/* * 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.
*/
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;
// Error messages constchar kInvalidSdp[] = "Invalid session description."; constchar kInvalidCandidates[] = "Description contains invalid candidates."; constchar kBundleWithoutRtcpMux[] = "rtcp-mux must be enabled when BUNDLE " "is enabled."; constchar kMlineMismatchInAnswer[] = "The order of m-lines in answer doesn't match order in offer. Rejecting " "answer."; constchar kMlineMismatchInSubsequentOffer[] = "The order of m-lines in subsequent offer doesn't match order from " "previous offer/answer."; constchar kSdpWithoutIceUfragPwd[] = "Called with SDP without ice-ufrag and ice-pwd."; constchar kSdpWithoutDtlsFingerprint[] = "Called with SDP without DTLS fingerprint."; constchar kSdpWithoutCrypto[] = "Called with SDP without crypto setup.";
// 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()) { returnfalse;
}
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) { returnfalse;
} 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()) { returnfalse;
}
} returntrue;
}
bool MediaSectionsHaveSameCount(const SessionDescription& desc1, const SessionDescription& desc2) { return desc1.contents().size() == desc2.contents().size();
} // Checks that each non-rejected content has 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 std::map<std::string, const cricket::ContentGroup*>&
bundle_groups_by_mid) { for (const cricket::ContentInfo& content_info : desc->contents()) { if (content_info.rejected) { continue;
} const std::string& mid = content_info.name; auto it = bundle_groups_by_mid.find(mid); const cricket::ContentGroup* bundle =
it != bundle_groups_by_mid.end() ? it->second : nullptr; if (bundle && 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) {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER,
kSdpWithoutDtlsFingerprint);
}
} else {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, kSdpWithoutCrypto);
}
} 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 std::map<std::string, const cricket::ContentGroup*>&
bundle_groups_by_mid) { for (const cricket::ContentInfo& content_info : desc->contents()) { if (content_info.rejected) { continue;
} const std::string& mid = content_info.name; auto it = bundle_groups_by_mid.find(mid); const cricket::ContentGroup* bundle =
it != bundle_groups_by_mid.end() ? it->second : nullptr; if (bundle && 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; returnfalse;
} if (tinfo->description.ice_ufrag.empty() ||
tinfo->description.ice_pwd.empty()) {
RTC_LOG(LS_ERROR) << "Session description must have ice ufrag and pwd."; returnfalse;
}
} returntrue;
}
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 (content.name.size() > kMidMaxSize) {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, "The MID attribute exceeds the maximum supported " "length of 16 characters.");
} if (!mids.insert(content.name).second) {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, "Duplicate a=mid value '" + content.name + "'.");
}
} return RTCError::OK();
}
RTCError FindDuplicateCodecParameters( const RtpCodecParameters codec_parameters,
std::map<int, RtpCodecParameters>& payload_to_codec_parameters) { auto existing_codec_parameters =
payload_to_codec_parameters.find(codec_parameters.payload_type); if (existing_codec_parameters != payload_to_codec_parameters.end() &&
codec_parameters != existing_codec_parameters->second) {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, "A BUNDLE group contains a codec collision for " "payload_type='" +
rtc::ToString(codec_parameters.payload_type) + ". All codecs must share the same type, " "encoding name, clock rate and parameters.");
}
payload_to_codec_parameters.insert(
std::make_pair(codec_parameters.payload_type, codec_parameters)); return RTCError::OK();
}
RTCError ValidateBundledPayloadTypes( const cricket::SessionDescription& description) { // https://www.rfc-editor.org/rfc/rfc8843#name-payload-type-pt-value-reuse // ... all codecs associated with the payload type number MUST share an // identical codec configuration. This means that the codecs MUST share // the same media type, encoding name, clock rate, and any parameter // that can affect the codec configuration and packetization.
std::vector<const cricket::ContentGroup*> bundle_groups =
description.GetGroupsByName(cricket::GROUP_TYPE_BUNDLE); for (const cricket::ContentGroup* bundle_group : bundle_groups) {
std::map<int, RtpCodecParameters> payload_to_codec_parameters; for (const std::string& content_name : bundle_group->content_names()) { const ContentInfo* content_description =
description.GetContentByName(content_name); if (!content_description) {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, "A BUNDLE group contains a MID='" + content_name + "' matching no m= section.");
} const cricket::MediaContentDescription* media_description =
content_description->media_description();
RTC_DCHECK(media_description); if (content_description->rejected || !media_description ||
!media_description->has_codecs()) { continue;
} constauto type = media_description->type(); if (type == cricket::MEDIA_TYPE_AUDIO ||
type == cricket::MEDIA_TYPE_VIDEO) { for (constauto& c : media_description->codecs()) { auto error = FindDuplicateCodecParameters(
c.ToCodecParameters(), payload_to_codec_parameters); if (!error.ok()) { return error;
}
}
}
}
} return RTCError::OK();
}
RTCError FindDuplicateHeaderExtensionIds( const RtpExtension extension,
std::map<int, RtpExtension>& id_to_extension) { auto existing_extension = id_to_extension.find(extension.id); if (existing_extension != id_to_extension.end() &&
!(extension.uri == existing_extension->second.uri &&
extension.encrypt == existing_extension->second.encrypt)) {
LOG_AND_RETURN_ERROR(
RTCErrorType::INVALID_PARAMETER, "A BUNDLE group contains a codec collision for " "header extension id=" +
rtc::ToString(extension.id) + ". The id must be the same across all bundled media descriptions");
}
id_to_extension.insert(std::make_pair(extension.id, extension)); return RTCError::OK();
}
RTCError ValidateBundledRtpHeaderExtensions( const cricket::SessionDescription& description) { // https://www.rfc-editor.org/rfc/rfc8843#name-rtp-header-extensions-consi // ... the identifier used for a given extension MUST identify the same // extension across all the bundled media descriptions.
std::vector<const cricket::ContentGroup*> bundle_groups =
description.GetGroupsByName(cricket::GROUP_TYPE_BUNDLE); for (const cricket::ContentGroup* bundle_group : bundle_groups) {
std::map<int, RtpExtension> id_to_extension; for (const std::string& content_name : bundle_group->content_names()) { const ContentInfo* content_description =
description.GetContentByName(content_name); if (!content_description) {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, "A BUNDLE group contains a MID='" + content_name + "' matching no m= section.");
} const cricket::MediaContentDescription* media_description =
content_description->media_description();
RTC_DCHECK(media_description); if (content_description->rejected || !media_description ||
!media_description->has_codecs()) { continue;
}
for (constauto& extension : media_description->rtp_header_extensions()) { auto error =
FindDuplicateHeaderExtensionIds(extension, id_to_extension); if (!error.ok()) { return error;
}
}
}
} return RTCError::OK();
}
RTCError ValidateRtpHeaderExtensionsForSpecSimulcast( const cricket::SessionDescription& description) { for (const ContentInfo& content : description.contents()) { if (content.type != MediaProtocolType::kRtp || content.rejected) { continue;
} constauto media_description = content.media_description(); if (!media_description->HasSimulcast()) { continue;
} auto extensions = media_description->rtp_header_extensions(); auto it = absl::c_find_if(extensions, [](const RtpExtension& ext) { return ext.uri == RtpExtension::kRidUri;
}); if (it == extensions.end()) {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, "The media section with MID='" + content.mid() + "' negotiates simulcast but does not negotiate " "the RID RTP header extension.");
}
} return RTCError::OK();
}
RTCError ValidateSsrcGroups(const cricket::SessionDescription& description) { for (const ContentInfo& content : description.contents()) { if (content.type != MediaProtocolType::kRtp) { continue;
} for (const StreamParams& stream : content.media_description()->streams()) { for (const cricket::SsrcGroup& group : stream.ssrc_groups) { // Validate the number of SSRCs for standard SSRC group semantics such // as FID and FEC-FR and the non-standard SIM group. if ((group.semantics == cricket::kFidSsrcGroupSemantics &&
group.ssrcs.size() != 2) ||
(group.semantics == cricket::kFecFrSsrcGroupSemantics &&
group.ssrcs.size() != 2) ||
(group.semantics == cricket::kSimSsrcGroupSemantics &&
group.ssrcs.size() > kMaxSimulcastStreams)) {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, "The media section with MID='" + content.mid() + "' has a ssrc-group with semantics " +
group.semantics + " and an unexpected number of SSRCs.");
}
}
}
} return RTCError::OK();
}
RTCError ValidatePayloadTypes(const cricket::SessionDescription& description) { for (const ContentInfo& content : description.contents()) { if (content.type != MediaProtocolType::kRtp) { continue;
} constauto media_description = content.media_description();
RTC_DCHECK(media_description); if (content.rejected || !media_description ||
!media_description->has_codecs()) { continue;
} constauto type = media_description->type(); if (type == cricket::MEDIA_TYPE_AUDIO ||
type == cricket::MEDIA_TYPE_VIDEO) { for (constauto& codec : media_description->codecs()) { if (!cricket::UsedPayloadTypes::IsIdValid(
codec, media_description->rtcp_mux())) {
LOG_AND_RETURN_ERROR(
RTCErrorType::INVALID_PARAMETER, "The media section with MID='" + content.mid() + "' used an invalid payload type " + rtc::ToString(codec.id) + " for codec '" + codec.name + ", rtcp-mux:" +
(media_description->rtcp_mux() ? "enabled" : "disabled"));
}
}
}
} return RTCError::OK();
}
// 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).
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 (constauto& 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; // If a payload type has been specified for this rid, set the codec // corresponding to that payload type. auto rid_desc = std::find_if(
desc.receive_rids().begin(), desc.receive_rids().end(),
[&layer](const RidDescription& rid) { return rid.rid == layer.rid; }); if (rid_desc != desc.receive_rids().end() &&
!rid_desc->payload_types.empty()) { int payload_type = rid_desc->payload_types[0]; auto codec = std::find_if(desc.codecs().begin(), desc.codecs().end(),
[payload_type](const cricket::Codec& codec) { return codec.id == payload_type;
}); if (codec != desc.codecs().end()) {
parameters.codec = codec->ToCodecParameters();
}
}
result.push_back(parameters);
}
// 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->SetParametersInternalWithAllLayers(parameters); if (result.ok()) {
result = sender->DisableEncodingLayers(disabled_layers);
}
// The SDP parser used to populate these values by default for the 'content // name' if an a=mid line was absent.
absl::string_view GetDefaultMidForPlanB(cricket::MediaType media_type) { switch (media_type) { case cricket::MEDIA_TYPE_AUDIO: return cricket::CN_AUDIO; case cricket::MEDIA_TYPE_VIDEO: return cricket::CN_VIDEO; case cricket::MEDIA_TYPE_DATA: return cricket::CN_DATA; case cricket::MEDIA_TYPE_UNSUPPORTED: return"not supported";
}
RTC_DCHECK_NOTREACHED(); return"";
}
// Add options to |[audio/video]_media_description_options| from `senders`. void AddPlanBRtpSenderOptions( const std::vector<rtc::scoped_refptr<
RtpSenderProxyWithInternal<RtpSenderInternal>>>& senders,
cricket::MediaDescriptionOptions* audio_media_description_options,
cricket::MediaDescriptionOptions* video_media_description_options, int num_sim_layers) { for (constauto& sender : senders) { if (sender->media_type() == cricket::MEDIA_TYPE_AUDIO) { if (audio_media_description_options) {
audio_media_description_options->AddAudioSender(
sender->id(), sender->internal()->stream_ids());
}
} else {
RTC_DCHECK(sender->media_type() == cricket::MEDIA_TYPE_VIDEO); if (video_media_description_options) {
video_media_description_options->AddVideoSender(
sender->id(), sender->internal()->stream_ids(), {},
SimulcastLayerList(), num_sim_layers);
}
}
}
}
cricket::MediaDescriptionOptions GetMediaDescriptionOptionsForTransceiver(
RtpTransceiver* transceiver, const std::string& mid, bool is_create_offer) { // NOTE: a stopping transceiver should be treated as a stopped one in // createOffer as specified in // https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-createoffer. bool stopped =
is_create_offer ? transceiver->stopping() : transceiver->stopped();
cricket::MediaDescriptionOptions media_description_options(
transceiver->media_type(), mid, transceiver->direction(), stopped);
media_description_options.codec_preferences =
transceiver->codec_preferences();
media_description_options.header_extensions =
transceiver->GetHeaderExtensionsToNegotiate(); // This behavior is specified in JSEP. The gist is that: // 1. The MSID is included if the RtpTransceiver's direction is sendonly or // sendrecv. // 2. If the MSID is included, then it must be included in any subsequent // offer/answer exactly the same until the RtpTransceiver is stopped. if (stopped || (!RtpTransceiverDirectionHasSend(transceiver->direction()) &&
!transceiver->has_ever_been_used_to_send())) { return media_description_options;
}
// The following sets up RIDs and Simulcast. // RIDs are included if Simulcast is requested or if any RID was specified.
