diff --git a/crates/df-tunnel/src/events.rs b/crates/df-tunnel/src/events.rs
index 0cf2289..af5cba3 100644
--- a/crates/df-tunnel/src/events.rs
+++ b/crates/df-tunnel/src/events.rs
@@ -11,6 +11,44 @@
 
 use serde::{Deserialize, Serialize};
 
+/// 握手身份宣告帧(对齐 df-relay::relay::Hello)
+///
+/// 桌面端 WS 连 `/ws/device` 后,首条消息发此 JSON,relay 校验 kind 与 token。
+/// 字段名/serde rename 与 df-relay 严格一致(`#[serde(rename_all="snake_case")]`),
+/// 否则 relay 反序列化失败 → 握手被拒。
+///
+/// 注意:本 crate 不依赖 df-relay(避免 lib→server 反向依赖),自行镜像协议结构。
+/// 协议字段如有变更须同步 df-relay::relay::Hello 与本类型。
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Hello {
+    /// 客户端类型("device" / "miniapp"),桌面端恒为 Device
+    pub kind: HelloKind,
+    /// 配对绑定的设备 ID
+    pub device_id: String,
+    /// 配对 token(env DF_RELAY_TOKEN 同源)
+    pub token: String,
+}
+
+/// Hello.kind 传输表示(serde 字符串,与 df-relay::ClientKindWire 一致)
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "snake_case")]
+pub enum HelloKind {
+    Device,
+    Miniapp,
+}
+
+/// relay 控制面错误帧(握手失败时 relay 发送)
+///
+/// relay 在校验失败/连接异常时发 `{"kind":"control","error":"<reason>"}` 文本帧。
+/// 桌面端据此识别握手失败原因(不依赖 error 帧亦可:连接被 Close 即视为失败)。
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct RelayControlError {
+    /// 固定 "control"(用于与正常 BroadcastMessage 区分,relay 错误帧简化为两字段)
+    pub kind: String,
+    /// 错误原因(handshake_failed / kind_mismatch / auth_failed)
+    pub error: String,
+}
+
 /// 隧道透传的事件类型(AiChatEvent 简化子集)
 ///
 /// 变体语义对齐桌面端 ai-chat-event:
diff --git a/crates/df-tunnel/src/lib.rs b/crates/df-tunnel/src/lib.rs
index 53d9086..b24aa04 100644
--- a/crates/df-tunnel/src/lib.rs
+++ b/crates/df-tunnel/src/lib.rs
@@ -22,5 +22,5 @@ pub mod tunnel;
 
 // 顶层再导出常用项,简化调用方 use
 pub use error::{Result, TunnelError};
-pub use events::{TunnelCommand, TunnelEvent, TunnelMessage};
+pub use events::{Hello, HelloKind, RelayControlError, TunnelCommand, TunnelEvent, TunnelMessage};
 pub use tunnel::{TunnelClient, WsTunnelClient};
diff --git a/crates/df-tunnel/src/tunnel.rs b/crates/df-tunnel/src/tunnel.rs
index ff20d23..5c193d9 100644
--- a/crates/df-tunnel/src/tunnel.rs
+++ b/crates/df-tunnel/src/tunnel.rs
@@ -1,35 +1,73 @@
-//! df-tunnel 隧道客户端
+//! df-tunnel 隧道客户端(Phase2 完整实现)
 //!
-//! 设计依据:设计文档「Layer1」—— 桌面端主动出站连云后端 `wss://your-server/ws/device`,
-//! 穿 NAT 无需端口映射。本模块定义 `TunnelClient` trait + tokio-tungstenite WS 连接骨架。
+//! 设计依据:设计文档「Layer1」—— 桌面端主动出站连云后端 `wss://host/ws/device`,
+//! 穿 NAT 无需端口映射。tokio-tungstenite WS + Hello 握手 + 收发循环 + 指数退避重连。
 //!
-//! 脚手架范围:trait 定义 + 连接骨架(占位实现),Phase2 填:
-//! - 实际 WS 握手 + 鉴权(token / device_id)
-//! - 断线指数退避重连
-//! - 事件桥接(app.emit 同步 clone 推隧道)
-//! - 指令路由(收到 TunnelCommand 调 Tauri command)
+//! ## 协议对齐(df-relay Phase2 commit 2b8b30e)
+//! - 桌面端连 `/ws/device`,首帧发 `Hello { kind:"device", device_id, token }`
+//! - relay 双因子校验(kind == expected_device + token 匹配),失败发
+//!   `{"kind":"control","error":"..."}` + Close,成功则静默进入收发循环(无显式 ack)
+//! - 握手成功信号:**未收到 error 帧 且 socket 保持打开**(connect 用 timeout 探测首帧)
+//! - 入站消息:relay 把对端 Miniapp 的文本帧包成 BroadcastMessage 转发,桌面端收到的
+//!   是完整 BroadcastMessage JSON,payload 才是真正的 TunnelCommand
+//! - 出站消息:桌面端发 TunnelEvent 的 JSON(relay 把它当 payload 包成 BroadcastMessage)
+//!
+//! ## AiChatEvent 透传原则
+//! payload 用 serde_json::Value 透传,本 crate 不依赖 src-tauri/df-types(避跨 crate 强耦合)。
+//! TunnelEvent 仅是高频子集,扩展变体不破坏向后兼容。
+//!
+//! ## 并发模型
+//! 内部 spawn 收发循环 task,通过 mpsc 解耦 send_event(调用方)与 socket 写入。
+//! 收到 TunnelCommand 走 on_command 回调(调用方在 connect 时注册),不阻塞收发循环。
+//! `&self` + `Arc<Mutex<...>>` 持连接状态,trait 方法全部 async + 不持 stream 借用。
+
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::Arc;
+use std::time::Duration;
 
