Bug 1392272 - P1: [windows] Monitor system proxy changes, r=necko-reviewers,dragana

Differential Revision: https://phabricator.services.mozilla.com/D127724

build/clang-plugin/ThreadAllows.txt

@@ -72,6 +72,7 @@ SpinEventLoop
 StressRunner
 SuicideManager
 SuicideThread
+System Proxy
 TEQ AwaitIdle
 TelemetryModule
 Test Thread

modules/libpref/init/StaticPrefList.yaml

@@ -9673,6 +9673,11 @@
   value: false
   mirror: always
 
+- name: network.proxy.detect_system_proxy_changes
+  type: RelaxedAtomicBool
+  value: false
+  mirror: always
+
 # Some requests during a page load are marked as "tail", mainly trackers, but not only.
 # This pref controls whether such requests are put to the tail, behind other requests
 # emerging during page loading process.

netwerk/base/ProxyConfig.h

@@ -0,0 +1,199 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_netwerk_base_proxy_config_h
+#define mozilla_netwerk_base_proxy_config_h
+
+#include <map>
+
+#include "nsCRT.h"
+#include "nsString.h"
+#include "nsTArray.h"
+
+// NOTE: This file is inspired by Chromium's code.
+// https://source.chromium.org/chromium/chromium/src/+/main:net/proxy_resolution/proxy_config.h.
+
+namespace mozilla {
+namespace net {
+
+// ProxyServer stores the {type, host, port} of a proxy server.
+// ProxyServer is immutable.
+class ProxyServer final {
+ public:
+  enum class ProxyType {
+    DIRECT = 0,
+    HTTP,
+    HTTPS,
+    SOCKS,
+    SOCKS4,
+    SOCKS5,
+    FTP,
+    // DEFAULT is a special type used on windows only.
+    DEFAULT
+  };
+
+  ProxyServer() = default;
+
+  ProxyServer(ProxyType aType, const nsACString& aHost, int32_t aPort)
+      : mType(aType), mHost(aHost), mPort(aPort) {}
+
+  const nsCString& Host() const { return mHost; }
+
+  int32_t Port() const { return mPort; }
+
+  ProxyType Type() const { return mType; }
+
+  void ToHostAndPortStr(nsACString& aOutput) {
+    aOutput.Truncate();
+    if (mType == ProxyType::DIRECT) {
+      return;
+    }
+
+    aOutput.Assign(mHost);
+    if (mPort != -1) {
+      aOutput.Append(':');
+      aOutput.AppendInt(mPort);
+    }
+  }
+
+  bool operator==(const ProxyServer& aOther) const {
+    return mType == aOther.mType && mHost == aOther.mHost &&
+           mPort == aOther.mPort;
+  }
+
+  bool operator!=(const ProxyServer& aOther) const {
+    return !(*this == aOther);
+  }
+
+ private:
+  ProxyType mType{ProxyType::DIRECT};
+  nsCString mHost;
+  int32_t mPort{-1};
+};
+
+// This class includes the information about proxy configuration.
+// It contains enabled proxy servers, exception list, and the url of PAC
+// script.
+class ProxyConfig {
+ public:
+  struct ProxyRules {
+    ProxyRules() = default;
+    ~ProxyRules() = default;
+
+    std::map<ProxyServer::ProxyType, ProxyServer> mProxyServers;
+  };
+
+  struct ProxyBypassRules {
+    ProxyBypassRules() = default;
+    ~ProxyBypassRules() = default;
+
+    CopyableTArray<nsCString> mExceptions;
+  };
+
+  ProxyConfig() = default;
+  ProxyConfig(const ProxyConfig& config);
+  ~ProxyConfig() = default;
+
+  ProxyRules& Rules() { return mRules; }
+
+  const ProxyRules& Rules() const { return mRules; }
+
+  ProxyBypassRules& ByPassRules() { return mBypassRules; }
