123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574 |
- // Copyright (c) 2012 The Chromium Authors. All rights reserved.
- // 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 <set>
- #include <string>
- #include <vector>
- #include "base/callback.h"
- #include "base/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/strings/string_piece.h"
- #include "base/time/time.h"
- #include "base/timer/timer.h"
- #include "net/base/completion_once_callback.h"
- #include "net/base/host_port_pair.h"
- #include "net/base/network_change_notifier.h"
- #include "net/base/network_handle.h"
- #include "net/base/network_isolation_key.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/host_resolver_proc.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 "third_party/abseil-cpp/absl/types/optional.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 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
- // (ProcTask 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 {
- public:
- using MdnsListener = HostResolver::MdnsListener;
- using ResolveHostParameters = HostResolver::ResolveHostParameters;
- using PassKey = base::PassKey<HostResolverManager>;
- // Creates a HostResolver as specified by |options|. Blocking tasks are run in
- // ThreadPool.
- //
- // If Options.enable_caching is true, a cache is created using
- // HostCache::CreateDefaultCache(). Otherwise no cache is used.
- //
- // Options.GetDispatcherLimits() determines the maximum number of jobs that
- // the resolver will run at once. This upper-bounds the total number of
- // outstanding DNS transactions (not counting retransmissions and retries).
- //
- // |net_log| and |system_dns_config_notifier|, if non-null, must remain valid
- // for the life of the HostResolverManager.
- HostResolverManager(const HostResolver::ManagerOptions& options,
- SystemDnsConfigChangeNotifier* system_dns_config_notifier,
- NetLog* net_log);
- HostResolverManager(const HostResolverManager&) = delete;
- HostResolverManager& operator=(const HostResolverManager&) = delete;
- // If any completion callbacks are pending when the resolver is destroyed,
- // the host resolutions are cancelled, and the completion callbacks will not
- // be called.
- ~HostResolverManager() override;
- // Same as constructor above, but binds the HostResolverManager to
- // `target_network`: all DNS requests will be performed for `target_network`
- // only, requests will fail if `target_network` disconnects. Only
- // HostResolvers bound to the same network will be able to use this.
- // Only implemented for Android.
- static std::unique_ptr<HostResolverManager>
- CreateNetworkBoundHostResolverManager(
- const HostResolver::ManagerOptions& options,
- handles::NetworkHandle target_network,
- NetLog* net_log);
- // |resolve_context| must have already been added (via
- // RegisterResolveContext()). If |optional_parameters| specifies any cache
- // usage other than LOCAL_ONLY, there must be a 1:1 correspondence between
- // |resolve_context| and |host_cache|, and both should come from the same
- // ContextHostResolver.
- //
- // TODO(crbug.com/1022059): Use the HostCache out of the ResolveContext
- // instead of passing it separately.
- std::unique_ptr<HostResolver::ResolveHostRequest> CreateRequest(
- HostResolver::Host host,
- NetworkIsolationKey network_isolation_key,
- NetLogWithSource net_log,
- absl::optional<ResolveHostParameters> optional_parameters,
- ResolveContext* resolve_context,
- HostCache* host_cache);
- // |resolve_context| is the context to use for the probes, and it is expected
- // to be the context of the calling ContextHostResolver.
- std::unique_ptr<HostResolver::ProbeRequest> CreateDohProbeRequest(
- ResolveContext* resolve_context);
- std::unique_ptr<MdnsListener> CreateMdnsListener(const HostPortPair& host,
- DnsQueryType query_type);
- // Enables or disables the built-in asynchronous DnsClient. If enabled, by
- // default (when no |ResolveHostParameters::source| is specified), the
- // DnsClient will be used for resolves and, in case of failure, resolution
- // will fallback to the system resolver (HostResolverProc from
- // ProcTaskParams). If the DnsClient is not pre-configured with a valid
- // DnsConfig, a new config is fetched from NetworkChangeNotifier.
- //
- // Setting to |true| has no effect if |ENABLE_BUILT_IN_DNS| not defined.
