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/* Shared library add-on to iptables for the TTL target
* (C) 2000 by Harald Welte <laforge@gnumonks.org>
*
* This program is distributed under the terms of GNU GPL
*/
#include <stdio.h>
#include <xtables.h>
#include <linux/netfilter_ipv4/ipt_TTL.h>
enum {
O_TTL_SET = 0,
O_TTL_INC,
O_TTL_DEC,
F_TTL_SET = 1 << O_TTL_SET,
F_TTL_INC = 1 << O_TTL_INC,
F_TTL_DEC = 1 << O_TTL_DEC,
F_ANY = F_TTL_SET | F_TTL_INC | F_TTL_DEC,
};
#define s struct ipt_TTL_info
static const struct xt_option_entry TTL_opts[] = {
{.name = "ttl-set", .type = XTTYPE_UINT8, .id = O_TTL_SET,
.excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, ttl)},
{.name = "ttl-dec", .type = XTTYPE_UINT8, .id = O_TTL_DEC,
.excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, ttl),
.min = 1},
{.name = "ttl-inc", .type = XTTYPE_UINT8, .id = O_TTL_INC,
.excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, ttl),
.min = 1},
XTOPT_TABLEEND,
};
#undef s
static void TTL_help(void)
{
printf(
"TTL target options\n"
" --ttl-set value Set TTL to <value 0-255>\n"
" --ttl-dec value Decrement TTL by <value 1-255>\n"
" --ttl-inc value Increment TTL by <value 1-255>\n");
}
static void TTL_parse(struct xt_option_call *cb)
{
struct ipt_TTL_info *info = cb->data;
xtables_option_parse(cb);
switch (cb->entry->id) {
case O_TTL_SET:
info->mode = IPT_TTL_SET;
break;
case O_TTL_DEC:
info->mode = IPT_TTL_DEC;
break;
case O_TTL_INC:
info->mode = IPT_TTL_INC;
break;
}
}
static void TTL_check(struct xt_fcheck_call *cb)
{
if (!(cb->xflags & F_ANY))
xtables_error(PARAMETER_PROBLEM,
"TTL: You must specify an action");
}
static void TTL_save(const void *ip, const struct xt_entry_target *target)
{
const struct ipt_TTL_info *info =
(struct ipt_TTL_info *) target->data;
switch (info->mode) {
case IPT_TTL_SET:
printf(" --ttl-set");
break;
case IPT_TTL_DEC:
printf(" --ttl-dec");
break;
case IPT_TTL_INC:
printf(" --ttl-inc");
break;
}
printf(" %u", info->ttl);
}
static void TTL_print(const void *ip, const struct xt_entry_target *target,
int numeric)
{
const struct ipt_TTL_info *info =
(struct ipt_TTL_info *) target->data;
printf(" TTL ");
switch (info->mode) {
case IPT_TTL_SET:
printf("set to");
break;
case IPT_TTL_DEC:
printf("decrement by");
break;
case IPT_TTL_INC:
printf("increment by");
break;
}
printf(" %u", info->ttl);
}
static struct xtables_target ttl_tg_reg = {
.name = "TTL",
.version = XTABLES_VERSION,
.family = NFPROTO_IPV4,
.size = XT_ALIGN(sizeof(struct ipt_TTL_info)),
.userspacesize = XT_ALIGN(sizeof(struct ipt_TTL_info)),
.help = TTL_help,
.print = TTL_print,
.save = TTL_save,
.x6_parse = TTL_parse,
.x6_fcheck = TTL_check,
.x6_options = TTL_opts,
};
void _init(void)
{
xtables_register_target(&ttl_tg_reg);
}
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