lnd/fundingmanager.go

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package main
import (
"sync"
"sync/atomic"
"github.com/lightningnetwork/lnd/lnwallet"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/roasbeef/btcd/btcec"
"github.com/roasbeef/btcd/txscript"
"github.com/roasbeef/btcd/wire"
)
const (
// TODO(roasbeef): tune
msgBufferSize = 50
)
// 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 meethods 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
resp chan *wire.OutPoint
err chan error
}
// initFundingMsg is sent by an outside sub-system 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 *peer
err chan error
resp chan *wire.OutPoint
*openChanReq
}
// fundingRequestMsg couples an lnwire.SingleFundingRequest 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 fundingRequestMsg struct {
msg *lnwire.SingleFundingRequest
peer *peer
}
// fundingResponseMsg couples an lnwire.SingleFundingResponse 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 fundingResponseMsg struct {
msg *lnwire.SingleFundingResponse
peer *peer
}
// fundingCompleteMsg couples an lnwire.SingleFundingComplete 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 fundingCompleteMsg struct {
msg *lnwire.SingleFundingComplete
peer *peer
}
// fundingSignCompleteMsg couples an lnwire.SingleFundingSignComplete 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 fundingSignCompleteMsg struct {
msg *lnwire.SingleFundingSignComplete
peer *peer
}
// fundingOpenMsg couples an lnwire.SingleFundingOpenProof 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.SingleFundingOpenProof
peer *peer
}
// pendingChannels is a map instantiated per-peer which tracks all active
// pending single funded channels indexed by their pending channel identifier.
type pendingChannels map[uint64]*reservationWithCtx
// fundingManager acts as an orchestrator/bridge between the wallet's
// 'ChannelReservation' workflow, and the wire protocl's funding initiation
// messages. Any requests to initaite the funding workflow for a channel, either
// kicked-off locally, or remotely is handled by the funding manager. Once a
// channels'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
// channelReservations is a map which houses the state of all pending
// funding workflows.
resMtx sync.RWMutex
activeReservations map[int32]pendingChannels
// wallet is the daemon's internal Lightning enabled wallet.
wallet *lnwallet.LightningWallet
// fundingMsgs is a channel which receives wrapped wire messages
// related to funding workflow from outside peers.
fundingMsgs chan interface{}
// fundingRequests is a channel used to recieve channel initiation
// requests from a local sub-system within the daemon.
fundingRequests chan *initFundingMsg
quit chan struct{}
wg sync.WaitGroup
}
// newFundingManager creates and initializes a new instance of the
// fundingManager.
func newFundingManager(w *lnwallet.LightningWallet) *fundingManager {
return &fundingManager{
activeReservations: make(map[int32]pendingChannels),
wallet: w,
fundingMsgs: make(chan interface{}, msgBufferSize),
fundingRequests: make(chan *initFundingMsg, msgBufferSize),
quit: make(chan struct{}),
}
}
// 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.Infof("funding manager running")
f.wg.Add(1) // TODO(roasbeef): tune
go f.reservationCoordinator()
return nil
}
// Start 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
}
// 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() {
out:
for {
select {
case msg := <-f.fundingMsgs:
switch fmsg := msg.(type) {
case *fundingRequestMsg:
f.handleFundingRequest(fmsg)
case *fundingResponseMsg:
f.handleFundingResponse(fmsg)
case *fundingCompleteMsg:
f.handleFundingComplete(fmsg)
case *fundingSignCompleteMsg:
f.handleFundingSignComplete(fmsg)
case *fundingOpenMsg:
f.handleFundingOpen(fmsg)
}
case req := <-f.fundingRequests:
f.handleInitFundingMsg(req)
case <-f.quit:
break out
}
}
f.wg.Done()
}
// processFundingRequest sends a message to the fundingManager allowing it to
// intiate the new funding workflow with the source peer.
func (f *fundingManager) processFundingRequest(msg *lnwire.SingleFundingRequest, peer *peer) {
f.fundingMsgs <- &fundingRequestMsg{msg, peer}
}
// handleSingleFundingRequest creates an initial 'ChannelReservation' within
// the wallet, then responds to the source peer with a single funder response
// message progressing the funding workflow.
// TODO(roasbeef): add erorr chan to all, let channelManager handle
// error+propagate
func (f *fundingManager) handleFundingRequest(fmsg *fundingRequestMsg) {
msg := fmsg.msg
amt := msg.FundingAmount
delay := msg.CsvDelay
fndgLog.Infof("Recv'd fundingRequest(amt=%v, delay=%v, pendingId=%v) "+
"from peerID(%v)", amt, delay, msg.ChannelID, fmsg.peer.id)
// 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.
