pdns/ixfrutils.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
  23 #include <cinttypes>
  24 #include <dirent.h>
  25 #include <cerrno>
  26 #include "ixfrutils.hh"
  27 #include "sstuff.hh"
  28 #include "dnssecinfra.hh"
  29 #include "zoneparser-tng.hh"
  30 #include "dnsparser.hh"
  31
  32 uint32_t getSerialFromMaster(const ComboAddress& master, const DNSName& zone, shared_ptr<SOARecordContent>& sr, const TSIGTriplet& tt, const uint16_t timeout)
  33 {
  34   vector<uint8_t> packet;
  35   DNSPacketWriter pw(packet, zone, QType::SOA);
  36   if(!tt.algo.empty()) {
  37     TSIGRecordContent trc;
  38     trc.d_algoName = tt.algo;
  39     trc.d_time = time(nullptr);
  40     trc.d_fudge = 300;
  41     trc.d_origID=ntohs(pw.getHeader()->id);
  42     trc.d_eRcode=0;
  43     addTSIG(pw, trc, tt.name, tt.secret, "", false);
  44   }
  45
  46   Socket s(master.sin4.sin_family, SOCK_DGRAM);
  47   s.connect(master);
  48   string msg((const char*)&packet[0], packet.size());
  49   s.writen(msg);
  50
  51   string reply;
  52   reply.resize(4096);
  53   // will throw a NetworkError on timeout
  54   ssize_t got = s.readWithTimeout(&reply[0], reply.size(), timeout);
  55   if (got < 0 || static_cast<size_t>(got) < sizeof(dnsheader)) {
  56     throw std::runtime_error("Invalid response size " + std::to_string(got));
  57   }
  58
  59   reply.resize(got);
  60
  61   MOADNSParser mdp(false, reply);
  62   if(mdp.d_header.rcode) {
  63     throw std::runtime_error("RCODE from response is not NoError but " + RCode::to_s(mdp.d_header.rcode));
  64   }
  65   for(const auto& r: mdp.d_answers) {
  66     if(r.first.d_type == QType::SOA) {
  67       sr = getRR<SOARecordContent>(r.first);
  68       if(sr != nullptr) {
  69         return sr->d_st.serial;
  70       }
  71     }
  72   }
  73   return 0;
  74 }
  75
  76 uint32_t getSerialFromDir(const std::string& dir)
  77 {
  78   uint32_t ret=0;
  79   DIR* dirhdl=opendir(dir.c_str());
  80   if(!dirhdl)
  81     throw runtime_error("Could not open IXFR directory '" + dir + "': " + stringerror());
  82   struct dirent *entry;
  83
  84   while((entry = readdir(dirhdl))) {
  85     uint32_t num = atoi(entry->d_name);
  86     if(std::to_string(num) == entry->d_name)
  87       ret = max(num, ret);
  88   }
  89   closedir(dirhdl);
  90   return ret;
  91 }
  92
  93 uint32_t getSerialFromRecords(const records_t& records, DNSRecord& soaret)
  94 {
  95   uint16_t t=QType::SOA;
  96
  97   auto found = records.equal_range(std::tie(g_rootdnsname, t));
  98
  99   for(auto iter = found.first; iter != found.second; ++iter) {
 100     auto soa = std::dynamic_pointer_cast<SOARecordContent>(iter->d_content);
 101     if (soa) {
 102       soaret = *iter;
 103       return soa->d_st.serial;
 104     }
 105   }
 106   return 0;
 107 }
 108
 109 static void writeRecords(FILE* fp, const records_t& records)
 110 {
 111   for(const auto& r: records) {
 112     if(fprintf(fp, "%s\t%" PRIu32 "\tIN\t%s\t%s\n",
 113             r.d_name.isRoot() ? "@" :  r.d_name.toStringNoDot().c_str(),
 114             r.d_ttl,
 115             DNSRecordContent::NumberToType(r.d_type).c_str(),
 116             r.d_content->getZoneRepresentation().c_str()) < 0) {
