Implement requesting tun_fd with tokio channel. (#1734)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

easytier/src/launcher.rs

@@ -16,16 +16,20 @@ use crate::{
 };
 use anyhow::Context;
 use chrono::{DateTime, Local};
-use std::net::SocketAddr;
 use std::{
     collections::VecDeque,
-    sync::{atomic::AtomicBool, Arc, RwLock},
+    net::SocketAddr,
+    sync::{atomic::AtomicBool, Arc, Mutex, RwLock},
+};
+use tokio::{
+    sync::{broadcast, mpsc},
+    task::JoinSet,
 };
-use tokio::{sync::broadcast, task::JoinSet};
 
 pub type MyNodeInfo = crate::proto::api::manage::MyNodeInfo;
 
 type ArcMutApiService = Arc<RwLock<Option<Arc<dyn InstanceRpcService>>>>;
+type TunFd = Option<i32>;
 
 #[derive(serde::Serialize, Clone)]
 pub struct Event {
@@ -35,7 +39,7 @@ pub struct Event {
 
 struct EasyTierData {
     events: RwLock<VecDeque<Event>>,
-    tun_fd: Arc<RwLock<Option<i32>>>,
+    tun_fd: (mpsc::Sender<TunFd>, Mutex<Option<mpsc::Receiver<TunFd>>>),
     event_subscriber: RwLock<broadcast::Sender<GlobalCtxEvent>>,
     instance_stop_notifier: Arc<tokio::sync::Notify>,
 }
@@ -43,10 +47,11 @@ struct EasyTierData {
 impl Default for EasyTierData {
     fn default() -> Self {
         let (tx, _) = broadcast::channel(16);
+        let (sender, receiver) = mpsc::channel(16);
         Self {
             event_subscriber: RwLock::new(tx),
             events: RwLock::new(VecDeque::new()),
-            tun_fd: Arc::new(RwLock::new(None)),
+            tun_fd: (sender, Mutex::new(Some(receiver))),
             instance_stop_notifier: Arc::new(tokio::sync::Notify::new()),
         }
     }
@@ -98,24 +103,25 @@ impl EasyTierLauncher {
         let peer_mgr = instance.get_peer_manager();
         let nic_ctx = instance.get_nic_ctx();
         let peer_packet_receiver = instance.get_peer_packet_receiver();
-        let arc_tun_fd = data.tun_fd.clone();
+        let mut tun_fd_receiver = data.tun_fd.1.lock().unwrap().take().unwrap();
 
         tasks.spawn(async move {
-            let mut old_tun_fd = arc_tun_fd.read().unwrap().clone();
+            let mut old_tun_fd = None;
             loop {
-                tokio::time::sleep(std::time::Duration::from_secs(1)).await;
-                let tun_fd = arc_tun_fd.read().unwrap().clone();
-                if tun_fd != old_tun_fd && tun_fd.is_some() {
+                let Some(tun_fd) = tun_fd_receiver.recv().await.flatten() else {
+                    return;
+                };
+                if Some(tun_fd) != old_tun_fd {
                     let res = Instance::setup_nic_ctx_for_android(
                         nic_ctx.clone(),
                         global_ctx.clone(),
                         peer_mgr.clone(),
                         peer_packet_receiver.clone(),
-                        tun_fd.unwrap(),
+                        tun_fd,
                     )
                     .await;
                     if res.is_ok() {
-                        old_tun_fd = tun_fd;
+                        old_tun_fd = Some(tun_fd);
                     }
                 }
             }
@@ -395,10 +401,16 @@ impl NetworkInstance {
 
     pub fn set_tun_fd(&mut self, tun_fd: i32) {
         if let Some(launcher) = self.launcher.as_ref() {
-            launcher.data.tun_fd.write().unwrap().replace(tun_fd);
+            let _ = launcher.data.tun_fd.0.blocking_send(Some(tun_fd));
         }
     }
 
+    pub fn get_tun_fd_sender(&self) -> Option<mpsc::Sender<TunFd>> {
+        self.launcher
+            .as_ref()
+            .map(|launcher| launcher.data.tun_fd.0.clone())
+    }
+
     pub fn start(&mut self) -> Result<EventBusSubscriber, anyhow::Error> {
         if self.is_easytier_running() {
             return Ok(self.subscribe_event().unwrap());