lnd.xprv/fundingmanager.go
Wilmer Paulino 760f38736e
fundingmanager: populate additional edge info after adding to graph
This commit serves as another stop-gap for light clients since they are
unable to obtain the capacity and channel point of graph edges. Since
they're aware of these things for their own channels, they can populate
the information within the graph themselves once each channel has been
successfully added to the graph.
2019-04-18 21:57:40 -07:00

3168 lines
107 KiB
Go

package main
import (
"bytes"
"encoding/binary"
"fmt"
"sync"
"sync/atomic"
"time"
"github.com/btcsuite/btcd/btcec"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
"github.com/coreos/bbolt"
"github.com/davecgh/go-spew/spew"
"github.com/go-errors/errors"
"github.com/lightningnetwork/lnd/chainntnfs"
"github.com/lightningnetwork/lnd/channeldb"
"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/lnwire"
"github.com/lightningnetwork/lnd/routing"
"golang.org/x/crypto/salsa20"
"google.golang.org/grpc"
)
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 about
// the channel. 288 blocks is ~48 hrs
maxWaitNumBlocksFundingConf = 288
// 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")
)
// 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()
}
// lock locks the reservation from zombie pruning by setting its timestamp to the
// zero value.
func (r *reservationWithCtx) lock() {
r.updateMtx.Lock()
defer r.updateMtx.Unlock()
r.lastUpdated = time.Time{}
}
// 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 lnwallet.FeeEstimator
// 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 method 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 *btcec.PublicKey, 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
// 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
// NotifyOpenChannelEvent informs the ChannelNotifier when channels
// transition from pending open to open.
NotifyOpenChannelEvent func(wire.OutPoint)
}
// 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 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 {
// MUST be used atomically.
started int32
stopped int32
// 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 {
if atomic.AddInt32(&f.started, 1) != 1 { // TODO(roasbeef): CAS instead
return nil
}
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
pendingChannels, err := f.cfg.Wallet.Cfg.Database.FetchPendingChannels()
if err != nil {
return err
}
// 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 will also launch waitForFundingConfirmation to wait for
// the channel's funding transaction to be confirmed on the blockchain.
for _, channel := range pendingChannels {
f.barrierMtx.Lock()
fndgLog.Tracef("Loading pending ChannelPoint(%v), creating chan "+
"barrier", channel.FundingOutpoint)
chanID := lnwire.NewChanIDFromOutPoint(&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. If this operation fails due to a reported
// double spend, we treat this as an indicator that we have
// already broadcast this transaction. Otherwise, we simply log
// the error as there isn't anything we can currently do to
// recover.
if channel.ChanType == channeldb.SingleFunder &&
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)
}
}
confChan := make(chan *lnwire.ShortChannelID)
timeoutChan := make(chan struct{})
go func(ch *channeldb.OpenChannel) {
go f.waitForFundingWithTimeout(ch, confChan, timeoutChan)
select {
case <-timeoutChan:
// Timeout channel will be triggered if the number of blocks
// mined since the channel was initiated reaches
// maxWaitNumBlocksFundingConf and we are not the channel
// initiator.
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,
}
if err := ch.CloseChannel(closeInfo); err != nil {
fndgLog.Errorf("Failed closing channel "+
"%v: %v", ch.FundingOutpoint, err)
}
case <-f.quit:
// The fundingManager is shutting down, and will
// resume wait on startup.
case shortChanID, ok := <-confChan:
if !ok {
fndgLog.Errorf("Waiting for funding" +
"confirmation failed")
return
}
// The funding transaction has confirmed, so
// we'll attempt to retrieve the remote peer
// to complete the rest of the funding flow.
peerChan := make(chan lnpeer.Peer, 1)
f.cfg.NotifyWhenOnline(ch.IdentityPub, peerChan)
var peer lnpeer.Peer
select {
case peer = <-peerChan:
case <-f.quit:
return
}
err := f.handleFundingConfirmation(
peer, ch, shortChanID,
)
if err != nil {
fndgLog.Errorf("Failed to handle "+
"funding confirmation: %v", err)
return
}
}
}(channel)
}
// Fetch all our open channels, and make sure they all finalized the
// opening process.