+
+  const ProxyBypassRules& ByPassRules() const { return mBypassRules; }
+
+  void SetPACUrl(const nsACString& aUrl) { mPACUrl = aUrl; }
+
+  const nsCString& PACUrl() const { return mPACUrl; }
+
+  static ProxyServer::ProxyType ToProxyType(const char* aType) {
+    if (!aType) {
+      return ProxyServer::ProxyType::DIRECT;
+    }
+
+    if (nsCRT::strcasecmp(aType, "http") == 0) {
+      return ProxyServer::ProxyType::HTTP;
+    }
+    if (nsCRT::strcasecmp(aType, "https") == 0) {
+      return ProxyServer::ProxyType::HTTPS;
+    }
+    if (nsCRT::strcasecmp(aType, "socks") == 0) {
+      return ProxyServer::ProxyType::SOCKS;
+    }
+    if (nsCRT::strcasecmp(aType, "socks4") == 0) {
+      return ProxyServer::ProxyType::SOCKS4;
+    }
+    if (nsCRT::strcasecmp(aType, "socks5") == 0) {
+      return ProxyServer::ProxyType::SOCKS5;
+    }
+    if (nsCRT::strcasecmp(aType, "ftp") == 0) {
+      return ProxyServer::ProxyType::FTP;
+    }
+
+    return ProxyServer::ProxyType::DIRECT;
+  }
+
+  static void SetProxyResult(const char* aType, const nsACString& aHostPort,
+                             nsACString& aResult) {
+    aResult.AssignASCII(aType);
+    aResult.Append(' ');
+    aResult.Append(aHostPort);
+  }
+
+  static void SetProxyResultDirect(nsACString& aResult) {
+    // For whatever reason, a proxy is not to be used.
+    aResult.AssignLiteral("DIRECT");
+  }
+
+  static void ProxyStrToResult(const nsACString& aSpecificProxy,
+                               const nsACString& aDefaultProxy,
+                               const nsACString& aSocksProxy,
+                               nsACString& aResult) {
+    if (!aSpecificProxy.IsEmpty()) {
+      SetProxyResult("PROXY", aSpecificProxy,
+                     aResult);  // Protocol-specific proxy.
+    } else if (!aDefaultProxy.IsEmpty()) {
+      SetProxyResult("PROXY", aDefaultProxy, aResult);  // Default proxy.
+    } else if (!aSocksProxy.IsEmpty()) {
+      SetProxyResult("SOCKS", aSocksProxy, aResult);  // SOCKS proxy.
+    } else {
+      SetProxyResultDirect(aResult);  // Direct connection.
+    }
+  }
+
+  void GetProxyString(const nsACString& aScheme, nsACString& aResult) {
+    SetProxyResultDirect(aResult);
+
+    nsAutoCString specificProxy;
+    nsAutoCString defaultProxy;
+    nsAutoCString socksProxy;
+    nsAutoCString prefix;
+    ToLowerCase(aScheme, prefix);
+    ProxyServer::ProxyType type = ProxyConfig::ToProxyType(prefix.get());
+    for (auto& [key, value] : mRules.mProxyServers) {
+      // Break the loop if we found a specific proxy.
+      if (key == type) {
+        value.ToHostAndPortStr(specificProxy);
+        break;
+      } else if (key == ProxyServer::ProxyType::DEFAULT) {
+        value.ToHostAndPortStr(defaultProxy);
+      } else if (key == ProxyServer::ProxyType::SOCKS) {
+        value.ToHostAndPortStr(socksProxy);
+      }
+    }
+
+    ProxyStrToResult(specificProxy, defaultProxy, socksProxy, aResult);
+  }
+
+ private:
+  nsCString mPACUrl;
+  ProxyRules mRules;
+  ProxyBypassRules mBypassRules;
+};
+
+}  // namespace net
+}  // namespace mozilla
+
+#endif  // mozilla_netwerk_base_proxy_config_h

