Use Nethermind as Optimism Sequencer

src/Nethermind/Nethermind.Optimism/Rpc/OptimismEthModuleFactory.cs

@@ -56,7 +56,6 @@ IOptimismSpecHelper opSpecHelper
     private readonly IGasPriceOracle _gasPriceOracle = gasPriceOracle ?? throw new ArgumentNullException(nameof(gasPriceOracle));
     private readonly IEthSyncingInfo _ethSyncingInfo = ethSyncingInfo ?? throw new ArgumentNullException(nameof(ethSyncingInfo));
     private readonly IFeeHistoryOracle _feeHistoryOracle = feeHistoryOracle ?? throw new ArgumentNullException(nameof(feeHistoryOracle));
-    private readonly IJsonRpcClient? _sequencerRpcClient = sequencerRpcClient ?? throw new ArgumentNullException(nameof(sequencerRpcClient));
     private readonly IAccountStateProvider _accountStateProvider = accountStateProvider ?? throw new ArgumentNullException(nameof(accountStateProvider));
     private readonly IEthereumEcdsa _ecdsa = ecdsa ?? throw new ArgumentNullException(nameof(ecdsa));
     private readonly ITxSealer _sealer = sealer ?? throw new ArgumentNullException(nameof(sealer));
@@ -82,7 +81,7 @@ public override IOptimismEthRpcModule Create()
             _feeHistoryOracle,
             secondsPerSlot,
 
-            _sequencerRpcClient,
+            sequencerRpcClient,
             _accountStateProvider,
             _ecdsa,
             _sealer,

src/Nethermind/Nethermind.Optimism/Rpc/OptimismEthRpcModule.cs

@@ -1,7 +1,9 @@
 // SPDX-FileCopyrightText: 2024 Demerzel Solutions Limited
 // SPDX-License-Identifier: LGPL-3.0-only
 
+using System;
 using System.Linq;
+using System.Security;
 using System.Threading.Tasks;
 using Nethermind.Blockchain.Find;
 using Nethermind.Blockchain.Receipts;
@@ -128,16 +130,42 @@ public override async Task<ResultWrapper<Hash256>> eth_sendTransaction(Transacti
 
     public override async Task<ResultWrapper<Hash256>> eth_sendRawTransaction(byte[] transaction)
     {
-        if (_sequencerRpcClient is null)
+        if (_sequencerRpcClient is not null)
         {
-            return ResultWrapper<Hash256>.Fail("No sequencer url in the config");
+            Hash256? result = await _sequencerRpcClient.Post<Hash256>(nameof(eth_sendRawTransaction), transaction);
+            if (result is null)
+            {
+                return ResultWrapper<Hash256>.Fail("Failed to forward transaction");
+            }
+
+            return ResultWrapper<Hash256>.Success(result);
         }
-        Hash256? result = await _sequencerRpcClient.Post<Hash256>(nameof(eth_sendRawTransaction), transaction);
-        if (result is null)
+        else
         {
-            return ResultWrapper<Hash256>.Fail("Failed to forward transaction");
+            try
+            {
+                Transaction tx = Rlp.Decode<Transaction>(transaction, RlpBehaviors.AllowUnsigned | RlpBehaviors.SkipTypedWrapping | RlpBehaviors.InMempoolForm);
+
+                (Hash256 txHash, AcceptTxResult? acceptTxResult) = await _txSender.SendTransaction(tx, TxHandlingOptions.None | TxHandlingOptions.PersistentBroadcast);
+
+                return acceptTxResult.Equals(AcceptTxResult.Accepted)
+                    ? ResultWrapper<Hash256>.Success(txHash)
+                    : ResultWrapper<Hash256>.Fail(acceptTxResult?.ToString() ?? string.Empty, ErrorCodes.TransactionRejected);
+            }
+            catch (SecurityException e)
+            {
+                return ResultWrapper<Hash256>.Fail(e.Message, ErrorCodes.AccountLocked);
+            }
+            catch (RlpException)
+            {
+                return ResultWrapper<Hash256>.Fail("Invalid RLP.", ErrorCodes.TransactionRejected);
+            }
+            catch (Exception e)
+            {
+                if (_logger.IsError) _logger.Error("Failed to send transaction.", e);
+                return ResultWrapper<Hash256>.Fail(e.Message, ErrorCodes.TransactionRejected);
+            }
         }
-        return ResultWrapper<Hash256>.Success(result);
     }
 
     public new ResultWrapper<OptimismReceiptForRpc?> eth_getTransactionReceipt(Hash256 txHash)

src/Nethermind/Nethermind.Optimism/Rpc/RegisterOptimismRpcModules.cs

@@ -52,7 +52,7 @@ protected override void RegisterEthRpcModule(IRpcModuleProvider rpcModuleProvide
 
         if (_config.SequencerUrl is null && _logger.IsWarn)
         {
-            _logger.Warn($"SequencerUrl is not set.");
+            _logger.Warn($"SequencerUrl is not set. Nethermind will behave as a Sequencer");
         }
 
         BasicJsonRpcClient? sequencerJsonRpcClient = _config.SequencerUrl is null