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83 lines
2.4 KiB
Go
83 lines
2.4 KiB
Go
package liquidity
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import (
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"github.com/btcsuite/btcd/btcutil"
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"github.com/lightninglabs/loop"
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"github.com/lightninglabs/loop/swap"
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"github.com/lightningnetwork/lnd/input"
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"github.com/lightningnetwork/lnd/lnwallet/chainfee"
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"github.com/lightningnetwork/lnd/lnwire"
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"github.com/lightningnetwork/lnd/routing/route"
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)
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// Compile time assertion that loop in suggestions satisfy our interface.
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var _ swapSuggestion = (*loopInSwapSuggestion)(nil)
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type loopInSwapSuggestion struct {
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loop.LoopInRequest
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}
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// amount returns the amount of the swap suggestion.
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func (l *loopInSwapSuggestion) amount() btcutil.Amount {
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return l.Amount
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}
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// fees returns the highest fees that we could pay for the swap suggestion.
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func (l *loopInSwapSuggestion) fees() btcutil.Amount {
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return worstCaseInFees(
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l.MaxMinerFee, l.MaxSwapFee, defaultLoopInSweepFee,
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)
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}
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// channels returns no channels for loop in swap suggestions because we do not
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// restrict loop in swaps by channel id.
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func (l *loopInSwapSuggestion) channels() []lnwire.ShortChannelID {
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return nil
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}
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// peers returns the peer that a loop in swap is restricted to, if it is set.
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func (l *loopInSwapSuggestion) peers(_ map[uint64]route.Vertex) []route.Vertex {
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if l.LastHop == nil {
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return nil
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}
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return []route.Vertex{
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*l.LastHop,
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}
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}
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// worstCaseInFees returns the largest possible fees for a loop in swap.
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func worstCaseInFees(maxMinerFee, swapFee btcutil.Amount,
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sweepEst chainfee.SatPerKWeight) btcutil.Amount {
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failureFee := maxMinerFee + loopInSweepFee(sweepEst)
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successFee := maxMinerFee + swapFee
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if failureFee > successFee {
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return failureFee
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}
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return successFee
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}
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// loopInSweepFee provides an estimated fee for our sweep transaction, based
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// on the fee rate provided. We can calculate our fees for htlcv2 and p2wkh
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// timeout addresses because automated loop ins will be handled entirely by the
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// client, so we know what types will be used.
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func loopInSweepFee(fee chainfee.SatPerKWeight) btcutil.Amount {
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var estimator input.TxWeightEstimator
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// We sweep loop in swaps to wpkh addresses provided by lnd.
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estimator.AddP2WKHOutput()
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// Create a htlcv2, which is what all autoloops will use, so that we
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// can get our maximum timeout witness size.
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htlc := swap.HtlcScriptV2{}
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maxSize := htlc.MaxTimeoutWitnessSize()
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estimator.AddWitnessInput(maxSize)
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weight := int64(estimator.Weight())
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return fee.FeeForWeight(weight)
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}
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