multi: distinguish between htlc in and out constraints

chainregistry.go

@@ -130,6 +130,8 @@ type chainControl struct {
 	wallet *lnwallet.LightningWallet
 
 	routingPolicy htlcswitch.ForwardingPolicy
+
+	minHtlcIn lnwire.MilliSatoshi
 }
 
 // newChainControlFromConfig attempts to create a chainControl instance
@@ -157,21 +159,23 @@ func newChainControlFromConfig(cfg *config, chanDB *channeldb.DB,
 	switch registeredChains.PrimaryChain() {
 	case bitcoinChain:
 		cc.routingPolicy = htlcswitch.ForwardingPolicy{
-			MinHTLC:       cfg.Bitcoin.MinHTLC,
+			MinHTLCOut:    cfg.Bitcoin.MinHTLC,
 			BaseFee:       cfg.Bitcoin.BaseFee,
 			FeeRate:       cfg.Bitcoin.FeeRate,
 			TimeLockDelta: cfg.Bitcoin.TimeLockDelta,
 		}
+		cc.minHtlcIn = cfg.Bitcoin.MinHTLC
 		cc.feeEstimator = chainfee.NewStaticEstimator(
 			defaultBitcoinStaticFeePerKW, 0,
 		)
 	case litecoinChain:
 		cc.routingPolicy = htlcswitch.ForwardingPolicy{
-			MinHTLC:       cfg.Litecoin.MinHTLC,
+			MinHTLCOut:    cfg.Litecoin.MinHTLC,
 			BaseFee:       cfg.Litecoin.BaseFee,
 			FeeRate:       cfg.Litecoin.FeeRate,
 			TimeLockDelta: cfg.Litecoin.TimeLockDelta,
 		}
+		cc.minHtlcIn = cfg.Litecoin.MinHTLC
 		cc.feeEstimator = chainfee.NewStaticEstimator(
 			defaultLitecoinStaticFeePerKW, 0,
 		)

fundingmanager.go

@@ -285,6 +285,10 @@ type fundingConfig struct {
 	// initially announcing channels.
 	DefaultRoutingPolicy htlcswitch.ForwardingPolicy
 
+	// DefaultMinHtlcIn is the default minimum incoming htlc value that is
+	// set as a channel parameter.
+	DefaultMinHtlcIn lnwire.MilliSatoshi
+
 	// NumRequiredConfs is a function closure that helps the funding
 	// manager decide how many confirmations it should require for a
 	// channel extended to it. The function is able to take into account
@@ -1300,7 +1304,7 @@ func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
 	chanReserve := f.cfg.RequiredRemoteChanReserve(amt, msg.DustLimit)
 	maxValue := f.cfg.RequiredRemoteMaxValue(amt)
 	maxHtlcs := f.cfg.RequiredRemoteMaxHTLCs(amt)
-	minHtlc := f.cfg.DefaultRoutingPolicy.MinHTLC
+	minHtlc := f.cfg.DefaultMinHtlcIn
 
 	// Once the reservation has been created successfully, we add it to
 	// this peer's map of pending reservations to track this particular
@@ -2806,7 +2810,7 @@ func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) {
 	var (
 		peerKey        = msg.peer.IdentityKey()
 		localAmt       = msg.localFundingAmt
-		minHtlc        = msg.minHtlc
+		minHtlcIn      = msg.minHtlcIn
 		remoteCsvDelay = msg.remoteCsvDelay
 	)
 
@@ -2922,8 +2926,8 @@ func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) {
 	}
 
 	// If no minimum HTLC value was specified, use the default one.
-	if minHtlc == 0 {
+	if minHtlcIn == 0 {
-		minHtlc = f.cfg.DefaultRoutingPolicy.MinHTLC
+		minHtlcIn = f.cfg.DefaultMinHtlcIn
 	}
 
 	// If a pending channel map for this peer isn't already created, then
@@ -2938,7 +2942,7 @@ func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) {
 	resCtx := &reservationWithCtx{
 		chanAmt:        capacity,
 		remoteCsvDelay: remoteCsvDelay,
-		remoteMinHtlc:  minHtlc,
+		remoteMinHtlc:  minHtlcIn,
 		reservation:    reservation,
 		peer:           msg.peer,
 		updates:        msg.updates,
@@ -2972,7 +2976,7 @@ func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) {
 		DustLimit:             ourContribution.DustLimit,
 		MaxValueInFlight:      maxValue,
 		ChannelReserve:        chanReserve,
-		HtlcMinimum:           minHtlc,
+		HtlcMinimum:           minHtlcIn,
 		FeePerKiloWeight:      uint32(commitFeePerKw),
 		CsvDelay:              remoteCsvDelay,
 		MaxAcceptedHTLCs:      maxHtlcs,

