Refactor webrtc::PeerConnection to split out offer/answer
This reduces the size of peer_connection.cc by more than 2000 lines.
Design doc for refatoring (available on request):
https://docs.google.com/document/d/1ETeUhon9sJihEUpA9ZZHpOGhzDqlZGLQOk3cD_CjKDM/edit
Bug: webrtc:11995
Change-Id: I9ed8603807b45bb192a01df026755cb6b5365291
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/185801
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32212}
diff --git a/pc/sdp_offer_answer.cc b/pc/sdp_offer_answer.cc
new file mode 100644
index 0000000..51bb4ed
--- /dev/null
+++ b/pc/sdp_offer_answer.cc
@@ -0,0 +1,2928 @@
+/*
+ * Copyright 2020 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/sdp_offer_answer.h"
+
+#include "api/media_stream_proxy.h"
+#include "api/uma_metrics.h"
+#include "pc/media_stream.h"
+#include "pc/peer_connection.h"
+#include "pc/rtp_media_utils.h"
+#include "rtc_base/trace_event.h"
+#include "system_wrappers/include/metrics.h"
+
+using cricket::ContentInfo;
+using cricket::ContentInfos;
+using cricket::MediaContentDescription;
+using cricket::MediaProtocolType;
+using cricket::RidDescription;
+using cricket::RidDirection;
+using cricket::SessionDescription;
+using cricket::SimulcastDescription;
+using cricket::SimulcastLayer;
+using cricket::SimulcastLayerList;
+using cricket::StreamParams;
+using cricket::TransportInfo;
+
+using cricket::LOCAL_PORT_TYPE;
+using cricket::PRFLX_PORT_TYPE;
+using cricket::RELAY_PORT_TYPE;
+using cricket::STUN_PORT_TYPE;
+
+namespace webrtc {
+
+namespace {
+
+// Error messages
+const char kInvalidSdp[] = "Invalid session description.";
+const char kInvalidCandidates[] = "Description contains invalid candidates.";
+const char kBundleWithoutRtcpMux[] =
+ "rtcp-mux must be enabled when BUNDLE "
+ "is enabled.";
+const char kMlineMismatchInAnswer[] =
+ "The order of m-lines in answer doesn't match order in offer. Rejecting "
+ "answer.";
+const char kMlineMismatchInSubsequentOffer[] =
+ "The order of m-lines in subsequent offer doesn't match order from "
+ "previous offer/answer.";
+const char kSdpWithoutIceUfragPwd[] =
+ "Called with SDP without ice-ufrag and ice-pwd.";
+const char kSdpWithoutDtlsFingerprint[] =
+ "Called with SDP without DTLS fingerprint.";
+const char kSdpWithoutSdesCrypto[] = "Called with SDP without SDES crypto.";
+
+// UMA metric names.
+const char kSimulcastVersionApplyLocalDescription[] =
+ "WebRTC.PeerConnection.Simulcast.ApplyLocalDescription";
+const char kSimulcastVersionApplyRemoteDescription[] =
+ "WebRTC.PeerConnection.Simulcast.ApplyRemoteDescription";
+const char kSimulcastDisabled[] = "WebRTC.PeerConnection.Simulcast.Disabled";
+
+void NoteAddIceCandidateResult(int result) {
+ RTC_HISTOGRAM_ENUMERATION("WebRTC.PeerConnection.AddIceCandidate", result,
+ kAddIceCandidateMax);
+}
+
+void NoteKeyProtocolAndMedia(KeyExchangeProtocolType protocol_type,
+ cricket::MediaType media_type) {
+ // Array of structs needed to map {KeyExchangeProtocolType,
+ // cricket::MediaType} to KeyExchangeProtocolMedia without using std::map in
+ // order to avoid -Wglobal-constructors and -Wexit-time-destructors.
+ static constexpr struct {
+ KeyExchangeProtocolType protocol_type;
+ cricket::MediaType media_type;
+ KeyExchangeProtocolMedia protocol_media;
+ } kEnumCounterKeyProtocolMediaMap[] = {
+ {kEnumCounterKeyProtocolDtls, cricket::MEDIA_TYPE_AUDIO,
+ kEnumCounterKeyProtocolMediaTypeDtlsAudio},
+ {kEnumCounterKeyProtocolDtls, cricket::MEDIA_TYPE_VIDEO,
+ kEnumCounterKeyProtocolMediaTypeDtlsVideo},
+ {kEnumCounterKeyProtocolDtls, cricket::MEDIA_TYPE_DATA,
+ kEnumCounterKeyProtocolMediaTypeDtlsData},
+ {kEnumCounterKeyProtocolSdes, cricket::MEDIA_TYPE_AUDIO,
+ kEnumCounterKeyProtocolMediaTypeSdesAudio},
+ {kEnumCounterKeyProtocolSdes, cricket::MEDIA_TYPE_VIDEO,
+ kEnumCounterKeyProtocolMediaTypeSdesVideo},
+ {kEnumCounterKeyProtocolSdes, cricket::MEDIA_TYPE_DATA,
+ kEnumCounterKeyProtocolMediaTypeSdesData},
+ };
+
+ RTC_HISTOGRAM_ENUMERATION("WebRTC.PeerConnection.KeyProtocol", protocol_type,
+ kEnumCounterKeyProtocolMax);
+
+ for (const auto& i : kEnumCounterKeyProtocolMediaMap) {
+ if (i.protocol_type == protocol_type && i.media_type == media_type) {
+ RTC_HISTOGRAM_ENUMERATION("WebRTC.PeerConnection.KeyProtocolByMedia",
+ i.protocol_media,
+ kEnumCounterKeyProtocolMediaTypeMax);
+ }
+ }
+}
+
+// Returns true if |new_desc| requests an ICE restart (i.e., new ufrag/pwd).
+bool CheckForRemoteIceRestart(const SessionDescriptionInterface* old_desc,
+ const SessionDescriptionInterface* new_desc,
+ const std::string& content_name) {
+ if (!old_desc) {
+ return false;
+ }
+ const SessionDescription* new_sd = new_desc->description();
+ const SessionDescription* old_sd = old_desc->description();
+ const ContentInfo* cinfo = new_sd->GetContentByName(content_name);
+ if (!cinfo || cinfo->rejected) {
+ return false;
+ }
+ // If the content isn't rejected, check if ufrag and password has changed.
+ const cricket::TransportDescription* new_transport_desc =
+ new_sd->GetTransportDescriptionByName(content_name);
+ const cricket::TransportDescription* old_transport_desc =
+ old_sd->GetTransportDescriptionByName(content_name);
+ if (!new_transport_desc || !old_transport_desc) {
+ // No transport description exists. This is not an ICE restart.
+ return false;
+ }
+ if (cricket::IceCredentialsChanged(
+ old_transport_desc->ice_ufrag, old_transport_desc->ice_pwd,
+ new_transport_desc->ice_ufrag, new_transport_desc->ice_pwd)) {
+ RTC_LOG(LS_INFO) << "Remote peer requests ICE restart for " << content_name
+ << ".";
+ return true;
+ }
+ return false;
+}
+
+// Generates a string error message for SetLocalDescription/SetRemoteDescription
+// from an RTCError.
+std::string GetSetDescriptionErrorMessage(cricket::ContentSource source,
+ SdpType type,
+ const RTCError& error) {
+ rtc::StringBuilder oss;
+ oss << "Failed to set " << (source == cricket::CS_LOCAL ? "local" : "remote")
+ << " " << SdpTypeToString(type) << " sdp: " << error.message();
+ return oss.Release();
+}
+
+std::string GetStreamIdsString(rtc::ArrayView<const std::string> stream_ids) {
+ std::string output = "streams=[";
+ const char* separator = "";
+ for (const auto& stream_id : stream_ids) {
+ output.append(separator).append(stream_id);
+ separator = ", ";
+ }
+ output.append("]");
+ return output;
+}
+
+void ReportSimulcastApiVersion(const char* name,
+ const SessionDescription& session) {
+ bool has_legacy = false;
+ bool has_spec_compliant = false;
+ for (const ContentInfo& content : session.contents()) {
+ if (!content.media_description()) {
+ continue;
+ }
+ has_spec_compliant |= content.media_description()->HasSimulcast();
+ for (const StreamParams& sp : content.media_description()->streams()) {
+ has_legacy |= sp.has_ssrc_group(cricket::kSimSsrcGroupSemantics);
+ }
+ }
+
+ if (has_legacy) {
+ RTC_HISTOGRAM_ENUMERATION(name, kSimulcastApiVersionLegacy,
+ kSimulcastApiVersionMax);
+ }
+ if (has_spec_compliant) {
+ RTC_HISTOGRAM_ENUMERATION(name, kSimulcastApiVersionSpecCompliant,
+ kSimulcastApiVersionMax);
+ }
+ if (!has_legacy && !has_spec_compliant) {
+ RTC_HISTOGRAM_ENUMERATION(name, kSimulcastApiVersionNone,
+ kSimulcastApiVersionMax);
+ }
+}
+
+const ContentInfo* FindTransceiverMSection(
+ RtpTransceiverProxyWithInternal<RtpTransceiver>* transceiver,
+ const SessionDescriptionInterface* session_description) {
+ return transceiver->mid()
+ ? session_description->description()->GetContentByName(
+ *transceiver->mid())
+ : nullptr;
+}
+
+// If the direction is "recvonly" or "inactive", treat the description
+// as containing no streams.
+// See: https://code.google.com/p/webrtc/issues/detail?id=5054
+std::vector<cricket::StreamParams> GetActiveStreams(
+ const cricket::MediaContentDescription* desc) {
+ return RtpTransceiverDirectionHasSend(desc->direction())
+ ? desc->streams()
+ : std::vector<cricket::StreamParams>();
+}
+
+// Logic to decide if an m= section can be recycled. This means that the new
+// m= section is not rejected, but the old local or remote m= section is
+// rejected. |old_content_one| and |old_content_two| refer to the m= section
+// of the old remote and old local descriptions in no particular order.
+// We need to check both the old local and remote because either
+// could be the most current from the latest negotation.
+bool IsMediaSectionBeingRecycled(SdpType type,
+ const ContentInfo& content,
+ const ContentInfo* old_content_one,
+ const ContentInfo* old_content_two) {
+ return type == SdpType::kOffer && !content.rejected &&
+ ((old_content_one && old_content_one->rejected) ||
+ (old_content_two && old_content_two->rejected));
+}
+
+// Verify that the order of media sections in |new_desc| matches
+// |current_desc|. The number of m= sections in |new_desc| should be no
+// less than |current_desc|. In the case of checking an answer's
+// |new_desc|, the |current_desc| is the last offer that was set as the
+// local or remote. In the case of checking an offer's |new_desc| we
+// check against the local and remote descriptions stored from the last
+// negotiation, because either of these could be the most up to date for
+// possible rejected m sections. These are the |current_desc| and
+// |secondary_current_desc|.
+bool MediaSectionsInSameOrder(const SessionDescription& current_desc,
+ const SessionDescription* secondary_current_desc,
+ const SessionDescription& new_desc,
+ const SdpType type) {
+ if (current_desc.contents().size() > new_desc.contents().size()) {
+ return false;
+ }
+
+ for (size_t i = 0; i < current_desc.contents().size(); ++i) {
+ const cricket::ContentInfo* secondary_content_info = nullptr;
+ if (secondary_current_desc &&
+ i < secondary_current_desc->contents().size()) {
+ secondary_content_info = &secondary_current_desc->contents()[i];
+ }
+ if (IsMediaSectionBeingRecycled(type, new_desc.contents()[i],
+ ¤t_desc.contents()[i],
+ secondary_content_info)) {
+ // For new offer descriptions, if the media section can be recycled, it's
+ // valid for the MID and media type to change.
+ continue;
+ }
+ if (new_desc.contents()[i].name != current_desc.contents()[i].name) {
+ return false;
+ }
+ const MediaContentDescription* new_desc_mdesc =
+ new_desc.contents()[i].media_description();
+ const MediaContentDescription* current_desc_mdesc =
+ current_desc.contents()[i].media_description();
+ if (new_desc_mdesc->type() != current_desc_mdesc->type()) {
+ return false;
+ }
+ }
+ return true;
+}
+
+bool MediaSectionsHaveSameCount(const SessionDescription& desc1,
+ const SessionDescription& desc2) {
+ return desc1.contents().size() == desc2.contents().size();
+}
+// Checks that each non-rejected content has SDES crypto keys or a DTLS
+// fingerprint, unless it's in a BUNDLE group, in which case only the
+// BUNDLE-tag section (first media section/description in the BUNDLE group)
+// needs a ufrag and pwd. Mismatches, such as replying with a DTLS fingerprint
+// to SDES keys, will be caught in JsepTransport negotiation, and backstopped
+// by Channel's |srtp_required| check.
+RTCError VerifyCrypto(const SessionDescription* desc, bool dtls_enabled) {
+ const cricket::ContentGroup* bundle =
+ desc->GetGroupByName(cricket::GROUP_TYPE_BUNDLE);
+ for (const cricket::ContentInfo& content_info : desc->contents()) {
+ if (content_info.rejected) {
+ continue;
+ }
+ // Note what media is used with each crypto protocol, for all sections.
+ NoteKeyProtocolAndMedia(dtls_enabled ? webrtc::kEnumCounterKeyProtocolDtls
+ : webrtc::kEnumCounterKeyProtocolSdes,
+ content_info.media_description()->type());
+ const std::string& mid = content_info.name;
+ if (bundle && bundle->HasContentName(mid) &&
+ mid != *(bundle->FirstContentName())) {
+ // This isn't the first media section in the BUNDLE group, so it's not
+ // required to have crypto attributes, since only the crypto attributes
+ // from the first section actually get used.
+ continue;
+ }
+
+ // If the content isn't rejected or bundled into another m= section, crypto
+ // must be present.
+ const MediaContentDescription* media = content_info.media_description();
+ const TransportInfo* tinfo = desc->GetTransportInfoByName(mid);
+ if (!media || !tinfo) {
+ // Something is not right.
+ LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, kInvalidSdp);
+ }
+ if (dtls_enabled) {
+ if (!tinfo->description.identity_fingerprint) {
+ RTC_LOG(LS_WARNING)
+ << "Session description must have DTLS fingerprint if "
+ "DTLS enabled.";
+ return RTCError(RTCErrorType::INVALID_PARAMETER,
+ kSdpWithoutDtlsFingerprint);
+ }
+ } else {
+ if (media->cryptos().empty()) {
+ RTC_LOG(LS_WARNING)
+ << "Session description must have SDES when DTLS disabled.";
+ return RTCError(RTCErrorType::INVALID_PARAMETER, kSdpWithoutSdesCrypto);
+ }
+ }
+ }
+ return RTCError::OK();
+}
+
+// Checks that each non-rejected content has ice-ufrag and ice-pwd set, unless
+// it's in a BUNDLE group, in which case only the BUNDLE-tag section (first
+// media section/description in the BUNDLE group) needs a ufrag and pwd.
+bool VerifyIceUfragPwdPresent(const SessionDescription* desc) {
+ const cricket::ContentGroup* bundle =
+ desc->GetGroupByName(cricket::GROUP_TYPE_BUNDLE);
+ for (const cricket::ContentInfo& content_info : desc->contents()) {
+ if (content_info.rejected) {
+ continue;
+ }
+ const std::string& mid = content_info.name;
+ if (bundle && bundle->HasContentName(mid) &&
+ mid != *(bundle->FirstContentName())) {
+ // This isn't the first media section in the BUNDLE group, so it's not
+ // required to have ufrag/password, since only the ufrag/password from
+ // the first section actually get used.
