feat: get list of ConnectionInfos or an individual node's `Connecti…

…onInfo` (#1435)

## Description

Display connection information for all nodes we have connected with or
have supplied our node with addresses for.

Display connection information on a particular node, using its node id.

## Change checklist

- [x] Self-review.
- [x] Documentation updates if relevant.

iroh-net/src/magic_endpoint.rs

@@ -20,6 +20,8 @@ use crate::{
     tls,
 };
 
+pub use super::magicsock::EndpointInfo as ConnectionInfo;
+
 /// Builder for [MagicEndpoint]
 #[derive(Debug)]
 pub struct MagicEndpointBuilder {
@@ -287,6 +289,31 @@ impl MagicEndpoint {
         self.msock.my_derp().await
     }
 
+    /// Get information on all the nodes we have connection information about.
+    ///
+    /// Includes the node's [`PublicKey`], potential DERP region, its addresses with any known
+    /// latency, and its [`crate::magicsock::ConnectionType`], which let's us know if we are
+    /// currently communicating with that node over a `Direct` (UDP) or `Relay` (DERP) connection.
+    ///
+    /// Connections are currently only pruned on user action (when we explicitly add a new address
+    /// to the internal [`crate::netmap::NetworkMap`] in [`MagicEndpoint::add_known_addrs`]), so
+    /// these connections are not necessarily active connections.
+    pub async fn connection_infos(&self) -> anyhow::Result<Vec<ConnectionInfo>> {
+        self.msock.tracked_endpoints().await
+    }
+
+    /// Get connection information about a specific node.
+    ///
+    /// Includes the node's [`PublicKey`], potential DERP region, its addresses with any known
+    /// latency, and its [`crate::magicsock::ConnectionType`], which let's us know if we are
+    /// currently communicating with that node over a `Direct` (UDP) or `Relay` (DERP) connection.
+    pub async fn connection_info(
+        &self,
+        node_id: PublicKey,
+    ) -> anyhow::Result<Option<ConnectionInfo>> {
+        self.msock.tracked_endpoint(node_id).await
+    }
+
     /// Connect to a remote endpoint.
     ///
     /// The PublicKey and the ALPN protocol are required. If you happen to know dialable addresses of
@@ -346,6 +373,9 @@ impl MagicEndpoint {
     /// This updates the magic socket's *netmap* with these addresses, which are used as candidates
     /// when connecting to this peer (in addition to addresses obtained from a derp server).
     ///
+    /// Note: updating the magic socket's *netmap* will also prune any connections that are *not*
+    /// present in the netmap.
+    ///
     /// If no UDP addresses are added, and `derp_region` is `None`, it will error.
     /// If no UDP addresses are added, and the given `derp_region` cannot be dialed, it will error.
     pub async fn add_known_addrs(

iroh-net/src/magicsock.rs

@@ -68,6 +68,7 @@ mod rebinding_conn;
 mod timer;
 mod udp_actor;
 
+pub use self::endpoint::ConnectionType;
 pub use self::endpoint::EndpointInfo;
 pub use self::metrics::Metrics;
 pub use self::timer::Timer;
@@ -445,7 +446,7 @@ impl MagicSock {
         Ok(c)
     }
 
-    /// Retrieve information about known peers' endpoints in the network.
+    /// Retrieve connection information about nodes in the network.
     pub async fn tracked_endpoints(&self) -> Result<Vec<EndpointInfo>> {
         let (s, r) = sync::oneshot::channel();
         self.inner
@@ -456,6 +457,16 @@ impl MagicSock {
         Ok(res)
     }
 
+    /// Retrieve connection information about a node in the network.
+    pub async fn tracked_endpoint(&self, node_key: PublicKey) -> Result<Option<EndpointInfo>> {
+        let (s, r) = sync::oneshot::channel();
+        self.inner
+            .actor_sender
+            .send(ActorMessage::TrackedEndpoint(node_key, s))
+            .await?;
+        let res = r.await?;
+        Ok(res)
+    }
     /// Query for the local endpoints discovered during the last endpoint discovery.
     pub async fn local_endpoints(&self) -> Result<Vec<config::Endpoint>> {
         let (s, r) = sync::oneshot::channel();
@@ -831,6 +842,7 @@ impl Drop for WgGuard {
 #[allow(clippy::large_enum_variant)]
 enum ActorMessage {
     TrackedEndpoints(sync::oneshot::Sender<Vec<EndpointInfo>>),
+    TrackedEndpoint(PublicKey, sync::oneshot::Sender<Option<EndpointInfo>>),
     LocalEndpoints(sync::oneshot::Sender<Vec<config::Endpoint>>),
     GetMappingAddr(PublicKey, sync::oneshot::Sender<Option<QuicMappedAddr>>),
     SetPreferredPort(u16, sync::oneshot::Sender<()>),
@@ -839,7 +851,7 @@ enum ActorMessage {
     CloseOrReconnect(u16, &'static str),
     ReStun(&'static str),
     EnqueueCallMeMaybe {
-        derp_addr: u16,
+        derp_region: u16,
         endpoint_id: usize,
     },
     SendDiscoMessage {
@@ -981,9 +993,12 @@ impl Actor {
     async fn handle_actor_message(&mut self, msg: ActorMessage) -> bool {
         match msg {
             ActorMessage::TrackedEndpoints(s) => {
-                let eps: Vec<_> = self.peer_map.endpoints().map(|(_, ep)| ep.info()).collect();
+                let eps: Vec<_> = self.peer_map.endpoint_infos();
                 let _ = s.send(eps);
             }
+            ActorMessage::TrackedEndpoint(node_key, s) => {
+                let _ = s.send(self.peer_map.endpoint_info(&node_key));
+            }
             ActorMessage::LocalEndpoints(s) => {
                 let eps: Vec<_> = self.last_endpoints.clone();
                 let _ = s.send(eps);
@@ -1028,10 +1043,10 @@ impl Actor {
                 self.re_stun(reason).await;
             }
             ActorMessage::EnqueueCallMeMaybe {
-                derp_addr,
+                derp_region,
                 endpoint_id,
             } => {
-                self.enqueue_call_me_maybe(derp_addr, endpoint_id).await;
+                self.enqueue_call_me_maybe(derp_region, endpoint_id).await;
             }
             ActorMessage::RebindAll(s) => {
                 self.rebind_all().await;
@@ -1135,8 +1150,8 @@ impl Actor {
 
