From d640a3ceab4f4372c2a0f738c1286cfde4b41b50 Mon Sep 17 00:00:00 2001 From: Tom Harding Date: Wed, 25 Jun 2014 23:41:44 -0700 Subject: Relay double-spends, subject to anti-DOS Allows network wallets and other clients to see transactions that respend a prevout already spent in an unconfirmed transaction in this node's mempool. Knowledge of an attempted double-spend is of interest to recipients of the first spend. In some cases, it will allow these recipients to withhold goods or services upon being alerted of a double-spend that deprives them of payment. As before, respends are not added to the mempool. Anti-Denial-of-Service-Attack provisions: - Use a bloom filter to relay only one respend per mempool prevout - Rate-limit respend relays to a default of 100 thousand bytes/minute - Define tx2.IsEquivalentTo(tx1): equality when scriptSigs are not considered - Do not relay these equivalent transactions Remove an unused variable declaration in txmempool.cpp. --- src/core.cpp | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'src/core.cpp') diff --git a/src/core.cpp b/src/core.cpp index 6c5ee1c0f..ca2862452 100644 --- a/src/core.cpp +++ b/src/core.cpp @@ -119,6 +119,22 @@ CTransaction& CTransaction::operator=(const CTransaction &tx) { return *this; } +bool CTransaction::IsEquivalentTo(const CTransaction& tx) const +{ + if (nVersion != tx.nVersion || + nLockTime != tx.nLockTime || + vin.size() != tx.vin.size() || + vout != tx.vout) + return false; + for (unsigned int i = 0; i < vin.size(); i++) + { + if (vin[i].nSequence != tx.vin[i].nSequence || + vin[i].prevout != tx.vin[i].prevout) + return false; + } + return true; +} + int64_t CTransaction::GetValueOut() const { int64_t nValueOut = 0; -- cgit v1.2.3