Merge pull request #29 from status-im/feat/gas-estimation-at-l2-node

modified RLNProverForwarderValidator to send transaction gas estimation data at l2 node

Author: nadeemb53

README.md

@@ -53,6 +53,14 @@ The Status Network RLN validator system can be configured using various CLI opti
 - **`--plugin-linea-rln-karma-service`**: Karma service endpoint in `host:port` format (default: `localhost:50052`)
 - **`--plugin-linea-rln-deny-list-path`**: Path to the gasless deny list file (default: `/var/lib/besu/gasless-deny-list.txt`)
 
+### Troubleshooting
+- If a 0-gas (gasless) transaction is accepted by the RPC but not included, check the sequencer logs for RLN proof cache timeouts or epoch mismatches and ensure `--plugin-linea-rln-epoch-mode=TEST` is used in local demos.
+- If paid transactions fail for “min gas price” or “upfront cost” locally, ensure L2 genesis has `baseFeePerGas=0` and sequencer `min-gas-price=0` in config.
+- Premium gas transactions (gas > configured threshold) bypass RLN validation by design.
+
+### CI
+- GitHub Actions runs sequencer unit tests (Java 21) with Gradle caching. JNI-dependent RLN native tests are excluded from CI.
+
 ## How to contribute
 
 Contributions are welcome!

besu-plugins/linea-sequencer/sequencer/src/main/java/net/consensys/linea/sequencer/txpoolvalidation/LineaTransactionPoolValidatorFactory.java

@@ -101,7 +101,11 @@ public PluginTransactionPoolValidator createTransactionValidator() {
           new RlnProverForwarderValidator(
               rlnValidatorConf,
               true, // enabled
-              sharedServiceManager.getKarmaServiceClient()));
+              sharedServiceManager.getKarmaServiceClient(),
+              transactionSimulationService,
+              blockchainService,
+              tracerConfiguration,
+              l1L2BridgeConfiguration));
     }
 
     // Conditionally add RLN Validator (for proof verification)

besu-plugins/linea-sequencer/sequencer/src/main/java/net/consensys/linea/sequencer/txpoolvalidation/validators/RlnProverForwarderValidator.java

@@ -20,19 +20,28 @@
 import io.grpc.ManagedChannelBuilder;
 import java.io.Closeable;
 import java.io.IOException;
+import java.math.BigInteger;
 import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import net.consensys.linea.config.LineaRlnValidatorConfiguration;
+import net.consensys.linea.config.LineaTracerConfiguration;
+import net.consensys.linea.plugins.config.LineaL1L2BridgeSharedConfiguration;
 import net.consensys.linea.sequencer.txpoolvalidation.shared.KarmaServiceClient;
 import net.consensys.linea.sequencer.txpoolvalidation.shared.KarmaServiceClient.KarmaInfo;
+import net.consensys.linea.zktracer.LineCountingTracer;
+import net.consensys.linea.zktracer.ZkCounter;
+import net.consensys.linea.zktracer.ZkTracer;
 import net.vac.prover.Address;
 import net.vac.prover.RlnProverGrpc;
 import net.vac.prover.SendTransactionReply;
 import net.vac.prover.SendTransactionRequest;
 import net.vac.prover.U256;
 import net.vac.prover.Wei;
 import org.hyperledger.besu.datatypes.Transaction;
+import org.hyperledger.besu.plugin.data.ProcessableBlockHeader;
+import org.hyperledger.besu.plugin.services.BlockchainService;
+import org.hyperledger.besu.plugin.services.TransactionSimulationService;
 import org.hyperledger.besu.plugin.services.txvalidator.PluginTransactionPoolValidator;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -91,18 +100,44 @@ public class RlnProverForwarderValidator implements PluginTransactionPoolValidat
   // Karma service for gasless validation
   private final KarmaServiceClient karmaServiceClient;
 