// TODO(roasbeef): passing num confs 1 is irrelevant here, make signed?
reservation, err := f.wallet.InitChannelReservation(amt, 0, fmsg.peer.lightningID, 1, delay)
if err != nil {
fndgLog.Errorf("Unable to initialize reservation: %v", err)
return
}
// Once the reservation has been created succesfully, we add it to this
// peers map of pending reservations to track this particular reservation
// until either abort or completion.
f.resMtx.Lock()
if _, ok := f.activeReservations[fmsg.peer.id]; !ok {
f.activeReservations[fmsg.peer.id] = make(pendingChannels)
}
f.activeReservations[fmsg.peer.id][msg.ChannelID] = &reservationWithCtx{
reservation: reservation,
}
f.resMtx.Unlock()
// With our portion of the reservation initialied, process the
// initiators contribution to the channel.
_, addrs, _, err := txscript.ExtractPkScriptAddrs(msg.DeliveryPkScript, activeNetParams)
if err != nil {
fndgLog.Errorf("Unable to extract addresses from script: %v", err)
return
}
contribution := &lnwallet.ChannelContribution{
FundingAmount: amt,
MultiSigKey: msg.ChannelDerivationPoint,
CommitKey: msg.CommitmentKey,
DeliveryAddress: addrs[0],
RevocationHash: msg.RevocationHash,
CsvDelay: delay,
}
if err := reservation.ProcessSingleContribution(contribution); err != nil {
fndgLog.Errorf("unable to add contribution reservation: %v", err)
return
}
fndgLog.Infof("Sending fundingResp for pendingID(%v)", msg.ChannelID)
// With the initiator's contribution recorded, response with our
// contribution in the next message of the workflow.
ourContribution := reservation.OurContribution()
deliveryScript, err := txscript.PayToAddrScript(ourContribution.DeliveryAddress)
if err != nil {
fndgLog.Errorf("unable to convert address to pkscript: %v", err)
return
}
fundingResp := lnwire.NewSingleFundingResponse(msg.ChannelID,
ourContribution.RevocationHash, ourContribution.CommitKey,
ourContribution.MultiSigKey, ourContribution.CsvDelay,
deliveryScript)
fmsg.peer.queueMsg(fundingResp, nil)
}
// processFundingRequest sends a message to the fundingManager allowing it to
// continue the second phase of a funding workflow with the target peer.
func (f *fundingManager) processFundingResponse(msg *lnwire.SingleFundingResponse, peer *peer) {
f.fundingMsgs <- &fundingResponseMsg{msg, peer}
}
// handleFundingResponse 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) handleFundingResponse(fmsg *fundingResponseMsg) {
msg := fmsg.msg
sourcePeer := fmsg.peer
f.resMtx.RLock()
resCtx := f.activeReservations[fmsg.peer.id][msg.ChannelID]
f.resMtx.RUnlock()
fndgLog.Infof("Recv'd fundingResponse for pendingID(%v)", msg.ChannelID)
// 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.
_, addrs, _, err := txscript.ExtractPkScriptAddrs(msg.DeliveryPkScript, activeNetParams)
if err != nil {
fndgLog.Errorf("Unable to extract addresses from script: %v", err)
return
}
contribution := &lnwallet.ChannelContribution{
FundingAmount: 0,
MultiSigKey: msg.ChannelDerivationPoint,
CommitKey: msg.CommitmentKey,
DeliveryAddress: addrs[0],
RevocationHash: msg.RevocationHash,
CsvDelay: msg.CsvDelay,
}
if err := resCtx.reservation.ProcessContribution(contribution); err != nil {
fndgLog.Errorf("Unable to process contribution from %v: %v",
sourcePeer, err)
return
}
// TODO(roasbeef): create new chan barrier
// 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()
commitSig, err := btcec.ParseSignature(sig, btcec.S256())
if err != nil {
fndgLog.Errorf("Unable to parse signature: %v", err)
return
}
fndgLog.Infof("Generated ChannelPoint(%v) for pendingID(%v)",
outPoint, msg.ChannelID)
fundingComplete := lnwire.NewSingleFundingComplete(msg.ChannelID,
outPoint, commitSig)
sourcePeer.queueMsg(fundingComplete, nil)
}
// processFundingComplete queues a funding complete message coupled with the
// source peer to the fundingManager.
func (f *fundingManager) processFundingComplete(msg *lnwire.SingleFundingComplete, peer *peer) {
f.fundingMsgs <- &fundingCompleteMsg{msg, peer}
}
// handleFundingComplete 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) handleFundingComplete(fmsg *fundingCompleteMsg) {
f.resMtx.RLock()
resCtx := f.activeReservations[fmsg.peer.id][fmsg.msg.ChannelID]
f.resMtx.RUnlock()
// 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
// inititator's commitment transaction, then send our own if it's valid.
