trust-dns-server 0.22.0

Trust-DNS is a safe and secure DNS server with DNSSec support. Eventually this could be a replacement for BIND9. The DNSSec support allows for live signing of all records, in it does not currently support records signed offline. The server supports dynamic DNS with SIG0 authenticated requests. Trust-DNS is based on the Tokio and Futures libraries, which means it should be easily integrated into other software that also use those libraries.
Documentation
// Copyright 2015-2021 Benjamin Fry <benjaminfry@me.com>
//
// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
// http://opensource.org/licenses/MIT>, at your option. This file may not be
// copied, modified, or distributed except according to those terms.

//! All authority related types

use std::{
    ops::{Deref, DerefMut},
    path::{Path, PathBuf},
    sync::Arc,
};

use futures_util::lock::Mutex;
use tracing::{error, info, warn};

use crate::{
    authority::{Authority, LookupError, LookupOptions, MessageRequest, UpdateResult, ZoneType},
    client::rr::{LowerName, RrKey},
    error::{PersistenceErrorKind, PersistenceResult},
    proto::{
        op::ResponseCode,
        rr::{DNSClass, Name, RData, Record, RecordSet, RecordType},
    },
    server::RequestInfo,
    store::{
        in_memory::InMemoryAuthority,
        sqlite::{Journal, SqliteConfig},
    },
};
#[cfg(feature = "dnssec")]
use crate::{
    authority::{DnssecAuthority, UpdateRequest},
    client::rr::dnssec::{DnsSecResult, SigSigner},
    proto::rr::dnssec::rdata::key::KEY,
};

/// SqliteAuthority is responsible for storing the resource records for a particular zone.
///
/// Authorities default to DNSClass IN. The ZoneType specifies if this should be treated as the
/// start of authority for the zone, is a Secondary, or a cached zone.
#[allow(dead_code)]
pub struct SqliteAuthority {
    in_memory: InMemoryAuthority,
    journal: Mutex<Option<Journal>>,
    allow_update: bool,
    is_dnssec_enabled: bool,
}

impl SqliteAuthority {
    /// Creates a new Authority.
    ///
    /// # Arguments
    ///
    /// * `in_memory` - InMemoryAuthority for all records.
    /// * `allow_update` - If true, then this zone accepts dynamic updates.
    /// * `is_dnssec_enabled` - If true, then the zone will sign the zone with all registered keys,
    ///                         (see `add_zone_signing_key()`)
    ///
    /// # Return value
    ///
    /// The new `Authority`.
    pub fn new(in_memory: InMemoryAuthority, allow_update: bool, is_dnssec_enabled: bool) -> Self {
        Self {
            in_memory,
            journal: Mutex::new(None),
            allow_update,
            is_dnssec_enabled,
        }
    }

    /// load the authority from the configuration
    pub async fn try_from_config(
        origin: Name,
        zone_type: ZoneType,
        allow_axfr: bool,
        enable_dnssec: bool,
        root_dir: Option<&Path>,
        config: &SqliteConfig,
    ) -> Result<Self, String> {
        use crate::store::file::{FileAuthority, FileConfig};

        let zone_name: Name = origin;

        let root_zone_dir = root_dir.map(PathBuf::from).unwrap_or_else(PathBuf::new);

        // to be compatible with previous versions, the extension might be zone, not jrnl
        let journal_path: PathBuf = root_zone_dir.join(&config.journal_file_path);
        let zone_path: PathBuf = root_zone_dir.join(&config.zone_file_path);

        // load the zone
        if journal_path.exists() {
            info!("recovering zone from journal: {:?}", journal_path);
            let journal = Journal::from_file(&journal_path)
                .map_err(|e| format!("error opening journal: {:?}: {}", journal_path, e))?;

            let in_memory = InMemoryAuthority::empty(zone_name.clone(), zone_type, allow_axfr);
            let mut authority = Self::new(in_memory, config.allow_update, enable_dnssec);

            authority
                .recover_with_journal(&journal)
                .await
                .map_err(|e| format!("error recovering from journal: {}", e))?;

            authority.set_journal(journal).await;
            info!("recovered zone: {}", zone_name);

            Ok(authority)
        } else if zone_path.exists() {
            // TODO: deprecate this portion of loading, instantiate the journal through a separate tool
            info!("loading zone file: {:?}", zone_path);

            let file_config = FileConfig {
                zone_file_path: config.zone_file_path.clone(),
            };

            let in_memory = FileAuthority::try_from_config(
                zone_name.clone(),
                zone_type,
                allow_axfr,
                root_dir,
                &file_config,
            )?
            .unwrap();

            let mut authority = Self::new(in_memory, config.allow_update, enable_dnssec);

