Add function to fuzzily determine TAP alias

7 files changed, 260 insertions, 0 deletions

diff --git a/windows/winroute/src/winroute/interfaceutils.cpp b/windows/winroute/src/winroute/interfaceutils.cpp
new file mode 100644
index 0000000000..1f3b95d3d9
--- /dev/null
+++ b/windows/winroute/src/winroute/interfaceutils.cpp
@@ -0,0 +1,127 @@
+#include "stdafx.h"
+#include "interfaceutils.h"
+#include "libcommon/error.h"
+#include "libcommon/string.h"
+#include "libcommon/synchronization.h"
+#include <vector>
+#include <cstdint>
+#include <algorithm>
+#include <winsock2.h>
+#include <iphlpapi.h>
+#include <windows.h>
+
+//static
+std::wstring InterfaceUtils::m_alias;
+
+//static
+std::mutex InterfaceUtils::m_mutex;
+
+//static
+std::set<InterfaceUtils::NetworkAdapter> InterfaceUtils::GetAllAdapters()
+{
+	ULONG bufferSize = 0;
+
+	const ULONG flags = GAA_FLAG_SKIP_UNICAST | GAA_FLAG_SKIP_ANYCAST | GAA_FLAG_SKIP_MULTICAST | GAA_FLAG_SKIP_DNS_SERVER;
+
+	auto status = GetAdaptersAddresses(AF_INET, flags, nullptr, nullptr, &bufferSize);
+
+	THROW_UNLESS(ERROR_BUFFER_OVERFLOW, status, "Probe for adapter listing buffer size");
+
+	// Memory is cheap, this avoids a looping construct.
+	bufferSize *= 2;
+
+	std::vector<uint8_t> buffer(bufferSize);
+
+	status = GetAdaptersAddresses(AF_INET, flags, nullptr,
+		reinterpret_cast<PIP_ADAPTER_ADDRESSES>(&buffer[0]), &bufferSize);
+
+	THROW_UNLESS(ERROR_SUCCESS, status, "Retrieve adapter listing");
+
+	std::set<NetworkAdapter> adapters;
+
+	for (auto it = (PIP_ADAPTER_ADDRESSES)&buffer[0]; nullptr != it; it = it->Next)
+	{
+		adapters.emplace(NetworkAdapter(common::string::ToWide(it->AdapterName),
+			it->Description, it->FriendlyName));
+	}
+
+	return adapters;
+}
+
+//static
+std::set<InterfaceUtils::NetworkAdapter>
+InterfaceUtils::GetTapAdapters(const std::set<InterfaceUtils::NetworkAdapter> &adapters)
+{
+	std::set<NetworkAdapter> tapAdapters;
+
+	for (const auto &adapter : adapters)
+	{
+		static const wchar_t name[] = L"TAP-Windows Adapter V9";
+
+		//
+		// Compare partial name, because once you start having more TAP adapters
+		// they're named "TAP-Windows Adapter V9 #2" and so on.
+		//
+
+		if (0 == adapter.name.compare(0, _countof(name) - 1, name))
+		{
+			tapAdapters.insert(adapter);
+		}
+	}
+
+	return tapAdapters;
+}
+
+//static
+std::wstring InterfaceUtils::GetTapInterfaceAlias()
+{
+	common::sync::ScopeLock<> cacheLock(m_mutex);
+
+	if (false == m_alias.empty())
+	{
+		return m_alias;
+	}
+
+	//
+	// Look for TAP adapter with alias "Mullvad".
+	//
+
+	auto adapters = GetTapAdapters(GetAllAdapters());
+
+	auto findByAlias = [](const std::set<NetworkAdapter> &adapters, const std::wstring &alias)
+	{
+		const auto it = std::find_if(adapters.begin(), adapters.end(), [&alias](const NetworkAdapter &candidate)
+		{
+			return _wcsicmp(candidate.alias.c_str(), alias.c_str());
+		});
+
+		return it != adapters.end();
+	};
+
+	static const wchar_t baseAlias[] = L"Mullvad";
+
+	if (findByAlias(adapters, baseAlias))
+	{
+		return m_alias = baseAlias;
+	}
+
+	//
+	// Look for TAP adapter with alias "Mullvad-1", "Mullvad-2", etc.
+	//
+
+	for (auto i = 0; i < 10; ++i)
+	{
+		std::wstringstream ss;
+
+		ss << baseAlias << L"-" << i;
+
+		const auto alias = ss.str();
+
+		if (findByAlias(adapters, alias))
+		{
+			return m_alias = alias;
+		}
+	}
+
+	throw std::runtime_error("Unable to find TAP adapter");
+}
diff --git a/windows/winroute/src/winroute/interfaceutils.h b/windows/winroute/src/winroute/interfaceutils.h
new file mode 100644
index 0000000000..c016706ba5
--- /dev/null
+++ b/windows/winroute/src/winroute/interfaceutils.h
@@ -0,0 +1,39 @@
+#pragma once
+
+#include <string>
+#include <set>
+#include <mutex>
+
+class InterfaceUtils
+{
+	InterfaceUtils() = delete;
+
+	static std::wstring m_alias;
+	static std::mutex m_mutex;
+
+public:
+
+	struct NetworkAdapter
+	{
+		std::wstring guid;
+		std::wstring name;
+		std::wstring alias;
+
+		NetworkAdapter(std::wstring _guid, std::wstring _name, std::wstring _alias)
+			: guid(_guid)
+			, name(_name)
+			, alias(_alias)
+		{
+		}
+
+		bool operator<(const NetworkAdapter &rhs) const
+		{
+			return _wcsicmp(guid.c_str(), rhs.guid.c_str()) < 0;
+		}
+	};
+
+	static std::set<NetworkAdapter> GetAllAdapters();
+	static std::set<NetworkAdapter> GetTapAdapters(const std::set<NetworkAdapter> &adapters);
+
+	static std::wstring GetTapInterfaceAlias();
+};
diff --git a/windows/winroute/src/winroute/stdafx.h b/windows/winroute/src/winroute/stdafx.h
index 677e68a9fa..254cb49b0d 100644
--- a/windows/winroute/src/winroute/stdafx.h
+++ b/windows/winroute/src/winroute/stdafx.h
@@ -5,6 +5,9 @@
 