RtpParameters send_parameters =
transceiver->sender_internal()->GetParametersInternalWithAllLayers(); bool has_rids = std::any_of(send_parameters.encodings.begin(),
send_parameters.encodings.end(),
[](const RtpEncodingParameters& encoding) { return !encoding.rid.empty();
});
std::vector<RidDescription> send_rids;
SimulcastLayerList send_layers; for (const RtpEncodingParameters& encoding : send_parameters.encodings) { if (encoding.rid.empty()) { continue;
} auto send_rid = RidDescription(encoding.rid, RidDirection::kSend); if (encoding.codec) { auto send_codecs = transceiver->sender_internal()->GetSendCodecs(); for (const cricket::Codec& codec : send_codecs) { if (codec.MatchesRtpCodec(*encoding.codec)) {
send_rid.payload_types.push_back(codec.id); break;
}
}
}
send_rids.push_back(send_rid);
send_layers.AddLayer(SimulcastLayer(encoding.rid, !encoding.active));
}
if (has_rids) {
sender_options.rids = send_rids;
}
sender_options.simulcast_layers = send_layers; // When RIDs are configured, we must set num_sim_layers to 0 to. // Otherwise, num_sim_layers must be 1 because either there is no // simulcast, or simulcast is acheived by munging the SDP.
sender_options.num_sim_layers = has_rids ? 0 : 1;
media_description_options.sender_options.push_back(sender_options);
return media_description_options;
}
// Returns the ContentInfo at mline index `i`, or null if none exists. const ContentInfo* GetContentByIndex(const SessionDescriptionInterface* sdesc,
size_t i) { if (!sdesc) { return nullptr;
} const ContentInfos& contents = sdesc->description()->contents(); return (i < contents.size() ? &contents[i] : nullptr);
}
// From `rtc_options`, fill parts of `session_options` shared by all generated // m= sectionss (in other words, nothing that involves a map/array). void ExtractSharedMediaSessionOptions( const PeerConnectionInterface::RTCOfferAnswerOptions& rtc_options,
cricket::MediaSessionOptions* session_options) {
session_options->vad_enabled = rtc_options.voice_activity_detection;
session_options->bundle_enabled = rtc_options.use_rtp_mux;
session_options->raw_packetization_for_video =
rtc_options.raw_packetization_for_video;
}
// Generate a RTCP CNAME when a PeerConnection is created.
std::string GenerateRtcpCname() {
std::string cname; if (!rtc::CreateRandomString(kRtcpCnameLength, &cname)) {
RTC_LOG(LS_ERROR) << "Failed to generate CNAME.";
RTC_DCHECK_NOTREACHED();
} return cname;
}
// Check if we can send `new_stream` on a PeerConnection. bool CanAddLocalMediaStream(StreamCollectionInterface* current_streams,
MediaStreamInterface* new_stream) { if (!new_stream || !current_streams) { returnfalse;
} if (current_streams->find(new_stream->id()) != nullptr) {
RTC_LOG(LS_ERROR) << "MediaStream with ID " << new_stream->id()
<< " is already added."; returnfalse;
} returntrue;
}
rtc::scoped_refptr<DtlsTransport> LookupDtlsTransportByMid(
rtc::Thread* network_thread,
JsepTransportController* controller, const std::string& mid) { // TODO(tommi): Can we post this (and associated operations where this // function is called) to the network thread and avoid this BlockingCall? // We might be able to simplify a few things if we set the transport on // the network thread and then update the implementation to check that // the set_ and relevant get methods are always called on the network // thread (we'll need to update proxy maps). return network_thread->BlockingCall(
[controller, &mid] { return controller->LookupDtlsTransportByMid(mid); });
}
void UpdateRtpHeaderExtensionPreferencesFromSdpMunging( const cricket::SessionDescription* description,
TransceiverList* transceivers) { // This integrates the RTP Header Extension Control API and local SDP munging // for backward compability reasons. If something was enabled in the local // description via SDP munging, consider it non-stopped in the API as well // so that is shows up in subsequent offers/answers.
RTC_DCHECK(description);
RTC_DCHECK(transceivers); for (constauto& content : description->contents()) { auto transceiver = transceivers->FindByMid(content.name); if (!transceiver) { continue;
} auto extension_capabilities = transceiver->GetHeaderExtensionsToNegotiate(); // Set the capability of every extension we see here to "sendrecv". for (auto& ext : content.media_description()->rtp_header_extensions()) { auto it = absl::c_find_if(extension_capabilities,
[&ext](const RtpHeaderExtensionCapability c) { return ext.uri == c.uri;
}); if (it != extension_capabilities.end()) {
it->direction = RtpTransceiverDirection::kSendRecv;
}
}
transceiver->SetHeaderExtensionsToNegotiate(extension_capabilities);
}
}
// This class stores state related to a SetRemoteDescription operation, captures // and reports potential errors that might occur and makes sure to notify the // observer of the operation and the operations chain of completion. class SdpOfferAnswerHandler::RemoteDescriptionOperation { public:
RemoteDescriptionOperation(
SdpOfferAnswerHandler* handler,
std::unique_ptr<SessionDescriptionInterface> desc,
rtc::scoped_refptr<SetRemoteDescriptionObserverInterface> observer,
std::function<void()> operations_chain_callback)
: handler_(handler),
desc_(std::move(desc)),
observer_(std::move(observer)),
operations_chain_callback_(std::move(operations_chain_callback)),
unified_plan_(handler_->IsUnifiedPlan()) { if (!desc_) {
type_ = static_cast<SdpType>(-1);
InvalidParam("SessionDescription is NULL.");
} else {
type_ = desc_->GetType();
}
}
// Notifies the observer that the operation is complete and releases the // reference to the observer. void SignalCompletion() { if (!observer_) return;
observer_->OnSetRemoteDescriptionComplete(error_);
observer_ = nullptr; // Only fire the notification once.
}
// If a session error has occurred the PeerConnection is in a possibly // inconsistent state so fail right away. bool HaveSessionError() {
RTC_DCHECK(ok()); if (handler_->session_error() != SessionError::kNone)
InternalError(handler_->GetSessionErrorMsg()); return !ok();
}
// Returns true if the operation was a rollback operation. If this function // returns true, the caller should consider the operation complete. Otherwise // proceed to the next step. bool MaybeRollback() {
RTC_DCHECK_RUN_ON(handler_->signaling_thread());
RTC_DCHECK(ok()); if (type_ != SdpType::kRollback) { // Check if we can do an implicit rollback. if (type_ == SdpType::kOffer && unified_plan_ &&
handler_->pc_->configuration()->enable_implicit_rollback &&
handler_->signaling_state() ==
PeerConnectionInterface::kHaveLocalOffer) {
handler_->Rollback(type_);
} returnfalse;
}
if (unified_plan_) {
error_ = handler_->Rollback(type_);
} elseif (type_ == SdpType::kRollback) {
Unsupported("Rollback not supported in Plan B");
}
returntrue;
}
// Report to UMA the format of the received offer or answer. void ReportOfferAnswerUma() {
RTC_DCHECK(ok()); if (type_ == SdpType::kOffer || type_ == SdpType::kAnswer) {
handler_->pc_->ReportSdpBundleUsage(*desc_.get());
}
}
// Checks if the session description for the operation is valid. If not, the // function captures error information and returns false. Note that if the // return value is false, the operation should be considered done. bool IsDescriptionValid() {
RTC_DCHECK_RUN_ON(handler_->signaling_thread());
RTC_DCHECK(ok());
RTC_DCHECK(bundle_groups_by_mid_.empty()) << "Already called?";
bundle_groups_by_mid_ = GetBundleGroupsByMid(description());
error_ = handler_->ValidateSessionDescription(
desc_.get(), cricket::CS_REMOTE, bundle_groups_by_mid_); return ok();
}
// Transfers ownership of the session description object over to `handler_`. bool ReplaceRemoteDescriptionAndCheckError() {
RTC_DCHECK_RUN_ON(handler_->signaling_thread());
RTC_DCHECK(ok());
RTC_DCHECK(desc_);
RTC_DCHECK(!replaced_remote_description_); #if RTC_DCHECK_IS_ON constauto* existing_remote_description = handler_->remote_description(); #endif
if (ok()) { #if RTC_DCHECK_IS_ON // Sanity check that our `old_remote_description()` method always returns // the same value as `remote_description()` did before the call to // ReplaceRemoteDescription.
RTC_DCHECK_EQ(existing_remote_description, old_remote_description()); #endif
} else {
SetAsSessionError();
}
return ok();
}
bool UpdateChannels() {
RTC_DCHECK(ok());
RTC_DCHECK(!desc_) << "ReplaceRemoteDescription hasn't been called";
// Transport and Media channels will be created only when offer is set. if (unified_plan_) {
error_ = handler_->UpdateTransceiversAndDataChannels(
cricket::CS_REMOTE, *remote_description,
handler_->local_description(), old_remote_description(),
bundle_groups_by_mid_);
} 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.
error_ = handler_->CreateChannels(*session_desc);
} // Remove unused channels if MediaContentDescription is rejected.
handler_->RemoveUnusedChannels(session_desc);
}
const SessionDescriptionInterface* old_remote_description() const {
RTC_DCHECK(!desc_) << "Called before replacing the remote description"; if (type_ == SdpType::kAnswer) return replaced_remote_description_.get(); return replaced_remote_description_
? replaced_remote_description_.get()
: handler_->current_remote_description();
}
// Returns a reference to a cached map of bundle groups ordered by mid. // Note that this will only be valid after a successful call to // `IsDescriptionValid`. const std::map<std::string, const cricket::ContentGroup*>&
bundle_groups_by_mid() const {
RTC_DCHECK(ok()); return bundle_groups_by_mid_;
}
private: // Convenience methods for populating the embedded `error_` object. void Unsupported(std::string message) {
SetError(RTCErrorType::UNSUPPORTED_OPERATION, std::move(message));
}
// Called when the PeerConnection could be in an inconsistent state and we set // the session error so that future calls to // SetLocalDescription/SetRemoteDescription fail. void SetAsSessionError() {
RTC_DCHECK(!ok());
handler_->SetSessionError(SessionError::kContent, error_.message());
}
SdpOfferAnswerHandler* const handler_;
std::unique_ptr<SessionDescriptionInterface> desc_; // Keeps the replaced session description object alive while the operation // is taking place since methods that depend on `old_remote_description()` // for updating the state, need it.
std::unique_ptr<SessionDescriptionInterface> replaced_remote_description_;
rtc::scoped_refptr<SetRemoteDescriptionObserverInterface> observer_;
std::function<void()> operations_chain_callback_;
RTCError error_ = RTCError::OK();
std::map<std::string, const cricket::ContentGroup*> bundle_groups_by_mid_;
SdpType type_; constbool unified_plan_;
}; // 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_);
}
// 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_();
}
// 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 { #if RTC_DCHECK_IS_ON
RTC_DCHECK(was_called_); #endif
}
void OnSuccess(SessionDescriptionInterface* desc) override { #if RTC_DCHECK_IS_ON
RTC_DCHECK(!was_called_);
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);
}
// 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)) {}
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 SdpOfferAnswerHandler::Initialize( const PeerConnectionInterface::RTCConfiguration& configuration,
PeerConnectionDependencies& dependencies,
ConnectionContext* context,
PayloadTypeSuggester* pt_suggester) {
RTC_DCHECK_RUN_ON(signaling_thread()); // 100 kbps is used by default, but can be overriden by a non-standard // RTCConfiguration value (not available on Web).
video_options_.screencast_min_bitrate_kbps =
configuration.screencast_min_bitrate.value_or(100);
// Obtain a certificate from RTCConfiguration if any were provided (optional).
rtc::scoped_refptr<rtc::RTCCertificate> certificate; if (!configuration.certificates.empty()) { // TODO(hbos,torbjorng): Decide on certificate-selection strategy instead of // just picking the first one. The decision should be made based on the DTLS // handshake. The DTLS negotiations need to know about all certificates.
certificate = configuration.certificates[0];
}
if (pc_->options()->disable_encryption) {
RTC_LOG(LS_INFO)
<< "Disabling encryption. This should only be done in tests.";
webrtc_session_desc_factory_->SetInsecureForTesting();
}
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. auto observer_wrapper = rtc::make_ref_counted<
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::make_ref_counted<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(
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. auto create_sdp_observer =
rtc::make_ref_counted<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;
}
});
}
// Invalidate the stats caches to make sure that they get // updated the next time getStats() gets called, as updating the session // description affects the stats.
pc_->ClearStatsCache();
// 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);
} if (!initial_offerer_) {
initial_offerer_.emplace(type == SdpType::kOffer);
} // The session description to apply now must be accessed by // `local_description()`.
