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webrtc / src / c3771cc4d37f5573fe53b7c7cff295a4f0f9560f / . / webrtc / p2p / base / p2ptransportchannel.cc
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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 "webrtc/p2p/base/p2ptransportchannel.h"
#include <algorithm>
#include <iterator>
#include <set>
#include "webrtc/api/umametrics.h"
#include "webrtc/p2p/base/candidate.h"
#include "webrtc/p2p/base/candidatepairinterface.h"
#include "webrtc/p2p/base/common.h"
#include "webrtc/p2p/base/relayport.h" // For RELAY_PORT_TYPE.
#include "webrtc/p2p/base/stunport.h" // For STUN_PORT_TYPE.
#include "webrtc/rtc_base/checks.h"
#include "webrtc/rtc_base/crc32.h"
#include "webrtc/rtc_base/logging.h"
#include "webrtc/rtc_base/stringencode.h"
#include "webrtc/system_wrappers/include/field_trial.h"
namespace {
// messages for queuing up work for ourselves
enum {
MSG_SORT_AND_UPDATE_STATE = 1,
MSG_CHECK_AND_PING,
MSG_REGATHER_ON_FAILED_NETWORKS
};
// The minimum improvement in RTT that justifies a switch.
const int kMinImprovement = 10;
bool IsRelayRelay(const cricket::Connection* conn) {
return conn->local_candidate().type() == cricket::RELAY_PORT_TYPE &&
conn->remote_candidate().type() == cricket::RELAY_PORT_TYPE;
}
bool IsUdp(cricket::Connection* conn) {
return conn->local_candidate().relay_protocol() == cricket::UDP_PROTOCOL_NAME;
}
cricket::PortInterface::CandidateOrigin GetOrigin(cricket::PortInterface* port,
cricket::PortInterface* origin_port) {
if (!origin_port)
return cricket::PortInterface::ORIGIN_MESSAGE;
else if (port == origin_port)
return cricket::PortInterface::ORIGIN_THIS_PORT;
else
return cricket::PortInterface::ORIGIN_OTHER_PORT;
}
} // unnamed namespace
namespace cricket {
// When the socket is unwritable, we will use 10 Kbps (ignoring IP+UDP headers)
// for pinging. When the socket is writable, we will use only 1 Kbps because
// we don't want to degrade the quality on a modem. These numbers should work
// well on a 28.8K modem, which is the slowest connection on which the voice
// quality is reasonable at all.
static const int PING_PACKET_SIZE = 60 * 8;
// The next two ping intervals are at the channel level.
// STRONG_PING_INTERVAL (480ms) is applied when the selected connection is both
// writable and receiving.
const int STRONG_PING_INTERVAL = 1000 * PING_PACKET_SIZE / 1000;
// WEAK_PING_INTERVAL (48ms) is applied when the selected connection is either
// not writable or not receiving.
const int WEAK_PING_INTERVAL = 1000 * PING_PACKET_SIZE / 10000;
// The next two ping intervals are at the connection level.
// Writable connections are pinged at a faster rate while the connections are
// stabilizing or the channel is weak.
const int WEAK_OR_STABILIZING_WRITABLE_CONNECTION_PING_INTERVAL = 900; // ms
// Writable connections are pinged at a slower rate once they are stabilized and
// the channel is strongly connected.
const int STRONG_AND_STABLE_WRITABLE_CONNECTION_PING_INTERVAL = 2500; // ms
static const int MIN_CHECK_RECEIVING_INTERVAL = 50; // ms
static const int RECEIVING_SWITCHING_DELAY = 1000; // ms
// We periodically check if any existing networks do not have any connection
// and regather on those networks.
static const int DEFAULT_REGATHER_ON_FAILED_NETWORKS_INTERVAL = 5 * 60 * 1000;
static constexpr int DEFAULT_BACKUP_CONNECTION_PING_INTERVAL = 25 * 1000;
static constexpr int a_is_better = 1;
static constexpr int b_is_better = -1;
P2PTransportChannel::P2PTransportChannel(const std::string& transport_name,
int component,
PortAllocator* allocator)
: transport_name_(transport_name),
component_(component),
allocator_(allocator),
network_thread_(rtc::Thread::Current()),
incoming_only_(false),
error_(0),
sort_dirty_(false),
remote_ice_mode_(ICEMODE_FULL),
ice_role_(ICEROLE_UNKNOWN),
tiebreaker_(0),
gathering_state_(kIceGatheringNew),
check_receiving_interval_(MIN_CHECK_RECEIVING_INTERVAL * 5),
config_(MIN_CHECK_RECEIVING_INTERVAL * 50 /* receiving_timeout */,
DEFAULT_BACKUP_CONNECTION_PING_INTERVAL,
GATHER_ONCE /* continual_gathering_policy */,
false /* prioritize_most_likely_candidate_pairs */,
STRONG_AND_STABLE_WRITABLE_CONNECTION_PING_INTERVAL,
true /* presume_writable_when_fully_relayed */,
DEFAULT_REGATHER_ON_FAILED_NETWORKS_INTERVAL,
RECEIVING_SWITCHING_DELAY) {
uint32_t weak_ping_interval = ::strtoul(
webrtc::field_trial::FindFullName("WebRTC-StunInterPacketDelay").c_str(),
nullptr, 10);
if (weak_ping_interval) {
weak_ping_interval_ = static_cast<int>(weak_ping_interval);
}
}
P2PTransportChannel::~P2PTransportChannel() {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
}
// Add the allocator session to our list so that we know which sessions
// are still active.
void P2PTransportChannel::AddAllocatorSession(
std::unique_ptr<PortAllocatorSession> session) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
session->set_generation(static_cast<uint32_t>(allocator_sessions_.size()));
session->SignalPortReady.connect(this, &P2PTransportChannel::OnPortReady);
session->SignalPortsPruned.connect(this, &P2PTransportChannel::OnPortsPruned);
session->SignalCandidatesReady.connect(
this, &P2PTransportChannel::OnCandidatesReady);
session->SignalCandidatesRemoved.connect(
this, &P2PTransportChannel::OnCandidatesRemoved);
session->SignalCandidatesAllocationDone.connect(
this, &P2PTransportChannel::OnCandidatesAllocationDone);
if (!allocator_sessions_.empty()) {
allocator_session()->PruneAllPorts();
}
allocator_sessions_.push_back(std::move(session));
// We now only want to apply new candidates that we receive to the ports
// created by this new session because these are replacing those of the
// previous sessions.
PruneAllPorts();
}
void P2PTransportChannel::AddConnection(Connection* connection) {
connections_.push_back(connection);
unpinged_connections_.insert(connection);
connection->set_remote_ice_mode(remote_ice_mode_);
connection->set_receiving_timeout(config_.receiving_timeout);
connection->SignalReadPacket.connect(
this, &P2PTransportChannel::OnReadPacket);
connection->SignalReadyToSend.connect(
this, &P2PTransportChannel::OnReadyToSend);
connection->SignalStateChange.connect(
this, &P2PTransportChannel::OnConnectionStateChange);
connection->SignalDestroyed.connect(
this, &P2PTransportChannel::OnConnectionDestroyed);
connection->SignalNominated.connect(this, &P2PTransportChannel::OnNominated);
had_connection_ = true;
}
// Determines whether we should switch the selected connection to
// |new_connection| based the writable/receiving state, the nomination state,
// and the last data received time. This prevents the controlled side from
// switching the selected connection too frequently when the controlling side
// is doing aggressive nominations. The precedence of the connection switching
// criteria is as follows:
// i) write/receiving/connected states
// ii) For controlled side,
// a) nomination state,
// b) last data received time.
// iii) Lower cost / higher priority.
// iv) rtt.
// To further prevent switching to high-cost networks, does not switch to
// a high-cost connection if it is not receiving.
