Setup agent/proto version identifiers in libp2p. (#2079)

* Supply `nim-libp2p` with `agent-string` and `proto-string` as configured parameters.

* Remove protoString and rng check.

* Fix compilation problem.

beacon_chain/conf.nim

@@ -103,6 +103,11 @@ type
             "file (default: false)"
       name: "insecure-netkey-password" }: bool
 
+    agentString* {.
+      defaultValue: "nimbus",
+      desc: "Node agent string which is used as identifier in network"
+      name: "agent-string" }: string
+
     case cmd* {.
       command
       defaultValue: noCommand }: BNStartUpCmd

beacon_chain/eth2_network.nim

@@ -11,10 +11,12 @@ import
   json_serialization, json_serialization/std/[net, options],
   chronos, chronicles, metrics,
   # TODO: create simpler to use libp2p modules that use re-exports
-  libp2p/[switch, standard_setup, peerinfo,
+  libp2p/[switch, peerinfo,
           multiaddress, multicodec, crypto/crypto, crypto/secp,
           protocols/identify, protocols/protocol],
-  libp2p/protocols/secure/[secure, secio],
+  libp2p/muxers/muxer, libp2p/muxers/mplex/mplex,
+  libp2p/transports/[transport, tcptransport],
+  libp2p/protocols/secure/[secure, noise],
   libp2p/protocols/pubsub/[pubsub, rpc/message, rpc/messages],
   libp2p/transports/tcptransport,
   libp2p/stream/connection,
@@ -1499,6 +1501,25 @@ func msgIdProvider(m: messages.Message): seq[byte] =
   except CatchableError:
     gossipId(m.data, false)
 
+proc newBeaconSwitch*(conf: BeaconNodeConf, seckey: PrivateKey,
+                      address: MultiAddress,
+                      rng: ref BrHmacDrbgContext): Switch =
+  proc createMplex(conn: Connection): Muxer =
+    Mplex.init(conn, inTimeout = 5.minutes, outTimeout = 5.minutes)
+
+  let
+    peerInfo = PeerInfo.init(seckey, [address])
+    mplexProvider = newMuxerProvider(createMplex, MplexCodec)
+    transports = @[Transport(TcpTransport.init({ServerFlags.ReuseAddr}))]
+    muxers = {MplexCodec: mplexProvider}.toTable
+    secureManagers = [Secure(newNoise(rng, seckey))]
+
+  peerInfo.agentVersion = conf.agentString
+
+  let identify = newIdentify(peerInfo)
+
+  newSwitch(peerInfo, transports, identify, muxers, secureManagers)
+
 proc createEth2Node*(rng: ref BrHmacDrbgContext,
                      conf: BeaconNodeConf,
                      netKeys: KeyPair,
@@ -1516,12 +1537,7 @@ proc createEth2Node*(rng: ref BrHmacDrbgContext,
   # TODO nim-libp2p still doesn't have support for announcing addresses
   # that are different from the host address (this is relevant when we
   # are running behind a NAT).
-  var switch = newStandardSwitch(some netKeys.seckey, hostAddress,
+  var switch = newBeaconSwitch(conf, netKeys.seckey, hostAddress, rng)
-                                 transportFlags = {ServerFlags.ReuseAddr},
-                                 secureManagers = [
-                                   SecureProtocol.Noise, # Only noise in ETH2!
-                                 ],
-                                 rng = rng)
 
   let
     params =