[omg] GUI, mDNS, list games on client start

crates/lanspread-mdns/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "lanspread-mdns"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+mdns-sd = "0.11"
+eyre = { workspace = true }
+tracing = { workspace = true }

crates/lanspread-mdns/src/lib.rs

@@ -0,0 +1,86 @@
+use std::net::SocketAddr;
+
+use eyre::bail;
+pub use mdns_sd::DaemonEvent;
+use mdns_sd::{Receiver, ServiceDaemon, ServiceEvent, ServiceInfo};
+
+pub const LANSPREAD_SERVICE_TYPE: &str = "_lanspread._udp.local.";
+pub const LANSPREAD_INSTANCE_NAME: &str = "softlan";
+
+pub struct MdnsAdvertiser {
+    daemon: ServiceDaemon,
+    service_info: ServiceInfo,
+    pub monitor: Receiver<DaemonEvent>,
+}
+
+impl MdnsAdvertiser {
+    pub fn new(service_type: &str, instance_name: &str, address: SocketAddr) -> eyre::Result<Self> {
+        let host_name = format!("{}.local.", address.ip());
+        let daemon = ServiceDaemon::new()?;
+        let service_info = ServiceInfo::new(
+            service_type,
+            instance_name,
+            &host_name,
+            address.ip(),
+            address.port(),
+            None,
+        )?;
+
+        let monitor = daemon.monitor()?;
+
+        // Register the service
+        daemon.register(service_info.clone())?;
+
+        Ok(Self {
+            daemon,
+            service_info,
+            monitor,
+        })
+    }
+}
+
+impl Drop for MdnsAdvertiser {
+    fn drop(&mut self) {
+        let _ = self.daemon.unregister(self.service_info.get_fullname());
+        let _ = self.daemon.shutdown();
+    }
+}
+
+pub fn discover_service(
+    service_type: &str,
+    instance_name: Option<&str>,
+) -> eyre::Result<SocketAddr> {
+    let mdns = ServiceDaemon::new().expect("Failed to create mDNS daemon.");
+
+    let receiver = mdns.browse(service_type)?;
+
+    while let Ok(event) = receiver.recv() {
+        match event {
+            ServiceEvent::ServiceResolved(info) => {
+                tracing::trace!(?info, "mdns ServiceResolved event");
+
+                if let Some(instance_name) = instance_name {
+                    if info.get_fullname() != format!("{}.{}", instance_name, service_type) {
+                        tracing::warn!(
+                            "Found service with wrong instance name: {} (expected: {})",
+                            info.get_fullname(),
+                            instance_name,
+                        );
+                        continue;
+                    }
+                }
+
+                if let Some(address) = info.get_addresses().iter().next() {
+                    tracing::info!("Found server at {}:{}", address, info.get_port());
+                    return Ok((*address, info.get_port()).into());
+                }
+
+                tracing::error!(?info, "No address found in mDNS response.");
+            }
+            other_event => {
+                tracing::trace!(?other_event, "mdns unrelated event");
+            }
+        }
+    }
+    bail!("No server found.")
+}