Merge branch 'debian/experimental-2.5'

14 files changed, 2562 insertions, 0 deletions

diff --git a/src/openvpnmsica/Makefile.am b/src/openvpnmsica/Makefile.am
new file mode 100644
index 0000000..9d18854
--- /dev/null
+++ b/src/openvpnmsica/Makefile.am
@@ -0,0 +1,56 @@
+#
+#  openvpnmsica -- Custom Action DLL to provide OpenVPN-specific support to MSI packages
+#
+#  Copyright (C) 2002-2018 OpenVPN Inc <sales@openvpn.net>
+#  Copyright (C) 2018-2020 Simon Rozman <simon@rozman.si>
+#
+#  This program is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License version 2
+#  as published by the Free Software Foundation.
+#
+#  This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+#  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+
+include $(top_srcdir)/build/ltrc.inc
+
+MAINTAINERCLEANFILES = $(srcdir)/Makefile.in
+
+EXTRA_DIST = \
+	openvpnmsica.vcxproj \
+	openvpnmsica.vcxproj.filters \
+	openvpnmsica.props \
+	openvpnmsica-Debug.props \
+	openvpnmsica-Release.props
+
+AM_CPPFLAGS = \
+	-I$(top_srcdir)/include -I$(top_srcdir)/src/compat
+
+AM_CFLAGS = \
+	$(TAP_CFLAGS)
+
+if WIN32
+lib_LTLIBRARIES = libopenvpnmsica.la
+libopenvpnmsica_la_CFLAGS = \
+	-municode -D_UNICODE \
+	-UNTDDI_VERSION -U_WIN32_WINNT \
+	-D_WIN32_WINNT=_WIN32_WINNT_VISTA \
+	-Wl,--kill-at
+libopenvpnmsica_la_LDFLAGS = -ladvapi32 -lole32 -lmsi -lsetupapi -liphlpapi -lshell32 -lshlwapi -lversion -no-undefined -avoid-version
+endif
+
+libopenvpnmsica_la_SOURCES = \
+	dllmain.c \
+	msiex.c msiex.h \
+	msica_arg.c msica_arg.h \
+	openvpnmsica.c openvpnmsica.h \
+	$(top_srcdir)/src/tapctl/basic.h \
+	$(top_srcdir)/src/tapctl/error.c $(top_srcdir)/src/tapctl/error.h \
+	$(top_srcdir)/src/tapctl/tap.c $(top_srcdir)/src/tapctl/tap.h \
+	openvpnmsica_resources.rc
diff --git a/src/openvpnmsica/dllmain.c b/src/openvpnmsica/dllmain.c
new file mode 100644
index 0000000..201fd9a
--- /dev/null
+++ b/src/openvpnmsica/dllmain.c
@@ -0,0 +1,198 @@
+/*
+ *  openvpnmsica -- Custom Action DLL to provide OpenVPN-specific support to MSI packages
+ *                  https://community.openvpn.net/openvpn/wiki/OpenVPNMSICA
+ *
+ *  Copyright (C) 2018 Simon Rozman <simon@rozman.si>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#elif defined(_MSC_VER)
+#include <config-msvc.h>
+#endif
+
+#include "openvpnmsica.h"
+#include "../tapctl/error.h"
+
+#include <windows.h>
+#include <msi.h>
+#include <msiquery.h>
+#ifdef _MSC_VER
+#pragma comment(lib, "msi.lib")
+#endif
+#include <stdio.h>
+#include <tchar.h>
+
+
+DWORD openvpnmsica_thread_data_idx = TLS_OUT_OF_INDEXES;
+
+
+/**
+ * DLL entry point
+ */
+BOOL WINAPI
+DllMain(
+    _In_ HINSTANCE hinstDLL,
+    _In_ DWORD dwReason,
+    _In_ LPVOID lpReserved)
+{
+    UNREFERENCED_PARAMETER(hinstDLL);
+    UNREFERENCED_PARAMETER(lpReserved);
+
+    switch (dwReason)
+    {
+        case DLL_PROCESS_ATTACH:
+            /* Allocate thread local storage index. */
+            openvpnmsica_thread_data_idx = TlsAlloc();
+            if (openvpnmsica_thread_data_idx == TLS_OUT_OF_INDEXES)
+            {
+                return FALSE;
+            }
+        /* Fall through. */
+
+        case DLL_THREAD_ATTACH:
+        {
+            /* Create thread local storage data. */
+            struct openvpnmsica_thread_data *s = (struct openvpnmsica_thread_data *)calloc(1, sizeof(struct openvpnmsica_thread_data));
+            if (s == NULL)
+            {
+                return FALSE;
+            }
+
+            TlsSetValue(openvpnmsica_thread_data_idx, s);
+            break;
+        }
+
+        case DLL_PROCESS_DETACH:
+            if (openvpnmsica_thread_data_idx != TLS_OUT_OF_INDEXES)
+            {
+                /* Free thread local storage data and index. */
+                free(TlsGetValue(openvpnmsica_thread_data_idx));
+                TlsFree(openvpnmsica_thread_data_idx);
+            }
+            break;
+
+        case DLL_THREAD_DETACH:
+            /* Free thread local storage data. */
+            free(TlsGetValue(openvpnmsica_thread_data_idx));
+            break;
+    }
+
+    return TRUE;
+}
+
+
+bool
+dont_mute(unsigned int flags)
+{
+    UNREFERENCED_PARAMETER(flags);
+
+    return true;
+}
+
+
+void
+x_msg_va(const unsigned int flags, const char *format, va_list arglist)
+{
+    /* Secure last error before it is overridden. */
+    DWORD dwResult = (flags & M_ERRNO) != 0 ? GetLastError() : ERROR_SUCCESS;
+
+    struct openvpnmsica_thread_data *s = (struct openvpnmsica_thread_data *)TlsGetValue(openvpnmsica_thread_data_idx);
+    if (s->hInstall == 0)
+    {
+        /* No MSI session, no fun. */
+        return;
+    }
+
+    /* Prepare the message record. The record will contain up to four fields. */
+    MSIHANDLE hRecordProg = MsiCreateRecord(4);
+
+    {
+        /* Field 2: The message string. */
+        char szBufStack[128];
+        int iResultLen = vsnprintf(szBufStack, _countof(szBufStack), format, arglist);
+        if (iResultLen < _countof(szBufStack))
+        {
+            /* Use from stack. */
+            MsiRecordSetStringA(hRecordProg, 2, szBufStack);
+        }
+        else
+        {
+            /* Allocate on heap and retry. */
+            char *szMessage = (char *)malloc(++iResultLen * sizeof(char));
+            if (szMessage != NULL)
+            {
+                vsnprintf(szMessage, iResultLen, format, arglist);
+                MsiRecordSetStringA(hRecordProg, 2, szMessage);
+                free(szMessage);
+            }
+            else
+            {
+                /* Use stack variant anyway, but make sure it's zero-terminated. */
+                szBufStack[_countof(szBufStack) - 1] = 0;
+                MsiRecordSetStringA(hRecordProg, 2, szBufStack);
+            }
+        }
+    }
+
+    if ((flags & M_ERRNO) == 0)
+    {
+        /* Field 1: MSI Error Code */
+        MsiRecordSetInteger(hRecordProg, 1, ERROR_MSICA);
+    }
+    else
+    {
+        /* Field 1: MSI Error Code */
+        MsiRecordSetInteger(hRecordProg, 1, ERROR_MSICA_ERRNO);
+
+        /* Field 3: The Windows error number. */
+        MsiRecordSetInteger(hRecordProg, 3, dwResult);
+
+        /* Field 4: The Windows error description. */
+        LPTSTR szErrMessage = NULL;
+        if (FormatMessage(
+                FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS,
+                0,
+                dwResult,
+                0,
+                (LPTSTR)&szErrMessage,
+                0,
+                NULL) && szErrMessage)
+        {
+            /* Trim trailing whitespace. Set terminator after the last non-whitespace character. This prevents excessive trailing line breaks. */
+            for (size_t i = 0, i_last = 0;; i++)
+            {
+                if (szErrMessage[i])
+                {
+                    if (!_istspace(szErrMessage[i]))
+                    {
+                        i_last = i + 1;
+                    }
+                }
+                else
+                {
+                    szErrMessage[i_last] = 0;
+                    break;
+                }
+            }
+            MsiRecordSetString(hRecordProg, 4, szErrMessage);
+            LocalFree(szErrMessage);
+        }
+    }
+
+    MsiProcessMessage(s->hInstall, INSTALLMESSAGE_ERROR, hRecordProg);
+    MsiCloseHandle(hRecordProg);
+}
diff --git a/src/openvpnmsica/msica_arg.c b/src/openvpnmsica/msica_arg.c
new file mode 100644
index 0000000..0014537
--- /dev/null
+++ b/src/openvpnmsica/msica_arg.c
@@ -0,0 +1,139 @@
+/*
+ *  openvpnmsica -- Custom Action DLL to provide OpenVPN-specific support to MSI packages
+ *                  https://community.openvpn.net/openvpn/wiki/OpenVPNMSICA
+ *
+ *  Copyright (C) 2018-2020 Simon Rozman <simon@rozman.si>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#elif defined(_MSC_VER)
+#include <config-msvc.h>
+#endif
+
+#include "msica_arg.h"
+#include "../tapctl/error.h"
+#include "../tapctl/tap.h"
+
+#include <windows.h>
+#include <malloc.h>
+
+
+void
+msica_arg_seq_init(_Inout_ struct msica_arg_seq *seq)
+{
+    seq->head = NULL;
+    seq->tail = NULL;
+}
+
+
+void
+msica_arg_seq_free(_Inout_ struct msica_arg_seq *seq)
+{
+    while (seq->head)
+    {
+        struct msica_arg *p = seq->head;
+        seq->head = seq->head->next;
+        free(p);
+    }
+    seq->tail = NULL;
+}
+
+
+void
+msica_arg_seq_add_head(
+    _Inout_ struct msica_arg_seq *seq,
+    _In_z_ LPCTSTR argument)
+{
+    size_t argument_size = (_tcslen(argument) + 1) * sizeof(TCHAR);
+    struct msica_arg *p = malloc(sizeof(struct msica_arg) + argument_size);
+    if (p == NULL)
+    {
+        msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, sizeof(struct msica_arg) + argument_size);
+    }
+    memcpy(p->val, argument, argument_size);
+    p->next = seq->head;
+    seq->head = p;
+    if (seq->tail == NULL)
+    {
+        seq->tail = p;
+    }
+}
+
+
+void
+msica_arg_seq_add_tail(
+    _Inout_ struct msica_arg_seq *seq,
+    _Inout_ LPCTSTR argument)
+{
+    size_t argument_size = (_tcslen(argument) + 1) * sizeof(TCHAR);
+    struct msica_arg *p = malloc(sizeof(struct msica_arg) + argument_size);
+    if (p == NULL)
+    {
+        msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, sizeof(struct msica_arg) + argument_size);
+    }
+    memcpy(p->val, argument, argument_size);
+    p->next = NULL;
+    *(seq->tail ? &seq->tail->next : &seq->head) = p;
+    seq->tail = p;
+}
+
+
+LPTSTR
+msica_arg_seq_join(_In_ const struct msica_arg_seq *seq)
+{
+    /* Count required space. */
+    size_t size = 2 /*x + zero-terminator*/;
+    for (struct msica_arg *p = seq->head; p != NULL; p = p->next)
+    {
+        size += _tcslen(p->val) + 1 /*space delimiter|zero-terminator*/;
+    }
+    size *= sizeof(TCHAR);
+
+    /* Allocate. */
+    LPTSTR str = malloc(size);
+    if (str == NULL)
+    {
+        msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, size);
+        return NULL;
+    }
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable: 4996) /* Using unsafe string functions: The space in s and termination of p->val has been implicitly verified at the beginning of this function. */
+#endif
+
+    /* Dummy argv[0] (i.e. executable name), for CommandLineToArgvW to work correctly when parsing this string. */
+    _tcscpy(str, TEXT("x"));
+
+    /* Join. */
+    LPTSTR s = str + 1 /*x*/;
+    for (struct msica_arg *p = seq->head; p != NULL; p = p->next)
+    {
+        /* Convert zero-terminator into space delimiter. */
+        s[0] = TEXT(' ');
+        s++;
+        /* Append argument. */
+        _tcscpy(s, p->val);
+        s += _tcslen(p->val);
+    }
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+    return str;
+}
diff --git a/src/openvpnmsica/msica_arg.h b/src/openvpnmsica/msica_arg.h
new file mode 100644
index 0000000..d2158e0
--- /dev/null
+++ b/src/openvpnmsica/msica_arg.h
@@ -0,0 +1,112 @@
+/*
+ *  openvpnmsica -- Custom Action DLL to provide OpenVPN-specific support to MSI packages
+ *                  https://community.openvpn.net/openvpn/wiki/OpenVPNMSICA
+ *
+ *  Copyright (C) 2018-2020 Simon Rozman <simon@rozman.si>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MSICA_ARG_H
+#define MSICA_ARG_H
+
+#include <windows.h>
+#include <tchar.h>
+#include "../tapctl/basic.h"
+
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable: 4200) /* Using zero-sized arrays in struct/union. */
+#endif
+
+
+/**
+ * Argument list
+ */
+struct msica_arg
+{
+    struct msica_arg *next; /** Pointer to the next argument in the sequence */
+    TCHAR val[];            /** Zero terminated argument string */
+};
+
+
+/**
+ * Argument sequence
+ */
+struct msica_arg_seq
+{
+    struct msica_arg *head; /** Pointer to the first argument in the sequence */
+    struct msica_arg *tail; /** Pointer to the last argument in the sequence */
+};
+
+
+/**
+ * Initializes argument sequence
+ *
+ * @param seq           Pointer to uninitialized argument sequence
+ */
+void
+msica_arg_seq_init(_Inout_ struct msica_arg_seq *seq);
+
+
+/**
+ * Frees argument sequence
+ *
+ * @param seq           Pointer to the argument sequence
+ */
+void
+msica_arg_seq_free(_Inout_ struct msica_arg_seq *seq);
+
+
+/**
+ * Inserts argument to the beginning of the argument sequence
+ *
+ * @param seq           Pointer to the argument sequence
+ *
+ * @param argument      Zero-terminated argument string to insert.
