net/proxy/dhcp_proxy_script_fetcher_win.cc - chromium/src - Git at Google

 // 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/proxy/dhcp_proxy_script_fetcher_win.h"

 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "net/base/net_errors.h"
 #include "net/proxy/dhcp_proxy_script_adapter_fetcher_win.h"

 #include <winsock2.h>
 #include <iphlpapi.h>
 #pragma comment(lib, "iphlpapi.lib")

 namespace {

 // How many threads to use at maximum to do DHCP lookups. This is
 // chosen based on the following UMA data:
 // - When OnWaitTimer fires, ~99.8% of users have 6 or fewer network
 //   adapters enabled for DHCP in total.
 // - At the same measurement point, ~99.7% of users have 3 or fewer pending
 //   DHCP adapter lookups.
 // - There is however a very long and thin tail of users who have
 //   systems reporting up to 100+ adapters (this must be some very weird
 //   OS bug (?), probably the cause of http://crbug.com/240034).
 //
 // The maximum number of threads is chosen such that even systems that
 // report a huge number of network adapters should not run out of
 // memory from this number of threads, while giving a good chance of
 // getting back results for any responsive adapters.
 //
 // The ~99.8% of systems that have 6 or fewer network adapters will
 // not grow the thread pool to its maximum size (rather, they will
 // grow it to 6 or fewer threads) so setting the limit lower would not
 // improve performance or memory usage on those systems.
 const int kMaxDhcpLookupThreads = 12;

 // How long to wait at maximum after we get results (a PAC file or
 // knowledge that no PAC file is configured) from whichever network
 // adapter finishes first.
 const int kMaxWaitAfterFirstResultMs = 400;

 const int kGetAdaptersAddressesErrors[] = {
   ERROR_ADDRESS_NOT_ASSOCIATED,
   ERROR_BUFFER_OVERFLOW,
   ERROR_INVALID_PARAMETER,
   ERROR_NOT_ENOUGH_MEMORY,
   ERROR_NO_DATA,
 };

 }  // namespace

 namespace net {

 DhcpProxyScriptFetcherWin::DhcpProxyScriptFetcherWin(
     URLRequestContext* url_request_context)
     : state_(STATE_START),
       num_pending_fetchers_(0),
       destination_string_(NULL),
       url_request_context_(url_request_context) {
   DCHECK(url_request_context_);

   worker_pool_ = new base::SequencedWorkerPool(kMaxDhcpLookupThreads,
                                                "PacDhcpLookup");
 }

 DhcpProxyScriptFetcherWin::~DhcpProxyScriptFetcherWin() {
   // Count as user-initiated if we are not yet in STATE_DONE.
   Cancel();

   worker_pool_->Shutdown();
 }

 int DhcpProxyScriptFetcherWin::Fetch(base::string16* utf16_text,
                                      const CompletionCallback& callback) {
   DCHECK(CalledOnValidThread());
   if (state_ != STATE_START && state_ != STATE_DONE) {
     NOTREACHED();
     return ERR_UNEXPECTED;
   }

   state_ = STATE_WAIT_ADAPTERS;
   callback_ = callback;
   destination_string_ = utf16_text;

   last_query_ = ImplCreateAdapterQuery();
   GetTaskRunner()->PostTaskAndReply(
       FROM_HERE,
       base::Bind(
           &DhcpProxyScriptFetcherWin::AdapterQuery::GetCandidateAdapterNames,
           last_query_.get()),
       base::Bind(
           &DhcpProxyScriptFetcherWin::OnGetCandidateAdapterNamesDone,
           AsWeakPtr(),
           last_query_));

   return ERR_IO_PENDING;
 }

 void DhcpProxyScriptFetcherWin::Cancel() {
   DCHECK(CalledOnValidThread());

   CancelImpl();
 }

 void DhcpProxyScriptFetcherWin::CancelImpl() {
   DCHECK(CalledOnValidThread());

   if (state_ != STATE_DONE) {
     callback_.Reset();
     wait_timer_.Stop();
     state_ = STATE_DONE;

     for (FetcherVector::iterator it = fetchers_.begin();
          it != fetchers_.end();
          ++it) {
       (*it)->Cancel();
     }

     fetchers_.clear();
   }
 }

 void DhcpProxyScriptFetcherWin::OnGetCandidateAdapterNamesDone(
     scoped_refptr<AdapterQuery> query) {
   DCHECK(CalledOnValidThread());