            // if dynamic update is enabled, enable the journal
            info!("creating new journal: {:?}", journal_path);
            let journal = Journal::from_file(&journal_path)
                .map_err(|e| format!("error creating journal {:?}: {}", journal_path, e))?;

            authority.set_journal(journal).await;

            // preserve to the new journal, i.e. we just loaded the zone from disk, start the journal
            authority
                .persist_to_journal()
                .await
                .map_err(|e| format!("error persisting to journal {:?}: {}", journal_path, e))?;

            info!("zone file loaded: {}", zone_name);
            Ok(authority)
        } else {
            Err(format!(
                "no zone file or journal defined at: {:?}",
                zone_path
            ))
        }
    }

    /// Recovers the zone from a Journal, returns an error on failure to recover the zone.
    ///
    /// # Arguments
    ///
    /// * `journal` - the journal from which to load the persisted zone.
    pub async fn recover_with_journal(&mut self, journal: &Journal) -> PersistenceResult<()> {
        assert!(
            self.in_memory.records_get_mut().is_empty(),
            "records should be empty during a recovery"
        );

        info!("recovering from journal");
        for record in journal.iter() {
            // AXFR is special, it is used to mark the dump of a full zone.
            //  when recovering, if an AXFR is encountered, we should remove all the records in the
            //  authority.
            if record.rr_type() == RecordType::AXFR {
                self.in_memory.clear();
            } else if let Err(error) = self.update_records(&[record], false).await {
                return Err(PersistenceErrorKind::Recovery(error.to_str()).into());
            }
        }

        Ok(())
    }

    /// Persist the state of the current zone to the journal, does nothing if there is no associated
    ///  Journal.
    ///
    /// Returns an error if there was an issue writing to the persistence layer.
    pub async fn persist_to_journal(&self) -> PersistenceResult<()> {
        if let Some(journal) = self.journal.lock().await.as_ref() {
            let serial = self.in_memory.serial().await;

            info!("persisting zone to journal at SOA.serial: {}", serial);

            // TODO: THIS NEEDS TO BE IN A TRANSACTION!!!
            journal.insert_record(serial, Record::new().set_rr_type(RecordType::AXFR))?;

            for rr_set in self.in_memory.records().await.values() {
                // TODO: should we preserve rr_sets or not?
                for record in rr_set.records_without_rrsigs() {
                    journal.insert_record(serial, record)?;
                }
            }

            // TODO: COMMIT THE TRANSACTION!!!
        }

        Ok(())
    }

    /// Associate a backing Journal with this Authority for Updatable zones
    pub async fn set_journal(&mut self, journal: Journal) {
        *self.journal.lock().await = Some(journal);
    }

    /// Returns the associated Journal
    #[cfg(any(test, feature = "testing"))]
    #[cfg_attr(docsrs, doc(cfg(feature = "testing")))]
    pub async fn journal(&self) -> impl Deref<Target = Option<Journal>> + '_ {
        self.journal.lock().await
    }

    /// Enables the zone for dynamic DNS updates
    pub fn set_allow_update(&mut self, allow_update: bool) {
        self.allow_update = allow_update;
    }

    /// Get serial
    #[cfg(any(test, feature = "testing"))]
    #[cfg_attr(docsrs, doc(cfg(feature = "testing")))]
    pub async fn serial(&self) -> u32 {
        self.in_memory.serial().await
    }