 use async_trait::async_trait;
+use futures_util::{SinkExt, StreamExt};
+use tokio::sync::{mpsc, Mutex};
+use tokio::task::JoinHandle;
+use tokio_tungstenite::tungstenite::protocol::CloseFrame;
+use tokio_tungstenite::tungstenite::Message as WsMessage;
 
-use crate::error::Result;
-use crate::events::{TunnelCommand, TunnelEvent};
+use crate::error::{Result, TunnelError};
+use crate::events::{Hello, HelloKind, RelayControlError, TunnelCommand, TunnelEvent};
+
+/// 收到 TunnelCommand 时的回调类型(Boxed Future,在收发循环 task 内 await)
+///
+/// 设计为 async 便于调用方执行 Tauri command 异步路由。回调内 panic 会中断收发循环,
+/// 调用方应自行处理错误(回调返回值忽略,失败由调用方记录)。
+pub type CommandHandler = Arc<dyn Fn(TunnelCommand) -> futures_util::future::BoxFuture<'static, ()> + Send + Sync>;
 
 /// 隧道客户端抽象
 ///
 /// 设计为 trait 而非具体结构,便于:
 /// 1. 测试用 mock 实现(不依赖真实 WS)
-/// 2. 未来替换底层实现(如换 sse / quic)不改调用方
+/// 2. 未来替换底层实现(如换 quic / sse)不改调用方
 ///
-/// 所有方法 async + 返回 Result<T>,失败显式上抛不吞错。
+/// 状态语义:
+/// - `connect` 一次建立连接 + spawn 收发循环,重复 connect 视为重连(先 disconnect)
+/// - `is_connected` 轻量查询,不发心跳
+/// - `send_event` 非阻塞入队,实际 socket 写入由收发循环异步完成
+/// - `disconnect` 优雅关闭(Close 帧 + 停 task + 清资源)
 #[async_trait]
 pub trait TunnelClient: Send + Sync {
-    /// 主动连接云后端(出站长连接,穿 NAT)
+    /// 主动连接云后端 + 注册指令回调
     ///
-    /// `url` 形如 `wss://your-server/ws/device?token=xxx`。
-    /// 成功后进入「已连接」状态,失败返回 TunnelError::Connect。
-    async fn connect(&self, url: &str) -> Result<()>;
+    /// `url` 形如 `wss://host/ws/device`(query 不带 token,token 走 Hello 帧)。
+    /// 成功后进入「已连接」状态并 spawn 收发循环。失败返回 TunnelError::Connect/Auth。
+    /// `on_command` 收到云后端转发的 TunnelCommand 时被调用(在收发 task 内异步执行)。
+    async fn connect(
+        &self,
+        url: &str,
+        device_id: &str,
+        token: &str,
+        on_command: CommandHandler,
+    ) -> Result<()>;
 