   // This can happen if this object is reused for multiple queries,
   // and a previous query was cancelled before it completed.
   if (query.get() != last_query_.get())
     return;
   last_query_ = NULL;

   // Enable unit tests to wait for this to happen; in production this function
   // call is a no-op.
   ImplOnGetCandidateAdapterNamesDone();

   // We may have been cancelled.
   if (state_ != STATE_WAIT_ADAPTERS)
     return;

   state_ = STATE_NO_RESULTS;

   const std::set<std::string>& adapter_names = query->adapter_names();

   if (adapter_names.empty()) {
     TransitionToDone();
     return;
   }

   for (std::set<std::string>::const_iterator it = adapter_names.begin();
        it != adapter_names.end();
        ++it) {
     DhcpProxyScriptAdapterFetcher* fetcher(ImplCreateAdapterFetcher());
     fetcher->Fetch(
         *it, base::Bind(&DhcpProxyScriptFetcherWin::OnFetcherDone,
                         base::Unretained(this)));
     fetchers_.push_back(fetcher);
   }
   num_pending_fetchers_ = fetchers_.size();
 }

 std::string DhcpProxyScriptFetcherWin::GetFetcherName() const {
   DCHECK(CalledOnValidThread());
   return "win";
 }

 const GURL& DhcpProxyScriptFetcherWin::GetPacURL() const {
   DCHECK(CalledOnValidThread());
   DCHECK_EQ(state_, STATE_DONE);

   return pac_url_;
 }

 void DhcpProxyScriptFetcherWin::OnFetcherDone(int result) {
   DCHECK(state_ == STATE_NO_RESULTS || state_ == STATE_SOME_RESULTS);

   if (--num_pending_fetchers_ == 0) {
     TransitionToDone();
     return;
   }

   // If the only pending adapters are those less preferred than one
   // with a valid PAC script, we do not need to wait any longer.
   for (FetcherVector::iterator it = fetchers_.begin();
        it != fetchers_.end();
        ++it) {
     bool did_finish = (*it)->DidFinish();
     int result = (*it)->GetResult();
     if (did_finish && result == OK) {
       TransitionToDone();
       return;
     }
     if (!did_finish || result != ERR_PAC_NOT_IN_DHCP) {
       break;
     }
   }

   // Once we have a single result, we set a maximum on how long to wait
   // for the rest of the results.
   if (state_ == STATE_NO_RESULTS) {
     state_ = STATE_SOME_RESULTS;
     wait_timer_.Start(FROM_HERE,
         ImplGetMaxWait(), this, &DhcpProxyScriptFetcherWin::OnWaitTimer);
   }
 }

 void DhcpProxyScriptFetcherWin::OnWaitTimer() {
   DCHECK_EQ(state_, STATE_SOME_RESULTS);

   TransitionToDone();
 }

 void DhcpProxyScriptFetcherWin::TransitionToDone() {
   DCHECK(state_ == STATE_NO_RESULTS || state_ == STATE_SOME_RESULTS);

   int result = ERR_PAC_NOT_IN_DHCP;  // Default if no fetchers.
   if (!fetchers_.empty()) {
     // Scan twice for the result; once through the whole list for success,
     // then if no success, return result for most preferred network adapter,
     // preferring "real" network errors to the ERR_PAC_NOT_IN_DHCP error.
     // Default to ERR_ABORTED if no fetcher completed.
     result = ERR_ABORTED;
     for (FetcherVector::iterator it = fetchers_.begin();
          it != fetchers_.end();
          ++it) {
       if ((*it)->DidFinish() && (*it)->GetResult() == OK) {
         result = OK;
         *destination_string_ = (*it)->GetPacScript();
         pac_url_ = (*it)->GetPacURL();
         break;
       }
     }
     if (result != OK) {
       destination_string_->clear();
       for (FetcherVector::iterator it = fetchers_.begin();
            it != fetchers_.end();
            ++it) {
         if ((*it)->DidFinish()) {
           result = (*it)->GetResult();
           if (result != ERR_PAC_NOT_IN_DHCP) {
             break;
           }
         }
       }
     }
   }

   CompletionCallback callback = callback_;
   CancelImpl();
   DCHECK_EQ(state_, STATE_DONE);
   DCHECK(fetchers_.empty());
   DCHECK(callback_.is_null());  // Invariant of data.

