htlcswitch/hop: move hop.Exit and hop.Source to hop pkg

htlcswitch/circuit_map.go

@@ -9,6 +9,7 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/go-errors/errors"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/htlcswitch/hop"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -311,7 +312,7 @@ func (cm *circuitMap) restoreMemState() error {
 			// documented case of stray keystones emerges for
 			// forwarded payments, this check should be removed, but
 			// with extreme caution.
-			if strayKeystone.OutKey.ChanID != sourceHop {
+			if strayKeystone.OutKey.ChanID != hop.Source {
 				continue
 			}
 
@@ -396,9 +397,9 @@ func (cm *circuitMap) trimAllOpenCircuits() error {
 
 		// First, skip any channels that have not been assigned their
 		// final channel identifier, otherwise we would try to trim
-		// htlcs belonging to the all-zero, sourceHop ID.
+		// htlcs belonging to the all-zero, hop.Source ID.
 		chanID := activeChannel.ShortChanID()
-		if chanID == sourceHop {
+		if chanID == hop.Source {
 			continue
 		}
 

htlcswitch/hop/type.go

@@ -0,0 +1,13 @@
+package hop
+
+import "github.com/lightningnetwork/lnd/lnwire"
+
+var (
+	// Exit is a special "hop" denoting that an incoming HTLC is meant to
+	// pay finally to the receiving node.
+	Exit lnwire.ShortChannelID
+
+	// Source is a sentinel "hop" denoting that an incoming HTLC is
+	// initiated by our own switch.
+	Source lnwire.ShortChannelID
+)

htlcswitch/iterator.go

@@ -14,16 +14,6 @@ import (
 	"github.com/lightningnetwork/lnd/tlv"
 )
 
-var (
-	// exitHop is a special "hop" which denotes that an incoming HTLC is
-	// meant to pay finally to the receiving node.
-	exitHop lnwire.ShortChannelID
-
-	// sourceHop is a sentinel value denoting that an incoming HTLC is
-	// initiated by our own switch.
-	sourceHop lnwire.ShortChannelID
-)
-
 // HopIterator is an interface that abstracts away the routing information
 // included in HTLC's which includes the entirety of the payment path of an
 // HTLC. This interface provides two basic method which carry out: how to
@@ -109,7 +99,7 @@ func (r *sphinxHopIterator) ForwardingInstructions() (
 
 		switch r.processedPacket.Action {
 		case sphinx.ExitNode:
-			nextHop = exitHop
+			nextHop = hop.Exit
 		case sphinx.MoreHops:
 			s := binary.BigEndian.Uint64(fwdInst.NextAddress[:])
 			nextHop = lnwire.NewShortChanIDFromInt(s)

htlcswitch/link.go

@@ -437,8 +437,8 @@ func (l *channelLink) Start() error {
 	// off point, since all indexes below that are committed. This action
 	// is only performed if the link's final short channel ID has been
 	// assigned, otherwise we would try to trim the htlcs belonging to the
-	// all-zero, sourceHop ID.
-	if l.ShortChanID() != sourceHop {
+	// all-zero, hop.Source ID.
+	if l.ShortChanID() != hop.Source {
 		localHtlcIndex, err := l.channel.NextLocalHtlcIndex()
 		if err != nil {
 			return fmt.Errorf("unable to retrieve next local "+
@@ -536,7 +536,7 @@ func (l *channelLink) WaitForShutdown() {
 // the all-zero source ID, meaning that the channel has had its ID finalized.
 func (l *channelLink) EligibleToForward() bool {
 	return l.channel.RemoteNextRevocation() != nil &&
-		l.ShortChanID() != sourceHop
+		l.ShortChanID() != hop.Source
 }
 
