X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=m4%2Ftuntap.m4;h=8c14a9bcb179f8339bfd1de42461c9966015fedb;hp=975567c7675ba404fab7343f3a7bf43c66b21fdd;hb=5219ee25a248fe26055e54215c5027cbf8483439;hpb=ba6b8005ebe3a53877590c242ff581dc5dee5eae

diff --git a/m4/tuntap.m4 b/m4/tuntap.m4
index 975567c7..8c14a9bc 100644
--- a/m4/tuntap.m4
+++ b/m4/tuntap.m4
@@ -1,20 +1,44 @@
 dnl Check to find out whether the running kernel has support for TUN/TAP
 
-AC_DEFUN(tinc_TUNTAP,
+AC_DEFUN([tinc_TUNTAP],
 [
-AC_CACHE_CHECK([for linux/if_tun.h], tinc_cv_linux_if_tun_h,
-[ AC_TRY_COMPILE([#include <linux/if_tun.h>],
-  [int a = IFF_TAP],
-  if_tun_h="linux/if_tun.h",
-  if_tun_h="no")
-   if test $if_tun_h = no; then
-    AC_MSG_RESULT(none)
-  else
-    AC_DEFINE(HAVE_TUNTAP)
-    AC_DEFINE_UNQUOTED(LINUX_IF_TUN_H, "$if_tun_h")
-    AC_SUBST(LINUX_IF_TUN_H)
-    AC_MSG_RESULT($if_tun_h)
+  AC_ARG_WITH(kernel,
+    AS_HELP_STRING([--with-kernel=DIR], [give the directory with kernel sources (default: /usr/src/linux)]),
+    kerneldir="$withval",
+    kerneldir="/usr/src/linux"
+  )
+  
+  AC_CACHE_CHECK([for linux/if_tun.h], tinc_cv_linux_if_tun_h,
+  [ 
+    AC_COMPILE_IFELSE(
+      AC_LANG_PROGRAM([
+        #include "$kerneldir/include/linux/if_tun.h"
+	int a = IFF_TAP;
+      ]),
+      [if_tun_h="\"$kerneldir/include/linux/if_tun.h\""],
+      [AC_COMPILE_IFELSE(
+        AC_LANG_PROGRAM([
+	  #include <linux/if_tun.h>
+          int a = IFF_TAP;
+	]),
+        [if_tun_h="default"],
+        [if_tun_h="no"]
+      )]
+    )
+  
+    if test $if_tun_h = no; then
+      tinc_cv_linux_if_tun_h=none
+    else
+      tinc_cv_linux_if_tun_h="$if_tun_h"
+    fi
+  ])
+  
+  if test $tinc_cv_linux_if_tun_h != none; then
+    AC_DEFINE(HAVE_TUNTAP, 1, [Universal tun/tap driver present])
+    if test $tinc_cv_linux_if_tun_h != default; then
+     AC_DEFINE_UNQUOTED(LINUX_IF_TUN_H, $tinc_cv_linux_if_tun_h, [Location of if_tun.h])
+    fi
   fi
+  AC_SUBST(LINUX_IF_TUN_H)
   AC_SUBST(HAVE_TUNTAP)
 ])
-])