From 1ebba1fac494f4e503b54488a3e1295c13391b7d Mon Sep 17 00:00:00 2001
From: Agnish Ghosh <80243668+agnxsh@users.noreply.github.com>
Date: Mon, 12 Aug 2024 21:27:37 +0530
Subject: [PATCH] add: metadata-v3 for custody subnet count (#6486)

* init: add metadatav3, save progress

* fix import issues

* fix spec version

* fix: metadata_v2 to return altair.MetaData

* update metata function backward compatible now
---
 beacon_chain/networking/eth2_network.nim  | 30 +++++++++++++++++++----
 beacon_chain/networking/peer_protocol.nim |  8 ++++++
 beacon_chain/spec/datatypes/eip7594.nim   |  9 ++++++-
 beacon_chain/spec/presets.nim             |  2 ++
 4 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/beacon_chain/networking/eth2_network.nim b/beacon_chain/networking/eth2_network.nim
index 4e3d6e593..f017bf52b 100644
--- a/beacon_chain/networking/eth2_network.nim
+++ b/beacon_chain/networking/eth2_network.nim
@@ -69,7 +69,7 @@ type
     protocols: seq[ProtocolInfo]
       ## Protocols managed by the DSL and mounted on the switch
     protocolStates*: seq[RootRef]
-    metadata*: altair.MetaData
+    metadata*: eip7594.MetaData
     connectTimeout*: chronos.Duration
     seenThreshold*: chronos.Duration
     connQueue: AsyncQueue[PeerAddr]
@@ -106,7 +106,7 @@ type
     lastReqTime*: Moment
     connections*: int
     enr*: Opt[enr.Record]
-    metadata*: Opt[altair.MetaData]
+    metadata*: Opt[eip7594.MetaData]
     failedMetadataRequests: int
     lastMetadataTime*: Moment
     direction*: PeerType
@@ -1795,7 +1795,7 @@ proc new(T: type Eth2Node,
     let
       connectTimeout = chronos.seconds(10)
       seenThreshold = chronos.seconds(10)
-  type MetaData = altair.MetaData # Weird bug without this..
+  type MetaData = eip7594.MetaData # Weird bug without this..
 
   # Versions up to v22.3.0 would write an empty `MetaData` to
   #`data-dir/node-metadata.json` which would then be reloaded on startup - don't
@@ -2077,12 +2077,32 @@ proc p2pProtocolBackendImpl*(p: P2PProtocol): Backend =
 import ./peer_protocol
 export peer_protocol
 
+proc metadataV2ToV3(metadata: altair.MetaData): eip7594.MetaData =
+  eip7594.MetaData(
+    seq_number: metadata.seq_number,
+    attnets: metadata.attnets,
+    syncnets: metadata.syncnets)
+
+proc getMetadata_vx(node: Eth2Node, peer: Peer): 
+                    Future[NetRes[eip7594.MetaData]]
+                   {.async: (raises: [CancelledError]).} =
+  let
+    res = 
+      if node.cfg.EIP7594_FORK_EPOCH != FAR_FUTURE_EPOCH:
+        # Directly fetch eip7594 metadata if available
+        await getMetadata_v3(peer)
+      else:
+        let metadata_v2_result = await getMetadata_v2(peer)
+        metadata_v2_result.map(proc (altairData: altair.MetaData): eip7594.MetaData {.closure.} =
+          metadataV2ToV3(altairData)
+        )
+  return res
+
 proc updatePeerMetadata(node: Eth2Node, peerId: PeerId) {.async: (raises: [CancelledError]).} =
   trace "updating peer metadata", peerId
-
   let
     peer = node.getPeer(peerId)
-    newMetadataRes = await peer.getMetadata_v2()
+    newMetadataRes = await node.getMetadata_vx(peer)
     newMetadata = newMetadataRes.valueOr:
       debug "Failed to retrieve metadata from peer!", peerId, error = newMetadataRes.error
       peer.failedMetadataRequests.inc()
diff --git a/beacon_chain/networking/peer_protocol.nim b/beacon_chain/networking/peer_protocol.nim
index ff47b17dd..59efc8709 100644
--- a/beacon_chain/networking/peer_protocol.nim
+++ b/beacon_chain/networking/peer_protocol.nim
@@ -177,6 +177,14 @@ p2pProtocol PeerSync(version = 1,
 
   proc getMetadata_v2(peer: Peer): altair.MetaData
     {.libp2pProtocol("metadata", 2).} =
+    let altair_metadata = altair.MetaData(
+      seq_number: peer.network.metadata.seq_number,
+      attnets: peer.network.metadata.attnets,
+      syncnets: peer.network.metadata.syncnets)
+    altair_metadata
+
+  proc getMetadata_v3(peer: Peer): eip7594.MetaData
+    {.libp2pProtocol("metadata", 3).} =
     peer.network.metadata
 
   proc goodbye(peer: Peer, reason: uint64)
diff --git a/beacon_chain/spec/datatypes/eip7594.nim b/beacon_chain/spec/datatypes/eip7594.nim
index 8ba81174b..317bb2c18 100644
--- a/beacon_chain/spec/datatypes/eip7594.nim
+++ b/beacon_chain/spec/datatypes/eip7594.nim
@@ -9,7 +9,7 @@
 
 import
   std/[sequtils],
-  "."/[base, deneb], 
+  "."/[altair, base, deneb], 
   kzg4844,
   stew/[byteutils]
 
@@ -79,6 +79,13 @@ type
 
   CscBits* = BitArray[DATA_COLUMN_SIDECAR_SUBNET_COUNT]
 
+  # https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.4/specs/_features/eip7594/p2p-interface.md#metadata
+  MetaData* = object
+    seq_number*: uint64
+    attnets*: AttnetBits
+    syncnets*: SyncnetBits
+    custody_subnet_count*: uint64 
+
 # func serializeDataColumn(data_column: DataColumn): auto =
 #   var counter = 0
 #   var serd : array[MAX_BLOB_COMMITMENTS_PER_BLOCK * BYTES_PER_CELL, byte]
diff --git a/beacon_chain/spec/presets.nim b/beacon_chain/spec/presets.nim
index 482f9501d..d8785505e 100644
--- a/beacon_chain/spec/presets.nim
+++ b/beacon_chain/spec/presets.nim
@@ -60,6 +60,8 @@ type
     CAPELLA_FORK_EPOCH*: Epoch
     DENEB_FORK_VERSION*: Version
     DENEB_FORK_EPOCH*: Epoch
+    EIP7594_FORK_VERSION*: Version
+    EIP7594_FORK_EPOCH*: Epoch
     ELECTRA_FORK_VERSION*: Version
     ELECTRA_FORK_EPOCH*: Epoch