net/socket/transport_client_socket_pool.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/socket/transport_client_socket_pool.h"
   6
   7 #include <algorithm>
   8
   9 #include "base/compiler_specific.h"
  10 #include "base/lazy_instance.h"
  11 #include "base/logging.h"
  12 #include "base/message_loop/message_loop.h"
  13 #include "base/metrics/histogram.h"
  14 #include "base/strings/string_util.h"
  15 #include "base/synchronization/lock.h"
  16 #include "base/time/time.h"
  17 #include "base/values.h"
  18 #include "net/base/ip_endpoint.h"
  19 #include "net/base/net_errors.h"
  20 #include "net/base/net_log.h"
  21 #include "net/socket/client_socket_factory.h"
  22 #include "net/socket/client_socket_handle.h"
  23 #include "net/socket/client_socket_pool_base.h"
  24 #include "net/socket/socket_net_log_params.h"
  25 #include "net/socket/tcp_client_socket.h"
  26
  27 using base::TimeDelta;
  28
  29 namespace net {
  30
  31 // TODO(willchan): Base this off RTT instead of statically setting it. Note we
  32 // choose a timeout that is different from the backup connect job timer so they
  33 // don't synchronize.
  34 const int TransportConnectJobHelper::kIPv6FallbackTimerInMs = 300;
  35
  36 namespace {
  37
  38 // Returns true iff all addresses in |list| are in the IPv6 family.
  39 bool AddressListOnlyContainsIPv6(const AddressList& list) {
  40   DCHECK(!list.empty());
  41   for (AddressList::const_iterator iter = list.begin(); iter != list.end();
  42        ++iter) {
  43     if (iter->GetFamily() != ADDRESS_FAMILY_IPV6)
  44       return false;
  45   }
  46   return true;
  47 }
  48
  49 }  // namespace
  50
  51 // This lock protects |g_last_connect_time|.
  52 static base::LazyInstance<base::Lock>::Leaky
  53     g_last_connect_time_lock = LAZY_INSTANCE_INITIALIZER;
  54
  55 // |g_last_connect_time| has the last time a connect() call is made.
  56 static base::LazyInstance<base::TimeTicks>::Leaky
  57     g_last_connect_time = LAZY_INSTANCE_INITIALIZER;
  58
  59 TransportSocketParams::TransportSocketParams(
  60     const HostPortPair& host_port_pair,
  61     bool disable_resolver_cache,
  62     bool ignore_limits,
  63     const OnHostResolutionCallback& host_resolution_callback,
  64     CombineConnectAndWritePolicy combine_connect_and_write_if_supported)
  65     : destination_(host_port_pair),
  66       ignore_limits_(ignore_limits),
  67       host_resolution_callback_(host_resolution_callback),
  68       combine_connect_and_write_(combine_connect_and_write_if_supported) {
  69   if (disable_resolver_cache)
  70     destination_.set_allow_cached_response(false);
  71   // combine_connect_and_write currently translates to TCP FastOpen.
  72   // Enable TCP FastOpen if user wants it.
  73   if (combine_connect_and_write_ == COMBINE_CONNECT_AND_WRITE_DEFAULT) {
  74     IsTCPFastOpenUserEnabled() ? combine_connect_and_write_ =
  75         COMBINE_CONNECT_AND_WRITE_DESIRED :
  76         COMBINE_CONNECT_AND_WRITE_PROHIBITED;
  77   }
  78 }
  79
  80 TransportSocketParams::~TransportSocketParams() {}
  81
  82 // TransportConnectJobs will time out after this many seconds.  Note this is
  83 // the total time, including both host resolution and TCP connect() times.
  84 //
  85 // TODO(eroman): The use of this constant needs to be re-evaluated. The time
  86 // needed for TCPClientSocketXXX::Connect() can be arbitrarily long, since
  87 // the address list may contain many alternatives, and most of those may
  88 // timeout. Even worse, the per-connect timeout threshold varies greatly
  89 // between systems (anywhere from 20 seconds to 190 seconds).
  90 // See comment #12 at http://crbug.com/23364 for specifics.
  91 static const int kTransportConnectJobTimeoutInSeconds = 240;  // 4 minutes.
