feat(stereo): 新增不同型号的小爱音箱组立体声应用

examples/stereo/src/net/discovery.rs

@@ -0,0 +1,45 @@
+use crate::net::protocol::ControlPacket;
+use anyhow::Result;
+use std::net::{IpAddr, SocketAddr};
+use std::time::Duration;
+use tokio::net::UdpSocket;
+
+pub const DISCOVERY_PORT: u16 = 53530;
+
+/// 服务发现模块，用于主从节点的自动发现
+pub struct Discovery;
+
+impl Discovery {
+    /// 主节点：启动广播，告知从节点自己的 TCP 端口
+    pub async fn start_broadcast(tcp_port: u16) -> Result<()> {
+        let socket = UdpSocket::bind("0.0.0.0:0").await?;
+        socket.set_broadcast(true)?;
+
+        let target: SocketAddr = format!("255.255.255.255:{}", DISCOVERY_PORT).parse()?;
+        let msg = postcard::to_allocvec(&ControlPacket::ServerHello { udp_port: tcp_port })?;
+
+        tokio::spawn(async move {
+            loop {
+                let _ = socket.send_to(&msg, target).await;
+                tokio::time::sleep(Duration::from_secs(1)).await;
+            }
+        });
+
+        Ok(())
+    }
+
+    /// 从节点：监听广播，发现主节点的 IP 和 TCP 端口
+    pub async fn discover_master() -> Result<(IpAddr, u16)> {
+        let socket = UdpSocket::bind(format!("0.0.0.0:{}", DISCOVERY_PORT)).await?;
+        let mut buf = [0u8; 1024];
+
+        loop {
+            let (len, addr) = socket.recv_from(&mut buf).await?;
+            if let Ok(ControlPacket::ServerHello { udp_port }) =
+                postcard::from_bytes::<ControlPacket>(&buf[..len])
+            {
+                return Ok((addr.ip(), udp_port));
+            }
+        }
+    }
+}