dnl Copyright (c) 1994, 1995, 1996, 1997
dnl     The Regents of the University of California.  All rights reserved.
dnl
dnl Process this file with autoconf to produce a configure script.
dnl

#
# See
#
#       https://ftp.gnu.org/gnu/config/README
#
# for the URLs to use to fetch new versions of config.guess and
# config.sub.
#

AC_PREREQ([2.69])
AC_INIT([tcpdump],[m4_esyscmd_s(cat VERSION)])
AC_CONFIG_SRCDIR(tcpdump.c)

AC_CANONICAL_HOST

AC_LBL_C_INIT_BEFORE_CC(V_INCLS)
#
# Try to enable as many C99 features as we can.
# At minimum, we want C++/C99-style // comments.
#
AC_PROG_CC_C99
if test "$ac_cv_prog_cc_c99" = "no"; then
       AC_MSG_WARN([The C compiler does not support C99; there may be compiler errors])
fi
AC_LBL_C_INIT(V_CCOPT, V_INCLS)
AC_LBL_C_INLINE

AC_CHECK_HEADERS(rpc/rpc.h rpc/rpcent.h net/if.h)
#
# Get the size of a void *, to know whether this is a 32-bit or 64-bit build.
#
AC_CHECK_SIZEOF([void *])

#
# Get the size of a time_t, to know whether it's 32-bit or 64-bit.
#
AC_CHECK_SIZEOF([time_t],,[#include <time.h>])

case "$host_os" in

darwin*)
       AC_ARG_ENABLE(universal,
       AS_HELP_STRING([--disable-universal],[don't build universal on macOS]))
       if test "$enable_universal" != "no"; then
               case "$host_os" in

               darwin9.*)
                       #
                       # Leopard.  Build for x86 and 32-bit PowerPC, with
                       # x86 first.  (That's what Apple does.)
                       #
                       V_CCOPT="$V_CCOPT -arch i386 -arch ppc"
                       LDFLAGS="$LDFLAGS -arch i386 -arch ppc"
                       ;;

               darwin10.*)
                       #
                       # Snow Leopard.  Build for x86-64 and x86, with
                       # x86-64 first.  (That's what Apple does.)
                       #
                       V_CCOPT="$V_CCOPT -arch x86_64 -arch i386"
                       LDFLAGS="$LDFLAGS -arch x86_64 -arch i386"
                       ;;
               esac
       fi
       ;;
esac

#
# Do we have pkg-config?
#
PKG_PROG_PKG_CONFIG

#
# Do we have the brew command from Homebrew?
#
AC_PATH_PROG([BREW], [brew])

AC_ARG_WITH([smi],
  [AS_HELP_STRING([--with-smi],
    [link with libsmi (allows to load MIBs on the fly to decode SNMP packets) [default=yes, if available]])],
  [],
  [with_smi=yes])

if test "x$with_smi" != "xno" ; then
       AC_CHECK_HEADER(smi.h,
       [
               #
               # OK, we found smi.h.  Do we have libsmi with smiInit?
               #
               AC_CHECK_LIB(smi, smiInit,
               [
                       #
                       # OK, we have libsmi with smiInit.  Can we use it?
                       #
                       AC_MSG_CHECKING([whether to enable libsmi])
                       savedlibs="$LIBS"
                       LIBS="-lsmi $LIBS"
                       AC_RUN_IFELSE([AC_LANG_SOURCE([[
/* libsmi available check */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <smi.h>
int main()
{
 int current, revision, age, n;
 const int required = 2;
 if (smiInit(""))
   exit(1);
 if (strcmp(SMI_LIBRARY_VERSION, smi_library_version))
   exit(2);
 n = sscanf(smi_library_version, "%d:%d:%d", &current, &revision, &age);
 if (n != 3)
   exit(3);
 if (required < current - age || required > current)
   exit(4);
 exit(0);
}
                               ]])
                               ],
                               [
                                       AC_MSG_RESULT(yes)
                                       AC_DEFINE(USE_LIBSMI, 1,
                                           [Define if you enable support for libsmi])
                               ],
                               [
                                       dnl autoconf documentation says that
                                       dnl $? contains the exit value.
                                       dnl reality is that it does not.
                                       dnl We leave this in just in case
                                       dnl autoconf ever comes back to
                                       dnl match the documentation.
                                       case $? in
                                         1) AC_MSG_RESULT(no - smiInit failed) ;;
                                         2) AC_MSG_RESULT(no - header/library version mismatch) ;;
                                         3) AC_MSG_RESULT(no - can't determine library version) ;;
                                         4) AC_MSG_RESULT(no - too old) ;;
                                         *) AC_MSG_RESULT(no) ;;
                                       esac
                                       LIBS="$savedlibs"
                               ],
                               [
                                       AC_MSG_RESULT(not when cross-compiling)
                                       LIBS="$savedlibs"
                               ]
                       )
               ])
       ])
fi

AC_MSG_CHECKING([whether to enable the instrument functions code])
AC_ARG_ENABLE([instrument-functions],
  [AS_HELP_STRING([--enable-instrument-functions],
    [enable instrument functions code [default=no]])],
  [],
  [enableval=no])
case "$enableval" in
yes)    AC_MSG_RESULT(yes)
       AC_CHECK_LIB([bfd], [bfd_init],
           [true],
           [AC_MSG_ERROR(
              [--enable-instrument-functions was given, but test for library libbfd failed. Please install the 'binutils-dev' package.])],
           [])
       AC_DEFINE(ENABLE_INSTRUMENT_FUNCTIONS, 1,
           [define if you want to build the instrument functions code])
       LOCALSRC="$LOCALSRC instrument-functions.c"
       # Add '-finstrument-functions' instrumentation option to generate
       # instrumentation calls for entry and exit to functions.
       # Try to avoid Address Space Layout Randomization (ALSR).
       CFLAGS="$CFLAGS -O0 -ggdb -finstrument-functions -fno-stack-protector -fno-pic"
       LDFLAGS="$LDFLAGS -O0 -ggdb -fno-stack-protector -no-pie"
       LIBS="$LIBS -lbfd"
       ;;
*)      AC_MSG_RESULT(no)
       ;;
esac