+ */
+void
+msica_arg_seq_add_head(
+    _Inout_ struct msica_arg_seq *seq,
+    _In_z_ LPCTSTR argument);
+
+
+/**
+ * Appends argument to the end of the argument sequence
+ *
+ * @param seq           Pointer to the argument sequence
+ *
+ * @param argument      Zero-terminated argument string to append.
+ */
+void
+msica_arg_seq_add_tail(
+    _Inout_ struct msica_arg_seq *seq,
+    _Inout_ LPCTSTR argument);
+
+/**
+ * Join arguments of the argument sequence into a space delimited string
+ *
+ * @param seq           Pointer to the argument sequence
+ *
+ * @return Joined argument string. Must be released with free() after use.
+ */
+LPTSTR
+msica_arg_seq_join(_In_ const struct msica_arg_seq *seq);
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+#endif /* ifndef MSICA_ARG_H */
diff --git a/src/openvpnmsica/msiex.c b/src/openvpnmsica/msiex.c
new file mode 100644
index 0000000..00265d0
--- /dev/null
+++ b/src/openvpnmsica/msiex.c
@@ -0,0 +1,265 @@
+/*
+ *  openvpnmsica -- Custom Action DLL to provide OpenVPN-specific support to MSI packages
+ *                  https://community.openvpn.net/openvpn/wiki/OpenVPNMSICA
+ *
+ *  Copyright (C) 2018 Simon Rozman <simon@rozman.si>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#elif defined(_MSC_VER)
+#include <config-msvc.h>
+#endif
+
+#include "msiex.h"
+#include "../tapctl/error.h"
+
+#include <windows.h>
+#include <malloc.h>
+#include <memory.h>
+#include <msiquery.h>
+#ifdef _MSC_VER
+#pragma comment(lib, "msi.lib")
+#endif
+
+
+UINT
+msi_get_string(
+    _In_ MSIHANDLE hInstall,
+    _In_z_ LPCTSTR szName,
+    _Out_ LPTSTR *pszValue)
+{
+    if (pszValue == NULL)
+    {
+        return ERROR_BAD_ARGUMENTS;
+    }
+
+    /* Try with stack buffer first. */
+    TCHAR szBufStack[128];
+    DWORD dwLength = _countof(szBufStack);
+    UINT uiResult = MsiGetProperty(hInstall, szName, szBufStack, &dwLength);
+    if (uiResult == ERROR_SUCCESS)
+    {
+        /* Copy from stack. */
+        *pszValue = (LPTSTR)malloc(++dwLength * sizeof(TCHAR));
+        if (*pszValue == NULL)
+        {
+            msg(M_FATAL, "%s: malloc(%u) failed", dwLength * sizeof(TCHAR));
+            return ERROR_OUTOFMEMORY;
+        }
+
+        memcpy(*pszValue, szBufStack, dwLength * sizeof(TCHAR));
+        return ERROR_SUCCESS;
+    }
+    else if (uiResult == ERROR_MORE_DATA)
+    {
+        /* Allocate on heap and retry. */
+        LPTSTR szBufHeap = (LPTSTR)malloc(++dwLength * sizeof(TCHAR));
+        if (szBufHeap == NULL)
+        {
+            msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, dwLength * sizeof(TCHAR));
+            return ERROR_OUTOFMEMORY;
+        }
+
+        uiResult = MsiGetProperty(hInstall, szName, szBufHeap, &dwLength);
+        if (uiResult == ERROR_SUCCESS)
+        {
+            *pszValue = szBufHeap;
+        }
+        else
+        {
+            free(szBufHeap);
+        }
+        return uiResult;
+    }
+    else
+    {
+        SetLastError(uiResult); /* MSDN does not mention MsiGetProperty() to set GetLastError(). But we do have an error code. Set last error manually. */
+        msg(M_NONFATAL | M_ERRNO, "%s: MsiGetProperty failed", __FUNCTION__);
+        return uiResult;
+    }
+}
+
+
+UINT
+msi_get_record_string(
+    _In_ MSIHANDLE hRecord,
+    _In_ unsigned int iField,
+    _Out_ LPTSTR *pszValue)
+{
+    if (pszValue == NULL)
+    {
+        return ERROR_BAD_ARGUMENTS;
+    }
+
+    /* Try with stack buffer first. */
+    TCHAR szBufStack[128];
+    DWORD dwLength = _countof(szBufStack);
+    UINT uiResult = MsiRecordGetString(hRecord, iField, szBufStack, &dwLength);
+    if (uiResult == ERROR_SUCCESS)
+    {
+        /* Copy from stack. */
+        *pszValue = (LPTSTR)malloc(++dwLength * sizeof(TCHAR));
+        if (*pszValue == NULL)
+        {
+            msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, dwLength * sizeof(TCHAR));
+            return ERROR_OUTOFMEMORY;
+        }
+
+        memcpy(*pszValue, szBufStack, dwLength * sizeof(TCHAR));
+        return ERROR_SUCCESS;
+    }
+    else if (uiResult == ERROR_MORE_DATA)
+    {
+        /* Allocate on heap and retry. */
+        LPTSTR szBufHeap = (LPTSTR)malloc(++dwLength * sizeof(TCHAR));
+        if (szBufHeap == NULL)
+        {
+            msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, dwLength * sizeof(TCHAR));
+            return ERROR_OUTOFMEMORY;
+        }
+
+        uiResult = MsiRecordGetString(hRecord, iField, szBufHeap, &dwLength);
+        if (uiResult == ERROR_SUCCESS)
+        {
+            *pszValue = szBufHeap;
+        }
+        else
+        {
+            free(szBufHeap);
+        }
+        return uiResult;
+    }
+    else
+    {
+        SetLastError(uiResult); /* MSDN does not mention MsiRecordGetString() to set GetLastError(). But we do have an error code. Set last error manually. */
+        msg(M_NONFATAL | M_ERRNO, "%s: MsiRecordGetString failed", __FUNCTION__);
+        return uiResult;
+    }
+}
+
+
+UINT
+msi_format_record(
+    _In_ MSIHANDLE hInstall,
+    _In_ MSIHANDLE hRecord,
+    _Out_ LPTSTR *pszValue)
+{
+    if (pszValue == NULL)
+    {
+        return ERROR_BAD_ARGUMENTS;
+    }
+
+    /* Try with stack buffer first. */
+    TCHAR szBufStack[128];
+    DWORD dwLength = _countof(szBufStack);
+    UINT uiResult = MsiFormatRecord(hInstall, hRecord, szBufStack, &dwLength);
+    if (uiResult == ERROR_SUCCESS)
+    {
+        /* Copy from stack. */
+        *pszValue = (LPTSTR)malloc(++dwLength * sizeof(TCHAR));
+        if (*pszValue == NULL)
+        {
+            msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, dwLength * sizeof(TCHAR));
+            return ERROR_OUTOFMEMORY;
+        }
+
+        memcpy(*pszValue, szBufStack, dwLength * sizeof(TCHAR));
+        return ERROR_SUCCESS;
+    }
+    else if (uiResult == ERROR_MORE_DATA)
+    {
+        /* Allocate on heap and retry. */
+        LPTSTR szBufHeap = (LPTSTR)malloc(++dwLength * sizeof(TCHAR));
+        if (szBufHeap == NULL)
+        {
+            msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, dwLength * sizeof(TCHAR));
+            return ERROR_OUTOFMEMORY;
+        }
+
+        uiResult = MsiFormatRecord(hInstall, hRecord, szBufHeap, &dwLength);
+        if (uiResult == ERROR_SUCCESS)
+        {
+            *pszValue = szBufHeap;
+        }
+        else
+        {
+            free(szBufHeap);
+        }
+        return uiResult;
+    }
+    else
+    {
+        SetLastError(uiResult); /* MSDN does not mention MsiFormatRecord() to set GetLastError(). But we do have an error code. Set last error manually. */
+        msg(M_NONFATAL | M_ERRNO, "%s: MsiFormatRecord failed", __FUNCTION__);
+        return uiResult;
+    }
+}
+
+
+UINT
+msi_format_field(
+    _In_ MSIHANDLE hInstall,
+    _In_ MSIHANDLE hRecord,
+    _In_ unsigned int iField,
+    _Out_ LPTSTR *pszValue)
+{
+    if (pszValue == NULL)
+    {
+        return ERROR_BAD_ARGUMENTS;
+    }
+
+    /* Read string to format. */
+    LPTSTR szValue = NULL;
+    UINT uiResult = msi_get_record_string(hRecord, iField, &szValue);
+    if (uiResult != ERROR_SUCCESS)
+    {
+        return uiResult;
+    }
+    if (szValue[0] == 0)
+    {
+        /* The string is empty. There's nothing left to do. */
+        *pszValue = szValue;
+        return ERROR_SUCCESS;
+    }
+
+    /* Create a temporary record. */
+    MSIHANDLE hRecordEx = MsiCreateRecord(1);
+    if (!hRecordEx)
+    {
+        uiResult = ERROR_INVALID_HANDLE;
+        msg(M_NONFATAL, "%s: MsiCreateRecord failed", __FUNCTION__);
+        goto cleanup_szValue;
+    }
+
+    /* Populate the record with data. */
+    uiResult = MsiRecordSetString(hRecordEx, 0, szValue);
+    if (uiResult != ERROR_SUCCESS)
+    {
+        SetLastError(uiResult); /* MSDN does not mention MsiRecordSetString() to set GetLastError(). But we do have an error code. Set last error manually. */
+        msg(M_NONFATAL | M_ERRNO, "%s: MsiRecordSetString failed", __FUNCTION__);
+        goto cleanup_hRecordEx;
+    }
+
+    /* Do the formatting. */
+    uiResult = msi_format_record(hInstall, hRecordEx, pszValue);
+
+cleanup_hRecordEx:
+    MsiCloseHandle(hRecordEx);
+cleanup_szValue:
+    free(szValue);
+    return uiResult;
+}
diff --git a/src/openvpnmsica/msiex.h b/src/openvpnmsica/msiex.h
new file mode 100644
index 0000000..d819b87
--- /dev/null
+++ b/src/openvpnmsica/msiex.h
@@ -0,0 +1,112 @@
+/*
+ *  openvpnmsica -- Custom Action DLL to provide OpenVPN-specific support to MSI packages
+ *                  https://community.openvpn.net/openvpn/wiki/OpenVPNMSICA
+ *
+ *  Copyright (C) 2018 Simon Rozman <simon@rozman.si>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MSIHLP_H
+#define MSIHLP_H
+
+#include <windows.h>
+#include <msi.h>
+#include "../tapctl/basic.h"
+
+
+/**
+ * Gets MSI property value
+ *
+ * @param hInstall      Handle to the installation provided to the DLL custom action
+ *
+ * @param szName        Property name
+ *
+ * @param pszValue      Pointer to string to retrieve property value. The string must
+ *                      be released with free() after use.
