Function resolve

src/resolver.rs:213–270

(
    globals: &Globals,
    packet: &mut Vec<u8>,
    packet_qname: Vec<u8>,
    cached_response: Option<CachedResponse>,
    packet_hash: u128,
    original_tid: u16,
)

}

pub async fn resolve(
    globals: &Globals,
    packet: &mut Vec<u8>,
    packet_qname: Vec<u8>,
    cached_response: Option<CachedResponse>,
    packet_hash: u128,
    original_tid: u16,
) -> Result<Vec<u8>, Error> {
    #[cfg(feature = "metrics")]
    globals.varz.upstream_sent.inc();
    let tid = random();
    dns::set_tid(packet, tid);
    let mut response = resolve_udp(
        globals,
        packet,
        &packet_qname,
        tid,
        cached_response.is_some(),
    )
    .await?;
    if dns::is_truncated(&response) {
        response = resolve_tcp(globals, packet, &packet_qname, tid).await?;
    }
    #[cfg(feature = "metrics")]
    {
        globals.varz.upstream_received.inc();
        if dns::rcode_nxdomain(&response) {
            globals.varz.upstream_rcode_nxdomain.inc();
        }
    }
    if dns::rcode_servfail(&response) || dns::rcode_refused(&response) {
        trace!("SERVFAIL/REFUSED: {}", dns::rcode(&response));
        if let Some(cached_response) = cached_response {
            trace!("Serving stale");
            #[cfg(feature = "metrics")]
            {
                globals.varz.client_queries_offline.inc();
                globals.varz.client_queries_cached.inc();
            }
            return Ok(cached_response.into_response());
        } else {
            #[cfg(feature = "metrics")]
            globals.varz.upstream_errors.inc();
        }
    } else {
        trace!("Adding to cache");
        let cached_response = CachedResponse::new(&globals.cache, response.clone());
        globals.cache.lock().insert(packet_hash, cached_response);
    }
    dns::set_tid(&mut response, original_tid);
    dns::recase_qname(&mut response, &packet_qname)?;
    #[cfg(feature = "metrics")]
    globals
        .varz
        .upstream_response_sizes
        .observe(response.len() as f64);
    Ok(response)
}