// TODO(honghaiz): Stop the aggressive nomination on the controlling side and
// implement the ice-renomination option.
bool P2PTransportChannel::ShouldSwitchSelectedConnection(
Connection* new_connection,
bool* missed_receiving_unchanged_threshold) const {
if (!ReadyToSend(new_connection) || selected_connection_ == new_connection) {
return false;
}
if (selected_connection_ == nullptr) {
return true;
}
// Do not switch to a connection that is not receiving if it has higher cost
// because it may be just spuriously better.
if (new_connection->ComputeNetworkCost() >
selected_connection_->ComputeNetworkCost() &&
!new_connection->receiving()) {
return false;
}
rtc::Optional<int64_t> receiving_unchanged_threshold(
rtc::TimeMillis() - config_.receiving_switching_delay.value_or(0));
int cmp = CompareConnections(selected_connection_, new_connection,
receiving_unchanged_threshold,
missed_receiving_unchanged_threshold);
if (cmp != 0) {
return cmp < 0;
}
// If everything else is the same, switch only if rtt has improved by
// a margin.
return new_connection->rtt() <= selected_connection_->rtt() - kMinImprovement;
}
bool P2PTransportChannel::MaybeSwitchSelectedConnection(
Connection* new_connection,
const std::string& reason) {
bool missed_receiving_unchanged_threshold = false;
if (ShouldSwitchSelectedConnection(new_connection,
&missed_receiving_unchanged_threshold)) {
LOG(LS_INFO) << "Switching selected connection due to " << reason;
SwitchSelectedConnection(new_connection);
return true;
}
if (missed_receiving_unchanged_threshold &&
config_.receiving_switching_delay) {
// If we do not switch to the connection because it missed the receiving
// threshold, the new connection is in a better receiving state than the
// currently selected connection. So we need to re-check whether it needs
// to be switched at a later time.
thread()->PostDelayed(RTC_FROM_HERE, *config_.receiving_switching_delay,
this, MSG_SORT_AND_UPDATE_STATE);
}
return false;
}
void P2PTransportChannel::SetIceRole(IceRole ice_role) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
if (ice_role_ != ice_role) {
ice_role_ = ice_role;
for (PortInterface* port : ports_) {
port->SetIceRole(ice_role);
}
// Update role on pruned ports as well, because they may still have
// connections alive that should be using the correct role.
for (PortInterface* port : pruned_ports_) {
port->SetIceRole(ice_role);
}
}
}
void P2PTransportChannel::SetIceTiebreaker(uint64_t tiebreaker) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
if (!ports_.empty() || !pruned_ports_.empty()) {
LOG(LS_ERROR)
<< "Attempt to change tiebreaker after Port has been allocated.";
return;
}
tiebreaker_ = tiebreaker;
}
IceTransportState P2PTransportChannel::GetState() const {
return state_;
}
rtc::Optional<int> P2PTransportChannel::GetRttEstimate() {
if (selected_connection_ != nullptr
&& selected_connection_->rtt_samples() > 0) {
return rtc::Optional<int>(selected_connection_->rtt());
} else {
return rtc::Optional<int>();
}
}
// A channel is considered ICE completed once there is at most one active
// connection per network and at least one active connection.
IceTransportState P2PTransportChannel::ComputeState() const {
if (!had_connection_) {
return IceTransportState::STATE_INIT;
}
std::vector<Connection*> active_connections;
for (Connection* connection : connections_) {
if (connection->active()) {
active_connections.push_back(connection);
}
}
if (active_connections.empty()) {
return IceTransportState::STATE_FAILED;
}
std::set<rtc::Network*> networks;
for (Connection* connection : active_connections) {
rtc::Network* network = connection->port()->Network();
if (networks.find(network) == networks.end()) {
networks.insert(network);
} else {
LOG_J(LS_VERBOSE, this) << "Ice not completed yet for this channel as "
<< network->ToString()
<< " has more than 1 connection.";
return IceTransportState::STATE_CONNECTING;
}
}
return IceTransportState::STATE_COMPLETED;
}
void P2PTransportChannel::SetIceParameters(const IceParameters& ice_params) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
LOG(LS_INFO) << "Set ICE ufrag: " << ice_params.ufrag
<< " pwd: " << ice_params.pwd << " on transport "
<< transport_name();
ice_parameters_ = ice_params;
// Note: Candidate gathering will restart when MaybeStartGathering is next
// called.
}
void P2PTransportChannel::SetRemoteIceParameters(
const IceParameters& ice_params) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
LOG(LS_INFO) << "Remote supports ICE renomination ? "
<< ice_params.renomination;
IceParameters* current_ice = remote_ice();
if (!current_ice || *current_ice != ice_params) {
// Keep the ICE credentials so that newer connections
// are prioritized over the older ones.
remote_ice_parameters_.push_back(ice_params);
}
// Update the pwd of remote candidate if needed.
for (RemoteCandidate& candidate : remote_candidates_) {
if (candidate.username() == ice_params.ufrag &&
candidate.password().empty()) {
candidate.set_password(ice_params.pwd);
}
}
// We need to update the credentials and generation for any peer reflexive
// candidates.
for (Connection* conn : connections_) {
conn->MaybeSetRemoteIceParametersAndGeneration(
ice_params, static_cast<int>(remote_ice_parameters_.size() - 1));
}
// Updating the remote ICE candidate generation could change the sort order.
RequestSortAndStateUpdate();
}
void P2PTransportChannel::SetRemoteIceMode(IceMode mode) {
remote_ice_mode_ = mode;
}
void P2PTransportChannel::SetIceConfig(const IceConfig& config) {
if (config_.continual_gathering_policy != config.continual_gathering_policy) {
if (!allocator_sessions_.empty()) {
LOG(LS_ERROR) << "Trying to change continual gathering policy "
<< "when gathering has already started!";
} else {
config_.continual_gathering_policy = config.continual_gathering_policy;
LOG(LS_INFO) << "Set continual_gathering_policy to "
<< config_.continual_gathering_policy;
}
}
if (config.backup_connection_ping_interval >= 0 &&
config_.backup_connection_ping_interval !=
config.backup_connection_ping_interval) {
config_.backup_connection_ping_interval =
config.backup_connection_ping_interval;
LOG(LS_INFO) << "Set backup connection ping interval to "
<< config_.backup_connection_ping_interval << " milliseconds.";
}
if (config.receiving_timeout >= 0 &&
config_.receiving_timeout != config.receiving_timeout) {
config_.receiving_timeout = config.receiving_timeout;
check_receiving_interval_ =
std::max(MIN_CHECK_RECEIVING_INTERVAL, config_.receiving_timeout / 10);
for (Connection* connection : connections_) {
connection->set_receiving_timeout(config_.receiving_timeout);
}
LOG(LS_INFO) << "Set ICE receiving timeout to " << config_.receiving_timeout
<< " milliseconds";
}
config_.prioritize_most_likely_candidate_pairs =
config.prioritize_most_likely_candidate_pairs;
LOG(LS_INFO) << "Set ping most likely connection to "
<< config_.prioritize_most_likely_candidate_pairs;
if (config.stable_writable_connection_ping_interval >= 0 &&
config_.stable_writable_connection_ping_interval !=
config.stable_writable_connection_ping_interval) {
config_.stable_writable_connection_ping_interval =
config.stable_writable_connection_ping_interval;
LOG(LS_INFO) << "Set stable_writable_connection_ping_interval to "
<< config_.stable_writable_connection_ping_interval;
}
if (config.presume_writable_when_fully_relayed !=
config_.presume_writable_when_fully_relayed) {
if (!connections_.empty()) {
LOG(LS_ERROR) << "Trying to change 'presume writable' "
<< "while connections already exist!";
} else {
config_.presume_writable_when_fully_relayed =
config.presume_writable_when_fully_relayed;
LOG(LS_INFO) << "Set presume writable when fully relayed to "
<< config_.presume_writable_when_fully_relayed;
}
}
if (config.regather_on_failed_networks_interval) {
config_.regather_on_failed_networks_interval =
config.regather_on_failed_networks_interval;
LOG(LS_INFO) << "Set regather_on_failed_networks_interval to "
<< *config_.regather_on_failed_networks_interval;
}
if (config.receiving_switching_delay) {
config_.receiving_switching_delay = config.receiving_switching_delay;
LOG(LS_INFO) << "Set receiving_switching_delay to"
<< *config_.receiving_switching_delay;
}
if (config_.default_nomination_mode != config.default_nomination_mode) {
config_.default_nomination_mode = config.default_nomination_mode;
LOG(LS_INFO) << "Set default nomination mode to "
<< static_cast<int>(config_.default_nomination_mode);
}
if (config_.ice_check_min_interval != config.ice_check_min_interval) {
config_.ice_check_min_interval = config.ice_check_min_interval;
LOG(LS_INFO) << "Set min ping interval to "
<< *config_.ice_check_min_interval;
}
}
const IceConfig& P2PTransportChannel::config() const {
return config_;
}
void P2PTransportChannel::SetMetricsObserver(
webrtc::MetricsObserverInterface* observer) {
metrics_observer_ = observer;
}
void P2PTransportChannel::MaybeStartGathering() {
if (ice_parameters_.ufrag.empty() || ice_parameters_.pwd.empty()) {
LOG(LS_ERROR) << "Cannot gather candidates because ICE parameters are empty"
<< " ufrag: " << ice_parameters_.ufrag
<< " pwd: " << ice_parameters_.pwd;
return;
}
// Start gathering if we never started before, or if an ICE restart occurred.
if (allocator_sessions_.empty() ||
IceCredentialsChanged(allocator_sessions_.back()->ice_ufrag(),
allocator_sessions_.back()->ice_pwd(),
ice_parameters_.ufrag, ice_parameters_.pwd)) {
if (gathering_state_ != kIceGatheringGathering) {
gathering_state_ = kIceGatheringGathering;
SignalGatheringState(this);
}
if (metrics_observer_ && !allocator_sessions_.empty()) {
IceRestartState state;
if (writable()) {
state = IceRestartState::CONNECTED;
} else if (IsGettingPorts()) {
state = IceRestartState::CONNECTING;
} else {
state = IceRestartState::DISCONNECTED;
}
metrics_observer_->IncrementEnumCounter(
webrtc::kEnumCounterIceRestart, static_cast<int>(state),
static_cast<int>(IceRestartState::MAX_VALUE));
}
// Time for a new allocator.
std::unique_ptr<PortAllocatorSession> pooled_session =
allocator_->TakePooledSession(transport_name(), component(),
ice_parameters_.ufrag,
ice_parameters_.pwd);
if (pooled_session) {
AddAllocatorSession(std::move(pooled_session));
PortAllocatorSession* raw_pooled_session =
allocator_sessions_.back().get();
// Process the pooled session's existing candidates/ports, if they exist.
