lnwallet: start of HTLC update logic
* moved sorting of transaction outside of createCommitTx also us to add HTLC’s before sorting * On the fence about the proxy object design, will re-visit once we start to implement the p2p code.
This commit is contained in:
Olaoluwa Osuntokun
parent
5a7b98a9e4
commit
1772108544
@ -18,10 +18,12 @@ const (
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MaxPendingPayments = 10
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)
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type PaymentHash [20]byte
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// LightningChannel...
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// TODO(roasbeef): future peer struct should embed this struct
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type LightningChannel struct {
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wallet *LightningWallet
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lnwallet *LightningWallet
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channelEvents *chainntnfs.ChainNotifier
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// TODO(roasbeef): Stores all previous R values + timeouts for each
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@ -34,6 +36,17 @@ type LightningChannel struct {
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stateMtx sync.RWMutex
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channelState channeldb.OpenChannel
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// Payment's which we've requested.
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unfufilledPayments map[PaymentHash]*PaymentRequest
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// Uncleared HTLC's.
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pendingPayments map[PaymentHash]*PaymentDescriptor
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ourPendingCommitTx *wire.MsgTx
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theirPendingCommitTx *wire.MsgTx
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fundingTxIn *wire.TxIn
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// TODO(roasbeef): create and embed 'Service' interface w/ below?
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started int32
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shutdown int32
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@ -46,81 +59,254 @@ type LightningChannel struct {
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func newLightningChannel(wallet *LightningWallet, events *chainntnfs.ChainNotifier,
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chanDB *channeldb.DB, state channeldb.OpenChannel) (*LightningChannel, error) {
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return &LightningChannel{
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wallet: wallet,
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lc := &LightningChannel{
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lnwallet: wallet,
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channelEvents: events,
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channelDB: chanDB,
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channelState: state,
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}, nil
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}
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fundingTxId := state.FundingTx.TxSha()
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fundingPkScript, err := scriptHashPkScript(state.FundingRedeemScript)
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if err != nil {
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return nil, err
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}
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_, multiSigIndex := findScriptOutputIndex(state.FundingTx, fundingPkScript)
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lc.fundingTxIn = wire.NewTxIn(wire.NewOutPoint(&fundingTxId, multiSigIndex), nil)
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return lc, nil
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}
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// PaymentDescriptor...
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type PaymentDescriptor struct {
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RHash [20]byte
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OurRevocation [20]byte // TODO(roasbeef): don't need these?
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TheirRevocation [20]byte
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Timeout uint32
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Value btcutil.Amount
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PayToUs bool
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lnchannel *LightningChannel
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}
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// AddHTLC...
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func (lc *LightningChannel) AddHTLC() {
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// 1. request R_Hash from receiver (only if single hop, would be out of band)
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// 2. propose HTLC
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// * timeout
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// * value
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// * r_hash
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// * next revocation hash
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// Can build our new commitment tx at this point
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// 3. they accept
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// * their next revocation hash
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// * their sig for our new commitment tx (verify correctness)
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// 4. we give sigs
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// * our sigs for their new commitment tx
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// * the pre-image to our old commitment tx
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// 5. they complete
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// * the pre-image to their old commitment tx (verify is part of their chain, is pre-image)
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func (lc *LightningChannel) AddHTLC(timeout uint32, value btcutil.Amount,
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rHash, revocation PaymentHash, payToUs bool) (*PaymentDescriptor, []byte, error) {
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lc.stateMtx.Lock()
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defer lc.stateMtx.Unlock()
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paymentDetails := &PaymentDescriptor{
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RHash: rHash,
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TheirRevocation: revocation,
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Timeout: timeout,
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Value: value,
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PayToUs: payToUs,
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lnchannel: lc,
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}
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lc.channelState.TheirCurrentRevocation = revocation
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// Get next revocation hash, updating the number of updates in the
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// channel as a result.
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updateNum := lc.channelState.NumUpdates + 1
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nextPreimage, err := lc.channelState.OurShaChain.GetHash(updateNum)
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if err != nil {
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return nil, nil, err
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}
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copy(paymentDetails.OurRevocation[:], btcutil.Hash160(nextPreimage[:]))
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lc.channelState.NumUpdates = updateNum
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// Re-calculate the amount of cleared funds for each side.
