lnd.xprv/fundingmanager.go
2020-03-18 19:35:23 -07:00

3366 lines
115 KiB
Go

package lnd
import (
"bytes"
"encoding/binary"
"fmt"
"sync"
"time"
"github.com/btcsuite/btcd/btcec"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/txscript"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
"github.com/davecgh/go-spew/spew"
"github.com/go-errors/errors"
"github.com/lightningnetwork/lnd/chainntnfs"
"github.com/lightningnetwork/lnd/chanacceptor"
"github.com/lightningnetwork/lnd/channeldb"
"github.com/lightningnetwork/lnd/channeldb/kvdb"
"github.com/lightningnetwork/lnd/discovery"
"github.com/lightningnetwork/lnd/htlcswitch"
"github.com/lightningnetwork/lnd/input"
"github.com/lightningnetwork/lnd/keychain"
"github.com/lightningnetwork/lnd/lnpeer"
"github.com/lightningnetwork/lnd/lnrpc"
"github.com/lightningnetwork/lnd/lnwallet"
"github.com/lightningnetwork/lnd/lnwallet/chainfee"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/routing"
"golang.org/x/crypto/salsa20"
)
const (
// TODO(roasbeef): tune
msgBufferSize = 50
// minBtcRemoteDelay and maxBtcRemoteDelay is the extremes of the
// Bitcoin CSV delay we will require the remote to use for its
// commitment transaction. The actual delay we will require will be
// somewhere between these values, depending on channel size.
minBtcRemoteDelay uint16 = 144
maxBtcRemoteDelay uint16 = 2016
// minLtcRemoteDelay and maxLtcRemoteDelay is the extremes of the
// Litecoin CSV delay we will require the remote to use for its
// commitment transaction. The actual delay we will require will be
// somewhere between these values, depending on channel size.
minLtcRemoteDelay uint16 = 576
maxLtcRemoteDelay uint16 = 8064
// maxWaitNumBlocksFundingConf is the maximum number of blocks to wait
// for the funding transaction to be confirmed before forgetting
// channels that aren't initiated by us. 2016 blocks is ~2 weeks.
maxWaitNumBlocksFundingConf = 2016
// minChanFundingSize is the smallest channel that we'll allow to be
// created over the RPC interface.
minChanFundingSize = btcutil.Amount(20000)
// MaxBtcFundingAmount is a soft-limit of the maximum channel size
// currently accepted on the Bitcoin chain within the Lightning
// Protocol. This limit is defined in BOLT-0002, and serves as an
// initial precautionary limit while implementations are battle tested
// in the real world.
MaxBtcFundingAmount = btcutil.Amount(1<<24) - 1
// maxLtcFundingAmount is a soft-limit of the maximum channel size
// currently accepted on the Litecoin chain within the Lightning
// Protocol.
maxLtcFundingAmount = MaxBtcFundingAmount * btcToLtcConversionRate
)
var (
// MaxFundingAmount is a soft-limit of the maximum channel size
// currently accepted within the Lightning Protocol. This limit is
// defined in BOLT-0002, and serves as an initial precautionary limit
// while implementations are battle tested in the real world.
//
// At the moment, this value depends on which chain is active. It is set
// to the value under the Bitcoin chain as default.
//
// TODO(roasbeef): add command line param to modify
MaxFundingAmount = MaxBtcFundingAmount
// ErrFundingManagerShuttingDown is an error returned when attempting to
// process a funding request/message but the funding manager has already
// been signaled to shut down.
ErrFundingManagerShuttingDown = errors.New("funding manager shutting " +
"down")
// ErrConfirmationTimeout is an error returned when we as a responder
// are waiting for a funding transaction to confirm, but too many
// blocks pass without confirmation.
ErrConfirmationTimeout = errors.New("timeout waiting for funding " +
"confirmation")
// errUpfrontShutdownScriptNotSupported is returned if an upfront shutdown
// script is set for a peer that does not support the feature bit.
errUpfrontShutdownScriptNotSupported = errors.New("peer does not support" +
"option upfront shutdown script")
zeroID [32]byte
)
// reservationWithCtx encapsulates a pending channel reservation. This wrapper
// struct is used internally within the funding manager to track and progress
// the funding workflow initiated by incoming/outgoing methods from the target
// peer. Additionally, this struct houses a response and error channel which is
// used to respond to the caller in the case a channel workflow is initiated
// via a local signal such as RPC.
//
// TODO(roasbeef): actually use the context package
// * deadlines, etc.
type reservationWithCtx struct {
reservation *lnwallet.ChannelReservation
peer lnpeer.Peer
chanAmt btcutil.Amount
// Constraints we require for the remote.
remoteCsvDelay uint16
remoteMinHtlc lnwire.MilliSatoshi
updateMtx sync.RWMutex
lastUpdated time.Time
updates chan *lnrpc.OpenStatusUpdate
err chan error
}
// isLocked checks the reservation's timestamp to determine whether it is locked.
func (r *reservationWithCtx) isLocked() bool {
r.updateMtx.RLock()
defer r.updateMtx.RUnlock()
// The time zero value represents a locked reservation.
return r.lastUpdated.IsZero()
}
// updateTimestamp updates the reservation's timestamp with the current time.
func (r *reservationWithCtx) updateTimestamp() {
r.updateMtx.Lock()
defer r.updateMtx.Unlock()
r.lastUpdated = time.Now()
}
// initFundingMsg is sent by an outside subsystem to the funding manager in
// order to kick off a funding workflow with a specified target peer. The
// original request which defines the parameters of the funding workflow are
// embedded within this message giving the funding manager full context w.r.t
// the workflow.
type initFundingMsg struct {
peer lnpeer.Peer
*openChanReq
}
// fundingOpenMsg couples an lnwire.OpenChannel message with the peer who sent
// the message. This allows the funding manager to queue a response directly to
// the peer, progressing the funding workflow.
type fundingOpenMsg struct {
msg *lnwire.OpenChannel
peer lnpeer.Peer
}
// fundingAcceptMsg couples an lnwire.AcceptChannel message with the peer who
// sent the message. This allows the funding manager to queue a response
// directly to the peer, progressing the funding workflow.
type fundingAcceptMsg struct {
msg *lnwire.AcceptChannel
peer lnpeer.Peer
}
// fundingCreatedMsg couples an lnwire.FundingCreated message with the peer who
// sent the message. This allows the funding manager to queue a response
// directly to the peer, progressing the funding workflow.
type fundingCreatedMsg struct {
msg *lnwire.FundingCreated
peer lnpeer.Peer
}
// fundingSignedMsg couples an lnwire.FundingSigned message with the peer who
// sent the message. This allows the funding manager to queue a response
// directly to the peer, progressing the funding workflow.
type fundingSignedMsg struct {
msg *lnwire.FundingSigned
peer lnpeer.Peer
}
// fundingLockedMsg couples an lnwire.FundingLocked message with the peer who
// sent the message. This allows the funding manager to finalize the funding
// process and announce the existence of the new channel.
type fundingLockedMsg struct {
msg *lnwire.FundingLocked
peer lnpeer.Peer
}
// fundingErrorMsg couples an lnwire.Error message with the peer who sent the
// message. This allows the funding manager to properly process the error.
type fundingErrorMsg struct {
err *lnwire.Error
peerKey *btcec.PublicKey
}
// pendingChannels is a map instantiated per-peer which tracks all active
// pending single funded channels indexed by their pending channel identifier,
// which is a set of 32-bytes generated via a CSPRNG.
type pendingChannels map[[32]byte]*reservationWithCtx
// serializedPubKey is used within the FundingManager's activeReservations list
// to identify the nodes with which the FundingManager is actively working to
// initiate new channels.
type serializedPubKey [33]byte
// newSerializedKey creates a new serialized public key from an instance of a
// live pubkey object.
func newSerializedKey(pubKey *btcec.PublicKey) serializedPubKey {
var s serializedPubKey
copy(s[:], pubKey.SerializeCompressed())
return s
}
// fundingConfig defines the configuration for the FundingManager. All elements
// within the configuration MUST be non-nil for the FundingManager to carry out
// its duties.
type fundingConfig struct {
// IDKey is the PublicKey that is used to identify this node within the
// Lightning Network.
IDKey *btcec.PublicKey
// Wallet handles the parts of the funding process that involves moving
// funds from on-chain transaction outputs into Lightning channels.
Wallet *lnwallet.LightningWallet
// PublishTransaction facilitates the process of broadcasting a
// transaction to the network.
PublishTransaction func(*wire.MsgTx) error
// FeeEstimator calculates appropriate fee rates based on historical
// transaction information.
FeeEstimator chainfee.Estimator
// Notifier is used by the FundingManager to determine when the
// channel's funding transaction has been confirmed on the blockchain
// so that the channel creation process can be completed.
Notifier chainntnfs.ChainNotifier
// SignMessage signs an arbitrary message with a given public key. The
// actual digest signed is the double sha-256 of the message. In the
// case that the private key corresponding to the passed public key
// cannot be located, then an error is returned.
//
// TODO(roasbeef): should instead pass on this responsibility to a
// distinct sub-system?
SignMessage func(pubKey *btcec.PublicKey, msg []byte) (*btcec.Signature, error)
// CurrentNodeAnnouncement should return the latest, fully signed node
// announcement from the backing Lightning Network node.
CurrentNodeAnnouncement func() (lnwire.NodeAnnouncement, error)
// SendAnnouncement is used by the FundingManager to send announcement
// messages to the Gossiper to possibly broadcast to the greater
// network. A set of optional message fields can be provided to populate
// any information within the graph that is not included in the gossip
// message.
SendAnnouncement func(msg lnwire.Message,
optionalFields ...discovery.OptionalMsgField) chan error
// NotifyWhenOnline allows the FundingManager to register with a
// subsystem that will notify it when the peer comes online. This is
// used when sending the fundingLocked message, since it MUST be
// delivered after the funding transaction is confirmed.
//
// NOTE: The peerChan channel must be buffered.
NotifyWhenOnline func(peer [33]byte, peerChan chan<- lnpeer.Peer)
// FindChannel queries the database for the channel with the given
// channel ID.
FindChannel func(chanID lnwire.ChannelID) (*channeldb.OpenChannel, error)
// TempChanIDSeed is a cryptographically random string of bytes that's
// used as a seed to generate pending channel ID's.
TempChanIDSeed [32]byte
// DefaultRoutingPolicy is the default routing policy used when
// initially announcing channels.
DefaultRoutingPolicy htlcswitch.ForwardingPolicy
// DefaultMinHtlcIn is the default minimum incoming htlc value that is
// set as a channel parameter.
DefaultMinHtlcIn lnwire.MilliSatoshi
// NumRequiredConfs is a function closure that helps the funding
// manager decide how many confirmations it should require for a
// channel extended to it. The function is able to take into account
// the amount of the channel, and any funds we'll be pushed in the
// process to determine how many confirmations we'll require.
NumRequiredConfs func(btcutil.Amount, lnwire.MilliSatoshi) uint16
// RequiredRemoteDelay is a function that maps the total amount in a
// proposed channel to the CSV delay that we'll require for the remote
// party. Naturally a larger channel should require a higher CSV delay
// in order to give us more time to claim funds in the case of a
// contract breach.
RequiredRemoteDelay func(btcutil.Amount) uint16
// RequiredRemoteChanReserve is a function closure that, given the
// channel capacity and dust limit, will return an appropriate amount
// for the remote peer's required channel reserve that is to be adhered
// to at all times.
RequiredRemoteChanReserve func(capacity, dustLimit btcutil.Amount) btcutil.Amount
// RequiredRemoteMaxValue is a function closure that, given the channel
// capacity, returns the amount of MilliSatoshis that our remote peer
// can have in total outstanding HTLCs with us.
RequiredRemoteMaxValue func(btcutil.Amount) lnwire.MilliSatoshi
// RequiredRemoteMaxHTLCs is a function closure that, given the channel
// capacity, returns the number of maximum HTLCs the remote peer can
// offer us.
RequiredRemoteMaxHTLCs func(btcutil.Amount) uint16
// WatchNewChannel is to be called once a new channel enters the final
// funding stage: waiting for on-chain confirmation. This method sends
// the channel to the ChainArbitrator so it can watch for any on-chain
// events related to the channel. We also provide the public key of the
// node we're establishing a channel with for reconnection purposes.
WatchNewChannel func(*channeldb.OpenChannel, *btcec.PublicKey) error
// ReportShortChanID allows the funding manager to report the newly
// discovered short channel ID of a formerly pending channel to outside
// sub-systems.
ReportShortChanID func(wire.OutPoint) error
// ZombieSweeperInterval is the periodic time interval in which the
// zombie sweeper is run.
ZombieSweeperInterval time.Duration
// ReservationTimeout is the length of idle time that must pass before
// a reservation is considered a zombie.
ReservationTimeout time.Duration
// MinChanSize is the smallest channel size that we'll accept as an
// inbound channel. We have such a parameter, as otherwise, nodes could
// flood us with very small channels that would never really be usable
// due to fees.
MinChanSize btcutil.Amount
// MaxPendingChannels is the maximum number of pending channels we
// allow for each peer.
MaxPendingChannels int
// RejectPush is set true if the fundingmanager should reject any
// incoming channels having a non-zero push amount.
RejectPush bool
// NotifyOpenChannelEvent informs the ChannelNotifier when channels
// transition from pending open to open.
NotifyOpenChannelEvent func(wire.OutPoint)
// OpenChannelPredicate is a predicate on the lnwire.OpenChannel message
// and on the requesting node's public key that returns a bool which tells
// the funding manager whether or not to accept the channel.
OpenChannelPredicate chanacceptor.ChannelAcceptor
// NotifyPendingOpenChannelEvent informs the ChannelNotifier when channels
// enter a pending state.
NotifyPendingOpenChannelEvent func(wire.OutPoint, *channeldb.OpenChannel)
}
// fundingManager acts as an orchestrator/bridge between the wallet's
// 'ChannelReservation' workflow, and the wire protocol's funding initiation
// messages. Any requests to initiate the funding workflow for a channel,
// either kicked-off locally or remotely are handled by the funding manager.
