package lnwallet import ( "github.com/roasbeef/btcd/blockchain" ) const ( // The weight(weight), which is different from the !size! (see BIP-141), // is calculated as: // Weight = 4 * BaseSize + WitnessSize (weight). // BaseSize - size of the transaction without witness data (bytes). // WitnessSize - witness size (bytes). // Weight - the metric for determining the weight of the transaction. // P2WSHSize 34 bytes // - OP_0: 1 byte // - OP_DATA: 1 byte (WitnessScriptSHA256 length) // - WitnessScriptSHA256: 32 bytes P2WSHSize = 1 + 1 + 32 // P2WKHOutputSize 31 bytes // - value: 8 bytes // - var_int: 1 byte (pkscript_length) // - pkscript (p2wpkh): 22 bytes P2WKHOutputSize = 8 + 1 + 22 // P2WSHOutputSize 43 bytes // - value: 8 bytes // - var_int: 1 byte (pkscript_length) // - pkscript (p2wsh): 34 bytes P2WSHOutputSize = 8 + 1 + 34 // P2WPKHSize 22 bytes // - OP_0: 1 byte // - OP_DATA: 1 byte (PublicKeyHASH160 length) // - PublicKeyHASH160: 20 bytes P2WPKHSize = 1 + 1 + 20 // P2WKHWitnessSize 108 bytes // - OP_DATA: 1 byte (signature length) // - signature // - OP_DATA: 1 byte (pubkey length) // - pubkey P2WKHWitnessSize = 1 + 73 + 1 + 33 // MultiSigSize 71 bytes // - OP_2: 1 byte // - OP_DATA: 1 byte (pubKeyAlice length) // - pubKeyAlice: 33 bytes // - OP_DATA: 1 byte (pubKeyBob length) // - pubKeyBob: 33 bytes // - OP_2: 1 byte // - OP_CHECKMULTISIG: 1 byte MultiSigSize = 1 + 1 + 33 + 1 + 33 + 1 + 1 // WitnessSize 222 bytes // - NumberOfWitnessElements: 1 byte // - NilLength: 1 byte // - sigAliceLength: 1 byte // - sigAlice: 73 bytes // - sigBobLength: 1 byte // - sigBob: 73 bytes // - WitnessScriptLength: 1 byte // - WitnessScript (MultiSig) WitnessSize = 1 + 1 + 1 + 73 + 1 + 73 + 1 + MultiSigSize // InputSize 41 bytes // - PreviousOutPoint: // - Hash: 32 bytes // - Index: 4 bytes // - OP_DATA: 1 byte (ScriptSigLength) // - ScriptSig: 0 bytes // - Witness <---- we use "Witness" instead of "ScriptSig" for // transaction validation, but "Witness" is stored // separately and weight for it size is smaller. So // we separate the calculation of ordinary data // from witness data. // - Sequence: 4 bytes InputSize = 32 + 4 + 1 + 4 // FundingInputSize represents the size of an input to a funding // transaction, and is equivalent to the size of a standard segwit input // as calculated above. FundingInputSize = InputSize // CommitmentDelayOutput 43 bytes // - Value: 8 bytes // - VarInt: 1 byte (PkScript length) // - PkScript (P2WSH) CommitmentDelayOutput = 8 + 1 + P2WSHSize // CommitmentKeyHashOutput 31 bytes // - Value: 8 bytes // - VarInt: 1 byte (PkScript length) // - PkScript (P2WPKH) CommitmentKeyHashOutput = 8 + 1 + P2WPKHSize // HTLCSize 43 bytes // - Value: 8 bytes // - VarInt: 1 byte (PkScript length) // - PkScript (PW2SH) HTLCSize = 8 + 1 + P2WSHSize // WitnessHeaderSize 2 bytes // - Flag: 1 byte // - Marker: 1 byte WitnessHeaderSize = 1 + 1 // BaseSweepTxSize 42 + 41 * num-swept-inputs bytes // - Version: 4 bytes // - WitnessHeader <---- part of the witness data // - CountTxIn: 2 byte // - TxIn: 41 * num-swept-inputs bytes // ....SweptInputs.... // - CountTxOut: 1 byte // - TxOut: 31 bytes // P2WPKHOutput: 31 bytes // - LockTime: 4 bytes BaseSweepTxSize = 4 + 2 + 1 + P2WKHOutputSize + 4 // BaseCommitmentTxSize 125 + 43 * num-htlc-outputs bytes // - Version: 4 bytes // - WitnessHeader <---- part of the witness data // - CountTxIn: 1 byte // - TxIn: 41 bytes // FundingInput // - CountTxOut: 1 byte // - TxOut: 74 + 43 * num-htlc-outputs bytes // OutputPayingToThem, // OutputPayingToUs, // ....HTLCOutputs... // - LockTime: 4 bytes BaseCommitmentTxSize = 4 + 1 + FundingInputSize + 1 + CommitmentDelayOutput + CommitmentKeyHashOutput + 4 // BaseCommitmentTxWeight 500 weight BaseCommitmentTxWeight = blockchain.WitnessScaleFactor * BaseCommitmentTxSize // WitnessCommitmentTxWeight 224 weight WitnessCommitmentTxWeight = WitnessHeaderSize + WitnessSize // HTLCWeight 172 weight HTLCWeight = blockchain.WitnessScaleFactor * HTLCSize // HtlcTimeoutWeight is the weight of the HTLC timeout transaction // which will transition an outgoing HTLC to the delay-and-claim state. HtlcTimeoutWeight = 663 // HtlcSuccessWeight is the weight of the HTLC success transaction // which will transition an incoming HTLC to the delay-and-claim state. HtlcSuccessWeight = 703 // MaxHTLCNumber is the maximum number HTLCs which can be included in a // commitment transaction. This limit was chosen such that, in the case // of a contract breach, the punishment transaction is able to sweep // all the HTLC's yet still remain below the widely used standard // weight limits. MaxHTLCNumber = 966 // ToLocalPenaltyScriptSize 83 bytes // - OP_IF: 1 byte // - OP_DATA: 1 byte (revocationkey length) // - revocationkey: 33 bytes // - OP_CHECKSIG: 1 byte // - OP_ELSE: 1 byte // - OP_DATA: 1 byte (localkey length) // - localkey: 33 bytes // - OP_CHECKSIG_VERIFY: 1 byte // - OP_DATA: 1 byte (delay length) // - delay: 8 bytes // -OP_CHECKSEQUENCEVERIFY: 1 byte // - OP_ENDIF: 1 byte ToLocalPenaltyScriptSize = 1 + 1 + 33 + 1 + 1 + 1 + 33 + 1 + 1 + 8 + 1 + 1 // ToLocalPenaltyWitnessSize 160 bytes // - number_of_witness_elements: 1 byte // - revocation_sig_length: 1 byte // - revocation_sig: 73 bytes // - one_length: 1 byte // - witness_script_length: 1 byte // - witness_script (to_local_script) ToLocalPenaltyWitnessSize = 1 + 1 + 73 + 1 + 1 + ToLocalPenaltyScriptSize // AcceptedHtlcPenaltyScriptSize 139 bytes // - OP_DUP: 1 byte // - OP_HASH160: 1 byte // - OP_DATA: 1 byte (RIPEMD160(SHA256(revocationkey)) length) // - RIPEMD160(SHA256(revocationkey)): 20 bytes // - OP_EQUAL: 1 byte // - OP_IF: 1 byte // - OP_CHECKSIG: 1 byte // - OP_ELSE: 1 byte // - OP_DATA: 1 byte (remotekey length) // - remotekey: 33 bytes // - OP_SWAP: 1 byte // - OP_SIZE: 1 byte // - 32: 1 byte // - OP_EQUAL: 1 byte // - OP_IF: 1 byte // - OP_HASH160: 1 byte // - OP_DATA: 1 byte (RIPEMD160(payment_hash) length) // - RIPEMD160(payment_hash): 20 bytes // - OP_EQUALVERIFY: 1 byte // - 2: 1 byte // - OP_SWAP: 1 byte // - OP_DATA: 1 byte (localkey