Add -datacarriernum

Author: ariard

src/init.cpp

@@ -593,6 +593,7 @@ void SetupServerArgs(ArgsManager& argsman)
     argsman.AddArg("-acceptstalefeeestimates", strprintf("Read fee estimates even if they are stale (%sdefault: %u) fee estimates are considered stale if they are %s hours old", "regtest only; ", DEFAULT_ACCEPT_STALE_FEE_ESTIMATES, Ticks<std::chrono::hours>(MAX_FILE_AGE)), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-bytespersigop", strprintf("Equivalent bytes per sigop in transactions for relay and mining (default: %u)", DEFAULT_BYTES_PER_SIGOP), ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
     argsman.AddArg("-datacarrier", strprintf("Relay and mine data carrier transactions (default: %u)", DEFAULT_ACCEPT_DATACARRIER), ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
+    argsman.AddArg("-datacarriernum", strprintf("Relay and mine transacrtions with max %u data carrier outputs", DEFAULT_DATACARRIER_OUTPUTS), ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
     argsman.AddArg("-datacarriersize",
                    strprintf("Relay and mine transactions whose data-carrying raw scriptPubKey "
                              "is of this size or less (default: %u)",

src/kernel/mempool_options.h

@@ -53,6 +53,7 @@ struct MemPoolOptions {
      * If nullopt, any size is nonstandard.
      */
     std::optional<unsigned> max_datacarrier_bytes{DEFAULT_ACCEPT_DATACARRIER ? std::optional{MAX_OP_RETURN_RELAY} : std::nullopt};
+    std::optional<unsigned> max_datacarrier_outputs{DEFAULT_DATACARRIER_OUTPUTS ? std::optional{MAX_DATACARRIER_OUTPUTS} : std::nullopt};
     bool permit_bare_multisig{DEFAULT_PERMIT_BAREMULTISIG};
     bool require_standard{true};
     bool full_rbf{DEFAULT_MEMPOOL_FULL_RBF};

src/node/mempool_args.cpp

@@ -86,6 +86,12 @@ util::Result<void> ApplyArgsManOptions(const ArgsManager& argsman, const CChainP
         mempool_opts.max_datacarrier_bytes = std::nullopt;
     }
 
+    if (argsman.GetBoolArg("-datacarrieroutputs", DEFAULT_DATACARRIER_OUTPUTS)) {
+        mempool_opts.max_datacarrier_outputs = argsman.GetIntArg("-datacarrieroutputs", MAX_DATACARRIER_OUTPUTS);
+    } else {
+        mempool_opts.max_datacarrier_outputs = std::nullopt;
+    }
+
     mempool_opts.require_standard = !argsman.GetBoolArg("-acceptnonstdtxn", DEFAULT_ACCEPT_NON_STD_TXN);
     if (!chainparams.IsTestChain() && !mempool_opts.require_standard) {
         return util::Error{strprintf(Untranslated("acceptnonstdtxn is not currently supported for %s chain"), chainparams.GetChainTypeString())};

src/policy/policy.cpp

@@ -91,7 +91,7 @@ bool IsStandard(const CScript& scriptPubKey, const std::optional<unsigned>& max_
     return true;
 }
 
-bool IsStandardTx(const CTransaction& tx, const std::optional<unsigned>& max_datacarrier_bytes, bool permit_bare_multisig, const CFeeRate& dust_relay_fee, std::string& reason)
+bool IsStandardTx(const CTransaction& tx, const std::optional<unsigned>& max_datacarrier_bytes, const std::optional<unsigned>& max_datacarrier_outputs, bool permit_bare_multisig, const CFeeRate& dust_relay_fee, std::string& reason)
 {
     if (tx.nVersion > TX_MAX_STANDARD_VERSION || tx.nVersion < 1) {
         reason = "version";
@@ -128,8 +128,8 @@ bool IsStandardTx(const CTransaction& tx, const std::optional<unsigned>& max_dat
         }
     }
 