 117       throw runtime_error(stringerror());
 118     }
 119   }
 120 }
 121
 122 void writeZoneToDisk(const records_t& records, const DNSName& zone, const std::string& directory)
 123 {
 124   DNSRecord soa;
 125   auto serial = getSerialFromRecords(records, soa);
 126   string fname=directory +"/"+std::to_string(serial);
 127   auto fp = std::unique_ptr<FILE, int(*)(FILE*)>(fopen((fname+".partial").c_str(), "w"), fclose);
 128   if (!fp) {
 129     throw runtime_error("Unable to open file '"+fname+".partial' for writing: "+stringerror());
 130   }
 131
 132   records_t soarecord;
 133   soarecord.insert(soa);
 134   if (fprintf(fp.get(), "$ORIGIN %s\n", zone.toString().c_str()) < 0) {
 135     string error = "Error writing to zone file for " + zone.toLogString() + " in file " + fname + ".partial" + ": " + stringerror();
 136     fp.reset();
 137     unlink((fname+".partial").c_str());
 138     throw std::runtime_error(error);
 139   }
 140
 141   try {
 142     writeRecords(fp.get(), soarecord);
 143     writeRecords(fp.get(), records);
 144     writeRecords(fp.get(), soarecord);
 145   } catch (runtime_error &e) {
 146     fp.reset();
 147     unlink((fname+".partial").c_str());
 148     throw runtime_error("Error closing zone file for " + zone.toLogString() + " in file " + fname + ".partial" + ": " + e.what());
 149   }
 150
 151   if (fclose(fp.release()) != 0) {
 152     string error = "Error closing zone file for " + zone.toLogString() + " in file " + fname + ".partial" + ": " + stringerror();
 153     unlink((fname+".partial").c_str());
 154     throw std::runtime_error(error);
 155   }
 156
 157   if (rename( (fname+".partial").c_str(), fname.c_str()) != 0) {
 158     throw std::runtime_error("Unable to move the zone file for " + zone.toLogString() + " from " + fname + ".partial to " + fname + ": " + stringerror());
 159   }
 160 }
 161
 162 void loadZoneFromDisk(records_t& records, const string& fname, const DNSName& zone)
 163 {
 164   ZoneParserTNG zpt(fname, zone);
 165
 166   zpt.disableGenerate();
 167   DNSResourceRecord rr;
 168   bool seenSOA=false;
 169   while(zpt.get(rr)) {
 170     if(rr.qtype.getCode() == QType::CNAME && rr.content.empty())
 171       rr.content=".";
 172     rr.qname = rr.qname.makeRelative(zone);
 173
 174     if(rr.qtype.getCode() != QType::SOA || seenSOA==false)
 175       records.insert(DNSRecord(rr));
 176     if(rr.qtype.getCode() == QType::SOA) {
 177       seenSOA=true;
 178     }
 179   }
 180   if(!(rr.qtype.getCode() == QType::SOA && seenSOA)) {
 181     records.clear();
 182     throw runtime_error("Zone not complete!");
 183   }
 184 }
 185
 186 /*
 187  * Load the zone `zone` from `fname` and put the first found SOA into `soa`
 188  * Does NOT check for nullptr
 189  */
 190 void loadSOAFromDisk(const DNSName& zone, const string& fname, shared_ptr<SOARecordContent>& soa, uint32_t& soaTTL)
 191 {
 192   ZoneParserTNG zpt(fname, zone);
 193   zpt.disableGenerate();
 194   DNSResourceRecord rr;
 195
 196   while(zpt.get(rr)) {
 197     if (rr.qtype == QType::SOA) {
 198       soa = getRR<SOARecordContent>(DNSRecord(rr));
 199       soaTTL = rr.ttl;
 200       return;
 201     }
 202   }
 203 }