Merge branch 'check-tap-ipv6'

20 files changed, 540 insertions, 120 deletions

diff --git a/talpid-core/src/lib.rs b/talpid-core/src/lib.rs
index ecc530aec3..54e3ef08ef 100644
--- a/talpid-core/src/lib.rs
+++ b/talpid-core/src/lib.rs
@@ -35,6 +35,8 @@ extern crate uuid;
 #[cfg(target_os = "linux")]
 extern crate which;
 #[cfg(windows)]
+extern crate widestring;
+#[cfg(windows)]
 extern crate winreg;
 
 extern crate openvpn_plugin;
@@ -45,6 +47,9 @@ extern crate talpid_types;
 #[macro_use]
 extern crate nftnl;
 
+#[cfg(windows)]
+mod winnet;
+
 /// Working with processes.
 pub mod process;
 
diff --git a/talpid-core/src/security/windows/dns.rs b/talpid-core/src/security/windows/dns.rs
index d068cb4151..4904946c98 100644
--- a/talpid-core/src/security/windows/dns.rs
+++ b/talpid-core/src/security/windows/dns.rs
@@ -1,16 +1,14 @@
-extern crate widestring;
-
-use super::ffi;
-use super::system_state::SystemStateWriter;
-
-use self::widestring::WideCString;
-use libc;
 use std::net::IpAddr;
 use std::path::Path;
 use std::ptr;
 use std::slice;
 
 use error_chain::ChainedError;
+use libc;
+use widestring::WideCString;
+
+use super::system_state::SystemStateWriter;
+use winnet;
 
 const DNS_STATE_FILENAME: &'static str = "dns-state-backup";
 
@@ -49,7 +47,7 @@ pub struct WinDns {
 
 impl WinDns {
     pub fn new<P: AsRef<Path>>(cache_dir: P) -> Result<Self> {
-        unsafe { WinDns_Initialize(Some(ffi::error_sink), ptr::null_mut()).into_result()? };
+        unsafe { WinDns_Initialize(Some(winnet::error_sink), ptr::null_mut()).into_result()? };
 
         let backup_writer = SystemStateWriter::new(
             cache_dir
@@ -191,7 +189,7 @@ extern "system" {
 
     #[link_name(WinDns_Initialize)]
     pub fn WinDns_Initialize(
-        sink: Option<ffi::ErrorSink>,
+        sink: Option<winnet::ErrorSink>,
         sink_context: *mut libc::c_void,
     ) -> InitializationResult;
 
diff --git a/talpid-core/src/security/windows/ffi.rs b/talpid-core/src/security/windows/ffi.rs
index 029989359e..2362876897 100644
--- a/talpid-core/src/security/windows/ffi.rs
+++ b/talpid-core/src/security/windows/ffi.rs
@@ -1,16 +1,3 @@
-use libc::{c_char, c_void};
-
-pub type ErrorSink = extern "system" fn(msg: *const c_char, ctx: *mut c_void);
-
-pub extern "system" fn error_sink(msg: *const c_char, _ctx: *mut c_void) {
-    use std::ffi::CStr;
-    if msg.is_null() {
-        error!("Log message from FFI boundary is NULL");
-    } else {
-        error!("{}", unsafe { CStr::from_ptr(msg).to_string_lossy() });
-    }
-}
-
 #[macro_export]
 macro_rules! ffi_error {
     ($result:ident, $error:expr) => {
diff --git a/talpid-core/src/security/windows/mod.rs b/talpid-core/src/security/windows/mod.rs
index e762a4887a..6ecca8988b 100644
--- a/talpid-core/src/security/windows/mod.rs
+++ b/talpid-core/src/security/windows/mod.rs
@@ -1,24 +1,21 @@
-extern crate widestring;
-
-use super::{NetworkSecurityT, SecurityPolicy};
 use std::net::IpAddr;
 use std::path::Path;
 use std::ptr;
 
-use self::winfw::*;
 use talpid_types::net::Endpoint;
+use widestring::WideCString;
 
-use self::widestring::WideCString;
-
+use self::dns::WinDns;
+use self::winfw::*;
+use super::{NetworkSecurityT, SecurityPolicy};
+use winnet;
 
