package main import ( "encoding/hex" "errors" "fmt" "net" "sync" "sync/atomic" "time" "github.com/btcsuite/fastsha256" "github.com/lightningnetwork/lightning-onion" "github.com/lightningnetwork/lnd/brontide" "github.com/lightningnetwork/lnd/chainntnfs" "github.com/lightningnetwork/lnd/channeldb" "github.com/lightningnetwork/lnd/lnrpc" "github.com/lightningnetwork/lnd/lnwallet" "github.com/lightningnetwork/lnd/lnwire" "github.com/lightningnetwork/lnd/routing" "github.com/roasbeef/btcd/btcec" "github.com/roasbeef/btcd/chaincfg/chainhash" "github.com/roasbeef/btcd/connmgr" "github.com/roasbeef/btcutil" ) // server is the main server of the Lightning Network Daemon. The server houses // global state pertaining to the wallet, database, and the rpcserver. // Additionally, the server is also used as a central messaging bus to interact // with any of its companion objects. type server struct { started int32 // atomic shutdown int32 // atomic // identityPriv is the private key used to authenticate any incoming // connections. identityPriv *btcec.PrivateKey // lightningID is the sha256 of the public key corresponding to our // long-term identity private key. lightningID [32]byte peersMtx sync.RWMutex peersByID map[int32]*peer peersByPub map[string]*peer rpcServer *rpcServer chainNotifier chainntnfs.ChainNotifier bio lnwallet.BlockChainIO lnwallet *lnwallet.LightningWallet fundingMgr *fundingManager chanDB *channeldb.DB htlcSwitch *htlcSwitch invoices *invoiceRegistry breachArbiter *breachArbiter chanRouter *routing.ChannelRouter utxoNursery *utxoNursery sphinx *sphinx.Router connMgr *connmgr.ConnManager pendingConnMtx sync.RWMutex persistentConnReqs map[string]*connmgr.ConnReq broadcastRequests chan *broadcastReq sendRequests chan *sendReq newPeers chan *peer donePeers chan *peer queries chan interface{} wg sync.WaitGroup quit chan struct{} } // newServer creates a new instance of the server which is to listen using the // passed listener address. func newServer(listenAddrs []string, notifier chainntnfs.ChainNotifier, bio lnwallet.BlockChainIO, wallet *lnwallet.LightningWallet, chanDB *channeldb.DB) (*server, error) { privKey, err := wallet.GetIdentitykey() if err != nil { return nil, err } privKey.Curve = btcec.S256() listeners := make([]net.Listener, len(listenAddrs)) for i, addr := range listenAddrs { listeners[i], err = brontide.NewListener(privKey, addr) if err != nil { return nil, err } } serializedPubKey := privKey.PubKey().SerializeCompressed() s := &server{ lnwallet: wallet, bio: bio, chainNotifier: notifier, chanDB: chanDB, invoices: newInvoiceRegistry(chanDB), utxoNursery: newUtxoNursery(chanDB, notifier, wallet), htlcSwitch: newHtlcSwitch(), identityPriv: privKey, // TODO(roasbeef): derive proper onion key based on rotation // schedule sphinx: sphinx.NewRouter(privKey, activeNetParams.Params), lightningID: fastsha256.Sum256(serializedPubKey), persistentConnReqs: make(map[string]*connmgr.ConnReq), peersByID: make(map[int32]*peer), peersByPub: make(map[string]*peer), newPeers: make(chan *peer, 10), donePeers: make(chan *peer, 10), broadcastRequests: make(chan *broadcastReq), sendRequests: make(chan *sendReq), queries: make(chan interface{}), quit: make(chan struct{}), } // If the debug HTLC flag is on, then we invoice a "master debug" // invoice which all outgoing payments will be sent and all incoming // HTLCs with the debug R-Hash immediately settled. if cfg.DebugHTLC { kiloCoin := btcutil.Amount(btcutil.SatoshiPerBitcoin * 1000) s.invoices.AddDebugInvoice(kiloCoin, *debugPre) srvrLog.Debugf("Debug HTLC invoice inserted, preimage=%x, hash=%x", debugPre[:], debugHash[:]) } // TODO(roasbeef): add --externalip flag? selfAddr, ok := listeners[0].Addr().