root/trunk/pdns/pdns/packethandler.cc @ 167

/*
    PowerDNS Versatile Database Driven Nameserver
    Copyright (C) 2002  PowerDNS.COM BV

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
#include "utility.hh"
#include <string>
#include <sys/types.h>

#include "dns.hh"
#include "dnsbackend.hh"
#include "ueberbackend.hh"
#include "dnspacket.hh"
#include "nameserver.hh"
#include "distributor.hh"
#include "logger.hh"
#include "arguments.hh"
#include "packethandler.hh"
#include "statbag.hh"
#include "resolver.hh"
#include "communicator.hh"
#include "dnsproxy.hh"

extern StatBag S;
extern PacketCache PC;  
extern CommunicatorClass Communicator;
extern DNSProxy *DP;

int PacketHandler::s_count;
extern string s_programname;

PacketHandler::PacketHandler():B(s_programname)
{
  s_count++;
  d_doFancyRecords = (arg()["fancy-records"]!="no");
  d_doWildcards = (arg()["wildcards"]!="no");
  d_doCNAME = (arg()["skip-cname"]=="no");
  d_doRecursion= arg().mustDo("recursor");
  d_logDNSDetails= arg().mustDo("log-dns-details");
  d_doIPv6AdditionalProcessing = arg().mustDo("do-ipv6-additional-processing");
}

DNSBackend *PacketHandler::getBackend()
{
  return &B;
}

PacketHandler::~PacketHandler()
{
  --s_count;
  DLOG(L<<Logger::Error<<"PacketHandler destructor called - "<<s_count<<" left"<<endl);
}


int PacketHandler::findMboxFW(DNSPacket *p, DNSPacket *r, string &target)
{
  DNSResourceRecord rr;
  bool wedoforward=false;

  SOAData sd;
  int zoneId;
  if(!getAuth(p, &sd, target, &zoneId))
    return false;

  B.lookup("MBOXFW",string("%@")+target,p, zoneId);
      
  while(B.get(rr))
    wedoforward=true;

  if(wedoforward) {
    rr.content=arg()["smtpredirector"];
    rr.priority=25;
    rr.ttl=7200;
    rr.qtype=QType::MX;
    rr.qname=target;
    
    r->addRecord(rr);
  }

  return wedoforward;
}

int PacketHandler::findUrl(DNSPacket *p, DNSPacket *r, string &target)
{
  DNSResourceRecord rr;

  bool found=false;
      
  B.lookup("URL",target,p); // search for a URL before we search for an A
        
  while(B.get(rr)) {
    found=true;
    DLOG(L << "Found a URL!" << endl);
    rr.content=arg()["urlredirector"];
    rr.qtype=QType::A; 
    rr.qname=target;
          
    r->addRecord(rr);
  }  

  if(found)
    return 1;
      
  // now try CURL
  
  B.lookup("CURL",target,p); // search for a URL before we search for an A
      
  while(B.get(rr)) {
    found=true;
    DLOG(L << "Found a CURL!" << endl);
    rr.content=arg()["urlredirector"];
    rr.qtype=1; // A
    rr.qname=target;
    rr.ttl=300;
    r->addRecord(rr);
  }  

  if(found)
    return found;
  return 0;
}

/** Returns 0 if nothing was found, -1 if an error occured or 1 if the search
    was satisfied */
int PacketHandler::doFancyRecords(DNSPacket *p, DNSPacket *r, string &target)
{
  DNSResourceRecord rr;

  if(p->qtype.getCode()==QType::MX)  // check if this domain has smtp service from us
    return findMboxFW(p,r,target);
  
  if(p->qtype.getCode()==QType::A)   // search for a URL record for an A
    return findUrl(p,r,target);

  return 0;
}

int PacketHandler::doDNSCheckRequest(DNSPacket *p, DNSPacket *r, string &target)
{
  int result = 0;
  DNSResourceRecord rr;

