package main import ( "bytes" "encoding/binary" "fmt" "sync" "sync/atomic" "time" "golang.org/x/crypto/salsa20" "github.com/boltdb/bolt" "github.com/davecgh/go-spew/spew" "github.com/go-errors/errors" "github.com/lightningnetwork/lnd/chainntnfs" "github.com/lightningnetwork/lnd/channeldb" "github.com/lightningnetwork/lnd/htlcswitch" "github.com/lightningnetwork/lnd/lnrpc" "github.com/lightningnetwork/lnd/lnwallet" "github.com/lightningnetwork/lnd/lnwire" "github.com/roasbeef/btcd/btcec" "github.com/roasbeef/btcd/chaincfg/chainhash" "github.com/roasbeef/btcd/wire" "github.com/roasbeef/btcutil" "google.golang.org/grpc" ) const ( // TODO(roasbeef): tune msgBufferSize = 50 defaultCsvDelay = 4 // maxFundingAmount is a soft-limit of the maximum channel size // accepted within the Lightning Protocol Currently. This limit is // currently defined in BOLT-0002, and serves as an initial // precaturioary limit while implementations are battle tested in the // real world. // // TODO(roasbeef): add command line param to modify maxFundingAmount = btcutil.Amount(1 << 24) // maxWaitNumBlocksFundingConf is the maximum number of blocks to wait // for the funding transaction to be confirmed before forgetting about // the channel. 288 blocks is ~48 hrs maxWaitNumBlocksFundingConf = 288 ) // reservationWithCtx encapsulates a pending channel reservation. This wrapper // struct is used internally within the funding manager to track and progress // the funding workflow initiated by incoming/outgoing methods from the target // peer. Additionally, this struct houses a response and error channel which is // used to respond to the caller in the case a channel workflow is initiated // via a local signal such as RPC. // // TODO(roasbeef): actually use the context package // * deadlines, etc. type reservationWithCtx struct { reservation *lnwallet.ChannelReservation peerAddress *lnwire.NetAddress chanAmt btcutil.Amount updates chan *lnrpc.OpenStatusUpdate err chan error } // initFundingMsg is sent by an outside subsystem to the funding manager in // order to kick off a funding workflow with a specified target peer. The // original request which defines the parameters of the funding workflow are // embedded within this message giving the funding manager full context w.r.t // the workflow. type initFundingMsg struct { peerAddress *lnwire.NetAddress *openChanReq } // fundingOpenMsg couples an lnwire.OpenChannel message with the peer who sent // the message. This allows the funding manager to queue a response directly to // the peer, progressing the funding workflow. type fundingOpenMsg struct { msg *lnwire.OpenChannel peerAddress *lnwire.NetAddress } // fundingAcceptMsg couples an lnwire.AcceptChannel message with the peer who // sent the message. This allows the funding manager to queue a response // directly to the peer, progressing the funding workflow. type fundingAcceptMsg struct { msg *lnwire.AcceptChannel peerAddress *lnwire.NetAddress } // fundingCreatedMsg couples an lnwire.FundingCreated message with the peer who // sent the message. This allows the funding manager to queue a response // directly to the peer, progressing the funding workflow. type fundingCreatedMsg struct { msg *lnwire.FundingCreated peerAddress *lnwire.NetAddress } // fundingSignedMsg couples an lnwire.FundingSigned message with the peer who // sent the message. This allows the funding manager to queue a response // directly to the peer, progressing the funding workflow. type fundingSignedMsg struct { msg *lnwire.FundingSigned peerAddress *lnwire.NetAddress } // fundingLockedMsg couples an lnwire.FundingLocked message with the peer who // sent the message. This allows the funding manager to finalize the funding // process and announce the existence of the new channel. type fundingLockedMsg struct { msg *lnwire.FundingLocked peerAddress *lnwire.NetAddress } // fundingErrorMsg couples an lnwire.Error message with the peer who sent the // message. This allows the funding manager to properly process the error. type fundingErrorMsg struct { err *lnwire.Error peerAddress *lnwire.NetAddress } // pendingChannels is a map instantiated per-peer which tracks all active // pending single funded channels indexed by their pending channel identifier, // which is a set of 32-bytes generated via a CSPRNG. type pendingChannels map[[32]byte]*reservationWithCtx // serializedPubKey is used within the FundingManager's activeReservations list // to identify the nodes with which the FundingManager is actively working to // initiate new channels. type serializedPubKey [33]byte // newSerializedKey creates a new serialized public key from an instance of a // live pubkey object. func newSerializedKey(pubKey *btcec.PublicKey) serializedPubKey { var s serializedPubKey copy(s[:], pubKey.SerializeCompressed()) return s } // fundingConfig defines the configuration for the FundingManager. All elements // within the configuration MUST be non-nil for the FundingManager to carry out // its duties. type fundingConfig struct { // IDKey is the PublicKey that is used to identify this node within the // Lightning Network. IDKey *btcec.PublicKey // Wallet handles the parts of the funding process that involves moving // funds from on-chain transaction outputs into Lightning channels. Wallet *lnwallet.LightningWallet // FeeEstimator calculates appropriate fee rates based on historical // transaction information. FeeEstimator lnwallet.FeeEstimator // ArbiterChan allows the FundingManager to notify the BreachArbiter // that a new channel has been created that should be observed to // ensure that the channel counterparty hasn't broadcast an invalid // commitment transaction. ArbiterChan chan<- *lnwallet.LightningChannel // Notifier is used by the FundingManager to determine when the // channel's funding transaction has been confirmed on the blockchain // so that the channel creation process can be completed. Notifier chainntnfs.ChainNotifier // SignMessage signs an arbitrary method with a given public key. The // actual digest signed is the double sha-256 of the message. In the // case that the private key corresponding to the passed public key // cannot be located, then an error is returned. // // TODO(roasbeef): should instead pass on this responsibility to a // distinct sub-system? SignMessage func(pubKey *btcec.PublicKey, msg []byte) (*btcec.Signature, error) // CurrentNodeAnnouncement should return the latest, fully signed node // announcement from the backing Lighting Network node. CurrentNodeAnnouncement func() (lnwire.NodeAnnouncement, error) // SendAnnouncement is used by the FundingManager to announce newly // created channels to the rest of the Lightning Network. SendAnnouncement func(msg lnwire.Message) error // SendToPeer allows the FundingManager to send messages to the peer // node during the multiple steps involved in the creation of the // channel's funding transaction and initial commitment transaction. SendToPeer func(target *btcec.PublicKey, msgs ...lnwire.Message) error // FindPeer searches the list of peers connected to the node so that // the FundingManager can notify other daemon subsystems as necessary // during the funding process. FindPeer func(peerKey *btcec.PublicKey) (*peer, error) // FindChannel queries the database for the channel with the given // channel ID. FindChannel func(chanID lnwire.ChannelID) (*lnwallet.LightningChannel, error) // TempChanIDSeed is a cryptographically random string of bytes that's // used as a seed to generate pending channel ID's. TempChanIDSeed [32]byte // DefaultRoutingPolicy is the default routing policy used when // initially announcing channels. DefaultRoutingPolicy htlcswitch.ForwardingPolicy // 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 // the amount of the channel, and any funds we'll be pushed in the // process to determine how many confirmations we'll require. NumRequiredConfs func(btcutil.Amount, lnwire.MilliSatoshi) uint16 // RequiredRemoteDelay is a function that maps the total amount in a // proposed channel to the CSV delay that we'll require for the remote // party. Naturally a larger channel should require a higher CSV delay // in order to give us more time to claim funds in the case of a // contract breach. RequiredRemoteDelay func(btcutil.Amount) uint16 } // fundingManager acts as an orchestrator/bridge between the wallet's // 'ChannelReservation' workflow, and the wire protocol's funding initiation // messages. Any requests to initiate the funding workflow for a channel, // either kicked-off locally or remotely handled by the funding manager. // Once a channel's funding workflow has been completed, any local callers, the // local peer, and possibly the remote peer are notified of the completion of // the channel workflow. Additionally, any temporary or permanent access // controls between the wallet and remote peers are enforced via the funding // manager. type fundingManager struct { // MUST be used atomically. started int32 stopped