Struct SegmentPreamble 

pub struct SegmentPreamble {
    pub magic: [u8; 4],
    pub version: u16,
    pub cipher_alg: u8,
    pub kid: u8,
    pub epoch: [u8; 4],
}

Preamble written at offset 0 of every segment file (WAL or storage).

Fields

magic: [u8; 4]

File-type magic: WAL_PREAMBLE_MAGIC or SEG_PREAMBLE_MAGIC.

version: u16

Layout version (must equal PREAMBLE_VERSION).

cipher_alg: u8

Cipher algorithm: 0 = AES-256-GCM.

kid: u8

Key ID within the active key ring (0 = current KEK).

epoch: [u8; 4]

Random epoch generated at WAL-lifetime start; used as the high 4 bytes of every AES-GCM nonce in this segment.

Implementations

impl SegmentPreamble

pub fn new_wal(epoch: [u8; 4]) -> Self

Construct a new preamble for a WAL segment.

pub fn new_seg(epoch: [u8; 4]) -> Self

Construct a new preamble for a storage segment.

pub fn to_bytes(&self) -> [u8; 16]

Serialize to exactly PREAMBLE_SIZE bytes.

pub fn from_bytes(buf: &[u8; 16], expected_magic: &[u8; 4]) -> Result<Self>

Deserialize and validate a preamble, checking magic and version.

expected_magic must be either WAL_PREAMBLE_MAGIC or SEG_PREAMBLE_MAGIC.

pub fn epoch(&self) -> &[u8; 4]

The epoch bytes, for passing to nonce construction.

Trait Implementations

impl Clone for SegmentPreamble

fn clone(&self) -> SegmentPreamble

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SegmentPreamble

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

Formats the value using the given formatter.

impl PartialEq for SegmentPreamble

fn eq(&self, other: &SegmentPreamble) -> 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 Copy for SegmentPreamble

impl Eq for SegmentPreamble

impl StructuralPartialEq for SegmentPreamble