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      1 /*
      2  * libjingle
      3  * Copyright 2004 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_SESSION_MEDIA_RTCPMUXFILTER_H_
     29 #define TALK_SESSION_MEDIA_RTCPMUXFILTER_H_
     30 
     31 #include "webrtc/p2p/base/sessiondescription.h"
     32 #include "webrtc/base/basictypes.h"
     33 
     34 namespace cricket {
     35 
     36 // RTCP Muxer, as defined in RFC 5761 (http://tools.ietf.org/html/rfc5761)
     37 class RtcpMuxFilter {
     38  public:
     39   RtcpMuxFilter();
     40 
     41   // Whether the filter is active, i.e. has RTCP mux been properly negotiated.
     42   bool IsActive() const;
     43 
     44   // Make the filter active, regardless of the current state.
     45   void SetActive();
     46 
     47   // Specifies whether the offer indicates the use of RTCP mux.
     48   bool SetOffer(bool offer_enable, ContentSource src);
     49 
     50   // Specifies whether the provisional answer indicates the use of RTCP mux.
     51   bool SetProvisionalAnswer(bool answer_enable, ContentSource src);
     52 
     53   // Specifies whether the answer indicates the use of RTCP mux.
     54   bool SetAnswer(bool answer_enable, ContentSource src);
     55 
     56   // Determines whether the specified packet is RTCP.
     57   bool DemuxRtcp(const char* data, int len);
     58 
     59  private:
     60   bool ExpectOffer(bool offer_enable, ContentSource source);
     61   bool ExpectAnswer(ContentSource source);
     62   enum State {
     63     // RTCP mux filter unused.
     64     ST_INIT,
     65     // Offer with RTCP mux enabled received.
     66     // RTCP mux filter is not active.
     67     ST_RECEIVEDOFFER,
     68     // Offer with RTCP mux enabled sent.
     69     // RTCP mux filter can demux incoming packets but is not active.
     70     ST_SENTOFFER,
     71     // RTCP mux filter is active but the sent answer is only provisional.
     72     // When the final answer is set, the state transitions to ST_ACTIVE or
     73     // ST_INIT.
     74     ST_SENTPRANSWER,
     75     // RTCP mux filter is active but the received answer is only provisional.
     76     // When the final answer is set, the state transitions to ST_ACTIVE or
     77     // ST_INIT.
     78     ST_RECEIVEDPRANSWER,
     79     // Offer and answer set, RTCP mux enabled. It is not possible to de-activate
     80     // the filter.
     81     ST_ACTIVE
     82   };
     83   State state_;
     84   bool offer_enable_;
     85 };
     86 
     87 }  // namespace cricket
     88 
     89 #endif  // TALK_SESSION_MEDIA_RTCPMUXFILTER_H_
     90