    /// [RFC 2136](https://tools.ietf.org/html/rfc2136), DNS Update, April 1997
    ///
    /// ```text
    ///
    /// 3.2 - Process Prerequisite Section
    ///
    ///   Next, the Prerequisite Section is checked to see that all
    ///   prerequisites are satisfied by the current state of the zone.  Using
    ///   the definitions expressed in Section 1.2, if any RR's NAME is not
    ///   within the zone specified in the Zone Section, signal NOTZONE to the
    ///   requestor.
    ///
    /// 3.2.1. For RRs in this section whose CLASS is ANY, test to see that
    ///   TTL and RDLENGTH are both zero (0), else signal FORMERR to the
    ///   requestor.  If TYPE is ANY, test to see that there is at least one RR
    ///   in the zone whose NAME is the same as that of the Prerequisite RR,
    ///   else signal NXDOMAIN to the requestor.  If TYPE is not ANY, test to
    ///   see that there is at least one RR in the zone whose NAME and TYPE are
    ///   the same as that of the Prerequisite RR, else signal NXRRSET to the
    ///   requestor.
    ///
    /// 3.2.2. For RRs in this section whose CLASS is NONE, test to see that
    ///   the TTL and RDLENGTH are both zero (0), else signal FORMERR to the
    ///   requestor.  If the TYPE is ANY, test to see that there are no RRs in
    ///   the zone whose NAME is the same as that of the Prerequisite RR, else
    ///   signal YXDOMAIN to the requestor.  If the TYPE is not ANY, test to
    ///   see that there are no RRs in the zone whose NAME and TYPE are the
    ///   same as that of the Prerequisite RR, else signal YXRRSET to the
    ///   requestor.
    ///
    /// 3.2.3. For RRs in this section whose CLASS is the same as the ZCLASS,
    ///   test to see that the TTL is zero (0), else signal FORMERR to the
    ///   requestor.  Then, build an RRset for each unique <NAME,TYPE> and
    ///   compare each resulting RRset for set equality (same members, no more,
    ///   no less) with RRsets in the zone.  If any Prerequisite RRset is not
    ///   entirely and exactly matched by a zone RRset, signal NXRRSET to the
    ///   requestor.  If any RR in this section has a CLASS other than ZCLASS
    ///   or NONE or ANY, signal FORMERR to the requestor.
    ///
    /// 3.2.4 - Table Of Metavalues Used In Prerequisite Section
    ///
    ///   CLASS    TYPE     RDATA    Meaning
    ///   ------------------------------------------------------------
    ///   ANY      ANY      empty    Name is in use
    ///   ANY      rrset    empty    RRset exists (value independent)
    ///   NONE     ANY      empty    Name is not in use
    ///   NONE     rrset    empty    RRset does not exist
    ///   zone     rrset    rr       RRset exists (value dependent)
    /// ```
    pub async fn verify_prerequisites(&self, pre_requisites: &[Record]) -> UpdateResult<()> {
        //   3.2.5 - Pseudocode for Prerequisite Section Processing
        //
        //      for rr in prerequisites
        //           if (rr.ttl != 0)
        //                return (FORMERR)
        //           if (zone_of(rr.name) != ZNAME)
        //                return (NOTZONE);
        //           if (rr.class == ANY)
        //                if (rr.rdlength != 0)
        //                     return (FORMERR)
        //                if (rr.type == ANY)
        //                     if (!zone_name<rr.name>)
        //                          return (NXDOMAIN)
        //                else
        //                     if (!zone_rrset<rr.name, rr.type>)
        //                          return (NXRRSET)
        //           if (rr.class == NONE)
        //                if (rr.rdlength != 0)
        //                     return (FORMERR)
        //                if (rr.type == ANY)
        //                     if (zone_name<rr.name>)
        //                          return (YXDOMAIN)
        //                else
        //                     if (zone_rrset<rr.name, rr.type>)
        //                          return (YXRRSET)
        //           if (rr.class == zclass)
        //                temp<rr.name, rr.type> += rr
        //           else
        //                return (FORMERR)
        //
        //      for rrset in temp
        //           if (zone_rrset<rrset.name, rrset.type> != rrset)
        //                return (NXRRSET)
        for require in pre_requisites {
            let required_name = LowerName::from(require.name());

            if require.ttl() != 0 {
                warn!("ttl must be 0 for: {:?}", require);
                return Err(ResponseCode::FormErr);
            }

            let origin = self.origin();
            if !origin.zone_of(&require.name().into()) {
                warn!("{} is not a zone_of {}", require.name(), origin);
                return Err(ResponseCode::NotZone);
            }

            match require.dns_class() {
                DNSClass::ANY => {
                    if let None | Some(RData::NULL(..)) = require.data() {
                        match require.rr_type() {
                            // ANY      ANY      empty    Name is in use
                            RecordType::ANY => {
                                if self
                                    .lookup(
                                        &required_name,
                                        RecordType::ANY,
                                        LookupOptions::default(),
                                    )
                                    .await
                                    .unwrap_or_default()
                                    .was_empty()
                                {
                                    return Err(ResponseCode::NXDomain);
                                } else {
                                    continue;
                                }
                            }
                            // ANY      rrset    empty    RRset exists (value independent)
                            rrset => {
                                if self
                                    .lookup(&required_name, rrset, LookupOptions::default())
                                    .await
                                    .unwrap_or_default()
                                    .was_empty()
                                {
                                    return Err(ResponseCode::NXRRSet);
                                } else {
                                    continue;
                                }
                            }
                        }
                    } else {
                        return Err(ResponseCode::FormErr);
                    }
                }
                DNSClass::NONE => {
                    if let None | Some(RData::NULL(..)) = require.data() {
                        match require.rr_type() {
                            // NONE     ANY      empty    Name is not in use
                            RecordType::ANY => {
                                if !self
                                    .lookup(
                                        &required_name,
                                        RecordType::ANY,
                                        LookupOptions::default(),
                                    )
                                    .await
                                    .unwrap_or_default()
                                    .was_empty()
                                {
                                    return Err(ResponseCode::YXDomain);
                                } else {
                                    continue;
                                }
                            }
                            // NONE     rrset    empty    RRset does not exist
                            rrset => {
                                if !self
                                    .lookup(&required_name, rrset, LookupOptions::default())
                                    .await
                                    .unwrap_or_default()
                                    .was_empty()
                                {
                                    return Err(ResponseCode::YXRRSet);
                                } else {
                                    continue;
                                }
                            }
                        }
                    } else {
                        return Err(ResponseCode::FormErr);
                    }
                }
                class if class == self.in_memory.class() =>
                // zone     rrset    rr       RRset exists (value dependent)
                {
                    if !self
                        .lookup(&required_name, require.rr_type(), LookupOptions::default())
                        .await
                        .unwrap_or_default()
                        .iter()
                        .any(|rr| rr == require)
                    {
                        return Err(ResponseCode::NXRRSet);
                    } else {
                        continue;
                    }
                }
                _ => return Err(ResponseCode::FormErr),
            }
        }

