1 files changed, 145 insertions, 0 deletions
diff --git a/dnsdist-cache.hh b/dnsdist-cache.hh
new file mode 100644
index 0000000..3309459
--- /dev/null
+++ b/dnsdist-cache.hh
@@ -0,0 +1,145 @@
+/*
+ * This file is part of PowerDNS or dnsdist.
+ * Copyright -- PowerDNS.COM B.V. and its contributors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * In addition, for the avoidance of any doubt, permission is granted to
+ * link this program with OpenSSL and to (re)distribute the binaries
+ * produced as the result of such linking.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#pragma once
+
+#include <atomic>
+#include <unordered_map>
+
+#include "iputils.hh"
+#include "lock.hh"
+#include "noinitvector.hh"
+#include "stat_t.hh"
+#include "ednsoptions.hh"
+
+struct DNSQuestion;
+
+class DNSDistPacketCache : boost::noncopyable
+{
+public:
+  DNSDistPacketCache(size_t maxEntries, uint32_t maxTTL=86400, uint32_t minTTL=0, uint32_t tempFailureTTL=60, uint32_t maxNegativeTTL=3600, uint32_t staleTTL=60, bool dontAge=false, uint32_t shards=1, bool deferrableInsertLock=true, bool parseECS=false);
+
+  void insert(uint32_t key, const boost::optional<Netmask>& subnet, uint16_t queryFlags, bool dnssecOK, const DNSName& qname, uint16_t qtype, uint16_t qclass, const PacketBuffer& response, bool receivedOverUDP, uint8_t rcode, boost::optional<uint32_t> tempFailureTTL);
+  bool get(DNSQuestion& dq, uint16_t queryId, uint32_t* keyOut, boost::optional<Netmask>& subnet, bool dnssecOK, bool receivedOverUDP, uint32_t allowExpired = 0, bool skipAging = false);
+  size_t purgeExpired(size_t upTo, const time_t now);
+  size_t expunge(size_t upTo=0);
+  size_t expungeByName(const DNSName& name, uint16_t qtype=QType::ANY, bool suffixMatch=false);
+  bool isFull();
+  string toString();
+  uint64_t getSize();
+  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; }
+  uint64_t getMaxEntries() const { return d_maxEntries; }
+  uint64_t getTTLTooShorts() const { return d_ttlTooShorts; }
+  uint64_t getEntriesCount();
+  uint64_t dump(int fd);
+  void setSkippedOptions(const std::unordered_set<uint16_t>& optionsToSkip);
+
+  bool isECSParsingEnabled() const { return d_parseECS; }
+
+  bool keepStaleData() const
+  {
+    return d_keepStaleData;
+  }
+  void setKeepStaleData(bool keep)
+  {
+    d_keepStaleData = keep;
+  }
+
+
+  void setECSParsingEnabled(bool enabled)
+  {
+    d_parseECS = enabled;
+  }
+
+  uint32_t getKey(const DNSName::string_t& qname, size_t qnameWireLength, const PacketBuffer& packet, bool receivedOverUDP);
+
+  static uint32_t getMinTTL(const char* packet, uint16_t length, bool* seenNoDataSOA);
+  static bool getClientSubnet(const PacketBuffer& packet, size_t qnameWireLength, boost::optional<Netmask>& subnet);
+
+private:
+
+  struct CacheValue
+  {
+    time_t getTTD() const { return validity; }
+    std::string value;
+    DNSName qname;
+    boost::optional<Netmask> subnet;
+    uint16_t qtype{0};
+    uint16_t qclass{0};
+    uint16_t queryFlags{0};
+    time_t added{0};
+    time_t validity{0};
+    uint16_t len{0};
+    bool receivedOverUDP{false};
+    bool dnssecOK{false};
+  };
+
+  class CacheShard
+  {
+  public:
+    CacheShard()
+    {
+    }
+    CacheShard(const CacheShard& old)
+    {
+    }
+
+    void setSize(size_t maxSize)
+    {
+      d_map.write_lock()->reserve(maxSize);
+    }
+
+    SharedLockGuarded<std::unordered_map<uint32_t,CacheValue>> d_map;
+    std::atomic<uint64_t> d_entriesCount{0};
+  };
+
+  bool cachedValueMatches(const CacheValue& cachedValue, uint16_t queryFlags, const DNSName& qname, uint16_t qtype, uint16_t qclass, bool receivedOverUDP, bool dnssecOK, const boost::optional<Netmask>& subnet) const;
+  uint32_t getShardIndex(uint32_t key) const;
+  void insertLocked(CacheShard& shard, std::unordered_map<uint32_t,CacheValue>& map, uint32_t key, CacheValue& newValue);
+
+  std::vector<CacheShard> d_shards;
+  std::unordered_set<uint16_t> d_optionsToSkip{EDNSOptionCode::COOKIE};
+
+  pdns::stat_t d_deferredLookups{0};
+  pdns::stat_t d_deferredInserts{0};
+  pdns::stat_t d_hits{0};
+  pdns::stat_t d_misses{0};
+  pdns::stat_t d_insertCollisions{0};
+  pdns::stat_t d_lookupCollisions{0};
+  pdns::stat_t d_ttlTooShorts{0};
+
+  size_t d_maxEntries;
+  uint32_t d_shardCount;
+  uint32_t d_maxTTL;
+  uint32_t d_tempFailureTTL;
+  uint32_t d_maxNegativeTTL;
+  uint32_t d_minTTL;
+  uint32_t d_staleTTL;
+  bool d_dontAge;
+  bool d_deferrableInsertLock;
+  bool d_parseECS;
+  bool d_keepStaleData{false};
+};