 #[macro_use]
 mod ffi;
+
 mod dns;
-mod route;
 mod system_state;
 
-use self::dns::WinDns;
-
 error_chain! {
     errors {
         /// Failure to initialize windows firewall module
@@ -50,11 +47,15 @@ error_chain! {
         ResettingPolicy {
             description("Failed to reset firewall policies")
         }
+
+        /// Failure to set TAP adapter metric
+        SetTapMetric {
+            description("Unable to set TAP adapter metric")
+        }
     }
 
     links {
         WinDns(dns::Error, dns::ErrorKind) #[doc = "WinDNS failure"];
-        WinRoute(route::Error, route::ErrorKind) #[doc = "Failure to modify system routing metrics"];
     }
 }
 
@@ -73,7 +74,7 @@ impl NetworkSecurityT for NetworkSecurity {
         unsafe {
             WinFw_Initialize(
                 WINFW_TIMEOUT_SECONDS,
-                Some(ffi::error_sink),
+                Some(winnet::error_sink),
                 ptr::null_mut(),
             ).into_result()?
         };
@@ -168,14 +169,15 @@ impl NetworkSecurity {
 
         self.dns.set_dns(&vec![tunnel_metadata.gateway.into()])?;
 
-        let metrics_set = route::ensure_top_metric_for_interface(&tunnel_metadata.interface)?;
+        let metrics_set = winnet::ensure_top_metric_for_interface(&tunnel_metadata.interface)
+            .chain_err(|| ErrorKind::SetTapMetric)?;
+
         if metrics_set {
             debug!("Network interface metrics were changed");
         } else {
             debug!("Network interface metrics were not changed");
         }
 
-
         unsafe {
             WinFw_ApplyPolicyConnected(
                 winfw_settings,
@@ -195,10 +197,12 @@ impl NetworkSecurity {
 
 #[allow(non_snake_case)]
 mod winfw {
-    use super::{ffi, ErrorKind, Result};
     use libc;
     use talpid_types::net::TransportProtocol;
 
+    use super::{ErrorKind, Result};
+    use winnet;
+
     #[repr(C)]
     pub struct WinFwRelay {
         pub ip: *const libc::wchar_t,
@@ -254,7 +258,7 @@ mod winfw {
         #[link_name(WinFw_Initialize)]
         pub fn WinFw_Initialize(
             timeout: libc::c_uint,
-            sink: Option<ffi::ErrorSink>,
+            sink: Option<winnet::ErrorSink>,
             sink_context: *mut libc::c_void,
         ) -> InitializationResult;
 
diff --git a/talpid-core/src/security/windows/route.rs b/talpid-core/src/security/windows/route.rs
deleted file mode 100644
index 6ecf336956..0000000000
--- a/talpid-core/src/security/windows/route.rs
+++ /dev/null
@@ -1,63 +0,0 @@
-use super::ffi;
-use super::widestring::WideCString;
-use libc;
-use std::ptr;
-
-error_chain!{
-    errors{
-        /// Failure to set metrics of network interfaces
-        MetricApplication{
-            description("Failed to set the metrics for a network interface")
-        }
-        InvalidInterfaceAlias{
-            description("Supplied interface alias is invalid")
-        }
-    }
-}
-
-/// Returns true if metrics were changed, false otherwise
-pub fn ensure_top_metric_for_interface(interface_alias: &str) -> Result<bool> {
-    let interface_alias_ws =
-        WideCString::from_str(interface_alias).chain_err(|| ErrorKind::InvalidInterfaceAlias)?;
-    unsafe {
-        WinRoute_EnsureTopMetric(
-            interface_alias_ws.as_wide_c_str().as_ptr(),
-            Some(ffi::error_sink),
-            ptr::null_mut(),
-        ).into()
-    }
-}
-
-// Allowing dead code here as this type should only ever be constructed by an
-// FFI function.
-#[allow(dead_code)]
-#[repr(u32)]
-enum MetricResult {
-    MetricsUnchanged = 0u32,
-    MetricsChanged = 1u32,
-    Failure = 2u32,
-    UnexpectedValue,
-}
-
-impl Into<Result<bool>> for MetricResult {
-    fn into(self) -> Result<bool> {
-        match self {
-            MetricResult::MetricsUnchanged => Ok(false),
-            MetricResult::MetricsChanged => Ok(true),
-            MetricResult::Failure => Err(Error::from(ErrorKind::MetricApplication)),
-            MetricResult::UnexpectedValue => {
-                error!("Unexpected return code from WinRoute_EnsureTopMetric");
-                Err(Error::from(ErrorKind::MetricApplication))
-            }
-        }
-    }
-}
-
-extern "system" {
-    #[link_name(WinRoute_EnsureTopMetric)]
-    fn WinRoute_EnsureTopMetric(
-        tunnel_interface_alias: *const libc::wchar_t,
-        sink: Option<ffi::ErrorSink>,
-        sink_context: *mut libc::c_void,
-    ) -> MetricResult;
-}
diff --git a/talpid-core/src/tunnel/mod.rs b/talpid-core/src/tunnel/mod.rs
index 59f032b286..36b3ff654b 100644
--- a/talpid-core/src/tunnel/mod.rs
+++ b/talpid-core/src/tunnel/mod.rs
@@ -322,13 +322,26 @@ fn is_ipv6_enabled_in_os() -> bool {
         use winreg::enums::*;
         use winreg::RegKey;
 
