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mining: extract witness commitment add into method

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Johan T. Halseth 2021-04-26 13:53:22 +02:00
parent 2d7825cf70
commit f0f4784c1c
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GPG key ID: 15BAADA29DA20D26
1 changed files with 44 additions and 34 deletions
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78
mining/mining.go
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@ -803,40 +803,7 @@ mempoolLoop:
// OP_RETURN output within the coinbase transaction.
var witnessCommitment []byte
if witnessIncluded {
// The witness of the coinbase transaction MUST be exactly 32-bytes
// of all zeroes.
var witnessNonce [blockchain.CoinbaseWitnessDataLen]byte
coinbaseTx.MsgTx().TxIn[0].Witness = wire.TxWitness{witnessNonce[:]}
// Next, obtain the merkle root of a tree which consists of the
// wtxid of all transactions in the block. The coinbase
// transaction will have a special wtxid of all zeroes.
witnessMerkleTree := blockchain.BuildMerkleTreeStore(blockTxns,
true)
witnessMerkleRoot := witnessMerkleTree[len(witnessMerkleTree)-1]
// The preimage to the witness commitment is:
// witnessRoot || coinbaseWitness
var witnessPreimage [64]byte
copy(witnessPreimage[:32], witnessMerkleRoot[:])
copy(witnessPreimage[32:], witnessNonce[:])
// The witness commitment itself is the double-sha256 of the
// witness preimage generated above. With the commitment
// generated, the witness script for the output is: OP_RETURN
// OP_DATA_36 {0xaa21a9ed || witnessCommitment}. The leading
// prefix is referred to as the "witness magic bytes".
witnessCommitment = chainhash.DoubleHashB(witnessPreimage[:])
witnessScript := append(blockchain.WitnessMagicBytes, witnessCommitment...)
// Finally, create the OP_RETURN carrying witness commitment
// output as an additional output within the coinbase.
commitmentOutput := &wire.TxOut{
Value: 0,
PkScript: witnessScript,
}
coinbaseTx.MsgTx().TxOut = append(coinbaseTx.MsgTx().TxOut,
commitmentOutput)
witnessCommitment = AddWitnessCommitment(coinbaseTx, blockTxns)
}
// Calculate the required difficulty for the block. The timestamp
@ -895,6 +862,49 @@ mempoolLoop:
}, nil
}
// AddWitnessCommitment adds the witness commitment as an OP_RETURN outpout
// within the coinbase tx. The raw commitment is returned.
func AddWitnessCommitment(coinbaseTx *btcutil.Tx,
blockTxns []*btcutil.Tx) []byte {
// The witness of the coinbase transaction MUST be exactly 32-bytes
// of all zeroes.
var witnessNonce [blockchain.CoinbaseWitnessDataLen]byte
coinbaseTx.MsgTx().TxIn[0].Witness = wire.TxWitness{witnessNonce[:]}
// Next, obtain the merkle root of a tree which consists of the
// wtxid of all transactions in the block. The coinbase
// transaction will have a special wtxid of all zeroes.
witnessMerkleTree := blockchain.BuildMerkleTreeStore(blockTxns,
true)
witnessMerkleRoot := witnessMerkleTree[len(witnessMerkleTree)-1]
// The preimage to the witness commitment is:
// witnessRoot || coinbaseWitness
var witnessPreimage [64]byte
copy(witnessPreimage[:32], witnessMerkleRoot[:])
copy(witnessPreimage[32:], witnessNonce[:])
// The witness commitment itself is the double-sha256 of the
// witness preimage generated above. With the commitment
// generated, the witness script for the output is: OP_RETURN
// OP_DATA_36 {0xaa21a9ed || witnessCommitment}. The leading
// prefix is referred to as the "witness magic bytes".
witnessCommitment := chainhash.DoubleHashB(witnessPreimage[:])
witnessScript := append(blockchain.WitnessMagicBytes, witnessCommitment...)
// Finally, create the OP_RETURN carrying witness commitment
// output as an additional output within the coinbase.
commitmentOutput := &wire.TxOut{
Value: 0,
PkScript: witnessScript,
}
coinbaseTx.MsgTx().TxOut = append(coinbaseTx.MsgTx().TxOut,
commitmentOutput)
return witnessCommitment
}
// UpdateBlockTime updates the timestamp in the header of the passed block to
// the current time while taking into account the median time of the last
// several blocks to ensure the new time is after that time per the chain