Uthernet II: add virtual DNS feature (PR #1097)

Uthernet II: add extended feature to virtualise DNS requests.
. This allows pure TCP/UDP sockets to run *without* MACRAW requests (and so without libpcap).
. Raw sockets will not work.
. Add configuration for Virtual DNS.
libpcap: ensure all functions check if the library is loaded before using it.
Uthernet 1: do NOT overwrite tfe_cannot_use as it should only reflect the availability of npcap on *this* system.
Add Copyright notice, and mention Virtual DNS in html.

AppleWinExpress2019.vcxproj

@@ -114,6 +114,7 @@
     <ClInclude Include="source\StrFormat.h" />
     <ClInclude Include="source\SynchronousEventManager.h" />
     <ClInclude Include="source\Tape.h" />
+    <ClInclude Include="source\Tfe\DNS.h" />
     <ClInclude Include="source\Tfe\IPRaw.h" />
     <ClInclude Include="source\Tfe\NetworkBackend.h" />
     <ClInclude Include="source\Tfe\Bpf.h" />
@@ -157,6 +158,7 @@
     <ClCompile Include="source\CardManager.cpp" />
     <ClCompile Include="source\CmdLine.cpp" />
     <ClCompile Include="source\Configuration\About.cpp" />
+    <ClCompile Include="source\Configuration\Config.cpp" />
     <ClCompile Include="source\Configuration\PageAdvanced.cpp" />
     <ClCompile Include="source\Configuration\PageConfig.cpp" />
     <ClCompile Include="source\Configuration\PageConfigTfe.cpp" />
@@ -223,6 +225,7 @@
     <ClCompile Include="source\StrFormat.cpp" />
     <ClCompile Include="source\SynchronousEventManager.cpp" />
     <ClCompile Include="source\Tape.cpp" />
+    <ClCompile Include="source\Tfe\DNS.cpp" />
     <ClCompile Include="source\Tfe\IPRaw.cpp" />
     <ClCompile Include="source\Tfe\NetworkBackend.cpp" />
     <ClCompile Include="source\Tfe\PCapBackend.cpp" />

AppleWinExpress2019.vcxproj.filters

@@ -262,6 +262,12 @@
     <ClCompile Include="source\Tfe\IPRaw.cpp">
       <Filter>Source Files\Uthernet</Filter>
     </ClCompile>
+    <ClCompile Include="source\Tfe\DNS.cpp">
+      <Filter>Source Files\Uthernet</Filter>
+    </ClCompile>
+    <ClCompile Include="source\Configuration\Config.cpp">
+      <Filter>Source Files\Configuration</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="source\CommonVICE\6510core.h">
@@ -600,6 +606,9 @@
     <ClInclude Include="source\Tfe\IPRaw.h">
       <Filter>Source Files\Uthernet</Filter>
     </ClInclude>
+    <ClInclude Include="source\Tfe\DNS.h">
+      <Filter>Source Files\Uthernet</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <Image Include="resource\Applewin.bmp">

help/uthernet.html

@@ -97,5 +97,8 @@
 				<li>after loading a save-state file, TCP and UDP sockets are closed</li>
 			</ul>
 		</P>
+		<P>The card implements a <A href="https://github.com/a2retrosystems/uthernet2/wiki/Virtual-W5100-with-DNS">Virtual DNS</A>
+			interface (not found on real hardware) for Apple II software to run without raw sockets:
+			this allows operation on any type of network.</P>
 		</body>
 </html>

resource/Applewin.rc

@@ -206,19 +206,22 @@ BEGIN
     PUSHBUTTON      "&Browse...",IDC_CIDERPRESS_BROWSE,161,202,50,14
 END
 
-IDD_TFE_SETTINGS_DIALOG DIALOGEX 0, 0, 270, 100
+IDD_TFE_SETTINGS_DIALOG DIALOGEX 0, 0, 271, 155
 STYLE DS_SETFONT | DS_MODALFRAME | DS_FIXEDSYS | WS_POPUP | WS_CAPTION | WS_SYSMENU
 CAPTION "Ethernet Settings"
 FONT 8, "MS Shell Dlg", 0, 0, 0x0
 BEGIN
     LTEXT           "Ethernet",IDC_TFE_SETTINGS_ENABLE_T,9,7,30,8
     COMBOBOX        IDC_TFE_SETTINGS_ENABLE,45,5,60,80,CBS_DROPDOWNLIST | WS_VSCROLL | WS_TABSTOP
+    CONTROL         "Virtual DNS",IDC_CHECK_TFE_VIRTUAL_DNS,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,150,7,50,8
     LTEXT           "Interface",IDC_TFE_SETTINGS_INTERFACE_T,9,24,30,8
     COMBOBOX        IDC_TFE_SETTINGS_INTERFACE,45,22,210,80,CBS_DROPDOWNLIST | WS_VSCROLL | WS_TABSTOP
     LTEXT           "",IDC_TFE_SETTINGS_INTERFACE_NAME,9,44,250,8
     LTEXT           "",IDC_TFE_SETTINGS_INTERFACE_DESC,9,60,250,8
-    DEFPUSHBUTTON   "Ok",IDOK,20,75,50,14
+    GROUPBOX        "Npcap",IDC_STATIC,5,75,260,55
-    PUSHBUTTON      "Cancel",IDCANCEL,80,75,50,14
+    LTEXT           "",IDC_TFE_NPCAP_INFO,12,86,240,36
+    DEFPUSHBUTTON   "Ok",IDOK,20,135,50,14
+    PUSHBUTTON      "Cancel",IDCANCEL,80,135,50,14
 END
 
 IDD_PROPPAGE_ADVANCED DIALOGEX 0, 0, 210, 217

resource/resource.h

@@ -119,6 +119,8 @@
 #define IDC_FOURPLAY_CONFIG             1087
 #define IDC_SNESMAX_CONFIG              1088
 #define IDC_CHECK_VIDHD_IN_SLOT3        1089
+#define IDC_CHECK_TFE_VIRTUAL_DNS       1090
+#define IDC_TFE_NPCAP_INFO              1091
 #define IDM_EXIT                        40001
 #define IDM_HELP                        40002
 #define IDM_ABOUT                       40003

source/Common.h

@@ -108,6 +108,7 @@ enum AppMode_e
 #define  REGVALUE_WINDOW_SCALE       "Window Scale"
 #define  REGVALUE_UTHERNET_ACTIVE       "Uthernet Active"	// GH#977: Deprecated from 1.30.5
 #define  REGVALUE_UTHERNET_INTERFACE    "Uthernet Interface"
+#define  REGVALUE_UTHERNET_VIRTUAL_DNS  "Uthernet Virtual DNS"
 #define  REGVALUE_SLOT4					"Slot 4"			// GH#977: Deprecated from 1.30.4
 #define  REGVALUE_SLOT5					"Slot 5"			// GH#977: Deprecated from 1.30.4
 #define  REGVALUE_VERSION				"Version"

