tdlight/tdnet/td/net/GetHostByNameActor.cpp

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//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2023
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "td/net/GetHostByNameActor.h"
#include "td/net/HttpQuery.h"
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#include "td/net/SslCtx.h"
#include "td/net/Wget.h"
#include "td/utils/common.h"
#include "td/utils/JsonBuilder.h"
#include "td/utils/logging.h"
#include "td/utils/misc.h"
#include "td/utils/Slice.h"
#include "td/utils/SliceBuilder.h"
#include "td/utils/Time.h"
namespace td {
namespace detail {
class GoogleDnsResolver final : public Actor {
public:
GoogleDnsResolver(std::string host, bool prefer_ipv6, Promise<IPAddress> promise)
: host_(std::move(host)), prefer_ipv6_(prefer_ipv6), promise_(std::move(promise)) {
}
private:
std::string host_;
bool prefer_ipv6_;
Promise<IPAddress> promise_;
ActorOwn<Wget> wget_;
double begin_time_ = 0;
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void start_up() final {
auto r_address = IPAddress::get_ip_address(host_);
if (r_address.is_ok()) {
promise_.set_value(r_address.move_as_ok());
return stop();
}
const int timeout = 10;
const int ttl = 3;
begin_time_ = Time::now();
auto wget_promise = PromiseCreator::lambda([actor_id = actor_id(this)](Result<unique_ptr<HttpQuery>> r_http_query) {
send_closure(actor_id, &GoogleDnsResolver::on_result, std::move(r_http_query));
});
wget_ = create_actor<Wget>(
"GoogleDnsResolver", std::move(wget_promise),
PSTRING() << "https://dns.google/resolve?name=" << url_encode(host_) << "&type=" << (prefer_ipv6_ ? 28 : 1),
std::vector<std::pair<string, string>>({{"Host", "dns.google"}}), timeout, ttl, prefer_ipv6_,
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SslCtx::VerifyPeer::Off);
}
static Result<IPAddress> get_ip_address(Result<unique_ptr<HttpQuery>> r_http_query) {
TRY_RESULT(http_query, std::move(r_http_query));
auto get_ip_address = [](JsonValue &answer) -> Result<IPAddress> {
auto &array = answer.get_array();
if (array.empty()) {
return Status::Error("Failed to parse DNS result: Answer is an empty array");
}
if (array[0].type() != JsonValue::Type::Object) {
return Status::Error("Failed to parse DNS result: Answer[0] is not an object");
}
auto &answer_0 = array[0].get_object();
TRY_RESULT(ip_str, answer_0.get_required_string_field("data"));
IPAddress ip;
TRY_STATUS(ip.init_host_port(ip_str, 0));
return ip;
};
if (!http_query->get_arg("Answer").empty()) {
TRY_RESULT(answer, json_decode(http_query->get_arg("Answer")));
if (answer.type() != JsonValue::Type::Array) {
return Status::Error("Expected JSON array");
}
return get_ip_address(answer);
} else {
TRY_RESULT(json_value, json_decode(http_query->content_));
if (json_value.type() != JsonValue::Type::Object) {
return Status::Error("Failed to parse DNS result: not an object");
}
auto &object = json_value.get_object();
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TRY_RESULT(answer, object.extract_required_field("Answer", JsonValue::Type::Array));
return get_ip_address(answer);
}
}
void on_result(Result<unique_ptr<HttpQuery>> r_http_query) {
auto end_time = Time::now();
auto result = get_ip_address(std::move(r_http_query));
VLOG(dns_resolver) << "Init IPv" << (prefer_ipv6_ ? "6" : "4") << " host = " << host_ << " in "
<< end_time - begin_time_ << " seconds to "
<< (result.is_ok() ? (PSLICE() << result.ok()) : CSlice("[invalid]"));
promise_.set_result(std::move(result));
stop();
}
};
class NativeDnsResolver final : public Actor {
public:
NativeDnsResolver(std::string host, bool prefer_ipv6, Promise<IPAddress> promise)
: host_(std::move(host)), prefer_ipv6_(prefer_ipv6), promise_(std::move(promise)) {
}
private:
std::string host_;
bool prefer_ipv6_;
