494fcec874
This commit introduces a new sub-system into the daemon whose job it is to vigilantly watch for any potential channel breaches throughout the up-time of the daemon. The logic which was moved from the utxoNursery in a prior commit now resides within the breachArbiter. Upon start-up the breachArbiter will query the database for all active channels, launching a goroutine for each channel in order to be able to take action if a channel breach is detected. The breachArbiter is also responsible for notifying the htlcSwitch about channel breaches in order to black-list the breached linked during any multi-hop forwarding decisions.
136 lines
3.9 KiB
Go
136 lines
3.9 KiB
Go
package lnwallet
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import (
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"github.com/roasbeef/btcd/blockchain"
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)
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const (
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WitnessFactor = blockchain.WitnessScaleFactor
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MaxTransactionWeightPolicy = blockchain.MaxBlockCost / 10
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// The weight(cost), which is different from the !size! (see BIP-141),
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// is calculated as:
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// Weight = 4 * BaseSize + WitnessSize (weight).
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// BaseSize - size of the transaction without witness data (bytes).
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// WitnessSize - witness size (bytes).
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// Weight - the metric for determining the cost of the transaction.
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// P2WSH: 34 bytes
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// - OP_0: 1 byte
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// - OP_DATA: 1 byte (WitnessScriptSHA256 length)
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// - WitnessScriptSHA256: 32 bytes
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P2WSHSize = 1 + 1 + 32
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// P2WPKH: 22 bytes
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// - OP_0: 1 byte
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// - OP_DATA: 1 byte (PublicKeyHASH160 length)
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// - PublicKeyHASH160: 20 bytes
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P2WPKHSize = 1 + 1 + 20
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// MultiSig: 71 bytes
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// - OP_2: 1 byte
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// - OP_DATA: 1 byte (pubKeyAlice length)
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// - pubKeyAlice: 33 bytes
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// - OP_DATA: 1 byte (pubKeyBob length)
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// - pubKeyBob: 33 bytes
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// - OP_2: 1 byte
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// - OP_CHECKMULTISIG: 1 byte
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MultiSigSize = 1 + 1 + 33 + 1 + 33 + 1 + 1
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// Witness: 222 bytes
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// - NumberOfWitnessElements: 1 byte
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// - NilLength: 1 byte
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// - sigAliceLength: 1 byte
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// - sigAlice: 73 bytes
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// - sigBobLength: 1 byte
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// - sigBob: 73 bytes
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// - WitnessScriptLength: 1 byte
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// - WitnessScript (MultiSig)
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WitnessSize = 1 + 1 + 1 + 73 + 1 + 73 + 1 + MultiSigSize
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// FundingInput: 41 bytes
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// - PreviousOutPoint:
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// - Hash: 32 bytes
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// - Index: 4 bytes
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// - OP_DATA: 1 byte (ScriptSigLength)
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// - ScriptSig: 0 bytes
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// - Witness <---- we use "Witness" instead of "ScriptSig" for
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// transaction validation, but "Witness" is stored
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// separately and cost for it size is smaller. So
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// we separate the calculation of ordinary data
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// from witness data.
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// - Sequence: 4 bytes
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FundingInputSize = 32 + 4 + 1 + 4
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// OutputPayingToUs: 43 bytes
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// - Value: 8 bytes
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// - VarInt: 1 byte (PkScript length)
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// - PkScript (P2WSH)
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CommitmentDelayOutput = 8 + 1 + P2WSHSize
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// OutputPayingToThem: 31 bytes
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// - Value: 8 bytes
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// - VarInt: 1 byte (PkScript length)
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// - PkScript (P2WPKH)
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CommitmentKeyHashOutput = 8 + 1 + P2WPKHSize
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// HTLCOutput: 43 bytes
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// - Value: 8 bytes
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// - VarInt: 1 byte (PkScript length)
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// - PkScript (PW2SH)
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HTLCSize = 8 + 1 + P2WSHSize
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// WitnessHeader: 2 bytes
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// - Flag: 1 byte
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// - Marker: 1 byte
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WitnessHeaderSize = 1 + 1
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// CommitmentTransaction: 125 bytes
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// - Version: 4 bytes
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// - WitnessHeader <---- part of the witness data
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// - CountTxIn: 1 byte
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// - TxIn:
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// FundingInput
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// - CountTxOut: 1 byte
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// - TxOut:
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// OutputPayingToThem,
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// OutputPayingToUs,
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// ....HTLCOutputs...
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// - LockTime: 4 bytes
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BaseCommitmentTxSize = 4 + 1 + FundingInputSize + 1 +
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CommitmentDelayOutput + CommitmentKeyHashOutput + 4
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// CommitmentTransactionCost: 500 weight
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BaseCommitmentTxCost = WitnessFactor * BaseCommitmentTxSize
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// WitnessCommitmentTxCost: 224 weight
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WitnessCommitmentTxCost = WitnessHeaderSize + WitnessSize
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// HTLCCost: 172 weight
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HTLCCost = WitnessFactor * HTLCSize
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// MaxHTLCNumber shows as the maximum number HTLCs which can be
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// included in commitment transaction. This numbers was calculated by
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// Rusty Russel in "BOLT #5: Recommendations for On-chain Transaction
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// Handling", based on the fact that we need to sweep all HTLCs within
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// one penalty transaction.
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MaxHTLCNumber = 1253
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)
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// estimateCommitTxCost estimate commitment transaction cost depending on the
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// precalculated cost of base transaction, witness data, which is needed for
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// paying for funding tx, and htlc cost multiplied by their count.
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func estimateCommitTxCost(count int, prediction bool) int64 {
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// Make prediction about the size of commitment transaction with
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// additional HTLC.
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if prediction {
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count++
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}
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htlcCost := int64(count * HTLCCost)
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baseCost := int64(BaseCommitmentTxCost)
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witnessCost := int64(WitnessCommitmentTxCost)
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return htlcCost + baseCost + witnessCost
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}
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