host_resolver_manager.h | Explore in Territory

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_DNS_HOST_RESOLVER_MANAGER_H_
#define NET_DNS_HOST_RESOLVER_MANAGER_H_

#include <stddef.h>
#include <stdint.h>

#include <deque>
#include <map>
#include <memory>
#include <optional>
#include <set>
#include <string>
#include <string_view>
#include <vector>

#include "base/functional/callback.h"
#include "base/functional/callback_helpers.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/scoped_refptr.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "base/values.h"
#include "net/base/completion_once_callback.h"
#include "net/base/host_port_pair.h"
#include "net/base/network_anonymization_key.h"
#include "net/base/network_change_notifier.h"
#include "net/base/network_handle.h"
#include "net/base/prioritized_dispatcher.h"
#include "net/dns/dns_config.h"
#include "net/dns/host_cache.h"
#include "net/dns/host_resolver.h"
#include "net/dns/httpssvc_metrics.h"
#include "net/dns/public/dns_config_overrides.h"
#include "net/dns/public/dns_query_type.h"
#include "net/dns/public/secure_dns_mode.h"
#include "net/dns/public/secure_dns_policy.h"
#include "net/dns/resolve_context.h"
#include "net/dns/system_dns_config_change_notifier.h"
#include "net/log/net_log_with_source.h"
#include "net/socket/datagram_client_socket.h"
#include "third_party/abseil-cpp/absl/types/variant.h"
#include "url/gurl.h"
#include "url/scheme_host_port.h"

namespace base {
class TickClock;
}  // namespace base

namespace net {

class DnsClient;
class DnsProbeRunner;
class IPAddress;
class MDnsClient;
class ClientSocketFactory;
class MDnsSocketFactory;
class NetLog;

// Scheduler and controller of host resolution requests. Because of the global
// nature of host resolutions, this class is generally expected to be singleton
// within the browser and only be interacted with through per-context
// ContextHostResolver objects (which are themselves generally interacted with
// though the HostResolver interface).
//
// For each hostname that is requested, HostResolver creates a
// HostResolverManager::Job. When this job gets dispatched it creates a task
// (HostResolverSystemTask for the system resolver or DnsTask for the async
// resolver) which resolves the hostname. If requests for that same host are
// made during the job's lifetime, they are attached to the existing job rather
// than creating a new one. This avoids doing parallel resolves for the same
// host.
//
// The way these classes fit together is illustrated by:
//
//
//            +----------- HostResolverManager ----------+
//            |                    |                     |
//           Job                  Job                   Job
//    (for host1, fam1)    (for host2, fam2)     (for hostx, famx)
//       /    |   |            /   |   |             /   |   |
//   Request ... Request  Request ... Request   Request ... Request
//  (port1)     (port2)  (port3)      (port4)  (port5)      (portX)
//
// When a HostResolverManager::Job finishes, the callbacks of each waiting
// request are run on the origin thread.
//
// Thread safety: This class is not threadsafe, and must only be called
// from one thread!
//
// The HostResolverManager enforces limits on the maximum number of concurrent
// threads using PrioritizedDispatcher::Limits.
//
// Jobs are ordered in the queue based on their priority and order of arrival.
class NET_EXPORT HostResolverManager
    : public NetworkChangeNotifier::IPAddressObserver,
      public NetworkChangeNotifier::ConnectionTypeObserver,
      public SystemDnsConfigChangeNotifier::Observer { … };

// Resolves a local hostname (such as "localhost" or "vhost.localhost") into
// IP endpoints (with port 0). Returns true if |host| is a local
// hostname and false otherwise. Names will resolve to both IPv4 and IPv6.
// This function is only exposed so it can be unit-tested.
// TODO(tfarina): It would be better to change the tests so this function
// gets exercised indirectly through HostResolverManager.
NET_EXPORT_PRIVATE bool ResolveLocalHostname(
    std::string_view host,
    std::vector<IPEndPoint>* address_list);

}  // namespace net

#endif  // NET_DNS_HOST_RESOLVER_MANAGER_H_
chromium/net/dns/host_resolver_manager.h