+  // Simulation dependencies for estimating gas used
+  private final TransactionSimulationService transactionSimulationService;
+  private final BlockchainService blockchainService;
+  private final LineaTracerConfiguration tracerConfiguration;
+  private final LineaL1L2BridgeSharedConfiguration l1L2BridgeConfiguration;
+
   /**
    * Creates a new RLN Prover Forwarder Validator with default gRPC channel management.
    *
    * @param rlnConfig Configuration for RLN validation including prover service endpoint
    * @param enabled Whether the validator is enabled (should be false in sequencer mode)
    * @param karmaServiceClient Service for checking karma eligibility for gasless transactions
    */
+  public RlnProverForwarderValidator(
+      LineaRlnValidatorConfiguration rlnConfig,
+      boolean enabled,
+      KarmaServiceClient karmaServiceClient,
+      TransactionSimulationService transactionSimulationService,
+      BlockchainService blockchainService,
+      LineaTracerConfiguration tracerConfiguration,
+      LineaL1L2BridgeSharedConfiguration l1L2BridgeSharedConfiguration) {
+    this(
+        rlnConfig,
+        enabled,
+        karmaServiceClient,
+        transactionSimulationService,
+        blockchainService,
+        tracerConfiguration,
+        l1L2BridgeSharedConfiguration,
+        null);
+  }
+
+  /** Backward-compatible constructor used by existing tests. New dependencies default to null. */
   public RlnProverForwarderValidator(
       LineaRlnValidatorConfiguration rlnConfig,
       boolean enabled,
       KarmaServiceClient karmaServiceClient) {
-    this(rlnConfig, enabled, karmaServiceClient, null);
+    this(rlnConfig, enabled, karmaServiceClient, null, null, null, null, null);
   }
 
   /**
@@ -113,7 +148,7 @@ public RlnProverForwarderValidator(
    * @param enabled Whether the validator is enabled (should be false in sequencer mode)
    */
   public RlnProverForwarderValidator(LineaRlnValidatorConfiguration rlnConfig, boolean enabled) {
-    this(rlnConfig, enabled, null, null);
+    this(rlnConfig, enabled, null, null, null, null, null, null);
   }
 
   /**
@@ -132,10 +167,18 @@ public RlnProverForwarderValidator(LineaRlnValidatorConfiguration rlnConfig, boo
       LineaRlnValidatorConfiguration rlnConfig,
       boolean enabled,
       KarmaServiceClient karmaServiceClient,
+      TransactionSimulationService transactionSimulationService,
+      BlockchainService blockchainService,
+      LineaTracerConfiguration tracerConfiguration,
+      LineaL1L2BridgeSharedConfiguration l1L2BridgeSharedConfiguration,
       ManagedChannel providedChannel) {
     this.rlnConfig = rlnConfig;
     this.enabled = enabled;
     this.karmaServiceClient = karmaServiceClient;
+    this.transactionSimulationService = transactionSimulationService;
+    this.blockchainService = blockchainService;
+    this.tracerConfiguration = tracerConfiguration;
+    this.l1L2BridgeConfiguration = l1L2BridgeSharedConfiguration;
 
     if (enabled) {
       if (providedChannel != null) {
@@ -317,6 +360,15 @@ public Optional<String> validateTransaction(
                           .setValue(ByteString.copyFrom(chainId.toByteArray()))
                           .build()));
 
+      // Provide an estimated gas units value. As an initial implementation,
+      // simulate execution to estimate gas used when possible; fallback to tx gas limit.
+      long estimatedGasUsed = estimateGasUsed(transaction);
+      LOG.debug(
+          "Estimated gas used for tx {}: {}",
+          transaction.getHash().toHexString(),
+          estimatedGasUsed);
+      requestBuilder.setEstimatedGasUsed(estimatedGasUsed);
+
       SendTransactionRequest request = requestBuilder.build();
 
