package peer import ( "bytes" "container/list" "errors" "fmt" "net" "sync" "sync/atomic" "time" "github.com/btcsuite/btcd/btcec" "github.com/btcsuite/btcd/chaincfg/chainhash" "github.com/btcsuite/btcd/connmgr" "github.com/btcsuite/btcd/txscript" "github.com/btcsuite/btcd/wire" "github.com/davecgh/go-spew/spew" "github.com/lightningnetwork/lnd/buffer" "github.com/lightningnetwork/lnd/chainntnfs" "github.com/lightningnetwork/lnd/channeldb" "github.com/lightningnetwork/lnd/channelnotifier" "github.com/lightningnetwork/lnd/contractcourt" "github.com/lightningnetwork/lnd/discovery" "github.com/lightningnetwork/lnd/feature" "github.com/lightningnetwork/lnd/fmgr" "github.com/lightningnetwork/lnd/htlcswitch" "github.com/lightningnetwork/lnd/htlcswitch/hodl" "github.com/lightningnetwork/lnd/htlcswitch/hop" "github.com/lightningnetwork/lnd/input" "github.com/lightningnetwork/lnd/invoices" "github.com/lightningnetwork/lnd/lnpeer" "github.com/lightningnetwork/lnd/lnwallet" "github.com/lightningnetwork/lnd/lnwallet/chainfee" "github.com/lightningnetwork/lnd/lnwallet/chancloser" "github.com/lightningnetwork/lnd/lnwire" "github.com/lightningnetwork/lnd/netann" "github.com/lightningnetwork/lnd/pool" "github.com/lightningnetwork/lnd/queue" "github.com/lightningnetwork/lnd/ticker" "github.com/lightningnetwork/lnd/watchtower/wtclient" ) const ( // pingInterval is the interval at which ping messages are sent. pingInterval = 1 * time.Minute // idleTimeout is the duration of inactivity before we time out a peer. idleTimeout = 5 * time.Minute // writeMessageTimeout is the timeout used when writing a message to the // peer. writeMessageTimeout = 5 * time.Second // readMessageTimeout is the timeout used when reading a message from a // peer. readMessageTimeout = 5 * time.Second // handshakeTimeout is the timeout used when waiting for the peer's init // message. handshakeTimeout = 15 * time.Second // outgoingQueueLen is the buffer size of the channel which houses // messages to be sent across the wire, requested by objects outside // this struct. outgoingQueueLen = 50 // ErrorBufferSize is the number of historic peer errors that we store. ErrorBufferSize = 10 ) var ( // ErrChannelNotFound is an error returned when a channel is queried and // either the Brontide doesn't know of it, or the channel in question // is pending. ErrChannelNotFound = fmt.Errorf("channel not found") ) // outgoingMsg packages an lnwire.Message to be sent out on the wire, along with // a buffered channel which will be sent upon once the write is complete. This // buffered channel acts as a semaphore to be used for synchronization purposes. type outgoingMsg struct { priority bool msg lnwire.Message errChan chan error // MUST be buffered. } // newChannelMsg packages a channeldb.OpenChannel with a channel that allows // the receiver of the request to report when the channel creation process has // completed. type newChannelMsg struct { channel *channeldb.OpenChannel err chan error } // closeMsg is a wrapper struct around any wire messages that deal with the // cooperative channel closure negotiation process. This struct includes the // raw channel ID targeted along with the original message. type closeMsg struct { cid lnwire.ChannelID msg lnwire.Message } // PendingUpdate describes the pending state of a closing channel. type PendingUpdate struct { Txid []byte OutputIndex uint32 } // ChannelCloseUpdate contains the outcome of the close channel operation. type ChannelCloseUpdate struct { ClosingTxid []byte Success bool } // TimestampedError is a timestamped error that is used to store the most recent // errors we have experienced with our peers. type TimestampedError struct { Error error Timestamp time.Time } // Config defines configuration fields that are necessary for a peer object // to function. type Config struct { // Conn is the underlying network connection for this peer. Conn MessageConn // ConnReq stores information related to the persistent connection request // for this peer. ConnReq *connmgr.ConnReq // PubKeyBytes is the serialized, compressed public key of this peer. PubKeyBytes [33]byte // Addr is the network address of the peer. Addr *lnwire.NetAddress // Inbound indicates whether or not the peer is an inbound peer. Inbound bool // Features is the set of features that we advertise to the remote party. Features *lnwire.FeatureVector // LegacyFeatures is the set of features that we advertise to the remote // peer for backwards compatibility. Nodes that have not implemented // flat features will still be able to read our feature bits from the // legacy global field, but we will also advertise everything in the // default features field. LegacyFeatures *lnwire.FeatureVector // OutgoingCltvRejectDelta defines the number of blocks before expiry of // an htlc where we don't offer it anymore. OutgoingCltvRejectDelta uint32 // ChanActiveTimeout specifies the duration the peer will wait to request // a channel reenable, beginning from the time the peer was started. ChanActiveTimeout time.Duration // ErrorBuffer stores a set of errors related to a peer. It contains error // messages that our peer has recently sent us over the wire and records of // unknown messages that were sent to us so that we can have a full track // record of the communication errors we have had with our peer. If we // choose to disconnect from a peer, it also stores the reason we had for // disconnecting. ErrorBuffer *queue.CircularBuffer // WritePool is the task pool that manages reuse of write buffers. Write // tasks are submitted to the pool in order to conserve the total number of // write buffers allocated at any one time, and decouple write buffer // allocation from the peer life cycle. WritePool *pool.Write // ReadPool is the task pool that manages reuse of read buffers. ReadPool *pool.Read // Switch is a pointer to the htlcswitch. It is used to setup, get, and // tear-down ChannelLinks. Switch *htlcswitch.Switch // InterceptSwitch is a pointer to the InterceptableSwitch, a wrapper around // the regular Switch. We only export it here to pass ForwardPackets to the // ChannelLinkConfig. InterceptSwitch *htlcswitch.InterceptableSwitch // ChannelDB is used to fetch opened channels, and closed channels. ChannelDB *channeldb.DB // ChannelGraph is a pointer to the channel graph which is used to // query information about the set of known active channels. ChannelGraph *channeldb.ChannelGraph // ChainArb is used to subscribe to channel events, update contract signals, // and force close channels. ChainArb *contractcourt.ChainArbitrator // AuthGossiper is needed so that the Brontide impl can register with the // gossiper and process remote channel announcements. AuthGossiper *discovery.AuthenticatedGossiper // ChanStatusMgr is used to set or un-set the disabled bit in channel // updates. ChanStatusMgr *netann.ChanStatusManager // ChainIO is used to retrieve the best block. ChainIO lnwallet.BlockChainIO // FeeEstimator is used to compute our target ideal fee-per-kw when // initializing the coop close process. FeeEstimator chainfee.Estimator // Signer is used when creating *lnwallet.LightningChannel instances. Signer input.Signer // SigPool is used when creating *lnwallet.LightningChannel instances. SigPool *lnwallet.SigPool // Wallet is used to publish transactions and generates delivery // scripts during the coop close process. Wallet *lnwallet.LightningWallet // ChainNotifier is used to receive confirmations of a coop close // transaction. ChainNotifier chainntnfs.ChainNotifier // RoutingPolicy is used to set the forwarding policy for links created by // the Brontide. RoutingPolicy htlcswitch.ForwardingPolicy // Sphinx is used when setting up ChannelLinks so they can decode sphinx // onion blobs. Sphinx *hop.OnionProcessor // WitnessBeacon is used when setting up ChannelLinks so they can add any // preimages that they learn. WitnessBeacon contractcourt.WitnessBeacon // Invoices is passed to the ChannelLink on creation and handles all // invoice-related logic. Invoices *invoices.InvoiceRegistry // ChannelNotifier is used by the link to notify other sub-systems about // channel-related events and by the Brontide to subscribe to // ActiveLinkEvents. ChannelNotifier *channelnotifier.ChannelNotifier // HtlcNotifier is used when creating a ChannelLink. HtlcNotifier *htlcswitch.HtlcNotifier // TowerClient is used by legacy channels to backup revoked states. TowerClient wtclient.Client // AnchorTowerClient is used by anchor channels to backup revoked // states. AnchorTowerClient wtclient.Client // DisconnectPeer is used to disconnect this peer if the cooperative close // process fails. DisconnectPeer func(*btcec.PublicKey) error // GenNodeAnnouncement is used to send our node announcement to the remote // on startup. GenNodeAnnouncement func(bool, ...netann.NodeAnnModifier) (lnwire.NodeAnnouncement, error) // PrunePersistentPeerConnection is used to remove all internal state // related to this peer in the server. PrunePersistentPeerConnection func([33]byte) // FetchLastChanUpdate fetches our latest channel update for a target // channel. FetchLastChanUpdate func(lnwire.ShortChannelID) (*lnwire.ChannelUpdate, error) // FundingManager is an implementation of the fmgr.Manager interface. FundingManager fmgr.Manager // Hodl is used when creating ChannelLinks to specify HodlFlags as // breakpoints in dev builds. Hodl *hodl.Config // UnsafeReplay is used when creating ChannelLinks to specify whether or // not to replay adds on its commitment tx. UnsafeReplay bool // MaxOutgoingCltvExpiry is used when creating ChannelLinks and is the max // number of blocks that funds could be locked up for when forwarding // payments. MaxOutgoingCltvExpiry uint32 // MaxChannelFeeAllocation is used when creating ChannelLinks and is the // maximum percentage of total funds that can be allocated to a channel's // commitment fee. This only applies for the initiator of the channel. MaxChannelFeeAllocation float64 // ServerPubKey is the serialized, compressed public key of our lnd node. // It is used to determine which policy (channel edge) to pass to the // ChannelLink. ServerPubKey [33]byte // Quit is the server's quit channel. If this is closed, we halt operation. Quit chan struct{} } // Brontide is an active peer on the Lightning Network. This struct is responsible // for managing any channel state related to this peer. To do so, it has // several helper goroutines to handle events such as HTLC timeouts, new // funding workflow, and detecting an uncooperative closure of any active // channels. // TODO(roasbeef): proper reconnection logic type Brontide struct { // MUST be used atomically. started int32 disconnect int32 // MUST be used atomically. bytesReceived uint64 bytesSent uint64 // pingTime is a rough estimate of the RTT (round-trip-time) between us // and the connected peer. This time is expressed in microseconds. // To be used atomically. // TODO(roasbeef): also use a WMA or EMA? pingTime int64 // pingLastSend is the Unix time expressed in nanoseconds when we sent // our last ping message. To be used atomically. pingLastSend int64 cfg Config // activeSignal when closed signals that the peer is now active and // ready to process messages. activeSignal chan struct{} // startTime is the time this peer connection was successfully established. // It will be zero for peers that did not successfully call Start(). startTime time.Time // sendQueue is the channel which is used to queue outgoing messages to be // written onto the wire. Note that this channel is unbuffered. sendQueue chan outgoingMsg // outgoingQueue is a buffered channel which allows second/third party // objects to queue messages to be sent out on the wire. outgoingQueue