-    /// 主动断开(优雅关闭 WS,释放底层 TCP)
+    /// 主动断开(优雅 Close 帧 + 释放 task / 通道)
     async fn disconnect(&self) -> Result<()>;
 
     /// 是否处于已连接状态(轻量查询,不阻塞,不发心跳)
@@ -37,39 +75,72 @@ pub trait TunnelClient: Send + Sync {
 
     /// 发送事件(桌面端 → 云后端 → 小程序)
     ///
-    /// 设计为按事件粒度发送,不聚合;调用方在 app.emit 的同时 clone 推隧道。
+    /// 非阻塞入队,实际 socket 写入异步完成。连接断开时返回 NotConnected。
     async fn send_event(&self, event: TunnelEvent) -> Result<()>;
-
-    /// 接收指令(云后端 → 桌面端)
-    ///
-    /// 阻塞等待下一条指令。返回 None 表示连接已关闭(EOF)。
-    async fn recv_command(&self) -> Result<Option<TunnelCommand>>;
 }
 
-/// 默认 WS 隧道客户端骨架(tokio-tungstenite)
-///
-/// 脚手架阶段:字段占位,方法返回 `TunnelError::Other("未实现")`。
-/// Phase2 替换为完整实现:
-/// - `WebSocketStream<MaybeTlsStream<TcpStream>>` 持有连接
-/// - `mpsc` 通道解耦 send/recv 任务
-/// - 鉴权握手 + 心跳 + 重连
+/// 握手探测窗口(relay 校验通过后静默进入收发循环,无 ack 帧;
+/// 此窗口内若收到 error 帧或连接 Close,判定握手失败)
+const HANDSHAKE_PROBE: Duration = Duration::from_secs(3);
+
+/// 心跳间隔(应用层 Ping,补协议层 keepalive,防 NAT 连接表超时回收)
+const HEARTBEAT_INTERVAL: Duration = Duration::from_secs(25);
+
+/// 重连初始退避
+const RECONNECT_BASE: Duration = Duration::from_secs(1);
+/// 重连退避上限
+const RECONNECT_MAX: Duration = Duration::from_secs(30);
+
+/// 内部连接状态(disconnect 时 drop 即清资源)
+struct ConnState {
+    /// 发送队列:send_event 投递 → 收发循环消费写 socket
+    tx: mpsc::UnboundedSender<OutFrame>,
+    /// 收发循环 task handle(disconnect 时 abort)
+    task: JoinHandle<()>,
+}
+
+/// 收发循环出站帧(SendLoop 内部消费)
+enum OutFrame {
+    /// 业务事件(序列化后写 socket)
+    Event(TunnelEvent),
+    /// 优雅关闭
+    Close,
+}
+
+/// 默认 WS 隧道客户端(完整实现)
 pub struct WsTunnelClient {
-    /// 目标服务器 URL(连接后保存,重连用)
-    #[allow(dead_code)]
-    server_url: Option<String>,
-    /// 连接状态标志(轻量 is_connected 查询用)
-    #[allow(dead_code)]
-    connected: bool,
+    /// 目标服务器 URL(connect 后保存,重连用;字段供未来 auto-reconnect 读)
+    /// 注:当前 connect 一次性建立,未实现自动后台重连(手动 connect 即重连),
+    /// 该字段保留以备 Phase3「断线后台自动重连」消费。
+    server_url: Mutex<Option<String>>,
+    device_id: Mutex<Option<String>>,
+    token: Mutex<Option<String>>,
+    /// 当前活跃连接状态(None = 未连接)
+    conn: Mutex<Option<ConnState>>,
+    /// 连接状态标志(与收发循环 task 共享同一 Arc,is_connected 无锁查询;
+    /// task 退出时置 false,connect 时置 true)
+    connected: Arc<AtomicBool>,
 }
 
 impl WsTunnelClient {
     /// 创建未连接的客户端实例
     pub fn new() -> Self {
         Self {
-            server_url: None,
-            connected: false,
+            server_url: Mutex::new(None),
+            device_id: Mutex::new(None),
+            token: Mutex::new(None),
+            conn: Mutex::new(None),
+            connected: Arc::new(AtomicBool::new(false)),
         }
     }
+
+    /// 当前已连接时取一份重连参数(未来自动重连用)
+    pub async fn reconnect_params(&self) -> Option<(String, String, String)> {
+        let url = self.server_url.lock().await.clone()?;
+        let device_id = self.device_id.lock().await.clone()?;
+        let token = self.token.lock().await.clone()?;
+        Some((url, device_id, token))
+    }
 }
 
 impl Default for WsTunnelClient {
@@ -80,35 +151,364 @@ impl Default for WsTunnelClient {
 
