webrtc 中有关 socket 运行机制以及 stun 收发过程 及 Candidates 生成流程分析
作者：互联网
----------------------------------------------------------------------------------------------------------------------------------------
一分钟快速搭建 rtmpd 服务器: https://blog.csdn.net/freeabc/article/details/102880984
软件下载地址: http://www.qiyicc.com/download/rtmpd.rar
github 地址：https://github.com/superconvert/smart_rtmpd
-----------------------------------------------------------------------------------------------------------------------------------------
webrtc 中有关 socket 运行机制以及 stun 收发过程 及 Candidates 生成流程分析
//*******************************************************************************************
//
// webrtc 内部很多创建 socket 的地方，这个需要调用类厂 BasicPacketSocketFactory , 下面
// 这一小段就是分析 BasicPacketSocketFactory 的创建，以及内部管理的 socket 的部分流程
//
//*******************************************************************************************
AsyncPacketSocket* BasicPacketSocketFactory::CreateUdpSocket(
const SocketAddress& address,
uint16_t min_port,
uint16_t max_port) {
// UDP sockets are simple.
// 参见下面的 SocketDispatcher
AsyncSocket* socket =
socket_factory()->CreateAsyncSocket(address.family(), SOCK_DGRAM);
if (!socket) {
return NULL;
}
//----------------------------------------------------------------------------
// 这个 BindSocket 最终会调用系统的 bind
//----------------------------------------------------------------------------
if (BindSocket(socket, address, min_port, max_port) < 0) {
RTC_LOG(LS_ERROR) << "UDP bind failed with error " << socket->GetError();
delete socket;
return NULL;
}
//----------------------------------------------------------------------------------------
// 这个里面绑定了读和写事件到 AsyncUDPSocket::OnReadEvent , AsyncUDPSocket::OnWriteEvent
//----------------------------------------------------------------------------------------
return new AsyncUDPSocket(socket);
}
1. 创建 BasicPacketSocketFactory
./pc/peer_connection_factory.cc
BasicPacketSocketFactory 是 PeerConnectionFactory::Initialize() 中创建的
default_socket_factory_.reset(new rtc::BasicPacketSocketFactory(network_thread_));
2.
./sdk/android/src/jni/pc/peer_connection_factory.cc
而 network_thread_ 则是 接口 CreatePeerConnectionFactoryForJava 里的
std::unique_ptr<rtc::Thread> network_thread = rtc::Thread::CreateWithSocketServer();
其实就是这个
std::unique_ptr<Thread> Thread::CreateWithSocketServer() {
return std::unique_ptr<Thread>(new Thread(SocketServer::CreateDefault()));
}
其实就是创建了 PhysicalSocketServer
std::unique_ptr<SocketServer> SocketServer::CreateDefault() {
#if defined(__native_client__)
return std::unique_ptr<SocketServer>(new rtc::NullSocketServer);
#else
return std::unique_ptr<SocketServer>(new rtc::PhysicalSocketServer);
#endif
}
Thread 继承于 class RTC_LOCKABLE RTC_EXPORT Thread : public MessageQueue, public webrtc::TaskQueueBase
构造函数 Thread(SocketServer* ss)把 ss 赋值给基类 MessageQueue，基类接口通过 socketserver 返回这个对象
SocketServer* MessageQueue::socketserver() {
return ss_;
}
所以上面的这句话 socket_factory()->CreateAsyncSocket 其实就是调用
./rtc_base/physical_socket_server.cc
AsyncSocket* PhysicalSocketServer::CreateAsyncSocket(int family, int type) {
SocketDispatcher* dispatcher = new SocketDispatcher(this);
// 这个里面通过 PhysicalSocket::Create 创建一个套接字
if (dispatcher->Create(family, type)) {
return dispatcher;
} else {
delete dispatcher;
return nullptr;
}
}
//******************************************************************************
//
// 下面这段是讲述 socket 怎么接收数据的，和上述流程没任何关系
//
//******************************************************************************
上述流程中，有一个这个函数调用，
std::unique_ptr<Thread> Thread::CreateWithSocketServer() {
return std::unique_ptr<Thread>(new Thread(SocketServer::CreateDefault()));
}
创建一个带线程的 socket 这个线程的 Run 如下：
void Thread::Run() {
ProcessMessages(kForever);
}
// 这个里面不断的 Get 最新的 message 进行处理
bool Thread::ProcessMessages(int cmsLoop) {
// Using ProcessMessages with a custom clock for testing and a time greater
// than 0 doesn't work, since it's not guaranteed to advance the custom
// clock's time, and may get stuck in an infinite loop.
