From 68dc4e23d8b90a346cbd053c7cda37ba569725c8 Mon Sep 17 00:00:00 2001
From: Yihong Wu <54519668+domosekai@users.noreply.github.com>
Date: Wed, 15 Dec 2021 00:54:40 +0800
Subject: [PATCH] Improve NAT-T hint string handling

---
 src/Cedar/CM.c         | 14 +++++++++---
 src/Cedar/Client.c     | 50 ++++++++++++++++++++++++++++++++++++++++--
 src/Cedar/Command.c    | 36 +++++++++++++++++++++++++++---
 src/Cedar/Connection.h |  1 +
 src/Cedar/Protocol.c   | 18 ++++++++++-----
 src/Cedar/Protocol.h   |  2 ++
 src/Cedar/SM.c         | 42 +++++++++++++++++++++++++++++++++--
 src/Cedar/SMInner.h    |  2 +-
 src/Cedar/WinUi.c      |  7 +++++-
 src/Cedar/WinUi.h      |  2 ++
 src/Mayaqua/Network.c  | 46 ++++++++++----------------------------
 src/Mayaqua/Network.h  |  2 +-
 12 files changed, 170 insertions(+), 52 deletions(-)

diff --git a/src/Cedar/CM.c b/src/Cedar/CM.c
index 02df5267..4ca4cc37 100644
--- a/src/Cedar/CM.c
+++ b/src/Cedar/CM.c
@@ -6649,6 +6649,7 @@ void CmEditAccountDlgUpdate(HWND hWnd, CM_ACCOUNT *a)
 	// Host name
 	GetTxtA(hWnd, E_HOSTNAME, a->ClientOption->Hostname, sizeof(a->ClientOption->Hostname));
 	Trim(a->ClientOption->Hostname);
+	a->ClientOption->HintStr[0] = 0;
 
 	if (InStr(a->ClientOption->Hostname, "/tcp"))
 	{
@@ -7091,10 +7092,17 @@ void CmEditAccountDlgInit(HWND hWnd, CM_ACCOUNT *a)
 	SetText(hWnd, E_ACCOUNT_NAME, a->ClientOption->AccountName);
 
 	// Host name
-	SetTextA(hWnd, E_HOSTNAME, a->ClientOption->Hostname);
-	StrCpy(a->old_server_name, sizeof(a->old_server_name), a->ClientOption->Hostname);
+	char hostname[MAX_SIZE];
+	StrCpy(hostname, sizeof(hostname), a->ClientOption->Hostname);
+	if (IsEmptyStr(a->ClientOption->HintStr) == false)
+	{
+		StrCat(hostname, sizeof(hostname), "/");
+		StrCat(hostname, sizeof(hostname), a->ClientOption->HintStr);
+	}
+	SetTextA(hWnd, E_HOSTNAME, hostname);
+	StrCpy(a->old_server_name, sizeof(a->old_server_name), hostname);
 
-	if (InStr(a->ClientOption->Hostname, "/tcp"))
+	if (InStr(hostname, "/tcp"))
 	{
 		Check(hWnd, R_DISABLE_NATT, true);
 	}
diff --git a/src/Cedar/Client.c b/src/Cedar/Client.c
index a45aff43..0d893f31 100644
--- a/src/Cedar/Client.c
+++ b/src/Cedar/Client.c
@@ -4315,6 +4315,13 @@ void InRpcClientOption(CLIENT_OPTION *c, PACK *p)
 
 	PackGetUniStr(p, "AccountName", c->AccountName, sizeof(c->AccountName));
 	PackGetStr(p, "Hostname", c->Hostname, sizeof(c->Hostname));
+	// Extract hint string from hostname
+	UINT i = SearchStrEx(c->Hostname, "/", 0, false);
+	if (i != INFINITE)
+	{
+		StrCpy(c->HintStr, sizeof(c->HintStr), c->Hostname + i + 1);
+		c->Hostname[i] = 0;
+	}
 	c->Port = PackGetInt(p, "Port");
 	c->PortUDP = PackGetInt(p, "PortUDP");
 	c->ProxyType = PackGetInt(p, "ProxyType");
@@ -4352,7 +4359,20 @@ void OutRpcClientOption(PACK *p, CLIENT_OPTION *c)
 	}
 
 	PackAddUniStr(p, "AccountName", c->AccountName);
-	PackAddStr(p, "Hostname", c->Hostname);
+	// Append hint string to hostname
+	if (IsEmptyStr(c->HintStr))
+	{
+		// No hint
+		PackAddStr(p, "Hostname", c->Hostname);
+	}
+	else
+	{
+		char hostname[MAX_SIZE];
+		StrCpy(hostname, sizeof(hostname), c->Hostname);
+		StrCat(hostname, sizeof(hostname), "/");
+		StrCat(hostname, sizeof(hostname), c->HintStr);
+		PackAddStr(p, "Hostname", hostname);
+	}
 	PackAddStr(p, "ProxyName", c->ProxyName);
 	PackAddStr(p, "ProxyUsername", c->ProxyUsername);
 	PackAddStr(p, "ProxyPassword", c->ProxyPassword);
@@ -7030,6 +7050,12 @@ bool CtEnumAccount(CLIENT *c, RPC_CLIENT_ENUM_ACCOUNT *e)
 