toolkit/system/windowsproxy/moz.build

@@ -16,3 +16,7 @@ XPCOM_MANIFESTS += [
 ]
 
 FINAL_LIBRARY = "xul"
+
+LOCAL_INCLUDES += [
+    "/netwerk/base",
+]

toolkit/system/windowsproxy/nsWindowsSystemProxySettings.cpp

@@ -6,30 +6,52 @@
 #include <windows.h>
 #include <ras.h>
 #include <wininet.h>
+#include <functional>
 
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/Attributes.h"
+#include "mozilla/Atomics.h"
 #include "nsISystemProxySettings.h"
 #include "mozilla/Components.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/Services.h"
 #include "mozilla/ProfilerLabels.h"
+#include "mozilla/StaticPrefs_network.h"
+#include "mozilla/Tokenizer.h"
+#include "mozilla/Unused.h"
+#include "nsComponentManagerUtils.h"
+#include "nsIObserver.h"
+#include "nsIObserverService.h"
+#include "nsIWindowsRegKey.h"
 #include "nsPrintfCString.h"
 #include "nsNetCID.h"
 #include "nsThreadUtils.h"
 #include "prnetdb.h"
 #include "ProxyUtils.h"
+#include "ProxyConfig.h"
 
-class nsWindowsSystemProxySettings final : public nsISystemProxySettings {
+using namespace mozilla::net;
+
+class nsWindowsSystemProxySettings : public nsISystemProxySettings {
  public:
   NS_DECL_THREADSAFE_ISUPPORTS
   NS_DECL_NSISYSTEMPROXYSETTINGS
 
   nsWindowsSystemProxySettings(){};
+  virtual nsresult Init() { return NS_OK; }
 
- private:
-  ~nsWindowsSystemProxySettings(){};
+ protected:
+  virtual ~nsWindowsSystemProxySettings() = default;
 
   bool MatchOverride(const nsACString& aHost);
+  bool MatchOverrideInternal(const nsACString& aHost,
+                             const nsACString& aOverrideRule);
   bool PatternMatch(const nsACString& aHost, const nsACString& aOverride);
+  nsresult ReadProxyRules(
+      uint32_t aOptions,
+      const std::function<bool(uint32_t aFlags)>& aFlagsHandler,
+      const std::function<void(const nsACString& aRule, bool& aContinue)>&
+          aRuleHandler);
 };
 
 NS_IMPL_ISUPPORTS(nsWindowsSystemProxySettings, nsISystemProxySettings)
@@ -43,18 +65,6 @@ nsWindowsSystemProxySettings::GetMainThreadOnly(bool* aMainThreadOnly) {
   return NS_OK;
 }
 
-static void SetProxyResult(const char* aType, const nsACString& aHostPort,
-                           nsACString& aResult) {
-  aResult.AssignASCII(aType);
-  aResult.Append(' ');
-  aResult.Append(aHostPort);
-}
-
-static void SetProxyResultDirect(nsACString& aResult) {
-  // For whatever reason, a proxy is not to be used.
-  aResult.AssignLiteral("DIRECT");
-}
-
 static nsresult ReadInternetOption(uint32_t aOption, uint32_t& aFlags,
                                    nsAString& aValue) {
   // Bug 1366133: InternetGetConnectedStateExW() may cause hangs
@@ -93,20 +103,8 @@ static nsresult ReadInternetOption(uint32_t aOption, uint32_t& aFlags,
   return NS_OK;
 }
 
-bool nsWindowsSystemProxySettings::MatchOverride(const nsACString& aHost) {
-  nsresult rv;
-  uint32_t flags = 0;
-  nsAutoString buf;
-
-  rv = ReadInternetOption(INTERNET_PER_CONN_PROXY_BYPASS, flags, buf);
-  if (NS_FAILED(rv)) return false;
-
-  NS_ConvertUTF16toUTF8 cbuf(buf);
-
-  nsAutoCString host(aHost);
-  int32_t start = 0;
-  int32_t end = cbuf.Length();
-
+bool nsWindowsSystemProxySettings::MatchOverrideInternal(
+    const nsACString& aHost, const nsACString& aOverrideRule) {
   // Windows formats its proxy override list in the form:
   // server;server;server where 'server' is a server name pattern or IP
   // address, or "<local>". "<local>" must be translated to
@@ -114,26 +112,73 @@ bool nsWindowsSystemProxySettings::MatchOverride(const nsACString& aHost) {
   // In a server name pattern, a '*' character matches any substring and
   // all other characters must match themselves; the whole pattern must match
   // the whole hostname.
+  nsAutoCString host(aHost);
+  if (aOverrideRule.EqualsLiteral("<local>")) {
+    PRNetAddr addr;
+    bool isIpAddr = (PR_StringToNetAddr(host.get(), &addr) == PR_SUCCESS);
+
+    // Don't use proxy for local hosts (plain hostname, no dots)
+    if (!isIpAddr && !host.Contains('.')) {
+      return true;
+    }
+
+    if (host.EqualsLiteral("127.0.0.1") || host.EqualsLiteral("::1")) {
+      return true;
+    }
+  } else if (PatternMatch(host, aOverrideRule)) {
+    return true;
+  }
+
+  return false;
+}
+
+bool nsWindowsSystemProxySettings::MatchOverride(const nsACString& aHost) {
+  nsAutoCString host(aHost);
+  bool foundMatch = false;
+
+  auto flagHandler = [](uint32_t aFlags) { return true; };
+  auto ruleHandler = [&](const nsACString& aOverrideRule, bool& aContinue) {
+    foundMatch = MatchOverrideInternal(aHost, aOverrideRule);
+    if (foundMatch) {
+      aContinue = false;
+    }
+  };
+
+  ReadProxyRules(INTERNET_PER_CONN_PROXY_BYPASS, flagHandler, ruleHandler);
+  return foundMatch;
+}
+
+nsresult nsWindowsSystemProxySettings::ReadProxyRules(
+    uint32_t aOptions,
+    const std::function<bool(uint32_t aFlags)>& aFlagsHandler,
+    const std::function<void(const nsACString& aRule, bool& aContinue)>&
+        aRuleHandler) {
+  uint32_t flags = 0;
+  nsAutoString buf;
+
+  nsresult rv = ReadInternetOption(aOptions, flags, buf);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  if (!aFlagsHandler(flags)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  NS_ConvertUTF16toUTF8 cbuf(buf);
+
+  int32_t start = 0;
+  int32_t end = cbuf.Length();
   while (true) {
     int32_t delimiter = cbuf.FindCharInSet(" ;", start);
     if (delimiter == -1) delimiter = end;
 