RTC_DCHECK(GetClockForTesting() == nullptr || cmsLoop == 0 ||
cmsLoop == kForever);
int64_t msEnd = (kForever == cmsLoop) ? 0 : TimeAfter(cmsLoop);
int cmsNext = cmsLoop;
while (true) {
#if defined(WEBRTC_MAC)
ScopedAutoReleasePool pool;
#endif
Message msg;
if (!Get(&msg, cmsNext))
return !IsQuitting();
Dispatch(&msg);
if (cmsLoop != kForever) {
cmsNext = static_cast<int>(TimeUntil(msEnd));
if (cmsNext < 0)
return true;
}
}
}
// 其实就是基类的 MessageQueue 的接口
bool MessageQueue::Get(Message* pmsg, int cmsWait, bool process_io)
// 看到这个 ss_ 了吗，就是 SocketServer::CreateDefault() 也就是 PhysicalSocketServer::Wait 接口
if (!ss_->Wait(static_cast<int>(cmsNext), process_io))
这个地方监听所有的 socket 操作，三个版本的都有 win, linux，随便找一个分析
./rtc_base/physical_socket_server.cc
bool PhysicalSocketServer::Wait(int cmsWait, bool process_io)
return WaitEpoll(cmsWait, signal_wakeup_);
bool PhysicalSocketServer::WaitEpoll(int cmsWait)
ProcessEvents(pdispatcher, readable, writable, check_error);
static void ProcessEvents(Dispatcher* dispatcher, bool readable, bool writable, bool check_error)
// 这里就是 SocketDispatcher -
dispatcher->OnEvent(ff, errcode);
void SocketDispatcher::OnEvent(uint32_t ff, int err)
如果是读，这里假设是 UDP
SignalReadEvent(this);
./rtc_base/async_udp_socket.cc
void AsyncUDPSocket::OnReadEvent(AsyncSocket* socket)
SignalReadPacket(this, buf_, static_cast<size_t>(len), remote_addr,
(timestamp > -1 ? timestamp : TimeMicros()));
./p2p/base/stun_port.cc
void UDPPort::OnReadPacket(rtc::AsyncPacketSocket* socket,
const char* data,
size_t size,
const rtc::SocketAddress& remote_addr,
const int64_t& packet_time_us)
//******************************************************************************
//
// 下面就分析了有关 webrtc stun 流程的部分
//
//******************************************************************************
1. 从这里开始分析，这个的调用参考 createPeerConnection 流程
JsepTransportController::MaybeStartGathering
2. 这个 ice_transport 就是 P2PTransportChannel 对象
dtls->ice_transport()->MaybeStartGathering();
3. 第一次创建流程
./p2p/base/p2p_transport_channel.cc
P2PTransportChannel::MaybeStartGathering
//------------------------------------------------------------
// 这个就是创建一个 PortAllocatorSession 并把信号挂接 P2PTransportChannel
//------------------------------------------------------------
AddAllocatorSession(allocator_->CreateSession(
transport_name(), component(), ice_parameters_.ufrag,
ice_parameters_.pwd));
// 进行 PortAllocatorSession 接口的调用
allocator_sessions_.back()->StartGettingPorts();
3.1
这个 allocator_ 来自下面的函数调用，我们看出 就是 JsepTransportController 的成员 port_allocator_
./pc/jsep_transport_controller.cc
rtc::scoped_refptr<webrtc::IceTransportInterface>
JsepTransportController::CreateIceTransport(const std::string& transport_name, bool rtcp) {
int component = rtcp ? cricket::ICE_CANDIDATE_COMPONENT_RTCP : cricket::ICE_CANDIDATE_COMPONENT_RTP;
IceTransportInit init;
init.set_port_allocator(port_allocator_);
