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/**
* Copyright (c) 2019, The Android Open Source Project
*
* 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 "dns_metrics_listener.h"
#include <thread>
#include <android-base/chrono_utils.h>
#include <android-base/format.h>
namespace android {
namespace net {
namespace metrics {
using android::base::ScopedLockAssertion;
using std::chrono::milliseconds;
constexpr milliseconds kRetryIntervalMs{20};
constexpr milliseconds kEventTimeoutMs{5000};
bool DnsMetricsListener::DnsEvent::operator==(const DnsMetricsListener::DnsEvent& o) const {
return std::tie(netId, eventType, returnCode, hostname, ipAddresses, ipAddressesCount) ==
std::tie(o.netId, o.eventType, o.returnCode, o.hostname, o.ipAddresses,
o.ipAddressesCount);
}
std::ostream& operator<<(std::ostream& os, const DnsMetricsListener::DnsEvent& data) {
return os << fmt::format("[{}, {}, {}, {}, [{}], {}]", data.netId, data.eventType,
data.returnCode, data.hostname, fmt::join(data.ipAddresses, ", "),
data.ipAddressesCount);
}
::ndk::ScopedAStatus DnsMetricsListener::onNat64PrefixEvent(int32_t netId, bool added,
const std::string& prefixString,
int32_t /*prefixLength*/) {
std::lock_guard lock(mMutex);
mUnexpectedNat64PrefixUpdates++;
if (netId == mNetId) mNat64Prefix = added ? prefixString : "";
return ::ndk::ScopedAStatus::ok();
}
::ndk::ScopedAStatus DnsMetricsListener::onPrivateDnsValidationEvent(
int32_t netId, const std::string& ipAddress, const std::string& /*hostname*/,
bool validated) {
{
std::lock_guard lock(mMutex);
// keep updating the server to have latest validation status.
mValidationRecords.insert_or_assign({netId, ipAddress}, validated);
}
mCv.notify_one();
return ::ndk::ScopedAStatus::ok();
}
::ndk::ScopedAStatus DnsMetricsListener::onDnsEvent(int32_t netId, int32_t eventType,
int32_t returnCode, int32_t /*latencyMs*/,
const std::string& hostname,
const std::vector<std::string>& ipAddresses,
int32_t ipAddressesCount, int32_t /*uid*/) {
std::lock_guard lock(mMutex);
if (netId == mNetId) {
mDnsEventRecords.push(
{netId, eventType, returnCode, hostname, ipAddresses, ipAddressesCount});
}
return ::ndk::ScopedAStatus::ok();
}
bool DnsMetricsListener::waitForNat64Prefix(ExpectNat64PrefixStatus status, milliseconds timeout) {
android::base::Timer t;
while (t.duration() < timeout) {
{
std::lock_guard lock(mMutex);
if ((status == EXPECT_FOUND && !mNat64Prefix.empty()) ||
(status == EXPECT_NOT_FOUND && mNat64Prefix.empty())) {
mUnexpectedNat64PrefixUpdates--;
return true;
}
}
std::this_thread::sleep_for(kRetryIntervalMs);
}
return false;
}
bool DnsMetricsListener::waitForPrivateDnsValidation(const std::string& serverAddr,
const bool validated) {
const auto now = std::chrono::steady_clock::now();
std::unique_lock lock(mMutex);
ScopedLockAssertion assume_lock(mMutex);
// onPrivateDnsValidationEvent() might already be invoked. Search for the record first.
do {
if (findAndRemoveValidationRecord({mNetId, serverAddr}, validated)) return true;
} while (mCv.wait_until(lock, now + kEventTimeoutMs) != std::cv_status::timeout);
// Timeout.
return false;
}
bool DnsMetricsListener::findAndRemoveValidationRecord(const ServerKey& key, const bool value) {
auto it = mValidationRecords.find(key);
if (it != mValidationRecords.end() && it->second == value) {
mValidationRecords.erase(it);
return true;
}
return false;
}
std::optional<DnsMetricsListener::DnsEvent> DnsMetricsListener::popDnsEvent() {
// Wait until the queue is not empty or timeout.
android::base::Timer t;
while (t.duration() < milliseconds{1000}) {
{
std::lock_guard lock(mMutex);
if (!mDnsEventRecords.empty()) break;
}
std::this_thread::sleep_for(kRetryIntervalMs);
}
std::lock_guard lock(mMutex);
if (mDnsEventRecords.empty()) return std::nullopt;
auto ret = mDnsEventRecords.front();
mDnsEventRecords.pop();
return ret;
}
} // namespace metrics
} // namespace net
} // namespace android
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