Discovery patch (#2382)

* Upgrade libp2p and unstable gossip

* Network protocol upgrades

* Correct dependencies, reduce incoming bucket limit

* Clean up dirty DHT entries before repopulating

* Update cargo lock

* Update lockfile

* Update ENR dep

* Update deps to specific versions

* Update test dependencies

* Update docker rust, and remote signer tests

* More remote signer test fixes

* Temp commit

* Update discovery

* Remove cached enrs after dialing

* Increase the session capacity, for improved efficiency

beacon_node/eth2_libp2p/src/discovery/mod.rs

@@ -295,6 +295,11 @@ impl<TSpec: EthSpec> Discovery<TSpec> {
         self.cached_enrs.iter()
     }
 
+    /// Removes a cached ENR from the list.
+    pub fn remove_cached_enr(&mut self, peer_id: &PeerId) -> Option<Enr> {
+        self.cached_enrs.pop(peer_id)
+    }
+
     /// This adds a new `FindPeers` query to the queue if one doesn't already exist.
     pub fn discover_peers(&mut self) {
         // If the discv5 service isn't running or we are in the process of a query, don't bother queuing a new one.
@@ -502,6 +507,7 @@ impl<TSpec: EthSpec> Discovery<TSpec> {
         }
     }
 
+    /// Unbans the peer in discovery.
     pub fn unban_peer(&mut self, peer_id: &PeerId, ip_addresses: Vec<IpAddr>) {
         // first try and convert the peer_id to a node_id.
         if let Ok(node_id) = peer_id_to_node_id(peer_id) {
@@ -514,11 +520,15 @@ impl<TSpec: EthSpec> Discovery<TSpec> {
         }
     }
 
-    // mark node as disconnected in DHT, freeing up space for other nodes
+    ///  Marks node as disconnected in the DHT, freeing up space for other nodes, this also removes
+    ///  nodes from the cached ENR list.
     pub fn disconnect_peer(&mut self, peer_id: &PeerId) {
         if let Ok(node_id) = peer_id_to_node_id(peer_id) {
             self.discv5.disconnect_node(&node_id);
         }
+        // Remove the peer from the cached list, to prevent redialing disconnected
+        // peers.
+        self.cached_enrs.pop(peer_id);
     }
 
     /* Internal Functions */