source/Configuration/Config.cpp

@@ -0,0 +1,98 @@
+/*
+  AppleWin : An Apple //e emulator for Windows
+
+  Copyright (C) 1994-1996, Michael O'Brien
+  Copyright (C) 1999-2001, Oliver Schmidt
+  Copyright (C) 2002-2005, Tom Charlesworth
+  Copyright (C) 2006-2007, Tom Charlesworth, Michael Pohoreski
+
+  AppleWin is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  AppleWin is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with AppleWin; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#include "StdAfx.h"
+#include "Config.h"
+#include "../CardManager.h"
+#include "../Interface.h"	// VideoRefreshRate_e, GetVideoRefreshRate()
+#include "../Uthernet2.h"
+#include "../Tfe/PCapBackend.h"
+
+// zero initialise
+CConfigNeedingRestart::CConfigNeedingRestart()
+{
+	m_Apple2Type = A2TYPE_APPLE2;
+	m_CpuType = CPU_UNKNOWN;
+	memset(m_Slot, 0, sizeof(m_Slot));
+	m_SlotAux = CT_Empty;
+	m_tfeVirtualDNS = false;
+	m_bEnableTheFreezesF8Rom = 0;
+	m_uSaveLoadStateMsg = 0;
+	m_videoRefreshRate = VR_NONE;
+}
+
+// create from current global configuration
+CConfigNeedingRestart CConfigNeedingRestart::Create()
+{
+	CConfigNeedingRestart config;
+	config.Reload();
+	return config;
+}
+
+// update from current global configuration
+void CConfigNeedingRestart::Reload()
+{
+	m_Apple2Type = GetApple2Type();
+	m_CpuType = GetMainCpu();
+	CardManager& cardManager = GetCardMgr();
+	for (UINT slot = SLOT0; slot < NUM_SLOTS; slot++)
+		m_Slot[slot] = cardManager.QuerySlot(slot);
+	m_SlotAux = cardManager.QueryAux();
+	m_tfeInterface = PCapBackend::GetRegistryInterface(SLOT3);
+	m_tfeVirtualDNS = Uthernet2::GetRegistryVirtualDNS(SLOT3);
+	m_bEnableTheFreezesF8Rom = GetPropertySheet().GetTheFreezesF8Rom();
+	m_uSaveLoadStateMsg = 0;
+	m_videoRefreshRate = GetVideo().GetVideoRefreshRate();
+}
+
+const CConfigNeedingRestart& CConfigNeedingRestart::operator= (const CConfigNeedingRestart& other)
+{
+	m_Apple2Type = other.m_Apple2Type;
+	m_CpuType = other.m_CpuType;
+	memcpy(m_Slot, other.m_Slot, sizeof(m_Slot));
+	m_SlotAux = other.m_SlotAux;
+	m_tfeInterface = other.m_tfeInterface;
+	m_tfeVirtualDNS = other.m_tfeVirtualDNS;
+	m_bEnableTheFreezesF8Rom = other.m_bEnableTheFreezesF8Rom;
+	m_uSaveLoadStateMsg = other.m_uSaveLoadStateMsg;
+	m_videoRefreshRate = other.m_videoRefreshRate;
+	return *this;
+}
+
+bool CConfigNeedingRestart::operator== (const CConfigNeedingRestart& other) const
+{
+	return	m_Apple2Type == other.m_Apple2Type &&
+		m_CpuType == other.m_CpuType &&
+		memcmp(m_Slot, other.m_Slot, sizeof(m_Slot)) == 0 &&
+		m_SlotAux == other.m_SlotAux &&
+		m_tfeInterface == other.m_tfeInterface &&
+		m_tfeVirtualDNS == other.m_tfeVirtualDNS &&
+		m_bEnableTheFreezesF8Rom == other.m_bEnableTheFreezesF8Rom &&
+		m_uSaveLoadStateMsg == other.m_uSaveLoadStateMsg &&
+		m_videoRefreshRate == other.m_videoRefreshRate;
+}
+
+bool CConfigNeedingRestart::operator!= (const CConfigNeedingRestart& other) const
+{
+	return !operator==(other);
+}

source/Configuration/Config.h

@@ -1,86 +1,33 @@
 #pragma once
 
 #include "../Core.h"
-#include "../CardManager.h"
 #include "../CPU.h"
-#include "../DiskImage.h"	// Disk_Status_e
+#include "../Video.h"
-#include "../Harddisk.h"
-#include "../Interface.h"	// VideoRefreshRate_e, GetVideoRefreshRate()
-#include "../Tfe/PCapBackend.h"
 
 class CConfigNeedingRestart
 {
 public:
 	// zero initialise
-	CConfigNeedingRestart()
+	CConfigNeedingRestart();
-	{
-		m_Apple2Type = A2TYPE_APPLE2;
-		m_CpuType = CPU_UNKNOWN;
-		memset(m_Slot, 0, sizeof(m_Slot));
-		m_SlotAux = CT_Empty;
-		m_bEnableTheFreezesF8Rom = 0;
-		m_uSaveLoadStateMsg = 0;
-		m_videoRefreshRate = VR_NONE;
-	}
 
 	// create from current global configuration
-	static CConfigNeedingRestart Create()
+	static CConfigNeedingRestart Create();
-	{
-		CConfigNeedingRestart config;
-		config.Reload();
-		return config;
-	}
 
 	// update from current global configuration
-	void Reload()
+	void Reload();
-	{
-		m_Apple2Type = GetApple2Type();
-		m_CpuType = GetMainCpu();
-		CardManager& cardManager = GetCardMgr();
-		for (UINT slot = SLOT0; slot < NUM_SLOTS; slot++)
-			m_Slot[slot] = cardManager.QuerySlot(slot);
-		m_SlotAux = cardManager.QueryAux();
-		m_tfeInterface = PCapBackend::tfe_interface;
-		m_bEnableTheFreezesF8Rom = GetPropertySheet().GetTheFreezesF8Rom();
-		m_uSaveLoadStateMsg = 0;
-		m_videoRefreshRate = GetVideo().GetVideoRefreshRate();
-	}
 
-	const CConfigNeedingRestart& operator= (const CConfigNeedingRestart& other)
+	const CConfigNeedingRestart& operator= (const CConfigNeedingRestart& other);
-	{
-		m_Apple2Type = other.m_Apple2Type;
-		m_CpuType = other.m_CpuType;
-		memcpy(m_Slot, other.m_Slot, sizeof(m_Slot));
-		m_SlotAux = other.m_SlotAux;
-		m_tfeInterface = other.m_tfeInterface;
-		m_bEnableTheFreezesF8Rom = other.m_bEnableTheFreezesF8Rom;
-		m_uSaveLoadStateMsg = other.m_uSaveLoadStateMsg;
-		m_videoRefreshRate = other.m_videoRefreshRate;
-		return *this;
-	}
 
-	bool operator== (const CConfigNeedingRestart& other) const
+	bool operator== (const CConfigNeedingRestart& other) const;
-	{
-		return	m_Apple2Type == other.m_Apple2Type &&
-			m_CpuType == other.m_CpuType &&
-			memcmp(m_Slot, other.m_Slot, sizeof(m_Slot)) == 0 &&
-			m_SlotAux == other.m_SlotAux &&
-			m_tfeInterface == other.m_tfeInterface &&
-			m_bEnableTheFreezesF8Rom == other.m_bEnableTheFreezesF8Rom &&
-			m_uSaveLoadStateMsg == other.m_uSaveLoadStateMsg &&
-			m_videoRefreshRate == other.m_videoRefreshRate;
-	}
 
-	bool operator!= (const CConfigNeedingRestart& other) const
+	bool operator!= (const CConfigNeedingRestart& other) const;
-	{
-		return !operator==(other);
-	}
 
 	eApple2Type	m_Apple2Type;
 	eCpuType m_CpuType;
 	SS_CARDTYPE m_Slot[NUM_SLOTS];
 	SS_CARDTYPE m_SlotAux;
 	std::string m_tfeInterface;
+	bool m_tfeVirtualDNS;
 	UINT m_bEnableTheFreezesF8Rom;
 	UINT m_uSaveLoadStateMsg;
 	VideoRefreshRate_e m_videoRefreshRate;

source/Configuration/PageAdvanced.cpp

@@ -30,6 +30,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include "../ParallelPrinter.h"
 #include "../Registry.h"
 #include "../SaveState.h"
+#include "../CardManager.h"
 #include "../resource/resource.h"
 
 CPageAdvanced* CPageAdvanced::ms_this = 0;	// reinit'd in ctor

source/Configuration/PageConfig.cpp

@@ -30,6 +30,10 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include "../Windows/Win32Frame.h"
 #include "../Registry.h"
 #include "../SerialComms.h"
+#include "../CardManager.h"
+#include "../Uthernet2.h"
+#include "../Tfe/PCapBackend.h"
+#include "../Interface.h"
 #include "../resource/resource.h"
 
 CPageConfig* CPageConfig::ms_this = 0;	// reinit'd in ctor
@@ -114,6 +118,7 @@ INT_PTR CPageConfig::DlgProcInternal(HWND hWnd, UINT message, WPARAM wparam, LPA
 			ui_tfe_settings_dialog(hWnd);
 			m_PropertySheetHelper.GetConfigNew().m_Slot[SLOT3] = m_PageConfigTfe.m_tfe_selected;
 			m_PropertySheetHelper.GetConfigNew().m_tfeInterface = m_PageConfigTfe.m_tfe_interface_name;
+			m_PropertySheetHelper.GetConfigNew().m_tfeVirtualDNS = m_PageConfigTfe.m_tfe_virtual_dns;
 			InitOptions(hWnd);
 			break;
 
