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webrtc / src.git / e5c426561911602a2cd8c763a4f7a04c4cde2c97 / . / pc / mediasession.cc
blob: 835f76d1cf0cb8764394a29236b84de3657f377b [file] [log] [blame]
/*
* Copyright 2004 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "pc/mediasession.h"
#include <algorithm> // For std::find_if, std::sort.
#include <functional>
#include <map>
#include <memory>
#include <set>
#include <unordered_map>
#include <utility>
#include "api/optional.h"
#include "common_types.h" // NOLINT(build/include)
#include "media/base/cryptoparams.h"
#include "media/base/h264_profile_level_id.h"
#include "media/base/mediaconstants.h"
#include "p2p/base/p2pconstants.h"
#include "pc/channelmanager.h"
#include "pc/srtpfilter.h"
#include "rtc_base/base64.h"
#include "rtc_base/checks.h"
#include "rtc_base/helpers.h"
#include "rtc_base/logging.h"
#include "rtc_base/stringutils.h"
namespace {
const char kInline[] = "inline:";
void GetSupportedSdesCryptoSuiteNames(void (*func)(const rtc::CryptoOptions&,
std::vector<int>*),
const rtc::CryptoOptions& crypto_options,
std::vector<std::string>* names) {
std::vector<int> crypto_suites;
func(crypto_options, &crypto_suites);
for (const auto crypto : crypto_suites) {
names->push_back(rtc::SrtpCryptoSuiteToName(crypto));
}
}
} // namespace
namespace cricket {
// RTP Profile names
// http://www.iana.org/assignments/rtp-parameters/rtp-parameters.xml
// RFC4585
const char kMediaProtocolAvpf[] = "RTP/AVPF";
// RFC5124
const char kMediaProtocolDtlsSavpf[] = "UDP/TLS/RTP/SAVPF";
// We always generate offers with "UDP/TLS/RTP/SAVPF" when using DTLS-SRTP,
// but we tolerate "RTP/SAVPF" in offers we receive, for compatibility.
const char kMediaProtocolSavpf[] = "RTP/SAVPF";
const char kMediaProtocolRtpPrefix[] = "RTP/";
const char kMediaProtocolSctp[] = "SCTP";
const char kMediaProtocolDtlsSctp[] = "DTLS/SCTP";
const char kMediaProtocolUdpDtlsSctp[] = "UDP/DTLS/SCTP";
const char kMediaProtocolTcpDtlsSctp[] = "TCP/DTLS/SCTP";
// Note that the below functions support some protocol strings purely for
// legacy compatibility, as required by JSEP in Section 5.1.2, Profile Names
// and Interoperability.
static bool IsDtlsRtp(const std::string& protocol) {
// Most-likely values first.
return protocol == "UDP/TLS/RTP/SAVPF" || protocol == "TCP/TLS/RTP/SAVPF" ||
protocol == "UDP/TLS/RTP/SAVP" || protocol == "TCP/TLS/RTP/SAVP";
}
static bool IsPlainRtp(const std::string& protocol) {
// Most-likely values first.
return protocol == "RTP/SAVPF" || protocol == "RTP/AVPF" ||
protocol == "RTP/SAVP" || protocol == "RTP/AVP";
}
static bool IsDtlsSctp(const std::string& protocol) {
return protocol == kMediaProtocolDtlsSctp ||
protocol == kMediaProtocolUdpDtlsSctp ||
protocol == kMediaProtocolTcpDtlsSctp;
}
static bool IsPlainSctp(const std::string& protocol) {
return protocol == kMediaProtocolSctp;
}
static bool IsSctp(const std::string& protocol) {
return IsPlainSctp(protocol) || IsDtlsSctp(protocol);
}
RtpTransceiverDirection RtpTransceiverDirection::FromMediaContentDirection(
MediaContentDirection md) {
const bool send = (md == MD_SENDRECV || md == MD_SENDONLY);
const bool recv = (md == MD_SENDRECV || md == MD_RECVONLY);
return RtpTransceiverDirection(send, recv);
}
MediaContentDirection RtpTransceiverDirection::ToMediaContentDirection() const {
if (send && recv) {
return MD_SENDRECV;
} else if (send) {
return MD_SENDONLY;
} else if (recv) {
return MD_RECVONLY;
}
return MD_INACTIVE;
}
RtpTransceiverDirection
NegotiateRtpTransceiverDirection(RtpTransceiverDirection offer,
RtpTransceiverDirection wants) {
return RtpTransceiverDirection(offer.recv && wants.send,
offer.send && wants.recv);
}
static bool IsMediaContentOfType(const ContentInfo* content,
MediaType media_type) {
if (!IsMediaContent(content)) {
return false;
}
const MediaContentDescription* mdesc =
static_cast<const MediaContentDescription*>(content->description);
return mdesc && mdesc->type() == media_type;
}
static bool CreateCryptoParams(int tag, const std::string& cipher,
CryptoParams *out) {
int key_len;
int salt_len;
if (!rtc::GetSrtpKeyAndSaltLengths(
rtc::SrtpCryptoSuiteFromName(cipher), &key_len, &salt_len)) {
return false;
}
int master_key_len = key_len + salt_len;
std::string master_key;
if (!rtc::CreateRandomData(master_key_len, &master_key)) {
return false;
}
RTC_CHECK_EQ(master_key_len, master_key.size());
std::string key = rtc::Base64::Encode(master_key);
out->tag = tag;
out->cipher_suite = cipher;
out->key_params = kInline;
out->key_params += key;
return true;
}
static bool AddCryptoParams(const std::string& cipher_suite,
CryptoParamsVec *out) {
int size = static_cast<int>(out->size());
out->resize(size + 1);
return CreateCryptoParams(size, cipher_suite, &out->at(size));
}
void AddMediaCryptos(const CryptoParamsVec& cryptos,
MediaContentDescription* media) {
for (CryptoParamsVec::const_iterator crypto = cryptos.begin();
crypto != cryptos.end(); ++crypto) {
media->AddCrypto(*crypto);
}
}
bool CreateMediaCryptos(const std::vector<std::string>& crypto_suites,
MediaContentDescription* media) {
CryptoParamsVec cryptos;
for (std::vector<std::string>::const_iterator it = crypto_suites.begin();
it != crypto_suites.end(); ++it) {
if (!AddCryptoParams(*it, &cryptos)) {
return false;
}
}
AddMediaCryptos(cryptos, media);
return true;
}
const CryptoParamsVec* GetCryptos(const ContentInfo* content) {
if (!content) {
return nullptr;
}
RTC_DCHECK(IsMediaContent(content));
return &(static_cast<const MediaContentDescription*>(content->description)
->cryptos());
}
bool FindMatchingCrypto(const CryptoParamsVec& cryptos,
const CryptoParams& crypto,
CryptoParams* out) {
for (CryptoParamsVec::const_iterator it = cryptos.begin();
it != cryptos.end(); ++it) {
if (crypto.Matches(*it)) {
*out = *it;
return true;
}
}
return false;
}
// For audio, HMAC 32 is prefered over HMAC 80 because of the low overhead.
void GetSupportedAudioSdesCryptoSuites(const rtc::CryptoOptions& crypto_options,
std::vector<int>* crypto_suites) {
if (crypto_options.enable_gcm_crypto_suites) {
crypto_suites->push_back(rtc::SRTP_AEAD_AES_256_GCM);
crypto_suites->push_back(rtc::SRTP_AEAD_AES_128_GCM);
}
crypto_suites->push_back(rtc::SRTP_AES128_CM_SHA1_32);
crypto_suites->push_back(rtc::SRTP_AES128_CM_SHA1_80);
}
void GetSupportedAudioSdesCryptoSuiteNames(
const rtc::CryptoOptions& crypto_options,
std::vector<std::string>* crypto_suite_names) {
GetSupportedSdesCryptoSuiteNames(GetSupportedAudioSdesCryptoSuites,
crypto_options, crypto_suite_names);
}
void GetSupportedVideoSdesCryptoSuites(const rtc::CryptoOptions& crypto_options,
std::vector<int>* crypto_suites) {
if (crypto_options.enable_gcm_crypto_suites) {
crypto_suites->push_back(rtc::SRTP_AEAD_AES_256_GCM);
crypto_suites->push_back(rtc::SRTP_AEAD_AES_128_GCM);
}
crypto_suites->push_back(rtc::SRTP_AES128_CM_SHA1_80);
}
void GetSupportedVideoSdesCryptoSuiteNames(
const rtc::CryptoOptions& crypto_options,
std::vector<std::string>* crypto_suite_names) {
GetSupportedSdesCryptoSuiteNames(GetSupportedVideoSdesCryptoSuites,
crypto_options, crypto_suite_names);
}
void GetSupportedDataSdesCryptoSuites(const rtc::CryptoOptions& crypto_options,
std::vector<int>* crypto_suites) {
if (crypto_options.enable_gcm_crypto_suites) {
crypto_suites->push_back(rtc::SRTP_AEAD_AES_256_GCM);
crypto_suites->push_back(rtc::SRTP_AEAD_AES_128_GCM);
}
crypto_suites->push_back(rtc::SRTP_AES128_CM_SHA1_80);
}
void GetSupportedDataSdesCryptoSuiteNames(
const rtc::CryptoOptions& crypto_options,
std::vector<std::string>* crypto_suite_names) {
GetSupportedSdesCryptoSuiteNames(GetSupportedDataSdesCryptoSuites,
crypto_options, crypto_suite_names);
}
// Support any GCM cipher (if enabled through options). For video support only
// 80-bit SHA1 HMAC. For audio 32-bit HMAC is tolerated unless bundle is enabled
// because it is low overhead.
// Pick the crypto in the list that is supported.
static bool SelectCrypto(const MediaContentDescription* offer,
bool bundle,
const rtc::CryptoOptions& crypto_options,
CryptoParams *crypto) {
bool audio = offer->type() == MEDIA_TYPE_AUDIO;
const CryptoParamsVec& cryptos = offer->cryptos();
for (CryptoParamsVec::const_iterator i = cryptos.begin();
i != cryptos.end(); ++i) {
if ((crypto_options.enable_gcm_crypto_suites &&
rtc::IsGcmCryptoSuiteName(i->cipher_suite)) ||
rtc::CS_AES_CM_128_HMAC_SHA1_80 == i->cipher_suite ||
(rtc::CS_AES_CM_128_HMAC_SHA1_32 == i->cipher_suite && audio &&
!bundle)) {
return CreateCryptoParams(i->tag, i->cipher_suite, crypto);
}
}
return false;
}
// Generate random SSRC values that are not already present in |params_vec|.
// The generated values are added to |ssrcs|.
