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/*
* Copyright 2012 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/data_channel.h"
#include <memory>
#include <string>
#include <utility>
#include "media/sctp/sctp_transport_internal.h"
#include "pc/sctp_utils.h"
#include "rtc_base/checks.h"
#include "rtc_base/location.h"
#include "rtc_base/logging.h"
#include "rtc_base/ref_counted_object.h"
#include "rtc_base/thread.h"
namespace webrtc {
static size_t kMaxQueuedReceivedDataBytes = 16 * 1024 * 1024;
static size_t kMaxQueuedSendDataBytes = 16 * 1024 * 1024;
namespace {
static std::atomic<int> g_unique_id{0};
int GenerateUniqueId() {
return ++g_unique_id;
}
} // namespace
InternalDataChannelInit::InternalDataChannelInit(const DataChannelInit& base)
: DataChannelInit(base), open_handshake_role(kOpener) {
// If the channel is externally negotiated, do not send the OPEN message.
if (base.negotiated) {
open_handshake_role = kNone;
} else {
// Datachannel is externally negotiated. Ignore the id value.
// Specified in createDataChannel, WebRTC spec section 6.1 bullet 13.
id = -1;
}
// Backwards compatibility: If base.maxRetransmits or base.maxRetransmitTime
// have been set to -1, unset them.
if (maxRetransmits && *maxRetransmits == -1) {
RTC_LOG(LS_ERROR)
<< "Accepting maxRetransmits = -1 for backwards compatibility";
maxRetransmits = absl::nullopt;
}
if (maxRetransmitTime && *maxRetransmitTime == -1) {
RTC_LOG(LS_ERROR)
<< "Accepting maxRetransmitTime = -1 for backwards compatibility";
maxRetransmitTime = absl::nullopt;
}
}
bool SctpSidAllocator::AllocateSid(rtc::SSLRole role, int* sid) {
int potential_sid = (role == rtc::SSL_CLIENT) ? 0 : 1;
while (!IsSidAvailable(potential_sid)) {
potential_sid += 2;
if (potential_sid > static_cast<int>(cricket::kMaxSctpSid)) {
return false;
}
}
*sid = potential_sid;
used_sids_.insert(potential_sid);
return true;
}
bool SctpSidAllocator::ReserveSid(int sid) {
if (!IsSidAvailable(sid)) {
return false;
}
used_sids_.insert(sid);
return true;
}
void SctpSidAllocator::ReleaseSid(int sid) {
auto it = used_sids_.find(sid);
if (it != used_sids_.end()) {
used_sids_.erase(it);
}
}
bool SctpSidAllocator::IsSidAvailable(int sid) const {
if (sid < static_cast<int>(cricket::kMinSctpSid) ||
sid > static_cast<int>(cricket::kMaxSctpSid)) {
return false;
}
return used_sids_.find(sid) == used_sids_.end();
}
bool DataChannel::PacketQueue::Empty() const {
return packets_.empty();
}
std::unique_ptr<DataBuffer> DataChannel::PacketQueue::PopFront() {
RTC_DCHECK(!packets_.empty());
byte_count_ -= packets_.front()->size();
std::unique_ptr<DataBuffer> packet = std::move(packets_.front());
packets_.pop_front();
return packet;
}
void DataChannel::PacketQueue::PushFront(std::unique_ptr<DataBuffer> packet) {
byte_count_ += packet->size();
packets_.push_front(std::move(packet));
}
void DataChannel::PacketQueue::PushBack(std::unique_ptr<DataBuffer> packet) {
byte_count_ += packet->size();
packets_.push_back(std::move(packet));
}
void DataChannel::PacketQueue::Clear() {
packets_.clear();
byte_count_ = 0;
}
void DataChannel::PacketQueue::Swap(PacketQueue* other) {
size_t other_byte_count = other->byte_count_;
other->byte_count_ = byte_count_;
byte_count_ = other_byte_count;
other->packets_.swap(packets_);
}
rtc::scoped_refptr<DataChannel> DataChannel::Create(
DataChannelProviderInterface* provider,
cricket::DataChannelType dct,
const std::string& label,
const InternalDataChannelInit& config) {
rtc::scoped_refptr<DataChannel> channel(
new rtc::RefCountedObject<DataChannel>(provider, dct, label));
if (!channel->Init(config)) {
return NULL;
}
return channel;
}
bool DataChannel::IsSctpLike(cricket::DataChannelType type) {