-        const IPV6_DISABLED: u8 = 0xFF;
+        const IPV6_DISABLED_ON_TUNNELS_MASK: u32 = 0x01;
 
-        RegKey::predef(HKEY_LOCAL_MACHINE)
+        // Check registry if IPv6 is disabled on tunnel interfaces, as documented in
+        // https://support.microsoft.com/en-us/help/929852/guidance-for-configuring-ipv6-in-windows-for-advanced-users
+        let globally_enabled = RegKey::predef(HKEY_LOCAL_MACHINE)
             .open_subkey(r#"SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters"#)
             .and_then(|ipv6_config| ipv6_config.get_value("DisabledComponents"))
-            .map(|ipv6_disabled_bits: u32| (ipv6_disabled_bits & 0xFF) == IPV6_DISABLED as u32)
-            .unwrap_or(false)
+            .map(|ipv6_disabled_bits: u32| {
+                (ipv6_disabled_bits & IPV6_DISABLED_ON_TUNNELS_MASK) == 0
+            }).unwrap_or(true);
+        let enabled_on_tap = ::winnet::get_tap_interface_ipv6_status().unwrap_or(false);
+
+        if !globally_enabled {
+            debug!("IPv6 disabled in tunnel interfaces");
+        }
+        if !enabled_on_tap {
+            debug!("IPv6 disabled in TAP adapter");
+        }
+
+        globally_enabled && enabled_on_tap
     }
     #[cfg(target_os = "linux")]
     {
diff --git a/talpid-core/src/winnet.rs b/talpid-core/src/winnet.rs
new file mode 100644
index 0000000000..ef3930649c
--- /dev/null
+++ b/talpid-core/src/winnet.rs
@@ -0,0 +1,92 @@
+use std::ptr;
+
+use libc::{c_char, c_void, wchar_t};
+use widestring::WideCString;
+
+error_chain!{
+    errors{
+        /// Failure to set metrics of network interfaces
+        MetricApplication{
+            description("Failed to set the metrics for a network interface")
+        }
+        InvalidInterfaceAlias{
+            description("Supplied interface alias is invalid")
+        }
+        GetIpv6Status {
+            description("Failed to read IPv6 status on the TAP network interface")
+        }
+    }
+}
+
+pub type ErrorSink = extern "system" fn(msg: *const c_char, ctx: *mut c_void);
+
+pub extern "system" fn error_sink(msg: *const c_char, _ctx: *mut c_void) {
+    use std::ffi::CStr;
+    if msg.is_null() {
+        error!("Log message from FFI boundary is NULL");
+    } else {
+        error!("{}", unsafe { CStr::from_ptr(msg).to_string_lossy() });
+    }
+}
+
+/// Returns true if metrics were changed, false otherwise
+pub fn ensure_top_metric_for_interface(interface_alias: &str) -> Result<bool> {
+    let interface_alias_ws =
+        WideCString::from_str(interface_alias).chain_err(|| ErrorKind::InvalidInterfaceAlias)?;
+
+    let metric_result = unsafe {
+        WinRoute_EnsureTopMetric(
+            interface_alias_ws.as_wide_c_str().as_ptr(),
+            Some(error_sink),
+            ptr::null_mut(),
+        )
+    };
+
+    match metric_result {
+        // Metrics didn't change
+        0 => Ok(false),
+        // Metrics changed
+        1 => Ok(true),
+        // Failure
+        2 => Err(Error::from(ErrorKind::MetricApplication)),
+        // Unexpected value
+        _ => {
+            error!("Unexpected return code from WinRoute_EnsureTopMetric");
+            Err(Error::from(ErrorKind::MetricApplication))
+        }
+    }
+}
+
+extern "system" {
+    #[link_name(WinRoute_EnsureTopMetric)]
+    fn WinRoute_EnsureTopMetric(
+        tunnel_interface_alias: *const wchar_t,
+        sink: Option<ErrorSink>,
+        sink_context: *mut c_void,
+    ) -> u32;