RTC_DCHECK(local_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;
}
}
if (IsUnifiedPlan()) {
error = UpdateTransceiversAndDataChannels(
cricket::CS_LOCAL, *local_description(), old_local_description,
remote_description(), bundle_groups_by_mid); if (!error.ok()) {
RTC_LOG(LS_ERROR) << error.message() << " (" << SdpTypeToString(type)
<< ")"; return error;
} if (ConfiguredForMedia()) {
std::vector<rtc::scoped_refptr<RtpTransceiverInterface>> remove_list;
std::vector<rtc::scoped_refptr<MediaStreamInterface>> removed_streams; for (constauto& transceiver_ext : transceivers()->List()) { auto transceiver = transceiver_ext->internal(); 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 = LookupDtlsTransportByMid(
context_->network_thread(), transport_controller_s(),
*transceiver->mid());
transceiver->sender_internal()->set_transport(dtls_transport);
transceiver->receiver_internal()->set_transport(dtls_transport);
}
const ContentInfo* content =
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->fired_direction() &&
RtpTransceiverDirectionHasRecv(
*transceiver->fired_direction()))) {
ProcessRemovalOfRemoteTrack(transceiver_ext, &remove_list,
&removed_streams);
} // 2.2.7.1.6.2: Set transceiver's [[CurrentDirection]] and // [[FiredDirection]] slots to direction.
transceiver->set_current_direction(media_desc->direction());
transceiver->set_fired_direction(media_desc->direction());
}
} auto observer = pc_->Observer(); for (constauto& transceiver : remove_list) {
observer->OnRemoveTrack(transceiver->receiver());
} for (constauto& 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.
error = CreateChannels(*local_description()->description()); if (!error.ok()) {
RTC_LOG(LS_ERROR) << error.message() << " (" << SdpTypeToString(type)
<< ")"; return error;
}
} // Remove unused channels if MediaContentDescription is rejected.
RemoveUnusedChannels(local_description()->description());
}
// Now that we have a local description, we can push down remote candidates.
UseCandidatesInRemoteDescription();
pending_ice_restarts_.clear(); if (session_error() != SessionError::kNone) {
LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR, GetSessionErrorMsg());
}
// If setting the description decided our SSL role, allocate any necessary // SCTP sids.
AllocateSctpSids();
// Validate SSRCs, we do not allow duplicates. if (ConfiguredForMedia()) {
std::set<uint32_t> used_ssrcs; for (constauto& content : local_description()->description()->contents()) { for (constauto& stream : content.media_description()->streams()) { for (uint32_t ssrc : stream.ssrcs) { auto result = used_ssrcs.insert(ssrc); if (!result.second) {
LOG_AND_RETURN_ERROR(
RTCErrorType::INVALID_PARAMETER, "Duplicate ssrc " + rtc::ToString(ssrc) + " is not allowed");
}
}
}
}
}
if (IsUnifiedPlan()) { if (ConfiguredForMedia()) { // We must use List and not ListInternal here because // transceivers()->StableState() is indexed by the non-internal refptr. for (constauto& transceiver_ext : transceivers()->List()) { auto transceiver = transceiver_ext->internal(); if (transceiver->stopped()) { continue;
} const ContentInfo* content =
FindMediaSectionForTransceiver(transceiver, local_description()); if (!content) { continue;
}
cricket::ChannelInterface* channel = transceiver->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->sender_internal()->SetSsrc(0);
} else { // Get the StreamParams from the channel which could generate SSRCs. const std::vector<StreamParams>& streams = channel->local_streams();
transceiver->sender_internal()->set_stream_ids(
streams[0].stream_ids()); auto encodings =
transceiver->sender_internal()->init_send_encodings();
transceiver->sender_internal()->SetSsrc(streams[0].first_ssrc()); if (!encodings.empty()) {
transceivers()
->StableState(transceiver_ext)
->SetInitSendEncodings(encodings);
}
}
}
}
} 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) {
RemoveSenders(cricket::MEDIA_TYPE_AUDIO);
} else { const cricket::MediaContentDescription* audio_desc =
audio_content->media_description();
UpdateLocalSenders(audio_desc->streams(), audio_desc->type());
}
}
if (type == SdpType::kAnswer &&
local_ice_credentials_to_replace_->SatisfiesIceRestart(
*current_local_description_)) {
local_ice_credentials_to_replace_->ClearIceCredentials();
}
if (IsUnifiedPlan()) {
UpdateRtpHeaderExtensionPreferencesFromSdpMunging(
local_description()->description(), transceivers());
}
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::make_unique<RemoteDescriptionOperation>(
this_weak_ptr.get(), std::move(desc),
rtc::make_ref_counted<SetSessionDescriptionObserverAdapter>(
this_weak_ptr, observer_refptr),
std::move(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 { if (!observer) {
RTC_DLOG(LS_ERROR) << "SetRemoteDescription - observer is NULL.";
operations_chain_callback(); return;
}
// 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;
}
// The session description to apply now must be accessed by // `remote_description()`. const cricket::SessionDescription* session_desc =
remote_description()->description();
constauto* local = local_description();
// NOTE: This will perform a BlockingCall() to the network thread. return transport_controller_s()->SetRemoteDescription(
sdp_type, local ? local->description() : nullptr, session_desc);
}
// Invalidate the stats caches to make sure that they get // updated next time getStats() gets called, as updating the session // description affects the stats.
pc_->ClearStatsCache();
if (!operation->ReplaceRemoteDescriptionAndCheckError()) return;
if (!operation->UpdateChannels()) return;
// NOTE: Candidates allocation will be initiated only when // SetLocalDescription is called. if (!operation->UpdateSessionState()) return;
if (!operation->UseCandidatesInRemoteDescription()) return;
if (operation->old_remote_description()) { for (const cricket::ContentInfo& content :
operation->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(operation->old_remote_description(),
remote_description(), content.name)) { if (operation->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(
operation->old_remote_description(), content.name,
mutable_remote_description());
}
}
}
if (operation->HaveSessionError()) return;
// 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_internal() ==
PeerConnectionInterface::kIceConnectionNew) {
pc_->SetIceConnectionState(PeerConnectionInterface::kIceConnectionChecking);
}
// If setting the description decided our SSL role, allocate any necessary // SCTP sids.
AllocateSctpSids();
if (operation->unified_plan()) {
ApplyRemoteDescriptionUpdateTransceiverState(operation->type());
}
remote_peer_supports_msid_ =
remote_description()->description()->msid_signaling() !=
cricket::kMsidSignalingNotUsed;
if (!operation->unified_plan()) {
PlanBUpdateSendersAndReceivers(
GetFirstAudioContent(remote_description()->description()),
GetFirstAudioContentDescription(remote_description()->description()),
GetFirstVideoContent(remote_description()->description()),
GetFirstVideoContentDescription(remote_description()->description()));
}
if (operation->type() == SdpType::kAnswer) { if (local_ice_credentials_to_replace_->SatisfiesIceRestart(
*current_local_description_)) {
local_ice_credentials_to_replace_->ClearIceCredentials();
}
RemoveStoppedTransceivers();
}
// Consider the operation complete at this point.
operation->SignalCompletion();
void SdpOfferAnswerHandler::ApplyRemoteDescriptionUpdateTransceiverState(
SdpType sdp_type) {
RTC_DCHECK_RUN_ON(signaling_thread());
RTC_DCHECK(IsUnifiedPlan()); if (!ConfiguredForMedia()) { return;
}
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 (constauto& transceiver_ext : transceivers()->List()) { constauto transceiver = transceiver_ext->internal(); const ContentInfo* content =
FindMediaSectionForTransceiver(transceiver, remote_description()); if (!content) { continue;
} const MediaContentDescription* media_desc = content->media_description();
RtpTransceiverDirection local_direction =
RtpTransceiverDirectionReversed(media_desc->direction()); // Remember the previous remote streams if this is a remote offer. This // makes it possible to rollback modifications to the streams. if (sdp_type == SdpType::kOffer) {
transceivers()
->StableState(transceiver_ext)
->SetRemoteStreamIds(transceiver->receiver()->stream_ids());
} // 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();
}
RTC_LOG(LS_INFO) << "Processing the MSIDs for MID=" << content->name
<< " (" << GetStreamIdsString(stream_ids) << ").";
SetAssociatedRemoteStreams(transceiver->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 << "."; // Since the transceiver is passed to the user in an // OnTrack event, we must use the proxied transceiver.
now_receiving_transceivers.push_back(transceiver_ext);
}
} // 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()))) {
ProcessRemovalOfRemoteTrack(transceiver_ext, &remove_list,
&removed_streams);
} // 2.2.8.1.10: Set transceiver's [[FiredDirection]] slot to direction. if (sdp_type == SdpType::kOffer) { // Remember the previous fired direction if this is a remote offer. This // makes it possible to rollback modifications to [[FiredDirection]], // which is necessary for "ontrack" to fire in or after rollback.
transceivers()
->StableState(transceiver_ext)
->SetFiredDirection(transceiver->fired_direction());
}
transceiver->set_fired_direction(local_direction); // 2.2.8.1.11: If description is of type "answer" or "pranswer", then run // the following steps: if (sdp_type == SdpType::kPrAnswer || sdp_type == SdpType::kAnswer) { // 2.2.8.1.11.1: Set transceiver's [[CurrentDirection]] slot to // direction.
transceiver->set_current_direction(local_direction); // 2.2.8.1.11.[3-6]: Set the transport internal slots. if (transceiver->mid()) { auto dtls_transport = LookupDtlsTransportByMid(
context_->network_thread(), transport_controller_s(),
*transceiver->mid());
transceiver->sender_internal()->set_transport(dtls_transport);
transceiver->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->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->receiver_internal()->SetupMediaChannel(ssrc);
} else {
transceiver->receiver_internal()->SetupUnsignaledMediaChannel();
}
}
} // Once all processing has finished, fire off callbacks. auto observer = pc_->Observer(); for (constauto& transceiver : now_receiving_transceivers) {
pc_->legacy_stats()->AddTrack(transceiver->receiver()->track().get());
observer->OnTrack(transceiver);
observer->OnAddTrack(transceiver->receiver(),
transceiver->receiver()->streams());
} for (constauto& stream : added_streams) {
observer->OnAddStream(stream);
} for (constauto& transceiver : remove_list) {
observer->OnRemoveTrack(transceiver->receiver());
} for (constauto& stream : removed_streams) {
observer->OnRemoveStream(stream);
}
}
// 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());
// 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) {
RemoveSenders(cricket::MEDIA_TYPE_AUDIO);
} else { bool default_audio_track_needed =
!remote_peer_supports_msid_ &&
RtpTransceiverDirectionHasSend(audio_desc->direction());
UpdateRemoteSendersList(GetActiveStreams(audio_desc),
default_audio_track_needed, audio_desc->type(),
new_streams.get());
}
}
// Find all video rtp streams and create corresponding remote VideoTracks // and MediaStreams. if (video_content) { if (video_content->rejected) {
RemoveSenders(cricket::MEDIA_TYPE_VIDEO);
} else { bool default_video_track_needed =
!remote_peer_supports_msid_ &&
RtpTransceiverDirectionHasSend(video_desc->direction());
UpdateRemoteSendersList(GetActiveStreams(video_desc),
default_video_track_needed, video_desc->type(),
new_streams.get());
}
}
// 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_->legacy_stats()->AddStream(new_stream);
observer->OnAddStream(rtc::scoped_refptr<MediaStreamInterface>(new_stream));
}
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 (session_error() != SessionError::kNone) {
std::string error_message = 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;
}
// 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), bundle_groups_by_mid); // `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.
