchannel"
 	"github.com/lightninglabs/taproot-assets/tapdb"
 	"github.com/lightninglabs/taproot-assets/tapfreighter"
 	"github.com/lightninglabs/taproot-assets/tapgarden"
@@ -125,6 +126,8 @@ type Config struct {
 
 	UniverseStats universe.Telemetry
 
+	AuxLeafCreator *tapchannel.AuxLeafCreator
+
 	// UniversePublicAccess is flag which, If true, and the Universe server
 	// is on a public interface, valid proof from remote parties will be
 	// accepted, and proofs will be queryable by remote parties.

go.mod

@@ -33,6 +33,7 @@ require (
 	github.com/lightningnetwork/lnd v0.17.0-beta.rc6.0.20240501135111-81970eac6a5a
 	github.com/lightningnetwork/lnd/cert v1.2.2
 	github.com/lightningnetwork/lnd/clock v1.1.1
+	github.com/lightningnetwork/lnd/fn v1.0.5
 	github.com/lightningnetwork/lnd/tlv v1.2.6
 	github.com/lightningnetwork/lnd/tor v1.1.2
 	github.com/ory/dockertest/v3 v3.10.0
@@ -121,7 +122,6 @@ require (
 	github.com/lightninglabs/lightning-node-connect v0.2.5-alpha // indirect
 	github.com/lightninglabs/neutrino v0.16.0 // indirect
 	github.com/lightningnetwork/lightning-onion v1.2.1-0.20230823005744-06182b1d7d2f // indirect
-	github.com/lightningnetwork/lnd/fn v1.0.5 // indirect
 	github.com/lightningnetwork/lnd/healthcheck v1.2.4 // indirect
 	github.com/lightningnetwork/lnd/kvdb v1.4.6 // indirect
 	github.com/lightningnetwork/lnd/queue v1.1.1 // indirect

server.go

@@ -18,9 +18,14 @@ import (
 	"github.com/lightninglabs/taproot-assets/taprpc"
 	"github.com/lightningnetwork/lnd"
 	"github.com/lightningnetwork/lnd/build"
+	"github.com/lightningnetwork/lnd/channeldb"
+	lfn "github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/lncfg"
 	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/macaroons"
+	"github.com/lightningnetwork/lnd/tlv"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/keepalive"
 	"gopkg.in/macaroon-bakery.v2/bakery"
@@ -174,6 +179,11 @@ func (s *Server) initialize(interceptorChain *rpcperms.InterceptorChain) error {
 		return fmt.Errorf("unable to start RFQ manager: %w", err)
 	}
 
+	// Start the auxiliary leaf creator.
+	if err := s.cfg.AuxLeafCreator.Start(); err != nil {
+		return fmt.Errorf("unable to start aux leaf creator: %w", err)
+	}
+
 	if s.cfg.UniversePublicAccess {
 		err := s.cfg.UniverseFederation.SetAllowPublicAccess()
 		if err != nil {
@@ -610,6 +620,10 @@ func (s *Server) Stop() error {
 		return err
 	}
 
+	if err := s.cfg.AuxLeafCreator.Stop(); err != nil {
+		return err
+	}
+
 	if s.macaroonService != nil {
 		err := s.macaroonService.Stop()
 		if err != nil {
@@ -623,3 +637,98 @@ func (s *Server) Stop() error {
 