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var amountToUs, amountToThem btcutil.Amount
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if payToUs {
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amountToUs = lc.channelState.OurBalance + value
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amountToThem = lc.channelState.TheirBalance - value
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} else {
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amountToUs = lc.channelState.OurBalance - value
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amountToThem = lc.channelState.TheirBalance + value
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}
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// Re-create copies of the current commitment transactions to be updated.
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ourNewCommitTx, err := createCommitTx(lc.fundingTxIn,
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lc.channelState.OurCommitKey.PubKey(), lc.channelState.TheirCommitKey,
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paymentDetails.OurRevocation[:], lc.channelState.CsvDelay,
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amountToUs, amountToThem)
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if err != nil {
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return nil, nil, err
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}
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theirNewCommitTx, err := createCommitTx(lc.fundingTxIn,
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lc.channelState.TheirCommitKey, lc.channelState.OurCommitKey.PubKey(),
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paymentDetails.TheirRevocation[:], lc.channelState.CsvDelay,
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amountToThem, amountToUs)
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if err != nil {
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return nil, nil, err
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}
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// First, re-add all the old HTLCs.
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for _, paymentDesc := range lc.pendingPayments {
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if err := lc.addHTLC(ourNewCommitTx, theirNewCommitTx, paymentDesc); err != nil {
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return nil, nil, err
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}
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}
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// Then add this new HTLC.
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if err := lc.addHTLC(ourNewCommitTx, theirNewCommitTx, paymentDetails); err != nil {
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return nil, nil, err
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}
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lc.pendingPayments[rHash] = paymentDetails // TODO(roasbeef): check for dups?
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// Sort both transactions according to the agreed upon cannonical
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// ordering. This lets us skip sending the entire transaction over,
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// instead we'll just send signatures.
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txsort.InPlaceSort(ourNewCommitTx)
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txsort.InPlaceSort(theirNewCommitTx)
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// TODO(roasbeef): locktimes/sequence set
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// Sign their version of the commitment transaction.
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sigTheirCommit, err := txscript.RawTxInSignature(theirNewCommitTx, 0,
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lc.channelState.FundingRedeemScript, txscript.SigHashAll,
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lc.channelState.MultiSigKey)
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if err != nil {
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return nil, nil, err
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}
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// TODO(roasbeef): write checkpoint here...
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return paymentDetails, sigTheirCommit, nil
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}
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// addHTLC...
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// NOTE: This MUST be called with stateMtx held.
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func (lc *LightningChannel) addHTLC(ourCommitTx, theirCommitTx *wire.MsgTx,
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paymentDesc *PaymentDescriptor) error {
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// If the HTLC is going to us, then we're the sender, otherwise they
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// are.
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var senderKey, receiverKey *btcec.PublicKey
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var senderRevocation, receiverRevocation []byte
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if paymentDesc.PayToUs {
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receiverKey = lc.channelState.OurCommitKey.PubKey()
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receiverRevocation = paymentDesc.OurRevocation[:]
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senderKey = lc.channelState.TheirCommitKey
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senderRevocation = paymentDesc.TheirRevocation[:]
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} else {
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senderKey = lc.channelState.OurCommitKey.PubKey()
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senderRevocation = paymentDesc.OurRevocation[:]
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receiverKey = lc.channelState.TheirCommitKey
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receiverRevocation = paymentDesc.TheirRevocation[:]
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}
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// Generate the proper redeem scripts for the HTLC output for both the
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// sender and the receiver.
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timeout := paymentDesc.Timeout
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rHash := paymentDesc.RHash
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delay := lc.channelState.CsvDelay
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senderPKScript, err := senderHTLCScript(timeout, delay, senderKey,
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receiverKey, senderRevocation[:], rHash[:])
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if err != nil {
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return nil
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}
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receiverPKScript, err := receiverHTLCScript(timeout, delay, senderKey,
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receiverKey, receiverRevocation[:], rHash[:])
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if err != nil {
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return nil
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}
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// Now that we have the redeem scripts, create the P2SH public key
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// script for each.