 			// Server name
 			StrCpy(item->ServerName, sizeof(item->ServerName), a->ClientOption->Hostname);
+			// Append hint string to hostname
+			if (IsEmptyStr(a->ClientOption->HintStr) == false)
+			{
+				StrCat(item->ServerName, sizeof(item->ServerName), "/");
+				StrCat(item->ServerName, sizeof(item->ServerName), a->ClientOption->HintStr);
+			}
 
 			// Proxy type
 			item->ProxyType = a->ClientOption->ProxyType;
@@ -9222,6 +9248,13 @@ CLIENT_OPTION *CiLoadClientOption(FOLDER *f)
 
 	CfgGetUniStr(f, "AccountName", o->AccountName, sizeof(o->AccountName));
 	CfgGetStr(f, "Hostname", o->Hostname, sizeof(o->Hostname));
+	// Extract hint string from hostname
+	UINT i = SearchStrEx(o->Hostname, "/", 0, false);
+	if (i != INFINITE)
+	{
+		StrCpy(o->HintStr, sizeof(o->HintStr), o->Hostname + i + 1);
+		o->Hostname[i] = 0;
+	}
 	o->Port = CfgGetInt(f, "Port");
 	o->PortUDP = CfgGetInt(f, "PortUDP");
 	o->ProxyType = CfgGetInt(f, "ProxyType");
@@ -9764,7 +9797,20 @@ void CiWriteClientOption(FOLDER *f, CLIENT_OPTION *o)
 	}
 
 	CfgAddUniStr(f, "AccountName", o->AccountName);
-	CfgAddStr(f, "Hostname", o->Hostname);
+	// Append hint string to hostname
+	if (IsEmptyStr(o->HintStr))
+	{
+		// No hint
+		CfgAddStr(f, "Hostname", o->Hostname);
+	}
+	else
+	{
+		char hostname[MAX_SIZE];
+		StrCpy(hostname, sizeof(hostname), o->Hostname);
+		StrCat(hostname, sizeof(hostname), "/");
+		StrCat(hostname, sizeof(hostname), o->HintStr);
+		CfgAddStr(f, "Hostname", hostname);
+	}
 	CfgAddInt(f, "Port", o->Port);
 	CfgAddInt(f, "PortUDP", o->PortUDP);
 	CfgAddInt(f, "ProxyType", o->ProxyType);
diff --git a/src/Cedar/Command.c b/src/Cedar/Command.c
index df188b6f..d9f885e1 100644
--- a/src/Cedar/Command.c
+++ b/src/Cedar/Command.c
@@ -4333,6 +4333,7 @@ UINT PcAccountSet(CONSOLE *c, char *cmd_name, wchar_t *str, void *param)
 		// Success
 		t.ClientOption->Port = port;
 		StrCpy(t.ClientOption->Hostname, sizeof(t.ClientOption->Hostname), host);
+		t.ClientOption->HintStr[0] = 0;
 		StrCpy(t.ClientOption->HubName, sizeof(t.ClientOption->HubName), GetParamStr(o, "HUB"));
 
 		Zero(&c, sizeof(c));
@@ -4400,7 +4401,18 @@ UINT PcAccountGet(CONSOLE *c, char *cmd_name, wchar_t *str, void *param)
 		CtInsert(ct, _UU("CMD_ACCOUNT_COLUMN_NAME"), t.ClientOption->AccountName);
 
 		// Host name of the destination VPN Server
-		StrToUni(tmp, sizeof(tmp), t.ClientOption->Hostname);
+		if (IsEmptyStr(t.ClientOption->HintStr))
+		{
+			StrToUni(tmp, sizeof(tmp), t.ClientOption->Hostname);
+		}
+		else
+		{
+			char hostname[MAX_SIZE];
+			StrCpy(hostname, sizeof(hostname), t.ClientOption->Hostname);
+			StrCat(hostname, sizeof(hostname), "/");
+			StrCat(hostname, sizeof(hostname), t.ClientOption->HintStr);
+			StrToUni(tmp, sizeof(tmp), hostname);
+		}
 		CtInsert(ct, _UU("CMD_ACCOUNT_COLUMN_HOSTNAME"), tmp);
 