- virtual void SetInsecureDnsClientEnabled(bool enabled,
- bool additional_dns_types_enabled);
- base::Value GetDnsConfigAsValue() const;
- // Sets overriding configuration that will replace or add to configuration
- // read from the system for DnsClient resolution.
- void SetDnsConfigOverrides(DnsConfigOverrides overrides);
- // Support for invalidating cached per-context data on changes to network or
- // DNS configuration. ContextHostResolvers should register/deregister
- // themselves here rather than attempting to listen for relevant network
- // change signals themselves because HostResolverManager needs to coordinate
- // invalidations with in-progress resolves and because some invalidations are
- // triggered by changes to manager properties/configuration rather than pure
- // network changes.
- //
- // Note: Invalidation handling must not call back into HostResolverManager as
- // the invalidation is expected to be handled atomically with other clearing
- // and aborting actions.
- void RegisterResolveContext(ResolveContext* context);
- void DeregisterResolveContext(const ResolveContext* context);
- void set_proc_params_for_test(const ProcTaskParams& proc_params) {
- proc_params_ = proc_params;
- }
- void InvalidateCachesForTesting() { InvalidateCaches(); }
- void SetTickClockForTesting(const base::TickClock* tick_clock);
- // Configures maximum number of Jobs in the queue. Exposed for testing.
- // Only allowed when the queue is empty.
- void SetMaxQueuedJobsForTesting(size_t value);
- void SetMdnsSocketFactoryForTesting(
- std::unique_ptr<MDnsSocketFactory> socket_factory);
- void SetMdnsClientForTesting(std::unique_ptr<MDnsClient> client);
- // To simulate modifications it would have received if |dns_client| had been
- // in place before calling this, DnsConfig will be set with the configuration
- // from the previous DnsClient being replaced (including system config if
- // |dns_client| does not already contain a system config). This means tests do
- // not normally need to worry about ordering between setting a test client and
- // setting DnsConfig.
- void SetDnsClientForTesting(std::unique_ptr<DnsClient> dns_client);
- // Explicitly disable the system resolver even if tests have set a catch-all
- // DNS block. See `ForceSystemResolverDueToTestOverride`.
- void DisableSystemResolverForTesting() {
- system_resolver_disabled_for_testing_ = true;
- }
- // Sets the last IPv6 probe result for testing. Uses the standard timeout
- // duration, so it's up to the test fixture to ensure it doesn't expire by
- // mocking time, if expiration would pose a problem.
- void SetLastIPv6ProbeResultForTesting(bool last_ipv6_probe_result);
- // Allows the tests to catch slots leaking out of the dispatcher. One
- // HostResolverManager::Job could occupy multiple PrioritizedDispatcher job
- // slots.
- size_t num_running_dispatcher_jobs_for_tests() const {
- return dispatcher_->num_running_jobs();
- }
- size_t num_jobs_for_testing() const { return jobs_.size(); }
- bool check_ipv6_on_wifi_for_testing() const { return check_ipv6_on_wifi_; }
- handles::NetworkHandle target_network_for_testing() const {
- return target_network_;
- }
- const HostResolver::HttpsSvcbOptions& https_svcb_options_for_testing() const {
- return https_svcb_options_;
- }
- // Public to be called from std::make_unique. Not to be called directly.
- HostResolverManager(base::PassKey<HostResolverManager>,
- const HostResolver::ManagerOptions& options,
- SystemDnsConfigChangeNotifier* system_dns_config_notifier,
- handles::NetworkHandle target_network,
- NetLog* net_log);
- protected:
- // Callback from HaveOnlyLoopbackAddresses probe.
- void SetHaveOnlyLoopbackAddresses(bool result);
- // Sets the task runner used for HostResolverProc tasks.
- void SetTaskRunnerForTesting(scoped_refptr<base::TaskRunner> task_runner);
- private:
- friend class HostResolverManagerTest;
- friend class HostResolverManagerDnsTest;
- class Job;
- struct JobKey;
- class ProcTask;
- class LoopbackProbeJob;
- class DnsTask;
- class RequestImpl;
- class ProbeRequestImpl;
- using JobMap = std::map<JobKey, std::unique_ptr<Job>>;
- // Task types that a Job might run.