+}
+
+
+/// Checks if IPv6 is enabled for the TAP interface
+pub fn get_tap_interface_ipv6_status() -> Result<bool> {
+    let tap_ipv6_status = unsafe { GetTapInterfaceIpv6Status(Some(error_sink), ptr::null_mut()) };
+
+    match tap_ipv6_status {
+        // Enabled
+        0 => Ok(true),
+        // Disabled
+        1 => Ok(false),
+        // Failure
+        2 => Err(Error::from(ErrorKind::GetIpv6Status)),
+        // Unexpected value
+        _ => {
+            error!("Unexpected return code from GetTapInterfaceIpv6Status");
+            Err(Error::from(ErrorKind::GetIpv6Status))
+        }
+    }
+}
+
+extern "system" {
+    #[link_name(GetTapInterfaceIpv6Status)]
+    fn GetTapInterfaceIpv6Status(sink: Option<ErrorSink>, sink_context: *mut c_void) -> u32;
+}
diff --git a/windows/winroute/extras.sln b/windows/winroute/extras.sln
new file mode 100644
index 0000000000..28d1d51341
--- /dev/null
+++ b/windows/winroute/extras.sln
@@ -0,0 +1,57 @@
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 15
+VisualStudioVersion = 15.0.27130.2027
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "loader", "src\extras\loader\loader.vcxproj", "{227C50F4-D9F6-4D9A-84A0-33CE84432D0D}"
+	ProjectSection(ProjectDependencies) = postProject
+		{B52E2D10-A94A-4605-914A-2DCEF6A757EF} = {B52E2D10-A94A-4605-914A-2DCEF6A757EF}
+		{89C5CDE8-04DB-4D9C-A8D8-7F786DAFB6D4} = {89C5CDE8-04DB-4D9C-A8D8-7F786DAFB6D4}
+	EndProjectSection
+EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "winroute", "src\winroute\winroute.vcxproj", "{89C5CDE8-04DB-4D9C-A8D8-7F786DAFB6D4}"
+	ProjectSection(ProjectDependencies) = postProject
+		{B52E2D10-A94A-4605-914A-2DCEF6A757EF} = {B52E2D10-A94A-4605-914A-2DCEF6A757EF}
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+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|x64 = Debug|x64
+		Debug|x86 = Debug|x86
+		Release|x64 = Release|x64
+		Release|x86 = Release|x86
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
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+		{89C5CDE8-04DB-4D9C-A8D8-7F786DAFB6D4}.Debug|x86.ActiveCfg = Debug|Win32
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+		{89C5CDE8-04DB-4D9C-A8D8-7F786DAFB6D4}.Release|x64.ActiveCfg = Release|x64
+		{89C5CDE8-04DB-4D9C-A8D8-7F786DAFB6D4}.Release|x64.Build.0 = Release|x64
+		{89C5CDE8-04DB-4D9C-A8D8-7F786DAFB6D4}.Release|x86.ActiveCfg = Release|Win32
+		{89C5CDE8-04DB-4D9C-A8D8-7F786DAFB6D4}.Release|x86.Build.0 = Release|Win32
+		{B52E2D10-A94A-4605-914A-2DCEF6A757EF}.Debug|x64.ActiveCfg = Debug|x64
+		{B52E2D10-A94A-4605-914A-2DCEF6A757EF}.Debug|x64.Build.0 = Debug|x64
+		{B52E2D10-A94A-4605-914A-2DCEF6A757EF}.Debug|x86.ActiveCfg = Debug|Win32
+		{B52E2D10-A94A-4605-914A-2DCEF6A757EF}.Debug|x86.Build.0 = Debug|Win32
+		{B52E2D10-A94A-4605-914A-2DCEF6A757EF}.Release|x64.ActiveCfg = Release|x64
+		{B52E2D10-A94A-4605-914A-2DCEF6A757EF}.Release|x64.Build.0 = Release|x64
+		{B52E2D10-A94A-4605-914A-2DCEF6A757EF}.Release|x86.ActiveCfg = Release|Win32
+		{B52E2D10-A94A-4605-914A-2DCEF6A757EF}.Release|x86.Build.0 = Release|Win32
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {B11B65B3-3DA6-495C-B0F5-5ACBB2F1743D}
+	EndGlobalSection
+EndGlobal
diff --git a/windows/winroute/src/extras/loader/loader.cpp b/windows/winroute/src/extras/loader/loader.cpp
new file mode 100644
index 0000000000..cb775538f9
--- /dev/null
+++ b/windows/winroute/src/extras/loader/loader.cpp
@@ -0,0 +1,10 @@
+#include "stdafx.h"