AC_MSG_CHECKING([whether to enable the possibly-buggy SMB printer])
AC_ARG_ENABLE([smb],
  [AS_HELP_STRING([--enable-smb],
    [enable possibly-buggy SMB printer [default=no]])],
  [],
  [enableval=no])
case "$enableval" in
yes)    AC_MSG_RESULT(yes)
       AC_DEFINE(ENABLE_SMB, 1,
           [define if you want to build the possibly-buggy SMB printer])
       LOCALSRC="print-smb.c smbutil.c $LOCALSRC"
       ;;
*)      AC_MSG_RESULT(no)
       ;;
esac

AC_MSG_CHECKING([whether to drop root privileges by default])
AC_ARG_WITH(
       [user],
       [AS_HELP_STRING([--with-user=USERNAME],
               [drop privileges by default to USERNAME]
       )],
       [],
       [withval=no])
AS_CASE(["$withval"],
       [no], [AC_MSG_RESULT(no)],
       [''|yes], [AC_MSG_ERROR([--with-user requires a username])],
       [
               AC_DEFINE_UNQUOTED(WITH_USER, "$withval",
                   [define if should drop privileges by default])
               AC_MSG_RESULT([yes, to user "$withval"])
       ]
)

AC_MSG_CHECKING([whether to chroot])
AC_ARG_WITH(
       [chroot],
       [AS_HELP_STRING([--with-chroot=DIRECTORY],
               [when dropping privileges, chroot to DIRECTORY]
       )],
       [],
       [withval=no]
)
AS_CASE(["$withval"],
       [no], [AC_MSG_RESULT(no)],
       [''|yes], [AC_MSG_ERROR([--with-chroot requires a directory])],
       [
               AC_DEFINE_UNQUOTED(WITH_CHROOT, "$withval",
                   [define if should chroot when dropping privileges])
               AC_MSG_RESULT([yes, to directory "$withval"])
       ]
)

AC_ARG_WITH(sandbox-capsicum,
       AS_HELP_STRING([--with-sandbox-capsicum],
                      [use Capsicum security functions @<:@default=yes, if available@:>@]))
#
# Check whether various functions are available.  If any are, set
# ac_lbl_capsicum_function_seen to yes; if any are not, set
# ac_lbl_capsicum_function_not_seen to yes.
#
# We don't check cap_rights_init(), as it's a macro, wrapping another
# function, in at least some versions of FreeBSD, and AC_CHECK_FUNCS()
# doesn't handle that.
#
# All of the ones we check for must be available in order to enable
# capsicum sandboxing.
#
# XXX - do we need to check for all of them, or are there some that, if
# present, imply others are present?
#
if test -z "$with_sandbox_capsicum" || test "$with_sandbox_capsicum" != "no" ; then
       #
       # First, make sure we have the required header.
       #
       AC_CHECK_HEADER(sys/capsicum.h,
       [
               #
               # We do; now make sure we have the required functions.
               #
               AC_CHECK_FUNCS(cap_enter cap_rights_limit cap_ioctls_limit openat,
                   ac_lbl_capsicum_function_seen=yes,
                   ac_lbl_capsicum_function_not_seen=yes)
       ])
       AC_CHECK_LIB(casper, cap_init, LIBS="$LIBS -lcasper")
       AC_CHECK_LIB(cap_dns, cap_gethostbyaddr, LIBS="$LIBS -lcap_dns")
fi
AC_MSG_CHECKING([whether to sandbox using capsicum])
if test "x$ac_lbl_capsicum_function_seen" = "xyes" -a "x$ac_lbl_capsicum_function_not_seen" != "xyes"; then
       AC_DEFINE(HAVE_CAPSICUM, 1, [capsicum support available])
       AC_MSG_RESULT(yes)
else
       AC_MSG_RESULT(no)
fi
AC_MSG_CHECKING([whether to sandbox using Casper library])
if test "x$ac_cv_lib_casper_cap_init" = "xyes" -a "x$ac_cv_lib_cap_dns_cap_gethostbyaddr" = "xyes"; then
       AC_DEFINE(HAVE_CASPER, 1, [Casper support available])
       AC_MSG_RESULT(yes)
else
       AC_MSG_RESULT(no)
fi

#
# We must check this before checking whether to check the OS's IPv6,
# support because, on some platforms (such as SunOS 5.x), the test
# program requires the extra networking libraries.
#
AC_LBL_LIBRARY_NET

#
# Check whether AF_INET6 and struct in6_addr are defined.
# If they aren't both defined, we don't have sufficient OS
# support for IPv6, so we don't look for IPv6 support libraries,
# and we define AF_INET6 and struct in6_addr ourselves.
#
AC_MSG_CHECKING([whether the operating system supports IPv6])
AC_COMPILE_IFELSE(
   [
     AC_LANG_SOURCE(
       [[
#include <string.h>
/* AF_INET6 available check */
#include <sys/types.h>
#ifdef _WIN32
#include <ws2tcpip.h>
#else
#include <sys/socket.h>
#include <netinet/in.h>
#endif
#ifdef AF_INET6
void
foo(struct in6_addr *addr)
{
memset(addr, 0, sizeof (struct in6_addr));
}
#else
#error "AF_INET6 not defined"
#endif
       ]])
   ],
   [
       AC_MSG_RESULT(yes)
       AC_DEFINE(HAVE_OS_IPV6_SUPPORT, 1,
           [define if the OS provides AF_INET6 and struct in6_addr])
       ipv6=yes
   ],
   [
       AC_MSG_RESULT(no)
       ipv6=no
   ]
)