- enum class TaskType {
- PROC,
- DNS,
- SECURE_DNS,
- MDNS,
- CACHE_LOOKUP,
- INSECURE_CACHE_LOOKUP,
- SECURE_CACHE_LOOKUP,
- CONFIG_PRESET,
- };
- // Returns true if the task is local, synchronous, and instantaneous.
- static bool IsLocalTask(TaskType task);
- // Attempts host resolution for |request|. Generally only expected to be
- // called from RequestImpl::Start().
- int Resolve(RequestImpl* request);
- // Attempts host resolution using fast local sources: IP literal resolution,
- // cache lookup, HOSTS lookup (if enabled), and localhost. Returns results
- // with error() OK if successful, ERR_NAME_NOT_RESOLVED if input is invalid,
- // or ERR_DNS_CACHE_MISS if the host could not be resolved using local
- // sources.
- //
- // On ERR_DNS_CACHE_MISS and OK, |out_tasks| contains the tentative
- // sequence of tasks that a future job should run.
- //
- // If results are returned from the host cache, |out_stale_info| will be
- // filled in with information on how stale or fresh the result is. Otherwise,
- // |out_stale_info| will be set to |absl::nullopt|.
- //
- // If |cache_usage == ResolveHostParameters::CacheUsage::STALE_ALLOWED|, then
- // stale cache entries can be returned.
- HostCache::Entry ResolveLocally(
- const JobKey& job_key,
- const IPAddress& ip_address,
- ResolveHostParameters::CacheUsage cache_usage,
- SecureDnsPolicy secure_dns_policy,
- const NetLogWithSource& request_net_log,
- HostCache* cache,
- std::deque<TaskType>* out_tasks,
- absl::optional<HostCache::EntryStaleness>* out_stale_info);
- // Creates and starts a Job to asynchronously attempt to resolve
- // |request|.
- void CreateAndStartJob(JobKey key,
- std::deque<TaskType> tasks,
- RequestImpl* request);
- HostResolverManager::Job* AddJobWithoutRequest(
- JobKey key,
- ResolveHostParameters::CacheUsage cache_usage,
- HostCache* host_cache,
- std::deque<TaskType> tasks,
- RequestPriority priority,
- const NetLogWithSource& source_net_log);
- // Resolves the IP literal hostname represented by `ip_address`.
- HostCache::Entry ResolveAsIP(DnsQueryTypeSet query_types,
- bool resolve_canonname,
- const IPAddress& ip_address);
- // Returns the result iff |cache_usage| permits cache lookups and a positive
- // match is found for |key| in |cache|. |out_stale_info| must be non-null, and
- // will be filled in with details of the entry's staleness if an entry is
- // returned, otherwise it will be set to |absl::nullopt|.
- absl::optional<HostCache::Entry> MaybeServeFromCache(
- HostCache* cache,
- const HostCache::Key& key,
- ResolveHostParameters::CacheUsage cache_usage,
- bool ignore_secure,
- const NetLogWithSource& source_net_log,
- absl::optional<HostCache::EntryStaleness>* out_stale_info);
- // Returns any preset resolution result from the active DoH configuration that
- // matches |key.host|.
- absl::optional<HostCache::Entry> MaybeReadFromConfig(const JobKey& key);
- // Populates the secure cache with an optimal entry that supersedes the
- // bootstrap result.
- void StartBootstrapFollowup(JobKey key,
- HostCache* host_cache,
- const NetLogWithSource& source_net_log);
- // Iff we have a DnsClient with a valid DnsConfig and we're not about to
- // attempt a system lookup, then try to resolve the query using the HOSTS
- // file.
- absl::optional<HostCache::Entry> ServeFromHosts(
- base::StringPiece hostname,
- DnsQueryTypeSet query_types,
- bool default_family_due_to_no_ipv6,
- const std::deque<TaskType>& tasks);
- // Iff |key| is for a localhost name (RFC 6761) and address DNS query type,
- // returns a results entry with the loopback IP.
