Struct ScionTxtDnsResolver 

pub struct ScionTxtDnsResolver { /* private fields */ }

Resolver that interprets TXT records using the TSAR format.

Use this resolver to look up scion=v1;... TXT records and translate them into ScionIpAddr values. Construction errors are reported via TxtResolverError, while lookup failures and parsing outcomes are reported through ResolveError from ScionDnsResolver::resolve.

Domain-specific overrides can be added to bypass DNS and always return the configured addresses.

Caching

This type holds no cache of its own. Lookups are cached by the DNS core underneath, at the records’ own TTLs, and that cache covers negative answers too: a name without TXT records is remembered for the negative TTL of the zone’s SOA. Clones share that cache; dropping the last clone drops the cache with it.

Callers who need different bounds, or no caching at all, set ResolverOpts (cache_size, positive_min_ttl, positive_max_ttl, negative_min_ttl, negative_max_ttl) on the builder returned by ScionTxtDnsResolver::builder before passing it to ScionTxtDnsResolver::from_builder. Bounding staleness means bounding it there; a cache added above this type could not do so, because on expiry it would only re-read the copy the DNS core still holds.

Implementations

impl ScionTxtDnsResolver

pub fn new() -> Result<Self, TxtResolverError>

Create a resolver using the system DNS configuration.

This uses the OS resolver configuration (for example /etc/resolv.conf) and then applies the default hickory-dns options for lookups.

Errors

Returns TxtResolverError if the system configuration cannot be loaded.

pub fn with_override(self, domain: &str, addrs: Vec<ScionIpAddr>) -> Self

Override DNS resolution for a specific domain.

pub fn with_overrides<D, I>(self, overrides: I) -> Self

where D: Into<String>, I: IntoIterator<Item = (D, Vec<ScionIpAddr>)>,

Override DNS resolution for multiple domains at once.

pub fn from_builder( builder: ResolverBuilder<TokioConnectionProvider>, ) -> Result<Self, TxtResolverError>

Constructs a resolver from a pre-configured hickory ResolverBuilder.

This allows callers to customize resolver options (timeouts, retries, name servers) via hickory-dns before constructing the resolver.

Errors

This function is currently infallible, but returns Result for future compatibility with hickory-dns builder changes.

pub fn builder() -> Result<ResolverBuilder<TokioConnectionProvider>, TxtResolverError>

Creates a builder for configuring resolver options.

On Linux/macOS the builder is initialized from the system DNS configuration (/etc/resolv.conf). On Android and iOS, which do not expose /etc/resolv.conf, Google Public DNS is used as a fallback.

The returned builder can be adjusted before calling ScionTxtDnsResolver::from_builder.

Errors

Returns TxtResolverError if system configuration cannot be loaded (non-Android/iOS platforms only).

Trait Implementations

impl Clone for ScionTxtDnsResolver

fn clone(&self) -> ScionTxtDnsResolver

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ScionTxtDnsResolver

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

Formats the value using the given formatter.

impl ScionDnsResolver for ScionTxtDnsResolver

fn resolve<'life0, 'life1, 'async_trait>( &'life0 self, domain: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<Vec<ScionIpAddr>, ResolveError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Resolve a domain into SCION addresses.