Updated networking flow (markdown)

networking-flow.md

@@ -6,23 +6,58 @@ beacon_chain/beacon_node.nim:
 
 - BeaconNode.start()
   - waitsFor node.connectToNetwork()
+
 - BeaconNode.connectToNetwork()
   - awaits node.network.connectToNetwork(node.bootstrapNodes, node.bootstrapEnrs)
 
 beacon_chain/eth2_network.nim:
 
 - Eth2Node.connectToNetwork(seq[ENode], seq[enr.Record])
-  - for each bootstrap ENR, calls Eth2Node.addKnownPeer() which calls discovery `addNode`, which effectively adds the node to the routing table.
+  - for each bootstrap ENR, calls Eth2Node.addKnownPeer()
   - awaits Eth2Node.start()
+  - waits 30 seconds and checks if there was at least one successful connection to a bootstrap node
 
 beacon_chain/libp2p_backend.nim:
 
+- Eth2Node.addKnownPeer()
+  - calls eth.p2p.discoveryv5.Protocol.addNode(enr.Record)
+
 - Eth2Node.start()
   - calls Eth2DiscoveryProtocol.open()
   - calls Eth2DiscoveryProtocol.start() - currently nop
   - awaits Switch.start() and stores the resulting seq[Future[void]] in Eth2Node.libp2pTransportLoops; nothing further is done with those futures
   - tracesAsyncErrors Eth2Node.runDiscoveryLoop(), which discovers peers and runs `dialPeer` for each discovered peer.
 
+- Eth2Node.runDiscoveryLoop()
+  - in an endless loop, while more peers are wanted, awaits eth.p2p.discoveryv5.Protocol.lookupRandom()
+  - for each discovered peer, awaits Eth2Node.dialPeer(PeerInfo)
+
+- Eth2Node.dialPeer(PeerInfo)
+  - awaits Switch.connect(PeerInfo)
+  - awaits Peer.initializeConnection()
+
+beacon_chain/libp2p_backends_common.nim:
+
+- Peer.initializeConnection()
+  - calls Peer.performProtocolHandshakes()
+
+- Peer.performProtocolHandshakes()
+  - for each ProtocolInfo instance in a global var, calls its `handshake` member which is a HandshakeStep proc
+
+## discovery
+
+vendor/nim-eth/eth/p2p/discoveryv5/protocol.nim:
+
+- Protocol.addNode(enr.Record)
+  - calls RoutingTable.addNode(Node)
+
+- Protocol.lookupRandom()
+  - calls Protocol.lookup(NodeId) on a random UInt256
+
+- Protocol.lookup(NodeId)
+  - calls RoutingTable.neighbours()
+  - calls Protocol.lookupWorker() in a busy loop
+
 ## switch
 
 vendor/nim-libp2p/libp2p/switch.nim:
@@ -31,15 +66,18 @@ vendor/nim-libp2p/libp2p/switch.nim:
   - for each Switch.transports and each Switch.peerInfo awaits Transport.listen(MultiAddress, Switch.start.handle)
   - (returns a seq of these futures)
   - awaits PubSub.start() on Switch.pubSub
+
 - Switch.start.handle(Connection)
   - awaits Switch.upgradeIncoming(Connection)
   - awaits Connection.close()
   - awaits Switch.cleanupConn(Connection)
+
 - Switch.upgradeIncoming(Connection)
   - creates a local MultistreamSelect instance
   - awaits MultistreamSelect.select(Connection)
   - for each protocol string key in Switch.secureManagers, calls MultistreamSelect.addHandler(proto: string, Switch.upgradeIncoming.securedHandler)
   - awaits MultistreamSelect.handle(Connection)
+
 - Switch.upgradeIncoming.securedHandler(Connection, proto: string)
   - awaits Secure.secure(Connection) and saves the result in `sconn` - this seems to be the same as `conn`
   - for each MuxerProvider value in Switch.muxers, calls MultistreamSelect.addHandler(MuxerProvider.codec, MuxerProvider)
@@ -51,11 +89,13 @@ vendor/nim-libp2p/libp2p/multistream.nim:
 
 - MultistreamSelect.select(Connection, proto: string)
   - calls MultistreamSelect.select(Connection, @[proto])
+
 - MultistreamSelect.select(Connection, proto: seq[string])
   - awaits Connection.write(codec: string)
   - if there's a `proto` argument, it awaits Connection.writeLp() - only on the first seq item
   - awaits Connection.readLp() (without the trailing newline; this header is ignored)
   - if there's a `proto`, awaits Connection.readLp() - if it's the same string as the requested protocol, it returns it
   - if the response was "\n", it tries any other proto in that seq
+
 - MultistreamSelect.handle(Connection)
   - in a loop: awaits Connection.readLp() for a proto string and if it matches with a MultistreamSelect.handlers instance, it calls HandleHolder.protocol.handler(Connection, proto) - this handler is an LPProtoHandler proc type and it's Switch.upgradeIncoming.securedHandler() or a MuxerProvider.handler() from Switch.muxers which is usually MuxerProvider.init.handler() that does nothing