        // if we didn't bail everything checked out...
        Ok(())
    }

    /// [RFC 2136](https://tools.ietf.org/html/rfc2136), DNS Update, April 1997
    ///
    /// ```text
    ///
    /// 3.3 - Check Requestor's Permissions
    ///
    /// 3.3.1. Next, the requestor's permission to update the RRs named in
    ///   the Update Section may be tested in an implementation dependent
    ///   fashion or using mechanisms specified in a subsequent Secure DNS
    ///   Update protocol.  If the requestor does not have permission to
    ///   perform these updates, the server may write a warning message in its
    ///   operations log, and may either signal REFUSED to the requestor, or
    ///   ignore the permission problem and proceed with the update.
    ///
    /// 3.3.2. While the exact processing is implementation defined, if these
    ///   verification activities are to be performed, this is the point in the
    ///   server's processing where such performance should take place, since
    ///   if a REFUSED condition is encountered after an update has been
    ///   partially applied, it will be necessary to undo the partial update
    ///   and restore the zone to its original state before answering the
    ///   requestor.
    /// ```
    ///
    #[cfg(feature = "dnssec")]
    #[cfg_attr(docsrs, doc(cfg(feature = "dnssec")))]
    #[allow(clippy::blocks_in_if_conditions)]
    pub async fn authorize(&self, update_message: &MessageRequest) -> UpdateResult<()> {
        use tracing::debug;

        use crate::client::rr::rdata::DNSSECRData;
        use crate::proto::rr::dnssec::Verifier;

        // 3.3.3 - Pseudocode for Permission Checking
        //
        //      if (security policy exists)
        //           if (this update is not permitted)
        //                if (local option)
        //                     log a message about permission problem
        //                if (local option)
        //                     return (REFUSED)

        // does this authority allow_updates?
        if !self.allow_update {
            warn!(
                "update attempted on non-updatable Authority: {}",
                self.origin()
            );
            return Err(ResponseCode::Refused);
        }

        // verify sig0, currently the only authorization that is accepted.
        let sig0s: &[Record] = update_message.sig0();
        debug!("authorizing with: {:?}", sig0s);
        if !sig0s.is_empty() {
            let mut found_key = false;
            for sig in sig0s.iter().filter_map(|sig0| {
                sig0.data()
                    .and_then(RData::as_dnssec)
                    .and_then(DNSSECRData::as_sig)
            }) {
                let name = LowerName::from(sig.signer_name());
                let keys = self
                    .lookup(&name, RecordType::KEY, LookupOptions::default())
                    .await;

                let keys = match keys {
                    Ok(keys) => keys,
                    Err(_) => continue, // error trying to lookup a key by that name, try the next one.
                };

                debug!("found keys {:?}", keys);
                // TODO: check key usage flags and restrictions
                found_key = keys
                    .iter()
                    .filter_map(|rr_set| {
                        rr_set
                            .data()
                            .and_then(RData::as_dnssec)
                            .and_then(DNSSECRData::as_key)
                    })
                    .any(|key| {
                        key.verify_message(update_message, sig.sig(), sig)
                            .map(|_| {
                                info!("verified sig: {:?} with key: {:?}", sig, key);
                                true
                            })
                            .unwrap_or_else(|_| {
                                debug!("did not verify sig: {:?} with key: {:?}", sig, key);
                                false
                            })
                    });

                if found_key {
                    break; // stop searching for matching keys, we found one
                }
            }

            if found_key {
                return Ok(());
            }
        } else {
            warn!(
                "no sig0 matched registered records: id {}",
                update_message.id()
            );
        }

        // getting here, we will always default to rejecting the request
        //  the code will only ever explicitly return authorized actions.
        Err(ResponseCode::Refused)
    }

