tdesktop/Telegram/SourceFiles/mtproto/special_config_request.cpp

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2017-06-26 17:38:16 +00:00
/*
This file is part of Telegram Desktop,
the official desktop application for the Telegram messaging service.
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For license and copyright information please follow this link:
https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
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*/
#include "mtproto/special_config_request.h"
#include "mtproto/rsa_public_key.h"
#include "mtproto/dc_options.h"
#include "mtproto/auth_key.h"
#include "base/unixtime.h"
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#include "base/openssl_help.h"
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extern "C" {
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#include <openssl/aes.h>
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} // extern "C"
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namespace MTP {
namespace {
struct DnsEntry {
QString data;
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crl::time TTL = 0;
};
constexpr auto kSendNextTimeout = crl::time(1000);
constexpr auto kMinTimeToLive = 10 * crl::time(1000);
constexpr auto kMaxTimeToLive = 300 * crl::time(1000);
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constexpr auto kPublicKey = str_const("\
-----BEGIN RSA PUBLIC KEY-----\n\
MIIBCgKCAQEAyr+18Rex2ohtVy8sroGPBwXD3DOoKCSpjDqYoXgCqB7ioln4eDCF\n\
fOBUlfXUEvM/fnKCpF46VkAftlb4VuPDeQSS/ZxZYEGqHaywlroVnXHIjgqoxiAd\n\
192xRGreuXIaUKmkwlM9JID9WS2jUsTpzQ91L8MEPLJ/4zrBwZua8W5fECwCCh2c\n\
9G5IzzBm+otMS/YKwmR1olzRCyEkyAEjXWqBI9Ftv5eG8m0VkBzOG655WIYdyV0H\n\
fDK/NWcvGqa0w/nriMD6mDjKOryamw0OP9QuYgMN0C9xMW9y8SmP4h92OAWodTYg\n\
Y1hZCxdv6cs5UnW9+PWvS+WIbkh+GaWYxwIDAQAB\n\
-----END RSA PUBLIC KEY-----\
");
constexpr auto kUserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
"AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.117 Safari/537.36";
const auto &DnsDomains() {
static auto result = std::vector<QString>{
qsl("google.com"),
qsl("www.google.com"),
qsl("google.ru"),
qsl("www.google.ru"),
};
return result;
}
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bool CheckPhoneByPrefixesRules(const QString &phone, const QString &rules) {
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const auto check = QString(phone).replace(
QRegularExpression("[^0-9]"),
QString());
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auto result = false;
for (const auto &prefix : rules.split(',')) {
if (prefix.isEmpty()) {
result = true;
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} else if (prefix[0] == '+' && check.startsWith(prefix.mid(1))) {
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result = true;
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} else if (prefix[0] == '-' && check.startsWith(prefix.mid(1))) {
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return false;
}
}
return result;
}
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QString GenerateRandomPadding() {
constexpr char kValid[] = "abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
auto result = QString();
const auto count = [&] {
constexpr auto kMinPadding = 13;
constexpr auto kMaxPadding = 128;
while (true) {
const auto result = 1 + (rand_value<uchar>() / 2);
Assert(result <= kMaxPadding);
if (result >= kMinPadding) {
return result;
}
}
}();
result.resize(count);
for (auto &ch : result) {
ch = kValid[rand_value<uchar>() % (sizeof(kValid) - 1)];
}
return result;
}
std::vector<DnsEntry> ParseDnsResponse(
const QByteArray &bytes,
std::optional<int> typeRestriction = std::nullopt) {
// Read and store to "result" all the data bytes from the response:
// { ..,
// "Answer": [
// { .., "data": "bytes1", "TTL": int, .. },
// { .., "data": "bytes2", "TTL": int, .. }
// ],
// .. }
auto error = QJsonParseError{ 0, QJsonParseError::NoError };