- absl::optional<HostCache::Entry> ServeLocalhost(
- base::StringPiece hostname,
- DnsQueryTypeSet query_types,
- bool default_family_due_to_no_ipv6);
- // Returns the secure dns mode to use for a job, taking into account the
- // global DnsConfig mode and any per-request policy.
- SecureDnsMode GetEffectiveSecureDnsMode(SecureDnsPolicy secure_dns_policy);
- // Returns true when a catch-all DNS block has been set for tests, unless
- // `SetDisableSystemResolverForTesting` has been called to explicitly disable
- // that safety net. DnsTasks should never be issued when this returns true.
- bool ShouldForceSystemResolverDueToTestOverride() const;
- // Helper method to add DnsTasks and related tasks based on the SecureDnsMode
- // and fallback parameters. If |prioritize_local_lookups| is true, then we
- // may push an insecure cache lookup ahead of a secure DnsTask.
- void PushDnsTasks(bool proc_task_allowed,
- SecureDnsMode secure_dns_mode,
- bool insecure_tasks_allowed,
- bool allow_cache,
- bool prioritize_local_lookups,
- ResolveContext* resolve_context,
- std::deque<TaskType>* out_tasks);
- // Initialized the sequence of tasks to run to resolve a request. The sequence
- // may be adjusted later and not all tasks need to be run.
- void CreateTaskSequence(const JobKey& job_key,
- ResolveHostParameters::CacheUsage cache_usage,
- SecureDnsPolicy secure_dns_policy,
- std::deque<TaskType>* out_tasks);
- // Determines "effective" request parameters using manager properties and IPv6
- // reachability.
- void GetEffectiveParametersForRequest(
- const absl::variant<url::SchemeHostPort, std::string>& host,
- DnsQueryType dns_query_type,
- HostResolverFlags flags,
- SecureDnsPolicy secure_dns_policy,
- bool is_ip,
- const NetLogWithSource& net_log,
- DnsQueryTypeSet* out_effective_types,
- HostResolverFlags* out_effective_flags,
- SecureDnsMode* out_effective_secure_dns_mode);
- // Probes IPv6 support and returns true if IPv6 support is enabled.
- // Results are cached, i.e. when called repeatedly this method returns result
- // from the first probe for some time before probing again.
- bool IsIPv6Reachable(const NetLogWithSource& net_log);
- // Sets |last_ipv6_probe_result_| and updates |last_ipv6_probe_time_|.
- void SetLastIPv6ProbeResult(bool last_ipv6_probe_result);
- // Attempts to connect a UDP socket to |dest|:53. Virtual for testing.
- virtual bool IsGloballyReachable(const IPAddress& dest,
- const NetLogWithSource& net_log);
- // Asynchronously checks if only loopback IPs are available.
- virtual void RunLoopbackProbeJob();
- // Records the result in cache if cache is present.
- void CacheResult(HostCache* cache,
- const HostCache::Key& key,
- const HostCache::Entry& entry,
- base::TimeDelta ttl);
- // Removes |job_it| from |jobs_| and return.
- std::unique_ptr<Job> RemoveJob(JobMap::iterator job_it);
- // Removes Jobs for this context.
- void RemoveAllJobs(const ResolveContext* context);
- // Aborts all jobs (both scheduled and running) which are not targeting a
- // specific network with ERR_NETWORK_CHANGED and notifies their requests.
- // Aborts only running jobs if `in_progress_only` is true. Might start new
- // jobs.
- void AbortJobsWithoutTargetNetwork(bool in_progress_only);
- // Aborts all in progress insecure DnsTasks. In-progress jobs will fall back
- // to ProcTasks if able and otherwise abort with |error|. Might start new
- // jobs, if any jobs were taking up two dispatcher slots.
- //
- // If |fallback_only|, insecure DnsTasks will only abort if they can fallback
- // to ProcTask.
- void AbortInsecureDnsTasks(int error, bool fallback_only);
- // Attempts to serve each Job in |jobs_| from the HOSTS file if we have
- // a DnsClient with a valid DnsConfig.
