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/*
* Copyright (c) 2017-2021 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <protocols/rtc/probe_handler.h>
#include <protocols/rtc/rtc_consts.h>
namespace transport {
namespace protocol {
namespace rtc {
ProbeHandler::ProbeHandler(SendProbeCallback &&send_callback,
asio::io_service &io_service)
: probe_interval_(0),
max_probes_(0),
sent_probes_(0),
probe_timer_(std::make_unique<asio::steady_timer>(io_service)),
rand_eng_((std::random_device())()),
distr_(MIN_RTT_PROBE_SEQ, MAX_RTT_PROBE_SEQ),
send_probe_callback_(std::move(send_callback)) {}
ProbeHandler::~ProbeHandler() {}
uint64_t ProbeHandler::getRtt(uint32_t seq) {
auto it = pending_probes_.find(seq);
if (it == pending_probes_.end()) return 0;
uint64_t now = std::chrono::duration_cast<std::chrono::milliseconds>(
std::chrono::steady_clock::now().time_since_epoch())
.count();
uint64_t rtt = now - it->second;
if (rtt < 1) rtt = 1;
pending_probes_.erase(it);
return rtt;
}
void ProbeHandler::setProbes(uint32_t probe_interval, uint32_t max_probes) {
stopProbes();
probe_interval_ = probe_interval;
max_probes_ = max_probes;
}
void ProbeHandler::stopProbes() {
probe_interval_ = 0;
max_probes_ = 0;
sent_probes_ = 0;
probe_timer_->cancel();
}
void ProbeHandler::sendProbes() {
if (probe_interval_ == 0) return;
if (max_probes_ != 0 && sent_probes_ >= max_probes_) return;
uint64_t now = std::chrono::duration_cast<std::chrono::milliseconds>(
std::chrono::steady_clock::now().time_since_epoch())
.count();
uint32_t seq = distr_(rand_eng_);
pending_probes_.insert(std::pair<uint32_t, uint64_t>(seq, now));
send_probe_callback_(seq);
sent_probes_++;
// clean up
// a probe may get lost. if the pending_probes_ size becomes bigger than
// MAX_PENDING_PROBES remove all the probes older than a seconds
if (pending_probes_.size() > MAX_PENDING_PROBES) {
for (auto it = pending_probes_.begin(); it != pending_probes_.end();) {
if ((now - it->second) > 1000)
it = pending_probes_.erase(it);
else
it++;
}
}
if (probe_interval_ == 0) return;
std::weak_ptr<ProbeHandler> self(shared_from_this());
probe_timer_->expires_from_now(std::chrono::microseconds(probe_interval_));
probe_timer_->async_wait([self](std::error_code ec) {
if (ec) return;
if (auto s = self.lock()) {
s->sendProbes();
}
});
}
} // namespace rtc
} // namespace protocol
} // namespace transport
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