    /// [RFC 2136](https://tools.ietf.org/html/rfc2136), DNS Update, April 1997
    ///
    /// ```text
    ///
    /// 3.4 - Process Update Section
    ///
    ///   Next, the Update Section is processed as follows.
    ///
    /// 3.4.1 - Prescan
    ///
    ///   The Update Section is parsed into RRs and each RR's CLASS is checked
    ///   to see if it is ANY, NONE, or the same as the Zone Class, else signal
    ///   a FORMERR to the requestor.  Using the definitions in Section 1.2,
    ///   each RR's NAME must be in the zone specified by the Zone Section,
    ///   else signal NOTZONE to the requestor.
    ///
    /// 3.4.1.2. For RRs whose CLASS is not ANY, check the TYPE and if it is
    ///   ANY, AXFR, MAILA, MAILB, or any other QUERY metatype, or any
    ///   unrecognized type, then signal FORMERR to the requestor.  For RRs
    ///   whose CLASS is ANY or NONE, check the TTL to see that it is zero (0),
    ///   else signal a FORMERR to the requestor.  For any RR whose CLASS is
    ///   ANY, check the RDLENGTH to make sure that it is zero (0) (that is,
    ///   the RDATA field is empty), and that the TYPE is not AXFR, MAILA,
    ///   MAILB, or any other QUERY metatype besides ANY, or any unrecognized
    ///   type, else signal FORMERR to the requestor.
    /// ```
    #[allow(clippy::unused_unit)]
    pub async fn pre_scan(&self, records: &[Record]) -> UpdateResult<()> {
        // 3.4.1.3 - Pseudocode For Update Section Prescan
        //
        //      [rr] for rr in updates
        //           if (zone_of(rr.name) != ZNAME)
        //                return (NOTZONE);
        //           if (rr.class == zclass)
        //                if (rr.type & ANY|AXFR|MAILA|MAILB)
        //                     return (FORMERR)
        //           elsif (rr.class == ANY)
        //                if (rr.ttl != 0 || rr.rdlength != 0
        //                    || rr.type & AXFR|MAILA|MAILB)
        //                     return (FORMERR)
        //           elsif (rr.class == NONE)
        //                if (rr.ttl != 0 || rr.type & ANY|AXFR|MAILA|MAILB)
        //                     return (FORMERR)
        //           else
        //                return (FORMERR)
        for rr in records {
            if !self.origin().zone_of(&rr.name().into()) {
                return Err(ResponseCode::NotZone);
            }

            let class: DNSClass = rr.dns_class();
            if class == self.in_memory.class() {
                match rr.rr_type() {
                    RecordType::ANY | RecordType::AXFR | RecordType::IXFR => {
                        return Err(ResponseCode::FormErr);
                    }
                    _ => (),
                }
            } else {
                match class {
                    DNSClass::ANY => {
                        if rr.ttl() != 0 {
                            return Err(ResponseCode::FormErr);
                        }
                        if let None | Some(RData::NULL(..)) = rr.data() {
                            ()
                        } else {
                            return Err(ResponseCode::FormErr);
                        }
                        match rr.rr_type() {
                            RecordType::AXFR | RecordType::IXFR => {
                                return Err(ResponseCode::FormErr);
                            }
                            _ => (),
                        }
                    }
                    DNSClass::NONE => {
                        if rr.ttl() != 0 {
                            return Err(ResponseCode::FormErr);
                        }
                        match rr.rr_type() {
                            RecordType::ANY | RecordType::AXFR | RecordType::IXFR => {
                                return Err(ResponseCode::FormErr);
                            }
                            _ => (),
                        }
                    }
                    _ => return Err(ResponseCode::FormErr),
                }
            }
        }

        Ok(())
    }

    /// Updates the specified records according to the update section.
    ///
    /// [RFC 2136](https://tools.ietf.org/html/rfc2136), DNS Update, April 1997
    ///
    /// ```text
    ///
    /// 3.4.2.6 - Table Of Metavalues Used In Update Section
    ///
    ///   CLASS    TYPE     RDATA    Meaning
    ///   ---------------------------------------------------------
    ///   ANY      ANY      empty    Delete all RRsets from a name
    ///   ANY      rrset    empty    Delete an RRset
    ///   NONE     rrset    rr       Delete an RR from an RRset
    ///   zone     rrset    rr       Add to an RRset
    /// ```
    ///
    /// # Arguments
    ///
    /// * `records` - set of record instructions for update following above rules
    /// * `auto_signing_and_increment` - if true, the zone will sign and increment the SOA, this
    ///                                  should be disabled during recovery.
    pub async fn update_records(
        &self,
        records: &[Record],
        auto_signing_and_increment: bool,
    ) -> UpdateResult<bool> {
        let mut updated = false;
        let serial: u32 = self.in_memory.serial().await;

        // the persistence act as a write-ahead log. The WAL will also be used for recovery of a zone
        //  subsequent to a failure of the server.
        if let Some(ref journal) = *self.journal.lock().await {
            if let Err(error) = journal.insert_records(serial, records) {
                error!("could not persist update records: {}", error);
                return Err(ResponseCode::ServFail);
            }
        }

