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113 lines
3.5 KiB
113 lines
3.5 KiB
// Copyright 2019 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "discovery/mdns/mdns_probe.h"
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#include <utility>
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#include "discovery/mdns/mdns_random.h"
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#include "discovery/mdns/mdns_sender.h"
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#include "discovery/mdns/public/mdns_constants.h"
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#include "platform/api/task_runner.h"
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#include "platform/api/time.h"
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namespace openscreen {
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namespace discovery {
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MdnsProbe::MdnsProbe(DomainName target_name, IPAddress address)
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: target_name_(std::move(target_name)),
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address_(std::move(address)),
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address_record_(CreateAddressRecord(target_name_, address_)) {}
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MdnsProbe::~MdnsProbe() = default;
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MdnsProbeImpl::Observer::~Observer() = default;
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MdnsProbeImpl::MdnsProbeImpl(MdnsSender* sender,
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MdnsReceiver* receiver,
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MdnsRandom* random_delay,
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TaskRunner* task_runner,
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ClockNowFunctionPtr now_function,
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Observer* observer,
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DomainName target_name,
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IPAddress address)
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: MdnsProbe(std::move(target_name), std::move(address)),
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random_delay_(random_delay),
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task_runner_(task_runner),
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now_function_(now_function),
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alarm_(now_function_, task_runner_),
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sender_(sender),
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receiver_(receiver),
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observer_(observer) {
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OSP_DCHECK(sender_);
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OSP_DCHECK(receiver_);
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OSP_DCHECK(random_delay_);
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OSP_DCHECK(task_runner_);
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OSP_DCHECK(observer_);
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receiver_->AddResponseCallback(this);
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alarm_.ScheduleFromNow([this]() { ProbeOnce(); },
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random_delay_->GetInitialProbeDelay());
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}
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MdnsProbeImpl::~MdnsProbeImpl() {
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OSP_DCHECK(task_runner_->IsRunningOnTaskRunner());
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Stop();
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}
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void MdnsProbeImpl::ProbeOnce() {
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OSP_DCHECK(task_runner_->IsRunningOnTaskRunner());
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if (successful_probe_queries_++ < kProbeIterationCountBeforeSuccess) {
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// MdnsQuerier cannot be used, because probe queries cannot use the cache,
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// so instead directly send the query through the MdnsSender.
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MdnsMessage probe_query(CreateMessageId(), MessageType::Query);
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MdnsQuestion probe_question(target_name(), DnsType::kANY, DnsClass::kIN,
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ResponseType::kUnicast);
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probe_query.AddQuestion(probe_question);
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probe_query.AddAuthorityRecord(address_record());
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sender_->SendMulticast(probe_query);
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alarm_.ScheduleFromNow([this]() { ProbeOnce(); },
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kDelayBetweenProbeQueries);
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} else {
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Stop();
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observer_->OnProbeSuccess(this);
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}
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}
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void MdnsProbeImpl::Stop() {
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OSP_DCHECK(task_runner_->IsRunningOnTaskRunner());
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if (is_running_) {
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alarm_.Cancel();
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receiver_->RemoveResponseCallback(this);
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is_running_ = false;
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}
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}
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void MdnsProbeImpl::Postpone(std::chrono::seconds delay) {
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OSP_DCHECK(task_runner_->IsRunningOnTaskRunner());
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successful_probe_queries_ = 0;
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alarm_.Cancel();
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alarm_.ScheduleFromNow([this]() { ProbeOnce(); }, Clock::to_duration(delay));
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}
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void MdnsProbeImpl::OnMessageReceived(const MdnsMessage& message) {
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OSP_DCHECK(task_runner_->IsRunningOnTaskRunner());
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OSP_DCHECK(message.type() == MessageType::Response);
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for (const auto& record : message.answers()) {
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if (record.name() == target_name()) {
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Stop();
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observer_->OnProbeFailure(this);
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}
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}
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}
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} // namespace discovery
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} // namespace openscreen
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