+ continue;
+ }
+
+ // If the content isn't rejected or bundled into another m= section,
+ // ice-ufrag and ice-pwd must be present.
+ const TransportInfo* tinfo = desc->GetTransportInfoByName(mid);
+ if (!tinfo) {
+ // Something is not right.
+ RTC_LOG(LS_ERROR) << kInvalidSdp;
+ return false;
+ }
+ if (tinfo->description.ice_ufrag.empty() ||
+ tinfo->description.ice_pwd.empty()) {
+ RTC_LOG(LS_ERROR) << "Session description must have ice ufrag and pwd.";
+ return false;
+ }
+ }
+ return true;
+}
+
+static RTCError ValidateMids(const cricket::SessionDescription& description) {
+ std::set<std::string> mids;
+ for (const cricket::ContentInfo& content : description.contents()) {
+ if (content.name.empty()) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER,
+ "A media section is missing a MID attribute.");
+ }
+ if (!mids.insert(content.name).second) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER,
+ "Duplicate a=mid value '" + content.name + "'.");
+ }
+ }
+ return RTCError::OK();
+}
+
+bool IsValidOfferToReceiveMedia(int value) {
+ typedef PeerConnectionInterface::RTCOfferAnswerOptions Options;
+ return (value >= Options::kUndefined) &&
+ (value <= Options::kMaxOfferToReceiveMedia);
+}
+
+bool ValidateOfferAnswerOptions(
+ const PeerConnectionInterface::RTCOfferAnswerOptions& rtc_options) {
+ return IsValidOfferToReceiveMedia(rtc_options.offer_to_receive_audio) &&
+ IsValidOfferToReceiveMedia(rtc_options.offer_to_receive_video);
+}
+
+// Map internal signaling state name to spec name:
+// https://w3c.github.io/webrtc-pc/#rtcsignalingstate-enum
+std::string GetSignalingStateString(
+ PeerConnectionInterface::SignalingState state) {
+ switch (state) {
+ case PeerConnectionInterface::kStable:
+ return "stable";
+ case PeerConnectionInterface::kHaveLocalOffer:
+ return "have-local-offer";
+ case PeerConnectionInterface::kHaveLocalPrAnswer:
+ return "have-local-pranswer";
+ case PeerConnectionInterface::kHaveRemoteOffer:
+ return "have-remote-offer";
+ case PeerConnectionInterface::kHaveRemotePrAnswer:
+ return "have-remote-pranswer";
+ case PeerConnectionInterface::kClosed:
+ return "closed";
+ }
+ RTC_NOTREACHED();
+ return "";
+}
+
+// This method will extract any send encodings that were sent by the remote
+// connection. This is currently only relevant for Simulcast scenario (where
+// the number of layers may be communicated by the server).
+static std::vector<RtpEncodingParameters> GetSendEncodingsFromRemoteDescription(
+ const MediaContentDescription& desc) {
+ if (!desc.HasSimulcast()) {
+ return {};
+ }
+ std::vector<RtpEncodingParameters> result;
+ const SimulcastDescription& simulcast = desc.simulcast_description();
+
+ // This is a remote description, the parameters we are after should appear
+ // as receive streams.
+ for (const auto& alternatives : simulcast.receive_layers()) {
+ RTC_DCHECK(!alternatives.empty());
+ // There is currently no way to specify or choose from alternatives.
+ // We will always use the first alternative, which is the most preferred.
+ const SimulcastLayer& layer = alternatives[0];
+ RtpEncodingParameters parameters;
+ parameters.rid = layer.rid;
+ parameters.active = !layer.is_paused;
+ result.push_back(parameters);
+ }
+
+ return result;
+}
+
+static RTCError UpdateSimulcastLayerStatusInSender(
+ const std::vector<SimulcastLayer>& layers,
+ rtc::scoped_refptr<RtpSenderInternal> sender) {
+ RTC_DCHECK(sender);
+ RtpParameters parameters = sender->GetParametersInternal();
+ std::vector<std::string> disabled_layers;
+
+ // The simulcast envelope cannot be changed, only the status of the streams.
+ // So we will iterate over the send encodings rather than the layers.
+ for (RtpEncodingParameters& encoding : parameters.encodings) {
+ auto iter = std::find_if(layers.begin(), layers.end(),
+ [&encoding](const SimulcastLayer& layer) {
+ return layer.rid == encoding.rid;
+ });
+ // A layer that cannot be found may have been removed by the remote party.
+ if (iter == layers.end()) {
+ disabled_layers.push_back(encoding.rid);
+ continue;
+ }
+
+ encoding.active = !iter->is_paused;
+ }
+
+ RTCError result = sender->SetParametersInternal(parameters);
+ if (result.ok()) {
+ result = sender->DisableEncodingLayers(disabled_layers);
+ }
+
+ return result;
+}
+
+static bool SimulcastIsRejected(
+ const ContentInfo* local_content,
+ const MediaContentDescription& answer_media_desc) {
+ bool simulcast_offered = local_content &&
+ local_content->media_description() &&
+ local_content->media_description()->HasSimulcast();
+ bool simulcast_answered = answer_media_desc.HasSimulcast();
+ bool rids_supported = RtpExtension::FindHeaderExtensionByUri(
+ answer_media_desc.rtp_header_extensions(), RtpExtension::kRidUri);
+ return simulcast_offered && (!simulcast_answered || !rids_supported);
+}
+
+static RTCError DisableSimulcastInSender(
+ rtc::scoped_refptr<RtpSenderInternal> sender) {
+ RTC_DCHECK(sender);
+ RtpParameters parameters = sender->GetParametersInternal();
+ if (parameters.encodings.size() <= 1) {
+ return RTCError::OK();
+ }
+
+ std::vector<std::string> disabled_layers;
+ std::transform(
+ parameters.encodings.begin() + 1, parameters.encodings.end(),
+ std::back_inserter(disabled_layers),
+ [](const RtpEncodingParameters& encoding) { return encoding.rid; });
+ return sender->DisableEncodingLayers(disabled_layers);
+}
+
+} // namespace
+
+// Used by parameterless SetLocalDescription() to create an offer or answer.
+// Upon completion of creating the session description, SetLocalDescription() is
+// invoked with the result.
+class SdpOfferAnswerHandler::ImplicitCreateSessionDescriptionObserver
+ : public CreateSessionDescriptionObserver {
+ public:
+ ImplicitCreateSessionDescriptionObserver(
+ rtc::WeakPtr<SdpOfferAnswerHandler> sdp_handler,
+ rtc::scoped_refptr<SetLocalDescriptionObserverInterface>
+ set_local_description_observer)
+ : sdp_handler_(std::move(sdp_handler)),
+ set_local_description_observer_(
+ std::move(set_local_description_observer)) {}
+ ~ImplicitCreateSessionDescriptionObserver() override {
+ RTC_DCHECK(was_called_);
+ }
+
+ void SetOperationCompleteCallback(
+ std::function<void()> operation_complete_callback) {
+ operation_complete_callback_ = std::move(operation_complete_callback);
+ }
+
+ bool was_called() const { return was_called_; }
+
+ void OnSuccess(SessionDescriptionInterface* desc_ptr) override {
+ RTC_DCHECK(!was_called_);
+ std::unique_ptr<SessionDescriptionInterface> desc(desc_ptr);
+ was_called_ = true;
+
+ // Abort early if |pc_| is no longer valid.
+ if (!sdp_handler_) {
+ operation_complete_callback_();
+ return;
+ }
+ // DoSetLocalDescription() is a synchronous operation that invokes
+ // |set_local_description_observer_| with the result.
+ sdp_handler_->DoSetLocalDescription(
+ std::move(desc), std::move(set_local_description_observer_));
+ operation_complete_callback_();
+ }
+
+ void OnFailure(RTCError error) override {
+ RTC_DCHECK(!was_called_);
+ was_called_ = true;
+ set_local_description_observer_->OnSetLocalDescriptionComplete(RTCError(
+ error.type(), std::string("SetLocalDescription failed to create "
+ "session description - ") +
+ error.message()));
+ operation_complete_callback_();
+ }
+
+ private:
+ bool was_called_ = false;
+ rtc::WeakPtr<SdpOfferAnswerHandler> sdp_handler_;
+ rtc::scoped_refptr<SetLocalDescriptionObserverInterface>
+ set_local_description_observer_;
+ std::function<void()> operation_complete_callback_;
+};
+
+// Wraps a CreateSessionDescriptionObserver and an OperationsChain operation
+// complete callback. When the observer is invoked, the wrapped observer is
+// invoked followed by invoking the completion callback.
+class CreateSessionDescriptionObserverOperationWrapper
+ : public CreateSessionDescriptionObserver {
+ public:
+ CreateSessionDescriptionObserverOperationWrapper(
+ rtc::scoped_refptr<CreateSessionDescriptionObserver> observer,
+ std::function<void()> operation_complete_callback)
+ : observer_(std::move(observer)),
+ operation_complete_callback_(std::move(operation_complete_callback)) {
+ RTC_DCHECK(observer_);
+ }
+ ~CreateSessionDescriptionObserverOperationWrapper() override {
+ RTC_DCHECK(was_called_);
+ }
+
+ void OnSuccess(SessionDescriptionInterface* desc) override {
+ RTC_DCHECK(!was_called_);
+#ifdef RTC_DCHECK_IS_ON
+ was_called_ = true;
+#endif // RTC_DCHECK_IS_ON
+ // Completing the operation before invoking the observer allows the observer
+ // to execute SetLocalDescription() without delay.
+ operation_complete_callback_();
+ observer_->OnSuccess(desc);
+ }
+
+ void OnFailure(RTCError error) override {
+ RTC_DCHECK(!was_called_);
+#ifdef RTC_DCHECK_IS_ON
+ was_called_ = true;
+#endif // RTC_DCHECK_IS_ON
+ operation_complete_callback_();
+ observer_->OnFailure(std::move(error));
+ }
+
+ private:
+#ifdef RTC_DCHECK_IS_ON
+ bool was_called_ = false;
+#endif // RTC_DCHECK_IS_ON
+ rtc::scoped_refptr<CreateSessionDescriptionObserver> observer_;
+ std::function<void()> operation_complete_callback_;
+};
+
+// Wrapper for SetSessionDescriptionObserver that invokes the success or failure
+// callback in a posted message handled by the peer connection. This introduces
+// a delay that prevents recursive API calls by the observer, but this also
+// means that the PeerConnection can be modified before the observer sees the
+// result of the operation. This is ill-advised for synchronizing states.
+//
+// Implements both the SetLocalDescriptionObserverInterface and the
+// SetRemoteDescriptionObserverInterface.
+class SdpOfferAnswerHandler::SetSessionDescriptionObserverAdapter
+ : public SetLocalDescriptionObserverInterface,
+ public SetRemoteDescriptionObserverInterface {
+ public:
+ SetSessionDescriptionObserverAdapter(
+ rtc::WeakPtr<SdpOfferAnswerHandler> handler,
+ rtc::scoped_refptr<SetSessionDescriptionObserver> inner_observer)
+ : handler_(std::move(handler)),
+ inner_observer_(std::move(inner_observer)) {}
+
+ // SetLocalDescriptionObserverInterface implementation.
+ void OnSetLocalDescriptionComplete(RTCError error) override {
+ OnSetDescriptionComplete(std::move(error));
+ }
+ // SetRemoteDescriptionObserverInterface implementation.
+ void OnSetRemoteDescriptionComplete(RTCError error) override {
+ OnSetDescriptionComplete(std::move(error));
+ }
+
+ private:
+ void OnSetDescriptionComplete(RTCError error) {
+ if (!handler_)
+ return;
+ if (error.ok()) {
+ handler_->pc_->PostSetSessionDescriptionSuccess(inner_observer_);
+ } else {
+ handler_->pc_->PostSetSessionDescriptionFailure(inner_observer_,
+ std::move(error));
+ }
+ }
+
+ rtc::WeakPtr<SdpOfferAnswerHandler> handler_;
+ rtc::scoped_refptr<SetSessionDescriptionObserver> inner_observer_;
+};
+
+class SdpOfferAnswerHandler::LocalIceCredentialsToReplace {
+ public:
+ // Sets the ICE credentials that need restarting to the ICE credentials of
+ // the current and pending descriptions.
+ void SetIceCredentialsFromLocalDescriptions(
+ const SessionDescriptionInterface* current_local_description,
+ const SessionDescriptionInterface* pending_local_description) {
+ ice_credentials_.clear();
+ if (current_local_description) {
+ AppendIceCredentialsFromSessionDescription(*current_local_description);
+ }
+ if (pending_local_description) {
+ AppendIceCredentialsFromSessionDescription(*pending_local_description);
+ }
+ }
+
+ void ClearIceCredentials() { ice_credentials_.clear(); }
+
+ // Returns true if we have ICE credentials that need restarting.
+ bool HasIceCredentials() const { return !ice_credentials_.empty(); }
+
+ // Returns true if |local_description| shares no ICE credentials with the
+ // ICE credentials that need restarting.
+ bool SatisfiesIceRestart(
+ const SessionDescriptionInterface& local_description) const {
+ for (const auto& transport_info :
+ local_description.description()->transport_infos()) {
+ if (ice_credentials_.find(std::make_pair(
+ transport_info.description.ice_ufrag,
+ transport_info.description.ice_pwd)) != ice_credentials_.end()) {
+ return false;
+ }
+ }
+ return true;
+ }
+
+ private:
+ void AppendIceCredentialsFromSessionDescription(
+ const SessionDescriptionInterface& desc) {
+ for (const auto& transport_info : desc.description()->transport_infos()) {
+ ice_credentials_.insert(
+ std::make_pair(transport_info.description.ice_ufrag,
+ transport_info.description.ice_pwd));
+ }
+ }
+
+ std::set<std::pair<std::string, std::string>> ice_credentials_;
+};
+
+SdpOfferAnswerHandler::SdpOfferAnswerHandler(PeerConnection* pc)
+ : pc_(pc),
+ operations_chain_(rtc::OperationsChain::Create()),
+ local_ice_credentials_to_replace_(new LocalIceCredentialsToReplace()),
+ weak_ptr_factory_(this) {
+ operations_chain_->SetOnChainEmptyCallback(
+ [this_weak_ptr = weak_ptr_factory_.GetWeakPtr()]() {
+ if (!this_weak_ptr)
+ return;
+ this_weak_ptr->OnOperationsChainEmpty();
+ });
+}
+
+SdpOfferAnswerHandler::~SdpOfferAnswerHandler() {}
+
+void SdpOfferAnswerHandler::PrepareForShutdown() {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ weak_ptr_factory_.InvalidateWeakPtrs();
+}
+
+void SdpOfferAnswerHandler::Close() {
+ ChangeSignalingState(PeerConnectionInterface::kClosed);
+}
+
+void SdpOfferAnswerHandler::RestartIce() {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ local_ice_credentials_to_replace_->SetIceCredentialsFromLocalDescriptions(
+ current_local_description(), pending_local_description());
+ UpdateNegotiationNeeded();
+}
+
+rtc::Thread* SdpOfferAnswerHandler::signaling_thread() const {
+ return pc_->signaling_thread();
+}
+
+void SdpOfferAnswerHandler::CreateOffer(
+ CreateSessionDescriptionObserver* observer,
+ const PeerConnectionInterface::RTCOfferAnswerOptions& options) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ // Chain this operation. If asynchronous operations are pending on the chain,
+ // this operation will be queued to be invoked, otherwise the contents of the
+ // lambda will execute immediately.
