blob: 939f7af1422a413fa5fd8a140b308d04e0843af6 [file] [log] [blame]
// 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/proxy_script_decider.h"
#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/compiler_specific.h"
#include "base/format_macros.h"
#include "base/logging.h"
#include "base/metrics/histogram.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/values.h"
#include "net/base/net_errors.h"
#include "net/proxy/dhcp_proxy_script_fetcher.h"
#include "net/proxy/dhcp_proxy_script_fetcher_factory.h"
#include "net/proxy/proxy_script_fetcher.h"
#include "net/url_request/url_request_context.h"
namespace net {
namespace {
bool LooksLikePacScript(const base::string16& script) {
// Note: this is only an approximation! It may not always work correctly,
// however it is very likely that legitimate scripts have this exact string,
// since they must minimally define a function of this name. Conversely, a
// file not containing the string is not likely to be a PAC script.
//
// An exact test would have to load the script in a javascript evaluator.
return script.find(base::ASCIIToUTF16("FindProxyForURL")) !=
base::string16::npos;
}
}
// This is the hard-coded location used by the DNS portion of web proxy
// auto-discovery.
//
// Note that we not use DNS devolution to find the WPAD host, since that could
// be dangerous should our top level domain registry become out of date.
//
// Instead we directly resolve "wpad", and let the operating system apply the
// DNS suffix search paths. This is the same approach taken by Firefox, and
// compatibility hasn't been an issue.
//
// For more details, also check out this comment:
// http://code.google.com/p/chromium/issues/detail?id=18575#c20
namespace {
const char kWpadUrl[] = "http://wpad/wpad.dat";
const int kQuickCheckDelayMs = 1000;
};
base::Value* ProxyScriptDecider::PacSource::NetLogCallback(
const GURL* effective_pac_url,
NetLog::LogLevel /* log_level */) const {
base::DictionaryValue* dict = new base::DictionaryValue();
std::string source;
switch (type) {
case PacSource::WPAD_DHCP:
source = "WPAD DHCP";
break;
case PacSource::WPAD_DNS:
source = "WPAD DNS: ";
source += effective_pac_url->possibly_invalid_spec();
break;
case PacSource::CUSTOM:
source = "Custom PAC URL: ";
source += effective_pac_url->possibly_invalid_spec();
break;
}
dict->SetString("source", source);
return dict;
}
ProxyScriptDecider::ProxyScriptDecider(
ProxyScriptFetcher* proxy_script_fetcher,
DhcpProxyScriptFetcher* dhcp_proxy_script_fetcher,
NetLog* net_log)
: resolver_(NULL),
proxy_script_fetcher_(proxy_script_fetcher),
dhcp_proxy_script_fetcher_(dhcp_proxy_script_fetcher),
current_pac_source_index_(0u),
pac_mandatory_(false),
next_state_(STATE_NONE),
net_log_(BoundNetLog::Make(
net_log, NetLog::SOURCE_PROXY_SCRIPT_DECIDER)),
fetch_pac_bytes_(false),
quick_check_enabled_(true) {
if (proxy_script_fetcher &&
proxy_script_fetcher->GetRequestContext() &&
proxy_script_fetcher->GetRequestContext()->host_resolver()) {
host_resolver_.reset(new SingleRequestHostResolver(
proxy_script_fetcher->GetRequestContext()->host_resolver()));
}
}
ProxyScriptDecider::~ProxyScriptDecider() {
if (next_state_ != STATE_NONE)
Cancel();
}
int ProxyScriptDecider::Start(
const ProxyConfig& config, const base::TimeDelta wait_delay,
bool fetch_pac_bytes, const CompletionCallback& callback) {
DCHECK_EQ(STATE_NONE, next_state_);
DCHECK(!callback.is_null());
DCHECK(config.HasAutomaticSettings());
net_log_.BeginEvent(NetLog::TYPE_PROXY_SCRIPT_DECIDER);
fetch_pac_bytes_ = fetch_pac_bytes;
// Save the |wait_delay| as a non-negative value.
wait_delay_ = wait_delay;
if (wait_delay_ < base::TimeDelta())
wait_delay_ = base::TimeDelta();
pac_mandatory_ = config.pac_mandatory();
have_custom_pac_url_ = config.has_pac_url();
pac_sources_ = BuildPacSourcesFallbackList(config);
DCHECK(!pac_sources_.empty());
next_state_ = STATE_WAIT;
int rv = DoLoop(OK);
if (rv == ERR_IO_PENDING)
callback_ = callback;
else
DidComplete();
return rv;
}
const ProxyConfig& ProxyScriptDecider::effective_config() const {
DCHECK_EQ(STATE_NONE, next_state_);
return effective_config_;
}
// TODO(eroman): Return a const-pointer.
