Enum DecodeError 

pub enum DecodeError {
    BadMagic,
    BadVersion,
    BadCrc {
        expected: u32,
        actual: u32,
    },
    BadStatus(u8),
    StallOnWire,
    BadPid(u32),
    BadTimestamp(u64),
    BadNonce {
        nonce: u64,
        status: Status,
    },
}

Error returned by Frame::decode and Status::try_from_u8.

The variants form an exhaustive list of validation failures the protocol can detect statically; everything else (timestamp drift, nonce regression) is policy enforced higher in the stack.

This enum is exhaustive. Adding a variant is a workspace-wide compile-error change that requires updating every match site explicitly.

Variants

BadMagic

First two bytes did not equal MAGIC.

BadVersion

Version byte did not equal VERSION.

BadCrc

CRC-32C trailer at bytes 28..32 did not match the value computed over bytes 0..28. Indicates wire corruption (cosmic ray / NIC firmware / non-ECC RAM bit flip) on the UDS transport, or in-process memory corruption between crate::crypto::open and Frame::decode on the secure-UDP transport. AEAD tag failures stay in the transport layer (crypto::AuthError) and never surface as BadCrc.

Fields

expected: u32

CRC-32C recomputed over bytes 0..28 of the received frame.

actual: u32

CRC-32C value carried in bytes 28..32 of the received frame.

BadStatus(u8)

Status byte did not match any known Status variant. The inner value is the offending byte, surfaced for observer-side diagnostics.

StallOnWire

Observer-only status Status::Stall observed on the wire. Stall is synthesized by varta-watch when a pid goes silent past its threshold; agents emit only Ok, Degraded, or Critical. A spoofed Stall frame would inject false liveness telemetry from any pid, so the decoder rejects it at the single chokepoint.

BadPid(u32)

Reserved pid: 0 (kernel/scheduler) or 1 (init/systemd). No legitimate agent runs at either pid; rejecting closes the “spoof init has stalled” recovery-trigger attack on UDP listeners.

BadTimestamp(u64)

Reserved timestamp sentinel u64::MAX — the saturation value from varta_client::Varta::beat’s .min(u64::MAX as u128) as u64. Reaching it through real elapsed nanoseconds is not physically possible.

BadNonce

Protocol invariant violation: nonce == NONCE_TERMINAL is reserved for the panic hook’s terminal frame and MUST be paired with Status::Critical. Carries the violating status for diagnostics.

Fields

nonce: u64

The terminal-sentinel nonce value observed on the wire.

status: Status

The status byte that was paired with the sentinel nonce.

Trait Implementations

impl Clone for DecodeError

fn clone(&self) -> DecodeError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for DecodeError

impl Debug for DecodeError

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

Formats the value using the given formatter.

impl Display for DecodeError

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

Formats the value using the given formatter.

impl Eq for DecodeError

impl Error for DecodeError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for DecodeError

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for DecodeError