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 #include "talk/session/media/rtcpmuxfilter.h"
29
30 #include "webrtc/base/logging.h"
31
32 namespace cricket {
33
RtcpMuxFilter()34 RtcpMuxFilter::RtcpMuxFilter() : state_(ST_INIT), offer_enable_(false) {
35 }
36
IsActive() const37 bool RtcpMuxFilter::IsActive() const {
38 return state_ == ST_SENTPRANSWER ||
39 state_ == ST_RECEIVEDPRANSWER ||
40 state_ == ST_ACTIVE;
41 }
42
SetActive()43 void RtcpMuxFilter::SetActive() {
44 state_ = ST_ACTIVE;
45 }
46
SetOffer(bool offer_enable,ContentSource src)47 bool RtcpMuxFilter::SetOffer(bool offer_enable, ContentSource src) {
48 if (state_ == ST_ACTIVE) {
49 // Fail if we try to deactivate and no-op if we try and activate.
50 return offer_enable;
51 }
52
53 if (!ExpectOffer(offer_enable, src)) {
54 LOG(LS_ERROR) << "Invalid state for change of RTCP mux offer";
55 return false;
56 }
57
58 offer_enable_ = offer_enable;
59 state_ = (src == CS_LOCAL) ? ST_SENTOFFER : ST_RECEIVEDOFFER;
60 return true;
61 }
62
SetProvisionalAnswer(bool answer_enable,ContentSource src)63 bool RtcpMuxFilter::SetProvisionalAnswer(bool answer_enable,
64 ContentSource src) {
65 if (state_ == ST_ACTIVE) {
66 // Fail if we try to deactivate and no-op if we try and activate.
67 return answer_enable;
68 }
69
70 if (!ExpectAnswer(src)) {
71 LOG(LS_ERROR) << "Invalid state for RTCP mux provisional answer";
72 return false;
73 }
74
75 if (offer_enable_) {
76 if (answer_enable) {
77 if (src == CS_REMOTE)
78 state_ = ST_RECEIVEDPRANSWER;
79 else // CS_LOCAL
80 state_ = ST_SENTPRANSWER;
81 } else {
82 // The provisional answer doesn't want to use RTCP mux.
83 // Go back to the original state after the offer was set and wait for next
84 // provisional or final answer.
85 if (src == CS_REMOTE)
86 state_ = ST_SENTOFFER;
87 else // CS_LOCAL
88 state_ = ST_RECEIVEDOFFER;
89 }
90 } else if (answer_enable) {
91 // If the offer didn't specify RTCP mux, the answer shouldn't either.
92 LOG(LS_WARNING) << "Invalid parameters in RTCP mux provisional answer";
93 return false;
94 }
95
96 return true;
97 }
98
SetAnswer(bool answer_enable,ContentSource src)99 bool RtcpMuxFilter::SetAnswer(bool answer_enable, ContentSource src) {
100 if (state_ == ST_ACTIVE) {
101 // Fail if we try to deactivate and no-op if we try and activate.
102 return answer_enable;
103 }
104
105 if (!ExpectAnswer(src)) {
106 LOG(LS_ERROR) << "Invalid state for RTCP mux answer";
107 return false;
108 }
109
110 if (offer_enable_ && answer_enable) {
111 state_ = ST_ACTIVE;
112 } else if (answer_enable) {
113 // If the offer didn't specify RTCP mux, the answer shouldn't either.
114 LOG(LS_WARNING) << "Invalid parameters in RTCP mux answer";
115 return false;
116 } else {
117 state_ = ST_INIT;
118 }
119 return true;
120 }
121
122 // Check the RTP payload type. If 63 < payload type < 96, it's RTCP.
123 // For additional details, see http://tools.ietf.org/html/rfc5761.
IsRtcp(const char * data,int len)124 bool IsRtcp(const char* data, int len) {
125 if (len < 2) {
126 return false;
127 }
128 char pt = data[1] & 0x7F;
129 return (63 < pt) && (pt < 96);
130 }
131
DemuxRtcp(const char * data,int len)132 bool RtcpMuxFilter::DemuxRtcp(const char* data, int len) {
133 // If we're muxing RTP/RTCP, we must inspect each packet delivered
134 // and determine whether it is RTP or RTCP. We do so by looking at
135 // the RTP payload type (see IsRtcp). Note that if we offer RTCP
136 // mux, we may receive muxed RTCP before we receive the answer, so
137 // we operate in that state too.
138 bool offered_mux = ((state_ == ST_SENTOFFER) && offer_enable_);
139 return (IsActive() || offered_mux) && IsRtcp(data, len);
140 }
141
ExpectOffer(bool offer_enable,ContentSource source)142 bool RtcpMuxFilter::ExpectOffer(bool offer_enable, ContentSource source) {
143 return ((state_ == ST_INIT) ||
144 (state_ == ST_ACTIVE && offer_enable == offer_enable_) ||
145 (state_ == ST_SENTOFFER && source == CS_LOCAL) ||
146 (state_ == ST_RECEIVEDOFFER && source == CS_REMOTE));
147 }
148
ExpectAnswer(ContentSource source)149 bool RtcpMuxFilter::ExpectAnswer(ContentSource source) {
150 return ((state_ == ST_SENTOFFER && source == CS_REMOTE) ||
151 (state_ == ST_RECEIVEDOFFER && source == CS_LOCAL) ||
152 (state_ == ST_SENTPRANSWER && source == CS_LOCAL) ||
153 (state_ == ST_RECEIVEDPRANSWER && source == CS_REMOTE));
154 }
155
156 } // namespace cricket
157