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const auto document = QJsonDocument::fromJson(bytes, &error);
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if (error.error != QJsonParseError::NoError) {
LOG(("Config Error: Failed to parse dns response JSON, error: %1"
).arg(error.errorString()));
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return {};
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} else if (!document.isObject()) {
LOG(("Config Error: Not an object received in dns response JSON."));
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return {};
}
const auto response = document.object();
const auto answerIt = response.find(qsl("Answer"));
if (answerIt == response.constEnd()) {
LOG(("Config Error: Could not find Answer in dns response JSON."));
return {};
} else if (!(*answerIt).isArray()) {
LOG(("Config Error: Not an array received "
"in Answer in dns response JSON."));
return {};
}
auto result = std::vector<DnsEntry>();
for (const auto elem : (*answerIt).toArray()) {
if (!elem.isObject()) {
LOG(("Config Error: Not an object found "
"in Answer array in dns response JSON."));
continue;
}
const auto object = elem.toObject();
if (typeRestriction) {
const auto typeIt = object.find(qsl("type"));
const auto type = int(std::round((*typeIt).toDouble()));
if (!(*typeIt).isDouble()) {
LOG(("Config Error: Not a number in type field "
"in Answer array in dns response JSON."));
continue;
} else if (type != *typeRestriction) {
continue;
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}
}
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const auto dataIt = object.find(qsl("data"));
if (dataIt == object.constEnd()) {
LOG(("Config Error: Could not find data "
"in Answer array entry in dns response JSON."));
continue;
} else if (!(*dataIt).isString()) {
LOG(("Config Error: Not a string data found "
"in Answer array entry in dns response JSON."));
continue;
}
const auto ttlIt = object.find(qsl("TTL"));
const auto ttl = (ttlIt != object.constEnd())
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? crl::time(std::round((*ttlIt).toDouble()))
: crl::time(0);
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result.push_back({ (*dataIt).toString(), ttl });
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}
return result;
}
QByteArray ConcatenateDnsTxtFields(const std::vector<DnsEntry> &response) {
auto entries = QMap<int, QString>();
for (const auto &entry : response) {
entries.insertMulti(INT_MAX - entry.data.size(), entry.data);
}
return QStringList(entries.values()).join(QString()).toLatin1();
}
[[nodiscard]] QDateTime ParseHttpDate(const QString &date) {
// Wed, 10 Jul 2019 14:33:38 GMT
static const auto expression = QRegularExpression(
R"(\w\w\w, (\d\d) (\w\w\w) (\d\d\d\d) (\d\d):(\d\d):(\d\d) GMT)");
const auto match = expression.match(date);
if (!match.hasMatch()) {
return QDateTime();
}
const auto number = [&](int index) {
return match.capturedRef(index).toInt();
};
const auto day = number(1);
const auto month = [&] {
static const auto months = {
"Jan",
"Feb",
"Mar",
"Apr",
"May",
"Jun",
"Jul",
"Aug",
"Sep",
"Oct",
"Nov",
"Dec"
};
const auto captured = match.capturedRef(2);
for (auto i = begin(months); i != end(months); ++i) {
if (captured == (*i)) {
return 1 + int(i - begin(months));
}
}
return 0;
}();
const auto year = number(3);
const auto hour = number(4);
const auto minute = number(5);
const auto second = number(6);
return QDateTime(
QDate(year, month, day),
QTime(hour, minute, second),
Qt::UTC);
}
} // namespace
ServiceWebRequest::ServiceWebRequest(not_null<QNetworkReply*> reply)
: reply(reply.get()) {
}
ServiceWebRequest::ServiceWebRequest(ServiceWebRequest &&other)
: reply(base::take(other.reply)) {
}
ServiceWebRequest &ServiceWebRequest::operator=(ServiceWebRequest &&other) {
if (reply != other.reply) {
destroy();
reply = base::take(other.reply);
}
return *this;
}
void ServiceWebRequest::destroy() {