chan outgoingMsg // activeChanMtx protects access to the activeChannels and // addedChannels maps. activeChanMtx sync.RWMutex // activeChannels is a map which stores the state machines of all // active channels. Channels are indexed into the map by the txid of // the funding transaction which opened the channel. // // NOTE: On startup, pending channels are stored as nil in this map. // Confirmed channels have channel data populated in the map. This means // that accesses to this map should nil-check the LightningChannel to // see if this is a pending channel or not. The tradeoff here is either // having two maps everywhere (one for pending, one for confirmed chans) // or having an extra nil-check per access. activeChannels map[lnwire.ChannelID]*lnwallet.LightningChannel // addedChannels tracks any new channels opened during this peer's // lifecycle. We use this to filter out these new channels when the time // comes to request a reenable for active channels, since they will have // waited a shorter duration. addedChannels map[lnwire.ChannelID]struct{} // newChannels is used by the fundingManager to send fully opened // channels to the source peer which handled the funding workflow. newChannels chan *newChannelMsg // activeMsgStreams is a map from channel id to the channel streams that // proxy messages to individual, active links. activeMsgStreams map[lnwire.ChannelID]*msgStream // activeChanCloses is a map that keeps track of all the active // cooperative channel closures. Any channel closing messages are directed // to one of these active state machines. Once the channel has been closed, // the state machine will be deleted from the map. activeChanCloses map[lnwire.ChannelID]*chancloser.ChanCloser // localCloseChanReqs is a channel in which any local requests to close // a particular channel are sent over. localCloseChanReqs chan *htlcswitch.ChanClose // linkFailures receives all reported channel failures from the switch, // and instructs the channelManager to clean remaining channel state. linkFailures chan linkFailureReport // chanCloseMsgs is a channel that any message related to channel // closures are sent over. This includes lnwire.Shutdown message as // well as lnwire.ClosingSigned messages. chanCloseMsgs chan *closeMsg // remoteFeatures is the feature vector received from the peer during // the connection handshake. remoteFeatures *lnwire.FeatureVector // resentChanSyncMsg is a set that keeps track of which channels we // have re-sent channel reestablishment messages for. This is done to // avoid getting into loop where both peers will respond to the other // peer's chansync message with its own over and over again. resentChanSyncMsg map[lnwire.ChannelID]struct{} queueQuit chan struct{} quit chan struct{} wg sync.WaitGroup } // A compile-time check to ensure that Brontide satisfies the lnpeer.Peer interface. var _ lnpeer.Peer = (*Brontide)(nil) // NewBrontide creates a new Brontide from a peer.Config struct. func NewBrontide(cfg Config) *Brontide { p := &Brontide{ cfg: cfg, activeSignal: make(chan struct{}), sendQueue: make(chan outgoingMsg), outgoingQueue: make(chan outgoingMsg), addedChannels: make(map[lnwire.ChannelID]struct{}), activeChannels: make(map[lnwire.ChannelID]*lnwallet.LightningChannel), newChannels: make(chan *newChannelMsg, 1), activeMsgStreams: make(map[lnwire.ChannelID]*msgStream), activeChanCloses: make(map[lnwire.ChannelID]*chancloser.ChanCloser), localCloseChanReqs: make(chan *htlcswitch.ChanClose), linkFailures: make(chan linkFailureReport), chanCloseMsgs: make(chan *closeMsg), resentChanSyncMsg: make(map[lnwire.ChannelID]struct{}), queueQuit: make(chan struct{}), quit: make(chan struct{}), } return p } // Start starts all helper goroutines the peer needs for normal operations. In // the case this peer has already been started, then this function is a noop. func (p *Brontide) Start() error { if atomic.AddInt32(&p.started, 1) != 1 { return nil } peerLog.Tracef("Peer %v starting", p) // Fetch and then load all the active channels we have with this remote // peer from the database. activeChans, err := p.cfg.ChannelDB.FetchOpenChannels( p.cfg.Addr.IdentityKey, ) if err != nil { peerLog.Errorf("Unable to fetch active chans "+ "for peer %v: %v", p, err) return err } if len(activeChans) == 0 { p.cfg.PrunePersistentPeerConnection(p.cfg.PubKeyBytes) } // Quickly check if we have any existing legacy channels with this // peer. haveLegacyChan := false for _, c := range activeChans { if c.ChanType.IsTweakless() { continue } haveLegacyChan = true break } // Exchange local and global features, the init message should be very // first between two nodes. if err := p.sendInitMsg(haveLegacyChan); err != nil { return fmt.Errorf("unable to send init msg: %v", err) } // Before we launch any of the helper goroutines off the peer struct, // we'll first ensure proper adherence to the p2p protocol. The init // message MUST be sent before any other message. readErr := make(chan error, 1) msgChan := make(chan lnwire.Message, 1) p.wg.Add(1) go func() { defer p.wg.Done() msg, err := p.readNextMessage() if err != nil { readErr <- err msgChan <- nil return } readErr <- nil msgChan <- msg }() select { // In order to avoid blocking indefinitely, we'll give the other peer // an upper timeout to respond before we bail out early. case <-time.After(handshakeTimeout): return fmt.Errorf("peer did not complete handshake within %v", handshakeTimeout) case err := <-readErr: if err != nil { return fmt.Errorf("unable to read init msg: %v", err) } } // Once the init message arrives, we can parse it so we can figure out // the negotiation of features for this session. msg := <-msgChan if msg, ok := msg.(*lnwire.Init); ok { if err := p.handleInitMsg(msg); err != nil { p.storeError(err) return err } } else { return errors.New("very first message between nodes " + "must be init message") } // Next, load all the active channels we have with this peer, // registering them with the switch and launching the necessary // goroutines required to operate them. peerLog.Debugf("Loaded %v active channels from database with "+ "NodeKey(%x)", len(activeChans), p.PubKey()) msgs, err := p.loadActiveChannels(activeChans) if err != nil { return fmt.Errorf("unable to load channels: %v", err) } p.startTime = time.Now() p.wg.Add(5) go p.queueHandler() go p.writeHandler() go p.readHandler() go p.channelManager() go p.pingHandler() // Signal to any external processes that the peer is now active. close(p.activeSignal) // Now that the peer has started up, we send any channel sync messages // that must be resent for borked channels. if len(msgs) > 0 { peerLog.Infof("Sending %d channel sync messages to peer after "+ "loading active channels", len(msgs)) if err := p.SendMessage(true, msgs...); err != nil { peerLog.Warnf("Failed sending channel sync "+ "messages to peer %v: %v", p, err) } } // Node announcements don't propagate very well throughout the network // as there isn't a way to efficiently query for them through their // timestamp, mostly affecting nodes that were offline during the time // of broadcast. We'll resend our node announcement to the remote peer // as a best-effort delivery such that it can also propagate to their // peers. To ensure they can successfully process it in most cases, // we'll only resend it as long as we have at least one confirmed // advertised channel with the remote peer. // // TODO(wilmer): Remove this once we're able to query for node // announcements through their timestamps. p.maybeSendNodeAnn(activeChans) return nil } // initGossipSync initializes either a gossip syncer or an initial routing // dump, depending on the negotiated synchronization method. func (p *Brontide) initGossipSync() { // If the remote peer knows of the new gossip queries feature, then // we'll create a new gossipSyncer in the AuthenticatedGossiper for it. if p.remoteFeatures.HasFeature(lnwire.GossipQueriesOptional) { peerLog.Infof("Negotiated chan series queries with %x", p.cfg.PubKeyBytes[:]) // Register the peer's gossip syncer with the gossiper. // This blocks synchronously to ensure the gossip syncer is // registered with the gossiper before attempting to read // messages from the remote peer. // // TODO(wilmer): Only sync updates from non-channel peers. This // requires an improved version of the current network // bootstrapper to ensure we can find and connect to non-channel // peers. p.cfg.AuthGossiper.InitSyncState(p) } } // QuitSignal is a method that should return a channel which will be sent upon // or closed once the backing peer exits. This allows callers using the // interface to cancel any processing in the event the backing implementation // exits. // // NOTE: Part of the lnpeer.Peer interface. func (p *Brontide) QuitSignal() <-chan struct{} { return p.quit } // loadActiveChannels creates indexes within the peer for tracking all active // channels returned by the database. It returns a slice of channel reestablish // messages that should be sent to the peer immediately, in case we have borked // channels that haven't been closed yet. func (p *Brontide) loadActiveChannels(chans []*channeldb.OpenChannel) ( []lnwire.Message, error) { // Return a slice of messages to send to the peers in case the channel // cannot be loaded normally. var msgs []lnwire.Message for _, dbChan := range chans { lnChan, err := lnwallet.NewLightningChannel( p.cfg.Signer, dbChan, p.cfg.SigPool, ) if err != nil { return nil, err } chanPoint := &dbChan.FundingOutpoint chanID := lnwire.NewChanIDFromOutPoint(chanPoint) peerLog.Infof("NodeKey(%x) loading ChannelPoint(%v)", p.PubKey(), chanPoint) // Skip adding any permanently irreconcilable channels to the // htlcswitch. if !dbChan.HasChanStatus(channeldb.ChanStatusDefault) && !dbChan.HasChanStatus(channeldb.ChanStatusRestored) { peerLog.Warnf("ChannelPoint(%v) has status %v, won't "+ "start.", chanPoint, dbChan.ChanStatus()) // To help our peer recover from a potential data loss, // we resend our channel reestablish message if the // channel is in a borked state. We won't process any // channel reestablish message sent from the peer, but // that's okay since the assumption is that we did when // marking the channel borked. chanSync, err := dbChan.ChanSyncMsg() if err != nil { peerLog.Errorf("Unable to create channel "+ "reestablish message for channel %v: "+ "%v", chanPoint, err) continue } msgs = append(msgs, chanSync) continue } // Before we register this new link with the HTLC Switch, we'll // need to fetch its current link-layer forwarding policy from // the database. graph := p.cfg.ChannelGraph info, p1, p2, err := graph.FetchChannelEdgesByOutpoint(chanPoint) if err != nil && err != channeldb.ErrEdgeNotFound { return nil, err } // We'll filter out our policy from the directional channel // edges based whom the edge connects to. If it doesn't connect // to us, then we know that we were the one that advertised the // policy. // // TODO(roasbeef): can add helper method to get policy for // particular channel. var selfPolicy *channeldb.ChannelEdgePolicy if info != nil && bytes.Equal(info.NodeKey1Bytes[:], p.cfg.ServerPubKey[:]) { selfPolicy = p1 } else { selfPolicy = p2 } // If we don't yet have an advertised routing policy, then // we'll use the current default, otherwise we'll translate the // routing policy into a forwarding policy. var forwardingPolicy *htlcswitch.ForwardingPolicy if selfPolicy != nil { forwardingPolicy = &htlcswitch.ForwardingPolicy{ MinHTLCOut: selfPolicy.MinHTLC, MaxHTLC: selfPolicy.MaxHTLC, BaseFee: selfPolicy.FeeBaseMSat, FeeRate: selfPolicy.FeeProportionalMillionths, TimeLockDelta: uint32(selfPolicy.TimeLockDelta), } } else { peerLog.Warnf("Unable to find our forwarding policy "+ "for channel %v, using default values", chanPoint) forwardingPolicy = &p.cfg.RoutingPolicy } peerLog.Tracef("Using link policy of: %v", spew.Sdump(forwardingPolicy)) // If the channel is pending, set the value to nil in the // activeChannels map. This is done to signify that the channel is // pending. We don't add the link to the switch here - it's the funding // manager's responsibility to spin up pending channels. Adding them // here would just be extra work as we'll tear them down when creating // + adding the final link. if lnChan.IsPending() { p.activeChanMtx.Lock() p.activeChannels[chanID] = nil p.activeChanMtx.Unlock() continue } // Subscribe to the set of on-chain events for this channel. chainEvents, err := p.cfg.ChainArb.SubscribeChannelEvents( *chanPoint, ) if err != nil { return nil, err } err = p.addLink( chanPoint, lnChan, forwardingPolicy, chainEvents, true, ) if err != nil { return nil, fmt.Errorf("unable to add link %v to "+ "switch: %v", chanPoint, err) } p.activeChanMtx.Lock() p.activeChannels[chanID] = lnChan p.activeChanMtx.Unlock() } return msgs, nil } // addLink creates and adds a new ChannelLink from the specified channel. func (p *Brontide) addLink(chanPoint *wire.OutPoint, lnChan *lnwallet.LightningChannel, forwardingPolicy *htlcswitch.ForwardingPolicy, chainEvents *contractcourt.ChainEventSubscription, syncStates bool) error { // onChannelFailure will be called by the link in case the channel // fails for some reason. onChannelFailure := func(chanID lnwire.ChannelID, shortChanID lnwire.ShortChannelID, linkErr htlcswitch.LinkFailureError) { failure := linkFailureReport{ chanPoint: *chanPoint, chanID: chanID, shortChanID: shortChanID, linkErr: linkErr, } select { case p.linkFailures <- failure: case <-p.quit: case <-p.cfg.Quit: } } updateContractSignals := func(signals *contractcourt.ContractSignals) error { return p.cfg.ChainArb.UpdateContractSignals(*chanPoint, signals) } chanType := lnChan.State().ChanType // Select the appropriate tower client based on the channel type. It's // okay if the clients are disabled altogether and these values are nil, // as the link will check for nilness before using either. var towerClient htlcswitch.TowerClient if chanType.HasAnchors() { towerClient = p.cfg.AnchorTowerClient } else { towerClient = p.cfg.TowerClient } linkCfg := htlcswitch.ChannelLinkConfig{ Peer: p, DecodeHopIterators: p.cfg.Sphinx.DecodeHopIterators, ExtractErrorEncrypter: p.cfg.Sphinx.ExtractErrorEncrypter, FetchLastChannelUpdate: p.cfg.FetchLastChanUpdate, HodlMask: p.cfg.Hodl.Mask(), Registry: p.cfg.Invoices, Switch: p.cfg.Switch, Circuits: p.cfg.Switch.CircuitModifier(), ForwardPackets: p.cfg.InterceptSwitch.ForwardPackets, FwrdingPolicy: *forwardingPolicy, FeeEstimator: p.cfg.FeeEstimator, PreimageCache: p.cfg.WitnessBeacon, ChainEvents: chainEvents, UpdateContractSignals: updateContractSignals, OnChannelFailure: onChannelFailure, SyncStates: syncStates, BatchTicker: ticker.New(50 * time.Millisecond), FwdPkgGCTicker: ticker.New(time.Hour), PendingCommitTicker: ticker.New(time.Minute), BatchSize: 10, UnsafeReplay: p.cfg.UnsafeReplay, MinFeeUpdateTimeout: htlcswitch.DefaultMinLinkFeeUpdateTimeout, MaxFeeUpdateTimeout: htlcswitch.DefaultMaxLinkFeeUpdateTimeout, OutgoingCltvRejectDelta: p.cfg.OutgoingCltvRejectDelta, TowerClient: towerClient, MaxOutgoingCltvExpiry: p.cfg.MaxOutgoingCltvExpiry, MaxFeeAllocation: p.cfg.MaxChannelFeeAllocation, NotifyActiveLink: p.cfg.ChannelNotifier.NotifyActiveLinkEvent, NotifyActiveChannel: p.cfg.ChannelNotifier.NotifyActiveChannelEvent, NotifyInactiveChannel: p.cfg.ChannelNotifier.NotifyInactiveChannelEvent, HtlcNotifier: p.cfg.HtlcNotifier, } link := htlcswitch.NewChannelLink(linkCfg, lnChan) // Before adding our new link, purge the switch of any pending or live // links going by the same channel id. If one is found, we'll shut it // down to ensure that the mailboxes are only ever under the control of // one link. p.cfg.Switch.RemoveLink(link.ChanID()) // With the channel link created, we'll now notify the htlc switch so // this channel can be used to dispatch local payments and also // passively forward payments. return p.cfg.Switch.AddLink(link) } // maybeSendNodeAnn sends our node announcement to the remote peer if at least // one confirmed public channel exists with them. func (p *Brontide) maybeSendNodeAnn(channels []*channeldb.OpenChannel) { hasConfirmedPublicChan := false for _, channel := range channels { if channel.IsPending { continue } if channel.ChannelFlags&lnwire.FFAnnounceChannel == 0 { continue } hasConfirmedPublicChan = true break } if !hasConfirmedPublicChan { return } ourNodeAnn, err := p.cfg.GenNodeAnnouncement(false) if err != nil { peerLog.Debugf("Unable to retrieve node announcement: %v", err) return } if err := p.SendMessageLazy(false, &ourNodeAnn); err != nil { peerLog.Debugf("Unable to resend node announcement to %x: %v", p.cfg.PubKeyBytes, err) } } // WaitForDisconnect waits until the peer has disconnected. A peer may be // disconnected if the local or remote side terminates the connection, or an // irrecoverable protocol error has been encountered. This method will only // begin watching the peer's waitgroup after the ready channel or the peer's // quit channel are signaled. The ready channel should only be signaled if a // call to Start returns no error. Otherwise, if the peer fails to start, // calling Disconnect will signal the quit channel and the method will not // block, since no goroutines were spawned. func (p *Brontide) WaitForDisconnect(ready chan struct{}) { select { case <-ready: case <-p.quit: } p.wg.Wait() } // Disconnect terminates the connection with the remote peer. Additionally, a // signal is sent to the server and htlcSwitch indicating the resources // allocated to the peer can now be cleaned up. func (p *Brontide) Disconnect(reason error) { if !atomic.CompareAndSwapInt32(&p.disconnect, 0, 1) { return } err := fmt.Errorf("disconnecting %s, reason: %v", p, reason) p.storeError(err) peerLog.Infof(err.Error()) // Ensure that the TCP connection is properly closed before continuing. p.cfg.Conn.Close() close(p.quit) } // String returns the string representation of this peer. func (p *Brontide) String() string { return fmt.Sprintf("%x@%s", p.cfg.PubKeyBytes, p.cfg.Conn.RemoteAddr()) } // readNextMessage reads, and returns the next message on the wire along with // any additional raw payload. func (p *Brontide) readNextMessage() (lnwire.Message, error) { noiseConn := p.cfg.Conn err := noiseConn.SetReadDeadline(time.Time{}) if err != nil { return nil, err } pktLen, err := noiseConn.ReadNextHeader() if err != nil { return nil, err } // First we'll read the next _full_ message. We do this rather than // reading incrementally from the stream as the Lightning wire protocol // is message oriented and allows nodes to pad on additional data to // the message stream. var rawMsg []byte err = p.cfg.ReadPool.Submit(func(buf *buffer.Read) error { // Before reading the body of the message, set the read timeout // accordingly to ensure we don't block other readers using the // pool. We do so only after the task has been scheduled to // ensure the deadline doesn't expire while the message is in // the process of being scheduled. readDeadline := time.Now().Add(readMessageTimeout) readErr := noiseConn.SetReadDeadline(readDeadline) if readErr != nil { return readErr } rawMsg, readErr = noiseConn.ReadNextBody(buf[:pktLen]) return readErr }) atomic.AddUint64(&p.bytesReceived, uint64(len(rawMsg))) if err != nil { return nil, err } // Next, create a new io.Reader implementation from the raw message, // and use this to decode the message directly from. msgReader := bytes.NewReader(rawMsg) nextMsg, err := lnwire.ReadMessage(msgReader, 0) if err != nil { return nil, err } p.logWireMessage(nextMsg, true) return nextMsg, nil } // msgStream implements a goroutine-safe, in-order stream of messages to be // delivered via closure to a receiver. These messages MUST be in order due to // the nature of the lightning channel commitment and gossiper state machines. // TODO(conner): use stream handler interface to abstract out stream // state/logging type msgStream struct { streamShutdown int32 // To be used atomically. peer *Brontide apply func(lnwire.Message) startMsg string stopMsg string msgCond *sync.Cond msgs []lnwire.Message mtx sync.Mutex producerSema chan struct{} wg sync.WaitGroup quit chan struct{} } // newMsgStream creates a new instance of a chanMsgStream for a particular // channel identified by its channel ID. bufSize is the max number of messages // that should be buffered in the internal queue. Callers should set this to a // sane value that avoids blocking unnecessarily, but doesn't allow an // unbounded amount of memory to be allocated to buffer incoming messages. func newMsgStream(p *Brontide, startMsg, stopMsg string, bufSize uint32, apply func(lnwire.Message)) *msgStream { stream := &msgStream{ peer: p, apply: apply, startMsg: startMsg, stopMsg: stopMsg, producerSema: make(chan struct{}, bufSize), quit: make(chan struct{}), } stream.msgCond = sync.NewCond(&stream.mtx) // Before we return the active stream, we'll populate the producer's // semaphore channel. We'll use this to ensure that the producer won't // attempt to allocate memory in the queue for an item until it has // sufficient extra space. for i := uint32(0); i < bufSize; i++ { stream.producerSema <- struct{}{} } return stream } // Start starts the chanMsgStream. func (ms *msgStream) Start() { ms.wg.Add(1) go ms.msgConsumer() } // Stop stops the chanMsgStream. func (ms *msgStream) Stop() { // TODO(roasbeef): signal too? close(ms.quit) // Now that we've closed the channel, we'll repeatedly signal the msg // consumer until we've detected that it has exited. for atomic.LoadInt32(&ms.streamShutdown) == 0 { ms.msgCond.Signal() time.Sleep(time.Millisecond * 100) } ms.wg.Wait() } // msgConsumer is the main goroutine that streams messages from the peer's // readHandler directly to the target channel. func (ms *msgStream) msgConsumer() { defer ms.wg.Done() defer peerLog.Tracef(ms.stopMsg) defer atomic.StoreInt32(&ms.streamShutdown, 1) peerLog.Tracef(ms.startMsg) for { // First, we'll check our condition. If the queue of messages // is empty, then we'll wait until a new item is added. ms.msgCond.L.Lock() for len(ms.msgs) == 0 { ms.msgCond.Wait() // If we woke up in order to exit, then we'll do so. // Otherwise, we'll check the message queue for any new // items. select { case <-ms.peer.quit: ms.msgCond.L.Unlock() return case <-ms.quit: ms.msgCond.L.Unlock() return default: } } // Grab the message off the front of the queue, shifting the // slice's reference down one in order to remove the message // from the queue. msg := ms.msgs[0] ms.msgs[0] = nil // Set to nil to prevent GC leak. ms.msgs = ms.msgs[1:] ms.msgCond.L.Unlock() ms.apply(msg) // We've just successfully processed an item, so we'll signal // to the producer that a new slot in the buffer. We'll use // this to bound the size of the buffer to avoid allowing it to // grow indefinitely. select { case ms.producerSema <- struct{}{}: case <-ms.peer.quit: return case <-ms.quit: return } } } // AddMsg adds a new message to the msgStream. This function is safe for // concurrent access. func (ms *msgStream) AddMsg(msg lnwire.Message) { // First, we'll attempt to receive from the producerSema struct. This // acts as a sempahore to prevent us from indefinitely buffering // incoming items from the wire. Either the msg queue isn't full, and // we'll not block, or the queue is full, and we'll block until either // we're signalled to quit, or a slot is freed up. select { case <-ms.producerSema: case <-ms.peer.quit: return case <-ms.quit: return } // Next, we'll lock the condition, and add the message to the end of // the message queue. ms.msgCond.L.Lock() ms.msgs = append(ms.msgs, msg) ms.msgCond.L.Unlock() // With the message added, we signal to the msgConsumer that there are // additional messages to consume. ms.msgCond.Signal() } // waitUntilLinkActive waits until the target link is active and returns a // ChannelLink to pass messages to. It accomplishes this by subscribing to // an ActiveLinkEvent which is emitted by the link when it first starts up. func waitUntilLinkActive(p *Brontide, cid lnwire.ChannelID) htlcswitch.ChannelLink { // Subscribe to receive channel events. // // NOTE: If the link is already active by SubscribeChannelEvents, then // GetLink will retrieve the link and we can send messages. If the link // becomes active between SubscribeChannelEvents and GetLink, then GetLink // will retrieve the link. If the link becomes active after GetLink, then // we will get an ActiveLinkEvent notification and retrieve the link. If // the call to GetLink is before SubscribeChannelEvents, however, there // will be a race condition. sub, err := p.cfg.ChannelNotifier.SubscribeChannelEvents() if err != nil { // If we have a non-nil error, then the server is shutting down and we // can exit here and return nil. This means no message will be delivered // to the link. return nil } defer sub.Cancel() // The link may already be active by this point, and we may have missed the // ActiveLinkEvent. Check if the link exists. link, _ := p.cfg.Switch.GetLink(cid) if link != nil { return link } // If the link is nil, we must wait for it to be active. for { select { // A new event has been sent by the ChannelNotifier. We first check // whether the event is an ActiveLinkEvent. If it is, we'll check // that the event is for this channel. Otherwise, we discard the // message. case e := <-sub.Updates(): event, ok := e.(channelnotifier.ActiveLinkEvent) if !ok { // Ignore this notification. continue } chanPoint := event.ChannelPoint // Check whether the retrieved chanPoint matches the target // channel id. if !cid.IsChanPoint(chanPoint) { continue } // The link shouldn't be nil as we received an // ActiveLinkEvent. If it is nil, we return nil and the // calling function should catch it. link, _ = p.cfg.Switch.GetLink(cid) return link case <-p.quit: return nil } } } // newChanMsgStream is used to create a msgStream between the peer and // particular channel link in the htlcswitch. We utilize additional // synchronization with the fundingManager to ensure we don't attempt to // dispatch a message to a channel before it is fully active. A reference to the // channel this stream forwards to is held in scope to prevent unnecessary // lookups. func newChanMsgStream(p *Brontide, cid lnwire.ChannelID) *msgStream { var chanLink htlcswitch.ChannelLink apply := func(msg lnwire.Message) { // This check is fine because if the link no longer exists, it will // be removed from the activeChannels map and subsequent messages // shouldn't reach the chan msg stream. if chanLink == nil { chanLink = waitUntilLinkActive(p, cid) // If the link is still not active and the calling function // errored out, just return. if chanLink == nil { return } } // In order to avoid unnecessarily delivering message // as the peer is exiting, we'll check quickly to see // if we need to exit. select { case <-p.quit: return default: } chanLink.HandleChannelUpdate(msg) } return newMsgStream(p, fmt.Sprintf("Update stream for ChannelID(%x) created", cid[:]), fmt.Sprintf("Update stream for ChannelID(%x) exiting", cid[:]), 1000, apply, ) } // newDiscMsgStream is used to setup a msgStream between the peer and the // authenticated gossiper. This stream should be used to forward all remote // channel announcements. func newDiscMsgStream(p *Brontide) *msgStream { apply := func(msg lnwire.Message) { p.cfg.AuthGossiper.ProcessRemoteAnnouncement(msg, p) } return newMsgStream( p, "Update stream for gossiper created", "Update stream for gossiper exited", 1000, apply, ) } // readHandler is responsible for reading messages off the wire in series, then // properly dispatching the handling of the message to the proper subsystem. // // NOTE: This method MUST be run as a goroutine. func (p *Brontide) readHandler() { defer p.wg.Done() // We'll stop the timer after a new messages is received, and also // reset it after we process the next message. idleTimer := time.AfterFunc(idleTimeout, func() { err := fmt.Errorf("peer %s no answer for %s -- disconnecting", p, idleTimeout) p.Disconnect(err) }) // Initialize our negotiated gossip sync method before reading messages // off the wire. When using gossip queries, this ensures a gossip // syncer is active by the time query messages arrive. // // TODO(conner): have peer store gossip syncer directly and bypass // gossiper? p.initGossipSync() discStream := newDiscMsgStream(p) discStream.Start() defer discStream.Stop() out: for atomic.LoadInt32(&p.disconnect) == 0 { nextMsg, err := p.readNextMessage() if !idleTimer.Stop() { select { case <-idleTimer.C: default: } } if err != nil { peerLog.Infof("unable to read message from %v: %v", p, err) // If we could not read our peer's message due to an // unknown type or invalid alias, we continue processing // as normal. We store unknown message and address // types, as they may provide debugging insight. switch e := err.(type) { // If this is just a message we don't yet recognize, // we'll continue processing as normal as this allows // us to introduce new messages in a forwards // compatible manner. case *lnwire.UnknownMessage: p.storeError(e) idleTimer.Reset(idleTimeout) continue // If they sent us an address type that we don't yet // know of, then this isn't a wire error, so we'll // simply continue parsing the remainder of their // messages. case *lnwire.ErrUnknownAddrType: p.storeError(e) idleTimer.Reset(idleTimeout) continue // If the NodeAnnouncement has an invalid alias, then // we'll log that error above and continue so we can // continue to read messages from the peer. We do not // store this error because it is of little debugging // value. case *lnwire.ErrInvalidNodeAlias: idleTimer.Reset(idleTimeout) continue // If the error we encountered wasn't just a message we // didn't recognize, then we'll stop all processing as // this is a fatal error. default: break out } } var ( targetChan lnwire.ChannelID isLinkUpdate bool ) switch msg := nextMsg.(type) { case *lnwire.Pong: // When we receive a Pong message in response to our // last ping message, we'll use the time in which we // sent the ping message to measure a rough estimate of // round trip time. pingSendTime := atomic.LoadInt64(&p.pingLastSend) delay := (time.Now().UnixNano() - pingSendTime) / 1000 atomic.StoreInt64(&p.pingTime, delay) case *lnwire.Ping: pongBytes := make([]byte, msg.NumPongBytes) p.queueMsg(lnwire.NewPong(pongBytes), nil) case *lnwire.OpenChannel, *lnwire.AcceptChannel, *lnwire.FundingCreated, *lnwire.FundingSigned, *lnwire.FundingLocked: p.cfg.FundingManager.ProcessFundingMsg(msg, p) case *lnwire.Shutdown: select { case p.chanCloseMsgs <- &closeMsg{msg.ChannelID, msg}: case <-p.quit: break out } case *lnwire.ClosingSigned: select { case p.chanCloseMsgs <- &closeMsg{msg.ChannelID, msg}: case <-p.quit: break out } case *lnwire.Error: targetChan = msg.ChanID isLinkUpdate = p.handleError(msg) case *lnwire.ChannelReestablish: targetChan = msg.ChanID isLinkUpdate = p.isActiveChannel(targetChan) // If we failed to find the link in question, and the // message received was a channel sync message, then // this might be a peer trying to resync closed channel. // In this case we'll try to resend our last channel // sync message, such that the peer can recover funds // from the closed channel. if !isLinkUpdate { err := p.resendChanSyncMsg(targetChan) if err != nil { // TODO(halseth): send error to peer? peerLog.Errorf("resend failed: %v", err) } } case LinkUpdater: targetChan = msg.TargetChanID() isLinkUpdate = p.isActiveChannel(targetChan) case *lnwire.ChannelUpdate, *lnwire.ChannelAnnouncement, *lnwire.NodeAnnouncement, *lnwire.AnnounceSignatures, *lnwire.GossipTimestampRange, *lnwire.QueryShortChanIDs, *lnwire.QueryChannelRange, *lnwire.ReplyChannelRange, *lnwire.ReplyShortChanIDsEnd: discStream.AddMsg(msg) default: // If the message we received is unknown to us, store // the type to track the failure. err := fmt.Errorf("unknown message type %v received", uint16(msg.MsgType())) p.storeError(err) peerLog.Errorf("peer: %v, %v", p, err) } if isLinkUpdate { // If this is a channel update, then we need to feed it // into the channel's in-order message stream. chanStream, ok := p.activeMsgStreams[targetChan] if !ok { // If a stream hasn't yet been created, then // we'll do so, add it to the map, and finally // start it. chanStream = newChanMsgStream(p, targetChan) p.activeMsgStreams[targetChan] = chanStream chanStream.Start() defer chanStream.Stop() } // With the stream obtained, add the message to the // stream so we can continue processing message. chanStream.AddMsg(nextMsg) } idleTimer.Reset(idleTimeout) } p.Disconnect(errors.New("read handler closed")) peerLog.Tracef("readHandler for peer %v done", p) } // isActiveChannel returns true if the provided channel id is active, otherwise // returns false. func (p *Brontide) isActiveChannel(chanID lnwire.ChannelID) bool { p.activeChanMtx.RLock() _, ok := p.activeChannels[chanID] p.activeChanMtx.RUnlock() return ok } // storeError stores an error in our peer's buffer of recent errors with the // current timestamp. Errors are only stored if we have at least one active // channel with the peer to mitigate a dos vector where a peer costlessly // connects to us and spams us with errors. func (p *Brontide) storeError(err error) { var haveChannels bool p.activeChanMtx.RLock() for _, channel := range p.activeChannels { // Pending channels will be nil in the activeChannels map. if channel == nil { continue } haveChannels = true break } p.activeChanMtx.RUnlock() // If we do not have any active channels with the peer, we do not store // errors as a dos mitigation. if !haveChannels { peerLog.Tracef("no channels with peer: %v, not storing err", p) return } p.cfg.ErrorBuffer.Add( &TimestampedError{Timestamp: time.Now(), Error: err}, ) } // handleError processes an error message read from the remote peer. The boolean // returns indicates whether the message should be delivered to a targeted peer. // It stores the error we received from the peer in memory if we have a channel // open with the peer. // // NOTE: This method should only be called from within the readHandler. func (p *Brontide) handleError(msg *lnwire.Error) bool { // Store the error we have received. p.storeError(msg) switch { // In the case of an all-zero channel ID we want to forward the error to // all channels with this peer. case msg.ChanID == lnwire.ConnectionWideID: for _, chanStream := range p.activeMsgStreams { chanStream.AddMsg(msg) } return false // If the channel ID for the error message corresponds to a pending // channel, then the funding manager will handle the error. case p.cfg.FundingManager.IsPendingChannel(msg.ChanID, p): p.cfg.FundingManager.ProcessFundingMsg(msg, p) return false // If not we hand the error to the channel link for this channel. case p.isActiveChannel(msg.ChanID): return true default: return false } } // messageSummary returns a human-readable string that summarizes a // incoming/outgoing message. Not all messages will have a summary, only those // which have additional data that can be informative at a glance. func messageSummary(msg lnwire.Message) string { switch msg := msg.