// Once a channel's funding workflow has been completed, any local callers, the
// local peer, and possibly the remote peer are notified of the completion of
// the channel workflow. Additionally, any temporary or permanent access
// controls between the wallet and remote peers are enforced via the funding
// manager.
type fundingManager struct {
started sync.Once
stopped sync.Once
// cfg is a copy of the configuration struct that the FundingManager
// was initialized with.
cfg *fundingConfig
// chanIDKey is a cryptographically random key that's used to generate
// temporary channel ID's.
chanIDKey [32]byte
// chanIDNonce is a nonce that's incremented for each new funding
// reservation created.
nonceMtx sync.RWMutex
chanIDNonce uint64
// activeReservations is a map which houses the state of all pending
// funding workflows.
activeReservations map[serializedPubKey]pendingChannels
// signedReservations is a utility map that maps the permanent channel
// ID of a funding reservation to its temporary channel ID. This is
// required as mid funding flow, we switch to referencing the channel
// by its full channel ID once the commitment transactions have been
// signed by both parties.
signedReservations map[lnwire.ChannelID][32]byte
// resMtx guards both of the maps above to ensure that all access is
// goroutine safe.
resMtx sync.RWMutex
// fundingMsgs is a channel which receives wrapped wire messages
// related to funding workflow from outside peers.
fundingMsgs chan interface{}
// queries is a channel which receives requests to query the internal
// state of the funding manager.
queries chan interface{}
// fundingRequests is a channel used to receive channel initiation
// requests from a local subsystem within the daemon.
fundingRequests chan *initFundingMsg
// newChanBarriers is a map from a channel ID to a 'barrier' which will
// be signalled once the channel is fully open. This barrier acts as a
// synchronization point for any incoming/outgoing HTLCs before the
// channel has been fully opened.
barrierMtx sync.RWMutex
newChanBarriers map[lnwire.ChannelID]chan struct{}
localDiscoveryMtx sync.Mutex
localDiscoverySignals map[lnwire.ChannelID]chan struct{}
handleFundingLockedMtx sync.RWMutex
handleFundingLockedBarriers map[lnwire.ChannelID]struct{}
quit chan struct{}
wg sync.WaitGroup
}
// channelOpeningState represents the different states a channel can be in
// between the funding transaction has been confirmed and the channel is
// announced to the network and ready to be used.
type channelOpeningState uint8
const (
// markedOpen is the opening state of a channel if the funding
// transaction is confirmed on-chain, but fundingLocked is not yet
// successfully sent to the other peer.
markedOpen channelOpeningState = iota
// fundingLockedSent is the opening state of a channel if the
// fundingLocked message has successfully been sent to the other peer,
// but we still haven't announced the channel to the network.
fundingLockedSent
// addedToRouterGraph is the opening state of a channel if the
// channel has been successfully added to the router graph
// immediately after the fundingLocked message has been sent, but
// we still haven't announced the channel to the network.
addedToRouterGraph
)
var (
// channelOpeningStateBucket is the database bucket used to store the
// channelOpeningState for each channel that is currently in the process
// of being opened.
channelOpeningStateBucket = []byte("channelOpeningState")
// ErrChannelNotFound is an error returned when a channel is not known
// to us. In this case of the fundingManager, this error is returned
// when the channel in question is not considered being in an opening
// state.
ErrChannelNotFound = fmt.Errorf("channel not found")
)
// newFundingManager creates and initializes a new instance of the
// fundingManager.
func newFundingManager(cfg fundingConfig) (*fundingManager, error) {
return &fundingManager{
cfg: &cfg,
chanIDKey: cfg.TempChanIDSeed,
activeReservations: make(map[serializedPubKey]pendingChannels),
signedReservations: make(map[lnwire.ChannelID][32]byte),
newChanBarriers: make(map[lnwire.ChannelID]chan struct{}),
fundingMsgs: make(chan interface{}, msgBufferSize),
fundingRequests: make(chan *initFundingMsg, msgBufferSize),
localDiscoverySignals: make(map[lnwire.ChannelID]chan struct{}),
handleFundingLockedBarriers: make(map[lnwire.ChannelID]struct{}),
queries: make(chan interface{}, 1),
quit: make(chan struct{}),
}, nil
}
// Start launches all helper goroutines required for handling requests sent
// to the funding manager.
func (f *fundingManager) Start() error {
var err error
f.started.Do(func() {
err = f.start()
})
return err
}
func (f *fundingManager) start() error {
fndgLog.Tracef("Funding manager running")
// Upon restart, the Funding Manager will check the database to load any
// channels that were waiting for their funding transactions to be
// confirmed on the blockchain at the time when the daemon last went
// down.
// TODO(roasbeef): store height that funding finished?
// * would then replace call below
allChannels, err := f.cfg.Wallet.Cfg.Database.FetchAllChannels()
if err != nil {
return err
}
for _, channel := range allChannels {
chanID := lnwire.NewChanIDFromOutPoint(&channel.FundingOutpoint)
// For any channels that were in a pending state when the
// daemon was last connected, the Funding Manager will
// re-initialize the channel barriers, and republish the
// funding transaction if we're the initiator.
if channel.IsPending {
f.barrierMtx.Lock()
fndgLog.Tracef("Loading pending ChannelPoint(%v), "+
"creating chan barrier",
channel.FundingOutpoint)
f.newChanBarriers[chanID] = make(chan struct{})
f.barrierMtx.Unlock()
f.localDiscoverySignals[chanID] = make(chan struct{})
// Rebroadcast the funding transaction for any pending
// channel that we initiated. No error will be returned
// if the transaction already has been broadcast.
chanType := channel.ChanType
if chanType.IsSingleFunder() && chanType.HasFundingTx() &&
channel.IsInitiator {
err := f.cfg.PublishTransaction(
channel.FundingTxn,
)
if err != nil {
fndgLog.Errorf("Unable to rebroadcast "+
"funding tx for "+
"ChannelPoint(%v): %v",
channel.FundingOutpoint, err)
}
}
}
// We will restart the funding state machine for all channels,
// which will wait for the channel's funding transaction to be
// confirmed on the blockchain, and transmit the messages
// necessary for the channel to be operational.
f.wg.Add(1)
go f.advanceFundingState(channel, chanID, nil)
}
f.wg.Add(1) // TODO(roasbeef): tune
go f.reservationCoordinator()
return nil
}
// Stop signals all helper goroutines to execute a graceful shutdown. This
// method will block until all goroutines have exited.
func (f *fundingManager) Stop() error {
var err error
f.stopped.Do(func() {
err = f.stop()
})
return err
}
func (f *fundingManager) stop() error {
fndgLog.Infof("Funding manager shutting down")
close(f.quit)
f.wg.Wait()
return nil
}
// nextPendingChanID returns the next free pending channel ID to be used to
// identify a particular future channel funding workflow.
func (f *fundingManager) nextPendingChanID() [32]byte {
// Obtain a fresh nonce. We do this by encoding the current nonce
// counter, then incrementing it by one.
f.nonceMtx.Lock()
var nonce [8]byte
binary.LittleEndian.PutUint64(nonce[:], f.chanIDNonce)
f.chanIDNonce++
f.nonceMtx.Unlock()
// We'll generate the next pending channelID by "encrypting" 32-bytes
// of zeroes which'll extract 32 random bytes from our stream cipher.
var (
nextChanID [32]byte
zeroes [32]byte
)
salsa20.XORKeyStream(nextChanID[:], zeroes[:], nonce[:], &f.chanIDKey)
return nextChanID
}
type pendingChannel struct {
identityPub *btcec.PublicKey
channelPoint *wire.OutPoint
capacity btcutil.Amount
localBalance btcutil.Amount
remoteBalance btcutil.Amount
}
type pendingChansReq struct {
resp chan []*pendingChannel
err chan error
}
// PendingChannels returns a slice describing all the channels which are
// currently pending at the last state of the funding workflow.
func (f *fundingManager) PendingChannels() ([]*pendingChannel, error) {
respChan := make(chan []*pendingChannel, 1)
errChan := make(chan error, 1)
req := &pendingChansReq{
resp: respChan,
err: errChan,
}
select {
case f.queries <- req:
case <-f.quit:
return nil, ErrFundingManagerShuttingDown
}
select {
case resp := <-respChan:
return resp, nil
case err := <-errChan:
return nil, err
case <-f.quit:
return nil, ErrFundingManagerShuttingDown
}
}
// CancelPeerReservations cancels all active reservations associated with the
// passed node. This will ensure any outputs which have been pre committed,
// (and thus locked from coin selection), are properly freed.
func (f *fundingManager) CancelPeerReservations(nodePub [33]byte) {
fndgLog.Debugf("Cancelling all reservations for peer %x", nodePub[:])
f.resMtx.Lock()
defer f.resMtx.Unlock()
// We'll attempt to look up this node in the set of active
// reservations. If they don't have any, then there's no further work
// to be done.
nodeReservations, ok := f.activeReservations[nodePub]
if !ok {
fndgLog.Debugf("No active reservations for node: %x", nodePub[:])
return
}
// If they do have any active reservations, then we'll cancel all of
// them (which releases any locked UTXO's), and also delete it from the
// reservation map.
for pendingID, resCtx := range nodeReservations {
if err := resCtx.reservation.Cancel(); err != nil {
fndgLog.Errorf("unable to cancel reservation for "+
"node=%x: %v", nodePub[:], err)
}
resCtx.err <- fmt.Errorf("peer disconnected")
delete(nodeReservations, pendingID)
}
// Finally, we'll delete the node itself from the set of reservations.
delete(f.activeReservations, nodePub)
}
// failFundingFlow will fail the active funding flow with the target peer,
// identified by its unique temporary channel ID. This method will send an
// error to the remote peer, and also remove the reservation from our set of
// pending reservations.
//
// TODO(roasbeef): if peer disconnects, and haven't yet broadcast funding
// transaction, then all reservations should be cleared.
func (f *fundingManager) failFundingFlow(peer lnpeer.Peer, tempChanID [32]byte,
fundingErr error) {
fndgLog.Debugf("Failing funding flow for pending_id=%x: %v",
tempChanID, fundingErr)
ctx, err := f.cancelReservationCtx(peer.IdentityKey(), tempChanID)
if err != nil {
fndgLog.Errorf("unable to cancel reservation: %v", err)
}
// In case the case where the reservation existed, send the funding
// error on the error channel.
if ctx != nil {
ctx.err <- fundingErr
}
// We only send the exact error if it is part of out whitelisted set of
// errors (lnwire.FundingError or lnwallet.ReservationError).
var msg lnwire.ErrorData
switch e := fundingErr.(type) {
// Let the actual error message be sent to the remote for the
// whitelisted types.
case lnwallet.ReservationError:
msg = lnwire.ErrorData(e.Error())
case lnwire.FundingError:
msg = lnwire.ErrorData(e.Error())
// For all other error types we just send a generic error.
default:
msg = lnwire.ErrorData("funding failed due to internal error")
}
errMsg := &lnwire.Error{
ChanID: tempChanID,
Data: msg,
}
fndgLog.Debugf("Sending funding error to peer (%x): %v",
peer.IdentityKey().SerializeCompressed(), spew.Sdump(errMsg))
if err := peer.SendMessage(false, errMsg); err != nil {
fndgLog.Errorf("unable to send error message to peer %v", err)
}
}
// reservationCoordinator is the primary goroutine tasked with progressing the
// funding workflow between the wallet, and any outside peers or local callers.
//
// NOTE: This MUST be run as a goroutine.
func (f *fundingManager) reservationCoordinator() {
defer f.wg.Done()
zombieSweepTicker := time.NewTicker(f.cfg.ZombieSweeperInterval)
defer zombieSweepTicker.Stop()
for {
select {
case msg := <-f.fundingMsgs:
switch fmsg := msg.(type) {
case *fundingOpenMsg:
f.handleFundingOpen(fmsg)
case *fundingAcceptMsg:
f.handleFundingAccept(fmsg)
case *fundingCreatedMsg:
f.handleFundingCreated(fmsg)
case *fundingSignedMsg:
f.handleFundingSigned(fmsg)
case *fundingLockedMsg:
f.wg.Add(1)
go f.handleFundingLocked(fmsg)
case *fundingErrorMsg:
f.handleErrorMsg(fmsg)
}
case req := <-f.fundingRequests:
f.handleInitFundingMsg(req)
case <-zombieSweepTicker.C:
f.pruneZombieReservations()
case req := <-f.queries:
switch msg := req.(type) {
case *pendingChansReq:
f.handlePendingChannels(msg)
}
case <-f.quit:
return
}
}
}
// advanceFundingState will advance the channel through the steps after the
// funding transaction is broadcasted, up until the point where the channel is
// ready for operation. This includes waiting for the funding transaction to
// confirm, sending funding locked to the peer, adding the channel to the
// router graph, and announcing the channel. The updateChan can be set non-nil
// to get OpenStatusUpdates.
//
// NOTE: This MUST be run as a goroutine.
func (f *fundingManager) advanceFundingState(channel *channeldb.OpenChannel,
pendingChanID [32]byte, updateChan chan<- *lnrpc.OpenStatusUpdate) {
defer f.wg.Done()
// If the channel is still pending we must wait for the funding
// transaction to confirm.
if channel.IsPending {
err := f.advancePendingChannelState(channel, pendingChanID)
if err != nil {
fndgLog.Errorf("Unable to advance pending state of "+
"ChannelPoint(%v): %v",
channel.FundingOutpoint, err)
return
}
}
// We create the state-machine object which wraps the database state.
lnChannel, err := lnwallet.NewLightningChannel(
nil, channel, nil,
)
if err != nil {
fndgLog.Errorf("Unable to create LightningChannel(%v): %v",
channel.FundingOutpoint, err)
return
}
for {
channelState, shortChanID, err := f.getChannelOpeningState(
&channel.FundingOutpoint,
)
if err == ErrChannelNotFound {
// Channel not in fundingManager's opening database,
// meaning it was successfully announced to the
// network.
// TODO(halseth): could do graph consistency check
// here, and re-add the edge if missing.
fndgLog.Debugf("ChannelPoint(%v) with chan_id=%x not "+
"found in opening database, assuming already "+
"announced to the network",
channel.FundingOutpoint, pendingChanID)
return
} else if err != nil {
fndgLog.Errorf("Unable to query database for "+
"channel opening state(%v): %v",
channel.FundingOutpoint, err)
return
}
// If we did find the channel in the opening state database, we
// have seen the funding transaction being confirmed, but there
// are still steps left of the setup procedure. We continue the
// procedure where we left off.
err = f.stateStep(
channel, lnChannel, shortChanID, pendingChanID,
channelState, updateChan,
)
if err != nil {
fndgLog.Errorf("Unable to advance state(%v): %v",
channel.FundingOutpoint, err)
return
}
}
}
// stateStep advances the confirmed channel one step in the funding state
// machine. This method is synchronous and the new channel opening state will
// have been written to the database when it successfully returns. The
// updateChan can be set non-nil to get OpenStatusUpdates.
func (f *fundingManager) stateStep(channel *channeldb.OpenChannel,
lnChannel *lnwallet.LightningChannel,
shortChanID *lnwire.ShortChannelID, pendingChanID [32]byte,
channelState channelOpeningState,
updateChan chan<- *lnrpc.OpenStatusUpdate) error {
chanID := lnwire.NewChanIDFromOutPoint(&channel.FundingOutpoint)
fndgLog.Debugf("Channel(%v) with ShortChanID %v has opening state %v",
chanID, shortChanID, channelState)
switch channelState {
// The funding transaction was confirmed, but we did not successfully
// send the fundingLocked message to the peer, so let's do that now.
case markedOpen:
err := f.sendFundingLocked(channel, lnChannel, shortChanID)
if err != nil {
return fmt.Errorf("failed sending fundingLocked: %v",
err)
}
// As the fundingLocked message is now sent to the peer, the
// channel is moved to the next state of the state machine. It
// will be moved to the last state (actually deleted from the
// database) after the channel is finally announced.
err = f.saveChannelOpeningState(
&channel.FundingOutpoint, fundingLockedSent,
shortChanID,
)
if err != nil {
return fmt.Errorf("error setting channel state to"+
" fundingLockedSent: %v", err)
}
fndgLog.Debugf("Channel(%v) with ShortChanID %v: successfully "+
"sent FundingLocked", chanID, shortChanID)
return nil
// fundingLocked was sent to peer, but the channel was not added to the
// router graph and the channel announcement was not sent.
case fundingLockedSent:
err := f.addToRouterGraph(channel, shortChanID)
if err != nil {
return fmt.Errorf("failed adding to "+
"router graph: %v", err)
}
// As the channel is now added to the ChannelRouter's topology,
// the channel is moved to the next state of the state machine.