OnCandidatesReady(raw_pooled_session,
raw_pooled_session->ReadyCandidates());
for (PortInterface* port : allocator_sessions_.back()->ReadyPorts()) {
OnPortReady(raw_pooled_session, port);
}
if (allocator_sessions_.back()->CandidatesAllocationDone()) {
OnCandidatesAllocationDone(raw_pooled_session);
}
} else {
AddAllocatorSession(allocator_->CreateSession(
transport_name(), component(), ice_parameters_.ufrag,
ice_parameters_.pwd));
allocator_sessions_.back()->StartGettingPorts();
}
}
}
// A new port is available, attempt to make connections for it
void P2PTransportChannel::OnPortReady(PortAllocatorSession *session,
PortInterface* port) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
// Set in-effect options on the new port
for (OptionMap::const_iterator it = options_.begin();
it != options_.end();
++it) {
int val = port->SetOption(it->first, it->second);
if (val < 0) {
LOG_J(LS_WARNING, port) << "SetOption(" << it->first
<< ", " << it->second
<< ") failed: " << port->GetError();
}
}
// Remember the ports and candidates, and signal that candidates are ready.
// The session will handle this, and send an initiate/accept/modify message
// if one is pending.
port->SetIceRole(ice_role_);
port->SetIceTiebreaker(tiebreaker_);
ports_.push_back(port);
port->SignalUnknownAddress.connect(
this, &P2PTransportChannel::OnUnknownAddress);
port->SignalDestroyed.connect(this, &P2PTransportChannel::OnPortDestroyed);
port->SignalRoleConflict.connect(
this, &P2PTransportChannel::OnRoleConflict);
port->SignalSentPacket.connect(this, &P2PTransportChannel::OnSentPacket);
// Attempt to create a connection from this new port to all of the remote
// candidates that we were given so far.
std::vector<RemoteCandidate>::iterator iter;
for (iter = remote_candidates_.begin(); iter != remote_candidates_.end();
++iter) {
CreateConnection(port, *iter, iter->origin_port());
}
SortConnectionsAndUpdateState();
}
// A new candidate is available, let listeners know
void P2PTransportChannel::OnCandidatesReady(
PortAllocatorSession* session,
const std::vector<Candidate>& candidates) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
for (size_t i = 0; i < candidates.size(); ++i) {
SignalCandidateGathered(this, candidates[i]);
}
}
void P2PTransportChannel::OnCandidatesAllocationDone(
PortAllocatorSession* session) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
if (config_.gather_continually()) {
LOG(LS_INFO) << "P2PTransportChannel: " << transport_name()
<< ", component " << component()
<< " gathering complete, but using continual "
<< "gathering so not changing gathering state.";
return;
}
gathering_state_ = kIceGatheringComplete;
LOG(LS_INFO) << "P2PTransportChannel: " << transport_name() << ", component "
<< component() << " gathering complete";
SignalGatheringState(this);
}
// Handle stun packets
void P2PTransportChannel::OnUnknownAddress(
PortInterface* port,
const rtc::SocketAddress& address, ProtocolType proto,
IceMessage* stun_msg, const std::string &remote_username,
bool port_muxed) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
// Port has received a valid stun packet from an address that no Connection
// is currently available for. See if we already have a candidate with the
// address. If it isn't we need to create new candidate for it.
const Candidate* candidate = nullptr;
for (const Candidate& c : remote_candidates_) {
if (c.username() == remote_username && c.address() == address &&
c.protocol() == ProtoToString(proto)) {
candidate = &c;
break;
}
}
uint32_t remote_generation = 0;
std::string remote_password;
// The STUN binding request may arrive after setRemoteDescription and before
// adding remote candidate, so we need to set the password to the shared
// password and set the generation if the user name matches.
const IceParameters* ice_param =
FindRemoteIceFromUfrag(remote_username, &remote_generation);
// Note: if not found, the remote_generation will still be 0.
if (ice_param != nullptr) {
remote_password = ice_param->pwd;
}
Candidate remote_candidate;
bool remote_candidate_is_new = (candidate == nullptr);
if (!remote_candidate_is_new) {
remote_candidate = *candidate;
} else {
// Create a new candidate with this address.
// The priority of the candidate is set to the PRIORITY attribute
// from the request.
const StunUInt32Attribute* priority_attr =
stun_msg->GetUInt32(STUN_ATTR_PRIORITY);
if (!priority_attr) {
LOG(LS_WARNING) << "P2PTransportChannel::OnUnknownAddress - "
<< "No STUN_ATTR_PRIORITY found in the "
<< "stun request message";
port->SendBindingErrorResponse(stun_msg, address, STUN_ERROR_BAD_REQUEST,
STUN_ERROR_REASON_BAD_REQUEST);
return;
}
int remote_candidate_priority = priority_attr->value();
uint16_t network_id = 0;
uint16_t network_cost = 0;
const StunUInt32Attribute* network_attr =
stun_msg->GetUInt32(STUN_ATTR_NETWORK_INFO);
if (network_attr) {
uint32_t network_info = network_attr->value();
network_id = static_cast<uint16_t>(network_info >> 16);
network_cost = static_cast<uint16_t>(network_info);
}
// RFC 5245
// If the source transport address of the request does not match any
// existing remote candidates, it represents a new peer reflexive remote
// candidate.
remote_candidate = Candidate(
component(), ProtoToString(proto), address, remote_candidate_priority,
remote_username, remote_password, PRFLX_PORT_TYPE, remote_generation,
"", network_id, network_cost);
// From RFC 5245, section-7.2.1.3:
// The foundation of the candidate is set to an arbitrary value, different
// from the foundation for all other remote candidates.
remote_candidate.set_foundation(
rtc::ToString<uint32_t>(rtc::ComputeCrc32(remote_candidate.id())));
}
// RFC5245, the agent constructs a pair whose local candidate is equal to
// the transport address on which the STUN request was received, and a
// remote candidate equal to the source transport address where the
// request came from.
// There shouldn't be an existing connection with this remote address.
// When ports are muxed, this channel might get multiple unknown address
// signals. In that case if the connection is already exists, we should
// simply ignore the signal otherwise send server error.
if (port->GetConnection(remote_candidate.address())) {
if (port_muxed) {
LOG(LS_INFO) << "Connection already exists for peer reflexive "
<< "candidate: " << remote_candidate.ToString();
return;
} else {
RTC_NOTREACHED();
port->SendBindingErrorResponse(stun_msg, address,
STUN_ERROR_SERVER_ERROR,
STUN_ERROR_REASON_SERVER_ERROR);
return;
}
}
Connection* connection =
port->CreateConnection(remote_candidate, PortInterface::ORIGIN_THIS_PORT);
if (!connection) {
// This could happen in some scenarios. For example, a TurnPort may have
// had a refresh request timeout, so it won't create connections.
port->SendBindingErrorResponse(stun_msg, address, STUN_ERROR_SERVER_ERROR,
STUN_ERROR_REASON_SERVER_ERROR);
return;
}
LOG(LS_INFO) << "Adding connection from "
<< (remote_candidate_is_new ? "peer reflexive" : "resurrected")
<< " candidate: " << remote_candidate.ToString();
AddConnection(connection);
connection->HandleBindingRequest(stun_msg);
// Update the list of connections since we just added another. We do this
// after sending the response since it could (in principle) delete the
// connection in question.
SortConnectionsAndUpdateState();
}
void P2PTransportChannel::OnRoleConflict(PortInterface* port) {
SignalRoleConflict(this); // STUN ping will be sent when SetRole is called
// from Transport.
}
const IceParameters* P2PTransportChannel::FindRemoteIceFromUfrag(
const std::string& ufrag,
uint32_t* generation) {
const auto& params = remote_ice_parameters_;
auto it = std::find_if(
params.rbegin(), params.rend(),
[ufrag](const IceParameters& param) { return param.ufrag == ufrag; });
if (it == params.rend()) {
// Not found.
return nullptr;
}
*generation = params.rend() - it - 1;
return &(*it);
}
void P2PTransportChannel::OnNominated(Connection* conn) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
RTC_DCHECK(ice_role_ == ICEROLE_CONTROLLED);
if (selected_connection_ == conn) {
return;
}
if (MaybeSwitchSelectedConnection(conn,
"nomination on the controlled side")) {
// Now that we have selected a connection, it is time to prune other
// connections and update the read/write state of the channel.
