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")  // Last non-extended RCode
  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   ("Bad/missing Server Cookie")
  58 ;
  59
  60 std::string RCode::to_s(uint8_t rcode) {
  61   if (rcode > 0xF)
  62     return std::string("ErrOutOfRange");
  63   return ERCode::to_s(rcode);
  64 }
  65
  66 std::string ERCode::to_s(uint8_t rcode) {
  67   if (rcode > RCode::rcodes_s.size()-1)
  68     return std::string("Err#")+std::to_string(rcode);
  69   return RCode::rcodes_s[rcode];
  70 }
  71
  72 std::string Opcode::to_s(uint8_t opcode) {
  73   static const std::vector<std::string> s_opcodes = { "Query", "IQuery", "Status", "3", "Notify", "Update" };
  74
  75   if (opcode >= s_opcodes.size()) {
  76     return std::to_string(opcode);
  77   }
  78
  79   return s_opcodes.at(opcode);
  80 }
  81
  82 class BoundsCheckingPointer
  83 {
  84 public:
  85   explicit BoundsCheckingPointer(const char* a, size_t length)
  86     : d_ptr(a), d_length(length)
  87     {}
  88
  89   explicit BoundsCheckingPointer(const std::string& str)
  90     : d_ptr(str.c_str()), d_length(str.size())
  91     {}
  92
  93
  94   char operator[](size_t offset) const
  95   {
  96     if(offset < d_length)
  97       return d_ptr[offset];
  98     throw runtime_error("out of bounds: "+std::to_string(offset)+" >= " + std::to_string(d_length));
  99   }
 100 private:
 101   const char* d_ptr;
 102   const size_t d_length;
 103 };
 104
 105
 106 // goal is to hash based purely on the question name, and turn error into 'default'
 107 uint32_t hashQuestion(const char* packet, uint16_t len, uint32_t init)
 108 {
 109   if(len < 12)
 110     return init;
 111
 112   uint32_t ret=init;
 113   const unsigned char* end = (const unsigned char*)packet+len;
 114   const unsigned char* pos = (const unsigned char*)packet+12;
 115
 116   unsigned char labellen;
 117   while((labellen=*pos++) && pos < end) {
 118     if(pos + labellen + 1 > end) // include length field  in hash
 119       return 0;
 120     ret=burtleCI(pos, labellen+1, ret);
 121     pos += labellen;
 122   }
 123   return ret;
 124 }
 125
 126
 127 string& attodot(string &str)
 128 {
 129    if(str.find_first_of("@")==string::npos)
 130       return str;
 131
 132    for (unsigned int i = 0; i < str.length(); i++)
 133    {
 134       if (str[i] == '@') {
 135          str[i] = '.';
 136          break;
 137       } else if (str[i] == '.') {
 138          str.insert(i++, "\\");
 139       }
 140    }
 141    return str;
 142 }