Load and use the stored ENR to allow incr of seqNum on updates (#1763)

fluffy/common/common_utils.nim

@@ -50,8 +50,8 @@ proc loadBootstrapFile*(bootstrapFile: string,
 # However that would require the pull the keystore.nim and parts of
 # keystore_management.nim out of nimbus-eth2.
 proc getPersistentNetKey*(
-    rng: var HmacDrbgContext, keyFilePath: string, dataDir: string):
-    PrivateKey =
+    rng: var HmacDrbgContext, keyFilePath: string):
+    tuple[key: PrivateKey, newNetKey: bool] =
   logScope:
     key_file = keyFilePath
 
@@ -69,7 +69,7 @@ proc getPersistentNetKey*(
       let netKey = PrivateKey.fromHex(netKeyInHex)
       if netKey.isOk():
         info "Network key was successfully read"
-        netKey.get()
+        (netKey.get(), false)
       else:
         fatal "Invalid private key from file", error = netKey.error
         quit QuitFailure
@@ -88,4 +88,32 @@ proc getPersistentNetKey*(
 
     info "New network key file was created"
 
-    key
+    (key, true)
+
+proc getPersistentEnr*(enrFilePath: string): Opt[enr.Record] =
+  logScope:
+    enr_file = enrFilePath
+
+  if fileAccessible(enrFilePath, {AccessFlags.Find}):
+    info "ENR file is present, reading ENR"
+
+    let readResult = readAllChars(enrFilePath)
+    if readResult.isErr():
+      warn "Could not load ENR file",
+        error = ioErrorMsg(readResult.error)
+      return Opt.none(enr.Record)
+
+    let enrUri = readResult.get()
+
+    var record: enr.Record
+    # TODO: This old API of var passing is very error prone and should be
+    # changed in nim-eth.
+    if not record.fromURI(enrUri):
+      warn "Could not decode ENR from ENR file"
+      return Opt.none(enr.Record)
+    else:
+      return Opt.some(record)
+
+  else:
+    warn "Could not find ENR file. Was it manually deleted?"
+    return Opt.none(enr.Record)

fluffy/fluffy.nim

@@ -118,15 +118,22 @@ proc run(config: PortalConf) {.raises: [CatchableError].} =
     # TODO: allow for no TCP port mapping!
     (extIp, _, extUdpPort) =
       try: setupAddress(config.nat,
-        config.listenAddress, udpPort, udpPort, "dcli")
+        config.listenAddress, udpPort, udpPort, "fluffy")
       except CatchableError as exc: raise exc
       # TODO: Ideally we don't have the Exception here
       except Exception as exc: raiseAssert exc.msg
-    netkey =
+    (netkey, newNetKey) =
       if config.networkKey.isSome():
-        config.networkKey.get()
+        (config.networkKey.get(), true)
       else:
-        getPersistentNetKey(rng[], config.networkKeyFile, config.dataDir.string)
+        getPersistentNetKey(rng[], config.networkKeyFile)
+
+    enrFilePath = config.dataDir / "fluffy_node.enr"
+    previousEnr =
+      if not newNetKey:
+        getPersistentEnr(enrFilePath)
+      else:
+        Opt.none(enr.Record)
 
   var bootstrapRecords: seq[Record]
   loadBootstrapFile(string config.bootstrapNodesFile, bootstrapRecords)
@@ -152,6 +159,11 @@ proc run(config: PortalConf) {.raises: [CatchableError].} =
       # Might make this into a, default off, cli option.
       localEnrFields = {"c": enrClientInfoShort},
       bootstrapRecords = bootstrapRecords,
+      previousRecord = # TODO: discv5/enr code still uses Option, to be changed.
+        if previousEnr.isSome():
+          some(previousEnr.get())
+        else:
+          none(enr.Record),
       bindIp = bindIp, bindPort = udpPort,
       enrAutoUpdate = config.enrAutoUpdate,
       config = discoveryConfig,