// |num_ssrcs| is the number of the SSRC will be generated.
static void GenerateSsrcs(const StreamParamsVec& params_vec,
int num_ssrcs,
std::vector<uint32_t>* ssrcs) {
for (int i = 0; i < num_ssrcs; i++) {
uint32_t candidate;
do {
candidate = rtc::CreateRandomNonZeroId();
} while (GetStreamBySsrc(params_vec, candidate) ||
std::count(ssrcs->begin(), ssrcs->end(), candidate) > 0);
ssrcs->push_back(candidate);
}
}
// Finds all StreamParams of all media types and attach them to stream_params.
static void GetCurrentStreamParams(const SessionDescription* sdesc,
StreamParamsVec* stream_params) {
if (!sdesc)
return;
const ContentInfos& contents = sdesc->contents();
for (ContentInfos::const_iterator content = contents.begin();
content != contents.end(); ++content) {
if (!IsMediaContent(&*content)) {
continue;
}
const MediaContentDescription* media =
static_cast<const MediaContentDescription*>(
content->description);
const StreamParamsVec& streams = media->streams();
for (StreamParamsVec::const_iterator it = streams.begin();
it != streams.end(); ++it) {
stream_params->push_back(*it);
}
}
}
// Filters the data codecs for the data channel type.
void FilterDataCodecs(std::vector<DataCodec>* codecs, bool sctp) {
// Filter RTP codec for SCTP and vice versa.
const char* codec_name =
sctp ? kGoogleRtpDataCodecName : kGoogleSctpDataCodecName;
for (std::vector<DataCodec>::iterator iter = codecs->begin();
iter != codecs->end();) {
if (CodecNamesEq(iter->name, codec_name)) {
iter = codecs->erase(iter);
} else {
++iter;
}
}
}
template <typename IdStruct>
class UsedIds {
public:
UsedIds(int min_allowed_id, int max_allowed_id)
: min_allowed_id_(min_allowed_id),
max_allowed_id_(max_allowed_id),
next_id_(max_allowed_id) {
}
// Loops through all Id in |ids| and changes its id if it is
// already in use by another IdStruct. Call this methods with all Id
// in a session description to make sure no duplicate ids exists.
// Note that typename Id must be a type of IdStruct.
template <typename Id>
void FindAndSetIdUsed(std::vector<Id>* ids) {
for (typename std::vector<Id>::iterator it = ids->begin();
it != ids->end(); ++it) {
FindAndSetIdUsed(&*it);
}
}
// Finds and sets an unused id if the |idstruct| id is already in use.
void FindAndSetIdUsed(IdStruct* idstruct) {
const int original_id = idstruct->id;
int new_id = idstruct->id;
if (original_id > max_allowed_id_ || original_id < min_allowed_id_) {
// If the original id is not in range - this is an id that can't be
// dynamically changed.
return;
}
if (IsIdUsed(original_id)) {
new_id = FindUnusedId();
LOG(LS_WARNING) << "Duplicate id found. Reassigning from " << original_id
<< " to " << new_id;
idstruct->id = new_id;
}
SetIdUsed(new_id);
}
private:
// Returns the first unused id in reverse order.
// This hopefully reduce the risk of more collisions. We want to change the
// default ids as little as possible.
int FindUnusedId() {
while (IsIdUsed(next_id_) && next_id_ >= min_allowed_id_) {
--next_id_;
}
RTC_DCHECK(next_id_ >= min_allowed_id_);
return next_id_;
}
bool IsIdUsed(int new_id) {
return id_set_.find(new_id) != id_set_.end();
}
void SetIdUsed(int new_id) {
id_set_.insert(new_id);
}
const int min_allowed_id_;
const int max_allowed_id_;
int next_id_;
std::set<int> id_set_;
};
// Helper class used for finding duplicate RTP payload types among audio, video
// and data codecs. When bundle is used the payload types may not collide.
class UsedPayloadTypes : public UsedIds<Codec> {
public:
UsedPayloadTypes()
: UsedIds<Codec>(kDynamicPayloadTypeMin, kDynamicPayloadTypeMax) {
}
private:
static const int kDynamicPayloadTypeMin = 96;
static const int kDynamicPayloadTypeMax = 127;
};
// Helper class used for finding duplicate RTP Header extension ids among
// audio and video extensions.
class UsedRtpHeaderExtensionIds : public UsedIds<webrtc::RtpExtension> {
public:
UsedRtpHeaderExtensionIds()
: UsedIds<webrtc::RtpExtension>(webrtc::RtpExtension::kMinId,
webrtc::RtpExtension::kMaxId) {}
private:
};
// Adds a StreamParams for each SenderOptions in |sender_options| to
// content_description.
// |current_params| - All currently known StreamParams of any media type.
template <class C>
static bool AddStreamParams(
const std::vector<SenderOptions>& sender_options,
const std::string& rtcp_cname,
StreamParamsVec* current_streams,
MediaContentDescriptionImpl<C>* content_description) {
// SCTP streams are not negotiated using SDP/ContentDescriptions.
if (IsSctp(content_description->protocol())) {
return true;
}
const bool include_rtx_streams =
ContainsRtxCodec(content_description->codecs());
const bool include_flexfec_stream =
ContainsFlexfecCodec(content_description->codecs());
for (const SenderOptions& sender : sender_options) {
// groupid is empty for StreamParams generated using
// MediaSessionDescriptionFactory.
StreamParams* param =
GetStreamByIds(*current_streams, "" /*group_id*/, sender.track_id);
if (!param) {
// This is a new sender.
std::vector<uint32_t> ssrcs;
GenerateSsrcs(*current_streams, sender.num_sim_layers, &ssrcs);
StreamParams stream_param;
stream_param.id = sender.track_id;
// Add the generated ssrc.
for (size_t i = 0; i < ssrcs.size(); ++i) {
stream_param.ssrcs.push_back(ssrcs[i]);
}
if (sender.num_sim_layers > 1) {
SsrcGroup group(kSimSsrcGroupSemantics, stream_param.ssrcs);
stream_param.ssrc_groups.push_back(group);
}
// Generate extra ssrcs for include_rtx_streams case.
if (include_rtx_streams) {
// Generate an RTX ssrc for every ssrc in the group.
std::vector<uint32_t> rtx_ssrcs;
GenerateSsrcs(*current_streams, static_cast<int>(ssrcs.size()),
&rtx_ssrcs);
for (size_t i = 0; i < ssrcs.size(); ++i) {
stream_param.AddFidSsrc(ssrcs[i], rtx_ssrcs[i]);
}
content_description->set_multistream(true);
}
// Generate extra ssrc for include_flexfec_stream case.
if (include_flexfec_stream) {
// TODO(brandtr): Update when we support multistream protection.
if (ssrcs.size() == 1) {
std::vector<uint32_t> flexfec_ssrcs;
GenerateSsrcs(*current_streams, 1, &flexfec_ssrcs);
stream_param.AddFecFrSsrc(ssrcs[0], flexfec_ssrcs[0]);
content_description->set_multistream(true);
} else if (!ssrcs.empty()) {
LOG(LS_WARNING)
<< "Our FlexFEC implementation only supports protecting "
<< "a single media streams. This session has multiple "
<< "media streams however, so no FlexFEC SSRC will be generated.";
}
}
stream_param.cname = rtcp_cname;
// TODO(steveanton): Support any number of stream ids.
RTC_CHECK(sender.stream_ids.size() == 1U);
stream_param.sync_label = sender.stream_ids[0];
content_description->AddStream(stream_param);
// Store the new StreamParams in current_streams.
// This is necessary so that we can use the CNAME for other media types.
current_streams->push_back(stream_param);
} else {
// Use existing generated SSRCs/groups, but update the sync_label if
// necessary. This may be needed if a MediaStreamTrack was moved from one
// MediaStream to another.
// TODO(steveanton): Support any number of stream ids.
RTC_CHECK(sender.stream_ids.size() == 1U);
param->sync_label = sender.stream_ids[0];
content_description->AddStream(*param);
}
}
return true;
}
// Updates the transport infos of the |sdesc| according to the given
// |bundle_group|. The transport infos of the content names within the
// |bundle_group| should be updated to use the ufrag, pwd and DTLS role of the
// first content within the |bundle_group|.
static bool UpdateTransportInfoForBundle(const ContentGroup& bundle_group,
SessionDescription* sdesc) {
// The bundle should not be empty.
if (!sdesc || !bundle_group.FirstContentName()) {
return false;
}
// We should definitely have a transport for the first content.
const std::string& selected_content_name = *bundle_group.FirstContentName();
const TransportInfo* selected_transport_info =
sdesc->GetTransportInfoByName(selected_content_name);
if (!selected_transport_info) {
return false;
}
// Set the other contents to use the same ICE credentials.
const std::string& selected_ufrag =
selected_transport_info->description.ice_ufrag;
const std::string& selected_pwd =
selected_transport_info->description.ice_pwd;
ConnectionRole selected_connection_role =
selected_transport_info->description.connection_role;
for (TransportInfos::iterator it =
sdesc->transport_infos().begin();
it != sdesc->transport_infos().end(); ++it) {
if (bundle_group.HasContentName(it->content_name) &&
it->content_name != selected_content_name) {
it->description.ice_ufrag = selected_ufrag;
it->description.ice_pwd = selected_pwd;
it->description.connection_role = selected_connection_role;
}
}
return true;
}
// Gets the CryptoParamsVec of the given |content_name| from |sdesc|, and
// sets it to |cryptos|.
static bool GetCryptosByName(const SessionDescription* sdesc,
const std::string& content_name,
CryptoParamsVec* cryptos) {
if (!sdesc || !cryptos) {
return false;
}
const ContentInfo* content = sdesc->GetContentByName(content_name);
if (!IsMediaContent(content) || !content->description) {
return false;
}
const MediaContentDescription* media_desc =
static_cast<const MediaContentDescription*>(content->description);
*cryptos = media_desc->cryptos();
return true;
}
// Predicate function used by the remove_if.