  92
  93 TransportConnectJobHelper::TransportConnectJobHelper(
  94     const scoped_refptr<TransportSocketParams>& params,
  95     ClientSocketFactory* client_socket_factory,
  96     HostResolver* host_resolver,
  97     LoadTimingInfo::ConnectTiming* connect_timing)
  98     : params_(params),
  99       client_socket_factory_(client_socket_factory),
 100       resolver_(host_resolver),
 101       next_state_(STATE_NONE),
 102       connect_timing_(connect_timing) {}
 103
 104 TransportConnectJobHelper::~TransportConnectJobHelper() {}
 105
 106 int TransportConnectJobHelper::DoResolveHost(RequestPriority priority,
 107                                              const BoundNetLog& net_log) {
 108   next_state_ = STATE_RESOLVE_HOST_COMPLETE;
 109   connect_timing_->dns_start = base::TimeTicks::Now();
 110
 111   return resolver_.Resolve(
 112       params_->destination(), priority, &addresses_, on_io_complete_, net_log);
 113 }
 114
 115 int TransportConnectJobHelper::DoResolveHostComplete(
 116     int result,
 117     const BoundNetLog& net_log) {
 118   connect_timing_->dns_end = base::TimeTicks::Now();
 119   // Overwrite connection start time, since for connections that do not go
 120   // through proxies, |connect_start| should not include dns lookup time.
 121   connect_timing_->connect_start = connect_timing_->dns_end;
 122
 123   if (result == OK) {
 124     // Invoke callback, and abort if it fails.
 125     if (!params_->host_resolution_callback().is_null())
 126       result = params_->host_resolution_callback().Run(addresses_, net_log);
 127
 128     if (result == OK)
 129       next_state_ = STATE_TRANSPORT_CONNECT;
 130   }
 131   return result;
 132 }
 133
 134 base::TimeDelta TransportConnectJobHelper::HistogramDuration(
 135     ConnectionLatencyHistogram race_result) {
 136   DCHECK(!connect_timing_->connect_start.is_null());
 137   DCHECK(!connect_timing_->dns_start.is_null());
 138   base::TimeTicks now = base::TimeTicks::Now();
 139   base::TimeDelta total_duration = now - connect_timing_->dns_start;
 140   UMA_HISTOGRAM_CUSTOM_TIMES("Net.DNS_Resolution_And_TCP_Connection_Latency2",
 141                              total_duration,
 142                              base::TimeDelta::FromMilliseconds(1),
 143                              base::TimeDelta::FromMinutes(10),
 144                              100);
 145
 146   base::TimeDelta connect_duration = now - connect_timing_->connect_start;
 147   UMA_HISTOGRAM_CUSTOM_TIMES("Net.TCP_Connection_Latency",
 148                              connect_duration,
 149                              base::TimeDelta::FromMilliseconds(1),
 150                              base::TimeDelta::FromMinutes(10),
 151                              100);
 152
 153   switch (race_result) {
 154     case CONNECTION_LATENCY_IPV4_WINS_RACE:
 155       UMA_HISTOGRAM_CUSTOM_TIMES("Net.TCP_Connection_Latency_IPv4_Wins_Race",
 156                                  connect_duration,
 157                                  base::TimeDelta::FromMilliseconds(1),
 158                                  base::TimeDelta::FromMinutes(10),
 159                                  100);
 160       break;
 161
 162     case CONNECTION_LATENCY_IPV4_NO_RACE:
 163       UMA_HISTOGRAM_CUSTOM_TIMES("Net.TCP_Connection_Latency_IPv4_No_Race",
 164                                  connect_duration,
 165                                  base::TimeDelta::FromMilliseconds(1),
 166                                  base::TimeDelta::FromMinutes(10),
 167                                  100);
 168       break;
 169
 170     case CONNECTION_LATENCY_IPV6_RACEABLE:
 171       UMA_HISTOGRAM_CUSTOM_TIMES("Net.TCP_Connection_Latency_IPv6_Raceable",
 172                                  connect_duration,
 173                                  base::TimeDelta::FromMilliseconds(1),
 174                                  base::TimeDelta::FromMinutes(10),
 175                                  100);
 176       break;