length) // - localkey: 33 bytes // - 2: 1 byte // - OP_CHECKMULTISIG: 1 byte // - OP_ELSE: 1 byte // - OP_DROP: 1 byte // - OP_DATA: 1 byte (cltv_expiry length) // - cltv_expiry: 4 bytes // - OP_CHECKLOCKTIMEVERIFY: 1 byte // - OP_DROP: 1 byte // - OP_CHECKSIG: 1 byte // - OP_ENDIF: 1 byte // - OP_ENDIF: 1 byte AcceptedHtlcPenaltyScriptSize = 3*1 + 20 + 5*1 + 33 + 7*1 + 20 + 4*1 + 33 + 5*1 + 4 + 5*1 // AcceptedHtlcPenaltyWitnessSize 249 bytes // - number_of_witness_elements: 1 byte // - revocation_sig_length: 1 byte // - revocation_sig: 73 bytes // - revocation_key_length: 1 byte // - revocation_key: 33 bytes // - witness_script_length: 1 byte // - witness_script (accepted_htlc_script) AcceptedHtlcPenaltyWitnessSize = 1 + 1 + 73 + 1 + 33 + 1 + AcceptedHtlcPenaltyScriptSize // OfferedHtlcScriptSize 133 bytes // - OP_DUP: 1 byte // - OP_HASH160: 1 byte // - OP_DATA: 1 byte (RIPEMD160(SHA256(revocationkey)) length) // - RIPEMD160(SHA256(revocationkey)): 20 bytes // - OP_EQUAL: 1 byte // - OP_IF: 1 byte // - OP_CHECKSIG: 1 byte // - OP_ELSE: 1 byte // - OP_DATA: 1 byte (remotekey length) // - remotekey: 33 bytes // - OP_SWAP: 1 byte // - OP_SIZE: 1 byte // - OP_DATA: 1 byte (32 length) // - 32: 1 byte // - OP_EQUAL: 1 byte // - OP_NOTIF: 1 byte // - OP_DROP: 1 byte // - 2: 1 byte // - OP_SWAP: 1 byte // - OP_DATA: 1 byte (localkey length) // - localkey: 33 bytes // - 2: 1 byte // - OP_CHECKMULTISIG: 1 byte // - OP_ELSE: 1 byte // - OP_HASH160: 1 byte // - OP_DATA: 1 byte (RIPEMD160(payment_hash) length) // - RIPEMD160(payment_hash): 20 bytes // - OP_EQUALVERIFY: 1 byte // - OP_CHECKSIG: 1 byte // - OP_ENDIF: 1 byte // - OP_ENDIF: 1 byte OfferedHtlcScriptSize = 3*1 + 20 + 5*1 + 33 + 10*1 + 33 + 5*1 + 20 + 4*1 // OfferedHtlcWitnessSize 243 bytes // - number_of_witness_elements: 1 byte // - revocation_sig_length: 1 byte // - revocation_sig: 73 bytes // - revocation_key_length: 1 byte // - revocation_key: 33 bytes // - witness_script_length: 1 byte // - witness_script (offered_htlc_script) OfferedHtlcWitnessSize = 1 + 1 + 73 + 1 + 33 + 1 + OfferedHtlcScriptSize // OfferedHtlcPenaltyWitnessSize 243 bytes // - number_of_witness_elements: 1 byte // - revocation_sig_length: 1 byte // - revocation_sig: 73 bytes // - revocation_key_length: 1 byte // - revocation_key: 33 bytes // - witness_script_length: 1 byte // - witness_script (offered_htlc_script) OfferedHtlcPenaltyWitnessSize = 1 + 1 + 73 + 1 + 1 + OfferedHtlcScriptSize ) // estimateCommitTxWeight estimate commitment transaction weight depending on // the precalculated weight of base transaction, witness data, which is needed // for paying for funding tx, and htlc weight multiplied by their count. func estimateCommitTxWeight(count int, prediction bool) int64 { // Make prediction about the size of commitment transaction with // additional HTLC. if prediction { count++ } htlcWeight := int64(count * HTLCWeight) baseWeight := int64(BaseCommitmentTxWeight) witnessWeight := int64(WitnessCommitmentTxWeight) return htlcWeight + baseWeight + witnessWeight }