// It will be moved to the last state (actually deleted from
// the database) after the channel is finally announced.
err = f.saveChannelOpeningState(
&channel.FundingOutpoint, addedToRouterGraph,
shortChanID,
)
if err != nil {
return fmt.Errorf("error setting channel state to"+
" addedToRouterGraph: %v", err)
}
fndgLog.Debugf("Channel(%v) with ShortChanID %v: successfully "+
"added to router graph", chanID, shortChanID)
// Give the caller a final update notifying them that
// the channel is now open.
// TODO(roasbeef): only notify after recv of funding locked?
fundingPoint := channel.FundingOutpoint
cp := &lnrpc.ChannelPoint{
FundingTxid: &lnrpc.ChannelPoint_FundingTxidBytes{
FundingTxidBytes: fundingPoint.Hash[:],
},
OutputIndex: fundingPoint.Index,
}
if updateChan != nil {
upd := &lnrpc.OpenStatusUpdate{
Update: &lnrpc.OpenStatusUpdate_ChanOpen{
ChanOpen: &lnrpc.ChannelOpenUpdate{
ChannelPoint: cp,
},
},
PendingChanId: pendingChanID[:],
}
select {
case updateChan <- upd:
case <-f.quit:
return ErrFundingManagerShuttingDown
}
}
return nil
// The channel was added to the Router's topology, but the channel
// announcement was not sent.
case addedToRouterGraph:
err := f.annAfterSixConfs(channel, shortChanID)
if err != nil {
return fmt.Errorf("error sending channel "+
"announcement: %v", err)
}
// We delete the channel opening state from our internal
// database as the opening process has succeeded. We can do
// this because we assume the AuthenticatedGossiper queues the
// announcement messages, and persists them in case of a daemon
// shutdown.
err = f.deleteChannelOpeningState(&channel.FundingOutpoint)
if err != nil {
return fmt.Errorf("error deleting channel state: %v",
err)
}
fndgLog.Debugf("Channel(%v) with ShortChanID %v: successfully "+
"announced", chanID, shortChanID)
return nil
}
return fmt.Errorf("undefined channelState: %v", channelState)
}
// advancePendingChannelState waits for a pending channel's funding tx to
// confirm, and marks it open in the database when that happens.
func (f *fundingManager) advancePendingChannelState(
channel *channeldb.OpenChannel, pendingChanID [32]byte) error {
confChannel, err := f.waitForFundingWithTimeout(channel)
if err == ErrConfirmationTimeout {
// We'll get a timeout if the number of blocks mined
// since the channel was initiated reaches
// maxWaitNumBlocksFundingConf and we are not the
// channel initiator.
ch := channel
localBalance := ch.LocalCommitment.LocalBalance.ToSatoshis()
closeInfo := &channeldb.ChannelCloseSummary{
ChainHash: ch.ChainHash,
ChanPoint: ch.FundingOutpoint,
RemotePub: ch.IdentityPub,
Capacity: ch.Capacity,
SettledBalance: localBalance,
CloseType: channeldb.FundingCanceled,
RemoteCurrentRevocation: ch.RemoteCurrentRevocation,
RemoteNextRevocation: ch.RemoteNextRevocation,
LocalChanConfig: ch.LocalChanCfg,
}
// Close the channel with us as the initiator because we are
// timing the channel out.
if err := ch.CloseChannel(
closeInfo, channeldb.ChanStatusLocalCloseInitiator,
); err != nil {
return fmt.Errorf("failed closing channel "+
"%v: %v", ch.FundingOutpoint, err)
}
timeoutErr := fmt.Errorf("timeout waiting for funding tx "+
"(%v) to confirm", channel.FundingOutpoint)
// When the peer comes online, we'll notify it that we
// are now considering the channel flow canceled.
f.wg.Add(1)
go func() {
defer f.wg.Done()
peerChan := make(chan lnpeer.Peer, 1)
var peerKey [33]byte
copy(peerKey[:], ch.IdentityPub.SerializeCompressed())
f.cfg.NotifyWhenOnline(peerKey, peerChan)
var peer lnpeer.Peer
select {
case peer = <-peerChan:
case <-f.quit:
return
}
// TODO(halseth): should this send be made
// reliable?
f.failFundingFlow(peer, pendingChanID, timeoutErr)
}()
return timeoutErr
} else if err != nil {
return fmt.Errorf("error waiting for funding "+
"confirmation for ChannelPoint(%v): %v",
channel.FundingOutpoint, err)
}
// Success, funding transaction was confirmed.
chanID := lnwire.NewChanIDFromOutPoint(&channel.FundingOutpoint)
fndgLog.Debugf("ChannelID(%v) is now fully confirmed! "+
"(shortChanID=%v)", chanID, confChannel.shortChanID)
err = f.handleFundingConfirmation(channel, confChannel)
if err != nil {
return fmt.Errorf("unable to handle funding "+
"confirmation for ChannelPoint(%v): %v",
channel.FundingOutpoint, err)
}
return nil
}
// handlePendingChannels responds to a request for details concerning all
// currently pending channels waiting for the final phase of the funding
// workflow (funding txn confirmation).
func (f *fundingManager) handlePendingChannels(msg *pendingChansReq) {
var pendingChannels []*pendingChannel
dbPendingChannels, err := f.cfg.Wallet.Cfg.Database.FetchPendingChannels()
if err != nil {
msg.err <- err
return
}
for _, dbPendingChan := range dbPendingChannels {
pendingChan := &pendingChannel{
identityPub: dbPendingChan.IdentityPub,
channelPoint: &dbPendingChan.FundingOutpoint,
capacity: dbPendingChan.Capacity,
localBalance: dbPendingChan.LocalCommitment.LocalBalance.ToSatoshis(),
remoteBalance: dbPendingChan.LocalCommitment.RemoteBalance.ToSatoshis(),
}
pendingChannels = append(pendingChannels, pendingChan)
}
msg.resp <- pendingChannels
}
// processFundingOpen sends a message to the fundingManager allowing it to
// initiate the new funding workflow with the source peer.
func (f *fundingManager) processFundingOpen(msg *lnwire.OpenChannel,
peer lnpeer.Peer) {
select {
case f.fundingMsgs <- &fundingOpenMsg{msg, peer}:
case <-f.quit:
return
}
}
// commitmentType returns the commitment type to use for the channel, based on
// the features the two peers have available.
func commitmentType(localFeatures,
remoteFeatures *lnwire.FeatureVector) lnwallet.CommitmentType {
// If both peers are signalling support for anchor commitments, this
// implicitly mean we'll create the channel of this type. Note that
// this also enables tweakless commitments, as anchor commitments are
// always tweakless.
localAnchors := localFeatures.HasFeature(
lnwire.AnchorsOptional,
)
remoteAnchors := remoteFeatures.HasFeature(
lnwire.AnchorsOptional,
)
if localAnchors && remoteAnchors {
return lnwallet.CommitmentTypeAnchors
}
localTweakless := localFeatures.HasFeature(
lnwire.StaticRemoteKeyOptional,
)
remoteTweakless := remoteFeatures.HasFeature(
lnwire.StaticRemoteKeyOptional,
)
// If both nodes are signaling the proper feature bit for tweakless
// copmmitments, we'll use that.
if localTweakless && remoteTweakless {
return lnwallet.CommitmentTypeTweakless
}
// Otherwise we'll fall back to the legacy type.
return lnwallet.CommitmentTypeLegacy
}
// handleFundingOpen creates an initial 'ChannelReservation' within the wallet,
// then responds to the source peer with an accept channel message progressing
// the funding workflow.
//
// TODO(roasbeef): add error chan to all, let channelManager handle
// error+propagate
func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
// Check number of pending channels to be smaller than maximum allowed
// number and send ErrorGeneric to remote peer if condition is
// violated.
peerPubKey := fmsg.peer.IdentityKey()
peerIDKey := newSerializedKey(peerPubKey)
msg := fmsg.msg
amt := msg.FundingAmount
// We count the number of pending channels for this peer. This is the
// sum of the active reservations and the channels pending open in the
// database.
f.resMtx.RLock()
numPending := len(f.activeReservations[peerIDKey])
f.resMtx.RUnlock()
channels, err := f.cfg.Wallet.Cfg.Database.FetchOpenChannels(peerPubKey)
if err != nil {
f.failFundingFlow(
fmsg.peer, fmsg.msg.PendingChannelID, err,
)
return
}
for _, c := range channels {
if c.IsPending {
numPending++
}
}
// TODO(roasbeef): modify to only accept a _single_ pending channel per
// block unless white listed
if numPending >= f.cfg.MaxPendingChannels {
f.failFundingFlow(
fmsg.peer, fmsg.msg.PendingChannelID,
lnwire.ErrMaxPendingChannels,
)
return
}
// We'll also reject any requests to create channels until we're fully
// synced to the network as we won't be able to properly validate the
// confirmation of the funding transaction.
isSynced, _, err := f.cfg.Wallet.IsSynced()
if err != nil || !isSynced {
if err != nil {
fndgLog.Errorf("unable to query wallet: %v", err)
}
f.failFundingFlow(
fmsg.peer, fmsg.msg.PendingChannelID,
lnwire.ErrSynchronizingChain,
)
return
}
// We'll reject any request to create a channel that's above the
// current soft-limit for channel size.
if msg.FundingAmount > MaxFundingAmount {
f.failFundingFlow(
fmsg.peer, fmsg.msg.PendingChannelID,
lnwire.ErrChanTooLarge,
)
return
}
// We'll, also ensure that the remote party isn't attempting to propose
// a channel that's below our current min channel size.
if amt < f.cfg.MinChanSize {
f.failFundingFlow(
fmsg.peer, fmsg.msg.PendingChannelID,
lnwallet.ErrChanTooSmall(amt, btcutil.Amount(f.cfg.MinChanSize)),
)
return
}
// If request specifies non-zero push amount and 'rejectpush' is set,
// signal an error.
if f.cfg.RejectPush && msg.PushAmount > 0 {
f.failFundingFlow(
fmsg.peer, fmsg.msg.PendingChannelID,
lnwallet.ErrNonZeroPushAmount(),
)
return
}
// Send the OpenChannel request to the ChannelAcceptor to determine whether
// this node will accept the channel.
chanReq := &chanacceptor.ChannelAcceptRequest{
Node: fmsg.peer.IdentityKey(),
OpenChanMsg: fmsg.msg,
}
if !f.cfg.OpenChannelPredicate.Accept(chanReq) {
f.failFundingFlow(
fmsg.peer, fmsg.msg.PendingChannelID,
fmt.Errorf("open channel request rejected"),
)
return
}
fndgLog.Infof("Recv'd fundingRequest(amt=%v, push=%v, delay=%v, "+
"pendingId=%x) from peer(%x)", amt, msg.PushAmount,
msg.CsvDelay, msg.PendingChannelID,
fmsg.peer.IdentityKey().SerializeCompressed())
// Attempt to initialize a reservation within the wallet. If the wallet
// has insufficient resources to create the channel, then the
// reservation attempt may be rejected. Note that since we're on the
// responding side of a single funder workflow, we don't commit any
// funds to the channel ourselves.
//
// Before we init the channel, we'll also check to see if we've
// negotiated the new tweakless commitment format. This is only the
// case if *both* us and the remote peer are signaling the proper
// feature bit.
commitType := commitmentType(
fmsg.peer.LocalFeatures(), fmsg.peer.RemoteFeatures(),
)
chainHash := chainhash.Hash(msg.ChainHash)
req := &lnwallet.InitFundingReserveMsg{
ChainHash: &chainHash,
PendingChanID: msg.PendingChannelID,
NodeID: fmsg.peer.IdentityKey(),
NodeAddr: fmsg.peer.Address(),
LocalFundingAmt: 0,
RemoteFundingAmt: amt,
CommitFeePerKw: chainfee.SatPerKWeight(msg.FeePerKiloWeight),
FundingFeePerKw: 0,
PushMSat: msg.PushAmount,
Flags: msg.ChannelFlags,
MinConfs: 1,
CommitType: commitType,
}
reservation, err := f.cfg.Wallet.InitChannelReservation(req)
if err != nil {
fndgLog.Errorf("Unable to initialize reservation: %v", err)
f.failFundingFlow(fmsg.peer, msg.PendingChannelID, err)
return
}
// As we're the responder, we get to specify the number of confirmations
// that we require before both of us consider the channel open. We'll
// use our mapping to derive the proper number of confirmations based on
// the amount of the channel, and also if any funds are being pushed to
// us.
numConfsReq := f.cfg.NumRequiredConfs(msg.FundingAmount, msg.PushAmount)
reservation.SetNumConfsRequired(numConfsReq)
// We'll also validate and apply all the constraints the initiating
// party is attempting to dictate for our commitment transaction.
channelConstraints := &channeldb.ChannelConstraints{
DustLimit: msg.DustLimit,
ChanReserve: msg.ChannelReserve,
MaxPendingAmount: msg.MaxValueInFlight,
MinHTLC: msg.HtlcMinimum,
MaxAcceptedHtlcs: msg.MaxAcceptedHTLCs,
CsvDelay: msg.CsvDelay,
}
err = reservation.CommitConstraints(channelConstraints)
if err != nil {
fndgLog.Errorf("Unacceptable channel constraints: %v", err)
f.failFundingFlow(fmsg.peer, fmsg.msg.PendingChannelID, err)
return
}
// Check whether the peer supports upfront shutdown, and get a new wallet
// address if our node is configured to set shutdown addresses by default.
