send SSDP NOTIFY in parallel

Cargo.lock

@@ -1649,6 +1649,7 @@ dependencies = [
  "anyhow",
  "axum",
  "bstr",
+ "futures",
  "gethostname",
  "http",
  "httparse",

crates/upnp-serve/Cargo.toml

@@ -35,6 +35,7 @@ reqwest = { version = "0.12.7", default-features = false }
 socket2 = "0.5.7"
 quick-xml = { version = "0.36.1", features = ["serialize"] }
 network-interface = "2.0.0"
+futures = "0.3.30"
 
 [dev-dependencies]
 tracing-subscriber = "0.3.18"

crates/upnp-serve/src/ssdp.rs

@@ -133,7 +133,7 @@ impl SsdpRunner {
         Ok(Self { opts, socket })
     }
 
-    fn generate_notify_message(&self, kind: &str, nts: &str, location: &str) -> String {
+    fn generate_notify_message(&self, kind: &str, nts: &str, location: &url::Url) -> String {
         let usn: &str = &self.opts.usn;
         let server: &str = &self.opts.server_string;
         let bcast_addr = UPNP_BROADCAST_ADDR;
@@ -187,35 +187,51 @@ Content-Length: 0\r\n\r\n"
             }
         };
 
-        for ni in interfaces {
-            for niaddr in ni.addr {
-                let ip = niaddr.ip();
-                if ip.is_ipv6() || ip.is_loopback() {
-                    continue;
+        let futs = interfaces
+            .into_iter()
+            .flat_map(|ni| ni.addr)
+            .filter_map(|addr| {
+                let ip = addr.ip();
+                if ip.is_ipv4() && !ip.is_loopback() {
+                    Some(ip)
+                } else {
+                    None
                 }
+            })
+            .map(|ip| async move {
                 let addr = SocketAddr::new(ip, 0);
                 let sock = match tokio::net::UdpSocket::bind(addr).await {
                     Ok(sock) => sock,
                     Err(e) => {
                         debug!(%addr, error=?e, "error binding UDP to send NOTIFY");
-                        continue;
+                        return;
                     }
                 };
 
                 let mut location = self.opts.description_http_location.clone();
                 location.set_host(Some(&format!("{ip}"))).unwrap();
 
-                for kind in [UPNP_KIND_ROOT_DEVICE, UPNP_KIND_MEDIASERVER] {
-                    let msg = self.generate_notify_message(kind, nts, &format!("{location}"));
-                    trace!(content=?msg, addr=?UPNP_BROADCAST_ADDR, "sending SSDP NOTIFY");
-                    if let Err(e) = sock.send_to(msg.as_bytes(), UPNP_BROADCAST_ADDR).await {
-                        debug!(sock_addr=%addr, error=%e, kind, nts, "error sending SSDP NOTIFY")
-                    } else {
-                        debug!(kind, nts, %location, "sent SSDP NOTIFY")
+                macro_rules! gen {
+                    ($kind:expr) => {
+                        async {
+                            let msg = self.generate_notify_message($kind, nts, &location);
+                            trace!(content=?msg, addr=?UPNP_BROADCAST_ADDR, "sending SSDP NOTIFY");
+                            if let Err(e) = sock.send_to(msg.as_bytes(), UPNP_BROADCAST_ADDR).await {
+                                debug!(sock_addr=%addr, error=%e, kind=$kind, nts, "error sending SSDP NOTIFY")
+                            } else {
+                                debug!(kind=$kind, nts, %location, "sent SSDP NOTIFY")
+                            }
+                        }
                     }
                 }
-            }
-        }
+
+                let f1 = gen!(UPNP_KIND_ROOT_DEVICE);
+                let f2 = gen!(UPNP_KIND_MEDIASERVER) ;
+
+                tokio::join!(f1, f2);
+            });
+
+        futures::future::join_all(futs).await;
     }
 
     async fn task_send_alive_notifies_periodically(&self) -> anyhow::Result<()> {