package contractcourt import ( "bytes" "encoding/binary" "fmt" "io" "github.com/btcsuite/btcd/btcec" "github.com/btcsuite/btcd/chaincfg/chainhash" "github.com/btcsuite/btcd/txscript" "github.com/btcsuite/btcd/wire" "github.com/lightningnetwork/lnd/channeldb" "github.com/lightningnetwork/lnd/channeldb/kvdb" "github.com/lightningnetwork/lnd/input" "github.com/lightningnetwork/lnd/lnwallet" ) // ContractResolutions is a wrapper struct around the two forms of resolutions // we may need to carry out once a contract is closing: resolving the // commitment output, and resolving any incoming+outgoing HTLC's still present // in the commitment. type ContractResolutions struct { // CommitHash is the txid of the commitment transaction. CommitHash chainhash.Hash // CommitResolution contains all data required to fully resolve a // commitment output. CommitResolution *lnwallet.CommitOutputResolution // HtlcResolutions contains all data required to fully resolve any // incoming+outgoing HTLC's present within the commitment transaction. HtlcResolutions lnwallet.HtlcResolutions // AnchorResolution contains the data required to sweep the anchor // output. If the channel type doesn't include anchors, the value of // this field will be nil. AnchorResolution *lnwallet.AnchorResolution } // IsEmpty returns true if the set of resolutions is "empty". A resolution is // empty if: our commitment output has been trimmed, and we don't have any // incoming or outgoing HTLC's active. func (c *ContractResolutions) IsEmpty() bool { return c.CommitResolution == nil && len(c.HtlcResolutions.IncomingHTLCs) == 0 && len(c.HtlcResolutions.OutgoingHTLCs) == 0 && c.AnchorResolution == nil } // ArbitratorLog is the primary source of persistent storage for the // ChannelArbitrator. The log stores the current state of the // ChannelArbitrator's internal state machine, any items that are required to // properly make a state transition, and any unresolved contracts. type ArbitratorLog interface { // TODO(roasbeef): document on interface the errors expected to be // returned // CurrentState returns the current state of the ChannelArbitrator. It // takes an optional database transaction, which will be used if it is // non-nil, otherwise the lookup will be done in its own transaction. CurrentState(tx kvdb.RTx) (ArbitratorState, error) // CommitState persists, the current state of the chain attendant. CommitState(ArbitratorState) error // InsertUnresolvedContracts inserts a set of unresolved contracts into // the log. The log will then persistently store each contract until // they've been swapped out, or resolved. It takes a set of report which // should be written to disk if as well if it is non-nil. InsertUnresolvedContracts(reports []*channeldb.ResolverReport, resolvers ...ContractResolver) error // FetchUnresolvedContracts returns all unresolved contracts that have // been previously written to the log. FetchUnresolvedContracts() ([]ContractResolver, error) // SwapContract performs an atomic swap of the old contract for the new // contract. This method is used when after a contract has been fully // resolved, it produces another contract that needs to be resolved. SwapContract(old ContractResolver, new ContractResolver) error // ResolveContract marks a contract as fully resolved. Once a contract // has been fully resolved, it is deleted from persistent storage. ResolveContract(ContractResolver) error // LogContractResolutions stores a complete contract resolution for the // contract under watch. This method will be called once the // ChannelArbitrator either force closes a channel, or detects that the // remote party has broadcast their commitment on chain. LogContractResolutions(*ContractResolutions) error // FetchContractResolutions fetches the set of previously stored // contract resolutions from persistent storage. FetchContractResolutions() (*ContractResolutions, error) // InsertConfirmedCommitSet stores the known set of active HTLCs at the // time channel closure. We'll use this to reconstruct our set of chain // actions anew based on the confirmed and pending commitment state. InsertConfirmedCommitSet(c *CommitSet) error // FetchConfirmedCommitSet fetches the known confirmed active HTLC set // from the database. It takes an optional database transaction, which // will be used if it is non-nil, otherwise the lookup will be done in // its own transaction. FetchConfirmedCommitSet(tx kvdb.RTx) (*CommitSet, error) // FetchChainActions attempts to fetch the set of previously stored // chain actions. We'll use this upon restart to properly advance our // state