+ *
+ * @return ERROR_SUCCESS on success; Win32 error code otherwise
+ */
+UINT
+msi_get_string(
+    _In_ MSIHANDLE hInstall,
+    _In_z_ LPCTSTR szName,
+    _Out_ LPTSTR *pszValue);
+
+
+/**
+ * Gets MSI record string value
+ *
+ * @param hRecord       Handle to the record
+ *
+ * @param iField        Field index
+ *
+ * @param pszValue      Pointer to string to retrieve field value. The string must be
+ *                      released with free() after use.
+ *
+ * @return ERROR_SUCCESS on success; Win32 error code otherwise
+ */
+UINT
+msi_get_record_string(
+    _In_ MSIHANDLE hRecord,
+    _In_ unsigned int iField,
+    _Out_ LPTSTR *pszValue);
+
+
+/**
+ * Formats MSI record
+ *
+ * @param hInstall      Handle to the installation. This may be omitted, in which case only the
+ *                      record field parameters are processed and properties are not available
+ *                      for substitution.
+ *
+ * @param hRecord       Handle to the record to format. The template string must be stored in
+ *                      record field 0 followed by referenced data parameters.
+ *
+ * @param pszValue      Pointer to string to retrieve formatted value. The string must be
+ *                      released with free() after use.
+ *
+ * @return ERROR_SUCCESS on success; Win32 error code otherwise
+ */
+UINT
+msi_format_record(
+    _In_ MSIHANDLE hInstall,
+    _In_ MSIHANDLE hRecord,
+    _Out_ LPTSTR *pszValue);
+
+
+/**
+ * Formats MSI record field
+ *
+ * @param hInstall      Handle to the installation. This may be omitted, in which case only the
+ *                      record field parameters are processed and properties are not available
+ *                      for substitution.
+ *
+ * @param hRecord       Handle to the field record
+ *
+ * @param iField        Field index
+ *
+ * @param pszValue      Pointer to string to retrieve formatted value. The string must be
+ *                      released with free() after use.
+ *
+ * @return ERROR_SUCCESS on success; Win32 error code otherwise
+ */
+UINT
+msi_format_field(
+    _In_ MSIHANDLE hInstall,
+    _In_ MSIHANDLE hRecord,
+    _In_ unsigned int iField,
+    _Out_ LPTSTR *pszValue);
+
+#endif /* ifndef MSIHLP_H */
diff --git a/src/openvpnmsica/openvpnmsica-Debug.props b/src/openvpnmsica/openvpnmsica-Debug.props
new file mode 100644
index 0000000..43532cf
--- /dev/null
+++ b/src/openvpnmsica/openvpnmsica-Debug.props
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ImportGroup Label="PropertySheets">
+    <Import Project="openvpnmsica.props" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup />
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+    </ClCompile>
+  </ItemDefinitionGroup>
+  <ItemGroup />
+</Project>
\ No newline at end of file
diff --git a/src/openvpnmsica/openvpnmsica-Release.props b/src/openvpnmsica/openvpnmsica-Release.props
new file mode 100644
index 0000000..848fda8
--- /dev/null
+++ b/src/openvpnmsica/openvpnmsica-Release.props
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ImportGroup Label="PropertySheets">
+    <Import Project="openvpnmsica.props" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup />
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+    </ClCompile>
+  </ItemDefinitionGroup>
+  <ItemGroup />
+</Project>
\ No newline at end of file
diff --git a/src/openvpnmsica/openvpnmsica.c b/src/openvpnmsica/openvpnmsica.c
new file mode 100644
index 0000000..31e90bd
--- /dev/null
+++ b/src/openvpnmsica/openvpnmsica.c
@@ -0,0 +1,1215 @@
+/*
+ *  openvpnmsica -- Custom Action DLL to provide OpenVPN-specific support to MSI packages
+ *                  https://community.openvpn.net/openvpn/wiki/OpenVPNMSICA
+ *
+ *  Copyright (C) 2018-2020 Simon Rozman <simon@rozman.si>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#elif defined(_MSC_VER)
+#include <config-msvc.h>
+#endif
+#include <winsock2.h> /* Must be included _before_ <windows.h> */
+
+#include "openvpnmsica.h"
+#include "msica_arg.h"
+#include "msiex.h"
+
+#include "../tapctl/basic.h"
+#include "../tapctl/error.h"
+#include "../tapctl/tap.h"
+
+#include <windows.h>
+#include <iphlpapi.h>
+#include <malloc.h>
+#include <memory.h>
+#include <msiquery.h>
+#include <shellapi.h>
+#include <shlwapi.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <tchar.h>
+
+#ifdef _MSC_VER
+#pragma comment(lib, "advapi32.lib")
+#pragma comment(lib, "iphlpapi.lib")
+#pragma comment(lib, "shell32.lib")
+#pragma comment(lib, "shlwapi.lib")
+#pragma comment(lib, "version.lib")
+#endif
+
+
+/**
+ * Local constants
+ */
+
+#define MSICA_ADAPTER_TICK_SIZE (16*1024) /** Amount of tick space to reserve for one TAP/TUN adapter creation/deletition. */
+
+
+/**
+ * Joins an argument sequence and sets it to the MSI property.
+ *
+ * @param hInstall      Handle to the installation provided to the DLL custom action
+ *
+ * @param szProperty    MSI property name to set to the joined argument sequence.
+ *
+ * @param seq           The argument sequence.
+ *
+ * @return ERROR_SUCCESS on success; An error code otherwise
+ */
+static UINT
+setup_sequence(
+    _In_ MSIHANDLE hInstall,
+    _In_z_ LPCTSTR szProperty,
+    _In_ struct msica_arg_seq *seq)
+{
+    UINT uiResult;
+    LPTSTR szSequence = msica_arg_seq_join(seq);
+    uiResult = MsiSetProperty(hInstall, szProperty, szSequence);
+    free(szSequence);
+    if (uiResult != ERROR_SUCCESS)
+    {
+        SetLastError(uiResult); /* MSDN does not mention MsiSetProperty() to set GetLastError(). But we do have an error code. Set last error manually. */
+        msg(M_NONFATAL | M_ERRNO, "%s: MsiSetProperty(\"%" PRIsLPTSTR "\") failed", __FUNCTION__, szProperty);
+        return uiResult;
+    }
+    return ERROR_SUCCESS;
+}
+
+
+#ifdef _DEBUG
+
+/**
+ * Pops up a message box creating a time window to attach a debugger to the installer process in
+ * order to debug custom actions.
+ *
+ * @param szFunctionName  Function name that triggered the pop-up. Displayed in message box's
+ *                        title.
+ */
+static void
+_debug_popup(_In_z_ LPCTSTR szFunctionName)
+{
+    TCHAR szTitle[0x100], szMessage[0x100+MAX_PATH], szProcessPath[MAX_PATH];
+
+    /* Compose pop-up title. The dialog title will contain function name to ease the process
+     * locating. Mind that Visual Studio displays window titles on the process list. */
+    _stprintf_s(szTitle, _countof(szTitle), TEXT("%s v%s"), szFunctionName, TEXT(PACKAGE_VERSION));
+
+    /* Get process name. */
+    GetModuleFileName(NULL, szProcessPath, _countof(szProcessPath));
+    LPCTSTR szProcessName = _tcsrchr(szProcessPath, TEXT('\\'));
+    szProcessName = szProcessName ? szProcessName + 1 : szProcessPath;
+
+    /* Compose the pop-up message. */
+    _stprintf_s(
+        szMessage, _countof(szMessage),
+        TEXT("The %s process (PID: %u) has started to execute the %s custom action.\r\n")
+        TEXT("\r\n")
+        TEXT("If you would like to debug the custom action, attach a debugger to this process and set breakpoints before dismissing this dialog.\r\n")
+        TEXT("\r\n")
+        TEXT("If you are not debugging this custom action, you can safely ignore this message."),
+        szProcessName,
+        GetCurrentProcessId(),
+        szFunctionName);
+
+    MessageBox(NULL, szMessage, szTitle, MB_OK);
+}
+
+#define debug_popup(f) _debug_popup(f)
+#else  /* ifdef _DEBUG */
+#define debug_popup(f)
+#endif /* ifdef _DEBUG */
+
+
+/**
+ * Detects if the OpenVPNService service is in use (running or paused) and sets
+ * OPENVPNSERVICE to the service process PID, or its path if it is set to
+ * auto-start, but not running.
