rec: Validate lack of DS record

[thirdparty/pdns.git] / pdns / syncres.cc

/*
 * This file is part of PowerDNS or dnsdist.
 * Copyright -- PowerDNS.COM B.V. and its contributors
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * In addition, for the avoidance of any doubt, permission is granted to
 * link this program with OpenSSL and to (re)distribute the binaries
 * produced as the result of such linking.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "arguments.hh"
#include "cachecleaner.hh"
#include "dns_random.hh"
#include "dnsparser.hh"
#include "dnsrecords.hh"
#include "ednssubnet.hh"
#include "logger.hh"
#include "lua-recursor4.hh"
#include "rec-lua-conf.hh"
#include "syncres.hh"
#include "validate-recursor.hh"

thread_local SyncRes::ThreadLocalStorage SyncRes::t_sstorage;

std::unordered_set<DNSName> SyncRes::s_delegationOnly;
std::unique_ptr<NetmaskGroup> SyncRes::s_dontQuery{nullptr};
NetmaskGroup SyncRes::s_ednssubnets;
SuffixMatchNode SyncRes::s_ednsdomains;
string SyncRes::s_serverID;
SyncRes::LogMode SyncRes::s_lm;

unsigned int SyncRes::s_maxnegttl;
unsigned int SyncRes::s_maxcachettl;
unsigned int SyncRes::s_maxqperq;
unsigned int SyncRes::s_maxtotusec;
unsigned int SyncRes::s_maxdepth;
unsigned int SyncRes::s_minimumTTL;
unsigned int SyncRes::s_packetcachettl;
unsigned int SyncRes::s_packetcacheservfailttl;
unsigned int SyncRes::s_serverdownmaxfails;
unsigned int SyncRes::s_serverdownthrottletime;
std::atomic<uint64_t> SyncRes::s_queries;
std::atomic<uint64_t> SyncRes::s_outgoingtimeouts;
std::atomic<uint64_t> SyncRes::s_outgoing4timeouts;
std::atomic<uint64_t> SyncRes::s_outgoing6timeouts;
std::atomic<uint64_t> SyncRes::s_outqueries;
std::atomic<uint64_t> SyncRes::s_tcpoutqueries;
std::atomic<uint64_t> SyncRes::s_throttledqueries;
std::atomic<uint64_t> SyncRes::s_dontqueries;
std::atomic<uint64_t> SyncRes::s_nodelegated;
std::atomic<uint64_t> SyncRes::s_unreachables;
uint8_t SyncRes::s_ecsipv4limit;
uint8_t SyncRes::s_ecsipv6limit;
bool SyncRes::s_doIPv6;
bool SyncRes::s_nopacketcache;
bool SyncRes::s_rootNXTrust;
bool SyncRes::s_noEDNS;

#define LOG(x) if(d_lm == Log) { L <<Logger::Warning << x; } else if(d_lm == Store) { d_trace << x; }

static void accountAuthLatency(int usec, int family)
{
  if(family == AF_INET) {
    if(usec < 1000)
      g_stats.auth4Answers0_1++;
    else if(usec < 10000)
      g_stats.auth4Answers1_10++;
    else if(usec < 100000)
      g_stats.auth4Answers10_100++;
    else if(usec < 1000000)
      g_stats.auth4Answers100_1000++;
    else
      g_stats.auth4AnswersSlow++;
  } else  {
    if(usec < 1000)
      g_stats.auth6Answers0_1++;
    else if(usec < 10000)
      g_stats.auth6Answers1_10++;
    else if(usec < 100000)
      g_stats.auth6Answers10_100++;
    else if(usec < 1000000)
      g_stats.auth6Answers100_1000++;
    else
      g_stats.auth6AnswersSlow++;
  }

}


SyncRes::SyncRes(const struct timeval& now) :  d_outqueries(0), d_tcpoutqueries(0), d_throttledqueries(0), d_timeouts(0), d_unreachables(0),
                                               d_totUsec(0), d_now(now),
                                               d_cacheonly(false), d_doDNSSEC(false), d_doEDNS0(false), d_lm(s_lm)
                                                 
{ 
}

/** everything begins here - this is the entry point just after receiving a packet */
int SyncRes::beginResolve(const DNSName &qname, const QType &qtype, uint16_t qclass, vector<DNSRecord>&ret)
{
  vState state = Indeterminate;
  s_queries++;
  d_wasVariable=false;
  d_wasOutOfBand=false;

  if (doSpecialNamesResolve(qname, qtype, qclass, ret)) {
    d_queryValidationState = Secure;
    return 0;
  }

  if( (qtype.getCode() == QType::AXFR) || (qtype.getCode() == QType::IXFR))
    return -1;

  if(qclass==QClass::ANY)
    qclass=QClass::IN;
  else if(qclass!=QClass::IN)
    return -1;

  set<GetBestNSAnswer> beenthere;
  int res=doResolve(qname, qtype, ret, 0, beenthere, state);
  d_queryValidationState = state;
  return res;
}

/*! Handles all special, built-in names
 * Fills ret with an answer and returns true if it handled the query.
 *
 * Handles the following queries (and their ANY variants):
 *
 * - localhost. IN A
 * - localhost. IN AAAA
 * - 1.0.0.127.in-addr.arpa. IN PTR
 * - 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. IN PTR
 * - version.bind. CH TXT
 * - version.pdns. CH TXT
 * - id.server. CH TXT
 */
bool SyncRes::doSpecialNamesResolve(const DNSName &qname, const QType &qtype, const uint16_t qclass, vector<DNSRecord> &ret)
{
  static const DNSName arpa("1.0.0.127.in-addr.arpa."), ip6_arpa("1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa."),
    localhost("localhost."), versionbind("version.bind."), idserver("id.server."), versionpdns("version.pdns.");

  bool handled = false;
  vector<pair<QType::typeenum, string> > answers;

  if ((qname == arpa || qname == ip6_arpa) &&
      qclass == QClass::IN) {
    handled = true;
    if (qtype == QType::PTR || qtype == QType::ANY)
      answers.push_back({QType::PTR, "localhost."});
  }

  if (qname == localhost &&
      qclass == QClass::IN) {
    handled = true;
    if (qtype == QType::A || qtype == QType::ANY)
      answers.push_back({QType::A, "127.0.0.1"});
    if (qtype == QType::AAAA || qtype == QType::ANY)
      answers.push_back({QType::AAAA, "::1"});
  }

  if ((qname == versionbind || qname == idserver || qname == versionpdns) &&
      qclass == QClass::CHAOS) {
    handled = true;
    if (qtype == QType::TXT || qtype == QType::ANY) {
      if(qname == versionbind || qname == versionpdns)
        answers.push_back({QType::TXT, "\""+::arg()["version-string"]+"\""});
      else
        answers.push_back({QType::TXT, "\""+s_serverID+"\""});
    }
  }

  if (handled && !answers.empty()) {
    ret.clear();
    d_wasOutOfBand=true;

    DNSRecord dr;
    dr.d_name = qname;
    dr.d_place = DNSResourceRecord::ANSWER;
    dr.d_class = qclass;
    dr.d_ttl = 86400;
    for (const auto& ans : answers) {
      dr.d_type = ans.first;
      dr.d_content = DNSRecordContent::mastermake(ans.first, qclass, ans.second);
      ret.push_back(dr);
    }
  }

  return handled;
}


//! This is the 'out of band resolver', in other words, the authoritative server
void SyncRes::AuthDomain::addSOA(std::vector<DNSRecord>& records) const
{
  SyncRes::AuthDomain::records_t::const_iterator ziter = d_records.find(boost::make_tuple(getName(), QType::SOA));
  if (ziter != d_records.end()) {
    DNSRecord dr = *ziter;
    dr.d_place = DNSResourceRecord::AUTHORITY;
    records.push_back(dr);
  }
  else {
    // cerr<<qname<<": can't find SOA record '"<<getName()<<"' in our zone!"<<endl;
  }
}

int SyncRes::AuthDomain::getRecords(const DNSName& qname, uint16_t qtype, std::vector<DNSRecord>& records) const
{
  int result = RCode::NoError;
  records.clear();

  // partial lookup
  std::pair<records_t::const_iterator,records_t::const_iterator> range = d_records.equal_range(tie(qname));

  SyncRes::AuthDomain::records_t::const_iterator ziter;
  bool somedata = false;

  for(ziter = range.first; ziter != range.second; ++ziter) {
    somedata = true;

    if(qtype == QType::ANY || ziter->d_type == qtype || ziter->d_type == QType::CNAME) {
      // let rest of nameserver do the legwork on this one
      records.push_back(*ziter);
    }
    else if (ziter->d_type == QType::NS && ziter->d_name.countLabels() > getName().countLabels()) {
      // we hit a delegation point!
      DNSRecord dr = *ziter;
      dr.d_place=DNSResourceRecord::AUTHORITY;
      records.push_back(dr);
    }
  }

  if (!records.empty()) {
    /* We have found an exact match, we're done */
    // cerr<<qname<<": exact match in zone '"<<getName()<<"'"<<endl;
    return result;
  }

  if (somedata) {
    /* We have records for that name, but not of the wanted qtype */
    // cerr<<qname<<": found record in '"<<getName()<<"', but nothing of the right type, sending SOA"<<endl;
    addSOA(records);

    return result;
  }

  // cerr<<qname<<": nothing found so far in '"<<getName()<<"', trying wildcards"<<endl;
  DNSName wcarddomain(qname);
  while(wcarddomain != getName() && wcarddomain.chopOff()) {
    // cerr<<qname<<": trying '*."<<wcarddomain<<"' in "<<getName()<<endl;
    range = d_records.equal_range(boost::make_tuple(g_wildcarddnsname + wcarddomain));
    if (range.first==range.second)
      continue;

    for(ziter = range.first; ziter != range.second; ++ziter) {
      DNSRecord dr = *ziter;
      // if we hit a CNAME, just answer that - rest of recursor will do the needful & follow
      if(dr.d_type == qtype || qtype == QType::ANY || dr.d_type == QType::CNAME) {
        dr.d_name = qname;
        dr.d_place = DNSResourceRecord::ANSWER;
        records.push_back(dr);
      }
    }

    if (records.empty()) {
      addSOA(records);
    }

    // cerr<<qname<<": in '"<<getName()<<"', had wildcard match on '*."<<wcarddomain<<"'"<<endl;
    return result;
  }

  /* Nothing for this name, no wildcard, let's see if there is some NS */
  DNSName nsdomain(qname);
  while (nsdomain.chopOff() && nsdomain != getName()) {
    range = d_records.equal_range(boost::make_tuple(nsdomain,QType::NS));
    if(range.first == range.second)
      continue;

    for(ziter = range.first; ziter != range.second; ++ziter) {
      DNSRecord dr = *ziter;
      dr.d_place = DNSResourceRecord::AUTHORITY;
      records.push_back(dr);
    }
  }

  if(records.empty()) {
    // cerr<<qname<<": no NS match in zone '"<<getName()<<"' either, handing out SOA"<<endl;
    addSOA(records);
    result = RCode::NXDomain;
  }

  return result;
}

bool SyncRes::doOOBResolve(const AuthDomain& domain, const DNSName &qname, const QType &qtype, vector<DNSRecord>&ret, int& res) const
{
  res = domain.getRecords(qname, qtype.getCode(), ret);
  return true;
}

bool SyncRes::doOOBResolve(const DNSName &qname, const QType &qtype, vector<DNSRecord>&ret, unsigned int depth, int& res)
{
  string prefix;
  if(doLog()) {
    prefix=d_prefix;
    prefix.append(depth, ' ');
  }

  DNSName authdomain(qname);
  domainmap_t::const_iterator iter=getBestAuthZone(&authdomain);
  if(iter==t_sstorage.domainmap->end() || !iter->second.isAuth()) {
    LOG(prefix<<qname<<": auth storage has no zone for this query!"<<endl);
    return false;
  }

  LOG(prefix<<qname<<": auth storage has data, zone='"<<authdomain<<"'"<<endl);
  return doOOBResolve(iter->second, qname, qtype, ret, res);
}

void SyncRes::doEDNSDumpAndClose(int fd)
{
  FILE* fp=fdopen(fd, "w");
  if (!fp) {
    return;
  }
  fprintf(fp,"IP Address\tMode\tMode last updated at\n");
  for(const auto& eds : t_sstorage.ednsstatus) {
    fprintf(fp, "%s\t%d\t%s", eds.first.toString().c_str(), (int)eds.second.mode, ctime(&eds.second.modeSetAt));
  }

  fclose(fp);
}

uint64_t SyncRes::doDumpNSSpeeds(int fd)
{
  FILE* fp=fdopen(dup(fd), "w");
  if(!fp)
    return 0;
  fprintf(fp, "; nsspeed dump from thread follows\n;\n");
  uint64_t count=0;

  for(const auto& i : t_sstorage.nsSpeeds)
  {
    count++;
    fprintf(fp, "%s -> ", i.first.toString().c_str());
    for(const auto& j : i.second.d_collection)
    {
      // typedef vector<pair<ComboAddress, DecayingEwma> > collection_t;
      fprintf(fp, "%s/%f ", j.first.toString().c_str(), j.second.peek());
    }
    fprintf(fp, "\n");
  }
  fclose(fp);
  return count;
}

/* so here is the story. First we complete the full resolution process for a domain name. And only THEN do we decide
   to also do DNSSEC validation, which leads to new queries. To make this simple, we *always* ask for DNSSEC records
   so that if there are RRSIGs for a name, we'll have them.