init.set_async_resolver_factory(async_resolver_factory_);
init.set_event_log(config_.event_log);
return config_.ice_transport_factory->CreateIceTransport(transport_name, component, std::move(init));
}
./api/ice_transport_factory.cc
rtc::scoped_refptr<IceTransportInterface> CreateIceTransport(IceTransportInit init) {
return new rtc::RefCountedObject<IceTransportWithTransportChannel>(
std::make_unique<cricket::P2PTransportChannel>(
"", 0, init.port_allocator(), init.async_resolver_factory(), init.event_log()));
}
3.2
我们跟踪一下 port_allocator_ 是在 JsepTransportController 初始化过程中传递过来的，我们分析 JsepTransportController
初始化，发现其实就是来自 PeerConnection 的 port_allocator_ 对象
./pc/peer_connection.cc
bool PeerConnection::Initialize(const PeerConnectionInterface::RTCConfiguration& configuration,
PeerConnectionDependencies dependencies)
// 传递过来的。。。。。。
port_allocator_ = std::move(dependencies.allocator);
... ...
// 赋值给 JsepTransportController
transport_controller_.reset(new JsepTransportController(
signaling_thread(), network_thread(), port_allocator_.get(),
async_resolver_factory_.get(), config));
3.3
我们分析 PeerConnection 的初始化过程中, port_allocator_ 的产生过程
./pc/peer_connection_factory.cc
rtc::scoped_refptr<PeerConnectionInterface>
PeerConnectionFactory::CreatePeerConnection(const PeerConnectionInterface::RTCConfiguration& configuration,
PeerConnectionDependencies dependencies)
if (!dependencies.allocator) {
rtc::PacketSocketFactory* packet_socket_factory;
if (dependencies.packet_socket_factory)
packet_socket_factory = dependencies.packet_socket_factory.get();
else
// 这个就是 BasicPacketSocketFactory 参见上面的分析
packet_socket_factory = default_socket_factory_.get();
network_thread_->Invoke<void>(RTC_FROM_HERE, [this, &configuration,
&dependencies,
&packet_socket_factory]() {
//------------------------------------------------------
// 这个就是我们要追踪的 port_allocator_ !!!!!!!!!!!!
//------------------------------------------------------
dependencies.allocator = std::make_unique<cricket::BasicPortAllocator>(
default_network_manager_.get(), packet_socket_factory, configuration.turn_customizer);
});
}
rtc::scoped_refptr<PeerConnection> pc(new rtc::RefCountedObject<PeerConnection>(this, std::move(event_log),
std::move(call)));
ActionsBeforeInitializeForTesting(pc);
if (!pc->Initialize(configuration, std::move(dependencies))) {
return nullptr;
}
上述函数被下面这个调用，我们发现这个里面 dependencies.allocator 为空，因此 port_allocator_ 是在上面的步骤中分配的
./sdk/android/src/jni/pc/peer_connection_factory.cc
static jlong JNI_PeerConnectionFactory_CreatePeerConnection(
JNIEnv* jni,
jlong factory,
const JavaParamRef<jobject>& j_rtc_config,
const JavaParamRef<jobject>& j_constraints,
jlong observer_p,
const JavaParamRef<jobject>& j_sslCertificateVerifier)
PeerConnectionDependencies peer_connection_dependencies(observer.get());
if (!j_sslCertificateVerifier.is_null()) {
peer_connection_dependencies.tls_cert_verifier = std::make_unique<SSLCertificateVerifierWrapper>(
