QUIC - disable QUIC under recent pathological connection errors.

net/quic/quic_client_session.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 client specific QuicSession subclass.  This class owns the underlying
 // QuicConnection and QuicConnectionHelper objects.  The connection stores
 // a non-owning pointer to the helper so this session needs to ensure that
 // the helper outlives the connection.
 
 #ifndef NET_QUIC_QUIC_CLIENT_SESSION_H_
@@ skipping 23 matching lines @@
 class QuicServerId;
 class QuicServerInfo;
 class QuicStreamFactory;
 class SSLInfo;
 class TransportSecurityState;
 
 namespace test {
 class QuicClientSessionPeer;
 }  // namespace test
 
+// Epitaphs will be used to track the most recent departed sessions,

[Ryan Hamilton, 2015/06/30 18:55:31]

Can you define "epitath" in this context?

[Buck, 2015/07/01 19:06:19]

I've dropped epitaph everywhere, and switched to DisabledReason.

+// to enable certain policies for when to disable QUIC, based on K
+// of N type thresholds.
+// Note: these values must be kept in sync with the corresponding values
+// of QuicDisabledReason in: tools/metrics/histograms/histograms.xml
+enum QuicClientSessionEpitaph {

[Ryan Hamilton, 2015/06/30 18:55:31]

nit: might as well nest this enum inside of QuicClientSession as
QuicClientSession::Epitath.

[Buck, 2015/07/01 19:06:19]

I've moved it (enum QuicDisabledReason) to quic_types.h, as it's referenced from
both QuicClientSession and QuicStreamFactory.

[Ryan Hamilton, 2015/07/06 18:25:41]

quic_types.h is part of the shared code. Since these enums are
chromium-specific, we should probably keep them in chromium-specific code. I
recommend QuicClientSession::DisabledReason or perhaps
QuicStreamFactory::DisabledReason?

[Buck, 2015/07/06 21:39:32]

Ok, QuicClientSession::DisabledReason it is.

+  QUIC_EPITAPH_RIP = 0,

[Ryan Hamilton, 2015/06/30 18:55:31]

What does "RIP" mean in this context? Perhaps add a comment?

[Buck, 2015/07/01 19:06:19]

Corresponding entry in QuicDisabledReason has a comment now.

+  QUIC_EPITAPH_PUBLIC_RESET_POST_HANDSHAKE = 1,
+  QUIC_EPITAPH_TIMEOUT_STREAMS_OPEN = 2,
+  QUIC_EPITAPH_MAX = 3,

[Ryan Hamilton, 2015/06/30 18:55:31]

Could the packet loss code take advantage of this, or does that live up in the
Factory, not down here in the Session?

[Buck, 2015/07/01 19:06:19]

Somewhat.  As per above, I've moved it and also added a
QUIC_DISABLED_BAD_PACKET_LOSS to the revised enum.

+};
+
 class NET_EXPORT_PRIVATE QuicClientSession : public QuicClientSessionBase,
                                              public QuicPacketReader::Visitor {
  public:
   // An interface for observing events on a session.
   class NET_EXPORT_PRIVATE Observer {
    public:
     virtual ~Observer() {}
     virtual void OnCryptoHandshakeConfirmed() = 0;
     virtual void OnSessionClosed(int error) = 0;
   };
@@ skipping 133 matching lines @@
   // than the number of round-trips needed for the handshake.
   int GetNumSentClientHellos() const;
 
   // Returns true if |hostname| may be pooled onto this session.  If this
   // is a secure QUIC session, then |hostname| must match the certificate
   // presented during the handshake.
   bool CanPool(const std::string& hostname, PrivacyMode privacy_mode) const;
 
   const QuicServerId& server_id() const { return server_id_; }
 
+  const QuicClientSessionEpitaph epitaph() const { return epitaph_; }
+
  protected:
   // QuicSession methods:
   QuicDataStream* CreateIncomingDynamicStream(QuicStreamId id) override;
 
  private:
   friend class test::QuicClientSessionPeer;
 
   typedef std::set<Observer*> ObserverSet;
   typedef std::list<StreamRequest*> StreamRequestQueue;
 
@@ skipping 47 matching lines @@
   size_t num_total_streams_;
   base::TaskRunner* task_runner_;
   BoundNetLog net_log_;
   QuicPacketReader packet_reader_;
   base::TimeTicks dns_resolution_end_time_;
   base::TimeTicks handshake_start_;  // Time the handshake was started.
   scoped_ptr<QuicConnectionLogger> logger_;
   // True when the session is going away, and streams may no longer be created
   // on this session. Existing stream will continue to be processed.
   bool going_away_;
+  QuicClientSessionEpitaph epitaph_;
   base::WeakPtrFactory<QuicClientSession> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicClientSession);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_CLIENT_SESSION_H_