 #pragma once

 

+// wcscpy

+#define _CRT_SECURE_NO_WARNINGS 1

+

 #include "targetver.h"

 

 #define WIN32_LEAN_AND_MEAN             // Exclude rarely-used stuff from Windows headers

diff --git a/windows/winroute/src/winroute/winroute.cpp b/windows/winroute/src/winroute/winroute.cpp
index b9f10e3786..f50da8eb48 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 "interfaceutils.h"

 #include "libcommon/error.h"

 #include <cstdint>

 #include <stdexcept>

@@ -80,3 +81,56 @@ GetTapInterfaceIpv6Status(
 		return TAP_IPV6_STATUS::FAILURE;

 	}

 }

+

+extern "C"

+WINROUTE_LINKAGE

+TAP_GET_ALIAS_STATUS

+WINROUTE_API

+GetTapInterfaceAlias(

+	wchar_t **alias,

+	WinRouteErrorSink errorSink,

+	void* errorSinkContext

+)

+{

+	try

+	{

+		const auto currentAlias = InterfaceUtils::GetTapInterfaceAlias();

+

+		auto stringBuffer = new wchar_t[currentAlias.size() + 1];

+		wcscpy(stringBuffer, currentAlias.c_str());

+

+		*alias = stringBuffer;

+

+		return TAP_GET_ALIAS_STATUS::SUCCESS;

+	}

+	catch (std::exception &err)

+	{

+		if (nullptr != errorSink)

+		{

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

+		}

+

+		return TAP_GET_ALIAS_STATUS::GENERAL_ERROR;

+	}

+	catch (...)

+	{

+		return TAP_GET_ALIAS_STATUS::GENERAL_ERROR;

+	}

+}

+

+extern "C"

+WINROUTE_LINKAGE

+void

+WINROUTE_API

+ReleaseString(

+	wchar_t *str

+)

+{

+	try

+	{

+		delete[] str;

+	}

+	catch (...)

+	{

+	}

+}

diff --git a/windows/winroute/src/winroute/winroute.h b/windows/winroute/src/winroute/winroute.h
index 6b500cee7e..ac74c264c9 100644
--- a/windows/winroute/src/winroute/winroute.h
+++ b/windows/winroute/src/winroute/winroute.h
@@ -48,3 +48,36 @@ GetTapInterfaceIpv6Status(
 	WinRouteErrorSink errorSink,
 	void* errorSinkContext
 );
+
+enum class TAP_GET_ALIAS_STATUS : uint32_t
+{
+	GENERAL_ERROR = 0,
+	SUCCESS = 1,
+};
+
+
+//
+// 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_GET_ALIAS_STATUS
+WINROUTE_API
+GetTapInterfaceAlias(
+	wchar_t **alias,
+	WinRouteErrorSink errorSink,
+	void* errorSinkContext
+);
+
+//
+// As of now, this is a companion function to the above function.
+// Generically named in case we need other functions here that return strings.
+//
+extern "C"
+WINROUTE_LINKAGE
+void
+WINROUTE_API
+ReleaseString(
+	wchar_t *str
+);
diff --git a/windows/winroute/src/winroute/winroute.vcxproj b/windows/winroute/src/winroute/winroute.vcxproj
index 09efb76938..e168887331 100644
--- a/windows/winroute/src/winroute/winroute.vcxproj
+++ b/windows/winroute/src/winroute/winroute.vcxproj
@@ -21,12 +21,14 @@
   <ItemGroup>
     <ClCompile Include="dllmain.cpp" />
     <ClCompile Include="InterfacePair.cpp" />
+    <ClCompile Include="interfaceutils.cpp" />
     <ClCompile Include="NetworkInterfaces.cpp" />
     <ClCompile Include="stdafx.cpp" />
     <ClCompile Include="winroute.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="InterfacePair.h" />
+    <ClInclude Include="interfaceutils.h" />
     <ClInclude Include="NetworkInterfaces.h" />
     <ClInclude Include="stdafx.h" />
     <ClInclude Include="targetver.h" />
diff --git a/windows/winroute/src/winroute/winroute.vcxproj.filters b/windows/winroute/src/winroute/winroute.vcxproj.filters
index 216502d069..15b184cc7f 100644
--- a/windows/winroute/src/winroute/winroute.vcxproj.filters
+++ b/windows/winroute/src/winroute/winroute.vcxproj.filters
@@ -6,6 +6,7 @@
     <ClCompile Include="winroute.cpp" />
     <ClCompile Include="NetworkInterfaces.cpp" />
     <ClCompile Include="InterfacePair.cpp" />
+    <ClCompile Include="interfaceutils.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="stdafx.h" />
@@ -13,6 +14,7 @@
     <ClInclude Include="winroute.h" />
     <ClInclude Include="NetworkInterfaces.h" />
     <ClInclude Include="InterfacePair.h" />
+    <ClInclude Include="interfaceutils.h" />
   </ItemGroup>
   <ItemGroup>
     <None Include="winroute.def" />