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// Copyright 2013 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.
#include "chrome/browser/net/dns_probe_runner.h"
#include "base/bind.h"
#include "content/public/browser/browser_thread.h"
#include "net/base/address_list.h"
#include "net/base/ip_endpoint.h"
#include "net/base/net_errors.h"
#include "net/base/net_util.h"
#include "net/base/network_change_notifier.h"
#include "net/dns/dns_client.h"
#include "net/dns/dns_protocol.h"
#include "net/dns/dns_response.h"
#include "net/dns/dns_transaction.h"
#include "net/log/net_log.h"
using base::TimeDelta;
using content::BrowserThread;
using net::AddressList;
using net::BoundNetLog;
using net::DnsClient;
using net::DnsResponse;
using net::DnsTransaction;
using net::DnsTransactionFactory;
using net::IPAddressNumber;
using net::IPEndPoint;
using net::NetLog;
using net::NetworkChangeNotifier;
using net::ParseIPLiteralToNumber;
namespace chrome_browser_net {
const char* DnsProbeRunner::kKnownGoodHostname = "google.com";
namespace {
DnsProbeRunner::Result EvaluateResponse(
int net_error,
const DnsResponse* response) {
switch (net_error) {
case net::OK:
break;
// ERR_NAME_NOT_RESOLVED maps to NXDOMAIN, which means the server is working
// but returned a wrong answer.
case net::ERR_NAME_NOT_RESOLVED:
return DnsProbeRunner::INCORRECT;
// These results mean we heard *something* from the DNS server, but it was
// unsuccessful (SERVFAIL) or malformed.
case net::ERR_DNS_MALFORMED_RESPONSE:
case net::ERR_DNS_SERVER_REQUIRES_TCP: // Shouldn't happen; DnsTransaction
// will retry with TCP.
case net::ERR_DNS_SERVER_FAILED:
case net::ERR_DNS_SORT_ERROR: // Can only happen if the server responds.
return DnsProbeRunner::FAILING;
// Any other error means we never reached the DNS server in the first place.
case net::ERR_DNS_TIMED_OUT:
default:
// Something else happened, probably at a network level.
return DnsProbeRunner::UNREACHABLE;
}
AddressList addr_list;
TimeDelta ttl;
DnsResponse::Result result = response->ParseToAddressList(&addr_list, &ttl);
if (result != DnsResponse::DNS_PARSE_OK)
return DnsProbeRunner::FAILING;
else if (addr_list.empty())
return DnsProbeRunner::INCORRECT;
else
return DnsProbeRunner::CORRECT;
}
} // namespace
DnsProbeRunner::DnsProbeRunner() : result_(UNKNOWN), weak_factory_(this) {}
DnsProbeRunner::~DnsProbeRunner() {}
void DnsProbeRunner::SetClient(scoped_ptr<net::DnsClient> client) {
client_ = client.Pass();
}
void DnsProbeRunner::RunProbe(const base::Closure& callback) {
DCHECK(!callback.is_null());
DCHECK(client_.get());
DCHECK(callback_.is_null());
DCHECK(!transaction_.get());
callback_ = callback;
DnsTransactionFactory* factory = client_->GetTransactionFactory();
if (!factory) {
// If the DnsTransactionFactory is NULL, then the DnsConfig is invalid, so
// the runner can't run a transaction. Return UNKNOWN asynchronously.
result_ = UNKNOWN;
BrowserThread::PostTask(
BrowserThread::IO,
FROM_HERE,
base::Bind(&DnsProbeRunner::CallCallback,
weak_factory_.GetWeakPtr()));
return;
}
transaction_ = factory->CreateTransaction(
kKnownGoodHostname,
net::dns_protocol::kTypeA,
base::Bind(&DnsProbeRunner::OnTransactionComplete,
weak_factory_.GetWeakPtr()),
BoundNetLog());
transaction_->Start();
}
bool DnsProbeRunner::IsRunning() const {
return !callback_.is_null();
}
void DnsProbeRunner::OnTransactionComplete(
DnsTransaction* transaction,
int net_error,
const DnsResponse* response) {
DCHECK(!callback_.is_null());
DCHECK(transaction_.get());
DCHECK_EQ(transaction_.get(), transaction);
result_ = EvaluateResponse(net_error, response);
transaction_.reset();
BrowserThread::PostTask(
BrowserThread::IO,
FROM_HERE,
base::Bind(&DnsProbeRunner::CallCallback,
weak_factory_.GetWeakPtr()));
}
void DnsProbeRunner::CallCallback() {
DCHECK(!callback_.is_null());
DCHECK(!transaction_.get());
// Clear callback in case it starts a new probe immediately.
const base::Closure callback = callback_;
callback_.Reset();
callback.Run();
}
} // namespace chrome_browser_net
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