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webrtc/pc/mediasession.cc
Artem Titov a76af0ca2e Move base64.h to the proper location. 
Move base64.h to the proper location and put redirect header into the
old place to be able to switch downstream users on new location.

Bug: webrtc:8366
Change-Id: I5191fe631d32178d2efd1315ca9abd4250102291
Reviewed-on: https://webrtc-review.googlesource.com/88223
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Henrik Andreassson <henrika@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24069}
2018-07-23 15:40:36 +00:00

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/*
* 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 "absl/types/optional.h"
#include "api/cryptoparams.h"
#include "common_types.h" // NOLINT(build/include)
#include "media/base/h264_profile_level_id.h"
#include "media/base/mediaconstants.h"
#include "p2p/base/p2pconstants.h"
#include "pc/channelmanager.h"
#include "pc/rtpmediautils.h"
#include "pc/srtpfilter.h"
#include "rtc_base/checks.h"
#include "rtc_base/helpers.h"
#include "rtc_base/logging.h"
#include "rtc_base/stringutils.h"
#include "rtc_base/third_party/base64/base64.h"
namespace {
using webrtc::RtpTransceiverDirection;
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);
}
static RtpTransceiverDirection NegotiateRtpTransceiverDirection(
RtpTransceiverDirection offer,
RtpTransceiverDirection wants) {
bool offer_send = webrtc::RtpTransceiverDirectionHasSend(offer);
bool offer_recv = webrtc::RtpTransceiverDirectionHasRecv(offer);
bool wants_send = webrtc::RtpTransceiverDirectionHasSend(wants);
bool wants_recv = webrtc::RtpTransceiverDirectionHasRecv(wants);
return webrtc::RtpTransceiverDirectionFromSendRecv(offer_recv && wants_send,
offer_send && wants_recv);
}
static bool IsMediaContentOfType(const ContentInfo* content,
MediaType media_type) {
if (!content || !content->media_description()) {
return false;
}
return content->media_description()->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 || !content->media_description()) {
return nullptr;
}
return &content->media_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 (if enabled) 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);
}
if (crypto_options.enable_aes128_sha1_32_crypto_cipher) {
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 (if enabled) 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 && crypto_options.enable_aes128_sha1_32_crypto_cipher)) {
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) {
RTC_DCHECK(stream_params);
if (!sdesc) {
return;
}
for (const ContentInfo& content : sdesc->contents()) {
if (!content.media_description()) {
continue;
}
for (const StreamParams& params : content.media_description()->streams()) {
stream_params->push_back(params);
}
}
}
// 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();
RTC_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]);
}
}
// 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]);
} else if (!ssrcs.empty()) {
RTC_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;
stream_param.set_stream_ids(sender.stream_ids);
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.
param->set_stream_ids(sender.stream_ids);
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 (!content || !content->media_description()) {
return false;
}
*cryptos = content->media_description()->cryptos();
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(),
// Returns true if the |crypto|'s cipher_suite is not
// found in |filter|.
[&filter](const CryptoParams& crypto) {
for (const CryptoParams& entry : filter) {
if (entry.cipher_suite == crypto.cipher_suite)
return false;
}
return true;
}),
target_cryptos->end());
}
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 (content && content->media_description()) {
is_rtp = IsRtpProtocol(content->media_description()->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 = content->media_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_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)) {
RTC_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)) {
RTC_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)) {
RTC_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) {
RTC_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)) {
RTC_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.
}
answer->set_direction(NegotiateRtpTransceiverDirection(
offer->direction(), media_description_options.direction));
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();
}
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(session_options, 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|.
size_t msection_index = 0;
for (const MediaDescriptionOptions& media_description_options :
session_options.media_description_options) {
const ContentInfo* current_content = nullptr;
if (current_description &&
msection_index < current_description->contents().size()) {
current_content = &current_description->contents()[msection_index];
// Media type must match unless this media section is being recycled.