 		// The port number to connect to VPN Server
@@ -13117,6 +13129,7 @@ UINT PsCascadeSet(CONSOLE *c, char *cmd_name, wchar_t *str, void *param)
 
 	t.ClientOption->Port = port;
 	StrCpy(t.ClientOption->Hostname, sizeof(t.ClientOption->Hostname), host);
+	t.ClientOption->HintStr[0] = 0;
 	StrCpy(t.ClientOption->HubName, sizeof(t.ClientOption->HubName), GetParamStr(o, "HUB"));
 
 	Free(host);
@@ -13223,7 +13236,18 @@ UINT PsCascadeGet(CONSOLE *c, char *cmd_name, wchar_t *str, void *param)
 		CtInsert(ct, _UU("CMD_ACCOUNT_COLUMN_NAME"), t.ClientOption->AccountName);
 
 		// Host name of the destination VPN Server
-		StrToUni(tmp, sizeof(tmp), t.ClientOption->Hostname);
+		if (IsEmptyStr(t.ClientOption->HintStr))
+		{
+			StrToUni(tmp, sizeof(tmp), t.ClientOption->Hostname);
+		}
+		else
+		{
+			char hostname[MAX_SIZE];
+			StrCpy(hostname, sizeof(hostname), t.ClientOption->Hostname);
+			StrCat(hostname, sizeof(hostname), "/");
+			StrCat(hostname, sizeof(hostname), t.ClientOption->HintStr);
+			StrToUni(tmp, sizeof(tmp), hostname);
+		}
 		CtInsert(ct, _UU("CMD_ACCOUNT_COLUMN_HOSTNAME"), tmp);
 
 		// The port number to connect to VPN Server
@@ -24273,6 +24297,12 @@ UINT PsConnect(CONSOLE *c, char *host, UINT port, char *hub, char *adminhub, wch
 	Zero(&o, sizeof(o));
 	UniStrCpy(o.AccountName, sizeof(o.AccountName), L"VPNCMD");
 	StrCpy(o.Hostname, sizeof(o.Hostname), host);
+	UINT i = SearchStrEx(o.Hostname, "/", 0, false);
+	if (i != INFINITE)
+	{
+		StrCpy(o.HintStr, sizeof(o.HintStr), o.Hostname + i + 1);
+		o.Hostname[i] = 0;
+	}
 	o.Port = port;
 	o.ProxyType = PROXY_DIRECT;
 
@@ -24331,7 +24361,7 @@ UINT PsConnect(CONSOLE *c, char *host, UINT port, char *hub, char *adminhub, wch
 			PS *ps;
 
 			// Success
-			ps = NewPs(c, rpc, host, port, hub, adminhub, cmdline);
+			ps = NewPs(c, rpc, o.Hostname, port, hub, adminhub, cmdline);
 			PsMain(ps);
 			retcode = ps->LastError;
 			FreePs(ps);
diff --git a/src/Cedar/Connection.h b/src/Cedar/Connection.h
index 9e82f98d..b7eff0a6 100644
--- a/src/Cedar/Connection.h
+++ b/src/Cedar/Connection.h
@@ -105,6 +105,7 @@ struct CLIENT_OPTION
 	char pad12[3];
 	UCHAR HostUniqueKey[SHA1_SIZE];							// Host unique key
 	char CustomHttpHeader[HTTP_CUSTOM_HEADER_MAX_SIZE];		// Custom HTTP proxy header
+	char HintStr[MAX_HOST_NAME_LEN + 1];					// Hint string for NAT-T
 };
 
 // Client authentication data
diff --git a/src/Cedar/Protocol.c b/src/Cedar/Protocol.c
index 94f2a682..1d058caa 100644
--- a/src/Cedar/Protocol.c
+++ b/src/Cedar/Protocol.c
@@ -6306,9 +6306,9 @@ SOCK *ClientConnectGetSocket(CONNECTION *c, bool additional_connect)
 		{
 			// If additional_connect == false, enable trying to NAT-T connection
 			// If additional_connect == true, follow the IsRUDPSession setting in this session
-			sock = TcpIpConnectEx(hostname, c->ServerPort,
+			sock = TcpIpConnectEx2(hostname, c->ServerPort,
 				(bool *)cancel_flag, c->hWndForUI, &nat_t_err, (additional_connect ? (!sess->IsRUDPSession) : false),
-				true, &resolved_ip);
+				true, o->HintStr, &resolved_ip);
 		}
 		else
 		{
@@ -6444,23 +6444,31 @@ UINT ProxyCodeToCedar(UINT code)
 