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senderP2SH, err := scriptHashPkScript(senderPKScript)
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if err != nil {
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return nil
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}
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receiverP2SH, err := scriptHashPkScript(receiverPKScript)
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if err != nil {
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return nil
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}
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// Add the new HTLC outputs to the respective commitment transactions.
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amountPending := int64(paymentDesc.Value)
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if paymentDesc.PayToUs {
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ourCommitTx.AddTxOut(wire.NewTxOut(amountPending, receiverP2SH))
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theirCommitTx.AddTxOut(wire.NewTxOut(amountPending, senderP2SH))
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} else {
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ourCommitTx.AddTxOut(wire.NewTxOut(amountPending, senderP2SH))
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theirCommitTx.AddTxOut(wire.NewTxOut(amountPending, receiverP2SH))
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}
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return nil
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}
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// SettleHTLC...
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func (lc *LightningChannel) SettleHTLC() {
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// R-VALUE, NEW REVOKE HASH
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// accept, sig
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func (lc *LightningChannel) SettleHTLC(rValue []byte) error {
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return nil
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}
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// CancelHTLC...
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func (lc *LightningChannel) CancelHTLC() error {
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return nil
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}
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// OurBalance...
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func (lc *LightningChannel) OurBalance() btcutil.Amount {
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return 0
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lc.stateMtx.RLock()
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defer lc.stateMtx.RUnlock()
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return lc.channelState.OurBalance
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}
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// TheirBalance...
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func (lc *LightningChannel) TheirBalance() btcutil.Amount {
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return 0
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lc.stateMtx.RLock()
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defer lc.stateMtx.RUnlock()
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return lc.channelState.TheirBalance
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}
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// CurrentCommitTx...
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func (lc *LightningChannel) CurrentCommitTx() *btcutil.Tx {
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// ForceClose...
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func (lc *LightningChannel) ForceClose() error {
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return nil
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}
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// SignTheirCommitTx...
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func (lc *LightningChannel) SignTheirCommitTx(commitTx *btcutil.Tx) error {
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// RequestPayment...
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func (lc *LightningChannel) RequestPayment(amount btcutil.Amount) error {
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// Validate amount
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return nil
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}
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// AddTheirSig...
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func (lc *LightningChannel) AddTheirSig(sig []byte) error {
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return nil
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}
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// VerifyCommitmentUpdate...
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func (lc *LightningChannel) VerifyCommitmentUpdate() error {
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return nil
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// PaymentRequest...
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// TODO(roasbeef): serialization (bip 70, QR code, etc)
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// * routing handled by upper layer
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type PaymentRequest struct {
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PaymentPreImage [20]byte
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Value btcutil.Amount
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}
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// createCommitTx...
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func createCommitTx(fundingOutput *wire.TxIn, ourKey, theirKey *btcec.PublicKey,
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revokeHash [wire.HashSize]byte, csvTimeout uint32, channelAmt btcutil.Amount) (*wire.MsgTx, error) {
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// TODO(roasbeef): fix inconsistency of 32 vs 20 byte revocation hashes everywhere...
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func createCommitTx(fundingOutput *wire.TxIn, selfKey, theirKey *btcec.PublicKey,
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revokeHash []byte, csvTimeout uint32, amountToSelf,
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amountToThem btcutil.Amount) (*wire.MsgTx, error) {
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// First, we create the script paying to us. This script is spendable
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// under two conditions: either the 'csvTimeout' has passed and we can
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// redeem our funds, or they have the pre-image to 'revokeHash'.
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scriptToUs := txscript.NewScriptBuilder()
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// If the pre-image for the revocation hash is presented, then allow a
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// spend provided the proper signature.
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scriptToUs.AddOp(txscript.OP_HASH160)
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scriptToUs.AddData(revokeHash[:])
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scriptToUs.AddOp(txscript.OP_EQUAL)
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scriptToUs.AddOp(txscript.OP_IF)
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scriptToUs.AddData(theirKey.SerializeCompressed())
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scriptToUs.AddOp(txscript.OP_ELSE)
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// Otherwise, we can re-claim our funds after a CSV delay of
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// 'csvTimeout' timeout blocks, and a valid signature.