  if (p->qclass == 3 && p->qtype.getName() == "HINFO") {
    rr.content = "PowerDNS $Id: packethandler.cc,v 1.14 2003/04/05 19:31:52 ahu Exp $";
    rr.ttl = 5;
    rr.qname=target;
    rr.qtype=13; // hinfo
    r->addRecord(rr);
    result = 1;
  }
  
  return result;
}

/** This catches version requests. Returns 1 if it was handled, 0 if it wasn't */
int PacketHandler::doVersionRequest(DNSPacket *p, DNSPacket *r, string &target)
{
  DNSResourceRecord rr;
  if(p->qtype.getCode()==QType::TXT && target=="version.bind") {// TXT
    rr.content="Served by POWERDNS "VERSION" $Id: packethandler.cc,v 1.14 2003/04/05 19:31:52 ahu Exp $";
    rr.ttl=5;
    rr.qname=target;
    rr.qtype=QType::TXT; // TXT
    r->addRecord(rr);
    
    return 1;
  }
  return 0;
}

/** Determines if we are authoritative for a zone, and at what level */
bool PacketHandler::getTLDAuth(DNSPacket *p, SOAData *sd, const string &target, int *zoneId)
{
  static string theSOA="."+arg()["only-soa"];
  static SOAData cachedSD;
  static bool haveIt;

  if((target.size()-toLower(target).rfind(toLower(theSOA)))!=theSOA.size()) {
    //    cerr<<"target '"<<target<<"' does not end on '"<<theSOA<<"'"<<endl;
    return false;
  }
  if(!haveIt) {
    if(B.getSOA(arg()["only-soa"], cachedSD)) {
      cachedSD.qname=arg()["only-soa"];

      haveIt=true;
    }
  }
  if(haveIt) {
    *zoneId=sd->domain_id;  
    *sd=cachedSD;
  }
  return haveIt;
}

/** Determines if we are authoritative for a zone, and at what level */
bool PacketHandler::getAuth(DNSPacket *p, SOAData *sd, const string &target, int *zoneId)
{
  DNSResourceRecord rr;

  vector<string>parts;
  stringtok(parts,target,".");  // www.us.powerdns.com -> 'www' 'us' 'powerdns' 'com'
  
  unsigned int spos=0;
  string subdomain;
  // easy FIXME: convert this to chopOff
  while(spos<=parts.size()) {
    if(spos<parts.size()) { // www.us.powerdns.com -> us.powerdns.com -> powerdns.com -> com ->
      subdomain=parts[spos++];
      for(unsigned int i=spos;i<parts.size();++i) {
        subdomain+=".";
        subdomain+=parts[i];
      }
    }
    else {
      subdomain=""; // ROOT!
      spos++;
    }
    if(B.getSOA(subdomain, *sd)) {
      sd->qname=subdomain;
      *zoneId=sd->domain_id;
      return true;
    }
  }

  return false;
}

/** returns 1 in case of a straight match, 2 in case of a wildcard CNAME (groan), 0 in case of no hit */
int PacketHandler::doWildcardRecords(DNSPacket *p, DNSPacket *r, string &target)
{
  DNSResourceRecord rr;
  bool found=false, retargeted=false;

  // try chopping off domains and look for wildcard matches

  // *.pietje.nl IN  A 1.2.3.4
  // pietje.nl should now NOT match, but www.pietje.nl should

  string subdomain=target;
  unsigned int pos;
  while((pos=subdomain.find("."))!=string::npos) {
    subdomain=subdomain.substr(pos+1);
    // DLOG();

    string searchstr=string("*.")+subdomain;

    B.lookup(QType(QType::ANY), searchstr,p); // start our search at the backend

    while(B.get(rr)) { // read results
      found=true;
      if((p->qtype.getCode()==QType::ANY || rr.qtype==p->qtype) || rr.qtype.getCode()==QType::CNAME) {
        rr.qname=target;
        r->addRecord(rr);  // and add
        if(rr.qtype.getCode()==QType::CNAME) {
          if(target==rr.content) {
            L<<Logger::Error<<"Ignoring wildcard CNAME '"<<rr.qname<<"' pointing at itself"<<endl;
            r->setRcode(RCode::ServFail);
            continue;
          }
          