return type == cricket::DCT_SCTP || type == cricket::DCT_MEDIA_TRANSPORT ||
type == cricket::DCT_DATA_CHANNEL_TRANSPORT ||
type == cricket::DCT_DATA_CHANNEL_TRANSPORT_SCTP;
}
DataChannel::DataChannel(DataChannelProviderInterface* provider,
cricket::DataChannelType dct,
const std::string& label)
: internal_id_(GenerateUniqueId()),
label_(label),
observer_(nullptr),
state_(kConnecting),
messages_sent_(0),
bytes_sent_(0),
messages_received_(0),
bytes_received_(0),
buffered_amount_(0),
data_channel_type_(dct),
provider_(provider),
handshake_state_(kHandshakeInit),
connected_to_provider_(false),
send_ssrc_set_(false),
receive_ssrc_set_(false),
writable_(false),
send_ssrc_(0),
receive_ssrc_(0) {}
bool DataChannel::Init(const InternalDataChannelInit& config) {
if (data_channel_type_ == cricket::DCT_RTP) {
if (config.reliable || config.id != -1 || config.maxRetransmits ||
config.maxRetransmitTime) {
RTC_LOG(LS_ERROR) << "Failed to initialize the RTP data channel due to "
"invalid DataChannelInit.";
return false;
}
handshake_state_ = kHandshakeReady;
} else if (IsSctpLike(data_channel_type_)) {
if (config.id < -1 ||
(config.maxRetransmits && *config.maxRetransmits < 0) ||
(config.maxRetransmitTime && *config.maxRetransmitTime < 0)) {
RTC_LOG(LS_ERROR) << "Failed to initialize the SCTP data channel due to "
"invalid DataChannelInit.";
return false;
}
if (config.maxRetransmits && config.maxRetransmitTime) {
RTC_LOG(LS_ERROR)
<< "maxRetransmits and maxRetransmitTime should not be both set.";
return false;
}
config_ = config;
switch (config_.open_handshake_role) {
case webrtc::InternalDataChannelInit::kNone: // pre-negotiated
handshake_state_ = kHandshakeReady;
break;
case webrtc::InternalDataChannelInit::kOpener:
handshake_state_ = kHandshakeShouldSendOpen;
break;
case webrtc::InternalDataChannelInit::kAcker:
handshake_state_ = kHandshakeShouldSendAck;
break;
}
// Try to connect to the transport in case the transport channel already
// exists.
OnTransportChannelCreated();
// Checks if the transport is ready to send because the initial channel
// ready signal may have been sent before the DataChannel creation.
// This has to be done async because the upper layer objects (e.g.
// Chrome glue and WebKit) are not wired up properly until after this
// function returns.
if (provider_->ReadyToSendData()) {
invoker_.AsyncInvoke<void>(RTC_FROM_HERE, rtc::Thread::Current(),
[this] { OnChannelReady(true); });
}
}
return true;
}
DataChannel::~DataChannel() {}
void DataChannel::RegisterObserver(DataChannelObserver* observer) {
observer_ = observer;
DeliverQueuedReceivedData();
}
void DataChannel::UnregisterObserver() {
observer_ = NULL;
}
bool DataChannel::reliable() const {
if (data_channel_type_ == cricket::DCT_RTP) {
return false;
} else {
return !config_.maxRetransmits && !config_.maxRetransmitTime;
}
}
uint64_t DataChannel::buffered_amount() const {
return buffered_amount_;
}
void DataChannel::Close() {
if (state_ == kClosed)
return;
send_ssrc_ = 0;
send_ssrc_set_ = false;
SetState(kClosing);
// Will send queued data before beginning the underlying closing procedure.
UpdateState();
}
bool DataChannel::Send(const DataBuffer& buffer) {
buffered_amount_ += buffer.size();
if (state_ != kOpen) {
return false;
}
// TODO(jiayl): the spec is unclear about if the remote side should get the
// onmessage event. We need to figure out the expected behavior and change the
// code accordingly.
if (buffer.size() == 0) {
return true;
}
// If the queue is non-empty, we're waiting for SignalReadyToSend,
// so just add to the end of the queue and keep waiting.
if (!queued_send_data_.Empty()) {
// Only SCTP DataChannel queues the outgoing data when the transport is
// blocked.
