Testnet compatible network upgrade (#587)

* Create libp2p instance

* Change logger to stdlog

* test_connection initial commit

* Add gossipsub test

* Delete tests in network crate

* Add test module

* Clean tests

* Remove dependency on discovery

* Working publish between 2 nodes
TODO: Publish should be called just once

* Working 2 peer gossipsub test with additional events

* Cleanup test

* Add rpc test

* Star topology discovery WIP

* build_nodes builds and connects n nodes. Increase nodes in gossipsub test

* Add unsubscribe method and expose reference to gossipsub object for gossipsub tests

* Add gossipsub message forwarding test

* Fix gossipsub forward test

* Test improvements
* Remove discovery tests
* Simplify gossipsub forward test topology
* Add helper functions for topology building

* Clean up tests

* Update naming to new network spec

* Correct ssz encoding of protocol names

* Further additions to network upgrade

* Initial network spec update WIP

* Temp commit

* Builds one side of the streamed RPC responses

* Temporary commit

* Propagates streaming changes up into message handler

* Intermediate network update

* Partial update in upgrading to the new network spec

* Update dependencies, remove redundant deps

* Correct sync manager for block stream handling

* Re-write of RPC handler, improves efficiency and corrects bugs

* Stream termination update

* Completed refactor of rpc handler

* Remove crates

* Correct compile issues associated with test merge

* Build basic tests and testing structure for eth2-libp2p

* Enhance RPC tests and add logging

* Complete RPC testing framework and STATUS test

* Decoding bug fixes, log improvements, stream test

* Clean up RPC handler logging

* Decoder bug fix, empty block stream test

* Add BlocksByRoot RPC test

* Add Goodbye RPC test

* Syncing and stream handling bug fixes and performance improvements

* Applies discv5 bug fixes

* Adds DHT IP filtering for lighthouse - currently disabled

* Adds randomized network propagation as a CLI arg

* Add disconnect functionality

* Adds attestation handling and parent lookup

* Adds RPC error handling for the sync manager

* Allow parent's blocks to be already processed

* Update github workflow

* Adds reviewer suggestions

beacon_node/eth2-libp2p/src/discovery.rs

@@ -18,7 +18,7 @@ use std::path::Path;
 use std::str::FromStr;
 use std::time::{Duration, Instant};
 use tokio::io::{AsyncRead, AsyncWrite};
-use tokio_timer::Delay;
+use tokio::timer::Delay;
 
 /// Maximum seconds before searching for extra peers.
 const MAX_TIME_BETWEEN_PEER_SEARCHES: u64 = 60;
@@ -33,6 +33,9 @@ pub struct Discovery<TSubstream> {
     /// The peers currently connected to libp2p streams.
     connected_peers: HashSet<PeerId>,
 
+    /// The currently banned peers.
+    banned_peers: HashSet<PeerId>,
+
     /// The target number of connected peers on the libp2p interface.
     max_peers: usize,
 
@@ -77,7 +80,10 @@ impl<TSubstream> Discovery<TSubstream> {
         info!(log, "ENR Initialised"; "ENR" => local_enr.to_base64(), "Seq" => local_enr.seq());
         debug!(log, "Discv5 Node ID Initialised"; "node_id" => format!("{}",local_enr.node_id()));
 
-        let mut discovery = Discv5::new(local_enr, local_key.clone(), config.listen_address)
+        // the last parameter enables IP limiting. 2 Nodes on the same /24 subnet per bucket and 10
+        // nodes on the same /24 subnet per table.
+        // TODO: IP filtering is currently disabled for the DHT. Enable for production
+        let mut discovery = Discv5::new(local_enr, local_key.clone(), config.listen_address, false)
             .map_err(|e| format!("Discv5 service failed. Error: {:?}", e))?;
 
         // Add bootnodes to routing table
@@ -93,6 +99,7 @@ impl<TSubstream> Discovery<TSubstream> {
 
         Ok(Self {
             connected_peers: HashSet::new(),
+            banned_peers: HashSet::new(),
             max_peers: config.max_peers,
             peer_discovery_delay: Delay::new(Instant::now()),
             past_discovery_delay: INITIAL_SEARCH_DELAY,
@@ -147,6 +154,14 @@ impl<TSubstream> Discovery<TSubstream> {
         &self.connected_peers
     }
 
+    /// The peer has been banned. Add this peer to the banned list to prevent any future
+    /// re-connections.
+    // TODO: Remove the peer from the DHT if present
+    // TODO: Implement a timeout, after which we unban the peer
+    pub fn peer_banned(&mut self, peer_id: PeerId) {
+        self.banned_peers.insert(peer_id);
+    }
+
     /// Search for new peers using the underlying discovery mechanism.
     fn find_peers(&mut self) {
         // pick a random NodeId
@@ -271,6 +286,7 @@ where
                                 // if we need more peers, attempt a connection
                                 if self.connected_peers.len() < self.max_peers
                                     && self.connected_peers.get(&peer_id).is_none()
+                                    && !self.banned_peers.contains(&peer_id)
                                 {
                                     debug!(self.log, "Peer discovered"; "peer_id"=> format!("{:?}", peer_id));
                                     return Async::Ready(NetworkBehaviourAction::DialPeer {