 177
 178     case CONNECTION_LATENCY_IPV6_SOLO:
 179       UMA_HISTOGRAM_CUSTOM_TIMES("Net.TCP_Connection_Latency_IPv6_Solo",
 180                                  connect_duration,
 181                                  base::TimeDelta::FromMilliseconds(1),
 182                                  base::TimeDelta::FromMinutes(10),
 183                                  100);
 184       break;
 185
 186     default:
 187       NOTREACHED();
 188       break;
 189   }
 190
 191   return connect_duration;
 192 }
 193
 194 TransportConnectJob::TransportConnectJob(
 195     const std::string& group_name,
 196     RequestPriority priority,
 197     const scoped_refptr<TransportSocketParams>& params,
 198     base::TimeDelta timeout_duration,
 199     ClientSocketFactory* client_socket_factory,
 200     HostResolver* host_resolver,
 201     Delegate* delegate,
 202     NetLog* net_log)
 203     : ConnectJob(group_name, timeout_duration, priority, delegate,
 204                  BoundNetLog::Make(net_log, NetLog::SOURCE_CONNECT_JOB)),
 205       helper_(params, client_socket_factory, host_resolver, &connect_timing_),
 206       interval_between_connects_(CONNECT_INTERVAL_GT_20MS) {
 207   helper_.SetOnIOComplete(this);
 208 }
 209
 210 TransportConnectJob::~TransportConnectJob() {
 211   // We don't worry about cancelling the host resolution and TCP connect, since
 212   // ~SingleRequestHostResolver and ~StreamSocket will take care of it.
 213 }
 214
 215 LoadState TransportConnectJob::GetLoadState() const {
 216   switch (helper_.next_state()) {
 217     case TransportConnectJobHelper::STATE_RESOLVE_HOST:
 218     case TransportConnectJobHelper::STATE_RESOLVE_HOST_COMPLETE:
 219       return LOAD_STATE_RESOLVING_HOST;
 220     case TransportConnectJobHelper::STATE_TRANSPORT_CONNECT:
 221     case TransportConnectJobHelper::STATE_TRANSPORT_CONNECT_COMPLETE:
 222       return LOAD_STATE_CONNECTING;
 223     case TransportConnectJobHelper::STATE_NONE:
 224       return LOAD_STATE_IDLE;
 225   }
 226   NOTREACHED();
 227   return LOAD_STATE_IDLE;
 228 }
 229
 230 // static
 231 void TransportConnectJob::MakeAddressListStartWithIPv4(AddressList* list) {
 232   for (AddressList::iterator i = list->begin(); i != list->end(); ++i) {
 233     if (i->GetFamily() == ADDRESS_FAMILY_IPV4) {
 234       std::rotate(list->begin(), i, list->end());
 235       break;
 236     }
 237   }
 238 }
 239
 240 int TransportConnectJob::DoResolveHost() {
 241   return helper_.DoResolveHost(priority(), net_log());
 242 }
 243
 244 int TransportConnectJob::DoResolveHostComplete(int result) {
 245   return helper_.DoResolveHostComplete(result, net_log());
 246 }
 247
 248 int TransportConnectJob::DoTransportConnect() {
 249   base::TimeTicks now = base::TimeTicks::Now();
 250   base::TimeTicks last_connect_time;
 251   {
 252     base::AutoLock lock(g_last_connect_time_lock.Get());
 253     last_connect_time = g_last_connect_time.Get();
 254     *g_last_connect_time.Pointer() = now;
 255   }
 256   if (last_connect_time.is_null()) {
 257     interval_between_connects_ = CONNECT_INTERVAL_GT_20MS;
 258   } else {
 259     int64 interval = (now - last_connect_time).InMilliseconds();
 260     if (interval <= 10)
 261       interval_between_connects_ = CONNECT_INTERVAL_LE_10MS;
 262     else if (interval <= 20)
 263       interval_between_connects_ = CONNECT_INTERVAL_LE_20MS;
 264     else
 265       interval_between_connects_ = CONNECT_INTERVAL_GT_20MS;
 266   }
 267
 268   helper_.set_next_state(
 269       TransportConnectJobHelper::STATE_TRANSPORT_CONNECT_COMPLETE);
 270   transport_socket_ =
 271       helper_.client_socket_factory()->CreateTransportClientSocket(
 272           helper_.addresses(), net_log().net_log(), net_log().source());
 273
 274   // If the list contains IPv6 and IPv4 addresses, the first address will
 275   // be IPv6, and the IPv4 addresses will be tried as fallback addresses,
 276   // per "Happy Eyeballs" (RFC 6555).