          DLOG(L<<Logger::Error<<"Retargeting because of wildcard cname, from "<<target<<" to "<<rr.content<<endl);
          
          target=rr.content; // retarget 
          retargeted=true;
        }
      }
      else if(d_doFancyRecords && arg().mustDo("wildcard-url") && p->qtype.getCode()==QType::A && rr.qtype.getName()=="URL") {
        rr.content=arg()["urlredirector"];
        rr.qtype=QType::A; 
        rr.qname=target;
        
        r->addRecord(rr);
      }
    }
    if(found) {
      DLOG(L<<"Wildcard match on '"<<string("*.")+subdomain<<"'"<<endl);
      return retargeted ? 2 : 1;
    }
  }
  return 0;
}

/** dangling is declared true if we were unable to resolve everything */
int PacketHandler::doAdditionalProcessingAndDropAA(DNSPacket *p, DNSPacket *r)
{
  DNSResourceRecord rr;
  SOAData sd;

  if(p->qtype.getCode()!=QType::AXFR && r->needAP()) { // this packet needs additional processing
    DLOG(L<<Logger::Warning<<"This packet needs additional processing!"<<endl);

    vector<DNSResourceRecord *> arrs=r->getAPRecords();
    for(vector<DNSResourceRecord *>::const_iterator i=arrs.begin();
        i!=arrs.end();
        ++i) {
      
      if((*i)->qtype.getCode()==QType::NS && !B.getSOA((*i)->qname,sd)) { // drop AA in case of non-SOA-level NS answer
        r->d.aa=false;
        (*i)->d_place=DNSResourceRecord::AUTHORITY;
      }

      QType qtypes[2];
      qtypes[0]="A"; qtypes[1]="AAAA";
      for(int n=0;n < d_doIPv6AdditionalProcessing + 1; ++n) {
        B.lookup(qtypes[n],(*i)->content,p);  
        bool foundOne=false;
        while(B.get(rr)) {
          foundOne=true;
          if(rr.domain_id!=(*i)->domain_id && arg()["out-of-zone-additional-processing"]=="no") {
            DLOG(L<<Logger::Warning<<"Not including out-of-zone additional processing of "<<(*i)->qname<<" ("<<rr.qname<<")"<<endl);
            continue; // not adding out-of-zone additional data
          }
          
          rr.d_place=DNSResourceRecord::ADDITIONAL;
          r->addRecord(rr);
          
        }
        if(!foundOne) {
          if(d_doRecursion && DP->recurseFor(p)) {
            try {
              Resolver resolver;
              resolver.resolve(arg()["recursor"],(*i)->content.c_str(),QType::A);
              Resolver::res_t res=resolver.result();
              for(Resolver::res_t::const_iterator j=res.begin();j!=res.end();++j) {
                if(j->d_place==DNSResourceRecord::ANSWER) {
                  rr=*j;
                  rr.d_place=DNSResourceRecord::ADDITIONAL;
                  r->addRecord(rr);
                }
              }
            }
            catch(ResolverException& re) {
              // L<<Logger::Error<<"Trying to do additional processing for answer to '"<<p->qdomain<<"' query: "<<re.reason<<endl;
            }
          }
        }
      }
    }
  }
  return 1;
}

/* returns 1 if everything is done & ready, 0 if the search should continue */
int PacketHandler::makeCanonic(DNSPacket *p, DNSPacket *r, string &target)
{
  DNSResourceRecord rr;

  bool found=false, rfound=false;

  if(p->qtype.getCode()!=QType::CNAME && !d_doCNAME)
    return 0;

  // Traverse a CNAME chain if needed
  for(int numloops=0;;numloops++) {
    if(numloops==10) {
      L<<Logger::Error<<"Detected a CNAME loop involving "<<target<<", sending SERVFAIL"<<endl;
      r->setRcode(2);
      return 1;
    }

