diff options
Diffstat (limited to 'pc/media_session.cc')
| -rw-r--r-- | pc/media_session.cc | 367 |
1 files changed, 195 insertions, 172 deletions
diff --git a/pc/media_session.cc b/pc/media_session.cc index 2e779bd7b1..3c73ddf535 100644 --- a/pc/media_session.cc +++ b/pc/media_session.cc @@ -989,68 +989,6 @@ static Codecs MatchCodecPreference( return filtered_codecs; } -static bool FindByUriAndEncryption(const RtpHeaderExtensions& extensions, - const webrtc::RtpExtension& ext_to_match, - webrtc::RtpExtension* found_extension) { - auto it = absl::c_find_if( - extensions, [&ext_to_match](const webrtc::RtpExtension& extension) { - // We assume that all URIs are given in a canonical - // format. - return extension.uri == ext_to_match.uri && - extension.encrypt == ext_to_match.encrypt; - }); - if (it == extensions.end()) { - return false; - } - if (found_extension) { - *found_extension = *it; - } - return true; -} - -static bool FindByUri(const RtpHeaderExtensions& extensions, - const webrtc::RtpExtension& ext_to_match, - webrtc::RtpExtension* found_extension) { - // We assume that all URIs are given in a canonical format. - const webrtc::RtpExtension* found = - webrtc::RtpExtension::FindHeaderExtensionByUri(extensions, - ext_to_match.uri); - if (!found) { - return false; - } - if (found_extension) { - *found_extension = *found; - } - return true; -} - -static bool FindByUriWithEncryptionPreference( - const RtpHeaderExtensions& extensions, - absl::string_view uri_to_match, - bool encryption_preference, - webrtc::RtpExtension* found_extension) { - const webrtc::RtpExtension* unencrypted_extension = nullptr; - for (const webrtc::RtpExtension& extension : extensions) { - // We assume that all URIs are given in a canonical format. - if (extension.uri == uri_to_match) { - if (!encryption_preference || extension.encrypt) { - if (found_extension) { - *found_extension = extension; - } - return true; - } - unencrypted_extension = &extension; - } - } - if (unencrypted_extension) { - if (found_extension) { - *found_extension = *unencrypted_extension; - } - return true; - } - return false; -} - // Adds all extensions from |reference_extensions| to |offered_extensions| that // don't already exist in |offered_extensions| and ensure the IDs don't // collide. If an extension is added, it's also added to |regular_extensions| or @@ -1065,22 +1003,28 @@ static void MergeRtpHdrExts(const RtpHeaderExtensions& reference_extensions, RtpHeaderExtensions* encrypted_extensions, UsedRtpHeaderExtensionIds* used_ids) { for (auto reference_extension : reference_extensions) { - if (!FindByUriAndEncryption(*offered_extensions, reference_extension, - nullptr)) { - webrtc::RtpExtension existing; + if (!webrtc::RtpExtension::FindHeaderExtensionByUriAndEncryption( + *offered_extensions, reference_extension.uri, + reference_extension.encrypt)) { if (reference_extension.encrypt) { - if (FindByUriAndEncryption(*encrypted_extensions, reference_extension, - &existing)) { - offered_extensions->push_back(existing); + const webrtc::RtpExtension* existing = + webrtc::RtpExtension::FindHeaderExtensionByUriAndEncryption( + *encrypted_extensions, reference_extension.uri, + reference_extension.encrypt); + if (existing) { + offered_extensions->push_back(*existing); } else { used_ids->FindAndSetIdUsed(&reference_extension); encrypted_extensions->push_back(reference_extension); offered_extensions->push_back(reference_extension); } } else { - if (FindByUriAndEncryption(*regular_extensions, reference_extension, - &existing)) { - offered_extensions->push_back(existing); + const webrtc::RtpExtension* existing = + webrtc::RtpExtension::FindHeaderExtensionByUriAndEncryption( + *regular_extensions, reference_extension.uri, + reference_extension.encrypt); + if (existing) { + offered_extensions->push_back(*existing); } else { used_ids->FindAndSetIdUsed(&reference_extension); regular_extensions->push_back(reference_extension); @@ -1091,41 +1035,86 @@ static void MergeRtpHdrExts(const RtpHeaderExtensions& reference_extensions, } } -static