       LOG.debug(
@@ -347,6 +399,50 @@ public Optional<String> validateTransaction(
     }
   }
 
+  private LineCountingTracer createLineCountingTracer(
+      final ProcessableBlockHeader pendingBlockHeader, final BigInteger chainId) {
+    var lineCountingTracer =
+        tracerConfiguration != null && tracerConfiguration.isLimitless()
+            ? new ZkCounter(l1L2BridgeConfiguration)
+            : new ZkTracer(
+                net.consensys.linea.zktracer.Fork.LONDON, l1L2BridgeConfiguration, chainId);
+    lineCountingTracer.traceStartConflation(1L);
+    lineCountingTracer.traceStartBlock(pendingBlockHeader, pendingBlockHeader.getCoinbase());
+    return lineCountingTracer;
+  }
+
+  private long estimateGasUsed(final Transaction transaction) {
+    try {
+      // Fast-path: simple ETH transfer with empty calldata
+      if (transaction.getTo().isPresent()
+          && transaction.getPayload().isEmpty()
+          && transaction.getValue().getAsBigInteger().signum() > 0) {
+        return 21_000L;
+      }
+
+      if (transactionSimulationService == null || blockchainService == null) {
+        return transaction.getGasLimit();
+      }
+
+      final var pendingBlockHeader = transactionSimulationService.simulatePendingBlockHeader();
+      final var chainId = blockchainService.getChainId().orElse(BigInteger.ZERO);
+      final var tracer = createLineCountingTracer(pendingBlockHeader, chainId);
+      final var maybeSimulationResults =
+          transactionSimulationService.simulate(
+              transaction, java.util.Optional.empty(), pendingBlockHeader, tracer, false, true);
+
+      if (maybeSimulationResults.isPresent()) {
+        final var sim = maybeSimulationResults.get();
+        if (sim.isSuccessful()) {
+          return sim.result().getEstimateGasUsedByTransaction();
+        }
+      }
+    } catch (final Exception ignored) {
+      // fall through to fallback below
+    }
+    return transaction.getGasLimit();
+  }
+
   /**
    * Closes the gRPC channel and cleans up resources.
    *

besu-plugins/linea-sequencer/sequencer/src/main/proto/rln_proof_service.proto

@@ -135,6 +135,9 @@ message SendTransactionRequest {
   optional Address sender = 2;
   optional U256 chainId = 3;
   bytes transactionHash = 4 [(max_size) = 32];
+  // Estimated gas units the transaction is expected to consume (best-effort)
+  // Backward-compatible addition; receivers may ignore if unsupported.
+  uint64 estimated_gas_used = 5;
 }
 
