pdns/packetcache.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 PACKETCACHE_HH
  23 #define PACKETCACHE_HH
  24
  25 #include <string>
  26 #include <utility>
  27 #include <map>
  28 #include <map>
  29 #include "dns.hh"
  30 #include <boost/version.hpp>
  31 #include "namespaces.hh"
  32 using namespace ::boost::multi_index;
  33
  34 #include "namespaces.hh"
  35 #include <boost/multi_index/hashed_index.hpp>
  36 #include "dnspacket.hh"
  37 #include "lock.hh"
  38 #include "statbag.hh"
  39
  40 /** This class performs 'whole packet caching'. Feed it a question packet and it will
  41     try to find an answer. If you have an answer, insert it to have it cached for later use.
  42     Take care not to replace existing cache entries. While this works, it is wasteful. Only
  43     insert packets that where not found by get()
  44
  45     Locking!
  46
  47     The cache itself is protected by a read/write lock. Because deleting is a two step process, which
  48     first marks and then sweeps, a second lock is present to prevent simultaneous inserts and deletes.
  49 */
  50
  51 class PacketCache : public boost::noncopyable
  52 {
  53 public:
  54   PacketCache();
  55   ~PacketCache();
  56   enum CacheEntryType { PACKETCACHE, QUERYCACHE};
  57
  58   void insert(DNSPacket *q, DNSPacket *r, bool recursive, unsigned int maxttl=UINT_MAX);  //!< We copy the contents of *p into our cache. Do not needlessly call this to insert questions already in the cache as it wastes resources
  59
  60   void insert(const DNSName &qname, const QType& qtype, CacheEntryType cet, const string& value, unsigned int ttl, int zoneID=-1, bool meritsRecursion=false,
  61     unsigned int maxReplyLen=512, bool dnssecOk=false, bool EDNS=false);
  62
  63   void insert(const DNSName &qname, const QType& qtype, CacheEntryType cet, const vector<DNSZoneRecord>& content, unsigned int ttl, int zoneID=-1);
  64
  65   int get(DNSPacket *p, DNSPacket *q, bool recursive); //!< We return a dynamically allocated copy out of our cache. You need to delete it. You also need to spoof in the right ID with the DNSPacket.spoofID() method.
  66   bool getEntry(const DNSName &qname, const QType& qtype, CacheEntryType cet, string& entry, int zoneID=-1,
  67     bool meritsRecursion=false, unsigned int maxReplyLen=512, bool dnssecOk=false, bool hasEDNS=false, unsigned int *age=0);
  68   bool getEntry(const DNSName &qname, const QType& qtype, CacheEntryType cet, vector<DNSZoneRecord>& entry, int zoneID=-1);
  69
  70
  71   int size() { return *d_statnumentries; } //!< number of entries in the cache
  72   void cleanupIfNeeded();
  73   void cleanup(); //!< force the cache to preen itself from expired packets
  74   int purge();
  75   int purge(const std::string& match); // could be $ terminated. Is not a dnsname!
  76   int purgeExact(const DNSName& qname); // no wildcard matching here
  77
  78   map<char,int> getCounts();
  79 private:
  80   bool getEntryLocked(const DNSName &content, const QType& qtype, CacheEntryType cet, string& entry, int zoneID=-1,
  81     bool meritsRecursion=false, unsigned int maxReplyLen=512, bool dnssecOk=false, bool hasEDNS=false, unsigned int *age=0);
  82   bool getEntryLocked(const DNSName &content, const QType& qtype, CacheEntryType cet, vector<DNSZoneRecord>& entry, int zoneID=-1);
  83
  84
  85   struct CacheEntry
  86   {
  87     CacheEntry() { qtype = ctype = 0; zoneID = -1; meritsRecursion=false; dnssecOk=false; hasEDNS=false; created=0; ttd=0; maxReplyLen=512;}
  88
  89     DNSName qname;
  90     string value;
  91     vector<DNSZoneRecord> drs;
  92     time_t created;
  93     time_t ttd;
  94
  95     uint16_t qtype;
  96     uint16_t ctype;
  97     int zoneID;
  98     unsigned int maxReplyLen;
  99
 100     bool meritsRecursion;
 101     bool dnssecOk;
 102     bool hasEDNS;
 103   };
 104
 105   void getTTLS();
 106
 107   struct UnorderedNameTag{};
 108   struct SequenceTag{};
 109   typedef multi_index_container<
 110     CacheEntry,
 111     indexed_by <
 112                 ordered_unique<
 113                       composite_key<
 114                         CacheEntry,
 115                         member<CacheEntry,DNSName,&CacheEntry::qname>,
 116                         member<CacheEntry,uint16_t,&CacheEntry::qtype>,
 117                         member<CacheEntry,uint16_t, &CacheEntry::ctype>,
 118                         member<CacheEntry,int, &CacheEntry::zoneID>,
 119                         member<CacheEntry,bool, &CacheEntry::meritsRecursion>,
 120                         member<CacheEntry,unsigned int, &CacheEntry::maxReplyLen>,
 121                         member<CacheEntry,bool, &CacheEntry::dnssecOk>,
 122                         member<CacheEntry,bool, &CacheEntry::hasEDNS>
 123                         >,
 124                        composite_key_compare<CanonDNSNameCompare, std::less<uint16_t>, std::less<uint16_t>, std::less<int>, std::less<bool>,
 125                           std::less<unsigned int>, std::less<bool>, std::less<bool> >
 126                        >,
 127       hashed_non_unique<tag<UnorderedNameTag>, composite_key<CacheEntry,
 128                                                              member<CacheEntry,DNSName,&CacheEntry::qname>,
 129                                                              member<CacheEntry,uint16_t,&CacheEntry::qtype>,
 130                                                              member<CacheEntry,uint16_t, &CacheEntry::ctype>,
 131                                                              member<CacheEntry,int, &CacheEntry::zoneID> > > ,
 132       sequenced<tag<SequenceTag>>
 133                            >
 134   > cmap_t;
 135
 136
 137   struct MapCombo
 138   {
 139     pthread_rwlock_t d_mut;
 140     cmap_t d_map;
 141   };
 142
 143   vector<MapCombo> d_maps;
 144   MapCombo& getMap(const DNSName& qname)
 145   {
 146     return d_maps[qname.hash() % d_maps.size()];
 147   }
 148
 149   AtomicCounter d_ops;
 150   time_t d_lastclean; // doesn't need to be atomic
 151   unsigned long d_nextclean;
 152   unsigned int d_cleaninterval;
 153   bool d_cleanskipped;
 154   AtomicCounter *d_statnumhit;
 155   AtomicCounter *d_statnummiss;
 156   AtomicCounter *d_statnumentries;
 157
 158   int d_ttl;
 159   int d_recursivettl;
 160   bool d_doRecursion;
 161
 162   static constexpr unsigned int s_mincleaninterval=1000, s_maxcleaninterval=300000;
 163 };
 164
 165
 166
 167 #endif /* PACKETCACHE_HH */