// Returns true if the |crypto|'s cipher_suite is not found in |filter|.
static bool CryptoNotFound(const CryptoParams crypto,
const CryptoParamsVec* filter) {
if (filter == NULL) {
return true;
}
for (CryptoParamsVec::const_iterator it = filter->begin();
it != filter->end(); ++it) {
if (it->cipher_suite == crypto.cipher_suite) {
return false;
}
}
return true;
}
// Prunes the |target_cryptos| by removing the crypto params (cipher_suite)
// which are not available in |filter|.
static void PruneCryptos(const CryptoParamsVec& filter,
CryptoParamsVec* target_cryptos) {
if (!target_cryptos) {
return;
}
target_cryptos->erase(std::remove_if(target_cryptos->begin(),
target_cryptos->end(),
bind2nd(ptr_fun(CryptoNotFound),
&filter)),
target_cryptos->end());
}
static bool IsRtpProtocol(const std::string& protocol) {
return protocol.empty() ||
(protocol.find(cricket::kMediaProtocolRtpPrefix) != std::string::npos);
}
static bool IsRtpContent(SessionDescription* sdesc,
const std::string& content_name) {
bool is_rtp = false;
ContentInfo* content = sdesc->GetContentByName(content_name);
if (IsMediaContent(content)) {
MediaContentDescription* media_desc =
static_cast<MediaContentDescription*>(content->description);
if (!media_desc) {
return false;
}
is_rtp = IsRtpProtocol(media_desc->protocol());
}
return is_rtp;
}
// Updates the crypto parameters of the |sdesc| according to the given
// |bundle_group|. The crypto parameters of all the contents within the
// |bundle_group| should be updated to use the common subset of the
// available cryptos.
static bool UpdateCryptoParamsForBundle(const ContentGroup& bundle_group,
SessionDescription* sdesc) {
// The bundle should not be empty.
if (!sdesc || !bundle_group.FirstContentName()) {
return false;
}
bool common_cryptos_needed = false;
// Get the common cryptos.
const ContentNames& content_names = bundle_group.content_names();
CryptoParamsVec common_cryptos;
for (ContentNames::const_iterator it = content_names.begin();
it != content_names.end(); ++it) {
if (!IsRtpContent(sdesc, *it)) {
continue;
}
// The common cryptos are needed if any of the content does not have DTLS
// enabled.
if (!sdesc->GetTransportInfoByName(*it)->description.secure()) {
common_cryptos_needed = true;
}
if (it == content_names.begin()) {
// Initial the common_cryptos with the first content in the bundle group.
if (!GetCryptosByName(sdesc, *it, &common_cryptos)) {
return false;
}
if (common_cryptos.empty()) {
// If there's no crypto params, we should just return.
return true;
}
} else {
CryptoParamsVec cryptos;
if (!GetCryptosByName(sdesc, *it, &cryptos)) {
return false;
}
PruneCryptos(cryptos, &common_cryptos);
}
}
if (common_cryptos.empty() && common_cryptos_needed) {
return false;
}
// Update to use the common cryptos.
for (ContentNames::const_iterator it = content_names.begin();
it != content_names.end(); ++it) {
if (!IsRtpContent(sdesc, *it)) {
continue;
}
ContentInfo* content = sdesc->GetContentByName(*it);
if (IsMediaContent(content)) {
MediaContentDescription* media_desc =
static_cast<MediaContentDescription*>(content->description);
if (!media_desc) {
return false;
}
media_desc->set_cryptos(common_cryptos);
}
}
return true;
}
template <class C>
static bool ContainsRtxCodec(const std::vector<C>& codecs) {
for (const auto& codec : codecs) {
if (IsRtxCodec(codec)) {
return true;
}
}
return false;
}
template <class C>
static bool IsRtxCodec(const C& codec) {
return STR_CASE_CMP(codec.name.c_str(), kRtxCodecName) == 0;
}
template <class C>
static bool ContainsFlexfecCodec(const std::vector<C>& codecs) {
for (const auto& codec : codecs) {
if (IsFlexfecCodec(codec)) {
return true;
}
}
return false;
}
template <class C>
static bool IsFlexfecCodec(const C& codec) {
return STR_CASE_CMP(codec.name.c_str(), kFlexfecCodecName) == 0;
}
// Create a media content to be offered for the given |sender_options|,
// according to the given options.rtcp_mux, session_options.is_muc, codecs,
// secure_transport, crypto, and current_streams. If we don't currently have
// crypto (in current_cryptos) and it is enabled (in secure_policy), crypto is
// created (according to crypto_suites). The created content is added to the
// offer.
template <class C>
static bool CreateMediaContentOffer(
const std::vector<SenderOptions>& sender_options,
const MediaSessionOptions& session_options,
const std::vector<C>& codecs,
const SecurePolicy& secure_policy,
const CryptoParamsVec* current_cryptos,
const std::vector<std::string>& crypto_suites,
const RtpHeaderExtensions& rtp_extensions,
StreamParamsVec* current_streams,
MediaContentDescriptionImpl<C>* offer) {
offer->AddCodecs(codecs);
offer->set_rtcp_mux(session_options.rtcp_mux_enabled);
if (offer->type() == cricket::MEDIA_TYPE_VIDEO) {
offer->set_rtcp_reduced_size(true);
}
offer->set_multistream(session_options.is_muc);
offer->set_rtp_header_extensions(rtp_extensions);
if (!AddStreamParams(sender_options, session_options.rtcp_cname,
current_streams, offer)) {
return false;
}
if (secure_policy != SEC_DISABLED) {
if (current_cryptos) {
AddMediaCryptos(*current_cryptos, offer);
}
if (offer->cryptos().empty()) {
if (!CreateMediaCryptos(crypto_suites, offer)) {
return false;
}
}
}
if (secure_policy == SEC_REQUIRED && offer->cryptos().empty()) {
return false;
}
return true;
}
template <class C>
static bool ReferencedCodecsMatch(const std::vector<C>& codecs1,
const int codec1_id,
const std::vector<C>& codecs2,
const int codec2_id) {
const C* codec1 = FindCodecById(codecs1, codec1_id);
const C* codec2 = FindCodecById(codecs2, codec2_id);
return codec1 != nullptr && codec2 != nullptr && codec1->Matches(*codec2);
}
template <class C>
static void NegotiateCodecs(const std::vector<C>& local_codecs,
const std::vector<C>& offered_codecs,
std::vector<C>* negotiated_codecs) {
for (const C& ours : local_codecs) {
C theirs;
// Note that we intentionally only find one matching codec for each of our
// local codecs, in case the remote offer contains duplicate codecs.
if (FindMatchingCodec(local_codecs, offered_codecs, ours, &theirs)) {
C negotiated = ours;
negotiated.IntersectFeedbackParams(theirs);
if (IsRtxCodec(negotiated)) {
const auto apt_it =
theirs.params.find(kCodecParamAssociatedPayloadType);
// FindMatchingCodec shouldn't return something with no apt value.
RTC_DCHECK(apt_it != theirs.params.end());
negotiated.SetParam(kCodecParamAssociatedPayloadType, apt_it->second);
}
if (CodecNamesEq(ours.name.c_str(), kH264CodecName)) {
webrtc::H264::GenerateProfileLevelIdForAnswer(
ours.params, theirs.params, &negotiated.params);
}
negotiated.id = theirs.id;
negotiated.name = theirs.name;
negotiated_codecs->push_back(std::move(negotiated));
}
}
// RFC3264: Although the answerer MAY list the formats in their desired
// order of preference, it is RECOMMENDED that unless there is a
// specific reason, the answerer list formats in the same relative order
// they were present in the offer.
std::unordered_map<int, int> payload_type_preferences;
int preference = static_cast<int>(offered_codecs.size() + 1);
for (const C& codec : offered_codecs) {
payload_type_preferences[codec.id] = preference--;
}
std::sort(negotiated_codecs->begin(), negotiated_codecs->end(),
[&payload_type_preferences](const C& a, const C& b) {
return payload_type_preferences[a.id] >
payload_type_preferences[b.id];
});
}
// Finds a codec in |codecs2| that matches |codec_to_match|, which is
// a member of |codecs1|. If |codec_to_match| is an RTX codec, both
// the codecs themselves and their associated codecs must match.
template <class C>
static bool FindMatchingCodec(const std::vector<C>& codecs1,
const std::vector<C>& codecs2,
const C& codec_to_match,
C* found_codec) {
// |codec_to_match| should be a member of |codecs1|, in order to look up RTX
// codecs' associated codecs correctly. If not, that's a programming error.
RTC_DCHECK(std::find_if(codecs1.begin(), codecs1.end(),
[&codec_to_match](const C& codec) {
return &codec == &codec_to_match;
}) != codecs1.end());
for (const C& potential_match : codecs2) {
if (potential_match.Matches(codec_to_match)) {
if (IsRtxCodec(codec_to_match)) {
int apt_value_1 = 0;
int apt_value_2 = 0;
if (!codec_to_match.GetParam(kCodecParamAssociatedPayloadType,
&apt_value_1) ||
!potential_match.GetParam(kCodecParamAssociatedPayloadType,
&apt_value_2)) {
LOG(LS_WARNING) << "RTX missing associated payload type.";
continue;
}
if (!ReferencedCodecsMatch(codecs1, apt_value_1, codecs2,
apt_value_2)) {
continue;
}
}
if (found_codec) {
*found_codec = potential_match;
}
return true;
}
}
return false;
}
// Find the codec in |codec_list| that |rtx_codec| is associated with.
template <class C>
static const C* GetAssociatedCodec(const std::vector<C>& codec_list,
const C& rtx_codec) {
std::string associated_pt_str;
if (!rtx_codec.GetParam(kCodecParamAssociatedPayloadType,
&associated_pt_str)) {
LOG(LS_WARNING) << "RTX codec " << rtx_codec.name
<< " is missing an associated payload type.";
return nullptr;
}
int associated_pt;
if (!rtc::FromString(associated_pt_str, &associated_pt)) {
LOG(LS_WARNING) << "Couldn't convert payload type " << associated_pt_str
<< " of RTX codec " << rtx_codec.name << " to an integer.";
return nullptr;
}
// Find the associated reference codec for the reference RTX codec.
const C* associated_codec = FindCodecById(codec_list, associated_pt);
if (!associated_codec) {
LOG(LS_WARNING) << "Couldn't find associated codec with payload type "
<< associated_pt << " for RTX codec " << rtx_codec.name
<< ".";
}
return associated_codec;
}
// Adds all codecs from |reference_codecs| to |offered_codecs| that don't
// already exist in |offered_codecs| and ensure the payload types don't
// collide.
template <class C>
static void MergeCodecs(const std::vector<C>& reference_codecs,
std::vector<C>* offered_codecs,
UsedPayloadTypes* used_pltypes) {
// Add all new codecs that are not RTX codecs.
for (const C& reference_codec : reference_codecs) {
if (!IsRtxCodec(reference_codec) &&
!FindMatchingCodec<C>(reference_codecs, *offered_codecs,
reference_codec, nullptr)) {
C codec = reference_codec;
used_pltypes->FindAndSetIdUsed(&codec);
offered_codecs->push_back(codec);
}
}
// Add all new RTX codecs.
for (const C& reference_codec : reference_codecs) {
if (IsRtxCodec(reference_codec) &&
!FindMatchingCodec<C>(reference_codecs, *offered_codecs,
reference_codec, nullptr)) {
C rtx_codec = reference_codec;
const C* associated_codec =
GetAssociatedCodec(reference_codecs, rtx_codec);
if (!associated_codec) {
continue;
}
// Find a codec in the offered list that matches the reference codec.
// Its payload type may be different than the reference codec.