    B.lookup(QType(QType::ANY),target,p);
        
    bool shortcut=p->qtype.getCode()!=QType::SOA && p->qtype.getCode()!=QType::ANY;

    while(B.get(rr)) {
      if(!rfound && rr.qtype.getCode()==QType::CNAME) {
        found=true;
        r->addRecord(rr);
        target=rr.content; // for retargeting
      }
      if(shortcut && !found && rr.qtype==p->qtype) {
        rfound=true;
        r->addRecord(rr);
      }
    }
    if(rfound)
      return 1; // ANY lookup found the right answer immediately

    if(found) {
      if(p->qtype.getCode()==QType::CNAME) // they really wanted a CNAME!
        return 1;
      DLOG(L<<"Looping because of a CNAME to "<<target<<endl);
      found=false;
    }
    else break;
  }

  // we now have what we really search for ready in 'target'
  return 0;
}

/* Semantics:
   
- only one backend owns the SOA of a zone
- only one AXFR per zone at a time - double startTransaction should fail
- backends need to implement transaction semantics


How BindBackend would implement this:
   startTransaction makes a file 
   feedRecord sends everything to that file 
   commitTransaction moves that file atomically over the regular file, and triggers a reload
   rollbackTransaction removes the file


How PostgreSQLBackend would implement this:
   startTransaction starts a sql transaction, which also deletes all records
   feedRecord is an insert statement
   commitTransaction commits the transaction
   rollbackTransaction aborts it

How MySQLBackend would implement this:
   (good question!)
   
*/     

int PacketHandler::trySuperMaster(DNSPacket *p)
{
  Resolver::res_t nsset;
  try {
    Resolver resolver;
    u_int32_t theirserial;
    int res=resolver.getSoaSerial(p->getRemote(),p->qdomain, &theirserial);  
    if(res<=0) {
      L<<Logger::Error<<"Unable to determine SOA serial for "<<p->qdomain<<" at potential supermaster "<<p->getRemote()<<endl;
      return RCode::ServFail;
    }
  
    resolver.resolve(p->getRemote(),p->qdomain.c_str(), QType::NS);

    nsset=resolver.result();
  }
  catch(ResolverException &re) {
    L<<Logger::Error<<"Error resolving SOA or NS for '"<<p->qdomain<<"' at "<<p->getRemote()<<endl;
    return RCode::ServFail;
  }

  string account;
  DNSBackend *db;
  if(!B.superMasterBackend(p->getRemote(), p->qdomain, nsset, &account, &db)) {
   L<<Logger::Error<<"Unable to find backend willing to host "<<p->qdomain<<" for potential supermaster "<<p->getRemote()<<endl;
    return RCode::Refused;
  }
  db->createSlaveDomain(p->getRemote(),p->qdomain,account);
  Communicator.addSuckRequest(p->qdomain, p->getRemote());  
  L<<Logger::Warning<<"Created new slave zone '"<<p->qdomain<<"' from supermaster "<<p->getRemote()<<", queued axfr"<<endl;
  return RCode::NoError;
}

int PacketHandler::doNotify(DNSPacket *p)
{
  /* now what? 
     was this notification from an approved address?
     We determine our internal SOA id (via UeberBackend)
     We determine the SOA at our (known) master
     if master is higher -> do stuff
  */
  if(!arg().mustDo("slave")) {
    L<<Logger::Error<<"Received NOTIFY for "<<p->qdomain<<" from "<<p->getRemote()<<" but slave support is disabled in the configuration"<<endl;
    return RCode::NotImp;
  }
  DNSBackend *db=0;
  DomainInfo di;
  if(!B.getDomainInfo(p->qdomain,di) || !(db=di.backend)) {
    L<<Logger::Error<<"Received NOTIFY for "<<p->qdomain<<" from "<<p->getRemote()<<" for which we are not authoritative"<<endl;
    return trySuperMaster(p);
  }
    
  if(!db->isMaster(p->qdomain, p->getRemote())) {
    L<<Logger::Error<<"Received NOTIFY for "<<p->qdomain<<" from "<<p->getRemote()<<" which is not a master"<<endl;
    return RCode::Refused;
  }

  u_int32_t theirserial=0;

