add: logic constructing valid set of peers

beacon_chain/networking/eth2_network.nim

@@ -27,7 +27,8 @@ import
   eth/net/nat, eth/p2p/discoveryv5/[enr, node, random2],
   ".."/[version, conf, beacon_clock, conf_light_client],
   ../spec/datatypes/[phase0, altair, bellatrix, eip7594],
-  ../spec/[eth2_ssz_serialization, network, helpers, forks],
+  ../spec/[eth2_ssz_serialization, network, 
+    helpers, eip7594_helpers, forks],
   ../validators/keystore_management,
   "."/[eth2_discovery, eth2_protocol_dsl, libp2p_json_serialization, peer_pool, peer_scores]
 
@@ -1482,7 +1483,8 @@ proc trimConnections(node: Eth2Node, count: int) =
     inc(nbc_cycling_kicked_peers)
     if toKick <= 0: return
 
-proc getLowSubnets(node: Eth2Node, epoch: Epoch): (AttnetBits, SyncnetBits, CscBits) =
+proc getLowSubnets(node: Eth2Node, epoch: Epoch): 
+                  (AttnetBits, SyncnetBits, CscBits) =
   # Returns the subnets required to have a healthy mesh
   # The subnets are computed, to, in order:
   # - Have 0 subnet with < `dLow` peers from topic subscription
@@ -1575,7 +1577,11 @@ proc runDiscoveryLoop(node: Eth2Node) {.async.} =
           else:
             0
         discoveredNodes = await node.discovery.queryRandom(
-          node.discoveryForkId, wantedAttnets, wantedSyncnets, wantedCscnets, minScore)
+          node.discoveryForkId,
+          wantedAttnets,
+          wantedSyncnets,
+          wantedCscnets,
+          minScore)
 
       let newPeers = block:
         var np = newSeq[PeerAddr]()
@@ -1624,6 +1630,97 @@ proc runDiscoveryLoop(node: Eth2Node) {.async.} =
     # Also, give some time to dial the discovered nodes and update stats etc
     await sleepAsync(5.seconds)
 
+proc getNodeIdFromPeer*(peer: Peer): NodeId=
+  # Convert peer id to node id by extracting the peer's public key
+  let nodeId =
+    block:
+      var key: PublicKey
+      discard peer.peerId.extractPublicKey(key)
+      keys.PublicKey.fromRaw(key.skkey.getBytes()).get().toNodeId()
+  nodeId
+
+proc fetchCustodyColumnCountFromRemotePeer*(node: Eth2Node,
+                                            pid: PeerId):
+                                            uint64 =
+  # Fetches the custody column count from a remote peer
+  # if the peer advertises their custody column count 
+  # via the `csc` ENR field. If the peer does NOT, then
+  # the default value is assume, i.e, CUSTODY_REQUIREMENT
+  let 
+    eth2node = node
+    peer = eth2node.getPeer(pid)
+
+  let enrOpt = peer.enr
+  if enrOpt.isNone:
+    debug "Could not get ENR from peer",
+      peer_id = pid
+    return 0
+
+  else:
+    let
+      enr = enrOpt.get
+      enrFieldOpt = 
+          enr.get(enrCustodySubnetCountField, uint64)
+
+    if not enrFieldOpt.isOk:
+      debug "Issue with fetching `csc` field from ENR",
+        enr = enr
+    else:
+      return(enrFieldOpt.get)
+
+proc constructValidCustodyPeers*(node: Eth2Node,
+                                 peers: openArray[Peer],
+                                 config: BeaconNodeConf):
+                                 seq[PeerId] =
+  # `constructValidaCustodyPeers` returns a list of peers that are an overall
+  # superset of the given local node's custody columns and the custody columns
+  # of the remote peers
+
+  # Get the local custody subnet count
+  var localCustodySubnetCount: uint64
+  if config.subscribeAllSubnets:
+    localCustodySubnetCount = DATA_COLUMN_SIDECAR_SUBNET_COUNT.uint64
+  localCustodySubnetCount = CUSTODY_REQUIREMENT
+
+  # Get the local custody columns
+  let 
+    localNodeId = node.nodeId
+    localCustodyColumns = 
+        localNodeId.get_custody_columns(localCustodySubnetCount).get
+
+  var validPeerIds = newSeqOfCap[PeerId](peers.len)
+
+  for peer in peers:
+    # Get the custody subnet counts of the remote peer
+    let remoteCustodySubnetCount = 
+        node.fetchCustodyColumnCountFromRemotePeer(peer.peerId)
+
+    # Extract remote peer's nodeID from peerID
+    # Fetch custody columns fromm remote peer
+    let 
+      remoteNodeId = getNodeIdFromPeer(peer)
+      remoteCustodyColumns = 
+          remoteNodeId.get_custody_columns(remoteCustodySubnetCount).get
+
+    # If the remote peer custodies less columns than our local node
+    # We skip it
+    if remoteCustodyColumns.len < localCustodyColumns.len:
+      continue
+
+    # If the remote peer custodies all the possible columns
+    if remoteCustodyColumns.len == NUMBER_OF_COLUMNS:
+      validPeerIds.add(peer.peerId)
+
+    # Filtering out the invalid peers
+    for column in localCustodyColumns:
+      if column notin remoteCustodyColumns:
+        continue
+    
+    # Otherwise add the peer to the set
+    # of valid peerIds
+    validPeerIds.add(peer.peerId)
+  validPeerIds
+
 proc resolvePeer(peer: Peer) =
   # Resolve task which performs searching of peer's public key and recovery of
   # ENR using discovery5. We only resolve ENR for peers we know about to avoid

beacon_chain/nimbus_beacon_node.nim

@@ -1136,32 +1136,6 @@ proc fetchCustodySubnetCount* (node: BeaconNode): uint64=
     res = DATA_COLUMN_SIDECAR_SUBNET_COUNT.uint64
   res
 
-proc fetchCustodyColumnCountFromRemotePeer*(node: BeaconNode, pid: PeerId): uint64 =
-  # Fetches the custody column count from a remote peer
-  # if the peer advertises their custody column count 
-  # via the `csc` ENR field. If the peer does NOT, then
-  # the default value is assume, i.e, CUSTODY_REQUIREMENT
-  let 
-    eth2node = node.network
-    peer = eth2node.getPeer(pid)
-
-  let enrOpt = peer.enr
-  if enrOpt.isNone:
-    debug "Could not get ENR from peer",
-      peer_id = pid
-    return 0
-
-  else:
-    let
-      enr = enrOpt.get
-      enrFieldOpt = enr.get(enrCustodySubnetCountField, uint64)
-
-    if not enrFieldOpt.isOk:
-      debug "Issue with fetching `csc` field from ENR",
-        enr = enr
-    else:
-      return(enrFieldOpt.get)
-
 proc addDenebMessageHandlers(
     node: BeaconNode, forkDigest: ForkDigest, slot: Slot) =
   node.addCapellaMessageHandlers(forkDigest, slot)