package main 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/brontide" "github.com/lightningnetwork/lnd/chainntnfs" "github.com/lightningnetwork/lnd/channeldb" "github.com/lightningnetwork/lnd/contractcourt" "github.com/lightningnetwork/lnd/htlcswitch" "github.com/lightningnetwork/lnd/lnpeer" "github.com/lightningnetwork/lnd/lnwallet" "github.com/lightningnetwork/lnd/lnwire" "github.com/lightningnetwork/lnd/ticker" ) var ( numNodes int32 // ErrPeerExiting signals that the peer received a disconnect request. ErrPeerExiting = fmt.Errorf("peer exiting") ) 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 peer. writeMessageTimeout = 50 * time.Second // handshakeTimeout is the timeout used when waiting for peer 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 ) // 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 { 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 funding transaction has been // confirmed and the channel creation process completed. type newChannelMsg struct { channel *channeldb.OpenChannel err chan error } // closeMsgs 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 } // chanSnapshotReq is a message sent by outside subsystems to a peer in order // to gain a snapshot of the peer's currently active channels. type chanSnapshotReq struct { resp chan []*channeldb.ChannelSnapshot } // 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 } // peer 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 peer struct { // MUST be used atomically. started int32 disconnect int32 // The following fields are only meant to 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 micro seconds. // 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 connReq *connmgr.ConnReq conn net.Conn addr *lnwire.NetAddress pubKeyBytes [33]byte // startTime is the time this peer connection was successfully // established. It will be zero for peers that did not successfully // Start(). startTime time.Time inbound bool // sendQueue is the channel which is used to queue outgoing 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 // 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. activeChanMtx sync.RWMutex activeChannels map[lnwire.ChannelID]*lnwallet.LightningChannel // newChannels is used by the fundingManager to send fully opened // channels to the source peer which handled the funding workflow. newChannels chan *newChannelMsg // activeChanCloses is a map that keep track of all the active // cooperative channel closures that are active. Any channel closing // messages are directed to one of these active state machines. Once // the channel has been closed, the state machine will be delete from // the map. activeChanCloses map[lnwire.ChannelID]*channelCloser // 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 server *server // localFeatures is the set of local features that we advertised to the // remote node. localFeatures *lnwire.RawFeatureVector // remoteLocalFeatures is the local feature vector received from the // peer during the connection handshake. remoteLocalFeatures *lnwire.FeatureVector // remoteGlobalFeatures is the global feature vector received from the // peer during the connection handshake. remoteGlobalFeatures *lnwire.FeatureVector // failedChannels is a set that tracks channels we consider `failed`. // This is a temporary measure until we have implemented real failure // handling at the link level, to handle the case where we reconnect to // a peer and try to re-sync a failed channel, triggering a disconnect // loop. // TODO(halseth): remove when link failure is properly handled. failedChannels map[lnwire.ChannelID]struct{} // writeBuf is a buffer that we'll re-use in order to encode wire // messages to write out directly on the socket. By re-using this // buffer, we avoid needing to allocate more memory each time a new // message is to be sent to a peer. writeBuf [lnwire.MaxMessagePayload]byte queueQuit chan struct{} quit chan struct{} wg sync.WaitGroup } // A compile-time check to ensure that peer satisfies the lnpeer.Peer interface. var _ lnpeer.Peer = (*peer)(nil) // newPeer creates a new peer from an establish connection object, and a // pointer to the main server. func newPeer(conn net.Conn, connReq *connmgr.ConnReq, server *server, addr *lnwire.NetAddress, inbound bool, localFeatures *lnwire.RawFeatureVector) (*peer, error) { nodePub := addr.IdentityKey p := &peer{ conn: conn, addr: addr, inbound: inbound, connReq: connReq, server: server, localFeatures: localFeatures, sendQueue: make(chan outgoingMsg), outgoingQueue: make(chan outgoingMsg), activeChannels: make(map[lnwire.ChannelID]*lnwallet.LightningChannel), newChannels: make(chan *newChannelMsg, 1), activeChanCloses: make(map[lnwire.ChannelID]*channelCloser), localCloseChanReqs: make(chan *htlcswitch.ChanClose), linkFailures: make(chan linkFailureReport), chanCloseMsgs: make(chan *closeMsg), failedChannels: make(map[lnwire.ChannelID]struct{}), queueQuit: make(chan struct{}), quit: make(chan struct{}), } copy(p.pubKeyBytes[:], nodePub.SerializeCompressed()) return p, nil } // 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 loop. func (p *peer) Start() error { if atomic.AddInt32(&p.started, 1) != 1 { return nil } peerLog.Tracef("Peer %v starting", p) // Exchange local and global features, the init message should be very // first between two nodes. if err := p.sendInitMsg(); 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 { return err } } else { return errors.New("very first message between nodes " + "must be init message") } // Fetch and then load all the active channels we have with this remote // peer from the database. activeChans, err := p.server.chanDB.FetchOpenChannels(p.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.server.prunePersistentPeerConnection(p.pubKeyBytes) } // 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()) if err := p.loadActiveChannels(activeChans); 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() return nil } // initGossipSync initializes either a gossip syncer or an initial routing // dump, depending on the negotiated synchronization method. func (p *peer) initGossipSync() { switch { // If the remote peer knows of the new gossip queries feature, then // we'll create a new gossipSyncer in the AuthenticatedGossiper for it. case p.remoteLocalFeatures.HasFeature(lnwire.GossipQueriesOptional): srvrLog.Infof("Negotiated chan series queries with %x", p.pubKeyBytes[:]) // We'll only request channel updates from the remote peer if // its enabled in the config, or we're already getting updates // from enough peers. // // TODO(roasbeef): craft s.t. we only get updates from a few // peers recvUpdates := !cfg.NoChanUpdates // Register the this peer's for gossip syncer with the gossiper. // This is blocks synchronously to ensure the gossip syncer is // registered with the gossiper before attempting to read // messages from the remote peer. p.server.authGossiper.InitSyncState(p, recvUpdates) // If the remote peer has the initial sync feature bit set, then we'll // being the synchronization protocol to exchange authenticated channel // graph edges/vertexes, but only if they don't know of the new gossip // queries. case p.remoteLocalFeatures.HasFeature(lnwire.InitialRoutingSync): srvrLog.Infof("Requesting full table sync with %x", p.pubKeyBytes[:]) go p.server.authGossiper.SynchronizeNode(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 *peer) QuitSignal() <-chan struct{} { return p.quit } // loadActiveChannels creates indexes within the peer for tracking all active // channels returned by the database. func (p *peer) loadActiveChannels(chans []*channeldb.OpenChannel) error { var activePublicChans []wire.OutPoint for _, dbChan := range chans { lnChan, err := lnwallet.NewLightningChannel( p.server.cc.signer, p.server.witnessBeacon, dbChan, p.server.sigPool, ) if err != nil { return 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.ChanStatus() != channeldb.Default { peerLog.Warnf("ChannelPoint(%v) has status %v, won't "+ "start.", chanPoint, dbChan.ChanStatus()) continue } // Also skip adding any channel marked as `failed` for this // session. if _, ok := p.failedChannels[chanID]; ok { peerLog.Warnf("ChannelPoint(%v) is failed, won't "+ "start.", chanPoint) continue } _, currentHeight, err := p.server.cc.chainIO.GetBestBlock() if err != nil { return err } // 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.server.chanDB.ChannelGraph() info, p1, p2, err := graph.FetchChannelEdgesByOutpoint(chanPoint) if err != nil && err != channeldb.ErrEdgeNotFound { return 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.server.identityPriv.PubKey().SerializeCompressed()) { 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{ MinHTLC: selfPolicy.MinHTLC, 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.server.cc.routingPolicy } peerLog.Tracef("Using link policy of: %v", spew.Sdump(forwardingPolicy)) // Register this new channel link with the HTLC Switch. This is // necessary to properly route multi-hop payments, and forward // new payments triggered by RPC clients. chainEvents, err := p.server.chainArb.SubscribeChannelEvents( *chanPoint, ) if err != nil { return err } // Create the link and add it to the switch. err = p.addLink( chanPoint, lnChan, forwardingPolicy, chainEvents, currentHeight, true, ) if err != nil { return fmt.Errorf("unable to add link %v to switch: %v", chanPoint, err) } p.activeChanMtx.Lock() p.activeChannels[chanID] = lnChan p.activeChanMtx.Unlock() // To ensure we can route through this channel now that the peer // is back online, we'll attempt to send an update to enable it. // This will only be used for non-pending public channels, as // they are the only ones capable of routing. chanIsPublic := dbChan.ChannelFlags&lnwire.FFAnnounceChannel != 0 if chanIsPublic && !dbChan.IsPending { activePublicChans = append(activePublicChans, *chanPoint) } } // As a final measure we launch a goroutine that will ensure the newly // loaded public channels are not currently disabled, as that will make // us skip it during path finding. go func() { for _, chanPoint := range activePublicChans { // Set the channel disabled=false by sending out a new // ChannelUpdate. If this channel is already active, // the update won't be sent. err := p.server.announceChanStatus(chanPoint, false) if err != nil && err != channeldb.ErrEdgeNotFound { srvrLog.Errorf("Unable to enable channel %v: %v", chanPoint, err) } } }() return nil } // addLink creates and adds a new link from the specified channel. func (p *peer) addLink(chanPoint *wire.OutPoint, lnChan *lnwallet.LightningChannel, forwardingPolicy *htlcswitch.ForwardingPolicy, chainEvents *contractcourt.ChainEventSubscription, currentHeight int32, 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.server.quit: } } linkCfg := htlcswitch.ChannelLinkConfig{ Peer: p, DecodeHopIterators: p.server.sphinx.DecodeHopIterators, ExtractErrorEncrypter: p.server.sphinx.ExtractErrorEncrypter, FetchLastChannelUpdate: p.server.fetchLastChanUpdate(), DebugHTLC: cfg.DebugHTLC, HodlMask: cfg.Hodl.Mask(), Registry: p.server.invoices, Switch: p.server.htlcSwitch, Circuits: p.server.htlcSwitch.CircuitModifier(), ForwardPackets: p.server.htlcSwitch.ForwardPackets, FwrdingPolicy: *forwardingPolicy, FeeEstimator: p.server.cc.feeEstimator, PreimageCache: p.server.witnessBeacon, ChainEvents: chainEvents, UpdateContractSignals: func(signals *contractcourt.ContractSignals) error { return p.server.chainArb.UpdateContractSignals( *chanPoint, signals, ) }, OnChannelFailure: onChannelFailure, SyncStates: syncStates, BatchTicker: ticker.New(50 * time.Millisecond), FwdPkgGCTicker: ticker.New(time.Minute), BatchSize: 10, UnsafeReplay: cfg.UnsafeReplay, MinFeeUpdateTimeout: htlcswitch.DefaultMinLinkFeeUpdateTimeout, MaxFeeUpdateTimeout: htlcswitch.DefaultMaxLinkFeeUpdateTimeout, } 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.server.htlcSwitch.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.server.htlcSwitch.AddLink(link) } // WaitForDisconnect waits until the peer has disconnected. A peer may be // disconnected if the local or remote side terminating 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 *peer) 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 *peer) Disconnect(reason error) { if !atomic.CompareAndSwapInt32(&p.disconnect, 0, 1) { return } peerLog.Infof("Disconnecting %s, reason: %v", p, reason) // Ensure that the TCP connection is properly closed before continuing. p.conn.Close() close(p.quit) } // String returns the string representation of this peer. func (p *peer) String() string { return p.conn.RemoteAddr().String() } // readNextMessage reads, and returns the next message on the wire along with // any additional raw payload. func (p *peer) readNextMessage() (lnwire.Message, error) { noiseConn, ok := p.conn.(*brontide.Conn) if !ok { return nil, fmt.Errorf("brontide.Conn required to read messages") } // 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. rawMsg, err := noiseConn.ReadNextMessage() 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 *peer apply func(lnwire.Message) startMsg string stopMsg string msgCond *sync.Cond msgs []lnwire.Message mtx sync.Mutex bufSize uint32 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 *peer, 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() } // 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 his held in scope to prevent unnecessary // lookups. func newChanMsgStream(p *peer, cid lnwire.ChannelID) *msgStream { var chanLink htlcswitch.ChannelLink return newMsgStream(p, fmt.Sprintf("Update stream for ChannelID(%x) created", cid[:]), fmt.Sprintf("Update stream for ChannelID(%x) exiting", cid[:]), 1000, func(msg lnwire.Message) { _, isChanSyncMsg := msg.