C matching_codec;
if (!FindMatchingCodec<C>(reference_codecs, *offered_codecs,
*associated_codec, &matching_codec)) {
LOG(LS_WARNING) << "Couldn't find matching " << associated_codec->name
<< " codec.";
continue;
}
rtx_codec.params[kCodecParamAssociatedPayloadType] =
rtc::ToString(matching_codec.id);
used_pltypes->FindAndSetIdUsed(&rtx_codec);
offered_codecs->push_back(rtx_codec);
}
}
}
static bool FindByUriAndEncryption(const RtpHeaderExtensions& extensions,
const webrtc::RtpExtension& ext_to_match,
webrtc::RtpExtension* found_extension) {
for (RtpHeaderExtensions::const_iterator it = extensions.begin();
it != extensions.end(); ++it) {
// We assume that all URIs are given in a canonical format.
if (it->uri == ext_to_match.uri && it->encrypt == ext_to_match.encrypt) {
if (found_extension) {
*found_extension = *it;
}
return true;
}
}
return false;
}
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,
const webrtc::RtpExtension& ext_to_match, bool encryption_preference,
webrtc::RtpExtension* found_extension) {
const webrtc::RtpExtension* unencrypted_extension = nullptr;
for (RtpHeaderExtensions::const_iterator it = extensions.begin();
it != extensions.end(); ++it) {
// We assume that all URIs are given in a canonical format.
if (it->uri == ext_to_match.uri) {
if (!encryption_preference || it->encrypt) {
if (found_extension) {
*found_extension = *it;
}
return true;
}
unencrypted_extension = &(*it);
}
}
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
// |encrypted_extensions|, and if the extension is in |regular_extensions| or
// |encrypted_extensions|, its ID is marked as used in |used_ids|.
// |offered_extensions| is for either audio or video while |regular_extensions|
// and |encrypted_extensions| are used for both audio and video. There could be
// overlap between audio extensions and video extensions.
static void MergeRtpHdrExts(const RtpHeaderExtensions& reference_extensions,
RtpHeaderExtensions* offered_extensions,
RtpHeaderExtensions* regular_extensions,
RtpHeaderExtensions* encrypted_extensions,
UsedRtpHeaderExtensionIds* used_ids) {
for (auto reference_extension : reference_extensions) {
if (!FindByUriAndEncryption(*offered_extensions, reference_extension,
nullptr)) {
webrtc::RtpExtension existing;
if (reference_extension.encrypt) {
if (FindByUriAndEncryption(*encrypted_extensions, reference_extension,
&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);
} else {
used_ids->FindAndSetIdUsed(&reference_extension);
regular_extensions->push_back(reference_extension);
offered_extensions->push_back(reference_extension);
}
}
}
}
}
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, true,
&existing) && existing.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);
}
}
extensions->insert(extensions->end(), encrypted_extensions.begin(),
encrypted_extensions.end());
}
static void NegotiateRtpHeaderExtensions(
const RtpHeaderExtensions& local_extensions,
const RtpHeaderExtensions& offered_extensions,
bool enable_encrypted_rtp_header_extensions,
RtpHeaderExtensions* negotiated_extenstions) {
RtpHeaderExtensions::const_iterator ours;
for (ours = local_extensions.begin();
ours != local_extensions.end(); ++ours) {
webrtc::RtpExtension theirs;
if (FindByUriWithEncryptionPreference(offered_extensions, *ours,
enable_encrypted_rtp_header_extensions, &theirs)) {
// We respond with their RTP header extension id.
negotiated_extenstions->push_back(theirs);
}
}
}
static void StripCNCodecs(AudioCodecs* audio_codecs) {
AudioCodecs::iterator iter = audio_codecs->begin();
while (iter != audio_codecs->end()) {
if (STR_CASE_CMP(iter->name.c_str(), kComfortNoiseCodecName) == 0) {
iter = audio_codecs->erase(iter);
} else {
++iter;
}
}
}
// Create a media content to be answered for the given |sender_options|
// according to the given session_options.rtcp_mux, session_options.streams,
// codecs, crypto, and current_streams. If we don't currently have crypto (in
// current_cryptos) and it is enabled (in secure_policy), crypto is created
// (according to crypto_suites). The codecs, rtcp_mux, and crypto are all
// negotiated with the offer. If the negotiation fails, this method returns
// false. The created content is added to the offer.
template <class C>
static bool CreateMediaContentAnswer(
const MediaContentDescriptionImpl<C>* offer,
const MediaDescriptionOptions& media_description_options,
const MediaSessionOptions& session_options,
const std::vector<C>& local_codecs,
const SecurePolicy& sdes_policy,
const CryptoParamsVec* current_cryptos,
const RtpHeaderExtensions& local_rtp_extenstions,
bool enable_encrypted_rtp_header_extensions,
StreamParamsVec* current_streams,
bool bundle_enabled,
MediaContentDescriptionImpl<C>* answer) {
std::vector<C> negotiated_codecs;
NegotiateCodecs(local_codecs, offer->codecs(), &negotiated_codecs);
answer->AddCodecs(negotiated_codecs);
answer->set_protocol(offer->protocol());
RtpHeaderExtensions negotiated_rtp_extensions;
NegotiateRtpHeaderExtensions(local_rtp_extenstions,
offer->rtp_header_extensions(),
enable_encrypted_rtp_header_extensions,
&negotiated_rtp_extensions);
answer->set_rtp_header_extensions(negotiated_rtp_extensions);
answer->set_rtcp_mux(session_options.rtcp_mux_enabled && offer->rtcp_mux());
if (answer->type() == cricket::MEDIA_TYPE_VIDEO) {
answer->set_rtcp_reduced_size(offer->rtcp_reduced_size());
}
if (sdes_policy != SEC_DISABLED) {
CryptoParams crypto;
if (SelectCrypto(offer, bundle_enabled, session_options.crypto_options,
&crypto)) {
if (current_cryptos) {
FindMatchingCrypto(*current_cryptos, crypto, &crypto);
}
answer->AddCrypto(crypto);
}
}
if (answer->cryptos().empty() && sdes_policy == SEC_REQUIRED) {
return false;
}
if (!AddStreamParams(media_description_options.sender_options,
session_options.rtcp_cname, current_streams, answer)) {
return false; // Something went seriously wrong.
}
auto offer_rtd =
RtpTransceiverDirection::FromMediaContentDirection(offer->direction());
answer->set_direction(NegotiateRtpTransceiverDirection(
offer_rtd, media_description_options.direction)
.ToMediaContentDirection());
return true;
}
static bool IsMediaProtocolSupported(MediaType type,
const std::string& protocol,
bool secure_transport) {
// Since not all applications serialize and deserialize the media protocol,
// we will have to accept |protocol| to be empty.
if (protocol.empty()) {
return true;
}
if (type == MEDIA_TYPE_DATA) {
// Check for SCTP, but also for RTP for RTP-based data channels.
// TODO(pthatcher): Remove RTP once RTP-based data channels are gone.
if (secure_transport) {
// Most likely scenarios first.
return IsDtlsSctp(protocol) || IsDtlsRtp(protocol) ||
IsPlainRtp(protocol);
} else {
return IsPlainSctp(protocol) || IsPlainRtp(protocol);
}
}
// Allow for non-DTLS RTP protocol even when using DTLS because that's what
// JSEP specifies.
if (secure_transport) {
// Most likely scenarios first.
return IsDtlsRtp(protocol) || IsPlainRtp(protocol);
} else {
return IsPlainRtp(protocol);
}
}
static void SetMediaProtocol(bool secure_transport,
MediaContentDescription* desc) {
if (!desc->cryptos().empty())
desc->set_protocol(kMediaProtocolSavpf);
else if (secure_transport)
desc->set_protocol(kMediaProtocolDtlsSavpf);
else
desc->set_protocol(kMediaProtocolAvpf);
}
// Gets the TransportInfo of the given |content_name| from the
// |current_description|. If doesn't exist, returns a new one.
static const TransportDescription* GetTransportDescription(
const std::string& content_name,
const SessionDescription* current_description) {
const TransportDescription* desc = NULL;
if (current_description) {
const TransportInfo* info =
current_description->GetTransportInfoByName(content_name);
if (info) {
desc = &info->description;
}
}
return desc;
}
// Gets the current DTLS state from the transport description.
static bool IsDtlsActive(const ContentInfo* content,
const SessionDescription* current_description) {
if (!content) {
return false;
}
size_t msection_index = content - &current_description->contents()[0];
if (current_description->transport_infos().size() <= msection_index) {
return false;
}
return current_description->transport_infos()[msection_index]
.description.secure();
}
std::string MediaContentDirectionToString(MediaContentDirection direction) {
std::string dir_str;
switch (direction) {
case MD_INACTIVE:
dir_str = "inactive";
break;
case MD_SENDONLY:
dir_str = "sendonly";
break;
case MD_RECVONLY:
dir_str = "recvonly";
break;
case MD_SENDRECV:
dir_str = "sendrecv";
break;
default:
RTC_NOTREACHED();
break;
}
return dir_str;
}
void MediaDescriptionOptions::AddAudioSender(
const std::string& track_id,
const std::vector<std::string>& stream_ids) {
RTC_DCHECK(type == MEDIA_TYPE_AUDIO);
AddSenderInternal(track_id, stream_ids, 1);
}
void MediaDescriptionOptions::AddVideoSender(
const std::string& track_id,
const std::vector<std::string>& stream_ids,
int num_sim_layers) {
RTC_DCHECK(type == MEDIA_TYPE_VIDEO);
AddSenderInternal(track_id, stream_ids, num_sim_layers);
}
void MediaDescriptionOptions::AddRtpDataChannel(const std::string& track_id,
const std::string& stream_id) {
RTC_DCHECK(type == MEDIA_TYPE_DATA);
// TODO(steveanton): Is it the case that RtpDataChannel will never have more
// than one stream?
AddSenderInternal(track_id, {stream_id}, 1);
}
void MediaDescriptionOptions::AddSenderInternal(
const std::string& track_id,
const std::vector<std::string>& stream_ids,
int num_sim_layers) {
// TODO(steveanton): Support any number of stream ids.
RTC_CHECK(stream_ids.size() == 1U);
sender_options.push_back(SenderOptions{track_id, stream_ids, num_sim_layers});
}
bool MediaSessionOptions::HasMediaDescription(MediaType type) const {
return std::find_if(media_description_options.begin(),
media_description_options.end(),
[type](const MediaDescriptionOptions& t) {
return t.type == type;
}) != media_description_options.end();
}
MediaSessionDescriptionFactory::MediaSessionDescriptionFactory(
const TransportDescriptionFactory* transport_desc_factory)
: transport_desc_factory_(transport_desc_factory) {}
MediaSessionDescriptionFactory::MediaSessionDescriptionFactory(
ChannelManager* channel_manager,
const TransportDescriptionFactory* transport_desc_factory)
: transport_desc_factory_(transport_desc_factory) {
channel_manager->GetSupportedAudioSendCodecs(&audio_send_codecs_);
channel_manager->GetSupportedAudioReceiveCodecs(&audio_recv_codecs_);
channel_manager->GetSupportedAudioRtpHeaderExtensions(&audio_rtp_extensions_);
channel_manager->GetSupportedVideoCodecs(&video_codecs_);
channel_manager->GetSupportedVideoRtpHeaderExtensions(&video_rtp_extensions_);
channel_manager->GetSupportedDataCodecs(&data_codecs_);
ComputeAudioCodecsIntersectionAndUnion();
}
const AudioCodecs& MediaSessionDescriptionFactory::audio_sendrecv_codecs()
const {
return audio_sendrecv_codecs_;
}
const AudioCodecs& MediaSessionDescriptionFactory::audio_send_codecs() const {
return audio_send_codecs_;
}
const AudioCodecs& MediaSessionDescriptionFactory::audio_recv_codecs() const {
return audio_recv_codecs_;
}
void MediaSessionDescriptionFactory::set_audio_codecs(
const AudioCodecs& send_codecs, const AudioCodecs& recv_codecs) {
audio_send_codecs_ = send_codecs;
audio_recv_codecs_ = recv_codecs;
ComputeAudioCodecsIntersectionAndUnion();
}
SessionDescription* MediaSessionDescriptionFactory::CreateOffer(
const MediaSessionOptions& session_options,
const SessionDescription* current_description) const {
std::unique_ptr<SessionDescription> offer(new SessionDescription());
StreamParamsVec current_streams;
GetCurrentStreamParams(current_description, &current_streams);
AudioCodecs offer_audio_codecs;
VideoCodecs offer_video_codecs;
DataCodecs offer_data_codecs;
GetCodecsForOffer(current_description, &offer_audio_codecs,
&offer_video_codecs, &offer_data_codecs);
if (!session_options.vad_enabled) {
// If application doesn't want CN codecs in offer.