machine forward. // // NOTE: This method only exists in order to be able to serve nodes had // channels in the process of closing before the CommitSet struct was // introduced. FetchChainActions() (ChainActionMap, error) // WipeHistory is to be called ONLY once *all* contracts have been // fully resolved, and the channel closure if finalized. This method // will delete all on-disk state within the persistent log. WipeHistory() error } // ArbitratorState is an enum that details the current state of the // ChannelArbitrator's state machine. type ArbitratorState uint8 const ( // StateDefault is the default state. In this state, no major actions // need to be executed. StateDefault ArbitratorState = 0 // StateBroadcastCommit is a state that indicates that the attendant // has decided to broadcast the commitment transaction, but hasn't done // so yet. StateBroadcastCommit ArbitratorState = 1 // StateCommitmentBroadcasted is a state that indicates that the // attendant has broadcasted the commitment transaction, and is now // waiting for it to confirm. StateCommitmentBroadcasted ArbitratorState = 6 // StateContractClosed is a state that indicates the contract has // already been "closed", meaning the commitment is confirmed on chain. // At this point, we can now examine our active contracts, in order to // create the proper resolver for each one. StateContractClosed ArbitratorState = 2 // StateWaitingFullResolution is a state that indicates that the // commitment transaction has been confirmed, and the attendant is now // waiting for all unresolved contracts to be fully resolved. StateWaitingFullResolution ArbitratorState = 3 // StateFullyResolved is the final state of the attendant. In this // state, all related contracts have been resolved, and the attendant // can now be garbage collected. StateFullyResolved ArbitratorState = 4 // StateError is the only error state of the resolver. If we enter this // state, then we cannot proceed with manual intervention as a state // transition failed. StateError ArbitratorState = 5 ) // String returns a human readable string describing the ArbitratorState. func (a ArbitratorState) String() string { switch a { case StateDefault: return "StateDefault" case StateBroadcastCommit: return "StateBroadcastCommit" case StateCommitmentBroadcasted: return "StateCommitmentBroadcasted" case StateContractClosed: return "StateContractClosed" case StateWaitingFullResolution: return "StateWaitingFullResolution" case StateFullyResolved: return "StateFullyResolved" case StateError: return "StateError" default: return "unknown state" } } // resolverType is an enum that enumerates the various types of resolvers. When // writing resolvers to disk, we prepend this to the raw bytes stored. This // allows us to properly decode the resolver into the proper type. type resolverType uint8 const ( // resolverTimeout is the type of a resolver that's tasked with // resolving an outgoing HTLC that is very close to timing out. resolverTimeout resolverType = 0 // resolverSuccess is the type of a resolver that's tasked with // resolving an incoming HTLC that we already know the preimage of. resolverSuccess resolverType = 1 // resolverOutgoingContest is the type of a resolver that's tasked with // resolving an outgoing HTLC that hasn't yet timed out. resolverOutgoingContest resolverType = 2 // resolverIncomingContest is the type of a resolver that's tasked with // resolving an incoming HTLC that we don't yet know the preimage to. resolverIncomingContest resolverType = 3 // resolverUnilateralSweep is the type of resolver that's tasked with // sweeping out direct commitment output form the remote party's // commitment transaction. resolverUnilateralSweep resolverType = 4 ) // resolverIDLen is the size of the resolver ID key. This is 36 bytes as we get // 32 bytes from the hash of the prev tx, and 4 bytes for the output index. const resolverIDLen = 36 // resolverID is a key that uniquely identifies a resolver within a particular // chain. For this value we use the full outpoint of the resolver. type resolverID [resolverIDLen]byte // newResolverID returns a resolverID given the outpoint of a contract. func newResolverID(op wire.OutPoint) resolverID { var r resolverID copy(r[:], op.Hash[:]) endian.PutUint32(r[32:], op.Index) return r } // logScope is a key that we use to scope the storage of a ChannelArbitrator // within the global log. We use this key to create a unique bucket within the // database and ensure that we don't have any key collisions. The log's scope // is define as: chainHash || chanPoint, where chanPoint is the chan