+#include "../../winroute/winroute.h"
+
+int main()
+{
+	const auto status = GetTapInterfaceIpv6Status(nullptr, nullptr);
+
+    return 0;
+}
+
diff --git a/windows/winroute/src/extras/loader/loader.vcxproj b/windows/winroute/src/extras/loader/loader.vcxproj
new file mode 100644
index 0000000000..bf010c1fd0
--- /dev/null
+++ b/windows/winroute/src/extras/loader/loader.vcxproj
@@ -0,0 +1,176 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
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+    <ProjectConfiguration Include="Debug|Win32">
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+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
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+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
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+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="loader.cpp" />
+    <ClCompile Include="stdafx.cpp" />
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="stdafx.h" />
+    <ClInclude Include="targetver.h" />
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+    <VCProjectVersion>15.0</VCProjectVersion>
+    <ProjectGuid>{227C50F4-D9F6-4D9A-84A0-33CE84432D0D}</ProjectGuid>
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+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+    <IntDir>$(SolutionDir)bin\temp\$(Platform)-$(Configuration)\$(ProjectName)\</IntDir>
+    <OutDir>$(SolutionDir)bin\$(Platform)-$(Configuration)\</OutDir>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <LinkIncremental>true</LinkIncremental>
+    <IntDir>$(SolutionDir)bin\temp\$(Platform)-$(Configuration)\$(ProjectName)\</IntDir>
+    <OutDir>$(SolutionDir)bin\$(Platform)-$(Configuration)\</OutDir>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <IntDir>$(SolutionDir)bin\temp\$(Platform)-$(Configuration)\$(ProjectName)\</IntDir>
+    <OutDir>$(SolutionDir)bin\$(Platform)-$(Configuration)\</OutDir>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <LinkIncremental>false</LinkIncremental>
+    <IntDir>$(SolutionDir)bin\temp\$(Platform)-$(Configuration)\$(ProjectName)\</IntDir>
+    <OutDir>$(SolutionDir)bin\$(Platform)-$(Configuration)\</OutDir>
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>Create</PrecompiledHeader>
+      <WarningLevel>Level4</WarningLevel>
+      <Optimization>Disabled</Optimization>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalLibraryDirectories>$(SolutionDir)/bin/$(Platform)-$(Configuration)</AdditionalLibraryDirectories>
+      <AdditionalDependencies>winroute.lib;kernel32.lib;user32.lib;gdi32.lib;winspool.lib;comdlg32.lib;advapi32.lib;shell32.lib;ole32.lib;oleaut32.lib;uuid.lib;odbc32.lib;odbccp32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <ClCompile>
+      <PrecompiledHeader>Create</PrecompiledHeader>
+      <WarningLevel>Level4</WarningLevel>
+      <Optimization>Disabled</Optimization>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalLibraryDirectories>$(SolutionDir)/bin/$(Platform)-$(Configuration)</AdditionalLibraryDirectories>
+      <AdditionalDependencies>winroute.lib;kernel32.lib;user32.lib;gdi32.lib;winspool.lib;comdlg32.lib;advapi32.lib;shell32.lib;ole32.lib;oleaut32.lib;uuid.lib;odbc32.lib;odbccp32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>Create</PrecompiledHeader>
+      <WarningLevel>Level4</WarningLevel>