+ *
+ * @param hInstall      Handle to the installation provided to the DLL custom action
+ *
+ * @return ERROR_SUCCESS on success; An error code otherwise
+ *         See: https://msdn.microsoft.com/en-us/library/windows/desktop/aa368072.aspx
+ */
+static UINT
+set_openvpnserv_state(_In_ MSIHANDLE hInstall)
+{
+    UINT uiResult;
+
+    /* Get Service Control Manager handle. */
+    SC_HANDLE hSCManager = OpenSCManager(NULL, SERVICES_ACTIVE_DATABASE, SC_MANAGER_CONNECT);
+    if (hSCManager == NULL)
+    {
+        uiResult = GetLastError();
+        msg(M_NONFATAL | M_ERRNO, "%s: OpenSCManager() failed", __FUNCTION__);
+        return uiResult;
+    }
+
+    /* Get OpenVPNService service handle. */
+    SC_HANDLE hService = OpenService(hSCManager, TEXT("OpenVPNService"), SERVICE_QUERY_STATUS | SERVICE_QUERY_CONFIG);
+    if (hService == NULL)
+    {
+        uiResult = GetLastError();
+        if (uiResult == ERROR_SERVICE_DOES_NOT_EXIST)
+        {
+            /* This is not actually an error. */
+            goto cleanup_OpenSCManager;
+        }
+        msg(M_NONFATAL | M_ERRNO, "%s: OpenService(\"OpenVPNService\") failed", __FUNCTION__);
+        goto cleanup_OpenSCManager;
+    }
+
+    /* Query service status. */
+    SERVICE_STATUS_PROCESS ssp;
+    DWORD dwBufSize;
+    if (QueryServiceStatusEx(hService, SC_STATUS_PROCESS_INFO, (LPBYTE)&ssp, sizeof(ssp), &dwBufSize))
+    {
+        switch (ssp.dwCurrentState)
+        {
+            case SERVICE_START_PENDING:
+            case SERVICE_RUNNING:
+            case SERVICE_STOP_PENDING:
+            case SERVICE_PAUSE_PENDING:
+            case SERVICE_PAUSED:
+            case SERVICE_CONTINUE_PENDING:
+            {
+                /* Service is started (kind of). Set OPENVPNSERVICE property to service PID. */
+                TCHAR szPID[10 /*MAXDWORD in decimal*/ + 1 /*terminator*/];
+                _stprintf_s(
+                    szPID, _countof(szPID),
+                    TEXT("%u"),
+                    ssp.dwProcessId);
+
+                uiResult = MsiSetProperty(hInstall, TEXT("OPENVPNSERVICE"), szPID);
+                if (uiResult != ERROR_SUCCESS)
+                {
+                    SetLastError(uiResult); /* MSDN does not mention MsiSetProperty() to set GetLastError(). But we do have an error code. Set last error manually. */
+                    msg(M_NONFATAL | M_ERRNO, "%s: MsiSetProperty(\"OPENVPNSERVICE\") failed", __FUNCTION__);
+                }
+
+                /* We know user is using the service. Skip auto-start setting check. */
+                goto cleanup_OpenService;
+            }
+            break;
+        }
+    }
+    else
+    {
+        uiResult = GetLastError();
+        msg(M_NONFATAL | M_ERRNO, "%s: QueryServiceStatusEx(\"OpenVPNService\") failed", __FUNCTION__);
+    }
+
+    /* Service is not started. Is it set to auto-start? */
+    /* MSDN describes the maximum buffer size for QueryServiceConfig() to be 8kB. */
+    /* This is small enough to fit on stack. */
+    BYTE _buffer_8k[8192];
+    LPQUERY_SERVICE_CONFIG pQsc = (LPQUERY_SERVICE_CONFIG)_buffer_8k;
+    dwBufSize = sizeof(_buffer_8k);
+    if (!QueryServiceConfig(hService, pQsc, dwBufSize, &dwBufSize))
+    {
+        uiResult = GetLastError();
+        msg(M_NONFATAL | M_ERRNO, "%s: QueryServiceStatusEx(\"QueryServiceConfig\") failed", __FUNCTION__);
+        goto cleanup_OpenService;
+    }
+
+    if (pQsc->dwStartType <= SERVICE_AUTO_START)
+    {
+        /* Service is set to auto-start. Set OPENVPNSERVICE property to its path. */
+        uiResult = MsiSetProperty(hInstall, TEXT("OPENVPNSERVICE"), pQsc->lpBinaryPathName);
+        if (uiResult != ERROR_SUCCESS)
+        {
+            SetLastError(uiResult); /* MSDN does not mention MsiSetProperty() to set GetLastError(). But we do have an error code. Set last error manually. */
+            msg(M_NONFATAL | M_ERRNO, "%s: MsiSetProperty(\"OPENVPNSERVICE\") failed", __FUNCTION__);
+            goto cleanup_OpenService;
+        }
+    }
+
+    uiResult = ERROR_SUCCESS;
+
+cleanup_OpenService:
+    CloseServiceHandle(hService);
+cleanup_OpenSCManager:
+    CloseServiceHandle(hSCManager);
+    return uiResult;
+}
+
+
+static UINT
+find_adapters(
+    _In_ MSIHANDLE hInstall,
+    _In_z_ LPCTSTR szzHardwareIDs,
+    _In_z_ LPCTSTR szAdaptersPropertyName,
+    _In_z_ LPCTSTR szActiveAdaptersPropertyName)
+{
+    UINT uiResult;
+
+    /* Get network adapters with given hardware ID. */
+    struct tap_adapter_node *pAdapterList = NULL;
+    uiResult = tap_list_adapters(NULL, szzHardwareIDs, &pAdapterList);
+    if (uiResult != ERROR_SUCCESS)
+    {
+        return uiResult;
+    }
+    else if (pAdapterList == NULL)
+    {
+        /* No adapters - no fun. */
+        return ERROR_SUCCESS;
+    }
+
+    /* Get IPv4/v6 info for all network adapters. Actually, we're interested in link status only: up/down? */
+    PIP_ADAPTER_ADDRESSES pAdapterAdresses = NULL;
+    ULONG ulAdapterAdressesSize = 16*1024;
+    for (size_t iteration = 0; iteration < 2; iteration++)
+    {
+        pAdapterAdresses = (PIP_ADAPTER_ADDRESSES)malloc(ulAdapterAdressesSize);
+        if (pAdapterAdresses == NULL)
+        {
+            msg(M_NONFATAL, "%s: malloc(%u) failed", __FUNCTION__, ulAdapterAdressesSize);
+            uiResult = ERROR_OUTOFMEMORY; goto cleanup_pAdapterList;
+        }
+
+        ULONG ulResult = GetAdaptersAddresses(
+            AF_UNSPEC,
+            GAA_FLAG_SKIP_UNICAST | GAA_FLAG_SKIP_ANYCAST | GAA_FLAG_SKIP_MULTICAST | GAA_FLAG_SKIP_DNS_SERVER | GAA_FLAG_SKIP_FRIENDLY_NAME | GAA_FLAG_INCLUDE_ALL_INTERFACES,
+            NULL,
+            pAdapterAdresses,
+            &ulAdapterAdressesSize);
+
+        if (ulResult == ERROR_SUCCESS)
+        {
+            break;
+        }
+
+        free(pAdapterAdresses);
+        if (ulResult != ERROR_BUFFER_OVERFLOW)
+        {
+            SetLastError(ulResult); /* MSDN does not mention GetAdaptersAddresses() to set GetLastError(). But we do have an error code. Set last error manually. */
+            msg(M_NONFATAL | M_ERRNO, "%s: GetAdaptersAddresses() failed", __FUNCTION__);
+            uiResult = ulResult; goto cleanup_pAdapterList;
+        }
+    }
+
+    /* Count adapters. */
+    size_t adapter_count = 0;
+    for (struct tap_adapter_node *pAdapter = pAdapterList; pAdapter; pAdapter = pAdapter->pNext)
+    {
+        adapter_count++;
+    }
+
+    /* Prepare semicolon delimited list of TAP adapter ID(s) and active TAP adapter ID(s). */
+    LPTSTR
+        szAdapters     = (LPTSTR)malloc(adapter_count * (38 /*GUID*/ + 1 /*separator/terminator*/) * sizeof(TCHAR)),
+        szAdaptersTail = szAdapters;
+    if (szAdapters == NULL)
+    {
+        msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, adapter_count * (38 /*GUID*/ + 1 /*separator/terminator*/) * sizeof(TCHAR));
+        uiResult = ERROR_OUTOFMEMORY; goto cleanup_pAdapterAdresses;
+    }
+
+    LPTSTR
+        szAdaptersActive     = (LPTSTR)malloc(adapter_count * (38 /*GUID*/ + 1 /*separator/terminator*/) * sizeof(TCHAR)),
+        szAdaptersActiveTail = szAdaptersActive;
+    if (szAdaptersActive == NULL)
+    {
+        msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, adapter_count * (38 /*GUID*/ + 1 /*separator/terminator*/) * sizeof(TCHAR));
+        uiResult = ERROR_OUTOFMEMORY; goto cleanup_szAdapters;
+    }
+
+    for (struct tap_adapter_node *pAdapter = pAdapterList; pAdapter; pAdapter = pAdapter->pNext)
+    {
+        /* Convert adapter GUID to UTF-16 string. (LPOLESTR defaults to LPWSTR) */
+        LPOLESTR szAdapterId = NULL;
+        StringFromIID((REFIID)&pAdapter->guid, &szAdapterId);
+
+        /* Append to the list of TAP adapter ID(s). */
+        if (szAdapters < szAdaptersTail)
+        {
+            *(szAdaptersTail++) = TEXT(';');
+        }
+        memcpy(szAdaptersTail, szAdapterId, 38 * sizeof(TCHAR));
+        szAdaptersTail += 38;
+
+        /* If this adapter is active (connected), add it to the list of active TAP adapter ID(s). */
+        for (PIP_ADAPTER_ADDRESSES p = pAdapterAdresses; p; p = p->Next)
+        {
+            OLECHAR szId[38 /*GUID*/ + 1 /*terminator*/];
+            GUID guid;
+            if (MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, p->AdapterName, -1, szId, _countof(szId)) > 0
+                && SUCCEEDED(IIDFromString(szId, &guid))
+                && memcmp(&guid, &pAdapter->guid, sizeof(GUID)) == 0)
+            {
+                if (p->OperStatus == IfOperStatusUp)
+                {
+                    /* This TAP adapter is active (connected). */
+                    if (szAdaptersActive < szAdaptersActiveTail)
+                    {
+                        *(szAdaptersActiveTail++) = TEXT(';');
+                    }
+                    memcpy(szAdaptersActiveTail, szAdapterId, 38 * sizeof(TCHAR));
+                    szAdaptersActiveTail += 38;
+                }
+                break;
+            }
+        }
+        CoTaskMemFree(szAdapterId);
+    }
+    szAdaptersTail      [0] = 0;
+    szAdaptersActiveTail[0] = 0;
+
+    /* Set Installer properties. */
+    uiResult = MsiSetProperty(hInstall, szAdaptersPropertyName, szAdapters);
+    if (uiResult != ERROR_SUCCESS)
+    {
+        SetLastError(uiResult); /* MSDN does not mention MsiSetProperty() to set GetLastError(). But we do have an error code. Set last error manually. */
+        msg(M_NONFATAL | M_ERRNO, "%s: MsiSetProperty(\"%s\") failed", __FUNCTION__, szAdaptersPropertyName);
+        goto cleanup_szAdaptersActive;
+    }