ipv6type=unknown
ipv6lib=none
ipv6trylibc=no

if test "$ipv6" = "yes"; then
       AC_MSG_CHECKING([ipv6 stack type])
       for i in inria kame linux-glibc linux-libinet6 toshiba v6d zeta; do
               case $i in
               inria)
                       dnl http://www.kame.net/
                       AC_EGREP_CPP(yes,
[#include <netinet/in.h>
#ifdef IPV6_INRIA_VERSION
yes
#endif],
                               [ipv6type=$i])
                       ;;
               kame)
                       dnl http://www.kame.net/
                       AC_EGREP_CPP(yes,
[#include <netinet/in.h>
#ifdef __KAME__
yes
#endif],
                               [ipv6type=$i;
                               ipv6lib=inet6;
                               ipv6libdir=/usr/local/v6/lib;
                               ipv6trylibc=yes])
                       ;;
               linux-glibc)
                       dnl http://www.v6.linux.or.jp/
                       AC_EGREP_CPP(yes,
[#include <features.h>
#if defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1
yes
#endif],
                               [ipv6type=$i])
                       ;;
               linux-libinet6)
                       dnl http://www.v6.linux.or.jp/
                       dnl
                       dnl This also matches Solaris 8 and Tru64 UNIX 5.1,
                       dnl and possibly other versions of those OSes
                       dnl
                       if test -d /usr/inet6 -o -f /usr/include/netinet/ip6.h; then
                               ipv6type=$i
                               ipv6lib=inet6
                               ipv6libdir=/usr/inet6/lib
                               ipv6trylibc=yes;
                               CFLAGS="-I/usr/inet6/include $CFLAGS"
                       fi
                       ;;
               toshiba)
                       AC_EGREP_CPP(yes,
[#include <sys/param.h>
#ifdef _TOSHIBA_INET6
yes
#endif],
                               [ipv6type=$i;
                               ipv6lib=inet6;
                               ipv6libdir=/usr/local/v6/lib])
                       ;;
               v6d)
                       AC_EGREP_CPP(yes,
[#include </usr/local/v6/include/sys/v6config.h>
#ifdef __V6D__
yes
#endif],
                               [ipv6type=$i;
                               ipv6lib=v6;
                               ipv6libdir=/usr/local/v6/lib;
                               CFLAGS="-I/usr/local/v6/include $CFLAGS"])
                       ;;
               zeta)
                       AC_EGREP_CPP(yes,
[#include <sys/param.h>
#ifdef _ZETA_MINAMI_INET6
yes
#endif],
                               [ipv6type=$i;
                               ipv6lib=inet6;
                               ipv6libdir=/usr/local/v6/lib])
                       ;;
               esac
               if test "$ipv6type" != "unknown"; then
                       break
               fi
       done
       AC_MSG_RESULT($ipv6type)
fi

if test "$ipv6" = "yes" -a "$ipv6lib" != "none"; then
       if test -d $ipv6libdir -a -f $ipv6libdir/lib$ipv6lib.a; then
               LIBS="-L$ipv6libdir -l$ipv6lib $LIBS"
               echo "You have $ipv6lib library, using it"
       else
               if test "$ipv6trylibc" = "yes"; then
                       echo "You do not have $ipv6lib library, using libc"
               else
                       echo 'Fatal: no $ipv6lib library found.  cannot continue.'
                       echo "You need to fetch lib$ipv6lib.a from appropriate"
                       echo 'ipv6 kit and compile beforehand.'
                       exit 1
               fi
       fi
fi

AC_REPLACE_FUNCS(strlcat strlcpy strdup strsep getservent getopt_long)
AC_CHECK_FUNCS(fork vfork)
AC_CHECK_FUNCS(setlinebuf)

#
# Make sure we have snprintf(); we require it.
#
AC_CHECK_FUNC(snprintf,,
   AC_MSG_ERROR([snprintf() is required but wasn't found]))

#
# It became apparent at some point that using a suitable C99 compiler does not
# automatically mean snprintf(3) implementation in the libc supports all the
# modifiers and specifiers used in the project, so let's test that before the
# build, not after.
#
# Testing the sizeof_t length modifier takes making an snprintf() call and
# comparing the actual result with the expected result.  If this fails, it will
# most likely happen at run time, not compile time.
#
# Testing the 64-bit conversion specifiers in addition to that requires the
# <inttypes.h> header to be present and the macros to be defined, so if this
# fails, it will more likely happen at compile time.
#
AC_MSG_CHECKING([whether snprintf is suitable])
AC_RUN_IFELSE(
   [
       AC_LANG_SOURCE([[
#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include <sys/types.h>

int main()
{
 char buf[100];
 uint64_t t = (uint64_t)1 << 32;

 snprintf(buf, sizeof(buf), "%zu", sizeof(buf));
 if (strncmp(buf, "100", sizeof(buf)))
   return 1;

 snprintf(buf, sizeof(buf), "%zd", -sizeof(buf));
 if (strncmp(buf, "-100", sizeof(buf)))
   return 2;

 snprintf(buf, sizeof(buf), "%" PRId64, -t);
 if (strncmp(buf, "-4294967296", sizeof(buf)))
   return 3;

 snprintf(buf, sizeof(buf), "0o%" PRIo64, t);
 if (strncmp(buf, "0o40000000000", sizeof(buf)))
   return 4;

 snprintf(buf, sizeof(buf), "0x%" PRIx64, t);
 if (strncmp(buf, "0x100000000", sizeof(buf)))
   return 5;

 snprintf(buf, sizeof(buf), "%" PRIu64, t);
 if (strncmp(buf, "4294967296", sizeof(buf)))
   return 6;

 return 0;
}
       ]])
   ],
   [
       AC_MSG_RESULT(yes)
   ],
   [
       AC_MSG_RESULT(no)
       AC_MSG_ERROR(
[The snprintf(3) implementation in this libc is not suitable,
tcpdump would not work correctly even if it managed to compile.])
   ],
   [
       AC_MSG_RESULT(not while cross-compiling)
   ]
)