         let ep_quic_mapped_addr = match self.peer_map.endpoint_for_node_key_mut(&dm.src) {
             Some(ep) => {
-                if ep.derp_addr().is_none() {
-                    ep.add_derp_addr(region_id);
+                if ep.derp_region().is_none() {
+                    ep.add_derp_region(region_id);
                 }
                 ep.quic_mapped_addr
             }
@@ -1146,7 +1161,7 @@ impl Actor {
                     msock_sender: self.inner.actor_sender.clone(),
                     msock_public_key: self.inner.public_key(),
                     public_key: dm.src,
-                    derp_addr: Some(region_id),
+                    derp_region: Some(region_id),
                 });
                 self.peer_map.set_endpoint_for_ip_port(&ipp, id);
                 let ep = self.peer_map.by_id_mut(&id).expect("inserted");
@@ -1252,16 +1267,16 @@ impl Actor {
                 );
 
                 match ep.get_send_addrs().await {
-                    Ok((Some(udp_addr), Some(derp_addr))) => {
+                    Ok((Some(udp_addr), Some(derp_region))) => {
                         let res = self.send_raw(udp_addr, transmits.clone()).await;
-                        self.send_derp(derp_addr, public_key, Self::split_packets(transmits));
+                        self.send_derp(derp_region, public_key, Self::split_packets(transmits));
 
                         if let Err(err) = res {
                             warn!("failed to send UDP: {:?}", err);
                         }
                     }
-                    Ok((None, Some(derp_addr))) => {
-                        self.send_derp(derp_addr, public_key, Self::split_packets(transmits));
+                    Ok((None, Some(derp_region))) => {
+                        self.send_derp(derp_region, public_key, Self::split_packets(transmits));
                     }
                     Ok((Some(udp_addr), None)) => {
                         if let Err(err) = self.send_raw(udp_addr, transmits).await {
@@ -1710,12 +1725,12 @@ impl Actor {
     }
 
     #[instrument(skip_all, fields(self.name = %self.inner.name))]
-    async fn enqueue_call_me_maybe(&mut self, derp_addr: u16, endpoint_id: usize) {
+    async fn enqueue_call_me_maybe(&mut self, derp_region: u16, endpoint_id: usize) {
         let endpoint = self.peer_map.by_id(&endpoint_id);
         if endpoint.is_none() {
             warn!(
                 "enqueue_call_me_maybe with invalid endpoint_id called: {} - {}",
-                derp_addr, endpoint_id
+                derp_region, endpoint_id
             );
             return;
         }
@@ -1738,7 +1753,7 @@ impl Actor {
                         info!("STUN done; sending call-me-maybe",);
                         msg_sender
                             .send(ActorMessage::EnqueueCallMeMaybe {
-                                derp_addr,
+                                derp_region,
                                 endpoint_id,
                             })
                             .await
@@ -1761,13 +1776,13 @@ impl Actor {
                 warn!("sending call me maybe to {public_key:?}");
                 if let Err(err) = msg_sender
                     .send(ActorMessage::SendDiscoMessage {
-                        dst: SendAddr::Derp(derp_addr),
+                        dst: SendAddr::Derp(derp_region),
                         dst_key: public_key,
                         msg,
                     })
                     .await
                 {
-                    warn!("failed to send disco message to {}: {:?}", derp_addr, err);
+                    warn!("failed to send disco message to {}: {:?}", derp_region, err);
                 }
             });
         }
@@ -2049,7 +2064,7 @@ impl Actor {
                         msock_sender: self.inner.actor_sender.clone(),
                         msock_public_key: self.inner.public_key(),
                         public_key: sender,
-                        derp_addr: src.derp_region(),
+                        derp_region: src.derp_region(),
                     });
                 }
                 self.handle_ping(ping, &sender, src, derp_node_src).await;
@@ -2215,7 +2230,7 @@ impl Actor {
                     msock_sender: self.inner.actor_sender.clone(),
                     msock_public_key: self.inner.public_key(),
                     public_key: n.key,
-                    derp_addr: n.derp,
+                    derp_region: n.derp,
                 });
             }