blob: 8c741c292ff3f370266731f66f4bfa24bfd5bd1c [file] [log] [blame]
// 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.
#include <stdint.h>
#include <memory>
#include <optional>
#include <string>
#include <string_view>
#include "base/functional/callback.h"
#include "base/memory/weak_ptr.h"
#include "base/time/time.h"
#include "net/base/request_priority.h"
#include "net/dns/opt_record_rdata.h"
#include "net/dns/public/secure_dns_mode.h"
#include "net/dns/record_rdata.h"
#include "url/gurl.h"
namespace net {
class DnsResponse;
class DnsSession;
class NetLogWithSource;
class ResolveContext;
// The hostname probed by CreateDohProbeRunner().
inline constexpr std::string_view kDohProbeHostname = "";
// DnsTransaction implements a stub DNS resolver as defined in RFC 1034.
// The DnsTransaction takes care of retransmissions, name server fallback (or
// round-robin), suffix search, and simple response validation ("does it match
// the query") to fight poisoning.
// Destroying DnsTransaction cancels the underlying network effort.
class NET_EXPORT_PRIVATE DnsTransaction {
// Called with the response or nullptr if no matching response was received.
// Note that the `GetDottedName()` of the response may be different than the
// original `hostname` (passed to `DnsTransactionFactory::CreateTransaction()`
// as a result of suffix search.
using ResponseCallback =
base::OnceCallback<void(int neterror, const DnsResponse* response)>;
virtual ~DnsTransaction() = default;
// Returns the original |hostname|.
virtual const std::string& GetHostname() const = 0;
// Returns the |qtype|.
virtual uint16_t GetType() const = 0;
// Starts the transaction. Always completes asynchronously.
virtual void Start(ResponseCallback callback) = 0;
virtual void SetRequestPriority(RequestPriority priority) = 0;
// Startable/Cancellable object to represent a DNS probe sequence.
class DnsProbeRunner {
// Destruction cancels the probes.
virtual ~DnsProbeRunner() = default;
// Starts all applicable probes that are not already running. May be called
// multiple times, but should not be called after destruction of the
// DnsTransactionFactory.
// Set |network_change| to indicate if this start or restart was triggered by
// a network connection change. Only used for logging and metrics.
virtual void Start(bool network_change) = 0;
// Gets the delay until the next scheduled probe to the specified DoH server.
// Returns base::TimeDelta() if no probe scheduled.
virtual base::TimeDelta GetDelayUntilNextProbeForTest(
size_t doh_server_index) const = 0;
// Creates DnsTransaction which performs asynchronous DNS search.
// It does NOT perform caching, aggregation or prioritization of transactions.
// Destroying the factory does NOT affect any already created DnsTransactions.
// DnsProbeRunners, however, will safely abort themselves on destruction of
// their creating factory, and they should only be started or restarted while
// the factory is still alive.
class NET_EXPORT_PRIVATE DnsTransactionFactory {
virtual ~DnsTransactionFactory();
// Creates DnsTransaction for the given |hostname| and |qtype| (assuming
// QCLASS is IN). |hostname| should be in the dotted form. A dot at the end
// implies the domain name is fully-qualified and will be exempt from suffix
// search. |hostname| should not be an IP literal.
// The |net_log| is used as the parent log.
// |secure| specifies whether DNS lookups should be performed using DNS-over-
// HTTPS (DoH) or using plaintext DNS.
// When |fast_timeout| is true, the transaction will timeout quickly after
// making its DNS attempts, without necessarily waiting long enough to allow
// slower-than-average requests to complete. Intended as an optimization for
// cases where the caller has reasonable fallback options to the transaction
// and it would be beneficial to move on to those options sooner on signals
// that the transaction is potentially slow or problematic.
[[nodiscard]] virtual std::unique_ptr<DnsTransaction> CreateTransaction(
std::string hostname,
uint16_t qtype,
const NetLogWithSource& net_log,
bool secure,
SecureDnsMode secure_dns_mode,
ResolveContext* resolve_context,
bool fast_timeout) = 0;
// Creates a runner to run the DoH probe sequence for all configured DoH
// resolvers.
[[nodiscard]] virtual std::unique_ptr<DnsProbeRunner> CreateDohProbeRunner(
ResolveContext* resolve_context) = 0;
// The given EDNS0 option will be included in all DNS queries performed by
// transactions from this factory.
virtual void AddEDNSOption(std::unique_ptr<OptRecordRdata::Opt> opt) = 0;
// Returns the default SecureDnsMode in the config.
virtual SecureDnsMode GetSecureDnsModeForTest() = 0;
// Creates a DnsTransactionFactory which creates DnsTransactionImpl using the
// |session|.
[[nodiscard]] static std::unique_ptr<DnsTransactionFactory> CreateFactory(
DnsSession* session);
base::WeakPtrFactory<DnsTransactionFactory> weak_factory_{this};
} // namespace net