set max bundle tx limit and gas limit

Author: cody-wang-cb

crates/ingress-rpc/src/lib.rs

@@ -193,6 +193,14 @@ pub struct Config {
     #[arg(long, env = "TIPS_INGRESS_BACKRUN_ENABLED", default_value = "false")]
     pub backrun_enabled: bool,
 
+    /// Maximum number of transactions allowed in a backrun bundle (including target tx)
+    #[arg(long, env = "MAX_BACKRUN_TXS", default_value = "5")]
+    pub max_backrun_txs: usize,
+
+    /// Maximum total gas limit for all transactions in a backrun bundle
+    #[arg(long, env = "MAX_BACKRUN_GAS_LIMIT", default_value = "5000000")]
+    pub max_backrun_gas_limit: u64,
+
     /// URL of third-party RPC endpoint to forward raw transactions to (enables forwarding if set)
     #[arg(long, env = "TIPS_INGRESS_RAW_TX_FORWARD_RPC")]
     pub raw_tx_forward_rpc: Option<Url>,

crates/ingress-rpc/src/service.rs

@@ -82,6 +82,8 @@ pub struct IngressService<Q: MessageQueue, M: Mempool> {
     builder_tx: broadcast::Sender<MeterBundleResponse>,
     backrun_enabled: bool,
     builder_backrun_tx: broadcast::Sender<AcceptedBundle>,
+    max_backrun_txs: usize,
+    max_backrun_gas_limit: u64,
 }
 
 impl<Q: MessageQueue, M: Mempool> IngressService<Q, M> {
@@ -127,6 +129,8 @@ impl<Q: MessageQueue, M: Mempool> IngressService<Q, M> {
             builder_tx,
             backrun_enabled: config.backrun_enabled,
             builder_backrun_tx,
+            max_backrun_txs: config.max_backrun_txs,
+            max_backrun_gas_limit: config.max_backrun_gas_limit,
         }
     }
 }
@@ -135,10 +139,6 @@ impl<Q: MessageQueue, M: Mempool> IngressService<Q, M> {
 impl<Q: MessageQueue + 'static, M: Mempool + 'static> IngressApiServer for IngressService<Q, M> {
     async fn send_backrun_bundle(&self, bundle: Bundle) -> RpcResult<BundleHash> {
         if !self.backrun_enabled {
-            info!(
-                message = "Backrun bundle submission is disabled",
-                backrun_enabled = self.backrun_enabled
-            );
             return Err(
                 EthApiError::InvalidParams("Backrun bundle submission is disabled".into())
                     .into_rpc_err(),
@@ -149,16 +149,40 @@ impl<Q: MessageQueue + 'static, M: Mempool + 'static> IngressApiServer for Ingre
         let (accepted_bundle, bundle_hash) =
             self.validate_parse_and_meter_bundle(&bundle, false).await?;
 
-        self.metrics.backrun_bundles_received_total.increment(1);
+        if accepted_bundle.txs.len() < 2 {
+            return Err(EthApiError::InvalidParams(
+                "Backrun bundle must have at least 2 transactions (target + backrun)".into(),
+            )
+            .into_rpc_err());
+        }
 
-        if let Err(e) = self.builder_backrun_tx.send(accepted_bundle.clone()) {
-            warn!(
-                message = "Failed to send backrun bundle to builders",
-                bundle_hash = %bundle_hash,
-                error = %e
-            );
+        if accepted_bundle.txs.len() > self.max_backrun_txs {
+            return Err(EthApiError::InvalidParams(format!(
+                "Backrun bundle exceeds max transaction count: {} > {}",
+                accepted_bundle.txs.len(),
+                self.max_backrun_txs
+            ))
+            .into_rpc_err());
         }
 
+        let total_gas_limit: u64 = accepted_bundle.txs.iter().map(|tx| tx.gas_limit()).sum();
+        if total_gas_limit > self.max_backrun_gas_limit {
+            return Err(EthApiError::InvalidParams(format!(
+                "Backrun bundle exceeds max gas limit: {} > {}",
+                total_gas_limit, self.max_backrun_gas_limit
+            ))
+            .into_rpc_err());
+        }
+
+        self.metrics.backrun_bundles_received_total.increment(1);
+
+        self.builder_backrun_tx
+            .send(accepted_bundle.clone())
+            .map_err(|e| {
+                EthApiError::InvalidParams(format!("Failed to send backrun bundle: {e}"))
+                    .into_rpc_err()
+            })?;
+
         self.send_audit_event(&accepted_bundle, bundle_hash);
 
         self.metrics
@@ -578,6 +602,8 @@ mod tests {
             raw_tx_forward_rpc: None,
             chain_id: 11,
             user_operation_topic: String::new(),
+            max_backrun_txs: 5,
+            max_backrun_gas_limit: 5000000,
         }
     }