(*net.TCPAddr) if !ok { return nil, fmt.Errorf("default listener must be TCP") } chanGraph := chanDB.ChannelGraph() self := &channeldb.LightningNode{ LastUpdate: time.Now(), Address: selfAddr, PubKey: privKey.PubKey(), // TODO(roasbeef): make alias configurable Alias: hex.EncodeToString(serializedPubKey[:10]), } if err := chanGraph.SetSourceNode(self); err != nil { return nil, err } s.chanRouter, err = routing.New(routing.Config{ Graph: chanGraph, Chain: bio, Notifier: notifier, Broadcast: s.broadcastMessage, SendMessages: s.sendToPeer, SendToSwitch: func(firstHop *btcec.PublicKey, htlcAdd *lnwire.HTLCAddRequest) error { firstHopPub := firstHop.SerializeCompressed() destInterface := chainhash.Hash(fastsha256.Sum256(firstHopPub)) return s.htlcSwitch.SendHTLC(&htlcPacket{ dest: destInterface, msg: htlcAdd, }) }, }) if err != nil { return nil, err } s.rpcServer = newRpcServer(s) s.breachArbiter = newBreachArbiter(wallet, chanDB, notifier, s.htlcSwitch) s.fundingMgr = newFundingManager(wallet, s.breachArbiter) // TODO(roasbeef): introduce closure and config system to decouple the // initialization above ^ // Create the connection manager which will be responsible for // maintaining persistent outbound connections and also accepting new // incoming connections cmgr, err := connmgr.New(&connmgr.Config{ Listeners: listeners, OnAccept: s.inboundPeerConnected, RetryDuration: time.Second * 5, TargetOutbound: 100, GetNewAddress: nil, Dial: noiseDial(s.identityPriv), OnConnection: s.outboundPeerConnected, }) if err != nil { return nil, err } s.connMgr = cmgr // In order to promote liveness of our active channels, instruct the // connection manager to attempt to establish and maintain persistent // connections to all our direct channel counterparties. linkNodes, err := s.chanDB.FetchAllLinkNodes() if err != nil && err != channeldb.ErrLinkNodesNotFound { return nil, err } for _, node := range linkNodes { // Create a wrapper address which couples the IP and the pubkey // so the brontide authenticated connection can be established. lnAddr := &lnwire.NetAddress{ IdentityKey: node.IdentityPub, Address: node.Addresses[0], } pubStr := string(node.IdentityPub.SerializeCompressed()) srvrLog.Debugf("Attempting persistent connection to channel "+ "peer %v", lnAddr) // Send the persistent connection request to the connection // manager, saving the request itself so we can cancel/restart // the process as needed. // TODO(roasbeef): use default addr connReq := &connmgr.ConnReq{ Addr: lnAddr, Permanent: true, } s.persistentConnReqs[pubStr] = connReq go s.connMgr.Connect(connReq) } return s, nil } // Start starts the main daemon server, all requested listeners, and any helper // goroutines. func (s *server) Start() error { // Already running? if atomic.AddInt32(&s.started, 1) != 1 { return nil } // Start the notification server. This is used so channel management // goroutines can be notified when a funding transaction reaches a // sufficient number of confirmations, or when the input for the // funding transaction is spent in an attempt at an uncooperative close // by the counterparty. if err := s.chainNotifier.Start(); err != nil { return err } if err := s.rpcServer.Start(); err != nil { return err } if err := s.fundingMgr.Start(); err != nil { return err } if err := s.htlcSwitch.Start(); err != nil { return err } if err := s.utxoNursery.Start(); err != nil { return err } if err := s.breachArbiter.Start(); err != nil { return err } if err := s.chanRouter.Start(); err != nil { return err } s.wg.Add(1) go s.queryHandler() return nil } // Stop gracefully shutsdown the main daemon server. This function will signal // any active goroutines, or helper objects to exit, then blocks until they've // all successfully exited. Additionally, any/all listeners are closed. func (s *server) Stop() error { // Bail if we're already shutting down. if atomic.AddInt32(&s.shutdown, 1) != 1 { return nil } // Shutdown the wallet, funding manager, and the rpc server. s.chainNotifier.Stop() s.rpcServer.Stop() s.fundingMgr.Stop() s.chanRouter.Stop() s.htlcSwitch.Stop() s.utxoNursery.Stop() s.breachArbiter.Stop() s.lnwallet.Shutdown() // Signal all the lingering goroutines to quit. close(s.quit) s.wg.Wait() return nil } // WaitForShutdown blocks all goroutines have been stopped. func (s *server) WaitForShutdown() { s.wg.Wait() } // broadcastReq is a message sent to the server by a related subsystem when it // wishes to broadcast one or more messages to all connected peers. Thi type broadcastReq struct { ignore *btcec.PublicKey msgs []lnwire.Message errChan chan error // MUST be buffered. } // broadcastMessage sends a request to the server to broadcast a set of // messages to all peers other than the one specified by the `skip` parameter. func (s *server) broadcastMessage(skip *btcec.PublicKey, msgs ...lnwire.Message) error { errChan := make(chan error, 