(type) { case *lnwire.Init: // No summary. return "" case *lnwire.OpenChannel: return fmt.Sprintf("temp_chan_id=%x, chain=%v, csv=%v, amt=%v, "+ "push_amt=%v, reserve=%v, flags=%v", msg.PendingChannelID[:], msg.ChainHash, msg.CsvDelay, msg.FundingAmount, msg.PushAmount, msg.ChannelReserve, msg.ChannelFlags) case *lnwire.AcceptChannel: return fmt.Sprintf("temp_chan_id=%x, reserve=%v, csv=%v, num_confs=%v", msg.PendingChannelID[:], msg.ChannelReserve, msg.CsvDelay, msg.MinAcceptDepth) case *lnwire.FundingCreated: return fmt.Sprintf("temp_chan_id=%x, chan_point=%v", msg.PendingChannelID[:], msg.FundingPoint) case *lnwire.FundingSigned: return fmt.Sprintf("chan_id=%v", msg.ChanID) case *lnwire.FundingLocked: return fmt.Sprintf("chan_id=%v, next_point=%x", msg.ChanID, msg.NextPerCommitmentPoint.SerializeCompressed()) case *lnwire.Shutdown: return fmt.Sprintf("chan_id=%v, script=%x", msg.ChannelID, msg.Address[:]) case *lnwire.ClosingSigned: return fmt.Sprintf("chan_id=%v, fee_sat=%v", msg.ChannelID, msg.FeeSatoshis) case *lnwire.UpdateAddHTLC: return fmt.Sprintf("chan_id=%v, id=%v, amt=%v, expiry=%v, hash=%x", msg.ChanID, msg.ID, msg.Amount, msg.Expiry, msg.PaymentHash[:]) case *lnwire.UpdateFailHTLC: return fmt.Sprintf("chan_id=%v, id=%v, reason=%x", msg.ChanID, msg.ID, msg.Reason) case *lnwire.UpdateFulfillHTLC: return fmt.Sprintf("chan_id=%v, id=%v, pre_image=%x", msg.ChanID, msg.ID, msg.PaymentPreimage[:]) case *lnwire.CommitSig: return fmt.Sprintf("chan_id=%v, num_htlcs=%v", msg.ChanID, len(msg.HtlcSigs)) case *lnwire.RevokeAndAck: return fmt.Sprintf("chan_id=%v, rev=%x, next_point=%x", msg.ChanID, msg.Revocation[:], msg.NextRevocationKey.SerializeCompressed()) case *lnwire.UpdateFailMalformedHTLC: return fmt.Sprintf("chan_id=%v, id=%v, fail_code=%v", msg.ChanID, msg.ID, msg.FailureCode) case *lnwire.Error: return fmt.Sprintf("%v", msg.Error()) case *lnwire.AnnounceSignatures: return fmt.Sprintf("chan_id=%v, short_chan_id=%v", msg.ChannelID, msg.ShortChannelID.ToUint64()) case *lnwire.ChannelAnnouncement: return fmt.Sprintf("chain_hash=%v, short_chan_id=%v", msg.ChainHash, msg.ShortChannelID.ToUint64()) case *lnwire.ChannelUpdate: return fmt.Sprintf("chain_hash=%v, short_chan_id=%v, "+ "mflags=%v, cflags=%v, update_time=%v", msg.ChainHash, msg.ShortChannelID.ToUint64(), msg.MessageFlags, msg.ChannelFlags, time.Unix(int64(msg.Timestamp), 0)) case *lnwire.NodeAnnouncement: return fmt.Sprintf("node=%x, update_time=%v", msg.NodeID, time.Unix(int64(msg.Timestamp), 0)) case *lnwire.Ping: // No summary. return "" case *lnwire.Pong: // No summary. return "" case *lnwire.UpdateFee: return fmt.Sprintf("chan_id=%v, fee_update_sat=%v", msg.ChanID, int64(msg.FeePerKw)) case *lnwire.ChannelReestablish: return fmt.Sprintf("next_local_height=%v, remote_tail_height=%v", msg.NextLocalCommitHeight, msg.RemoteCommitTailHeight) case *lnwire.ReplyShortChanIDsEnd: return fmt.Sprintf("chain_hash=%v, complete=%v", msg.ChainHash, msg.Complete) case *lnwire.ReplyChannelRange: return fmt.Sprintf("start_height=%v, end_height=%v, "+ "num_chans=%v, encoding=%v", msg.FirstBlockHeight, msg.LastBlockHeight(), len(msg.ShortChanIDs), msg.EncodingType) case *lnwire.QueryShortChanIDs: return fmt.Sprintf("chain_hash=%v, encoding=%v, num_chans=%v", msg.ChainHash, msg.EncodingType, len(msg.ShortChanIDs)) case *lnwire.QueryChannelRange: return fmt.Sprintf("chain_hash=%v, start_height=%v, "+ "end_height=%v", msg.ChainHash, msg.FirstBlockHeight, msg.LastBlockHeight()) case *lnwire.GossipTimestampRange: return fmt.Sprintf("chain_hash=%v, first_stamp=%v, "+ "stamp_range=%v", msg.ChainHash, time.Unix(int64(msg.FirstTimestamp), 0), msg.TimestampRange) } return "" } // logWireMessage logs the receipt or sending of particular wire message. This // function is used rather than just logging the message in order to produce // less spammy log messages in trace mode by setting the 'Curve" parameter to // nil. Doing this avoids printing out each of the field elements in the curve // parameters for secp256k1. func (p *Brontide) logWireMessage(msg lnwire.Message, read bool) { summaryPrefix := "Received" if !read { summaryPrefix = "Sending" } peerLog.Debugf("%v", newLogClosure(func() string { // Debug summary of message. summary := messageSummary(msg) if len(summary) > 0 { summary = "(" + summary + ")" } preposition := "to" if read { preposition = "from" } return fmt.Sprintf("%v %v%s %v %s", summaryPrefix, msg.MsgType(), summary, preposition, p) })) switch m := msg.(type) { case *lnwire.ChannelReestablish: if m.LocalUnrevokedCommitPoint != nil { m.LocalUnrevokedCommitPoint.Curve = nil } case *lnwire.RevokeAndAck: m.NextRevocationKey.Curve = nil case *lnwire.AcceptChannel: m.FundingKey.Curve = nil m.RevocationPoint.Curve = nil m.PaymentPoint.Curve = nil m.DelayedPaymentPoint.Curve = nil m.HtlcPoint.Curve = nil m.FirstCommitmentPoint.Curve = nil case *lnwire.OpenChannel: m.FundingKey.Curve = nil m.RevocationPoint.Curve = nil m.PaymentPoint.Curve = nil m.DelayedPaymentPoint.Curve = nil m.HtlcPoint.Curve = nil m.FirstCommitmentPoint.Curve = nil case *lnwire.FundingLocked: m.NextPerCommitmentPoint.Curve = nil } prefix := "readMessage from" if !read { prefix = "writeMessage to" } peerLog.Tracef(prefix+" %v: %v", p, newLogClosure(func() string { return spew.Sdump(msg) })) } // writeMessage writes and flushes the target lnwire.Message to the remote peer. // If the passed message is nil, this method will only try to flush an existing // message buffered on the connection. It is safe to call this method again // with a nil message iff a timeout error is returned. This will continue to // flush the pending message to the wire. func (p *Brontide) writeMessage(msg lnwire.Message) error { // Simply exit if we're shutting down. if atomic.LoadInt32(&p.disconnect) != 0 { return lnpeer.ErrPeerExiting } // Only log the message on the first attempt. if msg != nil { p.logWireMessage(msg, false) } noiseConn := p.cfg.Conn flushMsg := func() error { // Ensure the write deadline is set before we attempt to send // the message. writeDeadline := time.Now().Add(writeMessageTimeout) err := noiseConn.SetWriteDeadline(writeDeadline) if err != nil { return err } // Flush the pending message to the wire. If an error is // encountered, e.g. write timeout, the number of bytes written // so far will be returned. n, err := noiseConn.Flush() // Record the number of bytes written on the wire, if any. if n > 0 { atomic.AddUint64(&p.bytesSent, uint64(n)) } return err } // If the current message has already been serialized, encrypted, and // buffered on the underlying connection we will skip straight to // flushing it to the wire. if msg == nil { return flushMsg() } // Otherwise, this is a new message. We'll acquire a write buffer to // serialize the message and buffer the ciphertext on the connection. err := p.cfg.WritePool.Submit(func(buf *bytes.Buffer) error { // Using a buffer allocated by the write pool, encode the // message directly into the buffer. _, writeErr := lnwire.WriteMessage(buf, msg, 0) if writeErr != nil { return writeErr } // Finally, write the message itself in a single swoop. This // will buffer the ciphertext on the underlying connection. We // will defer flushing the message until the write pool has been // released. return noiseConn.WriteMessage(buf.Bytes()) }) if err != nil { return err } return flushMsg() } // writeHandler is a goroutine dedicated to reading messages off of an incoming // queue, and writing them out to the wire. This goroutine coordinates with the // queueHandler in order to ensure the incoming message queue is quickly // drained. // // NOTE: This method MUST be run as a goroutine. func (p *Brontide) writeHandler() { // We'll stop the timer after a new messages is sent, and also reset it // after we process the next message. idleTimer := time.AfterFunc(idleTimeout, func() { err := fmt.Errorf("peer %s no write for %s -- disconnecting", p, idleTimeout) p.Disconnect(err) }) var exitErr error out: for { select { case outMsg := <-p.sendQueue: // If we're about to send a ping message, then log the // exact time in which we send the message so we can // use the delay as a rough estimate of latency to the // remote peer. if _, ok := outMsg.msg.(*lnwire.Ping); ok { // TODO(roasbeef): do this before the write? // possibly account for processing within func? now := time.Now().UnixNano() atomic.StoreInt64(&p.pingLastSend, now) } // Record the time at which we first attempt to send the // message. startTime := time.Now() retry: // Write out the message to the socket. If a timeout // error is encountered, we will catch this and retry // after backing off in case the remote peer is just // slow to process messages from the wire. err := p.writeMessage(outMsg.msg) if nerr, ok := err.(net.Error); ok && nerr.Timeout() { peerLog.Debugf("Write timeout detected for "+ "peer %s, first write for message "+ "attempted %v ago", p, time.Since(startTime)) // If we received a timeout error, this implies // that the message was buffered on the // connection successfully and that a flush was // attempted. We'll set the message to nil so // that on a subsequent pass we only try to // flush the buffered message, and forgo // reserializing or reencrypting it. outMsg.msg = nil goto retry } // The write succeeded, reset the idle timer to prevent // us from disconnecting the peer. if !idleTimer.Stop() { select { case <-idleTimer.C: default: } } idleTimer.Reset(idleTimeout) // If the peer requested a synchronous write, respond // with the error. if outMsg.errChan != nil { outMsg.errChan <- err } if err != nil { exitErr = fmt.Errorf("unable to write "+ "message: %v", err) break out } case <-p.quit: exitErr = lnpeer.ErrPeerExiting break out } } // Avoid an exit deadlock by ensuring WaitGroups are decremented before // disconnect. p.wg.Done() p.Disconnect(exitErr) peerLog.Tracef("writeHandler for peer %v done", p) } // queueHandler is responsible for accepting messages from outside subsystems // to be eventually sent out on the wire by the writeHandler. // // NOTE: This method MUST be run as a goroutine. func (p *Brontide) queueHandler() { defer p.wg.Done() // priorityMsgs holds an in order list of messages deemed high-priority // to be added to the sendQueue. This predominately includes messages // from the funding manager and htlcswitch. priorityMsgs := list.New() // lazyMsgs holds an in order list of messages deemed low-priority to be // added to the sendQueue only after all high-priority messages have // been queued. This predominately includes messages from the gossiper. lazyMsgs := list.New() for { // Examine the front of the priority queue, if it is empty check // the low priority queue. elem := priorityMsgs.Front() if elem == nil { elem = lazyMsgs.Front() } if elem != nil { front := elem.Value.