if (const auto value = base::take(reply)) {
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value->disconnect(
value,
&QNetworkReply::finished,
nullptr,
nullptr);
value->abort();
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value->deleteLater();
}
}
ServiceWebRequest::~ServiceWebRequest() {
if (reply) {
reply->deleteLater();
}
}
SpecialConfigRequest::SpecialConfigRequest(
Fn<void(
DcId dcId,
const std::string &ip,
int port,
bytes::const_span secret)> callback,
Fn<void()> timeDoneCallback,
const QString &phone)
: _callback(std::move(callback))
, _timeDoneCallback(std::move(timeDoneCallback))
, _phone(phone) {
Expects((_callback == nullptr) != (_timeDoneCallback == nullptr));
_manager.setProxy(QNetworkProxy::NoProxy);
_attempts = {
//{ Type::App, qsl("software-download.microsoft.com") },
};
for (const auto &domain : DnsDomains()) {
_attempts.push_back({ Type::Dns, domain });
}
std::random_device rd;
ranges::shuffle(_attempts, std::mt19937(rd()));
sendNextRequest();
}
SpecialConfigRequest::SpecialConfigRequest(
Fn<void(
DcId dcId,
const std::string &ip,
int port,
bytes::const_span secret)> callback,
const QString &phone)
: SpecialConfigRequest(std::move(callback), nullptr, phone) {
}
SpecialConfigRequest::SpecialConfigRequest(Fn<void()> timeDoneCallback)
: SpecialConfigRequest(nullptr, std::move(timeDoneCallback), QString()) {
}
void SpecialConfigRequest::sendNextRequest() {
Expects(!_attempts.empty());
const auto attempt = _attempts.back();
_attempts.pop_back();
if (!_attempts.empty()) {
App::CallDelayed(kSendNextTimeout, this, [=] {
sendNextRequest();
});
}
performRequest(attempt);
}
void SpecialConfigRequest::performRequest(const Attempt &attempt) {
const auto type = attempt.type;
auto url = QUrl();
url.setScheme(qsl("https"));
url.setHost(attempt.domain);
auto request = QNetworkRequest();
switch (type) {
//case Type::App: {
// url.setPath(cTestMode()
// ? qsl("/testv2/config.txt")
// : qsl("/prodv2/config.txt"));
// request.setRawHeader("Host", "tcdnb.azureedge.net");
//} break;
case Type::Dns: {
url.setPath(qsl("/resolve"));
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url.setQuery(qsl("name=%1&type=ANY&random_padding=%2"
).arg(Global::TxtDomainString()
).arg(GenerateRandomPadding()));
request.setRawHeader("Host", "dns.google.com");
} break;
default: Unexpected("Type in SpecialConfigRequest::performRequest.");
}
request.setUrl(url);
request.setRawHeader("User-Agent", kUserAgent);
const auto reply = _requests.emplace_back(
_manager.get(request)
).reply;
connect(reply, &QNetworkReply::finished, this, [=] {
requestFinished(type, reply);
});
}
void SpecialConfigRequest::handleHeaderUnixtime(
not_null<QNetworkReply*> reply) {
if (reply->error() != QNetworkReply::NoError) {
return;
}
const auto date = QString::fromLatin1([&] {
for (const auto &pair : reply->rawHeaderPairs()) {
if (pair.first == "Date") {
return pair.second;
}
}
return QByteArray();
}());
if (date.isEmpty()) {
LOG(("Config Error: No 'Date' header received."));
return;
}
const auto parsed = ParseHttpDate(date);
if (!parsed.isValid()) {
LOG(("Config Error: Bad 'Date' header received: %1").arg(date));
return;
}
base::unixtime::http_update(parsed.toTime_t());
if (_timeDoneCallback) {
_timeDoneCallback();
}
}
void SpecialConfigRequest::requestFinished(
Type type,
not_null<QNetworkReply*> reply) {
handleHeaderUnixtime(reply);
const auto result = finalizeRequest(reply);
if (!_callback) {
return;
}
switch (type) {
//case Type::App: handleResponse(result); break;
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case Type::Dns: {
constexpr auto kTypeRestriction = 16; // TXT
handleResponse(ConcatenateDnsTxtFields(
ParseDnsResponse(result, kTypeRestriction)));
} break;
default: Unexpected("Type in SpecialConfigRequest::requestFinished.");
}
}
QByteArray SpecialConfigRequest::finalizeRequest(
not_null<QNetworkReply*> reply) {
if (reply->error() != QNetworkReply::NoError) {