        // 3.4.2.7 - Pseudocode For Update Section Processing
        //
        //      [rr] for rr in updates
        //           if (rr.class == zclass)
        //                if (rr.type == CNAME)
        //                     if (zone_rrset<rr.name, ~CNAME>)
        //                          next [rr]
        //                elsif (zone_rrset<rr.name, CNAME>)
        //                     next [rr]
        //                if (rr.type == SOA)
        //                     if (!zone_rrset<rr.name, SOA> ||
        //                         zone_rr<rr.name, SOA>.serial > rr.soa.serial)
        //                          next [rr]
        //                for zrr in zone_rrset<rr.name, rr.type>
        //                     if (rr.type == CNAME || rr.type == SOA ||
        //                         (rr.type == WKS && rr.proto == zrr.proto &&
        //                          rr.address == zrr.address) ||
        //                         rr.rdata == zrr.rdata)
        //                          zrr = rr
        //                          next [rr]
        //                zone_rrset<rr.name, rr.type> += rr
        //           elsif (rr.class == ANY)
        //                if (rr.type == ANY)
        //                     if (rr.name == zname)
        //                          zone_rrset<rr.name, ~(SOA|NS)> = Nil
        //                     else
        //                          zone_rrset<rr.name, *> = Nil
        //                elsif (rr.name == zname &&
        //                       (rr.type == SOA || rr.type == NS))
        //                     next [rr]
        //                else
        //                     zone_rrset<rr.name, rr.type> = Nil
        //           elsif (rr.class == NONE)
        //                if (rr.type == SOA)
        //                     next [rr]
        //                if (rr.type == NS && zone_rrset<rr.name, NS> == rr)
        //                     next [rr]
        //                zone_rr<rr.name, rr.type, rr.data> = Nil
        //      return (NOERROR)
        for rr in records {
            let rr_name = LowerName::from(rr.name());
            let rr_key = RrKey::new(rr_name.clone(), rr.rr_type());

            match rr.dns_class() {
                class if class == self.in_memory.class() => {
                    // RFC 2136 - 3.4.2.2. Any Update RR whose CLASS is the same as ZCLASS is added to
                    //  the zone.  In case of duplicate RDATAs (which for SOA RRs is always
                    //  the case, and for WKS RRs is the case if the ADDRESS and PROTOCOL
                    //  fields both match), the Zone RR is replaced by Update RR.  If the
                    //  TYPE is SOA and there is no Zone SOA RR, or the new SOA.SERIAL is
                    //  lower (according to [RFC1982]) than or equal to the current Zone SOA
                    //  RR's SOA.SERIAL, the Update RR is ignored.  In the case of a CNAME
                    //  Update RR and a non-CNAME Zone RRset or vice versa, ignore the CNAME
                    //  Update RR, otherwise replace the CNAME Zone RR with the CNAME Update
                    //  RR.

                    // zone     rrset    rr       Add to an RRset
                    info!("upserting record: {:?}", rr);
                    updated = self.in_memory.upsert(rr.clone(), serial).await || updated;
                }
                DNSClass::ANY => {
                    // This is a delete of entire RRSETs, either many or one. In either case, the spec is clear:
                    match rr.rr_type() {
                        t @ RecordType::SOA | t @ RecordType::NS if rr_name == *self.origin() => {
                            // SOA and NS records are not to be deleted if they are the origin records
                            info!("skipping delete of {:?} see RFC 2136 - 3.4.2.3", t);
                            continue;
                        }
                        RecordType::ANY => {
                            // RFC 2136 - 3.4.2.3. For any Update RR whose CLASS is ANY and whose TYPE is ANY,
                            //   all Zone RRs with the same NAME are deleted, unless the NAME is the
                            //   same as ZNAME in which case only those RRs whose TYPE is other than
                            //   SOA or NS are deleted.

                            // ANY      ANY      empty    Delete all RRsets from a name
                            info!(
                                "deleting all records at name (not SOA or NS at origin): {:?}",
                                rr_name
                            );
                            let origin = self.origin();
                            let to_delete = self
                                .in_memory
                                .records()
                                .await
                                .keys()
                                .filter(|k| {
                                    !((k.record_type == RecordType::SOA
                                        || k.record_type == RecordType::NS)
                                        && k.name != *origin)
                                })
                                .filter(|k| k.name == rr_name)
                                .cloned()
                                .collect::<Vec<RrKey>>();

                            for delete in to_delete {
                                self.in_memory.records_mut().await.remove(&delete);
                                updated = true;
                            }
                        }
                        _ => {
                            // RFC 2136 - 3.4.2.3. For any Update RR whose CLASS is ANY and
                            //   whose TYPE is not ANY all Zone RRs with the same NAME and TYPE are
                            //   deleted, unless the NAME is the same as ZNAME in which case neither
                            //   SOA or NS RRs will be deleted.