RequestSortAndStateUpdate();
} else {
LOG(LS_INFO)
<< "Not switching the selected connection on controlled side yet: "
<< conn->ToString();
}
}
void P2PTransportChannel::AddRemoteCandidate(const Candidate& candidate) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
uint32_t generation = GetRemoteCandidateGeneration(candidate);
// If a remote candidate with a previous generation arrives, drop it.
if (generation < remote_ice_generation()) {
LOG(LS_WARNING) << "Dropping a remote candidate because its ufrag "
<< candidate.username()
<< " indicates it was for a previous generation.";
return;
}
Candidate new_remote_candidate(candidate);
new_remote_candidate.set_generation(generation);
// ICE candidates don't need to have username and password set, but
// the code below this (specifically, ConnectionRequest::Prepare in
// port.cc) uses the remote candidates's username. So, we set it
// here.
if (remote_ice()) {
if (candidate.username().empty()) {
new_remote_candidate.set_username(remote_ice()->ufrag);
}
if (new_remote_candidate.username() == remote_ice()->ufrag) {
if (candidate.password().empty()) {
new_remote_candidate.set_password(remote_ice()->pwd);
}
} else {
// The candidate belongs to the next generation. Its pwd will be set
// when the new remote ICE credentials arrive.
LOG(LS_WARNING) << "A remote candidate arrives with an unknown ufrag: "
<< candidate.username();
}
}
// If this candidate matches what was thought to be a peer reflexive
// candidate, we need to update the candidate priority/etc.
for (Connection* conn : connections_) {
conn->MaybeUpdatePeerReflexiveCandidate(new_remote_candidate);
}
// Create connections to this remote candidate.
CreateConnections(new_remote_candidate, NULL);
// Resort the connections list, which may have new elements.
SortConnectionsAndUpdateState();
}
void P2PTransportChannel::RemoveRemoteCandidate(
const Candidate& cand_to_remove) {
auto iter =
std::remove_if(remote_candidates_.begin(), remote_candidates_.end(),
[cand_to_remove](const Candidate& candidate) {
return cand_to_remove.MatchesForRemoval(candidate);
});
if (iter != remote_candidates_.end()) {
LOG(LS_VERBOSE) << "Removed remote candidate " << cand_to_remove.ToString();
remote_candidates_.erase(iter, remote_candidates_.end());
}
}
// Creates connections from all of the ports that we care about to the given
// remote candidate. The return value is true if we created a connection from
// the origin port.
bool P2PTransportChannel::CreateConnections(const Candidate& remote_candidate,
PortInterface* origin_port) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
// If we've already seen the new remote candidate (in the current candidate
// generation), then we shouldn't try creating connections for it.
// We either already have a connection for it, or we previously created one
// and then later pruned it. If we don't return, the channel will again
// re-create any connections that were previously pruned, which will then
// immediately be re-pruned, churning the network for no purpose.
// This only applies to candidates received over signaling (i.e. origin_port
// is NULL).
if (!origin_port && IsDuplicateRemoteCandidate(remote_candidate)) {
// return true to indicate success, without creating any new connections.
return true;
}
// Add a new connection for this candidate to every port that allows such a
// connection (i.e., if they have compatible protocols) and that does not
// already have a connection to an equivalent candidate. We must be careful
// to make sure that the origin port is included, even if it was pruned,
// since that may be the only port that can create this connection.
bool created = false;
std::vector<PortInterface *>::reverse_iterator it;
for (it = ports_.rbegin(); it != ports_.rend(); ++it) {
if (CreateConnection(*it, remote_candidate, origin_port)) {
if (*it == origin_port)
created = true;
}
}
if ((origin_port != NULL) &&
std::find(ports_.begin(), ports_.end(), origin_port) == ports_.end()) {
if (CreateConnection(origin_port, remote_candidate, origin_port))
created = true;
}
// Remember this remote candidate so that we can add it to future ports.
RememberRemoteCandidate(remote_candidate, origin_port);
return created;
}
// Setup a connection object for the local and remote candidate combination.
// And then listen to connection object for changes.
bool P2PTransportChannel::CreateConnection(PortInterface* port,
const Candidate& remote_candidate,
PortInterface* origin_port) {
if (!port->SupportsProtocol(remote_candidate.protocol())) {
return false;
}
// Look for an existing connection with this remote address. If one is not
// found or it is found but the existing remote candidate has an older
// generation, then we can create a new connection for this address.
Connection* connection = port->GetConnection(remote_candidate.address());
if (connection == nullptr ||
connection->remote_candidate().generation() <
remote_candidate.generation()) {
// Don't create a connection if this is a candidate we received in a
// message and we are not allowed to make outgoing connections.
PortInterface::CandidateOrigin origin = GetOrigin(port, origin_port);
if (origin == PortInterface::ORIGIN_MESSAGE && incoming_only_) {
return false;
}
Connection* connection = port->CreateConnection(remote_candidate, origin);
if (!connection) {
return false;
}
AddConnection(connection);
LOG_J(LS_INFO, this) << "Created connection with origin=" << origin << ", ("
<< connections_.size() << " total)";
return true;
}
// No new connection was created.
// It is not legal to try to change any of the parameters of an existing
// connection; however, the other side can send a duplicate candidate.
if (!remote_candidate.IsEquivalent(connection->remote_candidate())) {
LOG(INFO) << "Attempt to change a remote candidate."
<< " Existing remote candidate: "
<< connection->remote_candidate().ToString()
<< "New remote candidate: " << remote_candidate.ToString();
}
return false;
}
bool P2PTransportChannel::FindConnection(Connection* connection) const {
std::vector<Connection*>::const_iterator citer =
std::find(connections_.begin(), connections_.end(), connection);
return citer != connections_.end();
}
uint32_t P2PTransportChannel::GetRemoteCandidateGeneration(
const Candidate& candidate) {
// If the candidate has a ufrag, use it to find the generation.
if (!candidate.username().empty()) {
uint32_t generation = 0;
if (!FindRemoteIceFromUfrag(candidate.username(), &generation)) {
// If the ufrag is not found, assume the next/future generation.
generation = static_cast<uint32_t>(remote_ice_parameters_.size());
}
return generation;
}
// If candidate generation is set, use that.
if (candidate.generation() > 0) {
return candidate.generation();
}
// Otherwise, assume the generation from remote ice parameters.
return remote_ice_generation();
}
// Check if remote candidate is already cached.
bool P2PTransportChannel::IsDuplicateRemoteCandidate(
const Candidate& candidate) {
for (size_t i = 0; i < remote_candidates_.size(); ++i) {
if (remote_candidates_[i].IsEquivalent(candidate)) {
return true;
}
}
return false;
}
// Maintain our remote candidate list, adding this new remote one.
void P2PTransportChannel::RememberRemoteCandidate(
const Candidate& remote_candidate, PortInterface* origin_port) {
// Remove any candidates whose generation is older than this one. The
// presence of a new generation indicates that the old ones are not useful.
size_t i = 0;
while (i < remote_candidates_.size()) {
if (remote_candidates_[i].generation() < remote_candidate.generation()) {
LOG(INFO) << "Pruning candidate from old generation: "
<< remote_candidates_[i].address().ToSensitiveString();
remote_candidates_.erase(remote_candidates_.begin() + i);
} else {
i += 1;
}
}
// Make sure this candidate is not a duplicate.
if (IsDuplicateRemoteCandidate(remote_candidate)) {
LOG(INFO) << "Duplicate candidate: " << remote_candidate.ToString();
return;
}
// Try this candidate for all future ports.
remote_candidates_.push_back(RemoteCandidate(remote_candidate, origin_port));
}
// Set options on ourselves is simply setting options on all of our available
// port objects.
int P2PTransportChannel::SetOption(rtc::Socket::Option opt, int value) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
OptionMap::iterator it = options_.find(opt);
if (it == options_.end()) {
options_.insert(std::make_pair(opt, value));
} else if (it->second == value) {
return 0;
} else {
it->second = value;
}
for (PortInterface* port : ports_) {
int val = port->SetOption(opt, value);
if (val < 0) {
// Because this also occurs deferred, probably no point in reporting an
// error
LOG(WARNING) << "SetOption(" << opt << ", " << value
<< ") failed: " << port->GetError();
}
}
return 0;
}
bool P2PTransportChannel::GetOption(rtc::Socket::Option opt, int* value) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
const auto& found = options_.find(opt);
if (found == options_.end()) {
return false;
}
*value = found->second;
return true;
}
// Send data to the other side, using our selected connection.
int P2PTransportChannel::SendPacket(const char *data, size_t len,
const rtc::PacketOptions& options,
int flags) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
if (flags != 0) {
error_ = EINVAL;
return -1;
}
// If we don't think the connection is working yet, return ENOTCONN
// instead of sending a packet that will probably be dropped.