  Resolver resolver;
  int res=resolver.getSoaSerial(p->getRemote(),p->qdomain, &theirserial);
  if(res<=0) {
    L<<Logger::Error<<"Unable to determine SOA serial for "<<p->qdomain<<" at "<<p->getRemote()<<endl;
    return RCode::ServFail;
  }
        

  if(theirserial<=di.serial) {
    L<<Logger::Error<<"Received NOTIFY for "<<p->qdomain<<" from master "<<p->getRemote()<<", we are up to date: "<<
      theirserial<<"<="<<di.serial<<endl;
    return RCode::NoError;
  }
  else {
    L<<Logger::Error<<"Received valid NOTIFY for "<<p->qdomain<<" (id="<<di.id<<") from master "<<p->getRemote()<<": "<<
      theirserial<<" > "<<di.serial<<endl;

    Communicator.addSuckRequest(p->qdomain, p->getRemote());
  }
  return -1; 
}


//! Called by the Distributor to ask a question. Returns 0 in case of an error
DNSPacket *PacketHandler::question(DNSPacket *p)
{
  DNSResourceRecord rr;
  SOAData sd;
  
  string subdomain="";
  string soa;
  int retargetcount=0;
  bool noSameLevelNS;

  DNSPacket *r=0;
  try {    
    DLOG(L << Logger::Notice<<"Remote "<<inet_ntoa( reinterpret_cast< struct sockaddr_in * >( &( p->remote ))->sin_addr )<<" wants a type " << p->qtype.getName() << " ("<<p->qtype.getCode()<<") about '"<<p->qdomain << "'" << endl);

// XXX FIXME Find out why this isn't working!
#ifndef WIN32
    if(p->d.qr) { // QR bit from dns packet (thanks RA from N)
      L<<Logger::Error<<"Received an answer (non-query) packet from "<<p->getRemote()<<", dropping"<<endl;
      S.inc("corrupt-packets");
      return 0;
    }
#endif // WIN32

    // XXX FIXME do this in DNSPacket::parse ?

    if(!p->qdomain.empty() && (p->qdomain[0]=='%' || p->qdomain.find('|')!=string::npos) ) {
      L<<Logger::Error<<"Received a malformed qdomain from "<<p->getRemote()<<", '"<<p->qdomain<<"': dropping"<<endl;
      S.inc("corrupt-packets");
      return 0;
    }
    if(p->d.opcode) { // non-zero opcode (again thanks RA!)
      if(p->d.opcode==Opcode::Update) {
        if(arg().mustDo("log-failed-updates"))
          L<<Logger::Notice<<"Received an UPDATE opcode from "<<p->getRemote()<<" for "<<p->qdomain<<", sending NOTIMP"<<endl;
        r=p->replyPacket(); 
        r->setRcode(RCode::NotImp); // notimp;
        return r; 
      }
      else if(p->d.opcode==Opcode::Notify) {
        int res=doNotify(p);
        if(res>=0) {
          DNSPacket *r=p->replyPacket();
          r->setRcode(res);
          return r;
        }
        return 0;
      }
      