     if (delimiter != start) {
-      const nsAutoCString override(Substring(cbuf, start, delimiter - start));
-      if (override.EqualsLiteral("<local>")) {
-        PRNetAddr addr;
-        bool isIpAddr = (PR_StringToNetAddr(host.get(), &addr) == PR_SUCCESS);
-
-        // Don't use proxy for local hosts (plain hostname, no dots)
-        if (!isIpAddr && !host.Contains('.')) {
-          return true;
-        }
-
-        if (host.EqualsLiteral("127.0.0.1") || host.EqualsLiteral("::1")) {
-          return true;
-        }
-      } else if (PatternMatch(host, override)) {
-        return true;
+      const nsAutoCString rule(Substring(cbuf, start, delimiter - start));
+      bool continueProcessing = false;
+      aRuleHandler(rule, continueProcessing);
+      if (!continueProcessing) {
+        return NS_OK;
       }
     }
 
@@ -141,7 +186,7 @@ bool nsWindowsSystemProxySettings::MatchOverride(const nsACString& aHost) {
     start = ++delimiter;
   }
 
-  return false;
+  return NS_OK;
 }
 
 bool nsWindowsSystemProxySettings::PatternMatch(const nsACString& aHost,
@@ -170,78 +215,322 @@ nsresult nsWindowsSystemProxySettings::GetProxyForURI(const nsACString& aSpec,
                                                       const nsACString& aHost,
                                                       const int32_t aPort,
                                                       nsACString& aResult) {
-  nsresult rv;
-  uint32_t flags = 0;
-  nsAutoString buf;
+  auto flagHandler = [&](uint32_t aFlags) {
+    if (!(aFlags & PROXY_TYPE_PROXY)) {
+      ProxyConfig::SetProxyResultDirect(aResult);
+      return false;
+    }
 
-  rv = ReadInternetOption(INTERNET_PER_CONN_PROXY_SERVER, flags, buf);
-  if (NS_FAILED(rv) || !(flags & PROXY_TYPE_PROXY)) {
-    SetProxyResultDirect(aResult);
-    return NS_OK;
-  }
+    if (MatchOverride(aHost)) {
+      ProxyConfig::SetProxyResultDirect(aResult);
+      return false;
+    }
 
-  if (MatchOverride(aHost)) {
-    SetProxyResultDirect(aResult);
-    return NS_OK;
-  }
-
-  NS_ConvertUTF16toUTF8 cbuf(buf);
+    return true;
+  };
 
   constexpr auto kSocksPrefix = "socks="_ns;
   nsAutoCString prefix;
   ToLowerCase(aScheme, prefix);
-
   prefix.Append('=');
 
   nsAutoCString specificProxy;
   nsAutoCString defaultProxy;
   nsAutoCString socksProxy;
-  int32_t start = 0;
-  int32_t end = cbuf.Length();
 