 // sampleNetworkFee samples the current fee rate on the network to get into the
@@ -962,7 +962,7 @@ func (l *channelLink) htlcManager() {
 	// only attempt to resolve packages if our short chan id indicates that
 	// the channel is not pending, otherwise we should have no htlcs to
 	// reforward.
-	if l.ShortChanID() != sourceHop {
+	if l.ShortChanID() != hop.Source {
 		if err := l.resolveFwdPkgs(); err != nil {
 			l.fail(LinkFailureError{code: ErrInternalError},
 				"unable to resolve fwd pkgs: %v", err)
@@ -2076,7 +2076,7 @@ func (l *channelLink) UpdateShortChanID() (lnwire.ShortChannelID, error) {
 	if err != nil {
 		l.errorf("unable to refresh short_chan_id for chan_id=%v: %v",
 			chanID, err)
-		return sourceHop, err
+		return hop.Source, err
 	}
 
 	sid := l.channel.ShortChanID()
@@ -2675,7 +2675,7 @@ func (l *channelLink) processRemoteAdds(fwdPkg *channeldb.FwdPkg,
 		}
 
 		switch fwdInfo.NextHop {
-		case exitHop:
+		case hop.Exit:
 			updated, err := l.processExitHop(
 				pd, obfuscator, fwdInfo, heightNow,
 				chanIterator.ExtraOnionBlob(),

htlcswitch/link_test.go

@@ -1937,7 +1937,7 @@ func TestChannelLinkBandwidthConsistency(t *testing.T) {
 	}
 	addPkt := htlcPacket{
 		htlc:           htlc,
-		incomingChanID: sourceHop,
+		incomingChanID: hop.Source,
 		incomingHTLCID: 0,
 		obfuscator:     NewMockObfuscator(),
 	}
@@ -2017,7 +2017,7 @@ func TestChannelLinkBandwidthConsistency(t *testing.T) {
 	}
 	addPkt = htlcPacket{
 		htlc:           htlc,
-		incomingChanID: sourceHop,
+		incomingChanID: hop.Source,
 		incomingHTLCID: 1,
 		obfuscator:     NewMockObfuscator(),
 	}
@@ -2535,7 +2535,7 @@ func genAddsAndCircuits(numHtlcs int, htlc *lnwire.UpdateAddHTLC) (
 	for i := 0; i < numHtlcs; i++ {
 		addPkt := htlcPacket{
 			htlc:           htlc,
-			incomingChanID: sourceHop,
+			incomingChanID: hop.Source,
 			incomingHTLCID: uint64(i),
 			obfuscator:     NewMockObfuscator(),
 		}
@@ -4311,7 +4311,7 @@ func generateHtlcAndInvoice(t *testing.T,
 	hops := []hop.ForwardingInfo{
 		{
 			Network:         hop.BitcoinNetwork,
-			NextHop:         exitHop,
+			NextHop:         hop.Exit,
 			AmountToForward: htlcAmt,
 			OutgoingCTLV:    uint32(htlcExpiry),
 		},

htlcswitch/switch.go

@@ -16,6 +16,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/contractcourt"
+	"github.com/lightningnetwork/lnd/htlcswitch/hop"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -354,7 +355,7 @@ func (s *Switch) GetPaymentResult(paymentID uint64, paymentHash lntypes.Hash,
 		nChan  <-chan *networkResult
 		err    error
 		outKey = CircuitKey{
-			ChanID: sourceHop,
+			ChanID: hop.Source,
 			HtlcID: paymentID,
 		}
 	)
@@ -428,7 +429,7 @@ func (s *Switch) SendHTLC(firstHop lnwire.ShortChannelID, paymentID uint64,
 	// this stage it means that packet haven't left boundaries of our
 	// system and something wrong happened.
 	packet := &htlcPacket{
-		incomingChanID: sourceHop,
+		incomingChanID: hop.Source,
 		incomingHTLCID: paymentID,
 		outgoingChanID: firstHop,
 		htlc:           htlc,
@@ -513,7 +514,7 @@ func (s *Switch) forward(packet *htlcPacket) error {
 			return ErrDuplicateAdd
 
 		case len(actions.Fails) == 1:
-			if packet.incomingChanID == sourceHop {
+			if packet.incomingChanID == hop.Source {
 				return err
 			}
 
