package main import ( "bytes" "encoding/binary" "sync" "sync/atomic" "time" "golang.org/x/crypto/salsa20" "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/lnrpc" "github.com/lightningnetwork/lnd/lnwallet" "github.com/lightningnetwork/lnd/lnwire" "github.com/roasbeef/btcd/btcec" "github.com/roasbeef/btcd/txscript" "github.com/roasbeef/btcd/wire" "github.com/roasbeef/btcutil" "google.golang.org/grpc" ) const ( // TODO(roasbeef): tune msgBufferSize = 50 ) // 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 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 } // fundingRequestMsg couples an lnwire.SingleFundingRequest 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 fundingRequestMsg struct { msg *lnwire.SingleFundingRequest peerAddress *lnwire.NetAddress } // fundingResponseMsg couples an lnwire.SingleFundingResponse 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 fundingResponseMsg struct { msg *lnwire.SingleFundingResponse peerAddress *lnwire.NetAddress } // fundingCompleteMsg couples an lnwire.SingleFundingComplete 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 fundingCompleteMsg struct { msg *lnwire.SingleFundingComplete peerAddress *lnwire.NetAddress } // fundingSignCompleteMsg couples an lnwire.SingleFundingSignComplete 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 fundingSignCompleteMsg struct { msg *lnwire.SingleFundingSignComplete 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. 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 // 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 broadcasted 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. SignMessage func(pubKey *btcec.PublicKey, msg []byte) (*btcec.Signature, 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 } // 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 // channelReservations is a map which houses the state of all pending // funding workflows. resMtx sync.RWMutex activeReservations map[serializedPubKey]pendingChannels // 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{} quit chan struct{} wg sync.WaitGroup } // 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), newChanBarriers: make(map[lnwire.ChannelID]chan struct{}), fundingMsgs: make(chan interface{}, msgBufferSize), fundingRequests: make(chan *initFundingMsg, msgBufferSize), 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. pendingChannels, err := f.cfg.Wallet.ChannelDB.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() doneChan := make(chan struct{}) go f.waitForFundingConfirmation(channel, doneChan) } 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 } type numPendingReq struct { resp chan uint32 err chan error } // NumPendingChannels returns the number of pending channels currently // progressing through the reservation workflow. func (f *fundingManager) NumPendingChannels() (uint32, error) { respChan := make(chan uint32, 1) errChan := make(chan error) req := &numPendingReq{ resp: respChan, err: errChan, } f.queries <- req return <-respChan, <-errChan } // 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 } // 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 *fundingRequestMsg: f.handleFundingRequest(fmsg) case *fundingResponseMsg: f.handleFundingResponse(fmsg) case *fundingCompleteMsg: f.handleFundingComplete(fmsg) case *fundingSignCompleteMsg: f.handleFundingSignComplete(fmsg) case *fundingLockedMsg: f.handleFundingLocked(fmsg) case *fundingErrorMsg: f.handleErrorMsg(fmsg) } case req := <-f.fundingRequests: f.handleInitFundingMsg(req) case req := <-f.queries: switch msg := req.