int32 // cfg is a copy of the configuration struct that the FundingManager was // initialized with. cfg *fundingConfig // chanIDKey is a cryptographically random key that's used to generate // temporary channel ID's. chanIDKey [32]byte // chanIDNonce is a nonce that's incremented for each new funding // reservation created. nonceMtx sync.RWMutex chanIDNonce uint64 // activeReservations is a map which houses the state of all pending // funding workflows. activeReservations map[serializedPubKey]pendingChannels // signedReservations is a utility map that maps the permanent channel // ID of a funding reservation to its temporary channel ID. This is // required as mid funding flow, we switch to referencing the channel // by its full channel ID once the commitment transactions have been // signed by both parties. signedReservations map[lnwire.ChannelID][32]byte // resMtx guards both of the maps above to ensure that all access is // goroutine stafe. resMtx sync.RWMutex // fundingMsgs is a channel which receives wrapped wire messages // related to funding workflow from outside peers. fundingMsgs chan interface{} // queries is a channel which receives requests to query the internal // state of the funding manager. queries chan interface{} // fundingRequests is a channel used to receive channel initiation // requests from a local subsystem within the daemon. fundingRequests chan *initFundingMsg // newChanBarriers is a map from a channel ID to a 'barrier' which will // be signalled once the channel is fully open. This barrier acts as a // synchronization point for any incoming/outgoing HTLCs before the // channel has been fully opened. barrierMtx sync.RWMutex newChanBarriers map[lnwire.ChannelID]chan struct{} localDiscoveryMtx sync.Mutex localDiscoverySignals map[lnwire.ChannelID]chan struct{} quit chan struct{} wg sync.WaitGroup } // channelOpeningState represents the different states a channel can be in // between the funding transaction has been confirmed and the channel is // announced to the network and ready to be used. type channelOpeningState uint8 const ( // markedOpen is the opening state of a channel if the funding // transaction is confirmed on-chain, but fundingLocked is not yet // successfully sent to the other peer. markedOpen channelOpeningState = iota // fundingLockedSent is the opening state of a channel if the // fundingLocked message has successfully been sent to the other peer, // but we still haven't announced the channel to the network. fundingLockedSent ) var ( // channelOpeningStateBucket is the database bucket used to store the // channelOpeningState for each channel that is currently in the process // of being opened. channelOpeningStateBucket = []byte("channelOpeningState") // ErrChannelNotFound is returned when we are looking for a specific // channel opening state in the FundingManager's internal database, but // the channel in question is not considered being in an opening state. ErrChannelNotFound = fmt.Errorf("channel not found in db") ) // newFundingManager creates and initializes a new instance of the // fundingManager. func newFundingManager(cfg fundingConfig) (*fundingManager, error) { return &fundingManager{ cfg: &cfg, chanIDKey: cfg.TempChanIDSeed, activeReservations: make(map[serializedPubKey]pendingChannels), signedReservations: make(map[lnwire.ChannelID][32]byte), newChanBarriers: make(map[lnwire.ChannelID]chan struct{}), fundingMsgs: make(chan interface{}, msgBufferSize), fundingRequests: make(chan *initFundingMsg, msgBufferSize), localDiscoverySignals: make(map[lnwire.ChannelID]chan struct{}), queries: make(chan interface{}, 1), quit: make(chan struct{}), }, nil } // Start launches all helper goroutines required for handling requests sent // to the funding manager. func (f *fundingManager) Start() error { if atomic.AddInt32(&f.started, 1) != 1 { // TODO(roasbeef): CAS instead return nil } fndgLog.Tracef("Funding manager running") // Upon restart, the Funding Manager will check the database to load any // channels that were waiting for their funding transactions to be // confirmed on the blockchain at the time when the daemon last went // down. // TODO(roasbeef): store height that funding finished? // * would then replace call below pendingChannels, err := f.cfg.Wallet.Cfg.Database.FetchPendingChannels() if err != nil { return err } // For any channels that were in a pending state when the daemon was // last connected, the Funding Manager will re-initialize the channel // barriers and will also launch waitForFundingConfirmation to wait for // the channel's funding transaction to be confirmed on the blockchain. for _, channel := range pendingChannels { f.barrierMtx.Lock() fndgLog.Tracef("Loading pending ChannelPoint(%v), creating chan "+ "barrier", channel.FundingOutpoint) chanID := lnwire.NewChanIDFromOutPoint(&channel.FundingOutpoint) f.newChanBarriers[chanID] = make(chan struct{}) f.barrierMtx.Unlock() f.localDiscoverySignals[chanID] = make(chan struct{}) doneChan := make(chan struct{}) timeoutChan := make(chan struct{}) go func(ch *channeldb.OpenChannel) { go f.waitForFundingWithTimeout(ch, doneChan, timeoutChan) select { case <-timeoutChan: // Timeout waiting for the funding transaction // to confirm, so we forget the channel and // delete it from the database. closeInfo := &channeldb.ChannelCloseSummary{ ChanPoint: ch.FundingOutpoint, RemotePub: ch.IdentityPub, CloseType: channeldb.FundingCanceled, } if err := ch.CloseChannel(closeInfo); err != nil { fndgLog.Errorf("Failed closing channel "+ "%v: %v", ch.FundingOutpoint, err) } case <-f.quit: // The fundingManager is shutting down, and will // resume wait on startup. case <-doneChan: // Success, funding transaction was confirmed. } }(channel) } // Fetch all our open channels, and make sure they all finalized the // opening process. // TODO(halseth): this check is only done on restart atm, but should // also be done if a peer that disappeared during the opening process // reconnects. openChannels, err := f.cfg.Wallet.Cfg.Database.FetchAllChannels() if err != nil { return err } for _, channel := range openChannels { channelState, shortChanID, err := f.getChannelOpeningState( &channel.FundingOutpoint) if err == ErrChannelNotFound { // Channel not in fundingManager's opening database, // meaning it was successully announced to the network. continue } else if err != nil { return err } fndgLog.Debugf("channel with opening state %v found", channelState) chanID := lnwire.NewChanIDFromOutPoint(&channel.FundingOutpoint) f.localDiscoverySignals[chanID] = make(chan struct{}) // If we did find the channel in the opening state database, we // have seen the funding transaction being confirmed, but we // did not finish the rest of the setup procedure before we shut // down. We handle the remaining steps of this setup by // continuing the procedure where we left off. switch channelState { case markedOpen: // The funding transaction was confirmed, but we did not // successfully send the fundingLocked message to the // peer, so let's do that now. f.wg.Add(1) go func() { defer f.wg.Done() f.sendFundingLockedAndAnnounceChannel(channel, shortChanID) }() case fundingLockedSent: // fundingLocked was sent to peer, but the channel // announcement was not sent. f.wg.Add(1) go func() { defer f.wg.Done() lnChannel, err := lnwallet.NewLightningChannel( nil, nil, f.cfg.FeeEstimator, channel) if err != nil { fndgLog.Errorf("error creating "+ "lightning channel: %v", err) } defer lnChannel.Stop() f.sendChannelAnnouncement(channel, lnChannel, shortChanID) }() default: fndgLog.Errorf("undefined channelState: %v", channelState) } } f.wg.Add(1) // TODO(roasbeef): tune go f.reservationCoordinator() return nil } // Stop signals all helper goroutines to execute a graceful shutdown. This // method will block until all goroutines have exited. func (f *fundingManager) Stop() error { if atomic.AddInt32(&f.stopped, 1) != 1 { return nil } fndgLog.Infof("Funding manager shutting down") close(f.quit) f.wg.Wait() return nil } // nextPendingChanID returns the next free pending channel ID to be used to // identify a particular future channel funding workflow. func (f *fundingManager) nextPendingChanID() [32]byte { // Obtain a fresh nonce. We do this by encoding the current nonce // counter, then incrementing it by one. f.nonceMtx.Lock() var nonce [8]byte binary.LittleEndian.PutUint64(nonce[:], f.chanIDNonce) f.chanIDNonce++ f.nonceMtx.Unlock() // We'll generate the next pending channelID by "encrypting" 32-bytes // of zeroes which'll extract 32 random bytes from our stream cipher. var ( nextChanID [32]byte zeroes [32]byte ) salsa20.XORKeyStream(nextChanID[:], zeroes[:], nonce[:], &f.chanIDKey) return nextChanID } type pendingChannel struct { identityPub *btcec.PublicKey channelPoint *wire.OutPoint capacity btcutil.Amount localBalance btcutil.Amount remoteBalance btcutil.Amount } type pendingChansReq struct { resp chan []*pendingChannel err chan error } // PendingChannels returns