AC_CHECK_LIB(rpc, main)         dnl It's unclear why we might need -lrpc

dnl Some platforms may need -lnsl for getrpcbynumber.
AC_SEARCH_LIBS(getrpcbynumber, nsl,
   AC_DEFINE(HAVE_GETRPCBYNUMBER, 1, [define if you have getrpcbynumber()]))

AC_LBL_LIBPCAP(V_PCAPDEP, V_INCLS)

#
# Check for these after AC_LBL_LIBPCAP, so we link with the appropriate
# libraries (e.g., "-lsocket -lnsl" on Solaris).
#
# You are in a twisty little maze of UN*Xes, all different.
# Some might not have ether_ntohost().
# Some might have it and declare it in <net/ethernet.h>.
# Some might have it and declare it in <netinet/ether.h>
# Some might have it and declare it in <sys/ethernet.h>.
# Some might have it and declare it in <arpa/inet.h>.
# Some might have it and declare it in <netinet/if_ether.h>.
# Some might have it and not declare it in any header file.
#
# Before you is a C compiler.
#
AC_CHECK_FUNCS(ether_ntohost, [
   AC_CACHE_CHECK(for buggy ether_ntohost, ac_cv_buggy_ether_ntohost, [
       AC_RUN_IFELSE([AC_LANG_SOURCE([[
               #include <netdb.h>
               #include <netinet/ether.h>
               #include <stdlib.h>
               #include <sys/types.h>
               #include <sys/param.h>
               #include <sys/socket.h>

               int
               main(int argc, char **argv)
               {
                       u_char ea[6] = { 0xff, 0xff, 0xff, 0xff, 0xff };
                       char name[MAXHOSTNAMELEN];

                       ether_ntohost(name, (struct ether_addr *)ea);
                       exit(0);
               }
       ]])
       ], [ac_cv_buggy_ether_ntohost=no],
          [ac_cv_buggy_ether_ntohost=yes],
          [ac_cv_buggy_ether_ntohost="not while cross-compiling"])])
   if test "$ac_cv_buggy_ether_ntohost" = "no"; then
       AC_DEFINE(USE_ETHER_NTOHOST, 1,
           [define if you have ether_ntohost() and it works])
   fi
])
if test "$ac_cv_func_ether_ntohost" = yes -a \
   "$ac_cv_buggy_ether_ntohost" = "no"; then
       #
       # OK, we have ether_ntohost().  Is it declared in <net/ethernet.h>?
       #
       # This test fails if we don't have <net/ethernet.h> or if we do
       # but it doesn't declare ether_ntohost().
       #
       AC_CHECK_DECL(ether_ntohost,
           [
               AC_DEFINE(NET_ETHERNET_H_DECLARES_ETHER_NTOHOST,,
                   [Define to 1 if net/ethernet.h declares `ether_ntohost'])
           ],,
           [
#include <net/ethernet.h>
           ])
       #
       # Did that succeed?
       #
       if test "$ac_cv_have_decl_ether_ntohost" != yes; then
               #
               # No, how about <netinet/ether.h>, as on Linux?
               #
               # This test fails if we don't have <netinet/ether.h>
               # or if we do but it doesn't declare ether_ntohost().
               #
               # Unset ac_cv_have_decl_ether_ntohost so we don't
               # treat the previous failure as a cached value and
               # suppress the next test.
               #
               unset ac_cv_have_decl_ether_ntohost
               AC_CHECK_DECL(ether_ntohost,
                   [
                       AC_DEFINE(NETINET_ETHER_H_DECLARES_ETHER_NTOHOST,1,
                           [Define to 1 if netinet/ether.h declares `ether_ntohost'])
                   ],,
                   [
#include <netinet/ether.h>
                   ])
       fi
       #
       # Did that succeed?
       #
       if test "$ac_cv_have_decl_ether_ntohost" != yes; then
               #
               # No, how about <sys/ethernet.h>, as on Solaris 10
               # and later?
               #
               # This test fails if we don't have <sys/ethernet.h>
               # or if we do but it doesn't declare ether_ntohost().
               #
               # Unset ac_cv_have_decl_ether_ntohost so we don't
               # treat the previous failure as a cached value and
               # suppress the next test.
               #
               unset ac_cv_have_decl_ether_ntohost
               AC_CHECK_DECL(ether_ntohost,
                   [
                       AC_DEFINE(SYS_ETHERNET_H_DECLARES_ETHER_NTOHOST,,
                           [Define to 1 if sys/ethernet.h declares `ether_ntohost'])
                   ],,
                   [
#include <sys/ethernet.h>
                   ])
       fi
       #
       # Did that succeed?
       #
       if test "$ac_cv_have_decl_ether_ntohost" != yes; then
               #
               # No, how about <arpa/inet.h>, as in AIX?
               #
               # This test fails if we don't have <arpa/inet.h>
               # (if we have ether_ntohost(), we should have
               # networking, and if we have networking, we should
               # have <arpa/inet.h>) or if we do but it doesn't
               # declare ether_ntohost().
               #
               # Unset ac_cv_have_decl_ether_ntohost so we don't
               # treat the previous failure as a cached value and
               # suppress the next test.
               #
               unset ac_cv_have_decl_ether_ntohost
               AC_CHECK_DECL(ether_ntohost,
                   [
                       AC_DEFINE(ARPA_INET_H_DECLARES_ETHER_NTOHOST,,
                           [Define to 1 if arpa/inet.h declares `ether_ntohost'])
                   ],,
                   [
#include <arpa/inet.h>
                   ])
       fi
       #
       # Did that succeed?
       #
       if test "$ac_cv_have_decl_ether_ntohost" != yes; then
               #
               # No, how about <netinet/if_ether.h>?
               # On some platforms, it requires <net/if.h> and
               # <netinet/in.h>, and we always include it with
               # both of them, so test it with both of them.
               #
               # This test fails if we don't have <netinet/if_ether.h>
               # and the headers we include before it, or if we do but
               # <netinet/if_ether.h> doesn't declare ether_hostton().
               #
               # Unset ac_cv_have_decl_ether_ntohost so we don't
               # treat the previous failure as a cached value and
               # suppress the next test.
               #
               unset ac_cv_have_decl_ether_ntohost
               AC_CHECK_DECL(ether_ntohost,
                   [
                       AC_DEFINE(NETINET_IF_ETHER_H_DECLARES_ETHER_NTOHOST,,
                           [Define to 1 if netinet/if_ether.h declares `ether_ntohost'])
                   ],,
                   [
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
                   ])
       fi
       #
       # After all that, is ether_ntohost() declared?
       #
       if test "$ac_cv_have_decl_ether_ntohost" = yes; then
               #
               # Yes.
               #
               AC_DEFINE(HAVE_DECL_ETHER_NTOHOST, 1,
                   [Define to 1 if you have the declaration of `ether_ntohost'])
       else
               #
               # No, we'll have to declare it ourselves.
               # Do we have "struct ether_addr" if we include
               # <netinet/if_ether.h>?
               #
               AC_CHECK_TYPES(struct ether_addr,,,
                   [
                       #include <sys/types.h>
                       #include <sys/socket.h>
                       #include <net/if.h>
                       #include <netinet/in.h>
                       #include <netinet/if_ether.h>
                   ])
       fi
fi

