Struct Data 

pub struct Data {
    pub direction: Direction,
    pub confirmed: bool,
    pub dev_addr: DevAddr,
    pub f_ctrl: FCtrl,
    pub f_cnt: [u8; 2],
    pub f_opts: Vec<u8>,
    pub f_port: Option<u8>,
    pub frm_payload: Option<Vec<u8>>,
}

Fields of a Data message (confirmed or unconfirmed, uplink or downlink).

FRMPayload is encrypted on the wire; call Data::decrypt_payload to recover the plaintext. MAC commands in FOpts are encrypted only in LoRaWAN 1.1; call Data::decrypt_fopts when applicable.

Frame counters

The wire carries only the lower 16 bits of the 32-bit FCnt. The caller tracks the upper 16 bits and passes it to Data::f_cnt_32 and to every crypt / MIC call. Pass 0 for sessions that never wrap.

Fields

direction: Direction

Frame direction, inferred from MType.

confirmed: bool

true for ConfirmedData{Up,Down}.

dev_addr: DevAddr

Device address.

f_ctrl: FCtrl

Frame-control byte.

f_cnt: [u8; 2]

Lower 16 bits of FCnt as on the wire (little-endian).

Use Data::f_cnt for a u16 value or Data::f_cnt_32 for the full 32-bit counter with a caller-supplied upper half.

f_opts: Vec<u8>

MAC commands carried in FOpts (empty when none); up to 15 bytes. Encrypted with NwkSEncKey in 1.1; plaintext in 1.0.

f_port: Option<u8>

FPort byte. Some(0) means FRMPayload carries MAC commands; Some(p) with p > 0 means application data; None when neither FPort nor FRMPayload is present.

frm_payload: Option<Vec<u8>>

FRMPayload. Encrypted on the wire; replace with plaintext after Data::decrypt_payload.

Implementations

impl Data

pub const fn f_cnt(&self) -> u16

Lower 16 bits of FCnt as read from the wire (little-endian).

The wire stores only the bottom 16 bits of the actual 32-bit counter. For the full counter use Data::f_cnt_32 together with a caller-tracked upper half.

pub const fn f_cnt_32(&self, msb: u16) -> u32

Full 32-bit FCnt, combining the wire LSB16 with a caller-tracked MSB16.

msb is the upper 16 bits the caller has been tracking. Pass 0 if frame counters never wrap in your deployment; otherwise increment msb each time the wire counter rolls over from 0xFFFF to 0x0000.

impl Data

pub fn decrypt_payload( &self, app_s_key: &AppSKey, nwk_s_key: &NwkSKey, f_cnt_msb: u16, ) -> Result<Vec<u8>>

Decrypt FRMPayload.

LoRaWAN uses an AES-CTR-like keystream so the same operation works in both directions; this method is named for the typical use (receiver side). The key is selected by FPort:

• FPort == 0: NwkSKey (MAC commands in FRMPayload).
• FPort > 0: AppSKey (application data).

f_cnt_msb is the upper 16 bits of the 32-bit FCnt; pass 0 if frame counters never wrap. See crate::Data::f_cnt_32.

Errors

crate::Error::PayloadTooLarge if the ciphertext exceeds the AES-CTR block-index limit (255 blocks = 4080 bytes).

Examples

use lora_packet::{LoraPacket, AppSKey, NwkSKey};

let bytes = hex::decode("40f17dbe4900020001954378762b11ff0d")?;
let packet = LoraPacket::from_wire(&bytes)?;
let app_s_key = AppSKey::from_slice(&hex::decode("ec925802ae430ca77fd3dd73cb2cc588")?)?;
let nwk_s_key = NwkSKey::from_slice(&hex::decode("44024241ed4ce9a68c6a8bc055233fd3")?)?;
let plain = packet.as_data().unwrap().decrypt_payload(&app_s_key, &nwk_s_key, 0)?;
assert_eq!(&plain, b"test");

pub fn encrypt_payload( &self, plaintext: &[u8], app_s_key: &AppSKey, nwk_s_key: &NwkSKey, f_cnt_msb: u16, ) -> Result<Vec<u8>>

Encrypt the given plaintext under the FRMPayload keystream.

Same primitive as Self::decrypt_payload; named differently for clarity at call sites. Used by crate::LoraPacketBuilder::sign_and_encrypt for downlink building.

Selects NwkSKey when FPort == 0, AppSKey otherwise.

Errors

crate::Error::PayloadTooLarge if the plaintext exceeds 4080 bytes (255 AES blocks). Beyond this, the 1-byte block counter in the Ai keystream block overflows and silently produces ciphertext no other LoRaWAN stack can decrypt.

impl Data

pub fn decrypt_fopts( &self, nwk_s_enc_key: &NwkSEncKey, f_cnt_msb: u16, ) -> Result<Vec<u8>>

Decrypt FOpts MAC commands (LoRaWAN 1.1 only).

In 1.0, FOpts is plaintext on the wire; this method is a no-op (but still callable). In 1.1, FOpts is encrypted under NwkSEncKey with a single AES-ECB block.

Uses the keystream layout from the LoRa Alliance errata “FCntDwn Usage in FOpts Encryption” (CR v2 r1): when the frame is a downlink with FPort > 0 the aFCntDown flag selects byte 4 = 0x02; otherwise it is 0x01.

Errors

Currently infallible; returns Result for forward compatibility.

pub fn encrypt_fopts( &self, nwk_s_enc_key: &NwkSEncKey, f_cnt_msb: u16, ) -> Result<Vec<u8>>

Encrypt FOpts MAC commands (LoRaWAN 1.1 only).

Symmetric to Self::decrypt_fopts; same primitive in both directions. Use when building a 1.1 frame that carries MAC commands in FOpts.

Errors

Currently infallible; returns Result for forward compatibility.

Trait Implementations

impl Clone for Data

fn clone(&self) -> Data

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Data

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Data

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Data

fn eq(&self, other: &Data) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Data

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for Data

impl StructuralPartialEq for Data