fundingmanager_test.go

@@ -336,11 +336,12 @@ func createTestFundingManager(t *testing.T, privKey *btcec.PrivateKey,
 			return nil, fmt.Errorf("unable to find channel")
 		},
 		DefaultRoutingPolicy: htlcswitch.ForwardingPolicy{
-			MinHTLC:       5,
+			MinHTLCOut:    5,
 			BaseFee:       100,
 			FeeRate:       1000,
 			TimeLockDelta: 10,
 		},
+		DefaultMinHtlcIn: 5,
 		NumRequiredConfs: func(chanAmt btcutil.Amount,
 			pushAmt lnwire.MilliSatoshi) uint16 {
 			return 3
@@ -464,11 +465,12 @@ func recreateAliceFundingManager(t *testing.T, alice *testNode) {
 		TempChanIDSeed: oldCfg.TempChanIDSeed,
 		FindChannel:    oldCfg.FindChannel,
 		DefaultRoutingPolicy: htlcswitch.ForwardingPolicy{
-			MinHTLC:       5,
+			MinHTLCOut:    5,
 			BaseFee:       100,
 			FeeRate:       1000,
 			TimeLockDelta: 10,
 		},
+		DefaultMinHtlcIn:       5,
 		RequiredRemoteMaxValue: oldCfg.RequiredRemoteMaxValue,
 		PublishTransaction: func(txn *wire.MsgTx) error {
 			publishChan <- txn
@@ -926,7 +928,7 @@ func assertChannelAnnouncements(t *testing.T, alice, bob *testNode,
 				// _other_ node.
 				other := (j + 1) % 2
 				minHtlc := nodes[other].fundingMgr.cfg.
-					DefaultRoutingPolicy.MinHTLC
+					DefaultMinHtlcIn
 
 				// We might expect a custom MinHTLC value.
 				if len(customMinHtlc) > 0 {
@@ -2325,7 +2327,7 @@ func TestFundingManagerCustomChannelParameters(t *testing.T) {
 
 	// This is the custom parameters we'll use.
 	const csvDelay = 67
-	const minHtlc = 1234
+	const minHtlcIn = 1234
 
 	// We will consume the channel updates as we go, so no buffering is
 	// needed.
@@ -2344,7 +2346,7 @@ func TestFundingManagerCustomChannelParameters(t *testing.T) {
 		localFundingAmt: localAmt,
 		pushAmt:         lnwire.NewMSatFromSatoshis(pushAmt),
 		private:         false,
-		minHtlc:         minHtlc,
+		minHtlcIn:       minHtlcIn,
 		remoteCsvDelay:  csvDelay,
 		updates:         updateChan,
 		err:             errChan,
@@ -2381,9 +2383,9 @@ func TestFundingManagerCustomChannelParameters(t *testing.T) {
 	}
 
 	// Check that the custom minHTLC value is sent.
-	if openChannelReq.HtlcMinimum != minHtlc {
+	if openChannelReq.HtlcMinimum != minHtlcIn {
 		t.Fatalf("expected OpenChannel to have minHtlc %v, got %v",
-			minHtlc, openChannelReq.HtlcMinimum)
+			minHtlcIn, openChannelReq.HtlcMinimum)
 	}
 
 	chanID := openChannelReq.PendingChannelID
@@ -2468,7 +2470,7 @@ func TestFundingManagerCustomChannelParameters(t *testing.T) {
 
 	// The minimum HTLC value Alice can offer should be 5, and the minimum
 	// Bob can offer should be 1234.
-	if err := assertMinHtlc(resCtx, 5, minHtlc); err != nil {
+	if err := assertMinHtlc(resCtx, 5, minHtlcIn); err != nil {
 		t.Fatal(err)
 	}
 
@@ -2482,7 +2484,7 @@ func TestFundingManagerCustomChannelParameters(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if err := assertMinHtlc(resCtx, minHtlc, 5); err != nil {
+	if err := assertMinHtlc(resCtx, minHtlcIn, 5); err != nil {
 		t.Fatal(err)
 	}
 
@@ -2543,7 +2545,7 @@ func TestFundingManagerCustomChannelParameters(t *testing.T) {
 	// announcements. Alice should advertise the default MinHTLC value of
 	// 5, while bob should advertise the value minHtlc, since Alice
 	// required him to use it.
-	assertChannelAnnouncements(t, alice, bob, capacity, 5, minHtlc)
+	assertChannelAnnouncements(t, alice, bob, capacity, 5, minHtlcIn)
 
