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host_resolver_impl.cc
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host_resolver_impl.cc
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// 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.
#include "net/dns/host_resolver_impl.h"
#if defined(OS_WIN)
#include <Winsock2.h>
#elif defined(OS_POSIX)
#include <netdb.h>
#endif
#include <cmath>
#include <utility>
#include <vector>
#include "base/basictypes.h"
#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/callback.h"
#include "base/compiler_specific.h"
#include "base/debug/debugger.h"
#include "base/debug/stack_trace.h"
#include "base/message_loop/message_loop_proxy.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/histogram.h"
#include "base/stl_util.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/worker_pool.h"
#include "base/time/time.h"
#include "base/values.h"
#include "net/base/address_family.h"
#include "net/base/address_list.h"
#include "net/base/dns_reloader.h"
#include "net/base/dns_util.h"
#include "net/base/host_port_pair.h"
#include "net/base/net_errors.h"
#include "net/base/net_log.h"
#include "net/base/net_util.h"
#include "net/dns/address_sorter.h"
#include "net/dns/dns_client.h"
#include "net/dns/dns_config_service.h"
#include "net/dns/dns_protocol.h"
#include "net/dns/dns_response.h"
#include "net/dns/dns_transaction.h"
#include "net/dns/host_resolver_proc.h"
#include "net/socket/client_socket_factory.h"
#include "net/udp/datagram_client_socket.h"
#if defined(OS_WIN)
#include "net/base/winsock_init.h"
#endif
namespace net {
namespace {
// Limit the size of hostnames that will be resolved to combat issues in
// some platform's resolvers.
const size_t kMaxHostLength = 4096;
// Default TTL for successful resolutions with ProcTask.
const unsigned kCacheEntryTTLSeconds = 60;
// Default TTL for unsuccessful resolutions with ProcTask.
const unsigned kNegativeCacheEntryTTLSeconds = 0;
// Minimum TTL for successful resolutions with DnsTask.
const unsigned kMinimumTTLSeconds = kCacheEntryTTLSeconds;
// We use a separate histogram name for each platform to facilitate the
// display of error codes by their symbolic name (since each platform has
// different mappings).
const char kOSErrorsForGetAddrinfoHistogramName[] =
#if defined(OS_WIN)
"Net.OSErrorsForGetAddrinfo_Win";
#elif defined(OS_MACOSX)
"Net.OSErrorsForGetAddrinfo_Mac";
#elif defined(OS_LINUX)
"Net.OSErrorsForGetAddrinfo_Linux";
#else
"Net.OSErrorsForGetAddrinfo";
#endif
// Gets a list of the likely error codes that getaddrinfo() can return
// (non-exhaustive). These are the error codes that we will track via
// a histogram.
std::vector<int> GetAllGetAddrinfoOSErrors() {
int os_errors[] = {
#if defined(OS_POSIX)
#if !defined(OS_FREEBSD)
#if !defined(OS_ANDROID)
// EAI_ADDRFAMILY has been declared obsolete in Android's and
// FreeBSD's netdb.h.
EAI_ADDRFAMILY,
#endif
// EAI_NODATA has been declared obsolete in FreeBSD's netdb.h.
EAI_NODATA,
#endif
EAI_AGAIN,
EAI_BADFLAGS,
EAI_FAIL,
EAI_FAMILY,
EAI_MEMORY,
EAI_NONAME,
EAI_SERVICE,
EAI_SOCKTYPE,
EAI_SYSTEM,
#elif defined(OS_WIN)
// See: http://msdn.microsoft.com/en-us/library/ms738520(VS.85).aspx
WSA_NOT_ENOUGH_MEMORY,
WSAEAFNOSUPPORT,
WSAEINVAL,
WSAESOCKTNOSUPPORT,
WSAHOST_NOT_FOUND,
WSANO_DATA,
WSANO_RECOVERY,
WSANOTINITIALISED,
WSATRY_AGAIN,
WSATYPE_NOT_FOUND,
// The following are not in doc, but might be to appearing in results :-(.