   However, some hosts simply can't answer questions which ask for DNSSEC. This can manifest itself as:
   * No answer
   * FormErr
   * Nonsense answer

   The cause of "No answer" may be fragmentation, and it is tempting to probe if smaller answers would get through.
   Another cause of "No answer" may simply be a network condition.
   Nonsense answers are a clearer indication this host won't be able to do DNSSEC evah.

   Previous implementations have suffered from turning off DNSSEC questions for an authoritative server based on timeouts. 
   A clever idea is to only turn off DNSSEC if we know a domain isn't signed anyhow. The problem with that really
   clever idea however is that at this point in PowerDNS, we may simply not know that yet. All the DNSSEC thinking happens 
   elsewhere. It may not have happened yet. 

   For now this means we can't be clever, but will turn off DNSSEC if you reply with FormError or gibberish.
*/

int SyncRes::asyncresolveWrapper(const ComboAddress& ip, bool ednsMANDATORY, const DNSName& domain, int type, bool doTCP, bool sendRDQuery, struct timeval* now, boost::optional<Netmask>& srcmask, LWResult* res) const
{
  /* what is your QUEST?
     the goal is to get as many remotes as possible on the highest level of EDNS support
     The levels are:

     0) UNKNOWN Unknown state 
     1) EDNS: Honors EDNS0
     2) EDNSIGNORANT: Ignores EDNS0, gives replies without EDNS0
     3) NOEDNS: Generates FORMERR/NOTIMP on EDNS queries

     Everybody starts out assumed to be '0'.
     If '0', send out EDNS0
        If you FORMERR us, go to '3', 
        If no EDNS in response, go to '2'
     If '1', send out EDNS0
        If FORMERR, downgrade to 3
     If '2', keep on including EDNS0, see what happens
        Same behaviour as 0 
     If '3', send bare queries
  */

  SyncRes::EDNSStatus* ednsstatus;
  ednsstatus = &t_sstorage.ednsstatus[ip]; // does this include port? YES

  if(ednsstatus->modeSetAt && ednsstatus->modeSetAt + 3600 < d_now.tv_sec) {
    *ednsstatus=SyncRes::EDNSStatus();
    //    cerr<<"Resetting EDNS Status for "<<ip.toString()<<endl);
  }

  SyncRes::EDNSStatus::EDNSMode& mode=ednsstatus->mode;
  SyncRes::EDNSStatus::EDNSMode oldmode = mode;
  int EDNSLevel = 0;
  auto luaconfsLocal = g_luaconfs.getLocal();
  ResolveContext ctx;
#ifdef HAVE_PROTOBUF
  ctx.d_initialRequestId = d_initialRequestId;
#endif

  int ret;
  for(int tries = 0; tries < 3; ++tries) {
    //    cerr<<"Remote '"<<ip.toString()<<"' currently in mode "<<mode<<endl;
    
    if(mode==EDNSStatus::NOEDNS) {
      g_stats.noEdnsOutQueries++;
      EDNSLevel = 0; // level != mode
    }
    else if(ednsMANDATORY || mode==EDNSStatus::UNKNOWN || mode==EDNSStatus::EDNSOK || mode==EDNSStatus::EDNSIGNORANT)
      EDNSLevel = 1;

    if (d_asyncResolve) {
      ret = d_asyncResolve(ip, domain, type, doTCP, sendRDQuery, EDNSLevel, now, srcmask, ctx, luaconfsLocal->outgoingProtobufServer, res);
    }
    else {
      ret=asyncresolve(ip, domain, type, doTCP, sendRDQuery, EDNSLevel, now, srcmask, ctx, luaconfsLocal->outgoingProtobufServer, res);
    }
    if(ret < 0) {
      return ret; // transport error, nothing to learn here
    }

    if(ret == 0) { // timeout, not doing anything with it now
      return ret;
    }
    else if(mode==EDNSStatus::UNKNOWN || mode==EDNSStatus::EDNSOK || mode == EDNSStatus::EDNSIGNORANT ) {
      if(res->d_rcode == RCode::FormErr || res->d_rcode == RCode::NotImp)  {
        //      cerr<<"Downgrading to NOEDNS because of "<<RCode::to_s(res->d_rcode)<<" for query to "<<ip.toString()<<" for '"<<domain<<"'"<<endl;
        mode = EDNSStatus::NOEDNS;
        continue;
      }
      else if(!res->d_haveEDNS) {
        if(mode != EDNSStatus::EDNSIGNORANT) {
          mode = EDNSStatus::EDNSIGNORANT;
          //      cerr<<"We find that "<<ip.toString()<<" is an EDNS-ignorer for '"<<domain<<"', moving to mode 3"<<endl;
        }
      }
      else {
        mode = EDNSStatus::EDNSOK;
        //      cerr<<"We find that "<<ip.toString()<<" is EDNS OK!"<<endl;
      }
      
    }
    if(oldmode != mode || !ednsstatus->modeSetAt)
      ednsstatus->modeSetAt=d_now.tv_sec;
    //    cerr<<"Result: ret="<<ret<<", EDNS-level: "<<EDNSLevel<<", haveEDNS: "<<res->d_haveEDNS<<", new mode: "<<mode<<endl;  
    return ret;
  }
  return ret;
}

/*! This function will check the cache and go out to the internet if the answer is not in cache
 *
 * \param qname The name we need an answer for
 * \param qtype
 * \param ret The vector of DNSRecords we need to fill with the answers
 * \param depth The recursion depth we are in
 * \param beenthere
 * \return DNS RCODE or -1 (Error) or -2 (RPZ hit)
 */
int SyncRes::doResolve(const DNSName &qname, const QType &qtype, vector<DNSRecord>&ret, unsigned int depth, set<GetBestNSAnswer>& beenthere, vState& state)
{
  string prefix;
  if(doLog()) {
    prefix=d_prefix;
    prefix.append(depth, ' ');
  }

  LOG(prefix<<qname<<": Wants "<< (d_doDNSSEC ? "" : "NO ") << "DNSSEC processing, "<<(d_requireAuthData ? "" : "NO ")<<"auth data in query for "<<qtype.getName()<<endl);

  state = Indeterminate;

  if(s_maxdepth && depth > s_maxdepth)
    throw ImmediateServFailException("More than "+std::to_string(s_maxdepth)+" (max-recursion-depth) levels of recursion needed while resolving "+qname.toLogString());

  int res=0;

  // This is a difficult way of expressing "this is a normal query", i.e. not getRootNS.
  if(!(d_updatingRootNS && qtype.getCode()==QType::NS && qname.isRoot())) {
    if(d_cacheonly) { // very limited OOB support
      LWResult lwr;
      LOG(prefix<<qname<<": Recursion not requested for '"<<qname<<"|"<<qtype.getName()<<"', peeking at auth/forward zones"<<endl);
      DNSName authname(qname);
      domainmap_t::const_iterator iter=getBestAuthZone(&authname);
      if(iter != t_sstorage.domainmap->end()) {
        if(iter->second.isAuth()) {
          ret.clear();
          d_wasOutOfBand = doOOBResolve(qname, qtype, ret, depth, res);
          return res;
        }
        else {
          const vector<ComboAddress>& servers = iter->second.d_servers;
          const ComboAddress remoteIP = servers.front();
          LOG(prefix<<qname<<": forwarding query to hardcoded nameserver '"<< remoteIP.toStringWithPort()<<"' for zone '"<<authname<<"'"<<endl);

          boost::optional<Netmask> nm;
          res=asyncresolveWrapper(remoteIP, d_doDNSSEC, qname, qtype.getCode(), false, false, &d_now, nm, &lwr);
          // filter out the good stuff from lwr.result()
          if (res == 1) {
            for(const auto& rec : lwr.d_records) {
              if(rec.d_place == DNSResourceRecord::ANSWER)
                ret.push_back(rec);
            }
            return 0;
          }
          else {
            return RCode::ServFail;
          }
        }
      }
    }

    if(!d_skipCNAMECheck && doCNAMECacheCheck(qname,qtype,ret,depth,res,state)) // will reroute us if needed
      return res;

    if(doCacheCheck(qname,qtype,ret,depth,res,state)) // we done
      return res;
  }

  if(d_cacheonly)
    return 0;

  LOG(prefix<<qname<<": No cache hit for '"<<qname<<"|"<<qtype.getName()<<"', trying to find an appropriate NS record"<<endl);

  DNSName subdomain(qname);
  if(qtype == QType::DS) subdomain.chopOff();

  NsSet nsset;
  bool flawedNSSet=false;

  const SyncRes::zonesStates_t cuts = computeZoneCuts(qname, g_rootdnsname, depth);

  // the two retries allow getBestNSNamesFromCache&co to reprime the root
  // hints, in case they ever go missing
  for(int tries=0;tries<2 && nsset.empty();++tries) {
    subdomain=getBestNSNamesFromCache(subdomain, qtype, nsset, &flawedNSSet, depth, beenthere); //  pass beenthere to both occasions
  }

  state = getValidationStatus(cuts, subdomain);

  LOG("Initial validation status for "<<qname<<" inherited from "<<subdomain<<" is "<<vStates[state]<<endl);

  if(!(res=doResolveAt(nsset, subdomain, flawedNSSet, qname, qtype, ret, depth, beenthere, state, cuts)))
    return 0;

  LOG(prefix<<qname<<": failed (res="<<res<<")"<<endl);

  if (res == -2)
    return res;

  return res<0 ? RCode::ServFail : res;
}

#if 0
// for testing purposes
static bool ipv6First(const ComboAddress& a, const ComboAddress& b)
{
  return !(a.sin4.sin_family < a.sin4.sin_family);
}
#endif

/** This function explicitly goes out for A or AAAA addresses
*/
vector<ComboAddress> SyncRes::getAddrs(const DNSName &qname, unsigned int depth, set<GetBestNSAnswer>& beenthere)
{
  typedef vector<DNSRecord> res_t;
  res_t res;

  typedef vector<ComboAddress> ret_t;
  ret_t ret;

  QType type;
  bool oldRequireAuthData = d_requireAuthData;
  d_requireAuthData = false;

  for(int j=1; j<2+s_doIPv6; j++)
  {
    bool done=false;
    switch(j) {
      case 0:
        type = QType::ANY;
        break;
      case 1:
        type = QType::A;
        break;
      case 2:
        type = QType::AAAA;
        break;
    }

    vState newState = Indeterminate;
    if(!doResolve(qname, type, res,depth+1, beenthere, newState) && !res.empty()) {  // this consults cache, OR goes out
      for(res_t::const_iterator i=res.begin(); i!= res.end(); ++i) {
        if(i->d_type == QType::A || i->d_type == QType::AAAA) {
          if(auto rec = std::dynamic_pointer_cast<ARecordContent>(i->d_content))
            ret.push_back(rec->getCA(53));
          else if(auto aaaarec = std::dynamic_pointer_cast<AAAARecordContent>(i->d_content))
            ret.push_back(aaaarec->getCA(53));
          done=true;
        }
      }
    }
    if(done) {
      if(j==1 && s_doIPv6) { // we got an A record, see if we have some AAAA lying around
        vector<DNSRecord> cset;
        if(t_RC->get(d_now.tv_sec, qname, QType(QType::AAAA), false, &cset, d_requestor) > 0) {
          for(auto k=cset.cbegin();k!=cset.cend();++k) {
            if(k->d_ttl > (unsigned int)d_now.tv_sec ) {
              if (auto drc = std::dynamic_pointer_cast<AAAARecordContent>(k->d_content)) {
                ComboAddress ca=drc->getCA(53);
                ret.push_back(ca);
              }
            }
          }
        }
      }
      break;
    }
  }

  d_requireAuthData = oldRequireAuthData;

  if(ret.size() > 1) {
    random_shuffle(ret.begin(), ret.end(), dns_random);