+ operations_chain_->ChainOperation(
+ [this_weak_ptr = weak_ptr_factory_.GetWeakPtr(),
+ observer_refptr =
+ rtc::scoped_refptr<CreateSessionDescriptionObserver>(observer),
+ options](std::function<void()> operations_chain_callback) {
+ // Abort early if |this_weak_ptr| is no longer valid.
+ if (!this_weak_ptr) {
+ observer_refptr->OnFailure(
+ RTCError(RTCErrorType::INTERNAL_ERROR,
+ "CreateOffer failed because the session was shut down"));
+ operations_chain_callback();
+ return;
+ }
+ // The operation completes asynchronously when the wrapper is invoked.
+ rtc::scoped_refptr<CreateSessionDescriptionObserverOperationWrapper>
+ observer_wrapper(new rtc::RefCountedObject<
+ CreateSessionDescriptionObserverOperationWrapper>(
+ std::move(observer_refptr),
+ std::move(operations_chain_callback)));
+ this_weak_ptr->DoCreateOffer(options, observer_wrapper);
+ });
+}
+
+void SdpOfferAnswerHandler::SetLocalDescription(
+ SetSessionDescriptionObserver* observer,
+ SessionDescriptionInterface* desc_ptr) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ // Chain this operation. If asynchronous operations are pending on the chain,
+ // this operation will be queued to be invoked, otherwise the contents of the
+ // lambda will execute immediately.
+ operations_chain_->ChainOperation(
+ [this_weak_ptr = weak_ptr_factory_.GetWeakPtr(),
+ observer_refptr =
+ rtc::scoped_refptr<SetSessionDescriptionObserver>(observer),
+ desc = std::unique_ptr<SessionDescriptionInterface>(desc_ptr)](
+ std::function<void()> operations_chain_callback) mutable {
+ // Abort early if |this_weak_ptr| is no longer valid.
+ if (!this_weak_ptr) {
+ // For consistency with SetSessionDescriptionObserverAdapter whose
+ // posted messages doesn't get processed when the PC is destroyed, we
+ // do not inform |observer_refptr| that the operation failed.
+ operations_chain_callback();
+ return;
+ }
+ // SetSessionDescriptionObserverAdapter takes care of making sure the
+ // |observer_refptr| is invoked in a posted message.
+ this_weak_ptr->DoSetLocalDescription(
+ std::move(desc),
+ rtc::scoped_refptr<SetLocalDescriptionObserverInterface>(
+ new rtc::RefCountedObject<SetSessionDescriptionObserverAdapter>(
+ this_weak_ptr, observer_refptr)));
+ // For backwards-compatability reasons, we declare the operation as
+ // completed here (rather than in a post), so that the operation chain
+ // is not blocked by this operation when the observer is invoked. This
+ // allows the observer to trigger subsequent offer/answer operations
+ // synchronously if the operation chain is now empty.
+ operations_chain_callback();
+ });
+}
+
+void SdpOfferAnswerHandler::SetLocalDescription(
+ std::unique_ptr<SessionDescriptionInterface> desc,
+ rtc::scoped_refptr<SetLocalDescriptionObserverInterface> observer) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ // Chain this operation. If asynchronous operations are pending on the chain,
+ // this operation will be queued to be invoked, otherwise the contents of the
+ // lambda will execute immediately.
+ operations_chain_->ChainOperation(
+ [this_weak_ptr = weak_ptr_factory_.GetWeakPtr(), observer,
+ desc = std::move(desc)](
+ std::function<void()> operations_chain_callback) mutable {
+ // Abort early if |this_weak_ptr| is no longer valid.
+ if (!this_weak_ptr) {
+ observer->OnSetLocalDescriptionComplete(RTCError(
+ RTCErrorType::INTERNAL_ERROR,
+ "SetLocalDescription failed because the session was shut down"));
+ operations_chain_callback();
+ return;
+ }
+ this_weak_ptr->DoSetLocalDescription(std::move(desc), observer);
+ // DoSetLocalDescription() is implemented as a synchronous operation.
+ // The |observer| will already have been informed that it completed, and
+ // we can mark this operation as complete without any loose ends.
+ operations_chain_callback();
+ });
+}
+
+void SdpOfferAnswerHandler::SetLocalDescription(
+ SetSessionDescriptionObserver* observer) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ SetLocalDescription(
+ new rtc::RefCountedObject<SetSessionDescriptionObserverAdapter>(
+ weak_ptr_factory_.GetWeakPtr(), observer));
+}
+
+void SdpOfferAnswerHandler::SetLocalDescription(
+ rtc::scoped_refptr<SetLocalDescriptionObserverInterface> observer) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ // The |create_sdp_observer| handles performing DoSetLocalDescription() with
+ // the resulting description as well as completing the operation.
+ rtc::scoped_refptr<ImplicitCreateSessionDescriptionObserver>
+ create_sdp_observer(
+ new rtc::RefCountedObject<ImplicitCreateSessionDescriptionObserver>(
+ weak_ptr_factory_.GetWeakPtr(), observer));
+ // Chain this operation. If asynchronous operations are pending on the chain,
+ // this operation will be queued to be invoked, otherwise the contents of the
+ // lambda will execute immediately.
+ operations_chain_->ChainOperation(
+ [this_weak_ptr = weak_ptr_factory_.GetWeakPtr(),
+ create_sdp_observer](std::function<void()> operations_chain_callback) {
+ // The |create_sdp_observer| is responsible for completing the
+ // operation.
+ create_sdp_observer->SetOperationCompleteCallback(
+ std::move(operations_chain_callback));
+ // Abort early if |this_weak_ptr| is no longer valid. This triggers the
+ // same code path as if DoCreateOffer() or DoCreateAnswer() failed.
+ if (!this_weak_ptr) {
+ create_sdp_observer->OnFailure(RTCError(
+ RTCErrorType::INTERNAL_ERROR,
+ "SetLocalDescription failed because the session was shut down"));
+ return;
+ }
+ switch (this_weak_ptr->signaling_state()) {
+ case PeerConnectionInterface::kStable:
+ case PeerConnectionInterface::kHaveLocalOffer:
+ case PeerConnectionInterface::kHaveRemotePrAnswer:
+ // TODO(hbos): If [LastCreatedOffer] exists and still represents the
+ // current state of the system, use that instead of creating another
+ // offer.
+ this_weak_ptr->DoCreateOffer(
+ PeerConnectionInterface::RTCOfferAnswerOptions(),
+ create_sdp_observer);
+ break;
+ case PeerConnectionInterface::kHaveLocalPrAnswer:
+ case PeerConnectionInterface::kHaveRemoteOffer:
+ // TODO(hbos): If [LastCreatedAnswer] exists and still represents
+ // the current state of the system, use that instead of creating
+ // another answer.
+ this_weak_ptr->DoCreateAnswer(
+ PeerConnectionInterface::RTCOfferAnswerOptions(),
+ create_sdp_observer);
+ break;
+ case PeerConnectionInterface::kClosed:
+ create_sdp_observer->OnFailure(RTCError(
+ RTCErrorType::INVALID_STATE,
+ "SetLocalDescription called when PeerConnection is closed."));
+ break;
+ }
+ });
+}
+
+RTCError SdpOfferAnswerHandler::ApplyLocalDescription(
+ std::unique_ptr<SessionDescriptionInterface> desc) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ RTC_DCHECK(desc);
+
+ // Update stats here so that we have the most recent stats for tracks and
+ // streams that might be removed by updating the session description.
+ pc_->stats()->UpdateStats(PeerConnectionInterface::kStatsOutputLevelStandard);
+
+ // Take a reference to the old local description since it's used below to
+ // compare against the new local description. When setting the new local
+ // description, grab ownership of the replaced session description in case it
+ // is the same as |old_local_description|, to keep it alive for the duration
+ // of the method.
+ const SessionDescriptionInterface* old_local_description =
+ local_description();
+ std::unique_ptr<SessionDescriptionInterface> replaced_local_description;
+ SdpType type = desc->GetType();
+ if (type == SdpType::kAnswer) {
+ replaced_local_description = pending_local_description_
+ ? std::move(pending_local_description_)
+ : std::move(current_local_description_);
+ current_local_description_ = std::move(desc);
+ pending_local_description_ = nullptr;
+ current_remote_description_ = std::move(pending_remote_description_);
+ } else {
+ replaced_local_description = std::move(pending_local_description_);
+ pending_local_description_ = std::move(desc);
+ }
+ // The session description to apply now must be accessed by
+ // |local_description()|.
+ RTC_DCHECK(local_description());
+
+ // Report statistics about any use of simulcast.
+ ReportSimulcastApiVersion(kSimulcastVersionApplyLocalDescription,
+ *local_description()->description());
+
+ if (!is_caller_) {
+ if (remote_description()) {
+ // Remote description was applied first, so this PC is the callee.
+ is_caller_ = false;
+ } else {
+ // Local description is applied first, so this PC is the caller.
+ is_caller_ = true;
+ }
+ }
+
+ RTCError error = pc_->PushdownTransportDescription(cricket::CS_LOCAL, type);
+ if (!error.ok()) {
+ return error;
+ }
+
+ if (IsUnifiedPlan()) {
+ RTCError error = UpdateTransceiversAndDataChannels(
+ cricket::CS_LOCAL, *local_description(), old_local_description,
+ remote_description());
+ if (!error.ok()) {
+ return error;
+ }
+ std::vector<rtc::scoped_refptr<RtpTransceiverInterface>> remove_list;
+ std::vector<rtc::scoped_refptr<MediaStreamInterface>> removed_streams;
+ for (const auto& transceiver : pc_->transceivers_) {
+ if (transceiver->stopped()) {
+ continue;
+ }
+
+ // 2.2.7.1.1.(6-9): Set sender and receiver's transport slots.
+ // Note that code paths that don't set MID won't be able to use
+ // information about DTLS transports.
+ if (transceiver->mid()) {
+ auto dtls_transport =
+ pc_->LookupDtlsTransportByMidInternal(*transceiver->mid());
+ transceiver->internal()->sender_internal()->set_transport(
+ dtls_transport);
+ transceiver->internal()->receiver_internal()->set_transport(
+ dtls_transport);
+ }
+
+ const ContentInfo* content =
+ pc_->FindMediaSectionForTransceiver(transceiver, local_description());
+ if (!content) {
+ continue;
+ }
+ const MediaContentDescription* media_desc = content->media_description();
+ // 2.2.7.1.6: If description is of type "answer" or "pranswer", then run
+ // the following steps:
+ if (type == SdpType::kPrAnswer || type == SdpType::kAnswer) {
+ // 2.2.7.1.6.1: If direction is "sendonly" or "inactive", and
+ // transceiver's [[FiredDirection]] slot is either "sendrecv" or
+ // "recvonly", process the removal of a remote track for the media
+ // description, given transceiver, removeList, and muteTracks.
+ if (!RtpTransceiverDirectionHasRecv(media_desc->direction()) &&
+ (transceiver->internal()->fired_direction() &&
+ RtpTransceiverDirectionHasRecv(
+ *transceiver->internal()->fired_direction()))) {
+ pc_->ProcessRemovalOfRemoteTrack(transceiver, &remove_list,
+ &removed_streams);
+ }
+ // 2.2.7.1.6.2: Set transceiver's [[CurrentDirection]] and
+ // [[FiredDirection]] slots to direction.
+ transceiver->internal()->set_current_direction(media_desc->direction());
+ transceiver->internal()->set_fired_direction(media_desc->direction());
+ }
+ }
+ auto observer = pc_->Observer();
+ for (const auto& transceiver : remove_list) {
+ observer->OnRemoveTrack(transceiver->receiver());
+ }
+ for (const auto& stream : removed_streams) {
+ observer->OnRemoveStream(stream);
+ }
+ } else {
+ // Media channels will be created only when offer is set. These may use new
+ // transports just created by PushdownTransportDescription.
+ if (type == SdpType::kOffer) {
+ // TODO(bugs.webrtc.org/4676) - Handle CreateChannel failure, as new local
+ // description is applied. Restore back to old description.
+ RTCError error = pc_->CreateChannels(*local_description()->description());
+ if (!error.ok()) {
+ return error;
+ }
+ }
+ // Remove unused channels if MediaContentDescription is rejected.
+ pc_->RemoveUnusedChannels(local_description()->description());
+ }
+
+ error = UpdateSessionState(type, cricket::CS_LOCAL,
+ local_description()->description());
+ if (!error.ok()) {
+ return error;
+ }
+
+ if (remote_description()) {
+ // Now that we have a local description, we can push down remote candidates.
+ pc_->UseCandidatesInSessionDescription(remote_description());
+ }
+
+ pending_ice_restarts_.clear();
+ if (pc_->session_error() != PeerConnection::SessionError::kNone) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+ pc_->GetSessionErrorMsg());
+ }
+
+ // If setting the description decided our SSL role, allocate any necessary
+ // SCTP sids.
+ rtc::SSLRole role;
+ if (IsSctpLike(pc_->data_channel_type()) && pc_->GetSctpSslRole(&role)) {
+ pc_->data_channel_controller()->AllocateSctpSids(role);
+ }
+
+ if (IsUnifiedPlan()) {
+ for (const auto& transceiver : pc_->transceivers_) {
+ if (transceiver->stopped()) {
+ continue;
+ }
+ const ContentInfo* content =
+ pc_->FindMediaSectionForTransceiver(transceiver, local_description());
+ if (!content) {
+ continue;
+ }
+ cricket::ChannelInterface* channel = transceiver->internal()->channel();
+ if (content->rejected || !channel || channel->local_streams().empty()) {
+ // 0 is a special value meaning "this sender has no associated send
+ // stream". Need to call this so the sender won't attempt to configure
+ // a no longer existing stream and run into DCHECKs in the lower
+ // layers.
+ transceiver->internal()->sender_internal()->SetSsrc(0);
+ } else {
+ // Get the StreamParams from the channel which could generate SSRCs.
+ const std::vector<StreamParams>& streams = channel->local_streams();
+ transceiver->internal()->sender_internal()->set_stream_ids(
+ streams[0].stream_ids());
+ transceiver->internal()->sender_internal()->SetSsrc(
+ streams[0].first_ssrc());
+ }
+ }
+ } else {
+ // Plan B semantics.
+
+ // Update state and SSRC of local MediaStreams and DataChannels based on the
+ // local session description.
+ const cricket::ContentInfo* audio_content =
+ GetFirstAudioContent(local_description()->description());
+ if (audio_content) {
+ if (audio_content->rejected) {
+ pc_->RemoveSenders(cricket::MEDIA_TYPE_AUDIO);
+ } else {
+ const cricket::AudioContentDescription* audio_desc =
+ audio_content->media_description()->as_audio();
+ pc_->UpdateLocalSenders(audio_desc->streams(), audio_desc->type());
+ }
+ }
+
+ const cricket::ContentInfo* video_content =
+ GetFirstVideoContent(local_description()->description());
+ if (video_content) {
+ if (video_content->rejected) {
+ pc_->RemoveSenders(cricket::MEDIA_TYPE_VIDEO);
+ } else {
+ const cricket::VideoContentDescription* video_desc =
+ video_content->media_description()->as_video();
+ pc_->UpdateLocalSenders(video_desc->streams(), video_desc->type());
+ }
+ }
+ }
+
+ const cricket::ContentInfo* data_content =
+ GetFirstDataContent(local_description()->description());
+ if (data_content) {
+ const cricket::RtpDataContentDescription* rtp_data_desc =
+ data_content->media_description()->as_rtp_data();
+ // rtp_data_desc will be null if this is an SCTP description.
