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 commitment 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 directly 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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