Use string_to_number. Don't check for no optarg: we set has_arg to 1 in option array, so getopt does that for us.
diff --git a/extensions/libipt_ttl.c b/extensions/libipt_ttl.c
index 523c855..ce87368 100644
--- a/extensions/libipt_ttl.c
+++ b/extensions/libipt_ttl.c
@@ -1,7 +1,7 @@
/* Shared library add-on to iptables to add TTL matching support
* (C) 2000 by Harald Welte <laforge@gnumonks.org>
*
- * $Id: libipt_ttl.c,v 1.6 2002/05/29 13:08:16 laforge Exp $
+ * $Id$
*
* This program is released under the terms of GNU GPL */
@@ -35,14 +35,14 @@
struct ipt_entry_match **match)
{
struct ipt_ttl_info *info = (struct ipt_ttl_info *) (*match)->data;
- u_int8_t value;
+ int value;
check_inverse(optarg, &invert, &optind, 0);
- value = atoi(argv[optind-1]);
- if (!optarg)
+ if (string_to_number(optarg, 0, 255, &value) == -1)
exit_error(PARAMETER_PROBLEM,
- "ttl: You must specify a value");
+ "ttl: Expected value between 0 and 255");
+
switch (c) {
case '2':
if (invert)