point of // the original channel. type logScope [32 + 36]byte // newLogScope creates a new logScope key from the passed chainhash and // chanPoint. func newLogScope(chain chainhash.Hash, op wire.OutPoint) (*logScope, error) { var l logScope b := bytes.NewBuffer(l[0:0]) if _, err := b.Write(chain[:]); err != nil { return nil, err } if _, err := b.Write(op.Hash[:]); err != nil { return nil, err } if err := binary.Write(b, endian, op.Index); err != nil { return nil, err } return &l, nil } var ( // stateKey is the key that we use to store the current state of the // arbitrator. stateKey = []byte("state") // contractsBucketKey is the bucket within the logScope that will store // all the active unresolved contracts. contractsBucketKey = []byte("contractkey") // resolutionsKey is the key under the logScope that we'll use to store // the full set of resolutions for a channel. resolutionsKey = []byte("resolutions") // resolutionsSignDetailsKey is the key under the logScope where we // will store input.SignDetails for each HTLC resolution. If this is // not found under the logScope, it means it was written before // SignDetails was introduced, and should be set nil for each HTLC // resolution. resolutionsSignDetailsKey = []byte("resolutions-sign-details") // anchorResolutionKey is the key under the logScope that we'll use to // store the anchor resolution, if any. anchorResolutionKey = []byte("anchor-resolution") // actionsBucketKey is the key under the logScope that we'll use to // store all chain actions once they're determined. actionsBucketKey = []byte("chain-actions") // commitSetKey is the primary key under the logScope that we'll use to // store the confirmed active HTLC sets once we learn that a channel // has closed out on chain. commitSetKey = []byte("commit-set") ) var ( // errScopeBucketNoExist is returned when we can't find the proper // bucket for an arbitrator's scope. errScopeBucketNoExist = fmt.Errorf("scope bucket not found") // errNoContracts is returned when no contracts are found within the // log. errNoContracts = fmt.Errorf("no stored contracts") // errNoResolutions is returned when the log doesn't contain any active // chain resolutions. errNoResolutions = fmt.Errorf("no contract resolutions exist") // errNoActions is retuned when the log doesn't contain any stored // chain actions. errNoActions = fmt.Errorf("no chain actions exist") // errNoCommitSet is return when the log doesn't contained a CommitSet. // This can happen if the channel hasn't closed yet, or a client is // running an older version that didn't yet write this state. errNoCommitSet = fmt.Errorf("no commit set exists") ) // boltArbitratorLog is an implementation of the ArbitratorLog interface backed // by a bolt DB instance. type boltArbitratorLog struct { db kvdb.Backend cfg ChannelArbitratorConfig scopeKey logScope } // newBoltArbitratorLog returns a new instance of the boltArbitratorLog given // an arbitrator config, and the items needed to create its log scope. func newBoltArbitratorLog(db kvdb.Backend, cfg ChannelArbitratorConfig, chainHash chainhash.Hash, chanPoint wire.OutPoint) (*boltArbitratorLog, error) { scope, err := newLogScope(chainHash, chanPoint) if err != nil { return nil, err } return &boltArbitratorLog{ db: db, cfg: cfg, scopeKey: *scope, }, nil } // A compile time check to ensure boltArbitratorLog meets the ArbitratorLog // interface. var _ ArbitratorLog = (*boltArbitratorLog)(nil) func fetchContractReadBucket(tx kvdb.RTx, scopeKey []byte) (kvdb.RBucket, error) { scopeBucket := tx.ReadBucket(scopeKey) if scopeBucket == nil { return nil, errScopeBucketNoExist } contractBucket := scopeBucket.NestedReadBucket(contractsBucketKey) if contractBucket == nil { return nil, errNoContracts } return contractBucket, nil } func fetchContractWriteBucket(tx kvdb.RwTx, scopeKey []byte) (kvdb.RwBucket, error) { scopeBucket, err := tx.CreateTopLevelBucket(scopeKey) if err != nil { return nil, err } contractBucket, err := scopeBucket.CreateBucketIfNotExists( contractsBucketKey, ) if err != nil { return nil, err } return contractBucket, nil } // writeResolver is a helper method that writes a contract resolver and stores // it it within the passed contractBucket using its unique resolutionsKey key. func (b *boltArbitratorLog) writeResolver(contractBucket kvdb.RwBucket, res ContractResolver) error { // Only persist resolvers that are stateful. Stateless resolvers don't // expose a resolver key. resKey := res.ResolverKey() if resKey == nil { return nil } // First, we'll write to the buffer the type of this resolver. Using // this byte, we can later properly deserialize the resolver properly. var ( buf bytes.Buffer rType resolverType ) switch res.