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//
//
// Copyright 2015 gRPC authors.
//
// 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.
//
//
#ifndef GRPC_SRC_CORE_LIB_IOMGR_RESOLVE_ADDRESS_H
#define GRPC_SRC_CORE_LIB_IOMGR_RESOLVE_ADDRESS_H
#include <grpc/support/port_platform.h>
#include <stddef.h>
#include "y_absl/status/statusor.h"
#include <grpc/event_engine/event_engine.h>
#include "src/core/lib/gprpp/orphanable.h"
#include "src/core/lib/gprpp/time.h"
#include "src/core/lib/iomgr/pollset_set.h"
#include "src/core/lib/iomgr/port.h"
#include "src/core/lib/iomgr/resolved_address.h"
#define GRPC_MAX_SOCKADDR_SIZE 128
namespace grpc_core {
extern const char* kDefaultSecurePort;
constexpr int kDefaultSecurePortInt = 443;
constexpr Duration kDefaultDNSRequestTimeout = Duration::Minutes(2);
// A singleton class used for async and blocking DNS resolution
class DNSResolver {
public:
using TaskHandle = ::grpc_event_engine::experimental::EventEngine::
DNSResolver::LookupTaskHandle;
static constexpr TaskHandle kNullHandle{0, 0};
virtual ~DNSResolver() {}
static TString HandleToString(TaskHandle handle);
// Asynchronously resolve name. Use \a default_port if a port isn't designated
// in \a name, otherwise use the port in \a name. On completion, \a on_done is
// invoked with the result.
//
// Note for implementations: calls may acquire locks in \a on_done which
// were previously held while starting the request. Therefore,
// implementations must not invoke \a on_done inline from the call site that
// starts the request. The DNSCallbackExecCtxScheduler utility may help
// address this.
//
// \a interested_parties may be deleted after a request is cancelled.
virtual TaskHandle LookupHostname(
std::function<void(y_absl::StatusOr<std::vector<grpc_resolved_address>>)>
on_resolved,
y_absl::string_view name, y_absl::string_view default_port, Duration timeout,
grpc_pollset_set* interested_parties, y_absl::string_view name_server) = 0;
// Resolve name in a blocking fashion. Use \a default_port if a port isn't
// designated in \a name, otherwise use the port in \a name.
virtual y_absl::StatusOr<std::vector<grpc_resolved_address>>
LookupHostnameBlocking(y_absl::string_view name,
y_absl::string_view default_port) = 0;
// Asynchronously resolve an SRV Record to Hostnames.
// On completion, \a on_done is invoked with the result.
//
// The same caveats in \a LookupHostname apply here as well.
//
// TODO(hork): return std::vector<SRVRecord> and ask the client to do the
// subsequent hostname lookups.
virtual TaskHandle LookupSRV(
std::function<void(y_absl::StatusOr<std::vector<grpc_resolved_address>>)>
on_resolved,
y_absl::string_view name, Duration timeout,
grpc_pollset_set* interested_parties, y_absl::string_view name_server) = 0;
// Asynchronously resolve a TXT Record. On completion, \a on_done is invoked
// with the resulting string.
//
// The same caveats in \a LookupHostname apply here.
virtual TaskHandle LookupTXT(
std::function<void(y_absl::StatusOr<TString>)> on_resolved,
y_absl::string_view name, Duration timeout,
grpc_pollset_set* interested_parties, y_absl::string_view name_server) = 0;
// This shares the same semantics with \a EventEngine::Cancel: successfully
// cancelled lookups will not have their callbacks executed, and this
// method returns true. If a TaskHandle is unknown, this method should return
// false.
virtual bool Cancel(TaskHandle handle) = 0;
};
// Override the active DNS resolver which should be used for all DNS
// resolution in gRPC.
void ResetDNSResolver(std::shared_ptr<DNSResolver> resolver);
// Get the singleton DNS resolver instance which should be used for all
// DNS resolution in gRPC.
std::shared_ptr<DNSResolver> GetDNSResolver();
} // namespace grpc_core
#endif // GRPC_SRC_CORE_LIB_IOMGR_RESOLVE_ADDRESS_H
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