configure.ac

dnl  OpenVPN -- An application to securely tunnel IP networks
dnl             over a single UDP port, with support for SSL/TLS-based
dnl             session authentication and key exchange,
dnl             packet encryption, packet authentication, and
dnl             packet compression.
dnl
dnl  Copyright (C) 2002-2024 OpenVPN Inc <sales@openvpn.net>
dnl  Copyright (C) 2006-2012 Alon Bar-Lev <alon.barlev@gmail.com>
dnl
dnl  This program is free software; you can redistribute it and/or modify
dnl  it under the terms of the GNU General Public License as published by
dnl  the Free Software Foundation; either version 2 of the License, or
dnl  (at your option) any later version.
dnl
dnl  This program is distributed in the hope that it will be useful,
dnl  but WITHOUT ANY WARRANTY; without even the implied warranty of
dnl  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
dnl  GNU General Public License for more details.
dnl
dnl  You should have received a copy of the GNU General Public License along
dnl  with this program; if not, write to the Free Software Foundation, Inc.,
dnl  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

dnl Process this file with autoconf to produce a configure script.

AC_PREREQ(2.60)

m4_include(version.m4)
AC_INIT([PRODUCT_NAME], [PRODUCT_VERSION], [PRODUCT_BUGREPORT], [PRODUCT_TARNAME])
m4_include(compat.m4)
AC_DEFINE([OPENVPN_VERSION_RESOURCE], [PRODUCT_VERSION_RESOURCE], [Version in windows resource format])
AC_SUBST([OPENVPN_VERSION_MAJOR], [PRODUCT_VERSION_MAJOR], [OpenVPN major version])
AC_SUBST([OPENVPN_VERSION_MINOR], [PRODUCT_VERSION_MINOR], [OpenVPN minor version])
AC_SUBST([OPENVPN_VERSION_PATCH], [PRODUCT_VERSION_PATCH], [OpenVPN patch level - may be a string or integer])
AC_DEFINE([OPENVPN_VERSION_MAJOR], [PRODUCT_VERSION_MAJOR], [OpenVPN major version - integer])
AC_DEFINE([OPENVPN_VERSION_MINOR], [PRODUCT_VERSION_MINOR], [OpenVPN minor version - integer])
AC_DEFINE([OPENVPN_VERSION_PATCH], ["PRODUCT_VERSION_PATCH"], [OpenVPN patch level - may be a string or integer])

AC_CONFIG_AUX_DIR([.])
AC_CONFIG_HEADERS([config.h include/openvpn-plugin.h])
AC_CONFIG_SRCDIR([src/openvpn/syshead.h])
AC_CONFIG_MACRO_DIR([m4])

dnl Automake 1.14+ warns if sources are in sub-directories but subdir-objects
dnl options is not enabled. However, automake before 1.15a has a bug that causes
dnl variable expansion to fail in foo_SOURCES when this option is used.
dnl As most of our build systems are now likely to use automake 1.16+ add a
dnl work around to conditionally add subdir-objects option.
m4_define([subdir_objects], [
    m4_esyscmd([automake --version |
                head -1 |
                awk '{split ($NF,a,"."); if (a[1] == 1 && a[2] >= 16) { print "subdir-objects" }}'
    ])
])

# This foreign option prevents autoreconf from overriding our COPYING and
# INSTALL targets:
AM_INIT_AUTOMAKE(foreign subdir_objects 1.9) dnl NB: Do not [quote] this parameter.
AM_SILENT_RULES([yes])
AC_CANONICAL_HOST
AC_USE_SYSTEM_EXTENSIONS

AC_ARG_ENABLE(
	[lzo],
	[AS_HELP_STRING([--disable-lzo], [disable LZO compression support @<:@default=yes@:>@])],
	,
	[enable_lzo="yes"]
)

AC_ARG_ENABLE(
	[lz4],
	[AS_HELP_STRING([--disable-lz4], [disable LZ4 compression support @<:@default=yes@:>@])],
	[enable_lz4="$enableval"],
	[enable_lz4="yes"]
)

AC_ARG_ENABLE(
	[comp-stub],
	[AS_HELP_STRING([--enable-comp-stub], [disable compression support but still allow limited interoperability with compression-enabled peers @<:@default=no@:>@])],
	[enable_comp_stub="$enableval"],
	[enable_comp_stub="no"]
)

AC_ARG_ENABLE(
	[ofb-cfb],
	[AS_HELP_STRING([--disable-ofb-cfb], [disable support for OFB and CFB cipher modes @<:@default=yes@:>@])],
	,
	[enable_crypto_ofb_cfb="yes"]
)

AC_ARG_ENABLE(
	[x509-alt-username],
	[AS_HELP_STRING([--enable-x509-alt-username], [enable the --x509-username-field feature @<:@default=no@:>@])],
	,
	[enable_x509_alt_username="no"]
)

AC_ARG_ENABLE(
	[ntlm],
	[AS_HELP_STRING([--disable-ntlm], [disable NTLMv2 proxy support @<:@default=yes@:>@])],
	,
	[enable_ntlm="yes"]
)

AC_ARG_ENABLE(
	[plugins],
	[AS_HELP_STRING([--disable-plugins], [disable plug-in support @<:@default=yes@:>@])],
	,
	[enable_plugins="yes"]
)

AC_ARG_ENABLE(
	[management],
	[AS_HELP_STRING([--disable-management], [disable management server support @<:@default=yes@:>@])],
	,
	[enable_management="yes"]
)

AC_ARG_ENABLE(
	[pkcs11],
	[AS_HELP_STRING([--enable-pkcs11], [enable pkcs11 support @<:@default=no@:>@])],
	,
	[enable_pkcs11="no"]
)

AC_ARG_ENABLE(
	[fragment],
	[AS_HELP_STRING([--disable-fragment], [disable internal fragmentation support (--fragment) @<:@default=yes@:>@])],
	,
	[enable_fragment="yes"]
)

AC_ARG_ENABLE(
	[port-share],
	[AS_HELP_STRING([--disable-port-share], [disable TCP server port-share support (--port-share) @<:@default=yes@:>@])],
	,
	[enable_port_share="yes"]
)

AC_ARG_ENABLE(
	[debug],
	[AS_HELP_STRING([--disable-debug], [disable debugging support (disable gremlin and verb 7+ messages) @<:@default=yes@:>@])],
	,
	[enable_debug="yes"]
)

AC_ARG_ENABLE(
	[small],
	[AS_HELP_STRING([--enable-small], [enable smaller executable size (disable OCC, usage message, and verb 4 parm list) @<:@default=no@:>@])],
	,
	[enable_small="no"]
)

AC_ARG_ENABLE(
	[dco],
	[AS_HELP_STRING([--disable-dco], [disable data channel offload support using the ovpn-dco kernel module @<:@default=yes@:>@ on Linux/FreeBSD, can't disable on Windows])],
	,
	[
		case "$host" in
			*-*-linux*)
				enable_dco="auto"
			;;
			*-*-freebsd*)
				enable_dco="auto"
			;;
			*)
				# note that this does not disable it for Windows
				enable_dco="no"
			;;
		esac
	]
)

AC_ARG_ENABLE(
	[iproute2],
	[AS_HELP_STRING([--enable-iproute2], [enable support for iproute2 (disables DCO) @<:@default=no@:>@])],
	,
	[enable_iproute2="no"]
)

AC_ARG_ENABLE(
	[plugin-auth-pam],
	[AS_HELP_STRING([--disable-plugin-auth-pam], [disable auth-pam plugin @<:@default=platform specific@:>@])],
	,
	[
		case "$host" in
			*-*-openbsd*) enable_plugin_auth_pam="no";;
			*-mingw*) enable_plugin_auth_pam="no";;
			*) enable_plugin_auth_pam="yes";;
		esac
	]
)

AC_ARG_ENABLE(
	[plugin-down-root],
	[AS_HELP_STRING([--disable-plugin-down-root], [disable down-root plugin @<:@default=platform specific@:>@])],
	,
	[
		case "$host" in
			*-mingw*) enable_plugin_down_root="no";;
			*) enable_plugin_down_root="yes";;
		esac
	]
)

AC_ARG_ENABLE(
	[pam-dlopen],
	[AS_HELP_STRING([--enable-pam-dlopen], [dlopen libpam @<:@default=no@:>@])],
	,
	[enable_pam_dlopen="no"]
)