                            // ANY      rrset    empty    Delete an RRset
                            if let None | Some(RData::NULL(..)) = rr.data() {
                                let deleted = self.in_memory.records_mut().await.remove(&rr_key);
                                info!("deleted rrset: {:?}", deleted);
                                updated = updated || deleted.is_some();
                            } else {
                                info!("expected empty rdata: {:?}", rr);
                                return Err(ResponseCode::FormErr);
                            }
                        }
                    }
                }
                DNSClass::NONE => {
                    info!("deleting specific record: {:?}", rr);
                    // NONE     rrset    rr       Delete an RR from an RRset
                    if let Some(rrset) = self.in_memory.records_mut().await.get_mut(&rr_key) {
                        // b/c this is an Arc, we need to clone, then remove, and replace the node.
                        let mut rrset_clone: RecordSet = RecordSet::clone(&*rrset);
                        let deleted = rrset_clone.remove(rr, serial);
                        info!("deleted ({}) specific record: {:?}", deleted, rr);
                        updated = updated || deleted;

                        if deleted {
                            *rrset = Arc::new(rrset_clone);
                        }
                    }
                }
                class => {
                    info!("unexpected DNS Class: {:?}", class);
                    return Err(ResponseCode::FormErr);
                }
            }
        }

        // update the serial...
        if updated && auto_signing_and_increment {
            if self.is_dnssec_enabled {
                cfg_if::cfg_if! {
                    if #[cfg(feature = "dnssec")] {
                        self.secure_zone().await.map_err(|e| {
                            error!("failure securing zone: {}", e);
                            ResponseCode::ServFail
                        })?
                    } else {
                        error!("failure securing zone, dnssec feature not enabled");
                        return Err(ResponseCode::ServFail)
                    }
                }
            } else {
                // the secure_zone() function increments the SOA during it's operation, if we're not
                //  dnssec, then we need to do it here...
                self.in_memory.increment_soa_serial().await;
            }
        }

        Ok(updated)
    }
}

impl Deref for SqliteAuthority {
    type Target = InMemoryAuthority;

    fn deref(&self) -> &Self::Target {
        &self.in_memory
    }
}

impl DerefMut for SqliteAuthority {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.in_memory
    }
}

#[async_trait::async_trait]
impl Authority for SqliteAuthority {
    type Lookup = <InMemoryAuthority as Authority>::Lookup;

    /// What type is this zone
    fn zone_type(&self) -> ZoneType {
        self.in_memory.zone_type()
    }

    /// Return true if AXFR is allowed
    fn is_axfr_allowed(&self) -> bool {
        self.in_memory.is_axfr_allowed()
    }

    /// Takes the UpdateMessage, extracts the Records, and applies the changes to the record set.
    ///
    /// [RFC 2136](https://tools.ietf.org/html/rfc2136), DNS Update, April 1997
    ///
    /// ```text
    ///
    /// 3.4 - Process Update Section
    ///
    ///   Next, the Update Section is processed as follows.
    ///
    /// 3.4.2 - Update
    ///
    ///   The Update Section is parsed into RRs and these RRs are processed in
    ///   order.
    ///
    /// 3.4.2.1. If any system failure (such as an out of memory condition,
    ///   or a hardware error in persistent storage) occurs during the
    ///   processing of this section, signal SERVFAIL to the requestor and undo
    ///   all updates applied to the zone during this transaction.
    ///
    /// 3.4.2.2. Any Update RR whose CLASS is the same as ZCLASS is added to
    ///   the zone.  In case of duplicate RDATAs (which for SOA RRs is always
    ///   the case, and for WKS RRs is the case if the ADDRESS and PROTOCOL
    ///   fields both match), the Zone RR is replaced by Update RR.  If the
    ///   TYPE is SOA and there is no Zone SOA RR, or the new SOA.SERIAL is
    ///   lower (according to [RFC1982]) than or equal to the current Zone SOA
    ///   RR's SOA.SERIAL, the Update RR is ignored.  In the case of a CNAME
    ///   Update RR and a non-CNAME Zone RRset or vice versa, ignore the CNAME
    ///   Update RR, otherwise replace the CNAME Zone RR with the CNAME Update
    ///   RR.
    ///
    /// 3.4.2.3. For any Update RR whose CLASS is ANY and whose TYPE is ANY,
    ///   all Zone RRs with the same NAME are deleted, unless the NAME is the
    ///   same as ZNAME in which case only those RRs whose TYPE is other than
    ///   SOA or NS are deleted.  For any Update RR whose CLASS is ANY and
    ///   whose TYPE is not ANY all Zone RRs with the same NAME and TYPE are
    ///   deleted, unless the NAME is the same as ZNAME in which case neither
    ///   SOA or NS RRs will be deleted.
    ///
    /// 3.4.2.4. For any Update RR whose class is NONE, any Zone RR whose
    ///   NAME, TYPE, RDATA and RDLENGTH are equal to the Update RR is deleted,
    ///   unless the NAME is the same as ZNAME and either the TYPE is SOA or
    ///   the TYPE is NS and the matching Zone RR is the only NS remaining in
    ///   the RRset, in which case this Update RR is ignored.
    ///
    /// 3.4.2.5. Signal NOERROR to the requestor.
    /// ```
    ///
    /// # Arguments
    ///
    /// * `update` - The `UpdateMessage` records will be extracted and used to perform the update
    ///              actions as specified in the above RFC.
    ///
    /// # Return value
    ///
    /// true if any of additions, updates or deletes were made to the zone, false otherwise. Err is
    ///  returned in the case of bad data, etc.
    #[cfg(feature = "dnssec")]
    async fn update(&self, update: &MessageRequest) -> UpdateResult<bool> {
        //let this = &mut self.in_memory.lock().await;
        // the spec says to authorize after prereqs, seems better to auth first.
        self.authorize(update).await?;
        self.verify_prerequisites(update.prerequisites()).await?;
        self.pre_scan(update.updates()).await?;