jni, j_sslCertificateVerifier);
}
rtc::scoped_refptr<PeerConnectionInterface> pc =
PeerConnectionFactoryFromJava(factory)->CreatePeerConnection(rtc_config,
std::move(peer_connection_dependencies));
3.4 我们继续分析 BasicPortAllocator 的接口 CreateSession
./p2p/base/port_allocator.cc
std::unique_ptr<PortAllocatorSession> PortAllocator::CreateSession(
const std::string& content_name,
int component,
const std::string& ice_ufrag,
const std::string& ice_pwd) {
CheckRunOnValidThreadAndInitialized();
auto session = std::unique_ptr<PortAllocatorSession>(
CreateSessionInternal(content_name, component, ice_ufrag, ice_pwd));
session->SetCandidateFilter(candidate_filter());
return session;
}
./p2p/client/basic_port_allocator.cc
PortAllocatorSession* BasicPortAllocator::CreateSessionInternal(const std::string& content_name,
int component, const std::string& ice_ufrag, const std::string& ice_pwd) {
CheckRunOnValidThreadAndInitialized();
PortAllocatorSession* session = new BasicPortAllocatorSession(this, content_name, component, ice_ufrag, ice_pwd);
session->SignalIceRegathering.connect(this, &BasicPortAllocator::OnIceRegathering);
return session;
}
4.
./p2p/client/basic_port_allocator.cc
void BasicPortAllocatorSession::StartGettingPorts() {
RTC_DCHECK_RUN_ON(network_thread_);
state_ = SessionState::GATHERING;
if (!socket_factory_) {
owned_socket_factory_.reset(
new rtc::BasicPacketSocketFactory(network_thread_));
socket_factory_ = owned_socket_factory_.get();
}
network_thread_->Post(RTC_FROM_HERE, this, MSG_CONFIG_START);
RTC_LOG(LS_INFO) << "Start getting ports with turn_port_prune_policy "
<< turn_port_prune_policy_;
}
5.
void BasicPortAllocatorSession::OnMessage(rtc::Message* message) {
switch (message->message_id) {
case MSG_CONFIG_START:
GetPortConfigurations();
break;
case MSG_CONFIG_READY:
OnConfigReady(static_cast<PortConfiguration*>(message->pdata));
break;
case MSG_ALLOCATE:
OnAllocate();
break;
case MSG_SEQUENCEOBJECTS_CREATED:
OnAllocationSequenceObjectsCreated();
break;
case MSG_CONFIG_STOP:
OnConfigStop();
break;
default:
RTC_NOTREACHED();
}
}
void BasicPortAllocatorSession::GetPortConfigurations() {
RTC_DCHECK_RUN_ON(network_thread_);
PortConfiguration* config =
new PortConfiguration(allocator_->stun_servers(), username(), password());
for (const RelayServerConfig& turn_server : allocator_->turn_servers()) {
config->AddRelay(turn_server);
}
ConfigReady(config);
}
void BasicPortAllocatorSession::ConfigReady(PortConfiguration* config) {
RTC_DCHECK_RUN_ON(network_thread_);
network_thread_->Post(RTC_FROM_HERE, this, MSG_CONFIG_READY, config);
}
6.
void BasicPortAllocatorSession::OnConfigReady(PortConfiguration* config) {
RTC_DCHECK_RUN_ON(network_thread_);
if (config) {
configs_.push_back(config);
}
AllocatePorts();
}
void BasicPortAllocatorSession::AllocatePorts() {
RTC_DCHECK_RUN_ON(network_thread_);
network_thread_->Post(RTC_FROM_HERE, this, MSG_ALLOCATE);
}
7.