if (!ReadyToSend(selected_connection_)) {
error_ = ENOTCONN;
return -1;
}
last_sent_packet_id_ = options.packet_id;
int sent = selected_connection_->Send(data, len, options);
if (sent <= 0) {
RTC_DCHECK(sent < 0);
error_ = selected_connection_->GetError();
}
return sent;
}
bool P2PTransportChannel::GetStats(ConnectionInfos *infos) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
// Gather connection infos.
infos->clear();
for (Connection* connection : connections_) {
ConnectionInfo info = connection->stats();
info.best_connection = (selected_connection_ == connection);
infos->push_back(std::move(info));
connection->set_reported(true);
}
return true;
}
rtc::DiffServCodePoint P2PTransportChannel::DefaultDscpValue() const {
OptionMap::const_iterator it = options_.find(rtc::Socket::OPT_DSCP);
if (it == options_.end()) {
return rtc::DSCP_NO_CHANGE;
}
return static_cast<rtc::DiffServCodePoint> (it->second);
}
// Monitor connection states.
void P2PTransportChannel::UpdateConnectionStates() {
int64_t now = rtc::TimeMillis();
// We need to copy the list of connections since some may delete themselves
// when we call UpdateState.
for (Connection* c : connections_) {
c->UpdateState(now);
}
}
// Prepare for best candidate sorting.
void P2PTransportChannel::RequestSortAndStateUpdate() {
if (!sort_dirty_) {
network_thread_->Post(RTC_FROM_HERE, this, MSG_SORT_AND_UPDATE_STATE);
sort_dirty_ = true;
}
}
void P2PTransportChannel::MaybeStartPinging() {
if (started_pinging_) {
return;
}
int64_t now = rtc::TimeMillis();
if (std::any_of(
connections_.begin(), connections_.end(),
[this, now](const Connection* c) { return IsPingable(c, now); })) {
LOG_J(LS_INFO, this) << "Have a pingable connection for the first time; "
<< "starting to ping.";
thread()->Post(RTC_FROM_HERE, this, MSG_CHECK_AND_PING);
thread()->PostDelayed(RTC_FROM_HERE,
*config_.regather_on_failed_networks_interval, this,
MSG_REGATHER_ON_FAILED_NETWORKS);
started_pinging_ = true;
}
}
// Compare two connections based on their writing, receiving, and connected
// states.
int P2PTransportChannel::CompareConnectionStates(
const Connection* a,
const Connection* b,
rtc::Optional<int64_t> receiving_unchanged_threshold,
bool* missed_receiving_unchanged_threshold) const {
// First, prefer a connection that's writable or presumed writable over
// one that's not writable.
bool a_writable = a->writable() || PresumedWritable(a);
bool b_writable = b->writable() || PresumedWritable(b);
if (a_writable && !b_writable) {
return a_is_better;
}
if (!a_writable && b_writable) {
return b_is_better;
}
// Sort based on write-state. Better states have lower values.
if (a->write_state() < b->write_state()) {
return a_is_better;
}
if (b->write_state() < a->write_state()) {
return b_is_better;
}
// We prefer a receiving connection to a non-receiving, higher-priority
// connection when sorting connections and choosing which connection to
// switch to.
if (a->receiving() && !b->receiving()) {
return a_is_better;
}
if (!a->receiving() && b->receiving()) {
if (!receiving_unchanged_threshold ||
(a->receiving_unchanged_since() <= *receiving_unchanged_threshold &&
b->receiving_unchanged_since() <= *receiving_unchanged_threshold)) {
return b_is_better;
}
*missed_receiving_unchanged_threshold = true;
}
// WARNING: Some complexity here about TCP reconnecting.
// When a TCP connection fails because of a TCP socket disconnecting, the
// active side of the connection will attempt to reconnect for 5 seconds while
// pretending to be writable (the connection is not set to the unwritable
// state). On the passive side, the connection also remains writable even
// though it is disconnected, and a new connection is created when the active
// side connects. At that point, there are two TCP connections on the passive
// side: 1. the old, disconnected one that is pretending to be writable, and
// 2. the new, connected one that is maybe not yet writable. For purposes of
// pruning, pinging, and selecting the selected connection, we want to treat
// the new connection as "better" than the old one. We could add a method
// called something like Connection::ImReallyBadEvenThoughImWritable, but that
// is equivalent to the existing Connection::connected(), which we already
// have. So, in code throughout this file, we'll check whether the connection
// is connected() or not, and if it is not, treat it as "worse" than a
// connected one, even though it's writable. In the code below, we're doing
// so to make sure we treat a new writable connection as better than an old
// disconnected connection.
// In the case where we reconnect TCP connections, the original best
// connection is disconnected without changing to WRITE_TIMEOUT. In this case,
// the new connection, when it becomes writable, should have higher priority.
if (a->write_state() == Connection::STATE_WRITABLE &&
b->write_state() == Connection::STATE_WRITABLE) {
if (a->connected() && !b->connected()) {
return a_is_better;
}
if (!a->connected() && b->connected()) {
return b_is_better;
}
}
return 0;
}
// Compares two connections based only on the candidate and network information.
// Returns positive if |a| is better than |b|.
int P2PTransportChannel::CompareConnectionCandidates(
const Connection* a,
const Connection* b) const {
// Prefer lower network cost.
uint32_t a_cost = a->ComputeNetworkCost();
uint32_t b_cost = b->ComputeNetworkCost();
// Smaller cost is better.
if (a_cost < b_cost) {
return a_is_better;
}
if (a_cost > b_cost) {
return b_is_better;
}
// Compare connection priority. Lower values get sorted last.
if (a->priority() > b->priority()) {
return a_is_better;
}
if (a->priority() < b->priority()) {
return b_is_better;
}
// If we're still tied at this point, prefer a younger generation.
// (Younger generation means a larger generation number).
return (a->remote_candidate().generation() + a->port()->generation()) -
(b->remote_candidate().generation() + b->port()->generation());
}
int P2PTransportChannel::CompareConnections(
const Connection* a,
const Connection* b,
rtc::Optional<int64_t> receiving_unchanged_threshold,
bool* missed_receiving_unchanged_threshold) const {
RTC_CHECK(a != nullptr);
RTC_CHECK(b != nullptr);
// We prefer to switch to a writable and receiving connection over a
// non-writable or non-receiving connection, even if the latter has
// been nominated by the controlling side.
int state_cmp = CompareConnectionStates(a, b, receiving_unchanged_threshold,
missed_receiving_unchanged_threshold);
if (state_cmp != 0) {
return state_cmp;
}
if (ice_role_ == ICEROLE_CONTROLLED) {
// Compare the connections based on the nomination states and the last data
// received time if this is on the controlled side.
if (a->remote_nomination() > b->remote_nomination()) {
return a_is_better;
}
if (a->remote_nomination() < b->remote_nomination()) {
return b_is_better;
}
if (a->last_data_received() > b->last_data_received()) {
return a_is_better;
}
if (a->last_data_received() < b->last_data_received()) {
return b_is_better;
}
}
// Compare the network cost and priority.
return CompareConnectionCandidates(a, b);
}
bool P2PTransportChannel::PresumedWritable(const Connection* conn) const {
return (conn->write_state() == Connection::STATE_WRITE_INIT &&
config_.presume_writable_when_fully_relayed &&
conn->local_candidate().type() == RELAY_PORT_TYPE &&
(conn->remote_candidate().type() == RELAY_PORT_TYPE ||
conn->remote_candidate().type() == PRFLX_PORT_TYPE));
}
// Sort the available connections to find the best one. We also monitor
// the number of available connections and the current state.
void P2PTransportChannel::SortConnectionsAndUpdateState() {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
// Make sure the connection states are up-to-date since this affects how they
// will be sorted.
UpdateConnectionStates();
// Any changes after this point will require a re-sort.
sort_dirty_ = false;
// Find the best alternative connection by sorting. It is important to note
// that amongst equal preference, writable connections, this will choose the
// one whose estimated latency is lowest. So it is the only one that we
// need to consider switching to.
// TODO(honghaiz): Don't sort; Just use std::max_element in the right places.
std::stable_sort(connections_.begin(), connections_.end(),
[this](const Connection* a, const Connection* b) {
int cmp = CompareConnections(
a, b, rtc::Optional<int64_t>(), nullptr);
if (cmp != 0) {
return cmp > 0;
}
// Otherwise, sort based on latency estimate.
return a->rtt() < b->rtt();
});
LOG(LS_VERBOSE) << "Sorting " << connections_.size()
<< " available connections:";
for (size_t i = 0; i < connections_.size(); ++i) {
LOG(LS_VERBOSE) << connections_[i]->ToString();
}
Connection* top_connection =
(connections_.size() > 0) ? connections_[0] : nullptr;
// If necessary, switch to the new choice. Note that |top_connection| doesn't
// have to be writable to become the selected connection although it will
// have higher priority if it is writable.
MaybeSwitchSelectedConnection(top_connection, "sorting");
// The controlled side can prune only if the selected connection has been
// nominated because otherwise it may prune the connection that will be
// selected by the controlling side.