SetSessionError(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) {
RemoveStoppedTransceivers();
// TODO(deadbeef): We already had to hop to the network thread for // MaybeStartGathering...
context_->network_thread()->BlockingCall(
[this] { port_allocator()->DiscardCandidatePool(); });
}
// 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.
transport_controller_s()->MaybeStartGathering();
}
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_->message_handler()->PostCreateSessionDescriptionFailure(
observer.get(),
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 (session_error() != SessionError::kNone) {
std::string error_message = GetSessionErrorMsg();
RTC_LOG(LS_ERROR) << "CreateOffer: " << error_message;
pc_->message_handler()->PostCreateSessionDescriptionFailure(
observer.get(),
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_->message_handler()->PostCreateSessionDescriptionFailure(
observer.get(),
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 = HandleLegacyOfferOptions(options); if (!error.ok()) {
pc_->message_handler()->PostCreateSessionDescriptionFailure(
observer.get(), std::move(error)); return;
}
}
void SdpOfferAnswerHandler::CreateAnswer(
CreateSessionDescriptionObserver* observer, const PeerConnectionInterface::RTCOfferAnswerOptions& options) {
TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::CreateAnswer");
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. auto observer_wrapper = rtc::make_ref_counted<
CreateSessionDescriptionObserverOperationWrapper>(
std::move(observer_refptr), std::move(operations_chain_callback));
this_weak_ptr->DoCreateAnswer(options, observer_wrapper);
});
}
// If a session error has occurred the PeerConnection is in a possibly // inconsistent state so fail right away. if (session_error() != SessionError::kNone) {
std::string error_message = GetSessionErrorMsg();
RTC_LOG(LS_ERROR) << "CreateAnswer: " << error_message;
pc_->message_handler()->PostCreateSessionDescriptionFailure(
observer.get(),
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_->message_handler()->PostCreateSessionDescriptionFailure(
observer.get(),
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.";
}
}
// Handle remote descriptions missing a=mid lines for interop with legacy // end points.
FillInMissingRemoteMids(operation->description()); if (!operation->IsDescriptionValid()) return;
ApplyRemoteDescription(std::move(operation));
}
// Called after a DoSetRemoteDescription operation completes. void SdpOfferAnswerHandler::SetRemoteDescriptionPostProcess(bool was_answer) {
RTC_DCHECK(remote_description());
if (was_answer) { // TODO(deadbeef): We already had to hop to the network thread for // MaybeStartGathering...
context_->network_thread()->BlockingCall(
[this] { port_allocator()->DiscardCandidatePool(); });
}
// 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(
remote_streams_->find(stream_id)); if (!stream) {
stream = MediaStreamProxy::Create(rtc::Thread::Current(),
MediaStream::Create(stream_id));
remote_streams_->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);
RemoveRemoteStreamsIfEmpty(previous_streams, removed_streams);
}
bool SdpOfferAnswerHandler::AddIceCandidate( const IceCandidateInterface* ice_candidate) { const AddIceCandidateResult result = AddIceCandidateInternal(ice_candidate);
NoteAddIceCandidateResult(result); // If the return value is kAddIceCandidateFailNotReady, the candidate has // been added, although not 'ready', but that's a success. return result == kAddIceCandidateSuccess ||
result == kAddIceCandidateFailNotReady;
}
// Add this candidate to the remote session description. if (!mutable_remote_description()->AddCandidate(ice_candidate)) {
RTC_LOG(LS_ERROR) << "AddIceCandidate: Candidate cannot be used."; return kAddIceCandidateFailInAddition;
}
if (!ready) {
RTC_LOG(LS_INFO) << "AddIceCandidate: Not ready to use candidate."; return kAddIceCandidateFailNotReady;
}
if (!UseCandidate(ice_candidate)) { return kAddIceCandidateFailNotUsable;
}
void SdpOfferAnswerHandler::AddIceCandidate(
std::unique_ptr<IceCandidateInterface> candidate,
std::function<void(RTCError)> callback) {
TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::AddIceCandidate");
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) { auto result =
this_weak_ptr
? this_weak_ptr->AddIceCandidateInternal(candidate.get())
: kAddIceCandidateFailClosed;
NoteAddIceCandidateResult(result);
operations_chain_callback(); switch (result) { case AddIceCandidateResult::kAddIceCandidateSuccess: case AddIceCandidateResult::kAddIceCandidateFailNotReady: // Success!
callback(RTCError::OK()); break; case AddIceCandidateResult::kAddIceCandidateFailClosed: // Note that the spec says to just abort without resolving the // promise in this case, but this layer must return an RTCError.
callback(RTCError(
RTCErrorType::INVALID_STATE, "AddIceCandidate failed because the session was shut down")); break; case AddIceCandidateResult::kAddIceCandidateFailNoRemoteDescription: // Spec: "If remoteDescription is null return a promise rejected // with a newly created InvalidStateError."
callback(RTCError(RTCErrorType::INVALID_STATE, "The remote description was null")); break; case AddIceCandidateResult::kAddIceCandidateFailNullCandidate: // TODO(https://crbug.com/935898): Handle end-of-candidates instead // of treating null candidate as an error.
callback(RTCError(RTCErrorType::UNSUPPORTED_OPERATION, "Error processing ICE candidate")); break; case AddIceCandidateResult::kAddIceCandidateFailNotValid: case AddIceCandidateResult::kAddIceCandidateFailInAddition: case AddIceCandidateResult::kAddIceCandidateFailNotUsable: // Spec: "If candidate could not be successfully added [...] Reject // p with a newly created OperationError and abort these steps." // UNSUPPORTED_OPERATION maps to OperationError.
callback(RTCError(RTCErrorType::UNSUPPORTED_OPERATION, "Error processing ICE candidate")); break; default:
RTC_DCHECK_NOTREACHED();
}
});
}
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."; returnfalse;
}
if (!remote_description()) {
RTC_LOG(LS_ERROR) << "RemoveIceCandidates: ICE candidates can't be removed " "without any remote session description."; returnfalse;
}
if (candidates.empty()) {
RTC_LOG(LS_ERROR) << "RemoveIceCandidates: candidates are empty."; returnfalse;
}
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 = transport_controller_s()->RemoveRemoteCandidates(candidates); if (!error.ok()) {
RTC_LOG(LS_ERROR)
<< "RemoveIceCandidates: Error when removing remote candidates: "
<< error.message();
} returntrue;
}
// 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(session_error() == SessionError::kNone);
// If this is answer-ish we're ready to let media flow. if (type == SdpType::kPrAnswer || type == SdpType::kAnswer) {
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);
} elseif (type == SdpType::kPrAnswer) {
ChangeSignalingState(source == cricket::CS_LOCAL
? PeerConnectionInterface::kHaveLocalPrAnswer
: PeerConnectionInterface::kHaveRemotePrAnswer);
} else {
RTC_DCHECK(type == SdpType::kAnswer);
ChangeSignalingState(PeerConnectionInterface::kStable); if (ConfiguredForMedia()) {
transceivers()->DiscardStableStates();
}
}
// Update internal objects according to the session description's media // descriptions. return PushdownMediaDescription(type, source, bundle_groups_by_mid);
}
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()) { returntrue;
} // 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_) { returnfalse;
} // 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; returnfalse;
} // 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) { returnfalse;
} // All checks have passed - please fire "negotiationneeded" now! returntrue;
}
rtc::scoped_refptr<StreamCollectionInterface>
SdpOfferAnswerHandler::local_streams() {
RTC_DCHECK_RUN_ON(signaling_thread());
RTC_CHECK(!IsUnifiedPlan()) << "local_streams is not available with Unified " "Plan SdpSemantics. Please use GetSenders " "instead."; return local_streams_;
}
rtc::scoped_refptr<StreamCollectionInterface>
SdpOfferAnswerHandler::remote_streams() {
RTC_DCHECK_RUN_ON(signaling_thread());
RTC_CHECK(!IsUnifiedPlan()) << "remote_streams is not available with Unified " "Plan SdpSemantics. Please use GetReceivers " "instead."; return remote_streams_;
}
bool SdpOfferAnswerHandler::AddStream(MediaStreamInterface* local_stream) {
RTC_DCHECK_RUN_ON(signaling_thread());
RTC_CHECK(!IsUnifiedPlan()) << "AddStream is not available with Unified Plan " "SdpSemantics. Please use AddTrack instead."; if (pc_->IsClosed()) { returnfalse;
} if (!CanAddLocalMediaStream(local_streams_.get(), local_stream)) { returnfalse;
}
RTCError SdpOfferAnswerHandler::Rollback(SdpType desc_type) {
TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::Rollback"); auto state = signaling_state(); if (state != PeerConnectionInterface::kHaveLocalOffer &&
state != PeerConnectionInterface::kHaveRemoteOffer) {
LOG_AND_RETURN_ERROR(
RTCErrorType::INVALID_STATE,
(rtc::StringBuilder("Called in wrong signalingState: ")
<< (PeerConnectionInterface::AsString(signaling_state())))
.Release());
}
RTC_DCHECK_RUN_ON(signaling_thread());
RTC_DCHECK(IsUnifiedPlan());
std::vector<rtc::scoped_refptr<RtpTransceiverInterface>>
now_receiving_transceivers;
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 : transceivers()->StableStates()) { auto transceiver = transceivers_stable_state_pair.first; auto state = transceivers_stable_state_pair.second;
if (state.did_set_fired_direction()) { // If this rollback triggers going from not receiving to receving again, // we need to fire "ontrack". bool previously_fired_direction_is_recv =
transceiver->fired_direction().has_value() &&
RtpTransceiverDirectionHasRecv(*transceiver->fired_direction()); bool currently_fired_direction_is_recv =
state.fired_direction().has_value() &&
RtpTransceiverDirectionHasRecv(state.fired_direction().value()); if (!previously_fired_direction_is_recv &&
currently_fired_direction_is_recv) {
now_receiving_transceivers.push_back(transceiver);
}
transceiver->internal()->set_fired_direction(state.fired_direction());
}
// Due to the above `continue` statement, the below code only runs if there // is a change in mid association (has_m_section), if the transceiver was // newly created (newly_created) or if remote streams were not set.
