Move smoltcp-related code to bigtcp

kernel/libs/aster-bigtcp/src/device.rs

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: MPL-2.0
+
+pub use smoltcp::phy::{Device, Loopback, Medium};
+
+/// A trait that allows to obtain a mutable reference of [`Device`].
+///
+/// A [`Device`] is usually protected by a lock (e.g., a spin lock or a mutex), and it may be
+/// stored behind a shared type (e.g., an `Arc`). This property abstracts this fact by providing a
+/// method that the caller can use to get the mutable reference without worrying about how the
+/// reference is obtained.
+pub trait WithDevice: Send + Sync {
+    type Device: Device + ?Sized;
+
+    /// Calls the closure with a mutable reference of [`Device`].
+    fn with<F, R>(&self, f: F) -> R
+    where
+        F: FnOnce(&mut Self::Device) -> R;
+}