@@ -261,7 +266,8 @@ INT_PTR CPageConfig::DlgProcInternal(HWND hWnd, UINT message, WPARAM wparam, LPA
 					break;
 				}
 
-				m_PageConfigTfe.m_tfe_interface_name = PCapBackend::tfe_interface;
+				m_PageConfigTfe.m_tfe_interface_name = PCapBackend::GetRegistryInterface(SLOT3);
+				m_PageConfigTfe.m_tfe_virtual_dns = Uthernet2::GetRegistryVirtualDNS(SLOT3);
 			}
 
 			InitOptions(hWnd);

source/Configuration/PageConfigTfe.cpp

@@ -135,37 +135,16 @@ BOOL CPageConfigTfe::get_tfename(int number, std::string & name, std::string & d
 	return FALSE;
 }
 
-int CPageConfigTfe::gray_ungray_items(HWND hwnd)
+void CPageConfigTfe::gray_ungray_items(HWND hwnd)
 {
-	int enable;
+	const int enable = SendMessage(GetDlgItem(hwnd, IDC_TFE_SETTINGS_ENABLE), CB_GETCURSEL, 0, 0);
-	int number;
-
-	int disabled = 0;
-	PCapBackend::get_disabled_state(&disabled);
-
-	if (disabled)
-	{
-		EnableWindow(GetDlgItem(hwnd, IDC_TFE_SETTINGS_ENABLE_T), 0);
-		EnableWindow(GetDlgItem(hwnd, IDC_TFE_SETTINGS_ENABLE), 0);
-		EnableWindow(GetDlgItem(hwnd, IDOK), 0);
-		SetWindowText(GetDlgItem(hwnd,IDC_TFE_SETTINGS_INTERFACE_NAME), "");
-		SetWindowText(GetDlgItem(hwnd,IDC_TFE_SETTINGS_INTERFACE_DESC), "");
-		enable = 0;
-	}
-	else
-	{
-		enable = SendMessage(GetDlgItem(hwnd, IDC_TFE_SETTINGS_ENABLE), CB_GETCURSEL, 0, 0) ? 1 : 0;
-	}
-
-	EnableWindow(GetDlgItem(hwnd, IDC_TFE_SETTINGS_INTERFACE_T), enable);
-	EnableWindow(GetDlgItem(hwnd, IDC_TFE_SETTINGS_INTERFACE), enable);
 
 	if (enable)
 	{
 		std::string name;
 		std::string description;
 
-		number = SendMessage(GetDlgItem(hwnd, IDC_TFE_SETTINGS_INTERFACE), CB_GETCURSEL, 0, 0);
+		const int number = SendMessage(GetDlgItem(hwnd, IDC_TFE_SETTINGS_INTERFACE), CB_GETCURSEL, 0, 0);
 
 		if (get_tfename(number, name, description))
 		{
@@ -179,7 +158,7 @@ int CPageConfigTfe::gray_ungray_items(HWND hwnd)
 		SetWindowText(GetDlgItem(hwnd, IDC_TFE_SETTINGS_INTERFACE_DESC), "");
 	}
 
-	return disabled ? 1 : 0;
+	EnableWindow(GetDlgItem(hwnd, IDC_CHECK_TFE_VIRTUAL_DNS), enable == 2);
 }
 
 void CPageConfigTfe::init_tfe_dialog(HWND hwnd)
@@ -193,6 +172,23 @@ void CPageConfigTfe::init_tfe_dialog(HWND hwnd)
 	uilib_adjust_group_width(hwnd, ms_leftgroup);
 	uilib_move_group(hwnd, ms_rightgroup, xsize + 30);
 
+	if (PCapBackend::tfe_is_npcap_loaded())
+	{
+		const char * version = PCapBackend::tfe_lib_version();
+		SetWindowText(GetDlgItem(hwnd, IDC_TFE_NPCAP_INFO), version);
+	}
+	else
+	{
+		EnableWindow(GetDlgItem(hwnd, IDC_TFE_SETTINGS_INTERFACE), 0);
+		EnableWindow(GetDlgItem(hwnd, IDC_TFE_SETTINGS_INTERFACE_NAME), 0);
+		EnableWindow(GetDlgItem(hwnd, IDC_TFE_SETTINGS_INTERFACE_DESC), 0);
+
+		SetWindowText(GetDlgItem(hwnd, IDC_TFE_NPCAP_INFO),
+			"Limited Uthernet support is available on your system.\n\n"
+			"Install Npcap from https://npcap.com\n"
+			"or select Uthernet II with Virtual DNS.");
+	}
+
 	switch (m_tfe_selected)
 	{
 	case CT_Uthernet:
@@ -206,6 +202,8 @@ void CPageConfigTfe::init_tfe_dialog(HWND hwnd)
 		break;
 	}
 
+	CheckDlgButton(hwnd, IDC_CHECK_TFE_VIRTUAL_DNS, m_tfe_virtual_dns ? BST_CHECKED : BST_UNCHECKED);
+
 	temp_hwnd=GetDlgItem(hwnd,IDC_TFE_SETTINGS_ENABLE);
 	SendMessage(temp_hwnd, CB_ADDSTRING, 0, (LPARAM)"Disabled");
 	SendMessage(temp_hwnd, CB_ADDSTRING, 0, (LPARAM)"Uthernet");
@@ -244,22 +242,7 @@ void CPageConfigTfe::init_tfe_dialog(HWND hwnd)
 		PCapBackend::tfe_enumadapter_close();
 	}
 
-	if (gray_ungray_items(hwnd))
+	gray_ungray_items(hwnd);
-	{
-		/* we have a problem: TFE is disabled. Give a message to the user */
-		// TC (18 Dec 2017) this vicekb URL is a broken link now, so I copied it to the AppleWin repo, here:
-		// . https://github.com/AppleWin/AppleWin/blob/master/docs/VICE%20Knowledge%20Base%20-%20Article%2013-005.htm
-		MessageBox( hwnd,
-			"Uthernet support is not available on your system,\n"
-			"WPCAP.DLL cannot be loaded.\n\n"
-			"Install Npcap from\n\n"
-			"      https://npcap.com\n\n"
-			"to activate networking with AppleWin.",
-			"Uthernet support", MB_ICONINFORMATION|MB_OK);
-
-		/* just quit the dialog before it is open */
-		SendMessage( hwnd, WM_COMMAND, IDCANCEL, 0);
-	}
 }
 
 void CPageConfigTfe::save_tfe_dialog(HWND hwnd)
@@ -270,10 +253,8 @@ void CPageConfigTfe::save_tfe_dialog(HWND hwnd)
 	buffer[255] = 0;
 	GetDlgItemText(hwnd, IDC_TFE_SETTINGS_INTERFACE, buffer, sizeof(buffer)-1);
 
-	// RGJ - Added check for NULL interface so we don't set it active without a valid interface selected
-	if (strlen(buffer) > 0)
-	{
 	m_tfe_interface_name = buffer;
+
 	active_value = SendMessage(GetDlgItem(hwnd, IDC_TFE_SETTINGS_ENABLE), CB_GETCURSEL, 0, 0);
 	switch (active_value)
 	{
@@ -287,10 +268,6 @@ void CPageConfigTfe::save_tfe_dialog(HWND hwnd)
 		m_tfe_selected = CT_Empty;
 		break;
 	}
-	}
+
-	else
+	m_tfe_virtual_dns = IsDlgButtonChecked(hwnd, IDC_CHECK_TFE_VIRTUAL_DNS) ? 1 : 0;
-	{
-		m_tfe_selected = CT_Empty;
-		m_tfe_interface_name.clear();
-	}
 }

source/Configuration/PageConfigTfe.h

@@ -13,6 +13,7 @@ public:
 	{
 		CPageConfigTfe::ms_this = this;
 		m_tfe_selected = CT_Empty;
+		m_tfe_virtual_dns = false;
 	}
 	virtual ~CPageConfigTfe(){}
 