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 {
transceiver->internal()->StopTransceiverProcedure();
transceivers()->Remove(transceiver);
}
} if (state.init_send_encodings()) {
transceiver->internal()->sender_internal()->set_init_send_encodings(
state.init_send_encodings().value());
}
transceiver->internal()->sender_internal()->set_transport(nullptr);
transceiver->internal()->receiver_internal()->set_transport(nullptr); if (state.has_m_section()) {
transceiver->internal()->set_mid(state.mid());
transceiver->internal()->set_mline_index(state.mline_index());
}
}
RTCError e = transport_controller_s()->RollbackTransports(); if (!e.ok()) { return e;
}
transceivers()->DiscardStableStates();
pending_local_description_.reset();
pending_remote_description_.reset();
ChangeSignalingState(PeerConnectionInterface::kStable);
// Once all processing has finished, fire off callbacks. for (constauto& transceiver : now_receiving_transceivers) {
pc_->Observer()->OnTrack(transceiver);
pc_->Observer()->OnAddTrack(transceiver->receiver(),
transceiver->receiver()->streams());
} for (constauto& receiver : removed_receivers) {
pc_->Observer()->OnRemoveTrack(receiver);
} for (constauto& stream : all_added_streams) {
pc_->Observer()->OnAddStream(stream);
} for (constauto& 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();
}
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();
}
}
// 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();
}
void SdpOfferAnswerHandler::AllocateSctpSids() {
RTC_DCHECK_RUN_ON(signaling_thread()); if (!local_description() || !remote_description()) {
RTC_DLOG(LS_VERBOSE)
<< "Local and Remote descriptions must be applied to get the " "SSL Role of the SCTP transport."; return;
}
std::optional<rtc::SSLRole> guessed_role = GuessSslRole();
network_thread()->BlockingCall(
[&, data_channel_controller = data_channel_controller()] {
RTC_DCHECK_RUN_ON(network_thread());
std::optional<rtc::SSLRole> role = pc_->GetSctpSslRole_n(); if (!role)
role = guessed_role; if (role)
data_channel_controller->AllocateSctpSids(*role);
});
}
std::optional<rtc::SSLRole> SdpOfferAnswerHandler::GuessSslRole() const {
RTC_DCHECK_RUN_ON(signaling_thread()); if (!pc_->sctp_mid()) return std::nullopt;
// TODO(bugs.webrtc.org/13668): This guesswork is guessing wrong (returning // SSL_CLIENT = ACTIVE) if remote offer has role ACTIVE, but we'll be able // to detect that by looking at the SDP. // // The phases of establishing an SCTP session are: // // Offerer: // // * Before negotiation: Neither is_caller nor sctp_mid exists. // * After setting an offer as local description: is_caller is known (true), // sctp_mid is known, but we don't know the SSL role for sure (or if we'll // eventually get an SCTP session). // * After setting an answer as the remote description: We know is_caller, // sctp_mid and that we'll get the SCTP channel established (m-section // wasn't rejected). // * Special case: The SCTP m-section was rejected: Close datachannels. // * We MAY know the SSL role if we offered actpass and got back active or // passive; if the other end is a webrtc implementation, it will be active. // * After the TLS handshake: We have a definitive answer on the SSL role. // // Answerer: // // * After setting an offer as remote description: We know is_caller (false). // * If there was an SCTP session, we know the SCTP mid. We also know the // SSL role, since if the remote offer was actpass or passive, we'll answer // active, and if the remote offer was active, we're passive. // * Special case: No SCTP m= line. We don't know for sure if the remote // doesn't support it or just didn't offer it. Not sure what we do in this // case (logic would suggest fire a `negotiationneeded` event and generate a // subsequent offer, but this needs to be tested). // * After the TLS handshake: We know that TLS obeyed the protocol. There // should be an error surfaced somewhere if it didn't. // * "Guessing" should always be correct if we get an SCTP session and are not // the offerer.
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()) { returntrue;
}
// 3. Let description be connection.[[CurrentLocalDescription]]. const SessionDescriptionInterface* description = current_local_description(); if (!description) returntrue;
// 4. If connection has created any RTCDataChannels, and no m= section in // description has been negotiated yet for data, return true. if (data_channel_controller()->HasUsedDataChannels()) { const cricket::ContentInfo* data_content =
cricket::GetFirstDataContent(description->description()->contents()); if (!data_content) { returntrue;
} // The remote end might have rejected the data content. const cricket::ContentInfo* remote_data_content =
current_remote_description()
? current_remote_description()->description()->GetContentByName(
data_content->name)
: nullptr; if (remote_data_content && remote_data_content->rejected) { returntrue;
}
} if (!ConfiguredForMedia()) { returnfalse;
}
// 5. For each transceiver in connection's set of transceivers, perform the // following checks: for (constauto& transceiver : transceivers()->ListInternal()) { const ContentInfo* current_local_msection =
FindTransceiverMSection(transceiver, 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)) { returntrue;
} continue;
}
// 5.1 If transceiver.[[Stopping]] is true and transceiver.[[Stopped]] is // false, return true. if (transceiver->stopping() && !transceiver->stopped()) returntrue;
// 5.2 If transceiver isn't stopped and isn't yet associated with an m= // section in description, return true. if (!current_local_msection) returntrue;
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) returntrue;
std::vector<std::string> msection_msids; for (constauto& 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()) returntrue;
absl::c_sort(transceiver_msids);
absl::c_sort(msection_msids); if (transceiver_msids != msection_msids) returntrue;
}
// 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()) returntrue;
// 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()) returntrue;
if (current_local_media_description->direction() !=
(RtpTransceiverDirectionIntersection(
transceiver->direction(),
RtpTransceiverDirectionReversed(offered_direction)))) { returntrue;
}
}
} // If all the preceding checks were performed and true was not returned, // nothing remains to be negotiated; return false. returnfalse;
}
RTCError SdpOfferAnswerHandler::ValidateSessionDescription( const SessionDescriptionInterface* sdesc,
cricket::ContentSource source, const std::map<std::string, const cricket::ContentGroup*>&
bundle_groups_by_mid) { // An assumption is that a check for session error is done at a higher level.
RTC_DCHECK_EQ(SessionError::kNone, session_error());
if (!sdesc || !sdesc->description()) {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, kInvalidSdp);
}
SdpType type = sdesc->GetType(); if ((source == cricket::CS_LOCAL && !ExpectSetLocalDescription(type)) ||
(source == cricket::CS_REMOTE && !ExpectSetRemoteDescription(type))) {
LOG_AND_RETURN_ERROR(
RTCErrorType::INVALID_STATE,
(rtc::StringBuilder("Called in wrong state: ")
<< PeerConnectionInterface::AsString(signaling_state()))
.Release());
}
RTCError error = ValidateMids(*sdesc->description()); if (!error.ok()) { return error;
}
// Verify ice-ufrag and ice-pwd. if (!VerifyIceUfragPwdPresent(sdesc->description(), bundle_groups_by_mid)) {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER,
kSdpWithoutIceUfragPwd);
}
// Validate that there are no collisions of bundled payload types.
error = ValidateBundledPayloadTypes(*sdesc->description()); // TODO(bugs.webrtc.org/14420): actually reject.
RTC_HISTOGRAM_BOOLEAN("WebRTC.PeerConnection.ValidBundledPayloadTypes",
error.ok());
// Validate that there are no collisions of bundled header extensions ids.
error = ValidateBundledRtpHeaderExtensions(*sdesc->description()); if (!error.ok()) { return error;
}
// Validate the SSRC groups.
error = ValidateSsrcGroups(*sdesc->description()); if (!error.ok()) { return error;
}
if (!pc_->ValidateBundleSettings(sdesc->description(),
bundle_groups_by_mid)) {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER,
kBundleWithoutRtcpMux);
}
error = ValidatePayloadTypes(*sdesc->description()); if (!error.ok()) { return error;
}
// 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();
}
} elseif (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.");
}
} // Validate spec-simulcast which only works if the remote end negotiated the // mid and rid header extension.
error = ValidateRtpHeaderExtensionsForSpecSimulcast(*sdesc->description()); if (!error.ok()) { return error;
}
}
if (new_session.GetType() == SdpType::kOffer) { // If the BUNDLE policy is max-bundle, then we know for sure that all // transports will be bundled from the start. Return an error if // max-bundle is specified but the session description does not have a // BUNDLE group. if (pc_->configuration()->bundle_policy ==
PeerConnectionInterface::kBundlePolicyMaxBundle &&
bundle_groups_by_mid.empty()) {
LOG_AND_RETURN_ERROR(
RTCErrorType::INVALID_PARAMETER, "max-bundle configured but session description has no BUNDLE group");
}
}
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();
mid_generator_.AddKnownId(new_content.name); auto it = bundle_groups_by_mid.find(new_content.name); const cricket::ContentGroup* bundle_group =
it != bundle_groups_by_mid.end() ? it->second : nullptr; 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];
} auto transceiver_or_error =
AssociateTransceiver(source, new_session.GetType(), i, new_content,
old_local_content, old_remote_content); if (!transceiver_or_error.ok()) { // In the case where a transceiver is rejected locally prior to being // associated, we don't expect to find a transceiver, but might find it // in the case where state is still "stopping", not "stopped". if (new_content.rejected) { continue;
} return transceiver_or_error.MoveError();
} auto transceiver = transceiver_or_error.MoveValue();
RTCError error =
UpdateTransceiverChannel(transceiver, new_content, bundle_group); // Handle locally rejected content. This code path is only needed for apps // that SDP munge. Remote rejected content is handled in // ApplyRemoteDescriptionUpdateTransceiverState(). if (source == cricket::ContentSource::CS_LOCAL && new_content.rejected) { // Local offer. if (new_session.GetType() == SdpType::kOffer) { // If the RtpTransceiver API was used, it would already have made the // transceiver stopping. But if the rejection was caused by SDP // munging then we need to ensure the transceiver is stopping here. if (!transceiver->internal()->stopping()) {
transceiver->internal()->StopStandard();
}
RTC_DCHECK(transceiver->internal()->stopping());
} else { // Local answer.
RTC_DCHECK(new_session.GetType() == SdpType::kAnswer ||
new_session.GetType() == SdpType::kPrAnswer); // When RtpTransceiver API is used, rejection happens in the offer and // the transceiver will already be stopped at local answer time // (calling stop between SRD(offer) and SLD(answer) would not reject // the content in the answer - instead this would trigger a follow-up // O/A exchange). So if the content was rejected but the transceiver // is not already stopped, SDP munging has happened and we need to // ensure the transceiver is stopped. if (!transceiver->internal()->stopped()) {
transceiver->internal()->StopTransceiverProcedure();
}
RTC_DCHECK(transceiver->internal()->stopped());
}
} if (!error.ok()) { return error;
}
} elseif (media_type == cricket::MEDIA_TYPE_DATA) { constauto data_mid = pc_->sctp_mid(); if (data_mid && new_content.name != data_mid.value()) { // Ignore all but the first data section.
RTC_LOG(LS_INFO) << "Ignoring data media section with MID="
<< new_content.name; continue;
}
RTCError error =
UpdateDataChannelTransport(source, new_content, bundle_group); if (!error.ok()) { return error;
}
} elseif (media_type == cricket::MEDIA_TYPE_UNSUPPORTED) {
RTC_LOG(LS_INFO) << "Ignoring unsupported media type";
} 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) {
TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::AssociateTransceiver");
RTC_DCHECK(IsUnifiedPlan()); #if RTC_DCHECK_IS_ON // 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 = transceivers()->FindByMid(old_mid); // The transceiver should be disassociated in RemoveStoppedTransceivers()
RTC_DCHECK(!old_transceiver);
} #endif
const MediaContentDescription* media_desc = content.media_description(); auto transceiver = transceivers()->FindByMid(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 = transceivers()->FindByMLineIndex(mline_index);
} if (!transceiver) { // This may happen normally when media sections are rejected.