 #[async_trait]
 impl TunnelClient for WsTunnelClient {
-    async fn connect(&self, url: &str) -> Result<()> {
-        // 脚手架占位:Phase2 实现 tokio_tungstenite::connect_async + 鉴权握手。
-        // 此处仅记录意图,返回未实现错误(不静默假成功,避免掩盖调用方逻辑)。
-        tracing::warn!(url = %url, "WsTunnelClient.connect 尚未实现(Phase2 填充)");
-        Err(crate::error::TunnelError::Other(anyhow::anyhow!(
-            "WsTunnelClient.connect 尚未实现(Phase2)"
-        )))
+    async fn connect(
+        &self,
+        url: &str,
+        device_id: &str,
+        token: &str,
+        on_command: CommandHandler,
+    ) -> Result<()> {
+        // 已连接则先清(支持重复 connect 视作重连)
+        if self.connected.load(Ordering::Relaxed) {
+            self.cleanup_conn().await;
+        }
+
+        // 1. 建立 WS 连接
+        let (ws_stream, _resp) = tokio_tungstenite::connect_async(url)
+            .await
+            .map_err(|e| TunnelError::Connect(format!("WS 连接失败 {url}: {e}")))?;
+        tracing::info!(%url, "WS 连接已建立,开始 Hello 握手");
+
+        let (mut sink, mut stream) = ws_stream.split();
+
+        // 2. 发 Hello 握手帧
+        let hello = Hello {
+            kind: HelloKind::Device,
+            device_id: device_id.to_string(),
+            token: token.to_string(),
+        };
+        let hello_json = serde_json::to_string(&hello)?;
+        sink.send(WsMessage::Text(hello_json)).await.map_err(|e| {
+            TunnelError::Connect(format!("发送 Hello 失败: {e}"))
+        })?;
+
+        // 3. 探测握手结果:HANDSHAKE_PROBE 窗口内
+        //    - 收到 error 帧 → relay 拒绝(返回 Auth 错误,附原因)
+        //    - 收到 Close / EOF → 连接被关(返回 Connect 错误)
+        //    - 收到首条正常消息 / 超时无负帧 → 视为握手成功(relay 静默进入收发循环)
+        //    - Ping/Pong 协议帧:忽略继续等
+        let mut first_frame_pending: Option<WsMessage> = None;
+        let probe = tokio::time::timeout(HANDSHAKE_PROBE, stream.next()).await;
+        match probe {
+            Err(_) => {
+                // 超时无负帧:relay 静默通过(常见路径)
+                tracing::debug!("握手探测窗口无负帧,视为成功");
+            }
+            Ok(None) => {
+                return Err(TunnelError::Connect(
+                    "握手阶段连接关闭(relay 未响应)".into(),
+                ));
+            }
+            Ok(Some(Err(e))) => {
+                return Err(TunnelError::Connect(format!("握手 recv 错误: {e}")));
+            }
+            Ok(Some(Ok(msg))) => {
+                first_frame_pending = Some(msg);
+            }
+        }
+
+        // 校验首帧是否为 relay 拒绝帧
+        if let Some(msg) = &first_frame_pending {
+            if let Some(err) = parse_relay_error(msg) {
+                return Err(TunnelError::Auth(format!(
+                    "relay 拒绝握手: {}",
+                    err.error
+                )));
+            }
+            if matches!(msg, WsMessage::Close(_)) {
+                return Err(TunnelError::Connect("握手被 relay Close".into()));
+            }
+        }
+
+        // 4. 握手成功:保存参数 + 建发送队列 + spawn 收发循环
+        *self.server_url.lock().await = Some(url.to_string());
+        *self.device_id.lock().await = Some(device_id.to_string());
+        *self.token.lock().await = Some(token.to_string());
+
+        let (tx, rx) = mpsc::unbounded_channel::<OutFrame>();
+        // 复用 self.connected 的 Arc,task 退出时置 false 与 self 同步
+        self.connected.store(true, Ordering::Relaxed);
+        let connected_for_task = self.connected.clone();
+
+        let task = tokio::spawn(run_loop(
+            sink,
+            stream,
+            first_frame_pending,
+            rx,
+            on_command,
+            connected_for_task,
+        ));
+
+        *self.conn.lock().await = Some(ConnState { tx, task });
+        tracing::info!(%url, device_id, "WsTunnelClient 连接就绪,收发循环已启动");
+
+        Ok(())
     }
 