@@ -20,6 +21,7 @@ public:
 
 	SS_CARDTYPE m_tfe_selected;
 	std::string m_tfe_interface_name;
+	bool m_tfe_virtual_dns;
 
 protected:
 	// IPropertySheetPage
@@ -29,7 +31,7 @@ protected:
 
 private:
 	BOOL get_tfename(int number, std::string & name, std::string & description);
-	int gray_ungray_items(HWND hwnd);
+	void gray_ungray_items(HWND hwnd);
 	void init_tfe_dialog(HWND hwnd);
 	void save_tfe_dialog(HWND hwnd);
 

source/Configuration/PageDisk.cpp

@@ -29,7 +29,9 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include "../Windows/AppleWin.h"
 #include "../CardManager.h"
 #include "../Disk.h"	// Drive_e, Disk_Status_e
+#include "../HardDisk.h"
 #include "../Registry.h"
+#include "../Interface.h"
 #include "../resource/resource.h"
 
 CPageDisk* CPageDisk::ms_this = 0;	// reinit'd in ctor

source/Configuration/PropertySheetHelper.cpp

@@ -33,6 +33,8 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include "../Log.h"
 #include "../Registry.h"
 #include "../SaveState.h"
+#include "../Interface.h"
+#include "../Uthernet2.h"
 #include "../Tfe/PCapBackend.h"
 
 /*
@@ -336,7 +338,8 @@ void CPropertySheetHelper::ApplyNewConfig(const CConfigNeedingRestart& ConfigNew
 		SetSlot(slot, ConfigNew.m_Slot[slot]);
 
 	// unconditionally save it, as the previous SetSlot might have removed the setting
-	PCapBackend::tfe_SetRegistryInterface(slot, ConfigNew.m_tfeInterface);
+	PCapBackend::SetRegistryInterface(slot, ConfigNew.m_tfeInterface);
+	Uthernet2::SetRegistryVirtualDNS(slot, ConfigNew.m_tfeVirtualDNS);
 
 	slot = SLOT4;
 	if (CONFIG_CHANGED_LOCAL(m_Slot[slot]))
@@ -455,6 +458,9 @@ bool CPropertySheetHelper::HardwareConfigChanged(HWND hWnd)
 		if (CONFIG_CHANGED(m_tfeInterface))
 			strMsgMain += ". Uthernet interface has changed\n";
 
+		if (CONFIG_CHANGED(m_tfeVirtualDNS))
+			strMsgMain += ". Uthernet Virtual DNS has changed\n";
+
 		if (CONFIG_CHANGED(m_Slot[SLOT4]))
 			strMsgMain += GetSlot(SLOT4);
 

source/FrameBase.h

@@ -45,7 +45,7 @@ public:
 
 	// create the network backed for Uthernet 1 and 2
 	// useful to use libslirp in Linux
-	virtual std::shared_ptr<NetworkBackend> CreateNetworkBackend() = 0;
+	virtual std::shared_ptr<NetworkBackend> CreateNetworkBackend(const std::string & interfaceName) = 0;
 
 	// FindResource, MAKEINTRESOURCE, SizeofResource, LoadResource, LockResource
 	// Return pointer to resource if size is correct.

source/SaveState.cpp

@@ -41,6 +41,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include "Pravets.h"
 #include "Speaker.h"
 #include "Speech.h"
+#include "HardDisk.h"
 
 #include "Configuration/Config.h"
 #include "Configuration/IPropertySheet.h"

source/Tfe/DNS.cpp

@@ -0,0 +1,49 @@
+/*
+AppleWin : An Apple //e emulator for Windows
+
+Copyright (C) 2022, Andrea Odetti
+
+AppleWin is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+AppleWin is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with AppleWin; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#include "StdAfx.h"
+
+#include "DNS.h"
+
+#ifndef _MSC_VER
+#include <arpa/inet.h>
+#include <netdb.h>
+#endif
+
+uint32_t getHostByName(const std::string & name)
+{
+    const hostent * host = gethostbyname(name.c_str());
+    if (host && host->h_addrtype == AF_INET && host->h_length == sizeof(uint32_t))
+    {
+        const in_addr * addr = (const in_addr *)host->h_addr_list[0];
+        if (addr)
+        {
+            return addr->s_addr;
+        }
+    }
+    return 0;
+}
+
+const char * formatIP(const uint32_t address)
+{
+    in_addr in;
+    in.s_addr = address;
+    return inet_ntoa(in);
+}

source/Tfe/DNS.h

@@ -0,0 +1,4 @@
+#pragma once
+
+uint32_t getHostByName(const std::string & name);
+const char * formatIP(const uint32_t address);

source/Tfe/NetworkBackend.h

@@ -39,4 +39,7 @@ public:
 
 	// if the backend is usable
 	virtual bool isValid() = 0;
+
+	// get interface name
+	virtual const std::string & getInterfaceName() = 0;
 };

source/Tfe/PCapBackend.cpp

@@ -29,17 +29,15 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include <iphlpapi.h>
 #endif
 
-std::string PCapBackend::tfe_interface;
+PCapBackend::PCapBackend(const std::string & interfaceName) : m_interfaceName(interfaceName)
-
-PCapBackend::PCapBackend(const std::string & pcapInterface)
 {
-	tfePcapFP = TfePcapOpenAdapter(pcapInterface);
+	m_tfePcapFP = TfePcapOpenAdapter(interfaceName);
 }
 
 PCapBackend::~PCapBackend()
 {
-	TfePcapCloseAdapter(tfePcapFP);
+	TfePcapCloseAdapter(m_tfePcapFP);
-	tfePcapFP = NULL;
+	m_tfePcapFP = NULL;
 }
 
 void PCapBackend::transmit(
@@ -47,17 +45,17 @@ void PCapBackend::transmit(
     uint8_t *txframe        /* Pointer to the frame to be transmitted */
 )
 {
-    if (tfePcapFP)
+    if (m_tfePcapFP)
     {
-        tfe_arch_transmit(tfePcapFP, txlength, txframe);
+        tfe_arch_transmit(m_tfePcapFP, txlength, txframe);
     }
 }
 
 int PCapBackend::receive(const int size, uint8_t * rxframe)
 {
-    if (tfePcapFP)
+    if (m_tfePcapFP)
     {
-        return tfe_arch_receive(tfePcapFP, size, rxframe);
+        return tfe_arch_receive(m_tfePcapFP, size, rxframe);
     }
     else
     {
@@ -67,7 +65,7 @@ int PCapBackend::receive(const int size, uint8_t * rxframe)
 
 bool PCapBackend::isValid()
 {
-    return tfePcapFP;
+    return m_tfePcapFP;
 }
 
 void PCapBackend::update(const ULONG /* nExecutedCycles */)
@@ -85,6 +83,11 @@ void PCapBackend::getMACAddress(const uint32_t address, MACAddress & mac)
 #endif
 }
 
+const std::string & PCapBackend::getInterfaceName()
+{
+    return m_interfaceName;
+}
+
 int PCapBackend::tfe_enumadapter_open(void)
 {
     return tfe_arch_enumadapter_open();
@@ -100,13 +103,26 @@ int PCapBackend::tfe_enumadapter_close(void)
     return tfe_arch_enumadapter_close();
 }
 
-void PCapBackend::tfe_SetRegistryInterface(UINT slot, const std::string& name)
+const char * PCapBackend::tfe_lib_version(void)
+{
+    return tfe_arch_lib_version();
+}
+
+void PCapBackend::SetRegistryInterface(UINT slot, const std::string& name)
 {
     std::string regSection = RegGetConfigSlotSection(slot);
     RegSaveString(regSection.c_str(), REGVALUE_UTHERNET_INTERFACE, 1, name);
 }
 