-  while (true) {
-    int32_t delimiter = cbuf.FindCharInSet(" ;", start);
-    if (delimiter == -1) delimiter = end;
+  auto ruleHandler = [&](const nsACString& aRule, bool& aContinue) {
+    const nsCString proxy(aRule);
+    aContinue = true;
+    if (proxy.FindChar('=') == -1) {
+      // If a proxy name is listed by itself, it is used as the
+      // default proxy for any protocols that do not have a specific
+      // proxy specified.
+      // (http://msdn.microsoft.com/en-us/library/aa383996%28VS.85%29.aspx)
+      defaultProxy = proxy;
+    } else if (proxy.Find(prefix) == 0) {
+      // To list a proxy for a specific protocol, the string must
+      // follow the format "<protocol>=<protocol>://<proxy_name>".
+      // (http://msdn.microsoft.com/en-us/library/aa383996%28VS.85%29.aspx)
+      specificProxy = Substring(proxy, prefix.Length());
+      aContinue = false;
+    } else if (proxy.Find(kSocksPrefix) == 0) {
+      // SOCKS proxy.
+      socksProxy = Substring(proxy, kSocksPrefix.Length());  // "socks=" length.
+    }
+  };
 
-    if (delimiter != start) {
-      const nsAutoCString proxy(Substring(cbuf, start, delimiter - start));
-      if (proxy.FindChar('=') == -1) {
-        // If a proxy name is listed by itself, it is used as the
-        // default proxy for any protocols that do not have a specific
-        // proxy specified.
-        // (http://msdn.microsoft.com/en-us/library/aa383996%28VS.85%29.aspx)
-        defaultProxy = proxy;
-      } else if (proxy.Find(prefix) == 0) {
-        // To list a proxy for a specific protocol, the string must
-        // follow the format "<protocol>=<protocol>://<proxy_name>".
-        // (http://msdn.microsoft.com/en-us/library/aa383996%28VS.85%29.aspx)
-        specificProxy = Substring(proxy, prefix.Length());
+  nsresult rv =
+      ReadProxyRules(INTERNET_PER_CONN_PROXY_SERVER, flagHandler, ruleHandler);
+  if (NS_FAILED(rv)) {
+    ProxyConfig::SetProxyResultDirect(aResult);
+    return rv;
+  }
+
+  ProxyConfig::ProxyStrToResult(specificProxy, defaultProxy, socksProxy,
+                                aResult);
+  return NS_OK;
+}
+
+class WindowsSystemProxySettingsAsync final
+    : public nsWindowsSystemProxySettings,
+      public nsIObserver {
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSISYSTEMPROXYSETTINGS
+  NS_DECL_NSIOBSERVER
+
+  WindowsSystemProxySettingsAsync();
+  nsresult Init() override;
+
+ private:
+  virtual ~WindowsSystemProxySettingsAsync();
+  void ThreadFunc();
+  void OnProxyConfigChangedInternal();
+
+  ProxyConfig mConfig;
+  nsCOMPtr<nsIThread> mBackgroundThread;
+  mozilla::Mutex mLock{"WindowsSystemProxySettingsAsync"};
+  mozilla::Atomic<bool> mInited{false};
+  mozilla::Atomic<bool> mTerminated{false};
+};
+
+NS_IMPL_ISUPPORTS_INHERITED(WindowsSystemProxySettingsAsync,
+                            nsWindowsSystemProxySettings, nsIObserver);
+
+WindowsSystemProxySettingsAsync::WindowsSystemProxySettingsAsync() = default;
+
+WindowsSystemProxySettingsAsync::~WindowsSystemProxySettingsAsync() = default;
+
+nsresult WindowsSystemProxySettingsAsync::Init() {
+  nsCOMPtr<nsIObserverService> observerService =
+      mozilla::services::GetObserverService();
+  if (!observerService) {
+    return NS_ERROR_FAILURE;
+  }
+  observerService->AddObserver(this, "xpcom-shutdown-threads", false);
+
+  nsCOMPtr<nsIThread> thread;
+  if (NS_FAILED(NS_NewNamedThread("System Proxy", getter_AddRefs(thread)))) {
+    NS_WARNING("NS_NewNamedThread failed!");
+    return NS_ERROR_FAILURE;
+  }
+
+  mBackgroundThread = std::move(thread);
+
+  nsCOMPtr<nsIRunnable> event = mozilla::NewRunnableMethod(