// A nil address is set in place of user input, because this channel open
// was not initiated by the user.
shutdown, err := getUpfrontShutdownScript(
fmsg.peer, nil,
func() (lnwire.DeliveryAddress, error) {
addr, err := f.cfg.Wallet.NewAddress(lnwallet.WitnessPubKey, false)
if err != nil {
return nil, err
}
return txscript.PayToAddrScript(addr)
},
)
if err != nil {
f.failFundingFlow(
fmsg.peer, fmsg.msg.PendingChannelID,
fmt.Errorf("getUpfrontShutdownScript error: %v", err),
)
return
}
reservation.SetOurUpfrontShutdown(shutdown)
fndgLog.Infof("Requiring %v confirmations for pendingChan(%x): "+
"amt=%v, push_amt=%v, committype=%v, upfrontShutdown=%x", numConfsReq,
fmsg.msg.PendingChannelID, amt, msg.PushAmount,
commitType, msg.UpfrontShutdownScript)
// Generate our required constraints for the remote party.
remoteCsvDelay := f.cfg.RequiredRemoteDelay(amt)
chanReserve := f.cfg.RequiredRemoteChanReserve(amt, msg.DustLimit)
maxValue := f.cfg.RequiredRemoteMaxValue(amt)
maxHtlcs := f.cfg.RequiredRemoteMaxHTLCs(amt)
minHtlc := f.cfg.DefaultMinHtlcIn
// Once the reservation has been created successfully, we add it to
// this peer's map of pending reservations to track this particular
// reservation until either abort or completion.
f.resMtx.Lock()
if _, ok := f.activeReservations[peerIDKey]; !ok {
f.activeReservations[peerIDKey] = make(pendingChannels)
}
resCtx := &reservationWithCtx{
reservation: reservation,
chanAmt: amt,
remoteCsvDelay: remoteCsvDelay,
remoteMinHtlc: minHtlc,
err: make(chan error, 1),
peer: fmsg.peer,
}
f.activeReservations[peerIDKey][msg.PendingChannelID] = resCtx
f.resMtx.Unlock()
// Update the timestamp once the fundingOpenMsg has been handled.
defer resCtx.updateTimestamp()
// With our parameters set, we'll now process their contribution so we
// can move the funding workflow ahead.
remoteContribution := &lnwallet.ChannelContribution{
FundingAmount: amt,
FirstCommitmentPoint: msg.FirstCommitmentPoint,
ChannelConfig: &channeldb.ChannelConfig{
ChannelConstraints: channeldb.ChannelConstraints{
DustLimit: msg.DustLimit,
MaxPendingAmount: maxValue,
ChanReserve: chanReserve,
MinHTLC: minHtlc,
MaxAcceptedHtlcs: maxHtlcs,
CsvDelay: remoteCsvDelay,
},
MultiSigKey: keychain.KeyDescriptor{
PubKey: copyPubKey(msg.FundingKey),
},
RevocationBasePoint: keychain.KeyDescriptor{
PubKey: copyPubKey(msg.RevocationPoint),
},
PaymentBasePoint: keychain.KeyDescriptor{
PubKey: copyPubKey(msg.PaymentPoint),
},
DelayBasePoint: keychain.KeyDescriptor{
PubKey: copyPubKey(msg.DelayedPaymentPoint),
},
HtlcBasePoint: keychain.KeyDescriptor{
PubKey: copyPubKey(msg.HtlcPoint),
},
},
UpfrontShutdown: msg.UpfrontShutdownScript,
}
err = reservation.ProcessSingleContribution(remoteContribution)
if err != nil {
fndgLog.Errorf("unable to add contribution reservation: %v", err)
f.failFundingFlow(fmsg.peer, msg.PendingChannelID, err)
return
}
fndgLog.Infof("Sending fundingResp for pending_id(%x)",
msg.PendingChannelID)
fndgLog.Debugf("Remote party accepted commitment constraints: %v",
spew.Sdump(remoteContribution.ChannelConfig.ChannelConstraints))
// With the initiator's contribution recorded, respond with our
// contribution in the next message of the workflow.
ourContribution := reservation.OurContribution()
fundingAccept := lnwire.AcceptChannel{
PendingChannelID: msg.PendingChannelID,
DustLimit: ourContribution.DustLimit,
MaxValueInFlight: maxValue,
ChannelReserve: chanReserve,
MinAcceptDepth: uint32(numConfsReq),
HtlcMinimum: minHtlc,
CsvDelay: remoteCsvDelay,
MaxAcceptedHTLCs: maxHtlcs,
FundingKey: ourContribution.MultiSigKey.PubKey,
RevocationPoint: ourContribution.RevocationBasePoint.PubKey,
PaymentPoint: ourContribution.PaymentBasePoint.PubKey,
DelayedPaymentPoint: ourContribution.DelayBasePoint.PubKey,
HtlcPoint: ourContribution.HtlcBasePoint.PubKey,
FirstCommitmentPoint: ourContribution.FirstCommitmentPoint,
UpfrontShutdownScript: ourContribution.UpfrontShutdown,
}
if err := fmsg.peer.SendMessage(true, &fundingAccept); err != nil {
fndgLog.Errorf("unable to send funding response to peer: %v", err)
f.failFundingFlow(fmsg.peer, msg.PendingChannelID, err)
return
}
}
// processFundingAccept sends a message to the fundingManager allowing it to
// continue the second phase of a funding workflow with the target peer.
func (f *fundingManager) processFundingAccept(msg *lnwire.AcceptChannel,
peer lnpeer.Peer) {
select {
case f.fundingMsgs <- &fundingAcceptMsg{msg, peer}:
case <-f.quit:
return
}
}
// handleFundingAccept processes a response to the workflow initiation sent by
// the remote peer. This message then queues a message with the funding
// outpoint, and a commitment signature to the remote peer.
func (f *fundingManager) handleFundingAccept(fmsg *fundingAcceptMsg) {
msg := fmsg.msg
pendingChanID := fmsg.msg.PendingChannelID
peerKey := fmsg.peer.IdentityKey()
resCtx, err := f.getReservationCtx(peerKey, pendingChanID)
if err != nil {
fndgLog.Warnf("Can't find reservation (peerKey:%v, chan_id:%v)",
peerKey, pendingChanID)
return
}
// Update the timestamp once the fundingAcceptMsg has been handled.
defer resCtx.updateTimestamp()
fndgLog.Infof("Recv'd fundingResponse for pending_id(%x)",
pendingChanID[:])
// The required number of confirmations should not be greater than the
// maximum number of confirmations required by the ChainNotifier to
// properly dispatch confirmations.
if msg.MinAcceptDepth > chainntnfs.MaxNumConfs {
err := lnwallet.ErrNumConfsTooLarge(
msg.MinAcceptDepth, chainntnfs.MaxNumConfs,
)
fndgLog.Warnf("Unacceptable channel constraints: %v", err)
f.failFundingFlow(fmsg.peer, fmsg.msg.PendingChannelID, err)
return
}
// We'll also specify the responder's preference for the number of
// required confirmations, and also the set of channel constraints
// they've specified for commitment states we can create.
resCtx.reservation.SetNumConfsRequired(uint16(msg.MinAcceptDepth))
channelConstraints := &channeldb.ChannelConstraints{
DustLimit: msg.DustLimit,
ChanReserve: msg.ChannelReserve,
MaxPendingAmount: msg.MaxValueInFlight,
MinHTLC: msg.HtlcMinimum,
MaxAcceptedHtlcs: msg.MaxAcceptedHTLCs,
CsvDelay: msg.CsvDelay,
}
err = resCtx.reservation.CommitConstraints(channelConstraints)
if err != nil {
fndgLog.Warnf("Unacceptable channel constraints: %v", err)
f.failFundingFlow(fmsg.peer, fmsg.msg.PendingChannelID, err)
return
}
// As they've accepted our channel constraints, we'll regenerate them
// here so we can properly commit their accepted constraints to the
// reservation.
chanReserve := f.cfg.RequiredRemoteChanReserve(resCtx.chanAmt, msg.DustLimit)
maxValue := f.cfg.RequiredRemoteMaxValue(resCtx.chanAmt)
maxHtlcs := f.cfg.RequiredRemoteMaxHTLCs(resCtx.chanAmt)
// The remote node has responded with their portion of the channel
// contribution. At this point, we can process their contribution which
// allows us to construct and sign both the commitment transaction, and
// the funding transaction.
remoteContribution := &lnwallet.ChannelContribution{
FirstCommitmentPoint: msg.FirstCommitmentPoint,
ChannelConfig: &channeldb.ChannelConfig{
ChannelConstraints: channeldb.ChannelConstraints{
DustLimit: msg.DustLimit,
MaxPendingAmount: maxValue,
ChanReserve: chanReserve,
MinHTLC: resCtx.remoteMinHtlc,
MaxAcceptedHtlcs: maxHtlcs,
CsvDelay: resCtx.remoteCsvDelay,
},
MultiSigKey: keychain.KeyDescriptor{
PubKey: copyPubKey(msg.FundingKey),
},
RevocationBasePoint: keychain.KeyDescriptor{
PubKey: copyPubKey(msg.RevocationPoint),
},
PaymentBasePoint: keychain.KeyDescriptor{
PubKey: copyPubKey(msg.PaymentPoint),
},
DelayBasePoint: keychain.KeyDescriptor{
PubKey: copyPubKey(msg.DelayedPaymentPoint),
},
HtlcBasePoint: keychain.KeyDescriptor{
PubKey: copyPubKey(msg.HtlcPoint),
},
},
UpfrontShutdown: msg.UpfrontShutdownScript,
}
err = resCtx.reservation.ProcessContribution(remoteContribution)
if err != nil {
fndgLog.Errorf("Unable to process contribution from %v: %v",
peerKey, err)
f.failFundingFlow(fmsg.peer, msg.PendingChannelID, err)
return
}
fndgLog.Infof("pendingChan(%x): remote party proposes num_confs=%v, "+
"csv_delay=%v", pendingChanID[:], msg.MinAcceptDepth, msg.CsvDelay)
fndgLog.Debugf("Remote party accepted commitment constraints: %v",
spew.Sdump(remoteContribution.ChannelConfig.ChannelConstraints))
// Now that we have their contribution, we can extract, then send over
// both the funding out point and our signature for their version of
// the commitment transaction to the remote peer.
outPoint := resCtx.reservation.FundingOutpoint()
_, sig := resCtx.reservation.OurSignatures()
// A new channel has almost finished the funding process. In order to
// properly synchronize with the writeHandler goroutine, we add a new
// channel to the barriers map which will be closed once the channel is
// fully open.
f.barrierMtx.Lock()
channelID := lnwire.NewChanIDFromOutPoint(outPoint)
fndgLog.Debugf("Creating chan barrier for ChanID(%v)", channelID)
f.newChanBarriers[channelID] = make(chan struct{})
f.barrierMtx.Unlock()
// The next message that advances the funding flow will reference the
// channel via its permanent channel ID, so we'll set up this mapping
// so we can retrieve the reservation context once we get the
// FundingSigned message.
f.resMtx.Lock()
f.signedReservations[channelID] = pendingChanID
f.resMtx.Unlock()
fndgLog.Infof("Generated ChannelPoint(%v) for pending_id(%x)", outPoint,
pendingChanID[:])
fundingCreated := &lnwire.FundingCreated{
PendingChannelID: pendingChanID,
FundingPoint: *outPoint,
}
fundingCreated.CommitSig, err = lnwire.NewSigFromRawSignature(sig)
if err != nil {
fndgLog.Errorf("Unable to parse signature: %v", err)
f.failFundingFlow(fmsg.peer, msg.PendingChannelID, err)
return
}
if err := fmsg.peer.SendMessage(true, fundingCreated); err != nil {
fndgLog.Errorf("Unable to send funding complete message: %v", err)
f.failFundingFlow(fmsg.peer, msg.PendingChannelID, err)
return
}
}
// processFundingCreated queues a funding complete message coupled with the
// source peer to the fundingManager.
func (f *fundingManager) processFundingCreated(msg *lnwire.FundingCreated,
peer lnpeer.Peer) {
select {
case f.fundingMsgs <- &fundingCreatedMsg{msg, peer}:
case <-f.quit:
return
}
}
// handleFundingCreated progresses the funding workflow when the daemon is on
// the responding side of a single funder workflow. Once this message has been
// processed, a signature is sent to the remote peer allowing it to broadcast
// the funding transaction, progressing the workflow into the final stage.
func (f *fundingManager) handleFundingCreated(fmsg *fundingCreatedMsg) {
peerKey := fmsg.peer.IdentityKey()
pendingChanID := fmsg.msg.PendingChannelID
resCtx, err := f.getReservationCtx(peerKey, pendingChanID)
if err != nil {
fndgLog.Warnf("can't find reservation (peer_id:%v, chan_id:%x)",
peerKey, pendingChanID[:])
return
}
// The channel initiator has responded with the funding outpoint of the
// final funding transaction, as well as a signature for our version of
// the commitment transaction. So at this point, we can validate the
// initiator's commitment transaction, then send our own if it's valid.
// TODO(roasbeef): make case (p vs P) consistent throughout
fundingOut := fmsg.msg.FundingPoint
fndgLog.Infof("completing pending_id(%x) with ChannelPoint(%v)",
pendingChanID[:], fundingOut)
// With all the necessary data available, attempt to advance the
// funding workflow to the next stage. If this succeeds then the
// funding transaction will broadcast after our next message.
// CompleteReservationSingle will also mark the channel as 'IsPending'
// in the database.
commitSig := fmsg.msg.CommitSig.ToSignatureBytes()
completeChan, err := resCtx.reservation.CompleteReservationSingle(
&fundingOut, commitSig)
if err != nil {
// TODO(roasbeef): better error logging: peerID, channelID, etc.
fndgLog.Errorf("unable to complete single reservation: %v", err)
f.failFundingFlow(fmsg.peer, pendingChanID, err)
return
}
// The channel is marked IsPending in the database, and can be removed
// from the set of active reservations.
f.deleteReservationCtx(peerKey, fmsg.msg.PendingChannelID)
// If something goes wrong before the funding transaction is confirmed,
// we use this convenience method to delete the pending OpenChannel
// from the database.
deleteFromDatabase := func() {
localBalance := completeChan.LocalCommitment.LocalBalance.ToSatoshis()
closeInfo := &channeldb.ChannelCloseSummary{
ChanPoint: completeChan.FundingOutpoint,
ChainHash: completeChan.ChainHash,
RemotePub: completeChan.IdentityPub,
CloseType: channeldb.FundingCanceled,
Capacity: completeChan.Capacity,
SettledBalance: localBalance,
RemoteCurrentRevocation: completeChan.RemoteCurrentRevocation,
RemoteNextRevocation: completeChan.RemoteNextRevocation,
LocalChanConfig: completeChan.LocalChanCfg,
}
// Close the channel with us as the initiator because we are
// deciding to exit the funding flow due to an internal error.
if err := completeChan.CloseChannel(
closeInfo, channeldb.ChanStatusLocalCloseInitiator,
); err != nil {
fndgLog.Errorf("Failed closing channel %v: %v",
completeChan.FundingOutpoint, err)
}
}
// A new channel has almost finished the funding process. In order to
// properly synchronize with the writeHandler goroutine, we add a new
// channel to the barriers map which will be closed once the channel is
// fully open.
f.barrierMtx.Lock()
channelID := lnwire.NewChanIDFromOutPoint(&fundingOut)
fndgLog.Debugf("Creating chan barrier for ChanID(%v)", channelID)
f.newChanBarriers[channelID] = make(chan struct{})
f.barrierMtx.Unlock()
fndgLog.Infof("sending FundingSigned for pending_id(%x) over "+
"ChannelPoint(%v)", pendingChanID[:], fundingOut)
// With their signature for our version of the commitment transaction
// verified, we can now send over our signature to the remote peer.