StripCNCodecs(&offer_audio_codecs);
}
FilterDataCodecs(&offer_data_codecs,
session_options.data_channel_type == DCT_SCTP);
RtpHeaderExtensions audio_rtp_extensions;
RtpHeaderExtensions video_rtp_extensions;
GetRtpHdrExtsToOffer(current_description, &audio_rtp_extensions,
&video_rtp_extensions);
// Must have options for each existing section.
if (current_description) {
RTC_DCHECK(current_description->contents().size() <=
session_options.media_description_options.size());
}
// Iterate through the media description options, matching with existing media
// descriptions in |current_description|.
int msection_index = 0;
for (const MediaDescriptionOptions& media_description_options :
session_options.media_description_options) {
const ContentInfo* current_content = nullptr;
if (current_description &&
msection_index <
static_cast<int>(current_description->contents().size())) {
current_content = &current_description->contents()[msection_index];
// Media type must match.
RTC_DCHECK(IsMediaContentOfType(current_content,
media_description_options.type));
}
switch (media_description_options.type) {
case MEDIA_TYPE_AUDIO:
if (!AddAudioContentForOffer(media_description_options, session_options,
current_content, current_description,
audio_rtp_extensions, offer_audio_codecs,
&current_streams, offer.get())) {
return nullptr;
}
break;
case MEDIA_TYPE_VIDEO:
if (!AddVideoContentForOffer(media_description_options, session_options,
current_content, current_description,
video_rtp_extensions, offer_video_codecs,
&current_streams, offer.get())) {
return nullptr;
}
break;
case MEDIA_TYPE_DATA:
if (!AddDataContentForOffer(media_description_options, session_options,
current_content, current_description,
offer_data_codecs, &current_streams,
offer.get())) {
return nullptr;
}
break;
default:
RTC_NOTREACHED();
}
++msection_index;
}
// Bundle the contents together, if we've been asked to do so, and update any
// parameters that need to be tweaked for BUNDLE.
if (session_options.bundle_enabled && offer->contents().size() > 0u) {
ContentGroup offer_bundle(GROUP_TYPE_BUNDLE);
for (const ContentInfo& content : offer->contents()) {
// TODO(deadbeef): There are conditions that make bundling two media
// descriptions together illegal. For example, they use the same payload
// type to represent different codecs, or same IDs for different header
// extensions. We need to detect this and not try to bundle those media
// descriptions together.
offer_bundle.AddContentName(content.name);
}
offer->AddGroup(offer_bundle);
if (!UpdateTransportInfoForBundle(offer_bundle, offer.get())) {
LOG(LS_ERROR) << "CreateOffer failed to UpdateTransportInfoForBundle.";
return nullptr;
}
if (!UpdateCryptoParamsForBundle(offer_bundle, offer.get())) {
LOG(LS_ERROR) << "CreateOffer failed to UpdateCryptoParamsForBundle.";
return nullptr;
}
}
return offer.release();
}
SessionDescription* MediaSessionDescriptionFactory::CreateAnswer(
const SessionDescription* offer,
const MediaSessionOptions& session_options,
const SessionDescription* current_description) const {
if (!offer) {
return nullptr;
}
// The answer contains the intersection of the codecs in the offer with the
// codecs we support. As indicated by XEP-0167, we retain the same payload ids
// from the offer in the answer.
std::unique_ptr<SessionDescription> answer(new SessionDescription());
StreamParamsVec current_streams;
GetCurrentStreamParams(current_description, &current_streams);
// 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;
// Get list of all possible codecs that respects existing payload type
// mappings and uses a single payload type space.
//
// Note that these lists may be further filtered for each m= section; this
// step is done just to establish the payload type mappings shared by all
// sections.
AudioCodecs answer_audio_codecs;
VideoCodecs answer_video_codecs;
DataCodecs answer_data_codecs;
GetCodecsForAnswer(current_description, offer, &answer_audio_codecs,
&answer_video_codecs, &answer_data_codecs);
if (!session_options.vad_enabled) {
// If application doesn't want CN codecs in answer.
StripCNCodecs(&answer_audio_codecs);
}
FilterDataCodecs(&answer_data_codecs,
session_options.data_channel_type == DCT_SCTP);
// Must have options for exactly as many sections as in the offer.
RTC_DCHECK(offer->contents().size() ==
session_options.media_description_options.size());
// Iterate through the media description options, matching with existing
// media descriptions in |current_description|.
int msection_index = 0;
for (const MediaDescriptionOptions& media_description_options :
session_options.media_description_options) {
const ContentInfo* offer_content = &offer->contents()[msection_index];
// Media types and MIDs must match between the remote offer and the
// MediaDescriptionOptions.
RTC_DCHECK(
IsMediaContentOfType(offer_content, media_description_options.type));
RTC_DCHECK(media_description_options.mid == offer_content->name);
const ContentInfo* current_content = nullptr;
if (current_description &&
msection_index <
static_cast<int>(current_description->contents().size())) {
current_content = &current_description->contents()[msection_index];
}
switch (media_description_options.type) {
case MEDIA_TYPE_AUDIO:
if (!AddAudioContentForAnswer(
media_description_options, session_options, offer_content,
offer, current_content, current_description,
bundle_transport.get(), answer_audio_codecs, &current_streams,
answer.get())) {
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, &current_streams,
answer.get())) {
return nullptr;
}
break;
case MEDIA_TYPE_DATA:
if (!AddDataContentForAnswer(media_description_options, session_options,
offer_content, offer, current_content,
current_description,
bundle_transport.get(), answer_data_codecs,
&current_streams, answer.get())) {
return nullptr;
}
break;
default:
RTC_NOTREACHED();
}
++msection_index;
// 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(
new TransportInfo(*answer->GetTransportInfoByName(added.name)));
}
}
// Only put BUNDLE group in answer if nonempty.
if (answer_bundle.FirstContentName()) {
answer->AddGroup(answer_bundle);
// Share the same ICE credentials and crypto params across all contents,
// as BUNDLE requires.
if (!UpdateTransportInfoForBundle(answer_bundle, answer.get())) {
LOG(LS_ERROR) << "CreateAnswer failed to UpdateTransportInfoForBundle.";
return NULL;
}
if (!UpdateCryptoParamsForBundle(answer_bundle, answer.get())) {
LOG(LS_ERROR) << "CreateAnswer failed to UpdateCryptoParamsForBundle.";
return NULL;
}
}
return answer.release();
}
const AudioCodecs& MediaSessionDescriptionFactory::GetAudioCodecsForOffer(
const RtpTransceiverDirection& direction) const {
// If stream is inactive - generate list as if sendrecv.
if (direction.send == direction.recv) {
return audio_sendrecv_codecs_;
} else if (direction.send) {
return audio_send_codecs_;
} else {
return audio_recv_codecs_;
}
}
const AudioCodecs& MediaSessionDescriptionFactory::GetAudioCodecsForAnswer(
const RtpTransceiverDirection& offer,
const RtpTransceiverDirection& answer) const {
// For inactive and sendrecv answers, generate lists as if we were to accept
// the offer's direction. See RFC 3264 Section 6.1.
if (answer.send == answer.recv) {
if (offer.send == offer.recv) {
return audio_sendrecv_codecs_;
} else if (offer.send) {
return audio_recv_codecs_;
} else {
return audio_send_codecs_;
}
} else if (answer.send) {
return audio_send_codecs_;
} else {
return audio_recv_codecs_;
}
}
void MergeCodecsFromDescription(const SessionDescription* description,
AudioCodecs* audio_codecs,
VideoCodecs* video_codecs,
DataCodecs* data_codecs,
UsedPayloadTypes* used_pltypes) {
RTC_DCHECK(description);
for (const ContentInfo& content : description->contents()) {
if (IsMediaContentOfType(&content, MEDIA_TYPE_AUDIO)) {
const AudioContentDescription* audio =
static_cast<AudioContentDescription*>(content.description);
MergeCodecs<AudioCodec>(audio->codecs(), audio_codecs, used_pltypes);
} else if (IsMediaContentOfType(&content, MEDIA_TYPE_VIDEO)) {
const VideoContentDescription* video =
static_cast<VideoContentDescription*>(content.description);
MergeCodecs<VideoCodec>(video->codecs(), video_codecs, used_pltypes);
} else if (IsMediaContentOfType(&content, MEDIA_TYPE_DATA)) {
const DataContentDescription* data =
static_cast<DataContentDescription*>(content.description);
MergeCodecs<DataCodec>(data->codecs(), data_codecs, used_pltypes);
}
}
}
// Getting codecs for an offer involves these steps:
//
// 1. Construct payload type -> codec mappings for current description.
// 2. Add any reference codecs that weren't already present
// 3. For each individual media description (m= section), filter codecs based
// on the directional attribute (happens in another method).
void MediaSessionDescriptionFactory::GetCodecsForOffer(
const SessionDescription* current_description,
AudioCodecs* audio_codecs,
VideoCodecs* video_codecs,
DataCodecs* data_codecs) const {
UsedPayloadTypes used_pltypes;
audio_codecs->clear();
video_codecs->clear();
data_codecs->clear();
// First - get all codecs from the current description if the media type
// is used. Add them to |used_pltypes| so the payload type is not reused if a
// new media type is added.
if (current_description) {
MergeCodecsFromDescription(current_description, audio_codecs, video_codecs,
data_codecs, &used_pltypes);
}
// Add our codecs that are not in |current_description|.
MergeCodecs<AudioCodec>(all_audio_codecs_, audio_codecs, &used_pltypes);
MergeCodecs<VideoCodec>(video_codecs_, video_codecs, &used_pltypes);
MergeCodecs<DataCodec>(data_codecs_, data_codecs, &used_pltypes);
}
// Getting codecs for an answer involves these steps:
//
// 1. Construct payload type -> codec mappings for current description.
