Add testcase and fix for ASIO ipv4 localhost support (#649)

- Bugfix: Implement two listening sockets in ASIO (ipv4+ipv6) when either we start with `--http-forceloopback` or we resort to that mode because of a failure to bind to the "any" address

1 files changed, 59 insertions, 14 deletions

diff --git a/src/zenhttp/servers/httpasio.cpp b/src/zenhttp/servers/httpasio.cpp
index 9fca314b3..6b45c259d 100644
--- a/src/zenhttp/servers/httpasio.cpp
+++ b/src/zenhttp/servers/httpasio.cpp
@@ -573,29 +573,42 @@ struct HttpAcceptor
 	: m_Server(Server)
 	, m_IoService(IoService)
 	, m_Acceptor(m_IoService, asio::ip::tcp::v6())
+	, m_AlternateProtocolAcceptor(m_IoService, asio::ip::tcp::v4())
 	{
 		m_Acceptor.set_option(asio::ip::v6_only(false));
 #if ZEN_PLATFORM_WINDOWS
 		// Special option for Windows settings as !asio::socket_base::reuse_address is not the same as exclusive access on Windows platforms
-		typedef asio::detail::socket_option::boolean<ASIO_OS_DEF(SOL_SOCKET), SO_EXCLUSIVEADDRUSE> excluse_address;
-		m_Acceptor.set_option(excluse_address(true));
+		typedef asio::detail::socket_option::boolean<ASIO_OS_DEF(SOL_SOCKET), SO_EXCLUSIVEADDRUSE> exclusive_address;
+		m_Acceptor.set_option(exclusive_address(true));
+		m_AlternateProtocolAcceptor.set_option(exclusive_address(true));
 #else	// ZEN_PLATFORM_WINDOWS
 		m_Acceptor.set_option(asio::socket_base::reuse_address(false));
+		m_AlternateProtocolAcceptor.set_option(asio::socket_base::reuse_address(false));
 #endif	// ZEN_PLATFORM_WINDOWS
 
 		m_Acceptor.set_option(asio::ip::tcp::no_delay(true));
 		m_Acceptor.set_option(asio::socket_base::receive_buffer_size(128 * 1024));
 		m_Acceptor.set_option(asio::socket_base::send_buffer_size(256 * 1024));
 
+		m_AlternateProtocolAcceptor.set_option(asio::ip::tcp::no_delay(true));
+		m_AlternateProtocolAcceptor.set_option(asio::socket_base::receive_buffer_size(128 * 1024));
+		m_AlternateProtocolAcceptor.set_option(asio::socket_base::send_buffer_size(256 * 1024));
+
 		asio::ip::address_v6 BindAddress   = ForceLoopback ? asio::ip::address_v6::loopback() : asio::ip::address_v6::any();
 		uint16_t			 EffectivePort = BasePort;
 
+		if (BindAddress.is_loopback())
+		{
+			m_Acceptor.set_option(asio::ip::v6_only(true));
+		}
+
 		asio::error_code BindErrorCode;
 		m_Acceptor.bind(asio::ip::tcp::endpoint(BindAddress, EffectivePort), BindErrorCode);
 		if (BindErrorCode == asio::error::access_denied && !BindAddress.is_loopback())
 		{
 			// Access denied for a public port - lets try fall back to local port only
 			BindAddress = asio::ip::address_v6::loopback();
+			m_Acceptor.set_option(asio::ip::v6_only(true));
 			m_Acceptor.bind(asio::ip::tcp::endpoint(BindAddress, EffectivePort), BindErrorCode);
 		}
 		// Sharing violation implies the port is being used by another process
@@ -615,6 +628,8 @@ struct HttpAcceptor
 		}
 		else if (BindAddress.is_loopback())
 		{
+			m_AlternateProtocolAcceptor.bind(asio::ip::tcp::endpoint(asio::ip::address_v4::loopback(), EffectivePort), BindErrorCode);
+			m_UseAlternateProtocolAcceptor = true;
 			ZEN_INFO("Registered local-only handler 'http://{}:{}/' - this is not accessible from remote hosts", "[::1]", EffectivePort);
 		}
 
