1/*
2 *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#ifndef WEBRTC_P2P_BASE_TRANSPORTCHANNEL_H_
12#define WEBRTC_P2P_BASE_TRANSPORTCHANNEL_H_
13
14#include <string>
15#include <vector>
16
17#include "webrtc/p2p/base/candidate.h"
18#include "webrtc/p2p/base/transport.h"
19#include "webrtc/p2p/base/transportdescription.h"
20#include "webrtc/base/asyncpacketsocket.h"
21#include "webrtc/base/basictypes.h"
22#include "webrtc/base/dscp.h"
23#include "webrtc/base/sigslot.h"
24#include "webrtc/base/socket.h"
25#include "webrtc/base/sslidentity.h"
26#include "webrtc/base/sslstreamadapter.h"
27
28namespace cricket {
29
30class Candidate;
31
32// Flags for SendPacket/SignalReadPacket.
33enum PacketFlags {
34  PF_NORMAL       = 0x00,  // A normal packet.
35  PF_SRTP_BYPASS  = 0x01,  // An encrypted SRTP packet; bypass any additional
36                           // crypto provided by the transport (e.g. DTLS)
37};
38
39// Used to indicate channel's connection state.
40enum TransportChannelState {
41  STATE_INIT,
42  STATE_CONNECTING,  // Will enter this state once a connection is created
43  STATE_COMPLETED,
44  STATE_FAILED
45};
46
47// A TransportChannel represents one logical stream of packets that are sent
48// between the two sides of a session.
49// TODO(deadbeef): This interface currently represents the unity of an ICE
50// transport and a DTLS transport. They need to be separated apart.
51class TransportChannel : public sigslot::has_slots<> {
52 public:
53  TransportChannel(const std::string& transport_name, int component)
54      : transport_name_(transport_name),
55        component_(component),
56        writable_(false),
57        receiving_(false) {}
58  virtual ~TransportChannel() {}
59
60  // TODO(guoweis) - Make this pure virtual once all subclasses of
61  // TransportChannel have this defined.
62  virtual TransportChannelState GetState() const {
63    return TransportChannelState::STATE_CONNECTING;
64  }
65
66  // TODO(mallinath) - Remove this API, as it's no longer useful.
67  // Returns the session id of this channel.
68  virtual const std::string SessionId() const { return std::string(); }
69
70  const std::string& transport_name() const { return transport_name_; }
71  int component() const { return component_; }
72
73  // Returns the states of this channel.  Each time one of these states changes,
74  // a signal is raised.  These states are aggregated by the TransportManager.
75  bool writable() const { return writable_; }
76  bool receiving() const { return receiving_; }
77  DtlsTransportState dtls_state() const { return dtls_state_; }
78  sigslot::signal1<TransportChannel*> SignalWritableState;
79  // Emitted when the TransportChannel's ability to send has changed.
80  sigslot::signal1<TransportChannel*> SignalReadyToSend;
81  sigslot::signal1<TransportChannel*> SignalReceivingState;
82  // Emitted whenever DTLS-SRTP is setup which will require setting up a new
83  // SRTP context.
84  sigslot::signal2<TransportChannel*, DtlsTransportState> SignalDtlsState;
85
86  // Attempts to send the given packet.  The return value is < 0 on failure.
87  // TODO: Remove the default argument once channel code is updated.
88  virtual int SendPacket(const char* data, size_t len,
89                         const rtc::PacketOptions& options,
90                         int flags = 0) = 0;
91
92  // Sets a socket option on this channel.  Note that not all options are
93  // supported by all transport types.
94  virtual int SetOption(rtc::Socket::Option opt, int value) = 0;
95  // TODO(pthatcher): Once Chrome's MockTransportChannel implments
96  // this, remove the default implementation.
97  virtual bool GetOption(rtc::Socket::Option opt, int* value) { return false; }
98
99  // Returns the most recent error that occurred on this channel.
100  virtual int GetError() = 0;
101
102  // Returns the current stats for this connection.
103  virtual bool GetStats(ConnectionInfos* infos) = 0;
104
105  // Is DTLS active?
106  virtual bool IsDtlsActive() const = 0;
107
108  // Default implementation.
109  virtual bool GetSslRole(rtc::SSLRole* role) const = 0;
110
111  // Sets up the ciphers to use for DTLS-SRTP. TODO(guoweis): Make this pure
112  // virtual once all dependencies have implementation.
113  virtual bool SetSrtpCryptoSuites(const std::vector<int>& ciphers);
114
115  // Keep the original one for backward compatibility until all dependencies
116  // move away. TODO(guoweis): Remove this function.
117  virtual bool SetSrtpCiphers(const std::vector<std::string>& ciphers);
118
119  // Finds out which DTLS-SRTP cipher was negotiated.
120  // TODO(guoweis): Remove this once all dependencies implement this.
121  virtual bool GetSrtpCryptoSuite(int* cipher) { return false; }
122
123  // Finds out which DTLS cipher was negotiated.
124  // TODO(guoweis): Remove this once all dependencies implement this.
125  virtual bool GetSslCipherSuite(int* cipher) { return false; }
126
127  // Gets the local RTCCertificate used for DTLS.
128  virtual rtc::scoped_refptr<rtc::RTCCertificate>
129  GetLocalCertificate() const = 0;
130
131  // Gets a copy of the remote side's SSL certificate, owned by the caller.
132  virtual bool GetRemoteSSLCertificate(rtc::SSLCertificate** cert) const = 0;
133
134  // Allows key material to be extracted for external encryption.
135  virtual bool ExportKeyingMaterial(const std::string& label,
136                                    const uint8_t* context,
137                                    size_t context_len,
138                                    bool use_context,
139                                    uint8_t* result,
140                                    size_t result_len) = 0;
141
142  // Signalled each time a packet is received on this channel.
143  sigslot::signal5<TransportChannel*, const char*,
144                   size_t, const rtc::PacketTime&, int> SignalReadPacket;
145
146  // Signalled each time a packet is sent on this channel.
147  sigslot::signal2<TransportChannel*, const rtc::SentPacket&> SignalSentPacket;
148
149  // This signal occurs when there is a change in the way that packets are
150  // being routed, i.e. to a different remote location. The candidate
151  // indicates where and how we are currently sending media.
152  sigslot::signal2<TransportChannel*, const Candidate&> SignalRouteChange;
153
154  // Invoked when the channel is being destroyed.
155  sigslot::signal1<TransportChannel*> SignalDestroyed;
156
157  // Debugging description of this transport channel.
158  std::string ToString() const;
159
160 protected:
161  // Sets the writable state, signaling if necessary.
162  void set_writable(bool writable);
163
164  // Sets the receiving state, signaling if necessary.
165  void set_receiving(bool receiving);
166
167  // Sets the DTLS state, signaling if necessary.
168  void set_dtls_state(DtlsTransportState state);
169
170 private:
171  // Used mostly for debugging.
172  std::string transport_name_;
173  int component_;
174  bool writable_;
175  bool receiving_;
176  DtlsTransportState dtls_state_ = DTLS_TRANSPORT_NEW;
177
178  RTC_DISALLOW_COPY_AND_ASSIGN(TransportChannel);
179};
180
181}  // namespace cricket
182
183#endif  // WEBRTC_P2P_BASE_TRANSPORTCHANNEL_H_
184