// TODO(roasbeef): make case (p vs P) consistent throughout
fundingOut := fmsg.msg.FundingOutPoint
chanID := fmsg.msg.ChannelID
commitSig := fmsg.msg.CommitSignature.Serialize()
fndgLog.Infof("completing pendingID(%v) with ChannelPoint(%v)",
fmsg.msg.ChannelID, fundingOut,
)
// Append a sighash type of SigHashAll to the signature as it's the
// sighash type used implicitly within this type of channel for
// commitment transactions.
commitSig = append(commitSig, byte(txscript.SigHashAll))
if err := resCtx.reservation.CompleteReservationSingle(fundingOut, commitSig); err != nil {
// TODO(roasbeef): better error logging: peerID, channelID, etc.
fndgLog.Errorf("unable to complete single reservation: %v", err)
return
}
// With their signature for our version of the commitment transaction
// verified, we can now send over our signature to the remote peer.
// TODO(roasbeef): just have raw bytes in wire msg? avoids decoding
// then decoding shortly afterwards.
_, sig := resCtx.reservation.OurSignatures()
ourCommitSig, err := btcec.ParseSignature(sig, btcec.S256())
if err != nil {
fndgLog.Errorf("unable to parse signature: %v", err)
return
}
// TODO(roasbeef): create new chan barrier
fndgLog.Infof("sending signComplete for pendingID(%v) over ChannelPoint(%v)",
fmsg.msg.ChannelID, fundingOut)
signComplete := lnwire.NewSingleFundingSignComplete(chanID, ourCommitSig)
fmsg.peer.queueMsg(signComplete, nil)
}
// processFundingSignComplete sends a single funding sign complete message
// along with the source peer to the funding manager.
func (f *fundingManager) processFundingSignComplete(msg *lnwire.SingleFundingSignComplete, peer *peer) {
f.fundingMsgs <- &fundingSignCompleteMsg{msg, peer}
}
// handleFundingSignComplete processes the final message recieved 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 an SPV
// proofs of transaction inclusion.
func (f *fundingManager) handleFundingSignComplete(fmsg *fundingSignCompleteMsg) {
chanID := fmsg.msg.ChannelID
f.resMtx.RLock()
resCtx := f.activeReservations[fmsg.peer.id][chanID]
f.resMtx.RUnlock()
// 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 := append(fmsg.msg.CommitSignature.Serialize(), byte(txscript.SigHashAll))
if err := resCtx.reservation.CompleteReservation(nil, commitSig); err != nil {
fndgLog.Errorf("unable to complete reservation sign complete: %v", err)
return
}
// This reservation is no longer pending as the funding transaction has been
// broadcast, so we can now delete it.
f.resMtx.Lock()
delete(f.activeReservations[fmsg.peer.id], chanID)
f.resMtx.Unlock()
fundingPoint := resCtx.reservation.FundingOutpoint()
fndgLog.Infof("Finalizing pendingID(%v) over ChannelPoint(%v), "+
"waiting for channel open on-chain", chanID, fundingPoint)
// Spawn a goroutine which will send the newly open channel to the
// source peer once the channel is open. A channel is considered "open"
// once it reaches a sufficient number of confirmations.
go func() {
// TODO(roasbeef): semaphore to limit active chan open goroutines
select {
case openChan := <-resCtx.reservation.DispatchChan():
fndgLog.Infof("ChannelPoint(%v) with peerID(%v) is now active",
fundingPoint, fmsg.peer.id)
// Now that the channel is open, we need to notifiy a
// number of parties of this event.
// First we send the newly opened channel to the source
// server peer.
fmsg.peer.newChannels <- openChan
// Next, we queue a message to notify the remote peer
// that the channel is open. We additionally provide an
// SPV proof allowing them to verify the transaction
// inclusion.
// TODO(roasbeef): obtain SPV proof from sub-system.
