pdns/dnsdist-cache.hh

   1 #pragma once
   2
   3 #include <atomic>
   4 #include <unordered_map>
   5 #include "lock.hh"
   6
   7 struct DNSQuestion;
   8
   9 class DNSDistPacketCache : boost::noncopyable
  10 {
  11 public:
  12   DNSDistPacketCache(size_t maxEntries, uint32_t maxTTL=86400, uint32_t minTTL=0, uint32_t servFailTTL=60, uint32_t staleTTL=60);
  13   ~DNSDistPacketCache();
  14
  15   void insert(uint32_t key, const DNSName& qname, uint16_t qtype, uint16_t qclass, const char* response, uint16_t responseLen, bool tcp, bool servFail=false);
  16   bool get(const DNSQuestion& dq, uint16_t consumed, uint16_t queryId, char* response, uint16_t* responseLen, uint32_t* keyOut, uint32_t allowExpired=0, bool skipAging=false);
  17   void purgeExpired(size_t upTo=0);
  18   void expunge(size_t upTo=0);
  19   void expungeByName(const DNSName& name, uint16_t qtype=QType::ANY);
  20   bool isFull();
  21   string toString();
  22   uint64_t getSize() const { return d_map.size(); }
  23   uint64_t getHits() const { return d_hits; }
  24   uint64_t getMisses() const { return d_misses; }
  25   uint64_t getDeferredLookups() const { return d_deferredLookups; }
  26   uint64_t getDeferredInserts() const { return d_deferredInserts; }
  27   uint64_t getLookupCollisions() const { return d_lookupCollisions; }
  28   uint64_t getInsertCollisions() const { return d_insertCollisions; }
  29   uint64_t getMaxEntries() const { return d_maxEntries; }
  30   uint64_t getTTLTooShorts() const { return d_ttlTooShorts; }
  31   uint64_t getEntriesCount();
  32
  33   static uint32_t getMinTTL(const char* packet, uint16_t length);
  34
  35 private:
  36
  37   struct CacheValue
  38   {
  39     time_t getTTD() const { return validity; }
  40     std::string value;
  41     DNSName qname;
  42     uint16_t qtype{0};
  43     uint16_t qclass{0};
  44     time_t added{0};
  45     time_t validity{0};
  46     uint16_t len{0};
  47     bool tcp{false};
  48   };
  49
  50   static uint32_t getKey(const DNSName& qname, uint16_t consumed, const unsigned char* packet, uint16_t packetLen, bool tcp);
  51   static bool cachedValueMatches(const CacheValue& cachedValue, const DNSName& qname, uint16_t qtype, uint16_t qclass, bool tcp);
  52
  53   pthread_rwlock_t d_lock;
  54   std::unordered_map<uint32_t,CacheValue> d_map;
  55   std::atomic<uint64_t> d_deferredLookups{0};
  56   std::atomic<uint64_t> d_deferredInserts{0};
  57   std::atomic<uint64_t> d_hits{0};
  58   std::atomic<uint64_t> d_misses{0};
  59   std::atomic<uint64_t> d_insertCollisions{0};
  60   std::atomic<uint64_t> d_lookupCollisions{0};
  61   std::atomic<uint64_t> d_ttlTooShorts{0};
  62   size_t d_maxEntries;
  63   uint32_t d_maxTTL;
  64   uint32_t d_servFailTTL;
  65   uint32_t d_minTTL;
  66   uint32_t d_staleTTL;
  67 };