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/*
* Copyright 2013 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/webrtcsessiondescriptionfactory.h"
#include <algorithm>
#include <string>
#include <utility>
#include <vector>
#include "api/jsep.h"
#include "api/jsepsessiondescription.h"
#include "api/mediaconstraintsinterface.h"
#include "rtc_base/checks.h"
#include "rtc_base/ptr_util.h"
#include "rtc_base/sslidentity.h"
using cricket::MediaSessionOptions;
namespace webrtc {
namespace {
static const char kFailedDueToIdentityFailed[] =
" failed because DTLS identity request failed";
static const char kFailedDueToSessionShutdown[] =
" failed because the session was shut down";
static const uint64_t kInitSessionVersion = 2;
static bool CompareSenderOptions(const cricket::SenderOptions& sender1,
const cricket::SenderOptions& sender2) {
return sender1.track_id < sender2.track_id;
}
static bool SameId(const cricket::SenderOptions& sender1,
const cricket::SenderOptions& sender2) {
return sender1.track_id == sender2.track_id;
}
// Check that each sender has a unique ID.
static bool ValidMediaSessionOptions(
const cricket::MediaSessionOptions& session_options) {
std::vector<cricket::SenderOptions> sorted_senders;
for (const cricket::MediaDescriptionOptions& media_description_options :
session_options.media_description_options) {
sorted_senders.insert(sorted_senders.end(),
media_description_options.sender_options.begin(),
media_description_options.sender_options.end());
}
std::sort(sorted_senders.begin(), sorted_senders.end(), CompareSenderOptions);
std::vector<cricket::SenderOptions>::iterator it =
std::adjacent_find(sorted_senders.begin(), sorted_senders.end(), SameId);
return it == sorted_senders.end();
}
enum {
MSG_CREATE_SESSIONDESCRIPTION_SUCCESS,
MSG_CREATE_SESSIONDESCRIPTION_FAILED,
MSG_USE_CONSTRUCTOR_CERTIFICATE
};
struct CreateSessionDescriptionMsg : public rtc::MessageData {
explicit CreateSessionDescriptionMsg(
webrtc::CreateSessionDescriptionObserver* observer)
: observer(observer) {
}
rtc::scoped_refptr<webrtc::CreateSessionDescriptionObserver> observer;
std::string error;
std::unique_ptr<webrtc::SessionDescriptionInterface> description;
};
} // namespace
void WebRtcCertificateGeneratorCallback::OnFailure() {
SignalRequestFailed();
}
void WebRtcCertificateGeneratorCallback::OnSuccess(
const rtc::scoped_refptr<rtc::RTCCertificate>& certificate) {
SignalCertificateReady(certificate);
}
// static
void WebRtcSessionDescriptionFactory::CopyCandidatesFromSessionDescription(
const SessionDescriptionInterface* source_desc,
const std::string& content_name,
SessionDescriptionInterface* dest_desc) {
if (!source_desc) {
return;
}
const cricket::ContentInfos& contents =
source_desc->description()->contents();
const cricket::ContentInfo* cinfo =
source_desc->description()->GetContentByName(content_name);
if (!cinfo) {
return;
}
size_t mediasection_index = static_cast<int>(cinfo - &contents[0]);
const IceCandidateCollection* source_candidates =
source_desc->candidates(mediasection_index);
const IceCandidateCollection* dest_candidates =
dest_desc->candidates(mediasection_index);
if (!source_candidates || !dest_candidates) {
return;
}
for (size_t n = 0; n < source_candidates->count(); ++n) {
const IceCandidateInterface* new_candidate = source_candidates->at(n);
if (!dest_candidates->HasCandidate(new_candidate)) {
dest_desc->AddCandidate(source_candidates->at(n));
}
}
}
// Private constructor called by other constructors.
WebRtcSessionDescriptionFactory::WebRtcSessionDescriptionFactory(
rtc::Thread* signaling_thread,
cricket::ChannelManager* channel_manager,
PeerConnectionInternal* pc,
const std::string& session_id,
std::unique_ptr<rtc::RTCCertificateGeneratorInterface> cert_generator,
const rtc::scoped_refptr<rtc::RTCCertificate>& certificate)
: signaling_thread_(signaling_thread),
session_desc_factory_(channel_manager, &transport_desc_factory_),
// RFC 4566 suggested a Network Time Protocol (NTP) format timestamp
// as the session id and session version. To simplify, it should be fine
// to just use a random number as session id and start version from
// |kInitSessionVersion|.
session_version_(kInitSessionVersion),
cert_generator_(std::move(cert_generator)),
pc_(pc),
session_id_(session_id),
certificate_request_state_(CERTIFICATE_NOT_NEEDED) {
RTC_DCHECK(signaling_thread_);
RTC_DCHECK(!(cert_generator_ && certificate));
bool dtls_enabled = cert_generator_ || certificate;
// SRTP-SDES is disabled if DTLS is on.