(outgoingMsg) // There's an element on the queue, try adding // it to the sendQueue. We also watch for // messages on the outgoingQueue, in case the // writeHandler cannot accept messages on the // sendQueue. select { case p.sendQueue <- front: if front.priority { priorityMsgs.Remove(elem) } else { lazyMsgs.Remove(elem) } case msg := <-p.outgoingQueue: if msg.priority { priorityMsgs.PushBack(msg) } else { lazyMsgs.PushBack(msg) } case <-p.quit: return } } else { // If there weren't any messages to send to the // writeHandler, then we'll accept a new message // into the queue from outside sub-systems. select { case msg := <-p.outgoingQueue: if msg.priority { priorityMsgs.PushBack(msg) } else { lazyMsgs.PushBack(msg) } case <-p.quit: return } } } } // pingHandler is responsible for periodically sending ping messages to the // remote peer in order to keep the connection alive and/or determine if the // connection is still active. // // NOTE: This method MUST be run as a goroutine. func (p *Brontide) pingHandler() { defer p.wg.Done() pingTicker := time.NewTicker(pingInterval) defer pingTicker.Stop() // TODO(roasbeef): make dynamic in order to create fake cover traffic const numPingBytes = 16 out: for { select { case <-pingTicker.C: p.queueMsg(lnwire.NewPing(numPingBytes), nil) case <-p.quit: break out } } } // PingTime returns the estimated ping time to the peer in microseconds. func (p *Brontide) PingTime() int64 { return atomic.LoadInt64(&p.pingTime) } // queueMsg adds the lnwire.Message to the back of the high priority send queue. // If the errChan is non-nil, an error is sent back if the msg failed to queue // or failed to write, and nil otherwise. func (p *Brontide) queueMsg(msg lnwire.Message, errChan chan error) { p.queue(true, msg, errChan) } // queueMsgLazy adds the lnwire.Message to the back of the low priority send // queue. If the errChan is non-nil, an error is sent back if the msg failed to // queue or failed to write, and nil otherwise. func (p *Brontide) queueMsgLazy(msg lnwire.Message, errChan chan error) { p.queue(false, msg, errChan) } // queue sends a given message to the queueHandler using the passed priority. If // the errChan is non-nil, an error is sent back if the msg failed to queue or // failed to write, and nil otherwise. func (p *Brontide) queue(priority bool, msg lnwire.Message, errChan chan error) { select { case p.outgoingQueue <- outgoingMsg{priority, msg, errChan}: case <-p.quit: peerLog.Tracef("Peer shutting down, could not enqueue msg: %v.", spew.Sdump(msg)) if errChan != nil { errChan <- lnpeer.ErrPeerExiting } } } // ChannelSnapshots returns a slice of channel snapshots detailing all // currently active channels maintained with the remote peer. func (p *Brontide) ChannelSnapshots() []*channeldb.ChannelSnapshot { p.activeChanMtx.RLock() defer p.activeChanMtx.RUnlock() snapshots := make([]*channeldb.ChannelSnapshot, 0, len(p.activeChannels)) for _, activeChan := range p.activeChannels { // If the activeChan is nil, then we skip it as the channel is pending. if activeChan == nil { continue } // We'll only return a snapshot for channels that are // *immedately* available for routing payments over. if activeChan.RemoteNextRevocation() == nil { continue } snapshot := activeChan.StateSnapshot() snapshots = append(snapshots, snapshot) } return snapshots } // genDeliveryScript returns a new script to be used to send our funds to in // the case of a cooperative channel close negotiation. func (p *Brontide) genDeliveryScript() ([]byte, error) { deliveryAddr, err := p.cfg.Wallet.NewAddress( lnwallet.WitnessPubKey, false, ) if err != nil { return nil, err } peerLog.Infof("Delivery addr for channel close: %v", deliveryAddr) return txscript.PayToAddrScript(deliveryAddr) } // channelManager is goroutine dedicated to handling all requests/signals // pertaining to the opening, cooperative closing, and force closing of all // channels maintained with the remote peer. // // NOTE: This method MUST be run as a goroutine. func (p *Brontide) channelManager() { defer p.wg.Done() // reenableTimeout will fire once after the configured channel status // interval has elapsed. This will trigger us to sign new channel // updates and broadcast them with the "disabled" flag unset. reenableTimeout := time.After(p.cfg.ChanActiveTimeout) out: for { select { // A new channel has arrived which means we've just completed a // funding workflow. We'll initialize the necessary local // state, and notify the htlc switch of a new link. case newChanReq := <-p.newChannels: newChan := newChanReq.channel chanPoint := &newChan.FundingOutpoint chanID := lnwire.NewChanIDFromOutPoint(chanPoint) // Only update RemoteNextRevocation if the channel is in the // activeChannels map and if we added the link to the switch. // Only active channels will be added to the switch. p.activeChanMtx.Lock() currentChan, ok := p.activeChannels[chanID] if ok && currentChan != nil { peerLog.Infof("Already have ChannelPoint(%v), "+ "ignoring.", chanPoint) p.activeChanMtx.Unlock() close(newChanReq.err) // If we're being sent a new channel, and our // existing channel doesn't have the next // revocation, then we need to update the // current existing channel. if currentChan.RemoteNextRevocation() != nil { continue } peerLog.Infof("Processing retransmitted "+ "FundingLocked for ChannelPoint(%v)", chanPoint) nextRevoke := newChan.RemoteNextRevocation err := currentChan.InitNextRevocation(nextRevoke) if err != nil { peerLog.Errorf("unable to init chan "+ "revocation: %v", err) continue } continue } // If not already active, we'll add this channel to the // set of active channels, so we can look it up later // easily according to its channel ID. lnChan, err := lnwallet.NewLightningChannel( p.cfg.Signer, newChan, p.cfg.SigPool, ) if err != nil { p.activeChanMtx.Unlock() err := fmt.Errorf("unable to create "+ "LightningChannel: %v", err) peerLog.Errorf(err.Error()) newChanReq.err <- err continue } // This refreshes the activeChannels entry if the link was not in // the switch, also populates for new entries. p.activeChannels[chanID] = lnChan p.addedChannels[chanID] = struct{}{} p.activeChanMtx.Unlock() peerLog.Infof("New channel active ChannelPoint(%v) "+ "with NodeKey(%x)", chanPoint, p.PubKey()) // Next, we'll assemble a ChannelLink along with the // necessary items it needs to function. // // TODO(roasbeef): panic on below? chainEvents, err := p.cfg.ChainArb.SubscribeChannelEvents( *chanPoint, ) if err != nil { err := fmt.Errorf("unable to subscribe to "+ "chain events: %v", err) peerLog.Errorf(err.Error()) newChanReq.err <- err continue } // We'll query the localChanCfg of the new channel to determine the // minimum HTLC value that can be forwarded. For the maximum HTLC // value that can be forwarded and fees we'll use the default // values, as they currently are always set to the default values // at initial channel creation. Note that the maximum HTLC value // defaults to the cap on the total value of outstanding HTLCs. fwdMinHtlc := lnChan.FwdMinHtlc() defaultPolicy := p.cfg.RoutingPolicy forwardingPolicy := &htlcswitch.ForwardingPolicy{ MinHTLCOut: fwdMinHtlc, MaxHTLC: newChan.LocalChanCfg.MaxPendingAmount, BaseFee: defaultPolicy.BaseFee, FeeRate: defaultPolicy.FeeRate, TimeLockDelta: defaultPolicy.TimeLockDelta, } // If we've reached this point, there are two possible scenarios. // If the channel was in the active channels map as nil, then it // was loaded from disk and we need to send reestablish. Else, // it was not loaded from disk and we don't need to send // reestablish as this is a fresh channel. shouldReestablish := ok // Create the link and add it to the switch. err = p.addLink( chanPoint, lnChan, forwardingPolicy, chainEvents, shouldReestablish, ) if err != nil { err := fmt.Errorf("can't register new channel "+ "link(%v) with NodeKey(%x)", chanPoint, p.PubKey()) peerLog.Errorf(err.Error()) newChanReq.err <- err continue } close(newChanReq.err) // We've just received a local request to close an active // channel. It will either kick of a cooperative channel // closure negotiation, or be a notification of a breached // contract that should be abandoned. case req := <-p.localCloseChanReqs: p.handleLocalCloseReq(req) // We've received a link failure from a link that was added to // the switch. This will initiate the teardown of the link, and // initiate any on-chain closures if necessary. case failure := <-p.linkFailures: p.handleLinkFailure(failure) // We've received a new cooperative channel closure related // message from the remote peer, we'll use this message to // advance the chan closer state machine. case closeMsg := <-p.chanCloseMsgs: p.handleCloseMsg(closeMsg) // The channel reannounce delay has elapsed, broadcast the // reenabled channel updates to the network. This should only // fire once, so we set the reenableTimeout channel to nil to // mark it for garbage collection. If the peer is torn down // before firing, reenabling will not be attempted. // TODO(conner): consolidate reenables timers inside chan status // manager case <-reenableTimeout: p.reenableActiveChannels() // Since this channel will never fire again during the // lifecycle of the peer, we nil the channel to mark it // eligible for garbage collection, and make this // explicitly ineligible to receive in future calls to // select. This also shaves a few CPU cycles since the // select will ignore this case entirely. reenableTimeout = nil case <-p.quit: // As, we've been signalled to exit, we'll reset all // our active channel back to their default state. p.activeChanMtx.Lock() for _, channel := range p.activeChannels { // If the channel is nil, continue as it's a pending channel. if channel == nil { continue } channel.ResetState() } p.activeChanMtx.Unlock() break out } } } // reenableActiveChannels searches the index of channels maintained with this // peer, and reenables each public, non-pending channel. This is done at the // gossip level by broadcasting a new ChannelUpdate with the disabled bit unset. // No message will be sent if the channel is already enabled. func (p *Brontide) reenableActiveChannels() { // First, filter all known channels with this peer for ones that are // both public and not pending. var activePublicChans []wire.OutPoint p.activeChanMtx.RLock() for chanID, lnChan := range p.activeChannels { // If the lnChan is nil, continue as this is a pending channel. if lnChan == nil { continue } dbChan := lnChan.State() isPublic := dbChan.ChannelFlags&lnwire.FFAnnounceChannel != 0 if !isPublic || dbChan.IsPending { continue } // We'll also skip any channels added during this peer's // lifecycle since they haven't waited out the timeout. Their // first announcement will be enabled, and the chan status // manager will begin monitoring them passively since they exist // in the database. if _, ok := p.addedChannels[chanID]; ok { continue } activePublicChans = append( activePublicChans, dbChan.FundingOutpoint, ) } p.activeChanMtx.RUnlock() // For each of the public, non-pending channels, set the channel // disabled bit to false and send out a new ChannelUpdate. If this // channel is already active, the update won't be sent. for _, chanPoint := range activePublicChans { err := p.cfg.ChanStatusMgr.RequestEnable(chanPoint) if err != nil { peerLog.Errorf("Unable to enable channel %v: %v", chanPoint, err) } } } // fetchActiveChanCloser attempts to fetch the active chan closer state machine // for the target channel ID. If the channel isn't active an error is returned. // Otherwise, either an existing state machine will be returned, or a new one // will be created. func (p *Brontide) fetchActiveChanCloser(chanID lnwire.ChannelID) ( *chancloser.ChanCloser, error) { // First, we'll ensure that we actually know of the target channel. If // not, we'll ignore this message. p.activeChanMtx.RLock() channel, ok := p.activeChannels[chanID] p.activeChanMtx.RUnlock() // If the channel isn't in the map or the channel is nil, return // ErrChannelNotFound as the channel is pending. if !ok || channel == nil { return nil, ErrChannelNotFound } // We'll attempt to look up the matching state machine, if we can't // find one then this means that the remote party is initiating a // cooperative channel closure. chanCloser, ok := p.activeChanCloses[chanID] if !ok { // If we need to create a chan closer for the first time, then // we'll check to ensure that the channel is even in the proper // state to allow a co-op channel closure. if len(channel.ActiveHtlcs()) != 0 { return nil, fmt.Errorf("cannot co-op close " + "channel w/ active htlcs") } // We'll create a valid closing state machine in order to respond to the // initiated cooperative channel closure. First, we set the delivery // script that our