Add --wait flag and ip link debug output

- Add --wait / -w command-line flag for debugger attachment
- When --wait is set, daemon blocks after init with thread::park()
- Add ip link show output after TUN device creation for debugging

src/bin/fips.rs

@@ -6,8 +6,13 @@ use fips::{Config, Node};
 use tracing::{error, info, warn, Level};
 use tracing_subscriber::{fmt, EnvFilter};
 
+fn parse_args() -> bool {
+    std::env::args().any(|arg| arg == "--wait" || arg == "-w")
+}
+
 #[tokio::main(flavor = "current_thread")]
 async fn main() {
+    let wait_mode = parse_args();
     // Initialize logging
     let filter = EnvFilter::builder()
         .with_default_directive(Level::INFO.into())
@@ -87,6 +92,22 @@ async fn main() {
                     address = %device.address(),
                     "TUN device active"
                 );
+
+                // Show interface details for debugging
+                let output = std::process::Command::new("ip")
+                    .args(["link", "show", device.name()])
+                    .output();
+                match output {
+                    Ok(out) => {
+                        if out.status.success() {
+                            info!("ip link show {}:\n{}", device.name(),
+                                String::from_utf8_lossy(&out.stdout));
+                        }
+                    }
+                    Err(e) => {
+                        warn!("Failed to run ip link: {}", e);
+                    }
+                }
             }
             Ok(false) => {
                 info!("TUN disabled");
@@ -101,5 +122,12 @@ async fn main() {
     info!("FIPS initialized successfully");
 
     // TODO: Start event loop, transports, etc.
-    info!("No transports configured, nothing to do");
+    if wait_mode {
+        info!("Running in wait mode (--wait). Press Ctrl+C to exit.");
+        info!("Attach debugger with: sudo ./scripts/lldb-attach-fips.sh");
+        // Block forever (until signal)
+        std::thread::park();
+    } else {
+        info!("No transports configured, nothing to do");
+    }
 }