Policy to reject extremely small transactions

A transaction with 1 segwit input and 1 P2WPHK output has non-witness size of 82 bytes. Anything smaller than this have unnecessary malloc overhead and are not relayed/mined.
This commit is contained in:
Johnson Lau 2018-04-27 03:31:36 +08:00
parent 0f8719bb03
commit 7485488e90
2 changed files with 8 additions and 0 deletions

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@ -22,6 +22,8 @@ static const unsigned int DEFAULT_BLOCK_MAX_WEIGHT = MAX_BLOCK_WEIGHT - 4000;
static const unsigned int DEFAULT_BLOCK_MIN_TX_FEE = 1000;
/** The maximum weight for transactions we're willing to relay/mine */
static const unsigned int MAX_STANDARD_TX_WEIGHT = 400000;
/** The minimum non-witness size for transactions we're willing to relay/mine (1 segwit input + 1 P2WPKH output = 82 bytes) */
static const unsigned int MIN_STANDARD_TX_NONWITNESS_SIZE = 82;
/** Maximum number of signature check operations in an IsStandard() P2SH script */
static const unsigned int MAX_P2SH_SIGOPS = 15;
/** The maximum number of sigops we're willing to relay/mine in a single tx */

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@ -582,6 +582,12 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
if (fRequireStandard && !IsStandardTx(tx, reason, witnessEnabled))
return state.DoS(0, false, REJECT_NONSTANDARD, reason);
// Do not work on transactions that are too small.
// A transaction with 1 segwit input and 1 P2WPHK output has non-witness size of 82 bytes.
// Transactions smaller than this are not relayed to reduce unnecessary malloc overhead.
if (::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) < MIN_STANDARD_TX_NONWITNESS_SIZE)
return state.DoS(0, false, REJECT_NONSTANDARD, "tx-size-small");
// Only accept nLockTime-using transactions that can be mined in the next
// block; we don't want our mempool filled up with transactions that can't
// be mined yet.