(type) { case *numPendingReq: f.handleNumPending(msg) case *pendingChansReq: f.handlePendingChannels(msg) } case <-f.quit: return } } } // handleNumPending handles a request for the total number of pending channels. func (f *fundingManager) handleNumPending(msg *numPendingReq) { // TODO(roasbeef): remove this method? dbPendingChannels, err := f.cfg.Wallet.ChannelDB.FetchPendingChannels() if err != nil { close(msg.resp) msg.err <- err return } msg.resp <- uint32(len(dbPendingChannels)) msg.err <- nil } // 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.ChannelDB.FetchPendingChannels() if err != nil { msg.resp <- nil msg.err <- err return } for _, dbPendingChan := range dbPendingChannels { pendingChan := &pendingChannel{ identityPub: dbPendingChan.IdentityPub, channelPoint: dbPendingChan.ChanID, capacity: dbPendingChan.Capacity, localBalance: dbPendingChan.OurBalance, remoteBalance: dbPendingChan.TheirBalance, } pendingChannels = append(pendingChannels, pendingChan) } msg.resp <- pendingChannels msg.err <- nil } // processFundingRequest sends a message to the fundingManager allowing it to // initiate the new funding workflow with the source peer. func (f *fundingManager) processFundingRequest(msg *lnwire.SingleFundingRequest, peerAddress *lnwire.NetAddress) { f.fundingMsgs <- &fundingRequestMsg{msg, peerAddress} } // handleFundingRequest creates an initial 'ChannelReservation' within // the wallet, then responds to the source peer with a single funder response // message progressing the funding workflow. // TODO(roasbeef): add error chan to all, let channelManager handle // error+propagate func (f *fundingManager) handleFundingRequest(fmsg *fundingRequestMsg) { // 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) if len(f.activeReservations[peerIDKey]) >= cfg.MaxPendingChannels { errMsg := &lnwire.Error{ ChanID: fmsg.msg.PendingChannelID, Code: lnwire.ErrMaxPendingChannels, Data: []byte("Number of pending channels exceed maximum"), } if err := f.cfg.SendToPeer(fmsg.peerAddress.IdentityKey, errMsg); err != nil { fndgLog.Errorf("unable to send max pending channels "+ "message to peer: %v", err) return } 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 { errMsg := &lnwire.Error{ ChanID: fmsg.msg.PendingChannelID, Code: lnwire.ErrSynchronizingChain, Data: []byte("Synchronizing blockchain"), } if err := f.cfg.SendToPeer(fmsg.peerAddress.IdentityKey, errMsg); err != nil { fndgLog.Errorf("unable to send error message to peer %v", err) return } return } msg := fmsg.msg amt := msg.FundingAmount delay := msg.CsvDelay // TODO(roasbeef): error if funding flow already ongoing fndgLog.Infof("Recv'd fundingRequest(amt=%v, delay=%v, pendingId=%x) "+ "from peer(%x)", amt, msg.PushSatoshis, delay, msg.PendingChannelID, fmsg.peerAddress.IdentityKey.SerializeCompressed()) ourDustLimit := lnwallet.DefaultDustLimit() theirDustlimit := msg.DustLimit // 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 reservation, err := f.cfg.Wallet.InitChannelReservation(amt, 0, fmsg.peerAddress.IdentityKey, fmsg.peerAddress.Address, uint16(fmsg.msg.ConfirmationDepth), delay, ourDustLimit, msg.PushSatoshis) if err != nil { // TODO(roasbeef): push ErrorGeneric message fndgLog.Errorf("Unable to initialize reservation: %v", err) return } reservation.SetTheirDustLimit(theirDustlimit) // 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, err: make(chan error, 1), peerAddress: fmsg.peerAddress, } f.resMtx.Unlock() cancelReservation := func() { _, err := f.cancelReservationCtx(fmsg.peerAddress.IdentityKey, msg.PendingChannelID) if err != nil { fndgLog.Errorf("unable to cancel reservation: %v", err) } } // With our portion of the reservation initialized, process the // initiators contribution to the channel. _, addrs, _, err := txscript.ExtractPkScriptAddrs(msg.DeliveryPkScript, activeNetParams.Params) if err != nil { fndgLog.Errorf("Unable to extract addresses from script: %v", err) cancelReservation() return } contribution := &lnwallet.ChannelContribution{ FundingAmount: amt, MultiSigKey: copyPubKey(msg.ChannelDerivationPoint), CommitKey: copyPubKey(msg.CommitmentKey), DeliveryAddress: addrs[0], CsvDelay: delay, } if err := reservation.ProcessSingleContribution(contribution); err != nil { fndgLog.Errorf("unable to add contribution reservation: %v", err) cancelReservation() return } fndgLog.Infof("Sending fundingResp for pendingID(%x)", msg.PendingChannelID) // With the initiator's contribution recorded, respond with our // contribution in the next message of the workflow. ourContribution := reservation.OurContribution() deliveryScript, err := txscript.PayToAddrScript(ourContribution.DeliveryAddress) if err != nil { fndgLog.Errorf("unable to convert address to pkscript: %v", err) cancelReservation() return } fundingResp := lnwire.NewSingleFundingResponse(msg.PendingChannelID, ourContribution.RevocationKey, ourContribution.CommitKey, ourContribution.MultiSigKey, ourContribution.CsvDelay, deliveryScript, ourDustLimit, msg.ConfirmationDepth) if err := f.cfg.SendToPeer(fmsg.peerAddress.IdentityKey, fundingResp); err != nil { fndgLog.Errorf("unable to send funding response to peer: %v", err) cancelReservation() return } } // processFundingRequest sends a message to the fundingManager allowing it to // continue the second phase of a funding workflow with the target peer. func (f *fundingManager) processFundingResponse(msg *lnwire.SingleFundingResponse, peerAddress *lnwire.NetAddress) { f.fundingMsgs <- &fundingResponseMsg{msg, peerAddress} } // handleFundingResponse 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) handleFundingResponse(fmsg *fundingResponseMsg) { 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 } cancelReservation := func() { _, err := f.cancelReservationCtx(peerKey, pendingChanID) if err != nil { fndgLog.Errorf("unable to cancel reservation: %v", err) } } fndgLog.Infof("Recv'd fundingResponse for pendingID(%x)", pendingChanID) resCtx.reservation.SetTheirDustLimit(msg.DustLimit) // 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. _, addrs, _, err := txscript.ExtractPkScriptAddrs(msg.DeliveryPkScript, activeNetParams.Params) if err != nil { fndgLog.Errorf("Unable to extract addresses from script: %v", err) cancelReservation() resCtx.err <- err return } contribution := &lnwallet.ChannelContribution{ FundingAmount: 0, MultiSigKey: copyPubKey(msg.ChannelDerivationPoint), CommitKey: copyPubKey(msg.CommitmentKey), DeliveryAddress: addrs[0], RevocationKey: copyPubKey(msg.RevocationKey), CsvDelay: msg.CsvDelay, } if err := resCtx.reservation.ProcessContribution(contribution); err != nil { fndgLog.Errorf("Unable to process contribution from %v: %v", fmsg.peerAddress.IdentityKey, err) cancelReservation() resCtx.err <- err return } // 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) cancelReservation() 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() fndgLog.Infof("Generated ChannelPoint(%v) for pendingID(%x)", outPoint, pendingChanID) revocationKey := resCtx.reservation.OurContribution().RevocationKey obsfucator := resCtx.reservation.StateNumObfuscator() fundingComplete := lnwire.NewSingleFundingComplete(pendingChanID, *outPoint, commitSig, revocationKey, obsfucator) err = f.cfg.SendToPeer(fmsg.peerAddress.IdentityKey, fundingComplete) if err != nil { fndgLog.Errorf("Unable to send funding complete message: %v", err) cancelReservation() resCtx.err <- err return } } // processFundingComplete queues a funding complete message coupled with the // source peer to the fundingManager. func (f *fundingManager) processFundingComplete(msg *lnwire.SingleFundingComplete, peerAddress *lnwire.NetAddress) { f.fundingMsgs <- &fundingCompleteMsg{msg, peerAddress} } // handleFundingComplete 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) handleFundingComplete(fmsg *fundingCompleteMsg) { 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:%v)", peerKey, pendingChanID) return } cancelReservation := func() { _, err := f.cancelReservationCtx(peerKey, pendingChanID) if err != nil { fndgLog.Errorf("unable to cancel reservation: %v", err) } } // 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 // inititator's commitment transaction, then send our own if it's valid. // TODO(roasbeef): make case (p vs P) consistent throughout fundingOut := fmsg.msg.FundingOutPoint fndgLog.Infof("completing pendingID(%x) with ChannelPoint(%v)", pendingChanID, fundingOut) revokeKey := copyPubKey(fmsg.msg.RevocationKey) obsfucator := fmsg.msg.StateHintObsfucator commitSig := fmsg.msg.CommitSignature.Serialize() // 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. completeChan, err := resCtx.reservation.CompleteReservationSingle( revokeKey, &fundingOut, commitSig, obsfucator) if err != nil { // TODO(roasbeef): better error logging: peerID, channelID, etc. fndgLog.Errorf("unable to complete single reservation: %v", err) cancelReservation() return } // 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) cancelReservation() 