dnl
dnl Check for "pcap_list_datalinks()" and use a substitute version if
dnl it's not present.  If it is present, check for "pcap_free_datalinks()";
dnl if it's not present, we don't replace it for now.  (We could do so
dnl on UN*X, but not on Windows, where hilarity ensues if a program
dnl built with one version of the MSVC support library tries to free
dnl something allocated by a library built with another version of
dnl the MSVC support library.)
dnl
AC_CHECK_FUNC(pcap_list_datalinks,
       [
           AC_DEFINE(HAVE_PCAP_LIST_DATALINKS, 1,
               [define if libpcap has pcap_list_datalinks()])
           AC_CHECK_FUNCS(pcap_free_datalinks)
       ],
       [
           AC_LIBOBJ(datalinks)
       ])

dnl
dnl Check for "pcap_datalink_name_to_val()", and use a substitute
dnl version if it's not present.  If it is present, check for
dnl "pcap_datalink_val_to_description()", and if we don't have it,
dnl use a substitute version.
dnl
AC_CHECK_FUNC(pcap_datalink_name_to_val,
       [
           AC_DEFINE(HAVE_PCAP_DATALINK_NAME_TO_VAL, 1,
               [define if libpcap has pcap_datalink_name_to_val()])
           AC_CHECK_FUNC(pcap_datalink_val_to_description,
               AC_DEFINE(HAVE_PCAP_DATALINK_VAL_TO_DESCRIPTION, 1,
                   [define if libpcap has pcap_datalink_val_to_description()]),
               [
                   AC_LIBOBJ(dlnames)
               ])
       ],
       [
           AC_LIBOBJ(dlnames)
       ])

dnl
dnl Check for "pcap_set_datalink()"; you can't substitute for it if
dnl it's absent (it has hooks into libpcap), so just define the
dnl HAVE_ value if it's there.
dnl
AC_CHECK_FUNCS(pcap_set_datalink)

dnl
dnl Check for "pcap_breakloop()"; you can't substitute for it if
dnl it's absent (it has hooks into the live capture routines),
dnl so just define the HAVE_ value if it's there.
dnl
AC_CHECK_FUNCS(pcap_breakloop)

#
# Do we have the new open API?  Check for pcap_create, and assume that,
# if we do, we also have pcap_activate() and the other new routines
# introduced in libpcap 1.0.0.
#
AC_CHECK_FUNCS(pcap_create)
if test $ac_cv_func_pcap_create = "yes" ; then
       #
       # OK, do we have pcap_set_tstamp_type?  If so, assume we have
       # pcap_list_tstamp_types and pcap_free_tstamp_types as well.
       #
       AC_CHECK_FUNCS(pcap_set_tstamp_type)
       #
       # And do we have pcap_set_tstamp_precision?  If so, we assume
       # we also have pcap_open_offline_with_tstamp_precision.
       #
       AC_CHECK_FUNCS(pcap_set_tstamp_precision)
fi

#
# Check for a miscellaneous collection of functions which we use
# if we have them.
#
AC_CHECK_FUNCS(pcap_findalldevs)
AC_CHECK_FUNCS(pcap_dump_flush pcap_lib_version)
if test $ac_cv_func_pcap_lib_version = "no" ; then
   AC_MSG_CHECKING(whether pcap_version is defined by libpcap)
   AC_LINK_IFELSE([AC_LANG_PROGRAM([[]], [[
       extern char pcap_version[];

       return (int)pcap_version;
      ]])
      ],
      [ac_lbl_cv_pcap_version_defined=yes],
      [ac_lbl_cv_pcap_version_defined=no])
   if test "$ac_lbl_cv_pcap_version_defined" = yes ; then
       AC_MSG_RESULT(yes)
       AC_DEFINE(HAVE_PCAP_VERSION, 1, [define if libpcap has pcap_version])
   else
       AC_MSG_RESULT(no)
   fi
fi
AC_CHECK_FUNCS(pcap_setdirection pcap_set_immediate_mode pcap_dump_ftell64)
#
# See the comment in AC_LBL_LIBPCAP in aclocal.m4 for the reason
# why we don't check for remote-capture APIs if we're building
# with the system libpcap on macOS.
#
if test "$_dont_check_for_remote_apis" != "yes"; then
       AC_CHECK_FUNCS(pcap_open pcap_findalldevs_ex)
fi
AC_REPLACE_FUNCS(pcap_dump_ftell)

