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libip6t_HL.c
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/*
* IPv6 Hop Limit Target module
* Maciej Soltysiak <[email protected]>
* Based on HW's ttl target
* This program is distributed under the terms of GNU GPL
*/
#include <stdio.h>
#include <xtables.h>
#include <linux/netfilter_ipv6/ip6t_HL.h>
enum {
O_HL_SET = 0,
O_HL_INC,
O_HL_DEC,
F_HL_SET = 1 << O_HL_SET,
F_HL_INC = 1 << O_HL_INC,
F_HL_DEC = 1 << O_HL_DEC,
F_ANY = F_HL_SET | F_HL_INC | F_HL_DEC,
};
#define s struct ip6t_HL_info
static const struct xt_option_entry HL_opts[] = {
{.name = "hl-set", .type = XTTYPE_UINT8, .id = O_HL_SET,
.excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit)},
{.name = "hl-dec", .type = XTTYPE_UINT8, .id = O_HL_DEC,
.excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit),
.min = 1},
{.name = "hl-inc", .type = XTTYPE_UINT8, .id = O_HL_INC,
.excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, hop_limit),
.min = 1},
XTOPT_TABLEEND,
};
#undef s
static void HL_help(void)
{
printf(
"HL target options\n"
" --hl-set value Set HL to <value 0-255>\n"
" --hl-dec value Decrement HL by <value 1-255>\n"
" --hl-inc value Increment HL by <value 1-255>\n");
}
static void HL_parse(struct xt_option_call *cb)
{
struct ip6t_HL_info *info = cb->data;
xtables_option_parse(cb);
switch (cb->entry->id) {
case O_HL_SET:
info->mode = IP6T_HL_SET;
break;
case O_HL_INC:
info->mode = IP6T_HL_INC;
break;
case O_HL_DEC:
info->mode = IP6T_HL_DEC;
break;
}
}
static void HL_check(struct xt_fcheck_call *cb)
{
if (!(cb->xflags & F_ANY))
xtables_error(PARAMETER_PROBLEM,
"HL: You must specify an action");
}
static void HL_save(const void *ip, const struct xt_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 HL_print(const void *ip, const struct xt_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 xtables_target hl_tg6_reg = {
.name = "HL",
.version = XTABLES_VERSION,
.family = NFPROTO_IPV6,
.size = XT_ALIGN(sizeof(struct ip6t_HL_info)),
.userspacesize = XT_ALIGN(sizeof(struct ip6t_HL_info)),
.help = HL_help,
.print = HL_print,
.save = HL_save,
.x6_parse = HL_parse,
.x6_fcheck = HL_check,
.x6_options = HL_opts,
};
void _init(void)
{
xtables_register_target(&hl_tg6_reg);
}