-bytespersigop option to additionally limit sigops in transactions we relay and mine

Author: luke-jr

src/init.cpp

@@ -474,6 +474,7 @@ std::string HelpMessage(HelpMessageMode mode)
     strUsage += HelpMessageGroup(_("Node relay options:"));
     if (showDebug)
         strUsage += HelpMessageOpt("-acceptnonstdtxn", strprintf("Relay and mine \"non-standard\" transactions (%sdefault: %u)", "testnet/regtest only; ", !Params(CBaseChainParams::TESTNET).RequireStandard()));
+    strUsage += HelpMessageOpt("-bytespersigop", strprintf(_("Minimum bytes per sigop in transactions we relay and mine (default: %u)"), DEFAULT_BYTES_PER_SIGOP));
     strUsage += HelpMessageOpt("-datacarrier", strprintf(_("Relay and mine data carrier transactions (default: %u)"), DEFAULT_ACCEPT_DATACARRIER));
     strUsage += HelpMessageOpt("-datacarriersize", strprintf(_("Maximum size of data in data carrier transactions we relay and mine (default: %u)"), MAX_OP_RETURN_RELAY));
 
@@ -937,6 +938,7 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
     fRequireStandard = !GetBoolArg("-acceptnonstdtxn", !Params().RequireStandard());
     if (Params().RequireStandard() && !fRequireStandard)
         return InitError(strprintf("acceptnonstdtxn is not currently supported for %s chain", chainparams.NetworkIDString()));
+    nBytesPerSigOp = GetArg("-bytespersigop", nBytesPerSigOp);
 
 #ifdef ENABLE_WALLET
     if (mapArgs.count("-mintxfee"))

src/main.cpp

@@ -69,6 +69,7 @@ bool fHavePruned = false;
 bool fPruneMode = false;
 bool fIsBareMultisigStd = DEFAULT_PERMIT_BAREMULTISIG;
 bool fRequireStandard = true;
+unsigned int nBytesPerSigOp = DEFAULT_BYTES_PER_SIGOP;
 bool fCheckBlockIndex = false;
 bool fCheckpointsEnabled = DEFAULT_CHECKPOINTS_ENABLED;
 size_t nCoinCacheUsage = 5000 * 300;
@@ -937,16 +938,8 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
         if (fRequireStandard && !AreInputsStandard(tx, view))
             return state.Invalid(false, REJECT_NONSTANDARD, "bad-txns-nonstandard-inputs");
 
-        // Check that the transaction doesn't have an excessive number of
-        // sigops, making it impossible to mine. Since the coinbase transaction
-        // itself can contain sigops MAX_STANDARD_TX_SIGOPS is less than
-        // MAX_BLOCK_SIGOPS; we still consider this an invalid rather than
-        // merely non-standard transaction.
         unsigned int nSigOps = GetLegacySigOpCount(tx);
         nSigOps += GetP2SHSigOpCount(tx, view);
-        if (nSigOps > MAX_STANDARD_TX_SIGOPS)
-            return state.DoS(0, false, REJECT_NONSTANDARD, "bad-txns-too-many-sigops", false,
-                strprintf("%d > %d", nSigOps, MAX_STANDARD_TX_SIGOPS));
 
         CAmount nValueOut = tx.GetValueOut();
         CAmount nFees = nValueIn-nValueOut;
@@ -967,6 +960,15 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
         CTxMemPoolEntry entry(tx, nFees, GetTime(), dPriority, chainActive.Height(), pool.HasNoInputsOf(tx), inChainInputValue, fSpendsCoinbase, nSigOps);
         unsigned int nSize = entry.GetTxSize();
 
+        // Check that the transaction doesn't have an excessive number of
+        // sigops, making it impossible to mine. Since the coinbase transaction
+        // itself can contain sigops MAX_STANDARD_TX_SIGOPS is less than
+        // MAX_BLOCK_SIGOPS; we still consider this an invalid rather than
+        // merely non-standard transaction.
+        if ((nSigOps > MAX_STANDARD_TX_SIGOPS) || (nBytesPerSigOp && nSigOps > nSize / nBytesPerSigOp))
+            return state.DoS(0, false, REJECT_NONSTANDARD, "bad-txns-too-many-sigops", false,
+                strprintf("%d", nSigOps));
+
         // Don't accept it if it can't get into a block
         CAmount txMinFee = GetMinRelayFee(tx, pool, nSize, true);
         if (fLimitFree && nFees < txMinFee)

src/main.h

@@ -92,6 +92,7 @@ static const bool DEFAULT_RELAYPRIORITY = true;
 
 /** Default for -permitbaremultisig */
 static const bool DEFAULT_PERMIT_BAREMULTISIG = true;
+static const unsigned int DEFAULT_BYTES_PER_SIGOP = 20;
 static const bool DEFAULT_CHECKPOINTS_ENABLED = true;
 static const bool DEFAULT_TXINDEX = false;
 static const unsigned int DEFAULT_BANSCORE_THRESHOLD = 100;
@@ -122,6 +123,7 @@ extern int nScriptCheckThreads;
 extern bool fTxIndex;
 extern bool fIsBareMultisigStd;
 extern bool fRequireStandard;
+extern unsigned int nBytesPerSigOp;
 extern bool fCheckBlockIndex;
 extern bool fCheckpointsEnabled;
 extern size_t nCoinCacheUsage;