1 files changed, 98 insertions, 0 deletions
diff --git a/dnsdist-async.hh b/dnsdist-async.hh
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--- /dev/null
+++ b/dnsdist-async.hh
@@ -0,0 +1,98 @@
+/*
+ * 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 <thread>
+
+#include <boost/multi_index_container.hpp>
+#include <boost/multi_index/ordered_index.hpp>
+#include <boost/multi_index/key_extractors.hpp>
+
+#include "dnsdist-tcp.hh"
+
+namespace dnsdist
+{
+class AsynchronousHolder
+{
+public:
+  AsynchronousHolder(bool failOpen = true);
+  ~AsynchronousHolder();
+  void push(uint16_t asyncID, uint16_t queryID, const struct timeval& ttd, std::unique_ptr<CrossProtocolQuery>&& query);
+  std::unique_ptr<CrossProtocolQuery> get(uint16_t asyncID, uint16_t queryID);
+  bool empty();
+  void stop();
+
+private:
+  struct TTDTag
+  {
+  };
+  struct IDTag
+  {
+  };
+
+  struct Entry
+  {
+    /* not used by any of the indexes, so mutable */
+    mutable std::unique_ptr<CrossProtocolQuery> d_query;
+    struct timeval d_ttd;
+    uint16_t d_asyncID;
+    uint16_t d_queryID;
+  };
+
+  typedef multi_index_container<
+    Entry,
+    indexed_by<
+      ordered_unique<tag<IDTag>,
+                     composite_key<
+                       Entry,
+                       member<Entry, uint16_t, &Entry::d_queryID>,
+                       member<Entry, uint16_t, &Entry::d_asyncID>>>,
+      ordered_non_unique<tag<TTDTag>,
+                         member<Entry, struct timeval, &Entry::d_ttd>>>>
+    content_t;
+
+  static void pickupExpired(content_t&, const struct timeval& now, std::list<std::pair<uint16_t, std::unique_ptr<CrossProtocolQuery>>>& expiredEvents);
+  static struct timeval getNextTTD(const content_t&);
+
+  struct Data
+  {
+    LockGuarded<content_t> d_content;
+    FDWrapper d_notifyPipe;
+    FDWrapper d_watchPipe;
+    bool d_failOpen{true};
+    bool d_done{false};
+  };
+  std::shared_ptr<Data> d_data{nullptr};
+
+  static void mainThread(std::shared_ptr<Data> data);
+  static bool wait(const Data& data, FDMultiplexer& mplexer, std::vector<int>& readyFDs, int atMostMs);
+  bool notify() const;
+};
+
+bool suspendQuery(DNSQuestion& dq, uint16_t asyncID, uint16_t queryID, uint32_t timeoutMs);
+bool suspendResponse(DNSResponse& dr, uint16_t asyncID, uint16_t queryID, uint32_t timeoutMs);
+bool queueQueryResumptionEvent(std::unique_ptr<CrossProtocolQuery>&& query);
+bool resumeQuery(std::unique_ptr<CrossProtocolQuery>&& query);
+void handleQueuedAsynchronousEvents();
+
+extern std::unique_ptr<AsynchronousHolder> g_asyncHolder;
+}