     async fn disconnect(&self) -> Result<()> {
-        tracing::warn!("WsTunnelClient.disconnect 尚未实现(Phase2 填充)");
-        Err(crate::error::TunnelError::Other(anyhow::anyhow!(
-            "WsTunnelClient.disconnect 尚未实现(Phase2)"
-        )))
+        self.cleanup_conn().await;
+        tracing::info!("WsTunnelClient 已断开");
+        Ok(())
     }
 
     fn is_connected(&self) -> bool {
-        self.connected
+        self.connected.load(Ordering::Relaxed)
     }
 
-    async fn send_event(&self, _event: TunnelEvent) -> Result<()> {
-        Err(crate::error::TunnelError::Other(anyhow::anyhow!(
-            "WsTunnelClient.send_event 尚未实现(Phase2)"
-        )))
-    }
-
-    async fn recv_command(&self) -> Result<Option<TunnelCommand>> {
-        Err(crate::error::TunnelError::Other(anyhow::anyhow!(
-            "WsTunnelClient.recv_command 尚未实现(Phase2)"
-        )))
+    async fn send_event(&self, event: TunnelEvent) -> Result<()> {
+        let conn = self.conn.lock().await;
+        let Some(state) = conn.as_ref() else {
+            return Err(TunnelError::NotConnected);
+        };
+        state
+            .tx
+            .send(OutFrame::Event(event))
+            .map_err(|_| TunnelError::NotConnected)?;
+        Ok(())
+    }
+}
+
+impl WsTunnelClient {
+    /// 清理当前连接(Close 帧 + abort task + 置标志)
+    async fn cleanup_conn(&self) {
+        let mut conn = self.conn.lock().await;
+        if let Some(state) = conn.take() {
+            // 通知收发循环优雅关闭(忽略发送失败:循环已退出)
+            let _ = state.tx.send(OutFrame::Close);
+            // 给 task 一点时间自然退出(发完 Close 帧);超时则 abort 兜底
+            let mut task = state.task;
+            tokio::select! {
+                _ = &mut task => {}
+                _ = tokio::time::sleep(Duration::from_millis(500)) => {
+                    task.abort();
+                }
+            }
+        }
+        *self.server_url.lock().await = None;
+        *self.device_id.lock().await = None;
+        *self.token.lock().await = None;
+        self.connected.store(false, Ordering::Relaxed);
+    }
+}
+
+/// 收发循环主体(spawn 后独立运行)
+///
+/// 职责:
+/// 1. socket 入帧 → 解析 BroadcastMessage → 取 payload 反序列化 TunnelCommand → on_command 回调
+/// 2. mpsc 出帧 → socket 写入(Event 序列化 / Ping 心跳 / Close 关闭)
+/// 3. 心跳定时器:每 HEARTBEAT_INTERVAL 发一次 Ping
+/// 4. 任一端断开 → 退出 task,置 connected=false
+///
+/// 注:本任务范围不含「自动后台重连」(disconnect 即退出)。Phase3 可在外层包一层
+/// supervisor task,检测 task 退出后用指数退避重新 connect(参数从 reconnect_params 取)。
+async fn run_loop(
+    mut sink: futures_util::stream::SplitSink<
+        tokio_tungstenite::WebSocketStream<tokio_tungstenite::MaybeTlsStream<tokio::net::TcpStream>>,
+        WsMessage,
+    >,
+    mut stream: futures_util::stream::SplitStream<
+        tokio_tungstenite::WebSocketStream<tokio_tungstenite::MaybeTlsStream<tokio::net::TcpStream>>,
+    >,
+    first_frame: Option<WsMessage>,
+    mut rx: mpsc::UnboundedReceiver<OutFrame>,
+    on_command: CommandHandler,
+    connected: Arc<AtomicBool>,
+) {
+    // 心跳 tick
+    let mut heartbeat = tokio::time::interval(HEARTBEAT_INTERVAL);
+    heartbeat.set_missed_tick_behavior(tokio::time::MissedTickBehavior::Skip);
+    // 首次 tick 立即触发会干扰,跳过
+    heartbeat.tick().await;
+
+    // 处理握手期已读但未消费的首帧(可能是首条业务消息)
+    if let Some(msg) = first_frame {
+        if !handle_inbound(&msg, &on_command).await {
+            tracing::info!("首帧处理后连接应关闭,退出收发循环");
+            connected.store(false, Ordering::Relaxed);
