Print helpful error message on --mktun/--rmtun if not available.

OpenVPN only supports --mktun/--rmtun to create/destroy persistant tunnels on Linux. On BSD OSes, "ifconfig tun0 create" can do the same job, so we do not actually need to support it - but the previous error message ("unknown option") wasn't helpful. So always accept the option now, and on non-supported systems, direct user to manpage.

Trac #85

Signed-off-by Gert Doering <[email protected]...>

---
 src/openvpn/init.c    | 10 ++++++++--
 src/openvpn/options.c |  2 --
 2 files changed, 8 insertions(+), 4 deletions(-)

src/openvpn/init.c +8 -2

index b97d2da..42cb3e2 100644
@@ -887,7 +887,6 @@ do_genkey (const struct options * options)
 bool
 do_persist_tuntap (const struct options *options)
 {
-#ifdef ENABLE_FEATURE_TUN_PERSIST
   if (options->persist_config)
     {
       /* sanity check on options for --mktun or --rmtun */

@@ -901,14 +900,21 @@ do_persist_tuntap (const struct options *options)
 	)
 	msg (M_FATAL|M_OPTERR,
 	     "options --mktun or --rmtun should only be used together with --dev");
+#ifdef ENABLE_FEATURE_TUN_PERSIST
       tuncfg (options->dev, options->dev_type, options->dev_node,
 	      options->persist_mode,
 	      options->username, options->groupname, &options->tuntap_options);
       if (options->persist_mode && options->lladdr)
         set_lladdr(options->dev, options->lladdr, NULL);
       return true;
-    }
+#else
+      msg( M_FATAL|M_OPTERR,
+	"options --mktun and --rmtun are not available on your operating "
+	"system.  Please check 'man tun' (or 'tap'), whether your system "
+        "supports using 'ifconfig %s create' / 'destroy' to create/remove "
+        "persistant tunnel interfaces.", options->dev );
 #endif
+    }
   return false;
 }
 

src/openvpn/options.c +0 -1

index e8cf06a..4f27336 100644
@@ -7023,7 +7023,6 @@ add_option (struct options *options,
       options->pkcs11_id_management = true;
     }
 #endif
-#ifdef ENABLE_FEATURE_TUN_PERSIST
   else if (streq (p[0], "rmtun"))
     {
       VERIFY_PERMISSION (OPT_P_GENERAL);