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scriptToUs.AddInt64(int64(csvTimeout))
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scriptToUs.AddOp(txscript.OP_NOP3) // CSV
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scriptToUs.AddOp(txscript.OP_DROP)
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scriptToUs.AddData(ourKey.SerializeCompressed())
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scriptToUs.AddOp(txscript.OP_ENDIF)
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scriptToUs.AddOp(txscript.OP_CHECKSIG)
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// TODO(roasbeef): store
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ourRedeemScript, err := scriptToUs.Script()
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// First, we create the script for the delayed "pay-to-self" output.
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ourRedeemScript, err := commitScriptToSelf(csvTimeout, selfKey, theirKey,
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revokeHash)
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if err != nil {
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return nil, err
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}
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@ -130,15 +316,9 @@ func createCommitTx(fundingOutput *wire.TxIn, ourKey, theirKey *btcec.PublicKey,
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}
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// Next, we create the script paying to them. This is just a regular
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// P2PKH-ike output. However, we instead use P2SH.
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scriptToThem := txscript.NewScriptBuilder()
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scriptToThem.AddOp(txscript.OP_DUP)
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scriptToThem.AddOp(txscript.OP_HASH160)
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scriptToThem.AddData(btcutil.Hash160(theirKey.SerializeCompressed()))
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scriptToThem.AddOp(txscript.OP_EQUALVERIFY)
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scriptToThem.AddOp(txscript.OP_CHECKSIG)
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theirRedeemScript, err := scriptToThem.Script()
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// P2PKH-like output, without any added CSV delay. However, we instead
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// use P2SH.
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theirRedeemScript, err := commitScriptUnencumbered(theirKey)
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if err != nil {
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return nil, err
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}
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@ -154,13 +334,9 @@ func createCommitTx(fundingOutput *wire.TxIn, ourKey, theirKey *btcec.PublicKey,
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// TODO(roasbeef): we default to blocks, make configurable as part of
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// channel reservation.
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commitTx.TxIn[0].Sequence = lockTimeToSequence(false, csvTimeout)
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commitTx.AddTxOut(wire.NewTxOut(int64(channelAmt), payToUsScriptHash))
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commitTx.AddTxOut(wire.NewTxOut(int64(channelAmt), payToThemScriptHash))
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commitTx.AddTxOut(wire.NewTxOut(int64(amountToSelf), payToUsScriptHash))
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commitTx.AddTxOut(wire.NewTxOut(int64(amountToThem), payToThemScriptHash))
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// Sort the transaction according to the agreed upon cannonical
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// ordering. This lets us skip sending the entire transaction over,
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// instead we'll just send signatures.
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txsort.InPlaceSort(commitTx)
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return commitTx, nil
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}
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@ -788,19 +788,26 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
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ourCommitKey := ourContribution.CommitKey
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theirCommitKey := theirContribution.CommitKey
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ourCommitTx, err := createCommitTx(fundingTxIn, ourCommitKey, theirCommitKey,
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ourCurrentRevokeHash, theirContribution.CsvDelay, initialBalance)
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ourCurrentRevokeHash[:], theirContribution.CsvDelay,
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initialBalance, initialBalance)
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if err != nil {
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req.err <- err
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return
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}
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theirCommitTx, err := createCommitTx(fundingTxIn, theirCommitKey, ourCommitKey,
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theirContribution.RevocationHash, theirContribution.CsvDelay, initialBalance)
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theirContribution.RevocationHash[:], theirContribution.CsvDelay,
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initialBalance, initialBalance)
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if err != nil {
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req.err <- err
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return
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}
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// Sort both transactions according to the agreed upon cannonical
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// ordering. This lets us skip sending the entire transaction over,
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// instead we'll just send signatures.
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txsort.InPlaceSort(ourCommitTx)
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txsort.InPlaceSort(theirCommitTx)
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// Record newly available information witin the open channel state.
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pendingReservation.partialState.CsvDelay = theirContribution.CsvDelay
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pendingReservation.partialState.TheirDeliveryAddress = theirContribution.DeliveryAddress
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