ProxyResolverScriptData* ProxyScriptDecider::script_data() const {
DCHECK_EQ(STATE_NONE, next_state_);
return script_data_.get();
}
// Initialize the fallback rules.
// (1) WPAD (DHCP).
// (2) WPAD (DNS).
// (3) Custom PAC URL.
ProxyScriptDecider::PacSourceList ProxyScriptDecider::
BuildPacSourcesFallbackList(
const ProxyConfig& config) const {
PacSourceList pac_sources;
if (config.auto_detect()) {
pac_sources.push_back(PacSource(PacSource::WPAD_DHCP, GURL(kWpadUrl)));
pac_sources.push_back(PacSource(PacSource::WPAD_DNS, GURL(kWpadUrl)));
}
if (config.has_pac_url())
pac_sources.push_back(PacSource(PacSource::CUSTOM, config.pac_url()));
return pac_sources;
}
void ProxyScriptDecider::OnIOCompletion(int result) {
DCHECK_NE(STATE_NONE, next_state_);
int rv = DoLoop(result);
if (rv != ERR_IO_PENDING) {
DidComplete();
DoCallback(rv);
}
}
int ProxyScriptDecider::DoLoop(int result) {
DCHECK_NE(next_state_, STATE_NONE);
int rv = result;
do {
State state = next_state_;
next_state_ = STATE_NONE;
switch (state) {
case STATE_WAIT:
DCHECK_EQ(OK, rv);
rv = DoWait();
break;
case STATE_WAIT_COMPLETE:
rv = DoWaitComplete(rv);
break;
case STATE_QUICK_CHECK:
DCHECK_EQ(OK, rv);
rv = DoQuickCheck();
break;
case STATE_QUICK_CHECK_COMPLETE:
rv = DoQuickCheckComplete(rv);
break;
case STATE_FETCH_PAC_SCRIPT:
DCHECK_EQ(OK, rv);
rv = DoFetchPacScript();
break;
case STATE_FETCH_PAC_SCRIPT_COMPLETE:
rv = DoFetchPacScriptComplete(rv);
break;
case STATE_VERIFY_PAC_SCRIPT:
DCHECK_EQ(OK, rv);
rv = DoVerifyPacScript();
break;
case STATE_VERIFY_PAC_SCRIPT_COMPLETE:
rv = DoVerifyPacScriptComplete(rv);
break;
default:
NOTREACHED() << "bad state";
rv = ERR_UNEXPECTED;
break;
}
} while (rv != ERR_IO_PENDING && next_state_ != STATE_NONE);
return rv;
}
void ProxyScriptDecider::DoCallback(int result) {
DCHECK_NE(ERR_IO_PENDING, result);
DCHECK(!callback_.is_null());
callback_.Run(result);
}
int ProxyScriptDecider::DoWait() {
next_state_ = STATE_WAIT_COMPLETE;
// If no waiting is required, continue on to the next state.
if (wait_delay_.ToInternalValue() == 0)
return OK;
// Otherwise wait the specified amount of time.
wait_timer_.Start(FROM_HERE, wait_delay_, this,
&ProxyScriptDecider::OnWaitTimerFired);
net_log_.BeginEvent(NetLog::TYPE_PROXY_SCRIPT_DECIDER_WAIT);
return ERR_IO_PENDING;
}
int ProxyScriptDecider::DoWaitComplete(int result) {
DCHECK_EQ(OK, result);
if (wait_delay_.ToInternalValue() != 0) {
net_log_.EndEventWithNetErrorCode(NetLog::TYPE_PROXY_SCRIPT_DECIDER_WAIT,
result);
}
if (quick_check_enabled_ && current_pac_source().type == PacSource::WPAD_DNS)
next_state_ = STATE_QUICK_CHECK;
else
next_state_ = GetStartState();
return OK;
}
int ProxyScriptDecider::DoQuickCheck() {
DCHECK(quick_check_enabled_);
if (host_resolver_.get() == NULL) {
// If we have no resolver, skip QuickCheck altogether.