WSA_INVALID_HANDLE,
#endif
};
// Ensure all errors are positive, as histogram only tracks positive values.
for (size_t i = 0; i < arraysize(os_errors); ++i) {
os_errors[i] = std::abs(os_errors[i]);
}
return base::CustomHistogram::ArrayToCustomRanges(os_errors,
arraysize(os_errors));
}
enum DnsResolveStatus {
RESOLVE_STATUS_DNS_SUCCESS = 0,
RESOLVE_STATUS_PROC_SUCCESS,
RESOLVE_STATUS_FAIL,
RESOLVE_STATUS_SUSPECT_NETBIOS,
RESOLVE_STATUS_MAX
};
void UmaAsyncDnsResolveStatus(DnsResolveStatus result) {
UMA_HISTOGRAM_ENUMERATION("AsyncDNS.ResolveStatus",
result,
RESOLVE_STATUS_MAX);
}
bool ResemblesNetBIOSName(const std::string& hostname) {
return (hostname.size() < 16) && (hostname.find('.') == std::string::npos);
}
// True if |hostname| ends with either ".local" or ".local.".
bool ResemblesMulticastDNSName(const std::string& hostname) {
DCHECK(!hostname.empty());
const char kSuffix[] = ".local.";
const size_t kSuffixLen = sizeof(kSuffix) - 1;
const size_t kSuffixLenTrimmed = kSuffixLen - 1;
if (hostname[hostname.size() - 1] == '.') {
return hostname.size() > kSuffixLen &&
!hostname.compare(hostname.size() - kSuffixLen, kSuffixLen, kSuffix);
}
return hostname.size() > kSuffixLenTrimmed &&
!hostname.compare(hostname.size() - kSuffixLenTrimmed, kSuffixLenTrimmed,
kSuffix, kSuffixLenTrimmed);
}
// Attempts to connect a UDP socket to |dest|:53.
bool IsGloballyReachable(const IPAddressNumber& dest,
const BoundNetLog& net_log) {
scoped_ptr<DatagramClientSocket> socket(
ClientSocketFactory::GetDefaultFactory()->CreateDatagramClientSocket(
DatagramSocket::DEFAULT_BIND,
RandIntCallback(),
net_log.net_log(),
net_log.source()));
int rv = socket->Connect(IPEndPoint(dest, 53));
if (rv != OK)
return false;
IPEndPoint endpoint;
rv = socket->GetLocalAddress(&endpoint);
if (rv != OK)
return false;
DCHECK(endpoint.GetFamily() == ADDRESS_FAMILY_IPV6);
const IPAddressNumber& address = endpoint.address();
bool is_link_local = (address[0] == 0xFE) && ((address[1] & 0xC0) == 0x80);
if (is_link_local)
return false;
const uint8 kTeredoPrefix[] = { 0x20, 0x01, 0, 0 };
bool is_teredo = std::equal(kTeredoPrefix,
kTeredoPrefix + arraysize(kTeredoPrefix),
address.begin());
if (is_teredo)
return false;
return true;
}
// Provide a common macro to simplify code and readability. We must use a
// macro as the underlying HISTOGRAM macro creates static variables.
#define DNS_HISTOGRAM(name, time) UMA_HISTOGRAM_CUSTOM_TIMES(name, time, \
base::TimeDelta::FromMilliseconds(1), base::TimeDelta::FromHours(1), 100)
// A macro to simplify code and readability.
#define DNS_HISTOGRAM_BY_PRIORITY(basename, priority, time) \
do { \
switch (priority) { \
case HIGHEST: DNS_HISTOGRAM(basename "_HIGHEST", time); break; \
case MEDIUM: DNS_HISTOGRAM(basename "_MEDIUM", time); break; \
case LOW: DNS_HISTOGRAM(basename "_LOW", time); break; \
case LOWEST: DNS_HISTOGRAM(basename "_LOWEST", time); break; \
case IDLE: DNS_HISTOGRAM(basename "_IDLE", time); break; \
default: NOTREACHED(); break; \
} \
DNS_HISTOGRAM(basename, time); \
} while (0)
// Record time from Request creation until a valid DNS response.