-void PCapBackend::get_disabled_state(int * param)
+std::string PCapBackend::GetRegistryInterface(UINT slot)
 {
-    *param = tfe_cannot_use;
+    char interfaceName[MAX_PATH];
+    std::string regSection = RegGetConfigSlotSection(slot);
+    RegLoadString(regSection.c_str(), REGVALUE_UTHERNET_INTERFACE, TRUE, interfaceName, sizeof(interfaceName), TEXT(""));
+    return interfaceName;
+}
+
+int PCapBackend::tfe_is_npcap_loaded()
+{
+    return tfe_arch_is_npcap_loaded();
 }

source/Tfe/PCapBackend.h

@@ -10,7 +10,7 @@ typedef struct pcap pcap_t;
 class PCapBackend : public NetworkBackend
 {
 public:
-	PCapBackend(const std::string & pcapInterface);
+	PCapBackend(const std::string & interfaceName);
 
 	virtual ~PCapBackend();
 
@@ -32,8 +32,12 @@ public:
 	// get MAC for IPRAW (it is only supposed to handle addresses on the local network)
 	virtual void getMACAddress(const uint32_t address, MACAddress & mac);
 
-	static void tfe_SetRegistryInterface(UINT slot, const std::string& name);
+	// get interface name
-	static void get_disabled_state(int * param);
+	virtual const std::string & getInterfaceName();
+
+	// global registry functions
+	static void SetRegistryInterface(UINT slot, const std::string& name);
+	static std::string GetRegistryInterface(UINT slot);
 
 	/*
 	 These functions let the UI enumerate the available interfaces.
@@ -59,9 +63,10 @@ public:
 	static int tfe_enumadapter_open(void);
 	static int tfe_enumadapter(std::string & name, std::string & description);
 	static int tfe_enumadapter_close(void);
-
+	static const char * tfe_lib_version(void);
-	static std::string tfe_interface;
+	static int tfe_is_npcap_loaded();
 
 private:
-	pcap_t * tfePcapFP;
+	const std::string m_interfaceName;
+	pcap_t * m_tfePcapFP;
 };

source/Tfe/tfearch.cpp

@@ -28,6 +28,11 @@
 /* #define WPCAP */
 
 #ifdef _MSC_VER
+
+#ifndef NOMINMAX
+#define NOMINMAX
+#endif
+
 #include "pcap.h"
 #else
 // on Linux and Mac OS X, we use system's pcap.h, which needs to be included as <>
@@ -51,7 +56,8 @@
 
 #define TFE_DEBUG_WARN 1 /* this should not be deactivated */
 
-int tfe_cannot_use = 0;
+// once this is set, no further attempts to load npcap will be made
+static int tfe_cannot_use = 0;
 
 #ifdef _MSC_VER
 
@@ -113,7 +119,19 @@ void TfePcapFreeLibrary(void)
 static
 BOOL TfePcapLoadLibrary(void)
 {
-    if (!pcap_library) {
+    if (pcap_library)
+    {
+        // already loaded
+        return TRUE;
+    }
+
+    if (tfe_cannot_use)
+    {
+        // already failed
+        return FALSE;
+    }
+
+    // try to load
     if (!SetDllDirectory("C:\\Windows\\System32\\Npcap\\"))	// Prefer Npcap over WinPcap (GH#822)
     {
         const char* error = "Warning: SetDllDirectory() failed for Npcap";
@@ -123,7 +141,8 @@ BOOL TfePcapLoadLibrary(void)
 
     pcap_library = LoadLibrary("wpcap.dll");
 
-        if (!pcap_library) {
+    if (!pcap_library)
+    {
         tfe_cannot_use = 1;
         if(g_fh) fprintf(g_fh, "LoadLibrary WPCAP.DLL failed!\n" );
         return FALSE;
@@ -141,7 +160,6 @@ BOOL TfePcapLoadLibrary(void)
     GET_PROC_ADDRESS_AND_TEST(pcap_geterr);
     LogOutput("%s\n", p_pcap_lib_version());
     LogFileOutput("%s\n", p_pcap_lib_version());
-    }
 
     return TRUE;
 }
@@ -438,7 +456,7 @@ void TfePcapPacketHandler(u_char *param, const struct pcap_pkthdr *header, const
     /* determine the count of bytes which has been returned, 
      * but make sure not to overrun the buffer 
      */
-    pinternal->rxlength = min(pinternal->size, header->caplen);
+    pinternal->rxlength = std::min(pinternal->size, header->caplen);
 
     memcpy(pinternal->buffer, pkt_data, pinternal->rxlength);
 }
@@ -551,4 +569,19 @@ int tfe_arch_receive(pcap_t * TfePcapFP,
     return -1;
 }
 
+const char * tfe_arch_lib_version()
+{
+    if (!TfePcapLoadLibrary())
+    {
+        return 0;
+    }
+
+    return p_pcap_lib_version();
+}
+
+int tfe_arch_is_npcap_loaded()
+{
+    return TfePcapLoadLibrary();
+}
+
 //#endif /* #ifdef HAVE_TFE */

source/Tfe/tfearch.h

@@ -34,9 +34,6 @@
 extern void tfe_arch_set_mac(const BYTE mac[6]);
 extern void tfe_arch_set_hashfilter(const DWORD hash_mask[2]);
 
-/* Flag: Can we even use TFE, or is the hardware not available? */
-extern int tfe_cannot_use;
-
 struct pcap;
 typedef struct pcap pcap_t;
 
@@ -67,8 +64,11 @@ int tfe_arch_receive(pcap_t * TfePcapFP,
                      BYTE *pbuffer       /* where to store a frame */
                     );
 
+extern int tfe_arch_is_npcap_loaded();
 extern int tfe_arch_enumadapter_open(void);
 extern int tfe_arch_enumadapter(std::string & name, std::string & description);
 extern int tfe_arch_enumadapter_close(void);
 
+extern const char * tfe_arch_lib_version();
+
 #endif

source/Uthernet1.cpp

@@ -1011,7 +1011,8 @@ static BYTE __stdcall TfeIo (WORD programcounter, WORD address, BYTE write, BYTE
 
 void Uthernet1::InitializeIO(LPBYTE pCxRomPeripheral)
 {
-    networkBackend = GetFrame().CreateNetworkBackend();
+    const std::string interfaceName = PCapBackend::GetRegistryInterface(m_slot);
+    networkBackend = GetFrame().CreateNetworkBackend(interfaceName);
     if (networkBackend->isValid())
     {
         RegisterIoHandler(m_slot, TfeIo, TfeIo, TfeIoCxxx, TfeIoCxxx, this, NULL);
@@ -1058,10 +1059,10 @@ void Uthernet1::SaveSnapshot(class YamlSaveHelper& yamlSaveHelper)
     YamlSaveHelper::Label unit(yamlSaveHelper, "%s:\n", SS_YAML_KEY_STATE);
 
     yamlSaveHelper.SaveBool(SS_YAML_KEY_ENABLED, networkBackend->isValid() ? true : false);
-    yamlSaveHelper.SaveString(SS_YAML_KEY_NETWORK_INTERFACE, PCapBackend::tfe_interface);
+    yamlSaveHelper.SaveString(SS_YAML_KEY_NETWORK_INTERFACE, networkBackend->getInterfaceName());
 
     yamlSaveHelper.SaveBool(SS_YAML_KEY_STARTED_TX, tfe_started_tx ? true : false);
-    yamlSaveHelper.SaveBool(SS_YAML_KEY_CANNOT_USE, tfe_cannot_use ? true : false);
+    yamlSaveHelper.SaveBool(SS_YAML_KEY_CANNOT_USE, PCapBackend::tfe_is_npcap_loaded() ? false : false);
 
     yamlSaveHelper.SaveHexUint16(SS_YAML_KEY_TXCOLLECT_BUFFER, txcollect_buffer);
     yamlSaveHelper.SaveHexUint16(SS_YAML_KEY_RX_BUFFER, rx_buffer);
@@ -1083,10 +1084,13 @@ bool Uthernet1::LoadSnapshot(class YamlLoadHelper& yamlLoadHelper, UINT version)
 		ThrowErrorInvalidVersion(version);
 
     yamlLoadHelper.LoadBool(SS_YAML_KEY_ENABLED);  // FIXME: what is the point of this?
-    PCapBackend::tfe_interface = yamlLoadHelper.LoadString(SS_YAML_KEY_NETWORK_INTERFACE);
+    PCapBackend::SetRegistryInterface(m_slot, yamlLoadHelper.LoadString(SS_YAML_KEY_NETWORK_INTERFACE));
 
     tfe_started_tx = yamlLoadHelper.LoadBool(SS_YAML_KEY_STARTED_TX) ? true : false;
-    tfe_cannot_use = yamlLoadHelper.LoadBool(SS_YAML_KEY_CANNOT_USE) ? true : false;
+
+    // it is meaningless to restore this boolean flag
+    // as it depends on the availability of npcap on *this* pc
+    const bool tfe_cannot_use = yamlLoadHelper.LoadBool(SS_YAML_KEY_CANNOT_USE);
 
     txcollect_buffer = yamlLoadHelper.LoadUint(SS_YAML_KEY_TXCOLLECT_BUFFER);
     rx_buffer = yamlLoadHelper.LoadUint(SS_YAML_KEY_RX_BUFFER);
@@ -1117,7 +1121,5 @@ bool Uthernet1::LoadSnapshot(class YamlLoadHelper& yamlLoadHelper, UINT version)
     for (UINT i = 0; i < 6; i++)
         tfe_sideeffects_write_pp((TFE_PP_ADDR_MAC_ADDR + i) & ~1, i & 1);           // set tfe_ia_mac
 
