tapchannel: check for feature bits before opening chans

feature_bit_verifier.go

@@ -0,0 +1,54 @@
+package taprootassets
+
+import (
+	"context"
+
+	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/lightninglabs/lndclient"
+	"github.com/lightninglabs/taproot-assets/tapchannel"
+	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/lightningnetwork/lnd/routing/route"
+)
+
+// LndFeatureBitVerifier is a struct that verifies that the feature bits of a
+// target connected peer, using our registered lnd node.
+type LndFeatureBitVerifier struct {
+	lnd *lndclient.LndServices
+}
+
+// NewLndFeatureBitVerifier creates a new LndFeatureBitVerifier instance.
+func NewLndFeatureBitVerifier(
+	lnd *lndclient.LndServices) *LndFeatureBitVerifier {
+
+	return &LndFeatureBitVerifier{
+		lnd: lnd,
+	}
+}
+
+// HasFeature returns true if the peer has the given feature bit set. If the
+// peer can't be found, then ErrNoPeer is returned.
+func (l *LndFeatureBitVerifier) HasFeature(ctx context.Context,
+	peerPub btcec.PublicKey, bit lnwire.FeatureBit) (bool, error) {
+
+	peerBytes := route.NewVertex(&peerPub)
+
+	peers, err := l.lnd.Client.ListPeers(ctx)
+	if err != nil {
+		return false, err
+	}
+
+	for _, peer := range peers {
+		if peer.Pubkey != peerBytes {
+			continue
+		}
+
+		return peer.Features.HasFeature(bit), nil
+	}
+
+	// If we get to this point, we weren't able to find the peer.
+	return false, tapchannel.ErrNoPeer
+}
+
+// A compile-time check to ensure that LndFeatureBitVerifier implements the
+// FeatureBitVerifier interface.
+var _ tapchannel.FeatureBitVerifer = (*LndFeatureBitVerifier)(nil)

go.mod

@@ -28,7 +28,7 @@ require (
 	github.com/lib/pq v1.10.9
 	github.com/lightninglabs/aperture v0.1.21-beta.0.20230705004936-87bb996a4030
 	github.com/lightninglabs/lightning-node-connect/hashmailrpc v1.0.2
-	github.com/lightninglabs/lndclient v1.0.1-0.20240607082608-4ce52a1a3f27
+	github.com/lightninglabs/lndclient v1.0.1-0.20240723001046-925d3c8297bf
 	github.com/lightninglabs/neutrino/cache v1.1.2
 	github.com/lightningnetwork/lnd v0.18.0-beta.rc4.0.20240723043204-f09d4042aee4
 	github.com/lightningnetwork/lnd/cert v1.2.2

go.sum

@@ -480,8 +480,8 @@ github.com/lightninglabs/lightning-node-connect v0.2.5-alpha h1:ZRVChwczFXK0CEbx
 github.com/lightninglabs/lightning-node-connect v0.2.5-alpha/go.mod h1:A9Pof9fETkH+F67BnOmrBDThPKstqp73wlImWOZvTXQ=
 github.com/lightninglabs/lightning-node-connect/hashmailrpc v1.0.2 h1:Er1miPZD2XZwcfE4xoS5AILqP1mj7kqnhbBSxW9BDxY=
 github.com/lightninglabs/lightning-node-connect/hashmailrpc v1.0.2/go.mod h1:antQGRDRJiuyQF6l+k6NECCSImgCpwaZapATth2Chv4=
-github.com/lightninglabs/lndclient v1.0.1-0.20240607082608-4ce52a1a3f27 h1:vm8a13EzH2Qe6j4eZx+tHPeEVoNhJ7coihFPX6K2kco=
-github.com/lightninglabs/lndclient v1.0.1-0.20240607082608-4ce52a1a3f27/go.mod h1:bxd2a15cIaW8KKcmOf9nNDI/GTxxj0upEYs1EIkttqw=
+github.com/lightninglabs/lndclient v1.0.1-0.20240723001046-925d3c8297bf h1:VcTK/juPtAqwEBckCcSHCsVRSbHGbWtDZgnXL5JOLkg=
+github.com/lightninglabs/lndclient v1.0.1-0.20240723001046-925d3c8297bf/go.mod h1:bxd2a15cIaW8KKcmOf9nNDI/GTxxj0upEYs1EIkttqw=
 github.com/lightninglabs/neutrino v0.16.1-0.20240425105051-602843d34ffd h1:D8aRocHpoCv43hL8egXEMYyPmyOiefFHZ66338KQB2s=
 github.com/lightninglabs/neutrino v0.16.1-0.20240425105051-602843d34ffd/go.mod h1:x3OmY2wsA18+Kc3TSV2QpSUewOCiscw2mKpXgZv2kZk=
 github.com/lightninglabs/neutrino/cache v1.1.2 h1:C9DY/DAPaPxbFC+xNNEI/z1SJY9GS3shmlu5hIQ798g=