+ if (rtp_data_desc) {
+ pc_->data_channel_controller()->UpdateLocalRtpDataChannels(
+ rtp_data_desc->streams());
+ }
+ }
+
+ if (type == SdpType::kAnswer &&
+ local_ice_credentials_to_replace_->SatisfiesIceRestart(
+ *current_local_description_)) {
+ local_ice_credentials_to_replace_->ClearIceCredentials();
+ }
+
+ return RTCError::OK();
+}
+
+void SdpOfferAnswerHandler::SetRemoteDescription(
+ SetSessionDescriptionObserver* observer,
+ SessionDescriptionInterface* desc_ptr) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ // Chain this operation. If asynchronous operations are pending on the chain,
+ // this operation will be queued to be invoked, otherwise the contents of the
+ // lambda will execute immediately.
+ operations_chain_->ChainOperation(
+ [this_weak_ptr = weak_ptr_factory_.GetWeakPtr(),
+ observer_refptr =
+ rtc::scoped_refptr<SetSessionDescriptionObserver>(observer),
+ desc = std::unique_ptr<SessionDescriptionInterface>(desc_ptr)](
+ std::function<void()> operations_chain_callback) mutable {
+ // Abort early if |this_weak_ptr| is no longer valid.
+ if (!this_weak_ptr) {
+ // For consistency with SetSessionDescriptionObserverAdapter whose
+ // posted messages doesn't get processed when the PC is destroyed, we
+ // do not inform |observer_refptr| that the operation failed.
+ operations_chain_callback();
+ return;
+ }
+ // SetSessionDescriptionObserverAdapter takes care of making sure the
+ // |observer_refptr| is invoked in a posted message.
+ this_weak_ptr->DoSetRemoteDescription(
+ std::move(desc),
+ rtc::scoped_refptr<SetRemoteDescriptionObserverInterface>(
+ new rtc::RefCountedObject<SetSessionDescriptionObserverAdapter>(
+ this_weak_ptr, observer_refptr)));
+ // For backwards-compatability reasons, we declare the operation as
+ // completed here (rather than in a post), so that the operation chain
+ // is not blocked by this operation when the observer is invoked. This
+ // allows the observer to trigger subsequent offer/answer operations
+ // synchronously if the operation chain is now empty.
+ operations_chain_callback();
+ });
+}
+
+void SdpOfferAnswerHandler::SetRemoteDescription(
+ std::unique_ptr<SessionDescriptionInterface> desc,
+ rtc::scoped_refptr<SetRemoteDescriptionObserverInterface> observer) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ // Chain this operation. If asynchronous operations are pending on the chain,
+ // this operation will be queued to be invoked, otherwise the contents of the
+ // lambda will execute immediately.
+ operations_chain_->ChainOperation(
+ [this_weak_ptr = weak_ptr_factory_.GetWeakPtr(), observer,
+ desc = std::move(desc)](
+ std::function<void()> operations_chain_callback) mutable {
+ // Abort early if |this_weak_ptr| is no longer valid.
+ if (!this_weak_ptr) {
+ observer->OnSetRemoteDescriptionComplete(RTCError(
+ RTCErrorType::INTERNAL_ERROR,
+ "SetRemoteDescription failed because the session was shut down"));
+ operations_chain_callback();
+ return;
+ }
+ this_weak_ptr->DoSetRemoteDescription(std::move(desc),
+ std::move(observer));
+ // DoSetRemoteDescription() is implemented as a synchronous operation.
+ // The |observer| will already have been informed that it completed, and
+ // we can mark this operation as complete without any loose ends.
+ operations_chain_callback();
+ });
+}
+
+RTCError SdpOfferAnswerHandler::ApplyRemoteDescription(
+ std::unique_ptr<SessionDescriptionInterface> desc) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ RTC_DCHECK(desc);
+
+ // Update stats here so that we have the most recent stats for tracks and
+ // streams that might be removed by updating the session description.
+ pc_->stats()->UpdateStats(PeerConnectionInterface::kStatsOutputLevelStandard);
+
+ // Take a reference to the old remote description since it's used below to
+ // compare against the new remote description. When setting the new remote
+ // description, grab ownership of the replaced session description in case it
+ // is the same as |old_remote_description|, to keep it alive for the duration
+ // of the method.
+ const SessionDescriptionInterface* old_remote_description =
+ remote_description();
+ std::unique_ptr<SessionDescriptionInterface> replaced_remote_description;
+ SdpType type = desc->GetType();
+ if (type == SdpType::kAnswer) {
+ replaced_remote_description = pending_remote_description_
+ ? std::move(pending_remote_description_)
+ : std::move(current_remote_description_);
+ current_remote_description_ = std::move(desc);
+ pending_remote_description_ = nullptr;
+ current_local_description_ = std::move(pending_local_description_);
+ } else {
+ replaced_remote_description = std::move(pending_remote_description_);
+ pending_remote_description_ = std::move(desc);
+ }
+ // The session description to apply now must be accessed by
+ // |remote_description()|.
+ RTC_DCHECK(remote_description());
+
+ // Report statistics about any use of simulcast.
+ ReportSimulcastApiVersion(kSimulcastVersionApplyRemoteDescription,
+ *remote_description()->description());
+
+ RTCError error = pc_->PushdownTransportDescription(cricket::CS_REMOTE, type);
+ if (!error.ok()) {
+ return error;
+ }
+ // Transport and Media channels will be created only when offer is set.
+ if (IsUnifiedPlan()) {
+ RTCError error = UpdateTransceiversAndDataChannels(
+ cricket::CS_REMOTE, *remote_description(), local_description(),
+ old_remote_description);
+ if (!error.ok()) {
+ return error;
+ }
+ } else {
+ // Media channels will be created only when offer is set. These may use new
+ // transports just created by PushdownTransportDescription.
+ if (type == SdpType::kOffer) {
+ // TODO(mallinath) - Handle CreateChannel failure, as new local
+ // description is applied. Restore back to old description.
+ RTCError error =
+ pc_->CreateChannels(*remote_description()->description());
+ if (!error.ok()) {
+ return error;
+ }
+ }
+ // Remove unused channels if MediaContentDescription is rejected.
+ pc_->RemoveUnusedChannels(remote_description()->description());
+ }
+
+ // NOTE: Candidates allocation will be initiated only when
+ // SetLocalDescription is called.
+ error = UpdateSessionState(type, cricket::CS_REMOTE,
+ remote_description()->description());
+ if (!error.ok()) {
+ return error;
+ }
+
+ if (local_description() &&
+ !pc_->UseCandidatesInSessionDescription(remote_description())) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, kInvalidCandidates);
+ }
+
+ if (old_remote_description) {
+ for (const cricket::ContentInfo& content :
+ old_remote_description->description()->contents()) {
+ // Check if this new SessionDescription contains new ICE ufrag and
+ // password that indicates the remote peer requests an ICE restart.
+ // TODO(deadbeef): When we start storing both the current and pending
+ // remote description, this should reset pending_ice_restarts and compare
+ // against the current description.
+ if (CheckForRemoteIceRestart(old_remote_description, remote_description(),
+ content.name)) {
+ if (type == SdpType::kOffer) {
+ pending_ice_restarts_.insert(content.name);
+ }
+ } else {
+ // We retain all received candidates only if ICE is not restarted.
+ // When ICE is restarted, all previous candidates belong to an old
+ // generation and should not be kept.
+ // TODO(deadbeef): This goes against the W3C spec which says the remote
+ // description should only contain candidates from the last set remote
+ // description plus any candidates added since then. We should remove
+ // this once we're sure it won't break anything.
+ WebRtcSessionDescriptionFactory::CopyCandidatesFromSessionDescription(
+ old_remote_description, content.name, mutable_remote_description());
+ }
+ }
+ }
+
+ if (pc_->session_error() != PeerConnection::SessionError::kNone) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+ pc_->GetSessionErrorMsg());
+ }
+
+ // Set the the ICE connection state to connecting since the connection may
+ // become writable with peer reflexive candidates before any remote candidate
+ // is signaled.
+ // TODO(pthatcher): This is a short-term solution for crbug/446908. A real fix
+ // is to have a new signal the indicates a change in checking state from the
+ // transport and expose a new checking() member from transport that can be
+ // read to determine the current checking state. The existing SignalConnecting
+ // actually means "gathering candidates", so cannot be be used here.
+ if (remote_description()->GetType() != SdpType::kOffer &&
+ remote_description()->number_of_mediasections() > 0u &&
+ pc_->ice_connection_state() ==
+ PeerConnectionInterface::kIceConnectionNew) {
+ pc_->SetIceConnectionState(PeerConnectionInterface::kIceConnectionChecking);
+ }
+
+ // If setting the description decided our SSL role, allocate any necessary
+ // SCTP sids.
+ rtc::SSLRole role;
+ if (IsSctpLike(pc_->data_channel_type()) && pc_->GetSctpSslRole(&role)) {
+ pc_->data_channel_controller()->AllocateSctpSids(role);
+ }
+
+ if (IsUnifiedPlan()) {
+ std::vector<rtc::scoped_refptr<RtpTransceiverInterface>>
+ now_receiving_transceivers;
+ std::vector<rtc::scoped_refptr<RtpTransceiverInterface>> remove_list;
+ std::vector<rtc::scoped_refptr<MediaStreamInterface>> added_streams;
+ std::vector<rtc::scoped_refptr<MediaStreamInterface>> removed_streams;
+ for (const auto& transceiver : pc_->transceivers_) {
+ const ContentInfo* content = pc_->FindMediaSectionForTransceiver(
+ transceiver, remote_description());
+ if (!content) {
+ continue;
+ }
+ const MediaContentDescription* media_desc = content->media_description();
+ RtpTransceiverDirection local_direction =
+ RtpTransceiverDirectionReversed(media_desc->direction());
+ // Roughly the same as steps 2.2.8.6 of section 4.4.1.6 "Set the
+ // RTCSessionDescription: Set the associated remote streams given
+ // transceiver.[[Receiver]], msids, addList, and removeList".
+ // https://w3c.github.io/webrtc-pc/#set-the-rtcsessiondescription
+ if (RtpTransceiverDirectionHasRecv(local_direction)) {
+ std::vector<std::string> stream_ids;
+ if (!media_desc->streams().empty()) {
+ // The remote description has signaled the stream IDs.
+ stream_ids = media_desc->streams()[0].stream_ids();
+ }
+ pc_->transceiver_stable_states_by_transceivers_[transceiver]
+ .SetRemoteStreamIdsIfUnset(transceiver->receiver()->stream_ids());
+
+ RTC_LOG(LS_INFO) << "Processing the MSIDs for MID=" << content->name
+ << " (" << GetStreamIdsString(stream_ids) << ").";
+ SetAssociatedRemoteStreams(transceiver->internal()->receiver_internal(),
+ stream_ids, &added_streams,
+ &removed_streams);
+ // From the WebRTC specification, steps 2.2.8.5/6 of section 4.4.1.6
+ // "Set the RTCSessionDescription: If direction is sendrecv or recvonly,
+ // and transceiver's current direction is neither sendrecv nor recvonly,
+ // process the addition of a remote track for the media description.
+ if (!transceiver->fired_direction() ||
+ !RtpTransceiverDirectionHasRecv(*transceiver->fired_direction())) {
+ RTC_LOG(LS_INFO)
+ << "Processing the addition of a remote track for MID="
+ << content->name << ".";
+ now_receiving_transceivers.push_back(transceiver);
+ }
+ }
+ // 2.2.8.1.9: If direction is "sendonly" or "inactive", and transceiver's
+ // [[FiredDirection]] slot is either "sendrecv" or "recvonly", process the
+ // removal of a remote track for the media description, given transceiver,
+ // removeList, and muteTracks.
+ if (!RtpTransceiverDirectionHasRecv(local_direction) &&
+ (transceiver->fired_direction() &&
+ RtpTransceiverDirectionHasRecv(*transceiver->fired_direction()))) {
+ pc_->ProcessRemovalOfRemoteTrack(transceiver, &remove_list,
+ &removed_streams);
+ }
+ // 2.2.8.1.10: Set transceiver's [[FiredDirection]] slot to direction.
+ transceiver->internal()->set_fired_direction(local_direction);
+ // 2.2.8.1.11: If description is of type "answer" or "pranswer", then run
+ // the following steps:
+ if (type == SdpType::kPrAnswer || type == SdpType::kAnswer) {
+ // 2.2.8.1.11.1: Set transceiver's [[CurrentDirection]] slot to
+ // direction.
+ transceiver->internal()->set_current_direction(local_direction);
+ // 2.2.8.1.11.[3-6]: Set the transport internal slots.
+ if (transceiver->mid()) {
+ auto dtls_transport =
+ pc_->LookupDtlsTransportByMidInternal(*transceiver->mid());
+ transceiver->internal()->sender_internal()->set_transport(
+ dtls_transport);
+ transceiver->internal()->receiver_internal()->set_transport(
+ dtls_transport);
+ }
+ }
+ // 2.2.8.1.12: If the media description is rejected, and transceiver is
+ // not already stopped, stop the RTCRtpTransceiver transceiver.
+ if (content->rejected && !transceiver->stopped()) {
+ RTC_LOG(LS_INFO) << "Stopping transceiver for MID=" << content->name
+ << " since the media section was rejected.";
+ transceiver->internal()->StopTransceiverProcedure();
+ }
+ if (!content->rejected &&
+ RtpTransceiverDirectionHasRecv(local_direction)) {
+ if (!media_desc->streams().empty() &&
+ media_desc->streams()[0].has_ssrcs()) {
+ uint32_t ssrc = media_desc->streams()[0].first_ssrc();
+ transceiver->internal()->receiver_internal()->SetupMediaChannel(ssrc);
+ } else {
+ transceiver->internal()
+ ->receiver_internal()
+ ->SetupUnsignaledMediaChannel();
+ }
+ }
+ }
+ // Once all processing has finished, fire off callbacks.
+ auto observer = pc_->Observer();
+ for (const auto& transceiver : now_receiving_transceivers) {
+ pc_->stats()->AddTrack(transceiver->receiver()->track());
+ observer->OnTrack(transceiver);
+ observer->OnAddTrack(transceiver->receiver(),
+ transceiver->receiver()->streams());
+ }
+ for (const auto& stream : added_streams) {
+ observer->OnAddStream(stream);
+ }
+ for (const auto& transceiver : remove_list) {
+ observer->OnRemoveTrack(transceiver->receiver());
+ }
+ for (const auto& stream : removed_streams) {
+ observer->OnRemoveStream(stream);
+ }
+ }
+
+ const cricket::ContentInfo* audio_content =
+ GetFirstAudioContent(remote_description()->description());
+ const cricket::ContentInfo* video_content =
+ GetFirstVideoContent(remote_description()->description());
+ const cricket::AudioContentDescription* audio_desc =
+ GetFirstAudioContentDescription(remote_description()->description());
+ const cricket::VideoContentDescription* video_desc =
+ GetFirstVideoContentDescription(remote_description()->description());
+ const cricket::RtpDataContentDescription* rtp_data_desc =
+ GetFirstRtpDataContentDescription(remote_description()->description());
+
+ // Check if the descriptions include streams, just in case the peer supports
+ // MSID, but doesn't indicate so with "a=msid-semantic".