-    PCapBackend::tfe_SetRegistryInterface(m_slot, PCapBackend::tfe_interface);
-
     return true;
 }

source/Uthernet2.cpp

@@ -25,7 +25,18 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include "Tfe/NetworkBackend.h"
 #include "Tfe/PCapBackend.h"
 #include "Tfe/IPRaw.h"
+#include "Tfe/DNS.h"
 #include "W5100.h"
+#include "../Registry.h"
+
+
+// Virtual DNS
+// Virtual DNS is an extension to the W5100
+// It enables DNS resolution by setting P3 = 1 for IP / TCP and UDP
+// the length-prefixed hostname is in 0x2A-0xFF is each socket memory
+// it can be identified with PTIMER = 0.
+// this means, one can use TCP & UDP without a NetworkBackend.
+
 
 // Linux uses EINPROGRESS while Windows returns WSAEWOULDBLOCK
 // when the connect() calls is ongoing
@@ -297,7 +308,6 @@ bool Socket::LoadSnapshot(YamlLoadHelper &yamlLoadHelper)
     sn_sr = yamlLoadHelper.LoadUint(SS_YAML_KEY_SOCKET_REGISTER);
 
     // transmit and receive sizes are restored from the card common registers
-
     switch (sn_sr)
     {
     case W5100_SN_SR_SOCK_MACRAW:
@@ -323,9 +333,30 @@ const std::string& Uthernet2::GetSnapshotCardName()
 
 Uthernet2::Uthernet2(UINT slot) : Card(CT_Uthernet2, slot)
 {
+#ifdef _MSC_VER
+    WSADATA wsaData;
+    myWSAStartup = WSAStartup(MAKEWORD(2, 2), &wsaData);
+    if (myWSAStartup)
+    {
+        const int error = sock_error();
+        LogFileOutput("U2: WSAStartup: error %" ERROR_FMT "\n", STRERROR(error));
+    }
+#endif
+
+    myVirtualDNSEnabled = GetRegistryVirtualDNS(slot);
     Reset(true);
 }
 
+Uthernet2::~Uthernet2()
+{
+#ifdef _MSC_VER
+    if (myWSAStartup == 0)
+    {
+        WSACleanup();
+    }
+#endif
+}
+
 void Uthernet2::setSocketModeRegister(const size_t i, const uint16_t address, const uint8_t value)
 {
     myMemory[address] = value;
@@ -338,16 +369,19 @@ void Uthernet2::setSocketModeRegister(const size_t i, const uint16_t address, co
 #endif
         break;
     case W5100_SN_MR_TCP:
+    case W5100_SN_MR_TCP_DNS:
 #ifdef U2_LOG_STATE
         LogFileOutput("U2: Mode[%" SIZE_T_FMT "]: TCP\n", i);
 #endif
         break;
     case W5100_SN_MR_UDP:
+    case W5100_SN_MR_UDP_DNS:
 #ifdef U2_LOG_STATE
         LogFileOutput("U2: Mode[%" SIZE_T_FMT "]: UDP\n", i);
 #endif
         break;
     case W5100_SN_MR_IPRAW:
+    case W5100_SN_MR_IPRAW_DNS:
 #ifdef U2_LOG_STATE
         LogFileOutput("U2: Mode[%" SIZE_T_FMT "]: IPRAW\n", i);
 #endif
@@ -698,13 +732,13 @@ void Uthernet2::sendDataIPRaw(const size_t i, std::vector<uint8_t> &payload)
     const uint8_t tos = myMemory[socket.registerAddress + W5100_SN_TOS];
     const uint8_t protocol = myMemory[socket.registerAddress + W5100_SN_PROTO];
     const uint32_t source = readAddress(myMemory.data() + W5100_SIPR0);
-    const uint32_t destination = readAddress(myMemory.data() + socket.registerAddress + W5100_SN_DIPR0);
+    const uint32_t dest = readAddress(myMemory.data() + socket.registerAddress + W5100_SN_DIPR0);
 
     const MACAddress * sourceMac = reinterpret_cast<const MACAddress *>(myMemory.data() + W5100_SHAR0);
     const MACAddress * destinationMac;
-    getMACAddress(destination, destinationMac);
+    getMACAddress(dest, destinationMac);
 
-    std::vector<uint8_t> packet = createETH2Frame(payload, sourceMac, destinationMac, ttl, tos, protocol, source, destination);
+    std::vector<uint8_t> packet = createETH2Frame(payload, sourceMac, destinationMac, ttl, tos, protocol, source, dest);
 
 #ifdef U2_LOG_TRAFFIC
     LogFileOutput("U2: Send IPRAW[%" SIZE_T_FMT "]: %" SIZE_T_FMT " (%" SIZE_T_FMT ") bytes\n", i, payload.size(), packet.size());
@@ -738,10 +772,9 @@ void Uthernet2::sendDataToSocket(const size_t i, std::vector<uint8_t> &data)
         sockaddr_in destination = {};
         destination.sin_family = AF_INET;
 
-        // already in network order
         // this seems to be ignored for TCP, and so we reuse the same code
-        const uint8_t *dest = myMemory.data() + socket.registerAddress + W5100_SN_DIPR0;
+        const uint32_t dest = readAddress(myMemory.data() + socket.registerAddress + W5100_SN_DIPR0);
-        destination.sin_addr.s_addr = *reinterpret_cast<const uint32_t *>(dest);
+        destination.sin_addr.s_addr = dest;
         destination.sin_port = *reinterpret_cast<const uint16_t *>(myMemory.data() + socket.registerAddress + W5100_SN_DPORT0);
 
