lnd: hook up encrypted onion error scaffolding

In this commit daemon have been changed to set the proper hooks in the
channel link and switch subsystems so that they could send and receive
encrypted onion errors.

peer.go

@@ -20,6 +20,7 @@ import (
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/lightningnetwork/lnd/routing"
 	"github.com/roasbeef/btcd/btcec"
 	"github.com/roasbeef/btcd/chaincfg/chainhash"
 	"github.com/roasbeef/btcd/connmgr"
@@ -306,11 +307,13 @@ func (p *peer) loadActiveChannels(chans []*channeldb.OpenChannel) error {
 		// Register this new channel link with the HTLC Switch. This is
 		// necessary to properly route multi-hop payments, and forward
 		// new payments triggered by RPC clients.
-		sphinxDecoder := htlcswitch.NewSphinxDecoder(p.server.sphinx)
 		link := htlcswitch.NewChannelLink(
 			htlcswitch.ChannelLinkConfig{
-				Peer:             p,
-				DecodeOnion:      sphinxDecoder.Decode,
+				Peer:                  p,
+				DecodeHopIterator:     p.server.sphinx.DecodeHopIterator,
+				DecodeOnionObfuscator: p.server.sphinx.DecodeOnionObfuscator,
+				GetLastChannelUpdate: createGetLastUpdate(p.server.chanRouter,
+					p.PubKey(), lnChan.ShortChanID()),
 				SettledContracts: p.server.breachArbiter.settledContracts,
 				DebugHTLC:        cfg.DebugHTLC,
 				Registry:         p.server.invoices,
@@ -786,11 +789,13 @@ out:
 			peerLog.Infof("New channel active ChannelPoint(%v) "+
 				"with peerId(%v)", chanPoint, p.id)
 
-			decoder := htlcswitch.NewSphinxDecoder(p.server.sphinx)
 			link := htlcswitch.NewChannelLink(
 				htlcswitch.ChannelLinkConfig{
-					Peer:             p,
-					DecodeOnion:      decoder.Decode,
+					Peer:                  p,
+					DecodeHopIterator:     p.server.sphinx.DecodeHopIterator,
+					DecodeOnionObfuscator: p.server.sphinx.DecodeOnionObfuscator,
+					GetLastChannelUpdate: createGetLastUpdate(p.server.chanRouter,
+						p.PubKey(), newChanReq.channel.ShortChanID()),
 					SettledContracts: p.server.breachArbiter.settledContracts,
 					DebugHTLC:        cfg.DebugHTLC,
 					Registry:         p.server.invoices,
@@ -1365,3 +1370,41 @@ func (p *peer) PubKey() [33]byte {
 }
 
 // TODO(roasbeef): make all start/stop mutexes a CAS
+
+// createGetLastUpdate returns the handler which serve as a source of the last
+// update of the channel in a form of lnwire update message.
+func createGetLastUpdate(router *routing.ChannelRouter,
+	pubKey [33]byte, chanID lnwire.ShortChannelID) func() (*lnwire.ChannelUpdate,
+	error) {
+
+	return func() (*lnwire.ChannelUpdate, error) {
+		_, edge1, edge2, err := router.GetChannelByID(chanID)
+		if err != nil {
+			return nil, err
+		}
+
+		if edge1 == nil || edge2 == nil {
+			return nil, errors.Errorf("unable to find "+
+				"channel by ShortChannelID(%v)", chanID)
+		}
+
+		var local *channeldb.ChannelEdgePolicy
+		if bytes.Compare(edge1.Node.PubKey.SerializeCompressed(),
+			pubKey[:]) == 0 {
+			local = edge2
+		} else {
+			local = edge1
+		}
+
+		return &lnwire.ChannelUpdate{
+			Signature:       local.Signature,
+			ShortChannelID:  lnwire.NewShortChanIDFromInt(local.ChannelID),
+			Timestamp:       uint32(time.Now().Unix()),
+			Flags:           local.Flags,
+			TimeLockDelta:   local.TimeLockDelta,
+			HtlcMinimumMsat: uint64(local.MinHTLC),
+			BaseFee:         uint32(local.FeeBaseMSat),
+			FeeRate:         uint32(local.FeeProportionalMillionths),
+		}, nil
+	}
+}

server.go

@@ -71,7 +71,7 @@ type server struct {
 
 	utxoNursery *utxoNursery
 
-	sphinx *sphinx.Router
+	sphinx *htlcswitch.OnionProcessor
 
 	connMgr *connmgr.ConnManager
 
@@ -126,7 +126,8 @@ func newServer(listenAddrs []string, chanDB *channeldb.DB, cc *chainControl,
 
 		// TODO(roasbeef): derive proper onion key based on rotation
 		// schedule
-		sphinx:      sphinx.NewRouter(privKey, activeNetParams.Params),
+		sphinx: htlcswitch.NewOnionProcessor(
+			sphinx.NewRouter(privKey, activeNetParams.Params)),
 		lightningID: sha256.Sum256(serializedPubKey),
 
 		persistentPeers:    make(map[string]struct{}),
@@ -236,11 +237,19 @@ func newServer(listenAddrs []string, chanDB *channeldb.DB, cc *chainControl,
 		Chain:     cc.chainIO,
 		ChainView: cc.chainView,
 		SendToSwitch: func(firstHop *btcec.PublicKey,
-			htlcAdd *lnwire.UpdateAddHTLC) ([32]byte, error) {
+			htlcAdd *lnwire.UpdateAddHTLC,
+			circuit *sphinx.Circuit) ([32]byte, error) {
+
+			// Initialize the data obfuscator in order to be able to decode the
+			// onion failure and wrap it so that we could process lnwire onion
+			// failures.
+			failureDeobfuscator := &htlcswitch.FailureDeobfuscator{
+				OnionDeobfuscator: sphinx.NewOnionDeobfuscator(circuit),
+			}
 
 			var firstHopPub [33]byte
 			copy(firstHopPub[:], firstHop.SerializeCompressed())
-			return s.htlcSwitch.SendHTLC(firstHopPub, htlcAdd)
+			return s.htlcSwitch.SendHTLC(firstHopPub, htlcAdd, failureDeobfuscator)
 		},
 	})
 	if err != nil {