From 38271784c2b31926563806da9a2e023b88f5e7a8 Mon Sep 17 00:00:00 2001
From: Bosul Mun <bosul.mun@ethereum.org>
Date: Tue, 28 Jul 2026 07:13:32 +0200
Subject: [PATCH] eth/protocols: fix Cells/GetCells RLP encoding (#35428)

This PR aligns the `Cells` and `GetCells` message implementations with
the spec: https://github.com/ethereum/devp2p/blob/master/caps/eth.md#getcells-0x14

Previously, `GetCellsPacket` and `CellsPacket` embedded `GetCellsRequest`
and `CellsResponse`. This caused them to be encoded as nested lists, which
does not match the wire format defined by the spec. This PR inlines their fields
to flatten the RLP layout of `Cells` and `GetCells`.
---
 eth/protocols/eth/handlers.go | 10 +++++++---
 eth/protocols/eth/peer.go     | 14 +++++---------
 eth/protocols/eth/protocol.go |  7 +++++--
 3 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/eth/protocols/eth/handlers.go b/eth/protocols/eth/handlers.go
index 4beb0a7f48..bf02c0f8e0 100644
--- a/eth/protocols/eth/handlers.go
+++ b/eth/protocols/eth/handlers.go
@@ -694,7 +694,7 @@ func handleGetCells(backend Backend, msg Decoder, peer *Peer) error {
 	if err := msg.Decode(&query); err != nil {
 		return err
 	}
-	hashes, cells, custody := answerGetCells(backend, query.GetCellsRequest)
+	hashes, cells, custody := answerGetCells(backend, GetCellsRequest{Hashes: query.Hashes, Mask: query.Mask})
 	return peer.ReplyCells(query.RequestId, hashes, cells, custody)
 }
 
@@ -754,12 +754,16 @@ func handleCells(backend Backend, msg Decoder, peer *Peer) error {
 	tresp := tracker.Response{
 		ID:      cellsResponse.RequestId,
 		MsgCode: CellsMsg,
-		Size:    cellsResponse.CellsResponse.Cells.Len(),
+		Size:    cellsResponse.Cells.Len(),
 	}
 	if err := peer.tracker.Fulfil(tresp); err != nil {
 		return fmt.Errorf("Cells: %w", err)
 	}
-	return backend.Handle(peer, &cellsResponse.CellsResponse)
+	return backend.Handle(peer, &CellsResponse{
+		Hashes: cellsResponse.Hashes,
+		Cells:  cellsResponse.Cells,
+		Mask:   cellsResponse.Mask,
+	})
 }
 
 // handleGetBlockAccessLists serves a GetBlockAccessLists request.
diff --git a/eth/protocols/eth/peer.go b/eth/protocols/eth/peer.go
index 61debbeadb..21810126d2 100644
--- a/eth/protocols/eth/peer.go
+++ b/eth/protocols/eth/peer.go
@@ -273,11 +273,9 @@ func (p *Peer) ReplyCells(id uint64, hashes []common.Hash, cells [][]kzg4844.Cel
 	}
 	return p2p.Send(p.rw, CellsMsg, &CellsPacket{
 		RequestId: id,
-		CellsResponse: CellsResponse{
-			Hashes: hashes,
-			Cells:  rawCells,
-			Mask:   mask,
-		},
+		Hashes:    hashes,
+		Cells:     rawCells,
+		Mask:      mask,
 	})
 }
 
@@ -297,10 +295,8 @@ func (p *Peer) RequestPayload(hashes []common.Hash, cell types.CustodyBitmap) er
 	}
 	return p2p.Send(p.rw, GetCellsMsg, &GetCellsRequestPacket{
 		RequestId: id,
-		GetCellsRequest: GetCellsRequest{
-			Hashes: hashes,
-			Mask:   cell,
-		},
+		Hashes:    hashes,
+		Mask:      cell,
 	})
 }
 
diff --git a/eth/protocols/eth/protocol.go b/eth/protocols/eth/protocol.go
index 6dd1e8bec3..a7df9e7408 100644
--- a/eth/protocols/eth/protocol.go
+++ b/eth/protocols/eth/protocol.go
@@ -314,7 +314,8 @@ type GetCellsRequest struct {
 // GetCellsRequestPacket represents a cell request with request ID wrapping.
 type GetCellsRequestPacket struct {
 	RequestId uint64
-	GetCellsRequest
+	Hashes    []common.Hash
+	Mask      types.CustodyBitmap
 }
 
 // CellsResponse represents a response containing cells for blob transactions.
@@ -327,7 +328,9 @@ type CellsResponse struct {
 // CellsPacket represents a cells response with request ID wrapping.
 type CellsPacket struct {
 	RequestId uint64
-	CellsResponse
+	Hashes    []common.Hash
+	Cells     rlp.RawList[rlp.RawList[kzg4844.Cell]]
+	Mask      types.CustodyBitmap
 }
 
 type GetBlockAccessListsRequest []common.Hash