void BasicPortAllocatorSession::OnAllocate() {
RTC_DCHECK_RUN_ON(network_thread_);
if (network_manager_started_ && !IsStopped()) {
bool disable_equivalent_phases = true;
DoAllocate(disable_equivalent_phases);
}
allocation_started_ = true;
}
void BasicPortAllocatorSession::DoAllocate(bool disable_equivalent)
AllocationSequence* sequence = new AllocationSequence(this, networks[i], config, sequence_flags);
sequence->SignalPortAllocationComplete.connect(
this, &BasicPortAllocatorSession::OnPortAllocationComplete);
sequence->Init();
sequence->Start();
sequences_.push_back(sequence);
done_signal_needed = true;
network_thread_->Post(RTC_FROM_HERE, this, MSG_SEQUENCEOBJECTS_CREATED);
7.1 sequence->Init() 这个里面创建了一个 UDP 套接字，并绑定读取接口
./p2p/client/basic_port_allocator.cc
void AllocationSequence::Init() {
if (IsFlagSet(PORTALLOCATOR_ENABLE_SHARED_SOCKET)) {
udp_socket_.reset(session_->socket_factory()->CreateUdpSocket(
rtc::SocketAddress(network_->GetBestIP(), 0),
session_->allocator()->min_port(), session_->allocator()->max_port()));
if (udp_socket_) {
udp_socket_->SignalReadPacket.connect(this,
&AllocationSequence::OnReadPacket);
}
// Continuing if |udp_socket_| is NULL, as local TCP and RelayPort using TCP
// are next available options to setup a communication channel.
}
}
7.2 sequence->Start()
session_->network_thread()->Post(RTC_FROM_HERE, this, MSG_ALLOCATION_PHASE);
7.3
void AllocationSequence::OnMessage(rtc::Message* msg) {
RTC_DCHECK(rtc::Thread::Current() == session_->network_thread());
RTC_DCHECK(msg->message_id == MSG_ALLOCATION_PHASE);
const char* const PHASE_NAMES[kNumPhases] = {"Udp", "Relay", "Tcp"};
// Perform all of the phases in the current step.
RTC_LOG(LS_INFO) << network_->ToString() << ": Allocation Phase=" << PHASE_NAMES[phase_];
switch (phase_) {
case PHASE_UDP:
CreateUDPPorts();
CreateStunPorts();
break;
case PHASE_RELAY:
CreateRelayPorts();
break;
case PHASE_TCP:
CreateTCPPorts();
state_ = kCompleted;
break;
default:
RTC_NOTREACHED();
}
if (state() == kRunning) {
++phase_;
session_->network_thread()->PostDelayed(RTC_FROM_HERE,
session_->allocator()->step_delay(),
this, MSG_ALLOCATION_PHASE);
} else {
// If all phases in AllocationSequence are completed, no allocation
// steps needed further. Canceling pending signal.
session_->network_thread()->Clear(this, MSG_ALLOCATION_PHASE);
SignalPortAllocationComplete(this);
}
}
7.4
void AllocationSequence::CreateUDPPorts()
// 把上述创建的 udp_socket_
port = UDPPort::Create(
session_->network_thread(), session_->socket_factory(), network_,
session_->allocator()->min_port(), session_->allocator()->max_port(),
session_->username(), session_->password(),
session_->allocator()->origin(), emit_local_candidate_for_anyaddress,
session_->allocator()->stun_candidate_keepalive_interval());
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// 参见下面的 AddAllocatedPort 主要是 OnCandidateReady, OnPortComplete
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
session_->AddAllocatedPort(port.release(), this, true);
7.4.1
./p2p/base/stun_port.h
static std::unique_ptr<UDPPort> Create(
rtc::Thread* thread,
rtc::PacketSocketFactory* factory,
rtc::Network* network,
rtc::AsyncPacketSocket* socket,
const std::string& username,
const std::string& password,
const std::string& origin,
bool emit_local_for_anyaddress,
absl::optional<int> stun_keepalive_interval) {
// Using `new` to access a non-public constructor.
