//! aura-pki — mutual X.509 authentication for the Aura VPN.
//!
//! A self-signed Aura CA ([`AuraCa`]) issues a server certificate (carrying a
//! DNS SAN) and per-client certificates (`CN = client_id`). The server verifies
//! client certificates against the CA and the client verifies the server
//! certificate against the CA via [`AuraCertVerifier`]. v1 revocation is a
//! simple CRL: a set of revoked certificate serials or client ids, see
//! [`AuraCertVerifier::set_revoked`] and [`CrlStore`].
//!
//! Certificates use ECDSA P-256 / SHA-256 keys (rcgen's default), and chain
//! verification is performed with `rustls-webpki` against the CA trust anchor.

mod ca;
mod cert;
mod store;

pub use ca::{AuraCa, IssuedCert};
pub use cert::AuraCertVerifier;
pub use store::CrlStore;

/// Errors produced by the Aura PKI.
#[derive(Debug, thiserror::Error)]
pub enum PkiError {
    /// A PEM/DER blob could not be parsed into a certificate.
    #[error("failed to parse certificate: {0}")]
    CertParse(String),

    /// The supplied certificate chain was empty.
    #[error("empty certificate chain")]
    EmptyChain,

    /// The trust anchor (CA certificate) could not be constructed.
    #[error("invalid trust anchor: {0}")]
    TrustAnchor(String),

    /// Chain verification against the CA failed (bad signature, expired,
    /// untrusted issuer, wrong key usage, ...).
    #[error("certificate chain verification failed: {0}")]
    Verification(String),

    /// The server certificate is not valid for the requested name.
    #[error("certificate is not valid for name '{0}'")]
    NameMismatch(String),

    /// The end-entity certificate did not contain the expected identity, e.g. a
    /// client certificate without a Common Name.
    #[error("missing identity in certificate: {0}")]
    MissingIdentity(String),

    /// The certificate was found in the revocation list.
    #[error("certificate is revoked: {0}")]
    Revoked(String),
}