AC_ARG_ENABLE(
	[strict],
	[AS_HELP_STRING([--enable-strict], [enable strict compiler warnings (debugging option) @<:@default=no@:>@])],
	,
	[enable_strict="no"]
)

AC_ARG_ENABLE(
	[pedantic],
	[AS_HELP_STRING([--enable-pedantic], [enable pedantic compiler warnings, will not generate a working executable (debugging option) @<:@default=no@:>@])],
	,
	[enable_pedantic="no"]
)

AC_ARG_ENABLE(
	[werror],
	[AS_HELP_STRING([--enable-werror], [promote compiler warnings to errors, will cause builds to fail if the compiler issues warnings (debugging option) @<:@default=no@:>@])],
	,
	[enable_werror="no"]
)

AC_ARG_ENABLE(
	[strict-options],
	[AS_HELP_STRING([--enable-strict-options], [enable strict options check between peers (debugging option) @<:@default=no@:>@])],
	,
	[enable_strict_options="no"]
)

AC_ARG_ENABLE(
	[selinux],
	[AS_HELP_STRING([--enable-selinux], [enable SELinux support @<:@default=no@:>@])],
	,
	[enable_selinux="no"]
)

AC_ARG_ENABLE(
	[systemd],
	[AS_HELP_STRING([--enable-systemd], [enable systemd support @<:@default=no@:>@])],
	,
	[enable_systemd="no"]
)

AC_ARG_ENABLE(
	[async-push],
	[AS_HELP_STRING([--enable-async-push], [enable async-push support for plugins providing deferred authentication @<:@default=no@:>@])],
	,
	[enable_async_push="no"]
)

AC_ARG_WITH(
	[special-build],
	[AS_HELP_STRING([--with-special-build=STRING], [specify special build string])],
	[test -n "${withval}" && AC_DEFINE_UNQUOTED([CONFIGURE_SPECIAL_BUILD], ["${withval}"], [special build string])]
)

AC_ARG_WITH(
	[mem-check],
	[AS_HELP_STRING([--with-mem-check=TYPE], [build with debug memory checking, TYPE=no|dmalloc|valgrind|ssl @<:@default=no@:>@])],
	[
		case "${withval}" in
			dmalloc|valgrind|ssl|no) ;;
			*) AC_MSG_ERROR([bad value ${withval} for --mem-check]) ;;
		esac
	],
	[with_mem_check="no"]
)

AC_ARG_WITH(
	[crypto-library],
	[AS_HELP_STRING([--with-crypto-library=library], [build with the given crypto library, TYPE=openssl|mbedtls|wolfssl @<:@default=openssl@:>@])],
	[
		case "${withval}" in
			openssl|mbedtls|wolfssl) ;;
			*) AC_MSG_ERROR([bad value ${withval} for --with-crypto-library]) ;;
		esac
	],
	[with_crypto_library="openssl"]
)

AC_ARG_ENABLE(
	[wolfssl-options-h],
	[AS_HELP_STRING([--disable-wolfssl-options-h], [Disable including options.h in wolfSSL @<:@default=yes@:>@])],
	,
	[enable_wolfssl_options_h="yes"]
)

AC_ARG_WITH(
	[openssl-engine],
	[AS_HELP_STRING([--with-openssl-engine], [enable engine support with OpenSSL. Default enabled for OpenSSL < 3.0, auto,yes,no @<:@default=auto@:>@])],
	[
		case "${withval}" in
			auto|yes|no) ;;
			*) AC_MSG_ERROR([bad value ${withval} for --with-engine]) ;;
		esac
	],
	[with_openssl_engine="auto"]
)

AC_ARG_VAR([PLUGINDIR], [Path of plug-in directory @<:@default=LIBDIR/openvpn/plugins@:>@])
if test -n "${PLUGINDIR}"; then
	plugindir="${PLUGINDIR}"
else
	plugindir="\${libdir}/openvpn/plugins"
fi

AC_DEFINE_UNQUOTED([TARGET_ALIAS], ["${host}"], [A string representing our host])
AM_CONDITIONAL([TARGET_LINUX], [false])
case "$host" in
	*-*-linux*)
		AC_DEFINE([TARGET_LINUX], [1], [Are we running on Linux?])
		AM_CONDITIONAL([TARGET_LINUX], [true])
		AC_DEFINE_UNQUOTED([TARGET_PREFIX], ["L"], [Target prefix])
		have_sitnl="yes"
		pkg_config_required="yes"
		;;
	*-*-solaris*)
		AC_DEFINE([TARGET_SOLARIS], [1], [Are we running on Solaris?])
		AC_DEFINE_UNQUOTED([TARGET_PREFIX], ["S"], [Target prefix])
		CPPFLAGS="$CPPFLAGS -D_XPG4_2"
		test -x /bin/bash && SHELL="/bin/bash"
		;;
	*-*-openbsd*)
		AC_DEFINE([TARGET_OPENBSD], [1], [Are we running on OpenBSD?])
		AC_DEFINE_UNQUOTED([TARGET_PREFIX], ["O"], [Target prefix])
		;;
	*-*-freebsd*)
		AC_DEFINE([TARGET_FREEBSD], [1], [Are we running on FreeBSD?])
		AC_DEFINE_UNQUOTED([TARGET_PREFIX], ["F"], [Target prefix])
		;;
	*-*-netbsd*)
		AC_DEFINE([TARGET_NETBSD], [1], [Are we running NetBSD?])
		AC_DEFINE_UNQUOTED([TARGET_PREFIX], ["N"], [Target prefix])
		;;
	*-*-darwin*)
		AC_DEFINE([TARGET_DARWIN], [1], [Are we running on Mac OS X?])
		AC_DEFINE_UNQUOTED([TARGET_PREFIX], ["M"], [Target prefix])
		have_tap_header="yes"
		ac_cv_type_struct_in_pktinfo=no
		;;
	*-mingw*)
		AC_DEFINE([TARGET_WIN32], [1], [Are we running WIN32?])
		AC_DEFINE([ENABLE_DCO], [1], [DCO is always enabled on Windows])
		AC_DEFINE_UNQUOTED([TARGET_PREFIX], ["W"], [Target prefix])
		CPPFLAGS="${CPPFLAGS} -DWIN32_LEAN_AND_MEAN"
		CPPFLAGS="${CPPFLAGS} -DNTDDI_VERSION=NTDDI_VISTA -D_WIN32_WINNT=_WIN32_WINNT_VISTA"
		WIN32=yes
		;;
	*-*-dragonfly*)
		AC_DEFINE([TARGET_DRAGONFLY], [1], [Are we running on DragonFlyBSD?])
		AC_DEFINE_UNQUOTED([TARGET_PREFIX], ["D"], [Target prefix])
		;;
	*-aix*)
		AC_DEFINE([TARGET_AIX], [1], [Are we running AIX?])
		AC_DEFINE_UNQUOTED([TARGET_PREFIX], ["A"], [Target prefix])
		ROUTE="/usr/sbin/route"
		have_tap_header="yes"
		ac_cv_header_net_if_h="no"	# exists, but breaks things
		;;
	*-*-haiku*)
		AC_DEFINE([TARGET_HAIKU], [1], [Are we running Haiku?])
		AC_DEFINE_UNQUOTED([TARGET_PREFIX], ["H"], [Target prefix])
		LIBS="${LIBS} -lnetwork"
		;;
	*)
		AC_DEFINE_UNQUOTED([TARGET_PREFIX], ["X"], [Target prefix])
		have_tap_header="yes"
		;;
esac

AM_CONDITIONAL([CROSS_COMPILING], test "${cross_compiling}" = "yes")

PKG_PROG_PKG_CONFIG
# Add variable to print if pkg-config is found or not. Users often miss that
if test "${PKG_CONFIG}" = ""; then
	if test "${pkg_config_required}" = "yes"; then
		AC_MSG_ERROR([pkg-config is required])
	fi
	pkg_config_found="(not found)"
else
	pkg_config_found="(${PKG_CONFIG})"
fi