void RecordTotalTime(bool had_dns_config,
bool speculative,
base::TimeDelta duration) {
if (had_dns_config) {
if (speculative) {
DNS_HISTOGRAM("AsyncDNS.TotalTime_speculative", duration);
} else {
DNS_HISTOGRAM("AsyncDNS.TotalTime", duration);
}
} else {
if (speculative) {
DNS_HISTOGRAM("DNS.TotalTime_speculative", duration);
} else {
DNS_HISTOGRAM("DNS.TotalTime", duration);
}
}
}
void RecordTTL(base::TimeDelta ttl) {
UMA_HISTOGRAM_CUSTOM_TIMES("AsyncDNS.TTL", ttl,
base::TimeDelta::FromSeconds(1),
base::TimeDelta::FromDays(1), 100);
}
bool ConfigureAsyncDnsNoFallbackFieldTrial() {
const bool kDefault = false;
// Configure the AsyncDns field trial as follows:
// groups AsyncDnsNoFallbackA and AsyncDnsNoFallbackB: return true,
// groups AsyncDnsA and AsyncDnsB: return false,
// groups SystemDnsA and SystemDnsB: return false,
// otherwise (trial absent): return default.
std::string group_name = base::FieldTrialList::FindFullName("AsyncDns");
if (!group_name.empty())
return StartsWithASCII(group_name, "AsyncDnsNoFallback", false);
return kDefault;
}
//-----------------------------------------------------------------------------
AddressList EnsurePortOnAddressList(const AddressList& list, uint16 port) {
if (list.empty() || list.front().port() == port)
return list;
return AddressList::CopyWithPort(list, port);
}
// Returns true if |addresses| contains only IPv4 loopback addresses.
bool IsAllIPv4Loopback(const AddressList& addresses) {
for (unsigned i = 0; i < addresses.size(); ++i) {
const IPAddressNumber& address = addresses[i].address();
switch (addresses[i].GetFamily()) {
case ADDRESS_FAMILY_IPV4:
if (address[0] != 127)
return false;
break;
case ADDRESS_FAMILY_IPV6:
return false;
default:
NOTREACHED();
return false;
}
}
return true;
}
// Creates NetLog parameters when the resolve failed.
base::Value* NetLogProcTaskFailedCallback(uint32 attempt_number,
int net_error,
int os_error,
NetLog::LogLevel /* log_level */) {
base::DictionaryValue* dict = new base::DictionaryValue();
if (attempt_number)
dict->SetInteger("attempt_number", attempt_number);
dict->SetInteger("net_error", net_error);
if (os_error) {
dict->SetInteger("os_error", os_error);
#if defined(OS_POSIX)
dict->SetString("os_error_string", gai_strerror(os_error));
#elif defined(OS_WIN)
// Map the error code to a human-readable string.
LPWSTR error_string = NULL;
int size = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM,
0, // Use the internal message table.
os_error,
0, // Use default language.
(LPWSTR)&error_string,
0, // Buffer size.
0); // Arguments (unused).
dict->SetString("os_error_string", base::WideToUTF8(error_string));
LocalFree(error_string);
#endif
}
return dict;
}
// Creates NetLog parameters when the DnsTask failed.
base::Value* NetLogDnsTaskFailedCallback(int net_error,
int dns_error,
NetLog::LogLevel /* log_level */) {
base::DictionaryValue* dict = new base::DictionaryValue();
dict->SetInteger("net_error", net_error);
if (dns_error)
dict->SetInteger("dns_error", dns_error);
return dict;
};
// Creates NetLog parameters containing the information in a RequestInfo object,
// along with the associated NetLog::Source.
base::Value* NetLogRequestInfoCallback(const NetLog::Source& source,
const HostResolver::RequestInfo* info,
NetLog::LogLevel /* log_level */) {
base::DictionaryValue* dict = new base::DictionaryValue();
source.AddToEventParameters(dict);
dict->SetString("host", info->host_port_pair().ToString());
dict->SetInteger("address_family",
static_cast<int>(info->address_family()));
dict->SetBoolean("allow_cached_response", info->allow_cached_response());
dict->SetBoolean("is_speculative", info->is_speculative());
return dict;
}
// Creates NetLog parameters for the creation of a HostResolverImpl::Job.
base::Value* NetLogJobCreationCallback(const NetLog::Source& source,
const std::string* host,
NetLog::LogLevel /* log_level */) {
base::DictionaryValue* dict = new base::DictionaryValue();
source.AddToEventParameters(dict);
dict->SetString("host", *host);
return dict;
}
// Creates NetLog parameters for HOST_RESOLVER_IMPL_JOB_ATTACH/DETACH events.
base::Value* NetLogJobAttachCallback(const NetLog::Source& source,
RequestPriority priority,
NetLog::LogLevel /* log_level */) {
base::DictionaryValue* dict = new base::DictionaryValue();
source.AddToEventParameters(dict);
dict->SetString("priority", RequestPriorityToString(priority));
return dict;
}
// Creates NetLog parameters for the DNS_CONFIG_CHANGED event.
base::Value* NetLogDnsConfigCallback(const DnsConfig* config,
NetLog::LogLevel /* log_level */) {
return config->ToValue();
}
// The logging routines are defined here because some requests are resolved
// without a Request object.