- void TryServingAllJobsFromHosts();
- // NetworkChangeNotifier::IPAddressObserver:
- void OnIPAddressChanged() override;
- // NetworkChangeNotifier::ConnectionTypeObserver:
- void OnConnectionTypeChanged(
- NetworkChangeNotifier::ConnectionType type) override;
- // SystemDnsConfigChangeNotifier::Observer:
- void OnSystemDnsConfigChanged(absl::optional<DnsConfig> config) override;
- void UpdateJobsForChangedConfig();
- // Called on successful resolve after falling back to ProcTask after a failed
- // DnsTask resolve.
- void OnFallbackResolve(int dns_task_error);
- int GetOrCreateMdnsClient(MDnsClient** out_client);
- // |network_change| indicates whether or not the invalidation was triggered
- // by a network connection change.
- void InvalidateCaches(bool network_change = false);
- void UpdateConnectionType(NetworkChangeNotifier::ConnectionType type);
- bool IsBoundToNetwork() const {
- return target_network_ != handles::kInvalidNetworkHandle;
- }
- // Returns |nullptr| if DoH probes are currently not allowed (due to
- // configuration or current connection state).
- std::unique_ptr<DnsProbeRunner> CreateDohProbeRunner(
- ResolveContext* resolve_context);
- // Used for multicast DNS tasks. Created on first use using
- // GetOrCreateMndsClient().
- std::unique_ptr<MDnsSocketFactory> mdns_socket_factory_;
- std::unique_ptr<MDnsClient> mdns_client_;
- // Map from HostCache::Key to a Job.
- JobMap jobs_;
- // Starts Jobs according to their priority and the configured limits.
- std::unique_ptr<PrioritizedDispatcher> dispatcher_;
- // Limit on the maximum number of jobs queued in |dispatcher_|.
- size_t max_queued_jobs_ = 0;
- // Parameters for ProcTask.
- ProcTaskParams proc_params_;
- raw_ptr<NetLog> net_log_;
- // If present, used by DnsTask and ServeFromHosts to resolve requests.
- std::unique_ptr<DnsClient> dns_client_;
- raw_ptr<SystemDnsConfigChangeNotifier> system_dns_config_notifier_;
- handles::NetworkHandle target_network_;
- // False if IPv6 should not be attempted and assumed unreachable when on a
- // WiFi connection. See https://crbug.com/696569 for further context.
- bool check_ipv6_on_wifi_;
- base::TimeTicks last_ipv6_probe_time_;
- bool last_ipv6_probe_result_ = true;
- // Any resolver flags that should be added to a request by default.
- HostResolverFlags additional_resolver_flags_ = 0;
- // Allow fallback to ProcTask if DnsTask fails.
- bool allow_fallback_to_proctask_ = true;
- // Task runner used for DNS lookups using the system resolver. Normally a
- // ThreadPool task runner, but can be overridden for tests.
- scoped_refptr<base::TaskRunner> proc_task_runner_;
- // Shared tick clock, overridden for testing.
- raw_ptr<const base::TickClock> tick_clock_;
- // When true, ignore the catch-all DNS block if it exists.
- bool system_resolver_disabled_for_testing_ = false;
- // For per-context cache invalidation notifications.
- base::ObserverList<ResolveContext,
- true /* check_empty */,
- false /* allow_reentrancy */>
- registered_contexts_;
- bool invalidation_in_progress_ = false;
- // Helper for metrics associated with `features::kDnsHttpssvc`.
- HttpssvcExperimentDomainCache httpssvc_domain_cache_;
- // An experimental flag for features::kUseDnsHttpsSvcb.
- HostResolver::HttpsSvcbOptions https_svcb_options_;
- THREAD_CHECKER(thread_checker_);
- base::WeakPtrFactory<HostResolverManager> weak_ptr_factory_{this};
- base::WeakPtrFactory<HostResolverManager> probe_weak_ptr_factory_{this};
- };
- // 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(
- base::StringPiece host,
- std::vector<IPEndPoint>* address_list);
- } // namespace net
- #endif // NET_DNS_HOST_RESOLVER_MANAGER_H_
|