Module framer

Implements IEEE 802.15.4 MAC device abstraction over a 802.15.4 MAC interface.

Allows its users to prepare and send frames in plaintext, handling 802.15.4 encoding and security procedures (in the future) transparently.

However, certain IEEE 802.15.4 MAC device concepts are not implemented in this layer of abstraction and instead handled in hardware for performance purposes. These include CSMA-CA backoff, FCS generation and authentication, and automatic acknowledgement. Radio power management and channel selection is also passed down to the MAC control layer.

Usage

To use this capsule, we need an implementation of a hardware capsules_extra::ieee802154::mac::Mac. Suppose we have such an implementation of type XMacDevice.

let xmac: &XMacDevice = /* ... */;
let mac_device = static_init!(
    capsules_extra::ieee802154::mac::Framer<'static, XMacDevice>,
    capsules_extra::ieee802154::mac::Framer::new(xmac));
xmac.set_transmit_client(mac_device);
xmac.set_receive_client(mac_device, &mut MAC_RX_BUF);
xmac.set_config_client(mac_device);

The mac_device device is now set up. Users of the MAC device can now configure the underlying radio, prepare and send frames:

mac_device.set_pan(0xABCD);
mac_device.set_address(0x1008);
mac_device.config_commit();

let frame = mac_device
    .prepare_data_frame(&mut STATIC_BUFFER,
                        0xABCD, MacAddress::Short(0x1008),
                        0xABCD, MacAddress::Short(0x1009),
                        None)
    .ok()
    .map(|frame| {
        let rval = frame.append_payload(&mut SOME_DATA[..10]);
        if rval == Ok(()) {
            let (rval, _) = mac_device.transmit(frame);
            rval
        } else {
            rval
        }
    });

You should also be able to set up the userspace driver for receiving/sending 802.15.4 frames:

use kernel::static_init;

let radio_capsule = static_init!(
    capsules_extra::ieee802154::RadioDriver<'static>,
    capsules_extra::ieee802154::RadioDriver::new(mac_device, board_kernel.create_grant(&grant_cap), &mut RADIO_BUF));
mac_device.set_key_procedure(radio_capsule);
mac_device.set_device_procedure(radio_capsule);
mac_device.set_transmit_client(radio_capsule);
mac_device.set_receive_client(radio_capsule);

Structs

• Frame
  Wraps a static mutable byte slice along with header information for a payload.
• Framer
  Wraps an IEEE 802.15.4 kernel::hil::radio::Radio and exposes capsules_extra::ieee802154::mac::Mac functionality.

Constants

• CRYPT_BUF_SIZE
  The needed buffer size might be bigger than an MTU, because the CCM* authentication procedure

Traits

• DeviceProcedure
  IEEE 802.15.4-2015, 9.2.5, DeviceDescriptor lookup procedure.
• KeyProcedure
  IEEE 802.15.4-2015, 9.2.2, KeyDescriptor lookup procedure.

Functions

• get_ccm_nonce
  Generate a 15.4 CCM nonce from the device address, frame counter, and SecurityLevel