pdns/recpacketcache.hh

   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 #ifndef PDNS_RECPACKETCACHE_HH
  23 #define PDNS_RECPACKETCACHE_HH
  24 #include <string>
  25 #include <set>
  26 #include <inttypes.h>
  27 #include "dns.hh"
  28 #include "namespaces.hh"
  29 #include <iostream>
  30 #include <boost/multi_index_container.hpp>
  31 #include <boost/multi_index/ordered_index.hpp>
  32 #include <boost/multi_index/hashed_index.hpp>
  33 #include <boost/tuple/tuple_comparison.hpp>
  34 #include <boost/multi_index/sequenced_index.hpp>
  35
  36 #ifdef HAVE_CONFIG_H
  37 #include "config.h"
  38 #endif
  39 #include "rec-protobuf.hh"
  40
  41
  42 using namespace ::boost::multi_index;
  43
  44 //! Stores whole packets, ready for lobbing back at the client. Not threadsafe.
  45 /* Note: we store answers as value AND KEY, and with careful work, we make sure that
  46    you can use a query as a key too. But query and answer must compare as identical!
  47
  48    This precludes doing anything smart with EDNS directly from the packet */
  49 class RecursorPacketCache
  50 {
  51 public:
  52   RecursorPacketCache();
  53   bool getResponsePacket(unsigned int tag, const std::string& queryPacket, time_t now, std::string* responsePacket, uint32_t* age);
  54   void insertResponsePacket(unsigned int tag, const DNSName& qname, uint16_t qtype, const std::string& queryPacket, const std::string& responsePacket, time_t now, uint32_t ttd);
  55   bool getResponsePacket(unsigned int tag, const std::string& queryPacket, time_t now, std::string* responsePacket, uint32_t* age, RecProtoBufMessage* protobufMessage);
  56   void insertResponsePacket(unsigned int tag, const DNSName& qname, uint16_t qtype, const std::string& queryPacket, const std::string& responsePacket, time_t now, uint32_t ttd, const RecProtoBufMessage* protobufMessage);
  57   void doPruneTo(unsigned int maxSize=250000);
  58   uint64_t doDump(int fd);
  59   int doWipePacketCache(const DNSName& name, uint16_t qtype=0xffff, bool subtree=false);
  60
  61   void prune();
  62   uint64_t d_hits, d_misses;
  63   uint64_t size();
  64   uint64_t bytes();
  65
  66 private:
  67   struct HashTag {};
  68   struct NameTag {};
  69   struct Entry
  70   {
  71     mutable uint32_t d_ttd;
  72     mutable uint32_t d_creation; // so we can 'age' our packets
  73     DNSName d_name;
  74     uint16_t d_type;
  75     mutable std::string d_packet; // "I know what I am doing"
  76 #ifdef HAVE_PROTOBUF
  77     mutable RecProtoBufMessage d_protobufMessage;
  78 #endif
  79     uint32_t d_qhash;
  80     uint32_t d_tag;
  81     inline bool operator<(const struct Entry& rhs) const;
  82
  83     uint32_t getTTD() const
  84     {
  85       return d_ttd;
  86     }
  87   };
  88   uint32_t canHashPacket(const std::string& origPacket);
  89   typedef multi_index_container<
  90     Entry,
  91     indexed_by  <
  92       hashed_non_unique<tag<HashTag>, composite_key<Entry, member<Entry,uint32_t,&Entry::d_tag>, member<Entry,uint32_t,&Entry::d_qhash> > >,
  93       sequenced<> ,
  94       ordered_non_unique<tag<NameTag>, member<Entry,DNSName,&Entry::d_name>, CanonDNSNameCompare >
  95       >
  96   > packetCache_t;
  97
  98   packetCache_t d_packetCache;
  99 };
 100
 101 #endif