RTC_DCHECK(IsSctpLike(data_channel_type_));
if (!QueueSendDataMessage(buffer)) {
RTC_LOG(LS_ERROR) << "Closing the DataChannel due to a failure to queue "
"additional data.";
CloseAbruptly();
}
return true;
}
bool success = SendDataMessage(buffer, true);
if (data_channel_type_ == cricket::DCT_RTP) {
return success;
}
// Always return true for SCTP DataChannel per the spec.
return true;
}
void DataChannel::SetReceiveSsrc(uint32_t receive_ssrc) {
RTC_DCHECK(data_channel_type_ == cricket::DCT_RTP);
if (receive_ssrc_set_) {
return;
}
receive_ssrc_ = receive_ssrc;
receive_ssrc_set_ = true;
UpdateState();
}
void DataChannel::SetSctpSid(int sid) {
RTC_DCHECK_LT(config_.id, 0);
RTC_DCHECK_GE(sid, 0);
RTC_DCHECK(IsSctpLike(data_channel_type_));
if (config_.id == sid) {
return;
}
config_.id = sid;
provider_->AddSctpDataStream(sid);
}
void DataChannel::OnClosingProcedureStartedRemotely(int sid) {
if (IsSctpLike(data_channel_type_) && sid == config_.id &&
state_ != kClosing && state_ != kClosed) {
// Don't bother sending queued data since the side that initiated the
// closure wouldn't receive it anyway. See crbug.com/559394 for a lengthy
// discussion about this.
queued_send_data_.Clear();
queued_control_data_.Clear();
// Just need to change state to kClosing, SctpTransport will handle the
// rest of the closing procedure and OnClosingProcedureComplete will be
// called later.
started_closing_procedure_ = true;
SetState(kClosing);
}
}
void DataChannel::OnClosingProcedureComplete(int sid) {
if (IsSctpLike(data_channel_type_) && sid == config_.id) {
// If the closing procedure is complete, we should have finished sending
// all pending data and transitioned to kClosing already.
RTC_DCHECK_EQ(state_, kClosing);
RTC_DCHECK(queued_send_data_.Empty());
DisconnectFromProvider();
SetState(kClosed);
}
}
void DataChannel::OnTransportChannelCreated() {
RTC_DCHECK(IsSctpLike(data_channel_type_));
if (!connected_to_provider_) {
connected_to_provider_ = provider_->ConnectDataChannel(this);
}
// The sid may have been unassigned when provider_->ConnectDataChannel was
// done. So always add the streams even if connected_to_provider_ is true.
if (config_.id >= 0) {
provider_->AddSctpDataStream(config_.id);
}
}
void DataChannel::OnTransportChannelDestroyed() {
// The SctpTransport is going away (for example, because the SCTP m= section
// was rejected), so we need to close abruptly.
CloseAbruptly();
}
// The remote peer request that this channel shall be closed.
void DataChannel::RemotePeerRequestClose() {
RTC_DCHECK(data_channel_type_ == cricket::DCT_RTP);
CloseAbruptly();
}
void DataChannel::SetSendSsrc(uint32_t send_ssrc) {
RTC_DCHECK(data_channel_type_ == cricket::DCT_RTP);
if (send_ssrc_set_) {
return;
}
send_ssrc_ = send_ssrc;
send_ssrc_set_ = true;
UpdateState();
}
void DataChannel::OnDataReceived(const cricket::ReceiveDataParams& params,
const rtc::CopyOnWriteBuffer& payload) {
if (data_channel_type_ == cricket::DCT_RTP && params.ssrc != receive_ssrc_) {
return;
}
if (IsSctpLike(data_channel_type_) && params.sid != config_.id) {
return;
}
if (params.type == cricket::DMT_CONTROL) {
RTC_DCHECK(IsSctpLike(data_channel_type_));
if (handshake_state_ != kHandshakeWaitingForAck) {
// Ignore it if we are not expecting an ACK message.
RTC_LOG(LS_WARNING)
<< "DataChannel received unexpected CONTROL message, sid = "
<< params.sid;
return;
}
if (ParseDataChannelOpenAckMessage(payload)) {
// We can send unordered as soon as we receive the ACK message.
handshake_state_ = kHandshakeReady;
RTC_LOG(LS_INFO) << "DataChannel received OPEN_ACK message, sid = "
<< params.sid;
} else {
RTC_LOG(LS_WARNING)
<< "DataChannel failed to parse OPEN_ACK message, sid = "
<< params.sid;
}
return;
}
RTC_DCHECK(params.type == cricket::DMT_BINARY ||
params.type == cricket::DMT_TEXT);
RTC_LOG(LS_VERBOSE) << "DataChannel received DATA message, sid = "
<< params.sid;
// We can send unordered as soon as we receive any DATA message since the
// remote side must have received the OPEN (and old clients do not send
// OPEN_ACK).