SetSdesPolicy(dtls_enabled ? cricket::SEC_DISABLED : cricket::SEC_REQUIRED);
if (!dtls_enabled) {
RTC_LOG(LS_VERBOSE) << "DTLS-SRTP disabled.";
return;
}
if (certificate) {
// Use |certificate|.
certificate_request_state_ = CERTIFICATE_WAITING;
RTC_LOG(LS_VERBOSE) << "DTLS-SRTP enabled; has certificate parameter.";
// We already have a certificate but we wait to do |SetIdentity|; if we do
// it in the constructor then the caller has not had a chance to connect to
// |SignalCertificateReady|.
signaling_thread_->Post(
RTC_FROM_HERE, this, MSG_USE_CONSTRUCTOR_CERTIFICATE,
new rtc::ScopedRefMessageData<rtc::RTCCertificate>(certificate));
} else {
// Generate certificate.
certificate_request_state_ = CERTIFICATE_WAITING;
rtc::scoped_refptr<WebRtcCertificateGeneratorCallback> callback(
new rtc::RefCountedObject<WebRtcCertificateGeneratorCallback>());
callback->SignalRequestFailed.connect(
this, &WebRtcSessionDescriptionFactory::OnCertificateRequestFailed);
callback->SignalCertificateReady.connect(
this, &WebRtcSessionDescriptionFactory::SetCertificate);
rtc::KeyParams key_params = rtc::KeyParams();
RTC_LOG(LS_VERBOSE)
<< "DTLS-SRTP enabled; sending DTLS identity request (key type: "
<< key_params.type() << ").";
// Request certificate. This happens asynchronously, so that the caller gets
// a chance to connect to |SignalCertificateReady|.
cert_generator_->GenerateCertificateAsync(key_params, rtc::nullopt,
callback);
}
}
WebRtcSessionDescriptionFactory::~WebRtcSessionDescriptionFactory() {
RTC_DCHECK(signaling_thread_->IsCurrent());
// Fail any requests that were asked for before identity generation completed.
FailPendingRequests(kFailedDueToSessionShutdown);
// Process all pending notifications in the message queue. If we don't do
// this, requests will linger and not know they succeeded or failed.
rtc::MessageList list;
signaling_thread_->Clear(this, rtc::MQID_ANY, &list);
for (auto& msg : list) {
if (msg.message_id != MSG_USE_CONSTRUCTOR_CERTIFICATE) {
OnMessage(&msg);
} else {
// Skip MSG_USE_CONSTRUCTOR_CERTIFICATE because we don't want to trigger
// SetIdentity-related callbacks in the destructor. This can be a problem
// when WebRtcSession listens to the callback but it was the WebRtcSession
// destructor that caused WebRtcSessionDescriptionFactory's destruction.
// The callback is then ignored, leaking memory allocated by OnMessage for
// MSG_USE_CONSTRUCTOR_CERTIFICATE.
delete msg.pdata;
}
}
}
void WebRtcSessionDescriptionFactory::CreateOffer(
CreateSessionDescriptionObserver* observer,
const PeerConnectionInterface::RTCOfferAnswerOptions& options,
const cricket::MediaSessionOptions& session_options) {
std::string error = "CreateOffer";
if (certificate_request_state_ == CERTIFICATE_FAILED) {
error += kFailedDueToIdentityFailed;
RTC_LOG(LS_ERROR) << error;
PostCreateSessionDescriptionFailed(observer, error);
return;
}
if (!ValidMediaSessionOptions(session_options)) {
error += " called with invalid session options";
RTC_LOG(LS_ERROR) << error;
PostCreateSessionDescriptionFailed(observer, error);
return;
}
CreateSessionDescriptionRequest request(
CreateSessionDescriptionRequest::kOffer, observer, session_options);
if (certificate_request_state_ == CERTIFICATE_WAITING) {
create_session_description_requests_.push(request);
} else {
RTC_DCHECK(certificate_request_state_ == CERTIFICATE_SUCCEEDED ||
certificate_request_state_ == CERTIFICATE_NOT_NEEDED);
InternalCreateOffer(request);
}
}
void WebRtcSessionDescriptionFactory::CreateAnswer(
CreateSessionDescriptionObserver* observer,
const cricket::MediaSessionOptions& session_options) {
std::string error = "CreateAnswer";
if (certificate_request_state_ == CERTIFICATE_FAILED) {
error += kFailedDueToIdentityFailed;
RTC_LOG(LS_ERROR) << error;
PostCreateSessionDescriptionFailed(observer, error);
return;
}
if (!pc_->remote_description()) {
error += " can't be called before SetRemoteDescription.";
RTC_LOG(LS_ERROR) << error;
PostCreateSessionDescriptionFailed(observer, error);
return;
}
if (pc_->remote_description()->GetType() != SdpType::kOffer) {