 277   bool try_ipv6_connect_with_ipv4_fallback =
 278       helper_.addresses().front().GetFamily() == ADDRESS_FAMILY_IPV6 &&
 279       !AddressListOnlyContainsIPv6(helper_.addresses());
 280
 281   // Enable TCP FastOpen if indicated by transport socket params.
 282   // Note: We currently do not turn on TCP FastOpen for destinations where
 283   // we try a TCP connect over IPv6 with fallback to IPv4.
 284   if (!try_ipv6_connect_with_ipv4_fallback &&
 285       helper_.params()->combine_connect_and_write() ==
 286           TransportSocketParams::COMBINE_CONNECT_AND_WRITE_DESIRED) {
 287     transport_socket_->EnableTCPFastOpenIfSupported();
 288   }
 289
 290   int rv = transport_socket_->Connect(helper_.on_io_complete());
 291   if (rv == ERR_IO_PENDING && try_ipv6_connect_with_ipv4_fallback) {
 292     fallback_timer_.Start(
 293         FROM_HERE,
 294         base::TimeDelta::FromMilliseconds(
 295             TransportConnectJobHelper::kIPv6FallbackTimerInMs),
 296         this,
 297         &TransportConnectJob::DoIPv6FallbackTransportConnect);
 298   }
 299   return rv;
 300 }
 301
 302 int TransportConnectJob::DoTransportConnectComplete(int result) {
 303   if (result == OK) {
 304     bool is_ipv4 =
 305         helper_.addresses().front().GetFamily() == ADDRESS_FAMILY_IPV4;
 306     TransportConnectJobHelper::ConnectionLatencyHistogram race_result =
 307         TransportConnectJobHelper::CONNECTION_LATENCY_UNKNOWN;
 308     if (is_ipv4) {
 309       race_result = TransportConnectJobHelper::CONNECTION_LATENCY_IPV4_NO_RACE;
 310     } else {
 311       if (AddressListOnlyContainsIPv6(helper_.addresses())) {
 312         race_result = TransportConnectJobHelper::CONNECTION_LATENCY_IPV6_SOLO;
 313       } else {
 314         race_result =
 315             TransportConnectJobHelper::CONNECTION_LATENCY_IPV6_RACEABLE;
 316       }
 317     }
 318     base::TimeDelta connect_duration = helper_.HistogramDuration(race_result);
 319     switch (interval_between_connects_) {
 320       case CONNECT_INTERVAL_LE_10MS:
 321         UMA_HISTOGRAM_CUSTOM_TIMES(
 322             "Net.TCP_Connection_Latency_Interval_LessThanOrEqual_10ms",
 323             connect_duration,
 324             base::TimeDelta::FromMilliseconds(1),
 325             base::TimeDelta::FromMinutes(10),
 326             100);
 327         break;
 328       case CONNECT_INTERVAL_LE_20MS:
 329         UMA_HISTOGRAM_CUSTOM_TIMES(
 330             "Net.TCP_Connection_Latency_Interval_LessThanOrEqual_20ms",
 331             connect_duration,
 332             base::TimeDelta::FromMilliseconds(1),
 333             base::TimeDelta::FromMinutes(10),
 334             100);
 335         break;
 336       case CONNECT_INTERVAL_GT_20MS:
 337         UMA_HISTOGRAM_CUSTOM_TIMES(
 338             "Net.TCP_Connection_Latency_Interval_GreaterThan_20ms",
 339             connect_duration,
 340             base::TimeDelta::FromMilliseconds(1),
 341             base::TimeDelta::FromMinutes(10),
 342             100);
 343         break;
 344       default:
 345         NOTREACHED();
 346         break;
 347     }
 348
 349     SetSocket(transport_socket_.Pass());
 350     fallback_timer_.Stop();
 351   } else {
 352     // Be a bit paranoid and kill off the fallback members to prevent reuse.
 353     fallback_transport_socket_.reset();
 354     fallback_addresses_.reset();
 355   }
 356
 357   return result;
 358 }
 359
 360 void TransportConnectJob::DoIPv6FallbackTransportConnect() {
 361   // The timer should only fire while we're waiting for the main connect to
 362   // succeed.