+ if (remote_description()->description()->msid_supported() ||
+ (audio_desc && !audio_desc->streams().empty()) ||
+ (video_desc && !video_desc->streams().empty())) {
+ remote_peer_supports_msid_ = true;
+ }
+
+ // We wait to signal new streams until we finish processing the description,
+ // since only at that point will new streams have all their tracks.
+ rtc::scoped_refptr<StreamCollection> new_streams(StreamCollection::Create());
+
+ if (!IsUnifiedPlan()) {
+ // TODO(steveanton): When removing RTP senders/receivers in response to a
+ // rejected media section, there is some cleanup logic that expects the
+ // voice/ video channel to still be set. But in this method the voice/video
+ // channel would have been destroyed by the SetRemoteDescription caller
+ // above so the cleanup that relies on them fails to run. The RemoveSenders
+ // calls should be moved to right before the DestroyChannel calls to fix
+ // this.
+
+ // Find all audio rtp streams and create corresponding remote AudioTracks
+ // and MediaStreams.
+ if (audio_content) {
+ if (audio_content->rejected) {
+ pc_->RemoveSenders(cricket::MEDIA_TYPE_AUDIO);
+ } else {
+ bool default_audio_track_needed =
+ !remote_peer_supports_msid_ &&
+ RtpTransceiverDirectionHasSend(audio_desc->direction());
+ pc_->UpdateRemoteSendersList(GetActiveStreams(audio_desc),
+ default_audio_track_needed,
+ audio_desc->type(), new_streams);
+ }
+ }
+
+ // Find all video rtp streams and create corresponding remote VideoTracks
+ // and MediaStreams.
+ if (video_content) {
+ if (video_content->rejected) {
+ pc_->RemoveSenders(cricket::MEDIA_TYPE_VIDEO);
+ } else {
+ bool default_video_track_needed =
+ !remote_peer_supports_msid_ &&
+ RtpTransceiverDirectionHasSend(video_desc->direction());
+ pc_->UpdateRemoteSendersList(GetActiveStreams(video_desc),
+ default_video_track_needed,
+ video_desc->type(), new_streams);
+ }
+ }
+
+ // If this is an RTP data transport, update the DataChannels with the
+ // information from the remote peer.
+ if (rtp_data_desc) {
+ pc_->data_channel_controller()->UpdateRemoteRtpDataChannels(
+ GetActiveStreams(rtp_data_desc));
+ }
+
+ // Iterate new_streams and notify the observer about new MediaStreams.
+ auto observer = pc_->Observer();
+ for (size_t i = 0; i < new_streams->count(); ++i) {
+ MediaStreamInterface* new_stream = new_streams->at(i);
+ pc_->stats()->AddStream(new_stream);
+ observer->OnAddStream(
+ rtc::scoped_refptr<MediaStreamInterface>(new_stream));
+ }
+
+ pc_->UpdateEndedRemoteMediaStreams();
+ }
+
+ if (type == SdpType::kAnswer &&
+ local_ice_credentials_to_replace_->SatisfiesIceRestart(
+ *current_local_description_)) {
+ local_ice_credentials_to_replace_->ClearIceCredentials();
+ }
+
+ return RTCError::OK();
+}
+
+void SdpOfferAnswerHandler::DoSetLocalDescription(
+ std::unique_ptr<SessionDescriptionInterface> desc,
+ rtc::scoped_refptr<SetLocalDescriptionObserverInterface> observer) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::DoSetLocalDescription");
+
+ if (!observer) {
+ RTC_LOG(LS_ERROR) << "SetLocalDescription - observer is NULL.";
+ return;
+ }
+
+ if (!desc) {
+ observer->OnSetLocalDescriptionComplete(
+ RTCError(RTCErrorType::INTERNAL_ERROR, "SessionDescription is NULL."));
+ return;
+ }
+
+ // If a session error has occurred the PeerConnection is in a possibly
+ // inconsistent state so fail right away.
+ if (pc_->session_error() != PeerConnection::SessionError::kNone) {
+ std::string error_message = pc_->GetSessionErrorMsg();
+ RTC_LOG(LS_ERROR) << "SetLocalDescription: " << error_message;
+ observer->OnSetLocalDescriptionComplete(
+ RTCError(RTCErrorType::INTERNAL_ERROR, std::move(error_message)));
+ return;
+ }
+
+ // For SLD we support only explicit rollback.
+ if (desc->GetType() == SdpType::kRollback) {
+ if (IsUnifiedPlan()) {
+ observer->OnSetLocalDescriptionComplete(Rollback(desc->GetType()));
+ } else {
+ observer->OnSetLocalDescriptionComplete(
+ RTCError(RTCErrorType::UNSUPPORTED_OPERATION,
+ "Rollback not supported in Plan B"));
+ }
+ return;
+ }
+
+ RTCError error = ValidateSessionDescription(desc.get(), cricket::CS_LOCAL);
+ if (!error.ok()) {
+ std::string error_message = GetSetDescriptionErrorMessage(
+ cricket::CS_LOCAL, desc->GetType(), error);
+ RTC_LOG(LS_ERROR) << error_message;
+ observer->OnSetLocalDescriptionComplete(
+ RTCError(RTCErrorType::INTERNAL_ERROR, std::move(error_message)));
+ return;
+ }
+
+ // Grab the description type before moving ownership to ApplyLocalDescription,
+ // which may destroy it before returning.
+ const SdpType type = desc->GetType();
+
+ error = ApplyLocalDescription(std::move(desc));
+ // |desc| may be destroyed at this point.
+
+ if (!error.ok()) {
+ // If ApplyLocalDescription fails, the PeerConnection could be in an
+ // inconsistent state, so act conservatively here and set the session error
+ // so that future calls to SetLocalDescription/SetRemoteDescription fail.
+ pc_->SetSessionError(PeerConnection::SessionError::kContent,
+ error.message());
+ std::string error_message =
+ GetSetDescriptionErrorMessage(cricket::CS_LOCAL, type, error);
+ RTC_LOG(LS_ERROR) << error_message;
+ observer->OnSetLocalDescriptionComplete(
+ RTCError(RTCErrorType::INTERNAL_ERROR, std::move(error_message)));
+ return;
+ }
+ RTC_DCHECK(local_description());
+
+ if (local_description()->GetType() == SdpType::kAnswer) {
+ pc_->RemoveStoppedTransceivers();
+
+ // TODO(deadbeef): We already had to hop to the network thread for
+ // MaybeStartGathering...
+ pc_->network_thread()->Invoke<void>(
+ RTC_FROM_HERE, rtc::Bind(&cricket::PortAllocator::DiscardCandidatePool,
+ pc_->port_allocator_.get()));
+ // Make UMA notes about what was agreed to.
+ pc_->ReportNegotiatedSdpSemantics(*local_description());
+ }
+
+ observer->OnSetLocalDescriptionComplete(RTCError::OK());
+ pc_->NoteUsageEvent(
+ PeerConnection::UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED);
+
+ // Check if negotiation is needed. We must do this after informing the
+ // observer that SetLocalDescription() has completed to ensure negotiation is
+ // not needed prior to the promise resolving.
+ if (IsUnifiedPlan()) {
+ bool was_negotiation_needed = is_negotiation_needed_;
+ UpdateNegotiationNeeded();
+ if (signaling_state() == PeerConnectionInterface::kStable &&
+ was_negotiation_needed && is_negotiation_needed_) {
+ // Legacy version.
+ pc_->Observer()->OnRenegotiationNeeded();
+ // Spec-compliant version; the event may get invalidated before firing.
+ GenerateNegotiationNeededEvent();
+ }
+ }
+
+ // MaybeStartGathering needs to be called after informing the observer so that
+ // we don't signal any candidates before signaling that SetLocalDescription
+ // completed.
+ pc_->transport_controller_->MaybeStartGathering();
+}
+
+void SdpOfferAnswerHandler::DoCreateOffer(
+ const PeerConnectionInterface::RTCOfferAnswerOptions& options,
+ rtc::scoped_refptr<CreateSessionDescriptionObserver> observer) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::DoCreateOffer");
+
+ if (!observer) {
+ RTC_LOG(LS_ERROR) << "CreateOffer - observer is NULL.";
+ return;
+ }
+
+ if (pc_->IsClosed()) {
+ std::string error = "CreateOffer called when PeerConnection is closed.";
+ RTC_LOG(LS_ERROR) << error;
+ pc_->PostCreateSessionDescriptionFailure(
+ observer, RTCError(RTCErrorType::INVALID_STATE, std::move(error)));
+ return;
+ }
+
+ // If a session error has occurred the PeerConnection is in a possibly
+ // inconsistent state so fail right away.
+ if (pc_->session_error() != PeerConnection::SessionError::kNone) {
+ std::string error_message = pc_->GetSessionErrorMsg();
+ RTC_LOG(LS_ERROR) << "CreateOffer: " << error_message;
+ pc_->PostCreateSessionDescriptionFailure(
+ observer,
+ RTCError(RTCErrorType::INTERNAL_ERROR, std::move(error_message)));
+ return;
+ }
+
+ if (!ValidateOfferAnswerOptions(options)) {
+ std::string error = "CreateOffer called with invalid options.";
+ RTC_LOG(LS_ERROR) << error;
+ pc_->PostCreateSessionDescriptionFailure(
+ observer, RTCError(RTCErrorType::INVALID_PARAMETER, std::move(error)));
+ return;
+ }
+
+ // Legacy handling for offer_to_receive_audio and offer_to_receive_video.
+ // Specified in WebRTC section 4.4.3.2 "Legacy configuration extensions".
+ if (IsUnifiedPlan()) {
+ RTCError error = pc_->HandleLegacyOfferOptions(options);
+ if (!error.ok()) {
+ pc_->PostCreateSessionDescriptionFailure(observer, std::move(error));
+ return;
+ }
+ }
+
+ cricket::MediaSessionOptions session_options;
+ pc_->GetOptionsForOffer(options, &session_options);
+ webrtc_session_desc_factory_->CreateOffer(observer, options, session_options);
+}
+
+void SdpOfferAnswerHandler::CreateAnswer(
+ CreateSessionDescriptionObserver* observer,
+ const PeerConnectionInterface::RTCOfferAnswerOptions& options) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ // Chain this operation. If asynchronous operations are pending on the chain,
+ // this operation will be queued to be invoked, otherwise the contents of the
+ // lambda will execute immediately.
+ operations_chain_->ChainOperation(
+ [this_weak_ptr = weak_ptr_factory_.GetWeakPtr(),
+ observer_refptr =
+ rtc::scoped_refptr<CreateSessionDescriptionObserver>(observer),
+ options](std::function<void()> operations_chain_callback) {
+ // Abort early if |this_weak_ptr| is no longer valid.
+ if (!this_weak_ptr) {
+ observer_refptr->OnFailure(RTCError(
+ RTCErrorType::INTERNAL_ERROR,
+ "CreateAnswer failed because the session was shut down"));
+ operations_chain_callback();
+ return;
+ }
+ // The operation completes asynchronously when the wrapper is invoked.
+ rtc::scoped_refptr<CreateSessionDescriptionObserverOperationWrapper>
+ observer_wrapper(new rtc::RefCountedObject<
+ CreateSessionDescriptionObserverOperationWrapper>(
+ std::move(observer_refptr),
+ std::move(operations_chain_callback)));
+ this_weak_ptr->DoCreateAnswer(options, observer_wrapper);
+ });
+}
+
+void SdpOfferAnswerHandler::DoCreateAnswer(
+ const PeerConnectionInterface::RTCOfferAnswerOptions& options,
+ rtc::scoped_refptr<CreateSessionDescriptionObserver> observer) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::DoCreateAnswer");
+ if (!observer) {
+ RTC_LOG(LS_ERROR) << "CreateAnswer - observer is NULL.";
+ return;
+ }
+
+ // If a session error has occurred the PeerConnection is in a possibly
+ // inconsistent state so fail right away.
+ if (pc_->session_error() != PeerConnection::SessionError::kNone) {
+ std::string error_message = pc_->GetSessionErrorMsg();
+ RTC_LOG(LS_ERROR) << "CreateAnswer: " << error_message;
+ pc_->PostCreateSessionDescriptionFailure(
+ observer,
+ RTCError(RTCErrorType::INTERNAL_ERROR, std::move(error_message)));
+ return;
+ }
+
+ if (!(signaling_state_ == PeerConnectionInterface::kHaveRemoteOffer ||
+ signaling_state_ == PeerConnectionInterface::kHaveLocalPrAnswer)) {
+ std::string error =
+ "PeerConnection cannot create an answer in a state other than "
+ "have-remote-offer or have-local-pranswer.";
+ RTC_LOG(LS_ERROR) << error;
+ pc_->PostCreateSessionDescriptionFailure(
+ observer, RTCError(RTCErrorType::INVALID_STATE, std::move(error)));
+ return;
+ }
+
+ // The remote description should be set if we're in the right state.
+ RTC_DCHECK(remote_description());
+
+ if (IsUnifiedPlan()) {
+ if (options.offer_to_receive_audio !=
+ PeerConnectionInterface::RTCOfferAnswerOptions::kUndefined) {
+ RTC_LOG(LS_WARNING) << "CreateAnswer: offer_to_receive_audio is not "
+ "supported with Unified Plan semantics. Use the "
+ "RtpTransceiver API instead.";
+ }
+ if (options.offer_to_receive_video !=
+ PeerConnectionInterface::RTCOfferAnswerOptions::kUndefined) {
+ RTC_LOG(LS_WARNING) << "CreateAnswer: offer_to_receive_video is not "
+ "supported with Unified Plan semantics. Use the "
+ "RtpTransceiver API instead.";
+ }
+ }
+
+ cricket::MediaSessionOptions session_options;
+ pc_->GetOptionsForAnswer(options, &session_options);
+ webrtc_session_desc_factory_->CreateAnswer(observer, session_options);
+}
+
+void SdpOfferAnswerHandler::DoSetRemoteDescription(
+ std::unique_ptr<SessionDescriptionInterface> desc,
+ rtc::scoped_refptr<SetRemoteDescriptionObserverInterface> observer) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::DoSetRemoteDescription");
+
+ if (!observer) {
+ RTC_LOG(LS_ERROR) << "SetRemoteDescription - observer is NULL.";
+ return;
+ }
+
+ if (!desc) {
+ observer->OnSetRemoteDescriptionComplete(RTCError(
+ RTCErrorType::INVALID_PARAMETER, "SessionDescription is NULL."));
+ return;
+ }
+
+ // If a session error has occurred the PeerConnection is in a possibly
+ // inconsistent state so fail right away.
+ if (pc_->session_error() != PeerConnection::SessionError::kNone) {
+ std::string error_message = pc_->GetSessionErrorMsg();
+ RTC_LOG(LS_ERROR) << "SetRemoteDescription: " << error_message;
+ observer->OnSetRemoteDescriptionComplete(
+ RTCError(RTCErrorType::INTERNAL_ERROR, std::move(error_message)));
+ return;
+ }
+ if (IsUnifiedPlan()) {
+ if (pc_->configuration()->enable_implicit_rollback) {
+ if (desc->GetType() == SdpType::kOffer &&
+ signaling_state() == PeerConnectionInterface::kHaveLocalOffer) {
+ Rollback(desc->GetType());
+ }
+ }
+ // Explicit rollback.