+      "WindowsSystemProxySettingsAsync::ThreadFunc", this,
+      &WindowsSystemProxySettingsAsync::ThreadFunc);
+  return mBackgroundThread->Dispatch(event, nsIEventTarget::DISPATCH_NORMAL);
+}
+
+NS_IMETHODIMP
+WindowsSystemProxySettingsAsync::Observe(nsISupports* aSubject,
+                                         const char* aTopic,
+                                         const char16_t* aData) {
+  if (!strcmp(aTopic, "xpcom-shutdown-threads")) {
+    if (mBackgroundThread) {
+      mTerminated = true;
+      nsCOMPtr<nsIThread> thread;
+      {
+        mozilla::MutexAutoLock lock(mLock);
+        thread = mBackgroundThread.get();
+        mBackgroundThread = nullptr;
+      }
+      MOZ_ALWAYS_SUCCEEDS(thread->Shutdown());
+    }
+  }
+  return NS_OK;
+}
+
+void WindowsSystemProxySettingsAsync::ThreadFunc() {
+  nsresult rv;
+  nsCOMPtr<nsIWindowsRegKey> regKey =
+      do_CreateInstance("@mozilla.org/windows-registry-key;1", &rv);
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  rv = regKey->Open(
+      nsIWindowsRegKey::ROOT_KEY_CURRENT_USER,
+      u"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Internet Settings"_ns,
+      nsIWindowsRegKey::ACCESS_READ);
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  OnProxyConfigChangedInternal();
+
+  rv = regKey->StartWatching(true);
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  mInited = true;
+
+  while (!mTerminated) {
+    bool changed = false;
+    regKey->HasChanged(&changed);
+    if (changed) {
+      OnProxyConfigChangedInternal();
+    }
+  }
+}
+
+void WindowsSystemProxySettingsAsync::OnProxyConfigChangedInternal() {
+  ProxyConfig config;
+
+  // PAC
+  nsAutoCString pacUrl;
+  if (NS_SUCCEEDED(GetPACURI(pacUrl))) {
+    config.SetPACUrl(pacUrl);
+  }
+
+  // proxies
+  auto flagHandler = [&](uint32_t aFlags) {
+    if (!(aFlags & PROXY_TYPE_PROXY)) {
+      return false;
+    }
+    return true;
+  };
+
+  // The format of input string is like: scheme=host:port, e.g.
+  // "http=127.0.0.1:3128".
+  auto processProxyStr = [](const nsCString& aInput,
+                            ProxyServer::ProxyType& aOutType,
+                            nsACString& aOutHost, int32_t& aOutPort) {
+    aOutType = ProxyServer::ProxyType::DEFAULT;
+    aOutHost = EmptyCString();
+    aOutPort = -1;
+
+    mozilla::Tokenizer t(aInput);
+    mozilla::Tokenizer::Token token;
+    // skip over spaces
+    t.SkipWhites();
+    t.Record();
+
+    bool parsingIPv6 = false;
+    bool parsingPort = false;
+    while (t.Next(token)) {
+      if (token.Equals(mozilla::Tokenizer::Token::EndOfFile())) {
+        if (aOutHost.IsEmpty()) {
+          t.Claim(aOutHost);
+        }
         break;
-      } else if (proxy.Find(kSocksPrefix) == 0) {
-        // SOCKS proxy.
-        socksProxy =
-            Substring(proxy, kSocksPrefix.Length());  // "socks=" length.
+      }
+
+      if (token.Equals(mozilla::Tokenizer::Token::Char('='))) {
+        nsAutoCString typeStr;
+        t.Claim(typeStr);
+        aOutType = ProxyConfig::ToProxyType(typeStr.get());
+        t.Record();
+      }
+
+      if (token.Equals(mozilla::Tokenizer::Token::Char('['))) {
+        parsingIPv6 = true;
+        continue;
+      }
+
+      if (!parsingIPv6 && token.Equals(mozilla::Tokenizer::Token::Char(':'))) {
+        // Port is starting. Claim the previous as host.
+        t.Claim(aOutHost);
+        t.Record();
+        parsingPort = true;
+        continue;
+      }
+
+      if (token.Equals(mozilla::Tokenizer::Token::Char(']'))) {
+        parsingIPv6 = false;
+        continue;
       }
     }
 