if (handshake_state_ == kHandshakeWaitingForAck) {
handshake_state_ = kHandshakeReady;
}
bool binary = (params.type == cricket::DMT_BINARY);
auto buffer = std::make_unique<DataBuffer>(payload, binary);
if (state_ == kOpen && observer_) {
++messages_received_;
bytes_received_ += buffer->size();
observer_->OnMessage(*buffer.get());
} else {
if (queued_received_data_.byte_count() + payload.size() >
kMaxQueuedReceivedDataBytes) {
RTC_LOG(LS_ERROR) << "Queued received data exceeds the max buffer size.";
queued_received_data_.Clear();
if (data_channel_type_ != cricket::DCT_RTP) {
CloseAbruptly();
}
return;
}
queued_received_data_.PushBack(std::move(buffer));
}
}
void DataChannel::OnChannelReady(bool writable) {
writable_ = writable;
if (!writable) {
return;
}
SendQueuedControlMessages();
SendQueuedDataMessages();
UpdateState();
}
void DataChannel::CloseAbruptly() {
if (state_ == kClosed) {
return;
}
if (connected_to_provider_) {
DisconnectFromProvider();
}
// Closing abruptly means any queued data gets thrown away.
queued_send_data_.Clear();
buffered_amount_ = 0;
queued_control_data_.Clear();
// Still go to "kClosing" before "kClosed", since observers may be expecting
// that.
SetState(kClosing);
SetState(kClosed);
}
void DataChannel::UpdateState() {
// UpdateState determines what to do from a few state variables. Include
// all conditions required for each state transition here for
// clarity. OnChannelReady(true) will send any queued data and then invoke
// UpdateState().
switch (state_) {
case kConnecting: {
if (send_ssrc_set_ == receive_ssrc_set_) {
if (data_channel_type_ == cricket::DCT_RTP && !connected_to_provider_) {
connected_to_provider_ = provider_->ConnectDataChannel(this);
}
if (connected_to_provider_) {
if (handshake_state_ == kHandshakeShouldSendOpen) {
rtc::CopyOnWriteBuffer payload;
WriteDataChannelOpenMessage(label_, config_, &payload);
SendControlMessage(payload);
} else if (handshake_state_ == kHandshakeShouldSendAck) {
rtc::CopyOnWriteBuffer payload;
WriteDataChannelOpenAckMessage(&payload);
SendControlMessage(payload);
}
if (writable_ && (handshake_state_ == kHandshakeReady ||
handshake_state_ == kHandshakeWaitingForAck)) {
SetState(kOpen);
// If we have received buffers before the channel got writable.
// Deliver them now.
DeliverQueuedReceivedData();
}
}
}
break;
}
case kOpen: {
break;
}
case kClosing: {
// Wait for all queued data to be sent before beginning the closing
// procedure.
if (queued_send_data_.Empty() && queued_control_data_.Empty()) {
if (data_channel_type_ == cricket::DCT_RTP) {
// For RTP data channels, we can go to "closed" after we finish
// sending data and the send/recv SSRCs are unset.
if (connected_to_provider_) {
DisconnectFromProvider();
}
if (!send_ssrc_set_ && !receive_ssrc_set_) {
SetState(kClosed);
}
} else {
// For SCTP data channels, we need to wait for the closing procedure
// to complete; after calling RemoveSctpDataStream,
// OnClosingProcedureComplete will end up called asynchronously
// afterwards.
if (connected_to_provider_ && !started_closing_procedure_ &&
config_.id >= 0) {
started_closing_procedure_ = true;
provider_->RemoveSctpDataStream(config_.id);
}
}
}
break;
}
case kClosed:
break;
}
}
void DataChannel::SetState(DataState state) {
if (state_ == state) {
return;
}
state_ = state;
if (observer_) {
observer_->OnStateChange();
}
if (state_ == kOpen) {
SignalOpened(this);
} else if (state_ == kClosed) {
SignalClosed(this);
}
}
void DataChannel::DisconnectFromProvider() {
if (!connected_to_provider_)
return;
provider_->DisconnectDataChannel(this);
connected_to_provider_ = false;
}
void DataChannel::DeliverQueuedReceivedData() {
if (!observer_) {
return;
}
while (!queued_received_data_.Empty()) {
std::unique_ptr<DataBuffer> buffer = queued_received_data_.PopFront();
++messages_received_;
bytes_received_ += buffer->size();
observer_->OnMessage(*buffer);
}
}
void DataChannel::SendQueuedDataMessages() {
if (queued_send_data_.Empty()) {
return;
}
RTC_DCHECK(state_ == kOpen || state_ == kClosing);
while (!queued_send_data_.Empty()) {
std::unique_ptr<DataBuffer> buffer = queued_send_data_.PopFront();
if (!SendDataMessage(*buffer, false)) {
// Return the message to the front of the queue if sending is aborted.