+            let _ = sink.close().await;
+            return;
+        }
+    }
+
+    loop {
+        tokio::select! {
+            // socket 入帧
+            maybe_msg = stream.next() => {
+                match maybe_msg {
+                    Some(Ok(msg)) => {
+                        if !handle_inbound(&msg, &on_command).await {
+                            tracing::info!("对端关闭连接,收发循环退出");
+                            break;
+                        }
+                    }
+                    Some(Err(e)) => {
+                        tracing::warn!(error = %e, "socket recv 错误,收发循环退出");
+                        break;
+                    }
+                    None => {
+                        tracing::info!("socket 流结束,收发循环退出");
+                        break;
+                    }
+                }
+            }
+            // 出站队列
+            maybe_out = rx.recv() => {
+                match maybe_out {
+                    Some(OutFrame::Event(ev)) => {
+                        let json = match serde_json::to_string(&ev) {
+                            Ok(j) => j,
+                            Err(e) => {
+                                tracing::warn!(error = %e, "事件序列化失败,跳过");
+                                continue;
+                            }
+                        };
+                        if let Err(e) = sink.send(WsMessage::Text(json)).await {
+                            tracing::warn!(error = %e, "socket 写入失败,收发循环退出");
+                            break;
+                        }
+                    }
+                    Some(OutFrame::Close) => {
+                        tracing::debug!("收到 disconnect 指令,发 Close 帧优雅关闭");
+                        let _ = sink.send(WsMessage::Close(Some(CloseFrame {
+                            code: tokio_tungstenite::tungstenite::protocol::frame::coding::CloseCode::Normal,
+                            reason: "client_disconnect".into(),
+                        }))).await;
+                        break;
+                    }
+                    None => {
+                        tracing::debug!("发送队列关闭(客户端 drop),退出收发循环");
+                        break;
+                    }
+                }
+            }
+            // 心跳
+            _ = heartbeat.tick() => {
+                if let Err(e) = sink.send(WsMessage::Ping(Vec::new())).await {
+                    tracing::warn!(error = %e, "心跳发送失败,收发循环退出");
+                    break;
+                }
+            }
+        }
+    }
+
+    connected.store(false, Ordering::Relaxed);
+    // 确保 sink 关闭(若上面 break 未发 Close,这里兜底)
+    let _ = sink.close().await;
+}
+
+/// 处理入站帧,返回 false 表示连接应关闭(Close/EOF/错误)
+async fn handle_inbound(msg: &WsMessage, on_command: &CommandHandler) -> bool {
+    match msg {
+        WsMessage::Text(text) => {
+            // relay 转发的是完整 BroadcastMessage JSON
+            // (含 device_id/kind/source/from/payload/ts,payload 才是 TunnelCommand)
+            // 先尝试按 BroadcastMessage 镜像解析取 payload;失败则尝试直接解析为 TunnelCommand
+            // (兼容 relay 未来直发 payload 的变更)
+            let cmd_opt = parse_command_from_broadcast(text)
+                .or_else(|| serde_json::from_str::<TunnelCommand>(text).ok());
+
+            if let Some(cmd) = cmd_opt {
+                // 回调内执行指令路由(Tauri command);回调失败不影响收发循环
+                let fut = on_command(cmd);
+                fut.await;
+            } else {
+                // 非 Command 消息(Control/Event 回环/未知):忽略,不中断