1) msgsToSend := make([]lnwire.Message, 0, len(msgs)) msgsToSend = append(msgsToSend, msgs...) broadcastReq := &broadcastReq{ ignore: skip, msgs: msgsToSend, errChan: errChan, } select { case s.broadcastRequests <- broadcastReq: case <-s.quit: return errors.New("server shutting down") } select { case err := <-errChan: return err case <-s.quit: return errors.New("server shutting down") } } // sendReq is message sent to the server by a related subsystem which it // wishes to send a set of messages to a specified peer. type sendReq struct { target *btcec.PublicKey msgs []lnwire.Message errChan chan error } // sendToPeer send a message to the server telling it to send the specific set // of message to a particular peer. If the peer connect be found, then this // method will return a non-nil error. func (s *server) sendToPeer(target *btcec.PublicKey, msgs ...lnwire.Message) error { errChan := make(chan error, 1) msgsToSend := make([]lnwire.Message, 0, len(msgs)) msgsToSend = append(msgsToSend, msgs...) sMsg := &sendReq{ target: target, msgs: msgsToSend, errChan: errChan, } select { case s.sendRequests <- sMsg: case <-s.quit: return errors.New("server shutting down") } select { case err := <-errChan: return err case <-s.quit: return errors.New("server shutting down") } return nil } // peerConnected is a function that handles initialization a newly connected // peer by adding it to the server's global list of all active peers, and // starting all the goroutines the peer needs to function properly. func (s *server) peerConnected(conn net.Conn, connReq *connmgr.ConnReq, inbound bool) { brontideConn := conn.(*brontide.Conn) peerAddr := &lnwire.NetAddress{ IdentityKey: brontideConn.RemotePub(), Address: conn.RemoteAddr().(*net.TCPAddr), ChainNet: activeNetParams.Net, } // Now that we've established a connection, create a peer, and // it to the set of currently active peers. peer, err := newPeer(conn, s, peerAddr, false) if err != nil { srvrLog.Errorf("unable to create peer %v", err) conn.Close() return } if connReq != nil { peer.connReq = connReq } // TODO(roasbeef): update IP address for link-node // * also mark last-seen, do it one single transaction? peer.Start() s.newPeers <- peer } // inboundPeerConnected initializes a new peer in response to a new inbound // connection. func (s *server) inboundPeerConnected(conn net.Conn) { s.peersMtx.Lock() defer s.peersMtx.Unlock() srvrLog.Tracef("New inbound connection from %v", conn.RemoteAddr()) nodePub := conn.(*brontide.Conn).RemotePub() // If we already have an outbound connection to this peer, simply drop // the connection. pubStr := string(nodePub.SerializeCompressed()) if _, ok := s.peersByPub[pubStr]; ok { srvrLog.Errorf("Received inbound connection from peer %x, but "+ "already connected, dropping conn", nodePub.SerializeCompressed()) conn.Close() return } // However, if we receive an incoming connection from a peer we're // attempting to maintain a persistent connection with then we need to // cancel the ongoing connection attempts to ensure that we don't end // up with a duplicate connecting to the same peer. s.pendingConnMtx.RLock() if connReq, ok := s.persistentConnReqs[pubStr]; ok { s.connMgr.Remove(connReq.ID()) } s.pendingConnMtx.RUnlock() s.peerConnected(conn, nil, false) } // outboundPeerConnected initializes a new peer in response to a new outbound // connection. func (s *server) outboundPeerConnected(connReq *connmgr.ConnReq, conn net.Conn) { s.peersMtx.Lock() defer s.peersMtx.Unlock() srvrLog.Tracef("Established connection to: %v", conn.RemoteAddr()) nodePub := conn.(*brontide.Conn).RemotePub() // If we already have an inbound connection from this peer, simply drop // the connection. pubStr := string(nodePub.SerializeCompressed()) if _, ok := s.peersByPub[pubStr]; ok { srvrLog.Errorf("Established outbound connection to peer %x, but "+ "already connected, dropping conn", nodePub.SerializeCompressed()) s.connMgr.Remove(connReq.ID()) conn.Close() return } s.peerConnected(conn, connReq, true) } // addPeer adds the passed peer to the server's global state of all active // peers. func (s *server) addPeer(p *peer) { if p == nil { return } // Ignore new peers if we're shutting down. if atomic.LoadInt32(&s.shutdown) != 0 { p.Stop() return } // Track the new peer in our indexes so we can