+    uiResult = MsiSetProperty(hInstall, szActiveAdaptersPropertyName, szAdaptersActive);
+    if (uiResult != ERROR_SUCCESS)
+    {
+        SetLastError(uiResult); /* MSDN does not mention MsiSetProperty() to set GetLastError(). But we do have an error code. Set last error manually. */
+        msg(M_NONFATAL | M_ERRNO, "%s: MsiSetProperty(\"%s\") failed", __FUNCTION__, szActiveAdaptersPropertyName);
+        goto cleanup_szAdaptersActive;
+    }
+
+cleanup_szAdaptersActive:
+    free(szAdaptersActive);
+cleanup_szAdapters:
+    free(szAdapters);
+cleanup_pAdapterAdresses:
+    free(pAdapterAdresses);
+cleanup_pAdapterList:
+    tap_free_adapter_list(pAdapterList);
+    return uiResult;
+}
+
+
+UINT __stdcall
+FindSystemInfo(_In_ MSIHANDLE hInstall)
+{
+#ifdef _MSC_VER
+#pragma comment(linker, DLLEXP_EXPORT)
+#endif
+
+    debug_popup(TEXT(__FUNCTION__));
+
+    BOOL bIsCoInitialized = SUCCEEDED(CoInitialize(NULL));
+
+    OPENVPNMSICA_SAVE_MSI_SESSION(hInstall);
+
+    set_openvpnserv_state(hInstall);
+    find_adapters(
+        hInstall,
+        TEXT("root\\") TEXT(TAP_WIN_COMPONENT_ID) TEXT("\0") TEXT(TAP_WIN_COMPONENT_ID) TEXT("\0"),
+        TEXT("TAPWINDOWS6ADAPTERS"),
+        TEXT("ACTIVETAPWINDOWS6ADAPTERS"));
+    find_adapters(
+        hInstall,
+        TEXT("Wintun") TEXT("\0"),
+        TEXT("WINTUNADAPTERS"),
+        TEXT("ACTIVEWINTUNADAPTERS"));
+
+    if (bIsCoInitialized)
+    {
+        CoUninitialize();
+    }
+    return ERROR_SUCCESS;
+}
+
+
+UINT __stdcall
+CloseOpenVPNGUI(_In_ MSIHANDLE hInstall)
+{
+#ifdef _MSC_VER
+#pragma comment(linker, DLLEXP_EXPORT)
+#endif
+    UNREFERENCED_PARAMETER(hInstall); /* This CA is does not interact with MSI session (report errors, access properties, tables, etc.). */
+
+    debug_popup(TEXT(__FUNCTION__));
+
+    /* Find OpenVPN GUI window. */
+    HWND hWnd = FindWindow(TEXT("OpenVPN-GUI"), NULL);
+    if (hWnd)
+    {
+        /* Ask it to close and wait for 100ms. Unfortunately, this will succeed only for recent OpenVPN GUI that do not run elevated. */
+        SendMessage(hWnd, WM_CLOSE, 0, 0);
+        Sleep(100);
+    }
+
+    return ERROR_SUCCESS;
+}
+
+
+UINT __stdcall
+StartOpenVPNGUI(_In_ MSIHANDLE hInstall)
+{
+#ifdef _MSC_VER
+#pragma comment(linker, DLLEXP_EXPORT)
+#endif
+
+    debug_popup(TEXT(__FUNCTION__));
+
+    UINT uiResult;
+    BOOL bIsCoInitialized = SUCCEEDED(CoInitialize(NULL));
+
+    OPENVPNMSICA_SAVE_MSI_SESSION(hInstall);
+
+    /* Create and populate a MSI record. */
+    MSIHANDLE hRecord = MsiCreateRecord(1);
+    if (!hRecord)
+    {
+        uiResult = ERROR_INVALID_HANDLE;
+        msg(M_NONFATAL, "%s: MsiCreateRecord failed", __FUNCTION__);
+        goto cleanup_CoInitialize;
+    }
+    uiResult = MsiRecordSetString(hRecord, 0, TEXT("\"[#bin.openvpn_gui.exe]\""));
+    if (uiResult != ERROR_SUCCESS)
+    {
+        SetLastError(uiResult); /* MSDN does not mention MsiRecordSetString() to set GetLastError(). But we do have an error code. Set last error manually. */
+        msg(M_NONFATAL | M_ERRNO, "%s: MsiRecordSetString failed", __FUNCTION__);
+        goto cleanup_MsiCreateRecord;
+    }
+
+    /* Format string. */
+    TCHAR szStackBuf[MAX_PATH];
+    DWORD dwPathSize = _countof(szStackBuf);
+    LPTSTR szPath = szStackBuf;
+    uiResult = MsiFormatRecord(hInstall, hRecord, szPath, &dwPathSize);
+    if (uiResult == ERROR_MORE_DATA)
+    {
+        /* Allocate buffer on heap (+1 for terminator), and retry. */
+        szPath = (LPTSTR)malloc((++dwPathSize) * sizeof(TCHAR));
+        if (szPath == NULL)
+        {
+            msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, dwPathSize * sizeof(TCHAR));
+            uiResult = ERROR_OUTOFMEMORY; goto cleanup_MsiCreateRecord;
+        }
+
+        uiResult = MsiFormatRecord(hInstall, hRecord, szPath, &dwPathSize);
+    }
+    if (uiResult != ERROR_SUCCESS)
+    {
+        SetLastError(uiResult); /* MSDN does not mention MsiFormatRecord() to set GetLastError(). But we do have an error code. Set last error manually. */
+        msg(M_NONFATAL | M_ERRNO, "%s: MsiFormatRecord failed", __FUNCTION__);
+        goto cleanup_malloc_szPath;
+    }
+
+    /* Launch the OpenVPN GUI. */
+    SHELLEXECUTEINFO sei = {
+        .cbSize = sizeof(SHELLEXECUTEINFO),
+        .fMask  = SEE_MASK_FLAG_NO_UI, /* Don't show error UI, we'll display it. */
+        .lpFile = szPath,
+        .nShow  = SW_SHOWNORMAL
+    };
+    if (!ShellExecuteEx(&sei))
+    {
+        uiResult = GetLastError();
+        msg(M_NONFATAL | M_ERRNO, "%s: ShellExecuteEx(%s) failed", __FUNCTION__, szPath);
+        goto cleanup_malloc_szPath;
+    }
+
+    uiResult = ERROR_SUCCESS;
+
+cleanup_malloc_szPath:
+    if (szPath != szStackBuf)
+    {
+        free(szPath);
+    }
+cleanup_MsiCreateRecord:
+    MsiCloseHandle(hRecord);
+cleanup_CoInitialize:
+    if (bIsCoInitialized)
+    {
+        CoUninitialize();
+    }
+    return uiResult;
+}
+
+
+/**
+ * Schedules adapter creation.
+ *
+ * When the rollback is enabled, the adapter deletition is scheduled on rollback.
+ *
+ * @param seq           The argument sequence to pass to InstallTUNTAPAdapters custom action
+ *
+ * @param seqRollback   The argument sequence to pass to InstallTUNTAPAdaptersRollback custom
+ *                      action. NULL when rollback is disabled.
+ *
+ * @param szDisplayName  Adapter display name
+ *
+ * @param szHardwareId  Adapter hardware ID
+ *
+ * @param iTicks        Pointer to an integer that represents amount of work (on progress
+ *                      indicator) the InstallTUNTAPAdapters will take. This function increments it
+ *                      by MSICA_ADAPTER_TICK_SIZE for each adapter to create.
+ *
+ * @return ERROR_SUCCESS on success; An error code otherwise
+ */
+static DWORD
+schedule_adapter_create(
+    _Inout_ struct msica_arg_seq *seq,
+    _Inout_opt_ struct msica_arg_seq *seqRollback,
+    _In_z_ LPCTSTR szDisplayName,
+    _In_z_ LPCTSTR szHardwareId,
+    _Inout_ int *iTicks)
+{
+    /* Get existing network adapters. */
+    struct tap_adapter_node *pAdapterList = NULL;
+    DWORD dwResult = tap_list_adapters(NULL, NULL, &pAdapterList);
+    if (dwResult != ERROR_SUCCESS)
+    {
+        return dwResult;
+    }
+
+    /* Does adapter exist? */
+    for (struct tap_adapter_node *pAdapterOther = pAdapterList;; pAdapterOther = pAdapterOther->pNext)
+    {
+        if (pAdapterOther == NULL)
+        {
+            /* No adapter with a same name found. */
+            TCHAR szArgument[10 /*create=""|deleteN=""*/ + MAX_PATH /*szDisplayName*/ + 1 /*|*/ + MAX_PATH /*szHardwareId*/ + 1 /*terminator*/];
+
+            /* InstallTUNTAPAdapters will create the adapter. */
+            _stprintf_s(
+                szArgument, _countof(szArgument),
+                TEXT("create=\"%.*s|%.*s\""),
+                MAX_PATH, szDisplayName,
+                MAX_PATH, szHardwareId);
+            msica_arg_seq_add_tail(seq, szArgument);
+
+            if (seqRollback)
+            {
+                /* InstallTUNTAPAdaptersRollback will delete the adapter. */
+                _stprintf_s(
+                    szArgument, _countof(szArgument),
+                    TEXT("deleteN=\"%.*s\""),
+                    MAX_PATH, szDisplayName);
+                msica_arg_seq_add_head(seqRollback, szArgument);
+            }
+
+            *iTicks += MSICA_ADAPTER_TICK_SIZE;
+            break;
+        }
+        else if (_tcsicmp(szDisplayName, pAdapterOther->szName) == 0)
+        {
+            /* Adapter with a same name found. */
+            for (LPCTSTR hwid = pAdapterOther->szzHardwareIDs;; hwid += _tcslen(hwid) + 1)
+            {
+                if (hwid[0] == 0)
+                {
+                    /* This adapter has a different hardware ID. */
+                    msg(M_NONFATAL, "%s: Adapter with name \"%" PRIsLPTSTR "\" already exists", __FUNCTION__, pAdapterOther->szName);
+                    dwResult = ERROR_ALREADY_EXISTS;
+                    goto cleanup_pAdapterList;
+                }
+                else if (_tcsicmp(hwid, szHardwareId) == 0)
+                {
+                    /* This is an adapter with the requested hardware ID. We already have what we want! */
+                    break;
+                }
+            }
+            break; /* Adapter names are unique. There should be no other adapter with this name. */
+        }
+    }
+
+cleanup_pAdapterList:
+    tap_free_adapter_list(pAdapterList);
+    return dwResult;
+}
+
+
+/**
+ * Schedules adapter deletion.
+ *
+ * When the rollback is enabled, the adapter deletition is scheduled as: disable in
+ * UninstallTUNTAPAdapters, enable on rollback, delete on commit.
+ *
+ * When rollback is disabled, the adapter deletition is scheduled as delete in
+ * UninstallTUNTAPAdapters.
+ *
+ * @param seq           The argument sequence to pass to UninstallTUNTAPAdapters custom action
+ *
+ * @param seqCommit     The argument sequence to pass to UninstallTUNTAPAdaptersCommit custom
+ *                      action. NULL when rollback is disabled.
+ *
+ * @param seqRollback   The argument sequence to pass to UninstallTUNTAPAdaptersRollback custom
+ *                      action. NULL when rollback is disabled.
+ *
+ * @param szDisplayName  Adapter display name
+ *
+ * @param szzHardwareIDs  String of strings with acceptable adapter hardware IDs
+ *
+ * @param iTicks        Pointer to an integer that represents amount of work (on progress
+ *                      indicator) the UninstallTUNTAPAdapters will take. This function increments
+ *                      it by MSICA_ADAPTER_TICK_SIZE for each adapter to delete.