a slice describing all the channels which are // currently pending at the last state of the funding workflow. func (f *fundingManager) PendingChannels() ([]*pendingChannel, error) { respChan := make(chan []*pendingChannel, 1) errChan := make(chan error) req := &pendingChansReq{ resp: respChan, err: errChan, } f.queries <- req return <-respChan, <-errChan } // failFundingFlow will fail the active funding flow with the target peer, // identified by it's unique temporary channel ID. This method is send an error // to the remote peer, and also remove the reservation from our set of pending // reservations. // // TODO(roasbeef): if peer disconnects, and haven't yet broadcast funding // transaction, then all reservations should be cleared. func (f *fundingManager) failFundingFlow(peer *btcec.PublicKey, tempChanID [32]byte, msg []byte) { errMsg := &lnwire.Error{ ChanID: tempChanID, Data: msg, } fndgLog.Errorf("Failing funding flow: %v", spew.Sdump(errMsg)) err := f.cfg.SendToPeer(peer, errMsg) if err != nil { fndgLog.Errorf("unable to send error message to peer %v", err) return } f.cancelReservationCtx(peer, tempChanID) return } // reservationCoordinator is the primary goroutine tasked with progressing the // funding workflow between the wallet, and any outside peers or local callers. // // NOTE: This MUST be run as a goroutine. func (f *fundingManager) reservationCoordinator() { defer f.wg.Done() for { select { case msg := <-f.fundingMsgs: switch fmsg := msg.(type) { case *fundingOpenMsg: f.handleFundingOpen(fmsg) case *fundingAcceptMsg: f.handleFundingAccept(fmsg) case *fundingCreatedMsg: f.handleFundingCreated(fmsg) case *fundingSignedMsg: f.handleFundingSigned(fmsg) case *fundingLockedMsg: go f.handleFundingLocked(fmsg) case *fundingErrorMsg: f.handleErrorMsg(fmsg) } case req := <-f.fundingRequests: f.handleInitFundingMsg(req) case req := <-f.queries: switch msg := req.(type) { case *pendingChansReq: f.handlePendingChannels(msg) } case <-f.quit: return } } } // handlePendingChannels responds to a request for details concerning all // currently pending channels waiting for the final phase of the funding // workflow (funding txn confirmation). func (f *fundingManager) handlePendingChannels(msg *pendingChansReq) { var pendingChannels []*pendingChannel dbPendingChannels, err := f.cfg.Wallet.Cfg.Database.FetchPendingChannels() if err != nil { msg.resp <- nil msg.err <- err return } for _, dbPendingChan := range dbPendingChannels { pendingChan := &pendingChannel{ identityPub: dbPendingChan.IdentityPub, channelPoint: &dbPendingChan.FundingOutpoint, capacity: dbPendingChan.Capacity, localBalance: dbPendingChan.LocalBalance.ToSatoshis(), remoteBalance: dbPendingChan.RemoteBalance.ToSatoshis(), } pendingChannels = append(pendingChannels, pendingChan) } msg.resp <- pendingChannels msg.err <- nil } // processFundingOpen sends a message to the fundingManager allowing it to // initiate the new funding workflow with the source peer. func (f *fundingManager) processFundingOpen(msg *lnwire.OpenChannel, peerAddress *lnwire.NetAddress) { f.fundingMsgs <- &fundingOpenMsg{msg, peerAddress} } // handleFundingOpen creates an initial 'ChannelReservation' within the wallet, // then responds to the source peer with an accept channel message progressing // the funding workflow. // // TODO(roasbeef): add error chan to all, let channelManager handle // error+propagate func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) { // Check number of pending channels to be smaller than maximum allowed // number and send ErrorGeneric to remote peer if condition is // violated. peerIDKey := newSerializedKey(fmsg.peerAddress.IdentityKey) msg := fmsg.msg amt := msg.FundingAmount // TODO(roasbeef): modify to only accept a _single_ pending channel per // block unless white listed if len(f.activeReservations[peerIDKey]) >= cfg.MaxPendingChannels { f.failFundingFlow( fmsg.peerAddress.IdentityKey, fmsg.msg.PendingChannelID, lnwire.ErrorData{byte(lnwire.ErrMaxPendingChannels)}, ) return } // We'll also reject any requests to create channels until we're fully // synced to the network as we won't be able to properly validate the // confirmation of the funding transaction. isSynced, err := f.cfg.Wallet.IsSynced() if err != nil { fndgLog.Errorf("unable to query wallet: %v", err) return } if !isSynced { f.failFundingFlow( fmsg.peerAddress.IdentityKey, fmsg.msg.PendingChannelID, lnwire.ErrorData{byte(lnwire.ErrSynchronizingChain)}, ) return } // We'll reject any request to create a channel that's above the // current soft-limit for channel size. if msg.FundingAmount > maxFundingAmount { f.failFundingFlow( fmsg.peerAddress.IdentityKey, fmsg.msg.PendingChannelID, lnwire.ErrorData{byte(lnwire.ErrChanTooLarge)}, ) return } // TODO(roasbeef): error if funding flow already ongoing fndgLog.Infof("Recv'd fundingRequest(amt=%v, push=%v, delay=%v, "+ "pendingId=%x) from peer(%x)", amt, msg.PushAmount, msg.CsvDelay, msg.PendingChannelID, fmsg.peerAddress.IdentityKey.SerializeCompressed()) // Attempt to initialize a reservation within the wallet. If the wallet // has insufficient resources to create the channel, then the // reservation attempt may be rejected. Note that since we're on the // responding side of a single funder workflow, we don't commit any // funds to the channel ourselves. // // TODO(roasbeef): assuming this was an inbound connection, replace // port with default advertised port chainHash := chainhash.Hash(msg.ChainHash) reservation, err := f.cfg.Wallet.InitChannelReservation(amt, 0, msg.PushAmount, btcutil.Amount(msg.FeePerKiloWeight), fmsg.peerAddress.IdentityKey, fmsg.peerAddress.Address, &chainHash) if err != nil { fndgLog.Errorf("Unable to initialize reservation: %v", err) f.failFundingFlow(fmsg.peerAddress.IdentityKey, msg.PendingChannelID, []byte(err.Error())) return } // As we're the responder, we get to specify the number of // confirmations that we require before both of us consider the channel // open. We'll use out mapping to derive the proper number of // confirmations based on the amount of the channel, and also if any // funds are being pushed to us. numConfsReq := f.cfg.NumRequiredConfs(msg.FundingAmount, msg.PushAmount) reservation.SetNumConfsRequired(numConfsReq) // We'll also validate and apply all the constraints the initiating // party is attempting to dictate for our commitment transaction. err = reservation.CommitConstraints( uint16(msg.CsvDelay), msg.MaxAcceptedHTLCs, msg.MaxValueInFlight, msg.ChannelReserve, ) if err != nil { f.failFundingFlow( fmsg.peerAddress.IdentityKey, fmsg.msg.PendingChannelID, []byte(fmt.Sprintf("Unacceptable channel "+ "constraints: %v", err)), ) return } fndgLog.Infof("Requiring %v confirmations for pendingChan(%x): "+ "amt=%v, push_amt=%v", numConfsReq, fmsg.msg.PendingChannelID, amt, msg.PushAmount) // Once the reservation has been created successfully, we add it to // this peers map of pending reservations to track this particular // reservation until either abort or completion. f.resMtx.Lock() if _, ok := f.activeReservations[peerIDKey]; !ok { f.activeReservations[peerIDKey] = make(pendingChannels) } f.activeReservations[peerIDKey][msg.PendingChannelID] = &reservationWithCtx{ reservation: reservation, chanAmt: amt, err: make(chan error, 1), peerAddress: fmsg.peerAddress, } f.resMtx.Unlock() // Using the RequiredRemoteDelay closure, we'll compute the remote CSV // delay we require given the total amount of funds within the channel. remoteCsvDelay := f.cfg.RequiredRemoteDelay(amt) // We'll also generate our required constraints for the remote party, chanReserve, maxValue, maxHtlcs := reservation.RemoteChanConstraints() // With our parameters set, we'll now process their contribution so we // can move the funding workflow ahead. remoteContribution := &lnwallet.ChannelContribution{ FundingAmount: amt, FirstCommitmentPoint: msg.FirstCommitmentPoint, ChannelConfig: &channeldb.ChannelConfig{ ChannelConstraints: channeldb.ChannelConstraints{ DustLimit: msg.DustLimit, MaxPendingAmount: maxValue, ChanReserve: chanReserve, MinHTLC: msg.HtlcMinimum, MaxAcceptedHtlcs: maxHtlcs, }, CsvDelay: remoteCsvDelay, MultiSigKey: copyPubKey(msg.FundingKey), RevocationBasePoint: copyPubKey(msg.RevocationPoint), PaymentBasePoint: copyPubKey(msg.PaymentPoint), DelayBasePoint: copyPubKey(msg.DelayedPaymentPoint), }, } err = reservation.ProcessSingleContribution(remoteContribution) if err != nil { fndgLog.Errorf("unable to add contribution reservation: %v", err) // TODO(roasbeef): verify only sending sane info over f.failFundingFlow(fmsg.peerAddress.IdentityKey, msg.PendingChannelID, []byte(err.Error())) return } fndgLog.Infof("Sending fundingResp for pendingID(%x)", msg.PendingChannelID) fndgLog.Debugf("Remote party accepted commitment constraints: %v", spew.Sdump(remoteContribution.ChannelConfig.ChannelConstraints)) // With the initiator's contribution recorded, respond with our // contribution in the next message of the workflow. ourContribution := reservation.OurContribution() fundingAccept := lnwire.AcceptChannel{ PendingChannelID: msg.PendingChannelID, DustLimit: ourContribution.DustLimit, MaxValueInFlight: maxValue, ChannelReserve: chanReserve, MinAcceptDepth: uint32(numConfsReq), HtlcMinimum: ourContribution.MinHTLC, CsvDelay: uint16(remoteCsvDelay), MaxAcceptedHTLCs: maxHtlcs, FundingKey: ourContribution.MultiSigKey, RevocationPoint: ourContribution.RevocationBasePoint, PaymentPoint: ourContribution.PaymentBasePoint, DelayedPaymentPoint: ourContribution.DelayBasePoint, FirstCommitmentPoint: ourContribution.FirstCommitmentPoint, } err = f.cfg.SendToPeer(fmsg.peerAddress.IdentityKey, &fundingAccept) if err != nil { fndgLog.Errorf("unable to send funding response to peer: %v", err) f.failFundingFlow(fmsg.peerAddress.IdentityKey, msg.PendingChannelID, []byte(err.Error())) return } } // processFundingAccept sends a message to the fundingManager allowing it to // continue the second phase of a funding workflow with the target peer. func (f *fundingManager) processFundingAccept(msg *lnwire.AcceptChannel, peerAddress *lnwire.NetAddress) { f.fundingMsgs <- &fundingAcceptMsg{msg, peerAddress} } // handleFundingAceept processes a response to the workflow initiation sent by // the remote peer. This message then queues a message with the funding // outpoint, and a commitment signature to the remote peer. func (f *fundingManager) handleFundingAccept(fmsg *fundingAcceptMsg) { msg := fmsg.msg pendingChanID := fmsg.msg.PendingChannelID peerKey := fmsg.peerAddress.IdentityKey resCtx, err := f.getReservationCtx(peerKey, pendingChanID) if err != nil { fndgLog.Warnf("Can't find reservation (peerKey:%v, chanID:%v)", peerKey, pendingChanID) return } fndgLog.Infof("Recv'd fundingResponse for pendingID(%x)", pendingChanID[:]) // We'll also specify the responder's preference for the number of // required confirmations, and also the set of channel constraints // they've specified for commitment states we can create. resCtx.reservation.SetNumConfsRequired(uint16(msg.MinAcceptDepth)) err = resCtx.reservation.CommitConstraints( uint16(msg.CsvDelay), msg.MaxAcceptedHTLCs, msg.MaxValueInFlight, msg.ChannelReserve, ) if err != nil { f.failFundingFlow( fmsg.peerAddress.IdentityKey, fmsg.msg.PendingChannelID, []byte(fmt.Sprintf("Unacceptable channel "+ "constraints: %v", err)), ) return } // As they've accepted our channel constraints, we'll regenerate them // here so we can properly commit their accepted constraints to the // reservation. chanReserve, maxValue, maxHtlcs := resCtx.reservation.RemoteChanConstraints() // The remote node has responded with their portion of the channel // contribution. At this point, we can process their contribution which // allows us to construct and sign both the commitment transaction, and // the funding transaction. remoteContribution := &lnwallet.ChannelContribution{ FirstCommitmentPoint: msg.FirstCommitmentPoint, ChannelConfig: &channeldb.ChannelConfig{ ChannelConstraints: channeldb.ChannelConstraints{ DustLimit: msg.DustLimit, MaxPendingAmount: maxValue, ChanReserve: chanReserve, MinHTLC: msg.HtlcMinimum, MaxAcceptedHtlcs: maxHtlcs, }, MultiSigKey: copyPubKey(msg.FundingKey), RevocationBasePoint: copyPubKey(msg.RevocationPoint), PaymentBasePoint: copyPubKey(msg.PaymentPoint), DelayBasePoint: copyPubKey(msg.DelayedPaymentPoint), }, } remoteContribution.CsvDelay = f.cfg.RequiredRemoteDelay(resCtx.chanAmt) err = resCtx.reservation.ProcessContribution(remoteContribution) if err != nil { fndgLog.Errorf("Unable to process contribution from %v: %v", fmsg.peerAddress.IdentityKey, err) f.failFundingFlow(fmsg.peerAddress.IdentityKey, msg.PendingChannelID, []byte(err.Error())) resCtx.err <- err return } fndgLog.Infof("pendingChan(%x): remote party proposes num_confs=%v, "+ "csv_delay=%v", pendingChanID[:], msg.MinAcceptDepth, msg.CsvDelay) fndgLog.Debugf("Remote party accepted commitment constraints: %v", spew.Sdump(remoteContribution.ChannelConfig.ChannelConstraints)) // Now that we have their contribution, we can extract, then send over // both the funding out point and our signature for their version of // the commitment transaction to the remote peer. outPoint := resCtx.reservation.FundingOutpoint() _, sig := resCtx.reservation.OurSignatures() commitSig, err := btcec.ParseSignature(sig, btcec.S256()) if err != nil { fndgLog.Errorf("Unable to parse signature: %v", err) f.failFundingFlow(fmsg.peerAddress.IdentityKey, msg.PendingChannelID, []byte(err.Error())) resCtx.err <- err return } // A new channel has almost finished the funding process. In order to // properly synchronize with the writeHandler goroutine, we add a new // channel to the barriers map which will be closed once the channel is // fully open. f.barrierMtx.Lock() channelID := lnwire.NewChanIDFromOutPoint(outPoint) fndgLog.Debugf("Creating chan barrier for ChanID(%v)", channelID) f.newChanBarriers[channelID] = make(chan struct{}) f.barrierMtx.Unlock() // The next message that advances the funding flow will reference the // channel via its permanent channel ID, so we'll set up this mapping // so we can retrieve the reservation context once we get the // FundingSigned message. f.resMtx.Lock() f.signedReservations[channelID] = pendingChanID f.resMtx.Unlock() fndgLog.Infof("Generated ChannelPoint(%v) for pendingID(%x)", outPoint, pendingChanID[:]) fundingCreated := &lnwire.FundingCreated{ PendingChannelID: pendingChanID, FundingPoint: *outPoint, CommitSig: commitSig, } err = f.cfg.SendToPeer(fmsg.peerAddress.IdentityKey, fundingCreated) if err != nil { fndgLog.Errorf("Unable to send funding complete message: %v", err) f.failFundingFlow(fmsg.peerAddress.IdentityKey, msg.PendingChannelID, []byte(err.Error())) resCtx.err <- err return } } // processFundingCreated queues a funding complete message coupled with the // source peer to the fundingManager. func (f *fundingManager) processFundingCreated(msg *lnwire.FundingCreated, peerAddress *lnwire.NetAddress) { f.fundingMsgs <- &fundingCreatedMsg{msg, peerAddress} } // handleFundingCreated progresses the funding workflow when the daemon is on // the responding side of a single funder workflow. Once this message has been // processed, a signature is sent to the remote peer allowing it to broadcast // the funding transaction, progressing the workflow into the final stage. func (f *fundingManager) handleFundingCreated(fmsg *fundingCreatedMsg) { peerKey := fmsg.peerAddress.IdentityKey pendingChanID := fmsg.msg.PendingChannelID resCtx, err := f.getReservationCtx(peerKey, pendingChanID) if err != nil { fndgLog.Warnf("can't find reservation (peerID:%v, chanID:%x)", peerKey, pendingChanID[:]) return } // The channel initiator has responded with the funding outpoint of the // final funding transaction, as well as a signature for our version of // the commitment transaction. So at this point, we can validate the // initiator's commitment transaction, then send our own if it's valid. // TODO(roasbeef): make case (p vs P) consistent throughout fundingOut := fmsg.msg.FundingPoint fndgLog.Infof("completing pendingID(%x) with ChannelPoint(%v)", pendingChanID[:], fundingOut) // With all the necessary data available, attempt to advance the // funding workflow to the next stage. If this succeeds then the // funding transaction will broadcast after our next message. // CompleteReservationSingle will also mark the channel as 'IsPending' // in the database. commitSig := fmsg.msg.CommitSig.Serialize() completeChan, err := resCtx.reservation.CompleteReservationSingle( &fundingOut, commitSig) if err != nil { // TODO(roasbeef): better error logging: peerID, channelID, etc. fndgLog.Errorf("unable to complete single reservation: %v", err) f.failFundingFlow(fmsg.peerAddress.IdentityKey, pendingChanID, []byte(err.Error())) return } // If something goes wrong before the funding transaction is confirmed, // we use this convenience method to delete the pending OpenChannel // from the database. deleteFromDatabase := func() { closeInfo := &channeldb.ChannelCloseSummary{ ChanPoint: completeChan.FundingOutpoint, RemotePub: completeChan.IdentityPub, CloseType: channeldb.FundingCanceled, } if err := completeChan.CloseChannel(closeInfo); err != nil { fndgLog.Errorf("Failed closing channel %v: %v", completeChan.FundingOutpoint, err) } } // A new channel has almost finished the funding process. In order to // properly synchronize with the writeHandler goroutine, we add a new // channel to the barriers map which will be closed once the channel is // fully open. f.barrierMtx.Lock() channelID := lnwire.NewChanIDFromOutPoint(&fundingOut) fndgLog.Debugf("Creating chan barrier for ChanID(%v)", channelID) f.newChanBarriers[channelID] = make(chan struct{}) f.barrierMtx.Unlock() fndgLog.Infof("sending signComplete for pendingID(%x) over ChannelPoint(%v)", pendingChanID[:], fundingOut) // With their signature for our version of the commitment transaction // verified, we can now send over our