RTC_DCHECK(current_content->rejected ||
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())) {
RTC_LOG(LS_ERROR)
<< "CreateOffer failed to UpdateTransportInfoForBundle.";
return nullptr;
}
if (!UpdateCryptoParamsForBundle(offer_bundle, offer.get())) {
RTC_LOG(LS_ERROR) << "CreateOffer failed to UpdateCryptoParamsForBundle.";
return nullptr;
}
}
// The following determines how to signal MSIDs to ensure compatibility with
// older endpoints (in particular, older Plan B endpoints).
if (session_options.is_unified_plan) {
// Be conservative and signal using both a=msid and a=ssrc lines. Unified
// Plan answerers will look at a=msid and Plan B answerers will look at the
// a=ssrc MSID line.
offer->set_msid_signaling(cricket::kMsidSignalingMediaSection |
cricket::kMsidSignalingSsrcAttribute);
} else {
// Plan B always signals MSID using a=ssrc lines.
offer->set_msid_signaling(cricket::kMsidSignalingSsrcAttribute);
}
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|.
size_t 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 < 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)));
}
}
// If a BUNDLE group was offered, put a BUNDLE group in the answer even if
// it's 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 (!UpdateCryptoParamsForBundle(answer_bundle, answer.get())) {
RTC_LOG(LS_ERROR)
<< "CreateAnswer failed to UpdateCryptoParamsForBundle.";
return NULL;
}
}
// The following determines how to signal MSIDs to ensure compatibility with
// older endpoints (in particular, older Plan B endpoints).
if (session_options.is_unified_plan) {
// Unified Plan needs to look at what the offer included to find the most
// compatible answer.
if (offer->msid_signaling() == 0) {
// We end up here in one of three cases:
// 1. An empty offer. We'll reply with an empty answer so it doesn't
// matter what we pick here.
// 2. A data channel only offer. We won't add any MSIDs to the answer so
// it also doesn't matter what we pick here.
// 3. Media that's either sendonly or inactive from the remote endpoint.
// We don't have any information to say whether the endpoint is Plan B
// or Unified Plan, so be conservative and send both.
answer->set_msid_signaling(cricket::kMsidSignalingMediaSection |
cricket::kMsidSignalingSsrcAttribute);
} else if (offer->msid_signaling() ==
(cricket::kMsidSignalingMediaSection |
cricket::kMsidSignalingSsrcAttribute)) {
// If both a=msid and a=ssrc MSID signaling methods were used, we're
// probably talking to a Unified Plan endpoint so respond with just
// a=msid.
answer->set_msid_signaling(cricket::kMsidSignalingMediaSection);
} else {
// Otherwise, it's clear which method the offerer is using so repeat that
// back to them.
answer->set_msid_signaling(offer->msid_signaling());
}
} else {
// Plan B always signals MSID using a=ssrc lines.
answer->set_msid_signaling(cricket::kMsidSignalingSsrcAttribute);
}
return answer.release();
}
const AudioCodecs& MediaSessionDescriptionFactory::GetAudioCodecsForOffer(
const RtpTransceiverDirection& direction) const {
switch (direction) {
// If stream is inactive - generate list as if sendrecv.
case RtpTransceiverDirection::kSendRecv:
case RtpTransceiverDirection::kInactive:
return audio_sendrecv_codecs_;
case RtpTransceiverDirection::kSendOnly:
return audio_send_codecs_;
case RtpTransceiverDirection::kRecvOnly:
return audio_recv_codecs_;
}
RTC_NOTREACHED();
return audio_sendrecv_codecs_;
}
const AudioCodecs& MediaSessionDescriptionFactory::GetAudioCodecsForAnswer(
const RtpTransceiverDirection& offer,
const RtpTransceiverDirection& answer) const {
switch (answer) {
// For inactive and sendrecv answers, generate lists as if we were to accept
// the offer's direction. See RFC 3264 Section 6.1.
case RtpTransceiverDirection::kSendRecv:
case RtpTransceiverDirection::kInactive:
return GetAudioCodecsForOffer(
webrtc::RtpTransceiverDirectionReversed(offer));
case RtpTransceiverDirection::kSendOnly:
return audio_send_codecs_;
case RtpTransceiverDirection::kRecvOnly:
return audio_recv_codecs_;
}
RTC_NOTREACHED();
return audio_sendrecv_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 =
content.media_description()->as_audio();
MergeCodecs<AudioCodec>(audio->codecs(), audio_codecs, used_pltypes);
} else if (IsMediaContentOfType(&content, MEDIA_TYPE_VIDEO)) {
const VideoContentDescription* video =
content.media_description()->as_video();
MergeCodecs<VideoCodec>(video->codecs(), video_codecs, used_pltypes);
} else if (IsMediaContentOfType(&content, MEDIA_TYPE_DATA)) {
const DataContentDescription* data =
content.media_description()->as_data();
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 =
content.media_description()->as_audio();
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 =
content.media_description()->as_video();
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 =
content.media_description()->as_data();
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 MediaSessionOptions& session_options,
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 =
content.media_description()->as_audio();
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 =
content.media_description()->as_video();
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(session_options.is_unified_plan),
offer_audio_extensions, &all_regular_extensions,
&all_encrypted_extensions, &used_ids);
MergeRtpHdrExts(video_rtp_header_extensions(session_options.is_unified_plan),
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) {
RTC_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))) {
RTC_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 it exists and is not being recycled.