@@ -1031,14 +1032,14 @@ func (s *Switch) handlePacketForward(packet *htlcPacket) error {
 	case *lnwire.UpdateAddHTLC:
 		// Check if the node is set to reject all onward HTLCs and also make
 		// sure that HTLC is not from the source node.
-		if s.cfg.RejectHTLC && packet.incomingChanID != sourceHop {
+		if s.cfg.RejectHTLC && packet.incomingChanID != hop.Source {
 			failure := &lnwire.FailChannelDisabled{}
 			addErr := fmt.Errorf("unable to forward any htlcs")
 
 			return s.failAddPacket(packet, failure, addErr)
 		}
 
-		if packet.incomingChanID == sourceHop {
+		if packet.incomingChanID == hop.Source {
 			// A blank incomingChanID indicates that this is
 			// a pending user-initiated payment.
 			return s.handleLocalDispatch(packet)
@@ -1080,7 +1081,7 @@ func (s *Switch) handlePacketForward(packet *htlcPacket) error {
 
 			// If the link doesn't yet have a source chan ID, then
 			// we'll skip it as well.
-			case link.ShortChanID() == sourceHop:
+			case link.ShortChanID() == hop.Source:
 				continue
 			}
 
@@ -1222,7 +1223,7 @@ func (s *Switch) handlePacketForward(packet *htlcPacket) error {
 			//
 			// TODO(roasbeef): only do this once link actually
 			// fully settles?
-			localHTLC := packet.incomingChanID == sourceHop
+			localHTLC := packet.incomingChanID == hop.Source
 			if !localHTLC {
 				s.fwdEventMtx.Lock()
 				s.pendingFwdingEvents = append(
@@ -1241,7 +1242,7 @@ func (s *Switch) handlePacketForward(packet *htlcPacket) error {
 
 		// A blank IncomingChanID in a circuit indicates that it is a pending
 		// user-initiated payment.
-		if packet.incomingChanID == sourceHop {
+		if packet.incomingChanID == hop.Source {
 			return s.handleLocalDispatch(packet)
 		}
 
@@ -1798,7 +1799,7 @@ func (s *Switch) reforwardResponses() error {
 		shortChanID := openChannel.ShortChanID()
 
 		// Locally-initiated payments never need reforwarding.
-		if shortChanID == sourceHop {
+		if shortChanID == hop.Source {
 			continue
 		}
 
@@ -1994,7 +1995,7 @@ func (s *Switch) AddLink(link ChannelLink) error {
 	}
 
 	shortChanID := link.ShortChanID()
-	if shortChanID == sourceHop {
+	if shortChanID == hop.Source {
 		log.Infof("Adding pending link chan_id=%v, short_chan_id=%v",
 			chanID, shortChanID)
 
@@ -2157,7 +2158,7 @@ func (s *Switch) UpdateShortChanID(chanID lnwire.ChannelID) error {
 	}
 
 	// Reject any blank short channel ids.
-	if shortChanID == sourceHop {
+	if shortChanID == hop.Source {
 		return fmt.Errorf("refusing trivial short_chan_id for chan_id=%v"+
 			"live link", chanID)
 	}

htlcswitch/test_utils.go

@@ -648,7 +648,7 @@ func generateHops(payAmt lnwire.MilliSatoshi, startingHeight uint32,
 	for i := len(path) - 1; i >= 0; i-- {
 		// If this is the last hop, then the next hop is the special
 		// "exit node". Otherwise, we look to the "prior" hop.
-		nextHop := exitHop
+		nextHop := hop.Exit
 		if i != len(path)-1 {
 			nextHop = path[i+1].channel.ShortChanID()
 		}