+      <Optimization>MaxSpeed</Optimization>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalLibraryDirectories>$(SolutionDir)/bin/$(Platform)-$(Configuration)</AdditionalLibraryDirectories>
+      <AdditionalDependencies>winroute.lib;kernel32.lib;user32.lib;gdi32.lib;winspool.lib;comdlg32.lib;advapi32.lib;shell32.lib;ole32.lib;oleaut32.lib;uuid.lib;odbc32.lib;odbccp32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <ClCompile>
+      <PrecompiledHeader>Create</PrecompiledHeader>
+      <WarningLevel>Level4</WarningLevel>
+      <Optimization>MaxSpeed</Optimization>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalLibraryDirectories>$(SolutionDir)/bin/$(Platform)-$(Configuration)</AdditionalLibraryDirectories>
+      <AdditionalDependencies>winroute.lib;kernel32.lib;user32.lib;gdi32.lib;winspool.lib;comdlg32.lib;advapi32.lib;shell32.lib;ole32.lib;oleaut32.lib;uuid.lib;odbc32.lib;odbccp32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+    </Link>
+  </ItemDefinitionGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
\ No newline at end of file
diff --git a/windows/winroute/src/extras/loader/loader.vcxproj.filters b/windows/winroute/src/extras/loader/loader.vcxproj.filters
new file mode 100644
index 0000000000..cd0f4643c7
--- /dev/null
+++ b/windows/winroute/src/extras/loader/loader.vcxproj.filters
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <ClCompile Include="loader.cpp" />
+    <ClCompile Include="stdafx.cpp" />
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="stdafx.h" />
+    <ClInclude Include="targetver.h" />
+  </ItemGroup>
+</Project>
\ No newline at end of file
diff --git a/windows/winroute/src/extras/loader/stdafx.cpp b/windows/winroute/src/extras/loader/stdafx.cpp
new file mode 100644
index 0000000000..8d6fa45555
--- /dev/null
+++ b/windows/winroute/src/extras/loader/stdafx.cpp
@@ -0,0 +1,8 @@
+// stdafx.cpp : source file that includes just the standard includes
+// loader.pch will be the pre-compiled header
+// stdafx.obj will contain the pre-compiled type information
+
+#include "stdafx.h"
+
+// TODO: reference any additional headers you need in STDAFX.H
+// and not in this file
diff --git a/windows/winroute/src/extras/loader/stdafx.h b/windows/winroute/src/extras/loader/stdafx.h
new file mode 100644
index 0000000000..b005a839de
--- /dev/null
+++ b/windows/winroute/src/extras/loader/stdafx.h
@@ -0,0 +1,15 @@
+// stdafx.h : include file for standard system include files,
+// or project specific include files that are used frequently, but
+// are changed infrequently
+//
+
+#pragma once
+
+#include "targetver.h"
+
+#include <stdio.h>
+#include <tchar.h>
+
+
+
+// TODO: reference additional headers your program requires here
diff --git a/windows/winroute/src/extras/loader/targetver.h b/windows/winroute/src/extras/loader/targetver.h
new file mode 100644
index 0000000000..87c0086de7
--- /dev/null
+++ b/windows/winroute/src/extras/loader/targetver.h
@@ -0,0 +1,8 @@
+#pragma once
+
+// Including SDKDDKVer.h defines the highest available Windows platform.
+
+// If you wish to build your application for a previous Windows platform, include WinSDKVer.h and
+// set the _WIN32_WINNT macro to the platform you wish to support before including SDKDDKVer.h.
+
+#include <SDKDDKVer.h>
diff --git a/windows/winroute/src/winroute/InterfacePair.h b/windows/winroute/src/winroute/InterfacePair.h
index 3926ba0430..9582bac3cd 100644
--- a/windows/winroute/src/winroute/InterfacePair.h
+++ b/windows/winroute/src/winroute/InterfacePair.h
@@ -14,8 +14,8 @@ public:
 