_, sig := resCtx.reservation.OurSignatures()
ourCommitSig, err := lnwire.NewSigFromRawSignature(sig)
if err != nil {
fndgLog.Errorf("unable to parse signature: %v", err)
f.failFundingFlow(fmsg.peer, pendingChanID, err)
deleteFromDatabase()
return
}
fundingSigned := &lnwire.FundingSigned{
ChanID: channelID,
CommitSig: ourCommitSig,
}
if err := fmsg.peer.SendMessage(true, fundingSigned); err != nil {
fndgLog.Errorf("unable to send FundingSigned message: %v", err)
f.failFundingFlow(fmsg.peer, pendingChanID, err)
deleteFromDatabase()
return
}
// Now that we've sent over our final signature for this channel, we'll
// send it to the ChainArbitrator so it can watch for any on-chain
// actions during this final confirmation stage.
if err := f.cfg.WatchNewChannel(completeChan, peerKey); err != nil {
fndgLog.Errorf("Unable to send new ChannelPoint(%v) for "+
"arbitration: %v", fundingOut, err)
}
// Create an entry in the local discovery map so we can ensure that we
// process the channel confirmation fully before we receive a funding
// locked message.
f.localDiscoveryMtx.Lock()
f.localDiscoverySignals[channelID] = make(chan struct{})
f.localDiscoveryMtx.Unlock()
// Inform the ChannelNotifier that the channel has entered
// pending open state.
f.cfg.NotifyPendingOpenChannelEvent(fundingOut, completeChan)
// At this point we have sent our last funding message to the
// initiating peer before the funding transaction will be broadcast.
// With this last message, our job as the responder is now complete.
// We'll wait for the funding transaction to reach the specified number
// of confirmations, then start normal operations.
//
// When we get to this point we have sent the signComplete message to
// the channel funder, and BOLT#2 specifies that we MUST remember the
// channel for reconnection. The channel is already marked
// as pending in the database, so in case of a disconnect or restart,
// we will continue waiting for the confirmation the next time we start
// the funding manager. In case the funding transaction never appears
// on the blockchain, we must forget this channel. We therefore
// completely forget about this channel if we haven't seen the funding
// transaction in 288 blocks (~ 48 hrs), by canceling the reservation
// and canceling the wait for the funding confirmation.
f.wg.Add(1)
go f.advanceFundingState(completeChan, pendingChanID, nil)
}
// processFundingSigned sends a single funding sign complete message along with
// the source peer to the funding manager.
func (f *fundingManager) processFundingSigned(msg *lnwire.FundingSigned,
peer lnpeer.Peer) {
select {
case f.fundingMsgs <- &fundingSignedMsg{msg, peer}:
case <-f.quit:
return
}
}
// handleFundingSigned processes the final message received in a single funder
// workflow. Once this message is processed, the funding transaction is
// broadcast. Once the funding transaction reaches a sufficient number of
// confirmations, a message is sent to the responding peer along with a compact
// encoding of the location of the channel within the blockchain.
func (f *fundingManager) handleFundingSigned(fmsg *fundingSignedMsg) {
// As the funding signed message will reference the reservation by its
// permanent channel ID, we'll need to perform an intermediate look up
// before we can obtain the reservation.
f.resMtx.Lock()
pendingChanID, ok := f.signedReservations[fmsg.msg.ChanID]
delete(f.signedReservations, fmsg.msg.ChanID)
f.resMtx.Unlock()
if !ok {
err := fmt.Errorf("Unable to find signed reservation for "+
"chan_id=%x", fmsg.msg.ChanID)
fndgLog.Warnf(err.Error())
f.failFundingFlow(fmsg.peer, fmsg.msg.ChanID, err)
return
}
peerKey := fmsg.peer.IdentityKey()
resCtx, err := f.getReservationCtx(peerKey, pendingChanID)
if err != nil {
fndgLog.Warnf("Unable to find reservation (peer_id:%v, "+
"chan_id:%x)", peerKey, pendingChanID[:])
// TODO: add ErrChanNotFound?
f.failFundingFlow(fmsg.peer, pendingChanID, err)
return
}
// Create an entry in the local discovery map so we can ensure that we
// process the channel confirmation fully before we receive a funding
// locked message.
fundingPoint := resCtx.reservation.FundingOutpoint()
permChanID := lnwire.NewChanIDFromOutPoint(fundingPoint)
f.localDiscoveryMtx.Lock()
f.localDiscoverySignals[permChanID] = make(chan struct{})
f.localDiscoveryMtx.Unlock()
// The remote peer has responded with a signature for our commitment
// transaction. We'll verify the signature for validity, then commit
// the state to disk as we can now open the channel.
commitSig := fmsg.msg.CommitSig.ToSignatureBytes()
completeChan, err := resCtx.reservation.CompleteReservation(
nil, commitSig,
)
if err != nil {
fndgLog.Errorf("Unable to complete reservation sign "+
"complete: %v", err)
f.failFundingFlow(fmsg.peer, pendingChanID, err)
return
}
// The channel is now marked IsPending in the database, and we can
// delete it from our set of active reservations.
f.deleteReservationCtx(peerKey, pendingChanID)
// Broadcast the finalized funding transaction to the network, but only
// if we actually have the funding transaction.
if completeChan.ChanType.HasFundingTx() {
fundingTx := completeChan.FundingTxn
fndgLog.Infof("Broadcasting funding tx for ChannelPoint(%v): %v",
completeChan.FundingOutpoint, spew.Sdump(fundingTx))
err = f.cfg.PublishTransaction(fundingTx)
if err != nil {
fndgLog.Errorf("Unable to broadcast funding tx for "+
"ChannelPoint(%v): %v",
completeChan.FundingOutpoint, err)
// We failed to broadcast the funding transaction, but
// watch the channel regardless, in case the
// transaction made it to the network. We will retry
// broadcast at startup.
//
// TODO(halseth): retry more often? Handle with CPFP?
// Just delete from the DB?
}
}
// Now that we have a finalized reservation for this funding flow,
// we'll send the to be active channel to the ChainArbitrator so it can
// watch for any on-chain actions before the channel has fully
// confirmed.
if err := f.cfg.WatchNewChannel(completeChan, peerKey); err != nil {
fndgLog.Errorf("Unable to send new ChannelPoint(%v) for "+
"arbitration: %v", fundingPoint, err)
}
fndgLog.Infof("Finalizing pending_id(%x) over ChannelPoint(%v), "+
"waiting for channel open on-chain", pendingChanID[:],
fundingPoint)
// Send an update to the upstream client that the negotiation process
// is over.
//
// TODO(roasbeef): add abstraction over updates to accommodate
// long-polling, or SSE, etc.
upd := &lnrpc.OpenStatusUpdate{
Update: &lnrpc.OpenStatusUpdate_ChanPending{
ChanPending: &lnrpc.PendingUpdate{
Txid: fundingPoint.Hash[:],
OutputIndex: fundingPoint.Index,
},
},
PendingChanId: pendingChanID[:],
}
select {
case resCtx.updates <- upd:
// Inform the ChannelNotifier that the channel has entered
// pending open state.
f.cfg.NotifyPendingOpenChannelEvent(*fundingPoint, completeChan)
case <-f.quit:
return
}
// At this point we have broadcast the funding transaction and done all
// necessary processing.
f.wg.Add(1)
go f.advanceFundingState(completeChan, pendingChanID, resCtx.updates)
}
// confirmedChannel wraps a confirmed funding transaction, as well as the short
// channel ID which identifies that channel into a single struct. We'll use
// this to pass around the final state of a channel after it has been
// confirmed.
type confirmedChannel struct {
// shortChanID expresses where in the block the funding transaction was
// located.
shortChanID lnwire.ShortChannelID
// fundingTx is the funding transaction that created the channel.
fundingTx *wire.MsgTx
}
// waitForFundingWithTimeout is a wrapper around waitForFundingConfirmation and
// waitForTimeout that will return ErrConfirmationTimeout if we are not the
// channel initiator and the maxWaitNumBlocksFundingConf has passed from the
// funding broadcast height. In case of confirmation, the short channel ID of
// the channel and the funding transaction will be returned.
func (f *fundingManager) waitForFundingWithTimeout(
ch *channeldb.OpenChannel) (*confirmedChannel, error) {
confChan := make(chan *confirmedChannel)
timeoutChan := make(chan error, 1)
cancelChan := make(chan struct{})
f.wg.Add(1)
go f.waitForFundingConfirmation(ch, cancelChan, confChan)
// If we are not the initiator, we have no money at stake and will
// timeout waiting for the funding transaction to confirm after a
// while.
if !ch.IsInitiator {
f.wg.Add(1)
go f.waitForTimeout(ch, cancelChan, timeoutChan)
}
defer close(cancelChan)
select {
case err := <-timeoutChan:
if err != nil {
return nil, err
}
return nil, ErrConfirmationTimeout
case <-f.quit:
// The fundingManager is shutting down, and will resume wait on
// startup.
return nil, ErrFundingManagerShuttingDown
case confirmedChannel, ok := <-confChan:
if !ok {
return nil, fmt.Errorf("waiting for funding" +
"confirmation failed")
}
return confirmedChannel, nil
}
}
// makeFundingScript re-creates the funding script for the funding transaction
// of the target channel.
func makeFundingScript(channel *channeldb.OpenChannel) ([]byte, error) {
localKey := channel.LocalChanCfg.MultiSigKey.PubKey.SerializeCompressed()
remoteKey := channel.RemoteChanCfg.MultiSigKey.PubKey.SerializeCompressed()
multiSigScript, err := input.GenMultiSigScript(localKey, remoteKey)
if err != nil {
return nil, err
}
return input.WitnessScriptHash(multiSigScript)
}
// waitForFundingConfirmation handles the final stages of the channel funding
// process once the funding transaction has been broadcast. The primary
// function of waitForFundingConfirmation is to wait for blockchain
// confirmation, and then to notify the other systems that must be notified
// when a channel has become active for lightning transactions.
// The wait can be canceled by closing the cancelChan. In case of success,
// a *lnwire.ShortChannelID will be passed to confChan.
//
// NOTE: This MUST be run as a goroutine.
func (f *fundingManager) waitForFundingConfirmation(
completeChan *channeldb.OpenChannel, cancelChan <-chan struct{},
confChan chan<- *confirmedChannel) {
defer f.wg.Done()
defer close(confChan)
// Register with the ChainNotifier for a notification once the funding
// transaction reaches `numConfs` confirmations.
txid := completeChan.FundingOutpoint.Hash
fundingScript, err := makeFundingScript(completeChan)
if err != nil {
fndgLog.Errorf("unable to create funding script for "+
"ChannelPoint(%v): %v", completeChan.FundingOutpoint,
err)
return
}
numConfs := uint32(completeChan.NumConfsRequired)
confNtfn, err := f.cfg.Notifier.RegisterConfirmationsNtfn(
&txid, fundingScript, numConfs,
completeChan.FundingBroadcastHeight,
)
if err != nil {
fndgLog.Errorf("Unable to register for confirmation of "+
"ChannelPoint(%v): %v", completeChan.FundingOutpoint,
err)
return
}
fndgLog.Infof("Waiting for funding tx (%v) to reach %v confirmations",
txid, numConfs)
var confDetails *chainntnfs.TxConfirmation
var ok bool
// Wait until the specified number of confirmations has been reached,
// we get a cancel signal, or the wallet signals a shutdown.
select {
case confDetails, ok = <-confNtfn.Confirmed:
// fallthrough
case <-cancelChan:
fndgLog.Warnf("canceled waiting for funding confirmation, "+
"stopping funding flow for ChannelPoint(%v)",
completeChan.FundingOutpoint)
return
case <-f.quit:
fndgLog.Warnf("fundingManager shutting down, stopping funding "+
"flow for ChannelPoint(%v)",
completeChan.FundingOutpoint)
return
}
if !ok {
fndgLog.Warnf("ChainNotifier shutting down, cannot complete "+
"funding flow for ChannelPoint(%v)",
completeChan.FundingOutpoint)
return
}
fundingPoint := completeChan.FundingOutpoint
fndgLog.Infof("ChannelPoint(%v) is now active: ChannelID(%v)",
fundingPoint, lnwire.NewChanIDFromOutPoint(&fundingPoint))
// With the block height and the transaction index known, we can
// construct the compact chanID which is used on the network to unique
// identify channels.
shortChanID := lnwire.ShortChannelID{
BlockHeight: confDetails.BlockHeight,
TxIndex: confDetails.TxIndex,
TxPosition: uint16(fundingPoint.Index),
}
select {
case confChan <- &confirmedChannel{
shortChanID: shortChanID,
fundingTx: confDetails.Tx,
}:
case <-f.quit:
return
}
}
// waitForTimeout will close the timeout channel if maxWaitNumBlocksFundingConf
// has passed from the broadcast height of the given channel. In case of error,
// the error is sent on timeoutChan. The wait can be canceled by closing the
// cancelChan.
//
// NOTE: timeoutChan MUST be buffered.