    // move 'best' address for this nameserver name up front
    nsspeeds_t::iterator best = t_sstorage.nsSpeeds.find(qname);

    if(best != t_sstorage.nsSpeeds.end())
      for(ret_t::iterator i=ret.begin(); i != ret.end(); ++i) {
        if(*i==best->second.d_best) {  // got the fastest one
          if(i!=ret.begin()) {
            *i=*ret.begin();
            *ret.begin()=best->second.d_best;
          }
          break;
        }
      }
  }

  return ret;
}

void SyncRes::getBestNSFromCache(const DNSName &qname, const QType& qtype, vector<DNSRecord>& bestns, bool* flawedNSSet, unsigned int depth, set<GetBestNSAnswer>& beenthere)
{
  string prefix;
  DNSName subdomain(qname);
  if(doLog()) {
    prefix=d_prefix;
    prefix.append(depth, ' ');
  }
  bestns.clear();
  bool brokeloop;
  do {
    brokeloop=false;
    LOG(prefix<<qname<<": Checking if we have NS in cache for '"<<subdomain<<"'"<<endl);
    vector<DNSRecord> ns;
    *flawedNSSet = false;

    if(t_RC->get(d_now.tv_sec, subdomain, QType(QType::NS), false, &ns, d_requestor) > 0) {
      for(auto k=ns.cbegin();k!=ns.cend(); ++k) {
        if(k->d_ttl > (unsigned int)d_now.tv_sec ) {
          vector<DNSRecord> aset;

          const DNSRecord& dr=*k;
          auto nrr = getRR<NSRecordContent>(dr);
          if(nrr && (!nrr->getNS().isPartOf(subdomain) || t_RC->get(d_now.tv_sec, nrr->getNS(), s_doIPv6 ? QType(QType::ADDR) : QType(QType::A),
                                                                    false, doLog() ? &aset : nullptr, d_requestor) > 5)) {
            bestns.push_back(dr);
            LOG(prefix<<qname<<": NS (with ip, or non-glue) in cache for '"<<subdomain<<"' -> '"<<nrr->getNS()<<"'"<<endl);
            LOG(prefix<<qname<<": within bailiwick: "<< nrr->getNS().isPartOf(subdomain));
            if(!aset.empty()) {
              LOG(",  in cache, ttl="<<(unsigned int)(((time_t)aset.begin()->d_ttl- d_now.tv_sec ))<<endl);
            }
            else {
              LOG(", not in cache / did not look at cache"<<endl);
            }
          }
          else {
            *flawedNSSet=true;
            LOG(prefix<<qname<<": NS in cache for '"<<subdomain<<"', but needs glue ("<<nrr->getNS()<<") which we miss or is expired"<<endl);
          }
        }
      }

      if(!bestns.empty()) {
        GetBestNSAnswer answer;
        answer.qname=qname;
        answer.qtype=qtype.getCode();
        for(const auto& dr : bestns)
          answer.bestns.insert(make_pair(dr.d_name, getRR<NSRecordContent>(dr)->getNS()));

        if(beenthere.count(answer)) {
          brokeloop=true;
          LOG(prefix<<qname<<": We have NS in cache for '"<<subdomain<<"' but part of LOOP (already seen "<<answer.qname<<")! Trying less specific NS"<<endl);
          ;
          if(doLog())
            for( set<GetBestNSAnswer>::const_iterator j=beenthere.begin();j!=beenthere.end();++j) {
              bool neo = !(*j< answer || answer<*j);
              LOG(prefix<<qname<<": beenthere"<<(neo?"*":"")<<": "<<j->qname<<"|"<<DNSRecordContent::NumberToType(j->qtype)<<" ("<<(unsigned int)j->bestns.size()<<")"<<endl);
            }
          bestns.clear();
        }
        else {
          beenthere.insert(answer);
          LOG(prefix<<qname<<": We have NS in cache for '"<<subdomain<<"' (flawedNSSet="<<*flawedNSSet<<")"<<endl);
          return;
        }
      }
    }
    LOG(prefix<<qname<<": no valid/useful NS in cache for '"<<subdomain<<"'"<<endl);

    if(subdomain.isRoot() && !brokeloop) {
      // We lost the root NS records
      primeHints();
      LOG(prefix<<qname<<": reprimed the root"<<endl);
      /* let's prevent an infinite loop */
      if (!d_updatingRootNS) {
        getRootNS(d_now, d_asyncResolve);
      }
    }
  } while(subdomain.chopOff());
}

SyncRes::domainmap_t::const_iterator SyncRes::getBestAuthZone(DNSName* qname) const
{
  SyncRes::domainmap_t::const_iterator ret;
  do {
    ret=t_sstorage.domainmap->find(*qname);
    if(ret!=t_sstorage.domainmap->end())
      break;
  }while(qname->chopOff());
  return ret;
}

/** doesn't actually do the work, leaves that to getBestNSFromCache */
DNSName SyncRes::getBestNSNamesFromCache(const DNSName &qname, const QType& qtype, NsSet& nsset, bool* flawedNSSet, unsigned int depth, set<GetBestNSAnswer>&beenthere)
{
  DNSName subdomain(qname);
  DNSName authdomain(qname);

  domainmap_t::const_iterator iter=getBestAuthZone(&authdomain);
  if(iter!=t_sstorage.domainmap->end()) {
    if( iter->second.isAuth() )
      // this gets picked up in doResolveAt, the empty DNSName, combined with the
      // empty vector means 'we are auth for this zone'
      nsset.insert({DNSName(), {{}, false}});
    else {
      // Again, picked up in doResolveAt. An empty DNSName, combined with a
      // non-empty vector of ComboAddresses means 'this is a forwarded domain'
      // This is actually picked up in retrieveAddressesForNS called from doResolveAt.
      nsset.insert({DNSName(), {iter->second.d_servers, iter->second.shouldRecurse() }});
    }
    return authdomain;
  }

  vector<DNSRecord> bestns;
  getBestNSFromCache(subdomain, qtype, bestns, flawedNSSet, depth, beenthere);

  for(auto k=bestns.cbegin() ; k != bestns.cend(); ++k) {
    // The actual resolver code will not even look at the ComboAddress or bool
    nsset.insert({std::dynamic_pointer_cast<NSRecordContent>(k->d_content)->getNS(), {{}, false}}); 
    if(k==bestns.cbegin())
      subdomain=k->d_name;
  }
  return subdomain;
}

bool SyncRes::doCNAMECacheCheck(const DNSName &qname, const QType &qtype, vector<DNSRecord>& ret, unsigned int depth, int &res, vState& state)
{
  string prefix;
  if(doLog()) {
    prefix=d_prefix;
    prefix.append(depth, ' ');
  }

  if((depth>9 && d_outqueries>10 && d_throttledqueries>5) || depth > 15) {
    LOG(prefix<<qname<<": recursing (CNAME or other indirection) too deep, depth="<<depth<<endl);
    res=RCode::ServFail;
    return true;
  }

  LOG(prefix<<qname<<": Looking for CNAME cache hit of '"<<qname<<"|CNAME"<<"'"<<endl);
  vector<DNSRecord> cset;
  vector<std::shared_ptr<RRSIGRecordContent>> signatures;
  vector<std::shared_ptr<DNSRecord>> authorityRecs;
  if(t_RC->get(d_now.tv_sec, qname, QType(QType::CNAME), d_requireAuthData, &cset, d_requestor, d_doDNSSEC ? &signatures : nullptr, d_doDNSSEC ? &authorityRecs : nullptr, &d_wasVariable, &state) > 0) {

    for(auto j=cset.cbegin() ; j != cset.cend() ; ++j) {
      if(j->d_ttl>(unsigned int) d_now.tv_sec) {
        LOG(prefix<<qname<<": Found cache CNAME hit for '"<< qname << "|CNAME" <<"' to '"<<j->d_content->getZoneRepresentation()<<"', validation state is "<<vStates[state]<<endl);
        DNSRecord dr=*j;
        dr.d_ttl-=d_now.tv_sec;
        ret.push_back(dr);

        for(const auto& signature : signatures) {
          DNSRecord sigdr;
          sigdr.d_type=QType::RRSIG;
          sigdr.d_name=qname;
          sigdr.d_ttl=j->d_ttl - d_now.tv_sec;
          sigdr.d_content=signature;
          sigdr.d_place=DNSResourceRecord::ANSWER;
          sigdr.d_class=QClass::IN;
          ret.push_back(sigdr);
        }

        for(const auto& rec : authorityRecs) {
          DNSRecord dr(*rec);
          dr.d_ttl=j->d_ttl - d_now.tv_sec;
          ret.push_back(dr);
        }

        if(qtype != QType::CNAME) { // perhaps they really wanted a CNAME!
          set<GetBestNSAnswer>beenthere;

          vState cnameState = Indeterminate;
          res=doResolve(std::dynamic_pointer_cast<CNAMERecordContent>(j->d_content)->getTarget(), qtype, ret, depth+1, beenthere, cnameState);
          LOG("Updating validation state for response to "<<qname<<" from "<<vStates[state]<<" with the state from the CNAME quest: "<<vStates[cnameState]<<endl);
          updateValidationState(state, cnameState);
        }
        else
          res=0;

        return true;
      }
    }
  }
  LOG(prefix<<qname<<": No CNAME cache hit of '"<< qname << "|CNAME" <<"' found"<<endl);
  return false;
}

/*!
 * Convience function to push the records from records into ret with a new TTL
 *
 * \param records DNSRecords that need to go into ret
 * \param ttl     The new TTL for these records
 * \param ret     The vector of DNSRecords that should contian the records with the modified TTL
 */
static void addTTLModifiedRecords(const vector<DNSRecord>& records, const uint32_t ttl, vector<DNSRecord>& ret) {
  for (const auto& rec : records) {
    DNSRecord r(rec);
    r.d_ttl = ttl;
    ret.push_back(r);
  }
}


bool SyncRes::doCacheCheck(const DNSName &qname, const QType &qtype, vector<DNSRecord>&ret, unsigned int depth, int &res, vState& state)
{
  bool giveNegative=false;

  string prefix;
  if(doLog()) {
    prefix=d_prefix;
    prefix.append(depth, ' ');
  }

  // sqname and sqtype are used contain 'higher' names if we have them (e.g. powerdns.com|SOA when we find a negative entry for doesnotexists.powerdns.com|A)
  DNSName sqname(qname);
  QType sqt(qtype);
  uint32_t sttl=0;
  //  cout<<"Lookup for '"<<qname<<"|"<<qtype.getName()<<"' -> "<<getLastLabel(qname)<<endl;

  DNSName authname(qname);
  vState cachedState;
  bool wasForwardedOrAuth = false;
  bool wasAuth = false;
  domainmap_t::const_iterator iter=getBestAuthZone(&authname);
  if(iter != t_sstorage.domainmap->end()) {
    wasForwardedOrAuth = true;
    const vector<ComboAddress>& servers = iter->second.d_servers;
    if(servers.empty()) {
      wasAuth = true;
    }
  }
  NegCache::NegCacheEntry ne;

  if(s_rootNXTrust &&
     t_sstorage.negcache.getRootNXTrust(qname, d_now, ne) &&
      ne.d_auth.isRoot() &&
      !(wasForwardedOrAuth && !authname.isRoot())) { // when forwarding, the root may only neg-cache if it was forwarded to.
    sttl = ne.d_ttd - d_now.tv_sec;
    LOG(prefix<<qname<<": Entire name '"<<qname<<"', is negatively cached via '"<<ne.d_auth<<"' & '"<<ne.d_name<<"' for another "<<sttl<<" seconds"<<endl);
    res = RCode::NXDomain;
    giveNegative = true;
    cachedState = ne.d_validationState;
  }
  else if (t_sstorage.negcache.get(qname, qtype, d_now, ne) &&
           !(wasForwardedOrAuth && ne.d_auth != authname)) { // Only the authname nameserver can neg cache entries
    res = 0;
    sttl = ne.d_ttd - d_now.tv_sec;
    giveNegative = true;
    cachedState = ne.d_validationState;
    if(ne.d_qtype.getCode()) {
      LOG(prefix<<qname<<": "<<qtype.getName()<<" is negatively cached via '"<<ne.d_auth<<"' for another "<<sttl<<" seconds"<<endl);
      res = RCode::NoError;
    }
    else {
      LOG(prefix<<qname<<": Entire name '"<<qname<<"', is negatively cached via '"<<ne.d_auth<<"' for another "<<sttl<<" seconds"<<endl);
      res = RCode::NXDomain;
    }
    if(d_doDNSSEC) {
      addTTLModifiedRecords(ne.DNSSECRecords.records, sttl, ret);
      addTTLModifiedRecords(ne.DNSSECRecords.signatures, sttl, ret);
    }
  }

  if (giveNegative) {
    // Transplant SOA to the returned packet
    addTTLModifiedRecords(ne.authoritySOA.records, sttl, ret);
    if(d_doDNSSEC)
      addTTLModifiedRecords(ne.authoritySOA.signatures, sttl, ret);