next_state_ = GetStartState();
return OK;
}
quick_check_start_time_ = base::Time::Now();
std::string host = current_pac_source().url.host();
HostResolver::RequestInfo reqinfo(HostPortPair(host, 80));
reqinfo.set_host_resolver_flags(HOST_RESOLVER_SYSTEM_ONLY);
CompletionCallback callback = base::Bind(
&ProxyScriptDecider::OnIOCompletion,
base::Unretained(this));
next_state_ = STATE_QUICK_CHECK_COMPLETE;
quick_check_timer_.Start(FROM_HERE,
base::TimeDelta::FromMilliseconds(
kQuickCheckDelayMs),
base::Bind(callback, ERR_NAME_NOT_RESOLVED));
// We use HIGHEST here because proxy decision blocks doing any other requests.
return host_resolver_->Resolve(reqinfo, HIGHEST, &wpad_addresses_,
callback, net_log_);
}
int ProxyScriptDecider::DoQuickCheckComplete(int result) {
DCHECK(quick_check_enabled_);
base::TimeDelta delta = base::Time::Now() - quick_check_start_time_;
if (result == OK)
UMA_HISTOGRAM_TIMES("Net.WpadQuickCheckSuccess", delta);
else
UMA_HISTOGRAM_TIMES("Net.WpadQuickCheckFailure", delta);
host_resolver_->Cancel();
quick_check_timer_.Stop();
if (result != OK)
return TryToFallbackPacSource(result);
next_state_ = GetStartState();
return result;
}
int ProxyScriptDecider::DoFetchPacScript() {
DCHECK(fetch_pac_bytes_);
next_state_ = STATE_FETCH_PAC_SCRIPT_COMPLETE;
const PacSource& pac_source = current_pac_source();
GURL effective_pac_url;
DetermineURL(pac_source, &effective_pac_url);
net_log_.BeginEvent(NetLog::TYPE_PROXY_SCRIPT_DECIDER_FETCH_PAC_SCRIPT,
base::Bind(&PacSource::NetLogCallback,
base::Unretained(&pac_source),
&effective_pac_url));
if (pac_source.type == PacSource::WPAD_DHCP) {
if (!dhcp_proxy_script_fetcher_) {
net_log_.AddEvent(NetLog::TYPE_PROXY_SCRIPT_DECIDER_HAS_NO_FETCHER);
return ERR_UNEXPECTED;
}
return dhcp_proxy_script_fetcher_->Fetch(
&pac_script_, base::Bind(&ProxyScriptDecider::OnIOCompletion,
base::Unretained(this)));
}
if (!proxy_script_fetcher_) {
net_log_.AddEvent(NetLog::TYPE_PROXY_SCRIPT_DECIDER_HAS_NO_FETCHER);
return ERR_UNEXPECTED;
}
return proxy_script_fetcher_->Fetch(
effective_pac_url, &pac_script_,
base::Bind(&ProxyScriptDecider::OnIOCompletion, base::Unretained(this)));
}
int ProxyScriptDecider::DoFetchPacScriptComplete(int result) {
DCHECK(fetch_pac_bytes_);
net_log_.EndEventWithNetErrorCode(
NetLog::TYPE_PROXY_SCRIPT_DECIDER_FETCH_PAC_SCRIPT, result);
if (result != OK)
return TryToFallbackPacSource(result);
next_state_ = STATE_VERIFY_PAC_SCRIPT;
return result;
}
int ProxyScriptDecider::DoVerifyPacScript() {
next_state_ = STATE_VERIFY_PAC_SCRIPT_COMPLETE;
// This is just a heuristic. Ideally we would try to parse the script.
if (fetch_pac_bytes_ && !LooksLikePacScript(pac_script_))
return ERR_PAC_SCRIPT_FAILED;
return OK;
}
int ProxyScriptDecider::DoVerifyPacScriptComplete(int result) {
if (result != OK)
return TryToFallbackPacSource(result);
const PacSource& pac_source = current_pac_source();
// Extract the current script data.
if (fetch_pac_bytes_) {
script_data_ = ProxyResolverScriptData::FromUTF16(pac_script_);
} else {
script_data_ = pac_source.type == PacSource::CUSTOM ?
