1 files changed, 125 insertions, 0 deletions
diff --git a/third_party/libwebrtc/pc/rtcp_mux_filter.cc b/third_party/libwebrtc/pc/rtcp_mux_filter.cc
new file mode 100644
index 0000000000..62adea2243
--- /dev/null
+++ b/third_party/libwebrtc/pc/rtcp_mux_filter.cc
@@ -0,0 +1,125 @@
+/*
+ *  Copyright 2004 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "pc/rtcp_mux_filter.h"
+
+#include "rtc_base/logging.h"
+
+namespace cricket {
+
+RtcpMuxFilter::RtcpMuxFilter() : state_(ST_INIT), offer_enable_(false) {}
+
+bool RtcpMuxFilter::IsFullyActive() const {
+  return state_ == ST_ACTIVE;
+}
+
+bool RtcpMuxFilter::IsProvisionallyActive() const {
+  return state_ == ST_SENTPRANSWER || state_ == ST_RECEIVEDPRANSWER;
+}
+
+bool RtcpMuxFilter::IsActive() const {
+  return IsFullyActive() || IsProvisionallyActive();
+}
+
+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)) {
+    RTC_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)) {
+    RTC_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.
+    RTC_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)) {
+    RTC_LOG(LS_ERROR) << "Invalid state for RTCP mux answer, state is "
+                      << state_ << ", source is " << src;
+    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.
+    RTC_LOG(LS_WARNING) << "Invalid parameters in RTCP mux answer";
+    return false;
+  } else {
+    state_ = ST_INIT;
+  }
+  return true;
+}
+
+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