if (current_content && !current_content->rejected) {
RTC_CHECK(IsMediaContentOfType(current_content, MEDIA_TYPE_AUDIO));
const AudioContentDescription* acd =
current_content->media_description()->as_audio();
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;
}
bool secure_transport = (transport_desc_factory_->secure() != SEC_DISABLED);
SetMediaProtocol(secure_transport, audio.get());
audio->set_direction(media_description_options.direction);
desc->AddContent(media_description_options.mid, MediaProtocolType::kRtp,
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 it exists and is not being recycled.
if (current_content && !current_content->rejected) {
RTC_CHECK(IsMediaContentOfType(current_content, MEDIA_TYPE_VIDEO));
const VideoContentDescription* vcd =
current_content->media_description()->as_video();
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);
desc->AddContent(media_description_options.mid, MediaProtocolType::kRtp,
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 = (current_content->media_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, MediaProtocolType::kSctp,
data.release());
} else {
data->set_bandwidth(kDataMaxBandwidth);
SetMediaProtocol(secure_transport, data.get());
desc->AddContent(media_description_options.mid, MediaProtocolType::kRtp,
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 =
offer_content->media_description()->as_audio();
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 = 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 it exists and is not being recycled.
if (current_content && !current_content->rejected) {
RTC_CHECK(IsMediaContentOfType(current_content, MEDIA_TYPE_AUDIO));
const AudioContentDescription* acd =
current_content->media_description()->as_audio();
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.
for (const AudioCodec& codec : supported_audio_codecs) {
if (FindMatchingCodec<AudioCodec>(supported_audio_codecs, audio_codecs,
codec, nullptr) &&
!FindMatchingCodec<AudioCodec>(supported_audio_codecs, filtered_codecs,
codec, nullptr)) {
// We should use the local codec with local parameters and the codec id
// would be correctly mapped in |NegotiateCodecs|.
filtered_codecs.push_back(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_header_extensions(session_options.is_unified_plan),
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 (!AddTransportAnswer(media_description_options.mid,
*(audio_transport.get()), answer)) {
return false;
}
if (rejected) {
RTC_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 =
offer_content->media_description()->as_video();
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 it exists and is not being recycled.
if (current_content && !current_content->rejected) {
RTC_CHECK(IsMediaContentOfType(current_content, MEDIA_TYPE_VIDEO));
const VideoContentDescription* vcd =
current_content->media_description()->as_video();
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.
for (const VideoCodec& codec : video_codecs_) {
if (FindMatchingCodec<VideoCodec>(video_codecs_, video_codecs, codec,
nullptr) &&
!FindMatchingCodec<VideoCodec>(video_codecs_, filtered_codecs, codec,
nullptr)) {
// We should use the local codec with local parameters and the codec id
// would be correctly mapped in |NegotiateCodecs|.
filtered_codecs.push_back(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_header_extensions(session_options.is_unified_plan),
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 (!AddTransportAnswer(media_description_options.mid,
*(video_transport.get()), answer)) {
return false;
}
if (!rejected) {
video_answer->set_bandwidth(kAutoBandwidth);
} else {
RTC_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 =
offer_content->media_description()->as_data();
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 (!AddTransportAnswer(media_description_options.mid,
*(data_transport.get()), answer)) {
return false;
}
if (!rejected) {
data_answer->set_bandwidth(kDataMaxBandwidth);
} else {
// RFC 3264
// The answer MUST contain the same number of m-lines as the offer.
RTC_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 == MediaProtocolType::kRtp ||
content->type == MediaProtocolType::kSctp));
}
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);
}
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);
return (content ? content->media_description() : nullptr);
}
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);
}
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);
return (content ? content->media_description() : nullptr);
}
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
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