      L<<Logger::Error<<"Received an unknown opcode "<<p->d.opcode<<" from "<<p->getRemote()<<" for "<<p->qdomain<<endl;

      r=p->replyPacket(); 
      r->setRcode(RCode::NotImp); 
      return r; 
    }
    
    r=p->replyPacket();  // generate an empty reply packet

    if(p->qtype.getCode()==QType::IXFR) {
      r->setRcode(RCode::NotImp);
      return r;
    }

    bool found=false;
    
    string target=p->qdomain;
    
    if (doDNSCheckRequest(p, r, target))
      goto sendit;
    
    if(doVersionRequest(p,r,target)) // catch version.bind requests
      goto sendit;

    if(p->qclass==255) // any class query 
      r->setA(false);
    else if(p->qclass!=1) // we only know about IN, so we don't find anything
      goto sendit;

  retargeted:;
    if(retargetcount++>10) {
      L<<Logger::Error<<"Detected wildcard CNAME loop involving '"<<target<<"'"<<endl;
      r->setRcode(RCode::ServFail);
      goto sendit;
    }

    if(makeCanonic(p,r,target)>0) // traverse CNAME chain until we have a useful record (may actually give the correct answer!)
      goto sendit; // this might be the end of it (client requested a CNAME, or we found the answer already)
    
    if(d_doFancyRecords) { // MBOXFW, URL <- fake records, emulated with MX and A
      int res=doFancyRecords(p,r,target);
      if(res) { // had a result
        if(res<0) // it was an error
          r->setRcode(RCode::ServFail);
        goto sendit;  
      }
    }
    
    // now ready to start the real direct search

    if(p->qtype.getCode()==QType::SOA || p->qtype.getCode()==QType::ANY) { // this is special

      if(B.getSOA(target,sd)) {
        rr.qname=target;
        rr.qtype=QType::SOA;
        rr.content=DNSPacket::serializeSOAData(sd);
        rr.ttl=sd.ttl;
        rr.domain_id=sd.domain_id;
        rr.d_place=DNSResourceRecord::ANSWER;
        r->addRecord(rr);
        if(p->qtype.getCode()==QType::SOA) { // we are done
          goto sendit;
        }
      }
    }

    noSameLevelNS=true;

    if(p->qtype.getCode()!=QType::SOA) { // regular direct lookup
      B.lookup(QType(QType::ANY), target,p);
      
      while(B.get(rr)) {
        if(rr.qtype.getCode()==QType::SOA) // skip any direct SOA responses as they may be different
          continue;
        if(rr.qtype==p->qtype || p->qtype.getCode()==QType::ANY ) {
          DLOG(L<<"Found a direct answer: "<<rr.content<<endl);
          found=true;
          r->addRecord(rr);  // and add
        }
        else
          if(rr.qtype.getCode()==QType::NS)
            noSameLevelNS=false;
      }
      
      if(p->qtype.getCode()==QType::ANY) {
        if(d_doFancyRecords) { 
          int res=findMboxFW(p,r,target);
          if(res<0)
            L<<Logger::Error<<"Error finding a mailbox record after an ANY query"<<endl;
          if(res>0) {
            DLOG(L<<Logger::Error<<"Frobbed an MX in!"<<endl);
            found=true;
          }
        }
      }
      if(found) 
        goto sendit;
      
    }
    
    // not found yet, try wildcards (we only try here in case of recursion - we should check before we hand off)

    if(p->d.rd && d_doRecursion && d_doWildcards) { 
      int res=doWildcardRecords(p,r,target);
      if(res) { // had a result
        // FIXME: wildCard may retarget us in the future
        if(res==1)  // had a straight result
          goto sendit;  
        if(res==2)
          goto retargeted;
        goto sendit;  
      }
    }

    // RECURSION CUT-OUT! 

    if(p->d.rd && d_doRecursion && DP->sendPacket(p)) {
      delete r;
      return 0;
    }

    unsigned int pos;
    
    DLOG(L<<"Nothing found so far for '"<<target<<"', do we even have authority over this domain?"<<endl);
    
    bool weAuth;
    int zoneId;

    weAuth=getAuth(p, &sd, target, &zoneId); // TLDAuth perhaps
    if(weAuth) {
      DLOG(L<<Logger::Warning<<"Soa found: "<<soa<<endl);
      ;
    }
    if(!weAuth) {
      if(p->d.rd || target==p->qdomain) { // only servfail if we didn't follow a CNAME
        if(d_logDNSDetails)
          L<<Logger::Warning<<"Not authoritative for '"<< target<<"', sending servfail to "<<
            p->getRemote()<< (p->d.rd ? " (recursion was desired)" : "") <<endl;

        r->setA(false);
        r->setRcode(RCode::ServFail);  // 'sorry' - this is where we might send out a root referral
      }
                                       