// 2. Add any codecs from the offer that weren't already present.
// 3. Add any remaining codecs that weren't already present.
// 4. For each individual media description (m= section), filter codecs based
// on the directional attribute (happens in another method).
void MediaSessionDescriptionFactory::GetCodecsForAnswer(
const SessionDescription* current_description,
const SessionDescription* remote_offer,
AudioCodecs* audio_codecs,
VideoCodecs* video_codecs,
DataCodecs* data_codecs) const {
UsedPayloadTypes used_pltypes;
audio_codecs->clear();
video_codecs->clear();
data_codecs->clear();
// First - get all codecs from the current description if the media type
// is used. Add them to |used_pltypes| so the payload type is not reused if a
// new media type is added.
if (current_description) {
MergeCodecsFromDescription(current_description, audio_codecs, video_codecs,
data_codecs, &used_pltypes);
}
// Second - filter out codecs that we don't support at all and should ignore.
AudioCodecs filtered_offered_audio_codecs;
VideoCodecs filtered_offered_video_codecs;
DataCodecs filtered_offered_data_codecs;
for (const ContentInfo& content : remote_offer->contents()) {
if (IsMediaContentOfType(&content, MEDIA_TYPE_AUDIO)) {
const AudioContentDescription* audio =
static_cast<AudioContentDescription*>(content.description);
for (const AudioCodec& offered_audio_codec : audio->codecs()) {
if (!FindMatchingCodec<AudioCodec>(audio->codecs(),
filtered_offered_audio_codecs,
offered_audio_codec, nullptr) &&
FindMatchingCodec<AudioCodec>(audio->codecs(), all_audio_codecs_,
offered_audio_codec, nullptr)) {
filtered_offered_audio_codecs.push_back(offered_audio_codec);
}
}
} else if (IsMediaContentOfType(&content, MEDIA_TYPE_VIDEO)) {
const VideoContentDescription* video =
static_cast<VideoContentDescription*>(content.description);
for (const VideoCodec& offered_video_codec : video->codecs()) {
if (!FindMatchingCodec<VideoCodec>(video->codecs(),
filtered_offered_video_codecs,
offered_video_codec, nullptr) &&
FindMatchingCodec<VideoCodec>(video->codecs(), video_codecs_,
offered_video_codec, nullptr)) {
filtered_offered_video_codecs.push_back(offered_video_codec);
}
}
} else if (IsMediaContentOfType(&content, MEDIA_TYPE_DATA)) {
const DataContentDescription* data =
static_cast<DataContentDescription*>(content.description);
for (const DataCodec& offered_data_codec : data->codecs()) {
if (!FindMatchingCodec<DataCodec>(data->codecs(),
filtered_offered_data_codecs,
offered_data_codec, nullptr) &&
FindMatchingCodec<DataCodec>(data->codecs(), data_codecs_,
offered_data_codec, nullptr)) {
filtered_offered_data_codecs.push_back(offered_data_codec);
}
}
}
}
// Add codecs that are not in |current_description| but were in
// |remote_offer|.
MergeCodecs<AudioCodec>(filtered_offered_audio_codecs, audio_codecs,
&used_pltypes);
MergeCodecs<VideoCodec>(filtered_offered_video_codecs, video_codecs,
&used_pltypes);
MergeCodecs<DataCodec>(filtered_offered_data_codecs, data_codecs,
&used_pltypes);
}
void MediaSessionDescriptionFactory::GetRtpHdrExtsToOffer(
const SessionDescription* current_description,
RtpHeaderExtensions* offer_audio_extensions,
RtpHeaderExtensions* offer_video_extensions) const {
// All header extensions allocated from the same range to avoid potential
// issues when using BUNDLE.
UsedRtpHeaderExtensionIds used_ids;
RtpHeaderExtensions all_regular_extensions;
RtpHeaderExtensions all_encrypted_extensions;
offer_audio_extensions->clear();
offer_video_extensions->clear();
// First - get all extensions from the current description if the media type
// is used.
// Add them to |used_ids| so the local ids are not reused if a new media
// type is added.
if (current_description) {
for (const ContentInfo& content : current_description->contents()) {
if (IsMediaContentOfType(&content, MEDIA_TYPE_AUDIO)) {
const AudioContentDescription* audio =
static_cast<const AudioContentDescription*>(content.description);
MergeRtpHdrExts(audio->rtp_header_extensions(), offer_audio_extensions,
&all_regular_extensions, &all_encrypted_extensions,
&used_ids);
} else if (IsMediaContentOfType(&content, MEDIA_TYPE_VIDEO)) {
const VideoContentDescription* video =
static_cast<const VideoContentDescription*>(content.description);
MergeRtpHdrExts(video->rtp_header_extensions(), offer_video_extensions,
&all_regular_extensions, &all_encrypted_extensions,
&used_ids);
}
}
}
// Add our default RTP header extensions that are not in
// |current_description|.
MergeRtpHdrExts(audio_rtp_header_extensions(), offer_audio_extensions,
&all_regular_extensions, &all_encrypted_extensions,
&used_ids);
MergeRtpHdrExts(video_rtp_header_extensions(), offer_video_extensions,
&all_regular_extensions, &all_encrypted_extensions,
&used_ids);
// TODO(jbauch): Support adding encrypted header extensions to existing
// sessions.
if (enable_encrypted_rtp_header_extensions_ && !current_description) {
AddEncryptedVersionsOfHdrExts(offer_audio_extensions,
&all_encrypted_extensions, &used_ids);
AddEncryptedVersionsOfHdrExts(offer_video_extensions,
&all_encrypted_extensions, &used_ids);
}
}
bool MediaSessionDescriptionFactory::AddTransportOffer(
const std::string& content_name,
const TransportOptions& transport_options,
const SessionDescription* current_desc,
SessionDescription* offer_desc) const {
if (!transport_desc_factory_)
return false;
const TransportDescription* current_tdesc =
GetTransportDescription(content_name, current_desc);
std::unique_ptr<TransportDescription> new_tdesc(
transport_desc_factory_->CreateOffer(transport_options, current_tdesc));
bool ret = (new_tdesc.get() != NULL &&
offer_desc->AddTransportInfo(TransportInfo(content_name, *new_tdesc)));
if (!ret) {
LOG(LS_ERROR)
<< "Failed to AddTransportOffer, content name=" << content_name;
}
return ret;
}
TransportDescription* MediaSessionDescriptionFactory::CreateTransportAnswer(
const std::string& content_name,
const SessionDescription* offer_desc,
const TransportOptions& transport_options,
const SessionDescription* current_desc,
bool require_transport_attributes) const {
if (!transport_desc_factory_)
return NULL;
const TransportDescription* offer_tdesc =
GetTransportDescription(content_name, offer_desc);
const TransportDescription* current_tdesc =
GetTransportDescription(content_name, current_desc);
return transport_desc_factory_->CreateAnswer(offer_tdesc, transport_options,
require_transport_attributes,
current_tdesc);
}
bool MediaSessionDescriptionFactory::AddTransportAnswer(
const std::string& content_name,
const TransportDescription& transport_desc,
SessionDescription* answer_desc) const {
if (!answer_desc->AddTransportInfo(TransportInfo(content_name,
transport_desc))) {
LOG(LS_ERROR)
<< "Failed to AddTransportAnswer, content name=" << content_name;
return false;
}
return true;
}
// |audio_codecs| = set of all possible codecs that can be used, with correct
// payload type mappings
//
// |supported_audio_codecs| = set of codecs that are supported for the direction
// of this m= section
//
// acd->codecs() = set of previously negotiated codecs for this m= section
//
// The payload types should come from audio_codecs, but the order should come
// from acd->codecs() and then supported_codecs, to ensure that re-offers don't
// change existing codec priority, and that new codecs are added with the right
// priority.
bool MediaSessionDescriptionFactory::AddAudioContentForOffer(
const MediaDescriptionOptions& media_description_options,
const MediaSessionOptions& session_options,
const ContentInfo* current_content,
const SessionDescription* current_description,
const RtpHeaderExtensions& audio_rtp_extensions,
const AudioCodecs& audio_codecs,
StreamParamsVec* current_streams,
SessionDescription* desc) const {
// Filter audio_codecs (which includes all codecs, with correctly remapped
// payload types) based on transceiver direction.
const AudioCodecs& supported_audio_codecs =
GetAudioCodecsForOffer(media_description_options.direction);
AudioCodecs filtered_codecs;
// Add the codecs from current content if exists.
if (current_content) {
RTC_CHECK(IsMediaContentOfType(current_content, MEDIA_TYPE_AUDIO));
const AudioContentDescription* acd =
static_cast<const AudioContentDescription*>(
current_content->description);
for (const AudioCodec& codec : acd->codecs()) {
if (FindMatchingCodec<AudioCodec>(acd->codecs(), audio_codecs, codec,
nullptr)) {
filtered_codecs.push_back(codec);
}
}
}
// Add other supported audio codecs.
AudioCodec found_codec;
for (const AudioCodec& codec : supported_audio_codecs) {
if (FindMatchingCodec<AudioCodec>(supported_audio_codecs, audio_codecs,
codec, &found_codec) &&
!FindMatchingCodec<AudioCodec>(supported_audio_codecs, filtered_codecs,
codec, nullptr)) {
// Use the |found_codec| from |audio_codecs| because it has the correctly
// mapped payload type.
filtered_codecs.push_back(found_codec);
}
}
cricket::SecurePolicy sdes_policy =
IsDtlsActive(current_content, current_description) ? cricket::SEC_DISABLED
: secure();
std::unique_ptr<AudioContentDescription> audio(new AudioContentDescription());
std::vector<std::string> crypto_suites;
GetSupportedAudioSdesCryptoSuiteNames(session_options.crypto_options,
&crypto_suites);
if (!CreateMediaContentOffer(
media_description_options.sender_options, session_options,
filtered_codecs, sdes_policy, GetCryptos(current_content),
crypto_suites, audio_rtp_extensions, current_streams, audio.get())) {
return false;
}
audio->set_lang(lang_);
bool secure_transport = (transport_desc_factory_->secure() != SEC_DISABLED);
SetMediaProtocol(secure_transport, audio.get());
audio->set_direction(
media_description_options.direction.ToMediaContentDirection());
desc->AddContent(media_description_options.mid, NS_JINGLE_RTP,
media_description_options.stopped, audio.release());
if (!AddTransportOffer(media_description_options.mid,
media_description_options.transport_options,
current_description, desc)) {
return false;
}
return true;
}
bool MediaSessionDescriptionFactory::AddVideoContentForOffer(
const MediaDescriptionOptions& media_description_options,
const MediaSessionOptions& session_options,
const ContentInfo* current_content,
const SessionDescription* current_description,
const RtpHeaderExtensions& video_rtp_extensions,
const VideoCodecs& video_codecs,
StreamParamsVec* current_streams,
SessionDescription* desc) const {
cricket::SecurePolicy sdes_policy =
IsDtlsActive(current_content, current_description) ? cricket::SEC_DISABLED
: secure();
std::unique_ptr<VideoContentDescription> video(new VideoContentDescription());
std::vector<std::string> crypto_suites;
GetSupportedVideoSdesCryptoSuiteNames(session_options.crypto_options,
&crypto_suites);
VideoCodecs filtered_codecs;
// Add the codecs from current content if exists.
if (current_content) {
RTC_CHECK(IsMediaContentOfType(current_content, MEDIA_TYPE_VIDEO));
const VideoContentDescription* vcd =
static_cast<const VideoContentDescription*>(
current_content->description);
for (const VideoCodec& codec : vcd->codecs()) {
if (FindMatchingCodec<VideoCodec>(vcd->codecs(), video_codecs, codec,
nullptr)) {
filtered_codecs.push_back(codec);
}
}
}
// Add other supported video codecs.