quickly look it up either // according to its public key, or it's peer ID. // TODO(roasbeef): pipe all requests through to the // queryHandler/peerManager s.peersMtx.Lock() s.peersByID[p.id] = p s.peersByPub[string(p.addr.IdentityKey.SerializeCompressed())] = p s.peersMtx.Unlock() // Once the peer has been added to our indexes, send a message to the // channel router so we can synchronize our view of the channel graph // with this new peer. s.chanRouter.SynchronizeNode(p.addr.IdentityKey) } // removePeer removes the passed peer from the server's state of all active // peers. func (s *server) removePeer(p *peer) { s.peersMtx.Lock() defer s.peersMtx.Unlock() srvrLog.Debugf("removing peer %v", p) if p == nil { return } // Ignore deleting peers if we're shutting down. if atomic.LoadInt32(&s.shutdown) != 0 { p.Stop() return } delete(s.peersByID, p.id) delete(s.peersByPub, string(p.addr.IdentityKey.SerializeCompressed())) } // connectPeerMsg is a message requesting the server to open a connection to a // particular peer. This message also houses an error channel which will be // used to report success/failure. type connectPeerMsg struct { addr *lnwire.NetAddress persistent bool err chan error } // listPeersMsg is a message sent to the server in order to obtain a listing // of all currently active channels. type listPeersMsg struct { resp chan []*peer } // openChanReq is a message sent to the server in order to request the // initiation of a channel funding workflow to the peer with either the specified // relative peer ID, or a global lightning ID. type openChanReq struct { targetPeerID int32 targetPubkey *btcec.PublicKey // TODO(roasbeef): make enums in lnwire channelType uint8 coinType uint64 localFundingAmt btcutil.Amount remoteFundingAmt btcutil.Amount pushAmt btcutil.Amount numConfs uint32 updates chan *lnrpc.OpenStatusUpdate err chan error } // queryHandler handles any requests to modify the server's internal state of // all active peers, or query/mutate the server's global state. Additionally, // any queries directed at peers will be handled by this goroutine. // // NOTE: This MUST be run as a goroutine. func (s *server) queryHandler() { go s.connMgr.Start() out: for { select { // New peers. case p := <-s.newPeers: s.addPeer(p) // Finished peers. case p := <-s.donePeers: s.removePeer(p) case bMsg := <-s.broadcastRequests: ignore := bMsg.ignore srvrLog.Debugf("Broadcasting %v messages", len(bMsg.msgs)) // Launch a new goroutine to handle the broadcast // request, this allows us process this request // asynchronously without blocking subsequent broadcast // requests. go func() { s.peersMtx.RLock() for _, sPeer := range s.peersByPub { if ignore != nil && sPeer.addr.IdentityKey.IsEqual(ignore) { srvrLog.Debugf("Skipping %v in broadcast", ignore.SerializeCompressed()) continue } go func(p *peer) { for _, msg := range bMsg.msgs { p.queueMsg(msg, nil) } }(sPeer) } s.peersMtx.RUnlock() bMsg.errChan <- nil }() case sMsg := <-s.sendRequests: // TODO(roasbeef): use [33]byte everywhere instead // * eliminate usage of mutexes, funnel all peer // mutation to this goroutine target := sMsg.target.SerializeCompressed() srvrLog.Debugf("Attempting to send msgs %v to: %x", len(sMsg.msgs), target) // Launch a new goroutine to handle this send request, // this allows us process this request asynchronously // without blocking future send requests. go func() { s.peersMtx.RLock() targetPeer, ok := s.peersByPub[string(target)] if !ok { s.peersMtx.RUnlock() srvrLog.Errorf("unable to send message to %x, "+ "peer not found", target) sMsg.errChan <- errors.New("peer not found") return } s.peersMtx.RUnlock() for _, msg := range sMsg.msgs { targetPeer.queueMsg(msg, nil) } sMsg.errChan <- nil }() case query := <-s.queries: switch msg := query.