 // TCP connection function
 SOCK *TcpConnectEx3(char *hostname, UINT port, UINT timeout, bool *cancel_flag, void *hWnd, bool no_nat_t, UINT *nat_t_error_code, bool try_start_ssl, IP *ret_ip)
+{
+	return TcpConnectEx4(hostname, port, timeout, cancel_flag, hWnd, no_nat_t, nat_t_error_code, try_start_ssl, NULL, ret_ip);
+}
+SOCK *TcpConnectEx4(char *hostname, UINT port, UINT timeout, bool *cancel_flag, void *hWnd, bool no_nat_t, UINT *nat_t_error_code, bool try_start_ssl, char *hint_str, IP *ret_ip)
 {
 #ifdef	OS_WIN32
 	if (hWnd == NULL)
 	{
 #endif	// OS_WIN32
-		return ConnectEx4(hostname, port, timeout, cancel_flag, (no_nat_t ? NULL : VPN_RUDP_SVC_NAME), nat_t_error_code, try_start_ssl, true, ret_ip);
+		return ConnectEx5(hostname, port, timeout, cancel_flag, (no_nat_t ? NULL : VPN_RUDP_SVC_NAME), nat_t_error_code, try_start_ssl, true, hint_str, ret_ip);
 #ifdef	OS_WIN32
 	}
 	else
 	{
-		return WinConnectEx3((HWND)hWnd, hostname, port, timeout, 0, NULL, NULL, nat_t_error_code, (no_nat_t ? NULL : VPN_RUDP_SVC_NAME), try_start_ssl);
+		return WinConnectEx4((HWND)hWnd, hostname, port, timeout, 0, NULL, NULL, nat_t_error_code, (no_nat_t ? NULL : VPN_RUDP_SVC_NAME), try_start_ssl, hint_str);
 	}
 #endif	// OS_WIN32
 }
 
 // Connect with TCP/IP
 SOCK *TcpIpConnectEx(char *hostname, UINT port, bool *cancel_flag, void *hWnd, UINT *nat_t_error_code, bool no_nat_t, bool try_start_ssl, IP *ret_ip)
+{
+	return TcpIpConnectEx2(hostname, port, cancel_flag, hWnd, nat_t_error_code, no_nat_t, try_start_ssl, NULL, ret_ip);
+}
+SOCK *TcpIpConnectEx2(char *hostname, UINT port, bool *cancel_flag, void *hWnd, UINT *nat_t_error_code, bool no_nat_t, bool try_start_ssl, char *hint_str, IP *ret_ip)
 {
 	SOCK *s = NULL;
 	UINT dummy_int = 0;
@@ -6475,7 +6483,7 @@ SOCK *TcpIpConnectEx(char *hostname, UINT port, bool *cancel_flag, void *hWnd, U
 		return NULL;
 	}
 
-	s = TcpConnectEx3(hostname, port, 0, cancel_flag, hWnd, no_nat_t, nat_t_error_code, try_start_ssl, ret_ip);
+	s = TcpConnectEx4(hostname, port, 0, cancel_flag, hWnd, no_nat_t, nat_t_error_code, try_start_ssl, hint_str, ret_ip);
 	if (s == NULL)
 	{
 		return NULL;
diff --git a/src/Cedar/Protocol.h b/src/Cedar/Protocol.h
index 8e3db267..7dd91721 100644
--- a/src/Cedar/Protocol.h
+++ b/src/Cedar/Protocol.h
@@ -114,6 +114,7 @@ bool ServerAccept(CONNECTION *c);
 bool ClientConnect(CONNECTION *c);
 SOCK *ClientConnectToServer(CONNECTION *c);
 SOCK *TcpIpConnectEx(char *hostname, UINT port, bool *cancel_flag, void *hWnd, UINT *nat_t_error_code, bool no_nat_t, bool try_start_ssl, IP *ret_ip);
+SOCK *TcpIpConnectEx2(char *hostname, UINT port, bool *cancel_flag, void *hWnd, UINT *nat_t_error_code, bool no_nat_t, bool try_start_ssl, char *hint_str, IP *ret_ip);
 bool ClientUploadSignature(SOCK *s);
 bool ClientDownloadHello(CONNECTION *c, SOCK *s);
 bool ServerDownloadSignature(CONNECTION *c, char **error_detail_str);
@@ -121,6 +122,7 @@ bool ServerUploadHello(CONNECTION *c);
 bool ClientUploadAuth(CONNECTION *c);
 SOCK *ClientConnectGetSocket(CONNECTION *c, bool additional_connect);
 SOCK *TcpConnectEx3(char *hostname, UINT port, UINT timeout, bool *cancel_flag, void *hWnd, bool no_nat_t, UINT *nat_t_error_code, bool try_start_ssl, IP *ret_ip);
+SOCK *TcpConnectEx4(char *hostname, UINT port, UINT timeout, bool *cancel_flag, void *hWnd, bool no_nat_t, UINT *nat_t_error_code, bool try_start_ssl, char *hint_str, IP *ret_ip);
 
