1/*
2 * libjingle
3 * Copyright 2012 Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 *  1. Redistributions of source code must retain the above copyright notice,
9 *     this list of conditions and the following disclaimer.
10 *  2. Redistributions in binary form must reproduce the above copyright notice,
11 *     this list of conditions and the following disclaimer in the documentation
12 *     and/or other materials provided with the distribution.
13 *  3. The name of the author may not be used to endorse or promote products
14 *     derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#ifndef TALK_APP_WEBRTC_DATACHANNEL_H_
29#define TALK_APP_WEBRTC_DATACHANNEL_H_
30
31#include <deque>
32#include <set>
33#include <string>
34
35#include "talk/app/webrtc/datachannelinterface.h"
36#include "talk/app/webrtc/proxy.h"
37#include "talk/media/base/mediachannel.h"
38#include "talk/session/media/channel.h"
39#include "webrtc/base/messagehandler.h"
40#include "webrtc/base/scoped_ref_ptr.h"
41#include "webrtc/base/sigslot.h"
42
43namespace webrtc {
44
45class DataChannel;
46
47class DataChannelProviderInterface {
48 public:
49  // Sends the data to the transport.
50  virtual bool SendData(const cricket::SendDataParams& params,
51                        const rtc::Buffer& payload,
52                        cricket::SendDataResult* result) = 0;
53  // Connects to the transport signals.
54  virtual bool ConnectDataChannel(DataChannel* data_channel) = 0;
55  // Disconnects from the transport signals.
56  virtual void DisconnectDataChannel(DataChannel* data_channel) = 0;
57  // Adds the data channel SID to the transport for SCTP.
58  virtual void AddSctpDataStream(int sid) = 0;
59  // Removes the data channel SID from the transport for SCTP.
60  virtual void RemoveSctpDataStream(int sid) = 0;
61  // Returns true if the transport channel is ready to send data.
62  virtual bool ReadyToSendData() const = 0;
63
64 protected:
65  virtual ~DataChannelProviderInterface() {}
66};
67
68struct InternalDataChannelInit : public DataChannelInit {
69  enum OpenHandshakeRole {
70    kOpener,
71    kAcker,
72    kNone
73  };
74  // The default role is kOpener because the default |negotiated| is false.
75  InternalDataChannelInit() : open_handshake_role(kOpener) {}
76  explicit InternalDataChannelInit(const DataChannelInit& base)
77      : DataChannelInit(base), open_handshake_role(kOpener) {
78    // If the channel is externally negotiated, do not send the OPEN message.
79    if (base.negotiated) {
80      open_handshake_role = kNone;
81    }
82  }
83
84  OpenHandshakeRole open_handshake_role;
85};
86
87// Helper class to allocate unique IDs for SCTP DataChannels
88class SctpSidAllocator {
89 public:
90  // Gets the first unused odd/even id based on the DTLS role. If |role| is
91  // SSL_CLIENT, the allocated id starts from 0 and takes even numbers;
92  // otherwise, the id starts from 1 and takes odd numbers.
93  // Returns false if no id can be allocated.
94  bool AllocateSid(rtc::SSLRole role, int* sid);
95
96  // Attempts to reserve a specific sid. Returns false if it's unavailable.
97  bool ReserveSid(int sid);
98
99  // Indicates that |sid| isn't in use any more, and is thus available again.
100  void ReleaseSid(int sid);
101
102 private:
103  // Checks if |sid| is available to be assigned to a new SCTP data channel.
104  bool IsSidAvailable(int sid) const;
105
106  std::set<int> used_sids_;
107};
108
109// DataChannel is a an implementation of the DataChannelInterface based on
110// libjingle's data engine. It provides an implementation of unreliable or
111// reliabledata channels. Currently this class is specifically designed to use
112// both RtpDataEngine and SctpDataEngine.
113
114// DataChannel states:
115// kConnecting: The channel has been created the transport might not yet be
116//              ready.
117// kOpen: The channel have a local SSRC set by a call to UpdateSendSsrc
118//        and a remote SSRC set by call to UpdateReceiveSsrc and the transport
119//        has been writable once.
120// kClosing: DataChannelInterface::Close has been called or UpdateReceiveSsrc
121//           has been called with SSRC==0
122// kClosed: Both UpdateReceiveSsrc and UpdateSendSsrc has been called with
123//          SSRC==0.
124class DataChannel : public DataChannelInterface,
125                    public sigslot::has_slots<>,
126                    public rtc::MessageHandler {
127 public:
128  static rtc::scoped_refptr<DataChannel> Create(
129      DataChannelProviderInterface* provider,
130      cricket::DataChannelType dct,
131      const std::string& label,
132      const InternalDataChannelInit& config);
133
134  virtual void RegisterObserver(DataChannelObserver* observer);
135  virtual void UnregisterObserver();
136
137  virtual std::string label() const { return label_; }
138  virtual bool reliable() const;
139  virtual bool ordered() const { return config_.ordered; }
140  virtual uint16_t maxRetransmitTime() const {
141    return config_.maxRetransmitTime;
142  }
143  virtual uint16_t maxRetransmits() const { return config_.maxRetransmits; }
144  virtual std::string protocol() const { return config_.protocol; }
145  virtual bool negotiated() const { return config_.negotiated; }
146  virtual int id() const { return config_.id; }
147  virtual uint64_t buffered_amount() const;
148  virtual void Close();
149  virtual DataState state() const { return state_; }
150  virtual bool Send(const DataBuffer& buffer);
151
152  // rtc::MessageHandler override.
