/* * Copyright 2020 The WebRTC project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */ #include "pc/sdp_offer_answer.h" #include #include #include #include #include #include #include #include #include "absl/algorithm/container.h" #include "absl/memory/memory.h" #include "absl/strings/match.h" #include "absl/strings/string_view.h" #include "api/array_view.h" #include "api/crypto/crypto_options.h" #include "api/dtls_transport_interface.h" #include "api/field_trials_view.h" #include "api/rtp_parameters.h" #include "api/rtp_receiver_interface.h" #include "api/rtp_sender_interface.h" #include "api/video/builtin_video_bitrate_allocator_factory.h" #include "media/base/codec.h" #include "media/base/rid_description.h" #include "p2p/base/ice_transport_internal.h" #include "p2p/base/p2p_constants.h" #include "p2p/base/p2p_transport_channel.h" #include "p2p/base/port.h" #include "p2p/base/transport_description.h" #include "p2p/base/transport_description_factory.h" #include "p2p/base/transport_info.h" #include "pc/channel_interface.h" #include "pc/dtls_transport.h" #include "pc/legacy_stats_collector.h" #include "pc/media_stream.h" #include "pc/media_stream_proxy.h" #include "pc/peer_connection_internal.h" #include "pc/peer_connection_message_handler.h" #include "pc/rtp_media_utils.h" #include "pc/rtp_receiver_proxy.h" #include "pc/rtp_sender.h" #include "pc/rtp_sender_proxy.h" #include "pc/simulcast_description.h" #include "pc/usage_pattern.h" #include "pc/used_ids.h" #include "pc/webrtc_session_description_factory.h" #include "rtc_base/helpers.h" #include "rtc_base/logging.h" #include "rtc_base/rtc_certificate.h" #include "rtc_base/ssl_stream_adapter.h" #include "rtc_base/string_encode.h" #include "rtc_base/strings/string_builder.h" #include "rtc_base/trace_event.h" #include "system_wrappers/include/metrics.h" using cricket::ContentInfo; using cricket::ContentInfos; using cricket::MediaContentDescription; using cricket::MediaProtocolType; using cricket::RidDescription; using cricket::RidDirection; using cricket::SessionDescription; using cricket::SimulcastDescription; using cricket::SimulcastLayer; using cricket::SimulcastLayerList; using cricket::StreamParams; using cricket::TransportInfo; namespace webrtc { namespace { typedef PeerConnectionInterface::RTCOfferAnswerOptions RTCOfferAnswerOptions; // Error messages const char kInvalidSdp[] = "Invalid session description."; const char kInvalidCandidates[] = "Description contains invalid candidates."; const char kBundleWithoutRtcpMux[] = "rtcp-mux must be enabled when BUNDLE " "is enabled."; const char kMlineMismatchInAnswer[] = "The order of m-lines in answer doesn't match order in offer. Rejecting " "answer."; const char kMlineMismatchInSubsequentOffer[] = "The order of m-lines in subsequent offer doesn't match order from " "previous offer/answer."; const char kSdpWithoutIceUfragPwd[] = "Called with SDP without ice-ufrag and ice-pwd."; const char kSdpWithoutDtlsFingerprint[] = "Called with SDP without DTLS fingerprint."; const char kSdpWithoutCrypto[] = "Called with SDP without crypto setup."; const char kSessionError[] = "Session error code: "; const char kSessionErrorDesc[] = "Session error description: "; // The length of RTCP CNAMEs. static const int kRtcpCnameLength = 16; // The maximum length of the MID attribute. static constexpr size_t kMidMaxSize = 16; const char kDefaultStreamId[] = "default"; // NOTE: Duplicated in peer_connection.cc: static const char kDefaultAudioSenderId[] = "defaulta0"; static const char kDefaultVideoSenderId[] = "defaultv0"; void NoteAddIceCandidateResult(int result) { RTC_HISTOGRAM_ENUMERATION("WebRTC.PeerConnection.AddIceCandidate", result, kAddIceCandidateMax); } std::map GetBundleGroupsByMid( const SessionDescription* desc) { std::vector bundle_groups = desc->GetGroupsByName(cricket::GROUP_TYPE_BUNDLE); std::map bundle_groups_by_mid; for (const cricket::ContentGroup* bundle_group : bundle_groups) { for (const std::string& content_name : bundle_group->content_names()) { bundle_groups_by_mid[content_name] = bundle_group; } } return bundle_groups_by_mid; } // Returns true if `new_desc` requests an ICE restart (i.e., new ufrag/pwd). bool CheckForRemoteIceRestart(const SessionDescriptionInterface* old_desc, const SessionDescriptionInterface* new_desc, const std::string& content_name) { if (!old_desc) { return false; } const SessionDescription* new_sd = new_desc->description(); const SessionDescription* old_sd = old_desc->description(); const ContentInfo* cinfo = new_sd->GetContentByName(content_name); if (!cinfo || cinfo->rejected) { return false; } // If the content isn't rejected, check if ufrag and password has changed. const cricket::TransportDescription* new_transport_desc = new_sd->GetTransportDescriptionByName(content_name); const cricket::TransportDescription* old_transport_desc = old_sd->GetTransportDescriptionByName(content_name); if (!new_transport_desc || !old_transport_desc) { // No transport description exists. This is not an ICE restart. return false; } if (cricket::IceCredentialsChanged( old_transport_desc->ice_ufrag, old_transport_desc->ice_pwd, new_transport_desc->ice_ufrag, new_transport_desc->ice_pwd)) { RTC_LOG(LS_INFO) << "Remote peer requests ICE restart for " << content_name << "."; return true; } return false; } // Generates a string error message for SetLocalDescription/SetRemoteDescription // from an RTCError. std::string GetSetDescriptionErrorMessage(cricket::ContentSource source, SdpType type, const RTCError& error) { rtc::StringBuilder oss; oss << "Failed to set " << (source == cricket::CS_LOCAL ? "local" : "remote") << " " << SdpTypeToString(type) << " sdp: "; RTC_DCHECK(!absl::StartsWith(error.message(), oss.str())) << error.message(); oss << error.message(); return oss.Release(); } std::string GetStreamIdsString(rtc::ArrayView stream_ids) { std::string output = "streams=["; const char* separator = ""; for (const auto& stream_id : stream_ids) { output.append(separator).append(stream_id); separator = ", "; } output.append("]"); return output; } const ContentInfo* FindTransceiverMSection( RtpTransceiver* transceiver, const SessionDescriptionInterface* session_description) { return transceiver->mid() ? session_description->description()->GetContentByName( *transceiver->mid()) : nullptr; } // If the direction is "recvonly" or "inactive", treat the description // as containing no streams. // See: https://code.google.com/p/webrtc/issues/detail?id=5054 std::vector GetActiveStreams( const cricket::MediaContentDescription* desc) { return RtpTransceiverDirectionHasSend(desc->direction()) ? desc->streams() : std::vector(); } // Logic to decide if an m= section can be recycled. This means that the new // m= section is not rejected, but the old local or remote m= section is // rejected. `old_content_one` and `old_content_two` refer to the m= section // of the old remote and old local descriptions in no particular order. // We need to check both the old local and remote because either // could be the most current from the latest negotation. bool IsMediaSectionBeingRecycled(SdpType type, const ContentInfo& content, const ContentInfo* old_content_one, const ContentInfo* old_content_two) { return type == SdpType::kOffer && !content.rejected && ((old_content_one && old_content_one->rejected) || (old_content_two && old_content_two->rejected)); } // Verify that the order of media sections in `new_desc` matches // `current_desc`. The number of m= sections in `new_desc` should be no // less than `current_desc`. In the case of checking an answer's // `new_desc`, the `current_desc` is the last offer that was set as the // local or remote. In the case of checking an offer's `new_desc` we // check against the local and remote descriptions stored from the last // negotiation, because either of these could be the most up to date for // possible rejected m sections. These are the `current_desc` and // `secondary_current_desc`. bool MediaSectionsInSameOrder(const SessionDescription& current_desc, const SessionDescription* secondary_current_desc, const SessionDescription& new_desc, const SdpType type) { if (current_desc.contents().size() > new_desc.contents().size()) { return false; } for (size_t i = 0; i < current_desc.contents().size(); ++i) { const cricket::ContentInfo* secondary_content_info = nullptr; if (secondary_current_desc && i < secondary_current_desc->contents().size()) { secondary_content_info = &secondary_current_desc->contents()[i]; } if (IsMediaSectionBeingRecycled(type, new_desc.contents()[i], ¤t_desc.contents()[i], secondary_content_info)) { // For new offer descriptions, if the media section can be recycled, it's // valid for the MID and media type to change. continue; } if (new_desc.contents()[i].name != current_desc.contents()[i].name) { return false; } const MediaContentDescription* new_desc_mdesc = new_desc.contents()[i].media_description(); const MediaContentDescription* current_desc_mdesc = current_desc.contents()[i].media_description(); if (new_desc_mdesc->type() != current_desc_mdesc->type()) { return false; } } return true; } bool MediaSectionsHaveSameCount(const SessionDescription& desc1, const SessionDescription& desc2) { return desc1.contents().size() == desc2.contents().size(); } // Checks that each non-rejected content has 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& 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& 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; return false; } if (tinfo->description.ice_ufrag.empty() || tinfo->description.ice_pwd.empty()) { RTC_LOG(LS_ERROR) << "Session description must have ice ufrag and pwd."; return false; } } return true; } RTCError ValidateMids(const cricket::SessionDescription& description) { std::set 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& 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 bundle_groups = description.GetGroupsByName(cricket::GROUP_TYPE_BUNDLE); for (const cricket::ContentGroup* bundle_group : bundle_groups) { std::map 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; } const auto type = media_description->type(); if (type == cricket::MEDIA_TYPE_AUDIO || type == cricket::MEDIA_TYPE_VIDEO) { for (const auto& 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& 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 bundle_groups = description.GetGroupsByName(cricket::GROUP_TYPE_BUNDLE); for (const cricket::ContentGroup* bundle_group : bundle_groups) { std::map 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 (const auto& 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; } const auto 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; } const auto media_description = content.media_description(); RTC_DCHECK(media_description); if (content.rejected || !media_description || !media_description->has_codecs()) { continue; } const auto type = media_description->type(); if (type == cricket::MEDIA_TYPE_AUDIO || type == cricket::MEDIA_TYPE_VIDEO) { for (const auto& 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(); } bool IsValidOfferToReceiveMedia(int value) { typedef PeerConnectionInterface::RTCOfferAnswerOptions Options; return (value >= Options::kUndefined) && (value <= Options::kMaxOfferToReceiveMedia); } bool ValidateOfferAnswerOptions( const PeerConnectionInterface::RTCOfferAnswerOptions& rtc_options) { return IsValidOfferToReceiveMedia(rtc_options.offer_to_receive_audio) && IsValidOfferToReceiveMedia(rtc_options.offer_to_receive_video); } // 