#
# Check for special debugging functions
#
AC_CHECK_FUNCS(pcap_set_parser_debug)
if test "$ac_cv_func_pcap_set_parser_debug" = "no" ; then
       #
       # OK, we don't have pcap_set_parser_debug() to set the libpcap
       # filter expression parser debug flag; can we directly set the
       # flag?
       AC_MSG_CHECKING(whether pcap_debug is defined by libpcap)
       AC_LINK_IFELSE([AC_LANG_PROGRAM([[]], [[
               extern int pcap_debug;

               return pcap_debug;
          ]])
          ],
          [ac_lbl_cv_pcap_debug_defined=yes],
          [ac_lbl_cv_pcap_debug_defined=no])
       if test "$ac_lbl_cv_pcap_debug_defined" = yes ; then
               AC_MSG_RESULT(yes)
               AC_DEFINE(HAVE_PCAP_DEBUG, 1, [define if libpcap has pcap_debug])
       else
               AC_MSG_RESULT(no)
               #
               # OK, what about "yydebug"?
               #
               AC_MSG_CHECKING(whether yydebug is defined by libpcap)
               AC_LINK_IFELSE([AC_LANG_PROGRAM([[]], [[
                       extern int yydebug;

                       return yydebug;
                  ]])
                  ],
                  [ac_lbl_cv_yydebug_defined=yes],
                  [ac_lbl_cv_yydebug_defined=no])
               if test "$ac_lbl_cv_yydebug_defined" = yes ; then
                       AC_MSG_RESULT(yes)
                       AC_DEFINE(HAVE_YYDEBUG, 1, [define if libpcap has yydebug])
               else
                       AC_MSG_RESULT(no)
               fi
       fi
fi
AC_CHECK_FUNCS(pcap_set_optimizer_debug)
AC_REPLACE_FUNCS(bpf_dump)      dnl moved to libpcap in 0.6

#
# Assume V7/BSD convention for man pages (file formats in section 5,
# miscellaneous info in section 7).
#
MAN_FILE_FORMATS=5
MAN_MISC_INFO=7
case "$host_os" in

aix*)
       dnl Workaround to enable certain features
       AC_DEFINE(_SUN,1,[define on AIX to get certain functions])
       ;;

hpux*)
       #
       # Use System V conventions for man pages.
       #
       MAN_FILE_FORMATS=4
       MAN_MISC_INFO=5
       ;;

irix*)
       V_GROUP=sys

       #
       # Use System V conventions for man pages.
       #
       MAN_FILE_FORMATS=4
       MAN_MISC_INFO=5
       ;;

osf*)
       V_GROUP=system

       #
       # Use System V conventions for man pages.
       #
       MAN_FILE_FORMATS=4
       MAN_MISC_INFO=5
       ;;

solaris*)
       #
       # Use System V conventions for man pages.
       #
       MAN_FILE_FORMATS=4
       MAN_MISC_INFO=5
       ;;
esac

#
# Make sure we have a definition for C99's uintptr_t (regardless of
# whether the environment is a C99 environment or not).
#
AC_TYPE_UINTPTR_T

savedcppflags="$CPPFLAGS"
CPPFLAGS="$CPPFLAGS $V_INCLS"

#
# Check whether we have pcap/pcap-inttypes.h.
# If we do, we use that to get the C99 types defined.
#
AC_CHECK_HEADERS(pcap/pcap-inttypes.h)

#
# At compile time HAVE_PCAP_FINDALLDEVS depends on HAVE_PCAP_IF_T.
#
AC_CHECK_TYPES(pcap_if_t, , , [#include <pcap.h>])

CPPFLAGS="$savedcppflags"

#
# Define the old BSD specified-width types in terms of the C99 types;
# we may need them with libpcap include files.
#
AC_CHECK_TYPE([u_int8_t], ,
       [AC_DEFINE([u_int8_t], [uint8_t],
       [Define to `uint8_t' if u_int8_t not defined.])],
       [AC_INCLUDES_DEFAULT
#include <sys/types.h>
])
AC_CHECK_TYPE([u_int16_t], ,
       [AC_DEFINE([u_int16_t], [uint16_t],
       [Define to `uint16_t' if u_int16_t not defined.])],
       [AC_INCLUDES_DEFAULT
#include <sys/types.h>
])
AC_CHECK_TYPE([u_int32_t], ,
       [AC_DEFINE([u_int32_t], [uint32_t],
       [Define to `uint32_t' if u_int32_t not defined.])],
       [AC_INCLUDES_DEFAULT
#include <sys/types.h>
])
AC_CHECK_TYPE([u_int64_t], ,
       [AC_DEFINE([u_int64_t], [uint64_t],
       [Define to `uint64_t' if u_int64_t not defined.])],
       [AC_INCLUDES_DEFAULT
#include <sys/types.h>
])

AC_PROG_RANLIB
AC_CHECK_TOOL([AR], [ar])

AC_LBL_DEVEL(V_CCOPT)