// * ChainNotifier constructs proof also?
spvProof := []byte("fake proof")
fundingOpen := lnwire.NewSingleFundingOpenProof(chanID, spvProof)
fmsg.peer.queueMsg(fundingOpen, nil)
// Finally, respond to the original caller (if any).
resCtx.err <- nil
resCtx.resp <- resCtx.reservation.FundingOutpoint()
return
case <-f.quit:
return
}
}()
}
// processFundingOpenProof sends a message to the fundingManager allowing it
// to process the final message recieved when the daemon is on the responding
// side of a single funder channel workflow.
func (f *fundingManager) processFundingOpenProof(msg *lnwire.SingleFundingOpenProof, peer *peer) {
f.fundingMsgs <- &fundingOpenMsg{msg, peer}
}
// handleFundingOpen processes the final message when the daemon is the
// responder to a single funder channel workflow. The SPV proofs supplied by
// the initiating node is verified, which if correct, marks the channel as open
// to the source peer.
func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
f.resMtx.RLock()
resCtx := f.activeReservations[fmsg.peer.id][fmsg.msg.ChannelID]
f.resMtx.RUnlock()
// The channel initiator has claimed the channel is now open, so we'll
// verify the contained SPV proof for validity.
// TODO(roasbeef): send off to the spv proof verifier, in the routing
// sub-module.
// Now that we've verified the initiator's proof, we'll commit the
// channel state to disk, and notify the source peer of a newly opened
// channel.
openChan, err := resCtx.reservation.FinalizeReservation()
if err != nil {
fndgLog.Errorf("unable to finalize reservation: %v", err)
return
}
// The reservation has been completed, therefore we can stop tracking
// it within our active reservations map.
f.resMtx.Lock()
delete(f.activeReservations[fmsg.peer.id], fmsg.msg.ChannelID)
f.resMtx.Unlock()
fndgLog.Infof("FundingOpen: ChannelPoint(%v) with peerID(%v) is now open",
resCtx.reservation.FundingOutpoint, fmsg.peer.id)
fmsg.peer.newChannels <- openChan
}
// 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(targetPeer *peer, req *openChanReq) (*wire.OutPoint, error) {
errChan := make(chan error, 1)
respChan := make(chan *wire.OutPoint, 1)
f.fundingRequests <- &initFundingMsg{
peer: targetPeer,
resp: respChan,
err: errChan,
openChanReq: req,
}
return <-respChan, <-errChan
}
// 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) {
nodeID := msg.peer.lightningID
localAmt := msg.localFundingAmt
remoteAmt := msg.remoteFundingAmt
capacity := localAmt + remoteAmt
numConfs := msg.numConfs
// TODO(roasbeef): add delay
fndgLog.Infof("Initiating fundingRequest(localAmt=%v, remoteAmt=%v, "+
"capacity=%v, numConfs=%v)", localAmt, remoteAmt, capacity, numConfs)
// 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.
reservation, err := f.wallet.InitChannelReservation(capacity, localAmt,
nodeID, uint16(numConfs), 4)
if err != nil {
msg.resp <- nil
msg.err <- err
return
}
// Obtain a new pending channel ID which is used to track this
// reservation throughout its lifetime.
msg.peer.pendingChannelMtx.Lock()
chanID := msg.peer.nextPendingChannelID
msg.peer.nextPendingChannelID++
msg.peer.pendingChannelMtx.Unlock()
// 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.
f.resMtx.Lock()
if _, ok := f.activeReservations[msg.peer.id]; !ok {
f.activeReservations[msg.peer.id] = make(pendingChannels)
}
f.activeReservations[msg.peer.id][chanID] = &reservationWithCtx{
reservation: reservation,
err: msg.err,
resp: msg.resp,
}
f.resMtx.Unlock()
// Once the reservation has been created, and indexed, queue a funding
// request to the remote peer, kicking off the funding workflow.
contribution := reservation.OurContribution()
deliveryScript, err := txscript.PayToAddrScript(contribution.DeliveryAddress)
if err != nil {
fndgLog.Errorf("Unable to convert address to pkscript: %v", err)
msg.resp <- nil
msg.err <- err
return
}
fndgLog.Infof("Starting funding workflow with for pendingID(%v)", chanID)
// TODO(roasbeef): add FundingRequestFromContribution func
// TODO(roasbeef): need to set fee/kb
fundingReq := lnwire.NewSingleFundingRequest(
chanID,
msg.channelType,
msg.coinType,
0, // TODO(roasbeef): grab from fee estimation model
contribution.FundingAmount,
contribution.CsvDelay,
contribution.CommitKey,
contribution.MultiSigKey,
contribution.RevocationHash,
deliveryScript,
)
msg.peer.queueMsg(fundingReq, nil)
}