error += " failed because remote_description is not an offer.";
RTC_LOG(LS_ERROR) << error;
PostCreateSessionDescriptionFailed(observer, error);
return;
}
if (!ValidMediaSessionOptions(session_options)) {
error += " called with invalid session options.";
RTC_LOG(LS_ERROR) << error;
PostCreateSessionDescriptionFailed(observer, error);
return;
}
CreateSessionDescriptionRequest request(
CreateSessionDescriptionRequest::kAnswer, observer, session_options);
if (certificate_request_state_ == CERTIFICATE_WAITING) {
create_session_description_requests_.push(request);
} else {
RTC_DCHECK(certificate_request_state_ == CERTIFICATE_SUCCEEDED ||
certificate_request_state_ == CERTIFICATE_NOT_NEEDED);
InternalCreateAnswer(request);
}
}
void WebRtcSessionDescriptionFactory::SetSdesPolicy(
cricket::SecurePolicy secure_policy) {
session_desc_factory_.set_secure(secure_policy);
}
cricket::SecurePolicy WebRtcSessionDescriptionFactory::SdesPolicy() const {
return session_desc_factory_.secure();
}
void WebRtcSessionDescriptionFactory::OnMessage(rtc::Message* msg) {
switch (msg->message_id) {
case MSG_CREATE_SESSIONDESCRIPTION_SUCCESS: {
CreateSessionDescriptionMsg* param =
static_cast<CreateSessionDescriptionMsg*>(msg->pdata);
param->observer->OnSuccess(param->description.release());
delete param;
break;
}
case MSG_CREATE_SESSIONDESCRIPTION_FAILED: {
CreateSessionDescriptionMsg* param =
static_cast<CreateSessionDescriptionMsg*>(msg->pdata);
param->observer->OnFailure(param->error);
delete param;
break;
}
case MSG_USE_CONSTRUCTOR_CERTIFICATE: {
rtc::ScopedRefMessageData<rtc::RTCCertificate>* param =
static_cast<rtc::ScopedRefMessageData<rtc::RTCCertificate>*>(
msg->pdata);
RTC_LOG(LS_INFO) << "Using certificate supplied to the constructor.";
SetCertificate(param->data());
delete param;
break;
}
default:
RTC_NOTREACHED();
break;
}
}
void WebRtcSessionDescriptionFactory::InternalCreateOffer(
CreateSessionDescriptionRequest request) {
if (pc_->local_description()) {
// If the needs-ice-restart flag is set as described by JSEP, we should
// generate an offer with a new ufrag/password to trigger an ICE restart.
for (cricket::MediaDescriptionOptions& options :
request.options.media_description_options) {
if (pc_->NeedsIceRestart(options.mid)) {
options.transport_options.ice_restart = true;
}
}
}
cricket::SessionDescription* desc(session_desc_factory_.CreateOffer(
request.options, pc_->local_description()
? pc_->local_description()->description()
: nullptr));
// RFC 3264
// When issuing an offer that modifies the session,
// the "o=" line of the new SDP MUST be identical to that in the
// previous SDP, except that the version in the origin field MUST
// increment by one from the previous SDP.
// Just increase the version number by one each time when a new offer
// is created regardless if it's identical to the previous one or not.
// The |session_version_| is a uint64_t, the wrap around should not happen.
RTC_DCHECK(session_version_ + 1 > session_version_);
auto offer = rtc::MakeUnique<JsepSessionDescription>(SdpType::kOffer);
if (!offer->Initialize(desc, session_id_,
rtc::ToString(session_version_++))) {
PostCreateSessionDescriptionFailed(request.observer,
"Failed to initialize the offer.");
return;
}
if (pc_->local_description()) {
for (const cricket::MediaDescriptionOptions& options :
request.options.media_description_options) {
if (!options.transport_options.ice_restart) {
CopyCandidatesFromSessionDescription(pc_->local_description(),
options.mid, offer.get());
}
}
}
PostCreateSessionDescriptionSucceeded(request.observer, std::move(offer));
}
void WebRtcSessionDescriptionFactory::InternalCreateAnswer(
CreateSessionDescriptionRequest request) {
if (pc_->remote_description()) {
for (cricket::MediaDescriptionOptions& options :
request.options.media_description_options) {
// According to http://tools.ietf.org/html/rfc5245#section-9.2.1.1
// an answer should also contain new ICE ufrag and password if an offer
// has been received with new ufrag and password.