# Check for OpenSSL/libressl libcrypto
AC_MSG_CHECKING(whether to use OpenSSL/libressl libcrypto)
# Specify location for both includes and libraries.
want_libcrypto=ifavailable
AC_ARG_WITH(crypto,
   AS_HELP_STRING([--with-crypto]@<:@=DIR@:>@,
                  [use OpenSSL/libressl libcrypto (located in directory DIR, if specified) @<:@default=yes, if available@:>@]),
[
       if test $withval = no
       then
               # User doesn't want to link with libcrypto.
               want_libcrypto=no
               AC_MSG_RESULT(no)
       elif test $withval = yes
       then
               # User wants to link with libcrypto but hasn't specified
               # a directory.
               want_libcrypto=yes
               AC_MSG_RESULT(yes)
       else
               # User wants to link with libcrypto and has specified
               # a directory, so use the provided value.
               want_libcrypto=yes
               libcrypto_root=$withval
               AC_MSG_RESULT([yes, using the version installed in $withval])
       fi
],[
       #
       # Use libcrypto if it's present, otherwise don't; no directory
       # was specified.
       #
       want_libcrypto=ifavailable
       AC_MSG_RESULT([yes, if available])
])
if test "$want_libcrypto" != "no"; then
       #
       # Were we told where to look for libcrypto?
       #
       if test -z "$libcrypto_root"; then
               #
               # No.
               #
               # First, try looking for it with pkg-config, if we have it.
               #
               # Homebrew's pkg-config does not, by default, look for
               # pkg-config files for packages it has installed.
               # Furthermore, at least for OpenSSL, they appear to be
               # dumped in package-specific directories whose paths are
               # not only package-specific but package-version-specific.
               #
               # So the only way to find openssl is to get the value of
               # PKG_CONFIG_PATH from "brew --env openssl" and add that
               # to PKG_CONFIG_PATH.  (No, we can't just assume it's under
               # /usr/local; Homebrew have conveniently chosen to put it
               # under /opt/homebrew on ARM.)
               #
               # That's the nice thing about Homebrew - it makes things easier!
               # Thanks!
               #
               save_PKG_CONFIG_PATH="$PKG_CONFIG_PATH"
               if test -n "$BREW"; then
                       openssl_pkgconfig_dir=`$BREW --env --plain openssl | sed -n 's/PKG_CONFIG_PATH: //p'`
                       PKG_CONFIG_PATH="$openssl_pkgconfig_dir:$PKG_CONFIG_PATH"
               fi
               PKG_CHECK_MODULE(LIBCRYPTO, libcrypto,
                   [
                       #
                       # We found OpenSSL/libressl libcrypto.
                       #
                       HAVE_LIBCRYPTO=yes
                   ])
               PKG_CONFIG_PATH="$save_PKG_CONFIG_PATH"

               #
               # If it wasn't found, and we have Homebrew installed, see
               # if it's in Homebrew.
               #
               if test "x$HAVE_LIBCRYPTO" != "xyes" -a -n "$BREW"; then
                       AC_MSG_CHECKING(for openssl in Homebrew)
                       #
                       # The brew man page lies when it speaks of
                       # $BREW --prefix --installed <formula>
                       # outputting nothing.  In Homebrew 3.3.16,
                       # it produces output regardless of whether
                       # the formula is installed or not, so we
                       # send the standard output and error to
                       # the bit bucket.
                       #
                       # libcrypto isn't a formula, openssl is a formula.
                       #
                       if $BREW --prefix --installed openssl >/dev/null 2>&1; then
                               #
                               # Yes.  Get the include directory and library
                               # directory.  (No, we can't just assume it's
                               # under /usr/local; Homebrew have conveniently
                               # chosen to put it under /opt/homebrew on ARM.)
                               #
                               AC_MSG_RESULT(yes)
                               HAVE_LIBCRYPTO=yes
                               openssl_path=`$BREW --prefix openssl`
                               LIBCRYPTO_CFLAGS="-I$openssl_path/include"
                               LIBCRYPTO_LIBS="-L$openssl_path/lib -lcrypto"
                       else
                               AC_MSG_RESULT(no)
                       fi
               fi

               #
               # If it wasn't found, and /usr/local/include and /usr/local/lib
               # exist, check if it's in /usr/local.  (We check whether they
               # exist because, if they don't exist, the compiler will warn
               # about that and then ignore the argument, so they test
               # using just the system header files and libraries.)
               #
               # We include the standard include file to 1) make sure that
               # it's installed (if it's just a shared library for the
               # benefit of existing programs, that's not useful) and 2)
               # because SSL_library_init() is a library routine in some
               # versions and a #defined wrapper around OPENSSL_init_ssl()
               # in others.
               #
               if test "x$HAVE_LIBCRYPTO" != "xyes" -a -d "/usr/local/include" -a -d "/usr/local/lib"; then
                       AC_LBL_SAVE_CHECK_STATE
                       CFLAGS="$CFLAGS -I/usr/local/include"
                       LIBS="$LIBS -L/usr/local/lib -lcrypto"
                       AC_MSG_CHECKING(whether we have an OpenSSL/libressl libcrypto in /usr/local that we can use)
                       AC_LINK_IFELSE([AC_LANG_PROGRAM(
                           [[
#include <openssl/evp.h>
                           ]],
                           [[
EVP_CIPHER_CTX_block_size((EVP_CIPHER_CTX *)0);
return 0;
                           ]])],
                           [
                               AC_MSG_RESULT(yes)
                               HAVE_LIBCRYPTO=yes
                               LIBCRYPTO_CFLAGS="-I/usr/local/include"
                               LIBCRYPTO_LIBS="-L/usr/local/lib -lcrypto"
                           ],
                           AC_MSG_RESULT(no))
                       AC_LBL_RESTORE_CHECK_STATE
               fi