+ if (desc->GetType() == SdpType::kRollback) {
+ observer->OnSetRemoteDescriptionComplete(Rollback(desc->GetType()));
+ return;
+ }
+ } else if (desc->GetType() == SdpType::kRollback) {
+ observer->OnSetRemoteDescriptionComplete(
+ RTCError(RTCErrorType::UNSUPPORTED_OPERATION,
+ "Rollback not supported in Plan B"));
+ return;
+ }
+ if (desc->GetType() == SdpType::kOffer) {
+ // Report to UMA the format of the received offer.
+ pc_->ReportSdpFormatReceived(*desc);
+ }
+
+ // Handle remote descriptions missing a=mid lines for interop with legacy end
+ // points.
+ pc_->FillInMissingRemoteMids(desc->description());
+
+ RTCError error = ValidateSessionDescription(desc.get(), cricket::CS_REMOTE);
+ if (!error.ok()) {
+ std::string error_message = GetSetDescriptionErrorMessage(
+ cricket::CS_REMOTE, desc->GetType(), error);
+ RTC_LOG(LS_ERROR) << error_message;
+ observer->OnSetRemoteDescriptionComplete(
+ RTCError(error.type(), std::move(error_message)));
+ return;
+ }
+
+ // Grab the description type before moving ownership to
+ // ApplyRemoteDescription, which may destroy it before returning.
+ const SdpType type = desc->GetType();
+
+ error = ApplyRemoteDescription(std::move(desc));
+ // |desc| may be destroyed at this point.
+
+ if (!error.ok()) {
+ // If ApplyRemoteDescription fails, the PeerConnection could be in an
+ // inconsistent state, so act conservatively here and set the session error
+ // so that future calls to SetLocalDescription/SetRemoteDescription fail.
+ pc_->SetSessionError(PeerConnection::SessionError::kContent,
+ error.message());
+ std::string error_message =
+ GetSetDescriptionErrorMessage(cricket::CS_REMOTE, type, error);
+ RTC_LOG(LS_ERROR) << error_message;
+ observer->OnSetRemoteDescriptionComplete(
+ RTCError(error.type(), std::move(error_message)));
+ return;
+ }
+ RTC_DCHECK(remote_description());
+
+ if (type == SdpType::kAnswer) {
+ pc_->RemoveStoppedTransceivers();
+ // TODO(deadbeef): We already had to hop to the network thread for
+ // MaybeStartGathering...
+ pc_->network_thread()->Invoke<void>(
+ RTC_FROM_HERE, rtc::Bind(&cricket::PortAllocator::DiscardCandidatePool,
+ pc_->port_allocator_.get()));
+ // Make UMA notes about what was agreed to.
+ pc_->ReportNegotiatedSdpSemantics(*remote_description());
+ }
+
+ observer->OnSetRemoteDescriptionComplete(RTCError::OK());
+ pc_->NoteUsageEvent(
+ PeerConnection::UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED);
+
+ // Check if negotiation is needed. We must do this after informing the
+ // observer that SetRemoteDescription() has completed to ensure negotiation is
+ // not needed prior to the promise resolving.
+ if (IsUnifiedPlan()) {
+ bool was_negotiation_needed = is_negotiation_needed_;
+ UpdateNegotiationNeeded();
+ if (signaling_state() == PeerConnectionInterface::kStable &&
+ was_negotiation_needed && is_negotiation_needed_) {
+ // Legacy version.
+ pc_->Observer()->OnRenegotiationNeeded();
+ // Spec-compliant version; the event may get invalidated before firing.
+ GenerateNegotiationNeededEvent();
+ }
+ }
+}
+
+void SdpOfferAnswerHandler::SetAssociatedRemoteStreams(
+ rtc::scoped_refptr<RtpReceiverInternal> receiver,
+ const std::vector<std::string>& stream_ids,
+ std::vector<rtc::scoped_refptr<MediaStreamInterface>>* added_streams,
+ std::vector<rtc::scoped_refptr<MediaStreamInterface>>* removed_streams) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ std::vector<rtc::scoped_refptr<MediaStreamInterface>> media_streams;
+ for (const std::string& stream_id : stream_ids) {
+ rtc::scoped_refptr<MediaStreamInterface> stream =
+ pc_->remote_streams_internal()->find(stream_id);
+ if (!stream) {
+ stream = MediaStreamProxy::Create(rtc::Thread::Current(),
+ MediaStream::Create(stream_id));
+ pc_->remote_streams_internal()->AddStream(stream);
+ added_streams->push_back(stream);
+ }
+ media_streams.push_back(stream);
+ }
+ // Special case: "a=msid" missing, use random stream ID.
+ if (media_streams.empty() &&
+ !(remote_description()->description()->msid_signaling() &
+ cricket::kMsidSignalingMediaSection)) {
+ if (!missing_msid_default_stream_) {
+ missing_msid_default_stream_ = MediaStreamProxy::Create(
+ rtc::Thread::Current(), MediaStream::Create(rtc::CreateRandomUuid()));
+ added_streams->push_back(missing_msid_default_stream_);
+ }
+ media_streams.push_back(missing_msid_default_stream_);
+ }
+ std::vector<rtc::scoped_refptr<MediaStreamInterface>> previous_streams =
+ receiver->streams();
+ // SetStreams() will add/remove the receiver's track to/from the streams. This
+ // differs from the spec - the spec uses an "addList" and "removeList" to
+ // update the stream-track relationships in a later step. We do this earlier,
+ // changing the order of things, but the end-result is the same.
+ // TODO(hbos): When we remove remote_streams(), use set_stream_ids()
+ // instead. https://crbug.com/webrtc/9480
+ receiver->SetStreams(media_streams);
+ pc_->RemoveRemoteStreamsIfEmpty(previous_streams, removed_streams);
+}
+
+bool SdpOfferAnswerHandler::AddIceCandidate(
+ const IceCandidateInterface* ice_candidate) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::AddIceCandidate");
+ if (pc_->IsClosed()) {
+ RTC_LOG(LS_ERROR) << "AddIceCandidate: PeerConnection is closed.";
+ NoteAddIceCandidateResult(kAddIceCandidateFailClosed);
+ return false;
+ }
+
+ if (!remote_description()) {
+ RTC_LOG(LS_ERROR) << "AddIceCandidate: ICE candidates can't be added "
+ "without any remote session description.";
+ NoteAddIceCandidateResult(kAddIceCandidateFailNoRemoteDescription);
+ return false;
+ }
+
+ if (!ice_candidate) {
+ RTC_LOG(LS_ERROR) << "AddIceCandidate: Candidate is null.";
+ NoteAddIceCandidateResult(kAddIceCandidateFailNullCandidate);
+ return false;
+ }
+
+ bool valid = false;
+ bool ready = pc_->ReadyToUseRemoteCandidate(ice_candidate, nullptr, &valid);
+ if (!valid) {
+ NoteAddIceCandidateResult(kAddIceCandidateFailNotValid);
+ return false;
+ }
+
+ // Add this candidate to the remote session description.
+ if (!mutable_remote_description()->AddCandidate(ice_candidate)) {
+ RTC_LOG(LS_ERROR) << "AddIceCandidate: Candidate cannot be used.";
+ NoteAddIceCandidateResult(kAddIceCandidateFailInAddition);
+ return false;
+ }
+
+ if (ready) {
+ bool result = pc_->UseCandidate(ice_candidate);
+ if (result) {
+ pc_->NoteUsageEvent(
+ PeerConnection::UsageEvent::ADD_ICE_CANDIDATE_SUCCEEDED);
+ NoteAddIceCandidateResult(kAddIceCandidateSuccess);
+ } else {
+ NoteAddIceCandidateResult(kAddIceCandidateFailNotUsable);
+ }
+ return result;
+ } else {
+ RTC_LOG(LS_INFO) << "AddIceCandidate: Not ready to use candidate.";
+ NoteAddIceCandidateResult(kAddIceCandidateFailNotReady);
+ return true;
+ }
+}
+
+void SdpOfferAnswerHandler::AddIceCandidate(
+ std::unique_ptr<IceCandidateInterface> candidate,
+ std::function<void(RTCError)> callback) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ // Chain this operation. If asynchronous operations are pending on the chain,
+ // this operation will be queued to be invoked, otherwise the contents of the
+ // lambda will execute immediately.
+ operations_chain_->ChainOperation(
+ [this_weak_ptr = weak_ptr_factory_.GetWeakPtr(),
+ candidate = std::move(candidate), callback = std::move(callback)](
+ std::function<void()> operations_chain_callback) {
+ if (!this_weak_ptr) {
+ operations_chain_callback();
+ callback(RTCError(
+ RTCErrorType::INVALID_STATE,
+ "AddIceCandidate failed because the session was shut down"));
+ return;
+ }
+ if (!this_weak_ptr->AddIceCandidate(candidate.get())) {
+ operations_chain_callback();
+ // Fail with an error type and message consistent with Chromium.
+ // TODO(hbos): Fail with error types according to spec.
+ callback(RTCError(RTCErrorType::UNSUPPORTED_OPERATION,
+ "Error processing ICE candidate"));
+ return;
+ }
+ operations_chain_callback();
+ callback(RTCError::OK());
+ });
+}
+
+bool SdpOfferAnswerHandler::RemoveIceCandidates(
+ const std::vector<cricket::Candidate>& candidates) {
+ TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::RemoveIceCandidates");
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ if (pc_->IsClosed()) {
+ RTC_LOG(LS_ERROR) << "RemoveIceCandidates: PeerConnection is closed.";
+ return false;
+ }
+
+ if (!remote_description()) {
+ RTC_LOG(LS_ERROR) << "RemoveIceCandidates: ICE candidates can't be removed "
+ "without any remote session description.";
+ return false;
+ }
+
+ if (candidates.empty()) {
+ RTC_LOG(LS_ERROR) << "RemoveIceCandidates: candidates are empty.";
+ return false;
+ }
+
+ size_t number_removed =
+ mutable_remote_description()->RemoveCandidates(candidates);
+ if (number_removed != candidates.size()) {
+ RTC_LOG(LS_ERROR)
+ << "RemoveIceCandidates: Failed to remove candidates. Requested "
+ << candidates.size() << " but only " << number_removed
+ << " are removed.";
+ }
+
+ // Remove the candidates from the transport controller.
+ RTCError error =
+ pc_->transport_controller_->RemoveRemoteCandidates(candidates);
+ if (!error.ok()) {
+ RTC_LOG(LS_ERROR)
+ << "RemoveIceCandidates: Error when removing remote candidates: "
+ << error.message();
+ }
+ return true;
+}
+
+void SdpOfferAnswerHandler::AddLocalIceCandidate(
+ const JsepIceCandidate* candidate) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ if (local_description()) {
+ mutable_local_description()->AddCandidate(candidate);
+ }
+}
+
+void SdpOfferAnswerHandler::RemoveLocalIceCandidates(
+ const std::vector<cricket::Candidate>& candidates) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ if (local_description()) {
+ mutable_local_description()->RemoveCandidates(candidates);
+ }
+}
+
+const SessionDescriptionInterface* SdpOfferAnswerHandler::local_description()
+ const {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ return pending_local_description_ ? pending_local_description_.get()
+ : current_local_description_.get();
+}
+
+const SessionDescriptionInterface* SdpOfferAnswerHandler::remote_description()
+ const {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ return pending_remote_description_ ? pending_remote_description_.get()
+ : current_remote_description_.get();
+}
+
+const SessionDescriptionInterface*
+SdpOfferAnswerHandler::current_local_description() const {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ return current_local_description_.get();
+}
+
+const SessionDescriptionInterface*
+SdpOfferAnswerHandler::current_remote_description() const {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ return current_remote_description_.get();
+}
+
+const SessionDescriptionInterface*
+SdpOfferAnswerHandler::pending_local_description() const {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ return pending_local_description_.get();
+}
+
+const SessionDescriptionInterface*
+SdpOfferAnswerHandler::pending_remote_description() const {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ return pending_remote_description_.get();
+}
+
+PeerConnectionInterface::SignalingState SdpOfferAnswerHandler::signaling_state()
+ const {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ return signaling_state_;
+}
+
+void SdpOfferAnswerHandler::ChangeSignalingState(
+ PeerConnectionInterface::SignalingState signaling_state) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ if (signaling_state_ == signaling_state) {
+ return;
+ }
+ RTC_LOG(LS_INFO) << "Session: " << pc_->session_id() << " Old state: "
+ << GetSignalingStateString(signaling_state_)
+ << " New state: "
+ << GetSignalingStateString(signaling_state);
+ signaling_state_ = signaling_state;
+ pc_->Observer()->OnSignalingChange(signaling_state_);
+}
+
+RTCError SdpOfferAnswerHandler::UpdateSessionState(
+ SdpType type,
+ cricket::ContentSource source,
+ const cricket::SessionDescription* description) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+
+ // If there's already a pending error then no state transition should happen.
+ // But all call-sites should be verifying this before calling us!
+ RTC_DCHECK(pc_->session_error() == PeerConnection::SessionError::kNone);
+
+ // If this is answer-ish we're ready to let media flow.
+ if (type == SdpType::kPrAnswer || type == SdpType::kAnswer) {
+ pc_->EnableSending();
+ }
+
+ // Update the signaling state according to the specified state machine (see
+ // https://w3c.github.io/webrtc-pc/#rtcsignalingstate-enum).
+ if (type == SdpType::kOffer) {
+ ChangeSignalingState(source == cricket::CS_LOCAL
+ ? PeerConnectionInterface::kHaveLocalOffer
+ : PeerConnectionInterface::kHaveRemoteOffer);
+ } else if (type == SdpType::kPrAnswer) {
+ ChangeSignalingState(source == cricket::CS_LOCAL
+ ? PeerConnectionInterface::kHaveLocalPrAnswer
+ : PeerConnectionInterface::kHaveRemotePrAnswer);
+ } else {
+ RTC_DCHECK_RUN_ON(pc_->signaling_thread());
+ RTC_DCHECK(type == SdpType::kAnswer);
+ ChangeSignalingState(PeerConnectionInterface::kStable);
+ pc_->transceiver_stable_states_by_transceivers_.clear();
+ pc_->have_pending_rtp_data_channel_ = false;
+ }
+
+ // Update internal objects according to the session description's media
+ // descriptions.
+ RTCError error = pc_->PushdownMediaDescription(type, source);
+ if (!error.ok()) {
+ return error;
+ }
+
+ return RTCError::OK();
+}
+
+bool SdpOfferAnswerHandler::ShouldFireNegotiationNeededEvent(
+ uint32_t event_id) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ // Plan B? Always fire to conform with useless legacy behavior.
+ if (!IsUnifiedPlan()) {
+ return true;
+ }
+ // The event ID has been invalidated. Either negotiation is no longer needed
+ // or a newer negotiation needed event has been generated.
+ if (event_id != negotiation_needed_event_id_) {
+ return false;
+ }
+ // The chain is no longer empty, update negotiation needed when it becomes
+ // empty. This should generate a newer negotiation needed event, making this
+ // one obsolete.