(type) { case *connectPeerMsg: s.handleConnectPeer(msg) case *listPeersMsg: s.handleListPeers(msg) case *openChanReq: s.handleOpenChanReq(msg) } case <-s.quit: break out } } s.connMgr.Stop() s.wg.Done() } // handleListPeers sends a lice of all currently active peers to the original // caller. func (s *server) handleListPeers(msg *listPeersMsg) { s.peersMtx.RLock() peers := make([]*peer, 0, len(s.peersByID)) for _, peer := range s.peersByID { peers = append(peers, peer) } s.peersMtx.RUnlock() msg.resp <- peers } // handleConnectPeer attempts to establish a connection to the address enclosed // within the passed connectPeerMsg. This function is *async*, a goroutine will // be spawned in order to finish the request, and respond to the caller. func (s *server) handleConnectPeer(msg *connectPeerMsg) { addr := msg.addr targetPub := string(msg.addr.IdentityKey.SerializeCompressed()) // Ensure we're not already connected to this // peer. s.peersMtx.RLock() peer, ok := s.peersByPub[targetPub] if ok { s.peersMtx.RUnlock() msg.err <- fmt.Errorf("already connected to peer: %v", peer) return } s.peersMtx.RUnlock() // If there's already a pending connection request for this pubkey, // then we ignore this request to ensure we don't create a redundant // connection. s.pendingConnMtx.RLock() if _, ok := s.persistentConnReqs[targetPub]; ok { s.pendingConnMtx.RUnlock() msg.err <- fmt.Errorf("connection attempt to %v is pending", addr) return } s.pendingConnMtx.RUnlock() // If there's not already a pending or active connection to this node, // then instruct the connection manager to attempt to establish a // persistent connection to the peer. srvrLog.Debugf("Connecting to %v", addr) if msg.persistent { go s.connMgr.Connect(&connmgr.ConnReq{ Addr: addr, Permanent: true, }) msg.err <- nil } else { // If we're not making a persistent connection, then we'll // attempt to connect o the target peer, returning an error // which indicates success of failure. go func() { // Attempt to connect to the remote node. If the we // can't make the connection, or the crypto negotiation // breaks down, then return an error to the caller. conn, err := brontide.Dial(s.identityPriv, addr) if err != nil { msg.err <- err return } s.outboundPeerConnected(nil, conn) msg.err <- nil }() } } // handleOpenChanReq first locates the target peer, and if found hands off the // request to the funding manager allowing it to initiate the channel funding // workflow. func (s *server) handleOpenChanReq(req *openChanReq) { var ( targetPeer *peer pubStr string ) // If the user is targeting the peer by public key, then we'll need to // convert that into a string for our map. Otherwise, we expect them to // target by peer ID instead. if req.targetPubkey != nil { pubStr = string(req.targetPubkey.SerializeCompressed()) } // First attempt to locate the target peer to open a channel with, if // we're unable to locate the peer then this request will fail. s.peersMtx.RLock() if peer, ok := s.peersByID[req.targetPeerID]; ok { targetPeer = peer } else if peer, ok := s.peersByPub[pubStr]; ok { targetPeer = peer } s.peersMtx.RUnlock() if targetPeer == nil { req.err <- fmt.Errorf("unable to find peer nodeID(%x), "+ "peerID(%v)", req.targetPubkey.SerializeCompressed(), req.targetPeerID) return } // Spawn a goroutine to send the funding workflow request to the funding // manager. This allows the server to continue handling queries instead // of blocking on this request which is exported as a synchronous // request to the outside world. // TODO(roasbeef): server semaphore to restrict num goroutines go s.fundingMgr.initFundingWorkflow(targetPeer, req) } // ConnectToPeer requests that the server connect to a Lightning Network peer // at the specified address. This function will *block* until either a // connection is established, or the initial handshake process fails. func (s *server) ConnectToPeer(addr *lnwire.NetAddress, perm bool) error { errChan := make(chan error, 1) s.queries <- &connectPeerMsg{ addr: addr, persistent: perm, err: errChan, } return <-errChan } // OpenChannel sends a request to the server to open a channel to the specified // peer identified by ID with the passed channel funding paramters. func (s *server) OpenChannel(peerID int32, nodeKey *btcec.PublicKey, localAmt, pushAmt btcutil.Amount, numConfs uint32) (chan *lnrpc.OpenStatusUpdate, chan error) { errChan := make(chan error, 1) updateChan := make(chan *lnrpc.OpenStatusUpdate, 1) req := &openChanReq{ targetPeerID: peerID, targetPubkey: nodeKey, localFundingAmt: localAmt, pushAmt: pushAmt, numConfs: numConfs, updates: updateChan, err: errChan, } s.queries <- req return updateChan, errChan } // Peers returns a slice of all active peers. func (s *server) Peers() []*peer { resp := make(chan []*peer, 1) s.queries <- &listPeersMsg{resp} return <-resp }