967a9ca7de
In this commit, we add a new witness type to the set of known types. This new type will be used when we need to sweep an HTLC that the remote party has taken to the second level.
129 lines
4.6 KiB
Go
129 lines
4.6 KiB
Go
package lnwallet
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import (
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"fmt"
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"github.com/roasbeef/btcd/txscript"
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"github.com/roasbeef/btcd/wire"
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)
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// WitnessType determines how an output's witness will be generated. The
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// default commitmentTimeLock type will generate a witness that will allow
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// spending of a time-locked transaction enforced by CheckSequenceVerify.
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type WitnessType uint16
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const (
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// CommitmentTimeLock is a witness that allows us to spend the output of
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// a commitment transaction after a relative lock-time lockout.
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CommitmentTimeLock WitnessType = 0
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// CommitmentNoDelay is a witness that allows us to spend a settled
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// no-delay output immediately on a counterparty's commitment
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// transaction.
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CommitmentNoDelay WitnessType = 1
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// CommitmentRevoke is a witness that allows us to sweep the settled
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// output of a malicious counterparty's who broadcasts a revoked
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// commitment transaction.
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CommitmentRevoke WitnessType = 2
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// HtlcOfferedRevoke is a witness that allows us to sweep an HTLC which
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// we offered to the remote party in the case that they broadcast a
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// revoked commitmetn state.
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HtlcOfferedRevoke WitnessType = 3
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// HtlcAcceptedRevoke is a witness that allows us to sweep an HTLC
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// output sent to us in the case that the remote party broadcasts a
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// revoked commitment state.
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HtlcAcceptedRevoke WitnessType = 4
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// HtlcOfferedTimeoutSecondLevel is a witness that allows us to sweep
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// an HTLC output that we extended to a party, but was never fulfilled.
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// This HTLC output isn't directly on the commitment transaction, but
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// is the result of a confirmed second-level HTLC transaction. As a
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// result, we can only spend this after a CSV delay.
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HtlcOfferedTimeoutSecondLevel WitnessType = 5
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// HtlcAcceptedSuccessSecondLevel is a witness that allows us to sweep
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// an HTLC output that was offered to us, and for which we have a
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// payment preimage. This HTLC output isn't diretly on our commitment
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// transaction, but is the result of confirmed second-level HTLC
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// transaction. As a result, we can only spend this after a CSV delay.
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HtlcAcceptedSuccessSecondLevel WitnessType = 6
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// HtlcOfferedRemoteTimeout is a witness that allows us to sweep an
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// HTLC that we offered to the remote party which lies in the
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// commitment transaction of the remote party. We can spend this output
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// after the absolute CLTV timeout of the HTLC as passed.
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HtlcOfferedRemoteTimeout WitnessType = 7
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// HtlcAcceptedRemoteSuccess is a witness that allows us to sweep an
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// HTLC that was offered to us by the remote party. We use this witness
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// in the case that the remote party goes to chain, and we know the
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// pre-image to the HTLC. We can sweep this without any additional
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// timeout.
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HtlcAcceptedRemoteSuccess WitnessType = 8
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// HtlcSecondLevelRevoke is a witness that allows us to sweep an HTLC
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// from the remote party's commitment transaction in the case that the
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// broadcast a revoked commitment, but then also immediately attempt to
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// go to the second level to claim the HTLC.
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HtlcSecondLevelRevoke WitnessType = 9
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)
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// WitnessGenerator represents a function which is able to generate the final
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// witness for a particular public key script. This function acts as an
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// abstraction layer, hiding the details of the underlying script.
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type WitnessGenerator func(tx *wire.MsgTx, hc *txscript.TxSigHashes,
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inputIndex int) ([][]byte, error)
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// GenWitnessFunc will return a WitnessGenerator function that an output
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// uses to generate the witness for a sweep transaction.
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func (wt WitnessType) GenWitnessFunc(signer Signer,
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descriptor *SignDescriptor) WitnessGenerator {
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return func(tx *wire.MsgTx, hc *txscript.TxSigHashes,
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inputIndex int) ([][]byte, error) {
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desc := descriptor
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desc.SigHashes = hc
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desc.InputIndex = inputIndex
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switch wt {
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case CommitmentTimeLock:
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return CommitSpendTimeout(signer, desc, tx)
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case CommitmentNoDelay:
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return CommitSpendNoDelay(signer, desc, tx)
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case CommitmentRevoke:
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return CommitSpendRevoke(signer, desc, tx)
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case HtlcOfferedRevoke:
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return ReceiverHtlcSpendRevoke(signer, desc, tx)
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case HtlcAcceptedRevoke:
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return SenderHtlcSpendRevoke(signer, desc, tx)
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case HtlcOfferedTimeoutSecondLevel:
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return HtlcSecondLevelSpend(signer, desc, tx)
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case HtlcAcceptedSuccessSecondLevel:
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return HtlcSecondLevelSpend(signer, desc, tx)
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case HtlcOfferedRemoteTimeout:
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// We pass in a value of -1 for the timeout, as we
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// expect the caller to have already set the lock time
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// value.
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return receiverHtlcSpendTimeout(signer, desc, tx, -1)
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case HtlcSecondLevelRevoke:
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return htlcSpendRevoke(signer, desc, tx)
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default:
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return nil, fmt.Errorf("unknown witness type: %v", wt)
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}
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}
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}
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