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, "Transceiver not found based on m-line index");
}
} 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 = 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 = rtp_manager()->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 =
rtp_manager()->CreateReceiver(media_desc->type(), receiver_id);
transceiver = rtp_manager()->CreateAndAddTransceiver(sender, receiver);
transceiver->internal()->set_direction(
RtpTransceiverDirection::kRecvOnly); if (type == SdpType::kOffer) {
transceivers()->StableState(transceiver)->set_newly_created();
}
}
RTC_DCHECK(transceiver);
// 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,
pc_->GetCryptoOptions()
.srtp.enable_encrypted_rtp_header_extensions)) {
RTCError error =
DisableSimulcastInSender(transceiver->internal()->sender_internal()); if (!error.ok()) {
RTC_LOG(LS_ERROR) << "Failed to remove rejected simulcast."; return std::move(error);
}
}
}
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) {
transceivers()
->StableState(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);
}
void SdpOfferAnswerHandler::FillInMissingRemoteMids(
cricket::SessionDescription* new_remote_description) {
RTC_DCHECK_RUN_ON(signaling_thread());
RTC_DCHECK(new_remote_description); const cricket::ContentInfos no_infos; const cricket::ContentInfos& local_contents =
(local_description() ? local_description()->description()->contents()
: no_infos); const cricket::ContentInfos& remote_contents =
(remote_description() ? remote_description()->description()->contents()
: no_infos); for (size_t i = 0; i < new_remote_description->contents().size(); ++i) {
cricket::ContentInfo& content = new_remote_description->contents()[i]; if (!content.name.empty()) { continue;
}
std::string new_mid;
absl::string_view source_explanation; if (IsUnifiedPlan()) { if (i < local_contents.size()) {
new_mid = local_contents[i].name;
source_explanation = "from the matching local media section";
} elseif (i < remote_contents.size()) {
new_mid = remote_contents[i].name;
source_explanation = "from the matching previous remote media section";
} else {
new_mid = mid_generator_.GenerateString();
source_explanation = "generated just now";
}
} else {
new_mid = std::string(
GetDefaultMidForPlanB(content.media_description()->type()));
source_explanation = "to match pre-existing behavior";
}
RTC_DCHECK(!new_mid.empty());
content.name = new_mid;
new_remote_description->transport_infos()[i].content_name = new_mid;
RTC_LOG(LS_INFO) << "SetRemoteDescription: Remote media section at i=" << i
<< " is missing an a=mid line. Filling in the value '"
<< new_mid << "' " << source_explanation << ".";
}
}
rtc::scoped_refptr<RtpTransceiverProxyWithInternal<RtpTransceiver>>
SdpOfferAnswerHandler::FindAvailableTransceiverToReceive(
cricket::MediaType media_type) const {
RTC_DCHECK_RUN_ON(signaling_thread());
RTC_DCHECK(IsUnifiedPlan()); // From JSEP section 5.10 (Applying a Remote Description): // If the m= section is sendrecv or recvonly, and there are RtpTransceivers of // the same type that were added to the PeerConnection by addTrack and are not // associated with any m= section and are not stopped, find the first such // RtpTransceiver. for (auto transceiver : transceivers()->List()) { if (transceiver->media_type() == media_type &&
transceiver->internal()->created_by_addtrack() && !transceiver->mid() &&
!transceiver->stopped()) { return transceiver;
}
} return nullptr;
}
const cricket::ContentInfo*
SdpOfferAnswerHandler::FindMediaSectionForTransceiver( const RtpTransceiver* transceiver, const SessionDescriptionInterface* sdesc) const {
RTC_DCHECK_RUN_ON(signaling_thread());
RTC_DCHECK(transceiver);
RTC_DCHECK(sdesc); if (IsUnifiedPlan()) { if (!transceiver->mid()) { // This transceiver is not associated with a media section yet. return nullptr;
} return sdesc->description()->GetContentByName(*transceiver->mid());
} else { // Plan B only allows at most one audio and one video section, so use the // first media section of that type. return cricket::GetFirstMediaContent(sdesc->description()->contents(),
transceiver->media_type());
}
}
// Allow fallback for using obsolete SCTP syntax. // Note that the default in `session_options` is true, while // the default in `options` is false.
session_options->use_obsolete_sctp_sdp =
offer_answer_options.use_obsolete_sctp_sdp;
}
// By default, generate sendrecv/recvonly m= sections.
recv_audio = true;
recv_video = true;
} // By default, only offer a new m= section if we have media to send with it. bool offer_new_audio_description = send_audio; bool offer_new_video_description = send_video; if (ConfiguredForMedia()) { // The "offer_to_receive_X" options allow those defaults to be overridden. if (offer_answer_options.offer_to_receive_audio !=
PeerConnectionInterface::RTCOfferAnswerOptions::kUndefined) {
recv_audio = (offer_answer_options.offer_to_receive_audio > 0);
offer_new_audio_description =
offer_new_audio_description ||
(offer_answer_options.offer_to_receive_audio > 0);
} if (offer_answer_options.offer_to_receive_video !=
RTCOfferAnswerOptions::kUndefined) {
recv_video = (offer_answer_options.offer_to_receive_video > 0);
offer_new_video_description =
offer_new_video_description ||
(offer_answer_options.offer_to_receive_video > 0);
}
}
std::optional<size_t> audio_index;
std::optional<size_t> video_index;
std::optional<size_t> data_index; // If a current description exists, generate m= sections in the same order, // using the first audio/video/data section that appears and rejecting // extraneous ones. if (local_description()) {
GenerateMediaDescriptionOptions(
local_description(),
RtpTransceiverDirectionFromSendRecv(send_audio, recv_audio),
RtpTransceiverDirectionFromSendRecv(send_video, recv_video),
&audio_index, &video_index, &data_index, session_options);
}
void SdpOfferAnswerHandler::GetOptionsForUnifiedPlanOffer( const RTCOfferAnswerOptions& offer_answer_options,
cricket::MediaSessionOptions* session_options) { // Rules for generating an offer are dictated by JSEP sections 5.2.1 (Initial // Offers) and 5.2.2 (Subsequent Offers).
RTC_DCHECK_EQ(session_options->media_description_options.size(), 0); const ContentInfos no_infos; const ContentInfos& local_contents =
(local_description() ? local_description()->description()->contents()
: no_infos); const ContentInfos& remote_contents =
(remote_description() ? remote_description()->description()->contents()
: no_infos); // The mline indices that can be recycled. New transceivers should reuse these // slots first.
std::queue<size_t> recycleable_mline_indices; // First, go through each media section that exists in either the local or // remote description and generate a media section in this offer for the // associated transceiver. If a media section can be recycled, generate a // default, rejected media section here that can be later overwritten. for (size_t i = 0;
i < std::max(local_contents.size(), remote_contents.size()); ++i) { // Either `local_content` or `remote_content` is non-null. const ContentInfo* local_content =
(i < local_contents.size() ? &local_contents[i] : nullptr); const ContentInfo* current_local_content =
GetContentByIndex(current_local_description(), i); const ContentInfo* remote_content =
(i < remote_contents.size() ? &remote_contents[i] : nullptr); const ContentInfo* current_remote_content =
GetContentByIndex(current_remote_description(), i); bool had_been_rejected =
(current_local_content && current_local_content->rejected) ||
(current_remote_content && current_remote_content->rejected); const std::string& mid =
(local_content ? local_content->name : remote_content->name);
cricket::MediaType media_type =
(local_content ? local_content->media_description()->type()
: remote_content->media_description()->type()); if (media_type == cricket::MEDIA_TYPE_AUDIO ||
media_type == cricket::MEDIA_TYPE_VIDEO) { // A media section is considered eligible for recycling if it is marked as // rejected in either the current local or current remote description. auto transceiver = transceivers()->FindByMid(mid); if (!transceiver) { // No associated transceiver. The media section has been stopped.
recycleable_mline_indices.push(i);
session_options->media_description_options.push_back(
cricket::MediaDescriptionOptions(media_type, mid,
RtpTransceiverDirection::kInactive, /*stopped=*/true));
} else { // NOTE: a stopping transceiver should be treated as a stopped one in // createOffer as specified in // https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-createoffer. if (had_been_rejected && transceiver->stopping()) {
session_options->media_description_options.push_back(
cricket::MediaDescriptionOptions(
transceiver->media_type(), mid,
RtpTransceiverDirection::kInactive, /*stopped=*/true));
recycleable_mline_indices.push(i);
} else {
session_options->media_description_options.push_back(
GetMediaDescriptionOptionsForTransceiver(
transceiver->internal(), mid, /*is_create_offer=*/true)); // CreateOffer shouldn't really cause any state changes in // PeerConnection, but we need a way to match new transceivers to new // media sections in SetLocalDescription and JSEP specifies this is // done by recording the index of the media section generated for the // transceiver in the offer.
transceiver->internal()->set_mline_index(i);
}
}
} elseif (media_type == cricket::MEDIA_TYPE_UNSUPPORTED) {
RTC_DCHECK(local_content->rejected);
session_options->media_description_options.push_back(
cricket::MediaDescriptionOptions(media_type, mid,
RtpTransceiverDirection::kInactive, /*stopped=*/true));
} else {
RTC_CHECK_EQ(cricket::MEDIA_TYPE_DATA, media_type); if (had_been_rejected) {
session_options->media_description_options.push_back(
GetMediaDescriptionOptionsForRejectedData(mid));
} else { constauto data_mid = pc_->sctp_mid(); if (data_mid.has_value() && mid == data_mid.value()) {
session_options->media_description_options.push_back(
GetMediaDescriptionOptionsForActiveData(mid));
} else { if (!data_mid.has_value()) {
RTC_LOG(LS_ERROR) << "Datachannel transport not available: " << mid;
}
session_options->media_description_options.push_back(
GetMediaDescriptionOptionsForRejectedData(mid));
}
}
}
}
// Next, look for transceivers that are newly added (that is, are not stopped // and not associated). Reuse media sections marked as recyclable first, // otherwise append to the end of the offer. New media sections should be // added in the order they were added to the PeerConnection. if (ConfiguredForMedia()) { for (constauto& transceiver : transceivers()->ListInternal()) { if (transceiver->mid() || transceiver->stopping()) { continue;
}
size_t mline_index; if (!recycleable_mline_indices.empty()) {
mline_index = recycleable_mline_indices.front();
recycleable_mline_indices.pop();
session_options->media_description_options[mline_index] =
GetMediaDescriptionOptionsForTransceiver(
transceiver, mid_generator_.GenerateString(), /*is_create_offer=*/true);
} else {
mline_index = session_options->media_description_options.size();
session_options->media_description_options.push_back(
GetMediaDescriptionOptionsForTransceiver(
transceiver, mid_generator_.GenerateString(), /*is_create_offer=*/true));
} // See comment above for why CreateOffer changes the transceiver's state.
transceiver->set_mline_index(mline_index);
}
} // Lastly, add a m-section if we have requested local data channels and an // m section does not already exist. if (!pc_->sctp_mid() && data_channel_controller()->HasDataChannels()) { // Attempt to recycle a stopped m-line. // TODO(crbug.com/1442604): sctp_mid() should return the mid if one was // ever created but rejected. bool recycled = false; for (size_t i = 0; i < session_options->media_description_options.size();
i++) { auto media_description = session_options->media_description_options[i]; if (media_description.type == cricket::MEDIA_TYPE_DATA &&
media_description.stopped) {
session_options->media_description_options[i] =
GetMediaDescriptionOptionsForActiveData(media_description.mid);
recycled = true; break;
}
} if (!recycled) {
session_options->media_description_options.push_back(
GetMediaDescriptionOptionsForActiveData(
mid_generator_.GenerateString()));
}
}
}
if (ConfiguredForMedia()) { // Figure out transceiver directional preferences.
send_audio =
!rtp_manager()->GetAudioTransceiver()->internal()->senders().empty();
send_video =
!rtp_manager()->GetVideoTransceiver()->internal()->senders().empty();
// By default, generate sendrecv/recvonly m= sections. The direction is also // restricted by the direction in the offer.
recv_audio = true;
recv_video = true;
// The "offer_to_receive_X" options allow those defaults to be overridden. if (offer_answer_options.offer_to_receive_audio !=
RTCOfferAnswerOptions::kUndefined) {
recv_audio = (offer_answer_options.offer_to_receive_audio > 0);
} if (offer_answer_options.offer_to_receive_video !=
RTCOfferAnswerOptions::kUndefined) {
recv_video = (offer_answer_options.offer_to_receive_video > 0);
}
}
// Generate m= sections that match those in the offer. // Note that mediasession.cc will handle intersection our preferred // direction with the offered direction.
