remoting/protocol/session_manager.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // The purpose of SessionManager is to facilitate creation of chromotocol
   6 // sessions. Both host and client use it to establish chromotocol
   7 // sessions. JingleChromotocolServer implements this inteface using
   8 // libjingle.
   9 //
  10 // OUTGOING SESSIONS
  11 // Connect() must be used to create new session to a remote host. The
  12 // returned session is initially in INITIALIZING state. Later state is
  13 // changed to CONNECTED if the session is accepted by the host or
  14 // CLOSED if the session is rejected.
  15 //
  16 // INCOMING SESSIONS
  17 // The IncomingSessionCallback is called when a client attempts to connect.
  18 // The callback function decides whether the session should be accepted or
  19 // rejected.
  20 //
  21 // AUTHENTICATION
  22 // Implementations of the Session and SessionManager interfaces
  23 // delegate authentication to an Authenticator implementation. For
  24 // incoming connections authenticators are created using an
  25 // AuthenticatorFactory set via the set_authenticator_factory()
  26 // method. For outgoing sessions authenticator must be passed to the
  27 // Connect() method. The Session's state changes to AUTHENTICATED once
  28 // authentication succeeds.
  29 //
  30 // SESSION OWNERSHIP AND SHUTDOWN
  31 // The SessionManager must not be closed or destroyed before all sessions
  32 // created by that SessionManager are destroyed. Caller owns Sessions
  33 // created by a SessionManager (except rejected
  34 // sessions). The SignalStrategy must outlive the SessionManager.
  35 //
  36 // PROTOCOL VERSION NEGOTIATION
  37 // When client connects to a host it sends a session-initiate stanza with list
  38 // of supported configurations for each channel. If the host decides to accept
  39 // session, then it selects configuration that is supported by both sides
  40 // and then replies with the session-accept stanza that contans selected
  41 // configuration. The configuration specified in the session-accept is used
  42 // for the session.
  43 //
  44 // The CandidateSessionConfig class represents list of configurations
  45 // supported by an endpoint. The |candidate_config| argument in the Connect()
  46 // specifies configuration supported on the client side. When the host receives
  47 // session-initiate stanza, the IncomingSessionCallback is called. The
  48 // configuration sent in the session-intiate staza is available via
  49 // ChromotocolConnnection::candidate_config(). If an incoming session is
  50 // being accepted then the IncomingSessionCallback callback function must
  51 // select session configuration and then set it with Session::set_config().
  52
  53 #ifndef REMOTING_PROTOCOL_SESSION_MANAGER_H_
  54 #define REMOTING_PROTOCOL_SESSION_MANAGER_H_
  55
  56 #include <string>
  57
  58 #include "base/callback.h"
  59 #include "base/memory/ref_counted.h"
  60 #include "base/threading/non_thread_safe.h"
  61 #include "remoting/protocol/session.h"
  62
  63 namespace remoting {
  64
  65 class SignalStrategy;
  66
  67 namespace protocol {
  68
  69 class Authenticator;
  70 class AuthenticatorFactory;
  71
  72 // Generic interface for Chromoting session manager.
  73 //
  74 // TODO(sergeyu): Split this into two separate interfaces: one for the
  75 // client side and one for the host side.
  76 class SessionManager : public base::NonThreadSafe {
  77  public:
  78   SessionManager() {}
  79   virtual ~SessionManager() {}
  80
  81   enum IncomingSessionResponse {
  82     // Accept the session.
  83     ACCEPT,
  84
  85     // Reject the session due to incompatible session configuration.
  86     INCOMPATIBLE,
  87
  88     // Reject the session because the host is currently disabled due
  89     // to previous login attempts.
  90     OVERLOAD,
  91
  92     // Reject the session because the client is not allowed to connect
  93     // to the host.
  94     DECLINE,
  95   };
  96
  97   class Listener {
  98    public:
  99     Listener() {}
 100
 101     // Called when the session manager is ready to create outgoing
 102     // sessions. May be called from Init() or after Init()
 103     // returns.
 104     virtual void OnSessionManagerReady() = 0;
 105
 106     // Called when a new session is received. If the host decides to
 107     // accept the session it should set the |response| to
 108     // ACCEPT. Otherwise it should set it to DECLINE, or
 109     // INCOMPATIBLE. INCOMPATIBLE indicates that the session has
 110     // incompatible configuration, and cannot be accepted. If the
 111     // callback accepts the |session| then it must also set
 112     // configuration for the |session| using Session::set_config().
 113     // The callback must take ownership of the |session| if it ACCEPTs it.
 114     virtual void OnIncomingSession(Session* session,
 115                                    IncomingSessionResponse* response) = 0;
 116
 117    protected:
 118     ~Listener() {}
 119   };
 120
 121   // Initializes the session client. Caller retains ownership of the
 122   // |signal_strategy| and |listener|.
 123   virtual void Init(SignalStrategy* signal_strategy,
 124                     Listener* listener) = 0;
 125
 126   // Tries to create a session to the host |jid|. Must be called only
 127   // after initialization has finished successfully, i.e. after
 128   // Listener::OnInitialized() has been called.
 129   //
 130   // |host_jid| is the full jid of the host to connect to.
 131   // |authenticator| is a client authenticator for the session.
 132   // |config| contains the session configurations that the client supports.
 133   virtual scoped_ptr<Session> Connect(
 134       const std::string& host_jid,
 135       scoped_ptr<Authenticator> authenticator,
 136       scoped_ptr<CandidateSessionConfig> config) = 0;
 137
 138   // Close session manager. Can be called only after all corresponding
 139   // sessions are destroyed. No callbacks are called after this method
 140   // returns.
 141   virtual void Close() = 0;
 142
 143   // Set authenticator factory that should be used to authenticate
 144   // incoming connection. No connections will be accepted if
 145   // authenticator factory isn't set. Must not be called more than
 146   // once per SessionManager because it may not be safe to delete
 147   // factory before all authenticators it created are deleted.
 148   virtual void set_authenticator_factory(
 149       scoped_ptr<AuthenticatorFactory> authenticator_factory) = 0;
 150
 151  private:
 152   DISALLOW_COPY_AND_ASSIGN(SessionManager);
 153 };
 154
 155 }  // namespace protocol
 156 }  // namespace remoting
 157
 158 #endif  // REMOTING_PROTOCOL_SESSION_MANAGER_H_