+                tracing::debug!(text = %text.chars().take(200).collect::<String>(), "收到非 Command 入站消息,忽略");
+            }
+            true
+        }
+        WsMessage::Binary(_) => {
+            tracing::debug!("收到二进制帧,忽略");
+            true
+        }
+        WsMessage::Ping(_) => {
+            // tungstenite 协议层自动应答 Pong,这里不处理
+            true
+        }
+        WsMessage::Pong(_) => true,
+        WsMessage::Close(_) => false,
+        WsMessage::Frame(_) => true, // 原始帧,上层已聚合,忽略
+    }
+}
+
+/// 从 BroadcastMessage JSON 提取 TunnelCommand
+///
+/// df-relay 入站包成 `BroadcastMessage { ..., payload: <原文本解析为 Value> }`,
+/// 故 payload 字段即 TunnelCommand 序列化后的 JSON 对象(tag="kind")。
+/// 此处只镜像解析 payload 字段(避免依赖 df-relay crate),payload 用 Value 透传不耦合。
+fn parse_command_from_broadcast(raw: &str) -> Option<TunnelCommand> {
+    // 仅取 payload 字段,避整结构强类型耦合(device_id/source 等字段本客户端不关心)
+    #[derive(serde::Deserialize)]
+    struct BroadcastLike {
+        #[serde(default)]
+        payload: Option<serde_json::Value>,
+        #[serde(default)]
+        kind: Option<String>,
+    }
+    let parsed: BroadcastLike = serde_json::from_str(raw).ok()?;
+    // 仅 kind == "command" 时才尝试提 TunnelCommand(Event/Control 不提)
+    if parsed.kind.as_deref() != Some("command") {
+        return None;
+    }
+    let payload = parsed.payload?;
+    serde_json::from_value::<TunnelCommand>(payload).ok()
+}
+
+/// 判断是否为 relay 控制面错误帧
+fn parse_relay_error(msg: &WsMessage) -> Option<RelayControlError> {
+    if let WsMessage::Text(t) = msg {
+        serde_json::from_str::<RelayControlError>(t).ok()
+    } else {
+        None
+    }
+}
+
+/// 计算指数退避延迟(供未来 supervisor 重连使用,本任务未直接调用,但属完整重连语义的一部分)
+#[allow(dead_code)]
+fn backoff_delay(attempt: u32) -> Duration {
+    // 1s, 2s, 4s, 8s, 16s, 30s, 30s, ...
+    let secs = RECONNECT_BASE
+        .as_secs()
+        .saturating_mul(1u64 << attempt.min(5));
+    Duration::from_secs(secs.min(RECONNECT_MAX.as_secs()))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn backoff_caps_at_max() {
+        assert_eq!(backoff_delay(0), RECONNECT_BASE);
+        assert_eq!(backoff_delay(1), Duration::from_secs(2));
+        assert_eq!(backoff_delay(5), Duration::from_secs(32).min(RECONNECT_MAX));
+        assert_eq!(backoff_delay(10), RECONNECT_MAX);
+    }
+
+    #[test]
+    fn parse_command_from_broadcast_extracts_payload() {
+        // 模拟 relay 转发的 BroadcastMessage
+        let raw = r#"{"device_id":"dev-1","kind":"command","source":{"0":42},"from":"miniapp","payload":{"kind":"send","conv_id":"c1","content":"hi"},"ts":1700000000000}"#;
+        let cmd = parse_command_from_broadcast(raw).expect("应提取出 TunnelCommand");
+        match cmd {
+            TunnelCommand::Send { conv_id, content } => {
+                assert_eq!(conv_id, "c1");
+                assert_eq!(content, "hi");
+            }
+            other => panic!("预期 Send,实际 {other:?}"),
+        }
+    }
+
+    #[test]
+    fn parse_command_ignores_event_kind() {
+        let raw = r#"{"device_id":"dev-1","kind":"event","source":{"0":1},"from":"device","payload":{"kind":"text_delta","conv_id":"c1","delta":"x"},"ts":1}"#;
+        assert!(parse_command_from_broadcast(raw).is_none());
+    }
+
+    #[test]
+    fn parse_relay_error_detects_auth_failure() {
+        let msg = WsMessage::Text(r#"{"kind":"control","error":"auth_failed"}"#.into());
+        let err = parse_relay_error(&msg).expect("应解析出错误帧");
+        assert_eq!(err.error, "auth_failed");
     }
 }