 	// The funding transaction is now confirmed, wait for the
 	// OpenStatusUpdate_ChanOpen update

htlcswitch/link.go

@@ -71,10 +71,8 @@ const (
 // the error possibly carrying along a ChannelUpdate message that includes the
 // latest policy.
 type ForwardingPolicy struct {
-	// MinHTLC is the smallest HTLC that is to be forwarded. This is
+	// MinHTLC is the smallest HTLC that is to be forwarded.
-	// set when a channel is first opened, and will be static for the
+	MinHTLCOut lnwire.MilliSatoshi
-	// lifetime of the channel.
-	MinHTLC lnwire.MilliSatoshi
 
 	// MaxHTLC is the largest HTLC that is to be forwarded.
 	MaxHTLC lnwire.MilliSatoshi
@@ -2218,9 +2216,9 @@ func (l *channelLink) canSendHtlc(policy ForwardingPolicy,
 	// As our first sanity check, we'll ensure that the passed HTLC isn't
 	// too small for the next hop. If so, then we'll cancel the HTLC
 	// directly.
-	if amt < policy.MinHTLC {
+	if amt < policy.MinHTLCOut {
 		l.log.Errorf("outgoing htlc(%x) is too small: min_htlc=%v, "+
-			"htlc_value=%v", payHash[:], policy.MinHTLC,
+			"htlc_value=%v", payHash[:], policy.MinHTLCOut,
 			amt)
 
 		// As part of the returned error, we'll send our latest routing

htlcswitch/link_test.go

@@ -1694,7 +1694,7 @@ func newSingleLinkTestHarness(chanAmt, chanReserve btcutil.Amount) (
 			quit:     make(chan struct{}),
 		}
 		globalPolicy = ForwardingPolicy{
-			MinHTLC:       lnwire.NewMSatFromSatoshis(5),
+			MinHTLCOut:    lnwire.NewMSatFromSatoshis(5),
 			MaxHTLC:       lnwire.NewMSatFromSatoshis(chanAmt),
 			BaseFee:       lnwire.NewMSatFromSatoshis(1),
 			TimeLockDelta: 6,
@@ -4253,7 +4253,7 @@ func (h *persistentLinkHarness) restartLink(
 		}
 
 		globalPolicy = ForwardingPolicy{
-			MinHTLC:       lnwire.NewMSatFromSatoshis(5),
+			MinHTLCOut:    lnwire.NewMSatFromSatoshis(5),
 			BaseFee:       lnwire.NewMSatFromSatoshis(1),
 			TimeLockDelta: 6,
 		}
@@ -5512,7 +5512,7 @@ func TestCheckHtlcForward(t *testing.T) {
 		cfg: ChannelLinkConfig{
 			FwrdingPolicy: ForwardingPolicy{
 				TimeLockDelta: 20,
-				MinHTLC:       500,
+				MinHTLCOut:    500,
 				MaxHTLC:       1000,
 				BaseFee:       10,
 			},

htlcswitch/test_utils.go

@@ -1078,7 +1078,7 @@ func newHopNetwork() *hopNetwork {
 	defaultDelta := uint32(6)
 
 	globalPolicy := ForwardingPolicy{
-		MinHTLC:       lnwire.NewMSatFromSatoshis(5),
+		MinHTLCOut:    lnwire.NewMSatFromSatoshis(5),
 		BaseFee:       lnwire.NewMSatFromSatoshis(1),
 		TimeLockDelta: defaultDelta,
 	}

peer.go

@@ -531,7 +531,7 @@ func (p *peer) loadActiveChannels(chans []*channeldb.OpenChannel) (
 		var forwardingPolicy *htlcswitch.ForwardingPolicy
 		if selfPolicy != nil {
 			forwardingPolicy = &htlcswitch.ForwardingPolicy{
-				MinHTLC:       selfPolicy.MinHTLC,
+				MinHTLCOut:    selfPolicy.MinHTLC,
 				MaxHTLC:       selfPolicy.MaxHTLC,
 				BaseFee:       selfPolicy.FeeBaseMSat,
 				FeeRate:       selfPolicy.FeeProportionalMillionths,
@@ -1862,7 +1862,7 @@ out:
 			fwdMinHtlc := lnChan.FwdMinHtlc()
 			defaultPolicy := p.server.cc.routingPolicy
 			forwardingPolicy := &htlcswitch.ForwardingPolicy{
-				MinHTLC:       fwdMinHtlc,
+				MinHTLCOut:    fwdMinHtlc,
 				MaxHTLC:       newChan.LocalChanCfg.MaxPendingAmount,
 				BaseFee:       defaultPolicy.BaseFee,
 				FeeRate:       defaultPolicy.FeeRate,

pilot.go

@@ -92,7 +92,7 @@ func (c *chanController) OpenChannel(target *btcec.PublicKey,
 	}
 