// TODO(honghaiz): This is not enough to prevent a connection from being
// pruned too early because with aggressive nomination, the controlling side
// will nominate every connection until it becomes writable.
if (ice_role_ == ICEROLE_CONTROLLING ||
(selected_connection_ && selected_connection_->nominated())) {
PruneConnections();
}
// Check if all connections are timedout.
bool all_connections_timedout = true;
for (size_t i = 0; i < connections_.size(); ++i) {
if (connections_[i]->write_state() != Connection::STATE_WRITE_TIMEOUT) {
all_connections_timedout = false;
break;
}
}
// Now update the writable state of the channel with the information we have
// so far.
if (all_connections_timedout) {
HandleAllTimedOut();
}
// Update the state of this channel.
UpdateState();
// Also possibly start pinging.
// We could start pinging if:
// * The first connection was created.
// * ICE credentials were provided.
// * A TCP connection became connected.
MaybeStartPinging();
}
std::map<rtc::Network*, Connection*>
P2PTransportChannel::GetBestConnectionByNetwork() const {
// |connections_| has been sorted, so the first one in the list on a given
// network is the best connection on the network, except that the selected
// connection is always the best connection on the network.
std::map<rtc::Network*, Connection*> best_connection_by_network;
if (selected_connection_) {
best_connection_by_network[selected_connection_->port()->Network()] =
selected_connection_;
}
// TODO(honghaiz): Need to update this if |connections_| are not sorted.
for (Connection* conn : connections_) {
rtc::Network* network = conn->port()->Network();
// This only inserts when the network does not exist in the map.
best_connection_by_network.insert(std::make_pair(network, conn));
}
return best_connection_by_network;
}
std::vector<Connection*>
P2PTransportChannel::GetBestWritableConnectionPerNetwork() const {
std::vector<Connection*> connections;
for (auto kv : GetBestConnectionByNetwork()) {
Connection* conn = kv.second;
if (conn->writable() && conn->connected()) {
connections.push_back(conn);
}
}
return connections;
}
void P2PTransportChannel::PruneConnections() {
// We can prune any connection for which there is a connected, writable
// connection on the same network with better or equal priority. We leave
// those with better priority just in case they become writable later (at
// which point, we would prune out the current selected connection). We leave
// connections on other networks because they may not be using the same
// resources and they may represent very distinct paths over which we can
// switch. If |best_conn_on_network| is not connected, we may be reconnecting
// a TCP connection and should not prune connections in this network.
// See the big comment in CompareConnectionStates.
//
// An exception is made for connections on an "any address" network, meaning
// not bound to any specific network interface. We don't want to keep one of
// these alive as a backup, since it could be using the same network
// interface as the higher-priority, selected candidate pair.
auto best_connection_by_network = GetBestConnectionByNetwork();
for (Connection* conn : connections_) {
Connection* best_conn = selected_connection_;
if (!rtc::IPIsAny(conn->port()->Network()->ip())) {
// If the connection is bound to a specific network interface (not an
// "any address" network), compare it against the best connection for
// that network interface rather than the best connection overall. This
// ensures that at least one connection per network will be left
// unpruned.
best_conn = best_connection_by_network[conn->port()->Network()];
}
// Do not prune connections if the connection being compared against is
// weak. Otherwise, it may delete connections prematurely.
if (best_conn && conn != best_conn && !best_conn->weak() &&
CompareConnectionCandidates(best_conn, conn) >= 0) {
conn->Prune();
}
}
}
// Change the selected connection, and let listeners know.
void P2PTransportChannel::SwitchSelectedConnection(Connection* conn) {
// Note: if conn is NULL, the previous |selected_connection_| has been
// destroyed, so don't use it.
Connection* old_selected_connection = selected_connection_;
selected_connection_ = conn;
if (selected_connection_) {
++nomination_;
if (old_selected_connection) {
LOG_J(LS_INFO, this) << "Previous selected connection: "
<< old_selected_connection->ToString();
}
LOG_J(LS_INFO, this) << "New selected connection: "
<< selected_connection_->ToString();
SignalRouteChange(this, selected_connection_->remote_candidate());
// This is a temporary, but safe fix to webrtc issue 5705.
// TODO(honghaiz): Make all ENOTCONN error routed through the transport
// channel so that it knows whether the media channel is allowed to
// send; then it will only signal ready-to-send if the media channel
// has been disallowed to send.
if (selected_connection_->writable() ||
PresumedWritable(selected_connection_)) {
SignalReadyToSend(this);
}
} else {
LOG_J(LS_INFO, this) << "No selected connection";
}
SignalSelectedCandidatePairChanged(this, selected_connection_,
last_sent_packet_id_,
ReadyToSend(selected_connection_));
}
// Warning: UpdateState should eventually be called whenever a connection
// is added, deleted, or the write state of any connection changes so that the
// transport controller will get the up-to-date channel state. However it
// should not be called too often; in the case that multiple connection states
// change, it should be called after all the connection states have changed. For
// example, we call this at the end of SortConnectionsAndUpdateState.
void P2PTransportChannel::UpdateState() {
IceTransportState state = ComputeState();
if (state_ != state) {
LOG_J(LS_INFO, this) << "Transport channel state changed from "
<< static_cast<int>(state_) << " to "
<< static_cast<int>(state);
// Check that the requested transition is allowed. Note that
// P2PTransportChannel does not (yet) implement a direct mapping of the ICE
// states from the standard; the difference is covered by
// TransportController and PeerConnection.
switch (state_) {
case IceTransportState::STATE_INIT:
// TODO(deadbeef): Once we implement end-of-candidates signaling,
// we shouldn't go from INIT to COMPLETED.
RTC_DCHECK(state == IceTransportState::STATE_CONNECTING ||
state == IceTransportState::STATE_COMPLETED);
break;
case IceTransportState::STATE_CONNECTING:
RTC_DCHECK(state == IceTransportState::STATE_COMPLETED ||
state == IceTransportState::STATE_FAILED);
break;
case IceTransportState::STATE_COMPLETED:
// TODO(deadbeef): Once we implement end-of-candidates signaling,
// we shouldn't go from COMPLETED to CONNECTING.
// Though we *can* go from COMPlETED to FAILED, if consent expires.
RTC_DCHECK(state == IceTransportState::STATE_CONNECTING ||
state == IceTransportState::STATE_FAILED);
break;
case IceTransportState::STATE_FAILED:
// TODO(deadbeef): Once we implement end-of-candidates signaling,
// we shouldn't go from FAILED to CONNECTING or COMPLETED.
RTC_DCHECK(state == IceTransportState::STATE_CONNECTING ||
state == IceTransportState::STATE_COMPLETED);
break;
default:
RTC_NOTREACHED();
break;
}
state_ = state;
SignalStateChanged(this);
}
// If our selected connection is "presumed writable" (TURN-TURN with no
// CreatePermission required), act like we're already writable to the upper
// layers, so they can start media quicker.
bool writable =
selected_connection_ && (selected_connection_->writable() ||
PresumedWritable(selected_connection_));
set_writable(writable);
bool receiving = false;
for (const Connection* connection : connections_) {
if (connection->receiving()) {
receiving = true;
break;
}
}
set_receiving(receiving);
}
void P2PTransportChannel::MaybeStopPortAllocatorSessions() {
if (!IsGettingPorts()) {
return;
}
for (const auto& session : allocator_sessions_) {
if (session->IsStopped()) {
continue;
}
// If gathering continually, keep the last session running so that
// it can gather candidates if the networks change.
if (config_.gather_continually() && session == allocator_sessions_.back()) {
session->ClearGettingPorts();
} else {
session->StopGettingPorts();
}
}
}
// If all connections timed out, delete them all.
void P2PTransportChannel::HandleAllTimedOut() {
for (Connection* connection : connections_) {
connection->Destroy();
}
}
bool P2PTransportChannel::weak() const {
return !selected_connection_ || selected_connection_->weak();
}
bool P2PTransportChannel::ReadyToSend(Connection* connection) const {
// Note that we allow sending on an unreliable connection, because it's
// possible that it became unreliable simply due to bad chance.
// So this shouldn't prevent attempting to send media.
return connection != nullptr &&
(connection->writable() ||
connection->write_state() == Connection::STATE_WRITE_UNRELIABLE ||
PresumedWritable(connection));
}
// Handle any queued up requests
void P2PTransportChannel::OnMessage(rtc::Message *pmsg) {
switch (pmsg->message_id) {
case MSG_SORT_AND_UPDATE_STATE:
SortConnectionsAndUpdateState();
break;
case MSG_CHECK_AND_PING:
OnCheckAndPing();
break;
case MSG_REGATHER_ON_FAILED_NETWORKS:
OnRegatherOnFailedNetworks();
break;
default:
RTC_NOTREACHED();
break;
}
}
// Handle queued up check-and-ping request
void P2PTransportChannel::OnCheckAndPing() {
// Make sure the states of the connections are up-to-date (since this affects
// which ones are pingable).
