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/*
* libjingle
* Copyright 2004 Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "talk/session/media/rtcpmuxfilter.h"
#include "webrtc/base/logging.h"
namespace cricket {
RtcpMuxFilter::RtcpMuxFilter() : state_(ST_INIT), offer_enable_(false) {
}
bool RtcpMuxFilter::IsActive() const {
return state_ == ST_SENTPRANSWER ||
state_ == ST_RECEIVEDPRANSWER ||
state_ == ST_ACTIVE;
}
void RtcpMuxFilter::SetActive() {
state_ = ST_ACTIVE;
}
bool RtcpMuxFilter::SetOffer(bool offer_enable, ContentSource src) {
if (state_ == ST_ACTIVE) {
// Fail if we try to deactivate and no-op if we try and activate.
return offer_enable;
}
if (!ExpectOffer(offer_enable, src)) {
LOG(LS_ERROR) << "Invalid state for change of RTCP mux offer";
return false;
}
offer_enable_ = offer_enable;
state_ = (src == CS_LOCAL) ? ST_SENTOFFER : ST_RECEIVEDOFFER;
return true;
}
bool RtcpMuxFilter::SetProvisionalAnswer(bool answer_enable,
ContentSource src) {
if (state_ == ST_ACTIVE) {
// Fail if we try to deactivate and no-op if we try and activate.
return answer_enable;
}
if (!ExpectAnswer(src)) {
LOG(LS_ERROR) << "Invalid state for RTCP mux provisional answer";
return false;
}
if (offer_enable_) {
if (answer_enable) {
if (src == CS_REMOTE)
state_ = ST_RECEIVEDPRANSWER;
else // CS_LOCAL
state_ = ST_SENTPRANSWER;
} else {
// The provisional answer doesn't want to use RTCP mux.
// Go back to the original state after the offer was set and wait for next
// provisional or final answer.
if (src == CS_REMOTE)
state_ = ST_SENTOFFER;
else // CS_LOCAL
state_ = ST_RECEIVEDOFFER;
}
} else if (answer_enable) {
// If the offer didn't specify RTCP mux, the answer shouldn't either.
LOG(LS_WARNING) << "Invalid parameters in RTCP mux provisional answer";
return false;
}
return true;
}
bool RtcpMuxFilter::SetAnswer(bool answer_enable, ContentSource src) {
if (state_ == ST_ACTIVE) {
// Fail if we try to deactivate and no-op if we try and activate.
return answer_enable;
}
if (!ExpectAnswer(src)) {
LOG(LS_ERROR) << "Invalid state for RTCP mux answer";
return false;
}
if (offer_enable_ && answer_enable) {
state_ = ST_ACTIVE;
} else if (answer_enable) {
// If the offer didn't specify RTCP mux, the answer shouldn't either.
LOG(LS_WARNING) << "Invalid parameters in RTCP mux answer";
return false;
} else {
state_ = ST_INIT;
}
return true;
}
// Check the RTP payload type. If 63 < payload type < 96, it's RTCP.
// For additional details, see http://tools.ietf.org/html/rfc5761.
bool IsRtcp(const char* data, int len) {
if (len < 2) {
return false;
}
char pt = data[1] & 0x7F;
return (63 < pt) && (pt < 96);
}
bool RtcpMuxFilter::DemuxRtcp(const char* data, int len) {
// If we're muxing RTP/RTCP, we must inspect each packet delivered
// and determine whether it is RTP or RTCP. We do so by looking at
// the RTP payload type (see IsRtcp). Note that if we offer RTCP
// mux, we may receive muxed RTCP before we receive the answer, so
// we operate in that state too.
bool offered_mux = ((state_ == ST_SENTOFFER) && offer_enable_);
return (IsActive() || offered_mux) && IsRtcp(data, len);
}
bool RtcpMuxFilter::ExpectOffer(bool offer_enable, ContentSource source) {
return ((state_ == ST_INIT) ||
(state_ == ST_ACTIVE && offer_enable == offer_enable_) ||
(state_ == ST_SENTOFFER && source == CS_LOCAL) ||
(state_ == ST_RECEIVEDOFFER && source == CS_REMOTE));
}
bool RtcpMuxFilter::ExpectAnswer(ContentSource source) {
return ((state_ == ST_SENTOFFER && source == CS_REMOTE) ||
(state_ == ST_RECEIVEDOFFER && source == CS_LOCAL) ||
(state_ == ST_SENTPRANSWER && source == CS_LOCAL) ||
(state_ == ST_RECEIVEDPRANSWER && source == CS_REMOTE));
}
} // namespace cricket
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