(*lnwire.ChannelReestablish) // If this is the chanSync message, then we'll deliver // it immediately to the active link. if !isChanSyncMsg { // We'll send a message to the funding manager // and wait iff an active funding process for // this channel hasn't yet completed. We do // this in order to account for the following // scenario: we send the funding locked message // to the other side, they immediately send a // channel update message, but we haven't yet // sent the channel to the channelManager. err := p.server.fundingMgr.waitUntilChannelOpen( cid, p.quit, ) if err != nil { // If we have a non-nil error, then the // funding manager is shutting down, s // we can exit here without attempting // to deliver the message. 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: } // Dispatch the commitment update message to the proper // active goroutine dedicated to this channel. if chanLink == nil { link, err := p.server.htlcSwitch.GetLink(cid) switch { // 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. case err != nil && isChanSyncMsg: peerLog.Debugf("Unable to find "+ "link(%v) to handle channel "+ "sync, attempting to resend "+ "last ChanSync message", cid) err := p.resendChanSyncMsg(cid) if err != nil { // TODO(halseth): send error to // peer? peerLog.Errorf( "resend failed: %v", err, ) } return case err != nil: peerLog.Errorf("recv'd update for "+ "unknown channel %v from %v: "+ "%v", cid, p, err) return } chanLink = link } // 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) }, ) } // 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 *peer) *msgStream { return newMsgStream(p, "Update stream for gossiper created", "Update stream for gossiper exited", 1000, func(msg lnwire.Message) { p.server.authGossiper.ProcessRemoteAnnouncement(msg, p) }, ) } // 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 *peer) 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() chanMsgStreams := make(map[lnwire.ChannelID]*msgStream) out: for atomic.LoadInt32(&p.disconnect) == 0 { nextMsg, err := p.readNextMessage() idleTimer.Stop() if err != nil { peerLog.Infof("unable to read message from %v: %v", p, err) switch 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: idleTimer.Reset(idleTimeout) continue // If they sent us an address type that we don't yet // know of, then this isn't a dire error, so we'll // simply continue parsing the remainder of their // messages. case *lnwire.ErrUnknownAddrType: 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 messges from the peer. 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 s // this is a fatal error. default: break out } } var ( isChanUpdate bool targetChan lnwire.ChannelID ) 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: p.server.fundingMgr.processFundingOpen(msg, p) case *lnwire.AcceptChannel: p.server.fundingMgr.processFundingAccept(msg, p) case *lnwire.FundingCreated: p.server.fundingMgr.processFundingCreated(msg, p) case *lnwire.FundingSigned: p.server.fundingMgr.processFundingSigned(msg, p) case *lnwire.FundingLocked: p.server.fundingMgr.processFundingLocked(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: key := p.addr.IdentityKey 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 chanID, chanStream := range chanMsgStreams { chanStream.AddMsg(nextMsg) // Also marked this channel as failed, // so we won't try to restart it on // reconnect with this peer. p.failedChannels[chanID] = struct{}{} } // If the channel ID for the error message corresponds // to a pending channel, then the funding manager will // handle the error. case p.server.fundingMgr.IsPendingChannel(msg.ChanID, key): p.server.fundingMgr.processFundingError(msg, key) // If not we hand the error to the channel link for // this channel. default: isChanUpdate = true targetChan = msg.ChanID // Also marked this channel as failed, so we // won't try to restart it on reconnect with // this peer. p.failedChannels[targetChan] = struct{}{} } // TODO(roasbeef): create ChanUpdater interface for the below case *lnwire.UpdateAddHTLC: isChanUpdate = true targetChan = msg.ChanID case *lnwire.UpdateFulfillHTLC: isChanUpdate = true targetChan = msg.ChanID case *lnwire.UpdateFailMalformedHTLC: isChanUpdate = true targetChan = msg.ChanID case *lnwire.UpdateFailHTLC: isChanUpdate = true targetChan = msg.ChanID case *lnwire.RevokeAndAck: isChanUpdate = true targetChan = msg.ChanID case *lnwire.CommitSig: isChanUpdate = true targetChan = msg.ChanID case *lnwire.UpdateFee: isChanUpdate = true targetChan = msg.ChanID case *lnwire.ChannelReestablish: isChanUpdate = true targetChan = msg.ChanID case *lnwire.ChannelUpdate, *lnwire.ChannelAnnouncement, *lnwire.NodeAnnouncement, *lnwire.AnnounceSignatures, *lnwire.GossipTimestampRange, *lnwire.QueryShortChanIDs, *lnwire.QueryChannelRange, *lnwire.ReplyChannelRange, *lnwire.ReplyShortChanIDsEnd: discStream.AddMsg(msg) default: peerLog.Errorf("unknown message %v received from peer "+ "%v", uint16(msg.MsgType()), p) } if isChanUpdate { // If this is a channel update, then we need to feed it // into the channel's in-order message stream. chanStream, ok := chanMsgStreams[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) chanMsgStreams[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) } // 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("chan_id=%v, err=%v", msg.ChanID, string(msg.Data)) 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("complete=%v, encoding=%v, num_chans=%v", msg.Complete, msg.EncodingType, len(msg.ShortChanIDs)) 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, "+ "num_blocks=%v", msg.ChainHash, msg.FirstBlockHeight, msg.NumBlocks) 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 *peer) 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 the target lnwire.Message to the remote peer. func (p *peer) writeMessage(msg lnwire.Message) error { // Simply exit if we're shutting down. if atomic.LoadInt32(&p.disconnect) != 0 { return ErrPeerExiting } p.logWireMessage(msg, false) // We'll re-slice of static write buffer to allow this new message to // utilize all available space. We also ensure we cap the capacity of // this new buffer to the static buffer which is sized for the largest // possible protocol message. b := bytes.NewBuffer(p.writeBuf[0:0:len(p.writeBuf)]) // With the temp buffer created and sliced properly (length zero, full // capacity), we'll now encode the message directly into this buffer. _, err := lnwire.WriteMessage(b, msg, 0) if err != nil { return err } // Compute and set the write deadline we will impose on the remote peer. writeDeadline := time.Now().Add(writeMessageTimeout) err = p.conn.SetWriteDeadline(writeDeadline) if err != nil { return err } // Finally, write the message itself in a single swoop. n, err := p.conn.Write(b.Bytes()) // Regardless of the error returned, record how many bytes were written // to the wire. atomic.AddUint64(&p.bytesSent, uint64(n)) return err } // 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 *peer) writeHandler() { var exitErr error out: for { select { case outMsg := <-p.sendQueue: switch outMsg.msg.(type) { // 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. case *lnwire.Ping: // TODO(roasbeef): do this before the write? // possibly account for processing within func? now := time.Now().UnixNano() atomic.StoreInt64(&p.pingLastSend, now) } // Write out the message to the socket, responding with // error if `errChan` is non-nil. The `errChan` allows // callers to optionally synchronize sends with the // writeHandler. err := p.writeMessage(outMsg.msg) 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 = ErrPeerExiting break out } } 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 *peer) queueHandler() { defer p.wg.Done() // pendingMsgs will hold all messages waiting to be added // to the sendQueue. pendingMsgs := list.New() for { // Examine the front of the queue. elem := pendingMsgs.Front() if elem != nil { // 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 <- elem.Value.(outgoingMsg): pendingMsgs.Remove(elem) case msg := <-p.outgoingQueue: pendingMsgs.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: pendingMsgs.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 *peer) 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 *peer) PingTime() int64 { return atomic.LoadInt64(&p.pingTime) } // queueMsg queues a new lnwire.Message to be eventually sent out on the // wire. It returns an error if we failed to queue the message. An error // is sent on errChan if the message fails being sent to the peer, or // nil otherwise. func (p *peer) queueMsg(msg lnwire.Message, errChan chan error) { select { case p.outgoingQueue <- outgoingMsg{msg, errChan}: case <-p.quit: peerLog.Tracef("Peer shutting down, could not enqueue msg.") if errChan != nil { errChan <- ErrPeerExiting } } } // ChannelSnapshots returns a slice of channel snapshots detailing all // currently active channels maintained with the remote peer. func (p *peer) ChannelSnapshots() []*channeldb.ChannelSnapshot { p.activeChanMtx.RLock() defer p.activeChanMtx.RUnlock() snapshots := make([]*channeldb.ChannelSnapshot, 0, len(p.activeChannels)) for _, activeChan := range p.activeChannels { // 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 *peer) genDeliveryScript() ([]byte, error) { deliveryAddr, err := p.server.cc.