 	return nil
 }
+
+// A compile-time check to ensure that Server fully implements the
+// lnwallet.AuxLeafStore interface.
+var _ lnwallet.AuxLeafStore = (*Server)(nil)
+
+// FetchLeavesFromView attempts to fetch the auxiliary leaves that correspond to
+// the passed aux blob, and pending fully evaluated HTLC view.
+//
+// NOTE: This method is part of the lnwallet.AuxLeafStore interface.
+func (s *Server) FetchLeavesFromView(chanState *channeldb.OpenChannel,
+	prevBlob tlv.Blob, view *lnwallet.HtlcView, isOurCommit bool,
+	ourBalance, theirBalance lnwire.MilliSatoshi,
+	keys lnwallet.CommitmentKeyRing) (lfn.Option[lnwallet.CommitAuxLeaves],
+	lnwallet.CommitSortFunc, error) {
+
+	srvrLog.Debugf("FetchLeavesFromView called")
+
+	select {
+	case <-s.ready:
+	case <-s.quit:
+		return lfn.None[lnwallet.CommitAuxLeaves](), nil,
+			fmt.Errorf("tapd is shutting down")
+	}
+
+	return s.cfg.AuxLeafCreator.FetchLeavesFromView(
+		chanState, prevBlob, view, isOurCommit, ourBalance,
+		theirBalance, keys,
+	)
+}
+
+// FetchLeavesFromCommit attempts to fetch the auxiliary leaves that
+// correspond to the passed aux blob, and an existing channel
+// commitment.
+//
+// NOTE: This method is part of the lnwallet.AuxLeafStore interface.
+func (s *Server) FetchLeavesFromCommit(chanState *channeldb.OpenChannel,
+	com channeldb.ChannelCommitment,
+	keys lnwallet.CommitmentKeyRing) (lfn.Option[lnwallet.CommitAuxLeaves],
+	error) {
+
+	srvrLog.Debugf("FetchLeavesFromCommit called")
+
+	select {
+	case <-s.ready:
+	case <-s.quit:
+		return lfn.None[lnwallet.CommitAuxLeaves](),
+			fmt.Errorf("tapd is shutting down")
+	}
+
+	return s.cfg.AuxLeafCreator.FetchLeavesFromCommit(chanState, com, keys)
+}
+
+// FetchLeavesFromRevocation attempts to fetch the auxiliary leaves
+// from a channel revocation that stores balance + blob information.
+//
+// NOTE: This method is part of the lnwallet.AuxLeafStore interface.
+func (s *Server) FetchLeavesFromRevocation(
+	rev *channeldb.RevocationLog) (lfn.Option[lnwallet.CommitAuxLeaves],
+	error) {
+
+	srvrLog.Debugf("FetchLeavesFromRevocation called")
+
+	select {
+	case <-s.ready:
+	case <-s.quit:
+		return lfn.None[lnwallet.CommitAuxLeaves](),
+			fmt.Errorf("tapd is shutting down")
+	}
+
+	return s.cfg.AuxLeafCreator.FetchLeavesFromRevocation(rev)
+}
+
+// ApplyHtlcView serves as the state transition function for the custom
+// channel's blob. Given the old blob, and an HTLC view, then a new
+// blob should be returned that reflects the pending updates.
+//
+// NOTE: This method is part of the lnwallet.AuxLeafStore interface.
+func (s *Server) ApplyHtlcView(chanState *channeldb.OpenChannel,
+	prevBlob tlv.Blob, originalView *lnwallet.HtlcView, isOurCommit bool,
+	ourBalance, theirBalance lnwire.MilliSatoshi,
+	keys lnwallet.CommitmentKeyRing) (lfn.Option[tlv.Blob], error) {
+
+	srvrLog.Debugf("ApplyHtlcView called")
+
+	select {
+	case <-s.ready:
+	case <-s.quit:
+		return lfn.None[tlv.Blob](), fmt.Errorf("tapd is shutting down")
+	}
+
+	return s.cfg.AuxLeafCreator.ApplyHtlcView(
+		chanState, prevBlob, originalView, isOurCommit, ourBalance,
+		theirBalance, keys,
+	)
+}

tapcfg/server.go

@@ -14,6 +14,7 @@ import (
 	"github.com/lightninglabs/taproot-assets/asset"
 	"github.com/lightninglabs/taproot-assets/proof"
 	"github.com/lightninglabs/taproot-assets/rfq"
+	"github.com/lightninglabs/taproot-assets/tapchannel"
 	"github.com/lightninglabs/taproot-assets/tapdb"
 	"github.com/lightninglabs/taproot-assets/tapdb/sqlc"
 	"github.com/lightninglabs/taproot-assets/tapfreighter"
@@ -340,6 +341,12 @@ func genServerConfig(cfg *Config, cfgLogger btclog.Logger,
 		return nil, err
 	}
 
+	auxLeafCreator := tapchannel.NewAuxLeafCreator(
+		&tapchannel.LeafCreatorConfig{
+			ChainParams: &tapChainParams,
+		},
+	)
+
 	return &tap.Config{
 		DebugLevel:   cfg.DebugLevel,
 		RuntimeID:    runtimeID,
@@ -413,6 +420,7 @@ func genServerConfig(cfg *Config, cfgLogger btclog.Logger,
 		UniverseQueriesPerSecond: cfg.Universe.UniverseQueriesPerSecond,
 		UniverseQueriesBurst:     cfg.Universe.UniverseQueriesBurst,
 		RfqManager:               rfqManager,
+		AuxLeafCreator:           auxLeafCreator,
 		LogWriter:                cfg.LogWriter,
 		DatabaseConfig: &tap.DatabaseConfig{
 			RootKeyStore: tapdb.NewRootKeyStore(rksDB),