 	// TODO(halseth): make configurable?
-	minHtlc := lnwire.NewMSatFromSatoshis(1)
+	minHtlcIn := lnwire.NewMSatFromSatoshis(1)
 
 	// Construct the open channel request and send it to the server to begin
 	// the funding workflow.
@@ -102,7 +102,7 @@ func (c *chanController) OpenChannel(target *btcec.PublicKey,
 		subtractFees:    true,
 		localFundingAmt: amt,
 		pushAmt:         0,
-		minHtlc:         minHtlc,
+		minHtlcIn:       minHtlcIn,
 		fundingFeePerKw: feePerKw,
 		private:         c.private,
 		remoteCsvDelay:  0,

routing/localchans/manager.go

@@ -93,7 +93,7 @@ func (r *Manager) UpdatePolicy(newSchema routing.ChannelPolicy,
 			BaseFee:       edge.FeeBaseMSat,
 			FeeRate:       edge.FeeProportionalMillionths,
 			TimeLockDelta: uint32(edge.TimeLockDelta),
-			MinHTLC:       edge.MinHTLC,
+			MinHTLCOut:    edge.MinHTLC,
 			MaxHTLC:       edge.MaxHTLC,
 		}
 

rpcserver.go

@@ -1449,7 +1449,7 @@ func (r *rpcServer) OpenChannel(in *lnrpc.OpenChannelRequest,
 
 	localFundingAmt := btcutil.Amount(in.LocalFundingAmount)
 	remoteInitialBalance := btcutil.Amount(in.PushSat)
-	minHtlc := lnwire.MilliSatoshi(in.MinHtlcMsat)
+	minHtlcIn := lnwire.MilliSatoshi(in.MinHtlcMsat)
 	remoteCsvDelay := uint16(in.RemoteCsvDelay)
 
 	// Ensure that the initial balance of the remote party (if pushing
@@ -1537,7 +1537,7 @@ func (r *rpcServer) OpenChannel(in *lnrpc.OpenChannelRequest,
 		chainHash:       *activeNetParams.GenesisHash,
 		localFundingAmt: localFundingAmt,
 		pushAmt:         lnwire.NewMSatFromSatoshis(remoteInitialBalance),
-		minHtlc:         minHtlc,
+		minHtlcIn:       minHtlcIn,
 		fundingFeePerKw: feeRate,
 		private:         in.Private,
 		remoteCsvDelay:  remoteCsvDelay,
@@ -1631,7 +1631,7 @@ func (r *rpcServer) OpenChannelSync(ctx context.Context,
 
 	localFundingAmt := btcutil.Amount(in.LocalFundingAmount)
 	remoteInitialBalance := btcutil.Amount(in.PushSat)
-	minHtlc := lnwire.MilliSatoshi(in.MinHtlcMsat)
+	minHtlcIn := lnwire.MilliSatoshi(in.MinHtlcMsat)
 	remoteCsvDelay := uint16(in.RemoteCsvDelay)
 
 	// Ensure that the initial balance of the remote party (if pushing
@@ -1679,7 +1679,7 @@ func (r *rpcServer) OpenChannelSync(ctx context.Context,
 		chainHash:       *activeNetParams.GenesisHash,
 		localFundingAmt: localFundingAmt,
 		pushAmt:         lnwire.NewMSatFromSatoshis(remoteInitialBalance),
-		minHtlc:         minHtlc,
+		minHtlcIn:       minHtlcIn,
 		fundingFeePerKw: feeRate,
 		private:         in.Private,
 		remoteCsvDelay:  remoteCsvDelay,

server.go

@@ -985,6 +985,7 @@ func newServer(listenAddrs []net.Addr, chanDB *channeldb.DB,
 			return nil, fmt.Errorf("unable to find channel")
 		},
 		DefaultRoutingPolicy: cc.routingPolicy,
+		DefaultMinHtlcIn:     cc.minHtlcIn,
 		NumRequiredConfs: func(chanAmt btcutil.Amount,
 			pushAmt lnwire.MilliSatoshi) uint16 {
 			// For large channels we increase the number
@@ -3084,8 +3085,8 @@ type openChanReq struct {
 
 	private bool
 
-	// minHtlc is the minimum incoming htlc that we accept.
+	// minHtlcIn is the minimum incoming htlc that we accept.
-	minHtlc lnwire.MilliSatoshi
+	minHtlcIn lnwire.MilliSatoshi
 
 	remoteCsvDelay uint16