Limits only 16 new QUIC connections can be opened per epoll event.

net/tools/quic/quic_dispatcher.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // A server side dispatcher which dispatches a given client's data to their
 // stream.
 
 #ifndef NET_TOOLS_QUIC_QUIC_DISPATCHER_H_
 #define NET_TOOLS_QUIC_QUIC_DISPATCHER_H_
 
@@ skipping 128 matching lines @@
   bool OnWindowUpdateFrame(const QuicWindowUpdateFrame& frame) override;
   bool OnBlockedFrame(const QuicBlockedFrame& frame) override;
   bool OnPathCloseFrame(const QuicPathCloseFrame& frame) override;
   void OnPacketComplete() override;
 
   // QuicBufferedPacketStore::VisitorInterface implementation.
   void OnExpiredPackets(QuicConnectionId connection_id,
                         QuicBufferedPacketStore::BufferedPacketList
                             early_arrived_packets) override;
 
+  // Create connections for previously buffered CHLOs as many as allowed.
+  virtual void ProcessBufferedChlos(size_t max_connections_to_create);
+
+  // Return true if there is CHLO buffered.
+  virtual bool HasChlosBuffered() const;
+
  protected:
   virtual QuicServerSessionBase* CreateQuicSession(
       QuicConnectionId connection_id,
       const IPEndPoint& client_address) = 0;
 
   // Called when a connection is rejected statelessly.
   virtual void OnConnectionRejectedStatelessly();
 
   // Called when a connection is closed statelessly.
   virtual void OnConnectionClosedStatelessly(QuicErrorCode error);
@@ skipping 111 matching lines @@
   // Returns a fate which describes what subsequent processing should be
   // performed on the packets, like ValidityChecks.
   QuicPacketFate MaybeRejectStatelessly(QuicConnectionId connection_id,
                                         const QuicPacketHeader& header);
 
   // Deliver |packets| to |session| for further processing.
   void DeliverPacketsToSession(
       const std::list<QuicBufferedPacketStore::BufferedPacket>& packets,
       QuicServerSessionBase* session);
 
+  void set_new_sessions_allowed_per_event_loop(
+      int16_t new_sessions_allowed_per_event_loop) {
+    new_sessions_allowed_per_event_loop_ = new_sessions_allowed_per_event_loop;
+  }
+
   const QuicConfig& config_;
 
   const QuicCryptoServerConfig* crypto_config_;
 
   // The cache for most recently compressed certs.
   QuicCompressedCertsCache compressed_certs_cache_;
 
   // The list of connections waiting to write.
   WriteBlockedList write_blocked_list_;
 
@@ skipping 32 matching lines @@
 
   // Used to get the supported versions based on flag. Does not own.
   QuicVersionManager* version_manager_;
 
   QuicFramer framer_;
 
   // The last error set by SetLastError(), which is called by
   // framer_visitor_->OnError().
   QuicErrorCode last_error_;
 
+  // A backward counter of how many new sessions can be create within current
+  // event loop. When reaches 0, it means can't create sessions for now.
+  int16_t new_sessions_allowed_per_event_loop_;
+
   DISALLOW_COPY_AND_ASSIGN(QuicDispatcher);
 };
 
 }  // namespace net
 
 #endif  // NET_TOOLS_QUIC_QUIC_DISPATCHER_H_