// NOTE: This MUST be run as a goroutine.
func (f *fundingManager) waitForTimeout(completeChan *channeldb.OpenChannel,
cancelChan <-chan struct{}, timeoutChan chan<- error) {
defer f.wg.Done()
epochClient, err := f.cfg.Notifier.RegisterBlockEpochNtfn(nil)
if err != nil {
timeoutChan <- fmt.Errorf("unable to register for epoch "+
"notification: %v", err)
return
}
defer epochClient.Cancel()
// On block maxHeight we will cancel the funding confirmation wait.
maxHeight := completeChan.FundingBroadcastHeight + maxWaitNumBlocksFundingConf
for {
select {
case epoch, ok := <-epochClient.Epochs:
if !ok {
timeoutChan <- fmt.Errorf("epoch client " +
"shutting down")
return
}
// Close the timeout channel and exit if the block is
// aboce the max height.
if uint32(epoch.Height) >= maxHeight {
fndgLog.Warnf("Waited for %v blocks without "+
"seeing funding transaction confirmed,"+
" cancelling.",
maxWaitNumBlocksFundingConf)
// Notify the caller of the timeout.
close(timeoutChan)
return
}
// TODO: If we are the channel initiator implement
// a method for recovering the funds from the funding
// transaction
case <-cancelChan:
return
case <-f.quit:
// The fundingManager is shutting down, will resume
// waiting for the funding transaction on startup.
return
}
}
}
// handleFundingConfirmation marks a channel as open in the database, and set
// the channelOpeningState markedOpen. In addition it will report the now
// decided short channel ID to the switch, and close the local discovery signal
// for this channel.
func (f *fundingManager) handleFundingConfirmation(
completeChan *channeldb.OpenChannel,
confChannel *confirmedChannel) error {
fundingPoint := completeChan.FundingOutpoint
chanID := lnwire.NewChanIDFromOutPoint(&fundingPoint)
// TODO(roasbeef): ideally persistent state update for chan above
// should be abstracted
// Now that that the channel has been fully confirmed, we'll request
// that the wallet fully verify this channel to ensure that it can be
// used.
err := f.cfg.Wallet.ValidateChannel(completeChan, confChannel.fundingTx)
if err != nil {
// TODO(roasbeef): delete chan state?
return fmt.Errorf("unable to validate channel: %v", err)
}
// The funding transaction now being confirmed, we add this channel to
// the fundingManager's internal persistent state machine that we use
// to track the remaining process of the channel opening. This is
// useful to resume the opening process in case of restarts. We set the
// opening state before we mark the channel opened in the database,
// such that we can receover from one of the db writes failing.
err = f.saveChannelOpeningState(
&fundingPoint, markedOpen, &confChannel.shortChanID,
)
if err != nil {
return fmt.Errorf("error setting channel state to markedOpen: %v",
err)
}
// Now that the channel has been fully confirmed and we successfully
// saved the opening state, we'll mark it as open within the database.
err = completeChan.MarkAsOpen(confChannel.shortChanID)
if err != nil {
return fmt.Errorf("error setting channel pending flag to false: "+
"%v", err)
}
// Inform the ChannelNotifier that the channel has transitioned from
// pending open to open.
f.cfg.NotifyOpenChannelEvent(completeChan.FundingOutpoint)
// As there might already be an active link in the switch with an
// outdated short chan ID, we'll instruct the switch to load the updated
// short chan id from disk.
err = f.cfg.ReportShortChanID(fundingPoint)
if err != nil {
fndgLog.Errorf("unable to report short chan id: %v", err)
}
// Close the discoverySignal channel, indicating to a separate
// goroutine that the channel now is marked as open in the database
// and that it is acceptable to process funding locked messages
// from the peer.
f.localDiscoveryMtx.Lock()
if discoverySignal, ok := f.localDiscoverySignals[chanID]; ok {
close(discoverySignal)
}
f.localDiscoveryMtx.Unlock()
return nil
}
// sendFundingLocked creates and sends the fundingLocked message.
// This should be called after the funding transaction has been confirmed,
// and the channelState is 'markedOpen'.
func (f *fundingManager) sendFundingLocked(
completeChan *channeldb.OpenChannel, channel *lnwallet.LightningChannel,
shortChanID *lnwire.ShortChannelID) error {
chanID := lnwire.NewChanIDFromOutPoint(&completeChan.FundingOutpoint)
var peerKey [33]byte
copy(peerKey[:], completeChan.IdentityPub.SerializeCompressed())
// Next, we'll send over the funding locked message which marks that we
// consider the channel open by presenting the remote party with our
// next revocation key. Without the revocation key, the remote party
// will be unable to propose state transitions.
nextRevocation, err := channel.NextRevocationKey()
if err != nil {
return fmt.Errorf("unable to create next revocation: %v", err)
}
fundingLockedMsg := lnwire.NewFundingLocked(chanID, nextRevocation)
// If the peer has disconnected before we reach this point, we will need
// to wait for him to come back online before sending the fundingLocked
// message. This is special for fundingLocked, since failing to send any
// of the previous messages in the funding flow just cancels the flow.
// But now the funding transaction is confirmed, the channel is open
// and we have to make sure the peer gets the fundingLocked message when
// it comes back online. This is also crucial during restart of lnd,
// where we might try to resend the fundingLocked message before the
// server has had the time to connect to the peer. We keep trying to
// send fundingLocked until we succeed, or the fundingManager is shut
// down.
for {
connected := make(chan lnpeer.Peer, 1)
f.cfg.NotifyWhenOnline(peerKey, connected)
var peer lnpeer.Peer
select {
case peer = <-connected:
case <-f.quit:
return ErrFundingManagerShuttingDown
}
fndgLog.Infof("Peer(%x) is online, sending FundingLocked "+
"for ChannelID(%v)", peerKey, chanID)
if err := peer.SendMessage(true, fundingLockedMsg); err == nil {
// Sending succeeded, we can break out and continue the
// funding flow.
break
}
fndgLog.Warnf("Unable to send fundingLocked to peer %x: %v. "+
"Will retry when online", peerKey, err)
}
return nil
}
// addToRouterGraph sends a ChannelAnnouncement and a ChannelUpdate to the
// gossiper so that the channel is added to the Router's internal graph.
// These announcement messages are NOT broadcasted to the greater network,
// only to the channel counter party. The proofs required to announce the
// channel to the greater network will be created and sent in annAfterSixConfs.
func (f *fundingManager) addToRouterGraph(completeChan *channeldb.OpenChannel,
shortChanID *lnwire.ShortChannelID) error {
chanID := lnwire.NewChanIDFromOutPoint(&completeChan.FundingOutpoint)
// We'll obtain the min HTLC value we can forward in our direction, as
// we'll use this value within our ChannelUpdate. This constraint is
// originally set by the remote node, as it will be the one that will
// need to determine the smallest HTLC it deems economically relevant.
fwdMinHTLC := completeChan.LocalChanCfg.MinHTLC
// We don't necessarily want to go as low as the remote party
// allows. Check it against our default forwarding policy.
if fwdMinHTLC < f.cfg.DefaultRoutingPolicy.MinHTLCOut {
fwdMinHTLC = f.cfg.DefaultRoutingPolicy.MinHTLCOut
}
// We'll obtain the max HTLC value we can forward in our direction, as
// we'll use this value within our ChannelUpdate. This value must be <=
// channel capacity and <= the maximum in-flight msats set by the peer.
fwdMaxHTLC := completeChan.LocalChanCfg.MaxPendingAmount
capacityMSat := lnwire.NewMSatFromSatoshis(completeChan.Capacity)
if fwdMaxHTLC > capacityMSat {
fwdMaxHTLC = capacityMSat
}
ann, err := f.newChanAnnouncement(
f.cfg.IDKey, completeChan.IdentityPub,
completeChan.LocalChanCfg.MultiSigKey.PubKey,
completeChan.RemoteChanCfg.MultiSigKey.PubKey, *shortChanID,
chanID, fwdMinHTLC, fwdMaxHTLC,
)
if err != nil {
return fmt.Errorf("error generating channel "+
"announcement: %v", err)
}
// Send ChannelAnnouncement and ChannelUpdate to the gossiper to add
// to the Router's topology.
errChan := f.cfg.SendAnnouncement(
ann.chanAnn, discovery.ChannelCapacity(completeChan.Capacity),
discovery.ChannelPoint(completeChan.FundingOutpoint),
)
select {
case err := <-errChan:
if err != nil {
if routing.IsError(err, routing.ErrOutdated,
routing.ErrIgnored) {
fndgLog.Debugf("Router rejected "+
"ChannelAnnouncement: %v", err)
} else {
return fmt.Errorf("error sending channel "+
"announcement: %v", err)
}
}
case <-f.quit:
return ErrFundingManagerShuttingDown
}
errChan = f.cfg.SendAnnouncement(ann.chanUpdateAnn)
select {
case err := <-errChan:
if err != nil {
if routing.IsError(err, routing.ErrOutdated,
routing.ErrIgnored) {
fndgLog.Debugf("Router rejected "+
"ChannelUpdate: %v", err)
} else {
return fmt.Errorf("error sending channel "+
"update: %v", err)
}
}
case <-f.quit:
return ErrFundingManagerShuttingDown
}
return nil
}
// annAfterSixConfs broadcasts the necessary channel announcement messages to
// the network after 6 confs. Should be called after the fundingLocked message
// is sent and the channel is added to the router graph (channelState is
// 'addedToRouterGraph') and the channel is ready to be used. This is the last
// step in the channel opening process, and the opening state will be deleted
// from the database if successful.
func (f *fundingManager) annAfterSixConfs(completeChan *channeldb.OpenChannel,
shortChanID *lnwire.ShortChannelID) error {
// If this channel is not meant to be announced to the greater network,
// we'll only send our NodeAnnouncement to our counterparty to ensure we
// don't leak any of our information.
announceChan := completeChan.ChannelFlags&lnwire.FFAnnounceChannel != 0
if !announceChan {
fndgLog.Debugf("Will not announce private channel %v.",
shortChanID.ToUint64())
peerChan := make(chan lnpeer.Peer, 1)
var peerKey [33]byte
copy(peerKey[:], completeChan.IdentityPub.SerializeCompressed())
f.cfg.NotifyWhenOnline(peerKey, peerChan)
var peer lnpeer.Peer
select {
case peer = <-peerChan:
case <-f.quit:
return ErrFundingManagerShuttingDown
}
nodeAnn, err := f.cfg.CurrentNodeAnnouncement()
if err != nil {
return fmt.Errorf("unable to retrieve current node "+
"announcement: %v", err)
}
chanID := lnwire.NewChanIDFromOutPoint(
&completeChan.FundingOutpoint,
)
pubKey := peer.PubKey()
fndgLog.Debugf("Sending our NodeAnnouncement for "+
"ChannelID(%v) to %x", chanID, pubKey)
// TODO(halseth): make reliable. If the peer is not online this
// will fail, and the opening process will stop. Should instead
// block here, waiting for the peer to come online.
if err := peer.SendMessage(true, &nodeAnn); err != nil {
return fmt.Errorf("unable to send node announcement "+
"to peer %x: %v", pubKey, err)
}
} else {
// Otherwise, we'll wait until the funding transaction has
// reached 6 confirmations before announcing it.
numConfs := uint32(completeChan.NumConfsRequired)
if numConfs < 6 {
numConfs = 6
}
txid := completeChan.FundingOutpoint.Hash
fndgLog.Debugf("Will announce channel %v after ChannelPoint"+
"(%v) has gotten %d confirmations",
shortChanID.ToUint64(), completeChan.FundingOutpoint,
numConfs)
fundingScript, err := makeFundingScript(completeChan)
if err != nil {
return fmt.Errorf("unable to create funding script for "+
"ChannelPoint(%v): %v",
completeChan.FundingOutpoint, err)
}
// Register with the ChainNotifier for a notification once the
// funding transaction reaches at least 6 confirmations.
confNtfn, err := f.cfg.Notifier.RegisterConfirmationsNtfn(
&txid, fundingScript, numConfs,
completeChan.FundingBroadcastHeight,
)
if err != nil {
return fmt.Errorf("Unable to register for "+
"confirmation of ChannelPoint(%v): %v",
completeChan.FundingOutpoint, err)
}
// Wait until 6 confirmations has been reached or the wallet
// signals a shutdown.
select {
case _, ok := <-confNtfn.Confirmed:
if !ok {
return fmt.Errorf("ChainNotifier shutting "+
"down, cannot complete funding flow "+
"for ChannelPoint(%v)",
completeChan.FundingOutpoint)
}
// Fallthrough.
case <-f.quit:
return fmt.Errorf("%v, stopping funding flow for "+
"ChannelPoint(%v)",
ErrFundingManagerShuttingDown,
completeChan.FundingOutpoint)
}
fundingPoint := completeChan.FundingOutpoint
chanID := lnwire.NewChanIDFromOutPoint(&fundingPoint)
fndgLog.Infof("Announcing ChannelPoint(%v), short_chan_id=%v",
&fundingPoint, shortChanID)
// Create and broadcast the proofs required to make this channel
// public and usable for other nodes for routing.
err = f.announceChannel(
f.cfg.IDKey, completeChan.IdentityPub,
completeChan.LocalChanCfg.MultiSigKey.PubKey,
completeChan.RemoteChanCfg.MultiSigKey.PubKey,
*shortChanID, chanID,
)
if err != nil {
return fmt.Errorf("channel announcement failed: %v", err)
}
fndgLog.Debugf("Channel with ChannelPoint(%v), short_chan_id=%v "+
"announced", &fundingPoint, shortChanID)
}
return nil
}
// processFundingLocked sends a message to the fundingManager allowing it to
// finish the funding workflow.
func (f *fundingManager) processFundingLocked(msg *lnwire.FundingLocked,
peer lnpeer.Peer) {
select {
case f.fundingMsgs <- &fundingLockedMsg{msg, peer}:
case <-f.quit:
return
}
}
// handleFundingLocked finalizes the channel funding process and enables the
// channel to enter normal operating mode.
func (f *fundingManager) handleFundingLocked(fmsg *fundingLockedMsg) {
defer f.wg.Done()
fndgLog.Debugf("Received FundingLocked for ChannelID(%v) from "+
"peer %x", fmsg.msg.ChanID,
fmsg.peer.IdentityKey().SerializeCompressed())
// If we are currently in the process of handling a funding locked
// message for this channel, ignore.
f.handleFundingLockedMtx.Lock()
_, ok := f.handleFundingLockedBarriers[fmsg.msg.ChanID]
if ok {
fndgLog.Infof("Already handling fundingLocked for "+
"ChannelID(%v), ignoring.", fmsg.msg.ChanID)
f.handleFundingLockedMtx.Unlock()
return
}
// If not already handling fundingLocked for this channel, set up
// barrier, and move on.
f.handleFundingLockedBarriers[fmsg.msg.ChanID] = struct{}{}
f.handleFundingLockedMtx.Unlock()
defer func() {
f.handleFundingLockedMtx.Lock()
delete(f.handleFundingLockedBarriers, fmsg.msg.ChanID)
f.handleFundingLockedMtx.Unlock()
}()
f.localDiscoveryMtx.Lock()
localDiscoverySignal, ok := f.localDiscoverySignals[fmsg.msg.ChanID]
f.localDiscoveryMtx.Unlock()
if ok {
// Before we proceed with processing the funding locked
// message, we'll wait for the local waitForFundingConfirmation
// goroutine to signal that it has the necessary state in
// place. Otherwise, we may be missing critical information
// required to handle forwarded HTLC's.