LOG(("Config Error: Failed to get response, error: %2 (%3)"
).arg(reply->errorString()
).arg(reply->error()));
}
const auto result = reply->readAll();
const auto from = ranges::remove(
_requests,
reply,
[](const ServiceWebRequest &request) { return request.reply; });
_requests.erase(from, end(_requests));
return result;
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}
bool SpecialConfigRequest::decryptSimpleConfig(const QByteArray &bytes) {
auto cleanBytes = bytes;
auto removeFrom = std::remove_if(cleanBytes.begin(), cleanBytes.end(), [](char ch) {
auto isGoodBase64 = (ch == '+') || (ch == '=') || (ch == '/')
|| (ch >= 'a' && ch <= 'z')
|| (ch >= 'A' && ch <= 'Z')
|| (ch >= '0' && ch <= '9');
return !isGoodBase64;
});
if (removeFrom != cleanBytes.end()) {
cleanBytes.remove(removeFrom - cleanBytes.begin(), cleanBytes.end() - removeFrom);
}
constexpr auto kGoodSizeBase64 = 344;
if (cleanBytes.size() != kGoodSizeBase64) {
LOG(("Config Error: Bad data size %1 required %2").arg(cleanBytes.size()).arg(kGoodSizeBase64));
return false;
}
constexpr auto kGoodSizeData = 256;
auto decodedBytes = QByteArray::fromBase64(cleanBytes, QByteArray::Base64Encoding);
if (decodedBytes.size() != kGoodSizeData) {
LOG(("Config Error: Bad data size %1 required %2").arg(decodedBytes.size()).arg(kGoodSizeData));
return false;
}
auto publicKey = internal::RSAPublicKey(bytes::make_span(
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kPublicKey.c_str(),
kPublicKey.size()));
auto decrypted = publicKey.decrypt(bytes::make_span(decodedBytes));
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auto decryptedBytes = gsl::make_span(decrypted);
auto aesEncryptedBytes = decryptedBytes.subspan(CTRState::KeySize);
auto aesivec = bytes::make_vector(decryptedBytes.subspan(CTRState::KeySize - CTRState::IvecSize, CTRState::IvecSize));
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AES_KEY aeskey;
AES_set_decrypt_key(reinterpret_cast<const unsigned char*>(decryptedBytes.data()), CTRState::KeySize * CHAR_BIT, &aeskey);
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AES_cbc_encrypt(reinterpret_cast<const unsigned char*>(aesEncryptedBytes.data()), reinterpret_cast<unsigned char*>(aesEncryptedBytes.data()), aesEncryptedBytes.size(), &aeskey, reinterpret_cast<unsigned char*>(aesivec.data()), AES_DECRYPT);
constexpr auto kDigestSize = 16;
auto dataSize = aesEncryptedBytes.size() - kDigestSize;
auto data = aesEncryptedBytes.subspan(0, dataSize);
auto hash = openssl::Sha256(data);
if (bytes::compare(gsl::make_span(hash).subspan(0, kDigestSize), aesEncryptedBytes.subspan(dataSize)) != 0) {
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LOG(("Config Error: Bad digest."));
return false;
}
mtpBuffer buffer;
buffer.resize(data.size() / sizeof(mtpPrime));
bytes::copy(bytes::make_span(buffer), data);
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auto from = &*buffer.cbegin();
auto end = from + buffer.size();
auto realLength = *from++;
if (realLength <= 0 || realLength > dataSize || (realLength & 0x03)) {
LOG(("Config Error: Bad length %1.").arg(realLength));
return false;
}
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if (!_simpleConfig.read(from, end)) {
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LOG(("Config Error: Could not read configSimple."));
return false;
}
if ((end - from) * sizeof(mtpPrime) != (dataSize - realLength)) {
LOG(("Config Error: Bad read length %1, should be %2.").arg((end - from) * sizeof(mtpPrime)).arg(dataSize - realLength));
return false;
}
return true;
}
void SpecialConfigRequest::handleResponse(const QByteArray &bytes) {
if (!decryptSimpleConfig(bytes)) {
return;
}
Assert(_simpleConfig.type() == mtpc_help_configSimple);
const auto &config = _simpleConfig.c_help_configSimple();
const auto now = base::unixtime::http_now();
if (now > config.vexpires().v) {
LOG(("Config Error: "
"Bad date frame for simple config: %1-%2, our time is %3."