funds will be paid out to. If an upfront shutdown script // was set, we will use it. Otherwise, we get a fresh delivery script. deliveryScript := channel.LocalUpfrontShutdownScript() if len(deliveryScript) == 0 { var err error deliveryScript, err = p.genDeliveryScript() if err != nil { peerLog.Errorf("unable to gen delivery script: %v", err) return nil, fmt.Errorf("close addr unavailable") } } // In order to begin fee negotiations, we'll first compute our // target ideal fee-per-kw. We'll set this to a lax value, as // we weren't the ones that initiated the channel closure. feePerKw, err := p.cfg.FeeEstimator.EstimateFeePerKW(6) if err != nil { peerLog.Errorf("unable to query fee estimator: %v", err) return nil, fmt.Errorf("unable to estimate fee") } _, startingHeight, err := p.cfg.ChainIO.GetBestBlock() if err != nil { peerLog.Errorf("unable to obtain best block: %v", err) return nil, fmt.Errorf("cannot obtain best block") } chanCloser = chancloser.NewChanCloser( chancloser.ChanCloseCfg{ Channel: channel, UnregisterChannel: p.cfg.Switch.RemoveLink, BroadcastTx: p.cfg.Wallet.PublishTransaction, DisableChannel: p.cfg.ChanStatusMgr.RequestDisable, Disconnect: func() error { return p.cfg.DisconnectPeer(p.IdentityKey()) }, Quit: p.quit, }, deliveryScript, feePerKw, uint32(startingHeight), nil, false, ) p.activeChanCloses[chanID] = chanCloser } return chanCloser, nil } // chooseDeliveryScript takes two optionally set shutdown scripts and returns // a suitable script to close out to. This may be nil if neither script is // set. If both scripts are set, this function will error if they do not match. func chooseDeliveryScript(upfront, requested lnwire.DeliveryAddress) (lnwire.DeliveryAddress, error) { // If no upfront shutdown script was provided, return the user // requested address (which may be nil). if len(upfront) == 0 { return requested, nil } // If an upfront shutdown script was provided, and the user did not request // a custom shutdown script, return the upfront address. if len(requested) == 0 { return upfront, nil } // If both an upfront shutdown script and a custom close script were // provided, error if the user provided shutdown script does not match // the upfront shutdown script (because closing out to a different script // would violate upfront shutdown). if !bytes.Equal(upfront, requested) { return nil, chancloser.ErrUpfrontShutdownScriptMismatch } // The user requested script matches the upfront shutdown script, so we // can return it without error. return upfront, nil } // handleLocalCloseReq kicks-off the workflow to execute a cooperative or // forced unilateral closure of the channel initiated by a local subsystem. func (p *Brontide) handleLocalCloseReq(req *htlcswitch.ChanClose) { chanID := lnwire.NewChanIDFromOutPoint(req.ChanPoint) p.activeChanMtx.RLock() channel, ok := p.activeChannels[chanID] p.activeChanMtx.RUnlock() // Though this function can't be called for pending channels, we still // check whether channel is nil for safety. if !ok || channel == nil { err := fmt.Errorf("unable to close channel, ChannelID(%v) is "+ "unknown", chanID) peerLog.Errorf(err.Error()) req.Err <- err return } switch req.CloseType { // A type of CloseRegular indicates that the user has opted to close // out this channel on-chain, so we execute the cooperative channel // closure workflow. case htlcswitch.CloseRegular: // First, we'll choose a delivery address that we'll use to send the // funds to in the case of a successful negotiation. // An upfront shutdown and user provided script are both optional, // but must be equal if both set (because we cannot serve a request // to close out to a script which violates upfront shutdown). Get the // appropriate address to close out to (which may be nil if neither // are set) and error if they are both set and do not match. deliveryScript, err := chooseDeliveryScript( channel.LocalUpfrontShutdownScript(), req.DeliveryScript, ) if err != nil { peerLog.Errorf("cannot close channel %v: %v", req.ChanPoint, err) req.Err <- err return } // If neither an upfront address or a user set address was // provided, generate a fresh script. if len(deliveryScript) == 0 { deliveryScript, err = p.genDeliveryScript() if err != nil { peerLog.Errorf(err.Error()) req.Err <- err return } } // Next, we'll create a new channel closer state machine to // handle the close negotiation. _, startingHeight, err := p.cfg.ChainIO.GetBestBlock() if err != nil { peerLog.Errorf(err.Error()) req.Err <- err return } chanCloser := chancloser.NewChanCloser( chancloser.ChanCloseCfg{ Channel: channel, UnregisterChannel: p.cfg.Switch.RemoveLink, BroadcastTx: p.cfg.Wallet.PublishTransaction, DisableChannel: p.cfg.ChanStatusMgr.RequestDisable, Disconnect: func() error { return p.cfg.DisconnectPeer(p.IdentityKey()) }, Quit: p.quit, }, deliveryScript, req.TargetFeePerKw, uint32(startingHeight), req, true, ) p.activeChanCloses[chanID] = chanCloser // Finally, we'll initiate the channel shutdown within the // chanCloser, and send the shutdown message to the remote // party to kick things off. shutdownMsg, err := chanCloser.ShutdownChan() if err != nil { peerLog.Errorf(err.Error()) req.Err <- err delete(p.activeChanCloses, chanID) // As we were unable to shutdown the channel, we'll // return it back to its normal state. channel.ResetState() return } p.queueMsg(shutdownMsg, nil) // A type of CloseBreach indicates that the counterparty has breached // the channel therefore we need to clean up our local state. case htlcswitch.CloseBreach: // TODO(roasbeef): no longer need with newer beach logic? peerLog.Infof("ChannelPoint(%v) has been breached, wiping "+ "channel", req.ChanPoint) p.WipeChannel(req.ChanPoint) } } // linkFailureReport is sent to the channelManager whenever a link reports a // link failure, and is forced to exit. The report houses the necessary // information to clean up the channel state, send back the error message, and // force close if necessary. type linkFailureReport struct { chanPoint wire.OutPoint chanID lnwire.ChannelID shortChanID lnwire.ShortChannelID linkErr htlcswitch.LinkFailureError } // handleLinkFailure processes a link failure report when a link in the switch // fails. It facilitates the removal of all channel state within the peer, // force closing the channel depending on severity, and sending the error // message back to the remote party. func (p *Brontide) handleLinkFailure(failure linkFailureReport) { // Retrieve the channel from the map of active channels. We do this to // have access to it even after WipeChannel remove it from the map. chanID := lnwire.NewChanIDFromOutPoint(&failure.chanPoint) p.activeChanMtx.Lock() lnChan := p.activeChannels[chanID] p.activeChanMtx.Unlock() // We begin by wiping the link, which will remove it from the switch, // such that it won't be attempted used for any more updates. // // TODO(halseth): should introduce a way to atomically stop/pause the // link and cancel back any adds in its mailboxes such that we can // safely force close without the link being added again and updates // being applied. p.WipeChannel(&failure.chanPoint) // If the error encountered was severe enough, we'll now force close the // channel to prevent reading it to the switch in the future. if failure.linkErr.ForceClose { peerLog.Warnf("Force closing link(%v)", failure.shortChanID) closeTx, err := p.cfg.ChainArb.ForceCloseContract( failure.chanPoint, ) if err != nil { peerLog.Errorf("unable to force close "+ "link(%v): %v", failure.shortChanID, err) } else { peerLog.Infof("channel(%v) force "+ "closed with txid %v", failure.shortChanID, closeTx.TxHash()) } } // If this is a permanent failure, we will mark the channel borked. if failure.linkErr.PermanentFailure && lnChan != nil { peerLog.Warnf("Marking link(%v) borked due to permanent "+ "failure", failure.shortChanID) if err := lnChan.State().MarkBorked(); err != nil { peerLog.Errorf("Unable to mark channel %v borked: %v", failure.shortChanID, err) } } // Send an error to the peer, why we failed the channel. if failure.linkErr.ShouldSendToPeer() { // If SendData is set, send it to the peer. If not, we'll use // the standard error messages in the payload. We only include // sendData in the cases where the error data does not contain // sensitive information. data := []byte(failure.linkErr.Error()) if failure.linkErr.SendData != nil { data = failure.linkErr.SendData } err := p.SendMessage(true, &lnwire.Error{ ChanID: failure.chanID, Data: data, }) if err != nil { peerLog.Errorf("unable to send msg to "+ "remote peer: %v", err) } } } // finalizeChanClosure performs the final clean up steps once the cooperative // closure transaction has been fully broadcast. The finalized closing state // machine should be passed in. Once the transaction has been sufficiently // confirmed, the channel will be marked as fully closed within the database, // and any clients will be notified of updates to the closing state. func (p *Brontide) finalizeChanClosure(chanCloser *chancloser.ChanCloser) { closeReq := chanCloser.CloseRequest() // First, we'll clear all indexes related to the channel in question. chanPoint := chanCloser.Channel().ChannelPoint() p.WipeChannel(chanPoint) // Next, we'll launch a goroutine which will request to be notified by // the ChainNotifier once the closure transaction obtains a single // confirmation. notifier := p.cfg.ChainNotifier // If any error happens during waitForChanToClose, forward it to // closeReq. If this channel closure is not locally initiated, closeReq // will be nil, so just ignore the error. errChan := make(chan error, 1) if closeReq != nil { errChan = closeReq.Err } closingTx, err := chanCloser.ClosingTx() if err != nil { if closeReq != nil { peerLog.Error(err) closeReq.Err <- err } } closingTxid := closingTx.TxHash() // If this is a locally requested shutdown, update the caller with a // new event detailing the current pending state of this request. if closeReq != nil { closeReq.Updates <- &PendingUpdate{ Txid: closingTxid[:], } } go WaitForChanToClose(chanCloser.NegotiationHeight(), notifier, errChan, chanPoint, &closingTxid, closingTx.TxOut[0].PkScript, func() { // Respond to the local subsystem which requested the // channel closure. if closeReq != nil { closeReq.Updates <- &ChannelCloseUpdate{ ClosingTxid: closingTxid[:], Success: true, } } }) } // WaitForChanToClose uses the passed notifier to wait until the channel has // been detected as closed on chain and then concludes by executing the // following actions: the channel point will be sent over the settleChan, and // finally the callback will be executed. If any error is encountered within // the function, then it will be sent over the errChan. func WaitForChanToClose(bestHeight uint32, notifier chainntnfs.ChainNotifier, errChan chan error, chanPoint *wire.OutPoint, closingTxID *chainhash.Hash, closeScript []byte, cb func()) { peerLog.Infof("Waiting for confirmation of cooperative close of "+ "ChannelPoint(%v) with txid: %v", chanPoint, closingTxID) // TODO(roasbeef): add param for num needed confs confNtfn, err := notifier.RegisterConfirmationsNtfn( closingTxID, closeScript, 1, bestHeight, ) if err != nil { if errChan != nil { errChan <- err } return } // In the case that the ChainNotifier is shutting down, all subscriber // notification channels will be closed, generating a nil receive. height, ok := <-confNtfn.Confirmed if !ok { return } // The channel has been closed, remove it from any active indexes, and // the database state. peerLog.Infof("ChannelPoint(%v) is now closed at "+ "height %v", chanPoint, height.BlockHeight) // Finally, execute the closure call back to mark the confirmation of // the transaction closing the contract. cb() } // WipeChannel