signature to the remote peer. // // TODO(roasbeef): just have raw bytes in wire msg? avoids decoding // then decoding shortly afterwards. _, sig := resCtx.reservation.OurSignatures() ourCommitSig, err := btcec.ParseSignature(sig, btcec.S256()) if err != nil { fndgLog.Errorf("unable to parse signature: %v", err) f.failFundingFlow(fmsg.peerAddress.IdentityKey, pendingChanID, []byte(err.Error())) deleteFromDatabase() return } fundingSigned := &lnwire.FundingSigned{ ChanID: channelID, CommitSig: ourCommitSig, } if err := f.cfg.SendToPeer(peerKey, fundingSigned); err != nil { fndgLog.Errorf("unable to send FundingSigned message: %v", err) f.failFundingFlow(fmsg.peerAddress.IdentityKey, pendingChanID, []byte(err.Error())) deleteFromDatabase() return } // Create an entry in the local discovery map so we can ensure that we // process the channel confirmation fully before we receive a funding // locked message. f.localDiscoveryMtx.Lock() f.localDiscoverySignals[channelID] = make(chan struct{}) f.localDiscoveryMtx.Unlock() // With this last message, our job as the responder is now complete. // We'll wait for the funding transaction to reach the specified number // of confirmations, then start normal operations. // // When we get to this point we have sent the signComplete message to // the channel funder, and BOLT#2 specifies that we MUST remember the // channel for reconnection. The channel is already marked // as pending in the database, so in case of a disconnect or restart, // we will continue waiting for the confirmation the next time we start // the funding manager. In case the funding transaction never appears // on the blockchain, we must forget this channel. We therefore // completely forget about this channel if we haven't seen the funding // transaction in 288 blocks (~ 48 hrs), by canceling the reservation // and canceling the wait for the funding confirmation. go func() { doneChan := make(chan struct{}) timeoutChan := make(chan struct{}) go f.waitForFundingWithTimeout(completeChan, doneChan, timeoutChan) select { case <-timeoutChan: // We did not see the funding confirmation before // timeout, so we forget the channel. deleteFromDatabase() case <-f.quit: // The fundingManager is shutting down, will resume // wait for funding transaction on startup. case <-doneChan: // Success, funding transaction was confirmed. f.deleteReservationCtx(peerKey, fmsg.msg.PendingChannelID) } }() } // processFundingSigned sends a single funding sign complete message along with // the source peer to the funding manager. func (f *fundingManager) processFundingSigned(msg *lnwire.FundingSigned, peerAddress *lnwire.NetAddress) { f.fundingMsgs <- &fundingSignedMsg{msg, peerAddress} } // handleFundingSigned processes the final message received in a single funder // workflow. Once this message is processed, the funding transaction is // broadcast. Once the funding transaction reaches a sufficient number of // confirmations, a message is sent to the responding peer along with a compact // encoding of the location of the channel within the blockchain. func (f *fundingManager) handleFundingSigned(fmsg *fundingSignedMsg) { // As the funding signed message will reference the reservation by it's // permanent channel ID, we'll need to perform an intermediate look up // before we can obtain the reservation. f.resMtx.Lock() pendingChanID, ok := f.signedReservations[fmsg.msg.ChanID] delete(f.signedReservations, fmsg.msg.ChanID) f.resMtx.Unlock() if !ok { err := fmt.Sprintf("Unable to find signed reservation for "+ "chan_id=%x", fmsg.msg.ChanID) fndgLog.Warnf(err) f.failFundingFlow(fmsg.peerAddress.IdentityKey, pendingChanID, []byte(err)) return } peerKey := fmsg.peerAddress.IdentityKey resCtx, err := f.getReservationCtx(fmsg.peerAddress.IdentityKey, pendingChanID) if err != nil { fndgLog.Warnf("Unable to find reservation (peerID:%v, chanID:%x)", peerKey, pendingChanID[:]) f.failFundingFlow(fmsg.peerAddress.IdentityKey, pendingChanID, []byte(err.Error())) return } // Create an entry in the local discovery map so we can ensure that we // process the channel confirmation fully before we receive a funding // locked message. fundingPoint := resCtx.reservation.FundingOutpoint() permChanID := lnwire.NewChanIDFromOutPoint(fundingPoint) f.localDiscoveryMtx.Lock() f.localDiscoverySignals[permChanID] = make(chan struct{}) f.localDiscoveryMtx.Unlock() // The remote peer has responded with a signature for our commitment // transaction. We'll verify the signature for validity, then commit // the state to disk as we can now open the channel. commitSig := fmsg.msg.CommitSig.Serialize() completeChan, err := resCtx.reservation.CompleteReservation(nil, commitSig) if err != nil { fndgLog.Errorf("Unable to complete reservation sign complete: %v", err) resCtx.err <- err f.failFundingFlow(fmsg.peerAddress.IdentityKey, pendingChanID, []byte(err.Error())) return } fndgLog.Infof("Finalizing pendingID(%x) over ChannelPoint(%v), "+ "waiting for channel open on-chain", pendingChanID[:], fundingPoint) // Send an update to the upstream client that the negotiation process // is over. // TODO(roasbeef): add abstraction over updates to accommodate // long-polling, or SSE, etc. resCtx.updates <- &lnrpc.OpenStatusUpdate{ Update: &lnrpc.OpenStatusUpdate_ChanPending{ ChanPending: &lnrpc.PendingUpdate{ Txid: fundingPoint.Hash[:], OutputIndex: fundingPoint.Index, }, }, } go func() { doneChan := make(chan struct{}) cancelChan := make(chan struct{}) // In case the fundingManager is stopped at some point during // the remaining part of the opening process, we must wait for // this process to finish (either successully or with some // error), before the fundingManager can be shut down. f.wg.Add(1) go func() { defer f.wg.Done() f.waitForFundingConfirmation(completeChan, cancelChan, doneChan) }() select { case <-f.quit: return case <-doneChan: } // Finally give the caller a final update notifying them that // the channel is now open. // TODO(roasbeef): only notify after recv of funding locked? resCtx.updates <- &lnrpc.OpenStatusUpdate{ Update: &lnrpc.OpenStatusUpdate_ChanOpen{ ChanOpen: &lnrpc.ChannelOpenUpdate{ ChannelPoint: &lnrpc.ChannelPoint{ FundingTxid: fundingPoint.Hash[:], OutputIndex: fundingPoint.Index, }, }, }, } f.deleteReservationCtx(peerKey, pendingChanID) }() } // waitForFundingWithTimeout is a wrapper around waitForFundingConfirmation that // will cancel the wait for confirmation if maxWaitNumBlocksFundingConf has // passed from bestHeight. In the case of timeout, the timeoutChan will be // closed. In case of confirmation or error, doneChan will be closed. func (f *fundingManager) waitForFundingWithTimeout(completeChan *channeldb.OpenChannel, doneChan chan<- struct{}, timeoutChan chan<- struct{}) { epochClient, err := f.cfg.Notifier.RegisterBlockEpochNtfn() if err != nil { fndgLog.Errorf("unable to register for epoch notification: %v", err) close(doneChan) return } defer epochClient.Cancel() waitingDoneChan := make(chan struct{}) cancelChan := make(chan struct{}) // Add this goroutine to wait group so we can be sure that it is // properly stopped before the funding manager can be shut down. f.wg.Add(1) go func() { defer f.wg.Done() f.waitForFundingConfirmation(completeChan, cancelChan, waitingDoneChan) }() // On block maxHeight we will cancel the funding confirmation wait. maxHeight := completeChan.FundingBroadcastHeight + maxWaitNumBlocksFundingConf for { select { case epoch, ok := <-epochClient.Epochs: if !ok { fndgLog.Warnf("Epoch client shutting down") return } if uint32(epoch.Height) >= maxHeight { fndgLog.Warnf("waited for %v blocks without "+ "seeing funding transaction confirmed,"+ " cancelling.", maxWaitNumBlocksFundingConf) // Cancel the waitForFundingConfirmation // goroutine. close(cancelChan) // Notify the caller of the timeout. close(timeoutChan) return } case <-f.quit: // The fundingManager is shutting down, will resume // waiting for the funding transaction on startup. return case <-waitingDoneChan: close(doneChan) return } } } // waitForFundingConfirmation handles the final stages of the channel funding // process once the funding transaction has been broadcast. The primary // function of waitForFundingConfirmation is to wait for blockchain // confirmation, and then to notify the other systems that must be notified // when a channel has become active for lightning transactions. // The wait can be canceled by closing the cancelChan. func (f *fundingManager) waitForFundingConfirmation(completeChan *channeldb.OpenChannel, cancelChan <-chan struct{}, doneChan chan<- struct{}) { defer close(doneChan) // Register with the ChainNotifier for a notification once the funding // transaction reaches `numConfs` confirmations. txid := completeChan.FundingOutpoint.Hash numConfs := uint32(completeChan.NumConfsRequired) confNtfn, err := f.cfg.Notifier.RegisterConfirmationsNtfn(&txid, numConfs, completeChan.FundingBroadcastHeight) if err != nil { fndgLog.Errorf("Unable to register for