AC_PROG_CC
AC_PROG_CPP
AC_PROG_INSTALL
AC_PROG_LN_S
AC_PROG_SED
AC_PROG_MAKE_SET

AC_ARG_VAR([IFCONFIG], [full path to ipconfig utility])
AC_ARG_VAR([ROUTE], [full path to route utility])
AC_ARG_VAR([IPROUTE], [full path to ip utility])
AC_ARG_VAR([NETSTAT], [path to netstat utility]) # tests
AC_ARG_VAR([GIT], [path to git utility])
AC_ARG_VAR([SYSTEMD_ASK_PASSWORD], [path to systemd-ask-password utility])
AC_ARG_VAR([SYSTEMD_UNIT_DIR], [Path of systemd unit directory @<:@default=LIBDIR/systemd/system@:>@])
AC_ARG_VAR([TMPFILES_DIR], [Path of tmpfiles directory @<:@default=LIBDIR/tmpfiles.d@:>@])
AC_PATH_PROGS([IFCONFIG], [ifconfig],, [$PATH:/usr/local/sbin:/usr/sbin:/sbin])
AC_PATH_PROGS([ROUTE], [route],, [$PATH:/usr/local/sbin:/usr/sbin:/sbin])
AC_PATH_PROGS([IPROUTE], [ip],, [$PATH:/usr/local/sbin:/usr/sbin:/sbin])
AC_PATH_PROGS([SYSTEMD_ASK_PASSWORD], [systemd-ask-password],, [$PATH:/usr/local/bin:/usr/bin:/bin])
AC_CHECK_PROGS([NETSTAT], [netstat], [netstat], [$PATH:/usr/local/sbin:/usr/sbin:/sbin:/etc]) # tests
AC_CHECK_PROGS([GIT], [git]) # optional
AC_DEFINE_UNQUOTED([IFCONFIG_PATH], ["$IFCONFIG"], [Path to ifconfig tool])
AC_DEFINE_UNQUOTED([IPROUTE_PATH], ["$IPROUTE"], [Path to iproute tool])
AC_DEFINE_UNQUOTED([ROUTE_PATH], ["$ROUTE"], [Path to route tool])
AC_DEFINE_UNQUOTED([SYSTEMD_ASK_PASSWORD_PATH], ["$SYSTEMD_ASK_PASSWORD"], [Path to systemd-ask-password tool])

#
#  man page generation - based on python-docutils
#
AC_ARG_VAR([RST2MAN], [path to rst2man utility])
AC_ARG_VAR([RST2HTML], [path to rst2html utility])
AC_CHECK_PROGS([RST2MAN], [rst2man rst2man.py])
AC_CHECK_PROGS([RST2HTML], [rst2html rst2html.py])
AM_CONDITIONAL([HAVE_PYDOCUTILS], [test "${RST2MAN}" -a "${RST2HTML}"])

# Set -std=c11 unless user already specified a -std=
case "${CFLAGS}" in
  *-std=*) ;;
  *)       CFLAGS="${CFLAGS} -std=c11" ;;
esac

#
# Libtool
#
ifdef(
	[LT_INIT],
	[
		LT_INIT([win32-dll])
		LT_LANG([Windows Resource])
	],
	[
		AC_LIBTOOL_WIN32_DLL
		AC_LIBTOOL_RC
		AC_PROG_LIBTOOL
	]
)

AC_C_INLINE
AC_TYPE_OFF_T
AC_TYPE_PID_T
AC_TYPE_SIZE_T
AC_TYPE_UID_T
AX_TYPE_SOCKLEN_T
AC_CHECK_SIZEOF([unsigned int])
AC_CHECK_SIZEOF([unsigned long])
AC_CHECK_HEADERS([ \
	fcntl.h io.h \
	sys/types.h sys/socket.h \
	unistd.h dlfcn.h \
	netinet/in.h \
	netinet/tcp.h arpa/inet.h netdb.h \
])
AC_CHECK_HEADERS([ \
	sys/time.h sys/ioctl.h sys/stat.h \
	sys/mman.h sys/file.h sys/wait.h \
	unistd.h libgen.h stropts.h \
	syslog.h pwd.h grp.h termios.h \
	sys/sockio.h sys/uio.h linux/sockios.h \
	linux/types.h linux/errqueue.h poll.h sys/epoll.h err.h \
])

SOCKET_INCLUDES="
#include <stdlib.h>
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NET_IF_H
#include <net/if.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef _WIN32
#include <windows.h>
#endif
#ifdef _WIN32
#include <winsock2.h>
#endif
#ifdef _WIN32
#include <ws2tcpip.h>
#endif
#ifdef HAVE_NETINET_IP_H
#include <netinet/ip.h>
#endif
"

AC_CHECK_HEADERS(
	[net/if.h netinet/ip.h resolv.h sys/un.h sys/kern_control.h],
	,
	,
	[[${SOCKET_INCLUDES}]]
)

AC_CHECK_TYPES(
	[in_addr_t],
	,
	[AC_DEFINE([in_addr_t], [uint32_t], [Workaround missing in_addr_t])],
	[[${SOCKET_INCLUDES}]]
)
AC_CHECK_TYPES(
	[in_port_t],
	,
	[AC_DEFINE([in_port_t], [uint16_t], [Workaround missing in_port_t])],
	[[${SOCKET_INCLUDES}]]
)
AC_CHECK_TYPE(
	[struct iphdr],
	[AC_DEFINE([HAVE_IPHDR], [1], [struct iphdr needed for IPv6 support])],
	,
	[[${SOCKET_INCLUDES}]]
)
AC_CHECK_TYPE(
	[struct msghdr],
	[AC_DEFINE([HAVE_MSGHDR], [1], [struct msghdr needed for extended socket error support])],
	,
	[[${SOCKET_INCLUDES}]]
)
AC_CHECK_TYPE(
	[struct cmsghdr],
	[AC_DEFINE([HAVE_CMSGHDR], [1], [struct cmsghdr needed for extended socket error support])],
	,
	[[${SOCKET_INCLUDES}]]
)
AC_CHECK_TYPE(
	[struct in_pktinfo],
	[AC_DEFINE([HAVE_IN_PKTINFO], [1], [struct in_pktinfo needed for IP_PKTINFO support])],
	,
	[[${SOCKET_INCLUDES}]]
)
AC_CHECK_TYPE(
        [sa_family_t],
        [AC_DEFINE([HAVE_SA_FAMILY_T], [1], [sa_family_t, needed to hold AF_* info])],
        ,
        [[${SOCKET_INCLUDES}]]
)
AC_CHECK_MEMBER(
	[struct in_pktinfo.ipi_spec_dst],
	[AC_DEFINE([HAVE_IPI_SPEC_DST], [1], [struct in_pktinfo.ipi_spec_dst needed for IP_PKTINFO support])],
	,
	[[${SOCKET_INCLUDES}]]
)
AC_CHECK_TYPE(
	[struct sockaddr_in6],
	,
	[AC_MSG_ERROR([struct sockaddr_in6 not found, needed for ipv6 transport support.])],
	[[${SOCKET_INCLUDES}]]
)
AC_CHECK_DECLS(
	[SO_MARK],
	,
	,
	[[${SOCKET_INCLUDES}]]
)

saved_LDFLAGS="$LDFLAGS"
LDFLAGS="$LDFLAGS -Wl,--wrap=exit"
AC_MSG_CHECKING([linker supports --wrap])
AC_LINK_IFELSE(
	[AC_LANG_PROGRAM(
		[[
			void exit(int);
			void __real_exit(int);
			void __wrap_exit(int i) {
				__real_exit(i);
			}
		]],
		[[
			exit(0);
		]]
	)],
	[
		AC_MSG_RESULT([yes])
		have_ld_wrap_support=yes
	],
	[AC_MSG_RESULT([no])],
)
LDFLAGS="$saved_LDFLAGS"

dnl We emulate signals in Windows
AC_CHECK_DECLS(
	[SIGHUP],
	,
	[AC_DEFINE([SIGHUP], [1], [SIGHUP replacement])],
	[[
		#include <signal.h>
	]]
)
AC_CHECK_DECLS(
	[SIGINT],
	,
	[AC_DEFINE([SIGINT], [2], [SIGINT replacement])],
	[[
		#include <signal.h>
	]]
)
AC_CHECK_DECLS(
	[SIGUSR1],
	,
	[AC_DEFINE([SIGUSR1], [10], [SIGUSR1 replacement])],
	[[
		#include <signal.h>
	]]
)
AC_CHECK_DECLS(
	[SIGUSR2],
	,
	[AC_DEFINE([SIGUSR2], [12], [SIGUSR2 replacement])],
	[[
		#include <signal.h>
	]]
)
AC_CHECK_DECLS(
	[SIGTERM],
	,
	[AC_DEFINE([SIGTERM], [15], [SIGTERM replacement])],
	[[
		#include <signal.h>
	]]
)

