FaultMask Bitfield (0x00..0x80)
u64se-seu-solana records all failure modalities as a transparent 8-bit bitmask (FaultMask).
#![allow(unused)]
fn main() {
#[repr(transparent)]
#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
pub struct FaultMask(pub u8);
}Canonical Bit Allocation
| Bit | Hex | Constant Identifier | Formal Invariant Violated |
|---|---|---|---|
— | 0x00 | FaultMask::PASS | All invariants satisfied (0 violations) |
0 | 0x01 | INACTIVE_OR_PAUSED | State machine is halted, paused, or uninitialized |
1 | 0x02 | ROLE_UNAUTHORIZED | Caller requested a forbidden role or multi-hot bitmask |
2 | 0x04 | TARGET_MISMATCH | Expected target coordinate does not match committed target |
3 | 0x08 | SELF_LOOP_FORBIDDEN | Illegal self-loop transition ($S_{i+1} = S_i$) |
4 | 0x10 | BACKWARD_FORBIDDEN | Illegal backward/re-entrant transition ($S_{i+1} < S_i$) |
5 | 0x20 | SLOT_TIME_SKEW | Clock drift from past epoch ($\Delta > \text{0x7FFF}$) |
6 | 0x40 | RATE_LIMITED | Slot collision; duplicate transition within same slot ($\Delta = 0$) |
7 | 0x80 | VALUE_OVERFLOW | Reserved for arithmetic coordinate boundary breach |
Multiple Concurrent Fault Recording
Because FaultMask is a bitfield, a single evaluation step captures all simultaneous violations rather than short-circuiting on the first error.
For example, if an attacker attempts a backward transition with an unauthorized multi-bit role: $$\text{fault} = \text{ROLE_UNAUTHORIZED (0x02)} \mid \text{BACKWARD_FORBIDDEN (0x10)} = \mathbf{0x12}$$
This gives client-side monitors, MEV searchers, and circuit breakers complete observability into why an action was fenced off.
Helper Methods
#![allow(unused)]
fn main() {
impl FaultMask {
/// Returns true if and only if zero fault bits are active.
#[inline(always)]
pub const fn is_pass(&self) -> bool {
self.0 == Self::PASS
}
/// Tests for specific fault conditions.
#[inline(always)]
pub const fn contains(&self, bit: u8) -> bool {
(self.0 & bit) != 0
}
}
}