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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROME_BROWSER_NET_DNS_PROBE_RUNNER_H_
#define CHROME_BROWSER_NET_DNS_PROBE_RUNNER_H_
#include "base/functional/bind.h"
#include "base/functional/callback.h"
#include "base/sequence_checker.h"
#include "mojo/public/cpp/bindings/receiver.h"
#include "mojo/public/cpp/bindings/remote.h"
#include "net/dns/public/host_resolver_results.h"
#include "services/network/public/cpp/network_context_getter.h"
#include "services/network/public/cpp/resolve_host_client_base.h"
#include "services/network/public/mojom/host_resolver.mojom-forward.h"
namespace network {
namespace mojom {
class NetworkContext;
}
} // namespace network
namespace chrome_browser_net {
// Runs DNS probes using a HostResolver and evaluates the responses.
// (Currently requests A records for google.com and expects at least one IP
// address in the response.)
// Used by DnsProbeService to probe the system and public DNS configurations.
class DnsProbeRunner : public network::ResolveHostClientBase {
public:
static const char kKnownGoodHostname[];
// Used in histograms; add new entries at the bottom, and don't remove any.
enum Result {
UNKNOWN,
CORRECT, // Response contains at least one A record.
INCORRECT, // Response claimed success but included no A records.
FAILING, // Response included an error or was malformed.
UNREACHABLE // No response received (timeout, network unreachable, etc.).
};
// Creates a probe runner that will use |dns_config_overrides| for the dns
// configuration and will use |network_context_getter| to get the
// NetworkContext to create the HostResolver. The |network_context_getter|
// may be called multiple times.
DnsProbeRunner(net::DnsConfigOverrides dns_config_overrides,
const network::NetworkContextGetter& network_context_getter);
DnsProbeRunner(const DnsProbeRunner&) = delete;
DnsProbeRunner& operator=(const DnsProbeRunner&) = delete;
~DnsProbeRunner() override;
// Starts a probe. |callback| will be called asynchronously when the result
// is ready, and will not be called if the DnsProbeRunner is destroyed before
// the probe finishes. Must not be called again until the callback is called,
// but may be called during the callback.
void RunProbe(base::OnceClosure callback);
// Returns true if a probe is running. Guaranteed to return true after
// RunProbe returns, and false during and after the callback.
bool IsRunning() const;
// Returns the result of the last probe.
Result result() const {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
return result_;
}
// network::ResolveHostClientBase impl:
void OnComplete(int32_t result,
const net::ResolveErrorInfo& resolve_error_info,
const std::optional<net::AddressList>& resolved_addresses,
const std::optional<net::HostResolverEndpointResults>&
endpoint_results_with_metadata) override;
net::DnsConfigOverrides GetConfigOverridesForTesting() {
return dns_config_overrides_;
}
private:
void CreateHostResolver();
void OnMojoConnectionError();
mojo::Receiver<network::mojom::ResolveHostClient> receiver_{this};
net::DnsConfigOverrides dns_config_overrides_;
network::NetworkContextGetter network_context_getter_;
mojo::Remote<network::mojom::HostResolver> host_resolver_;
// The callback passed to |RunProbe|. Cleared right before calling the
// callback.
base::OnceClosure callback_;
Result result_{UNKNOWN};
SEQUENCE_CHECKER(sequence_checker_);
};
} // namespace chrome_browser_net
#endif // CHROME_BROWSER_NET_DNS_PROBE_RUNNER_H_
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