options.transport_options.ice_restart =
pc_->IceRestartPending(options.mid);
// We should pass the current SSL role to the transport description
// factory, if there is already an existing ongoing session.
rtc::SSLRole ssl_role;
if (pc_->GetSslRole(options.mid, &ssl_role)) {
options.transport_options.prefer_passive_role =
(rtc::SSL_SERVER == ssl_role);
}
}
}
cricket::SessionDescription* desc(session_desc_factory_.CreateAnswer(
pc_->remote_description() ? pc_->remote_description()->description()
: nullptr,
request.options,
pc_->local_description() ? pc_->local_description()->description()
: nullptr));
// RFC 3264
// If the answer is different from the offer in any way (different IP
// addresses, ports, etc.), the origin line MUST be different in the answer.
// In that case, the version number in the "o=" line of the answer is
// unrelated to the version number in the o line of the offer.
// Get a new version number by increasing the |session_version_answer_|.
// The |session_version_| is a uint64_t, the wrap around should not happen.
RTC_DCHECK(session_version_ + 1 > session_version_);
auto answer = rtc::MakeUnique<JsepSessionDescription>(SdpType::kAnswer);
if (!answer->Initialize(desc, session_id_,
rtc::ToString(session_version_++))) {
PostCreateSessionDescriptionFailed(request.observer,
"Failed to initialize the answer.");
return;
}
if (pc_->local_description()) {
// Include all local ICE candidates in the SessionDescription unless
// the remote peer has requested an ICE restart.
for (const cricket::MediaDescriptionOptions& options :
request.options.media_description_options) {
if (!options.transport_options.ice_restart) {
CopyCandidatesFromSessionDescription(pc_->local_description(),
options.mid, answer.get());
}
}
}
PostCreateSessionDescriptionSucceeded(request.observer, std::move(answer));
}
void WebRtcSessionDescriptionFactory::FailPendingRequests(
const std::string& reason) {
RTC_DCHECK(signaling_thread_->IsCurrent());
while (!create_session_description_requests_.empty()) {
const CreateSessionDescriptionRequest& request =
create_session_description_requests_.front();
PostCreateSessionDescriptionFailed(request.observer,
((request.type == CreateSessionDescriptionRequest::kOffer) ?
"CreateOffer" : "CreateAnswer") + reason);
create_session_description_requests_.pop();
}
}
void WebRtcSessionDescriptionFactory::PostCreateSessionDescriptionFailed(
CreateSessionDescriptionObserver* observer, const std::string& error) {
CreateSessionDescriptionMsg* msg = new CreateSessionDescriptionMsg(observer);
msg->error = error;
signaling_thread_->Post(RTC_FROM_HERE, this,
MSG_CREATE_SESSIONDESCRIPTION_FAILED, msg);
RTC_LOG(LS_ERROR) << "Create SDP failed: " << error;
}
void WebRtcSessionDescriptionFactory::PostCreateSessionDescriptionSucceeded(
CreateSessionDescriptionObserver* observer,
std::unique_ptr<SessionDescriptionInterface> description) {
CreateSessionDescriptionMsg* msg = new CreateSessionDescriptionMsg(observer);
msg->description = std::move(description);
signaling_thread_->Post(RTC_FROM_HERE, this,
MSG_CREATE_SESSIONDESCRIPTION_SUCCESS, msg);
}
void WebRtcSessionDescriptionFactory::OnCertificateRequestFailed() {
RTC_DCHECK(signaling_thread_->IsCurrent());
RTC_LOG(LS_ERROR) << "Asynchronous certificate generation request failed.";
certificate_request_state_ = CERTIFICATE_FAILED;
FailPendingRequests(kFailedDueToIdentityFailed);
}
void WebRtcSessionDescriptionFactory::SetCertificate(
const rtc::scoped_refptr<rtc::RTCCertificate>& certificate) {
RTC_DCHECK(certificate);
RTC_LOG(LS_VERBOSE) << "Setting new certificate.";
certificate_request_state_ = CERTIFICATE_SUCCEEDED;
SignalCertificateReady(certificate);
transport_desc_factory_.set_certificate(certificate);
transport_desc_factory_.set_secure(cricket::SEC_ENABLED);
while (!create_session_description_requests_.empty()) {
if (create_session_description_requests_.front().type ==
CreateSessionDescriptionRequest::kOffer) {
InternalCreateOffer(create_session_description_requests_.front());
} else {
InternalCreateAnswer(create_session_description_requests_.front());
}
create_session_description_requests_.pop();
}
}
} // namespace webrtc