Promise<IPAddress> promise_;
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void start_up() final {
IPAddress ip;
auto begin_time = Time::now();
auto status = ip.init_host_port(host_, 0, prefer_ipv6_);
auto end_time = Time::now();
VLOG(dns_resolver) << "Init host = " << host_ << " in " << end_time - begin_time << " seconds to " << ip;
if (status.is_error()) {
promise_.set_error(std::move(status));
} else {
promise_.set_value(std::move(ip));
}
stop();
}
};
} // namespace detail
int VERBOSITY_NAME(dns_resolver) = VERBOSITY_NAME(DEBUG);
GetHostByNameActor::GetHostByNameActor(Options options) : options_(std::move(options)) {
CHECK(!options_.resolver_types.empty());
}
void GetHostByNameActor::run(string host, int port, bool prefer_ipv6, Promise<IPAddress> promise) {
auto r_ascii_host = idn_to_ascii(host);
if (r_ascii_host.is_error()) {
return promise.set_error(r_ascii_host.move_as_error());
}
auto ascii_host = r_ascii_host.move_as_ok();
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if (ascii_host.empty()) {
return promise.set_error(Status::Error("Host is empty"));
}
auto begin_time = Time::now();
auto &value = cache_[prefer_ipv6].emplace(ascii_host, Value{{}, begin_time - 1.0}).first->second;
if (value.expires_at > begin_time) {
return promise.set_result(value.get_ip_port(port));
}
auto &query_ptr = active_queries_[prefer_ipv6][ascii_host];
if (query_ptr == nullptr) {
query_ptr = make_unique<Query>();
}
auto &query = *query_ptr;
query.promises.emplace_back(port, std::move(promise));
if (query.query.empty()) {
CHECK(query.promises.size() == 1);
query.real_host = std::move(host);
query.begin_time = Time::now();
run_query(std::move(ascii_host), prefer_ipv6, query);
}
}
void GetHostByNameActor::run_query(std::string host, bool prefer_ipv6, Query &query) {
auto promise = PromiseCreator::lambda([actor_id = actor_id(this), host, prefer_ipv6](Result<IPAddress> res) mutable {
send_closure(actor_id, &GetHostByNameActor::on_query_result, std::move(host), prefer_ipv6, std::move(res));
});
CHECK(query.query.empty());
CHECK(query.pos < options_.resolver_types.size());
auto resolver_type = options_.resolver_types[query.pos++];
query.query = [&] {
switch (resolver_type) {
case ResolverType::Native:
return ActorOwn<>(create_actor_on_scheduler<detail::NativeDnsResolver>(
"NativeDnsResolver", options_.scheduler_id, std::move(host), prefer_ipv6, std::move(promise)));
case ResolverType::Google:
return ActorOwn<>(create_actor_on_scheduler<detail::GoogleDnsResolver>(
"GoogleDnsResolver", options_.scheduler_id, std::move(host), prefer_ipv6, std::move(promise)));
default:
UNREACHABLE();
return ActorOwn<>();
}
}();
}
void GetHostByNameActor::on_query_result(std::string host, bool prefer_ipv6, Result<IPAddress> result) {
auto query_it = active_queries_[prefer_ipv6].find(host);
CHECK(query_it != active_queries_[prefer_ipv6].end());
auto &query = *query_it->second;
CHECK(!query.promises.empty());
CHECK(!query.query.empty());
if (result.is_error() && query.pos < options_.resolver_types.size()) {
query.query.reset();
return run_query(std::move(host), prefer_ipv6, query);
}
auto end_time = Time::now();
VLOG(dns_resolver) << "Init host = " << query.real_host << " in total of " << end_time - query.begin_time
<< " seconds to " << (result.is_ok() ? (PSLICE() << result.ok()) : CSlice("[invalid]"));
auto promises = std::move(query.promises);
auto value_it = cache_[prefer_ipv6].find(host);
CHECK(value_it != cache_[prefer_ipv6].end());
auto cache_timeout = result.is_ok() ? options_.ok_timeout : options_.error_timeout;
value_it->second = Value{std::move(result), end_time + cache_timeout};
active_queries_[prefer_ipv6].erase(query_it);
for (auto &promise : promises) {
promise.second.set_result(value_it->second.get_ip_port(promise.first));
}
}
} // namespace td