    LOG("Updating validation state with negative cache content for "<<qname<<" to "<<vStates[cachedState]<<endl);
    state = cachedState;
    return true;
  }

  vector<DNSRecord> cset;
  bool found=false, expired=false;
  vector<std::shared_ptr<RRSIGRecordContent>> signatures;
  vector<std::shared_ptr<DNSRecord>> authorityRecs;
  uint32_t ttl=0;
  if(t_RC->get(d_now.tv_sec, sqname, sqt, d_requireAuthData, &cset, d_requestor, d_doDNSSEC ? &signatures : nullptr, d_doDNSSEC ? &authorityRecs : nullptr, &d_wasVariable, &cachedState) > 0) {
    LOG(prefix<<sqname<<": Found cache hit for "<<sqt.getName()<<": ");
    for(auto j=cset.cbegin() ; j != cset.cend() ; ++j) {
      LOG(j->d_content->getZoneRepresentation());
      if(j->d_ttl>(unsigned int) d_now.tv_sec) {
        DNSRecord dr=*j;
        ttl = (dr.d_ttl-=d_now.tv_sec);
        ret.push_back(dr);
        LOG("[ttl="<<dr.d_ttl<<"] ");
        found=true;
      }
      else {
        LOG("[expired] ");
        expired=true;
      }
    }

    for(const auto& signature : signatures) {
      DNSRecord dr;
      dr.d_type=QType::RRSIG;
      dr.d_name=sqname;
      dr.d_ttl=ttl; 
      dr.d_content=signature;
      dr.d_place = DNSResourceRecord::ANSWER;
      dr.d_class=QClass::IN;
      ret.push_back(dr);
    }

    for(const auto& rec : authorityRecs) {
      DNSRecord dr(*rec);
      dr.d_ttl=ttl;
      ret.push_back(dr);
    }

    LOG(endl);
    if(found && !expired) {
      if (!giveNegative)
        res=0;
      d_wasOutOfBand = wasAuth;
      LOG("Updating validation state with cache content for "<<qname<<" to "<<vStates[cachedState]<<endl);
      state = cachedState;
      return true;
    }
    else
      LOG(prefix<<qname<<": cache had only stale entries"<<endl);
  }

  return false;
}

bool SyncRes::moreSpecificThan(const DNSName& a, const DNSName &b) const
{
  return (a.isPartOf(b) && a.countLabels() > b.countLabels());
}

struct speedOrder
{
  speedOrder(map<DNSName,double> &speeds) : d_speeds(speeds) {}
  bool operator()(const DNSName &a, const DNSName &b) const
  {
    return d_speeds[a] < d_speeds[b];
  }
  map<DNSName, double>& d_speeds;
};

inline vector<DNSName> SyncRes::shuffleInSpeedOrder(NsSet &tnameservers, const string &prefix)
{
  vector<DNSName> rnameservers;
  rnameservers.reserve(tnameservers.size());
  for(const auto& tns:tnameservers) {
    rnameservers.push_back(tns.first);
  }
  map<DNSName, double> speeds;

  for(const auto& val: rnameservers) {
    double speed;
    speed=t_sstorage.nsSpeeds[val].get(&d_now);
    speeds[val]=speed;
  }
  random_shuffle(rnameservers.begin(),rnameservers.end(), dns_random);
  speedOrder so(speeds);
  stable_sort(rnameservers.begin(),rnameservers.end(), so);

  if(doLog()) {
    LOG(prefix<<"Nameservers: ");
    for(vector<DNSName>::const_iterator i=rnameservers.begin();i!=rnameservers.end();++i) {
                        if(i!=rnameservers.begin()) {
        LOG(", ");
        if(!((i-rnameservers.begin())%3)) {
          LOG(endl<<prefix<<"             ");
        }
      }
      LOG((i->empty() ? string("<empty>") : i->toString())<<"(" << (boost::format("%0.2f") % (speeds[*i]/1000.0)).str() <<"ms)");
    }
    LOG(endl);
  }
  return rnameservers;
}

static bool magicAddrMatch(const QType& query, const QType& answer)
{
  if(query.getCode() != QType::ADDR)
    return false;
  return answer.getCode() == QType::A || answer.getCode() == QType::AAAA;
}

static const set<uint16_t> nsecTypes = {QType::NSEC, QType::NSEC3};

/* Fills the authoritySOA and DNSSECRecords fields from ne with those found in the records
 *
 * \param records The records to parse for the authority SOA and NSEC(3) records
 * \param ne      The NegCacheEntry to be filled out (will not be cleared, only appended to
 */
static void harvestNXRecords(const vector<DNSRecord>& records, NegCache::NegCacheEntry& ne) {
  for(const auto& rec : records) {
    if(rec.d_place != DNSResourceRecord::AUTHORITY)
      // RFC 4035 section 3.1.3. indicates that NSEC records MUST be placed in
      // the AUTHORITY section. Section 3.1.1 indicates that that RRSIGs for
      // records MUST be in the same section as the records they cover.
      // Hence, we ignore all records outside of the AUTHORITY section.
      continue;

    if(rec.d_type == QType::RRSIG) {
      auto rrsig = getRR<RRSIGRecordContent>(rec);
      if(rrsig) {
        if(rrsig->d_type == QType::SOA) {
          ne.authoritySOA.signatures.push_back(rec);
        }
        if(nsecTypes.count(rrsig->d_type)) {
          ne.DNSSECRecords.signatures.push_back(rec);
        }
      }
      continue;
    }
    if(rec.d_type == QType::SOA) {
      ne.authoritySOA.records.push_back(rec);
      continue;
    }
    if(nsecTypes.count(rec.d_type)) {
      ne.DNSSECRecords.records.push_back(rec);
      continue;
    }
  }
}

static cspmap_t harvestCSPFromNE(const NegCache::NegCacheEntry& ne)
{
  cspmap_t cspmap;
  for(const auto& rec : ne.DNSSECRecords.signatures) {
    if(rec.d_type == QType::RRSIG) {
      auto rrc = getRR<RRSIGRecordContent>(rec);
      if (rrc) {
        cspmap[{rec.d_name,rrc->d_type}].signatures.push_back(rrc);
      }
    }
  }
  for(const auto& rec : ne.DNSSECRecords.records) {
    cspmap[{rec.d_name, rec.d_type}].records.push_back(rec.d_content);
  }
  return cspmap;
}

// TODO remove after processRecords is fixed!
// Adds the RRSIG for the SOA and the NSEC(3) + RRSIGs to ret
static void addNXNSECS(vector<DNSRecord>&ret, const vector<DNSRecord>& records)
{
  NegCache::NegCacheEntry ne;
  harvestNXRecords(records, ne);
  ret.insert(ret.end(), ne.authoritySOA.signatures.begin(), ne.authoritySOA.signatures.end());
  ret.insert(ret.end(), ne.DNSSECRecords.records.begin(), ne.DNSSECRecords.records.end());
  ret.insert(ret.end(), ne.DNSSECRecords.signatures.begin(), ne.DNSSECRecords.signatures.end());
}

bool SyncRes::nameserversBlockedByRPZ(const DNSFilterEngine& dfe, const NsSet& nameservers)
{
  if(d_wantsRPZ) {
    for (auto const &ns : nameservers) {
      d_appliedPolicy = dfe.getProcessingPolicy(ns.first, d_discardedPolicies);
      if (d_appliedPolicy.d_kind != DNSFilterEngine::PolicyKind::NoAction) { // client query needs an RPZ response
        LOG(", however nameserver "<<ns.first<<" was blocked by RPZ policy '"<<(d_appliedPolicy.d_name ? *d_appliedPolicy.d_name : "")<<"'"<<endl);
        return true;
      }

      // Traverse all IP addresses for this NS to see if they have an RPN NSIP policy
      for (auto const &address : ns.second.first) {
        d_appliedPolicy = dfe.getProcessingPolicy(address, d_discardedPolicies);
        if (d_appliedPolicy.d_kind != DNSFilterEngine::PolicyKind::NoAction) { // client query needs an RPZ response
          LOG(", however nameserver "<<ns.first<<" IP address "<<address.toString()<<" was blocked by RPZ policy '"<<(d_appliedPolicy.d_name ? *d_appliedPolicy.d_name : "")<<"'"<<endl);
          return true;
        }
      }
    }
  }
  return false;
}

bool SyncRes::nameserverIPBlockedByRPZ(const DNSFilterEngine& dfe, const ComboAddress& remoteIP)
{
  if (d_wantsRPZ) {
    d_appliedPolicy = dfe.getProcessingPolicy(remoteIP, d_discardedPolicies);
    if (d_appliedPolicy.d_kind != DNSFilterEngine::PolicyKind::NoAction) {
      LOG(" (blocked by RPZ policy '"+(d_appliedPolicy.d_name ? *d_appliedPolicy.d_name : "")+"')");
      return true;
    }
  }
  return false;
}

vector<ComboAddress> SyncRes::retrieveAddressesForNS(const std::string& prefix, const DNSName& qname, vector<DNSName >::const_iterator& tns, const unsigned int depth, set<GetBestNSAnswer>& beenthere, const vector<DNSName >& rnameservers, NsSet& nameservers, bool& sendRDQuery, bool& pierceDontQuery, bool& flawedNSSet)
{
  vector<ComboAddress> result;

  if(!tns->empty()) {
    LOG(prefix<<qname<<": Trying to resolve NS '"<<*tns<< "' ("<<1+tns-rnameservers.begin()<<"/"<<(unsigned int)rnameservers.size()<<")"<<endl);
    result = getAddrs(*tns, depth+2, beenthere);
    pierceDontQuery=false;
  }
  else {
    LOG(prefix<<qname<<": Domain has hardcoded nameserver");

    result = nameservers[*tns].first;
    if(result.size() > 1) {
      LOG("s");
    }
    LOG(endl);

    sendRDQuery = nameservers[*tns].second;
    pierceDontQuery=true;
  }
  return result;
}

bool SyncRes::throttledOrBlocked(const std::string& prefix, const ComboAddress& remoteIP, const DNSName& qname, const QType& qtype, bool pierceDontQuery)
{
  if(t_sstorage.throttle.shouldThrottle(d_now.tv_sec, boost::make_tuple(remoteIP, "", 0))) {
    LOG(prefix<<qname<<": server throttled "<<endl);
    s_throttledqueries++; d_throttledqueries++;
    return true;
  }
  else if(t_sstorage.throttle.shouldThrottle(d_now.tv_sec, boost::make_tuple(remoteIP, qname, qtype.getCode()))) {
    LOG(prefix<<qname<<": query throttled "<<remoteIP.toString()<<", "<<qname<<"; "<<qtype.getName()<<endl);
    s_throttledqueries++; d_throttledqueries++;
    return true;
  }
  else if(!pierceDontQuery && s_dontQuery && s_dontQuery->match(&remoteIP)) {
    LOG(prefix<<qname<<": not sending query to " << remoteIP.toString() << ", blocked by 'dont-query' setting" << endl);
    s_dontqueries++;
    return true;
  }
  return false;
}

bool SyncRes::validationEnabled() const
{
  return g_dnssecmode != DNSSECMode::Off && g_dnssecmode != DNSSECMode::ProcessNoValidate;
}