+ *
+ * @return ERROR_SUCCESS on success; An error code otherwise
+ */
+static DWORD
+schedule_adapter_delete(
+    _Inout_ struct msica_arg_seq *seq,
+    _Inout_opt_ struct msica_arg_seq *seqCommit,
+    _Inout_opt_ struct msica_arg_seq *seqRollback,
+    _In_z_ LPCTSTR szDisplayName,
+    _In_z_ LPCTSTR szzHardwareIDs,
+    _Inout_ int *iTicks)
+{
+    /* Get adapters with given hardware ID. */
+    struct tap_adapter_node *pAdapterList = NULL;
+    DWORD dwResult = tap_list_adapters(NULL, szzHardwareIDs, &pAdapterList);
+    if (dwResult != ERROR_SUCCESS)
+    {
+        return dwResult;
+    }
+
+    /* Does adapter exist? */
+    for (struct tap_adapter_node *pAdapter = pAdapterList; pAdapter != NULL; pAdapter = pAdapter->pNext)
+    {
+        if (_tcsicmp(szDisplayName, pAdapter->szName) == 0)
+        {
+            /* Adapter found. */
+            TCHAR szArgument[8 /*disable=|enable=|delete=*/ + 38 /*{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}*/ + 1 /*terminator*/];
+            if (seqCommit && seqRollback)
+            {
+                /* UninstallTUNTAPAdapters will disable the adapter. */
+                _stprintf_s(
+                    szArgument, _countof(szArgument),
+                    TEXT("disable=") TEXT(PRIXGUID),
+                    PRIGUID_PARAM(pAdapter->guid));
+                msica_arg_seq_add_tail(seq, szArgument);
+
+                /* UninstallTUNTAPAdaptersRollback will re-enable the adapter. */
+                _stprintf_s(
+                    szArgument, _countof(szArgument),
+                    TEXT("enable=") TEXT(PRIXGUID),
+                    PRIGUID_PARAM(pAdapter->guid));
+                msica_arg_seq_add_head(seqRollback, szArgument);
+
+                /* UninstallTUNTAPAdaptersCommit will delete the adapter. */
+                _stprintf_s(
+                    szArgument, _countof(szArgument),
+                    TEXT("delete=") TEXT(PRIXGUID),
+                    PRIGUID_PARAM(pAdapter->guid));
+                msica_arg_seq_add_tail(seqCommit, szArgument);
+            }
+            else
+            {
+                /* UninstallTUNTAPAdapters will delete the adapter. */
+                _stprintf_s(
+                    szArgument, _countof(szArgument),
+                    TEXT("delete=") TEXT(PRIXGUID),
+                    PRIGUID_PARAM(pAdapter->guid));
+                msica_arg_seq_add_tail(seq, szArgument);
+            }
+
+            iTicks += MSICA_ADAPTER_TICK_SIZE;
+            break; /* Adapter names are unique. There should be no other adapter with this name. */
+        }
+    }
+
+    tap_free_adapter_list(pAdapterList);
+    return dwResult;
+}
+
+
+UINT __stdcall
+EvaluateTUNTAPAdapters(_In_ MSIHANDLE hInstall)
+{
+#ifdef _MSC_VER
+#pragma comment(linker, DLLEXP_EXPORT)
+#endif
+
+    debug_popup(TEXT(__FUNCTION__));
+
+    UINT uiResult;
+    BOOL bIsCoInitialized = SUCCEEDED(CoInitialize(NULL));
+
+    OPENVPNMSICA_SAVE_MSI_SESSION(hInstall);
+
+    struct msica_arg_seq
+        seqInstall,
+        seqInstallCommit,
+        seqInstallRollback,
+        seqUninstall,
+        seqUninstallCommit,
+        seqUninstallRollback;
+    msica_arg_seq_init(&seqInstall);
+    msica_arg_seq_init(&seqInstallCommit);
+    msica_arg_seq_init(&seqInstallRollback);
+    msica_arg_seq_init(&seqUninstall);
+    msica_arg_seq_init(&seqUninstallCommit);
+    msica_arg_seq_init(&seqUninstallRollback);
+
+    /* Check rollback state. */
+    bool bRollbackEnabled = MsiEvaluateCondition(hInstall, TEXT("RollbackDisabled")) != MSICONDITION_TRUE;
+
+    /* Open MSI database. */
+    MSIHANDLE hDatabase = MsiGetActiveDatabase(hInstall);
+    if (hDatabase == 0)
+    {
+        msg(M_NONFATAL, "%s: MsiGetActiveDatabase failed", __FUNCTION__);
+        uiResult = ERROR_INVALID_HANDLE;
+        goto cleanup_exec_seq;
+    }
+
+    /* Check if TUNTAPAdapter table exists. If it doesn't exist, there's nothing to do. */
+    switch (MsiDatabaseIsTablePersistent(hDatabase, TEXT("TUNTAPAdapter")))
+    {
+        case MSICONDITION_FALSE:
+        case MSICONDITION_TRUE: break;
+
+        default:
+            uiResult = ERROR_SUCCESS;
+            goto cleanup_hDatabase;
+    }
+
+    /* Prepare a query to get a list/view of adapters. */
+    MSIHANDLE hViewST = 0;
+    LPCTSTR szQuery = TEXT("SELECT `Adapter`,`DisplayName`,`Condition`,`Component_`,`HardwareId` FROM `TUNTAPAdapter`");
+    uiResult = MsiDatabaseOpenView(hDatabase, szQuery, &hViewST);
+    if (uiResult != ERROR_SUCCESS)
+    {
+        SetLastError(uiResult); /* MSDN does not mention MsiDatabaseOpenView() to set GetLastError(). But we do have an error code. Set last error manually. */
+        msg(M_NONFATAL | M_ERRNO, "%s: MsiDatabaseOpenView(\"%" PRIsLPTSTR "\") failed", __FUNCTION__, szQuery);
+        goto cleanup_hDatabase;
+    }
+
+    /* Execute query! */
+    uiResult = MsiViewExecute(hViewST, 0);
+    if (uiResult != ERROR_SUCCESS)
+    {
+        SetLastError(uiResult); /* MSDN does not mention MsiViewExecute() to set GetLastError(). But we do have an error code. Set last error manually. */
+        msg(M_NONFATAL | M_ERRNO, "%s: MsiViewExecute(\"%" PRIsLPTSTR "\") failed", __FUNCTION__, szQuery);
+        goto cleanup_hViewST;
+    }
+
+    /* Create a record to report progress with. */
+    MSIHANDLE hRecordProg = MsiCreateRecord(2);
+    if (!hRecordProg)
+    {
+        uiResult = ERROR_INVALID_HANDLE;
+        msg(M_NONFATAL, "%s: MsiCreateRecord failed", __FUNCTION__);
+        goto cleanup_hViewST_close;
+    }
+
+    for (;; )
+    {
+        /* Fetch one record from the view. */
+        MSIHANDLE hRecord = 0;
+        uiResult = MsiViewFetch(hViewST, &hRecord);
+        if (uiResult == ERROR_NO_MORE_ITEMS)
+        {
+            uiResult = ERROR_SUCCESS;
+            break;
+        }
+        else if (uiResult != ERROR_SUCCESS)
+        {
+            SetLastError(uiResult); /* MSDN does not mention MsiViewFetch() to set GetLastError(). But we do have an error code. Set last error manually. */
+            msg(M_NONFATAL | M_ERRNO, "%s: MsiViewFetch failed", __FUNCTION__);
+            goto cleanup_hRecordProg;
+        }
+
+        INSTALLSTATE iInstalled, iAction;
+        {
+            /* Read adapter component ID (`Component_` is field #4). */
+            LPTSTR szValue = NULL;
+            uiResult = msi_get_record_string(hRecord, 4, &szValue);
+            if (uiResult != ERROR_SUCCESS)
+            {
+                goto cleanup_hRecord;
+            }
+
+            /* Get the component state. */
+            uiResult = MsiGetComponentState(hInstall, szValue, &iInstalled, &iAction);
+            if (uiResult != ERROR_SUCCESS)
+            {
+                SetLastError(uiResult); /* MSDN does not mention MsiGetComponentState() to set GetLastError(). But we do have an error code. Set last error manually. */
+                msg(M_NONFATAL | M_ERRNO, "%s: MsiGetComponentState(\"%" PRIsLPTSTR "\") failed", __FUNCTION__, szValue);
+                free(szValue);
+                goto cleanup_hRecord;
+            }
+            free(szValue);
+        }
+
+        /* Get adapter display name (`DisplayName` is field #2). */
+        LPTSTR szDisplayName = NULL;
+        uiResult = msi_format_field(hInstall, hRecord, 2, &szDisplayName);
+        if (uiResult != ERROR_SUCCESS)
+        {
+            goto cleanup_hRecord;
+        }
+        /* `DisplayName` field type is [Filename](https://docs.microsoft.com/en-us/windows/win32/msi/filename), which is either "8.3|long name" or "8.3". */
+        LPTSTR szDisplayNameEx = _tcschr(szDisplayName, TEXT('|'));
+        szDisplayNameEx = szDisplayNameEx != NULL ? szDisplayNameEx + 1 : szDisplayName;
+
+        /* Get adapter hardware ID (`HardwareId` is field #5). */
+        TCHAR szzHardwareIDs[0x100] = { 0 };
+        {
+            LPTSTR szHwId = NULL;
+            uiResult = msi_get_record_string(hRecord, 5, &szHwId);
+            if (uiResult != ERROR_SUCCESS)
+            {
+                goto cleanup_szDisplayName;
+            }
+            memcpy_s(szzHardwareIDs, sizeof(szzHardwareIDs) - 2*sizeof(TCHAR) /*requires double zero termination*/, szHwId, _tcslen(szHwId)*sizeof(TCHAR));
+            free(szHwId);
+        }
+
+        if (iAction > INSTALLSTATE_BROKEN)
+        {
+            int iTicks = 0;
+
+            if (iAction >= INSTALLSTATE_LOCAL)
+            {
+                /* Read and evaluate adapter condition (`Condition` is field #3). */
+                LPTSTR szValue = NULL;
+                uiResult = msi_get_record_string(hRecord, 3, &szValue);
+                if (uiResult != ERROR_SUCCESS)
+                {
+                    goto cleanup_szDisplayName;
+                }
+#ifdef __GNUC__
+/*
+ * warning: enumeration value ‘MSICONDITION_TRUE’ not handled in switch
+ * warning: enumeration value ‘MSICONDITION_NONE’ not handled in switch
+ */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wswitch"
+#endif
+                switch (MsiEvaluateCondition(hInstall, szValue))
+                {
+                    case MSICONDITION_FALSE:
+                        free(szValue);
+                        goto cleanup_szDisplayName;
+
+                    case MSICONDITION_ERROR:
+                        uiResult = ERROR_INVALID_FIELD;
+                        msg(M_NONFATAL | M_ERRNO, "%s: MsiEvaluateCondition(\"%" PRIsLPTSTR "\") failed", __FUNCTION__, szValue);
+                        free(szValue);
+                        goto cleanup_szDisplayName;
+                }
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
+                free(szValue);
+
+                /* Component is or should be installed. Schedule adapter creation. */
+                if (schedule_adapter_create(
+                        &seqInstall,
+                        bRollbackEnabled ? &seqInstallRollback : NULL,
+                        szDisplayNameEx,
+                        szzHardwareIDs,
+                        &iTicks) != ERROR_SUCCESS)
+                {
+                    uiResult = ERROR_INSTALL_FAILED;
+                    goto cleanup_szDisplayName;
+                }
+            }
+            else
+            {
+                /* Component is installed, but should be degraded to advertised/removed. Schedule adapter deletition.
+                 *
+                 * Note: On adapter removal (product is being uninstalled), we tolerate dwResult error.
+                 * Better a partial uninstallation than no uninstallation at all.
+                 */
+                schedule_adapter_delete(
+                    &seqUninstall,
+                    bRollbackEnabled ? &seqUninstallCommit : NULL,
+                    bRollbackEnabled ? &seqUninstallRollback : NULL,
+                    szDisplayNameEx,
+                    szzHardwareIDs,
+                    &iTicks);
+            }
+
+            /* Arrange the amount of tick space to add to the progress indicator.