// TODO(halseth): this check is only done on restart atm, but should
// also be done if a peer that disappeared during the opening process
// reconnects.
openChannels, err := f.cfg.Wallet.Cfg.Database.FetchAllChannels()
if err != nil {
return err
}
for _, channel := range openChannels {
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.
continue
} else if err != nil {
return err
}
chanID := lnwire.NewChanIDFromOutPoint(&channel.FundingOutpoint)
fndgLog.Debugf("channel (%v) with opening state %v found",
chanID, channelState)
if channel.IsPending {
// Set up the channel barriers again, to make sure
// waitUntilChannelOpen correctly waits until the
// opening process is completely over.
f.barrierMtx.Lock()
fndgLog.Tracef("Loading pending ChannelPoint(%v), "+
"creating chan barrier", channel.FundingOutpoint)
f.newChanBarriers[chanID] = make(chan struct{})
f.barrierMtx.Unlock()
}
// If we did find the channel in the opening state database, we
// have seen the funding transaction being confirmed, but we
// did not finish the rest of the setup procedure before we shut
// down. We handle the remaining steps of this setup by
// continuing the procedure where we left off.
switch channelState {
case markedOpen:
// The funding transaction was confirmed, but we did not
// successfully send the fundingLocked message to the
// peer, so let's do that now.
f.wg.Add(1)
go func(dbChan *channeldb.OpenChannel) {
defer f.wg.Done()
peerChan := make(chan lnpeer.Peer, 1)
f.cfg.NotifyWhenOnline(dbChan.IdentityPub, peerChan)
var peer lnpeer.Peer
select {
case peer = <-peerChan:
case <-f.quit:
return
}
err := f.handleFundingConfirmation(
peer, dbChan, shortChanID,
)
if err != nil {
fndgLog.Errorf("Failed to handle "+
"funding confirmation: %v", err)
return
}
}(channel)
case fundingLockedSent:
// fundingLocked was sent to peer, but the channel
// was not added to the router graph and the channel
// announcement was not sent.
f.wg.Add(1)
go func(dbChan *channeldb.OpenChannel) {
defer f.wg.Done()
err = f.addToRouterGraph(dbChan, shortChanID)
if err != nil {
fndgLog.Errorf("failed adding to "+
"router graph: %v", err)
return
}
// TODO(halseth): should create a state machine
// that can more easily be resumed from
// different states, to avoid this code
// duplication.
err = f.annAfterSixConfs(dbChan, shortChanID)
if err != nil {
fndgLog.Errorf("error sending channel "+
"announcements: %v", err)
return
}
}(channel)
case addedToRouterGraph:
// The channel was added to the Router's topology, but
// the channel announcement was not sent.
f.wg.Add(1)
go func(dbChan *channeldb.OpenChannel) {
defer f.wg.Done()
err = f.annAfterSixConfs(dbChan, shortChanID)
if err != nil {
fndgLog.Errorf("error sending channel "+
"announcement: %v", err)
return
}
}(channel)
default:
fndgLog.Errorf("undefined channelState: %v",
channelState)
}
}
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 {
if atomic.AddInt32(&f.stopped, 1) != 1 {
return nil
}
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 pendingID=%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.ErrorCode or lnwallet.ReservationError).
var msg lnwire.ErrorData
switch e := fundingErr.(type) {
// Let the actual error message be sent to the remote.
case lnwallet.ReservationError:
msg = lnwire.ErrorData(e.Error())
// Send the status code.
case lnwire.ErrorCode:
msg = lnwire.ErrorData{byte(e)}
// 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
}
}
}
// 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
}
}
// 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 >= 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 cfg.RejectPush && msg.PushAmount > 0 {
f.failFundingFlow(
fmsg.peer, fmsg.msg.PendingChannelID,
lnwallet.ErrNonZeroPushAmount())
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.