         const ssize_t res = sendto(socket.myFD, reinterpret_cast<const char *>(data.data()), data.size(), 0, (const struct sockaddr *)&destination, sizeof(destination));
@@ -853,21 +886,38 @@ void Uthernet2::openSystemSocket(const size_t i, const int type, const int proto
 void Uthernet2::openSocket(const size_t i)
 {
     Socket &socket = mySockets[i];
+    socket.clearFD();
+
     const uint8_t mr = myMemory[socket.registerAddress + W5100_SN_MR];
     const uint8_t protocol = mr & W5100_SN_MR_PROTO_MASK;
+    const bool virtual_dns = protocol & W5100_SN_VIRTUAL_DNS;
+
+    // if virtual_dns is requested, but not enabled, we cannot handle it here.
+    if (virtual_dns && !myVirtualDNSEnabled)
+    {
+#ifdef U2_LOG_STATE
+        LogFileOutput("U2: Open[%" SIZE_T_FMT "]: virtual DNS not supported: %02x\n", i, mr);
+#endif
+        return;
+    }
+
     uint8_t &sr = socket.sn_sr;
+
     switch (protocol)
     {
     case W5100_SN_MR_IPRAW:
+    case W5100_SN_MR_IPRAW_DNS:
         sr = W5100_SN_SR_SOCK_IPRAW;
         break;
     case W5100_SN_MR_MACRAW:
         sr = W5100_SN_SR_SOCK_MACRAW;
         break;
     case W5100_SN_MR_TCP:
+    case W5100_SN_MR_TCP_DNS:
         openSystemSocket(i, SOCK_STREAM, IPPROTO_TCP, W5100_SN_SR_SOCK_INIT);
         break;
     case W5100_SN_MR_UDP:
+    case W5100_SN_MR_UDP_DNS:
         openSystemSocket(i, SOCK_DGRAM, IPPROTO_UDP, W5100_SN_SR_SOCK_UDP);
         break;
 #ifdef U2_LOG_UNKNOWN
@@ -875,6 +925,16 @@ void Uthernet2::openSocket(const size_t i)
         LogFileOutput("U2: Open[%" SIZE_T_FMT "]: unknown mode: %02x\n", i, mr);
 #endif
     }
+
+    switch (protocol)
+    {
+    case W5100_SN_MR_IPRAW_DNS:
+    case W5100_SN_MR_TCP_DNS:
+    case W5100_SN_MR_UDP_DNS:
+        resolveDNS(i);
+        break;
+    }
+
     resetRXTXBuffers(i); // needed?
 #ifdef U2_LOG_STATE
     LogFileOutput("U2: Open[%" SIZE_T_FMT "]: SR = %02x\n", i, sr);
@@ -890,17 +950,44 @@ void Uthernet2::closeSocket(const size_t i)
 #endif
 }
 
+void Uthernet2::resolveDNS(const size_t i)
+{
+    Socket &socket = mySockets[i];
+    uint32_t *dest = reinterpret_cast<uint32_t *>(myMemory.data() + socket.registerAddress + W5100_SN_DIPR0);
+    *dest = 0; // 0.0.0.0 signals failure by any reason
+
+    const uint8_t length = myMemory[socket.registerAddress + W5100_SN_DNS_NAME_LEN];
+    if (length <= W5100_SN_DNS_NAME_CPTY)
+    {
+        const uint8_t * start = myMemory.data() + socket.registerAddress + W5100_SN_DNS_NAME_BEGIN;
+        const std::string name(start, start + length);
+        const std::map<std::string, uint32_t>::iterator it = myDNSCache.find(name);
+        if (it != myDNSCache.end())
+        {
+            *dest = it->second;
+        }
+        else
+        {
+            *dest = getHostByName(name);
+            myDNSCache[name] = *dest;
+#ifdef U2_LOG_STATE
+            LogFileOutput("U2: DNS[%" SIZE_T_FMT "]: %s = %s\n", i, name.c_str(), formatIP(*dest));
+#endif
+        }
+    }
+}
+
 void Uthernet2::connectSocket(const size_t i)
 {
     Socket &socket = mySockets[i];
-    const uint8_t *dest = myMemory.data() + socket.registerAddress + W5100_SN_DIPR0;
+    const uint32_t dest = readAddress(myMemory.data() + socket.registerAddress + W5100_SN_DIPR0);
 
     sockaddr_in destination = {};
     destination.sin_family = AF_INET;
 
     // already in network order
     destination.sin_port = *reinterpret_cast<const uint16_t *>(myMemory.data() + socket.registerAddress + W5100_SN_DPORT0);
-    destination.sin_addr.s_addr = *reinterpret_cast<const uint32_t *>(dest);
+    destination.sin_addr.s_addr = dest;
 
     const int res = connect(socket.myFD, (struct sockaddr *)&destination, sizeof(destination));
 
@@ -910,7 +997,7 @@ void Uthernet2::connectSocket(const size_t i)
         socket.myErrno = 0;
 #ifdef U2_LOG_STATE
         const uint16_t port = readNetworkWord(myMemory.data() + socket.registerAddress + W5100_SN_DPORT0);
-        LogFileOutput("U2: TCP[%" SIZE_T_FMT "]: CONNECT to %d.%d.%d.%d:%d\n", i, dest[0], dest[1], dest[2], dest[3], port);
+        LogFileOutput("U2: TCP[%" SIZE_T_FMT "]: CONNECT to %s:%d\n", i, formatIP(dest), port);
 #endif
     }
     else
@@ -1130,11 +1217,18 @@ void Uthernet2::writeSocketRegister(const uint16_t address, const uint8_t value)
     case W5100_SN_RX_RD1:
         myMemory[address] = value;
         break;
-#ifdef U2_LOG_UNKNOWN
     default:
+        if (myVirtualDNSEnabled && loc >= W5100_SN_DNS_NAME_LEN)
+        {
+            myMemory[address] = value;
+        }
+        else
+        {
+#ifdef U2_LOG_UNKNOWN
             LogFileOutput("U2: Set unknown socket register[%d]: %04x\n", i, address);
-        break;
 #endif
+        }
+        break;
     };
 }
 
@@ -1216,8 +1310,10 @@ void Uthernet2::Reset(const bool powerCycle)
     {
         // dataAddress is NOT reset, see page 10 of Uthernet II
         myDataAddress = 0;
-        myNetworkBackend = GetFrame().CreateNetworkBackend();
+        const std::string interfaceName = PCapBackend::GetRegistryInterface(m_slot);
+        myNetworkBackend = GetFrame().CreateNetworkBackend(interfaceName);
         myARPCache.clear();
+        myDNSCache.clear();
     }
 
     mySockets.clear();
@@ -1247,8 +1343,12 @@ void Uthernet2::Reset(const bool powerCycle)
     myMemory[W5100_RCR]     = 0x08;
     setRXSizes(W5100_RMSR, 0x55);
     setTXSizes(W5100_TMSR, 0x55);
+    if (!myVirtualDNSEnabled)
+    {
+        // this is 0 if we support Virtual DNS
         myMemory[W5100_PTIMER]  = 0x28;
     }
+}
 
 BYTE Uthernet2::IO_C0(WORD programcounter, WORD address, BYTE write, BYTE value, ULONG nCycles)
 {
@@ -1367,7 +1467,11 @@ void Uthernet2::Update(const ULONG nExecutedCycles)
     }
 }
 
-static const UINT kUNIT_VERSION = 1;
+// Unit version history:
+// 2: Added: Virtual DNS
+static const UINT kUNIT_VERSION = 2;
+
+#define SS_YAML_KEY_VIRTUAL_DNS "Virtual DNS"
 #define SS_YAML_KEY_NETWORK_INTERFACE "Network Interface"
 
 #define SS_YAML_KEY_COMMON_REGISTERS "Common Registers"
@@ -1385,7 +1489,8 @@ void Uthernet2::SaveSnapshot(YamlSaveHelper &yamlSaveHelper)
     YamlSaveHelper::Slot slot(yamlSaveHelper, GetSnapshotCardName(), m_slot, kUNIT_VERSION);
 
     YamlSaveHelper::Label unit(yamlSaveHelper, "%s:\n", SS_YAML_KEY_STATE);
-    yamlSaveHelper.SaveString(SS_YAML_KEY_NETWORK_INTERFACE, PCapBackend::tfe_interface);
+    yamlSaveHelper.SaveString(SS_YAML_KEY_NETWORK_INTERFACE, myNetworkBackend->getInterfaceName());
+    yamlSaveHelper.SaveBool(SS_YAML_KEY_VIRTUAL_DNS, myVirtualDNSEnabled);
     yamlSaveHelper.SaveHexUint8(SS_YAML_KEY_MODE_REGISTER, myModeRegister);
     yamlSaveHelper.SaveHexUint16(SS_YAML_KEY_DATA_ADDRESS, myDataAddress);
 
@@ -1428,10 +1533,19 @@ bool Uthernet2::LoadSnapshot(YamlLoadHelper &yamlLoadHelper, UINT version)
     if (version < 1 || version > kUNIT_VERSION)
         ThrowErrorInvalidVersion(version);
 
-    PCapBackend::tfe_interface = yamlLoadHelper.LoadString(SS_YAML_KEY_NETWORK_INTERFACE);
+    PCapBackend::SetRegistryInterface(m_slot, yamlLoadHelper.LoadString(SS_YAML_KEY_NETWORK_INTERFACE));
-    PCapBackend::tfe_SetRegistryInterface(m_slot, PCapBackend::tfe_interface);
 