uint32_t SyncRes::computeLowestTTD(const std::vector<DNSRecord>& records, const std::vector<std::shared_ptr<RRSIGRecordContent> >& signatures, uint32_t signaturesTTL) const
{
  uint32_t lowestTTD = std::numeric_limits<uint32_t>::max();
  for(const auto& record : records)
    lowestTTD = min(lowestTTD, record.d_ttl);

  if (validationEnabled() && !signatures.empty()) {
    /* if we are validating, we don't want to cache records after their signatures
       expires. */
    /* records TTL are now TTD, let's add 'now' to the signatures lowest TTL */
    lowestTTD = min(lowestTTD, static_cast<uint32_t>(signaturesTTL + d_now.tv_sec));

    for(const auto& sig : signatures) {
      if (sig->d_siginception <= d_now.tv_sec && sig->d_sigexpire > d_now.tv_sec) {
        // we don't decerement d_sigexpire by 'now' because we actually want a TTD, not a TTL */
        lowestTTD = min(lowestTTD, static_cast<uint32_t>(sig->d_sigexpire));
      }
    }
  }

  return lowestTTD;
}

void SyncRes::updateValidationState(vState& state, const vState stateUpdate)
{
  LOG(d_prefix<<"validation state was "<<std::string(vStates[state])<<", state update is "<<std::string(vStates[stateUpdate])<<endl);

  if (stateUpdate == TA) {
    state = Secure;
  }
  else if (stateUpdate == NTA) {
    state = Insecure;
  }
  else if (stateUpdate == Bogus) {
    state = Bogus;
  }
  else if (state == Indeterminate) {
    state = stateUpdate;
  }
  else if (stateUpdate == Insecure) {
    if (state != Bogus) {
      state = Insecure;
    }
  }
  LOG(d_prefix<<" validation state is now "<<std::string(vStates[state])<<endl);
}

vState SyncRes::getTA(const DNSName& zone, dsmap_t& ds)
{
  auto luaLocal = g_luaconfs.getLocal();

  if (luaLocal->dsAnchors.empty()) {
    /* We have no TA, everything is insecure */
    return Insecure;
  }

  std::string reason;
  if (haveNegativeTrustAnchor(luaLocal->negAnchors, zone, reason)) {
    LOG("Got NTA for "<<zone<<endl);
    return NTA;
  }

  if (getTrustAnchor(luaLocal->dsAnchors, zone, ds)) {
    LOG("Got TA for "<<zone<<endl);
    return TA;
  }

  if (zone.isRoot()) {
    /* No TA for the root */
    return Insecure;
  }

  return Indeterminate;
}

static size_t countSupportedDS(const dsmap_t& dsmap)
{
  size_t count = 0;

  for (const auto& ds : dsmap) {
    if (isSupportedDS(ds)) {
      count++;
    }
  }

  return count;
}

vState SyncRes::getDSRecords(const DNSName& zone, dsmap_t& ds, bool taOnly, unsigned int depth)
{
  vState result = getTA(zone, ds);

  if (result != Indeterminate || taOnly) {
    if ((result == Secure || result == TA) && countSupportedDS(ds) == 0) {
      ds.clear();
      result = Insecure;
    }

    return result;
  }

  bool oldSkipCNAME = d_skipCNAMECheck;
  bool oldRequireAuthData = d_requireAuthData;
  d_skipCNAMECheck = true;
  d_requireAuthData = false;

  std::set<GetBestNSAnswer> beenthere;
  std::vector<DNSRecord> dsrecords;

  vState state = Indeterminate;
  int rcode = doResolve(zone, QType(QType::DS), dsrecords, depth + 1, beenthere, state);
  d_skipCNAMECheck = oldSkipCNAME;
  d_requireAuthData = oldRequireAuthData;

  if (rcode == RCode::NoError) {
    if (state == Secure) {
      for (const auto& record : dsrecords) {
        if (record.d_type == QType::DS) {
          const auto dscontent = getRR<DSRecordContent>(record);
          if (dscontent && isSupportedDS(*dscontent)) {
            ds.insert(*dscontent);
          }
        }
      }

      if (ds.empty()) {
        return Insecure;
      }
    }

    return state;
  }

  LOG("Returning Bogus state from "<<__func__<<"("<<zone<<")"<<endl);
  return Bogus;
}

vState SyncRes::getValidationStatus(const SyncRes::zonesStates_t& cuts, const DNSName& subdomain)
{
  vState result = Indeterminate;

  if (!validationEnabled()) {
    return result;
  }
  DNSName name(subdomain);
  do {
    const auto& it = cuts.find(name);
    if (it != cuts.cend()) {
      return it->second;
    }
  }
  while (name.chopOff());

  return result;
}

#if 0
vState SyncRes::getValidationStatus(const DNSName& subdomain, unsigned int depth)
{
  if (!validationEnabled()) {
    return Indeterminate;
  }

  dsmap_t ds;
  vState result = getTA(subdomain, ds);
  if (result != Indeterminate) {
    if (result == TA) {
      result = Secure;
    }
    else if (result == NTA) {
      result = Insecure;
    }

    if (result == Secure && countSupportedDS(ds) == 0) {
      ds.clear();
      result = Insecure;
    }

    return result;
  }

  vector<DNSRecord> cset;
  if(t_RC->get(d_now.tv_sec, subdomain, QType(QType::DS), false, &cset, d_requestor, nullptr, nullptr, nullptr, &result) > 0) {
    if (result != Indeterminate) {
      return result;
    }
  }

  /* we are out of luck */
  DNSName higher(subdomain);
  if (!higher.chopOff()) {
    /* No (N)TA for ".", something is very wrong */
    return Bogus;
  }

  result = getValidationStatus(higher, depth);

  if (result != Secure) {
    /* we know we don't have any (N)TA, so we are done */
    return result;
  }

  /* get subdomain DS */
  result = getDSRecords(subdomain, ds, false, depth);

  if (result == TA) {
    result = Secure;
  }
  else if (result != Secure) {
    if (result == NTA) {
      result = Insecure;
    }
    return result;
  }

  if (ds.empty()) {
    return Insecure;
  }

  return Secure;
}
#endif /* 0 */

SyncRes::zonesStates_t SyncRes::computeZoneCuts(const DNSName& begin, const DNSName& end, unsigned int depth)
{
  SyncRes::zonesStates_t cuts;
  dsmap_t ds;
  vState cutState = getDSRecords(end, ds, false, depth);
  if (cutState == TA) {
    cutState = Secure;
  }
  else if (cutState == NTA) {
    cutState = Insecure;
  }
  cuts[end] = cutState;

  cerr<<__func__<<", from "<<begin.toString()<<" to "<<end.toString()<<endl;

#warning using d_requireAuthData here seems wrong
  if (!validationEnabled() || !d_requireAuthData) {
    return cuts;
  }

  if(!begin.isPartOf(end)) {
    //throw PDNSException(end.toLogString() + " is not part of " + begin.toString());
    cerr<<end.toLogString()<<" is not part of "<<begin.toString()<<endl;
  }

  DNSName qname(end);
  std::vector<string> labelsToAdd = begin.makeRelative(end).getRawLabels();

  while(qname != begin) {
    bool foundCut = false;
    if (labelsToAdd.empty())
      break;

    qname.prependRawLabel(labelsToAdd.back());
    labelsToAdd.pop_back();
    cerr<<"- Looking for a cut at "<<qname<<endl;

    bool oldSkipCNAME = d_skipCNAMECheck;
    bool oldRequireAuthData = d_requireAuthData;
    d_skipCNAMECheck = true;
    d_requireAuthData = false;

    std::set<GetBestNSAnswer> beenthere;
    std::vector<DNSRecord> nsrecords;

    vState state = Indeterminate;
    int rcode = doResolve(qname, QType(QType::NS), nsrecords, depth + 1, beenthere, state);
    d_skipCNAMECheck = oldSkipCNAME;
    d_requireAuthData = oldRequireAuthData;

    if (rcode == RCode::NoError && !nsrecords.empty()) {
      for (const auto& record : nsrecords) {
        if(record.d_type != QType::NS || record.d_name != qname)
          continue;
        foundCut = true;
        break;
      }
      if (foundCut) {
        cerr<<"- Found cut at "<<qname<<endl;
        dsmap_t ds;
        cutState = getDSRecords(qname, ds, cutState == Insecure || cutState == Bogus, depth);
        cerr<<"New state is "<<vStates[cutState]<<endl;
        if (cutState == TA) {
          cutState = Secure;
        }
        else if (cutState == NTA) {
          cutState = Insecure;
        }
        cuts[qname] = cutState;
      }
    }
  }

  cerr<<"List of cuts from "<<begin<<" to "<<end<<endl;
  for (const auto& cut : cuts) {
    cerr<<" - "<<cut.first<<": "<<vStates[cut.second]<<endl;
  }

  return cuts;
}

void SyncRes::updateValidationStatusAfterReferral(const DNSName& qname, const DNSName& oldauth, const DNSName& newauth, vState& state, unsigned int depth)
{
  if (!validationEnabled()) {
    return;
  }

  dsmap_t ds;
  vState newState = getDSRecords(newauth, ds, state == Insecure || state == Bogus, depth);

  if (newState == Indeterminate) {
    /* no (N)TA */
    return;
  }

  if (newState == Secure) {
    if (ds.empty()) {
      updateValidationState(state, Insecure);
    }
    else {
      updateValidationState(state, Secure);
    }
  }
  else {
    updateValidationState(state, newState);
  }
}

vState SyncRes::validateDNSKeys(const DNSName& zone, const std::vector<DNSRecord>& dnskeys, const std::vector<std::shared_ptr<RRSIGRecordContent> >& signatures, unsigned int depth)
{
  dsmap_t ds;
  if (!signatures.empty()) {
    DNSName signer = getSigner(signatures);

    if (!signer.empty() && signer.isPartOf(zone)) {
      vState state = getDSRecords(signer, ds, false, depth);

      if (state == TA) {
        state = Secure;
      }
      if (state != Secure) {
        if (state == NTA) {
          state = Insecure;
        }
        return state;
      }
    }
  }

  skeyset_t tentativeKeys;
  std::vector<shared_ptr<DNSRecordContent> > toSign;

  for (const auto& dnskey : dnskeys) {
    if (dnskey.d_type == QType::DNSKEY) {
      auto content = getRR<DNSKEYRecordContent>(dnskey);
      if (content) {
        tentativeKeys.insert(content);
        toSign.push_back(content);
      }
    }
  }

  LOG("Trying to validate "<<std::to_string(tentativeKeys.size())<<" DNSKEYs with "<<std::to_string(ds.size())<<" DS"<<endl);
  skeyset_t validatedKeys;
  validateDNSKeysAgainstDS(d_now.tv_sec, zone, ds, tentativeKeys, toSign, signatures, validatedKeys);

  LOG("We now have "<<std::to_string(validatedKeys.size())<<" DNSKEYs"<<endl);

  if (validatedKeys.size() != tentativeKeys.size()) {
    LOG("Returning Bogus state from "<<__func__<<"("<<zone<<")"<<endl);
    return Bogus;
  }

  return Secure;
}

vState SyncRes::getDNSKeys(const DNSName& signer, skeyset_t& keys, unsigned int depth)
{
  std::vector<DNSRecord> records;
  std::set<GetBestNSAnswer> beenthere;
  LOG("Retrieving DNSKeys for "<<signer<<endl);

  vState state = Indeterminate;
  int rcode = doResolve(signer, QType(QType::DNSKEY), records, depth + 1, beenthere, state);

  if (rcode == RCode::NoError) {
    if (state == Secure) {
      for (const auto& key : records) {
        if (key.d_type == QType::DNSKEY) {
          auto content = getRR<DNSKEYRecordContent>(key);
          if (content) {
            keys.insert(content);
          }
        }
      }
    }
    LOG("Retrieved "<<keys.size()<<" DNSKeys for "<<signer<<", state is "<<vStates[state]<<endl);
    return state;
  }