@@ -635,8 +650,25 @@ struct HttpAcceptor
 				 &OptionNumberOfBytesReturned,
 				 0,
 				 0);
+		if (m_UseAlternateProtocolAcceptor)
+		{
+			NativeSocket = m_AlternateProtocolAcceptor.native_handle();
+			WSAIoctl(NativeSocket,
+					 SIO_LOOPBACK_FAST_PATH,
+					 &LoopbackOptionValue,
+					 sizeof(LoopbackOptionValue),
+					 NULL,
+					 0,
+					 &OptionNumberOfBytesReturned,
+					 0,
+					 0);
+		}
 #endif
 		m_Acceptor.listen();
+		if (m_UseAlternateProtocolAcceptor)
+		{
+			m_AlternateProtocolAcceptor.listen();
+		}
 
 		ZEN_INFO("Started asio server at 'http://{}:{}'", BindAddress.is_loopback() ? "[::1]" : "*", EffectivePort);
 	}
@@ -644,22 +676,30 @@ struct HttpAcceptor
 	void Start()
 	{
 		m_Acceptor.listen();
-		InitAccept();
+		InitAcceptInternal(m_Acceptor);
+		if (m_UseAlternateProtocolAcceptor)
+		{
+			m_AlternateProtocolAcceptor.listen();
+			InitAcceptInternal(m_AlternateProtocolAcceptor);
+		}
 	}
 
 	void Stop() { m_IsStopped = true; }
 
-	void InitAccept()
+	int GetAcceptPort() { return m_Acceptor.local_endpoint().port(); }
+
+private:
+	void InitAcceptInternal(asio::ip::tcp::acceptor& Acceptor)
 	{
 		auto				   SocketPtr = std::make_unique<asio::ip::tcp::socket>(m_IoService);
 		asio::ip::tcp::socket& SocketRef = *SocketPtr.get();
 
-		m_Acceptor.async_accept(SocketRef, [this, Socket = std::move(SocketPtr)](const asio::error_code& Ec) mutable {
+		Acceptor.async_accept(SocketRef, [this, &Acceptor, Socket = std::move(SocketPtr)](const asio::error_code& Ec) mutable {
 			if (Ec)
 			{
 				ZEN_WARN("asio async_accept, connection failed to '{}:{}' reason '{}'",
-						 m_Acceptor.local_endpoint().address().to_string(),
-						 m_Acceptor.local_endpoint().port(),
+						 Acceptor.local_endpoint().address().to_string(),
+						 Acceptor.local_endpoint().port(),
 						 Ec.message());
 			}
 			else
@@ -679,12 +719,12 @@ struct HttpAcceptor
 
 			if (!m_IsStopped.load())
 			{
-				InitAccept();
+				InitAcceptInternal(Acceptor);
 			}
 			else
 			{
 				std::error_code CloseEc;
-				m_Acceptor.close(CloseEc);
+				Acceptor.close(CloseEc);
 				if (CloseEc)
 				{
 					ZEN_WARN("acceptor close ERROR, reason '{}'", CloseEc.message());
@@ -693,12 +733,11 @@ struct HttpAcceptor
 		});
 	}
 
-	int GetAcceptPort() { return m_Acceptor.local_endpoint().port(); }
-
-private:
 	HttpAsioServerImpl&		m_Server;
 	asio::io_service&		m_IoService;
 	asio::ip::tcp::acceptor m_Acceptor;
+	asio::ip::tcp::acceptor m_AlternateProtocolAcceptor;
+	bool					m_UseAlternateProtocolAcceptor{false};
 	std::atomic<bool>		m_IsStopped{false};
 };
 
@@ -884,11 +923,17 @@ HttpAsioServerImpl::Start(uint16_t Port, bool ForceLooopback, int ThreadCount)
 void
 HttpAsioServerImpl::Stop()
 {
-	m_Acceptor->Stop();
+	if (m_Acceptor)
+	{
+		m_Acceptor->Stop();
+	}
 	m_IoService.stop();
 	for (auto& Thread : m_ThreadPool)
 	{
-		Thread.join();
+		if (Thread.joinable())
+		{
+			Thread.join();
+		}
 	}
 }