               #
               # If it wasn't found, check if it's a system library.
               #
               # We include the standard include file to 1) make sure that
               # it's installed (if it's just a shared library for the
               # benefit of existing programs, that's not useful) and 2)
               # make sure this isn't a newer macOS that provides libcrypto
               # as a shared library but doesn't provide headers - Apple,
               # bless their pointy little heads, apparently ship libcrypto
               # as a library, but not the header files, in El Capitan and
               # later, probably because they don't want you writing nasty
               # portable code that could run on other UN*Xes, they want you
               # writing code that uses their Shiny New Crypto Library and
               # that thus only runs on macOS.
               #
               if test "x$HAVE_LIBCRYPTO" != "xyes"; then
                       AC_LBL_SAVE_CHECK_STATE
                       LIBS="$LIBS -lcrypto"
                       AC_MSG_CHECKING(whether we have a system OpenSSL/libressl that we can use)
                       AC_LINK_IFELSE([AC_LANG_PROGRAM(
                           [[
#include <openssl/evp.h>
                           ]],
                           [[
EVP_CIPHER_CTX_block_size((EVP_CIPHER_CTX *)0);
return 0;
                           ]])],
                           [
                               AC_MSG_RESULT(yes)
                               HAVE_LIBCRYPTO=yes
                               LIBCRYPTO_LIBS="-lcrypto"
                           ],
                           AC_MSG_RESULT(no))
                       AC_LBL_RESTORE_CHECK_STATE
               fi
       else
               #
               # Yes.
               #
               # Look for it there.
               #
               AC_LBL_SAVE_CHECK_STATE
               CFLAGS="$CFLAGS -I$libcrypto_root/include"
               LIBS="$LIBS -L$libcrypto_root/lib -lcrypto"
               AC_MSG_CHECKING(whether we have a system OpenSSL/libressl that we can use)
               AC_LINK_IFELSE([AC_LANG_PROGRAM(
                   [[
#include <openssl/evp.h>
                   ]],
                   [[
EVP_CIPHER_CTX_block_size((EVP_CIPHER_CTX *)0);
return 0;
                   ]])],
                   [
                       AC_MSG_RESULT(yes)
                       HAVE_LIBCRYPTO=yes
                       LIBCRYPTO_CFLAGS="-I$libcrypto_root/include"
                       LIBCRYPTO_LIBS="-L$libcrypto_root/lib -lcrypto"
                   ],
                   AC_MSG_RESULT(no))
               AC_LBL_RESTORE_CHECK_STATE
       fi

       #
       # OK, did we find it?
       #
       if test "x$HAVE_LIBCRYPTO" = "xyes"; then
               AC_DEFINE([HAVE_LIBCRYPTO], [1], [Define to 1 if you have a usable `crypto' library (-lcrypto).])

               #
               # Put the subdirectories of the libcrypto root directory
               # at the end of the header and library search path, to
               # make sure they come after any -I or -L flags for
               # a local libpcap - those must take precedence of any
               # directory that might contain an installed version of
               # libpcap.
               #
               V_INCLS="$V_INCLS $LIBCRYPTO_CFLAGS"
               LIBS="$LIBS $LIBCRYPTO_LIBS"

               #
               # OK, then:
               #
               # 1) do we have EVP_CIPHER_CTX_new?
               # If so, we use it to allocate an EVP_CIPHER_CTX, as
               # EVP_CIPHER_CTX may be opaque; otherwise, we allocate it
               # ourselves.
               #
               # 2) do we have EVP_DecryptInit_ex()?
               # If so, we use it, because we need to be able to make
               # two "initialize the cipher" calls, one with the cipher
               # and key, and one with the IV, and, as of OpenSSL 1.1,
               # You Can't Do That with EVP_DecryptInit(), because a
               # call to EVP_DecryptInit() will unconditionally clear
               # the context, and if you don't supply a cipher, it'll
               # clear the cipher, rendering the context unusable and
               # causing a crash.
               #
               AC_CHECK_FUNCS(EVP_CIPHER_CTX_new EVP_DecryptInit_ex)
       else
               AC_MSG_NOTICE(OpenSSL/libressl libcrypto not found)
       fi
fi

# Check for libcap-ng
AC_MSG_CHECKING(whether to use libcap-ng)
# Specify location for both includes and libraries.
want_libcap_ng=ifavailable
AC_ARG_WITH(cap_ng,
   AS_HELP_STRING([--with-cap-ng],
                  [use libcap-ng @<:@default=yes, if available@:>@]),
[
       if test $withval = no
       then
               want_libcap_ng=no
               AC_MSG_RESULT(no)
       elif test $withval = yes
       then
               want_libcap_ng=yes
               AC_MSG_RESULT(yes)
       fi
],[
       #
       # Use libcap-ng if it's present, otherwise don't.
       #
       want_libcap_ng=ifavailable
       AC_MSG_RESULT([yes, if available])
])
if test "$want_libcap_ng" != "no"; then
       AC_CHECK_LIB(cap-ng, capng_change_id)
       AC_CHECK_HEADERS(cap-ng.h)
fi

dnl
dnl set additional include path if necessary
if test "$missing_includes" = "yes"; then
       CPPFLAGS="$CPPFLAGS -I$srcdir/missing"
       V_INCLS="$V_INCLS -I$srcdir/missing"
fi

AC_SUBST(V_CCOPT)
AC_SUBST(V_DEFS)
AC_SUBST(V_INCLS)
AC_SUBST(V_PCAPDEP)
AC_SUBST(LOCALSRC)
AC_SUBST(MAN_FILE_FORMATS)
AC_SUBST(MAN_MISC_INFO)

AC_PROG_INSTALL

AC_CONFIG_HEADER(config.h)

AC_CONFIG_COMMANDS([.devel],[[if test -f .devel; then
       echo timestamp > stamp-h
       cat $srcdir/Makefile-devel-adds >> Makefile
       make depend || exit 1
fi]],[[]])
AC_CONFIG_FILES([Makefile tcpdump.1])
AC_OUTPUT
exit 0