1 files changed, 20 insertions, 33 deletions

diff --git a/embassy-net/src/stack.rs b/embassy-net/src/stack.rs
index 3a7610758..5c4fb0442 100644
--- a/embassy-net/src/stack.rs
+++ b/embassy-net/src/stack.rs
@@ -1,4 +1,4 @@
-use core::cell::UnsafeCell;
+use core::cell::RefCell;
 use core::future::{poll_fn, Future};
 use core::task::{Context, Poll};
 
@@ -62,8 +62,8 @@ pub enum ConfigStrategy {
 }
 
 pub struct Stack<D: Device> {
-    pub(crate) socket: UnsafeCell<SocketStack>,
-    inner: UnsafeCell<Inner<D>>,
+    pub(crate) socket: RefCell<SocketStack>,
+    inner: RefCell<Inner<D>>,
 }
 
 struct Inner<D: Device> {
@@ -81,8 +81,6 @@ pub(crate) struct SocketStack {
     next_local_port: u16,
 }
 
-unsafe impl<D: Device> Send for Stack<D> {}
-
 impl<D: Device + 'static> Stack<D> {
     pub fn new<const ADDR: usize, const SOCK: usize, const NEIGH: usize>(
         device: D,
@@ -143,40 +141,38 @@ impl<D: Device + 'static> Stack<D> {
         }
 
         Self {
-            socket: UnsafeCell::new(socket),
-            inner: UnsafeCell::new(inner),
+            socket: RefCell::new(socket),
+            inner: RefCell::new(inner),
         }
     }
 
-    /// SAFETY: must not call reentrantly.
-    unsafe fn with<R>(&self, f: impl FnOnce(&SocketStack, &Inner<D>) -> R) -> R {
-        f(&*self.socket.get(), &*self.inner.get())
+    fn with<R>(&self, f: impl FnOnce(&SocketStack, &Inner<D>) -> R) -> R {
+        f(&*self.socket.borrow(), &*self.inner.borrow())
     }
 
-    /// SAFETY: must not call reentrantly.
-    unsafe fn with_mut<R>(&self, f: impl FnOnce(&mut SocketStack, &mut Inner<D>) -> R) -> R {
-        f(&mut *self.socket.get(), &mut *self.inner.get())
+    fn with_mut<R>(&self, f: impl FnOnce(&mut SocketStack, &mut Inner<D>) -> R) -> R {
+        f(&mut *self.socket.borrow_mut(), &mut *self.inner.borrow_mut())
     }
 
     pub fn ethernet_address(&self) -> [u8; 6] {
-        unsafe { self.with(|_s, i| i.device.device.ethernet_address()) }
+        self.with(|_s, i| i.device.device.ethernet_address())
     }
 
     pub fn is_link_up(&self) -> bool {
-        unsafe { self.with(|_s, i| i.link_up) }
+        self.with(|_s, i| i.link_up)
     }
 
     pub fn is_config_up(&self) -> bool {
-        unsafe { self.with(|_s, i| i.config.is_some()) }
+        self.with(|_s, i| i.config.is_some())
     }
 
     pub fn config(&self) -> Option<Config> {
-        unsafe { self.with(|_s, i| i.config.clone()) }
+        self.with(|_s, i| i.config.clone())
     }
 
     pub async fn run(&self) -> ! {
         poll_fn(|cx| {
-            unsafe { self.with_mut(|s, i| i.poll(cx, s)) }
+            self.with_mut(|s, i| i.poll(cx, s));
             Poll::<()>::Pending
         })
         .await;
@@ -270,21 +266,12 @@ impl<D: Device + 'static> Inner<D> {
                     None => {}
                     Some(dhcpv4::Event::Deconfigured) => self.unapply_config(s),
                     Some(dhcpv4::Event::Configured(config)) => {
-                        let mut dns_servers = Vec::new();
-                        for s in &config.dns_servers {
-                            if let Some(addr) = s {
-                                dns_servers.push(addr.clone()).unwrap();
-                            }
-                        }
-
-                        self.apply_config(
-                            s,
-                            Config {
-                                address: config.address,
-                                gateway: config.router,
-                                dns_servers,
-                            },
-                        )
+                        let config = Config {
+                            address: config.address,
+                            gateway: config.router,
+                            dns_servers: config.dns_servers,
+                        };
+                        self.apply_config(s, config)
                     }
                 }
             } else if old_link_up {