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(&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) signComplete := lnwire.NewSingleFundingSignComplete(pendingChanID, ourCommitSig) if err := f.cfg.SendToPeer(peerKey, signComplete); err != nil { fndgLog.Errorf("unable to send signComplete message: %v", err) cancelReservation() return } go func() { doneChan := make(chan struct{}) go f.waitForFundingConfirmation(completeChan, doneChan) <-doneChan f.deleteReservationCtx(peerKey, fmsg.msg.PendingChannelID) }() } // processFundingSignComplete sends a single funding sign complete message // along with the source peer to the funding manager. func (f *fundingManager) processFundingSignComplete(msg *lnwire.SingleFundingSignComplete, peerAddress *lnwire.NetAddress) { f.fundingMsgs <- &fundingSignCompleteMsg{msg, peerAddress} } // handleFundingSignComplete 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) handleFundingSignComplete(fmsg *fundingSignCompleteMsg) { chanID := fmsg.msg.PendingChannelID peerKey := fmsg.peerAddress.IdentityKey resCtx, err := f.getReservationCtx(peerKey, chanID) if err != nil { fndgLog.Warnf("can't find reservation (peerID:%v, chanID:%v)", peerKey, chanID) return } // 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.CommitSignature.Serialize() completeChan, err := resCtx.reservation.CompleteReservation(nil, commitSig) if err != nil { fndgLog.Errorf("unable to complete reservation sign complete: %v", err) resCtx.err <- err if _, err := f.cancelReservationCtx(peerKey, chanID); err != nil { fndgLog.Errorf("unable to cancel reservation: %v", err) } return } fundingPoint := resCtx.reservation.FundingOutpoint() fndgLog.Infof("Finalizing pendingID(%x) over ChannelPoint(%v), "+ "waiting for channel open on-chain", chanID, 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{}) go f.waitForFundingConfirmation(completeChan, 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, fmsg.msg.PendingChannelID) }() } // 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. func (f *fundingManager) waitForFundingConfirmation(completeChan *channeldb.OpenChannel, 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) 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) // Wait until the specified number of confirmations has been reached, // or the wallet signals a shutdown. confDetails, ok := <-confNtfn.Confirmed 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) // Now that the channel has been fully confirmed, we'll mark it as open // within the database. completeChan.IsPending = false err = f.cfg.Wallet.ChannelDB.MarkChannelAsOpen(&fundingPoint) if err != nil { fndgLog.Errorf("error setting channel pending flag to false: "+ "%v", err) return } // With the channel marked open, we'll create the state-machine object // which wraps the database state. channel, err := lnwallet.NewLightningChannel(nil, nil, completeChan) if err != nil { fndgLog.Errorf("error creating new lightning channel: %v", err) return } // 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) f.cfg.SendToPeer(completeChan.IdentityPub, fundingLockedMsg) // 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), } 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. go f.announceChannel(f.cfg.IDKey, completeChan.IdentityPub, channel.LocalFundingKey, channel.RemoteFundingKey, shortChanID, chanID) 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) { // 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 } // 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) { // 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, } // 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 } // TODO(roasbeef): populate proper FeeSchema chanUpdateAnn := &lnwire.ChannelUpdate{ ShortChannelID: shortChanID, Timestamp: uint32(time.Now().Unix()), Flags: chanFlags, TimeLockDelta: 1, HtlcMinimumMsat: 0, FeeBaseMsat: 0, FeeProportionalMillionths: 0, } // 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): need to revisit, ensure signatures are signed // properly 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, selfBytes) 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. func (f *fundingManager) announceChannel(localIDKey, remoteIDKey, localFundingKey, remoteFundingKey *btcec.PublicKey, shortChanID lnwire.ShortChannelID, chanID lnwire.ChannelID) { ann, err := f.newChanAnnouncement(localIDKey, remoteIDKey, localFundingKey, remoteFundingKey, shortChanID, chanID) if err != nil { fndgLog.Errorf("can't generate channel announcement: %v", err) return } f.cfg.SendAnnouncement(ann.chanAnn) f.cfg.SendAnnouncement(ann.chanUpdateAnn) f.cfg.SendAnnouncement(ann.chanProof) } // 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 numConfs = msg.numConfs ourDustLimit = lnwallet.DefaultDustLimit() ) fndgLog.Infof("Initiating fundingRequest(localAmt=%v, remoteAmt=%v, "+ "capacity=%v, numConfs=%v, addr=%v, dustLimit=%v)", localAmt, msg.pushAmt, capacity, numConfs, msg.peerAddress.Address, ourDustLimit) // 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, peerKey, msg.peerAddress.Address, uint16(numConfs), 4, ourDustLimit, msg.pushAmt) 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() // 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{ reservation: reservation, peerAddress: msg.peerAddress, updates: msg.updates, err: msg.err, } f.resMtx.Unlock() // Once the reservation has been created, and indexed, queue a funding // request to the remote peer, kicking off the funding workflow. contribution := reservation.OurContribution() deliveryScript, err := txscript.PayToAddrScript(contribution.DeliveryAddress) if err != nil { fndgLog.Errorf("Unable to convert address to pkscript: %v", err) msg.err <- err return } fndgLog.Infof("Starting funding workflow with %v for pendingID(%x)", msg.peerAddress.Address, chanID) // TODO(roasbeef): add FundingRequestFromContribution func // TODO(roasbeef): need to set fee/kb fundingReq := lnwire.NewSingleFundingRequest( chanID, msg.channelType, msg.coinType, 0, // TODO(roasbeef): grab from fee estimation model capacity, contribution.CsvDelay, contribution.CommitKey, contribution.MultiSigKey, deliveryScript, ourDustLimit, msg.pushAmt, numConfs, ) if err := f.cfg.SendToPeer(peerKey, fundingReq); 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) { e := fmsg.err switch e.Code { case lnwire.ErrMaxPendingChannels: fallthrough case lnwire.ErrSynchronizingChain: peerKey := fmsg.peerAddress.IdentityKey chanID := fmsg.err.ChanID ctx, err := f.cancelReservationCtx(peerKey, chanID) if err != nil { fndgLog.Warnf("unable to delete reservation: %v", err) ctx.err <- err return } fndgLog.Errorf("Received funding error from %x: %v", peerKey.SerializeCompressed(), newLogClosure(func() string { return spew.Sdump(e) }), ) ctx.err <- grpc.Errorf(e.Code.ToGrpcCode(), string(e.Data)) return default: fndgLog.Warnf("unknown funding error (%v:%v)", e.Code, e.Data) } } // cancelReservationCtx do all needed work in order to securely cancel the // reservation. func (f *fundingManager) cancelReservationCtx(peerKey *btcec.PublicKey, chanID [32]byte) (*reservationWithCtx, error) { fndgLog.Infof("Cancelling funding reservation for node_key=%x, "+ "chan_id=%x", peerKey.SerializeCompressed(), chanID) ctx, err := f.getReservationCtx(peerKey, chanID) if err != nil { return nil, errors.Errorf("can't find reservation: %v", err) } if err := ctx.reservation.Cancel(); err != nil { return nil, errors.Errorf("can't cancel reservation: %v", err) } f.deleteReservationCtx(peerKey, chanID) return ctx, nil } // deleteReservationCtx is needed in order to securely delete the reservation. func (f *fundingManager) deleteReservationCtx(peerKey *btcec.PublicKey, chanID [32]byte) { // TODO(roasbeef): possibly cancel funding barrier in peer's // channelManager? peerIDKey := newSerializedKey(peerKey) f.resMtx.Lock() delete(f.activeReservations[peerIDKey], chanID) f.resMtx.Unlock() } // getReservationCtx returns the reservation context by peer id and channel id. func (f *fundingManager) getReservationCtx(peerKey *btcec.PublicKey, chanID [32]byte) (*reservationWithCtx, error) { peerIDKey := newSerializedKey(peerKey) f.resMtx.RLock() resCtx, ok := f.activeReservations[peerIDKey][chanID] f.resMtx.RUnlock() if !ok { return nil, errors.Errorf("unknown channel (id: %v)", chanID) } return resCtx, nil } func copyPubKey(pub *btcec.PublicKey) *btcec.PublicKey { return &btcec.PublicKey{ Curve: btcec.S256(), X: pub.X, Y: pub.Y, } }