VPN-4227: Windows daemon recovery on crash

src/daemon/daemon.cpp

@@ -79,7 +79,7 @@ bool Daemon::activate(const InterfaceConfig& config) {
         return false;
       }
 
-      if (supportDnsUtils() && !dnsutils()->restoreResolvers()) {
+      if (!dnsutils()->restoreResolvers()) {
         return false;
       }
 
@@ -161,10 +161,6 @@ bool Daemon::activate(const InterfaceConfig& config) {
 }
 
 bool Daemon::maybeUpdateResolvers(const InterfaceConfig& config) {
-  if (!supportDnsUtils()) {
-    return true;
-  }
-
   if ((config.m_hopType == InterfaceConfig::MultiHopExit) ||
       (config.m_hopType == InterfaceConfig::SingleHop)) {
     QList<QHostAddress> resolvers;
@@ -348,13 +344,8 @@ bool Daemon::deactivate(bool emitSignals) {
   }
 
   // Cleanup DNS
-  if (supportDnsUtils() && !dnsutils()->restoreResolvers()) {
-    return false;
-  }
-
-  if (!wgutils()->interfaceExists()) {
-    logger.warning() << "Wireguard interface does not exist.";
-    return false;
+  if (!dnsutils()->restoreResolvers()) {
+    logger.warning() << "Failed to restore DNS resolvers.";
   }
 
   // Cleanup peers and routing
@@ -366,14 +357,10 @@ bool Daemon::deactivate(bool emitSignals) {
     }
     wgutils()->deletePeer(config);
   }
+  m_connections.clear();
 
   // Delete the interface
-  if (!wgutils()->deleteInterface()) {
-    return false;
-  }
-
-  m_connections.clear();
-  return true;
+  return wgutils()->deleteInterface();
 }
 
 QString Daemon::logs() {

src/daemon/daemon.h

@@ -65,7 +65,6 @@ class Daemon : public QObject {
   virtual WireguardUtils* wgutils() const = 0;
   virtual bool supportIPUtils() const { return false; }
   virtual IPUtils* iputils() { return nullptr; }
-  virtual bool supportDnsUtils() const { return false; }
   virtual DnsUtils* dnsutils() { return nullptr; }
 
   static bool parseStringList(const QJsonObject& obj, const QString& name,

src/localsocketcontroller.cpp

@@ -46,7 +46,7 @@ LocalSocketController::LocalSocketController() {
   connect(m_socket, &QLocalSocket::connected, this,
           &LocalSocketController::daemonConnected);
   connect(m_socket, &QLocalSocket::disconnected, this,
-          &LocalSocketController::disconnected);
+          [&] { errorOccurred(QLocalSocket::PeerClosedError); });
   connect(m_socket, &QLocalSocket::errorOccurred, this,
           &LocalSocketController::errorOccurred);
   connect(m_socket, &QLocalSocket::readyRead, this,

src/platforms/linux/daemon/dbusservice.h

@@ -46,7 +46,6 @@ class DBusService final : public Daemon, protected QDBusContext {
   WireguardUtils* wgutils() const override { return m_wgutils; }
   bool supportIPUtils() const override { return true; }
   IPUtils* iputils() override;
-  bool supportDnsUtils() const override { return true; }
   DnsUtils* dnsutils() override;
 
  private:

src/platforms/macos/daemon/macosdaemon.h

@@ -21,7 +21,6 @@ class MacOSDaemon final : public Daemon {
 
  protected:
   WireguardUtils* wgutils() const override { return m_wgutils; }
-  bool supportDnsUtils() const override { return true; }
   DnsUtils* dnsutils() override { return m_dnsutils; }
   bool supportIPUtils() const override { return true; }
   IPUtils* iputils() override { return m_iputils; }

src/platforms/windows/daemon/dnsutilswindows.cpp

@@ -4,8 +4,11 @@
 
 #include "dnsutilswindows.h"
 
+#include <WS2tcpip.h>
 #include <iphlpapi.h>
 #include <windows.h>
+#include <winsock2.h>
+#include <ws2ipdef.h>
 
 #include <QProcess>
 #include <QTextStream>
@@ -39,30 +42,27 @@ DnsUtilsWindows::~DnsUtilsWindows() {
 
 bool DnsUtilsWindows::updateResolvers(const QString& ifname,
                                       const QList<QHostAddress>& resolvers) {
-  NET_LUID luid;
-  if (ConvertInterfaceAliasToLuid((wchar_t*)ifname.utf16(), &luid) != 0) {
+  MIB_IF_ROW2 entry;
+  if (ConvertInterfaceAliasToLuid((wchar_t*)ifname.utf16(),
+                                  &entry.InterfaceLuid) != 0) {
     logger.error() << "Failed to resolve LUID for" << ifname;
     return false;
   }
-  m_luid = luid.Value;
+  if (GetIfEntry2(&entry) != NO_ERROR) {
+    logger.error() << "Failed to resolve interface for" << ifname;
+    return false;
+  }
+  m_luid = entry.InterfaceLuid.Value;
 
   logger.debug() << "Configuring DNS for" << ifname;
   if (m_setInterfaceDnsSettingsProcAddr == nullptr) {
-    return updateResolversNetsh(resolvers);
+    return updateResolversNetsh(entry.InterfaceIndex, resolvers);
   }
-  return updateResolversWin32(resolvers);
+  return updateResolversWin32(entry.InterfaceGuid, resolvers);
 }
 