 UINT ProxyCodeToCedar(UINT code);
 
diff --git a/src/Cedar/SM.c b/src/Cedar/SM.c
index 917c60f3..5e505d4e 100644
--- a/src/Cedar/SM.c
+++ b/src/Cedar/SM.c
@@ -19360,7 +19360,14 @@ void SmEditSettingDlgInit(HWND hWnd, SM_EDIT_SETTING *p)
 	SetText(hWnd, E_ACCOUNT_NAME, s->Title);
 
 	// Host name
-	SetTextA(hWnd, E_HOSTNAME, s->ClientOption.Hostname);
+	char hostname[MAX_SIZE];
+	StrCpy(hostname, sizeof(hostname), s->ClientOption.Hostname);
+	if (IsEmptyStr(s->ClientOption.HintStr) == false)
+	{
+		StrCat(hostname, sizeof(hostname), "/");
+		StrCat(hostname, sizeof(hostname), s->ClientOption.HintStr);
+	}
+	SetTextA(hWnd, E_HOSTNAME, hostname);
 
 	// Port number
 	CbSetHeight(hWnd, C_PORT, 18);
@@ -19450,6 +19457,16 @@ void SmEditSettingDlgUpdate(HWND hWnd, SM_EDIT_SETTING *p)
 
 	GetTxtA(hWnd, E_HOSTNAME, tmp, sizeof(tmp));
 	Trim(tmp);
+	UINT i = SearchStrEx(tmp, "/", 0, false);
+	if (i != INFINITE)
+	{
+		StrCpy(s->ClientOption.HintStr, sizeof(s->ClientOption.HintStr), tmp + i + 1);
+		tmp[i] = 0;
+	}
+	else
+	{
+		s->ClientOption.HintStr[0] = 0;
+	}
 
 	if (StrCmpi(tmp, s->ClientOption.Hostname) != 0)
 	{
@@ -20211,6 +20228,13 @@ void SmLoadSettingList()
 
 			if (s != NULL)
 			{
+				// Migrate from old settings that mixed hint string with hostname
+				UINT i = SearchStrEx(s->ClientOption.Hostname, "/", 0, false);
+				if (i != INFINITE)
+				{
+					StrCpy(s->ClientOption.HintStr, sizeof(s->ClientOption.HintStr), s->ClientOption.Hostname + i + 1);
+					s->ClientOption.Hostname[i] = 0;
+				}
 				Add(sm->SettingList, s);
 			}
 			FreeBuf(b);
@@ -20273,6 +20297,7 @@ void SmInitDefaultSettingList()
 			Sha0(s->HashedPassword, "", 0);
 			UniStrCpy(s->ClientOption.AccountName, sizeof(s->ClientOption.AccountName), s->Title);
 			StrCpy(s->ClientOption.Hostname, sizeof(s->ClientOption.Hostname), "localhost");
+			s->ClientOption.HintStr[0] = 0;
 			s->ClientOption.Port = GC_DEFAULT_PORT;
 
 			Add(sm->SettingList, s);
@@ -20362,7 +20387,14 @@ void SmRefreshSettingEx(HWND hWnd, wchar_t *select_name)
 			UniFormat(tmp, sizeof(tmp), _UU("SM_MODE_HUB"), s->HubName);
 		}
 
-		StrToUni(tmp2, sizeof(tmp2), s->ClientOption.Hostname);
+		char hostname[MAX_SIZE];
+		StrCpy(hostname, sizeof(hostname), s->ClientOption.Hostname);
+		if (IsEmptyStr(s->ClientOption.HintStr) == false)
+		{
+			StrCat(hostname, sizeof(hostname), "/");
+			StrCat(hostname, sizeof(hostname), s->ClientOption.HintStr);
+		}
+		StrToUni(tmp2, sizeof(tmp2), hostname);
 
 		LvInsertAdd(b,
 			(s->ServerAdminMode ? ICO_SERVER_ONLINE : ICO_HUB),
@@ -20781,6 +20813,12 @@ void SmParseCommandLine()
 
 					UniStrCpy(o->AccountName, sizeof(o->AccountName), s->Title);
 					StrCpy(o->Hostname, sizeof(o->Hostname), host);
+					UINT i = SearchStrEx(o->Hostname, "/", 0, false);
+					if (i != INFINITE)
+					{
+						StrCpy(o->HintStr, sizeof(o->HintStr), o->Hostname + i + 1);
+						o->Hostname[i] = 0;
+					}
 					o->Port = port;
 					o->ProxyType = PROXY_DIRECT;
 					StrCpy(o->DeviceName, sizeof(o->DeviceName), "DUMMY");
diff --git a/src/Cedar/SMInner.h b/src/Cedar/SMInner.h
index 26420ff4..2a9158ec 100644
--- a/src/Cedar/SMInner.h
+++ b/src/Cedar/SMInner.h
@@ -41,7 +41,7 @@ typedef struct SETTING
 	char HubName[MAX_HUBNAME_LEN + 1];	// HUB name
 	UCHAR HashedPassword[SHA1_SIZE];	// Password
 	CLIENT_OPTION ClientOption;	// Client Option
-	UCHAR Reserved[10240 - sizeof(UINT) * 8 - SHA1_SIZE - HTTP_CUSTOM_HEADER_MAX_SIZE];	// Reserved area
+	UCHAR Reserved[10240 - sizeof(UINT) * 8 - SHA1_SIZE - HTTP_CUSTOM_HEADER_MAX_SIZE - MAX_HOST_NAME_LEN - 1];	// Reserved area
 } SETTING;
 