chainHash := chainhash.Hash(msg.ChainHash)
req := &lnwallet.InitFundingReserveMsg{
ChainHash: &chainHash,
NodeID: fmsg.peer.IdentityKey(),
NodeAddr: fmsg.peer.Address(),
FundingAmount: 0,
Capacity: amt,
CommitFeePerKw: lnwallet.SatPerKWeight(msg.FeePerKiloWeight),
FundingFeePerKw: 0,
PushMSat: msg.PushAmount,
Flags: msg.ChannelFlags,
MinConfs: 1,
}
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 out 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
}
fndgLog.Infof("Requiring %v confirmations for pendingChan(%x): "+
"amt=%v, push_amt=%v", numConfsReq, fmsg.msg.PendingChannelID,
amt, msg.PushAmount)
// 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.DefaultRoutingPolicy.MinHTLC
// 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),
},
},
}
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 pendingID(%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,
}
if err := fmsg.peer.SendMessage(false, &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, chanID:%v)",
peerKey, pendingChanID)
return
}
// Update the timestamp once the fundingAcceptMsg has been handled.
defer resCtx.updateTimestamp()
fndgLog.Infof("Recv'd fundingResponse for pendingID(%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),
},
},
}
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 pendingID(%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(false, 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 (peerID:%v, chanID:%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 pendingID(%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,
}
if err := completeChan.CloseChannel(closeInfo); 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 pendingID(%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(false, 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()
// 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 func() {
defer f.wg.Done()
confChan := make(chan *lnwire.ShortChannelID)
timeoutChan := make(chan struct{})
go f.waitForFundingWithTimeout(completeChan, confChan,
timeoutChan)
var shortChanID *lnwire.ShortChannelID
var ok bool
select {
case <-timeoutChan:
// We did not see the funding confirmation before
// timeout, so we forget the channel.
err := fmt.Errorf("timeout waiting for funding tx "+
"(%v) to confirm", completeChan.FundingOutpoint)
fndgLog.Warnf(err.Error())
f.failFundingFlow(fmsg.peer, pendingChanID, err)
deleteFromDatabase()
return
case <-f.quit:
// The fundingManager is shutting down, will resume
// wait for funding transaction on startup.
return
case shortChanID, ok = <-confChan:
if !ok {
fndgLog.Errorf("waiting for funding confirmation" +
" failed")
return
}
// Fallthrough.
}
// Success, funding transaction was confirmed.
err := f.handleFundingConfirmation(
fmsg.peer, completeChan, shortChanID,
)
if err != nil {
fndgLog.Errorf("failed to handle funding"+
"confirmation: %v", err)
return
}
}()
}
// 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 (peerID:%v, chanID:%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.
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-chin 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 pendingID(%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,
},
},
}
select {
case resCtx.updates <- upd:
case <-f.quit:
return
}
// At this point we have broadcast the funding transaction and done all
// necessary processing.
f.wg.Add(1)
go func() {
defer f.wg.Done()
confChan := make(chan *lnwire.ShortChannelID)
cancelChan := make(chan struct{})
// In case the fundingManager is stopped at some point during
// the remaining part of the opening process, we must wait for
// this process to finish (either successfully or with some
// error), before the fundingManager can be shut down.
f.wg.Add(1)
go func() {
defer f.wg.Done()
f.waitForFundingConfirmation(completeChan, cancelChan,
confChan)
}()
var shortChanID *lnwire.ShortChannelID
var ok bool
select {
case <-f.quit:
return
case shortChanID, ok = <-confChan:
if !ok {
fndgLog.Errorf("waiting for funding confirmation" +
" failed")
return
}
}
fndgLog.Debugf("Channel with ShortChanID %v now confirmed",
shortChanID.ToUint64())
// Go on adding the channel to the channel graph, and crafting
// channel announcements.