void AddEncryptedVersionsOfHdrExts(RtpHeaderExtensions* extensions, - RtpHeaderExtensions* all_extensions, - UsedRtpHeaderExtensionIds* used_ids) { - RtpHeaderExtensions encrypted_extensions; - for (const webrtc::RtpExtension& extension : *extensions) { - webrtc::RtpExtension existing; - // Don't add encrypted extensions again that were already included in a - // previous offer or regular extensions that are also included as encrypted - // extensions. - if (extension.encrypt || - !webrtc::RtpExtension::IsEncryptionSupported(extension.uri) || - (FindByUriWithEncryptionPreference(*extensions, extension.uri, true, - &existing) && - existing.encrypt)) { +static void AddEncryptedVersionsOfHdrExts( + RtpHeaderExtensions* offered_extensions, + RtpHeaderExtensions* encrypted_extensions, + UsedRtpHeaderExtensionIds* used_ids) { + RtpHeaderExtensions encrypted_extensions_to_add; + for (const auto& extension : *offered_extensions) { + // Skip existing encrypted offered extension + if (extension.encrypt) { continue; } - if (FindByUri(*all_extensions, extension, &existing)) { - encrypted_extensions.push_back(existing); - } else { - webrtc::RtpExtension encrypted(extension); - encrypted.encrypt = true; - used_ids->FindAndSetIdUsed(&encrypted); - all_extensions->push_back(encrypted); - encrypted_extensions.push_back(encrypted); + // Skip if we cannot encrypt the extension + if (!webrtc::RtpExtension::IsEncryptionSupported(extension.uri)) { + continue; } + + // Skip if an encrypted extension with that URI already exists in the + // offered extensions. + const bool have_encrypted_extension = + webrtc::RtpExtension::FindHeaderExtensionByUriAndEncryption( + *offered_extensions, extension.uri, true); + if (have_encrypted_extension) { + continue; + } + + // Determine if a shared encrypted extension with that URI already exists. + const webrtc::RtpExtension* shared_encrypted_extension = + webrtc::RtpExtension::FindHeaderExtensionByUriAndEncryption( + *encrypted_extensions, extension.uri, true); + if (shared_encrypted_extension) { + // Re-use the shared encrypted extension + encrypted_extensions_to_add.push_back(*shared_encrypted_extension); + continue; + } + + // None exists. Create a new shared encrypted extension from the + // non-encrypted one. + webrtc::RtpExtension new_encrypted_extension(extension); + new_encrypted_extension.encrypt = true; + used_ids->FindAndSetIdUsed(&new_encrypted_extension); + encrypted_extensions->push_back(new_encrypted_extension); + encrypted_extensions_to_add.push_back(new_encrypted_extension); } - extensions->insert(extensions->end(), encrypted_extensions.begin(), - encrypted_extensions.end()); + + // Append the additional encrypted extensions to be offered + offered_extensions->insert(offered_extensions->end(), + encrypted_extensions_to_add.begin(), + encrypted_extensions_to_add.end()); +} + +// Mostly identical to RtpExtension::FindHeaderExtensionByUri but discards any +// encrypted extensions that this implementation cannot encrypt. +static const webrtc::RtpExtension* FindHeaderExtensionByUriDiscardUnsupported( + const std::vector<webrtc::RtpExtension>& extensions, + absl::string_view uri, + webrtc::RtpExtension::Filter filter) { + // Note: While it's technically possible to decrypt extensions that we don't + // encrypt, the symmetric API of libsrtp does not allow us to supply + // different IDs for encryption/decryption of header extensions depending on + // whether the packet is inbound or outbound. Thereby, we are limited to + // what we can send in encrypted form. + if (!webrtc::RtpExtension::IsEncryptionSupported(uri)) { + // If there's no encryption support and we only want encrypted extensions, + // there's no point in continuing the search here. + if (filter == webrtc::RtpExtension::kRequireEncryptedExtension) { + return nullptr; + } + + // Instruct to only return non-encrypted extensions + filter = webrtc::RtpExtension::Filter::kDiscardEncryptedExtension; + } + + return webrtc::RtpExtension::FindHeaderExtensionByUri(extensions, uri, + filter); } static