 // Structure declaration
diff --git a/src/Cedar/WinUi.c b/src/Cedar/WinUi.c
index 9a4c3bbb..f0c4a1cc 100644
--- a/src/Cedar/WinUi.c
+++ b/src/Cedar/WinUi.c
@@ -1329,7 +1329,7 @@ void WinConnectDlgThread(THREAD *thread, void *param)
 		nat_t_svc_name = d->nat_t_svc_name;
 	}
 
-	s = ConnectEx3(d->hostname, d->port, d->timeout, &d->cancel, nat_t_svc_name, &nat_t_error_code, d->try_start_ssl, false);
+	s = ConnectEx5(d->hostname, d->port, d->timeout, &d->cancel, nat_t_svc_name, &nat_t_error_code, d->try_start_ssl, false, d->hint_str, NULL);
 
 	d->ret_sock = s;
 	d->nat_t_error_code = nat_t_error_code;
@@ -1398,6 +1398,10 @@ UINT WinConnectDlgProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam, void *
 
 // TCP connection with showing the UI
 SOCK *WinConnectEx3(HWND hWnd, char *server, UINT port, UINT timeout, UINT icon_id, wchar_t *caption, wchar_t *info, UINT *nat_t_error_code, char *nat_t_svc_name, bool try_start_ssl)
+{
+	return WinConnectEx4(hWnd, server, port, timeout, icon_id, caption, info, nat_t_error_code, nat_t_svc_name, try_start_ssl, NULL);
+}
+SOCK *WinConnectEx4(HWND hWnd, char *server, UINT port, UINT timeout, UINT icon_id, wchar_t *caption, wchar_t *info, UINT *nat_t_error_code, char *nat_t_svc_name, bool try_start_ssl, char *hint_str)
 {
 	wchar_t tmp[MAX_SIZE];
 	wchar_t tmp2[MAX_SIZE];
@@ -1440,6 +1444,7 @@ SOCK *WinConnectEx3(HWND hWnd, char *server, UINT port, UINT timeout, UINT icon_
 	d.timeout = timeout;
 	d.hostname = server;
 	d.port = port;
+	d.hint_str = hint_str;
 	StrCpy(d.nat_t_svc_name, sizeof(d.nat_t_svc_name), nat_t_svc_name);
 
 	Dialog(hWnd, D_CONNECT, WinConnectDlgProc, &d);
diff --git a/src/Cedar/WinUi.h b/src/Cedar/WinUi.h
index 74cdd361..62d6c332 100644
--- a/src/Cedar/WinUi.h
+++ b/src/Cedar/WinUi.h
@@ -331,6 +331,7 @@ typedef struct WINCONNECT_DLG_DATA
 	char nat_t_svc_name[MAX_SIZE];
 	UINT nat_t_error_code;
 	bool try_start_ssl;
+	char *hint_str;
 } WINCONNECT_DLG_DATA;
 
 HBITMAP ResizeBitmap(HBITMAP hSrc, UINT src_x, UINT src_y, UINT dst_x, UINT dst_y);
@@ -694,6 +695,7 @@ HFONT GetMeiryoFontEx(UINT font_size);
 HFONT GetMeiryoFontEx2(UINT font_size, bool bold);
 bool ShowWindowsNetworkConnectionDialog();
 SOCK *WinConnectEx3(HWND hWnd, char *server, UINT port, UINT timeout, UINT icon_id, wchar_t *caption, wchar_t *info, UINT *nat_t_error_code, char *nat_t_svc_name, bool try_start_ssl);
+SOCK *WinConnectEx4(HWND hWnd, char *server, UINT port, UINT timeout, UINT icon_id, wchar_t *caption, wchar_t *info, UINT *nat_t_error_code, char *nat_t_svc_name, bool try_start_ssl, char *hint_str);
 UINT WinConnectDlgProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam, void *param);
 void WinConnectDlgThread(THREAD *thread, void *param);
 void NicInfo(UI_NICINFO *info);
diff --git a/src/Mayaqua/Network.c b/src/Mayaqua/Network.c
index ee97595d..6370f5e7 100644
--- a/src/Mayaqua/Network.c
+++ b/src/Mayaqua/Network.c
@@ -13979,7 +13979,7 @@ void ConnectThreadForIPv4(THREAD *thread, void *param)
 			Zero(&p4, sizeof(p4));
 