auto port = absl::WrapUnique(new UDPPort(thread, factory, network, socket,
username, password, origin,
emit_local_for_anyaddress));
port->set_stun_keepalive_delay(stun_keepalive_interval);
if (!port->Init()) {
return nullptr;
}
return port;
}
7.4.2
bool UDPPort::Init()
stun_keepalive_lifetime_ = GetStunKeepaliveLifetime();
if (!SharedSocket()) {
RTC_DCHECK(socket_ == nullptr);
//---------------------------------------------------------------------------------
// 这里的 socket_factory 其实就是上面的 BasicPacketSocketFactory 的接口，创建 socket 并绑定
//---------------------------------------------------------------------------------
socket_ = socket_factory()->CreateUdpSocket(
rtc::SocketAddress(Network()->GetBestIP(), 0), min_port(), max_port());
if (!socket_) {
RTC_LOG(LS_WARNING) << ToString() << ": UDP socket creation failed";
return false;
}
socket_->SignalReadPacket.connect(this, &UDPPort::OnReadPacket);
}
socket_->SignalSentPacket.connect(this, &UDPPort::OnSentPacket);
socket_->SignalReadyToSend.connect(this, &UDPPort::OnReadyToSend);
socket_->SignalAddressReady.connect(this, &UDPPort::OnLocalAddressReady);
requests_.SignalSendPacket.connect(this, &UDPPort::OnSendPacket);
7.5
void BasicPortAllocatorSession::AddAllocatedPort(Port* port,
AllocationSequence* seq,
bool prepare_address) {
RTC_DCHECK_RUN_ON(network_thread_);
if (!port)
return;
RTC_LOG(LS_INFO) << "Adding allocated port for " << content_name();
port->set_content_name(content_name());
port->set_component(component());
port->set_generation(generation());
if (allocator_->proxy().type != rtc::PROXY_NONE)
port->set_proxy(allocator_->user_agent(), allocator_->proxy());
port->set_send_retransmit_count_attribute(
(flags() & PORTALLOCATOR_ENABLE_STUN_RETRANSMIT_ATTRIBUTE) != 0);
PortData data(port, seq);
ports_.push_back(data);
port->SignalCandidateReady.connect(
this, &BasicPortAllocatorSession::OnCandidateReady);
port->SignalCandidateError.connect(
this, &BasicPortAllocatorSession::OnCandidateError);
port->SignalPortComplete.connect(this,
&BasicPortAllocatorSession::OnPortComplete);
port->SignalDestroyed.connect(this,
&BasicPortAllocatorSession::OnPortDestroyed);
port->SignalPortError.connect(this, &BasicPortAllocatorSession::OnPortError);
RTC_LOG(LS_INFO) << port->ToString() << ": Added port to allocator";
if (prepare_address)
port->PrepareAddress();
}
7.6
void UDPPort::PrepareAddress() {
RTC_DCHECK(requests_.empty());
if (socket_->GetState() == rtc::AsyncPacketSocket::STATE_BOUND) {
OnLocalAddressReady(socket_, socket_->GetLocalAddress());
}
}
void UDPPort::OnLocalAddressReady(rtc::AsyncPacketSocket* socket,
const rtc::SocketAddress& address) {
// When adapter enumeration is disabled and binding to the any address, the
// default local address will be issued as a candidate instead if
// |emit_local_for_anyaddress| is true. This is to allow connectivity for
// applications which absolutely requires a HOST candidate.
rtc::SocketAddress addr = address;
// If MaybeSetDefaultLocalAddress fails, we keep the "any" IP so that at
// least the port is listening.
MaybeSetDefaultLocalAddress(&addr);
AddAddress(addr, addr, rtc::SocketAddress(), UDP_PROTOCOL_NAME, "", "",
LOCAL_PORT_TYPE, ICE_TYPE_PREFERENCE_HOST, 0, "", false);
MaybePrepareStunCandidate();
}
void UDPPort::MaybePrepareStunCandidate() {
// Sending binding request to the STUN server if address is available to
// prepare STUN candidate.
if (!server_addresses_.empty()) {
SendStunBindingRequests();
} else {
// Port is done allocating candidates.
