modules/randombackend/randombackend.cc

   1 /*
   2  * This file is part of PowerDNS or dnsdist.
   3  * Copyright -- PowerDNS.COM B.V. and its contributors
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of version 2 of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * In addition, for the avoidance of any doubt, permission is granted to
  10  * link this program with OpenSSL and to (re)distribute the binaries
  11  * produced as the result of such linking.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25 #include "pdns/utility.hh"
  26 #include "pdns/dnsbackend.hh"
  27 #include "pdns/dns.hh"
  28 #include "pdns/dnsbackend.hh"
  29 #include "pdns/dnspacket.hh"
  30 #include "pdns/pdnsexception.hh"
  31 #include "pdns/logger.hh"
  32 #include "pdns/version.hh"
  33 #include <boost/algorithm/string.hpp>
  34
  35 /* FIRST PART */
  36 class RandomBackend : public DNSBackend
  37 {
  38 public:
  39   RandomBackend(const string &suffix="")
  40   {
  41     setArgPrefix("random"+suffix);
  42     d_ourname=DNSName(getArg("hostname"));
  43     d_ourdomain = d_ourname;
  44     d_ourdomain.chopOff();
  45   }
  46
  47   bool list(const DNSName &target, int id, bool include_disabled) {
  48     return false; // we don't support AXFR
  49   }
  50
  51   void lookup(const QType &type, const DNSName &qdomain, DNSPacket *p, int zoneId)
  52   {
  53     if(qdomain == d_ourdomain){
  54       if(type.getCode() == QType::SOA || type.getCode() == QType::ANY) {
  55         d_answer="ns1." + d_ourdomain.toString() + " hostmaster." + d_ourdomain.toString() + " 1234567890 86400 7200 604800 300";
  56       } else {
  57         d_answer="";
  58       }
  59     } else if (qdomain == d_ourname) {
  60       if(type.getCode() == QType::A || type.getCode() == QType::ANY) {
  61         ostringstream os;
  62         os<<Utility::random()%256<<"."<<Utility::random()%256<<"."<<Utility::random()%256<<"."<<Utility::random()%256;
  63         d_answer=os.str(); // our random ip address
  64       } else {
  65         d_answer="";
  66       }
  67     } else {
  68       d_answer="";
  69     }
  70   }
  71
  72   bool get(DNSResourceRecord &rr)
  73   {
  74     if(!d_answer.empty()) {
  75       if(d_answer.find("ns1.") == 0){
  76         rr.qname=d_ourdomain;
  77         rr.qtype=QType::SOA;
  78       } else {
  79         rr.qname=d_ourname;
  80         rr.qtype=QType::A;
  81       }
  82       rr.ttl=5;             // 5 seconds
  83       rr.auth = 1;          // it may be random.. but it is auth!
  84       rr.content=d_answer;
  85
  86       d_answer="";          // this was the last answer
  87       return true;
  88     }
  89     return false;
  90   }
  91
  92 private:
  93   string d_answer;
  94   DNSName d_ourname;
  95   DNSName d_ourdomain;
  96 };
  97
  98 /* SECOND PART */
  99
 100 class RandomFactory : public BackendFactory
 101 {
 102 public:
 103   RandomFactory() : BackendFactory("random") {}
 104   void declareArguments(const string &suffix="")
 105   {
 106     declare(suffix,"hostname","Hostname which is to be random","random.example.com");
 107   }
 108   DNSBackend *make(const string &suffix="")
 109   {
 110     return new RandomBackend(suffix);
 111   }
 112 };
 113
 114 /* THIRD PART */
 115
 116 class RandomLoader
 117 {
 118 public:
 119   RandomLoader()
 120   {
 121     BackendMakers().report(new RandomFactory);
 122     L << Logger::Info << "[randombackend] This is the random backend version " VERSION
 123 #ifndef REPRODUCIBLE
 124       << " (" __DATE__ " " __TIME__ ")"
 125 #endif
 126       << " reporting" << endl;
 127   }
 128 };
 129
 130 static RandomLoader randomLoader;