// Logs when a request has just been started.
void LogStartRequest(const BoundNetLog& source_net_log,
const BoundNetLog& request_net_log,
const HostResolver::RequestInfo& info) {
source_net_log.BeginEvent(
NetLog::TYPE_HOST_RESOLVER_IMPL,
request_net_log.source().ToEventParametersCallback());
request_net_log.BeginEvent(
NetLog::TYPE_HOST_RESOLVER_IMPL_REQUEST,
base::Bind(&NetLogRequestInfoCallback, source_net_log.source(), &info));
}
// Logs when a request has just completed (before its callback is run).
void LogFinishRequest(const BoundNetLog& source_net_log,
const BoundNetLog& request_net_log,
const HostResolver::RequestInfo& info,
int net_error) {
request_net_log.EndEventWithNetErrorCode(
NetLog::TYPE_HOST_RESOLVER_IMPL_REQUEST, net_error);
source_net_log.EndEvent(NetLog::TYPE_HOST_RESOLVER_IMPL);
}
// Logs when a request has been cancelled.
void LogCancelRequest(const BoundNetLog& source_net_log,
const BoundNetLog& request_net_log,
const HostResolverImpl::RequestInfo& info) {
request_net_log.AddEvent(NetLog::TYPE_CANCELLED);
request_net_log.EndEvent(NetLog::TYPE_HOST_RESOLVER_IMPL_REQUEST);
source_net_log.EndEvent(NetLog::TYPE_HOST_RESOLVER_IMPL);
}
//-----------------------------------------------------------------------------
// Keeps track of the highest priority.
class PriorityTracker {
public:
explicit PriorityTracker(RequestPriority initial_priority)
: highest_priority_(initial_priority), total_count_(0) {
memset(counts_, 0, sizeof(counts_));
}
RequestPriority highest_priority() const {
return highest_priority_;
}
size_t total_count() const {
return total_count_;
}
void Add(RequestPriority req_priority) {
++total_count_;
++counts_[req_priority];
if (highest_priority_ < req_priority)
highest_priority_ = req_priority;
}
void Remove(RequestPriority req_priority) {
DCHECK_GT(total_count_, 0u);
DCHECK_GT(counts_[req_priority], 0u);
--total_count_;
--counts_[req_priority];
size_t i;
for (i = highest_priority_; i > MINIMUM_PRIORITY && !counts_[i]; --i);
highest_priority_ = static_cast<RequestPriority>(i);
// In absence of requests, default to MINIMUM_PRIORITY.
if (total_count_ == 0)
DCHECK_EQ(MINIMUM_PRIORITY, highest_priority_);
}
private:
RequestPriority highest_priority_;
size_t total_count_;
size_t counts_[NUM_PRIORITIES];
};
} // namespace
//-----------------------------------------------------------------------------
const unsigned HostResolverImpl::kMaximumDnsFailures = 16;
// Holds the data for a request that could not be completed synchronously.
// It is owned by a Job. Canceled Requests are only marked as canceled rather
// than removed from the Job's |requests_| list.
class HostResolverImpl::Request {
public:
Request(const BoundNetLog& source_net_log,
const BoundNetLog& request_net_log,
const RequestInfo& info,
RequestPriority priority,
const CompletionCallback& callback,
AddressList* addresses)
: source_net_log_(source_net_log),
request_net_log_(request_net_log),
info_(info),
priority_(priority),
job_(NULL),
callback_(callback),
addresses_(addresses),
request_time_(base::TimeTicks::Now()) {}
// Mark the request as canceled.
void MarkAsCanceled() {
job_ = NULL;
addresses_ = NULL;
callback_.Reset();
}
bool was_canceled() const {
return callback_.is_null();
}
void set_job(Job* job) {
DCHECK(job);
// Identify which job the request is waiting on.
job_ = job;
}
// Prepare final AddressList and call completion callback.