select {
case <-localDiscoverySignal:
// Fallthrough
case <-f.quit:
return
}
// With the signal received, we can now safely delete the entry
// from the map.
f.localDiscoveryMtx.Lock()
delete(f.localDiscoverySignals, fmsg.msg.ChanID)
f.localDiscoveryMtx.Unlock()
}
// First, we'll attempt to locate the channel whose funding workflow is
// being finalized by this message. We go to the database rather than
// our reservation map as we may have restarted, mid funding flow.
chanID := fmsg.msg.ChanID
channel, err := f.cfg.FindChannel(chanID)
if err != nil {
fndgLog.Errorf("Unable to locate ChannelID(%v), cannot complete "+
"funding", chanID)
return
}
// If the RemoteNextRevocation is non-nil, it means that we have
// already processed fundingLocked for this channel, so ignore.
if channel.RemoteNextRevocation != nil {
fndgLog.Infof("Received duplicate fundingLocked for "+
"ChannelID(%v), ignoring.", chanID)
return
}
// The funding locked message contains the next commitment point we'll
// need to create the next commitment state for the remote party. So
// we'll insert that into the channel now before passing it along to
// other sub-systems.
err = channel.InsertNextRevocation(fmsg.msg.NextPerCommitmentPoint)
if err != nil {
fndgLog.Errorf("unable to insert next commitment point: %v", err)
return
}
// Launch a defer so we _ensure_ that the channel barrier is properly
// closed even if the target peer is no longer online at this point.
defer func() {
// Close the active channel barrier signaling the readHandler
// that commitment related modifications to this channel can
// now proceed.
f.barrierMtx.Lock()
chanBarrier, ok := f.newChanBarriers[chanID]
if ok {
fndgLog.Tracef("Closing chan barrier for ChanID(%v)",
chanID)
close(chanBarrier)
delete(f.newChanBarriers, chanID)
}
f.barrierMtx.Unlock()
}()
if err := fmsg.peer.AddNewChannel(channel, f.quit); err != nil {
fndgLog.Errorf("Unable to add new channel %v with peer %x: %v",
fmsg.peer.IdentityKey().SerializeCompressed(),
channel.FundingOutpoint, err)
}
}
// chanAnnouncement encapsulates the two authenticated announcements that we
// send out to the network after a new channel has been created locally.
type chanAnnouncement struct {
chanAnn *lnwire.ChannelAnnouncement
chanUpdateAnn *lnwire.ChannelUpdate
chanProof *lnwire.AnnounceSignatures
}
// newChanAnnouncement creates the authenticated channel announcement messages
// required to broadcast a newly created channel to the network. The
// announcement is two part: the first part authenticates the existence of the
// channel and contains four signatures binding the funding pub keys and
// identity pub keys of both parties to the channel, and the second segment is
// authenticated only by us and contains our directional routing policy for the
// channel.
func (f *fundingManager) newChanAnnouncement(localPubKey, remotePubKey,
localFundingKey, remoteFundingKey *btcec.PublicKey,
shortChanID lnwire.ShortChannelID, chanID lnwire.ChannelID,
fwdMinHTLC, fwdMaxHTLC lnwire.MilliSatoshi) (*chanAnnouncement, error) {
chainHash := *f.cfg.Wallet.Cfg.NetParams.GenesisHash
// The unconditional section of the announcement is the ShortChannelID
// itself which compactly encodes the location of the funding output
// within the blockchain.
chanAnn := &lnwire.ChannelAnnouncement{
ShortChannelID: shortChanID,
Features: lnwire.NewRawFeatureVector(),
ChainHash: chainHash,
}
// The chanFlags field indicates which directed edge of the channel is
// being updated within the ChannelUpdateAnnouncement announcement
// below. A value of zero means it's the edge of the "first" node and 1
// being the other node.
var chanFlags lnwire.ChanUpdateChanFlags
// The lexicographical ordering of the two identity public keys of the
// nodes indicates which of the nodes is "first". If our serialized
// identity key is lower than theirs then we're the "first" node and
// second otherwise.
selfBytes := localPubKey.SerializeCompressed()
remoteBytes := remotePubKey.SerializeCompressed()
if bytes.Compare(selfBytes, remoteBytes) == -1 {
copy(chanAnn.NodeID1[:], localPubKey.SerializeCompressed())
copy(chanAnn.NodeID2[:], remotePubKey.SerializeCompressed())
copy(chanAnn.BitcoinKey1[:], localFundingKey.SerializeCompressed())
copy(chanAnn.BitcoinKey2[:], remoteFundingKey.SerializeCompressed())
// If we're the first node then update the chanFlags to
// indicate the "direction" of the update.
chanFlags = 0
} else {
copy(chanAnn.NodeID1[:], remotePubKey.SerializeCompressed())
copy(chanAnn.NodeID2[:], localPubKey.SerializeCompressed())
copy(chanAnn.BitcoinKey1[:], remoteFundingKey.SerializeCompressed())
copy(chanAnn.BitcoinKey2[:], localFundingKey.SerializeCompressed())
// If we're the second node then update the chanFlags to
// indicate the "direction" of the update.
chanFlags = 1
}
// Our channel update message flags will signal that we support the
// max_htlc field.
msgFlags := lnwire.ChanUpdateOptionMaxHtlc
// We announce the channel with the default values. Some of
// these values can later be changed by crafting a new ChannelUpdate.
chanUpdateAnn := &lnwire.ChannelUpdate{
ShortChannelID: shortChanID,
ChainHash: chainHash,
Timestamp: uint32(time.Now().Unix()),
MessageFlags: msgFlags,
ChannelFlags: chanFlags,
TimeLockDelta: uint16(f.cfg.DefaultRoutingPolicy.TimeLockDelta),
// We use the HtlcMinimumMsat that the remote party required us
// to use, as our ChannelUpdate will be used to carry HTLCs
// towards them.
HtlcMinimumMsat: fwdMinHTLC,
HtlcMaximumMsat: fwdMaxHTLC,
BaseFee: uint32(f.cfg.DefaultRoutingPolicy.BaseFee),
FeeRate: uint32(f.cfg.DefaultRoutingPolicy.FeeRate),
}
// With the channel update announcement constructed, we'll generate a
// signature that signs a double-sha digest of the announcement.
// This'll serve to authenticate this announcement and any other future
// updates we may send.
chanUpdateMsg, err := chanUpdateAnn.DataToSign()
if err != nil {
return nil, err
}
sig, err := f.cfg.SignMessage(f.cfg.IDKey, chanUpdateMsg)
if err != nil {
return nil, errors.Errorf("unable to generate channel "+
"update announcement signature: %v", err)
}
chanUpdateAnn.Signature, err = lnwire.NewSigFromSignature(sig)
if err != nil {
return nil, errors.Errorf("unable to generate channel "+
"update announcement signature: %v", err)
}
// The channel existence proofs itself is currently announced in
// distinct message. In order to properly authenticate this message, we
// need two signatures: one under the identity public key used which
// signs the message itself and another signature of the identity
// public key under the funding key itself.
//
// TODO(roasbeef): use SignAnnouncement here instead?
chanAnnMsg, err := chanAnn.DataToSign()
if err != nil {
return nil, err
}
nodeSig, err := f.cfg.SignMessage(f.cfg.IDKey, chanAnnMsg)
if err != nil {
return nil, errors.Errorf("unable to generate node "+
"signature for channel announcement: %v", err)
}
bitcoinSig, err := f.cfg.SignMessage(localFundingKey, chanAnnMsg)
if err != nil {
return nil, errors.Errorf("unable to generate bitcoin "+
"signature for node public key: %v", err)
}
// Finally, we'll generate the announcement proof which we'll use to
// provide the other side with the necessary signatures required to
// allow them to reconstruct the full channel announcement.
proof := &lnwire.AnnounceSignatures{
ChannelID: chanID,
ShortChannelID: shortChanID,
}
proof.NodeSignature, err = lnwire.NewSigFromSignature(nodeSig)
if err != nil {
return nil, err
}
proof.BitcoinSignature, err = lnwire.NewSigFromSignature(bitcoinSig)
if err != nil {
return nil, err
}
return &chanAnnouncement{
chanAnn: chanAnn,
chanUpdateAnn: chanUpdateAnn,
chanProof: proof,
}, nil
}
// announceChannel announces a newly created channel to the rest of the network
// by crafting the two authenticated announcements required for the peers on
// the network to recognize the legitimacy of the channel. The crafted
// announcements are then sent to the channel router to handle broadcasting to
// the network during its next trickle.
// This method is synchronous and will return when all the network requests
// finish, either successfully or with an error.
func (f *fundingManager) announceChannel(localIDKey, remoteIDKey, localFundingKey,
remoteFundingKey *btcec.PublicKey, shortChanID lnwire.ShortChannelID,
chanID lnwire.ChannelID) error {
// First, we'll create the batch of announcements to be sent upon
// initial channel creation. This includes the channel announcement
// itself, the channel update announcement, and our half of the channel
// proof needed to fully authenticate the channel.
//
// We can pass in zeroes for the min and max htlc policy, because we
// only use the channel announcement message from the returned struct.
ann, err := f.newChanAnnouncement(localIDKey, remoteIDKey,
localFundingKey, remoteFundingKey, shortChanID, chanID,
0, 0,
)
if err != nil {
fndgLog.Errorf("can't generate channel announcement: %v", err)
return err
}
// We only send the channel proof announcement and the node announcement
// because addToRouterGraph previously sent the ChannelAnnouncement and
// the ChannelUpdate announcement messages. The channel proof and node
// announcements are broadcast to the greater network.
errChan := f.cfg.SendAnnouncement(ann.chanProof)
select {
case err := <-errChan:
if err != nil {
if routing.IsError(err, routing.ErrOutdated,
routing.ErrIgnored) {
fndgLog.Debugf("Router rejected "+
"AnnounceSignatures: %v", err)
} else {
fndgLog.Errorf("Unable to send channel "+
"proof: %v", err)
return err
}
}
case <-f.quit:
return ErrFundingManagerShuttingDown
}
// Now that the channel is announced to the network, we will also
// obtain and send a node announcement. This is done since a node
// announcement is only accepted after a channel is known for that
// particular node, and this might be our first channel.
nodeAnn, err := f.cfg.CurrentNodeAnnouncement()
if err != nil {
fndgLog.Errorf("can't generate node announcement: %v", err)
return err
}
errChan = f.cfg.SendAnnouncement(&nodeAnn)
select {
case err := <-errChan:
if err != nil {
if routing.IsError(err, routing.ErrOutdated,
routing.ErrIgnored) {
fndgLog.Debugf("Router rejected "+
"NodeAnnouncement: %v", err)
} else {
fndgLog.Errorf("Unable to send node "+
"announcement: %v", err)
return err
}
}
case <-f.quit:
return ErrFundingManagerShuttingDown
}
return nil
}
// initFundingWorkflow sends a message to the funding manager instructing it
// to initiate a single funder workflow with the source peer.
// TODO(roasbeef): re-visit blocking nature..
func (f *fundingManager) initFundingWorkflow(peer lnpeer.Peer, req *openChanReq) {
f.fundingRequests <- &initFundingMsg{
peer: peer,
openChanReq: req,
}
}
// getUpfrontShutdownScript takes a user provided script and a getScript
// function which can be used to generate an upfront shutdown script. If our
// peer does not support the feature, this function will error if a non-zero
// script was provided by the user, and return an empty script otherwise. If
// our peer does support the feature, we will return the user provided script
// if non-zero, or a freshly generated script if our node is configured to set
// upfront shutdown scripts automatically.
func getUpfrontShutdownScript(peer lnpeer.Peer, script lnwire.DeliveryAddress,
getScript func() (lnwire.DeliveryAddress, error)) (lnwire.DeliveryAddress,
error) {
// Check whether the remote peer supports upfront shutdown scripts.
remoteUpfrontShutdown := peer.RemoteFeatures().HasFeature(
lnwire.UpfrontShutdownScriptOptional,
)
// If the peer does not support upfront shutdown scripts, and one has been
// provided, return an error because the feature is not supported.
if !remoteUpfrontShutdown && len(script) != 0 {
return nil, errUpfrontShutdownScriptNotSupported
}
// If the peer does not support upfront shutdown, return an empty address.
if !remoteUpfrontShutdown {
return nil, nil
}
// If the user has provided an script and the peer supports the feature,
// return it. Note that user set scripts override the enable upfront
// shutdown flag.
if len(script) > 0 {
return script, nil
}
// If we do not have setting of upfront shutdown script enabled, return
// an empty script.
if !cfg.EnableUpfrontShutdown {
return nil, nil
}
return getScript()
}
// handleInitFundingMsg creates a channel reservation within the daemon's
// wallet, then sends a funding request to the remote peer kicking off the
// funding workflow.
func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) {
var (
peerKey = msg.peer.IdentityKey()
localAmt = msg.localFundingAmt
minHtlcIn = msg.minHtlcIn
remoteCsvDelay = msg.remoteCsvDelay
)
// We'll determine our dust limit depending on which chain is active.
var ourDustLimit btcutil.Amount
switch registeredChains.PrimaryChain() {
case bitcoinChain:
ourDustLimit = lnwallet.DefaultDustLimit()
case litecoinChain:
ourDustLimit = defaultLitecoinDustLimit
}
fndgLog.Infof("Initiating fundingRequest(local_amt=%v "+
"(subtract_fees=%v), push_amt=%v, chain_hash=%v, peer=%x, "+
"dust_limit=%v, min_confs=%v)", localAmt, msg.subtractFees,
msg.pushAmt, msg.chainHash, peerKey.SerializeCompressed(),
ourDustLimit, msg.minConfs)
// First, we'll query the fee estimator for a fee that should get the
// commitment transaction confirmed by the next few blocks (conf target
// of 3). We target the near blocks here to ensure that we'll be able
// to execute a timely unilateral channel closure if needed.
commitFeePerKw, err := f.cfg.FeeEstimator.EstimateFeePerKW(3)
if err != nil {
msg.err <- err
return
}
// We set the channel flags to indicate whether we want this channel to
// be announced to the network.
var channelFlags lnwire.FundingFlag
if !msg.openChanReq.private {
// This channel will be announced.
channelFlags = lnwire.FFAnnounceChannel
}
// If the caller specified their own channel ID, then we'll use that.
// Otherwise we'll generate a fresh one as normal. This will be used
// to track this reservation throughout its lifetime.
var chanID [32]byte
if msg.pendingChanID == zeroID {
chanID = f.nextPendingChanID()
} else {
// If the user specified their own pending channel ID, then
// we'll ensure it doesn't collide with any existing pending
// channel ID.
chanID = msg.pendingChanID
if _, err := f.getReservationCtx(peerKey, chanID); err == nil {
msg.err <- fmt.Errorf("pendingChannelID(%x) "+
"already present", chanID[:])
return
}
}
// Initialize a funding reservation with the local wallet. If the
// wallet doesn't have enough funds to commit to this channel, then the
// request will fail, and be aborted.
