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/*
* Copyright 2018 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.
*/
#ifndef P2P_BASE_REGATHERING_CONTROLLER_H_
#define P2P_BASE_REGATHERING_CONTROLLER_H_
#include <memory>
#include <optional>
#include "api/task_queue/pending_task_safety_flag.h"
#include "p2p/base/ice_transport_internal.h"
#include "p2p/base/p2p_constants.h"
#include "p2p/base/packet_transport_internal.h"
#include "p2p/base/port_allocator.h"
#include "rtc_base/network_route.h"
#include "rtc_base/third_party/sigslot/sigslot.h"
#include "rtc_base/thread.h"
namespace webrtc {
// Controls regathering of candidates for the ICE transport passed into it,
// reacting to signals like SignalWritableState, SignalNetworkRouteChange, etc.,
// using methods like GetStats to get additional information, and calling
// methods like RegatherOnFailedNetworks on the PortAllocatorSession when
// regathering is desired.
//
// "Regathering" is defined as gathering additional candidates within a single
// ICE generation (or in other words, PortAllocatorSession), and is possible
// when "continual gathering" is enabled. This may allow connectivity to be
// maintained and/or restored without a full ICE restart.
//
// Regathering will only begin after PortAllocationSession is set via
// set_allocator_session. This should be called any time the "active"
// PortAllocatorSession is changed (in other words, when an ICE restart occurs),
// so that candidates are gathered for the "current" ICE generation.
//
// All methods of BasicRegatheringController should be called on the same
// thread as the one passed to the constructor, and this thread should be the
// same one where PortAllocatorSession runs, which is also identical to the
// network thread of the ICE transport, as given by
// P2PTransportChannel::thread().
class BasicRegatheringController : public sigslot::has_slots<> {
public:
struct Config {
int regather_on_failed_networks_interval =
REGATHER_ON_FAILED_NETWORKS_INTERVAL;
};
BasicRegatheringController() = delete;
BasicRegatheringController(const Config& config,
IceTransportInternal* ice_transport,
Thread* thread);
~BasicRegatheringController() override;
// TODO(qingsi): Remove this method after implementing a new signal in
// P2PTransportChannel and reacting to that signal for the initial schedules
// of regathering.
void Start();
void set_allocator_session(PortAllocatorSession* allocator_session) {
allocator_session_ = allocator_session;
}
// Setting a different config of the regathering interval range on all
// networks cancels and reschedules the recurring schedules, if any, of
// regathering on all networks. The same applies to the change of the
// regathering interval on the failed networks. This rescheduling behavior is
// seperately defined for the two config parameters.
void SetConfig(const Config& config);
private:
// TODO(qingsi): Implement the following methods and use methods from the ICE
// transport like GetStats to get additional information for the decision
// making in regathering.
void OnIceTransportStateChanged(IceTransportInternal*) {}
void OnIceTransportWritableState(PacketTransportInternal*) {}
void OnIceTransportReceivingState(PacketTransportInternal*) {}
void OnIceTransportNetworkRouteChanged(std::optional<NetworkRoute>) {}
// Schedules delayed and repeated regathering of local candidates on failed
// networks, where the delay in milliseconds is given by the config. Each
// repetition is separated by the same delay. When scheduled, all previous
// schedules are canceled.
void ScheduleRecurringRegatheringOnFailedNetworks();
// Cancels regathering scheduled by ScheduleRecurringRegatheringOnAllNetworks.
void CancelScheduledRecurringRegatheringOnAllNetworks();
// We use a flag to be able to cancel pending regathering operations when
// the object goes out of scope or the config changes.
std::unique_ptr<ScopedTaskSafety> pending_regathering_;
Config config_;
IceTransportInternal* ice_transport_;
PortAllocatorSession* allocator_session_ = nullptr;
Thread* const thread_;
};
} // namespace webrtc
#endif // P2P_BASE_REGATHERING_CONTROLLER_H_
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