void OnComplete(int error, const AddressList& addr_list) {
DCHECK(!was_canceled());
if (error == OK)
*addresses_ = EnsurePortOnAddressList(addr_list, info_.port());
CompletionCallback callback = callback_;
MarkAsCanceled();
callback.Run(error);
}
Job* job() const {
return job_;
}
// NetLog for the source, passed in HostResolver::Resolve.
const BoundNetLog& source_net_log() {
return source_net_log_;
}
// NetLog for this request.
const BoundNetLog& request_net_log() {
return request_net_log_;
}
const RequestInfo& info() const {
return info_;
}
RequestPriority priority() const { return priority_; }
base::TimeTicks request_time() const { return request_time_; }
private:
BoundNetLog source_net_log_;
BoundNetLog request_net_log_;
// The request info that started the request.
const RequestInfo info_;
// TODO(akalin): Support reprioritization.
const RequestPriority priority_;
// The resolve job that this request is dependent on.
Job* job_;
// The user's callback to invoke when the request completes.
CompletionCallback callback_;
// The address list to save result into.
AddressList* addresses_;
const base::TimeTicks request_time_;
DISALLOW_COPY_AND_ASSIGN(Request);
};
//------------------------------------------------------------------------------
// Calls HostResolverProc on the WorkerPool. Performs retries if necessary.
//
// Whenever we try to resolve the host, we post a delayed task to check if host
// resolution (OnLookupComplete) is completed or not. If the original attempt
// hasn't completed, then we start another attempt for host resolution. We take
// the results from the first attempt that finishes and ignore the results from
// all other attempts.
//
// TODO(szym): Move to separate source file for testing and mocking.
//
class HostResolverImpl::ProcTask
: public base::RefCountedThreadSafe<HostResolverImpl::ProcTask> {
public:
typedef base::Callback<void(int net_error,
const AddressList& addr_list)> Callback;
ProcTask(const Key& key,
const ProcTaskParams& params,
const Callback& callback,
const BoundNetLog& job_net_log)
: key_(key),
params_(params),
callback_(callback),
origin_loop_(base::MessageLoopProxy::current()),
attempt_number_(0),
completed_attempt_number_(0),
completed_attempt_error_(ERR_UNEXPECTED),
had_non_speculative_request_(false),
net_log_(job_net_log) {
if (!params_.resolver_proc.get())
params_.resolver_proc = HostResolverProc::GetDefault();
// If default is unset, use the system proc.
if (!params_.resolver_proc.get())
params_.resolver_proc = new SystemHostResolverProc();
}
void Start() {
DCHECK(origin_loop_->BelongsToCurrentThread());
net_log_.BeginEvent(NetLog::TYPE_HOST_RESOLVER_IMPL_PROC_TASK);
StartLookupAttempt();
}
// Cancels this ProcTask. It will be orphaned. Any outstanding resolve
// attempts running on worker threads will continue running. Only once all the
// attempts complete will the final reference to this ProcTask be released.
void Cancel() {
DCHECK(origin_loop_->BelongsToCurrentThread());
if (was_canceled() || was_completed())
return;
callback_.Reset();
net_log_.EndEvent(NetLog::TYPE_HOST_RESOLVER_IMPL_PROC_TASK);
}
void set_had_non_speculative_request() {
DCHECK(origin_loop_->BelongsToCurrentThread());
had_non_speculative_request_ = true;
}
bool was_canceled() const {
DCHECK(origin_loop_->BelongsToCurrentThread());
return callback_.is_null();
}
bool was_completed() const {
DCHECK(origin_loop_->BelongsToCurrentThread());
return completed_attempt_number_ > 0;
}
private:
friend class base::RefCountedThreadSafe<ProcTask>;
~ProcTask() {}
void StartLookupAttempt() {
DCHECK(origin_loop_->BelongsToCurrentThread());
base::TimeTicks start_time = base::TimeTicks::Now();
++attempt_number_;
// Dispatch the lookup attempt to a worker thread.
if (!base::WorkerPool::PostTask(
FROM_HERE,
base::Bind(&ProcTask::DoLookup, this, start_time, attempt_number_),
true)) {
NOTREACHED();
// Since we could be running within Resolve() right now, we can't just
// call OnLookupComplete(). Instead we must wait until Resolve() has
// returned (IO_PENDING).