GenerateMediaDescriptionOptions(
remote_description(),
RtpTransceiverDirectionFromSendRecv(send_audio, recv_audio),
RtpTransceiverDirectionFromSendRecv(send_video, recv_video), &audio_index,
&video_index, &data_index, session_options);
if (ConfiguredForMedia()) {
AddPlanBRtpSenderOptions(rtp_manager()->GetSendersInternal(),
audio_media_description_options,
video_media_description_options,
offer_answer_options.num_simulcast_layers);
}
}
void SdpOfferAnswerHandler::GetOptionsForUnifiedPlanAnswer( const PeerConnectionInterface::RTCOfferAnswerOptions& offer_answer_options,
cricket::MediaSessionOptions* session_options) { // Rules for generating an answer are dictated by JSEP sections 5.3.1 (Initial // Answers) and 5.3.2 (Subsequent Answers).
RTC_DCHECK(remote_description());
RTC_DCHECK(remote_description()->GetType() == SdpType::kOffer); for (const ContentInfo& content :
remote_description()->description()->contents()) {
cricket::MediaType media_type = content.media_description()->type(); if (media_type == cricket::MEDIA_TYPE_AUDIO ||
media_type == cricket::MEDIA_TYPE_VIDEO) { auto transceiver = transceivers()->FindByMid(content.name); if (transceiver) {
session_options->media_description_options.push_back(
GetMediaDescriptionOptionsForTransceiver(
transceiver->internal(), content.name, /*is_create_offer=*/false));
} else { // This should only happen with rejected transceivers.
RTC_DCHECK(content.rejected);
session_options->media_description_options.push_back(
cricket::MediaDescriptionOptions(media_type, content.name,
RtpTransceiverDirection::kInactive, /*stopped=*/true));
}
} elseif (media_type == cricket::MEDIA_TYPE_UNSUPPORTED) {
RTC_DCHECK(content.rejected);
session_options->media_description_options.push_back(
cricket::MediaDescriptionOptions(media_type, content.name,
RtpTransceiverDirection::kInactive, /*stopped=*/true));
} else {
RTC_CHECK_EQ(cricket::MEDIA_TYPE_DATA, media_type); // Reject all data sections if data channels are disabled. // Reject a data section if it has already been rejected. // Reject all data sections except for the first one. if (content.rejected || content.name != *(pc_->sctp_mid())) {
session_options->media_description_options.push_back(
GetMediaDescriptionOptionsForRejectedData(content.name));
} else {
session_options->media_description_options.push_back(
GetMediaDescriptionOptionsForActiveData(content.name));
}
}
}
}
constchar* SdpOfferAnswerHandler::SessionErrorToString(
SessionError error) const { switch (error) { case SessionError::kNone: return"ERROR_NONE"; case SessionError::kContent: return"ERROR_CONTENT"; case SessionError::kTransport: return"ERROR_TRANSPORT";
}
RTC_DCHECK_NOTREACHED(); return"";
}
void SdpOfferAnswerHandler::ProcessRemovalOfRemoteTrack(
rtc::scoped_refptr<RtpTransceiverProxyWithInternal<RtpTransceiver>>
transceiver,
std::vector<rtc::scoped_refptr<RtpTransceiverInterface>>* remove_list,
std::vector<rtc::scoped_refptr<MediaStreamInterface>>* removed_streams) {
RTC_DCHECK(transceiver->mid());
RTC_LOG(LS_INFO) << "Processing the removal of a track for MID="
<< *transceiver->mid();
std::vector<rtc::scoped_refptr<MediaStreamInterface>> previous_streams =
transceiver->internal()->receiver_internal()->streams(); // This will remove the remote track from the streams.
transceiver->internal()->receiver_internal()->set_stream_ids({});
remove_list->push_back(transceiver);
RemoveRemoteStreamsIfEmpty(previous_streams, removed_streams);
}
void SdpOfferAnswerHandler::RemoveRemoteStreamsIfEmpty( const std::vector<rtc::scoped_refptr<MediaStreamInterface>>& remote_streams,
std::vector<rtc::scoped_refptr<MediaStreamInterface>>* removed_streams) {
RTC_DCHECK_RUN_ON(signaling_thread()); // TODO(https://crbug.com/webrtc/9480): When we use stream IDs instead of // streams, see if the stream was removed by checking if this was the last // receiver with that stream ID. for (constauto& remote_stream : remote_streams) { if (remote_stream->GetAudioTracks().empty() &&
remote_stream->GetVideoTracks().empty()) {
remote_streams_->RemoveStream(remote_stream.get());
removed_streams->push_back(remote_stream);
}
}
}
// Find removed tracks. I.e., tracks where the track id, stream id or ssrc // don't match the new StreamParam. for (auto sender_it = current_senders->begin();
sender_it != current_senders->end(); /* incremented manually */) { const RtpSenderInfo& info = *sender_it; const cricket::StreamParams* params =
cricket::GetStreamBySsrc(streams, info.first_ssrc); if (!params || params->id != info.sender_id ||
params->first_stream_id() != info.stream_id) {
rtp_manager()->OnLocalSenderRemoved(info, media_type);
sender_it = current_senders->erase(sender_it);
} else {
++sender_it;
}
}
// Find new and active senders. for (const cricket::StreamParams& params : streams) { // The sync_label is the MediaStream label and the `stream.id` is the // sender id. const std::string& stream_id = params.first_stream_id(); const std::string& sender_id = params.id;
uint32_t ssrc = params.first_ssrc(); const RtpSenderInfo* sender_info =
rtp_manager()->FindSenderInfo(*current_senders, stream_id, sender_id); if (!sender_info) {
current_senders->push_back(RtpSenderInfo(stream_id, sender_id, ssrc));
rtp_manager()->OnLocalSenderAdded(current_senders->back(), media_type);
}
}
}
// Find removed senders. I.e., senders where the sender id or ssrc don't match // the new StreamParam. for (auto sender_it = current_senders->begin();
sender_it != current_senders->end(); /* incremented manually */) { const RtpSenderInfo& info = *sender_it; const cricket::StreamParams* params =
cricket::GetStreamBySsrc(streams, info.first_ssrc);
std::string params_stream_id; if (params) {
params_stream_id =
(!params->first_stream_id().empty() ? params->first_stream_id()
: kDefaultStreamId);
} bool sender_exists = params && params->id == info.sender_id &&
params_stream_id == info.stream_id; // If this is a default track, and we still need it, don't remove it. if ((info.stream_id == kDefaultStreamId && default_sender_needed) ||
sender_exists) {
++sender_it;
} else {
rtp_manager()->OnRemoteSenderRemoved(
info, remote_streams_->find(info.stream_id), media_type);
sender_it = current_senders->erase(sender_it);
}
}
// Find new and active senders. for (const cricket::StreamParams& params : streams) { if (!params.has_ssrcs()) { // The remote endpoint has streams, but didn't signal ssrcs. For an active // sender, this means it is coming from a Unified Plan endpoint,so we just // create a default.
default_sender_needed = true; break;
}
// `params.id` is the sender id and the stream id uses the first of // `params.stream_ids`. The remote description could come from a Unified // Plan endpoint, with multiple or no stream_ids() signaled. Since this is // not supported in Plan B, we just take the first here and create the // default stream ID if none is specified. const std::string& stream_id =
(!params.first_stream_id().empty() ? params.first_stream_id()
: kDefaultStreamId); const std::string& sender_id = params.id;
uint32_t ssrc = params.first_ssrc();
rtc::scoped_refptr<MediaStreamInterface> stream(
remote_streams_->find(stream_id)); if (!stream) { // This is a new MediaStream. Create a new remote MediaStream.
stream = MediaStreamProxy::Create(rtc::Thread::Current(),
MediaStream::Create(stream_id));
remote_streams_->AddStream(stream);
new_streams->AddStream(stream);
}
if (ConfiguredForMedia()) { // Note: This will perform a BlockingCall over to the worker thread, which // we'll also do in a loop below. if (!UpdatePayloadTypeDemuxingState(source, bundle_groups_by_mid)) { // Note that this is never expected to fail, since RtpDemuxer doesn't // return an error when changing payload type demux criteria, which is all // this does.
LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR, "Failed to update payload type demuxing state.");
}
// Push down the new SDP media section for each audio/video transceiver. auto rtp_transceivers = transceivers()->ListInternal();
std::vector<
std::pair<cricket::ChannelInterface*, const MediaContentDescription*>>
channels; for (constauto& transceiver : rtp_transceivers) { const ContentInfo* content_info =
FindMediaSectionForTransceiver(transceiver, sdesc);
cricket::ChannelInterface* channel = transceiver->channel(); if (!channel || !content_info || content_info->rejected) { continue;
} const MediaContentDescription* content_desc =
content_info->media_description(); if (!content_desc) { continue;
}
// This for-loop of invokes helps audio impairment during re-negotiations. // One of the causes is that downstairs decoder creation is synchronous at // the moment, and that a decoder is created for each codec listed in the // SDP. // // TODO(bugs.webrtc.org/12840): consider merging the invokes again after // these projects have shipped: // - bugs.webrtc.org/12462 // - crbug.com/1157227 // - crbug.com/1187289 for (constauto& entry : channels) {
std::string error; bool success = context_->worker_thread()->BlockingCall([&]() { return (source == cricket::CS_LOCAL)
? entry.first->SetLocalContent(entry.second, type, error)
: entry.first->SetRemoteContent(entry.second, type, error);
}); if (!success) {
LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, error);
}
}
} // Need complete offer/answer with an SCTP m= section before starting SCTP, // according to https://tools.ietf.org/html/draft-ietf-mmusic-sctp-sdp-19 if (pc_->sctp_mid() && local_description() && remote_description()) { auto local_sctp_description = cricket::GetFirstSctpDataContentDescription(
local_description()->description()); auto remote_sctp_description = cricket::GetFirstSctpDataContentDescription(
remote_description()->description()); if (local_sctp_description && remote_sctp_description) { int max_message_size; // A remote max message size of zero means "any size supported". // We configure the connection with our own max message size. if (remote_sctp_description->max_message_size() == 0) {
max_message_size = local_sctp_description->max_message_size();
} else {
max_message_size =
std::min(local_sctp_description->max_message_size(),
remote_sctp_description->max_message_size());
}
pc_->StartSctpTransport(local_sctp_description->port(),
remote_sctp_description->port(),
max_message_size);
}
}
void SdpOfferAnswerHandler::RemoveStoppedTransceivers() {
TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::RemoveStoppedTransceivers");
RTC_DCHECK_RUN_ON(signaling_thread()); // 3.2.10.1: For each transceiver in the connection's set of transceivers // run the following steps: if (!IsUnifiedPlan()) return; if (!ConfiguredForMedia()) { return;
} // Traverse a copy of the transceiver list. auto transceiver_list = transceivers()->List(); for (auto transceiver : transceiver_list) { // 3.2.10.1.1: If transceiver is stopped, associated with an m= section // and the associated m= section is rejected in // connection.[[CurrentLocalDescription]] or // connection.[[CurrentRemoteDescription]], remove the // transceiver from the connection's set of transceivers. if (!transceiver->stopped()) { continue;
} const ContentInfo* local_content = FindMediaSectionForTransceiver(
transceiver->internal(), local_description()); const ContentInfo* remote_content = FindMediaSectionForTransceiver(
transceiver->internal(), remote_description()); if ((local_content && local_content->rejected) ||
(remote_content && remote_content->rejected)) {
RTC_LOG(LS_INFO) << "Dissociating transceiver" " since the media section is being recycled.";
transceiver->internal()->set_mid(std::nullopt);
transceiver->internal()->set_mline_index(std::nullopt);
} elseif (!local_content && !remote_content) { // TODO(bugs.webrtc.org/11973): Consider if this should be removed already // See https://github.com/w3c/webrtc-pc/issues/2576