VideoCodec found_codec;
for (const VideoCodec& codec : video_codecs_) {
if (FindMatchingCodec<VideoCodec>(video_codecs_, video_codecs, codec,
&found_codec) &&
!FindMatchingCodec<VideoCodec>(video_codecs_, filtered_codecs, codec,
nullptr)) {
// Use the |found_codec| from |video_codecs| because it has the correctly
// mapped payload type.
filtered_codecs.push_back(found_codec);
}
}
if (!CreateMediaContentOffer(
media_description_options.sender_options, session_options,
filtered_codecs, sdes_policy, GetCryptos(current_content),
crypto_suites, video_rtp_extensions, current_streams, video.get())) {
return false;
}
video->set_bandwidth(kAutoBandwidth);
bool secure_transport = (transport_desc_factory_->secure() != SEC_DISABLED);
SetMediaProtocol(secure_transport, video.get());
video->set_direction(
media_description_options.direction.ToMediaContentDirection());
desc->AddContent(media_description_options.mid, NS_JINGLE_RTP,
media_description_options.stopped, video.release());
if (!AddTransportOffer(media_description_options.mid,
media_description_options.transport_options,
current_description, desc)) {
return false;
}
return true;
}
bool MediaSessionDescriptionFactory::AddDataContentForOffer(
const MediaDescriptionOptions& media_description_options,
const MediaSessionOptions& session_options,
const ContentInfo* current_content,
const SessionDescription* current_description,
const DataCodecs& data_codecs,
StreamParamsVec* current_streams,
SessionDescription* desc) const {
bool secure_transport = (transport_desc_factory_->secure() != SEC_DISABLED);
std::unique_ptr<DataContentDescription> data(new DataContentDescription());
bool is_sctp = (session_options.data_channel_type == DCT_SCTP);
// If the DataChannel type is not specified, use the DataChannel type in
// the current description.
if (session_options.data_channel_type == DCT_NONE && current_content) {
RTC_CHECK(IsMediaContentOfType(current_content, MEDIA_TYPE_DATA));
is_sctp = (static_cast<const DataContentDescription*>(
current_content->description)
->protocol() == kMediaProtocolSctp);
}
cricket::SecurePolicy sdes_policy =
IsDtlsActive(current_content, current_description) ? cricket::SEC_DISABLED
: secure();
std::vector<std::string> crypto_suites;
if (is_sctp) {
// SDES doesn't make sense for SCTP, so we disable it, and we only
// get SDES crypto suites for RTP-based data channels.
sdes_policy = cricket::SEC_DISABLED;
// Unlike SetMediaProtocol below, we need to set the protocol
// before we call CreateMediaContentOffer. Otherwise,
// CreateMediaContentOffer won't know this is SCTP and will
// generate SSRCs rather than SIDs.
// TODO(deadbeef): Offer kMediaProtocolUdpDtlsSctp (or TcpDtlsSctp), once
// it's safe to do so. Older versions of webrtc would reject these
// protocols; see https://bugs.chromium.org/p/webrtc/issues/detail?id=7706.
data->set_protocol(
secure_transport ? kMediaProtocolDtlsSctp : kMediaProtocolSctp);
} else {
GetSupportedDataSdesCryptoSuiteNames(session_options.crypto_options,
&crypto_suites);
}
// Even SCTP uses a "codec".
if (!CreateMediaContentOffer(
media_description_options.sender_options, session_options,
data_codecs, sdes_policy, GetCryptos(current_content), crypto_suites,
RtpHeaderExtensions(), current_streams, data.get())) {
return false;
}
if (is_sctp) {
desc->AddContent(media_description_options.mid, NS_JINGLE_DRAFT_SCTP,
data.release());
} else {
data->set_bandwidth(kDataMaxBandwidth);
SetMediaProtocol(secure_transport, data.get());
desc->AddContent(media_description_options.mid, NS_JINGLE_RTP,
media_description_options.stopped, data.release());
}
if (!AddTransportOffer(media_description_options.mid,
media_description_options.transport_options,
current_description, desc)) {
return false;
}
return true;
}
// |audio_codecs| = set of all possible codecs that can be used, with correct
// payload type mappings
//
// |supported_audio_codecs| = set of codecs that are supported for the direction
// of this m= section
//
// acd->codecs() = set of previously negotiated codecs for this m= section
//
// The payload types should come from audio_codecs, but the order should come
// from acd->codecs() and then supported_codecs, to ensure that re-offers don't
// change existing codec priority, and that new codecs are added with the right
// priority.
bool MediaSessionDescriptionFactory::AddAudioContentForAnswer(
const MediaDescriptionOptions& media_description_options,
const MediaSessionOptions& session_options,
const ContentInfo* offer_content,
const SessionDescription* offer_description,
const ContentInfo* current_content,
const SessionDescription* current_description,
const TransportInfo* bundle_transport,
const AudioCodecs& audio_codecs,
StreamParamsVec* current_streams,
SessionDescription* answer) const {
RTC_CHECK(IsMediaContentOfType(offer_content, MEDIA_TYPE_AUDIO));
const AudioContentDescription* offer_audio_description =
static_cast<const AudioContentDescription*>(offer_content->description);
std::unique_ptr<TransportDescription> audio_transport(
CreateTransportAnswer(media_description_options.mid, offer_description,
media_description_options.transport_options,
current_description, bundle_transport != nullptr));
if (!audio_transport) {
return false;
}
// Pick codecs based on the requested communications direction in the offer
// and the selected direction in the answer.
// Note these will be filtered one final time in CreateMediaContentAnswer.
auto wants_rtd = media_description_options.direction;
auto offer_rtd = RtpTransceiverDirection::FromMediaContentDirection(
offer_audio_description->direction());
auto answer_rtd = NegotiateRtpTransceiverDirection(offer_rtd, wants_rtd);
AudioCodecs supported_audio_codecs =
GetAudioCodecsForAnswer(offer_rtd, answer_rtd);
AudioCodecs filtered_codecs;
// Add the codecs from current content if exists.
if (current_content) {
RTC_CHECK(IsMediaContentOfType(current_content, MEDIA_TYPE_AUDIO));
const AudioContentDescription* acd =
static_cast<const AudioContentDescription*>(
current_content->description);
for (const AudioCodec& codec : acd->codecs()) {
if (FindMatchingCodec<AudioCodec>(acd->codecs(), audio_codecs, codec,
nullptr)) {
filtered_codecs.push_back(codec);
}
}
}
// Add other supported audio codecs.
AudioCodec found_codec;
for (const AudioCodec& codec : supported_audio_codecs) {
if (FindMatchingCodec<AudioCodec>(supported_audio_codecs, audio_codecs,
codec, &found_codec) &&
!FindMatchingCodec<AudioCodec>(supported_audio_codecs, filtered_codecs,
codec, nullptr)) {
// Use the |found_codec| from |audio_codecs| because it has the correctly
// mapped payload type.
filtered_codecs.push_back(found_codec);
}
}
bool bundle_enabled = offer_description->HasGroup(GROUP_TYPE_BUNDLE) &&
session_options.bundle_enabled;
std::unique_ptr<AudioContentDescription> audio_answer(
new AudioContentDescription());
// Do not require or create SDES cryptos if DTLS is used.
cricket::SecurePolicy sdes_policy =
audio_transport->secure() ? cricket::SEC_DISABLED : secure();
if (!CreateMediaContentAnswer(
offer_audio_description, media_description_options, session_options,
filtered_codecs, sdes_policy, GetCryptos(current_content),
audio_rtp_extensions_, enable_encrypted_rtp_header_extensions_,
current_streams, bundle_enabled, audio_answer.get())) {
return false; // Fails the session setup.
}
bool secure = bundle_transport ? bundle_transport->description.secure()
: audio_transport->secure();
bool rejected = media_description_options.stopped ||
offer_content->rejected ||
!IsMediaProtocolSupported(MEDIA_TYPE_AUDIO,
audio_answer->protocol(), secure);
if (!rejected) {
AddTransportAnswer(media_description_options.mid, *(audio_transport.get()),
answer);
} else {
LOG(LS_INFO) << "Audio m= section '" << media_description_options.mid
<< "' being rejected in answer.";
}
answer->AddContent(media_description_options.mid, offer_content->type,
rejected, audio_answer.release());
return true;
}
bool MediaSessionDescriptionFactory::AddVideoContentForAnswer(
const MediaDescriptionOptions& media_description_options,
const MediaSessionOptions& session_options,
const ContentInfo* offer_content,
const SessionDescription* offer_description,
const ContentInfo* current_content,
const SessionDescription* current_description,
const TransportInfo* bundle_transport,
const VideoCodecs& video_codecs,
StreamParamsVec* current_streams,
SessionDescription* answer) const {
RTC_CHECK(IsMediaContentOfType(offer_content, MEDIA_TYPE_VIDEO));
const VideoContentDescription* offer_video_description =
static_cast<const VideoContentDescription*>(offer_content->description);
std::unique_ptr<TransportDescription> video_transport(
CreateTransportAnswer(media_description_options.mid, offer_description,
media_description_options.transport_options,
current_description, bundle_transport != nullptr));
if (!video_transport) {
return false;
}
VideoCodecs filtered_codecs;
// Add the codecs from current content if exists.
if (current_content) {
RTC_CHECK(IsMediaContentOfType(current_content, MEDIA_TYPE_VIDEO));
const VideoContentDescription* vcd =
static_cast<const VideoContentDescription*>(
current_content->description);
for (const VideoCodec& codec : vcd->codecs()) {
if (FindMatchingCodec<VideoCodec>(vcd->codecs(), video_codecs, codec,
nullptr)) {
filtered_codecs.push_back(codec);
}
}
}
// Add other supported video codecs.
