Add support for flashblocks number contract builder tx

README.md

@@ -42,6 +42,22 @@ cargo run -p op-rbuilder --bin op-rbuilder -- node \
     --flashblocks.addr 127.0.0.1 # address to bind the ws that provides flashblocks
 ```
 
+#### Flashblocks Number Contract
+
+To enable builder tranctions to the [flashblocks number contract](https://github.com/Uniswap/flashblocks_number_contract) for contracts to integrate with flashblocks onchain, specify the address in the CLI args:
+
+```bash
+cargo run -p op-rbuilder --bin op-rbuilder -- node \
+    --chain /path/to/chain-config.json \
+    --http \
+    --authrpc.port 9551 \
+    --authrpc.jwtsecret /path/to/jwt.hex \
+    --flashblocks.enabled \
+    --flashblocks.number-contract-address 0xFlashblocksNumberAddress
+```
+
+This will increment the flashblock number before the start of every flashblock and replace the builder tx at the end of the block.
+
 ### Flashtestations 
 
 To run op-rbuilder with flashtestations:

crates/op-rbuilder/src/args/op.rs

@@ -8,6 +8,7 @@ use crate::{
     flashtestations::args::FlashtestationsArgs, gas_limiter::args::GasLimiterArgs,
     tx_signer::Signer,
 };
+use alloy_primitives::Address;
 use anyhow::{Result, anyhow};
 use clap::Parser;
 use reth_optimism_cli::commands::Commands;
@@ -147,6 +148,16 @@ pub struct FlashblocksArgs {
         env = "FLASHBLOCK_LEEWAY_TIME"
     )]
     pub flashblocks_leeway_time: u64,
+
+    /// Flashblocks number contract address
+    ///
+    /// This is the address of the contract that will be used to increment the flashblock number.
+    /// If set a builder tx will be added to the start of every flashblock instead of the regular builder tx.
+    #[arg(
+        long = "flashblocks.number-contract-address",
+        env = "FLASHBLOCK_NUMBER_CONTRACT_ADDRESS"
+    )]
+    pub flashblocks_number_contract_address: Option<Address>,
 }
 
 impl Default for FlashblocksArgs {

crates/op-rbuilder/src/builders/builder_tx.rs

@@ -1,9 +1,12 @@
+use alloy_consensus::TxEip1559;
+use alloy_eips::{Encodable2718, eip7623::TOTAL_COST_FLOOR_PER_TOKEN};
 use alloy_evm::Database;
 use alloy_primitives::{
-    Address,
+    Address, TxKind,
     map::foldhash::{HashSet, HashSetExt},
 };
 use core::fmt::Debug;
+use op_alloy_consensus::OpTypedTransaction;
 use op_revm::OpTransactionError;
 use reth_evm::{ConfigureEvm, Evm, eth::receipt_builder::ReceiptBuilderCtx};
 use reth_node_api::PayloadBuilderError;
@@ -19,7 +22,9 @@ use revm::{
 };
 use tracing::warn;
 
-use crate::{builders::context::OpPayloadBuilderCtx, primitives::reth::ExecutionInfo};
+use crate::{
+    builders::context::OpPayloadBuilderCtx, primitives::reth::ExecutionInfo, tx_signer::Signer,
+};
 
 #[derive(Debug, Clone)]
 pub struct BuilderTransactionCtx {
@@ -148,7 +153,7 @@ pub trait BuilderTransactions<ExtraCtx: Debug + Default = ()>: Debug {
         let state = StateProviderDatabase::new(state_provider.clone());
         let mut simulation_state = State::builder()
             .with_database(state)
-            .with_bundle_prestate(db.bundle_state.clone())
+            .with_cached_prestate(db.cache.clone())
             .with_bundle_update()
             .build();
         let mut evm = ctx
@@ -167,3 +172,100 @@ pub trait BuilderTransactions<ExtraCtx: Debug + Default = ()>: Debug {
         Ok(simulation_state)
     }
 }
+
+#[derive(Debug, Clone)]
+pub struct BuilderTxBase {
+    pub signer: Option<Signer>,