+ if (!operations_chain_->IsEmpty()) {
+ // Since we just suppressed an event that would have been fired, if
+ // negotiation is still needed by the time the chain becomes empty again, we
+ // must make sure to generate another event if negotiation is needed then.
+ // This happens when |is_negotiation_needed_| goes from false to true, so we
+ // set it to false until UpdateNegotiationNeeded() is called.
+ is_negotiation_needed_ = false;
+ update_negotiation_needed_on_empty_chain_ = true;
+ return false;
+ }
+ // We must not fire if the signaling state is no longer "stable". If
+ // negotiation is still needed when we return to "stable", a new negotiation
+ // needed event will be generated, so this one can safely be suppressed.
+ if (signaling_state_ != PeerConnectionInterface::kStable) {
+ return false;
+ }
+ // All checks have passed - please fire "negotiationneeded" now!
+ return true;
+}
+
+RTCError SdpOfferAnswerHandler::Rollback(SdpType desc_type) {
+ auto state = signaling_state();
+ if (state != PeerConnectionInterface::kHaveLocalOffer &&
+ state != PeerConnectionInterface::kHaveRemoteOffer) {
+ return RTCError(RTCErrorType::INVALID_STATE,
+ "Called in wrong signalingState: " +
+ GetSignalingStateString(signaling_state()));
+ }
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ RTC_DCHECK(IsUnifiedPlan());
+ std::vector<rtc::scoped_refptr<MediaStreamInterface>> all_added_streams;
+ std::vector<rtc::scoped_refptr<MediaStreamInterface>> all_removed_streams;
+ std::vector<rtc::scoped_refptr<RtpReceiverInterface>> removed_receivers;
+
+ for (auto&& transceivers_stable_state_pair :
+ pc_->transceiver_stable_states_by_transceivers_) {
+ auto transceiver = transceivers_stable_state_pair.first;
+ auto state = transceivers_stable_state_pair.second;
+
+ if (state.remote_stream_ids()) {
+ std::vector<rtc::scoped_refptr<MediaStreamInterface>> added_streams;
+ std::vector<rtc::scoped_refptr<MediaStreamInterface>> removed_streams;
+ SetAssociatedRemoteStreams(transceiver->internal()->receiver_internal(),
+ state.remote_stream_ids().value(),
+ &added_streams, &removed_streams);
+ all_added_streams.insert(all_added_streams.end(), added_streams.begin(),
+ added_streams.end());
+ all_removed_streams.insert(all_removed_streams.end(),
+ removed_streams.begin(),
+ removed_streams.end());
+ if (!state.has_m_section() && !state.newly_created()) {
+ continue;
+ }
+ }
+
+ RTC_DCHECK(transceiver->internal()->mid().has_value());
+ pc_->DestroyTransceiverChannel(transceiver);
+
+ if (signaling_state() == PeerConnectionInterface::kHaveRemoteOffer &&
+ transceiver->receiver()) {
+ removed_receivers.push_back(transceiver->receiver());
+ }
+ if (state.newly_created()) {
+ if (transceiver->internal()->reused_for_addtrack()) {
+ transceiver->internal()->set_created_by_addtrack(true);
+ } else {
+ int remaining_transceiver_count = 0;
+ for (auto&& t : pc_->transceivers_) {
+ if (t != transceiver) {
+ pc_->transceivers_[remaining_transceiver_count++] = t;
+ }
+ }
+ pc_->transceivers_.resize(remaining_transceiver_count);
+ }
+ }
+ transceiver->internal()->sender_internal()->set_transport(nullptr);
+ transceiver->internal()->receiver_internal()->set_transport(nullptr);
+ transceiver->internal()->set_mid(state.mid());
+ transceiver->internal()->set_mline_index(state.mline_index());
+ }
+ pc_->transport_controller_->RollbackTransports();
+ {
+ RTC_DCHECK_RUN_ON(pc_->signaling_thread());
+ if (pc_->have_pending_rtp_data_channel_) {
+ pc_->DestroyDataChannelTransport();
+ pc_->have_pending_rtp_data_channel_ = false;
+ }
+ pc_->transceiver_stable_states_by_transceivers_.clear();
+ }
+ pending_local_description_.reset();
+ pending_remote_description_.reset();
+ ChangeSignalingState(PeerConnectionInterface::kStable);
+
+ // Once all processing has finished, fire off callbacks.
+ for (const auto& receiver : removed_receivers) {
+ pc_->Observer()->OnRemoveTrack(receiver);
+ }
+ for (const auto& stream : all_added_streams) {
+ pc_->Observer()->OnAddStream(stream);
+ }
+ for (const auto& stream : all_removed_streams) {
+ pc_->Observer()->OnRemoveStream(stream);
+ }
+
+ // The assumption is that in case of implicit rollback UpdateNegotiationNeeded
+ // gets called in SetRemoteDescription.
+ if (desc_type == SdpType::kRollback) {
+ UpdateNegotiationNeeded();
+ if (is_negotiation_needed_) {
+ // Legacy version.
+ pc_->Observer()->OnRenegotiationNeeded();
+ // Spec-compliant version; the event may get invalidated before firing.
+ GenerateNegotiationNeededEvent();
+ }
+ }
+ return RTCError::OK();
+}
+
+bool SdpOfferAnswerHandler::IsUnifiedPlan() const {
+ RTC_DCHECK_RUN_ON(pc_->signaling_thread());
+ return pc_->IsUnifiedPlan();
+}
+
+void SdpOfferAnswerHandler::OnOperationsChainEmpty() {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ if (pc_->IsClosed() || !update_negotiation_needed_on_empty_chain_)
+ return;
+ update_negotiation_needed_on_empty_chain_ = false;
+ // Firing when chain is empty is only supported in Unified Plan to avoid Plan
+ // B regressions. (In Plan B, onnegotiationneeded is already broken anyway, so
+ // firing it even more might just be confusing.)
+ if (IsUnifiedPlan()) {
+ UpdateNegotiationNeeded();
+ }
+}
+
+absl::optional<bool> SdpOfferAnswerHandler::is_caller() {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ return is_caller_;
+}
+
+bool SdpOfferAnswerHandler::HasNewIceCredentials() {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ return local_ice_credentials_to_replace_->HasIceCredentials();
+}
+
+bool SdpOfferAnswerHandler::IceRestartPending(
+ const std::string& content_name) const {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ return pending_ice_restarts_.find(content_name) !=
+ pending_ice_restarts_.end();
+}
+
+void SdpOfferAnswerHandler::UpdateNegotiationNeeded() {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ if (!IsUnifiedPlan()) {
+ pc_->Observer()->OnRenegotiationNeeded();
+ GenerateNegotiationNeededEvent();
+ return;
+ }
+
+ // In the spec, a task is queued here to run the following steps - this is
+ // meant to ensure we do not fire onnegotiationneeded prematurely if multiple
+ // changes are being made at once. In order to support Chromium's
+ // implementation where the JavaScript representation of the PeerConnection
+ // lives on a separate thread though, the queuing of a task is instead
+ // performed by the PeerConnectionObserver posting from the signaling thread
+ // to the JavaScript main thread that negotiation is needed. And because the
+ // Operations Chain lives on the WebRTC signaling thread,
+ // ShouldFireNegotiationNeededEvent() must be called before firing the event
+ // to ensure the Operations Chain is still empty and the event has not been
+ // invalidated.
+
+ // If connection's [[IsClosed]] slot is true, abort these steps.
+ if (pc_->IsClosed())
+ return;
+
+ // If connection's signaling state is not "stable", abort these steps.
+ if (signaling_state() != PeerConnectionInterface::kStable)
+ return;
+
+ // NOTE
+ // The negotiation-needed flag will be updated once the state transitions to
+ // "stable", as part of the steps for setting an RTCSessionDescription.
+
+ // If the result of checking if negotiation is needed is false, clear the
+ // negotiation-needed flag by setting connection's [[NegotiationNeeded]] slot
+ // to false, and abort these steps.
+ bool is_negotiation_needed = CheckIfNegotiationIsNeeded();
+ if (!is_negotiation_needed) {
+ is_negotiation_needed_ = false;
+ // Invalidate any negotiation needed event that may previosuly have been
+ // generated.
+ ++negotiation_needed_event_id_;
+ return;
+ }
+
+ // If connection's [[NegotiationNeeded]] slot is already true, abort these
+ // steps.
+ if (is_negotiation_needed_)
+ return;
+
+ // Set connection's [[NegotiationNeeded]] slot to true.
+ is_negotiation_needed_ = true;
+
+ // Queue a task that runs the following steps:
+ // If connection's [[IsClosed]] slot is true, abort these steps.
+ // If connection's [[NegotiationNeeded]] slot is false, abort these steps.
+ // Fire an event named negotiationneeded at connection.
+ pc_->Observer()->OnRenegotiationNeeded();
+ // Fire the spec-compliant version; when ShouldFireNegotiationNeededEvent() is
+ // used in the task queued by the observer, this event will only fire when the
+ // chain is empty.
+ GenerateNegotiationNeededEvent();
+}
+
+bool SdpOfferAnswerHandler::CheckIfNegotiationIsNeeded() {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ // 1. If any implementation-specific negotiation is required, as described at
+ // the start of this section, return true.
+
+ // 2. If connection.[[LocalIceCredentialsToReplace]] is not empty, return
+ // true.
+ if (local_ice_credentials_to_replace_->HasIceCredentials()) {
+ return true;
+ }
+
+ // 3. Let description be connection.[[CurrentLocalDescription]].
+ const SessionDescriptionInterface* description = current_local_description();
+ if (!description)
+ return true;
+
+ // 4. If connection has created any RTCDataChannels, and no m= section in
+ // description has been negotiated yet for data, return true.
+ if (pc_->data_channel_controller()->HasSctpDataChannels()) {
+ if (!cricket::GetFirstDataContent(description->description()->contents()))
+ return true;
+ }
+
+ // 5. For each transceiver in connection's set of transceivers, perform the
+ // following checks:
+ for (const auto& transceiver : pc_->transceivers_) {
+ const ContentInfo* current_local_msection =
+ FindTransceiverMSection(transceiver.get(), description);
+
+ const ContentInfo* current_remote_msection = FindTransceiverMSection(
+ transceiver.get(), current_remote_description());
+
+ // 5.4 If transceiver is stopped and is associated with an m= section,
+ // but the associated m= section is not yet rejected in
+ // connection.[[CurrentLocalDescription]] or
+ // connection.[[CurrentRemoteDescription]], return true.
+ if (transceiver->stopped()) {
+ RTC_DCHECK(transceiver->stopping());
+ if (current_local_msection && !current_local_msection->rejected &&
+ ((current_remote_msection && !current_remote_msection->rejected) ||
+ !current_remote_msection)) {
+ return true;
+ }
+ continue;
+ }
+
+ // 5.1 If transceiver.[[Stopping]] is true and transceiver.[[Stopped]] is
+ // false, return true.
+ if (transceiver->stopping() && !transceiver->stopped())
+ return true;
+
+ // 5.2 If transceiver isn't stopped and isn't yet associated with an m=
+ // section in description, return true.
+ if (!current_local_msection)
+ return true;
+
+ const MediaContentDescription* current_local_media_description =
+ current_local_msection->media_description();
+ // 5.3 If transceiver isn't stopped and is associated with an m= section
+ // in description then perform the following checks:
+
+ // 5.3.1 If transceiver.[[Direction]] is "sendrecv" or "sendonly", and the
+ // associated m= section in description either doesn't contain a single
+ // "a=msid" line, or the number of MSIDs from the "a=msid" lines in this
+ // m= section, or the MSID values themselves, differ from what is in
+ // transceiver.sender.[[AssociatedMediaStreamIds]], return true.
+ if (RtpTransceiverDirectionHasSend(transceiver->direction())) {
+ if (current_local_media_description->streams().size() == 0)
+ return true;
+
+ std::vector<std::string> msection_msids;
+ for (const auto& stream : current_local_media_description->streams()) {
+ for (const std::string& msid : stream.stream_ids())
+ msection_msids.push_back(msid);
+ }
+
+ std::vector<std::string> transceiver_msids =
+ transceiver->sender()->stream_ids();
+ if (msection_msids.size() != transceiver_msids.size())
+ return true;
+
+ absl::c_sort(transceiver_msids);
+ absl::c_sort(msection_msids);
+ if (transceiver_msids != msection_msids)
+ return true;
+ }
+
+ // 5.3.2 If description is of type "offer", and the direction of the
+ // associated m= section in neither connection.[[CurrentLocalDescription]]
+ // nor connection.[[CurrentRemoteDescription]] matches
+ // transceiver.[[Direction]], return true.
+ if (description->GetType() == SdpType::kOffer) {
+ if (!current_remote_description())
+ return true;
+
+ if (!current_remote_msection)
+ return true;
+
+ RtpTransceiverDirection current_local_direction =
+ current_local_media_description->direction();
+ RtpTransceiverDirection current_remote_direction =
+ current_remote_msection->media_description()->direction();
+ if (transceiver->direction() != current_local_direction &&
+ transceiver->direction() !=
+ RtpTransceiverDirectionReversed(current_remote_direction)) {
+ return true;
+ }
+ }
+
+ // 5.3.3 If description is of type "answer", and the direction of the
+ // associated m= section in the description does not match
+ // transceiver.[[Direction]] intersected with the offered direction (as
+ // described in [JSEP] (section 5.3.1.)), return true.
+ if (description->GetType() == SdpType::kAnswer) {
+ if (!remote_description())
+ return true;
+
+ const ContentInfo* offered_remote_msection =
+ FindTransceiverMSection(transceiver.get(), remote_description());
+
+ RtpTransceiverDirection offered_direction =
+ offered_remote_msection
+ ? offered_remote_msection->media_description()->direction()
+ : RtpTransceiverDirection::kInactive;
+
+ if (current_local_media_description->direction() !=
+ (RtpTransceiverDirectionIntersection(
+ transceiver->direction(),
+ RtpTransceiverDirectionReversed(offered_direction)))) {
+ return true;
+ }
+ }
+ }
+
+ // If all the preceding checks were performed and true was not returned,
+ // nothing remains to be negotiated; return false.
+ return false;
+}
+
+void SdpOfferAnswerHandler::GenerateNegotiationNeededEvent() {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ ++negotiation_needed_event_id_;
+ pc_->Observer()->OnNegotiationNeededEvent(negotiation_needed_event_id_);
+}
+
+RTCError SdpOfferAnswerHandler::ValidateSessionDescription(
+ const SessionDescriptionInterface* sdesc,
+ cricket::ContentSource source) {
+ if (pc_->session_error() != PeerConnection::SessionError::kNone) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+ pc_->GetSessionErrorMsg());
+ }
+
+ if (!sdesc || !sdesc->description()) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, kInvalidSdp);
+ }
+
+ SdpType type = sdesc->GetType();
+ if ((source == cricket::CS_LOCAL && !pc_->ExpectSetLocalDescription(type)) ||
+ (source == cricket::CS_REMOTE &&
+ !pc_->ExpectSetRemoteDescription(type))) {
+ LOG_AND_RETURN_ERROR(
+ RTCErrorType::INVALID_STATE,
+ "Called in wrong state: " + GetSignalingStateString(signaling_state()));
+ }
+
+ RTCError error = ValidateMids(*sdesc->description());
+ if (!error.ok()) {
+ return error;
+ }
+
+ // Verify crypto settings.