        self.update_records(update.updates(), true).await
    }

    /// Always fail when DNSSEC is disabled.
    #[cfg(not(feature = "dnssec"))]
    async fn update(&self, _update: &MessageRequest) -> UpdateResult<bool> {
        Err(ResponseCode::NotImp)
    }

    /// Get the origin of this zone, i.e. example.com is the origin for www.example.com
    fn origin(&self) -> &LowerName {
        self.in_memory.origin()
    }

    /// Looks up all Resource Records matching the giving `Name` and `RecordType`.
    ///
    /// # Arguments
    ///
    /// * `name` - The `Name`, label, to lookup.
    /// * `rtype` - The `RecordType`, to lookup. `RecordType::ANY` will return all records matching
    ///             `name`. `RecordType::AXFR` will return all record types except `RecordType::SOA`
    ///             due to the requirements that on zone transfers the `RecordType::SOA` must both
    ///             precede and follow all other records.
    /// * `is_secure` - If the DO bit is set on the EDNS OPT record, then return RRSIGs as well.
    ///
    /// # Return value
    ///
    /// None if there are no matching records, otherwise a `Vec` containing the found records.
    async fn lookup(
        &self,
        name: &LowerName,
        rtype: RecordType,
        lookup_options: LookupOptions,
    ) -> Result<Self::Lookup, LookupError> {
        self.in_memory.lookup(name, rtype, lookup_options).await
    }

    async fn search(
        &self,
        request_info: RequestInfo<'_>,
        lookup_options: LookupOptions,
    ) -> Result<Self::Lookup, LookupError> {
        self.in_memory.search(request_info, lookup_options).await
    }

    /// Return the NSEC records based on the given name
    ///
    /// # Arguments
    ///
    /// * `name` - given this name (i.e. the lookup name), return the NSEC record that is less than
    ///            this
    /// * `is_secure` - if true then it will return RRSIG records as well
    async fn get_nsec_records(
        &self,
        name: &LowerName,
        lookup_options: LookupOptions,
    ) -> Result<Self::Lookup, LookupError> {
        self.in_memory.get_nsec_records(name, lookup_options).await
    }
}

#[cfg(feature = "dnssec")]
#[cfg_attr(docsrs, doc(cfg(feature = "dnssec")))]
#[async_trait::async_trait]
impl DnssecAuthority for SqliteAuthority {
    async fn add_update_auth_key(&self, name: Name, key: KEY) -> DnsSecResult<()> {
        self.in_memory.add_update_auth_key(name, key).await
    }

    /// By adding a secure key, this will implicitly enable dnssec for the zone.
    ///
    /// # Arguments
    ///
    /// * `signer` - Signer with associated private key
    async fn add_zone_signing_key(&self, signer: SigSigner) -> DnsSecResult<()> {
        self.in_memory.add_zone_signing_key(signer).await
    }

    /// (Re)generates the nsec records, increments the serial number and signs the zone
    async fn secure_zone(&self) -> DnsSecResult<()> {
        self.in_memory.secure_zone().await
    }
}

#[cfg(test)]
mod tests {
    use crate::store::sqlite::SqliteAuthority;

    #[test]
    fn test_is_send_sync() {
        fn send_sync<T: Send + Sync>() -> bool {
            true
        }

        assert!(send_sync::<SqliteAuthority>());
    }
}