 			// p1: TCP
-			StrCpy(p1.Hostname, sizeof(p1.Hostname), p->Hostname_Original);
+			StrCpy(p1.Hostname, sizeof(p1.Hostname), p->Hostname);
 			Copy(&p1.Ip, ip, sizeof(IP));
 			p1.Port = p->Port;
 			p1.Timeout = p->Timeout;
@@ -13989,7 +13989,7 @@ void ConnectThreadForIPv4(THREAD *thread, void *param)
 			p1.CancelLock = NewLock();
 
 			// p2: NAT-T
-			StrCpy(p2.Hostname, sizeof(p2.Hostname), p->Hostname_Original);
+			StrCpy(p2.Hostname, sizeof(p2.Hostname), p->Hostname);
 			Copy(&p2.Ip, ip, sizeof(IP));
 			p2.Port = p->Port;
 			p2.Timeout = p->Timeout;
@@ -14002,7 +14002,7 @@ void ConnectThreadForIPv4(THREAD *thread, void *param)
 			p2.Delay = 30;		// Delay by 30ms
 
 			// p3: over ICMP
-			StrCpy(p3.Hostname, sizeof(p3.Hostname), p->Hostname_Original);
+			StrCpy(p3.Hostname, sizeof(p3.Hostname), p->Hostname);
 			Copy(&p3.Ip, ip, sizeof(IP));
 			p3.Port = p->Port;
 			p3.Timeout = p->Timeout;
@@ -14013,7 +14013,7 @@ void ConnectThreadForIPv4(THREAD *thread, void *param)
 			p3.Delay = 200;		// Delay by 200ms
 
 			// p4: over DNS
-			StrCpy(p4.Hostname, sizeof(p4.Hostname), p->Hostname_Original);
+			StrCpy(p4.Hostname, sizeof(p4.Hostname), p->Hostname);
 			Copy(&p4.Ip, ip, sizeof(IP));
 			p4.Port = p->Port;
 			p4.Timeout = p->Timeout;
@@ -14221,7 +14221,7 @@ void ConnectThreadForIPv4(THREAD *thread, void *param)
 
 		if (s != INVALID_SOCKET)
 		{
-			p->Sock = CreateTCPSock(s, false, &current_ip, p->No_Get_Hostname, p->Hostname_Original);
+			p->Sock = CreateTCPSock(s, false, &current_ip, p->No_Get_Hostname, p->Hostname);
 			break;
 		}
 	}
@@ -14308,7 +14308,7 @@ void ConnectThreadForIPv6(THREAD *thread, void *param)
 
 		if (s != INVALID_SOCKET)
 		{
-			p->Sock = CreateTCPSock(s, true, &current_ip, p->No_Get_Hostname, p->Hostname_Original);
+			p->Sock = CreateTCPSock(s, true, &current_ip, p->No_Get_Hostname, p->Hostname);
 			break;
 		}
 	}
@@ -14410,11 +14410,13 @@ SOCK *ConnectEx3(char *hostname, UINT port, UINT timeout, bool *cancel_flag, cha
 	return ConnectEx4(hostname, port, timeout, cancel_flag, nat_t_svc_name, nat_t_error_code, try_start_ssl, no_get_hostname, NULL);
 }
 SOCK *ConnectEx4(char *hostname, UINT port, UINT timeout, bool *cancel_flag, char *nat_t_svc_name, UINT *nat_t_error_code, bool try_start_ssl, bool no_get_hostname, IP *ret_ip)
+{
+	return ConnectEx5(hostname, port, timeout, cancel_flag, nat_t_svc_name, nat_t_error_code, try_start_ssl, no_get_hostname, NULL, ret_ip);
+}
+SOCK *ConnectEx5(char *hostname, UINT port, UINT timeout, bool *cancel_flag, char *nat_t_svc_name, UINT *nat_t_error_code, bool try_start_ssl, bool no_get_hostname, char *hint_str, IP *ret_ip)
 {
 	bool dummy = false;
 	bool use_natt = false;
-	char hostname_original[MAX_SIZE];
-	char hint_str[MAX_SIZE];
 	bool force_use_natt = false;
 	UINT dummy_int = 0;
 	IP dummy_ret_ip;
@@ -14442,33 +14444,15 @@ SOCK *ConnectEx4(char *hostname, UINT port, UINT timeout, bool *cancel_flag, cha
 		ret_ip = &dummy_ret_ip;
 	}
 