+ std::string crypto_error;
+ if (webrtc_session_desc_factory_->SdesPolicy() == cricket::SEC_REQUIRED ||
+ pc_->dtls_enabled()) {
+ RTCError crypto_error =
+ VerifyCrypto(sdesc->description(), pc_->dtls_enabled());
+ if (!crypto_error.ok()) {
+ return crypto_error;
+ }
+ }
+
+ // Verify ice-ufrag and ice-pwd.
+ if (!VerifyIceUfragPwdPresent(sdesc->description())) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER,
+ kSdpWithoutIceUfragPwd);
+ }
+
+ if (!pc_->ValidateBundleSettings(sdesc->description())) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER,
+ kBundleWithoutRtcpMux);
+ }
+
+ // TODO(skvlad): When the local rtcp-mux policy is Require, reject any
+ // m-lines that do not rtcp-mux enabled.
+
+ // Verify m-lines in Answer when compared against Offer.
+ if (type == SdpType::kPrAnswer || type == SdpType::kAnswer) {
+ // With an answer we want to compare the new answer session description with
+ // the offer's session description from the current negotiation.
+ const cricket::SessionDescription* offer_desc =
+ (source == cricket::CS_LOCAL) ? remote_description()->description()
+ : local_description()->description();
+ if (!MediaSectionsHaveSameCount(*offer_desc, *sdesc->description()) ||
+ !MediaSectionsInSameOrder(*offer_desc, nullptr, *sdesc->description(),
+ type)) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER,
+ kMlineMismatchInAnswer);
+ }
+ } else {
+ // The re-offers should respect the order of m= sections in current
+ // description. See RFC3264 Section 8 paragraph 4 for more details.
+ // With a re-offer, either the current local or current remote descriptions
+ // could be the most up to date, so we would like to check against both of
+ // them if they exist. It could be the case that one of them has a 0 port
+ // for a media section, but the other does not. This is important to check
+ // against in the case that we are recycling an m= section.
+ const cricket::SessionDescription* current_desc = nullptr;
+ const cricket::SessionDescription* secondary_current_desc = nullptr;
+ if (local_description()) {
+ current_desc = local_description()->description();
+ if (remote_description()) {
+ secondary_current_desc = remote_description()->description();
+ }
+ } else if (remote_description()) {
+ current_desc = remote_description()->description();
+ }
+ if (current_desc &&
+ !MediaSectionsInSameOrder(*current_desc, secondary_current_desc,
+ *sdesc->description(), type)) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER,
+ kMlineMismatchInSubsequentOffer);
+ }
+ }
+
+ if (IsUnifiedPlan()) {
+ // Ensure that each audio and video media section has at most one
+ // "StreamParams". This will return an error if receiving a session
+ // description from a "Plan B" endpoint which adds multiple tracks of the
+ // same type. With Unified Plan, there can only be at most one track per
+ // media section.
+ for (const ContentInfo& content : sdesc->description()->contents()) {
+ const MediaContentDescription& desc = *content.media_description();
+ if ((desc.type() == cricket::MEDIA_TYPE_AUDIO ||
+ desc.type() == cricket::MEDIA_TYPE_VIDEO) &&
+ desc.streams().size() > 1u) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER,
+ "Media section has more than one track specified "
+ "with a=ssrc lines which is not supported with "
+ "Unified Plan.");
+ }
+ }
+ }
+
+ return RTCError::OK();
+}
+
+RTCError SdpOfferAnswerHandler::UpdateTransceiversAndDataChannels(
+ cricket::ContentSource source,
+ const SessionDescriptionInterface& new_session,
+ const SessionDescriptionInterface* old_local_description,
+ const SessionDescriptionInterface* old_remote_description) {
+ RTC_DCHECK_RUN_ON(signaling_thread());
+ RTC_DCHECK(IsUnifiedPlan());
+
+ const cricket::ContentGroup* bundle_group = nullptr;
+ if (new_session.GetType() == SdpType::kOffer) {
+ auto bundle_group_or_error =
+ GetEarlyBundleGroup(*new_session.description());
+ if (!bundle_group_or_error.ok()) {
+ return bundle_group_or_error.MoveError();
+ }
+ bundle_group = bundle_group_or_error.MoveValue();
+ }
+
+ const ContentInfos& new_contents = new_session.description()->contents();
+ for (size_t i = 0; i < new_contents.size(); ++i) {
+ const cricket::ContentInfo& new_content = new_contents[i];
+ cricket::MediaType media_type = new_content.media_description()->type();
+ pc_->mid_generator()->AddKnownId(new_content.name);
+ if (media_type == cricket::MEDIA_TYPE_AUDIO ||
+ media_type == cricket::MEDIA_TYPE_VIDEO) {
+ const cricket::ContentInfo* old_local_content = nullptr;
+ if (old_local_description &&
+ i < old_local_description->description()->contents().size()) {
+ old_local_content =
+ &old_local_description->description()->contents()[i];
+ }
+ const cricket::ContentInfo* old_remote_content = nullptr;
+ if (old_remote_description &&
+ i < old_remote_description->description()->contents().size()) {
+ old_remote_content =
+ &old_remote_description->description()->contents()[i];
+ }
+ // In the case where an m-section has completed its rejection,
+ // and is not being reused, we do not expect a transceiver.
+ if (old_local_content && old_local_content->rejected &&
+ old_remote_content && old_remote_content->rejected &&
+ new_content.rejected) {
+ continue;
+ }
+ auto transceiver_or_error =
+ AssociateTransceiver(source, new_session.GetType(), i, new_content,
+ old_local_content, old_remote_content);
+ if (!transceiver_or_error.ok()) {
+ return transceiver_or_error.MoveError();
+ }
+ auto transceiver = transceiver_or_error.MoveValue();
+ RTCError error =
+ UpdateTransceiverChannel(transceiver, new_content, bundle_group);
+ if (!error.ok()) {
+ return error;
+ }
+ } else if (media_type == cricket::MEDIA_TYPE_DATA) {
+ if (pc_->GetDataMid() && new_content.name != *(pc_->GetDataMid())) {
+ // Ignore all but the first data section.
+ RTC_LOG(LS_INFO) << "Ignoring data media section with MID="
+ << new_content.name;
+ continue;
+ }
+ RTCError error = UpdateDataChannel(source, new_content, bundle_group);
+ if (!error.ok()) {
+ return error;
+ }
+ } else {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+ "Unknown section type.");
+ }
+ }
+
+ return RTCError::OK();
+}
+
+RTCErrorOr<rtc::scoped_refptr<RtpTransceiverProxyWithInternal<RtpTransceiver>>>
+SdpOfferAnswerHandler::AssociateTransceiver(
+ cricket::ContentSource source,
+ SdpType type,
+ size_t mline_index,
+ const ContentInfo& content,
+ const ContentInfo* old_local_content,
+ const ContentInfo* old_remote_content) {
+ RTC_DCHECK(IsUnifiedPlan());
+ // If this is an offer then the m= section might be recycled. If the m=
+ // section is being recycled (defined as: rejected in the current local or
+ // remote description and not rejected in new description), the transceiver
+ // should have been removed by RemoveStoppedTransceivers().
+ if (IsMediaSectionBeingRecycled(type, content, old_local_content,
+ old_remote_content)) {
+ const std::string& old_mid =
+ (old_local_content && old_local_content->rejected)
+ ? old_local_content->name
+ : old_remote_content->name;
+ auto old_transceiver = pc_->GetAssociatedTransceiver(old_mid);
+ // The transceiver should be disassociated in RemoveStoppedTransceivers()
+ RTC_DCHECK(!old_transceiver);
+ }
+ const MediaContentDescription* media_desc = content.media_description();
+ auto transceiver = pc_->GetAssociatedTransceiver(content.name);
+ if (source == cricket::CS_LOCAL) {
+ // Find the RtpTransceiver that corresponds to this m= section, using the
+ // mapping between transceivers and m= section indices established when
+ // creating the offer.
+ if (!transceiver) {
+ transceiver = pc_->GetTransceiverByMLineIndex(mline_index);
+ }
+ if (!transceiver) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER,
+ "Unknown transceiver");
+ }
+ } else {
+ RTC_DCHECK_EQ(source, cricket::CS_REMOTE);
+ // If the m= section is sendrecv or recvonly, and there are RtpTransceivers
+ // of the same type...
+ // When simulcast is requested, a transceiver cannot be associated because
+ // AddTrack cannot be called to initialize it.
+ if (!transceiver &&
+ RtpTransceiverDirectionHasRecv(media_desc->direction()) &&
+ !media_desc->HasSimulcast()) {
+ transceiver = pc_->FindAvailableTransceiverToReceive(media_desc->type());
+ }
+ // If no RtpTransceiver was found in the previous step, create one with a
+ // recvonly direction.
+ if (!transceiver) {
+ RTC_LOG(LS_INFO) << "Adding "
+ << cricket::MediaTypeToString(media_desc->type())
+ << " transceiver for MID=" << content.name
+ << " at i=" << mline_index
+ << " in response to the remote description.";
+ std::string sender_id = rtc::CreateRandomUuid();
+ std::vector<RtpEncodingParameters> send_encodings =
+ GetSendEncodingsFromRemoteDescription(*media_desc);
+ auto sender = pc_->CreateSender(media_desc->type(), sender_id, nullptr,
+ {}, send_encodings);
+ std::string receiver_id;
+ if (!media_desc->streams().empty()) {
+ receiver_id = media_desc->streams()[0].id;
+ } else {
+ receiver_id = rtc::CreateRandomUuid();
+ }
+ auto receiver = pc_->CreateReceiver(media_desc->type(), receiver_id);
+ transceiver = pc_->CreateAndAddTransceiver(sender, receiver);
+ transceiver->internal()->set_direction(
+ RtpTransceiverDirection::kRecvOnly);
+ if (type == SdpType::kOffer) {
+ pc_->transceiver_stable_states_by_transceivers_[transceiver]
+ .set_newly_created();
+ }
+ }
+ // Check if the offer indicated simulcast but the answer rejected it.
+ // This can happen when simulcast is not supported on the remote party.
+ if (SimulcastIsRejected(old_local_content, *media_desc)) {
+ RTC_HISTOGRAM_BOOLEAN(kSimulcastDisabled, true);
+ RTCError error =
+ DisableSimulcastInSender(transceiver->internal()->sender_internal());
+ if (!error.ok()) {
+ RTC_LOG(LS_ERROR) << "Failed to remove rejected simulcast.";
+ return std::move(error);
+ }
+ }
+ }
+ RTC_DCHECK(transceiver);
+ if (transceiver->media_type() != media_desc->type()) {
+ LOG_AND_RETURN_ERROR(
+ RTCErrorType::INVALID_PARAMETER,
+ "Transceiver type does not match media description type.");
+ }
+ if (media_desc->HasSimulcast()) {
+ std::vector<SimulcastLayer> layers =
+ source == cricket::CS_LOCAL
+ ? media_desc->simulcast_description().send_layers().GetAllLayers()
+ : media_desc->simulcast_description()
+ .receive_layers()
+ .GetAllLayers();
+ RTCError error = UpdateSimulcastLayerStatusInSender(
+ layers, transceiver->internal()->sender_internal());
+ if (!error.ok()) {
+ RTC_LOG(LS_ERROR) << "Failed updating status for simulcast layers.";
+ return std::move(error);
+ }
+ }
+ if (type == SdpType::kOffer) {
+ bool state_changes = transceiver->internal()->mid() != content.name ||
+ transceiver->internal()->mline_index() != mline_index;
+ if (state_changes) {
+ pc_->transceiver_stable_states_by_transceivers_[transceiver]
+ .SetMSectionIfUnset(transceiver->internal()->mid(),
+ transceiver->internal()->mline_index());
+ }
+ }
+ // Associate the found or created RtpTransceiver with the m= section by
+ // setting the value of the RtpTransceiver's mid property to the MID of the m=
+ // section, and establish a mapping between the transceiver and the index of
+ // the m= section.
+ transceiver->internal()->set_mid(content.name);
+ transceiver->internal()->set_mline_index(mline_index);
+ return std::move(transceiver);
+}
+
+RTCErrorOr<const cricket::ContentGroup*>
+SdpOfferAnswerHandler::GetEarlyBundleGroup(
+ const SessionDescription& desc) const {
+ const cricket::ContentGroup* bundle_group = nullptr;
+ if (pc_->configuration()->bundle_policy ==
+ PeerConnectionInterface::kBundlePolicyMaxBundle) {
+ bundle_group = desc.GetGroupByName(cricket::GROUP_TYPE_BUNDLE);
+ if (!bundle_group) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER,
+ "max-bundle configured but session description "
+ "has no BUNDLE group");
+ }
+ }
+ return bundle_group;
+}
+
+RTCError SdpOfferAnswerHandler::UpdateTransceiverChannel(
+ rtc::scoped_refptr<RtpTransceiverProxyWithInternal<RtpTransceiver>>
+ transceiver,
+ const cricket::ContentInfo& content,
+ const cricket::ContentGroup* bundle_group) {
+ RTC_DCHECK(IsUnifiedPlan());
+ RTC_DCHECK(transceiver);
+ cricket::ChannelInterface* channel = transceiver->internal()->channel();
+ if (content.rejected) {
+ if (channel) {
+ transceiver->internal()->SetChannel(nullptr);
+ pc_->DestroyChannelInterface(channel);
+ }
+ } else {
+ if (!channel) {
+ if (transceiver->media_type() == cricket::MEDIA_TYPE_AUDIO) {
+ channel = pc_->CreateVoiceChannel(content.name);
+ } else {
+ RTC_DCHECK_EQ(cricket::MEDIA_TYPE_VIDEO, transceiver->media_type());
+ channel = pc_->CreateVideoChannel(content.name);
+ }
+ if (!channel) {
+ LOG_AND_RETURN_ERROR(
+ RTCErrorType::INTERNAL_ERROR,
+ "Failed to create channel for mid=" + content.name);
+ }
+ transceiver->internal()->SetChannel(channel);
+ }
+ }
+ return RTCError::OK();
+}
+
+RTCError SdpOfferAnswerHandler::UpdateDataChannel(
+ cricket::ContentSource source,
+ const cricket::ContentInfo& content,
+ const cricket::ContentGroup* bundle_group) {
+ if (pc_->data_channel_type() == cricket::DCT_NONE) {
+ // If data channels are disabled, ignore this media section. CreateAnswer
+ // will take care of rejecting it.
+ return RTCError::OK();
+ }
+ if (content.rejected) {
+ RTC_LOG(LS_INFO) << "Rejected data channel, mid=" << content.mid();
+ pc_->DestroyDataChannelTransport();
+ } else {
+ if (!pc_->data_channel_controller_.rtp_data_channel() &&
+ !pc_->data_channel_controller_.data_channel_transport()) {
+ RTC_LOG(LS_INFO) << "Creating data channel, mid=" << content.mid();
+ if (!pc_->CreateDataChannel(content.name)) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+ "Failed to create data channel.");
+ }
+ }
+ if (source == cricket::CS_REMOTE) {
+ const MediaContentDescription* data_desc = content.media_description();
+ if (data_desc && cricket::IsRtpProtocol(data_desc->protocol())) {
+ pc_->data_channel_controller_.UpdateRemoteRtpDataChannels(
+ GetActiveStreams(data_desc));
+ }
+ }
+ }
+ return RTCError::OK();
+}
+
+} // namespace webrtc