lnChannel, err := lnwallet.NewLightningChannel(
nil, nil, completeChan, nil,
)
if err != nil {
fndgLog.Errorf("failed creating lnChannel: %v", err)
return
}
err = f.sendFundingLocked(
fmsg.peer, completeChan, lnChannel, shortChanID,
)
if err != nil {
fndgLog.Errorf("failed sending fundingLocked: %v", err)
return
}
fndgLog.Debugf("FundingLocked for channel with ShortChanID "+
"%v sent", shortChanID.ToUint64())
err = f.addToRouterGraph(completeChan, shortChanID)
if err != nil {
fndgLog.Errorf("failed adding to router graph: %v", err)
return
}
fndgLog.Debugf("Channel with ShortChanID %v added to "+
"router graph", shortChanID.ToUint64())
// Give the caller a final update notifying them that
// the channel is now open.
// TODO(roasbeef): only notify after recv of funding locked?
upd := &lnrpc.OpenStatusUpdate{
Update: &lnrpc.OpenStatusUpdate_ChanOpen{
ChanOpen: &lnrpc.ChannelOpenUpdate{
ChannelPoint: &lnrpc.ChannelPoint{
FundingTxid: &lnrpc.ChannelPoint_FundingTxidBytes{
FundingTxidBytes: fundingPoint.Hash[:],
},
OutputIndex: fundingPoint.Index,
},
},
},
}
select {
case resCtx.updates <- upd:
case <-f.quit:
return
}
err = f.annAfterSixConfs(completeChan, shortChanID)
if err != nil {
fndgLog.Errorf("failed sending channel announcement: %v",
err)
return
}
}()
}
// waitForFundingWithTimeout is a wrapper around waitForFundingConfirmation that
// will cancel the wait for confirmation if we are not the channel initiator and
// the maxWaitNumBlocksFundingConf has passed from bestHeight.
// In the case of timeout, the timeoutChan will be closed. In case of error,
// confChan will be closed. In case of success, a *lnwire.ShortChannelID will be
// passed to confChan.
func (f *fundingManager) waitForFundingWithTimeout(completeChan *channeldb.OpenChannel,
confChan chan<- *lnwire.ShortChannelID, timeoutChan chan<- struct{}) {
epochClient, err := f.cfg.Notifier.RegisterBlockEpochNtfn(nil)
if err != nil {
fndgLog.Errorf("unable to register for epoch notification: %v",
err)
close(confChan)
return
}
defer epochClient.Cancel()
waitingConfChan := make(chan *lnwire.ShortChannelID)
cancelChan := make(chan struct{})
// Add this goroutine to wait group so we can be sure that it is
// properly stopped before the funding manager can be shut down.
f.wg.Add(1)
go func() {
defer f.wg.Done()
f.waitForFundingConfirmation(completeChan, cancelChan,
waitingConfChan)
}()
// On block maxHeight we will cancel the funding confirmation wait.
maxHeight := completeChan.FundingBroadcastHeight + maxWaitNumBlocksFundingConf
for {
select {
case epoch, ok := <-epochClient.Epochs:
if !ok {
fndgLog.Warnf("Epoch client shutting down")
return
}
// If we are not the channel initiator it's safe
// to timeout the channel
if uint32(epoch.Height) >= maxHeight && !completeChan.IsInitiator {
fndgLog.Warnf("waited for %v blocks without "+
"seeing funding transaction confirmed,"+
" cancelling.", maxWaitNumBlocksFundingConf)
// Cancel the waitForFundingConfirmation
// goroutine.
close(cancelChan)
// 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 <-f.quit:
// The fundingManager is shutting down, will resume
// waiting for the funding transaction on startup.
return
case shortChanID, ok := <-waitingConfChan:
if !ok {
// Failed waiting for confirmation, close
// confChan to indicate failure.
close(confChan)
return
}
select {
case confChan <- shortChanID:
case <-f.quit:
return
}
}
}
}
// 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.