ProxyResolverScriptData::FromURL(pac_source.url) :
ProxyResolverScriptData::ForAutoDetect();
}
// Let the caller know which automatic setting we ended up initializing the
// resolver for (there may have been multiple fallbacks to choose from.)
if (current_pac_source().type == PacSource::CUSTOM) {
effective_config_ =
ProxyConfig::CreateFromCustomPacURL(current_pac_source().url);
effective_config_.set_pac_mandatory(pac_mandatory_);
} else {
if (fetch_pac_bytes_) {
GURL auto_detected_url;
switch (current_pac_source().type) {
case PacSource::WPAD_DHCP:
auto_detected_url = dhcp_proxy_script_fetcher_->GetPacURL();
break;
case PacSource::WPAD_DNS:
auto_detected_url = GURL(kWpadUrl);
break;
default:
NOTREACHED();
}
effective_config_ =
ProxyConfig::CreateFromCustomPacURL(auto_detected_url);
} else {
// The resolver does its own resolution so we cannot know the
// URL. Just do the best we can and state that the configuration
// is to auto-detect proxy settings.
effective_config_ = ProxyConfig::CreateAutoDetect();
}
}
return OK;
}
int ProxyScriptDecider::TryToFallbackPacSource(int error) {
DCHECK_LT(error, 0);
if (current_pac_source_index_ + 1 >= pac_sources_.size()) {
// Nothing left to fall back to.
return error;
}
// Advance to next URL in our list.
++current_pac_source_index_;
net_log_.AddEvent(
NetLog::TYPE_PROXY_SCRIPT_DECIDER_FALLING_BACK_TO_NEXT_PAC_SOURCE);
if (quick_check_enabled_ && current_pac_source().type == PacSource::WPAD_DNS)
next_state_ = STATE_QUICK_CHECK;
else
next_state_ = GetStartState();
return OK;
}
ProxyScriptDecider::State ProxyScriptDecider::GetStartState() const {
return fetch_pac_bytes_ ? STATE_FETCH_PAC_SCRIPT : STATE_VERIFY_PAC_SCRIPT;
}
void ProxyScriptDecider::DetermineURL(const PacSource& pac_source,
GURL* effective_pac_url) {
DCHECK(effective_pac_url);
switch (pac_source.type) {
case PacSource::WPAD_DHCP:
break;
case PacSource::WPAD_DNS:
*effective_pac_url = GURL(kWpadUrl);
break;
case PacSource::CUSTOM:
*effective_pac_url = pac_source.url;
break;
}
}
const ProxyScriptDecider::PacSource&
ProxyScriptDecider::current_pac_source() const {
DCHECK_LT(current_pac_source_index_, pac_sources_.size());
return pac_sources_[current_pac_source_index_];
}
void ProxyScriptDecider::OnWaitTimerFired() {
OnIOCompletion(OK);
}
void ProxyScriptDecider::DidComplete() {
net_log_.EndEvent(NetLog::TYPE_PROXY_SCRIPT_DECIDER);
}
void ProxyScriptDecider::Cancel() {
DCHECK_NE(STATE_NONE, next_state_);
net_log_.AddEvent(NetLog::TYPE_CANCELLED);
switch (next_state_) {
case STATE_WAIT_COMPLETE:
wait_timer_.Stop();
break;
case STATE_FETCH_PAC_SCRIPT_COMPLETE:
proxy_script_fetcher_->Cancel();
break;
default:
NOTREACHED();
break;
}
// This is safe to call in any state.
if (dhcp_proxy_script_fetcher_)
dhcp_proxy_script_fetcher_->Cancel();
DidComplete();
}
} // namespace net