 bool DnsUtilsWindows::updateResolversWin32(
-    const QList<QHostAddress>& resolvers) {
-  GUID guid;
-  NET_LUID luid;
-  luid.Value = m_luid;
-  if (ConvertInterfaceLuidToGuid(&luid, &guid) != NO_ERROR) {
-    logger.error() << "Failed to resolve GUID";
-    return false;
-  }
-
+    GUID guid, const QList<QHostAddress>& resolvers) {
   QStringList v4resolvers;
   QStringList v6resolvers;
   for (const QHostAddress& addr : resolvers) {
@@ -113,16 +113,8 @@ constexpr const char* netshAddTemplate =
     "interface %1 add dnsservers name=%2 address=%3 validate=no\r\n";
 
 bool DnsUtilsWindows::updateResolversNetsh(
-    const QList<QHostAddress>& resolvers) {
+    int ifindex, const QList<QHostAddress>& resolvers) {
   QProcess netsh;
-  NET_LUID luid;
-  NET_IFINDEX ifindex;
-  luid.Value = m_luid;
-  if (ConvertInterfaceLuidToIndex(&luid, &ifindex) != NO_ERROR) {
-    logger.error() << "Failed to resolve GUID";
-    return false;
-  }
-
   netsh.setProgram("netsh");
   netsh.start();
   if (!netsh.waitForStarted(WINDOWS_NETSH_TIMEOUT_MSEC)) {
@@ -166,12 +158,26 @@ bool DnsUtilsWindows::updateResolversNetsh(
 
 bool DnsUtilsWindows::restoreResolvers() {
   if (m_luid == 0) {
+    // If the DNS hasn't been configured, there is nothing to restore.
+    return true;
+  }
+
+  MIB_IF_ROW2 entry;
+  DWORD error;
+  entry.InterfaceLuid.Value = m_luid;
+  error = GetIfEntry2(&entry);
+  if (error == ERROR_FILE_NOT_FOUND) {
+    // If the interface no longer exists, there is nothing to restore.
     return true;
   }
+  if (error != NO_ERROR) {
+    logger.error() << "Failed to resolve interface entry:" << error;
+    return false;
+  }
 
   QList<QHostAddress> empty;
   if (m_setInterfaceDnsSettingsProcAddr == nullptr) {
-    return updateResolversNetsh(empty);
+    return updateResolversNetsh(entry.InterfaceIndex, empty);
   }
-  return updateResolversWin32(empty);
+  return updateResolversWin32(entry.InterfaceGuid, empty);
 }

src/platforms/windows/daemon/dnsutilswindows.h

@@ -27,8 +27,8 @@ class DnsUtilsWindows final : public DnsUtils {
   quint64 m_luid = 0;
   DWORD (*m_setInterfaceDnsSettingsProcAddr)(GUID, const void*) = nullptr;
 
-  bool updateResolversWin32(const QList<QHostAddress>& resolvers);
-  bool updateResolversNetsh(const QList<QHostAddress>& resolvers);
+  bool updateResolversWin32(GUID, const QList<QHostAddress>& resolvers);
+  bool updateResolversNetsh(int ifindex, const QList<QHostAddress>& resolvers);
 };
 
 #endif  // DNSUTILSWINDOWS_H

src/platforms/windows/daemon/windowsdaemon.h

@@ -25,7 +25,6 @@ class WindowsDaemon final : public Daemon {
  protected:
   bool run(Op op, const InterfaceConfig& config) override;
   WireguardUtils* wgutils() const override { return m_wgutils; }
-  bool supportDnsUtils() const override { return true; }
   DnsUtils* dnsutils() override { return m_dnsutils; }
 
  private:

src/platforms/windows/daemon/windowstunnelservice.cpp

@@ -30,12 +30,22 @@ static bool waitForServiceStatus(SC_HANDLE service, DWORD expectedStatus);
 
 WindowsTunnelService::WindowsTunnelService(QObject* parent) : QObject(parent) {
   MZ_COUNT_CTOR(WindowsTunnelService);
+  logger.debug() << "WindowsTunnelService created.";
 
   m_scm = OpenSCManager(nullptr, nullptr, SC_MANAGER_ALL_ACCESS);
   if (m_scm == nullptr) {
     WindowsUtils::windowsLog("Failed to open SCManager");
   }
 
+  // Is the service already running? Terminate it.
+  SC_HANDLE service =
+      OpenService((SC_HANDLE)m_scm, TUNNEL_SERVICE_NAME, SERVICE_ALL_ACCESS);
+  if (service != nullptr) {
+    logger.info() << "Tunnel already exists. Terminating it.";
+    stopAndDeleteTunnelService(service);
+    CloseServiceHandle(service);
+  }
+
   connect(&m_timer, &QTimer::timeout, this, &WindowsTunnelService::timeout);
 }
 

src/platforms/windows/windowscommons.cpp

@@ -20,8 +20,6 @@
 #include "logger.h"
 #include "platforms/windows/windowsutils.h"
 
-#define TUNNEL_SERVICE_NAME L"WireGuardTunnel$mozvpn"
-
 constexpr const char* VPN_NAME = "MozillaVPN";
 constexpr const char* WIREGUARD_DIR = "WireGuard";
 constexpr const char* DATA_DIR = "Data";