func (f *fundingManager) waitForFundingConfirmation(completeChan *channeldb.OpenChannel,
cancelChan <-chan struct{}, confChan chan<- *lnwire.ShortChannelID) {
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
chanID := lnwire.NewChanIDFromOutPoint(&fundingPoint)
fndgLog.Infof("ChannelPoint(%v) is now active: ChannelID(%x)",
fundingPoint, chanID[:])
// 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),
}
// Now that the channel has been fully confirmed, we'll mark it as open
// within the database.
if err := completeChan.MarkAsOpen(shortChanID); err != nil {
fndgLog.Errorf("error setting channel pending flag to false: "+
"%v", err)
return
}
// Inform the ChannelNotifier that the channel has transitioned from
// pending open to open.
f.cfg.NotifyOpenChannelEvent(completeChan.FundingOutpoint)
// TODO(roasbeef): ideally persistent state update for chan above
// should be abstracted
// 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.
//
// TODO(halseth): make the two db transactions (MarkChannelAsOpen and
// saveChannelOpeningState) atomic by doing them in the same transaction.
// Needed to be properly fault-tolerant.
err = f.saveChannelOpeningState(&completeChan.FundingOutpoint, markedOpen,
&shortChanID)
if err != nil {
fndgLog.Errorf("error setting channel state to markedOpen: %v",
err)
return
}
// 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)
}
select {
case confChan <- &shortChanID:
case <-f.quit:
return
}
// 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()
}
// handleFundingConfirmation is a wrapper method for creating a new
// lnwallet.LightningChannel object, calling sendFundingLocked,
// addToRouterGraph, and annAfterSixConfs. This is called after the funding
// transaction is confirmed.
func (f *fundingManager) handleFundingConfirmation(peer lnpeer.Peer,
completeChan *channeldb.OpenChannel,
shortChanID *lnwire.ShortChannelID) error {
// We create the state-machine object which wraps the database state.
lnChannel, err := lnwallet.NewLightningChannel(
nil, nil, completeChan, nil,
)
if err != nil {
return err
}
chanID := lnwire.NewChanIDFromOutPoint(&completeChan.FundingOutpoint)
fndgLog.Debugf("ChannelID(%v) is now fully confirmed!", chanID)
err = f.sendFundingLocked(peer, completeChan, lnChannel, shortChanID)
if err != nil {
return fmt.Errorf("failed sending fundingLocked: %v", err)
}
err = f.addToRouterGraph(completeChan, shortChanID)
if err != nil {
return fmt.Errorf("failed adding to router graph: %v", err)
}
err = f.annAfterSixConfs(completeChan, shortChanID)
if err != nil {
return fmt.Errorf("failed sending channel announcement: %v",
err)
}
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(peer lnpeer.Peer,
completeChan *channeldb.OpenChannel, channel *lnwallet.LightningChannel,
shortChanID *lnwire.ShortChannelID) error {
chanID := lnwire.NewChanIDFromOutPoint(&completeChan.FundingOutpoint)
peerKey := completeChan.IdentityPub
// 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 {
fndgLog.Debugf("Sending FundingLocked for ChannelID(%v) to "+
"peer %x", chanID, peerKey.SerializeCompressed())
if err := peer.SendMessage(false, 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.SerializeCompressed(),
err)
connected := make(chan lnpeer.Peer, 1)
f.cfg.NotifyWhenOnline(completeChan.IdentityPub, connected)
select {
case <-connected:
fndgLog.Infof("Peer(%x) came back online, will retry "+
"sending FundingLocked for ChannelID(%v)",
peerKey.SerializeCompressed(), chanID)
// Retry sending.