tapcfg/server.go

@@ -102,6 +102,7 @@ func genServerConfig(cfg *Config, cfgLogger btclog.Logger,
 	msgTransportClient := tap.NewLndMsgTransportClient(lndServices)
 	lndRouterClient := tap.NewLndRouterClient(lndServices)
 	lndInvoicesClient := tap.NewLndInvoicesClient(lndServices)
+	lndFeatureBitsVerifier := tap.NewLndFeatureBitVerifier(lndServices)
 
 	uniDB := tapdb.NewTransactionExecutor(
 		db, func(tx *sql.Tx) tapdb.BaseUniverseStore {
@@ -434,6 +435,7 @@ func genServerConfig(cfg *Config, cfgLogger btclog.Logger,
 			TxSender:           chainPorter,
 			DefaultCourierAddr: proofCourierAddr,
 			AssetSyncer:        addrBook,
+			FeatureBits:        lndFeatureBitsVerifier,
 		},
 	)
 	auxTrafficShaper := tapchannel.NewAuxTrafficShaper(

tapchannel/aux_funding_controller.go

@@ -70,6 +70,18 @@ type PeerMessenger interface {
 		msg lnwire.Message) error
 }
 
+// ErrNoPeer is returned when a peer can't be found.
+var ErrNoPeer = errors.New("peer not found")
+
+// FeatureBitVerifer is an interface that allows us to verify that a peer has a
+// given feature bit set.
+type FeatureBitVerifer interface {
+	// HasFeature returns true if the peer has the given feature bit set.
+	// If the peer can't be found, then ErrNoPeer is returned.
+	HasFeature(ctx context.Context, peerPub btcec.PublicKey,
+		bit lnwire.FeatureBit) (bool, error)
+}
+
 // OpenChanReq is a request to open a new asset channel with a remote peer.
 type OpenChanReq struct {
 	// ChanAmt is the amount of BTC to put into the channel. Some BTC is
@@ -200,6 +212,10 @@ type FundingControllerCfg struct {
 	// AssetSyncer is used to ensure that we've already verified the asset
 	// genesis for any assets used within channels.
 	AssetSyncer AssetSyncer
+
+	// FeatureBits is used to verify that the peer has the required feature
+	// to fund asset channels.
+	FeatureBits FeatureBitVerifer
 }
 
 // bindFundingReq is a request to bind a pending channel ID to a complete aux
@@ -1321,6 +1337,21 @@ func (f *FundingController) processFundingMsg(ctx context.Context,
 func (f *FundingController) processFundingReq(fundingFlows fundingFlowIndex,
 	fundReq *FundReq) error {
 
+	// Before we even attempt funding, let's make sure that the remote peer
+	// actually supports the feature bit.
+	supportsAssetChans, err := f.cfg.FeatureBits.HasFeature(
+		fundReq.ctx, fundReq.PeerPub,
+		lnwire.SimpleTaprootOverlayChansOptional,
+	)
+	if err != nil {
+		return fmt.Errorf("unable to query peer feature bits: %w", err)
+	}
+
+	if !supportsAssetChans {
+		return fmt.Errorf("peer %x does not support asset channels",
+			fundReq.PeerPub.SerializeCompressed())
+	}
+
 	// To start, we'll make a new pending asset funding desc. This'll be
 	// our scratch pad during the asset funding process.
 	tempPID, err := newPendingChanID()