  LOG("Returning Bogus state from "<<__func__<<"("<<signer<<")"<<endl);
  return Bogus;
}

vState SyncRes::validateRecordsWithSigs(unsigned int depth, const DNSName& name, const std::vector<DNSRecord>& records, const std::vector<std::shared_ptr<RRSIGRecordContent> >& signatures)
{
  skeyset_t keys;
  if (!signatures.empty()) {
    const DNSName signer = getSigner(signatures);
    if (!signer.empty() && name.isPartOf(signer)) {
      vState state = getDNSKeys(signer, keys, depth);
      if (state != Secure) {
        return state;
      }
    }
  } else {
    LOG("Bogus!"<<endl);
    return Bogus;
  }

  std::vector<std::shared_ptr<DNSRecordContent> > recordcontents;
  for (const auto& record : records) {
    recordcontents.push_back(record.d_content);
  }

  LOG("Going to validate "<<recordcontents.size()<< " record contents with "<<signatures.size()<<" sigs and "<<keys.size()<<" keys for "<<name<<endl);
  if (validateWithKeySet(d_now.tv_sec, name, recordcontents, signatures, keys, false)) {
    LOG("Secure!"<<endl);
    return Secure;
  }

  LOG("Bogus!"<<endl);
  return Bogus;
}

RCode::rcodes_ SyncRes::updateCacheFromRecords(unsigned int depth, LWResult& lwr, const DNSName& qname, const DNSName& auth, bool wasForwarded, const boost::optional<Netmask> ednsmask, vState& state, const SyncRes::zonesStates_t& cuts, bool& needWildcardProof)
{
  struct CacheEntry
  {
    vector<DNSRecord> records;
    vector<shared_ptr<RRSIGRecordContent>> signatures;
    uint32_t signaturesTTL{std::numeric_limits<uint32_t>::max()};
  };
  struct CacheKey
  {
    DNSName name;
    uint16_t type;
    DNSResourceRecord::Place place;
    bool operator<(const CacheKey& rhs) const {
      return tie(name, type) < tie(rhs.name, rhs.type);
    }
  };
  typedef map<CacheKey, CacheEntry> tcache_t;
  tcache_t tcache;

  string prefix;
  if(doLog()) {
    prefix=d_prefix;
    prefix.append(depth, ' ');
  }

  std::vector<std::shared_ptr<DNSRecord>> authorityRecs;
  for(const auto& rec : lwr.d_records) {
    if(needWildcardProof) {
      if (nsecTypes.count(rec.d_type)) {
        authorityRecs.push_back(std::make_shared<DNSRecord>(rec));
      }
      else if (rec.d_type == QType::RRSIG) {
        auto rrsig = getRR<RRSIGRecordContent>(rec);
        if (rrsig && nsecTypes.count(rrsig->d_type)) {
          authorityRecs.push_back(std::make_shared<DNSRecord>(rec));
        }
      }
    }
    if(rec.d_type == QType::RRSIG) {
      auto rrsig = getRR<RRSIGRecordContent>(rec);
      if (rrsig) {
        if (rec.d_name == qname && rrsig->d_labels < rec.d_name.countLabels()) {
          LOG(prefix<<qname<<": RRSIG indicates the name was expanded from a wildcard, we need a wildcard proof"<<endl);
          needWildcardProof = true;
        }

        //          cerr<<"Got an RRSIG for "<<DNSRecordContent::NumberToType(rrsig->d_type)<<" with name '"<<rec.d_name<<"'"<<endl;
        tcache[{rec.d_name, rrsig->d_type, rec.d_place}].signatures.push_back(rrsig);
        tcache[{rec.d_name, rrsig->d_type, rec.d_place}].signaturesTTL = std::min(tcache[{rec.d_name, rrsig->d_type, rec.d_place}].signaturesTTL, rec.d_ttl);
      }
    }
  }

  // reap all answers from this packet that are acceptable
  for(auto& rec : lwr.d_records) {
    if(rec.d_type == QType::OPT) {
      LOG(prefix<<qname<<": OPT answer '"<<rec.d_name<<"' from '"<<auth<<"' nameservers" <<endl);
      continue;
    }
    LOG(prefix<<qname<<": accept answer '"<<rec.d_name<<"|"<<DNSRecordContent::NumberToType(rec.d_type)<<"|"<<rec.d_content->getZoneRepresentation()<<"' from '"<<auth<<"' nameservers? "<<(int)rec.d_place<<" ");
    if(rec.d_type == QType::ANY) {
      LOG("NO! - we don't accept 'ANY' data"<<endl);
      continue;
    }

    if(rec.d_name.isPartOf(auth)) {
      if(rec.d_type == QType::RRSIG) {
        LOG("RRSIG - separate"<<endl);
      }
      else if(lwr.d_aabit && lwr.d_rcode==RCode::NoError && rec.d_place==DNSResourceRecord::ANSWER && ((rec.d_type != QType::DNSKEY && rec.d_type != QType::DS) || rec.d_name != auth) && s_delegationOnly.count(auth)) {
        LOG("NO! Is from delegation-only zone"<<endl);
        s_nodelegated++;
        return RCode::NXDomain;
      }
      else {
        bool haveLogged = false;
        if (!t_sstorage.domainmap->empty()) {
          // Check if we are authoritative for a zone in this answer
          DNSName tmp_qname(rec.d_name);
          auto auth_domain_iter=getBestAuthZone(&tmp_qname);
          if(auth_domain_iter!=t_sstorage.domainmap->end() &&
             auth.countLabels() <= auth_domain_iter->first.countLabels()) {
            if (auth_domain_iter->first != auth) {
              LOG("NO! - we are authoritative for the zone "<<auth_domain_iter->first<<endl);
              continue;
            } else {
              LOG("YES! - This answer was ");
              if (!wasForwarded) {
                LOG("retrieved from the local auth store.");
              } else {
                LOG("received from a server we forward to.");
              }
              haveLogged = true;
              LOG(endl);
            }
          }
        }
        if (!haveLogged) {
          LOG("YES!"<<endl);
        }

        rec.d_ttl=min(s_maxcachettl, rec.d_ttl);

        DNSRecord dr(rec);
        dr.d_ttl += d_now.tv_sec;
        dr.d_place=DNSResourceRecord::ANSWER;
        tcache[{rec.d_name,rec.d_type,rec.d_place}].records.push_back(dr);
      }
    }
    else
      LOG("NO!"<<endl);
  }

  // supplant
  for(tcache_t::iterator i = tcache.begin(); i != tcache.end(); ++i) {
    if((i->second.records.size() + i->second.signatures.size()) > 1) {  // need to group the ttl to be the minimum of the RRSET (RFC 2181, 5.2)
      uint32_t lowestTTD=computeLowestTTD(i->second.records, i->second.signatures, i->second.signaturesTTL);

      for(auto& record : i->second.records)
        record.d_ttl = lowestTTD; // boom
    }

//              cout<<"Have "<<i->second.records.size()<<" records and "<<i->second.signatures.size()<<" signatures for "<<i->first.name;
//              cout<<'|'<<DNSRecordContent::NumberToType(i->first.type)<<endl;
  }

  for(tcache_t::iterator i = tcache.begin(); i != tcache.end(); ++i) {

    if(i->second.records.empty()) // this happens when we did store signatures, but passed on the records themselves
      continue;

//    vState recordState = state;
    vState recordState = getValidationStatus(cuts, i->first.name);
    cerr<<"Got status "<<vStates[recordState]<<" for record "<<i->first.name<<endl;

    if (validationEnabled() && recordState == Secure) {
      if (lwr.d_aabit) {
        if (i->first.place != DNSResourceRecord::ADDITIONAL) {
          /* the additional entries can be insecure,
             like glue:
             "Glue address RRsets associated with delegations MUST NOT be signed"
          */
          if (i->first.type == QType::DNSKEY && i->first.place == DNSResourceRecord::ANSWER) {
            LOG("Validating DNSKEY for "<<i->first.name<<endl);
            recordState = validateDNSKeys(i->first.name, i->second.records, i->second.signatures, depth);
          }
          else {
            LOG("Validating non-additional record for "<<i->first.name<<endl);
            recordState = validateRecordsWithSigs(depth, i->first.name, i->second.records, i->second.signatures);
          }
        }
      }
      else {
        /* for non authoritative answer, we only care about the DS record (or lack of)  */
        if ((i->first.type == QType::DS || i->first.type == QType::NSEC || i->first.type == QType::NSEC3) && i->first.place == DNSResourceRecord::AUTHORITY) {
          LOG("Validating DS record for "<<i->first.name<<endl);
          recordState = validateRecordsWithSigs(depth, i->first.name, i->second.records, i->second.signatures);
        }
      }
      updateValidationState(state, recordState);
    }
    else {
      if (validationEnabled()) {
        LOG("Skipping validation because the current state is "<<vStates[state]<<endl);
      }
    }

    t_RC->replace(d_now.tv_sec, i->first.name, QType(i->first.type), i->second.records, i->second.signatures, authorityRecs, lwr.d_aabit, i->first.place == DNSResourceRecord::ANSWER ? ednsmask : boost::none, recordState);

    if(i->first.place == DNSResourceRecord::ANSWER && ednsmask)
      d_wasVariable=true;
  }

  return RCode::NoError;
}

void SyncRes::getDenialValidationState(NegCache::NegCacheEntry& ne, vState& state, const dState expectedState, bool allowOptOut)
{
  ne.d_validationState = state;

  if (state == Secure) {
    cspmap_t csp = harvestCSPFromNE(ne);
    dState res = getDenial(csp, ne.d_name, ne.d_qtype.getCode());
    if (res != expectedState) {
      if (res == OPTOUT && allowOptOut) {
        LOG("OPT-out denial found for "<<ne.d_name<<", retuning Insecure"<<endl);
        ne.d_validationState = Secure;
        updateValidationState(state, Insecure);
        return;
      }
      else if (res == INSECURE) {
        LOG("Insecure denial found for "<<ne.d_name<<", retuning Insecure"<<endl);
        ne.d_validationState = Insecure;
      }
      else {
        LOG("Invalid denial found for "<<ne.d_name<<", retuning Bogus"<<endl);
        ne.d_validationState = Bogus;
      }
      updateValidationState(state, ne.d_validationState);
    }
  }
}

bool SyncRes::processRecords(const std::string& prefix, const DNSName& qname, const QType& qtype, const DNSName& auth, LWResult& lwr, const bool sendRDQuery, vector<DNSRecord>& ret, set<DNSName>& nsset, DNSName& newtarget, DNSName& newauth, bool& realreferral, bool& negindic, vState& state, bool needWildcardProof)
{
  bool done = false;

  for(auto& rec : lwr.d_records) {
    if (rec.d_type!=QType::OPT && rec.d_class!=QClass::IN)
      continue;

    if(rec.d_place==DNSResourceRecord::AUTHORITY && rec.d_type==QType::SOA &&
       lwr.d_rcode==RCode::NXDomain && qname.isPartOf(rec.d_name) && rec.d_name.isPartOf(auth)) {
      LOG(prefix<<qname<<": got negative caching indication for name '"<<qname<<"' (accept="<<rec.d_name.isPartOf(auth)<<"), newtarget='"<<newtarget<<"'"<<endl);

      rec.d_ttl = min(rec.d_ttl, s_maxnegttl);
      if(newtarget.empty()) // only add a SOA if we're not going anywhere after this
        ret.push_back(rec);
      if(!wasVariable()) {
        NegCache::NegCacheEntry ne;

        ne.d_ttd = d_now.tv_sec + rec.d_ttl;
        ne.d_name = qname;
        ne.d_qtype = QType(0); // this encodes 'whole record'
        ne.d_auth = rec.d_name;
        harvestNXRecords(lwr.d_records, ne);
        getDenialValidationState(ne, state, NXDOMAIN, false);
        t_sstorage.negcache.add(ne);
        if(s_rootNXTrust && ne.d_auth.isRoot() && auth.isRoot()) {
          ne.d_name = ne.d_name.getLastLabel();
          t_sstorage.negcache.add(ne);
        }
      }