   // We may be deleted re-entrantly within this outcall.
   callback.Run(result);
 }

 int DhcpProxyScriptFetcherWin::num_pending_fetchers() const {
   return num_pending_fetchers_;
 }

 URLRequestContext* DhcpProxyScriptFetcherWin::url_request_context() const {
   return url_request_context_;
 }

 scoped_refptr<base::TaskRunner> DhcpProxyScriptFetcherWin::GetTaskRunner() {
   return worker_pool_->GetTaskRunnerWithShutdownBehavior(
       base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
 }

 DhcpProxyScriptAdapterFetcher*
     DhcpProxyScriptFetcherWin::ImplCreateAdapterFetcher() {
   return new DhcpProxyScriptAdapterFetcher(url_request_context_,
                                            GetTaskRunner());
 }

 DhcpProxyScriptFetcherWin::AdapterQuery*
     DhcpProxyScriptFetcherWin::ImplCreateAdapterQuery() {
   return new AdapterQuery();
 }

 base::TimeDelta DhcpProxyScriptFetcherWin::ImplGetMaxWait() {
   return base::TimeDelta::FromMilliseconds(kMaxWaitAfterFirstResultMs);
 }

 bool DhcpProxyScriptFetcherWin::GetCandidateAdapterNames(
     std::set<std::string>* adapter_names) {
   DCHECK(adapter_names);
   adapter_names->clear();

   // The GetAdaptersAddresses MSDN page recommends using a size of 15000 to
   // avoid reallocation.
   ULONG adapters_size = 15000;
   scoped_ptr<IP_ADAPTER_ADDRESSES, base::FreeDeleter> adapters;
   ULONG error = ERROR_SUCCESS;
   int num_tries = 0;

   do {
     adapters.reset(static_cast<IP_ADAPTER_ADDRESSES*>(malloc(adapters_size)));
     // Return only unicast addresses, and skip information we do not need.
     error = GetAdaptersAddresses(AF_UNSPEC,
                                  GAA_FLAG_SKIP_ANYCAST |
                                  GAA_FLAG_SKIP_MULTICAST |
                                  GAA_FLAG_SKIP_DNS_SERVER |
                                  GAA_FLAG_SKIP_FRIENDLY_NAME,
                                  NULL,
                                  adapters.get(),
                                  &adapters_size);
     ++num_tries;
   } while (error == ERROR_BUFFER_OVERFLOW && num_tries <= 3);

   if (error == ERROR_NO_DATA) {
     // There are no adapters that we care about.
     return true;
   }

   if (error != ERROR_SUCCESS) {
     LOG(WARNING) << "Unexpected error retrieving WPAD configuration from DHCP.";
     return false;
   }

   IP_ADAPTER_ADDRESSES* adapter = NULL;
   for (adapter = adapters.get(); adapter; adapter = adapter->Next) {
     if (adapter->IfType == IF_TYPE_SOFTWARE_LOOPBACK)
       continue;
     if ((adapter->Flags & IP_ADAPTER_DHCP_ENABLED) == 0)
       continue;

     DCHECK(adapter->AdapterName);
     adapter_names->insert(adapter->AdapterName);
   }

   return true;
 }

 DhcpProxyScriptFetcherWin::AdapterQuery::AdapterQuery() {
 }

 DhcpProxyScriptFetcherWin::AdapterQuery::~AdapterQuery() {
 }

 void DhcpProxyScriptFetcherWin::AdapterQuery::GetCandidateAdapterNames() {
   ImplGetCandidateAdapterNames(&adapter_names_);
 }

 const std::set<std::string>&
     DhcpProxyScriptFetcherWin::AdapterQuery::adapter_names() const {
   return adapter_names_;
 }

 bool DhcpProxyScriptFetcherWin::AdapterQuery::ImplGetCandidateAdapterNames(
     std::set<std::string>* adapter_names) {
   return DhcpProxyScriptFetcherWin::GetCandidateAdapterNames(adapter_names);
 }