+}
+
+impl BuilderTxBase {
+    pub fn new(signer: Option<Signer>) -> Self {
+        Self { signer }
+    }
+
+    pub fn simulate_builder_tx<ExtraCtx: Debug + Default>(
+        &self,
+        ctx: &OpPayloadBuilderCtx<ExtraCtx>,
+        db: &mut State<impl Database>,
+    ) -> Result<Option<BuilderTransactionCtx>, BuilderTransactionError> {
+        match self.signer {
+            Some(signer) => {
+                let message: Vec<u8> = format!("Block Number: {}", ctx.block_number()).into_bytes();
+                let gas_used = self.estimate_builder_tx_gas(&message);
+                let signed_tx = self.signed_builder_tx(ctx, db, signer, gas_used, message)?;
+                let da_size = op_alloy_flz::tx_estimated_size_fjord_bytes(
+                    signed_tx.encoded_2718().as_slice(),
+                );
+                Ok(Some(BuilderTransactionCtx {
+                    gas_used,
+                    da_size,
+                    signed_tx,
+                }))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn estimate_builder_tx_gas(&self, input: &[u8]) -> u64 {
+        // Count zero and non-zero bytes
+        let (zero_bytes, nonzero_bytes) = input.iter().fold((0, 0), |(zeros, nonzeros), &byte| {
+            if byte == 0 {
+                (zeros + 1, nonzeros)
+            } else {
+                (zeros, nonzeros + 1)
+            }
+        });
+
+        // Calculate gas cost (4 gas per zero byte, 16 gas per non-zero byte)
+        let zero_cost = zero_bytes * 4;
+        let nonzero_cost = nonzero_bytes * 16;
+
+        // Tx gas should be not less than floor gas https://eips.ethereum.org/EIPS/eip-7623
+        let tokens_in_calldata = zero_bytes + nonzero_bytes * 4;
+        let floor_gas = 21_000 + tokens_in_calldata * TOTAL_COST_FLOOR_PER_TOKEN;
+
+        std::cmp::max(zero_cost + nonzero_cost + 21_000, floor_gas)
+    }
+
+    fn signed_builder_tx<ExtraCtx: Debug + Default>(
+        &self,
+        ctx: &OpPayloadBuilderCtx<ExtraCtx>,
+        db: &mut State<impl Database>,
+        signer: Signer,
+        gas_used: u64,
+        message: Vec<u8>,
+    ) -> Result<Recovered<OpTransactionSigned>, BuilderTransactionError> {
+        let nonce = db
+            .load_cache_account(signer.address)
+            .map(|acc| acc.account_info().unwrap_or_default().nonce)
+            .map_err(|_| BuilderTransactionError::AccountLoadFailed(signer.address))?;
+
+        // Create the EIP-1559 transaction
+        let tx = OpTypedTransaction::Eip1559(TxEip1559 {
+            chain_id: ctx.chain_id(),
+            nonce,
+            gas_limit: gas_used,
+            max_fee_per_gas: ctx.base_fee().into(),
+            max_priority_fee_per_gas: 0,
+            to: TxKind::Call(Address::ZERO),
+            // Include the message as part of the transaction data
+            input: message.into(),
+            ..Default::default()
+        });
+        // Sign the transaction
+        let builder_tx = signer
+            .sign_tx(tx)
+            .map_err(BuilderTransactionError::SigningError)?;
+
+        Ok(builder_tx)
+    }
+}
+
+pub fn get_nonce(
+    db: &mut State<impl Database>,
+    address: Address,
+) -> Result<u64, BuilderTransactionError> {
+    db.load_cache_account(address)
+        .map(|acc| acc.account_info().unwrap_or_default().nonce)
+        .map_err(|_| BuilderTransactionError::AccountLoadFailed(address))
+}