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 *peer) channelManager() { defer p.wg.Done() 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) // Make sure this channel is not already active. p.activeChanMtx.Lock() if currentChan, ok := p.activeChannels[chanID]; ok { 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.server.cc.signer, p.server.witnessBeacon, newChan, p.server.sigPool, ) if err != nil { p.activeChanMtx.Unlock() err := fmt.Errorf("unable to create "+ "LightningChannel: %v", err) peerLog.Errorf(err.Error()) newChanReq.err <- err continue } p.activeChannels[chanID] = lnChan 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? _, currentHeight, err := p.server.cc.chainIO.GetBestBlock() if err != nil { err := fmt.Errorf("unable to get best "+ "block: %v", err) peerLog.Errorf(err.Error()) newChanReq.err <- err continue } chainEvents, err := p.server.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 fees we'll use the default values, as // they currently are always set to the default values // at initial channel creation. fwdMinHtlc := lnChan.FwdMinHtlc() defaultPolicy := p.server.cc.routingPolicy forwardingPolicy := &htlcswitch.ForwardingPolicy{ MinHTLC: fwdMinHtlc, BaseFee: defaultPolicy.BaseFee, FeeRate: defaultPolicy.FeeRate, TimeLockDelta: defaultPolicy.TimeLockDelta, } // Create the link and add it to the switch. err = p.addLink( chanPoint, lnChan, forwardingPolicy, chainEvents, currentHeight, false, ) 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. If 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: // We'll now fetch the matching closing state machine // in order to continue, or finalize the channel // closure process. chanCloser, err := p.fetchActiveChanCloser(closeMsg.cid) if err != nil { // If the channel is not known to us, we'll // simply ignore this message. if err == ErrChannelNotFound { continue } peerLog.Errorf("Unable to respond to remote "+ "close msg: %v", err) errMsg := &lnwire.Error{ ChanID: closeMsg.cid, Data: lnwire.ErrorData(err.Error()), } p.queueMsg(errMsg, nil) continue } // Next, we'll process the next message using the // target state machine. We'll either continue // negotiation, or halt. msgs, closeFin, err := chanCloser.ProcessCloseMsg( closeMsg.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 to ensure we act to on-chain // events as normal. chanCloser.cfg.channel.ResetState() if chanCloser.CloseRequest() != nil { chanCloser.CloseRequest().Err <- err } delete(p.activeChanCloses, closeMsg.cid) continue } // 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 { continue } // 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) 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 { channel.ResetState() } p.activeChanMtx.Unlock() break out } } } // 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 *peer) fetchActiveChanCloser(chanID lnwire.ChannelID) (*channelCloser, 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 !ok { 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. deliveryAddr, 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.server.cc.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.server.cc.chainIO.GetBestBlock() if err != nil { peerLog.Errorf("unable to obtain best block: %v", err) return nil, fmt.Errorf("cannot obtain best block") } chanCloser = newChannelCloser( chanCloseCfg{ channel: channel, unregisterChannel: p.server.htlcSwitch.RemoveLink, broadcastTx: p.server.cc.wallet.PublishTransaction, disableChannel: func(op wire.OutPoint) error { return p.server.announceChanStatus(op, true) }, quit: p.quit, }, deliveryAddr, feePerKw, uint32(startingHeight), nil, ) p.activeChanCloses[chanID] = chanCloser } return chanCloser, nil } // handleLocalCloseReq kicks-off the workflow to execute a cooperative or // forced unilateral closure of the channel initiated by a local subsystem. func (p *peer) handleLocalCloseReq(req *htlcswitch.ChanClose) { chanID := lnwire.NewChanIDFromOutPoint(req.ChanPoint) p.activeChanMtx.RLock() channel, ok := p.activeChannels[chanID] p.activeChanMtx.RUnlock() if !ok { 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 fetch a fresh delivery address that we'll use // to send the funds to in the case of a successful // negotiation. deliveryAddr, 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.server.cc.chainIO.GetBestBlock() if err != nil { peerLog.Errorf(err.Error()) req.Err <- err return } chanCloser := newChannelCloser( chanCloseCfg{ channel: channel, unregisterChannel: p.server.htlcSwitch.RemoveLink, broadcastTx: p.server.cc.wallet.PublishTransaction, disableChannel: func(op wire.OutPoint) error { return p.server.announceChanStatus(op, true) }, quit: p.quit, }, deliveryAddr, req.TargetFeePerKw, uint32(startingHeight), req, ) 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) if err := p.WipeChannel(req.ChanPoint); err != nil { peerLog.Infof("Unable to wipe channel after detected "+ "breach: %v", err) req.Err <- err return } return } } // linkFailureReport is sent to the channelManager whenever a link that was // added to the switch reports a link failure, and is forced to exit. The report // houses the necessary information to cleanup 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 handles facilitates 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 *peer) handleLinkFailure(failure linkFailureReport) { // 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. if err := p.WipeChannel(&failure.chanPoint); err != nil { peerLog.Errorf("Unable to wipe link for chanpoint=%v", failure.chanPoint) return } // If the error encountered was severe enough, we'll now force close the // channel to prevent readding it to the switch in the future. if failure.linkErr.ForceClose { peerLog.Warnf("Force closing link(%v)", failure.shortChanID) closeTx, err := p.server.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()) } } // 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 *peer) finalizeChanClosure(chanCloser *channelCloser) { closeReq := chanCloser.CloseRequest() // First, we'll clear all indexes related to the channel in question. chanPoint := chanCloser.cfg.channel.ChannelPoint() if err := p.WipeChannel(chanPoint); err != nil { if closeReq != nil { closeReq.Err <- err } } // 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.server.cc.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 *peer) WipeChannel(chanPoint *wire.OutPoint) error { 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.server.htlcSwitch.RemoveLink(chanID) return nil } // handleInitMsg handles the incoming init message which contains global and // local features vectors. If feature vectors are incompatible then disconnect. func (p *peer) handleInitMsg(msg *lnwire.Init) error { p.remoteLocalFeatures = lnwire.NewFeatureVector(msg.LocalFeatures, lnwire.LocalFeatures) p.remoteGlobalFeatures = lnwire.NewFeatureVector(msg.GlobalFeatures, lnwire.GlobalFeatures) unknownLocalFeatures := p.remoteLocalFeatures.UnknownRequiredFeatures() if len(unknownLocalFeatures) > 0 { err := fmt.Errorf("Peer set unknown local feature bits: %v", unknownLocalFeatures) return err } unknownGlobalFeatures := p.remoteGlobalFeatures.UnknownRequiredFeatures() if len(unknownGlobalFeatures) > 0 { err := fmt.Errorf("Peer set unknown global feature bits: %v", unknownGlobalFeatures) return err } return nil } // sendInitMsg sends init message to remote peer which contains our currently // supported local and global features. func (p *peer) sendInitMsg() error { msg := lnwire.NewInitMessage( p.server.globalFeatures.RawFeatureVector, p.localFeatures, ) 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 *peer) resendChanSyncMsg(cid lnwire.ChannelID) error { // Check if we have any channel sync messages stored for this channel. c, err := p.server.chanDB.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) } 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) return nil } // SendMessage sends a variadic number of message to remote peer. The first // argument denotes if the method should block until the message has been sent // to the remote peer. // // NOTE: Part of the lnpeer.Peer interface. func (p *peer) SendMessage(sync 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 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) } p.queueMsg(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 ErrPeerExiting } } return nil } // PubKey returns the pubkey of the peer in compressed serialized format. // // NOTE: Part of the lnpeer.Peer interface. func (p *peer) PubKey() [33]byte { return p.pubKeyBytes } // IdentityKey returns the public key of the remote peer. // // NOTE: Part of the lnpeer.Peer interface. func (p *peer) IdentityKey() *btcec.PublicKey { return p.addr.IdentityKey } // Address returns the network address of the remote peer. // // NOTE: Part of the lnpeer.Peer interface. func (p *peer) Address() net.Addr { return p.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 *peer) 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 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 ErrPeerExiting } } // StartTime returns the time at which the connection was established if the // peer started successfully, and zero otherwise. func (p *peer) StartTime() time.Time { return p.startTime } // TODO(roasbeef): make all start/stop mutexes a CAS