package htlcswitch import ( "bytes" "crypto/sha256" "math/rand" "testing" "time" "io/ioutil" "os" "github.com/btcsuite/fastsha256" "github.com/go-errors/errors" "github.com/lightningnetwork/lnd/channeldb" "github.com/lightningnetwork/lnd/lnwallet" "github.com/lightningnetwork/lnd/lnwire" "github.com/lightningnetwork/lnd/shachain" "github.com/roasbeef/btcd/btcec" "github.com/roasbeef/btcd/chaincfg/chainhash" "github.com/roasbeef/btcd/wire" "github.com/roasbeef/btcutil" ) var ( alicePrivKey = []byte("alice priv key") bobPrivKey = []byte("bob priv key") carolPrivKey = []byte("carol priv key") ) // generateRandomBytes returns securely generated random bytes. // It will return an error if the system's secure random // number generator fails to function correctly, in which // case the caller should not continue. func generateRandomBytes(n int) ([]byte, error) { b := make([]byte, n) _, err := rand.Read(b[:]) // Note that Err == nil only if we read len(b) bytes. if err != nil { return nil, err } return b, nil } // createTestChannel creates the channel and returns our and remote channels // representations. func createTestChannel(alicePrivKey, bobPrivKey []byte, aliceAmount, bobAmount btcutil.Amount, chanID lnwire.ShortChannelID) ( *lnwallet.LightningChannel, *lnwallet.LightningChannel, func(), error) { aliceKeyPriv, aliceKeyPub := btcec.PrivKeyFromBytes(btcec.S256(), alicePrivKey) bobKeyPriv, bobKeyPub := btcec.PrivKeyFromBytes(btcec.S256(), bobPrivKey) channelCapacity := aliceAmount + bobAmount aliceDustLimit := btcutil.Amount(200) bobDustLimit := btcutil.Amount(800) csvTimeoutAlice := uint32(5) csvTimeoutBob := uint32(4) witnessScript, _, err := lnwallet.GenFundingPkScript( aliceKeyPub.SerializeCompressed(), bobKeyPub.SerializeCompressed(), int64(channelCapacity), ) if err != nil { return nil, nil, nil, err } var hash [sha256.Size]byte randomSeed, err := generateRandomBytes(sha256.Size) if err != nil { return nil, nil, nil, err } copy(hash[:], randomSeed) prevOut := &wire.OutPoint{ Hash: chainhash.Hash(hash), Index: 0, } fundingTxIn := wire.NewTxIn(prevOut, nil, nil) bobRoot := lnwallet.DeriveRevocationRoot(bobKeyPriv, bobKeyPub, aliceKeyPub) bobPreimageProducer := shachain.NewRevocationProducer(*bobRoot) bobFirstRevoke, err := bobPreimageProducer.AtIndex(0) if err != nil { return nil, nil, nil, err } bobRevokeKey := lnwallet.DeriveRevocationPubkey(aliceKeyPub, bobFirstRevoke[:]) aliceRoot := lnwallet.DeriveRevocationRoot(aliceKeyPriv, aliceKeyPub, bobKeyPub) alicePreimageProducer := shachain.NewRevocationProducer(*aliceRoot) aliceFirstRevoke, err := alicePreimageProducer.AtIndex(0) if err != nil { return nil, nil, nil, err } aliceRevokeKey := lnwallet.DeriveRevocationPubkey(bobKeyPub, aliceFirstRevoke[:]) aliceCommitTx, err := lnwallet.CreateCommitTx( fundingTxIn, aliceKeyPub, bobKeyPub, aliceRevokeKey, csvTimeoutAlice, aliceAmount, bobAmount, lnwallet.DefaultDustLimit(), ) if err != nil { return nil, nil, nil, err } bobCommitTx, err := lnwallet.CreateCommitTx( fundingTxIn, bobKeyPub, aliceKeyPub, bobRevokeKey, csvTimeoutBob, bobAmount, aliceAmount, lnwallet.DefaultDustLimit(), ) if err != nil { return nil, nil, nil, err } alicePath, err := ioutil.TempDir("", "alicedb") dbAlice, err := channeldb.Open(alicePath) if err != nil { return nil, nil, nil, err } bobPath, err := ioutil.TempDir("", "bobdb") dbBob, err := channeldb.Open(bobPath) if err != nil { return nil, nil, nil, err } var obsfucator [lnwallet.StateHintSize]byte copy(obsfucator[:], aliceFirstRevoke[:]) aliceChannelState := &channeldb.OpenChannel{ IdentityPub: aliceKeyPub, ChanID: prevOut, ChanType: channeldb.SingleFunder, IsInitiator: true, StateHintObsfucator: obsfucator, OurCommitKey: aliceKeyPub, TheirCommitKey: bobKeyPub, Capacity: channelCapacity, OurBalance: aliceAmount, TheirBalance: bobAmount, OurCommitTx: aliceCommitTx, OurCommitSig: bytes.Repeat([]byte{1}, 71), FundingOutpoint: prevOut, OurMultiSigKey: aliceKeyPub, TheirMultiSigKey: bobKeyPub, FundingWitnessScript: witnessScript, LocalCsvDelay: csvTimeoutAlice, RemoteCsvDelay: csvTimeoutBob, TheirCurrentRevocation: bobRevokeKey, RevocationProducer: alicePreimageProducer, RevocationStore: shachain.NewRevocationStore(), TheirDustLimit: bobDustLimit, OurDustLimit: aliceDustLimit, ShortChanID: chanID, Db: dbAlice, } bobChannelState := &channeldb.OpenChannel{ IdentityPub: bobKeyPub, ChanID: prevOut, ChanType: channeldb.SingleFunder, IsInitiator: false, StateHintObsfucator: obsfucator, OurCommitKey: bobKeyPub, TheirCommitKey: aliceKeyPub, Capacity: channelCapacity, OurBalance: bobAmount, TheirBalance: aliceAmount, OurCommitTx: bobCommitTx, OurCommitSig: bytes.Repeat([]byte{1}, 71), FundingOutpoint: prevOut, OurMultiSigKey: bobKeyPub, TheirMultiSigKey: aliceKeyPub, FundingWitnessScript: witnessScript, LocalCsvDelay: csvTimeoutBob, RemoteCsvDelay: csvTimeoutAlice, TheirCurrentRevocation: aliceRevokeKey, RevocationProducer: bobPreimageProducer, RevocationStore: shachain.NewRevocationStore(), TheirDustLimit: aliceDustLimit, OurDustLimit: bobDustLimit, ShortChanID: chanID, Db: dbBob, } cleanUpFunc := func() { os.RemoveAll(bobPath) os.RemoveAll(alicePath) } aliceSigner := &mockSigner{aliceKeyPriv} bobSigner := &mockSigner{bobKeyPriv} estimator := &lnwallet.StaticFeeEstimator{ FeeRate: 24, Confirmation: 6, } channelAlice, err := lnwallet.NewLightningChannel(aliceSigner, nil, estimator, aliceChannelState) if err != nil { return nil, nil, nil, err } channelBob, err := lnwallet.NewLightningChannel(bobSigner, nil, estimator, bobChannelState) if err != nil { return nil, nil, nil, err } return channelAlice, channelBob, cleanUpFunc, nil } // getChanID retrieves the channel point from nwire message. func getChanID(msg lnwire.Message) lnwire.ChannelID { var point lnwire.ChannelID switch msg := msg.(type) { case *lnwire.UpdateAddHTLC: point = msg.ChanID case *lnwire.UpdateFufillHTLC: point = msg.ChanID case *lnwire.UpdateFailHTLC: point = msg.ChanID case *lnwire.RevokeAndAck: point = msg.ChanID case *lnwire.CommitSig: point = msg.ChanID } return point } // generatePayment generates the htlc add request by given path blob and // invoice which should be added by destination peer. func generatePayment(invoiceAmt, htlcAmt btcutil.Amount, timelock uint32, blob [lnwire.OnionPacketSize]byte) (*channeldb.Invoice, *lnwire.UpdateAddHTLC, error) { // Initialize random seed with unix time in order to generate random // preimage every time. rand.Seed(time.Now().UTC().UnixNano()) var preimage [sha256.Size]byte r, err := generateRandomBytes(sha256.Size) if err != nil { return nil, nil, err } copy(preimage[:], r) rhash := fastsha256.Sum256(preimage[:]) invoice := &channeldb.Invoice{ CreationDate: time.Now(), Terms: channeldb.ContractTerm{ Value: invoiceAmt, PaymentPreimage: preimage, }, } htlc := &lnwire.UpdateAddHTLC{ PaymentHash: rhash, Amount: htlcAmt, Expiry: timelock, OnionBlob: blob, } return invoice, htlc, nil } // generateRoute generates the path blob by given array of peers. func generateRoute(hops ...ForwardingInfo) ([lnwire.OnionPacketSize]byte, error) { var blob [lnwire.OnionPacketSize]byte if len(hops) == 0 { return blob, errors.New("empty path") } iterator := newMockHopIterator(hops...) w := bytes.NewBuffer(blob[0:0]) if err := iterator.EncodeNextHop(w); err != nil { return blob, err } return blob, nil } // threeHopNetwork is used for managing the created cluster of 3 hops. type threeHopNetwork struct { aliceServer *mockServer aliceChannelLink *channelLink firstBobChannelLink *channelLink bobServer *mockServer secondBobChannelLink *channelLink carolChannelLink *channelLink carolServer *mockServer firstChannelCleanup func() secondChannelCleanup func() globalPolicy ForwardingPolicy } // generateHops creates the per hop payload, the total amount to be sent, and // also the time lock value needed to route a HTLC with the target amount over // the specified path. func generateHops(payAmt btcutil.Amount, path ...*channelLink) (btcutil.Amount, uint32, []ForwardingInfo) { lastHop := path[len(path)-1] var ( totalTimelock uint32 ) runningAmt := payAmt hops := make([]ForwardingInfo, len(path)) 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 if i != len(path)-1 { nextHop = path[i+1].channel.ShortChanID() } // If this is the last, hop, then the time lock will be their // specified delta policy. timeLock := lastHop.cfg.FwrdingPolicy.TimeLockDelta totalTimelock += timeLock // Otherwise, the outgoing time lock should be the incoming // timelock minus their specified delta. if i != len(path)-1 { delta := path[i].cfg.FwrdingPolicy.TimeLockDelta timeLock = totalTimelock - delta } // Finally, we'll need to calculate the amount to forward. For // the last hop, it's just the payment amount. amount := payAmt if i != len(path)-1 { prevHop := hops[i+1] prevAmount := prevHop.AmountToForward fee := ExpectedFee(path[i].cfg.FwrdingPolicy, prevAmount) runningAmt += fee // If the this the first hop, then we don't need to // apply any fee, otherwise, the amount to forward // needs to take into account the fees. if i == 0 { amount = prevAmount } else { amount = prevAmount + fee } } hops[i] = ForwardingInfo{ Network: BitcoinHop, NextHop: nextHop, AmountToForward: amount, OutgoingCTLV: timeLock, } } return runningAmt, totalTimelock, hops } // makePayment takes the destination node and amount as input, sends the // payment and returns the error channel to wait for error to be received and // invoice in order to check its status after the payment finished. // // With this function you can send payments: // * from Alice to Bob // * from Alice to Carol through the Bob // * from Alice to some another peer through the Bob func (n *threeHopNetwork) makePayment(sendingPeer, receivingPeer Peer, firstHopPub [33]byte, hops []ForwardingInfo, invoiceAmt, htlcAmt btcutil.Amount, timelock uint32) (*channeldb.Invoice, error) { sender := sendingPeer.(*mockServer) receiver := receivingPeer.(*mockServer) // Generate route convert it to blob, and return next destination for // htlc add request. blob, err := generateRoute(hops...) if err != nil { return nil, err } // Generate payment: invoice and htlc. invoice, htlc, err := generatePayment(invoiceAmt, htlcAmt, timelock, blob) if err != nil { return nil, err } // Check who is last in the route and add invoice to server registry. if err := receiver.registry.AddInvoice(invoice); err != nil { return nil, err } // Send payment and expose err channel. errChan := make(chan error) go func() { _, err := sender.htlcSwitch.SendHTLC(firstHopPub, htlc) errChan <- err }() select { case err := <-errChan: return invoice, err case <-time.After(50 * time.Second): return invoice, errors.New("htlc was not settled in time") } } // start starts the three hop network alice,bob,carol servers. func (n *threeHopNetwork) start() error { if err := n.aliceServer.Start(); err != nil { return err } if err := n.bobServer.Start(); err != nil { return err } if err := n.carolServer.Start(); err != nil { return err } return nil } // stop stops nodes and cleanup its databases. func (n *threeHopNetwork) stop() { done := make(chan struct{}) go func() { n.aliceServer.Stop() done <- struct{}{} }() go func() { n.bobServer.Stop() done <- struct{}{} }() go func() { n.carolServer.Stop() done <- struct{}{} }() for i := 0; i < 3; i++ { <-done } n.firstChannelCleanup() n.secondChannelCleanup() } // newThreeHopNetwork function creates the following topology and returns the // control object to manage this cluster: // // alice bob carol // server - <-connection-> - server - - <-connection-> - - - server // | | | // alice htlc bob htlc carol htlc // switch switch \ switch // | | \ | // | | \ | // alice first bob second bob carol // channel link channel link channel link channel link // func newThreeHopNetwork(t *testing.T, aliceToBob, bobToCarol btcutil.Amount) *threeHopNetwork { var err error // Create three peers/servers. aliceServer := newMockServer(t, "alice") bobServer := newMockServer(t, "bob") carolServer := newMockServer(t, "carol") // Create mock decoder instead of sphinx one in order to mock the // route which htlc should follow. decoder := &mockIteratorDecoder{} firstChanID := lnwire.NewShortChanIDFromInt(4) secondChanID := lnwire.NewShortChanIDFromInt(5) // Create lightning channels between Alice<->Bob and Bob<->Carol aliceChannel, firstBobChannel, fCleanUp, err := createTestChannel( alicePrivKey, bobPrivKey, aliceToBob, aliceToBob, firstChanID) if err != nil { t.Fatalf("unable to create alice<->bob channel: %v", err) } secondBobChannel, carolChannel, sCleanUp, err := createTestChannel( bobPrivKey, carolPrivKey, bobToCarol, bobToCarol, secondChanID) if err != nil { t.Fatalf("unable to create bob<->carol channel: %v", err) } globalPolicy := ForwardingPolicy{ MinHTLC: 5, BaseFee: btcutil.Amount(1), TimeLockDelta: 1, } aliceChannelLink := NewChannelLink( ChannelLinkConfig{ FwrdingPolicy: globalPolicy, Peer: bobServer, Switch: aliceServer.htlcSwitch, DecodeOnion: decoder.Decode, Registry: aliceServer.registry, }, aliceChannel, ) if err := aliceServer.htlcSwitch.addLink(aliceChannelLink); err != nil { t.Fatalf("unable to add alice channel link: %v", err) } firstBobChannelLink := NewChannelLink( ChannelLinkConfig{ FwrdingPolicy: globalPolicy, Peer: aliceServer, Switch: bobServer.htlcSwitch, DecodeOnion: decoder.Decode, Registry: bobServer.registry, }, firstBobChannel, ) if err := bobServer.htlcSwitch.addLink(firstBobChannelLink); err != nil { t.Fatalf("unable to add first bob channel link: %v", err) } secondBobChannelLink := NewChannelLink( ChannelLinkConfig{ FwrdingPolicy: globalPolicy, Peer: carolServer, Switch: bobServer.htlcSwitch, DecodeOnion: decoder.Decode, Registry: bobServer.registry, }, secondBobChannel, ) if err := bobServer.htlcSwitch.addLink(secondBobChannelLink); err != nil { t.Fatalf("unable to add second bob channel link: %v", err) } carolChannelLink := NewChannelLink( ChannelLinkConfig{ FwrdingPolicy: globalPolicy, Peer: bobServer, Switch: carolServer.htlcSwitch, DecodeOnion: decoder.Decode, Registry: carolServer.registry, }, carolChannel, ) if err := carolServer.htlcSwitch.addLink(carolChannelLink); err != nil { t.Fatalf("unable to add carol channel link: %v", err) } return &threeHopNetwork{ aliceServer: aliceServer, aliceChannelLink: aliceChannelLink.(*channelLink), firstBobChannelLink: firstBobChannelLink.(*channelLink), bobServer: bobServer, secondBobChannelLink: secondBobChannelLink.(*channelLink), carolChannelLink: carolChannelLink.(*channelLink), carolServer: carolServer, firstChannelCleanup: fCleanUp, secondChannelCleanup: sCleanUp, globalPolicy: globalPolicy, } }