(type) { case *htlcTimeoutResolver: rType = resolverTimeout case *htlcSuccessResolver: rType = resolverSuccess case *htlcOutgoingContestResolver: rType = resolverOutgoingContest case *htlcIncomingContestResolver: rType = resolverIncomingContest case *commitSweepResolver: rType = resolverUnilateralSweep } if _, err := buf.Write([]byte{byte(rType)}); err != nil { return err } // With the type of the resolver written, we can then write out the raw // bytes of the resolver itself. if err := res.Encode(&buf); err != nil { return err } return contractBucket.Put(resKey, buf.Bytes()) } // CurrentState returns the current state of the ChannelArbitrator. It takes an // optional database transaction, which will be used if it is non-nil, otherwise // the lookup will be done in its own transaction. // // NOTE: Part of the ContractResolver interface. func (b *boltArbitratorLog) CurrentState(tx kvdb.RTx) (ArbitratorState, error) { var ( s ArbitratorState err error ) if tx != nil { s, err = b.currentState(tx) } else { err = kvdb.View(b.db, func(tx kvdb.RTx) error { s, err = b.currentState(tx) return err }, func() { s = 0 }) } if err != nil && err != errScopeBucketNoExist { return s, err } return s, nil } func (b *boltArbitratorLog) currentState(tx kvdb.RTx) (ArbitratorState, error) { scopeBucket := tx.ReadBucket(b.scopeKey[:]) if scopeBucket == nil { return 0, errScopeBucketNoExist } stateBytes := scopeBucket.Get(stateKey) if stateBytes == nil { return 0, nil } return ArbitratorState(stateBytes[0]), nil } // CommitState persists, the current state of the chain attendant. // // NOTE: Part of the ContractResolver interface. func (b *boltArbitratorLog) CommitState(s ArbitratorState) error { return kvdb.Batch(b.db, func(tx kvdb.RwTx) error { scopeBucket, err := tx.CreateTopLevelBucket(b.scopeKey[:]) if err != nil { return err } return scopeBucket.Put(stateKey[:], []byte{uint8(s)}) }) } // FetchUnresolvedContracts returns all unresolved contracts that have been // previously written to the log. // // NOTE: Part of the ContractResolver interface. func (b *boltArbitratorLog) FetchUnresolvedContracts() ([]ContractResolver, error) { resolverCfg := ResolverConfig{ ChannelArbitratorConfig: b.cfg, Checkpoint: b.checkpointContract, } var contracts []ContractResolver err := kvdb.View(b.db, func(tx kvdb.RTx) error { contractBucket, err := fetchContractReadBucket(tx, b.scopeKey[:]) if err != nil { return err } return contractBucket.ForEach(func(resKey, resBytes []byte) error { if len(resKey) != resolverIDLen { return nil } var res ContractResolver // We'll snip off the first byte of the raw resolver // bytes in order to extract what type of resolver // we're about to encode. resType := resolverType(resBytes[0]) // Then we'll create a reader using the remaining // bytes. resReader := bytes.NewReader(resBytes[1:]) switch resType { case resolverTimeout: res, err = newTimeoutResolverFromReader( resReader, resolverCfg, ) case resolverSuccess: res, err = newSuccessResolverFromReader( resReader, resolverCfg, ) case resolverOutgoingContest: res, err = newOutgoingContestResolverFromReader( resReader, resolverCfg, ) case resolverIncomingContest: res, err = newIncomingContestResolverFromReader( resReader, resolverCfg, ) case resolverUnilateralSweep: res, err = newCommitSweepResolverFromReader( resReader, resolverCfg, ) default: return fmt.Errorf("unknown resolver type: %v", resType) } if err != nil { return err } contracts = append(contracts, res) return nil }) }, func() { contracts = nil }) if err != nil && err != errScopeBucketNoExist && err != errNoContracts { return nil, err } return contracts, nil } // InsertUnresolvedContracts inserts a set of unresolved contracts into the // log. The log will then persistently store each contract until they've been // swapped out, or resolved. // // NOTE: Part of the ContractResolver interface. func (b *boltArbitratorLog) InsertUnresolvedContracts(reports []*channeldb.ResolverReport, resolvers ...ContractResolver) error { return kvdb.Batch(b.db, func(tx kvdb.RwTx) error { contractBucket, err := fetchContractWriteBucket(tx, b.scopeKey[:]) if err != nil { return err } for _, resolver := range resolvers { err = b.writeResolver(contractBucket, resolver) if err != nil { return err } } // Persist any reports that are present. for _, report := range reports { err := b.cfg.PutResolverReport(tx, report) if err != nil { return err } } return nil }) } // SwapContract performs an atomic swap of the old contract for the new // contract. This