-	Zero(hint_str, sizeof(hint_str));
-	StrCpy(hostname_original, sizeof(hostname_original), hostname);
-
 	use_natt = (IsEmptyStr(nat_t_svc_name) ? false : true);
 
 	if (use_natt)
 	{
-		// In case of using NAT-T, split host name if the '/' is included in the host name
-		UINT i = SearchStrEx(hostname, "/", 0, false);
-
-		if (i == INFINITE)
+		if (IsEmptyStr(hint_str) == false)
 		{
-			// Not included
-			StrCpy(hostname_original, sizeof(hostname_original), hostname);
-		}
-		else
-		{
-			// Included
-			StrCpy(hostname_original, sizeof(hostname_original), hostname);
-			hostname_original[i] = 0;
-
 			// Force to use the NAT-T
 			force_use_natt = true;
 
-			// Copy the hint string
-			StrCpy(hint_str, sizeof(hint_str), hostname + i + 1);
-
 			if (StrCmpi(hint_str, "tcp") == 0 || StrCmpi(hint_str, "disable") == 0
 			        || StrCmpi(hint_str, "disabled") == 0
 			        || StrCmpi(hint_str, "no") == 0 || StrCmpi(hint_str, "none") == 0)
@@ -14479,10 +14463,6 @@ SOCK *ConnectEx4(char *hostname, UINT port, UINT timeout, bool *cancel_flag, cha
 			}
 		}
 	}
-	else
-	{
-		StrCpy(hostname_original, sizeof(hostname_original), hostname);
-	}
 
 	LIST *iplist_v6 = NULL;
 	LIST *iplist_v4 = NULL;
@@ -14506,7 +14486,7 @@ SOCK *ConnectEx4(char *hostname, UINT port, UINT timeout, bool *cancel_flag, cha
 	else
 	{
 		// Forward resolution
-		if (DnsResolveEx(&iplist_v6, &iplist_v4, hostname_original, 0, cancel_flag) == false)
+		if (DnsResolveEx(&iplist_v6, &iplist_v4, hostname, 0, cancel_flag) == false)
 		{
 			return NULL;
 		}
@@ -14532,7 +14512,6 @@ SOCK *ConnectEx4(char *hostname, UINT port, UINT timeout, bool *cancel_flag, cha
 		p6.Port = port;
 		p6.Timeout = timeout;
 		StrCpy(p6.Hostname, sizeof(p6.Hostname), hostname);
-		StrCpy(p6.Hostname_Original, sizeof(p6.Hostname_Original), hostname_original);
 		p6.No_Get_Hostname = no_get_hostname;
 		p6.CancelFlag = &cancel_flag2;
 		p6.NoDelayFlag = &no_delay_flag;
@@ -14551,7 +14530,6 @@ SOCK *ConnectEx4(char *hostname, UINT port, UINT timeout, bool *cancel_flag, cha
 		p4.Port = port;
 		p4.Timeout = timeout;
 		StrCpy(p4.Hostname, sizeof(p4.Hostname), hostname);
-		StrCpy(p4.Hostname_Original, sizeof(p4.Hostname_Original), hostname_original);
 		StrCpy(p4.HintStr, sizeof(p4.HintStr), hint_str);
 		p4.No_Get_Hostname = no_get_hostname;
 		p4.CancelFlag = &cancel_flag2;
diff --git a/src/Mayaqua/Network.h b/src/Mayaqua/Network.h
index 3475744b..d0b3be4a 100644
--- a/src/Mayaqua/Network.h
+++ b/src/Mayaqua/Network.h
@@ -802,7 +802,6 @@ struct CONNECT_SERIAL_PARAM
 	UINT Port;
 	UINT Timeout;
 	char Hostname[MAX_SIZE];
-	char Hostname_Original[MAX_SIZE];
 	char HintStr[MAX_SIZE];
 	bool No_Get_Hostname;
 	bool *CancelFlag;
@@ -1085,6 +1084,7 @@ SOCK *ConnectEx(char *hostname, UINT port, UINT timeout);
 SOCK *ConnectEx2(char *hostname, UINT port, UINT timeout, bool *cancel_flag);
 SOCK *ConnectEx3(char *hostname, UINT port, UINT timeout, bool *cancel_flag, char *nat_t_svc_name, UINT *nat_t_error_code, bool try_start_ssl, bool no_get_hostname);
 SOCK *ConnectEx4(char *hostname, UINT port, UINT timeout, bool *cancel_flag, char *nat_t_svc_name, UINT *nat_t_error_code, bool try_start_ssl, bool no_get_hostname, IP *ret_ip);
+SOCK *ConnectEx5(char *hostname, UINT port, UINT timeout, bool *cancel_flag, char *nat_t_svc_name, UINT *nat_t_error_code, bool try_start_ssl, bool no_get_hostname, char *hint_str, IP *ret_ip);
 SOCKET ConnectTimeoutIPv4(IP *ip, UINT port, UINT timeout, bool *cancel_flag);
 bool SetSocketBufferSize(SOCKET s, bool send, UINT size);
 UINT SetSocketBufferSizeWithBestEffort(SOCKET s, bool send, UINT size);