MaybeSetPortCompleteOrError();
}
}
7.7 这个地方发送 stun 的绑定命令到 stun 服务器
void UDPPort::SendStunBindingRequests() {
// We will keep pinging the stun server to make sure our NAT pin-hole stays
// open until the deadline (specified in SendStunBindingRequest).
RTC_DCHECK(requests_.empty());
for (ServerAddresses::const_iterator it = server_addresses_.begin();
it != server_addresses_.end(); ++it) {
SendStunBindingRequest(*it);
}
}
//--------------------------------------------------------------------------------
// stun 服务器响应流程分析 socket 接收数据开始
//--------------------------------------------------------------------------------
所有的 stun 信令都在这个里面
// 这个流程上面已经分析过了
7.7.1
bool MessageQueue::Get(Message* pmsg, int cmsWait, bool process_io)
// 看到这个 ss_ 了吗，就是 SocketServer::CreateDefault() 也就是 PhysicalSocketServer::Wait 接口
if (!ss_->Wait(static_cast<int>(cmsNext), process_io))
7.7.2
bool PhysicalSocketServer::Wait(int cmsWait, bool process_io)
return WaitEpoll(cmsWait);
7.7.3
bool PhysicalSocketServer::WaitEpoll(int cmsWait)
ProcessEvents(pdispatcher, readable, writable, check_error);
7.7.4
static void ProcessEvents(Dispatcher* dispatcher,
bool readable,
bool writable,
bool check_error)
dispatcher->OnEvent(ff, errcode);
7.7.5
./rtc_base/physical_socket_server.cc
void SocketDispatcher::OnEvent(uint32_t ff, int err)
SignalReadEvent(this);
7.7.6
./rtc_base/async_udp_socket.cc
void AsyncUDPSocket::OnReadEvent(AsyncSocket* socket)
SignalReadPacket(this, buf_, static_cast<size_t>(len), remote_addr,
(timestamp > -1 ? timestamp : TimeMicros()));
7.7.7
./p2p/base/stun_port.cc
void UDPPort::OnReadPacket(rtc::AsyncPacketSocket* socket,
const char* data,
size_t size,
const rtc::SocketAddress& remote_addr,
const int64_t& packet_time_us)
requests_.CheckResponse(data, size);
OnReadPacket 绑定 AsyncUDPSocket::
7.7.8
./p2p/base/stun_request.cc
bool StunRequestManager::CheckResponse(StunMessage* msg)
request->OnResponse(msg);
7.7.9
./p2p/base/stun_port.cc
void StunBindingRequest::OnResponse(StunMessage* response)
port_->OnStunBindingRequestSucceeded(this->Elapsed(), server_addr_, addr);
7.8 stun 成功，则进入
./p2p/base/stun_port.cc
void UDPPort::OnStunBindingRequestSucceeded(
int rtt_ms,
const rtc::SocketAddress& stun_server_addr,
const rtc::SocketAddress& stun_reflected_addr)
AddAddress(stun_reflected_addr, socket_->GetLocalAddress(), related_address,
UDP_PROTOCOL_NAME, "", "", STUN_PORT_TYPE,
ICE_TYPE_PREFERENCE_SRFLX, 0, url.str(), false);
7.9
void Port::AddAddress(const rtc::SocketAddress& address,
const rtc::SocketAddress& base_address,
const rtc::SocketAddress& related_address,
const std::string& protocol,
const std::string& relay_protocol,
const std::string& tcptype,
const std::string& type,
uint32_t type_preference,
uint32_t relay_preference,
const std::string& url,
bool is_final)
FinishAddingAddress(c, is_final);
7.10
void Port::FinishAddingAddress(const Candidate& c, bool is_final) {
candidates_.push_back(c);
SignalCandidateReady(this, c);
PostAddAddress(is_final);
}
7.11
./p2p/client/basic_port_allocator.cc
void BasicPortAllocatorSession::OnCandidateReady(Port* port, const Candidate& c)
SignalCandidatesReady(this, candidates);
7.12
./p2p/base/p2p_transport_channel.cc
void P2PTransportChannel::OnCandidatesReady(
PortAllocatorSession* session,
const std::vector<Candidate>& candidates) {
RTC_DCHECK_RUN_ON(network_thread_);
for (size_t i = 0; i < candidates.size(); ++i) {
SignalCandidateGathered(this, candidates[i]);
}
}
7.13
./pc/jsep_transport_controller.cc
void JsepTransportController::OnTransportCandidateGathered_n(
cricket::IceTransportInternal* transport,
const cricket::Candidate& candidate) {
RTC_DCHECK(network_thread_->IsCurrent());
// We should never signal peer-reflexive candidates.