      S.ringAccount("unauth-queries",p->qdomain+"/"+p->qtype.getName());
      S.ringAccount("remotes-unauth",p->getRemote());
    }
    else {
      DLOG(L<<Logger::Warning<<"We ARE authoritative for a subdomain of '"<<target<<"' ("<<sd.qname<<"), perhaps we have a suitable NS record then"<<endl);
      subdomain=target;
      found=0;
      pos=0; 
      
      do {
        if(pos) // skip dot
          pos++;
        
        subdomain=subdomain.substr(pos);
        if(noSameLevelNS) { // skip first lookup if it is known not to exist
          noSameLevelNS=false;
          continue;
        }
          
        if(!Utility::strcasecmp(subdomain.c_str(),sd.qname.c_str())) // about to break out of our zone
          break; 

        B.lookup("NS", subdomain,p,zoneId);  // start our search at the backend
        
        while(B.get(rr)) {
          found=true;
          rr.d_place=DNSResourceRecord::AUTHORITY; // this for the authority section
          r->addRecord(rr);
        }
        if(found || (!subdomain.empty() && subdomain[0]=='.')) {  // this catches '..'
          r->setA(false);  // send out an NS referral, which should be unauth
          break;
        }
      }while((pos=subdomain.find("."))!=string::npos);
      
      if(!found) {
        // try wildcards then 
        if(d_doWildcards) { 
          int res=doWildcardRecords(p,r,target);

          if(res==1)  // had a straight result
            goto sendit; 
          if(res==2)
            goto retargeted;
        }

        // we have authority but no answer, so we add the SOA for negative caching
        rr.qname=sd.qname;
        rr.qtype=QType::SOA;
        rr.content=DNSPacket::serializeSOAData(sd);
        rr.ttl=sd.ttl;
        rr.domain_id=sd.domain_id;
        rr.d_place=DNSResourceRecord::AUTHORITY;
        r->addRecord(rr);


        // need to send NXDOMAIN if there are 0 records for whatever type for target
        
        B.lookup("ANY",target,p);
        while(B.get(rr))
          found=true;
        
        if(!found) {
          SOAData sd2;
          if(B.getSOA(target,sd2)) // is there a SOA perhaps? (which may not appear in an ANY query)
            found=true;
        }

        if(!found) { 
          if(d_logDNSDetails)
            L<<Logger::Notice<<"Authoritative NXDOMAIN to "<< p->getRemote() <<" for '"<<target<<"' ("<<p->qtype.getName()<<")"<<endl;

          r->setRcode(RCode::NXDomain); 
          S.ringAccount("nxdomain-queries",p->qdomain+"/"+p->qtype.getName());
        }
        else {
          if(d_logDNSDetails)
            L<<Logger::Notice<<"Authoritative empty NO ERROR to "<< p->getRemote() <<" for '"<<target<<"' ("<<p->qtype.getName()<<"), other types do exist"<<endl;
          S.ringAccount("noerror-queries",p->qdomain+"/"+p->qtype.getName());
        }
      }
    }
    
    // whatever we've built so far, do additional processing
    
  sendit:;

    if(doAdditionalProcessingAndDropAA(p,r)<0)
      return 0;
    

    r->wrapup(); // needed for inserting in cache
    PC.insert(p,r); // in the packet cache
  }
  catch(DBException &e) {
    L<<Logger::Error<<"Database module reported condition which prevented lookup - sending out servfail"<<endl;
    r->setRcode(RCode::ServFail);
    S.inc("servfail-packets");
    S.ringAccount("servfail-queries",p->qdomain);
  }
  return r; 

}