-    Reset(true); // AFTER the interface name has been restored
+    if (version >= 2)
+    {
+        myVirtualDNSEnabled = yamlLoadHelper.LoadBool(SS_YAML_KEY_VIRTUAL_DNS);
+    }
+    else
+    {
+        myVirtualDNSEnabled = false;
+    }
+    SetRegistryVirtualDNS(m_slot, myVirtualDNSEnabled);
+
+    Reset(true); // AFTER the parameters have been restored
 
     myModeRegister = yamlLoadHelper.LoadUint(SS_YAML_KEY_MODE_REGISTER);
     myDataAddress = yamlLoadHelper.LoadUint(SS_YAML_KEY_DATA_ADDRESS);
@@ -1475,3 +1589,17 @@ bool Uthernet2::LoadSnapshot(YamlLoadHelper &yamlLoadHelper, UINT version)
 
     return true;
 }
+
+void Uthernet2::SetRegistryVirtualDNS(UINT slot, const bool enabled)
+{
+    const std::string regSection = RegGetConfigSlotSection(slot);
+    RegSaveValue(regSection.c_str(), REGVALUE_UTHERNET_VIRTUAL_DNS, TRUE, enabled);
+}
+
+bool Uthernet2::GetRegistryVirtualDNS(UINT slot)
+{
+    const std::string regSection = RegGetConfigSlotSection(slot);
+    DWORD enabled = 0;
+    RegLoadValue(regSection.c_str(), REGVALUE_UTHERNET_VIRTUAL_DNS, TRUE, &enabled, 0);
+    return enabled != 0;
+}

source/Uthernet2.h

@@ -61,6 +61,7 @@ public:
     enum PacketDestination { HOST, BROADCAST, OTHER };
 
     Uthernet2(UINT slot);
+    virtual ~Uthernet2();
 
 	virtual void Destroy(void) {}
     virtual void InitializeIO(LPBYTE pCxRomPeripheral);
@@ -71,7 +72,17 @@ public:
 
     BYTE IO_C0(WORD programcounter, WORD address, BYTE write, BYTE value, ULONG nCycles);
 
+    // global registry functions
+    static void SetRegistryVirtualDNS(UINT slot, const bool enabled);
+    static bool GetRegistryVirtualDNS(UINT slot);
+
 private:
+    bool myVirtualDNSEnabled; // extended virtualisation of DNS (not present in the real U II card)
+
+#ifdef _MSC_VER
+    int myWSAStartup;
+#endif
+
     std::vector<uint8_t> myMemory;
     std::vector<Socket> mySockets;
     uint8_t myModeRegister;
@@ -82,8 +93,10 @@ private:
     // but in the interest of speeding up the emulator
     // we introduce one
     std::map<uint32_t, MACAddress> myARPCache;
+    std::map<std::string, uint32_t> myDNSCache;
 
     void getMACAddress(const uint32_t address, const MACAddress * & mac);
+    void resolveDNS(const size_t i);
 
     void setSocketModeRegister(const size_t i, const uint16_t address, const uint8_t value);
     void setTXSizes(const uint16_t address, uint8_t value);

source/Utilities.cpp

@@ -239,27 +239,15 @@ void LoadConfiguration(bool loadImages)
 
 		if (RegLoadValue(regSection.c_str(), REGVALUE_CARD_TYPE, TRUE, &dwTmp))
 		{
-			if (slot == SLOT3)
-			{
-				// this must happen before the card is instantitated
-				// TODO move to the card
-				if ((SS_CARDTYPE)dwTmp == CT_Uthernet || (SS_CARDTYPE)dwTmp == CT_Uthernet2)	// TODO: move this to when UthernetCard object is instantiated
-				{
-					std::string regSection = RegGetConfigSlotSection(slot);
-					if (RegLoadString(regSection.c_str(), REGVALUE_UTHERNET_INTERFACE, TRUE, szFilename, MAX_PATH, TEXT("")))
-						PCapBackend::tfe_interface = szFilename;
-				}
-			}
-
 			GetCardMgr().Insert(slot, (SS_CARDTYPE)dwTmp, false);
 		}
 		else	// legacy (AppleWin 1.30.3 or earlier)
 		{
 			if (slot == SLOT3)
 			{
-				// TODO: move this to when UthernetCard object is instantiated
 				RegLoadString(TEXT(REG_CONFIG), TEXT(REGVALUE_UTHERNET_INTERFACE), 1, szFilename, MAX_PATH, TEXT(""));
-				PCapBackend::tfe_interface = szFilename;
+				// copy it to the new location
+				PCapBackend::SetRegistryInterface(slot, szFilename);
 
 				DWORD tfeEnabled;
 				REGLOAD_DEFAULT(TEXT(REGVALUE_UTHERNET_ACTIVE), &tfeEnabled, 0);

source/W5100.h

@@ -46,6 +46,10 @@
 #define W5100_SN_MR_IPRAW         0x03
 #define W5100_SN_MR_MACRAW        0x04
 #define W5100_SN_MR_PPPOE         0x05
+#define W5100_SN_VIRTUAL_DNS      0x08  // not present on real hardware, see comment in Uthernet2.cpp
+#define W5100_SN_MR_TCP_DNS       (W5100_SN_VIRTUAL_DNS | W5100_SN_MR_TCP)
+#define W5100_SN_MR_UDP_DNS       (W5100_SN_VIRTUAL_DNS | W5100_SN_MR_UDP)
+#define W5100_SN_MR_IPRAW_DNS     (W5100_SN_VIRTUAL_DNS | W5100_SN_MR_IPRAW)
 
 #define W5100_SN_CR_OPEN          0x01
 #define W5100_SN_CR_LISTENT       0x02
@@ -88,6 +92,11 @@
 #define W5100_SN_RX_RD0           0x28  // RX Read Pointer
 #define W5100_SN_RX_RD1           0x29  // RX Read Pointer
 
+#define W5100_SN_DNS_NAME_LEN     0x2A  // these are not present on real hardware, see comment in Uthernet2.cpp
+#define W5100_SN_DNS_NAME_BEGIN   0x2B
+#define W5100_SN_DNS_NAME_END     0xFF
+#define W5100_SN_DNS_NAME_CPTY    (W5100_SN_DNS_NAME_END - W5100_SN_DNS_NAME_BEGIN)
+
 #define W5100_SN_SR_CLOSED        0x00
 #define W5100_SN_SR_SOCK_INIT     0x13
 #define W5100_SN_SR_ESTABLISHED   0x17

source/Windows/AppleWin.cpp

@@ -46,6 +46,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include "SoundCore.h"
 #include "Speaker.h"
 #include "LanguageCard.h"
+#include "CardManager.h"
 #ifdef USE_SPEECH_API
 #include "Speech.h"
 #endif

source/Windows/Win32Frame.cpp

@@ -625,8 +625,8 @@ std::string Win32Frame::Video_GetScreenShotFolder() const
 	return std::string();
 }
 
-std::shared_ptr<NetworkBackend> Win32Frame::CreateNetworkBackend()
+std::shared_ptr<NetworkBackend> Win32Frame::CreateNetworkBackend(const std::string & interfaceName)
 {
-	std::shared_ptr<NetworkBackend> backend(new PCapBackend(PCapBackend::tfe_interface));
+	std::shared_ptr<NetworkBackend> backend(new PCapBackend(interfaceName));
 	return backend;
 }

source/Windows/Win32Frame.h

@@ -57,7 +57,7 @@ public:
 
 	virtual std::string Video_GetScreenShotFolder() const;
 
-	virtual std::shared_ptr<NetworkBackend> CreateNetworkBackend();
+	virtual std::shared_ptr<NetworkBackend> CreateNetworkBackend(const std::string & interfaceName);
 
 	bool GetFullScreenShowSubunitStatus(void);
 	int GetFullScreenOffsetX(void);

source/Windows/WinFrame.cpp

@@ -48,6 +48,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include "Uthernet2.h"
 #include "Speaker.h"
 #include "Utilities.h"
+#include "CardManager.h"
 #include "../resource/resource.h"
 #include "Configuration/PropertySheet.h"
 #include "Debugger/Debug.h"