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 GetSendEncodingsFromRemoteDescription( const MediaContentDescription& desc) { if (!desc.HasSimulcast()) { return {}; } std::vector result; const SimulcastDescription& simulcast = desc.simulcast_description(); // This is a remote description, the parameters we are after should appear // as receive streams. for (const auto& alternatives : simulcast.receive_layers()) { RTC_DCHECK(!alternatives.empty()); // There is currently no way to specify or choose from alternatives. // We will always use the first alternative, which is the most preferred. const SimulcastLayer& layer = alternatives[0]; RtpEncodingParameters parameters; parameters.rid = layer.rid; parameters.active = !layer.is_paused; result.push_back(parameters); } return result; } RTCError UpdateSimulcastLayerStatusInSender( const std::vector& layers, rtc::scoped_refptr sender) { RTC_DCHECK(sender); RtpParameters parameters = sender->GetParametersInternalWithAllLayers(); std::vector disabled_layers; // The simulcast envelope cannot be changed, only the status of the streams. // So we will iterate over the send encodings rather than the layers. for (RtpEncodingParameters& encoding : parameters.encodings) { auto iter = std::find_if(layers.begin(), layers.end(), [&encoding](const SimulcastLayer& layer) { return layer.rid == encoding.rid; }); // A layer that cannot be found may have been removed by the remote party. if (iter == layers.end()) { disabled_layers.push_back(encoding.rid); continue; } encoding.active = !iter->is_paused; } RTCError result = sender->SetParametersInternalWithAllLayers(parameters); if (result.ok()) { result = sender->DisableEncodingLayers(disabled_layers); } return result; } bool SimulcastIsRejected(const ContentInfo* local_content, const MediaContentDescription& answer_media_desc, bool enable_encrypted_rtp_header_extensions) { bool simulcast_offered = local_content && local_content->media_description() && local_content->media_description()->HasSimulcast(); bool simulcast_answered = answer_media_desc.HasSimulcast(); bool rids_supported = RtpExtension::FindHeaderExtensionByUri( answer_media_desc.rtp_header_extensions(), RtpExtension::kRidUri, enable_encrypted_rtp_header_extensions ? RtpExtension::Filter::kPreferEncryptedExtension : RtpExtension::Filter::kDiscardEncryptedExtension); return simulcast_offered && (!simulcast_answered || !rids_supported); } RTCError DisableSimulcastInSender( rtc::scoped_refptr sender) { RTC_DCHECK(sender); RtpParameters parameters = sender->GetParametersInternalWithAllLayers(); if (parameters.encodings.size() <= 1) { return RTCError::OK(); } std::vector disabled_layers; std::transform( parameters.encodings.begin() + 1, parameters.encodings.end(), std::back_inserter(disabled_layers), [](const RtpEncodingParameters& encoding) { return encoding.rid; }); return sender->DisableEncodingLayers(disabled_layers); } // 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>>& senders, cricket::MediaDescriptionOptions* audio_media_description_options, cricket::MediaDescriptionOptions* video_media_description_options, int num_sim_layers) { for (const auto& 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; } cricket::SenderOptions sender_options; sender_options.track_id = transceiver->sender()->id(); sender_options.stream_ids = transceiver->sender()->stream_ids(); // 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 send_rids; SimulcastLayerList send_layers; for (const RtpEncodingParameters& encoding : send_parameters.encodings) { if (encoding.rid.empty()) { continue; } send_rids.push_back(RidDescription(encoding.rid, RidDirection::kSend)); 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) { return false; } if (current_streams->find(new_stream->id()) != nullptr) { RTC_LOG(LS_ERROR) << "MediaStream with ID " << new_stream->id() << " is already added."; return false; } return true; } rtc::scoped_refptr 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); }); } bool ContentHasHeaderExtension(const cricket::ContentInfo& content_info, absl::string_view header_extension_uri) { for (const RtpExtension& rtp_header_extension : content_info.media_description()->rtp_header_extensions()) { if (rtp_header_extension.uri == header_extension_uri) { return true; } } return false; } } // namespace 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 (const auto& 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 desc, rtc::scoped_refptr observer, std::function 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(-1); InvalidParam("SessionDescription is NULL."); } else { type_ = desc_->GetType(); } } ~RemoteDescriptionOperation() { RTC_DCHECK_RUN_ON(handler_->signaling_thread()); SignalCompletion(); operations_chain_callback_(); } bool ok() const { return error_.ok(); } // Notifies the observer that the operation is complete and releases the // reference to the observer. void SignalCompletion() { if (!observer_) return; if (!error_.ok() && type_ != static_cast(-1)) { std::string error_message = GetSetDescriptionErrorMessage(cricket::CS_REMOTE, type_, error_); RTC_LOG(LS_ERROR) << error_message; error_.set_message(error_message); } 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_); } return false; } if (unified_plan_) { error_ = handler_->Rollback(type_); } else if (type_ == SdpType::kRollback) { Unsupported("Rollback not supported in Plan B"); } return true; } // 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 const auto* existing_remote_description = handler_->remote_description(); #endif error_ = handler_->ReplaceRemoteDescription(std::move(desc_), type_, &replaced_remote_description_); 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"; const auto* remote_description = handler_->remote_description(); const cricket::SessionDescription* session_desc = remote_description->description(); // 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); } return ok(); } bool UpdateSessionState() { RTC_DCHECK(ok()); error_ = handler_->UpdateSessionState( type_, cricket::CS_REMOTE, handler_->remote_description()->description(), bundle_groups_by_mid_); if (!ok()) SetAsSessionError(); return ok(); } bool UseCandidatesInRemoteDescription() { RTC_DCHECK(ok()); if (handler_->local_description() && !handler_->UseCandidatesInRemoteDescription()) { InvalidParam(kInvalidCandidates); } return ok(); } // Convenience getter for desc_->GetType(). SdpType type() const { return type_; } bool unified_plan() const { return unified_plan_; } cricket::SessionDescription* description() { return desc_->description(); } 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& 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)); } void InvalidParam(std::string message) { SetError(RTCErrorType::INVALID_PARAMETER, std::move(message)); } void InternalError(std::string message) { SetError(RTCErrorType::INTERNAL_ERROR, std::move(message)); } void SetError(RTCErrorType type, std::string message) { RTC_DCHECK(ok()) << "Overwriting an existing error?"; error_ = RTCError(type, 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 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 replaced_remote_description_; rtc::scoped_refptr observer_; std::function operations_chain_callback_; RTCError error_ = RTCError::OK(); std::map bundle_groups_by_mid_; SdpType type_; const bool 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 sdp_handler, rtc::scoped_refptr set_local_description_observer) : sdp_handler_(std::move(sdp_handler)), set_local_description_observer_( std::move(set_local_description_observer)) {} ~ImplicitCreateSessionDescriptionObserver() override { RTC_DCHECK(was_called_); } void SetOperationCompleteCallback( std::function operation_complete_callback) { operation_complete_callback_ = std::move(operation_complete_callback); } bool was_called() const { return was_called_; } void OnSuccess(SessionDescriptionInterface* desc_ptr) override { RTC_DCHECK(!was_called_); std::unique_ptr desc(desc_ptr); was_called_ = true; // Abort early if `pc_` is no longer valid. if (!sdp_handler_) { operation_complete_callback_(); return; } // DoSetLocalDescription() is a synchronous operation that invokes // `set_local_description_observer_` with the result. sdp_handler_->DoSetLocalDescription( std::move(desc), std::move(set_local_description_observer_)); operation_complete_callback_(); } void OnFailure(RTCError error) override { RTC_DCHECK(!was_called_); was_called_ = true; set_local_description_observer_->OnSetLocalDescriptionComplete(RTCError( error.type(), std::string("SetLocalDescription failed to create " "session description - ") + error.message())); operation_complete_callback_(); } private: bool was_called_ = false; rtc::WeakPtr sdp_handler_; rtc::scoped_refptr set_local_description_observer_; std::function 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 observer, std::function 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); } void OnFailure(RTCError error) override { #if RTC_DCHECK_IS_ON RTC_DCHECK(!was_called_); was_called_ = true; #endif // RTC_DCHECK_IS_ON operation_complete_callback_(); observer_->OnFailure(std::move(error)); } private: #if RTC_DCHECK_IS_ON bool was_called_ = false; #endif // RTC_DCHECK_IS_ON rtc::scoped_refptr observer_; std::function operation_complete_callback_; }; // Wrapper for SetSessionDescriptionObserver that invokes the success or failure // callback in a posted message handled by the peer connection. This introduces // a delay that prevents recursive API calls by the observer, but this also // means that the PeerConnection can be modified before the observer sees the // result of the operation. This is ill-advised for synchronizing states. // // Implements both the SetLocalDescriptionObserverInterface and the // SetRemoteDescriptionObserverInterface. class SdpOfferAnswerHandler::SetSessionDescriptionObserverAdapter : public SetLocalDescriptionObserverInterface, public SetRemoteDescriptionObserverInterface { public: SetSessionDescriptionObserverAdapter( rtc::WeakPtr handler, rtc::scoped_refptr inner_observer) : handler_(std::move(handler)), inner_observer_(std::move(inner_observer)) {} // SetLocalDescriptionObserverInterface implementation. void OnSetLocalDescriptionComplete(RTCError error) override { OnSetDescriptionComplete(std::move(error)); } // SetRemoteDescriptionObserverInterface implementation. void OnSetRemoteDescriptionComplete(RTCError error) override { OnSetDescriptionComplete(std::move(error)); } private: void OnSetDescriptionComplete(RTCError error) { if (!handler_) return; if (error.ok()) { handler_->pc_->message_handler()->PostSetSessionDescriptionSuccess( inner_observer_.get()); } else { handler_->pc_->message_handler()->PostSetSessionDescriptionFailure( inner_observer_.get(), std::move(error)); } } rtc::WeakPtr handler_; rtc::scoped_refptr inner_observer_; }; class SdpOfferAnswerHandler::LocalIceCredentialsToReplace { public: // Sets the ICE credentials that need restarting to the ICE credentials of // the current and pending descriptions. void SetIceCredentialsFromLocalDescriptions( const SessionDescriptionInterface* current_local_description, const SessionDescriptionInterface* pending_local_description) { ice_credentials_.clear(); if (current_local_description) { AppendIceCredentialsFromSessionDescription(*current_local_description); } if (pending_local_description) { AppendIceCredentialsFromSessionDescription(*pending_local_description); } } void