[mio] 完善错误处理

vnt/tun/src/packet/ethernet/packet.rs

@@ -21,7 +21,7 @@ impl<B: AsRef<[u8]>> EthernetPacket<B> {
         let packet = EthernetPacket::unchecked(buffer);
         //头部固定14位
         if packet.buffer.as_ref().len() < 14 {
-            Err(io::Error::from(io::ErrorKind::InvalidData))?;
+            Err(io::Error::new(io::ErrorKind::InvalidData,format!("len={}", packet.buffer.as_ref().len())))?;
         }
 
         Ok(packet)

vnt/tun/src/packet/mod.rs

@@ -13,8 +13,11 @@ where
     let mut eth_buf = [0; 65536];
     loop {
         let len = read_fn(&mut eth_buf)?;
+        if len == 0{
+            return Ok(len);
+        }
         //处理arp包
-        let mut ether = ethernet::packet::EthernetPacket::unchecked(&mut eth_buf[..len]);
+        let mut ether = ethernet::packet::EthernetPacket::new(&mut eth_buf[..len])?;
         match ether.protocol() {
             Protocol::Ipv4 => {
                 let len = ether.payload().len();