From beb8fac91ba49c8c71654faae3a8ff0f5c7c1db3 Mon Sep 17 00:00:00 2001
From: Varun Doshi <doshivarun202@gmail.com>
Date: Sat, 5 Jul 2025 09:58:10 +0530
Subject: [PATCH] feat: add v5 flashbots relay block validation api for Fusaka
 (#17179)

Co-authored-by: Matthias Seitz <matthias.seitz@outlook.de>
---
 crates/rpc/rpc-api/src/validation.rs |  8 ++++
 crates/rpc/rpc/Cargo.toml            |  2 +-
 crates/rpc/rpc/src/validation.rs     | 70 +++++++++++++++++++++++++++-
 3 files changed, 77 insertions(+), 3 deletions(-)

diff --git a/crates/rpc/rpc-api/src/validation.rs b/crates/rpc/rpc-api/src/validation.rs
index 5e4f2e2614..9ff47b5eaf 100644
--- a/crates/rpc/rpc-api/src/validation.rs
+++ b/crates/rpc/rpc-api/src/validation.rs
@@ -3,6 +3,7 @@
 use alloy_rpc_types_beacon::relay::{
     BuilderBlockValidationRequest, BuilderBlockValidationRequestV2,
     BuilderBlockValidationRequestV3, BuilderBlockValidationRequestV4,
+    BuilderBlockValidationRequestV5,
 };
 use jsonrpsee::proc_macros::rpc;
 
@@ -37,4 +38,11 @@ pub trait BlockSubmissionValidationApi {
         &self,
         request: BuilderBlockValidationRequestV4,
     ) -> jsonrpsee::core::RpcResult<()>;
+
+    /// A Request to validate a block submission.
+    #[method(name = "validateBuilderSubmissionV5")]
+    async fn validate_builder_submission_v5(
+        &self,
+        request: BuilderBlockValidationRequestV5,
+    ) -> jsonrpsee::core::RpcResult<()>;
 }
diff --git a/crates/rpc/rpc/Cargo.toml b/crates/rpc/rpc/Cargo.toml
index 2f41caa548..389502a2c7 100644
--- a/crates/rpc/rpc/Cargo.toml
+++ b/crates/rpc/rpc/Cargo.toml
@@ -60,7 +60,7 @@ alloy-rpc-types-trace.workspace = true
 alloy-rpc-types-mev.workspace = true
 alloy-rpc-types-txpool.workspace = true
 alloy-rpc-types-admin.workspace = true
-alloy-rpc-types-engine.workspace = true
+alloy-rpc-types-engine = { workspace = true, features = ["kzg"] }
 alloy-serde.workspace = true
 revm = { workspace = true, features = ["optional_block_gas_limit", "optional_eip3607", "optional_no_base_fee"] }
 revm-primitives = { workspace = true, features = ["serde"] }
diff --git a/crates/rpc/rpc/src/validation.rs b/crates/rpc/rpc/src/validation.rs
index e2d5a553d5..6ec2a1b720 100644
--- a/crates/rpc/rpc/src/validation.rs
+++ b/crates/rpc/rpc/src/validation.rs
@@ -5,10 +5,11 @@ use alloy_eips::{eip4844::kzg_to_versioned_hash, eip7685::RequestsOrHash};
 use alloy_rpc_types_beacon::relay::{
     BidTrace, BuilderBlockValidationRequest, BuilderBlockValidationRequestV2,
     BuilderBlockValidationRequestV3, BuilderBlockValidationRequestV4,
+    BuilderBlockValidationRequestV5,
 };
 use alloy_rpc_types_engine::{
-    BlobsBundleV1, CancunPayloadFields, ExecutionData, ExecutionPayload, ExecutionPayloadSidecar,
-    PraguePayloadFields,
+    BlobsBundleV1, BlobsBundleV2, CancunPayloadFields, ExecutionData, ExecutionPayload,
+    ExecutionPayloadSidecar, PraguePayloadFields,
 };
 use async_trait::async_trait;
 use core::fmt;
@@ -365,6 +366,24 @@ where
 
         Ok(versioned_hashes)
     }
+    /// Validates the given [`BlobsBundleV1`] and returns versioned hashes for blobs.
+    pub fn validate_blobs_bundle_v2(
+        &self,
+        blobs_bundle: BlobsBundleV2,
+    ) -> Result<Vec<B256>, ValidationApiError> {
+        let versioned_hashes = blobs_bundle
+            .commitments
+            .iter()
+            .map(|c| kzg_to_versioned_hash(c.as_slice()))
+            .collect::<Vec<_>>();
+
+        blobs_bundle
+            .try_into_sidecar()
+            .map_err(|_| ValidationApiError::InvalidBlobsBundle)?
+            .validate(&versioned_hashes, EnvKzgSettings::default().get())?;
+
+        Ok(versioned_hashes)
+    }
 
     /// Core logic for validating the builder submission v3
     async fn validate_builder_submission_v3(
@@ -414,6 +433,35 @@ where
         )
         .await
     }
+
+    /// Core logic for validating the builder submission v5
+    async fn validate_builder_submission_v5(
+        &self,
+        request: BuilderBlockValidationRequestV5,
+    ) -> Result<(), ValidationApiError> {
+        let block = self.payload_validator.ensure_well_formed_payload(ExecutionData {
+            payload: ExecutionPayload::V3(request.request.execution_payload),
+            sidecar: ExecutionPayloadSidecar::v4(
+                CancunPayloadFields {
+                    parent_beacon_block_root: request.parent_beacon_block_root,
+                    versioned_hashes: self
+                        .validate_blobs_bundle_v2(request.request.blobs_bundle)?,
+                },
+                PraguePayloadFields {
+                    requests: RequestsOrHash::Requests(
+                        request.request.execution_requests.to_requests(),
+                    ),
+                },
+            ),
+        })?;
+
+        self.validate_message_against_block(
+            block,
+            request.request.message,
+            request.registered_gas_limit,
+        )
+        .await
+    }
 }
 
 #[async_trait]
@@ -477,6 +525,24 @@ where
 
         rx.await.map_err(|_| internal_rpc_err("Internal blocking task error"))?
     }
+
+    /// Validates a block submitted to the relay
+    async fn validate_builder_submission_v5(
+        &self,
+        request: BuilderBlockValidationRequestV5,
+    ) -> RpcResult<()> {
+        let this = self.clone();
+        let (tx, rx) = oneshot::channel();
+
+        self.task_spawner.spawn_blocking(Box::pin(async move {
+            let result = Self::validate_builder_submission_v5(&this, request)
+                .await
+                .map_err(ErrorObject::from);
+            let _ = tx.send(result);
+        }));
+
+        rx.await.map_err(|_| internal_rpc_err("Internal blocking task error"))?
+    }
 }
 
 pub struct ValidationApiInner<Provider, E: ConfigureEvm> {