Experimental discovery (#2577)

# Description

A few changes have been made to discovery. In particular a custom re-write of an LRU cache which previously was read/write O(N) for all our sessions ~5k, to a more reasonable hashmap-style O(1). 

Further there has been reported issues in the current discv5, so added error handling to help identify the issue has been added.

beacon_node/eth2_libp2p/Cargo.toml

@@ -5,7 +5,8 @@ authors = ["Sigma Prime <contact@sigmaprime.io>"]
 edition = "2018"
 
 [dependencies]
-discv5 = { version = "0.1.0-beta.9", features = ["libp2p"] }
+#discv5 = { version = "0.1.0-beta.10", features = ["libp2p"] }
+discv5 = { git = "https://github.com/sigp/discv5", rev="10247bbd299227fef20233f2f5a8de9780de09ac", features = ["libp2p"] }
 unsigned-varint = { version = "0.6.0", features = ["codec"] }
 types = { path =  "../../consensus/types" }
 hashset_delay = { path = "../../common/hashset_delay" }

boot_node/src/config.rs

@@ -1,6 +1,6 @@
 use beacon_node::{get_data_dir, get_eth2_network_config, set_network_config};
 use clap::ArgMatches;
-use eth2_libp2p::discv5::{enr::CombinedKey, Enr};
+use eth2_libp2p::discv5::{enr::CombinedKey, Discv5Config, Enr};
 use eth2_libp2p::{
     discovery::{create_enr_builder_from_config, load_enr_from_disk, use_or_load_enr},
     load_private_key, CombinedKeyExt, NetworkConfig,
@@ -18,8 +18,7 @@ pub struct BootNodeConfig<T: EthSpec> {
     pub boot_nodes: Vec<Enr>,
     pub local_enr: Enr,
     pub local_key: CombinedKey,
-    pub auto_update: bool,
-    pub disable_packet_filter: bool,
+    pub discv5_config: Discv5Config,
     phantom: PhantomData<T>,
 }
 
@@ -58,19 +57,16 @@ impl<T: EthSpec> TryFrom<&ArgMatches<'_>> for BootNodeConfig<T> {
         let logger = slog_scope::logger();
 
         set_network_config(&mut network_config, matches, &data_dir, &logger, true)?;
-        // default to the standard port
+
+        // Set the enr-udp-port to the default listening port if it was not specified.
         if !matches.is_present("enr-udp-port") {
-            network_config.enr_udp_port = Some(
-                matches
-                    .value_of("port")
-                    .expect("Value required")
-                    .parse()
-                    .map_err(|_| "Invalid port number")?,
-            );
+            network_config.enr_udp_port = Some(network_config.discovery_port);
         }
 
-        let auto_update = matches.is_present("enable-enr_auto_update");
-        let disable_packet_filter = matches.is_present("disable-packet-filter");
+        // By default this is enabled. If it is not set, revert to false.
+        if !matches.is_present("enable-enr-auto-update") {
+            network_config.discv5_config.enr_update = false;
+        }
 
         // the address to listen on
         let listen_socket =
@@ -129,8 +125,7 @@ impl<T: EthSpec> TryFrom<&ArgMatches<'_>> for BootNodeConfig<T> {
             boot_nodes,
             local_enr,
             local_key,
-            auto_update,
-            disable_packet_filter,
+            discv5_config: network_config.discv5_config,
             phantom: PhantomData,
         })
     }

boot_node/src/server.rs

@@ -2,7 +2,7 @@
 
 use super::BootNodeConfig;
 use eth2_libp2p::{
-    discv5::{enr::NodeId, Discv5, Discv5ConfigBuilder, Discv5Event},
+    discv5::{enr::NodeId, Discv5, Discv5Event},
     EnrExt, Eth2Enr,
 };
 use slog::info;
@@ -26,24 +26,13 @@ pub async fn run<T: EthSpec>(config: BootNodeConfig<T>, log: slog::Logger) {
     info!(log, "Contact information"; "enr" => config.local_enr.to_base64());
     info!(log, "Contact information"; "multiaddrs" => format!("{:?}", config.local_enr.multiaddr_p2p()));
 
-    // Build the discv5 server
-
-    // default configuration with packet filtering
-
-    let discv5_config = {
-        let mut builder = Discv5ConfigBuilder::new();
-        if !config.disable_packet_filter {
-            builder.enable_packet_filter();
-        }
-        if !config.auto_update {
-            builder.disable_enr_update();
-        }
-        builder.build()
-    };
-
     // construct the discv5 server
-    let mut discv5 =
-        Discv5::new(config.local_enr.clone(), config.local_key, discv5_config).unwrap();
+    let mut discv5 = Discv5::new(
+        config.local_enr.clone(),
+        config.local_key,
+        config.discv5_config,
+    )
+    .unwrap();
 
     // If there are any bootnodes add them to the routing table
     for enr in config.boot_nodes {