153  virtual void OnMessage(rtc::Message* msg);
154
155  // Called when the channel's ready to use.  That can happen when the
156  // underlying DataMediaChannel becomes ready, or when this channel is a new
157  // stream on an existing DataMediaChannel, and we've finished negotiation.
158  void OnChannelReady(bool writable);
159
160  // Sigslots from cricket::DataChannel
161  void OnDataReceived(cricket::DataChannel* channel,
162                      const cricket::ReceiveDataParams& params,
163                      const rtc::Buffer& payload);
164  void OnStreamClosedRemotely(uint32_t sid);
165
166  // The remote peer request that this channel should be closed.
167  void RemotePeerRequestClose();
168
169  // The following methods are for SCTP only.
170
171  // Sets the SCTP sid and adds to transport layer if not set yet. Should only
172  // be called once.
173  void SetSctpSid(int sid);
174  // Called when the transport channel is created.
175  // Only needs to be called for SCTP data channels.
176  void OnTransportChannelCreated();
177  // Called when the transport channel is destroyed.
178  void OnTransportChannelDestroyed();
179
180  // The following methods are for RTP only.
181
182  // Set the SSRC this channel should use to send data on the
183  // underlying data engine. |send_ssrc| == 0 means that the channel is no
184  // longer part of the session negotiation.
185  void SetSendSsrc(uint32_t send_ssrc);
186  // Set the SSRC this channel should use to receive data from the
187  // underlying data engine.
188  void SetReceiveSsrc(uint32_t receive_ssrc);
189
190  cricket::DataChannelType data_channel_type() const {
191    return data_channel_type_;
192  }
193
194  // Emitted when state transitions to kClosed.
195  // In the case of SCTP channels, this signal can be used to tell when the
196  // channel's sid is free.
197  sigslot::signal1<DataChannel*> SignalClosed;
198
199 protected:
200  DataChannel(DataChannelProviderInterface* client,
201              cricket::DataChannelType dct,
202              const std::string& label);
203  virtual ~DataChannel();
204
205 private:
206  // A packet queue which tracks the total queued bytes. Queued packets are
207  // owned by this class.
208  class PacketQueue {
209   public:
210    PacketQueue();
211    ~PacketQueue();
212
213    size_t byte_count() const {
214      return byte_count_;
215    }
216
217    bool Empty() const;
218
219    DataBuffer* Front();
220
221    void Pop();
222
223    void Push(DataBuffer* packet);
224
225    void Clear();
226
227    void Swap(PacketQueue* other);
228
229   private:
230    std::deque<DataBuffer*> packets_;
231    size_t byte_count_;
232  };
233
234  // The OPEN(_ACK) signaling state.
235  enum HandshakeState {
236    kHandshakeInit,
237    kHandshakeShouldSendOpen,
238    kHandshakeShouldSendAck,
239    kHandshakeWaitingForAck,
240    kHandshakeReady
241  };
242
243  bool Init(const InternalDataChannelInit& config);
244  void DoClose();
245  void UpdateState();
246  void SetState(DataState state);
247  void DisconnectFromProvider();
248
249  void DeliverQueuedReceivedData();
250
251  void SendQueuedDataMessages();
252  bool SendDataMessage(const DataBuffer& buffer, bool queue_if_blocked);
253  bool QueueSendDataMessage(const DataBuffer& buffer);
254
255  void SendQueuedControlMessages();
256  void QueueControlMessage(const rtc::Buffer& buffer);
257  bool SendControlMessage(const rtc::Buffer& buffer);
258
259  std::string label_;
260  InternalDataChannelInit config_;
261  DataChannelObserver* observer_;
262  DataState state_;
263  cricket::DataChannelType data_channel_type_;
264  DataChannelProviderInterface* provider_;
265  HandshakeState handshake_state_;
266  bool connected_to_provider_;
267  bool send_ssrc_set_;
268  bool receive_ssrc_set_;
269  bool writable_;
270  uint32_t send_ssrc_;
271  uint32_t receive_ssrc_;
272  // Control messages that always have to get sent out before any queued
273  // data.
274  PacketQueue queued_control_data_;
275  PacketQueue queued_received_data_;
276  PacketQueue queued_send_data_;
277};
278
279// Define proxy for DataChannelInterface.
280BEGIN_PROXY_MAP(DataChannel)
281  PROXY_METHOD1(void, RegisterObserver, DataChannelObserver*)
282  PROXY_METHOD0(void, UnregisterObserver)
283  PROXY_CONSTMETHOD0(std::string, label)
284  PROXY_CONSTMETHOD0(bool, reliable)
285  PROXY_CONSTMETHOD0(bool, ordered)
286  PROXY_CONSTMETHOD0(uint16_t, maxRetransmitTime)
287  PROXY_CONSTMETHOD0(uint16_t, maxRetransmits)
288  PROXY_CONSTMETHOD0(std::string, protocol)
289  PROXY_CONSTMETHOD0(bool, negotiated)
290  PROXY_CONSTMETHOD0(int, id)
291  PROXY_CONSTMETHOD0(DataState, state)
292  PROXY_CONSTMETHOD0(uint64_t, buffered_amount)
293  PROXY_METHOD0(void, Close)
294  PROXY_METHOD1(bool, Send, const DataBuffer&)
295END_PROXY()
296
297}  // namespace webrtc
298
299#endif  // TALK_APP_WEBRTC_DATACHANNEL_H_
300