UpdateConnectionStates();
// When the selected connection is not receiving or not writable, or any
// active connection has not been pinged enough times, use the weak ping
// interval.
bool need_more_pings_at_weak_interval = std::any_of(
connections_.begin(), connections_.end(), [](Connection* conn) {
return conn->active() &&
conn->num_pings_sent() < MIN_PINGS_AT_WEAK_PING_INTERVAL;
});
int ping_interval = (weak() || need_more_pings_at_weak_interval)
? weak_ping_interval()
: strong_ping_interval();
if (rtc::TimeMillis() >= last_ping_sent_ms_ + ping_interval) {
Connection* conn = FindNextPingableConnection();
if (conn) {
PingConnection(conn);
MarkConnectionPinged(conn);
}
}
int delay = std::min(ping_interval, check_receiving_interval_);
thread()->PostDelayed(RTC_FROM_HERE, delay, this, MSG_CHECK_AND_PING);
}
// A connection is considered a backup connection if the channel state
// is completed, the connection is not the selected connection and it is active.
bool P2PTransportChannel::IsBackupConnection(const Connection* conn) const {
return state_ == IceTransportState::STATE_COMPLETED &&
conn != selected_connection_ && conn->active();
}
// Is the connection in a state for us to even consider pinging the other side?
// We consider a connection pingable even if it's not connected because that's
// how a TCP connection is kicked into reconnecting on the active side.
bool P2PTransportChannel::IsPingable(const Connection* conn,
int64_t now) const {
const Candidate& remote = conn->remote_candidate();
// We should never get this far with an empty remote ufrag.
RTC_DCHECK(!remote.username().empty());
if (remote.username().empty() || remote.password().empty()) {
// If we don't have an ICE ufrag and pwd, there's no way we can ping.
return false;
}
// A failed connection will not be pinged.
if (conn->state() == IceCandidatePairState::FAILED) {
return false;
}
// An never connected connection cannot be written to at all, so pinging is
// out of the question. However, if it has become WRITABLE, it is in the
// reconnecting state so ping is needed.
if (!conn->connected() && !conn->writable()) {
return false;
}
// If the channel is weakly connected, ping all connections.
if (weak()) {
return true;
}
// Always ping active connections regardless whether the channel is completed
// or not, but backup connections are pinged at a slower rate.
if (IsBackupConnection(conn)) {
return conn->rtt_samples() == 0 ||
(now >= conn->last_ping_response_received() +
config_.backup_connection_ping_interval);
}
// Don't ping inactive non-backup connections.
if (!conn->active()) {
return false;
}
// Do ping unwritable, active connections.
if (!conn->writable()) {
return true;
}
// Ping writable, active connections if it's been long enough since the last
// ping.
return WritableConnectionPastPingInterval(conn, now);
}
bool P2PTransportChannel::WritableConnectionPastPingInterval(
const Connection* conn,
int64_t now) const {
int interval = CalculateActiveWritablePingInterval(conn, now);
return conn->last_ping_sent() + interval <= now;
}
int P2PTransportChannel::CalculateActiveWritablePingInterval(
const Connection* conn,
int64_t now) const {
// Ping each connection at a higher rate at least
// MIN_PINGS_AT_WEAK_PING_INTERVAL times.
if (conn->num_pings_sent() < MIN_PINGS_AT_WEAK_PING_INTERVAL) {
return weak_ping_interval();
}
int stable_interval = config_.stable_writable_connection_ping_interval;
int weak_or_stablizing_interval = std::min(
stable_interval, WEAK_OR_STABILIZING_WRITABLE_CONNECTION_PING_INTERVAL);
// If the channel is weak or the connection is not stable yet, use the
// weak_or_stablizing_interval.
return (!weak() && conn->stable(now)) ? stable_interval
: weak_or_stablizing_interval;
}
// Returns the next pingable connection to ping.
Connection* P2PTransportChannel::FindNextPingableConnection() {
int64_t now = rtc::TimeMillis();
// Rule 1: Selected connection takes priority over non-selected ones.
if (selected_connection_ && selected_connection_->connected() &&
selected_connection_->writable() &&
WritableConnectionPastPingInterval(selected_connection_, now)) {
return selected_connection_;
}
// Rule 2: If the channel is weak, we need to find a new writable and
// receiving connection, probably on a different network. If there are lots of
// connections, it may take several seconds between two pings for every
// non-selected connection. This will cause the receiving state of those
// connections to be false, and thus they won't be selected. This is
// problematic for network fail-over. We want to make sure at least one
// connection per network is pinged frequently enough in order for it to be
// selectable. So we prioritize one connection per network.
// Rule 2.1: Among such connections, pick the one with the earliest
// last-ping-sent time.
if (weak()) {
auto selectable_connections = GetBestWritableConnectionPerNetwork();
std::vector<Connection*> pingable_selectable_connections;
std::copy_if(selectable_connections.begin(), selectable_connections.end(),
std::back_inserter(pingable_selectable_connections),
[this, now](Connection* conn) {
return WritableConnectionPastPingInterval(conn, now);
});
auto iter = std::min_element(pingable_selectable_connections.begin(),
pingable_selectable_connections.end(),
[](Connection* conn1, Connection* conn2) {
return conn1->last_ping_sent() <
conn2->last_ping_sent();
});
if (iter != pingable_selectable_connections.end()) {
return *iter;
}
}
// Rule 3: Triggered checks have priority over non-triggered connections.
// Rule 3.1: Among triggered checks, oldest takes precedence.
Connection* oldest_triggered_check =
FindOldestConnectionNeedingTriggeredCheck(now);
if (oldest_triggered_check) {
return oldest_triggered_check;
}
// Rule 4: Unpinged connections have priority over pinged ones.
RTC_CHECK(connections_.size() ==
pinged_connections_.size() + unpinged_connections_.size());
// If there are unpinged and pingable connections, only ping those.
// Otherwise, treat everything as unpinged.
// TODO(honghaiz): Instead of adding two separate vectors, we can add a state
// "pinged" to filter out unpinged connections.
if (std::find_if(unpinged_connections_.begin(), unpinged_connections_.end(),
[this, now](Connection* conn) {
return this->IsPingable(conn, now);
}) == unpinged_connections_.end()) {
unpinged_connections_.insert(pinged_connections_.begin(),
pinged_connections_.end());
pinged_connections_.clear();
}
// Among un-pinged pingable connections, "more pingable" takes precedence.
std::vector<Connection*> pingable_connections;
std::copy_if(unpinged_connections_.begin(), unpinged_connections_.end(),
std::back_inserter(pingable_connections),
[this, now](Connection* conn) { return IsPingable(conn, now); });
auto iter =
std::max_element(pingable_connections.begin(), pingable_connections.end(),
[this](Connection* conn1, Connection* conn2) {
return MorePingable(conn1, conn2) == conn2;
});
if (iter != pingable_connections.end()) {
return *iter;
}
return nullptr;
}
void P2PTransportChannel::MarkConnectionPinged(Connection* conn) {
if (conn && pinged_connections_.insert(conn).second) {
unpinged_connections_.erase(conn);
}
}
// Apart from sending ping from |conn| this method also updates
// |use_candidate_attr| and |nomination| flags. One of the flags is set to
// nominate |conn| if this channel is in CONTROLLING.
void P2PTransportChannel::PingConnection(Connection* conn) {
bool use_candidate_attr = false;
uint32_t nomination = 0;
if (ice_role_ == ICEROLE_CONTROLLING) {
bool renomination_supported = ice_parameters_.renomination &&
!remote_ice_parameters_.empty() &&
remote_ice_parameters_.back().renomination;
if (renomination_supported) {
nomination = GetNominationAttr(conn);
} else {
use_candidate_attr =
GetUseCandidateAttr(conn, config_.default_nomination_mode);
}
}
conn->set_nomination(nomination);
conn->set_use_candidate_attr(use_candidate_attr);
last_ping_sent_ms_ = rtc::TimeMillis();
conn->Ping(last_ping_sent_ms_);
}
uint32_t P2PTransportChannel::GetNominationAttr(Connection* conn) const {
return (conn == selected_connection_) ? nomination_ : 0;
}
// Nominate a connection based on the NominationMode.
bool P2PTransportChannel::GetUseCandidateAttr(Connection* conn,
NominationMode mode) const {
switch (mode) {
case NominationMode::REGULAR:
// TODO(honghaiz): Implement regular nomination.
return false;
case NominationMode::AGGRESSIVE:
if (remote_ice_mode_ == ICEMODE_LITE) {
return GetUseCandidateAttr(conn, NominationMode::REGULAR);
}
return true;
case NominationMode::SEMI_AGGRESSIVE: {
// Nominate if
// a) Remote is in FULL ICE AND
// a.1) |conn| is the selected connection OR
// a.2) there is no selected connection OR
// a.3) the selected connection is unwritable OR
// a.4) |conn| has higher priority than selected_connection.