AC_FUNC_FORK

AC_CHECK_FUNCS([ \
	daemon chroot getpwnam setuid nice system dup dup2 \
	syslog openlog mlockall getrlimit getgrnam setgid \
	setgroups flock time gettimeofday \
	setsid chdir \
	chsize ftruncate execve getpeereid basename dirname access \
	epoll_create strsep \
])

AC_CHECK_LIB(
	[dl],
	[dlopen],
	[DL_LIBS="-ldl"]
)
AC_SUBST([DL_LIBS])

AC_CHECK_LIB(
	[nsl],
	[inet_ntoa],
	[SOCKETS_LIBS="${SOCKETS_LIBS} -lnsl"]
)
AC_CHECK_LIB(
	[socket],
	[socket],
	[SOCKETS_LIBS="${SOCKETS_LIBS} -lsocket"]
)
AC_CHECK_LIB(
	[resolv],
	[gethostbyname],
	[SOCKETS_LIBS="${SOCKETS_LIBS} -lresolv"]
)
AC_SUBST([SOCKETS_LIBS])

old_LIBS="${LIBS}"
LIBS="${LIBS} ${SOCKETS_LIBS}"
AC_CHECK_FUNCS([sendmsg recvmsg])

LIBS="${old_LIBS}"

# we assume res_init() always exist, but need to find out *where*...
AC_SEARCH_LIBS(__res_init, resolv bind, ,
    AC_SEARCH_LIBS(res_9_init, resolv bind, ,
	AC_SEARCH_LIBS(res_init, resolv bind, , )))

AC_ARG_VAR([TAP_CFLAGS], [C compiler flags for tap])
old_CFLAGS="${CFLAGS}"
CFLAGS="${CFLAGS} ${TAP_CFLAGS}"
AC_CHECK_HEADERS(
	[ \
		net/if_tun.h net/tun/if_tun.h \
		linux/if_tun.h \
		tap-windows.h \
	],
	[have_tap_header="yes"]
)
AC_CHECK_DECLS(
	[TUNSETPERSIST],
	[AC_DEFINE([ENABLE_FEATURE_TUN_PERSIST], [1], [We have persist tun capability])],
	,
	[[
		#ifdef HAVE_LINUX_IF_TUN_H
		#include <linux/if_tun.h>
		#endif
	]]
)
CFLAGS="${old_CFLAGS}"
test "${have_tap_header}" = "yes" || AC_MSG_ERROR([no tap header could be found])

AC_CHECK_LIB(
	[selinux],
	[setcon],
	[SELINUX_LIBS="-lselinux"]
)
AC_SUBST([SELINUX_LIBS])

AC_ARG_VAR([LIBPAM_CFLAGS], [C compiler flags for libpam])
AC_ARG_VAR([LIBPAM_LIBS], [linker flags for libpam])
if test -z "${LIBPAM_LIBS}"; then
	AC_CHECK_LIB(
		[pam],
		[pam_start],
		[LIBPAM_LIBS="-lpam"]
	)
fi

case "${with_mem_check}" in
	valgrind)
		AC_CHECK_HEADERS(
			[valgrind/memcheck.h],
			[
				CFLAGS="${CFLAGS} -g -fno-inline"
				AC_DEFINE(
					[USE_VALGRIND],
					[1],
					[Use valgrind memory debugging library]
				)
			],
			[AC_MSG_ERROR([valgrind headers not found.])]
		)
		;;
	dmalloc)
		AC_CHECK_HEADERS(
			[dmalloc.h],
			[AC_CHECK_LIB(
				[dmalloc],
				[malloc],
				[
					LIBS="${LIBS} -ldmalloc"
					AC_DEFINE(
						[DMALLOC],
						[1],
						[Use dmalloc memory debugging library]
					)
				],
				[AC_MSG_ERROR([dmalloc library not found.])]
			)],
			[AC_MSG_ERROR([dmalloc headers not found.])]
		)
		;;
	ssl)
		AC_CHECK_LIB(
			[ssl],
			[CRYPTO_mem_ctrl],
			[
				AC_DEFINE(
					[CRYPTO_MDEBUG],
					[1],
					[Use memory debugging function in OpenSSL]
				)
				AC_MSG_NOTICE([NOTE: OpenSSL library must be compiled with CRYPTO_MDEBUG])
			],
			[AC_MSG_ERROR([Memory Debugging function in OpenSSL library not found.])]
		)
		;;
esac

PKG_CHECK_MODULES(
	[PKCS11_HELPER],
	[libpkcs11-helper-1 >= 1.11],
	[have_pkcs11_helper="yes"],
	[]
)


if test "$enable_dco" != "no"; then
	enable_dco_arg="$enable_dco"
	if test "${enable_iproute2}" = "yes"; then
		AC_MSG_WARN([DCO cannot be enabled when using iproute2])
		enable_dco="no"
	fi
	case "$host" in
		*-*-linux*)
			if test "$enable_dco" = "no"; then
				if test "$enable_dco_arg" = "auto"; then
					AC_MSG_WARN([DCO support disabled])
				else
					AC_MSG_ERROR([DCO support can't be enabled])
				fi
			else
				dnl
				dnl Include generic netlink library used to talk to ovpn-dco
				dnl
				PKG_CHECK_MODULES([LIBNL_GENL],
					  [libnl-genl-3.0 >= 3.4.0],
					  [have_libnl="yes"],
					  [
					   AC_MSG_ERROR([libnl-genl-3.0 package not found or too old. Is the development package and pkg-config ${pkg_config_found} installed? Must be version 3.4.0 or newer for DCO])
					  ]
				)
				OPTIONAL_LIBNL_GENL_CFLAGS="${LIBNL_GENL_CFLAGS}"
				OPTIONAL_LIBNL_GENL_LIBS="${LIBNL_GENL_LIBS}"

				AC_DEFINE(ENABLE_DCO, 1, [Enable shared data channel offload])
				AC_MSG_NOTICE([Enabled ovpn-dco support for Linux])
			fi
			;;
		*-*-freebsd*)
			AC_CHECK_HEADERS([net/if_ovpn.h],
				[
				 LIBS="${LIBS} -lnv"
				 AC_DEFINE(ENABLE_DCO, 1, [Enable data channel offload for FreeBSD])
				 AC_MSG_NOTICE([Enabled ovpn-dco support for FreeBSD])
				],
				[
				 enable_dco="no"
				 AC_MSG_WARN([DCO header not found.])
				]
			)
			if test "$enable_dco" = "no"; then
				if test "$enable_dco_arg" = "auto"; then
					AC_MSG_WARN([DCO support disabled])
				else
					AC_MSG_ERROR([DCO support can't be enabled])
				fi
			fi
			;;
		*-mingw*)
			AC_MSG_NOTICE([NOTE: --enable-dco ignored on Windows because it's always enabled])
			;;
		*)
			AC_MSG_NOTICE([Ignoring --enable-dco on non supported platform])
			;;
	esac
fi

dnl
dnl Depend on libcap-ng on Linux
dnl
case "$host" in
	*-*-linux*)
		PKG_CHECK_MODULES([LIBCAPNG],
				  [libcap-ng],
				  [],
				  [AC_MSG_ERROR([libcap-ng package not found. Is the development package and pkg-config ${pkg_config_found} installed?])]
		)
		AC_CHECK_HEADER([sys/prctl.h],,[AC_MSG_ERROR([sys/prctl.h not found!])])