ClearIceCredentials() { ice_credentials_.clear(); } // Returns true if we have ICE credentials that need restarting. bool HasIceCredentials() const { return !ice_credentials_.empty(); } // Returns true if `local_description` shares no ICE credentials with the // ICE credentials that need restarting. bool SatisfiesIceRestart( const SessionDescriptionInterface& local_description) const { for (const auto& transport_info : local_description.description()->transport_infos()) { if (ice_credentials_.find(std::make_pair( transport_info.description.ice_ufrag, transport_info.description.ice_pwd)) != ice_credentials_.end()) { return false; } } return true; } private: void AppendIceCredentialsFromSessionDescription( const SessionDescriptionInterface& desc) { for (const auto& transport_info : desc.description()->transport_infos()) { ice_credentials_.insert( std::make_pair(transport_info.description.ice_ufrag, transport_info.description.ice_pwd)); } } std::set> ice_credentials_; }; SdpOfferAnswerHandler::SdpOfferAnswerHandler(PeerConnectionSdpMethods* pc, ConnectionContext* context) : pc_(pc), context_(context), local_streams_(StreamCollection::Create()), remote_streams_(StreamCollection::Create()), operations_chain_(rtc::OperationsChain::Create()), rtcp_cname_(GenerateRtcpCname()), local_ice_credentials_to_replace_(new LocalIceCredentialsToReplace()), weak_ptr_factory_(this) { operations_chain_->SetOnChainEmptyCallback( [this_weak_ptr = weak_ptr_factory_.GetWeakPtr()]() { if (!this_weak_ptr) return; this_weak_ptr->OnOperationsChainEmpty(); }); } SdpOfferAnswerHandler::~SdpOfferAnswerHandler() {} // Static std::unique_ptr SdpOfferAnswerHandler::Create( PeerConnectionSdpMethods* pc, const PeerConnectionInterface::RTCConfiguration& configuration, PeerConnectionDependencies& dependencies, ConnectionContext* context) { auto handler = absl::WrapUnique(new SdpOfferAnswerHandler(pc, context)); handler->Initialize(configuration, dependencies, context); return handler; } void SdpOfferAnswerHandler::Initialize( const PeerConnectionInterface::RTCConfiguration& configuration, PeerConnectionDependencies& dependencies, ConnectionContext* context) { 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); audio_options_.audio_jitter_buffer_max_packets = configuration.audio_jitter_buffer_max_packets; audio_options_.audio_jitter_buffer_fast_accelerate = configuration.audio_jitter_buffer_fast_accelerate; audio_options_.audio_jitter_buffer_min_delay_ms = configuration.audio_jitter_buffer_min_delay_ms; // Obtain a certificate from RTCConfiguration if any were provided (optional). rtc::scoped_refptr 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]; } webrtc_session_desc_factory_ = std::make_unique( context, this, pc_->session_id(), pc_->dtls_enabled(), std::move(dependencies.cert_generator), std::move(certificate), [this](const rtc::scoped_refptr& certificate) { RTC_DCHECK_RUN_ON(signaling_thread()); transport_controller_s()->SetLocalCertificate(certificate); }, pc_->trials()); if (pc_->options()->disable_encryption) { RTC_LOG(LS_INFO) << "Disabling encryption. This should only be done in tests."; webrtc_session_desc_factory_->SetInsecureForTesting(); } webrtc_session_desc_factory_->set_enable_encrypted_rtp_header_extensions( pc_->GetCryptoOptions().srtp.enable_encrypted_rtp_header_extensions); webrtc_session_desc_factory_->set_is_unified_plan(IsUnifiedPlan()); if (dependencies.video_bitrate_allocator_factory) { video_bitrate_allocator_factory_ = std::move(dependencies.video_bitrate_allocator_factory); } else { video_bitrate_allocator_factory_ = CreateBuiltinVideoBitrateAllocatorFactory(); } } // ================================================================== // Access to pc_ variables cricket::MediaEngineInterface* SdpOfferAnswerHandler::media_engine() const { RTC_DCHECK(context_); return context_->media_engine(); } TransceiverList* SdpOfferAnswerHandler::transceivers() { if (!pc_->rtp_manager()) { return nullptr; } return pc_->rtp_manager()->transceivers(); } const TransceiverList* SdpOfferAnswerHandler::transceivers() const { if (!pc_->rtp_manager()) { return nullptr; } return pc_->rtp_manager()->transceivers(); } JsepTransportController* SdpOfferAnswerHandler::transport_controller_s() { return pc_->transport_controller_s(); } JsepTransportController* SdpOfferAnswerHandler::transport_controller_n() { return pc_->transport_controller_n(); } const JsepTransportController* SdpOfferAnswerHandler::transport_controller_s() const { return pc_->transport_controller_s(); } const JsepTransportController* SdpOfferAnswerHandler::transport_controller_n() const { return pc_->transport_controller_n(); } DataChannelController* SdpOfferAnswerHandler::data_channel_controller() { return pc_->data_channel_controller(); } const DataChannelController* SdpOfferAnswerHandler::data_channel_controller() const { return pc_->data_channel_controller(); } cricket::PortAllocator* SdpOfferAnswerHandler::port_allocator() { return pc_->port_allocator(); } const cricket::PortAllocator* SdpOfferAnswerHandler::port_allocator() const { return pc_->port_allocator(); } RtpTransmissionManager* SdpOfferAnswerHandler::rtp_manager() { return pc_->rtp_manager(); } const RtpTransmissionManager* SdpOfferAnswerHandler::rtp_manager() const { return pc_->rtp_manager(); } // =================================================================== void SdpOfferAnswerHandler::PrepareForShutdown() { RTC_DCHECK_RUN_ON(signaling_thread()); weak_ptr_factory_.InvalidateWeakPtrs(); } void SdpOfferAnswerHandler::Close() { ChangeSignalingState(PeerConnectionInterface::kClosed); } void SdpOfferAnswerHandler::RestartIce() { RTC_DCHECK_RUN_ON(signaling_thread()); local_ice_credentials_to_replace_->SetIceCredentialsFromLocalDescriptions( current_local_description(), pending_local_description()); UpdateNegotiationNeeded(); } rtc::Thread* SdpOfferAnswerHandler::signaling_thread() const { return context_->signaling_thread(); } rtc::Thread* SdpOfferAnswerHandler::network_thread() const { return context_->network_thread(); } void SdpOfferAnswerHandler::CreateOffer( CreateSessionDescriptionObserver* observer, const PeerConnectionInterface::RTCOfferAnswerOptions& options) { RTC_DCHECK_RUN_ON(signaling_thread()); // Chain this operation. If asynchronous operations are pending on the chain, // this operation will be queued to be invoked, otherwise the contents of the // lambda will execute immediately. operations_chain_->ChainOperation( [this_weak_ptr = weak_ptr_factory_.GetWeakPtr(), observer_refptr = rtc::scoped_refptr(observer), options](std::function 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(observer), desc = std::unique_ptr(desc_ptr)]( std::function 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( 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 desc, rtc::scoped_refptr 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 operations_chain_callback) mutable { // Abort early if `this_weak_ptr` is no longer valid. if (!this_weak_ptr) { observer->OnSetLocalDescriptionComplete(RTCError( RTCErrorType::INTERNAL_ERROR, "SetLocalDescription failed because the session was shut down")); operations_chain_callback(); return; } this_weak_ptr->DoSetLocalDescription(std::move(desc), observer); // DoSetLocalDescription() is implemented as a synchronous operation. // The `observer` will already have been informed that it completed, and // we can mark this operation as complete without any loose ends. operations_chain_callback(); }); } void SdpOfferAnswerHandler::SetLocalDescription( SetSessionDescriptionObserver* observer) { RTC_DCHECK_RUN_ON(signaling_thread()); SetLocalDescription( rtc::make_ref_counted( weak_ptr_factory_.GetWeakPtr(), rtc::scoped_refptr(observer))); } void SdpOfferAnswerHandler::SetLocalDescription( rtc::scoped_refptr 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( 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 operations_chain_callback) { // The `create_sdp_observer` is responsible for completing the // operation. create_sdp_observer->SetOperationCompleteCallback( std::move(operations_chain_callback)); // Abort early if `this_weak_ptr` is no longer valid. This triggers the // same code path as if DoCreateOffer() or DoCreateAnswer() failed. if (!this_weak_ptr) { create_sdp_observer->OnFailure(RTCError( RTCErrorType::INTERNAL_ERROR, "SetLocalDescription failed because the session was shut down")); return; } switch (this_weak_ptr->signaling_state()) { case PeerConnectionInterface::kStable: case PeerConnectionInterface::kHaveLocalOffer: case PeerConnectionInterface::kHaveRemotePrAnswer: // TODO(hbos): If [LastCreatedOffer] exists and still represents the // current state of the system, use that instead of creating another // offer. this_weak_ptr->DoCreateOffer( PeerConnectionInterface::RTCOfferAnswerOptions(), create_sdp_observer); break; case PeerConnectionInterface::kHaveLocalPrAnswer: case PeerConnectionInterface::kHaveRemoteOffer: // TODO(hbos): If [LastCreatedAnswer] exists and still represents // the current state of the system, use that instead of creating // another answer. this_weak_ptr->DoCreateAnswer( PeerConnectionInterface::RTCOfferAnswerOptions(), create_sdp_observer); break; case PeerConnectionInterface::kClosed: create_sdp_observer->OnFailure(RTCError( RTCErrorType::INVALID_STATE, "SetLocalDescription called when PeerConnection is closed.")); break; } }); } RTCError SdpOfferAnswerHandler::ApplyLocalDescription( std::unique_ptr desc, const std::map& bundle_groups_by_mid) { TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::ApplyLocalDescription"); RTC_DCHECK_RUN_ON(signaling_thread()); RTC_DCHECK(desc); // 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 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; } } RTCError error = PushdownTransportDescription(cricket::CS_LOCAL, type); if (!error.ok()) { return error; } 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> remove_list; std::vector> removed_streams; for (const auto& 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 (const auto& transceiver : remove_list) { observer->OnRemoveTrack(transceiver->receiver()); } for (const auto& stream : removed_streams) { observer->OnRemoveStream(stream); } } } else { // Media channels will be created only when offer is set. These may use new // transports just created by PushdownTransportDescription. if (type == SdpType::kOffer) { // TODO(bugs.webrtc.org/4676) - Handle CreateChannel failure, as new local // description is applied. Restore back to old description. 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()); } error = UpdateSessionState(type, cricket::CS_LOCAL, local_description()->description(), bundle_groups_by_mid); if (!error.ok()) { RTC_LOG(LS_ERROR) << error.message() << " (" << SdpTypeToString(type) << ")"; return error; } // 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 used_ssrcs; for (const auto& content : local_description()->description()->contents()) { for (const auto& 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 (const auto& 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& 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()); } } const cricket::ContentInfo* video_content = GetFirstVideoContent(local_description()->description()); if (video_content) { if (video_content->rejected) { RemoveSenders(cricket::MEDIA_TYPE_VIDEO); } else { const cricket::MediaContentDescription* video_desc = video_content->media_description(); UpdateLocalSenders(video_desc->streams(), video_desc->type()); } } } // This function does nothing with data content. 