pdns/dns.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 "dns.hh"
  26 #include "misc.hh"
  27 #include <stdexcept>
  28 #include <iostream>
  29 #include <boost/algorithm/string.hpp>
  30 #include <boost/assign/list_of.hpp>
  31 #include "dnsparser.hh"
  32
  33 std::vector<std::string> RCode::rcodes_s = boost::assign::list_of
  34   ("No Error")
  35   ("Form Error")
  36   ("Server Failure")
  37   ("Non-Existent domain")
  38   ("Not Implemented")
  39   ("Query Refused")
  40   ("Name Exists when it should not")
  41   ("RR Set Exists when it should not")
  42   ("RR Set that should exist does not")
  43   ("Server Not Authoritative for zone / Not Authorized")
  44   ("Name not contained in zone")
  45   ("Err#11")
  46   ("Err#12")
  47   ("Err#13")
  48   ("Err#14")
  49   ("Err#15")
  50   ("Bad OPT Version / TSIG Signature Failure")
  51   ("Key not recognized")
  52   ("Signature out of time window")
  53   ("Bad TKEY Mode")
  54   ("Duplicate key name")
  55   ("Algorithm not supported")
  56   ("Bad Truncation")
  57 ;
  58
  59 std::string RCode::to_s(unsigned short rcode) {
  60   if (rcode > RCode::rcodes_s.size()-1 )
  61     return std::string("Err#")+std::to_string(rcode);
  62   return RCode::rcodes_s[rcode];
  63 }
  64
  65 class BoundsCheckingPointer
  66 {
  67 public:
  68   explicit BoundsCheckingPointer(const char* a, size_t length)
  69     : d_ptr(a), d_length(length)
  70     {}
  71
  72   explicit BoundsCheckingPointer(const std::string& str)
  73     : d_ptr(str.c_str()), d_length(str.size())
  74     {}
  75
  76
  77   char operator[](size_t offset) const
  78   {
  79     if(offset < d_length)
  80       return d_ptr[offset];
  81     throw runtime_error("out of bounds: "+std::to_string(offset)+" >= " + std::to_string(d_length));
  82   }
  83 private:
  84   const char* d_ptr;
  85   const size_t d_length;
  86 };
  87
  88
  89 // goal is to hash based purely on the question name, and turn error into 'default'
  90 uint32_t hashQuestion(const char* packet, uint16_t len, uint32_t init)
  91 {
  92   if(len < 12)
  93     return init;
  94
  95   uint32_t ret=init;
  96   const unsigned char* end = (const unsigned char*)packet+len;
  97   const unsigned char* pos = (const unsigned char*)packet+12;
  98
  99   unsigned char labellen;
 100   while((labellen=*pos++) && pos < end) {
 101     if(pos + labellen + 1 > end) // include length field  in hash
 102       return 0;
 103     ret=burtleCI(pos, labellen+1, ret);
 104     pos += labellen;
 105   }
 106   return ret;
 107 }
 108
 109
 110 string& attodot(string &str)
 111 {
 112    if(str.find_first_of("@")==string::npos)
 113       return str;
 114
 115    for (unsigned int i = 0; i < str.length(); i++)
 116    {
 117       if (str[i] == '@') {
 118          str[i] = '.';
 119          break;
 120       } else if (str[i] == '.') {
 121          str.insert(i++, "\\");
 122       }
 123    }
 124    return str;
 125 }
 126
 127 vector<DNSResourceRecord> convertRRS(const vector<DNSRecord>& in)
 128 {
 129   vector<DNSResourceRecord> out;
 130   for(const auto& d : in) {
 131     DNSResourceRecord rr;
 132     rr.qname = d.d_name;
 133     rr.qtype = QType(d.d_type);
 134     rr.ttl = d.d_ttl;
 135     rr.content = d.d_content->getZoneRepresentation();
 136     rr.auth = false;
 137     rr.qclass = d.d_class;
 138     out.push_back(rr);
 139   }
 140   return out;
 141 }