		OPTIONAL_LIBCAPNG_CFLAGS="${LIBCAPNG_CFLAGS}"
		OPTIONAL_LIBCAPNG_LIBS="${LIBCAPNG_LIBS}"
		AC_DEFINE(HAVE_LIBCAPNG, 1, [Enable libcap-ng support])
	;;
esac


if test "${with_crypto_library}" = "openssl"; then
	AC_ARG_VAR([OPENSSL_CFLAGS], [C compiler flags for OpenSSL])
	AC_ARG_VAR([OPENSSL_LIBS], [linker flags for OpenSSL])

	if test -z "${OPENSSL_CFLAGS}" -a -z "${OPENSSL_LIBS}"; then
		# if the user did not explicitly specify flags, try to autodetect
		PKG_CHECK_MODULES(
			[OPENSSL],
			[openssl >= 1.1.0],
			[have_openssl="yes"],
			[AC_MSG_WARN([OpenSSL not found by pkg-config ${pkg_config_found}])] # If this fails, we will do another test next
		)
		OPENSSL_LIBS=${OPENSSL_LIBS:--lssl -lcrypto}
	fi

	saved_CFLAGS="${CFLAGS}"
	saved_LIBS="${LIBS}"
	CFLAGS="${CFLAGS} ${OPENSSL_CFLAGS}"
	LIBS="${LIBS} ${OPENSSL_LIBS}"

	# If pkgconfig check failed or OPENSSL_CFLAGS/OPENSSL_LIBS env vars
	# are used, check the version directly in the OpenSSL include file
	if test "${have_openssl}" != "yes"; then
		AC_MSG_CHECKING([additionally if OpenSSL is available and version >= 1.1.0])
		AC_COMPILE_IFELSE(
			[AC_LANG_PROGRAM(
				[[
#include <openssl/opensslv.h>
				]],
				[[
/*	     Version encoding: MNNFFPPS - see opensslv.h for details */
#if OPENSSL_VERSION_NUMBER < 0x10100000L
#error OpenSSL too old
#endif
				]]
			)],
			[AC_MSG_RESULT([ok])],
			[AC_MSG_ERROR([OpenSSL version too old])]
		)
	fi

	AC_CHECK_FUNCS([SSL_CTX_new],
				   ,
				   [AC_MSG_ERROR([openssl check failed])]
	)

	if test "${with_openssl_engine}" = "auto"; then
	    AC_COMPILE_IFELSE(
				    [AC_LANG_PROGRAM(
					    [[
	    #include <openssl/opensslv.h>
	    #include <openssl/opensslconf.h>
					    ]],
					    [[
	    /*	     Version encoding: MNNFFPPS - see opensslv.h for details */
	    #if OPENSSL_VERSION_NUMBER >= 0x30000000L
	    #error Engine support disabled by default in OpenSSL 3.0+
	    #endif

	    /*	     BoringSSL and LibreSSL >= 3.8.1 removed engine support */
	    #ifdef OPENSSL_NO_ENGINE
	    #error Engine support disabled in openssl/opensslconf.h
	    #endif
					    ]]
				    )],
				    [have_openssl_engine="yes"],
				    [have_openssl_engine="no"]
	    )
	    if test "${have_openssl_engine}" = "yes"; then
		AC_CHECK_FUNCS(
		    [ \
			ENGINE_load_builtin_engines \
			ENGINE_register_all_complete \
		    ],
		    ,
		    [have_openssl_engine="no"; break]
		)
	    fi
	else
	    have_openssl_engine="${with_openssl_engine}"
	    if test "${have_openssl_engine}" = "yes"; then
		AC_CHECK_FUNCS(
		    [ \
			ENGINE_load_builtin_engines \
			ENGINE_register_all_complete \
		    ],
		    ,
		    [AC_MSG_ERROR([OpenSSL engine support not found])]
		)
	    fi
	fi
	if test "${have_openssl_engine}" = "yes"; then
		AC_DEFINE([HAVE_OPENSSL_ENGINE], [1], [OpenSSL engine support available])
	fi

	AC_CHECK_FUNC(
		[EVP_aes_256_gcm],
		,
		[AC_MSG_ERROR([OpenSSL check for AES-256-GCM support failed])]
	)

	# All supported OpenSSL versions (>= 1.1.0)
	# have this feature
	have_export_keying_material="yes"

	CFLAGS="${saved_CFLAGS}"
	LIBS="${saved_LIBS}"

	AC_DEFINE([ENABLE_CRYPTO_OPENSSL], [1], [Use OpenSSL library])
	CRYPTO_CFLAGS="${OPENSSL_CFLAGS}"
	CRYPTO_LIBS="${OPENSSL_LIBS}"
elif test "${with_crypto_library}" = "mbedtls"; then
	AC_ARG_VAR([MBEDTLS_CFLAGS], [C compiler flags for mbedtls])
	AC_ARG_VAR([MBEDTLS_LIBS], [linker flags for mbedtls])

	saved_CFLAGS="${CFLAGS}"
	saved_LIBS="${LIBS}"

	if test -z "${MBEDTLS_CFLAGS}" -a -z "${MBEDTLS_LIBS}"; then
		# if the user did not explicitly specify flags, try to autodetect
		PKG_CHECK_MODULES([MBEDTLS],
			[mbedtls >= 2.0.0 mbedx509 >= 2.0.0 mbedcrypto >= 2.0.0],
			[have_mbedtls="yes"],
			[LIBS="${LIBS} -lmbedtls -lmbedx509 -lmbedcrypto"]
		)
		# mbedtls might not have pkgconfig integration, so try manually
                if test "${have_mbedtls}" != "yes"; then
			AC_CHECK_LIB(
				[mbedtls],
				[mbedtls_ssl_init],
				[MBEDTLS_LIBS="-lmbedtls -lmbedx509 -lmbedcrypto"],
				[AC_MSG_ERROR([Could not find mbed TLS.])],
				[${PKCS11_HELPER_LIBS}]
			)
		fi
	fi

	CFLAGS="${MBEDTLS_CFLAGS} ${PKCS11_HELPER_CFLAGS} ${CFLAGS}"
	LIBS="${MBEDTLS_LIBS} ${PKCS11_HELPER_LIBS} ${LIBS}"

	AC_MSG_CHECKING([mbedtls version])
	AC_COMPILE_IFELSE(
		[AC_LANG_PROGRAM(
			[[
#include <mbedtls/version.h>
			]],
			[[
#if MBEDTLS_VERSION_NUMBER < 0x02000000 || (MBEDTLS_VERSION_NUMBER >= 0x03000000 && MBEDTLS_VERSION_NUMBER < 0x03020100)
#error invalid version
#endif
			]]
		)],
		[AC_MSG_RESULT([ok])],
		[AC_MSG_ERROR([mbed TLS version >= 2.0.0 or >= 3.2.1 required])]
	)

	AC_CHECK_HEADER(
		psa/crypto.h,
		[AC_DEFINE([HAVE_MBEDTLS_PSA_CRYPTO_H], [1], [yes])],
		[AC_DEFINE([HAVE_MBEDTLS_PSA_CRYPTO_H], [0], [no])]
	)

	AC_CHECK_FUNCS(
		[ \
			mbedtls_cipher_write_tag \
			mbedtls_cipher_check_tag \
		],
		,
		[AC_MSG_ERROR([mbed TLS check for AEAD support failed])]
	)

	AC_CHECK_FUNC(
		[mbedtls_ssl_tls_prf],
		[AC_DEFINE([HAVE_MBEDTLS_SSL_TLS_PRF], [1], [yes])],
		[AC_DEFINE([HAVE_MBEDTLS_SSL_TLS_PRF], [0], [no])]
	)

	have_export_keying_material="yes"
	AC_CHECK_FUNC(
		[mbedtls_ssl_conf_export_keys_ext_cb],
		[AC_DEFINE([HAVE_MBEDTLS_SSL_CONF_EXPORT_KEYS_EXT_CB], [1], [yes])],
		[AC_DEFINE([HAVE_MBEDTLS_SSL_CONF_EXPORT_KEYS_EXT_CB], [0], [no])]
	)
	if test "x$ac_cv_func_mbedtls_ssl_conf_export_keys_ext_cb" != xyes; then
		AC_CHECK_FUNC(
			[mbedtls_ssl_set_export_keys_cb],
			[AC_DEFINE([HAVE_MBEDTLS_SSL_SET_EXPORT_KEYS_CB], [1], [yes])],
			[AC_DEFINE([HAVE_MBEDTLS_SSL_SET_EXPORT_KEYS_CB], [0], [no])]
		)
		if test "x$ac_cv_func_mbedtls_ssl_set_export_keys_cb" != xyes; then
			have_export_keying_material="no"
		fi
	fi

	AC_CHECK_FUNC(
		[mbedtls_ctr_drbg_update_ret],
		AC_DEFINE([HAVE_MBEDTLS_CTR_DRBG_UPDATE_RET], [1],
			  [Use mbedtls_ctr_drbg_update_ret from mbed TLS]),
	)

