DNS.hpp

   1 #ifndef DNS_DOT_HPP
   2 #define DNS_DOT_HPP
   3
   4 #include <memory>
   5
   6 #include "DNS-message.hpp"
   7 #include "DNS-rrs.hpp"
   8 #include "Sock.hpp"
   9 #include "iobuffer.hpp"
  10
  11 #include <glog/logging.h>
  12
  13 #include "pcg.hpp"
  14
  15 namespace DNS {
  16
  17 class Resolver {
  18 public:
  19   Resolver(Resolver const&)            = delete;
  20   Resolver& operator=(Resolver const&) = delete;
  21
  22   Resolver(fs::path config_path);
  23
  24   RR_collection get_records(RR_type typ, char const* name);
  25   RR_collection get_records(RR_type typ, std::string const& name)
  26   {
  27     return get_records(typ, name.c_str());
  28   }
  29
  30   std::vector<std::string> get_strings(RR_type typ, char const* name);
  31   std::vector<std::string> get_strings(RR_type typ, std::string const& name)
  32   {
  33     return get_strings(typ, name.c_str());
  34   }
  35
  36   message xchg(message const& q);
  37
  38   uint16_t rnd_id()
  39   {
  40     static_assert(std::numeric_limits<uint16_t>::min() == 0);
  41     static_assert(std::numeric_limits<uint16_t>::max() == 65535);
  42     std::uniform_int_distribution<int> uniform_dist(0, 65535);
  43     return uniform_dist(rng_);
  44   }
  45
  46 private:
  47   std::unique_ptr<Sock> ns_sock_;
  48   int                   ns_;
  49   int                   ns_fd_;
  50
  51   inline static pcg_extras::seed_seq_from<std::random_device> seed_source_;
  52   inline static pcg32 rng_{seed_source_};
  53 };
  54
  55 class Query {
  56 public:
  57   Query(Query const&)            = delete;
  58   Query& operator=(Query const&) = delete;
  59
  60   Query(Resolver& res, RR_type type, char const* name);
  61   Query(Resolver& res, RR_type type, std::string const& name)
  62     : Query(res, type, name.c_str())
  63   {
  64   }
  65
  66   bool authentic_data() const { return authentic_data_; }
  67   bool bogus_or_indeterminate() const { return bogus_or_indeterminate_; }
  68   bool truncation() const { return truncation_; }
  69   bool nx_domain() const { return nx_domain_; }
  70
  71   bool                     has_record() const { return has_record_; }
  72   RR_collection            get_records();
  73   std::vector<std::string> get_strings();
  74
  75   uint16_t rcode() const { return rcode_; }
  76   uint16_t extended_rcode() const { return extended_rcode_; }
  77
  78 private:
  79   bool xchg_(Resolver& res, uint16_t id);
  80   void check_answer_(Resolver& res, RR_type type, char const* name);
  81
  82   uint16_t rcode_{0};
  83   uint16_t extended_rcode_{0};
  84
  85   RR_type type_;
  86
  87   message q_;
  88   message a_;
  89
  90   bool authentic_data_{false};
  91   bool bogus_or_indeterminate_{false};
  92   bool truncation_{false};
  93   bool nx_domain_{false};
  94   bool has_record_{false};
  95 };
  96
  97 inline std::vector<std::string>
  98 get_strings(Resolver& res, RR_type type, char const* name)
  99 {
 100   return res.get_strings(type, name);
 101 }
 102
 103 inline std::vector<std::string>
 104 get_strings(Resolver& res, RR_type type, std::string const& name)
 105 {
 106   return res.get_strings(type, name.c_str());
 107 }
 108
 109 inline bool has_record(Resolver& res, RR_type type, char const* name)
 110 {
 111   Query q(res, type, name);
 112   return q.has_record();
 113 }
 114
 115 inline bool has_record(Resolver& res, RR_type type, std::string const& name)
 116 {
 117   return has_record(res, type, name.c_str());
 118 }
 119 } // namespace DNS
 120
 121 #endif // DNS_DOT_HPP