origin_loop_->PostTask(
FROM_HERE,
base::Bind(&ProcTask::OnLookupComplete, this, AddressList(),
start_time, attempt_number_, ERR_UNEXPECTED, 0));
return;
}
net_log_.AddEvent(
NetLog::TYPE_HOST_RESOLVER_IMPL_ATTEMPT_STARTED,
NetLog::IntegerCallback("attempt_number", attempt_number_));
// If we don't get the results within a given time, RetryIfNotComplete
// will start a new attempt on a different worker thread if none of our
// outstanding attempts have completed yet.
if (attempt_number_ <= params_.max_retry_attempts) {
origin_loop_->PostDelayedTask(
FROM_HERE,
base::Bind(&ProcTask::RetryIfNotComplete, this),
params_.unresponsive_delay);
}
}
// WARNING: This code runs inside a worker pool. The shutdown code cannot
// wait for it to finish, so we must be very careful here about using other
// objects (like MessageLoops, Singletons, etc). During shutdown these objects
// may no longer exist. Multiple DoLookups() could be running in parallel, so
// any state inside of |this| must not mutate .
void DoLookup(const base::TimeTicks& start_time,
const uint32 attempt_number) {
AddressList results;
int os_error = 0;
// Running on the worker thread
int error = params_.resolver_proc->Resolve(key_.hostname,
key_.address_family,
key_.host_resolver_flags,
&results,
&os_error);
origin_loop_->PostTask(
FROM_HERE,
base::Bind(&ProcTask::OnLookupComplete, this, results, start_time,
attempt_number, error, os_error));
}
// Makes next attempt if DoLookup() has not finished (runs on origin thread).
void RetryIfNotComplete() {
DCHECK(origin_loop_->BelongsToCurrentThread());
if (was_completed() || was_canceled())
return;
params_.unresponsive_delay *= params_.retry_factor;
StartLookupAttempt();
}
// Callback for when DoLookup() completes (runs on origin thread).
void OnLookupComplete(const AddressList& results,
const base::TimeTicks& start_time,
const uint32 attempt_number,
int error,
const int os_error) {
DCHECK(origin_loop_->BelongsToCurrentThread());
// If results are empty, we should return an error.
bool empty_list_on_ok = (error == OK && results.empty());
UMA_HISTOGRAM_BOOLEAN("DNS.EmptyAddressListAndNoError", empty_list_on_ok);
if (empty_list_on_ok)
error = ERR_NAME_NOT_RESOLVED;
bool was_retry_attempt = attempt_number > 1;
// Ideally the following code would be part of host_resolver_proc.cc,
// however it isn't safe to call NetworkChangeNotifier from worker threads.
// So we do it here on the IO thread instead.
if (error != OK && NetworkChangeNotifier::IsOffline())
error = ERR_INTERNET_DISCONNECTED;
// If this is the first attempt that is finishing later, then record data
// for the first attempt. Won't contaminate with retry attempt's data.
if (!was_retry_attempt)
RecordPerformanceHistograms(start_time, error, os_error);
RecordAttemptHistograms(start_time, attempt_number, error, os_error);
if (was_canceled())
return;
NetLog::ParametersCallback net_log_callback;
if (error != OK) {
net_log_callback = base::Bind(&NetLogProcTaskFailedCallback,
attempt_number,
error,
os_error);
} else {
net_log_callback = NetLog::IntegerCallback("attempt_number",
attempt_number);
}
net_log_.AddEvent(NetLog::TYPE_HOST_RESOLVER_IMPL_ATTEMPT_FINISHED,
net_log_callback);
if (was_completed())
return;
// Copy the results from the first worker thread that resolves the host.
results_ = results;
completed_attempt_number_ = attempt_number;
completed_attempt_error_ = error;
if (was_retry_attempt) {
// If retry attempt finishes before 1st attempt, then get stats on how
// much time is saved by having spawned an extra attempt.
retry_attempt_finished_time_ = base::TimeTicks::Now();
}
if (error != OK) {
net_log_callback = base::Bind(&NetLogProcTaskFailedCallback,
0, error, os_error);
} else {
net_log_callback = results_.CreateNetLogCallback();
}
net_log_.EndEvent(NetLog::TYPE_HOST_RESOLVER_IMPL_PROC_TASK,
net_log_callback);
callback_.Run(error, results_);
}
void RecordPerformanceHistograms(const base::TimeTicks& start_time,
const int error,
const int os_error) const {
DCHECK(origin_loop_->BelongsToCurrentThread());
enum Category { // Used in HISTOGRAM_ENUMERATION.