	CFLAGS="${saved_CFLAGS}"
	LIBS="${saved_LIBS}"
	AC_DEFINE([ENABLE_CRYPTO_MBEDTLS], [1], [Use mbed TLS library])
	CRYPTO_CFLAGS="${MBEDTLS_CFLAGS}"
	CRYPTO_LIBS="${MBEDTLS_LIBS}"

elif test "${with_crypto_library}" = "wolfssl"; then
	AC_ARG_VAR([WOLFSSL_CFLAGS], [C compiler flags for wolfssl. The include directory should
 contain the regular wolfSSL header files but also the wolfSSL OpenSSL header files.
 Ex: -I/usr/local/include -I/usr/local/include/wolfssl])
	AC_ARG_VAR([WOLFSSL_LIBS], [linker flags for wolfssl])

	saved_CFLAGS="${CFLAGS}"
	saved_LIBS="${LIBS}"

	if test -z "${WOLFSSL_CFLAGS}" -a -z "${WOLFSSL_LIBS}"; then
		# if the user did not explicitly specify flags, try to autodetect
		PKG_CHECK_MODULES(
			[WOLFSSL],
			[wolfssl],
			[],
			[AC_MSG_ERROR([Could not find wolfSSL using pkg-config ${pkg_config_found}])]
		)
		PKG_CHECK_VAR(
			[WOLFSSL_INCLUDEDIR],
			[wolfssl],
			[includedir],
			[],
			[AC_MSG_ERROR([Could not find wolfSSL includedir variable.])]
		)
		WOLFSSL_CFLAGS="${WOLFSSL_CFLAGS} -I${WOLFSSL_INCLUDEDIR}/wolfssl"
	fi
	saved_CFLAGS="${CFLAGS}"
	saved_LIBS="${LIBS}"
	CFLAGS="${CFLAGS} ${WOLFSSL_CFLAGS}"
	LIBS="${LIBS} ${WOLFSSL_LIBS}"

	AC_CHECK_LIB(
		[wolfssl],
		[wolfSSL_Init],
		[],
		[AC_MSG_ERROR([Could not link wolfSSL library.])]
	)
	AC_CHECK_HEADER([wolfssl/options.h],,[AC_MSG_ERROR([wolfSSL header wolfssl/options.h not found!])])

	# wolfSSL signal EKM support
	have_export_keying_material="yes"

	if test "${enable_wolfssl_options_h}" = "yes"; then
		AC_DEFINE([EXTERNAL_OPTS_OPENVPN], [1], [Include options.h from wolfSSL library])
	else
		AC_DEFINE([WOLFSSL_USER_SETTINGS], [1], [Use custom user_settings.h file for wolfSSL library])
	fi

	have_export_keying_material="yes"

	CFLAGS="${saved_CFLAGS}"
	LIBS="${saved_LIBS}"

	AC_DEFINE([ENABLE_CRYPTO_WOLFSSL], [1], [Use wolfSSL crypto library])
	AC_DEFINE([ENABLE_CRYPTO_OPENSSL], [1], [Use wolfSSL openssl compatibility layer])
	CRYPTO_CFLAGS="${WOLFSSL_CFLAGS}"
	CRYPTO_LIBS="${WOLFSSL_LIBS}"
else
	AC_MSG_ERROR([Invalid crypto library: ${with_crypto_library}])
fi

AC_ARG_VAR([LZO_CFLAGS], [C compiler flags for lzo])
AC_ARG_VAR([LZO_LIBS], [linker flags for lzo])
if test -z "${LZO_CFLAGS}" -a -z "${LZO_LIBS}"; then
    # if the user did not explicitly specify flags, try to autodetect
    PKG_CHECK_MODULES([LZO],
		[lzo2],
		[have_lzo="yes"],
		[]
    )

    if test "${have_lzo}" != "yes"; then
	# try to detect without pkg-config
	have_lzo="yes"
	AC_CHECK_LIB(
		[lzo2],
		[lzo1x_1_15_compress],
		[LZO_LIBS="-llzo2"],
		[AC_CHECK_LIB(
			[lzo],
			[lzo1x_1_15_compress],
			[LZO_LIBS="-llzo"],
			[have_lzo="no"]
		)]
	)
    fi
else
    # assume the user configured it correctly
    have_lzo="yes"
fi
if test "${have_lzo}" = "yes"; then
	saved_CFLAGS="${CFLAGS}"
	CFLAGS="${CFLAGS} ${LZO_CFLAGS}"
	AC_CHECK_HEADERS(
		[lzo/lzo1x.h],
		,
		[AC_CHECK_HEADERS(
			[lzo1x.h],
			,
			[AC_MSG_ERROR([lzo1x.h is missing])],
                        [#include <limits.h>
                         #include <lzodefs.h>
                         #include <lzoconf.h>]
		)],
	)
	CFLAGS="${saved_CFLAGS}"
fi

dnl
dnl check for LZ4 library
dnl

AC_ARG_VAR([LZ4_CFLAGS], [C compiler flags for lz4])
AC_ARG_VAR([LZ4_LIBS], [linker flags for lz4])
if test "$enable_lz4" = "yes" && test "$enable_comp_stub" = "no"; then
    if test -z "${LZ4_CFLAGS}" -a -z "${LZ4_LIBS}"; then
	# if the user did not explicitly specify flags, try to autodetect
	PKG_CHECK_MODULES([LZ4],
			  [liblz4 >= 1.7.1 liblz4 < 100],
			  [have_lz4="yes"],
			  [LZ4_LIBS="-llz4"] # If this fails, we will do another test next.
					     # We also add set LZ4_LIBS otherwise the
					     # linker will not know about the lz4 library
	)
    fi

    saved_CFLAGS="${CFLAGS}"
    saved_LIBS="${LIBS}"
    CFLAGS="${CFLAGS} ${LZ4_CFLAGS}"
    LIBS="${LIBS} ${LZ4_LIBS}"

    # If pkgconfig check failed or LZ4_CFLAGS/LZ4_LIBS env vars
    # are used, check the version directly in the LZ4 include file
    if test "${have_lz4}" != "yes"; then
	AC_CHECK_HEADERS([lz4.h],
			 [have_lz4h="yes"],
			 [])

	if test "${have_lz4h}" = "yes" ; then
	    AC_MSG_CHECKING([additionally if system LZ4 version >= 1.7.1])
	    AC_COMPILE_IFELSE(
		[AC_LANG_PROGRAM([[
#include <lz4.h>
				 ]],
				 [[
/* Version encoding: MMNNPP (Major miNor Patch) - see lz4.h for details */
#if LZ4_VERSION_NUMBER < 10701L
#error LZ4 is too old
#endif
				 ]]
				)],
		[
		    AC_MSG_RESULT([ok])
		    have_lz4="yes"
		],
		[AC_MSG_ERROR([system LZ4 library is too old])]
	    )
	fi
    fi

    # Double check we have a few needed functions
    if test "${have_lz4}" = "yes" ; then
	AC_CHECK_LIB([lz4],
		     [LZ4_compress_default],
		     [],
		     [have_lz4="no"])
	AC_CHECK_LIB([lz4],
		     [LZ4_decompress_safe],
		     [],
		     [have_lz4="no"])
    fi

    if test "${have_lz4}" != "yes" ; then
	AC_MSG_ERROR([No compatible LZ4 compression library found. Consider --disable-lz4])
	LZ4_LIBS=""
    fi
    OPTIONAL_LZ4_CFLAGS="${LZ4_CFLAGS}"
    OPTIONAL_LZ4_LIBS="${LZ4_LIBS}"
    AC_DEFINE(ENABLE_LZ4, [1], [Enable LZ4 compression library])
    CFLAGS="${saved_CFLAGS}"
    LIBS="${saved_LIBS}"
fi


dnl
dnl Check for systemd
dnl
AM_CONDITIONAL([ENABLE_SYSTEMD], [test "${enable_systemd}" = "yes"])
if test "$enable_systemd" = "yes" ; then
    PKG_CHECK_MODULES([libsystemd], [systemd libsystemd],
                      [],
                      [PKG_CHECK_MODULES([libsystemd], [libsystemd-daemon])]
                      )

    PKG_CHECK_EXISTS([libsystemd > 216],
                     [AC_DEFINE([SYSTEMD_NEWER_THAN_216], [1],
                           [systemd is newer than v216])]
                    )

    AC_CHECK_HEADERS(systemd/sd-daemon.h,
       ,
       [
	   AC_MSG_ERROR([systemd development headers not found.])
       ])

    saved_LIBS="${LIBS}"
    LIBS="${LIBS} ${libsystemd_LIBS}"
    AC_CHECK_FUNCS([sd_booted], [], [AC_MSG_ERROR([systemd library is missing sd_booted()])])
    OPTIONAL_SYSTEMD_LIBS="${libsystemd_LIBS}"
    AC_DEFINE(ENABLE_SYSTEMD, 1, [Enable systemd integration])
    LIBS="${saved_LIBS}"

    if test -n "${SYSTEMD_UNIT_DIR}"; then
        systemdunitdir="${SYSTEMD_UNIT_DIR}"
    else
        systemdunitdir="\${libdir}/systemd/system"
    fi

    if test -n "${TMPFILES_DIR}"; then
        tmpfilesdir="${TMPFILES_DIR}"
    else
        tmpfilesdir="\${libdir}/tmpfiles.d"
    fi
fi