method is used when after a contract has been fully resolved, // it produces another contract that needs to be resolved. // // NOTE: Part of the ContractResolver interface. func (b *boltArbitratorLog) SwapContract(oldContract, newContract ContractResolver) error { return kvdb.Batch(b.db, func(tx kvdb.RwTx) error { contractBucket, err := fetchContractWriteBucket(tx, b.scopeKey[:]) if err != nil { return err } oldContractkey := oldContract.ResolverKey() if err := contractBucket.Delete(oldContractkey); err != nil { return err } return b.writeResolver(contractBucket, newContract) }) } // ResolveContract marks a contract as fully resolved. Once a contract has been // fully resolved, it is deleted from persistent storage. // // NOTE: Part of the ContractResolver interface. func (b *boltArbitratorLog) ResolveContract(res ContractResolver) error { return kvdb.Batch(b.db, func(tx kvdb.RwTx) error { contractBucket, err := fetchContractWriteBucket(tx, b.scopeKey[:]) if err != nil { return err } resKey := res.ResolverKey() return contractBucket.Delete(resKey) }) } // LogContractResolutions stores a set of chain actions which are derived from // our set of active contracts, and the on-chain state. We'll write this et of // cations when: we decide to go on-chain to resolve a contract, or we detect // that the remote party has gone on-chain. // // NOTE: Part of the ContractResolver interface. func (b *boltArbitratorLog) LogContractResolutions(c *ContractResolutions) error { return kvdb.Batch(b.db, func(tx kvdb.RwTx) error { scopeBucket, err := tx.CreateTopLevelBucket(b.scopeKey[:]) if err != nil { return err } var b bytes.Buffer if _, err := b.Write(c.CommitHash[:]); err != nil { return err } // First, we'll write out the commit output's resolution. if c.CommitResolution == nil { if err := binary.Write(&b, endian, false); err != nil { return err } } else { if err := binary.Write(&b, endian, true); err != nil { return err } err = encodeCommitResolution(&b, c.CommitResolution) if err != nil { return err } } // As we write the HTLC resolutions, we'll serialize the sign // details for each, to store under a new key. var signDetailsBuf bytes.Buffer // With the output for the commitment transaction written, we // can now write out the resolutions for the incoming and // outgoing HTLC's. numIncoming := uint32(len(c.HtlcResolutions.IncomingHTLCs)) if err := binary.Write(&b, endian, numIncoming); err != nil { return err } for _, htlc := range c.HtlcResolutions.IncomingHTLCs { err := encodeIncomingResolution(&b, &htlc) if err != nil { return err } err = encodeSignDetails(&signDetailsBuf, htlc.SignDetails) if err != nil { return err } } numOutgoing := uint32(len(c.HtlcResolutions.OutgoingHTLCs)) if err := binary.Write(&b, endian, numOutgoing); err != nil { return err } for _, htlc := range c.HtlcResolutions.OutgoingHTLCs { err := encodeOutgoingResolution(&b, &htlc) if err != nil { return err } err = encodeSignDetails(&signDetailsBuf, htlc.SignDetails) if err != nil { return err } } // Put the resolutions under the resolutionsKey. err = scopeBucket.Put(resolutionsKey, b.Bytes()) if err != nil { return err } // We'll put the serialized sign details under its own key to // stay backwards compatible. err = scopeBucket.Put( resolutionsSignDetailsKey, signDetailsBuf.Bytes(), ) if err != nil { return err } // Write out the anchor resolution if present. if c.AnchorResolution != nil { var b bytes.Buffer err := encodeAnchorResolution(&b, c.AnchorResolution) if err != nil { return err } err = scopeBucket.Put(anchorResolutionKey, b.Bytes()) if err != nil { return err } } return nil }) } // FetchContractResolutions fetches the set of previously stored contract // resolutions from persistent storage. // // NOTE: Part of the ContractResolver interface. func (b *boltArbitratorLog) FetchContractResolutions() (*ContractResolutions, error) { var c *ContractResolutions err := kvdb.View(b.db, func(tx kvdb.RTx) error { scopeBucket := tx.ReadBucket(b.scopeKey[:]) if scopeBucket == nil { return errScopeBucketNoExist } resolutionBytes := scopeBucket.Get(resolutionsKey) if resolutionBytes == nil { return errNoResolutions } resReader := bytes.NewReader(resolutionBytes) _, err := io.ReadFull(resReader, c.CommitHash[:]) if err != nil { return err } // First, we'll attempt to read out the commit resolution (if // it exists). var haveCommitRes bool err = binary.Read(resReader, endian, &haveCommitRes) if err != nil { return err } if haveCommitRes { c.CommitResolution = &lnwallet.CommitOutputResolution{} err = decodeCommitResolution( resReader, c.CommitResolution, ) if