From 57974ce61be35132da0e0108ee1ed1c9bdf68e52 Mon Sep 17 00:00:00 2001
From: tersec <tersec@users.noreply.github.com>
Date: Fri, 17 Dec 2021 12:23:32 +0000
Subject: [PATCH] forkchoiceUpdate support (#3199)

---
 beacon_chain/eth1/eth1_monitor.nim           | 15 +++++++++++++++
 beacon_chain/validators/validator_duties.nim | 19 +++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/beacon_chain/eth1/eth1_monitor.nim b/beacon_chain/eth1/eth1_monitor.nim
index 10e97f2f95..122ba56747 100644
--- a/beacon_chain/eth1/eth1_monitor.nim
+++ b/beacon_chain/eth1/eth1_monitor.nim
@@ -421,6 +421,21 @@ proc executePayload*(p: Web3DataProviderRef,
                      payload: engine_api.ExecutionPayloadV1): Future[ExecutePayloadResponse] =
   p.web3.provider.engine_executePayloadV1(payload)
 
+proc forkchoiceUpdated*(p: Web3DataProviderRef,
+                        headBlock, finalizedBlock: Eth2Digest):
+                        Future[engine_api.ForkchoiceUpdatedResponse] =
+  p.web3.provider.engine_forkchoiceUpdatedV1(
+    ForkchoiceStateV1(
+      headBlockHash: headBlock.asBlockHash,
+
+      # https://hackmd.io/@n0ble/kintsugi-spec#Engine-API
+      # "CL client software MUST use headBlockHash value as a stub for the
+      # safeBlockHash parameter"
+      safeBlockHash: headBlock.asBlockHash,
+
+      finalizedBlockHash: finalizedBlock.asBlockHash),
+    none(engine_api.PayloadAttributesV1))
+
 proc forkchoiceUpdated*(p: Web3DataProviderRef,
                         headBlock, finalizedBlock: Eth2Digest,
                         timestamp: uint64,
diff --git a/beacon_chain/validators/validator_duties.nim b/beacon_chain/validators/validator_duties.nim
index e750d57375..2bda7bc17f 100644
--- a/beacon_chain/validators/validator_duties.nim
+++ b/beacon_chain/validators/validator_duties.nim
@@ -18,6 +18,7 @@ import
   json_serialization/std/[options, sets, net], serialization/errors,
   eth/db/kvstore,
   eth/keys, eth/p2p/discoveryv5/[protocol, enr],
+  web3/ethtypes,
 
   # Local modules
   ../spec/datatypes/[phase0, altair, merge],
@@ -416,6 +417,24 @@ proc getBlockProposalEth1Data*(node: BeaconNode,
       state, finalizedEpochRef.eth1_data,
       finalizedEpochRef.eth1_deposit_index)
 
+proc forkchoice_updated(state: merge.BeaconState,
+                        head_block_hash: Eth2Digest,
+                        finalized_block_hash: Eth2Digest,
+                        fee_recipient: ethtypes.Address,
+                        execution_engine: Web3DataProviderRef):
+                        Future[Option[merge.PayloadId]] {.async.} =
+  let
+    timestamp = compute_timestamp_at_slot(state, state.slot)
+    random = get_randao_mix(state, get_current_epoch(state))
+    payloadId =
+      (await execution_engine.forkchoiceUpdated(
+        head_block_hash, finalized_block_hash, timestamp, random.data,
+        fee_recipient)).payloadId
+  return if payloadId.isSome:
+    some(merge.PayloadId(payloadId.get))
+  else:
+    none(merge.PayloadId)
+
 proc makeBeaconBlockForHeadAndSlot*(node: BeaconNode,
                                     randao_reveal: ValidatorSig,
                                     validator_index: ValidatorIndex,