 363   if (helper_.next_state() !=
 364       TransportConnectJobHelper::STATE_TRANSPORT_CONNECT_COMPLETE) {
 365     NOTREACHED();
 366     return;
 367   }
 368
 369   DCHECK(!fallback_transport_socket_.get());
 370   DCHECK(!fallback_addresses_.get());
 371
 372   fallback_addresses_.reset(new AddressList(helper_.addresses()));
 373   MakeAddressListStartWithIPv4(fallback_addresses_.get());
 374   fallback_transport_socket_ =
 375       helper_.client_socket_factory()->CreateTransportClientSocket(
 376           *fallback_addresses_, net_log().net_log(), net_log().source());
 377   fallback_connect_start_time_ = base::TimeTicks::Now();
 378   int rv = fallback_transport_socket_->Connect(
 379       base::Bind(
 380           &TransportConnectJob::DoIPv6FallbackTransportConnectComplete,
 381           base::Unretained(this)));
 382   if (rv != ERR_IO_PENDING)
 383     DoIPv6FallbackTransportConnectComplete(rv);
 384 }
 385
 386 void TransportConnectJob::DoIPv6FallbackTransportConnectComplete(int result) {
 387   // This should only happen when we're waiting for the main connect to succeed.
 388   if (helper_.next_state() !=
 389       TransportConnectJobHelper::STATE_TRANSPORT_CONNECT_COMPLETE) {
 390     NOTREACHED();
 391     return;
 392   }
 393
 394   DCHECK_NE(ERR_IO_PENDING, result);
 395   DCHECK(fallback_transport_socket_.get());
 396   DCHECK(fallback_addresses_.get());
 397
 398   if (result == OK) {
 399     DCHECK(!fallback_connect_start_time_.is_null());
 400     connect_timing_.connect_start = fallback_connect_start_time_;
 401     helper_.HistogramDuration(
 402         TransportConnectJobHelper::CONNECTION_LATENCY_IPV4_WINS_RACE);
 403     SetSocket(fallback_transport_socket_.Pass());
 404     helper_.set_next_state(TransportConnectJobHelper::STATE_NONE);
 405     transport_socket_.reset();
 406   } else {
 407     // Be a bit paranoid and kill off the fallback members to prevent reuse.
 408     fallback_transport_socket_.reset();
 409     fallback_addresses_.reset();
 410   }
 411   NotifyDelegateOfCompletion(result);  // Deletes |this|
 412 }
 413
 414 int TransportConnectJob::ConnectInternal() {
 415   return helper_.DoConnectInternal(this);
 416 }
 417
 418 scoped_ptr<ConnectJob>
 419 TransportClientSocketPool::TransportConnectJobFactory::NewConnectJob(
 420     const std::string& group_name,
 421     const PoolBase::Request& request,
 422     ConnectJob::Delegate* delegate) const {
 423   return scoped_ptr<ConnectJob>(
 424       new TransportConnectJob(group_name,
 425                               request.priority(),
 426                               request.params(),
 427                               ConnectionTimeout(),
 428                               client_socket_factory_,
 429                               host_resolver_,
 430                               delegate,
 431                               net_log_));
 432 }
 433
 434 base::TimeDelta
 435     TransportClientSocketPool::TransportConnectJobFactory::ConnectionTimeout()
 436     const {
 437   return base::TimeDelta::FromSeconds(kTransportConnectJobTimeoutInSeconds);
 438 }
 439
 440 TransportClientSocketPool::TransportClientSocketPool(
 441     int max_sockets,
 442     int max_sockets_per_group,
 443     ClientSocketPoolHistograms* histograms,
 444     HostResolver* host_resolver,
 445     ClientSocketFactory* client_socket_factory,
 446     NetLog* net_log)
 447     : base_(NULL, max_sockets, max_sockets_per_group, histograms,
 448             ClientSocketPool::unused_idle_socket_timeout(),
 449             ClientSocketPool::used_idle_socket_timeout(),
 450             new TransportConnectJobFactory(client_socket_factory,
 451                                            host_resolver, net_log)) {
 452   base_.EnableConnectBackupJobs();
 453 }
 454
 455 TransportClientSocketPool::~TransportClientSocketPool() {}
 456
 457 int TransportClientSocketPool::RequestSocket(
 458     const std::string& group_name,
 459     const void* params,
 460     RequestPriority priority,
 461     ClientSocketHandle* handle,
 462     const CompletionCallback& callback,
 463     const BoundNetLog& net_log) {
 464   const scoped_refptr<TransportSocketParams>* casted_params =
 465       static_cast<const scoped_refptr<TransportSocketParams>*>(params);
 466
 467   NetLogTcpClientSocketPoolRequestedSocket(net_log, casted_params);
 468
 469   return base_.RequestSocket(group_name, *casted_params, priority, handle,
 470                              callback, net_log);
 471 }
 472
 473 void TransportClientSocketPool::NetLogTcpClientSocketPoolRequestedSocket(
 474     const BoundNetLog& net_log,
 475     const scoped_refptr<TransportSocketParams>* casted_params) {
 476   if (net_log.IsLogging()) {
 477     // TODO(eroman): Split out the host and port parameters.