AC_MSG_CHECKING([git checkout])
GIT_CHECKOUT="no"
if test -n "${GIT}"; then
	if ${GIT} -C "$srcdir" rev-parse --is-inside-work-tree >/dev/null 2>&1; then
		AC_DEFINE([HAVE_CONFIG_VERSION_H], [1], [extra version available in config-version.h])
		GIT_CHECKOUT="yes"
	fi
fi
AC_MSG_RESULT([${GIT_CHECKOUT}])

dnl enable --x509-username-field feature if requested
if test "${enable_x509_alt_username}" = "yes"; then
	if test "${with_crypto_library}" = "mbedtls" ; then
		AC_MSG_ERROR([mbed TLS does not support the --x509-username-field feature])
	fi

	AC_DEFINE([ENABLE_X509ALTUSERNAME], [1], [Enable --x509-username-field feature])
fi

test "${enable_management}" = "yes" && AC_DEFINE([ENABLE_MANAGEMENT], [1], [Enable management server capability])
test "${enable_debug}" = "yes" && AC_DEFINE([ENABLE_DEBUG], [1], [Enable debugging support])
test "${enable_small}" = "yes" && AC_DEFINE([ENABLE_SMALL], [1], [Enable smaller executable size])
test "${enable_fragment}" = "yes" && AC_DEFINE([ENABLE_FRAGMENT], [1], [Enable internal fragmentation support])
test "${enable_port_share}" = "yes" && AC_DEFINE([ENABLE_PORT_SHARE], [1], [Enable TCP Server port sharing])

test "${enable_ntlm}" = "yes" && AC_DEFINE([ENABLE_NTLM], [1], [Enable NTLMv2 proxy support])
test "${enable_crypto_ofb_cfb}" = "yes" && AC_DEFINE([ENABLE_OFB_CFB_MODE], [1], [Enable OFB and CFB cipher modes])
if test "${have_export_keying_material}" = "yes"; then
	AC_DEFINE(
		[HAVE_EXPORT_KEYING_MATERIAL], [1],
		[Crypto library supports keying material exporter]
	)
fi
OPTIONAL_CRYPTO_CFLAGS="${OPTIONAL_CRYPTO_CFLAGS} ${CRYPTO_CFLAGS}"
OPTIONAL_CRYPTO_LIBS="${OPTIONAL_CRYPTO_LIBS} ${CRYPTO_LIBS}"

if test "${enable_plugins}" = "yes"; then
	OPTIONAL_DL_LIBS="${DL_LIBS}"
	AC_DEFINE([ENABLE_PLUGIN], [1], [Enable plug-in support])
else
	enable_plugin_auth_pam="no"
	enable_plugin_down_root="no"
fi

AM_CONDITIONAL([HAVE_SITNL], [false])

if test "${enable_iproute2}" = "yes"; then
	test "${enable_dco}" = "yes" && AC_MSG_ERROR([iproute2 support cannot be enabled when using DCO])
	test -z "${IPROUTE}" && AC_MSG_ERROR([ip utility is required but missing])
	AC_DEFINE([ENABLE_IPROUTE], [1], [enable iproute2 support])
else if test "${have_sitnl}" = "yes"; then
	AC_DEFINE([ENABLE_SITNL], [1], [enable sitnl support])
	AM_CONDITIONAL([HAVE_SITNL], [true])
else if test "${WIN32}" != "yes" -a "${have_sitnl}" != "yes"; then
	test -z "${ROUTE}" && AC_MSG_ERROR([route utility is required but missing])
	test -z "${IFCONFIG}" && AC_MSG_ERROR([ifconfig utility is required but missing])
fi
fi
fi

if test "${enable_selinux}" = "yes"; then
	test -z "${SELINUX_LIBS}" && AC_MSG_ERROR([libselinux required but missing])
	OPTIONAL_SELINUX_LIBS="${SELINUX_LIBS}"
	AC_DEFINE([ENABLE_SELINUX], [1], [SELinux support])
fi

if test "${enable_lzo}" = "yes"; then
	test "${have_lzo}" != "yes" && AC_MSG_ERROR([lzo enabled but missing])
	OPTIONAL_LZO_CFLAGS="${LZO_CFLAGS}"
	OPTIONAL_LZO_LIBS="${LZO_LIBS}"
	AC_DEFINE([ENABLE_LZO], [1], [Enable LZO compression library])
fi
if test "${enable_comp_stub}" = "yes"; then
	test "${enable_lzo}" = "yes" && AC_MSG_ERROR([Cannot have both comp stub and lzo enabled (use --disable-lzo)])
	test "${enable_lz4}" = "yes" && AC_MSG_ERROR([Cannot have both comp stub and LZ4 enabled (use --disable-lz4)])
	AC_DEFINE([ENABLE_COMP_STUB], [1], [Enable compression stub capability])
fi

AM_CONDITIONAL([HAVE_SOFTHSM2], [false])
if test "${enable_pkcs11}" = "yes"; then
	test "${have_pkcs11_helper}" != "yes" && AC_MSG_ERROR([PKCS11 enabled but libpkcs11-helper is missing])
	OPTIONAL_PKCS11_HELPER_CFLAGS="${PKCS11_HELPER_CFLAGS}"
	OPTIONAL_PKCS11_HELPER_LIBS="${PKCS11_HELPER_LIBS}"
	AC_DEFINE([ENABLE_PKCS11], [1], [Enable PKCS11])
	PKG_CHECK_MODULES(
		[P11KIT],
		[p11-kit-1],
		[proxy_module="`$PKG_CONFIG --variable=proxy_module p11-kit-1`"
		 AC_DEFINE_UNQUOTED([DEFAULT_PKCS11_MODULE], "${proxy_module}", [p11-kit proxy])],
		[]
	)
	#
	# softhsm2 for pkcs11 tests
	#
	AC_ARG_VAR([P11TOOL], [full path to p11tool])
	AC_PATH_PROGS([P11TOOL], [p11tool],, [$PATH:/usr/local/bin:/usr/bin:/bin])
	AC_DEFINE_UNQUOTED([P11TOOL_PATH], ["$P11TOOL"], [Path to p11tool])
	AC_ARG_VAR([SOFTHSM2_UTIL], [full path to softhsm2-util])
	AC_ARG_VAR([SOFTHSM2_MODULE], [full path to softhsm2 module @<:@default=/usr/lib/softhsm/libsofthsm2.so@:>@])
	AC_PATH_PROGS([SOFTHSM2_UTIL], [softhsm2-util],, [$PATH:/usr/local/bin:/usr/bin:/bin])
	test -z "$SOFTHSM2_MODULE" && SOFTHSM2_MODULE=/usr/lib/softhsm/libsofthsm2.so
	AC_DEFINE_UNQUOTED([SOFTHSM2_UTIL_PATH], ["$SOFTHSM2_UTIL"], [Path to softhsm2-util])
	AC_DEFINE_UNQUOTED([SOFTHSM2_MODULE_PATH], ["$SOFTHSM2_MODULE"], [Path to softhsm2 module])
	if test "${with_crypto_library}" = "openssl"; then
		AM_CONDITIONAL([HAVE_SOFTHSM2], [test "${P11TOOL}" -a "${SOFTHSM2_UTIL}" -a "${SOFTHSM2_MODULE}"])
	fi
fi

# When testing a compiler option, we add -Werror to force
# an error when the option is unsupported. This is not
# required for gcc, but some compilers such as clang need it.
AC_DEFUN([ACL_CHECK_ADD_COMPILE_FLAGS], [
    old_cflags="$CFLAGS"
    CFLAGS="$1 -Werror $CFLAGS"
    AC_MSG_CHECKING([whether the compiler accepts $1])
    AC_COMPILE_IFELSE([AC_LANG_PROGRAM()], [AC_MSG_RESULT([yes])]; CFLAGS="$1 $old_cflags",
        [AC_MSG_RESULT([no]); CFLAGS="$old_cflags"])]
)