+             * Do this within the loop to poll for user cancellation. */
+            MsiRecordSetInteger(hRecordProg, 1, 3 /* OP3 = Add ticks to the expected total number of progress of the progress bar */);
+            MsiRecordSetInteger(hRecordProg, 2, iTicks);
+            if (MsiProcessMessage(hInstall, INSTALLMESSAGE_PROGRESS, hRecordProg) == IDCANCEL)
+            {
+                uiResult = ERROR_INSTALL_USEREXIT;
+                goto cleanup_szDisplayName;
+            }
+        }
+
+cleanup_szDisplayName:
+        free(szDisplayName);
+cleanup_hRecord:
+        MsiCloseHandle(hRecord);
+        if (uiResult != ERROR_SUCCESS)
+        {
+            goto cleanup_hRecordProg;
+        }
+    }
+
+    /* Store deferred custom action parameters. */
+    if ((uiResult = setup_sequence(hInstall, TEXT("InstallTUNTAPAdapters"          ), &seqInstall          )) != ERROR_SUCCESS
+        || (uiResult = setup_sequence(hInstall, TEXT("InstallTUNTAPAdaptersCommit"    ), &seqInstallCommit    )) != ERROR_SUCCESS
+        || (uiResult = setup_sequence(hInstall, TEXT("InstallTUNTAPAdaptersRollback"  ), &seqInstallRollback  )) != ERROR_SUCCESS
+        || (uiResult = setup_sequence(hInstall, TEXT("UninstallTUNTAPAdapters"        ), &seqUninstall        )) != ERROR_SUCCESS
+        || (uiResult = setup_sequence(hInstall, TEXT("UninstallTUNTAPAdaptersCommit"  ), &seqUninstallCommit  )) != ERROR_SUCCESS
+        || (uiResult = setup_sequence(hInstall, TEXT("UninstallTUNTAPAdaptersRollback"), &seqUninstallRollback)) != ERROR_SUCCESS)
+    {
+        goto cleanup_hRecordProg;
+    }
+
+    uiResult = ERROR_SUCCESS;
+
+cleanup_hRecordProg:
+    MsiCloseHandle(hRecordProg);
+cleanup_hViewST_close:
+    MsiViewClose(hViewST);
+cleanup_hViewST:
+    MsiCloseHandle(hViewST);
+cleanup_hDatabase:
+    MsiCloseHandle(hDatabase);
+cleanup_exec_seq:
+    msica_arg_seq_free(&seqInstall);
+    msica_arg_seq_free(&seqInstallCommit);
+    msica_arg_seq_free(&seqInstallRollback);
+    msica_arg_seq_free(&seqUninstall);
+    msica_arg_seq_free(&seqUninstallCommit);
+    msica_arg_seq_free(&seqUninstallRollback);
+    if (bIsCoInitialized)
+    {
+        CoUninitialize();
+    }
+    return uiResult;
+}
+
+
+/**
+ * Parses string encoded GUID.
+ *
+ * @param szArg         Zero terminated string where the GUID string starts
+ *
+ * @param guid          Pointer to GUID that receives parsed value
+ *
+ * @return TRUE on success; FALSE otherwise
+ */
+static BOOL
+parse_guid(
+    _In_z_ LPCWSTR szArg,
+    _Out_ GUID *guid)
+{
+    if (swscanf_s(szArg, _L(PRIXGUID), PRIGUID_PARAM_REF(*guid)) != 11)
+    {
+        msg(M_NONFATAL | M_ERRNO, "%s: swscanf_s(\"%ls\") failed", __FUNCTION__, szArg);
+        return FALSE;
+    }
+    return TRUE;
+}
+
+
+UINT __stdcall
+ProcessDeferredAction(_In_ MSIHANDLE hInstall)
+{
+#ifdef _MSC_VER
+#pragma comment(linker, DLLEXP_EXPORT)
+#endif
+
+    debug_popup(TEXT(__FUNCTION__));
+
+    UINT uiResult;
+    BOOL bIsCoInitialized = SUCCEEDED(CoInitialize(NULL));
+
+    OPENVPNMSICA_SAVE_MSI_SESSION(hInstall);
+
+    BOOL bIsCleanup = MsiGetMode(hInstall, MSIRUNMODE_COMMIT) || MsiGetMode(hInstall, MSIRUNMODE_ROLLBACK);
+
+    /* Get sequence arguments. Always Unicode as CommandLineToArgvW() is available as Unicode-only. */
+    LPWSTR szSequence = NULL;
+    uiResult = msi_get_string(hInstall, L"CustomActionData", &szSequence);
+    if (uiResult != ERROR_SUCCESS)
+    {
+        goto cleanup_CoInitialize;
+    }
+    int nArgs;
+    LPWSTR *szArg = CommandLineToArgvW(szSequence, &nArgs);
+    if (szArg == NULL)
+    {
+        uiResult = GetLastError();
+        msg(M_NONFATAL | M_ERRNO, "%s: CommandLineToArgvW(\"%ls\") failed", __FUNCTION__, szSequence);
+        goto cleanup_szSequence;
+    }
+
+    /* Tell the installer to use explicit progress messages. */
+    MSIHANDLE hRecordProg = MsiCreateRecord(3);
+    MsiRecordSetInteger(hRecordProg, 1, 1);
+    MsiRecordSetInteger(hRecordProg, 2, 1);
+    MsiRecordSetInteger(hRecordProg, 3, 0);
+    MsiProcessMessage(hInstall, INSTALLMESSAGE_PROGRESS, hRecordProg);
+
+    /* Prepare hRecordProg for progress messages. */
+    MsiRecordSetInteger(hRecordProg, 1, 2);
+    MsiRecordSetInteger(hRecordProg, 3, 0);
+
+    BOOL bRebootRequired = FALSE;
+
+    for (int i = 1 /*CommandLineToArgvW injects msiexec.exe as szArg[0]*/; i < nArgs; ++i)
+    {
+        DWORD dwResult = ERROR_SUCCESS;
+
+        if (wcsncmp(szArg[i], L"create=", 7) == 0)
+        {
+            /* Create an adapter with a given name and hardware ID. */
+            LPWSTR szName = szArg[i] + 7;
+            LPWSTR szHardwareId = wcschr(szName, L'|');
+            if (szHardwareId == NULL)
+            {
+                goto invalid_argument;
+            }
+            szHardwareId[0] = 0;
+            ++szHardwareId;
+
+            {
+                /* Report the name of the adapter to installer. */
+                MSIHANDLE hRecord = MsiCreateRecord(4);
+                MsiRecordSetString(hRecord, 1, TEXT("Creating adapter"));
+                MsiRecordSetString(hRecord, 2, szName);
+                MsiRecordSetString(hRecord, 3, szHardwareId);
+                int iResult = MsiProcessMessage(hInstall, INSTALLMESSAGE_ACTIONDATA, hRecord);
+                MsiCloseHandle(hRecord);
+                if (iResult == IDCANCEL)
+                {
+                    uiResult = ERROR_INSTALL_USEREXIT;
+                    goto cleanup;
+                }
+            }
+
+            GUID guidAdapter;
+            dwResult = tap_create_adapter(NULL, NULL, szHardwareId, &bRebootRequired, &guidAdapter);
+            if (dwResult == ERROR_SUCCESS)
+            {
+                /* Set adapter name. */
+                dwResult = tap_set_adapter_name(&guidAdapter, szName);
+                if (dwResult != ERROR_SUCCESS)
+                {
+                    tap_delete_adapter(NULL, &guidAdapter, &bRebootRequired);
+                }
+            }
+        }
+        else if (wcsncmp(szArg[i], L"deleteN=", 8) == 0)
+        {
+            /* Delete the adapter by name. */
+            LPCWSTR szName = szArg[i] + 8;
+
+            {
+                /* Report the name of the adapter to installer. */
+                MSIHANDLE hRecord = MsiCreateRecord(3);
+                MsiRecordSetString(hRecord, 1, TEXT("Deleting adapter"));
+                MsiRecordSetString(hRecord, 2, szName);
+                int iResult = MsiProcessMessage(hInstall, INSTALLMESSAGE_ACTIONDATA, hRecord);
+                MsiCloseHandle(hRecord);
+                if (iResult == IDCANCEL)
+                {
+                    uiResult = ERROR_INSTALL_USEREXIT;
+                    goto cleanup;
+                }
+            }
+
+            /* Get existing adapters. */
+            struct tap_adapter_node *pAdapterList = NULL;
+            dwResult = tap_list_adapters(NULL, NULL, &pAdapterList);
+            if (dwResult == ERROR_SUCCESS)
+            {
+                /* Does the adapter exist? */
+                for (struct tap_adapter_node *pAdapter = pAdapterList; pAdapter != NULL; pAdapter = pAdapter->pNext)
+                {
+                    if (_tcsicmp(szName, pAdapter->szName) == 0)
+                    {
+                        /* Adapter found. */
+                        dwResult = tap_delete_adapter(NULL, &pAdapter->guid, &bRebootRequired);
+                        break;
+                    }
+                }
+
+                tap_free_adapter_list(pAdapterList);
+            }
+        }
+        else if (wcsncmp(szArg[i], L"delete=", 7) == 0)
+        {
+            /* Delete the adapter by GUID. */
+            GUID guid;
+            if (!parse_guid(szArg[i] + 7, &guid))
+            {
+                goto invalid_argument;
+            }
+            dwResult = tap_delete_adapter(NULL, &guid, &bRebootRequired);
+        }
+        else if (wcsncmp(szArg[i], L"enable=", 7) == 0)
+        {
+            /* Enable the adapter. */
+            GUID guid;
+            if (!parse_guid(szArg[i] + 7, &guid))
+            {
+                goto invalid_argument;
+            }
+            dwResult = tap_enable_adapter(NULL, &guid, TRUE, &bRebootRequired);
+        }
+        else if (wcsncmp(szArg[i], L"disable=", 8) == 0)
+        {
+            /* Disable the adapter. */
+            GUID guid;
+            if (!parse_guid(szArg[i] + 8, &guid))
+            {
+                goto invalid_argument;
+            }
+            dwResult = tap_enable_adapter(NULL, &guid, FALSE, &bRebootRequired);
+        }
+        else
+        {
+            goto invalid_argument;
+        }
+
+        if (dwResult != ERROR_SUCCESS && !bIsCleanup /* Ignore errors in case of commit/rollback to do as much work as possible. */)
+        {
+            uiResult = ERROR_INSTALL_FAILURE;
+            goto cleanup;
+        }
+
+        /* Report progress and check for user cancellation. */
+        MsiRecordSetInteger(hRecordProg, 2, MSICA_ADAPTER_TICK_SIZE);
+        if (MsiProcessMessage(hInstall, INSTALLMESSAGE_PROGRESS, hRecordProg) == IDCANCEL)
+        {
+            dwResult = ERROR_INSTALL_USEREXIT;
+            goto cleanup;
+        }
+
+        continue;
+
+invalid_argument:
+        msg(M_NONFATAL, "%s: Ignoring invalid argument: %ls", __FUNCTION__, szArg[i]);
+    }
+
+cleanup:
+    if (bRebootRequired)
+    {
+        MsiSetMode(hInstall, MSIRUNMODE_REBOOTATEND, TRUE);
+    }
+    MsiCloseHandle(hRecordProg);
+    LocalFree(szArg);
+cleanup_szSequence:
+    free(szSequence);
+cleanup_CoInitialize:
+    if (bIsCoInitialized)
+    {
+        CoUninitialize();
+    }
+    return uiResult;
+}
diff --git a/src/openvpnmsica/openvpnmsica.h b/src/openvpnmsica/openvpnmsica.h
new file mode 100644
index 0000000..221d03c
--- /dev/null
+++ b/src/openvpnmsica/openvpnmsica.h
@@ -0,0 +1,153 @@
+/*
+ *  openvpnmsica -- Custom Action DLL to provide OpenVPN-specific support to MSI packages
+ *                  https://community.openvpn.net/openvpn/wiki/OpenVPNMSICA
+ *
+ *  Copyright (C) 2018 Simon Rozman <simon@rozman.si>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MSICA_H
+#define MSICA_H
+
+#include <windows.h>
+#include <msi.h>
+#include "../tapctl/basic.h"
+
+
+/*
+ * Error codes (next unused 2552L)
+ */
+#define ERROR_MSICA       2550L
+#define ERROR_MSICA_ERRNO 2551L
+
+
+/**
+ * Thread local storage data
+ */
+struct openvpnmsica_thread_data
+{
+    MSIHANDLE hInstall; /** Handle to the installation session. */
+};
+
+
+/**
+ * MSI session handle thread local storage index
+ */
+extern DWORD openvpnmsica_thread_data_idx;
+
+
+/**
+ * Set MSI session handle in thread local storage.
