ieee80154: process packets without the FCS.

We assume the FCS is checked by lower layers or by hardware.

- Makes it consistent with Ethernet mediums, where we don't handle the FCS either.
- Linux ieee802154 raw sockets send/receive packets without the FCS.

src/iface/interface.rs

@@ -1136,7 +1136,6 @@ impl<'a> InterfaceInner<'a> {
         let payload = iphc_packet.payload();
         let ip_repr = IpRepr::Sixlowpan(iphc_repr);
 
-
         // Currently we assume the next header is a UDP, so we mark all the rest with todo.
         match iphc_repr.next_header {
             SixlowpanNextHeader::Compressed => {
@@ -2421,8 +2420,6 @@ impl<'a> InterfaceInner<'a> {
                     _ => return Err(Error::Unrecognized),
                 }
 
-                //tx_len += 2; // XXX: FCS calculation not needed when doing it in hardware
-
                 tx_token.consume(cx.now, tx_len, |mut tx_buffer| {
                     // 1. Create the header of 802.15.4
                     let mut ieee_packet = Ieee802154Frame::new_unchecked(&mut tx_buffer);
@@ -2465,10 +2462,6 @@ impl<'a> InterfaceInner<'a> {
                         _ => return Err(Error::Unrecognized),
                     }
 
-                    //let fcs = crate::wire::ieee802154::calculate_crc(&tx_buffer[..tx_len-2]);
-                    //tx_buffer[tx_len-1] = ((fcs >> 8) & 0xff) as u8;
-                    //tx_buffer[tx_len-2] = (fcs & 0xff) as u8;
-
                     Ok(())
                 })
             }

src/wire/ieee802154.rs

@@ -516,12 +516,6 @@ impl<T: AsRef<[u8]>> Frame<T> {
 
         todo!();
     }
-
-    /// Return the FCS fields
-    #[inline]
-    pub fn fcs(&self) -> &[u8] {
-        &self.buffer.as_ref()[self.buffer.as_ref().len() - 2..]
-    }
 }
 
 impl<'a, T: AsRef<[u8]> + ?Sized> Frame<&'a T> {
@@ -533,7 +527,7 @@ impl<'a, T: AsRef<[u8]> + ?Sized> Frame<&'a T> {
                 let data = &self.buffer.as_ref()[field::ADDRESSING];
                 let offset = self.addressing_fields().unwrap().len();
 
-                Some(&data[offset..data.len() - 2]) // Remove the FCS field of the IEEE80.15.4 frame.
+                Some(&data[offset..])
             }
             _ => None,
         }
@@ -692,14 +686,13 @@ impl<T: AsRef<[u8]>> fmt::Display for Frame<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(
             f,
-            "IEEE802.15.4 frame type={} seq={:2x?} dst_pan={:x?} dest={:x?} src_pan={:?} src={:x?} fcs={:x?}",
+            "IEEE802.15.4 frame type={} seq={:2x?} dst_pan={:x?} dest={:x?} src_pan={:?} src={:x?}",
             self.frame_type(),
             self.sequence_number(),
             self.dst_pan_id(),
             self.dst_addr(),
             self.src_pan_id(),
             self.src_addr(),
-            self.fcs(),
         )
     }
 }
@@ -908,7 +901,6 @@ mod test {
             0xff, 0xff, // Short destination address
             0xc7, 0xd9, 0xb5, 0x14, 0x00, 0x4b, 0x12, 0x00, // Extended source address
             0x2b, 0x00, 0x00, 0x00, // payload
-            0xb3, 0x0d // FSM
         ];
         frame_type -> FrameType::Data,
         security_enabled -> false,
@@ -919,6 +911,5 @@ mod test {
         frame_version -> FrameVersion::Ieee802154_2006,
         src_addressing_mode -> AddressingMode::Extended,
         //payload -> Some(&[0x2b, 0x00, 0x00, 0x00]),
-        fcs -> [0xb3, 0x0d],
     }
 }