Add logging for ephemeral peer negotiation timeouts on Windows

talpid-wireguard/src/lib.rs

@@ -268,14 +268,22 @@ impl WireguardMonitor {
 
             let ephemeral_obfs_sender = close_obfs_sender.clone();
             if config.quantum_resistant || config.daita {
-                ephemeral::config_ephemeral_peers(
+                if let Err(e) = ephemeral::config_ephemeral_peers(
                     &tunnel,
                     &mut config,
                     args.retry_attempt,
                     obfuscator.clone(),
                     ephemeral_obfs_sender,
                 )
-                .await?;
+                .await
+                {
+                    // We have received a small amount of reports about ephemeral peer nogationation
+                    // timing out on Windows for 2024.9-beta1. These verbose data usage logs are
+                    // a temporary measure to help us understand the issue. They can be removed
+                    // if the issue is resolved.
+                    log_tunnel_data_usage(&config, &tunnel).await;
+                    return Err(e);
+                }
 
                 let metadata = Self::tunnel_metadata(&iface_name, &config);
                 event_hook
@@ -965,6 +973,25 @@ impl WireguardMonitor {
     }
 }
 
+async fn log_tunnel_data_usage(config: &Config, tunnel: &Arc<AsyncMutex<Option<Box<dyn Tunnel>>>>) {
+    let tunnel = tunnel.lock().await;
+    let Ok(tunnel_stats) = tunnel.as_ref().unwrap().get_tunnel_stats() else {
+        return;
+    };
+    if let Some(stats) = config
+        .exit_peer
+        .as_ref()
+        .map(|peer| peer.public_key.as_bytes())
+        .and_then(|pubkey| tunnel_stats.get(pubkey))
+    {
+        log::warn!("Exit peer stats: {:?}", stats);
+    };
+    let pubkey = config.entry_peer.public_key.as_bytes();
+    if let Some(stats) = tunnel_stats.get(pubkey) {
+        log::warn!("Entry peer stats: {:?}", stats);
+    }
+}
+
 #[derive(Debug)]
 enum CloseMsg {
     Stop,