).arg(config.vdate().v
).arg(config.vexpires().v
).arg(now));
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return;
}
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if (config.vrules().v.empty()) {
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LOG(("Config Error: Empty simple config received."));
return;
}
for (const auto &rule : config.vrules().v) {
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Assert(rule.type() == mtpc_accessPointRule);
const auto &data = rule.c_accessPointRule();
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const auto phoneRules = qs(data.vphone_prefix_rules());
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if (!CheckPhoneByPrefixesRules(_phone, phoneRules)) {
continue;
}
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const auto dcId = data.vdc_id().v;
for (const auto &address : data.vips().v) {
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const auto parseIp = [](const MTPint &ipv4) {
const auto ip = *reinterpret_cast<const uint32*>(&ipv4.v);
return qsl("%1.%2.%3.%4"
).arg((ip >> 24) & 0xFF
).arg((ip >> 16) & 0xFF
).arg((ip >> 8) & 0xFF
).arg(ip & 0xFF).toStdString();
};
switch (address.type()) {
case mtpc_ipPort: {
const auto &fields = address.c_ipPort();
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_callback(dcId, parseIp(fields.vipv4()), fields.vport().v, {});
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} break;
case mtpc_ipPortSecret: {
const auto &fields = address.c_ipPortSecret();
_callback(
dcId,
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parseIp(fields.vipv4()),
fields.vport().v,
bytes::make_span(fields.vsecret().v));
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} break;
default: Unexpected("Type in simpleConfig ips.");
}
}
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}
}
DomainResolver::DomainResolver(Fn<void(
const QString &host,
const QStringList &ips,
crl::time expireAt)> callback)
: _callback(std::move(callback)) {
_manager.setProxy(QNetworkProxy::NoProxy);
}
void DomainResolver::resolve(const QString &domain) {
resolve({ domain, false });
resolve({ domain, true });
}
void DomainResolver::resolve(const AttemptKey &key) {
if (_attempts.find(key) != end(_attempts)) {
return;
} else if (_requests.find(key) != end(_requests)) {
return;
}
const auto i = _cache.find(key);
_lastTimestamp = crl::now();
if (i != end(_cache) && i->second.expireAt > _lastTimestamp) {
checkExpireAndPushResult(key.domain);
return;
}
auto hosts = DnsDomains();
std::random_device rd;
ranges::shuffle(hosts, std::mt19937(rd()));
_attempts.emplace(key, Attempts{ std::move(hosts) });
sendNextRequest(key);
}
void DomainResolver::checkExpireAndPushResult(const QString &domain) {
const auto ipv4 = _cache.find({ domain, false });
if (ipv4 == end(_cache) || ipv4->second.expireAt <= _lastTimestamp) {
return;
}
auto result = ipv4->second;
const auto ipv6 = _cache.find({ domain, true });
if (ipv6 != end(_cache) && ipv6->second.expireAt > _lastTimestamp) {
result.ips.append(ipv6->second.ips);
accumulate_min(result.expireAt, ipv6->second.expireAt);
}
InvokeQueued(this, [=] {
_callback(domain, result.ips, result.expireAt);
});
}
void DomainResolver::sendNextRequest(const AttemptKey &key) {
auto i = _attempts.find(key);
if (i == end(_attempts)) {
return;
}
auto &attempts = i->second;
auto &hosts = attempts.hosts;
const auto host = hosts.back();
hosts.pop_back();
if (!hosts.empty()) {
App::CallDelayed(kSendNextTimeout, &attempts.guard, [=] {
sendNextRequest(key);
});
}
performRequest(key, host);
}
void DomainResolver::performRequest(
const AttemptKey &key,
const QString &host) {
auto url = QUrl();
url.setScheme(qsl("https"));
url.setHost(host);
url.setPath(qsl("/resolve"));
url.setQuery(
qsl("name=%1&type=%2").arg(key.domain).arg(key.ipv6 ? 28 : 1));
auto request = QNetworkRequest();
request.setRawHeader("Host", "dns.google.com");
request.setUrl(url);
request.setRawHeader("User-Agent", kUserAgent);
const auto i = _requests.emplace(
key,
std::vector<ServiceWebRequest>()).first;
const auto reply = i->second.emplace_back(
_manager.get(request)
).reply;
connect(reply, &QNetworkReply::finished, this, [=] {
requestFinished(key, reply);
});
}
void DomainResolver::requestFinished(
const AttemptKey &key,
not_null<QNetworkReply*> reply) {
const auto result = finalizeRequest(key, reply);
const auto response = ParseDnsResponse(result);
if (response.empty()) {
return;
}
_requests.erase(key);
_attempts.erase(key);
auto entry = CacheEntry();
auto ttl = kMaxTimeToLive;
for (const auto &item : response) {
entry.ips.push_back(item.data);
accumulate_min(ttl, std::max(
item.TTL * crl::time(1000),
kMinTimeToLive));
}
_lastTimestamp = crl::now();
entry.expireAt = _lastTimestamp + ttl;
_cache[key] = std::move(entry);
checkExpireAndPushResult(key.domain);
}
QByteArray DomainResolver::finalizeRequest(
const AttemptKey &key,
not_null<QNetworkReply*> reply) {
if (reply->error() != QNetworkReply::NoError) {
LOG(("Resolve Error: Failed to get response, error: %2 (%3)"
).arg(reply->errorString()
).arg(reply->error()));
}
const auto result = reply->readAll();
const auto i = _requests.find(key);
if (i != end(_requests)) {
auto &requests = i->second;
const auto from = ranges::remove(
requests,
reply,
[](const ServiceWebRequest &request) { return request.reply; });
requests.erase(from, end(requests));
if (requests.empty()) {
_requests.erase(i);
}
}
return result;
}
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} // namespace MTP