1 /*
2  * libjingle
3  * Copyright 2011, 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 // This file contains a class used for creating and parsing ROAP messages
29 // as defined in http://tools.ietf.org/html/draft-jennings-rtcweb-signaling-01.
30 // The RoapSession is responsible for keeping track of ROAP specific
31 // attributes such as offerSessionId etc of a single session but not the logic
32 // for when to create a specific message.
33 
34 #ifndef TALK_APP_WEBRTC_ROAPSESSION_H_
35 #define TALK_APP_WEBRTC_ROAPSESSION_H_
36 
37 #include <string>
38 #include <vector>
39 
40 #include "talk/app/webrtc/roaperrorcodes.h"
41 #include "talk/base/basictypes.h"
42 
43 namespace webrtc {
44 
45 class RoapAnswer;
46 class RoapError;
47 class RoapMessageBase;
48 class RoapOffer;
49 
50 class RoapSession {
51  public:
52   // ParseResult is the result of parsing a message.
53   // It can be either an identified message type or a detected error.
54   enum ParseResult {
55     kOffer,
56     kAnswerMoreComing,  // More coming flag set. The SDP contains candidates.
57     kAnswer,
58     kOk,
59     kShutDown,
60     kError,
61     // The messages below are errors that can occur during parsing.
62     kParseConflict,  // Conflict detected during parsing of offer.
63     kParseDoubleConflict,  // Double conflict detected during parsing of offer.
64     kInvalidMessage  // The parsed message is invalid.
65   };
66 
67   RoapSession();
68 
69   // Creates a ROAP offer message based on the provided session description
70   // including candidates. This will update states in the ROAP sessions
71   // variables such as sequence number and create a local session id.
72   std::string CreateOffer(const std::string& desc);
73 
74   // Creates a ROAP answer message based on the provided session description.
75   // An offer must have been parsed before this function can be called.
76   std::string CreateAnswer(const std::string& desc);
77   std::string CreateOk();
78   std::string CreateShutDown();
79   std::string CreateErrorMessage(RoapErrorCode error);
80   ParseResult Parse(const std::string& msg);
81   RoapErrorCode RemoteError();
82 
RemoteDescription()83   const std::string& RemoteDescription() { return remote_desc_; }
84 
85  private:
86   ParseResult ValidateOffer(RoapOffer* received_offer);
87   ParseResult ValidateAnswer(RoapAnswer* received_answer);
88   ParseResult ValidateOk(const RoapMessageBase& message);
89   ParseResult ValidateError(const RoapError& message);
90 
91   uint32 seq_;  // Sequence number of current message exchange.
92   std::string local_id_;  // offererSessionId / answerSessionId of local peer.
93   std::string remote_id_;  // offererSessionId / answerSessionId of remote peer.
94   uint32 local_tie_breaker_;  // tieBreaker of last sent offer.
95   bool waiting_for_answer_;
96 
97   std::string received_offer_id_;  // offererSessionId in last received message.
98   std::string received_answer_id_;  // answerSessionId in last received message.
99   uint32 received_seq_;  // Sequence number of last received message.
100   std::string session_token_;
101   std::string response_token_;
102 
103   std::string remote_desc_;
104   RoapErrorCode remote_error_;
105 };
106 
107 }  // namespace webrtc
108 
109 #endif  // TALK_APP_WEBRTC_ROAPSESSION_H_
110