void NegotiateRtpHeaderExtensions( const RtpHeaderExtensions& local_extensions, const RtpHeaderExtensions& offered_extensions, - bool enable_encrypted_rtp_header_extensions, + webrtc::RtpExtension::Filter filter, RtpHeaderExtensions* negotiated_extensions) { // TransportSequenceNumberV2 is not offered by default. The special logic for // the TransportSequenceNumber extensions works as follows: @@ -1134,9 +1123,9 @@ static void NegotiateRtpHeaderExtensions( // V1 and V2 V2 regardless of local_extensions. // V2 V2 regardless of local_extensions. const webrtc::RtpExtension* transport_sequence_number_v2_offer = - webrtc::RtpExtension::FindHeaderExtensionByUri( + FindHeaderExtensionByUriDiscardUnsupported( offered_extensions, - webrtc::RtpExtension::kTransportSequenceNumberV2Uri); + webrtc::RtpExtension::kTransportSequenceNumberV2Uri, filter); bool frame_descriptor_in_local = false; bool dependency_descriptor_in_local = false; @@ -1149,10 +1138,10 @@ static void NegotiateRtpHeaderExtensions( dependency_descriptor_in_local = true; else if (ours.uri == webrtc::RtpExtension::kAbsoluteCaptureTimeUri) abs_capture_time_in_local = true; - webrtc::RtpExtension theirs; - if (FindByUriWithEncryptionPreference( - offered_extensions, ours.uri, - enable_encrypted_rtp_header_extensions, &theirs)) { + const webrtc::RtpExtension* theirs = + FindHeaderExtensionByUriDiscardUnsupported(offered_extensions, ours.uri, + filter); + if (theirs) { if (transport_sequence_number_v2_offer && ours.uri == webrtc::RtpExtension::kTransportSequenceNumberUri) { // Don't respond to @@ -1162,7 +1151,7 @@ static void NegotiateRtpHeaderExtensions( continue; } else { // We respond with their RTP header extension id. - negotiated_extensions->push_back(theirs); + negotiated_extensions->push_back(*theirs); } } } @@ -1174,28 +1163,35 @@ static void NegotiateRtpHeaderExtensions( // Frame descriptors support. If the extension is not present locally, but is // in the offer, we add it to the list. - webrtc::RtpExtension theirs; - if (!dependency_descriptor_in_local && - FindByUriWithEncryptionPreference( - offered_extensions, webrtc::RtpExtension::kDependencyDescriptorUri, - enable_encrypted_rtp_header_extensions, &theirs)) { - negotiated_extensions->push_back(theirs); - } - if (!frame_descriptor_in_local && - FindByUriWithEncryptionPreference( - offered_extensions, - webrtc::RtpExtension::kGenericFrameDescriptorUri00, - enable_encrypted_rtp_header_extensions, &theirs)) { - negotiated_extensions->push_back(theirs); + if (!dependency_descriptor_in_local) { + const webrtc::RtpExtension* theirs = + FindHeaderExtensionByUriDiscardUnsupported( + offered_extensions, webrtc::RtpExtension::kDependencyDescriptorUri, + filter); + if (theirs) { + negotiated_extensions->push_back(*theirs); + } + } + if (!frame_descriptor_in_local) { + const webrtc::RtpExtension* theirs = + FindHeaderExtensionByUriDiscardUnsupported( + offered_extensions, + webrtc::RtpExtension::kGenericFrameDescriptorUri00, filter); + if (theirs) { + negotiated_extensions->push_back(*theirs); + } } // Absolute capture time support. If the extension is not present locally, but // is in the offer, we add it to the list. - if (!abs_capture_time_in_local && - FindByUriWithEncryptionPreference( - offered_extensions, webrtc::RtpExtension::kAbsoluteCaptureTimeUri, - enable_encrypted_rtp_header_extensions, &theirs)) { - negotiated_extensions->push_back(theirs); + if (!abs_capture_time_in_local) { + const webrtc::RtpExtension* theirs = + FindHeaderExtensionByUriDiscardUnsupported( + offered_extensions, webrtc::RtpExtension::kAbsoluteCaptureTimeUri, + filter); + if (theirs) { + negotiated_extensions->push_back(*theirs); + } } } @@ -1250,10 +1246,14 @@ static bool CreateMediaContentAnswer( bool bundle_enabled, MediaContentDescription* answer) { answer->set_extmap_allow_mixed_enum(offer->extmap_allow_mixed_enum()); + const webrtc::RtpExtension::Filter extensions_filter = + enable_encrypted_rtp_header_extensions + ? webrtc::RtpExtension::Filter::kPreferEncryptedExtension + : webrtc::RtpExtension::Filter::kDiscardEncryptedExtension; RtpHeaderExtensions negotiated_rtp_extensions; - NegotiateRtpHeaderExtensions( - local_rtp_extensions, offer->rtp_header_extensions(), - enable_encrypted_rtp_header_extensions, &negotiated_rtp_extensions); + NegotiateRtpHeaderExtensions(local_rtp_extensions, + offer->rtp_header_extensions(), + extensions_filter, &negotiated_rtp_extensions); answer->set_rtp_header_extensions(negotiated_rtp_extensions); answer->set_rtcp_mux(session_options.rtcp_mux_enabled && offer->rtcp_mux()); @@ -1515,10 +1515,6 @@ std::unique_ptr<SessionDescription> MediaSessionDescriptionFactory::CreateOffer( VideoCodecs offer_video_codecs; GetCodecsForOffer(current_active_contents, &offer_audio_codecs, &offer_video_codecs); - if (!session_options.vad_enabled) { - // If application doesn't want CN codecs in offer. - StripCNCodecs(&offer_audio_codecs); - } AudioVideoRtpHeaderExtensions extensions_with_ids = GetOfferedRtpHeaderExtensionsWithIds( current_active_contents, session_options.offer_extmap_allow_mixed, @@ -1664,19 +1660,23 @@ MediaSessionDescriptionFactory::CreateAnswer( GetCodecsForAnswer(current_active_contents, *offer, &answer_audio_codecs, &answer_video_codecs); - if (!session_options.vad_enabled) { - // If application doesn't want CN codecs in answer. - StripCNCodecs(&answer_audio_codecs); - } - auto answer = std::make_unique<SessionDescription>(); // If the offer supports BUNDLE, and we want to use it too, create a BUNDLE // group in the answer with the appropriate content names. - const ContentGroup* offer_bundle = offer->GetGroupByName(GROUP_TYPE_BUNDLE); - ContentGroup answer_bundle(GROUP_TYPE_BUNDLE); - // Transport info shared by the bundle group. - std::unique_ptr<TransportInfo> bundle_transport; + std::vector<const ContentGroup*> offer_bundles = + offer->GetGroupsByName(GROUP_TYPE_BUNDLE); + // There are as many answer BUNDLE groups as offer BUNDLE groups (even if + // rejected, we respond with an empty group). |offer_bundles|, + // |answer_bundles| and |bundle_transports| share the same size and indices. + std::vector<ContentGroup> answer_bundles; + std::vector<std::unique_ptr<TransportInfo>> bundle_transports; + answer_bundles.reserve(offer_bundles.size()); + bundle_transports.reserve(offer_bundles.size()); + for (size_t i = 0; i < offer_bundles.size(); ++i) { + answer_bundles.emplace_back(GROUP_TYPE_BUNDLE); + bundle_transports.emplace_back(nullptr); + } answer->set_extmap_allow_mixed(offer->extmap_allow_mixed()); @@ -1691,6 +1691,18 @@ MediaSessionDescriptionFactory::CreateAnswer( RTC_DCHECK( IsMediaContentOfType(offer_content, media_description_options.type)); RTC_DCHECK(media_description_options.mid == offer_content->name); + // Get the index of the BUNDLE group that this MID belongs to, if any. + absl::optional<size_t> bundle_index; + for (size_t i = 0; i < offer_bundles.size(); ++i) { + if (offer_bundles[i]->HasContentName(media_description_options.mid)) { + bundle_index = i; + break; + } + } + TransportInfo* bundle_transport = + bundle_index.has_value() ? bundle_transports[bundle_index.value()].get() + : nullptr; + const ContentInfo* current_content = nullptr; if (current_description && msection_index < current_description->contents().size()) { @@ -1703,35 +1715,34 @@ MediaSessionDescriptionFactory::CreateAnswer( case MEDIA_TYPE_AUDIO: if (!AddAudioContentForAnswer( media_description_options, session_options, offer_content, - offer, current_content, current_description, - bundle_transport.get(), answer_audio_codecs, header_extensions, - ¤t_streams, answer.get(), &ice_credentials)) { + offer, current_content, current_description, bundle_transport, + answer_audio_codecs, header_extensions, ¤t_streams, + answer.get(), &ice_credentials)) { return nullptr; } break; case MEDIA_TYPE_VIDEO: if (!AddVideoContentForAnswer( media_description_options, session_options, offer_content, - offer, current_content, current_description, - bundle_transport.get(), answer_video_codecs, header_extensions, - ¤t_streams, answer.get(), &ice_credentials)) { + offer, current_content, current_description, bundle_transport, + answer_video_codecs, header_extensions, ¤t_streams, + answer.get(), &ice_credentials)) { return