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/*
* IPv6 Hop Limit Target module
* Maciej Soltysiak <solt@dns.toxicfilms.tv>
* Based on HW's ttl target
* This program is distributed under the terms of GNU GPL
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <ip6tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter_ipv6/ip6t_HL.h>
#define IP6T_HL_USED 1
static void init(struct ip6t_entry_target *t, unsigned int *nfcache)
{
}
static void help(void)
{
printf(
"HL target v%s options\n"
" --hl-set value Set HL to <value>\n"
" --hl-dec value Decrement HL by <value>\n"
" --hl-inc value Increment HL by <value>\n"
, IPTABLES_VERSION);
}
static int parse(int c, char **argv, int invert, unsigned int *flags,
const struct ip6t_entry *entry,
struct ip6t_entry_target **target)
{
struct ip6t_HL_info *info = (struct ip6t_HL_info *) (*target)->data;
u_int8_t value;
if (*flags & IP6T_HL_USED) {
exit_error(PARAMETER_PROBLEM,
"Can't specify HL option twice");
}
if (!optarg)
exit_error(PARAMETER_PROBLEM,
"HL: You must specify a value");
if (check_inverse(optarg, &invert, NULL, 0))
exit_error(PARAMETER_PROBLEM,
"HL: unexpected `!'");
value = atoi(optarg);
switch (c) {
case '1':
info->mode = IP6T_HL_SET;
break;
case '2':
if (value == 0) {
exit_error(PARAMETER_PROBLEM,
"HL: decreasing by 0?");
}
info->mode = IP6T_HL_DEC;
break;
case '3':
if (value == 0) {
exit_error(PARAMETER_PROBLEM,
"HL: increasing by 0?");
}
info->mode = IP6T_HL_INC;
break;
default:
return 0;
}
info->hop_limit = value;
*flags |= IP6T_HL_USED;
return 1;
}
static void final_check(unsigned int flags)
{
if (!(flags & IP6T_HL_USED))
exit_error(PARAMETER_PROBLEM,
"HL: You must specify an action");
}
static void save(const struct ip6t_ip6 *ip,
const struct ip6t_entry_target *target)
{
const struct ip6t_HL_info *info =
(struct ip6t_HL_info *) target->data;
switch (info->mode) {
case IP6T_HL_SET:
printf("--hl-set ");
break;
case IP6T_HL_DEC:
printf("--hl-dec ");
break;
case IP6T_HL_INC:
printf("--hl-inc ");
break;
}
printf("%u ", info->hop_limit);
}
static void print(const struct ip6t_ip6 *ip,
const struct ip6t_entry_target *target, int numeric)
{
const struct ip6t_HL_info *info =
(struct ip6t_HL_info *) target->data;
printf("HL ");
switch (info->mode) {
case IP6T_HL_SET:
printf("set to ");
break;
case IP6T_HL_DEC:
printf("decrement by ");
break;
case IP6T_HL_INC:
printf("increment by ");
break;
}
printf("%u ", info->hop_limit);
}
static struct option opts[] = {
{ "hl-set", 1, 0, '1' },
{ "hl-dec", 1, 0, '2' },
{ "hl-inc", 1, 0, '3' },
{ 0 }
};
static
struct ip6tables_target HL = { NULL,
"HL",
IPTABLES_VERSION,
IP6T_ALIGN(sizeof(struct ip6t_HL_info)),
IP6T_ALIGN(sizeof(struct ip6t_HL_info)),
&help,
&init,
&parse,
&final_check,
&print,
&save,
opts
};
void _init(void)
{
register_target6(&HL);
}
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