RESOLVE_SUCCESS,
RESOLVE_FAIL,
RESOLVE_SPECULATIVE_SUCCESS,
RESOLVE_SPECULATIVE_FAIL,
RESOLVE_MAX, // Bounding value.
};
int category = RESOLVE_MAX; // Illegal value for later DCHECK only.
base::TimeDelta duration = base::TimeTicks::Now() - start_time;
if (error == OK) {
if (had_non_speculative_request_) {
category = RESOLVE_SUCCESS;
DNS_HISTOGRAM("DNS.ResolveSuccess", duration);
} else {
category = RESOLVE_SPECULATIVE_SUCCESS;
DNS_HISTOGRAM("DNS.ResolveSpeculativeSuccess", duration);
}
// Log DNS lookups based on |address_family|. This will help us determine
// if IPv4 or IPv4/6 lookups are faster or slower.
switch(key_.address_family) {
case ADDRESS_FAMILY_IPV4:
DNS_HISTOGRAM("DNS.ResolveSuccess_FAMILY_IPV4", duration);
break;
case ADDRESS_FAMILY_IPV6:
DNS_HISTOGRAM("DNS.ResolveSuccess_FAMILY_IPV6", duration);
break;
case ADDRESS_FAMILY_UNSPECIFIED:
DNS_HISTOGRAM("DNS.ResolveSuccess_FAMILY_UNSPEC", duration);
break;
}
} else {
if (had_non_speculative_request_) {
category = RESOLVE_FAIL;
DNS_HISTOGRAM("DNS.ResolveFail", duration);
} else {
category = RESOLVE_SPECULATIVE_FAIL;
DNS_HISTOGRAM("DNS.ResolveSpeculativeFail", duration);
}
// Log DNS lookups based on |address_family|. This will help us determine
// if IPv4 or IPv4/6 lookups are faster or slower.
switch(key_.address_family) {
case ADDRESS_FAMILY_IPV4:
DNS_HISTOGRAM("DNS.ResolveFail_FAMILY_IPV4", duration);
break;
case ADDRESS_FAMILY_IPV6:
DNS_HISTOGRAM("DNS.ResolveFail_FAMILY_IPV6", duration);
break;
case ADDRESS_FAMILY_UNSPECIFIED:
DNS_HISTOGRAM("DNS.ResolveFail_FAMILY_UNSPEC", duration);
break;
}
UMA_HISTOGRAM_CUSTOM_ENUMERATION(kOSErrorsForGetAddrinfoHistogramName,
std::abs(os_error),
GetAllGetAddrinfoOSErrors());
}
DCHECK_LT(category, static_cast<int>(RESOLVE_MAX)); // Be sure it was set.
UMA_HISTOGRAM_ENUMERATION("DNS.ResolveCategory", category, RESOLVE_MAX);
}
void RecordAttemptHistograms(const base::TimeTicks& start_time,
const uint32 attempt_number,
const int error,
const int os_error) const {
DCHECK(origin_loop_->BelongsToCurrentThread());
bool first_attempt_to_complete =
completed_attempt_number_ == attempt_number;
bool is_first_attempt = (attempt_number == 1);
if (first_attempt_to_complete) {
// If this was first attempt to complete, then record the resolution
// status of the attempt.
if (completed_attempt_error_ == OK) {
UMA_HISTOGRAM_ENUMERATION(
"DNS.AttemptFirstSuccess", attempt_number, 100);
} else {
UMA_HISTOGRAM_ENUMERATION(
"DNS.AttemptFirstFailure", attempt_number, 100);
}
}
if (error == OK)
UMA_HISTOGRAM_ENUMERATION("DNS.AttemptSuccess", attempt_number, 100);
else
UMA_HISTOGRAM_ENUMERATION("DNS.AttemptFailure", attempt_number, 100);
// If first attempt didn't finish before retry attempt, then calculate stats
// on how much time is saved by having spawned an extra attempt.
if (!first_attempt_to_complete && is_first_attempt && !was_canceled()) {
DNS_HISTOGRAM("DNS.AttemptTimeSavedByRetry",
base::TimeTicks::Now() - retry_attempt_finished_time_);
}
if (was_canceled() || !first_attempt_to_complete) {
// Count those attempts which completed after the job was already canceled
// OR after the job was already completed by an earlier attempt (so in
// effect).
