fix(iroh_net): clear the best address on pong timeout only if the pat…

…h is not alive in the timeout period

iroh-net/src/magicsock/node_map/best_addr.rs

@@ -29,6 +29,10 @@ impl BestAddrInner {
             .map(|trust_until| trust_until >= now)
             .unwrap_or(false)
     }
+
+    fn addr(&self) -> SocketAddr {
+        self.addr.addr
+    }
 }
 
 #[derive(Debug)]
@@ -81,49 +85,24 @@ impl BestAddr {
         self.0.is_none()
     }
 
-    pub fn clear(&mut self, reason: ClearReason, has_relay: bool) -> bool {
-        if let Some(addr) = self.addr() {
-            self.0 = None;
-            info!(?reason, ?has_relay, old_addr = %addr, "clearing best_addr");
+    /// Unconditionally clears the best address.
+    pub fn clear(&mut self, reason: ClearReason, has_relay: bool) {
+        let old = self.0.take();
+        if let Some(old_addr) = old.as_ref().map(BestAddrInner::addr) {
+            info!(?reason, ?has_relay, %old_addr, "clearing best_addr");
             // no longer relying on the direct connection
             inc!(MagicsockMetrics, num_direct_conns_removed);
             if has_relay {
                 // we are now relying on the relay connection, add a relay conn
                 inc!(MagicsockMetrics, num_relay_conns_added);
             }
-            true
-        } else {
-            false
-        }
-    }
-
-    pub fn clear_if_equals(
-        &mut self,
-        addr: SocketAddr,
-        reason: ClearReason,
-        has_relay: bool,
-    ) -> bool {
-        match &self.addr() {
-            Some(best_addr) if *best_addr == addr => self.clear(reason, has_relay),
-            _ => false,
         }
     }
 
-    /// Clears best_addr if it equals `addr` and was confirmed before `confirmed_before`.
-    ///
-    /// If the given addr is currently the best address, **and** the best address was
-    /// confirmed longer ago than the provided time, then this clears the best address.
-    pub fn clear_if_addr_older(
-        &mut self,
-        addr: SocketAddr,
-        confirmed_before: Instant,
-        reason: ClearReason,
-        has_relay: bool,
-    ) {
-        if let Some(ref inner) = self.0 {
-            if inner.addr.addr == addr && inner.confirmed_at < confirmed_before {
-                self.clear(reason, has_relay);
-            }
+    /// Clears the best address if equal to `addr`.
+    pub fn clear_if_equals(&mut self, addr: SocketAddr, reason: ClearReason, has_relay: bool) {
+        if self.addr() == Some(addr) {
+            self.clear(reason, has_relay)
         }
     }
 
@@ -221,7 +200,7 @@ impl BestAddr {
     }
 
     pub fn addr(&self) -> Option<SocketAddr> {
-        self.0.as_ref().map(|a| a.addr.addr)
+        self.0.as_ref().map(BestAddrInner::addr)
     }
 }
 

iroh-net/src/magicsock/node_map/node_state.rs

@@ -34,7 +34,7 @@ use super::IpPort;
 /// See [`NodeState::prune_direct_addresses`].
 pub(super) const MAX_INACTIVE_DIRECT_ADDRESSES: usize = 20;
 
-/// How long since an endpoint path was last active before it might be pruned.
+/// How long since an endpoint path was last alive before it might be pruned.
 const LAST_ALIVE_PRUNE_DURATION: Duration = Duration::from_secs(120);
 
 /// How long we wait for a pong reply before assuming it's never coming.
@@ -410,15 +410,28 @@ impl NodeState {
                 SendAddr::Udp(addr) => {
                     if let Some(path_state) = self.direct_addr_state.get_mut(&addr.into()) {
                         path_state.last_ping = None;
+                        // only clear the best address if there was no sign of life from this path
+                        // within the time the pong should have arrived
+                        let consider_alive = path_state
+                            .last_alive()
+                            .map(|last_alive| last_alive.elapsed() <= PING_TIMEOUT_DURATION)
+                            .unwrap_or(false);
+                        if !consider_alive {
+                            self.best_addr.clear_if_equals(
+                                addr,
+                                ClearReason::PongTimeout,
+                                self.relay_url().is_some(),
+                            )
+                        }
+                    } else {
+                        // If we have no state for the best addr it should have been cleared
+                        // anyway.
+                        self.best_addr.clear_if_equals(
+                            addr,
+                            ClearReason::PongTimeout,
+                            self.relay_url.is_some(),
+                        );
                     }
-
-                    // If we fail to ping our current best addr, it is not that good anymore.
-                    self.best_addr.clear_if_addr_older(
-                        addr,
-                        sp.at,
-                        ClearReason::PongTimeout,
-                        self.relay_url.is_some(),
-                    );
                 }
                 SendAddr::Relay(ref url) => {
                     if let Some((home_relay, relay_state)) = self.relay_url.as_mut() {
@@ -1151,10 +1164,10 @@ impl PathState {
 
     /// Check whether this path is considered active.
     ///
-    /// Active means the path has received payload messages within the lat
+    /// Active means the path has received payload messages within the last
     /// [`SESSION_ACTIVE_TIMEOUT`].
     ///
-    /// Note that an endpoint might be alive but not active if it's contactable but not in
+    /// Note that a path might be alive but not active if it's contactable but not in
     /// use.
     pub(super) fn is_active(&self) -> bool {
         self.last_payload_msg