nullptr; } break; case MEDIA_TYPE_DATA: - if (!AddDataContentForAnswer(media_description_options, session_options, - offer_content, offer, current_content, - current_description, - bundle_transport.get(), ¤t_streams, - answer.get(), &ice_credentials)) { + if (!AddDataContentForAnswer( + media_description_options, session_options, offer_content, + offer, current_content, current_description, bundle_transport, + ¤t_streams, answer.get(), &ice_credentials)) { return nullptr; } break; case MEDIA_TYPE_UNSUPPORTED: if (!AddUnsupportedContentForAnswer( media_description_options, session_options, offer_content, - offer, current_content, current_description, - bundle_transport.get(), answer.get(), &ice_credentials)) { + offer, current_content, current_description, bundle_transport, + answer.get(), &ice_credentials)) { return nullptr; } break; @@ -1742,37 +1753,41 @@ MediaSessionDescriptionFactory::CreateAnswer( // See if we can add the newly generated m= section to the BUNDLE group in // the answer. ContentInfo& added = answer->contents().back(); - if (!added.rejected && session_options.bundle_enabled && offer_bundle && - offer_bundle->HasContentName(added.name)) { - answer_bundle.AddContentName(added.name); - bundle_transport.reset( + if (!added.rejected && session_options.bundle_enabled && + bundle_index.has_value()) { + // The |bundle_index| is for |media_description_options.mid|. + RTC_DCHECK_EQ(media_description_options.mid, added.name); + answer_bundles[bundle_index.value()].AddContentName(added.name); + bundle_transports[bundle_index.value()].reset( new TransportInfo(*answer->GetTransportInfoByName(added.name))); } } - // If a BUNDLE group was offered, put a BUNDLE group in the answer even if - // it's empty. RFC5888 says: + // If BUNDLE group(s) were offered, put the same number of BUNDLE groups in + // the answer even if they're empty. RFC5888 says: // // A SIP entity that receives an offer that contains an "a=group" line // with semantics that are understood MUST return an answer that // contains an "a=group" line with the same semantics. - if (offer_bundle) { - answer->AddGroup(answer_bundle); - } - - if (answer_bundle.FirstContentName()) { - // Share the same ICE credentials and crypto params across all contents, - // as BUNDLE requires. - if (!UpdateTransportInfoForBundle(answer_bundle, answer.get())) { - RTC_LOG(LS_ERROR) - << "CreateAnswer failed to UpdateTransportInfoForBundle."; - return NULL; - } + if (!offer_bundles.empty()) { + for (const ContentGroup& answer_bundle : answer_bundles) { + answer->AddGroup(answer_bundle); + + if (answer_bundle.FirstContentName()) { + // Share the same ICE credentials and crypto params across all contents, + // as BUNDLE requires. + if (!UpdateTransportInfoForBundle(answer_bundle, answer.get())) { + RTC_LOG(LS_ERROR) + << "CreateAnswer failed to UpdateTransportInfoForBundle."; + return NULL; + } - if (!UpdateCryptoParamsForBundle(answer_bundle, answer.get())) { - RTC_LOG(LS_ERROR) - << "CreateAnswer failed to UpdateCryptoParamsForBundle."; - return NULL; + if (!UpdateCryptoParamsForBundle(answer_bundle, answer.get())) { + RTC_LOG(LS_ERROR) + << "CreateAnswer failed to UpdateCryptoParamsForBundle."; + return NULL; + } + } } } @@ -2159,6 +2174,10 @@ bool MediaSessionDescriptionFactory::AddAudioContentForOffer( } } } + if (!session_options.vad_enabled) { + // If application doesn't want CN codecs in offer. + StripCNCodecs(&filtered_codecs); + } cricket::SecurePolicy sdes_policy = IsDtlsActive(current_content, current_description) ? cricket::SEC_DISABLED @@ -2434,6 +2453,10 @@ bool MediaSessionDescriptionFactory::AddAudioContentForAnswer( } } } + if (!session_options.vad_enabled) { + // If application doesn't want CN codecs in answer. + StripCNCodecs(&filtered_codecs); + } bool bundle_enabled = offer_description->HasGroup(GROUP_TYPE_BUNDLE) && session_options.bundle_enabled; |