net: fix incorrect poll_iface() calls

- poll_iface might be called by interrupt while poll_iface was being called in main loop
- Disable interrupt when poll_iface is being processed
- Only use IfacePollTimer to poll_iface

src/net/net.rs

@@ -220,7 +220,9 @@ impl ServerHandle {
     }
 
     pub fn poll_iface(&mut self) {
+        cortex_m::interrupt::free(|_| {
             self.iface.poll(now_fn(), &mut &mut self.dma, &mut self.socket_set);
+        });
     }
 
     pub fn poll_at_iface(&mut self) -> Option<Instant> {
@@ -246,8 +248,7 @@ impl ServerHandle {
         if num_bytes > 0 {
             match socket.send_slice(&buffer[..num_bytes]) {
                 Ok(_) => {
-                    self.poll_iface();
-                    info!("Sent {} bytes.", num_bytes);
+                    info!("Enqueued {} bytes.", num_bytes);
                 }
                 Err(err) => {
                     info!("Bytes cannot be sent. Error: {:?}", err)
@@ -515,11 +516,9 @@ pub fn for_each<F: FnMut(SocketHandle, usize)>(mut callback: F) {
 #[interrupt]
 fn ETH() {
     let interrupt_reason = stm32_eth::eth_interrupt_handler();
-    cortex_m::interrupt::free(|_| {
     if interrupt_reason.rx {
         eth_poll_iface();
     }
-    });
     debug!("Ethernet Interrupt{:?}", interrupt_reason);
 }