      negindic=true;
    }
    else if(rec.d_place==DNSResourceRecord::ANSWER && rec.d_type==QType::CNAME && (!(qtype==QType(QType::CNAME))) && rec.d_name == qname) {
      ret.push_back(rec);
      if (auto content = getRR<CNAMERecordContent>(rec)) {
        newtarget=content->getTarget();
      }
    }
    else if((rec.d_type==QType::RRSIG || rec.d_type==QType::NSEC || rec.d_type==QType::NSEC3) && rec.d_place==DNSResourceRecord::ANSWER) {
      if(rec.d_type != QType::RRSIG || rec.d_name == qname)
        ret.push_back(rec); // enjoy your DNSSEC
    }
    else if(needWildcardProof && (rec.d_type==QType::RRSIG || rec.d_type==QType::NSEC || rec.d_type==QType::NSEC3) && rec.d_place==DNSResourceRecord::AUTHORITY) {
      ret.push_back(rec); // enjoy your DNSSEC
    }
    // for ANY answers we *must* have an authoritative answer, unless we are forwarding recursively
    else if(rec.d_place==DNSResourceRecord::ANSWER && rec.d_name == qname &&
            (
              rec.d_type==qtype.getCode() || (lwr.d_aabit && (qtype==QType(QType::ANY) || magicAddrMatch(qtype, QType(rec.d_type)) ) ) || sendRDQuery
              )
      )
    {
      LOG(prefix<<qname<<": answer is in: resolved to '"<< rec.d_content->getZoneRepresentation()<<"|"<<DNSRecordContent::NumberToType(rec.d_type)<<"'"<<endl);

      done=true;
      ret.push_back(rec);
    }
    else if(rec.d_place==DNSResourceRecord::AUTHORITY && rec.d_type==QType::NS && qname.isPartOf(rec.d_name)) {
      if(moreSpecificThan(rec.d_name,auth)) {
        newauth=rec.d_name;
        LOG(prefix<<qname<<": got NS record '"<<rec.d_name<<"' -> '"<<rec.d_content->getZoneRepresentation()<<"'"<<endl);
        realreferral=true;
      }
      else {
        LOG(prefix<<qname<<": got upwards/level NS record '"<<rec.d_name<<"' -> '"<<rec.d_content->getZoneRepresentation()<<"', had '"<<auth<<"'"<<endl);
      }
      if (auto content = getRR<NSRecordContent>(rec)) {
        nsset.insert(content->getNS());
      }
    }
    else if(rec.d_place==DNSResourceRecord::AUTHORITY && rec.d_type==QType::DS && qname.isPartOf(rec.d_name)) {
      LOG(prefix<<qname<<": got DS record '"<<rec.d_name<<"' -> '"<<rec.d_content->getZoneRepresentation()<<"'"<<endl);
    }
    else if(realreferral && rec.d_place==DNSResourceRecord::AUTHORITY && (rec.d_type==QType::NSEC || rec.d_type==QType::NSEC3) && newauth.isPartOf(auth)) {
      /* we might have received a denial of the DS, let's check */
      if (state == Secure) {
        NegCache::NegCacheEntry ne;
        ne.d_auth = auth;
        ne.d_ttd = d_now.tv_sec + rec.d_ttl;
        ne.d_name = newauth;
        ne.d_qtype = QType::DS;
        harvestNXRecords(lwr.d_records, ne);
        cspmap_t csp = harvestCSPFromNE(ne);
        dState denialState = getDenial(csp, newauth, QType::DS);
        if (denialState == NXQTYPE || denialState == OPTOUT || denialState == INSECURE) {
          ne.d_validationState = Secure;
          rec.d_ttl = min(s_maxnegttl, rec.d_ttl);
          LOG(prefix<<qname<<": got negative indication of DS record for '"<<newauth<<"'"<<endl);
          updateValidationState(state, Insecure);
          if(!wasVariable()) {
            t_sstorage.negcache.add(ne);
          }
        }
      }
    }
    else if(!done && rec.d_place==DNSResourceRecord::AUTHORITY && rec.d_type==QType::SOA &&
            lwr.d_rcode==RCode::NoError && qname.isPartOf(rec.d_name)) {
      LOG(prefix<<qname<<": got negative caching indication for '"<< qname<<"|"<<qtype.getName()<<"'"<<endl);

      if(!newtarget.empty()) {
        LOG(prefix<<qname<<": Hang on! Got a redirect to '"<<newtarget<<"' already"<<endl);
      }
      else {
        rec.d_ttl = min(s_maxnegttl, rec.d_ttl);
        ret.push_back(rec);
        if(!wasVariable()) {
          NegCache::NegCacheEntry ne;
          ne.d_auth = rec.d_name;
          ne.d_ttd = d_now.tv_sec + rec.d_ttl;
          ne.d_name = qname;
          ne.d_qtype = qtype;
          harvestNXRecords(lwr.d_records, ne);
          getDenialValidationState(ne, state, NXQTYPE, qtype == QType::DS);
          if(qtype.getCode()) {  // prevents us from blacking out a whole domain
            t_sstorage.negcache.add(ne);
          }
        }
        negindic=true;
      }
    }
  }

  return done;
}

bool SyncRes::doResolveAtThisIP(const std::string& prefix, const DNSName& qname, const QType& qtype, LWResult& lwr, boost::optional<Netmask>& ednsmask, const DNSName& auth, bool const sendRDQuery, const DNSName& nsName, const ComboAddress& remoteIP, bool doTCP, bool* truncated)
{
  int resolveret;
  s_outqueries++;
  d_outqueries++;

  if(d_outqueries + d_throttledqueries > s_maxqperq) {
    throw ImmediateServFailException("more than "+std::to_string(s_maxqperq)+" (max-qperq) queries sent while resolving "+qname.toLogString());
  }

  if(s_maxtotusec && d_totUsec > s_maxtotusec) {
    throw ImmediateServFailException("Too much time waiting for "+qname.toLogString()+"|"+qtype.getName()+", timeouts: "+std::to_string(d_timeouts) +", throttles: "+std::to_string(d_throttledqueries) + ", queries: "+std::to_string(d_outqueries)+", "+std::to_string(d_totUsec/1000)+"msec");
  }

  if(doTCP) {
    LOG(prefix<<qname<<": using TCP with "<< remoteIP.toStringWithPort() <<endl);
    s_tcpoutqueries++;
    d_tcpoutqueries++;
  }

  if(d_pdl && d_pdl->preoutquery(remoteIP, d_requestor, qname, qtype, doTCP, lwr.d_records, resolveret)) {
    LOG(prefix<<qname<<": query handled by Lua"<<endl);
  }
  else {
    ednsmask=getEDNSSubnetMask(d_requestor, qname, remoteIP);
    if(ednsmask) {
      LOG(prefix<<qname<<": Adding EDNS Client Subnet Mask "<<ednsmask->toString()<<" to query"<<endl);
    }
    resolveret = asyncresolveWrapper(remoteIP, d_doDNSSEC, qname,  qtype.getCode(),
                                     doTCP, sendRDQuery, &d_now, ednsmask, &lwr);    // <- we go out on the wire!
    if(ednsmask) {
      LOG(prefix<<qname<<": Received EDNS Client Subnet Mask "<<ednsmask->toString()<<" on response"<<endl);
    }
  }

  /* preoutquery killed the query by setting dq.rcode to -3 */
  if(resolveret==-3) {
    throw ImmediateServFailException("Query killed by policy");
  }

  d_totUsec += lwr.d_usec;
  accountAuthLatency(lwr.d_usec, remoteIP.sin4.sin_family);

  if(resolveret != 1) {
    /* Error while resolving */
    if(resolveret == 0) {
      /* Time out */

      LOG(prefix<<qname<<": timeout resolving after "<<lwr.d_usec/1000.0<<"msec "<< (doTCP ? "over TCP" : "")<<endl);
      d_timeouts++;
      s_outgoingtimeouts++;

      if(remoteIP.sin4.sin_family == AF_INET)
        s_outgoing4timeouts++;
      else
        s_outgoing6timeouts++;
    }
    else if(resolveret == -2) {
      /* OS resource limit reached */
      LOG(prefix<<qname<<": hit a local resource limit resolving"<< (doTCP ? " over TCP" : "")<<", probable error: "<<stringerror()<<endl);
      g_stats.resourceLimits++;
    }
    else {
      /* -1 means server unreachable */
      s_unreachables++;
      d_unreachables++;
      LOG(prefix<<qname<<": error resolving from "<<remoteIP.toString()<< (doTCP ? " over TCP" : "") <<", possible error: "<<strerror(errno)<< endl);
    }

    if(resolveret != -2) { // don't account for resource limits, they are our own fault
      t_sstorage.nsSpeeds[nsName].submit(remoteIP, 1000000, &d_now); // 1 sec

      // code below makes sure we don't filter COM or the root
      if (s_serverdownmaxfails > 0 && (auth != g_rootdnsname) && t_sstorage.fails.incr(remoteIP) >= s_serverdownmaxfails) {
        LOG(prefix<<qname<<": Max fails reached resolving on "<< remoteIP.toString() <<". Going full throttle for "<< s_serverdownthrottletime <<" seconds" <<endl);
        // mark server as down
        t_sstorage.throttle.throttle(d_now.tv_sec, boost::make_tuple(remoteIP, "", 0), s_serverdownthrottletime, 10000);
      }
      else if (resolveret == -1) {
        // unreachable, 1 minute or 100 queries
        t_sstorage.throttle.throttle(d_now.tv_sec, boost::make_tuple(remoteIP, qname, qtype.getCode()), 60, 100);
      }
      else {
        // timeout
        t_sstorage.throttle.throttle(d_now.tv_sec, boost::make_tuple(remoteIP, qname, qtype.getCode()), 10, 5);
      }
    }

    return false;
  }

  /* we got an answer */
  if(lwr.d_rcode==RCode::ServFail || lwr.d_rcode==RCode::Refused) {
    LOG(prefix<<qname<<": "<<nsName<<" ("<<remoteIP.toString()<<") returned a "<< (lwr.d_rcode==RCode::ServFail ? "ServFail" : "Refused") << ", trying sibling IP or NS"<<endl);
    t_sstorage.throttle.throttle(d_now.tv_sec, boost::make_tuple(remoteIP, qname, qtype.getCode()), 60, 3);
    return false;
  }

  /* this server sent a valid answer, mark it backup up if it was down */
  if(s_serverdownmaxfails > 0) {
    t_sstorage.fails.clear(remoteIP);
  }

  if(lwr.d_tcbit) {
    *truncated = true;

    if (doTCP) {
      LOG(prefix<<qname<<": truncated bit set, over TCP?"<<endl);
      /* let's treat that as a ServFail answer from this server */
      t_sstorage.throttle.throttle(d_now.tv_sec, boost::make_tuple(remoteIP, qname, qtype.getCode()), 60, 3);
      return false;
    }

    return true;
  }

  return true;
}

bool SyncRes::processAnswer(unsigned int depth, LWResult& lwr, const DNSName& qname, const QType& qtype, DNSName& auth, bool wasForwarded, const boost::optional<Netmask> ednsmask, bool sendRDQuery, NsSet &nameservers, std::vector<DNSRecord>& ret, const DNSFilterEngine& dfe, bool* gotNewServers, int* rcode, vState& state, const SyncRes::zonesStates_t& cuts)
{
  string prefix;
  if(doLog()) {
    prefix=d_prefix;
    prefix.append(depth, ' ');
  }

  if(s_minimumTTL) {
    for(auto& rec : lwr.d_records) {
      rec.d_ttl = max(rec.d_ttl, s_minimumTTL);
    }
  }

  bool needWildcardProof = false;
  *rcode = updateCacheFromRecords(depth, lwr, qname, auth, wasForwarded, ednsmask, state, cuts, needWildcardProof);
  if (*rcode != RCode::NoError) {
    return true;
  }

  LOG(prefix<<qname<<": determining status after receiving this packet"<<endl);

  set<DNSName> nsset;
  bool realreferral=false, negindic=false;
  DNSName newauth;
  DNSName newtarget;

  bool done = processRecords(prefix, qname, qtype, auth, lwr, sendRDQuery, ret, nsset, newtarget, newauth, realreferral, negindic, state, needWildcardProof);

  if(done){
    LOG(prefix<<qname<<": status=got results, this level of recursion done"<<endl);
    *rcode = RCode::NoError;
    return true;
  }

  if(!newtarget.empty()) {
    if(newtarget == qname) {
      LOG(prefix<<qname<<": status=got a CNAME referral to self, returning SERVFAIL"<<endl);
      *rcode = RCode::ServFail;
      return true;
    }

    if(depth > 10) {
      LOG(prefix<<qname<<": status=got a CNAME referral, but recursing too deep, returning SERVFAIL"<<endl);
      *rcode = RCode::ServFail;
      return true;
    }