 }  // namespace net
	// 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/proxy/dhcp_proxy_script_fetcher_win.h"

	#include "base/bind.h"
	#include "base/bind_helpers.h"
	#include "base/threading/sequenced_worker_pool.h"
	#include "net/base/net_errors.h"
	#include "net/proxy/dhcp_proxy_script_adapter_fetcher_win.h"

	#include <winsock2.h>
	#include <iphlpapi.h>
	#pragma comment(lib, "iphlpapi.lib")

	namespace {

	// How many threads to use at maximum to do DHCP lookups. This is
	// chosen based on the following UMA data:
	// - When OnWaitTimer fires, ~99.8% of users have 6 or fewer network
	// adapters enabled for DHCP in total.
	// - At the same measurement point, ~99.7% of users have 3 or fewer pending
	// DHCP adapter lookups.
	// - There is however a very long and thin tail of users who have
	// systems reporting up to 100+ adapters (this must be some very weird
	// OS bug (?), probably the cause of http://crbug.com/240034).
	//
	// The maximum number of threads is chosen such that even systems that
	// report a huge number of network adapters should not run out of
	// memory from this number of threads, while giving a good chance of
	// getting back results for any responsive adapters.
	//
	// The ~99.8% of systems that have 6 or fewer network adapters will
	// not grow the thread pool to its maximum size (rather, they will
	// grow it to 6 or fewer threads) so setting the limit lower would not
	// improve performance or memory usage on those systems.
	const int kMaxDhcpLookupThreads = 12;

	// How long to wait at maximum after we get results (a PAC file or
	// knowledge that no PAC file is configured) from whichever network
	// adapter finishes first.
	const int kMaxWaitAfterFirstResultMs = 400;

	const int kGetAdaptersAddressesErrors[] = {
	ERROR_ADDRESS_NOT_ASSOCIATED,
	ERROR_BUFFER_OVERFLOW,
	ERROR_INVALID_PARAMETER,
	ERROR_NOT_ENOUGH_MEMORY,
	ERROR_NO_DATA,
	};

	} // namespace

	namespace net {

	DhcpProxyScriptFetcherWin::DhcpProxyScriptFetcherWin(
	URLRequestContext* url_request_context)
	: state_(STATE_START),
	num_pending_fetchers_(0),
	destination_string_(NULL),
	url_request_context_(url_request_context) {
	DCHECK(url_request_context_);

	worker_pool_ = new base::SequencedWorkerPool(kMaxDhcpLookupThreads,
	"PacDhcpLookup");
	}

	DhcpProxyScriptFetcherWin::~DhcpProxyScriptFetcherWin() {
	// Count as user-initiated if we are not yet in STATE_DONE.
	Cancel();

	worker_pool_->Shutdown();
	}

	int DhcpProxyScriptFetcherWin::Fetch(base::string16* utf16_text,
	const CompletionCallback& callback) {
	DCHECK(CalledOnValidThread());
	if (state_ != STATE_START && state_ != STATE_DONE) {
	NOTREACHED();
	return ERR_UNEXPECTED;
	}

	state_ = STATE_WAIT_ADAPTERS;
	callback_ = callback;
	destination_string_ = utf16_text;

	last_query_ = ImplCreateAdapterQuery();
	GetTaskRunner()->PostTaskAndReply(
	FROM_HERE,
	base::Bind(
	&DhcpProxyScriptFetcherWin::AdapterQuery::GetCandidateAdapterNames,
	last_query_.get()),
	base::Bind(
	&DhcpProxyScriptFetcherWin::OnGetCandidateAdapterNamesDone,
	AsWeakPtr(),
	last_query_));

	return ERR_IO_PENDING;
	}

	void DhcpProxyScriptFetcherWin::Cancel() {
	DCHECK(CalledOnValidThread());

	CancelImpl();
	}

	void DhcpProxyScriptFetcherWin::CancelImpl() {
	DCHECK(CalledOnValidThread());

	if (state_ != STATE_DONE) {
	callback_.Reset();
	wait_timer_.Stop();
	state_ = STATE_DONE;

	for (FetcherVector::iterator it = fetchers_.begin();
	it != fetchers_.end();
	++it) {
	(*it)->Cancel();
	}

	fetchers_.clear();
	}
	}

	void DhcpProxyScriptFetcherWin::OnGetCandidateAdapterNamesDone(
	scoped_refptr<AdapterQuery> query) {
	DCHECK(CalledOnValidThread());