 message SendTransactionReply {

besu-plugins/linea-sequencer/sequencer/src/test/java/net/consensys/linea/sequencer/txpoolvalidation/validators/RlnProverForwarderValidatorEstimatedGasTest.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright Consensys Software Inc.
+ *
+ * This file is dual-licensed under either the MIT license or Apache License 2.0.
+ * See the LICENSE-MIT and LICENSE-APACHE files in the repository root for details.
+ *
+ * SPDX-License-Identifier: MIT OR Apache-2.0
+ */
+package net.consensys.linea.sequencer.txpoolvalidation.validators;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import io.grpc.ManagedChannel;
+import io.grpc.inprocess.InProcessChannelBuilder;
+import io.grpc.inprocess.InProcessServerBuilder;
+import io.grpc.stub.StreamObserver;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import net.vac.prover.RlnProverGrpc;
+import net.vac.prover.SendTransactionReply;
+import net.vac.prover.SendTransactionRequest;
+import org.apache.tuweni.bytes.Bytes;
+import org.hyperledger.besu.datatypes.Address;
+import org.hyperledger.besu.datatypes.Wei;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class RlnProverForwarderValidatorEstimatedGasTest {
+
+  private io.grpc.Server server;
+  private ManagedChannel channel;
+
+  private volatile SendTransactionRequest capturedRequest;
+
+  @BeforeEach
+  void setUp() throws Exception {
+    final String serverName = InProcessServerBuilder.generateName();
+
+    server =
+        InProcessServerBuilder.forName(serverName)
+            .directExecutor()
+            .addService(
+                new RlnProverGrpc.RlnProverImplBase() {
+                  @Override
+                  public void sendTransaction(
+                      SendTransactionRequest request, StreamObserver<SendTransactionReply> resp) {
+                    capturedRequest = request;
+                    resp.onNext(SendTransactionReply.newBuilder().setResult(true).build());
+                    resp.onCompleted();
+                  }
+                })
+            .build()
+            .start();
+
+    channel = InProcessChannelBuilder.forName(serverName).directExecutor().build();
+  }
+
+  @AfterEach
+  void tearDown() {
+    if (channel != null) {
+      channel.shutdownNow();
+    }
+    if (server != null) {
+      server.shutdownNow();
+    }
+  }
+
+  @Test
+  void forwardsEstimatedGasUsed_21000_forSimpleEthTransfer() throws Exception {
+    final var validator =
+        new RlnProverForwarderValidator(
+            /* rlnConfig */ null,
+            /* enabled */ true,
+            /* karmaServiceClient */ null,
+            /* txSim */ null,
+            /* blockchain */ null,
+            /* tracerConfig */ null,
+            /* l1l2 */ null,
+            /* providedChannel */ channel);
+
+    // Create a simple ETH transfer: to set, empty data, value > 0
+    final org.hyperledger.besu.crypto.SECPSignature fakeSig =
+        org.hyperledger.besu.crypto.SECPSignature.create(
+            new java.math.BigInteger("1"),
+            new java.math.BigInteger("2"),
+            (byte) 0,
+            new java.math.BigInteger("3"));
+
+    final org.hyperledger.besu.ethereum.core.Transaction tx =
+        org.hyperledger.besu.ethereum.core.Transaction.builder()
+            .sender(Address.fromHexString("0x2222222222222222222222222222222222222222"))
+            .to(Address.fromHexString("0x1111111111111111111111111111111111111111"))
+            .gasLimit(21_000)
+            .gasPrice(Wei.of(1))
+            .payload(Bytes.EMPTY)
+            .value(Wei.of(1))
+            .signature(fakeSig)
+            .build();
+
+    final CountDownLatch latch = new CountDownLatch(1);
+    // validateTransaction performs a blocking gRPC call; just invoke and then assert capture
+    final var maybeError =
+        validator.validateTransaction(
+            (org.hyperledger.besu.datatypes.Transaction) tx, /* isLocal */
+            true, /* hasPriority */
+            false);
+    assertThat(maybeError).isEmpty();
+    latch.countDown();
+    latch.await(100, TimeUnit.MILLISECONDS);
+
+    assertThat(capturedRequest).isNotNull();
+    assertThat(capturedRequest.getEstimatedGasUsed()).isEqualTo(21_000L);
+  }
+}

contracts/local-deployments-artifacts/L2MessageServiceAddress.txt

@@ -1 +1 @@
-0x6A461f1BE039c0588A519Ef45C338dD2b388C703
+0x5767aB2Ed64666bFE27e52D4675EDd60Ec7D6EDF

docker/config/l2-node-besu/log4j.xml

@@ -28,6 +28,9 @@
     <Logger name="org.hyperledger.besu.ethereum.api.jsonrpc" level="TRACE" additivity="false">
       <AppenderRef ref="Console"/>
     </Logger>
+    <Logger name="net.consensys.linea.sequencer.txpoolvalidation" level="DEBUG" additivity="false">
+      <AppenderRef ref="Console"/>
+    </Logger>
     <Logger name="io.opentelemetry" level="WARN" additivity="false">
       <AppenderRef ref="Console"/>
     </Logger>