err != nil { return err } } var ( numIncoming uint32 numOutgoing uint32 ) // Next, we'll read out the incoming and outgoing HTLC // resolutions. err = binary.Read(resReader, endian, &numIncoming) if err != nil { return err } c.HtlcResolutions.IncomingHTLCs = make([]lnwallet.IncomingHtlcResolution, numIncoming) for i := uint32(0); i < numIncoming; i++ { err := decodeIncomingResolution( resReader, &c.HtlcResolutions.IncomingHTLCs[i], ) if err != nil { return err } } err = binary.Read(resReader, endian, &numOutgoing) if err != nil { return err } c.HtlcResolutions.OutgoingHTLCs = make([]lnwallet.OutgoingHtlcResolution, numOutgoing) for i := uint32(0); i < numOutgoing; i++ { err := decodeOutgoingResolution( resReader, &c.HtlcResolutions.OutgoingHTLCs[i], ) if err != nil { return err } } // Now we attempt to get the sign details for our HTLC // resolutions. If not present the channel is of a type that // doesn't need them. If present there will be SignDetails // encoded for each HTLC resolution. signDetailsBytes := scopeBucket.Get(resolutionsSignDetailsKey) if signDetailsBytes != nil { r := bytes.NewReader(signDetailsBytes) // They will be encoded in the same order as the // resolutions: firs incoming HTLCs, then outgoing. for i := uint32(0); i < numIncoming; i++ { htlc := &c.HtlcResolutions.IncomingHTLCs[i] htlc.SignDetails, err = decodeSignDetails(r) if err != nil { return err } } for i := uint32(0); i < numOutgoing; i++ { htlc := &c.HtlcResolutions.OutgoingHTLCs[i] htlc.SignDetails, err = decodeSignDetails(r) if err != nil { return err } } } anchorResBytes := scopeBucket.Get(anchorResolutionKey) if anchorResBytes != nil { c.AnchorResolution = &lnwallet.AnchorResolution{} resReader := bytes.NewReader(anchorResBytes) err := decodeAnchorResolution( resReader, c.AnchorResolution, ) if err != nil { return err } } return nil }, func() { c = &ContractResolutions{} }) if err != nil { return nil, err } return c, err } // FetchChainActions attempts to fetch the set of previously stored chain // actions. We'll use this upon restart to properly advance our state machine // forward. // // NOTE: Part of the ContractResolver interface. func (b *boltArbitratorLog) FetchChainActions() (ChainActionMap, error) { var actionsMap ChainActionMap err := kvdb.View(b.db, func(tx kvdb.RTx) error { scopeBucket := tx.ReadBucket(b.scopeKey[:]) if scopeBucket == nil { return errScopeBucketNoExist } actionsBucket := scopeBucket.NestedReadBucket(actionsBucketKey) if actionsBucket == nil { return errNoActions } return actionsBucket.ForEach(func(action, htlcBytes []byte) error { if htlcBytes == nil { return nil } chainAction := ChainAction(action[0]) htlcReader := bytes.NewReader(htlcBytes) htlcs, err := channeldb.DeserializeHtlcs(htlcReader) if err != nil { return err } actionsMap[chainAction] = htlcs return nil }) }, func() { actionsMap = make(ChainActionMap) }) if err != nil { return nil, err } return actionsMap, nil } // InsertConfirmedCommitSet stores the known set of active HTLCs at the time // channel closure. We'll use this to reconstruct our set of chain actions anew // based on the confirmed and pending commitment state. // // NOTE: Part of the ContractResolver interface. func (b *boltArbitratorLog) InsertConfirmedCommitSet(c *CommitSet) error { return kvdb.Batch(b.db, func(tx kvdb.RwTx) error { scopeBucket, err := tx.CreateTopLevelBucket(b.scopeKey[:]) if err != nil { return err } var b bytes.Buffer if err := encodeCommitSet(&b, c); err != nil { return err } return scopeBucket.Put(commitSetKey, b.Bytes()) }) } // FetchConfirmedCommitSet fetches the known confirmed active HTLC set from the // database. It takes an optional database transaction, which will be used if it // is non-nil, otherwise the lookup will be done in its own transaction. // // NOTE: Part of the ContractResolver interface. func (b *boltArbitratorLog) FetchConfirmedCommitSet(tx kvdb.RTx) (*CommitSet, error) { if tx != nil { return b.fetchConfirmedCommitSet(tx) } var c *CommitSet err := kvdb.View(b.db, func(tx kvdb.RTx) error { var err error c, err = b.fetchConfirmedCommitSet(tx) return err }, func() { c = nil }) if err != nil { return nil, err } return c, nil } func (b *boltArbitratorLog) fetchConfirmedCommitSet(tx kvdb.RTx) (*CommitSet, error) { scopeBucket := tx.ReadBucket(b.scopeKey[:]) if scopeBucket == nil { return nil, errScopeBucketNoExist } commitSetBytes := scopeBucket.Get(commitSetKey) if commitSetBytes == nil { return nil, errNoCommitSet } return decodeCommitSet(bytes.NewReader(commitSetBytes)) } // WipeHistory is to be called ONLY once *all* contracts have been fully // resolved, and the channel closure if finalized. This method will delete all // on-disk state within the persistent log. // // NOTE: Part of the ContractResolver interface. func (b *boltArbitratorLog) WipeHistory() error { return kvdb.Update(b.db, func(tx kvdb.RwTx) error { scopeBucket, err := tx.CreateTopLevelBucket(b.scopeKey[:]) if err != nil { return err } // Once we have the main top-level bucket, we'll delete the key // that stores the state of the arbitrator. if err := scopeBucket.Delete(stateKey[:]); err != nil { return err } // Next, we'll delete any lingering contract state within the // contracts bucket by removing the bucket itself. err = scopeBucket.DeleteNestedBucket(contractsBucketKey) if err != nil && err != kvdb.ErrBucketNotFound { return err } // Next, we'll delete storage of any lingering contract // resolutions. if err := scopeBucket.Delete(resolutionsKey); err != nil { return err } err = scopeBucket.Delete(resolutionsSignDetailsKey) if err != nil { return err } // We'll delete any chain actions that are still stored by // removing the enclosing bucket. err = scopeBucket.DeleteNestedBucket(actionsBucketKey) if err != nil && err != kvdb.ErrBucketNotFound { return err } // Finally, we'll delete the enclosing bucket itself. return tx.DeleteTopLevelBucket(b.scopeKey[:]) }, func() {}) } // checkpointContract is a private method that will be fed into // ContractResolver instances to checkpoint their state once they reach // milestones during contract resolution. If the report provided is non-nil, // it should also be recorded. func (b *boltArbitratorLog) checkpointContract(c ContractResolver, reports ...*channeldb.ResolverReport) error { return kvdb.Update(b.db, func(tx kvdb.RwTx) error { contractBucket, err := fetchContractWriteBucket(tx, b.scopeKey[:]) if err != nil { return err } if err := b.writeResolver(contractBucket, c); err != nil { return err } for _, report := range reports { if err := b.cfg.PutResolverReport(tx, report); err != nil { return err } } return nil }, func() {}) } // encodeSignDetails encodes the gived SignDetails struct to the writer. // SignDetails is allowed to be nil, in which we will encode that it is not // present. func encodeSignDetails(w io.Writer, s *input.SignDetails) error { // If we don't have sign details, write false and return. if s == nil { return binary.Write(w, endian, false) } // Otherwise write true, and the contents of the SignDetails. if err := binary.Write(w, endian, true); err != nil { return err } err := input.WriteSignDescriptor(w, &s.SignDesc) if err != nil { return err } err = binary.Write(w, endian, uint32(s.SigHashType)) if err != nil { return err } // Write the DER-encoded signature. b := s.PeerSig.Serialize() if err := wire.WriteVarBytes(w, 0, b); err != nil { return err } return nil } // decodeSignDetails extracts a single SignDetails from the reader. It is // allowed to return nil in case the SignDetails were empty. func decodeSignDetails(r io.Reader) (*input.SignDetails, error) { var present bool if err := binary.Read(r, endian, &present); err != nil { return nil, err } // Simply return nil if the next SignDetails was not present. if !present { return nil, nil } // Otherwise decode the elements of the SignDetails. s := input.SignDetails{} err := input.ReadSignDescriptor(r, &s.SignDesc) if err != nil { return nil, err } var sigHash uint32 err = binary.Read(r, endian, &sigHash) if err != nil { return nil, err } s.SigHashType = txscript.SigHashType(sigHash) // Read DER-encoded signature. rawSig, err := wire.ReadVarBytes(r, 0, 200, "signature") if err != nil { return nil, err } sig, err := btcec.ParseDERSignature(rawSig, btcec.S256()) if err != nil { return nil, err } s.PeerSig = sig return &s, nil } func encodeIncomingResolution(w io.Writer, i *lnwallet.IncomingHtlcResolution) error { if _, err := w.Write(i.Preimage[:]); err != nil { return err } if i.SignedSuccessTx == nil { if err := binary.Write(w, endian, false); err != nil { return err } } else { if err := binary.Write(w, endian, true); err != nil { return err } if err := i.SignedSuccessTx.Serialize(w); err != nil { return err } } if err := binary.Write(w, endian, i.CsvDelay); err != nil { return err } if _, err := w.Write(i.ClaimOutpoint.Hash[:]); err != nil { return err } if err := binary.Write(w, endian, i.ClaimOutpoint.Index); err != nil { return err } err := input.WriteSignDescriptor(w, &i.SweepSignDesc) if err != nil { return err } return nil } func decodeIncomingResolution(r io.Reader, h *lnwallet.IncomingHtlcResolution) error { if _, err := io.ReadFull(r, h.Preimage[:]); err != nil { return