Merge pull request #3404 from pieterlexis/sles12

[thirdparty/pdns.git] / pdns / dnsdist-cache.hh

#pragma once

#include <atomic>
#include <unordered_map>
#include "lock.hh"

class DNSDistPacketCache : boost::noncopyable
{
public:
  DNSDistPacketCache(size_t maxEntries, uint32_t maxTTL=86400, uint32_t minTTL=60);
  ~DNSDistPacketCache();

  void insert(uint32_t key, const DNSName& qname, uint16_t qtype, uint16_t qclass, const char* response, uint16_t responseLen);
  bool get(const unsigned char* query, uint16_t queryLen, const DNSName& qname, uint16_t qtype, uint16_t qclass, uint16_t consumed, uint16_t queryId, char* response, uint16_t* responseLen, uint32_t* keyOut, bool skipAging=false);
  void purge(size_t upTo=0);
  void expunge(const DNSName& name, uint16_t qtype=QType::ANY);
  bool isFull();
  string toString();
  uint64_t getSize() const { return d_map.size(); };
  uint64_t getHits() const { return d_hits; };
  uint64_t getMisses() const { return d_misses; };
  uint64_t getDeferredLookups() const { return d_deferredLookups; };
  uint64_t getDeferredInserts() const { return d_deferredInserts; };
  uint64_t getLookupCollisions() const { return d_lookupCollisions; };
  uint64_t getInsertCollisions() const { return d_insertCollisions; };

  static uint32_t getMinTTL(const char* packet, uint16_t length);

private:

  struct CacheValue
  {
    time_t getTTD() const { return validity; }
    std::string value;
    DNSName qname;
    uint16_t qtype{0};
    uint16_t qclass{0};
    time_t added{0};
    time_t validity{0};
    uint16_t len{0};
  };

  static uint32_t getKey(const DNSName& qname, uint16_t consumed, const unsigned char* packet, uint16_t packetLen);
  static bool cachedValueMatches(const CacheValue& cachedValue, const DNSName& qname, uint16_t qtype, uint16_t qclass);

  pthread_rwlock_t d_lock;
  std::unordered_map<uint32_t,CacheValue> d_map;
  std::atomic<uint64_t> d_deferredLookups{0};
  std::atomic<uint64_t> d_deferredInserts{0};
  std::atomic<uint64_t> d_hits{0};
  std::atomic<uint64_t> d_misses{0};
  std::atomic<uint64_t> d_insertCollisions{0};
  std::atomic<uint64_t> d_lookupCollisions{0};
  size_t d_maxEntries;
  uint32_t d_maxTTL;
  uint32_t d_minTTL;
};