 478     net_log.AddEvent(
 479         NetLog::TYPE_TCP_CLIENT_SOCKET_POOL_REQUESTED_SOCKET,
 480         CreateNetLogHostPortPairCallback(
 481             &casted_params->get()->destination().host_port_pair()));
 482   }
 483 }
 484
 485 void TransportClientSocketPool::RequestSockets(
 486     const std::string& group_name,
 487     const void* params,
 488     int num_sockets,
 489     const BoundNetLog& net_log) {
 490   const scoped_refptr<TransportSocketParams>* casted_params =
 491       static_cast<const scoped_refptr<TransportSocketParams>*>(params);
 492
 493   if (net_log.IsLogging()) {
 494     // TODO(eroman): Split out the host and port parameters.
 495     net_log.AddEvent(
 496         NetLog::TYPE_TCP_CLIENT_SOCKET_POOL_REQUESTED_SOCKETS,
 497         CreateNetLogHostPortPairCallback(
 498             &casted_params->get()->destination().host_port_pair()));
 499   }
 500
 501   base_.RequestSockets(group_name, *casted_params, num_sockets, net_log);
 502 }
 503
 504 void TransportClientSocketPool::CancelRequest(
 505     const std::string& group_name,
 506     ClientSocketHandle* handle) {
 507   base_.CancelRequest(group_name, handle);
 508 }
 509
 510 void TransportClientSocketPool::ReleaseSocket(
 511     const std::string& group_name,
 512     scoped_ptr<StreamSocket> socket,
 513     int id) {
 514   base_.ReleaseSocket(group_name, socket.Pass(), id);
 515 }
 516
 517 void TransportClientSocketPool::FlushWithError(int error) {
 518   base_.FlushWithError(error);
 519 }
 520
 521 void TransportClientSocketPool::CloseIdleSockets() {
 522   base_.CloseIdleSockets();
 523 }
 524
 525 int TransportClientSocketPool::IdleSocketCount() const {
 526   return base_.idle_socket_count();
 527 }
 528
 529 int TransportClientSocketPool::IdleSocketCountInGroup(
 530     const std::string& group_name) const {
 531   return base_.IdleSocketCountInGroup(group_name);
 532 }
 533
 534 LoadState TransportClientSocketPool::GetLoadState(
 535     const std::string& group_name, const ClientSocketHandle* handle) const {
 536   return base_.GetLoadState(group_name, handle);
 537 }
 538
 539 base::DictionaryValue* TransportClientSocketPool::GetInfoAsValue(
 540     const std::string& name,
 541     const std::string& type,
 542     bool include_nested_pools) const {
 543   return base_.GetInfoAsValue(name, type);
 544 }
 545
 546 base::TimeDelta TransportClientSocketPool::ConnectionTimeout() const {
 547   return base_.ConnectionTimeout();
 548 }
 549
 550 ClientSocketPoolHistograms* TransportClientSocketPool::histograms() const {
 551   return base_.histograms();
 552 }
 553
 554 bool TransportClientSocketPool::IsStalled() const {
 555   return base_.IsStalled();
 556 }
 557
 558 void TransportClientSocketPool::AddHigherLayeredPool(
 559     HigherLayeredPool* higher_pool) {
 560   base_.AddHigherLayeredPool(higher_pool);
 561 }
 562
 563 void TransportClientSocketPool::RemoveHigherLayeredPool(
 564     HigherLayeredPool* higher_pool) {
 565   base_.RemoveHigherLayeredPool(higher_pool);
 566 }
 567
 568 }  // namespace net