// b) Remote is in LITE ICE AND
// b.1) |conn| is the selected_connection AND
// b.2) |conn| is writable.
bool selected = conn == selected_connection_;
if (remote_ice_mode_ == ICEMODE_LITE) {
return selected && conn->writable();
}
bool better_than_selected =
!selected_connection_ || !selected_connection_->writable() ||
CompareConnectionCandidates(selected_connection_, conn) < 0;
return selected || better_than_selected;
}
default:
RTC_NOTREACHED();
return false;
}
}
// When a connection's state changes, we need to figure out who to use as
// the selected connection again. It could have become usable, or become
// unusable.
void P2PTransportChannel::OnConnectionStateChange(Connection* connection) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
// May stop the allocator session when at least one connection becomes
// strongly connected after starting to get ports and the local candidate of
// the connection is at the latest generation. It is not enough to check
// that the connection becomes weakly connected because the connection may be
// changing from (writable, receiving) to (writable, not receiving).
bool strongly_connected = !connection->weak();
bool latest_generation = connection->local_candidate().generation() >=
allocator_session()->generation();
if (strongly_connected && latest_generation) {
MaybeStopPortAllocatorSessions();
}
// We have to unroll the stack before doing this because we may be changing
// the state of connections while sorting.
RequestSortAndStateUpdate();
}
// When a connection is removed, edit it out, and then update our best
// connection.
void P2PTransportChannel::OnConnectionDestroyed(Connection* connection) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
// Note: the previous selected_connection_ may be destroyed by now, so don't
// use it.
// Remove this connection from the list.
std::vector<Connection*>::iterator iter =
std::find(connections_.begin(), connections_.end(), connection);
RTC_DCHECK(iter != connections_.end());
pinged_connections_.erase(*iter);
unpinged_connections_.erase(*iter);
connections_.erase(iter);
LOG_J(LS_INFO, this) << "Removed connection " << std::hex << connection
<< std::dec << " (" << connections_.size()
<< " remaining)";
// If this is currently the selected connection, then we need to pick a new
// one. The call to SortConnectionsAndUpdateState will pick a new one. It
// looks at the current selected connection in order to avoid switching
// between fairly similar ones. Since this connection is no longer an option,
// we can just set selected to nullptr and re-choose a best assuming that
// there was no selected connection.
if (selected_connection_ == connection) {
LOG(LS_INFO) << "Selected connection destroyed. Will choose a new one.";
SwitchSelectedConnection(nullptr);
RequestSortAndStateUpdate();
} else {
// If a non-selected connection was destroyed, we don't need to re-sort but
// we do need to update state, because we could be switching to "failed" or
// "completed".
UpdateState();
}
}
// When a port is destroyed, remove it from our list of ports to use for
// connection attempts.
void P2PTransportChannel::OnPortDestroyed(PortInterface* port) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
ports_.erase(std::remove(ports_.begin(), ports_.end(), port), ports_.end());
pruned_ports_.erase(
std::remove(pruned_ports_.begin(), pruned_ports_.end(), port),
pruned_ports_.end());
LOG(INFO) << "Removed port because it is destroyed: " << ports_.size()
<< " remaining";
}
void P2PTransportChannel::OnPortsPruned(
PortAllocatorSession* session,
const std::vector<PortInterface*>& ports) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
for (PortInterface* port : ports) {
if (PrunePort(port)) {
LOG(INFO) << "Removed port: " << port->ToString() << " " << ports_.size()
<< " remaining";
}
}
}
void P2PTransportChannel::OnCandidatesRemoved(
PortAllocatorSession* session,
const std::vector<Candidate>& candidates) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
// Do not signal candidate removals if continual gathering is not enabled, or
// if this is not the last session because an ICE restart would have signaled
// the remote side to remove all candidates in previous sessions.
if (!config_.gather_continually() || session != allocator_session()) {
return;
}
std::vector<Candidate> candidates_to_remove;
for (Candidate candidate : candidates) {
candidate.set_transport_name(transport_name());
candidates_to_remove.push_back(candidate);
}
SignalCandidatesRemoved(this, candidates_to_remove);
}
void P2PTransportChannel::OnRegatherOnFailedNetworks() {
// Only re-gather when the current session is in the CLEARED state (i.e., not
// running or stopped). It is only possible to enter this state when we gather
// continually, so there is an implicit check on continual gathering here.
if (!allocator_sessions_.empty() && allocator_session()->IsCleared()) {
allocator_session()->RegatherOnFailedNetworks();
}
thread()->PostDelayed(RTC_FROM_HERE,
*config_.regather_on_failed_networks_interval, this,
MSG_REGATHER_ON_FAILED_NETWORKS);
}
void P2PTransportChannel::PruneAllPorts() {
pruned_ports_.insert(pruned_ports_.end(), ports_.begin(), ports_.end());
ports_.clear();
}
bool P2PTransportChannel::PrunePort(PortInterface* port) {
auto it = std::find(ports_.begin(), ports_.end(), port);
// Don't need to do anything if the port has been deleted from the port list.
if (it == ports_.end()) {
return false;
}
ports_.erase(it);
pruned_ports_.push_back(port);
return true;
}
// We data is available, let listeners know
void P2PTransportChannel::OnReadPacket(Connection* connection,
const char* data,
size_t len,
const rtc::PacketTime& packet_time) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
// Do not deliver, if packet doesn't belong to the correct transport channel.
if (!FindConnection(connection))
return;
// Let the client know of an incoming packet
SignalReadPacket(this, data, len, packet_time, 0);
// May need to switch the sending connection based on the receiving media path
// if this is the controlled side.
if (ice_role_ == ICEROLE_CONTROLLED) {
MaybeSwitchSelectedConnection(connection, "data received");
}
}
void P2PTransportChannel::OnSentPacket(const rtc::SentPacket& sent_packet) {
RTC_DCHECK(network_thread_ == rtc::Thread::Current());
SignalSentPacket(this, sent_packet);
}
void P2PTransportChannel::OnReadyToSend(Connection* connection) {
if (connection == selected_connection_ && writable()) {
SignalReadyToSend(this);
}
}
// Find "triggered checks". We ping first those connections that have
// received a ping but have not sent a ping since receiving it
// (last_ping_received > last_ping_sent). But we shouldn't do
// triggered checks if the connection is already writable.
Connection* P2PTransportChannel::FindOldestConnectionNeedingTriggeredCheck(
int64_t now) {
Connection* oldest_needing_triggered_check = nullptr;
for (auto conn : connections_) {
if (!IsPingable(conn, now)) {
continue;
}
bool needs_triggered_check =
(!conn->writable() &&
conn->last_ping_received() > conn->last_ping_sent());
if (needs_triggered_check &&
(!oldest_needing_triggered_check ||
(conn->last_ping_received() <
oldest_needing_triggered_check->last_ping_received()))) {
oldest_needing_triggered_check = conn;
}
}
if (oldest_needing_triggered_check) {
LOG(LS_INFO) << "Selecting connection for triggered check: "
<< oldest_needing_triggered_check->ToString();
}
return oldest_needing_triggered_check;
}
Connection* P2PTransportChannel::MostLikelyToWork(Connection* conn1,
Connection* conn2) {
bool rr1 = IsRelayRelay(conn1);
bool rr2 = IsRelayRelay(conn2);
if (rr1 && !rr2) {
return conn1;
} else if (rr2 && !rr1) {
return conn2;
} else if (rr1 && rr2) {
bool udp1 = IsUdp(conn1);
bool udp2 = IsUdp(conn2);
if (udp1 && !udp2) {
return conn1;
} else if (udp2 && udp1) {
return conn2;
}
}
return nullptr;
}
Connection* P2PTransportChannel::LeastRecentlyPinged(Connection* conn1,
Connection* conn2) {
if (conn1->last_ping_sent() < conn2->last_ping_sent()) {
return conn1;
}
if (conn1->last_ping_sent() > conn2->last_ping_sent()) {
return conn2;
}
return nullptr;
}
Connection* P2PTransportChannel::MorePingable(Connection* conn1,
Connection* conn2) {
RTC_DCHECK(conn1 != conn2);
if (config_.prioritize_most_likely_candidate_pairs) {
Connection* most_likely_to_work_conn = MostLikelyToWork(conn1, conn2);
if (most_likely_to_work_conn) {
return most_likely_to_work_conn;
}
}
Connection* least_recently_pinged_conn = LeastRecentlyPinged(conn1, conn2);
if (least_recently_pinged_conn) {
return least_recently_pinged_conn;
}
// During the initial state when nothing has been pinged yet, return the first
// one in the ordered |connections_|.
return *(std::find_if(connections_.begin(), connections_.end(),
[conn1, conn2](Connection* conn) {
return conn == conn1 || conn == conn2;
}));
}
void P2PTransportChannel::set_writable(bool writable) {
if (writable_ == writable) {
return;
}
LOG_J(LS_VERBOSE, this) << "set_writable from:" << writable_ << " to "
<< writable;
writable_ = writable;
if (writable_) {
SignalReadyToSend(this);
}
SignalWritableState(this);
}
void P2PTransportChannel::set_receiving(bool receiving) {
if (receiving_ == receiving) {
return;
}
receiving_ = receiving;
SignalReceivingState(this);
}
} // namespace cricket