feat(beacon_node): add explicit peers to GossipSub, mark as trusted

beacon_node/lighthouse_network/src/service/mod.rs

@@ -144,6 +144,21 @@ impl<AppReqId: ReqId, TSpec: EthSpec> Network<AppReqId, TSpec> {
         // initialise the node's ID
         let local_keypair = utils::load_private_key(&config, &log);
 
+        let mut trusted_peers: Vec<PeerId> = config
+            .trusted_peers
+            .iter()
+            .map(|x| PeerId::from(x.clone()))
+            .collect();
+
+        // Explicit peers should also be marked as trusted since they are exempt from peer scoring.
+        // Cfr. https://github.com/libp2p/specs/blob/master/pubsub/gossipsub/gossipsub-v1.1.md#explicit-peering-agreements
+        trusted_peers.extend(
+            config
+                .explicit_peers
+                .iter()
+                .map(|x| PeerId::from(x.clone())),
+        );
+
         // set up a collection of variables accessible outside of the network crate
         let network_globals = {
             // Create an ENR or load from disk if appropriate
@@ -158,11 +173,7 @@ impl<AppReqId: ReqId, TSpec: EthSpec> Network<AppReqId, TSpec> {
             let globals = NetworkGlobals::new(
                 enr,
                 meta_data,
-                config
-                    .trusted_peers
-                    .iter()
-                    .map(|x| PeerId::from(x.clone()))
-                    .collect(),
+                trusted_peers,
                 config.disable_peer_scoring,
                 &log,
             );
@@ -275,6 +286,11 @@ impl<AppReqId: ReqId, TSpec: EthSpec> Network<AppReqId, TSpec> {
                 .with_peer_score(params, thresholds)
                 .expect("Valid score params and thresholds");
 
+            // Add explicit peers to GossipSub
+            for explicit_peer in config.explicit_peers.iter() {
+                gossipsub.add_explicit_peer(&PeerId::from(explicit_peer.clone()));
+            }
+
             (gossipsub, update_gossipsub_scores)
         };