//
// Before we init the channel, we'll also check to see if we've
// negotiated the new tweakless commitment format. This is only the
// case if *both* us and the remote peer are signaling the proper
// feature bit.
commitType := commitmentType(
msg.peer.LocalFeatures(), msg.peer.RemoteFeatures(),
)
req := &lnwallet.InitFundingReserveMsg{
ChainHash: &msg.chainHash,
PendingChanID: chanID,
NodeID: peerKey,
NodeAddr: msg.peer.Address(),
SubtractFees: msg.subtractFees,
LocalFundingAmt: localAmt,
RemoteFundingAmt: 0,
CommitFeePerKw: commitFeePerKw,
FundingFeePerKw: msg.fundingFeePerKw,
PushMSat: msg.pushAmt,
Flags: channelFlags,
MinConfs: msg.minConfs,
CommitType: commitType,
ChanFunder: msg.chanFunder,
}
reservation, err := f.cfg.Wallet.InitChannelReservation(req)
if err != nil {
msg.err <- err
return
}
// Check whether the peer supports upfront shutdown, and get an address which
// should be used (either a user specified address or a new address from the
// wallet if our node is configured to set shutdown address by default).
shutdown, err := getUpfrontShutdownScript(
msg.peer, msg.openChanReq.shutdownScript,
func() (lnwire.DeliveryAddress, error) {
addr, err := f.cfg.Wallet.NewAddress(lnwallet.WitnessPubKey, false)
if err != nil {
return nil, err
}
return txscript.PayToAddrScript(addr)
},
)
if err != nil {
msg.err <- err
return
}
// Set our upfront shutdown address in the existing reservation.
reservation.SetOurUpfrontShutdown(shutdown)
// Now that we have successfully reserved funds for this channel in the
// wallet, we can fetch the final channel capacity. This is done at
// this point since the final capacity might change in case of
// SubtractFees=true.
capacity := reservation.Capacity()
fndgLog.Infof("Target commit tx sat/kw for pendingID(%x): %v", chanID,
int64(commitFeePerKw))
// If the remote CSV delay was not set in the open channel request,
// we'll use the RequiredRemoteDelay closure to compute the delay we
// require given the total amount of funds within the channel.
if remoteCsvDelay == 0 {
remoteCsvDelay = f.cfg.RequiredRemoteDelay(capacity)
}
// If no minimum HTLC value was specified, use the default one.
if minHtlcIn == 0 {
minHtlcIn = f.cfg.DefaultMinHtlcIn
}
// If a pending channel map for this peer isn't already created, then
// we create one, ultimately allowing us to track this pending
// reservation within the target peer.
peerIDKey := newSerializedKey(peerKey)
f.resMtx.Lock()
if _, ok := f.activeReservations[peerIDKey]; !ok {
f.activeReservations[peerIDKey] = make(pendingChannels)
}
resCtx := &reservationWithCtx{
chanAmt: capacity,
remoteCsvDelay: remoteCsvDelay,
remoteMinHtlc: minHtlcIn,
reservation: reservation,
peer: msg.peer,
updates: msg.updates,
err: msg.err,
}
f.activeReservations[peerIDKey][chanID] = resCtx
f.resMtx.Unlock()
// Update the timestamp once the initFundingMsg has been handled.
defer resCtx.updateTimestamp()
// Once the reservation has been created, and indexed, queue a funding
// request to the remote peer, kicking off the funding workflow.
ourContribution := reservation.OurContribution()
// Finally, we'll use the current value of the channels and our default
// policy to determine of required commitment constraints for the
// remote party.
chanReserve := f.cfg.RequiredRemoteChanReserve(capacity, ourDustLimit)
maxValue := f.cfg.RequiredRemoteMaxValue(capacity)
maxHtlcs := f.cfg.RequiredRemoteMaxHTLCs(capacity)
fndgLog.Infof("Starting funding workflow with %v for pending_id(%x), "+
"committype=%v", msg.peer.Address(), chanID, commitType)
fundingOpen := lnwire.OpenChannel{
ChainHash: *f.cfg.Wallet.Cfg.NetParams.GenesisHash,
PendingChannelID: chanID,
FundingAmount: capacity,
PushAmount: msg.pushAmt,
DustLimit: ourContribution.DustLimit,
MaxValueInFlight: maxValue,
ChannelReserve: chanReserve,
HtlcMinimum: minHtlcIn,
FeePerKiloWeight: uint32(commitFeePerKw),
CsvDelay: remoteCsvDelay,
MaxAcceptedHTLCs: maxHtlcs,
FundingKey: ourContribution.MultiSigKey.PubKey,
RevocationPoint: ourContribution.RevocationBasePoint.PubKey,
PaymentPoint: ourContribution.PaymentBasePoint.PubKey,
HtlcPoint: ourContribution.HtlcBasePoint.PubKey,
DelayedPaymentPoint: ourContribution.DelayBasePoint.PubKey,
FirstCommitmentPoint: ourContribution.FirstCommitmentPoint,
ChannelFlags: channelFlags,
UpfrontShutdownScript: shutdown,
}
if err := msg.peer.SendMessage(true, &fundingOpen); err != nil {
e := fmt.Errorf("Unable to send funding request message: %v",
err)
fndgLog.Errorf(e.Error())
// Since we were unable to send the initial message to the peer
// and start the funding flow, we'll cancel this reservation.
if _, err := f.cancelReservationCtx(peerKey, chanID); err != nil {
fndgLog.Errorf("unable to cancel reservation: %v", err)
}
msg.err <- e
return
}
}
// waitUntilChannelOpen is designed to prevent other lnd subsystems from
// sending new update messages to a channel before the channel is fully
// opened.
func (f *fundingManager) waitUntilChannelOpen(targetChan lnwire.ChannelID,
quit <-chan struct{}) error {
f.barrierMtx.RLock()
barrier, ok := f.newChanBarriers[targetChan]
f.barrierMtx.RUnlock()
if ok {
fndgLog.Tracef("waiting for chan barrier signal for ChanID(%v)",
targetChan)
select {
case <-barrier:
case <-quit:
return ErrFundingManagerShuttingDown
case <-f.quit:
return ErrFundingManagerShuttingDown
}
fndgLog.Tracef("barrier for ChanID(%v) closed", targetChan)
return nil
}
return nil
}
// processFundingError sends a message to the fundingManager allowing it to
// process the occurred generic error.
func (f *fundingManager) processFundingError(err *lnwire.Error,
peerKey *btcec.PublicKey) {
select {
case f.fundingMsgs <- &fundingErrorMsg{err, peerKey}:
case <-f.quit:
return
}
}
// handleErrorMsg processes the error which was received from remote peer,
// depending on the type of error we should do different clean up steps and
// inform the user about it.
func (f *fundingManager) handleErrorMsg(fmsg *fundingErrorMsg) {
protocolErr := fmsg.err
chanID := fmsg.err.ChanID
// First, we'll attempt to retrieve and cancel the funding workflow
// that this error was tied to. If we're unable to do so, then we'll
// exit early as this was an unwarranted error.
resCtx, err := f.cancelReservationCtx(fmsg.peerKey, chanID)
if err != nil {
fndgLog.Warnf("Received error for non-existent funding "+
"flow: %v (%v)", err, protocolErr.Error())
return
}
// If we did indeed find the funding workflow, then we'll return the
// error back to the caller (if any), and cancel the workflow itself.
fundingErr := fmt.Errorf("received funding error from %x: %v",
fmsg.peerKey.SerializeCompressed(), protocolErr.Error(),
)
fndgLog.Errorf(fundingErr.Error())
resCtx.err <- fundingErr
}
// pruneZombieReservations loops through all pending reservations and fails the
// funding flow for any reservations that have not been updated since the
// ReservationTimeout and are not locked waiting for the funding transaction.
func (f *fundingManager) pruneZombieReservations() {
zombieReservations := make(pendingChannels)
f.resMtx.RLock()
for _, pendingReservations := range f.activeReservations {
for pendingChanID, resCtx := range pendingReservations {
if resCtx.isLocked() {
continue
}
if time.Since(resCtx.lastUpdated) > f.cfg.ReservationTimeout {
zombieReservations[pendingChanID] = resCtx
}
}
}
f.resMtx.RUnlock()
for pendingChanID, resCtx := range zombieReservations {
err := fmt.Errorf("reservation timed out waiting for peer "+
"(peer_id:%v, chan_id:%x)", resCtx.peer.IdentityKey(),
pendingChanID[:])
fndgLog.Warnf(err.Error())
f.failFundingFlow(resCtx.peer, pendingChanID, err)
}
}
// cancelReservationCtx does all needed work in order to securely cancel the
// reservation.
func (f *fundingManager) cancelReservationCtx(peerKey *btcec.PublicKey,
pendingChanID [32]byte) (*reservationWithCtx, error) {
fndgLog.Infof("Cancelling funding reservation for node_key=%x, "+
"chan_id=%x", peerKey.SerializeCompressed(), pendingChanID[:])
peerIDKey := newSerializedKey(peerKey)
f.resMtx.Lock()
defer f.resMtx.Unlock()
nodeReservations, ok := f.activeReservations[peerIDKey]
if !ok {
// No reservations for this node.
return nil, errors.Errorf("no active reservations for peer(%x)",
peerIDKey[:])
}
ctx, ok := nodeReservations[pendingChanID]
if !ok {
return nil, errors.Errorf("unknown channel (id: %x) for "+
"peer(%x)", pendingChanID[:], peerIDKey[:])
}
if err := ctx.reservation.Cancel(); err != nil {
return nil, errors.Errorf("unable to cancel reservation: %v",
err)
}
delete(nodeReservations, pendingChanID)
// If this was the last active reservation for this peer, delete the
// peer's entry altogether.
if len(nodeReservations) == 0 {
delete(f.activeReservations, peerIDKey)
}
return ctx, nil
}
// deleteReservationCtx deletes the reservation uniquely identified by the
// target public key of the peer, and the specified pending channel ID.
func (f *fundingManager) deleteReservationCtx(peerKey *btcec.PublicKey,
pendingChanID [32]byte) {
// TODO(roasbeef): possibly cancel funding barrier in peer's
// channelManager?
peerIDKey := newSerializedKey(peerKey)
f.resMtx.Lock()
defer f.resMtx.Unlock()
nodeReservations, ok := f.activeReservations[peerIDKey]
if !ok {
// No reservations for this node.
return
}
delete(nodeReservations, pendingChanID)
// If this was the last active reservation for this peer, delete the
// peer's entry altogether.
if len(nodeReservations) == 0 {
delete(f.activeReservations, peerIDKey)
}
}
// getReservationCtx returns the reservation context for a particular pending
// channel ID for a target peer.
func (f *fundingManager) getReservationCtx(peerKey *btcec.PublicKey,
pendingChanID [32]byte) (*reservationWithCtx, error) {
peerIDKey := newSerializedKey(peerKey)
f.resMtx.RLock()
resCtx, ok := f.activeReservations[peerIDKey][pendingChanID]
f.resMtx.RUnlock()
if !ok {
return nil, errors.Errorf("unknown channel (id: %x) for "+
"peer(%x)", pendingChanID[:], peerIDKey[:])
}
return resCtx, nil
}
// IsPendingChannel returns a boolean indicating whether the channel identified
// by the pendingChanID and given peer is pending, meaning it is in the process
// of being funded. After the funding transaction has been confirmed, the
// channel will receive a new, permanent channel ID, and will no longer be
// considered pending.
func (f *fundingManager) IsPendingChannel(pendingChanID [32]byte,
peerKey *btcec.PublicKey) bool {
peerIDKey := newSerializedKey(peerKey)
f.resMtx.RLock()
_, ok := f.activeReservations[peerIDKey][pendingChanID]
f.resMtx.RUnlock()
return ok
}
func copyPubKey(pub *btcec.PublicKey) *btcec.PublicKey {
return &btcec.PublicKey{
Curve: btcec.S256(),
X: pub.X,
Y: pub.Y,
}
}
// saveChannelOpeningState saves the channelOpeningState for the provided
// chanPoint to the channelOpeningStateBucket.
func (f *fundingManager) saveChannelOpeningState(chanPoint *wire.OutPoint,
state channelOpeningState, shortChanID *lnwire.ShortChannelID) error {
return kvdb.Update(f.cfg.Wallet.Cfg.Database, func(tx kvdb.RwTx) error {
bucket, err := tx.CreateTopLevelBucket(channelOpeningStateBucket)
if err != nil {
return err
}
var outpointBytes bytes.Buffer
if err = writeOutpoint(&outpointBytes, chanPoint); err != nil {
return err
}
// Save state and the uint64 representation of the shortChanID
// for later use.
scratch := make([]byte, 10)
byteOrder.PutUint16(scratch[:2], uint16(state))
byteOrder.PutUint64(scratch[2:], shortChanID.ToUint64())
return bucket.Put(outpointBytes.Bytes(), scratch)
})
}
// getChannelOpeningState fetches the channelOpeningState for the provided
// chanPoint from the database, or returns ErrChannelNotFound if the channel
// is not found.
func (f *fundingManager) getChannelOpeningState(chanPoint *wire.OutPoint) (
channelOpeningState, *lnwire.ShortChannelID, error) {
var state channelOpeningState
var shortChanID lnwire.ShortChannelID
err := kvdb.View(f.cfg.Wallet.Cfg.Database, func(tx kvdb.ReadTx) error {
bucket := tx.ReadBucket(channelOpeningStateBucket)
if bucket == nil {
// If the bucket does not exist, it means we never added
// a channel to the db, so return ErrChannelNotFound.
return ErrChannelNotFound
}
var outpointBytes bytes.Buffer
if err := writeOutpoint(&outpointBytes, chanPoint); err != nil {
return err
}
value := bucket.Get(outpointBytes.Bytes())
if value == nil {
return ErrChannelNotFound
}
state = channelOpeningState(byteOrder.Uint16(value[:2]))
shortChanID = lnwire.NewShortChanIDFromInt(byteOrder.Uint64(value[2:]))
return nil
})
if err != nil {
return 0, nil, err
}
return state, &shortChanID, nil
}
// deleteChannelOpeningState removes any state for chanPoint from the database.
func (f *fundingManager) deleteChannelOpeningState(chanPoint *wire.OutPoint) error {
return kvdb.Update(f.cfg.Wallet.Cfg.Database, func(tx kvdb.RwTx) error {
bucket := tx.ReadWriteBucket(channelOpeningStateBucket)
if bucket == nil {
return fmt.Errorf("Bucket not found")
}
var outpointBytes bytes.Buffer
if err := writeOutpoint(&outpointBytes, chanPoint); err != nil {
return err
}
return bucket.Delete(outpointBytes.Bytes())
})
}