 
 private:
-	MIB_IPINTERFACE_ROW IPv4Iface;
-	MIB_IPINTERFACE_ROW IPv6Iface;
+	MIB_IPINTERFACE_ROW IPv4Iface = { 0 };
+	MIB_IPINTERFACE_ROW IPv6Iface = { 0 };
 
 	void InitializeInterface(PMIB_IPINTERFACE_ROW iface);
 	bool HasIPv4();
diff --git a/windows/winroute/src/winroute/NetworkInterfaces.cpp b/windows/winroute/src/winroute/NetworkInterfaces.cpp
index a0a4d53db8..2aa352de27 100644
--- a/windows/winroute/src/winroute/NetworkInterfaces.cpp
+++ b/windows/winroute/src/winroute/NetworkInterfaces.cpp
@@ -74,19 +74,7 @@ NetworkInterfaces::NetworkInterfaces()
 
 bool NetworkInterfaces::SetTopMetricForInterfacesByAlias(const wchar_t * deviceAlias)
 {
-	NET_LUID targetIfaceLuid;
-	DWORD success = 0;
-	success = ConvertInterfaceAliasToLuid(deviceAlias, &targetIfaceLuid);
-	if (success != NO_ERROR)
-	{
-		std::wstringstream ss;
-		ss << L"Failed to convert interface alias '"
-			<< deviceAlias
-			<< "' into LUID: "
-			<< success;
-		throw std::runtime_error(common::string::ToAnsi(ss.str()));
-	}
-	return SetTopMetricForInterfacesWithLuid(targetIfaceLuid);
+	return SetTopMetricForInterfacesWithLuid(GetInterfaceLuid(deviceAlias));
 }
 
 bool NetworkInterfaces::SetTopMetricForInterfacesWithLuid(NET_LUID targetIfaceId)
@@ -107,3 +95,41 @@ NetworkInterfaces::~NetworkInterfaces()
 {
 	FreeMibTable(mInterfaces);
 }
+
+//static
+NET_LUID NetworkInterfaces::GetInterfaceLuid(const std::wstring &interfaceAlias)
+{
+	NET_LUID interfaceLuid;
+
+	const auto status = ConvertInterfaceAliasToLuid(interfaceAlias.c_str(), &interfaceLuid);
+
+	if (status != NO_ERROR)
+	{
+		std::wstringstream ss;
+
+		ss << L"Failed to convert interface alias '"
+			<< interfaceAlias
+			<< "' into LUID. Error: "
+			<< status;
+
+		throw std::runtime_error(common::string::ToAnsi(ss.str()));
+	}
+
+	return interfaceLuid;
+}
+
+const MIB_IPINTERFACE_ROW *NetworkInterfaces::GetInterface(NET_LUID interfaceLuid, ADDRESS_FAMILY interfaceFamily)
+{
+	for (unsigned int i = 0; i < mInterfaces->NumEntries; ++i)
+	{
+		MIB_IPINTERFACE_ROW &candidateInterface = mInterfaces->Table[i];
+
+		if (candidateInterface.InterfaceLuid.Value == interfaceLuid.Value
+			&& candidateInterface.Family == interfaceFamily)
+		{
+			return &candidateInterface;
+		}
+	}
+
+	return nullptr;
+}
diff --git a/windows/winroute/src/winroute/NetworkInterfaces.h b/windows/winroute/src/winroute/NetworkInterfaces.h
index b29ce0fa44..bf1d53dddf 100644
--- a/windows/winroute/src/winroute/NetworkInterfaces.h
+++ b/windows/winroute/src/winroute/NetworkInterfaces.h
@@ -6,6 +6,7 @@
 #include <iphlpapi.h>
 #include <netioapi.h>
 #include <cstdint>
+#include <string>
 
 class NetworkInterfaces
 {
@@ -15,11 +16,17 @@ private:
 	bool HasHighestMetric(PMIB_IPINTERFACE_ROW targetIface);
 