confirmation of "+ "ChannelPoint(%v)", completeChan.FundingOutpoint) return } fndgLog.Infof("Waiting for funding tx (%v) to reach %v confirmations", txid, numConfs) var confDetails *chainntnfs.TxConfirmation var ok bool // Wait until the specified number of confirmations has been reached, // we get a cancel signal, or the wallet signals a shutdown. select { case confDetails, ok = <-confNtfn.Confirmed: // fallthrough case <-cancelChan: fndgLog.Warnf("canceled waiting for funding confirmation, "+ "stopping funding flow for ChannelPoint(%v)", completeChan.FundingOutpoint) return case <-f.quit: fndgLog.Warnf("fundingManager shutting down, stopping funding "+ "flow for ChannelPoint(%v)", completeChan.FundingOutpoint) return } if !ok { fndgLog.Warnf("ChainNotifier shutting down, cannot complete "+ "funding flow for ChannelPoint(%v)", completeChan.FundingOutpoint) return } fundingPoint := completeChan.FundingOutpoint chanID := lnwire.NewChanIDFromOutPoint(&fundingPoint) fndgLog.Infof("ChannelPoint(%v) is now active: ChannelID(%x)", fundingPoint, chanID[:]) // With the block height and the transaction index known, we can // construct the compact chanID which is used on the network to unique // identify channels. shortChanID := lnwire.ShortChannelID{ BlockHeight: confDetails.BlockHeight, TxIndex: confDetails.TxIndex, TxPosition: uint16(fundingPoint.Index), } // Now that the channel has been fully confirmed, we'll mark it as open // within the database. completeChan.IsPending = false err = f.cfg.Wallet.Cfg.Database.MarkChannelAsOpen(&fundingPoint, shortChanID) if err != nil { fndgLog.Errorf("error setting channel pending flag to false: "+ "%v", err) return } // TODO(roasbeef): ideally persistent state update for chan above // should be abstracted // The funding transaction now being confirmed, we add this channel to // the fundingManager's internal persistant state machine that we use // to track the remaining process of the channel opening. This is useful // to resume the opening process in case of restarts. // // TODO(halseth): make the two db transactions (MarkChannelAsOpen and // saveChannelOpeningState) atomic by doing them in the same transaction. // Needed to be properly fault-tolerant. err = f.saveChannelOpeningState(&completeChan.FundingOutpoint, markedOpen, &shortChanID) if err != nil { fndgLog.Errorf("error setting channel state to markedOpen: %v", err) return } // Now that the funding transaction has the required number of // confirmations, we send the fundingLocked message to the peer. f.sendFundingLockedAndAnnounceChannel(completeChan, &shortChanID) } // sendFundingLockedAndAnnounceChannel creates and sends the fundingLocked // message, and then the channel announcement. This should be called after the // funding transaction has been confirmed, and the channelState is 'markedOpen'. func (f *fundingManager) sendFundingLockedAndAnnounceChannel( completeChan *channeldb.OpenChannel, shortChanID *lnwire.ShortChannelID) { chanID := lnwire.NewChanIDFromOutPoint(&completeChan.FundingOutpoint) // With the channel marked open, we'll create the state-machine object // which wraps the database state. channel, err := lnwallet.NewLightningChannel(nil, nil, f.cfg.FeeEstimator, completeChan) if err != nil { fndgLog.Errorf("error creating new lightning channel: %v", err) return } defer channel.Stop() // Next, we'll send over the funding locked message which marks that we // consider the channel open by presenting the remote party with our // next revocation key. Without the revocation key, the remote party // will be unable to propose state transitions. nextRevocation, err := channel.NextRevocationKey() if err != nil { fndgLog.Errorf("unable to create next revocation: %v", err) return } fundingLockedMsg := lnwire.NewFundingLocked(chanID, nextRevocation) err = f.cfg.SendToPeer(completeChan.IdentityPub, fundingLockedMsg) if err != nil { fndgLog.Errorf("unable to send fundingLocked to peer: %v", err) return } // As the fundingLocked message is now sent to the peer, the channel is // moved to the next state of the state machine. It will be moved to the // last state (actually deleted from the database) after the channel is // finally announced. err = f.saveChannelOpeningState(&completeChan.FundingOutpoint, fundingLockedSent, shortChanID) if err != nil { fndgLog.Errorf("error setting channel state to "+ "fundingLockedSent: %v", err) return } // TODO(roasbeef): wait 6 blocks before announcing f.sendChannelAnnouncement(completeChan, channel, shortChanID) } // sendChannelAnnouncement broadcast the necessary channel announcement // messages to the network. Should be called after the fundingLocked message // is sent (channelState is 'fundingLockedSent') and the channel is ready to // be used. func (f *fundingManager) sendChannelAnnouncement(completeChan *channeldb.OpenChannel, channel *lnwallet.LightningChannel, shortChanID *lnwire.ShortChannelID) { chanID := lnwire.NewChanIDFromOutPoint(&completeChan.FundingOutpoint) fundingPoint := completeChan.FundingOutpoint fndgLog.Infof("Announcing ChannelPoint(%v), short_chan_id=%v", &fundingPoint, spew.Sdump(shortChanID)) // Register the new link with the L3 routing manager so this new // channel can be utilized during path finding. err := f.announceChannel(f.cfg.IDKey, completeChan.IdentityPub, channel.LocalFundingKey, channel.RemoteFundingKey, *shortChanID, chanID) if err != nil { fndgLog.Errorf("channel announcement failed: %v", err) return } // After the channel is successfully announced from the // fundingManager, we delete the channel from our internal database. // We can do this // because we assume the AuthenticatedGossiper queues the announcement // messages, and persists them in case of a daemon shutdown. err = f.deleteChannelOpeningState(&completeChan.FundingOutpoint) if err != nil { fndgLog.Errorf("error deleting channel state: %v", err) return } // Finally, as the local channel discovery has been fully processed, // we'll trigger the signal indicating that it's safe for any funding // locked messages related to this channel to be processed. f.localDiscoveryMtx.Lock() if discoverySignal, ok := f.localDiscoverySignals[chanID]; ok { close(discoverySignal) } f.localDiscoveryMtx.Unlock() return } // processFundingLocked sends a message to the fundingManager allowing it to // finish the funding workflow. func (f *fundingManager) processFundingLocked(msg *lnwire.FundingLocked, peerAddress *lnwire.NetAddress) { f.fundingMsgs <- &fundingLockedMsg{msg, peerAddress} } // handleFundingLocked finalizes the channel funding process and enables the // channel to enter normal operating mode. func (f *fundingManager) handleFundingLocked(fmsg *fundingLockedMsg) { f.localDiscoveryMtx.Lock() localDiscoverySignal, ok := f.localDiscoverySignals[fmsg.msg.ChanID] f.localDiscoveryMtx.Unlock() if ok { // Before we proceed with processing the funding locked // message, we'll wait for the lcoal waitForFundingConfirmation // goroutine to signal that it has the necessary state in // place. Otherwise, we may be missing critical information // required to handle forwarded HTLC's. <-localDiscoverySignal // With the signal received, we can now safely delete the entry // from the map. f.localDiscoveryMtx.Lock() delete(f.localDiscoverySignals, fmsg.msg.ChanID) f.localDiscoveryMtx.Unlock() } // First, we'll attempt to locate the channel who's funding workflow is // being finalized by this message. We got to the database rather than // our reservation map as we may have restarted, mid funding flow. chanID := fmsg.msg.ChanID channel, err := f.cfg.FindChannel(chanID) if err != nil { fndgLog.Errorf("Unable to locate ChannelID(%v), cannot complete "+ "funding", chanID) return } // TODO(roasbeef): done nothing if repeat message sent // The funding locked message contains the next commitment point we'll // need to create the next commitment state for the remote party. So // we'll insert that into the channel now before passing it along to // other sub-systems. err = channel.InitNextRevocation(fmsg.msg.NextPerCommitmentPoint) if err != nil { fndgLog.Errorf("unable to insert next commitment point: %v", err) return } // With the channel retrieved, we'll send the breach arbiter the new // channel so it can watch for attempts to breach the channel's // contract by the remote party. f.cfg.ArbiterChan <- channel // Launch a defer so we _ensure_ that the channel barrier is properly // closed even if the target peer is not longer online at this point. defer func() { // Close the active channel barrier signalling the readHandler // that commitment related modifications to this channel can // now proceed. f.barrierMtx.Lock() fndgLog.Tracef("Closing chan barrier for ChanID(%v)", chanID) close(f.newChanBarriers[chanID]) delete(f.newChanBarriers, chanID) f.barrierMtx.Unlock() }() // Finally, we'll find the peer that sent us this message so we can // provide it with the fully initialized channel state. peer, err := f.cfg.FindPeer(fmsg.peerAddress.IdentityKey) if