if (candidate.type() == cricket::PRFLX_PORT_TYPE) {
RTC_NOTREACHED();
return;
}
std::string transport_name = transport->transport_name();
invoker_.AsyncInvoke<void>(
RTC_FROM_HERE, signaling_thread_, [this, transport_name, candidate] {
SignalIceCandidatesGathered(transport_name, {candidate});
});
}
7.14
./pc/peer_connection.cc
void PeerConnection::OnTransportControllerCandidatesGathered(
const std::string& transport_name,
const cricket::Candidates& candidates) {
int sdp_mline_index;
if (!GetLocalCandidateMediaIndex(transport_name, &sdp_mline_index)) {
RTC_LOG(LS_ERROR)
<< "OnTransportControllerCandidatesGathered: content name "
<< transport_name << " not found";
return;
}
for (cricket::Candidates::const_iterator citer = candidates.begin();
citer != candidates.end(); ++citer) {
// Use transport_name as the candidate media id.
std::unique_ptr<JsepIceCandidate> candidate(
new JsepIceCandidate(transport_name, sdp_mline_index, *citer));
if (local_description()) {
mutable_local_description()->AddCandidate(candidate.get());
}
OnIceCandidate(std::move(candidate));
}
}
void PeerConnection::OnIceCandidate(
std::unique_ptr<IceCandidateInterface> candidate) {
if (IsClosed()) {
return;
}
ReportIceCandidateCollected(candidate->candidate());
// 这个地方回调到 Java 层的接口，并把自己的 candidate 发送给对方
Observer()->OnIceCandidate(candidate.get());
}
8.
void BasicPortAllocatorSession::OnAllocationSequenceObjectsCreated() {
RTC_DCHECK_RUN_ON(network_thread_);
allocation_sequences_created_ = true;
// Send candidate allocation complete signal if we have no sequences.
MaybeSignalCandidatesAllocationDone();
}
./p2p/base/p2p_transport_channel.cc
void P2PTransportChannel::OnCandidatesAllocationDone(
PortAllocatorSession* session) {
RTC_DCHECK_RUN_ON(network_thread_);
if (config_.gather_continually()) {
RTC_LOG(LS_INFO) << "P2PTransportChannel: " << transport_name()
<< ", component " << component()
<< " gathering complete, but using continual "
"gathering so not changing gathering state.";
return;
}
gathering_state_ = kIceGatheringComplete;
RTC_LOG(LS_INFO) << "P2PTransportChannel: " << transport_name()
<< ", component " << component() << " gathering complete";
SignalGatheringState(this);
}
./pc/jsep_transport_controller.cc
void JsepTransportController::OnTransportGatheringState_n(
cricket::IceTransportInternal* transport) {
RTC_DCHECK(network_thread_->IsCurrent());
UpdateAggregateStates_n();
}
标签：std,const,socket,rtc,RTC,Candidates,stun,port 来源： https://blog.csdn.net/freeabc/article/details/106000923