lnd.xprv/peer/brontide.go
eugene e0859e121f multi: add fmgr.Manager interface, change usage in peer to use Manager
This gets rid of several config functions in the peer and should pave
the way for easier testing of the funding manager and peer.
2020-10-01 10:27:13 -04:00

3015 lines
95 KiB
Go

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 generate 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 when creating a ChannelLink.
TowerClient 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 loop.
func (p *Brontide) 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 {
p.storeError(err)
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.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)
}
// 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)
}
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: p.cfg.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 his 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 dire 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 s
// 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
}
}
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. 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:
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 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) {
// 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 readding 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())
}
}
// 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() error {
msg := lnwire.NewInitMessage(
p.cfg.LegacyFeatures.RawFeatureVector,
p.cfg.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)
}