 public:
+	NetworkInterfaces(const NetworkInterfaces &) = delete;
+	NetworkInterfaces &operator=(const NetworkInterfaces &) = delete;
+
 	void EnsureIfaceMetricIsHighest(NET_LUID interfaceLuid);
 	NetworkInterfaces();
 	bool SetTopMetricForInterfacesByAlias(const wchar_t *deviceAlias);
 	bool SetTopMetricForInterfacesWithLuid(NET_LUID targetIface);
 	~NetworkInterfaces();
+
+	static NET_LUID GetInterfaceLuid(const std::wstring &interfaceAlias);
+	const MIB_IPINTERFACE_ROW *GetInterface(NET_LUID interfaceLuid, ADDRESS_FAMILY interfaceFamily);
 };
 
 const static uint32_t MAX_METRIC = 1;
diff --git a/windows/winroute/src/winroute/winroute.cpp b/windows/winroute/src/winroute/winroute.cpp
index c417bd44ea..b9f10e3786 100644
--- a/windows/winroute/src/winroute/winroute.cpp
+++ b/windows/winroute/src/winroute/winroute.cpp
@@ -1,6 +1,7 @@
 #include "stdafx.h"

 #include "winroute.h"

 #include "NetworkInterfaces.h"

+#include "libcommon/error.h"

 #include <cstdint>

 #include <stdexcept>

 

@@ -35,3 +36,47 @@ WinRoute_EnsureTopMetric(
 	}

 };

 

+extern "C"

+WINROUTE_LINKAGE

+TAP_IPV6_STATUS

+WINROUTE_API

+GetTapInterfaceIpv6Status(

+	WinRouteErrorSink errorSink,

+	void* errorSinkContext

+)

+{

+	try

+	{

+		MIB_IPINTERFACE_ROW interface = { 0 };

+

+		interface.InterfaceLuid = NetworkInterfaces::GetInterfaceLuid(L"Mullvad");

+		interface.Family = AF_INET6;

+

+		const auto status = GetIpInterfaceEntry(&interface);

+

+		if (NO_ERROR == status)

+		{

+			return TAP_IPV6_STATUS::ENABLED;

+		}

+

+		if (ERROR_NOT_FOUND == status)

+		{

+			return TAP_IPV6_STATUS::DISABLED;

+		}

+

+		common::error::Throw("Resolve TAP IPv6 interface", status);

+	}

+	catch (std::exception &err)

+	{

+		if (nullptr != errorSink)

+		{

+			errorSink(err.what(), errorSinkContext);

+		}

+

+		return TAP_IPV6_STATUS::FAILURE;

+	}

+	catch (...)

+	{

+		return TAP_IPV6_STATUS::FAILURE;

+	}

+}

diff --git a/windows/winroute/src/winroute/winroute.def b/windows/winroute/src/winroute/winroute.def
index d409889c50..2ea9222482 100644
--- a/windows/winroute/src/winroute/winroute.def
+++ b/windows/winroute/src/winroute/winroute.def
@@ -1,3 +1,4 @@
 LIBRARY winroute
 EXPORTS
-	WinRoute_EnsureTopMetric
\ No newline at end of file
+	WinRoute_EnsureTopMetric
+	GetTapInterfaceIpv6Status
diff --git a/windows/winroute/src/winroute/winroute.h b/windows/winroute/src/winroute/winroute.h
index 6bf0c3b882..6b500cee7e 100644
--- a/windows/winroute/src/winroute/winroute.h
+++ b/windows/winroute/src/winroute/winroute.h
@@ -28,3 +28,23 @@ WinRoute_EnsureTopMetric(
 	WinRouteErrorSink errorSink,
 	void* errorSinkContext
 );
+
+enum class TAP_IPV6_STATUS : uint32_t
+{
+	ENABLED = 0,
+	DISABLED = 1,
+	FAILURE = 2,
+};
+
+//
+// This has nothing to do with routing.
+// We should probably rename this module and use it to gather one-off network functions.
+//
+extern "C"
+WINROUTE_LINKAGE
+TAP_IPV6_STATUS
+WINROUTE_API
+GetTapInterfaceIpv6Status(
+	WinRouteErrorSink errorSink,
+	void* errorSinkContext
+);