diff options
Diffstat (limited to 'src/main.cpp')
| -rw-r--r-- | src/main.cpp | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/src/main.cpp b/src/main.cpp index efc70af908..8c60a26b38 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -365,7 +365,24 @@ bool IsStandardTx(const CTransaction& tx, string& reason) return false; } - if (!IsFinalTx(tx)) { + // Treat non-final transactions as non-standard to prevent a specific type + // of double-spend attack, as well as DoS attacks. (if the transaction + // can't be mined, the attacker isn't expending resources broadcasting it) + // Basically we don't want to propagate transactions that can't included in + // the next block. + // + // However, IsFinalTx() is confusing... Without arguments, it uses + // chainActive.Height() to evaluate nLockTime; when a block is accepted, chainActive.Height() + // is set to the value of nHeight in the block. However, when IsFinalTx() + // is called within CBlock::AcceptBlock(), the height of the block *being* + // evaluated is what is used. Thus if we want to know if a transaction can + // be part of the *next* block, we need to call IsFinalTx() with one more + // than chainActive.Height(). + // + // Timestamps on the other hand don't get any special treatment, because we + // can't know what timestamp the next block will have, and there aren't + // timestamp applications where it matters. + if (!IsFinalTx(tx, chainActive.Height() + 1)) { reason = "non-final"; return false; } |