	// This can happen if this object is reused for multiple queries,
	// and a previous query was cancelled before it completed.
	if (query.get() != last_query_.get())
	return;
	last_query_ = NULL;

	// Enable unit tests to wait for this to happen; in production this function
	// call is a no-op.
	ImplOnGetCandidateAdapterNamesDone();

	// We may have been cancelled.
	if (state_ != STATE_WAIT_ADAPTERS)
	return;

	state_ = STATE_NO_RESULTS;

	const std::set<std::string>& adapter_names = query->adapter_names();

	if (adapter_names.empty()) {
	TransitionToDone();
	return;
	}

	for (std::set<std::string>::const_iterator it = adapter_names.begin();
	it != adapter_names.end();
	++it) {
	DhcpProxyScriptAdapterFetcher* fetcher(ImplCreateAdapterFetcher());
	fetcher->Fetch(
	*it, base::Bind(&DhcpProxyScriptFetcherWin::OnFetcherDone,
	base::Unretained(this)));
	fetchers_.push_back(fetcher);
	}
	num_pending_fetchers_ = fetchers_.size();
	}

	std::string DhcpProxyScriptFetcherWin::GetFetcherName() const {
	DCHECK(CalledOnValidThread());
	return "win";
	}

	const GURL& DhcpProxyScriptFetcherWin::GetPacURL() const {
	DCHECK(CalledOnValidThread());
	DCHECK_EQ(state_, STATE_DONE);

	return pac_url_;
	}

	void DhcpProxyScriptFetcherWin::OnFetcherDone(int result) {
	DCHECK(state_ == STATE_NO_RESULTS \|\| state_ == STATE_SOME_RESULTS);

	if (--num_pending_fetchers_ == 0) {
	TransitionToDone();
	return;
	}

	// If the only pending adapters are those less preferred than one
	// with a valid PAC script, we do not need to wait any longer.
	for (FetcherVector::iterator it = fetchers_.begin();
	it != fetchers_.end();
	++it) {
	bool did_finish = (*it)->DidFinish();
	int result = (*it)->GetResult();
	if (did_finish && result == OK) {
	TransitionToDone();
	return;
	}
	if (!did_finish \|\| result != ERR_PAC_NOT_IN_DHCP) {
	break;
	}
	}

	// Once we have a single result, we set a maximum on how long to wait
	// for the rest of the results.
	if (state_ == STATE_NO_RESULTS) {
	state_ = STATE_SOME_RESULTS;
	wait_timer_.Start(FROM_HERE,
	ImplGetMaxWait(), this, &DhcpProxyScriptFetcherWin::OnWaitTimer);
	}
	}

	void DhcpProxyScriptFetcherWin::OnWaitTimer() {
	DCHECK_EQ(state_, STATE_SOME_RESULTS);

	TransitionToDone();
	}

	void DhcpProxyScriptFetcherWin::TransitionToDone() {
	DCHECK(state_ == STATE_NO_RESULTS \|\| state_ == STATE_SOME_RESULTS);

	int result = ERR_PAC_NOT_IN_DHCP; // Default if no fetchers.
	if (!fetchers_.empty()) {
	// Scan twice for the result; once through the whole list for success,
	// then if no success, return result for most preferred network adapter,
	// preferring "real" network errors to the ERR_PAC_NOT_IN_DHCP error.
	// Default to ERR_ABORTED if no fetcher completed.
	result = ERR_ABORTED;
	for (FetcherVector::iterator it = fetchers_.begin();
	it != fetchers_.end();
	++it) {
	if ((it)->DidFinish() && (it)->GetResult() == OK) {
	result = OK;
	destination_string_ = (it)->GetPacScript();
	pac_url_ = (*it)->GetPacURL();
	break;
	}
	}
	if (result != OK) {
	destination_string_->clear();
	for (FetcherVector::iterator it = fetchers_.begin();
	it != fetchers_.end();
	++it) {
	if ((*it)->DidFinish()) {
	result = (*it)->GetResult();
	if (result != ERR_PAC_NOT_IN_DHCP) {
	break;
	}
	}
	}
	}
	}

	CompletionCallback callback = callback_;
	CancelImpl();
	DCHECK_EQ(state_, STATE_DONE);
	DCHECK(fetchers_.empty());
	DCHECK(callback_.is_null()); // Invariant of data.