    LOG(prefix<<qname<<": status=got a CNAME referral, starting over with "<<newtarget<<endl);

    set<GetBestNSAnswer> beenthere2;
    vState cnameState = Indeterminate;
    *rcode = doResolve(newtarget, qtype, ret, depth + 1, beenthere2, cnameState);
    LOG("Updating validation state for response to "<<qname<<" from "<<vStates[state]<<" with the state from the CNAME quest: "<<vStates[cnameState]<<endl);
    updateValidationState(state, cnameState);

    return true;
  }

  if(lwr.d_rcode == RCode::NXDomain) {
    LOG(prefix<<qname<<": status=NXDOMAIN, we are done "<<(negindic ? "(have negative SOA)" : "")<<endl);

    if(d_doDNSSEC)
      addNXNSECS(ret, lwr.d_records);

    *rcode = RCode::NXDomain;
    return true;
  }

  if(nsset.empty() && !lwr.d_rcode && (negindic || lwr.d_aabit || sendRDQuery)) {
    LOG(prefix<<qname<<": status=noerror, other types may exist, but we are done "<<(negindic ? "(have negative SOA) " : "")<<(lwr.d_aabit ? "(have aa bit) " : "")<<endl);

    if(d_doDNSSEC)
      addNXNSECS(ret, lwr.d_records);

    *rcode = RCode::NoError;
    return true;
  }

  if(realreferral) {
    LOG(prefix<<qname<<": status=did not resolve, got "<<(unsigned int)nsset.size()<<" NS, ");

    nameservers.clear();
    for (auto const &nameserver : nsset) {
      if (d_wantsRPZ) {
        d_appliedPolicy = dfe.getProcessingPolicy(nameserver, d_discardedPolicies);
        if (d_appliedPolicy.d_kind != DNSFilterEngine::PolicyKind::NoAction) { // client query needs an RPZ response
          LOG("however "<<nameserver<<" was blocked by RPZ policy '"<<(d_appliedPolicy.d_name ? *d_appliedPolicy.d_name : "")<<"'"<<endl);
          *rcode = -2;
          return true;
        }
      }
      nameservers.insert({nameserver, {{}, false}});
    }
    LOG("looping to them"<<endl);
    *gotNewServers = true;
    //updateValidationStatusAfterReferral(qname, auth, newauth, state, depth);
    auth=newauth;

    return false;
  }

  return false;
}

/** returns:
 *  -1 in case of no results
 *  -2 when a FilterEngine Policy was hit
 *  rcode otherwise
 */
int SyncRes::doResolveAt(NsSet &nameservers, DNSName auth, bool flawedNSSet, const DNSName &qname, const QType &qtype,
                         vector<DNSRecord>&ret,
                         unsigned int depth, set<GetBestNSAnswer>&beenthere, vState& state, const SyncRes::zonesStates_t& cuts)
{
  auto luaconfsLocal = g_luaconfs.getLocal();
  string prefix;
  if(doLog()) {
    prefix=d_prefix;
    prefix.append(depth, ' ');
  }

  LOG(prefix<<qname<<": Cache consultations done, have "<<(unsigned int)nameservers.size()<<" NS to contact");

  if (nameserversBlockedByRPZ(luaconfsLocal->dfe, nameservers)) {
    return -2;
  }

  LOG(endl);

  for(;;) { // we may get more specific nameservers
    vector<DNSName > rnameservers = shuffleInSpeedOrder(nameservers, doLog() ? (prefix+qname.toString()+": ") : string() );

    for(auto tns=rnameservers.cbegin();;++tns) {
      if(tns==rnameservers.cend()) {
        LOG(prefix<<qname<<": Failed to resolve via any of the "<<(unsigned int)rnameservers.size()<<" offered NS at level '"<<auth<<"'"<<endl);
        if(!auth.isRoot() && flawedNSSet) {
          LOG(prefix<<qname<<": Ageing nameservers for level '"<<auth<<"', next query might succeed"<<endl);

          if(t_RC->doAgeCache(d_now.tv_sec, auth, QType::NS, 10))
            g_stats.nsSetInvalidations++;
        }
        return -1;
      }

      // this line needs to identify the 'self-resolving' behaviour, but we get it wrong now
      if(qname == *tns && qtype.getCode()==QType::A && rnameservers.size() > (size_t)(1+1*s_doIPv6)) {
        LOG(prefix<<qname<<": Not using NS to resolve itself! ("<<(1+tns-rnameservers.cbegin())<<"/"<<rnameservers.size()<<")"<<endl);
        continue;
      }

      typedef vector<ComboAddress> remoteIPs_t;
      remoteIPs_t remoteIPs;
      remoteIPs_t::const_iterator remoteIP;
      bool pierceDontQuery=false;
      bool sendRDQuery=false;
      boost::optional<Netmask> ednsmask;
      LWResult lwr;
      const bool wasForwarded = tns->empty() && (!nameservers[*tns].first.empty());
      int rcode = RCode::NoError;
      bool gotNewServers = false;

      if(tns->empty() && !wasForwarded) {
        LOG(prefix<<qname<<": Domain is out-of-band"<<endl);
        state = Insecure;
        d_wasOutOfBand = doOOBResolve(qname, qtype, lwr.d_records, depth, lwr.d_rcode);
        lwr.d_tcbit=false;
        lwr.d_aabit=true;

        /* we have received an answer, are we done ? */
        bool done = processAnswer(depth, lwr, qname, qtype, auth, false, ednsmask, sendRDQuery, nameservers, ret, luaconfsLocal->dfe, &gotNewServers, &rcode, state, cuts);
        if (done) {
          return rcode;
        }
        if (gotNewServers) {
          break;
        }
      }
      else {
        /* if tns is empty, retrieveAddressesForNS() knows we have hardcoded servers (i.e. "forwards") */
        remoteIPs = retrieveAddressesForNS(prefix, qname, tns, depth, beenthere, rnameservers, nameservers, sendRDQuery, pierceDontQuery, flawedNSSet);

        if(remoteIPs.empty()) {
          LOG(prefix<<qname<<": Failed to get IP for NS "<<*tns<<", trying next if available"<<endl);
          flawedNSSet=true;
          continue;
        }
        else {
          bool hitPolicy{false};
          LOG(prefix<<qname<<": Resolved '"<<auth<<"' NS "<<*tns<<" to: ");
          for(remoteIP = remoteIPs.cbegin(); remoteIP != remoteIPs.cend(); ++remoteIP) {
            if(remoteIP != remoteIPs.cbegin()) {
              LOG(", ");
            }
            LOG(remoteIP->toString());
            if(nameserverIPBlockedByRPZ(luaconfsLocal->dfe, *remoteIP)) {
              hitPolicy = true;
            }
          }
          LOG(endl);
          if (hitPolicy) //implies d_wantsRPZ
            return -2;
        }

        for(remoteIP = remoteIPs.cbegin(); remoteIP != remoteIPs.cend(); ++remoteIP) {
          LOG(prefix<<qname<<": Trying IP "<< remoteIP->toStringWithPort() <<", asking '"<<qname<<"|"<<qtype.getName()<<"'"<<endl);

          if (throttledOrBlocked(prefix, *remoteIP, qname, qtype, pierceDontQuery)) {
            continue;
          }

          bool truncated = false;
          bool gotAnswer = doResolveAtThisIP(prefix, qname, qtype, lwr, ednsmask, auth, sendRDQuery,
                                             *tns, *remoteIP, false, &truncated);
          if (gotAnswer && truncated ) {
            /* retry, over TCP this time */
            gotAnswer = doResolveAtThisIP(prefix, qname, qtype, lwr, ednsmask, auth, sendRDQuery,
                                          *tns, *remoteIP, true, &truncated);
          }

          if (!gotAnswer) {
            continue;
          }

          LOG(prefix<<qname<<": Got "<<(unsigned int)lwr.d_records.size()<<" answers from "<<*tns<<" ("<< remoteIP->toString() <<"), rcode="<<lwr.d_rcode<<" ("<<RCode::to_s(lwr.d_rcode)<<"), aa="<<lwr.d_aabit<<", in "<<lwr.d_usec/1000<<"ms"<<endl);

          /*  // for you IPv6 fanatics :-)
              if(remoteIP->sin4.sin_family==AF_INET6)
              lwr.d_usec/=3;
          */
          //        cout<<"msec: "<<lwr.d_usec/1000.0<<", "<<g_avgLatency/1000.0<<'\n';

          t_sstorage.nsSpeeds[*tns].submit(*remoteIP, lwr.d_usec, &d_now);

          /* we have received an answer, are we done ? */
          bool done = processAnswer(depth, lwr, qname, qtype, auth, wasForwarded, ednsmask, sendRDQuery, nameservers, ret, luaconfsLocal->dfe, &gotNewServers, &rcode, state, cuts);
          if (done) {
            return rcode;
          }
          if (gotNewServers) {
            break;
          }
          /* was lame */
          t_sstorage.throttle.throttle(d_now.tv_sec, boost::make_tuple(*remoteIP, qname, qtype.getCode()), 60, 100);
        }

        if (gotNewServers) {
          break;
        }

        if(remoteIP == remoteIPs.cend())  // we tried all IP addresses, none worked
          continue;

      }
    }
  }
  return -1;
}

boost::optional<Netmask> SyncRes::getEDNSSubnetMask(const ComboAddress& local, const DNSName&dn, const ComboAddress& rem)
{
  boost::optional<Netmask> result;
  ComboAddress trunc;
  uint8_t bits;
  if(d_incomingECSFound) {
    if (d_incomingECS->source.getBits() == 0) {
      /* RFC7871 says we MUST NOT send any ECS if the source scope is 0 */
      return result;
    }
    trunc = d_incomingECS->source.getMaskedNetwork();
    bits = d_incomingECS->source.getBits();
  }
  else if(!local.isIPv4() || local.sin4.sin_addr.s_addr) { // detect unset 'requestor'
    trunc = local;
    bits = local.isIPv4() ? 32 : 128;
  }
  else {
    /* nothing usable */
    return result;
  }

  if(s_ednsdomains.check(dn) || s_ednssubnets.match(rem)) {
    bits = std::min(bits, (trunc.isIPv4() ? s_ecsipv4limit : s_ecsipv6limit));
    trunc.truncate(bits);
    return boost::optional<Netmask>(Netmask(trunc, bits));
  }

  return result;
}

void SyncRes::parseEDNSSubnetWhitelist(const std::string& wlist)
{
  vector<string> parts;
  stringtok(parts, wlist, ",; ");
  for(const auto& a : parts) {
    try {
      s_ednssubnets.addMask(Netmask(a));
    }
    catch(...) {
      s_ednsdomains.add(DNSName(a));
    }
  }
}

// used by PowerDNSLua - note that this neglects to add the packet count & statistics back to pdns_ercursor.cc
int directResolve(const DNSName& qname, const QType& qtype, int qclass, vector<DNSRecord>& ret)
{
  struct timeval now;
  gettimeofday(&now, 0);

  SyncRes sr(now);
  int res = sr.beginResolve(qname, QType(qtype), qclass, ret); 
  
  return res;
}

int SyncRes::getRootNS(struct timeval now, asyncresolve_t asyncCallback) {
  SyncRes sr(now);
  sr.setDoEDNS0(true);
  sr.setUpdatingRootNS();
  sr.setDoDNSSEC(g_dnssecmode != DNSSECMode::Off);
  sr.setAsyncCallback(asyncCallback);

  vector<DNSRecord> ret;
  int res=-1;
  try {
    res=sr.beginResolve(g_rootdnsname, QType(QType::NS), 1, ret);
    if (g_dnssecmode != DNSSECMode::Off && g_dnssecmode != DNSSECMode::ProcessNoValidate) {
      auto state = sr.getValidationState();
      if (state == Bogus)
        throw PDNSException("Got Bogus validation result for .|NS");
    }
    return res;
  }
  catch(const PDNSException& e) {
    L<<Logger::Error<<"Failed to update . records, got an exception: "<<e.reason<<endl;
  }
  catch(const ImmediateServFailException& e) {
    L<<Logger::Error<<"Failed to update . records, got an exception: "<<e.reason<<endl;
  }
  catch(const std::exception& e) {
    L<<Logger::Error<<"Failed to update . records, got an exception: "<<e.what()<<endl;
  }
  catch(...) {
    L<<Logger::Error<<"Failed to update . records, got an exception"<<endl;
  }

  if(!res) {
    L<<Logger::Notice<<"Refreshed . records"<<endl;
  }
  else
    L<<Logger::Error<<"Failed to update . records, RCODE="<<res<<endl;

  return res;
}