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      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 
     43 namespace webrtc {
     44 
     45 class DataChannel;
     46 
     47 class 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 
     68 struct 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
     88 class 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.
    124 class 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.
    280 BEGIN_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&)
    295 END_PROXY()
    296 
    297 }  // namespace webrtc
    298 
    299 #endif  // TALK_APP_WEBRTC_DATACHANNEL_H_
    300