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(observer), desc = std::unique_ptr(desc_ptr)]( std::function 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( this_weak_ptr.get(), std::move(desc), rtc::make_ref_counted( this_weak_ptr, observer_refptr), std::move(operations_chain_callback))); }); } void SdpOfferAnswerHandler::SetRemoteDescription( std::unique_ptr desc, rtc::scoped_refptr 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 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; } this_weak_ptr->DoSetRemoteDescription( std::make_unique( this_weak_ptr.get(), std::move(desc), std::move(observer), std::move(operations_chain_callback))); }); } RTCError SdpOfferAnswerHandler::ReplaceRemoteDescription( std::unique_ptr desc, SdpType sdp_type, std::unique_ptr* replaced_description) { RTC_DCHECK(replaced_description); if (sdp_type == SdpType::kAnswer) { *replaced_description = pending_remote_description_ ? std::move(pending_remote_description_) : std::move(current_remote_description_); current_remote_description_ = std::move(desc); pending_remote_description_ = nullptr; current_local_description_ = std::move(pending_local_description_); } else { *replaced_description = std::move(pending_remote_description_); pending_remote_description_ = std::move(desc); } // The session description to apply now must be accessed by // `remote_description()`. const cricket::SessionDescription* session_desc = remote_description()->description(); const auto* 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); } void SdpOfferAnswerHandler::ApplyRemoteDescription( std::unique_ptr operation) { TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::ApplyRemoteDescription"); RTC_DCHECK_RUN_ON(signaling_thread()); RTC_DCHECK(operation->description()); // 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(); SetRemoteDescriptionPostProcess(operation->type() == SdpType::kAnswer); } void SdpOfferAnswerHandler::ApplyRemoteDescriptionUpdateTransceiverState( SdpType sdp_type) { RTC_DCHECK_RUN_ON(signaling_thread()); RTC_DCHECK(IsUnifiedPlan()); if (!ConfiguredForMedia()) { return; } std::vector> now_receiving_transceivers; std::vector> remove_list; std::vector> added_streams; std::vector> removed_streams; for (const auto& transceiver_ext : transceivers()->List()) { const auto 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 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 (const auto& transceiver : now_receiving_transceivers) { pc_->legacy_stats()->AddTrack(transceiver->receiver()->track().get()); observer->OnTrack(transceiver); observer->OnAddTrack(transceiver->receiver(), transceiver->receiver()->streams()); } for (const auto& stream : added_streams) { observer->OnAddStream(stream); } for (const auto& transceiver : remove_list) { observer->OnRemoveTrack(transceiver->receiver()); } for (const auto& stream : removed_streams) { observer->OnRemoveStream(stream); } } void SdpOfferAnswerHandler::PlanBUpdateSendersAndReceivers( const cricket::ContentInfo* audio_content, const cricket::AudioContentDescription* audio_desc, const cricket::ContentInfo* video_content, const cricket::VideoContentDescription* video_desc) { RTC_DCHECK_RUN_ON(signaling_thread()); RTC_DCHECK(!IsUnifiedPlan()); // 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 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(new_stream)); } UpdateEndedRemoteMediaStreams(); } void SdpOfferAnswerHandler::DoSetLocalDescription( std::unique_ptr desc, rtc::scoped_refptr observer) { RTC_DCHECK_RUN_ON(signaling_thread()); TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::DoSetLocalDescription"); if (!observer) { RTC_LOG(LS_ERROR) << "SetLocalDescription - observer is NULL."; return; } if (!desc) { observer->OnSetLocalDescriptionComplete( RTCError(RTCErrorType::INTERNAL_ERROR, "SessionDescription is NULL.")); return; } // If a session error has occurred the PeerConnection is in a possibly // inconsistent state so fail right away. if (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; } std::map bundle_groups_by_mid = GetBundleGroupsByMid(desc->description()); RTCError error = ValidateSessionDescription(desc.get(), cricket::CS_LOCAL, bundle_groups_by_mid); if (!error.ok()) { std::string error_message = GetSetDescriptionErrorMessage( cricket::CS_LOCAL, desc->GetType(), error); RTC_LOG(LS_ERROR) << error_message; observer->OnSetLocalDescriptionComplete( RTCError(error.type(), std::move(error_message))); return; } // Grab the description type before moving ownership to ApplyLocalDescription, // which may destroy it before returning. const SdpType type = desc->GetType(); error = ApplyLocalDescription(std::move(desc), 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(); }); } observer->OnSetLocalDescriptionComplete(RTCError::OK()); pc_->NoteUsageEvent(UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED); // Check if negotiation is needed. We must do this after informing the // observer that SetLocalDescription() has completed to ensure negotiation is // not needed prior to the promise resolving. if (IsUnifiedPlan()) { bool was_negotiation_needed = is_negotiation_needed_; UpdateNegotiationNeeded(); if (signaling_state() == PeerConnectionInterface::kStable && was_negotiation_needed && is_negotiation_needed_) { // Legacy version. pc_->Observer()->OnRenegotiationNeeded(); // Spec-compliant version; the event may get invalidated before firing. GenerateNegotiationNeededEvent(); } } // MaybeStartGathering needs to be called after informing the observer so that // we don't signal any candidates before signaling that SetLocalDescription // completed. transport_controller_s()->MaybeStartGathering(); } void SdpOfferAnswerHandler::DoCreateOffer( const PeerConnectionInterface::RTCOfferAnswerOptions& options, rtc::scoped_refptr observer) { RTC_DCHECK_RUN_ON(signaling_thread()); TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::DoCreateOffer"); if (!observer) { RTC_LOG(LS_ERROR) << "CreateOffer - observer is NULL."; return; } if (pc_->IsClosed()) { std::string error = "CreateOffer called when PeerConnection is closed."; RTC_LOG(LS_ERROR) << error; pc_->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; } } cricket::MediaSessionOptions session_options; GetOptionsForOffer(options, &session_options); webrtc_session_desc_factory_->CreateOffer(observer.get(), options, session_options); } 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(observer), options](std::function 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); }); } void SdpOfferAnswerHandler::DoCreateAnswer( const PeerConnectionInterface::RTCOfferAnswerOptions& options, rtc::scoped_refptr observer) { RTC_DCHECK_RUN_ON(signaling_thread()); TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::DoCreateAnswer"); if (!observer) { RTC_LOG(LS_ERROR) << "CreateAnswer - observer is NULL."; return; } // If a session error has occurred the PeerConnection is in a possibly // inconsistent state so fail right away. if (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."; } } cricket::MediaSessionOptions session_options; GetOptionsForAnswer(options, &session_options); webrtc_session_desc_factory_->CreateAnswer(observer.get(), session_options); } void SdpOfferAnswerHandler::DoSetRemoteDescription( std::unique_ptr operation) { RTC_DCHECK_RUN_ON(signaling_thread()); TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::DoSetRemoteDescription"); if (!operation->ok()) return; if (operation->HaveSessionError()) return; if (operation->MaybeRollback()) return; operation->ReportOfferAnswerUma(); // 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(); }); } pc_->NoteUsageEvent(UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED); // Check if negotiation is needed. We must do this after informing the // observer that SetRemoteDescription() has completed to ensure negotiation // is not needed prior to the promise resolving. if (IsUnifiedPlan()) { bool was_negotiation_needed = is_negotiation_needed_; UpdateNegotiationNeeded(); if (signaling_state() == PeerConnectionInterface::kStable && was_negotiation_needed && is_negotiation_needed_) { // Legacy version. pc_->Observer()->OnRenegotiationNeeded(); // Spec-compliant version; the event may get invalidated before firing. GenerateNegotiationNeededEvent(); } } } void SdpOfferAnswerHandler::SetAssociatedRemoteStreams( rtc::scoped_refptr receiver, const std::vector& stream_ids, std::vector>* added_streams, std::vector>* removed_streams) { RTC_DCHECK_RUN_ON(signaling_thread()); std::vector> media_streams; for (const std::string& stream_id : stream_ids) { rtc::scoped_refptr 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> 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; } AddIceCandidateResult SdpOfferAnswerHandler::AddIceCandidateInternal( const IceCandidateInterface* ice_candidate) { RTC_DCHECK_RUN_ON(signaling_thread()); TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::AddIceCandidate"); if (pc_->IsClosed()) { RTC_LOG(LS_ERROR) << "AddIceCandidate: PeerConnection is closed."; return kAddIceCandidateFailClosed; } if (!remote_description()) { RTC_LOG(LS_ERROR) << "AddIceCandidate: ICE candidates can't be added " "without any remote session description."; return kAddIceCandidateFailNoRemoteDescription; } if (!ice_candidate) { RTC_LOG(LS_ERROR) << "AddIceCandidate: Candidate is null."; return kAddIceCandidateFailNullCandidate; } bool valid = false; bool ready = ReadyToUseRemoteCandidate(ice_candidate, nullptr, &valid); if (!valid) { return kAddIceCandidateFailNotValid; } // 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; } pc_->NoteUsageEvent(UsageEvent::ADD_ICE_CANDIDATE_SUCCEEDED); return kAddIceCandidateSuccess; } void SdpOfferAnswerHandler::AddIceCandidate( std::unique_ptr candidate, std::function 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 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& candidates) { TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::RemoveIceCandidates"); RTC_DCHECK_RUN_ON(signaling_thread()); if (pc_->IsClosed()) { RTC_LOG(LS_ERROR) << "RemoveIceCandidates: PeerConnection is closed."; return false; } if (!remote_description()) { RTC_LOG(LS_ERROR) << "RemoveIceCandidates: ICE candidates can't be removed " "without any remote session description."; return false; } if (candidates.empty()) { RTC_LOG(LS_ERROR) << "RemoveIceCandidates: candidates are empty."; return false; } size_t number_removed = mutable_remote_description()->RemoveCandidates(candidates); if (number_removed != candidates.size()) { RTC_LOG(LS_ERROR) << "RemoveIceCandidates: Failed to remove candidates. Requested " << candidates.size() << " but only " << number_removed << " are removed."; } // Remove the candidates from the transport controller. RTCError error = transport_controller_s()->RemoveRemoteCandidates(candidates); if (!error.ok()) { RTC_LOG(LS_ERROR) << "RemoveIceCandidates: Error when removing remote candidates: " << error.message(); } return true; } void SdpOfferAnswerHandler::AddLocalIceCandidate( const JsepIceCandidate* candidate) { RTC_DCHECK_RUN_ON(signaling_thread()); if (local_description()) { mutable_local_description()->AddCandidate(candidate); } } void SdpOfferAnswerHandler::RemoveLocalIceCandidates( const std::vector& candidates) { RTC_DCHECK_RUN_ON(signaling_thread()); if (local_description()) { mutable_local_description()->RemoveCandidates(candidates); } } const