Silky smooth discovery (#1274)

* Initial structural re-write

* Improving discovery update and correcting attestation service logic

* Rework discovery.mod

* Handling lifetimes of query futures

* Discovery update first draft

* format fixes

* Stabalise discv5 update

* Formatting corrections

* Limit FindPeers queries and bug correction

* Update to stable release discv5

* Remove unnecessary pin

* formatting

beacon_node/eth2_libp2p/src/peer_manager/client.rs

@@ -0,0 +1,151 @@
+//! Known Ethereum 2.0 clients and their fingerprints.
+//!
+//! Currently using identify to fingerprint.
+
+use libp2p::identify::IdentifyInfo;
+use serde::Serialize;
+
+/// Various client and protocol information related to a node.
+#[derive(Clone, Debug, Serialize)]
+pub struct Client {
+    /// The client's name (Ex: lighthouse, prism, nimbus, etc)
+    pub kind: ClientKind,
+    /// The client's version.
+    pub version: String,
+    /// The OS version of the client.
+    pub os_version: String,
+    /// The libp2p protocol version.
+    pub protocol_version: String,
+    /// Identify agent string
+    pub agent_string: Option<String>,
+}
+
+#[derive(Clone, Debug, Serialize)]
+pub enum ClientKind {
+    /// A lighthouse node (the best kind).
+    Lighthouse,
+    /// A Nimbus node.
+    Nimbus,
+    /// A Teku node.
+    Teku,
+    /// A Prysm node.
+    Prysm,
+    /// An unknown client.
+    Unknown,
+}
+
+impl Default for Client {
+    fn default() -> Self {
+        Client {
+            kind: ClientKind::Unknown,
+            version: "unknown".into(),
+            os_version: "unknown".into(),
+            protocol_version: "unknown".into(),
+            agent_string: None,
+        }
+    }
+}
+
+impl Client {
+    /// Builds a `Client` from `IdentifyInfo`.
+    pub fn from_identify_info(info: &IdentifyInfo) -> Self {
+        let (kind, version, os_version) = client_from_agent_version(&info.agent_version);
+
+        Client {
+            kind,
+            version,
+            os_version,
+            protocol_version: info.protocol_version.clone(),
+            agent_string: Some(info.agent_version.clone()),
+        }
+    }
+}
+
+impl std::fmt::Display for Client {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self.kind {
+            ClientKind::Lighthouse => write!(
+                f,
+                "Lighthouse: version: {}, os_version: {}",
+                self.version, self.os_version
+            ),
+            ClientKind::Teku => write!(
+                f,
+                "Teku: version: {}, os_version: {}",
+                self.version, self.os_version
+            ),
+            ClientKind::Nimbus => write!(
+                f,
+                "Nimbus: version: {}, os_version: {}",
+                self.version, self.os_version
+            ),
+            ClientKind::Prysm => write!(
+                f,
+                "Prysm: version: {}, os_version: {}",
+                self.version, self.os_version
+            ),
+            ClientKind::Unknown => {
+                if let Some(agent_string) = &self.agent_string {
+                    write!(f, "Unknown: {}", agent_string)
+                } else {
+                    write!(f, "Unknown")
+                }
+            }
+        }
+    }
+}
+
+// helper function to identify clients from their agent_version. Returns the client
+// kind and it's associated version and the OS kind.
+fn client_from_agent_version(agent_version: &str) -> (ClientKind, String, String) {
+    let mut agent_split = agent_version.split('/');
+    match agent_split.next() {
+        Some("Lighthouse") => {
+            let kind = ClientKind::Lighthouse;
+            let mut version = String::from("unknown");
+            let mut os_version = version.clone();
+            if let Some(agent_version) = agent_split.next() {
+                version = agent_version.into();
+                if let Some(agent_os_version) = agent_split.next() {
+                    os_version = agent_os_version.into();
+                }
+            }
+            (kind, version, os_version)
+        }
+        Some("teku") => {
+            let kind = ClientKind::Teku;
+            let mut version = String::from("unknown");
+            let mut os_version = version.clone();
+            if agent_split.next().is_some() {
+                if let Some(agent_version) = agent_split.next() {
+                    version = agent_version.into();
+                    if let Some(agent_os_version) = agent_split.next() {
+                        os_version = agent_os_version.into();
+                    }
+                }
+            }
+            (kind, version, os_version)
+        }
+        Some("github.com") => {
+            let kind = ClientKind::Prysm;
+            let unknown = String::from("unknown");
+            (kind, unknown.clone(), unknown)
+        }
+        Some("nim-libp2p") => {
+            let kind = ClientKind::Nimbus;
+            let mut version = String::from("unknown");
+            let mut os_version = version.clone();
+            if let Some(agent_version) = agent_split.next() {
+                version = agent_version.into();
+                if let Some(agent_os_version) = agent_split.next() {
+                    os_version = agent_os_version.into();
+                }
+            }
+            (kind, version, os_version)
+        }
+        _ => {
+            let unknown = String::from("unknown");
+            (ClientKind::Unknown, unknown.clone(), unknown)
+        }
+    }
+}