RTC_LOG(LS_INFO)
<< "Dropping stopped transceiver that was never associated";
}
transceivers()->Remove(transceiver);
}
}
void SdpOfferAnswerHandler::RemoveUnusedChannels( const SessionDescription* desc) {
RTC_DCHECK_RUN_ON(signaling_thread()); if (ConfiguredForMedia()) { // Destroy video channel first since it may have a pointer to the // voice channel. const cricket::ContentInfo* video_info =
cricket::GetFirstVideoContent(desc); if (!video_info || video_info->rejected) {
rtp_manager()->GetVideoTransceiver()->internal()->ClearChannel();
}
const cricket::ContentInfo* audio_info =
cricket::GetFirstAudioContent(desc); if (!audio_info || audio_info->rejected) {
rtp_manager()->GetAudioTransceiver()->internal()->ClearChannel();
}
} const cricket::ContentInfo* data_info = cricket::GetFirstDataContent(desc); if (!data_info) {
RTCError error(RTCErrorType::OPERATION_ERROR_WITH_DATA, "No data channel section in the description.");
error.set_error_detail(RTCErrorDetailType::DATA_CHANNEL_FAILURE);
pc_->DestroyDataChannelTransport(error);
} elseif (data_info->rejected) {
rtc::StringBuilder sb;
sb << "Rejected data channel with mid=" << data_info->name << ".";
// We need to check the local/remote description for the Transport instead of // the session, because a new Transport added during renegotiation may have // them unset while the session has them set from the previous negotiation. // Not doing so may trigger the auto generation of transport description and // mess up DTLS identity information, ICE credential, etc. bool SdpOfferAnswerHandler::ReadyToUseRemoteCandidate( const IceCandidateInterface* candidate, const SessionDescriptionInterface* remote_desc, bool* valid) {
RTC_DCHECK_RUN_ON(signaling_thread());
*valid = true;
const cricket::ContentInfo* data = cricket::GetFirstDataContent(&desc); if (data && !data->rejected && !pc_->CreateDataChannelTransport(data->name)) {
LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR, "Failed to create data channel.");
}
return RTCError::OK();
}
void SdpOfferAnswerHandler::DestroyMediaChannels() {
RTC_DCHECK_RUN_ON(signaling_thread()); if (!transceivers()) { return;
}
RTC_LOG_THREAD_BLOCK_COUNT();
// Destroy video channels first since they may have a pointer to a voice // channel. auto list = transceivers()->List();
RTC_DCHECK_BLOCK_COUNT_NO_MORE_THAN(0);
for (constauto& transceiver : list) { if (transceiver->media_type() == cricket::MEDIA_TYPE_VIDEO) {
transceiver->internal()->ClearChannel();
}
} for (constauto& transceiver : list) { if (transceiver->media_type() == cricket::MEDIA_TYPE_AUDIO) {
transceiver->internal()->ClearChannel();
}
}
}
void SdpOfferAnswerHandler::GenerateMediaDescriptionOptions( const SessionDescriptionInterface* session_desc,
RtpTransceiverDirection audio_direction,
RtpTransceiverDirection video_direction,
std::optional<size_t>* audio_index,
std::optional<size_t>* video_index,
std::optional<size_t>* data_index,
cricket::MediaSessionOptions* session_options) {
RTC_DCHECK_RUN_ON(signaling_thread()); for (const cricket::ContentInfo& content :
session_desc->description()->contents()) { if (IsAudioContent(&content)) { // If we already have an audio m= section, reject this extra one. if (*audio_index) {
session_options->media_description_options.push_back(
cricket::MediaDescriptionOptions(
cricket::MEDIA_TYPE_AUDIO, content.name,
RtpTransceiverDirection::kInactive, /*stopped=*/true));
} else { bool stopped = (audio_direction == RtpTransceiverDirection::kInactive);
session_options->media_description_options.push_back(
cricket::MediaDescriptionOptions(cricket::MEDIA_TYPE_AUDIO,
content.name, audio_direction,
stopped));
*audio_index = session_options->media_description_options.size() - 1;
}
session_options->media_description_options.back().header_extensions =
media_engine()->voice().GetRtpHeaderExtensions();
} elseif (IsVideoContent(&content)) { // If we already have an video m= section, reject this extra one. if (*video_index) {
session_options->media_description_options.push_back(
cricket::MediaDescriptionOptions(
cricket::MEDIA_TYPE_VIDEO, content.name,
RtpTransceiverDirection::kInactive, /*stopped=*/true));
} else { bool stopped = (video_direction == RtpTransceiverDirection::kInactive);
session_options->media_description_options.push_back(
cricket::MediaDescriptionOptions(cricket::MEDIA_TYPE_VIDEO,
content.name, video_direction,
stopped));
*video_index = session_options->media_description_options.size() - 1;
}
session_options->media_description_options.back().header_extensions =
media_engine()->video().GetRtpHeaderExtensions();
} elseif (IsUnsupportedContent(&content)) {
session_options->media_description_options.push_back(
cricket::MediaDescriptionOptions(cricket::MEDIA_TYPE_UNSUPPORTED,
content.name,
RtpTransceiverDirection::kInactive, /*stopped=*/true));
} else {
RTC_DCHECK(IsDataContent(&content)); // If we already have an data m= section, reject this extra one. if (*data_index) {
session_options->media_description_options.push_back(
GetMediaDescriptionOptionsForRejectedData(content.name));
} else {
session_options->media_description_options.push_back(
GetMediaDescriptionOptionsForActiveData(content.name));
*data_index = session_options->media_description_options.size() - 1;
}
}
}
}
cricket::MediaDescriptionOptions
SdpOfferAnswerHandler::GetMediaDescriptionOptionsForActiveData( const std::string& mid) const {
RTC_DCHECK_RUN_ON(signaling_thread()); // Direction for data sections is meaningless, but legacy endpoints might // expect sendrecv.
cricket::MediaDescriptionOptions options(cricket::MEDIA_TYPE_DATA, mid,
RtpTransceiverDirection::kSendRecv, /*stopped=*/false); return options;
}
bool SdpOfferAnswerHandler::UpdatePayloadTypeDemuxingState(
cricket::ContentSource source, const std::map<std::string, const cricket::ContentGroup*>&
bundle_groups_by_mid) {
TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::UpdatePayloadTypeDemuxingState");
RTC_DCHECK_RUN_ON(signaling_thread()); // We may need to delete any created default streams and disable creation of // new ones on the basis of payload type. This is needed to avoid SSRC // collisions in Call's RtpDemuxer, in the case that a transceiver has // created a default stream, and then some other channel gets the SSRC // signaled in the corresponding Unified Plan "m=" section. Specifically, we // need to disable payload type based demuxing when two bundled "m=" sections // are using the same payload type(s). For more context // see https://bugs.chromium.org/p/webrtc/issues/detail?id=11477 const SessionDescriptionInterface* sdesc =
(source == cricket::CS_LOCAL ? local_description()
: remote_description()); struct PayloadTypes {
std::set<int> audio_payload_types;
std::set<int> video_payload_types; bool pt_demuxing_possible_audio = true; bool pt_demuxing_possible_video = true;
};
std::map<const cricket::ContentGroup*, PayloadTypes> payload_types_by_bundle; // If the MID is missing from *any* receiving m= section, this is set to true. bool mid_header_extension_missing_audio = false; bool mid_header_extension_missing_video = false; for (auto& content_info : sdesc->description()->contents()) { auto it = bundle_groups_by_mid.find(content_info.name); const cricket::ContentGroup* bundle_group =
it != bundle_groups_by_mid.end() ? it->second : nullptr; // If this m= section isn't bundled, it's safe to demux by payload type // since other m= sections using the same payload type will also be using // different transports. if (!bundle_group) { continue;
}
PayloadTypes* payload_types = &payload_types_by_bundle[bundle_group]; if (content_info.rejected ||
(source == cricket::ContentSource::CS_LOCAL &&
!RtpTransceiverDirectionHasRecv(
content_info.media_description()->direction())) ||
(source == cricket::ContentSource::CS_REMOTE &&
!RtpTransceiverDirectionHasSend(
content_info.media_description()->direction()))) { // Ignore transceivers that are not receiving. continue;
} const cricket::MediaType media_type =
content_info.media_description()->type(); if (media_type == cricket::MediaType::MEDIA_TYPE_AUDIO ||
media_type == cricket::MediaType::MEDIA_TYPE_VIDEO) { if (media_type == cricket::MediaType::MEDIA_TYPE_AUDIO &&
!mid_header_extension_missing_audio) {
mid_header_extension_missing_audio =
!ContentHasHeaderExtension(content_info, RtpExtension::kMidUri);
} elseif (media_type == cricket::MEDIA_TYPE_VIDEO &&
!mid_header_extension_missing_video) {
mid_header_extension_missing_video =
!ContentHasHeaderExtension(content_info, RtpExtension::kMidUri);
} const cricket::MediaContentDescription* media_desc =
content_info.media_description(); for (const cricket::Codec& codec : media_desc->codecs()) { if (media_type == cricket::MediaType::MEDIA_TYPE_AUDIO) { if (payload_types->audio_payload_types.count(codec.id)) { // Two m= sections are using the same payload type, thus demuxing // by payload type is not possible. if (media_type == cricket::MediaType::MEDIA_TYPE_AUDIO) {
payload_types->pt_demuxing_possible_audio = false;
}
}
payload_types->audio_payload_types.insert(codec.id);
} elseif (media_type == cricket::MEDIA_TYPE_VIDEO) { if (payload_types->video_payload_types.count(codec.id)) { // Two m= sections are using the same payload type, thus demuxing // by payload type is not possible.
payload_types->pt_demuxing_possible_video = false;
}
payload_types->video_payload_types.insert(codec.id);
}
}
}
}
// In Unified Plan, payload type demuxing is useful for legacy endpoints that // don't support the MID header extension, but it can also cause incorrrect // forwarding of packets when going from one m= section to multiple m= // sections in the same BUNDLE. This only happens if media arrives prior to // negotiation, but this can cause missing video and unsignalled ssrc bugs // severe enough to warrant disabling PT demuxing in such cases. Therefore, if // a MID header extension is present on all m= sections for a given kind // (audio/video) then we use that as an OK to disable payload type demuxing in // BUNDLEs of that kind. However if PT demuxing was ever turned on (e.g. MID // was ever removed on ANY m= section of that kind) then we continue to allow // PT demuxing in order to prevent disabling it in follow-up O/A exchanges and // allowing early media by PT. bool bundled_pt_demux_allowed_audio = !IsUnifiedPlan() ||
mid_header_extension_missing_audio ||
pt_demuxing_has_been_used_audio_; bool bundled_pt_demux_allowed_video = !IsUnifiedPlan() ||
mid_header_extension_missing_video ||
pt_demuxing_has_been_used_video_;
// Gather all updates ahead of time so that all channels can be updated in a // single BlockingCall; necessary due to thread guards.
std::vector<std::pair<bool, cricket::ChannelInterface*>> channels_to_update; for (constauto& transceiver : transceivers()->ListInternal()) {
cricket::ChannelInterface* channel = transceiver->channel(); const ContentInfo* content =
FindMediaSectionForTransceiver(transceiver, sdesc); if (!channel || !content) { continue;
}
// TODO(bugs.webrtc.org/11993): This BlockingCall() will also block on the // network thread for every demuxer sink that needs to be updated. The demuxer // state needs to be fully (and only) managed on the network thread and once // that's the case, there's no need to stop by on the worker. Ideally we could // also do this without blocking. return context_->worker_thread()->BlockingCall([&channels_to_update]() { for (constauto& it : channels_to_update) { if (!it.second->SetPayloadTypeDemuxingEnabled(it.first)) { // Note that the state has already been irrevocably changed at this // point. Is it useful to stop the loop? returnfalse;
}
} returntrue;
});
}
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