// 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.

#ifndef NET_HTTP_HTTP_NETWORK_SESSION_H_
#define NET_HTTP_HTTP_NETWORK_SESSION_H_

#include <stddef.h>
#include <stdint.h>

#include <map>
#include <memory>
#include <set>
#include <string>
#include <unordered_set>
#include <vector>

#include "base/bind.h"
#include "base/containers/flat_set.h"
#include "base/memory/memory_coordinator_client.h"
#include "base/memory/memory_pressure_monitor.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/threading/thread_checker.h"
#include "net/base/host_mapping_rules.h"
#include "net/base/host_port_pair.h"
#include "net/base/net_export.h"
#include "net/dns/host_resolver.h"
#include "net/http/http_auth_cache.h"
#include "net/http/http_stream_factory.h"
#include "net/quic/chromium/quic_stream_factory.h"
#include "net/socket/next_proto.h"
#include "net/spdy/spdy_session_pool.h"
#include "net/ssl/ssl_client_auth_cache.h"
#include "net/third_party/spdy/core/spdy_protocol.h"

namespace base {
class Value;
namespace trace_event {
class ProcessMemoryDump;
}
}

namespace net {

class CTPolicyEnforcer;
class CertVerifier;
class ChannelIDService;
class ClientSocketFactory;
class ClientSocketPoolManager;
class CTVerifier;
class HostResolver;
class HttpAuthHandlerFactory;
class HttpNetworkSessionPeer;
class HttpProxyClientSocketPool;
class HttpResponseBodyDrainer;
class HttpServerProperties;
class NetLog;
class NetworkQualityProvider;
class ProxyDelegate;
class ProxyResolutionService;
class QuicClock;
class QuicCryptoClientStreamFactory;
class SocketPerformanceWatcherFactory;
class SOCKSClientSocketPool;
class SSLClientSocketPool;
class SSLConfigService;
class TransportClientSocketPool;
class TransportSecurityState;
class WebSocketEndpointLockManager;

// Specifies the maximum HPACK dynamic table size the server is allowed to set.
const uint32_t kSpdyMaxHeaderTableSize = 64 * 1024;

// Specifies the maximum concurrent streams server could send (via push).
const uint32_t kSpdyMaxConcurrentPushedStreams = 1000;

// This class holds session objects used by HttpNetworkTransaction objects.
class NET_EXPORT HttpNetworkSession : public base::MemoryCoordinatorClient {
 public:
  // Self-contained structure with all the simple configuration options
  // supported by the HttpNetworkSession.
  struct NET_EXPORT Params {
    Params();
    Params(const Params& other);
    ~Params();

    enum class TcpFastOpenMode {
      DISABLED,
      // If true, TCP fast open will be used for all HTTPS connections.
      ENABLED_FOR_SSL_ONLY,
      // TCP fast open will be used for all HTTP/HTTPS connections.
      // TODO(mmenke): With 0-RTT session resumption, does this option make
      // sense?
      ENABLED_FOR_ALL,
    };

    bool enable_server_push_cancellation;
    HostMappingRules host_mapping_rules;
    bool ignore_certificate_errors;
    uint16_t testing_fixed_http_port;
    uint16_t testing_fixed_https_port;
    TcpFastOpenMode tcp_fast_open_mode;
    bool enable_user_alternate_protocol_ports;

    // Use SPDY ping frames to test for connection health after idle.
    bool enable_spdy_ping_based_connection_checking;
    bool enable_http2;
    size_t spdy_session_max_recv_window_size;
    // HTTP/2 connection settings.
    // Unknown settings will still be sent to the server.
    spdy::SettingsMap http2_settings;
    // Source of time for SPDY connections.
    SpdySessionPool::TimeFunc time_func;
    // Whether to enable HTTP/2 Alt-Svc entries.
    bool enable_http2_alternative_service;
    // Whether to enable Websocket over HTTP/2.
    bool enable_websocket_over_http2;

    // Enables QUIC support.
    bool enable_quic;

    // QUIC runtime configuration options.

    // Versions of QUIC which may be used.
    QuicTransportVersionVector quic_supported_versions;
    // User agent description to send in the QUIC handshake.
    std::string quic_user_agent_id;
    // Limit on the size of QUIC packets.
    size_t quic_max_packet_length;
    // Maximum number of server configs that are to be stored in
    // HttpServerProperties, instead of the disk cache.
    size_t quic_max_server_configs_stored_in_properties;
    // QUIC will be used for all connections in this set.
    std::set<HostPortPair> origins_to_force_quic_on;
    // Set of QUIC tags to send in the handshake's connection options.
    QuicTagVector quic_connection_options;
    // Set of QUIC tags to send in the handshake's connection options that only
    // affect the client.
    QuicTagVector quic_client_connection_options;
    // Enables experimental optimization for receiving data in UDPSocket.
    bool quic_enable_socket_recv_optimization;

