use workspace, prepare for config server and gui (#48)

easytier/src/common/netns.rs

@@ -0,0 +1,114 @@
+use futures::Future;
+
+#[cfg(target_os = "linux")]
+use nix::sched::{setns, CloneFlags};
+#[cfg(target_os = "linux")]
+use std::os::fd::AsFd;
+
+pub struct NetNSGuard {
+    #[cfg(target_os = "linux")]
+    old_ns: Option<std::fs::File>,
+}
+
+pub static ROOT_NETNS_NAME: &str = "_root_ns";
+
+#[cfg(target_os = "linux")]
+impl NetNSGuard {
+    pub fn new(ns: Option<String>) -> Box<Self> {
+        let old_ns = if ns.is_some() {
+            let old_ns = if cfg!(target_os = "linux") {
+                Some(std::fs::File::open("/proc/self/ns/net").unwrap())
+            } else {
+                None
+            };
+            Self::switch_ns(ns);
+            old_ns
+        } else {
+            None
+        };
+        Box::new(NetNSGuard { old_ns })
+    }
+
+    fn switch_ns(name: Option<String>) {
+        if name.is_none() {
+            return;
+        }
+
+        let ns_path: String;
+        let name = name.unwrap();
+        if name == ROOT_NETNS_NAME {
+            ns_path = "/proc/1/ns/net".to_string();
+        } else {
+            ns_path = format!("/var/run/netns/{}", name);
+        }
+
+        let ns = std::fs::File::open(ns_path).unwrap();
+        log::info!(
+            "[INIT NS] switching to new ns_name: {:?}, ns_file: {:?}",
+            name,
+            ns
+        );
+
+        setns(ns.as_fd(), CloneFlags::CLONE_NEWNET).unwrap();
+    }
+}
+
+#[cfg(target_os = "linux")]
+impl Drop for NetNSGuard {
+    fn drop(&mut self) {
+        if self.old_ns.is_none() {
+            return;
+        }
+        log::info!("[INIT NS] switching back to old ns, ns: {:?}", self.old_ns);
+        setns(
+            self.old_ns.as_ref().unwrap().as_fd(),
+            CloneFlags::CLONE_NEWNET,
+        )
+        .unwrap();
+    }
+}
+
+#[cfg(not(target_os = "linux"))]
+impl NetNSGuard {
+    pub fn new(_ns: Option<String>) -> Box<Self> {
+        Box::new(NetNSGuard {})
+    }
+}
+
+#[derive(Clone)]
+pub struct NetNS {
+    name: Option<String>,
+}
+
+impl NetNS {
+    pub fn new(name: Option<String>) -> Self {
+        NetNS { name }
+    }
+
+    pub async fn run_async<F, Fut, Ret>(&self, f: F) -> Ret
+    where
+        F: FnOnce() -> Fut,
+        Fut: Future<Output = Ret>,
+    {
+        // TODO: do we really need this lock
+        // let _lock = LOCK.lock().await;
+        let _guard = NetNSGuard::new(self.name.clone());
+        f().await
+    }
+
+    pub fn run<F, Ret>(&self, f: F) -> Ret
+    where
+        F: FnOnce() -> Ret,
+    {
+        let _guard = NetNSGuard::new(self.name.clone());
+        f()
+    }
+
+    pub fn guard(&self) -> Box<NetNSGuard> {
+        NetNSGuard::new(self.name.clone())
+    }
+
+    pub fn name(&self) -> Option<String> {
+        self.name.clone()
+    }
+}