	// We may be deleted re-entrantly within this outcall.
	callback.Run(result);
	}

	int DhcpProxyScriptFetcherWin::num_pending_fetchers() const {
	return num_pending_fetchers_;
	}

	URLRequestContext* DhcpProxyScriptFetcherWin::url_request_context() const {
	return url_request_context_;
	}

	scoped_refptr<base::TaskRunner> DhcpProxyScriptFetcherWin::GetTaskRunner() {
	return worker_pool_->GetTaskRunnerWithShutdownBehavior(
	base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
	}

	DhcpProxyScriptAdapterFetcher*
	DhcpProxyScriptFetcherWin::ImplCreateAdapterFetcher() {
	return new DhcpProxyScriptAdapterFetcher(url_request_context_,
	GetTaskRunner());
	}

	DhcpProxyScriptFetcherWin::AdapterQuery*
	DhcpProxyScriptFetcherWin::ImplCreateAdapterQuery() {
	return new AdapterQuery();
	}

	base::TimeDelta DhcpProxyScriptFetcherWin::ImplGetMaxWait() {
	return base::TimeDelta::FromMilliseconds(kMaxWaitAfterFirstResultMs);
	}

	bool DhcpProxyScriptFetcherWin::GetCandidateAdapterNames(
	std::set<std::string>* adapter_names) {
	DCHECK(adapter_names);
	adapter_names->clear();

	// The GetAdaptersAddresses MSDN page recommends using a size of 15000 to
	// avoid reallocation.
	ULONG adapters_size = 15000;
	scoped_ptr<IP_ADAPTER_ADDRESSES, base::FreeDeleter> adapters;
	ULONG error = ERROR_SUCCESS;
	int num_tries = 0;

	do {
	adapters.reset(static_cast<IP_ADAPTER_ADDRESSES*>(malloc(adapters_size)));
	// Return only unicast addresses, and skip information we do not need.
	error = GetAdaptersAddresses(AF_UNSPEC,
	GAA_FLAG_SKIP_ANYCAST \|
	GAA_FLAG_SKIP_MULTICAST \|
	GAA_FLAG_SKIP_DNS_SERVER \|
	GAA_FLAG_SKIP_FRIENDLY_NAME,
	NULL,
	adapters.get(),
	&adapters_size);
	++num_tries;
	} while (error == ERROR_BUFFER_OVERFLOW && num_tries <= 3);

	if (error == ERROR_NO_DATA) {
	// There are no adapters that we care about.
	return true;
	}

	if (error != ERROR_SUCCESS) {
	LOG(WARNING) << "Unexpected error retrieving WPAD configuration from DHCP.";
	return false;
	}

	IP_ADAPTER_ADDRESSES* adapter = NULL;
	for (adapter = adapters.get(); adapter; adapter = adapter->Next) {
	if (adapter->IfType == IF_TYPE_SOFTWARE_LOOPBACK)
	continue;
	if ((adapter->Flags & IP_ADAPTER_DHCP_ENABLED) == 0)
	continue;

	DCHECK(adapter->AdapterName);
	adapter_names->insert(adapter->AdapterName);
	}

	return true;
	}

	DhcpProxyScriptFetcherWin::AdapterQuery::AdapterQuery() {
	}

	DhcpProxyScriptFetcherWin::AdapterQuery::~AdapterQuery() {
	}

	void DhcpProxyScriptFetcherWin::AdapterQuery::GetCandidateAdapterNames() {
	ImplGetCandidateAdapterNames(&adapter_names_);
	}

	const std::set<std::string>&
	DhcpProxyScriptFetcherWin::AdapterQuery::adapter_names() const {
	return adapter_names_;
	}

	bool DhcpProxyScriptFetcherWin::AdapterQuery::ImplGetCandidateAdapterNames(
	std::set<std::string>* adapter_names) {
	return DhcpProxyScriptFetcherWin::GetCandidateAdapterNames(adapter_names);
	}

	} // namespace net