-    unsigned int nDataOut = 0;
     TxoutType whichType;
+    unsigned int nDataOut = 0;
     for (const CTxOut& txout : tx.vout) {
         if (!::IsStandard(txout.scriptPubKey, max_datacarrier_bytes, whichType)) {
             reason = "scriptpubkey";
@@ -147,11 +147,10 @@ bool IsStandardTx(const CTransaction& tx, const std::optional<unsigned>& max_dat
         }
     }
 
-    // only one OP_RETURN txout is permitted
-    //if (nDataOut > 1) {
-    //    reason = "multi-op-return";
-    //    return false;
-    //}
+    if (nDataOut > max_datacarrier_outputs) {
+        reason = "multi-op-return";
+        return false;
+    }
 
     return true;
 }

src/policy/policy.h

@@ -65,11 +65,16 @@ static constexpr unsigned int DEFAULT_DESCENDANT_LIMIT{25};
 static constexpr unsigned int DEFAULT_DESCENDANT_SIZE_LIMIT_KVB{101};
 /** Default for -datacarrier */
 static const bool DEFAULT_ACCEPT_DATACARRIER = true;
+/** Default for -datacarriernum */
+static const bool DEFAULT_DATACARRIER_OUTPUTS = 1;
 /**
  * Default setting for -datacarriersize. 80 bytes of data, +1 for OP_RETURN,
  * +2 for the pushdata opcodes.
  */
 static const unsigned int MAX_OP_RETURN_RELAY = 1000000;
+
+static const unsigned int MAX_DATACARRIER_OUTPUTS = 100;
+
 /**
  * An extra transaction can be added to a package, as long as it only has one
  * ancestor and is no larger than this. Not really any reason to make this
@@ -137,7 +142,7 @@ static constexpr decltype(CTransaction::nVersion) TX_MAX_STANDARD_VERSION{2};
 * Check for standard transaction types
 * @return True if all outputs (scriptPubKeys) use only standard transaction forms
 */
-bool IsStandardTx(const CTransaction& tx, const std::optional<unsigned>& max_datacarrier_bytes, bool permit_bare_multisig, const CFeeRate& dust_relay_fee, std::string& reason);
+bool IsStandardTx(const CTransaction& tx, const std::optional<unsigned>& max_datacarrier_bytes, const std::optional<unsigned>& max_datacarrier_outputs, bool permit_bare_multisig, const CFeeRate& dust_relay_fee, std::string& reason);
 /**
 * Check for standard transaction types
 * @param[in] mapInputs       Map of previous transactions that have outputs we're spending

src/txmempool.cpp

@@ -410,6 +410,7 @@ CTxMemPool::CTxMemPool(const Options& opts)
       m_dust_relay_feerate{opts.dust_relay_feerate},
       m_permit_bare_multisig{opts.permit_bare_multisig},
       m_max_datacarrier_bytes{opts.max_datacarrier_bytes},
+      m_max_datacarrier_outputs{opts.max_datacarrier_outputs},
       m_require_standard{opts.require_standard},
       m_full_rbf{opts.full_rbf},
       m_limits{opts.limits}

src/txmempool.h

@@ -444,6 +444,7 @@ class CTxMemPool
     const CFeeRate m_dust_relay_feerate;
     const bool m_permit_bare_multisig;
     const std::optional<unsigned> m_max_datacarrier_bytes;
+    const std::optional<unsigned> m_max_datacarrier_outputs;
     const bool m_require_standard;
     const bool m_full_rbf;
 

src/validation.cpp

@@ -718,7 +718,7 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
 
     // Rather not work on nonstandard transactions (unless -testnet/-regtest)
     std::string reason;
-    if (m_pool.m_require_standard && !IsStandardTx(tx, m_pool.m_max_datacarrier_bytes, m_pool.m_permit_bare_multisig, m_pool.m_dust_relay_feerate, reason)) {
+    if (m_pool.m_require_standard && !IsStandardTx(tx, m_pool.m_max_datacarrier_bytes, m_pool.m_max_datacarrier_outputs, m_pool.m_permit_bare_multisig, m_pool.m_dust_relay_feerate, reason)) {
         return state.Invalid(TxValidationResult::TX_NOT_STANDARD, reason);
     }