UMA_HISTOGRAM_ENUMERATION("DNS.AttemptDiscarded", attempt_number, 100);
// Record if job is canceled.
if (was_canceled())
UMA_HISTOGRAM_ENUMERATION("DNS.AttemptCancelled", attempt_number, 100);
}
base::TimeDelta duration = base::TimeTicks::Now() - start_time;
if (error == OK)
DNS_HISTOGRAM("DNS.AttemptSuccessDuration", duration);
else
DNS_HISTOGRAM("DNS.AttemptFailDuration", duration);
}
// Set on the origin thread, read on the worker thread.
Key key_;
// Holds an owning reference to the HostResolverProc that we are going to use.
// This may not be the current resolver procedure by the time we call
// ResolveAddrInfo, but that's OK... we'll use it anyways, and the owning
// reference ensures that it remains valid until we are done.
ProcTaskParams params_;
// The listener to the results of this ProcTask.
Callback callback_;
// Used to post ourselves onto the origin thread.
scoped_refptr<base::MessageLoopProxy> origin_loop_;
// Keeps track of the number of attempts we have made so far to resolve the
// host. Whenever we start an attempt to resolve the host, we increase this
// number.
uint32 attempt_number_;
// The index of the attempt which finished first (or 0 if the job is still in
// progress).
uint32 completed_attempt_number_;
// The result (a net error code) from the first attempt to complete.
int completed_attempt_error_;
// The time when retry attempt was finished.
base::TimeTicks retry_attempt_finished_time_;
// True if a non-speculative request was ever attached to this job
// (regardless of whether or not it was later canceled.
// This boolean is used for histogramming the duration of jobs used to
// service non-speculative requests.
bool had_non_speculative_request_;
AddressList results_;
BoundNetLog net_log_;
DISALLOW_COPY_AND_ASSIGN(ProcTask);
};
//-----------------------------------------------------------------------------
// Wraps a call to HaveOnlyLoopbackAddresses to be executed on the WorkerPool as
// it takes 40-100ms and should not block initialization.
class HostResolverImpl::LoopbackProbeJob {
public:
explicit LoopbackProbeJob(const base::WeakPtr<HostResolverImpl>& resolver)
: resolver_(resolver),
result_(false) {
DCHECK(resolver.get());
const bool kIsSlow = true;
base::WorkerPool::PostTaskAndReply(
FROM_HERE,
base::Bind(&LoopbackProbeJob::DoProbe, base::Unretained(this)),
base::Bind(&LoopbackProbeJob::OnProbeComplete, base::Owned(this)),
kIsSlow);
}
virtual ~LoopbackProbeJob() {}
private:
// Runs on worker thread.
void DoProbe() {
result_ = HaveOnlyLoopbackAddresses();
}
void OnProbeComplete() {
if (!resolver_.get())
return;
resolver_->SetHaveOnlyLoopbackAddresses(result_);
}
// Used/set only on origin thread.
base::WeakPtr<HostResolverImpl> resolver_;
bool result_;
DISALLOW_COPY_AND_ASSIGN(LoopbackProbeJob);
};
//-----------------------------------------------------------------------------
// Resolves the hostname using DnsTransaction.
// TODO(szym): This could be moved to separate source file as well.
class HostResolverImpl::DnsTask : public base::SupportsWeakPtr<DnsTask> {
public:
class Delegate {
public:
virtual void OnDnsTaskComplete(base::TimeTicks start_time,
int net_error,
const AddressList& addr_list,
base::TimeDelta ttl) = 0;
// Called when the first of two jobs succeeds. If the first completed
// transaction fails, this is not called. Also not called when the DnsTask
// only needs to run one transaction.
virtual void OnFirstDnsTransactionComplete() = 0;
protected:
Delegate() {}
virtual ~Delegate() {}
};
DnsTask(DnsClient* client,
const Key& key,
Delegate* delegate,
const BoundNetLog& job_net_log)
: client_(client),
key_(key),
delegate_(delegate),
net_log_(job_net_log),
num_completed_transactions_(0),
task_start_time_(base::TimeTicks::Now()) {
DCHECK(client);
DCHECK(delegate_);
}