    // Active QUIC experiments

    // Marks a QUIC server broken when a connection blackholes after the
    // handshake is confirmed.
    bool mark_quic_broken_when_network_blackholes;
    // Retry requests which fail with QUIC_PROTOCOL_ERROR, and mark QUIC
    // broken if the retry succeeds.
    bool retry_without_alt_svc_on_quic_errors;
    // If true, alt-svc headers advertising QUIC in IETF format will be
    // supported.
    bool support_ietf_format_quic_altsvc;
    // If true, all QUIC sessions are closed when any local IP address changes.
    bool quic_close_sessions_on_ip_change;
    // Specifies QUIC idle connection state lifetime.
    int quic_idle_connection_timeout_seconds;
    // Specifies the reduced ping timeout subsequent connections should use when
    // a connection was timed out with open streams.
    int quic_reduced_ping_timeout_seconds;
    // Maximum time the session can be alive before crypto handshake is
    // finished.
    int quic_max_time_before_crypto_handshake_seconds;
    // Maximum idle time before the crypto handshake has completed.
    int quic_max_idle_time_before_crypto_handshake_seconds;
    // If true, active QUIC sessions may be migrated onto a new network when
    // the platform indicates that the default network is changing.
    bool quic_migrate_sessions_on_network_change;
    // If true, active QUIC sessions experiencing poor connectivity may be
    // migrated onto a new network.
    bool quic_migrate_sessions_early;
    // If true, connection migration v2 will be used to migrate existing
    // sessions to network when the platform indicates that the default network
    // is changing.
    bool quic_migrate_sessions_on_network_change_v2;
    // If true, connection migration v2 may be used to migrate active QUIC
    // sessions to alternative network if current network connectivity is poor.
    bool quic_migrate_sessions_early_v2;
    // Maximum time the session could be on the non-default network before
    // migrates back to default network. Defaults to
    // kMaxTimeOnNonDefaultNetwork.
    base::TimeDelta quic_max_time_on_non_default_network;
    // Maximum number of migrations to the non-default network on path
    // degrading per network for each session.
    int quic_max_migrations_to_non_default_network_on_path_degrading;
    // If true, allows migration of QUIC connections to a server-specified
    // alternate server address.
    bool quic_allow_server_migration;
    // If true, allows QUIC to use alternative services with a different
    // hostname from the origin.
    bool quic_allow_remote_alt_svc;
    // If true, bidirectional streams over QUIC will be disabled.
    bool quic_disable_bidirectional_streams;
    // If true, enable force HOL blocking.  For measurement purposes.
    bool quic_force_hol_blocking;
    // If true, race cert verification with host resolution.
    bool quic_race_cert_verification;
    // If true, estimate the initial RTT for QUIC connections based on network.
    bool quic_estimate_initial_rtt;
    // If true, client headers will include HTTP/2 stream dependency info
    // derived from the request priority.
    bool quic_headers_include_h2_stream_dependency;
    // If non-empty, QUIC will only be spoken to hosts in this list.
    base::flat_set<std::string> quic_host_whitelist;

    // Enable support for Token Binding.
    bool enable_token_binding;
    // Enable Channel ID. Channel ID is being deprecated.
    bool enable_channel_id;

    // Enable HTTP/0.9 for HTTP/HTTPS on ports other than the default one for
    // each protocol.
    bool http_09_on_non_default_ports_enabled;

    // If true, idle sockets won't be closed when memory pressure happens.
    bool disable_idle_sockets_close_on_memory_pressure;
  };

  // Structure with pointers to the dependencies of the HttpNetworkSession.
  // These objects must all outlive the HttpNetworkSession.
  struct NET_EXPORT Context {
    Context();
    Context(const Context& other);
    ~Context();

    ClientSocketFactory* client_socket_factory;
    HostResolver* host_resolver;
    CertVerifier* cert_verifier;
    ChannelIDService* channel_id_service;
    TransportSecurityState* transport_security_state;
    CTVerifier* cert_transparency_verifier;
    CTPolicyEnforcer* ct_policy_enforcer;
    ProxyResolutionService* proxy_resolution_service;
    SSLConfigService* ssl_config_service;
    HttpAuthHandlerFactory* http_auth_handler_factory;
    HttpServerProperties* http_server_properties;
    NetLog* net_log;
    SocketPerformanceWatcherFactory* socket_performance_watcher_factory;
    NetworkQualityProvider* network_quality_provider;

    // Source of time for QUIC connections.
    QuicClock* quic_clock;
    // Source of entropy for QUIC connections.
    QuicRandom* quic_random;
    // Optional factory to use for creating QuicCryptoClientStreams.
    QuicCryptoClientStreamFactory* quic_crypto_client_stream_factory;

    ProxyDelegate* proxy_delegate;
  };

  enum SocketPoolType {
    NORMAL_SOCKET_POOL,
    WEBSOCKET_SOCKET_POOL,
    NUM_SOCKET_POOL_TYPES
  };

  HttpNetworkSession(const Params& params, const Context& context);
  ~HttpNetworkSession() override;

  HttpAuthCache* http_auth_cache() { return &http_auth_cache_; }
  SSLClientAuthCache* ssl_client_auth_cache() {
    return &ssl_client_auth_cache_;
  }

  void AddResponseDrainer(std::unique_ptr<HttpResponseBodyDrainer> drainer);