queued_send_data_.PushFront(std::move(buffer));
break;
}
}
}
bool DataChannel::SendDataMessage(const DataBuffer& buffer,
bool queue_if_blocked) {
cricket::SendDataParams send_params;
if (IsSctpLike(data_channel_type_)) {
send_params.ordered = config_.ordered;
// Send as ordered if it is still going through OPEN/ACK signaling.
if (handshake_state_ != kHandshakeReady && !config_.ordered) {
send_params.ordered = true;
RTC_LOG(LS_VERBOSE)
<< "Sending data as ordered for unordered DataChannel "
"because the OPEN_ACK message has not been received.";
}
send_params.max_rtx_count =
config_.maxRetransmits ? *config_.maxRetransmits : -1;
send_params.max_rtx_ms =
config_.maxRetransmitTime ? *config_.maxRetransmitTime : -1;
send_params.sid = config_.id;
} else {
send_params.ssrc = send_ssrc_;
}
send_params.type = buffer.binary ? cricket::DMT_BINARY : cricket::DMT_TEXT;
cricket::SendDataResult send_result = cricket::SDR_SUCCESS;
bool success = provider_->SendData(send_params, buffer.data, &send_result);
if (success) {
++messages_sent_;
bytes_sent_ += buffer.size();
RTC_DCHECK(buffered_amount_ >= buffer.size());
buffered_amount_ -= buffer.size();
if (observer_ && buffer.size() > 0) {
observer_->OnBufferedAmountChange(buffer.size());
}
return true;
}
if (!IsSctpLike(data_channel_type_)) {
return false;
}
if (send_result == cricket::SDR_BLOCK) {
if (!queue_if_blocked || QueueSendDataMessage(buffer)) {
return false;
}
}
// Close the channel if the error is not SDR_BLOCK, or if queuing the
// message failed.
RTC_LOG(LS_ERROR) << "Closing the DataChannel due to a failure to send data, "
"send_result = "
<< send_result;
CloseAbruptly();
return false;
}
bool DataChannel::QueueSendDataMessage(const DataBuffer& buffer) {
size_t start_buffered_amount = queued_send_data_.byte_count();
if (start_buffered_amount + buffer.size() > kMaxQueuedSendDataBytes) {
RTC_LOG(LS_ERROR) << "Can't buffer any more data for the data channel.";
return false;
}
queued_send_data_.PushBack(std::make_unique<DataBuffer>(buffer));
return true;
}
void DataChannel::SendQueuedControlMessages() {
PacketQueue control_packets;
control_packets.Swap(&queued_control_data_);
while (!control_packets.Empty()) {
std::unique_ptr<DataBuffer> buf = control_packets.PopFront();
SendControlMessage(buf->data);
}
}
void DataChannel::QueueControlMessage(const rtc::CopyOnWriteBuffer& buffer) {
queued_control_data_.PushBack(std::make_unique<DataBuffer>(buffer, true));
}
bool DataChannel::SendControlMessage(const rtc::CopyOnWriteBuffer& buffer) {
bool is_open_message = handshake_state_ == kHandshakeShouldSendOpen;
RTC_DCHECK(IsSctpLike(data_channel_type_));
RTC_DCHECK(writable_);
RTC_DCHECK_GE(config_.id, 0);
RTC_DCHECK(!is_open_message || !config_.negotiated);
cricket::SendDataParams send_params;
send_params.sid = config_.id;
// Send data as ordered before we receive any message from the remote peer to
// make sure the remote peer will not receive any data before it receives the
// OPEN message.
send_params.ordered = config_.ordered || is_open_message;
send_params.type = cricket::DMT_CONTROL;
cricket::SendDataResult send_result = cricket::SDR_SUCCESS;
bool retval = provider_->SendData(send_params, buffer, &send_result);
if (retval) {
RTC_LOG(LS_INFO) << "Sent CONTROL message on channel " << config_.id;
if (handshake_state_ == kHandshakeShouldSendAck) {
handshake_state_ = kHandshakeReady;
} else if (handshake_state_ == kHandshakeShouldSendOpen) {
handshake_state_ = kHandshakeWaitingForAck;
}
} else if (send_result == cricket::SDR_BLOCK) {
QueueControlMessage(buffer);
} else {
RTC_LOG(LS_ERROR) << "Closing the DataChannel due to a failure to send"
" the CONTROL message, send_result = "
<< send_result;
CloseAbruptly();
}
return retval;
}
// static
void DataChannel::ResetInternalIdAllocatorForTesting(int new_value) {
g_unique_id = new_value;
}
} // namespace webrtc