VideoCodec found_codec;
for (const VideoCodec& codec : video_codecs_) {
if (FindMatchingCodec<VideoCodec>(video_codecs_, video_codecs, codec,
&found_codec) &&
!FindMatchingCodec<VideoCodec>(video_codecs_, filtered_codecs, codec,
nullptr)) {
// Use the |found_codec| from |video_codecs| because it has the correctly
// mapped payload type.
filtered_codecs.push_back(found_codec);
}
}
bool bundle_enabled = offer_description->HasGroup(GROUP_TYPE_BUNDLE) &&
session_options.bundle_enabled;
std::unique_ptr<VideoContentDescription> video_answer(
new VideoContentDescription());
// Do not require or create SDES cryptos if DTLS is used.
cricket::SecurePolicy sdes_policy =
video_transport->secure() ? cricket::SEC_DISABLED : secure();
if (!CreateMediaContentAnswer(
offer_video_description, media_description_options, session_options,
filtered_codecs, sdes_policy, GetCryptos(current_content),
video_rtp_extensions_, enable_encrypted_rtp_header_extensions_,
current_streams, bundle_enabled, video_answer.get())) {
return false; // Failed the sessin setup.
}
bool secure = bundle_transport ? bundle_transport->description.secure()
: video_transport->secure();
bool rejected = media_description_options.stopped ||
offer_content->rejected ||
!IsMediaProtocolSupported(MEDIA_TYPE_VIDEO,
video_answer->protocol(), secure);
if (!rejected) {
if (!AddTransportAnswer(media_description_options.mid,
*(video_transport.get()), answer)) {
return false;
}
video_answer->set_bandwidth(kAutoBandwidth);
} else {
LOG(LS_INFO) << "Video m= section '" << media_description_options.mid
<< "' being rejected in answer.";
}
answer->AddContent(media_description_options.mid, offer_content->type,
rejected, video_answer.release());
return true;
}
bool MediaSessionDescriptionFactory::AddDataContentForAnswer(
const MediaDescriptionOptions& media_description_options,
const MediaSessionOptions& session_options,
const ContentInfo* offer_content,
const SessionDescription* offer_description,
const ContentInfo* current_content,
const SessionDescription* current_description,
const TransportInfo* bundle_transport,
const DataCodecs& data_codecs,
StreamParamsVec* current_streams,
SessionDescription* answer) const {
std::unique_ptr<TransportDescription> data_transport(
CreateTransportAnswer(media_description_options.mid, offer_description,
media_description_options.transport_options,
current_description, bundle_transport != nullptr));
if (!data_transport) {
return false;
}
std::unique_ptr<DataContentDescription> data_answer(
new DataContentDescription());
// Do not require or create SDES cryptos if DTLS is used.
cricket::SecurePolicy sdes_policy =
data_transport->secure() ? cricket::SEC_DISABLED : secure();
bool bundle_enabled = offer_description->HasGroup(GROUP_TYPE_BUNDLE) &&
session_options.bundle_enabled;
RTC_CHECK(IsMediaContentOfType(offer_content, MEDIA_TYPE_DATA));
const DataContentDescription* offer_data_description =
static_cast<const DataContentDescription*>(offer_content->description);
if (!CreateMediaContentAnswer(
offer_data_description, media_description_options, session_options,
data_codecs, sdes_policy, GetCryptos(current_content),
RtpHeaderExtensions(), enable_encrypted_rtp_header_extensions_,
current_streams, bundle_enabled, data_answer.get())) {
return false; // Fails the session setup.
}
// Respond with sctpmap if the offer uses sctpmap.
bool offer_uses_sctpmap = offer_data_description->use_sctpmap();
data_answer->set_use_sctpmap(offer_uses_sctpmap);
bool secure = bundle_transport ? bundle_transport->description.secure()
: data_transport->secure();
bool rejected = session_options.data_channel_type == DCT_NONE ||
media_description_options.stopped ||
offer_content->rejected ||
!IsMediaProtocolSupported(MEDIA_TYPE_DATA,
data_answer->protocol(), secure);
if (!rejected) {
data_answer->set_bandwidth(kDataMaxBandwidth);
if (!AddTransportAnswer(media_description_options.mid,
*(data_transport.get()), answer)) {
return false;
}
} else {
// RFC 3264
// The answer MUST contain the same number of m-lines as the offer.
LOG(LS_INFO) << "Data is not supported in the answer.";
}
answer->AddContent(media_description_options.mid, offer_content->type,
rejected, data_answer.release());
return true;
}
void MediaSessionDescriptionFactory::ComputeAudioCodecsIntersectionAndUnion() {
audio_sendrecv_codecs_.clear();
all_audio_codecs_.clear();
// Compute the audio codecs union.
for (const AudioCodec& send : audio_send_codecs_) {
all_audio_codecs_.push_back(send);
if (!FindMatchingCodec<AudioCodec>(audio_send_codecs_, audio_recv_codecs_,
send, nullptr)) {
// It doesn't make sense to have an RTX codec we support sending but not
// receiving.
RTC_DCHECK(!IsRtxCodec(send));
}
}
for (const AudioCodec& recv : audio_recv_codecs_) {
if (!FindMatchingCodec<AudioCodec>(audio_recv_codecs_, audio_send_codecs_,
recv, nullptr)) {
all_audio_codecs_.push_back(recv);
}
}
// Use NegotiateCodecs to merge our codec lists, since the operation is
// essentially the same. Put send_codecs as the offered_codecs, which is the
// order we'd like to follow. The reasoning is that encoding is usually more
// expensive than decoding, and prioritizing a codec in the send list probably
// means it's a codec we can handle efficiently.
NegotiateCodecs(audio_recv_codecs_, audio_send_codecs_,
&audio_sendrecv_codecs_);
}
bool IsMediaContent(const ContentInfo* content) {
return (content &&
(content->type == NS_JINGLE_RTP ||
content->type == NS_JINGLE_DRAFT_SCTP));
}
bool IsAudioContent(const ContentInfo* content) {
return IsMediaContentOfType(content, MEDIA_TYPE_AUDIO);
}
bool IsVideoContent(const ContentInfo* content) {
return IsMediaContentOfType(content, MEDIA_TYPE_VIDEO);
}
bool IsDataContent(const ContentInfo* content) {
return IsMediaContentOfType(content, MEDIA_TYPE_DATA);
}
const ContentInfo* GetFirstMediaContent(const ContentInfos& contents,
MediaType media_type) {
for (const ContentInfo& content : contents) {
if (IsMediaContentOfType(&content, media_type)) {
return &content;
}
}
return nullptr;
}
const ContentInfo* GetFirstAudioContent(const ContentInfos& contents) {
return GetFirstMediaContent(contents, MEDIA_TYPE_AUDIO);
}
const ContentInfo* GetFirstVideoContent(const ContentInfos& contents) {
return GetFirstMediaContent(contents, MEDIA_TYPE_VIDEO);
}
const ContentInfo* GetFirstDataContent(const ContentInfos& contents) {
return GetFirstMediaContent(contents, MEDIA_TYPE_DATA);
}
static const ContentInfo* GetFirstMediaContent(const SessionDescription* sdesc,
MediaType media_type) {
if (sdesc == nullptr) {
return nullptr;
}
return GetFirstMediaContent(sdesc->contents(), media_type);
}
const ContentInfo* GetFirstAudioContent(const SessionDescription* sdesc) {
return GetFirstMediaContent(sdesc, MEDIA_TYPE_AUDIO);
}
const ContentInfo* GetFirstVideoContent(const SessionDescription* sdesc) {
return GetFirstMediaContent(sdesc, MEDIA_TYPE_VIDEO);
}
const ContentInfo* GetFirstDataContent(const SessionDescription* sdesc) {
return GetFirstMediaContent(sdesc, MEDIA_TYPE_DATA);
}
const MediaContentDescription* GetFirstMediaContentDescription(
const SessionDescription* sdesc, MediaType media_type) {
const ContentInfo* content = GetFirstMediaContent(sdesc, media_type);
const ContentDescription* description = content ? content->description : NULL;
return static_cast<const MediaContentDescription*>(description);
}
const AudioContentDescription* GetFirstAudioContentDescription(
const SessionDescription* sdesc) {
return static_cast<const AudioContentDescription*>(
GetFirstMediaContentDescription(sdesc, MEDIA_TYPE_AUDIO));
}
const VideoContentDescription* GetFirstVideoContentDescription(
const SessionDescription* sdesc) {
return static_cast<const VideoContentDescription*>(
GetFirstMediaContentDescription(sdesc, MEDIA_TYPE_VIDEO));
}
const DataContentDescription* GetFirstDataContentDescription(
const SessionDescription* sdesc) {
return static_cast<const DataContentDescription*>(
GetFirstMediaContentDescription(sdesc, MEDIA_TYPE_DATA));
}
//
// Non-const versions of the above functions.
//
ContentInfo* GetFirstMediaContent(ContentInfos& contents,
MediaType media_type) {
for (ContentInfo& content : contents) {
if (IsMediaContentOfType(&content, media_type)) {
return &content;
}
}
return nullptr;
}
ContentInfo* GetFirstAudioContent(ContentInfos& contents) {
return GetFirstMediaContent(contents, MEDIA_TYPE_AUDIO);
}
ContentInfo* GetFirstVideoContent(ContentInfos& contents) {
return GetFirstMediaContent(contents, MEDIA_TYPE_VIDEO);
}
ContentInfo* GetFirstDataContent(ContentInfos& contents) {
return GetFirstMediaContent(contents, MEDIA_TYPE_DATA);
}
static ContentInfo* GetFirstMediaContent(SessionDescription* sdesc,
MediaType media_type) {
if (sdesc == nullptr) {
return nullptr;
}
return GetFirstMediaContent(sdesc->contents(), media_type);
}
ContentInfo* GetFirstAudioContent(SessionDescription* sdesc) {
return GetFirstMediaContent(sdesc, MEDIA_TYPE_AUDIO);
}
ContentInfo* GetFirstVideoContent(SessionDescription* sdesc) {
return GetFirstMediaContent(sdesc, MEDIA_TYPE_VIDEO);
}
ContentInfo* GetFirstDataContent(SessionDescription* sdesc) {
return GetFirstMediaContent(sdesc, MEDIA_TYPE_DATA);
}
MediaContentDescription* GetFirstMediaContentDescription(
SessionDescription* sdesc,
MediaType media_type) {
ContentInfo* content = GetFirstMediaContent(sdesc, media_type);
ContentDescription* description = content ? content->description : NULL;
return static_cast<MediaContentDescription*>(description);
}
AudioContentDescription* GetFirstAudioContentDescription(
SessionDescription* sdesc) {
return static_cast<AudioContentDescription*>(
GetFirstMediaContentDescription(sdesc, MEDIA_TYPE_AUDIO));
}
VideoContentDescription* GetFirstVideoContentDescription(
SessionDescription* sdesc) {
return static_cast<VideoContentDescription*>(
GetFirstMediaContentDescription(sdesc, MEDIA_TYPE_VIDEO));
}
DataContentDescription* GetFirstDataContentDescription(
SessionDescription* sdesc) {
return static_cast<DataContentDescription*>(
GetFirstMediaContentDescription(sdesc, MEDIA_TYPE_DATA));
}
} // namespace cricket