Add checks for the presence of the universal tun/tap device driver.

[tinc] / m4 / tuntap.m4

diff --git a/m4/tuntap.m4 b/m4/tuntap.m4
new file mode 100644 (file)
index 0000000..28ddc9e
--- /dev/null
+++ b/m4/tuntap.m4
@@ -0,0 +1,35 @@
+dnl Check to find out whether the running kernel has support for TUN/TAP
+
+AC_DEFUN(tinc_TUNTAP,
+[
+dnl Check for directory with kernel source... (from ALSA)
+AC_CACHE_CHECK([for directory with kernel source], tinc_cv_kerneldir,
+[ AC_ARG_WITH(kernel,
+    [  --with-kernel=dir       give the directory with kernel sources]
+    [                        (default: /usr/src/linux)],
+    kerneldir="$withval", kerneldir="/usr/src/linux")
+  AC_DEFINE_UNQUOTED(CONFIG_TINC_KERNELDIR, "$kerneldir")
+  CONFIG_TINC_KERNELDIR="$kerneldir"
+  AC_SUBST(CONFIG_TINC_KERNELDIR)
+  AC_MSG_RESULT($kerneldir)
+])
+AC_CACHE_CHECK([for linux/if_tun.h], tinc_cv_linux_if_tun_h,
+[ AC_TRY_COMPILE([linux/if_tun.h],
+  [int a = IFF_TAP],
+  if_tun_h="linux/if_tun.h",
+  [ AC_TRY_COMPILE([$kerneldir/include/linux/if_tun.h],
+    [int a = IFF_TAP],
+    if_tun_h="$kerneldir/include/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)
+  fi
+  AC_SUBST(HAVE_TUNTAP)
+])
+])