From 88abf70386f18020bb624bca4a4cb7900ce47d0c Mon Sep 17 00:00:00 2001 From: Gavin Andresen Date: Sun, 13 Mar 2011 14:38:07 -0400 Subject: Make sure rate-limiting code is thread-safe --- main.cpp | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) (limited to 'main.cpp') diff --git a/main.cpp b/main.cpp index 5cb1342b91..4214f27ff7 100644 --- a/main.cpp +++ b/main.cpp @@ -739,21 +739,28 @@ bool CTransaction::AcceptToMemoryPool(CTxDB& txdb, bool fCheckInputs, bool* pfMi return error("AcceptToMemoryPool() : not enough fees"); // Continuously rate-limit free transactions + // This mitigates 'penny-flooding' -- sending thousands of free transactions just to + // be annoying or make other's transactions take longer to confirm. if (nFees < CENT) { + static CCriticalSection cs; static double dFreeCount; static int64 nLastTime; int64 nNow = GetTime(); - // Use an exponentially decaying ~10-minute window: - dFreeCount *= pow(1.0 - 1.0/600.0, (double)(nNow - nLastTime)); - nLastTime = nNow; - // -limitfreerelay unit is thousand-bytes-per-minute - // At default rate it would take over a month to fill 1GB - if (dFreeCount > GetArg("-limitfreerelay", 15)*10*1000 && !IsFromMe()) - return error("AcceptToMemoryPool() : free transaction rejected by rate limiter"); - if (fDebug) - printf("Rate limit dFreeCount: %g => %g\n", dFreeCount, dFreeCount+nSize); - dFreeCount += nSize; + + CRITICAL_BLOCK(cs) + { + // Use an exponentially decaying ~10-minute window: + dFreeCount *= pow(1.0 - 1.0/600.0, (double)(nNow - nLastTime)); + nLastTime = nNow; + // -limitfreerelay unit is thousand-bytes-per-minute + // At default rate it would take over a month to fill 1GB + if (dFreeCount > GetArg("-limitfreerelay", 15)*10*1000 && !IsFromMe()) + return error("AcceptToMemoryPool() : free transaction rejected by rate limiter"); + if (fDebug) + printf("Rate limit dFreeCount: %g => %g\n", dFreeCount, dFreeCount+nSize); + dFreeCount += nSize; + } } } -- cgit v1.2.3