err } var txPresent bool if err := binary.Read(r, endian, &txPresent); err != nil { return err } if txPresent { h.SignedSuccessTx = &wire.MsgTx{} if err := h.SignedSuccessTx.Deserialize(r); err != nil { return err } } err := binary.Read(r, endian, &h.CsvDelay) if err != nil { return err } _, err = io.ReadFull(r, h.ClaimOutpoint.Hash[:]) if err != nil { return err } err = binary.Read(r, endian, &h.ClaimOutpoint.Index) if err != nil { return err } return input.ReadSignDescriptor(r, &h.SweepSignDesc) } func encodeOutgoingResolution(w io.Writer, o *lnwallet.OutgoingHtlcResolution) error { if err := binary.Write(w, endian, o.Expiry); err != nil { return err } if o.SignedTimeoutTx == nil { if err := binary.Write(w, endian, false); err != nil { return err } } else { if err := binary.Write(w, endian, true); err != nil { return err } if err := o.SignedTimeoutTx.Serialize(w); err != nil { return err } } if err := binary.Write(w, endian, o.CsvDelay); err != nil { return err } if _, err := w.Write(o.ClaimOutpoint.Hash[:]); err != nil { return err } if err := binary.Write(w, endian, o.ClaimOutpoint.Index); err != nil { return err } return input.WriteSignDescriptor(w, &o.SweepSignDesc) } func decodeOutgoingResolution(r io.Reader, o *lnwallet.OutgoingHtlcResolution) error { err := binary.Read(r, endian, &o.Expiry) if err != nil { return err } var txPresent bool if err := binary.Read(r, endian, &txPresent); err != nil { return err } if txPresent { o.SignedTimeoutTx = &wire.MsgTx{} if err := o.SignedTimeoutTx.Deserialize(r); err != nil { return err } } err = binary.Read(r, endian, &o.CsvDelay) if err != nil { return err } _, err = io.ReadFull(r, o.ClaimOutpoint.Hash[:]) if err != nil { return err } err = binary.Read(r, endian, &o.ClaimOutpoint.Index) if err != nil { return err } return input.ReadSignDescriptor(r, &o.SweepSignDesc) } func encodeCommitResolution(w io.Writer, c *lnwallet.CommitOutputResolution) error { if _, err := w.Write(c.SelfOutPoint.Hash[:]); err != nil { return err } err := binary.Write(w, endian, c.SelfOutPoint.Index) if err != nil { return err } err = input.WriteSignDescriptor(w, &c.SelfOutputSignDesc) if err != nil { return err } return binary.Write(w, endian, c.MaturityDelay) } func decodeCommitResolution(r io.Reader, c *lnwallet.CommitOutputResolution) error { _, err := io.ReadFull(r, c.SelfOutPoint.Hash[:]) if err != nil { return err } err = binary.Read(r, endian, &c.SelfOutPoint.Index) if err != nil { return err } err = input.ReadSignDescriptor(r, &c.SelfOutputSignDesc) if err != nil { return err } return binary.Read(r, endian, &c.MaturityDelay) } func encodeAnchorResolution(w io.Writer, a *lnwallet.AnchorResolution) error { if _, err := w.Write(a.CommitAnchor.Hash[:]); err != nil { return err } err := binary.Write(w, endian, a.CommitAnchor.Index) if err != nil { return err } return input.WriteSignDescriptor(w, &a.AnchorSignDescriptor) } func decodeAnchorResolution(r io.Reader, a *lnwallet.AnchorResolution) error { _, err := io.ReadFull(r, a.CommitAnchor.Hash[:]) if err != nil { return err } err = binary.Read(r, endian, &a.CommitAnchor.Index) if err != nil { return err } return input.ReadSignDescriptor(r, &a.AnchorSignDescriptor) } func encodeHtlcSetKey(w io.Writer, h *HtlcSetKey) error { err := binary.Write(w, endian, h.IsRemote) if err != nil { return err } return binary.Write(w, endian, h.IsPending) } func encodeCommitSet(w io.Writer, c *CommitSet) error { if err := encodeHtlcSetKey(w, c.ConfCommitKey); err != nil { return err } numSets := uint8(len(c.HtlcSets)) if err := binary.Write(w, endian, numSets); err != nil { return err } for htlcSetKey, htlcs := range c.HtlcSets { htlcSetKey := htlcSetKey if err := encodeHtlcSetKey(w, &htlcSetKey); err != nil { return err } if err := channeldb.SerializeHtlcs(w, htlcs...); err != nil { return err } } return nil } func decodeHtlcSetKey(r io.Reader, h *HtlcSetKey) error { err := binary.Read(r, endian, &h.IsRemote) if err != nil { return err } return binary.Read(r, endian, &h.IsPending) } func decodeCommitSet(r io.Reader) (*CommitSet, error) { c := &CommitSet{ ConfCommitKey: &HtlcSetKey{}, HtlcSets: make(map[HtlcSetKey][]channeldb.HTLC), } if err := decodeHtlcSetKey(r, c.ConfCommitKey); err != nil { return nil, err } var numSets uint8 if err := binary.Read(r, endian, &numSets); err != nil { return nil, err } for i := uint8(0); i < numSets; i++ { var htlcSetKey HtlcSetKey if err := decodeHtlcSetKey(r, &htlcSetKey); err != nil { return nil, err } htlcs, err := channeldb.DeserializeHtlcs(r) if err != nil { return nil, err } c.HtlcSets[htlcSetKey] = htlcs } return c, nil }