SessionDescriptionInterface* SdpOfferAnswerHandler::local_description() const { RTC_DCHECK_RUN_ON(signaling_thread()); return pending_local_description_ ? pending_local_description_.get() : current_local_description_.get(); } const SessionDescriptionInterface* SdpOfferAnswerHandler::remote_description() const { RTC_DCHECK_RUN_ON(signaling_thread()); return pending_remote_description_ ? pending_remote_description_.get() : current_remote_description_.get(); } const SessionDescriptionInterface* SdpOfferAnswerHandler::current_local_description() const { RTC_DCHECK_RUN_ON(signaling_thread()); return current_local_description_.get(); } const SessionDescriptionInterface* SdpOfferAnswerHandler::current_remote_description() const { RTC_DCHECK_RUN_ON(signaling_thread()); return current_remote_description_.get(); } const SessionDescriptionInterface* SdpOfferAnswerHandler::pending_local_description() const { RTC_DCHECK_RUN_ON(signaling_thread()); return pending_local_description_.get(); } const SessionDescriptionInterface* SdpOfferAnswerHandler::pending_remote_description() const { RTC_DCHECK_RUN_ON(signaling_thread()); return pending_remote_description_.get(); } PeerConnectionInterface::SignalingState SdpOfferAnswerHandler::signaling_state() const { RTC_DCHECK_RUN_ON(signaling_thread()); return signaling_state_; } void SdpOfferAnswerHandler::ChangeSignalingState( PeerConnectionInterface::SignalingState signaling_state) { TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::ChangeSignalingState"); RTC_DCHECK_RUN_ON(signaling_thread()); if (signaling_state_ == signaling_state) { return; } RTC_LOG(LS_INFO) << "Session: " << pc_->session_id() << " Old state: " << PeerConnectionInterface::AsString(signaling_state_) << " New state: " << PeerConnectionInterface::AsString(signaling_state); signaling_state_ = signaling_state; pc_->Observer()->OnSignalingChange(signaling_state_); } RTCError SdpOfferAnswerHandler::UpdateSessionState( SdpType type, cricket::ContentSource source, const cricket::SessionDescription* description, const std::map& bundle_groups_by_mid) { RTC_DCHECK_RUN_ON(signaling_thread()); // If there's already a pending error then no state transition should // happen. But all call-sites should be verifying this before calling us! RTC_DCHECK(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); } else if (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()) { return true; } // The event ID has been invalidated. Either negotiation is no longer needed // or a newer negotiation needed event has been generated. if (event_id != negotiation_needed_event_id_) { return false; } // The chain is no longer empty, update negotiation needed when it becomes // empty. This should generate a newer negotiation needed event, making this // one obsolete. if (!operations_chain_->IsEmpty()) { // Since we just suppressed an event that would have been fired, if // negotiation is still needed by the time the chain becomes empty again, // we must make sure to generate another event if negotiation is needed // then. This happens when `is_negotiation_needed_` goes from false to // true, so we set it to false until UpdateNegotiationNeeded() is called. is_negotiation_needed_ = false; update_negotiation_needed_on_empty_chain_ = true; return false; } // We must not fire if the signaling state is no longer "stable". If // negotiation is still needed when we return to "stable", a new negotiation // needed event will be generated, so this one can safely be suppressed. if (signaling_state_ != PeerConnectionInterface::kStable) { return false; } // All checks have passed - please fire "negotiationneeded" now! return true; } rtc::scoped_refptr 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 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()) { return false; } if (!CanAddLocalMediaStream(local_streams_.get(), local_stream)) { return false; } local_streams_->AddStream( rtc::scoped_refptr(local_stream)); auto observer = std::make_unique( local_stream, [this](AudioTrackInterface* audio_track, MediaStreamInterface* media_stream) { RTC_DCHECK_RUN_ON(signaling_thread()); OnAudioTrackAdded(audio_track, media_stream); }, [this](AudioTrackInterface* audio_track, MediaStreamInterface* media_stream) { RTC_DCHECK_RUN_ON(signaling_thread()); OnAudioTrackRemoved(audio_track, media_stream); }, [this](VideoTrackInterface* video_track, MediaStreamInterface* media_stream) { RTC_DCHECK_RUN_ON(signaling_thread()); OnVideoTrackAdded(video_track, media_stream); }, [this](VideoTrackInterface* video_track, MediaStreamInterface* media_stream) { RTC_DCHECK_RUN_ON(signaling_thread()); OnVideoTrackRemoved(video_track, media_stream); }); stream_observers_.push_back(std::move(observer)); for (const auto& track : local_stream->GetAudioTracks()) { rtp_manager()->AddAudioTrack(track.get(), local_stream); } for (const auto& track : local_stream->GetVideoTracks()) { rtp_manager()->AddVideoTrack(track.get(), local_stream); } pc_->legacy_stats()->AddStream(local_stream); UpdateNegotiationNeeded(); return true; } void SdpOfferAnswerHandler::RemoveStream(MediaStreamInterface* local_stream) { RTC_DCHECK_RUN_ON(signaling_thread()); RTC_CHECK(!IsUnifiedPlan()) << "RemoveStream is not available with Unified " "Plan SdpSemantics. Please use RemoveTrack " "instead."; TRACE_EVENT0("webrtc", "PeerConnection::RemoveStream"); if (!pc_->IsClosed()) { for (const auto& track : local_stream->GetAudioTracks()) { rtp_manager()->RemoveAudioTrack(track.get(), local_stream); } for (const auto& track : local_stream->GetVideoTracks()) { rtp_manager()->RemoveVideoTrack(track.get(), local_stream); } } local_streams_->RemoveStream(local_stream); stream_observers_.erase( std::remove_if( stream_observers_.begin(), stream_observers_.end(), [local_stream](const std::unique_ptr& observer) { return observer->stream()->id().compare(local_stream->id()) == 0; }), stream_observers_.end()); if (pc_->IsClosed()) { return; } UpdateNegotiationNeeded(); } void SdpOfferAnswerHandler::OnAudioTrackAdded(AudioTrackInterface* track, MediaStreamInterface* stream) { if (pc_->IsClosed()) { return; } rtp_manager()->AddAudioTrack(track, stream); UpdateNegotiationNeeded(); } void SdpOfferAnswerHandler::OnAudioTrackRemoved(AudioTrackInterface* track, MediaStreamInterface* stream) { if (pc_->IsClosed()) { return; } rtp_manager()->RemoveAudioTrack(track, stream); UpdateNegotiationNeeded(); } void SdpOfferAnswerHandler::OnVideoTrackAdded(VideoTrackInterface* track, MediaStreamInterface* stream) { if (pc_->IsClosed()) { return; } rtp_manager()->AddVideoTrack(track, stream); UpdateNegotiationNeeded(); } void SdpOfferAnswerHandler::OnVideoTrackRemoved(VideoTrackInterface* track, MediaStreamInterface* stream) { if (pc_->IsClosed()) { return; } rtp_manager()->RemoveVideoTrack(track, stream); UpdateNegotiationNeeded(); } 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> now_receiving_transceivers; std::vector> all_added_streams; std::vector> all_removed_streams; std::vector> 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()); } if (state.remote_stream_ids()) { std::vector> added_streams; std::vector> removed_streams; SetAssociatedRemoteStreams(transceiver->internal()->receiver_internal(), state.remote_stream_ids().value(), &added_streams, &removed_streams); all_added_streams.insert(all_added_streams.end(), added_streams.begin(), added_streams.end()); all_removed_streams.insert(all_removed_streams.end(), removed_streams.begin(), removed_streams.end()); if (!state.has_m_section() && !state.newly_created()) { continue; } } // 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. RTC_DCHECK(transceiver->internal()->mid().has_value()); transceiver->internal()->ClearChannel(); 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 (const auto& transceiver : now_receiving_transceivers) { pc_->Observer()->OnTrack(transceiver); pc_->Observer()->OnAddTrack(transceiver->receiver(), transceiver->receiver()->streams()); } for (const auto& receiver : removed_receivers) { pc_->Observer()->OnRemoveTrack(receiver); } for (const auto& stream : all_added_streams) { pc_->Observer()->OnAddStream(stream); } for (const auto& stream : all_removed_streams) { pc_->Observer()->OnRemoveStream(stream); } // The assumption is that in case of implicit rollback // UpdateNegotiationNeeded gets called in SetRemoteDescription. if (desc_type == SdpType::kRollback) { UpdateNegotiationNeeded(); if (is_negotiation_needed_) { // Legacy version. pc_->Observer()->OnRenegotiationNeeded(); // Spec-compliant version; the event may get invalidated before firing. GenerateNegotiationNeededEvent(); } } return RTCError::OK(); } bool SdpOfferAnswerHandler::IsUnifiedPlan() const { return pc_->IsUnifiedPlan(); } void SdpOfferAnswerHandler::OnOperationsChainEmpty() { RTC_DCHECK_RUN_ON(signaling_thread()); if (pc_->IsClosed() || !update_negotiation_needed_on_empty_chain_) return; update_negotiation_needed_on_empty_chain_ = false; // Firing when chain is empty is only supported in Unified Plan to avoid // Plan B regressions. (In Plan B, onnegotiationneeded is already broken // anyway, so firing it even more might just be confusing.) if (IsUnifiedPlan()) { UpdateNegotiationNeeded(); } } absl::optional SdpOfferAnswerHandler::is_caller() const { RTC_DCHECK_RUN_ON(signaling_thread()); return is_caller_; } bool SdpOfferAnswerHandler::HasNewIceCredentials() { RTC_DCHECK_RUN_ON(signaling_thread()); return local_ice_credentials_to_replace_->HasIceCredentials(); } bool SdpOfferAnswerHandler::IceRestartPending( const std::string& content_name) const { RTC_DCHECK_RUN_ON(signaling_thread()); return pending_ice_restarts_.find(content_name) != pending_ice_restarts_.end(); } bool SdpOfferAnswerHandler::NeedsIceRestart( const std::string& content_name) const { return pc_->NeedsIceRestart(content_name); } absl::optional SdpOfferAnswerHandler::GetDtlsRole( const std::string& mid) const { RTC_DCHECK_RUN_ON(signaling_thread()); return transport_controller_s()->GetDtlsRole(mid); } void SdpOfferAnswerHandler::UpdateNegotiationNeeded() { RTC_DCHECK_RUN_ON(signaling_thread()); if (!IsUnifiedPlan()) { pc_->Observer()->OnRenegotiationNeeded(); GenerateNegotiationNeededEvent(); return; } // In the spec, a task is queued here to run the following steps - this is // meant to ensure we do not fire onnegotiationneeded prematurely if // multiple changes are being made at once. In order to support Chromium's // implementation where the JavaScript representation of the PeerConnection // lives on a separate thread though, the queuing of a task is instead // performed by the PeerConnectionObserver posting from the signaling thread // to the JavaScript main thread that negotiation is needed. And because the // Operations Chain lives on the WebRTC signaling thread, // ShouldFireNegotiationNeededEvent() must be called before firing the event // to ensure the Operations Chain is still empty and the event has not been // invalidated. // If connection's [[IsClosed]] slot is true, abort these steps. if (pc_->IsClosed()) return; // If connection's signaling state is not "stable", abort these steps. if (signaling_state() != PeerConnectionInterface::kStable) return; // NOTE // The negotiation-needed flag will be updated once the state transitions to // "stable", as part of the steps for setting an RTCSessionDescription. // If the result of checking if negotiation is needed is false, clear the // negotiation-needed flag by setting connection's [[NegotiationNeeded]] // slot to false, and abort these steps. bool is_negotiation_needed = CheckIfNegotiationIsNeeded(); if (!is_negotiation_needed) { is_negotiation_needed_ = false; // Invalidate any negotiation needed event that may previosuly have been // generated. ++negotiation_needed_event_id_; return; } // If connection's [[NegotiationNeeded]] slot is already true, abort these // steps. if (is_negotiation_needed_) return; // Set connection's [[NegotiationNeeded]] slot to true. is_negotiation_needed_ = true; // Queue a task that runs the following steps: // If connection's [[IsClosed]] slot is true, abort these steps. // If connection's [[NegotiationNeeded]] slot is false, abort these steps. // Fire an event named negotiationneeded at connection. pc_->Observer()->OnRenegotiationNeeded(); // Fire the spec-compliant version; when ShouldFireNegotiationNeededEvent() // is used in the task queued by the observer, this event will only fire // when the chain is empty. GenerateNegotiationNeededEvent(); } 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; } absl::optional guessed_role = GuessSslRole(); network_thread()->BlockingCall( [&, data_channel_controller = data_channel_controller()] { RTC_DCHECK_RUN_ON(network_thread()); absl::optional role = pc_->GetSctpSslRole_n(); if (!role) role = guessed_role; if (role) data_channel_controller->AllocateSctpSids(*role); }); } absl::optional SdpOfferAnswerHandler::GuessSslRole() const { RTC_DCHECK_RUN_ON(signaling_thread()); if (!pc_->sctp_mid()) return absl::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. return is_caller() ? rtc::SSL_SERVER : rtc::SSL_CLIENT; } bool SdpOfferAnswerHandler::CheckIfNegotiationIsNeeded() { RTC_DCHECK_RUN_ON(signaling_thread()); // 1. If any implementation-specific negotiation is required, as described // at the start of this section, return true. // 2. If connection.[[LocalIceCredentialsToReplace]] is not empty, return // true. if (local_ice_credentials_to_replace_->HasIceCredentials()) { return true; } // 3. Let description be connection.[[CurrentLocalDescription]]. const SessionDescriptionInterface* description = current_local_description(); if (!description) return true; // 4. If connection has created any RTCDataChannels, and no m= section in // description has been negotiated yet for data, return true. if (data_channel_controller()->HasUsedDataChannels()) { const cricket::ContentInfo* data_content = cricket::GetFirstDataContent(description->description()->contents()); if (!data_content) { return true; } // 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) { return true; } } if (!ConfiguredForMedia()) { return false; } // 5. For each transceiver in connection's set of transceivers, perform the // following checks: for (const auto& transceiver : transceivers()->ListInternal()) { const ContentInfo* current_local_msection = FindTransceiverMSection(transceiver, description); const ContentInfo* current_remote_msection = FindTransceiverMSection(transceiver, current_remote_description()); // 5.4 If transceiver is stopped and is associated with an m= section, // but the associated m= section is not yet rejected in // connection.[[CurrentLocalDescription]] or // connection.[[CurrentRemoteDescription]], return true. if (transceiver->stopped()) { RTC_DCHECK(transceiver->stopping()); if (current_local_msection && !current_local_msection->rejected && ((current_remote_msection && !current_remote_msection->rejected) || !current_remote_msection)) { return true; } continue; } // 5.1 If transceiver.[[Stopping]] is true and transceiver.[[Stopped]] is // false, return true. if (transceiver->stopping() && !transceiver->stopped()) return true; // 5.2 If transceiver isn't stopped and isn't yet associated with an m= // section in description, return true. if (!current_local_msection) return true; const MediaContentDescription* current_local_media_description = current_local_msection->media_description(); // 5.3 If transceiver isn't stopped and is associated with an m= section // in description then perform the following checks: // 5.3.1 If transceiver.[[Direction]] is "sendrecv" or "sendonly", and the // associated m= section in description either doesn't contain a single // "a=msid" line, or the number of MSIDs from the "a=msid" lines in this // m= section, or the MSID values themselves, differ from what is in // transceiver.sender.[[AssociatedMediaStreamIds]], return true. if (RtpTransceiverDirectionHasSend(transceiver->direction())) { if (current_local_media_description->streams().size() == 0) return true; std::vector msection_msids; for (const auto& stream : current_local_media_description->streams()) { for (const std::string& msid : stream.stream_ids()) msection_msids.push_back(msid); } std::vector transceiver_msids = transceiver->sender()->stream_ids(); if (msection_msids.size() != transceiver_msids.size()) return true; absl::c_sort(transceiver_msids); absl::c_sort(msection_msids); if (transceiver_msids != msection_msids) return true; } // 5.3.2 If description is of type "offer", and the direction of the // associated m= section in neither connection.[[CurrentLocalDescription]] // nor connection.[[CurrentRemoteDescription]] matches // transceiver.[[Direction]], return true. if (description->GetType() == SdpType::kOffer) { if (!current_remote_description()) return true; if (!current_remote_msection) return true; RtpTransceiverDirection current_local_direction = current_local_media_description->direction(); RtpTransceiverDirection current_remote_direction = current_remote_msection->media_description()->direction(); if (transceiver->direction() != current_local_direction && transceiver->direction() != RtpTransceiverDirectionReversed(current_remote_direction)) { return true; } } // 5.3.3 If description is of type "answer", and the direction of the // associated m= section in the description does not match // transceiver.[[Direction]] intersected with the offered direction (as // described in [JSEP] (section 5.3.1.)), return true. if (description->GetType() == SdpType::kAnswer) { if (!remote_description()) return true; const ContentInfo* offered_remote_msection = FindTransceiverMSection(transceiver, remote_description()); RtpTransceiverDirection offered_direction = offered_remote_msection ? offered_remote_msection->media_description()->direction() : RtpTransceiverDirection::kInactive; if (current_local_media_description->direction() != (RtpTransceiverDirectionIntersection( transceiver->direction(), RtpTransceiverDirectionReversed(offered_direction)))) { return true; } } } // If all the preceding checks were performed and true was not returned, // nothing remains to be negotiated; return false. return false; } void SdpOfferAnswerHandler::GenerateNegotiationNeededEvent() { RTC_DCHECK_RUN_ON(signaling_thread()); ++negotiation_needed_event_id_; pc_->Observer()->OnNegotiationNeededEvent(negotiation_needed_event_id_); } RTCError SdpOfferAnswerHandler::ValidateSessionDescription( const SessionDescriptionInterface* sdesc, cricket::ContentSource source, const std::map& 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 crypto settings. std::string crypto_error; if (pc_->dtls_enabled()) { RTCError crypto_error = VerifyCrypto( sdesc->description(), pc_->dtls_enabled(), bundle_groups_by_mid); if (!crypto_error.ok()) { return crypto_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; } // TODO(crbug.com/1459124): remove killswitch after rollout. error = ValidateSsrcGroups(*sdesc->description()); if (!error.ok() && !pc_->trials().IsDisabled("WebRTC-PreventSsrcGroupsWithUnexpectedSize")) { 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(); } } else if (remote_description()) { current_desc = remote_description()->description(); } if (current_desc && !MediaSectionsInSameOrder(*current_desc, secondary_current_desc, *sdesc->description(), type)) { LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, kMlineMismatchInSubsequentOffer); } } if (IsUnifiedPlan()) { // Ensure that each audio and video media section has at most one // "StreamParams". This will return an error if receiving a session // description from a "Plan B" endpoint which adds multiple tracks of the // same type. With Unified Plan, there can only be at most one track per // media section. for (const ContentInfo& content : sdesc->description()->contents()) { const MediaContentDescription& desc = *content.media_description(); if ((desc.type() == cricket::MEDIA_TYPE_AUDIO || desc.type() == cricket::MEDIA_TYPE_VIDEO) && desc.streams().size() > 1u) { LOG_AND_RETURN_ERROR( RTCErrorType::INVALID_PARAMETER, "Media section has more than one track specified with a=ssrc lines " "which is not supported with Unified Plan."); } } // 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; } } return RTCError::OK(); } RTCError SdpOfferAnswerHandler::UpdateTransceiversAndDataChannels( cricket::ContentSource source, const SessionDescriptionInterface& new_session, const SessionDescriptionInterface* old_local_description, const SessionDescriptionInterface* old_remote_description, const std::map& bundle_groups_by_mid) { TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::UpdateTransceiversAndDataChannels"); RTC_DCHECK_RUN_ON(signaling_thread()); RTC_DCHECK(IsUnifiedPlan()); 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; } } else if (media_type == cricket::MEDIA_TYPE_DATA) { const auto 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; } } else if (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>> 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 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 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); } RTCError SdpOfferAnswerHandler::UpdateTransceiverChannel( rtc::scoped_refptr> transceiver, const cricket::ContentInfo& content, const cricket::ContentGroup* bundle_group) { TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::UpdateTransceiverChannel"); RTC_DCHECK(IsUnifiedPlan()); RTC_DCHECK(transceiver); cricket::ChannelInterface* channel = transceiver->internal()->channel(); if (content.rejected) { if (channel) { transceiver->internal()->ClearChannel(); } } else { if (!channel) { auto error = transceiver->internal()->CreateChannel( content.name, pc_->call_ptr(), pc_->configuration()->media_config, pc_->SrtpRequired(), pc_->GetCryptoOptions(), audio_options(), video_options(), video_bitrate_allocator_factory_.get(), [&](absl::string_view mid) { RTC_DCHECK_RUN_ON(network_thread()); return transport_controller_n()->GetRtpTransport(mid); }); if (!error.ok()) { return error; } } } return RTCError::OK(); } RTCError SdpOfferAnswerHandler::UpdateDataChannelTransport( cricket::ContentSource source, const cricket::ContentInfo& content, const cricket::ContentGroup* bundle_group) { if (content.rejected) { RTC_LOG(LS_INFO) << "Rejected data channel transport with mid=" << content.mid(); rtc::StringBuilder sb; sb << "Rejected data channel transport with mid=" << content.mid(); RTCError error(RTCErrorType::OPERATION_ERROR_WITH_DATA, sb.Release()); error.set_error_detail(RTCErrorDetailType::DATA_CHANNEL_FAILURE); pc_->DestroyDataChannelTransport(error); } else if (!pc_->CreateDataChannelTransport(content.name)) { LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR, "Failed to create data channel."); } return RTCError::OK(); } bool SdpOfferAnswerHandler::ExpectSetLocalDescription(SdpType type) { PeerConnectionInterface::SignalingState state = signaling_state(); if (type == SdpType::kOffer) { return (state == PeerConnectionInterface::kStable) || (state == PeerConnectionInterface::kHaveLocalOffer); } else { RTC_DCHECK(type == SdpType::kPrAnswer || type == SdpType::kAnswer); return (state == PeerConnectionInterface::kHaveRemoteOffer) || (state == PeerConnectionInterface::kHaveLocalPrAnswer); } } bool SdpOfferAnswerHandler::ExpectSetRemoteDescription(SdpType type) { PeerConnectionInterface::SignalingState state = signaling_state(); if (type == SdpType::kOffer) { return (state == PeerConnectionInterface::kStable) || (state == PeerConnectionInterface::kHaveRemoteOffer); } else { RTC_DCHECK(type == SdpType::kPrAnswer || type == SdpType::kAnswer); return (state == PeerConnectionInterface::kHaveLocalOffer) || (state == PeerConnectionInterface::kHaveRemotePrAnswer); } } 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"; } else if (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> 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()); } } void SdpOfferAnswerHandler::GetOptionsForOffer( const PeerConnectionInterface::RTCOfferAnswerOptions& offer_answer_options, cricket::MediaSessionOptions* session_options) { RTC_DCHECK_RUN_ON(signaling_thread()); ExtractSharedMediaSessionOptions(offer_answer_options, session_options); if (IsUnifiedPlan()) { GetOptionsForUnifiedPlanOffer(offer_answer_options, session_options); } else { GetOptionsForPlanBOffer(offer_answer_options, session_options); } // Apply ICE restart flag and renomination flag. bool ice_restart = offer_answer_options.ice_restart || HasNewIceCredentials(); for (auto& options : session_options->media_description_options) { options.transport_options.ice_restart = ice_restart; options.transport_options.enable_ice_renomination = pc_->configuration()->enable_ice_renomination; } session_options->rtcp_cname = rtcp_cname_; session_options->crypto_options = pc_->GetCryptoOptions(); session_options->pooled_ice_credentials = context_->network_thread()->BlockingCall( [this] { return port_allocator()->GetPooledIceCredentials(); }); session_options->offer_extmap_allow_mixed = pc_->configuration()->offer_extmap_allow_mixed; // 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; } void SdpOfferAnswerHandler::GetOptionsForPlanBOffer( const PeerConnectionInterface::RTCOfferAnswerOptions& offer_answer_options, cricket::MediaSessionOptions* session_options) { bool offer_new_data_description = data_channel_controller()->HasUsedDataChannels(); bool send_audio = false; bool send_video = false; bool recv_audio = false; bool recv_video = false; 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. 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); } } absl::optional audio_index; absl::optional video_index; absl::optional 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); } if (ConfiguredForMedia()) { // Add audio/video/data m= sections to the end if needed. if (!audio_index && offer_new_audio_description) { cricket::MediaDescriptionOptions options( cricket::MEDIA_TYPE_AUDIO, cricket::CN_AUDIO, RtpTransceiverDirectionFromSendRecv(send_audio, recv_audio), false); options.header_extensions = media_engine()->voice().GetRtpHeaderExtensions(); session_options->media_description_options.push_back(options); audio_index = session_options->media_description_options.size() - 1; } if (!video_index && offer_new_video_description) { cricket::MediaDescriptionOptions options( cricket::MEDIA_TYPE_VIDEO, cricket::CN_VIDEO, RtpTransceiverDirectionFromSendRecv(send_video, recv_video), false); options.header_extensions = media_engine()->video().GetRtpHeaderExtensions(); session_options->media_description_options.push_back(options); video_index = session_options->media_description_options.size() - 1; } cricket::MediaDescriptionOptions* audio_media_description_options = !audio_index ? nullptr : &session_options->media_description_options[*audio_index]; cricket::MediaDescriptionOptions* video_media_description_options = !video_index ? nullptr : &session_options->media_description_options[*video_index]; AddPlanBRtpSenderOptions(rtp_manager()->GetSendersInternal(), audio_media_description_options, video_media_description_options, offer_answer_options.num_simulcast_layers); } if (!data_index && offer_new_data_description) { session_options->media_description_options.push_back( GetMediaDescriptionOptionsForActiveData(cricket::CN_DATA)); } } 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 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); } } } else if (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 { const auto 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 (const auto& 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())); } } } void SdpOfferAnswerHandler::GetOptionsForAnswer( const RTCOfferAnswerOptions& offer_answer_options, cricket::MediaSessionOptions* session_options) { RTC_DCHECK_RUN_ON(signaling_thread()); ExtractSharedMediaSessionOptions(offer_answer_options, session_options); if (IsUnifiedPlan()) { GetOptionsForUnifiedPlanAnswer(offer_answer_options, session_options); } else { GetOptionsForPlanBAnswer(offer_answer_options, session_options); } // Apply ICE renomination flag. for (auto& options : session_options->media_description_options) { options.transport_options.enable_ice_renomination = pc_->configuration()->enable_ice_renomination; } session_options->rtcp_cname = rtcp_cname_; session_options->crypto_options = pc_->GetCryptoOptions(); session_options->pooled_ice_credentials = context_->network_thread()->BlockingCall( [this] { return port_allocator()->GetPooledIceCredentials(); }); } void SdpOfferAnswerHandler::GetOptionsForPlanBAnswer( const PeerConnectionInterface::RTCOfferAnswerOptions& offer_answer_options, cricket::MediaSessionOptions* session_options) { bool send_audio = false; bool recv_audio = false; bool send_video = false; bool recv_video = false; 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); } } absl::optional audio_index; absl::optional video_index; absl::optional data_index; // 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); cricket::MediaDescriptionOptions* audio_media_description_options = !audio_index ? nullptr : &session_options->media_description_options[*audio_index]; cricket::MediaDescriptionOptions* video_media_description_options = !video_index ? nullptr : &session_options->media_description_options[*video_index]; 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)); } } else if (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)); } } } } const char* 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 ""; } std::string SdpOfferAnswerHandler::GetSessionErrorMsg() { RTC_DCHECK_RUN_ON(signaling_thread()); rtc::StringBuilder desc; desc << kSessionError << SessionErrorToString(session_error()) << ". "; desc << kSessionErrorDesc << session_error_desc() << "."; return desc.Release(); } void SdpOfferAnswerHandler::SetSessionError(SessionError error, const std::string& error_desc) { RTC_DCHECK_RUN_ON(signaling_thread()); if (error != session_error_) { session_error_ = error; session_error_desc_ = error_desc; } } RTCError SdpOfferAnswerHandler::HandleLegacyOfferOptions( const PeerConnectionInterface::RTCOfferAnswerOptions& options) { RTC_DCHECK_RUN_ON(signaling_thread()); RTC_DCHECK(IsUnifiedPlan()); if (options.offer_to_receive_audio == 0) { RemoveRecvDirectionFromReceivingTransceiversOfType( cricket::MEDIA_TYPE_AUDIO); } else if (options.offer_to_receive_audio == 1) { AddUpToOneReceivingTransceiverOfType(cricket::MEDIA_TYPE_AUDIO); } else if (options.offer_to_receive_audio > 1) { LOG_AND_RETURN_ERROR(RTCErrorType::UNSUPPORTED_PARAMETER, "offer_to_receive_audio > 1 is not supported."); } if (options.offer_to_receive_video == 0) { RemoveRecvDirectionFromReceivingTransceiversOfType( cricket::MEDIA_TYPE_VIDEO); } else if (options.offer_to_receive_video == 1) { AddUpToOneReceivingTransceiverOfType(cricket::MEDIA_TYPE_VIDEO); } else if (options.offer_to_receive_video > 1) { LOG_AND_RETURN_ERROR(RTCErrorType::UNSUPPORTED_PARAMETER, "offer_to_receive_video > 1 is not supported."); } return RTCError::OK(); } void SdpOfferAnswerHandler::RemoveRecvDirectionFromReceivingTransceiversOfType( cricket::MediaType media_type) { for (const auto& transceiver : GetReceivingTransceiversOfType(media_type)) { RtpTransceiverDirection new_direction = RtpTransceiverDirectionWithRecvSet(transceiver->direction(), false); if (new_direction != transceiver->direction()) { RTC_LOG(LS_INFO) << "Changing " << cricket::MediaTypeToString(media_type) << " transceiver (MID=" << transceiver->mid().value_or("") << ") from " << RtpTransceiverDirectionToString( transceiver->direction()) << " to " << RtpTransceiverDirectionToString(new_direction) << " since CreateOffer specified offer_to_receive=0"; transceiver->internal()->set_direction(new_direction); } } } void SdpOfferAnswerHandler::AddUpToOneReceivingTransceiverOfType( cricket::MediaType media_type) { RTC_DCHECK_RUN_ON(signaling_thread()); if (GetReceivingTransceiversOfType(media_type).empty()) { RTC_LOG(LS_INFO) << "Adding one recvonly " << cricket::MediaTypeToString(media_type) << " transceiver since CreateOffer specified offer_to_receive=1"; RtpTransceiverInit init; init.direction = RtpTransceiverDirection::kRecvOnly; pc_->AddTransceiver(media_type, nullptr, init, /*update_negotiation_needed=*/false); } } std::vector>> SdpOfferAnswerHandler::GetReceivingTransceiversOfType( cricket::MediaType media_type) { std::vector< rtc::scoped_refptr>> receiving_transceivers; for (const auto& transceiver : transceivers()->List()) { if (!transceiver->stopped() && transceiver->media_type() == media_type && RtpTransceiverDirectionHasRecv(transceiver->direction())) { receiving_transceivers.push_back(transceiver); } } return receiving_transceivers; } void SdpOfferAnswerHandler::ProcessRemovalOfRemoteTrack( rtc::scoped_refptr> transceiver, std::vector>* remove_list, std::vector>* removed_streams) { RTC_DCHECK(transceiver->mid()); RTC_LOG(LS_INFO) << "Processing the removal of a track for MID=" << *transceiver->mid(); std::vector> 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>& remote_streams, std::vector>* 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 (const auto& 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); } } } void SdpOfferAnswerHandler::RemoveSenders(cricket::MediaType media_type) { RTC_DCHECK_RUN_ON(signaling_thread()); UpdateLocalSenders(std::vector(), media_type); UpdateRemoteSendersList(std::vector(), false, media_type, nullptr); } void SdpOfferAnswerHandler::UpdateLocalSenders( const std::vector& streams, cricket::MediaType media_type) { TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::UpdateLocalSenders"); RTC_DCHECK_RUN_ON(signaling_thread()); std::vector* current_senders = rtp_manager()->GetLocalSenderInfos(media_type); // 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); } } } void SdpOfferAnswerHandler::UpdateRemoteSendersList( const cricket::StreamParamsVec& streams, bool default_sender_needed, cricket::MediaType media_type, StreamCollection* new_streams) { TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::UpdateRemoteSendersList"); RTC_DCHECK_RUN_ON(signaling_thread()); RTC_DCHECK(!IsUnifiedPlan()); std::vector* current_senders = rtp_manager()->GetRemoteSenderInfos(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 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); } 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()->OnRemoteSenderAdded(current_senders->back(), stream.get(), media_type); } } // Add