removes the passed channel point from all indexes associated with // the peer and the switch. func (p *Brontide) WipeChannel(chanPoint *wire.OutPoint) { chanID := lnwire.NewChanIDFromOutPoint(chanPoint) p.activeChanMtx.Lock() delete(p.activeChannels, chanID) p.activeChanMtx.Unlock() // Instruct the HtlcSwitch to close this link as the channel is no // longer active. p.cfg.Switch.RemoveLink(chanID) } // handleInitMsg handles the incoming init message which contains global and // local feature vectors. If feature vectors are incompatible then disconnect. func (p *Brontide) handleInitMsg(msg *lnwire.Init) error { // First, merge any features from the legacy global features field into // those presented in the local features fields. err := msg.Features.Merge(msg.GlobalFeatures) if err != nil { return fmt.Errorf("unable to merge legacy global features: %v", err) } // Then, finalize the remote feature vector providing the flattened // feature bit namespace. p.remoteFeatures = lnwire.NewFeatureVector( msg.Features, lnwire.Features, ) // Now that we have their features loaded, we'll ensure that they // didn't set any required bits that we don't know of. err = feature.ValidateRequired(p.remoteFeatures) if err != nil { return fmt.Errorf("invalid remote features: %v", err) } // Ensure the remote party's feature vector contains all transitive // dependencies. We know ours are correct since they are validated // during the feature manager's instantiation. err = feature.ValidateDeps(p.remoteFeatures) if err != nil { return fmt.Errorf("invalid remote features: %v", err) } // Now that we know we understand their requirements, we'll check to // see if they don't support anything that we deem to be mandatory. if !p.remoteFeatures.HasFeature(lnwire.DataLossProtectRequired) { return fmt.Errorf("data loss protection required") } return nil } // LocalFeatures returns the set of global features that has been advertised by // the local node. This allows sub-systems that use this interface to gate their // behavior off the set of negotiated feature bits. // // NOTE: Part of the lnpeer.Peer interface. func (p *Brontide) LocalFeatures() *lnwire.FeatureVector { return p.cfg.Features } // RemoteFeatures returns the set of global features that has been advertised by // the remote node. This allows sub-systems that use this interface to gate // their behavior off the set of negotiated feature bits. // // NOTE: Part of the lnpeer.Peer interface. func (p *Brontide) RemoteFeatures() *lnwire.FeatureVector { return p.remoteFeatures } // sendInitMsg sends the Init message to the remote peer. This message contains // our currently supported local and global features. func (p *Brontide) sendInitMsg(legacyChan bool) error { features := p.cfg.Features.Clone() // If we have a legacy channel open with a peer, we downgrade static // remote required to optional in case the peer does not understand the // required feature bit. If we do not do this, the peer will reject our // connection because it does not understand a required feature bit, and // our channel will be unusable. if legacyChan && features.RequiresFeature(lnwire.StaticRemoteKeyRequired) { peerLog.Infof("Legacy channel open with peer: %x, "+ "downgrading static remote required feature bit to "+ "optional", p.PubKey()) features.Unset(lnwire.StaticRemoteKeyRequired) features.Set(lnwire.StaticRemoteKeyOptional) } msg := lnwire.NewInitMessage( p.cfg.LegacyFeatures.RawFeatureVector, features.RawFeatureVector, ) return p.writeMessage(msg) } // resendChanSyncMsg will attempt to find a channel sync message for the closed // channel and resend it to our peer. func (p *Brontide) resendChanSyncMsg(cid lnwire.ChannelID) error { // If we already re-sent the mssage for this channel, we won't do it // again. if _, ok := p.resentChanSyncMsg[cid]; ok { return nil } // Check if we have any channel sync messages stored for this channel. c, err := p.cfg.ChannelDB.FetchClosedChannelForID(cid) if err != nil { return fmt.Errorf("unable to fetch channel sync messages for "+ "peer %v: %v", p, err) } if c.LastChanSyncMsg == nil { return fmt.Errorf("no chan sync message stored for channel %v", cid) } if !c.RemotePub.IsEqual(p.IdentityKey()) { return fmt.Errorf("ignoring channel reestablish from "+ "peer=%x", p.IdentityKey()) } peerLog.Debugf("Re-sending channel sync message for channel %v to "+ "peer %v", cid, p) if err := p.SendMessage(true, c.LastChanSyncMsg); err != nil { return fmt.Errorf("failed resending channel sync "+ "message to peer %v: %v", p, err) } peerLog.Debugf("Re-sent channel sync message for channel %v to peer "+ "%v", cid, p) // Note down that we sent the message, so we won't resend it again for // this connection. p.resentChanSyncMsg[cid] = struct{}{} return nil } // SendMessage sends a variadic number of high-priority messages to the remote // peer. The first argument denotes if the method should block until the // messages have been sent to the remote peer or an error is returned, // otherwise it returns immediately after queuing. // // NOTE: Part of the lnpeer.Peer interface. func (p *Brontide) SendMessage(sync bool, msgs ...lnwire.Message) error { return p.sendMessage(sync, true, msgs...) } // SendMessageLazy sends a variadic number of low-priority messages to the // remote peer. The first argument denotes if the method should block until // the messages have been sent to the remote peer or an error is returned, // otherwise it returns immediately after queueing. // // NOTE: Part of the lnpeer.Peer interface. func (p *Brontide) SendMessageLazy(sync bool, msgs ...lnwire.Message) error { return p.sendMessage(sync, false, msgs...) } // sendMessage queues a variadic number of messages using the passed priority // to the remote peer. If sync is true, this method will block until the // messages have been sent to the remote peer or an error is returned, otherwise // it returns immediately after queueing. func (p *Brontide) sendMessage(sync, priority bool, msgs ...lnwire.Message) error { // Add all incoming messages to the outgoing queue. A list of error // chans is populated for each message if the caller requested a sync // send. var errChans []chan error if sync { errChans = make([]chan error, 0, len(msgs)) } for _, msg := range msgs { // If a sync send was requested, create an error chan to listen // for an ack from the writeHandler. var errChan chan error if sync { errChan = make(chan error, 1) errChans = append(errChans, errChan) } if priority { p.queueMsg(msg, errChan) } else { p.queueMsgLazy(msg, errChan) } } // Wait for all replies from the writeHandler. For async sends, this // will be a NOP as the list of error chans is nil. for _, errChan := range errChans { select { case err := <-errChan: return err case <-p.quit: return lnpeer.ErrPeerExiting case <-p.cfg.Quit: return lnpeer.ErrPeerExiting } } return nil } // PubKey returns the pubkey of the peer in compressed serialized format. // // NOTE: Part of the lnpeer.Peer interface. func (p *Brontide) PubKey() [33]byte { return p.cfg.PubKeyBytes } // IdentityKey returns the public key of the remote peer. // // NOTE: Part of the lnpeer.Peer interface. func (p *Brontide) IdentityKey() *btcec.PublicKey { return p.cfg.Addr.IdentityKey } // Address returns the network address of the remote peer. // // NOTE: Part of the lnpeer.Peer interface. func (p *Brontide) Address() net.Addr { return p.cfg.Addr.Address } // AddNewChannel adds a new channel to the peer. The channel should fail to be // added if the cancel channel is closed. // // NOTE: Part of the lnpeer.Peer interface. func (p *Brontide) AddNewChannel(channel *channeldb.OpenChannel, cancel <-chan struct{}) error { errChan := make(chan error, 1) newChanMsg := &newChannelMsg{ channel: channel, err: errChan, } select { case p.newChannels <- newChanMsg: case <-cancel: return errors.New("canceled adding new channel") case <-p.quit: return lnpeer.ErrPeerExiting } // 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 err := <-errChan: return err case <-p.quit: return lnpeer.ErrPeerExiting } } // StartTime returns the time at which the connection was established if the // peer started successfully, and zero otherwise. func (p *Brontide) StartTime() time.Time { return p.startTime } // handleCloseMsg is called when a new cooperative channel closure related // message is received from the remote peer. We'll use this message to advance // the chan closer state machine. func (p *Brontide) handleCloseMsg(msg *closeMsg) { // We'll now fetch the matching closing state machine in order to continue, // or finalize the channel closure process. chanCloser, err := p.fetchActiveChanCloser(msg.cid) if err != nil { // If the channel is not known to us, we'll simply ignore this message. if err == ErrChannelNotFound { return } peerLog.Errorf("Unable to respond to remote close msg: %v", err) errMsg := &lnwire.Error{ ChanID: msg.cid, Data: lnwire.ErrorData(err.Error()), } p.queueMsg(errMsg, nil) return } // Next, we'll process the next message using the target state machine. // We'll either continue negotiation, or halt. msgs, closeFin, err := chanCloser.ProcessCloseMsg( msg.msg, ) if err != nil { err := fmt.Errorf("unable to process close msg: %v", err) peerLog.Error(err) // As the negotiations failed, we'll reset the channel state machine to // ensure we act to on-chain events as normal. chanCloser.Channel().ResetState() if chanCloser.CloseRequest() != nil { chanCloser.CloseRequest().Err <- err } delete(p.activeChanCloses, msg.cid) return } // Queue any messages to the remote peer that need to be sent as a part of // this latest round of negotiations. for _, msg := range msgs { p.queueMsg(msg, nil) } // If we haven't finished close negotiations, then we'll continue as we // can't yet finalize the closure. if !closeFin { return } // Otherwise, we've agreed on a closing fee! In this case, we'll wrap up // the channel closure by notifying relevant sub-systems and launching a // goroutine to wait for close tx conf. p.finalizeChanClosure(chanCloser) } // HandleLocalCloseChanReqs accepts a *htlcswitch.ChanClose and passes it onto // the channelManager goroutine, which will shut down the link and possibly // close the channel. func (p *Brontide) HandleLocalCloseChanReqs(req *htlcswitch.ChanClose) { select { case p.localCloseChanReqs <- req: peerLog.Infof("Local close channel request delivered to "+ "peer: %x", p.PubKey()) case <-p.quit: peerLog.Infof("Unable to deliver local close channel request "+ "to peer %x", p.PubKey()) } } // NetAddress returns the network of the remote peer as an lnwire.NetAddress. func (p *Brontide) NetAddress() *lnwire.NetAddress { return p.cfg.Addr } // Inbound is a getter for the Brontide's Inbound boolean in cfg. func (p *Brontide) Inbound() bool { return p.cfg.Inbound } // ConnReq is a getter for the Brontide's connReq in cfg. func (p *Brontide) ConnReq() *connmgr.ConnReq { return p.cfg.ConnReq } // ErrorBuffer is a getter for the Brontide's errorBuffer in cfg. func (p *Brontide) ErrorBuffer() *queue.CircularBuffer { return p.cfg.ErrorBuffer } // SetAddress sets the remote peer's address given an address. func (p *Brontide) SetAddress(address net.Addr) { p.cfg.Addr.Address = address } // ActiveSignal returns the peer's active signal. func (p *Brontide) ActiveSignal() chan struct{} { return p.activeSignal } // Conn returns a pointer to the peer's connection struct. func (p *Brontide) Conn() net.Conn { return p.cfg.Conn } // BytesReceived returns the number of bytes received from the peer. func (p *Brontide) BytesReceived() uint64 { return atomic.LoadUint64(&p.bytesReceived) } // BytesSent returns the number of bytes sent to the peer. func (p *Brontide) BytesSent() uint64 { return atomic.LoadUint64(&p.bytesSent) }