ACL_CHECK_ADD_COMPILE_FLAGS([-Wno-stringop-truncation])
ACL_CHECK_ADD_COMPILE_FLAGS([-Wstrict-prototypes])
ACL_CHECK_ADD_COMPILE_FLAGS([-Wold-style-definition])
ACL_CHECK_ADD_COMPILE_FLAGS([-Wall])

if test "${enable_pedantic}" = "yes"; then
	enable_strict="yes"
	CFLAGS="${CFLAGS} -pedantic"
	AC_DEFINE([PEDANTIC], [1], [Enable pedantic mode])
fi
if test "${enable_strict}" = "yes"; then
	CFLAGS="${CFLAGS} -Wsign-compare -Wuninitialized"
fi
if test "${enable_werror}" = "yes"; then
	CFLAGS="${CFLAGS} -Werror"
fi

if test "${enable_plugin_auth_pam}" = "yes"; then
	PLUGIN_AUTH_PAM_CFLAGS="${LIBPAM_CFLAGS}"
	if test "${enable_pam_dlopen}" = "yes"; then
		AC_DEFINE([USE_PAM_DLOPEN], [1], [dlopen libpam])
		PLUGIN_AUTH_PAM_LIBS="${DL_LIBS}"
	else
		test -z "${LIBPAM_LIBS}" && AC_MSG_ERROR([libpam required but missing])
		PLUGIN_AUTH_PAM_LIBS="${LIBPAM_LIBS}"
	fi
fi

if test "${enable_async_push}" = "yes"; then
	case "$host" in
		*-*-freebsd*)
			PKG_CHECK_MODULES(
				[OPTIONAL_INOTIFY],
				[libinotify],
				[
					AC_DEFINE([HAVE_SYS_INOTIFY_H])
					AC_DEFINE([ENABLE_ASYNC_PUSH], [1], [Enable async push])
				]
			)
		;;
		*)
			AC_CHECK_HEADERS(
				[sys/inotify.h],
				AC_DEFINE([ENABLE_ASYNC_PUSH], [1], [Enable async push]),
				AC_MSG_ERROR([inotify.h not found.])
			)
		;;
	esac
fi

CONFIGURE_DEFINES="`set | grep '^enable_.*=' ; set | grep '^with_.*='`"
AC_DEFINE_UNQUOTED([CONFIGURE_DEFINES], ["`echo ${CONFIGURE_DEFINES}`"], [Configuration settings])

TAP_WIN_COMPONENT_ID="PRODUCT_TAP_WIN_COMPONENT_ID"
TAP_WIN_MIN_MAJOR="PRODUCT_TAP_WIN_MIN_MAJOR"
TAP_WIN_MIN_MINOR="PRODUCT_TAP_WIN_MIN_MINOR"
AC_DEFINE_UNQUOTED([TAP_WIN_COMPONENT_ID], ["${TAP_WIN_COMPONENT_ID}"], [The tap-windows id])
AC_DEFINE_UNQUOTED([TAP_WIN_MIN_MAJOR], [${TAP_WIN_MIN_MAJOR}], [The tap-windows version number is required for OpenVPN])
AC_DEFINE_UNQUOTED([TAP_WIN_MIN_MINOR], [${TAP_WIN_MIN_MINOR}], [The tap-windows version number is required for OpenVPN])
AC_SUBST([TAP_WIN_COMPONENT_ID])
AC_SUBST([TAP_WIN_MIN_MAJOR])
AC_SUBST([TAP_WIN_MIN_MINOR])

AC_SUBST([OPTIONAL_DL_LIBS])
AC_SUBST([OPTIONAL_SELINUX_LIBS])
AC_SUBST([OPTIONAL_CRYPTO_CFLAGS])
AC_SUBST([OPTIONAL_CRYPTO_LIBS])
AC_SUBST([OPTIONAL_LIBCAPNG_CFLAGS])
AC_SUBST([OPTIONAL_LIBCAPNG_LIBS])
AC_SUBST([OPTIONAL_LIBNL_GENL_CFLAGS])
AC_SUBST([OPTIONAL_LIBNL_GENL_LIBS])
AC_SUBST([OPTIONAL_LZO_CFLAGS])
AC_SUBST([OPTIONAL_LZO_LIBS])
AC_SUBST([OPTIONAL_LZ4_CFLAGS])
AC_SUBST([OPTIONAL_LZ4_LIBS])
AC_SUBST([OPTIONAL_SYSTEMD_LIBS])
AC_SUBST([OPTIONAL_PKCS11_HELPER_CFLAGS])
AC_SUBST([OPTIONAL_PKCS11_HELPER_LIBS])
AC_SUBST([OPTIONAL_INOTIFY_CFLAGS])
AC_SUBST([OPTIONAL_INOTIFY_LIBS])

AC_SUBST([PLUGIN_AUTH_PAM_CFLAGS])
AC_SUBST([PLUGIN_AUTH_PAM_LIBS])

AM_CONDITIONAL([WIN32], [test "${WIN32}" = "yes"])
AM_CONDITIONAL([GIT_CHECKOUT], [test "${GIT_CHECKOUT}" = "yes"])
AM_CONDITIONAL([ENABLE_PLUGIN_AUTH_PAM], [test "${enable_plugin_auth_pam}" = "yes"])
AM_CONDITIONAL([ENABLE_PLUGIN_DOWN_ROOT], [test "${enable_plugin_down_root}" = "yes"])
AM_CONDITIONAL([HAVE_LD_WRAP_SUPPORT], [test "${have_ld_wrap_support}" = "yes"])
AM_CONDITIONAL([OPENSSL_ENGINE], [test "${have_openssl_engine}" = "yes"])

sampledir="\$(docdir)/sample"
AC_SUBST([plugindir])
AC_SUBST([sampledir])

AC_SUBST([systemdunitdir])
AC_SUBST([tmpfilesdir])

AC_ARG_ENABLE(
     [unit-tests],
     [AS_HELP_STRING([--disable-unit-tests],
                     [Disables building and running the unit tests suite])],
     [],
     [enable_unit_tests="yes"]
)

# Check if cmocka is available - needed for unit testing
PKG_CHECK_MODULES(
	[CMOCKA], [cmocka],
	[have_cmocka="yes"],
	[AC_MSG_WARN([cmocka.pc not found on the system using pkg-config ${pkg_config_found}.  Unit tests disabled])]
)
AM_CONDITIONAL([ENABLE_UNITTESTS], [test "${enable_unit_tests}" = "yes" -a "${have_cmocka}" = "yes" ])
AC_SUBST([ENABLE_UNITTESTS])

TEST_LDFLAGS="${OPTIONAL_CRYPTO_LIBS} ${OPTIONAL_PKCS11_HELPER_LIBS} ${OPTIONAL_LIBCAPNG_LIBS}"
TEST_LDFLAGS="${TEST_LDFLAGS} ${OPTIONAL_LIBNL_GENL_LIBS}"
TEST_LDFLAGS="${TEST_LDFLAGS} ${OPTIONAL_LZO_LIBS} ${CMOCKA_LIBS}"
TEST_CFLAGS="${OPTIONAL_CRYPTO_CFLAGS} ${OPTIONAL_PKCS11_HELPER_CFLAGS} ${OPTIONAL_LIBCAPNG_CFLAGS}"
TEST_CFLAGS="${TEST_CFLAGS} ${OPTIONAL_LIBNL_GENL_CFLAGS} ${OPTIONAL_LZO_CFLAGS}"
TEST_CFLAGS="${TEST_CFLAGS} -I\$(top_srcdir)/include ${CMOCKA_CFLAGS}"

AC_SUBST([TEST_LDFLAGS])
AC_SUBST([TEST_CFLAGS])

AC_CONFIG_FILES([
	Makefile
	distro/Makefile
	distro/systemd/Makefile
	doc/Makefile
	doc/doxygen/Makefile
	doc/doxygen/openvpn.doxyfile
	include/Makefile
	sample/sample-plugins/Makefile
	src/Makefile
	src/compat/Makefile
	src/openvpn/Makefile
	src/openvpnmsica/Makefile
	src/openvpnserv/Makefile
	src/plugins/Makefile
	src/plugins/auth-pam/Makefile
	src/plugins/down-root/Makefile
	src/tapctl/Makefile
	tests/Makefile
        tests/unit_tests/Makefile
        tests/unit_tests/example_test/Makefile
        tests/unit_tests/openvpn/Makefile
        tests/unit_tests/plugins/Makefile
        tests/unit_tests/plugins/auth-pam/Makefile
	sample/Makefile
])
AC_CONFIG_FILES([tests/t_client.sh], [chmod +x tests/t_client.sh])
AC_OUTPUT