case <-f.quit:
return ErrFundingManagerShuttingDown
}
}
// 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(&completeChan.FundingOutpoint,
fundingLockedSent, shortChanID)
if err != nil {
return fmt.Errorf("error setting channel state to"+
" fundingLockedSent: %v", 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'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
}
// 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(&completeChan.FundingOutpoint,
addedToRouterGraph, shortChanID)
if err != nil {
return fmt.Errorf("error setting channel state to"+
" addedToRouterGraph: %v", err)
}
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)
f.cfg.NotifyWhenOnline(completeChan.IdentityPub, 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)
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)
// 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'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
}
// 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, fwdMinHTLC, fwdMaxHTLC,
)
if err != nil {
return fmt.Errorf("channel announcement failed: %v", err)
}
fndgLog.Debugf("Channel with ChannelPoint(%v), short_chan_id=%v "+
"announced", &fundingPoint, shortChanID)
}
// 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(&completeChan.FundingOutpoint)
if err != nil {
return fmt.Errorf("error deleting channel state: %v", err)
}
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 who's funding workflow is
// being finalized by this message. We got 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 not longer online at this point.
defer func() {
// Close the active channel barrier signalling 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)
}
}
// channelProof is one half of the proof necessary to create an authenticated
// announcement on the network. The two signatures individually sign a
// statement of the existence of a channel.
type channelProof struct {
nodeSig *btcec.Signature
bitcoinSig *btcec.Signature
}
// 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, fwdMinHTLC, fwdMaxHTLC lnwire.MilliSatoshi) 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.
ann, err := f.newChanAnnouncement(localIDKey, remoteIDKey,
localFundingKey, remoteFundingKey, shortChanID, chanID,
fwdMinHTLC, fwdMaxHTLC,
)
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 send 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,
}
}
// 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
remoteAmt = msg.remoteFundingAmt
capacity = localAmt + remoteAmt
minHtlc = msg.minHtlc
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(localAmt=%v, remoteAmt=%v, "+
"capacity=%v, chainhash=%v, peer=%x, dustLimit=%v, min_confs=%v)",
localAmt, msg.pushAmt, capacity, 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
}
// 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.
req := &lnwallet.InitFundingReserveMsg{
ChainHash: &msg.chainHash,
NodeID: peerKey,
NodeAddr: msg.peer.Address(),
FundingAmount: localAmt,
Capacity: capacity,
CommitFeePerKw: commitFeePerKw,
FundingFeePerKw: msg.fundingFeePerKw,
PushMSat: msg.pushAmt,
Flags: channelFlags,
MinConfs: msg.minConfs,
}
reservation, err := f.cfg.Wallet.InitChannelReservation(req)
if err != nil {
msg.err <- err
return
}
// Obtain a new pending channel ID which is used to track this
// reservation throughout its lifetime.
chanID := f.nextPendingChanID()
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 minHtlc == 0 {
minHtlc = f.cfg.DefaultRoutingPolicy.MinHTLC
}
// 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: minHtlc,
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 pendingID(%x)",
msg.peer.Address(), chanID)
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: minHtlc,
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,
}
if err := msg.peer.SendMessage(false, &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, spew.Sdump(protocolErr))
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.
lnErr := lnwire.ErrorCode(protocolErr.Data[0])
fndgLog.Errorf("Received funding error from %x: %v",
fmsg.peerKey.SerializeCompressed(), string(protocolErr.Data),
)
// If this isn't a simple error code, then we'll display the entire
// thing.
if len(protocolErr.Data) > 1 {
err = grpc.Errorf(
lnErr.ToGrpcCode(), string(protocolErr.Data),
)
} else {
// Otherwise, we'll attempt to display just the error code
// itself.
err = grpc.Errorf(
lnErr.ToGrpcCode(), lnErr.String(),
)
}
resCtx.err <- err
}
// 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 "+
"(peerID:%v, chanID:%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 f.cfg.Wallet.Cfg.Database.Update(func(tx *bbolt.Tx) error {
bucket, err := tx.CreateBucketIfNotExists(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 := f.cfg.Wallet.Cfg.Database.View(func(tx *bbolt.Tx) error {
bucket := tx.Bucket(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 f.cfg.Wallet.Cfg.Database.Update(func(tx *bbolt.Tx) error {
bucket := tx.Bucket(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())
})
}