  // Removes the drainer from the session. Does not dispose of it.
  void RemoveResponseDrainer(HttpResponseBodyDrainer* drainer);

  TransportClientSocketPool* GetTransportSocketPool(SocketPoolType pool_type);
  SSLClientSocketPool* GetSSLSocketPool(SocketPoolType pool_type);
  SOCKSClientSocketPool* GetSocketPoolForSOCKSProxy(
      SocketPoolType pool_type,
      const HostPortPair& socks_proxy);
  HttpProxyClientSocketPool* GetSocketPoolForHTTPProxy(
      SocketPoolType pool_type,
      const HostPortPair& http_proxy);
  SSLClientSocketPool* GetSocketPoolForSSLWithProxy(
      SocketPoolType pool_type,
      const HostPortPair& proxy_server);

  CertVerifier* cert_verifier() { return cert_verifier_; }
  ProxyResolutionService* proxy_resolution_service() {
      return proxy_resolution_service_;
  }
  SSLConfigService* ssl_config_service() { return ssl_config_service_.get(); }
  WebSocketEndpointLockManager* websocket_endpoint_lock_manager() {
    return websocket_endpoint_lock_manager_.get();
  }
  SpdySessionPool* spdy_session_pool() { return &spdy_session_pool_; }
  QuicStreamFactory* quic_stream_factory() { return &quic_stream_factory_; }
  HttpAuthHandlerFactory* http_auth_handler_factory() {
    return http_auth_handler_factory_;
  }
  HttpServerProperties* http_server_properties() {
    return http_server_properties_;
  }
  HttpStreamFactory* http_stream_factory() {
    return http_stream_factory_.get();
  }
  NetLog* net_log() {
    return net_log_;
  }

  // Creates a Value summary of the state of the socket pools.
  std::unique_ptr<base::Value> SocketPoolInfoToValue() const;

  // Creates a Value summary of the state of the SPDY sessions.
  std::unique_ptr<base::Value> SpdySessionPoolInfoToValue() const;

  // Creates a Value summary of the state of the QUIC sessions and
  // configuration.
  std::unique_ptr<base::Value> QuicInfoToValue() const;

  void CloseAllConnections();
  void CloseIdleConnections();

  // Returns the original Params used to construct this session.
  const Params& params() const { return params_; }
  // Returns the original Context used to construct this session.
  const Context& context() const { return context_; }

  bool IsProtocolEnabled(NextProto protocol) const;

  void SetServerPushDelegate(std::unique_ptr<ServerPushDelegate> push_delegate);

  // Populates |*alpn_protos| with protocols to be used with ALPN.
  void GetAlpnProtos(NextProtoVector* alpn_protos) const;

  // Populates |server_config| and |proxy_config| based on this session and
  // |request|.
  void GetSSLConfig(const HttpRequestInfo& request,
                    SSLConfig* server_config,
                    SSLConfig* proxy_config) const;

  // Dumps memory allocation stats. |parent_dump_absolute_name| is the name
  // used by the parent MemoryAllocatorDump in the memory dump hierarchy.
  void DumpMemoryStats(base::trace_event::ProcessMemoryDump* pmd,
                       const std::string& parent_absolute_name) const;

  // Evaluates if QUIC is enabled for new streams.
  bool IsQuicEnabled() const;

  // Disable QUIC for new streams.
  void DisableQuic();

 private:
  friend class HttpNetworkSessionPeer;

  ClientSocketPoolManager* GetSocketPoolManager(SocketPoolType pool_type);

  // Flush sockets on low memory notifications callback.
  void OnMemoryPressure(
      base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level);

  // base::MemoryCoordinatorClient implementation:
  void OnPurgeMemory() override;

  NetLog* const net_log_;
  HttpServerProperties* const http_server_properties_;
  CertVerifier* const cert_verifier_;
  HttpAuthHandlerFactory* const http_auth_handler_factory_;

  ProxyResolutionService* const proxy_resolution_service_;
  const scoped_refptr<SSLConfigService> ssl_config_service_;

  HttpAuthCache http_auth_cache_;
  SSLClientAuthCache ssl_client_auth_cache_;
  std::unique_ptr<WebSocketEndpointLockManager>
      websocket_endpoint_lock_manager_;
  std::unique_ptr<ClientSocketPoolManager> normal_socket_pool_manager_;
  std::unique_ptr<ClientSocketPoolManager> websocket_socket_pool_manager_;
  std::unique_ptr<ServerPushDelegate> push_delegate_;
  QuicStreamFactory quic_stream_factory_;
  SpdySessionPool spdy_session_pool_;
  std::unique_ptr<HttpStreamFactory> http_stream_factory_;
  std::map<HttpResponseBodyDrainer*, std::unique_ptr<HttpResponseBodyDrainer>>
      response_drainers_;
  NextProtoVector next_protos_;

  Params params_;
  Context context_;

  std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;

  THREAD_CHECKER(thread_checker_);
};

}  // namespace net

#endif  // NET_HTTP_HTTP_NETWORK_SESSION_H_