-    if (delimiter == end) break;
-    start = ++delimiter;
+    if (parsingPort) {
+      nsAutoCString portStr;
+      t.Claim(portStr);
+      nsresult rv = NS_OK;
+      aOutPort = portStr.ToInteger(&rv);
+      if (NS_FAILED(rv)) {
+        aOutPort = -1;
+      }
+    }
+  };
+
+  auto ruleHandler = [&](const nsACString& aRule, bool& aContinue) {
+    const nsCString proxy(aRule);
+    aContinue = true;
+    ProxyServer::ProxyType type;
+    nsCString host;
+    int32_t port = -1;
+    processProxyStr(proxy, type, host, port);
+    if (!host.IsEmpty()) {
+      ProxyServer server(type, host, port);
+      config.Rules().mProxyServers[server.Type()] = std::move(server);
+    }
+  };
+
+  // Note that reading the proxy settings from registry directly is not
+  // documented by Microsoft, so doing it could be risky. We still use system
+  // API to read proxy settings for safe.
+  ReadProxyRules(INTERNET_PER_CONN_PROXY_SERVER, flagHandler, ruleHandler);
+
+  auto bypassRuleHandler = [&](const nsACString& aOverrideRule,
+                               bool& aContinue) {
+    aContinue = true;
+    config.ByPassRules().mExceptions.AppendElement(aOverrideRule);
+  };
+
+  auto dummyHandler = [](uint32_t aFlags) { return true; };
+  ReadProxyRules(INTERNET_PER_CONN_PROXY_BYPASS, dummyHandler,
+                 bypassRuleHandler);
+
+  {
+    mozilla::MutexAutoLock lock(mLock);
+    mConfig = std::move(config);
+  }
+}
+
+NS_IMETHODIMP
+WindowsSystemProxySettingsAsync::GetMainThreadOnly(bool* aMainThreadOnly) {
+  return nsWindowsSystemProxySettings::GetMainThreadOnly(aMainThreadOnly);
+}
+
+NS_IMETHODIMP WindowsSystemProxySettingsAsync::GetPACURI(nsACString& aResult) {
+  AUTO_PROFILER_LABEL("WindowsSystemProxySettingsAsync::GetPACURI", OTHER);
+  mozilla::MutexAutoLock lock(mLock);
+  aResult.Assign(mConfig.PACUrl());
+  return NS_OK;
+}
+
+NS_IMETHODIMP WindowsSystemProxySettingsAsync::GetProxyForURI(
+    const nsACString& aSpec, const nsACString& aScheme, const nsACString& aHost,
+    const int32_t aPort, nsACString& aResult) {
+  // Fallback to nsWindowsSystemProxySettings::GetProxyForURI if we failed to
+  // monitor the change of registry keys.
+  if (!mInited) {
+    return nsWindowsSystemProxySettings::GetProxyForURI(aSpec, aScheme, aHost,
+                                                        aPort, aResult);
   }
 
-  if (!specificProxy.IsEmpty())
-    SetProxyResult("PROXY", specificProxy,
-                   aResult);  // Protocol-specific proxy.
-  else if (!defaultProxy.IsEmpty())
-    SetProxyResult("PROXY", defaultProxy, aResult);  // Default proxy.
-  else if (!socksProxy.IsEmpty())
-    SetProxyResult("SOCKS", socksProxy, aResult);  // SOCKS proxy.
-  else
-    SetProxyResultDirect(aResult);  // Direct connection.
+  mozilla::MutexAutoLock lock(mLock);
 
+  for (const auto& bypassRule : mConfig.ByPassRules().mExceptions) {
+    if (MatchOverrideInternal(aHost, bypassRule)) {
+      ProxyConfig::SetProxyResultDirect(aResult);
+      return NS_OK;
+    }
+  }
+
+  mConfig.GetProxyString(aScheme, aResult);
   return NS_OK;
 }
 
 NS_IMPL_COMPONENT_FACTORY(nsWindowsSystemProxySettings) {
-  return mozilla::MakeAndAddRef<nsWindowsSystemProxySettings>()
-      .downcast<nsISupports>();
+  auto settings =
+      mozilla::StaticPrefs::network_proxy_detect_system_proxy_changes()
+          ? mozilla::MakeRefPtr<WindowsSystemProxySettingsAsync>()
+          : mozilla::MakeRefPtr<nsWindowsSystemProxySettings>();
+  if (NS_SUCCEEDED(settings->Init())) {
+    return settings.forget().downcast<nsISupports>();
+  }
+  return nullptr;
 }