+ */
+#define OPENVPNMSICA_SAVE_MSI_SESSION(hInstall) \
+{ \
+    struct openvpnmsica_thread_data *s = (struct openvpnmsica_thread_data *)TlsGetValue(openvpnmsica_thread_data_idx); \
+    s->hInstall = (hInstall); \
+}
+
+
+/*
+ * Exported DLL Functions
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __GNUC__
+#define DLLEXP_DECL __declspec(dllexport)
+#else
+#define DLLEXP_DECL
+#define DLLEXP_EXPORT "/EXPORT:" __FUNCTION__ "=" __FUNCDNAME__
+#endif
+
+
+/**
+ * Determines Windows information:
+ *
+ * - Sets `OPENVPNSERVICE` MSI property to PID of OpenVPN Service if running, or its EXE path if
+ *   configured for auto-start.
+ *
+ * - Finds existing TAP-Windows6 adapters and set TAPWINDOWS6ADAPTERS and
+ *   ACTIVETAPWINDOWS6ADAPTERS properties with semicolon delimited list of all installed adapter
+ *   GUIDs and active adapter GUIDs respectively.
+ *
+ * - Finds existing Wintun adapters and set WINTUNADAPTERS and ACTIVEWINTUNADAPTERS properties
+ *   with semicolon delimited list of all installed adapter GUIDs and active adapter GUIDs
+ *   respectively.
+ *
+ * @param hInstall      Handle to the installation provided to the DLL custom action
+ *
+ * @return ERROR_SUCCESS on success; An error code otherwise
+ *         See: https://msdn.microsoft.com/en-us/library/windows/desktop/aa368072.aspx
+ */
+DLLEXP_DECL UINT __stdcall
+FindSystemInfo(_In_ MSIHANDLE hInstall);
+
+
+/**
+ * Find OpenVPN GUI window and send it a WM_CLOSE message.
+ *
+ * @param hInstall      Handle to the installation provided to the DLL custom action
+ *
+ * @return ERROR_SUCCESS on success; An error code otherwise
+ *         See: https://msdn.microsoft.com/en-us/library/windows/desktop/aa368072.aspx
+ */
+DLLEXP_DECL UINT __stdcall
+CloseOpenVPNGUI(_In_ MSIHANDLE hInstall);
+
+
+/**
+ * Launches OpenVPN GUI. It's path is obtained by expanding the `[#bin.openvpn_gui.exe]`
+ * therefore, its Id field in File table must be "bin.openvpn_gui.exe".
+ *
+ * @param hInstall      Handle to the installation provided to the DLL custom action
+ *
+ * @return ERROR_SUCCESS on success; An error code otherwise
+ *         See: https://msdn.microsoft.com/en-us/library/windows/desktop/aa368072.aspx
+ */
+DLLEXP_DECL UINT __stdcall
+StartOpenVPNGUI(_In_ MSIHANDLE hInstall);
+
+
+/**
+ * Evaluate the TUNTAPAdapter table of the MSI package database and prepare a list of TAP
+ * adapters to install/remove.
+ *
+ * @param hInstall      Handle to the installation provided to the DLL custom action
+ *
+ * @return ERROR_SUCCESS on success; An error code otherwise
+ *         See: https://msdn.microsoft.com/en-us/library/windows/desktop/aa368072.aspx
+ */
+DLLEXP_DECL UINT __stdcall
+EvaluateTUNTAPAdapters(_In_ MSIHANDLE hInstall);
+
+
+/**
+ * Perform scheduled deferred action.
+ *
+ * @param hInstall      Handle to the installation provided to the DLL custom action
+ *
+ * @return ERROR_SUCCESS on success; An error code otherwise
+ *         See: https://msdn.microsoft.com/en-us/library/windows/desktop/aa368072.aspx
+ */
+DLLEXP_DECL UINT __stdcall
+ProcessDeferredAction(_In_ MSIHANDLE hInstall);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ifndef MSICA_H */
diff --git a/src/openvpnmsica/openvpnmsica.props b/src/openvpnmsica/openvpnmsica.props
new file mode 100644
index 0000000..074635d
--- /dev/null
+++ b/src/openvpnmsica/openvpnmsica.props
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ImportGroup Label="PropertySheets" />
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup>
+    <TargetName>lib$(ProjectName)</TargetName>
+  </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <AdditionalIncludeDirectories>..\compat;$(TAP_WINDOWS_HOME)/include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <PreprocessorDefinitions>_WIN32_WINNT=_WIN32_WINNT_VISTA;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Windows</SubSystem>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemGroup />
+</Project>
\ No newline at end of file
diff --git a/src/openvpnmsica/openvpnmsica.vcxproj b/src/openvpnmsica/openvpnmsica.vcxproj
new file mode 100644
index 0000000..4b42980
--- /dev/null
+++ b/src/openvpnmsica/openvpnmsica.vcxproj
@@ -0,0 +1,142 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|ARM64">
+      <Configuration>Debug</Configuration>
+      <Platform>ARM64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|ARM64">
+      <Configuration>Release</Configuration>
+      <Platform>ARM64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <VCProjectVersion>15.0</VCProjectVersion>
+    <ProjectGuid>{D41AA9D6-B818-476E-992E-0E16EB86BEE2}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>openvpnmsica</RootNamespace>
+    <WindowsTargetPlatformVersion>10.0</WindowsTargetPlatformVersion>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v142</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+    <WindowsSDKDesktopARM64Support>true</WindowsSDKDesktopARM64Support>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v142</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v142</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>v142</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+    <WindowsSDKDesktopARM64Support>true</WindowsSDKDesktopARM64Support>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>v142</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>v142</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="Shared">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+    <Import Project="..\compat\Debug.props" />
+    <Import Project="openvpnmsica-Debug.props" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+    <Import Project="..\compat\Debug.props" />
+    <Import Project="openvpnmsica-Debug.props" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+    <Import Project="..\compat\Debug.props" />
+    <Import Project="openvpnmsica-Debug.props" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+    <Import Project="..\compat\Release.props" />
+    <Import Project="openvpnmsica-Release.props" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+    <Import Project="..\compat\Release.props" />
+    <Import Project="openvpnmsica-Release.props" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+    <Import Project="..\compat\Release.props" />
+    <Import Project="openvpnmsica-Release.props" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <ItemGroup>
+    <ClCompile Include="..\tapctl\error.c" />
+    <ClCompile Include="..\tapctl\tap.c" />
+    <ClCompile Include="dllmain.c" />
+    <ClCompile Include="msiex.c" />
+    <ClCompile Include="msica_arg.c" />
+    <ClCompile Include="openvpnmsica.c" />
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="..\tapctl\basic.h" />
+    <ClInclude Include="..\tapctl\error.h" />
+    <ClInclude Include="..\tapctl\tap.h" />
+    <ClInclude Include="msiex.h" />
+    <ClInclude Include="msica_arg.h" />
+    <ClInclude Include="openvpnmsica.h" />
+  </ItemGroup>
+  <ItemGroup>
+    <ResourceCompile Include="openvpnmsica_resources.rc" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\build\msvc\msvc-generate\msvc-generate.vcxproj">
+      <Project>{8598c2c8-34c4-47a1-99b0-7c295a890615}</Project>
+      <ReferenceOutputAssembly>false</ReferenceOutputAssembly>
+    </ProjectReference>
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
\ No newline at end of file
diff --git a/src/openvpnmsica/openvpnmsica.vcxproj.filters b/src/openvpnmsica/openvpnmsica.vcxproj.filters
new file mode 100644
index 0000000..cb050f9
--- /dev/null
+++ b/src/openvpnmsica/openvpnmsica.vcxproj.filters
@@ -0,0 +1,62 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <Filter Include="Source Files">
+      <UniqueIdentifier>{4FC737F1-C7A5-4376-A066-2A32D752A2FF}</UniqueIdentifier>
+      <Extensions>cpp;c;cc;cxx;def;odl;idl;hpj;bat;asm;asmx</Extensions>
+    </Filter>
+    <Filter Include="Header Files">
+      <UniqueIdentifier>{93995380-89BD-4b04-88EB-625FBE52EBFB}</UniqueIdentifier>
+      <Extensions>h;hh;hpp;hxx;hm;inl;inc;xsd</Extensions>
+    </Filter>
+    <Filter Include="Resource Files">
+      <UniqueIdentifier>{67DA6AB6-F800-4c08-8B7A-83BB121AAD01}</UniqueIdentifier>
+      <Extensions>rc;ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe;resx;tiff;tif;png;wav;mfcribbon-ms</Extensions>
+    </Filter>
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="dllmain.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\tapctl\error.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="msiex.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="openvpnmsica.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="msica_arg.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\tapctl\tap.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="openvpnmsica.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="msiex.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="msica_arg.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="..\tapctl\tap.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="..\tapctl\error.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="..\tapctl\basic.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+  </ItemGroup>
+  <ItemGroup>
+    <ResourceCompile Include="openvpnmsica_resources.rc">
+      <Filter>Resource Files</Filter>
+    </ResourceCompile>
+  </ItemGroup>
+</Project>
\ No newline at end of file
diff --git a/src/openvpnmsica/openvpnmsica_resources.rc b/src/openvpnmsica/openvpnmsica_resources.rc
new file mode 100644
index 0000000..1859fc3
--- /dev/null
+++ b/src/openvpnmsica/openvpnmsica_resources.rc
@@ -0,0 +1,62 @@
+/*
+ *  openvpnmsica -- Custom Action DLL to provide OpenVPN-specific support to MSI packages
+ *
+ *  Copyright (C) 2018 Simon Rozman <simon@rozman.si>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#else
+#include <config-msvc-version.h>
+#endif
+#include <winresrc.h>
+
+#pragma code_page(65001) /* UTF8 */
+
+LANGUAGE LANG_NEUTRAL, SUBLANG_NEUTRAL
+
+VS_VERSION_INFO VERSIONINFO
+    FILEVERSION OPENVPN_VERSION_RESOURCE
+    PRODUCTVERSION OPENVPN_VERSION_RESOURCE
+    FILEFLAGSMASK VS_FF_DEBUG | VS_FF_PRERELEASE | VS_FF_PATCHED | VS_FF_PRIVATEBUILD | VS_FF_SPECIALBUILD
+#ifdef _DEBUG
+    FILEFLAGS VS_FF_DEBUG
+#else
+    FILEFLAGS 0x0L
+#endif
+    FILEOS VOS_NT_WINDOWS32
+    FILETYPE VFT_DLL
+    FILESUBTYPE 0x0L
+BEGIN
+    BLOCK "StringFileInfo"
+    BEGIN
+        BLOCK "040904b0"
+        BEGIN
+            VALUE "CompanyName", "The OpenVPN Project"
+            VALUE "FileDescription", "Custom Action DLL to provide OpenVPN-specific support to MSI packages"
+            VALUE "FileVersion", PACKAGE_VERSION ".0"
+            VALUE "InternalName", "OpenVPN"
+            VALUE "LegalCopyright", "Copyright © The OpenVPN Project"
+            VALUE "OriginalFilename", "libopenvpnmsica.dll"
+            VALUE "ProductName", "OpenVPN"
+            VALUE "ProductVersion", PACKAGE_VERSION ".0"
+        END
+    END
+    BLOCK "VarFileInfo"
+    BEGIN
+        VALUE "Translation", 0x409, 1200
+    END
+END