default sender if necessary. if (default_sender_needed) { rtc::scoped_refptr default_stream( remote_streams_->find(kDefaultStreamId)); if (!default_stream) { // Create the new default MediaStream. default_stream = MediaStreamProxy::Create( rtc::Thread::Current(), MediaStream::Create(kDefaultStreamId)); remote_streams_->AddStream(default_stream); new_streams->AddStream(default_stream); } std::string default_sender_id = (media_type == cricket::MEDIA_TYPE_AUDIO) ? kDefaultAudioSenderId : kDefaultVideoSenderId; const RtpSenderInfo* default_sender_info = rtp_manager()->FindSenderInfo( *current_senders, kDefaultStreamId, default_sender_id); if (!default_sender_info) { current_senders->push_back( RtpSenderInfo(kDefaultStreamId, default_sender_id, /*ssrc=*/0)); rtp_manager()->OnRemoteSenderAdded(current_senders->back(), default_stream.get(), media_type); } } } void SdpOfferAnswerHandler::EnableSending() { TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::EnableSending"); RTC_DCHECK_RUN_ON(signaling_thread()); if (!ConfiguredForMedia()) { return; } for (const auto& transceiver : transceivers()->ListInternal()) { cricket::ChannelInterface* channel = transceiver->channel(); if (channel) { channel->Enable(true); } } } RTCError SdpOfferAnswerHandler::PushdownMediaDescription( SdpType type, cricket::ContentSource source, const std::map& bundle_groups_by_mid) { TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::PushdownMediaDescription"); const SessionDescriptionInterface* sdesc = (source == cricket::CS_LOCAL ? local_description() : remote_description()); RTC_DCHECK_RUN_ON(signaling_thread()); RTC_DCHECK(sdesc); 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> channels; for (const auto& 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; } transceiver->OnNegotiationUpdate(type, content_desc); channels.push_back(std::make_pair(channel, content_desc)); } // 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 (const auto& 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); } } return RTCError::OK(); } RTCError SdpOfferAnswerHandler::PushdownTransportDescription( cricket::ContentSource source, SdpType type) { TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::PushdownTransportDescription"); RTC_DCHECK_RUN_ON(signaling_thread()); if (source == cricket::CS_LOCAL) { const SessionDescriptionInterface* sdesc = local_description(); RTC_DCHECK(sdesc); const auto* remote = remote_description(); return transport_controller_s()->SetLocalDescription( type, sdesc->description(), remote ? remote->description() : nullptr); } else { const SessionDescriptionInterface* sdesc = remote_description(); RTC_DCHECK(sdesc); const auto* local = local_description(); return transport_controller_s()->SetRemoteDescription( type, local ? local->description() : nullptr, sdesc->description()); } } 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(absl::nullopt); transceiver->internal()->set_mline_index(absl::nullopt); } else if (!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); } else if (data_info->rejected) { rtc::StringBuilder sb; sb << "Rejected data channel with mid=" << data_info->name << "."; RTCError error(RTCErrorType::OPERATION_ERROR_WITH_DATA, sb.Release()); error.set_error_detail(RTCErrorDetailType::DATA_CHANNEL_FAILURE); pc_->DestroyDataChannelTransport(error); } } void SdpOfferAnswerHandler::UpdateEndedRemoteMediaStreams() { RTC_DCHECK_RUN_ON(signaling_thread()); std::vector> streams_to_remove; for (size_t i = 0; i < remote_streams_->count(); ++i) { MediaStreamInterface* stream = remote_streams_->at(i); if (stream->GetAudioTracks().empty() && stream->GetVideoTracks().empty()) { streams_to_remove.push_back( rtc::scoped_refptr(stream)); } } for (auto& stream : streams_to_remove) { remote_streams_->RemoveStream(stream.get()); pc_->Observer()->OnRemoveStream(std::move(stream)); } } bool SdpOfferAnswerHandler::UseCandidatesInRemoteDescription() { RTC_DCHECK_RUN_ON(signaling_thread()); auto* remote_desc = remote_description(); if (!remote_desc) { return true; } bool ret = true; for (size_t m = 0; m < remote_desc->number_of_mediasections(); ++m) { const IceCandidateCollection* candidates = remote_desc->candidates(m); for (size_t n = 0; n < candidates->count(); ++n) { const IceCandidateInterface* candidate = candidates->at(n); bool valid = false; if (!ReadyToUseRemoteCandidate(candidate, remote_desc, &valid)) { if (valid) { RTC_LOG(LS_INFO) << "UseCandidatesInRemoteDescription: Not ready to use " "candidate."; } continue; } ret = UseCandidate(candidate); if (!ret) { break; } } } return ret; } bool SdpOfferAnswerHandler::UseCandidate( const IceCandidateInterface* candidate) { RTC_DCHECK_RUN_ON(signaling_thread()); rtc::Thread::ScopedDisallowBlockingCalls no_blocking_calls; RTCErrorOr result = FindContentInfo(remote_description(), candidate); if (!result.ok()) return false; const cricket::Candidate& c = candidate->candidate(); RTCError error = cricket::VerifyCandidate(c); if (!error.ok()) { RTC_LOG(LS_WARNING) << "Invalid candidate: " << c.ToString(); return true; } pc_->AddRemoteCandidate(result.value()->name, c); return true; } // 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 SessionDescriptionInterface* current_remote_desc = remote_desc ? remote_desc : remote_description(); if (!current_remote_desc) { return false; } RTCErrorOr result = FindContentInfo(current_remote_desc, candidate); if (!result.ok()) { RTC_LOG(LS_ERROR) << "ReadyToUseRemoteCandidate: Invalid candidate. " << result.error().message(); *valid = false; return false; } return true; } RTCErrorOr SdpOfferAnswerHandler::FindContentInfo( const SessionDescriptionInterface* description, const IceCandidateInterface* candidate) { if (!candidate->sdp_mid().empty()) { auto& contents = description->description()->contents(); auto it = absl::c_find_if( contents, [candidate](const cricket::ContentInfo& content_info) { return content_info.mid() == candidate->sdp_mid(); }); if (it == contents.end()) { LOG_AND_RETURN_ERROR( RTCErrorType::INVALID_PARAMETER, "Mid " + candidate->sdp_mid() + " specified but no media section with that mid found."); } else { return &*it; } } else if (candidate->sdp_mline_index() >= 0) { size_t mediacontent_index = static_cast(candidate->sdp_mline_index()); size_t content_size = description->description()->contents().size(); if (mediacontent_index < content_size) { return &description->description()->contents()[mediacontent_index]; } else { LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_RANGE, "Media line index (" + rtc::ToString(candidate->sdp_mline_index()) + ") out of range (number of mlines: " + rtc::ToString(content_size) + ")."); } } LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, "Neither sdp_mline_index nor sdp_mid specified."); } RTCError SdpOfferAnswerHandler::CreateChannels(const SessionDescription& desc) { TRACE_EVENT0("webrtc", "SdpOfferAnswerHandler::CreateChannels"); // Creating the media channels. Transports should already have been created // at this point. RTC_DCHECK_RUN_ON(signaling_thread()); const cricket::ContentInfo* voice = cricket::GetFirstAudioContent(&desc); if (voice && !voice->rejected && !rtp_manager()->GetAudioTransceiver()->internal()->channel()) { auto error = rtp_manager()->GetAudioTransceiver()->internal()->CreateChannel( voice->name, pc_->call_ptr(), pc_->configuration()->media_config, pc_->SrtpRequired(), pc_->GetCryptoOptions(), audio_options(), video_options(), video_bitrate_allocator_factory_.get(), [&](absl::string_view mid) { RTC_DCHECK_RUN_ON(network_thread()); return transport_controller_n()->GetRtpTransport(mid); }); if (!error.ok()) { return error; } } const cricket::ContentInfo* video = cricket::GetFirstVideoContent(&desc); if (video && !video->rejected && !rtp_manager()->GetVideoTransceiver()->internal()->channel()) { auto error = rtp_manager()->GetVideoTransceiver()->internal()->CreateChannel( video->name, pc_->call_ptr(), pc_->configuration()->media_config, pc_->SrtpRequired(), pc_->GetCryptoOptions(), audio_options(), video_options(), video_bitrate_allocator_factory_.get(), [&](absl::string_view mid) { RTC_DCHECK_RUN_ON(network_thread()); return transport_controller_n()->GetRtpTransport(mid); }); if (!error.ok()) { return error; } } 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 (const auto& transceiver : list) { if (transceiver->media_type() == cricket::MEDIA_TYPE_VIDEO) { transceiver->internal()->ClearChannel(); } } for (const auto& 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, absl::optional* audio_index, absl::optional* video_index, absl::optional* 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(); } else if (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(); } else if (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; } cricket::MediaDescriptionOptions SdpOfferAnswerHandler::GetMediaDescriptionOptionsForRejectedData( const std::string& mid) const { RTC_DCHECK_RUN_ON(signaling_thread()); cricket::MediaDescriptionOptions options(cricket::MEDIA_TYPE_DATA, mid, RtpTransceiverDirection::kInactive, /*stopped=*/true); return options; } bool SdpOfferAnswerHandler::UpdatePayloadTypeDemuxingState( cricket::ContentSource source, const std::map& 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 audio_payload_types; std::set video_payload_types; bool pt_demuxing_possible_audio = true; bool pt_demuxing_possible_video = true; }; std::map 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); } else if (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); } else if (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> channels_to_update; for (const auto& transceiver : transceivers()->ListInternal()) { cricket::ChannelInterface* channel = transceiver->channel(); const ContentInfo* content = FindMediaSectionForTransceiver(transceiver, sdesc); if (!channel || !content) { continue; } const cricket::MediaType media_type = channel->media_type(); if (media_type != cricket::MediaType::MEDIA_TYPE_AUDIO && media_type != cricket::MediaType::MEDIA_TYPE_VIDEO) { continue; } RtpTransceiverDirection local_direction = content->media_description()->direction(); if (source == cricket::CS_REMOTE) { local_direction = RtpTransceiverDirectionReversed(local_direction); } auto bundle_it = bundle_groups_by_mid.find(channel->mid()); const cricket::ContentGroup* bundle_group = bundle_it != bundle_groups_by_mid.end() ? bundle_it->second : nullptr; bool pt_demux_enabled = RtpTransceiverDirectionHasRecv(local_direction); if (media_type == cricket::MediaType::MEDIA_TYPE_AUDIO) { pt_demux_enabled &= !bundle_group || (bundled_pt_demux_allowed_audio && payload_types_by_bundle[bundle_group].pt_demuxing_possible_audio); if (pt_demux_enabled) { pt_demuxing_has_been_used_audio_ = true; } } else { RTC_DCHECK_EQ(media_type, cricket::MediaType::MEDIA_TYPE_VIDEO); pt_demux_enabled &= !bundle_group || (bundled_pt_demux_allowed_video && payload_types_by_bundle[bundle_group].pt_demuxing_possible_video); if (pt_demux_enabled) { pt_demuxing_has_been_used_video_ = true; } } channels_to_update.emplace_back(pt_demux_enabled, transceiver->channel()); } if (channels_to_update.empty()) { return true; } // 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 (const auto& 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? return false; } } return true; }); } bool SdpOfferAnswerHandler::ConfiguredForMedia() const { return context_->media_engine(); } } // namespace webrtc