err != nil { fndgLog.Errorf("Unable to find peer: %v", err) return } newChanDone := make(chan struct{}) newChanMsg := &newChannelMsg{ channel: channel, done: newChanDone, } peer.newChannels <- newChanMsg // We pause here to wait for the peer to recognize the new channel // before we close the channel barrier corresponding to the channel. select { case <-f.quit: return case <-newChanDone: // Fallthrough if we're not quitting. } } // channelProof is one half of the proof necessary to create an authenticated // announcement on the network. The two signatures individually sign a // statement of the existence of a channel. type channelProof struct { nodeSig *btcec.Signature bitcoinSig *btcec.Signature } // chanAnnouncement encapsulates the two authenticated announcements that we // send out to the network after a new channel has been created locally. type chanAnnouncement struct { chanAnn *lnwire.ChannelAnnouncement chanUpdateAnn *lnwire.ChannelUpdate chanProof *lnwire.AnnounceSignatures } // newChanAnnouncement creates the authenticated channel announcement messages // required to broadcast a newly created channel to the network. The // announcement is two part: the first part authenticates the existence of the // channel and contains four signatures binding the funding pub keys and // identity pub keys of both parties to the channel, and the second segment is // authenticated only by us and contains our directional routing policy for the // channel. func (f *fundingManager) newChanAnnouncement(localPubKey, remotePubKey *btcec.PublicKey, localFundingKey, remoteFundingKey *btcec.PublicKey, shortChanID lnwire.ShortChannelID, chanID lnwire.ChannelID) (*chanAnnouncement, error) { chainHash := *f.cfg.Wallet.Cfg.NetParams.GenesisHash // The unconditional section of the announcement is the ShortChannelID // itself which compactly encodes the location of the funding output // within the blockchain. chanAnn := &lnwire.ChannelAnnouncement{ ShortChannelID: shortChanID, Features: lnwire.NewFeatureVector([]lnwire.Feature{}), ChainHash: chainHash, } // The chanFlags field indicates which directed edge of the channel is // being updated within the ChannelUpdateAnnouncement announcement // below. A value of zero means it's the edge of the "first" node and 1 // being the other node. var chanFlags uint16 // The lexicographical ordering of the two identity public keys of the // nodes indicates which of the nodes is "first". If our serialized // identity key is lower than theirs then we're the "first" node and // second otherwise. selfBytes := localPubKey.SerializeCompressed() remoteBytes := remotePubKey.SerializeCompressed() if bytes.Compare(selfBytes, remoteBytes) == -1 { chanAnn.NodeID1 = localPubKey chanAnn.NodeID2 = remotePubKey chanAnn.BitcoinKey1 = localFundingKey chanAnn.BitcoinKey2 = remoteFundingKey // If we're the first node then update the chanFlags to // indicate the "direction" of the update. chanFlags = 0 } else { chanAnn.NodeID1 = remotePubKey chanAnn.NodeID2 = localPubKey chanAnn.BitcoinKey1 = remoteFundingKey chanAnn.BitcoinKey2 = localFundingKey // If we're the second node then update the chanFlags to // indicate the "direction" of the update. chanFlags = 1 } chanUpdateAnn := &lnwire.ChannelUpdate{ ShortChannelID: shortChanID, ChainHash: chainHash, Timestamp: uint32(time.Now().Unix()), Flags: chanFlags, TimeLockDelta: uint16(f.cfg.DefaultRoutingPolicy.TimeLockDelta), HtlcMinimumMsat: f.cfg.DefaultRoutingPolicy.MinHTLC, BaseFee: uint32(f.cfg.DefaultRoutingPolicy.BaseFee), FeeRate: uint32(f.cfg.DefaultRoutingPolicy.FeeRate), } // With the channel update announcement constructed, we'll generate a // signature that signs a double-sha digest of the announcement. // This'll serve to authenticate this announcement and any other future // updates we may send. chanUpdateMsg, err := chanUpdateAnn.DataToSign() if err != nil { return nil, err } chanUpdateAnn.Signature, err = f.cfg.SignMessage(f.cfg.IDKey, chanUpdateMsg) if err != nil { return nil, errors.Errorf("unable to generate channel "+ "update announcement signature: %v", err) } // The channel existence proofs itself is currently announced in // distinct message. In order to properly authenticate this message, we // need two signatures: one under the identity public key used which // signs the message itself and another signature of the identity // public key under the funding key itself. // // TODO(roasbeef): use SignAnnouncement here instead? chanAnnMsg, err := chanAnn.DataToSign() if err != nil { return nil, err } nodeSig, err := f.cfg.SignMessage(f.cfg.IDKey, chanAnnMsg) if err != nil { return nil, errors.Errorf("unable to generate node "+ "signature for channel announcement: %v", err) } bitcoinSig, err := f.cfg.SignMessage(localFundingKey, chanAnnMsg) if err != nil { return nil, errors.Errorf("unable to generate bitcoin "+ "signature for node public key: %v", err) } // Finally, we'll generate the announcement proof which we'll use to // provide the other side with the necessary signatures required to // allow them to reconstruct the full channel announcement. proof := &lnwire.AnnounceSignatures{ ChannelID: chanID, ShortChannelID: shortChanID, NodeSignature: nodeSig, BitcoinSignature: bitcoinSig, } return &chanAnnouncement{ chanAnn: chanAnn, chanUpdateAnn: chanUpdateAnn, chanProof: proof, }, nil } // announceChannel announces a newly created channel to the rest of the network // by crafting the two authenticated announcements required for the peers on // the network to recognize the legitimacy of the channel. The crafted // announcements are then sent to the channel router to handle broadcasting to // the network during its next trickle. // This method is synchronous and will return when all the network requests // finish, either successfully or with an error. func (f *fundingManager) announceChannel(localIDKey, remoteIDKey, localFundingKey, remoteFundingKey *btcec.PublicKey, shortChanID lnwire.ShortChannelID, chanID lnwire.ChannelID) error { // First, we'll create the batch of announcements to be sent upon // initial channel creation. This includes the channel announcement // itself, the channel update announcement, and our half of the channel // proof needed to fully authenticate the channel. ann, err := f.newChanAnnouncement(localIDKey, remoteIDKey, localFundingKey, remoteFundingKey, shortChanID, chanID) if err != nil { fndgLog.Errorf("can't generate channel announcement: %v", err) return err } // With the announcements crafted, we'll now send the announcements to // the rest of the network. // // TODO(roasbeef): add flag that indicates if should be announced or // not // The announcement message consists of three distinct messages: // 1. channel announcement 2. channel update 3. channel proof // We must wait for them all to be successfully announced to the // network, and/ if either fails we consider the announcement // unsuccessful. if err = f.cfg.SendAnnouncement(ann.chanAnn); err != nil { return err } if err = f.cfg.SendAnnouncement(ann.chanUpdateAnn); err != nil { return err } if err = f.cfg.SendAnnouncement(ann.chanProof); err != nil { return err } // Now that the channel is announced to the network, we will also // obtain and send a node announcement. This is done since a node // announcement is only accepted after a channel is known for that // particular node, and this might be our first channel. nodeAnn, err := f.cfg.CurrentNodeAnnouncement() if err != nil { fndgLog.Errorf("can't generate node announcement: %v", err) return err } if err = f.cfg.SendAnnouncement(&nodeAnn); err != nil { return err } return nil } // initFundingWorkflow sends a message to the funding manager instructing it // to initiate a single funder workflow with the source peer. // TODO(roasbeef): re-visit blocking nature.. func (f *fundingManager) initFundingWorkflow(peerAddress *lnwire.NetAddress, req *openChanReq) { f.fundingRequests <- &initFundingMsg{ peerAddress: peerAddress, openChanReq: req, } } // handleInitFundingMsg creates a channel reservation within the daemon's // wallet, then sends a funding request to the remote peer kicking off the // funding workflow. func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) { var ( // TODO(roasbeef): add delay peerKey = msg.peerAddress.IdentityKey localAmt = msg.localFundingAmt remoteAmt = msg.remoteFundingAmt capacity = localAmt + remoteAmt ourDustLimit = lnwallet.DefaultDustLimit() ) fndgLog.Infof("Initiating fundingRequest(localAmt=%v, remoteAmt=%v, "+ "capacity=%v, chainhash=%v, addr=%v, dustLimit=%v)", localAmt, msg.pushAmt, capacity, msg.chainHash, msg.peerAddress.Address, ourDustLimit) // First, we'll query the fee estimator for a fee that should get the // commitment transaction into the next block (conf target of 1). We // target the next block here to ensure that we'll be able to execute a // timely unilateral channel closure if needed. // // TODO(roasbeef): shouldn't be targeting next block feePerWeight := btcutil.Amount(f.cfg.FeeEstimator.EstimateFeePerWeight(1)) // The protocol currently operates on the basis of fee-per-kw, so we'll // multiply the computed sat/weight by 1000 to arrive at fee-per-kw. feePerKw := feePerWeight * 1000 // Initialize a funding reservation with the local wallet. If the // wallet doesn't have enough funds to commit to this channel, then the // request will fail, and be aborted. reservation, err := f.cfg.Wallet.InitChannelReservation(capacity, localAmt, msg.pushAmt, feePerKw, peerKey, msg.peerAddress.Address, &msg.chainHash) if err != nil { msg.err <- err return } // Obtain a new pending channel ID which is used to track this // reservation throughout its lifetime. chanID := f.nextPendingChanID() fndgLog.Infof("Target sat/kw for pendingID(%x): %v", chanID, int64(feePerKw)) // If a pending channel map for this peer isn't already created, then // we create one, ultimately allowing us to track this pending // reservation within the target peer. peerIDKey := newSerializedKey(peerKey) f.resMtx.Lock() if _, ok := f.activeReservations[peerIDKey]; !ok { f.activeReservations[peerIDKey] = make(pendingChannels) } f.activeReservations[peerIDKey][chanID] = &reservationWithCtx{ chanAmt: capacity, reservation: reservation, peerAddress: msg.peerAddress, updates: msg.updates, err: msg.err, } f.resMtx.Unlock() // Using the RequiredRemoteDelay closure, we'll compute the remote CSV // delay we require given the total amount of funds within the channel. remoteCsvDelay := f.cfg.RequiredRemoteDelay(capacity) // Once the reservation has been created, and indexed, queue a funding // request to the remote peer, kicking off the funding workflow. ourContribution := reservation.OurContribution() // Finally, we'll use the current value of the channels and our default // policy to determine of required commitment constraints for the // remote party. chanReserve, maxValue, maxHtlcs := reservation.RemoteChanConstraints() fndgLog.Infof("Starting funding workflow with %v for pendingID(%x)", msg.peerAddress.Address, chanID) fundingOpen := lnwire.OpenChannel{ ChainHash: *f.cfg.Wallet.Cfg.NetParams.GenesisHash, PendingChannelID: chanID, FundingAmount: capacity, PushAmount: msg.pushAmt, DustLimit: ourContribution.DustLimit, MaxValueInFlight: maxValue, ChannelReserve: chanReserve, HtlcMinimum: ourContribution.MinHTLC, FeePerKiloWeight: uint32(feePerKw), CsvDelay: uint16(remoteCsvDelay), MaxAcceptedHTLCs: maxHtlcs, FundingKey: ourContribution.MultiSigKey, RevocationPoint: ourContribution.RevocationBasePoint, PaymentPoint: ourContribution.PaymentBasePoint, DelayedPaymentPoint: ourContribution.DelayBasePoint, FirstCommitmentPoint: ourContribution.FirstCommitmentPoint, } if err := f.cfg.SendToPeer(peerKey, &fundingOpen); err != nil { fndgLog.Errorf("Unable to send funding request message: %v", err) msg.err <- err return } } // waitUntilChannelOpen is designed to prevent other lnd subsystems from // sending new update messages to a channel before the channel is fully // opened. func (f *fundingManager) waitUntilChannelOpen(targetChan lnwire.ChannelID) { f.barrierMtx.RLock() barrier, ok := f.newChanBarriers[targetChan] f.barrierMtx.RUnlock() if ok { fndgLog.Tracef("waiting for chan barrier signal for ChanID(%v)", targetChan) select { case <-barrier: case <-f.quit: // TODO(roasbeef): add timer? break } fndgLog.Tracef("barrier for ChanID(%v) closed", targetChan) } } // processErrorGeneric sends a message to the fundingManager allowing it to // process the occurred generic error. func (f *fundingManager) processFundingError(err *lnwire.Error, peerAddress *lnwire.NetAddress) { f.fundingMsgs <- &fundingErrorMsg{err, peerAddress} } // handleErrorGenericMsg process the error which was received from remote peer, // depending on the type of error we should do different clean up steps and // inform the user about it. func (f *fundingManager) handleErrorMsg(fmsg *fundingErrorMsg) { protocolErr := fmsg.err peerKey := fmsg.peerAddress.IdentityKey chanID := fmsg.err.ChanID // First, we'll attempt to retrieve the funding workflow that this // error was tied to. If we're unable to do so, then we'll exit early // as this was an unwarranted error. resCtx, err := f.getReservationCtx(peerKey, chanID) if err != nil { fndgLog.Warnf("Received error for non-existent funding "+ "flow: %v", spew.Sdump(protocolErr)) return } // If we did indeed find the funding workflow, then we'll return the // error back to the caller (if any), and cancel the workflow itself. lnErr := lnwire.ErrorCode(protocolErr.Data[0]) fndgLog.Errorf("Received funding error from %x: %v", peerKey.SerializeCompressed(), lnErr, ) resCtx.err <- grpc.Errorf(lnErr.ToGrpcCode(), lnErr.String()) if _, err := f.cancelReservationCtx(peerKey, chanID); err != nil { fndgLog.Warnf("unable to delete reservation: %v", err) return } } // cancelReservationCtx do all needed work in order to securely cancel the // reservation. func (f *fundingManager) cancelReservationCtx(peerKey *btcec.PublicKey, pendingChanID [32]byte) (*reservationWithCtx, error) { fndgLog.Infof("Cancelling funding reservation for node_key=%x, "+ "chan_id=%x", peerKey.SerializeCompressed(), pendingChanID[:]) ctx, err := f.getReservationCtx(peerKey, pendingChanID) if err != nil { return nil, errors.Errorf("unable to find reservation: %v", err) } if err := ctx.reservation.Cancel(); err != nil { return nil, errors.Errorf("unable to cancel reservation: %v", err) } f.deleteReservationCtx(peerKey, pendingChanID) return ctx, nil } // deleteReservationCtx deletes the reservation uniquely identified by the // target public key of the peer, and the specified pending channel ID. func (f *fundingManager) deleteReservationCtx(peerKey *btcec.PublicKey, pendingChanID [32]byte) { // TODO(roasbeef): possibly cancel funding barrier in peer's // channelManager? peerIDKey := newSerializedKey(peerKey) f.resMtx.Lock() delete(f.activeReservations[peerIDKey], pendingChanID) f.resMtx.Unlock() } // getReservationCtx returns the reservation context for a particular pending // channel ID for a target peer. func (f *fundingManager) getReservationCtx(peerKey *btcec.PublicKey, pendingChanID [32]byte) (*reservationWithCtx, error) { peerIDKey := newSerializedKey(peerKey) f.resMtx.RLock() resCtx, ok := f.activeReservations[peerIDKey][pendingChanID] f.resMtx.RUnlock() if !ok { return nil, errors.Errorf("unknown channel (id: %x)", pendingChanID[:]) } return resCtx, nil } func copyPubKey(pub *btcec.PublicKey) *btcec.PublicKey { return &btcec.PublicKey{ Curve: btcec.S256(), X: pub.X, Y: pub.Y, } } // saveChannelOpeningState saves the channelOpeningState for the provided // chanPoint to the channelOpeningStateBucket. func (f *fundingManager) saveChannelOpeningState(chanPoint *wire.OutPoint, state channelOpeningState, shortChanID *lnwire.ShortChannelID) error { return f.cfg.Wallet.Cfg.Database.Update(func(tx *bolt.Tx) error { bucket, err := tx.CreateBucketIfNotExists(channelOpeningStateBucket) if err != nil { return err } var outpointBytes bytes.Buffer if err = writeOutpoint(&outpointBytes, chanPoint); err != nil { return err } // Save state and the uint64 representation of the shortChanID // for later use. scratch := make([]byte, 10) byteOrder.PutUint16(scratch[:2], uint16(state)) byteOrder.PutUint64(scratch[2:], shortChanID.ToUint64()) if err = bucket.Put(outpointBytes.Bytes(), scratch); err != nil { return err } return nil }) } // getChannelOpeningState fetches the channelOpeningState for the provided // chanPoint from the database, or returns ErrChannelNotFound if the channel // is not found. func (f *fundingManager) getChannelOpeningState(chanPoint *wire.OutPoint) ( channelOpeningState, *lnwire.ShortChannelID, error) { var state channelOpeningState var shortChanID lnwire.ShortChannelID err := f.cfg.Wallet.Cfg.Database.View(func(tx *bolt.Tx) error { bucket := tx.Bucket(channelOpeningStateBucket) if bucket == nil { // If the bucket does not exist, it means we never added // a channel to the db, so return ErrChannelNotFound. return ErrChannelNotFound } var outpointBytes bytes.Buffer if err := writeOutpoint(&outpointBytes, chanPoint); err != nil { return err } value := bucket.Get(outpointBytes.Bytes()) if value == nil { return ErrChannelNotFound } state = channelOpeningState(byteOrder.Uint16(value[:2])) shortChanID = lnwire.NewShortChanIDFromInt(byteOrder.Uint64(value[2:])) return nil }) if err != nil { return 0, nil, err } return state, &shortChanID, nil } // deleteChannelOpeningState removes any state for chanPoint from the database. func (f *fundingManager) deleteChannelOpeningState(chanPoint *wire.OutPoint) error { return f.cfg.Wallet.Cfg.Database.Update(func(tx *bolt.Tx) error { bucket := tx.Bucket(channelOpeningStateBucket) if bucket == nil { return fmt.Errorf("Bucket not found") } var outpointBytes bytes.Buffer if err := writeOutpoint(&outpointBytes, chanPoint); err != nil { return err } if err := bucket.Delete(outpointBytes.Bytes()); err != nil { return err } return nil }) }